BACKGROUND OF THE INVENTION 1. The Field of the Invention.

The present invention relates to insulation materials which can be used anywhere insulation may be needed. More particularly, the present invention is directed to insulative structures that have a hydraulically settable structural matrix. The insulation barriers may comprise a highly foamed, lightweight hydraulically settable material with a low k-factor, or a relatively dense hydraulically settable structural component attached to a more insulative material, including conventional insulation materials.

2. Relevant Technology.

From the beginning, man has labored against nature in his struggle to survive. Man has worked especially hard in the fight to stay warm — first by discovering that skins of beasts provided protection from the cold, and then by discovering that his dwelling place could be protected and insulated in like manner. As man built shelters to control his environment, he found that these structures, lean-tos, or huts made of wood, leaves, or reeds were effective as thermal barriers. As man progressed, he discovered that walls made with adobe, stone, or wood, and roofs made from grass or palm leaves, provided increased insulation. Even cork, where available, was used to insulate buildings.

In modern times, as mankind became more sophisticated, a wide variety of largely synthetic materials were developed which proved to be far superior insulators. However, with each step away from natural substances, mankind not only saw incremental improvements in the ability to insulate, but also huge increases in the

environmental and health problems caused by the various synthetic insulation materials.

A wide variety of inorganic and organic insulating substances have been proven to cause grave health problems in humans, most notably asbestos and urea-formaldehyde foam. In addition, many insulating foams used today are blown with chemical solvents known as chlorofluorocarbons (or "CFC's"), which have been implicated as being responsible for recent thinning in the ozone layer.

Moreover, the best (i.e.. the most insulative per unit of mass) synthetic insulation materials used today are organic foam materials, which tend to be flammable. Not only is the inflammability of such materials dangerous their combustion often releases extremely toxic fumes. Another widely used insulation material is cellulose-based insulation made from shredded paper or other wood pulp products and is also highly inflammable. These insulation materials often facilitate the incineration of the building they are intended to insulate while exposing the occupants to deadly or highly toxic, gases. Even fiberglass insulation, which is nonflammable, is often coated with certain organic-based (and flammable) materials to increase its workability. However, not even fiberglass insulations are completely fire resistant. Generally, there are six basic types of thermal insulation: (1) air film or air layers; (2) closed cellular materials; (3) fibrous materials; (4) flake materials; (5) granular materials; and (6) reflective foils. Many appli¬ cations may combine one or more of these insulation types. Air films or air layers generally consist of a single surface, or a plurality of multiple surfaces, between which only air exists. An example of this is the double-paned or storm window. In addition, the simple shutter takes advantage to some degree of the_ air layer trapped between the shutter and the window being enclosed. Air layers are usually the safest forms of insulation, both from an

environmental and health standpoint; the only variable is the material used to encapsulate the air.

Cellular insulation is composed of porous materials containing numerous small voids of air or gas. Generally, this material is of the closed cell variety, in which each cell is separated from the others by cell windows or thin membranes. Traditionally, cellular insulation has been produced from glass, plastics, and rubber. Common thermal insulation materials of this type include cellular glass, expanded elastomeric foam, polystyrene foam, polyisocyanate foam, polyurethane foam, and urea-formaldehyde foam. Except for cellular glass, the latter insulation materials are highly inflammable and release toxic (and even deadly) fumes when ignited.

Moreover, urea-formaldehyde foam insulation ("UFFI") , which became very popular in the 1970's during the energy crisis because of the ease in which it could be used to retrofit houses and buildings, has recently been implicated as causing numerous illnesses and respiratory problems. One notable and dangerous problem is that UFFI is known to release substantial quantities of formaldehyde over time.

Formaldehyde can be very toxic to humans, is irritating to mucous membranes, and is thought to be carcinogenic according to some experts. It is the major constituent of embalming fluid. Epidemiologic evidence indicates that adverse health effects associated with residential exposure to formaldehyde cover a wide range of signs and symptoms, including neurophysiological effects, eye and skin irritations, upper and lower respiratory irritations, pulmonary edema, and headaches. Laboratory rats exposed to only 15 ppm of formaldehyde have developed squamous cell carcinoma in the nasal cavity.

As a result of the dangers relating to human exposure to UFFI, Canada and several states in the United States have banned the use of UFFI. Estimates of the number of

homes insulated with UFFI are about 500,000 in the United States and about 100,000 in Canada.

Fibrous insulation is comprised of many small diameter fibers intertwined together to generally form open cell pockets of air between the bundles of fibers. Fibrous insulation may consist of organic materials such as hair, wood, and cane, or may be made from inorganic materials such as glass, rock wool, slag wool, aluminum silicate, asbestos, and carbon. Like the organic foams above, carbon fiber materials are highly inflammable once ignited at high temperature. Except for asbestos, inorganic fibers are generally among the safest insulation materials, although they provide little or no structural support and must contain a structural shell made from metal foil or plastic. As for asbestos, which has been one of the most widely used insulation materials, has been proven to cause a number of severe (or fatal) health problems, including asbestosis and lung cancer. In addition, asbestos insul¬ ation workers often unknowingly ingest large quantities of asbestos, which has been shown to cause in these workers an increase in the incidence of colon cancer. In a study of 17,800 asbestos insulation workers, 59 died of cancer of the colon and rectum, compared to a norm of 38.1. Seikoff, "Mortality Experience of Insulation Workers in the U.S. and Canada: 1943-1976," 330 Annals N.Y. Acad. of Sci. 91-116 (1979) ; see also Miller, "Asbestos Fiber Dust and Gastro¬ intestinal Malignancies: Review of Literature with Regard to Cause/Effect Relationship," 31 J. Chronic Disorders 23- 33 (1978). Flake insulation materials consist of small particles or flakes which may be poured into an air space or bonded together to provide a rigid form of the insulation. Rigid form flake insulation can be used for pipe insulation or for other applications in block or board form. The two types of flake insulation commonly used are perlite and vermiculite. However, unless combined together in some

kind of matrix, they are only useful as loose fill insulators.

Granular insulation is composed of small particles which contain voids or hollow spaces. These hollow spaces can transfer air between the individual voids. The parent material can be magnesia, calcium silicate, diatomaceous earth, or vegetable cork. The first three are commonly used as industrial pipe insulations, while cork is used in low temperature refrigeration applications. Reflective insulation is composed of parallel thin sheets of foil with either high thermal reflectants or low emitants. These thin sheets are spaced to reflect radiant heat back to the source. Each separate sheet provides two heat transfer film coefficients; the air space between two sheets causes a reduction in conduction and convection. Foil insulation is commonly used in specially designed environmental chambers and in high temperature applications where radiative heat transfer is the predominant mode of heat transfer. Another type of insulation material, more akin to the compositions and structures disclosed herein, is insulating concrete. Insulating and lightweight concretes are presently made by special methods, or by the addition of spongy aggregates. Slag may be used for this purpose. AEROCRETE* of the Aerocrete Corp. , is a porous lightweight concrete produced by adding aluminum powder to the hydraulic cement. The aluminum powder reacts with lime present within hydraulic cement to form hydrogen bubbles. DUROX ^® of the U.S. Durox Co., produced as lightweight blocks, panels, and wall units, is a foamed concrete made from a mixture of sand, lime, cement, and gypsum, along with aluminum powder which reacts to produce 3CaO«Al ₂ 0 ₃ and free hydrogen in the form of tiny bubbles. The set material contains about 80% cells, has only about 1/3 the density of ordinary concrete, and has a compressive strength of about 1,000 lb/in ² (6 MPa).

However, the insulating properties of the insulative concretes presently on the market are quite small relative to the insulation ability of the materials typically used in the building industry, like glass wool and organic foams. In addition, the available products are still very heavy compared to glass wool and organic foams. Hence, presently manufactured insulating concrete is limited in use and cannot take the place of conventional insulations used in the building industry or in the manufacture of appliances. Nevertheless, insulating concretes have the advantage of being much safer than most of the insulation materials described above, and are more environmentally benign, since they are essentially comprised of the same components as the earth. In addition, they are fire resistant, nonflammable, and do not emit dangerous or toxic fumes when exposed to fire.

Besides the obvious health hazards of asbestos, UFFI, and ignited organic foams, certain organic foams, such as polystyrene and polyurethane/polyisocyanate foams, also pose grave environmental risks because they often utilize CFC's during their manufacture. They also consume vast amounts of petroleum, an ever diminishing resource, as the starting raw material. As stated above, CFC's have been linked to the destruction of the ozone layer because they release chlorine into the stratosphere, which is readily converted to chlorine monoxide, which in turn is thought to react with and destroy ozone.

Because the ozone layer acts as a filter to remove most of the harmful ultraviolet (or "UV") wavelengths emitted by the sun, it is believed that significant thinning of the ozone layer may, in the future, cause widespread damage to living organisms through excessive exposure to harmful UV light. In particular, excessive exposure to UV radiation causes, sunburning of the skin of humans and animals, in addition to the burning of the retina. There have been numerous studies and reports that

have concluded that further breakdown of the ozone layer may lead to sharp increases in skin cancer and cataracts in humans.

In addition to the chemicals used in the manufacture of insulation products, it is often necessary to dispose of used or scrap insulation itself, which most often ends up in municipal landfills. However, none of the traditional insulation materials is biodegradable except for cellulose- based products. Nevertheless, it is well documented that paper-based products (cellulose) may persist for decades within landfills without decomposing.

From the foregoing, it will be understood that what are needed are new forms of insulation which are not harmful, or which do not pose serious health risks, to the installer or the building dweller.

In addition, it would be a significant improvement over the prior art to provide insulation materials and methods for their manufacture which were more environ¬ mentally neutral and which did not use ozone-depleting chemicals. It would be a significant advancement to provide insulation materials with insulating properties comparable to asbestos, urea formaldehyde foam, or styrofoam, but which did not contribute to environmental or health problems. Further, it would be appreciated that the alternative insulation material would be extremely useful if it could be produced at a cost equal to or even lower than currently used insulation materials. Further, it would be signifi¬ cant that such insulation materials might, in some cases, be both lightweight but have structural support comparable to typical gypsum board.

From a manufacturing perspective, it would be a significant advancement in the art to provide insulation barriers which can be rapidly, formed while maintaining their shape without external support so that the barriers can be handled using conventional manufacturing techniques.

From a safety standpoint, it would be a substantial improvement over the prior art to provide insulation materials which were not only flame retardant, but that were completely nonflammable. It will be appreciated that it would be a major advancement to provide insulation materials which were not only fire resistant, but which also did not produce chemicals harmful to humans and, particularly, which did not cause lung or colon cancer, or asbestosis of the lungs.

It would be an important advancement if such insula¬ tion materials were more readily disposable than current insulation materials used in the construction of buildings, and which had essentially the chemical composition of the earth into which they might eventually be disposed. Such insulation materials and methods for their manufacture are disclosed and claimed herein.

BRIEF SUMMARY AND OBJECTS OF THE INVENTION The present invention encompasses different types of insulation barriers which include a hydraulically settable structural matrix. One embodiment comprises a highly foamed, lightweight insulating material having a hydraul¬ ically settable structural matrix. Another embodiment comprises a laminate insulation barrier which includes one or more layers of a highly insulating material attached to at least one structural layer having a hydraulically settable matrix. The present invention also includes methods for the manufacture of such insulation barriers.

The hydraulically settable structural matrix is formed from the reaction products of a hydraulically settable binder (such as hydraulic cement or gypsum hemihydrate) , water, a fibrous material, appropriate aggregate materials, a rheology modifying agent, and (optionally, dispersants and other admixtures) . It has been found that strong, lightweight, and insulative hydraulically settable materials can be readily and inexpensively manufactured

through innovative processes developed through a micro- structural engineering approach. The insulation barriers within the scope of the present invention are particularly useful in most applications or areas where insulative materials are now used. They are particularly useful in the construction industry because of their low cost and low weight and can insulate building walls and heating and cooling ducts.

Hydraulically settable products, and methods of utilizing them, have literally been known for millennia. While many types of hydraulically settable products have been made, they have typically been extremely bulky and have required significant size and mass in order to posses the desired strength, insulation, and other performance criteria.

While some lightweight and somewhat insulative hydraulically settable products have been made, these products have not been able to achieve a high strength to mass ratio or a high insulation to mass ratios at effective and practical costs. In contrast, the insulation barriers of the present invention are far more insulative, stronger, and versatile than previously known hydraulically settable materials because they incorporate the strength properties of hydraulically settable materials and the insulation properties of conventional insulating materials.

The hydraulically settable materials of the present invention were developed from the perspective of microstructural engineering in order to build into the microstructure of the hydraulically settable composition the desired properties, while at the same time remaining cognizant of costs and manufacturing complications. This microstructural engineering analysis approach, instead of the traditional trial-and-error, mix and test approach, has resulted in the ability to design hydraulically settable materials that have high strength, high insulation, low weight and low cost, and which are environmentally neutral.

The preferred hydraulically settable structural matrix of the present invention includes a hydraulic cement paste (formed from, e.g., a portland-type cement and water) in combination with a rheology-modifying agent such as methyl- hydroxyethylcellulose, an inorganic aggregate material, and fibers. The hydraulically settable material may have relatively high tensile and co pressive strength and toughness in the case where it comprises the structural component in, for example, a laminate insulating barrier.

In embodiments where the hydraulically settable material itself acts as the insulating barrier it will include a component that greatly reduces the density and k- factor, thereby increasing the insulating ability. This insulation enhancing component may include various light¬ weight aggregate materials (like perlite, vermiculite, hollow glass spheres, or aerogels) , finely dispersed air voids, or a combination of the two. These work together to give the necessary strength and insulative properties at a cost which is economically justified from a commercial perspective.

The preferred method of manufacturing a highly insulative hydraulically settable material within the scope of the present invention include the steps of (1) mixing a hydraulically settable binder such as hydraulic cement and water in order to form a hydraulically settable paste; (2) combining a rheology-modifying agent (such as methyl- hydroxyethylcellulose) with the paste such that the resul¬ tant hydraulically settable mixture develops a more plastic-like rheology; (3) adding an aggregate material and/or entrained air to the hydraulically settable mixture in order to impart the desired lightweight properties to the mixture; (4) adding a fibrous material (such as abaca, glass, plastic, or metal fiber) which preferably has a high aspect (length to width) ratio to the hydraulically settable mixture in order to increase toughness and strength; (5) molding the hydraulically settable mixture

together with a highly insulative layer to form an insulation barrier of a predetermined shape; and (6) allowing the hydraulically settable mixture to harden or cure into the predetermined shape. Optionally, finely dispersed voids may be incorporated within the hydraul¬ ically settable matrix by the use of an air entraining agent and/or the use of a reactive metal.

In the case where the hydraulically settable material acts mainly as a structural rather than an insulating component, it is preferably molded into a sheet or other appropriate configuration. Thereafter, while in a wet, semi-dry, or dry condition a highly insulative layer is adhered to the hydraulically settable material. The highly insulative layer can be a lightweight, foamed hydraulically settable product formed as above, or else it can be any conventional insulating material such as aerogel, aerogel doped with carbon, sea gel, organic foam. In addition, highly inorganically filled materials without a hydraul¬ ically settable binder may serve as the insulating layer.

In a preferred embodiment the lightweight, highly insulative material is sandwiched together with a stronger hydraulically settable layer to form a laminate insulation structure. This has the effect of maximizing both the insulative ability and the strength of the resulting insulation barrier. For instance, the insulating material will typically be both lightweight and highly insulative, but may lack adequate strength for some applications. On the other hand, hydraulically settable materials of the present invention which have little or no entrained air but which have fibers and stronger aggregates are not as light¬ weight or insulative but have superior strength properties. A combination of these two types of materials yields a highly insulative barrier with superior strength.

The laminate structure may also include one or more strength enhancing materials which is not a hydraulically settable material, such as plastic, metal foil, paper,

fiberglass or composite fabric, wood, wood pulp, or any other appropriate supporting material known in the art.

Where it is desired that the hydraulically settable material contain finely dispersed voids, such voids can be incorporated through various techniques into the hydraulically settable mixture — one method being the mechanical incorporation of air voids during the mixing process (preferably by means of a high speed, high shear energy mixer) , and another being the generation and incorporation of gas into the hydraulically settable paste in situ by chemical means (such as adding a metal that is readily oxidized in basic cement paste to yield a gas) .

As stated above, the compositions of the present invention can be varied to yield products (or constituent portions of products) of substantially different character. For example, very lightweight insulation products (similar in weight and consistency to styrofoam) , or constituent parts thereof, can be manufactured. For convenience, this first type of insulation product is sometimes herein referred to as a "foam-like" product.

Alternatively, structural matrices that are more rigid, durable and strong can be made according to the present invention. However, even the most durable products of the present invention are much lighter than conventional hydraulic cement products, and typically have a bulk specific gravity less than 2.0 g/cm . This second type of product of the present invention has the appearance of ceramics or pottery and is sometimes herein referred to as a "clay-like" product. In addition, a hybrid "foam-clay" product is also possible.

A key feature of the microstructural engineering design of the present invention is the cost and property optimization of each of the component materials. Further, in many of the preferred embodiments, the mixing of the hydraulically settable paste is performed under high shear energy conditions in order to create a substantially

homogeneous hydraulically settable mixture of all of the components. This greatly increases the strength of the resulting hydraulically settable matrix, while also allowing the entrainment of finely dispersed air voids to reduce the specific gravity (and increase the insulative ability) where desired.

However, high speed, high shear mixing is generally not appropriate when mixing low density aggregates into the hydraulically settable mixture. Such high speed mixing tends to break up and pulverize the lightweight aggregates, thus destroying their lightweight attributes. Instead, after the other components have first been mixed under high energy conditions, lightweight aggregates may then be mixed into the hydraulically settable mixture using low speed, low shear mixing. Nevertheless, it should be understood that heavier aggregates, such as sand, which will not break apart can also be mixed under high shear mixing conditions.

While entraining air is often desirable, it is also possible to incorporate a number of inexpensive gases within the hydraulically settable mixture during high speed mixing. One currently preferred gas is carbon dioxide since it can react with the components of the hydraulically settable paste such as cement paste to increase both the form stability and the "foam stability" of the hydraulic- ally settable mixture. Other factors such as raising the pH and the concentration of alkali metal ions such as sodium and potassium ions increase both the rate and amount of C0 ₂ dissolution within the aqueous layer.

Increasing the form stability and causing early false setting both decrease the cost of manufacture because they allow the molded hydraulically settable material to be handled within a shorter period of time after the formation of the hydraulically settable mixture into the desired shape. On the other hand, foam, stability, or the tendency of the air voids to remain well dispersed throughout the hydraulically settable mixture, increases both the

insulative ability and the strength of the final hardened material.

The molding process can be performed by a variety of well-known methods which have historically been applied to plastic materials, including high pressure extrusion, rolling, jiggering, ram pressing, hot isostatic pressing, injection molding, and other casting and forming methods, such as simply pouring the materials into a mold. While these methods are known in the art in connection with plastics and some ceramic and metal powdered materials, it is only because of the unique microstructural engineering of the present invention that the hydraulically settable mixtures can be molded into a product such as an insulation barrier and still maintain their shape without external support while in the green state.

Indeed, the economic viability of insulation barriers from hydraulically settable materials is primarily possible because the hydraulically settable mixture is fairly self- supporting during the green state and can maintain its molded or cast state throughout the curing process where needed. In addition, the compositions of the present invention importantly provide a hydraulically settable mixture that can rapidly reach a sufficiently high strength so that the molded insulation barriers can be handled and manipulated using conventional means.

Of course, in some applications, such as where a foamed, fluid hydraulically settable mixture is injected into a space (e.g.. between the inner and outer walls of a building or into a mold) , it may be desirable for the hydraulically settable mixture to flow while in the green state. That is the advantage of the microstructural engineering design approach of the present invention; the desired properties and characteristics can be "built" into the desired product. From the foregoing, it will be appreciated that an object of the present invention is the development of

hydraulically settable insulation barriers which do not require the use of environmentally damaging manufacturing methods and raw materials. It will also be appreciated that the insulation barriers of the present invention pose no significant health hazard to the manufacturing techni¬ cian, installer, or end user (building dweller) . Nor do they require large amounts of quickly depleting petroleum resources to supply the necessary parent materials, but are made from materials drawn from the earth. Further, another object and feature of the present invention is the development of hydraulically settable insulation barriers which are more environmentally neutral, both in their manufacture and their disposal, than currently used insulation materials. A still further object and feature of the present invention is the development of hydraulically settable insulation barriers which have the insulating properties of materials such as styrofoam or other organic foams without the disadvantages thereof. One object of the present invention is the development of hydraulically settable insulation barriers which do not release hazardous chem¬ icals like formaldehyde, pentane, and CFC's into the air.

Another object and feature of the present invention is the development of hydraulically settable insulation barriers which are lightweight and yet have a high strength to bulk density ratio to give sufficient structural support for the insulation barrier.

Still another object and feature of the present inven¬ tion is the development of hydraulically settable insula- tion barriers which can be produced inexpensively at costs that are comparable to or lower than existing products.

A still further object and feature of the present invention is the development of hydraulically settable insulation barriers which can maintain their shape without external support during the green state and which rapidly

achieve sufficient strength so that the molded barriers can be handled using conventional means.

Another object and feature of the present invention is the development of hydraulically settable insulation materials which are nonflammable and which do not emit toxic or deadly fumes when exposed to fire.

Finally, another object and feature of the present invention is the development of hydraulically settable insulation materials which essentially have the same chemical composition as the earth into which they will eventually be disposed.

These and other objects and features of the present invention will become more fully apparent from the following description and appended claims, or may be learned by the practice of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to highly insulative barriers for use in most applications where insulation products are presently used. More particularly, the present invention is directed to insulation barriers which include a hydraulically settable structural matrix and which are lightweight, have a high strength to bulk density ratio, are insulative, can be produced cost effectively, and are more environmentally neutral than conventional insulation materials which are often toxic or fatal to the manufacturer, installer, or end user.

The term "insulation barrier" as used in this specification and the appended claims is intended to include insulation materials of essentially any shape presently available on the market, or that may be developed as a result of the teachings herein. Thus, although the insulation barriers may often be planar in shape, curved and even amorphous shapes are, within the scope of the present invention.

Nonlimiting examples of such insulation barriers include laminate insulation barriers, layered and nonlayered insulation blocks placed in attics, walls, floors or anywhere else in a building, materials wrapped or placed around ducts or pipes, foamed insulation injected into spaces such as between two or more walls, and insulating hydraulically settable granules placed between walls or inside spaces. The insulation barriers of the invention will be discussed in further detail below.

More specialized insulating hydraulically settable containers and packaging for food and beverages are disclosed and claimed in related U.S. application Serial No. 08/095,662. In addition, insulating containers and packaging for food and beverages containing a polysacchar- ide, protein, or synthetic organic binder are disclosed and claimed in related U.S. application Serial No. 07/982,383.

I. General Discussion of Materials.

The hydraulically settable insulation barriers within the scope of the present invention can be made to have a variety of densities and physical characteristics, or include integral layers of materials with varying densities, strengths, insulation capabilities, toughness, etc. Both "foam-like" and "clay-like" products can be manufactured according to the present invention, depending upon the concentrations and types of the materials used and the molding, casting, or extrusion process utilized. In addition, products having separate "foam-type" and "clay- type" constituents, can be made according to the present invention.

A. Microstructural Engineering Design.

The hydraulically settable components used in the insulation barriers of the present invention have been developed from the perspective of microstructural engin¬ eering design in order to build into the microstructure of

the hydraulically settable composition certain desired, predetermined properties, while at the same time remaining cognizant of costs and manufacturing complications.

This microstructural engineering analysis approach, in contrast to the traditional trial-and-error mix and test approach, has resulted in the ability to design the hydraulically settable materials with those properties of strength, weight, insulation, cost, and environmental concerns that are necessary for appropriate insulation barriers.

The number of different raw materials available to engineer a specific product is enormous, with estimates ranging from between 50,000-80,000. They can be drawn from such disparately broad classes as metals, polymers, elasto- mers, ceramics, glasses, composites, and hydraulically settable materials such as hydraulic cements. Within a given class of materials, there is some commonality in properties, processing, and use-patterns. Ceramics, for instance, have high modula, while polymers have low modula; metals can be shaped by casting and forging, while composites require lay-up or special molding techniques; hydraulic cement products are rigid and have high compressive strength, while elastomers are less rigid and highly flexible. However, this compartmentalization has its dangers; it can lead to specialization (the metallurgist who knows nothing of ceramics) and to conservative thinking ("we use steel because that is what we have always used"). It is this specialization and conservative thinking that has limited the consideration of using hydraulically settable materials for a variety of products, such as in making insulation barriers for home and building construction or in the manufacture of appliances. Nevertheless, once it is realized that hydraulically settable materials have such a wide utility and can be designed and microstructurally

engineered, their applicability to a variety of possible products becomes obvious.

The design of the compositions of the present invention has been developed and narrowed, first by primary constraints dictated by the design, and then by seeking the subset of materials which maximize the performance of the components. At all times during the process, however, it is important to realize the necessity of designing products which can be manufactured by a cost-competitive process.

Primary constraints in materials selection are imposed by characteristics of the design of a component which are critical to a successful product. With respect to an insulation barrier, those primary constraints include minimal weight and maximum strength and toughness require¬ ments, while simultaneously keeping the costs comparable to substitutable counterparts, such as glass wool, gypsum board, organic foam, or asbestos.

Obviously, one of the problems with hydraulically settable materials in the past has been that typical hydraulically settable mixtures such as cement mixtures are poured into a form, worked, and then allowed to set and cure over a prolonged period of time, typically days or weeks. Experts generally agree that it takes at least one month for traditional concrete products to reach a substantial degree of their optimum strength. (Experts also believe that most concrete products do not reach their maximum strength for several decades.) Such a time period is certainly impractical when manufacturing insulative barriers in bulk or on site. As a result, a critical feature of certain embodiments of the present invention is that when the hydraulically settable mixture is molded it will maintain its shape (i.e., support its own weight subject to minor forces) in the green state without external support. Further, from a manufacturing perspective, in order for production to be economical, it is important for the molded barrier to

rapidly achieve (in a matter of hours, or even minutes) sufficient strength so that it can be handled using conventional methods, even though the hydraulically settable mixture may still be in a green state.

Another advantage of the microstructural engineering design approach of the present invention is the ability to develop compositions in which cross-sections of the structural matrix are more homogeneous than have been typically achieved in the prior art. Ideally, when any two given cross-sections of about 1-2 mm 2 of the hydraulically settable structural matrix are taken, they will have substantially similar amounts of voids, aggregates, fibers, and any other additives or properties of the matrix.

From the following discussion, it will be appreciated how each of the component materials in the hydraulically settable mixture contributes to the primary design constraints. Specific materials and compositions are set forth in the examples to demonstrate how the maximization of the performance of each component accomplishes the combination of desired properties.

B. Hydraulically Settable Materials.

The materials used to manufacture the hydraulically settable insulation barriers of the present invention develop strength through the chemical reaction of water and a hydraulic binder, such as hydraulic cement, calcium sulfate (or gypsum) hemihydrate, and other substances that harden after being exposed to water. The term "hydraulic¬ ally settable materials" as used in this specification and the appended claims includes any material with a structural matrix and strength properties that are derived from a hardening or curing of a hydraulic binder. These include cementitious materials, plasters, and other hydraulically settable materials as defined herein. The hydraulically settable binders used in the present invention are to be distinguished from other cements or binders such as

polymerizable, water insoluble organic cements, glues, or adhesives.

The terms "hydraulically settable materials," "hydraulic cement materials," or "cementitious materials," as used herein, are intended to broadly define compositions and materials that contain both a hydraulically settable binder and water, regardless of the extent of hydration or curing that has taken place. Hence, it is intended that the term "hydraulically settable materials" shall include hydraulic paste or hydraulically settable mixtures in a green (i.e., unhardened) state, as well as hardened hydraulically settable or concrete products. More specifically, the phrase "hydraulically settable mixture" shall refer to a hydraulically settable material that is in a moldable state — that is, it can be shaped without damaging the structure of the final hardened material. Conversely, the term "hydraulically settable matrix" refers to a hydraulically settable material that has attained a significant portion of its final hardened strength.

1. Hydraulically Settable Binders.

The terms "hydraulically settable binder" or "hydraulic binder", as used in this specification and the appended claims, are intended to include any inorganic binder such as hydraulic cement, gypsum hemihydrate, or calcium oxide which develops strength properties and hardness by chemically reacting with water and, in some cases, with carbon dioxide in the air and water. The terms "hydraulic cement" or "cement" as used in this specifica¬ tion and the appended claims are intended to include clinker and crushed, ground, milled, and processed clinker in various stages of pulverization and in various particle sizes.

Examples of hydraulic binders that can be utilized include the broad family of portland cements (including ordinary portland cement without gypsum) , white cement, MDF

cement, DSP cement, Densit-type cements, Pyrament-type cements, calcium aluminate cements (including calcium aluminate cements without set regulators) , plasters, silicate cements (including β-dicalcium silicates, tricalcium silicates, and mixtures thereof) , gypsum cements, gypsum hemihydrate, phosphate cements, high alumina cements, microfine cements, slag cements, magnesium oxychloride cements, calcium oxide, and aggregates coated with microfine cement particles. The term "hydraulic cement" is also intended to include other cements known in the art, such as α-dicalcium silicate, which can be made hydraulic under hydrating conditions within the scope of the present invention.

The basic chemical components of, e.g., portland cement include CaO, Si0 ₂ , A1 ₂ 0 ₃ , Fe ₂ 0 ₃ , MgO, and S0 ₃ , in various combinations and proportions. These react together in the presence of water in a series of complex reactions to form insoluble calcium silicate hydrates, carbonates (from C0 ₂ in the air and added water) , sulfates, and other salts or products of calcium and magnesium, together with hydrates thereof. The aluminum and iron constituents are thought to be incorporated into elaborate complexes within the above mentioned insoluble salts. The cured cement product is a complex matrix of insoluble hydrates and salts that are complexed and linked together much like stone. This material is highly inert and has both physical and chemical properties similar to those of natural stone or dirt.

Gypsum is also a hydraulically settable binder that can be hydrated to form a hardened binding agent. One hydratable form of gypsum is calcium sulfate hemihydrate, commonly known as "gypsum hemihydrate." The hydrated form of gypsum is calcium sulfate dihydrate, commonly known as "gypsum dihydrate." Calcium sulfate hemihydrate can also be mixed with calcium sulfate anhydride, commonly known as "gypsum anhydrite" or simply "anhydrite."

Although gypsum binders or other hydraulic binders such as calcium oxide are generally not as strong as hydraulic cement, high strength may not be as important as other characteristics (e.g., the rate of hardening) in some applications. In terms of cost, gypsum and calcium oxide have an advantage over hydraulic cement because they are somewhat less expensive. Moreover, in the case where the hydraulically settable material contains a relatively high percentage of weak, lighter weight aggregates (such as perlite) , the aggregates will often comprise a "weak link" within the structural matrix. At some point, adding a stronger binder may be inefficient because the binder no longer contributes its higher potential strength due to a high content of weaker aggregates.

In addition, gypsum hemihydrate is known to set up or harden in a much shorter time period than traditional cements. In fact, in use with the present invention, it will harden and attain most of its ultimate strength within about thirty minutes. Hence, gypsum hemihydrate can be used alone or in combination with other hydraulically settable materials within the scope of the present invention.

Terms such as "hydrated" or "cured" when used in con¬ junction with a hydraulically settable mixture, material, or matrix shall refer to a level of substantial water- catalyzed reaction sufficient to produce having a substantial amount of its potential or final maximum strength. Nevertheless, hydraulically settable materials may continue to hydrate long after they have attained significant hardness and a substantial amount of their final maximum strength.

Terms such as "green" or "green state" when used in conjunction with a hydraulically settable mixture shall refer to a mixture that has not achieved a substantial amount of its final strength, regardless of whether such strength is derived from artificial drying, curing, or

other means. Hydraulically settable mixtures are said to be "green" or in a "green state" just prior and subsequent to being molded into the desired shape. The moment when a hydraulically settable mixture is no longer "green" or in a "green state" is not necessarily a clear-cut line of demarcation, since such mixtures generally attain a substantial amount of their total strength only gradually over time. Hydraulically settable mixtures can, of course, show an increase in "green strength" and yet still be "green." For this reason, the discussion herein often refers to the "form stability" of the hydraulically settable material in the green state.

The present invention may include other types of cementitious compositions such as those discussed in copending U.S. patent application Serial No. 07/981,615, filed November 25, 1992 and entitled "Methods of Manufacture And Use For Hydraulically Bonded Cement". In this application, powdered hydraulic cement is placed in a near net final position and compacted prior to the addition of water for hydration.

Additional types of hydraulic cement compositions include those wherein carbon dioxide is mixed with hydraulic cement and water. Hydraulic cement compositions made by this method are known for their ability to more rapidly achieve green strength. This type of hydraulic cement composition is discussed in copending U.S. patent application Serial No. 07/418,027, filed October 10, 1989, and entitled "Process for Producing Improved Building Material and Products Thereof," wherein water and hydraulic cement are mixed in the presence of a carbonate source selected from the group consisting of carbon dioxide, carbon monoxide, carbonate salts, and mixtures thereof.

Preferable hydraulically settable binders include white cement, portland cement, microfine cement, high alumina cement, slag cement, gypsum hemihydrate, and calcium oxide, mainly because of their low cost and

suitability for the manufacturing processes used in the present invention. This list of binders is by no means exhaustive, nor in any way is it intended to limit the types of binders which would be useful in making the hydraulically settable laminate insulation barriers of the invention.

2. Hydraulic Paste.

In each embodiment of the present invention, the hydraulic paste or cement paste is the key constituent which eventually gives the structural portion of the insulation barrier the ability to set up and develop strength properties. The term "hydraulic paste" refers to a hydraulic binder mixed with water. More specifically, the term "cement paste" refers to hydraulic binder such as a cement mixed with water. The terms "hydraulically settable," "hydraulic," or "cementitious" mixture refer to a hydraulic binder such as a cement paste to which aggre¬ gates, fibers, rheology-modifying agents, dispersants, or other materials have been added, whether in the green state or after it has hardened and/or cured. The other ingredients added to the hydraulic paste serve the purpose of altering the properties of the unhardened, as well as the final hardened product, including, but not limited to, strength, shrinkage, flexibility, bulk density, insulating ability, color, porosity, surface finish, and texture.

Although the hydraulically setable binder is under¬ stood as the component which allows the hydraulically settable mixture to set up, to harden, and to achieve much of the strength properties of the material, certain hydraulic binders also aid in the development of better early cohesion and green strength. For example, hydraulic cement particles undergo early gelating reactions with water even before becoming hard, which can contribute to the internal cohesion of the mixture.

It is believed that aluminates, such as those more prevalent in portland grey cement (in the form of tricalcium aluminates) are responsible for a colloidal interaction between the cement particles during the earlier stages of hydration. This in turn causes a level of flocculation/gelation to occur between the cement particles. The gelating, colloidal, and flocculating affects of such binders increases the moldability (i.e., plasticity) of hydraulically settable mixtures made therefrom.

As set forth more fully below, additives such as fibers and rheology-modifying agents can make substantial contributions to the hydraulically settable materials in terms of tensile, flexural, and compressive strengths. Nevertheless, even where high concentrations of fibers and/or rheology-modifying agents are included and contribute substantially to the tensile and flexural strengths of the hardened material, the hydraulic binder continues to add substantial amounts of compressive strength to the final hardened material. In the case of hydraulic cement, the binder also substantially reduces the solubility of the hardened material in water.

The percentage of the hydraulically settable binder within the overall mixture varies depending on the identity of the other added constituents. The hydraulically settable binder is preferably added in an amount ranging from between about 5% to about 95% by weight of the wet hydraulically settable mixture. From the disclosure and examples set forth herein, it will be understood that this wide range of weight percent covers hydraulically settable mixtures used to manufacture foam-like or clay-like materials.

It will be appreciated from the foregoing that embodi¬ ments within the scope of the present invention will vary from a very lightweight "foam-like" product to a somewhat higher density "clay-like" product. Either foam-like or

clay-like materials can readily be molded into the desired insulation barrier, or component thereof. Within these broader categories will be other variations and differences that will require varying quantities and identities of the components. The components and their relative quantities may substantially vary depending upon the specific product to be made.

Generally, when making a "foam-like" insulation product, it will be preferable to include the hydraulically settable binder within a range from between about 1% to about 70% by volume of the total solids of the hydraulic¬ ally settable mixture, and more preferably within a range from between about 5% to about 30% by volume. When making a "clay-like" product (usually as a structural component) , it will be preferable to include the hydraulically settable binder within a range from between 1% to about 70% by volume of the total solids of the hydraulically settable mixture, preferably within a range from about 5% to about 30% by volume, and most preferably within a range from about 5% to about 15% by volume.

Where an insulation barrier is comprised of different layers or components (one layer giving the barrier strength or support and the other giving the barrier its insulative properties) , it is possible, within the scope of the present invention, to include one or more noncementitious binders within the "foam type" insulating component rather than a hydraulic binder. Although methylhydroxyethyl- cellulose is used to add plasticity to, aid the workability of, and increase the thixotropic nature of the hydraulic¬ ally settable mixture of certain embodiments, it has been found to be a good binder in some circumstances, especially in highly foamed, extremely lightweight materials having little or no hydraulically settable binder.

Despite the foregoing, it will be appreciated that all concentrations and amounts are critically dependent upon the qualities and characteristics that are desired in the

final product. For example, in a very thin wall structure (even as thin as 0.05 mm) where strength is needed, it may be more economical to have a very high percentage of hydraulic binder with little or no aggregate. In such a case, it may be desirable to include a high amount of fiber to impart flexibility and toughness. Conversely, in a product in which high amounts of air are incorporated, there may be a greater percentage of the rheology-modifying agent, a smaller amount of hydraulic binder, and larger amounts of lightweight aggregates. Such materials can literally be as light as lightweight polystyrene foam pro¬ ducts.

The other important constituent of hydraulic paste is water. By definition, water is an essential component of the hydraulically settable materials within the scope of the present invention. The hydration reaction between the hydraulic binder and water yields reaction products which give the hydraulically settable materials the ability to set up and develop strength properties.

In most applications of the present invention, it is important that the water to cement ratio be carefully controlled in order to obtain a hydraulically settable mixture which after molding, extrusion, and/or calendaring is self-supporting in the green state. Nevertheless, the amount of water to be used is dependent upon a variety of factors, including the types and amounts of hydraulic binder, aggregates, fibrous materials, rheology-modifying agents, and other materials or additives within the hydraulically settable mixture, as well as the molding or forming process to be used, the specific product to be made, and its properties.

The preferred amount of added water within any given application is primarily dependent upon two key variables: (1) the amount of water which is required to react with and hydrate the binder; and (2) the amount of water required to

give the hydraulically settable mixture the necessary rheoxogical properties and workability.

In order for the green hydraulically settable mixture to have adequate workability, water must generally be included in quantities sufficient to wet each of the particular components and also to at least partially fill the interstices or voids between the particles (including, e.g., binder particles, aggregates, and fibrous materials) . If water soluble additives are included, enough water must be added to dissolve or otherwise react with the additive. In some cases, such as where a dispersant is added, work¬ ability can be increased while using less water.

The amount of water must be carefully balanced so that the hydraulically settable mixture is sufficiently work- able, while at the same time recognizing that lowering the water content increases both the green strength and the final strength of the hardened product. Of course, if less water is initially included within the mixture, less water must be removed in order to allow the product to harden. The appropriate rheology to meet these needs can be defined in terms of yield stress. The yield stress of the hydraulically settable mixture will usually be in the range from between about 2 kPa to about 5,000 Kpa, with the more preferred mixtures having a yield stress within a range from about 100 kPa to about 1,000 kPa, and the most preferred mixtures having a yield stress in the range from about 200 kPa to about 700 kPa. The desired level of yield stress can be (and may necessarily have to be) adjusted depending on the particular molding process being used to form the insulation barrier.

It may be desirable to initially include a relatively high water to cement ratio during or shortly after the sheet molding process. When more aggregates or other water absorbing additives are included, a higher water to hydraulically settable binder ratio is necessary in order to provide the same level of workability and available

water to hydrate the hydraulically settable binder. This is because a greater aggregate concentration provides a greater volume of interparticulate interstices or voids which must be filled by the water. Porous, lightweight aggregates can also internally absorb significant amounts of water due to their high void content.

Both of the competing goals of greater workability and high green strength can be accommodated by initially adding a relatively large amount of water and then driving off much of the water as steam during the molding process, usually by the use of heated rollers or drying tunnels.

Based on the foregoing qualifications, typically hydraulically settable mixtures within the scope of the present invention will have a water to hydraulically settable binder ratio within a range from about 0.1:1 to about 10:1, preferably about 0.3:1 to about 4:1,and most preferably from about 1:1 to about 3:1. The total amount of water remaining after drying the material to remove excess water will range up to about 20% by volume with respect to the dry, hardened hydraulically settable sheet

It should be understood that the hydraulic binder has an internal drying effect on the hydraulically settable mixture because binder particles chemically react with water and reduce the amount of free water within the interparticulate interstices. This internal drying effect can be enhanced by including faster reacting hydraulic binders such as gypsum hemihydrate along with slower reacting hydraulic cement.

According to a preferred embodiment of the present invention, it has been found desirable that the hydraulic binder and water be mixed in a high shear mixer such as that disclosed and claimed in U.S. Patent No. 4,225,247 entitled "Mixing and Agitating Device"; U.S. Patent No. 4,552,463 entitled "Method and Apparatus for Producing a Colloidal Mixture"; U.S. Patent No. 4,889,428 entitled "Rotary Mill"; U.S. Patent No. 4,944,595 entitled

"Apparatus for Producing Cement Building Materials"; and U.S. Patent No. 5,061,319 entitled "Process for Producing Cement Building Material." High shear mixers within the scope of these patents are available from E. Khashoggi Industries of Santa Barbara, California, the assignee of the present invention. The use of a high shear mixer results in a more homogeneous hydraulically settable mixture, which results in a product with higher strength. Furthermore, high shear mixers can be utilized to entrain significant amounts of air into the hydraulically settable mixture to create "foam-like" products.

C. Rheology-modifying Agents

The inclusion of a rheology-modifying agent acts to increase the plastic or cohesive nature of the hydraulic¬ ally settable mixture so that it behaves more like a moldable clay. The rheology-modifying agent tends to thicken the hydraulically settable mixture by increasing the yield stress of the mixture without greatly increasing the viscosity. Raising the yield stress in relation to the viscosity makes the material more plastic-like and moldable, while greatly increasing the subsequent form stability or green strength.

A variety of natural and synthetic organic rheology- modifying agents may be used that have a wide range of properties, including viscosity and solubility in water. In some cases, such as a highly foamed, lightweight insulating material there will be little or no hydraulic cement in the structural matrix. In this case, the rheology-modifying agent may be acting as the binder. The difference in solubility of the organic material can affect the degree in which the insulation material will break down in the presence of water.

Where it is desirable for the insulation barrier to more quickly break down when exposed to water, it may be preferable to use a rheology-modifying agent that is more

water soluble. Conversely, in order for the material to withstand prolonged exposure to water, it may be preferable to use a rheology-modifying agent that is less soluble in water. (Of course, using a higher content of hydraulically settable binder will yield an essentially insolubale insulation product.)

The various rheology-modifying agents contemplated by the present invention can be roughly organized into the following categories: (1) polysaccharides and derivatives thereof, (2) proteins and derivatives thereof, and (3) synthetic organic materials. Polysaccharide rheology- modifying agents can be further subdivided into (a) cellulose-based materials and derivatives thereof, (b) starch based materials and derivatives thereof, and (c) other polysaccharides. It is also within the scope of this invention to include various mixtures of cellulose-based materials, protein-based materials, starch-based materials, and synthetic organic plasticizers.

Suitable cellulose-based rheology-modifying agents include, for example, methylhydroxyethylcellulose, hydroxy- methylethylcellulose, carboxymethylcellulose, methyl- cellulose, ethylcellulose, hydroxyethylcellulose, hydroxy- ethylpropylcellulose, and the like. The entire range of possible permutations is enormous and cannot be listed here, but other cellulosic materials that have the same or similar properties as these would also work well.

Suitable starch based materials include, for example, amylopectin, amylose, sea gel, starch acetates, starch hydroxyethyl ethers, ionic starches, long-chain alkylstarches, dextrins, amine starches, phosphate starches, dialdehyde starches, and the like. Other natural polysaccharide based rheology-modifying agents include, for example, alginic acid, phycocolloids, agar, gum arabic, guar gum, locust bean gum, gum karaya, and gum tragacanth. Suitable protein-based rheology-modifying agents include, for example, Zein ^® (a prolamine derived from

corn) , collagen derivatives extracted from animal connective tissue such as gelatin and glue, and casein (the principal protein in cow milk) .

Suitable synthetic organic plasticizers include, for example, polyvinyl pyrrolidone, polyethylene glycol, polyvinyl alcohol, polyvinylmethyl ether, polyacrylic acids, polyacrylic acid salts, polyvinylacrylic acids, polyvinylacrylic acid salts, polyacrylimides, ethylene oxide polymers, polylactic acid, synthetic clay, and latex (which is a styrene-butadiene copolymer) . The rheology of polylactic acid is significantly modified by heat and could be used alone or in combination with any other of the foregoing rheology-modifying agents. Latex may be used to increase the resistance of the material to water. A currently preferred rheology-modifying agent is methylhydroxyethylcellulose, examples of which are Tylose ^® FL 15002 and Tylose ^® 4000, both of which are available from Hoechst Aktiengesellschaft of Frankfurt, Germany. Lower molecular weight rheology-modifying agents such as Tylose ^® 4000 can act to plasticize the mixture rather than thicken it, which helps during extrusion or rolling procedures.

More particularly, lower molecular weight rheology- modifying agents improve the internal flow of the hydraul¬ ically settable mixture during molding processes by lubricating the particles. This reduces the friction between the particles as well as between the mixture and the adjacent mold surfaces. Although a methylhydroxyethyl- cellulose rheology-modifying agent is preferred, almost any non-toxic rheology-modifying agent (including any listed above) which imparts the desired properties would be appropriate.

Another preferred rheology-modifying agent that can be used instead of, or in conjunction with, Tylose ^® is poly¬ ethylene glycol having a molecular weight of between about 20,000 and 35,000. Polyethylene glycol works more as a lubricant and adds a smoother consistency to the mixture.

For this reason, polyethylene glycol might be referred to more precisely as a "plasticizer". In addition, it gives the molded hydraulically settable material a smoother surface. Finally, polyethylene glycol can create a coating around soluble components of the mixture and thereby render the hardened product less water soluble.

Starch-based rheology-modifying agents are of particular interest within the scope of the present invention because of their comparatively low cost compared to cellulose-based rheology-modifying agents such as Tylose ^® . Although starches typically require heat and/or pressure in order to gelate, starches may by modified and prereacted so that they can gel at room temperature. The fact that starches, as well as many of the other rheology- modifying agents listed above, have a variety of solubili¬ ties, viscosities, and rheologies allows for the careful tailoring of the desired properties of a mix design so that it will conform to the particular manufacturing and performance criteria of a particular insulation barrier. In certain embodiments where a very lightweight, highly insulative material is desired, the alkylcellulose based rheology-modifying agent can act as the binder in the absence of a hydraulic binder. This type of material may be used where a dissolvable product is desired. The rheology-modifying agent within the hydraulically settable materials are generally included in an amount within a range from about 0.1% to about 30% by volume of the total solids of the hydraulically settable mixture, more preferably within a range from about 0.5% to about 15% by volume, and most preferably within a range from about 1% to about 10% by volume. If the rheology-modifying agent is acting as a binder it will be included in greater amounts.

D. Aggregates. it is within the scope of the present invention to include aggregates commonly used in the cement industry.

However, unlike many concrete products, the main purpose for the addition of aggregates to the compositions of the present invention is to make the hydraulically settable material more lightweight, rather than imparting significant strength to the material.

Examples of aggregates which can add a lightweight characteristic to the hydraulically settable mixture include perlite, vermiculite, glass beads, aerogels, sea- gels, calcined diatomaceous earth, xerogels, hollow plastic spheres, hollow glass spheres, calcium carbonate, synthetic materials (e.g., porous ceramic spheres, tabular alumina, etc.), cork, xonotlite (a crystalline calcium silicate gel), and lightweight expanded clays, sand, gravel, rock, limestone, sandstone, pumice, and other geological mater- ials. Of course, the choice of the aggregate will depend upon the weight, strength, toughness, texture, surface finish, insulation ability, and aesthetic qualities that might be desired in the resultant product.

In addition to conventional aggregates used in the cement industry, a wide variety of other aggregates, including fillers, strengtheners, including metals and metal alloys (such as stainless steel, calcium aluminate, iron, copper, silver, and gold) , balls or hollow spherical materials (such as glass, polymeric, and metals) , filings, pellets, powders (such as microsilica) , and fibers (such as graphite, silica, alumina, fiberglass, polymeric, organic fibers, and such other fibers typically used to prepare various types of composites) , may be combined with the hydraulically settable materials within the scope of the present invention. Even materials such as seeds, starches, gelatins, and agar-type materials can be incorporated as aggregates in the present invention.

Fibrous aggregates may be used in the present inven¬ tion primarily to add form stability to the mixture and to add strength, toughness, and flexibility to the resulting matrix, although certain fibrous aggregates may also impart

some level of insulation to the materials as well. There¬ fore, the term "aggregate" will refer to all other filler materials, which are nonfibrous, and whose function is mainly to impart rheological, textural and insulative properties to the materials.

It is also within the scope of the present invention to include set hydraulic cement compositions as examples of aggregates. Examples of hydraulic cement compositions include used insulation barriers of the present invention, which can be recycled and used as aggregates in the hydraulic cement compositions of new insulation barriers within the scope of the present invention. Moreover, due to more restrictive environmental legislation, many ready- mix concrete suppliers are often obligated to find adequate means of handling, recycling, and marketing their waste solids. The present invention sets forth a use for such waste solids.

For many uses, it is preferable to include a plurality of differently sized and graded aggregates capable of filling interstices between the aggregates and the hydraulic binder so that less water is necessary and, hence, greater strength can be achieved. In such cases, the differently sized aggregates would typically have particle sizes in the range from as small as about 0.5μm to as large as about 2 inches. (Of course, the thickness of the insulation barrier or structural component will dictate the appropriate size of the aggregates to be used.) It is within the skill of one in the art to know generally which aggregates are to be used to achieve the desired characteristics in the final insulating barrier.

For example, where very thick-walled insulation is desired, very large aggregates can be used. Conversely, where a thin-walled structure is involved, usually in the case of the higher density support layer, it is preferable to use much smaller aggregates. As a general rule, the

aggregates should not have a diameter of more than one- fourth the wall thickness of the material involved.

In certain preferred embodiments of the present invention, it is desirable to maximize the amount of the aggregates in the hydraulically settable mixture in order to maximize the properties and characteristics of the aggregates (such as their lightweight or insulative qualities) . In order to maximize the amount of the aggregates, the use of particle packing techniques is desirable. A detailed discussion of particle packing can be found in the following article co-authored by one of the inventors of the present invention: Johansen, V. & Ander¬ sen, P.J., "Particle Packing and Concrete Properties," Materials Science of Concrete II at 111-147, The American Ceramic Society (1991) . Further information is available in the Doctoral Dissertation of Andersen, P.J., "Control and Monitoring of Concrete Production — A Study of Particle Packing and Rheology," The Danish Academy of Technical Sciences. The advantages of such packing of the aggregates can be further understood by reference to the examples which follow in which hollow glass balls of varying sizes are mixed in order to maximize the amount of the glass balls in the hydraulically settable mixture.

Where strength is less important and high insulation is the overriding goal for a given application, it may be preferable to incorporate into the hydraulically settable matrix an aggregate which has a low thermal conductivity, or "k-factor" (defined as W/m*K) , which is roughly the reciprocal of the expression commonly used in the United States for thermal resistance, or "R-factor," which is generally defined as having the units hr«ft "F/BTU. The term "R-factor" is most commonly used in the United States to describe the overall thermal resistance of a given material without regard to the thickness of the material. However, for purposes of comparison, it is common to normalize the R-factor to describe thermal resistance per

inch of thickness of the material in question, or hr«ft ² °F/BTU«in.

For purposes of this application, the insulation ability of a given material will hereinafter be expressed only in terms of the IUPAC method of describing thermal conductivity, or k-factor. The conversion of thermal resistance expressed in British units (hr«ft 2°F/BTU«ιn) to IUPAC units can be performed by multiplying the normalized R-factor by 6.9335, and then taking the reciprocal of the product.

Preferred lightweight aggregates include expanded or exfoliated vermiculite, perlite, calcined diatomaceous earth, aerogels, xerogels, hollow glass spheres, xonotlite, and hollow plastic spheres — all of which tend to contain large amounts of incorporated interstitial space. This interstitial space, which consists of microscopically small fixed air spaces, greatly lowers the k-factor of these agg¬ regates, thereby greatly increasing the insulation capabil¬ ity of the material involved. However, this list is in no way intended to be exhaustive, these aggregates being chosen because of their low cost and ready availability. Nevertheless, any aggregate with a low k-factor, which is able to impart sufficient insulation properties into the insulation barrier, is within the purview of the present invention.

The amount of the aggregate will vary depending upon the particular application or purpose, from no added aggregate up to about 90% by volume of the total solids of the hydraulically settable mixture. Where high insulation is desired, the amount of aggregates will preferably be within a range from about 5% to about 70% by volume, and most preferably from about 20% to about 50% by volume of the mixture. Further, it will be appreciated that for any given product, certain of these aggregates may be preferable while others may not be usable.

E. Fibrous Materials.

As used in the specification and appended claims, the terms "fibers" and "fibrous materials" include both inorganic fibers and organic fibers. Fibers are a particular kind of aggregate that may be added to the hydraulically settable mixture to increase the cohesion, elongation ability, deflection ability, toughness, fracture energy, and flexural, tensile, and, on occasion, even compressive strengths. Fibrous materials reduce the likelihood that the hydraulically settable matrix will shatter when a strong cross-sectional force is applied. The concept of adding fibers is analogous to reinforcing concrete with steel bars or wire, except that the reinforcement is on a "micro" rather than a "macro" level.

In evaluating potential fibers for use in the materials used to form an insulation barrier, important characteristics to consider are: the physical properties of the fibers (e.g., length and diameter, tensile strength, and wetability/dispersability) , cost, reliability of supply (quantity and consistency) , and the relative level of contaminants in the fiber (e.g., lignin, pectin, fats, waxes, etc.) .

Examples of fibers that may be utilized singly or in a variety of mixtures include glass fibers, silica fibers, ceramic fibers (such as alumina, silica nitride, silica carbide, and graphite), rock wool, metal fibers, carbon fibers, and synthetic polymer fibers such as polypropylene, polyethylene, nylon, or rayon fibers. Fibers extracted from plant leaves and stems may be used, as well as any naturally occurring fiber comprised of cellulose. Such fibers are available from wood and paper pulp (e.g., wood flour or saw dust) , wood fibers (both hardwood or softwood such as southern pine) , recycled paper, cotton, cotton linters, abaca (Manila hemp), sisal, jute, sunn hemp, flax, and bagasse. Any equivalent fiber, however, which imparts

strength and flexibility is also within the scope of the present invention.

Fibers or other aggregates may also be formed in the hydraulically settable sheets as inorganic precipitates in situ. Such precipitates can be in the form of polymerized silicates, alumino-silicate gels, and the like.

Preferred fibers include glass fibers, cellulose fibers (from unbleached kraft pulp) , abaca fibers (extracted from a Philippine hemp plant related to the banana), bagasse, wood fibers, ceramic fibers, and cotton. When glass fibers are used they are preferably pretreated to be alkali resistant. Glass fibers such as Ce fill ^® are available from Pilkington Corp. in England. Abaca fibers are available from Isarog Inc. in the Philippines. These fibers are used due to their low cost, high strength, and ready availability. Nevertheless, any equivalent fiber which imparts strength, as well as flexibility if needed, is certainly within the scope of the present invention. The only limiting criteria is that the fibers impart the desired properties without posing significant health hazards to manufacturers, installers, or end users (e.g.. home or office dwellers) of the insulation material.

The fibers used to make the hydraulically settable sheets used in the present invention preferably have a high length to width ratio (or "aspect ratio") because longer, narrower fibers can impart more strength to the matrix without significantly adding bulk and mass to the mixture. The fibers should have an aspect ratio of at least about 10:1, preferably at least about 100:1. An aspect ratio of between about 200:1 to 300:1 is most preferred.

Preferred fibers should also have a length that is several times the diameter of the hydraulically settable binder particles. Fibers having a length that is at least about twice the average diameter of the hydraulic binder particles will work, while fibers having a length at least about 10 times the average diameter of the hydraulic binder

particles is preferred, with at least about 100 times being more preferred, and even about 1000 times being very useful. High fiber length to binder particle ratios can be achieved by either increasing the absolute length of the added fibers or, alternatively, by using a more finely milled binder.

It will be appreciated, however, that the strength of the fiber is a very important feature in determining the amount of the fiber to be used. The stronger the tensile strength of the fiber, the less the amount that must be used to obtain the same level of tensile strength in the resulting product. Of course, while some fibers have a high tensile strength, other types of fibers with a lower tensile strength may be more elastic. Hence, a combination of two or more fibers may be desirable in order to obtain a resulting product that maximizes multiple characteris¬ tics, such as high tensile strength and high elasticity.

In addition, the properties imparted to a hardened hydraulically settable matrix by the fibers can be increased by unidirectionally or bidirectionally orienting the fibers within the hydraulically settable matrix. Depending on the shape of the extruder die head, the extrusion process itself will tend to orient the fibers in the "Y" (or longitudinal) direction. The rolling process, during which a sheet may also be elongated, further orients the fibers in the "Y" direction.

In addition, by using a pair of rollers having differ¬ ent orientations in the "Z" direction (or normal to the surface of the sheet) , such as by using a flat roller paired with a conical roller, a percentage of the fibers can be oriented in the "X" (or width-wise) direction. This is thought to occur because the conical roller can widen the sheet in the "X" direction. In this way a sheet having bidirectionally oriented fibers, can be manufactured. As a result, the desired strength characteristics can be engineered into the resultant sheet.

The amount of fibers added to the hydraulically settable matrix will vary depending upon the desired properties of the final product, with strength, toughness, flexibility, and cost being the principal criteria for determining the amount of fiber to be added in any mix design. In most cases, fibers will be added in an amount within the range from about 0.2% to about 50% by volume of the total solids of the hydraulically settable mixture, ffi both the "foam-like" and the "clay-like" insulation products or constituents contemplated by the present invention, the amount of fibers will generally be within the range from about 0.5% to about 10% by volume, and most preferably, within the range from about 1% to about 6% by volume.

F. Air Voids.

In those applications where insulation and not strength is the overriding factor (as with insulation barriers where structural support is not important, or where the weaker, more insulating material is reinforced with a layer of stronger hydraulically settable material) it may be desirable to incorporate into the hydraulically settable matrix air pockets or voids in addition to, or in place of, aggregates in order to increase the insulative properties of the final product. The incorporation of air voids into the hydraulically settable mixture is carefully calculated to impart the requisite insulation characteris¬ tics without unduly degrading the strength of the insulation barrier (or portion thereof) to the point of nonutility. (Generally, however, where insulation is not an important feature of a particular product, or portion thereof, it is desirable to minimize any air voids in order to maximize strength and minimize weight and volume.)

In certain embodiments, finely dispersed air voids can be introduced by high shear, high speed mixing of the hydraulic paste, with a foaming or stabilizing agent added

to the mixture to aid in the incorporation of air voids. The high shear, high energy mixers discussed above are particularly adept in achieving this desired goal. Suitable foaming and stabilizing agents include commonly used surfactants and materials. Currently preferred embodiments of such surfactants include a polypeptide alkylene polyol (Mearlcrete ^® Foam Liquid) and a synthetic liquid anionic biodegradable solution (Mearlcel 3532 ^® ), both available from the Mearl Corporation in New Jersey. Another foaming and stabilizing agent is vinsol resin.

In this process, a gas can also be injected into the hydraulic paste such that it is substantially uniformly incorporated by the high energy mixer and then stabilized by the foaming and stabilizing agents. A variety of different gases can be utilized; many inexpensive gases suitable for use in the hydraulic paste are available. One currently preferred gas is carbon dioxide since it can react with the components of the hydraulically settable binder to increase both the form stability as well as the foam stability of the hydraulically settable mixture through a false setting mechanism. (The incorporation of carbon dioxide does not, however, appreciably increase the rate of hydration or setting.)

The early false setting and foam stability is thought to result from the reaction of C0 ₂ with the hydroxide ions within the hydraulically settable mixture to form carbonate ions. Achieving high foam stability of the air voids within the hydraulically settable mixture is often crucial to maximizing both the strength and insulation properties of the cured hydraulically settable insulation material. Foam stability helps maintain over time the dispersion, and prevents the agglomeration, of the air voids within the unhardened hydraulically settable mixture. Failure to prevent the coalescence of the air voids actually decreases the insulation effect, while decreasing the strength, of the cured hydraulically settable mixture.

This is because larger air voids act to create significantly larger discontinuities within the hydraulic¬ ally settable structural matrix arid, hence, weaker links within the matrix which are more easily fractured. At the same time, the creation of larger, more agglomerated air pockets necessarily decreases the dispersion of the air void system within the matrix and increases the number and volume of continuous hydraulically settable "bridges" throughout the foamed material, which bridges act as more effective conduits of heat. Hence, less finely dispersed air results in greater heat conductivity of the hydraulically settable material.

Maintaining the highest possible dispersion of air voids, and thus maintaining the greatest number and smallest size of air voids, is optimal and can be achieved by increasing the foam stability. As stated above, one such method is through the addition of carbon dioxide. Factors such as raising the pH, increasing the concentra¬ tion of soluble alkali metals such as sodium or potassium, adding a stabilizing agent such as a polysaccharide rheology-modifying agent, and carefully adjusting the concentrations of surfactant and water within the hydraul¬ ically settable mixture all increase the foam stability. Adjusting the concentrations of water and surfactant affects the propensity of air to be entrained in an emulsion-like fashion within the hydraulically settable mixture.

On the other hand, raising the pH and/or increasing the concentration of alkali metals increases the rate and the amount of carbon dioxide dissolution within the aqueous phase of the hydraulically settable mixture. This is because both increase the solubility of carbonate ions, which might otherwise form insoluble precipitates with calcium ions present in all hydraulic cements. This process of incorporating gas into the hydraulically settable mixture is generally suitable for

processes where the mixture is relatively nonviscous, such as in injection molding where the hydraulic paste is injected through small holes, or where a foamed hydraulically settable insulation product is injected between structural walls or simply poured into molds.

During the process of molding and/or curing the hydraulically settable mixture, it is often desirable to heat up the mixture in order to control the air void system and to aid in stabilizing the mixture form in the green state (immediately after molding) . Heating also aids in rapidly removing significant amounts of the water from the hydraulically settable mixture.

If a gas has been incorporated into the hydraulically settable mixture, heating the mixture to 250°C will result (according to the gas-volume equation) in the gas increas¬ ing its volume by about 85%. When heating is appropriate, it has been found desirable for the heating to be within a range from about 50°C to about 250°C. More importantly, if properly controlled, heating will not result in the cracking of the structural matrix, or yield imperfections in the surface texture, of the insulation barrier.

Another foaming agent is a mixture of citric acid and bicarbonate, or bicarbonate that has been processed into small granules or particles and coated with wax, starch, or water soluble coatings. This can be used in void formation two ways: (1) to react with water and form C0 ₂ gas in order to create a cellular foam structure within the inorganic¬ ally filled matrix; or (2) to pack the particles as part of the matrix and after hardening the matrix remove the foam particles by heating the product above 180°C, which causes an endothermic decomposition of the particles, leaving behind a well controlled cellular lightweight structure.

In other applications, where viscosity of the hydraulically settable mixture is high, such as in certain molding processes, it is much more difficult to obtain adequate numbers of air voids through high shear mixing.

In this case, air voids are alternatively introduced into the hydraulic paste by adding an easily oxidized metal, such as aluminum, magnesium, zinc, or tin. To enhance the effect of the metal, it is preferable to add a base (such as sodium hydroxide) to the hydraulically settable mixture, which preferably raises the pH to between about 13-14 and causes these metals to undergo oxidation. At the same time, some of the ions (such as hydrogen ions) present in the water are concomitantly reduced to a gaseous product (such as hydrogen gas) , which then becomes dispersed throughout the hydraulic paste in the form of microscopic bubbles. Aluminum and zinc are the preferred metals of choice because of their relatively low cost compared to other metals which undergo oxidation when exposed to basic conditions. Nevertheless, it should be understood that any metal that is easily oxidized when exposed to highly alkaline conditions would work equally well and would be within the scope of the present invention.

Finally, air voids can be introduced into the hydraulically settable mixture during the molding process by adding a blowing agent to the mixture, which will expand when heat is added to the mixture. Blowing agents typically consist of a low boiling point liquid and finely divided calcium carbonate (chalk) . The chalk and blowing agent are uniformly mixed into the hydraulically settable mixture. The liquid blowing agent penetrates into the pores of the individual chalk particles, which act as points from which the blowing agent can then be atomized upon thermal expansion of the blowing agent. During the molding or extrusion process, the mixture is heated while at same time it is compressed. While the heat would normally cause the blowing agent to vaporize, the increase in pressure temporarily prevents the agent from vaporizing, thereby temporarily creating an equilibrium. When the pressure is released after the molding or extrusion of the material the blowing agent

vaporizes, thereby expanding or "blowing" the hydraulically settable material. The hydraulically settable material eventually hardens with very finely dispersed voids throughout the structural matrix. Water can also act as a blowing agent as long as the mixture is heated above the boiling point of water and kept under pressure.

Air voids increase the insulative properties of the insulation barriers and also greatly decrease the bulk specific gravity, and hence the weight, of the final product. This reduces the overall mass of the resultant product, which reduces the amount of material that is required for the manufacture of the insulation barriers.

G. Dispersants The term "dispersant" is used hereinafter to refer to the class of materials that can be added to reduce the viscosity and yield stress of the hydraulically settable mixture. A more detailed description of the use of dispersants may be found in the Master's Thesis of Andersen, P.J. , "Effects of Organic Superplasticizing Admixtures and Their Components on Zeta Potential and Related Properties of Cement Materials" (1987) .

Dispersants generally work by being adsorbed onto the surface of the hydraulic binder particles and/or into the near colloid double layer of the binder particles. This creates a negative charge around the surfaces of particles, causing them to repel each other. This repulsion of the particles adds "lubrication" by reducing the "friction" or attractive forces that would otherwise cause the particles to have greater interaction. Because of this, less water can be added initially while maintaining the workability of the hydraulically settable mixture.

Greatly reducing the viscosity and yield stress may be desirable where clay-like properties, cohesiveness, and/or form stability are less important. Adding a dispersant aids in keeping the hydraulically settable mixture workable

even when very little water is added, particularly where there is a "deficiency" of water. Hence, adding a dispersant allows for an even greater deficiency of water, although the molded sheet may have somewhat less form stability if too much dispersant is used. Nevertheless, including less water initially will theoretically yield a stronger final cured sheet according to the Feret Equation. Whether or not there is a deficiency of water is both a function of the stoichiometric amount of water required to hydrate the binder and the amount of water needed to occupy the interstices between the particles in the hydraulically settable mixture, including the hydraulic binder particles themselves and the particles within the aggregate material and/or fibrous material. Improved particle packing reduces the volume of the interstices between the hydraulic binder and aggregate particles and, hence, the amount of water necessary to fully hydrate the binder and maintain the workability of the hydraulically settable mixture by filling the interstitial space.

However, due to the nature of the coating mechanism of the dispersant, the order in which the dispersant is added to the mixture is often critical. If a flocculating/ gelating agent such as Tylose ^® is added, the dispersant should be added first and the flocculating agent second. Otherwise, the dispersant may not be able to become adsorbed on the surface of the hydraulic binder particles as the Tylose ^® will be irreversibly adsorbed onto the surface of the particles, thereby bridging them together rather than causing them to repel each other. A preferred dispersant is sulfonated naphthalene- formaldehyde condensate, an example of which is WRDA 19, which is available from W.R. Grace, Inc. located in Baltimore, Maryland. Other dispersants which would work well include sulfonated melamine-formaldehyde condensate, lignosulfonate, and acrylic acid.

The amount of added dispersant will generally range up to about 3% by volume of the total solids of the hydraulically settable mixture, more preferably within the range of between about 0.1% to about 2% by volume, and most preferably within the range of between about 0.2% to about 1% by volume. However, it is important not to include too much dispersant as it tends to retard the hydration reactions between, e.g., hydraulic cement and water. Adding too much dispersant can, in fact, prevent hydration, thereby destroying the binding ability of the cement paste altogether.

The dispersants contemplated within the present invention have sometimes been referred to in the concrete industry as "superplasticizers." In order to better distinguish dispersants from rheology-modifying agents, which often act as plasticizers, the term "superplasticizer" will not be used in this specification.

H. Coatings.

For commercial purposes, it is often desirable that the surfaces of the insulation barriers be capable of receiving ink or other printing indicia. Hydraulically settable products such as those disclosed herein are particularly well suited for such a use. Furthermore, it is within the scope of the present invention to coat the insulation barriers with sealing materials and other coatings, many of which would increase the ability to put print on the insulation barriers.

One such coating is calcium carbonate, which is well known in the printing industry as being an effective surface on which indicia can be placed. Hence, most of the presently known prior art methods of printing or placing indicia on this coating are applicable in connection with the present invention. Not only can decals be placed on the surface, but the porosity of the hydraulically settable surface itself is such that it will properly absorb ink

without running. Even multiple color or multiple layer printing is relatively easily achieved.

Other coatings which might be appropriate include acrylics, polyacrylates, polyurethanes, melamines, polyethylene, synthetic polymers, waxes (such as bees wax or petroleum based wax) . In some cases, it may be preferable for the coating to be elastomeric, deformable, waterproof, or a combination thereof.

The coatings may be applied to hydraulically settable materials using any coating means known in the art. Sheets can be coated using methods known in the paper art. Coatings may be applied by spraying the sheet with any of the above coating materials, or it may be advantageous to apply the coating by dipping the sheet into a vat contain- ing an appropriate coating material. In the case where a coating material is sprayed onto the surface of a sheet, the coating material may be spread or smoothed by means of a doctor blade which is held a particular distance above the sheet, or which rides directly on the sheet surface.

In addition, coatings may be coextruded along with the sheet in order to integrate the coating process with the extrusion process. In other cases, the coating can be applied to the surface of the sheet by means of a gravure roller, often in conjunction with a doctor blade in order to smooth or adjust the thickness of the coating.

I. Densities of the Materials.

The densities of the resulting hydraulically settable insulation barriers manufactured according to the present invention will depend on the density of the lightweight insulating material together with the density of the hydraulically settable structural layer(s) . Normally, very lightweight insulating materials such as aerogel have a density between about 0.01 g/cm 3, and 0.3 g/cm3 and sea gel between about 0.01 g/cm and 0.25 g/cm .

The density of a hydraulically settable layer will depend on amount of entrained air and/or the amount of included lightweight aggregate within the hydraulically settable mixture. The density of the hydraulically settable material will generally inversely correlate with its ability to insulate. Depending on the type and amount of the added aggregate, the amount of entrained air, and/or the type of material within a laminate structure, the densities of the insulation materials of the present invention will generally be within a range from about 0.1 g/cm to about 2 g/cm . The density will be preferably less than about 2 g/cm , more preferably less than about 1 g/cm , and most preferably less than about 0.5 g/cm .

II. Specific Applications of the Materials into Insulation Barriers.

It is important that the basic structural component of the insulation barriers of the present invention be the hydraulically settable matrix. Within the basic matrix of hydraulic binder and water are incorporated other components which add additional characteristics and properties, such as fibers, aggregates, air voids, rheology-modifying agents, etc.

Hydraulically settable materials of the present invention which have little or no entrained air and/or lightweight aggregates are less insulative than their lighter weight counterparts, but have superior strength properties. In one preferred embodiment of the present invention, it is desirable to sandwich or otherwise join together a hydraulically settable layer for structural support with more highly insulative hydraulically settable or nonhydraulically settable materials to form a laminate structure in order to maximize both the insulative ability and strength of the resulting insulation barrier. Besides the hydraulically settable matrix, other materials can be used to give strength to the insulating

laminate, including plastic, metal foil, paper, fiber glass fabric, wood, wood pulp, or any other appropriate supporting material known in the art.

The low density, highly foamed, highly insulative layer may include a highly foamed hydraulically settable material and/or a highly insulative nonhydraulically settable material. One example of the latter is a foamed product formed from a mixture containing an aggregate, water, and a nonhydraulically settable organic binder such as any of the rheology-modifying agents listed above. A preferred binder is Tylose ^® , or methylhydroxyethylcellu- lose. Although Tylose ^® is often used as a rheology- modifying agent in many of the embodiments of the present invention, it has been found to be an adequate binder in cases where high structural strength is not required.

Other suitable organic polymer binders include most of the rheology-modifying agents listed above including methylhydroxyethylcellulose, hydroxymethylethylcellulose, carboxymethylcellulose, methylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxyethylpropylcellulose, amylopectin, amylose, sea gel, starch acetates, starch hydroxyethyl ethers, ionic starches, long-chain alkylstar- ches, dextrins, amine starches, phosphate starches, dialdehyde starches, alginic acid, phycocolloids, agar, gum arabic, guar gum, locust bean gum, gum karaya, gum tragacanth, Zein ^® , collagen derivatives extracted from animal connective tissue such as gelatin and glue, casein, latex, polyvinyl pyrrolidone, polyethylene glycol, poly¬ vinyl alcohol, polyvinylmethyl ether, polyacrylic acids, polyacrylic acid salts, polyvinylacrylic acids, polyvinyl¬ acrylic acid salts, polyacrylimides, and ethylene oxide polymers.

A. Purposes of Components in Hydraulically Settable Mixtures.

As discussed above, fibers are added to impart strength and some insulation to the hydraulically settable insulation barrier. Aggregates are employed to increase the barrier's ability to insulate and to decrease the bulk specific gravity of the hydraulically settable mixture. Discontinuous, nonagglomerated air voids can be mechanic¬ ally or chemically introduced into the hydraulically settable mixture, thereby decreasing the bulk specific gravity, and increasing the insulating ability, of the final product.

Because this invention is directed towards materials which will be handled by installers and exposed to end users somewhat, they will preferably not contain hazardous substances, as do other prior art insulation materials such as asbestos, polyisocyanate foam, or UFFI foam. The insulation barriers of the present invention are typically comprised of a hydraulic binder such as cement, aggregates, one or more fibers, and a rheology-modifying agent. Appropriate hydraulic binders that can be used herein contain differing quantities of the following compounds before hydration: CaO, Si0 ₂ , Al ₂ 0 ₃ , Fe ₂ 0 ₃ , MgO, and S0 ₃ . Upon hydration, these react to form very stable, unreactive rocklike compounds essentially harmless to humans and animals.

The fibers used herein are preferably natural fibers made from cellulose or glass fibers. Either type of fiber is harmless to humans and animals. The aggregates used in this invention are preferably small, lightweight rock-like substances or hollow glass spheres which contain a high percentage of air voids. Like cement, these are also very stable, unreactive, and harmless to humans and animals.

Aggregates are added mainly to add insulation ability to the final hydraulically settable product (in the case of lightweight aggregates) , although they may also be added to

increase the strength of the final product (in the case of stronger, more dense aggregates) . The size of the aggregates is controlled so that they are preferably about one fourth (or smaller) of the thickness of the insulation barrier to be manufactured. As mentioned above, it is frequently desirable to employ particle packing techniques in order to maximize the desirable properties and charac¬ teristics of the aggregates into the hydraulically settable mixture. Simply stated, these techniques maximize the amount of the aggregates in the matrix and minimize the space (and hence the discontinuities) between the aggre¬ gates. Thus, the strength and other properties of the total hydraulically settable matrix becomes dependent upon that of the aggregates and the hydraulic binder.

The discontinuous phase of nonagglomerated air voids greatly increases the insulative ability of the hydraulically settable material. Maximization of the insulating effect of the air voids, as well as maximizing the strength of the foamed material, is achieved by initially creating the smallest and most well-dispersed voids possible. It is equally important to stabilize the foamed mixture in order to maintain the fine, even dispersion of the air voids using the methods described above. In any event, the air voids that may be incorporated within the hydraulically settable structural matrix will contain none of the harmful substances that can diffuse out of many foamed insulation products in use today. The voids within polystyrene foam insulation often contains harmful CFC's, while UFFI contains formaldehyde. Typically, the hydraulically settable insulation barriers of the present invention will have a compressive strength to bulk density ratio in a range from about 1 MPa _' g/cm ³ to about 300 MPa*g/cm , more preferably in a range from about 2 MPa•g/cm to about 50 MPa*g/cm , and most preferably in a range from about 3 MPa*g/cm to about 20 MPa*g/cm .

A significant advantage of the hydraulically settable insulation barriers manufactured according to the present invention is that they do not release dangerous or ozone depleting chemicals. If disposed of into the earth they will not persist as will synthetic materials, which must biodegrade (often after many years or decades) before becoming environmentally neutral. Instead, waste insula¬ tion barriers of the present invention are essentially composed of the same materials already found in the earth. Under the weight and pressure of typical landfills such insulation barriers will crumble and break down into an environmentally neutral powder that is the same as, or at least compatible with, the dirt and rock already found within the earth. Furthermore, hydraulically settable insulation barriers described herein are fully recyclable with a minimum amount of energy and effort. Unlike petroleum- based insulation products which require a substantial amount of processing in order to restore them to a suitable state as raw starting materials, hydraulically settable insulation barriers can be ground up and recycled by merely reincorporating the grindings into new insulation barriers as an aggregate component within a virgin hydraulic paste. This quality of containing both a hydraulically settable binder, along with an aggregate is a further departure from prior art insulation materials which typically consist of a uniform material such as polystyrene, glass fibers, or urea-formaldehyde wherein the strength and insulating properties are derived from the same components.

B. The Processing Technigues and Conditions.

The combination of hydraulic binders, aggregates, air voids, and fibers results in a composition that can be formed into relatively thin, strong sheets or walls; they can be formed into very thick, porous materials, with extremely high insulation capabilities; or they may contain

a combination of the two. Consequently, the insulation barriers of the present invention can be made into a variety of shapes and thicknesses and can take the place of any presently known insulation material. In addition, they can be formed into relatively thin sheets and used in place of conventional wallboard.

The advantage of a hydraulically settable wallboard over gypsum board is that the former is simultaneously much more lightweight, insulative, yet has comparable and even superior strength depending upon its composition. Indeed, the combination of using a more insulating wallboard, along with insulation having the same qualities of presently known insulation methods, results in a better insulated building. in order for the material to exhibit the best properties of high tensile and flexural strength and insulation, the fibers can be aligned or stacked according to the present invention, instead of being randomly dispersed, throughout the hydraulic binder. It is usually preferable for the fibers to be laid out in a plane that is parallel to either of the two surfaces of the hydraulically settable sheet or insulation barrier wall.

Such alignment of fibers is preferably achieved either by extrusion or rollering. These processes result in near zero porosity in terms of large, continuous and unwanted air pockets which usually occur during normal cement manufacture. This greatly increases the strength of the hydraulically settable material and reduces the tendency of splitting or tearing when the insulation barrier is exposed to external mechanical forces.

The undesirable discontinuities and voids in typical cementitious products should not be confused with the finely dispersed air (or other gas) voids that may be intentionally introduced by the direct introduction of gas, the use of a high energy mixer, or the addition of reactive metals. Undesired voids or discontinuities are large and

randomly dispersed, and offer little in terms of added insulative properties, while at the same time greatly reducing the consistency and strength of the cement matrix. In contrast, the intentionally introduced gas bubbles or voids are generally very small, uniformly dispersed throughout the hydraulically settable mixture, and able to insulate without substantially reducing the strength of the underlying structural matrix.

Insulation barriers incorporating large amounts of gas bubbles or voids and made by this method exhibit the insulating properties similar to those of styrofoam insulating materials. For example, hydraulically settable insulation barriers made according to the present invention have been shown to provide excellent insulation. For instance, the highly foamed, ultra lightweight materials have demonstrated k-factors as low as 0.0212 W/m*K. Most of the laminates having an insulating layer sandwiched between two structural sheets had k-factors of between about 0.036 W/m*K to 0.0515 W/m*K. Even the structural sheets themselves had k-factors of about 0.22 W/m*K.

By altering the quantities of the hydraulically settable binder, water, aggregates, fibers, and rheology- modifying agent, it is possible to control the rheology of the hydraulically settable mixture. For example, in the case of direct molding methods or extrusion, where immediate form stability is very important, it is prefer¬ able to start with a hydraulically settable mixture which has high yield stress so that it can maintain its shape. On the other hand, in the case of, for example, filling voids between walls, or simply pouring the hydraulically settable mixture into molds, the mixture will usually have a lower yield stress and viscosity. Because insulation barriers formed by these methods solidify within a mold or existing building structure it is not necessary that these hydraulically settable mixtures become form stable as quickly as in other types of molding processes.

Nevertheless, even less viscous hydraulically settable mixtures must be able to become form stable very rapidly after being placed in the mold in order for the process to be economical. Generally, the longer the product remains in the mold, the higher the cost of manufacturing.

Nevertheless, whether a viscous or nonviscous hydraulically settable mixture is required, it is desirable to use a minimal amount of water. This is because it is important to control the capillary action of the water in the hydraulically settable mixture, as this is a cause of the stickiness of the mixture, which in turn can cause problems in demolding the mixture from the mold. Hence, the capillary action of the water is preferably reduced to allow for quick release of the hydraulically settable mixture from the mold. Using less water further results in a stronger cured or hardened material. However, greater amounts of water can be used in the case of heating, which quickly drives off excess water and creates a steam layer between the hydraulically settable mixture and the mold.

As discussed above, there are a variety of suitable rheology-modifying agents. The use of a rheology-modifying agent allows for the use of less water while allowing the mixture to deform and flow when subjected to forces associated with the molding process. The rheology- modifying agent adds form stability so that the molded hydraulically settable product will maintain its shape without external support and resist forces involved in the subsequent handling of the material.

1. The "Molding" Process.

During the mixing of the hydraulic paste, it is often important to obtain flocculation or gelation of the mixture. From a macroscopic perspective, flocculation gives the hydraulically settable mixture a more plastic- like characteristic.

For purposes of simplicity, the term "molding," as used in this specification and the appended claims, is intended to include a variety of molding, casting, and extrusion processes discussed herein, or that are well known in the art with respect to materials such as clays, ceramics, plasters, and plastics, as well as the process of releasing (or "demolding") the hydraulically settable product from the mold. The term "molding" also includes additional processes that might occur while the hydraul¬ ically settable mixture is in the mold such as, e.g., heating the hydraulically settable mixture to expand the mixture in the mold, increase the reaction of any added metal, and create a steam barrier to prevent sticking.

In order for the hydraulically settable mixtures of certain embodiments (usually the clay-like structural portion) to be effectively molded, it is often desirable that the mixture be form stable in the green state; that is to say, the molded product should rapidly (preferably in a matter of hours, minutes, or even seconds) be able to support its weight without external support. Further, the product must harden sufficiently so that it can be quickly ejected from the mold without sustaining significant damage. Otherwise, the cost and difficulty of molding may make the process uneconomical or unfeasible. In addition, the surface of the molded hydraulically settable article may not be overly tacky, as that would make the demolding process impossible and make the handling and stacking of the molded articles more difficult. Heating the mold (and, therefore the surface of the molded product) causes the surface to harden more quickly and reduces its tackiness.

There are several modifications to conventional molding processes which are preferably employed in order to ease the manufacturing process. For example, it is frequently desirable to treat the mold with a releasing agent in order to prevent sticking. Suitable releasing agents include silicon oil, Teflon ^® , Deleron ^® , and UHW ^® .

Preferably, the mold itself will be made of polished steel coated with nickel, chromium, Teflon ^® , or Deleron ^® . Similar effects can be achieved by heating the mold to form a steam barrier. If a gas has been incorporated into the hydraulically settable mixture, heating that mixture to 250°C will result (according to the gas-volume equation) in the gas increasing its volume by about 85%. When heating is appropriate, it has been found desirable for that heating to be in the range from about 50°C to about 250°C. More importantly, when properly controlled, heating will not result in the formulation of cracks or other imperfections in the insulation barrier.

In fact, the process of adding gas bubbles to the hydraulically settable mixture during the molding process can help the molded product to quickly gain stability. From the foregoing disclosure, it will be apparent that this can be accomplished by the addition of a gas- generating material, such as an easily oxidized metal like zinc or aluminum, and that the gas generating process can be accelerated by the addition of a base and/or heat.

2. The Curing Process. Terms such as "cure" or "curing" shall refer to the process whereby a hydraulically settable mixture achieves a substantial portion of its total strength, generally through the process known as "hydration," but also due to simply removing a significant portion of the water within the hydraulically settable mixture such as by heating. Nevertheless, even where water is driven off by heating, even to the point where the molded product attains a certain level of stiffness, the hydraulic binder still undergoes normal hydration albeit at an elevated rate catalyzed by the addition of heat. Even before the molded hydraulically settable compositions obtain significant final strength through the

hydration process they must also rapidly gain sufficient strength while still in the green state so that they can be mass-produced and handled within reasonable time periods. This is in sharp contrast to typical cement products, which take hours, even days, to reach even minimal strength. Thus, high green strength is often essential for the molded product to be quickly removed from the mold, further pro¬ cessed as necessary, stacked, and packaged.

While no significant processing condition is necessarily modified for curing the products within the scope of the present invention, many of the features discussed above (e.g., inter alia , the use of a rheology- modifying agent, controlling the capillary action of water, the introduction of aid voids throughout the hydraulically settable mixture, the use of heat, and creating form stability in the green state) are important for the hydraulically settable products to achieve strength quickly and properly cure.

However, as stated above, heating the molded material causes earlier hardening by driving off any excess water. In addition, heat catalyzes the hydration reaction and greatly increases the rate of curing, reducing the time from 28 days to as low as 2 days at temperatures of about 100"C. Another method of increasing the rate of hardening is by placing the molded material into an autoclave, which subjects the molded article to both elevated temperature and pressure. Autoclaving also results in a final cured material having up to 50% more strength.

c. Preferred Methods of Forming Insulation Barriers.

The structural layer of the laminate insulation barriers of the present invention are preferably formed into a sheet by extruding and/or rolling the hydraulically settable mixture. Laminate insulation barriers are formed by attaching the sheets to conventional insulation materials or highly foamed hydraulically settable or

inorganically filled materials. These will be discussed in turn below.

1. Sheet Forming Methods. A wet sheet molding process can be used to form the hydraulically settable sheets used in the insulation barriers of the invention. The wet sheet molding process is a two step fashioning process in which the hydraulically settable mixture is first molded into a sheet. The sheet may be formed by extruding a hydraulically settable mixture through a die having a width and thickness corresponding to the desired dimensions of the sheet. Alternatively, the sheet may be formed by passing the mixture between a pair of rollers. A combination of these two sheet forming processes is often preferable. A fresh sheet is then molded into the desired shape prior to complete hardening or curing of the sheet.

In more detail, an appropriate hydraulically settable mixture is transported to a sheet forming apparatus comprising an extruder and a set or series of rollers. A currently preferred system includes a mixer and a twin auger extruder, which act in conjunction with reduction rollers. In an alternative embodiment, a sheet may be formed by eliminating the extruder and feeding the mixture directly between the reduction rollers. If an extruder is used to form a sheet, the reduction rollers aid in forming a sheet having a more precise thickness.

The auger extruder can also be replaced by a piston extruder such as a two stage injector or reciprocating screw injector. A piston extruder may be advantageous where greater pressures are required. Nevertheless, due to the highly plastic-like nature of mixtures typically employed in the present invention, it is not generally necessary, or even advantageous _> to exert pressures greater than those achieved using an auger extruder.

Although the preferred width and thickness of the die will depend upon the width and thickness of the particular sheet to be manufactured, the thickness of the extruded sheet will usually be at least twice, and sometime many times, the thickness of the final rolled sheet. The amount of reduction (and, correspondingly, the thickness multiplier) will depend upon the properties of the sheet in question. Because the reduction process helps control fiber orientation, the amount of reduction will often correspond to the degree of desired orientation. In addition, the greater the thickness reduction, the greater the elongation of the sheet. In a typical manufacturing process an extruded sheet with a thickness of about 6 mm may be rolled into a sheet with a thickness between about 0.2 mm and about 0.5 mm.

The amount of pressure that is applied to extrude a hydraulically settable mixture will generally depend on the pressure needed to force the mixture through the die head, as well as the desired rate of extrusion. It should be understood that the rate of extrusion should be controlled in order for the rate of sheet formation to correspond to the speed at which the sheet is subsequently passed through the reduction rollers during the reduction step.

An important factor which determines the optimum speed or rate of extrusion is the final thickness of the sheet. A thicker sheet contains more material and will require a higher rate of extrusion to provide the necessary material. Conversely, a thinner sheet contains less material and will require a lower rate of extrusion in order to provide the necessary material.

The ability of the hydraulically settable mixture to be extruded through the die head, as well as the rate at which it is extruded, is generally a function of the rheology of the mixture, as well as the operating parameters and properties of the machinery. Factors such as the amount of water, organic binder, dispersant, or the

level of initial hydration of the hydraulically settable binder all affect the rheological properties of the mixture. The rate of extrusion may, therefore, be controlled by controlling the mix design and the rate of setting or hardening of the moldable mixture.

Adequate pressure is necessary in order to temporarily increase the workability of the hydraulically settable mixture in the case where the mixture has a deficiency of water and has a degree of particle packing optimization. As the mixture is compressed within the extruder, the compressive forces bring the particles together, thereby reducing the interstitial space between the particles and increasing the apparent amount of water that is available to lubricate the particles. In this way, workability is increased until the mixture has been extruded through the die head, at which point the reduced pressure causes the mixture to exhibit an almost immediate increase in stiffness and green strength.

In light of each of the factors listed above, the amount of pressure which will be applied by the extruder in order to extrude the hydraulically settable mixture will preferably be within the range from between about 50 kPa to about 70 MPa, more preferably within the range from between about 150 kPa to about 30 MPa, and most preferably within the range from between about 350 kPa to about 3.5 MPa.

The extrusion of a hydraulically settable mixture through the die head will orient the individual fibers within the moldable mixture in the lengthwise direction of the extruded sheet. As will be seen hereinbelow, the rolling process will further orient the fibers in the lengthwise or "Y" direction as the sheet is further elongated during the reduction process. In addition, by employing rollers having varying gap distances in the "Z" direction (such as conical rollers) some of the fibers can also be oriented in the "X" direction, i.e., along the width of the sheet. Thus, it is possible to create a sheet

by extrusion, coupled with rolling, which will have bidirectionally oriented fibers.

One of ordinary skill in the art will appreciate that the extrusion step need not formally employ the use of an "extruder" as the term is used in the art. The purpose of the extrusion step is to provide a continuous, well- regulated supply of hydraulically settable material to the rollers. The extrusion step preferably orients the fibers in the direction of the flow of the material. These may be achieved by other mechanisms know to those skilled in the art to effect the "extrusion" or flow of material through an appropriate opening. The force needed to cause a hydraulically settable mixture to flow may, for example, be supplied by gravity. Although the sheets used in making the insulation barriers of the present invention can be directly formed from the extruded sheets, it is preferred to "roll" the extruded sheet by passing the sheet between at least one pair of rollers, the purpose of which is to improve the uniformity and surface quality of the sheet and, in most cases, reduce the thickness of the sheet. In cases where it is desirable to greatly reduce the thickness of the sheet, it may be necessary to reduce the thickness of the sheet in steps, wherein the sheet is passed through several pairs of rollers, each pair having progressively narrower gap distances therebetween.

As the thickness of the sheet is reduced upon passing through a pair of rollers, the sheet will also elongate in the forward moving (or "Y") direction. One consequence of sheet elongation is that the fibers will further be oriented or lined up in the "Y" direction. In this way, the reduction process in combination with the initial extrusion process will create a sheet having substantially unidirectionally oriented fibers in the "Y", or lengthwise, direction.

It is preferable to treat the roller surfaces in order to prevent sticking or adhesion of the sheet to the rollers. One method entails coating the rollers with a nonstick surface such as polished stainless steel, chrome, nickel, or teflon. Another consists of heating the rollers, which causes some of the water within the hydraulically settable mixture to evaporate and to create a steam barrier between the sheet and the rollers. Evaporation of some of the water also reduces the amount of water within the mixture, thereby increasing the green strength of the sheet. The temperature of the rollers, however, must not be so high as to dry or harden the surface of the sheet to the point which would create residual stresses, fractures, flaking, or other deformities or irregularities in the sheet. Accordingly, the rollers are preferably heated to a temperature within a range from about 50°C to about 140°C, more preferably from about 70°C to about 120"C, and most preferably from about 85°C to about 105°C. Generally, the stickiness of the hydraulically settable mixture increases as the amount of water in the mixture is increased. Therefore, the rollers should generally be heated to a higher temperature in cases where the mixture contains more water, which is advantageous because sheets containing a higher water content must generally have more of the water removed in order to obtain adequate green strength.

Because heated rollers can drive off significant amounts of water and improve the form stability, the amount of acceptable sheet thickness reduction will generally decrease in each successive reduction step as the sheet becomes drier. This is because a drier, stiffer sheet can tolerate less shear before flaws are introduced into the structural matrix. Once the sheet has been formed it can then be further used in forming the insulation barriers of the invention.

For example, a portion of the sheet can be fashioned into a desired shape. This is preferably accomplished by pressing the sheet between a male die of a desired shape and a female die having a substantially complementary configuration of the male die shape. Alternative types of dies that can be used include split dies and progressive dies. The articles can also be formed by applying one of many vacuum forming techniques to the sheets.

A dry sheet process can also be used in which the wet sheet as discussed above is subsequently passed over heated drying rollers to form the sheet into a dry paper-like sheet product. In addition, the sheet can optionally be passed between compaction rollers while still in a slightly moistened condition in order to eliminate unwanted voids within the structural matrix, increase the fiber adhesion, reduce porosity, and/or increase surface smoothness. By carefully controlling the water content, it will be possible to ensure that the compaction rollers only compress and increase the density of the sheet without further elongating the sheet.

Substantially dried sheets prepared according to the methods set forth above may be subjected to additional processing steps such as lamination.

2. Laminating Processes. The hydraulically settable sheets formed by the above methods can be used with conventional laminating processes to form laminate insulation barriers. A variety of ⁵ properties can be imparted to a sheet by lamination. For the purposes of this specification and the appended claims, the terms "laminated sheet" or "laminate" (when used as a noun) shall refer to a sheet having at least two layers with at least one of the layers being a hydraulically ° settable material. The terms "laminating material" or

"lamina" shall refer to any constituent layer of the laminated sheet, including both a sheet or other material.

Laminate insulation barriers having any combination of layers are within the scope of this invention to the extent that one layer of the laminate is an insulating material. The laminate can be formed by adding, bonding, or otherwise joining at least two layers together. The thickness of the laminate insulation barrier may vary depending on the nature of the intended purpose of the laminate. ⁰ In the manufacture of a laminate insulation barrier from two or more sheets, at least one of which is a hydraulically settable sheet, various laminating techniques can be used. The sheets can be bonded by many different processes, including wet bond laminating, dry bond ⁵ laminating, thermal bond laminating, and hydraulically settable bond laminating. Useful adhesives include waterborne adhesives (both natural and synthetic) , hot-melt adhesives, and solvent-borne adhesives.

The first basic lamination process is commonly termed 0 a wet bond or a wet laminating process and involves combining two sheets before a solvent which is applied therebetween is removed or is cured. Wet bond laminating of a sheet and another layer involves the use of any liquid adhesive to bond two layers together. After laminating, ⁵ the composite lamination structure passes through a drying system where the water or other solvent is evaporated.

The wet laminating method has traditionally been used to combine one impervious and one porous, or two porous sheets, with an aqueous, solvent, wax, or hot melt adhesive. In wet laminating, the adhesive is applied to the impervious sheet in order to minimize the adhesive usage and combined with the second sheet as soon as possible, followed by drying, cooling, or curing.

Useful natural waterborne adhesives for wet bond lamination include vegetable starch-based adhesives, protein-based adhesives, animal glue, casein, natural rubber latex, hide glues, and silicates. Useful synthetic waterborne adhesives generally include resin emulsions such as stable suspensions of polyvinyl acetate particles in water. Waterborne adhesives are low in odor, taste, color, and toxicity, have a broad range of adhesion, and have excellent aging properties. Useful solvent-borne adhesives include polyurethane adhesives, solvent-borne ethylene- vinyl acetate systems and other rubber resins which are pressure sensitive. If a solvent based adhesive is used, _one of the sheets must be permeable to the solvent so that removal in the drier is not impeded. Thermoplastic polymers are useful hot-melt adhesives that can be applied in a molten state and set to form upon cooling. Hot-melt adhesives generally set quicker than other adhesives. The second basic lamination process is commonly termed a dry bond process which means that the two continuous sheets are combined after a solvent applied therebetween is removed. In dry bond laminating, an adhesive is applied to a substrate, the solvent is removed in a drier and the exposed adhesive is brought into contact with the receptive surface of the secondary sheet in a combining nip.

In contrast to wet bond laminating, most dry bond combining is done at elevated pressures and temperatures. Adhesive coat weights may be very low (0.6 g/m ) to very high (15 g/m or more) . After solvent removal the

viscosities are so high, at least 50 Pa*s, that flow from between the plies is virtually non-existent.

Dry laminating can be contrasted to wet laminating in that the former method is used to combine two impervious sheets. One sheet, preferably the easiest to handle and pass through a drying unit, is coated, the volatiles removed, and then combined with the second sheet in a heated and pressurized nip rolling system.

The third basic lamination process is called a thermal bond process, meaning that two sheets are combined by heat and pressure only. Thermal laminating is more complex than either dry or wet bonding. The high temperatures and pressures normally encountered produce extreme sheet stresses which make outstanding controls mandatory for all variable factors. Small changes in pressure and temperature will affect the bonding of sheets.

Thermal laminating requires a heat activatable element which can serve as the adhesive. This adhesive component may take three forms: (1) a coating preapplied to either or both sheets to be combined; (2) a coating applied in-line which is heat activatable as contrasted to most dry bond adhesives; or (3) a thermoplastic sheet such as an ethylene-vinyl acetate modified low-density polyethylene.

Thermal laminating can be done with the two sheets brought together under pressure at the nip between two rolls, one of which may be heated. Thermal laminating with a single nip between the two rolls will be a slow process with top speed not much above 70 m/min. Making the heated roll very large will increase the top speed in some cases, since this will permit sheet contact (preheat) before the combining nip.

Hydraulically settable bond laminating involves the nature of the hydraulically settable sheets themselves in that the materials thereof are cement-like when in a green or wet state. When green or wet, a hydraulically settable sheet will bond to another hydraulically settable sheet, a

fibrous sheet, or other porous sheet with or without coatings or an adhesive. The bond between the hydraulic¬ ally settable sheet and another layer (or between other layers of the laminate) can range from a slight cling to a bond which exceeds the strength of the hydraulically settable sheet or the material being bonded thereto.

Hydraulically settable sheets can be bonded without the use of adhesives to another layer as long as the hydraulically settable sheet is sufficiently "green" to effectuate an effective bond between the individual laminae. Otherwise, the above discussed laminating methods can be used.

The laminating material that is bonded, adhered, or otherwise joined to the layer of the laminate comprising a sheet may include another sheet, a material which imparts a desired property to the sheet when the two are laminated together, a material which is described below as a coating or an adhesive, or any combination thereof. Examples of materials which enhance the properties of the sheets include organic polymer sheets, metal foil sheets, ionomer sheets, elastomeric sheets, plastic sheets, fibrous sheets or mats, paper sheets, cellophane sheets, nylon sheets, wax sheets, and metallized film sheets.

Conventional laminators can be utilized to combine a sheet with another layer. Laminates can also be created by coextruding two or more sheets or a sheet with another material. Laminate insulation barriers within the scope of the invention can be formed by bonding a sheet and a insulating layer or layers with or without adhesives by the methods discussed above.

D. Specific Insulation Products.

Due to the wide variety of situations where insulation may be desired, the shape, size, thickness, density, texture, content, insulative ability, etc. of the insulation barriers within the purview of the present

invention may vary greatly. For example, hydraulically settable insulation barriers can be used in place of traditional home and building insulation made from, for example, glass wool, polyurethane, or UFFI. Hydraulically settable insulation barriers can also be used to wrap hot water pipes, heating ducts, cooling ducts, refrigeration hoses, or any other conduit which may require an insulative wrapping. Other applications include insulative containers such as coolers, jugs, cups, plates, or cartons. The hydraulically settable insulation materials of the present invention can also be pelletized and used as loose fill insulation. Other uses include various laminate insulation barriers, wallboard, layered and nonlayered insulation blocks placed in attics, walls, floors or anywhere else in a building, foamed insulation injected into spaces such as between two or more walls, and insulating hydraulically settable granules placed between walls or inside spaces.

In a preferred embodiment, the hydraulically settable materials of the present invention are included within laminate insulative sheets or panels. As the hydraulically settable material becomes less dense and more insulative, the strength of the material generally decreases. Depending on the thickness of the desired panel, it often may be possible to simply increase the thickness of the panel in order to increase the gross insulative ability of the panel without reducing the density (and strength) of the panel. In other situations, strength may not be a factor, such as where the insulation material is placed between supporting structures. In that case, the hydraulically settable insulation material can be foamed or doped with lightweight aggregate to increase the insulation ability of the material without regard to the strength characteristics of the material.

In other situations where the insulation panel must be kept sufficiently small, but where both strength and insulation ability are important, it may be necessary to

incorporate within a panel of limited size both properties of high strength and high insulation. In order to manufacture a panel that has sufficient strength and insulation properties it is often desirable to form a laminate, or sandwich structure, which combines two or more sheets together. At least one of the sheets is preferably an ultra lightweight, highly foamed or aerated material having superior insulative qualities. At least one of the other sheets is preferably strong, tough, ductile, and resistant to stress. Often, a thicker, more insulative layer is sandwiched between two thinner sheets of structural material.

Preferred insulative materials include any of the highly foamed, or entrained air containing, hydraulically settable materials described herein. Such hydraulically settable materials may also include any number of lightweight, highly insulative aggregate materials such as perlite, hollow glass spheres, hollow plastic spheres, aerogel, xerogel, sea gel, exfoliated rock, expanded clay, xonotlite, calcined diatomaceous earth, vermiculite, or any other material containing a large amount of entrapped air or space. In addition, in the case where strength is not a factor, lightweight foamed products which do not contain any hydraulic binder can be used, particularly where other means of support or strength are present, such as an attached layer of stronger, more durable hydraulically settable material.

A composite lamination structure suitable for use as a thermal insulation package incorporating in the lamination a hydraulically settable sheet is within the scope of the present invention. The thermal insulation package is made from laminated sheet material which includes an inner layer of hydraulically settable sheet material. An outer layer of aluminum foil and an intermediate layer of fiberglass wetting are also provided in the thermal insulation package. The three layers are

adhesively secured together and the inner surface of the hydraulically settable sheet is coated with a heat- activated adhesive. The sheet material is formed into a tubular section by overlapping opposite edges of the sheet material and heat sealing the edges together. The tubular section thus formed is subsequently cut into tubular sections of smaller length, the bottoms of each of the smaller sections are then heat sealed. The containers thus formed are filled with polystyrene pellets and a hydrate compound is added. The open end of each of the containers is then closed and heat-sealed to form a completed package. The resultant insulation package is fairly inexpensive and capable of being installed in a broad range of structural environments. The actual form, shape, or thickness of the insulation described herein will be determined by the particular need or application in question. The list of different insulation barriers described in this section should be viewed as merely illustrative and not exhaustive. Each of the possibilities cannot be set forth herein although one skilled in the art would be able to alter the shape, thickness, size, or form of the material to conform to a particular need.

III. Examples of the Preferred Embodiments.

To date, numerous tests have been performed comparing the properties of insulation materials of varying composition. Below are specific examples of hydraulically settable compositions which have been created according to the present invention.

Example 1 A plate having good insulation properties was formed from a cementitious mixture containing the following components:

Portland White Cement 2.0 kg

Water 1.004 kg

Perlite 0.702 kg

Tylose ^® 4000 60 g The cement, Tylose ^® , and the perlite were mixed for about 2 minutes; thereafter, the water was added and the mixture was blended for an additional 10 minutes. The resultant cementitious mixture had a water to cement ratio of approximately 0.5. The amount of the cement paste (cement and water) in this cementitious mixture was 79.8% by weight, with perlite comprising 18.6%, and the Tylose ^® being 1.6% by weight of the cementitious mixture.

The resultant cementitious material was extruded and then passed between a pair of rollers to form an insulating plate with a wall thickness of 1/4 inch. The plate had a k-factor of 0.16 W/m*K and a bulk specific gravity of about

1.6 g/cm . In general, the insulation barrier was designed to have a predetermined bulk density by adding porous aggregates such as perlite or calcium silicate micro- spheres. These aggregates have a low specific gravity, and it was believed that they would impart adequate insulative properties to the insulation barriers. However, while these examples demonstrate that it is possible to manufacture a lightweight insulative barrier from cement that was relatively form stable in the green state, they were not as insulative as later compositions in which air entrainment methods were used.

Example 2 A plate having good insulation properties was formed from a cementitious mixture containing the following com¬ ponents:

Portland White Cement 2.0 kg

Water - 1.645 kg Perlite 0.645 kg

Tylose ^® 4000 20 g

Tylose ^® 15002 15 g

Cemfill ^® glass fibers

(4.5 mm; alkali resistant) 370 g

The cementitious mixture was made utilizing the procedures set forth with respect to Example 1, except that the fibers were added after mixing the cement, water, Tylose ^® , and perlite for about 10 minutes. The combined mix was then mixed for an additional 10 minutes. The resultant cementitious mixture had a water to cement ratio of approximately 0.82. The amount of the cement paste (cement and water) in this cementitious mixture was 77.6% by weight, with perlite comprising 13.7%, the Tylose ^® 4000 and 15002 comprising 0.43% and 0.32%, respectively, and the glass fibers being 7.9% by weight of the cementitious mixture.

The resultant cementitious mixture was first extruded and then passed between a pair of heated rollers to form a cementitious sheet. The insulating plate had a higher toughness and fracture energy than the plate of Example 1, and had a k-factor of 0.18 W/m*K.

Example 3 A plate having good insulation properties was formed from a cementitious mixture containing the following com- ponents:

Portland White Cement 4.0 kg

Water 1.179 kg

Sodium silicate icrospheres 1.33 kg Tylose ^® 15002 30 g Cemfill ^® glass fibers

(4.5 mm; alkali resistant) 508 g

The cementitious mixture was made utilizing the procedures set forth with respect to Example 2, except that the microspheres were added in place of the perlite. The resultant cementitious mixture had a water to cement ratio of approximately 0.29, which was dramatically lower than

that of Examples 1 and 2. This demonstrates that depending upon the aggregate system, significantly different water to cement ratios can be designed into the composition. The amount of the cement paste (cement and water) in this 5 cementitious mixture was 73.5% by weight, with the micro- spheres comprising 18.9%, the Tylose ^® comprising 0.43%, and the glass fibers being 7.2% by weight of the cementitious mixture.

The resulting insulation barrier was lighter than ° those in Examples 1 or 2. The cementitious mixture could be readily extruded and passed between a pair or rollers to form the cementitious sheet or plate having a k-factor of 0.16 W/m*K.

While mere early prototypes of the present invention, 5 the insulation barriers prepared according to Examples 1-3 taught that the concepts tested therein were sound. Unfortunately, it was learned that highly adequate in¬ sulative barriers cannot be obtained merely by adding to the cementitious mixture porous aggregates such as those 0 used in Examples 1-3 above. Neither the addition of perlite, nor the calcium silicate microspheres imparted the degree of insulation desired for commercial insulation use. Therefore, other methods of imparting insulation other than by merely adding inorganic materials to the cement matrix ⁵ had to be found.

In the next series of examples, microscopic and discontinuous, nonagglomerated air voids were introduced into the cement matrix, greatly increasing the insulative ability of cementitious insulating barriers. 0

Example 4 A plate having good insulation properties was formed from a cementitious mixture containing the following com¬ ponents: 5

Portland White Cement 2.52 kg

Water 1.975 kg

Vermiculite 1.457 kg

Vinsol resin 2.5 g

⁵ Tylose ^® 4000 25 g

Tylose ^® 15002 75 g

Abaca fiber 159 g

The cementitious mixture was made by prewetting the abaca fiber (which has been pretreated by the manufacturer ° with sodium hydroxide so that greater than 85% of the cel¬ lulose is α-hydroxycellulose) and then adding the excess water and the fibers to the other components except the vermiculite. This mixture was mixed for about 10 minutes, and a further 10 minutes after the vermiculite was added. 5 The resultant cementitious mixture had a water to cement ratio of approximately 0.78. The amount of the cement paste (cement and water) in this cementitious mixture was 72.3% by weight, with the vermiculite comprising 23.4%, the Tylose ^® 4000 and 15002 comprising 0.40% and 1.21%, respec- ⁰ tively, the vinsol resin (an air entraining agent) comprising 0.04%, and the abaca fibers being 2.6% by weight of the cementitious mixture.

The cementitious insulation barrier in this example was molded as above into a rectangular sheet with a wall 5 thickness of about 1/4 inch. The resulting cementitious barrier had a k-factor of 0.16 W/m*K. The surface finish was very smooth, and the barrier had a high toughness and fracture energy.

0 Examples 5-8 A hydraulically settable insulation barrier was formed by passing through a pair of rollers a cementitious mixture containing glass balls (<1 mm) as the aggregate. The components for each example was as follows: 5

Tylose ^® Glass

Example Cement Water FL 15002 Balls

5 4 kg 2.18 kg 200 g 445 g

6 3 kg 1.85 kg 150 g 572 g

7 2 kg 1.57 kg 100 g 857 g

8 1 kg 1.55 kg 100 g 905 g The cementitious mixtures were prepared substantially according to the procedures of Example 4. The resultant cementitious mixture had a water to cement ratios of ap¬ proximately 0.55, 0.62, 0.79, and 1.58, respectively. Even with the high water to cement ratio of Example 8, the cementitious mixture was form stable in the green state and readily moldable. The percentage by weight of the glass balls in each example was 6.5%, 10.3%, 18.9%, and 25.3%, respectively.

These materials were extremely lightweight, having densities in the range from about 0.25 to 0.5. Equally important were the insulative capabilities of a 2.0 mm thick piece of the resultant materials:

Example K-Factor (W/m*IO

5 0.27

6 0.24

7 0.16

8 0.07 It is believed that the insulating abilities of the insulation barriers of Examples 7 and 8 are even greater than indicated. These products were coated with melamine and the solvent in the melamine may have made the effective thickness much less than 2.0 mm. In fact, these products were placed in an oven at 150°C for three hours; there¬ after, they could be removed by hand. This results from the combination of low thermal conductivity and low specific heat of the material. The low specific heat allows the surface of the insulation barrier to quickly radiate energy and become cool, while the low thermal conductivity prevents a replenishing flow of heat from the interior of the insulation barrier to the surface.

Example 9 A relatively high strength cementitious plate was formed for purposes of reinforcing weaker cementitious insulation barriers from a cementitious mixture having the following components:

Portland Cement 2 kg

Water 1 kg

Tylose ^® 4000 60 g

Perlite 0.702 kg The cementitious mixture was formed by mixing the cement, water, and Tylose ^® together in a high speed, high shear mixer for 10 minutes, after which the perlite was mixed in for an additional 5 minutes under low speed mixing conditions. The cementitious mixture was poured into a rectangular mold and made into a plate 1 cm thick. The cured plate had a density of 1.6 g/cm and a k-factor of 0.232 W/m*K. Although this plate showed only a modest degree of insulating ability, it had relatively high strength.

Example 10 A relatively high strength cementitious plate was formed for purposes of reinforcing weaker cementitious insulation barriers from a cementitious mixture having the following components:

Portland Cement 2 kg

Water 1.645 kg

Tylose ^® 4000 20 g

Tylose FL 15002 15 g Perlite 0.645 kg

Glass Fiber 0.508 kg

The cementitious mixture was formed by mixing the cement, water, Tylose ^® , and glass fibers together in a high speed, high shear mixer for 10. minutes, after which the perlite was mixed in for an additional 5 minutes under low speed mixing conditions. The cementitious mixture was

poured into a rectangular mold and made into a plate 1 cm thick. The cured plate had a density of 1.7 g/cm and a k- factor of 0.22 W/m*K. Although this plate showed about the same insulating ability, it had relatively high strength. Because of the inclusion of glass fibers, the insulation barrier of this example had higher fracture energy than the plate of Example 9.

Example 11 A hydraulically settable insulation barrier was formed by sandwiching together a lightweight gel between two cementitious layers. The cementitious layers were formed from a cementitious mixture having the following components: Portland Cement 15 kg

Water 22.5 kg

Tylose ^® FL 15002 0.3 kg

Mearlcrete ^® 0.3 kg

Abaca Fiber 0.25 kg

The components were mixed together in a high speed, high energy mixer for 10 minutes. The Mearlcrete was added to help entrain air within the mixture, while the Tylose ^® helped to stabilize the entrained air. This created a foamed cementitious mixture having lower density than if nonfoamed. The foamed cementitious mixture was made into plates about 1/4 inch thick by pouring the foamed mixture into rectangular molds.

An insulation layer 1 cm thick and consisting of clear aerogel was sandwiched between two of the cementitious sheets formed in this example to form a laminate insulation barrier. The layers were held together by contact cement.

The cementitious sheets had a combined thickness of

0.58 inch. The compressive strength of the laminate was determined to be 0.25 MPa. The flexural strength of the laminate was determined to be 0.8 MPa using a 3-point

bending test on a 10 cm sample. The laminate had a density of 0.32 g/cm ³ and a k-factor of 0.037 w/m*K.

Example 12

A hydraulically settable insulation barrier was formed by sandwiching together a lightweight gel between two cementitious layers. The cementitious layers were formed from a cementitious mixture made by taking 2.5 kg of the foamed cementitious mixture of Example 11 and mixing in 1 kg of hollow glass spheres having a maximum diameter of 200 microns under low speed mixing conditions. The resulting cementitious mixture was made into plates having a thickness of about 1/4 inch pouring the mixture into rectangular molds. An insulation layer 1 cm thick and consisting of aerogel doped with carbon (graphite) to increase the insulative ability was sandwiched between two of the cementitious sheets formed in this example to form a laminate insulation barrier. The layers were held together by contact cement.

The combined thickness of the cementitious layers was 0.67 inch. The resulting laminate had a density of 0.304 g/cm and a k-factor of 0.036 W/m*K.

Example 13

Hydraulically settable sheets were made substantially according to Example 11, except that only 0.125 kg of abaca fiber was used in this example. An insulation layer consisting of sea gel 0.7 inch thick was sandwiched between two of the cementitious sheets to form a laminate insulation barrier. The cumulative thickness of the cementitious sheets was 0.56 inch. The laminate had a density of 0.213 g/cm and a k-factor of 0.051 W/m*K.

Example 14 A laminate insulation barrier was formed using the cementitious plates formed in Example 12 and an insulation layer consisting of sea gel. The different layers were glued together using contact cement. The insulation layer had a thickness of 0.7 inch, while the cementitious sheets had a cumulative thickness of 0.67. The laminate had a density of 0.187 g/cm and a k-factor of 0.048 W/m*K.

Example 15

A laminate insulation barrier was formed substantially according to Example 14, except that the cementitious plates within the laminate had a cumulative thickness of 0.59 inch instead of 0.67 inch as in Example 14. Conse¬ quently, because the sea gel made up a larger percentage of the overall mass of the laminate in Example 15 compared to the laminate in Example, the former had a lower density and higher insulating ability than the latter.

The compressive strength of the laminate was determined to be 0.06 MPa. The flexural strength of the laminate was determined to be 0.78 MPa using a 3-point bending test on a 10 cm sample. The laminate had a density of 0.165 g/cm and a k-factor of 0.042 W/m*K.

Example 16

An insulating barrier was formed by molding the foamed cementitious mixture of Example 14 in a rectangular mold. The thickness of insulating barrier was l.l inch, the density was 0.282 g/cm and the k-factor was 0.068 W/m*K.

Example 17

A noncementitious mixture was made from a mixture which contained the following components:

Water 1.65 kg Tylose ^® FL 15002 0.2 kg

Abaca Fiber 0.1 kg

Hollow Glass Spheres (< 200 microns) 0.905 kg The water, Tylose ^® , and abaca fiber were mixed together in a high speed mixer for 5 minutes, after which the hollow glass spheres were added and mixed for an additional 5 minutes under low speed conditions. The mixture was poured into a rectangular mold and formed into a plate 0.985 inch thick. The density was only 0.154 g/cm and the k-factor was 0.045 W/m*K. The plate formed in this example had relatively low strength characteristics but was extremely lightweight due to the lack of cement. This material would be suitable as the more insulating layer attached to one or more cementitious sheets using adhesion means known to those skilled in the art.

Example 18

A foamed cementitious mixture was obtained by combining 2 kg of the cementitious mixture obtained in Example 13 with 1 kg of hollow glass spheres (< 200 microns) . This foamed cementitious mixture containing glass spheres was made into a plate 1.075 inch thick using a rectangular mold. The resulting cementitious plate had a density of 0.228 g/cm and a k-factor of 0.065 W/m*K.

Example 19 The cementitious mixture obtained in Example 11 was made into a plate 0.935 inch thick using a rectangular mold. The cementitious plate had a density of 0.418 g/cm and a k-factor of 0.119 W/m*K.

Example 20

A cementitious mixture was made which he the following components:

Portland Cement 15 kg

Water 15 kg

Tylose ^® FL 15002 0.3 kg

Surfactant (A0728) 0.3 kg

Abaca Fiber 0.25 kg

The components were mixed together using a high energy, high shear mixer for 10 minutes. The surfactant was an amine oxide sold by Exxon as A0728 ^® . Carbon dioxide was incorporated into the cementitious mixture by placing C0 ₂ gas over the surface of the mixture as it was being mixed. Thereafter, 2 kg of this resulting mixture was mixed together with 1 kg of hollow glass spheres (< 200 microns) using a low speed mixer. The addition of C0 ₂ was found to increase the foam stability of the mixture, thereby maintaining smaller, more uniformly distributed voids throughout the mixture.

The foamed cementitious mixture with glass spheres was formed into an insulation barrier 0.965 inch thick using a rectangular mold. The density of the barrier was 0.428 g/cm and the k-factor was 0.089 W/m*K.

Example 21 A cementitious mixture was made which had the following components:

Portland Cement 15 kg

Water 22.5 kg

Tylose ^® FL 15002 0.3 kg

Surfactant (A0728) 0.3 kg Abaca Fiber 0.25 kg

The components were mixed together according to the procedure of Example 20. Thereafter, 2.9 kg of this resulting mixture was mixed together with l kg of hollow glass spheres (< 200 microns) using a low speed mixer. The addition of C0 ₂ was found to increase the foam stability of the mixture, thereby maintaining smaller, more uniformly distributed voids throughout the mixture.

The foamed cementitious mixture with glass spheres was formed into an insulation barrier 1.04 inch thick using a rectangular mold. The density of the barrier was 0.4 g/cm ³ and the k-factor was 0.110 W/m*K.

Example 22 A hydraulically settable insulation barrier was formed by molding in a rectangular mold a cementitious mixture which had the following components:

Portland Cement 15 kg

Water 22.5 kg

Tylose ^® FL 15002 0.3 kg

Surfactant (A0728) 0.3 kg

Abaca Fiber 0.125 kg

The components were mixed together according to the procedure of Example 20. The resulting foamed cementitious mixture was immediately molded into an insulation barrier which had a thickness of 0.993 inch, a density of 0.396 g/cm ³ and a k-factor of 0.110 W/m*K. The addition of C0 ₂ was found to increase the foam stability of the mixture, thereby maintaining smaller, more uniformly distributed voids throughout the mixture.

Examples 23-25 The cementitious mixture of Example 21 was formed into insulation barriers having the following characteristics:

Density K-Factor Example (g/cm ) (W/m»K)

23 0.338 0.089 24 0.304 0.071

25 0.303 0.065

The variation in the densities and k-factors can be accounted for by the ability of the cementitious mixture to have greatly varying amounts of entrained air. This could be due to variations in the mixing time or the speed with which the mixtures were mixed.

Tests showed that the insulation barrier made in

Example 25 had excellent strength characteristics, with a compressive strength of 1.2 MPa and a flexural strength of 1.7 MPa.

Example 26 A hydraulically settable insulation barrier was formed from a cementitious mixture having the following components:

Portland Cement 0.5 kg

Water 1.65 kg

Tylose ^® 4000 0.05 kg

Tylose ^® FL 15002 0.05 kg

Glass Fiber 0.15 kg

Hollow Glass Spheres 1.0 kg

The components (except for the hollow glass spheres) were mixed together in a high speed, high shear mixer for about 10 minutes, after which the hollow glass spheres were added and the mixture mixed at low speed for an additional 5 minutes. The resulting mixture was poured into a rectan- gular mold to form an insulation barrier which was 1.03 iinncchh tthhiicckk,, 1had a density of 0.137 g/cm , and a k-factor of 0.040 W/m*K.

Example 27

A laminate insulation barrier was formed by sandwiching a ultra lightweight, highly insulating gel material between a pair of cementitious sheets formed from a cementitious mixture having the following components: Portland cement 10 kg

Water 1.8 kg

Glass Fiber 0.35 kg

Superplasticizer (WRDA 19) 0.4 kg

The components were mixed together using a high speed, high shear mixer for about 6 minutes. Thereafter the cementitious mixture was poured into a mold to form cementitious sheets. The mixture was also alternatively be passed through a pair of rollers to form a flat sheet. The molded sheets were found to -have a high compressive strength, namely 150 MPa, making the plate highly ductile and impact resistant.

Aerogel doped with carbon (graphite) , which had a thickness of 0.394 inch, was sandwiched between two of the cementitious sheets formed above, the sheets having thick¬ nesses of 0.125 inch and 0.123 inch, respectively. The insulation barrier had a total thickness of 0.642 inch, a density of 1.263 g/cm and a k-factor of 0.021 W/m*K.

Example 28 A laminate insulation barrier was formed by sandwiching a ultra lightweight, highly insulating gel material between a pair of cementitious sheets formed from a cementitious mixture having the following components: Portland cement 0.5 kg

Water 1.65 kg Tylose ^® 4000 0.05 kg

Tylose ^® FL 15002 0.05 kg

Glass Fiber 0.15 kg

Hollow Glass Spheres 1.0 kg

The components (except the hollow glass spheres) were mixed together using a high speed, high shear mixer for about 10 minutes, after which the hollow glass spheres were added and the mixture mixed at low speed for an additional 5 minutes. Thereafter the cementitious mixture was formed into ultra thin sheets by passing the mixture through a pair of rollers.

Aerogel doped with carbon (graphite) , which had a thickness of 0.433 inch, was sandwiched between two of the cementitious sheets formed above, the sheets having thick¬ nesses of 0.075 inch and 0.08 inch, respectively. The insulation barrier had a total thickness of 0.588 inch, a density of 0.208 g/cm and a k-factor of 0.021 W/m*K. Although the insulation barrier of Example 28 had similar insulation characteristics compared to the barrier of Exam¬ ple 27, the latter was much stronger due to the inclusion of thicker cementitious sheets for structural support.

While the following examples are hypothetical in nature, they are based upon similar mix designs which have either been made, or which were calculated and extrapolated from actual mixes. However, these examples are presented this way in order to more specifically teach those skilled in the art the compositions and methods of the present invention.

Examples 29-32 The cementitious mixtures of these examples are identical to those of Examples 5-8, except that varying amounts of abaca fiber is added.

Corresponding Amount of

Example Example Abaca fiber

29 5 149 g

30 6 152 g

31 7 180 g

32 8 181 g

The resultant percentage by weight of the abaca fiber in these examples is 2.1%, 2.7%, 3.8%, and 4.8, respectively. These cementitious materials are as insulative as those of Examples 5-8, but they are much tougher and have a higher fracture energy. Hence, the use of these abaca fiber, as well as other types of fiber, is particularly desirable in situations where such characteristics are desirable.

Examples 33-35

Rectangular plates composed of cementitious mixtures of these examples are prepared according to the procedures of, and using the components of, Example 5 (i.e., 4 kg of portland white cement is used) with the exceptions that aluminum powder (<100 mesh) and NaOH were added to the cementitious mixtures in the following amounts and the resultant molded plates are heated to about 80°C for 30-60 minutes:

Example Aluminum NaOH

33 4 g 21.9 g

34 6 g 34.7 g

35 8 g 34.7 g The NaOH is added to the cementitious mixture to activate the aluminum by establishing a pH in the preferable range of about 13.1-13.8. The result is that the porosity of the cementitious mixture is increased, the bulk density is decreased, and the insulation capability is increased.

It is important to note that shrinkage cracks have not been observed in experiments which have been conducted under conditions which are not dissimilar to those delineated in Examples 33-35, even though the cementitious mixtures are heated and much of the water is driven off rapidly.

Examples 36-38 Rectangular plates composed of cementitious mixtures of these examples are prepared according to the procedures of, and using the components of. Example 6 (i.e. , 3 kg of portland white cement is used) with the exceptions that aluminum powder (<100 mesh) and NaOH is added to the cementitious mixtures in the following amounts: Example Aluminum NaOH

36 3 g 18.6 g

37 4.5 g 29.5 g

38 6 g 29.5 g

The NaOH is added to the cementitious mixture to activate the aluminum by establishing a pH in the preferable range of about 13.1-13.8. The resultant molded plates are heated to about 80°C for 30-60 minutes. The result is that the porosity of the cementitious mixture is increased, the bulk density' is decreased, and the insulation capability is increased. The plates of Examples

36-38 are lighter and slightly more insulative than those of Examples 33-35.

Examples 39-41

Rectangular plates composed of cementitious mixtures of these examples are prepared according to the procedures of, and using the components of. Example 7 (i.e., 2 kg of portland white cement is used) with the exceptions that aluminum powder (<100 mesh) and NaOH are added to the cementitious mixtures in the following amounts.

Example Aluminum NaOH

39 2 g 15.8 g

40 3 g 25.0 g

41 4 g 25.0 g The NaOH is added to the cementitious mixture to activate the aluminum by establishing a pH in the preferable range of about 13.1-13.8. The resultant molded plates are heated to about 80°C for 30-60 minutes. The result is that the porosity of the cementitious mixture is increased, the bulk density is decreased, and the insulation capability is increased.

The plates of Examples 39-41 are much lighter and have a much greater insulating capability than the plates of Examples 33-38. Nevertheless, the strength of these plates is less that those with a greater concentration of hydraulic cement.

Examples 42-44 Rectangular plates composed of cementitious mixtures of these examples are prepared according to the procedures of, and using the components of, Example 8 (i.e., 1 kg of portland white cement is used) with the exceptions that aluminum powder (<100 mesh) and NaOH are added to the cementitious mixtures in the following amounts:

Example Aluminum NaOH

42 1 g 15.8 g

43 1.5 g 25.1 g

44 2 g 25.1 g The NaOH is added to the cementitious mixture to activate the aluminum by establishing a pH in the preferable range of about 13.1-13.8. The resultant molded plates are heated to about 80°C for 30-60 minutes. The result is that the porosity of the cementitious mixture is increased, the bulk density is decreased, and the insulation capability is increased.

The plates of Examples 42-44 are even lighter and have even greater insulating capability than the plates of Ex¬ amples 39-41. Again, the less amount of hydraulic cement results in a slightly weaker product.

Examples 45-47

Cementitious plates are formed by passing through a pair of rollers, cementitious mixtures containing the com¬ ponents for each example as follows:

Example Aluminum NaOH

45 10.0 g 22.3 g

46 15.0 g 22.3 g

47 22.5 g 22.3 g In each of these examples, there is 4 kg of portland white cement, 1.4 kg of water, and 40 g of Tylose ^® 15002. The cementitious mixtures are prepared substantially according to the procedures of Example 1, with the exception that no aggregates are added. The resultant cementitious mixtures have a water to cement ratios of approximately 0.35. These materials are extremely light¬ weight and are very insulative because of the amount of air incorporated into the mixtures.

Examples 48-50

Cementitious plates are formed by passing through a pair of rollers, cementitious mixtures containing the com¬ ponents for each example as follows:

Example Aluminum NaOH Abaca Fibers

48 10.0 g 22.3 g 60 g

49 15.0 g 22.3 g 60 g

50 22.5 g 22.3 g 60 g In each of these examples, there is 4 kg of portland white cement, 1.4 kg of water, and 40 g of Tylose ^® 15002. The cementitious mixtures are prepared substantially according to the procedures of Example 1, with the exception that fibers rather than perlite aggregates are added. Like the cementitious mixtures of Examples 45-47, these materials are extremely lightweight and are very insulative because of the amount of air incorporated into the mixtures. However, the cementitious mixtures of these examples have increased toughness and fracture energy because of the addition of the fibers.

Example 51 Any of the hydraulically settable materials described in any of the previous examples are broken up into fragments. Such fragments can be used as loose fill insulation. In addition, they can be reincorporated into other hydraulically settable mixtures and molded or formed into new hydraulically settable insulation barriers.

Example 52 Any of the hydraulically settable mixtures used in any previous example is formed into the shape of pellets. Such hydraulically settable pellets can be used as loose fill insulation. In addition, they can be reincorporated into other hydraulically settable mixtures and molded or formed into new insulation barriers.

Example 53 Any of the hydraulically settable mixtures used in any previous example is formed into the shape of an insulative liner. This liner is generally the shape of a container into which it can be placed to make the container more insulative, such as an ice cooler, refrigerator, partition, jug, pitcher, cup, plate, encasement, pipe, duct, or compartment.

Example 54

Any of the hydraulically settable mixtures used in any previous example is formed into the shape of an insulative container. The container might be in the shape of an ice cooler, refrigerator, partition, jug, pitcher, cup, plate, encasement, pipe, duct, or compartment.

Example 55 A highly insulating laminate insulation barrier is formed by first placing hollow glass spheres within a mold. The diameters of the glass spheres are chosen to optimize the packing ability of the spheres within the mold so that the glass spheres occupy 70% of the volume within the mold. A highly thixotropic cementitious mixture containing cement, water, fibers, a superplasticizer water reducing additive (WRDA 19) , and a rheology modifying agent (Tylose ^® ) is placed into the mold through an opening in the top, the mold and the contents therein are subjected to strong, vibration and/or pressure. The vibration and/or pressure causes the thixotropic cementitious mixture to temporarily become less viscous, increasing the ability of the mixture to flow into the spaces between the individual aggregate particles.

When the material within the mold has reached suffi¬ cient form stability, it is removed from the mold, after which one or more sides of the molded material is laminated

with a relatively thin layer of the cementitious material described in Example 11.

The molded layer containing the hollow glass spheres provides the bulk of the insulation ability of the laminate, while the layer of stronger cementitious material containing abaca fibers provides structural support. The result is a highly insulative laminate with a k-factor of at least 0.06 W/m*K.

Where the average diameter of the individual glass spheres is relatively high, the final product can be made stronger by adding a fine aggregate material to the cemen¬ titious mixture, such as fine sand, quartz, or silica.

Example 56 A laminate insulation barrier is manufactured substan¬ tially according to method set forth in Example 55, except that the diameters of the hollow glass spheres are optimized so that the spheres occupy 80% of the volume within the mold. The result is a highly insulative laminate with a k-factor of at least 0.05 W/m*K.

Example 57 A laminate insulation barrier is manufactured substan¬ tially according to method set forth in Example 55, except that the diameters of the hollow glass spheres are optimized so that the spheres occupy 90% of the volume within the mold. The result is a highly insulative laminate with a k-factor of at least 0.04 W/m*K.

Example 58

A laminate insulation barrier is manufactured substan¬ tially according to method set forth in Example 55, except that the diameters of the hollow glass spheres are optimized so that the spheres occupy 95% of the volume within the mold. The result is a highly insulative laminate with a k-factor of at least 0.035 W/m*K.

Example 59

A laminate insulation barrier is manufactured substan¬ tially according to method set forth in Example 55, except that perlite particles having varying diameters are sub¬ stituted for the hollow glass spheres. The result is a highly insulative laminate with a k-factor of at least 0.06 W/m*K.

Where the average diameter of the individual perlite particles is relatively high, the final product can be made stronger by adding a fine aggregate material to the cemen¬ titious mixture, such as fine sand, quartz, or silica.

Example 60 A laminate insulation barrier is manufactured substan¬ tially according to method set forth in Example 55, except that the diameters of the perlite particles are optimized so that they occupy 80% of the volume within the mold. The result is a highly insulative laminate with a k-factor of at least 0.05 W/m*K.

Example 61 A laminate insulation barrier is manufactured substan¬ tially according to method set forth in Example 55, except that the diameters of the perlite particles are optimized so that they occupy 90% of the volume within the mold. The result is a highly insulative laminate with a k-factor of at least 0.04 w/m*K.

Example 62 A laminate insulation barrier is manufactured substan¬ tially according to method set forth in Example 55, except that the diameters of the perlite particles are optimized so that they occupy 95% of the volume within the mold. The result is a highly insulative laminate with a k-factor of at least 0.035 W/m*K.

Example 63 A laminate insulation barrier is manufactured substan¬ tially according to method set forth in Example 55, except that a mixture of hollow glass spheres and perlite particles having varying diameters are substituted for the hollow glass spheres. The result is a highly insulative laminate with a k-factor of at least 0.06 W/m*K.

Example 64 A laminate insulation barrier is manufactured substan¬ tially according to method set forth in Example 55, except that vermiculite particles having varying diameters are sub¬ stituted for the hollow glass spheres. The result is a highly insulative laminate with a k-factor of at least 0.06 W/m*K.

Example 65 A laminate insulation barrier is manufactured substan¬ tially according to method set forth in Example 55, except that diatomaceous earth particles having varying diameters are substituted for the hollow glass spheres. The result is a highly insulative laminate with a k-factor of at least 0.06 W/m*K.

Example 66

A laminate insulation barrier is manufactured substan¬ tially according to method set forth in Example 55, except that fibers are placed in the dry mold together with the hollow glass spheres. The result is a highly insulative laminate with a k-factor of at least 0.06 W/m*K.

IV. Summary.

From the foregoing, it will be appreciated that the present invention provides novel compositions and processes used in making hydraulically settable insulation barriers which are useful in any application where high insulation

at low cost is desired, particularly in the construction industry, or in the manufacture of appliances.

The present invention also provides novel compositions and processes used in making hydraulically settable insulation barriers which have insulating and other properties comparable to that of polystyrene foam or other organic insulation materials, but which are more environmentally neutral. Specifically, the present invention does not require the use of, or emit, chemicals which have been implicated as causing depletion of the ozone layer, nor does it create unsightly garbage which does not degrade, or which only very slowly degrades over time in landfills.

In addition, the present invention also provides novel compositions and processes used in making hydraulically settable insulation barriers which can be produced at costs that are comparable or lower than those of conventional insulation materials.

Further, the present invention provides novel compositions and processes used in making hydraulically settable insulation barriers which are much more environmentally sound if ever disposed of than other insulation materials, such as asbestos, UFFI, or styrofoam. The present invention provides novel compositions and processes for hydraulically settable insulation barriers which are essentially comprised of the same compounds as the earth, and are similar to dirt and rock, and therefore pose little or no risk to the environment if discarded into landfills. The present invention further provides novel compositions and processes for which the raw materials may be obtained from the earth, eliminating the need to further deplete the already dwindling petroleum reserves in order to obtain the parent materials as is required for the manufacture of many insulation products, particularly blown organic foams like polystyrene or UFFI.

The present invention further provides novel compositions and processes for improving the safety of insulation barriers within buildings, in that the hydraulically settable insulation barriers do not release harmful chemicals like formaldehyde into the building in which the insulation was placed.

The present invention further provides novel compositions and processes for improving the recyclability of insulation materials, particularly since the hydraulically settable materials can be reintroduced into new hydraulic paste as an aggregate, or be incorporated as a suitable aggregate in many other hydraulic cement applications.

The present invention further provides novel compositions and processes for manufacturing lightweight and insulative wallboard which still has sufficient structural, flexural, and tensile strength like gypsum board.

The present invention further provides novel hydraulically settable insulation barriers which will maintain their shape without external support during the green state and rapidly achieve sufficient strength so that the molded barriers can be handled using ordinary methods.

The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects as illustrative only and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.