CONSTRUCTIVE ARRANGEMENT APPLIED TO A MODULAR STRUCTURAL PANEL AND METHOD OF PREPARING THE SAME

FIELD OF THE INVENTION The present invention refers to a constructive arrangement comprising a sandwich-structured assembly, in wherein its components are joined by means of a specific adhesive material. More specifically, said constructive arrangement is applied to a modular structural panel intended for use in the furniture industry, as well in civil construction.

RELATED ART

Alternatives to building constructions using conventional materials, such as wood and concrete, have been researched in order to optimize the building work. Additionally, as a consequence of optimization, there has been an effort to reduce construction time and costs, as well as to overcome other disadvantageous aspects arising from the period during which construction takes place.

Modular structural panels for construction of walls, partitions, finishing in general, and also used in the manufacture of furnitures are usually described by the literature.

However, the vast majority of panels used are composed of low-quality materials, compromising the mechanical strength thereof, thus are not suitable to undergo effects caused by natural factors of the environment which they are applied to.

The choice of the type of material to be used during construction is one of the most important steps in the design, since an inappropriate choice may result in waste of material during the construction work, thereby increasing the cost thereof.

The use of materials, such as concrete and masonries, for example, in the construction of base structures, as well as in the construction of sealing walls, creates a need for additional use of ceramic bricks with grout and cement mortar. Further, finishing up with a mass formed by clay and cement, as well as the eventual use of stirrups and hoops is also necessary.

In certain building projects, the use of these materials is very costly due to the need of skilled labor. Working with these types of materials leads to a high physical strain on workers, which is often the main factor contributing to changes in the project schedule so that the construction completion deadline is delayed.

Nowadays, an alternative to the use of concrete and the use of masonry consists in the use of particleboard-based structural panels. However, the application of these types of materials is highly restricted, since they can not be used in the external area of the building, as they are not resistant to the action of rain water and moisture.

A myriad of other materials for the production of modular panels are disclosed in the art, such as panels prepared

with asbestos cement, whose use is disadvantageous due to the fact that they have a high cost, in addition to making the environment much hotter.

In its turn, gypsum panels give rise to structural problems in the building, in addition to not being resistant to moisture, having a high cost, and being subjected to the physical effects caused by bad weather conditions.

Also described in the literature are panels in which the coating is made of fiber materials, particularly mineral fibers. In these cases, the main limitation to the use of said panels is due to their high thermal conductivity. Heat and moisture are easily conduced to the internal environment when using this kind of panel.

Structural panels prepared with steel plates are difficult to handle and restricted in use due to their susceptibility to corrosion as a result of being exposed to climate changes; thus, are difficult to obtain as they require the use of additional equipments for assembly, which raises the costs of the work. In addition, they also expose workers to serious risks due to its cutting capability.

The major drawback of all these materials usually described in the art is that fact that they are extremely susceptible to climate changes, resulting in losses and inconveniences to users. Effects caused in panels due to climate changes cause said panels to bend with ease.

Other disadvantageous technical characteristics of the panels described in the art are extremely relevant to show existing drawbacks, which are now pointed out herein.

- difficult panel assembly; - difficult panel installation;

- sensitivity to finishing;

- reduced mechanical strength;

- reduced weatherproofmg;

- requires the use of heavier plates to improve strength;

- low fire resistance;

- reduced durability;

- increased job cost; and

- requires the use of additional equipments to join its components.

Furthermore, for said panels usually made of masonry, plywood, gypsum, metal material, or even reinforced concrete structures, the installation of beams and columns for supporting the structure is required. Accordingly, there is a need for making cuts into already assembled walls in order to insert the respective components. Nevertheless, this represents a long time spent in preparing the panels.

Specifically, with respect to sandwich- structured structural panels, which aim at a higher efficiency as to

its thermal-acoustic insulation, among other advantages, the same did not achieve a good market acceptance at first, since they have low resistance to fire, compromised durability, and a high cost.

One of the most commonly used materials as a filler for said panels is glass wool due to its ability to withstand temperature changes. However, the art shows some drawbacks regarding the use of glass wool to that purpose, since glass wool particles in suspension when in closed environments are very detrimental to health. An alternative to the use of glass wool to that purpose is the use of expanded polystyrene plates - EPS. However, at moment, panels disclosed in the art provided with EPS plates as a filler for sandwich panels are extremely disadvantageous due to the complexity of production which requires a higher assembling time, the use of additional materials to give strength to the same, restrictions on use and coatings, structural fragility when it becomes necessary to subject the panel to an additional procedure for installation of electro-hydraulic services. The handling and transportation of panels made of reinforced mortar and EPS, for example, must be supervised and performed carefully. Due to the heavy weight of panels, transportation is made with the use of crane trucks.

It is possible to find in the literature an infinity of documents discussing about this subject. Document

WO 2006/070280 discloses a structural panel formed by multiple layers as a sandwich, comprising an inner layer of polyurethane or polyisocyanurate. Such substances used in the inner layer are heat-sensitive thus represent a fire hazard; its burning results in the emission of poison gasses, such as hydrocyanic gas, due to the presence of isocyanates in the composition of polyurethanes.

The construction of panels having thermal- acoustic insulation characteristics for use as walls, ceilings or floor, consisting of a plurality of relatively solid elements having low thermal conductivity and resistant to water and fire is disclosed in US Patent 4,167,598. However, the drawback concerning the obtainment and handling thereof makes the use of said panels disadvantageous.

US Patent 2006/0080923 discloses the production of a concrete panel provided with insulating sheets, which aims to minimize the labor during construction.

Brazilian Patent PI0206004-3 discloses a panel provided with specific characteristics which allow it to be used specifically in the construction of buildings intended for habitation.

Brazilian Patent PI0402199-1 discloses a constructive system formed by an expanded polystyrene core; however, its side surfaces are formed by metal meshes welded and covered with mortar. In the art, the best properties were achieved by

using EPS plates as a filler for sandwich panels. EPS is a proven insulating material, widely used in most developed countries in the construction field aiming at energy saving.

Its lightness, strength, workability, and reduced cost made of it an ideal product. It is a plastic material in the form of foam having closed microcells made up essentially of 2% polystyrene and 98% air, being produced in 2 versions: flame retardant and non-flame retardant. EPS is neither inflammable nor self-extinguishing, since it has in its composition a combustion inhibitor. When in contact with a flame, non-inflammable EPS shrinks itself, making ignition harder to occur.

Although the art is replete with documents discussing sandwich modular panels applied to the furniture industry and civil construction, it can be clearly seen that the drawbacks shown herein are disclosed therewith.

And, in view of the numerous drawbacks related to modular panels existing in the art, the present invention was developed to provide a modular panel technique which is able to overcome said drawbacks shown herein. SUMMARY OF THE INVENTION

The present invention refers to a constructive arrangement applied to a modular structural panel, which is used in situations wherein a higher resistance to impacts and action of water is desired. More specifically, said panels are preferably intended for use in the furniture industry, as well in civil

construction. The constructive arrangement of the present invention comprises a sandwich-structured assembly formed by joining two sheets of a suitable building material. Suitably arranged between said sheets is a plate composed of a material having low density, vibration-resistance, insulation, and thermal- acoustic characteristics. The structured assembly of the present embodiment keeps itself joined by means of a specific adhesive material, which is able to give to said assembly essential and unique characteristics for its intended applications DETAILED DESCRIPTION OF THE

INVENTION

The present invention refers to a constructive arrangement applied to a modular structural panel, which is used in situations where a higher resistance to impact and action of water is desired, such as that required for facades, in addition to providing the structural panel with a fire-retardant property.

More specifically, said panels are preferably intended for use in the furniture industry, as well as in civil construction, used, for example, in the construction of rooms, sealing of internal and external areas, bathroom modules, bedrooms, mezzanine floors, etc., and also in the manufacturing of shelfs, assembly of cabinets, various pieces of furniture (tables, benches, bookstands, etc.), room dividers, sealing partition walls, ceilings, elevated floors, decorative panels, temporary fencing, shed assembly, job sites, used in cold storages, coverings, saunas,

among other internal and/or external environments of a building.

The diversity of use of the structured assembly of the present embodiment is due to the intrinsic characteristics of said assembly, among which one could point out specifically the thermal-acoustic property; the fact that it does not propagate fire; accepts any kind of finishing such as painting, ceramic fixing, stones, melamine laminates, metals, glasses, wallpaper, wood, etc.; withstands bad weather, such as heat and cold; is resistant to moisture, structural vibrations, earthquakes; said assemblies being preferred to the manufacturing of room expansion kits and can also being as cooling containers.

The constructive arrangement of the present invention comprises a sandwich-structured assembly formed by joining two sheets of a suitable building material. More particularly for the present embodiment, plates of cementitious material were employed, which are preferably chosen from SFRC (Synthetic Fiber Reinforced Concrete). According to the intended application of said plate, it can be used with various mold shapes, such as rectangular, square-shaped, circular, oval-shaped, etc. However, the present invention is not limited to the use of sheets of cementitious material, and can also be applied to sheets of building materials selected from concrete, wood (plywood and/or particle board), glazed tile, ceramic, bricks, gypsum, stone, metal, dry-wall, among others. Suitably arranged between said sheets of

cementitious material is a plate composed of a material having low density, vibration-resistance, insulation, and thermal-acoustic characteristics, which can be selected from glass wool, expanded polystyrene, cork, polyurethane foams, etc. However, specifically for the present embodiment, an insulating plate of an expanded polystyrene material -EPS (Styrofoam) was chosen.

The constructive solution predetermined for EPS determines its eventual contribution to the risk in case of fire; further, in the case of the structured assembly of the present embodiment EPS is coated with cementitious plates, which are composed of an incombustible and fire-resistant material.

The composition of the structured assembly developed herein comprising a EPS plate as a filler does not represent any supplementary fire hazard to a building or furniture, thanks to the low density of EPS; in addition EPS is non- inflammable, fire-retardant, does not release residues or toxic effluents nor produce chlorofluorocarbon (CFC), which is currently a substance of high concern due to global warming, and, above all, is a 100% recyclable material. The structured assembly formed by the cementitious plates of the present embodiment is ideal for the assembly of Styrofoam prototypes into metals or walls for thermal and acoustic insulation.

One of the essential characteristics of the invention described herein lies in the fact that its constructive

form combines in a single element the whole structural function required during a construction, shows mechanical strength both when required in the horizontal direction and in the vertical direction, is safe, durable, resistant to impacts, rodents and insects, is not liable to decomposition, rotting or even deterioration, provides comfort to users and is not harmful to health, since it is resistant to fungi, molds, and parasites.

Said structured assembly keeps itself joined by means of a specific adhesive material, which is able to give it essential and unique characteristics for its intended applications.

More specifically, the adhesive material consists of a polymer formulated in a single component, provided with a high thermal stability and having better physical and mechanical properties. Additionally, said material is of easy application, which results in a lower assembly cost and a finished product obtained with increased competitiveness in the market.

Still referring to the adhesive material, it is water-based; has a low water content; and is based on a vinyl elastomer having high flexibility and resistance to shear, impacts, and thermal variation. It is an environmentally friendly material, since it is free of volatile, inflammable and harmful to health (toxic) organic materials, and is used as a replacement material for adhesives which use organic substances, since the adhesive material developed and used herein is also free of catalysts, commonly amines or isocyanates present in bicomponent glues.

Such characteristics make the handling of the adhesive more safe to operator.

Other chemical products with adhesive properties may also be used in the present embodiment in order to join the structured assembly. Nevertheless, certain essential characteristics which ensure the efficiency of the structured assembly may be compromised by the use of another type of adhesive material.

Particularly the adhesive material, in addition to being provided with specific properties which give it a strong adhesion, also has waterproofing properties and fills in gaps in the structures.

Said adhesive material is resistant to temperatures lower than O ⁰ C. Its resistance is preserved in a temperature range which varies from about 0 to -30 ⁰ C, and it also shows resistance to high temperatures, which may range from about 150-200 ⁰ C.

A temperature change within established limits does not compromise the efficiency of the adhesive material. Within these temperature ranges, the adhesive material does not show any loss of performance nor of its original elasticity, which allows for compensations in the presence of dilatations from different materials, which are adhered by said adhesive.

The inherent characteristics of said adhesive material enable it to be of easy application, free of organic

substances, such as solvents, allow a easy removal, that is, a simple cleaning in case of a excess application of the adhesive material, which is easily accomplished by means of cloths and wet tissue. Said adhesive material allows its application to be clear, without emanating strong smells which are irritative to the smell of the operator or persons that may be close to the application site.

After the application of said adhesive material to the object of interest, and after its full drying, said object can be subjected directly to extreme moisture conditions, since the adhesive material is highly resistant.

Once the adhesive material is dried, it provides a high strength to the object, since said adhesive material has a high average shear strength of about 70 Kgf/cm after complete cure. Additionally, said adhesive adheres immediately to the material to be applied, without flowing out along the same.

The adhesive material used in the present embodiment enables various kinds of materials to be strongly joined with Styrofoam, or even pieces of Styrofoam to be joined with each other, without the need of using additional equipments, such as hydraulic presses, in order to ensure the efficiency of this joint between elements making up the structured assembly. Using this specific adhesive material provides a combination of high adhesion force and flexibility, which are necessary in order to

avoid detachments and cracks of the cementitious plates, and allows the panels to be subsequently cut.

The process of building the structured assembly formed by cementitious plates, object of the present invention, is fast thanks to the efficiency of the adhesive material employed.

According to the adhesive material used in the present embodiment, the drying time of the glue used as an adhesive depends upon the amount of glue applied on the material to be glued, wherein said amount is dependant on the weight or stress which the material to be glued must withstand.

The handling time of the adhesive material after application on the material to be glued is of approximately 15 minutes. The full cure of the adhesive material occurs about 1 to 3 weeks after its application. During this curing period, all tensile stress is applied on the adhesive material due to the accommodation of the glued filler and the cementitious plate, both of which are flexible materials having a large difference in their coefficient of thermal expansion. However, the curing period varies according to the surface of the material.

The best efficiency results of the adhesive material used in the present embodiment are achieved when at least one of the surfaces of the material to be glued is provided with porosity. The structured assembly of the present

embodiment can be used in the internal and external environment of the building. Said assembly is stiff, fire-retardant, weatherproof (including heat and cold), moisture-resistant, ideal for the manufacturing of room expansion kits and can also be used as cooling containers.

The structured assembly may be provided with various thicknesses, depending upon its intended application. The thickness of said assembly is adjusted according to the thickness of the filler. The structured assembly of the present embodiment is a product provided with low thermal conductivity, lightweight, reduced water absorption, high impact absorption capacity, and good mechanical and compressive strength.

A further advantage of the structured assembly proposed herein lies in that it is an environmentally friendly product, provided with characteristics which are necessary for green buildings, which have been developed by companies as a model of excellence in sustainability for buildings, since developer and construction companies are increasingly concerned with this new concept.

Improvements on quality, cost reduction, and increased return on investments, as well as an appreciation of the company brand, since its image is directly associated with environmental awareness, are just an example of advantages provided by the present invention.

As a result of being composed of CFS, adhesive material, and EPS, that is, all components and materials being sustainable, the structured assembly reveals itself as a new material falling under sustainability standards. For a preferred embodiment of the present invention, acoustic insulation was ensured by selecting an EPS specially prepared for that effect. Such selected EPS was preferably EPS T for absorption of step noises - in a thickness of 20 to 30 mm. However, in case that only thermal insulation properties are desired, the choice of EPS used should be preferably for EPS 60, or having a specification higher than 60, provided with a minimum thickness of 30 mm.

In a laboratory test, the structured assembly proposed herein was subjected to various conditions in order to evaluate its characteristics. With respect to acoustic insulation and efficacy for impact noises, said test showed a 32dB gain measured in laboratory in the reduction of the transmission of step noises. Comparatively to the temperature resistance, said assembly exhibits better results when subjected to work conditions in which temperature varies from about -4O ⁰ C to 9O ⁰ C. Compressive strength was measured according to NBR 8082, compressive strength at 10% strain, wherein a result superior to lOOKPa was obtained. During compression the structured assembly behaviors elastically until strain reachs about 2% of the

thickness of the panel. However, upon ceasing application of force to cause straining of the panel, the structured assembly proposed herein recovers its shape and takes its original thickness.

One of the major characteristics of the present invention relates to the fact that the structured assembly is used in a plurality of applications, which can range from residential and industrial projects, commercial, hospital and school areas, being adaptable to any kind of finishing available on the market, as well as to the use in furniture manufacturing, such as tables, chairs, laboratory benchs, cabinets, etc.

The structured assembly meets the needs of construction workers, such as easy adjustment and assembly of structural elements, easy handling and transportation, not requiring installation of internal structural elements to reinforce the load supporting fixing structure, and also easy accomplishment of services for preparing tubing installations and wirings internal to panels without structural compromise.

The process of construction of said structured assembly is described in more details in the following: Low-thickness and flexible cementitious plates, with shapes and thickness previously selected according to the kind of application, must be dry-cleaned, by means of simple and usual apparatuses, such as a bristle broom, such that any unbound and undesirable particles which could impair the efficiency of the adhesive material are removed from the surface of the sheet.

Cementitious plates used in the present embodiment have as basic materials in its composition, cement and lightweight mineral aggregates (perlite, cellulose fibers, etc), and may further contain additives. Next, a first cementitious plate must be suitably positioned in a flat location, such that its finished surface forms the first surface of the external side, remaining in direct contact with the surface of said flat location used for positioning said plate. After positioning the cementitious plate, a glue for adhesive material specific to this kind of bonding is applied on the top surface of the cementitious plate, preferably with the aid of a spatula.

However, as described above, the present invention is not limited to the use of this adhesive material glue and other substances having these characteristics can also be applied in order to provide the plates developed herein with the sealing characteristic.

Subsequently to application of said glue, a Styrofoam sheet having the same size and shape as the cementitious plate and a thickness previously selected according to the application intended for the panel presently manufactured must be positioned on the cementitious plate in a parallel manner, thereby promoting the immediate gluing of the cementitious plate to the Styrofoam sheet.

Thereupon, glue is applied again on the top surface of the Styrofoam sheet, such that immediately after the second cementitious plate is applied in order to promote its adhesion to the Styrofoam sheet and thus obtain, as a final product, the structured assembly object of the present invention.

The second cementitious plate must have dimensions and shapes identical to those of the first sheet used and must be positioned in a parallel manner on the Styrofoam plate, such that its finished surface forms the second surface of the external side of the cementitious plate.

About 20 minutes after the start of the process for manufacturing the structured assembly, the product object of the present invention is obtained, that is, a sandwich-structured assembly formed by joining two cementitious plates and a Styrofoam sheet.

A further embodiment of the present invention relates to the optimization of the process for obtaining the sandwich-structured assembly. Said process consists in passing the Styrofoam sheet on a gluing machine, which contains the specific adhesive material.

With the use of the gluing machine both faces of the Styrofoam sheet will be simultaneously provided with glue.

Accordingly, on one face of the Styrofoam sheet a first cementitious plate which has been cleaned and has the same size as the Styrofoam sheet is placed and then, on the other face, a

second cementitious plate having a size similar to the first one is placed. Thus, the sandwich is obtained and, hence, the structured assembly object of the present invention.

Once the structured assembly is obtained, weights are placed directly upon the top surface of the glued assembly. Still alternatively, in the case of the optimized process, the force applied on the assembly for full pressing is promoted by the weight itself of remaining modules of the structured assembly formed herein, which are being stacked on each other after being obtained.

The full cure of the structured assembly in order to allow additional procedures to be carried out therewith, such as cuts on the assembly and hole-making, is obtained after about 3 days of gluing. The structured assembly obtained in the present embodiment provides tensile strength and very low elongation, due to its dilatation and deformation capabilities. It can also be coated, in a totally secure manner, with ceramic, natural stones, mortar, etc. Thanks to the inherent characteristics of the structured assembly provided by the adhesive material, modular panels obtained herein may be used as a basis for virtually any type of coating in non-structural internal and/or external closures and sealings. More specifically, said structured assembly was developed to be used as modular panels for application in wet

and/or hot environments, which may or may not be exposed to bad weather.

The structured assembly obtained is incombustible, and can be used as an element in the field of furnitures, decoration, or civil construction in the building of stairwells, stair pressurization ducts and escape routes, or even as fire walls and/or fire barriers; is inert to the action of water, thus being applicable to eaves, facades, bathrooms, kitchens, as well as other areas subjected to the action of water; saunas, basement false walls, marquees, porticos, etc; is used as a basis for vertical and horizontal coatings, can be painted, coated with mortar, stones, ceramics, laminates in general, glasses, mosaics, wood floors, cabinets, wood benches, etc, and also allow thermal- acoustic insulation. Advantages provided by the structured assembly developed by the present invention lies in a higher execution speed of furnitures or walls in external and internal closures, which has as a consequence an increase on productivity; the assembly is lightweight and easy to handle; debris production is reduced during construction; electrical installations, and the like, are executed in the interior of walls and before sealing thereof, thus making these works easier and faster, as well as avoiding material loss; high resistance to impacts and moisture action; and reduction of structural loads and foundations. In a preferred embodiment of the present

invention, the structured assembly is used to form walls or partitions. In this embodiment, the use of metal structures is also necessary.

The most commonly-used structures are those U-shaped, rigid U-shaped, and H-shaped. Said structures make up guides, which are horizontal pieces fixed to the ground and ceiling, as well as uprights, which consist of vertical pieces having suitable spacings installed in the interior of guides.

A guide is fixed to the ground in such a way to serve as a basis, by means of removable fasteners, such as special- purpose screws. Joints are treated with proper strips and masses, in order to promote sealing and ensure wall watertightness, as well as a smooth and uniform surface, to which the final finishing may be directly applied. The structured assembly is coupled to the guide basis such as to form a stable and safe frame, wherein the structured assembly is fixed to the guides by means of an adhesive material, such as Pesilox®, which is a highly-resistant glue able to withstand ultraviolet radiation and water. After 2 hours of application, Pesilox® has a shear strength of about 4Kg/cm of application. After full cure, Pesilox® exhibits a resistance of about 18 Kg/cm . Once the metal structure is lifted, if necessary, the eventual installation of electric, hydraulic, and other components should be made, which will make up the metal structure of the building project. After installing these additional components, the sealing of the wall and treatment of joints is

carried out.

The invention described herein is not limited to this embodiment and it will be apparent to those skilled in the art that any specific characteristic introduced therein should be construed merely as something that was described in order to provide a better understanding and may not be earned out without departing from the inventive concept described. The limiting characteristics of the object of the present invention are related to claims which are part of this specification.