AND INSTALLING SAME

TECHNICAL FI D

This invention relates to insulation material and methods of preparing and installing same.

In particular, but not exclusively this invention relates to thermal and/or acoustic insulation for use in housing and buildings.

BACKGROUND ART

There are various types of thermal insulation available including for instance, fibreglass batting, polyester batts, polystyrene blocks, gypsum compositions, reflective foil, cellulose fibre and macerated paper (sometimes sold under the trade mark INSULFLUFF™).

Unfortunately all of the above products have problems associated with them. Fibreglass which is the insulation material most commonly used is heavy for its volume and difficult to handle on account of the fibreglass fibres irritating human skin. INSULFLUFF™ insulation material tends to blow around and can also be difficult to handle. Also, none of the aforementioned materials breathes, absorbs and releases moisture to any significant extent, which is an important property to have when it is considered that insulation is expected to last the life of the building in which it is installed. Further, some of the above insulation materials are suspected to be carcinogenic.

There is an optimal relationship between density and thickness to ensure maximum thermal resistance. This relationship needs to be maintained

over the installed life of the product. One of the problems is devising a material that will not compact over time. Another problem is to ensure that the product has fire retardent properties and does not produce large smoke volumes under conditions of pyrolysis.

It is an object of the present invention to address the above problems, or at least to provide the public with a useful choice.

Further objects and advantages of the present invention will become apparent from the following description which is given by way of example only.

DISCLOSURE OF INVENTION

According to one aspect of the present invention there is provided an insulation material (containing natural wool) which has been subjected to a particular process intended to maintain a thickness over a period of time. This process ensures the maintenance of the thickness over a longer period than would be achieved by other forms of processing, or no processing at all-

Including natural wool in thermal insulation materials overcomes a number of problems associated with the prior art. Wool is lightweight, non-carcinogenic, easy to handle and very importantly can breath, absorb and release moisture.

In some embodiments of the present invention, the insulation material includes an additional component which gives structure to the wool. This component may be any material that provides the property of providing a structure to the wool without adversely affecting the other properties desired in an insulation material to a significant extent. For instance, the

structural component may be a material (such as a silica bonding mix or a polymeric material) with a melting point sufficiently low to melt when the insulation material (such as a silica bonding material) or a polymeric material with a melting point sufficiently low to melt when the insulation material is heated in an oven. Upon returning to room temperature, the structural component may harden forming a semi-rigid structure holding the wool. For ease of reference, the structural component shall be referred to as polymer throughout this specification although it should be appreciated other structural components may be used.

Sometimes more than one type of polymer may be used. For instance there may be included polymer of two different deniers, densities, molecular construction and chemical compositions and hence different melting points. The high-melt polymer may act to provide structural characteristics to the wool and to enable its mass to retain its open structure. The low-melt polymer melts in the cooking process and bonds both the wool and the high-melt polymer fibres.

The denier of the polymer can vary. As an example, the high melt polymer can have a denier in the order of 3 to 40 D. The denier of the low melt polymer can be as low as 3 D.

Likewise, the ratio of wool to polymer can vary greatly depending on the situation for which it is desired to use the insulation material. A typical mix for the present invention could have 50-65% wool, 20-30% low melt polymer and 10-20% high melt polymer.

In preferred embodiments of the present invention, the insulation material includes wool, a structural fibre, a bonding agent and a packing fibre having a denier or diameter that is less than the denier or diameter

of the structural fibre.

The structural fibre may form a network having interstices into which the wool and the packing fibre lies. As the packing fibre has a lower denier/diameter than the structural fibre it can fit readily into the interstices provided by the network of structural fibres.

Further, wool and the packing material reduce the circulation of air and create a barrier by reducing the size and increasing the number of interstices left by the network of structural fibres. Heat can be transferred by insulation and radiation which are not desirable properties of an insulation material.

In preferred embodiments, the bonding agent is used to bond the structural fibre together into the network. The bonding agent may also bond the wool and packing fibre as well as the structural fibre. The bonding action of the bonding agent is enhanced if it has a similar chemical composition to the structural fibre. The term 'similar chemical composition' shall means compositions which are in the same general family and have an affinity for bonding with each other. For example, the structural fibre and the bonding agent may both be polyesters, although they may have different deniers, chain lengths and melting points from each other.

In preferred embodiments, the bonding agent has a similar chemical composition to the packing fibres. Wool is a difficult fibre to bond or entangle together. The incorporation of a fine packing fibre into the insulation material provides many points of contact with the wool and the structural fibre. If the packing fibre has a similar chemical composition to the bonding agent, then these points of contact are bonding points or

entangling points as well with the bonding agent joining together the packing fibre plus joining or entangling the wool with the packing fibre.

BEST MODES FOR CARRYING OUT THE INVENTION

In preferred embodiments of the present invention the structural fibre, packing fibre and bonding agents are all polyester, although it should be appreciated that other materials may be used. In one embodiment, the structural fibre may be high melt polyester having a denier of between 18 and 60 D. A preferred denier is 25 D. The packing fibre may also be high melt polyester and have a denier of between 3 and 10 D. A preferred denier for the packing fibre is 6 D. The bonding agent may be low melt polyester having a low denier in the order of 3 to 10 D.

If the bonding agent has a lower melting point than the wool, structural fibre and packing fibre, then it can be mixed in with these fibres in ^' a dry form. The insulation material can then be heated to a temperature below the melting point of the wool, structural fibre and packing fibre, but above the melting point of the bonding agent. This heat can cause the bonding agent to melt thereby fusing or entangling with the wool, packing fibre and structural fibre. When the insulation material is brought back to room temperature, the bonding agent solidifies thus forming the desired structure.

An example of the proportions of the fibres to each other in insulation material is given below.

Any fibres used may well be already fire-retarded in their original manufacture or part process thereof thus making that part of the product fire-retarded without further treatment.

Sometimes it will be necessary to increase the fire retardant properties of the insulation material. The applicant has found that spraying with certain compounds prior to cooking can provide the desired effect. In particular spraying with phosphoric acid with a concentration in the order of 8% by weight works well. Phosphoric acid has been found to be a fire retardant which binds to the wool fibre and absorbs water from the atmosphere. While phosphoric acid is the most promising at this stage other substances may be used such as sodium borate other boron and phosphorous and nitrogen containing compounds.

In addition to, or perhaps separate from the application of acid, sodium silicate may be used to coat the wool fibres to provide a further fire retardant effect. Sodium silicate neutralises the acidity of the phosphoric acid. A concentration of sodium silicate in the order of 400g/m of material (20mm thick, 100mm wide) has been found to work well.

Good quality wool however is expensive as its processing costs to allow it to be used commercially are expensive.

In one embodiment of the present invention, low grade wool is used in the insulation material. Low grade wool and in particular oddment wool is inexpensive as its processing costs to allow it to be used commercially are expensive. One of the reasons for this is that the wool is often combined with animal excrement which along with the associated odour is difficult to remove.

To overcome the above problem, in one method the applicant treats the wool using acid in the last bath of the scouring process to disintegrate the residual carbonaceous matter and destroy the odour-forming compounds. The choice of acid can vary as can the concentration. It has been found however that in one embodiment a concentration in the order of 2% of sulphuric or phosphoric acid is quite effective.

In contrast to the traditional treatment of wool prepared for insulation processes, in preferred embodiments the wool is not descaled. The applicant has found that because of the inclusion of a network provided by the structural fibre, and the product is not dry-cleaned, slept on, or handled excessively over its life-span it has not been necessary to descale. The fibres are held apart by the structure and not crushed together. Further, by not descaling, an expensive step in the traditional treatment of wool for the insulation process is avoided.

Expensive wool types have the natural resilience which is given by the helical nature of the wool fibres. Low grade wool however has substantially straight wool fibres and therefore less natural resilience.

In one embodiment of the present invention, resilience is added to the insulation material by having the packing fibre configured to have a greater resilience than straight packing fibre. For example, the packing fibre could be crimped which is a configuration that low denier high melt polyester can come in.

In one embodiment of the present invention the insulation material may be prepared by the following method.

a) Low grade or oddment wool is scoured with 2% phosphoric acid used in the last bath to decarbonise the wool.

b) The scoured wool is mixed with low melt and high melt polymer as previously described.

c) The wool mix is blended or pre-carded with standard machinery such as a dolfer.

d) The blended wool mix is carded into layers approximately 20mm thick and placed onto a conveyor.

e) The layers may be sprayed with a combination of high concentration phosphoric acid and sodium silicate to provide fire retardant properties.

f) The insulation material formed from five layers and conveyed into an oven to be cooked at a temperature in the order of 80 - 160°. Fans may be used to blast hot air through the material. The formed blanket may be sprayed with phosphoric acid or other fire-retardant chemicals.

g) The cooked material is then conveyed to further ovens to remove moisture.

h) The insulation material in its final state is cut to length and placed in rolls.

It should be appreciated that methods other than that described above may be used.

Traditional insulation normally comes in the form of self-supporting batting which are fitted between studs and nogs and must retain their installed position to retain the insulating effect over their lifetime. The traditional batt however frequently collapses under its own weight and because it is not secured to the framing its insulation properties are markedly reduced. By having a layered blanket the present invention can be permanently affixed to the framing and provide a stable insulation barrier for the life of the building. The fixing is simply achieved by peeling back the outer layer at the edges only and fixing this to the wooden framing and nogs. By having a layered blanket, the present invention can be readily attached to walls, ceilings and so forth without a significant loss of insulation.

According to an alternative aspect of the present invention, there is provided a method of installing insulation in a building characterised by the step of positioning a blanket of insulating material over the thermal bridges in the building.

In a building, the wooden framing provides thermal bridges. That is, the thermal resistance of the framing is lower than the other building materials and thereby creates a thermal bridge through which the heat

flows. The applicants have recognised that by covering existing rafters by an insulation blanket the thermal bridges are minimised. When, for constructional reasons the blanket must be placed between the rafters the insulation can be precut to appropriate widths and fitted as almost continuous strip. Thus reducing possible thermal bridging by eliminating joins normally found in conventional insulating batting or plastic blocks systems. This method also reduces installation labour costs by up to 60%.

It should be appreciated that the present invention has uses outside of that of just supplying insulation for buildings. For instance, the present invention can be used as a natural substitute for foams and plastics. The invention can be used as padding, in furniture and as an insulator for other situations, for instance in dog kennels.

It should be appreciated that aspects of the present invention have been described by way of example and that modifications or additions may be made thereto without departing from the scope of the appended claims.