WO1995006679A1

WO1995006679A1 - Fibre reinforced plastic compound material and articles made therefrom

Info

Publication number: WO1995006679A1
Application number: PCT/AU1994/000518
Authority: WO
Inventors: Norman Maurice O'brien
Original assignee: Seacrest Building Pty. Ltd.
Priority date: 1993-09-01
Filing date: 1994-09-01
Publication date: 1995-03-09
Also published as: JPH09504312A

Abstract

A fibre bundle (10) having an outer enhancer coating (11) adapted to enhance encapsulation of the fibre by settable plastics resin material (12). The fibres can be a synthetic fibre where the outer enhancer coating has been applied to the fibre or alternatively the fibre can be a naturally occurring oiled fibre such as sheepswool where the outer coating is lanolin. Lanolin can also be recovered from wool processing water and used to coat other fibres so that the same encapsulation effect occurs upon blending with the settable plastics material, the use of this oil layer enhances intimate coating of the fibres when blended with the settable plastic and by selecting the appropriate coating for the particular plastic, an improved result in distribution of the plastic through a finished article is obtained provided, of course, that proper quantities are used.

Description

"FIBRE REINFORCED PLASTIC COMPOUND MATERIAL AND ARTICLES MADE THEREFROM"

TECHNICAL FIELD OF THE INVENTION THIS INVENTION relates to a fibre reinforced plastic compound material and in particular but not limited to fibre reinforced plastic articles having a relatively lightweight interior and a relatively dense, durable external surface coating.

BACKGROUND ART

Many forms of composite material are known where a settable synthetic resin is reinforced with a fibrous reinforcing material. For example, reinforced resin such as fibreglass, fibre reinforced plaster, adobe and such like may be used where the tensile strength of the fibres strengthen the resin once it has set.

However, complete encapsulation of fibres by the resin is not assured and therefore bonding between the fibres and the resin is not uniform through the final product creating a less than optimum finish.

OUTLINE OF THE INVENTION It is an object of the present invention to alleviate, at least to some degree, the aforementioned problems associated with the prior art.

The applicant has examined the application of coatings on reinforcing fibres to enhance intimate and preferential contact and encapsulation of fibres when forming fibre reinforced plastic articles. The use of coated fibres, according to the applicant's investigations, promotes a chemical or chemical and physical reaction where a settable plastics tends to "track" the fibres so that in the case of a lightweight article, the use of a selected coating can result in all fibres being coated preferentially by the tracking action and leaving voids within the article, the size and distribution of the voids depends upon the amount of plastic material employed, but nevertheless, the fibres are encapsulated resulting in a stronger article. The applicant has found that, in the case of natural animal fibres having a natural oil coating, this "tracking effect" occurs even if some of the natural coating is removed.

In one aspect therefore, the invention resides in an article forming process forming a fibre reinforced plastic article from naturally coated fibres or uncoated fibres using the chemical properties of those coated and/or uncoated fibres.

In a further aspect, the present invention resides in a process for forming material and/or a plastic material utilising the chemical properties of animal and/or other naturally grown or produced fibres. In another form of the present invention, there is provided a process for forming a material utilising the chemical properties of a wool fibre and/or its natural lanolin or other coating properties.

In another aspect, the present invention resides in a process for forming a material utilising the chemical process created by the use of a synthetic and/or a natural fibre artificially or otherwise coated with lanolin and/or natural or synthetic fire retardant coating.

In still another form, the present invention resides in a process for forming a material utilising the chemical properties of lanolin additive or ingredient to promote additional fire resistant qualities to a material or a product. In still another form, the present invention resides in a process for forming a material utilising the chemical properties of lanolin coatings applied to a natural and/or artificial or other fibres to enhance the fire retardant qualities of a material or a product.

In a still further aspect, the present invention resides in an article forming process for forming a fibre reinforced plastic article from a blend of fibres and a settable plastic material, the article being formed while the blend is in a fluid or semi-fluid state and subsequently allowed to cure, the process comprising the steps of:-

(a) providing coated fibres where a major portion of the fibres are coated with an enhancer for promoting coating of the fibres with the settable plastic;

(b) subsequently forming a blend of the coated fibres with the settable plastic material;

(c) subsequently or simultaneously forming the article; and (d) allowing the article to cure..

The fibres can be a naturally coated fibre, for example, sheepswool or the fibres can be artificially coated. The preferred coating is typically lanolin which is preferred in the case of an isocyanate based settable plastic, but other combinations having mutual affinity and attraction for the purpose of enhancing coating of fibres with the plastic can be employed.

Preferably, the coated fibres are pre-treated before the blending step. The pre-treatment can include treatments selected from the following:-

(i) blending the coated fibres with auxiliary fibres or filler material, the auxiliary fibres and filler material also preferably being coated with the enhancer; (ii) the addition of water to the fibres preferably as a spray mist or steam;

(iii) preheating the fibres to a predetermined temperature desirable for article forming; (iv) addition of a fire retardant;

(v) pre-treating fibres by applying a finely dispersed or gaseous phase of the enhancer to coat the fibres with the enhancer.

After blending, the blend or the article can be treated according to one of the following steps:-

(vi) forming the article according to a moulding or extrusion process; or (vii) applying a coating being preferably a fibre reinforced coating to the article or an assembly of the articles before or after curing. Where fibres and- fillers are not pre-coated with the enhancer, it is preferable in step (a) to blend the fibres and fillers together in a raw state and apply the enhancer, either in the abovementioned step (v) or by passing the fibres through a bath containing the enhancer to coat the fibres and fillers at the same time to thereby provide the coated fibres. Where a bath or other suitable means are employed to apply the enhancer to the fibres and/or filler blend, it is preferable to also add other desirable additives at this stage. For example, a fire retardant in the form of alumina trihydrate can be employed with the enhancer to simultaneously coat the fibres and provide fire retardant qualities to the final article. Other examples include borax as a fire retardant, additives having other properties can be added, lanoline, ceramic, cementitious material and so forth. The coating of the finished article is preferably applied as a surface membrane prepared according to steps (a) and (b) above, where the fibre is a chopped fibre with fibres having a length ranging from 1 mm to 10mm. In a preferred form, the surface membrane is made up of about 1 5% by volume plastic, 1 5% by volume water and about 70% by volume of fibre at preparation. The surface membrane typically can be from .5mm to 5mm thick. The coating preferably includes a refractive selected from the following:- (i) clay and/or; (ii) cementitious material. In another aspect, there is provided apparatus for producing fibre reinforced articles according to the above process from the enhancer coated fibres, the apparatus comprising:-

(a) a coated fibre storage and delivery means;

(b) a settable plastics material storage and delivery means; and (c) a blending and/or article forming means for receiving the coated fibres and simultaneously blending the fibres with the settable plastics material just prior to or during formation of the article. The apparatus further typically employs heating means for raising the temperature of the coated fibres to a temperature desirable for the blending and article forming stage. Typically, steam heating means is employed to apply steam to the fibres. The blending and/or article forming means is typically either a mould or an extruder.

One typical article is a prefabricated article of an assembly made up of a plurality of said articles, the surface coating being applied to the assembly so that at least two of the articles share a common coat. The assembly typically comprises a plurality of interlocking building panels.

In one preferred embodiment, the article is formed in a mould and the blending step takes place in the mould utilising the forming process within the mould. The fibres can be natural animal, vegetable or mineral fibres selected from the following:- (i) Sheepswool or natural equivalent; (ii) Cotton; (ϋ) Jute; (iii) Flax; (iv) Coconut; or (v) Other natural, organic or mineral fibres and including mixtures of same. Alternatively, artificial fibres can be employed, typical examples being the following:- (i) Glass fibres; (ii) Metal fibres; or (iii) Other artificial fibres including mixtures of same.

The fire retardant can be any suitable fire retardant. Alternatively, and/or in combination ultraviolet resistant additive including kaolin and/or alumina trihydrate or functional equivalent can be employed.

Additionally, a filler such as polystyrene bead scoria, glass spheres or other type spheres and/or other filler material may be added, and the settable plastic may be a foam including cementitious or other material and/or have a foaming agent added.

Additionally, reinforcing material such as steel or wool rod and/or other material may be used with the settable plastic to meet design requirements, preferably attached to outer membranes in strategic places and/or other places required by engineering design.

The settable plastic typically is selected from known settable plastics such as poiyurethane, polyester, epoxy, melamine formaldehyde and/or phenolic resins, acrylics, acrylonitrile butastyrene, polyamides, noryl, other polymers and such like. Additionally, an elastomer such as latex rubber or such like may be employed. In a preferred embodiment, the fibrous reinforcing material is sheepswool and the settable liquid is poiyurethane.

For example, the composite may range from the softest and most flexible foam and/or flexidurable wire and/or other coatings to the hardest structural and/or load bearing material. Almost any combination of strength durability softness or hardness may be engineered into the product according to the desired requirements of end use. Moreover, a composite material may be produced with unusual rheological properties such as displacement under constant load but resilience under shock load or such like.

Suitably, the method may also include the preparation of the fibrous material such as by separation, cleaning or other conditioning of the fibre, teasing of the fibre or such like and/or producing wool or other entwinements for heavier reinforcements may be formed in composite by inclusion in the mould and/or by first manufacturing in the extruding moulding process.

Formation of the composite material is preferably achieved by introducing the fibre to the settable plastic by passing the fibre through a venturi tube and/or other method of placement and impacting the fibre reinforcing material cast from the venturi tube with the settable plastic.

Formation of a creep resistant material is preferably achieved via a matrix of overlaying, overlapping and/or crossing of fibres in any and all directions bound and set in the material to provide a herringbone type reinforced effect throughout the product in all directions from any given point. For example, the fibres can be layed at plus or minus 45°.

Additionally, the settable plastic and the fibre may be provided with an electrostatic charge of opposite sign whereby the materials are attracted to one another in forming the composite material. It will be appreciated that the settable liquid may be introduced in two or more parts as required such as in an isocyanate part and a polyol part for the formation of a poiyurethane resin.

Preferably, other structural aggregate material, either coated with enhancer or not, may be added such as void forming material scoria, recycled garbage, recycled paper, binding agents, coalescing agents, foaming agents or such like. Suitably, the reinforced material is carried through the venturi by a carrying medium such as compressed air or the like.

Alternatively, the material may be introduced into a mould having an electrostatic charge of opposite sign to the remainder of the material.

Additionally, the settable plastic may be adapted to react with and/or form a chemical bond or the like to the fibre, such as a reaction between the isocyanate of a poiyurethane resin with a natural oil such as lanoline in sheepswool.

Additionally, a mass of fibre may be coated so as to form globules in a honeycomb effect in the composite material or can also be aerated to form such honeycomb effect or provide air spaces or gaseous spaces wherein the settable plastic coats only the outside surface of the mass of fibre and/or air or gaseous space. The settable liquid may be adapted so that its surface coalesces to form a skin or membrane on the body of the composite material when formed and set. A reinforced membrane of high density may preferably be laid up to all surfaces of a mould which may be filled with the reinforced material of this invention to form a sandwich panel with a high density strong durable surface and a low density reinforced or other core. The mould may be a hinged mould which is sealed to enclose an article to be manufactured prior to or after the introduction of the settable liquid. Alternatively, a mould may be filled with a reinforcing fibre and loosely divided or finely divided or gaseous medium be passed therethrough to react with the coated fibre and encapsulate the fibre for use as a low density core to a structural building or automotive component or such like. The surfaces of the mould may have prior coating of a finish coat and/or a reinforced or other membrane applied before any core material is inserted.

Accordingly, the stress points of a structural element may be manufactured with additional strength by adding additional and/or stronger fibres and/or heavier density polymer material. The mould may be filled non-homogeneously with reinforcing and void forming material as required.

In another embodiment, a reinforced membrane material may be formed by combining fibres and/or other non-homogeneous materials with a hard or durable and/or flexidurable resin and/or other material to provide the required characteristics for a product in use. Alternatively, a mould may have the required amount of settable and/or other slow reacting or forming material placed in the bottom of the mould, the mould then filled or part thereof with an interlocked coated fibre and/or other loosely assembled coated fibre blanket such as wool insulation material or vice versa. The lid tightly sealed in time for the foaming and encapsulation of the coated reinforcing fibre materials. Alternatively, the mould may be closed and the core material inserted via a venturi tube to form a panel and/or a sandwich panel. Using the same or similar or other methods of manufacture combined with variations in the engineering properties or structure of the polymer material or materials the following products may be provided by way of non-limiting example: high fibre rated material; high fire resistance coatings; fire resistant clothing; reinforced membrane car bodies; artificial timber; structural building panels; roofing and wall cladding and other products for buildings or other uses; mechanised replacement of the fibre glass industry; moulded furniture and white goods; reinforced cable insulation; or may other product types in the market place. The surface coating and/or panel membrane may be formed from a higher and/or high density material preferably sprayable composite material. Such surface coating/membrane will preferably included chopped fibres, UV resistant material, fire resistant material and/or other suitable material bound by a suitable material such as phenolic or polyester and/or other suitable material, to provide a strong, durable and resilient product surface.

Such product surface may be used in the formation of car bodies and/or other membrane type products, composite products, composite sandwich and/or other building panels, composite building and/or other structures and other uses obvious to the trained professional. BRIEF DESCRIPTION OF THE DRAWINGS

In order that the invention can be more readily understood and be put into practical effect, reference will now be made to the following drawings and examples and wherein:-

Figures l a and 1 b are schematic diagrams illustrating the effect of the present invention upon a bundle of fibres;

Figure 2 is a flow diagram showing a general process according to the present invention and in block form apparatus used;

Figure 3 is a section through a typical article, in this case, the article is a lightweight building panel made using the process of Figure 2 using sheepswool as the coated fibres;

Figure 4 is a close up view of a structural panel embodying the teachings of the present invention; Figure 5 is a further example of a process according to the invention employing a moulding step;

Figure 6 is a section through part of an assembly, in this case, a building employing building panels of the type illustrated in Figure 3; and Figure 7 is a detailed view illustrating application of the present invention to a coated article.

METHOD OF PERFORMANCE

Referring to the Figures and initially to Figures 1 a and 1 b, there is illustrated a fibre bundle 10 with one fibre shown enlarged and schematically illustrating a fibre having an outer enhancer coating 1 1 adapted to enhance encapsulation of the fibre by settable plastics resin material 12. The fibres can be a synthetic fibre where the outer enhancer coating has been applied to the fibre or alternatively the fibre can be a naturally occurring oiled fibre such as sheepswool where the outer coating is lanolin. Lanolin can also be recovered from wool processing water and used to coat other fibres so that the same encapsulation effect occurs upon blending with the settable plastics material.

The applicant has found that the use of this oil layer enhances intimate coating of the fibres when blended with the settable plastic and by selecting the appropriate coating for the particular plastic, an improved result in distribution of the plastic through a finished article is obtained providing, of course, that proper quantities are used.

As can be seen in Figure 1 b, the plastic 12 employed has an affinity for the fibres tending to track the fibres, encapsulating and linking the fibres preferentially. This can and does, under appropriate conditions, provide a composite with small air spaces 1 3 creating a lightweight yet strong composite.

Referring now to Figure 2, there is illustrated typical apparatus 20 shown in schematic form and employing a fibre storage means 21 , a filler storage means

22 and a fibre/filler mixer 23 downstream of the storage means 21 and 22. The fibre held at 21 and the filler held at 22 can be pre-coated with, for example, lanolin and then delivered to the mixer. Alternatively, the lanolin can be applied at the mixer. In the illustrated embodiment, the blended fibre and filler is delivered to a bath where the lanolin coating can be applied along with other additives including a fire retardant such as alumina trihydrate or borax as described earlier. Typically, this bath is held at a temperature of 32°C, the coated fibre and filler then travels from the bath to a storage means at 25 where it can then be delivered to an extruder 26 or a mould 27a or 27b. In the illustrated embodiment, a two part resin is illustrated and typically includes polyol or amine components and in the illustrated embodiments polyol and isocyanate are either pre-mixed or delivered directly into the extruder or the mould forming, in each case, for example, an extruded poiyurethane fibre composite channel shown at 28 or a moulded poiyurethane fibre composite building panel shown at 29a or 29b.

In one typical process involving the use of sheepswool fibre, the production process involves the following. Wool/fibre will be carded or separated to loose individual fibres. Recycled paper and/or other filler material will be separated to a coarse pulp form. Where water/fire resistant products are required, the recycled paper or other filler material will be moved through a fire retardant oil bath and allowed time to permeate. Fibres other than naturally coated wool fibres will also receive the same treatment. The preferred oil product is lanolin.

Fibre and pulp will then be blended to the proportion required for the particular product.

After this, the fibre/pulp blend of material enters a controlled environment production area where it .typically enters a borax/water bath having a preferred temperature of 32° C. The material will then be allowed time to permeate in the bath. Typically, the material, after leaving the borax bath, will be delivered to the mixer where the fibre/pulp blend is placed on a perforated conveyor and passed over or through a steam vaporiser chamber to raise the temperature to a preferred 34° C prior to entering the chemical and fibre/pulp mixer.

The settable plastics chemical ingredients are drawn together from storage and batched into suitably sized production delivery tanks. In the case of a two part plastics, the two basic chemical ingredients are delivered to the mixer.

The fibre pulp and the chemical ingredients can be simultaneously blended at the mixer and then the material can be delivered to the extruder or to the mould as required.

In the case of an extruder, the extruder will carry the composite blend material from the mixing head to the mould or extrusion point, forcibly moved along an extrusion tube.

At the point of delivery, there are two product moulding process options as follows:- (i) delivery into the entry port of a product mould which is preferably fitted with a vacuum source to facilitate mould core filling; (ii) delivery into a product shaped extrusion tube/mould extended in length; or (iii) a mould is fitted with heating means to raise the temperature to

60°C - 80°C, preferably electrical resistance heating elements or hot water circulating jackets, so as to control the exotherm of chemical reaction and therefore accelerate the cure time. Some parts of the mould can be at a lower temperature where higher density is required. Other electrostatic variation can be used in order to vary density.

In the case of a moulding, the mould is electrostatically charged with, for example, a negative polarity and applied coatings and fillings charged with opposite positive polarity for automatic attraction. The use of electrostatic moulding and vacuum assist in combination with the enhancer improves the final outcome of the moulded product by providing a more intimate filling of the mould and distribution of the plastics material through the mould. In the case of moulded article, a release mould coating is first applied to the mould interior via electrostatic process. Where a pre-finished product is required from the mould, the colour coating is first applied, followed by the reinforced membrane coating, both applied by an electrostatic process. Typically, an ultra high voltage is applied during the application process so that the field has a curing effect on the coating particles immediately upon surface contact so as to speed up the whole process and facilitate a continuous process.

In a further preferred form, the blend is held at about 32°C during processing and 60°C to 80°C during product curing.

Referring now to Figure 3, a typical article, in this case a panel 30 is shown, the panel has a 3mm thick, relatively high density sheepswool reinforced external membrane 31 with a relatively low density sheepswool fibre reinforced composite core 32. A typical core 32 and/or panel may comprise a reinforced low density panel as suitable structural strength for erection in a building structure of the type illustrated in Figure 5. Passages for electrical, plumbing, telephone and/or other services are installed before the panel is made.

The structural integrity of the panel is improved by strengthening the marginal edges thereby confining the lightweight core material to a major portion of the central region of the panel. See, for example, Figure 4 where the membrane extends right around the panel being separated from the inner core 32 at the marginal edges by an intermediate density region 32a. This change in density may be a gradual change using electrostatic and/or cooler mould temperature processes.

Referring now to Figure 5, there is illustrated a further example of a process according to the invention involving a moulding step for preparation of a panel of the type illustrated in Figure 3. This involves the use of a mould body 33 configured to the shape of the panel illustrated in Figure 3, the mould includes a lid 34 hinged at 35 and as can be seen, blended raw materials at 36 are delivered into the mould, in this case, sheepswool via a venturi tube 37 while at the same time, a two part mix of settable plastics material, in this case, a poiyurethane or phenolic blend is delivered via a polymer nozzle 38 and catalyst nozzle 39 in sufficient proportions to adequately fill the mould when the lid 34 is closed and the settable plastics material has reacted and set in temperature controlled moulds.

The panels can be used in a building and one particular example is illustrated in Figure 6 which is a section showing a ground and first floor of a building employing interlocking floor and wall panels, all of which have been made using the process set out above. The panels interlock using the particular interlocking ends as illustrated in Figure 5. Once the panels have been assembled, a spray coating, as described previously, can be applied to the whole interior and across the joins between the interlocking panels and including exterior and/or over the top of the assembly either in part or in totality, thus providing a final overall coating to complete the assembly. It will be appreciated from the foregoing that by suitably strengthening the edges of the panels and the external coatings, that the panels can be made more or less structurally sound. Likewise, the present invention embraces rigid and flexible articles as well as composite or sandwich articles where parts of the articles are prepared from lighter, more flexible or more rigid parts as required.

A typical example of a lightweight core material involves a mixture forming a composite material from the following proportions at preparation:-

(i) wool/fibre content - 40% of total volume;

(ii) polymer content - 10% of total volume;

(iii) recycled paper or other filler content - 30% of total volume; and

(iv) water content - 20% of total volume. A more flexible material or a more semi-rigid material can be produced by varying the mixtures. Examples of mixtures toward the more flexible and more semi-rigid ends of the scale are as follows. A more flexible mixture requires a decrease of paper content and an increase of wool and polymer. For example the following proportions at preparation are typical:- (i) wool/fibre content from 52% to 53%;

(ii) polymer content from 12% to 13%;

(iii) recycled paper or other - 1 5%; and

(iv) water content - 20%.

A more semi-rigid mix requires an increase in paper and/or stock filler content and a decrease in wool content. For example the following proportions at preparation are typical :-

(i) wool/fibre content at about 25%;

(ii) polymer content at about 10%;

(iii) recycled paper or other at about 45%; and (iv) water content at about 20%.

The reinforced surface coating blend can vary according to the above specification, but optionally ceramic or cement powder and water are blended in one of a pair of mixing heads, with the other mixing heads blending the chemicals forming the settable plastics. The cement mix, polymer and chopped wool fibre are blended together in spray application after respective ingredients and/or compounds leave their respective nozzles in arranged sequence and are applied to, say, the interior of the building illustrated in Figure 6 using an electrostatic process. This results in a completely sealed join between panels as can be clearly seen in Figure 6 with a surface membrane about 2mm thick being typical and completes the product moulding process.

It will therefore be appreciated that whilst the above has been given by way of illustrative example of the present invention, many variations and modifications thereto will be apparent to those skilled in the art without departing from the broad ambit and scope of the invention as set forth in the appended claims.

Claims

1. An article forming process forming a fibre reinforced plastic article from naturally coated fibres or uncoated fibres using the chemical properties of those coated and/or uncoated fibres.

2. A process for forming material and/or a plastic material utilising the chemical properties of animal and/or other naturally grown or produced fibres.

3. A process for forming a material utilising the chemical properties of a wool fibre and/or its natural lanolin or other coating properties.

4. A process for forming a material utilising the chemical process created by the use of a synthetic and/or a natural fibre artificially or otherwise coated with lanolin and/or other material or synthetic fire retardant coating.

5. A process for forming a material utilising the chemical properties of lanolin additive or ingredient to promote additional fire resistant qualities to a material or a product.

6. A process for forming material utilising the chemical properties of lanolin coatings applied to natural and/or artificial or other fibres to enhance the fire retardant qualities of a material or a product.

7. A process according to any one of the preceding claims for forming a fibre reinforced plastic article from a blend of fibres and a settable plastic material, the article being formed while the blend is in a fluid or semi-fluid state and subsequently allowed to cure, the process comprising the steps of:-

(a) providing wool fibres either naturally coated or uncoated to plastic material to form a stable structural material;

(b) subsequently forming a blend of coated fibres with the settable plastic material;

(c) subsequently or simultaneously forming the article; and

(d) allowing the article to cure.

8. A process according to claim 7 wherein the coated fibres are pre-treated before the blending step, the pre-treatment being selected from the following:- (i) blending the coated fibres with auxiliary fibres or filler material;

(ii) the addition of water to the fibres as a fine spray or as steam;

(iii) preheating the fibres to a predetermined temperature desirable for article forming; (iv) addition of a fire retardant; or (v) pre-treating fibres by applying a finely dispersed or gaseous phase of lanolin.

9. A process according to claim 8 wherein the auxiliary fibres or filler material is coated with lanolin.

10. A process according to claim 8 wherein the addition of water includes application of steam.

1 1 . A process according to any one of the preceding claims wherein the fibres are coated by passing the fibre through a bath spray or gaseous dispersion containing lanolin.

12. A process according to any one the preceding claims wherein the article is coated with a coating, the coating being prepared according to step (a) and step (b), the coated fibres being from 1 mm to 10mm long and being employed in a blend having settable plastic content of about 1 5%, water content of about 1 5% and fibre content of about 70% by volume at preparation.

1 3. A process according to any one the preceding claims wherein the fibres are natural animal, vegetable or mineral fibres selected from the following:-

(i) Sheepswool or natural equivalent;

(ii) Cotton;

(iii) Jute;

(iv) Flax;

(v) Coconut; or

(vi) other natural, organic or mineral fibres and including mixtures of same.

14. The process according to any one of the preceding claims wherein the fibres are artificial fibres selected from the following:-

(i) Glass fibres;

(ii) Metal fibres; or

(iii) other artificial fibres including mixtures of same.

1 5. A process according to any one of the preceding claims including the addition of a refractive selected from the following:-

(i) Clay; and/or (ii) Cementitious material.

16. An apparatus for producing fibre reinforced plastics according to a process as set out in any one of the preceding claims.

1 7. The apparatus according to claim 16 comprising:-

(a) a coated fibre storage and delivery means;

(b) a settable plastics material storage and delivery means; and

(c) a blending and/or article forming means for receiving the coated fibres and simultaneously blending the fibres with the settable plastics material just prior to or during formation of the article.

18. The apparatus according to claim 16 or claim 1 7 wherein the apparatus employs heating means for raising the temperature of the coated fibres to a temperature desirable for the blending and article forming stage.

1 9. An assembly of separate articles according to the process of any one of the preceding claims wherein a surface coating or surface membrane is applied to the articles after assembly so that at least two of the articles share a common coating.

20. The assembly of claim 19 comprising a plurality of interlocking building panels where the coating is applied one-site to a structurally engineered thickness.

21 . The assembly of claim 1 9 or claim 20 wherein the interlocking building panels include a relatively lightweight interior core and interlocking marginal edge portions, the marginal edge portions being relatively dense and structurally reinforced.

22. An article made according to the process set out in any one of claims 1 to 15 wherein the article includes a relatively lightweight interior core and relatively dense surface coating or membrane.

23. An article according to claim 22 comprising a building panel having a relatively lightweight core, intermediate density marginal edge portion and a relatively dense surface membrane.

24. The building panel of claim 23 wherein the membrane is .5mm to 5mm thick.

25. The assembly according to claim 20 wherein the building panels are panels according to claim 23.

26. An article forming process for forming a fibre reinforced plastic article from a blend of fibres and a settable plastic material, the article being formed while the blend is in a fluid or semi-fluid state and subsequently allowed to cure, the process comprising the steps of:-

(c) subsequently or simultaneously forming the article; and

(d) allowing the article to cure.

27. The process according to claim 26 wherein the fibres are naturally coated sheepswool.

28. The process according to claim 26 or 27 wherein ceramic based material or cementitious material is added to the blend.

29. The process according to claim 26 or 27 wherein the coated fibres are pre- treated before the blending step, the pre-treatment being selected from the following:-

(i) blending the coated fibres with auxiliary fibres or filler material;

(ii) the addition of water to the fibres;

30. A process according to any one of the preceding claims wherein the article is coated with a coating, the coating being prepared according to step (a) and step (b), the coated fibres being from 1 mm to 10mm long or up to 50mm long and being employed in a blend having a settable plastic content of about 1 5%, water content of about 1 5% and fibre content of about 70% by volume at preparation.

31 . A process according to claim 26 wherein the fibres are natural animal, vegetable or mineral fibres selected from the following:-

(i) Sheepswool or natural equivalent; (ii) Cotton; (iii) Jute;