GB2480253A

GB2480253A - Method of forming a composite building product

Info

Publication number: GB2480253A
Application number: GB1007769A
Authority: GB
Inventors: Albertelli Aldino; Michael Frieh
Original assignee: Acell Group Ltd; VENEZIANI ACELL Srl
Current assignee: Acell Group Ltd
Priority date: 2010-05-10
Filing date: 2010-05-10
Publication date: 2011-11-16
Anticipated expiration: 2030-05-10
Also published as: GB201007769D0; GB2480253B

Abstract

The method, primarily for forming panels with masonry surface and other constructional/architectural components, comprises applying a porous substrate 10 to the first surface of a layer of sheet material 12 and a masonry the 14 to a second surface of the sheet material after which pressure is applied to press the layers together and form the composite product. A number of masonry tiles may be provided on the sheet material, between which grout or render may be provided. The sheet material may comprise a curable polymer material, preferably a thermosetting polymer resin matrix, which may include reinforcing fibres, preferably glass fibre. The substrate may comprise an open cell polymeric foam. A second layer of sheet material may be applied to the opposite side of the the to the first sheet material. The product may be provided with a tongue and groove arrangement or similar. Also claimed is a composite product.

Description

Composite products This invention relates to composite products having masonry surfaces and methods for producing such composite products. Preferred aspects of the invention relate to composite products having a brick, concrete, stone, tile or glass surface. Preferred aspects of the invention relate to composite products comprising a foam substrate and a masonry surface, such as a brick, concrete, stone, tile or glass surface, provided on the foam substrate. The composite products of the invention may be in the form of panels having masonry surfaces, for instance for use as construction materials and/or architectural components, although the invention has a wide range of potential applications.

Structures formed from masonry are traditionally constructed from masonry blocks which are generally laid in and bound together by mortar, in some cases with steel reinforcement. Such structures are generally highly durable, resistant to weathering, have good weight-bearing properties, and are also visually appealing, making masonry a widely-used construction material. However, masonry does have the disadvantages that masonry blocks are heavy, time-consuming to install, and can be extremely costly.

Particularly in the case of stone blocks, such as granite or marble, only a small portion of the costly stone is visible in use, making the use of entire blocks of such stone types unnecessary and economically prohibitive. Furthermore, traditional masonry construction techniques do not have the architectural flexibility that is found with more modern construction techniques, such as steel or concrete frame buildings. For instance, masonry construction techniques are generally unsuited to the construction of very tall buildings due to the weight of the masonry blocks.

There have been various efforts in the art to develop construction techniques which overcome the disadvantages of traditional masonry techniques, whilst maintaining the visual appeal and durability of traditional masonry in the completed structures.

Generally, these techniques involve some kind of masonry cladding or siding. The terms "cladding" and "siding" are used herein to refer to the application of a non-structural layer of masonry to a pre-existing structure, such as a wall or building, usually to imitate the appearance of a traditional masonry structure. The masonry layer is generally substantially thinner than traditional masonry building blocks, being required only for visual and non-structural purposes. Thus, siding materials often take the form of a tile or slip having the surface dimensions of a brick or stone block on the visible surface, but which are typically only 10 to 30 mm in depth.

Siding materials may be applied to structures by being embedded in a layer of mortar coating the surface of the structure, sometimes with the use of metallic or plastic guide rails, which are used to maintain even spacing of the siding materials, e.g. brick slips.

Another technique involves the use of metallic ties or clips which tie the siding materials to the underlying structure and which also transfer the weight of the siding materials to the building structure. Often metallic ties or clips and mortar are used in combination. If desired a pointing substance can subsequently be disposed in the spaces between the siding materials to complete the illusion of a traditional masonry structure.

The use of siding materials, whilst having some advantages over traditional masonry construction techniques, nonetheless has the disadvantage that the installation of large numbers of separate siding tiles remains comparatively times consuming. In addition, the need for the installation of the siding materials to take place entirely in situ can add significantly to the duration of construction projects.

An object of the present invention is to solve the above identified problems with the construction of masonry structures and/or structures having the visual impression of masonry structures. A further object of the invention is to provide improved composite products and methods of forming the improved composite products.

According to a first aspect of the invention, there is provided a method of forming a composite product, the method comprising: (i) providing a layer comprising a sheet-form material; (ii) providing a substrate including a porous structure; and (iii) providing a masonry tile; the method including the step of applying the substrate to a first surface of the sheet-form material, applying the masonry tile to a second surface of the sheet-form material, and applying pressure to press the masonry tile, the sheet-form material and the substrate together to form the composite product.

In this way, a composite product comprising a masonry surface can be formed. The masonry surface can provide a desirable aesthetic finish to the product and/or provide durability to the product.

As used herein, the term "masonry tile" is intended to refer to a tile formed, at least in part, from concrete, clay, natural stone, artificial stone, ceramic, glass, or a combination thereof. For example, the masonry tile may be formed from brick, marble, granite, limestone, travertine, sandstone, slate, cast stone, porcelain, earthenware, glass, or other similar materials, or a combination thereof. For the avoidance of doubt, as used herein, the term masonry tile should not be interpreted to include wood.

Where the masonry tile is formed from a porous material such as clay, porcelain or earthenware, it may be at least partially glazed. For example, the visible surface may be glazed, with the surface that contacts the sheet-form material remaining unglazed. As will be appreciated by persons of skill in the art, an unglazed surface provides a better key for attachment to the sheet-form material and is therefore preferable to form a strong bond.

The depth of the masonry tile is preferably less than 30 mm, more preferably less than 20 mm, and still more preferably less than 15 mm. Generally, a depth of at least 5 mm is preferred for reasons of durability, although with smaller masonry tiles the depth may be less than 5 mm, for example from 2 to 5 mm, e.g. 3 mm or 4 mm. Suitably, the masonry tile has a depth in the range of from 3 to 30 mm, more preferably 3 to 15 mm, for example 5to 15mm, or5to 10mm.

Generally, the surface area of the masonry tile will not be greater than about 500 mm by 500mm. However, the exact size of the masonry tile depends on the type of material used to form the masonry tile and the desired visual effect of the composite product. For instance, where the composite product is intended to look like a brick wall, the masonry tiles advantageously have a surface area of from about 190 to about 250 mm by about to about 75 mm to simulate the dimensions of a major side face of a standard building brick. Alternatively, the masonry tile may have a surface area of from about 95 to about mm by about 55 to about 75 mm to simulate the dimensions of an end face of a standard building brick. For example, the masonry tile could be cut from a standard building block, such as a standard building brick. Alternatively, the masonry tile could be a brick slip of the type known in the art.

In the United Kingdom a standard size building brick generally has a major side face of about 65 mm by about 215 mm and an end face of about 65 mm by about 102. 5 mm. In the United States a standard size building brick generally has a major side face of about 57 mm by about 203 mm and an end face of about 57 mm by about 102. 5 mm. Where the composite product is intended to look like a stone wall, a larger masonry tile size may be appropriate.

In a further embodiment, the masonry tile may comprise two surfaces which meet at an angle so as to simulate the corner of a masonry building block. For example, the surfaces may meet at substantially a right angle (i.e. 90°). In this embodiment, the sheet-form material and the substrate is desirably provided in a complementary shape to the surfaces of the masonry tile.

The surface of the masonry tile that contacts the sheet-form material may be provided with surface indentations or protrusions to form a key to ensure a strong bond is formed between the sheet-form material and the masonry tile. For example, a series of parallel or crossed grooves may be provided. In some cases, however, the masonry material may have a sufficiently coarse structure that the provision of surface indentations or protrusions is unnecessary for a strong bond to be formed between the sheet-form material and the masonry tile.

The masonry tile may extend over substantially all or only a part of the sheet-form material and/or the substrate area. Preferably, a plurality of masonry tiles is provided which collectively extend over substantially all or only a part of the sheet-form material and/or the substrate area. In this way, the plurality of masonry tiles may be rigidly bonded onto the surface of the sheet-form material and the substrate in any desired arrangement. For example, the plurality of masonry tiles may desirably arranged so as to imitate the arrangement of masonry building blocks found in traditional masonry construction techniques, for example the traditional brickwork bonds (e.g. Flemish bond, stretcher bond, English bond, header bond, herringbone bond and basket bond).

Optionally, the plurality of masonry tiles may be spaced apart and a rendering or grouting substance may be provided in the spaces between the masonry tiles to simulate the appearance of bricks bonded together by mortar, or a tiled wall or floor. Alternatively, a particulate material, such as sand, powdered brick, powdered stone or powdered ceramic, may be pressed into the sheet form material in the spaces between the masonry tiles to simulate the appearance of render or grout. Preferably, the particulate material is pressed into the sheet form material simultaneously with pressing of the masonry tile, the sheet form material and the substrate to form the composite product.

In accordance with the present invention, the sheet-form material preferably comprises a curable material, e.g. a curable polymer material.

Preferably, the sheet-form material comprises a thermosetting polymer resin matrix. For example,the thermosetting polymer resin matrix may be selected from polyester resins, vinyl ester resins, epoxy resins, phenolic resins, bismaleimide resins or polyimide resins.

Most preferably, the sheet-form material comprises a thermosetting polymer resin selected from polyester resins. The sheet-form material may also include melamine, which is useful as a fire retardant. The sheet-form material may further include additives selected from hardeners, accelerators, fillers, pigments, stabilizers, inhibitors, release agents, catalysts, thickeners, hydrating additives and/or any other components as required. The matrix may include a thermoplastic material.

The sheet-form material may comprise reinforcement, for example reinforcing fibres.

The fibres may include one or more materials. For example the fibres may include one or more of carbon fibres, glass fibres, aramid fibres and/or polyethylene fibres.

Preferably, the reinforcement comprises or consists of glass fibres.

The reinforcing fibres may be short fibres, for example having lengths of 5.0 cm or less, or may be longer fibres. The fibres may be loose, for example, the fibres may be arranged in a uni-or multi-directional manner. The fibres may be part of a network, for example woven or knitted together in any appropriate manner. The arrangement of the fibres may be random or regular, and may comprise a fabric, mat, felt or woven or other arrangement. Fibres may provide a continuous filament winding. Optionally, more than one layer of fibres may be provided.

Preferably the layer of sheet-form material comprises SMC (sheet moulding compound).

The SMC preferably includes a thermosetting polymer matrix as defined above and reinforcing fibres also as defined above. For example, the SMC may include a thermosetting resin, for example a polyester resin, together with reinforcing fibres, for example glass fibres. The thermosetting polymer may further comprise additives, for example minerals, inert fillers, pigments, stabilizers, inhibitors, release agents, catalysts, thickeners, hydrating additives and/or other suitable materials.

There are benefits in using SMC. For example, SMC has low density but favourable mechanical properties compared with other sheet-form materials, and also exhibits good thermal properties. Of particular importance for some applications, for example building applications, resistance to fire is good. SMC also shows good chemical resistance.

The sheet-form material may extend over substantially all or only a part of the substrate area. Preferably, the sheet-form material extends over substantially all of the substrate area.

The thickness of the sheet-form material may range from 0.5 mm to 10 mm, for example 1 mm to 5 mm. The thickness of the sheet-form material used depends on the type and weight of the masonry tile that is used. Generally an increased thickness of sheet-form material is preferred when heavier masonry tiles are used. The thickness of the sheet-form material may be obtained by using a single layer of sheet-form material having the required thickness, or by assembling a plurality of layers of sheet-form material until the required thickness is obtained. In addition, a mosaic of pieces of sheet-form material may optionally be used to extend over the substrate or a part thereof.

Alternatively or in addition to reinforcement being provided as an integral part of the sheet-form material, reinforcement may be provided as a separate layer, for example arranged between the sheet-form material and the substrate.

Where the separate layer of reinforcement is provided, it may be located across the whole of the substrate, or may for example be provided in only parts. For example, if there is a particular section of the product which is more susceptible to damage or attack, for example the corners of the composite product.

Preferably at least some part of curable material flows into a surface of the masonry tile during pressing. Preferably the material is keyed into the masonry tile. In this way, a strong bond between the matrix and the masonry tile can be obtained. More specifically, it is the curable material is pressed into grooves or around protrusions on the surface of the masonry tile, or into spaces in the coarse structure of the masonry tile, thus forming a strong bond between the sheet-form material and the masonry tile.

Alternatively or in addition, adhesive material may be applied between the sheet-form material and the masonry tile to aid bonding.

Preferably the configuration of the substrate is such that gas and/or vapour can be displaced from the pressing region. The pressing region is defined herein as that area where the surface of the substrate and the sheet-form material are being pressed together, preferably in the region of the interface of the substrate and the sheet-form material.

Preferably the nature of the surface of the substrate is such that the gas or vapour can escape from the pressing region. For example, at least a part of the surface of the material is preferably porous to allow for the displacement of gas or vapour from the pressing region.

Preferably the substrate is such that gas or vapour can escape from the pressing region in a direction having at least a component in a direction generally transverse to the pressing direction in which the sheet-form material is pressed to the substrate.

Other formations (as an alternative or in addition) may be provided to assist the displacement of the gas. For example, grooves or channels could be formed in the substrate.

The configuration of the substrate which allows for the displacement of the gas may be inherent in that it arises from the nature of the composition of the substrate itself, and/or it may be provided by subsequent action, for example by machining the substrate or by chemical action on the substrate.

Preferably the substrate includes a material having a cellular structure. A cellular structure of the substrate can provide the necessary displacement of the gases in some arrangements. In preferred examples, the substrate comprises a material including a substantially open-celled structure. In this way, good movement of the gases away from the pressing region can be obtained.

The substrate may comprise a foam material, wherein the foam material preferably has a substantially open-cell structure.

Preferably, the substrate is bonded to the sheet-form material during the pressing step.

In one embodiment, a curable material in the sheet-form material is pressed into the surface of the substrate during the pressing step, thus forming a strong mechanical bond between the components. More preferably, the curable material flows into the cells of the open-celled substrate during the pressing step. This can reduce the risk of delamination of the sheet-form material and the masonry tile from the substrate, provide a stable product when exposed to heating/cooling cycles and provides a monolithic composite structure without the need for an adhesive to be applied or the assembly of parts. In some cases it has been found that the bond achieved at the interface of the sheet-form material and the substrate is in fact stronger then the material of the substrate itself.

Alternatively, or in addition, an adhesive or other bonding agent may be used between the substrate and sheet-form material.

Thus, in a preferred embodiment, a curable material in the sheet-form material is pressed into the surface of the masonry tile and into the surface of the substrate during the pressing step.

By applying a sheet-form material to a substrate comprising an open-celled structure, several advantages can be achieved. In particular, by using an open cell foam substrate, air can pass into and through the open cell structure of the foam so that the risk of the air and gases leading to flaws and other deformities in the bond between the sheet-form material and the substrate is reduced.

Furthermore, by bonding the sheet-form material to the substrate and the masonry tile in the process of the invention, efficiencies in manufacture of the composite product can be achieved since a further step to adhere the components together can be avoided.

In principle, it is possible to use all previously described solid open-celled foam materials as the substrate. However, in aspects of the invention the solid open-cell foam is preferably a substantially rigid, self-supporting, open-cell polymeric foam which is resistant to deflection under load and does not collapse under moderate pressure. For example, the polymeric foam may be selected from phenolic resin foams, polystyrene foams, polyurethane foams, polyethylene foams, polyvinylchioride foams, polyvinylacetate foams, polyester foams polyether foams, and foam rubber. Preferably, the polymeric foam is selected from phenolic resin foams.

The solid open-cell foam may include a finely-divided particulate reinforcing material.

Suitable particulate reinforcing materials are preferably inert and insoluble. The reinforcing material may be present in an amount of up to 10 weight percent based on the total weight of the foam, for example from 2 to 10 weight percent, or 5 to 10 weight percent based on the total weight of the foam. Suitable reinforcing materials include organic or inorganic (including metallic) particulate materials, which may be crystalline or amorphous. Even fibrous solids have been found to be effective, although not preferred.

Non-limiting examples of suitable particulate materials include clays, clay minerals, talc, vermiculite, metal oxides, refractories, solid or hollow glass microspheres, fly ash, coal dust, wood flour, grain flour, nut shell flour, silica, mineral fibres such as finely chopped glass fibre and finely divided asbestos, chopped fibres, finely chopped natural or -10-synthetic fibres, ground plastics and resins whether in the form of powder or fibres, e.g. reclaimed waste plastics and resins, pigments such as powdered paint and carbon black, and starches.

Preferably the solid open-cell foam has a density in the range of 100 to 500 kgm3, more preferably 120 to 400 kgm3, and most preferably 120 to 250 kgm3.

The physical properties of such foams, especially the compressive strength and deflection under load are believed to be related to (amongst other factors) cell wall thickness and average cell diameter. Preferably, the average cell diameter of the solid open-cell foam is in the range of about 0.5 mm to 5 mm, more preferably 0.5 or 1 mm to 2 or 3 mm.

The cells or pores of the solid open-cell foam are open to the surface of the substrate which contacts the sheet-form material, and preferably they open out below the surface to a greater width than the opening, thereby providing an undercut which can enhance the keying of the sheet-form material to the foam.

The composite product produced according to the method of the invention may comprise, for example, a substrate in the form of a substantially planar panel having a thickness of from 0.5 to 20 cm. It will be appreciated that the exact thickness of the substrate panel is dependent on a number of factors, including the type of substrate, the type and thickness of the masonry tile(s) used, and the end use of the composite product. However, in some embodiments, it is preferred that the substrate panel has a thickness in the range of from 0.5 to 10 cm, more preferably 0.5 to 5 cm, still more preferably 0.5 to 3 cm, for example I to 3 cm.

By contrast, the surface dimensions of the substrate panel are not particularly limited and may vary widely depending on the end use of the composite product. -11 -

Preferably the substrate comprises a crushable material such that, during the application of pressure step, a surface of the substrate is moulded to the shape of the masonry tile(s).

The substrate may comprise a frangible material. Such a material may be rigid and non-crushable in the normal use of the resulting product, but during the pressing step, the substrate material can be crushed to mould the substrate to the shape of the masonry tile(s).

It is envisaged that the invention might be applied where the substrate comprises a material which is rigid even on the application of pressure, but preferably the substrate comprises a material which can be controllably crushed during application of pressure so that a surface of the substrate can take on the contours of a part of the mould.

In accordance with the present invention, the substrate preferably comprises a rigid foam, for example a foam material obtained by causing or allowing a mixture of phenolic resole, acid hardener and finely divided particulate solid to cure under conditions in which foaming for the mixture is caused primarily or solely by volatilisation of small molecules present in the resole or formed as a by-product of the curing reaction. The formation of an example of such foams is described in detail in EP 0010353 and foamed bodies comprising these foams can be obtained as ACELL foam from Acell Holdings Limited, UK.

The composite product produced may comprise for example a substrate panel having a "skin" of sheet-form material and masonry tile applied to one surface, or may comprise a substrate panel sandwiched between two skins.

Other arrangements are possible. In some cases, for example, the composite product may comprise a core having a first skin including sheet-form material and an outer layer of the masonry tile, and a second skin including just the sheet-form material and no masonry tile. This arrangement might be preferred where only one surface of the composite product is visible in use. -12-

Alternatively, the composite product may comprise a core having a first skin including sheet-form material and an outer layer of the masonry tile, and a second skin including sheet-form material the same or different masonry tile to the first skin.

The composite product having two skins may be formed in a single pressing operation as described above, wherein the required layers are arranged and then pressed together to bond the layers together. In this way, a two-sided composite product, such as a composite product panel, can be formed in a single pressing operation.

The components are pressed together between suitable pressing plates. In preferred examples, a pressing plate that contacts the masonry tile has one or more indentations or protrusions which maintain the desired position of the masonry tile(s) during the pressing step. For example, a pressing plate (or "former") may be used having a series of indentations or protrusions positioned so as to position the masonry tiles as in one of the traditional brickwork bonds identified above. The pressing plates are preferably metal, for example aluminium.

In a preferred embodiment, a particulate material as described above is provided on the pressing plate in spaces between the masonry tiles before the pressing step. During the pressing step, the particulate material is bonded to the sheet form material between the masonry tiles so as to simulate the appearance of render or grout.

Preferably the method includes applying heat and pressure to the masonry tile and the sheet-form material. Preferably, the sheet-form material is reduced in viscosity, and/or at least partially liquefies on the application of heat and/or pressure. In this way, some flow of the material can be achieved. Preferably, the material at least partly flows into cells of the substrate material during the pressing step.

The temperature required during the pressing step is dependent on the type of sheet form material used, the type of substrate, and the type of any adhesive which may be used, and can readily be determined by persons of skill in the art by routine experiment.

However, where the sheet form material comprises or consists of SMC, a temperature in the range of from 100 to 200 °C is appropriate, for example 120 to 160 °C. -13-

In a preferred embodiment, the masonry tile (and optionally any particulate material) is preheated prior to the pressing step. Preheating the masonry tile reduces the necessary duration of the pressing step, enabling a faster turnover of products. Any conventional means of preheating the masonry tile could be used, for example using hot air or infrared irradiation.

Preferably the sheet-form material is cured directly onto the masonry tile and substrate during the pressing operation. A broad aspect of the invention provides, curing a sheet of curable material directly onto the surface of a masonry tile and of a substrate, preferably a substrate configured to displace gas or vapour from the interface region, preferably the substrate comprising an open-cell foam.

Where the sheet-form material comprises a curable material, e.g. a thermosetting polymer, the method preferably includes the step of causing or allowing the material to cure. Preferably the pressure and temperature and cycle time are chosen so that the sheet-form material cures during the pressing operation.

Preferably the pressure applied is preferably in the range of from I to 20 kgcm3, more preferably 2 to 15 kgcm3, and most preferably 5 to 10 kgcm3.

Pressing of the composite material is preferably continued for a period of from 30 seconds to 20 minutes, for example 1 minute to 10 minutes.

To give improved rigidity, in the finished composite product (e.g. panel), a frame or frame members such as stiles, rails, and/or mullions may be provided within the composite product. The frame members may be of wood, metal (for example, aluminium) or plastics (such as uPVC) or a combination of these, e.g. metal-reinforced plastics. The plastics material may contain filler, if desired, to improve hardness and/or rigidity. In a preferred embodiment, the substrate occupies substantially the entire volume or volumes within the frame; i.e. substantially the whole space within a panel defined by first and second skins and the components of the frame.

-14 -The method of the invention may further comprise providing interconnecting means to enable a series of composite product panels according to the invention to be interconnected, e.g. to cover a wall or floor. In one preferred embodiment, the interconnecting means is a tongue and groove arrangement. For instance, the tongue and groove arrangement may be provided by profiling or machining the substrate.

In another embodiment, the method of the invention may comprise composite providing fixing means on the surface of the composite material panels which is opposite the masonry tile, wherein said fixing means are adapted to enable the composite product panel to be attached to a wall, frame or other surface. A variety of suitable fixing means are known in the art, and include metal clips.

In another aspect, the invention provides a product obtainable by a method as described herein.

In a further aspect, the invention provides a composite product comprising a substrate and a skin of sheet-form material bonded to a surface of the substrate, and further including a masonry tile bonded to a surface of the skin of sheet-form material.

Preferably, the substrate and/or the sheet-form material and/or the masonry tile are as described above.

The masonry tile may extend over substantially all or only a part of the sheet-form material and/or the substrate area. Preferably, a plurality of masonry tiles is provided which collectively extend over substantially all or only a part of the sheet-form material and/or the substrate area.

Similarly, the sheet-form material may extend over substantially all or only a part of the substrate area. Preferably, the sheet-form material extends over substantially all of the substrate area.

The composite product may comprise a reinforcing layer in addition to any reinforcement which may be present as part of the sheet-form material. For instance, the reinforcement -15-may be provided in the form of a layer located between the sheet-form material and the substrate. The reinforcing layer may be located across the whole of the substrate, or may for example be provided in only parts. For example, if there is a particular section of the product which is more susceptible to damage or attack, for example the corners of the composite product.

Preferably the sheet-form material is bonded to the masonry tile by way of a key. In this way, a strong bond between the matrix and the masonry tile can be obtained. More specifically, the sheet-form material may extend into grooves or around protrusions on the surface of the masonry tile, or into spaces in the coarse structure of the masonry tile, thus forming a strong bond between the sheet-form material and the masonry tile.

Alternatively or in addition, a layer of an adhesive material may be provided between the sheet-form material and the masonry tile.

Preferably, the sheet-form material extends into the surface of the substrate, thus forming a strong mechanical bond between the components. More preferably, a cured material extends into the cells of an open-celled substrate. This can reduce the risk of delamination of the sheet-form material and the masonry tile from the substrate, provide a stable product when exposed to heating/cooling cycles and provides a monolithic composite structure without the need for an adhesive to be applied or the assembly of parts. In some cases it has been found that the bond achieved at the interface of the sheet-form material and the substrate is in fact stronger then the material of the substrate itself.

In accordance with this aspect of the present invention, there is also provided a composite product comprising a substrate panel having a layer of sheet-form material bonded to a surface of the substrate panel, and further including a masonry tile bonded to a surface of the layer of sheet-form material. -16-

There is also provided a composite product comprising a substrate panel sandwiched between two layers of sheet-form material, wherein one or both layers of sheet-form material are bonded to a masonry tile.

The composite product (e.g. panel) may comprise a frame or frame members such as stiles, rails, and/or mullions. The frame members may be of wood, metal (for example, aluminium) or plastics (such as uPVC) or a combination of these, e.g. metal-reinforced plastics. The plastics material may contain filler, if desired, to improve hardness and/or rigidity. In a preferred embodiment, the substrate occupies substantially the entire volume or volumes within the frame; i.e. substantially the whole space within a panel defined by first and second skins and the components of the frame.

The composite product panels according to the invention may be provided with interconnecting means to enable a series composite product panels to be interconnected, e.g. to cover a wall or floor. In one preferred embodiment, the interconnecting means is a tongue and groove arrangement.

In another embodiment, the composite product panels according to the invention may be provided with fixing means on the surface of the composite material panels which is opposite the masonry tile, wherein said fixing means are adapted to enable the composite product panel to be attached to a wall, frame or other surface.

Where reference is made herein to for example the masonry tile, layer or substrate being bonded to another element, it is to be understood that, preferably, at least a part of the masonry tile, skin, layer or substrate is so bonded. In some examples, the masonry tile, layer or substrate will be attached over the whole of its interface with the other element.

As noted above, in aspects of the present invention, a suitable substrate is a solid open-cell phenolic resin foam. A particularly suitable substrate may be produced by way of a curing reaction between: (a) a liquid phenolic resole having a reactivity number (as defined below) of at least 1; and -17- (b) a strong acid hardener for the resole; optionally in the presence of: (c) a finely divided inert and insoluble particulate solid which is present, where used, in an amount of at least 5% by weight of the liquid resole and is substantially uniformly dispersed through the mixture containing resole and hardener; the temperature of the mixture containing resole and hardener due to applied heat not exceeding 85 °C and the said temperature and the concentration of the acid hardener being such that compounds generated as by-products of the curing reaction are volatilised within the mixture before the mixture sets such that a foamed phenolic resin product is produced.

By a phenolic resole is meant a solution in a suitable solvent of an acid-curable prepolymer composition prepared by condensation of at least one phenolic compound with at least one aldehyde, usually in the presence of an alkaline catalyst such as sodium hydroxide.

Examples of phenols that may be employed are phenol itself and substituted, usually alkyl substituted, derivatives thereof, with the condition that that the three positions on the phenolic benzene ring ortho-and para-to the phenolic hydroxyl group are unsubstituted. Mixtures of such phenols may also be used. Mixtures of one or more than one of such phenols with substituted phenols in which one of the ortho or para positions has been substituted may also be employed where an improvement in the flow characteristics of the resole is required. However, in this case the degree of cross-linking of the cured phenolic resin foam will be reduced. Phenol itself is generally preferred as the phenol component for economic reasons.

The aldehyde will generally be formaldehyde although the use of higher molecular weight aldehydes is not excluded.

The phenol/aldehyde condensation product component of the resole is suitably formed by reaction of the phenol with at least I mole of formaldehyde per mole of the phenol, the formaldehyde being generally provided as a solution in water, e.g. as formalin. It is -18-preferred to use a molar ratio of formaldehyde to phenol of at least 1.25 to I but ratios above 2.5 to I are preferably avoided. The most preferred range is 1.4 to 2.0 to 1.

The mixture may also contain a compound having two active hydrogen atoms (dihydric compound) that will react with the phenol/alciehyde reaction product of the resole during the curing step to reduce the density of cross-linking. Preferred dihydric compounds are diols, especially alkylene diols or diols in which the chain of atoms between the hydroxy groups contains not only methylene and/or alkyl-substituted methylene groups but also one or more heteroatoms, especially oxygen atoms. Suitable diols include ethylene glycol, propylene glycol, propane-1,3-diol, butane-1,4-diol and neopentyl glycol.

Particularly preferred diols are poly-, especially di-,(alkylene ether) diols, for example diethylene glycol and, especially, dipropylene glycol.

Preferably the dihydric compound is present in an amount of from 0 to 35% by weight, more preferably 0 to 25% by weight, based on the weight of phenol/aldehyde condensation product. Most preferably, the dihydric compound, when used, is present in an amount of from 5 to 15% by weight based on the weight of phenol/aldehyde condensation product. When such resoles containing dihydric compounds are employed in the present process, products having a particularly good combination of physical properties, especially strength, can be obtained.

Suitably, the dihydric compound is added to the formed resole and preferably has 2 to 6 atoms between OH groups.

The resole may comprise a solution of the phenol/aldehyde reaction product in water or in any other suitable solvent or in a solvent mixture, which may or may not include water.

Where water is used as the sole solvent, it is preferably present in an amount of from 15 to 35% by weight of the resole, preferably 20 to 30%. Of course the water content may be substantially less if it is used in conjunction with a cosolvent, e.g. an alcohol or one of the above-mentioned dihydric compounds where used. -19-

As indicated above, the liquid resole (i.e. the solution of phenol/aldehyde product optionally containing dihydric compound) must have a reactivity number of at least 1.

The reactivity number is lOIx where x is the time in minutes required to harden the resole using 10% by weight of the resole of a 66 to 67% aqueous solution of p-toluene sulfonic acid at 60 °C. The test involves mixing about 5m1 of the resole with the stated amount of the p-toluene sulfonic acid solution in a test tube, immersing the test tube in a water bath heated to 60 °C and measuring the time required for the mixture to become hard to the touch. The resole should have a reactivity number of at least I for useful foamed products to be produced and preferably the resole has a reactivity number of at least 5, most preferably at least 10.

The pH of the resole, which is generally alkaline, is preferably adjusted to about 7, if necessary, for use in the process, suitably by the addition of a weak organic acid such as lactic acid.

Examples of strong acid hardeners are inorganic acids such as hydrochloric acid, sulphuric acid and phosphoric acid, and strong organic acids such as aromatic sulphonic acids, e.g. toluene sulphonic acids, and trichloroacetic acid. Weak acids such as acetic acid and propionic acid are generally not suitable. The preferred hardeners for the process of the invention are the aromatic sulfonic acids, especially toluene sulfonic acids.

The acid may be used as a solution in a suitable solvent such as water.

When the mixture of resole, hardener and solid is to be poured, e.g. into a mould and in slush moulding applications, the amount of inert solid that can be added to the resole and hardener is determined by the viscosity of the mixture of resole and hardener in the absence of the solid. For these applications, it is preferred that the hardener is provided in a form, e.g. solution, such that when mixed with the resole in the required amount yields a liquid having an apparent viscosity not exceeding about 50 poises at the temperature at which the mixture is to be used, and the preferred range is 5 to 20 poises.

Below 5 poises, the amount of solvent present tends to present difficulties during the curing reaction.

-20 -The curing reaction is exothermic and will therefore of itself cause the temperature of the mixture containing resole and acid hardener to increase. The temperature of the mixture may also be raised by applied heat, but the temperature to which said mixture may then be raised (that is, excluding the effect of any exotherm) preferably does not exceed 85 °C. If the temperature of the mixture exceeds 85 °C before addition of the hardener, it is usually difficult or impossible thereafter to properly disperse the hardener through the mixture because of incipient curing. On the other hand, it is difficult, if not impossible, to uniformly heat the mixture above 85 °C after addition of the hardener.

Increasing the temperature towards 85 °C tends to lead to coarseness and non-uniformity of the texture of the foam but this can be offset at least to some extent at moderate temperatures by reducing the concentration of hardener. However at temperatures much above 75 °C even the minimum amount of hardener required to cause the composition to set is generally too much to avoid these disadvantages. Thus, temperatures above 75 °C are preferably avoided and preferred temperatures for most applications are from ambient temperature to about 75 °C. The preferred temperature range usually depends to some extent on the nature of the particulate solid, where used.

For most solids the preferred temperature range is from 25 to 65 °C, but for some solids, in particular wood flour and grain flour, the preferred temperature range is 25 to 75 °C.

The most preferred temperature range is 30 to 50 °C. Temperatures below ambient, e.g. down to 10 °C can be used if desired, but no advantage is usually gained thereby. In general, at temperatures up to 75 °C, increase in temperature leads to decrease in the density of the foam and vice versa.

The amount of hardener present also affects the nature of the product as well as the rate of hardening. Thus, increasing the amount of hardener not only has the effect of reducing the time required to harden the composition, but above a certain level dependant on the temperature and nature of the resole it also tends to produce a less uniform cell structure. It also tends to increase the density of the foam because of the increase in the rate of hardening. In fact, if too high a concentration of hardener is used, the rate of hardening may be so rapid that no foaming occurs at all and under some conditions the reaction can become explosive because of the build up of gas inside a hardened shell of resin. The appropriate amount of hardener will depend primarily on the -21 -temperature of the mixture of resole and hardener prior to the commencement of the exothermic curing reaction and the reactivity number of the resole and will vary inversely with the chosen temperature and the reactivity number. The preferred range of hardener concentration is the equivalent of 2 to 20 parts by weight of p-toluene sulfonic acid per 100 parts by weight of phenol/aldehyde reaction product in the resole assuming that the resole has a substantially neutral reaction, i.e. a pH of about 7. By equivalent to p-toluene sulfonic acid, it is meant that the amount of hardener required to give substantially the same curing time as the stated amount of p-toluene sulfonic acid. The most suitable amount for any given temperature and combination of resole and finely divided solid is readily determinable by simple experiment. Where the preferred temperature range is 25 to 75 °C and the resole has a reactivity number of at least 10, the best results are generally obtained with the use of hardener in amounts equivalent to 3 to 10 parts of p-toluene sulfonic acid per 100 parts by weight of the phenol/aldehyde reaction product. For use with temperatures below 25 °C or resoles having a reactivity number below 10, it may be necessary to use more hardener.

By suitable control of the temperature and of the hardener concentration, the time lapse between adding the hardener to the resole and the composition becoming hard (referred to herein as the curing time) can be varied at will from a few seconds to up to an hour or even more, without substantially affecting the density and cell structure of the product.

Another factor that controls the amount of hardener required can be the nature of the inert solid, where present. Very few are exactly neutral and if the solid has an alkaline reaction, even if only very slight, more hardener may be required because of the tendency of the filler to neutralize it. It is therefore to be understood that the preferred values for hardener concentration given above do not take into account any such effect of the solid. Any adjustment required because of the nature of the solid will depend on the amount of solid used and can be determined by simple experiment.

The exothermic curing reaction of the resole and acid hardener leads to the formation of by-products, particularly aldehyde and water, which are at least partially volatilised.

The curing reaction is effected in the presence of a finely divided inert and insoluble -22 -particulate solid which is substantially uniformly dispersed throughout the mixture of resole and hardener. By an inert solid it is meant that in the quantity it is used it does not prevent the curing reaction.

It is believed that the finely divided particulate solid provides nuclei for the gas bubbles formed by the volatilisation of the small molecules, primarily formaldehyde and/or water, present in the resole and/or generated by the curing action, and provides sites at which bubble formation is promoted, thereby assisting uniformity of pore size. The presence of the finely divided solid may also promote stabilization of the individual bubbles and reduce the tendency of bubbles to agglomerate and eventually cause likelihood of bubble collapse prior to cure. To achieve the desired effect, the solid should be present in an amount of not less than 5% by weight based on the weight of the resole.

Any finely divided particulate solid that is insoluble in the reaction mixture is suitable, provided it is inert. Examples of suitable particulate solids are provided above.

Solids having more than a slightly alkaline reaction, e.g. silicates and carbonates of alkali metals, are preferably avoided because of their tendency to react with the acid hardener.

Solids such as talc, however, which have a very mild alkaline reaction, in some cases because of contamination with more strongly alkaline materials such as magnesite, are

acceptable.

Some materials, especially fibrous materials such as wood flour, can be absorbent and it may therefore be necessary to use generally larger amounts of these materials than non-fibrous materials, to achieve valuable foamed products.

The solids preferably have a particle size in the range 0.5 to 800 microns. If the particle size is too great, the cell structure of the foam tends to become undesirably coarse. On the other hand, at very small particle sizes, the foams obtained tend to be rather dense.

The preferred range is I to 100 microns, most preferably 2 to 40 microns. Uniformity of cell structure appears to be encouraged by uniformity of particle size. Mixtures of solids may be used if desired.

-23 -If desired, solids such as finely divided metal powders may be included which contribute to the volume of gas or vapour generated during the process. If used alone, however, it be understood that the residues they leave after the gas by decomposition or chemical reaction satisfy the requirements of the inert and insoluble finely divided particulate solid required by the process of the invention.

Preferably, the finely divided solid has a density that is not greatly different from that of the resole, so as to reduce the possibility of the finely divided solid tending to accumulate towards the bottom of the mixture after mixing.

One preferred class of solids is the hydraulic cements, e.g. gypsum and plaster, but not Portland cement because of its alkalinity. These solids will tend to react with water present in the reaction mixture to produce a hardened skeletal structure within the cured resin product. Moreover, the reaction with the water is also exothermic and assists in the foaming and curing reaction. Foamed products obtained using these materials have particularly valuable physical properties. Moreover, when exposed to flame even for long periods of time they tend to char to a brick-like consistency that is still strong and capable of supporting loads. The products also have excellent thermal insulation and energy absorption properties. The preferred amount of inert particulate solid is from 20 to 200 parts by weight per 100 parts by weight of resole.

Another class of solids that is preferred because its use yields products having properties similar to those obtained using hydraulic cements comprises talc and fly ash. The preferred amounts of these solids are also 20 to 200 parts by weight per 100 parts by weight of resole.

For the above classes of solid, the most preferred range is 50 to 150 parts per 100 parts of resole.

In general, the maximum amount of solid that can be employed is controlled only by the physical problem of incorporating it into the mixture and handling the mixture. In general it is desired that the mixture is pourable but even at quite high solids concentrations, -24 -when the mixture is like a dough or paste and cannot be poured, foamed products with valuable properties can be obtained.

Other additives may be included in the foam-forming mixture; e.g. surfactants, such as anionic materials e.g. sodium salts of long chain alkyl benzene sulfonic acids, non-ionic materials such as those based on poly(ethyleneoxide) or copolymers thereof, and cationic materials such as long chain quaternary ammonium compounds or those based on polyacrylamides; viscosity modifiers such as alkyl cellulose especially methyl cellulose, and colorants such as dyes or pigments. Plasticisers for phenolic resins may also be included provided the curing and foaming reactions are not suppressed thereby, and polyfunctional compounds other than the dihydric compounds referred to above may be included which take part in the cross-linking reaction which occurs in curing; e.g. di-or poly-amines, di-or poly-isocyanates, di-or poly-carboxylic acids and aminoalcohols.

Polymerisable unsaturated compounds may also be included possibly together with free-radical polymerisation initiators that are activated during the curing action e.g. acrylic monomers, so-called urethane acrylates, styrene, maleic acid and derivatives thereof, and mixtures thereof. The foam-forming compositions may also contain dehydrators, if desired.

Other resins may be included e.g. as prepolymers which are cured during the foaming and curing reaction or as powders, emulsions or dispersions. Examples are polyacetals such as polyvinyl acetals, vinyl polymers, olefin polymers, polyesters, acrylic polymers and styrene polymers, polyurethanes and prepolymers thereof and polyester prepolymers, as well as melamine resins, phenolic novolaks, etc. Conventional blowing agents may also be included to enhance the foaming reaction, e.g. low boiling organic compounds or compounds which decompose or react to produce gases.

The SMC may be prepared, for example, by applying a layer of a resin paste, for example a polyester resin paste, containing additives where appropriate, onto a bottom film carrier. Glass fibres as the reinforcement are then applied to the upper surface of the resin paste on the film carrier. A further layer of the resin paste is applied to sandwich the fibres between the layers of matrix. A top film is applied to the upper layer of the matrix. The resulting layered composition is subsequently compressed using a -25 -series of rollers to form a sheet of the sheet moulding compound between the film carriers. The material is rolled onto rollers and kept for at least 3 days at a regulated temperature of for example 23 to 27 °C. The resulting SMC can be compression moulded with heat. The shelf life of the SMC before use is usually a few weeks.

Figure 1 shows an exploded cross-sectional view of the components of the composite product according to the present invention prior to being pressed. The components shown are a substrate (10), a layer of sheet-form material (12) and a masonry tile (14).

Figure 2 shows a schematic cross-sectional view of the components shown in Figure 1 following pressing to form the composite product of the invention.

Figure 3 shows a schematic cross-sectional view of a composite product according to the invention, wherein a masonry tile (16) having two surfaces meeting at a right angle is bonded to a complementary substrate (18) by the sheet-form material (12).

Figure 4 shows a schematic plan view of a composite product according to the invention comprising a plurality of masonry tiles (20) bonded to a single substrate surface.

Figure 5 shows a schematic cross-sectional view of a composite product according to the invention comprising a plurality of masonry tiles (20) bonded to a single substrate surface and a particulate material (22) bonded to the sheet form material (12) in the spaces between the tiles, which particulate material simulates the appearance of render or grout.

In an exemplary process according to the invention, a plurality of masonry tiles formed from brick (brick slips) and having a depth of 10 to 15 mm are positioned in an aluminium former having protrusions and/or indentations to maintain the masonry tiles in the shape of a desired brickwork bond. Spaces between the brick slips are filled with sand of desired colour and the resulting assembly is preheated to 120 to -26 - 00. A layer of SMC is laid on top of the brick slips and sand, and a layer of a solid open-cell phenolic resin foam is laid on top of the SMC, followed by a second layer of SMC. A pressing plate heated to 120 to 160 °C is positioned on the second layer of SMC and the resulting assembly is pressed using 2 to 10 kgcm2 of pressure for a period of from 2 to 10 minutes.

Claims

-27 -CLAIMS1. A method of forming a composite product, the method comprising: (i) providing a layer comprising a sheet-form material; (ii) providing a substrate including a porous structure; and (iii) providing a masonry tile; the method including the step of applying the substrate to a first surface of the sheet-form material, applying the masonry tile to a second surface of the sheet-form material, and applying pressure to press the masonry tile, the sheet-form material and the substrate together to form the composite product.
2. A method according to Claim 1, wherein the masonry tile is formed, at least in part from concrete, clay, natural stone, artificial stone, ceramic, glass, or a combination thereof.
3. A method according to Claim 2,wherein the masonry tile is formed, at least in part from brick, marble, granite, limestone, travertine, sandstone, slate, cast stone, porcelain, earthenware, glass, or a combination thereof.
4. A method according to any one of the preceding claims, wherein the masonry tile is partially glazed.
5. A method according to any one of the preceding claims, wherein masonry tile has a depth in the range of from 3 to 30 mm.
6. A method according to any one of the preceding claims wherein the masonry tile has a surface area of from 190 to 250mm by 55 to 75mm.
7. A method according to any one of Claims 1 to 5, wherein the masonry tile has a surface area of from 95 to 125mm by 55 to 75 mm.
8. A method according to any one of the preceding claims, wherein the masonry tile comprises two surfaces which meet at an angle.

-28 -
9. A method according to any one of the preceding claims, wherein the masonry tile is provided with surface indentations or protrusions on the surface that contacts the sheet-form material.
10. A method according to any one of the preceding claims, wherein a plurality of masonry tiles is provided which collectively extends over substantially all or only a part of the sheet-form material and/or the substrate area.
11. A method according to Claim 10, wherein a rendering or grouting substance is provided in the spaces between adjacent masonry tiles.
12. A method according to any one of the preceding claims, wherein the sheet-form material comprising a curable polymer material, preferably a thermosetting polymer resin matrix.
13. A method according to Claim 12, wherein the thermosetting polymer resin matrix is selected from polyester resins, vinyl ester resins, epoxy resins, phenolic resins, bismaleimide resins or polyimide resins.
14. A method according to any one of the preceding claims, wherein the sheet-form material comprises reinforcement, such as reinforcing fibres.
15. A method according to Claim 14, wherein the reinforcing fibres comprise or consist of glass fibres.
16. A method according to Claim 12, wherein the sheet-form material comprises sheet moulding compound (SMC).
17. A method according to any one of the preceding claims, wherein the sheet-form material extends over substantially all of the substrate area.

-29 -
18. A method according to any one of the preceding claims, wherein the sheet-form material has a thickness in the range of from 0.5 mm to 10 mm.
19. A method according to any one of the preceding claims wherein at least part of the substrate surface is porous.
20. A method according to Claim 19, wherein the substrate includes a material having a cellular structure, more preferably an open-cell structure.
21. A method according to Claim 20, wherein the substrate comprises an open-cell foam.
22. A method according to Claim 21, wherein the substrate comprises a substantially rigid, self-supporting, open-cell polymeric foam which is resistant to deflection under load and does not collapse under moderate pressure.
23. A method according to Claim 22, wherein the open-cell polymeric foam is selected from phenolic resin foams, polystyrene foams, polyurethane foams, polyethylene foams, polyvinylchloride foams, polyvinylacetate foams, polyester foams polyether foams, and foam rubber.
24. A method according to Claim 22 or Claim 23, wherein the open-cell polymeric foam includes a finely-divided particulate reinforcing material.
25. A method according to any one of Claims 21 to 24, wherein the open-cell foam has a density in the range of 100 to 500 kgm3.
26. A method according to any one of Claims 21 to 25, wherein the open-cell foam has an average cell diameter of 0.5 mm to 5 mm.

-30 -
27. A method according to any one of the preceding claims, wherein the substrate is in the form of a substantially planar panel having a thickness of from 0.5 to cm.
28. A method according to Claim 27, further comprising applying a second layer of sheet-form material to the surface of the substrate panel opposite the first layer of sheet-form material before the pressing step.
29. A method according to Claim 28, further comprising applying a second masonry tile to the second layer of sheet-form material before the pressing step.
30. A method according to any of the preceding claims, further comprising providing interconnecting means to enable a series of composite product panels according to the invention to be interconnected, such as a tongue and groove arrangement.
31. A method according to any of the preceding claims, wherein the pressure applied during the pressing step is in the range of from ito 20 kgcm3.
32. A method according to any of the preceding claims, further comprising heating the composite material to a temperature of from 100 to 200 °C during the pressing step.
33. A method according to any of the preceding claims, further comprising preheating the masonry tile prior to the pressing step.
34. A composite product obtainable by a method according to any one of Claims 1 to 33.
35. A composite product comprising a substrate and a skin of sheet-form material bonded to a surface of the substrate, and further comprising a masonry tile -31 -bonded to a surface of the skin of sheet-form material.
36. A composite product according to Claim 35, wherein the masonry tile is as defined in any one of Claims 2 to 9.
37. A composite product according to Claim 35 or Claim 36, wherein the sheet-form material is as defined in any one of Claims 12 to 18.
38. A composite product according to any one of Claims 35 to 37, wherein the substrate is as defined in any one of Claims 19 to 27.
39. A composite product according to any one of Claims 35 to 38, wherein a plurality of masonry tiles collectively extends over substantially all of the sheet-form material and/or the substrate area.
40. A composite product according to any one of Claims 35 to 39, comprising a substrate panel having a layer of sheet-form material bonded to a surface of the substrate panel, and further comprising a masonry tile bonded to a surface of the layer of sheet-form material.
41. A composite product according to Claim 40, comprising a substrate panel sandwiched between two layers of sheet-form material, wherein one or both layers of sheet-form material are bonded to a masonry tile.
42. A composite product according to Claim 40 or Claim 41, further comprising interconnecting means to enable a series composite product panels to be interconnected, for example a tongue and groove arrangement.
43. A composite product according to any one of Claims 40 to 42, further comprising fixing means on the surface of the composite material panel which is opposite the masonry tile, wherein said fixing means are adapted to enable the composite product panel to be attached to a wall, frame or other surface.