Composite product with surface effect

Abstract

The present invention relates to methods of manufacturing composite products having a surface effect. In some examples described, a composite product has a simulated surface, for example a stone-effect surface formed by pressing a particulate-form surface material (30) and a sheet-form curable material (40) onto a substrate (44) having an open-celled structure. In other examples, a laminate product having a veneer is formed by pressing a veneer and a sheet-form material onto a substrate including a porous structure. The veneer may comprise a wood material. In other examples, a surface effect material is bonded to a skin by pressing a sheet-form curable material to a mold surface and the surface effect material. Where the surface effect material has a high thermal conductivity, the composite product formed can feel cool to the touch.

Claims

1. A method of forming a composite product with a skin having a surface effect, the method comprising: providing a substrate including a substantially open-celled foam material; providing a sheet comprising curable material; providing a surface material in particulate form; associating the particulate surface material with the sheet comprising curable material; associating the sheet comprising curable material associated with the particulate surface material with the substrate having a substantially open-celled foam; and pressing the sheet comprising curable material associated with the particulate surface material and the substrate with a press such that during the pressing the sheet comprising curable material cures and becomes bonded to the substrate and the particulate surface material becomes at least partially embedded in an exposed surface of the sheet comprising curable material.

2. A method according to claim 1, wherein at least a part of the surface material is exposed at the surface of the skin to form a textured surface.

3. A method according to claim 1, wherein the surface effect is applied to a surface effect region of the substrate, and prior to the pressing step the sheet comprising curable material extends substantially continuously across the surface effect region.

4. A method according to claim 1, wherein prior to pressing the sheet comprising curable material extends over substantially all of a surface of the substrate.

5. A method according to claim 1, wherein the surface material includes two different materials, and the step of associating the particulate surface material comprises applying a first surface material in relation to a first region of the substrate and applying a second surface material in relation to a second region of the substrate.

6. A method according to claim 1 wherein the size of the particles of the surface material is such that at least 50% by weight of the particles have a size of at least 0.5 mm.

7. A method according to claim 6, wherein the size of the particles of the surface material is such that at least 70% by weight of the particles have a size of at least 0.5 mm.

8. A method according to claim 6, wherein the size of the particles of the surface material is such that at least 50% by weight of the particles have a size of at least 1.0 mm.

9. A method according to claim 1, wherein the pressing is carried out in a single step to form the composite product.

10. A method according to claim 1, wherein the skin has a simulated stone surface.

11. A method according to claim 1, the method further comprising providing a contoured substrate surface, and pressing the sheet comprising curable material onto the contoured surface.

12. A method according to claim 11, wherein the surfacing material has a dimension that is at least the depth of the contours of the surface, thereby allowing for the press to contact a flat surface when forming the composite product.

13. A method according to claim 1, further comprising a step of carrying out a surface treatment to increase exposure of the particulates in the surface.

14. A method according to claim 1, wherein the particulates include sand.

15. A method according to claim 1, wherein the sheet comprising curable material comprises a sheet molding compound (SMC).

16. A method according to claim 1, wherein the substrate includes surface formations for keying with the curable material.

17. A method according to claim 1, wherein the method further comprises the step of providing a second layer including a sheet comprising curable material over the substrate, the substrate being sandwiched between the first and second layers of sheet comprising curable material, and pressing the second layer and the substrate together.

18. The method of claim 17, further comprising a step of spreading the particulates of surface material across the second layer including a sheet comprising curable material.

19. A method according to claim 1, wherein the substrate comprises a crushable material such that, during the pressing step, a surface of the substrate is molded.

20. A method according to claim 1, wherein the substrate comprises a frangible material.

21. A method according to claim 1 wherein the surface material is heated prior to the pressing step.

22. A method according to claim 1 wherein the method further comprises steps of: arranging a base member and applying a layer of the surface material over the base member; positioning the sheet comprising curable material over the layer of surface material; arranging the substrate over the sheet comprising curable material; and pressing the substrate towards the base member to form the composite product.

23. A method according to claim 1, wherein pressing the sheet comprising curable material associated with the particulate surface material and the substrate against a molding surface and the method further comprises a step of separating the composite product from the molding surface.

Description

(1) Preferred features of the present invention will now be described, purely by way of example, with reference to the accompanying drawings, in which:

(2) FIG. 1 shows a schematic plan view of a mould used for forming a skin according to an example of the present invention;

(3) FIG. 2 shows a section taken on A-A of FIG. 1 and showing schematically the components for moulding a laminate product including the simulated stone skin;

(4) FIG. 3 shows the layers in a method for moulding a wall panel;

(5) FIGS. 4a and 4b show steps in forming three dimensional article using a method of the present invention;

(6) FIGS. 5a to 5c show steps in an example of forming a composite product having a contoured surface;

(7) FIG. 6 shows a schematic plan view of a mould used for forming a laminate product according to an example of an aspect of the present invention;

(8) FIG. 7 shows a section taken on A-A of FIG. 6 and showing schematically the veneer and moulding material;

(9) FIG. 8 illustrates in perspective exploded view the moulding of a laminated composite;

(10) FIG. 9 shows in schematic sectional view the components of a door.

(11) FIG. 10 shows a schematic plan view of a mould used for forming a skin according to an example of an aspect of the present invention;

(12) FIG. 11 shows a section taken on A-A of FIG. 10 and showing schematically the components for moulding a laminate product including the simulated effect surface; and

(13) FIG. 12 shows the layers in a method for moulding a wall panel having a cool touch surface.

(14) In a method described in UK Patent Application No. 0719343.6, the skins are bonded directly to a foam core during a moulding step. A layer of sheet-form SMC is provided on the mould surface, a foam core is placed on the layer of SMC, and pressure is applied to mould the components together. During the moulding step, the core and SMC layer are moulded to the desired shape, and the SMC material becomes bonded to the core. The content of that patent application is incorporated herein by reference.

(15) FIG. 1 shows schematically a plan view of an aluminium mould 20. The mould comprises a surface contour suitable for moulding a simulated sandstone panel. The moulding surface is rectangular and includes a pattern of projections 22 arranged to emulate the position of gaps between adjacent blocks of a sandstone wall.

(16) The mould is heated to a temperature of approximately 140 degrees C.

(17) Sharp sand is dusted over the surface of the mould to form a granular layer 30.

(18) As shown in FIG. 2, a sheet of sheet moulding compound 40 is applied to the upper surface of the mould over the granular layer 30. The sheet 40 is sized so as to extend across the whole area of the mould surface 20.

(19) It will be appreciated that in FIG. 2 and in other of the figures the shapes of the components are shown schematically. In particular, the relative thicknesses of the elements are not shown to scale. For example, the preferred thickness of the SMC is about 1 mm whereas the thickness of the substrate is about 5 cm.

(20) Onto the sheet 40 is placed a wooden frame 42 is positioned onto the sheet 40 (FIG. 2) and a block of foam substrate 44 is inserted into the frame 42.

(21) The substrate 44 may comprise a foam, for example as described in more detail below.

(22) Such foam used is advantageously: structural and has significant load bearing properties frangible and can be formed under pressure and has no memory and therefore substantially retains its pressed form open cell and therefore allows the migration of clues resins into the cells during door manufacture to create a truly monolithic composite structure.

(23) In an example of the foam used, the cell size ranges from 0.5 to 3 mm and the density is 80 to 800 kg/m3.

(24) The block of foam 44 is sized so as to be thicker than the frame so that the upper surface of the foam 44 extends above the frame 42 when the foam 44 is inserted in the aperture of the frame 42.

(25) Downward pressure of about 100 tonnes is applied to the components (as arranged in FIG. 3) using a pressure plate 50. The substrate 44 is pressed toward the lower moulding surface 20, crushing the foam and moulding the lower surface of the substrate to the shape of the mould surface 20. The SMC sheet 40 is also pressed between the mould surface and the substrate 44. Near the heated mould surface 20, the SMC begins to liquefy and flows into cells at the surface of the substrate 44 as well as around the grains of the sand to encapsulate the sand into its surface.

(26) Air and other gases trapped between the SMC 40 and the substrate 44 passes through the open cell structure of the foam. The components are held in the mould with the application of pressure for a sufficient time for the SMC to cure for form a skin bound to the moulded substrate 44.

(27) The resulting product is removed from the mould. The cycle time for moulding the product may be about 4 minutes.

(28) It is seen that in this example, an upper mould portion is not required. In this example, the components are pressed against a single heated platen.

(29) A moulded panel having a simulated stone surface may be formed in a single pressing step.

(30) A lower mould 20 is provided and placed on a heated platen 25 so that the mould reaches a temperature of about 140 degrees C. The lower moulding surface 21 of the lower mould 20 may be flat or may be contoured as here according to the surface shape of a stone wall.

(31) A layer of granular material 30, here sand is placed onto the moulding surface 21.

(32) A sheet 40 of curable material is applied. The size of the lower sheet 40 is approximately the same as that of the lower moulding surface 21.

(33) A foam block 44 comprising ACELL foam is applied to the upper surface of the lower sheet 40. A wooden frame 42 is placed around the lower foam block. Alternatively, the frame 42 could be applied first, and the block 44 inserted into the frame. A reinforcement sheet 46 comprising a metal grid is placed in the frame 42 onto the lower foam block 44. Onto the reinforcement sheet 46 and within the frame 42 is placed an upper foam block 48 also comprising ACELL foam. A layer of adhesive may be applied between the two blocks 44, 48 to aid bonding. Onto the upper foam block is placed the upper sheet 52 of curable material.

(34) Optionally, onto the upper sheet of curable material 52 is placed further granular material, for example sand 54. In some arrangements, it will be desired for the simulated sandstone surface to be present on both surfaces of the panel. In other arrangements, sandstone on one surface of the door only will be required. In the latter case, it will be appreciated that the granular material may be arranged at the lower or the upper region of the moulded components. In other words, the order of laying down of the components shown in FIG. 3 may be reversed.

(35) An upper mould 56 is provided having an upper moulding surface 58 contoured according to the surface shape of a wall panel or flat as shown here. The upper mould 56 is heated to a temperature of about 140 degrees C.

(36) The upper mould 56 is lowered onto the other components and pressure of about 100 tonnes is applied to press the upper mould 56 towards the lower mould 20.

(37) The upper block 48 and the lower block 44 comprise frangible foam and the surfaces of the blocks facing the adjacent mould surfaces 20 and 58 are crushed and moulded to the surface shape of the wall panel.

(38) The curable material of the upper and lower sheets 40 and 52 flow into the adjacent foam blocks 44, 48 and also around the grains of sand to form a mechanical bond. Curing of the curable material takes place in the heated mould so that the upper and lower sheets 40 and 52 form skins bonded to the upper and lower blocks.

(39) Once cure is complete after a few minutes, the formed panel is released from the mould.

(40) Thus it can be seen how a panel can be made in a single pressing operation.

(41) In an alternative example, the lower block 44, the reinforcement 46 and the upper block 48 are provided as a single unit.

(42) In other arrangements, the mould may be coated with a powder coating which then forms a coating on the product. This feature may be present in relation to any of the aspects of the invention. As an example, a powder coating can be applied electrostatically to the mould surface. Where the mould surface is heated, the powder coating melts or softens almost as soon as it is applied to the surface. For example the powder may include a polyester. The SMC or other matrix material (with or without integral reinforcing material) is then applied over the melted or softened powder coating. The melted or softened powder coating is then sticky on the surface of the mould and is thought to reduce movement of the matrix material during the moulding operation, which can in some cases give improved surface finish. In this example, the coating remains on the surface of the product, and provides a surface which is scratch and/or impact resistant. The powder coating can be coloured and thus provide a coloured coating to the product. The powder coating may be transparent or translucent and may have the appearance of a varnish on the surface of the product.

(43) It will be understood that a very wide range of different composite products could be formed using methods as described herein. The application of the present invention is not restricted to the formation of, for example, panels.

(44) In a further example shown in FIGS. 5a to 5c, a profiled composite panel is formed.

(45) As shown in FIG. 5a, the substrate 144 is first crushed in a cold press 120 to form a profile on a surface of the substrate. The substrate in this example is open-celled ACELL (RTM) foam of Acell Limited. The foam block is placed in the press between two plates 122, 124 of which one has a surface profile to be moulded into the surface of the ACELL foam. As the plates are pressed together, the frangible foam is crushed so that the profile of the plate 122 is formed onto the surface.

(46) It will be appreciated that in other examples, two contoured plates could be used to form a block having more than one profiled surface.

(47) FIG. 5b shows the lay up for the pressing step. The shaped block of foam forms the substrate 144 which is placed at the base of the arrangement. The thickness of the foam is about 40 mm. A sheet of SMC having a thickness of about 3 mm is draped over the contoured surface 145 of the substrate 144.

(48) Onto the upper surface of the SMC sheet 140 is arranged a boundary wall 146 comprising four strips of wood arranged in a generally rectangular configuration to bound the area above the substrate at its perimeter. The wall 146 on the SMC sheet 140 forms a box into which the particulate surface material, in this example sand 130, is filled.

(49) Prior to filling into the box, the sand is heated to a temperature of about 130 degrees C. The sand is poured into the box and leveled. The thickness of the sand is about 10 mm.

(50) A press plate 148 is then used to press the sand 130 down onto the substrate 144. FIG. 5c shows the arrangement during the pressing step. It will be seen that at the substrate/SMC interface 147, the curable material of the SMC has moved into the surface of the substrate to key into the cellular structure to give a strong bond on curing. At the SMC/sand interface 148, some of the sand 130 has become embedded in the polymer skin which, on curing, provides a convincing simulated sandstone surface.

(51) Once the curing is complete or sufficiently complete, the composite product is removed from the press and the sand brushed from the surface to reveal the simulated stone surface on the polymer skin 149 on the surface of the substrate 144.

(52) It has been found that the actual thickness of the sand used is not critical in many applications. The SMC layer will only take up what it needs to form the sandstone surface, and the remainder of the sand forms a mould-like element to press the SMC into the substrate 144. It is has been found that in many arrangements, a good sandstone surface finish is obtained, even without any further surface treatment, although such finishing treatments could be used if desired.

(53) Variations may be made within the scope of the invention. For example, in some examples, the press arrangement may be provided in reverse formation, with the sand layer at the lower regions, and the substrate above, a pressing plate being provided at the top of the press. In such an arrangement, a lower mould portion comprising a number of regions could be provided. Surfacing material of different types could be provided in different regions of the mould. For example, the mould could form a brick pattern, with different coloured sand or other material being provided in different brick regions; the product formed using this filled mould could have the appearance of a brick wall including bricks of different colours. The surfacing material in different regions could differ as to one or more of material, particle size, particle shape, colour or other property. In other arrangements, the bricks might be provided to look substantially all the same, or different effects may be provided.

(54) The particulate or granular material may be applied to the arrangement for pressing as a loose-grained material, or as a block of material, the block being deformed or broken down during the pressing or moulding.

(55) Veneer

(56) FIG. 6 shows schematically a plan view of an aluminium mould 220. The mould comprises a surface contour suitable for moulding a door panel. The moulding surface is rectangular and includes an outer frame section 222, a rectangular inner panel section 224 and a bead 226 between the panel section 224 and the outer frame 222. The mould is heated to a temperature of approximately 140 degrees C.

(57) Wood veneer elements are placed in the mould 220 as shown in the sectional view in FIG. 7. In this case, a plurality of veneer elements are used. Frame element 232 is placed onto the outer frame section 222, panel element 234 on the panel section 224 and a bead element 236 in the bead 226 of the mould. Each of the veneer elements may comprise one or more components which may be joined prior to moulding or may be separate.

(58) A sheet of sheet moulding compound 240 is applied to the upper surface of the mould veneer. The sheet 240 is sized so as to extend across the whole area of the mould surface 220.

(59) Further elements for forming the laminate are shown in FIG. 8. It will be appreciated that in FIG. 8 and in other of the figures the shapes of the components are shown schematically. In particular, the relative thicknesses of the elements are not shown to scale. For example, the preferred thickness of veneers is about 3 mm.

(60) Onto the sheet 240 is placed a wooden frame 242 is positioned onto the sheet 240 (FIG. 8) and a block of foam substrate 244 is inserted into the frame 242.

(61) The substrate 244 may comprise a foam, for example as described in more detail below.

(62) Such foam used is advantageously: structural and has significant load bearing properties frangible and can be formed under pressure and has no memory and therefore substantially retains its pressed form open cell and therefore allows the migration of clues resins into the cells during door manufacture to create a truly monolithic composite structure.

(63) In an example of the foam used, the cell size ranges from 0.5 to 3 mm and the density is 80 to 800 kg/m3.

(64) The block of foam 244 is sized so as to be thicker than the frame so that the upper surface of the foam 244 extends above the frame 242 when the foam 244 is inserted in the aperture of the frame 242.

(65) Downward pressure of about 100 tonnes is applied to the components (as arranged in FIG. 8) using a pressure plate 250. The substrate 244 is pressed toward the lower moulding surface 220, crushing the foam and moulding the lower surface of the substrate to the shape of the mould surface 220. The SMC sheet 240 is also pressed between the veneer 232, 234, 236 and the substrate 244. Near the heated mould surface 220, the SMC begins to liquefy and flow into cells at the surface of the substrate 244 as well as into pores and other spaces at the surface of the veneers 232, 234, 236.

(66) Air and other gases trapped between the SMC 240 and the substrate 244 passes through the open cell structure of the foam. The components are held in the mould with the application of pressure for a sufficient time for the SMC to cure for form a skin bound to the moulded substrate 244 and the veneer 232, 234, 236.

(67) The resulting product is removed from the mould. The cycle time for moulding the product may be about 4 minutes.

(68) It is seen that in this example, an upper mould portion is not required. In this example, the components are pressed against a single heated platen.

(69) Referring now to FIG. 9, a method is described in which a moulded door having a veneer surface is formed in a single pressing step.

(70) A lower mould 220 is provided and placed on a heated platen 225 so that the mould reaches a temperature of about 140 degrees C. The lower moulding surface 221 of the lower mould 220 may be flat or may be contoured as here according to the surface shape of a paneled door.

(71) A layer of veneer 233 is placed onto the moulding surface 221. The veneer layer 233 may include more than one element, for example as shown in FIG. 7. The veneer elements comprise for example thin portions of oak wood.

(72) A lower sheet 240 of curable material is applied to the veneer. The size of the lower sheet 240 is approximately the same as that of the lower moulding surface 221.

(73) A foam block 244 comprising ACELL foam is applied to the upper surface of the lower sheet 240. A wooden frame 242 is placed around the lower foam block. Alternatively, the frame 242 could be applied first, and the block 244 inserted into the frame. A reinforcement sheet 246 comprising a metal grid is placed in the frame 242 onto the lower foam block 244. Onto the reinforcement sheet 246 and within the frame 242 is placed an upper foam block 248 also comprising ACELL foam. A layer of adhesive may be applied between the two blocks 244, 248 to aid bonding. Onto the upper foam block is placed the upper sheet 252 of curable material.

(74) Optionally, onto the upper sheet of curable material 252 is placed further veneer elements 254. In some arrangements, it will be desired for the veneer to be present on both surfaces of the panel. In other arrangements, veneer on one surface of the door only will be required. In the latter case, it will be appreciated that the veneer may be arranged at the lower or the upper region of the moulded components.

(75) An upper mould 256 is provided having an upper moulding surface 258 contoured according to the surface shape of a paneled door or flat as shown here. The upper mould 256 is heated to a temperature of about 140 degrees C.

(76) The upper mould 256 is lowered onto the other components and pressure of about 100 tonnes is applied to press the upper mould 256 towards the lower mould 220.

(77) The upper block 248 and the lower block 244 comprise frangible foam and the surfaces of the blocks facing the adjacent mould surfaces 220 and 258 are crushed and moulded to the surface shape of the paneled door.

(78) The curable material of the upper and lower sheets 240 and 252 flow into the adjacent foam blocks 244, 248 and also into the veneers 233, 254 to form a mechanical bond. Curing of the curable material takes place in the heated mould so that the upper and lower sheets 240 and 252 form skins bonded to the upper and lower blocks.

(79) Once cure is complete after a few minutes, the formed door is released from the mould.

(80) Thus it can be seen how a door can be made in a single pressing operation.

(81) In an alternative example, the lower block 244, the reinforcement 246 and the upper block 248 are provided as a single unit.

(82) In other arrangements, the mould may be coated with a powder coating which then forms a coating on the product. This feature may be present in relation to any of the aspects of the invention. As an example, a powder coating can be applied electrostatically to the mould surface. Where the mould surface is heated, the powder coating melts or softens almost as soon as it is applied to the surface. For example the powder may include a polyester. The SMC or other matrix material (with or without integral reinforcing material) is then applied over the melted or softened powder coating. The melted or softened powder coating is then sticky on the surface of the mould and is thought to reduce movement of the matrix material during the moulding operation, which can in some cases give improved surface finish. In this example, the coating remains on the surface of the product, and provides a surface which is scratch and/or impact resistant. The powder coating can be coloured and thus provide a coloured coating to the product. The powder coating may be transparent or translucent and may have the appearance of a varnish on the surface of the product.

(83) It will be understood that a very wide range of different composite products could be formed using methods as described herein. The application of the present invention is not restricted to the formation of, for example, doors.

(84) Simulated Surface Effect

(85) In a method described in UK Patent Application No. 0719343.6, the skins are bonded directly to a foam core during a moulding step. A layer of sheet-form SMC is provided on the mould surface, a foam core is placed on the layer of SMC, and pressure is applied to mould the components together. During the moulding step, the core and SMC layer are moulded to the desired shape, and the SMC material becomes bonded to the core. The content of that patent application is incorporated herein by reference.

(86) FIG. 10 shows schematically a plan view of an aluminium mould 320. The mould comprises a surface contour suitable for moulding a simulated stone panel. The moulding surface is rectangular and includes a pattern of projections 322 arranged to emulate the position of gaps between adjacent blocks of a stone wall.

(87) The mould is heated to a temperature of approximately 140 degrees C.

(88) Graphite powder is dusted over the surface of the mould to form a surface effect layer 330.

(89) As shown in FIG. 11, a sheet of sheet moulding compound 340 is applied to the upper surface of the mould over the surface effect layer 330. The sheet 340 is sized so as to extend across the whole area of the mould surface 320.

(90) It will be appreciated that in FIG. 11 and in other of the figures the shapes of the components are shown schematically. In particular, the relative thicknesses of the elements are not shown to scale. For example, the preferred thickness of the SMC is about 1 mm whereas the thickness of the substrate is about 5 cm.

(91) Onto the sheet 340 is placed a wooden frame 342 is positioned onto the sheet 340 (FIG. 11) and a block of foam substrate 344 is inserted into the frame 342.

(92) The substrate 344 may comprise a foam, for example as described in more detail below.

(93) Such foam used is advantageously: structural and has significant load bearing properties frangible and can be formed under pressure and has no memory and therefore substantially retains its pressed form open cell and therefore allows the migration of clues resins into the cells during door manufacture to create a truly monolithic composite structure.

(94) In an example of the foam used, the cell size ranges from 0.5 to 3 mm and the density is 80 to 800 kg/m3.

(95) The block of foam 344 is sized so as to be thicker than the frame so that the upper surface of the foam 344 extends above the frame 342 when the foam 344 is inserted in the aperture of the frame 342.

(96) Downward pressure of about 100 tonnes is applied to the components (as arranged in FIG. 12) using a pressure plate 350. The substrate 344 is pressed toward the lower moulding surface 320, crushing the foam and moulding the lower surface of the substrate to the shape of the mould surface 320. The SMC sheet 340 is also pressed between the mould surface and the substrate 344. Near the heated mould surface 320, the SMC begins to liquefy and flows into cells at the surface of the substrate 344 as well as around the graphite powder to encapsulate the graphite into its surface.

(97) Air and other gases trapped between the SMC 340 and the substrate 344 passes through the open cell structure of the foam. The components are held in the mould with the application of pressure for a sufficient time for the SMC to cure for form a skin bound to the moulded substrate 344.

(98) The resulting product is removed from the mould. The cycle time for moulding the product may be about 4 minutes.

(99) It is seen that in this example, an upper mould portion is not required. In this example, the components are pressed against a single heated platen.

(100) A moulded panel having a stone-effect surface may be formed in a single pressing step.

(101) A lower mould 320 is provided and placed on a heated platen 325 so that the mould reaches a temperature of about 140 degrees C. The lower moulding surface 321 of the lower mould 320 may be flat or may be contoured as here according to the surface shape of a stone wall.

(102) A layer of surface effect material 330, here graphite is placed onto the moulding surface 321.

(103) A sheet 340 of curable material is applied. The size of the lower sheet 340 is approximately the same as that of the lower moulding surface 321.

(104) A foam block 344 comprising ACELL foam is applied to the upper surface of the lower sheet 340. A wooden frame 342 is placed around the lower foam block. Alternatively, the frame 342 could be applied first, and the block 344 inserted into the frame. A reinforcement sheet 346 comprising a metal grid is placed in the frame 342 onto the lower foam block 344. Onto the reinforcement sheet 346 and within the frame 342 is placed an upper foam block 348 also comprising ACELL foam. A layer of adhesive may be applied between the two blocks 344, 348 to aid bonding. Onto the upper foam block is placed the upper sheet 352 of curable material.

(105) Optionally, onto the upper sheet of curable material 352 is placed further surface effect material, for example graphite 354. In some arrangements, it will be desired for the cool touch surface to be present on both surfaces of the panel. In other arrangements, a cool touch surface on one surface of the panel only will be required. In the latter case, it will be appreciated that the surface effect material may be arranged at the lower or the upper region of the moulded components. In other words, the order of laying down of the components shown in FIG. 12 may be reversed.

(106) An upper mould 356 is provided having an upper moulding surface 358 contoured according to the surface shape of a wall panel or flat as shown here. The upper mould 356 is heated to a temperature of about 140 degrees C.

(107) The upper mould 356 is lowered onto the other components and pressure of about 100 tonnes is applied to press the upper mould 356 towards the lower mould 320.

(108) The upper block 348 and the lower block 344 comprise frangible foam and the surfaces of the blocks facing the adjacent mould surfaces 320 and 358 are crushed and moulded to the surface shape of the wall panel.

(109) The curable material of the upper and lower sheets 340 and 352 flow into the adjacent foam blocks 344, 348 and also around the graphite particles to form a mechanical bond. Curing of the curable material takes place in the heated mould so that the upper and lower sheets 340 and 352 form skins bonded to the upper and lower blocks.

(110) Once cure is complete after a few minutes, the formed panel is released from the mould.

(111) Thus it can be seen how a panel can be made in a single pressing operation.

(112) In an alternative example, the lower block 344, the reinforcement 346 and the upper block 348 are provided as a single unit.

(113) In some arrangements, the mould may be coated with a powder coating which then forms a coating on the product. This feature may be present in relation to any of the aspects of the invention. As an example, a powder coating can be applied electrostatically to the mould surface. Where the mould surface is heated, the powder coating melts or softens almost as soon as it is applied to the surface. For example the powder may include a polyester. The SMC or other matrix material (with or without integral reinforcing material) is then applied over the melted or softened powder coating. The melted or softened powder coating is then sticky on the surface of the mould and is thought to reduce movement of the matrix material during the moulding operation, which can in some cases give improved surface finish. In this example, the coating remains on the surface of the product, and provides a surface which is scratch and/or impact resistant. The powder coating can be coloured and thus provide a coloured coating to the product. The powder coating may be transparent or translucent and may have the appearance of a varnish on the surface of the product.

(114) It will be understood that a very wide range of different composite products could be formed using methods as described herein. The application of the present invention is not restricted to the formation of, for example, panels.

(115) Example of Preparation of SMC

(116) The SMC comprises a curable matrix and reinforcement.

(117) To prepare the SMC, the matrix is prepared by mixing, for example a polyester resin with minerals and additives, for example including calcium carbonate and titanium dioxide together with appropriate pigments.

(118) For example, in the case where the SMC is used in the preparation of a simulated sandstone surface, pigments or other materials may be added to the composition to give it a beige colour when cured.

(119) The matrix in the form of the resin paste is then applied to 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 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 degrees C. The resulting SMC can be compression moulded with heat. The shelf life of the SMC before use is usually a few weeks.

(120) Foam

(121) In some examples of the invention, the substrate comprises a foam having frangible cell walls. Preferably this term includes a foam for which under compression the foam crumbles by brittle fracture of the cell walls e.g. involving a clean fracture of the cell walls. Such a foam can retain a clear and substantially dimensionally accurate imprint in the crushed zone of an object through which the compressive force is applied. In general, it is preferred that the yield strength of the foam, which in this case means the minimum force required to cause the fracture of the cell walls and for the foam to crumble, is in the range of about 100 to 140 KPa (15 to 20 lbs/sq.in) more preferably at least 200 KPa (30 lbs/sq.in), since this provides useful impact resistance. In general, for a given foam composition, the greater the density, the greater the yield strength.

(122) By using a substantially rigid plastics foam with frangible cell walls, mouldings with depressed zones of moulding detail can be readily formed by applying a layer to the foam core with sufficient pressure to cause the cell walls of the foam in the areas behind the depressed zones of the skin to be fractured whereby the foam is caused to conform to the contours of the skin in those zones by controlled localised crushing. Thus, air gaps between the skin and the substrate can be avoided and it is not necessary to pre-form the substrate in the form of complicated shapes. This is particularly advantageous since the presence of such air gaps in prior art products has in some cases contributed to their inability to resist changes in temperature.

(123) For such a method, it is advantageous to use an open cell foam having frangible walls as pressing into a conventional foamed core such as of polystyrene is in some cases not successfully achieved because the resilience of the foam may cause distortion of the skins when the pressure is released.

(124) In some examples of the invention, plastics foam are preferred which are substantially open-cell and rigid. However, the foam is advantageously selected to be of a high density relative to the foamed polystyrene conventionally used, e.g. a density of 75 kg/m.sup.3 or above, since this gives a better feel to the panel and makes it sound and handle more like a conventional wooden panel. However, foams having lower densities may also be selected. Where a higher density is desirable, the foam may contain a filler, more preferably a finely divided inert and preferably inorganic solid. The filler may be selected such that it contributes to the panels ability to resist changes in temperature. In a particularly preferred embodiment, the filler is capable of absorbing moisture, e.g. as water of crystallisation.

(125) While particular reference is made in the examples to open celled frangible foams, any suitable foam may be used. In some examples of the invention, foams which are substantially open cell are preferred; for example, a polyurethane foam, but in some examples the foam might not be open celled. Preferably in such example, the structure of the substrate is such that gases can be released from the mould. Where the foam is open celled, a foam that has an open-cell configuration at production is particularly suitable. A foam that also has frangible cell walls is particularly preferred where the panel or other product to be formed has depressed areas, such as to provide a moulding effect. However, as described herein, the moulding of the substrate can be provided by other methods, for example machining.

(126) Any foam can be used some aspects of the invention. In many examples, rigid foam materials are preferred. For example a rigid foam could be used to form a panel having a substantially flat (unmoulded) surface which may or may not include surface pattern as described herein.

(127) Alternatively, or in addition, the surface of the foam may be contoured. The contours could for example be formed on the surface of a foam block, for example by machining or any other suitable method. In such cases, the foam need not for example be a frangible or compressible foam.

(128) Where a foam having frangible cell walls is used, the cell wall will fracture as pressure is placed on the foam by the application of the depressed areas of the mould. This localised increase in pressure will increase the pressure inside the cell, which will cause the gases to travel through the foam, and the cell to collapse thereby accommodating the depressed area of the skin.

(129) One suitable foam is a rigid filled phenolic foam. One particularly suitable foam is that produced by effecting a curing reaction between:

(130) (a) a liquid phenolic resole having a reactivity number (as defined below) of at least 1 and

(131) (b) a strong acid hardener for the resole, in the presence of:

(132) (c) a finely divided inert and insoluble particulate solid which is present 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 whereby a foamed phenolic resin product is produced.

(133) By a phenolic resole is meant a solution in a suitable solvent of the acid-curable prepolymer composition obtained by condensing, usually in the presence of an alkaline catalyst such as sodium hydroxide, at least one phenolic compound with at least one aldehyde, in well-known manner. Examples of phenols that may be employed are phenol itself and substituted, usually alkyl substituted, derivatives thereof provided that the three positions on the phenolic benzene ring o- and p- 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 but the cured products will be less highly cross-linked. However, in general, the phenol will be comprised mainly or entirely of phenol itself, for economic reasons.

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

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

(136) The mixture may also contain a compound having two active H atoms (dihydric compound) that will react with the phenol/aldehyde 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 OH groups contains not only methylene and/or alkyl-substituted methylene groups but also one or more hetero atoms, especially oxygen atoms, e.g. 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 e.g. 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.

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

(138) 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 preferred to be 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 one is used.

(139) 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 10/x where x is the time in minutes required to harden the resole using 10% by weight of the resole of a 66-67% aqueous solution of p-toluene sulfonic acid at 60 degrees C. The test involves mixing about 5 ml 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 degrees 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 1 for useful foamed products to be produced and preferably the resole has a reactivity number of at least 5, most preferably at least 10.

(140) 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.

(141) 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.

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

(143) 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 5-20 poises. Below 5 Poises, the amount of solvent present tends to present difficulties during the curing reaction.

(144) The curing reaction is exothermic and will therefore of itself cause the temperature of the mixture containing resole and acid hardener to be raised. 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) must not exceed 85 degrees C.

(145) If the temperature of the mixture exceeds 85 degrees C. before addition of the hardener, it is 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 degrees C. after addition of the hardener.

(146) Increasing the temperature towards 85 degrees 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 degrees 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 degrees C. are preferably avoided and preferred temperatures for most applications are from ambient temperature to about 75 degrees C. The preferred temperature range appears to depend to some extent on the nature of the solid (c). For most solids it is from 25 to 65 degrees C. but for some solids, in particular wood flour and grain flour, the preferred range is 25 to 75 degrees C. The most preferred temperature range is 30 to 50 degrees C. Temperatures below ambient, e.g. down to 10 degrees C. can be used, if desired, but no advantage is gained thereby. In general, at temperatures up to 75 degrees C., increase in temperature leads to decrease in the density of the foam and vice versa.

(147) 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 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, we mean the amount of chosen hardener required to give substantially the same setting 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 25-75 degrees 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 degrees C. or resoles having a reactivity number below 10, it may be necessary to use more hardener.

(148) It may be necessary to make some adjustment of the hardener composition in accordance with the nature, especially shape and size, of the mould and this can be established by experiment.

(149) 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 setting 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.

(150) Another factor that controls the amount of hardener required can be the nature of the inert solid. 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.

(151) 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.

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

(153) It is believed that the finely divided particulate solid provides nuclei for the gas bubbles formed by the volatilisation of the small molecules, primarily CH.sub.20 and/or H.sub.2O, 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. The phenomenon may be similar to that of froth flotation employed in the concentration of low grade ores in metallurgy. In any event, the presence of the solid is essential to the formation of the product. 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.

(154) Any finely divided particulate solid that is insoluble in the reaction mixture is suitable, provided it is inert. The fillers may be organic or inorganic (including metallic), and crystalline or amorphous. Even fibrous solids have been found to be effective, although not preferred. Examples 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 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.

(155) 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.

(156) 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.

(157) 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 1 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.

(158) 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.

(159) 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.

(160) 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.

(161) 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.

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

(163) Thixotropic foam-forming mixtures can be obtained if a very finely divided solid such as Aerosil (finely divided silica) is included.

(164) If a finely divided metal powder is included, electrically conducting properties can be obtained. The metal powder is preferably used in amounts of from 50 to 250 parts per 100 parts by weight of resole.

(165) 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, when the mixture is like a dough or paste and cannot be poured, foamed products with valuable properties can be obtained.

(166) In general, it is preferred to use the fibrous solids only in conjunction with a non-fibrous solid since otherwise the foam texture tends to be poorer.

(167) 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(ethylene oxide) 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.

(168) 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.

(169) 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.

(170) 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.

(171) The foam-forming compositions may also contain dehydrators, if desired.

(172) A preferred method of forming the foam-forming composition comprises first mixing the resole and inert filler to obtain a substantially uniform dispersion of the filler in the resole, and thereafter adding the hardener. Uniform distribution of both the filler and the hardener throughout the composition is essential for the production of uniformly textured foam products and therefore thorough mixing is required.

(173) If it is desired that the composition is at elevated temperature prior to commencement of the exothermic reaction, this can be achieved by heating the resole or first mixing the resole and the solid and then heating the mixture. Preferably the solid is added to the resole just before the addition of the hardener. Alternatively, the mixture of resole, solid and hardener may be prepared and the whole mixture then heated, e.g. by short wave irradiation, preferably after it has been charged to a mould. A conventional radiant heat oven may also be used, if desired, but it is difficult to achieve uniform heating of the mixture by this means.

(174) Preferably, the foam has a density in the range 75 to 500 kg/m.sup.3, more preferably 100 to 400 kg/m.sup.3 and most preferably 100 to 250 kg/m.sup.3. Foam cell size is also important because up to a limit the larger the size of the cell for a given density, the thicker will be the walls and hence the greater the physical strength of the foam. However if the cell size is too large, the strength begins to suffer. Preferably, the cell size is in the range of 1 to 3 mm.

(175) It will be understood that the present invention has been described above purely by way of example, and modification of detail can be made within the scope of the invention.

(176) In particular, the examples above have been described in relation to the manufacture of panels. However, it should be appreciated that the invention has very wide application including other products. Indeed it is envisaged that an extremely wide range of products could be made in accordance with methods of the present invention. Many moulded products could be made using the methods of the present invention, even where those products may currently be manufactured using different materials (for example wood, stone, metal, porcelain) at present. For example, the techniques of the present invention could be used to form, for example mullioned windows, pillars, baluster, banister, or even statues or other ornamental articles. In addition to building products, it is envisaged that for example, the invention could find application to vehicle parts and fittings, casings for electrical equipment and many household items of which furniture, picture frames, chairs, tables, lamp bases, vases, bowls are only a few examples.

(177) While particular reference has been made to the simulation of stone surfaces, features of the invention may be used in the preparation of other surfaces, for example brick-effect surfaces or any other surface effect where a granular surface is desirable.

(178) FIGS. 4a and 4b shows an example where the techniques described above are used to form an three dimensional decorative article having a stone-effect surface.

(179) FIG. 4a shows the components for moulding the article in a single moulding step. A lower mould 120 for the article is heated and a granular layer of sharp sand 130 is dusted onto the mould. A coating may be applied to the mould to allow the sand to stick to the mould surface without slipping to the lowest point of the mould. For example, the coating may include an adhesive sprayed onto the mould surface.

(180) SMC sheet 140 is applied to the mould cavity and a plurality of blocks 150 of open cell foam are inserted into the mould. Adhesive may be applied to bond the blocks together. Alternatively, or in addition shaped blocks of foam may be used.

(181) A second layer of SMC 152 is applied over the blocks 150, and a further layer of granular material, for example sand 154 is applied to the SMC layer, and/or to the upper mould 156. Adhesive may be applied to the SMC layer 152 and/or the mould 156 to aid the adhesion of the sand where required.

(182) The mould pieces are then brought together under pressure to compress the components and to cure the SMC.

(183) The resulting article 160 is taken from the mould when the moulding process is complete. A sandblasting step removes some of the cured SMC material from the surface of the article 160, exposing the sand grains and providing a simulated stone surface on the article.

(184) In summary, aspects of the present invention relate to methods of manufacturing composite products having a surface effect. In some examples described, a composite product has a simulated surface, for example a stone-effect surface formed by pressing a particulate-form surface material and a sheet-form curable material onto a substrate having an open-celled structure. In other examples, a laminate product having a veneer is formed by pressing a veneer and a sheet-form material onto a substrate including a porous structure. The veneer may comprise a wood material. In other examples, a surface effect material is bonded to a skin by pressing a sheet-form curable material to a mould surface and the surface effect material. Where the surface effect material has a high thermal conductivity, the composite product formed can feel cool to the touch.

(185) Each feature disclosed in the description, and (where appropriate) the claims and drawings may be provided independently or in any appropriate combination.

(186) Thus it will be appreciated that the various methods described herein could be combined as appropriate to form a particular product. For example, a composite product might have a simulated stone surface in addition to a surface effect applied so that the material feels cool to the touch, and/or a patterned effect. Such effects may all be applied to the same or different surfaces of the product and to the same or different regions of the surface of the product.