WO1995013916A1

WO1995013916A1 - Panel

Info

Publication number: WO1995013916A1
Application number: PCT/GB1993/002362
Authority: WO
Inventors: Maurice Hinde
Original assignee: Minster Composite Industries Limited
Priority date: 1992-05-14
Filing date: 1993-11-16
Publication date: 1995-05-26
Also published as: GB2266858B; GB9210309D0; GB2266858A; AU5469894A

Abstract

A panel, suitably in the form of a door, comprises surface layers of fibre-reinforced plastics, especially resin (10, 11), and a core portion (12) which preferably comprises filler particles bonded by resin. Parts of the core portion may be of different thicknesses to provide a profiled panel surface. The core portion may have regions (14) in which the filler particles are of different size to those in other regions, corresponding to thickness variation in the panel. The panel suitably is made by compression moulding in which preferably the plastics material of the surface layers and the bonding agent of the core portion are compatible and thermosetting. There is also provided a mould for manufacture of the panel, comprising at least one position-adjustable mould element, typically in the form of at least one adjustable edge member, whereby the mould may be used to produce a variety of panel sizes and shapes.

Description

Title: Panel Description of Invention

This invention relates to a panel and to a method of manufacture thereof. The panel may be a door, e.g. an entrance door or internal door for a building, or could be for other purposes, e.g. a cladding panel.

Doors for buildings have long been made of wood and the appearance of a wooden door is generally regarded as being attractive for many applications. For many applications, however, whilst the appearance of a conventional wooden door may be desirable, properties of greater strength, fire resistance and so on may be required than is readily achievable with conventional wooden door constructions.

It is one object of the present invention to provide a panel to meet such requirements. Further objects and advantageous features of. and arising from, the invention are pointed out in more detail hereinafter.

According to one aspect of the present invention, we provide a panel comprising first and second surface layers of fibre reinforced plastics material, spaced from one another in the direction of the thickness of the panel by a core portion.

Preferably the core portion comprises particles of a filler material and a bonding agent for said particles so that the core is substantially rigid.

Different parts of the panel may be of different thickness from one another, the core portion of the panel being of a different thickness at said pans whilst the surface layers of the panel are of substantially constant thickness across their whole area.

The panel is preferably a door, and may have the -appearance of a wooden door having stiles, rails, mullions and panels.

The fibre reinforced plastics material of the surface layers may comprise a plastics resin material of thermosetting type, e.g. a polyester resin or possibly another type of resin, e.g. an epoxy resin, a phenolic, or a methylmethacrylate resin and the fibre reinforcement is preferably glass fibres which may be in the form of chopped strand mat, and/or continuous filament, and/or woven cloths and/or rovings of the fibre. The bonding agent of the core portion is preferably the same resin as that in the surface layers.

Preferably the surface layers have a pigment or pigments to present the colour of an appropriate type of wood, which pigment or pigments is incorporated in a coating of resin such as is generally known as a gel coat.

The surface layers may have, preferably in the gel coat, a surface finish which is textured, e.g. to simulate wood grain.

The core portion of the panel may incorporate regions in which the filler particles are of a different size from those in other regions of the core portion.

Preferably the core portion is arranged so that over substantially the entire area of the panel the core portion comprises a material including filler particles of one size or range of sizes, whilst where the panel is thicker, additional core portions of a further core material containing filler particles of a larger size or range of sizes are introduced. At said thicker parts of the panel, the additional core portions preferably lie between layers of the first core material.

The particles of the core portion may comprise grains of a recycled glass material which is known by the Trade Name PORAVER. Such grains are generally spherical in shape, are available in different sizes or ranges of sizes, and are lightweight and non-absorbent so that when bonded by a bonding agent they provide a low density rigid core material. They also impart to a panel using such a core material a high degree of resistance to fire. When grains of larger size are bonded together, a material of lower average density is obtained which may be used as additional core portions in the parts of the panel of greater thickness.

A panel in accordance with the invention can present the appearance, with a high degree of realism, of a wooden panel or door, and by virtue of its construction can be extremely strong as well as being intrinsically stable, resistant to atmospheric influences, fire resistant^', and relatively light in weight.

It is also possible to incorporate inserts for the attachment of hardware, e.g. hinges and locks, and to provide apertures for the reception of glazing panels and, for example, a letter box. For situations where a high security requirement exists, a layer of expanded metal or metal mesh could be incorporated, e.g. in the core portion. Tubes extending the entire height or width of the door for receiving security bolts could be incorporated.

According to another aspect of the invention, we provide a method of manufacturing a panel, comprising placing first and second surface layers, spaced from one another by a core portion, in a mould, said first and second surface layers each comprising reinforcing fibres and a settable resin; the mould comprising opposed mould elements having surfaces engaging said surface layers; applying . pressure to the material between the mould elements and causing or allowing the resin to set to provide a substantially rigid panel having surface layers which conform closely to the configuration of the surfaces of the mould elements.

The method may comprise applying to a first mould element a first surface layer which comprises a gel coat (which may incorporate pigment) and a settable resin containing reinforcing fibres. A core material may then be applied to the first surface layer. The second surface layer, preferably also comprising a settable resin and reinforcing fibres therein, may either be laid on the core material on the first mould element, after which a second mould element is applied to the second surface layer, or may be laid-up on a second mould element which is then brought onto the core material on the first mould element. A s,e\ coat for the second surface layer may be applied to the second mould element prior to application of the resin and fibres of the second surface layer thereto, or, if the resin and fibres of the second surface layer are laid on the core material on the first mould element, prior to the bringing of the second mould element onto the first mould element.

The core material may comprise particles of filler mixed with settable resin and may be applied by pouring the material onto the first surface layer on the lower mould element.

Preformed additional core portions comprising filler particles in a bonding agent may be applied where required in the core portion.

Preferably pressure is applied to the material between the mould elements by a vacuum method, by partial evacuation of the interior of the mould.

The method may comprise adjustably positioning mould edge members in the first mould element prior to the application of the first surface layer and core material thereto. The use of mould edge elements whose position is able to be adjusted enables pαne s of different sizes to be made using a single mould. One or more mould edge elements may be provided with formations for forming rebates or other special configurations at one or more edges of the panel.

According to another aspect of the invention, we provide a mould for manufacture of a panel having surface layers of fibre-reinforced plastics material, the mould comprising respective mould elements disposable in opposition to one another whereby surface layers of the panel can be caused to conform to the configuration of surfaces of the mould elements.

Preferably the mould includes at least one mould edge element, which preferably is adjustable in position, so that panels of different sizes may be manufactured and at least one edge portion of a panel can be provided with a required configuration.

The invention will now be described by way of example only with reference to the accompanying drawings, wherein:-

FIGURE 1 is a cut-away perspective view of part of a door in accordance with the invention;

FIGURE 2 is a horizontal section through a door in accordance with the invention;

FIGURE 3 is an enlargement of an edge portion of the door shown in Figure 2;

FIGURE 4 is a perspective view of a mould assembly used in manufacture of the door.

Referring firstly to Figure 1 of the drawings, this shows a corner portion of a door which is an example of a panel in accordance with the invention. This comprises a first surface layer 10, a second surface layer 11, and a core portion indicated generally at 12 spacing the surface layers 10, 11 from one another in the direction of the thickness of the door.

Each of the surface layers 10, 11 is of fibre reinforced plastics material, comprising reinforcing fibres preferably of glass set in a plastics resin material and having, on its visible surface, a gel coat of plastics resin material presenting the required visible appearance.

As illustrated, it will be seen that the surface finish of the first surface layer 10 provided by the gel coat of such layer is a simulation of a wood grain as indicated at 13. The gel coat also incorporates a desired pigment or pigments to present the colour of a selected variety of wood.

The door shown in Figure 1 has the appearance of a wooden door having stiles, rails, mullions and panels, and the surface layers 10, 11 have a surface shape which corresponds to the features of a wooden door so that the thickness of the door varies across its area.

The surface layers 10, 1 1 are of substantially constant thickness, the thickness of the core portion 12 varying across the area of the door in accordance with the surface features thereof.

The material of the core portion 12 comprises particles of a filler material and a bonding agent. The filler material is preferably recycled glass grains of the type under the Trade Name PORAVER and the bonding agent is preferably a plastics resin of the same type as is used in the surface layers 10, 11. In places where the door is thickest, the core portion incorporates central regions 14 where grains of filler material of a larger size or range of sizes are used than are used in the remainder of the material of the rest of the core portion.

Since the grains are preferably substantially spherical, the use of larger size grains has the effect that the regions 14 are of lesser density than the rest of the core portion. By way of example, the core material 12 may comprise grains in the size range .5mm to 4mm, while the grains in the regions 14 may be in the size range 2mm to 8mm. Different sized grains within such ranges or other desired ranges may be incorporated in the core portion.

At the bottom of the door, the surface layers 10, 11 extend around the edge as indicated at 10a, 11a to meet each other so that the core portion is not exposed at such lower edge. At the vertically extending edge of the door, the surface layers similarly extend to meet each other and conceal the core portion therebetween but at such edge a rebate 15 is provided as described hereafter.

Figure 2 is a horizontal section through an entire door of a type whose corner is shown in Figure 1. The cross section is that of a wooden door having stiles 20, 21 and a mullion 22 and panels 23, 24 therebetween. The stile 20 and adjacent part of panel 24 are shown enlarged in Figure 3. These figures illustrate that the core material extends throughout the door but in the thickest part thereof provided by the stiles, mullion and panels therebetween there are provided regions of a further core material in which the larger grains of filler material are incorporated.

Manufacture of a door as set forth above will now be described with reference to Figure 4 of the drawings, which shows a portion of a mould for use in such manufacture.

The mould assembly as shown in Figure 4 comprises a lower support member 30 and an upper member 31 which co-operates therewith. The lower member 30 is, as a whole, generally of rectangular shape in plan view having a central recess 32 bounded by a peripheral portion 33 which includes a trough 34 extending around the entire periphery of the member 30. Outwardly of the trough 34 there is a shallower trough 35 in which lies a compressible, e.g. elastomeric sealing element 36. A pipe 37 communicates with the trough 34 and is arranged for connection, by way of a control valve 38, to a vacuum pumping system. A gauge 39 measures the extent to which the pressure in trough 34 is reduced below atmospheric pressure when in use as described hereafter.

The upper member 31 of the mould comprises a central portion 40 facing the recess 32 in the lower mould member 30, and a peripheral portion 41 having a peripheral flange 42, arranged to co-operate with the peripheral portion 33 of the lower mould member so as to engage the sealing element 36 thereof.

Within the recess 32 of the lower mould member 30 there is provided a lower mould element 43 which is provided with formations as shown at 44 to form the required surface configuration on a door which is to be manufactured. An upper mould element 45 similarly having formations 46 is secured to the portion 40 of the upper mould member 31, facing the lower mould element 43. For providing the required shape along the edges of a door being manufactured, mould edge members 47, 48 are provided, having formations 49, 50 respectively for forming rebates in the door edges. The mould edge members 47, 48 may be adjustable in position, the member 48 being adjustable in its position e.g. by screw devices as shown at 51.

Manufacture of a door according to the invention is commenced with the upper mould member 31 removed from the lower mould member, so that the mould element 43 and the mould edge elements 47, 48 are accessible. A suitable release agent of a type generally known for use in manufacture of components of fibre reinforced plastics material is applied to the surfaces of the mould elements, followed by a surface layer of gel coat and resin in flowable form containing reinforcement fibres. The reinforcement fibres are preferably glass, in the form of chopped strand mat and/or other form, e.g. rovings or woven cloth, and the resin is conveniently a polyester resin which has been mixed with a suitable catalyst which will ultimately cause the resin to set. The surface layer may be established on the mould element 43 by application of the gel coat thereto followed by application of the reinforcing fibres and their resin by a "laying up" technique as is generally known for manufacture of components of fibre reinforced plastics material. The gel coat may contain a pigment or pigments to cause it to adopt the colour of a particular type of wood which is to be simulated. After such application of the surface layer, the core material is introduced. Preferably the core material comprises granules of the low density, fire resistant filler material as aforesaid and a bonding agent which preferably is a resin-catalyst mixture of the same type used in the first surface layer. Such a material may be mixed and poured onto the surface layer on the lower mould element 43, being suitably spread to the required thickness at different parts of the mould.

In the thicker parts of the door to be manufactured, core elements comprising filler granules of greater size than those in the core material which has been poured into the mould, and which had been preformed, e.g. by setting in open moulds or troughs, may be laid on the core material which has been poured into position, after which further core material would be poured thereon so that the preformed core elements are covered.

Thereafter the further surface layer, comprising resin and reinforcing fibres, is introduced. This further surface layer may be provided by applying it to the core material and first surface layer which is already present. Alternatively, the further surface layer may be applied to the upper mould element 45 in the same way that the first surface layer was applied to the lower mould element 43. A gel coat for the further surface layer is applied to the upper mould element, prior to the application of resin and fibres thereto if the further surface layer is to be provided in this way.

The upper mould member 31 is then positioned on the lower mould member 30 as shown. The sealing element 36 is compressed between the mould members to establish a substantially airtight seal, and the control valve 38 is operated so that air is evacuated from the space between the mould members by way of the pipe 37 and trough 34. This causes the material between the mould elements 43, 45 to be compressed so that the surface layers therebetween conform closely to the configuration of the mould elements including the formations 44, 46 thereof. This condition is maintained until the resin in the surface layers and core portion therebetween has set, after which the mould members can be separated and the finished door extracted from the mould.

A door thus manufactured has many advantages. One such advantage is that it is extremely strong but of relatively light weight, by virtue of its construction of fibre reinforced plastic surface layers and the core comprising resin-bonded granules or particles of low density filler material therebetween. By use of suitable filler material in the core portion, a high level of fire resistance may be attained. By suitable colouring and texturing of the gel coat providing the visible surface of each surface layer, an extremely realistic simulation of a wooden door may be provided.

Although polyester resin is above referred to as comprising the resin in the surface layers and that which is the bonding agent for the particles of filler material in the core of the door, it will be appreciated that other resin materials such as are generally known for use in the manufacture of fibre-reinforced plastics articles may be used in the present invention. Similarly filler materials other than the glass granules above referred to may be used, for example clay prill or a foam material, or virtually any inert low density filler which may establish voids in the core portion.

The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims

1. A panel comprising first and second layers of fibre-reinforced plastics material, spaced from one another in the direction of the thickness of the panel by a core portion.

2. A panel according to Claim 1 wherein said core portion comprises particles of a filler material and a bonding agent for said particles.

3. A panel according to Claim 1 or Claim 2 wherein different parts of the panel are of different thicknesses from one another, the core portion of the panel being of a different thickness at said parts whilst the surface layers of the panel are of substantially constant thickness across their whole area.

4. A panel according to any one of the preceding claims which is a door.

5. A panel according to Claim 4 having the appearance of a wooden door including portions simulating stiles, rails and mullions.

6. A panel according to any one of the preceding claims wherein said material of the surface layers comprises a thermosetting plastics resin.

7. A panel according to Claim 6 wherein said bonding agent of the core is the same resin as that in said surface layers.

8. A panel according to any one of the preceding claims wherein said surface layers include a resin coating having a pigment.

9. A panel according to any one of the preceding claims wherein said surface layers have a textured surface finish.

10. A panel according to any one of the preceding claims wherein said core portion incorporates regions in which the filler particles are of a different size from those in other regions of the core portion.

11. A panel according to Claim 10 wherein said core portion comprises a material including filler particles of one size or range of sizes over substantially the entire area of the panel, and where the panel is thicker additional core portions of a further core material containing filler particles of a larger size or range of sizes are present.

12. A panel according to Claim 11 wherein, at said thicker parts of the panel, the additional core portions lie between layers of the first core material.

13. A panel according to any one of the preceding claims wherein said particles of the core portion include grains of a lightweight glass material.

14. A panel according to any one of the preceding claims incorporating inserts for the attachment of hardware and/or to provide apertures for the reception of other components.

15. A method of manufacturing a panel, comprising placing first and second surface layers, spaced from one another by a core portion, in a mould, said first and second surface layers each comprising reinforcing fibres and a settable resin; the mould comprising opposed mould elements having surfaces engaging said surface layers; applying pressure to the material between the mould elements, and causing or allowing the resin to set to provide a substantially rigid panel having surface layers conforming closely to the configuration of the surfaces of the mould elements.

16. A method according to Claim 15 comprising applying to a first mould element a first surface layer comprising a gel coat and a settable resin containing reinforcing fibres; applying a core material to the first surface layer, and applying a second surface layer either on the core material or on a second mould element which is then brought onto the core material on the first mould element.

17. A method according to Claim 16 wherein a gel coat for the second surface layer is applied to the second mould element.

18. A method according to Claim 16 or Claim 17 comprising pouring the core material, comprising particles of filler mixed with a settable resin, onto the first surface layer on the lower mould element.

19. A method according to Claim 18 comprising applying preformed additional core portions where required in said core material.

20. A method according to any one of Claims 15 to 19 wherein pressure is applied to the material between the mould elements by partial evacuation of the interior of the mould.

21. A method according to any one of Claims 15 to 20 comprising adjustably positioning mould edge members in the first mould element prior to the application of the first surface layer and core material thereto.

22. A method according to Claim 20 wherein one or more of said mould edge elements are provided with formations for forming rebates or other configurations at one ore more edges of the panel.

23. A mould for use in manufacture of a panel by the method according to Claim 21 or Claim 22, comprising respective mould elements disposable in opposition to one another whereby surface layers of the panel can be caused to conform to the configuration of surfaces of the mould elements.

24. A mould according to Claim 23 including at least one mould element adjustable in position.

25. A panel substantially as hereinbefore described with reference to the accompanying drawings.

26. A method of manufacturing a panel substantially as hereinbefore described with reference to the accompanying drawings.

27. A mould substantially as hereinbefore described with reference to the accompanying drawings.

28. Any novel feature or novel combination of features described herein and/or in the accompanying drawings.

29. A panel according to any of Claims 1 to 14 wherein said core portion comprises filler particles of inert mineral material bound by a bonding agent which is compatible with the fibre-reinforced plastics material of the first and second layers.

30. A panel according to any of Claims 1 to 14 or 29 wherein said core portion comprises an amalgam of filler particles.

31 . A method according to any of Claims 15 to 22 wherein the core portion is semi-fluid at the commencement of moulding.