GB2344347A

GB2344347A - Decorative plastics articles

Info

Publication number: GB2344347A
Application number: GB9826558A
Authority: GB
Inventors: Edwin A Jewkes
Original assignee: SEAMLESS HOLDINGS Ltd
Current assignee: SEAMLESS HOLDINGS Ltd
Priority date: 1998-12-04
Filing date: 1998-12-04
Publication date: 2000-06-07
Also published as: GB9826558D0

Abstract

Decorative plastics articles simulating the appearance of terrazzo, granite or like stone material are formed by distributing 2-dimensional non-metallic, flexible flake material throughout a base polymer material. Articles can be cut with no loss of decorative effect at the cut edge. Articles with sharp bends can also be formed with a smooth finish without loss of decorative effect.

Description

DECORATIVE PLASTICS ARTICLES This invention concerns improvements in or relating to decorative plastics articles. The invention has particular, but not exclusive, application to decorative plastics articles imitating the appearance of terrazzo, granite or like stone material.

It is already known to produce decorative plastics articles imitating the appearance of terrazzo or granite by adding particulate material to a curable polymer material such as an epoxy resin. The particulate material is typically in the form of particles of random size and shape coloured to produce the desired decorative effect.

A disadvantage of such particulate material is that the polymer base material has to be relatively viscous to keep the particles in suspension.

As a result, thixotropic agents such as fumed silica are often required to increase the viscosity of the polymer base material making it more difficult to form into the required shape by moulding or casting.

A further disadvantage of such particulate materials is that the 3-dimensional shape of the particles can result in the finished article having a rough surface. In addition, the 3-dimensional shape of the particles cannot adapt to sharp changes in profile of the article such as tight bends. As a result, the shape of article which can be formed with a realistic decorative effect is restricted.

Yet another disadvantage of such particulate material is that the particles can be coloured on the outer surface only and with a limited colour range.

As a result, if it is necessary to cut the finished article, the particles are cut exposing uncoloured areas and altering the decorative effect.

The foregoing disadvantages have restricted the decorative plastics articles which can be produced with an imitation terrazzo or granite effect.

It is an object of the present invention to provide decorative plastics articles in which the foregoing disadvantages are mitigated.

It is a preferred object of the present invention to provide decorative plastics articles with a terrazzo, granite or similar stone material effect which can be formed into a range of shapes more easily.

It is a further preferred object of the present invention to provide decorative plastics articles with a terrazzo, granite or similar stone material effect having a smooth surface.

It is yet another preferred object of the present invention to provide decorative plastics articles with a terrazzo, granite or similar stone material effect which can be cut without loss of the decorative effect at the cut surface.

According to one aspect of the present invention we provide a decorative plastics article having a decorative effect by the presence of non-metallic flake material in a polymer base material.

Preferably, the flake material has a 2-dimensional shape with sufficient inherent flexibility to conform to changes in profile of the article. In this way, a smooth surface finish can be obtained without loss of decorative effect even when forming tight bends.

Advantageously, the flake material can have a wide range of colours with the colour being the same all the way through. As a result, no significant loss of decorative effect occurs when the article is cut.

Preferred flake materials are polymers obtained from emulsions of homopolymers such a polyvinyl acetate (PVAc) or copolymers such as acrylic/styrene copolymer to which pigments can be added to produce flake material having any desired colour different from the colour of the base polymer material.

Preferably, the flake material consists of flakes dispersed throughout the base polymer material. The flakes may be of one colour or a mixture of colours. The flakes may be of similar size and shape. Alternatively, the flakes may be of different size and shape. The thickness of the flakes is preferably in the range from 70 microns to 200 microns and the size of the flakes can vary from a few microns to 10mm.

Advantageously, the amount of flake material added can be varied according to the decorative effect to be created. For example, a terrazzo effect may be produced with less than 20% parts by weight of flake material and more preferably with 5-10% parts by weight of flake material while a granite effect may be obtained with 30-60% parts by weight of flake material and more preferably with 40-50% parts by weight of flake material.

As will be appreciated the flake material is considerably lighter than the particulate material used previously. As a result, the base polymer material can be less viscous allowing the flake material to disperse easily throughout the base polymer material and facilitating manufacture by moulding, casting or other suitable technique. Preferred base polymer materials are epoxy resins but other resin materials may be used such as methacrylates, polyurethanes, melamines, acrylics, phenolics, polyesters and the like. Advantageously, the base polymer material is formulated to provide the appropriate characteristics for the intended use of the finished article. For example, base polymer materials which are resistant to attack from solvents and are capable of withstanding extremes of temperature with good abrasion resistance may be used to produce sinks or worktops for domestic and/or commercial use.

Acid cured epoxy resins having these characteristics and being in addition non-toxic and sterile are particularly suitable for producing sinks and worktops.

According to another aspect of the present invention we provide a method of making a decorative plastics article having a decorative effect comprising the steps of placing a curable base polymer material containing non-metallic flake material in a mould and curing the base polymer material to form an article having the flake material dispersed throughout the base polymer material to create a decorative effect in the article.

Preferably, the flake material is PVAc flake and the base polymer material is an epoxy resin curable at elevated temperatures but other materials may be used. Where the base polymer material is an epoxy resin, curing with an acid curing agent, for example an acid anhydride, provides resistance to elevated temperatures especially suitable for sinks and worktops which may have hot pans or the like placed on them.

An example illustrating the invention will now be described in more detail.

An aqueous PVAc emulsion was prepared having the composition shown in table 1 below and a thin coating layer of the emulsion applied to an endless moving belt of low friction material such as polytetrafluoroethylene (PTFE) using an adjustable doctor blade to control the thickness of the coating layer. The coating layer was then dried by heating with microwaves or any other suitable heat source such as gas burners and stripped from the belt by a jet of air directed under the dry coating layer. The dry PVAc removed from the belt was collected and broken up in a mill to produce PVAc flakes approximately 70 microns to 200 microns thick and varying in size from a few microns to 10 mm.

The PVAc flakes can be separated into different sizes using appropriate sized sieves or screens. The resulting PVAc flakes were white and had a 2-dimensional shape with a degree of inherent flexibility enabling the flakes to bend as described later. Coloured flakes may be produced with the addition of pigment tinters to the formulation.

Table 1 Material % parts by weight Water 6.50 PVAc 27.69 Kalipol 0.10 Dispex 0.14 Igepal 0.25 White Spirits 1.36 Caster Oil 0.76 Talc 5. 43 Barium Sulphate 27.15 Calcium Carbonate 27.15 Titanium Dioxide 3.47 Kalipol is a polyphosphate solution available from Albright & Wilson Ltd.

Dispex is a polymeric dispersing agent available from Allied Colloids Ltd.

Igepal is a surfactant available from Rhone-Poulenc Surf.

Using the PVAc flake material described above a curable epoxy resin composition was prepared having the composition shown in Table 2 below and poured into a mould to form an annular test disc with an edge lip of reduced thickness. The mould was then placed in an oven at atmospheric pressure and heated to 110 C for 1 hour and 154 C for a further 2 hours to set the resin composition. As the resin composition was setting, the mould was removed periodically from the oven and additional resin composition added to top-up the mould to accommodate shrinkage of the resin composition. On removal from the mould the disc was found to have a smooth surface with a decorative effect imitating the appearance of granite created by the distribution of the flakes in the epoxy resin and by the colour contrast between the flakes and the epoxy resin. The smooth surface is believed to be the result of the inherent flexibility of the 2-dimensional flakes enabling the flakes to bend and conform to the profile of the disc to maintain the smooth surface even where sharp changes in shape occur at the edge of the disc. On cutting the disc, the flake material was found to be distributed throughout the thickness of the disc reproducing the granite effect at the cut edge even where the flakes were cut due to the flakes being coloured throughout.

Table 2 Material % parts by weight Epoxy Resin (acid cure) 50-60 PVAc 40-50 The advantages of using non-metallic flake material to create a decorative effect will be apparent from the example above-described. In particular, articles of complex shape such as sinks can be produced having a smooth surface due to the flakes bending to conform to the profile of the article.

In addition, articles which may have to be cut such as worktops can be produced without loss of decorative effect at the cut edge due to the flakes being coloured throughout.

Furthermore, articles can be produced using any suitable moulding technique such as injection moulding.

It will be understood that different decorative effects may be produced by altering the amount of flake material incorporated in the polymer base material.

It will also be appreciated that the flakes may be of similar size and shape or a range of different sizes and shapes may be used depending on the decorative effect to be created.

Additionally or alternatively, the colour of the flakes and/or the polymer base material can be chosen to produce any desired decorative effect.

The flakes may be of one colour or combinations of different colours may be used.

It will further be understood that various modifications and changes can be made without departing from the inventive concept as described herein and all such modifications and changes are deemed within the scope of the invention.

Claims

CLAIMS 1. A decorative plastics article having a decorative effect by the presence of non-metallic flake material in a polymer base material.
2. An article according to Claim I wherein, the flake material has a 2-dimensional shape.
3. An article according to Claim 1 or Claim 2 wherein, the flake material has sufficient inherent flexibility to conform to changes in profile of the article.
4. An article according to any one of the preceding Claims wherein, the flake material is coloured and the colour extends all the way through the flake material.
5. An article according to any one of the preceding Claims wherein, the flake material is dispersed throughout the base polymer material.
6. An article according to any one of the preceding Claims wherein, the flake material consists of flakes of similar size and shape.-
7. An article according to any one of Claims 1 to 5 wherein, the flake material consists of flakes of different size and shape.
8. An article according to any one of the preceding Claims wherein, the flake material has a thickness in the range from 70 microns to 200 microns.
9. An article according to any one of the preceding Claims wherein, the flake material has a size up to 10mm.
10. An article according to any one of the preceding Claims wherein, the flake material is of one colour.
11. An article according to any one of Claims 1 to 9 wherein, the flake material is of different colours.
12. An article according to any one of the preceding Claims wherein, the flake material is a polymer.
13. An article according to Claim 12 wherein, the polymer is a homopolymer.
14. An article according to Claim 13 wherein, the homopolymer is polyvinyl acetate (PVAc).
15. An article according to Claim 12 wherein, the polymer is a copolymer.
16. An article according to Claim 15 wherein, the copolymer is acrylic/styrene copolymer.
17. An article according to any one of the preceding Claims wherein, the base polymer material is a resin.
18. An article according to any one of the preceding Claims wherein, the base polymer material is selected from the group comprising epoxides, methacrylates, polyurethanes, melamines, acrylics, phenolics and polyesters.
19. An article according to any one of the preceding Claims wherein, the decorative effect imitates granite.
20. An article according to any one of Claims 1 to 18 wherein, the decorative effect imitates terrazzo.
21. An article according to any one of the preceding Claims comprising a sink.
22. An article according to any one of Claims 1 to 20 comprising a worktop.
23. A decorative plastics article substantially as hereinbefore described.
24. A method of making a decorative plastics article having a decorative effect comprising the steps of placing a curable base polymer material containing non-metallic flake material in a mould and curing the base polymer material to form an article having the flake material dispersed throughout the base polymer material to create a decorative effect in the article.
25. A method according to Claim 24 wherein, a terrazzo effect is produced with 5-10% parts by weight of flake material.
26. A method according to Claim 24 wherein, a granite effect is produced with 40-50% parts by weight of flake material.
27. A method according to any one of Claims 24 to 26 wherein, the base polymer material is a resin selected from the group comprising epoxides, methacrylates, polyurethanes, melamines, acrylics, phenolics and polyesters.
28. A method according to any one of Claims 24 to 27 wherein, the flake material is PVAc flake.
29. A method according to any one of Claims 24 to 28 wherein, the flake material has a thickness in the range from 70 microns to 200 microns.
30. A method according to any one of Claims 24 to 29 wherein, the flake material has a size up to 10mm.
31. A method according to any one of Claims 24 to 30 wherein, the base polymer material is curable at elevated temperatures.
32. A method according to any one of Claims 24 to 31 wherein, the base polymer material is curable at atmospheric pressure.
33. A method of making a decorative plastics article substantially as hereinbefore described.
34. A decorative plastics article produced by the method according to any one of Claims 24 to 33.
35. A mouldable composition for a decorative plastics article made by the method according to any one of Claims 24 to 33 comprising a base polymer material and a non-metallic flake material dispersed throughout the base polymer material.
36. A mouldable composition according to Claim 35 comprising from 40% to 95% parts by weight of base polymer material and from 60% to 5% parts by weight of flake material.
37. A mouldable composition according to Claim 36 wherein the flake material has a 2-dimensional shape.