GB2080151A - A surface-covering material and process for the production thereof - Google Patents

Abstract

The surface-covering material simulates an external surface showing geometrically shaped elements (1) of inorganic material, e.g. stone, brick, or other ceramic, joined by a mortar or other matrix material (2) comprising a binder and a particulate material, which surface-covering material comprises a relief patterned plastics material having a printed colour pattern and displaying first areas including elements (2) positioned at first level, and displaying interjacent second areas at a second level adjacent the first level, the second areas being shaped and positioned to resemble material (2). The second areas form a relief adjacent the first areas, the first areas being constituted by colour patterned visible surfaces of a plastics material and the second areas being constituted by a particulate material, e.g. sand, adhered to the surface of a plastics material by means of an adhesive and substantially covering the adhesive. <IMAGE>

Description

SPECIFICATION A surface-covering material and process for the production thereof The present invention relates to a surfacecovering material simulating an external surface showing geometrically shaped elements (A) of inorganic material joined by a mortar or other matrix material (B) comprising a binder and particulate material and to a process for its production.

The wall surfaces of buildings, both indoors and on the outside, are often made from refractory materials. These comprise natural stone, such as granite or marble, of irregular shape or in geometrical forms, or artificial materials usually in geometrical shapes, e.g.

artificial stone, such as various chalk products or made from clay as in the case of bricks or of ceramic composition, such as tiles, clinkers or other materials in tile shape. The wall surface is built up from pieces of the above mentioned materials separated by mortar joints, which after setting generally show a fine surface granulation, dark granules and usually a colour different from the overall appearance. In most cases the mortar comprises sand and finely granulated binder, usually on a basis of chalk and sometimes with the addition of colouring matter. In the surface of the joint the granules of sand are clearly visible against the flat surface of the binder.Whereas the individual elements making up these composites may vary widely with regard to character, colourings and nuances, there is usually a contrast between the joints and the said elements, partly because of the surface of these elements being relatively planar or, at least, having flat areas, perhaps in addition thereto a different light reflection and they making a "hard" or "solid" impression on the observer. The rhythmical construction of the surface which is achieved by use of these materials and which relies on the contrast between the character of the elements and the material forming the joints is deemed attractive from an aesthetic point of view.By the same token many people appreciate the traditional character of the material and the impression of stability and durability associated with them: for these reasons there is a good market for these materials.

From a practical economic point of view the materials have considerable shortcomings.

They require considerable work and use a great deal of material for their production and application where they must be put in place one by one and joined by the mortar. Their heaviness increases cost as well as the stresses on the bearing construction. Some of the materials, e.g. brick or natural stone, are quite thick which at least when used indoors decreases the internal volume of the building.

All this put together has led to the desire to retain the aesthetic advantages of materials of this type and to eliminate their disadvantages.

Thus, there has been a need for an aestheti cally equivalent material, though in the form of relatively thin sheets or sheetings, easy to handle, not using much space and of relatively low price.

Such a material is found in the embossed and colour patterned synthetic materials which generally are used for the covering of floors and wall surfaces. Generally, products of this type comprise a PVC-foam layer, normally backed by a substrate such as felt. By control of the foam cell size in different parts of the product it is possible to create a relief or embossed pattern which completes, or is integrated with, a printed colour pattern. Its surface may be protected by a transparent PVC-layer. Although products of this kind are especially suitable for simulating many kinds of surfaces, really good, naturally looking reproductions of the mentioned surfaces consisting of stone or the like and of joints have been absent from the market.

Quite a number of the traditional materials, e.g. brick or polished stone, clinkers and ceramic tiles, are eminently suitable for imitation by synthetic plastics materials as mentioned above, as their surface can be given the required texture or grain appearance and the production potential of delicately shaded colour patterns is excellent. Even coarser stone surfaces can be imitated with good result. But when it comes to the surface texture of the joints between stone surfaces plastics material are not very suitable as it is not possible to imitate the uneven, mat, finely structured surface of a mortar joint.One of the weaknesses shown by material of this type and produced according to known methods consists in the unnatural impression made by the joints which look rather as if they were just "painted", spoiling the total impression in spite of the stone surfaces in between being rather realistic.

An object of the present invention is the provision of a surface-covering material simulating an external surface which is aesthetically pleasing and is simple to produce and which represents an improvement over prior proposals.

According to a first aspect of the present invention there is provided a surface-covering material simulating an external surface showing geometrically shaped elements (A) of inorganic material joined by a mortar or other matrix material (B) comprising a binder and a particulate material, the surface-covering material comprising a relief patterned plastics material having a printed colour pattern and displaying areas (C), the areas (C) including the said shaped elements (A) positioned at a first level, and displaying interjacent areas (D) at a second level adjacent the first level, the areas (D) being shaped and positioned to resemble the said mortar or other matrix material (B), and the areas (D) forming a relief adjacent the areas (C), wherein the areas (C) are constituted by colour patterned visible surfaces of a plastics material and the areas (D) constitute a particulate material adhered to the surface of a plastics material by means of an adhesive and substantially covering the adhesive. Preferably the elements (A) are bounded by a mortar or the matrix material (B). The elements (A) may be designed to stimulate natural stones, bricks or other ceramic products. The particulate material may comprise sand. The areas (D) may be depressed relative to the areas (C). In one expedient form of surface-covering material plastics material in the areas (D) is partly visible between and/or through the particles of the said particulate material, and the plastics material in the areas (D) is coloured so as to resemble the colour of the binder of the mortar or other matrix materials to be simulated.The solid particulate material may comprise particles of coloured thermoplastic material.

According to a second aspect of the present invention there is provided a method for producing a surface-covering material as defined by the first aspect of the invention, the method comprising coating a substrate with a foamable plastics composition displaying areas of dissimilar foamability corresponding to the said areas (C) and (D) respectively, thereby providing for the formation of the said first and second levels by foaming the plastics material and colour patterning of the said areas (C) and heating to cause foaming and formation of the end product, wherein an adhesive is printed on the plastics material in the pattern of the areas (D) in register with the decorative pattern of the areas (C), the said particulate material is applied to the surface of the plastics material while the adhesive is still in a sticky state, the said particulate material not attached to the adhesive is removed and the adhesive is solidified to retain the particulate material securely. The foamable plastics composition used for coating the said substrate is preferably a PVC-plastisol and preferably the said adhesive is a PVC-plastisol. The said adhesive may be a PVC-plastisol which is solidified by gelation during the said heating of the material. The particulate material may comprise thermoplastic particles, the thermoplast chosen having a melting range suitable for sintering to cause melting of the particles to coalesce without losing the particulate structure but sufficiently to form a textured yet dense surface; such particulate material may have particles ranging in size from 0.05-1.00 mm.In one especially advantageous form of method the said foamable plastics composition is applied as a plastics layer of uniform thickness to the said substrate, and is printed with said colour pattern by means of ink including inhibitor or accelerator for a blowing agent which is present so as to form both said first and second levels. With regard to the latter the required structure or texture of at least the surfaces of areas (C) may be obtained by differentially controlled foaming of the plastics layer. If desired, a layer of foamable plastics comOposition in the form of a plastisol is screen printed in regions defining areas (C) and a layer corresponding to areas (D) is applied as a second plastisol having a foamability different from that of the first plastisol.The first plastisol layer may be provided with a colour pattern by means of ink comprising an inhibitor or accelerator for a blowing agent which is present so as to produce surfaces of areas (C) having a fine structure or texture during foaming of the said layer. The colour pattern may be gravure printed without register with the pattern formed by partitioning the surface of the surface-covering material into areas (C) and (D).

By way of example preferred forms of the invention will now be described with reference to the accompanying diagrammatic drawings, wherein: Figure 1 is a front view of a surfacecovering material illustrative of the invention; Figures 2-4 represent cross-sections of elements produced at various production stages, Figure 5 represents a cross-section of the final product having a front view as depicted in Fig. 1.

In Fig. 1, a part of the said material simulating a brick wall is shown. The surface comprises a number of rectangular areas (1) which are disposed in a regular pattern and which below are called "stone surfaces", separated by relatively narrow corridors with surfaces (2) in the following called "joint surfaces". The stone surfaces are to resemble the visible surface of brick stones whereas the joint surfaces are intended to imitate the mortar forming the joints between the brick stones. The material is a plastics material which comprises a surface relief and a colour pattern consisting of various colours and nuances. The surface relief is deployed to create a difference of level so as to let the stone surfaces (1) lie in a roughly uniform first level whereas the joint surfaces (2) lie in a roughly uniform second level. In most cases it is preferred to have the joint surfaces at a lower level than the stone surfaces, although this relationship may be inverted if desired. Normally the stone surfaces are predominantly planar and, therefore, they will generally lie at the same level. The joint surfaces however, often show a certain profile either convex or concave as seen in a cross-section across the joint and the common level is better through of as an average level.

The product illustrative of the present invention is made to show rather naturally looking joint surfaces (2) by the application of a layer of granulate which is eminently suitable to imitate a mortar joint. The granulated material may be naturally or artifically coloured sand of the type normally used for joints. Refractory materials differ markedly from plastics materials, therefore zones of contact can show weaknesses such as insufficient adhesion. Also the refractory particles may show less desirable properties such as sharp edges causing abrasion, scratching or the accumulation of dirt.

These effects are controlled by the admixture of a thermoplastics material with the refractory particles such as PVC-particles. On heating, these PVC-particles sinter and join the refractory particles resulting in improved adhesion and in covering the refractory particles with a thin invisible plastics layer which smoothes out the surface. The embedding of the refractory particles into the plastics layer must not be taken to the point where it eliminates the structural appearance which is desired. An even more interesting variant replaces the refractory particles entirely by thermoplastics particles. If their size distribution is chosen suitably for the imitation of the mortar and if they contain suitably varied colours, surprisingly naturally looking joints are obtained by using plastics granules.The granules may be of several kinds such as more easily melting ones which constitute the sintering binder part for keeping the particles together and particles which melt at higher temperatures and are responsible for the structure. According to a preferred embodiment, however, all particles are of the same material which sinter by surface softening under the action of heat.

The main part of the granules may be coloured and/or opaque. Preferably, they are spherical and have diameters of 0.05-1.0 mm, especially 0.3-0.6 mm diameters are preferred.

Surface-covering materials formed from such preferably multicoloured plastics particles proved in actual trials to give non-scratching surfaces which do not collect dirt unduly and only marginally impede cleaning in comparison to a conventional surface. Incidentally it should be mentioned that the border lines of the joints need not be made with very great precision as such precision would not even be expected with a conventional joint of mortar.

The plastics particles are adhered to a surface in the areas for the joint surfaces (2). The colouring of the plastics material to be covered may be chosen to resemble the naturally or artificially coloured binder in the joint mortar which is intended to be imitated. In as much as the plastics material becomes visible between the particles it will contribute to the visual effect much as the interplay between the particulate material and the binder of a conventional joint mortar.

As regards the surface-covering material one preferred form of the invention lies in the construction of a colour and relief patterned plastics material where the material surfaces which are to resemble "stone surfaces" are formed by the colour and relief patterned plastics material whereas the joints are imitated by particles, preferably by particles in combination with the underlying plastics material which is coloured to give an optimal effect. The main reason for using particles is to give the joint a suitable appearance. At the same time the "feel" of the natural material is well imitated which might prove valuable in the case of wall-covering materials. It may also prove desirable in certain instances to allow particles to adhere to isolated parts of the "stone surfaces" to simulate small particle inclusions as can be seen in brick materials.

The use of plastics material suitable for relief patterning permits the joint surfaces (2) to have a level different from the stone surfaces (1). In the case of floor-covering materials, the joint surfaces are preferably on a lower level than the stone surfaces as in this case the traffic wear is distributed over a larger surface. Concomitantly, the layer of particles applied to the plastics surface is protected against abrasion. The joint surfaces covered by particles may also be used to reduce the slipperiness of a flooring material by increasing its friction. This is achieved whenever the lower joint surfaces are not too deep or too narrow. An even more effective protection against slipperiness is realized by joint surfaces lying at the same level as, or somewhat higher than, the stone surfaces between them.The levels can be chosen considerably more freely when producing wall coverings, the other major use for surfacecovering materials contemplated by the invention. Here it is possible to let convex joint surfaces protrude over and above the stone surfaces as sometimes can be seen in the case of brick and stone walls.

Figs. 2-4 show the successive construction of a surface-covering material illustrative of the invention during its fabrication. In Fig. 2 a substrate (3) such as non-woven glass is provided with a plastics layer (4) preferably made from a PVC-plastisol. To give it a consistency firm enough for the following steps in production the layer (4) is pregelled. Fig. 5 shows the final product in cross-section.

Fig. 3 shows the substrate formed from the pregelled layer (4) being provided with a coloured layer (5) which is to form the stone surfaces (1) and a coloured layer (6) which will form the joint surfaces (2). As the stone surfaces and the joint surfaces have to attain different levels the applied layers (5) and (6) must have a sufficient differentiating effect in addition to their colour effect. This may be achieved by several known methods.

One such method is to admix a blowing agent with the plastics layer (4). The coloured layers (5) and (6) comprise inhibitors or accelerators which control the foaming of the layer (4) when exposed to heat. The said inhibitors or accelerators are used in different concentra- tions or may be made to exercise their effect in some other way, resulting in differing foamability of the foaming layer (4) when it forms the stone surfaces and the joint surfaces, respectively. In addition to the two main lev els, a structured effect can be achieved so as to make the stone surfaces uneven (cf. Fig. 5) and the joint surfaces may be made convex (cf. Fig. 5). Generally, the foam-controlling coloured layers are applied by gravure printing as this method gives a wide variability of nuances.

Another method of achieving a height difference between the layers (5) and (6) is to use dissimilar plastics compositions with dissimilar foamability. Screen printing provides a method for such selective application of the similar and dissimilar areas and the said surface areas will attain different levels according to the foarnability of the respective composition during the latter heat-initiated foaming step. In addition they may be given different colours by incorporation of pigments into the various plastics compositions. Over and above this they may be provided with an overprinted colour shade pattern and it is even possible to combine both methods.In this case the main levels are attained by said application of selective areas of plastics compositions with dissimilar foamability whereas finer shades and surface texture are realized by the first method: in as much as they comprise a foamable plastics composition they are controllable by inhibitors or accelerators.

In a number of cases it is desirable that surface-covering materials of plastics, especially floorings, are protected by a transparent plastics layer, to protect the coloured layer.

Thus, Fig. 3 shows a PVC-plastisol layer (7).

The layer may be applied over the entire surface by doctor knife or screen printing.

However, it is necessary only on the stone surfaces (1) and can be applied there by screen printing. If high gloss and/or higher wear resistance is desirable, certain products may be provided with an acrylic or a polyurethane wear layer. Here, the wear layer suitably does not extend to cover the joint surfaces (2) as the following application of the particles would be impaired as adhesion onto polyurethane surfaces is markedly reduced. Therefore, it is necessary to apply the surface layer to the stone surfaces only by screen printing.

Because of the consecutive application of adhesive (cf. below) the layer must not be sticky and should be e.g. pregelled.

An adhesive (8) is applied to the areas (2), i.e. the joint surface. Preferably, screen printing is used as this gives easy control of register in relation to the earlier applied pattern, layers (5) and (6). The adhesive may be of the usual type based on volatile solvents or, preferably, PVC-plastisol which retains its adhesiveness as long as it is not exposed to heat and pregelled. Other suitable choices are one or two component setting adhesives. Still another alternative uses a hot melt adhesive, which get its adhesive properties when heated above a certain temperature and is non-adhesive below the said temperature. It is also possible to combine colouring agent inhibitor or accelerator and adhesive in one and the same composition and thereby save one printing step.

Next in the production follows the application of the particles to the surface. They will stick to the surfaces (2) as they are covered by the adhesive (8) and do not stick to the surfaces (1) which are free from adhesive and possess a relatively smooth gelled plastics layer (7). Superfluous material not having adhered to the adhesive (8) is removed by either turning the material upside-down, by brushing, vacuum-cleaning or by use of an air knife and only on the joint surfaces (2) a layer of particles 9 is retained as shown in Fig. 4.

In the case of hot melt adhesives, heating must be performed to make the adhesive sticky enough to retain the particles (9). This heating can be done as a part of the application of the adhesive or it may constitute a part of the heating step as described below.

Before the material has passed through all production steps it is the stickiness of the adhesive that ensures the particles be kept in place. Therefore, they must be relatively well anchored to the adhesive so as not to be dislocated when superfluous material is removed or during the other production steps.

To ensure this, the particles are pressed against the adhesive; either they are sprayed onto, or they are allowed to drop from a certain height against the surface or by vibrating the said surface. Still another method consists in pressing the particles into the adhesive with a soft roller.

After having brought together all components-the substrate (3), the various plastics materials and coloured layers (4-6), the wear layer (7) and the particulate material (9) stuck to the surface with adhesive (8),-the composite which may have a web shape is taken through a stove for heating. This results in the said foaming so as to give the web its relief pattern according to Fig. 5. Concomitantly, the final gelling of the plastics compositions takes place. If a plastisol is used as adhesive the particulate material (9) will be permanently combined with the substrate. In this way the above described material according to Fig. 1 is realized.

Depending on the type of adhesive used the setting of the adhesive may call for adequate steps such as radiation cure for a radiationcuring adhesive or time to evaporate the solvent.

If according to a preferred embodiment thermoplastics materials have been used as the particulate material the heating of these particles results in their combination with each other so as to give a relatively dirt-insensitive, dense surface even in the parts which are provided with a layer of particulate matter.

Different types of cohesion are realized depending on which material is chosen for the particulate material. Especially important is the melting point range. Again, a blend containing several different melting points may be used. This makes for a range from very weak sintering with limited surface softening of the particles over a more pronounced coalescence to the complete melting of certain particles thereby providing a matrix in which nonmelting particles are embedded. In this way the desired surface character and surface texture can be achieved.

There are several way of how the production of the material can be realized and hereinafter some examples will be given with reference to the accompanying drawings.

Example 1 A non-woven glass having a smooth precoated surface forms the substrate (3), and is coated with a PVC-plastisol containing a blowing agent. The plastisol is pregelled (cf. Fig.

2, layer 4).

This layer is printed with a multicolour decoration forming the stone surfaces (1) and the joint surfaces (2) respectively. The pattern resembles the surface forming by patterned ceramic tiles, each of them corresponding to a "stone surface" and individually decorated with a drawing. Some of the printing inks or colours which are intended to form small isolated parts of the stone surface contain a minor addition of inhibitor to control the blowing agent in layer 4 and to partly inhibit it.

The coloured layer forming the joint surfaces (2) contains an effective concentration of inhibitor in order to affect the blowing agent to a considerable degree and to inhibit the foaming. The coloured layers correspond to the layers (5) and (6) in Fig. 3; the print is applied by a gravure method.

On top of the printed colour decoration a layer of transparent plastisol is deposited, which corresponds to layer (7) in Fig. 3. This plastisol is pregelled.

To the parts of surface which are to form the joint surfaces (2), a plastisol corresponding to the adhesive layer (8) is applied by screen printing.

A layer of PVC-particles is deposited, their melting point being chosen so as to result in a coalescent surface layer during the following heat treatment. The particles have different colours and by this they form a naturally looking joint. A soft cylinder presses the particles against the material and thereby secures them to the joint surfaces (2) (layer 8). Vacuum nozzles remove the superfluous particles from the non-adhesive layer (7) of the stone surfaces (1).

Thereafter the material is put through a stove to be heated to a temperature of 1 80 C.

This gels the plastics layers, layer (8) inclusively, and the particulate material is firmly set in place. The particles sinter together and form a textured but cohesive surface. At the same time layer 4 is foamed and thereby the intended relief formed. A certain texture is noticeable on the stone surfaces as they show spots caused by the weak inhibitor of some of the inks used. This gives the impression of a coarse surface like that of some traditional stone materials, brick or the like. The blowing agent in the areas of joint surfaces is affected strongly and therefore the joint surfaces (2) are strongly depressed, cf. Fig. 5.

Example 2 A non-woven glass substrate (3) is printed with the pattern corresponding to the stone surfaces (1) with a PVC-plastisol containing blowing agent and applied by screen printing.

In order to resemble the pattern of a brick wall, cf. Fig. 1, both the thickness of the plastisol layer and the foamability of its plastics composition are calculated to form the thick parts of the product. The colour of the plastisol corresponds to the main colour of the stone surfaces. The plastisol is pregelled.

Then, a plastisol is applied in areas which are separated from each other and the surfaces of which are printed with a multicolour decoration intended to resemble the natural look of stone surfaces, when seen together with the base colour of the plastisol. The printing is a gravure print and the colours comprise an individually balanced type and concentration of inhibitor so that the fine texture of relief is formed during the foaming of the printed areas. No regard needs to be taken to the boundaries of the screen printed "plastisol islands" and the gravure printed multicolour decoration as this would not be expected from the brick wall the pattern is intended to imitate. This reasoning also holds true of walls made from natural stone whereas the out-of-register printing would not be applied to a product intended to resemble ceramic tiles with a decoration on each tile.In such cases, register must be provided for.

Using a screen, the plastisol islands are printed with a wear layer composition which after cross-linking results in a polyurethane layer as is known in the art. The application of the composition, however, is limited to the said surfaces only.

Weakly foamable plastisol corresponding to the adhesive layer (8) is screen printed onto the areas intended to form the joint surfaces (2), i.e. those parts of the substrate (3) which up to now remained uncoated. Thereafter, the surface is provided with a layer of PVC particles as described in Example 1.

In a following step, the plastics layers are gelled and cross-linked respectively as described in connection with Example 1. Again, a certain fine texture of the stone surfaces is obtained because of their being locally affected by the weak inhibitor used in some of the inks. The basic thickness of the stone surfaces is obtained by the foaming of the plastisol, applied as plastisol forming the joint surfaces serves both as a coating for the substrate and as an adhesive for the particulate material. After foaming, these areas are lower than the stone surfaces and in this way, the joints form the valley part of the product.

Claims (21)

1. A surface-covering material simulating an external surface showing geometrically shaped elements (A) of inorganic material joined by a mortar or other matrix material (B) comprising a binder and a particulate material, the surface-covering material comprising a relief patterned plastics material having a printed colour pattern and displaying areas (C), the areas (C) including the said shaped elements (A) positioned at a first level, and displaying interjacent areas (D) at a second level adjacent the first level, the areas (D) being shaped and positioned to resemble the said mortar or other matrix material (B), and the areas (D) forming a relief adjacent the areas (C), wherein the areas (C) are constituted by colour patterned visible surfaces of a plastics material and the areas (D) constitute a particulate material adhered to the surface of a plastics material by means of an adhesive and substantially covering the adhesive.

2. A surface-covering material according to Claim 1, wherein the elements (A) are bounded by a mortar or other matrix material (B).

3. A surface-covering material according to Claim 1 or Claim 2, wherein the elements (A) stimulate natural stones, bricks or other ceramic products.

4. A surface-covering material according to any preceding claim, wherein the particulate material comprises sand.

5. A surface-covering material according to any preceding claim, wherein the areas (D) are depressed relative to the areas (C).

6. A surface-covering material according to any preceding claim, wherein plastics material in the areas (D) is partly visible between and/or through the particles of the said particulate material, and the plastics material in the areas (D) is coloured so as to resemble the colour of the binder of the mortar or other matrix material to be simulated.

7. A surface-covering material according to any preceding claim, wherein the said particulate material comprises particles of coloured thermoplastics material.

8. A surface-covering material simulating an external surface substantially as herein described with reference to the accompanying drawings.

9. A method for producing a surface-covering material as defined in Claim 1, the method comprising coating a substrate with a foamable plastics composition displaying areas of dissimilar foamability corresponding to the said areas (C) and (D) respectively, thereby providing for the formation of the said first and second levels by foaming the plastics material and colour patterning of the said areas (C) and heating to cause foaming and formation of the end product, wherein an adhesive is printed on the plastics material in the pattern of the areas (D) in register with the decorative pattern of the areas (C), the said particulate material is applied to the surface of the plastics material while the adhesive is still in a sticky state, the said particulate material not attached to the adhesive is removed and the adhesive is solidified to retain the particulate material securely.

10. A method according to Claim 9, wherein the foamable plastics composition used for coating the said substrate is a PVCplastisol.

11. A method according to Claim 9 or Claim 10, wherein the said adhesive is a PVCplastisol.

1 2. A method according to Claim 11, wherein the said adhesive is a PVC-plastisol which is solidified by gelation during the said heating of the material.

1 3. A method according to any one of Claims 9 to 12, wherein the particulate material comprises thermoplastic particles, the thermoplast chosen having a melting range suitable for sintering to cause melting of the particles to coalesce without losing the particulate structure but sufficiently to form a textured yet dense surface.

14. A method according to Claim 13, wherein the particles range in size from 0.05-1.00 mm.

1 5. A method according to any one of Claims 9 to 14, wherein the said foamable plastics composition is applied as a plastics layer of uniform thickness to the said substrate, and is printed with said colour pattern by means of ink including inhibitor or accelerator for a blowing agent which is present so as to form both said first and second levels.

1 6. A method according to Claim 15, wherein the required structure or texture of at least the surfaces of areas (C) is obtained by diffentially controlled foaming of the plastics layer.

1 7. A method according to any one of Claims 9 to 16, wherein a layer of foamable plastics composition in the form of a plastisol is screen printed in regions defining areas (C) and a layer corresponding to areas (D) is applied as a second plastisol having a foamability different from that of the first plastisol.

1 8. A method according to Claim 17, wherein the first plastisol layer is provided with a colour pattern by means of ink comprising an inhibitor or accelerator for a blowing agent which is present so as to produce surfaces of areas (C) having a fine structure or texture during foaming of the said layer.

19. A method according to Claim 18, wherein the colour pattern is gravure printed without register with the pattern formed by partitioning the surface of the surface-covering material into areas (C) and (D).

20. A method according to Claim 9, substantially as herein described with reference to the accompanying drawings.

21. A surface-covering material which has been produced by a method as claimed in any one of Claims 9 to 20.