Technical field The invention relates to manufacturing a wall or floor covering, and methods for manufacturing the same.

State of the art

Floor elements made from polymer, but imitating natural parquet or ceramic tiles are widely known. However, it is a technical challenge to make these polymer floor elements imitate this parquet or these ceramic tiles as true to life as possible. Providing an irregular relief is also a challenge in itself.

Summary of the invention

In a first, independent aspect of the invention, a method for manufacturing a wall or floor covering is provided, comprising the following steps:

• Providing a substrate;

• Providing a foamable soft polymer film;

• Locally applying, for example printing, foam inhibitor on at least one side of the foamable soft polymer film;

• Bonding the foamable soft polymer film to the substrate;

• Foaming the foamable soft polymer film, wherein a first relief is provided on that side of the substrate which is provided with the foamed soft polymer film;

• Impressing a second relief on the side of the substrate which is provided with the foamed soft polymer film.

Locally applying means that the product is applied to one or more zones of the surface, and is not applied to one or more zones. The thickness of the foamable soft polymer film before foaming is typically in the range from range from 0.1 to 0.3 mm. After foaming, the foamable soft polymer film has a thickness which varies between the thickness of the still foamed foamable soft polymer film and 0.2 to 0.9 mm. The first relief thus has differences in thickness in the range between 0.1 to 0.6 mm. This first relief therefore possibly has a coarser pattern and deeper and wider troughs (1 to 4 mm) compared with the second relief. This second relief typically has troughs with a depth of between 0.05 and 0.5 mm and widths of 0.20 to 2 mm.

This second relief may be impressed with one or more pressure rollers provided with a surface relief, but may also be impressed digitally.

The expression soft polymer is understood to mean a polymer which comprises a significant amount of plasticizers, such as for example at least 40 phr of plasticizer. The acronym “phr” is understood to mean the amount of parts by weight of the component to 100 parts by weight of pure polymer matrix.

Bonding the foamable soft polymer film to the substrate may be achieved by means of thermal lamination.

According to some embodiments, the foamable soft polymer film may consist of soft PVC.

Soft PVC comprises 40 phr or more of plasticizers.

In the context of this invention, the phr of a component in a product means “parts per hundred resin”, which means the number of parts by weight of the component per hundred parts by weight of polymer - in this case PVC - in this product.

The plasticizers may inter alia be esters of carboxylic acids (for example esters of orthophthalic acid or terephthalic acid, trimellitic acid, benzoic acid and adipic acid), for example diisononyl phthalate (DINP), dioctyl terephthalate (DOTP), diisononyl cyclohexane-l,2-dicarboxylate (DINCH), esters of phosphoric acid, for example triaryl phosphates or trialkylaryl phosphates, for example tricresyl phosphate, optionally chlorinated hydrocarbons, ethers, polyesters, polyglycols, sulfonamides or combinations thereof. Possibly, the soft polymer, for example the soft PVC, may also comprise fillers (such as CaC03) or other additives (such as antioxidants, colorants, UV stabilizers and the like). Preferably, the soft polymer (for example soft PVC) comprises up to 200 phr of filler, for example CaC03.

The first and second relief are preferably in register. Here, in register means that the first and second relief together form a unit of deep and shallow troughs which forms a unit which gives a visually correct impression. The first and second relief may furthermore also be in register with the decorative pattern situated underneath.

The foam inhibitor is preferably printed at least on the side of the foamable soft polymer film, which side is turned away from the substrate. Thus, on the side which is not and will not be brought into direct contact with the substrate. However, according to an alternative, the foam inhibitor is printed at least on the side of the foamable soft polymer film, which side faces the substrate, i.e. on the side which will come into contact with the substrate.

According to some embodiments, the foam inhibitor may be applied, for example printed, on both sides of the foamable soft polymer film.

Foaming the foamable film is achieved by means of a thermal treatment. At locations where no inhibitor is present, this foamable film will largely or completely foam. Where there is foam inhibitor present, the film will only foam partly, a little or will not foam at all. After foaming of the foamable soft polymer, the foamed polymer may have a density of 0.3 to 0.8 kg/m ³ at the locations of maximum foaming. At the locations where the foamable polymer was prevented from foaming, the polymer which did not foam or which foamed incompletely may have a density of 1.0 to 1.8 kg/m ³ .

According to some embodiments, the foam inhibitor may be applied by means of digital printing, rotogravure printing or offset printing. According to some embodiments, the substrate may comprise at least one hard or semi- hard polymer layer.

The term hard polymer is understood to mean a polymer which comprises practically no plasticizers, such as for example between no and 10 phr of plasticizer. The term semi- hard (or semi-soft) polymer is understood to mean a polymer which comprises a relatively small amount of plasticizers, such as for example between 10 and 40 phr of plasticizer. Soft polymer comprises 40 phr or more of plasticizers.

Preferably, hard PVC (containing no or up to a maximum of 10 phr of plasticizers), or semi-hard PVC (containing plasticizers between 10 and 40 phr of plasticizers) is used.

Possibly, the hard or semi-hard polymer, for example the hard or semi-hard PVC, may also comprise fillers (such as CaC03) or other additives (such as antioxidants, colorants, UV stabilizers and the like). Preferably, the hard polymer (for example hard PVC) comprises up to 350 phr of filler, for example CaC03. Preferably, the semi-hard polymer (for example semi-hard PVC) comprises up to 250 phr or even more than 250 phr of filler, for example CaC03.

The substrate may consist of one layer of polymer or comprise several layers of polymer. The layers may be identical or differ from each other.

Thus, the substrate may comprise one hard or semi-hard polymer layer which is optionally foamed. The density is preferably chosen in a range from 1.5 to 2.3 kg/m ³ ; preferably 1.6 to 2.1 kg/m ³ in the case of an unfoamed polymer. The density is preferably chosen in a range from 0.5 to 1.5 kg/m ³ in the case of a foamed polymer, and preferably 0.8 to 1.3 kg/m ³ . Preferably, the foams are closed-cell foams. The polymer may be foamed by chemical foaming, physical foaming or be provided with closed cells by admixing hollow, optionally spherical, fillers.

The substrate may also, for example, comprise two layers, with one of the layers being foamed and the other one not and/or the substrate may also comprise, for example, two layers, with one of the layers being hard polymer and the soft or semi-hard being polymer.

In an alternative embodiment, the substrate may comprise, for example, three layers, wherein the two outer layers are harder than the middle layer.

In an alternative embodiment, the substrate may comprise, for example, three layers, wherein the two outer layers are denser, for example are unfoamed, whereas the middle layer is less dense, for example is foamed.

In an alternative embodiment, the substrate may comprise, for example, three layers, wherein the two outer layers are denser, for example are unfoamed and consist of a hard polymer, for example hard PVC, whereas the middle layer is less dense, for example is foamed and consists of a semi-hard or soft polymer, for example semi-hard or soft PVC. The substrate may also comprise more than three layers, wherein each of the layers may be foamed or not foamed and/or is a hard polymer or semi-hard polymer or soft polymer, wherein preferably one of the layers is a hard polymer.

Between or in the layer or layers, the substrate may comprise one or more reinforcing layers, for example textile reinforcing layers, for example consisting of a glass fiber- based textile product, for example a glass fiber woven or glass fiber nonwoven. The textile layer preferably comprises a glass fiber textile, for example a nonwoven glass fiber textile or a woven glass fiber textile. This glass fiber textile preferably has a weight per unit area from 15 to 120 g/m ² , such as from 25 to 55 g/m ² Preferably, a woven glass fiber textile has an open structure, for example a gauze structure or gauze woven. Preferably, the open space between successive warp or weft yarns may be between 1 mm and 1 cm.

Under the substrate, the wall element or floor element may optionally also comprise a backing layer, for example a soft polymer (for example PVC or PU) foam layer, or a textile fiber layer, for example a felt layer made of polymer fibers. According to some embodiments, the substrate may be made of PVC. In the context of the present invention, PVC is understood to mean the polymer polyvinyl chloride, copolymers of vinyl chloride and vinyl acetate, and combinations of both.

According to some embodiments, the substrate may be obtained by extruding polymer material to form a flat layer, melting particles made of polymer material to form a flat layer or calendering polymer material, such as PVC plastisols, to form a flat layer.

After providing the substrate, the method may comprise a step for calibrating the thickness of the substrate. This may be, for example, an additional pressing step or sanding the substrate or similar down to the desired thickness.

According to some embodiments, a decorative layer is applied to the foamable soft polymer film between the step of bonding the foamable soft polymer film to the substrate and foaming the foamable soft polymer film, the decorative layer comprising a decorative image. The decorative layer may be printed onto the foamable soft polymer film, preferably by digital printing, rotogravure printing or offset printing.

This printing of the decorative layer with the associated decorative image may take place before the foamable soft polymer film is bonded to the substrate, optionally even at the same time as the foam inhibitor is applied, for example by printing. In an alternative embodiment, the foamable soft polymer film is first bonded to the substrate, after which the decorative layer is printed onto the foamable soft polymer film.

In another alternative embodiment, the foamable soft polymer film is first bonded to the substrate, after which the foam inhibitor is printed on on the side facing away from the substrate, optionally at the same time, before or after the decorative layer is printed on.

According to some embodiments, the decorative layer may be applied by bonding a printed film to the foamable soft polymer film.

Said bonding may be carried out by means of thermal lamination.

The printed film is preferably a PVC printed film, more preferably made of hard PVC. According to some embodiments, a transparent wear layer may be applied after the decorative layer has been applied.

The wear layer is preferably a PVC transparent film. Although it is possible to use hard PVC, this PVC transparent film is more preferably made of semi-hard or soft PVC. Preferably, less than 40 phr of plasticizer is used, most preferably in the range from 25 to 35 phr.

According to some embodiments, a transparent wear layer may be bonded to the side of the printed film which will not come into contact with the foamable soft polymer film before the decorative layer is applied to the foamable soft polymer film.

Said application may be carried out, for example, by thermal lamination.

According to some embodiments, the decorative image and the first relief may be in register.

According to some embodiments, the decorative image and the second relief may be in register.

One or both reliefs are in register with the decorative image, meaning that the first and/or second relief follows the decorative image, for example where the image creates an illusion of a recessed zone, one or both reliefs will also feature a trough, at least partly.

The resultant product may first be cut into rectangular elements and may have, for example, the appearance of boards or tiles, wherein for example the decorative image depicts a wood structure or a ceramic, concrete, stone or marble structure. The rectangles may have beveled edges along part or all of their periphery. These beveled edges may be provided by there being locally no or little foaming of the foamable soft polymer film as a result of the application of the foam inhibitor. In this case, the decorative image shows corresponding rectangular elements. By bringing the decorative image and the first relief into register, the foam inhibitor may thus be used to provide the technical zones in case boards or tiles are to be produced from the intermediate product. These are zones on the sides of the boards or tile-shaped peripheries, where the various surfaces are cut or sawn apart by sawing or cutting, and in which zones the coupling means are possibly also provided by, for example, milling. By also placing the second relief in register with the first relief and the decorative image, it is also possible to provide a finer relief in the of the first relief deeper zones and in the technical zones and this second relief may, for example, be used to provide the bevel of the tiles or boards. In this case, the beveled edge is additionally pressed on by the second relief on the previously rounded side edges of the first relief at the location of the technical zones.

According to some embodiments, the decorative image may depict rectangular elements, the foam inhibitor is at least applied, for example printed, along at least a part of the peripheries of the rectangular elements.

Since the inhibitor has prevented foaming along at least part of the periphery, a slanting edge is provided at those locations along the periphery.

In a further step, the rectangular wall or floor covering elements may be provided with a tongue and groove click-fit system in a known manner.

According to some embodiments, the foamable soft polymer film may be foamed by treating it with thermal energy.

Foaming of the foamable soft polymer film may be carried out by thermal treatment of the foamable soft polymer film which is bonded to the substrate, for example by thermally treating it in a hot-air oven or infrared oven.

According to some embodiments, the foamable soft polymer film may comprise azodicarbonamide (ADCA) as the foaming component. The foaming components are preferably present in an amount of between 0.5 and 4 phr, more preferably between 1.5 and 2.5 phr.

According to some embodiments, the foam inhibitor may comprise one or more components selected from the group consisting of thiourea, for example thioureum, and triazoles, for example benzotriazole.

The amount of foam inhibitor may vary from location to location across the surface of the foamable soft polymer film. Thus, the foamable soft polymer film will foam completely where no inhibitor is present, and locally gradually foam less as more foam inhibitor is present in said location. Thus, it is possible to obtain a relief with different local thicknesses. The amount of foam inhibitor thus varies between no inhibitor and a maximum amount of inhibitor, the foamable soft polymer film not foaming at all when this maximum amount of inhibitor is present. This maximum amount of inhibitor is linked to the amount of foaming components in the foamable soft polymer film.

According to some embodiments, a layer of lacquer may be applied to the surface provided with the second relief after the second relief has been impressed.

The layer of lacquer preferably has a thickness of between 5 pm and 30 pm. The layer of lacquer may consist of a UV-curing lacquer.

In an alternative embodiment, the layer of lacquer is applied first before a second relief is impressed.

After the second relief has been impressed and optionally after further steps, such as applying a layer of lacquer, the resultant product may already be the wall or floor covering element according to the invention.

According to a second independent aspect of the invention, a method for producing a layered wall or floor covering is provided, comprising the following steps: • Locally applying on at least one side, for example printing, a foam inhibitor on a foamable polymer film;

• Incorporating the foamable polymer film as a layer in the layered structure;

• Foaming the foamable polymer film.

According to some embodiments, foam inhibitor may be locally applied, for example printed, on both sides of the foamable polymer film.

According to some embodiments, the foamable polymer film may be a foamable soft PVC film.

A third, independent aspect of the invention provides the use of foamable polymer film to one or both sides of which foam inhibitor has been locally applied, for example by printing, in a process for producing a wall or floor covering.

It will be clear that the characterizing features of embodiments of the first aspect may be used for the object of the second and/or third aspect of the invention. It will be clear that the characterizing features of embodiments of the second aspect may be used for the object of the first and/or third aspect of the invention.

The independent and dependent claims describe specific and preferred characterizing features of the embodiments of the invention. Characterizing features of the dependent claims may be combined with characterizing features of the independent and dependent claims, or with characterizing features described above and/or below, in any suitable way as would be obvious to someone skilled in the art.

The above and other characterizing features, properties and advantages of the present invention will be explained by means of the following exemplary embodiments, optionally in combination with the drawings.

The description of these exemplary embodiments is given for the purpose of clarification, without intending to limit the scope of the invention. The reference numerals in the following description refer to the drawings. Identical reference numerals in possibly different figures refer to identical or similar elements.

Brief description of the figures With a view to providing a better illustration of the characterizing features of the invention, the following text describes a number of preferred embodiments by way of example and without any limiting nature, with reference to the attached drawings, in which: · Figure 1 is an illustration of a production method according to aspects of the invention.

• Figure 2 diagrammatically shows a cross section of the resultant product according to the invention. Description of exemplary embodiments

The present invention is described below by means of specific embodiments.

It should be noted that the term "comprising", as used, for example, in the claims, should not be interpreted in a limiting sense, limited to the elements, characterizing features and/or steps mentioned thereafter. The term "comprising" does not exclude presence of other elements, characterizing features or steps.

Thus the scope of an expression "an object comprising the elements A and B", is not limited to an object which contains only the elements A and B. The scope of an expression "a method comprising the steps A and B" is not limited to a method which contains only the steps A and B.

In the light of the present invention, these expressions mean only that the relevant elements and steps, respectively, are the elements and steps A and B, respectively, for the invention. In the following specification, reference is made to "an embodiment" or "the embodiment". Such a reference means that a specific element or characterizing feature, described by means of this embodiment, is comprised in at least this one embodiment.

However, when the terms "in an embodiment" or "in the embodiment" are used at various points in this description, these do not necessarily refer to the same embodiment, although it may nevertheless refer to the same embodiment.

Furthermore, the properties of the characterizing features may be combined in one or more embodiments in any suitable manner, as will be clear to those skilled in the art.

A method for manufacturing a wall or floor covering is illustrated diagrammatically in Figure 1.

On the one hand, a substrate 101 is provided by means of extrusion with a flat mold extruder 11. A hard PVC layer is extruded using extruder 11 and is stabilized initially in stabilizing station 12. The extruded PVC foams in this stabilizing station to form a substrate 101 having a density of between 0.8 and 1.8 kg/1. The thickness of the substrate is approximately 4 mm. It is made of hard PVC with an amount of less than 10 phr of plasticizer, and 100 to 300 phr of fillers, for example 200 phr of filler.

In an alternative embodiment, a substrate is provided in the form “ABA”, in which two rigid, unfoamed PVC layers (layers A) are in each case positioned on a side of a foamed PVC layer (layer B). The compositions of the PVC in layers A are identical to those described above, but have a thickness of approximately 0.8 mm and are not foamed. The density is approximately 2.1 kg/1. The compositions of the PVC in layer B is identical to those described above and has a thickness of 2.4 mm.

In another alternative embodiment, the B layer is made from soft, optionally foamed PVC.

In rolling station 13, the thickness of the substrate 101 is calibrated by means of pressure rollers. On the other hand, a foamable soft polymer film 102 is provided, for example on a roll. This foamable soft polymer film 102 may be produced using, for example, a calendering device (not shown). In an alternative arrangement, the film 102 is supplied directly from such a calendering device.

In a first printing station 21, a foam inhibitor 103 is printed on side 102a of the foamable soft polymer film 102. The foam inhibitor is thioureum or a tri azole-based component and is printed using water as a carrier. In dryer 22, the foam inhibitor is dried on side 102a using IR.

In a second printing station 23, a foam inhibitor 104 is printed on side 102b of the foamable soft polymer film 102. The foam inhibitor is the same as foam inhibitor 103. In dryer 24, the foam inhibitor is dried on side 102b using IR.

In this way, a foam inhibitor is applied locally, on both sides 102a and 102b, which will locally prevent foaming during foaming of the foamable soft polymer film 102 and will thus create a relief in the foamed polymer film.

The foamable soft polymer film 102 and the substrate 101 are passed to a laminator 25 where both are bonded together by means of pressure and temperature. In this way, an intermediate 103 is formed consisting of the substrate layer 101 with the foamable soft polymer film 102 bonded thereto.

In a further laminator 26, a pre-printed film 104 featuring a decorative image is laminated on. The film 104 is made from hard PVC and thus contains an amount of less than 10 phr of plasticizer. The thickness is approximately 80 to 90 pm.

In the same further laminator 26, a transparent wear film 105 is laminated onto the film 104. The wear film 105 is made of semi-hard PVC containing an amount of plasticizers of between 10 and 40 phr. The wear film 105 does not comprise any fillers and is transparent. The wear layer 105 is not foamed. After the decorative film 104 and wear film 105 have been applied, the intermediate 106 is subjected to a thermal treatment, for example in a hot-air oven 27. This causes foaming of the foamable soft polymer film 102 whereby, due to the presence of foam inhibitors, a first relief is provided on that side of the substrate which is provided with the foamed soft polymer film. In this way, an intermediate product 107 is obtained which is composed of the substrate 101 with the foamed version of the foamable soft polymer film 102, the decorative film 103 and the wear film 104 on top thereof.

Impressing a second relief on that side of the substrate which is provided with the foamed soft polymer film takes place in the so-called “embossing station” 28 by pressing a pressure roller comprising the relief (roller 29) to be impressed against the surface of the intermediate 107.

After the second relief has been impressed in station 30, a layer of lacquer 109 is applied, made from UV-curing PU (polyurethane). The thickness of the layer of lacquer, or coating, is approximately 15 pm.

Figure 2 shows a cross section of the resultant product 108 along the plane AA’. The effect of the local presence of varying amounts of foam inhibitor can clearly be seen here.

Zone 201 contained the maximum amount of foam inhibitor and no foam developed. In the zones 202, there was a gradual variation from the maximum amount of foam inhibitor to no inhibitor. The effect is that in these zones 202 the foam of the foamable soft polymer film 102 developed gradually. In the zones 203, no foam inhibitor was present and the foam of the foamable soft polymer film 102 was able to develop fully. In specific zones 204, a small amount of foam inhibitor was present and the foam only partly developed. The alternating zones 201 to 204 together form the first relief. The depth of this relief is of an order of magnitude of 400 pm and more.

In the zones 203, the pressure roller 29 had the possibility of impressing a second relief. This relief is much finer than the first relief. The depth of this second relief is of an order of magnitude of 50 to 300 pm. If the decorative film 103 depicts, for example, wooden boards, the zones 202 to 204 together may represent the width of the board.

In this way, it is possible to saw or cut boards from the product 108 using the zones 201 as technical zones, in which the sawing/cutting may take place. The zones 202 then represent the beveled edges of the board. The parts 203 and 204 of the first relief together with the second relief in the zones 203 may then give the impression of woodgrain and the like. This is particularly attractive for the user if the decorative image and these parts of the reliefs follow one another, i.e. are in register with each other.

It will be clear that, although the embodiments and/or the materials for producing embodiments according to the present invention have been described, various modifications or changes may be made without departing from the area of application and/or the spirit of this invention. The present invention is by no means limited to the above-described embodiments, but may be realized by means of different variants without departing from the scope of the present invention.