BE1027842A1 - METHOD FOR MAKING WALL OR FLOOR COVERING - Google Patents

Abstract

A method of making wall or floor coverings comprising the steps. - Providing a substrate; - Providing a foamable soft polymer foil; - Local application, e.g. printing, of foam inhibitor on at least one side of the foamable soft polymeric film; - bonding the foamable soft polymeric film to the substrate; - foaming the foamable soft polymeric film, wherein a first relief is provided on the side of the substrate provided with the foamed soft polymeric film; - Impression of a second relief on the side of the substrate provided with the foamed soft polymeric film.

Description

METHOD FOR MAKING WALL OR FLOOR COVERING Technical Field The invention is related to the manufacture of wall or floor coverings, and methods of making such.

State of the art Floor elements made of polymer, but imitating natural parquet or ceramic tiles, are well known.

However, it is technically a challenge to imitate these parquet or ceramic tiles as faithfully as possible as naturally as possible.

Providing an irregular relief in itself is also a challenge.

Summary of the Invention In a first, independent aspect of the invention there is provided a method of making wall or floor coverings comprising the steps of e Providing a substrate;

e Providing a foamable soft polymer film;

e Topically applying, e.g. printing, foam inhibitor to at least one side of the foamable soft polymeric film;

e Bonding the foamable soft polymeric film to the substrate;

e foaming the foamable soft polymeric film, wherein a first relief is provided on the side of the substrate provided with the foamed soft polymeric film;

e Impression of a second relief on the side of the substrate provided with the foamed soft polymeric film.

Topically or locally applied means that the product is applied to one or more areas of the surface, and is not applied to one or more areas.

The thickness of the foamable soft polymeric film, before foaming, is typically in the range of 0.1 to 0.3 mm.

After foaming, the foamable soft polymeric film has a thickness varying between the thickness of the still foamed foamable soft polymeric film and 0.2 to 0.9 mm.

The first relief thus comprises thickness differences in the range between 0.1 to 0.6 mm.

This first relief may therefore have a rather coarser pattern and deeper and wider valleys (1 to 4 mm) compared to the second relief.

This second relief typically has valleys with depths between 0.05 and 0.5 mm and widths of 0.20 to 2 mm.

This second relief can be pressed with one or more pressure rollers provided with a profile, but can just as well be pressed digitally.

By soft polymer is meant a polymer comprising a significant amount of plasticizers, such as, for example, at least 40 phr plasticizer.

By "phr" is meant the amount by weight of the component, per 100 parts by weight of pure polymer matrix.

Bonding of the foamable soft polymeric film to the substrate can be accomplished by thermal lamination.

In some embodiments, the foamable soft polymeric film may be soft PVC.

Soft PVC comprises 40 phr or more plasticizers.

Phr of a component in a product in the context of this invention means "parts per houndred 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 include esters of carboxylic acids (e.g. esters of ortho- or terephthalic acid, trimelitic acid, benzoic acid and adipic acid), e.g. diisononyl phthalate (DINP), dioctyl terephthalate (DOTP), di-isononyl-1,2-cyclohexanedicarboxylate (DINCH ), esters of phosphoric acid, for example triaryl or trialkylaryl phosphates, for example tricresyl phosphate, or non-chlorinated hydrocarbons, ethers, polyesters, polyglycols, sulfonamides, or combinations of these.

Possibly the soft polymer, for example the soft PVC, may also comprise fillers (such as CaCO3) or other additives (such as antioxidants, colorants, UV stabilizers and the like). Preferably the soft polymer (e.g. soft PVC) comprises up to 200 phr filler, e.g. CaCO 3 .

The first and second reliefs are preferably in register.

In register means here that the first and second relief together form a whole of deep and shallow valleys, which forms a visually correct feeling whole.

The first and second relief may furthermore also be in register with the underlying decorative pattern.

The foam inhibitor is preferably printed on at least the side of the foamable soft polymeric film which faces away from the substrate.

So on the side that is not or will not be brought into direct contact with the substrate.

In an alternative form, however, the foam inhibitor is printed on at least the side of the foamable soft polymeric film, which side faces the substrate, i.e. on the side that will come into contact with the substrate.

In some embodiments, the foam inhibitor can be applied, e.g. printed, to both sides of the foamable soft polymeric film.

The foaming of the foamable foil is accomplished by a thermal treatment.

Where no inhibitor is present, this foamable film will foam largely or completely.

Where foam inhibitor is present, the foil will foam only partially, little or not at all.

After foaming the foamable soft polymer, the foamed polymer can have a density or density of 0.3 to 0.8 kg/m2 at the maximum foaming level. to have.

At the locations where the foamable polymer was prevented from foaming, the unfoamed or incompletely foamed polymer may have a density of 1.0 to 1.8 kg/m.

In some embodiments, application of the foam inhibitor may be by digital printing, rotogravure printing, or offset printing. In some embodiments, the substrate may comprise at least one hard or semi-rigid polymer layer.

By hard polymer is meant a polymer which contains almost no plasticizers, such as, for example, between none and 10 phr plasticizer.

By semi-hard (or semi-soft) polymer is meant a polymer which comprises a relatively small amount of plasticizers, such as for instance between 10 and 40 phr plasticizer. Soft polymer comprises 40 phr or more plasticizers.

Preferably rigid PVC (with no or up to 10 phr plasticizers, or semi-rigid PVC (with plasticizers between 10 and 40 phr plasticizers) is used.

Possibly the hard or semi-rigid polymer, for example the hard or semi-rigid PVC, may also comprise fillers (such as CaCO3) or other additives (such as antioxidants, colorants, UV stabilizers and the like). Preferably the hard polymer (e.g. hard PVC) comprises up to 350 phr filler, e.g. CaCO 3 . Preferably the semi-rigid polymer (e.g. semi-rigid PVC) comprises up to 250 phr or even more than 250 phr of filler, e.g. CaCO 3 .

The substrate may consist of one layer of polymer, or comprise multiple layers of polymer. The layers can be identical or different from each other.

Thus, the substrate may comprise one hard or semi-rigid polymer layer which may or may not be foamed. Density is preferably selected in a range of 1.5 to 2.3 kg/m°; preferably 1.6 to 2.1 kg/m? in case of unfoamed polymer. Density is preferably chosen in a range of 0.5 to 1.5 kg/m? in the case of foamed polymer, and preferably 0.8 to 1.3 kg/m 3 . Preferably the foams are closed foams. The polymer can be foamed by chemical foaming, physical foaming or provided with closed cells by admixing hollow, whether or not spherical, fillers. For example, the substrate may also comprise two layers, where one of the layers is foamed and the other is not, and/or the substrate may also comprise, for example, two layers, where one of the layers is hard polymer and it is soft or semi-rigid polymer.

For example, in an alternative embodiment, the substrate may comprise three layers, with the two outer layers being harder than the middle layer.

For example, in an alternative embodiment, the substrate may comprise three layers, with the two outer layers being more dense, e.g. unfoamed, while the middle layer is less dense, e.g. foamed.

For example, in an alternative embodiment, the substrate may comprise three layers, the two outer layers being more dense, e.g., unfoamed, and composed of hard polymer, e.g., rigid PVC, while the middle layer is less dense,

e.g. is foamed and consists of semi-rigid or soft polymer, e.g. semi-rigid or soft PVC.

The substrate may also comprise more than three layers where each of the layers may be foamed or non-foamed, and/or be hard polymer or semi-hard polymer or soft polymer, preferably one of the layers is hard polymer. Between or in the layer or layers, the substrate may comprise one or more reinforcement layers, for example textile reinforcement layers, for example consisting of a glass fiber based textile product, for example a glass fiber fabric or glass fiber fleece. 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 of from 15 to 120 g/m², such as from 25 to 55 g/m². Preferably, a woven glass fiber textile has an open structure, for example a mesh structure or mesh fabric. Preferably, the open space between successive warp or weft yarns can be between 1 mm and 1 cm. Below the substrate, the wall or floor element may optionally further comprise a backing layer, for instance a soft polymeric (for example PVC or PU) foam layer, or a textile fiber layer, for example a felt layer from polymeric fibres.

In some embodiments, the substrate may be formed from PVC. For the purposes of this invention, PVC refers to the polymer polyvinyl chloride, copolymers of vinyl chloride and vinyl acetate, and combinations of both.

In some embodiments, the substrate may be obtained by extruding polymeric material into a planar layer, fusing polymeric material particles into a planar layer, or calendering polymeric material into a planar layer, such as PVC plastisols.

After providing the substrate, the method may include a step for calibrating the thickness of the substrate. This can be, for example, an extra pressing step, or sanding the substrate to thickness or the like.

In some embodiments, between the step of bonding the foamable soft polymeric film to the substrate and foaming the foamable soft polymeric film, a decorative layer may be applied to the foamable soft polymeric film, the decorative layer having a decorative image. The decorative layer can be printed on the foamable soft polymeric film, preferably by digital printing, rotogravure printing or offset printing. This printing of the decorative layer with associated decorative image can take place before the foamable soft polymeric foil is bonded to the substrate, possibly even simultaneously with the application, for example by printing, of the foam inhibitor. In an alternative embodiment, the foamable soft polymeric film is first bonded to the substrate, after which the decorative layer is printed on the foamable soft polymeric film.

In yet another alternative embodiment, the foamable soft polymeric film is first bonded to the substrate, after which it is printed, or printed, on the side remote from the substrate, with the foam inhibitor, optionally simultaneously, before or after printing of the decorative low.

In some embodiments, the decorative layer may be applied by bonding a printed film to the foamable soft polymeric film. This bonding can be done by thermal lamination.

The printed film is preferably a PVC printed film, more preferably of rigid PVC.

In some embodiments, after applying the decorative layer, a transparent wear layer can be applied.

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

In some embodiments, a transparent wear layer may be bonded to the side of the printed film that will not contact the foamable soft polymeric film before the decorative layer is applied to the foamable soft polymeric film.

This application can take place, for example, by thermal lamination.

In some embodiments, the decorative image and the first relief may be in register. In some embodiments, the decorative image and the second relief may be in register. One or both reliefs are in register with the decorative image, this means that the first and/or second relief follows the decorative image, for example where the image creates an illusion of a sunken zone, one or both reliefs will also show a valley at least partly . The product obtained can first be cut into rectangular elements and, for example, have the appearance of planks or tiles, where, for example, the decorative image represents a wood structure or a ceramic, concrete, stone or marble structure. The rectangles may have chamfered edges along part or all of their perimeter. These chamfered edges can be provided by locally not or little foaming of the foamable soft polymeric foil by applying the foam inhibitor. In this case, the decorative image displays corresponding rectangular elements.

Thus, by registering the decorative image and the first relief, the foam inhibitor can be used to provide the technical zones, in case planks or tiles are to be manufactured from the intermediate product. These are zones on the sides of the planks or tile-shaped perimeters, where surfaces that are too different from each other are cut or sawn by means of sawing or cutting, and in which zones the coupling means may also be provided, for example, by milling. By also placing the second relief in register with the first relief and the decorative image, a finer relief can be provided in the deeper zones of the first relief and in the technical zones, and this second relief can, for example, be used to make the chamfer. (also known as “command”) of the tiles or planks. In this case, the chamfered side is additionally pressed by the second relief on the previously rounded sides of the first relief at the height of the technical zones.

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

Since the inhibitor has prevented foaming along at least part of the circumference, a bevel is provided at those places along the circumference.

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

In some embodiments, the foamable soft polymeric film may be foamed by thermal energy treatment.

The foaming of the foamable soft polymeric film can be done by thermally treating the foamable soft polymeric film bonded to the substrate, for example by thermally treating in a hot air oven or infrared oven.

In some embodiments, the foamable soft polymeric film may comprise as the foam-forming component Azodicarbonamide (ADCA). The foam-forming components are preferably present in an amount of between 0.5 and 4 phr, more preferably between 1.5 and 2.5 phr .

In some embodiments, the foam inhibitor may comprise one or more components selected from the group consisting of thioureas, e.g., thiourea, and triazoles, e.g., benzotriazole.

The amount of foam inhibitor may vary from location to location across the surface of the foamable soft polymeric film. Thus, the foamable soft polymeric film will foam completely where no inhibitor is present, foaming gradually less locally the more foam inhibitor is present at that location. Thus, a relief of different local thickness can be obtained. Thus, the amount of foam inhibitor varies between no inhibitor and a maximum amount of inhibitor, with the foamable soft polymeric film not foaming at all in the presence of this maximum amount of inhibitor. This maximum amount of inhibitor is related to the amount of foam-forming components in the foamable soft polymeric film.

In some embodiments, after pressing the second relief, a coat of lacquer may be applied to the surface provided with the second relief. The lacquer layer preferably has a thickness of between 5 µm and 30 µm. The lacquer layer may consist of UV-curing lacquer. In an alternative embodiment, the lacquer layer is applied first before a second relief is printed. After the second relief has been pressed in, and optionally after further steps such as applying a lacquer layer, the product obtained can already be the wall or floor covering element according to the invention. According to a second independent aspect of the invention, there is provided a method of manufacturing a layered wall or floor covering, comprising the steps of e locally applying, e.g. printing, on at least one side a foamable polymeric film with a foam inhibitor; e Incorporation of the foamable polymeric film as a layer in the layered structure; e Foaming the foamable polymer film. In some embodiments, the foamable polymeric film can be topically applied, e.g., printed on both sides with foam inhibitor.

In some embodiments, the foamable polymeric film may be a foamable soft PVC film. A third, independent aspect of the invention provides the use of a foam inhibitor locally applied on one or both sides, for example printed, foamable polymeric film in a process for the manufacture of wall or floor coverings. It is apparent that the features of embodiments of the first aspect can be applied to the subject matter of the second and/or third aspect of the invention. It is apparent that the features of embodiments of the second aspect can be applied to the subject matter of the first and/or third aspect of the invention.

The independent and dependent claims set forth specific and preferred features of the embodiments of the invention. Features of the dependent claims may be combined with features of the independent and dependent claims, or with features described above and/or below, in any suitable manner as would be apparent to a person skilled in the art.

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

The description of these exemplary embodiments is provided by way of illustration, without intent to limit the scope of the invention. The reference numerals in the following description refer to the drawings. Same reference numbers in possibly different figures refer to identical or similar elements.

Brief description of the figures With the aim of better demonstrating the features of the invention, some preferred embodiments are described below, by way of example without any limiting character, with reference to the accompanying drawings, in which:

e Figure 1 is a representation of a production method according to aspects of the invention. e Figure 2 shows schematically a cross-section of the product obtained according to the invention. Description of Embodiments Examples The present invention is described below using 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, limiting to the following elements, features and/or steps. The term "comprising" does not exclude the presence of other elements, features or steps.

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

In the light of the present invention, these terms mean only that the relevant elements and steps respectively for the invention are the elements A and B respectively.

In the following specification reference is made to "an embodiment" or "the embodiment". Such reference means that a specific element or feature described with reference to this embodiment is included in at least this one Embodiment.

However, the occurrence of the terms "in an embodiment" or "in the embodiment" in various places in this specification does not necessarily refer to the same embodiment, although it may refer to a same embodiment.

Furthermore, the features or features may be combined in any suitable manner in one or more embodiments, as would be apparent to those skilled in the art. A method for making wall or floor coverings is schematically shown in Figure 1. On the one hand, a substrate 101 is provided by extrusion with a flat mold extruder.

11. A hard PVC layer is extruded with extruder 11 and is initially stabilized in stabilization station 12. The extruded PVC foams in this stabilization station to a substrate 101 with a density between 0.8 and 1.8 kg/l. The thickness of the substrate is about 4 mm. It is made of rigid PVC with an amount of less than 10 phr plasticizer, and 100 to 300 phr fillers, e.g. 200 phr filler.

In an alternative embodiment, a substrate is provided with the shape "ABA", wherein two rigid, non-foamed PVC layers (layers A) are positioned each time on one side of a foamed layer of PVC (layer B). The compositions of the PVC in layers A are similar to those described above, but have a thickness of approximately

0.8mm and are not foamed. The density is about 2.1 kg/l. The composition of the PVC in layer B is similar to that described above, and has a thickness of 2.4 mm. In yet another alternative embodiment, the B layer is made of soft, foamed or non-foamed PVC.

In the rolling station 13, the thickness of the substrate 101 is calibrated by means of pressure rollers. On the other hand, a foamable soft polymeric film 102 is provided, for example on a roll. This foamable soft polymeric film 102 may be made with, for example, a calender (not shown). In an alternative arrangement, the film 102 is fed directly from such a calender. In a first printing station 21, the foamable soft polymeric film 102 is printed on side 1024 with a foam inhibitor 103. The foam inhibitor is thiourea or a triazole based component and is printed with water as carrier. The foam inhibitor is dried on side 102a with IR in dryer 22. In a second print station 23, the foamable soft polymeric film 102 is printed on side 102b with a foam inhibitor 104. The foam inhibitor is the same as foam inhibitor 103. The foam inhibitor is dried on side 102b with IR in dryer

24. Thus, a foam inhibitor is applied locally to both sides 1024 and 102b which, when foaming the foamable soft polymeric film 102, will locally prevent this foaming and thus create a relief in the foamed polymeric film. The foamable soft polymeric film 102 and the substrate 101 are passed to a laminator 25 where both are bonded together by means of pressure and temperature. Thus, an intermediate 103 is formed consisting of the substrate layer 101 with the foamable soft polymeric film 102 bonded thereto. In a further laminator 26, a preprinted film 104 bearing a decorative image is laminated. The film 104 is made of rigid PVC and thus has an amount of less than 10 phr of plasticizer. The thickness is about 80 to 90 µm. In the same further laminator 26, a transparent wear film 105 is further laminated to the film 104. The wear film 105 is made of semi-rigid PVC with an amount of plasticizers between 10 and 40 phr. The wear film 105 contains no fillers and is transparent. The wear layer 105 is not foamed. After application of the decorative film 104 and wear film 105, the intermediate 106 is subjected to a thermal treatment, for example in a hot air oven.

27. This causes the foaming of the foamable soft polymeric film 102 whereby the side of the substrate having the foamed soft polymeric film is provided with a first relief due to the presence of foam inhibitors. Thus, an intermediate product 107 is obtained comprising the substrate 101, thereon the foamed version of the foamable soft polymeric film 102, the decorative film 103 and the wear film 104.

Impression of a second relief on the side of the substrate provided with the foamed soft polymeric film is done in the so-called “embossing station” 28 by pressing a pressure roller with the relief to be pressed (roll 29) against the surface of the intermediate 107. to push.

After this impression of the second relief, a lacquer layer 109 is applied in station 30, made of UV-curing PU (polyurethane). The thickness of the lacquer layer, or coating, is approximately 15 µm.

In Fig. 2 is shown a cross-section of the obtained product 108 along the plane AA'. The effect of the local presence of varying amounts of foam inhibitor can be clearly seen here.

In zone 201, the maximum amount of foam inhibitor was present, and no foam built up. In 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 polymeric film 102 has gradually built up. In zones 203, no foam inhibitor was present and the foam of the foamable soft polymeric film 102 was allowed to develop completely. In specific zones 204, a small amount of foam inhibitor was present and the foam only partially developed. The alternating zones 201 to 204 together form the first relief. The depth of this relief is of a magnitude of 400 µm and greater.

In the zones 203, the pressure roller 29 has had the opportunity to emboss a second relief. This relief is much finer than the first relief. The depth of this second relief is in the order of 50 to 300 µm.

For example, when the decorative film 103 depicts wooden planks, the zones 202 to 204 together may represent the width of the plank.

Planks can thus be sawn or cut from the product 108, using the zones 201 as technical zones, where the (saw) cut can take place. The zones 202 then represent the chamfered sides of the shelf. The parts 203 and 204 of the first relief, together with the second relief on the zones 203, can then give the impression of the wood grains and the like. This is particularly attractive to the user if the decorative image and these parts of the reliefs follow each other, i.e. are in register with each other.

It is understood that while the embodiments and/or the materials for furnishing embodiments of the present invention have been discussed, various modifications or changes may be made without departing from the scope and/or spirit of this invention.

The present invention is by no means limited to the embodiments described above, but can be realized according to various variants without departing from the scope of the present invention.

_ invention to act.

Claims (1)

Conclusions 1.- A method of making wall or floor coverings, comprising the steps of e Providing a substrate; e Providing a foamable soft polymer film; e Topically applying, e.g. printing, foam inhibitor to at least one side of the foamable soft polymeric film; e Bonding the foamable soft polymeric film to the substrate; e foaming the foamable soft polymeric film, wherein a first relief is provided on the side of the substrate provided with the foamed soft polymeric film; e Impression of a second relief on the side of the substrate provided with the foamed soft polymeric film. A method according to claim 1, wherein the foamable soft polymeric film consists of soft PVC. A method according to any one of the preceding claims, wherein the foam inhibitor is applied, for example printed, on both sides of the foamable soft polymeric film. A method according to any one of the preceding claims, wherein the application of the foam inhibitor is by digital printing, rotogravure printing or offset printing A method according to any one of the preceding claims, wherein the substrate comprises at least one hard or semi-hard polymer layer. A method according to any one of the preceding claims, wherein the substrate is formed from PVC. A method according to any one of the preceding claims, wherein the substrate is obtained by extruding polymeric material into a planar layer, fusing polymeric material particles into a planar layer or calendering polymeric material into a planar layer. A method according to any one of the preceding claims, wherein between the step of bonding the foamable soft polymeric film to the substrate and foaming the foamable soft polymeric film, a decorative layer is applied to the foamable soft polymeric film, wherein the decorative layer has a decorative image. A method according to claim 8, wherein the decorative layer is printed on the foamable soft polymeric film, preferably by digital printing, rotogravure printing or offset printing. A method according to claim 8, wherein the decorative layer is applied by bonding a printed film to the foamable soft polymeric film. A method according to any one of claims 8 to 10, wherein after application of the decorative layer, a transparent wear layer is applied. A method according to claim 11, wherein a transparent wear layer is bonded to the side of the printed film that will not contact the foamable soft polymeric film before the decorative layer is applied to the foamable soft polymeric film. A method according to any one of claims 8 to 12, wherein the decorative image and the first relief are in register. A method according to any one of claims 8 to 13, wherein the decorative image and the second relief are in register. A method according to any one of claims 8 to 14, wherein the decorative image represents rectangular elements, the foam inhibitor is applied at least, for example printed, along at least part of the perimeters of the rectangular elements. A method according to any one of the preceding claims, wherein the foamable soft polymeric film is foamed by thermal energy treatment. A method according to claim 16, wherein the foamable soft polymeric film comprises Azodicarbonamide (ADCA) as foam-forming component A method according to claim 16 or 17, wherein the foam inhibitor comprises one or more components selected from the group consisting of thioureas, e.g. thiourea, and triazoles, e.g. benzotriazole. A method according to any one of the preceding claims, wherein after pressing the second relief, a layer of lacquer is applied to the surface provided with the second relief. 20.- Method for manufacturing a layered wall or floor covering, comprising the steps of e Locally applying, for example printing, a foamable polymeric film with a foam inhibitor on at least one side; e Incorporation of the foamable polymeric film as a layer in the layered structure; e Foaming the foamable polymer film. The method of claim 20, wherein the foamable polymeric film is topically applied, e.g. printed, on both sides with foam inhibitor. Method according to claim 20 or 21, wherein the foamable polymeric film is a foamable soft PVC film. 23.- The use of a foam-inhibitor, for example printed, foamable polymer film applied locally on one or both sides, in a process for the manufacture of wall or floor coverings.