Mechanically embossed floor coverings

Abstract

Embossed floor coverings (200) are provided comprising: a substrate (202) comprising polyvinylchloride, polyurethane, acrylic, melamine, and / or polyolefin; a decorative layer (203) applied to the substrate (202); a wear layer (201) applied to the decorative layer (203), and an additional layer (204) on top of the wear layer (201). A texture is mechanically embossed into the wear layer (201) or into the additional layer (204). When the texture is embossed into the additional layer (204), indentations (205) of the texture penetrate into the wear layer (201). The wear layer (201) is prepared from a UV radiation-curable coating composition comprising: a reactive diluent comprising 2 to 6 (meth)acrylate functional groups, present in the curable coating composition in an amount of 10 to 40 percent by weight; and a free radical-polymerizable compound, present in the curable coating composition in an amount of 20 to 70 percent by weight. The free radical-polymerizable compound comprises 2 to 6 (meth)acrylate functional groups and an aliphatic polyester- or polyurethane-functional group.

Description

MECHANICALLY EMBOSSED FLOOR COVERINGSFIELD OF THE DISCLOSURE

[0001] The present disclosure relates to multi-layer, embossed floor coverings and methods of preparing them.BACKGROUND OF THE DISCLOSURE

[0002] Conventional floor coverings are typically multi-layer composites that include one or more wear layers combined with a substrate and resin to form a flooring sheet, plank or tile. The substrate usually comprises a continuous polymeric material, or a felted or matted fibrous material of overlapping, intertwined filaments or fibers. A wear layer may be defined as any layer that improves the wear properties of the floor covering, such as improved gouge and tear resistance, improved stain resistance, or improved scratch and abrasion resistance, compared to the same floor covering without such a wear layer.

[0003] Wear layers are often formed from plastisols; i. e., colloidal dispersions of polymeric particles, usually polyvinyl chloride (PVC), in a liquid plasticizer. When heated to around 180°C (356°F), the plastic particles absorb the plasticizer, causing them to swell and fuse together, forming a viscous gel. Once this is cooled to below 60°C (140°F) it becomes a flexible, permanently plasticized solid product. This solid plastisol may be mechanically embossed or treated with a blowing or foaming inhibitor for chemically embossing the surface.

[0004] A topcoat has at least a portion forming the exposed (outermost) surface of the floor covering. A high-performance topcoat is generally less than about 3 mils thick, formed from a radiation-cured, e.g. ultraviolet (UV) or electron beam (EB), composition. It is difficult to achieve thicker layers when using radiation-cured compositions, and mechanical embossing of a deep texture is challenging. Mechanical embossing is a faster, cost-effective alternative to chemical embossing.

[0005] It would be desirable to provide an embossed floor covering that demonstrates abrasion and cracking resistance while allowing for mechanical embossing.SUMMARY OF THE DISCLOSURE

[0006] Embossed floor coverings are provided comprising: (a) a substrate comprising polyvinylchloride, polyurethane, acrylic, melamine, and / or polyolefin; (b) a decorative layer applied to the substrate; (c) a wear layer applied to the decorative layer, and (d) an additional layer on top of the wear layer (c). A texture is embossed into the wear layer or into the additional layer. When the texture is embossed into the additional layer, at least a portion of indentations of the texture penetrate into the wear layer (c).

[0007] The wear layer is prepared from a UV radiation-curable coating composition comprising: (1 ) a reactive diluent comprising 2 to 6, or 2 to 4, or 2 to 3 (meth)acrylate functional groups, present in the curable coating composition in an amount of at least 10 percent by weight, or at least 15 percent by weight, or at least 20 percent by weight, and most 40 percent by weight, or at most 30 percent by weight, or at most 25 percent by weight, based on the total weight of the curable coating composition; and (2) a free radical-polymerizable compound different from the reactive diluent (1 ), present in the curable coating composition in an amount of at least 20 percent by weight, or at least 30 percent by weight, or at least 35 percent by weight, or at least 40 percent by weight, and at most 70 percent by weight, or at most 60 percent by weight, or at most 50 percent by weight, based on the total weight of the curable coating composition. The free radical-polymerizable compound comprises: (i) 2 to 6, or 2 to 4, or 2 to 3 (meth)acrylate functional groups; and (ii) a polyester- or polyurethane-functional linking group; wherein the group (ii) is aliphatic.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] FIG. 1 illustrates a schematic cross-sectional view of an example of an embossed floor covering in accordance with the present disclosure.

[0009] FIG. 2 illustrates a schematic cross-sectional view of an example of a floor covering in accordance with the present disclosure, but no indentations from a mechanically embossed pattern are shown. Primer layers between the flooring substrate and the decorative layer and between the wear layer and additional layer are shown.

[0010] Note that the relative thicknesses of each layer shown in the Figures are not representative of actual relative thicknesses.DETAILED DESCRIPTION OF THE DISCLOSURE

[0011] Other than in any operating examples, or where otherwise indicated, all numbers expressing quantities of ingredients, reaction conditions and so forth used in the specification and claims are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending upon the desired properties to be obtained by the present disclosure. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

[0012] Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the disclosure are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements.

[0013] Also, it should be understood that any numerical range recited herein is intended to include all sub-ranges subsumed therein. For example, a range of “1 to 10” is intended to include all sub-ranges between (and including) the recited minimum value of 1 and the recited maximum value of 10, that is, having a minimum value equal to or greater than 1 and a maximum value of equal to or less than 10.

[0014] As used in this specification and the appended claims, the articles "a," "an," and "the" include plural referents unless expressly and unequivocally limited to one referent.

[0015] The various embodiments and examples of the present disclosure as presented herein are each understood to be non-limiting with respect to the scope of the disclosure.

[0016] As used in the following description and claims, the following terms have the meanings indicated below:

[0017] The terms "on", "appended to", "affixed to", "bonded to", "adhered to", or terms of like import means that the designated item, e.g., a coating, component, or layer, is either directly connected to (in contact with) the object surface, or indirectly connected to the object surface, e.g., through one or more other coatings, components, or layers.

[0018] FIG. 1 illustrates a schematic cross-sectional view of an example of an embossed floor covering 200 in accordance with the present disclosure, wherein at least a portion of indentations 205 of the texture penetrate into the wear layer 201 .

[0019] The embossed floor coverings 200 of the present disclosure comprise (a) a substrate 202. Materials suitable for use as substrates typically include polymers, metals, wood, composites, veneers and laminates. The substrate 202 often comprises polyvinylchloride, polyurethane, acrylic, melamine, and / or polyolefin. Note that the phrase “and / or” when used in a list is meant to encompass alternative examples including each individual component in the list as well as any combination of components. For example, the list “A, B, and / or C” is meant to encompass seven separate examples that include A, or B, or C, or A + B, or A + C, or B + C, or A + B + C.

[0020] The substrate 202 is typically in the form of a flat sheet that may be rolled, a plank, or tile, having two opposing surfaces. Thicknesses may vary depending on the type of flooring being prepared.

[0021] The embossed floor coverings 200 of the present disclosure further comprise (b) a decorative layer 203 applied to the substrate 202. The decorative layer 203 may be printed or transferred onto the surface of the substrate 202; alternatively, the decorative layer 203 comprises a film having a decorative pattern printed or transferred thereon, that is adhesively applied to the substrate 202 such as by using an adhesive as known in the art between the substrate 202 and the decorative layer 203. When the decorative layer 203 is printed onto the surface of the substrate 202, the floor covering 200 may further comprise a primer layer 207 (shown in FIG. 2) between the substrate 202 and the decorative layer 203, and the decorative layer 203 is printed onto the primer layer. Suitable primers include any of those known in the art.

[0022] The embossed floor coverings of the present disclosure further comprise (c) a wear layer 201 applied to the decorative layer 203. The wear layer 201 is prepared from a curable coating composition, which comprises a (1 ) a reactive diluent having multiple (meth)acrylate functional groups. The term “(meth)acrylate” as used herein refers to acrylate and / or methacrylate functional groups. The reactive diluent comprises at least 2, and at most 6, or at most 4, or at most 3 (meth)acrylate functional groups. For example, the reactive diluent may comprise 2 to 6, or 2 to 4, or 2 to 3 (meth)acrylate functional groups.

[0023] Examples of suitable reactive diluents include dipropylene glycol diacrylate, propoxylated neopentyl glycol diacrylate, trimethylolpropane triacrylate, a polyether triacrylate (for example, OTA-480, a triacrylated reactive diluent based on a glycerol derivative available from Allnex GMBH), ditrimethylolpropane triacrylate, pentaerythritol tetraacrylate, 2-ethylhexyl acrylate, cyclic trimethylolpropane formal acrylate, 1 ,6-hexanediol diacrylate, tripropylene glycol diacrylate and / or dipentaerythritol pentaacrylate.

[0024] The reactive diluent is typically present in the curable coating composition in an amount of at least 10 percent by weight, or at least 15 percent by weight, or at least 20 percent by weight, and at most 40 percent by weight, or at most 30 percent by weight, or at most 25 percent by weight, based on the total weight of the curable coating composition. For example, the reactive diluent may be present in the curable coating composition in an amount of 10 to 40 percent by weight, or 10 to 30 percent by weight, or 10 to 25 percent by weight, or 15 to 40 percent by weight, or 15 to 30 percent by weight, or 15 to 25 percent by weight, or 20 to 40 percent by weight, or 20 to 30 percent by weight, or 20 to 25 percent by weight, based on the total weight of the curable coating composition.

[0025] The curable coating composition further comprises (2) a free radical- polymerizable compound different from the reactive diluent (1 ). The free radical- polymerizable compound comprises at least 2, and at most 6, or at most 4, or at most 3 (meth)acrylate functional groups. For example, the free radical-polymerizable compound may comprise 2 to 6, or 2 to 4, or 2 to 3 (meth)acrylate functional groups.

[0026] The free radical-polymerizable compound further comprises a polyester- or polyurethane-functional linking group, wherein the polyester- or polyurethane- functional group is aliphatic. Often, the polyester- or polyurethane-functional group contains no aromatic functional groups. Usually, the free radical-polymerizable compound contains no aromatic functional groups. The polyurethane-functional group may be prepared from aliphatic polyisocyanates and polyols such that the reaction product has 2 to 6 free isocyanate and / or hydroxyl groups available to react with functional groups such as acid, hydroxyl, amino, and epoxy functional groups in a (meth)acrylic compound. Likewise, the polyester-functional group may be prepared from aliphatic polyacids and polyols such that the reaction product has 2 to 6 free acid and / or hydroxyl groups available to react with functional groups such as acid, hydroxyl, amino, and epoxy functional groups in a (meth)acrylic compound. Note that the prefix “(meth)” is intended to refer to either an acrylic group or a methacrylic group. The polyester- or polyurethane-functional linking group is thus typically multi-valent, by which is meant it is at least divalent.

[0027] Examples of suitable aliphatic polyisocyanates used to prepare a polyurethane- functional group include 4,4'-methylene-bis(cyclohexyl isocyanate), isophorone diisocyanate, an isomeric mixture of 2,2,4- and 2,4,4-trimethyl hexamethylene diisocyanate, 1 ,6-hexamethylene diisocyanate, and biurets and trimers thereof. Examples of suitable aliphatic polyacids used to prepare a polyester-functional group include succinic acid, adipic acid, azelaic acid, sebacic acid, maleic acid, fumaric acid, and trimellitic acid. Besides the polycarboxylic acids mentioned above, functional equivalents of the acids such as anhydrides where they exist or lower alkyl esters of the acids such as the methyl esters may be used. Examples of suitable aliphatic polyols used to prepare a a polyester- or polyurethane-functional linking group include ethylene glycol, propylene glycol, butylene glycol, 1 ,6-hexylene glycol, neopentyl glycol, diethylene glycol, glycerol, trimethylol propane, and pentaerythritol. Mixtures of any of the above reactants may also be used.

[0028] The polyester- or polyurethane-functional reaction products having free reactive functional groups may be reacted with functional groups on a suitable (meth)acrylic compound, such as (meth)acrylic acid, hydroxyethyl methacrylate,hydroxypropyl methacrylate, amino functional (meth)acrylates, and the like, to form the free radical-polymerizable compound used in the UV radiation-curable coating composition.

[0029] Examples of commercially available, suitable free radical-polymerizable compounds include aliphatic polyester and polyurethane acrylates sold under the name LAROMER from BASF; EBECRYL 4201 and 8702, aliphatic urethane acrylates available from Allnex GMBH; and CN991 , a difunctional urethane acrylate available from Arkema, Inc.. Often the free radical-polymerizable compound comprises two (meth)acrylate functional groups and an aliphatic polyurethane-functional group. Combinations of free radical-polymerizable compounds may also be used.

[0030] The free radical-polymerizable compound is typically present in the curable coating composition in an amount of at least 20 percent by weight, or at least 30 percent by weight, or at least 35 percent by weight, or at least 40 percent by weight, and at most 70 percent by weight, or at most 60 percent by weight, or at most 50 percent by weight, based on the total weight of the curable coating composition. For example, the free radical-polymerizable compound may be present in the curable coating composition in an amount of 20 to 70 percent by weight, or 30 to 70 percent by weight, or 35 to 70 percent by weight, or 40 to 70 percent by weight, or 20 to 60 percent by weight, or 30 to 60 percent by weight, or 35 to 60 percent by weight, or 40 to 60 percent by weight, or 20 to 50 percent by weight, or 30 to 50 percent by weight, or 35 to 50 percent by weight, or 40 to 50 percent by weight, based on the total weight of the curable coating composition.

[0031] The curable coating composition may further comprise additives such as a photoinitiator, a defoamer, abrasion resistant particles such as aluminum oxide and silicon carbide, a filler, a dispersant, a flow / leveling agent, and / or an adhesion promoter, as known in the art. In certain examples, the curable coating composition is substantially free, essentially free, or completely free of a fluorine-functional (meth)acrylate compound. The terms “substantially free of [a given compound]” means that the composition contains less than 1000 parts per million (ppm) of the given compound; “essentially free of [a given compound]” means that the composition contains less than 100 ppm of the given compound; and “completely free of [a givencompound]” means that the composition contains less than 20 parts per billion (ppb) of the given compound. The weight is based on the total weight of the composition.

[0032] The curable coating compositions described herein are typically liquid at ambient temperature (for example, usually 20 to 25 °C, such as a typical room temperature, 72°F (22.2°C)). Any of the curable coating compositions described herein used to form the wear layer are typically 100% solids. “Solids”, or “nonvolatiles”, include any materials, whether solid or liquid at ambient temperature, that remain after subjecting a 1 -gram sample of the composition to 1 10°C for one hour.

[0033] The curable coating composition used to form the wear layer 201 is usually applied to the decorative layer 203 via roll coating, curtain coating, vacuum coating, or spray application. The thickness of the wear layer 201 is typically at least 100 microns, or at least 150 microns, and at most 250 microns, or at most 200 microns. For example, the thickness of the wear layer may range from 100 to 250 microns, or 100 to 200 microns, or 150 to 250 microns, or 150 to 200 microns. Multiple coats of the wear layer may be applied in order to obtain the desired film build (thickness).

[0034] The embossed floor coverings 200 of the present disclosure further comprise (d) an additional layer 204 on top of the wear layer 201. The additional layer may comprise a composition applied directly as a single layer to the wear layer 201 , or may comprise an intervening primer layer 209 (shown in FIG. 2) and one or more topcoat layers. The additional layer 204 is usually unpigmented (i. e., a clear coat), and at least a portion thereof is the outermost layer (topcoat) of the floor covering 200. Such layers contribute to scratch and stain resistance, and may be selected to provide any desired gloss level. The thickness of the additional layer 204 is typically 10 to 25 microns. Suitable compositions include any of those known in the art, such as those sold under the names Raycron and Claritage, available from PPG.

[0035] A texture may be embossed onto the floor covering 200 into the wear layer 201 before application of the additional layer 204, or the texture may be embossed into the additional layer. Embossing is more often performed on the wear layer 201 , prior to application of the additional layer 204, and is typically done mechanically via a roll embosser. Digital embossing via a digital embosser is also possible. When the additional layer 204 is subsequently applied, it conforms to the indentations 205 of thetexture. In certain examples, when the texture is embossed into the additional layer 204, at least a portion of indentations 205 of the texture penetrate into the wear layer 201 ; i. e., through the additional layer 204. This property is afforded by the composition of the curable coating composition used to form the wear layer.

[0036] The embossed floor coverings 200 described herein can be prepared by a method comprising:(a) applying any of the curable coating compositions described above to a decorative layer 203 on a substrate 202, either directly or on top of an intervening primer layer 207;(b) at least partially curing the curable coating composition to form a wear layer 201 by exposing the curable coating composition to UV radiation;(c) embossing a texture onto the wear layer 201 ; and(d) applying an additional layer 204 on top of the wear layer 201 to form an embossed floor covering.

[0037] The curable coating composition may be applied to the decorative layer 203 by conventional means such as rolling, spraying, vacuum coating or curtain coating. After application, the curable coating composition is at least partially cured to form a wear layer 201 by exposing the curable coating composition to ultraviolet (UV) or electron beam (EB) radiation. As noted above, multiple coats of the curable coating composition the forms the wear layer may be applied in order to obtain the desired film build (thickness).

[0038] The term “cure”, “cured” or similar terms, as used in connection with a cured or curable composition, e.g., a “cured composition” of some specific description, means that at least a portion of any polymerizable and / or crosslinkable components that form the curable composition is polymerized and / or crosslinked. Additionally, curing of a composition refers to subjecting said composition to curing conditions such as those listed above, leading to the reaction of the reactive functional groups of the composition. The term “at least partially cured” means subjecting the composition to curing conditions, wherein reaction of at least a portion of the reactive groups of the composition occurs. The composition can also be subjected to curing conditions suchthat a substantially complete cure is attained and wherein further curing results in no significant further improvement in physical properties, such as hardness.

[0039] In step (c), a texture is embossed onto the wear layer 201 . As noted above, embossing is often performed mechanically via a roll embosser. Again, when the additional layer 204 is subsequently applied, it conforms to the indentations 205 of the texture. The embossing step may alternatively be done after application of the additional layer 204. In this case, at least a portion of indentations 205 of the texture penetrate into the wear layer 201 .

[0040] After exposing the curable coating composition to radiation, an additional layer 204 is applied on top of the wear layer 201 using conventional means, to form a floor covering 200. Again, the additional layer 204 may comprise a composition applied directly as a single layer to the wear layer 201 , or may comprise an intervening primer layer 209 and a topcoat layer. If a primer layer is used, it may be at least partially cured, usually by UV radiation, prior to application of the additional layer. A final curing step is usually performed after application of the additional layer to cure all layers.

[0041] It is possible, but not necessary, to heat the substrate 202 prior to application of the wear layer, and / or to heat the wear layer 201 prior to embossing to enhance the embossing step. It is also possible to heat a composition prior to application, or to heat the embossing roller.

[0042] The present disclosure is also directed to the following aspects:1 . An embossed floor covering comprising:(a) a substrate comprising polyvinylchloride, polyurethane, acrylic, melamine, and / or polyolefin;(b) a decorative layer applied to the substrate;(c) a wear layer applied to the decorative layer, wherein the wear layer is prepared from a UV radiation-curable coating composition comprising:(1 ) a reactive diluent comprising 2 to 6 (meth)acrylate functional groups, present in the curable coating composition in an amount of at least 10 percent by weight and at most 40 percent by weight, based on the total weight of the curable coating composition; and(2) a free radical-polymerizable compound different from the reactive diluent (1 ), present in the curable coating composition in an amount of at least 20 percent by weight, and at most 70 percent by weight, based on the total weight of the curable coating composition; wherein the free radical-polymerizable compound comprises:(i) 2 to 6 (meth)acrylate functional groups; and(ii) a polyester- or polyurethane-functional linking group; wherein the linking group (ii) is aliphatic; and(d) an additional layer on top of the wear layer (c), wherein a texture is embossed into the wear layer or into the additional layer; and wherein when the texture is embossed into the additional layer, at least a portion of indentations of the texture penetrate into the wear layer (c).2. The floor covering according to aspect 1 , wherein the reactive diluent comprises 2 to 4 (meth)acrylate functional groups.3. The floor covering according to any preceding aspect, wherein the reactive diluent comprises 2 to 3 (meth)acrylate functional groups.4. The floor covering according to any preceding aspect, wherein the reactive diluent is present in the curable coating composition in an amount of at least at least 15 percent by weight, based on the total weight of the curable coating composition.5. The floor covering according to any preceding aspect, wherein the reactive diluent is present in the curable coating composition in an amount of at least at least 20 percent by weight, based on the total weight of the curable coating composition.6. The floor covering according to any preceding aspect, wherein the reactive diluent is present in the curable coating composition in an amount of at most 30 percent by weight, based on the total weight of the curable coating composition.7. The floor covering according to any preceding aspect, wherein the reactive diluent is present in the curable coating composition in an amount of at most 25 percent by weight, based on the total weight of the curable coating composition.8. The floor covering according to any preceding aspect, wherein the free radical-polymerizable compound is present in the curable coating composition in an amount of at least 30 percent by weight, based on the total weight of the curable coating composition.9. The floor covering according to any preceding aspect, wherein the free radical-polymerizable compound is present in the curable coating composition in an amount of at least at least 35 percent by weight, based on the total weight of the curable coating composition.10. The floor covering according to any preceding aspect, wherein the free radical-polymerizable compound is present in the curable coating composition in an amount of at least at least 40 percent by weight, based on the total weight of the curable coating composition.11 . The floor covering according to any preceding aspect, wherein the free radical-polymerizable compound is present in the curable coating composition in an amount of at most 60 percent by weight, based on the total weight of the curable coating composition.12. The floor covering according to any preceding aspect, wherein the free radical-polymerizable compound is present in the curable coating composition in an amount of at most 55 percent by weight, based on the total weight of the curable coating composition.13. The floor covering according to any preceding aspect, wherein the free radical-polymerizable compound is present in the curable coating composition in an amount of at most 50 percent by weight, based on the total weight of the curable coating composition.14. The floor covering according to any preceding aspect, wherein the free radical-polymerizable compound comprises 2 to 4 (meth)acrylate functional groups.15. The floor covering according to any preceding aspect, wherein the free radical-polymerizable compound comprises 2 to 3 (meth)acrylate functional groups.16. The floor covering according to any preceding aspect, wherein the substrate (a) comprises polyvinylchloride.17. The floor covering according to any preceding aspect, wherein the decorative layer (b) comprises a film that is adhesively applied to the substrate (a).18. The floor covering according to any preceding aspect, further comprising a primer layer between the substrate (a) and the decorative layer (b), wherein the decorative layer is printed onto the primer layer.19. The floor covering according to any of the preceding aspects, wherein the texture is embossed into the additional layer.20. The floor covering according to any of the preceding aspects, wherein the free radical-polymerizable compound comprises two (meth)acrylate functional groups and an aliphatic polyurethane-functional group.21 . The floor covering according to any of the preceding aspects, wherein the reactive diluent (1) comprises dipropylene glycol diacrylate, propoxylated neopentyl glycol diacrylate, trimethylolpropane triacrylate, a polyether triacrylate,ditrimethylolpropane triacrylate, pentaerythritol tetraacrylate, 2-ethylhexyl acrylate, cyclic trimethylolpropane formal acrylate, 1 ,6 hexanediol diacrylate, tripropylene glycol diacrylate and / or dipentaerythritol pentaacrylate.22. The floor covering according to any of the preceding aspects, wherein the UV radiation-curable coating composition further comprises a photoinitiator, a defoamer, abrasion resistant particles, a filler, a dispersant, a flow / leveling agent, and / or an adhesion promoter.23. The floor covering according to any of the preceding aspects, further comprising a primer layer between the wear layer (c) and the additional layer (d).24. The floor covering according to any of the preceding aspects, wherein the texture is embossed into the wear layer.25. The floor covering according to any of the preceding aspects, wherein the thickness of the wear layer is at least 100 microns, or at least 150 microns, and at most 250 microns, or at most 200 microns.26. The floor covering according to any of the preceding aspects, wherein the thickness of the wear layer is at least 150 microns.27. The floor covering according to any of the preceding aspects, wherein the thickness of the wear layer is most 200 microns.28. The floor covering according to any of the preceding aspects, wherein the thickness of the additional layer ranges from 10 to 25 microns.29. The floor covering according to any of the preceding aspects, wherein the UV radiation-curable coating composition is substantially free, essentially free, or completely free of fluorine-functional (meth)acrylate compounds.

[0043] The following working Examples are intended to further describe and demonstrate the embossed floor coverings and methods described herein. It is understood that the disclosure of this specification is not necessarily limited to the examples described in this section. Unless otherwise indicated, all parts are by weight.EXAMPLES

[0044] For each Example, UV radiation-curable film-forming compositions were prepared for use as a wear layer by adding the appropriate amount of each resin and reactive diluent as shown in Tables 1 and 2 into a mixer. The remaining components were added in order and under agitation. The compositions were mixed until fully blended to a uniform consistency.Table 11 Tri-functional acid acrylate ester available from Arkema, Inc.2 Aliphatic urethane hexaacrylate available from Allnex3 Aliphatic urethane acrylate available from Allnex4 Hexafunctional aliphatic urethane acrylate oligomer available from Allnex5 Aliphatic urethane acrylate available from Allnex6 Defoamer available from Evonik Industries7 Silicon dioxide available from Evonik IndustriesTable 21 Acid Based Adhesion Promoter from Arkema, Inc.2 Polyester urethane diacrylate available from Arkema, Inc.3 Polyester acrylate from BASF4 Aliphatic urethane acrylate available from Allnex

[0045] The UV radiation-curable film-forming compositions of Examples 1 to 9 were applied to preprinted Luxury Vinyl Tile (LVT) substrates according to the following process; however, the substrate tiles of Examples 7 to 9 were not embossed. The LVT substrates were previously coated with a UV-curable white primer (available from Klumpp Coatings) and digital print design.1 . Wear layer compositions were applied using a roll coat application in two stages, to obtain the desired film build.2. Each stage was partially cured to improve adhesion of subsequently applied layers. The first stage had approximately 3.5 mils of wear layer applied and then partially cured.The second stage had approximately 2.5 mils of wear layer applied and then partially cured.3. Primer was applied over the partially cured wear layer using a roll coat application to the desired film thickness of 0.3 mils.4. Primer was partially cured.5. Topcoat (available from PPG as R2646Z74) was applied over the partially cured primer using a roll coat application to the desired film thickness of 0.20 mils.6. Topcoat was fully cured.7. Samples were embossed mechanically using a wood grain pattern.Test Methods

[0046] After preparation and embossing of the tiles of Examples 1 to 6, the wear layers were evaluated for ease of embossing and wear resistance.

[0047] Ease of embossing: In order to determine how well a sample could be embossed, the embossing depth and cracking were evaluated. The embossing depth was determined by measuring the depth using a depth gauge, where the tip of the gauge was placed in the embossing well and the base of the gauge sat on the peaks of the embossed areas. In addition, the embossed sample was visually evaluated for cracks. To identify the cracks more readily, green food coloring was wiped onto the surface of the embossed panel and then wiped off. The green food coloring will easily wipe off the cured UV topcoat and stain the digital print that is exposed underneath the cracks. The samples were evaluated with and without the aid of a microscope to help determine the degree of cracking. The following rating scale was used to evaluate cracks:0 - No Cracks1 - Microcracks that are not visible to the eye but seen under the microscope2 - Fragmented cracks that cannot be easily seen with the unaided eye3 - Moderate cracking (mostly along the embossed area)4 - Severe cracking5 - Significant cracking over the entire panel, where the cracks run both parallel and perpendicular to the embossing.

[0048] Wear Resistance (Taber Resistance): Samples of Examples 1 to 6 were evaluated for wear resistance by determining the number of Taber cycles needed to reach the initial wear point of coating. The initial wear point is where there is clear wear-through of the digital print layer and the sub layer becomes exposed in six out of the eight octants. The initial wear point occurs when there is at least 1 .00mm2of wear- through in 6 of the 8 octants. When evaluating Taber resistance, the wear-through is defined as the wear where the digital print is removed and the white primer shows through. Taber resistance was run according to BS EN 13329:2016+A2:2021 Test Method using Taber S-42 sandpaper strips as the abrasive material. The number of cycles of Taber resistance needed to obtain a passing rating is determined by the abrasion class that is required. An abrasion class of AC5 is >6000 cycles for initial wear-through point; an abrasion class of AC4 is >4000 cycles for initial wear-through point.

[0049] For Examples 7 to 9, Taber resistance was run according to NF EN1651 1 +A1 Test Method using Taber Sand. The number of cycles of Taber resistance needed to obtain a passing rating is determined by the abrasion class that is required. An abrasion class of 32 is >=3000 cycles for initial wear-through point, 33 is >=5000 cycles for initial wear-through point, 34 is >=7000 cycles for initial wear-through point.

[0050] Testing results are shown in Tables 3 and 4.Table 3Table 4

[0051] The initial wear-through point is influenced significantly by the film thickness of the wear layer because the initial wear-through point requires wearing through all applied coatings down through the digital print; thus, the greater the film thickness, the more cycles needed to reach the initial wear through point. The compositions used in the embossed floor coverings of the present disclosure provide significant embossing depths with minimal cracking.

[0052] It is understood that the disclosure of the specification is not necessarily limited to the examples described. Components that are mentioned elsewhere in the specification as suitable alternative materials for use, but which are not demonstrated in the working Examples, are expected to provide results comparable to their demonstrated counterparts.

[0053] Whereas particular embodiments of this disclosure have been described above for purposes of illustration, it will be evident to those skilled in the art that numerous variations of the details of the present disclosure may be made without departing from the scope of the disclosure as defined in the appended claims.

Claims

WHAT IS CLAIMED IS:1 . An embossed floor covering comprising:(a) a substrate comprising polyvinylchloride, polyurethane, acrylic, melamine, and / or polyolefin;(b) a decorative layer applied to the substrate;(c) a wear layer applied to the decorative layer, wherein the wear layer is prepared from a UV radiation-curable coating composition comprising:(1 ) a reactive diluent comprising 2 to 6 (meth)acrylate functional groups, present in the curable coating composition in an amount of at least 10 percent by weight and at most 40 percent by weight, based on the total weight of the curable coating composition; and(2) a free radical-polymerizable compound different from the reactive diluent (1 ), present in the curable coating composition in an amount of at least 20 percent by weight and at most 70 percent by weight, based on the total weight of the curable coating composition; wherein the free radical-polymerizable compound comprises:(i) 2 to 6 (meth)acrylate functional groups; and(ii) a polyester- or polyurethane-functional linking group; wherein the linking group (ii) is aliphatic; and(d) an additional layer on top of the wear layer (c), wherein a texture is embossed into the wear layer or into the additional layer; and wherein when the texture is embossed into the additional layer, at least a portion of indentations of the texture penetrate into the wear layer (c).

2. The floor covering according to claim 1 , wherein the substrate (a) comprises polyvinylchloride.

3. The floor covering according to claim 1 or 2, wherein the decorative layer (b) comprises a film that is adhesively applied to the substrate (a).

4. The floor covering according to claim 1 or 2, further comprising a primer layer between the substrate (a) and the decorative layer (b), wherein the decorative layer is printed onto the primer layer.

5. The floor covering according to any of the preceding claims, wherein the texture is embossed into the additional layer.

6. The floor covering according to any of the preceding claims, wherein the free radical-polymerizable compound comprises two (meth)acrylate functional groups and an aliphatic polyurethane-functional group.

7. The floor covering according to any of the preceding claims, wherein the reactive diluent (1 ) comprises dipropylene glycol diacrylate, propoxylated neopentyl glycol diacrylate, trimethylolpropane triacrylate, a polyether triacrylate, ditrimethylolpropane triacrylate, pentaerythritol tetraacrylate, 2-ethylhexyl acrylate, cyclic trimethylolpropane formal acrylate, 1 ,6-hexanediol diacrylate, tripropylene glycol diacrylate and / or dipentaerythritol pentaacrylate.

8. The floor covering according to any of the preceding claims, wherein the UV radiation-curable coating composition further comprises a photoinitiator, a defoamer, abrasion resistant particles, a filler, a dispersant, a flow / leveling agent, and / or an adhesion promoter.

9. The floor covering according to any of the preceding claims, further comprising a primer layer between the wear layer (c) and the additional layer (d).

10. The floor covering according to any of the preceding claims, wherein the texture is embossed into the wear layer.1 1 . The floor covering according to any of the preceding claims, wherein the thickness of the wear layer is at least 100 microns and at most 250 microns.

12. The floor covering according to any of the preceding claims, wherein the thickness of the additional layer ranges from 10 to 25 microns.

13. The floor covering according to any of the preceding claims, wherein the UV radiation-curable coating composition is substantially free, essentially free, or completely free of fluorine-functional (meth)acrylate compounds.

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