WO2017009066A1

WO2017009066A1 - Scuff resistant decorative surface coverings

Info

Publication number: WO2017009066A1
Application number: PCT/EP2016/065461
Authority: WO
Inventors: Richard Peres; Dung Dao Viet; Christelle HENROTIN; Philippe CASEAU; Jean- Luc STIERNET
Original assignee: Tarkett Gdl
Priority date: 2015-07-16
Filing date: 2016-07-01
Publication date: 2017-01-19
Also published as: CA2987804A1

Abstract

The present invention is related to decorative surface coverings, in particular floor or wall coverings, comprising one or more polymer layer(s) and a cross-linked polyurethane top-layer, combining excellent anti-slip properties and scuff resistance. The invention is further related to a method for the preparation of said surface coverings.

Description

SCUFF RESISTANT DECORATIVE SURFACE COVERINGS

Field of the Invention

[0001] The present invention is related to decorative floor and wall coverings comprising a polyurethane top coat showing improved anti-slip properties and scuff-resistance. The invention is further related to a method for the production of said surface coverings.

State of the Art

[0002] Surface covering materials, and especially surface covering materials adapted for use as floor and wall coverings, must frequently possess a wide range of sometimes contradictory properties and characteristics. For example, there has been an increasing demand for floor covering materials having improved scuff resistance. Furthermore, it is highly desirable for such floor covering materials to possess satisfactory anti-slip properties.

[0003] The term "scuff resistance" is the ability of the wear surface to resist plastic flow when subjected to the force and frictional heat caused by the dragging of, for example, rubber or plastic soled shoes.

[0004] The term "slip-resistance" is the ability of the wear surface to allow safe walking of a test person, the slope of said surface being increased from the initial horizontal state to the acceptance angle where the limit of safe walking is reached and the test person slips.

[0005] The current state of the art of floor covering materials presents either satisfactory anti slip properties or scuff resistance and relies primarily on the use of polyurethane coating compositions as topcoat.

[0006] The use of radiation curable polyurethane compositions as top layer for decorative surface coverings are for example disclosed in EP 0210620 (B1 ), US 4,100,318, US 4,393,187, US 4,598,009, US 5,543,232, US 6,586,108, US 2013/0230729, DE 4421559, FR 2,379,323, KR 20010016758, JPH 06279566, CN 103242742 and WO 03/022552.

[0007] US 5,458,953 discloses a resilient surface covering, said resilient surface covering comprising (a) a resilient support surface and (b) a resilient wear surface adhered to said resilient support surface, said resilient wear surface comprising an underlying wear layer base coat and an overlying wear layer top coat adhered to said wear layer base coat, said wear layer top coat comprising a hard, thermoset, polymeric UV-curable blend of acrylic or acrylate monomers. The chemically cross-linked urethane or urethane acrylate wear surfaces results in improved marring, scuffing and/or soiling resistance. [0008] US 5,401 ,560 relates to non-slip materials which are provided by coating a polymer sheet backing, preferably a polyvinyl chloride sheet, with mineral particles adhered to the backing by a radiation curable polyurethane binder material. The radiation cured polyurethane binder material is electron beam cured. A variety of mineral particles may be employed which will provide adequate frictional contact in use to prevent, or aid in the prevention of slippage. Examples of suitable mineral particles are aluminum oxide and silicon carbide fumed silica and silica gel.

[0009] The preferred resin system is a combination of resin components, made from commercially available resins, with diluents and other components. The resin system(s) preferably comprise a blend of two or more grades of urethane oligomers. In addition, one or more surfactants, preferably containing fluorocarbon material, may be added as wetting agents.

[0010] KR 100292584 discloses a process of preparing a decorative floor covering having excellent stain resistance whereby, the floor covering does not become dirty by a contaminant and is easy for cleaning. This superior stain resistant decorative floor covering comprises a surface layer comprising several layers wherein the upper most layer of the surface layer is a surface-treated layer which is prepared by air knife coating of a composition containing 40 parts by weight of urethaneacrylate oligomer, 7 to 1 1 parts by weight of monomer 2-hydroxypropyl acrylate, 43 to 34 parts by weight of 1 ,6-hexanedioldiacrylate, 0 to 5 parts by weight of trimethylolpropaneethoxytriacrylate, 4 parts by weight of acetophenone photoinitiator, 1 part by weight of silicone and 5 parts by weight of silica as a matting agent and then curing.

[0011] While polyurethane surface coatings have achieved a significant degree of success in the flooring industry, there has been a general recognition that several disadvantages are associated with such surface coverings. For example, it is generally accepted that polyurethane coatings can be formulated to possess a high degree of anti-scuff properties. However, it is equally well established that scuff-resistant polyurethane coatings generally exhibit poor anti-slip. Nevertheless, both of these properties are extremely important for the production of a commercially successful surface covering, especially a surface covering which is exposed to the conditions encountered by flooring materials.

[0012] It is nevertheless possible to formulate polyurethane coating compositions that have improved anti-slip properties. Unfortunately, such improvements can generally only be obtained at the expense of scuff resistance. Therefore polyurethane coating compositions which are formulated to exhibit improved anti-slip properties will also generally exhibit unsatisfactory scuff resistance. Aims of the invention.

[0013] The present invention aims to provide a decorative surface covering, in particular floor or wall covering, comprising one or more layer(s) comprising one or more polyolefin(s) and/or polyvinyl chloride and a radiation cured top-layer with good adhesion to the top of the surface layer of the one or more layer(s), said radiation cured top-layer combining excellent scuff-resistance and anti-slip properties.

[0014] A further aim of the present invention is to provide a process for the production of said surface coverings. Summary of the Invention.

[0015] The present invention discloses a printed decorative surface covering comprising one or more polymer layer(s) and a polyurethane top-layer completely covering the top surface of the one or more polymer layers, said top-layer comprising:

40 to 75% by weight of cross-linked polyurethane, said polyurethane comprising an anionic or cationic salt group;

0.5 to 25% by weight of one or more types of micro-scale particle(s) and/or one or more types of nano-scale particle(s);

0.1 to 20% by weight of one or more silicone(s);

wherein

- the polyurethane top-layer is a single layer comprising:

- 0.1 to 20% by weight of one or more silicone(s); or

- the polyurethane top-layer comprises a first layer b.1 .) completely covering the top-surface of the one or more polymer layer(s) and a patterned second layer b.2.) atop of the first layer b.1 .), wherein said first layer b.1 .) comprises:

0.1 to 20% by weight of one or more silicone(s); and

wherein said second layer b.2.) comprises:

60 to 90% by weight of cross-linked polyurethane, said polyurethane comprising an anionic or cationic salt group; and

- 0.5 to 25% by weight of one or more types of micro-scale particle(s) and/or one or more types of nano-scale particle(s); or - the polyurethane top-layer comprises a patterned first layer b.1 .) partially covering the top- surface of the one or more polymer layer(s) and a second layer b.2.) atop of that part of the top-surface of the one or more polymer layer(s) that does not comprise the first layer b.1 .) wherein said first layer b.1 .) comprises:

- 40 to 75% by weight of cross-linked polyurethane, said polyurethane comprising an anionic or cationic salt group;

0.1 to 20% by weight of one or more silicone(s); and

wherein said second layer b.2.) comprises:

0.5 to 25% by weight of one or more types of micro-scale particle(s) and/or one or more types of nano-scale particle(s).

[0016] Preferred embodiments of the present invention disclose one or more of the following features:

- the polyurethane top-layer comprises from 1 to 20% by weight of one or more

thermoplastic homo- or copolymer(s) comprising one or more vinyl alkanoate(s) selected from the group consisting of vinyl acetate, vinyl propionate and vinyl butyrate and/or one or more vinyl acetal(s) selected from the group consisting of vinyl formal, vinyl acetoacetal, vinyl propyral and vinyl butyral, and/or vinyl alcohol;

- the types of one or more micro- and/or nano-scale particles are selected from the group consisting of glass particles, plastic particles, metal oxide particles, metalloid oxide particles and metal salt particles and mixings thereof;

the average particle size of the micro- and or nano-scale particles is comprised between 0.02 and 200%, preferably between 0.04 and 170%, more preferably between 0.06 and 1 30% and most preferably between 0.08 and 100% of the cross-linked polyurethane layer thickness;

the one or more silicone(s) comprise one or more polyorganosiloxanes;

the one or more polymer layer(s) comprise(s) one or more polymers selected from the group consisting of polyvinyl halides, polyolefins and block copolymers comprising polymer blocks of one or more vinyl aromatic monomer(s) and polymer blocks of one or more alkylene(s);

the decorative surface covering comprises an embossed structure;

the average particle size of the micro- and or nano-scale particles is comprised between 0.01 and 200%, preferably between 0.05 and 150%, more preferably between 0.1 and 100% and most preferably between 0.2 and 50% of the embossing depth. [0017] The present invention further discloses a process for the preparation of the decorative surface covering, comprising the steps of providing one or more polymer layer(s), and

applying an aqueous polyurethane dispersion on the surface of the one or more polymer layer(s),

evaporating water from the aqueous dispersion to form an uncured top-layer comprising an ethylenically unsaturated polyurethane,

irradiating the ethylenically unsaturated polyurethane to form a cross-linked polyurethane top-layer,

or

patterned applying a first and a second aqueous polyurethane dispersion on the surface of the one or more polymer layer(s),

evaporating water from the aqueous dispersions to form an uncured top-layer comprising an ethylenically unsaturated polyurethane,

- irradiating the ethylenically unsaturated polyurethane to form a cross-linked polyurethane top-layer, comprising patterned cross-linked first layer b.1 ) and patterned cross-linked second layer b.2.);

or

applying a first aqueous polyurethane dispersion on the surface of the one or more polymer layer(s),

evaporating water from the first aqueous dispersion to form an uncured first layer comprising an ethylenically unsaturated polyurethane,

optionally irradiating the ethylenically unsaturated polyurethane to form the first layer b.1 .).

- applying a second aqueous polyurethane dispersion on the surface of the first layer b.1 ) according to a pattern of covered and uncovered zones,

evaporating water from the second aqueous dispersion to form an uncured patterned second layer comprising an ethylenically unsaturated polyurethane,

irradiating the ethylenically unsaturated polyurethane to form a cross-linked polyurethane top-layer, comprising the crosslinked first layer b.1 ) with the cross-linked patterned second layer b.2.) atop.

[0018] Preferred embodiments of the process for the preparation of said decorative surface covering disclose one or more of the following features:

- the aqueous radiation curable polyurethane dispersion comprises 20 to 80% by weight, preferably 25 to 60% by weight of radiation curable compounds and from 0.5 to 10% by weight, preferably from 2 to 8% by weight of at least one photoinitiator, relative to the total weight of the dispersion;

the radiation curable compounds of the aqueous radiation curable polyurethane dispersion comprise at least 65% by weight, preferably at least 76% by weight of one or more ethylenically unsaturated polyurethane resin(s) and at most 35% by weight preferably at most 24% by weight of one or more reactive diluent(s);

- the aqueous radiation curable polyurethane dispersion comprises:

from 0.1 to 20% by weight of one or more micro-scale particle(s), nano-scale particle(s) or a mixture thereof and from 0.1 to 15% by weight of one or more silicone(s), for the formation of top-layer a);

from 0.1 to 15% by weight of one or more silicone(s) for the formation of first layer b.1 .);

from 0.1 to 20% by weight of one or more micro-scale particle(s) and/or nano- scale particle(s), for the formation of second layer b.2.);

- the aqueous dispersion is applied at a temperature comprised between 25°C and 60°C and preferably between 30°C and 50°C;

the top surface of the one or more polymer layer(s) is subjected to a plasma treatment, preferably a corona plasma treatment;

the one or more polymer layer(s) comprising the uncured layer are mechanically embossed;

mechanical embossing is performed at a surface temperature comprised between 100°C and 200°C;

irradiating the uncured layer is performed at a temperature comprised between 30°C and 70°C preferably between 30°C and 60°C.

Detailed Description of the Invention

[0019] The object of the present invention is to provide decorative floor and wall coverings comprising a polyurethane comprising top-layer combining excellent scuff- resistance and anti-slip properties. Said top-layer is obtained from radiation curing one or more radiation curable compositions, preferably one or more radiation curable aqueous polyurethane dispersion(s).

[0020] In one embodiment the decorative surface coverings of the present invention comprise a stack of layers, preferably comprising a backing layer, a decor layer, at least one wear layer all preferably comprising one or more olefin (co)polymers and/or one or more vinyl halide (co)polymers and a top-layer comprising a cross-linked polyurethane on the top-surface of the wear layer. [0021] The decorative surface coverings preferably comprise one or more layers decorated with a pattern and colors by any printing means. Prior to the printing process, the one or more layers are optionally provided with a primer.

[0022] Additional layers can be present. The additional layers can be used for a variety of purposes, such as for reinforcement.

[0023] In another embodiment the decorative surface coverings comprise one layer comprising one or more olefin (co)polymers and/or one or more vinyl halide (co)polymers and a cross-linked polyurethane comprising top-layer on the top-surface of said layer.

[0024] The one or more polyolefin (co)polymers comprise one or more homo and/or copolymers selected from the group consisting of an ethylene homopolymer, a propylene homopolymer, an ethylene copolymer comprising alpha-olefins, an olefin copolymer comprising vinyl carboxylate esters, an olefin copolymer comprising alkyl (meth)acrylates, a polyolefin elastomer and a polar group comprising polyolefin.

[0025] The one or more vinyl halide (co)polymers are selected from the group consisting of polyvinyl chloride homopolymers, and copolymers of vinyl chloride and one or more ethylenically unsaturated monomers selected from the group consisting of vinylidene chloride, (meth)acrylic acid esters, α,β-unsaturated dicarboxylic acid esters, vinyl alkanoates, and alkylenes.

[0026] The one or more layer(s) further may comprise one or more styrene/olefin based elastomers.

[0027] The one or more layer(s) further may comprise organic or inorganic fillers, lubricants and additives.

[0028] The polyurethane comprising top-layer on the top surface of the one or more layer(s) is obtained from radiation curable aqueous polyurethane dispersions after being subjected to actinic irradiation.

[0029] The radiation curable aqueous polyurethane dispersions of the present invention in generally are obtained from the reaction of:

a) at least one polyisocyanate,

b) at least one hydrophilic compound containing at least one reactive group capable to react with isocyanate groups and at least one group which is capable to render the polyurethane dispersible in aqueous medium either directly or after a reaction with a neutralizing agent to provide a salt,

c) at least one polymerizable ethylenically unsaturated compound containing at least one reactive group capable to react with isocyanate groups and

d) at least one compound which differs from compound (c) containing at least one reactive group capable to react with isocyanate groups. [0030] By polyisocyanate compound (a) is meant to designate organic compounds comprising at least two isocyanate groups. The polyisocyanate compound usually comprises not more than three isocyanate groups. The polyisocyanate compound (a) is most preferably a di-isocyanate. The polyisocyanate compound is generally selected from aliphatic, cycloaliphatic, aromatic and/or heterocyclic polyisocyanates or combinations thereof.

[0031] The hydrophilic compound (b) is generally a polyol or polyamine comprising a functional group that can exhibit an ionic or non-ionic hydrophilic nature. Preferably it is a polyol or polyamine containing one or more anionic salt groups, such as a carboxylate and sulfonate salt groups or acid groups which may be converted to an anionic salt group, such as carboxylic acid or sulfonic acid groups. A typical example is 2,2- dimethylolpropionic acid and 2,2-dimethylolbutanoic acid.

[0032] Alternatively a polyol containing one or more potentially cationic groups such as amine groups, which may be converted in ammonium salt groups such as for example N-methyldiethanolamine, can be used.

[0033] Polymerizable ethylenically unsaturated compound (c) in general have one or more reactive groups capable to react with isocyanate groups and at least one (meth)acrylated group.

[0034] Compounds (c) in general contain one or more unsaturated function such as acrylic or methacrylic group and essentially one nucleophilic function capable of reacting with isocyanate, such as a hydroxyl group. Preferred are (meth)acryloyl mono-hydroxy compounds, more particularly poly(meth)acryloyl mono-hydroxy compounds.

[0035] Compound (d), containing at least one reactive group capable to react with isocyanate groups, in general comprises monomeric mono- and/or polyols and/or mono- and/or polyamines.

[0036] Compound (d) furthermore comprises oligomeric and/or polymeric hydroxy-functional compounds. These oligomeric and/or polymeric hydroxy-functional compounds are, for example, polyesters, polyethers, polyether-esters, polycarbonates, polyether carbonate polyols and polycarbonate polyesters having a functionality of from 1.0 to 3.0.

[0037] Usually the dispersion requires the preliminary neutralization of the hydrophilic groups, provided by compound (b), into salts.

[0038] The aqueous dispersion preferably comprises reactive diluents containing at least one group which can undergo free radical polymerization. Typical examples of reactive diluents are 1 ,6-hexanediol diacrylate and tetraethylene glycol diacrylate.

[0039] The reactive diluents are employed to the extent of 0 to 50% by weight, preferably of 2 to 40% by weight, more preferably of 5 to 30% by weight, most preferably of 7 to 24% by weight relative to the total weight of the radiation curable compounds. [0040] The reactive diluents may be added before the dispersion is made or after, yet addition before is mostly preferred.

[0041 ] The aqueous radiation curable dispersion in general comprises from 20 to 80% by weight, preferably from 25 to 60% by weight of one or more radiation curable compounds said radiation curable compounds comprising at least 65% by weight, preferably at least 76% by weight of one or more ethylenically unsaturated polyurethane resin(s) and at most 35% by weight, preferably at most 24% by weight of one or more reactive diluent(s).

[0042] The aqueous radiation curable composition of the present invention further may comprise one or more photoinitiator(s), one or more silicone(s), one or more micro- scale particle(s) and/or one or more nano-scale particle(s), and one or more thermoplastic resins.

[0043] The photoinitiators for being used in the radiation curable dispersions of the present invention are of the unimolecular (type I) or of the bimolecular type (type II).

[0044] Photoinitiators which can easily be incorporated into aqueous coating compositions are preferred. Such products are, for example, Irgacure® 500 (a mixture of benzophenone and (1 -hydroxycyclohexyl) phenyl ketone, Ciba, Lampertheim, DE), Irgacure® 819 DW (phenyl-bis-(2,4,6-trimethylbenzoyl)-phosphine oxide, Ciba, Lampertheim, DE), Esacure® KIP EM (oligo-[2-hydroxy-2-methyl-1 -[4-(1 -methylvinyl)-phenyl]-propanone], Lamberti, Aldizzate, Italy), Esacure® KIP 100F (mixture of oligo [ 2-hydroxy-2-methyl-1 -[ 4-(1 - methylvinyl) phenyl] propanone] and 2-hydroxy-2-methyl-1 -phenyl propan-1 -one, Lamberti, Aldizzate, Italy). Mixtures of these compounds can also be employed.

[0045] The silicones for being used in the radiation curable dispersions of the present invention are preferably straight chain, cyclic, branched, dendritic, or network polysiloxane(s). Straight chain or a partially branched straight chain polysiloxanes are particularly preferred.

[0046] Unsubstituted monovalent hydrocarbyl groups and substituted monovalent hydrocarbyl groups are examples of the silicon-bonded organic groups.

[0047] The unsubstituted monovalent hydrocarbyl can be exemplified by CMO alkyl such as methyl, ethyl, n-propyl, isopropyl, butyl, t-butyl, hexyl, octyl, decyl; C3-io cycloalkyl such as cyclopentyl, cyclohexyl; C2-10 alkenyl such as vinyl, allyl, 5-hexenyl, 9-decenyl; Ce-ιο aryl such as phenyl, tolyl, xylyl; and C7-10 aralkyl such as benzyl, methylbenzyl, phenethyl.

[0048] Preferred there among are the CMO alkyl, Ce-ιο aryl, and C2-10 alkenyl, wherein methyl and phenyl are particularly preferred.

[0049] The substituted monovalent hydrocarbyl group can be exemplified by groups provided by replacing all or a portion of the hydrogen atoms in the aforementioned unsubstituted monovalent hydrocarbyl groups, and particularly in the CMO alkyl and phenyl, with a halogen atom, an epoxy functional group, a (meth)acrylic functional group, an amino functional group, a sulfur-containing functional group or a substituent group such as alkoxy, hydroxycarbonyl and alkoxycarbonyl.

[0050] Preferred there among is a (meth)acrylic functional, more preferred an acrylic functional group.

[0051] Preferred polysiloxanes include polymers and copolymers comprising dimethylsiloxane units, methylhydrogensiloxane units, diphenylsiloxane units, phenylmethylsiloxane units, dimethylhydrogensiloxane units and trimethylsiloxane units.

[0052] The micro- or nano-scale particles suitable for practicing the present invention include glass spheres, plastic particles such as polyamide or polytetrafluorethylene powders, silicon carbide, metal oxides, or salts thereof. Non-limiting examples of suitable metal oxides include silicon oxide, aluminum oxide, tin oxide, zinc oxide, bismuth oxide, titanium oxide, zirconium oxide, lanthanide ("rare-earth") oxides, mixtures thereof, and the like; other suitable metal salts such as calcium carbonate, calcium aluminate, magnesium aluminosilicate, potassium titanate, cerium ortho-phosphate, hydrated aluminum silicate, metal salt clays such as montmorillonite, illite, Kaolin clay, halloysite

2), mixtures thereof, and the like; and mixtures of metal oxides with metal salts.

[0053] The term "micro-scale particles" refers to particles having an average particle size of about 0.1 to about 100 μηη. The term "nano-scale particles" refers to particles having an average particle size of about 1 to about 100 nm.

[0054] Particles suitable for being used in the radiation curable dispersions of the present invention are micro-scale particles, nano-scale particles or a mixture thereof having an average particle size of from about 5 nm to about 50 μηη. Preferably the particles can have an average particle size of from about 10 nm to about 30 μηη.

[0055] The particles can be spheroidal or non-spheroidal, e.g., irregularly shaped particles. The term "average particle size" refers to the size of primary particles, as they would be classified by means known in the art, and is not the size of agglomerates.

[0056] The micro-scale particle particles and/or nano-scale particles preferably used in the radiation curable dispersions of the present invention are micro glass spheres and/or fumed silica nano-scale particles.

[0057] The average particle size is related to the layer thickness of the cross- linked coating and is comprised between 0.02 and 200%, preferably between 0.04 and 170%, more preferably between 0.06 and 130% and most preferably between 0.08 and 100% of the coating layer thickness.

[0058] Without being bound by any theory, the inventor is of the opinion that migration of nano-scale or micro-scale particles to the surface of the top-layer during evaporation of water from the radiation curable aqueous polyurethane dispersion and that blocking of said particles at the surface of said top-layer, upon cross-linking, contributes to the anti-slip and scuff resistance properties.

[0059] The thermoplastic resins for being used in the radiation curable dispersions of the present invention are homo- or copolymer(s) comprising one or more vinyl alkanoate(s) selected from the group consisting vinyl acetate, vinyl propionate and vinyl butyrate and/or one or more vinyl acetal(s) selected from the group consisting of vinyl formal, vinyl acetoacetal, vinyl propyral and vinyl butyral, and/or vinyl alcohol. The thermoplastic resin preferably used in the coating composition of the present invention is polyvinyl acetate, polyvinyl butyrate and/or polyvinyl butyral.

[0060] The aqueous radiation curable dispersions preferably comprise from 0.5 to 10% by weight, preferably from 2 to 8% by weight of at least one photoinitiator, relative to the total weight of the radiation curable dispersion, including water.

[0061] The polyurethane comprising top-layer of the decorative substrates of the present invention in general is obtained from irradiating one or more radiation curable dispersion(s).

[0062] For the preferred case where one radiation curable polyurethane dispersion is applied, said dispersion further comprises from 0.1 to 20% by weight of one or more micro-scale particle(s), nano-scale particle(s) or a mixture thereof, from 0.1 to 15% by weight of one or more silicone(s) and up to 15% by weight, preferably between 0.2 and 15% by weight of one or more thermoplastic resin(s), relative to the total weight of the radiation curable dispersion, including water.

[0063] For the particular case where two radiation curable polyurethane dispersions are applied, the first dispersion, entailing the anti-scuff properties, further comprises from 0.1 to 15% by weight of one or more silicone(s) and up to 15% by weight, preferably between 0.2 and 15% by weight of one or more thermoplastic resin(s), whereas the second dispersion, entailing the anti-slip properties, further comprises from 0.1 to 20% by weight of one or more micro-scale particle(s), nano-scale particle(s) or a mixture thereof; all weight percentages being expressed relative to the total weight of the radiation curable dispersion, including water.

[0064] The radiation curable polyurethane dispersion of the present invention further may comprise additives such as curing accelerators, flow agents, wetting agents, antifoaming agents, levelling agents, matting agents, fillers and other customary coating auxiliaries.

[0065] The present invention provides decorative surface coverings, more particularly floor and wall coverings, comprising one or more layer(s) comprising one or more polyolefin(s) and/or one or more polyvinyl halide resins, said decorative surface coverings being mechanically embossed, and said decorative surface coverings comprising a particular polyurethane top-layer on the top-surface of said one or more layer(s), said polyurethane top- layer comprising micro and/or nano-scale particles, one or more silicone resins and optionally one or more thermoplastic resin(s), said polyurethane top-layer combining anti-slip properties and scuff resistance.

[0066] The average particle size of the micro- and/or nano-scale particles, comprised in the polyurethane top-layer, is related to the depth of the embossing of the decorative surface covering and is comprised between 0.01 and 200%, preferably between 0.05 and 150%, more preferably between 0.1 and 100% and most preferably between 0.2 and 50% of the embossing depth.

[0067] The polyurethane top-layer comprises either:

a first layer b.1 .), obtained from the first radiation curable dispersion, completely covering the top-surface of the one or more polymer layer(s) and a patterned second layer b.2.), obtained from the second radiation curable dispersion, atop of the first layer b.1 .); or:

- a patterned first layer b.1 .), obtained from the first radiation curable dispersion, partially covering the top-surface of the one or more polymer layer(s) and a second layer b.2.), obtained from the second radiation curable dispersion, atop of that part of the top- surface of the one or more polymer layer(s) that does not comprise the first layer b.1 .), wherein the first layer b.1.) comprises:

- 40 to 75% by weight, preferably 50 to 75% by weight of cross-linked polyurethane, said polyurethane comprising an anionic or cationic salt group; 0.1 to 20% by weight of one or more silicone(s); and

up to 20% by weight, preferably from 1 to 20% by weight of one or more thermoplastic resin(s); and

wherein said second layer b.2.) comprises:

60 to 90% by weight, preferably 70 to 90% by weight of cross-linked polyurethane, said polyurethane comprising an anionic or cationic salt group; and

[0068] The decorative surface coverings of the present invention, comprising both layers b.1 .) and b.2.), are characterized in that the ratio of the surface of the first layer b.1 .) over the surface the second layer b.2.) is comprised between 10 and 0.1 , preferably between 8 and 0.3, more preferably between 6 and 0.6 and most preferably between 4 and 1.

[0069] In the present invention the concept "first layer b.1.)" and "second layer b.2.)" does not reflect the relative position of each of said layers and only reflects their difference in composition. Dependent on the method used for obtaining the polyurethane top- layer, the second layer b.2.) is pattern positioned on top of the first layer b.1 .) or both layers, b.1.) and b.2.) are pattern positioned next to each other, both contacting the top-surface or the one or more polymer layer(s).

[0070] Preferably the polyurethane top-layer is a single layer a), obtained from a single radiation curable dispersion, completely covering the top surface of the one or more polymer layers, and comprising:

- 0.5 to 25% by weight of one or more types of micro-scale particle(s) and/or one or more types of nano-scale particle(s);

0.1 to 20% by weight of one or more silicone(s); and

up to 20% by weight, preferably from 1 to 20% by weight of one or more thermoplastic resin(s);

[0071] The present invention provides a method for the preparation of said decorative surface coverings.

[0072] The method comprises the following steps:

step 1 ): providing one or more layer(s) comprising one or more olefin (co)polymers and/or one or more vinyl halide (co)polymers,

- step 2): applying and curing one or more aqueous radiation curable polyurethane dispersion(s)

In said method, step 1 ) comprises 2 embodiments, whereas step 2) comprises 3 embodiments.

[0073] A first embodiment of step 1 ) comprises providing one or more polyolefin comprising layers. Said one or more polyolefin comprising layers preferably are produced via one or more processing machines comprising a series of calendar rolls, wherein one or more polyolefin comprising paste(s), are processed.

[0074] The set temperature of the calendering rolls in general is comprised between 140 and 200°C, preferably between 150 and 190°C, more preferably between 160 and 180°C.

[0075] The hot polyolefin comprising paste is prepared by compounding the one or more olefin (co)polymers, the filler(s), the lubricant(s) and the one or more additives in a suitable heated mixer, for example in a twin screw or a single screw extruder, a mixing bowl with heated jacket, a Banbury mixer, continuous mixer, a ribbon mixer or any combination thereof to form a blend.

[0076] The polyolefin comprising paste is obtained from melt-mixing at an internal temperature comprised between 180 and 240°C, preferable between 190 and 230°C, more preferable between 200 and 220°C. [0077] A second embodiment of step 1 ) comprises spreading out at least one vinyl chloride (co)polymer comprising plastisol on a backing layer and gelling said at least one plastisol layer at a temperature comprised between 130°C and 200°C. Hereto, the at least one vinyl chloride (co)polymer comprising plastisol is spread on a backing layer moving at around 15 to 25 meters per minute.

[0078] For multilayer decorative surface coverings at least one vinyl chloride

(co)polymer comprising plastisol is spread on the backing layer in several layers so that the floor covering is literally built up.

[0079] The multilayer product is first gelled by contact with one or more heated roll and then passed into an oven where they are gelled and fused at a temperature of from 130°C to 200°C.

[0080] Often the gelling is performed after the spreading of each individual layer starting with the base layer. After the gelling the next layer can be spread.

[0081] Typically vinyl chloride (co)polymer comprising plastisols are produced in batch processes using high shear mixing equipment. The mixing generally is performed for a period of from about 15 to about 60 minutes, whereupon the blend is cooled down. In general such process is used for making plastisols which are immediately further processed, since the high friction level of the mixing elements in the plastisol results in high local temperature increase which generally results in poor viscosity stability of the plastisol on storage.

[0082] On the other hand, storage stable plastisols can be prepared by blending the finely divided vinyl chloride (co)polymer, optionally otherfinely divided solid materials, liquid plasticizer blend and optionally other liquid materials in a blending tank with low shear. The pre-homogenized plastisol is recirculated from the blending tank through a dynamic mixer back into the blending tank. This recirculation is performed up to 10 times prior to discharging the final plastisol.

[0083] The vinyl chloride (co)polymer comprising plastisol may be phthalate-free plastisol.

[0084] The vinyl chloride (co)polymer comprising plastisol may be a phthalate- free polyvinyl chloride comprising plastisol.

[0085] To the top-surface of the one or more layers of step 1 ), standing at a temperature comprised between 25 and 60°C, preferably between 30 and 50°C, the one or more radiation curable polyurethane dispersion(s) of the present invention, is (are) homogeneously applied in step 2).

[0086] For the preparation of the radiation curable polyurethane dispersion(s) one or more components selected from the group consisting of micro-scale particle(s), nano- scale particle(s), silicone(s), thermoplastic resin(s) and additives are admixed to the polyurethane dispersion. Mixing can be carried out simply by stirring. Mixing the components can be carried out preferably directly before the application. Prior to the application, if necessary, water and/or organic solvents may in general still be used for adjusting the viscosity.

[0087] A first embodiment of step 2) comprises:

- applying a first aqueous polyurethane dispersion, comprising one or more silicones and optionally one or more thermoplastic resins, on the surface of the one or more polymer layer(s),

- irradiating the ethylenically unsaturated polyurethane composition to form the first layer b.1 .),

applying a second aqueous polyurethane dispersion, comprising nano-scale and/or micro-scale particles, on the surface of the first layer b.1 ) according to a pattern of covered and uncovered areas,

- evaporating water from the second aqueous dispersion to form an uncured patterned second layer comprising an ethylenically unsaturated polyurethane,

irradiating the ethylenically unsaturated polyurethane to form a cross-linked polyurethane top-layer, comprising the cross-linked first layer b.1 ) with the cross-linked patterned second layer b.2.) atop;

[0088] The radiation dose for converting the ethylenically unsaturated polyurethane, obtained from evaporating waterfrom the first aqueous polyurethane dispersion, into the first layer b.1 .), is selected in such a way, that said first layer b.1.), after irradiation, is characterized by a degree of cross-linking of at least 5%, preferably at least 10%, more preferably at least 20% and most preferably at least 40%, before the patterned application of the second aqueous polyurethane dispersion.

[0089] In a particular variant of the first embodiment of step 2), the radiation dose equals 0 mJ/cm² meaning that the second aqueous polyurethane dispersion is patterned applied on the surface of the uncured first layer b.1 ).

[0090] A second embodiment of step 2) comprises:

- patterned applying the first and the second aqueous polyurethane dispersion on the surface of the one or more polymer layer(s),

irradiating the ethylenically unsaturated polyurethane to form a cross-linked polyurethane top-layer, comprising patterned cross-linked first layer b.1 ) and patterned cross-linked second layer b.2.);

[0091] A particular variant of the second embodiment of step 2) comprises: applying the first aqueous polyurethane dispersion on the surface of the one or more polymer layer(s), according to a pattern of covered and uncovered zones

evaporating water from the first aqueous dispersion to form an uncured patterned first layer comprising an ethylenically unsaturated polyurethane,

- optionally irradiating the ethylenically unsaturated polyurethane to form a patterned first layer b.1 .).

applying the second aqueous polyurethane dispersion on these parts of surface of the one or more polymer layer(s) that do not comprise the patterned polyurethane first layer b.1 ),

irradiating the ethylenically unsaturated polyurethane to form a polyurethane top-layer, comprising patterned crosslinked first layer b.1 ) and patterned cross-linked second layer b.2.).

[0092] A third and preferred embodiment of step 2) comprises:

applying an aqueous polyurethane dispersion, comprising micro- and/or nano-scale particles, one or more silicone(s) and optionally one or more thermoplastic resin(s), on the surface of the one or more polymer layer(s),

irradiating the ethylenically unsaturated polyurethane to form a cross-linked polyurethane top-layer a).

[0093] The radiation curable polyurethane dispersions of the present invention may be applied by any suitable coating process known to those of ordinary skill in the art, for example by direct gravure coating, reverse gravure coating, offset gravure coating, smooth roll coating, curtain coating, spray coating and combinations thereof. Direct gravure coating and smooth roll coating are preferred.

[0094] After evaporation of water, in a convection oven at about 100°C the decorative surface covering comprising the uncured polyurethane, standing at a temperature comprised between 20 and 70°C, preferably between 30 and 60°C, is subjected to actinic radiation, and finally is cooled down to about room temperature.

[0095] In a preferred embodiment of the method of the present invention, the one or more layer(s) comprising the uncured polyurethane, after evaporation of water, is heated to a temperature comprised between 130 and 200°C, and subsequently is mechanically embossed.

[0096] Mechanical embossing is performed by pressing a texture into the plasticized polyvinyl chloride layer comprising the ethylenically unsaturated polyurethane layer atop. Embossing is carried out at a pressure comprised between 10 and 25 kg. cm^-2 and surface temperature comprised between 130°C and 200°C.

[0097] The apparatus for mechanically embossing a substrate in general includes a cooled embossing roller and a backup roller operatively positioned within the embossing roller such that a nip is formed between the backup roller and the embossing roller whereby the substrate may pass through the nip and engage the embossing rollerfor imparting a mechanically embossed pattern. The apparatus further includes a profilometer capable of quantifying the mechanically embossed pattern as the substrate is being embossed.

[0098] In general the texture obtained from mechanical embossing is characterized by a depth comprised between about 10 to 100 μηη, a width comprised between about 125 to 400 μηη, a wall angle (angle relative to surface) comprised between about 5 to 40 degrees and a frequency of about 4 to 20 features per cm.

[0099] After mechanical embossing the ethylenically unsaturated polyurethane resin, standing at a temperature comprised between 20 and 70°C , preferably between 30 and 60°C, is cross-linked by exposure to actinic radiation such as ultraviolet (UV) radiation with a wavelength of for instance 250-600 nm.

[0100] Examples of radiation sources are medium and high-pressure mercury vapor lamps, lasers, pulsed lamps (flashlight), halogen lamps and excimer emitters.

[0101] Preferably, within the context of the present invention, one or more medium pressure mercury vapour UV radiators of at least 80 to 250 W/linear cm are used.

[0102] Preferably said medium pressure mercury vapour UV radiator(s) is (are) positioned at a distance of from about 5 to 20 cm from the substrate. The irradiating time period preferably is comprised between 1 and 60 seconds for having a radiation dose in the range of from 80 to 3000 mJ/cm².

[0103] On the other hand the ethylenically unsaturated polyurethane layer can be cured by bombardment with high-energy electron beams (EB) at for instance 150-300 keV. For this particular case, coating compositions, in which the photoinitiators have been omitted, are cured.

[0104] In general the thickness of the polyurethane top coat is comprised between 3 and 30 microns, preferable between 8 and 20 microns.

[0105] In a particular embodiment of the present invention, the top surface of the one or more layers is subjected to a plasma treatment, preferably a corona treatment, adjusted to provide a surface energy of at least 38 mN/m, preferably of at least 40 mN/m, more of at least 42 mN/m, according to ASTM D2578.

[0106] Corona treatment is of particular interest for the one or more layers of step a) comprising one or more olefin (co)polymers. [0107] Corona plasma treatment ideally is done on-line immediately before initiation of step b) i.e. before application of the aqueous radiation curable polyurethane dispersion.

Example

[0108] The following illustrative example are merely meant to exemplify the present invention but are not destined to limit or otherwise define the scope of the present invention.

Example: Preparation of a stack of adjacent polyolefin layers.

[0109] A halogen-free paste formulation, according to the formulation as given in table 1 , is prepared by melt-mixing wherein the internal temperature of said paste is about 200°C.

[0110] In table 1 , Clearflex® CLDO is very low density polyethylene, with a density of 0.900 g/cm3 from Polimeri; Greenflex® ML 50 is a copolymer of ethylene and vinyl acetate from Polymeri Europa; TafmerTM DF 710 is an ethylene-butene elastomerfrom Mitsui Company; Fusabond® 525 is a maleic anhydride modified ethylene copolymer from Dupont Company; Chalk Superfine is calcium carbonate from Omya; Zinc Oxide Neige A is Zinc oxide from Umicore; Paraffin is a mineral parrafinic process oil from Petrocenter; Radiacid® 0444 is stearic acid from Oleon and Irganox® 1010 is a sterically hindered phenolic antioxidant from BASF.

[0111] A glass fiber mat was supplied by JohnsMainville (also called JS) under their designation SH 35/3 having an air permeability of 4500 l/m².s;

[0112] The PVC-free paste of the composition as in table 1 has a dynamic viscosity at 200°C and a at shear rate of 100/s of 1500 Pa.s. [0113] The glass fiber mat was impregnated with the PVC- free paste of table 1 using the calendaring process wherein the temperature of the cylinders were respectively 170 and 175°C.

[0114] The carrier comprising layer thus obtained, with an overall thickness of about 1.2 mm then was subjected to a second calendaring step wherein a layer of about 0.5 mm of halogen-free paste of table 1 was applied on the remaining exposed side of the 1.2 mm carrier comprising layer. The reinforced layer thus obtained has an overall thickness of about 1 .7 mm.

[0115] The reinforced layer, was then transformed into a decorative surface covering through the application of a top layer.

[0116] Hereto a coextruded film of 250 μηη of Surlyn^® 9020, a zinc ionomer ethylene-(meth)acrylic acid-(meth)acrylate thermoplastic resin and 50 μηη of Bynel^® 2022, an ethylene-(meth)acrylic acid-(meth)acrylate terpolymer, both form Dupont was contacted, with its 50 μηη Bynel^® 2022 side, with the 0.5 mm side of the reinforced layer, which first was heated to about 100°C by means of infrared irradiation. The top layer then was pressed onto the reinforced layer and subsequently heated, for 2.5 minutes, in an oven at an ambient temperature comprised between 160 and 200°C.

[0117] After cooling down the above polyolefin stack, the top surface of the top layer was corona treated for 1 second, using a Corona Lab System from Dyne Technology Ltd., whereupon the surface energy increased from 36 mN/m to 41 mN/m.

[0118] Subsequently the radiation curable aqueous polyurethanes dispersion with the composition as in table 2, were applied by a smooth roll coating process under conditions to have a dry coating thickness comprised between 10 and 12 μηη.

[0119] The numbers in table 2 are expressed in percent by weight.

[0120] The radiation curable polyurethane dispersion of composition 1 and composition 2 are each used individually on the above stack of adjacent polyolefin layers, resulting in decorative surface 1 and decorative surface 2 respectively;

Table 2 Composition 1 Composition 2

UV-PUD 89.6 77.2

pH stabilizer 0.2 0.2

Silicone 0.6 2.1

Defoamer 0.9 0.8

Silicon surfactant 0.6 0.5

Matting agent 0.9

Nano/micro particle 2.6 2.4

Photoinitiator 2.3 2.0

Reactive diluent 2.3 2.0

Thermoplastic resin 12.8

[0121] In table 2: the ultra-violet curable polyurethane dispersion is Bayhydrol^®

UV 2720/1 XP from Bayer characterized by a solid content of 40%; the pH stabilizer is AMP 90^® is a 90% 2-amino-2-methyl-1 -propanol solution in water from Angus Chemie GmbH; the defoamer is Neocryl^® AP 2861 from DSM Coating Resins; the silicon surfactant is Byk^®-348 from Byk Chemie; the photoinitiator is Esacure® KIP 100 F from Lamberti; and the reactive diluent is Sartomer^® SR 238 (HexaneDiolDiAcrylate) from Arkema.

[0122] In composition 1 the silicone is 1/1 mixture of Byk-LP G 22702, a silicone emulsion from Byk Chemie, and Silmer Acr Di-2510, an acrylate functional polydimethylsiloxane from Siltech Corp.; the nano/micro particle is a mixture comprising 77 % by weight of Microperl^® 050-20-215, coated solid glass beads with a particle size of about 20 μηη, from Solvitec and 23 % by weight of Aerosil^®200 (fumed silica) from Evonik; and the matting agent is a mixture comprising 55% by weight of Acematt^®TS 100 from Evonik and 44% by weight of Deuteron^® MK from Deuteron

In composition 2 the thermoplastic resin is SharkDispersionMW™, recycled polybutyral, from Shark^® Solutions

[0123] The respective radiation curable polyurethane dispersions each individually are applied on the corona treated top surface of the halogen-free layer stack standing at about 50°C.

[0124] After evaporation of the water, in a convection oven at about 100°C, the halogen-free layer stacks, comprising the respective uncured ethylenically unsaturated polyurethane resin, are mechanically embossed at a pressure of about 15 kg. cm^-2 while standing at a temperature of about 160°C and subsequently subjected for 6 seconds to irradiation with ultraviolet light emitted by a 160 W/cm medium pressure mercury vapor UV- bulb (Fusion UV Systems Ltd) with a total UV dose of 1500 mJ/cm² while standing at a temperature of 40°C.

[0125] The anti-slip properties of the decorative surface covering of the present invention were assessed according to DIN 51 130:2010 "Testing of floor coverings - Determination of the anti-slip property - Workrooms and fields of activities with slip danger, walking method - Ramp test^''

[0126] In this method a test person with test shoes walks forwards and backwards in an upright position over the floor covering to be tested, the slope of which is increased from the initial horizontal state to the acceptance angle ( = angle of inclination until the limit of safe walking is reached and the test person slips). The acceptance angle is determined on floor coverings on which a lubricant has been applied.

[0127] For this test method the below evaluation criteria apply:

[0128] For both decorative surface covering (decorative surface 1 and decorative surface 2), prepared according to the method of the present invention, a resistance class equal to or superior to R9 was recorded.

[0129] The scuff resistance is assessed using a friction test apparatus wherein an Astral rubber tool with thickness of 5 mm and a width of 0.8 mm, while subjected to a loading of "Y" kg is moved "X" times over 25 cm over the test area at a speed of 0.40 m/s.

[0130] In the test the rubber tool, before touching the test panel (39x39 cm) is moved over 2 cm of abrasive paper (P600)

[0131] The complete test consists of:

[0132] After each test series (for example 6 times with a 9 kg loading) the test panel is visually evaluated on a 0 to 3 scale where:

0 results in severe damage

1 results in damage

2 results in slight damage

3 results in no visual damage

[0133] Finally the test result of the respective series are added together for a final result comprised between 0 and 15.

[0134] For the decorative surface covering, prepared according to the method as described above, a final scuff resistance of 12 was recorded for decorative surface 1 while a final scuff resistance of 1 1 was recorded for decorative surface 2; the values for the final scuff resistance are obtained from:

The respective evaluations in the above table and the final scuff resistance value is the average of 3 measurements.

Claims

1 . A decorative surface covering, in particular floor or wall covering, comprising one or more polymer layer(s) and a polyurethane top-layer completely covering the top surface of the one or more polymer layers, said top-layer comprising:

- 0.1 to 20% by weight of one or more silicone(s).

2. The decorative surface covering according to claim 1 wherein the polyurethane top-layer is a single layer comprising:

0.1 to 20% by weight of one or more silicone(s).

3. The decorative surface covering according to claim 1 wherein the polyurethane top-layer comprises a first layer b.1 .) completely covering the top-surface of the one or more polymer layer(s) and a patterned second layer b.2.) atop of the first layer b.1 .), wherein said first layer b.1 .) comprises:

0.1 to 20% by weight of one or more silicone(s); and

wherein said second layer b.2.) comprises:

4. The decorative surface covering according to claim 1 wherein the polyurethane top-layer comprises a patterned first layer b.1.) partially covering the top-surface of the one or more polymer layer(s) and a second layer b.2.) atop of that part of the top-surface of the one or more polymer layer(s) that does not comprise the first layer b.1 .) wherein said first layer b.1 .) comprises: 40 to 75% by weight of cross-linked polyurethane, said polyurethane comprising an anionic or cationic salt group;

0.1 to 20% by weight of one or more silicone(s); and

wherein said second layer b.2.) comprises:

- 60 to 90% by weight of cross-linked polyurethane, said polyurethane comprising an anionic or cationic salt group; and

5. The decorative surface covering according to any of claims 1 to 4 wherein the polyurethane top-layer comprises from 1 to 20% by weight of one or more thermoplastic homo- or copolymer(s) comprising one or more vinyl alkanoate(s) selected from the group consisting of vinyl acetate, vinyl propionate and vinyl butyrate and/or one or more vinyl acetal(s) selected from the group consisting of vinyl formal, vinyl acetoacetal, vinyl propyral and vinyl butyral, and/or vinyl alcohol.

6. The decorative surface covering according to any of claims 1 to 5 wherein the types of one or more micro- and/or nano-scale particles are selected from the group consisting of glass particles, plastic particles, metal oxide particles, metalloid oxide particles and metal salt particles and mixings thereof.

7. The decorative surface covering according to any of claims 1 to 6 wherein the average particle size of the micro- and or nano-scale particles is comprised between 0.02 and 200%, preferably between 0.04 and 170%, more preferably between 0.06 and 130% and most preferably between 0.08 and 100% of the cross-linked polyurethane layer thickness.

8. The decorative surface covering according to any of claims 1 to 7 wherein the one or more silicone(s) comprise one or more polyorganosiloxanes.

9. The decorative surface covering according to any of claims 1 to 8 wherein the one or more polymer layer(s) comprise(s) one or more polymers selected from the group consisting of polyvinyl halides, polyolefins and block copolymers comprising polymer blocks of one or more vinyl aromatic monomer(s) and polymer blocks of one or more alkylene(s).

10. The decorative surface covering according to any of claims 1 to 9 comprising an embossed structure.

1 1 . The decorative surface covering according to any of claims 1 to 10 wherein the average particle size of the micro- and or nano-scale particles is comprised between 0.01 and 200%, preferably between 0.05 and 150%, more preferably between 0.1 and 100% and most preferably between 0.2 and 50% of the embossing depth.

12. Method for the preparation of the decorative surface coverings according to claims 1 to 1 1 comprising the steps of providing one or more polymer layer(s), and

or

applying a second aqueous polyurethane dispersion on the surface of the first layer b.1 ) according to a pattern of covered and uncovered zones,

13. The method according to claim 12 wherein the aqueous radiation curable polyurethane dispersion comprises 20 to 80% by weight, preferably 25 to 60% by weight of radiation curable compounds and from 0.5 to 10% by weight, preferably from 2 to 8% by weight of at least one photoinitiator, relative to the total weight of the dispersion.

14. The method according to claim 12 or 13, wherein the radiation curable compounds of the aqueous radiation curable polyurethane dispersion comprise at least 65% by weight, preferably at least 76% by weight of one or more ethylenically unsaturated polyurethane resin(s) and at most 35% by weight preferably at most 24% by weight of one or more reactive diluent(s).

15. The method according to any of claims 12 to 14 wherein the aqueous radiation curable polyurethane dispersion comprises:

from 0.1 to 20% by weight of one or more micro-scale particle(s) and/or nano-scale particle(s), for the formation of second layer b.2.).