Method for producing a decorative surface

Abstract

A method for manufacturing a decorative surface, comprising the steps of: inkjet printing an image on a first thermoplastic foil by jetting one or more pigmented free radical curable inkjet inks on the first thermoplastic foil and curing them; applying a free radical curable liquid on the inkjet printed image and curing it as an adhesive layer; and hot pressing the first thermoplastic foil with a second thermoplastic foil into a decorative laminate; wherein at least one of the first and second thermoplastic foils is a transparent thermoplastic foil; wherein the one or more pigmented free radical curable inkjet inks contain a color pigment and a polymerizable composition containing 10 wt % to 90 wt % of one or more monofunctional polymerizable compounds; and wherein the free radical curable liquid contains a polymerizable composition containing 15 wt % or more of a multifunctional polymerizable compound and 15 wt % or more of a specific monofunctional polymerizable compound.

Description

Technical Field

[0001] The invention relates to a method for producing decorative surfaces, in particular decorative panels of PVC (polyvinyl chloride), also called vinyl tiles or vinyl tapes, for which the abbreviation LVT (luxury vinyl tile) is often used. Background Art

[0002] Decorative panels for furniture and flooring have traditionally been manufactured using gravure printing to provide a decorative image, usually of wood, to the decorative panel. For the manufacture of wood-based decorative panels, industrial inkjet printing systems have been introduced because of the flexibility they offer in use, such as variable data printing which enables short production runs and the production of personalised products at low cost.

[0003] The main disadvantage of these wood-based and paper-based decorative panels is their limited water resistance, which prevents their use in bathrooms and kitchens. This problem has been solved with gravure-printed LVT, in which the decorative image is laminated between two PVC sheets.

[0004] To date, industrial inkjet printing systems have not been used for LVT due to adhesion issues between the decorative image and the PVC sheet.

[0005] Several aqueous inkjet technologies suitable for wood-based decorative panels have been explored for improving the adhesion of LVT panels, such as in EP 2925529 A (CERALOC INNOVATION), EP 3693180 A (UNILIN) and EP 3095613 A (AGFA). EP 3271188A (TARKET) discloses a primer layer that improves the printability of a floor or wall covering material by an aqueous ink composition, the primer layer comprising one or more acrylic copolymers and silica, and the covering material comprising polyvinyl chloride. However, although some aqueous inkjet technologies provide improved adhesion, the water resistance of such panels is generally reduced because the hydrophilic layer tends to swell when exposed to water. Furthermore, EP 3738782 A (SIHL) discloses the use of a microporous ink-receiving layer comprising inorganic particles and a binder, and further comprising greater than 6 wt. % of a polymerizable and / or crosslinkable monomer or polymer compound having at least one (meth)acrylate moiety or a polymer crosslinked via a (meth)acrylate moiety, based on the weight of the ink-receiving layer.

[0006] The use of UV curable inkjet systems has also been proposed, for example in EP 3095614 A (AGFA).However, further measures are needed for improving the adhesion of LVT printed with UV curable inkjet inks to a commercially acceptable level.

[0007] EP 3173229 A (TARKETT) discloses a method for producing LVT, wherein the decorative layer is printed with a UV curable ink, and wherein the UV curing is performed with a UV LED source spectrally emitting in the range of 345-420 nm, so that the UV curable ink is not yet fully cured during lamination. However, this method makes it susceptible to scratching and dust problems in an industrial environment.

[0008] In EP 3300916 A (AGFA), an additional adhesive layer containing vinyl chloride-vinyl acetate-vinyl alcohol copolymer is applied on top of the cured UV inkjet ink to improve adhesion. However, this adhesive layer is coated from an organic solvent, which is not preferred due to safety risks in an industrial environment.

[0009] Therefore, there remains a need for improved methods of making decorative laminates using inkjet technology that exhibit good water resistance and adhesion without the need for organic solvents. Summary of the invention

[0010] In order to overcome the above problems, a preferred embodiment of the present invention has been achieved with a method for decorating a surface as defined in claim 1 .

[0011] Surprisingly, it has been found that the use of a free radical curable liquid having a specific polymerizable composition without color pigments or polymer dispersants allows good adhesion properties to be obtained in the lamination of a UV curable inkjet printed PVC sheet with a second PVC sheet, provided that the UV curable inkjet ink contains a specific polymerizable composition. The inventors believe that this can be explained by the weak boundary layer theory. The color pigments and polymer dispersants in the ink layer are concentrated near the bonding surface and form a weak connection with the PVC sheet to be laminated thereon.

[0012] Other advantages and embodiments of the present invention will become apparent from the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 A cross section of a decorative panel (1) is shown, comprising a base layer (2) with a tongue (3) and a groove (4), the base layer being laminated on the top side with a transparent or opaque thermoplastic foil (5) and a transparent thermoplastic foil (6), wherein a decorative layer (7) is located between the transparent or opaque thermoplastic foil (5) and the transparent thermoplastic foil (6). The decorative layer (7) comprises a colored pattern and an adhesive layer.

[0014] Figure 2 Four ways are shown how the invention can be implemented.

[0015] Figure 2.A shows the hot pressing of an assembly between an upper hot press plate (10) and a lower hot press plate (16), the assembly comprising a transparent thermoplastic foil (11), a transparent or opaque thermoplastic foil (14) carrying a colored pattern (13) and an adhesive layer (12), and a base layer (15).

[0016] Figure 2 .B shows the hot pressing of an assembly between an upper hot pressing plate (10) and a lower hot pressing plate (16), the assembly comprising a transparent thermoplastic foil (11) carrying a colored pattern (13) and an adhesive layer (12), a transparent or opaque thermoplastic foil (14) and a base layer (15).

[0017] Figure 2 .C shows the hot pressing of an assembly comprising a transparent thermoplastic foil (11) and a base layer (15) carrying a colored pattern (13) and an adhesive layer (12) between an upper hot press plate (10) and a lower hot press plate (16).

[0018] Figure 2 .D shows the hot pressing of an assembly comprising a transparent thermoplastic foil (11) carrying a colored pattern (13) and an adhesive layer (12) and a base layer (15) between an upper hot press plate (10) and a lower hot press plate (16). DETAILED DESCRIPTION

[0019] definition

[0020] The term "monofunctional polymerizable compound" means that the polymerizable compound contains one polymerizable group.

[0021] The term "bifunctional polymerizable compound" means that the polymerizable compound contains two polymerizable groups.

[0022] The term "multifunctional polymerizable compound" in the present invention means that the polymerizable compound contains two or more polymerizable groups.

[0023] The term "alkyl" means all possible variations for each number of carbon atoms in the alkyl group, i.e., methyl; ethyl; for three carbon atoms: n-propyl and isopropyl; for four carbon atoms: n-butyl, isobutyl and tert-butyl; for five carbon atoms: n-pentyl, 1,1-dimethyl-propyl, 2,2-dimethylpropyl and 2-methyl-butyl, etc.

[0024] Unless otherwise stated, substituted or unsubstituted alkyl is preferably C1-C6-alkyl.

[0025] Unless otherwise stated, substituted or unsubstituted alkenyl is preferably C2-C6-alkenyl.

[0026] Unless otherwise stated, substituted or unsubstituted alkynyl is preferably C2-C6-alkynyl.

[0027] Unless otherwise specified, substituted or unsubstituted aralkyl is preferably phenyl or naphthyl which contains one, two, three or more C1-C6-alkyl groups.

[0028] Unless otherwise specified, the substituted or unsubstituted alkaryl group is preferably a C7-C8 group including a phenyl group or a naphthyl group. 20 -alkyl.

[0029] Unless otherwise specified, substituted or unsubstituted aryl is preferably phenyl or naphthyl.

[0030] Unless otherwise specified, the substituted or unsubstituted heteroaryl group is preferably a five- or six-membered ring substituted with one, two or three oxygen atoms, nitrogen atoms, sulfur atoms, selenium atoms or a combination thereof.

[0031] The term "substituted" in, for example, a substituted alkyl group means that the alkyl group may be substituted with atoms other than the atoms normally present in this group (i.e., carbon and hydrogen). For example, a substituted alkyl group may contain halogen atoms or thiol groups. Unsubstituted alkyl groups contain only carbon and hydrogen atoms.

[0032] Unless otherwise indicated, substituted alkyl, substituted alkenyl, substituted alkynyl, substituted aralkyl, substituted alkaryl, substituted aryl and substituted heteroaryl are preferably substituted with one or more components selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl and tert-butyl, ester, amide, ether, thioether, keto, aldehyde, sulfoxide, sulfone, sulfonate, sulfonamide, -Cl, -Br, -I, -OH, -SH, -CN and -NO2.

[0033] Manufacturing method

[0034] The method for producing a decorative surface according to a preferred embodiment of the present invention comprises the following steps:

[0035] - inkjet printing an image on the first thermoplastic foil by jetting one or more pigmented free radical curable inkjet inks onto the first thermoplastic foil and curing them;

[0036] - applying a free radical curable liquid over the inkjet printed image and curing it as an adherent layer; and

[0037] - hot pressing the first thermoplastic foil and the second thermoplastic foil into a decorative laminate;

[0038] wherein at least one of the first and second thermoplastic foils is a transparent thermoplastic foil;

[0039] wherein the one or more pigmented free radical curable inkjet inks comprise a colored pigment and a polymerizable composition containing from 10% to 90% by weight of one or more monofunctional polymerizable compounds;

[0040] wherein the radical curable liquid comprises a polymerizable composition containing 15 wt % or more of a multifunctional polymerizable compound and 15 wt % or more of a monofunctional polymerizable compound A or B;

[0041] wherein all weight percentages wt % are based on the total weight of the polymerizable composition in the pigmented free radical curable inkjet ink or the polymerizable composition in the free radical curable liquid;

[0042] Wherein the monofunctional polymerizable compound A is a compound according to formula (1):

[0043]

[0044] wherein R represents hydrogen or a methyl group; X represents oxygen or an NR'-group; L represents a divalent linking group having not more than 10 carbon atoms; R' is selected from hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted aralkyl, substituted or unsubstituted alkaryl and substituted or unsubstituted aryl or heteroaryl; n represents 0 or 1; and A represents a moiety according to formula (1A):

[0045]

[0046] wherein Q represents the atoms necessary to form a five- to eight-membered ring, and the dashed lines represent covalent bonds to carbon atoms;

[0047] Wherein the monofunctional polymerizable compound B is a compound according to formula (2):

[0048]

[0049] wherein R2 represents hydrogen or methyl; L represents a divalent linking group having not more than 10 carbon atoms; n represents 0 or 1; and D represents a five- to seven-membered saturated heterocyclic ring containing a single ether group.

[0050] The thermoplastic foil may be a cast polypropylene (cPP) film, a polyester film (PET) or a polyvinyl chloride (PVC) film, also including a biaxially oriented polypropylene (BOPP) film and a biaxially oriented polyester (BOPET) film. However, the best adhesion results are obtained with a PVC foil. The thickness of the thermoplastic foil is usually between 12 μm and 500 μm, typically between 30 μm and 300 μm.

[0051] In a preferred embodiment, the first and second thermoplastic foils comprise polyvinyl chloride.

[0052] like Figure 2 .C and Figure 2 As shown in FIG. 4 , the substrate can replace the role of one of the thermoplastic foils if the free radical curable inkjet ink exhibits sufficient adhesion to the substrate.

[0053] Free radical curable liquid

[0054] The free radical curable liquid differs from free radical curable inkjet inks in that it imparts no color when applied to a white substrate.The absence of color pigments and dispersants in the free radical curable liquid improves the adhesion of the decorative laminate.

[0055] The radical curable liquid used in the present invention comprises a polymerizable composition containing 15 wt % or more of a multifunctional polymerizable compound and 15 wt % or more of a monofunctional polymerizable compound A or B;

[0056] wherein all weight percentages wt % are based on the total weight of the polymerizable composition in the free radical curable liquid;

[0057] Wherein the monofunctional polymerizable compound A is a compound according to formula (1):

[0058]

[0059] wherein R represents hydrogen or a methyl group; X represents oxygen or an NR'-group; L represents a divalent linking group having not more than 10 carbon atoms; R' is selected from hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted aralkyl, substituted or unsubstituted alkaryl and substituted or unsubstituted aryl or heteroaryl; n represents 0 or 1; and A represents a moiety according to formula (1A):

[0060]

[0061] wherein Q represents the atoms necessary to form a five- to eight-membered ring, and the dashed lines represent covalent bonds to carbon atoms;

[0062] Wherein the monofunctional polymerizable compound B is a compound according to formula (2):

[0063]

[0064] wherein R2 represents hydrogen or methyl; L represents a divalent linking group having not more than 10 carbon atoms; n represents 0 or 1; and D represents a five- to seven-membered saturated heterocyclic ring containing a single ether group.

[0065] In a preferred embodiment, the free radical curable liquid is heated to 45°C for 1,000 seconds.-1 The free radical curable liquid has a viscosity between 5 mPa.s and 15 mPa.s at a shear rate of 1.5 to 2.0. This viscosity allows the free radical curable liquid to be ejected by an industrial print head. If the free radical curable liquid is not applied by a print head, but by a coating technique or a printing technique (such as flexographic printing or gravure printing), a higher viscosity can be used to improve the layer quality.

[0066] It has been observed that excess surfactant can deteriorate the adhesion of the decorative laminate.In a preferred embodiment, the free radical curable liquid contains surfactant in an amount of no greater than 0.3 wt%, preferably 0 wt% to 0.2 wt%, based on the total weight of the free radical curable liquid.

[0067] Monofunctional polymerizable compound A

[0068] The monofunctional polymerizable compound A is a compound according to formula (1):

[0069]

[0070] wherein R represents hydrogen or a methyl group; X represents oxygen or an NR'-group; L represents a divalent linking group having not more than 10 carbon atoms; R' is selected from hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted aralkyl, substituted or unsubstituted alkaryl and substituted or unsubstituted aryl or heteroaryl; n represents 0 or 1; and A represents a moiety according to formula (1A):

[0071]

[0072] wherein Q represents the atoms necessary to form a five- to eight-membered ring and the dashed lines represent covalent bonds to carbon atoms.

[0073] In a preferred embodiment, R represents hydrogen. When R represents hydrogen, higher cure speeds are observed.

[0074] In a preferred embodiment, X represents oxygen. When X represents oxygen, higher cure speeds are also observed.

[0075] In an even more preferred embodiment, R represents hydrogen and X represents oxygen.

[0076] In a preferred embodiment, the divalent linking group L is preferably an unsubstituted straight carbon chain having no more than 10 carbon atoms, preferably having 1 to 6 carbon atoms, more preferably a group selected from -CH2-, -CH2-CH2- and -CH2-CH2-CH2-.

[0077] In another preferred embodiment, n represents 0 and more preferably R represents hydrogen.

[0078] In a particularly preferred embodiment, the monomer has a structure according to formula (1B)

[0079]

[0080] wherein Q represents atoms necessary to form a five- to eight-membered ring.

[0081] Preferred polymerizable compounds A are Table 1 Given in.

[0082] Table 1

[0083]

[0084]

[0085] (Meth)acrylate compounds are more preferred than (meth)acrylamide compounds. (Meth)acrylamide compounds can be prepared according to the following scheme disclosed in CN 108239236 (CHENGDU POLLOCK TECH CO), wherein R represents H:

[0086]

[0087] Or prepared by the following scheme:

[0088]

[0089] Step 1 consists of et al., Amino Acids, 40, 197-204 (2011) and Hyde et al., Organic Process Research and Development, 23, 1860-1871 (2019) and step 2 is disclosed by WO2018 / 132370 (ISP INVESTMENTS).

[0090] Particularly preferred monofunctional polymerizable compounds A are PCA-1, PCA-2, PCA-4, PCA-6 and PCA-1 1. Most preferred compounds are PCA-1, PCA-2 and PCA-6.

[0091] The monofunctional polymerizable compound A may also be used in combination with one or more other monofunctional polymerizable compounds A and / or with one or more monofunctional polymerizable compounds B.

[0092] The amount of monofunctional polymerizable compounds A and / or B is at least 15 wt%, preferably at least 20 wt%, and most preferably at least 24 wt%, based on the total weight of the free radical curable liquid polymerizable composition.

[0093] Monofunctional polymerizable compound B

[0094] The monofunctional polymerizable compound B is a compound according to formula (2):

[0095]

[0096] wherein R2 represents hydrogen or methyl; L represents a divalent linking group having not more than 10 carbon atoms; n represents 0 or 1; and D represents a five- to seven-membered saturated heterocyclic ring containing a single ether group.

[0097] In a preferred embodiment, R2 represents hydrogen. When R2 represents hydrogen, a higher cure speed is observed.

[0098] In a preferred embodiment, n represents 1.

[0099] In a preferred embodiment, the divalent connecting group L is preferably a straight carbon chain having no more than 10 carbon atoms, preferably having 1 to 6 carbon atoms, and is more preferably selected from -CH2-, -CH2-CH2-, -CH2-CH2-CH2-, -CH2-CH2-CH2-CH2- and -CH2-CH2-O-CH2-.

[0100] In an even more preferred embodiment, D represents a five-membered saturated heterocyclic ring containing a single ether group.

[0101] Particularly preferred polymerizable compounds B are Table 2 Given in.

[0102] Table 2

[0103]

[0104] The monofunctional polymerizable compound B may also be used in combination with one or more other monofunctional polymerizable compounds B and / or with one or more monofunctional polymerizable compounds A.

[0105] In a preferred embodiment, the free radical curable liquid does not contain a polymerizable compound B, but only contains one or more polymerizable compounds A. It has been observed that the printing reliability of the free radical curable liquid containing polymerizable compound B is not as good as the corresponding free radical curable liquid containing polymerizable compound A, especially when evaluating latency. Latency is the ability of a free radical curable liquid to print immediately without nozzle failure after being idle in a print head for a period of time. Poor latency is usually caused by the evaporation of the polymerizable compound from the nozzle in the print head.

[0106] Multifunctional polymerizable compounds

[0107] There is no practical limitation on the polyfunctional polymerizable compound. Any polyfunctional monomer and oligomer capable of free radical polymerization can be used as the polyfunctional polymerizable compound. Suitable polyfunctional polymerizable compounds can be any polyfunctional monomer and / or oligomer found in Polymer Handbook Vol. 1+2, 4th Edition, Wiley-Interscience, 1999, edited by J. BRANDRUP et al.

[0108] The multifunctional polymerizable compound may be selected from triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, polypropylene glycol diacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, neopentyl glycol diacrylate, dihydroxymethyl-tricyclodecane diacrylate, bisphenol A EO (ethylene oxide) adduct diacrylate, bisphenol A PO (propylene oxide) adduct diacrylate, hydroxy neopentyl glycol diacrylate, propoxylated neopentyl glycol diacrylate, alkoxylated dimethylol tricyclodecane diacrylate and polytetramethylene glycol diacrylate, trimethylolpropane triacrylate, EO-modified trimethylolpropane triacrylate, tri(propylene glycol) triacrylate, caprolactone-modified trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, pentaerythritol ethoxylated tetraacrylate, dipentaerythritol hexaacrylate, ditrimethylolpropane tetraacrylate, glycerol propoxylated triacrylate, alkane Oxylated cyclohexanone dimethanol diacrylate, caprolactam-modified dipentaerythritol hexaacrylate, alkoxylated cyclohexanone dimethanol diacrylate, alkoxylated hexanediol diacrylate, dioxanediol diacrylate, dioxanediol diacrylate, cyclohexanone dimethanol diacrylate, diethylene glycol diacrylate, neopentyl glycol diacrylate, vinyl ether acrylate, propoxylated glycerol triacrylate and propoxylated trimethylolpropane triacrylate, ditrimethylolpropane tetraacrylate, dipentaerythritol pentaacrylate, ethoxylated pentaerythritol tetraacrylate, methoxylated glycol acrylates and acrylates.

[0109] Preferred vinyl ether acrylates are those disclosed in US 6310115 (AGFA). A particularly preferred compound is 2-(2-vinyloxyethoxy)ethyl acrylate. Other suitable vinyl ether acrylates are those disclosed in columns 3 and 4 of US 6767980 B (NIPPON SHOKUBAI).

[0110] In a particularly preferred embodiment, the free radical curable liquid contains a multifunctional polymerizable compound selected from the group consisting of dipropylene glycol diacrylate, tricyclodecane dimethanol diacrylate, and 1,6-hexanediol diacrylate.

[0111] In the most preferred embodiment, the free radical curable liquid contains at least tricyclodecane dimethanol diacrylate as a multifunctional polymerizable compound. It has been observed that adhesion is maximized in the presence of such a polymerizable compound.

[0112] The polyfunctional polymerizable compound is present in an amount of at least 15 wt %, preferably 20 wt % to 80 wt %, more preferably 30 wt % to 70 wt %, and most preferably 40 wt % to 60 wt %, based on the total weight of the polymerizable composition in the free radical curable liquid. Within the preferred range, adhesion is maximized.

[0113] In a particularly preferred embodiment, the free radical curable liquid contains tricyclodecane dimethanol diacrylate in an amount of at least 15 wt%, preferably 20 wt% to 80 wt%, more preferably 30 wt% to 70 wt%, and most preferably 40 wt% to 60 wt%, based on the total weight of the polymerizable composition in the free radical curable liquid. In the preferred range, adhesion is maximized.

[0114] Other monofunctional polymerizable compounds

[0115] There is no practical limitation on other monofunctional polymerizable compounds. Any monofunctional monomers and oligomers capable of free radical polymerization can be used as other monofunctional polymerizable compounds. Suitable other monofunctional polymerizable compounds can be any monofunctional monomers and / or oligomers found in Polymer Handbook Vol. 1+2, 4th Edition, Wiley-Interscience, 1999, edited by J. BRANDRUP et al.

[0116] In a preferred embodiment, the other monofunctional polymerizable compounds include ethylenically unsaturated polymerizable groups selected from acrylates, methacrylates, acrylamides, methacrylamides, styryls, maleates, fumarates, itaconates, vinyl ethers, vinyl esters, allyl ethers, and allyl esters.

[0117] In a more preferred embodiment, the other monofunctional polymerizable compound is a monoacrylate, preferably selected from isoamyl acrylate, stearyl acrylate, lauryl acrylate, octyl acrylate, decyl acrylate, isoamylstylacrylate, isostearyl acrylate, 2-ethylhexyl-diglycol acrylate, 2-hydroxybutyl acrylate, 2-acryloyloxyethylhexahydrophthalic acid, butoxyethyl acrylate, ethoxydiethylene glycol acrylate, methoxydiethylene glycol acrylate, methoxypolyethylene glycol acrylate, methoxypropylene glycol acrylate, phenoxyethyl acrylate, tetrahydrofurfuryl acrylate, isobornyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, 2-acryloyloxyethylsuccinic acid, 2-acryloyloxyethylphthalic acid, 2-acryloyloxyethyl-2-hydroxyethyl-phthalic acid, lactone-modified flexible acrylates and tert-butylcyclohexyl acrylate.

[0118] Acrylamide or substituted acrylamides (such as acryloylmorpholine) can also be used as other monofunctional polymerizable compounds.

[0119] Particularly preferred other polymerizable compounds include compounds according to formula (2B):

[0120]

[0121] wherein R2 represents hydrogen or methyl; L represents a divalent linking group having no more than 10 carbon atoms; n represents 0 or 1; and D represents a three- to four-membered saturated heterocyclic ring containing a single ether group. Such cyclic ethers are not effective as monofunctional polymerizable compounds B by themselves, but when combined with one or more monofunctional polymerizable compounds A and / or B, can further improve adhesion. In a preferred embodiment, R2 represents hydrogen. When R2 represents hydrogen, a higher curing speed is observed.

[0122] In a preferred embodiment, n represents 1.

[0123] In a preferred embodiment, the divalent connecting group L is preferably a straight carbon chain having no more than 10 carbon atoms, preferably having 1 to 6 carbon atoms, and is more preferably selected from -CH2-, -CH2-CH2-, -CH2-CH2-CH2-, -CH2-CH2-CH2-CH2- and -CH2-CH2-O-CH2-.

[0124] Particularly preferred polymerizable compounds B are Table 3 Given in.

[0125] Table 3

[0126]

[0127] Free Radical Curable Inkjet Inks

[0128] The free radical curable inkjet ink of described one or more painted contains colored pigment as colorant and has the polymerizable composition of one or more monofunctional polymerizable compounds containing 10 % by weight to 90 % by weight.Therefore, this means that the free radical curable inkjet ink of painted contains the multifunctional polymerizable compound of at least 10 % by weight in the polymerizable composition.The multifunctional polymerizable compound of at least 10 % by weight is provided for ink layer with necessary cohesive strength.In order to maximize adhesion, the free radical curable inkjet ink of described one or more painted preferably contains one or more monofunctional polymerizable compounds of 40 % by weight to 80 % by weight of gross weight based on the polymerizable composition.

[0129] The one or more pigmented free radical curable inkjet inks preferably form an inkjet ink set with inkjet inks of different colors. The inkjet ink set may be a standard CMYK ink set, but is preferably a CRYK ink set, where the magenta (M) ink is replaced by a red (R) inkjet ink. The use of red inkjet ink enhances the color gamut of wood-based colored patterns, which represent most decorative laminates in flooring.

[0130] A particularly preferred ink set comprises a) a cyan free radical curable inkjet ink containing a copper phthalocyanine pigment or CI Pigment Blue 60; b) a red free radical curable inkjet ink containing a pigment selected from the group consisting of CI Pigment Red 122, CI Pigment Red 144, CI Pigment Red 176, CI Pigment Red 188, CI Pigment Red 207, CI Pigment Red 242, CI Pigment Red 254, CI Pigment Red 272 and mixed crystals thereof; c) a yellow free radical curable inkjet ink containing a pigment selected from the group consisting of The following pigments: CI Pigment Yellow 83, CI Pigment Yellow 97, CI Pigment Yellow 93, CI Pigment Yellow 110, CI Pigment Yellow 120, CI Pigment Yellow 150, CI Pigment Yellow 151, CI Pigment Yellow 154, CI Pigment Yellow 155, CI Pigment Yellow 175, CI Pigment Yellow 180, CI Pigment Yellow 181, CI Pigment Yellow 194, CI Pigment Yellow 213, CI Pigment Yellow 214 and mixed crystals thereof; and d) a black free radical curable inkjet ink containing a carbon black pigment.

[0131] For multi-pass inkjet devices, a smaller number of print heads allows for expansion of ink sets with different colors compared to simple pass inkjet devices. For example, the ink set may be CMRYK inkjet inks. Such an ink set allows accurate reproduction of both wood patterns and other "fashion" patterns with more vivid colors.

[0132] The inkjet ink set may be extended with other inks, such as brown, green, blue, violet and / or orange, to further expand the color gamut of the ink set.

[0133] The inkjet ink set can also be extended by a combination of full density inkjet inks with low density inkjet inks. The combination of dark inks and light inks and / or black inks and grey inks improves image quality by reducing particle size. A preferred ink set comprises a dark black inkjet ink and a light black inkjet ink, as this allows minimizing the increase in the number of print heads while still sufficiently reducing particle size based on the principle of undercolor removal.

[0134] In a preferred embodiment of the ink set, the radical curable liquid contains a polymerizable composition containing 20 wt % or more of a multifunctional polymerizable compound and 30 wt % or more of a monofunctional polymerizable compound A or B, based on the total weight of the polymerizable composition.

[0135] In a preferred embodiment, the one or more free radical curable inkjet inks are subjected to a temperature of 45° C. and 1,000 s -1 The viscosity of the free radical curable inkjet ink is between 5 mPa.s and 15 mPa.s at a shear rate of 1.3 %. This viscosity allows the free radical curable inkjet ink to be jetted by reliable industrial print heads.

[0136] The surface tension of the one or more free radical curable inkjet inks is preferably in the range of 18 mN / m to 35 mN / m at 25° C., more preferably in the range of about 20 mN / m to about 30 mN / m at 25° C. Within these ranges, good ink spreading is obtained on the thermoplastic foil.

[0137] Colored Pigments

[0138] The colored pigment can be black, cyan, magenta, yellow, red, orange, purple, blue, green, brown, mixed colors thereof, etc. The colored pigment can be selected from those disclosed in HERBST, Willy et al., Industrial Organic Pigments, Production, Properties, Applications. 3rd edition, Wiley-VCH, 2004. ISBN 3527305769.

[0139] Particularly preferred pigments for cyan aqueous inkjet inks are CI Pigment Blue 60 and copper phthalocyanine pigments, more preferably CI Pigment Blue 15:3 or CI Pigment Blue 15:4.

[0140] The red free radical curable inkjet ink preferably contains a pigment selected from the group consisting of CI Pigment Red 122, CI Pigment Red 144, CI Pigment Red 176, CI Pigment Red 188, CI Pigment Red 207, CI Pigment Red 242, CI Pigment Red 254, CI Pigment Red 272 and mixed crystals thereof.

[0141] The yellow free radical curable inkjet ink preferably contains a pigment selected from the group consisting of CI Pigment Yellow 83, CI Pigment Yellow 93, CI Pigment Yellow 97, CI Pigment Yellow 110, CI Pigment Yellow 120, CI Pigment Yellow 150, CI Pigment Yellow 151, CI Pigment Yellow 154, CI Pigment Yellow 155, CI Pigment Yellow 175, CI Pigment Yellow 180, CI Pigment Yellow 181, CI Pigment Yellow 194, CI Pigment Yellow 213, CI Pigment Yellow 214 and mixed crystals thereof.

[0142] For black inks, suitable pigment materials include carbon black, such as Regal from Cabot Co. TM 400R、Mogul TM L. Elftex TM 320, or Carbon Black FW18, Special Black from DEGUSSA Co. TM 250、Special Black TM 350、Special Black TM 550. Printex TM 25. Printex TM 35. Printex TM 55. Printex TM 90. Printex TM 150T, MA8 from MITSUBISHI CHEMICAL Co., and CI Pigment Black 7 and CI Pigment Black 11.

[0143] Mixed crystals may also be used. Mixed crystals are also known as solid solutions. For example, under certain conditions, different quinacridones mix with each other to form solid solutions, which are quite different from both physical mixtures of the compounds and from the compounds themselves. In a solid solution, the molecules of the components enter into the same crystal lattice, usually but not always the lattice of one of the components. The x-ray diffraction pattern of the resulting crystalline solid is characteristic of that solid and can be clearly distinguished from the pattern of a physical mixture of the same components in the same proportions. In such physical mixtures, the x-ray pattern of each component can be distinguished, and the disappearance of many of these lines is one of the criteria for the formation of a solid solution. A commercially available example is Cinquasia from Ciba Specialty Chemicals. TM Magenta RT-355-D.

[0144] Mixtures of pigments may also be used. For example, a black inkjet ink may contain a carbon black pigment and at least one pigment selected from a blue pigment, a cyan pigment, a magenta pigment and a red pigment. Such a black inkjet ink was found to allow easier and better color management of the wood color.

[0145] The pigment particles in a pigmented inkjet ink should be small enough to allow the ink to flow freely through the inkjet printing device, especially at the jetting nozzles. It is also desirable to use small particles to obtain maximum color strength and slow down sedimentation.

[0146] The average particle size of the pigment in the pigmented inkjet ink should preferably be between 0.05 μm and 1 μm. Preferably, the average pigment particle size is between 0.05 μm and 0.5 μm, more preferably between 0.08 μm and 0.3 μm, particularly preferably between 0.1 μm and 0.2 μm, and most preferably between 0.1 μm and 0.15 μm.

[0147] The pigment is used in the inkjet ink in an amount of 0.1 wt % to 20 wt %, preferably 1 wt % to 10 wt %, and most preferably 2 wt % to 6 wt %, based on the total weight of the pigmented inkjet ink. A pigment concentration of at least 2 wt % is preferred to reduce the amount of inkjet ink required to produce a colored pattern, while a pigment concentration above 5 wt % reduces the color gamut of a colored pattern printed with a print head having a nozzle diameter of 20 μm to 50 μm.

[0148] A white pigmented free radical curable inkjet ink may be included in the ink set when the pigmented free radical inkjet ink is printed on a thermoplastic foil or substrate that is not white enough.

[0149] The white inkjet ink preferably comprises a pigment with a high refractive index, preferably greater than 1.60, preferably greater than 2.00, more preferably greater than 2.50 and most preferably greater than 2.60. Such white pigments generally have a very high hiding power, i.e. a limited amount of white ink is required to mask the color and defects of the core layer. The most preferred white pigment is titanium dioxide.

[0150] The white inkjet ink preferably contains the white pigment in an amount of 8 to 30 wt %, more preferably 12 to 25 wt %, based on the total weight of the white inkjet ink.

[0151] The number average particle diameter of the white pigment is preferably 150nm to 500nm, and most preferably 180nm to 300nm. When the average diameter is less than 150nm, sufficient hiding power cannot be obtained, and when the average diameter exceeds 500nm, the storage capacity and ejection adaptability of the ink tend to decrease.

[0152] The number average particle size is best determined by photon correlation spectroscopy at a wavelength of 633 nm using a 4 mW HeNe laser on a diluted sample of the pigmented inkjet ink. A suitable particle size analyzer for use is the Malvern Spectroscopy® obtained from Goffin-Meyvis TM nano-S. For example, a sample can be prepared by adding one drop of ink to a cuvette containing 1.5 mL of ethyl acetate and mixing until a homogenous sample is obtained. The measured particle size is the average of 3 consecutive measurements consisting of 6 20 second runs.

[0153] Dispersants

[0154] The pigmented free radical curable inkjet ink contains a dispersant to further improve the pigment dispersion properties. The dispersant is preferably a polymeric dispersant. Such dispersants improve the reliability of the inkjet printing process due to the generally lower sedimentation velocity, especially when they contain secondary or tertiary amine groups.

[0155] Typical polymer dispersants are copolymers of two monomers, but they can contain three, four, five or even more monomers. The properties of polymer dispersants depend on both the nature of the monomers and their distribution in the polymer. Copolymer dispersants preferably have the following polymer composition:

[0156] Statistically polymerized monomers (e.g., monomers A and B polymerize to form ABBAABAB);

[0157] Alternating monomers (e.g., monomers A and B polymerize to form ABABABAB);

[0158] Gradient polymerization of monomers (e.g., monomers A and B polymerize to form AAABAABBABBB);

[0159] Block copolymers (e.g., monomers A and B polymerized to AAAAABBBBBB), where the block length of each block (2, 3, 4, 5 or more) is important to the dispersing ability of the polymeric dispersant;

[0160] Graft copolymers (graft copolymers consist of a polymer backbone and polymer side chains attached to the backbone); and

[0161] • Mixed forms of these polymers, such as block gradient copolymers.

[0162] The polymeric dispersants preferably have a number average molecular weight Mn between 500 and 30,000, more preferably between 1,500 and 10,000.

[0163] The polymeric dispersant preferably has a weight average molecular weight Mw of less than 100,000, more preferably less than 50,000 and most preferably less than 30,000.

[0164] The polymeric dispersant preferably has a polydispersity index PD of less than 2, more preferably less than 1.75 and most preferably less than 1.5.

[0165] Commercial examples of polymeric dispersants are as follows:

[0166] ·DISPERBYK TM Dispersants, obtained from BYK CHEMIE GMBH;

[0167] ·SOLSPERSE TM Dispersants, obtained from LUBRIZOL;

[0168] TEGO TM DISPERS TM Dispersant, obtained from EVONIK;

[0169] ·EDAPLAN TM Dispersant, obtained from CHEMIE;

[0170] ETHACRYL TM Dispersant, obtained from LYONDELL;

[0171] ·GANEX TM Dispersant, obtained from ISP;

[0172] ·DISPEX TM and EFKA TM Dispersant, obtained from BASF;

[0173] ·DISPONER TMDispersant from DEUCHEM.

[0174] Particularly preferred polymeric dispersants include Solsperse from LUBRIZOL TM Dispersant, Efka from BASF TM Dispersant, Disperbyk from BYK CHEMIE GMBH TM Dispersant and Ajisper from AJINOMOTO FINE-TECHNOCo TM Dispersant. A particularly preferred dispersant is Solsperse from LUBRIZOL. TM BYK CHEMIE GMBH TM 162.

[0175] The dispersants may be used alone or in combination of two or more thereof.

[0176] The polymeric dispersant is preferably used in an amount of 2 to 600 wt %, more preferably 5 to 200 wt %, most preferably 50 to 90 wt %, based on the weight of the pigment.

[0177] Dispersion enhancer

[0178] Dispersion synergists generally consist of an anionic part and a cationic part. The anionic part of the dispersion synergist exhibits a certain molecular similarity with the color pigment, and the cationic part of the dispersion synergist consists of one or more protons and / or cations to compensate for the charge of the anionic part of the dispersion synergist.

[0179] The dispersion synergist is preferably added in a smaller amount than the polymeric dispersant. The ratio of polymeric dispersant / dispersion synergist depends on the pigment and should be determined experimentally. Typically, the ratio of the weight % of polymeric dispersant to the weight % of dispersion synergist is selected between 2:1 and 100:1, preferably between 2:1 and 20:1.

[0180] Suitable commercially available dispersion enhancers include Solsperse from LUBRIZOL TM 5000 and Solsperse TM 22000.

[0181] For the magenta ink used, particularly preferred pigments are diketopyrrolopyrrole pigments or quinacridone pigments. Suitable dispersion synergists include those disclosed in EP 1790698 A (AGFA GRAPHICS), EP 1790696 A (AGFA GRAPHICS), WO 2007 / 060255 (AGFA GRAPHICS) and EP 1790695 A (AGFA GRAPHICS).

[0182] In dispersing CI Pigment Blue 15:3, it is preferred to use a sulfonated copper phthalocyanine dispersion synergist, such as Solsperse from LUBRIZOL. TM 5000. Suitable dispersion synergists for yellow inkjet inks include those disclosed in EP 1790697 A (AGFA GRAPHICS).

[0183] Polymerizable compounds

[0184] The one or more pigmented free radical curable inkjet inks comprise a polymerizable composition containing 10 to 90 wt %, preferably 40 to 80 wt %, of one or more monofunctional polymerizable compounds, based on the total weight of the polymerizable composition.

[0185] Any monomer and oligomer capable of free radical polymerization can be used as the polymerizable compound. By changing the ratio between the monomer and the oligomer, the viscosity of the free radical curable inkjet ink can be adjusted. The polymerizable compound can be any monomer and / or oligomer found in Polymer Handbook Volume 1+2, 4th Edition, Wiley-Interscience, 1999, edited by J. BRANDRUP et al.

[0186] The polymerisable compounds used in the free radical curable liquids may also be suitably used in the pigmented free radical curable inkjet inks.

[0187] Photoinitiator system

[0188] If electron beam curing is not used to cure the free radical curable liquid or pigmented free radical curable inkjet ink, a photoinitiating system is used. The photoinitiating system contains at least one free radical photoinitiator, but preferably contains a combination of a photoinitiator and preferably also one or more co-initiators.

[0189] The photoinitiator in the free radical curable liquid and inkjet ink can be a Norrish Type I initiator or a Norrish Type II initiator. A Norrish Type I initiator is an initiator that cleaves upon excitation to immediately generate an initiating group. A Norrish Type II initiator is a photoinitiator that is activated by actinic radiation and forms free radicals by abstracting hydrogen from a second compound, which becomes the actual initiating free radical. This second compound is referred to as a polymerization synergist or coinitiator. Both Type I and Type II photoinitiators can be used in the present invention alone or in combination.

[0190] The photoinitiating system preferably comprises 4 to 20 wt % of free radical photoinitiator and co-initiator.

[0191] Norrish I type photoinitiator

[0192] Preferred Norrish Type I photoinitiators for use in the UV curable inkjet inks of the present invention are acylphosphine oxide and α-hydroxyketone photoinitiators.

[0193] Acylphosphine oxide photoinitiators are particularly advantageous for curability when UV curing is performed with UV LEDs having a long wavelength of greater than 360 nm, and are even more advantageous when the acylphosphine oxide photoinitiator is further combined with a Norrish type II photoinitiator containing a thioxanthone group.

[0194] Preferred examples of the acylphosphine oxide photoinitiator include, but are not particularly limited to, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, and bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide.

[0195] Preferred commercially available acylphosphine oxide photoinitiators include but are not specifically limited to Omnirad TM 819 (Bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide), Omnipol TM TP, Omnirad TM TPO (2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide), Omnirad TM TPO-L (ethyl (2,4,6-trimethylbenzoyl)phenylphosphinate), all available from IGM RESINS.

[0196] The content of the acylphosphine oxide photoinitiator is preferably 3 to 15 wt %, more preferably 5 to 13 wt %, and still more preferably 6 to 10 wt %, based on the total weight of the UV curable inkjet ink.

[0197] Examples of α-hydroxyketone photoinitiators include, but are not particularly limited to, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, and 1-[4-(2-hydroxyethoxy)-phenyl]2-hydroxy-2-methyl-1-propan-1-one.

[0198] Examples of commercial α-hydroxyketone photoinitiators include, but are not specifically limited to, Omnirad available from IGM RESINS M 1173、Omnirad TM 184 and Omnirad TM 127 and Omnirad TM 4817.

[0199] The content of the α-hydroxyketone is preferably 1 to 10 wt %, more preferably 2 to 8 wt %, and still more preferably 3 to 6 wt %, based on the total weight of the UV curable inkjet ink.

[0200] In a preferred embodiment, one or more acyl groups of the acylphosphine oxide photoinitiator or α-hydroxyketone photoinitiator are attached to a polymer or polymerizable group.

[0201] Suitable polymeric acylphosphine oxide photoinitiators are disclosed in EP 2960303 A (FUJFILM).

[0202] Examples of suitable polymeric α-hydroxyketone photoinitiators are available from IGM RESINS as Esacure TM KIP150 obtained.

[0203] Suitable polymerizable α-hydroxy ketone photoinitiators are disclosed in US 4922004 (MERCK), such as 4-(2-acryloyloxyethoxy)-phenyl 2-acryloyloxy-2-propyl ketone prepared in Example 3.

[0204] In a particularly preferred embodiment of the UV curable inkjet ink, the free radical photoinitiator comprises at least 4 wt%, preferably 5 wt% to 15 wt% of an acylphosphine oxide initiator, based on the total weight of the UV curable inkjet ink. In such an amount, good curability is obtained when UV curing is performed with a UV LED having a long wavelength of more than 360 nm.

[0205] Norrish II photoinitiator

[0206] The free radical curable liquid and inkjet ink may contain a Norrish II type photoinitiator comprising a photoinitiating moiety selected from a thioxanthone group and a benzophenone group. A Norrish II type photoinitiator containing a thioxanthone group is particularly preferred because it facilitates UV LED curing, especially for UV LEDs emitting a wavelength of at least 360 nm or even 370 nm.

[0207] However, free radical curable liquids and inkjet inks are preferably free of thioxanthone. The degradation products of thioxanthone after UV curing tend to impart an undesirable yellow tint to whites or an undesirable green tint to cyans.

[0208] Suitable examples of Norrish Type II photoinitiators containing a thioxanthone group include, but are not specifically limited to, thioxanthone; diethylthioxanthone, such as 2,4-diethylthioxanthone; isopropylthioxanthone, such as 2-isopropylthioxanthone and 4-isopropylthioxanthone; and chlorothioxanthone, such as 2-chlorothioxanthone.

[0209] A specific example of a commercially available Norrish II type photoinitiator containing a thioxanthone group is Speedcure TM DETX (2,4-diethylthioxanthone) and Speedcure TM ITX (2-isopropylthioxanthone), and Kayacure from Nippon Kayaku Co. TM DETX-S (2,4-diethylthioxanthone).

[0210] Suitable examples of Norrish II type photoinitiators containing a benzophenone group include, but are not specifically limited to, benzophenone; methyl benzophenone; methyl 2-benzoylbenzoate; phenyl benzophenone, such as 4-phenyl benzophenone; trimethyl benzophenone; bis(alkylamino)benzophenone; and 4-(dialkylamino)benzophenone.

[0211] A specific example of a commercially available Norrish II type photoinitiator containing a benzophenone group is Omnirad from IGMRESINS TM 4MBZ and Omnirad TM BP, Speedcure from LAMBSON TM PBZ and Speedcure TM 5040. The latter is a mixture of benzophenone and thioxanthone.

[0212] The content of the Norrish Type II photoinitiator comprising a photoinitiating moiety selected from a thioxanthone group and a benzophenone group is preferably from 0.5 wt% to 7.5 wt%, more preferably from 1 wt% to 5 wt%, based on the total weight of the UV curable inkjet ink. However, if the Norrish Type II photoinitiator is a polymerizable or polymeric thioxanthone compound, its content may be higher, preferably up to 25 wt%, more preferably up to 15 wt%, based on the total weight of the UV curable inkjet ink.

[0213] Preferred examples of polymerizable Norrish type II photoinitiators comprising a photoinitiating moiety selected from a thioxanthone group or a benzophenone group are disclosed in EP 2161264 A (AGFA), EP 2199273 A (AGFA) and EP 2684876 A (AGFA).

[0214] Preferred examples of polymeric Norrish type II photoinitiators comprising a photoinitiating moiety selected from a thioxanthone group or a benzophenone group are disclosed in EP 1616920 A (AGFA) and EP 1616899 A (AGFA).

[0215] Commercial examples of polymeric thioxanthones and benzophenones include Omnipol from IGM RESINS TM BP, Omnipol TM TX and Omnipol TM 2702.

[0216] Coinitiator

[0217] To further increase the photosensitivity, the UV curable inkjet ink may additionally contain a coinitiator, also called a polymerization synergist, for which amine synergists are usually used.

[0218] Suitable examples of amine synergists can be divided into three categories: 1) aliphatic tertiary amines, such as methyldiethanolamine, dimethylethanolamine, triethanolamine, triethylamine and N-methylmorpholine;

[0219] (2) aromatic amines such as amyl p-dimethylaminobenzoate, 2-n-butoxyethyl 4-(dimethylamino)benzoate, 2-(dimethylamino)ethyl benzoate, ethyl 4-(dimethylamino)benzoate, and 2-ethylhexyl 4-(dimethylamino)benzoate; and

[0220] (3) (Meth)acrylated amines, such as dialkylaminoalkyl (meth)acrylates (eg, diethylaminoethyl acrylate) or N-morpholinoalkyl (meth)acrylates (eg, N-morpholinoethyl acrylate).

[0221] The UV curable inkjet ink preferably comprises a tertiary amine co-initiator, preferably a polymerizable or polymeric tertiary amine co-initiator.

[0222] Preferred diffusion hindered co-initiators are the polymerizable co-initiators disclosed in paragraphs

[0088] and

[0097] of EP 2053101 A (AGFA).

[0223] Preferred diffusion hindered co-initiators include polymeric co-initiators having a dendritic polymeric structure, more preferably a hyperbranched polymeric structure. Preferred hyperbranched polymeric co-initiators are those disclosed in US 2006014848 A (AGFA).

[0224] The UV curable inkjet ink preferably comprises the (diffusion hindered) co-initiator in an amount of 0.1 to 15 wt%, more preferably in an amount of 0.5 to 10 wt%, most preferably in an amount of 1 to 8 wt%, based on the total weight of the inkjet ink.

[0225] Polymerization inhibitors

[0226] The free radical curable liquids and inkjet inks may also contain a polymerization inhibitor. Due to the fact that the ink contains a polymerization inhibitor, polymerization reactions prior to curing, for example during storage or transport, may be prevented.

[0227] Suitable polymerization inhibitors include phenolic antioxidants, hindered amine light stabilizers, phosphor-type antioxidants, benzoquinone, hydroquinone and derivatives such as hydroquinone monomethyl ether which is commonly used in (meth)acrylate monomers.

[0228] Examples of phenolic polymerization inhibitors include, but are not limited to, the following: p-methoxyphenol, cresol, tert-butylcatechol, di-tert-butyl-p-cresol, hydroquinone monomethyl ether, α-naphthol, 3,5-di-tert-butyl-4-hydroxytoluene, 2,6-di-tert-butyl-4-methylphenol, 2,2'-methylene-bis(4-methyl-6-tert-butylphenol), 2,2'-methylene-bis(4-ethyl-6-butylphenol) and 4,4'-thio-bis(3-methyl-6-tert-butylphenol) and pyrogallol.

[0229] Suitable commercial inhibitors are, for example, Sumilizer TM GA-80, Sumilizer TM GM and Sumilizer TM GS, manufactured by Sumitomo Chemical Co. Ltd.; Genorad TM 16. Genorad TM 18 and Genorad TM 20, obtained from Rahn AG; IrgastabTM UV10 and Irgastab TM UV22, Tinuvin TM 460 and CGS20, obtained from Ciba Specialty Chemicals; Floorstab TM UV series (UV-1, UV-2, UV-5 and UV-8) from Kromachemltd; Additol TM S series (S100, S110, S120 and S130) from ALLNEX.

[0230] A preferred polymerization inhibitor is Irgastab available from BASF TM UV 10. Other examples of polymerization inhibitors include TEMPO, TEMPOL, and AI cupferron.

[0231] The polymerization inhibitor may be used alone or in combination of two or more thereof.

[0232] In a preferred embodiment, the polymerization inhibitor is a mixture of different types of polymerization inhibitors. Preferred polymerization inhibitors are mixtures of oxyl radical-based polymerization inhibitors, phenol-based polymerization inhibitors and amine-based polymerization inhibitors. Suitable examples are given in EP 2851402 A (FUJIFILM).

[0233] The polymerization inhibitor is preferably present in an amount of 200 to 20,000 ppm relative to the total amount of the inkjet ink. Below 200 ppm, undesired polymerization is not sufficiently inhibited, while above 20,000 ppm, the curing speed is severely reduced.

[0234] Surfactants

[0235] The free radical curable liquids and inkjet inks may contain a surfactant. The surfactant may be anionic, cationic, nonionic or zwitterionic.

[0236] In the free radical curable liquid, the surfactant is preferably present in an amount not exceeding 0.3 wt%, more preferably 0 wt% to 0.2 wt%, based on the total weight of the free radical curable liquid. At higher concentrations, adhesion deteriorates rapidly.

[0237] In the pigmented free radical curable inkjet ink, the total amount of surfactant is preferably less than 3 wt% based on the total weight of the ink, and more preferably less than 1.5 wt% in total based on the total weight of the free radical curable inkjet ink to prevent foaming of the ink in its container. The surfactant content is preferably 0.05 wt% to 1.5 wt%, more preferably 0.10 wt% to 1.0 wt%, based on the total weight of the free radical curable inkjet ink.

[0238] Preferred surfactants are selected from fluorinated surfactants (such as fluorinated hydrocarbons) and silicone surfactants. The silicone surfactant is preferably a siloxane and may be alkoxylated, polyester-modified, polyether-modified, polyether-modified hydroxy-functional, amine-modified, epoxy-modified and other modifications or combinations thereof. Preferred siloxanes are polymers, such as polydimethylsiloxane.

[0239] Preferred commercially available silicone surfactants include BYK TM 333 and BYK TM UV3510 and Tegoglide from EVONIK TM 410.

[0240] In a preferred embodiment, the surfactant is a polymerizable compound.

[0241] Preferred polymerizable silicone surfactants include (meth)acrylated silicone surfactants. Most preferably, the (meth)acrylated silicone surfactant is an acrylated silicone surfactant, since acrylates are more reactive than methacrylates.

[0242] In a preferred embodiment, the (meth)acrylated silicone surfactant is a polyether-modified (meth)acrylated polydimethylsiloxane or a polyester-modified (meth)acrylated polydimethylsiloxane.

[0243] Preferred commercially available (meth)acrylated silicone surfactants include: Ebecryl silicone diacrylate TM 350, from ALLNEX; polyether-modified acrylated polydimethylsiloxane BYK TM UV3500, BYK TM UV3510 and BYK TM UV3530; Polyester modified acrylated polydimethylsiloxane BYK TM UV3570, all manufactured by BYK Chemie; Tego TM Rad 2100, Tego TM Rad 2200N, Tego TMRad2250N, Tego TM Rad 2300, Tego TM Rad2500, Tego TM Rad 2600, Tego TM Rad 2700 and Tego TM RC711, all manufactured by EVONIK. Another preferred silicone is Silwet from OSI SPECIALITIES BENELUX NV. TM L7500.

[0244] Obtained from EVONIK; Silaplane TM FM7711、Silaplane TM FM7721, Silaplane TM FM7731, Silaplane TM FM0711, Silaplane TM FM0721, Silaplane TM FM0725, Silaplane TM TM0701, Silaplane TM TM0701T, all manufactured by CHISSO Corporation; and DMS-R05, DMS-R11, DMS-R18, DMS-R22, DMS-R31, DMS-U21, DBE-U22, SIB1400, RMS-044, RMS-033, RMS-083, UMS-182, UMS-992, UCS-052, RTT-1011 and UTT-1012, all manufactured by GELEST Inc.

[0245] A particularly preferred surfactant for free radical curable liquids is available from SILTECH CORPORATION Surfactants, such as ACR Di-1508.

[0246] Preparation of free radical curable inkjet inks

[0247] The preparation of UV curable inkjet inks is well known to those skilled in the art. Preferred preparation methods are disclosed in paragraphs

[0076] to

[0085] of WO2011 / 069943 (AGFA).

[0248] The average particle size and distribution of the color pigments are important characteristics of inkjet inks.Inkjet inks can be prepared by precipitating or grinding the pigment in a dispersion medium in the presence of a dispersant.

[0249] Mixing equipment can include pressure kneaders, open kneaders, planetary mixers, dissolvers and Dalton universal mixers. Suitable grinding and dispersing equipment is a ball mill, a pearl mill, a colloid mill, a high-speed disperser, a double roller mill, a bead mill, a paint conditioner and a three-roll mill. Dispersions can also be prepared using ultrasonic energy.

[0250] Different types of materials can be used as grinding media, such as glass, ceramic, metal and plastic.In a preferred embodiment, the grinding media can comprise particles, preferably substantially spherical in shape, such as beads consisting essentially of a polymer resin or yttrium stabilized zirconia beads.

[0251] During the mixing, grinding and dispersing processes, each process is carried out under cooling to prevent heat accumulation and, as far as possible, under light conditions that substantially exclude actinic radiation.

[0252] Inkjet inks may contain more than one pigment and may be prepared using a separate dispersion for each pigment, or alternatively several pigments may be mixed and co-milled to prepare a dispersion.

[0253] The dispersion process can be carried out in continuous, batch or semi-batch mode.

[0254] The preferred amounts and ratios of the components of the millbase will vary depending on the specific materials and intended applications. The contents of the grinding mixture include the millbase and the grinding media. The millbase comprises a pigment, a polymer dispersant, and a liquid carrier. For inkjet inks, excluding the grinding media, the pigment is typically present in the millbase in an amount of 5 to 50 weight %. The weight ratio of the pigment to the polymer dispersant is preferably 20:1 to 1:2, more preferably 2:1 to 1:1.

[0255] The optimum grinding time may vary and depends on the pigment selected, mechanical means and dwelling conditions, initial and desired final particle size, etc. In the present invention, pigment dispersions having an average particle size of less than 100 nm can be prepared.

[0256] After grinding is complete, the grinding media is separated from the ground particulate product (in dry or liquid dispersion form) using conventional separation techniques, such as by filtration, screening through a screen, etc. Screens are typically built into a grinder, such as a bead mill. The ground pigment concentrate is preferably separated from the grinding media by filtration.

[0257] Typically, it is desirable to prepare inkjet inks in the form of concentrated pigment dispersions, which are then diluted to the appropriate concentration for use in an inkjet printing system. This technique allows larger quantities of pigmented inks to be prepared from the equipment. By dilution, the inkjet ink is adjusted to the desired viscosity, surface tension, color, hue, saturation density, and print area coverage for a particular application.

[0258] Decorative Laminate

[0259] A decorative laminate according to a preferred embodiment of the present invention comprises an inkjet printed decorative image printed with one or more pigmented free radical curable inkjet inks and an adhesive layer of a free radical curable liquid between a first thermoplastic foil and a second thermoplastic foil; wherein at least one of the first and second thermoplastic foils is a transparent thermoplastic foil; wherein the one or more pigmented free radical curable inkjet inks comprise a color pigment and a polymerizable composition, the polymerizable composition comprising 10 wt % to 90 wt % of one or more monofunctional polymerizable compounds; wherein the free radical curable liquid comprises a polymerizable composition, the polymerizable composition comprising 20 wt % or more of a multifunctional polymerizable compound and 15 wt % or more of a monofunctional polymerizable compound A or B; wherein all weight percentages wt % are based on the total weight of the polymerizable composition in the pigmented free radical curable inkjet ink or the free radical curable liquid; wherein the monofunctional polymerizable compound A is a compound according to formula (1):

[0260]

[0261] wherein R represents hydrogen or a methyl group; X represents oxygen or an NR'-group; L represents a divalent linking group having not more than 10 carbon atoms; R' is selected from hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted aralkyl, substituted or unsubstituted alkaryl and substituted or unsubstituted aryl or heteroaryl; n represents 0 or 1; and A represents a moiety according to formula (1A):

[0262]

[0263] wherein Q represents the atoms necessary to form a five- to eight-membered ring, and the dashed lines represent covalent bonds to carbon atoms;

[0264] Wherein the monofunctional polymerizable compound B is a compound according to formula (2):

[0265]

[0266] wherein R2 represents hydrogen or methyl; L represents a divalent linking group having not more than 10 carbon atoms; n represents 0 or 1; and D represents a five- to seven-membered saturated heterocyclic ring containing a single ether group.

[0267] In a particularly preferred embodiment of the decorative laminate, the first and second thermoplastic foils comprise polyvinyl chloride.Such thermoplastic sheets have excellent water resistance and achieve excellent adhesion using pigmented free radical curable inkjet inks and free radical curable liquids.

[0268] The decorative panels preferably have tongues and grooves for similar glueless interlocking decorative panels. By shaping the tongues and grooves in a particular way, only Figure 1 As shown in the example of , the decorative panels can "bite" into each other. The polymerizable composition of the pigmented free radical curable inkjet ink and the free radical curable liquid allows such shaping without showing cracks in the image.

[0269] In inkjet printing, a CMYK inkjet ink set is commonly used. It was found that when the magenta inkjet ink was replaced by a red inkjet ink, wood decorative images, which are often used for floor laminates, could be reproduced more accurately without suffering from metamerism. Good adhesion to the red ink was achieved when the pigment was selected from the following pigments: CI Pigment Red 122, CI Pigment Red 176, CI Pigment Red 188, CI Pigment Red 207, CI Pigment Red 242, CI Pigment Red 254, CI Pigment Red 272 and mixed crystals thereof.

[0270] Decorative layer

[0271] The decorative layer comprises a colored pattern printed with a pigmented free radical curable inkjet ink and an adhesive layer to which a free radical curable liquid is applied. The decorative layer is applied to a thermoplastic foil (see Figure 1 .A and Figure 1 .B), or alternatively it may be applied directly to the substrate (see Figure 1 .C and Figure 1 .D).

[0272] There is no practical limit to the content of the colored image. The colored image may also contain information, such as text, arrows, logos, etc. In contrast to gravure printing, the advantage of inkjet printing is that such information can be printed in low volumes without additional cost.

[0273] In a preferred embodiment, the colored image is a wood replica or a stone replica, but it can also be a fantasy or creative image, such as an ancient world map or a geometric pattern, or even a single color, used to make, for example, a floor composed of black tiles and red tiles or a single color furniture door.

[0274] The advantage of printing wood color images is that, in addition to oak, pine and beech, very expensive woods such as black walnut, which are usually not used for house decoration, can also be simulated.

[0275] The advantage of printing a stone coloured image is that a floor can be produced which is an exact imitation of a stone floor but which does not feel cold when walked on barefoot and which can easily be changed over time according to fashion.

[0276] Protective layer

[0277] The top surface of the decorative panel is usually a transparent thermoplastic foil ( Figure 2 11) However, an additional finishing layer may be applied on the protective layer.

[0278] In a preferred embodiment, an antistatic layer is applied over the protective layer.Techniques for rendering decorative laminates antistatic are well known in the field of decorative laminates, as exemplified by EP 1567334 A (FLOORING IND).

[0279] In a particularly preferred embodiment, the decorative panel has a polyurethane facing layer on the protective layer.

[0280] The top surface of the decorative panel (i.e. at least the protective layer) is preferably provided with a relief matching the colored pattern, for example, wood grain, cracks and knots in a wood print. The embossing technology to achieve such a relief is well known in the flooring field, for example, disclosed in EP 1290290 A (FLOORING IND), US 2006144004 (UNILIN), EP 1711353 A (FLOORING IND) and US 2010192793 (FLOORING IND).

[0281] Most preferably, the relief is formed by pressing a digital embossing plate against a transparent thermoplastic foil forming a protective layer during hot pressing. A digital embossing plate is a plate comprising ridges which can be used to form a relief on a decorative panel by pressing the digital embossing plate against the protective layer of the decorative panel. The plate is preferably rigid by using metal or hard plastic.

[0282] An alternative to the digital embossing plate may be a digital embossing roller, which is a roller comprising ridges to form a relief on the decorative panel. The relief is applied to the protective layer of the decorative panel by pressing the digital embossing roller against it and rotating, preferably using heat.

[0283] The facing layer, preferably a polyurethane facing layer, may include hard particles, such as corundum, to prevent scratching of the top surface. The total amount of hard particles is preferably 1 g / m 2 With 100g / m2 Between, preferably 2g / m 2 Up to 50g / m 2 .

[0284] Preferred hard particles are ceramic or mineral particles selected from aluminum oxide, silicon carbide, silicon oxide, silicon nitride, tungsten carbide, boron carbide and titanium dioxide or selected from any other metal oxide, metal carbide, metal nitride or metal carbonitride. The most preferred hard particles are corundum and so-called Sialon ceramics. In principle, various particles can be used. Of course, any mixture of the above hard particles can also be applied.

[0285] The amount of hard particles can be determined according to the desired scratch resistance.

[0286] Preferably, hard particles with an average particle size between 1 μm and 200 μm are applied over the printed pattern at 1 g / m 2 With 40g / m 2 The amount of such particles is between 20g / m 2 The quantity can satisfy lower quality.

[0287] The transparent thermoplastic foil used as protective layer preferably has a thickness of more than 100 μm, more preferably 300 μm to 700 μm. The thermoplastic foil is transparent so that the colored pattern of the decorative layer can be observed.

[0288] Grassroots

[0289] In a preferred embodiment, the decorative panel comprises a base layer. The base layer provides the decorative panel with sufficient rigidity so that when, for example, a long rectangular decorative panel bends under its own weight, the panel does not break. To this end, the base layer is preferably reinforced with fibers.

[0290] In a preferred embodiment, the base layer comprises essentially polyvinyl chloride and reinforcing fibers. More preferably, the base layer comprises essentially polyvinyl chloride and glass fibers.

[0291] The base layer may consist of two foils with glass fiber wool interposed.

[0292] The base layer may contain minerals. Particularly suitable in this context are talc or calcium carbonate (chalk), aluminum oxide, silicon dioxide. The base layer may contain flame retardants.

[0293] In a particularly preferred embodiment, the base layer is a plasticized PVC film which contains 10% to 50% by weight of filler material, preferably predominantly calcium carbonate; and / or 2% to 20% by weight, preferably 10% to 20% by weight, of titanium dioxide; and / or 2% to 20% by weight, preferably between 10% to 20% by weight, of a softening polymer, in particular PLA, PMMA or PVAC.

[0294] The substrate may also be a so-called wood plastic composite (WPC), preferably containing one or more polymers or copolymers selected from the group consisting of polypropylene, polyethylene and polyvinyl chloride.

[0295] When the base layer comprises one or more polymers or copolymers selected from polypropylene, polyethylene and polyvinyl chloride, then the base layer may be considered to represent one of the first and second thermoplastic foils in the manufacturing method and decorative laminate of the present invention.

[0296] Inkjet printing device

[0297] Free radically curable inkjet inks and free radically curable liquids may be ejected by one or more printheads that eject small droplets of ink through nozzles in a controlled manner onto an ink receiving surface that moves relative to the printheads.

[0298] The preferred printhead for inkjet printing system is a piezoelectric head. Piezoelectric inkjet printing is based on the movement of a piezoelectric ceramic converter when a voltage is applied. The applied voltage changes the shape of the piezoelectric ceramic converter in the printhead, thereby creating a gap, which is then filled with ink. When the voltage is removed again, the ceramic expands to its original shape, ejecting ink drops from the printhead. However, the inkjet printhead used in the present invention is not limited to a piezoelectric inkjet printhead. Other inkjet printheads can be used and include various types, such as continuous, electrostatic and acoustic drop-on-demand ink types.

[0299] A preferred piezo print head is a so-called push mode type piezo print head having a relatively large piezo element which is also capable of ejecting more viscous inkjet drops. Such a print head is available from RICOH as a GEN5s print head.

[0300] In a preferred embodiment, the piezoelectric print head is a so-called through-flow piezoelectric drop-on-demand inkjet print head. Such a print head is available from TOSHIBA TEC as a CFlou print head. Through-flow print heads are preferred because they improve the reliability of inkjet printing, which is important in an industrial environment.

[0301] In a preferred embodiment, use multi-pass inkjet printing device to carry out inkjet printing.In such device, inkjet printing head scans back and forth across the mobile ink receiving surface in the lateral direction.In order to obtain high area throughput, preferably bidirectional printing.The free radical curable inkjet ink of coloring and free radical curable liquid can be printed in parallel printing mode or with 2-step printing mode.In parallel printing mode, free radical curable inkjet ink and free radical curable liquid are sprayed and solidified simultaneously, and in 2-step printing mode, free radical curable inkjet ink is first sprayed and solidified, and only after free radical curable inkjet ink is solidified, free radical curable liquid is sprayed on the free radical curable inkjet ink of solidified coloring and solidified.

[0302] The parallel printing mode has an advantage in productivity, but is slightly inferior to the 2-step printing mode in adhesion. When excellent adhesion results are required, the 2-step printing mode is preferably used.

[0303] In another preferred embodiment, the pigmented free radical curable inkjet ink is printed in a so-called "single pass printing process", which can be performed by using a page-wide inkjet print head or a plurality of staggered inkjet print heads covering the entire width of the ink-receiving surface. In a single pass printing process, the inkjet print head generally remains stationary and the ink-receiving surface is transported under the inkjet print head.

[0304] The dimensions of decorative laminates usually have a width of more than 2 m, which drives up the costs of single-pass inkjet printers, since for each color a large number of print heads must be foreseen covering the entire width of the ink-receiving surface.

[0305] Therefore, in a preferred embodiment of a single-pass printing process, the free radical curable liquid is not applied by spraying with a print head, but is applied using a cheaper coating technique or printing technique. Preferred coating techniques for applying the free radical curable liquid are selected from spraying, knife coating, extrusion coating, slide hopper coating and curtain coating. Preferred printing techniques for applying the free radical curable liquid are selected from flexographic printing, gravure printing and offset printing.

[0306] In another preferred embodiment of multi-pass inkjet printing, the radically curable inkjet ink is printed with a multi-pass inkjet device, and the radically curable liquid is applied by a coating technique or a printing technique. The same coating technique and printing technique mentioned for the single-pass printing process are preferably used in combination with a multi-pass inkjet device.

[0307] In a most preferred embodiment, inkjet printing of free radical curable inkjet inks, especially UV curable inkjet inks, is carried out in a multi-pass printing mode. Multi-pass printing is a technique for reducing banding in inkjet printing. When ink dots are still in liquid form, they tend to flow together due to surface tension. This is called coalescence. In order to print high-quality images, it is important to print single dots. But in order to achieve full saturation color, the dots must overlap to completely cover the substrate. Coalescence can be avoided to a large extent by printing only a portion of the image data to avoid printing adjacent dots simultaneously during each printing cycle. In addition, by avoiding all horizontal adjacent portions, the lateral speed of the printing mechanism can be increased to twice the rated printing speed of the print head. In a preferred embodiment, the number of passes used is 2 to 6, more preferably no more than 4.

[0308] Another advantage of using a multi-pass printing mode is that UV curable inkjet inks are cured in a continuous pass rather than in a single pass, which would require a curing device with a high UV output. The print head life is also longer with multi-pass printing. While in single-pass printing, one side shooter is sufficient to replace the entire print head, in multi-pass printing, multiple side shooters can be tolerated and even failures can be tolerated. In addition, the cost of a multi-pass printer for printing wide format substrates is generally much lower than a single-pass inkjet device.

[0309] Curing device

[0310] Free radical curable inkjet inks and liquids are cured by actinic radiation.

[0311] In one embodiment, the actinic radiation is provided by an electron beam device.One advantage of electron beam curing is that no photoinitiating system is required to be present in free radical curable inkjet inks and liquids, making manufacturing more economical once the investment in electron beam curing has been made.

[0312] The preferred electron beam device is a low energy electron beam source that applies a dose of no more than 100 keV, preferably 50 to 80 keV, and preferably uses 1 to 5 mm of lead or 15 to 25 mm of stainless steel as shielding material. Most preferably, about 3 mm of lead or about 20 mm of stainless steel.

[0313] In another more preferred embodiment, the actinic radiation is provided by a UV curing device.

[0314] In multi-pass inkjet printing, the curing device may be arranged in combination with the print head of the inkjet printer, moving therewith, so as to expose the free radical curable composition to UV curing radiation soon after jetting.

[0315] Any UV light source, as long as a portion of the emitted light can be absorbed by the photoinitiator system, can be used as a radiation source, such as high-pressure or low-pressure mercury lamps, cold cathode tubes, black lights, UV LEDs, UV lasers and flashes. Among them, preferred sources are those that exhibit a relatively long wavelength UV contribution with a dominant wavelength of 300-400 nm. In particular, UV-A light sources are preferred due to their reduced light scattering leading to more efficient internal curing.

[0316] UV radiation is usually classified as UV-A, UV-B and UV-C as follows:

[0317] UV-A: 400nm to 320nm

[0318] UV-B: 320nm to 290nm

[0319] UV-C: 290nm to 100nm.

[0320] Most preferably, UV curing is performed using UVLEDs with a spectral emission between 345-420nm, more preferably between 360nm and 400nm. The latter UV LEDs have a very long life without reducing light output, which is common in mercury lamps. The use of these UV LED sources also enhances the reliability of inkjet printing in industrial environments.

[0321] To facilitate UV curing, the inkjet printer may include one or more oxygen depletion units. To reduce the oxygen concentration in the curing environment, the oxygen depletion unit arranges a layer of nitrogen or other relatively inert gas (e.g., CO2) with an adjustable position and adjustable inert gas concentration. Residual oxygen levels are preferably kept as low as 200 ppm, but may be in the range of 200 ppm to 1200 ppm.

[0322] Example

[0323] Material

[0324] Unless otherwise stated, all materials used in the following examples were obtained from standard sources such as Sigma-Aldrich (Belgium) and Acros (Belgium).

[0325] PB15:4 is the abbreviation used for CI Pigment Blue 15:4 pigment, available from CLARIANT BlueP-BFS is obtained.

[0326] S35000 is for SOLSPERSE TM Abbreviation for 35000, which is a polyethyleneimine-polyester hyperdispersant from LUBRIZOL.

[0327] DB162 is used as polymer dispersant 162, available from BYK CHEMIE GMBH, from which the solvent mixture of 2-methoxy-1-methylethyl acetate, xylene and n-butyl acetate has been removed. The polymer dispersant is a polyester-polyurethane dispersant based on caprolactone and toluene diisocyanate, with an amine value of 13 mg KOH / g, an Mn of about 4,425, and an Mw of about 6,270.

[0328] EFKA is a polyacrylate dispersant available from BASF as 7701 obtained.

[0329] PCA-2 is N-vinyl caprolactam available from BASF BELGIUM, NV.

[0330] PCA-6 was prepared as described in Preparation Example 1 on pages 21-22 of WO 2018 / 146259 (BASF).

[0331] PCB-1 is tetrahydrofurfuryl acrylate, available from ARKEMA as SR285 obtained.

[0332] CE-1 is (3-ethyl-3-oxetanyl)methacrylate, available from KOWA EUROPE GMBH as OXE-10.

[0333] IBOA is isobornyl acrylate, available from ARKEMA as SR506D obtained.

[0334] IDA is isodecyl acrylate, available from SARTOMER as SR395 obtained.

[0335] PEA is 2-phenoxyethyl acrylate, available from ARKEMA as SR339C was obtained.

[0336] CTFA is cyclic trimethylolpropane formal acrylate, available from ARKEMA as SR531 obtained.

[0337] SR504D is an ethoxylated nonylphenol acrylate available from ARKEMA as SR506D obtained.

[0338] TBCH is 4-tert-butylcyclohexyl acrylate, available from ARKEMA under the trade name CD217 was obtained.

[0339] ACMO is acryloylmorpholine, available from RAHN.

[0340] SR833S is tricyclodecane dimethanol diacrylate, available from ARKEMA as SR833s obtained.

[0341] DPGDA is dipropylene glycol diacrylate, available from BASF as DPGDA was obtained.

[0342] HDDA is 1,6-hexanediol diacrylate, available from ARKEMA as SR238 obtained.

[0343] VEEA is 2-(2'-vinyloxyethoxy)ethyl acrylate, a difunctional monomer available from NIPPONSHOKUBAI, Japan.

[0344] MPDA is 3-methyl-1,6-pentanediyl diacrylate, available from ARKEMA as SR341 obtained.

[0345] TMPTA is trimethylolpropane triacrylate, available from ARKEMA as SR351 obtained.

[0346] SR9035 is an ethoxylated (15) trimethylolpropane triacrylate containing fifteen ethoxy units, with a molecular weight of 956, and is available from SARTOMER as SR9035 obtained.

[0347] G4215 is an aliphatic polyester urethane acrylate available from RAHN as 4215 obtained.

[0348] G1122 is a monofunctional urethane acrylate available from RAHN as 1122 obtained.

[0349] CN963B80 is a urethane diacrylate available from ARKEMA as Obtained from CN963B80.

[0350] CN3755 is a diacrylated co-initiator available from ARKEMA as CN3755 was obtained.

[0351] CN3715 is the diethylamine Michael adduct of ethoxylated trimethylolpropane triacrylate, a coinitiator available from ARKEMA as CN3715 was obtained.

[0352] TPO is 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, produced by IGM RESINS TPO obtained.

[0353] TPO-L is an acylphosphine oxide photoinitiator, available from IGM RESINS. TPO-L was obtained.

[0354] BAPO is a bisacylphosphine oxide photoinitiator, available from IGM RESINS 819 obtained.

[0355] ITX is a mixture of isomers of 2-isopropylthioxanthone and 4-isopropylthioxanthone, obtained from IGM RESINS. ITX obtained.

[0356] BP acquires Omnirad from IGM RESINS TM BP obtained.

[0357] DETX is a thioxanthone photoinitiator available from RAHN as DETX obtained.

[0358] EPD is ethyl 4-dimethylaminobenzoate, available from RAHN AG as EPD obtained.

[0359] EHA is 2-ethylhexyl 4-dimethylaminobenzoate, available from RAHN as EHA obtained.

[0360] INHIB is formed according to Table 4 A mixture of polymerization inhibitors consisting of the following:

[0361] Table 4

[0362] Components weight% DPGDA 82.4 p-Methoxyphenol 4.0 BHT 10.0 <![CDATA[Cupferron TM AL]]> 3.6

[0363] BHT is the abbreviation of 2,6-di-tert-butyl-4-methylphenol (CASRN 128-37-0), which is obtained from ALDRICH CHEMICAL CO.

[0364] AL is aluminum N-nitrosophenylhydroxylamine, obtained from WAKO CHEMICALS LTD.

[0365] UV10 is 4-hydroxy-2,2,6,6-tetramethylpiperidinyloxy sebacate, available from BASF as UV10 obtained.

[0366] UV3510 is a polyether-modified polydimethylsiloxane wetting agent available from BYK CHEMIE GMBH as BYK TM UV3510 obtained.

[0367] T410 is a surfactant available from EVONIK as Tegoglide TM 410 obtained.

[0368] L7500 is a silicone surfactant available from MOMENTIVE PERFORMANCES L7500 obtained.

[0369] SILMER is a difunctional silicone acrylate prepolymer available from SILTECH CORPORATION as ACR Di-1508 obtained.

[0370] SILWAX is a polysiloxane surfactant available from SILTECH CORPORATION as B116 obtained.

[0371] P2 is an opaque white polyvinyl chloride foil 80 μm thick.

[0372] C3 is a 500 μm thick transparent polyvinyl chloride foil.

[0373] Measurement method

[0374] 1. Adhesion

[0375] Adhesion was determined by testing the peel strength. The test used 180° geometry and followed the EN431:1994 standard and was performed using The tensile machine was used. The tensile machine pulled the sample at a constant speed of 100 mm / min, and the force required to peel the sample at this speed was plotted as a function of distance. The results obtained were the average load / width between 10 mm and 80 mm. The results were reported in N / 5 cm.

[0376] Good adhesion requires a peel strength of at least 50 N / 5 cm. However, commercially superior products are required to exhibit adhesion of at least 60 N / 5 cm or even 70 N / 5 cm.

[0377] 2. Viscosity

[0378] The HAAKE Rotovisco 1 rotational rheometer was used at 45 °C and 1000 s -1 The viscosity of the sample was measured at a shear rate of 1.

[0379] 3. Adhesion

[0380] The samples were tested for adhesion by rubbing a clean cotton swab across the surface after curing.

[0381] According to whether there are traces left by the cotton swab, Table 5 Adhesion was evaluated.

[0382] Table 5

[0383]

[0384] Example 1

[0385] This example illustrates the effect of the amount of monofunctional polymerizable compound A or B in a free radical curable liquid polymerizable composition on adhesion.

[0386] Preparation of cyan pigment dispersion

[0387] Use DISPERLUX from DISPERLUX SARL, Luxembourg TM Disperser, by mixing according to Table 6 The cyan pigment dispersion was prepared by mixing the components of 1% cyan pigment for 30 minutes. The dispersion was then ground using a Bachofen DYNOMILL ECM grinder filled with 0.4 mm yttrium-stabilized zirconium oxide beads ("High Abrasion Resistant Zirconia Grinding Media" from TOSOH Co.). The mixture was circulated on the grinder for 2 hours. After grinding, the pigment dispersion was discharged into a vessel through a 1 μm filter.

[0388] Table 6

[0389] Components weight% PB15:4 16.00 S35000 16.00 INHIB 1.00 DPGDA 67.00

[0390] Preparation of free radical curable inkjet ink C-1

[0391] By mixing the cyan pigment dispersion and according to Table 7 Cyan free radical UV curable inkjet ink C-1 was prepared with the following components. The weight percentages are based on the total weight of the inkjet ink.

[0392] Table 7

[0393] Weight % of compound: Ink C-1 PB15:4 2.50 S35000 2.50 PCA-2 9.22 PCB-1 13.15 IBOA 17.65 PEA 13.04 IDA 4.66 DPGDA 15.62 CN963B80 5.30 CN3755 7.50 TPO 2.95 BAPO 2.25 ITX 2.00 INHIB 0.31 UV10 0.35 L7500 1.00

[0394] The polymerizable composition of the cyan free radical UV curable inkjet ink C-1 contained 67 wt% of the monofunctional polymerizable compound, based on the total weight of the inkjet ink.

[0395] Preparation of free radical curable liquids L-1 to L-8

[0396] By mixing Table 8The free radical curable liquids L-1 to L-8 were prepared with the components of . The amounts of all compounds are expressed as weight percentages based on the total weight of the free radical curable liquid.

[0397] Table 8

[0398]

[0399] Manufacturing of laminated materials

[0400] The cyan free radical curable inkjet ink C-1 was applied to the matte side of the thermoplastic foil P2 at a thickness of 10 μm and cured using a Fusion DRSE-120 conveyor belt equipped with a 12 W 395 nm LED at a speed of 20 m / min. The maximum output of the lamp was 1.05 J / cm 2 , and the peak intensity is 5.6 W / cm 2 .

[0401] Each free radical curable liquid L-1 to L-8 was then coated at a thickness of 10 μm on the thermoplastic foil P2 provided with curing ink C-1 and cured at a speed of 20 m / min using a Fusion DRSE-120 conveyor belt equipped with a 12 W 395 nm LED.

[0402] Then, each of the thermoplastic foils P2 provided with the cured ink C-1 and the cured free radical curable liquid was combined with a transparent thermoplastic foil C3 by making the ink layer on the foil P2 face the transparent thermoplastic foil C3. As another comparison, the thermoplastic foil P2 provided with the cured ink C-1 but without any cured free radical curable liquid was combined with a transparent thermoplastic foil C3 by making the ink layer on the foil P2 face the transparent thermoplastic foil C3. The assembly of foils P2 and C3 was then hot pressed for 160 seconds at a temperature of 160° C. and a pressure of 14 bar in an OLAH6 laminator from OASYS.

[0403] Evaluation and Results

[0404] The adhesiveness (peel strength) of the hot pressed samples was evaluated. The results are shown in Table 9 Also shown is the measured viscosity of the free radical curable liquid.

[0405] Table 9

[0406]

[0407] from Table 9It is apparent from the Figures that the adhesion obtained with the free radical curable liquids L-1, L-2 and L-8 is insufficient. The free radical curable liquids L-1 and L-2 contain less than 15% by weight of the monofunctional polymerizable compound PCA-2, based on the polymerizable composition, while the free radical curable liquid L-8 contains less than 15% by weight of the multifunctional polymerizable compound.

[0408] For free radical curable liquids L-4 to L-7, the desired viscosity of 5 to 15 mPa.s at 45° C. was obtained in order to spray the free radical curable liquid. Free radical curable liquid L-3, which also gave satisfactory adhesion results, could still be sprayed at a temperature slightly above 45° C.

[0409] Example 2

[0410] This example illustrates the effect of the amount of multifunctional polymerizable compound and monofunctional polymerizable compound A or B in a free radical curable liquid polymerizable composition on adhesion.

[0411] Free Radical Curable Inkjet Inks

[0412] In Example 2, the same cyan free radical UV curable inkjet ink C-1 as in Example 1 was also used.

[0413] Preparation of free radical curable liquids

[0414] By mixing Table 10 Free radical curable liquids L-9 to L-13 were prepared with the components of . The amounts of all compounds are expressed as weight percent based on the total weight of the free radical curable liquid.

[0415] Table 10

[0416]

[0417] Manufacturing of laminated materials

[0418] Laminates were prepared in the same manner as in Example 1, except that free radical curable liquids L-9 to L-12 were now used instead of free radical curable liquids L-1 to L-8.

[0419] Evaluation and Results

[0420] The adhesiveness (peel strength) of the hot pressed samples was evaluated. The results are shown in Table 11 Also shown is the measured viscosity of the free radical curable liquid.

[0421] Table 11

[0422]

[0423]

[0424] Table 11 It is shown that the adhesion obtained with the free radical curable liquid L-9 containing no monofunctional polymerizable compound A or B is insufficient. Compound CE-1 is similar to the monofunctional polymerizable compound B except that a four-membered, rather than a five-membered to seven-membered saturated heterocyclic ring containing a single ether group is present. Good adhesion is obtained with free radical curable liquids L-10 to L-12 containing sufficient amounts of monofunctional polymerizable compound A and multifunctional polymerizable compounds.

[0425] For free radical curable liquids L-10 to L-11, a desired viscosity of 5 to 15 mPa.s at 45°C was obtained in order to spray the free radical curable liquid. Free radical curable liquid L-12, which gave satisfactory adhesion results, can be sprayed at a temperature higher than 45°C, or alternatively, a portion of the higher viscosity SR833S (140 mPa.s at 25°C) can be replaced by the lower viscosity DPGDA (9 mPa.s at 25°C).

[0426] Example 3

[0427] This example illustrates the effect of other polymerizable compounds in a free radical curable liquid on adhesion.

[0428] Free Radical Curable Inkjet Inks

[0429] In Example 3, the same cyan free radical UV curable inkjet ink C-1 as in Example 1 was also used.

[0430] Preparation of free radical curable liquids

[0431] By mixing Table 12 to Table 14 Free radical curable liquids COMP-1 to COMP-5 and INV-1 to INV-14 were prepared with the components of . The amounts of all compounds are expressed as weight percentages based on the total weight of the free radical curable liquid.

[0432] Table 12

[0433]

[0434]

[0435] Table 13

[0436]

[0437]

[0438] Table 14

[0439]

[0440] Manufacturing of laminated materials

[0441] Laminates were prepared in the same manner as in Example 1, except that free radical curable liquids COMP-1 to COMP-5 and INV-1 to INV-14 were now used instead of free radical curable liquids L-1 to L-8.

[0442] Evaluation and Results

[0443] The adhesiveness (peel strength) of the hot pressed samples was evaluated. The results are shown in Table 15 The adhesion of the free radical curable liquid is also shown.

[0444] Table 15

[0445]

[0446]

[0447] Free radical curable liquids COMP-1 to COMP-5 do not achieve good adhesion, even though some are tacky. The latter would be advantageous according to EP 3173229 A (TARKETT), which discloses that incompletely cured UV curable inks improve adhesion. In industrial environments, for reliable manufacturing without vulnerability to dust or scratches, UV-curable compositions that do not exhibit tack are preferred.

[0448] The free radical curable liquids INV-1 and INV-2 show that increasing the amount of surfactant has a negative effect on adhesion. Therefore, an amount of surfactant not exceeding 0.3 wt. % based on the ink is preferred, since with this concentration the desired surface tension for good spreading can be obtained.

[0449] Comparative Example 2 contains CTFA, which differs from the monofunctional polymerizable compound B according to formula (2) in that it contains two ether functions in the six-membered saturated heterocyclic ring. Inventive Example INV-3 shows that CTFA can still be included in the free radical curable liquid when polymerizable compounds A or B (here: PCA-2) are present.

[0450] Comparison of Examples COMP-3 to COMP-5 with INV-4 to INV-14 shows that various other monofunctional and multifunctional polymerizable compounds can be included in the free radical curable liquid with an acceptable effect on adhesion as long as there is sufficient monofunctional polymerizable compound A or B and multifunctional polymerizable compound.

[0451] Example 4

[0452] This example illustrates the effect of the amount of multifunctional polymerizable compound and monofunctional polymerizable compound A or B in a free radical curable liquid polymerizable composition on adhesion.

[0453] Free Radical Curable Inkjet Inks

[0454] In Example 4, the same cyan free radical UV curable inkjet ink C-1 as in Example 1 was also used.

[0455] Preparation of free radical curable liquids

[0456] By mixing Table 16 Free radical curable liquids COMP-6 and INV-15 to INV-17 were prepared with components of . The amounts of all compounds are expressed as weight percent based on the total weight of the free radical curable liquid.

[0457] Table 16

[0458]

[0459]

[0460] Manufacturing of laminated materials

[0461] Laminates were prepared in the same manner as in Example 1, except that free radical curable liquids COMP-6 and INV-15 to INV-17 were now used instead of free radical curable liquids L-1 to L-8.

[0462] Evaluation and Results

[0463] The adhesiveness (peel strength) of the hot pressed samples was evaluated. The results are shown in Table 17 The adhesion of the free radical curable liquid is also shown.

[0464] Table 17

[0465]

[0466] from Table 17 As can be seen from the graph, free radical curable liquid COMP-6 failed to achieve good adhesion compared to free radical curable liquids INV-15 to INV-17. The latter three free radical curable liquids also did not exhibit any tack.

[0467] Example 5

[0468] This example illustrates the effect of the amount of monofunctional polymerizable compounds and multifunctional polymerizable compounds in the polymerizable composition of a free radical curable inkjet ink on adhesion.

[0469] Preparation of free radical curable inkjet inks

[0470] Cyan pigment dispersions were prepared using different types of dispersants in a manner similar to that explained for Example 1. These cyan pigment dispersions were then used to form free radical curable inkjet inks that exhibited good UV curing and reliable jetting characteristics. Table 18 Cyan free radical UV curable inkjet inks COMP-7, COMP-8 and INV-18 to INV-24 were prepared with components of . The weight percentages are based on the total weight of the inkjet ink.

[0471] Table 18

[0472]

[0473]

[0474] Preparation of free radical curable liquids

[0475] By mixing Table 19 The free radical curable liquid FRCL is prepared by using the components of . The amounts of all compounds are expressed as weight percentages based on the total weight of the free radical curable liquid.

[0476] Table 19

[0477] Weight % of compound: FRCL PCA-2 37.9 IBOA 10.0 TPO 8.0 SR833S 39.0 CN3755 4.0 INHIB 1.0 SILMER 0.1

[0478] Manufacturing of laminated materials

[0479] A laminate was prepared in the same manner as in Example 1, except that cyan free radical UV curable inkjet inks COMP-7, COMP-8 and INV-18 to INV-24 and free radical curable liquid FRCL were now used instead of free radical curable inkjet ink C-1 and free radical curable liquids L-1 to L-8, respectively.

[0480] Evaluation and Results

[0481] The adhesiveness (peel strength) of the hot pressed samples was evaluated. The results are shown in Table 20 middle.

[0482] Table 20

[0483]

[0484] from Table 20It should be clear from the Figures that good adhesion could not be obtained with inkjet inks COMP-7 and COMP-8, which had polymerizable compositions without 10 to 90 wt % of one or more monofunctional polymerizable compounds. The best adhesion results were obtained when the polymerizable composition of the free radical curable inkjet ink contained 40 to 80 wt % of one or more monofunctional polymerizable compounds.

[0485] By comparing the adhesion results of the free radical curable inkjet ink INV-24 with the adhesion results of the free radical curable inkjet inks INV-22 and INV-23, degradation can be observed when a multifunctional polymerizable compound having more than two polymerizable groups is included in the inkjet ink.

[0486] Example 6

[0487] This example illustrates a practical implementation using an inkjet printer.Examples 1 to 5 were carried out using a bar coater as this is faster and cheaper.

[0488] Free Radical Curable Inkjet Inks

[0489] A commercial CMYK inkjet ink set from AGFA was used 1550. All inkjet inks are pigmented free radical curable inkjet inks comprising a color pigment and a polymerizable composition containing a monofunctional polymerizable compound particularly preferably in the range of 40 wt % to 80 wt %, based on the total weight of the polymerizable composition.

[0490] Preparation of free radical curable liquids

[0491] By mixing Table 21 The free radical curable liquid FRCL-2 was prepared with the components of . The amounts of all compounds are expressed as weight percentages based on the total weight of the free radical curable liquid.

[0492] Table 21

[0493]

[0494] At 45°C and 1,000 s -1 The viscosity measured at a shear rate of 10 mPa.s.

[0495] Manufacturing of laminated materials

[0496] Composite an image that includes a photo of a landscape, a photo of two children, and rectangles of cyan, magenta, yellow, black, red, blue, and green.

[0497] Use the H 2050i LED and inkjet ink set The image was printed on an opaque white polyvinyl chloride foil P2 of 80 μm thickness using a 1550. The printing parameters were set to: C-speed = 5 / F-speed = 1 / direction = single / UV = double / UV mode = normal / UV power L = 40% / UV power R = 40% / printing mode = Quamity-no masking_single pass flat and quality = 720×720 dpi. The size of the photos and rectangles in the printed image was large to perform a peel strength test on each of them.

[0498] The free radical curable liquid FRCL-2 was applied in different ways. In sample IJ-1, a bar coating of the free radical curable liquid FRCL-2 with a thickness of 10 μm was performed on top of the inkjet printed image. This allowed a direct comparison with the results of Examples 1 to 5.

[0499] In samples IJ-2 and IJ-3, printing of free radical curable inkjet ink and free radical curable liquid FRCL-2 was performed simultaneously. Although in sample IJ-2, the printed image was completely (100%) covered by the free radical curable liquid FRCL-2, the printed image in sample IJ-3 was partially not covered by the free radical curable liquid FRCL-2, so that when laminated, the ink would contact the second thermoplastic sheet C2 by 25% of the surface area.

[0500] In samples IJ-4 and IJ-5, printing was performed in two steps. The free radical curable inkjet ink was first jetted and cured, and then the printed image was introduced into the inkjet printer again, and the free radical curable liquid FRCL-2 was jetted on the printed image and cured. Samples IJ-4 and IJ-5 were printed with the free radical curable liquid FRCL-2 in the same manner as samples IJ-2 and IJ-3 to completely and partially (75%) cover the inkjet printed image, respectively.

[0501] Each of the samples IJ-1 to IJ-5 was then combined with a transparent thermoplastic foil C3 by having the image on the foil P2 facing the transparent thermoplastic foil C3. The assembly of foils P2 and C3 was then hot pressed at a temperature of 160°C and a pressure of 14 bar for 40 seconds.

[0502] Evaluation and Results

[0503] The adhesiveness (peel strength) of hot pressed samples IJ-1 to IJ-5 was evaluated. The results of the peel tests performed on the photographs and the colored rectangles were averaged and shown in Table 22 middle.

[0504] Table 22

[0505]

[0506] from Table 22 As can be seen, the results of the doctor bar coating can be compared with those obtained by actual inkjet printing experiments.

[0507] It can also be seen that the adhesion results of the 2-step printing method are slightly better than the adhesion structure printed in parallel.

[0508] Finally, it can be seen that if the pigmented free radical curable inkjet ink is not fully covered by the free radical curable liquid, the adhesion is degraded.

[0509] Reference numerals list

[0510] Table 23

[0511] 1 Decorative panels 2 Grassroots 3 Tongue 4 Grooves 5 Transparent or opaque thermoplastic foil 6 Transparent thermoplastic foil 7 Decorative layer 10 Upper hot plate 11 Transparent thermoplastic foil 12 Adhesion layer 13 Colored Pattern 14 Transparent or opaque thermoplastic foil 15 Grassroots 16 Lower hot plate

Claims

1. A method for producing a decorative surface, comprising the following steps: - inkjet printing an image on the first thermoplastic foil by jetting one or more pigmented free radical curable inkjet inks onto the first thermoplastic foil and curing them; - applying a free radical curable liquid on the inkjet printed image and curing it as an adhesion layer; as well as - hot pressing the first thermoplastic foil and the second thermoplastic foil into a decorative laminate; wherein at least one of the first and second thermoplastic foils is a transparent thermoplastic foil; wherein the one or more pigmented free radical curable inkjet inks comprise a colored pigment and a polymerizable composition containing from 10% to 90% by weight of one or more monofunctional polymerizable compounds; wherein the radical curable liquid comprises a polymerizable composition containing 15 wt % or more of a multifunctional polymerizable compound and 15 wt % or more of a monofunctional polymerizable compound A or B; wherein all weight percentages wt % are based on the total weight of the polymerizable composition in the pigmented free radical curable inkjet ink or the polymerizable composition in the free radical curable liquid; Wherein the monofunctional polymerizable compound A is a compound according to formula (1): wherein R represents hydrogen or a methyl group; X represents oxygen or an NR'-group; L represents a divalent linking group having not more than 10 carbon atoms; R' is selected from hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted aralkyl, substituted or unsubstituted alkaryl and substituted or unsubstituted aryl or heteroaryl; n represents 0 or 1; and A represents a moiety according to formula (1A): wherein Q represents the atoms necessary to form a five- to eight-membered ring, and the dashed lines represent covalent bonds to carbon atoms; Wherein the monofunctional polymerizable compound B is a compound according to formula (2): wherein R2 represents hydrogen or methyl; L represents a divalent linking group having not more than 10 carbon atoms; n represents 0 or 1; and D represents a five- to seven-membered saturated heterocyclic ring containing a single ether group.

2. The method of claim 1, wherein the first and second thermoplastic foils comprise polyvinyl chloride.

3. The method according to claim 1, wherein the polymerizable compound A or B is selected from: The method according to claim 1 , wherein the radical curable liquid does not contain a polymerizable compound B.

5. The method of claim 1, wherein the free radical curable liquid contains a surfactant in an amount not exceeding 0.3 wt % based on the total weight of the free radical curable liquid.

6. The method of claim 1, wherein the free radical curable liquid is heated to 45°C for 1,000 s -1 The viscosity of the composite is between 5 mPa.s and 15 mPa.s at a shear rate of 1.5 %.

7. The method of claim 1, wherein the free radical curable liquid contains a multifunctional polymerizable compound selected from the group consisting of dipropylene glycol diacrylate, tricyclodecane dimethanol diacrylate, and 1,6-hexanediol diacrylate.

8. The method according to claim 1, wherein the free radical curable liquid contains a polymerizable composition containing 20 wt % or more of a multifunctional polymerizable compound and 30 wt % or more of a monofunctional polymerizable compound A or B, based on the total weight of the polymerizable composition.

9. The method of claim 1, wherein the one or more pigmented free radical curable inkjet inks contain 40 wt% to 80 wt% of one or more monofunctional polymerizable compounds, based on the total weight of the polymerizable composition.

10. The method of claim 1, wherein the one or more pigmented free radical curable inkjet inks and / or the free radical curable liquid are cured by electron beam or by UV LED.

11. The method according to claim 1, wherein the adhesive layer is applied by a coating technique or a printing technique additionally selected from flexographic printing and gravure printing.

12. The method of claim 1, wherein the adhesive layer is applied by spraying.

13. The method of claim 1, wherein the one or more pigmented free radical curable inkjet inks form an ink set comprising a) Cyan free radical curable inkjet ink containing copper phthalocyanine pigment or CI Pigment Blue 60; b) a red free radical curable inkjet ink containing a pigment selected from the group consisting of CI Pigment Red 122, CI Pigment Red 144, CI Pigment Red 176, CI Pigment Red 188, CI Pigment Red 207, CI Pigment Red 242, CI Pigment Red 254, CI Pigment Red 272 and mixed crystals thereof; c) a yellow free radical curable inkjet ink containing a pigment selected from the group consisting of CI Pigment Yellow 83, CI Pigment Yellow 97, CI Pigment Yellow 93, CI Pigment Yellow 110, CI Pigment Yellow 120, CI Pigment Yellow 150, CI Pigment Yellow 151, CI Pigment Yellow 154, CI Pigment Yellow 155, CI Pigment Yellow 175, CI Pigment Yellow 180, CI Pigment Yellow 181, CI Pigment Yellow 194, CI Pigment Yellow 213, CI Pigment Yellow 214 and mixed crystals thereof; and d) Black free radical curable inkjet ink containing carbon black pigment.

14. A decorative laminate comprising an inkjet printed decorative image printed with one or more pigmented free radical curable inkjet inks and an adhesive layer of a free radical curable liquid between a first thermoplastic foil and a second thermoplastic foil, wherein at least one of the first and second thermoplastic foils is a transparent thermoplastic foil; wherein the one or more pigmented free radical curable inkjet inks comprise a colored pigment and a polymerizable composition containing from 10% to 90% by weight of one or more monofunctional polymerizable compounds; wherein the radical curable liquid comprises a polymerizable composition containing 15 wt % or more of a multifunctional polymerizable compound and 15 wt % or more of a monofunctional polymerizable compound A or B; wherein all weight percentages wt % are based on the total weight of the polymerizable composition in the pigmented free radical curable inkjet ink or the free radical curable liquid; Wherein the monofunctional polymerizable compound A is a compound according to formula (1): wherein R represents hydrogen or a methyl group; X represents oxygen or an NR'-group; L represents a divalent linking group having not more than 10 carbon atoms; R' is selected from hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted aralkyl, substituted or unsubstituted alkaryl and substituted or unsubstituted aryl or heteroaryl; n represents 0 or 1; and A represents a moiety according to formula (1A): wherein Q represents the atoms necessary to form a five- to eight-membered ring, and the dashed lines represent covalent bonds to carbon atoms; Wherein the monofunctional polymerizable compound B is a compound according to formula (2): wherein R2 represents hydrogen or methyl; L represents a divalent linking group having not more than 10 carbon atoms; n represents 0 or 1; and D represents a five- to seven-membered saturated heterocyclic ring containing a single ether group.

15. The decorative laminate of claim 14, wherein the first and second thermoplastic foils comprise polyvinyl chloride.

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