Ink kits and inkjet printing methods

Abstract

An ink kit for manufacturing decorative laminates comprises a colored free radical curable inkjet ink and a free radical curable liquid, wherein the colored free radical curable inkjet ink comprises a colored pigment and a polymerizable composition, the polymerizable composition containing 10% to 90% by weight of one or more monofunctional polymerizable compounds; wherein the free radical curable liquid comprises a polymerizable composition, the polymerizable composition containing 15% by weight or more of a polyfunctional polymerizable compound and 15% by weight or more of a specific monofunctional polymerizable compound; and wherein all weight percentages are based on the total weight of the polymerizable composition in the colored free radical curable inkjet ink or the polymerizable composition in the free radical curable liquid.

Description

Technical Field

[0001] This invention relates to ink kits and inkjet printing methods thereon, particularly for the manufacture of decorative laminates, such as decorative laminates of PVC (polyvinyl chloride), also known as vinyl tiles or vinyl tapes, for which the abbreviation LVT (luxury vinyl tile) is commonly used. Background Technology

[0002] Industrial inkjet printing systems are increasingly replacing gravure, offset, and flexographic printing for various applications because they are capable of short production runs at low cost and producing personalized products.

[0003] Decorative panels for furniture and flooring have traditionally been manufactured using gravure printing to provide decorative images of the panels, typically of the wood. Industrial inkjet printing systems have been introduced for the manufacture of wood-based decorative panels.

[0004] The main drawback of these wood-based and paper-based decorative panels is their limited water resistance, which hinders their use in bathrooms and kitchens. This problem has been solved with gravure-printed LVT, in which decorative images are laminated between two PVC sheets.

[0005] To date, industrial inkjet printing systems have not been used in LVT due to adhesion issues between decorative images and PVC sheets.

[0006] Several water-based inkjet technologies suitable for improving the adhesion of LVT (wood-based decorative panels) have been explored, such as those described 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 floor or wall coverings using a water-based ink composition comprising one or more acrylic copolymers and silica, and the covering material comprising polyvinyl chloride. However, while some water-based inkjet technologies offer improved adhesion, the water resistance of such panels is generally reduced because the hydrophilic layer tends to swell upon exposure to water. In addition, EP 3738782 A (SIHL) discloses the use of a microporous ink-receiving layer comprising inorganic particles and a binder, and further comprising more than 6% by weight of a polymerizable and / or crosslinkable monomer or polymer compound having at least one (meth)acrylate moiety or a polymer crosslinked via the (meth)acrylate moiety, based on the weight of the ink-receiving layer.

[0007] The use of UV-curable inkjet systems has also been proposed, for example in EP 3095614 A (AGFA). However, additional measures are needed to improve the adhesion of LVT printed with UV-curable inkjet inks to a commercially acceptable level.

[0008] EP 3173229 A (TARKETT) discloses a method for producing LVT, wherein the decorative layer is printed with UV-curable ink, and wherein UV curing is performed using a UV LED source with spectral emission in the 345-420 nm range, wherein curing proceeds to the point where the UV-curable ink is not fully cured during lamination. However, this method makes it susceptible to scratches and dust in industrial environments.

[0009] In EP 3300916 A (AGFA), an additional adhesive layer containing a vinyl chloride-vinyl acetate-vinyl alcohol copolymer is applied over the cured UV inkjet ink to improve adhesion. However, this adhesive layer is coated with an organic solvent, which is not preferred due to safety risks in industrial environments.

[0010] Therefore, there is still a need for improved inkjet technology for manufacturing decorative laminates that exhibit good water resistance and adhesion without the need for organic solvents. Summary of the Invention

[0011] To overcome the above problems, a preferred embodiment of the present invention has been implemented using the ink kit as defined in claim 1.

[0012] Surprisingly, it was discovered that using a free-radical curable liquid containing no colored pigments or polymeric dispersants and having a specific polymerizable composition allows for good adhesion properties 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 this can be explained by the weak boundary layer theory. The colored pigments and polymeric dispersants in the ink layer concentrate near the bonding surface and form a weak bond with the PVC sheet to be laminated thereon.

[0013] Other advantages and embodiments of the present invention will become apparent from the following description. Attached Figure Description

[0014] Figure 1A cross-section of a decorative panel (1) is shown, the decorative panel comprising a base layer (2) having a tongue (3) and a groove (4), the base layer having a transparent or opaque thermoplastic foil (5) and a transparent thermoplastic foil (6) laminated on its top side, 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) includes a colored pattern and an adhesive layer.

[0015] Figure 2 Four ways in which the invention can be utilized are shown.

[0016] 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) with a colored pattern (13) and an adhesive layer (12) and a base layer (15).

[0017] Figure 2 Figure B illustrates 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) with a colored pattern (13) and an adhesive layer (12), a transparent or opaque thermoplastic foil (14), and a base layer (15).

[0018] Figure 2 Figure C 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) and a base layer (15) carrying a colored pattern (13) and an adhesive layer (12).

[0019] Figure 2 .D illustrates 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) carrying a colored pattern (13) and an adhesive layer (12) and a base layer (15). Detailed Implementation

[0020] definition

[0021] The term "monofunctional polymerizable compound" means that a polymerizable compound contains a single polymerizable group.

[0022] The term "bifunctional polymerizable compound" means that a polymerizable compound contains two polymerizable groups.

[0023] The term "multifunctional polymerizable compound" in this invention means that a polymerizable compound contains two or more polymerizable groups.

[0024] The term "alkyl" refers to all possible variations for each number of carbon atoms in an alkyl group, namely 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.

[0025] Unless otherwise specified, substituted or unsubstituted alkyl groups are preferably C1-C6-alkyl groups.

[0026] Unless otherwise specified, the substituted or unsubstituted alkenyl group is preferably C2-C6-alkenyl.

[0027] Unless otherwise specified, the substituted or unsubstituted alkynyl group is preferably C2-C6-alkynyl.

[0028] Unless otherwise specified, the substituted or unsubstituted aralkyl group is preferably a phenyl or naphthyl group containing one, two, three or more C1-C6-alkyl groups.

[0029] Unless otherwise specified, substituted or unsubstituted alkylaryl groups are preferably C7-C groups containing phenyl or naphthyl groups. 20 -alkyl.

[0030] Unless otherwise specified, the substituted or unsubstituted aryl group is preferably phenyl or naphthyl.

[0031] 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 combinations thereof.

[0032] In the context of substituted alkyl groups, the term "substituted" means that the alkyl group can be replaced by atoms other than those normally present in the group (i.e., carbon and hydrogen). For example, substituted alkyl groups may contain halogen atoms or thiol groups. Unsubstituted alkyl groups contain only carbon and hydrogen atoms.

[0033] Unless otherwise specified, the substituted alkyl, substituted alkenyl, substituted alkynyl, substituted aralkyl, substituted alkylaryl, 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, ketone, aldehyde, sulfoxide, sulfone, sulfonate, sulfonamide, -Cl, -Br, -I, -OH, -SH, -CN and -NO2.

[0034] Ink kit

[0035] An ink kit for manufacturing decorative laminates according to a preferred embodiment of the present invention comprises coloring free radical curable inkjet ink and free radical curable liquid.

[0036] The coloring free radical curable inkjet ink comprises a colored pigment and a polymerizable composition, wherein the polymerizable composition contains 10% to 90% by weight of one or more monofunctional polymerizable compounds.

[0037] The free radical curable liquid comprises a polymerizable composition containing 15% by weight or more of a multifunctional polymerizable compound and 15% by weight or more of a monofunctional polymerizable compound A or B.

[0038] All weight percentages (%) are based on the total weight of the polymerizable composition in the colored radical-curable inkjet ink or the polymerizable composition in the radical-curable liquid.

[0039] Among them, the monofunctional polymerizable compound A is a compound according to formula (1):

[0040]

[0041] Where R represents hydrogen or methyl; X represents oxygen or NR'- group; L represents a divalent linker having no 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 alkylaryl, and substituted or unsubstituted aryl or heteroaryl; n represents 0 or 1; and A represents a portion according to formula (1A):

[0042]

[0043] Where Q represents the atoms necessary to form five- to eight-membered rings, and the dashed lines represent covalent bonds to carbon atoms;

[0044] Among them, the monofunctional polymerizable compound B is a compound according to formula (2):

[0045]

[0046] Where R2 represents hydrogen or methyl; L represents a divalent linker with no more than 10 carbon atoms; n represents 0 or 1; and D represents a five- to seven-membered saturated heterocycle containing a single ether group.

[0047] The coloring free radical curable inkjet inks in the ink kit are preferably inkjet inks of different colors. The ink kit can be a standard CMYK ink kit, but is preferably a CRYK ink kit, wherein magenta (M) ink is replaced by 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. Good adhesion to red ink is achieved when the pigments are selected from the following pigments: 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 their mixed crystals.

[0048] The preferred ink kits include: a) a cyan radical-curable inkjet ink containing CI Pigment Blue 60 or copper phthalocyanine pigment; b) a red radical-curable inkjet ink containing pigments selected from: 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 radical-curable inkjet ink containing pigments selected from... The following pigments are included: 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 their mixed crystals; and d) black radical-curable inkjet inks containing carbon black pigments. This ink kit allows for excellent reproduction of wood-based colored patterns with little or no metamerism and good adhesion.

[0049] Compared to single-pass inkjet units, multi-pass inkjet units allow for a smaller number of printheads, enabling the use of ink sets with different colors. For example, an ink set could be CMRYK inkjet ink. This type of ink set allows for the accurate reproduction of both wood grain patterns with more vibrant colors and other "fashionable" patterns.

[0050] The ink kit can be expanded with other colored free radical curable inkjet inks (such as brown, green, blue, purple and / or orange) to further broaden the color gamut of the ink kit.

[0051] The ink kit can also be expanded by combining full-density inkjet inks with low-density inkjet inks. Combinations of dark and light inks and / or black and gray inks improve image quality by reducing graininess. A preferred ink kit contains both dark and light black inkjet inks because this allows for a minimal increase in the number of printheads while still sufficiently reducing graininess based on the principle of undercolor removal.

[0052] Free radical curable liquid

[0053] The free radical curable liquid differs from free radical curable inkjet ink in that it does not impart color when applied to a white substrate. The absence of colored pigments and dispersants in the free radical curable liquid improves the adhesion of decorative laminates.

[0054] The free radical curable liquid used in this invention comprises a polymerizable composition containing 15% by weight or more of a multifunctional polymerizable compound and 15% by weight or more of a monofunctional polymerizable compound A or B.

[0055] All weight percentages (%) are based on the total weight of the polymerizable composition in the free radical curable liquid;

[0056] Among them, the monofunctional polymerizable compound A is a compound according to formula (1):

[0057]

[0058] Where R represents hydrogen or methyl; X represents oxygen or NR'- group; L represents a divalent linker having no 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 alkylaryl, and substituted or unsubstituted aryl or heteroaryl; n represents 0 or 1; and A represents a portion according to formula (1A):

[0059]

[0060] Where Q represents the atoms necessary to form five- to eight-membered rings, and the dashed lines represent covalent bonds to carbon atoms;

[0061] Among them, the monofunctional polymerizable compound B is a compound according to formula (2):

[0062]

[0063] Where R2 represents hydrogen or methyl; L represents a divalent linker with no more than 10 carbon atoms; n represents 0 or 1; and D represents a five- to seven-membered saturated heterocycle containing a single ether group.

[0064] In a preferred embodiment of the ink kit, the free radical curable liquid contains a polymerizable composition, which, based on the total weight of the polymerizable composition, contains 20% by weight or more of a multifunctional polymerizable compound and 30% by weight or more of a monofunctional polymerizable compound A or B.

[0065] In a preferred embodiment, the free radical curable liquid is at 45°C for 1,000 seconds. -1 It has a viscosity between 5 mPa·s and 15 mPa·s at a shear rate. This viscosity allows the free radical curable liquid to be sprayed through an industrial printhead. If the free radical curable liquid is applied not through a printhead, but through coating or printing techniques (such as flexographic or gravure printing), a higher viscosity can be used to improve layer quality.

[0066] It has been observed that excessive surfactants can degrade the adhesion of decorative laminates. In a preferred embodiment, the free radical curable liquid contains a surfactant in an amount not exceeding 0.3% by weight, preferably 0% to 0.2% by weight, 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] Where R represents hydrogen or methyl; X represents oxygen or NR'- group; L represents a divalent linker having no 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 alkylaryl, and substituted or unsubstituted aryl or heteroaryl; n represents 0 or 1; and A represents a portion according to formula (1A):

[0071]

[0072] Where Q represents the atoms necessary to form five- to eight-membered rings, and the dashed lines represent covalent bonds to carbon atoms.

[0073] In the preferred embodiment, R represents hydrogen. When R represents hydrogen, a higher curing rate is observed.

[0074] In the preferred embodiment, X represents oxygen. A higher curing rate is also observed when X represents oxygen.

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

[0076] In a preferred embodiment, the divalent linker L is preferably an unsubstituted straight carbon chain having no more than 10 carbon atoms, more preferably having 1 to 6 carbon atoms, and 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] Where Q represents the atoms necessary to form five- to eight-membered rings.

[0081] Preferred polymerizable compound A in Table 1 The information is provided in the text.

[0082] Table 1

[0083]

[0084]

[0085]

[0086] (Meth)acrylated compounds are preferred over (meth)acrylamide compounds. (Meth)acrylamide compounds can be prepared according to the following scheme disclosed in CN 108239236 (CHENGDU POLLOCK TECH CO), where R represents H; or prepared by the following scheme: where step 1 is... Step 2 is disclosed in Amino Acids, 40, 197-204 (2011) and Hyde et al., Organic Process Research and Development, 23, 1860-1871 (2019) and in WO 2018 / 132370 (ISP INVESTMENTS).

[0087] Particularly preferred monofunctional polymerizable compounds A are PCA-1, PCA-2, PCA-4, PCA-6, and PCA-11. Most preferred compounds are PCA-1, PCA-2, and PCA-6.

[0088] Monofunctional polymerizable compound A can also be used in combination with one or more other monofunctional polymerizable compounds A and / or with one or more monofunctional polymerizable compounds B.

[0089] Based on the total weight of the polymerizable composition of the free radical curable liquid, the amount of monofunctional polymerizable compounds A and / or B is at least 15% by weight, preferably at least 20% by weight, and most preferably at least 24% by weight.

[0090] Monofunctional polymerizable compound B

[0091] Monofunctional polymerizable compound B is a compound according to formula (2):

[0092]

[0093] Where R2 represents hydrogen or methyl; L represents a divalent linker with no more than 10 carbon atoms; n represents 0 or 1; and D represents a five- to seven-membered saturated heterocycle containing a single ether group.

[0094] In a preferred embodiment, R2 represents hydrogen. When R2 represents hydrogen, a higher curing speed is observed.

[0095] In the preferred embodiment, n represents 1.

[0096] In a preferred embodiment, the divalent linker L is preferably a straight carbon chain having no more than 10 carbon atoms, more preferably having 1 to 6 carbon atoms, and more preferably a group selected from -CH2-, -CH2-CH2-, -CH2-CH2-CH2-, -CH2-CH2-CH2-CH2- and -CH2-CH2-O-CH2-.

[0097] In an even more preferred embodiment, D represents a five-membered saturated heterocycle containing a single ether group.

[0098] The particularly preferred polymerizable compound B is in Table 2 The information is provided in the text.

[0099] Table 2

[0100]

[0101] Monofunctional polymerizable compound B can also be used in combination with one or more other monofunctional polymerizable compounds B and / or with one or more monofunctional polymerizable compounds A.

[0102] In a preferred embodiment, the radical-curable liquid contains only one or more polymerizable compounds A, and does not contain polymerizable compound B. It has been observed that the printing reliability of radical-curable liquids containing polymerizable compound B is inferior to that of corresponding radical-curable liquids containing polymerizable compound A, especially when evaluating latency. Latency is the ability of a radical-curable liquid to print immediately after a period of inactivity in the printhead without nozzle failure. Poor latency is typically caused by the evaporation of the polymerizable compound from the nozzles in the printhead.

[0103] Multifunctional polymerizable compounds

[0104] There are no practical limitations on the polyfunctional polymerizable compounds. Any polyfunctional monomer and oligomer capable of free radical polymerization can be used as a polyfunctional polymerizable compound. Suitable polyfunctional polymerizable compounds can be any polyfunctional monomer and / or oligomer found in Polymer Handbook, Volumes 1+2, 4th Edition, edited by J. BRANDRUP et al., Wiley-Interscience, 1999.

[0105] The multifunctional polymerizable compound can 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, dimethyloltricyclodecane diacrylate, bisphenol A EO (ethylene oxide) adduct diacrylate, bisphenol A PO (propylene oxide) adduct diacrylate, hydroxy-neopentyl ester neopentyl glycol diacrylate, propoxylated neopentyl glycol diacrylate, alkoxylated dimethyloltricyclodecane diacrylate and polytetramethylene glycol diacrylate, trimethylolpropane triacrylate, EO-modified trimethylolpropane triacrylate, tri(propylene glycol) triacrylate, caprolactone-modified trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, pentaerythritol ethoxytetraacrylate, dipentaerythritol hexaacrylate, bis(trimethylolpropane)tetraacrylate, glycerol propoxytetraacrylate, alkyl Oxylated cyclohexanone dimethyl diacrylate, caprolactam-modified pentaerythritol hexaacrylate, alkoxylated cyclohexanone dimethyl diacrylate, alkoxylated hexanediol diacrylate, dioxanediol diacrylate, dioxanediol diacrylate, cyclohexanone dimethyl diacrylate, diethylene glycol diacrylate, neopentyl glycol diacrylate, vinyl ether acrylate, propoxylated glycerol triacrylate and propoxylated trimethylolpropane triacrylate, bis(trimethylolpropane)tetraacrylate, bis(pentaerythritol) pentaacrylate, ethoxylated pentaerythritol tetraacrylate, methoxylated diol acrylate and acrylate.

[0106] Preferred vinyl ether acrylates are those disclosed in US 6310115 (AGFA). Particularly preferred compounds are 2-(2-vinyloxyethoxy)ethyl acrylate. Other suitable vinyl ether acrylates are those disclosed in columns 3 and 4 of US 6767980 B (NIPPON SHOKUBAI).

[0107] In a particularly preferred embodiment, the free radical curable liquid contains a multifunctional polymerizable compound selected from dipropylene glycol diacrylate, tricyclodecanedimethylethanol diacrylate, and 1,6-hexanediol diacrylate.

[0108] In the most preferred embodiment, the radical-curable liquid contains at least tricyclodecanediethanol diacrylate as a multifunctional polymerizable compound. Adhesion is maximized when this polymerizable compound is present.

[0109] Based on the total weight of the polymerizable composition in the free radical curable liquid, the presence of the multifunctional polymerizable compound is at least 15% by weight, preferably 20% to 80% by weight, more preferably 30% to 70% by weight, and most preferably 40% to 60% by weight. Within the preferred range, adhesion is maximized.

[0110] In a particularly preferred embodiment, the free radical curable liquid contains tricyclodecanediethanol diacrylate in an amount of at least 15% by weight, preferably 20% to 80% by weight, more preferably 30% to 70% by weight, and most preferably 40% to 60% by weight, based on the total weight of the polymerizable composition in the free radical curable liquid. Within the preferred range, adhesion is maximized.

[0111] Other monofunctional polymerizable compounds

[0112] There are no practical limitations on other monofunctional polymerizable compounds. Any monofunctional monomer and oligomer capable of free radical polymerization can be used as other monofunctional polymerizable compounds. Suitable other monofunctional polymerizable compounds can be any monofunctional monomer and / or oligomer found in Polymer Handbook, Volumes 1+2, 4th Edition, Wiley-Interscience, 1999, edited by J. BRANDRUP et al.

[0113] In a preferred embodiment, other monofunctional polymerizable compounds include olefinically unsaturated polymerizable groups selected from acrylates, methacrylates, acrylamide, methacrylamide, styrene, maleate, fumarate, itaconic acid, vinyl ethers, vinyl esters, allyl ethers, and allyl esters.

[0114] 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, isoamylstyl acrylate, isostearyl acrylate, 2-ethylhexyl-diethylene glycol 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-acryloyloxyethyl succinic acid, 2-acryloyloxyethyl phthalic acid, 2-acryloyloxyethyl-2-hydroxyethyl-phthalic acid, lactone-modified flexible acrylate, and tert-butylcyclohexyl acrylate.

[0115] Acrylamide or substituted acrylamides (such as acryloylmorpholine) can also be used as other monofunctional polymerizable compounds.

[0116] Other particularly preferred polymerizable compounds include those according to formula (2B):

[0117]

[0118] Wherein R2 represents hydrogen or methyl; L represents a divalent linker having no more than 10 carbon atoms; n represents 0 or 1; and D represents a three- to four-membered saturated heterocycle containing a single ether group. These cyclic ethers themselves cannot serve as effective monofunctional polymerizable compounds B, but when combined with one or more monofunctional polymerizable compounds A and / or B, adhesion can be further improved. In a preferred embodiment, R2 represents hydrogen. When R2 represents hydrogen, a higher curing rate is observed.

[0119] In the preferred embodiment, n represents 1.

[0120] In a preferred embodiment, the divalent linker L is preferably a straight carbon chain having no more than 10 carbon atoms, more preferably having 1 to 6 carbon atoms, and more preferably a group selected from -CH2-, -CH2-CH2-, -CH2-CH2-CH2-, -CH2-CH2-CH2-CH2- and -CH2-CH2-O-CH2-.

[0121] The particularly preferred polymerizable compound B is in Table 3 The information is provided in the text.

[0122] Table 3

[0123]

[0124] Free radical curable inkjet ink

[0125] The one or more colored free radical curable inkjet inks contain colored pigments as colorants and have a polymerizable composition containing 10% to 90% by weight of one or more monofunctional polymerizable compounds. Therefore, this means that the colored free radical curable inkjet inks contain at least 10% by weight of polyfunctional polymerizable compounds in the polymerizable composition. The presence of at least 10% by weight of polyfunctional polymerizable compounds provides the necessary cohesive strength for the ink layer. To maximize adhesion, the one or more colored free radical curable inkjet inks preferably contain 40% to 80% by weight of one or more monofunctional polymerizable compounds based on the total weight of the polymerizable composition.

[0126] In a preferred embodiment, the one or more free radical-curable inkjet inks are cured at 45°C for 1,000 seconds. -1It exhibits a viscosity between 5 mPa·s and 15 mPa·s at shear rates. This viscosity allows free radical-curable inkjet inks to be ejected through reliable industrial printheads.

[0127] 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 thermoplastic foil.

[0128] Colored pigments

[0129] Colored pigments can be black, cyan, magenta, yellow, red, orange, purple, blue, green, brown, or mixtures thereof. Colored pigments can be selected from those disclosed in HERBST, Willy et al., Industrial Organic Pigments, Production, Properties, Applications. 3rd Edition, Wiley-VCH, 2004. ISBN 3527305769.

[0130] Particularly preferred pigments for cyan water-based inkjet inks are CI Pigment Blue 60 or copper phthalocyanine pigments, more preferably CI Pigment Blue 15:3 or CI Pigment Blue 15:4.

[0131] Red radical curable inkjet inks preferably contain pigments selected from the following: 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.

[0132] Yellow free radical curable inkjet ink preferably contains pigments selected from the following: 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.

[0133] For black inks, suitable pigment materials include carbon black, such as Regal from Cabot Co. TM 400R, Mogul TM L, Elftex TM320, or Carbon Black FW18 or 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, obtained from MITSUBISHI CHEMICAL Co. MA8, as well as CI Pigment Black 7 and CI Pigment Black 11.

[0134] Mixed crystals can also be used. Mixed crystals are also known as solid solutions. For example, under certain conditions, different quinacridones are mixed together to form a solid solution, which is entirely different from a physical mixture of compounds and the compounds themselves. In a solid solution, the molecules of the components enter 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 the 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 patterns 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.

[0135] Mixtures of pigments can also be used. For example, black inkjet ink can contain carbon black pigment and at least one pigment selected from blue, cyan, magenta, and red pigments. This type of black inkjet ink allows for easier and better color management of wood.

[0136] The pigment particles in colored inkjet inks should be small enough to allow the ink to flow freely through the inkjet printing apparatus, especially at the jet nozzles. Small particles are also desirable for achieving maximum color intensity and reducing sedimentation.

[0137] The average particle size of the pigment in the colored 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.

[0138] Based on the total weight of the colored inkjet ink, pigment is used in the inkjet ink in an amount of 0.1% to 20% by weight, preferably 1% to 10% by weight, and most preferably 2% to 6% by weight. A pigment concentration of at least 2% by weight is preferred to reduce the amount of inkjet ink required to produce the colored pattern, while a pigment concentration of more than 5% by weight reduces the color gamut of the colored pattern printed with a printhead having a nozzle diameter of 20 μm to 50 μm.

[0139] When printing colored free radical inkjet inks onto thermoplastic foils or substrates with insufficient whiteness, white colored free radical curable inkjet inks can be included in the ink kit.

[0140] White inkjet inks preferably contain pigments with a high refractive index, preferably greater than 1.60, more preferably greater than 2.00, more preferably greater than 2.50, and most preferably greater than 2.60. Such white pigments typically have very high hiding power, meaning that a limited amount of white ink is needed to cover the color and defects of the core layer. The most preferred white pigment is titanium dioxide.

[0141] Based on the total weight of the white inkjet ink, the white inkjet ink preferably contains a white pigment in an amount of 8% to 30% by weight, more preferably 12% to 25% by weight.

[0142] The number-average particle size of the white pigment is preferably between 150 nm and 500 nm, and most preferably between 180 nm and 300 nm. When the average diameter is less than 150 nm, sufficient hiding power cannot be obtained, and when the average diameter exceeds 500 nm, the ink's storage capacity and ejection adaptability tend to decrease.

[0143] Number-average particle size was best determined by photon correlation spectroscopy at a wavelength of 633 nm using a 4 mW HeNe laser on diluted samples of colored inkjet ink. A suitable particle size analyzer was a Malvern from Goffin-Meyvis. TM nano-S. For example, a sample can be prepared by adding a drop of ink to a cuvette containing 1.5 mL of ethyl acetate and mixing until a homogeneous sample is obtained. The particle size is measured as the average of three consecutive measurements, which consist of six 20-second runs.

[0144] dispersant

[0145] Coloring free radical curable inkjet inks contain dispersants to further improve pigment dispersion characteristics. The dispersants are preferably polymeric dispersants. These dispersants improve the reliability of inkjet printing methods due to their typically low settling velocities, especially when they contain secondary or tertiary amine groups.

[0146] Typical polymer dispersants are copolymers of two monomers, but they can contain three, four, five, or even more monomers. The properties of a polymer dispersant depend on both the nature of the monomers and their distribution within the polymer. Copolymer dispersants preferably have the following polymer composition:

[0147] • Statistically aggregated monomers (e.g., monomers A and B aggregate to form ABBAABAB);

[0148] • Alternating polymerization of monomers (e.g., monomers A and B polymerize to form ABABABAB);

[0149] • Monomers that undergo gradient polymerization (e.g., monomers A and B polymerize into AAABAABBABBBB);

[0150] • Block copolymers (e.g., monomers A and B polymerized into AAAAABBBBBB), where the block length of each block (2, 3, 4, 5 or more) is important for the dispersing ability of the polymer dispersant;

[0151] • Graft copolymers (graft copolymers consist of a polymer backbone and polymer side chains attached to the backbone); and

[0152] • Mixed forms of these polymers, such as block gradient copolymers.

[0153] The polymer dispersant preferably has a number average molecular weight Mn between 500 and 30,000, more preferably between 1,500 and 10,000.

[0154] The polymer 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.

[0155] The polymer dispersant preferably has a polydispersity index (PD) of less than 2, more preferably less than 1.75, and most preferably less than 1.5.

[0156] Commercial examples of polymer dispersants are as follows:

[0157] ·DISPERBYK TM Dispersant, purchased from BYK CHEMIE GMBH;

[0158] SOLSPERSE TM Dispersant, purchased from LUBRIZOL;

[0159] ·TEGO TM DISPERS TM Dispersant, obtained from EVONIK;

[0160] ·EDAPLAN TMDispersant, derived from CHEMIE;

[0161] ·ETHACRYL TM Dispersant, obtained from LYONDELL;

[0162] ·GANEX TM Dispersant, obtained from ISP;

[0163] DISPEX TM and EFKA TM Dispersant, obtained from BASF;

[0164] ·DISPONER TM Dispersant, derived from DEUCHEM.

[0165] Particularly preferred polymer dispersants include Solsperse from LUBRIZOL. TM Dispersant, Efka from BASF TM Dispersant, Disperbyk, obtained from BYK CHEMIE GMBH TM Dispersant and Ajisper from AJINOMOTO FINE-TECHNOCo TM Dispersant. A particularly preferred dispersant is Solsperse from LUBRIZOL. TM Dispersants 32000, 35000 and 39000, and Disperbyk from BYK CHEMIE GMBH. TM 162.

[0166] The dispersant can be used alone or in combination of two or more of them.

[0167] Based on the weight of the pigment, the polymer dispersant is preferably used in an amount of 2% to 600% by weight, more preferably 5% to 200% by weight, and most preferably 50% to 90% by weight.

[0168] Dispersing synergists

[0169] Dispersing synergies typically consist of anionic and cationic moieties. The anionic moieties of dispersing synergies exhibit a certain molecular similarity to colored pigments, while the cationic moieties consist of one or more protons and / or cations to compensate for the charge of the anionic moieties.

[0170] The dispersing synergist is preferably added in a smaller amount than the polymeric dispersant. The ratio of polymeric dispersant to dispersing synergist depends on the pigment and should be determined experimentally. Typically, the ratio of polymeric dispersant by weight to dispersing synergist by weight is selected between 2:1 and 100:1, preferably between 2:1 and 20:1.

[0171] Commercially available suitable dispersants include Solsperse from LUBRIZOL. TM 5000 and Solsperse TM 22000.

[0172] For the magenta ink used, particularly preferred pigments are diketopyrrolopyrrole pigments or quinacridone pigments. Suitable dispersing 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).

[0173] In the dispersion of CI Pigment Blue 15:3, sulfonated copper phthalocyanine dispersing synergist, such as Solsperse from LUBRIZOL, is preferably used. TM 5000. Dispersing synergists suitable for yellow inkjet inks include those disclosed in EP 1790697 A (AGFAGRAPHICS).

[0174] polymerizable compounds

[0175] The one or more coloring free radical curable inkjet inks comprise a polymerizable composition containing one or more monofunctional polymerizable compounds in an amount of 10% to 90% by weight, preferably 40% to 80% by weight, based on the total weight of the polymerizable composition.

[0176] Any monomer and oligomer capable of free radical polymerization can be used as the polymerizable compound. The viscosity of the free radical curable inkjet ink can be adjusted by changing the ratio between the monomer and the oligomer. The polymerizable compound can be any monomer and / or oligomer found in Polymer Handbook, Volumes 1+2, 4th Edition, Wiley-Interscience, 1999, edited by J. BRANDRUP et al.

[0177] Polymerizable compounds used in free radical curable liquids can also be suitably used in coloring free radical curable inkjet inks.

[0178] Photoinitiation system

[0179] If electron beam curing is not used to cure radical-curable liquids or coloring radical-curable inkjet inks, a photoinitiation system is used. The photoinitiation system contains at least one radical photoinitiator, but preferably contains a photoinitiator and, more preferably, a combination of one or more co-initiators.

[0180] In free radical curable liquids and inkjet inks, photoinitiators can be Norrish Type I or Norrish Type II initiators. Norrish Type I initiators are those that cleave upon excitation, immediately generating initiating groups. Norrish Type II initiators are those photoinitiators that are activated by photochemical radiation and form free radicals by abstracting hydrogen from a second compound, which then becomes the actual initiating free radical. This second compound is referred to as a polymerization synergist or co-initiator. Both Type I and Type II photoinitiators can be used alone or in combination in this invention.

[0181] The photoinitiation system preferably contains 4% to 20% by weight of a free radical photoinitiator and a co-initiator.

[0182] Norrish Type I photoinitiator

[0183] Preferred Norrish type I photoinitiators for the UV-curable inkjet inks used in this invention are acylphosphine oxide and α-hydroxyketone photoinitiators.

[0184] When UV curing is performed using UV LEDs with long wavelengths greater than 360 nm, acylphosphine oxide photoinitiators are particularly advantageous for curability, and this advantage is even greater when acylphosphine oxide photoinitiators are further combined with Norrish type II photoinitiators containing thioxanthone groups.

[0185] Preferred examples of acylphosphine oxide photoinitiators include, but are not specifically limited to, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, and bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide.

[0186] 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-diphenylphosphine oxide), Omnirad TMTPO-L ((2,4,6-trimethylbenzoyl)phenyl phosphite ethyl ester), all of which are available from IGM RESINS.

[0187] Based on the total weight of the UV-curable inkjet ink, the content of acylphosphine oxide photoinitiator is preferably 3% to 15% by weight, more preferably 5% to 13% by weight, and even more preferably 6% to 10% by weight.

[0188] Examples of α-hydroxy ketone photoinitiators include, but are not limited to, 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenylprop-1-one, and 1-[4-(2-hydroxyethoxy)-phenyl]2-hydroxy-2-methyl-1-prop-1-one.

[0189] Examples of commercial α-hydroxyketone photoinitiators include, but are not limited to, Omnirad derived from IGM RESINS. M 1173, Omnirad TM 184 and Omnirad TM 127 and Omnirad TM 4817.

[0190] Based on the total weight of the UV-curable inkjet ink, the content of α-hydroxy ketone is preferably 1% to 10% by weight, more preferably 2% to 8% by weight, and even more preferably 3% to 6% by weight.

[0191] In a preferred embodiment, one or more acyl groups of the acylphosphine oxide photoinitiator or α-hydroxyketone photoinitiator are attached to a polymer or a polymerizable group.

[0192] Suitable polymeric acylphosphine oxide photoinitiators are disclosed in EP 2960303 A (FUJFILM).

[0193] Examples of suitable polymerizable α-hydroxyketone photoinitiators can be found in Esacure. TM The KIP150 was purchased from IGM RESINS.

[0194] 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.

[0195] In a particularly preferred embodiment of the UV-curable inkjet ink, the free radical photoinitiator comprises at least 4% by weight, preferably 5% to 15% by weight, of an acylphosphine oxide initiator, based on the total weight of the UV-curable ink. Good curability is achieved with this amount when UV-cured using a UV LED with a long wavelength greater than 360 nm.

[0196] Norrish type II photoinitiator

[0197] The free radical curable liquid and inkjet ink may contain a Norrish type II photoinitiator, which comprises a photoinitiating moiety selected from thioxanthone and benzophenone groups. Norrish type II photoinitiators containing thioxanthone groups are particularly preferred because they are beneficial for UV LED curing, especially for UV LEDs with emission wavelengths of at least 360 nm or even 370 nm.

[0198] However, free radical curable liquids and inkjet inks are preferably free of thioxanthone. The degradation products of thioxanthone after UV curing often impart an undesirable yellow tint to white or an undesirable green tint to cyan.

[0199] 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.

[0200] A specific example of a commercially available Norrish type II photoinitiator containing a thioxanthone group is Speedcure from Lambson. TM DETX (2,4-diethylthioxanone) and Speedcure TM ITX (2-isopropylthioxanthone), and Kayacure from Nippon Kayaku Co. TM DETX-S (2,4-Diethylthioxanone).

[0201] Suitable examples of Norrish type II 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.

[0202] A specific example of a commercially available Norrish type II photoinitiator containing a benzophenone group is Omnirad from IGMRESINS. TM 4MBZ and Omnirad TM BP, derived from Lambson's Speedcure TM PBZ and Speedcure TM 5040. The latter is a mixture of benzophenone and thioxanone.

[0203] Based on the total weight of the UV-curable inkjet ink, the content of the Norrish II photoinitiator, comprising a photoinitiating portion selected from thioxanthone and benzophenone groups, is preferably from 0.5% to 7.5% by weight, more preferably from 1% to 5% by weight. However, if the Norrish II photoinitiator is a polymerizable or polymerizable thioxanthone compound, its content can be higher based on the total weight of the UV-curable inkjet ink, preferably up to 25% by weight, more preferably up to 15% by weight.

[0204] Preferred examples of polymerizable Norrish type II photoinitiators comprising a photoinitiating moiety selected from thioxanthone or benzophenone groups are disclosed in EP 2161264 A (AGFA), EP 2199273 A (AGFA) and EP 2684876 A (AGFA).

[0205] Preferred examples of Norrish type II photoinitiators for polymerization comprising a photoinitiating moiety selected from thioxanone or benzophenone groups are disclosed in EP 1616920 A (AGFA) and EP 1616899 A (AGFA).

[0206] Commercial examples of polymerized thioxanone and benzophenone include Omnipol from IGM RESINS. TM BP, Omnipol TM TX and Omnipol TM 2702.

[0207] Co-initiator

[0208] To further enhance photosensitivity, UV-curable inkjet inks may contain additional co-initiators, also known as polymerization synergists, for which amine synergists are typically used.

[0209] Suitable examples of amine potentiators can be divided into three categories:

[0210] 1) Aliphatic tertiary amines, such as methyldiethanolamine, dimethylethanolamine, triethanolamine, triethylamine, and N-methylmorpholine;

[0211] (2) Aromatic amines, such as amyl p-dimethylaminobenzoate, 2-n-butoxyethyl 4-(dimethylamino)benzoate, ethyl 2-(dimethylamino)benzoate, ethyl 4-(dimethylamino)benzoate, and 2-ethylhexyl 4-(dimethylamino)benzoate; and

[0212] (3) (Meth)acrylate esterified amines, such as (meth)acrylate dialkylaminoalkyl esters (e.g., diethylaminoethyl acrylate) or (meth)acrylate N-morpholinoalkyl esters (e.g., N-morpholinoethyl acrylate).

[0213] UV-curable inkjet inks preferably contain a tertiary amine co-initiator, preferably a polymerizable or polymerizable tertiary amine co-initiator.

[0214] Preferred diffusion-hindered co-initiators are polymerizable co-initiators disclosed in paragraphs

[0088] and

[0097] of EP 2053101 A (AGFA).

[0215] Preferred diffusion-hindered co-initiators include polymerization co-initiators having a dendritic polymerization structure, more preferably a hyperbranched polymerization structure. Preferred hyperbranched polymerization co-initiators are those disclosed in US 2006014848 A (AGFA).

[0216] UV-curable inkjet inks preferably contain 0.1% to 15% by weight of the total inkjet ink, more preferably 0.5% to 10% by weight, and most preferably 1% to 8% by weight of a (diffusion-impeded) co-initiator.

[0217] Polymer inhibitors

[0218] Free radical curable liquids and inkjet inks may also contain polymerization inhibitors. Because of the presence of polymerization inhibitors in the inks, polymerization reactions before curing can be prevented, such as during storage or transportation.

[0219] Suitable polymerization inhibitors include phenolic antioxidants, hindered amine light stabilizers, phosphorescent antioxidants, benzoquinone, hydroquinone and its derivatives, such as hydroquinone monomethyl ether, which is commonly used in (meth)acrylate monomers.

[0220] Examples of phenol polymerization inhibitors include, but are not limited to, the following substances: 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.

[0221] Suitable commercially available inhibitors include, 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 TM20, derived from Rahn AG; Irgastab TM UV10 and Irgastab TM UV22, Tinuvin TM 460 and CGS20, obtained from Ciba Specialty Chemicals; Floorstab TM The UV series (UV-1, UV-2, UV-5, and UV-8) is derived from KromachemLtd; Additol TM The S series (S100, S110, S120 and S130) are from Cytec Surface Specialties.

[0222] The preferred polymerization inhibitor is Irgastab, obtained from BASF. TM UV10. Other examples of polymerization inhibitors include TEMPO, TEMPOL, and the Al copper-iron reagent.

[0223] Polymerization inhibitors can be used alone or in combination of two or more of them.

[0224] In a preferred embodiment, the polymerization inhibitor is a mixture of different types of polymerization inhibitors. Preferred polymerization inhibitors are mixtures of alkyl radical-based polymerization inhibitors, phenol-based polymerization inhibitors, and amine-based polymerization inhibitors. Suitable examples are given in EP 2851402 A (FUJIFILM).

[0225] The polymerization inhibitor is preferably present in an amount of 200 to 20,000 ppm relative to the total amount of inkjet ink. Below 200 ppm, undesirable polymerization is not adequately inhibited, while above 20,000 ppm, the curing rate is severely reduced.

[0226] surfactants

[0227] Free radical curable liquids and inkjet inks may contain surfactants. These surfactants may be anionic, cationic, nonionic, or amphoteric.

[0228] In a free radical curable liquid, the amount of surfactant present is preferably no more than 0.3% by weight, more preferably 0% to 0.2% by weight, based on the total weight of the free radical curable liquid. At higher concentrations, adhesion deteriorates rapidly.

[0229] In the coloring free radical curable inkjet ink, the total amount of surfactant is preferably less than 3% by weight based on the total weight of the ink, and more preferably less than 1.5% by weight based on the total weight of the free radical curable inkjet ink, to prevent the ink from foaming in its container. The surfactant content is preferably from 0.05% to 1.5% by weight, more preferably from 0.10% to 1.0% by weight, based on the total weight of the free radical curable inkjet ink.

[0230] 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 hydroxyl-functionalized, amine-modified, epoxy-modified, or other modified or combinations thereof. Preferred siloxanes are polymers, such as polydimethylsiloxane.

[0231] Preferred commercially available silicone surfactants include BYK from BYK Chemie. TM 333 and BYK TM UV3510 and Tegoglide obtained from EVONIK TM 410.

[0232] In a preferred embodiment, the surfactant is a polymerizable compound.

[0233] Preferred polymerizable silicone surfactants include (meth)acrylated silicone surfactants. Most preferably, (meth)acrylated silicone surfactants are acrylated silicone surfactants because acrylates are more reactive than methacrylates.

[0234] In a preferred embodiment, the (meth)acrylated silicone surfactant is a polyether-modified (meth)acrylated polydimethylsiloxane or a polyester-modified (meth)acrylated polydimethylsiloxane.

[0235] Preferred commercially available (meth)acrylated silicone surfactants include: silicone diacrylate Ebecryl TM 350, obtained from Cytec; polyether-modified acrylated polydimethylsiloxane BYK TM UV3500, BYK TM UV3510 and BYK TM UV3530; Polyester-modified acrylated polydimethylsiloxane BYK TM UV3570, entirely manufactured by BYK Chemie; Tego TM Rad 2100, Tego TM Rad 2200N, Tego TMRad 2250N, Tego TM Rad 2300, Tego TM Rad2500, Tego TM Rad 2600, Tego TM Rad 2700 and Tego TM RC711, entirely manufactured by EVONIK. Another preferred silicone is Silwet from OSI SPECIALITIES BENELUX NV. TM L7500; 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.

[0236] The preferred surfactant for free radical curable liquids is derived from SILTECH CORPORATION. Surfactants, such as ACR Di-1508.

[0237] Preparation of free radical curable inkjet inks

[0238] 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).

[0239] The average particle size and distribution of colored pigments are important characteristics of inkjet inks. Inkjet inks can be prepared by precipitating or grinding pigments in a dispersion medium in the presence of a dispersant.

[0240] Mixing equipment can include pressure kneaders, open kneaders, planetary mixers, dissolvers, and Dalton general-purpose mixers. Suitable grinding and dispersing equipment includes ball mills, pearl mills, colloid mills, high-speed dispersers, two-roll mills, bead mills, paint conditioners, and three-roll mills. Dispersions can also be prepared using ultrasonic energy.

[0241] Different types of materials can be used as abrasive media, such as glass, ceramics, metals, and plastics. In a preferred embodiment, the abrasive media may comprise particles, preferably substantially spherical in shape, such as beads composed substantially of polymer resin or yttrium-stabilized zirconia beads.

[0242] 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 largely eliminate photochemical radiation.

[0243] Inkjet inks can contain more than one pigment and can be prepared using separate dispersions for each pigment, or alternatively, several pigments can be mixed and co-ground to prepare a dispersion.

[0244] The dispersion process can be carried out in continuous, intermittent, or semi-intermittent modes.

[0245] The preferred amounts and ratios of the abrasive components will vary depending on the specific material and intended application. The contents of the abrasive mixture include abrasive particles and abrasive media. The abrasive particles contain pigments, polymeric dispersants, and liquid carriers. For inkjet inks, excluding the abrasive media, pigments are typically present in the abrasive particles in an amount of 5% to 50% by weight. The weight ratio of pigment to polymeric dispersant is preferably 20:1 to 1:2, more preferably 2:1 to 1:1.

[0246] The optimal grinding time can vary and depends on the selected pigment, mechanical means and residence conditions, initial and desired final particle size, etc. In this invention, pigment dispersions with an average particle size of less than 100 nm can be prepared.

[0247] After grinding, conventional separation techniques, such as filtration and sieving, are used to separate the grinding media from the ground particulate product (in dry or liquid dispersion form). Sieves are typically incorporated into the grinding mill, such as a bead mill. The ground pigment concentrate is preferably separated from the grinding media by filtration.

[0248] 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 inkjet printing systems. This technology allows for the self-preparation of larger quantities of colored inks. Through dilution, the inkjet ink is adjusted to the desired viscosity, surface tension, color, hue, saturation density, and print coverage for a specific application.

[0249] Inkjet printing method

[0250] An inkjet printing method for manufacturing decorative laminates according to a preferred embodiment of the present invention includes the following steps:

[0251] - Use the free radical curable inkjet inks colored with the ink kit described above to spray images onto thermoplastic substrates;

[0252] - Solidify the image;

[0253] - Apply the free radical curable liquid of the ink kit described above onto the image; and

[0254] -The free radical can solidify the liquid.

[0255] The thermoplastic substrate can be a cast polypropylene (cPP) film, a polyester (PET) film, or a polyvinyl chloride (PVC) film, and also includes biaxially oriented polypropylene (BOPP) film and biaxially oriented polyester (BOPET) film. However, PVC foil yielded the best adhesion results. The thickness of the thermoplastic foil is typically between 12 μm and 500 μm, and typically between 30 μm and 300 μm.

[0256] In a particularly preferred embodiment of the inkjet printing method, the thermoplastic substrate comprises polyvinyl chloride.

[0257] like Figure 2 .C and Figure 2 As shown in .D, if the free radical curable inkjet ink exhibits sufficient adhesion to the substrate, the substrate can replace one of the thermoplastic foils used in decorative laminates.

[0258] In a preferred embodiment of the inkjet printing method, a free radical curable liquid is applied by jetting.

[0259] In another preferred embodiment of the inkjet printing method, the free radical curable liquid is applied by a coating technique selected from spraying, scraping, extrusion coating, hopper coating, and curtain coating, or by a printing technique selected from flexographic printing, gravure printing, and offset printing.

[0260] In a particularly preferred embodiment, the inkjet printing method for manufacturing decorative laminates includes the following steps:

[0261] a) In a multi-pass printing process, images are jetted onto a thermoplastic substrate using free radical curable inkjet inks colored with the ink kit described above;

[0262] b) UV curing of the image using a UV LED with spectral emission in the 360 ​​to 400 nm range;

[0263] c) Apply the free radical curable liquid of the ink kit described above onto the image; and

[0264] d) The free radical curable liquid is UV-cured using a UV LED emitting light in the 360-400 nm range; wherein the free radical curable liquid is applied by a coating or printing technique other than inkjet printing. The coating technique is preferably selected from spraying, blade coating, extrusion coating, hopper coating, and curtain coating; and the printing technique is preferably selected from flexographic printing, gravure printing, and offset printing. The advantage of this inkjet printing method is that it maximizes the reliability and adhesion of inkjet printing in the manufacture of decorative laminates.

[0265] In another particularly preferred embodiment, the inkjet printing method for manufacturing decorative laminate materials includes the following steps:

[0266] a) In a multi-pass printing process, images are jetted onto a thermoplastic substrate using free radical curable inkjet inks colored with the ink kit described above;

[0267] b) Spray the free radical curable liquid of the ink kit described above onto the image; and

[0268] c) UV curing of coloring free radical-curable inkjet inks and free radical-curable liquids using UV LEDs with spectral emission in the 360-400 nm range. The advantages of this inkjet printing method are reduced investment costs and good adhesion. No additional equipment is needed to apply the free radical-curable liquid, as it can be applied using the printhead in the same multi-pass inkjet printer. In this case, the jetting and curing of the coloring free radical-curable inkjet ink and free radical-curable liquid are considered to occur simultaneously.

[0269] In yet another particularly preferred embodiment, the inkjet printing method for manufacturing decorative laminates includes the following steps:

[0270] a) In a single-pass printing process, an image is jetted onto a thermoplastic substrate using free radical curable inkjet inks colored with the ink kit described above;

[0271] b) UV curing of the image using a UV LED with spectral emission in the 360 ​​to 400 nm range;

[0272] c) Apply the free radical curable liquid of the ink kit described above onto the image; and

[0273] d) The free radical curable liquid is UV-cured using a UV LED emitting light in the 360-400 nm range; wherein the free radical curable liquid is applied by a coating or printing technique other than inkjet printing. The coating technique is preferably selected from spraying, blade coating, extrusion coating, hopper coating, and curtain coating; and the printing technique is preferably selected from flexographic printing, gravure printing, and offset printing. This inkjet printing method has the advantage of maximizing productivity and adhesion in the manufacture of decorative laminates.

[0274] Inkjet printing equipment

[0275] Free radical curable inkjet inks and free radical curable liquids can be sprayed onto an ink-receiving surface that moves relative to the printhead by one or more printheads that spray small droplets of ink through nozzles in a controlled manner.

[0276] A preferred printhead for inkjet printing systems is a piezoelectric printhead. Piezoelectric inkjet printing is based on the movement of a piezoelectric ceramic transducer when a voltage is applied. The applied voltage changes the shape of the piezoelectric ceramic transducer in the printhead, creating voids that are then filled with ink. When the voltage is removed again, the ceramic expands back to its original shape, ejecting ink droplets from the printhead. However, the inkjet printhead used in this invention is not limited to a piezoelectric inkjet printhead. Other inkjet printheads can be used, and they include various types such as continuous, electrostatic, and acoustic on-demand ink droplets.

[0277] The preferred piezoelectric printhead is the so-called push-mode piezoelectric printhead, which has a relatively large piezoelectric element that is also capable of ejecting more viscous ink droplets. Such a printhead is available from RICOH as the GEN5s printhead.

[0278] In a preferred embodiment, the piezoelectric printhead is a so-called through-flow piezoelectric on-demand ink drop printhead. Such printheads are available from TOSHIBA TEC as CF1ou printheads. Through-flow printheads are preferred because they improve the reliability of inkjet printing, which is important in industrial environments.

[0279] In a preferred embodiment, inkjet printing is performed using a multi-pass inkjet printing apparatus. In such an apparatus, the inkjet printhead moves back and forth across the ink-receiving surface in the lateral direction. For high area throughput, bidirectional printing is preferred. The colored radical-curable inkjet ink and radical-curable liquid can be printed in a parallel printing mode or a two-step printing mode. In the parallel printing mode, the radical-curable inkjet ink and radical-curable liquid are simultaneously sprayed and cured, while in the two-step printing mode, the radical-curable inkjet ink is sprayed and cured first, and only after the radical-curable inkjet ink has cured is the radical-curable liquid sprayed onto the cured colored radical-curable inkjet ink and cured thereafter.

[0280] Parallel printing offers advantages in productivity but is slightly inferior to two-step printing in terms of adhesion. Two-step printing is preferred when excellent adhesion results are required.

[0281] In another preferred embodiment, the coloring free radical curable inkjet ink is printed in a so-called "single-pass printing process," which can be achieved using a page-width inkjet printhead or multiple staggered inkjet printheads covering the entire width of the inked surface. During a single-pass printing process, the inkjet printhead typically remains stationary, and the inked surface is conveyed beneath the printhead.

[0282] Decorative laminates are typically larger than 2m in width, which increases the cost of single-pass inkjet printers because a large number of printheads covering the entire width of the ink-receiving surface must be anticipated for each color.

[0283] Therefore, in a preferred embodiment of the single-pass printing process, the free radical curable liquid is not applied by jetting from a printhead, but rather by a cheaper coating or printing technique. Preferred coating techniques for applying the free radical curable liquid are selected from spraying, blade coating, extrusion coating, 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.

[0284] In another preferred embodiment of multi-pass inkjet printing, radical-curable inkjet ink is printed using a multi-pass inkjet apparatus, while the radical-curable liquid is applied via a coating or printing technique. The same coating and printing techniques mentioned for single-pass printing processes are preferably used in combination with a multi-pass inkjet apparatus.

[0285] In the most preferred embodiment, inkjet printing of free radical curable inkjet inks, especially UV curable inkjet inks, is performed in a multi-pass printing mode. Multi-pass printing is a technique used to reduce banding in inkjet printing. When ink droplets are still in liquid form, they tend to flow together due to surface tension. This is called coalescence. For printing high-quality images, it is important to print individual dots. However, to achieve fully saturated colors, the dots must overlap to completely cover the substrate. Coalescence can be largely avoided by printing only a portion of the image data to avoid printing adjacent dots simultaneously during each printing cycle. In addition, by avoiding all horizontally adjacent portions, the lateral speed of the printing mechanism can be increased to twice the rated printing speed of the print head. In the preferred embodiment, the number of passes used is 2 to 6, more preferably no more than 4.

[0286] Another advantage of using multi-pass printing is that UV-curable inkjet inks are cured continuously in a single pass, rather than in a single pass, which would require a curing unit with high UV output. Multi-pass printing also results in a longer printhead lifespan. While in single-pass printing, one side emitter is sufficient to replace the entire printhead, in multi-pass printing, many side emitters can be accommodated, and even failures can be tolerated. Furthermore, multi-pass printing presses for printing wide-format substrates are generally much less expensive than single-pass inkjet units.

[0287] Curing device

[0288] Free radicals can cure inkjet inks and liquids through photochemical radiation.

[0289] In one implementation, photochemical radiation is provided by an electron beam device. One advantage of electron beam curing is that no photoinitiating system is required in radical-curable inkjet inks and liquids, making manufacturing more economical once the investment in electron beam curing is made.

[0290] The preferred electron beam device is a low-energy electron beam source that applies a dose not exceeding 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 the shielding material. Most preferably, it uses about 3 mm of lead or about 20 mm of stainless steel.

[0291] In another, more preferred embodiment, photochemical radiation is provided by a UV curing device.

[0292] In multi-pass inkjet printing, the curing unit can be arranged in combination with the printhead of the inkjet printer and moved with it so that the free radical curable composition is quickly exposed to UV curing radiation after jetting.

[0293] Any ultraviolet 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, ultraviolet LEDs, ultraviolet lasers, and flashes. Among these, sources exhibiting a relatively long wavelength UV contribution with a dominant wavelength of 300-400 nm are preferred. Specifically, UV-A sources are preferred due to their more efficient internal curing caused by reduced light scattering.

[0294] UV radiation is typically categorized as UV-A, UV-B, and UV-C as follows:

[0295] • UV-A: 400nm to 320nm

[0296] • UV-B: 320nm to 290nm

[0297] • UV-C: 290nm to 100nm.

[0298] Most preferably, UV LEDs with spectral emission between 345-420 nm, more preferably between 360 nm and 400 nm, are used for UV curing. These UV LEDs have a very long lifespan 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.

[0299] To facilitate UV curing, inkjet printers may include one or more oxygen-consuming units. To reduce the oxygen concentration in the curing environment, the oxygen-consuming units are arranged with layers of nitrogen or other relatively inert gases (e.g., CO2) in adjustable positions and with adjustable inert gas concentrations. Residual oxygen levels are preferably kept as low as 200 ppm, but can be in the range of 200 ppm to 1200 ppm.

[0300] Decorative laminate

[0301] The decorative laminate is manufactured from a first thermoplastic foil with an image inkjet-printed using the aforementioned ink kit as described above by further comprising the following steps: combining a second thermoplastic foil with the first thermoplastic foil, wherein the image on the first thermoplastic foil faces the second thermoplastic foil; and 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.

[0302] In a preferred embodiment of the decorative laminate, the first and second thermoplastic foils comprise polyvinyl chloride. These thermoplastic sheets exhibit excellent water resistance and, when used with them, excellent adhesion is achieved using the coloring of free radical-curable inkjet inks and free radical-curable liquids from the ink kit described above.

[0303] Decorative laminate materials are cut into decorative laminates. These decorative laminates preferably have tongues and grooves for similar glue-free interlocking. The tongues and grooves are formed in a specific manner, such as... Figure 1 As shown in the example, decorative panels can "interlock" with each other. The polymerizable composition of colored, free-radical curable inkjet inks and free-radical curable liquids allows for this molding, and no cracks are shown in the image.

[0304] Decorative layer

[0305] The decorative layer comprises a colored pattern printed with colored free radical-curable inkjet ink and an adhesive layer on 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 can be applied directly to the base layer (see .B). Figure 1 .C and Figure 1 .D).

[0306] There are no practical limitations on the content of colored images. Colored images can also contain information such as text, arrows, and logos. Unlike gravure printing, inkjet printing has the advantage of being able to print this information in low volumes without additional cost.

[0307] In a preferred embodiment, the colored image is a wood or stone replica, but it can also be a fantastical or creative image, such as an ancient world map or geometric pattern, or even a single color, used to manufacture, for example, a floor made of black and red tiles or a single-color furniture door.

[0308] The advantage of printing wood color images is that, in addition to oak, pine, and beech, it can also imitate very expensive woods that are not usually used for home decoration, such as black walnut.

[0309] The advantage of printing stone-colored images is that it can create flooring that is an accurate imitation of stone flooring, but without the cold feeling when walking barefoot on it and can be easily replaced according to fashion over time.

[0310] protective layer

[0311] The top surface of decorative panels is typically a transparent thermoplastic foil that forms a protective layer. Figure 2 (11) However, an additional finishing layer can be applied over the protective layer.

[0312] In a preferred embodiment, an antistatic layer is applied over the protective layer. Techniques for making decorative laminates antistatic are well known in the field of decorative laminates, as illustrated by EP 1567334 A (FLOORING IND).

[0313] In a particularly preferred embodiment, the decorative panel has a polyurethane finish layer on the protective layer.

[0314] The top surface of the decorative panel (i.e., at least the protective layer) is preferably provided with an embossed pattern that matches the colored pattern, such as wood grain, cracks, and knots in wood prints. Embossing techniques for achieving this embossing are well-known in the flooring industry and are disclosed, for example, by EP 1290290 A (FLOORING IND), US 2006144004 (UNILIN), EP 1711353 A (FLOORING IND), and US 2010192793 (FLOORING IND).

[0315] Most preferably, the embossing is formed by pressing a digital embossed sheet against a transparent thermoplastic foil that forms a protective layer during hot pressing. The digital embossed sheet is a sheet including raised portions that can be used to form an embossing on the decorative panel by pressing the digital embossed sheet against the protective layer of the decorative panel. The sheet is preferably rigid and made of metal or hard plastic.

[0316] An alternative to digital embossing panels can be digital embossing rollers, which are rollers that include raised sections to form an embossing on the decorative panel. The embossing is applied to the protective layer of the decorative panel by pressing the digital embossing roller against it and rotating it, preferably using heat.

[0317] The finishing layer, preferably a polyurethane finishing layer, may include hard particles, such as corundum, to prevent scratches on the top surface. The total amount of hard particles is preferably 1 g / m³. 2 With 100g / m 2 Between, preferably 2g / m 2 Up to 50g / m 2 .

[0318] Preferred hard particles are ceramic or mineral particles selected from alumina, 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. 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-mentioned hard particles can also be applied.

[0319] The amount of hard particles can be determined based on the required scratch resistance.

[0320] Hard particles with an average particle size between 1 μm and 200 μm are preferred. Preferably, a 1 g / m² concentration is applied over the printed pattern. 2 With 40g / m 2 These types of particles, in quantities between 20 g / m³, are considered to be below 20 g / m³. 2The quantity can meet the requirements for lower quality.

[0321] The transparent thermoplastic foil used as the protective layer preferably has a thickness greater than 100 μm, more preferably 300 μm to 700 μm. The thermoplastic foil is transparent, allowing the colored pattern of the decorative layer to be observed.

[0322] grassroots

[0323] In a preferred embodiment, the decorative panel includes a base layer. The base layer provides sufficient rigidity to the decorative panel so that the panel will not break when, for example, a long rectangular decorative panel bends under its own weight. For this purpose, the base layer is preferably fiber-reinforced.

[0324] In a preferred embodiment, the base layer substantially comprises polyvinyl chloride and reinforcing fibers. More preferably, the base layer substantially comprises polyvinyl chloride and glass fiber.

[0325] The base layer can consist of two foils with fiberglass wool inserted.

[0326] The base layer may contain minerals. Talc or calcium carbonate (chalk), alumina, and silica are particularly suitable in this study. The base layer may contain flame retardants.

[0327] In a particularly preferred embodiment, the base layer is a plasticized PVC film containing 10%-50% by weight of filler material, preferably mainly calcium carbonate; and / or 2%-20% by weight, preferably 10%-20% by weight of titanium dioxide; and / or 2%-20% by weight, preferably between 10%-20% by weight of softening polymer, particularly PLA, PMMA or PVAC.

[0328] The base layer can also be a so-called wood-plastic composite (WPC), preferably containing one or more polymers or copolymers selected from polypropylene, polyethylene and polyvinyl chloride.

[0329] When the substrate contains one or more polymers or copolymers selected from polypropylene, polyethylene, and polyvinyl chloride, the substrate can be considered as one of the first and second thermoplastic foils representing the manufacturing method and decorative laminate of the present invention.

[0330] Example

[0331] Material

[0332] Unless otherwise specified, all materials used in the following examples are obtained from standard sources such as Sigma-Aldrich (Belgium) and Acros (Belgium).

[0333] PB15:4 is an abbreviation for CI Pigment Blue 15:4 pigment, which can be found in CLARIANT. BlueP-BFS was obtained.

[0334] S35000 is used for SOLSPERSE TM The abbreviation 35000 is from LUBRIZOL, a polyethyleneimine-polyester superdispersant.

[0335] DB162 is used as a polymer dispersant. The abbreviation 162 is available from BYK CHEMIE GMBH, which removes the solvent mixture of 2-methoxy-1-methylethyl acetate, xylene, and n-butyl acetate. The polymer dispersant is a polyester-polyurethane dispersant based on caprolactone and toluene diisocyanate, with an amine value of 13 mg KOH / g, Mn of approximately 4,425, and Mw of approximately 6,270.

[0336] EFKA is a polyacrylate dispersant, available from BASF. 7701 was obtained.

[0337] PCA-2 is N-vinylcaprolactam, available from BASF BELGIUM, NV.

[0338] PCA-6 was prepared as described in Preparation Example 1 on pages 21-22 of WO 2018 / 146259 (BASF).

[0339] PCB-1 is tetrahydrofurfuryl acrylate, available from ARKEMA. SR285 obtained.

[0340] CE-1 is (3-ethyl-3-oxetane)methacrylate, which is available from KOWA EUROPE GMBH as OXE-10.

[0341] IBOA is isobornyl acrylate, available from ARKEMA. SR506D obtained.

[0342] IDA is isodecyl acrylate, which can be obtained from SARTOMER. Obtained from SR395.

[0343] PEA is 2-phenoxyethyl acrylate, available from ARKEMA. SR339C obtained.

[0344] CTFA is a cyclic trimethylolpropane-formaldehyde acrylate, available from ARKEMA. SR531 obtained.

[0345] SR504D is ethoxylated nonylphenol acrylate, available from ARKEMA. SR506D obtained.

[0346] TBCH is 4-tert-butylcyclohexyl acrylate, available from ARKEMA under the trade name. Obtained from CD217.

[0347] ACMO is acryloylmorpholine, which can be obtained from RAHN.

[0348] SR833S is tricyclodecanediethanol diacrylate, available from ARKEMA. SR833s obtained.

[0349] DPGDA is dipropylene glycol diacrylate, available from BASF. DPGDA obtained.

[0350] HDDA is 1,6-hexanediol diacrylate, available from ARKEMA. SR238 obtained.

[0351] VEEA is 2-(2'-ethoxyethoxy)ethyl acrylate, a difunctional monomer, which is available from NIPPONSHOKUBAI, Japan.

[0352] MPDA is 3-methyl-1,6-pentanediol diacrylate, which can be obtained from ARKEMA. SR341 obtained.

[0353] TMPTA is trimethylolpropane triacrylate, available from ARKEMA. SR351 obtained.

[0354] SR9035 is an ethoxylated (15)trimethylolpropane triacrylate containing fifteen ethoxy units, with a molecular weight of 956, and can be obtained from SARTOMER. SR9035 obtained.

[0355] G4215 is an aliphatic polyester urethane acrylate, available from RAHN. 4215 was obtained.

[0356] G1122 is a monofunctional urethane acrylate ester, available from RAHN. 1122 obtained.

[0357] CN963B80 is a urethane diacrylate, available from ARKEMA.

[0358] CN963B80 was obtained.

[0359] CN3755 is a diacrylate co-initiator, available from ARKEMA. CN3755 was obtained.

[0360] CN3715 is a diethylamine Michael adduct of ethoxylated trimethylolpropane triacrylate, a co-initiator, available from ARKEMA. CN3715 was obtained.

[0361] TPO is 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, produced by IGM RESINS. TPO obtained.

[0362] TPO-L is an acylphosphine oxide photoinitiator derived from IGM RESINS. TPO-L obtained.

[0363] BAPO is a diacylphosphine oxide photoinitiator derived from IGM RESINS. 819 was obtained.

[0364] ITX is a mixture of isomers of 2-isopropylthioxanthone and 4-isopropylthioxanthone, derived from IGM RESINS. ITX obtained.

[0365] BP from IGM RESINS with Omnirad TM BP obtained.

[0366] DETX is a thioxanthone photoinitiator that can be obtained from RAHN. DETX obtained.

[0367] EPD is ethyl 4-dimethylaminobenzoate, available from RAHN AG. EPD obtained.

[0368] EHA is 2-ethylhexyl 4-dimethylaminobenzoate, which can be obtained from RAHN. EHA obtained.

[0369] INHIB is a form based on Table 4 A mixture of polymerization inhibitors.

[0370] Table 4

[0371] Components weight% DPGDA 82.4 p-Methoxyphenol 4.0 BHT 10.0 <![CDATA[Cupferron TM AL]]> 3.6

[0372] BHT is an abbreviation for 2,6-di-tert-butyl-4-methylphenol (CASRN128-37-0), derived from ALDRICHCHEMICAL CO.

[0373] AL is N-nitrosophenylhydroxylamine aluminum, obtained from WAKO CHEMICALS LTD.

[0374] UV10 is 4-hydroxy-2,2,6,6-tetramethylpiperidinoxy sebacate, available from BASF. UV10 was obtained.

[0375] UV3510 is a polyether-modified polydimethylsiloxane wetting agent, available from BYK CHEMIE GMBH. TM UV3510 was obtained.

[0376] T410 is a surfactant available from EVONIK as Tegoglide. TM 410 was obtained.

[0377] L7500 is a silicone surfactant available from MOMENTIVE PERFORMANCES. L7500 obtained.

[0378] SILMER is a difunctional silicone acrylate prepolymer available from SILTECH CORPORATION. ACR Di-1508 was obtained.

[0379] SILWAX is a polysiloxane surfactant available from SILTECH CORPORATION. B116 was obtained.

[0380] P2 is an 80μm thick opaque white polyvinyl chloride foil.

[0381] C3 is a 500μm thick transparent polyvinyl chloride foil.

[0382] Measurement methods

[0383] 1. Adhesion

[0384] Adhesion is determined by testing peel strength. The test uses 180° geometry and follows the EN431:1994 standard, and is conducted using… The tensile testing was performed. The tensile testing 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 average load / width between 10 mm and 80 mm. The results were reported in N / 5 cm.

[0385] Good adhesion requires a minimum peel strength of 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.

[0386] 2. Viscosity

[0387] Using a HAAKE Rotovisco 1 rotational rheometer at 45°C and 1000s... -1 The viscosity of the sample was measured at a certain shear rate.

[0388] 3. Adhesion

[0389] The adhesion of the sample was tested by rubbing a clean cotton swab on the surface after curing.

[0390] Based on whether there are traces left by cotton swabs, according to Table 5 Evaluate adhesion.

[0391] Table 5

[0392]

[0393] Example 1

[0394] This example illustrates the effect of the amount of monofunctional polymerizable compound A or B on adhesion in a polymerizable composition of a free radical curable liquid.

[0395] Preparation of Cyan Pigment Dispersion

[0396] Using DISPERLUX SARL, Luxembourg TM Disperser, through mixing according to Table 6 The cyan pigment dispersion was prepared by grinding the components for 30 minutes. The dispersion was then ground using a Bachofen DYNOMILL ECM mill filled with 0.4 mm yttrium-stabilized zirconia beads (from TOSOH Co.'s "High Abrasion-Resistant Zirconia Grinding Media"). The mixture was circulated in the mill for 2 hours. After grinding, the pigment dispersion was discharged into a container through a 1 μm filter.

[0397] Table 6

[0398] Components weight% PB15:4 16.00 S35000 16.00 INHIB 1.00 DPGDA 67.00

[0399] Preparation of free radical curable inkjet ink C-1

[0400] By mixing the cyan pigment dispersion and according to Table 7 The components were used to prepare cyan free radical UV-curable inkjet ink C-1. Weight percentages are based on the total weight of the inkjet ink.

[0401] Table 7

[0402]

[0403]

[0404] The polymerizable composition of Cyan free radical UV curable inkjet ink C-1 contains 67% by weight of a monofunctional polymerizable compound based on the total weight of the inkjet ink.

[0405] Preparation of free radical curable liquids L-1 to L-8

[0406] By mixing Table 8 The components were used to prepare free radical curable liquids L-1 to L-8. The amounts of all compounds are expressed as a weight percentage based on the total weight of the free radical curable liquid.

[0407] Table 8

[0408]

[0409]

[0410] Manufacturing of laminated materials

[0411] Cyan free radical curable inkjet ink C-1 was applied to the matte side of thermoplastic foil P2 at a thickness of 10 μm and cured at a speed of 20 m / min using a Fusion DRSE-120 conveyor belt equipped with a 12W 395nm LED. The maximum output of the lamp was 1.05 J / cm². 2 And the peak intensity is 5.6 W / cm². 2 .

[0412] Each free radical curable liquid L-1 to L-8 was then coated with a thickness of 10 μm onto a thermoplastic foil P2 provided with curable ink C-1, and cured at a speed of 20 m / min using a Fusion DRSE-120 conveyor belt equipped with a 12W 395nm LED.

[0413] Then, by bringing the ink layer on foil P2 towards the transparent thermoplastic foil C3, each of the thermoplastic foils P2, which provides curable ink C-1 and curable free radical curable liquid, is combined with the transparent thermoplastic foil C3. As another comparison, by bringing the ink layer on foil P2 towards the transparent thermoplastic foil C3, a thermoplastic foil P2, which provides curable ink C-1 but no curable free radical curable liquid, is combined with the transparent thermoplastic foil C3. The components of foils P2 and C3 are then hot-pressed for 160 seconds at a temperature of 160°C and a pressure of 14 bar in an OLAH6 laminator from OASYS.

[0414] Evaluation and Results

[0415] The adhesion (peel strength) of the hot-pressed samples was evaluated. The results are shown in... Table 9 The measured viscosity of free radical-curable liquids is also shown.

[0416] Table 9

[0417]

[0418]

[0419] from Table 9 It is evident that the adhesion obtained using free radical curable liquids L-1, L-2, and L-8 is insufficient. 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 free radical curable liquid L-8 contains less than 15% by weight of the polyfunctional polymerizable compound.

[0420] For the free radical curable liquids L-4 to L-7, desired viscosities of 5 to 15 mPa·s were obtained at 45°C for spraying. Free radical curable liquid L-3 also yielded satisfactory adhesion results and could still be sprayed at temperatures slightly above 45°C.

[0421] Example 2

[0422] This embodiment illustrates the effect of the amount of polyfunctional polymerizable compound and monofunctional polymerizable compound A or B on the adhesion in a polymerizable composition of a free radical curable liquid.

[0423] Free radical curable inkjet ink

[0424] Example 2 also uses the same cyan free radical UV curable inkjet ink C-1 as Example 1.

[0425] Preparation of free radical curable liquids

[0426] By mixing Table 10 The components were used to prepare free radical curable liquids L-9 to L-13. The amounts of all compounds are expressed as a weight percentage based on the total weight of the free radical curable liquid.

[0427] Table 10

[0428]

[0429]

[0430] Manufacturing of laminated materials

[0431] The laminate was 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.

[0432] Evaluation and Results

[0433] The adhesion (peel strength) of the hot-pressed samples was evaluated. The results are shown in... Table 11 The measured viscosity of free radical-curable liquids is also shown.

[0434] Table 11

[0435]

[0436] Table 11 The study demonstrates insufficient adhesion obtained using radical-curable liquid L-9, which does not contain monofunctional polymerizable compounds A or B. Compound CE-1 is similar to monofunctional polymerizable compound B, except that it contains a quaternary heterocycle with a single ether group instead of a five- to seven-membered saturated heterocycle. Good adhesion is obtained using radical-curable liquids L-10 to L-12, which contain sufficient amounts of monofunctional polymerizable compounds A and polyfunctional polymerizable compounds.

[0437] For the free radical curable liquids L-10 to L-11, a desired viscosity of 5 to 15 mPa·s at 45°C was obtained for spraying the free radical curable liquid. The free radical curable liquid L-12, which provides satisfactory adhesion results, can be sprayed at temperatures above 45°C. Alternatively, a portion of the higher viscosity SR833S (140 mPa·s at 25°C) can be replaced with the lower viscosity DPGDA (9 mPa·s at 25°C).

[0438] Example 3

[0439] This example illustrates the effect of other polymerizable compounds in free radical curable liquids on adhesion.

[0440] Free radical curable inkjet ink

[0441] Example 3 also uses the same cyan free radical UV curable inkjet ink C-1 as Example 1.

[0442] Preparation of free radical curable liquids

[0443] By mixing Table 12 to Table 14 The radical-curable liquids COMP-1 to COMP-5 and INV-1 to INV-14 were prepared from the components. The amounts of all compounds are expressed as a weight percentage based on the total weight of the radical-curable liquids.

[0444] Table 12

[0445]

[0446]

[0447] Table 13

[0448]

[0449] Table 14

[0450]

[0451] Manufacturing of laminated materials

[0452] The laminate was 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.

[0453] Evaluation and Results

[0454] The adhesion (peel strength) of the hot-pressed samples was evaluated. The results are shown in... Table 15 The adhesive properties of free radical-curable liquids were also demonstrated.

[0455] Table 15

[0456]

[0457]

[0458] Free radical curable liquids COMP-1 to COMP-5 do not achieve good adhesion, even if some are tacky. According to EP 3173229 A (TARKETT), the latter would be advantageous, as this patent discloses improved adhesion with incompletely cured UV-curable inks. In industrial environments, UV-cured compositions that do not exhibit tackiness are preferred for reliable manufacturing without the vulnerability to dust or scratches.

[0459] The free radical curable liquids INV-1 and INV-2 showed that increasing the amount of surfactant negatively impacts adhesion. Therefore, it is preferable to use a surfactant amount of no more than 0.3% by weight based on the ink, as this concentration allows for achieving the desired surface tension for good spreading.

[0460] Comparative Example 2 contains CTFA, which differs from the monofunctional polymerizable compound B according to formula (2) in that it contains two ether functional groups in a six-membered saturated heterocycle. Example INV-3 of the present invention shows that CTFA can still be contained in a radical curable liquid when polymerizable compounds A or B (here: PCA-2) are present.

[0461] A comparison of examples COMP-3 to COMP-5 with INV-4 to INV-14 shows that, provided there are sufficient monofunctional polymerizable compounds A or B and polyfunctional polymerizable compounds, various other monofunctional and polyfunctional polymerizable compounds can be included in radical-curable liquids, where they have an acceptable effect on adhesion.

[0462] Example 4

[0463] This embodiment illustrates the effect of the amount of polyfunctional polymerizable compound and monofunctional polymerizable compound A or B on the adhesion in a polymerizable composition of a free radical curable liquid.

[0464] Free radical curable inkjet ink

[0465] Example 4 also uses the same cyan free radical UV curable inkjet ink C-1 as Example 1.

[0466] Preparation of free radical curable liquids

[0467] By mixing Table 16 The free radical curable liquids COMP-6 and INV-15 to INV-17 were prepared from the components. The amounts of all compounds are expressed as a weight percentage based on the total weight of the free radical curable liquids.

[0468] Table 16

[0469]

[0470] Manufacturing of laminated materials

[0471] The laminate was 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.

[0472] Evaluation and Results

[0473] The adhesion (peel strength) of the hot-pressed samples was evaluated. The results are shown in... Table 17 The adhesive properties of free radical-curable liquids were also demonstrated.

[0474] Table 17

[0475]

[0476]

[0477] from Table 17 As can be seen, compared with the free radical curable liquids INV-15 to INV-17, the free radical curable liquid COMP-6 failed to achieve good adhesion. The latter three free radical curable liquids also did not exhibit any adhesion.

[0478] Example 5

[0479] This embodiment illustrates the effect of the amount of monofunctional and polyfunctional polymerizable compounds on adhesion in polymerizable compositions of free radical curable inkjet inks.

[0480] Preparation of free radical curable inkjet inks

[0481] 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 construct radical-curable inkjet inks, which exhibited good UV curing and reliable jetting properties. This was achieved by mixing the cyan pigment dispersions and according to… Table 18 The components were used to prepare cyan free radical UV-curable inkjet inks COMP-7, COMP-8, and INV-18 to INV-24. Weight percentages are based on the total weight of the inkjet inks.

[0482] Table 18

[0483]

[0484]

[0485] Preparation of free radical curable liquids

[0486] By mixing Table 19 The components were used to prepare the radical-curable liquid FRCL. The amounts of all compounds are expressed as a weight percentage based on the total weight of the radical-curable liquid.

[0487] Table 19

[0488] Compound weight %: FRCL PCA-2 37.9 IBOA 10.0 TPO 8.0 SR833S 39.0 CN3755 4.0 INHIB 1.0 SILMER 0.1

[0489] Manufacturing of laminated materials

[0490] The laminate was prepared in the same manner as in Example 1, except that the cyan free radical UV curable inkjet inks COMP-7, COMP-8 and INV-18 to INV-24 and the free radical curable liquid FRCL were used instead of the free radical curable inkjet inks C-1 and L-1 to L-8, respectively.

[0491] Evaluation and Results

[0492] The adhesion (peel strength) of the hot-pressed samples was evaluated. The results are shown in... Table 20 middle.

[0493] Table 20

[0494]

[0495]

[0496] from Table 20 It should be understood that good adhesion cannot be obtained with inkjet inks COMP-7 and COMP-8, which are polymerizable compositions containing no 10% to 90% by weight of one or more monofunctional polymerizable compounds. Optimal adhesion results are obtained when the polymerizable composition of the free radical curable inkjet ink contains 40% to 80% by weight of one or more monofunctional polymerizable compounds.

[0497] By comparing the adhesion results of the free radical curable inkjet ink INV-24 with those of the free radical curable inkjet inks INV-22 and INV-23, degradation can be observed when the inkjet ink contains a multifunctional polymerizable compound with more than two polymerizable groups.

[0498] Example 6

[0499] This embodiment illustrates a practical implementation using an inkjet printer. Examples 1 through 5 are performed using a doctor blade coating machine because it is faster and cheaper.

[0500] Free radical curable inkjet inks

[0501] Uses a commercial CMYK inkjet ink kit obtained from AGFA. 1550. All inkjet inks are colored, free-radical curable inkjet inks comprising colored pigments and polymerizable compositions, wherein the polymerizable compositions contain, particularly preferably, a monofunctional polymerizable compound in the range of 40% to 80% by weight based on the total weight of the polymerizable compositions.

[0502] Preparation of free radical curable liquids

[0503] By mixing Table 21 The free radical curable liquid FRCL-2 was prepared from the components. The amounts of all compounds are expressed as a weight percentage based on the total weight of the free radical curable liquid.

[0504] Table 21

[0505]

[0506]

[0507] At 45℃ and 1,000s -1 The viscosity measured at the shear rate was 10 mPa·s.

[0508] Manufacturing of laminated materials

[0509] Create a composite image that includes a landscape photograph, a photograph of two children, and rectangles in cyan, magenta, yellow, black, red, blue, and green.

[0510] Used from AGFA H 2050i LED and Inkjet Ink Kit 1550 images were printed on 80μm thick opaque white PVC foil P2. Printing parameters were set as follows: 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 scraping and quality = 720×720 dpi. The print images and rectangles were large enough to allow for peel strength testing of each.

[0511] The free radical curable liquid FRCL-2 was applied in different ways. In sample IJ-1, a 10 μm thick layer of free radical curable liquid FRCL-2 was applied to the top of an inkjet-printed image using a squeegee. This allowed for direct comparison with the results of Examples 1 to 5.

[0512] In samples IJ-2 and IJ-3, printing with both free radical curable inkjet ink and free radical curable liquid FRCL-2 was performed simultaneously. While in sample IJ-2 the printed image was completely (100%) covered by the free radical curable liquid FRCL-2, in sample IJ-3 the printed image was partially not covered by FRCL-2, resulting in the ink contacting up to 25% of the surface area of ​​the second thermoplastic sheet C2 during lamination.

[0513] In samples IJ-4 and IJ-5, printing was performed in two steps. First, a radical-curable inkjet ink was sprayed and cured. Then, the printed image was reintroduced into the inkjet printer, and a radical-curable liquid FRCL-2 was sprayed onto the printed image and cured. Samples IJ-4 and IJ-5 were printed with the 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.

[0514] Then, by aligning the image on foil P2 with the transparent thermoplastic foil C3, each of samples IJ-1 to IJ-5 was combined with the transparent thermoplastic foil C3. The assembly of foils P2 and C3 was then hot-pressed for 40 seconds at a temperature of 160°C and a pressure of 14 bar.

[0515] Evaluation and Results

[0516] The adhesion (peel strength) of hot-pressed samples IJ-1 to IJ-5 was evaluated. The average results of peel tests performed on photographs and colored rectangles are shown below. Table 22 middle.

[0517] Table 22

[0518]

[0519] from Table 22 As can be seen, the results of the doctor blade coating can be compared with the results obtained through actual inkjet printing experiments.

[0520] It can also be seen that the adhesion results of the two-step printing method are slightly better than the adhesion structure of the parallel printing method.

[0521] Finally, it can be seen that if the colored free radical curable inkjet ink is not completely covered by the free radical curable liquid, the adhesion deteriorates.

[0522] List of reference numerals

[0523] Table 23

[0524]

[0525]

Claims

1. An ink kit for manufacturing decorative laminates, comprising a coloring free radical curable inkjet ink and a free radical curable liquid. The coloring free radical curable inkjet ink comprises a colored pigment and a polymerizable composition, wherein the polymerizable composition contains 10% to 90% by weight of one or more monofunctional polymerizable compounds. The free radical curable liquid comprises a polymerizable composition containing 20% ​​by weight or more of a multifunctional polymerizable compound and 20% by weight or more of a monofunctional polymerizable compound A or B. All weight percentages (%) are based on the total weight of the polymerizable composition in the coloring radical-curable inkjet ink or the polymerizable composition in the radical-curable liquid. Among them, the monofunctional polymerizable compound A is a compound according to formula (1): Where R represents hydrogen or methyl; X represents oxygen or NR'- group; L represents a divalent linker having no 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 alkylaryl, and substituted or unsubstituted aryl or heteroaryl; n represents 0 or 1; and A represents a portion according to formula (1A): Where Q represents the atoms necessary for the formation of five- to eight-membered rings, and the dashed lines represent covalent bonds to carbon atoms; and Among them, the monofunctional polymerizable compound B is a compound according to formula (2): Where R2 represents hydrogen or methyl; L represents a divalent linker with no more than 10 carbon atoms; n represents 0 or 1; and D represents a five- to seven-membered saturated heterocycle containing a single ether group. The free radical curable liquid comprises a polymerizable composition containing 30% by weight or more of a multifunctional polymerizable compound; or The free radical curable liquid comprises a polymerizable composition containing 24% by weight or more of a monofunctional polymerizable compound A or B.

2. The ink kit according to claim 1, wherein the free radical curable liquid contains a multifunctional polymerizable compound selected from dipropylene glycol diacrylate, tricyclodecanediethanol diacrylate, and 1,6-hexanediol diacrylate.

3. The ink kit according to claim 1, wherein the polymerizable compound A or B is selected from:

4. The ink kit of claim 1, wherein the free radical curable liquid contains a surfactant in an amount not exceeding 0.3% by weight based on the total weight of the free radical curable liquid.

5. The ink kit according to claim 1, wherein the free radical curable liquid is cured at 45°C for 1,000 seconds. -1 It has a viscosity between 5 mPa·s and 15 mPa·s at a shear rate.

6. The ink kit of claim 1, wherein the free radical curable liquid contains a polymerizable composition, and based on the total weight of the polymerizable composition, the polymerizable composition contains 20% by weight or more of a multifunctional polymerizable compound and 30% by weight or more of a monofunctional polymerizable compound A or B.

7. The ink kit of claim 1, wherein the one or more coloring free radical curable inkjet inks contain one or more monofunctional polymerizable compounds at 40% to 80% by weight of the total weight of the polymerizable composition.

8. The ink kit of claim 1, wherein one or more colored free radical curable inkjet inks forming the ink kit include a) Cyan free radical curable inkjet inks contain CI pigment blue 60 or copper phthalocyanine pigments; b) Red radical curable inkjet ink containing pigments selected from the following: 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 pigments selected from the following: 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; and d) Black free radical curable inkjet ink containing carbon black pigment.

9. An inkjet printing method for manufacturing decorative laminate materials, comprising the following steps: - To spray images onto a thermoplastic substrate using free radical curable inkjet inks colored with the ink kit according to claim 1; - Solidify the image; - Apply the free radical curable liquid of the ink kit according to any one of claims 1 to 8 onto the image; as well as -The free radical can solidify the liquid.

10. The inkjet printing method according to claim 9, wherein it is performed by: a) In a multi-pass printing process, images are jetted onto a thermoplastic substrate using free radical curable inkjet inks colored with the ink kit described above; b) Spray the free radical curable liquid of the ink kit described above onto the image; as well as c) UV curing of the colored radical-curable inkjet ink and radical-curable liquid using a UV LED with spectral emission in the 360 ​​to 400 nm range.

11. The inkjet printing method according to claim 9, wherein it is performed by: a) In a multi-pass printing process, images are jetted onto a thermoplastic substrate using free radical curable inkjet inks colored with the ink kit described above; b) UV curing of the image using a UV LED with spectral emission in the 360 ​​to 400 nm range; c) Apply the free radical curable liquid of the ink kit as described above onto the image; as well as d) UV curing the free radical curable liquid using a UV LED with spectral emission in the 360 ​​to 400 nm range; wherein the free radical curable liquid is applied by a coating or printing technique other than inkjet printing.

12. The inkjet printing method according to claim 9, wherein it is performed by: a) In a single-pass printing process, an image is jetted onto a thermoplastic substrate using free radical curable inkjet inks colored with the ink kit described above; b) UV curing of the image using a UV LED with spectral emission in the 360 ​​to 400 nm range; c) Apply the free radical curable liquid of the ink kit as described above onto the image; as well as d) UV curing the free radical curable liquid using a UV LED with spectral emission in the 360 ​​to 400 nm range; wherein the free radical curable liquid is applied by a coating or printing technique other than inkjet printing.

13. The inkjet printing method of claim 11, wherein the free radical curable liquid is applied by a coating technique selected from spraying, blade coating, extrusion coating, hopper coating and curtain coating, or by a printing technique selected from flexographic printing, gravure printing and offset printing.

14. The inkjet printing method according to claim 9, wherein the curing of the image and / or the free radical curable liquid is performed by electron beam curing.

15. The inkjet printing method according to any one of claims 9 to 14, wherein the thermoplastic substrate comprises polyvinyl chloride.

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