Light-curing varnish composition

Abstract

To provide a photocurable varnish composition capable of giving a cured product which combines gloss, slipperiness, blocking resistance, leveling property, and hardness (scratch resistance and pencil hardness).SOLUTION: A photocurable varnish composition contains at least a photopolymerizable compound, a photopolymerization initiator, and a lubricant. The lubricant contains: a compound (A) which is an ester of a polyol having three or more hydroxyl groups in the molecule and a C12-20 fatty acid and has one or more hydroxyl groups in the molecule; and / or a compound (B) which is a C12-20 fatty acid. The content of the lubricant is 0.5-4.0 mass% based on the photopolymerizable compound.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a photocurable varnish composition. [Background technology]

[0002] After printing on the surface of various substrates such as films, sheets, and plates, it is common to coat the substrate with an overprint varnish to protect the substrate itself and the printed surface and to impart gloss.

[0003] For example, Patent Document 1 discloses an active energy ray-curable overcoat varnish containing an amino group-containing styrene (meth)acrylic resin (A), a di- to tri-functional (meth)acrylate monomer (B) having a cyclic structure, and a di- to tetra-functional (meth)acrylate monomer (C) other than the monomer (B), wherein the di- to tri-functional (meth)acrylate monomer (B) having a cyclic structure contains a di- to tri-functional (meth)acrylate monomer having a heterocycle and a di- to tri-functional (meth)acrylate monomer having an aromatic ring. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6421401 Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, overprint varnishes have been required to have not only gloss and hardness but also slip properties, anti-blocking properties, and leveling properties, especially when used for carton packaging.

[0006] With regard to the active energy ray-curable overcoat varnish of Patent Document 1, the gloss and hardness of the cured product are discussed, but the slip properties, blocking resistance, and leveling properties have not been sufficiently investigated, leaving room for further improvement.

[0007] The present invention has been made in consideration of the above-mentioned problems and provides a photocurable varnish composition that can give a cured product that combines gloss, slipperiness, blocking resistance, leveling properties, and hardness (scratch resistance and pencil hardness). [Means for solving the problem]

[0008] The present invention provides a photocurable varnish composition that contains at least a photopolymerizable compound, a photopolymerization initiator, and a lubricant, wherein the lubricant is an ester of a polyol having three or more hydroxyl groups in the molecule and a fatty acid having 12 to 20 carbon atoms, and contains a compound (A) having one or more hydroxyl groups in the molecule and / or a compound (B) which is a fatty acid having 12 to 20 carbon atoms, and the content of the lubricant is 0.5 to 4.0 mass % relative to the photopolymerizable compound.

[0009] In the photocurable varnish composition of the present invention, the compound (A) is preferably an ester of a polyol having three or more hydroxyl groups in the molecule and a linear saturated fatty acid having 12 to 20 carbon atoms, and is a compound having one or more hydroxyl groups in the molecule. Furthermore, the compound (A) is preferably an ester of stearic acid and a polyol having three or more hydroxyl groups in the molecule, and is preferably a compound having one or more hydroxyl groups in the molecule. The compound (A) is preferably a diester of stearic acid and a polyol having three or more hydroxyl groups in the molecule. The polyol having three or more hydroxyl groups in the molecule is preferably one or more selected from pentaerythritol, sorbitan, and glycerin. The compound (B) is preferably stearic acid and / or isostearic acid. It is also preferable that the lubricant further contains a bisamide having 34 to 38 carbon atoms and / or a monoamide having 12 to 18 carbon atoms. The photopolymerizable compound preferably contains an epoxy (meth)acrylate oligomer and / or an amino group-containing oligomer. The photocurable varnish composition of the present invention preferably further contains an acrylic resin. The photocurable varnish composition of the present invention preferably further contains an organic solvent. The photocurable varnish composition of the present invention is preferably applied by gravure printing. The photocurable varnish composition of the present invention is preferably cured by an LED. [Effects of the Invention]

[0010] The present invention can provide a photocurable varnish composition that can give a cured product that combines gloss, slipperiness, blocking resistance, leveling properties, and hardness (scratch resistance and pencil hardness). DETAILED DESCRIPTION OF THE INVENTION

[0011] The present invention provides a photocurable varnish composition that contains at least a photopolymerizable compound, a photopolymerization initiator, and a lubricant, wherein the lubricant is an ester of a polyol having three or more hydroxyl groups in the molecule and a fatty acid having 12 to 20 carbon atoms, and contains a compound (A) having one or more hydroxyl groups in the molecule and / or a compound (B) which is a fatty acid having 12 to 20 carbon atoms, and the content of the lubricant is 0.5 to 4.0 mass % relative to the photopolymerizable compound.

[0012] The photocurable varnish composition of the present invention forms a coating film by irradiating light after coating. It is believed that compound (A) or (B) contained in the photocurable varnish composition migrates from within the coating film to the surface of the coating film after it is formed. It is believed that compound (A) or (B) protects the coating film by orienting at the coating film surface, improving its slip properties and blocking resistance. Furthermore, an appropriate amount does not impair the smoothness of the coating film surface, imparting hardness (scratch resistance, pencil hardness) without compromising gloss or leveling properties. However, the present invention should not be construed as being limited to the above mechanism.

[0013] (Photopolymerizable compound) The photocurable varnish composition of the present invention contains a photopolymerizable compound.

[0014] As the photopolymerizable compound, a photopolymerizable oligomer having one or more ethylenically unsaturated bonds of one or more types selected from the group consisting of a (meth)acryloyl group, a vinyl group, and the like can be used.

[0015] The photopolymerizable oligomer may be, for example, one or more selected from the group consisting of polydiallyl phthalate oligomer, neopentyl glycol oligo(meth)acrylate oligomer, 1,4-butanediol oligo(meth)acrylate oligomer, 1,6-hexanediol oligo(meth)acrylate oligomer, trimethylolpropane oligo(meth)acrylate oligomer, pentaerythritol oligo(meth)acrylate oligomer, urethane (meth)acrylate oligomer, epoxy (meth)acrylate oligomer, polyester (meth)acrylate oligomer, rosin-modified epoxy (meth)acrylate oligomer, unsaturated polyester oligomer, polyether (meth)acrylate oligomer, acrylic oligomer having unreacted unsaturated groups, unsaturated polyether oligomer, unsaturated polyamide oligomer, unsaturated polyurethane oligomer, acrylic-modified phenolic oligomer, and amino group-containing oligomer.

[0016] Among these, it is preferable to contain an epoxy (meth)acrylate oligomer and / or an amino group-containing oligomer from the viewpoint of curability and gloss.

[0017] As the epoxy (meth)acrylate oligomer, one or more types selected from the group consisting of the "EBECRYL" series manufactured by Daicel Allnex, the "CN" series manufactured by Arkema, the "Laromer" series manufactured by BASF, and the like can be used.

[0018] As the amino group-containing oligomer, for example, one or more selected from the group consisting of "Agisyn008" (amino group-containing photopolymerizable oligomer) manufactured by DSM and "CN371" (an oligomer of an acrylated amine compound having two photopolymerizable functional groups and two amino groups in the molecule) manufactured by Sartomer can be used.

[0019] From the viewpoint of suitably adjusting the viscosity when diluted, the photopolymerizable compound preferably contains a (meth)acrylate monomer, and more preferably contains a photopolymerizable monomer such as a (meth)acrylate monomer in addition to the photopolymerizable oligomer.

[0020] The photopolymerizable monomer may be a monofunctional or polyfunctional (meth)acrylate.

[0021] Examples of the monofunctional (meth)acrylate include ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, hexadecyl (meth)acrylate, octadecyl (meth)acrylate, isoamyl (meth)acrylate, isodecyl (meth)acrylate, isostearyl (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, methoxyethyl (meth)acrylate, butoxyethyl (meth)acrylate, phenoxyethyl (meth)acrylate, and phenoxydiethylene glycol (meth). tetrahydrofurfuryl (meth)acrylate, nonylphenoxyethyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, glycidyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, 3-chloro-2-hydroxypropyl (meth)acrylate, diethylaminoethyl (meth)acrylate, nonylphenoxyethyl tetrahydrofurfuryl (meth)acrylate, caprolactone-modified tetrahydrofurfuryl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, and the like.

[0022] Examples of the polyfunctional (meth)acrylate include 1,4-butanediol di(meth)acrylate, 3-methyl-1,5-pentanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 2-methyl-1,8-octanediol di(meth)acrylate, 2-butyl-2-ethyl-1,3-propanediol di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, Di(meth)acrylates of dihydric alcohols such as ethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, di(meth)acrylate of tris(2-hydroxyethyl)isocyanurate, and mixtures of 1 mole of neopentyl glycol with 4 moles or more of ethylene oxide or propylene oxide. Di(meth)acrylates of diols obtained by addition of 1 mole of bisphenol A to 2 moles of ethylene oxide or propylene oxide, di(meth)acrylates of diols obtained by addition of 1 mole of bisphenol A to 2 moles of ethylene oxide or propylene oxide, poly(meth)acrylates of trihydric or higher polyhydric alcohols such as trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, and poly(meth)acrylate of dipentaerythritol, Examples of the poly(meth)acrylate include poly(meth)acrylates of polyoxyalkylene polyols such as triol tri(meth)acrylate obtained by adding 3 moles or more of ethylene oxide or propylene oxide to 1 mole of serine, di- or tri(meth)acrylate of triol obtained by adding 3 moles or more of ethylene oxide or propylene oxide to 1 mole of trimethylolpropane, and di(meth)acrylate of diol obtained by adding 4 moles or more of ethylene oxide or propylene oxide to 1 mole of bisphenol A.

[0023] As the photopolymerizable monomer, from the viewpoints of curability and gloss imparting, and of suitably adjusting the viscosity when diluted, a diol di(meth)acrylate obtained by adding 4 moles or more of ethylene oxide or propylene oxide to 1 mole of bisphenol A is preferred, and ethoxylated (4) bisphenol A diacrylate is more preferred.

[0024] The photopolymerizable compounds may be used alone or in combination of two or more.

[0025] The photopolymerizable compound is preferably contained in an amount of 30 to 70% by mass relative to the total amount of the photocurable varnish composition of the present invention.

[0026] In the photopolymerizable compound, the content of the photopolymerizable oligomer is preferably 20 to 60% by mass based on the total amount of the photopolymerizable compound. The content of the photopolymerizable monomer is preferably 40 to 80% by mass based on the total amount of the photopolymerizable compound.

[0027] (Photopolymerization initiator) The photocurable varnish composition of the present invention contains a photopolymerization initiator.

[0028] Examples of the photopolymerization initiator include acylphosphine oxide-based polymerization initiators and α-hydroxyketone-based polymerization initiators.

[0029] Examples of the acylphosphine oxide polymerization initiator include bis-2,6-dimethoxybenzoyl-2,4,4-trimethylpentylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (Omnirad TPO), bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (Omnirad 819 or SB-PI719), and ethoxy(2,4,6-trimethylbenzoyl)phenylphosphine oxide (TPOL).

[0030] Examples of the α-hydroxyketone polymerization initiator include 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]-phenyl}-2-methyl-propan-1-one (Omnirad 127), 2-hydroxy-4'-hydroxyethoxy-2-methylpropiophenone (Omnirad 2959), 1-hydroxycyclohexyl phenyl ketone (Omnirad 184), oligo{2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone} (ESACURE ONE), 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, and 1-hydroxycyclohexyl phenyl ketone.

[0031] The photopolymerization initiator may be benzophenone, 4,4'-diethylaminobenzophenone, ethyl Michler's ketone, diethylthioxanthone, 2-methyl-1-(4-methylthio)phenyl-2-morpholinopropan-1-one, 4'-(methylthio)-α-morpholino-α-methylpropiophenone, 4-benzoyl-4'-methyldiphenyl sulfide, 1-chloro-4-propoxythioxanthone, isopropylthioxanthone, 2,4-diethylthioxanthone, 2,2-dimethyl-2-hydroxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2-benzyl-2-dimethylamino-1-(morpholinophenyl)-butan-1-one, or the like.

[0032] Among these, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (OmniradTPO) is preferred from the viewpoint of inhibiting coloration.

[0033] The photopolymerization initiators may be used alone or in combination of two or more.

[0034] The amount of the photopolymerization initiator is preferably 5 to 20% by mass based on the total amount of the photopolymerizable compound.

[0035] (lubricant) The photocurable varnish composition of the present invention contains a lubricant. The lubricant is an ester of a polyol having three or more hydroxyl groups in the molecule and a fatty acid having 12 to 20 carbon atoms, and contains a compound (A) having one or more hydroxyl groups in the molecule and / or a compound (B) which is a fatty acid having 12 to 20 carbon atoms. The above compounds (A) and (B) are also called ester-based lubricants.

[0036] From the viewpoints of solubility, sliding angle, and blocking resistance, the compound (A) is an ester of a polyol having three or more hydroxyl groups in the molecule and a linear saturated fatty acid having 12 to 20 carbon atoms, preferably a compound having one or more hydroxyl groups in the molecule, more preferably an ester of a polyol having three or more hydroxyl groups in the molecule and stearic acid, more preferably a compound having one or more hydroxyl groups in the molecule, and even more preferably a diester of a polyol having three or more hydroxyl groups in the molecule and stearic acid.

[0037] The polyol having three or more hydroxyl groups in the molecule is preferably one or more selected from pentaerythritol, sorbitan, and glycerin, from the viewpoint of suitably imparting slip properties, blocking resistance, gloss value, and hardness, and more preferably pentaerythritol.

[0038] Examples of the compound (B) include capric acid, lauric acid, myristic acid, pentadecylic acid, palmitic acid, palmitoleic acid, margaric acid, stearic acid, isostearic acid, oleic acid, vaccenic acid, linoleic acid, linolenic acid, eleostearic acid, arachidic acid, mead acid, and arachidonic acid. Among these, stearic acid and / or isostearic acid are preferred from the viewpoint of sliding angle and blocking resistance.

[0039] The ester-based lubricant preferably contains the compound (A), and may be used in combination with the compound (A) and the compound (B), but it is more preferable to use the compound (A) alone.

[0040] From the viewpoint of imparting more suitable lubricating properties, the lubricant preferably further contains a bisamide having 34 to 38 carbon atoms and / or a monoamide having 12 to 18 carbon atoms (also called an amide-based lubricant). As the amide-based lubricant, oleic acid amide and ethylene bisoleic acid are more preferred, and ethylene bisoleic acid is even more preferred.

[0041] The amide-based lubricant is preferably contained in an amount of 10 to 150% by mass relative to the mass of the ester-based lubricant.

[0042] The lubricant preferably contains the compound (A), and may be a combination of the compound (A) and the compound (B), but it is more preferable to use the compound (A) alone.

[0043] The content of the lubricant is 0.5 to 4.0% by mass based on the total amount of the photopolymerizable compound. If the content of the lubricant is less than 0.5% by mass relative to the total amount of the photopolymerizable compound, the lubricity, anti-blocking properties and hardness will decrease, and if it exceeds 4.0% by mass, the gloss will decrease.

[0044] The content of the lubricant is preferably 1.0% by mass or more, more preferably 1.3% by mass or more, and even more preferably 1.5% by mass or more, based on the total amount of the photopolymerizable compound. Furthermore, the content of the lubricant is preferably 4.0% by mass or less, more preferably 3.6% by mass or less, even more preferably 3.0% by mass or less, and particularly preferably 2.5% by mass or less, relative to the total amount of the photopolymerizable compound.

[0045] (acrylic resin) The photocurable varnish composition of the present invention preferably further contains an acrylic resin. By including the acrylic resin, it is possible to impart gloss and improve adhesion to the substrate.

[0046] Examples of the acrylic resin include copolymers composed of (meth)acrylate monomers, and the (meth)acrylate may have, as a copolymer component, an acid group-containing monomer such as (meth)acrylic acid, an acrylic acid dimer, crotonic acid, maleic acid, fumaric acid, or itaconic acid. In addition, the copolymer may contain a hydroxyl group-containing monomer such as hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, or hydroxypentyl (meth)acrylate as a copolymerization component.

[0047] Other monomers constituting the acrylic resin include alkyl (meth)acrylates such as ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, isobornyl (meth)acrylate, and cyclohexyl (meth)acrylate, (meth)alkylamides, N-methylol (meth)alkylamides, N-butoxymethyl (meth)alkylamides, N,N-dimethyl (meth)alkylamides, N,N-dibutyl (meth)alkylamides, N,N-dioctyl (meth)alkylamides, N-monobutyl (meth)alkylamides, and N-monooctyl (meth)alkylamides. Examples of other monomers include acrylamides such as styrene, α-methylstyrene, vinyl ketone, t-butylstyrene, (meth)acrylonitrile, butadiene, and isoprene.

[0048] The acrylic resin may contain an acrylic oligomer. Examples of the acrylic oligomer include urethane (meth)acrylate oligomers, ether group-containing (meth)acrylate oligomers, ester group-containing (meth)acrylate oligomers such as Sartomer CN704, and epoxy-modified (meth)acrylate oligomers.

[0049] The content of the acrylic resin is preferably 5 to 20% by mass relative to the total amount of the photocurable varnish composition of the present invention.

[0050] (organic solvent) The photocurable varnish composition of the present invention preferably further contains an organic solvent.

[0051] The organic solvent may be any solvent that can contain the various components described above. Examples of the solvent include alcohol-based solvents, ketone-based solvents, ester-based solvents, hydrocarbon-based solvents, halogen-based solvents, ether-based solvents, and nitrogen-containing solvents.

[0052] Examples of the alcohol solvent include methanol, ethanol, isopropyl alcohol, normal propyl alcohol, isobutyl alcohol, normal butyl alcohol, tertiary butyl alcohol, and 2-ethylhexanol.

[0053] Examples of the ketone solvent include acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl propyl ketone, diisobutyl ketone, cyclohexanone, methylcyclohexanone, and diacetone alcohol.

[0054] Examples of the ester solvent include methyl acetate, ethyl acetate, butyl acetate, isobutyl acetate, methoxybutyl acetate, amyl acetate, normal propyl acetate, isopropyl acetate, methyl lactate, ethyl lactate, and butyl lactate.

[0055] Examples of the hydrocarbon solvent include benzene, toluene, xylene, normal hexane, isohexane, cyclohexane, methylcyclohexane, ethylcyclohexane, isooctane, normal decane, and normal heptane.

[0056] Examples of the halogen-based solvent include dichloromethane, chloroform, and trichloroethylene.

[0057] Examples of the ether solvents include diethyl ether, tetrahydrofuran, 1,4-dioxane, 1,3-dioxolane, diisopropyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, 3-methoxy-3-methyl-1-butanol, ethylene glycol monotertiary butyl ether, propylene glycol monomethyl ether propionate, 3-methoxybutanol, diethylene glycol dimethyl ether, anisole, and 4-methylanisole. Examples of the nitrogen-containing solvent include acetonitrile, N,N-dimethylformamide, and N,N-dimethylacetamide.

[0058] The content of the organic solvent may be any amount that can dissolve the various components described above, and is, for example, 20 to 90% by mass relative to the total amount of the photocurable varnish composition of the present invention.

[0059] (Other additives) The photocurable varnish composition of the present invention may contain various additives such as surfactants, polymerization inhibitors, surface conditioners, light stabilizers, antioxidants, plasticizers, waxes, non-polymerizable resins, etc., as long as the effects of the present invention are not impaired. Furthermore, the photocurable varnish composition of the present invention may contain known inorganic or organic coloring materials.

[0060] The plasticizer is preferably a dialkyl dicarboxylate, and more preferably dioctyl sebacate.

[0061] As the wax, from the viewpoint of providing suitable slip properties and blocking resistance, low-polarity waxes such as polyolefin wax, PTFE wax, and Fischer-Tropsch wax are preferred, and from the viewpoint of the contact area, it is preferable to use wax with an average particle diameter larger than the expected varnish film thickness.

[0062] The content of the above other additives is not particularly limited, but is, for example, 0.1 to 5% by mass relative to the total amount of the photocurable varnish composition of the present invention.

[0063] (Method of manufacturing a photocurable varnish composition) The method for producing the photocurable varnish composition of the present invention is not particularly limited, and may be, for example, by stirring and mixing the above-mentioned materials. As the stirring and mixing method, a known method can be appropriately selected and used.

[0064] (Photocurable varnish composition) The photocurable varnish composition of the present invention can give a cured product that has gloss, slipperiness, blocking resistance, leveling properties, and hardness (scratch resistance and pencil hardness).

[0065] The slip properties, blocking resistance, leveling properties, gloss, and hardness (scratch resistance, pencil hardness) of the cured product of the photocurable varnish composition of the present invention can be evaluated by the following methods. The photocurable varnish composition of the present invention is diluted with ethyl acetate so that it takes 16 seconds using a Rigaud Zahn Cup No. 3, and then coated onto CRC (Osaka Paper Co., Ltd.) using a 0.10 mm marrow bar. After that, a UV-LED is irradiated from a position 0.2 cm away from the coated surface so that the UV cumulative light dose per second is 100 to 170 mJ / cm2, yielding a cured product (also called a coating film) with a thickness of 2 to 10 μm.

[0066] The slipperiness of the cured product is determined by measuring the sliding angle of the cured product using a sliding angle tester manufactured by Toyo Seiki Seisaku-sha, and if the sliding angle is less than 20 degrees, it can be determined that the cured product has sufficient slipperiness. The sliding angle is preferably less than 15 degrees, and more preferably less than 12 degrees.

[0067] The blocking resistance of the cured product was measured by combining the front and back surfaces of the cured product and measuring 1000 g / cm 2 After applying a load of 1000kJ / s and leaving it at 40°C for 24 hours, there was resistance when peeling off the contact surface, but if the coating film did not peel off from the contact surface, it can be determined that the coating has sufficient blocking resistance. The blocking resistance is preferably such that there is no resistance at all when the contact surface is peeled off, and the coating film does not peel off from the contact surface.

[0068] The leveling ability of the cured product can be determined to be sufficient if the surface of the cured product is visually observed and only a small amount of unevenness occurs across the entire coating film. The leveling property is preferably such that no unevenness occurs across the entire coating film.

[0069] Regarding the gloss of the cured product, the surface of the cured product is measured for 60° specular gloss according to JIS K 5600-4-7:1999, and if it is 70% or higher, it can be determined that the gloss is sufficient. The specular gloss value is preferably 75% or more, and more preferably 80% or more.

[0070] The hardness (scratch resistance) of the cured product is determined by the hardness of the coating film when the surface is rubbed with the back of a fingernail 2 to 10 times. If only a portion of the film peels off, it can be determined that the film has sufficient scratch resistance. The scratch resistance is preferably such that the coating film is not scratched at all when the surface is rubbed five times with the back of a fingernail.

[0071] The hardness (pencil hardness) of the cured product is determined to be sufficient if the surface of the cured product is tested using a pencil of hardness H to 3H according to JIS K 5600-5-4:1999, and the coating film is indented and partially peels off. The pencil hardness is preferably such that, in a test using a pencil with a hardness of 2H, no depressions are formed in the coating film, or depressions are formed but the coating film does not fall off.

[0072] Examples of methods for applying the photocurable varnish composition of the present invention include known printing methods such as offset printing, gravure printing, flexographic printing, letterpress printing, roller coating, and spray coating. Among these, gravure printing is preferred from the viewpoint of the composition of the photocurable varnish composition and the viscosity during printing.

[0073] From the viewpoint of suitable application, the photocurable varnish composition of the present invention preferably has a viscosity of 20 seconds or less, more preferably 16 seconds or less, as measured with a Rigaud Zahn Cup No. 3.

[0074] The photocurable varnish composition of the present invention can be applied to any known material including paper substrates, surfaces of resin molded bodies such as various resin sheets, metal surfaces, ceramic surfaces, and wood surfaces, but is particularly suitable for use on carton packaging.

[0075] After being applied by the above-described application method, the photocurable varnish composition of the present invention is cured to form a cured product. In the curing method, the active energy rays may be ultraviolet rays, electron beams, α rays, β rays, γ rays, X-rays, or the like, as long as they can provide the energy necessary to promote the polymerization reaction of the polymerizable components in the composition. In particular, from the viewpoint of power consumption and maintenance costs, curing by LED is preferable. As the LED, an ultraviolet light emitting diode (UV-LED), an ultraviolet laser diode (UV-LD), or the like can be used.

[0076] The thickness of the cured product of the photocurable varnish composition of the present invention may be determined appropriately depending on the application, but is, for example, 2 to 10 μm. [Example]

[0077] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, "%" means "% by mass" and "parts" means "parts by mass."

[0078] The materials used in the examples and comparative examples are as follows.

[0079] (organic solvent) Ethyl acetate Isopropyl alcohol (IPA) Methylcyclohexane (Photopolymerizable compound) LAROMER8986 (product name "LAROMER LR8986", epoxy acrylate oligomer, manufactured by BASF) AGISYN008 (trade name "Agisyn008", amino group-containing photopolymerizable oligomer, manufactured by DSM) GM62R4E (product name "Qualicure GM62R4E", ethoxylated (4) bisphenol A diacrylate, manufactured by Qualipoly Chemical Co.) DPHA (Dipentaerythritol hexaacrylate) (acrylic resin) BR-116 (product name "Dianal BR-116" acrylic resin, manufactured by Mitsubishi Chemical Corporation) (Photopolymerization initiator) TPO (2,4,6-trimethylbenzoyl-diphenylphosphine oxide) (wax) SasolWax spray 30 (manufactured by Sasol) (ester-based lubricant) Pentaerythritol Distearate Glycerin mono-distearate (product name "Rikemal S-200", manufactured by Riken Vitamin Co., Ltd.) stearic acid Isostearic acid Stearyl stearate Pentaerythritol Tetrastearate Sorbitan tristearate (product name "Leodor SP-S30V", manufactured by Kao Chemical Co., Ltd.) Glycerin monostearate (product name "Excel S-95 Powder", manufactured by Kao Corporation) (amide-based lubricant) Oleic acid amide (trade name "Fatty Acid Amide ON", manufactured by Kao Corporation) Ethylene bis oleamide (trade name "ITOHWAX J-500", manufactured by Ito Oil Mills) (plasticizer) DOS (Dioctyl Sebacate)

[0080] (Preparation of photocurable varnish composition) The materials were mixed in the formulations shown in Table 1 using a normal ink manufacturing device to prepare photocurable varnish compositions according to the examples and comparative examples.

[0081] (Preparation of cured product) The photocurable varnish compositions according to the examples and comparative examples were diluted with ethyl acetate so that the time required for application was 16 seconds using a Rigaud Zahn Cup No. 3, and the varnish was applied to CRC (manufactured by Osaka Paper Co., Ltd.) using a 0.10 mm marrow bar. After that, the varnish was applied from a position 0.2 cm away from the coated surface with a UV integrated light dose of 100 to 170 mJ / cm per second. 2 The resin was irradiated with UV-LED so as to form a cured product (also called a coating film) with a thickness of 5 μm. The resulting cured products were evaluated for slipperiness, blocking resistance, leveling ability, gloss, and hardness (scratch resistance, pencil hardness), and those that were all rated as "good" or "good" were deemed to have passed.

[0082] (Slipperiness) The sliding angle of each cured product was measured using a sliding angle tester manufactured by Toyo Seiki Seisakusho, and evaluated according to the following criteria. ◎: Sliding angle is less than 12 degrees. Good: Sliding angle is 12 degrees or more but less than 15 degrees. △: Sliding angle is between 15 degrees and 20 degrees. ×: The sliding angle exceeded 20 degrees.

[0083] (blocking resistance) The surface and back of each cured product were combined to a weight of 1000 g / cm 2 After leaving the sample at 40°C for 24 hours under a load of 100g, the sample was evaluated according to the following criteria. ◯: There was absolutely no resistance when peeling off the contact surface, and the coating film did not peel off from the contact surface. △: There was resistance when peeling off the contact surface, but the coating film did not peel off from the contact surface. ×: There was resistance when peeling off the contact surface, and the coating film peeled off from the contact surface.

[0084] (Leveling ability) The surface of each cured product was visually observed and evaluated according to the following criteria. ◯: There was no unevenness throughout the coating film. △: A small amount of unevenness occurred on the entire coating film. ×: Significant unevenness was observed throughout the coating film.

[0085] (glossy) The surface of each cured product was measured for 60° specular gloss in accordance with JIS K 5600-4-7:1999 and evaluated according to the following criteria. 〇: 60° mirror gloss is 80% or more. △: 60° specular gloss is 70% to 79%. ×: 60° specular gloss is less than 70%.

[0086] (scratch resistance) The surface of each cured product was rubbed five times with the back of a fingernail and evaluated according to the following criteria. ◯: No scratches on the coating. △: Part of the coating film peeled off. ×: Most of the coating film peeled off or completely peeled off.

[0087] (Pencil hardness) The surface of each cured product was tested using a pencil with a hardness of 2H according to JIS K 5600-5-4:1999, and evaluated according to the following criteria. ◯: No depressions were observed in the coating film, or depressions were observed but no peeling of the coating film was observed. △: Depressions occurred in the coating film and some of the coating film fell off. ×: Most of the coating film peeled off or completely peeled off.

[0088] [Table 1]

[0089] From the examples, it was confirmed that by using a photocurable varnish composition containing at least a photopolymerizable compound, a photopolymerization initiator, and a lubricant, wherein the lubricant is an ester of a polyol having three or more hydroxyl groups in the molecule and a fatty acid having 12 to 20 carbon atoms, and containing compound (A) having one or more hydroxyl groups in the molecule, and / or compound (B) which is a fatty acid having 12 to 20 carbon atoms, and the content of the lubricant is 0.5 to 4.0 mass% relative to the photopolymerizable compound, it is possible to obtain a cured product that combines gloss, slip properties, blocking resistance, leveling properties, and hardness (scratch resistance and pencil hardness). Furthermore, from Examples 9 and 10, which further contained a bisamide having 34 to 38 carbon atoms and / or a monoamide having 12 to 18 carbon atoms (amide-based lubricant) as a lubricant, it was confirmed that by further containing an amide-based lubricant, slip properties can be further improved. On the other hand, in Comparative Example 1, which did not contain the above-mentioned compound (A) or compound (B) as a lubricant, the pencil hardness of the cured product was insufficient, and in Comparative Examples 2 and 3, the slipperiness of the cured product was insufficient. Furthermore, in Comparative Example 4, which did not contain a lubricant, the slipperiness and hardness of the cured product were insufficient. Furthermore, in Comparative Example 5, in which the content of lubricant was too high, the gloss of the cured product was insufficient, and in Comparative Example 6, in which the content of lubricant was too low, the slipperiness of the cured product was insufficient. [Industrial Applicability]

[0090] It is possible to provide a photocurable varnish composition that can give a cured product that combines gloss, slipperiness, blocking resistance, leveling properties, and hardness (scratch resistance and pencil hardness).

Claims

1. Contains at least a photopolymerizable compound, a photopolymerization initiator, and a lubricant, The lubricant is a compound (A) which is an ester of a polyol having three or more hydroxyl groups in the molecule and a fatty acid having 12 to 20 carbon atoms and has one or more hydroxyl groups in the molecule, and / or In addition to the compound (B) which is a fatty acid having 12 to 20 carbon atoms, Contains a bisamide having 34 to 38 carbon atoms and / or a monoamide having 12 to 18 carbon atoms, The content of the lubricant is 0.5 to 4.0% by mass based on the photopolymerizable compound. Photocurable varnish composition.

2. The photocurable varnish composition according to claim 1, wherein the compound (A) is an ester of a polyol having three or more hydroxyl groups in the molecule and a linear saturated fatty acid having 12 to 20 carbon atoms, and the compound has one or more hydroxyl groups in the molecule.

3. 3. A photocurable varnish composition according to claim 2, wherein the compound (A) is an ester of a polyol having three or more hydroxyl groups in the molecule and stearic acid, and is a compound having one or more hydroxyl groups in the molecule.

4. 4. A photocurable varnish composition according to claim 3, wherein the compound (A) is a diester of stearic acid and a polyol having three or more hydroxyl groups in the molecule.

5. 5. A photocurable varnish composition according to claim 1, wherein the polyol having three or more hydroxyl groups in the molecule is one or more selected from pentaerythritol, sorbitan, and glycerin.

6. 6. A photocurable varnish composition according to claim 1, wherein the compound (B) is stearic acid and / or isostearic acid.

7. 7. The photocurable varnish composition according to claim 1, wherein the photopolymerizable compound contains an epoxy (meth)acrylate oligomer and / or an amino group-containing oligomer.

8. The photocurable varnish composition according to any one of claims 1 to 7, further comprising an acrylic resin.

9. The photocurable varnish composition according to any one of claims 1 to 8, further comprising an organic solvent.

10. The photocurable varnish composition according to any one of claims 1 to 9, which is applied by gravure printing.

11. The photocurable varnish composition according to any one of claims 1 to 10, which is cured by LED.

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