Active energy ray-curable coating composition

Abstract

Provided is an active energy ray-curable coating composition which, when applied to a printed matter (especially a printed matter printed by an electrophotographic method), has a small load on the environment, exhibits excellent adhesion, and can impart excellent glossiness. This active energy ray-curable coating composition contains a resin, an ethylenically unsaturated compound, an initiator, and a polymerization inhibitor. The resin includes an amine-modified styrene (meth)acrylic resin. The contained amount of the amine-modified styrene (meth)acrylic resin is 5-30 mass%. The ethylenically unsaturated compound includes at least one of acryloyl morpholine or vinylcaprolactam. The total of the contained amount of at least one of acryloyl morpholine or vinylcaprolactam is 41 mass% or more. The polymerization inhibitor contains a piperidine derivative. The piperidine derivative is contained in an amount of 0.05-1 mass% and has a viscosity of 40-380 mPa·s at 25°C.

Description

Active energy ray-curable coating composition

[0001] The present invention relates to an active energy ray-curable coating composition. More specifically, the present invention relates to an active energy ray-curable coating composition that imparts a small environmental load, excellent adhesion, and excellent gloss when applied to printed matter (particularly electrophotographically printed matter).

[0002] Conventionally, electrophotographically printed materials are laminated to protect the printed surface and to impart decorative properties. In response to this, active energy ray-curable overprint varnishes have been developed to reduce costs and further impart decorative properties (Patent Document 1).

[0003] Patent No. 3246671

[0004] However, the varnish described in Patent Document 1 has the problem that when applied to printed matter (particularly printed matter printed by an electrophotographic method), it does not have sufficient adhesion and is unable to impart sufficient gloss.

[0005] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an active energy ray-curable coating composition that imparts little environmental load, exhibits excellent adhesion, and can impart excellent gloss when applied to printed matter (particularly printed matter printed by an electrophotographic method).

[0006]

[0013] One aspect of the present invention that solves the above-mentioned problems is an active energy ray-curable coating composition comprising: a resin; an ethylenically unsaturated compound; an initiator; and a polymerization inhibitor; wherein the resin comprises an amine-modified styrene (meth)acrylic resin, and the content of the amine-modified styrene (meth)acrylic resin is 5 to 30 mass %; the ethylenically unsaturated compound comprises at least one of acryloylmorpholine and vinylcaprolactam, and the total content of at least one of the acryloylmorpholine and the vinylcaprolactam is 41 mass % or more; the polymerization inhibitor comprises a piperidine derivative, and the content of the piperidine derivative is 0.05 to 1 mass %; and the active energy ray-curable coating composition has a viscosity at 25°C of 40 to 380 mPa s.

[0007] Furthermore, one aspect of the present invention that solves the above-mentioned problem is a coated printed material in which the above-mentioned active energy ray-curable coating composition is applied to a printed material that has been printed by an electrophotographic method.

[0008] <Active Energy Ray-Curable Coating Composition> An active energy ray-curable coating composition (hereinafter also referred to as coating composition) according to one embodiment of the present invention contains a resin, an ethylenically unsaturated compound, an initiator, and a polymerization inhibitor. The resin contains an amine-modified styrene (meth)acrylic resin. The content of the amine-modified styrene (meth)acrylic resin is 5 to 30% by mass. The ethylenically unsaturated compound contains at least one of acryloylmorpholine and vinylcaprolactam. The total content of at least one of acryloylmorpholine and vinylcaprolactam is 41% by mass or more. The polymerization inhibitor contains a piperidine derivative. The content of the piperidine derivative is 0.05 to 1% by mass. The viscosity at 25°C is 40 to 380 mPa·s. Each of these components will be described below.

[0009] (Resin) The resin includes an amine-modified styrene (meth)acrylic resin. Any amine-modified styrene (meth)acrylic resin obtained by known techniques can be used as long as it is a styrene (meth)acrylic resin having an amino group. Specifically, the amine-modified styrene (meth)acrylic resin includes an α,β-unsaturated double bond group-containing compound having an amino group, a copolymer of a styrene-based compound and an α,β-unsaturated double bond group-containing compound (excluding styrene-based compounds), and a product obtained by reacting a styrene-acrylic copolymer having a carboxylic acid group with ethyleneimine (aminoethylation). Among these, the amine-modified styrene (meth)acrylic resin is preferably a copolymer of an α,β-unsaturated double bond group-containing compound having an amino group, a styrene-based compound and an α,β-unsaturated double bond group-containing compound (excluding styrene-based compounds).

[0010] Examples of the α,β-unsaturated double bond group-containing compound having an amino group include acrylic acid esters such as N,N-dimethylaminoethyl (meth)acrylate, N,N-diethylaminoethyl (meth)acrylate, and N,N-dimethylaminopropyl (meth)acrylate, and acrylamides such as N,N-dimethylaminoethyl (meth)acrylamide, N,N-dimethylaminoethyl (meth)acrylamide, and N,N-dimethylaminopropyl (meth)acrylamide.

[0011] The styrene-based compounds include styrene, α-methylstyrene, and vinylstyrene.

[0012] The α,β-unsaturated double bond group-containing compound is not particularly limited as long as it is other than the above-mentioned acrylic acid esters having an amino group and styrene-based monomers. Examples of the α,β-unsaturated double bond group-containing compound include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and cyclohexyl (meth)acrylate.

[0013] The weight-average molecular weight of the amine-modified styrene (meth)acrylic resin is preferably 3,000 or more, more preferably 5,000 or more. The weight-average molecular weight of the amine-modified styrene (meth)acrylic resin is preferably 30,000 or less, more preferably 20,000 or less. When the weight-average molecular weight is within the above range, the coating composition is prevented from penetrating into paper, and good coating properties are obtained due to the appropriate viscosity. Furthermore, the coating composition can improve adhesion. In this embodiment, the weight-average molecular weight is a polystyrene-equivalent weight-average molecular weight measured by gel permeation chromatography (hereinafter, GPC). Specifically, GPC measurements can be performed using an HLC-8020 (manufactured by Tosoh Corporation) as an apparatus, a TSKgel Super HM-M (manufactured by Tosoh Corporation) as a column, and tetrahydrofuran as an eluent, and the molecular weight can be calculated by comparison with the molecular weight of standard polystyrene.

[0014] The amine value of the amine-modified styrene (meth)acrylic resin is preferably 10 mgKOH / g or more, more preferably 30 mgKOH / g or more. The amine value is preferably 130 mgKOH / g or less, more preferably 100 mgKOH / g or less. In this embodiment, the amine value is the total amine value (mgKOH) measured in accordance with the method of ASTM D2074.

[0015] The glass transition point (Tg) of the amine-modified styrene (meth)acrylic resin is preferably 10°C or higher, and more preferably 20°C or higher. Furthermore, Tg is preferably 100°C or lower, and more preferably 80°C or lower. Having a Tg within the above range improves the curability of the coating composition, enhances flexibility after curing, and improves adhesion. In this embodiment, Tg may be calculated from the Tg of a homopolymer of the monomers constituting the resin, or may be measured experimentally. A method for calculating Tg from the Tg of a homopolymer of the monomers is, for example, a method of calculation using the FOX formula. An experimental method for measuring Tg is a method of measuring a DSC curve using a differential scanning calorimeter.

[0016] The content of the amine-modified styrene (meth)acrylic resin may be 5% by mass or more, and preferably 15% by mass or more. The content of the amine-modified styrene (meth)acrylic resin may be 30% by mass or less, and preferably 25% by mass or less. If the content of the amine-modified styrene (meth)acrylic resin is less than 5% by mass, the coating composition will suffer from coating defects such as seepage into paper and repelling (a phenomenon in which circular unevenness occurs), resulting in reduced adhesion. On the other hand, if the content of the amine-modified styrene (meth)acrylic resin exceeds 30% by mass, the coating composition will suffer from poor leveling and reduced adhesion. By having the content of the amine-modified styrene (meth)acrylic resin within the above range, the coating composition will exhibit better adhesion and can impart better gloss when applied to printed materials (particularly printed materials printed by an electrophotographic method).

[0017] Returning to the description of the resin as a whole, the resin of this embodiment may contain other resins in addition to the above-described amine-modified styrene (meth)acrylic resin. The other resins are not particularly limited. Examples of the other resins include acrylic resins, polyester resins, allyl resins, petroleum resins, and epoxy resins.

[0018] When other resins are contained, the content of the other resins is not particularly limited, and is, for example, 5 to 15% by mass.

[0019] (Ethylenically Unsaturated Compound) The ethylenically unsaturated compound includes at least one of acryloylmorpholine and vinylcaprolactam.

[0020] The total content of at least one of acryloylmorpholine and vinylcaprolactam is 41% by mass or more, preferably 50% by mass or more. If the total content of at least one of acryloylmorpholine and vinylcaprolactam is less than 41% by mass, the adhesion of the coating composition will decrease.

[0021] Returning to the explanation of the ethylenically unsaturated compound as a whole, the resin of this embodiment may contain an ethylenically unsaturated compound other than the above-mentioned acryloylmorpholine and vinylcaprolactam. The other ethylenically unsaturated compound is not particularly limited. Examples of other ethylenically unsaturated compounds include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, amyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, nonyl (meth)acrylate, dodecyl (meth)acrylate, hexadecyl (meth)acrylate, octadecyl (meth)acrylate, cyclohexyl (meth)acrylate, methoxyethyl (meth)acrylate, butoxyethyl (meth)acrylate, phenoxyethyl (meth)acrylate, nonylphenoxyethyl (meth)acrylate, glycidyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclo Monofunctional (meth)acrylates such as pentenyloxyethyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, benzyl (meth)acrylate, phenylbenzyl (meth)acrylate, and mono(2-acryloyloxyethyl) succinate; N-[2-(acryloyloxy)ethyl]phthalimide; N-[2-(acryloyloxy)ethyl]phthalimide; phthalimides such as [(hydroxy)ethyl]tetrahydrophthalimide, 1,3-butylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,5-pentanediol di(meth)acrylate, 3-methyl-1,5-pentanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,8-octanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, ethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, neopentyl glycol hydroxypivalic acid ester di(meth)acrylate, tris(2-hydroxyethyl)isocyanurate, and two water-soluble polymers. Di(meth)acrylates in which the acid groups are substituted with (meth)acryloyloxy groups, di(meth)acrylates in which two hydroxyl groups of a diol obtained by adding 4 or more moles of ethylene oxide or propylene oxide to 1 mole of neopentyl glycol are substituted with (meth)acryloyloxy groups, di(meth)acrylates in which two hydroxyl groups of a diol obtained by adding 2 moles of ethylene oxide or propylene oxide to 1 mole of bisphenol A are substituted with (meth)acryloyloxy groups, di(meth)acrylates in which two hydroxyl groups of a diol obtained by adding 3 moles of ethylene oxide or propylene oxide to 1 mole of trimethylolpropane are substituted with (meth)acryloyloxy groups, di(meth)acrylates in which two hydroxyl groups of a diol obtained by adding 3 ... bisphenol A Bifunctional (meth)acrylates such as di(meth)acrylates in which two hydroxyl groups of a triol obtained by adding 1 mole or more of ethylene oxide or propylene oxide are substituted with (meth)acryloyloxy groups, and di(meth)acrylates in which two hydroxyl groups of a diol obtained by adding 4 moles or more of ethylene oxide or propylene oxide to 1 mole of bisphenol A are substituted with (meth)acryloyloxy groups, trimethylolpropane tri(meth)acrylate, glycerin triacrylate, pentaerythritol tri(meth)acrylate, trifunctional (meth)acrylates such as tri(meth)acrylate, in which three hydroxyl groups of a triol obtained by adding three or more moles of ethylene oxide or propylene oxide to one mole of trimethylolpropane are substituted with (meth)acryloyloxy groups, and polyfunctional (meth)acrylates having tetrafunctionality or more such as ditrimethylolpropane tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, and dipentaerythritol hexa(meth)acrylate.

[0022] When other ethylenically unsaturated compounds are contained, the content of the other ethylenically unsaturated compounds is not particularly limited. For example, the content of the other ethylenically unsaturated compounds is 5 to 50 mass %.

[0023] (Initiator) The initiator is a component that generates radicals when irradiated with active energy rays, and is blended in order to cure the coating composition.

[0024] The initiator is not particularly limited. Examples of the initiator include benzophenone, diethylthioxanthone, 2-methyl-1-(4-methylthio)phenyl-2-morpholinopropan-1-one, 4-benzoyl-4′-methyldiphenyl sulfide, 1-chloro-4-propoxythioxanthone, isopropylthioxanthone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, and bis-2,6-dimethoxybenzoyl. 2,4,4-trimethylpentylphosphine oxide, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2,2-dimethyl-2-hydroxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,4,6-trimethylbenzyl-diphenylphosphine oxide, 2-benzyl-2-dimethylamino-1-(morpholinophenyl)-butan-1-one, and the like.

[0025] The content of the initiator is not particularly limited. For example, the content of the initiator in the coating composition is preferably 1% by mass or more, more preferably 2% by mass or more. Furthermore, the content of the initiator in the coating composition is preferably 20% by mass or less, more preferably 15% by mass or less. When the content of the initiator is within the above range, the coating composition is easily cured sufficiently.

[0026] (Polymerization inhibitor) The polymerization inhibitor includes a piperidine derivative. The piperidine derivative is not particularly limited. Examples of the piperidine derivative include a linear or cyclic condensation product of N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine and 4-tert-octylamino-2,6-dichloro-1,3,5-triazine, a linear or cyclic condensation product of N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-hexamethylenediamine and 4-morpholino-2,6-dichloro-1,3,5-triazine, a linear or cyclic condensation product of 2-chloro-4,6-di(4-n-butylamino-2,2,6,6-tetramethylpiperidyl)-1,3,5-triazine and 1,2-bis( condensation product of 2-chloro-4,6-di(4-n-butylamino-1,2,2,6,6-pentamethylpiperidyl)-1,3,5-triazine and 1,2-bis(3-aminopropylamino)ethane, condensation product of N,N'-bis-(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine and 4-chlorohexylamino-2,6-dichloro-1,3,5-triazine, 2,2,6,6-tetramethylpiperidine 1-oxyl, 4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxyl, and the like.

[0027] The content of the piperidine derivative may be 0.05% by mass or more, preferably 0.1% by mass or more, and more preferably 0.2% by mass or more. The content of the piperidine derivative may be 1% by mass or less, preferably 0.8% by mass or less, and more preferably 0.5% by mass or less. If the content of the piperidine derivative is less than 0.05% by mass, the coating composition will gel under fluorescent light and its viscosity will increase over time. On the other hand, if the content of the piperidine derivative is more than 1% by mass, the curability of the coating composition will decrease.

[0028] Returning to the explanation of the polymerization inhibitor as a whole, the polymerization inhibitor of this embodiment may contain other polymerization inhibitors in addition to the piperidine derivatives described above. The other polymerization inhibitors are not particularly limited. Examples of the other polymerization inhibitors include nitroso compounds, phenolic compounds, and quinone compounds.

[0029] When other polymerization inhibitors are contained, the content of the other polymerization inhibitors is not particularly limited. For example, the content of the other polymerization inhibitors is 0.05 to 1 mass %.

[0030] (Optional Components) In addition to the components described above, the coating composition of the present embodiment may contain optional components as appropriate. The optional components are not particularly limited. Examples of optional components include leveling agents, antibacterial agents, antistatic agents, surfactants, antifoaming agents, antioxidants, waxes, slip agents, etc.

[0031] Returning to the description of the coating composition as a whole, the active energy ray is not particularly limited. Examples of the active energy ray include ultraviolet rays, electron beams, X-rays, ionizing radiation such as α-rays, β-rays, and γ-rays, microwaves, high-frequency waves, and the like, and may also be visible light, infrared rays, laser beams, and the like.

[0032] Devices that emit ultraviolet rays include LEDs, ultra-high pressure mercury lamps, high pressure mercury lamps, medium pressure mercury lamps, low pressure mercury lamps, metal halide lamps, xenon lamps, carbon arc lamps, helium-cadmium lasers, YAG lasers, excimer lasers, and argon lasers.

[0033] The viscosity of the coating composition of this embodiment at 25°C may be 40 mPa·s or more, and preferably 60 mPa·s or more. The viscosity may be 380 mPa·s or less, and preferably 299 mPa·s or less. When the viscosity is within the above range, the coating composition has excellent leveling properties and is easy to apply. In this embodiment, the viscosity is measured at 25°C using a rheometer (Discovery HR-2, manufactured by TA Instruments) at a shear rate of 100 s -1 The viscosity can be measured by reading the viscosity.

[0034] The object to which the coating composition of the present embodiment is applied is not particularly limited. Examples of the object include electrophotographically printed materials, inkjet printed materials, offset printed materials, flexographically printed materials, plastics, paper, carton, and the like. Among these, the coating composition of the present embodiment is preferably applied to electrophotographically printed materials. That is, electrophotographically printed materials differ from offset printed materials in that they contain more wax and silicone components. Therefore, electrophotographically printed materials tend to have poorer adhesion to coating compositions than offset printed materials, making it difficult to impart gloss. However, the coating composition of the present embodiment has a low environmental impact, exhibits excellent adhesion, and can impart excellent gloss. In the present embodiment, the term "electrophotographically printed materials" encompasses all printed materials printed by a method in which toner is electrostatically attached to a drum and then transferred to an output material.

[0035] The substrate of the printed matter is not particularly limited, and examples thereof include coated paper such as art paper, coated paper, and cast paper, uncoated paper such as fine paper and medium-quality paper, synthetic paper such as Yupo paper, and plastic films such as PET (polyethylene terephthalate), PP (polypropylene), and OPP (biaxially oriented polypropylene).

[0036] The coating composition can be cured in a short time by irradiating it with active energy rays after application to form a film, which tends to reduce production costs. Furthermore, the coating composition does not contain organic solvents and does not release VOCs into the atmosphere, so it has a low environmental impact.

[0037] The method for preparing the coating composition of the present embodiment is not particularly limited. As an example, the coating composition can be prepared by appropriately mixing the above-mentioned components and stirring them using a stirrer.

[0038] The method for applying the coating composition of the present embodiment to a printed material (particularly a printed material printed by an electrophotographic method) is not particularly limited. For example, the coating composition can be applied to the printed material by a known method such as bar coating, gravure coating, flexo coating, roll coating, reverse roll coating, or comma coating.

[0039] The applied coating composition can be cured by irradiation with active energy rays. The irradiation conditions for the active energy rays are not particularly limited. The irradiation conditions may be any conditions that allow the applied coating composition to be sufficiently cured.

[0040] The thickness of the resulting cured film is not particularly limited. For example, the thickness is preferably 4 μm or more, more preferably 6 μm or more. The thickness is preferably 10 μm or less, more preferably 8 μm or less.

[0041] As described above, according to this embodiment, when the coating composition is applied to a printed material (especially an electrophotographically printed material), it has a small environmental impact, exhibits excellent adhesion, and can impart excellent gloss. As a result, the resulting coating composition exhibits excellent adhesion and excellent gloss.

[0042] An embodiment of the present invention has been described above. The present invention is not particularly limited to the above embodiment. Note that the above embodiment mainly describes an invention having the following configuration.

[0043] (1) An active energy ray-curable coating composition comprising a resin, an ethylenically unsaturated compound, an initiator, and a polymerization inhibitor, wherein the resin comprises an amine-modified styrene (meth)acrylic resin, the content of the amine-modified styrene (meth)acrylic resin being 5 to 30 mass %, the ethylenically unsaturated compound comprises at least one of acryloylmorpholine and vinylcaprolactam, the total content of at least one of the acryloylmorpholine and vinylcaprolactam being 41 mass % or more, the polymerization inhibitor comprises a piperidine derivative, the content of the piperidine derivative being 0.05 to 1 mass %, and the viscosity at 25°C being 40 to 380 mPa s.

[0044] According to this configuration, when the active energy ray-curable coating composition is applied to a printed material (particularly a printed material printed by an electrophotographic method), it has a small load on the environment, exhibits excellent adhesion, and can impart excellent gloss.

[0045] (2) The active energy ray-curable coating composition according to (1), wherein the content of the amine-modified styrene (meth)acrylic resin is 15 to 25% by mass.

[0046] According to this configuration, the active energy ray-curable coating composition can exhibit better adhesion and impart better gloss when applied to printed matter (particularly printed matter printed by an electrophotographic method).

[0047] (3) The active energy ray-curable coating composition according to (1) or (2), which has a viscosity at 25°C of 40 to 299 mPa·s.

[0048] According to this configuration, the active energy ray-curable coating composition has excellent leveling properties and is easy to apply.

[0049] (4) The active energy ray-curable coating composition according to any one of (1) to (3), which is applied to a printed matter printed by an electrophotographic method.

[0050] According to this configuration, when the active energy ray-curable coating composition is applied to an electrophotographically printed material, it has a small environmental impact, exhibits excellent adhesion, and can impart excellent gloss.

[0051] (5) A coated printed material, in which the active energy ray-curable coating composition according to any one of (1) to (4) is applied to a printed material printed by an electrophotographic method.

[0052] According to this configuration, the coated printed material exhibits excellent adhesion and gloss.

[0053] The present invention will be described in more detail below with reference to examples and comparative examples. The present invention is not limited to these examples. The values ​​in the tables are based on mass %.

[0054] The raw materials used are as follows. <Resin> Amine-modified styrene (meth)acrylic resins 1 and 2, an amine-modified (meth)acrylic resin, and a styrene (meth)acrylic resin were used, each having the components and properties shown in Table 1 below. The abbreviations in Table 1 are as follows: DM N,N-dimethylaminoethyl methacrylate St Styrene BA Butyl acrylate 2-HEA 2-ethylhexyl acrylate BMA Butyl methacrylate CHMA Cyclohexyl methacrylate MMA Methyl methacrylate

[0055] (Synthesis Example 1 of Amine-Modified Styrene (Meth)acrylic Resin 1) A reaction vessel equipped with a nitrogen gas inlet tube, a thermometer, a condenser, and a stirrer was charged with 90.1 parts of methyl ethyl ketone (MEK) and the atmosphere was replaced with nitrogen gas. The reaction vessel was heated to 110°C, and a mixture of 33.0 parts of N,N-dimethylaminoethyl methacrylate, 57.0 parts of styrene, 10.0 parts of butyl acrylate, and 9.0% of 2,2'-azobis(2-methylpropionate)dimethyl (V-601, manufactured by Wako Pure Chemical Industries, Ltd.) as a polymerization initiator was added dropwise over 2 hours to carry out a polymerization reaction. After completion of the dropwise addition, the mixture was further reacted at 110°C for 3 hours, and then 0.9 parts of V-601 was added and the mixture was reacted at 110°C for 1 hour. Thereafter, the MEK was removed under reduced pressure to obtain an amine-modified styrene-acrylic polymer 1 (weight average molecular weight 9,800, amine value 118 mgKOH / g).

[0056] Amine-modified styrene (meth)acrylic resin 2, amine-modified (meth)acrylic resin, and styrene (meth)acrylic resin were also obtained in the same manner as in Synthesis Example 1, except that the raw materials and amounts thereof were changed to those shown in Table 1.

[0057]

[0058] <Resins> Vylon 220: polyester resin (manufactured by Toyobo Co., Ltd., amorphous polyester resin, molecular weight 3,000, hydroxyl value 50 mg KOH / g, Tg 53°C) Neopolymer S: petroleum resin (manufactured by ENEOS Corporation, aromatic (C9) hydrocarbon resin, molecular weight 1,100, softening point 92°C) UN-7770: urethane oligomer (manufactured by Negami Chemical Industrial Co., Ltd., urethane oligomer having an ester structure, molecular weight 20,000, Tg -41°C) <Ethylenically unsaturated compounds> ACMO: acryloylmorpholine (manufactured by KJ Chemicals, monofunctional monomer) VCAP: vinylcaprolactam (manufactured by BASF Japan Ltd., monofunctional monomer) Viscoat 160: benzyl acrylate (manufactured by Osaka Organic Chemical Industry Ltd., monofunctional acrylate) LA: lauryl acrylate (manufactured by Osaka Organic Chemical Industry Ltd., monofunctional acrylate) TPGDA: tripropylene glycol diacrylate (Osaka Organic Chemical Industry Co., Ltd., bifunctional acrylate) A-NOD-N: 1,9-nonanediol diacrylate (Shin-Nakamura Chemical Co., Ltd., bifunctional acrylate) <Initiator> DAIDO UV-CURE 819: phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide) (Daido Chemical Industry Co., Ltd.) <Photosensitizer> Tinopal OBCO: 2,5-bis(5'-t-butylbenzoxazolyl-2')thiophene (BASF Japan Ltd.) Chemark DETX: 2,4-diethylthioxanthone (CHEMARK CHEMICAL) <Polymerization inhibitor> Polystop 7300P: piperidine derivative (Hakuto Co., Ltd.) TEMPO: 2,2,6,6-tetramethylpiperidine 1-oxyl (manufactured by Sun Chemical Co., Ltd.) H-BHT: dibutylhydroxytoluene (manufactured by Honshu Chemical Industry Co., Ltd.) TBHQ FINE: t-butylhydroquinone (manufactured by Kusumoto Chemicals Co., Ltd.) Q-1301: N-nitroso-N-phenylhydroxylamine aluminum (manufactured by Wako Pure Chemical Industries, Ltd.) Adekastab 260: 4,4'-butylidenebis(3-methyl-6-t-butylphenyl-di-tridecylphosphite) (manufactured by ADEKA Corporation)

[0059] Example 1 The coating composition of Example 1 was prepared by mixing the components according to the formulation shown in Table 2 and stirring and mixing them at 60°C for 30 minutes using a disper. The viscosity, coatability, adhesion, curability, and fluorescent lamp stability of the resulting coating composition were evaluated using the following evaluation methods. The results are shown in Table 2.

[0060] Examples 2 to 11, Comparative Examples 1 to 20 Coating compositions were prepared and evaluated in the same manner as in Example 1, except that the formulations were changed as shown in Tables 2 to 4. The results are shown in Tables 2 to 4.

[0061] <Conditions for checking paint performance> (Viscosity) Using a rheometer Discovery HR-2 manufactured by TA Instruments, at 25°C and a shear rate of 100 s -1 The measurement was carried out under the following conditions. (Fluorescent Light Stability) The presence or absence of gelation at 25°C under a three-wavelength daylight fluorescent lamp at 1 m (825 lux) was evaluated according to the following evaluation criteria: ○: The coating composition did not gel for 5 hours or more. △○: The coating composition gelled in 3 hours or more but less than 5 hours. △: The coating composition gelled in 1 hour or more but less than 3 hours. ×: The coating composition gelled in less than 1 hour.

[0062] <Conditions for checking coating film performance> (Conditions for producing test pieces) Printed items 1 to 3 were produced by electrophotography using printing machines commonly used in this field from the following three companies. Each of the obtained electrophotographic printed items 1 to 3 was coated with a coating composition using bar coater #5, and then exposed to LED-UV (385 nm) UVA integrated light intensity of 300 mJ / cm. 2The coating composition was irradiated with ultraviolet light under the following conditions and cured. Electrophotographic Printed Material 1 (using a printing machine manufactured by HP) Electrophotographic Printed Material 2 (using a printing machine manufactured by RICOH) Electrophotographic Printed Material 3 (using a printing machine manufactured by CANON) (Coatability) The coating composition was applied to the printed material using a bar coater #5, and the leveling was evaluated according to the following evaluation criteria. ○: Smooth and good leveling. △○: Slight flow lines (a phenomenon in which coating streaks (unevenness) occur along the coating direction), repelling (a phenomenon in which circular unevenness occurs), and penetration into the paper were observed. △: Slight flow lines, repelling, and penetration into the paper were observed. ×: Flow lines, repelling, and penetration into the paper were observed over the entire surface, and leveling was poor. (Gloss Value) The 60° reflected gloss value of the coated surface of the test piece was determined using a VG8000 gloss meter manufactured by Nippon Denshoku Industries Co., Ltd. (Curing Property) The test pieces prepared by the above method were evaluated for dryness to the touch according to the following evaluation criteria. ○: The coating film was not tacky. △○: The coating film was slightly tacky. △: The coating film was tacky. ×: The coating film left a finger mark when touched. (Adhesion) The test pieces prepared by the above method were evaluated for adhesion to various printed materials 1 to 3 (printed using printers manufactured by HP, RICOH, and CANON) by attaching a 12 mm wide adhesive tape (Cellophane tape manufactured by Nichiban Co., Ltd.) to the test piece and peeling it off at an angle of 90° to the test piece according to the following evaluation criteria: ○: The coating film did not peel off. △○: The coating film had a coating film remaining rate of 70% or more. △: The coating film had a coating film remaining rate of 30 to 69%. ×△: The coating film had a coating film remaining rate of 1 to 29%. ×: The coating film peeled off entirely.

[0063]

[0064]

[0065]

[0066] As shown in Tables 2 to 4, it was found that the coating compositions of Examples 1 to 11 of the present invention exhibited excellent adhesion and were capable of imparting excellent gloss.

Claims

1. An active energy ray curable coating composition comprising: a resin, an ethylenically unsaturated compound, an initiator, and a polymerization inhibitor; the resin comprises an amine-modified styrene (meth)acrylic resin; the content of the amine-modified styrene (meth)acrylic resin is 5 to 30 mass %; the ethylenically unsaturated compound comprises at least one of acryloylmorpholine and vinylcaprolactam; the total content of at least one of the acryloylmorpholine and vinylcaprolactam is 41 mass % or more; the polymerization inhibitor comprises a piperidine derivative; the content of the piperidine derivative is 0.05 to 1 mass %; and the viscosity at 25°C is 40 to 380 mPa·s.

2. The active energy ray-curable coating composition according to claim 1, wherein the content of the amine-modified styrene (meth)acrylic resin is 15 to 25 mass %.

3. The active energy ray-curable coating composition according to claim 1 or 2, having a viscosity at 25° C. of 40 to 299 mPa·s.

4. An active energy ray-curable coating composition according to claim 1 or 2, which is applied to a printed matter printed by an electrophotographic method.

5. A coated printed material, comprising the active energy ray-curable coating composition according to claim 1 or 2 applied to a printed material printed by an electrophotographic method.

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