WO2020121534A1 - Styrene-acrylate copolymer - Google Patents

Abstract

The purpose of the present invention is to provide: a styrene-acrylate copolymer that makes it possible to obtain excellent physical properties when used in an ink; and an active energy ray-curable composition containing the copolymer.　The present invention is a styrene-acrylate copolymer characterized in that the ratio of a constituent unit (A) derived from a styrene compound is 10-90 mol%, the ratio of a constituent unit (B) derived from an acrylate compound is 10-90 mol%, and the constituent unit (B) derived from an acrylate compound includes a constituent unit (b-1) derived from a compound having at least three acryloyl groups per molecule thereof.

Description

Styrene-acrylate copolymer

The present invention relates to a styrene-acrylate copolymer, an active energy ray-curable resin composition containing a styrene-acrylate copolymer, and an ink and a paint containing the resin composition.

Conventionally, such as printed matter for forms, printed matter for various books, printed matter for various packaging such as carton paper, various printed matter for plastics, sticker, printed matter for labels, printed matter for art, printed matter for metal (printed matter for food, printed food for canned food, etc.) In order to obtain various printed matter, various printing methods such as lithographic printing (normal lithographic printing with dampening water and waterless lithographic printing without dampening water), letterpress, intaglio, stencil printing are used. The appropriate ink is used. Active energy ray-curable ink is known as one of such inks.

In recent years, the use of active energy ray-curable ink that is quick-drying and does not use a solvent is expanding in place of the oil-based ink that has been used in the past due to the shortening of printing deadlines and increasing demands for environmental friendliness. Among them, printing has been speeded up, and further speeding up of printing has been desired. For high-speed printing, it is necessary to increase the curing speed (drying property) of the printed film. As a method for this, a polyfunctional monomer with a high unsaturated group concentration of the compound having an ethylenically unsaturated double bond is used. Alternatively, a method using a high-performance photopolymerization initiator or a photosensitizer is used (Patent Document 1). However, although it is possible to increase the curing rate of the film by using a polyfunctional monomer having a high unsaturated group concentration in the compound, the cost of the compound is high and it cannot be said to be an industrially practical method. .. Further, the method using a high-performance photopolymerization initiator also has a problem of high cost. Therefore, development of an active energy ray-curable composition having excellent film curing rate (drying property) and strong film strength using methods other than these methods has been earnestly desired.

Furthermore, in Patent Documents 2 and 3, the weight average molecular weight (Mw) obtained by copolymerizing a monomer component containing styrenes, (meth)acrylic acid alkyl ester and a hydrophilic group-containing vinyl monomer is 5,000 to Active energy ray curable resin having a glass transition temperature (Tg) of 13,000 and an active energy ray curable resin (A) having a glass transition temperature (Tg) of 70 to 100° C. and a reactive diluent (B). Wet offset printing inks are described. However, since the component (meth)acrylic acid alkyl ester used as the component in the copolymer has one acryloyl group, sufficient dryness cannot be obtained and scratch resistance is poor.

Development of an active energy ray-curable composition that is excellent in various physical properties required for use in inks or paints (drying property, scratch resistance, etc.) is required.

JP-A-7-11166 Japanese Patent No. 5403219 Patent No. 5598648

An object of the present invention is to provide a styrene-acrylate copolymer that can obtain excellent physical properties when used in an ink or a paint, and an active energy ray-curable composition containing the copolymer.

As a result of earnest research to solve the above problems, a specific styrene-acrylate copolymer and an active energy ray-curable composition containing the copolymer have various physical properties (dry property) required when used in ink. The present invention has been completed by discovering that it has excellent heat resistance and scratch resistance).

That is, the present invention can be described as follows.

Item 1. A styrene-acrylate copolymer,
The ratio of the structural unit (A) derived from the styrene compound is 10 to 90 mol%, the ratio of the structural unit (B) derived from the acrylate compound is 10 to 90 mol%, and the structural unit derived from the acrylate compound (B) is characterized by containing a structural unit (b-1) derived from a compound having at least three or more acryloyl groups in the molecule.
Item 2. Item 2. The styrene-acrylate copolymer according to Item 1, wherein the compound having at least three acryloyl groups in the molecule is an acrylate compound having three acryloyl groups and an acrylate compound having four acryloyl groups.
Item 3. The compound having at least three or more acryloyl groups in the molecule is trimethylolpropane tri(meth)acrylate, trimethyloloctanetri(meth)acrylate, trimethylolpropane polyethoxytri(meth)acrylate, trimethylolpropane polypropoxytril. (Meth)acrylate, trimethylolpropane polyethoxypolypropoxytri(meth)acrylate, tris[(meth)acryloyloxyethyl]isocyanurate, pentaerythritol tri(meth)acrylate, pentaerythritol polyethoxytetra(meth)acrylate, pentaerythritol Item 3. The styrene according to Item 1 or 2, which is one kind selected from polypropoxytetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, and dipentaerythritol tetra(meth)acrylate. Acrylate copolymer.
Item 4. Item 1. The structural unit (B) derived from an acrylate compound further contains a structural unit (b-2) derived from an aromatic acrylate compound and a structural unit (b-3) derived from an aliphatic acrylate compound. The styrene-acrylate copolymer according to any one of 1.
Item 5. Item 5. The styrene-acrylate copolymer according to any one of Items 1 to 4, wherein the styrene-acrylate copolymer has a molecular weight distribution (weight average molecular weight (Mw)/number average molecular weight (Mn)) of 1 to 50.
Item 6. 6. The styrene-acrylate copolymer according to any one of Items 1 to 5, wherein the styrene-acrylate copolymer has an iodine value of 1 to 100.
Item 7. Item 7. An active energy ray-curable composition comprising the styrene-acrylate copolymer according to any one of items 1 to 6.
Item 8. Item 8. The active energy ray-curable composition according to Item 7, further containing a monomer having a radical-polymerizable double bond.
Item 9. Item 9. An ink comprising the composition according to Item 7 or 8.
Item 10. Item 9. A paint comprising the composition according to Item 7 or 8.
Item 11. Item 11. The paint according to Item 10, which is an overprint varnish.

According to the present invention, an active energy ray-curable composition containing a styrene-acrylate copolymer is used in an ink or paint, whereby an ink or paint excellent in various physical properties (drying property, scratch resistance) can be obtained.

Styrene-Acrylate Copolymer The styrene-acrylate copolymer of the present invention will be described below.

The styrene-acrylate copolymer of the present invention is a styrene-acrylate copolymer in which the ratio of the structural unit (A) derived from the styrene compound is 10 to 90 mol% and the structural unit derived from the acrylate compound is The ratio of (B) is 10 to 90 mol %, and the structural unit (B) derived from an acrylate compound is a structural unit (b-1) derived from a compound having at least three or more acryloyl groups in the molecule. It is characterized by including.

In the styrene-acrylate copolymer of the present invention, the proportion of the structural unit (A) derived from the styrene compound may be 10 to 90 mol %, preferably 20 to 80 mol %, and 20 to 50 mol %. % Is more preferable. Further, the ratio of the structural unit (B) derived from the acrylate compound may be 10 to 90 mol %, preferably 20 to 80 mol %, and more preferably 50 to 80 mol %.

Structural unit (A) derived from styrene compound
The structural unit (A) derived from the styrene compound in the styrene-acrylate copolymer of the present invention is not particularly limited, and examples thereof include styrene; methylstyrene, α-methylstyrene, β-methylstyrene, p-methylstyrene. , Alkyl-substituted styrenes such as tert-butylstyrene; halogen-substituted styrenes such as 4-chlorostyrene, 4-bromostyrene, chloromethylstyrene; p-hydroxystyrene, α-methyl-p-hydroxystyrene, 2-methyl- Hydroxystyrenes such as 4-hydroxystyrene and 3,4-dihydroxystyrene; vinylbenzyl alcohols; alkoxy-substituted styrenes such as p-methoxystyrene, p-tert-butoxystyrene, m-tert-butoxystyrene; 3-vinyl Vinylbenzoic acids such as benzoic acid and 4-vinylbenzoic acid; 4-vinylbenzyl acetate; 4-acetoxystyrene; amide styrenes such as 2-butylamidostyrene, 4-methylamidostyrene and p-sulfonamidostyrene; 3- Aminostyrenes such as aminostyrene, 4-aminostyrene, 2-isopropenylaniline and vinylbenzyldimethylamine; nitrostyrenes such as 3-nitrostyrene and 4-nitrostyrene; 3-cyanostyrene, 4-cyanostyrene and the like Examples include cyanostyrenes; vinylphenylacetonitrile; arylstyrenes such as phenylstyrene, indenes, and the like. Among them, styrene; alkyl-substituted styrenes such as methylstyrene, α-methylstyrene, β-methylstyrene, p-methylstyrene and tert-butylstyrene; halogen-substituted styrenes such as 4-chlorostyrene, 4-bromostyrene and chloromethylstyrene. Preferred are hydroxystyrenes such as p-hydroxystyrene, α-methyl-p-hydroxystyrene, 2-methyl-4-hydroxystyrene and 3,4-dihydroxystyrene, and styrene; methylstyrene, α-methylstyrene, β Alkyl-substituted styrenes such as -methylstyrene, p-methylstyrene and tert-butylstyrene are more preferable.

Structural unit (B) derived from acrylate compound
The constituent unit (B) derived from the acrylate compound in the styrene-acrylate copolymer of the present invention may be a constituent unit (b-1) derived from a compound having at least three or more acryloyl groups in the molecule. Good.

As the structural unit (b-1) derived from a compound having at least three or more acryloyl groups in the molecule, an acrylate compound having three acryloyl groups and an acrylate compound having four acryloyl groups may be used. Include trimethylolpropane tri(meth)acrylate, trimethyloloctane tri(meth)acrylate, trimethylolpropane polyethoxytri(meth)acrylate, trimethylolpropane polypropoxytri(meth)acrylate, trimethylolpropane polyethoxypolypropoxy. Tri(meth)acrylate, tris[(meth)acryloyloxyethyl]isocyanurate, pentaerythritol tri(meth)acrylate, pentaerythritol polyethoxytetra(meth)acrylate, pentaerythritol polypropoxytetra(meth)acrylate, pentaerythritol tetra( (Meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate are preferable, and trimethylolpropane tri(meth)acrylate is preferable. More preferred are trimethylolpropane polyethoxytri(meth)acrylate, trimethylolpropane polypropoxytri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, and ditrimethylolpropane tetra(meth)acrylate. ..

The structural unit (B) derived from the acrylate compound may further include a structural unit (b-2) derived from the aromatic acrylate compound and a structural unit (b-3) derived from the aliphatic acrylate compound. Good. It should be noted that the aromatic acrylate compound and the aliphatic acrylate compound do not include compounds having at least three or more acryloyl groups in the molecule.

A structural unit (B) derived from an acrylate compound, a structural unit (b-1) derived from a compound having at least three acryloyl groups in the molecule, and a structural unit (b-2) derived from an aromatic acrylate compound. ) And a structural unit (b-3) derived from an aliphatic acrylate compound, the ratio of each structural unit ((b-1):(b-2):(b-3)) is 1 to 4: It may be in the range of 1 to 5:1 to 4, and is preferably in the range of 1 to 3:1 to 4:1 to 3.

The constitutional unit (b-2) derived from an aromatic acrylate compound is an aromatic acrylate compound having one or two acryloyl groups in the molecule (preferably, an aromatic acrylate compound having one acryloyl group in the molecule). ), specifically, benzyl (meth)acrylate, phenyl (meth)acrylate, phenoxyethyl (meth)acrylate, phenoxypolyethylene glycol (meth)acrylate, biphenyl (meth)acrylate, nonylphenyl (meth)acrylate. , Nonylphenoxyethyl (meth)acrylate, nonylphenoxypolyethylene glycol (meth)acrylate, cumylphenol (meth)acrylate, cumylphenoxyethyl (meth)acrylate, cumylphenoxypolyethyleneglycol (meth)acrylate, o-phenylphenol ( Examples thereof include (meth)acrylate, ethoxylated o-phenylphenol(meth)acrylate, tribromophenyl(meth)acrylate, and EO-modified tribromophenyl(meth)acrylate. Among them, benzyl (meth)acrylate and phenoxyethyl (meth)acrylate are preferable.

As the structural unit (b-3) derived from the aliphatic acrylate compound, an aliphatic acrylate compound having one or two acryloyl groups in the molecule (preferably an aliphatic acrylate compound having one acryloyl group in the molecule ), specifically, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate , Hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, isononyl (meth)acrylate, isopentyl (meth)acrylate, tridecyl (meth)acrylate, stearyl (meth)acrylate, lauryl (meth)acrylate Etc. can be illustrated. Of these, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and isooctyl (meth)acrylate are preferable.

The structural unit (B) derived from the acrylate compound in the styrene-acrylate copolymer may further include a structural unit (b-4) derived from another acrylate compound. In this case, the ratio of the structural unit (b-4) derived from the other acrylate compound in the structural unit (B) derived from the acrylate compound is such that it is derived from a compound having at least three acryloyl groups in the molecule. Unit (b-1), structural unit (b-2) derived from aromatic acrylate compound, and structural unit (b-3) derived from aliphatic acrylate compound: structural unit (b derived from other acrylate compound -4), it may be in the range of 100:0 to 80:20, and preferably in the range of 100:0 to 90:10.

When the structural unit (B) derived from the acrylate compound in the styrene-acrylate copolymer of the present invention further contains a structural unit (b-4) derived from the other acrylate compound, the other acrylate compound is as described above. A compound having at least three acryloyl groups in the molecule, an aromatic acrylate compound, and an aliphatic acrylate compound are not included.

Examples of other acrylate compounds include compounds having at least three or more acryloyl groups in the molecule described above, aromatic acrylate compounds, monofunctional acrylates other than aliphatic acrylate compounds, and bifunctional acrylates.

Examples of the monofunctional acrylate include (meth)acrylate of ethylene oxide adduct, isobornyl (meth)acrylate, cyclohexyl (meth)acrylate, tricyclodecane monomethylol (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2- Hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, hydroxypentyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl ( (Meth)acrylate, 2-hydroxy-3-butoxypropyl (meth)acrylate, 2-hydroxy-3-methoxypropyl (meth)acrylate, diethylene glycol mono(meth)acrylate, triethylene glycol mono(meth)acrylate, polyethylene glycol mono( (Meth)acrylate, dipropylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, glycerin mono(meth)acrylate, acryloxyethyl phthalate, 2-(meth)acryloyloxyethyl-2-hydroxyethyl phthalate, 2 -(Meth)acryloyloxypropyl phthalate, β-carboxyethyl(meth)acrylate, (meth)acrylic acid dimer, ω-carboxy-polycaprolactone mono(meth)acrylate, dimethylaminoethyl(meth)acrylate, diethylaminoethyl(meth ) Acrylate, (meth)acryloylmorpholine and the like are exemplified.

As the bifunctional acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene 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, butylene glycol di(meth)acrylate, pentyl glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, hydroxypivalyl hydroxy Pivalate di(meth)acrylate, hydroxypivalyl hydroxypivalate dicaprolactonate di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,2-hexanediol di(meth)acrylate, 1, 5-hexanediol di(meth)acrylate, 2,5-hexanediol di(meth)acrylate, 1,7-heptanediol di(meth)acrylate, 1,8-octanediol di(meth)acrylate, 1,2- Octanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,2-decanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, 1,12-dodecanediol Di(meth)acrylate, 1,2-dodecanediol di(meth)acrylate, 1,14-tetradecanediol di(meth)acrylate, 1,2-tetradecanediol di(meth)acrylate, 1,16-hexadecanediol di( (Meth)acrylate, 1,2-hexadecanediol di(meth)acrylate, 2-methyl-2,4-pentanediol di(meth)acrylate, 3-methyl-1,5-pentanediol di(meth)acrylate, 2- Methyl-2-propyl-1,3-propanediol di(meth)acrylate, 2,4-dimethyl-2,4-pentanediol di(meth)acrylate, 2,2-diethyl-1,3-propanedioldi (Meth)acrylate, 2,2,4-trimethyl-1,3-pentanediol di(meth)acrylate, dimethyloloctane di(meth)acrylate, 2-ethyl-1,3-hexanediol di(meth)acrylate, 2,5-dimethyl-2,5-hexanediol di( (Meth)acrylate, 2-methyl-1,8-octanediol di(meth)acrylate, 2-butyl-2-ethyl-1,3-propanediol di(meth)acrylate, 2,4-diethyl-1,5- Pentanediol di(meth)acrylate, tricyclodecane dimethylol di(meth)acrylate, tricyclodecane dimethylol dicaprolactonate di(meth)acrylate, bisphenol A tetraethylene oxide adduct di(meth)acrylate, bisphenol F tetra Ethylene oxide adduct di(meth)acrylate, bisphenol S tetraethylene oxide adduct di(meth)acrylate, water-added bisphenol A tetraethylene oxide adduct di(meth)acrylate, water-added bisphenol F tetraethylene oxide adduct di(meth) ) Acrylate, water-added bisphenol A di(meth)acrylate, water-added bisphenol F di(meth)acrylate, bisphenol A tetraethylene oxide adduct dicaprolactonate di(meth)acrylate, bisphenol F tetraethylene oxide adduct dicaprolactate Examples thereof include natedi(meth)acrylate.

Among them, (meth)acryloylmorpholine is preferable.

When the structural unit (B) derived from the acrylate compound in the styrene-acrylate copolymer contains the structural unit (b-4) derived from the other acrylate compound, the structural unit (b-derived from the other acrylate compound The ratio of 4) may be in the range of 0 mol% to 20 mol% in the entire constitutional unit (B) derived from the acrylate compound, and is preferably in the range of 0 mol% to 10 mol %.

The styrene-acrylate copolymer may further contain a structural unit (C) derived from a carboxylic acid. When the structural unit (C) derived from a carboxylic acid is contained, the ratio of the structural unit (C) derived from a carboxylic acid may be in the range of 0 to 20 mol%, and is in the range of 0 to 10 mol%. Preferably.

The carboxylic acid may be any unsaturated aliphatic carboxylic acid, and (meth)acrylic acid, maleic acid, itaconic acid and the like are preferable.

The molecular weight distribution (weight average molecular weight (Mw)/number average molecular weight (Mn)) of the styrene-acrylate copolymer may be in the range of 1 to 50, and is preferably in the range of 1 to 40. The range is more preferably.

The number average molecular weight (Mn) of the styrene-acrylate copolymer may be 1,000 to 100,000, preferably 1,000 to 50,000, and more preferably 1,000 to 30,000. The weight average molecular weight (Mw) of the styrene-acrylate copolymer is not particularly limited, but may be 1,000 to 500,000, preferably 1,000 to 400,000, and 1,000 to 300,000. More preferable. In the present specification, the “number average molecular weight” and the “weight average molecular weight” are measured at 40° C. by gel permeation chromatography (Prominence-i, LC-2030 manufactured by Shimadzu Corp.) to obtain standard polystyrene. It is obtained using a calibration curve. The iodine value of the styrene-acrylate copolymer may be 1 to 100, preferably 1 to 80, and more preferably 1 to 50.

The polymerization reaction for obtaining the styrene-acrylate copolymer can be synthesized by a known method using the above raw materials. Various conditions in this synthesis must be appropriately set according to the raw material used and the amount thereof. In this polymerization reaction, a catalyst can be used if necessary. Examples of the catalyst include azobisisobutyronitrile, azo initiators such as dimethyl 2,2'-azobisisobutyrate, ketone peroxides, peroxyketals, hydroperoxides, dialkyl peroxides, diacyl peroxides. , Peroxyesters and other peroxide initiators, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 1-hydroxycyclohexylphenyl ketone and other acetophenone-based compounds, Examples of known catalysts include benzoin-based compounds such as benzoin and benzoin ethyl ether, benzophenone-based compounds such as benzophenone, phosphorus-based compounds such as acylphosphine oxide, and sulfur-based compounds such as thioxanthone.

Specific examples of the ketone peroxides include methyl ethyl ketone peroxide, methyl isobutyl ketone peroxide, acetylacetone peroxide, cyclohexanone peroxide, and methylcyclohexanone peroxide.

Specific examples of hydroperoxides include, for example, 1,1,3,3-tetramethylbutyl hydroperoxide, cumene hydroperoxide, tert-butyl hydroperoxide, p-menthane hydroperoxide, and diisopropylbenzene hydroperoxide. Examples include peroxides.

Specific examples of the diacyl peroxides include, for example, diisobutyryl peroxide, bis-3,5,5-trimethylhexanol peroxide, dilauroyl peroxide, dibenzoyl peroxide, m-toluylbenzoyl peroxide, and succinic acid. Examples include peroxides.

Specific examples of the dialkyl peroxides include dicumyl peroxide, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 1,3-bis(tert-butylperoxyisopropyl)hexane, Mention may be made of tert-butyl cumyl peroxide, di-tert-butyl peroxide, di-tert-hexyl peroxide, and 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexyne-3.

Specific examples of peroxyketals include, for example, 1,1-bis(tert-hexylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-hexylperoxy)cyclohexane, 1, 1-bis(tert-butylperoxy)-2-methylcyclohexane, 1,1-bis(tert-butylperoxy)cyclohexane, 2,2-bis(tert-butylperoxy)butane, and 4,4-bis Examples thereof include butyl (tert-butylperoxy)pentanoate and 1,1-di(tert-hexylperoxy)cyclohexane.

Specific examples of the alkyl peresters (peroxy esters) include, for example, 1,1,3,3-tetramethylbutyl peroxy neodecanoate, α-cumylperoxy neodecanoate, and tert-butyl perester. Oxy neodecanoate, tert-hexyl peroxy neo decanoate, tert-butyl peroxy neo heptanoate, tert-hexyl peroxy pivalate, tert-butyl peroxy pivalate, 1,1,3,3- Tetramethylbutylperoxy-2-ethylhexanoate, tert-amylperoxy-2-ethylhexanoate, tert-butylperoxy-2-ethylhexanoate, tert-butylperoxyisobutyrate, di- tert-butylperoxyhexahydroterephthalate, 1,1,3,3-tetramethylbutylperoxy-3,5,5-trimethylhexanate, tert-amylperoxy 3,5,5-trimethylhexanoate, tert -Butylperoxy-3,5,5-trimethylhexanoate, tert-butylperoxyacetate, tert-butylperoxybenzoate, dibutylperoxytrimethyl adipate, 2,5-dimethyl-2,5-di-2- Ethyl hexanoyl peroxyhexane, tert-hexyl peroxy-2-ethyl hexanoate, tert-hexyl peroxy isopropyl monocarbonate, tert-butyl peroxy laurate, tert-butyl peroxy isopropyl monocarbonate, tert-butyl per Examples include oxy-2-ethylhexyl monocarbonate, and 2,5-dimethyl-2,5-di-benzoylperoxyhexane, tert-hexylperoxybenzoate, tert-hexylperoxy-acetic acid ester.

The order of adding the raw materials used for the reaction of the styrene-acrylate copolymer of the present invention may be such that after all the raw materials used for the reaction are added to the reaction vessel, the polymerization reaction may be started by heating, and a part of the reaction may be performed first. The polymerization reaction may be carried out while adding it to the vessel and heating and then dropping the rest.After adding the solvent to the reaction vessel and heating, the polymerization reaction is carried out while dropping the mixture of the raw materials used in the reaction. May be. Further, the amount of the catalyst used for the reaction of the styrene-acrylate copolymer of the present invention may be appropriately adjusted, and may be 10.0 parts by weight or less based on 100 parts by weight of the components used for the polymerization reaction. It is preferably not more than 0.0 parts by weight. Further, it is more preferably 0.001 to 8.0 parts by weight.

In the polymerization reaction, a solvent may be used if necessary. When a solvent is used, it is preferably used within the range of 80% by weight or less based on the total amount of the reaction solution.

Examples of the solvent include alcohols such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol and n-butyl alcohol, acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl isopropyl ketone, methyl-n-butyl ketone, Methyl isobutyl ketone, methyl-n-amyl ketone, methyl isoamyl ketone, diethyl ketone, ethyl-n-propyl ketone, ethyl isopropyl ketone, ethyl-n-butyl ketone, ethyl isobutyl ketone, di-n-propyl ketone, diisobutyl ketone, cyclohexanone, Ketones such as methylcyclohexanone and isophorone, esters such as methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, hexyl acetate, octyl acetate, methyl lactate, propyl lactate and butyl lactate , Ethylene glycol, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether , Propylene glycol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dipropyl ether, tripropylene glycol monomethyl ether Glycols and glycol ethers such as ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, Propylene glycol monoethyl ether acetate, propylene glycol monobutyl ether acetate, dipropylene glycol Glycol acetates such as monomethyl ether acetate, saturated hydrocarbons such as n-hexane, isohexane, n-nonane, isononane, dodecane and isododecane, unsaturated hydrocarbons such as 1-hexene, 1-heptene and 1-octene , Cyclohexane, cycloheptane, cyclooctane, cyclodecane, decalin, etc., cyclic saturated hydrocarbons, γ-butyrolactone, δ-valerolactone, etc., cyclic esters, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, etc. Cyclic unsaturated hydrocarbons such as nitrogen-containing heterocycles, cyclohexene, cycloheptene, cyclooctene, 1,1,3,5,7-cyclooctatetraene and cyclododecene, aromatic carbonization such as benzene, toluene, xylene and mesitylene Examples thereof include hydrogens. These organic solvents may be used alone or in combination of two or more.

The reaction atmosphere is preferably an inert gas atmosphere such as nitrogen or argon. The reaction pressure may be either atmospheric pressure or increased pressure, but it is preferably atmospheric pressure in view of workability. The reaction can be carried out by charging the raw materials once or in a divided manner into a reactor equipped with a stirring blade and then reacting them at a predetermined temperature. The reaction temperature during the polymerization is preferably 60 to 240°C, for example 80 to 220°C. The reaction time is preferably 0.1 to 100 hours, for example 0.5 to 30 hours.

Active energy ray-curable composition The active energy ray-curable composition of the present invention contains the above-mentioned styrene-acrylate copolymer, and optionally contains a monomer having a radical-polymerizable double bond and a polymerization initiator. It includes.

The content of the styrene-acrylate copolymer in the active energy ray-curable composition may be in the range of 1 to 50% by weight, preferably in the range of 1 to 40% by weight.

As a method for obtaining the active energy ray-curable composition of the present invention, a styrene-acrylate copolymer, if necessary, a monomer having a radical-polymerizable double bond, and a polymerization initiator are mixed, and the temperature is set to 25 to 120° C. It can be obtained by dissolving in an air atmosphere for 0.5 to 2 hours.

The content of the monomer having a radical-polymerizable double bond in the resin composition of the present invention is 40 to 90% by weight, preferably 50 to 90% by weight.

As the monomer having a radical-polymerizable double bond in the active energy ray-curable composition of the present invention, a compound containing a (meth)acrylate group can be exemplified, and specifically, the following can be exemplified.

Examples of monofunctional acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, hexyl (meth)acrylate, octyl (meth)acrylate, dodecyl (meth)acrylate and stearyl (meth)acrylate. There are alkyl (meth)acrylates having 1 to 18 carbon atoms, and further benzyl (meth)acrylate, isobornyl (meth)acrylate, cyclohexyl (meth)acrylate, tricyclodecane monomethylol (meth)acrylate, 2-hydroxyethyl ( (Meth)acrylate, 2-hydroxypropyl(meth)acrylate, 3-hydroxypropyl(meth)acrylate, 2-hydroxybutyl(meth)acrylate, 4-hydroxybutyl(meth)acrylate, hydroxypentyl(meth)acrylate, 2-hydroxy -3-phenoxypropyl (meth)acrylate, 2-hydroxy-3-butoxypropyl (meth)acrylate, 2-hydroxy-3-methoxypropyl (meth)acrylate, diethylene glycol mono(meth)acrylate, triethylene glycol mono(meth)acrylate Acrylate, polyethylene glycol mono(meth)acrylate, dipropylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, glycerin mono(meth)acrylate, acryloxyethyl phthalate, 2-(meth)acryloyloxyethyl-2 -Hydroxyethyl phthalate, 2-(meth)acryloyloxypropyl phthalate, β-carboxyethyl (meth)acrylate, (meth)acrylic acid dimer, ω-carboxy-polycaprolactone mono(meth)acrylate, dimethylaminoethyl (meth) Acrylate, diethylaminoethyl (meth)acrylate, (meth)acryloylmorpholine and the like are exemplified.

Furthermore, as a bifunctional acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene 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, butylene glycol di(meth)acrylate, pentyl glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, hydroxypivalyl Hydroxypivalate di(meth)acrylate, hydroxypivalyl hydroxypivalate dicaprolactonate di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,2-hexanediol di(meth)acrylate, 1 ,5-hexanediol di(meth)acrylate, 2,5-hexanediol di(meth)acrylate, 1,7-heptanediol di(meth)acrylate, 1,8-octanediol di(meth)acrylate, 1,2 -Octanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,2-decanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, 1,12-dodecane Diol di(meth)acrylate, 1,2-dodecanediol di(meth)acrylate, 1,14-tetradecanediol di(meth)acrylate, 1,2-tetradecanediol di(meth)acrylate, 1,16-hexadecanediol di (Meth)acrylate, 1,2-hexadecanediol di(meth)acrylate, 2-methyl-2,4-pentanediol di(meth)acrylate, 3-methyl-1,5-pentanediol di(meth)acrylate, 2 -Methyl-2-propyl-1,3-propanediol di(meth)acrylate, 2,4-dimethyl-2,4-pentanediol di(meth)acrylate, 2,2-diethyl-1,3-propanedio- Rudi(meth)acrylate, 2,2,4-trimethyl-1,3-pentanediol di(meth)acrylate, dimethyloloctane di(meth)acrylate, 2-ethyl-1,3-hexanediol di(meth)acrylate 2,5-dimethyl-2,5-hexanedio Rudi(meth)acrylate, 2-methyl-1,8-octanediol di(meth)acrylate, 2-butyl-2-ethyl-1,3-propanediol di(meth)acrylate, 2,4-diethyl-1, Examples include 5-pentanediol di(meth)acrylate, tricyclodecane dimethylol di(meth)acrylate, tricyclodecane dimethylol dicaprolactonate di(meth)acrylate, and the like.

Trifunctional acrylate glycerin tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolpropane tricaprolactonate tri(meth)acrylate, trimethylolethane tri(meth)acrylate, trimethylolhexane tri(meth)acrylate , Trimethylol octane tri(meth)acrylate, pentaerythritol tri(meth)acrylate and the like.

Pentaerythritol tetra(meth)acrylate, pentaerythritol tetracaprolactonate tetra(meth)acrylate, diglycerin tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, ditrimethylolpropane tetracapro as a tetrafunctional or higher functional acrylate. Lactonate tetra(meth)acrylate, ditrimethylolethane tetra(meth)acrylate, ditrimethylol butane tetra(meth)acrylate, ditrimethylol hexane tetra(meth)acrylate, ditrimethylol octane tetra(meth)acrylate, dipentaerythritol penta(meth) ) Acrylate, dipentaerythritol hexa(meth)acrylate, tripentaerythritol hexa(meth)acrylate, tripentaerythritol hepta(meth)acrylate, tripentaerythritol octa(meth)acrylate, tripentaerythritol polyalkylene oxide hepta(meth)acrylate Etc. are illustrated.

Further, as the compound containing a (meth)acrylic group, an alkylene oxide adduct (meth)acrylate of an aliphatic alcohol compound can be exemplified.
Alkylene oxide adduct of aliphatic alcohol compound (meth)acrylate Mono- or poly(1-20) alkylene (C2-C20) oxide adduct of aliphatic alcohol compound as a monomer (eg, alkylene oxide such as ethylene oxide, propylene oxide, butylene oxide) , Pentylene oxide, hexylene oxide, etc.) mono- or poly(1-10)(meth)acrylate. More specifically, monofunctional modified acrylate, difunctional modified acrylate, trifunctional modified acrylate, tetrafunctional modified acrylate and the like can be mentioned.

As the monofunctional modified acrylate, an alkylene oxide adduct (meth)acrylate having a carbon number of 2 to 20, for example, methanol mono- or poly(1-20) alkylene (C2 to C20) oxide adduct (for example, ethylene oxide or propylene oxide as the alkylene oxide) is used. , Butylene oxide) (meth) acrylate, ethanol mono- or poly(1-20) alkylene (C2-C20) oxide adduct (as alkylene oxide, for example, ethylene oxide, propylene oxide, butylene oxide) (meth) acrylate, butanol mono or poly (1-20) Alkylene (C2-C20) oxide adduct (eg, alkylene oxide such as ethylene oxide, propylene oxide, butylene oxide) (meth)acrylate, hexanol mono- or poly(1-20) alkylene (C2-C20) oxide addition Body (eg, alkylene oxide such as ethylene oxide, propylene oxide, butylene oxide) (meth)acrylate, octanol mono- or poly(1-20) alkylene (C2 to C20) oxide adduct (eg, alkylene oxide such as ethylene oxide, propylene oxide, butylene) Oxide) (meth)acrylate, dodecanol mono- or poly(1-20) alkylene (C2-C20) oxide adduct (as alkylene oxide, for example, ethylene oxide, propylene oxide, butylene oxide) (meth)acrylate, stearyl mono or poly (1-20) Alkylene (C2-C20) Oxide Adduct (Alkylene oxide includes, for example, ethylene oxide and propylene oxide. Further, poly(1-20) alkylene (C2-C20) oxide of butylphenol, octylphenol, nonylphenol or dodecylphenol. Examples thereof include adducts (ethylene oxide, propylene oxide, butylene oxide as alkylene oxide) (meth)acrylate and the like.

Furthermore, as a bifunctional modified acrylate, ethylene glycol mono- or poly(1-20) alkylene (C2-C20) oxide adduct (eg, alkylene oxide such as ethylene oxide, propylene oxide, butylene oxide) di(meth)acrylate, diethylene glycol mono- or poly( 2-20) Alkylene (C2-C20) oxide adduct (eg, alkylene oxide such as ethylene oxide, propylene oxide, butylene oxide) di(meth)acrylate, triethylene glycol poly(2-20) alkylene (C2-C20) oxide addition Body (as alkylene oxide, for example, ethylene oxide, propylene oxide, butylene oxide) di(meth)acrylate, polyethylene glycol poly(2-20) alkylene (C2-C20) oxide adduct (for example, as alkylene oxide, ethylene oxide, propylene oxide, Butylene oxide) di(meth)acrylate, propylene glycol poly(2-20) alkylene (C2-C20) oxide adduct (as alkylene oxide, for example, ethylene oxide, propylene oxide, butylene oxide) di(meth)acrylate, dipropylene glycol Poly(2 to 20) alkylene (C2 to C20) oxide adduct (eg, alkylene oxide such as ethylene oxide, propylene oxide, butylene oxide) di(meth)acrylate, tripropylene glycol poly(2 to 20) alkylene (C2 to C20) Oxide adducts (as alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide) di(meth)acrylate, polypropylene glycol poly(2-20) alkylene (C2-C20) oxide adducts (as alkylene oxides such as ethylene oxide, Propylene oxide, butylene oxide) di(meth)acrylate, butylene glycol poly(2-20) alkylene (C2-C20) oxide adduct (for example, as alkylene oxide, ethylene oxide, propylene oxide, butylene oxide) di(meth)acrylate, pentyl Glycol Poly(2-20) alkylene (C2-C20) oxide adduct (as alkylene oxide, for example, ethylene oxide, propylene oxide) Xide, butylene oxide) di(metaneopentyl glycol poly(2-20) (eg ethylene oxide, propylene oxide, butylene oxide, etc.) adduct di(meth)acrylate, hydroxypivalyl hydroxypivalate poly(2-20) alkylene (C2 to C20) oxide adduct (eg, alkylene oxide such as ethylene oxide, propylene oxide, butylene oxide) di(meth)acrylate (commonly called Manda), hydroxypivalyl hydroxypivalate dicaprolactonate poly(2-20) alkylene( C2 to C20) oxide adduct (eg, alkylene oxide such as ethylene oxide, propylene oxide, butylene oxide) di(meth)acrylate, 1,6 hexanediol poly(2 to 20)alkylene (C2 to C20) oxide adduct (alkylene oxide) As, for example, ethylene oxide, propylene oxide, butylene oxide) di(meth)acrylate, 1,6 hexanediol poly(2-20) alkylene oxide adduct (for example, ethylene oxide, propylene oxide, butylene oxide, etc.) di(meth)acrylate 1,2-hexanediol di(meth)acrylate, 1,5-hexanediol poly(2-20)alkylene (C2-C20) oxide adduct (as alkylene oxide, for example, ethylene oxide, propylene oxide, butylene oxide) di (Meth)acrylate, 2,5-hexanediol poly(2-20) alkylene(C2-C20) oxide adduct (as alkylene oxide, for example, ethylene oxide, propylene oxide, butylene oxide) di(meth)acrylate, 1,7- Heptanediol poly(2-20) alkylene(C2-C20) oxide adduct (as alkylene oxide, for example, ethylene oxide, propylene oxide, butylene oxide) di(meth)acrylate, 1,8-octanediol poly(2-20) Alkylene (C2-C20) oxide adduct (as alkylene oxide, for example, ethylene oxide, propylene oxide, butylene oxide) di(meth)acrylate, 1,2-octanediol poly(2-20) alkylene (C2-C20) oxide addition Body (as alkylene oxide such as ethylene oxide , Propylene oxide, butylene oxide) di(meth)acrylate di(meth)acrylate, 1,9-nonanediol poly(2-20)alkylene (C2-C20) oxide adduct (as alkylene oxide, for example, ethylene oxide, propylene Oxide, butylene oxide) di(meth)acrylate, 1,2-decanediol poly(2-20) alkylene (C2-C20) oxide adduct (eg, alkylene oxide such as ethylene oxide, propylene oxide, butylene oxide) di(meth) Acrylate, 1,10-decanediol poly(2-20) alkylene(C2-C20) oxide adduct (as alkylene oxide, for example, ethylene oxide, propylene oxide, butylene oxide) di(meth)acrylate, 1,2-decanediol Poly(2 to 20) alkylene (C2 to C20) oxide adduct (eg, alkylene oxide such as ethylene oxide, propylene oxide, butylene oxide) di(meth)acrylate, 1,12-dodecanediol poly(2 to 20) alkylene (C2) To C20) oxide adduct (as alkylene oxide, for example, ethylene oxide, propylene oxide, butylene oxide) di(meth)acrylate, 1,2-dodecanediol mono- or poly(1-20)alkylene (C2-C20) oxide adduct (As alkylene oxide, for example, ethylene oxide, propylene oxide, butylene oxide) di(meth)acrylate, 1,14-tetradecanediol poly(2-20) alkylene (C2-C20) oxide adduct (for example, as alkylene oxide, ethylene oxide, Propylene oxide, butylene oxide) di(meth)acrylate, 1,2-tetradecanediol poly(2-20) alkylene (C2-C20) oxide adduct (as alkylene oxide, for example, ethylene oxide, propylene oxide, butylene oxide) di( (Meth)acrylate, 1,16-hexadecanediol mono- or poly(2-20)alkylene (C2-C20) oxide adduct (as alkylene oxide, for example, ethylene oxide, propylene oxide, butylene oxide) di(meth)acrylate, 1, 2-Hexadecanediol poly(2-20) Alkylene (C2-C20) oxide adduct (as alkylene oxide, for example, ethylene oxide, propylene oxide, butylene oxide) di(meth)acrylate, 2-methyl-2,4-pentanediol poly(2-20) alkylene (C2- C20) Oxide adduct (eg, alkylene oxide such as ethylene oxide, propylene oxide, butylene oxide) di(meth)acrylate, 3-methyl-1,5-pentanediol poly(2-20)alkylene(C2-C20) oxide adduct (As the alkylene oxide, for example, ethylene oxide, propylene oxide, butylene oxide) di(meth)acrylate, 2-methyl-2-propyl-1,3-propanediol poly(2-20)alkylene (C2-C20) oxide adduct (Examples of alkylene oxides include ethylene oxide, propylene oxide, butylene oxide)di(meth)acrylate, 2,4-dimethyl-2,4-pentanediol poly(2-20)alkylene (C2-C20) oxide adduct (alkylene Examples of the oxide include ethylene oxide, propylene oxide, butylene oxide)di(meth)acrylate, 2,2-diethyl-1,3-propanediol mono- or poly(2-20)alkylene (C2-C20) oxide adduct ( As the alkylene oxide, for example, ethylene oxide, propylene oxide, butylene oxide)di(meth)acrylate, 2,2,4-trimethyl-1,3-pentanediol mono- or poly(2-20)alkylene (C2-C20) oxide addition Body (as alkylene oxide, for example, ethylene oxide, propylene oxide, butylene oxide) di(meth)acrylate, dimethylol octane poly(2-20) alkylene (C2-C20) oxide adduct (as alkylene oxide, for example, ethylene oxide, propylene oxide) , Butylene oxide) di(meth)acrylate, 2-ethyl-1,3-hexanediol poly(2-20) alkylene(C2-C20) oxide adduct (as alkylene oxide, for example, ethylene oxide, propylene oxide, butylene oxide) Di(meth)acrylate, 2,5-dimethyl-2,5-hexanediol poly(2-20)alkylene( C2 to C20) oxide adduct (eg, alkylene oxide such as ethylene oxide, propylene oxide, butylene oxide) di(meth)acrylate, 2-methyl-1,8-octanediol poly(2 to 20)alkylene (C2 to C20) oxide Adduct (as alkylene oxide, for example, ethylene oxide, propylene oxide, butylene oxide) di(meth)acrylate, 2-butyl-2-ethyl-1,3-propanediol poly(2-20)alkylene (C2-C20) oxide Adduct (eg, alkylene oxide such as ethylene oxide, propylene oxide, butylene oxide) di(meth)acrylate, 2,4-diethyl-1,5-pentanediol poly(2-20) alkylene (C2~C20) oxide adduct ( As the alkylene oxide, for example, ethylene oxide, propylene oxide, butylene oxide)di(meth)acrylate, and as the modified acrylate of bilphenol, bisphenol A tetraethylene oxide adduct di(meth)acrylate, bisphenol F tetraethylene oxide adduct di (Meth)acrylate, bisphenol S tetraethylene oxide adduct di(meth)acrylate, water-added bisphenol A tetraethylene oxide adduct di(meth)acrylate, water-added bisphenol F tetraethylene oxide adduct di(meth)acrylate, water-added Bisphenol A di(meth)acrylate, water-added bisphenol F di(meth)acrylate, bisphenol A tetraethylene oxide adduct dicaprolactonate di(meth)acrylate, bisphenol F tetraethylene oxide adduct dicaprolactonate di(meth) Acrylate is exemplified.

Glycerin poly(2-20) alkylene(C2-C20) oxide adduct as trifunctional modified acrylate (as alkylene oxide, for example, ethylene oxide, propylene oxide, butylene oxide) tri(meth)acrylate, trimethylolpropane poly(2-20) )Alkylene (C2-C20) oxide adduct (as alkylene oxide, for example, ethylene oxide, propylene oxide, butylene oxide) tri(meth)acrylate, trimethylolethane poly(2-20)alkylene (C2-C20) oxide adduct (alkylene) Examples of the oxide include ethylene oxide, propylene oxide, butylene oxide)tri(meth)acrylate, trimethylolhexane poly(2-20)alkylene (C2 to C20) oxide adduct (as the alkylene oxide, for example, ethylene oxide, propylene oxide, butylene). Oxide) tri(meth)acrylate, trimethylol octane poly(2-20) alkylene (C2-C20) oxide adduct (as alkylene oxide, for example, ethylene oxide, propylene oxide, butylene oxide) tri(meth)acrylate, trimethylol octane Poly(3 to 20) alkylene (C2 to C20) oxide adduct (as alkylene oxide, for example, ethylene oxide, propylene oxide, butylene oxide) tri(meth)acrylate, pentaerythritol poly(2 to 20) alkylene (C2 to C20) Oxide adducts (for example, ethylene oxide, propylene oxide, butylene oxide as alkylene oxide) tri(meth)acrylate and the like are exemplified.

A pentaerythritol poly(2-20) alkylene(C2-C20) oxide adduct (eg, ethylene oxide, propylene oxide, butylene oxide) tetra(meth)acrylate, a ditrimethylolpropane poly(2 To 20) alkylene (C2 to C20) oxide adduct (eg, alkylene oxide such as ethylene oxide, propylene oxide, butylene oxide) tetra(meth)acrylate, ditrimethylolpropane poly(2-20) alkylene oxide (eg, ethylene oxide, propylene oxide) , Butylene oxide, etc.) tetra(meth)acrylate, ditrimethylolpropane tetracaprolactonate, tetra(meth)acrylate, ditrimethylolethane poly(2-20)alkylene (C2-C20) oxide adduct (for example, ethylene oxide as alkylene oxide) Oxide, propylene oxide, butylene oxide) tetra(meth)acrylate, ditrimethylolethane poly(2-20) alkylene oxide (eg ethylene oxide, propylene oxide, butylene oxide, etc.) tetra(meth)acrylate, ditrimethylol butane poly(2... 20) Alkylene oxide (eg ethylene oxide, propylene oxide, butylene oxide, etc.) tetra(meth)acrylate, ditrimethylolhexane poly(2-20) alkylene (C2-C20) oxide adduct (eg, as alkylene oxide, ethylene oxide, propylene oxide) , Butylene oxide) tetra(meth)acrylate, ditrimethylolhexane poly(2-20) alkylene oxide (eg ethylene oxide, propylene oxide, butylene oxide, etc.) tetra(meth)acrylate, ditrimethylol octane (2-20) alkylene (C2 To C20) oxide adduct (eg, alkylene oxide such as ethylene oxide, propylene oxide, butylene oxide) tetra(meth)acrylate, ditrimethylol octane poly(4-200) alkylene oxide (eg, ethylene oxide, propylene oxide, butylene oxide, etc.) tetra (Meth)acrylate, dipentaerythritol poly(5-20) alkylene(C2-C20) oxy Side adducts (eg, alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide) penta(meth)acrylate, dipentaerythritol poly(2-20) alkylene (C2 to C20) oxide adducts (eg, alkylene oxides such as ethylene oxide, propylene) Oxide, butylene oxide) hexa(meth)acrylate, propylene oxide, butylene oxide, etc.) hexa(meth)acrylate, dipentaerythritol hexacaprolactonate poly(2-20) alkylene(C2-C20) oxide adduct (alkylene oxide) For example, ethylene oxide, propylene oxide, butylene oxide)hexa(meth)acrylate, tripentaerythritol poly(2-20)alkylene (C2~C20) oxide adduct (for example, ethylene oxide, propylene oxide, butylene oxide) hepta (Meth)acrylate, tripentaerythritol poly(2-20) alkylene (C2-C20) oxide adduct (eg alkylene oxide such as ethylene oxide, propylene oxide, butylene oxide) octa(meth)acrylate, tripentaerythritol poly(2... 20) Alkylene (C2 to C20) oxide adduct (eg, alkylene oxide such as ethylene oxide, propylene oxide, butylene oxide) hexa(meth)acrylate, tripentaerythritol polyalkylene oxide hepta(meth)acrylate, tripentaerythritol poly(2 to 20) Alkylene (C2-C20) oxide adducts (Examples of alkylene oxides include ethylene oxide, propylene oxide, butylene oxide) octa(meth)acrylate, but the present invention is not limited thereto.

Further, as a compound containing a (meth)acrylate group, an active energy ray-curable (meth)acrylic oligomer, urethane (meth)acrylate, epoxy (meth)acrylate, polyester (meth)acrylate can be appropriately used.

Examples of oligomers include polyols, esterified products of polybasic acid and (meth)acrylic acid, and epoxy acrylate. As the polyol, ethylene glycol, glycerin, trimethylolpropane, pentaerythritol, etc., and as the polybasic acid, phthalic anhydride, isophthalic acid, (anhydrous) succinic acid, (anhydrous) maleic acid, adipic acid, sebacic acid, etc. are used. It The ester reaction of the polyol, polybasic acid and (meth)acrylic acid is carried out by a conventional method.

As the urethane (meth)acrylate, general aromatic or aliphatic urethane (meth)acrylate can be mentioned. As an example, there may be mentioned (meth)acrylates such as tolylene diisocyanate, hexamethylene diisocyanate and isophorone diisocyanate.

Examples of the epoxy (meth)acrylate include general aromatic or aliphatic epoxy (meth)acrylate. Examples thereof include (meth)acrylates such as bisphenol A epoxy, bisphenol F epoxy, novolac epoxy, and phosphoric acid type epoxy.

Examples of polyester (meth)acrylates include general polyester (meth)acrylates, fatty acid-modified types, chlorinated polyesters, and the like.

As the monomer having a radical-polymerizable double bond in the active energy ray-curable composition of the present invention, a bifunctional acrylate, a trifunctional acrylate, a tetrafunctional or higher acrylate, and a trifunctional modified acrylate are preferable.

The active energy ray-curable composition of the present invention may contain a polymerization initiator. In the present invention, the polymerization initiator can be used without limitation. It is particularly preferable to contain a photopolymerization initiator.
The amount of the polymerization initiator compounded in the active energy ray-curable composition in the present invention is 0.1 to 15 parts by weight, based on 100 parts by weight of the total of the styrene-acrylate copolymer and the monomer having a radical-polymerizable double bond. It is preferably in the range of 0.5 part by weight, more preferably in the range of 0.5 to 10 parts by weight.

Examples of the photopolymerization initiator include, but are not limited to, benzophenones such as benzyl, benzophenone, p-methylbenzophenone, Michler's ketone, methylbenzophenone, 4,4′-dichlorobenzophenone, 4,4′-bisdiethylaminobenzophenone, acetophenone. , 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 1-hydroxy-cyclohexyl-phenylketone, 2-methyl-1-[4-(methylthio )Phenyl]-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, N,N-dimethylaminoacetophenone and other acetophenones, 2 ,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, 2,4-diisopropylthioxanthone and other thioxanthones, anthraquinone, chloroanthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone , 1-chloroanthraquinone, 2-amylanthraquinone, 2-aminoanthraquinone and other anthraquinones, acetophenone dimethyl ketal, benzyl dimethyl ketal and other ketals, 1.2-octanedione, 1-[4-(phenylthio)-2,2 -(O-benzoyloxime)], ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(0-acetyloxime) and other oxime esters Acylphosphines such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, phenyldisulfide 2-nitrofluorene, butyroin, anisoinethyl ether , Azobisisobutyronitrile, and the like. Among them, acetophenones, alkylphenones, acylphosphine oxides, oxyphenyls and oxime ester benzoins are preferable, and acetophenones and alkylphenones are more preferable. These photopolymerization initiators may be used alone or in combination of two or more kinds. Further, it is possible to use a photopolymerization initiator and a sensitizer together.

Sensitizers include 2,4,6-trimethylbenzophenone, 2,3,4-trimethylbenzophenone, 4-phenylbenzophenone, 3,3'-dimethyl-4-methoxybenzophenone, 4-(1,3-acryloyl- 1,4,7,10,13-pentaoxotridecyl)benzophenone, methyl-o-benzoylbenzoate, [4-(methylphenylthio)phenyl]phenylmethanone, (4-benzoylbenzyl)trimethylammonium chloride, 2- Hydroxy-2-methyl-1-phenylpropan-1-one, 1-(4-isopropylphenyl)2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxy-cyclohexyl-phenylketone, 2 -Hydroxy-2-methyl-1-styrylpropan-1-one polymer, diethoxyacetophenone, dibutoxyacetophenone, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoin normal butyl ether and the like can be mentioned. These may be used alone or in combination of two or more.

Examples of the active energy ray used for curing the active energy ray-curable composition of the present invention include ultraviolet rays, electron rays, α rays, β rays, γ rays, X rays, and other polymerizable components in the composition. (For example, it is not particularly limited as long as it can provide energy necessary for proceeding the polymerization reaction of the monomer having a radical-polymerizable double bond. Especially, when a high-energy light source is used, a polymerization initiator is used. The polymerization reaction can proceed even without the use of H. In addition, in the case of UV irradiation, mercury-free is strongly desired from the viewpoint of environmental protection, and replacement with a GaN-based semiconductor UV light-emitting device is industrial and environmental. Further, the ultraviolet light emitting diode (UV-LED) and the ultraviolet laser diode (UV-LD) are preferable as an ultraviolet light source because of their small size, long life, high efficiency and low cost.

The active energy ray-curable composition of the present invention contains various additives, for example, stabilizers (for example, polymerization inhibitors such as hydroquinone, metoquinone, and methylhydroquinone), and pigments such as inorganic pigments and organic pigments. Can be shown. Examples of inorganic pigments include yellow lead, zinc yellow, navy blue, barium sulfate, cadmium red, titanium oxide, zinc white, rouge, alumina white, calcium carbonate, ultramarine blue, carbon black, graphite, aluminum powder, and red iron oxide. Is a soluble azo pigment such as β-naphthol-based, β-oxynaphthoic acid-based, β-oxynaphthoic acid-based anilide-based, acetoacetic anilide-based, pyrazolone-based, β-naphthol-based, β-oxynaphthoic acid-based anilide-based, Insoluble azo pigments such as acetoacetic anilide monoazo, acetoacetic anilide disazo, and pyrazolone, phthalocyanine pigments such as copper phthalocyanine blue, halogenated (chlorine or brominated) copper phthalocyanine blue, sulfonated copper phthalocyanine blue, and metal-free phthalocyanine , Quinacridone, dioxazine, slene (pyrantron, anthanthrone, indanthrone, anthrapyrimidine, flavantron, thioindigo, anthraquinone, perinone, perylene, etc.), isoindolinone, metal complex, quinophthalone, etc. Various publicly known and commonly used pigments such as polycyclic pigments and heterocyclic pigments, and various additives such as fillers and viscosity modifiers may be contained depending on the purpose.

Further, as additives for imparting abrasion resistance, anti-blocking property, sliding property, and anti-scratch property, natural waxes such as carnauba wax, wood wax, lanolin, montan wax, paraffin wax, microcrystalline wax, and Fischer-Tropsch wax. Examples thereof include polyethylene wax, polypropylene wax, polytetrafluoroethylene wax, polyamide wax, and synthetic wax such as silicone compound.

In addition, additives such as ultraviolet absorbers, infrared absorbers, antibacterial agents, etc. can be added depending on the required performance.

Next, the usage form of the active energy ray-curable composition in the present invention will be described.

In the active energy ray-curable composition of the present invention, a pigment which is a colorant is not contained, and a transparent constitution results in an overprint varnish. When the pigment shown above is contained, a color printing ink is formed. Becomes

In the active energy ray-curable composition of the present invention, a binder resin other than the styrene-acrylate copolymer can be used if necessary.

As the binder resin other than the styrene-acrylate copolymer, diallyl phthalate resin, polyester, polyvinyl chloride, poly(meth)acrylic acid ester, epoxy resin, polyurethane resin, petroleum (based) resin, cellulose derivative (eg, ethyl cellulose, Cellulose acetate, nitrocellulose), vinyl chloride/vinyl acetate copolymers, polyamide resins, polyvinyl acetal resins, synthetic rubbers such as butadiene-acrylonitrile copolymers. These resins may be used alone or in combination of two or more.

The method for producing the active energy ray-curable composition of the present invention may be carried out in the same manner as in the conventional active energy ray-curable composition. For example, the styrene-acrylate copolymer of the present invention can be used at room temperature to 100°C. Polymer, if necessary, a monomer having a radical-polymerizable double bond, a composition component such as a polymerization initiator and a sensitizer, and other additives, a kneader, a triple roll, an attritor, a sand mill, a gate mixer, etc. Manufactured using the above-mentioned kneaded meat, mixing and adjusting machine.

Examples of the printing method using the active energy ray-curable composition of the present invention include lithographic printing (normal lithographic printing using dampening water and waterless lithographic printing not using dampening water), letterpress printing, intaglio printing, Examples include stencil printing, preferably lithographic printing.

The base material for the printed matter is not particularly limited, and examples thereof include printing on various materials such as paper, plastics, stickers, labels and metals, and printing on paper is preferable.

Hereinafter, the present invention will be described in more detail by way of examples, but the following examples do not limit the scope of rights of the present invention. In addition, in this invention, "part" represents a "weight part" and "%" represents the "weight%."

Method for measuring weight average molecular weight (Mw), number average molecular weight (Mn), and molecular weight distribution (Mw/Mn) of styrene-acrylate copolymer Weight average molecular weight (Mw), number average molecular weight (Mn ) of styrene-acrylate copolymer ) And the molecular weight distribution (Mw/Mn) were measured using GPC. Mw and Mn are values of standard polystyrene equivalent weight average molecular weight and number average molecular weight.
Column: Shodex LF-804 x 2 connected in series Flow rate: 1.0 mL/min
Temperature: 40°C
Detector: RID-20A
Sample: A sample for measurement was prepared by dissolving 20 mg of a sample in 10 mL of tetrahydrofuran.

Iodine value measurement The iodine value of the styrene-acrylate copolymer used for production was measured according to the method specified in JIS K6235.

(Synthesis Example 1) Styrene-acrylate copolymer (Copolymer 1)
130 g of mesitylene was added into a four-necked flask equipped with a stirrer, a reflux condenser, a thermometer, and a dropping funnel, and heated to 160°C while stirring. A mixture of 16 g of styrene, 12 g of benzyl acrylate, 14 g of 2-ethylhexyl acrylate, 22 g of trimethylolpropane triacrylate and 5 g of perbutyl Z (tert-butyl peroxybenzoate) was added dropwise to the reaction vessel over 6 hours. Then, the styrene-acrylate copolymer was polymerized for 30 minutes and then cooled to room temperature. The unreacted monomer was removed by treating the obtained polymerization liquid with 10 times the amount of hexane, and dried under reduced pressure at 80° C. to obtain a copolymer 1. (Yield: 60%, weight average molecular weight: 27,000, number average molecular weight: 5,500, molecular weight distribution: 4.9, iodine value: 10)

(Synthesis Example 2) Styrene-acrylate copolymer (Copolymer 2)
130 g of mesitylene was added into a four-necked flask equipped with a stirrer, a reflux condenser, a thermometer, and a dropping funnel, and heated to 160°C while stirring. A mixture of 16 g of styrene, 13 g of benzyl acrylate, 15 g of 2-ethylhexyl acrylate, 18 g of 1,6-hexanediol diacrylate and 5 g of perbutyl Z (tert-butyl peroxybenzoate) was added dropwise to the reaction vessel over 6 hours. Then, the styrene-acrylate copolymer was polymerized for 30 minutes and then cooled to room temperature. Unreacted monomer was removed by treating the obtained polymerization liquid with 10 times the amount of hexane, and dried under reduced pressure at 80° C. to obtain a copolymer 2. (Yield: 60%, weight average molecular weight: 29,000, number average molecular weight: 11,000, molecular weight distribution: 2.6, iodine value: 5)

(Example)
The active energy ray-curable compositions having the respective compositions shown in the table below were prepared, and the respective properties were evaluated.

(Example 1, Comparative Example 1)
1) Evaluation of solubility of active energy ray-curable composition Table 1 shows the copolymers 1 and 2 obtained in Synthesis Example 1 and Synthesis Example 2, a monomer having a radical-polymerizable double bond, and a polymerization inhibitor. Each composition amount described was added, and heated and mixed at 90° C. for 2 hours to prepare an active energy ray-curable composition. After cooling each composition to room temperature (25° C.), it was allowed to stand overnight, and the solubility was confirmed by its transparent appearance. Those that had a transparent appearance even after cooling were evaluated as ◯, and those that became cloudy: as ×. The results of Example 1 are shown in Table 1. The results of Comparative Example 1 are shown in Table 2.

表１に示した共重合体１以外の成分は下記のとおりである。
また、表１に示す組成量は重量部での表記である。
※１：ＤＴＭＰＴＡ：ＭＩＷＯＮ製　ＭＩＲＡＭＥＲ Ｍ４１０　ジトリメチロールプロパンテトラアクリレート
※２：３ＰＯ-ＴＭＰＴＡ：サートマー株式会社製　ＳＲ４９２ＴＦＮ　プロピレンオキサイド変性トリメチロールプロパントリアクリレート
※３：ＴＰＧＤＡ ：サートマー株式会社製　ＳＲ３０６Ｈ　トリプロピレングリコールジアクリレート
※４：ＴＭＰＴＡ：ＭＩＷＯＮ製　ＭＩＲＡＭＥＲ Ｍ３００　トリメチロールプロパントリアクリレート
※５：３ＥＯ-ＴＭＰＴＡ：ＭＩＷＯＮ製　ＭＩＲＡＭＥＲ　Ｍ３１３０　エチレンオキサイド変性トリメチロールプロパントリアクリレート
※６：メチルハイドロキノン：和光純薬株式会社製

The components other than the copolymer 1 shown in Table 1 are as follows.
Further, the composition amounts shown in Table 1 are expressed in parts by weight.
*1: DTMPTA: MIWON MIRAMER M410 ditrimethylolpropane tetraacrylate *2: 3PO-TMPTA: Sartomer Co., Ltd. SR492TFN propylene oxide modified trimethylolpropane triacrylate *3: TPGDA: Sartomer Co., Ltd. SR306H tripropylene glycol diacrylate * 4: TMPTA: manufactured by MIWON MIRAMER M300 trimethylolpropane triacrylate *5: 3EO-TMPTA: manufactured by MIWON MIRAMER M3130 ethylene oxide-modified trimethylolpropane triacrylate *6: methylhydroquinone: manufactured by Wako Pure Chemical Industries, Ltd.

表２に示した共重合体２以外の成分は表１と同じである。また、表２に示す組成量は重量部での表記である。

The components other than the copolymer 2 shown in Table 2 are the same as those in Table 1. Further, the composition amounts shown in Table 2 are expressed in parts by weight.

From the results of Tables 1 and 2, it was shown that the styrene-acrylate copolymer of the present invention is suitably dissolved in compounds having various acrylate groups.

(Example 2 and Comparative Example 2)
1) Dryability test An active energy ray-curable composition prepared from each component listed in Table 3 was coated on a piece of art paper (art paper manufactured by Oji Paper Co., Ltd.) using an RI tester, and the output was 80 W/cm. It was cured with a metal halide lamp (lamp distance 11 cm, conveyor speed 100 m/min). As the UV curing device, a conveyor type ultraviolet curing device manufactured by Eye Graphics Co., Ltd. was used. The coating film was touched with a finger and passed multiple times until no fingerprints were left on the surface (tack free). When the coating film was touched with a finger after UV irradiation was performed 5 times, the surface was not fingerprinted: ◯, the surface was fingerprinted: x. The evaluation results are shown in Table 3.

2) Scratch property The active energy ray-curable composition prepared from the components shown in Table 3 was coated on one-sided art paper and cured in the same manner as in the drying test. The surface state of the obtained coating film was confirmed by rubbing the surface with a nail. The coating film was evaluated as follows: no change or abrasion while resisting: o, easy abrasion: x. The evaluation results are shown in Table 3.

3) Adhesion test An active energy ray-curable composition prepared from the components shown in Table 3 was coated on one-sided art paper and cured in the same manner as in the drying test. When the Nichiban 18 mm wide cellophane tape (product number: LP-18) was attached to the obtained coating film and separated, the coating film remained on the art paper without peeling: ○, the coating peeled: × Evaluated as. The evaluation results are shown in Table 3.

表３に示した共重合体１及び２以外の成分は下記のとおりである。
表３に示す組成量は重量部での表記である。
※１：ＤＴＭＰＴＡ：ＭＩＷＯＮ製　ＭＩＲＡＭＥＲ Ｍ４１０　ジトリメチロールプロパンテトラアクリレート
※２：Ｏｍｎｉｒａｄ９０７：ＩＧＭ　Ｒｅｓｉｎｓ Ｂ．Ｖ．製　２－メチル－１－[４－(メチルチオ)フェニル]－２－モルフォリノプロパン－１－オン

The components other than the copolymers 1 and 2 shown in Table 3 are as follows.
The composition amounts shown in Table 3 are expressed in parts by weight.
*1: DTMPTA: MIRAMER M410 ditrimethylolpropane tetraacrylate manufactured by MIWON *2: Omnirad907: IGM Resins B.M. V. 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one

As shown in Table 3, the active energy ray-curable composition containing the styrene-acrylate copolymer of the present invention was shown to have excellent drying property, scratch property and adhesiveness.

(Example 3)
Evaluation of physical properties when using an active energy ray-curable composition as an ink 30 parts by weight of the copolymer 1 produced in Synthesis Example 1, 70 parts by weight of DTMPTA, and 0.1 parts by weight of methylhydroquinone were mixed to obtain an active energy. A line-curable composition was prepared. Furthermore, an ink was prepared with the compounding amounts of the respective components shown in Table 4. Various physical properties of the obtained ink were acquired by the evaluation methods described below.

1) Drying test The prepared ink was coated on a piece of art paper (art paper manufactured by Oji Paper Co., Ltd.) using an RI tester and cured with a metal halide lamp (lamp distance 11 cm, conveyor speed 100 m/min) with an output of 80 W/cm. Let As the UV curing device, a conveyor type ultraviolet curing device manufactured by Eye Graphics Co., Ltd. was used. The coating film was touched with a finger and passed multiple times until no fingerprints were left on the surface (tack free). When the coating film was touched with a finger after UV irradiation was performed 5 times, the surface was not fingerprinted: ◯, the surface was fingerprinted: x. The evaluation results are shown in Table 4.

2) Scratch property The prepared ink was coated on one-sided art paper and cured in the same manner as in the drying test. The surface state of the obtained coating film was confirmed by rubbing the surface with a nail. The coating film was evaluated as follows: no change or abrasion while resisting: o, easy abrasion: x. The evaluation results are shown in Table 4.

3) Adhesion test The prepared ink was coated on one-sided art paper and cured in the same manner as in the drying test. When the Nichiban 18 mm wide cellophane tape (product number: LP-18) was attached to the obtained coating film and separated, the coating film remained on the art paper without peeling: ○, the coating peeled: × Evaluated as. The evaluation results are shown in Table 4.

4) Static fluidity The ink was dripped on the inclined plate inclined at 60 degrees, and after 10 minutes, the flow distance was confirmed. The results are shown in Table 4.

※１：トーヨーカラー株式会社製　リオノールブルーＦＧ－７３３０
※２：東亞合成株式会社製　アロニックス　Ｍ－４０４
※３：ＭＩＷＯＮ製　ＭＩＲＡＭＥＲ Ｍ３１３０
※４：Ｓｈａｍｒｏｃｋ製　Ｓ－３９４－Ｎ１
※５：ＩＧＭ　Ｒｅｓｉｎｓ Ｂ．Ｖ．製　２－ベンジル－２－ジメチルアミノ－１－（４－モルフォリノフェニル）－ブタノン－１

*1: Lionol Blue FG-7330 manufactured by Toyo Color Co., Ltd.
*2: Aronix M-404 manufactured by Toagosei Co., Ltd.
*3: MIWON MIRAMER M3130
*4: Shamrock S-394-N1
*5: IGM Resins B. V. 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1

As shown in Table 4, when the active energy ray-curable composition containing the styrene-acrylate copolymer of the present invention is used as an ink, it has excellent physical properties required for the ink. It was

The active energy ray-curable composition containing the styrene-acrylate copolymer of the present invention has excellent adhesion to a substrate such as paper, and when used as an ink, the curability and the adhesion are excellent. Since it is excellent in physical properties such as scratch resistance, it is useful for various printing inks, paints, coating agents, photoresists and the like.

Claims (11)

A styrene-acrylate copolymer,
The ratio of the structural unit (A) derived from the styrene compound is 10 to 90 mol %,
The ratio of the structural unit (B) derived from the acrylate compound is 10 to 90 mol %,
The constitutional unit (B) derived from the acrylate compound is characterized by containing the constitutional unit (b-1) derived from a compound having at least three or more acryloyl groups in the molecule. The styrene-acrylate copolymer according to claim 1, wherein the compound having at least three acryloyl groups in the molecule is an acrylate compound having three acryloyl groups or an acrylate compound having four acryloyl groups. The compound having at least three or more acryloyl groups in the molecule is trimethylolpropane tri(meth)acrylate, trimethyloloctanetri(meth)acrylate, trimethylolpropane polyethoxytri(meth)acrylate, trimethylolpropane polypropoxytril. (Meth)acrylate, trimethylolpropane polyethoxypolypropoxytri(meth)acrylate, tris[(meth)acryloyloxyethyl]isocyanurate, pentaerythritol tri(meth)acrylate, pentaerythritol polyethoxytetra(meth)acrylate, pentaerythritol The styrene according to claim 1 or 2, which is one selected from polypropoxytetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate and dipentaerythritol tetra(meth)acrylate. -Acrylate copolymer. The structural unit (B) derived from an acrylate compound further contains a structural unit (b-2) derived from an aromatic acrylate compound and a structural unit (b-3) derived from an aliphatic acrylate compound. The styrene-acrylate copolymer according to any one of 3 above. The styrene-acrylate copolymer according to any one of claims 1 to 4, wherein the styrene-acrylate copolymer has a molecular weight distribution (weight average molecular weight (Mw)/number average molecular weight (Mn)) of 1 to 50. The styrene-acrylate copolymer according to any one of claims 1 to 5, wherein the styrene-acrylate copolymer has an iodine value of 1 to 100. An active energy ray-curable composition comprising the styrene-acrylate copolymer according to any one of claims 1 to 6. The active energy ray-curable composition according to claim 7, further comprising a monomer having a radical-polymerizable double bond. An ink comprising the composition according to claim 7 or 8. A paint comprising the composition according to claim 7. The paint according to claim 11, which is an overprint varnish.