JP2018172672A - Active energy ray-curable resin composition, and coating agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an active energy ray-curable resin composition which can form a coating film being hardly curled due to having small curing contraction when forming a curing coating film, and excellent in bendability, and can form a tack-free coating film surface even when applying a load after coating on a base material and drying, and to provide a coating agent using the same.SOLUTION: An active energy ray-curable resin composition comprises an urethane (meta)acrylate-based composition [I] which is prepared by reacting (meta)acrylate (a1)-(a3) in a mixture (A) of (meta)acrylate (a1)-(a4) as follows, as a reactant of pentaerythritol and (meta)acrylic acid with polyvalent isocyanate (B). In the urethane (meta)acrylate-based composition [I], a hydroxyl value of the mixture (A) is 200 mgKOH/g or more: (a1), pentaerythritol mono (meta)acrylate; (a2), pentaerythritol di(meta)acrylate; (a3), pentaerythritol tri(meta)acrylate; and (a4), pentaerythritol tetra(meta)acrylate.SELECTED DRAWING: None

Description

  The present invention relates to an active energy ray-curable resin composition containing a urethane (meth) acrylate-based composition and a coating agent, and more particularly, since curling shrinkage is small when a cured coating film is formed. It is difficult to form a coating film with excellent hardness and flexibility, and furthermore, it is not sticky in an uncured state even when a load is applied after coating on a substrate and drying, that is, a tack-free coating surface. The present invention relates to an active energy ray-curable resin composition that can be formed and a coating agent using the same.

  Conventionally, active energy ray-curable resin compositions are cured by irradiation with active energy rays such as radiation and ultraviolet rays for a very short time. Widely used, urethane (meth) acrylate compounds and polyfunctional monomers are used as the curing component. However, when the active energy ray-curable resin composition is used as a coating agent, particularly as a coating agent for a hard coat, there is a problem that the shrinkage of the coating film occurs and the cured coating film tends to curl. Difficult things are needed.

  In addition, since the coating agent for hard coat is also used as a protective film in bent parts of molded products, displays, etc., it is required to be flexible so that cracks do not easily occur even when a plastic film with a cured coating film is bent. Yes.

  Regarding the above-mentioned difficulty in curling, a curable resin composition in which inorganic fine particles are added to a curable resin (for example, refer to Patent Document 1) or a high molecular weight urethane as a curing component in order to suppress curing shrinkage. A curable resin composition containing (meth) acrylate (see, for example, Patent Document 2), a hydroxyl group in a (meth) acrylic acid adduct of pentaerythritol having a hydroxyl value of 130 mgKOH / g or more, A curable resin composition containing urethane (meth) acrylate obtained by reacting an isocyanate group of a polyvalent isocyanate compound (for example, see Patent Document 3) has been proposed.

  Further, as a method for increasing the hardness of the hard coat layer in order to improve the scratch resistance, for example, a resin composition containing dipentaerythritol hexaacrylate and tripentaerythritol octaacrylate is used as a triacetyl having a thickness of 80 μm. A technique is known in which a film obtained by applying a film of 12 μm on a cellulose film and curing it exhibits a hardness of about 5H pencil hardness (see, for example, Patent Document 4).

  Furthermore, in order to improve the scratch resistance, curl resistance, flexibility, and impact resistance of the cured coating film, a urethane (meth) acrylate resin using a polyisocyanate compound and a dihydroxydi (meth) acrylate compound as a reaction raw material ( For example, see Patent Document 5).

JP 2010-77292 A JP 2010-180319 A JP 2012-229412 A JP 2009-286924 A International Publication No. 2016/194765

  However, the disclosed technique of Patent Document 1 has a problem that the organic solvent that can be used is limited in consideration of the compatibility between the inorganic fine particles and the curable resin, and the possibility that the surface abnormality of the coating film increases. Furthermore, since inorganic fine particles are generally expensive, resins and paints containing them are also expensive, and practically, the use of the curable resin is limited to special applications.

  In the technique disclosed in Patent Document 2, since the production method for increasing the molecular weight of urethane (meth) acrylate used as a curing component is a multistage reaction, the operation becomes complicated and the scratch resistance of the coating film decreases. It was something to end up with.

  With the disclosed technology of Patent Document 3, a cured coating film having a small curing shrinkage and curling can be obtained, but when the coating film is hardened and greatly bent by a tetraacrylate monomer contained in a large amount in the raw material, Cracks would occur.

  In the disclosed technique of Patent Document 4, although the surface hardness of the cured coating film is high, the curl generated at the time of curing is large, and since it is hard and brittle, cracking occurs when the coating film is bent. It was.

  In the disclosed technology of Patent Document 5, although the scratch resistance, curl resistance, flexibility, and impact resistance of the cured coating film are improved, the coating film in an uncured state before being applied on the base material. In, the surface of the coating film had a tendency to be sticky, that is, a tacky feeling.

  In recent years, there has been an increasing demand for a coating film formed of an active energy ray-curable resin composition that is not sticky even in an uncured state that has only been dried, that is, tack-free. For example, when multicolor printing is performed using an active energy ray-curable ink, if the printed surface is not sticky in a dry state, the printed surface is dried and printed one after another, and finally activated. There exists an advantage that it can harden | cure with an energy ray collectively. Moreover, when the active energy ray-curable resin composition is applied onto a substrate film and dried to form a coating film, it can be handled as a film roll when it is tack-free when stored and transported. Furthermore, after the uncured laminated film formed on the film is attached to the molded product with the resin composition side as the molded product side, active energy ray curing is performed to easily form various molded products. A cured film can be formed.

  However, many of the active energy ray curable resin compositions are low molecular weight acrylic ester compounds collectively referred to as oligomers, such as urethane (meth) acrylate, epoxy (meth) acrylate, polyester (meth) acrylate, (meth). Acrylic acrylate and liquid active energy ray curable monomer, collectively called reactive dilution monomer, are mixed, so the coating surface until cured is in a state where the coating surface is sticky, and further improvements Is desired.

  Therefore, in the present invention, under such a background, when a cured coating film is formed, it is difficult to curl because of a small curing shrinkage, and a coating film excellent in flexibility can be formed. An object of the present invention is to provide an active energy ray-curable resin composition capable of forming a tack-free coating surface even when a load is applied after being applied on a substrate and dried, and a coating agent using the same It is.

  However, as a result of intensive studies in view of such circumstances, the present inventors, as a result, have reacted with pentaerythritol and (meth) acrylic acid as a curing component, and have a hydroxyl value higher than that of the following (meta) By using a urethane (meth) acrylate composition obtained by reacting a (meth) acrylate having a hydroxyl group in a mixture (A) of acrylates (a1) to (a4) and a polyvalent isocyanate (B), A cured coating film that is hard to curl due to low curing shrinkage and has excellent hardness and flexibility, and is a tack-free coating film that is applied to a substrate, dried, and then cured. The inventors found that a surface was obtained and completed the present invention.

That is, the gist of the present invention is that (meth) acrylate (a1) to (meth) acrylate (a1) to (a) in a mixture (A) of the following (meth) acrylates (a1) to (a4), which is a reaction product of pentaerythritol and (meth) acrylic acid. Active energy ray curing comprising a urethane (meth) acrylate composition [I] obtained by reacting a3) with a polyvalent isocyanate (B), wherein the mixture (A) has a hydroxyl value of 200 mgKOH / g or more. The present invention relates to a conductive resin composition.
(A1) Pentaerythritol mono (meth) acrylate (a2) Pentaerythritol di (meth) acrylate (a3) Pentaerythritol tri (meth) acrylate (a4) Pentaerythritol tetra (meth) acrylate

  Moreover, in this invention, the coating agent formed by containing the said active energy ray curable resin composition is also provided.

  The active energy ray-curable resin composition of the present invention is less likely to curl due to small curing shrinkage, can form a cured coating film with excellent hardness and flexibility, and is also tack-free even before coating. The coating film surface can be formed and is useful for various applications such as a hard coating agent.

  When the content ratio of the pentaerythritol di (meth) acrylate (a2) in the mixture (A) of the (meth) acrylates (a1) to (a4) is 10 to 50% by weight, both hardness and flexibility can be achieved. To become better.

  When the content ratio of pentaerythritol di (meth) acrylate (a2) with respect to the total of (meth) acrylates (a1) to (a3) is 15 to 55% by weight, it becomes more excellent in terms of both hardness and flexibility. .

  When the weight average molecular weight of the urethane (meth) acrylate composition [I] is 1,000 to 20,000, the active energy ray-curable resin composition is easily handled.

The present invention is described in detail below.
In the present invention, (meth) acryl means acryl or methacryl, (meth) acryloyl means acryloyl or methacryloyl, and (meth) acrylate means acrylate or methacrylate.

The active energy ray-curable resin composition of the present invention is a (meth) acrylate in a mixture (A) of the following (meth) acrylates (a1) to (a4), which is a reaction product of pentaerythritol and (meth) acrylic acid. It comprises a urethane (meth) acrylate composition [I] obtained by reacting (a1) to (a3) with a polyvalent isocyanate (B).
(A1) Pentaerythritol mono (meth) acrylate (a2) Pentaerythritol di (meth) acrylate (a3) Pentaerythritol tri (meth) acrylate (a4) Pentaerythritol tetra (meth) acrylate

  The hydroxyl value of the mixture (A) of the (meth) acrylates (a1) to (a4) obtained by reacting the pentaerythritol with (meth) acrylic acid needs to be 200 mgKOH / g or more, Preferably it is 210-380 mgKOH / g, Most preferably, it is 230-320 mgKOH / g.

  If the hydroxyl value of the mixture (A) is too small, the number of ethylenically unsaturated groups is low and the content of pentaerythritol tetra (meth) acrylate that does not react with isocyanate increases, so that the curing shrinkage during curing is large. Therefore, it tends to curl easily, and further, the flexibility tends to decrease. In general, when the hydroxyl value is too large, the viscosity increases with increasing molecular weight, which tends to be difficult to handle.

  The hydroxyl value in the present invention can be determined by a method according to JIS K 0070 1992.

  Moreover, in this invention, it is hardness that the content rate of the pentaerythritol di (meth) acrylate (a2) in the mixture (A) of the said (meth) acrylate (a1)-(a4) is 10 to 50 weight%. And is preferably in terms of both flexibility and particularly preferably 15 to 45% by weight, more preferably 20 to 40% by weight. If the content is too small, the flexibility tends to decrease, and if it is too large, the hardness tends to decrease or the viscosity increases.

  Furthermore, the content ratio of pentaerythritol di (meth) acrylate (a2) with respect to the total of the (meth) acrylates (a1) to (a3) is preferably 15 to 55% by weight in terms of both hardness and flexibility, Especially preferably, it is 20 to 50 weight%, More preferably, it is 25 to 45 weight%. If the content is too small, the flexibility tends to decrease, and if it is too large, the hardness tends to decrease or the viscosity increases.

  In the present invention, pentaerythritol and (meth) acrylic acid are reacted to prepare an (meth) acrylic acid adduct of pentaerythritol, but the reaction of pentaerythritol and (meth) acrylic acid is carried out by a known general method. be able to. In this reaction, pentaerythritol mono (meth) acrylate (a1) in which one (meth) acrylic acid is added to pentaerythritol, pentaerythritol di (meth) acrylate (a2) in which two are added, and pentad in which three are added. A mixture (A) containing erythritol tri (meth) acrylate (a3) and four-added pentaerythritol tetra (meth) acrylate (a4) is obtained, and a mixture (A) having the above hydroxyl value as a whole is obtained. be able to.

  The mixture (A) may contain a side reaction product such as a Michael adduct of acrylic acid.

  In adjusting the hydroxyl value, for example, the content ratio of (meth) acrylates (a1) to (a4) can be adjusted.

  In the present invention, the polyvalent isocyanate (B) reacts with the (meth) acrylates (a1) to (a3). Specifically, for example, tolylene diisocyanate, diphenylmethane diisocyanate, polyphenylmethane polyisocyanate. , Aromatic polyisocyanates such as modified diphenylmethane diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, phenylene diisocyanate, naphthalene diisocyanate; aliphatic polyisocyanates such as hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, lysine diisocyanate, lysine triisocyanate Hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate Alicyclic polyisocyanates such as nates and norbornene diisocyanates; or trimer compounds or multimeric compounds of these polyisocyanates, allophanate type polyisocyanates, burette type polyisocyanates, water-dispersed polyisocyanates (for example “ Aquanate 105 "," Aquanate 120 "," Aquanate 210 ", etc.). These may be used alone or in combination of two or more.

  Among these, alicyclic polyisocyanates and aromatic polyisocyanates are preferable from the viewpoint of strength, and isophorone diisocyanate, hydrogenated xylylene diisocyanate, xylylene diisocyanate, and tolylene diisocyanate are particularly preferable.

  In the present invention, the urethane (meth) acrylate composition [I] includes the hydroxyl groups of (meth) acrylates (a1) to (a3) in the mixture (A) of the above (meth) acrylates (a1) to (a4). It can be obtained by reacting with the isocyanate group of the polyvalent isocyanate (B). In this case, the urethane (meth) acrylate composition [I] is obtained by reacting (meth) acrylate (a1) and polyvalent isocyanate (B), (meth) acrylate (a2) and polyvalent isocyanate (B). , (Meth) acrylate (a3) and polyisocyanate (B) are contained, and further, (meth) acrylates (a1) to (a3) are not contained in the system. The reaction product and (meth) acrylate (a4) which does not participate in the reaction are also contained.

  In the reaction of (meth) acrylates (a1) to (a3) and the polyvalent isocyanate (B), the functional group molar ratio of the hydroxyl group to the isocyanate group is adjusted, and the reaction catalyst described later is used as necessary. Can do.

  The reaction molar ratio of the charge of the polyvalent isocyanate (B) and the mixture (A) of (meth) acrylates (a1) to (a4) is, when the isocyanate group of the polyvalent isocyanate (B) is two, The polyvalent isocyanate (B) :( meth) acrylate mixture (A) is preferably from 1: 1 to 1: 5, particularly preferably from 1: 1 to 1: 3, more preferably from 1: 1 to 1: 2. It is.

  If the ratio of the mixture (A) is too large, the amount of low molecular weight monomers increases, and the shrinkage of curing increases, so that the curl tends to increase. If the ratio of the mixture (A) is too small, unreacted polyvalent isocyanate. (B) remains, and the stability and safety of the cured coating film tend to decrease.

  The reaction of (meth) acrylates (a1) to (a3) and the polyvalent isocyanate (B) in the (meth) acrylate mixture (A) is usually performed by reacting the mixture (A) and the polyvalent isocyanate (B) with a reactor. The reaction may be carried out in batch or separately.

  In the above reaction, it is also preferable to use a catalyst for the purpose of accelerating the reaction. Examples of such a catalyst include dibutyltin dilaurate, dibutyltin diacetate, trimethyltin hydroxide, tetra-n-butyltin, bisacetylacetonate. Organometallic compounds such as zinc, zirconium tris (acetylacetonate) ethylacetoacetate, zirconium tetraacetylacetonate; tin octylate, tin octenoate, zinc hexanoate, zinc octenoate, zinc stearate, zirconium 2-ethylhexanoate , Metal salts such as cobalt naphthenate, stannous chloride, stannic chloride and potassium acetate; triethylamine, triethylenediamine, benzyldiethylamine, 1,4-diazabicyclo [2,2,2] octane, 1,8-diazabicyclo [ 5, 4 0] amine catalysts such as undecene, N, N, N ′, N′-tetramethyl-1,3-butanediamine, N-methylmorpholine, N-ethylmorpholine; bismuth nitrate, bismuth bromide, bismuth iodide, In addition to bismuth sulfide, etc., organic bismuth compounds such as dibutyl bismuth dilaurate and dioctyl bismuth dilaurate, bismuth 2-ethylhexanoate, bismuth naphthenate, bismuth isodecanoate, bismuth neodecanoate, bismuth laurate, maleic acid Bismuth catalysts such as bismuth salts, bismuth stearate, bismuth oleate, bismuth linoleate, bismuth acetate, bismuth bisneodecanoate, bismuth disalicylate, bismuth digallate, etc. Among them, among them, dibutyltin di Ureto, 1,8-diazabicyclo [5,4,0] undecene is preferred. These can be used alone or in combination of two or more.

  In the above reaction, it is preferable to use a polymerization inhibitor. As said polymerization inhibitor, the publicly known general thing used as a polymerization inhibitor can be used, for example, p-benzoquinone, naphthoquinone, tolquinone, 2,5-diphenyl-p-benzoquinone, hydroquinone, 2, Quinones such as 5-di-t-butylhydroquinone, methylhydroquinone and mono-t-butylhydroquinone, aromatics such as 4-methoxyphenol and 2,6-di-t-butylcresol, pt-butylcatechol Etc. Among them, aromatics are preferable, and 4-methoxyphenol and 2,6-di-t-butylcresol are particularly preferable. These may be used alone or in combination of two or more.

  In the reaction, an organic solvent having no functional group that reacts with an isocyanate group, for example, esters such as ethyl acetate and butyl acetate, ketones such as methyl ethyl ketone and methyl isobutyl ketone, and aromatics such as toluene and xylene Organic solvents, such as a kind, can be used. These may be used alone or in combination of two or more.

  The reaction temperature is usually 30 to 90 ° C., preferably 40 to 80 ° C., and the reaction time is usually 4 to 72 hours, preferably 8 to 48 hours.

  Thus, the urethane (meth) acrylate composition [I] used in the present invention is obtained.

  The urethane (meth) acrylate composition [I] preferably has a weight average molecular weight of 1,000 to 20,000, particularly preferably 2,000 to 18,000, more preferably 3,000 to 16. , 000. If the weight average molecular weight is too small, the cured coating film tends to be brittle, and if it is too large, the viscosity tends to be high and difficult to handle.

  In addition, the said weight average molecular weight is a weight average molecular weight by standard polystyrene molecular weight conversion, a column: ACQUITY APC XT 450, one column: ACQUITY APC XT 450 on a high performance liquid chromatograph (Waters, "ACQUITY APC system"). And one ACQUITY APC XT 45, a total of four in series.

  The urethane (meth) acrylate content in the urethane (meth) acrylate composition [I] is preferably 50% by weight or more, particularly preferably 60% by weight or more, more preferably 70% by weight or more, and particularly preferably. 80% by weight or more. The upper limit is usually 95% by weight.

<Active energy ray-curable resin composition>
The active energy ray-curable resin composition of the present invention (hereinafter sometimes abbreviated as “resin composition”) contains the urethane (meth) acrylate composition [I], and such active energy. The linear curable resin composition preferably further contains a photopolymerization initiator [II]. In addition, other urethane (meth) acrylates, ethylenically unsaturated monomers other than urethane (meth) acrylate, acrylic resins, surface conditioners, leveling agents, polymerization inhibitors, etc. are added within a range not impairing the effects of the present invention. Furthermore, fillers, dyes, pigments, oils, plasticizers, waxes, desiccants, dispersants, wetting agents, gelling agents, stabilizers, antifoaming agents, surfactants, leveling agents, thixotropic properties Additives, antioxidants, flame retardants, antistatic agents, fillers, reinforcing agents, matting agents, crosslinking agents, silica, water-dispersed or solvent-dispersed silica, zirconium compounds, preservatives, etc. is there.

  Examples of the photopolymerization initiator [II] include diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzyldimethyl ketal, 4- (2-hydroxyethoxy) phenyl- (2 -Hydroxy-2-propyl) ketone, 1-hydroxycyclohexyl phenyl ketone, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy -1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] -phenyl} -2-methyl-propane, 2-methyl-2-morpholino (4-thiomethylphenyl) propane-1 -One, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone, 2-hydroxy- Acetophenones such as methyl-1- [4- (1-methylvinyl) phenyl] propanone oligomer; benzoins such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether; benzophenone, o- Methyl benzoylbenzoate, 4-phenylbenzophenone, 4-benzoyl-4'-methyl-diphenyl sulfide, 3,3 ', 4,4'-tetra (t-butylperoxycarbonyl) benzophenone, 2,4,6-trimethyl Benzophenones such as benzophenone, 4-benzoyl-N, N-dimethyl-N- [2- (1-oxo-2-propenyloxy) ethyl] benzenemethananium bromide, (4-benzoylbenzyl) trimethylammonium chloride, etc. Nons; 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone, 1-chloro-4-propoxythioxanthone, 2- (3-dimethylamino-2-hydroxy) -3 Thioxanthones such as 2,4-dimethyl-9H-thioxanthone-9-one mesochloride; 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethyl -Acylphosphine oxides such as pentylphosphine oxide and bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide; 1.2-octanedione, 1- [4- (phenylthio)-, 2- ( o-benzoyloxime)] Examples include oxime esters. In addition, only 1 type of these photoinitiators [II] may be used independently, and 2 or more types may be used together.

  Among these, benzyl dimethyl ketal, 1-hydroxycyclohexyl phenyl ketone, benzoyl isopropyl ether, 4- (2-hydroxyethoxy) -phenyl (2-hydroxy-2-propyl) ketone, 2-hydroxy-2-methyl-1- It is preferable to use phenylpropan-1-one.

  Examples of these auxiliary agents include triethanolamine, triisopropanolamine, 4,4′-dimethylaminobenzophenone (Michler ketone), 4,4′-diethylaminobenzophenone, 2-dimethylaminoethylbenzoic acid, 4-dimethylamino. Ethyl benzoate, ethyl 4-dimethylaminobenzoate (n-butoxy), isoamyl 4-dimethylaminobenzoate, 2-ethylhexyl 4-dimethylaminobenzoate, 2,4-diethylthioxanthone, 2,4-diisopropylthio It is also possible to use xanthone or the like together. These may be used alone or in combination of two or more.

  As content of photoinitiator [II], it is preferable that it is 0.1-20 weight part with respect to 100 weight part of hardening components contained in a resin composition, Most preferably, it is 0.5-10. Part by weight, more preferably 1 to 10 parts by weight. When the content of the photopolymerization initiator [II] is too small, curing tends to be poor and film formation tends to be difficult, and when it is too large, yellowing of the cured coating film tends to occur and coloring problems tend to occur.

  Examples of the ethylenically unsaturated monomer other than urethane (meth) acrylate include a monofunctional monomer, a bifunctional monomer, and a trifunctional or higher polyfunctional monomer. These may be used alone or in combination of two or more.

  Examples of such monofunctional monomers include styrene monomers such as styrene, vinyl toluene, chlorostyrene, α-methylstyrene, methyl (meth) acrylate, ethyl (meth) acrylate, acrylonitrile, 2-methoxyethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, phenoxyethyl (meth) acrylate, 2-phenoxy-2-hydroxypropyl (meth) acrylate, 2-hydroxy -3-phenoxypropyl (meth) acrylate, 3-chloro-2-hydroxypropyl (meth) acrylate, glycerin mono (meth) acrylate, glycidyl (meth) acrylate, lauryl (meth) acrylate Rate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, tricyclodecanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, dicyclopentanyl (meth) acrylate (2-methyl-2-ethyl-1,3-dioxolan-4-yl) -methyl (meth) acrylate, cyclohexanespiro-2- (1,3-dioxolan-4-yl) -methyl (meth) acrylate, 3-ethyl-3-oxetanylmethyl (meth) acrylate, γ-butyrolactone (meth) acrylate, n-butyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) Acu Rate, decyl (meth) acrylate, isodecyl (meth) acrylate, dodecyl (meth) acrylate, n-stearyl (meth) acrylate, benzyl (meth) acrylate, phenol ethylene oxide modified (n = 2) (meth) acrylate, nonylphenol propylene Half (meth) acrylates of phthalic acid derivatives such as oxide-modified (n = 2.5) (meth) acrylate, 2- (meth) acryloyloxyethyl acid phosphate, 2- (meth) acryloyloxy-2-hydroxypropyl phthalate, Furfuryl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, carbitol (meth) acrylate, benzyl (meth) acrylate, butoxyethyl (meth) acrylate, allyl (meth) (Meth) acrylate monomers such as acrylate, (meth) acryloylmorpholine, polyoxyethylene secondary alkyl ether acrylate, 2-hydroxyethylacrylamide, N-methylol (meth) acrylamide, N-vinylpyrrolidone, 2-vinylpyridine And vinyl acetate.

  Examples of such bifunctional monomers include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, and di Propylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, butylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, ethylene oxide modified bisphenol A type di (meth) acrylate, propylene oxide modified bisphenol A Type di (meth) acrylate, cyclohexanedimethanol di (meth) acrylate, ethoxylated cyclohexanedimethanol di (me ) Acrylate, dimethylol dicyclopentane di (meth) acrylate, tricyclodecane dimethanol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, glycerin di (meth) acrylate, pentaerythritol di (meth) Acrylate, ethylene glycol diglycidyl ether di (meth) acrylate, diethylene glycol diglycidyl ether di (meth) acrylate, diglycidyl phthalate di (meth) acrylate, hydroxypivalic acid modified neopentyl glycol di (meth) acrylate, ethylene isocyanurate Examples thereof include oxide-modified diacrylate.

  Examples of the tri- or higher functional monomer include trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa ( (Meth) acrylate, tri (meth) acryloyloxyethoxytrimethylolpropane, glycerin polyglycidyl ether poly (meth) acrylate, isocyanuric acid ethylene oxide modified triacrylate, caprolactone modified dipentaerythritol penta (meth) acrylate, caprolactone modified dipentaerythritol hexa (Meth) acrylate, caprolactone-modified pentaerythritol tri (meth) acrylate, capro Kuton modified pentaerythritol tetra (meth) acrylate, ethylene oxide modified dipentaerythritol penta (meth) acrylate, ethylene oxide modified dipentaerythritol hexa (meth) acrylate, ethylene oxide modified pentaerythritol tri (meth) acrylate, ethylene oxide modified pentaerythritol Examples include tetra (meth) acrylate and ethoxylated 15 glycerin triacrylate.

  Also, a Michael adduct of acrylic acid or 2-acryloyloxyethyldicarboxylic acid monoester can be used in combination. Examples of such a Michael adduct of acrylic acid include (meth) acrylic acid dimer, (meth) acrylic acid trimer, (meta ) Acrylic acid tetramer and the like. The 2-acryloyloxyethyl dicarboxylic acid monoester is a carboxylic acid having a specific substituent, for example, 2-acryloyloxyethyl succinic acid monoester, 2-methacryloyloxyethyl succinic acid monoester, 2-acryloyloxy Examples thereof include ethyl phthalic acid monoester, 2-methacryloyloxyethyl phthalic acid monoester, 2-acryloyloxyethyl hexahydrophthalic acid monoester, 2-methacryloyloxyethyl hexahydrophthalic acid monoester, and the like. Furthermore, other oligoester acrylates can be mentioned.

  The content of the ethylenically unsaturated monomer other than the urethane (meth) acrylate is preferably 50% by weight or less, particularly preferably 40% by weight or less, and more preferably, in all the curing components contained in the resin composition. Is 30% by weight or less. The lower limit is usually 5% by weight.

  Examples of the surface conditioner include cellulose resin and alkyd resin. Such a cellulose resin has an action of improving the surface smoothness of the coating film, and an alkyd resin has an action of imparting a film-forming property at the time of coating. These may be used alone or in combination of two or more.

  As the leveling agent, a known general leveling agent can be used as long as it has an effect of imparting wettability to the base material of the coating liquid and a function of reducing the surface tension. For example, a silicone-modified resin, a fluorine-modified resin An alkyl-modified resin or the like can be used. These may be used alone or in combination of two or more.

  As the polymerization inhibitor, the same ones used during the reaction can be used. For example, p-benzoquinone, naphthoquinone, tolquinone, 2,5-diphenyl-p-benzoquinone, hydroquinone, 2,5-di- Quinones such as t-butylhydroquinone, methylhydroquinone, hydroquinone monomethyl ether, mono-t-butylhydroquinone, aromatics such as 4-methoxyphenol and 2,6-di-t-butylcresol, p-t-butylcatechol Etc. These may be used alone or in combination of two or more.

  Moreover, it is also preferable to use the organic solvent for dilution for the active energy ray curable resin composition of this invention as needed, in order to make the viscosity at the time of coating appropriate. Examples of the organic solvent include alcohols such as methanol, ethanol, propanol, n-butanol and i-butanol, ketones such as acetone, methyl isobutyl ketone, methyl ethyl ketone and cyclohexanone, cellosolves such as ethyl cellosolve, toluene and xylene. And the like, glycol ethers such as propylene glycol monomethyl ether, acetates such as methyl acetate, ethyl acetate and butyl acetate, and diacetone alcohol. These organic solvents may be used alone or in combination of two or more.

  When two or more types are used in combination, a combination of glycol ethers such as propylene glycol monomethyl ether and ketones such as methyl ethyl ketone and alcohols such as methanol, or ketones such as methyl ethyl ketone and alcohols such as methanol It is preferable from the viewpoint of the coating film appearance that a combination and two or more kinds selected from alcohols such as methanol are used in combination.

  The active energy ray-curable resin composition of the present invention is effectively used as a curable composition for forming a coating film, such as a top coat agent and an anchor coat agent for various substrates. In addition, after being coated on various substrates and dried, it is not sticky even in an uncured state before curing, that is, a tack-free coating surface can be formed, and a curable resin for coating film formation therefor It is effectively used as a composition. Then, after applying the active energy ray-curable resin composition to the base material (when the resin composition diluted with an organic solvent is applied, after further drying), the active energy ray is irradiated. Cured.

  Examples of the base material to which the active energy ray-curable resin composition of the present invention is applied include, for example, polyolefin resins, polyester resins, polycarbonate resins, acrylonitrile butadiene styrene copolymers (ABS), and polystyrene resins. Plastic substrates such as resins and their molded products (films, sheets, cups, etc.), optical films such as polyethylene terephthalate films, triacetyl cellulose films, cycloolefin films, composite substrates thereof, glass fibers, Composite base materials of the above materials mixed with inorganic materials, metals (aluminum, copper, iron, SUS, zinc, magnesium, alloys thereof, etc.) and glass, or base materials provided with a primer layer on these base materials, etc. Is mentioned.

  Examples of the coating method of the active energy ray-curable resin composition of the present invention include wet coating methods such as spray, shower, gravure, dipping, roll, spin, and screen printing. What is necessary is just to apply to a base material.

  Moreover, the active energy ray-curable resin composition of the present invention may be applied as it is, or may be applied after diluting with an organic solvent. In the case of dilution, the organic solvent is used so that the solid content is usually 3 to 70% by weight, preferably 5 to 60% by weight.

  The drying conditions for dilution with the organic solvent are as follows: the temperature is usually 40 to 120 ° C., preferably 50 to 100 ° C., and the drying time is usually 1 to 20 minutes, preferably 2 to 10 minutes. That's fine.

When applying the active energy ray-curable resin composition of the present invention, the viscosity of the resin composition at 20 ° C. is preferably 5 to 50,000 mPa · s, particularly preferably 10 to 10,000 mPa · s. s, more preferably 50 to 5,000 mPa · s. When the viscosity is out of the above range, the coatability tends to be lowered.
The method for measuring the viscosity at 20 ° C. is based on a B-type viscometer. However, if the B-type viscometer at 20 ° C. cannot be measured due to high viscosity without solvent dilution, the measurement is performed using an E-type viscometer at 60 ° C.

  Examples of the active energy ray used when the active energy ray-curable resin composition coated on the substrate is cured include, for example, deep ultraviolet rays, ultraviolet rays, near ultraviolet rays, infrared rays, X-rays, γ rays, etc. In addition to electromagnetic waves, electron beams, proton beams, neutron beams, and the like can be used, but curing by ultraviolet irradiation is advantageous from the viewpoint of curing speed, availability of an irradiation device, price, and the like. In addition, when performing electron beam irradiation, it can harden | cure even without using photoinitiator [II].

When curing by ultraviolet irradiation, using a high-pressure mercury lamp that emits light in the wavelength range of 150 to 450 nm, an ultra-high pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, a chemical lamp, an electrodeless discharge lamp, an LED lamp, etc. Usually, ultraviolet rays of 30 to 3,000 mJ / cm ² , preferably 100 to 1,500 mJ / cm ² may be irradiated.
After the ultraviolet irradiation, heating can be performed as necessary to complete the curing.

  The coating film thickness (film thickness after curing) is usually 1 to 1,000 μm in consideration of light transmission so that the photopolymerization initiator [II] reacts uniformly as an active energy ray-curable coating film. , Preferably 2 to 500 μm, particularly preferably 3 to 200 μm.

  The active energy ray-curable resin composition of the present invention is preferably used as a coating agent, and particularly preferably used as a hard coat coating agent or an optical film coating agent.

In the present invention, the active energy ray-curable resin composition is applied to a polyethylene terephthalate (PET) film having a size of 15 cm × 15 cm and a thickness of 100 μm so that the cured coating film has a thickness of 10 μm. After drying at a temperature of 60 ° C. for 3 minutes, an 80 W high-pressure mercury lamp is prepared at a height of 18 cm from the surface of the PET film so that the integrated irradiation amount becomes 500 mJ / cm ² at a speed of 5.1 m / min. A cured coating film is obtained by irradiating with ultraviolet rays. The cured coating film is cut out to be 10 cm × 10 cm, and the average value of the height of the four corners of the cut-out cured coating film is 40 mm or less, particularly 30 mm or less, and further a coating that becomes a cured coating film of 20 mm or less. It is preferable to use an agent.

Furthermore, in the present invention, the active energy ray-curable resin composition is applied to an easy-adhesion PET film having a size of 15 cm × 15 cm and a thickness of 125 μm so that the cured coating film has a thickness of 10 μm, and a temperature of 60 After drying at 0 ° C. for 3 minutes, an 80 W high-pressure mercury lamp is prepared at a height of 18 cm from the surface of the easy-adhesive PET film so that the integrated irradiation amount becomes 500 mJ / cm ² at a speed of 5.1 m / min. A cured coating film is obtained by irradiating with ultraviolet rays. The cured coating film was evaluated for flexibility using a cylindrical mandrel bending tester according to JIS K 5600-5-1, and cracked or peeled off when the evaluation cured coating film was wound around a test bar. It is preferable to use a coating agent having a maximum diameter (integer value, mm) of 20 mm or less, particularly 15 mm or less, more preferably 10 mm or less, and particularly 8 mm or less.

  In the present invention, (meth) acrylates (a1) to (a3) in the mixture (A) of the above (meth) acrylates (a1) to (a4), which is a reaction product of pentaerythritol and (meth) acrylic acid, An active energy ray-curable resin composition comprising a urethane (meth) acrylate composition [I] reacted with a polyisocyanate (B), wherein the mixture (A) has a hydroxyl value of 200 mgKOH / g or more. It is a thing. Since this active energy ray-curable resin composition has a small curing shrinkage, it is difficult to curl, and can form a cured coating film having excellent hardness and flexibility, and further, an uncured coating film before curing. However, the coating surface is not sticky and has the effect of being able to form a tack-free coating surface, especially as a coating agent (and hard coating agent and optical film coating agent). It is also useful as a paint or ink.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated further more concretely, this invention is not limited to a following example, unless the summary is exceeded. In the examples, “parts” and “%” mean weight basis.

<Example 1>
[Production of urethane acrylate composition [I-1]]
A four-necked flask equipped with a thermometer, a stirrer, a water-cooled condenser, and a nitrogen gas inlet is equipped with an acrylate mixture (A-1) (pentaerythritol acrylic acid having 36 g of isophorone diisocyanate (B-1) and a hydroxyl value of 288 mgKOH / g. Adduct) 64 g, 100 g of ethyl acetate as a solvent, 0.08 g of 4-methoxyphenol as a polymerization inhibitor, and 0.05 g of dibutyltin dilaurate as a reaction catalyst were reacted at 60 ° C., and the residual isocyanate group was 0.1%. At that time, the reaction was terminated to obtain a urethane acrylate composition [I-1] (resin concentration 50%).
The obtained urethane acrylate composition [I-1] had a weight average molecular weight of 4,700 and a viscosity at 20 ° C. of 80 mPa · s. The viscosity at 20 ° C. was measured using a B-type viscometer. The viscosity measurement at 20 ° C. is the same in the following.

In addition, the content rate of each component with respect to the sum total of the following component (a1)-(a4) in an acrylate mixture (A-1) is as follows.
(A1) Pentaerythritol monoacrylate 4%
(A2) Pentaerythritol diacrylate 29%
(A3) Pentaerythritol triacrylate 49%
(A4) Pentaerythritol tetraacrylate 18%

  In addition, the content rate of each component in a mixture is measured by using a column (The product made by Imtakt, Cadenza CD-C18 100x3mm 3micrometer) for a liquid chromatograph (The product made by Agilent, "Technology HP 1100").

[Production of active energy ray-curable resin composition]
As a photopolymerization initiator [II], 1-hydroxycyclohexyl phenyl ketone (manufactured by IGM, "Omnilad 184") is added to the urethane acrylate composition [I-1] obtained above with respect to 100 parts of a curing component. 4 parts was blended to obtain an active energy ray-curable resin composition.

  About the obtained active energy ray curable resin composition, the coating film (dry coating film) before hardening was formed as follows, and the stickiness of the coating film was evaluated. Furthermore, a cured coating film was formed as described below, and the hardness and flexibility of the cured coating film were evaluated. The evaluation results are as shown in Table 1 below.

[Dry film stickiness]
The active energy ray-curable resin composition obtained above is coated with an adhesive PET film (Toyobo Co., Ltd., “A4300”, size 15 cm × 15 cm, thickness 125 μm) using a bar coater. Was coated to a thickness of 10 μm and dried at 60 ° C. for 3 minutes. Using the tacking tester (“TAC-II” manufactured by Reska Co., Ltd.), the obtained uncured coating film was pushed in at a speed of 120 mm / min, a lifting speed of 600 mm / min, a pressure of 20.4 gf, and a pressurization time of 1.0. The probe tack test was conducted under the condition of seconds.

[Hardness of cured coating film]
The active energy ray-curable resin composition obtained above is coated with an adhesive PET film (Toyobo Co., Ltd., “A4300”, size 15 cm × 15 cm, thickness 125 μm) using a bar coater. Is applied to a thickness of 10 μm, dried at 60 ° C. for 3 minutes, and then irradiated with two passes of UV light at a conveyor speed of 5.1 m / min from a height of 18 cm using a high pressure mercury lamp 80 W and one lamp. (Integrated irradiation amount 500 mJ / cm ² ) was performed to form a cured coating film.
About the said cured coating film coated on the easily-adhesive PET film, the test was done according to JIS K-5600 and pencil hardness was measured.

[Flexibility of cured coating film]
A cured coating film was formed in the same manner as in the above hardness evaluation, and the cured coating film coated on the easy-adhesion PET film was bent using a cylindrical mandrel bending tester according to JIS K 5600-5-1. Sexuality was evaluated. The maximum diameter (integer value, mm) at which cracking or peeling occurred was measured when the evaluation cured coating film was wound around a test bar such that the coating film surface was on the outside. It means that it is a coating film with high flexibility, so that a value is small.

<Example 2>
[Production of Urethane Acrylate Composition [I-2]]
In a four-necked flask equipped with a thermometer, a stirrer, a water-cooled condenser and a nitrogen gas inlet, 33 g of hydrogenated xylylene diisocyanate (B-2) and an acrylate mixture (A-1) (penta) having a hydroxyl value of 288 mgKOH / g Acrylic acid adduct of erythritol) 67 g, 100 g of ethyl acetate as a solvent, 0.08 g of 4-methoxyphenol as a polymerization inhibitor, and 0.05 g of dibutyltin dilaurate as a reaction catalyst were reacted at 60 ° C., and the remaining isocyanate group was 0 The reaction was terminated at 1%, and urethane acrylate composition [I-2] was obtained (resin concentration 50%).
The obtained urethane acrylate composition [I-2] had a weight average molecular weight of 6,200 and a viscosity at 20 ° C. of 65 mPa · s.

  Moreover, using the obtained urethane acrylate composition [I-2], an active energy ray-curable resin composition was obtained in the same manner as in Example 1, and further, the same evaluation as in Example 1 was performed. The evaluation results are as shown in Table 1 below.

<Example 3>
[Production of Urethane Acrylate Composition [I-3]]
In a four-necked flask equipped with a thermometer, a stirrer, a water-cooled condenser, and a nitrogen gas blowing port, 43 g of tolylene diisocyanate (B-3) and an acrylate mixture (A-1) having a hydroxyl value of 288 mgKOH / g (acrylic of pentaerythritol) 97 g of acid adduct), 60 g of ethyl acetate as a solvent, 0.08 g of 4-methoxyphenol as a polymerization inhibitor, and 0.05 g of dibutyltin dilaurate as a reaction catalyst were reacted at 60 ° C., and the residual isocyanate group was 0.1%. At this point, the reaction was terminated to obtain a urethane acrylate composition [I-3] (resin concentration 70%).
The obtained urethane acrylate-based composition [I-3] had a weight average molecular weight of 7,300 and a viscosity at 20 ° C. of 161,000 mPa · s.

  Moreover, after diluting the obtained urethane acrylate-based composition [I-3] with ethyl acetate so as to have a resin content of 50%, an active energy ray-curable resin composition was obtained in the same manner as in Example 1, The same evaluation as in Example 1 was performed. The evaluation results are as shown in Table 1 below.

<Example 4>
[Production of Urethane Acrylate Composition [I-4]]
In a four-necked flask equipped with a thermometer, a stirrer, a water-cooled condenser, and a nitrogen gas blowing port, 48 g of xylylene diisocyanate (B-4) and an acrylate mixture (A-1) having a hydroxyl value of 288 mgKOH / g (acrylic of pentaerythritol) 90 g of acid adduct, 60 g of ethyl acetate as a solvent, 0.08 g of 4-methoxyphenol as a polymerization inhibitor, 0.05 g of dibutyltin dilaurate as a reaction catalyst, reacted at 60 ° C., and 0.1% of the remaining isocyanate groups At this point, the reaction was terminated to obtain a urethane acrylate composition [I-4] (resin concentration 70%).
The weight average molecular weight of the obtained urethane acrylate composition [I-4] was 12,000, and the viscosity at 20 ° C. was not measured because of high viscosity.

  Moreover, after diluting the obtained urethane acrylate composition [I-4] with ethyl acetate so as to have a resin content of 50%, an active energy ray-curable resin composition was obtained in the same manner as in Example 1, and further The same evaluation as in Example 1 was performed. The evaluation results are as shown in Table 1 below.

<Comparative Example 1>
[Production of urethane acrylate composition [I′-1]]
Into a flask equipped with a thermometer, a stirrer, a water-cooled condenser, and a nitrogen gas blowing port, an acrylate mixture (A′-1) (acrylic acid adduct of pentaerythritol) with 38.4 g of isophorone diisocyanate and a hydroxyl value of 120 mg KOH / g 161. 6 g was charged, 0.01 g of hydroquinone methyl ether as a polymerization inhibitor and 0.01 g of dibutyltin dilaurate as a reaction catalyst were allowed to react at 60 ° C. for 8 hours. When the residual isocyanate group became 0.3% or less, the reaction was performed. And urethane acrylate-based composition [I′-1] was obtained (resin concentration 100%).
The resulting urethane acrylate composition [I′-1] had a weight average molecular weight of 1,400 and a viscosity at 60 ° C. of 3,000 mPa · s. However, since it was high viscosity, it measured using the E-type viscosity meter.

In addition, the content rate of each component with respect to the sum total of the following component (a1)-(a4) in an acrylate mixture (A'-1) is as follows.
(A2) Pentaerythritol diacrylate 5%
(A3) Pentaerythritol triacrylate 50%
(A4) Pentaerythritol tetraacrylate 45%
However, since the content of (a1) pentaerythritol monoacrylate was below the measurement limit, the content ratio of the components (a2) to (a4) was shown.

  Moreover, after diluting the obtained urethane acrylate composition [I′-1] with ethyl acetate so as to have a resin content of 50%, an active energy ray-curable resin composition was obtained in the same manner as in Example 1, Furthermore, the same evaluation as in Example 1 was performed. The evaluation results are as shown in Table 1 below.

<Comparative example 2>
[Production of urethane acrylate composition [I'-2]]
In a four-necked flask equipped with a thermometer, a stirrer, a water-cooled condenser, and a nitrogen gas inlet, an acrylate mixture (A-1) of isophorone diisocyanate (B-1) and a hydroxyl value of 288 mgKOH / g (acrylic acid of pentaerythritol) Adduct) 14 g, polyester polyol composed of adipic acid and neopentyl glycol (DIC, “ODX-2044”, number average molecular weight: about 2,000) 114 g, 4-methoxyphenol 0.08 g as a polymerization inhibitor, reaction 0.05 g of dibutyltin dilaurate was added as a catalyst and reacted at 60 ° C. When the residual isocyanate group reached 3.9%, an acrylate mixture (A-1) having a hydroxyl value of 288 mgKOH / g (addition of acrylic acid of pentaerythritol) ) Add 35g, anti-react at 60 ℃ It was. When the residual isocyanate group reached 0.1%, the reaction was terminated to obtain a urethane acrylate composition [I′-2] (resin content concentration 100%).
In addition, according to the said procedure, the urethane acrylate-type composition [I'-2] obtained will not have the reaction material of only (A-1) and (B-1).
The obtained urethane acrylate composition [I′-2] had a weight average molecular weight of 18,000 and a viscosity at 60 ° C. of 700,000 mPa · s. However, since it was high viscosity, it measured using the E-type viscosity meter.

  Moreover, after diluting the obtained urethane acrylate-based composition [I′-2] with ethyl acetate so as to have a resin content of 50%, an active energy ray-curable resin composition was obtained in the same manner as in Example 1, Furthermore, the same evaluation as in Example 1 was performed. The evaluation results are as shown in Table 1 below.

<Comparative Example 3>
[Production of Urethane Acrylate Composition [I′-3]]
In a four-necked flask equipped with a thermometer, a stirrer, a water-cooled condenser, and a nitrogen gas inlet, an acrylate mixture (A′-2) (25.8 g of isophorone diisocyanate (B-1) and hydroxyl value 184.2 mgKOH / g) (A′-2) ( Acrylic acid adduct of pentaerythritol) 74.2 g, 100 g of ethyl acetate as a solvent, 0.08 g of 4-methoxyphenol as a polymerization inhibitor, 0.05 g of dibutyltin dilaurate as a reaction catalyst, and reacted at 60 ° C. The reaction was terminated when the group reached 0.1%, and a urethane acrylate composition [I′-3] was obtained (resin concentration 50%).
The obtained urethane acrylate composition [I′-3] had a weight average molecular weight of 2,100 and a viscosity at 20 ° C. of 73 mPa · s.

In addition, the content rate of each component with respect to the sum total of the following component (a1)-(a4) in an acrylate mixture (A'-2) is as follows.
(A1) Pentaerythritol monoacrylate 1.6%
(A2) Pentaerythritol diacrylate 14.6%
(A3) Pentaerythritol triacrylate 49.6%
(A4) Pentaerythritol tetraacrylate 34.2%

  Moreover, using the obtained urethane acrylate composition [I′-3], an active energy ray-curable resin composition was obtained in the same manner as in Example 1, and further, the same evaluation as in Example 1 was performed. . The evaluation results are as shown in Table 1 below.

<Comparative example 4>
[Production of Urethane Acrylate Composition [I′-4]]
A four-necked flask equipped with a thermometer, a stirrer, a water-cooled condenser, and a nitrogen gas blowing port was charged with 23.3 g of hydrogenated xylylene diisocyanate (B-2) and an acrylate mixture having a hydroxyl value of 184.2 mgKOH / g (A ′ -2) 76.7 g (acrylic acid adduct of pentaerythritol), 100 g of ethyl acetate as a solvent, 0.08 g of 4-methoxyphenol as a polymerization inhibitor, and 0.05 g of dibutyltin dilaurate as a reaction catalyst were reacted at 60 ° C. The reaction was terminated when the residual isocyanate group reached 0.1%, and a urethane acrylate composition [I′-4] was obtained (resin concentration 50%).
The obtained urethane acrylate composition [I′-4] had a weight average molecular weight of 2,200 and a viscosity at 20 ° C. of 85 mPa · s.

  Moreover, using the obtained urethane acrylate-based composition [I′-4], an active energy ray-curable resin composition was obtained in the same manner as in Example 1, and further, the same evaluation as in Example 1 was performed. . The evaluation results are as shown in Table 1 below.

From the above evaluation results, the cured coating film obtained from the active energy ray-curable resin composition containing the urethane acrylate composition [I] of Examples 1 to 4 is excellent in hardness and flexibility, and before curing. It can be seen that even an uncured coating film is not sticky.
On the other hand, in each comparative example using a urethane acrylate composition other than the specific urethane acrylate composition [I], Comparative Example 1 is inferior in the flexibility of the cured coating film. The film was sticky. Moreover, the comparative example 2 was inferior to the hardness of a cured coating film, and also the coating film before hardening had a stickiness. In Comparative Examples 3 and 4, the cured coating film was inferior in flexibility.
From these, the active energy ray-curable resin compositions of the examples are tack-free, have good hardness and flexibility, and are useful in applications such as coating agents, particularly hard coat coating agents and optical film coating agents. I understand that.

  The active energy ray-curable resin composition of the present invention, when a cured coating film is formed, it is difficult to curl due to small curing shrinkage, and can form a coating film having excellent hardness and flexibility. Even if it is coated on a substrate and dried, even if a load is applied, it is not sticky in an uncured state, that is, it can form a tack-free coating surface, and is a coating agent, especially a coating agent for hard coating and an optical film. Useful as a coating agent. It is also useful as a paint or ink. Furthermore, after applying the resin composition side of the uncured laminated film formed on the film to the molded product side and pasting it on the molded product, it is easily applied to various molded products by performing active energy ray curing. A cured film can be formed.

Claims (7)

(Meth) acrylates (a1) to (a3) in a mixture (A) of the following (meth) acrylates (a1) to (a4), which is a reaction product of pentaerythritol and (meth) acrylic acid, and a polyvalent isocyanate ( An active energy ray-curable resin composition comprising a urethane (meth) acrylate-based composition [I] reacted with B), wherein the mixture (A) has a hydroxyl value of 200 mgKOH / g or more. object.
(A1) Pentaerythritol mono (meth) acrylate (a2) Pentaerythritol di (meth) acrylate (a3) Pentaerythritol tri (meth) acrylate (a4) Pentaerythritol tetra (meth) acrylate   The content ratio of pentaerythritol di (meth) acrylate (a2) in the mixture (A) of the (meth) acrylates (a1) to (a4) is 10 to 50% by weight. An active energy ray-curable resin composition.   The active energy ray according to claim 1 or 2, wherein the content ratio of pentaerythritol di (meth) acrylate (a2) to the total of the (meth) acrylates (a1) to (a3) is 15 to 55% by weight. Curable resin composition.   The active energy ray-curable resin according to any one of claims 1 to 3, wherein the urethane (meth) acrylate composition [I] has a weight average molecular weight of 1,000 to 20,000. Composition.   A coating agent comprising the active energy ray-curable resin composition according to any one of claims 1 to 4.   6. The coating agent according to claim 5, which is used as a hard coating agent.   6. The coating agent according to claim 5, which is used as a coating agent for an optical film.