JP7484459B2 - Epoxy (meth)acrylate resin, curable resin composition, cured product and article - Google Patents

Description

The present invention relates to an epoxy (meth)acrylate resin, a curable resin composition, a cured product, and an article.

In recent years, curable compositions, such as active energy ray-curable compositions that can be cured by active energy rays such as ultraviolet rays, and thermosetting compositions that can be cured by heat, have been widely used in the fields of inks, paints, coatings, adhesives, optical components, and the like. In particular, for the above-mentioned coating applications, it is generally required that the coatings can impart design to the surfaces of various substrates, have excellent curing properties, and can form coating films that can prevent deterioration of the substrate surfaces. Furthermore, in recent years, the industrial world has been demanding materials that can form cured coating films that are not only curable but also have elasticity and low linear expansion.

As a material capable of forming a cured coating film having the above-mentioned elasticity, an active energy ray curable composition is known that is characterized by containing, as essential components, an epoxy acrylate resin (A) obtained by reacting a lactone adduct of a hydroxyalkyl (meth)acrylate (a1), a dicarboxylic anhydride (a2), and an epoxy resin (a3), and a radical polymerizable monomer (B) (see, for example, Patent Document 1). However, this does not satisfy the increasingly high performance requirements of recent years.

Therefore, there was a demand for a material capable of forming a cured product with even better elasticity and lower linear expansion.

JP 2003-105230 A

The problem that the present invention aims to solve is to provide an epoxy (meth)acrylate resin having excellent elasticity and low linear expansion in the cured product, a curable resin composition containing the same, a cured product of the curable resin composition, and an article having a coating film of the cured product.

As a result of intensive research into solving the above problems, the inventors discovered that the above problems could be solved by using an epoxy (meth)acrylate resin whose essential raw materials were a specific epoxy resin and an unsaturated monobasic acid, and thus completed the present invention.

That is, the present invention relates to an epoxy (meth)acrylate resin having an epoxy resin (A) and an unsaturated monobasic acid (B) as essential raw materials, characterized in that the epoxy resin (A) is a xanthene type epoxy resin represented by the following general formula (1), a curable resin composition containing the same, and a cured product and article made of the curable resin composition.

〔式（１）中、Ｒ^１、Ｒ^２及びＲ^３はそれぞれ独立して炭素原子数４～８のアルキル基又はアラルキル基であり、ｌは０，１，２のいずれかであり、ｍは０又は１であり、ｎは０又は１であり（但し、ｌ＝ｍ＝ｎ＝０の場合を除く）、Ｒ^４、Ｒ^５はそれぞれ独立して水素原子、炭素原子数４～８のアルキル基又はアラルキル基であり、Ｒ^６、Ｒ^７、Ｒ^８、Ｒ^９はそれぞれ独立して、水素原子、アルキル基又はアリール基であり、Ｒ^６、Ｒ^７、のうちいずれかはアルキル基又はアリール基であり、Ｒ^８、Ｒ^９のうちいずれかはアルキル基又はアリール基であり、ｐ、ｑ、ｒはそれぞれ独立して、０又は１であり（但し、ｐ＝ｑ＝ｒ＝０の場合を除く）、Ｇはグリシジル基であり、ｓは繰り返し数を示し、０～１０の整数である。〕

[In formula (1), R ¹ , R ² and R ³ are each independently an alkyl group or an aralkyl group having 4 to 8 carbon atoms, l is 0, 1 or 2, m is 0 or 1, n is 0 or 1 (except when l=m=n=0), R ⁴ and R ⁵ are each independently a hydrogen atom, an alkyl group or an aralkyl group having 4 to 8 carbon atoms, R ⁶ , R ⁷ , R ⁸ and R ⁹ are each independently a hydrogen atom, an alkyl group or an aryl group, either of R ⁶ and R ⁷ is an alkyl group or an aryl group, either of R ⁸ and R ⁹ is an alkyl group or an aryl group, p, q and r are each independently 0 or 1 (except when p=q=r=0), G is a glycidyl group, and s represents the number of repetitions and is an integer of 0 to 10.]

The epoxy (meth)acrylate resin of the present invention has excellent elasticity and low linear expansion in the cured product, so that a curable resin composition containing the epoxy (meth)acrylate resin and a photopolymerization initiator can be used as a coating agent or adhesive, and is particularly suitable for use as a coating agent. In the present invention, "excellent low linear expansion" means that the linear expansion coefficient of the cured product is low, and "excellent elasticity" means that the elastic modulus of the cured product is high.

FIG. 1 is a ¹³ C-NMR chart of the phenol resin (1) synthesized in Synthesis Example 1. FIG. 2 is an MS chart of the phenol resin (1) synthesized in Synthesis Example 1. FIG. 3 is a GPC chart of the phenol resin (1) synthesized in Synthesis Example 1. FIG. 4 is a ¹³ C-NMR chart of the epoxy resin (2) synthesized in Synthesis Example 2. FIG. 5 is an MS chart of the epoxy resin (2) synthesized in Synthesis Example 2. FIG. 6 is a GPC chart of the epoxy resin (2) synthesized in Synthesis Example 2.

The epoxy (meth)acrylate resin of the present invention is characterized in that it contains an epoxy resin (A) and an unsaturated monobasic acid (B) as essential raw materials.

In the present invention, "(meth)acrylate" means acrylate and/or methacrylate. Furthermore, "(meth)acryloyl" means acryloyl and/or methacryloyl. Furthermore, "(meth)acrylic" means acrylic and/or methacrylic.

The epoxy resin (A) is represented by the following general formula (1):

[In formula (1), R ¹ , R ² and R ³ are each independently an alkyl group or an aralkyl group having 4 to 8 carbon atoms, l is 0, 1 or 2, m is 0 or 1, n is 0 or 1 (except when l=m=n=0), R ⁴ and R ⁵ are each independently a hydrogen atom, an alkyl group or an aralkyl group having 4 to 8 carbon atoms, R ⁶ , R ⁷ , R ⁸ and R ⁹ are each independently a hydrogen atom, an alkyl group or an aryl group, either of R ⁶ and R ⁷ is an alkyl group or an aryl group, either of R ⁸ and R ⁹ is an alkyl group or an aryl group, p, q and r are each independently 0 or 1 (except when p=q=r=0), G is a glycidyl group, and s represents the number of repetitions and is an integer of 0 to 10.]

The epoxy resin (A) has at least one alkyl group or aralkyl group having 4 to 8 carbon atoms in one molecule as R ¹ , R ² , and R ³ in the general formula (1), i.e., as a substituent on an aromatic ring. It is believed that the presence of such a relatively bulky substituent appropriately adjusts the crosslink density during the curing reaction, and reduces the molding shrinkage rate during heat curing. As the alkyl group, an alkyl group having a branched structure such as a t-butyl group, a t-amyl group, or a t-octyl group is preferred, since an epoxy (meth)acrylate resin capable of forming a cured product having excellent elasticity and low linear expansion is obtained, and a t-butyl group or a t-octyl group is more preferred. As the aralkyl group, an aralkyl group having 7 to 15 carbon atoms is preferred, and a benzyl group is more preferred, since an epoxy (meth)acrylate resin capable of forming a cured product having excellent elasticity and low linear expansion is obtained.

In addition, in the general formula (1), R ⁶ , R ⁷ , R ⁸ and R ⁹ are each independently a hydrogen atom, an alkyl group or an aryl group. In particular, when R 6 and R 8 are a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an aryl group having 6 to 14 carbon atoms, an epoxy (meth)acrylate resin capable of forming a cured product having excellent elasticity and low linear expansion can be obtained, and therefore it is preferable that R ⁶ and R ⁸ are an aryl group.

The epoxy resin (A) may be a mixture of multiple compounds with different s in the general formula (1) and a novolac type epoxy resin that does not form a xanthene skeleton, and since an epoxy (meth)acrylate resin capable of forming a cured product with excellent elasticity and low linear expansion can be obtained, the content of s=0 is preferably in the range of 30 to 50% in terms of area ratio measured by gel permeation chromatography (GPC). When s is 0, the general formula (1) is expressed by the following general formula (1-a).

[In formula (1-a), R ¹ and R ² are each independently an alkyl group or an aralkyl group having 4 to 8 carbon atoms, l is 0, 1, or 2, m is 0 or 1 (except when l=m=0), R ⁴ and R ⁵ are each independently a hydrogen atom, an alkyl group or an aralkyl group having 4 to 8 carbon atoms, R ⁶ and R ⁷ are each independently a hydrogen atom, an alkyl group or an aryl group, either R ⁶ or R ⁷ is an alkyl group or an aryl group, p and q are each independently 0 or 1 (except when p=q=0), and G is a glycidyl group.]

Examples of the epoxy resin (A) represented by the general formula (1) include the following structural formulas (1-1) to (1-12). These epoxy resins can be used alone or in combination of two or more. Among these, the structure represented by the following structural formula (1-1) is preferred because it gives an epoxy (meth)acrylate resin capable of forming a cured product having excellent elasticity and low linear expansion.

〔式（１－１）～（１－１２）中、Ｇはグリシジル基を示す。〕

[In formulas (1-1) to (1-12), G represents a glycidyl group.]

The epoxy equivalent of the epoxy resin (A) is preferably in the range of 300 to 500 g/eq, since this results in an epoxy (meth)acrylate resin capable of forming a cured product with excellent elasticity and low linear expansion, and the melt viscosity is preferably in the range of 0.1 to 40 dPa·s at 150°C.

The method for producing the epoxy resin (A) is not particularly limited, and any method may be used. For example, the epoxy resin (A) may be produced by reacting a reaction raw material containing a phenolic resin (A-1) represented by the following general formula (2) with an epihalohydrin (A-2).

〔式（２）中、Ｒ^１、Ｒ^２及びＲ^３はそれぞれ独立して炭素原子数４～８のアルキル基又はアラルキル基であり、ｌは０，１，２のいずれかであり、ｍは０又は１であり、ｎは０又は１であり（但し、ｌ＝ｍ＝ｎ＝０の場合を除く）、Ｒ^４、Ｒ^５はそれぞれ独立して、水素原子、炭素原子数４～８のアルキル基又はアラルキル基であり、Ｒ^６、Ｒ^７、Ｒ^８、Ｒ^９はそれぞれ独立して、水素原子、アルキル基又はアリール基であり、Ｒ^６、Ｒ^７、のうちいずれかはアルキル基又はアリール基であり、Ｒ^８、Ｒ^９のうちいずれかはアルキル基又はアリール基であり、ｐ、ｑ、ｒはそれぞれ独立に０又は１であり（但し、ｐ＝ｑ＝ｒ＝０の場合を除く）、ｓは繰り返し数を示し、０～１０の整数である。〕

[In formula (2), R ¹ , R ² and R ³ are each independently an alkyl group or an aralkyl group having 4 to 8 carbon atoms, l is 0, 1 or 2, m is 0 or 1, n is 0 or 1 (except when l=m=n=0), R ⁴ and R ⁵ are each independently a hydrogen atom, an alkyl group or an aralkyl group having 4 to 8 carbon atoms, R ⁶ , R ⁷ , R ⁸ and R ⁹ are each independently a hydrogen atom, an alkyl group or an aryl group, either R ⁶ or R ⁷ is an alkyl group or an aryl group, either R ⁸ or R ⁹ is an alkyl group or an aryl group, p, q and r are each independently 0 or 1 (except when p=q=r=0), and s represents the number of repetitions and is an integer of 0 to 10.]

The phenolic resin (A-1) has at least one alkyl group or aralkyl group having 4 to 8 carbon atoms in one molecule as R ¹ , R ² , and R ³ in the general formula (2), i.e., as a substituent on the aromatic ring. It is believed that by having such a relatively bulky substituent, the crosslink density during the curing reaction is appropriately adjusted, and the molding shrinkage rate during heat curing is low. As the alkyl group, an alkyl group having a branched structure such as a t-butyl group, a t-amyl group, or a t-octyl group is preferable, since an epoxy (meth)acrylate resin capable of forming a cured product having excellent elasticity and low linear expansion is obtained, and a t-butyl group or a t-octyl group is more preferable. As the aralkyl group, an aralkyl group having 7 to 15 carbon atoms is preferable, and a benzyl group is more preferable, since an epoxy (meth)acrylate resin capable of forming a cured product having excellent elasticity and low linear expansion is obtained.

Examples of the phenol resin (A-1) represented by the general formula (2) include the following structural formulas (2-1) to (2-12). These phenol resins can be used alone or in combination of two or more.

The method for producing the phenolic resin (A-1) is not particularly limited, and any method may be used. For example, a method of producing the phenolic resin (A-1) using a dihydroxybenzene (I) having an alkyl group with 4 to 8 carbon atoms on the aromatic ring and an aldehyde compound (II) having an alkyl group or an aryl group, and an intramolecular ring-closing reaction due to self-oxidation may be used.

Examples of the dihydroxybenzene (I) include monoalkyldihydroxybenzene, dialkyldihydroxybenzene, etc.

Examples of the monoalkyldihydroxybenzene include n-butylhydroquinone, n-butylresorcinol, n-butylcatechol, sec-butylhydroquinone, sec-butylresorcinol, sec-butylcatechol, t-butylhydroquinone, t-butylresorcinol, t-butylcatechol, n-hexylhydroquinone, n-hexylresorcinol, and 4-octylcatechol.

Examples of the dialkyldihydroxybenzene include 3,5-di-t-butylcatechol and 2,5-di-t-butylhydroquinone.

These dihydroxybenzenes can be used alone or in combination of two or more. Among these, those having an alkyl group with a bulkier structure are preferred, as they can produce an epoxy (meth)acrylate resin capable of forming a cured product with excellent elasticity and low linear expansion, and t-butylcatechol and 3,5-di-t-butylcatechol are more preferred.

Examples of the aldehyde compound (II) having an alkyl group or an aryl group include formaldehyde, paraldehyde, benzaldehyde, anisaldehyde, naphthaldehyde, and anthraldehyde. Benzaldehyde is preferred because it gives an epoxy (meth)acrylate resin capable of forming a cured product having excellent elasticity and low linear expansion. When benzaldehyde is used as a raw material, aralkylation occurs, so the desired phenolic resin can be obtained even when unsubstituted dihydroxybenzene is used as a raw material.

The reaction ratio of the dihydroxybenzene (I) and the aldehyde compound (II) is preferably 0.3 to 0.9 moles, more preferably 0.4 to 0.8 moles, of the aldehyde compound (II) per mole of the dihydroxybenzene (I) in the presence of a basic catalyst. After the reaction is completed, it is preferable to neutralize or wash the reaction mixture until the pH value of the reaction mixture reaches 6 to 8. The neutralization or washing can be performed according to a conventional method, and an acidic substance such as sodium phosphate can be used as a neutralizing agent. After the neutralization or washing, the organic solvent can be distilled off under reduced pressure and heating to obtain the desired phenolic resin.

Examples of the basic catalyst include amine compounds such as N-methylmorpholine, pyridine, 1,8-diazabicyclo[5.4.0]undecene-7 (DBU), 1,5-diazabicyclo[4.3.0]nonene-5 (DBN), 1,4-diazabicyclo[2.2.2]octane (DABCO), tri-n-butylamine or dimethylbenzylamine, butylamine, octylamine, monoethanolamine, diethanolamine, triethanolamine, imidazole, 1-methylimidazole, 2,4-dimethylimidazole, 1,4-diethylimidazole, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-(N-phenyl)aminopropyltrimethoxysilane, 3-(2-aminoethyl)aminopropyltrimethoxysilane, 3-(2-aminoethyl)aminopropylmethyldimethoxysilane, and tetramethylammonium hydroxide; trioctylmethylammonium chloride, ... Examples of the quaternary ammonium salts include octylmethylammonium acetate; phosphine compounds such as trimethylphosphine, tributylphosphine, and triphenylphosphine; phosphonium salts such as tetramethylphosphonium chloride, tetraethylphosphonium chloride, tetrapropylphosphonium chloride, tetrabutylphosphonium chloride, tetrabutylphosphonium bromide, trimethyl(2-hydroxypropyl)phosphonium chloride, triphenylphosphonium chloride, and benzylphosphonium chloride; organic tin compounds such as dibutyltin dilaurate, octyltin trilaurate, octyltin diacetate, dioctyltin diacetate, dioctyltin dineodecanoate, dibutyltin diacetate, tin octylate, and 1,1,3,3-tetrabutyl-1,3-dodecanoyldistannoxane; organic metal compounds such as zinc octylate and bismuth octylate; inorganic tin compounds such as tin octanoate; and inorganic metal compounds. In addition, alkaline earth metal hydroxides, alkali metal carbonates, and alkali metal hydroxides can also be used. In particular, alkali metal hydroxides are preferred because they have excellent catalytic activity in the epoxy resin synthesis reaction, and for example, sodium hydroxide and potassium hydroxide are more preferred. These basic catalysts can be used alone or in combination of two or more. When using the basic catalyst, it may be used in the form of an aqueous solution of about 10% by mass to 55% by mass, or in the form of a solid.

The reaction between the dihydroxybenzene (I) and the aldehyde compound (II) may be carried out in an organic solvent, if necessary.

Examples of the organic solvent include ketone solvents such as methyl ethyl ketone, acetone, dimethylformamide, and methyl isobutyl ketone; cyclic ether solvents such as tetrahydrofuran and dioxolane; ester solvents such as methyl acetate, ethyl acetate, and butyl acetate; aromatic solvents such as toluene, xylene, and solvent naphtha; alicyclic solvents such as cyclohexane and methylcyclohexane; alcohol solvents such as carbitol, cellosolve, methanol, isopropanol, butanol, and propylene glycol monomethyl ether; glycol ether solvents such as alkylene glycol monoalkyl ether, dialkylene glycol monoalkyl ether, and dialkylene glycol monoalkyl ether acetate; methoxypropanol, cyclohexanone, methyl cellosolve, diethylene glycol monoethyl ether acetate, and propylene glycol monomethyl ether acetate. These organic solvents can be used alone or in combination of two or more. In addition, the amount of the organic solvent used is preferably in the range of about 0.1 to 5 times the total mass of the reaction raw materials, since this improves the reaction efficiency.

In addition to the dihydroxybenzene (I) and the aldehyde compound (II), the phenolic resin (A-1) may further contain a monohydroxy aromatic compound as a raw material, if necessary. Examples of the monohydroxy aromatic compound include alkylphenols such as phenol, o-cresol, p-cresol, m-cresol, butylphenol, xylenol, nonylphenol, and octylphenol, monocyclic monohydroxy aromatic compounds such as phenylphenol, bisphenol A, bisphenol F, bisphenol S, amylphenol, pyrogallol, allylphenol, and bisphenolfluorenes, and polycyclic monohydroxy aromatic compounds such as 1-naphthol and 2-naphthol. These hydroxy aromatic compounds may be used alone or in combination of two or more.

Examples of the epihalohydrin (A-2) include epichlorohydrin and epibromohydrin. These epihalohydrins can be used alone or in combination of two or more. Among these, epichlorohydrin is preferred because the reaction is easy to control.

The reaction between the phenolic resin (A-1) and the epihalohydrin (A-2) can be carried out, for example, by adding 1 to 10 moles of epihalohydrin (A-2) per mole of hydroxyl groups contained in the phenolic resin (A-1), and then reacting for 0.5 to 10 hours at a temperature of 20 to 120°C while adding 0.9 to 2.0 moles of a basic catalyst per mole of hydroxyl groups in the raw material all at once or gradually. The basic catalyst may be a solid or an aqueous solution thereof. When an aqueous solution is used, it may be added continuously, and water and epihalohydrin may be continuously distilled from the reaction mixture under reduced pressure or normal pressure, and the water may be removed by liquid separation while the epihalohydrin is continuously returned to the reaction mixture.

When carrying out industrial production, all of the epihalohydrin used in the first batch of epoxy resin production is new, but from the next batch onwards, it is preferable to use epihalohydrin recovered from the crude reaction product in combination with new epihalohydrin equivalent to the amount consumed and lost in the reaction. In this case, it may contain impurities such as glycidol derived from the reaction of epichlorohydrin with water, organic solvents, etc. At this time, the epihalohydrin used is not particularly limited, but examples include epichlorohydrin, epibromohydrin, β-methylepichlorohydrin, etc. Among these, epichlorohydrin is preferred because it is easily available industrially.

The epoxy resin obtained by the above-mentioned epoxidation reaction is washed with water as necessary, and unreacted epihalohydrin and the organic solvent used are removed by distillation under heating and reduced pressure. In order to obtain an epoxy resin with even less hydrolyzable halogen, the obtained epoxy resin can be dissolved again in an organic solvent such as toluene, methyl isobutyl ketone, or methyl ethyl ketone, and an aqueous solution of an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide can be added to perform further reaction. In this case, a phase transfer catalyst such as a quaternary ammonium salt or crown ether may be present in order to improve the reaction rate. When a phase transfer catalyst is used, the amount of the catalyst used is preferably in the range of 0.1% by mass to 3.0% by mass relative to the epoxy resin used. After the reaction is completed, the salt formed is removed by filtration, washing with water, or the like, and the solvent such as toluene or methyl isobutyl ketone is further removed by distillation under heating and reduced pressure to obtain a high-purity epoxy resin.

In particular, when reacting the phenolic resin (A-1) with the epihalohydrin (A-2), the desired epoxy resin can be obtained efficiently by setting the water concentration in the solvent to 5 to 25%.

The basic catalyst may be the same as those exemplified above, and the basic catalyst may be used alone or in combination of two or more kinds.

In addition, in the production of the epoxy resin (A), other phenolic compounds can be used in combination as long as the effects of the present invention are not impaired.

The unsaturated monobasic acid (B) refers to a compound having an acid group and a polymerizable unsaturated bond in one molecule. Examples of the acid group include a carboxyl group, a sulfonic acid group, and a phosphoric acid group. Examples of the unsaturated monobasic acid (B) include acrylic acid, methacrylic acid, crotonic acid, cinnamic acid, α-cyanocinnamic acid, β-styrylacrylic acid, and β-furfurylacrylic acid. Esters, acid halides, and acid anhydrides of the unsaturated monobasic acids can also be used. These unsaturated monobasic acids (B) can be used alone or in combination of two or more. Among these, acrylic acid and methacrylic acid are preferred because they can produce epoxy (meth)acrylate resins that can form cured products with excellent elasticity and low linear expansion.

The method for producing the epoxy (meth)acrylate resin of the present invention is not particularly limited, and any method may be used. For example, the resin may be produced by reacting all of the reaction raw materials at once, or by reacting the reaction raw materials sequentially.

The reaction ratio of the epoxy resin (A) and the unsaturated monobasic acid (B) is preferably such that the number of moles of acid groups in the unsaturated monobasic acid (B) per mole of epoxy groups in the epoxy resin (A) is 0.2 to 0.8, and more preferably 0.25 to 0.75, since the resulting epoxy (meth)acrylate resin has an epoxy group and a (meth)acryloyl group, and a low-viscosity epoxy (meth)acrylate resin is obtained. This reaction can be carried out, for example, by heating and stirring in the presence of a suitable basic catalyst at a temperature of about 80 to 140°C. The reaction in step 2 may also be carried out in an organic solvent, if necessary.

The basic catalyst may be the same as those exemplified above, and the basic catalyst may be used alone or in combination of two or more kinds.

The organic solvent may be the same as the organic solvent described above, and the organic solvent may be used alone or in combination of two or more kinds. In addition, the amount of the organic solvent used is preferably in the range of about 0.1 to 5 times the total mass of the reaction raw materials, since this improves the reaction efficiency.

The epoxy (meth)acrylate resin of the present invention has a polymerizable (meth)acryloyl group in its molecular structure, and therefore can be used as a curable resin composition by adding, for example, a photopolymerization initiator.

The photopolymerization initiator may be selected appropriately depending on the type of active energy ray to be irradiated. It may also be used in combination with a photosensitizer such as an amine compound, a urea compound, a sulfur-containing compound, a phosphorus-containing compound, a chlorine-containing compound, or a nitrile compound.

Examples of the photopolymerization initiator include photoradical polymerization initiators such as 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propan-1-one, thioxanthone and thioxanthone derivatives, 2,2'-dimethoxy-1,2-diphenylethan-1-one, diphenyl(2,4,6-trimethoxybenzoyl)phosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, and 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone.

Examples of commercially available photopolymerization initiators include, for example, "Omnirad 1173", "Omnirad 184", "Omnirad 127", "Omnirad 2959", "Omnirad 369", "Omnirad 379", "Omnirad 907", "Omnirad 4265", "Omnirad 1000", "Omnirad 651", "Omnirad TPO", "Omnirad 819", "Omnirad 2022", "Omnirad 2100", "Omnirad 754", "Omnirad 784", "Omnirad 500", "Omnirad 81" (IGM) Resins); "KAYACURE DETX", "KAYACURE MBP", "KAYACURE DMBI", "KAYACURE EPA", "KAYACURE OA" (Nippon Kayaku Co., Ltd.); "Vicure 10", "Vicure 55" (Stoffa Chemical Co.); "Trigonal P1" (Akzo Nobel Co., Ltd.), "SANDORAY 1000" (SANDOZ Co., Ltd.); "DEAP" (Upjohn Chemical Co., Ltd.), "Quantacure PDO", "Quantacure ITX", "Quantacure EPD" (Ward Blenkinsop Co., Ltd.); "Runtecure 1104" (manufactured by Runtec). These photopolymerization initiators can be used alone or in combination of two or more.

The amount of the photopolymerization initiator added is, for example, preferably in the range of 0.05 to 15 mass % relative to the total of the components other than the solvent in the curable resin composition, and more preferably in the range of 0.1 to 10 mass %.

The curable resin composition of the present invention may contain resin components other than the above-mentioned epoxy (meth)acrylate resin (hereinafter, sometimes referred to as "other resin components"). Examples of the other resin components include epoxy resins, various (meth)acrylate monomers, etc.

Examples of the epoxy resin include bisphenol type epoxy resin, phenylene ether type epoxy resin, naphthylene ether type epoxy resin, biphenyl type epoxy resin, triphenylmethane type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol novolac type epoxy resin, naphthol novolac type epoxy resin, naphthol-phenol co-condensed novolac type epoxy resin, naphthol-cresol co-condensed novolac type epoxy resin, phenol aralkyl type epoxy resin, naphthol aralkyl type epoxy resin, dicyclopentadiene-phenol addition reaction type epoxy resin, biphenyl aralkyl type epoxy resin, fluorene type epoxy resin, xanthene type epoxy resin, dihydroxybenzene type epoxy resin, trihydroxybenzene type epoxy resin, etc. These epoxy resins can be used alone or in combination of two or more.

The various (meth)acrylate monomers are not particularly limited as long as they have a (meth)acryloyl group, and examples thereof include aliphatic mono(meth)acrylate compounds such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and octyl (meth)acrylate; alicyclic mono(meth)acrylate compounds such as cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, and adamantyl mono(meth)acrylate; heterocyclic mono(meth)acrylate compounds such as glycidyl (meth)acrylate and tetrahydrofurfuryl acrylate; Mono(meth)acrylate compounds such as aromatic mono(meth)acrylate compounds such as benzyl (meth)acrylate, phenyl (meth)acrylate, phenylbenzyl (meth)acrylate, phenoxy (meth)acrylate, phenoxyethyl (meth)acrylate, phenoxyethoxyethyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, phenoxybenzyl (meth)acrylate, benzyl benzyl (meth)acrylate, and phenylphenoxyethyl (meth)acrylate: (poly)oxyethylene chains, (poly)oxypropylene chains, (poly)oxytetramethylene chains, and other polyoxyalkylene chains are introduced into the molecular structure of the various mono(meth)acrylate monomers described above; lactone-modified mono(meth)acrylate compounds in which a (poly)lactone structure has been introduced into the molecular structure of the various mono(meth)acrylate compounds described above; aliphatic di(meth)acrylate compounds such as ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, butanediol di(meth)acrylate, hexanediol di(meth)acrylate, and neopentyl glycol di(meth)acrylate; 1,4-cyclohexanedimethanol di(meth)acrylate, norbornane di(meth)acrylate, norbornane dimethanol di(meth)acrylate, dicyclopentanyl di(meth)acrylate, and tricyclodecane dimethanol di(meth)acrylate. alicyclic di(meth)acrylate compounds such as aryl esters; aromatic di(meth)acrylate compounds such as biphenol di(meth)acrylate and bisphenol di(meth)acrylate; polyoxyalkylene-modified di(meth)acrylate compounds obtained by introducing a (poly)oxyalkylene chain such as a (poly)oxyethylene chain, a (poly)oxypropylene chain or a (poly)oxytetramethylene chain into the molecular structure of the various di(meth)acrylate compounds described above; lactone-modified di(meth)acrylate compounds obtained by introducing a (poly)lactone structure into the molecular structure of the various di(meth)acrylate compounds described above; aliphatic tri(meth)acrylate compounds such as trimethylolpropane tri(meth)acrylate and glycerin tri(meth)acrylate; (poly)oxyalkylene-modified tri(meth)acrylate compounds in which a (poly)oxyalkylene chain such as a (poly)oxyethylene chain, a (poly)oxypropylene chain, or a (poly)oxytetramethylene chain has been introduced into the molecular structure of an acrylate compound; lactone-modified tri(meth)acrylate compounds in which a (poly)lactone structure has been introduced into the molecular structure of the aliphatic tri(meth)acrylate compound; tetrafunctional or higher aliphatic poly(meth)acrylate compounds such as pentaerythritol tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, or dipentaerythritol hexa(meth)acrylate; (poly)oxyethylene chain, (poly)oxypropylene chain, (poly)oxytetramethylene chain, or the like has been introduced into the molecular structure of the aliphatic poly(meth)acrylate compound; i) 4- or higher functional (poly)oxyalkylene-modified poly(meth)acrylate compounds having a (poly)oxyalkylene chain such as an oxytetramethylene chain introduced therein; 4- or higher functional lactone-modified poly(meth)acrylate compounds having a (poly)lactone structure introduced into the molecular structure of the aliphatic poly(meth)acrylate compounds; hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, trimethylolpropane (meth)acrylate, trimethylolpropane di(meth)acrylate, pentaerythritol (meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol (meth)acrylate, dipentaerythritol di(meth)acrylate acrylate, dipentaerythritol tri(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, ditrimethylolpropane (meth)acrylate, ditrimethylolpropane di(meth)acrylate, ditrimethylolpropane tri(meth)acrylate, etc.; (poly)oxyalkylene modified compounds in which a (poly)oxyalkylene chain such as a (poly)oxyethylene chain, a (poly)oxypropylene chain, or a (poly)oxytetramethylene chain has been introduced into the molecular structure of the hydroxyl group-containing (meth)acrylate compound; lactone modified compounds in which a (poly)lactone structure has been introduced into the molecular structure of the hydroxyl group-containing (meth)acrylate compound; Examples of the (meth)acrylate compounds containing an isocyanate group include acryloyloxyethyl isocyanate, 2-methacryloyloxyethyl isocyanate, and 1,1-bis(acryloyloxymethyl)ethyl isocyanate; glycidyl group-containing (meth)acrylate monomers such as glycidyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate glycidyl ether, and epoxycyclohexylmethyl (meth)acrylate; and epoxy group-containing (meth)acrylate compounds such as mono(meth)acrylates of diglycidyl ether compounds of hydroxybenzene diglycidyl ether, dihydroxynaphthalene diglycidyl ether, biphenol diglycidyl ether, and bisphenol diglycidyl ether. The above-mentioned various (meth)acrylate monomers can be used alone or in combination of two or more kinds.

The curable resin composition of the present invention may also contain various additives, such as a cured product, a curing accelerator, an organic solvent, inorganic fine particles or polymer fine particles, a pigment, an antifoaming agent, a viscosity modifier, a leveling agent, a flame retardant, and a storage stabilizer, as necessary.

The curing agent is not particularly limited as long as it has a functional group capable of reacting with the epoxy group in the epoxy (meth)acrylate resin, and examples thereof include polybasic acids, polybasic acid anhydrides, unsaturated monobasic acids, amine compounds, and amide compounds.

Examples of the polybasic acids include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, maleic acid, fumaric acid, phthalic acid, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, methylhexahydrophthalic acid, citraconic acid, itaconic acid, glutaconic acid, 1,2,3,4-butanetetracarboxylic acid, cyclohexanetricarboxylic acid, cyclohexanetetracarboxylic acid, bicyclo[2.2.1]hepta Examples of the polybasic acid include 2,3-dicarboxylic acid, methylbicyclo[2.2.1]heptane-2,3-dicarboxylic acid, 4-(2,5-dioxotetrahydrofuran-3-yl)-1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic acid, trimellitic acid, pyromellitic acid, naphthalene dicarboxylic acid, naphthalene tricarboxylic acid, naphthalene tetracarboxylic acid, biphenyl dicarboxylic acid, biphenyl tricarboxylic acid, biphenyl tetracarboxylic acid, and benzophenone tetracarboxylic acid. Examples of the polybasic acid include a copolymer of a conjugated diene vinyl monomer and acrylonitrile, and a polymer having a carboxyl group in the molecule. These polybasic acids can be used alone or in combination of two or more.

Examples of the polybasic acid anhydrides include phthalic anhydride, succinic anhydride, trimellitic anhydride, pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, octenylsuccinic anhydride, and tetrapropenylsuccinic anhydride. These polybasic acid anhydrides can be used alone or in combination of two or more.

The unsaturated monobasic acid may be the same as the unsaturated monobasic acid (B) described above, and the unsaturated monobasic acid may be used alone or in combination of two or more kinds.

Examples of the amine compounds include diaminodiphenylmethane, diethylenetriamine, triethylenetetramine, diaminodiphenylsulfone, isophoronediamine, imidazole, BF3-amine complex, guanidine derivatives, etc. These amine compounds can be used alone or in combination of two or more kinds.

Examples of amide compounds include dicyandiamide, polyamide resins synthesized from a dimer of linoleic acid and ethylenediamine, etc. These amide compounds can be used alone or in combination of two or more kinds.

The curing accelerator accelerates the curing reaction, and examples of the accelerator include phosphorus compounds, amine compounds, imidazole, organic acid metal salts, Lewis acids, and amine complex salts. These accelerators can be used alone or in combination of two or more. The amount of the accelerator added is preferably in the range of 0.01 to 10% by mass of the solid content of the curable resin composition.

The organic solvent may be the same as the organic solvents described above, and these organic solvents may be used alone or in combination of two or more kinds.

The cured product of the present invention can be obtained by irradiating the curable resin composition with active energy rays. Examples of the active energy rays include ionizing radiation such as ultraviolet rays, electron beams, α rays, β rays, and γ rays. When ultraviolet rays are used as the active energy rays, irradiation may be performed in an inert gas atmosphere such as nitrogen gas, or in an air atmosphere in order to efficiently carry out the curing reaction by ultraviolet rays.

As a source of ultraviolet light, ultraviolet lamps are generally used from the standpoint of practicality and economy. Specific examples include low-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, xenon lamps, gallium lamps, metal halide lamps, sunlight, LEDs, etc.

The cumulative light amount of the active energy rays is not particularly limited, but is preferably in the range of 10 to 5,000 mJ/cm ² , and more preferably in the range of 50 to 1,000 mJ/cm ^2. When the cumulative light amount is in the above range, it is preferable because the occurrence of uncured parts can be prevented or suppressed.

The irradiation of the active energy rays may be carried out in one step or in two or more steps.

The article of the present invention has a coating film made of the cured product. Examples of the article include plastic molded products such as mobile phones, home appliances, automobile interior and exterior materials, and office automation equipment, as well as semiconductor devices, display devices, and imaging devices.

The present invention will be explained in more detail below with examples and comparative examples.

In this example, the weight average molecular weight (Mw) was measured by gel permeation chromatography (GPC) under the following conditions:

<GPC measurement conditions>
Measurement device: "HLC-8220 GPC" manufactured by Tosoh Corporation,
Column: Guard column "HXL-L" manufactured by Tosoh Corporation
+ Tosoh Corporation "TSK-GEL G2000HXL"
+ Tosoh Corporation "TSK-GEL G2000HXL"
+ Tosoh Corporation "TSK-GEL G3000HXL"
+ Tosoh Corporation "TSK-GEL G4000HXL"
Detector: RI (differential refractometer)
Data processing: Tosoh Corporation "GPC-8020 Model II Version 4.10"
Measurement conditions: Column temperature 40°C
Developing solvent: Tetrahydrofuran
Flow rate: 1.0 ml/min. Standard: In accordance with the measurement manual for the aforementioned "GPC-8020 Model II Version 4.10," the following monodisperse polystyrene with known molecular weight was used.

(Polystyrene used)
"A-500" manufactured by Tosoh Corporation
"A-1000" manufactured by Tosoh Corporation
"A-2500" manufactured by Tosoh Corporation
"A-5000" manufactured by Tosoh Corporation
"F-1" manufactured by Tosoh Corporation
"F-2" manufactured by Tosoh Corporation
"F-4" manufactured by Tosoh Corporation
"F-10" manufactured by Tosoh Corporation
"F-20" manufactured by Tosoh Corporation
"F-40" manufactured by Tosoh Corporation
"F-80" manufactured by Tosoh Corporation
"F-128" manufactured by Tosoh Corporation
Sample: A tetrahydrofuran solution (1.0% by mass, calculated as resin solid content) filtered through a microfilter (50 μl).

In this example, ¹³ C-NMR was measured under the following conditions.

Apparatus: AL-400 manufactured by JEOL Ltd.
Measurement mode: Decoupling with reverse gate,
Solvent: deuterated chloroform,
Pulse angle: 30° pulse,
Sample concentration: 30 wt%,
Accumulation count: 4,000 times.

<MS measurement conditions>
The MS spectrum was measured using a double focusing mass spectrometer "AX505H (FD505H)" manufactured by JEOL Ltd.

(Synthesis Example 1: Synthesis of phenolic resin (1))
In a flask equipped with a thermometer, a cooling tube, and a stirrer, 166 parts by mass (1 mole) of 4-t-butylcatechol, 64 parts by mass (0.6 moles) of benzaldehyde, and 230 parts by mass of xylene were charged and dissolved while purging with nitrogen gas. After heating to 140°C, 14 parts by mass (0.17 moles) of 49% by mass aqueous sodium hydroxide solution was added, and the temperature was raised to 150°C and reacted for 6 hours. Then, the temperature was raised to 200°C while removing xylene and water, and the reaction was continued for another 18 hours. After the reaction was completed, 400 parts by mass of xylene was added, the mixture was cooled to 80°C, and the mixture was neutralized and washed with water, and the washing liquid was washed three times with 200 parts by mass of water until the pH of the washing liquid became neutral. Next, the system was dehydrated by azeotropy, and after passing through precision filtration, the solvent was distilled off under reduced pressure to obtain a phenolic resin (1). The hydroxyl group equivalent of this phenolic resin (1) was 188 g/eq. The GPC chart of the phenol resin (1) is shown in Figure 1, ^{the 13} C-NMR chart is shown in Figure 2, and the MS spectrum is shown in Figure 3. From the GPC, the content of the substance represented by the following structural formula was 66%.

(Synthesis Example 2: Synthesis of epoxy resin (1))
In a flask equipped with a thermometer, a condenser, and a stirrer, 188 parts by mass of the phenolic resin (1) obtained in Synthesis Example 1 (hydroxyl equivalent: 1.0 g/eq), 555 parts by mass (6.0 moles) of epichlorohydrin, and 53 parts by mass of n-butanol were charged and dissolved while purging with nitrogen gas. After heating to 50°C, 220 parts by mass (1.10 moles) of a 20% by mass aqueous sodium hydroxide solution were added over 3 hours, and then the mixture was further reacted at 50°C for 1 hour. After the reaction was completed, unreacted epichlorohydrin was distilled off under reduced pressure at 150°C. Next, 300 parts by mass of methyl isobutyl ketone and 50 parts by mass of n-butanol were added to the obtained crude epoxy resin and dissolved. Further, 15 parts by mass of a 10% by mass aqueous sodium hydroxide solution was added to this solution and reacted at 80°C for 2 hours, and then the mixture was washed three times with 100 parts by mass of water until the pH of the washing liquid became neutral. The system was then dehydrated by azeotropy, and after microfiltration, the solvent was distilled off under reduced pressure to obtain epoxy resin (1). The epoxy equivalent of this epoxy resin was 376 g/eq. The GPC chart of epoxy resin (1) is shown in Figure 4, its ¹³ C-NMR spectrum is shown in Figure 5, and its FD-MS spectrum is shown in Figure 6. The content of the substance represented by the following structural formula was found to be 48% from GPC.

(Comparative Synthesis Example 1: Synthesis of phenolic resin (2))
In a 1-liter four-neck flask equipped with a stirrer and a heater, 152 parts by mass (1.0 mol) of trimethylhydroquinone was dissolved in a mixed solvent of 500 parts by mass of toluene and 200 parts by mass of ethylene glycol monoethyl ether. 4.6 parts by mass of paratoluenesulfonic acid was added to the solution, and 64 parts by mass (0.6 mol) of benzaldehyde was added dropwise while being careful not to generate heat, and the mixture was stirred at 100 to 120°C for 15 hours while distilling off water. The mixture was then cooled, and the precipitated crystals were filtered off, washed repeatedly with water until neutral, and then dried to obtain phenolic resin (2).

(Comparative Synthesis Example 2: Synthesis of Epoxy Resin (2))
Epoxy resin (2) was obtained in the same manner as in Synthesis Example 2, except that the phenolic resin (A-1) used in Synthesis Example 2 was changed to 187 parts by mass of phenolic resin (2) (hydroxyl group equivalent: 1.0 g/eq). The epoxy equivalent of the obtained epoxy resin (2) was 272 g/eq.

(Example 1: Preparation of epoxy acrylate resin (1))
In a flask equipped with a thermometer, a stirrer, and a reflux condenser, 103 parts by mass of butyl acetate and 376 parts by mass of the epoxy resin (1) obtained in Synthesis Example 2 were added, 0.21 parts by mass of dibutylhydroxytoluene as an antioxidant and 0.21 parts by mass of methoquinone as a thermal polymerization inhibitor were added, and then 36 parts by mass of acrylic acid and 0.21 parts by mass of triphenylphosphine were added, and an esterification reaction was carried out at 100 ° C. for 13 hours while blowing air. After confirming that the acid value was 1 mg KOH / g or less, 0.21 parts by mass of oxalic acid was added. The mixture was stirred at 70 ° C. for 3 hours to obtain the desired epoxy acrylate resin (1). The epoxy equivalent of the solid content of this epoxy acrylate resin (1) was 835 (g / eq). In addition, the number of moles of acrylic acid per mole of epoxy group in the epoxy resin (1) was 0.5.

(Example 2: Preparation of epoxy acrylate resin (2))
In a flask equipped with a thermometer, a stirrer, and a reflux condenser, 112 parts by mass of butyl acetate and 376 parts by mass of the epoxy resin (1) obtained in Synthesis Example 2 were added, 0.44 parts by mass of dibutylhydroxytoluene as an antioxidant and 0.22 parts by mass of methoquinone as a thermal polymerization inhibitor were added, and then 72 parts by mass of acrylic acid and 2.2 parts by mass of triphenylphosphine were added, and an esterification reaction was carried out at 120° C. for 10 hours while blowing in air, to obtain the desired epoxy acrylate resin (2). The epoxy equivalent of the solid content of this epoxy acrylate resin (2) was 12050 (g/eq). The number of moles of acrylic acid per mole of epoxy group in the epoxy resin (1) was 1.0.

(Example 3: Preparation of epoxy acrylate resin (3))
In a flask equipped with a thermometer, a stirrer, and a reflux condenser, 43 parts by mass of butyl acetate and 376 parts by mass of the epoxy resin (1) obtained in Synthesis Example 2 were added, 0.19 parts by mass of dibutylhydroxytoluene as an antioxidant and 0.19 parts by mass of methoquinone as a thermal polymerization inhibitor were added, and then 10.8 parts by mass of acrylic acid and 0.19 parts by mass of triphenylphosphine were added, and an esterification reaction was carried out at 100 ° C. for 8 hours while blowing air. After confirming that the acid value was 1 mg KOH / g or less, 0.19 parts by mass of oxalic acid was added. The mixture was stirred at 70 ° C. for 3 hours to obtain the desired epoxy acrylate resin (3). The epoxy equivalent of the solid content of this epoxy acrylate resin (3) was 471 (g / eq). In addition, the number of moles of acrylic acid per mole of epoxy group in the epoxy resin (1) was 0.15.

(Example 4: Preparation of epoxy acrylate resin (4))
In a flask equipped with a thermometer, a stirrer, and a reflux condenser, 43.8 parts by mass of butyl acetate and 376 parts by mass of the epoxy resin (1) obtained in Synthesis Example 2 were added, 0.2 parts by mass of dibutylhydroxytoluene as an antioxidant and 0.2 parts by mass of methoquinone as a thermal polymerization inhibitor were added, and then 18 parts by mass of acrylic acid and 0.2 parts by mass of triphenylphosphine were added, and an esterification reaction was carried out at 100 ° C. for 10 hours while blowing air. After confirming that the acid value was 1 mg KOH / g or less, 0.2 parts by mass of oxalic acid was added. The mixture was stirred at 70 ° C. for 3 hours to obtain the desired epoxy acrylate resin (4). The epoxy equivalent of the solid content of this epoxy acrylate resin (4) was 543 (g / eq). In addition, the number of moles of acrylic acid per mole of epoxy group in the epoxy resin (1) was 0.25.

(Example 5: Preparation of epoxy acrylate resin (5))
In a flask equipped with a thermometer, a stirrer, and a reflux condenser, 107.5 parts by mass of butyl acetate and 376 parts by mass of the epoxy resin (1) obtained in Synthesis Example 2 were added, 0.43 parts by mass of dibutylhydroxytoluene as an antioxidant and 0.22 parts by mass of methoquinone as a thermal polymerization inhibitor were added, and then 54 parts by mass of acrylic acid and 1.7 parts by mass of triphenylphosphine were added, and an esterification reaction was carried out at 100 ° C. for 10 hours while blowing air. After confirming that the acid value was 1 mg KOH / g or less, 1.7 parts by mass of oxalic acid were added. The mixture was stirred at 70 ° C. for 3 hours to obtain the desired epoxy acrylate resin (5). The epoxy equivalent of the solid content of this epoxy acrylate resin (5) was 1805 (g / eq). In addition, the number of moles of acrylic acid per mole of epoxy group in the epoxy resin (1) was 0.75.

(Example 6: Preparation of epoxy acrylate resin (6))
In a flask equipped with a thermometer, a stirrer, and a reflux condenser, 109.3 parts by mass of butyl acetate and 376 parts by mass of the epoxy resin (1) obtained in Synthesis Example 2 were added, 0.44 parts by mass of dibutylhydroxytoluene as an antioxidant and 0.22 parts by mass of methoquinone as a thermal polymerization inhibitor were added, and then 61.2 parts by mass of acrylic acid and 1.7 parts by mass of triphenylphosphine were added, and an esterification reaction was carried out at 100 ° C. for 12 hours while blowing air. After confirming that the acid value was 1 mg KOH / g or less, 1.7 parts by mass of oxalic acid were added. The mixture was stirred at 70 ° C. for 3 hours to obtain the desired epoxy acrylate resin (6). The epoxy equivalent of the solid content of this epoxy acrylate resin (6) was 3071 (g / eq). In addition, the number of moles of acrylic acid per mole of epoxy group in the epoxy resin (1) was 0.85.

(Comparative Example 1: Preparation of epoxy acrylate resin (R1))
In a flask equipped with a thermometer, a stirrer, and a reflux condenser, 272 parts by mass of the epoxy resin (2) obtained in Comparative Synthesis Example 2 was added, 0.15 parts by mass of dibutylhydroxytoluene as an antioxidant, and 0.15 parts by mass of methoquinone as a thermal polymerization inhibitor were added, and then 36 parts by mass of acrylic acid and 0.15 parts by mass of triphenylphosphine were added, and an esterification reaction was carried out at 100°C for 10 hours while blowing in air. After confirming that the acid value was 1 mgKOH/g or less, 0.15 parts by mass of oxalic acid was added. The mixture was stirred at 70°C for 3 hours to obtain an epoxy acrylate resin (R1). The epoxy equivalent of this epoxy acrylate resin (R1) was 629 (g/eq).

(Example 7: Preparation of curable resin composition (1))
50 parts by mass of the epoxy acrylate resin (1) obtained in Example 1, 50 parts by mass of an acrylate monomer, 1 part by mass of diethylene glycol monoethyl ether acetate, 5 parts by mass of a photopolymerization initiator (manufactured by IGM Resins, "Omnirad 907"), and 3 parts by mass of a photopolymerization initiator (manufactured by IGM Resins, "Omnirad TPO") were mixed to obtain a curable resin composition (1).

(Examples 8 to 12: Preparation of curable resin compositions (2) to (6))
Curable resin compositions (2) to (6) were obtained in the same manner as in Example 7, except that the epoxy acrylate resin (1) used in Example 7 was replaced with the epoxy acrylate resins (2) to (6) obtained in Examples 2 to 6 in the blending amounts shown in Table 1.

(Comparative Example 2: Preparation of Curable Resin Composition (R1))
A curable resin composition (R1) was obtained in the same manner as in Example 7, except that the epoxy acrylate resin (R1) obtained in Comparative Example 1 was used in place of the epoxy acrylate resin (1) used in Example 7 in the blending amount shown in Table 1.

The following evaluations were carried out using the curable resin compositions (1) to (6) and (R1) obtained in the above examples and comparative examples.

[Method for evaluating linear expansion properties]
The linear expansion property was evaluated by measuring the average linear expansion coefficient.

<Preparation of test specimen>
The curable resin compositions obtained in the Examples and Comparative Examples were applied to an electrolytic copper foil "F2-WS" manufactured by Furukawa Sangyo Kaisha, Ltd. using an applicator to a thickness of 50 μm, and dried at 80° C. for 30 minutes. Next, the dried coating film was irradiated with ultraviolet light at 1000 mJ/cm ² using a metal halide lamp, and then heated at 160° C. for 1 hour. The obtained laminate was cut into a size of 20 mm x 5 mm to obtain a test piece.

<Measurement of average linear expansion coefficient>
The test pieces were subjected to thermomechanical analysis in a tensile mode under a nitrogen atmosphere under the following measurement conditions using a thermomechanical analyzer (TMA: "TMA-60" manufactured by Shimadzu Corporation). The measurement was performed twice for the same sample, and the average linear expansion coefficient in the temperature range of 40°C to 60°C in the second measurement was evaluated as the linear expansion coefficient (10 ^-6 /°C).

Measurement conditions: Measurement load 50mN, heating rate 10℃/min, twice, measurement temperature range (first time) 25℃ to 220℃, (second time) -40℃ to 220℃

[Method of evaluating elasticity]
The elasticity was measured based on a tensile test.

<Preparation of test specimen>
The curable resin compositions obtained in the Examples and Comparative Examples were applied to the electrolytic copper foil "F2-WS" using a 50 μm applicator and dried at 80° C. for 30 minutes. After irradiating with ultraviolet light of 1000 mJ/ ^cm2 using a metal halide lamp, the composition was heated at 160° C. for 1 hour. The cured product was peeled off from the electrolytic copper foil "F2-WS" to obtain a test piece (cured product).

<Tensile test>
The test specimen was cut into a size of 10 mm x 80 mm, and a tensile test was performed on the test specimen under the following measurement conditions using a precision universal testing machine "Autograph AG-IS" manufactured by Shimadzu Corporation. The elastic modulus (MPa) until the test specimen broke was measured.

Measurement conditions: Temperature 23°C, humidity 50%, gauge length 20 mm, support length 20 mm, tensile speed 10 mm/min

The compositions and evaluation results of the curable resin compositions (1) to (6) prepared in Examples 7 to 12 and the curable resin composition (R1) prepared in Comparative Example 2 are shown in Table 1.

In addition, "Acrylate Monomer" in Table 1 refers to EO-modified diacrylate of bisphenol A ("Miramaer M240" manufactured by Miwon Specialty Chemical Co., Ltd.).

Examples 7 to 12 shown in Table 1 are examples of curable resin compositions using the epoxy acrylate resin of the present invention. It was confirmed that the epoxy acrylate resin of the present invention has a low linear expansion coefficient, excellent low linear expansion properties, and excellent elasticity.

On the other hand, Comparative Example 2 is an example of a curable resin composition that does not use the epoxy resin of the present invention. It was confirmed that this curable resin composition has insufficient low linear expansion properties and is also significantly insufficient in terms of elasticity.

Claims (10)

An epoxy resin (A),
An unsaturated monobasic acid (B);
An epoxy (meth)acrylate resin comprising the following as an essential raw material:
The epoxy equivalent of the epoxy resin (A) is in the range of 300 to 500 g/eq,
The epoxy (meth)acrylate resin is characterized in that the epoxy resin (A) contains a xanthene type epoxy resin represented by the following general formula (1 -a ):
[In formula (1-a), R ¹ and R ² are each independently an alkyl group or aralkyl group having a branched structure and having 4 to 8 carbon atoms, l is 0, 1, or 2, m is 0 or 1 (except when l=m=0), R ⁴ and R ⁵ are each independently a hydrogen atom, an alkyl group or an aralkyl group having 4 to 8 carbon atoms, R ⁶ and R ⁷ are each independently a hydrogen atom, an alkyl group or an aryl group, either R ⁶ or R ⁷ is an alkyl group or an aryl group, p and q are each independently 0 or 1 (except when p=q=0), and G is a glycidyl group.] The epoxy (meth)acrylate resin according to claim 1, wherein R ⁶ in the general formula (1 -a ) is an aryl group. 3. The epoxy (meth)acrylate resin according to claim 1, wherein the content of the compound represented by the general formula (1 -a ) is in the range of 30 to 50% in terms of area ratio in GPC measurement. The epoxy (meth)acrylate resin according to any one of claims 1 to 3 , wherein the number of moles of acid groups contained in the unsaturated monobasic acid (B) relative to 1 mole of epoxy groups contained in the epoxy resin (A) is in the range of 0.2 to 0.8. The epoxy (meth)acrylate resin according to any one of claims 1 to 4 , which has an epoxy group and a (meth)acryloyl group. A curable resin composition comprising the epoxy (meth)acrylate resin according to any one of claims 1 to 5 and a photopolymerization initiator. The curable resin composition according to claim 6, further comprising an organic solvent. The curable resin composition according to claim 6 or 7 , further comprising a (meth)acrylate monomer. A cured product of the curable resin composition according to any one of claims 6 to 8 . An article having a coating film comprising the cured product according to claim 9 .