JPH04261421A - Energy ray curable resin composition for casting - Google Patents

Abstract

PURPOSE:To obtain an energy ray curable resin composition for casting, satisfying performance such as excellent curing sensitivity with energy ray, small curing shrinkage and excellent curing properties of deep part required for energy ray curable resins. CONSTITUTION:An energy ray curable resin composition for casting comprising as essential components (a) an energy ray curable cationic polymerizable organic substance containing a specific aromatic epoxy resin, a specific alicyclic epoxy resin and an epoxy resin containing a specific organic group and (b) an energy ray-sensitive cationic polymerization initiator in a specific ratio and an energy ray curable resin composition for casting comprising the component (a), the component (b), (c) an acrylate or methacrylate compound and (d) a radical polymerization initiator in a specific weight ratio.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an energy beam-curable resin composition for casting.

0002

2. Description of the Related Art As one of the resin molding methods, a casting method is widely used in which a reactive liquid resin such as epoxy resin, polyester resin, or polyurethane resin is injected into a mold. However, in conventional casting methods using epoxy resins, polyester resins, polyurethane resins, etc., the resin used is a two-component type, which requires a long time for operations such as measuring, defoaming, and mixing.

[0003] Recently, a casting method using an energy ray-curable resin that solves these problems has been attracting attention. The performance required of this energy ray curable resin composition for casting is excellent curing sensitivity to energy rays, small curing shrinkage, and excellent deep curability.
Good UV transmittance after curing, low viscosity,
Examples include good thermal stability of the liquid resin, good mechanical properties of the cured product, and good releasability from the casting mold.

[0004] JP-A-62-5819, JP-A-62
-189121 Publication, JP-A-1-317722, JP-A-60-71629, JP-A-59-454
No. 90 describes a casting method using an energy ray curable resin, and the energy ray curable resin compositions described in these inventions are the same as the energy ray curable resin composition for casting. However, it did not satisfy all of the performance requirements.

[0005] Furthermore, Japanese Patent Application Laid-open No. 62-5819, Japanese Patent Application Publication No. 189121-1980, and Japanese Patent Application Laid-Open No. 1-31772
Publication No. 2 and Japanese Patent Publication No. 59-45490 use radically polymerizable resins such as acrylate resins as energy ray-curable resins, but these radically polymerizable resins have good reactivity with energy rays. However, because of large curing shrinkage and high viscosity, it had the disadvantage of poor precision in casting.

[0006] Furthermore, Japanese Patent Application Laid-Open No. 60-71629,
A mixture of epoxy resin, an aluminum compound, and a silicon compound that generates silanol groups when irradiated with light is used as the energy ray-curable resin, and although the curing shrinkage is small, the curing speed with energy rays is poor, and the time required for casting is longer. It had the following drawback.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a resin composition suitable for a resin casting system using active energy rays, which eliminates the above-mentioned drawbacks.

[0008]

[Means for Solving the Problems] As a result of intensive study of energy beam curable resins having various properties required for energy beam curable resin compositions for casting, the present inventors have found the following. It has been found that the composition has particularly excellent properties.

One of the energy ray-curable resin compositions for casting according to the present invention is an aromatic epoxy resin (a- 30% by weight or more of 1), 30% by weight or more of alicyclic epoxy resin (a-2) having at least two or more cyclohexene oxide groups in one molecule, and an epoxy resin having one epoxy group in one molecule. Resin (a-3-1), or epoxy resin (a-3-2) having both one or more cyclohexene oxide groups and one or more alkylene oxide groups in one molecule, or 1
Any one or more epoxy resin (a-3-3) of aliphatic epoxy resins having two or more epoxy groups in the molecule (
an energy beam-curable cationically polymerizable organic substance (a) containing 0.1 to 30% by weight of a-3); and an energy-beam-sensitive cationic polymerization initiator (b); The weight ratio of the substance (a) and the energy ray-sensitive cationic polymerization initiator (b) is 98.00:2.00 to 99.99:0.0.
1.

Another aspect of the energy ray-curable resin composition for casting of the present invention is an aromatic epoxy resin derived from bisphenols and having at least two epoxy groups in one molecule ( 30% by weight of a-1)
Above, 3 alicyclic epoxy resins (a-2) having at least two or more cyclohexene oxide groups in one molecule
0% by weight or more, an epoxy resin (a-3-1) having one epoxy group in one molecule, or an epoxy resin having both one or more cyclohexene oxide group and one or more alkylene oxide group in one molecule (a-3-2) or an aliphatic epoxy resin (a-3-3) having two or more epoxy groups in one molecule. Contains an energy beam-curable cationic polymerizable organic substance (a) containing 30% by weight, an energy beam-sensitive cationic polymerization initiator (b), an acrylate compound or methacrylate compound (c), and a radical polymerization initiator (d). , the blending ratio of the energy beam-curable cationic polymerizable organic substance (a) and the energy beam-sensitive cationic polymerization initiator (b) is 9 by weight.
8.00:2.00 to 99.99:0.01, and the total amount of the energy ray-curable cationic polymerizable organic substance (a) and the energy ray-sensitive cationic polymerization initiator (b) and the acrylate compound or methacrylate compound. (c)
The weight ratio of the radical polymerization initiator (d) to the energy beam-curable cationic polymerizable organic substance (a) and the energy beam-sensitive cationic polymerization initiator (b) is in the range of 60:40 to 98:2. It is characterized in that it is contained in an amount of 0.01 to 4 parts by weight based on 100 parts by weight of the total amount of the acrylate compound or methacrylate compound (c). Here, the aromatic epoxy resin (a-1) having at least two or more epoxy groups in one molecule derived from bisphenols refers to bisphenols such as bisphenol A, bisphenol F, and hydrogenated bisphenol A, or These include glycidyl ethers produced by reacting derivatives thereof such as alkylene oxide adducts and caprolactone adducts with epichlorohydrin, and novolac epoxy resins, such as bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, hydrogenated bisphenol. A diglycidyl ether, hydrogenated bisphenol F diglycidyl ether, bisphenol A diglycidyl ether with 1 mole of ethylene oxide, bisphenol A diglycidyl ether with 2 moles of ethylene oxide, propylene oxide 4
Bisphenol A diglycidyl ether with moles added, Bisphenol F diglycidyl ether with 2 moles of ethylene oxide, Bisphenol F diglycidyl ether with 4 moles of propylene oxide, 2 moles of ethylene oxide
molar addition hydrogenated bisphenol A diglycidyl ether,
4 mol propylene oxide hydrogenated bisphenol A
diglycidyl ether, hydrogenated bisphenol F diglycidyl ether with 2 moles of ethylene oxide, hydrogenated bisphenol F diglycidyl ether with 4 moles of propylene oxide, bisphenol A diglycidyl ether with 2 moles of ε-caprolactone, ε-caprolactone 2
Molar addition bisphenol F diglycidyl ether, ε-
Hydrogenated bisphenol A diglycidyl ether added with 2 moles of caprolactone, hydrogenated bisphenol F diglycidyl ether added with 2 moles of ε-caprolactone, phenol novolac epoxy resin, and orthocresol novolac epoxy resin. The aromatic epoxy resin (a-1) having at least two or more epoxy groups in one molecule derived from these bisphenols can be used alone or in combination of two or more types depending on the desired performance. I can do that.

Among the aromatic epoxy resins (a-1) having at least two epoxy groups in one molecule derived from these bisphenols, preferred are bisphenol A diglycidyl ether and bisphenol F diglycidyl ether. , hydrogenated bisphenol A diglycidyl ether, bisphenol A diglycidyl ether added with 1 mole of ethylene oxide, bisphenol A diglycidyl ether added with 2 moles of ethylene oxide, phenol novolac epoxy resin, orthocresol novolac epoxy resin, and particularly preferred are bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, phenol novolac epoxy resin, and orthocresol novolac epoxy resin.

Alicyclic epoxy resin having at least two or more cyclohexene oxide groups in one molecule (a-2
) is cyclohexene oxide obtained by epoxidizing a polyglycidyl ether of a polyhydric alcohol having an alicyclic ring or a compound containing a cyclohexene or cyclopentene ring with an appropriate oxidizing agent such as hydrogen peroxide or peracid. or an alicyclic epoxy resin such as a cyclopentene oxide-containing compound, typical examples of which include 3
, 4-epoxycyclohexylmethyl-3',4'-epoxycyclohexanecarboxylate, 2-(3,4
-Epoxycyclohexyl-5,5-spiro-3,4-
epoxy) cyclohexane-meta-dioxane, bis(
3,4-epoxycyclohexylmethyl)adipate,
Bis(3,4-epoxy-6-methylcyclohexyl-
3,4-epoxy-6-methylcyclohexanecarboxylate, methylenebis(3,4-epoxycyclohexane), dicyclopentadiene diepoxide, di(3,4-epoxycyclohexylmethyl)ether of ethylene glycol, ethylenebis(3,4-epoxycyclohexanecarboxylate) -epoxycyclohexane carboxylate). These alicyclic epoxy resins (a-2) having at least two or more cyclohexene oxide groups in one molecule can be used alone or in combination of two or more types depending on the desired performance. . Among the alicyclic epoxy resins (a-2) having at least two or more cyclohexene oxide groups in one molecule, preferred ones have at least two cyclohexene oxide groups in one molecule.
Alicyclic epoxy resins having cyclohexene oxide groups, particularly preferred are 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexanecarboxylate and bis(3,4-epoxycyclohexylmethyl). It is adipate.

The epoxy resin (a-3-1) having one epoxy group in one molecule refers to an aliphatic or aromatic epoxy resin (a-3-1).
hydric alcohols, phenols or derivatives thereof such as alkylene oxide adducts and caprolactone adducts;
Glycidyl ether produced by reaction with epichlorohydrin, or a compound containing one cyclohexene or cyclopentene ring in the molecule, is treated with hydrogen peroxide,
Monocyclohexene oxide obtained by epoxidation with a suitable oxidizing agent such as peracid, or monoalicyclic epoxy resin such as a compound containing monocyclopentene oxide, and monoglycidyl ester of aliphatic long-chain monobasic acid. For example, glycidyl ether of monoalcohol with 12 to 13 carbon atoms, monoglycidyl ether of isopropyl alcohol, monoglycidyl ether of dodecanol, monoglycidyl ether of phenol, phenol monoglycidyl ether with 2 moles of ethylene oxide added, phenol monoglycidyl ether with 4 moles of ethylene oxide added. Ether, 2 moles of ε-caprolactone added phenol monoglycidyl ether, 4 ε-caprolactone
Molar addition of phenol monoglycidyl ether, nonylphenol monoglycidyl ether, nonylphenol monoglycidyl ether with 2 moles of ethylene oxide, nonylphenol monoglycidyl ether with 4 moles of ethylene oxide, nonylphenol monoglycidyl ether with 2 moles of ε-caprolactone, 4 moles of ε-caprolactone Nonylphenol monoglycidyl ether, 2-ethylhexyl carbitol monoglycidyl ether, vinylcyclohexene monooxide, 4-
Vinyl epoxycyclohexane, dioctyl epoxyhexahydrophthalate, di-2-ethylhexyl epoxyhexahydrophthalate, monoglycidyl ether of aliphatic higher alcohol, phenol, cresol, butylphenol, or polyether obtained by adding alkylene oxide to these. Examples include monoglycidyl ethers of alcohols and glycidyl esters of higher fatty acids. These epoxy resins (a-3-1) having one epoxy group in one molecule can be used alone or in combination of two or more kinds depending on the desired performance.

The epoxy resin (a-3-2) having both one or more cyclohexene oxide groups and one or more alkylene oxide groups in one molecule is a compound containing a cyclohexene ring and an alkylene group in the molecule, It is a compound obtained by epoxidation with an appropriate oxidizing agent such as hydrogen peroxide or peracid, such as vinylcyclohexene dioxide, epoxyhexahydrophthalic acid diglycidyl ester, glycidyl-3,4-epoxycyclohexanecarboxylic acid, etc. One example is the rate. 1 of these
Epoxy resin (a
-3-2) can be used alone or in combination of two or more kinds depending on the desired performance.

[0015] The aliphatic epoxy resin (a-3-3) having two or more epoxy groups in one molecule refers to aliphatic polyhydric alcohol or its alkylene oxide adduct polyglycidyl ether, aliphatic long chain polyhydric alcohol, or polyglycidyl ether of its alkylene oxide adduct. Aliphatic epoxy resins such as polyglycidyl esters of basic acids, homopolymers and copolymers of glycidyl acrylate and glycidyl methacrylate, and representative examples include diglycidyl ether of 1,4-butanediol and diglycidyl ether of 1,6-hexanediol. 1 for aliphatic polyhydric alcohols such as diglycidyl ether, triglycidyl ether of glycerin, triglycidyl ether of trimethylolpropane, diglycidyl ether of polyethylene glycol, diglycidyl ether of polypropylene glycol, ethylene glycol, propylene glycol, and glycerin. species or two
Examples include polyglycidyl ethers of polyether polyols obtained by adding more than one type of alkylene oxide, and diglycidyl esters of aliphatic long-chain dibasic acids. Further examples include epoxidized soybean oil, butyl epoxy stearate, octyl epoxy stearate, epoxidized linseed oil, and epoxidized polybutadiene. These aliphatic epoxy resins (a-3-3) having two or more epoxy groups in one molecule can be used alone or in combination of two or more types depending on the desired performance.

In the present invention, the energy ray-curable cationically polymerizable organic substance (a) can also contain a cationically polymerizable organic substance other than the epoxy resin. Cationically polymerizable organic substances other than epoxy resins are cationically polymerizable compounds that undergo a polymerization or crosslinking reaction by irradiation with active energy rays in the presence of an energy ray-sensitive cationic polymerization initiator (b), such as cyclic ether compounds, cyclic lactones, etc. compounds, cyclic acetal compounds, cyclic thioether compounds, spiro-orthoester compounds, vinyl compounds, etc.
It consists of two or more species or a mixture of two or more species. Specific examples include oxetane compounds such as trimethylene oxide, 3,3-dimethyloxetane, and 3,3-dichloromethyloxetane; oxolane compounds such as tetrahydrofuran and 2,3-dimethyltetrahydrofuran;
Cyclic acetal compounds such as trioxane, 1,3-dioxolane, 1,3,6-trioxanecyclooctane; cyclic lactone compounds such as β-propiolactone and ε-caprolactone; such as ethylene sulfide and thioepichlorohydrin Thiirane compounds such as 1,3-propyne sulfide, thietane compounds such as 3,3-dimethylthietane; ethylene glycol divinyl ether,
Alkyl vinyl ether, 3,4-dihydropyran-2
-vinyl ether compounds such as methyl (3,4-dihydropyran-2-carboxylate), triethylene glycol divinyl ether; spiroorthoester compounds obtained by reaction of epoxy compounds with lactones; such as vinylcyclohexane, isobutylene, polybutadiene ethylenically unsaturated compounds and derivatives of the above compounds. These cationic polymerizable compounds other than epoxy resins can be used alone or in combination of two or more kinds depending on the desired performance.

The energy ray-sensitive cationic polymerization initiator (b) used in the present invention is a compound capable of releasing a substance that initiates cationic polymerization upon irradiation with active energy rays, and particularly preferred ones are It is a group of double salts, which are onium salts that release Lewis acids. A typical onium salt is represented by the following general formula (1).

(R1aR2bR3cR4dZ)+m(MXn+m)−
m (1) (wherein the cation is an onium salt, Z is S, Se, Te, P, As, Sb, Bi, O, N, or a halogen atom, and R1, R2, R3, R4 are the same However, they are organic groups that may be different.Numbers a, b,
The sum of c and d is equal to the valence of Z. M is a metal or metalloid that is the central atom of the halide complex.
id), B, P, As, Al, Ca, In, Ti
, Zn, Sc, V, Cr, Mn, Co, etc. X is a halogen atom, m is the net charge of the halide complex ion, and n is the number of atoms in the halide complex ion. ) Anion of the above general formula (1) (MXn
Specific examples of +m)-m include tetrafluoroborate (BF4-), hexafluorophosphate (PF6-
), hexafluoroantimonate (SbF6-), hexafluoroarsenate (AsF6-), hexachloroantimonate (SbCl6-), and the like.

Furthermore, an anion represented by the general formula MXn(OH)- can also be used. Other anions include perchlorate ion (ClO4-), trifluoromethyl sulfite ion (CF3SO3-), fluorosulfonate ion (FSO3-), toluenesulfonate ion, trinitrobenzenesulfonate ion, etc. It will be done.

Among such onium salts, it is particularly effective to use aromatic onium salts as cationic polymerization initiators; Aromatic halonium salts described in JP-A-50-151977, JP-A-52-30899, JP-A-56-55420, etc.
Aromatic onium salts described in JP-A-55-125105, etc., aromatic onium salts described in JP-A-50-158698, etc., JP-A-56-8428, JP-A-56 -149402 Publication, JP-A-57-19
Oxosulfoxonium salts described in Publication No. 2429 etc.,
Preferred are aromatic diazonium salts described in Japanese Patent Publication No. 49-17040, aromatic onium salts described in Japanese Patent Application Laid-Open No. 61-190524, thiopyrylium salts described in US Pat. No. 4,139,655, and the like.

As the energy ray-sensitive cationic polymerization initiator other than the general formula (1), for example, an iron/arene complex or an aluminum complex may be used.

A photosensitizer such as benzophenone, benzoin isopropyl ether, or thioxanthone may be used in combination with the cationic polymerization initiator.

These cationic polymerization initiators can be used alone or in combination of two or more kinds depending on the desired performance.

The acrylate compound and methacrylate compound (hereinafter collectively referred to as "(meth)acrylate compound") (c) used in the present invention refers to a compound containing at least one (meth)acrylic group in one molecule. For example, epoxy (meth)acrylate, urethane (meth)acrylate, polyester (meth)
Examples include acrylates, polyether (meth)acrylates, and (meth)acrylic acid esters of alcohols.

Here, preferred epoxy (meth)acrylates include conventionally known aromatic epoxy resins, alicyclic epoxy resins, aliphatic epoxy resins, and (meth)acrylates.
It is a (meth)acrylate obtained by reacting with acrylic acid. Among these epoxy (meth)acrylates, particularly preferred are (meth)acrylates of aromatic epoxy resins, in which polyhydric phenols having at least one aromatic nucleus or polyglycidyl ethers of alkylene oxide adducts thereof, A (meth)acrylate obtained by reacting with (meth)acrylic acid, such as glycidyl ether obtained by reacting bisphenol A or its alkylene oxide adduct with epichlorohydrin, with (meth)acrylic acid. Examples include (meth)acrylate obtained by reacting an epoxy novolak resin with (meth)acrylic acid.

Preferred urethane (meth)acrylates are (meth)acrylates obtained by reacting one or more hydroxyl group-containing polyesters or hydroxyl group-containing polyethers with hydroxyl group-containing (meth)acrylic acid esters and isocyanates. These are acrylates and (meth)acrylates obtained by reacting hydroxyl group-containing (meth)acrylic acid esters with isocyanates. The hydroxyl group-containing polyester used here is preferably a hydroxyl group-containing polyester obtained by an esterification reaction between one or more aliphatic polyhydric alcohols and one or more polybasic acids. Examples of aliphatic polyhydric alcohols include 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, triethylene glycol, neopentyl glycol, polyethylene glycol, polypropylene glycol, and trimethylolpropane. , glycerin, pentaerythritol, and dipentaerythritol. Examples of polybasic acids include adipic acid, terephthalic acid, phthalic anhydride, and trimellitic acid. Preferred hydroxyl group-containing polyethers are hydroxyl group-containing polyethers obtained by adding one or more alkylene oxides to aliphatic polyhydric alcohols. 3-
Examples include butanediol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, triethylene glycol, neopentyl glycol, polyethylene glycol, polypropylene glycol, trimethylolpropane, glycerin, pentaerythritol, and dipentaerythritol. Examples of the alkylene oxide include ethylene oxide and propylene oxide. Preferred hydroxyl group-containing (meth)acrylic esters are hydroxyl group-containing (meth)acrylic esters obtained by an esterification reaction between an aliphatic polyhydric alcohol and (meth)acrylic acid,
Examples of aliphatic polyhydric alcohols include 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, triethylene glycol, neopentyl glycol, polyethylene glycol, polypropylene glycol, trimethylolpropane, Examples include glycerin, pentaerythritol, and dipentaerythritol.

Among such hydroxyl group-containing (meth)acrylic esters, hydroxyl group-containing (meth)acrylic esters obtained by the esterification reaction of an aliphatic dihydric alcohol and (meth)acrylic acid are particularly preferred, such as 2-
Hydroxyethyl (meth)acrylate is mentioned. As the isocyanate, compounds having at least one isocyanate group in the molecule are preferred, and divalent isocyanates such as toluylene diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate are particularly preferred.

[0028] Preferred polyester (meth)acrylates are polyester (meth)acrylates obtained by reacting hydroxyl group-containing polyesters with (meth)acrylic acid.
It is acrylate. Preferred hydroxyl group-containing polyesters used here are those produced by an esterification reaction between one or more aliphatic polyhydric alcohols and one or more monobasic acids, polybasic acids, and phenols. In the resulting hydroxyl group-containing polyester, examples of the aliphatic polyhydric alcohol include 1,3-butanediol,
1,4-butanediol, 1,6-hexanediol,
Examples include diethylene glycol, triethylene glycol, neopentyl glycol, polyethylene glycol, polypropylene glycol, trimethylolpropane, glycerin, pentaerythritol, and dipentaerythritol. Examples of monobasic acids include formic acid, acetic acid, butylcarboxylic acid, and benzoic acid. Examples of polybasic acids include adipic acid, terephthalic acid, phthalic anhydride, and trimellitic acid. Examples of phenols include phenol and P-nonylphenol.

Preferred polyether (meth)acrylates are polyether (meth)acrylates obtained by reacting hydroxyl group-containing polyethers with (meth)acrylic acid.
It is acrylate. Preferred hydroxyl group-containing polyethers used here are hydroxyl group-containing polyethers obtained by adding one or more alkylene oxides to an aliphatic polyhydric alcohol,
Examples of aliphatic polyhydric alcohols include 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, triethylene glycol, neopentyl glycol, polyethylene glycol, polypropylene glycol, trimethylolpropane, Examples include glycerin, pentaerythritol, and dipentaerythritol. Examples of the alkylene oxide include ethylene oxide and propylene oxide.

Preferred (meth)acrylic esters of alcohols include aromatic or aliphatic alcohols having at least one hydroxyl group in the molecule, and those obtained by reacting alkylene oxide adducts thereof with (meth)acrylic acid. It is a (meth)acrylate obtained by, for example,
2-ethylhexyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, isoamyl (meth)acrylate, lauryl (meth)acrylate, stearyl (
meth)acrylate, isooctyl(meth)acrylate, tetrahydrofurfuryl(meth)acrylate, isobornyl(meth)acrylate, benzyl(meth)acrylate, 1,3-butanediol di(meth)acrylate, 1,4-butanediol di( meth)acrylate, 1,6-hexanediol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene Examples include glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, and dipentaerythritol hexa(meth)acrylate.

These (meth)acrylate compounds are
They can be used alone or in combination of two or more kinds depending on the desired performance.

Radical polymerization initiator (d
) is a compound that can release a substance that initiates radical polymerization when irradiated with active energy rays, and includes acetophenone compounds, benzoin ether compounds,
Ketones such as benzyl compounds, benzophenone compounds, and thioxanthone compounds are preferred.

Examples of acetophenone compounds include 2,2-diethoxyacetophenone, 2-hydroxymethyl-1-phenylpropan-1-one, 4'-isopropyl-2-hydroxy-2-methyl-propiophenone, 2-hydroxy-2-methyl-propiophenone, P-dimethylaminoacetone, P-tert. -butyldichloroacetophenone, P-tert. -butyltrichloroacetophenone and P-azidobenzalacetophenone. Examples of benzoin ether compounds include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin-n-propyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, and benzoin isobutyl ether. Examples of the benzyl compound include benzyl, benzyl dimethyl ketal, benzyl-β-methoxyethyl acetal, and 1-hydroxycyclohexylphenyl ketone. Examples of benzophenone compounds include benzophenone, methyl O-benzoylbenzoate, Michler's ketone, 4,4'-bisdiethylaminobenzophenone, and 4,4'-dichlorobenzophenone. Examples of thioxanthone compounds include thioxanthone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2-chlorothioxanthone, and 2,4-diethylthioxanthone. These radical polymerization initiators (d)
These can be used alone or in combination of two or more kinds depending on the desired performance.

Next, the composition ratio of the energy ray-curable resin composition for casting of the present invention will be explained. The composition ratio will be explained in parts (parts by weight).

In the present invention, the composition ratio of the energy ray-curable cationic polymerizable organic substance (a) and the energy ray-sensitive cationic polymerization initiator (b) is as follows: Weight ratio with sensitive cationic polymerization initiator (b) is 98.0
It is preferably within the range of 0:2.00 to 99.99:0.01, more preferably 98.50:1.50 to
The energy ray-curable resin composition for casting is within the range of 99.10:0.10, particularly preferably within the range of 99.00:1.00 to 99.10:0.10. Shows particularly excellent properties.

Energy ray sensitive cationic polymerization initiator (
When the content of b) exceeds 2% by weight based on the total of the energy ray-curable cationic polymerizable organic substance (a) and the energy ray-sensitive cationic polymerization initiator (b),
Although the surface hardening speed becomes faster, the deep hardening property deteriorates, making it impossible to create a uniform cast product, which is undesirable because phenomena such as poor precision and cracking occur. Furthermore, the content of the energy ray-sensitive cationic polymerization initiator (b) is higher than that of the energy ray-curable cationically polymerizable organic substance (a).
If the amount is less than 0.01% by weight based on the total amount of cationic polymerization initiator (b) and energy ray-sensitive cationic polymerization initiator (b), the curing reaction will not proceed substantially, which is not preferable.

Epoxy resin having one epoxy group in one molecule (a-3-1), epoxy resin having both one or more cyclohexene oxide group and one or more alkylene oxide group in one molecule (a- 3-2), and the aliphatic epoxy resin (a-3-3) having at least two or more epoxy groups in one molecule act as a reactive diluent and a polymerization rate regulator, and are energy ray-curable cations. The polymerizable organic substance (a) is an epoxy resin (a-3-1) having one epoxy group in one molecule, or both one or more cyclohexene oxide group and one or more glycidyl group in one molecule. or an aliphatic epoxy resin (a-3-3) having at least two or more epoxy groups in one molecule. By containing 0.1 to 30 parts by weight, the viscosity of the composition of the present invention can be increased to 5000 at 25°C.
cps or less, the time for filling the resin into the casting mold is shortened, and workability is improved. Also, depending on the amount of epoxy resin (a-3) added, the curing speed of the composition due to active energy rays changes, but within the range of 0.1 to 30 parts by weight, uniform curing can be achieved and accurate three-dimensional objects can be formed. can be created.

If the content of the epoxy resin (a-3) in the energy beam-curable cationic polymerizable organic substance (a) is less than 0.1 part by weight, the dilution effect is poor and the viscosity of the composition is lower than 5000 cps. It is not possible to do so. If the amount exceeds 30 parts by weight, even if a three-dimensional model is created by irradiating energy rays, the curing properties will be poor and distortion or cracks will occur, which is not preferable.

Epoxy resin having one epoxy group in one molecule (a-3-1), epoxy resin having both one or more cyclohexene oxide group and one or more alkylene oxide group in one molecule (a- 3-2) and the aliphatic epoxy resin (a-3-3) having at least two or more epoxy groups in one molecule can be used alone or in combination of two or more depending on the desired performance. can be used.

The energy ray curable resin composition for casting of the present invention contains an energy ray curable cationic polymerizable organic substance (
a) is 30% by weight or more of an aromatic epoxy resin (a-1) having at least two or more epoxy groups in one molecule derived from bisphenols, and at least two or more cyclohexene oxide groups in one molecule. It contains 30% by weight or more of alicyclic epoxy resin (a-2) having By configuring the compounding ratio with the radiation-sensitive cationic polymerization initiator (b) to be 98.00:2.00 to 99.99:0.01 by weight, the curing sensitivity to energy rays is excellent and the curing Shrinkage (linear shrinkage rate) is 3% or less, deep curability is 10mm or more, liquid resin has good thermal stability, viscosity at 25°C is 5000cps or less, and the mechanical strength of the cured product and release from the mold are improved. It is possible to construct an extremely excellent energy ray-curable resin composition for casting with good properties.

In addition, when the energy ray-sensitive cationic polymerization initiator is an onium salt represented by the general formula (1), it can be used for casting with excellent stability under light such as fluorescent lamps or at temperatures below 100°C. An energy ray curable resin composition can be formed.

Transparent fine powders used in the present invention include fine powders of inorganic compounds such as glass powder, alumina powder, aluminosilicate powder, and silica powder, as well as polycarbonate, polymethyl methacrylate, polyacrylate, polyethylene, and polypropylene. , polyvinyl chloride, fine powder of transparent resin such as silicone resin, etc. Such a transparent fine powder is mixed with an energy ray-curable cationic polymerizable organic substance (a) and an energy ray-sensitive cationic polymerization initiator (
If the content is 0.1 to 10 parts by weight with respect to 100 parts by weight of the total amount of b), a three-dimensional object with very high precision can be obtained.

In the energy beam-curable resin composition for casting of the present invention, the (meth)acrylate compound (c) is replaced with the energy beam-curable cationically polymerizable organic substance (a).
The ratio of the total amount of the energy ray-sensitive cationic polymerization initiator (b) to the (meth)acrylate compound (c) is 60.
:40 to 98:2, and the radical polymerization initiator (d) is combined with the total amount of the energy ray-curable cationic polymerizable organic substance (a) and the energy ray-sensitive cationic polymerization initiator (b) (meth) Acrylate compound (c)
When the content is 0.01 to 4 parts by weight based on 100 parts by weight of the total amount, a composition particularly excellent in deep curability can be obtained.

Since the (meth)acrylate compound (c) has a large curing shrinkage, the (meth)acrylate compound (c)
c) If the ratio of the total amount of the energy beam-curable cationic polymerizable organic substance (a) and the energy beam-sensitive cationic polymerization initiator (b) to the (meth)acrylate compound is more than 60:40, the content of This is undesirable because the three-dimensional object is distorted or cracked. When the ratio is less than 98:2, there is virtually no difference in deep curability compared to when no (meth)acrylate (c) is contained.

The content of the radical polymerization initiator (d) is:
Total amount of energy beam-curable cationic polymerizable organic substance (a), energy beam-sensitive cationic polymerization initiator (b), and (meth)acrylate compound (c) 100
The content is preferably 0.01 to 4 parts by weight, more preferably 0.1 to 2 parts by weight. When the content of the radical polymerization initiator (d) is less than 0.01 part by weight, (meth) in the composition of the present invention
The acrylate compound cannot be reacted sufficiently,
If the amount exceeds 4 parts by weight, the deep curing properties will be significantly deteriorated and the cured product will be distorted, which is not preferable.

The energy-curable resin composition for casting of the present invention may optionally contain a heat-sensitive cationic polymerization initiator; a coloring agent such as a pigment or dye; an antifoaming agent, and a leveling agent, as long as the effects of the present invention are not impaired. Appropriate amounts of various resin additives such as additives, thickeners, flame retardants, antioxidants, and modifying resins can be used. As a heat-sensitive cationic polymerization initiator,
For example, JP-A-57-49613, JP-A-58-
Examples include aliphatic onium salts described in JP-A No. 37004.

The viscosity of the energy-curable resin composition for casting of the present invention is preferably 5000 cps at 25°C.
Below, it is more preferably 2000 cps or less. If the viscosity becomes too high, it takes a long time to fill the resin into the casting mold, which tends to impair workability.

[0048] Energy beam resin compositions generally shrink during curing, and are therefore required to have small shrinkage from the viewpoint of accuracy. The curing shrinkage rate of the composition of the present invention is preferably 3
% or less, more preferably 2% or less.

[0049] As a specific method for molding using the energy ray-curable resin composition for casting of the present invention, first, a concave mold for the three-dimensional model to be created is created using a material that can transmit energy rays such as ultraviolet rays. . Here, the material through which energy rays such as ultraviolet rays can pass is preferably a transparent resin such as polycarbonate, polymethyl methacrylate, polyacrylate, polyethylene, polypropylene, polyvinyl chloride, silicone resin, or a transparent inorganic material such as glass. The energy ray-curable resin composition for casting of the present invention is injected into this concave mold under normal pressure or reduced pressure, or by pressure injection, etc., and after degassing if necessary, energy is applied from the outside of the concave mold. The energy beam-curable resin composition for casting of the present invention injected into the concave mold is cured by irradiation with radiation to create a desired three-dimensional object.

The active energy rays used in curing the energy-curable resin composition for casting of the present invention include:
Ultraviolet rays, electron beams, X-rays, radiation, high frequencies, etc. can be used. Among these, 1800 to 5000
Ultraviolet rays having a wavelength of 100 Å are preferable, and as the light source, an ultraviolet laser, a mercury lamp, a xenon lamp, a sodium lamp, an alkali metal lamp, a metal halide lamp, etc. can be used. Particularly preferred light sources include lamps capable of irradiating ultraviolet rays, such as mercury lamps and metal halide lamps, which can efficiently cure the energy ray-curable resin composition for casting of the present invention and have a uniform cured product with little distortion. curing can be performed. An electron beam is also an effective light source.

The energy-curable resin composition for casting of the present invention is cured by a cationic polymerization reaction caused by active energy rays. By heating the resin composition to about 30 to 100° C. during energy ray irradiation, the crosslinking and curing reaction can be effectively promoted, and at the same time, the viscosity can be lowered and the time required for casting can be shortened. Further, by subjecting the three-dimensional model obtained by irradiating the energy beam to a heat treatment at a temperature of 40 to 100° C. or subjecting it to UV irradiation treatment using a mercury lamp or the like, it is also possible to obtain a shaped object with even better mechanical strength.

Specific fields of application of the energy-curable resin composition for casting of the present invention include various curved objects such as automobiles, electronic/electrical parts, furniture, architectural structures, toys, containers, castings, and dolls. Examples include models and processing.

[0053]

[Examples] Hereinafter, typical examples of the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to the following Examples. In the examples, "parts" means parts by weight.

Example 1 45 parts of bisphenol A diglycidyl ether as energy ray-curable cationically polymerizable organic substance (a);
3,4-epoxycyclohexylmethyl-3',4'-
40 parts of epoxycyclohexane carboxylate, 15 parts of vinylcyclohexene monooxide, energy ray-sensitive cationic polymerization initiator (b), bis-[4
-(Diphenylsulfonio)phenyl] 2 parts of sulfide bisdihexafluoroantimonate were thoroughly mixed to obtain an energy ray-curable resin composition for casting. Using transparent silicone resin, master model 2 in Figure 1 to Figure 2
A concave mold 3 was created. The energy beam-curable resin composition for casting was injected into the concave mold 3 while reducing the pressure using the vacuum pump 11 as shown in FIG. As shown in Figure 4, place this on the turntable 4 and rotate it at a rotation speed of 1 rotation/minute.
It was cured by irradiating ultraviolet rays with a 0w/cm high-pressure mercury lamp 5, 6, and a three-dimensional model 7 shown in FIG. 5 was created. The obtained three-dimensional model 7 was free from distortion, had extremely high precision, and had excellent mechanical strength. The time required to inject the energy beam curable resin composition for casting into the concave mold 3 under reduced pressure (hereinafter referred to as injection time) was 3 minutes, and the ultraviolet ray irradiation time was 5 minutes. The accuracy of the three-dimensional object obtained by measuring the vertical length L1 of the obtained three-dimensional model and the vertical length L2 of the master model, and using the following calculation formula [(L2-L1)/L2)] x 100 (hereinafter referred to as molding accuracy)
When calculated, it was found to be highly accurate at 1.1%. Also,
As shown in FIG. 6, a cylindrical glass container 8 with a diameter of 30 mm and a height of 50 mm is filled with the energy ray curable resin composition for casting, and the energy beam curable resin composition is heated at 80 W/cm from a position 15 cm above the container.
UV irradiation was performed for 3 minutes using a high-pressure mercury lamp 10, and the thickness L3 (hereinafter referred to as cure depth) of the cured resin 9 was measured and found to be 25 mm.

Example 2 Bisphenol A with 2 moles of ethylene oxide added as energy ray-curable cationically polymerizable organic substance (a)
30 parts of diglycidyl ether, 30 parts of bis(3,4-epoxycyclohexylmethyl)adipate, 20 parts of vinylcyclohexene dioxide, 10 parts of 1,4-butanediol diglycidyl ether, energy ray sensitive cationic polymerization initiator (b) , and 1 part of triphenylsulfonium hexafluoroantimonate were thoroughly mixed to obtain an energy ray-curable resin composition for casting of the present invention. When a three-dimensional model was created in the same manner as in Example 1, the three-dimensional model obtained was free of distortion, had extremely high accuracy, and had excellent mechanical strength. Since this resin composition has a low viscosity and is easy to handle, the injection time was as short as 1 minute, and the ultraviolet ray irradiation time was 5 minutes. Forming accuracy is 1.0
The accuracy was as high as %. The curing depth was measured in the same manner as in Example 1 and was found to be 31 mm.

Example 3 Energy beam-curable cationically polymerizable organic substances (a) were 20 parts of hydrogenated bisphenol A diglycidyl ether, 20 parts of bisphenol F diglycidyl ether, and 3,4-epoxycyclohexylmethyl-3',4. '
- 30 parts of epoxycyclohexane carboxylate, 1
, 10 parts of 6-hexanediol diglycidyl ether,
C12-13 Alcohol monoglycidyl ether 20
1 part of triphenylsulfonium hexafluoroantimonate as an energy ray-sensitive cationic polymerization initiator (b) was sufficiently mixed to obtain an energy ray-curable resin composition for casting of the present invention. When this resin composition was heated to 60°C and a three-dimensional model was created in the same manner as in Example 1, the three-dimensional model obtained was free of distortion, had extremely high accuracy, and had excellent mechanical strength. there were. Because it is heated to 60°C, the viscosity is very low at 30 cps and it is easy to handle, so the injection time is as short as 1 minute, and the reaction rate is accelerated by heating, so the UV irradiation time is 2 It was a very short time, about a minute. Forming accuracy is 1.5%
It was highly accurate. The curing depth was measured in the same manner as in Example 1 and was found to be 35 mm.

Example 4 45 parts of bisphenol A diglycidyl ether as energy ray-curable cationically polymerizable organic substance (a);
3,4-epoxycyclohexylmethyl-3',4'-
40 parts of epoxycyclohexane carboxylate, 15 parts of vinylcyclohexene monooxide, energy ray-sensitive cationic polymerization initiator (b), bis-[4
-(Diphenylsulfonio)phenyl] 2 parts of sulfide bisdihexafluoroantimonate and 10 parts of glass beads with a diameter of 20 μm as a transparent fine powder were thoroughly mixed to obtain the energy ray-curable resin composition for casting of the present invention. Ta. When a three-dimensional model was created in the same manner as in Example 1, the three-dimensional model obtained was free of distortion, had extremely high accuracy, and had excellent mechanical strength. The injection time was 5 minutes, and the ultraviolet irradiation time was 5 minutes. Since this composition contained glass beads, the molding accuracy was very high at 0.5%. The curing depth was measured in the same manner as in Example 1 and was found to be 19 mm.

Example 5 40 parts of bisphenol A diglycidyl ether as energy ray-curable cationically polymerizable organic substance (a);
3,4-epoxycyclohexylmethyl-3',4'-
40 parts of epoxycyclohexane carboxylate, 10 parts of vinylcyclohexene monooxide, energy ray-sensitive cationic polymerization initiator (b), bis-[4
2 parts of -(diphenylsulfonio)phenyl]sulfide bisdihexafluoroantimonate, 10 parts of bisphenol A epoxy acrylate as the acrylate compound (c), 1 part as the radical polymerization initiator (d)
One part of hydroxycyclohexyl phenyl ketone was thoroughly mixed to obtain the energy ray-curable resin composition for casting of the present invention. When a three-dimensional model was created in the same manner as in Example 1, the three-dimensional model obtained was free of distortion, had extremely high accuracy, and had excellent mechanical strength. The injection time was 3 minutes, and the ultraviolet irradiation time was 5 minutes. The molding accuracy was high at 1.5%. When the curing depth was measured in the same manner as in Example 1, this composition had a high deep curability of 49 mm because it contained an acrylate compound.

Comparative Example 1 A photocurable resin composition was obtained by thoroughly mixing 70 parts of dipentaerythritol hexaacrylate, 30 parts of trimethylolpropane triacrylate, and 3 parts of benzophenone. When a three-dimensional model was created in the same manner as in Example 1, the resulting three-dimensional model had large cracks due to curing shrinkage. In addition, internal stress was generated due to curing shrinkage, resulting in poor mechanical strength. The injection time was 5 minutes, and the ultraviolet irradiation time was 5 minutes. The molding accuracy could not be measured because the created model was damaged. An attempt was made to measure the cure depth using the same procedure as in Example 1, but it was impossible to measure because the cured product was severely distorted and cracked.

Comparative Example 2 70 parts of bisphenol A epoxy acrylate, 30 parts of trimethylolpropane triacrylate, and 3 parts of benzyl dimethyl ketal were thoroughly mixed to obtain a photocurable resin composition. When a three-dimensional model was created in the same manner as in Example 1, the resulting three-dimensional model suffered from large distortions due to curing shrinkage, was extremely inaccurate, and had cracks in some areas. In addition, mechanical strength was poor because internal stress was generated due to curing shrinkage. The injection time was 5 minutes, and the ultraviolet irradiation time was 5 minutes. The molding accuracy was very poor at 4.5%. An attempt was made to measure the cure depth using the same procedure as in Example 1, but it was impossible to measure because the cured product was severely distorted and cracked.

[0061]

Effects of the invention: The effects of the present invention are that the curing sensitivity to energy rays is excellent, the curing shrinkage (linear shrinkage rate) is 3% or less, the deep curability is 10 mm or more, the liquid resin has good thermal stability, and the curing Good mechanical strength and mold releasability,
The present invention provides an extremely excellent energy ray curable resin composition for casting.

[0062] When the energy ray-sensitive cationic polymerization initiator (b) is an onium salt represented by the above general formula (1), in addition to the above properties, it can be used under fluorescent lamp light or at temperatures below 100°C. It is possible to construct an energy ray-curable resin composition for casting that has excellent stability under the conditions. The energy ray curable resin composition for casting of the present invention comprises a transparent fine powder, an energy ray curable cationically polymerizable organic substance (a) and an energy ray sensitive cationic polymerization initiator (
If the content is 0.1 to 10 parts by weight with respect to 100 parts by weight of the total amount of b), a three-dimensional object with very high precision can be obtained.

The energy ray curable resin composition for casting of the present invention comprises a (meth)acrylate compound (c), an energy ray curable cationically polymerizable organic substance (a) and an energy ray sensitive cationic polymerization initiator (b). ) and (
The ratio with meth)acrylate compound (c) is 60:40
~98:2, and a radical polymerization initiator (
d) an energy beam-curable cationic polymerizable organic substance (
a) and an energy ray-sensitive cationic polymerization initiator (b)
and (meth)acrylate compound (c) total amount 10
When containing 0.01 to 2 parts by weight relative to 0 parts by weight,
In particular, a composition with excellent deep curability can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a master model used for molding. In the figure, L2 indicates the length in the vertical direction.

FIG. 2 is a schematic diagram of a silicone resin concave mold.

FIG. 3 is a schematic diagram illustrating a resin injection operation.

FIG. 4a is a schematic diagram showing a resin curing operation, and b and c are schematic diagrams of a high-pressure mercury lamp.

FIG. 5 is a schematic diagram of a molded three-dimensional model. In the diagram, L
1 indicates the length in the vertical direction.

FIG. 6a is a schematic diagram illustrating a method for measuring cure depth. b
is a schematic diagram of a high-pressure mercury lamp. In the figure, L3 indicates the hardening depth.

[Explanation of symbols]

1... Energy beam curable resin composition for casting 2... Master model 3... Concave mold 4... Turntable 5... High pressure mercury lamp 6... High pressure mercury lamp 7... Three-dimensional model 8... Glass container 9... Cured resin 10... High pressure mercury Lamp 11...vacuum pump

Claims (7)

[Claims] Claim 1: At least 30% by weight of an aromatic epoxy resin (a-1) derived from bisphenols and having at least two epoxy groups per molecule as an essential component, at least two epoxy groups per molecule. 30% by weight or more of the above alicyclic epoxy resin (a-2) having a cyclohexene oxide group, an epoxy resin (a-3-1) having one epoxy group in one molecule, or one epoxy resin in one molecule. Epoxy resin (a-3-2) having both the above cyclohexene oxide group and one or more alkylene oxide group, or 1
Any one or more epoxy resin (a-3-3) of aliphatic epoxy resins having two or more epoxy groups in the molecule (
an energy beam-curable cationically polymerizable organic substance (a) containing 0.1 to 30% by weight of a-3); and an energy-beam-sensitive cationic polymerization initiator (b); The weight ratio of the substance (a) and the energy ray-sensitive cationic polymerization initiator (b) is 98.00:2.00 to 99.99:0.0.
1. An energy beam-curable resin composition for casting, characterized in that: Claim 2: Energy ray-sensitive cationic polymerization initiator (
The energy beam-curable resin composition for casting according to claim 1, wherein b) is an onium salt represented by the following general formula. (R1aR2bR3cR4dZ)+m(MXn+m)-
m (wherein the cation is an onium salt, Z is S, Se,
Te, P, As, Sb, Bi, O, N, or a halogen atom, and R1, R2, R3, and R4 are organic groups that may be the same or different. The sum of numbers a, b, c, and d is equal to the valence of Z. M is a metal or metalloid that is the central atom of the halide complex. X is a halogen atom, m is the net charge of the halide complex ion, and n is the number of atoms in the halide complex ion. ) 3. Transparent fine powder is added in an amount of 0.1 to 10 parts by weight per 100 parts by weight of the total amount of the energy beam-curable cationic polymerizable organic substance (a) and the energy beam-sensitive cationic polymerization initiator (b). The energy beam-curable resin composition for casting according to claim 1 or 2, characterized in that it contains part by weight. 4. At least 30% by weight of an aromatic epoxy resin (a-1) derived from bisphenols and having at least two epoxy groups per molecule as an essential component, at least two epoxy groups per molecule. 30% by weight or more of the above alicyclic epoxy resin (a-2) having a cyclohexene oxide group, an epoxy resin (a-3-1) having one epoxy group in one molecule, or one epoxy resin in one molecule. Epoxy resin (a-3-2) having both the above cyclohexene oxide group and one or more alkylene oxide group, or 1
Any one or more epoxy resin (a-3-3) of aliphatic epoxy resins having two or more epoxy groups in the molecule (
an energy beam-curable cationic polymerizable organic substance (a) containing 0.1 to 30% by weight of a-3), an energy beam-sensitive cationic polymerization initiator (b), an acrylate compound or methacrylate compound (c), and a radical It contains a polymerization initiator (d), and the blending ratio of the energy ray-curable cationic polymerizable organic substance (a) and the energy ray-sensitive cationic polymerization initiator (b) is 98.
00:2.00 to 99.99:0.01, and the total amount of the energy ray-curable cationic polymerizable organic substance (a) and the energy ray-sensitive cationic polymerization initiator (b) and the acrylate compound or methacrylate compound (c )
The weight ratio of the radical polymerization initiator (d) to the energy beam-curable cationic polymerizable organic substance (a) and the energy beam-sensitive cationic polymerization initiator (b) is in the range of 60:40 to 98:2. An energy beam-curable resin composition for casting, characterized in that it contains 0.01 to 4 parts by weight per 100 parts by weight of the total amount of the acrylate compound or methacrylate compound (c). Claim 5: Energy ray-sensitive cationic polymerization initiator (
The energy beam-curable resin composition for casting according to claim 4, wherein b) is an onium salt represented by the following general formula. (R1aR2bR3cR4dZ)+m(MXn+m)-
m (wherein the cation is an onium salt, Z is S, Se,
Te, P, As, Sb, Bi, O, N, or a halogen atom, and R1, R2, R3, and R4 are organic groups that may be the same or different. The sum of numbers a, b, c, and d is equal to the valence of Z. M is a metal or metalloid that is the central atom of the halide complex. X is a halogen atom, m is the net charge of the halide complex ion, and n is the number of atoms in the halide complex ion. ) 6. Transparent fine powder is subjected to radical polymerization with an energy beam-curable cationic polymerizable organic substance (a), an energy beam-sensitive cationic polymerization initiator (b), an acrylate compound or a methacrylate compound (c), 0.1 to 100 parts by weight of the total amount of initiator (d)
Claim 4 or 5, characterized in that it contains 10 parts by weight.
The energy beam curable resin composition for casting described above. 7. The energy wire for casting according to any one of claims 1 to 6, characterized in that the viscosity at 25° C. is 5000 cps or less and the curing shrinkage rate (linear shrinkage) is 3% or less. Curable resin composition.