JPH09235338A - Curable liquid resin composition for forming optical part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition containing an epoxy (meth)acrylate and a specific compound, having low viscosity and extremely small curing shrinkage in the curing with heat and/or radiation and useful for lens for optical instruments, etc. SOLUTION: This resin composition contains (A) an epoxy (meth)acrylate having a bisphenol skeleton (e.g. epoxy (meth)acrylate) and (B) a compound of the formula (R<1> to R<4> are each H or CH3 ; (n) is 1-5). The component B is produced e.g. by reacting p-cumylphenol, etc., with ethylene oxide, etc., and reacting the obtained compound with (meth)acrylic acid. Preferably, the amount of the component A is 25-55wt.% in the total composition and that of the component B is 50-200 pts.wt. based on 100 pts.wt. of the component A.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a liquid curable resin composition used for producing an optical member. More specifically, a liquid curable resin suitable for manufacturing lenses for optical equipment such as hybrid lenses used for cameras and VTR cameras for photography, film lenses used for liquid crystal displays, Fresnel lenses used for projection TVs, etc. It relates to a composition.

[0002]

2. Description of the Related Art A lens for optical equipment is required to be lightweight, thin and have excellent optical characteristics, and it is necessary to remove aberrations in order to obtain clear image quality. High and excellent light dispersion characteristics (small Abbe number)
Materials need to be used. Further, spherical aberration can be reduced by using an aspherical lens, but since inorganic glass is difficult to process as a material used for manufacturing the lens, a liquid curable resin that is cured by heat and / or radiation is developed. Is required. To date, introduction of a compound having a halogen atom other than fluorine, particularly bromine, or an aromatic urethane acrylate into the liquid curable resin has been studied in order to achieve a high refractive index (JP-A-1-302201). Japanese Patent Laid-Open No. 3-2
96513, Japanese Unexamined Patent Publication No. 4-216814, Japanese Unexamined Patent Publication No. 5-117348, Japanese Unexamined Patent Publication No. 5-255463.
JP-A-5-287040, JP-A-5-3
No. 10871).

[0003]

However, in the development of a liquid curable resin, it is extremely difficult to improve the refractive index and the light dispersion characteristic while maintaining many characteristics required for an optical material. For example, the introduction of bromine or chlorine causes color deterioration due to heat or radiation during molding of the liquid curable resin,
There are problems such as gas generation due to dehalogenation, and there are severe restrictions in terms of cost. Further, the introduction of the aromatic urethane acrylate has a drawback that the surface hardness of the lens is lowered and it causes deterioration such as yellowing and deterioration of mechanical properties due to long-term light irradiation.

Further, since the liquid curable resin causes shrinkage due to heat curing and / or radiation curing, it is necessary that the shrinkage during curing is small and that the viscosity is low in order to improve workability. Furthermore, in order to impart sufficient mechanical properties to the lens itself, a resin with high surface hardness and tensile modulus and high toughness is desired, and at the same time, its optical properties and mechanical properties should not change over a long period of time. is required. So far, there is no resin that can solve all the above-mentioned required characteristics, and there has been a long-felt demand for the development of a resin that satisfies all the above-mentioned characteristics at the same time. Therefore, an object of the present invention is to provide a liquid curing liquid for producing an optical member which has a low viscosity, has extremely small shrinkage upon curing by heat and / or radiation, has high transparency and refractive index of a cured product, and has good mechanical properties. PROBLEM TO BE SOLVED: To provide a liquid curable resin composition suitable for a resin composition, particularly a lens for optical equipment.

[0005]

Means for Solving the Problems In the present invention, (A) an epoxy (meth) acrylate having a bisphenol skeleton (hereinafter, also referred to as “compound (A)”) and (B) the following formula (1):

[0006]

Embedded image

(Wherein R ¹ , R ² , R ³ and R ⁴ independently of one another are H or CH ₃ and n is a number from 1 to 5) (hereinafter referred to as "compound" (B) "is also contained. A liquid curable resin composition for producing an optical member is provided.

The compound (A) used in the present invention is an epoxy (meth) acrylate having a bisphenol skeleton, which is obtained by reacting an epoxy compound having a bisphenol skeleton with (meth) acrylic acid or a (meth) acrylic acid derivative. It is the compound obtained by this.
As the compound (A), about 0.7 to 1.5 chemical equivalents of (meth) acrylic acid or (meth) acrylic acid derivative relative to 1 chemical equivalent of the epoxy group of the epoxy compound, particularly preferably about 0.1. A compound obtained by reacting at a ratio of 9 to 1.1 chemical equivalent is preferably used.

Examples of the compound (A) include epoxy (meth) acrylate obtained by adding (meth) acrylic acid to diglycidyl ether of bisphenol A, and (meth) acrylic acid added to diglycidyl ether of bisphenol F. Epoxy (meth) acrylate, epoxy (meth) acrylate obtained by adding (meth) acrylic acid to diglycidyl ether of bisphenol S, epoxy (meth) obtained by adding (meth) acrylic acid to diglycidyl ether of brominated bisphenol A Acrylate,
Epoxy (meth) acrylate obtained by adding (meth) acrylic acid to diglycidyl ether of brominated bisphenol F, epoxy (meth) acrylate obtained by adding (meth) acrylic acid to diglycidyl ether of brominated bisphenol S, etc. be able to.

Of these, an epoxy (meth) acrylate obtained by adding (meth) acrylic acid to diglycidyl ether of bisphenol A and an epoxy (meth) acrylate obtained by adding (meth) acrylic acid to diglycidyl ether of bisphenol F Etc. are preferred. The compound (A) preferably has a number average molecular weight of 400 to 2000, and particularly preferably 450 to 1000. When the number average molecular weight of these compounds (A) is less than 400, the reactivity of the composition tends to be low, and it may be difficult to obtain a cured product having sufficient tensile elastic modulus and surface hardness. On the other hand, when it is 2000 or more, the viscosity of the composition is increased and it becomes difficult to handle it, so that good productivity cannot be obtained, and at the same time, inconvenience such as deterioration of moldability may occur.

The compound (A) is incorporated in the entire composition in an amount of preferably 10 to 70% by weight, more preferably 20 to 60% by weight, and particularly preferably 25 to 55% by weight. 10
If it is less than 10% by weight, the cured product tends to have a low tensile elastic modulus and a low surface hardness, which tends to cause inconveniences such as reduced curability. On the other hand, if the amount exceeds 70% by weight, the viscosity of the composition increases, which makes handling difficult and, at the same time, tends to cause inconveniences such as large shrinkage during curing. In addition, the toughness of the cured product may decrease, making it difficult to withstand bending and the like, which may cause cracking.

The compound (B) used in the present invention is represented by the above general formula (1). The compound (B) is, for example, p
-An average of 1 to 5 chemical equivalents of ethylene oxide or propylene oxide is reacted with 1 chemical equivalent of phenolic hydroxyl group such as cumylphenol and p-benzylphenol, and the resulting compound is further reacted with (meth) acrylic acid. You can get it. As the compound (B) represented by the general formula (1), (meth) acrylate of p-cumylphenol reacted with ethylene oxide is particularly preferable, and Aronix TO-1210 (manufactured by Toagosei Kagaku Co., Ltd.) is commercially available. Can be used.

The compound (B) used in the present invention is preferably 20 to 500 relative to 100 parts by weight of the compound (A).
Parts by weight, more preferably 30 to 300 parts by weight, and particularly preferably 50 to 200 parts by weight. If it is less than 20 parts by weight, shrinkage at the time of curing may be large, or the toughness of the cured product may be deteriorated to make it difficult to withstand bending or the like, and cracking may occur. On the other hand, if it exceeds 500 parts by weight, the cured product tends to be soft, and the tensile elastic modulus and surface hardness tend to decrease.

In the present invention, a monomer having a (meth) acryloyl group or a vinyl group (hereinafter referred to as "unsaturated monomer") other than the above-mentioned compound (A) and compound (B) may be used as an optional component. it can. As such an unsaturated monomer, a monofunctional monomer and a polyfunctional monomer can be used, and examples of the monofunctional monomer include (meth) acrylamide and (meth).
Acryloylmorpholine, 7-amino-3,7-dimethyloctyl (meth) acrylate, isobutoxymethyl (meth) acrylamide, isobornyloxyethyl (meth) acrylate, isobornyl (meth) acrylate, 2-ethylhexyl (meth) acrylate , Ethyldiethylene glycol (meth) acrylate, t-octyl (meth) acrylamide, diacetone (meth) acrylamide, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, lauryl (meth) acrylate, dicyclopentadiene (meth) acrylate , Dicyclopentenyloxyethyl (meth) acrylate, dicyclopentenyl (meth)
Acrylate, N, N-dimethyl (meth) acrylamide tetrachlorophenyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, 2- (2,4,
6-trichlorophenoxy) ethyl (meth) acrylate, 2,4,6-tribromophenyl (meth) acrylate, 2- (2,4,6-tribromophenoxy) ethyl (meth) acrylate, 2-hydroxyethyl (meth) )
Acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate,
Phenoxyethyl (meth) acrylate, butoxyethyl (meth) acrylate, pentachlorophenyl (meth) acrylate, pentabromophenyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, bornyl (meth) acrylate , Methyltriethylenediglycol (meth) acrylate, the following formulas (2) to (4)

[0015]

Embedded image

(In the formula, R ⁵ represents a hydrogen atom or a methyl group, R ⁶ represents an alkylene group having 2 to ⁶ carbon atoms, preferably 2 to 4 carbon atoms, R ⁷ represents a hydrogen atom or 1 to 12 carbon atoms,
It preferably represents an alkyl group having 1 to 9 and R ⁸ has 2 carbon atoms.
To 8 and preferably 2 to 5 alkylene groups and a plurality of R
⁹ independently of each other represents a hydrogen atom or a methyl group,
r represents an integer of 0 to 12, preferably 1 to 8, and q represents 1
~ 8, preferably an integer of 1 to 4) (meth) acryloyl group-containing monomers such as compounds; vinyl group-containing monomers such as N-vinylcaprolactam, N-vinylpyrrolidone, N-vinylcarbazole and the like. You can

Of these, (meth) acryloylmorpholine, isobornyl (meth) acrylate, N
-Vinylcarbazole, N-vinylcaprolactam, N
-Vinylpyrrolidone, phenoxyethyl (meth) acrylate, 2- (2,4,6-tribromophenoxy) ethyl (meth) acrylate and the like are preferable. Commercially available products of these monofunctional monomers include, for example, Aronix M-1.
11, M-113, M-117 (above, manufactured by Toagosei Co., Ltd.), KAYARAD TC110S, R-629,
R-644 (above, Nippon Kayaku Co., Ltd.), Viscoat 3
700 (manufactured by Osaka Organic Chemical Industry Co., Ltd.) and the like can be used.

Examples of the polyfunctional monomer include ethylene glycol di (meth) acrylate, triethylene glycol diacrylate, tetraethylene glycol di (meth) acrylate, tricyclodecanediyldimethylene di (meth) acrylate, tris (2). -Hydroxyethyl) isocyanurate di (meth) acrylate, tris (2-hydroxyethyl) isocyanurate tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolpropane trioxyethyl (meth) acrylate, tripropylene glycol Di (meth) acrylate, neopentyl glycol di (meth) acrylate, bisphenol A diglycidyl ether both-end (meth) acrylic acid adduct,
1,4-butanediol di (meth) acrylate, 1.6
Hexanediol di (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, polyester di (meth) acrylate, polyethylene glycol di (meth) acrylate, dipentaerythritol hexa (meth) acrylate, ε Of hexa (meth) acrylate of dipentaerythritol to which ring-capping of caprolactone was added, dimethylolpropane tetra (meth) acrylate, di (meth) acrylate of bisphenol A reacted with ethylene oxide, and bisphenol A reacted with propylene oxide (Meth) acryloyl group-containing monomers such as di (meth) acrylate may be mentioned.

Of these, tricyclodecanediyldimethylene di (meth) acrylate, tris (2-hydroxyethyl) isocyanurate tri (meth) acrylate, and di (meth) acrylate of bisphenol A reacted with ethylene oxide are particularly preferable.

Commercially available products of these polyfunctional monomers include, for example, UPIMER UV, SA1002 (above, Mitsubishi Chemical Co., Ltd.), Viscoat 700 (above, made by Osaka Organic Chemical Industry Co., Ltd.), KAYARAD R-604, DP.
CA-60, DPCA-30, DPCA-120, HX
-620, D-310, D-330 (all manufactured by Nippon Kayaku Co., Ltd.), Aronix M-210, M-215, M
-315, M-325 (above, Toagosei Co., Ltd. make) etc. can be used.

The above unsaturated monomers can be used alone or in combination of two or more, and usually, the compound (A) is used.
0 to 500 parts by weight, preferably 1 to 100 parts by weight
0 to 200 parts by weight can be blended. If it exceeds 500 parts by weight, shrinkage of the cured product at the time of curing tends to be large, and a problem such as a decrease in refractive index is likely to occur.

The composition of the present invention is cured by heat and / or radiation. Here, radiation means, for example, infrared rays, visible rays, ultraviolet rays and X-rays, electron beams, α rays, β
Rays, ionizing radiation such as gamma rays.

When the composition of the present invention is cured with visible light and / or ultraviolet light, for example, a polymerization initiator is usually used. As the polymerization initiator, a photopolymerization initiator and, if necessary, a photosensitizer are used. As such a photopolymerization initiator, any one may be used as long as it can be decomposed by light irradiation to generate radicals to initiate polymerization, for example, acetophenone, acetophenone benzyl ketal, anthraquinone, 1- (4-isopropylphenyl). -2-Hydroxy-2-methylpropane-
1-one, carbazole, xanthone, 4-chlorobenzophenone, 4,4'-diaminobenzophenone, 1,1
-Dimethoxydeoxybenzoin, 3,3'-dimethyl-4-methoxybenzophenone, thioxanthone, diethylthioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, 1- (4-dodecylphenyl) -2-hydroxy-2-methylpropane- 1-
On, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propan-1-one, triphenylamine, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, benzyldimethylketal, 1-hydroxy Cyclohexyl phenyl ketone, 2
-Hydroxy-2-methyl-1-phenylpropane-1
-One, fluorenone, fluorene, benzaldehyde, benzoin ethyl ether, benzoin propyl ether, benzophenone, Michler's ketone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one, 3-methylacetophenone 3,3 ', 4,4'-tetra (t-butylperoxycarbonyl) benzophenone (hereinafter referred to as "BTTB") and a combination of BTTB with xanthene, thioxanthene, coumarin, ketocoumarin, and the like. Of these, especially benzyl dimethyl ketal, 1
-Hydroxycyclohexyl phenyl ketone, 2,4,6
-Trimethylbenzoyldiphenylphosphine oxide, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one and the like are preferable. These commercially available products include Irgacure 184,
651, 500, 907, 369, 784, 2959
(Above, made by Ciba Geigy), Lucirin TPO
(Above, manufactured by BASF), Darocur 1116, 11
73 (above, made by Merck), Yubecryl P36 (above, U
CB) and the like. Further, as the photosensitizer, triethylamine, diethylamine, N-methyldiethanolamine, ethanolamine, 4-dimethylaminobenzoic acid, methyl 4-dimethylaminobenzoate,
There are ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate and the like, and commercially available products include Yubecryl P102, 103, 104 and 105 (above, UCB
Manufactured) and the like.

The content of the photopolymerization initiator in the entire composition is preferably 0.01 to 10% by weight, more preferably 0.5 to 7% by weight, and particularly preferably 1 to 5% by weight. . If it exceeds 10% by weight, the curing properties of the composition, the mechanical properties and optical properties of the cured product may be adversely affected, and if it is less than 0.01% by weight, the curing rate may decrease. Further, when the composition of the present invention is heat-cured, an ordinary radical polymerization initiator can be used. Preferred radical polymerization initiators include, for example, peroxides and azo compounds, and specific examples include benzoyl peroxide, t-butyl-peroxybenzoate, azobisisobutyronitrile and the like. it can.

Further, as additives to be added as necessary, for example, antioxidants, colorants, ultraviolet absorbers, light stabilizers, silane coupling agents, thermal polymerization inhibitors, leveling agents, surfactants, preservatives Examples include stabilizers, plasticizers, lubricants, solvents, inorganic fillers, organic fillers, fillers, antioxidants, wettability improvers, and coating surface improvers. Commercially available antioxidants include Irganox 1010, 1
035, 1076, 1222 (above, made by Ciba Geigy)
The commercially available products of the ultraviolet absorber include Tin.
uvin P, 234, 320, 326, 327, 32
8, 213 (above, made by Ciba Geigy), Sumisor
b 110, 130, 140, 220, 250, 30
0, 320, 340, 350, 400 (above, manufactured by Sumitomo Chemical Co., Ltd.) and the like, and commercially available light stabilizers include Tinuvin 292, 144, 622LD.
(Above, made by Ciba Geigy), Sanor LS-770, 7
65, 292, 2626, 1114, 744 (above, manufactured by Sankyo Kasei Co., Ltd.) and the like, and examples of the silane coupling agent include γ-aminopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, and γ-.
Methacryloxypropyltrimethoxysilane, as commercially available products SH6062, SZ6030 (above, Toray
Dow Corning Silicone), KBE903, K
BM803 (above, manufactured by Shin-Etsu Silicone Co., Ltd.) and the like can be mentioned, and as a commercial product of the antiaging agent, Antigen
e W, S, P, 3C, 6C, RD-G, FR, AW
(Above, manufactured by Sumitomo Chemical Co., Ltd.) and the like.

In the composition of the present invention, other additives such as epoxy resin, urethane (meth) acrylate,
Polymerizable compounds such as vinyl ether, propenyl ether, maleic acid derivative, polyamide, polyimide, polyamideimide, polyurethane, polybutadiene, chloroprene, polyether, polyester, pentadiene derivative, styrene / butadiene / styrene block copolymer, styrene / ethylene / butene Polymers or oligomers such as / styrene block copolymer, styrene / isoprene / styrene block copolymer, petroleum resin, xylene resin, ketone resin, fluorine-based oligomer, silicone-based oligomer, and polysulfide-based oligomer can also be blended.

The composition of the present invention can be produced by mixing the above-mentioned components by a conventional method. The viscosity of the composition of the present invention thus prepared is usually 100 to 2
2,000 cps / 25 ° C, preferably 500 to 10.0
It is 00 cps / 25 ° C. By curing the composition of the present invention with heat and / or radiation, the cured product generally has a tensile modulus at 23 ° C. of 1 to 250 kg / mm.
You can get ^two . The preferable refractive index (25 ° C.) of the cured product at that time is 1.55 or more, particularly 1.5.
It is 6 or more, and the cure shrinkage is preferably 6% or less, particularly preferably 5% or less.

[0028]

EXAMPLES The present invention will be described below in more detail with reference to examples, but the present invention is not limited to these examples. In the following, "parts" means "parts by weight".

Examples 1 to 3 and Comparative Examples 1 to 4 Each component having the composition shown in Table 1 was charged into a reaction vessel equipped with a stirrer and stirred for 3 hours while controlling the liquid temperature at 50 to 60 ° C. to cure the liquid. A resin composition was obtained. The urethane acrylate oligomer used in Comparative Examples 1 and 2 was prepared according to the following synthetic method.

Method for synthesizing urethane acrylate oligomer In a reaction vessel equipped with a stirrer, 37.70 parts of isophorone diisocyanate, 42.50 parts of polyester diol (terephthalic acid / methylpentanediol copolymer) having a number average molecular weight of 500, and polymerization inhibition 2,6-di-as an agent
0.02 part of t-butyl-p-cresol was charged. Then, these were cooled with ice until the liquid temperature became 10 ° C. or lower while stirring them. After the liquid temperature became 10 ° C or lower, 0.08 part of dibutyltin dilaurate was added, 19.70 parts of hydroxyethyl acrylate was added dropwise, and the liquid temperature was adjusted to 10-2.
The mixture was stirred for 2 hours while controlling at 0 ° C. After that, liquid temperature 5
Stirring is continued at 0 to 60 ° C for 3 hours, and when the residual isocyanate is 0.1% by weight or less, the stirring is finished,
A urethane acrylate oligomer having a number average molecular weight of 1180 was obtained. The urethane acrylate oligomer obtained by this method is designated as UA-1.

Evaluation Method A test piece was prepared by the following method using the liquid curable resin composition obtained in the above example, and the viscosity, refractive index, and
The tensile modulus, pencil hardness, cure shrinkage and bending resistance were evaluated.

Viscosity measurement: According to JIS K7117, the viscosity at 25 ° C. was measured using a rotational viscometer. Preparation of test pieces: A liquid curable resin composition was applied on a glass plate to a thickness of about 200 μm by using an applicator bar of 15 mil, and irradiated with ultraviolet rays of 1.0 J / cm ^{2 in} an air atmosphere, to form a cured film. Got Then, the cured film was peeled off from the glass plate and conditioned at 23 ° C. and 50% relative humidity for 24 hours to prepare a test piece. Refractive Index Measurement: The refractive index at 25 ° C. of the test piece prepared above was measured using an Abbe refractometer. Tensile elastic modulus measurement: 23 ° C according to JIS K7113
The tensile modulus of elasticity of the above test piece was measured. However,
The tensile speed was 1 mm / min, and the tensile modulus was calculated from the tensile stress at a strain of 2.5%.

Pencil hardness measurement: According to JIS K5400, the pencil hardness of the above test piece was measured using a pencil scratch tester. Curing shrinkage measurement: The liquid density of the liquid curable resin composition and the cured product density were measured using the above test pieces, and the curing shrinkage ratio of the cured product was calculated using the following formula. Curing shrinkage rate (%) = [1- (liquid density / cured product density)] ×
100

Bending test The test piece prepared above was wrapped around a cylinder having a diameter of 5 mm,
The breakage of the test piece was observed. The observation result is no damage: ○,
Damage: Shown in Table 1 as x.

[0035]

[Table 1]

In Table 1, component (A): acrylate of bisphenol A diglycidyl ether. Mn = 510 (B) component: p-cumylphenol acrylate reacted with ethylene oxide. Mn = 310 Monomer (1): Diacrylate of bisphenol A reacted with ethylene oxide. Mn = 512 Monomer (2): phenoxyethyl acrylate. Mn
= 192 Monomer (3): 2- (2,4,6-tribromophenoxy) ethyl acrylate. Mn = 429 Monomer (4): acryloylmorpholine. Mn = 1
41 Photopolymerization initiator: 1-hydroxycyclohexyl phenyl ketone (* Mn represents a number average molecular weight).

[0037]

EFFECTS OF THE INVENTION The liquid curable resin composition of the present invention has a low viscosity, a very small curing shrinkage upon curing by heat and / or radiation, and a large tensile elastic modulus, surface hardness and toughness. Gives a cured product with a high refractive index,
It is suitable for making optical members such as lenses for optical devices.

The preferred embodiments of the present invention will be described below. 1. A liquid curable resin composition for producing an optical member, which comprises (A) an epoxy (meth) acrylate having a bisphenol skeleton and (B) a compound represented by the above formula (1). 2. 10 to 10 parts of the above epoxy (meth) acrylate (A)
The liquid curable resin composition as described in 1 above, which is contained at 70% by weight. 3. The liquid curable resin composition as described in 1 above, which contains the compound (B) in an amount of 20 to 500 parts by weight per 100 parts by weight of the compound (A). 4. The liquid curable resin composition according to 1 above, which further contains an unsaturated monomer in addition to the components (A) and (B), and the amount thereof is 500 parts by weight or less per 100 parts by weight of the compound (A). . 5. The liquid curable resin composition as described in 1 above, which has a tensile elastic modulus after curing of 1 to 250 Kg / mm ² .

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Takeshi Watanabe 2--11-24 Tsukiji, Chuo-ku, Tokyo Inside Nippon Gosei Rubber Co., Ltd. (72) Takashi Ukaji 2-11-24 Tsukiji, Chuo-ku, Tokyo No. Japan Synthetic Rubber Co., Ltd.

Claims (1)

[Claims] 1. An epoxy (meth) acrylate having a bisphenol skeleton (A) and (B) the following formula (1): (In the formula, R ¹ , R ² , R ³ and R ⁴ are independently of each other H
Alternatively, a liquid curable resin composition for producing an optical member, comprising a compound represented by CH ₃ and n is a number of 1 to 5).