JPH11349658A - Curable composition and optical material obtained by using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a curable composition which can give an optical material having a low specific gravity, excellent optical properties including a high refractive index and a high Abbe's number, and improved handleability at a near room temperature by mixing a specified polythiol with a compound copolymerizable therewith. SOLUTION: A cyanuric halide of formula I (wherein X is Cl, Br, or I) is reacted with 3-30 mol, per mol of the cyanuric halide, of a dithiol at -20 to 150 deg.C to obtain a polythiol of formula II (wherein (n) is 0-5). 5-90 wt.% of this polythiol is mixed with 10-95 wt.% least one copolymerizable compound selected among a polyisocyanate compound, a polyisothiocyanate compound, an isocyanato-containing isothiocyanate compound, a monomer having a polymerizable unsaturated bond, an epoxy compound, an epithio compound, and a monomer having a plurality of thiol groups and being other than the polythiol of formula II.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a curable composition and an optical material obtained using the same. More specifically, it is useful as a raw material for optical materials such as plastic lenses for spectacles, Fresnel lenses, lenticure lenses, optical disc substrates, plastic optical fibers, prism sheets for LCDs, light guide plates, diffusion sheets, paints, adhesives, and sealants. The present invention relates to a curable composition and an optical material obtained using the same.

[0002]

2. Description of the Related Art Conventionally, polystyrene resins, polymethyl methacrylate resins, polycarbonate resins, diethylene glycol diallyl carbonate resins, and the like are widely used as resins for optical materials because they are lighter and easier to handle than glass. ing.

[0003] However, these resins for optical materials have drawbacks in that they have a low refractive index, a large birefringence and a large dispersing ability, and are inferior in heat resistance and impact resistance.

[0004] Particularly, diethylene glycol diallyl carbonate resin used as a lens material has a low refractive index of 1.50, and therefore, when used as a lens, the edge thickness and the center thickness become large. Disadvantageously, and the weight is increased.

In recent years, a method for improving the refractive index among these drawbacks has been studied. For example, Japanese Patent Publication No. 5-4404 proposes a resin in which halogen is introduced into an aromatic ring. However, the resin is
Although the refractive index is as high as 1.60, the specific gravity is as large as 1.37. Therefore, when used for a plastic lens, for example, there is a disadvantage that the lightness required for the lens is not satisfied.

Further, Japanese Patent Publication No. 4-15249 and Japanese Patent Application Laid-Open No. 60-199016 disclose a resin obtained by copolymerizing an isocyanate compound and a polythiol. However, although the resin has a large refractive index of 1.60, the polymerization temperature during the production is relatively low, and the polymerization rate is high, so that it is difficult to control the heat during the polymerization. is there.

Further, Japanese Patent Application Laid-Open No. 3-54226 discloses that
Bis (4-methacryloylthiophenyl) sulfide,
A resin obtained by copolymerizing styrene and polythiol is disclosed. However, the resin has a large refractive index of 1.65, but a low Abbe number of about 26,
There is a disadvantage that the dispersibility is large.

[0008]

The present invention has been made in view of the above prior art, and provides a resin having a low specific gravity, a high refractive index, a high Abbe number, and excellent optical properties. An object of the present invention is to provide a curable composition having excellent handleability at around room temperature.

Another object of the present invention is to provide an optical material obtained by curing the curable composition.

[0010]

That is, the gist of the present invention is as follows: (1) General formula (I):

[0011]

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(Wherein n represents an integer of 0 to 5 which may be the same or different) and 5 to 90% by weight of a polythiol and 10 to 95% by weight of a compound copolymerizable with the polythiol. A curable composition comprising: (2) a compound copolymerizable with polythiol has a polyisocyanate compound, a polyisothiocyanate compound, an isothiocyanate compound having an isocyanate group, and a polymerizable unsaturated bond The curable composition according to the above (1), which is at least one selected from the group consisting of a monomer, an epoxy compound, an epithio compound and a monomer having a plurality of thiol groups other than the polythiol represented by the general formula (I), And (3) an optical material obtained by curing the curable composition according to (1) or (2).

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION As described above, the curable composition of the present invention has the general formula (I):

[0014]

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(Wherein n represents an integer of 0 to 5 which may be the same or different), and 5 to 90% by weight of a polythiol and 10 to 95% by weight of a compound copolymerizable with the polythiol. It contains.

In the present invention, since the polythiol represented by the general formula (I) is a liquid at around room temperature, it is easy to handle at a low temperature, and is a compound excellent in workability and safety. .

In the polythiol represented by the general formula (I), n is 0 to 0, which may be the same or different.
Indicates an integer of 5. When n is an integer of 6 or more, its synthesis is difficult and not practical.

The polythiol represented by the general formula (I) includes, for example, 2,4,6-trimercapto-1,3,3
5-triazine, 2,4-dimercapto-6- (2-mercaptoethylthio) -1,3,5-triazine, 2,
6-dimercapto-4- (2-mercaptoethylthio)
-1,3,5-triazine, 4,6-dimercapto-2
-(2-mercaptoethylthio) -1,3,5-triazine, 2,4,6-tri (2-mercaptoethylthio)
-1,3,5-triazine, 2,4-di (2-mercaptoethylthio) -6-mercapto-1,3,5-triazine, 2,6-di (2-mercaptoethylthio) -4-
Mercapto-1,3,5-triazine, 4,6-di (2
-Mercaptoethylthio) -2-mercapto-1,3,3
5-triazine, 2,4,6-tri (5-mercapto-
3-thiapentathio) -1,3,5-triazine, 2,
4-di (5-mercapto-3-thiapentathio) -6
Mercapto-1,3,5-triazine, 2,6-di (5
-Mercapto-3-thiapentathio) -4-mercapto-1,3,5-triazine, 4,6-di (5-mercapto-3-thiapentathio) -2-mercapto-1,3,3
5-triazine, 2,4-di (5-mercapto-3-thiapentathio) -6- (2-mercaptoethylthio)-
1,3,5-triazine, 2,6-di (5-mercapto-3-thiapentathio) -4- (2-mercaptoethylthio) -1,3,5-triazine, 4,6-di (5-mercapto -3-thiapentathio) -2- (2-mercaptoethylthio) -1,3,5-triazine, 4- (5-
(Mercapto-3-thiapentathio) -2,6-dimercapto-1,3,5-triazine, 2-mercapto-4-
(5-mercapto-3-thiapentathio) -6- (2-
Mercaptoethylthio) -1,3,5-triazine,
2,4,6-tri (8-mercapto-3,6-thiapentathio) -1,3,5-triazine, 2,4,6-tri (11-mercapto-3,6,9-trithiaundecathio) -1,3,5-triazine, 2,4,6-tri (1
4-mercapto-3,6,9,12-tetrathiatetradecathio) -1,3,5-triazine, 2- (5-mercapto-3-thiapentathio) -4,6-di (8-mercapto-3) , 6-Dithiaoctathio) -1,3,5-triazine, 2,4-di (5-mercapto-3-thiapentathio) -6- (8-mercapto-3,6-dithiaoctathio) -1,3,5-triazine , 2- (2-mercaptoethylthio) -4- (5-mercapto-3-thiapentathio) -6- (8-mercapto-3,6-dithiaoctathio) -1,3,5-triazine, 4,6-di (1
1-mercapto-3,6,9-trithiaundecathio)
-2- (5-mercapto-3-thiapentathio) -1,
3,5-triazine, 2- (5-mercapto-3-thiapentathio) -4- (8-mercapto-3,6-dithiaoctathio) -6- (11-mercapto-3,6,9-
Trithia undecathio) -1,3,5-triazine, 2
-(2-Mercaptoethylthio) -4- (5-mercapto-3-thiapentathio) -6- (11-mercapto-
3,6,9-trithiaundecathio) -1,3,5-triazine, 2,4-di (5-mercapto-3-thiapentathio) -6- (11-mercapto-3,6,9-trithiaun Decathio) -1,3,5-triazine, 2,4
-Di (5-mercapto-3-thiapentathio) -6-
(14-mercapto-3,6,9,12-tetrathiatetradecathio) -1,3,5-triazine, 2- (5-
Mercapto-3-thiapentathio) -4- (8-mercapto-3,6-dithiaoctathio) -6- (14-mercapto-3,6,9,12-tetrathiatetradecathio) -1,3,5-triazine , 2- (5-mercapto-3-thiapentathio) -4- (11-mercapto-
3,6,9-Trithiaundecathio) -6- (14-mercapto-3,6,9,12-tetrathiatetradecathio) -1,3,5-triazine, 4,6-di (14- Mercapto-3,6,9,12-tetrathiatetradecathio) -2- (5-mercapto-3-thiapentathio)-
1,3,5-triazine and the like. These polythiols can be used alone or in combination of two or more.

Among these, 2,4,6-tri (2
-Mercaptoethylthio) -1,3,5-triazine,
2,4,6-tri (5-mercapto-3-thiapentathio) -1,3,5-triazine, 2,6-di (5-mercapto-3-thiapentathio) -4- (2-mercaptoethylthio)- 1,3,5-triazine, 2,4-di (5-mercapto-3-thiapentathio) -6- (2-
Mercaptoethylthio) -1,3,5-triazine,
4,6-di (5-mercapto-3-thiapentathio)-
2- (2-mercaptoethylthio) -1,3,5-triazine, 2,4,6-tri (8-mercapto-3,6-
Thiapentathio) -1,3,5-triazine, 2,4
6-tri (11-mercapto-3,6,9-trithiaundecatio) -1,3,5-triazine, 2,4,6-
Tri (14-mercapto-3,6,9,12-tetrathiatetradecathio) -1,3,5-triazine, 2-
(5-mercapto-3-thiapentathio) -4,6-di (8-mercapto-3,6-dithiaoctathio) -1,
3,5-Triazine and the like are preferable, and 2,4,6-tri (2-mercaptoethylthio) -1,3,5-triazine, 2,4,6-tri (5-mercapto-3-thipentathio) -1 , 3,5-triazine, 2,6-di (5-
Mercapto-3-thiapentathio) -4- (2-mercaptoethylthio) -1,3,5-triazine, 2,4-
Di (5-mercapto-3-thiapentathio) -6- (2
-Mercaptoethylthio) -1,3,5-triazine,
4,6-di (5-mercapto-3-thiapentathio)-
2- (2-mercaptoethylthio) -1,3,5-triazine and the like are more preferred.

The method for producing the polythiol is not particularly limited. For example, in the case where n is an integer of 1 to 5 in the polythiol represented by the general formula (I),
In the presence of a base, the compound of the general formula (II):

[0021]

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(Wherein X represents a chlorine atom, a bromine atom or an iodine atom), and a method of reacting a cyanuric halide and dithiol.

Specifically, examples of the usable base include tertiary amines such as trimethylamine, triethylamine, tripropylamine, tributylamine, N, N-dimethylaniline, and sodium hydroxide and potassium hydroxide. Examples thereof include metal hydroxides, metal carbonates such as sodium carbonate and potassium carbonate, and metal alcoholates such as sodium methylate, sodium ethylate, and potassium tert-butylate. The amount of the base used is represented by the general formula (II)
With respect to the cyanuric halide represented by
Usually, it is desired to be 3 to 6 times, preferably 3 to 4 times.

Examples of the dithiol include 1,2-ethanedithiol, bis (2-mercaptoethyl) sulfide,
1,8-dimercapto 3,6-dithiaoctane, 1,
Examples thereof include 11-dimercapto-3,6,9-trithiaundecane and 1,14-dimercapto-3,6,9,12-tetrathiatetradecane. These dithiols are not limited to single use, and may be used in combination of several kinds in order to obtain a target polythiol. The amount of the dithiol used is usually 3 to 30 times, preferably 6 to 21 times, the molar ratio of the cyanuric halide represented by the general formula (II).

The reaction temperature is desirably -20 to 150 ° C, preferably -10 to 100 ° C.

In this reaction, excess dithiol doubles as a reaction solvent, but an organic solvent may be used. Examples of the organic solvent include hydrocarbons such as toluene, xylene, hexane, and cyclohexane; methylene chloride;
Halogenated hydrocarbons such as 1,2-dichloroethane, monochlorobenzene, o-dichlorobenzene and the like can be mentioned. In this case, good results are often obtained when a quaternary ammonium salt such as tetra-n-butylammonium bromide is used as the phase transfer catalyst.

In the general formula (I), the polythiol in which n is 0 is obtained by reacting a cyanuric halide represented by the general formula (II) with thiourea to form an isothiuronium salt, and then converting the isothiuronium salt to a base. By hydrolysis.

Further, in the general formula (I), n is 1 to
The polythiol represented by the general formula (II)
Can be obtained by reacting a cyanuric halide represented by the following formula with a mercapto alcohol to form a polyol, reacting this with thiourea to form an isothiuronium salt, and then hydrolyzing the isothiuronium salt with a base.

As mercapto alcohol, for example,
1-hydroxy-2-mercaptoethane, 1-hydroxy-5-mercapto-3-thiapentane, 1-hydroxy-8-mercapto-3,6-dithiaoctane, 1-hydroxy-11-mercapto-3,6,9-trithiaundecane, 1-hydroxy- 14-mercapto-3,
6,9,12-tetrathiatetradecane and the like.

More specifically, the amount of thiourea used in producing the isothiuronium salt is usually in a molar ratio with respect to the cyanuric halide represented by the general formula (II).
It is desirably 3 to 9 times, preferably 3 to 6 times.

The reaction temperature for producing the isothiuronium salt is preferably from 20 to 120 ° C., and more preferably from 40 to 110 ° C.

Examples of the organic solvent usable in this reaction include hydrocarbons such as toluene, xylene, hexane and cyclohexane, and halogens such as methylene chloride, 1,2-dichloroethane, monochlorobenzene and o-dichlorobenzene. Hydrocarbons and the like. In this case, good results are often obtained when a quaternary ammonium salt such as tetra-n-butylammonium bromide is used as the phase transfer catalyst. The reaction can also be carried out using water as a solvent.

As the base used in the hydrolysis of the isothiuronium salt, similar to the above, tertiary amines, metal hydroxides, metal carbonates and metal alcoholates, as well as primary bases such as ammonia, monoethylamine, monobutylamine, etc. Amine, dimethylamine, diethylamine,
Secondary amines such as dibutylamine are exemplified. The amount of the base used is usually 3 to 18 times, preferably 3 to 9 times, the equivalent ratio to the cyanuric halide represented by the general formula (II).

The temperature during the hydrolysis is from 20 to 120 ° C.
Preferably it is 30-110 degreeC.

Examples of the organic solvent used for the hydrolysis include hydrocarbons and halogenated hydrocarbons used for producing the isothiuronium salt.

Typical examples of the compound copolymerizable with the polythiol represented by the general formula (I) include polyisocyanate compounds, polyisothiocyanate compounds, isothiocyanate compounds having an isocyanate group, and polymerizable compounds. Examples include at least one selected from the group consisting of monomers having unsaturated bonds, epoxy compounds, epithio compounds, and monomers having a plurality of thiol groups other than the polythiol represented by the general formula (I). The compounds copolymerizable with the polythiol can be used alone or in combination of two or more.

Specific examples of the polyisocyanate compound include, for example, aliphatic polyisocyanate, alicyclic polyisocyanate, aromatic polyisocyanate, and sulfur-containing polyisocyanate.

Representative examples of the aliphatic polyisocyanate include, for example, ethylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate,
Hexamethylene diisocyanate, m-xylylene diisocyanate, bis (isocyanatoethyl) benzene, bis (isocyanatopropyl) benzene, bis (isocyanatobutyl) benzene, bis (isocyanatomethyl) naphthalene and the like. Can be used alone or in combination of two or more. Among these, hexamethylene diisocyanate, m-xylylene diisocyanate and bis (isocyanatoethyl) benzene, especially m-xylylene diisocyanate, provide an optical material having a high refractive index, and are economical. From the viewpoint of being excellent, they can be suitably used in the present invention.

Representative examples of alicyclic polyisocyanates include, for example, isophorone diisocyanate, cyclohexane diisocyanate, methylcyclohexane diisocyanate, bis (isocyanatomethyl) cyclohexane, dicyclohexylmethane diisocyanate,
Examples include 2′-dimethyldicyclohexylmethane diisocyanate and dicyclohexyldimethylmethane diisocyanate, and these can be used alone or in combination of two or more. Of these, isophorone diisocyanate, cyclohexane diisocyanate and bis (isocyanatomethyl) cyclohexane are:
From the viewpoint of providing an optical material having a high refractive index and a high Abbe number, it can be suitably used in the present invention.

Representative examples of aromatic polyisocyanates include, for example, tolylene diisocyanate, phenylene diisocyanate, dimethyl phenylene diisocyanate, ethyl phenylene diisocyanate, diethyl phenylene diisocyanate, benzene triisocyanate, benzene triisocyanate, trimethyl Benzene triisocyanate, naphthalene diisocyanate, biphenyl diisocyanate,
4,4′-diphenylmethane diisocyanate, toluidine diisocyanate and the like can be mentioned, and these can be used alone or in combination of two or more. Among these, tolylene diisocyanate and 4,4'-
Diphenylmethane diisocyanate can be suitably used in the present invention from the viewpoint of providing an optical material having a high refractive index and being excellent in economy.

Representative examples of the sulfur-containing polyisocyanate include, for example, thiodiethyldiisocyanate, dithiodiethyldiisocyanate, thiodipropyldiisocyanate, dithiodipropyldiisocyanate, and diphenylsulfide-4,4'-. Diisocyanate, diphenyl sulfide-2,4'-diisocyanate, bis (4-
Isocyanatomethylbenzene) sulfide, 1,4-
Dithiane-2,5-diisocyanate, diphenyldisulfide-4,4'-diisocyanate and the like;
These can be used alone or in combination of two or more. Among these, diphenyl sulfide-
4,4′-diisocyanate can be suitably used in the present invention from the viewpoint of providing an optical material having a high refractive index.

Specific examples of the polyisothiocyanate compound include, for example, aliphatic polyisothiocyanate,
Examples include alicyclic polyisothiocyanate, aromatic polyisothiocyanate, aralkyl polyisothiocyanate, and sulfur-containing polyisothiocyanate.

Representative examples of the aliphatic polyisothiocyanate or the alicyclic polyisothiocyanate include, for example,
Aliphatic polyisothiocyanates such as 1,2-diisothiocyanatoethane, 1,3-diisothiocyanatopropane and 1,4-diisothiocyanatobutane; alicyclic polyisothiocyanates such as cyclohexanediisothiocyanate Ossinate and the like can be used alone or in combination of two or more.

Representative examples of aromatic polyisothiocyanate or aralkyl polyisothiocyanate include, for example, 1,2-diisothiocyanatobenzene, 1,3-
Diisothiocyanatobenzene, 1,4-diisothiocyanatobenzene, 2,4-diisothiocyanatotoluene, 2,5-diisothiocyanato-m-xylene,
Aromatic polyisothiocyanates such as 4,4'-diisothiocyanate 1,1'-biphenyl and 1,1'-methylenebis (4-isothiocyanatobenzene); p-phenylenediisopropylidene diisothiocyanate And the like, and these can be used alone or in combination of two or more. Among these, 1,2-diisothiocyanatobenzene, 1,3-diisothiocyanatobenzene, and 1,4-diisothiocyanatobenzene are preferred from the viewpoint of providing an optical material having a high refractive index. It can be suitably used in the above.

Representative examples of the sulfur-containing polyisothiocyanate include, for example, thiobis (2-isothiocyanatoethane), dithiobis (2-isothiocyanatoethane), thiobis (3-isothiocyanatopropane),
Examples thereof include thiobis (4-isothiocyanatobenzene) and sulfonylbis (4-isothiocyanatobenzene), and these can be used alone or in combination of two or more.

Specific examples of the isothiocyanate compound having an isocyanate group include aliphatic isothiocyanate compounds, alicyclic isothiocyanate compounds, aromatic isothiocyanate compounds, and sulfur-containing isothiocyanate compounds. Is mentioned.

Representative examples of the aliphatic isothiocyanate compound and the alicyclic isothiocyanate compound include, for example, 1-isocyanate-3-isothiocyanate propane, 1-isocyanate-6-isothiocyanate hexane and the like. Aliphatic isothiocyanate compounds; alicyclic isothiocyanate compounds such as 1-isocyanato-4-isothiocyanatocyclohexane, etc., and these can be used alone or in combination of two or more.

Typical examples of the aromatic isothiocyanate compound include 1-isocyanato-4-isothiocyanatobenzene, 4-methyl-3-isocyanato-1-isothiocyanatobenzene, and the like. Can be used alone or in combination of two or more.

Representative examples of the sulfur-containing isothiocyanate compound include, for example, 4-isocyanate-4'-isothiocyanatodiphenyl sulfide, and these can be used alone or as a mixture of two or more. it can.

Specific examples of the monomer having a polymerizable unsaturated bond include, for example, an aromatic vinyl compound, an alicyclic vinyl compound, (meth) acrylic acid, a monofunctional (meth) acrylic acid derivative, and a polyfunctional (meth) acrylate. ) Acrylic acid derivatives, vinyl sulfide compounds and the like. Here, “(meth) acryl” means both “acryl” and “methacryl” (the same applies hereinafter). These monomers having a polymerizable unsaturated bond can be used alone or in combination of two or more.

Representative examples of the aromatic vinyl compound include, for example, styrene, α-methylstyrene, vinyltoluene, chlorostyrene, bromostyrene, chloromethylstyrene, methoxystyrene, butylthiostyrene, divinylbenzene and the like. Can be used alone or in combination of two or more. Among them, styrene and divinylbenzene can be suitably used in the present invention.

Representative examples of the alicyclic vinyl compound include, for example, cyclohexene, 4-vinylcyclohexene,
Examples thereof include 1,5-cyclooctadiene and 5-vinylbicyclo [2,2,1] hept-2-ene, and these can be used alone or as a mixture of two or more.

Representative examples of monofunctional (meth) acrylic acid derivatives include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, dodecyl (meth) acrylate, octadecyl (Meth) acrylate, cyclohexyl (meth) acrylate, methylcyclohexyl (meth) acrylate, 2-ethylhexyl (meth)
Acrylate, bornyl (meth) acrylate, isobornyl (meth) acrylate, adamantyl (meth) acrylate, phenyl (meth) acrylate, benzyl (meth) acrylate, 1-naphthyl (meth) acrylate, chlorophenyl (meth) acrylate, bromophenyl (meth) A) acrylate, tribromophenyl (meth) acrylate, methoxyphenyl (meth) acrylate, cyanophenyl (meth) acrylate, chloromethyl (meth) acrylate, bromoethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxy Propyl (meth) acrylate,
(Meth) acrylic acid polyethylene glycol ester,
N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, glycidyl (meth) acrylate, phenylthio (meth) acrylate, and the like may be used alone or as a mixture of two or more. Can be. Of these, methyl (meth) acrylate, cyclohexyl (meth) acrylate, phenyl (meth) acrylate, glycidyl (meth) acrylate and phenylthio (meth) acrylate
From the viewpoint of providing an optical material having a high Abbe number and a low specific gravity and being excellent in economy, it can be suitably used in the present invention.

Representative examples of the polyfunctional (meth) acrylic acid derivative include, for example, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (methacrylate), and tetraethylene glycol di (meth) acrylate. , Propylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, 1,3-butanediol di (meth) acrylate, 1,4-butanediol di (meth) acrylate 1,5-pentanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, Data pentaerythritol tri (meth)
Polyol poly (meth) acrylates such as acrylate, pentaerythritol tetra (meth) acrylate;
Bis (4-methacryloylthiophenyl) sulfide,
Polythiol poly (meth) such as ethanediol dimethacrylate, bis [(2-methacryloylthio) ethyl]
Acrylates and the like can be mentioned, and these can be used alone or in combination of two or more. Among these, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, bis (4 -Methacryloylthiophenyl) sulfide and bis [(2-methacryloylthio) ethyl] sulfide can be suitably used in the present invention from the viewpoint that they provide an optical material having a high Abbe number and a low specific gravity and are excellent in economic efficiency. Things.

Representative examples of the vinyl sulfide compound include, for example, ethyl vinyl sulfide, n-propyl vinyl sulfide, isobutyl vinyl sulfide, t-butyl vinyl sulfide, n-amyl vinyl sulfide,
Isoamyl vinyl sulfide, cyclohexyl vinyl sulfide, 2-ethylhexyl vinyl sulfide, n-
Octadecyl vinyl sulfide, dodecyl vinyl sulfide, propenyl sulfide propylene carbonate,
1,2-divinylthioethane, 1,3-divinylthiopropane, 1,4-divinylthiobutane, 1,6-divinylthiohexane, bis (2-vinylthioethyl) sulfide, phenylvinylsulfide, bis (4- Vinylthiophenyl) sulfide, bis (4-vinylthiomethylphenyl) sulfide, 2,4′-bis (vinylthiomethyl) sulfide, 2,4,4′-tri (vinylthiomethyl) phenyl sulfide, and the like, These can be used alone or in combination of two or more. Among them, bis (2-vinylthioethyl) sulfide, phenylvinyl sulfide, bis (4-vinylthiophenyl) sulfide, and bis (4-vinylthiomethylphenyl) sulfide, particularly bis (4-vinylthiomethylphenyl) sulfide
Vinyl thiophenyl) sulfide, bis (4-vinyl thiomethyl phenyl) sulfide, 2,4'-bis (vinyl thiomethyl) phenyl sulfide, and 2,4,4'-tri (vinyl thiomethyl) phenyl sulfide have high refraction. From the viewpoint of providing an optical material having a refractive index, it can be suitably used in the present invention.

Examples of the epoxy compound include monomers having an epoxy group and oligomers having an epoxy group.

Representative examples of the monomer having an epoxy group and the oligomer having an epoxy group include, for example, monofunctional glycidyl ether, polyfunctional aliphatic glycidyl ether, polyfunctional aromatic glycidyl ether, polyfunctional glycidyl thioether, and glycidyl ester. And alicyclic epoxy resins. These epoxy compounds can be used alone or in combination of two or more.

Representative examples of the monofunctional glycidyl ether include, for example, allyl glycidyl ether, butyl glycidyl ether, phenyl glycidyl ether, 2-ethylhexyl glycidyl ether, sec-butylphenyl glycidyl ether, tert-butylphenyl glycidyl ether, 2-methyl Octyl glycidyl ether and the like can be mentioned, and these can be used alone or in combination of two or more.

Representative examples of the polyfunctional aliphatic glycidyl ether include, for example, 1,6-hexanediol glycidyl ether, trimethylolpropane triglycidyl ether, neopentyl glycol diglycidyl ether, glycerol diglycidyl ether, and glycerol triglycidyl ether. , Ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, and the like, and these can be used alone or in combination of two or more. Among these, ethylene glycol diglycidyl ether can be suitably used in the present invention from the viewpoint of providing an optical material having a high Abbe number and being excellent in economic efficiency.

Representative examples of the polyfunctional aromatic glycidyl ether include, for example, bisphenol A glycidyl ether, bisphenol F glycidyl ether, brominated bisphenol A glycidyl ether, biphenol glycidyl ether, tetramethyl biphenol glycidyl ether, resorcin glycidyl ether, hydroquinone glycidyl Ether, dihydroxynaphthalene glycidyl ether, bisphenol novolak resin glycidyl ether, phenol novolak resin glycidyl ether, cresol novolak resin glycidyl ether, dicyclopentadiene phenol resin glycidyl ether, terpene phenol resin glycidyl ether,
Naphthol novolak resin glycidyl ether and the like can be mentioned, and these can be used alone or in combination of two or more. Among these, bisphenol A glycidyl ether and brominated bisphenol A glycidyl ether provide optical materials with a high refractive index,
In addition, from the viewpoint of excellent economy, it can be suitably used in the present invention.

As a typical example of the polyfunctional glycidyl thioether, bis [4- (2,3-epoxypropylthio)
Phenyl] sulfide, 1,4-di (2,3-epoxypropylthio) benzene, and the like, and these can be used alone or as a mixture of two or more.

Representative examples of glycidyl esters include, for example, glycidyl (meth) acrylate, diglycidyl phthalate, diglycidyl hexahydrophthalate, diglycidyl tetrahydrophthalate, dimethyldiglycidyl hexahydrophthalate, and the like. Two or more kinds can be used as a mixture. Of these, glycidyl (meth) acrylate is
From the viewpoint of providing an optical material having a high Abbe number and being excellent in economical efficiency, it can be suitably used in the present invention.

Representative examples of alicyclic epoxy resins include, for example, 3,4-epoxycyclohexylmethyl-3,4
-Epoxycyclohexanecarboxylate, 3,4-
Epoxycyclohexylethyl-3,4-epoxycyclohexanecarboxylate, vinylcyclohexene dioxide, allylcyclohexene dioxide, 3,4-
Epoxy-4-methylcyclohexyl-2-propylene oxide, 2- (3,4-epoxycyclohexyl-
5,5-spiro-3,4-epoxy) cyclohexane-
m-dioxane, bis (3,4-epoxycyclohexyl) adipate, bis (3,4-epoxycyclohexylmethyl) adipate, bis (3,4-epoxycyclohexyl) ether, bis (3,4-epoxycyclohexylmethyl) ether, Bis (3,4-epoxycyclohexyl) diethylsiloxane and the like can be mentioned, and these can be used alone or in combination of two or more. Among these, 3,4-epoxycyclohexylethyl-3,4-epoxycyclohexanecarboxylate can be suitably used in the present invention from the viewpoint that it provides an optical material having a high Abbe number and is excellent in economy. Things.

Representative examples of epithio compounds include, for example, bis [4- (2,3-epithiopropylthiophenyl) sulfide, bis [4- (2,3-epithiopropylthio) -3-methylphenyl] Sulfide, bis [4
-(2,3-epithiopropylthio) -3-methylphenyl] sulfide, bis [4- (2,3-epithiopropylthio) -3,5-dimethylphenyl] sulfide, and the like, which are used alone Or a mixture of two or more. Among these epithio compounds, bis [4- (2,3-epithiopropylthio) phenyl] sulfide can be suitably used in the present invention from the viewpoint of providing an optical material having a high refractive index. is there.

Specific examples of the monomer having a plurality of thiol groups other than the polythiol represented by the general formula (I) include, for example, aliphatic polythiol, aliphatic sulfide,
Aromatic dithiols and the like can be mentioned. These can be used alone or in combination of two or more.

Representative examples of the aliphatic polythiol include, for example, 1,2-ethanedithiol, 1,3-propanedithiol, 1,4-butanedithiol, 1,6-hexanedithiol, 1,8-octanedithiol, 1,2-
Cyclohexanedithiol, ethylene glycol bisthioglycolate, ethylene glycol bisthiopropionate, butanediol bisthioglycolate, butanediol bisthiopropionate, trimethylolpropane tristhioglycolate, trimethylolpropane tristhiopropionate, Pentaerythritol tetrakisthioglycolate, pentaerythritol tetrakisthiopropionate, tris (2-mercaptoethyl) isocyanurate, tris (3-mercaptopropyl) isocyanurate, 4,4′-bis (mercaptomethyl) phenyl sulfide, 4,4′-bis (4-mercapto-2-thiabutyl) phenyl sulfide, 4,
4'-bis (7-mercapto-2,5-dithiaheptyl) phenyl sulfide, 2,4'-bis (mercaptomethyl) phenyl sulfide, 2,4'-bis (4-mercapto-2-thiabutyl) phenyl sulfide, ,
4'-bis (7-mercapto-2,5-dithiabutyl)
Phenyl sulfide, 2,4,4′-tri (mercaptomethyl) phenyl sulfide, 2,4,4′-tri (4
-Mercapto-2-thiabutyl) phenyl sulfide;
2,4,4'-tri (7-mercapto-2,5-dithiaheptyl) phenyl sulfide and the like can be mentioned, and these can be used alone or as a mixture of two or more.
Among them, trimethylolpropane tristhioglycolate, trimethylolpropane tristhiopropionate, pentaerythritol tetrakisthioglycolate, pentaerythritol tetrakisthiopropionate, 4,4′-bis (4-mercapto-2) -Thiabutyl) phenyl sulfide and 4,4'-bis (7
—Mercapto-2,5-dithiaheptyl) phenyl sulfide can be suitably used in the present invention from the viewpoint that it provides an optical material having a high refractive index and a high Abbe number and is excellent in economical efficiency.

Representative examples of the aliphatic sulfide include, for example, bis (2-mercaptoethyl) sulfide, bis (3-mercaptopropyl) sulfide, bis (4-mercaptobutyl) sulfide, bis (8-mercaptooctyl) sulfide and the like. These can be used alone or in combination of two or more. Among these, bis (2-mercaptoethyl) sulfide is
From the viewpoint of providing an optical material having a high refractive index and a high Abbe number and being excellent in economical efficiency, it can be suitably used in the present invention.

Typical examples of the aromatic dithiol include, for example, 1,2-benzenedithiol, 1,4-benzenedithiol, 4-methyl-1,2-benzenedithiol,
4-butyl-1,1-benzenedithiol, 4-chloro-1,2-benzenedithiol and the like can be mentioned, and these can be used alone or in combination of two or more.
Among these, 1,4-benzenedithiol can be suitably used in the present invention from the viewpoint of providing an optical material having a high refractive index.

The content of the polythiol represented by the general formula (I) in the curable composition of the present invention is 5% by weight or more, preferably 10% by weight, from the viewpoint of increasing the refractive index of the resin obtained by curing. %, More preferably 20% by weight or more, and from the viewpoint of imparting sufficient curability to the curable composition, 90% by weight or less, preferably 85% by weight.
% By weight, more preferably 80% by weight or less.

The content of the compound capable of being copolymerized with the polythiol in the curable composition of the present invention is preferably 10% from the viewpoint of imparting sufficient curability to the curable composition.
% By weight, preferably 15% by weight or more, more preferably 20% by weight or more, and from the viewpoint of increasing the refractive index of the resin obtained by curing, 95% by weight or less, preferably 90% by weight or less, more preferably Is 80% by weight or less.

When the compound copolymerizable with the polythiol is a polyisocyanate compound, a polyisothiocyanate compound or an isothiocyanate compound having an isocyanate group, the isocyanate group and the isothiocyanate compound of the compound are used. Ratio of the total equivalent number of the nato group to the total equivalent number of the thiol group of the polythiol represented by the general formula (I) and the monomer having a plurality of thiol groups other than the polythiol (the total equivalent of the NCO group and the NCS group) The value of // (total equivalent weight of SH groups) is from 0.5 to 3.
0, preferably 0.5 to 2.0.

Typical examples of the curable composition of the present invention include:
For example, a curable composition comprising the polythiol and a polyisocyanate compound; a curable composition comprising the polythiol and a polyisothiocyanate compound; a polythiol, a polyisocyanate compound, and a plurality of thiol groups other than the polythiol. Curable composition comprising a monomer having a polythiol, a polyisocyanate compound and a monomer having a polymerizable unsaturated bond; curable composition comprising the polythiol and a monomer having a polymerizable unsaturated bond A curable composition comprising the polythiol, a monomer having a polymerizable unsaturated bond, and a monomer having a plurality of thiol groups other than the polythiol; a curable composition comprising the polythiol, an epoxy compound; the polythiol, an epoxy compound; A curable composition comprising a monomer having a polymerizable unsaturated bond; a curable composition comprising the polythiol and an epithio compound; a curable composition comprising the polythiol, an epithio compound and a monomer having a polymerizable unsaturated bond. be able to.

The curable composition of the present invention contains the polythiol represented by the general formula (I) and a compound copolymerizable with the polythiol as described above, but the object of the present invention is not hindered. Within the range, other copolymerizable compounds may be contained.

The curable composition of the present invention can be cured by a usual method, for example, by heating, irradiation of light such as ultraviolet rays, etc., if necessary, using a polymerization initiator or the like.

When the compound copolymerizable with the polythiol is the polyisocyanate compound, the polyisothiocyanate compound or the isothiocyanate compound having an isocyanate group, the curable composition of the present invention contains: Known curing catalysts can be used. Examples of the curing catalyst include, but are not particularly limited to, dibutyltin dilaurate, dimethyltin dichloride, stannas octoate, and stannic chloride.

When the compound copolymerizable with the polythiol is a monomer having a polymerizable unsaturated bond, a radical polymerization initiator can be used as a polymerization initiator. The radical polymerization initiator is not particularly limited, and examples of such a radical polymerization initiator include, for example,
2,2′-azobis (2-methylbutyronitrile),
2,2'-azobisisobutyronitrile, 2,2'-azobisisovaleronitrile, 2,2'-azobis (2,
Azo compounds such as 4-dimethylvaleronitrile) and 1,1'-azobis (cyclohexane-1-carbonitrile); ketone peroxides such as methyl ethyl ketone peroxide and methyl isobutyl ketone peroxide; benzoyl peroxide; And diacyl peroxides such as 4,4-dichlorobenzoyl peroxide.

When the compound copolymerizable with the polythiol is the epoxy compound, a known curing accelerator can be used. Examples of the curing accelerator include tertiary amines such as triethylamine and hexamethylenetetramine, imidazoles such as 2-ethyl-4-methylimidazole and 2,4-dimethylimidazole, dioctyltin laurate, and tin octylate. Metal salts and the like can be mentioned.

In the present invention, if necessary, the curable composition may contain, for example, a light stabilizer, an ultraviolet absorber, an antioxidant, a coloring inhibitor, a polymerization inhibitor, a release agent, and a defoaming agent. Additives such as a bluing agent and a fluorescent dye may be appropriately compounded as necessary.

The curable composition of the present invention thus obtained has excellent properties such as a high refractive index, a high Abbe number and a small specific gravity, and is excellent in handleability.

Accordingly, the curable composition of the present invention comprises a plastic lens for spectacles, a Fresnel lens, a lenticule lens, an optical disk substrate, a plastic optical fiber,
It can be suitably used as a raw material for optical materials such as prism sheets for LCDs, light guide plates, diffusion sheets, etc., paints, adhesives, sealants and the like. In particular, the curable composition of the present invention can be suitably used for an optical material.

The optical material of the present invention is obtained by curing the curable composition.

For the curing reaction of the curable composition, a copolymerization reaction is carried out according to a generally known method such as heating or irradiation with a light beam such as ultraviolet rays, using the curing catalyst and the polymerization initiator as appropriate. Just do it.

For example, the polymerization temperature and the polymerization time during the copolymerization cannot be unconditionally specified because they vary depending on the composition of the curable composition, the application, the type of the polymerization initiator used, and the amount of the polymerization initiator used. Temperature is 0
To 200 ° C, preferably 20 to 150 ° C, and the polymerization time is 0.2 to 100 hours, preferably 1 to 72 hours.

The optical material of the present invention thus obtained has excellent properties such as a high refractive index, a high Abbe number and a small specific gravity.

Therefore, the optical material of the present invention can be used as a plastic lens for spectacles, a Fresnel lens, a lenticule lens, an optical disk substrate, a plastic optical fiber, an LC
It can be suitably used as a raw material for optical materials such as a prism sheet for D, a light guide plate, and a diffusion sheet, a paint, an adhesive, and a sealant.

[0086]

Next, the present invention will be described in more detail with reference to Production Examples and Examples, but the present invention is not limited only to the Examples and the like.

Production Example 1 Cyanuric chloride 18 was placed in a 5-liter four-necked flask.
4.4 g, bis (2-mercaptoethyl) sulfide 3
240.3 g and 1.9 g of tetra-n-butylammonium bromide were charged, and 600 g of a 20% aqueous sodium hydroxide solution was added dropwise over 2 hours while maintaining the temperature at 0 to 10 ° C.

After completion of the dropwise addition, the mixture was stirred at room temperature for 2 hours, neutralized with 304.2 g of 36% by weight hydrochloric acid, and then separated into an organic layer and an aqueous layer. The obtained organic layer was washed with water and concentrated to obtain 2,4,4 in which n is 2 in general formula (I).
6-tri (5-mercapto-3-thiapentathio)-
511.1 g of 1,3,5-triazine was obtained.

The obtained 2,4,6-tri (5-mercapto-3-thiapentathio) -1,3,5-triazine is shown in Table 1 as polythiol A.

Production Example 2 Cyanuric chloride 18 was placed in a 5-liter four-necked flask.
4.6 g, 1978.2 g of 1,2-ethanedithiol and 1.9 g of tetra-n-butylammonium bromide were charged, and in the same manner as in Production Example 1, n was 1 in general formula (I). 340 g of 4,4,6-tri (2-mercaptoethylthio) -1,3,5-triazine were obtained.

The obtained 2,4,6-tri (2-mercaptoethylthio) -1,3,5-triazine is shown in Table 1 as polythiol B.

Production Example 3 Cyanuric chloride 18 was placed in a 5-liter four-necked flask.
4.6 g, 1318.8 g of 1,2-ethanedithiol,
Bis (2-mercaptoethyl) sulfide 1080.1
g, 1.9 g of tetra-n-butylammonium bromide, and polythiol mixture 3 was prepared in the same manner as in Production Example 1.
95 g were obtained.

The resulting polythiol mixture was separated and purified by column chromatography, and the compound of formula (I)
(2-mercaptoethylthio)-(5
296 g of -mercapto-3-thiapentathio) -1,3,5-triazine was obtained.

The obtained di (2-mercaptoethylthio)
-(5-Mercapto-3-thiapentathio) -1,3,3
5-Triazine is shown as polythiol C in Table 1.

Production Example 4 Cyanuric chloride 18 was placed in a 5-liter four-necked flask.
4.6 g, 659.4 g of 1,2-ethanedithiol, bis (2-mercaptoethyl) sulfide 2160.2
g, 1.9 g of tetra-n-butylammonium bromide, and the polythiol mixture 45 was prepared in the same manner as in Production Example 1.
0 g was obtained.

The obtained polythiol mixture was separated and purified by column chromatography, and the compound of formula (I)
Is 1 and 2, (2-mercaptoethylthio) -di (5
-Mercapto-3-thiapentathio) -1,3,5-triazine 330 g was obtained. The obtained (2-mercaptoethylthio) -di (5-mercapto-3-thiapentathio) -1,3,5-triazine is shown as polythiol D in Table 1.

Production Example 5 Cyanuric chloride 18 was placed in a 5-liter four-necked flask.
4.6 g, 1,2-ethanedithiol 659.4 g, bis (2-mercaptoethyl) sulfide 1080.1 g
Then, 1501.1 g of 8-mercapto-3,6-dithiaoctanethiol and 1.9 g of tetra-n-butylammonium bromide were charged, and 505 g of a polythiol mixture was obtained in the same manner as in Production Example 1.

The obtained polythiol mixture was separated and purified by column chromatography, and the compound of formula (I)
Is 1, 2, and 3 (2-mercaptoethylthio)-
328 g of (5-mercapto-3-thiapentathio)-(8-mercapto-3,6-dithiaoctathio) -1,3,5-triazine was obtained.

The obtained (2-mercaptoethylthio)-
(5-Mercapto-3-thiapentathio)-(8-mercapto-3,6-dithiaoctathio) -1,3,5-triazine is shown in Table 1 as polythiol E.

[0100]

[Table 1]

Example 1 10 g of the polythiol A obtained in Production Example 1 and 10 g of divinylbenzene (purity: 96%) were uniformly mixed to obtain a curable composition.

Next, based on 100 parts by weight of the curable composition, 2,2'-azobis (2
-Methylbutyronitrile) after adding 0.8 parts by weight,
The curable composition was sufficiently degassed, poured into a glass mold having a diameter of 5 cm and a thickness of 0.3 cm, and kept at 55 ° C. for 6 hours.

Next, the temperature was raised to 100 ° C. over 5 hours,
After maintaining at 100 ° C. for 3 hours, the mold was removed, and an optical material in which the curable composition was cured was obtained. The obtained optical material was uniform and colorless and transparent.

Next, the physical properties of the obtained optical material were examined according to the following methods. Table 2 shows the results.

(1) Refractive index and Abbe number The refractive index and Abbe number at 20 ° C. are measured using an Abbe refractometer (manufactured by Atago, 4T type).

(2) Specific gravity Measured according to JIS-K6911.

Examples 2 to 11 In Example 1, polythiols A to E shown in Table 1 were used as polythiols, and a high-purity divinylbenzene having a purity of 96% was used as a compound copolymerizable with the polythiols A to E (Table 2). , DVB), ethylene glycol dimethacrylate (abbreviated as EGDM in Table 2), bis (4-methacryloylthiophenyl) sulfide (MP in Table 2)
SMA), styrene (abbreviated as St in Table 2), bis (2-mercaptoethyl) sulfide (DM in Table 2)
DS) or pentaerythritol tetrakisthiopropionate (abbreviated as PETP in Table 2),
Example 1 was repeated except that the composition was adjusted as shown in Table 2.
In the same manner as in the above, a curable composition of each composition was obtained.

Using the obtained curable composition, an optical material was prepared in the same manner as in Example 1, and each physical property was examined. Table 2 shows the results.

[0109]

[Table 2]

From the results shown in Table 2, Examples 1 to 11
It can be seen that all of the optical materials obtained in (1) have a high refractive index, a high Abbe number, and a low specific gravity.

That is, it can be seen that all of the obtained optical materials have excellent characteristics desired for the optical materials.

Example 12 15 g of the polythiol A obtained in Production Example 1 and 5.4 g of m-xylylene diisocyanate were uniformly mixed to obtain a curable resin composition.

Next, based on 100 parts by weight of the curable composition, 2,2′-azobis (2
-Methylbutyronitrile) was added, and the curable composition was sufficiently degassed. The mixture was poured into a glass mold having a diameter of 5 cm and a thickness of 0.3 cm, and kept at 60 ° C. for 5 hours. . Next, the temperature was raised to 100 ° C. over 10 hours,
After maintaining at 100 ° C. for 3 hours and then at 120 ° C. for 3 hours, the mold was removed and an optical material was obtained by curing the curable composition. The obtained optical material was uniform and colorless and transparent.

Next, the physical properties of the obtained optical material were measured in Example 1.
Investigation was performed in the same manner as described above. Table 3 shows the results.

Examples 13 to 18 In Example 12, polythiols A to E in Table 1 were used as polythiols, and m-xylylene diisocyanate (in Table 3) was used as a compound copolymerizable with the polythiols A to E. mXDI), pentaerythritol tetrakisthiopropionate (abbreviated as PETP in Table 3), or 4,4′-diphenylmethane diisocyanate (abbreviated as MDI in Table 3), and the composition shown in Table 3 is obtained. A curable composition of each composition was obtained in the same manner as in Example 12, except for the above changes.

Example 12 Using the Curable Composition Obtained
Optical materials were prepared in the same manner as described above, and their physical properties were examined. Table 3 shows the results.

[0117]

[Table 3]

From the results shown in Table 3, Examples 12 to 1 were obtained.
Each of the optical materials obtained in 8 has a high refractive index,
It can be seen that the Abbe number is high and the specific gravity is low.

That is, it can be seen that all of the obtained optical materials have excellent characteristics desired for the optical materials.

[0120]

The curable composition of the present invention has excellent curability, and the optical material obtained by using the curable composition is:
It has an excellent property of providing a resin having a high refractive index equal to or higher than that of a conventional optical material, a high Abbe number, and a low specific gravity.

Therefore, the curable composition of the present invention can be suitably used not only as an optical material but also as various raw materials such as paints, adhesives, sealing materials and the like.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI G11B 7/24 526 G11B 7/24 526N // C07D 251/38 C07D 251/38 C (72) Inventor Michio Suzuki Kako-gun, Hyogo 346 Miyanishi, Harima-cho, 1st Research Laboratory, Sumitomo Seika Co., Ltd. (72) Inventor Hiroyuki Hata 346-1, Miyanishi, Harimacho, Kako-gun, Hyogo Prefecture, 1st Research Laboratories, Sumitomo Seika Chemicals Co., Ltd.

Claims (3)

[Claims] 1. A compound of the general formula (I): (In the formula, n represents 0 which may be the same or different,
5 to 90% by weight of a polythiol represented by the following formula: and a compound 10 copolymerizable with the polythiol.
A curable composition containing 95% by weight. 2. A compound copolymerizable with a polythiol,
Polyisocyanate compounds, polyisothiocyanate compounds, isothiocyanate compounds having an isocyanate group, monomers having a polymerizable unsaturated bond, epoxy compounds, epithio compounds and a plurality of compounds other than the polythiol represented by the general formula (I) The curable composition according to claim 1, which is at least one member selected from the group consisting of monomers having a thiol group. 3. An optical material obtained by curing the curable composition according to claim 1.