JPH11100435A - Composition for optical material and plastic lens - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a composition for optical materials, capable of providing the optical materials having a high refractive index, a high Abbe's number and high transparency and good in physical characteristics and excellent in moldability and to provide a plastic lens prepared from the composition for optical materials. SOLUTION: This composition for optical materials contains the following components A, B and C. When the number of mol of thiol groups in the component A is X, the number of mol of acid anhydride groups in the component B is Y and the total number of mol of expoxy groups and episulfide groups in the component C is Z, X, Y and Z satisfy Z/(X+Y)=0.5-1.5 and X/Y=0.5-20, where the component A is a component composed of a compound having >=250 molecular weight, >=30 mass % sulfur content in the molecule and >=3 thiol groups in the molecule, the component B is a component composed of an acid anhydride, and the component C is a component composed of a compound having at least 2 epoxy groups and/or episulfide groups in the molecule.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composition for an optical material from which an optical material having both a high refractive index and an Abbe number and having good physical properties can be obtained, and a method for polymerizing the composition for an optical material. It relates to the plastic lens obtained.

[0002]

2. Description of the Related Art Synthetic resins are widely used as various optical materials in recent years because they are lightweight and easy to handle as compared with inorganic glass and the like. Among various physical properties required for an optical material, high refractive index, high Abbe number, that is, low dispersion and good physical properties are extremely important. According to the high refractive index optical material, for example, it is possible to make a lens system occupying an important position in an optical device such as a microscope, a camera, a telescope or an eyeglass lens compact, to reduce the weight and to use a spherical surface. Aberrations can be kept small. On the other hand, the fact that the optical material has a high Abbe number, that is, low dispersion, is extremely important in that the chromatic aberration of the lens is reduced. In terms of physical properties, a small specific gravity is important in reducing the weight of the optical material, and having high rigidity is important in reducing the thickness and size of the optical material. Having heat resistance and impact resistance is extremely important in practical use. Further, from the viewpoint of the productivity of the optical material, it is required to have excellent moldability.

[0003] However, even in synthetic resin optical materials,
Similar to inorganic glass optical materials, high refractive index materials tend to have low Abbe number, ie, high dispersion, while high Abbe number materials tend to have low refractive index. For example, "CR-39" is used as an optical material made of a synthetic resin.
And diethylene glycol diallyl carbonate resins. Although this resin has a high Abbe number of 60, it has a very low refractive index of 1.50, so when used as a lens, the edge thickness and the center thickness are large, so that the appearance of the lens is high. There is a problem that the lens becomes worse and the weight of the lens increases. Polymethyl methacrylate resin used in some fields as a lens material also has a high Abbe number of 60 but a low refractive index of 1.49.

On the other hand, as other synthetic resins used as optical materials, polystyrene resins and polycarbonate resins are known, but these synthetic resins have large birefringence and also have high heat resistance and impact resistance. Physical properties were inadequate and not always satisfactory.

In order to solve such problems, development of optical materials made of synthetic resin containing a sulfur atom having a high atomic refractive index has been promoted mainly for the purpose of improving the refractive index.

[0006] For example, Japanese Patent Publication No. 4-58489 and Japanese Patent Application Laid-Open No. 2-270589 disclose a synthetic resin optical material obtained by polymerizing a polythiol compound and a compound having an isocyanate group and / or an isothiocyanate group. Are disclosed. However, in this means, an optical material made of a synthetic resin having a high refractive index can be obtained. However, since the polymerization temperature is relatively low and the polymerization rate is high, heat control during polymerization becomes difficult, and as a result, the obtained synthetic Resin has a problem that coloring and large optical distortion occur. In addition, when a synthetic resin having a sufficiently high refractive index is obtained, there are problems that the Abbe number becomes small and the degree of coloring becomes large.

[0007] Japanese Patent Application Laid-Open No. 1-215816 discloses that a curable composition comprising an epoxy resin, a polyisocyanate compound and a polythiol compound is used, and a urethane reaction and an epoxy reaction are carried out in parallel to form a colored composition. Means for obtaining small sulfur atom-containing urethanized epoxy lenses have been proposed. JP-A-4-329514 discloses a method of curing a composition containing a monomer composed of an epoxide, a curing agent composed of an aromatic acid anhydride or the like, and a refractive index improver composed of a thiol or the like. Thus, means for obtaining a lens material having a high refractive index has been proposed. However, in these means, the curing time of the curable composition in the cast polymerization is about 20 hours, and it takes a considerably long time to mold the optical material, so that high productivity cannot be obtained. There is a problem.

Japanese Patent Application No. 1-504942 (International Publication No. WO / 89/10575) and Japanese Patent Application Laid-Open No. 3-81.
No. 320 discloses a method for obtaining a polysulfide resin lens by subjecting a composition comprising an epoxy group and / or episulfide group, a compound such as polythiol, and an internal release agent to casting polymerization. Proposed. However, the lens obtained by this means has a high refractive index of 1.66 and an Abbe number of 33, but is not sufficient in terms of transparency due to the inclusion of an internal release agent. In addition, since the reaction of the monomer is fast and the pot life of the composition is short, good moldability cannot be obtained.

Japanese Patent Application Laid-Open No. 9-110983 proposes a lens made of a polysulfide resin obtained by reacting a polythiol compound having a specific structure and having four or more functional groups with an epoxy compound. However, this polysulfide resin lens is not sufficiently high in rigidity and heat resistance.

JP-A-8-183816 discloses that a polymerizable composition containing an epoxy oligomer such as bis [4- (2,3-epoxypropylthio) phenyl] sulfide is polymerized to produce a synthetic resin. Means for obtaining optical materials have been proposed. However, in this means, a synthetic resin having an extremely high refractive index of 1.72 can be obtained, but the Abbe number is not sufficiently high.

[0011]

As described above, in the prior art, both the refractive index and the Abbe number are high, the optical properties are high, the transparency is high, and the physical properties are good. There is no known synthetic resin optical material having excellent moldability. The present invention has been made based on the above circumstances, and the object is to have excellent optical properties such as high refractive index and Abbe number, high transparency, and good physical properties. An object of the present invention is to provide a composition for an optical material having an optical material having the following formula (1) and having excellent moldability in cast polymerization.
Another object of the present invention is to provide a plastic lens that has excellent optical properties such as high refractive index and Abbe number, high transparency, and good physical properties.

[0012]

The composition for an optical material of the present invention comprises at least the following components A, B and C, and the number of moles of the thiol group in the component A is X, B Assuming that the number of moles of the acid anhydride group in the component is Y and the total number of moles of the epoxy group and the episulfide group in the component C is Z, condition a Z / (X + Y) = 0.5-1.5, and condition b X /Y=0.5 to 20.

A component: a component having a molecular weight of 250 or more, a sulfur content in the molecule of 30% by mass or more, and a compound having three or more thiol groups in the molecule, B component: acid anhydride Component consisting of a compound having at least two epoxy groups and / or episulfide groups in the molecule.

In the composition for an optical material of the present invention, tetrakis- (7-
It is preferable that mercapto-2,5-dithiaheptyl) methane is contained. Further, as part or all of the component B, selected from phthalic anhydride, hexahydrophthalic anhydride, methyl-5-norbornene-2,3-dicarboxylic anhydride and methylcyclohexene-1,2-dicarboxylic anhydride. Preferably, at least one compound is contained.

The plastic lens of the present invention is characterized by comprising a polymer obtained by subjecting the above-mentioned composition for an optical material to a polymerization treatment.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The composition for an optical material of the present invention includes an A component described below,
It contains B component and C component.

[Component A] The component A is a compound having a molecular weight of 250 or more, a sulfur content in the molecule of 30% by mass or more, and having three or more thiol groups in the molecule (hereinafter referred to as “specified”). A polythiol compound ”)). If not satisfying all of the requirements regarding these molecular weight, sulfur content and the number of thiol groups, the resulting polymer tends to have low refractive index, Abbe number, transparency, and low mechanical properties. is there.

Such a specific polythiol compound is
The molecular weight, sulfur content and number of thiol groups are not particularly limited as long as they satisfy all of the requirements, but the molecular weight is 300 or more, and the sulfur content in the molecule is 35% by mass or more. Is preferred. In particular, tetrakis- (7) represented by the following formula (i) may be used as a part or all of component A in that a polymer having higher refractive index, Abbe number, and transparency and having more excellent mechanical properties can be obtained. −
It is preferable to use mercapto-2,5-dithiaheptyl) methane at a ratio of 50% by mass or more of the component A.

[0019]

Embedded image

The tetrakis- (7) represented by the above formula (i)
-Mercapto-2,5-dithiaheptyl) methane has a molecular weight of 680 and a sulfur content of 56.5% by weight,
It has four thiol groups. The tetrakis- (7-mercapto-2,5-dithiaheptyl) methane can be obtained, for example, by converting bis- (2-mercaptoethyl) sulfite and pentapentaerythrityltetrahalide such as pentaerythrityltetrabromide into sodium hydroxide It is obtained by reacting in the presence of a base such as The reaction of bis- (2-mercaptoethyl) sulfite with pentapentaerythrityl tetrahalide is
It is carried out by mixing the two and stirring while adding the above base under heating. If necessary, a quaternary ammonium salt such as tetra-n-butylammonium bromide or a quaternary phosphonium salt can be used as the reaction catalyst. In the above, the reaction temperature is 30 to
Preferably, the temperature is set to 120 ° C. The usage ratio of bis- (2-mercaptoethyl) sulfite and pentapentaerythrityl tetrahalide is such that bis- (2-mercaptoethyl) sulfite is at least 4 moles, especially 4 moles per mole of pentapentaerythrityl tetrahalide. ~
Preferably it is 50 mol. Further, the use ratio of the base is preferably 4 to 6 mol per 1 mol of pentapentaerythrityl tetrahalide. Further, the usage ratio of the catalyst is preferably 0.01 to 1 mol per 1 mol of pentapentaerythrityl tetrahalide.

Tetrakis- (7-mercapto-2,5-
Specific examples of the specific polythiol compound other than dithiaheptyl) methane include 1,2-bis [(2-mercaptoethyl) thio] -3-mercaptopropane and 2,3-bis [(2-mercaptoethyl) thio] -3-mercaptopropane.
(6-mercapto-1,4-dithiahexyl) -1-propanethiol, 4,8-bis (mercaptomethyl)-
3,6,9-Trithia-1,11-undencanthiol and the like. These specific polythiol compounds can be used alone or in combination of two or more as the component A.

[Component B] The component B is composed of an acid anhydride. As the acid anhydride, an intramolecular cyclic anhydride of a polyvalent carboxylic acid is used. Such acid anhydrides are not particularly limited, but in terms of availability, solubility, etc., phthalic anhydride, hexahydrophthalic anhydride,
Preferred examples thereof include methyl-5-norbornene-2,3-dicarboxylic anhydride and methylcyclohexene-1,2-dicarboxylic anhydride. These acid anhydrides are preferably used at a ratio of 30% by mass or more of the component B. Specific examples of acid anhydrides other than the above compounds include tetrahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, dodecinyl succinic anhydride and the like. These acid anhydrides can be used alone or in combination of two or more as the component B.

[Component C] The component C is a compound having at least two epoxy groups and / or episulfide groups in the molecule. Specific examples include a compound having two or more epoxy groups, a compound having two or more episulfide groups, and a compound having at least one epoxy group and one or more episulfide group.

Specific examples of the compound having two or more epoxy groups include bisphenol A diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, brominated bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, and hydrogenated bisphenol F
Diglycidyl ether, resorcin diglycidyl ether, hydroquinone diglycidyl ether, bisphenol S diglycidyl ether, 9,9′-bis (4-hydroxyphenyl) fluoro orange glycidyl ether,
Glycidyl ethers such as tris (hydroxyphenyl) methane tridiglycidyl ether and trimethylolpropane tridiglycidyl ether; bis [4- (2,
3-epoxypropylthio) phenyl] sulfide,
1,4-di (2,3-epoxypropylthiophenyl)
Glycidyl thioethers such as benzene; diglycidyl phthalate, diglycidyl hexahydrophthalate,
Glycidyl esters such as diglycidyltetrahydrophthalate and dimethyldiglycidylhexahydrophthalate; N, N ′, N, N′-tetraglycidyldiaminodiphenylmethane, N, N ′, N, N′-tetraglycidylxylylenediamine, Glycidylamines such as N-diglycidylcyclohexylamine triglycidyl isocyanurate; 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 3,4-epoxycyclohexylethyl-3,4
-Epoxycyclohexanecarboxylate, vinylcyclohexene dioxide, allylcyclohexene dioxide, 2- (3,4-epoxycyclohexyl-5,5
-Spiro-3,4-epoxy) cyclohexane-metadioxane, bis (3,4-epoxycyclohexyl) adipate, bis (3,4-epoxycyclohexylmethyl) adipate, bis (3,4-epoxycyclohexyl) ether, bis (3 Alicyclic epoxies such as 3,4-epoxycyclohexylmethyl) ether and bis (3,4-epoxycyclohexyl) diethylsiloxane can be mentioned.

Examples of the compound having two or more episulfide groups include compounds in which all the epoxy groups in the above compounds exemplified as having two or more epoxy groups are substituted with episulfide groups. Also,
Examples of the compound having one or more epoxy groups and one or more episulfide groups include compounds in which some of the epoxy groups in the above compounds exemplified as having two or more epoxy groups are substituted with an episulfide group.

These compounds can be used alone or in combination of two or more as the component C. However, in view of easy handling, compounds which are liquid at room temperature are preferable. In particular, bisphenol A diglycidyl ether, Preferred are bisphenol F diglycidyl ether, resorcin didiglycidyl ether, and bis [4- (2,3-epoxypropylthio) phenyl] sulfide. Also,
In terms of obtaining a high refractive index, bis [4- (2,3-epoxypropylthio) phenyl] sulfide, bis [4
-(2,3-Epithiopropylthio) phenyl] sulfide is preferred.

The above bis [4- (2,3-epoxypropylthio) phenyl] sulfide is, for example, bis (4-
A method in which an epihalohydrin is added to an (mercaptophenyl) sulfide and then a ring-closing reaction is performed (J. App.
l. Poly. Sci,. 39 volumes, 1623 (1990
), U.S. Pat. No. 2,731,437).

The above bis [4- (2,3-epithiopropylthio) phenyl] sulfide is disclosed in JP-A-9-3058.
No. 4,019,045, namely the above-mentioned bis [4-
(2,3-epoxypropylthio) phenyl] sulfide can be produced by thioglycidylation by reacting with thiourea or thiocyanate in an organic solvent.

In the above, as the thiocyanate,
Potassium thiocyanate, ammonium thiocyanate, or the like can be used. The thiourea or thiocyanate is used in an amount of 4 equivalents or less, preferably 3 equivalents or less, based on bis [4- (2,3-epoxypropylthio) phenyl] sulfide as a raw material. Examples of the organic solvent include halogenated hydrocarbons such as methylene chloride, 1,2-dichloroethane, chlorobenzene, and o-dichlorobenzene, hydrocarbons such as n-hexane, n-heptane, cyclohexane, toluene, and xylene; tetrahydrofuran; Ethers such as 1,4-dioxane, methanol,
Alcohols such as ethanol and i-propanol can be used. The reaction temperature is 0 to 80 ° C, preferably 10 to 60 ° C. After completion of the reaction, water was added to the obtained product solution, then the organic solvent layer and the aqueous layer were separated, and the organic solvent layer was washed with water. -(2,3-Epithiopropylthio) phenyl] sulfide is obtained.

In the composition for optical materials of the present invention, the above components A, B and C are required to be contained as essential components, and further, the following conditions must be satisfied. That is, when the number of moles of the thiol group in the component A is X, the number of moles of the acid anhydride group in the component B is Y, and the total number of moles of the epoxy group and the episulfide group in the component C is Z, the condition a Z / (X + Y ) = 0.5-1.5, preferably Z / (X + Y) = 0.8-1.2, and condition b X / Y = 0.5-20, preferably X / Y = 1
It is necessary that the component A, the component B, and the component C are contained in proportions satisfying the following conditions. In the present invention, the “acid anhydride group” refers to a group represented by the following formula (2).

[0031]

Embedded image

If the conditions a and b are not satisfied, the following problems occur. (1) Regarding the condition a: When the value of Z / (X + Y) is less than 0.5, that is, when the ratio of the C component to the total of the A component and the B component is too small, the obtained polymer is The refractive index or Abbe number may be low, or the pot life of the composition may be too short to obtain good moldability. On the other hand, when the value of Z / (X + Y) exceeds 1.5, that is, C with respect to the sum of the A component and the B component
If the proportion of the components is too large, the heat resistance of the obtained polymer is low, and the pot life of the composition is short, so that good moldability cannot be obtained. (2) Regarding the condition b: When the value of X / Y is less than 0.5, that is, when the ratio of the component A to the component B is too small, the obtained polymer has a low refractive index. Become. On the other hand, when the value of X / Y exceeds 20, ie, B
When the ratio of the component A to the component is excessive, bubbles are generated in the obtained polymer, and good moldability cannot be obtained.

In the composition for an optical material of the present invention, if necessary, a monomer component other than the A component, the B component and the C component (hereinafter referred to as “other component”), together with the above component A, B component and C component. Of a monomer component ”). As such other monomer components, acryloyl group, methacryloyl group, vinyl group, hydroxyl group,
A compound having an amino group, an amide group, a carboxy group, or the like can be used. The use ratio of the other monomer component is preferably 50 parts by mass or less, more preferably 30 parts by mass or less, based on 100 parts by mass of the total of the component A, the component B and the component C. When this proportion exceeds 50 parts by mass, it becomes difficult to obtain a polymer having a high refractive index.

The composition for an optical material of the present invention may contain an antistatic agent, a coloring agent, an ultraviolet absorber, a heat stabilizer, an antioxidant, a filler, a release agent and the like, if necessary. it can. Further, in order to accelerate the curing reaction, if necessary, tertiary amines such as triethylamine, hexamethylenetetramine and tetramethylguanidine; imidazoles such as 2-ethyl-4-methylimidazole and 2,4-diethylimidazole Dioctyltin dilaurate;
Metal salts such as tin octylate can be contained. Furthermore, if necessary, a cationic polymerization initiator, a radical polymerization initiator, and a photopolymerization initiator can be contained.

The plastic lens of the present invention is prepared by subjecting the composition for optical material described above to a usual polymerization method, for example, a thermal polymerization method.
It is obtained by performing a polymerization treatment by a photopolymerization method or the like.
As the polymerization system for carrying out the addition polymerization reaction of the component A and the component B with the component C, it is preferable to use a cast polymerization method which can directly obtain a shape as a target optical material.

The casting polymerization method is a well-known technique and can be applied to the present invention as it is. Containers for casting polymerization include plate, lens, cylinder, prism, cone, sphere,
Other molds or molds or other containers designed according to the purpose or application are used. As its material,
Inorganic glass, plastic, metal, or any other material depending on the purpose can be selected. Further, the casting polymerization container may be subjected to a hydrophobic treatment such as a water-repellent coating in order to improve the releasability. The actual polymerization reaction is
Injection of the composition for optical material into a casting polymerization container, for example, by heating, but the prepolymer having a higher viscosity is obtained by reacting the composition for optical material to a certain extent in advance using another reaction vessel. Alternatively, the syrup may be poured into a casting polymerization vessel to complete the polymerization. Further, a method of shaving a plate-shaped or lump-shaped polymer obtained by a cast polymerization method into a desired shape can also be used. The plastic lens thus obtained may be subjected to a post-polishing treatment, an antistatic treatment or a post-treatment such as applying a suitable inorganic material or an organic coating agent to the surface to increase the surface hardness, if necessary. It can also be applied.

[0037]

Hereinafter, the present invention will be described with reference to examples.
The present invention is not limited by these. still,
In the following examples, “parts” means “parts by mass”. In the following examples, the compounds used as the component A, the component B, and the component C are as follows.

[Component A] Specific polyol compound (1): A 1000 ml four-necked flask equipped with a stirrer, a thermometer, and a cooler was prepared, and bis- (2-
Mercaptoethyl) sulfite 600 g (3.9 mol), pentaerythrityl tetrabromide 50 g (0.
129 mol) and 4.1 g (0.0127 mol) of tetra-n-butylammonium bromide as a catalyst, which were heated to 80 to 100 ° C., and then, under a nitrogen atmosphere, 219 g (0% .5
3 mol) was added dropwise. Thereafter, the reaction system is heated to 80 to 100 ° C.
For 3 hours. Next, after cooling the obtained reaction solution to 50 ° C., the aqueous layer was separated, and the obtained organic layer was washed twice with water and concentrated under reduced pressure. By purifying the obtained concentrate using silica gel column chromatography, tetrakis- (7-) represented by the formula (i) is obtained.
72.6 g (0.107 mol) of mercapto-2,5-dithiaheptyl) methane (molecular weight: 680, sulfur content: 56.5% by mass, number of thiol groups: 4) were obtained. This tetrakis- (7-mercapto-2,5-dithiaheptyl) methane is referred to as “specific polythiol compound (1)”.

Specific polythiol compound (2): 1,2
-Bis [(2-mercaptoethyl) thio] -3-mercaptopropane (molecular weight: 260, sulfur content: 61.5 mass%, number of thiol groups: 3), polythiol compound for comparison (1): pentaerythritol thiopropionate (Molecular weight 489, sulfur content 2
6.2% by mass, number of thiol groups 4), Comparative polythiol compound (2): bis- (2-mercaptoethyl) sulfide (molecular weight: 154, sulfur content: 62.3% by mass, number of thiol groups: 2)

[Component B] Acid anhydride (1): hexahydrophthalic anhydride, acid anhydride (2): methylcyclohexene-1,2-dicarboxylic anhydride, acid anhydride (3): phthalic anhydride , Acid anhydride (4): anhydrous methyl-5-norbornene-2,
3-dicarboxylic acid

[Component C] Epoxy compound (1): Bis (4-mercaptophenyl) sulfide 1 was placed in a 1-liter four-necked flask.
00 g, 150 g of epichlorohydrin and 300 g of dioxane, 20 g of a 10% by mass aqueous solution of potassium hydroxide was added dropwise at 10 ° C.
Allowed to react for hours. Thereafter, the temperature was raised to 60 ° C., and 45 mass%
90 g of an aqueous sodium hydroxide solution is added dropwise at 60 ° C.
Allowed to react for hours. Then, water and toluene were added to the obtained reaction solution, and an aqueous layer and an organic layer were separated. After the obtained organic layer was neutralized and washed with water, the solvent was distilled off to obtain 140 g of bis [4- (2,3-epoxypropylthio) phenyl] sulfide. The obtained screw [4
- (2,3-epoxypropyl) phenyl] sulfide is a colorless transparent liquid, its refractive index N _D 1.
669. This bis [4- (2,3-epoxypropylthio) phenyl] sulfide is referred to as an epoxy compound (1).

Epoxy compound (2): bisphenol F
Diglycidyl ether (epoxy equivalent: 160), epoxy compound (3): resorcin didiglycidyl ether (epoxy equivalent: 118)

Episulfide compound (1): In a 1 l four-necked flask equipped with a stirrer, a thermometer and a Dimroth condenser, 72.6 g of the epoxy compound (1) was added.
(0.2 mol), 200 g of methylene chloride and 160 g of methanol were charged and heated to 40 ° C. Then, while maintaining the temperature at 40 to 45 ° C, 61 g of thiourea (0.8 g
Mol) was added and the mixture was stirred at the same temperature for 4 hours. Thereafter, the mixture was cooled to room temperature, 200 g of water was added, and the mixture was stirred for 30 minutes. Then, the organic layer and the aqueous layer were separated, and the obtained organic layer was washed twice with 200 g of water. Further, the solvent was distilled off, followed by recrystallization with a mixed solvent of toluene / n-hexane. White crystals were obtained. An analysis was performed to determine the structure of this white crystal. The results are shown below.

Melting point: 41.5-43.0 ° C., Refractive index: N _D = 1.703, Elemental analysis: Carbon; 54.80% by mass (theoretical 54.7)
4.55% by mass (theoretical value: 4.60% by mass); sulfur: 40.65% by mass (theoretical value: 40.62% by mass); infrared absorption spectrum (KBrcm ^-1 ): 2923 , 14
73, 1388, 1099, 1008, 806, ¹ H-nuclear magnetic resonance spectrum (CDCl ₃ solvent, based on tetramethylsilane) δ (ppm): 7.5 to 7.2
(M, 8H, aromatic ring hydrogen), 3.6 to 2.1 (m, 10
H, epithiopropylthio hydrogen)

From the results of the above analysis, the white crystal was bis [4
-(2,3-epithiopropylthio] phenyl) sulfide. The yield was 73.8 g, and the yield was 93.5% based on the starting material bis (4- (2,3-epoxypropylthio) phenyl) sulfide. The obtained bis [4- (2,3-epithiopropylthio) phenyl] sulfide is referred to as an episulfide compound (1).

<Example 1> After uniformly heating and mixing 38 parts of the specific polythiol compound (1) and 14 parts of the acid anhydride (1) as the component A, and 48 parts of the acid anhydride (2) as the component C, Was subjected to a degassing treatment to prepare a composition for an optical material. A part of the composition for an optical material was injected into a glass lens mold having been subjected to a hydrophobic treatment,
And heated to 90 ° C over 4 hours,
Then, the temperature was raised to 130 ° C. over 2 hours,
Heated for hours. Thus, the polymerization was completed by sequentially heating at different temperatures for a total of 14 hours, thereby producing a -2 diopter lens.

<Examples 2 to 8 and Comparative Examples 1 to 6>
A composition for an optical material was prepared according to the prescription shown in Table 1, and a lens was produced in the same manner as in Example 1 except that this composition for an optical material was used.

[0048]

[Table 1]

In Table 1, the numbers in parentheses in Comparative Examples 1 and 2 indicate Z when the number of moles of the thiol group in the comparative polythiol compound (1) or the comparative polythiol compound (2) is X. / (X + Y)
Or the value of X / Y.

The compositions for optical materials according to Examples 1 to 8 and Comparative Examples 1 to 6 and the lenses obtained from these compositions for optical materials were evaluated for the following performance. [Moldability] The lens was observed to check for the occurrence of bubbles, and a pot life test was performed on the composition for optical materials as follows. Pot life test: After allowing the composition for optical materials to stand at 40 ° C. for 2 hours, the presence or absence of an increase in the viscosity of the composition for optical materials is visually determined. If no bubbles were generated in the lens and no increase in the viscosity of the composition for optical materials was observed in the pot life test, it was evaluated as good. [Rigidity] The lens was deformed by hand, and the lens having a sufficient rigidity was evaluated as ○, and the lens with insufficient rigidity was evaluated as ×. [Visible light transmittance] The visible light transmittance of the lens was measured according to JIS K7105. [Refractive index and Abbe number] Using an Abbe refractometer, 20 ° C
Was measured for the refractive index and Abbe number of the lens. [Specific gravity] The specific gravity of the lens was measured according to ASTM D792. Table 2 shows the results.

[0051]

[Table 2]

As is clear from the results in Table 2, Example 1
According to the compositions for optical materials according to Nos. To 8, the refractive index is 1.6.
0 or more, Abbe number is 25.0 or more and high, and visible light transmittance is 90% or more. It has excellent optical properties especially as a lens, and has excellent physical properties such as high rigidity and low specific gravity. It was confirmed that the material was obtained, and that good moldability was obtained in the casting polymerization. On the other hand, the compositions according to Comparative Examples 1 to 6 had the following problems.

Since the composition according to Comparative Example 1 did not contain the specific polythiol compound essential as the component A, the obtained polymer had a low refractive index. In the composition according to Comparative Example 2, since the specific polythiol compound essential as the component A was not contained, the obtained polymer had a low refractive index and insufficient rigidity. In the composition according to Comparative Example 3, since the value of X / Y was less than 0.5, the obtained polymer had a low refractive index. In the composition according to Comparative Example 4, since the value of X / Y exceeded 20, the polymerization reaction was rapid and foaming occurred during the polymerization. As a result, bubbles were generated in the obtained polymer. And good moldability could not be obtained. The obtained polymer had insufficient rigidity. In the composition according to Comparative Example 5, Z / (X +
Since the value of Y) was less than 0.5, in the pot life test, a remarkable increase in viscosity was recognized in the composition, and good moldability was not obtained. The obtained polymer had insufficient rigidity. In the composition according to Comparative Example 6, since the value of Z / (X + Y) exceeded 1.5, in the pot life test, a remarkable increase in viscosity was observed in the composition, and good moldability was not obtained. Was. The obtained polymer had insufficient rigidity.

[0054]

According to the composition for an optical material of the present invention, an optical material having excellent optical properties such as high refractive index and high Abbe number and high transparency and excellent physical properties can be obtained. can get. In addition, since the composition for optical materials of the present invention has excellent moldability in cast polymerization, high productivity can be obtained. The plastic lens of the present invention has both high refractive index and Abbe number, and excellent optical properties such as high transparency,
It has good physical properties.

Claims (4)

[Claims] 1. A composition comprising at least the following components A, B and C, wherein the number of moles of thiol groups in component A is Y, the number of moles of acid anhydride groups in component B is Y, and When the total number of moles of the epoxy group and the episulfide group is Z, the condition a Z / (X + Y) = 0.5 to 1.5 and the condition b X / Y = 0.5 to 20 are satisfied. Composition for an optical material. A component: a component having a molecular weight of 250 or more, a sulfur content in the molecule of 30% by mass or more, and a compound comprising three or more thiol groups in the molecule B component: a component C comprising an acid anhydride Ingredient: Ingredient consisting of a compound having at least two epoxy groups and / or episulfide groups in the molecule. 2. The composition for an optical material according to claim 1, wherein tetrakis- (7-mercapto-2,5-dithiaheptyl) methane is contained as part or all of the component A. 3. A method according to claim 1, wherein part or all of the component B comprises phthalic anhydride, hexahydrophthalic anhydride, methyl-5 anhydride.
3. The composition according to claim 1, wherein the composition contains at least one compound selected from -norbornene-2,3-dicarboxylic acid and methylcyclohexene-1,2-dicarboxylic anhydride. Compositions for optical materials. 4. A plastic lens comprising a polymer obtained by subjecting the composition for optical material according to claim 1 to a polymerization treatment.