JP5655613B2 - Composition for optical materials - Google Patents

Description

  The present invention relates to a composition for an optical material and the like, and more particularly to an optical material such as a plastic lens, a prism, an optical fiber, an information recording substrate, and a filter, and more particularly a composition for an optical material suitable for a plastic lens.

  In recent years, plastic materials have been widely used in various optical materials, particularly eyeglass lenses, because they are light and tough and easy to dye. The performance required particularly for optical materials, especially spectacle lenses, is low specific gravity, high transparency and low yellowness, high heat resistance, high strength, etc. as physical properties, and high refractive index and high optical performance. Abbe number. A high refractive index makes it possible to reduce the thickness of the lens, and a high Abbe number reduces chromatic aberration of the lens. However, as the refractive index increases, the Abbe number decreases, and studies are being made to improve both simultaneously. Among these studies, the most typical method is a method using an episulfide compound (see Patent Document 1).

  In order to improve oxidation resistance, a composition in which a thiol compound is added to an episulfide compound has been proposed (see Patent Document 2). Further, studies aiming at a high refractive index have been conducted, and a composition comprising sulfur, episulfide and thiol has been proposed (see Patent Documents 3 and 4).

  However, these thiol-containing compositions sometimes turn yellow when polymerized and cured. Since it is an optical material application, if it changes color after curing, it becomes defective and enormous loss occurs. Accordingly, there has been a demand for a method that predicts whether or not yellow discoloration occurs after curing in a stage before curing, and enables determination of quality.

Japanese Patent Laid-Open No. 9-110979 Japanese Patent Laid-Open No. 10-298287 Japanese Patent Laid-Open No. 2001-2783 Japanese Patent Laid-Open No. 2004-137482

  The problem to be solved by the present invention is for an optical material comprising an episulfide compound or a composition containing the same that predicts and discriminates the occurrence or non-occurrence of yellow discoloration after curing at the stage before polymerization curing. It is to provide a composition or the like.

  As a result of intensive studies in view of such circumstances, the present inventors have solved the problem with an episulfide compound having a total content of iron, chromium, and nickel of 5.0 ppm or less, and have reached the present invention.

That is, the present invention is as follows.
<1> An optical material obtained by polymerizing an episulfide compound having a total content of iron, chromium and nickel of 5.0 ppm or less.
<2> A composition for an optical material comprising an episulfide compound having a total content of iron, chromium and nickel of 5.0 ppm or less and a polythiol compound.
<3> The composition for optical materials according to <2>, further containing a polyisocyanate compound.
<4> The composition for optical materials according to <2> or <3>, further containing sulfur.
<5> An optical material obtained by polymerizing the composition for optical materials according to any one of <2> to <4>.
<6> The optical material according to <1> or <5>, wherein an annealing treatment is performed after polymerization.

  From the episulfide compound or a composition containing the same according to the present invention, which is difficult in the prior art, predicts and discriminates the occurrence of yellow discoloration after curing at the stage before polymerization curing, and makes it possible to judge the quality. It became possible to provide the composition for optical materials which becomes.

The episulfide compounds used in the present invention include all episulfide compounds, but as specific examples, they are listed separately as compounds having a chain aliphatic skeleton, an aliphatic cyclic skeleton, and an aromatic skeleton.
Examples of the compound having a chain aliphatic skeleton include compounds represented by the following formula (1).

(However, m represents an integer of 0 to 4, and n represents an integer of 0 to 2.)

  Examples of the compound having an aliphatic cyclic skeleton include compounds represented by the following formula (2) or (3).

(P and q each independently represents an integer of 0 to 4)

(P and q each independently represents an integer of 0 to 4)
Examples of the compound having an aromatic skeleton include compounds represented by the following formula (4).

(P and q each independently represents an integer of 0 to 4)

  Among them, preferred compounds are those represented by the above formula (1) having a chain aliphatic skeleton, specifically, bis (β-epithiopropyl) sulfide, bis (β-epithiopropyl) disulfide, bis (Β-epithiopropyl) trisulfide, bis (β-epithiopropylthio) methane, 1,2-bis (β-epithiopropylthio) ethane, 1,3-bis (β-epithiopropylthio) propane 1,4-bis (β-epithiopropylthio) butane, bis (β-epithiopropylthioethyl) sulfide. Particularly preferred compounds are bis (β-epithiopropyl) sulfide (n = 0 in the above formula (1)), bis (β-epithiopropyl) disulfide (m = 0 in the above formula (1), n = 1). The most preferred compound is bis (β-epithiopropyl) sulfide (n = 0 in the above formula (1)).

  Examples of the episulfide compound having an aliphatic cyclic skeleton include 1,3 and 1,4-bis (β-epithiopropylthio) cyclohexane (p = 0, q = 0 in the above formula (2)), 1,3 And 1,4-bis (β-epithiopropylthiomethyl) cyclohexane (p = 1, q = 1 in the above formula (2), bis [4- (β-epithiopropylthio) cyclohexyl] methane, 2, 2-bis [4- (β-epithiopropylthio) cyclohexyl] propane, bis [4- (β-epithiopropylthio) cyclohexyl] sulfide, 2,5-bis (β-epithiopropylthio) -1, 4-dithiane (p = 0, q = 0 in the above formula (3)), 2,5-bis (β-epithiopropylthioethylthiomethyl) -1,4-dithiane and the like can be mentioned.

  Examples of the episulfide compound having an aromatic skeleton include 1,3 and 1,4-bis (β-epithiopropylthio) benzene (p = 0, q = 0 in the above (4)), 1, 3 and 1 , 4-bis (β-epithiopropylthiomethyl) benzene (p = 1, q = 1 in the above formula (4), bis [4- (β-epithiopropylthio) phenyl] methane, 2,2- Bis [4- (β-epithiopropylthio) phenyl] propane, bis [4- (β-epithiopropylthio) phenyl] sulfide, bis [4- (β-epithiopropylthio) phenyl] sulfine, 4, 4-bis (β-epithiopropylthio) biphenyl and the like can be mentioned.

  The total content of iron, chromium and nickel in the episulfide compound may be any measuring method as long as the total content of iron, chromium and nickel can be measured, but preferably using an ICP emission spectrometer. taking measurement. The measurement is carried out according to a conventional method after pretreatment of the episulfide compound with an acid such as sulfuric acid or nitric acid. By performing these measurements, an episulfide compound having a total content of iron, chromium, and nickel of 5.0 ppm or less is used. Preferably it is 2.0 ppm or less, More preferably, it is 1.0 ppm or less, More preferably, it is 0.5 ppm or less, Most preferably, it is 0.3 ppm or less.

  When the total content of iron, chromium, and nickel exceeds 5.0 ppm, these episulfide compounds or compositions containing the same turn yellow and become unusable when polymerized and cured. Therefore, by measuring the total content of iron, chromium, and nickel, it is possible to predict and discriminate the occurrence of discoloration to yellow without polymerization and hardening, and to judge the quality of the episulfide compound.

When the total content of iron, chromium, and nickel exceeds 5.0 ppm, it is an effective technique to set the content to 5.0 ppm or less through a purification process. It is also an effective technique to obtain a more preferable, more preferable, and most preferable state by further purification. Examples of the purification method include water washing, distillation, column separation operation, adsorbent treatment, ion exchange resin treatment, and the like, but water washing and distillation are preferred.

  Washing with water may or may not use a solvent, but is usually used. Any solvent may be used as long as it can dissolve the episulfide compound, but ether, toluene, benzene, preferably toluene, which are easily separated from water, are preferably used. Therefore, washing with water is usually performed in a state dissolved in toluene, and toluene is removed after completion.

  The conditions for distillation vary depending on the episulfide compound to be used, but any conditions may be used as long as the episulfide compound can be distilled. It is preferably under reduced pressure, more preferably 0.01 to 100 Torr. Although distillation temperature should just be a temperature which does not decompose | disassemble, Preferably it is 20-200 degreeC, More preferably, it is 50 to 150 degreeC.

The polythiol compound used in the composition for optical materials comprising the episulfide compound and the polythiol compound of the present invention includes all polythiol compounds. Specifically, methanedithiol, 1,2-dimercaptoethane, 2, 2-dimercaptopropane, 1,3-dimercaptopropane, 1,2,3-trimercaptopropane, 1,4-dimercaptobutane, 1,6-dimercaptohexane, bis (2-mercaptoethyl) sulfide, 1 , 2-bis (2-mercaptoethylthio) ethane, 1,5-dimercapto-3-oxapentane, 1,8-dimercapto-3,6-dioxaoctane, 2,2-dimethylpropane-1,3-dithiol 3,4-dimethoxybutane-1,2-dithiol, 2-mercaptomethyl-1,3-dimer Ptopropane, 2-mercaptomethyl 1,4-dimercaptopropane, 2- (2-mercaptoethylthio) -1,3-dimercaptopropane, 1,2-bis (2-mercaptoethylthio) -3-mercaptopropane, 1,1,1-tris (mercaptomethyl) propane, tetrakis (mercaptomethyl) methane, 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,7-dimercapto Methyl-1,11-dimercapto-3,6,9-trithiaundecane, 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane 1,1,3,3- Tetrakis (mercaptomethylthio) propane, ethylene glycol bis (2-mercaptoacetate), ethylene glycol vinyl (3-mercaptopropionate), 1,4-butanediol bis (2-mercaptoacetate), 1,4-butanediol bis (3-mercaptopropionate), trimethylolpropane tris (2-mercaptoacetate), Trimethylolpropane tris (3-mercaptopropionate), pentaerythritol tetrakis (2-mercaptoacetate), pentaerythritol tetrakis (3-mercaptopropionate), 1,1-dimercaptocyclohexane, 1,2-dimercaptocyclohexane 1,3-dimercaptocyclohexane, 1,4-dimercaptocyclohexane, 1,3-bis (mercaptomethyl) cyclohexane, 1,4-bis (mercaptomethyl) cyclohexane, 2,5-bis (mercaptomethyl) -1,4-dithiane, 2,5-bis (mercaptoethyl) -1,4-dithiane, 1,2-bis (mercaptomethyl) benzene, 1,3-bis (mercaptomethyl) benzene, 1,4-bis (Mercaptomethyl) benzene, bis (4-mercaptophenyl) sulfide, bis (4-mercaptophenyl) ether, 2,2-bis (4-mercaptophenyl) propane, bis (4-mercaptomethylphenyl) sulfide, bis (4 -Mercaptomethylphenyl) ether, 2,2-bis (4-mercaptomethylphenyl) propane and the like.

  Specific examples of preferable compounds among the above include bis (2-mercaptoethyl) sulfide, pentaerythritol tetrakis (2-mercaptoacetate), pentaerythritol tetrakis (3-mercaptopropionate), 2,5-bis (mercapto). Methyl) -1,4-dithiane, 1,2-bis (2-mercaptoethylthio) -3-mercaptopropane, 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 1, 1,3,3-tetrakis (mercaptomethylthio) propane, 1,3-bis (mercaptomethyl) Benzene, 1,4-bis (mercaptomethyl) include benzene. More specific examples of the compound are bis (2-mercaptoethyl) sulfide and 1,3-bis (mercaptomethyl) benzene, and the most preferable compound is bis (2-mercaptoethyl) sulfide.

  In the composition for optical materials composed of an episulfide compound and a polythiol compound, when the total of the episulfide compound and the polythiol compound is 100 parts by weight, the episulfide compound is usually 70 to 99 parts by weight, preferably 80 to 98 parts by weight. Particularly preferred is 85 to 97 parts by weight.

  The composition for optical materials of the present invention may further contain a polyisocyanate compound. The polyisocyanate compound includes all compounds having a plurality of isocyanate groups. Specifically, diethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, cyclohexane diisocyanate, 1,3-bis ( Isocyanatomethyl) cyclohexane, 1,4-bis (isocyanatomethyl) cyclohexane, isophorone diisocyanate, 2,6-bis (isocyanatomethyl) decahydronaphthalene, lysine triisocyanate, 2,4-tolylene diisocyanate, 2,6 -Tolylene diisocyanate, o-tolidine diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyl ether diisocyanate, -(2'-isocyanatocyclohexyl) propyl isocyanate, tris (phenyl isocyanate) thiophosphate, isopropylidenebis (cyclohexyl isocyanate), 2,2'-bis (4-isocyanatophenyl) propane, triphenylmethane triisocyanate, bis ( Diisocyanatotolyl) phenylmethane, 4,4 ′, 4 ″ -triisocyanate-2,5-dimethoxyphenylamine, 3,3′-dimethoxybenzidine-4,4′-diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 4,4′-diisocyanatobiphenyl, 4,4′-diisocyanate-3,3′-dimethylbiphenyl, dicyclohexylmethane-4,4′-diisocyanate, 1,1 -Methylenebis (4-isocyanatobenzene), 1,1'-methylenebis (3-methyl-4-isocyanatobenzene), m-xylylene diisocyanate, p-xylylene diisocyanate, 1,3-bis (1-isocyanate) -1-methylethyl) benzene, 1,4-bis (1-isocyanato-1-methylethyl) benzene, 1,3-bis (2-isocyanato-2-propyl) benzene, 2,6-bis (isocyanate) Natomethyl) naphthalene, 1,5-naphthalene diisocyanate, bis (isocyanatomethyl) tetrahydrodicyclopentadiene, bis (isocyanatomethyl) dicyclopentadiene, bis (isocyanatomethyl) tetrahydrothiophene, bis (isocyanatomethyl) norbornene, Bis (isocyaner Tomethyl) adamantane, dimer acid diisocyanate, 1,3,5-tri (1-isocyanatohexyl) isocyanuric acid, thiodiethyl diisocyanate, thiodipropyl diisocyanate, thiodihexyl diisocyanate, bis [(4-isocyanatomethyl) phenyl] sulfide 2,5-diisocyanate-1,4-dithiane, 2,5-diisocyanatomethyl-1,4-dithiane, 2,5-diisocyanatomethylthiophene, dithiodiethyl diisocyanate, dithiodipropyl diisocyanate Furthermore, the compound etc. which changed all or one part of the isocyanate group of said isocyanate into the isothiocyanate group can be mentioned. Among the above, polyisocyanates include isocyanates such as dimers, cyclized trimers and adducts of alcohols or thiols by burette type reaction. Specific examples have been shown above, but the polyisocyanate compounds that can be used in the composition for optical materials of the present invention are not limited to these, and these polyisocyanate compounds may be used alone or in combination of two or more. May be used.

  Of these, preferred polyisocyanate compounds are 1,3-bis (isocyanatomethyl) cyclohexane, m-xylylene diisocyanate, bis (isocyanatomethyl) norbornene, 2,5-diisocyanatomethyl-1,4-dithiane. 1,3-bis (1-isocyanato-1-methylethyl) benzene, and the most preferred polyisocyanate compound is m-xylylene diisocyanate.

  The addition amount of the polyisocyanate compound is usually 0.1 to 30 parts by mass, preferably 0.5 to 20 parts by mass, more preferably 1 to 15 parts by mass with respect to the total amount of the composition for optical materials. Part.

  In addition, you may add sulfur to the composition for optical materials of this invention. When sulfur is used, it is preferable to preliminarily react the episulfide compound and sulfur in advance. The conditions for this preliminary polymerization reaction are preferably -10 ° C to 120 ° C for 0.1 to 240 hours, more preferably 0 to 100 ° C for 0.1 to 120 hours, and particularly preferably 20 to 80 ° C for 0 hours. .1 to 60 hours. It is effective to use a catalyst to advance the preliminary reaction, and preferred examples include 2-mercapto-1-methylimidazole, triphenylphosphine, 3,5-dimethylpyrazole, N-cyclohexyl-2-benzothia. Zolylsulfinamide, dipentamethylene thiuram tetrasulfide, tetrabutyl thiuram disulfide, tetraethyl thiuram disulfide, 1,2,3-triphenylguanidine, 1,3-diphenylguanidine, 1,1,3,3-tetramethyleneguanidine Aminoguanidine urea, trimethylthiourea, tetraethylthiourea, dimethylethylthiourea, zinc dibutyldithiocarbamate, zinc dibenzyldithiocarbamate, zinc diethyldithiocarbamate, zinc dimethyldithiocarbamate, Cholyl dithiocarbamate Pipekoriumu the like. Further, it is preferable to consume 10% or more of sulfur by this preliminary polymerization reaction (100% before reaction), and more preferably 20% or more. The preliminary reaction may be performed under any atmosphere such as air, inert gas such as nitrogen, sealed under normal pressure or pressure reduction. It is also possible to use liquid chromatography or a refractometer to detect the progress of the preliminary reaction.

The addition amount of sulfur is usually 0.01 to 40 parts by weight, preferably 0.1 to 30 parts by weight, more preferably 0.5 to 25 parts by weight with respect to the total amount of the composition for optical materials. It is.

  In this invention, it is preferable to deaerate with respect to the composition for optical materials previously. The deaeration treatment is performed under reduced pressure before, during or after mixing the compound capable of reacting with some or all of the composition components, the polymerization catalyst, and the additive. Preferably, it is performed under reduced pressure during or after mixing. The treatment conditions are 0 to 100 ° C. under reduced pressure of 0.001 to 50 torr for 1 minute to 24 hours. The degree of decompression is preferably 0.005 to 25 torr, more preferably 0.01 to 10 torr, and the degree of decompression may be varied within these ranges. The deaeration time is preferably 5 minutes to 18 hours, more preferably 10 minutes to 12 hours. The temperature at the time of deaeration is preferably 5 ° C. to 80 ° C., more preferably 10 ° C. to 60 ° C., and the temperature may be varied within these ranges. In the degassing treatment, renewing the interface of the resin composition by stirring, blowing of gas, vibration by ultrasonic waves or the like is a preferable operation for enhancing the degassing effect. The components removed by the degassing treatment are mainly dissolved gases such as hydrogen sulfide and low-boiling substances such as low molecular weight thiols. The kind of component is not limited.

  Furthermore, by purifying the composition for optical material and / or each raw material before mixing with a filter having a pore size of about 0.05 to 10 μm to purify impurities, the quality of the optical material of the present invention is further improved. It is also preferable from the viewpoint of increasing.

Hereinafter, a method for producing an optical material by polymerizing the composition for optical materials of the present invention will be described.
As the catalyst for polymerizing and curing the composition for optical materials of the present invention, amines, onium salts and phosphine compounds are used. Specific examples include amines, quaternary ammonium salts, quaternary phosphonium salts, tertiary sulfonium salts, secondary iodonium salts, and phosphine compounds. Of these, quaternary ammonium salts, quaternary phosphonium salts, and phosphine compounds having good compatibility with the composition are more preferable, and quaternary phosphonium salts are more preferable. Specific examples of more preferred compounds include quaternary ammonium salts such as tetra-n-butylammonium bromide, tetraphenylammonium bromide, triethylbenzylammonium chloride, cetyldimethylbenzylammonium chloride, 1-n-dodecylpyridinium chloride, tetra- Examples thereof include quaternary phosphonium salts such as n-butylphosphonium bromide and tetraphenylphosphonium bromide, and phosphine compounds such as triphenylphosphine. Of these, more preferred compounds are triethylbenzylammonium chloride and tetra-n-butylphosphonium bromide, and the most preferred compound is tetra-n-butylphosphonium bromide. The polymerization catalyst may be used alone or in combination of two or more.

  The addition amount of the polymerization catalyst varies depending on the components of the composition, the mixing ratio and the polymerization curing method, but is not generally determined, but is usually 0.001 wt% or more and 5 wt% or less with respect to the total amount of the optical material composition, Preferably, 0.01 wt% or more and 1 wt% or less is used, and most preferably 0.01 wt% or more and 0.5 wt% or less is used. When the addition amount of the polymerization catalyst is more than 5 wt%, the refractive index and heat resistance of the cured product may be lowered and coloring may occur. On the other hand, if it is less than 0.001 wt%, it may not be cured sufficiently and heat resistance may be insufficient.

  When the composition for optical material is polymerized and cured, a polymerization regulator can be added as necessary for the purpose of extending the pot life or dispersing the polymerization heat. Preferred compounds as polymerization regulators are halides of silicon, germanium, tin, and antimony, and more preferred compounds are germanium, tin, and antimony chlorides having an alkyl group. More preferred compounds are specifically dibutyltin dichloride, butyltin trichloride, dioctyltin dichloride, octyltin trichloride, dibutyldichlorogermanium, butyltrichlorogermanium, diphenyldichlorogermanium, phenyltrichlorogermanium, triphenylantimony dichloride, and most preferred. A specific example of the compound is dibutyltin dichloride. The polymerization regulator may be used alone or in combination of two or more.

  The addition amount of the polymerization regulator is usually 0.0001 to 5.0 wt%, preferably 0.0005 to 3.0 wt%, more preferably 0.001 based on the total amount of the optical material composition. -2.0 wt%.

  In addition, when the optical material composition of the present invention is polymerized and cured to obtain an optical material, additives such as known antioxidants, ultraviolet absorbers and bluing agents are added to make the resulting material more practical. Of course, it can be improved.

  Preferable examples of the antioxidant include phenol derivatives. Among them, preferred compounds are polyhydric phenols and halogen-substituted phenols, more preferred compounds are catechol, pyrogallol, and alkyl-substituted catechols, and most preferred compounds are catechol and pyrogallol. Preferable examples of the ultraviolet light inhibitor include benzotriazole compounds. Among these, specific examples of preferred compounds include 2- (2-hydroxy-5-methylphenyl) -2H-benzotriazole, 5-chloro-2- (3,5-di-tert-butyl-2-hydroxyphenyl) -2H. -Benzotriazole, 2- (3-tert-butyl-2-hydroxy-5-methylphenyl) -5-chloro-2H-benzotriazole, 2- (3,5-di-tert-pentyl-2-hydroxyphenyl) -2H-benzotriazole, 2- (3,5-di-tert-butyl-2-hydroxyphenyl) -2H-benzotriazole, 2- (2-hydroxy-4-octyloxyphenyl) -2H-benzotriazole, 2 -(2-Hydroxy-5-tert-octylphenyl) -2H-benzotriazole. Preferable examples of the bluing agent include anthraquinone compounds.

  In addition, when the composition for optical materials of the present invention is easily peeled off from the mold during polymerization, a known external and / or internal adhesion improver is used or added to control the adhesion between the obtained cured product and the mold. It is also possible to improve. Examples of the adhesion improving agent include known silane coupling agents and titanate compounds, and these may be used alone or in combination of two or more. The addition amount is usually 0.0001 to 5 wt% with respect to the total amount of the composition for optical materials. Conversely, when the composition of the present invention is difficult to peel off from the mold after polymerization, a known external and / or internal mold release agent may be used or added to improve the mold release properties of the resulting cured product. Is also possible. Release agents include fluorine-based nonionic surfactants, silicon-based nonionic surfactants, phosphate esters, acidic phosphate esters, oxyalkylene-type acidic phosphate esters, alkali metal salts of acidic phosphate esters, and alkalis of oxyalkylene-type acidic phosphate esters. Examples include metal salts, alkali metal salts of higher fatty acids, higher fatty acid esters, paraffins, waxes, higher aliphatic amides, higher aliphatic alcohols, polysiloxanes, aliphatic amine ethylene oxide adducts, and these can be used alone or in two types. A mixture of the above may be used. The addition amount is usually 0.0001 to 5 wt% with respect to the total amount of the composition for optical materials.

  The method for producing an optical material by polymerizing and curing the composition for an optical material of the present invention is as follows in detail. Additives such as the above-mentioned composition components, antioxidants, ultraviolet absorbers, polymerization catalysts, radical polymerization initiators, adhesion improvers, mold release agents, etc., all mixed together in the same container under stirring, Each raw material may be added and mixed in stages, or several components may be mixed separately and then remixed in the same container. Each raw material and auxiliary raw material may be mixed in any order. In mixing, the set temperature, the time required for this, and the like may basically be the conditions under which each component is sufficiently mixed.

  The composition for optical material subjected to the above reaction and treatment is poured into a glass or metal mold, and after the polymerization and curing reaction is advanced by irradiation with active energy rays such as heating or ultraviolet rays, the composition is removed from the mold. . In this way, an optical material is manufactured. The composition for optical material is preferably polymerized and cured by heating to produce an optical material. In this case, the curing time is 0.1 to 200 hours, usually 1 to 100 hours, and the curing temperature is −10 to 160 ° C., usually −10 to 140 ° C. The polymerization can be carried out by holding at a predetermined polymerization temperature for a predetermined time, raising the temperature by 0.1 ° C. to 100 ° C./hour, lowering the temperature by 0.1 ° C. to 100 ° C./hour, and combinations thereof. In addition, in the method for producing an optical material of the present invention, it is preferable to anneal the cured product at a temperature of 50 to 150 ° C. for about 10 minutes to 5 hours after the completion of polymerization in order to remove distortion of the optical material. It is processing. Furthermore, surface treatments such as dyeing, hard coating, impact resistant coating, antireflection and imparting antifogging properties can be performed as necessary.

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. Evaluation was performed by the following method.
Total content of iron, chromium and nickel: The total content of iron, chromium and nickel of the episulfide compound was measured using ICP emission analyzer SPS5520 manufactured by SII Nanotechnology.
Measurement of yellow: A flat plate having a thickness of 5 mm was prepared by the following polymerization methods A to D, and the YI value was measured using a color techno JS555.
The YI value was compared with a flat plate prepared using an episulfide compound having a total content of iron, chromium and nickel of the detection limit (0.1 ppm) or less, and the difference (ΔYI) was 0.1 or less. .About.0.3 was .largecircle., 0.3 to 0.5 was .DELTA. Among the above, ◎ ○ △ was accepted.

(Polymerization method A)
To 100 parts by weight of bis (β-epithiopropyl) sulfide, 0.1 part by weight of tetrabutylphosphonium bromide was added as a polymerization catalyst and mixed uniformly at room temperature, followed by deaeration treatment. Thereafter, the mixture was filtered through a 1 μm PTFE filter, poured into a mold, and heated from 20 ° C. to 100 ° C. over 20 hours for polymerization and curing. Thereafter, the mold was removed to obtain an optical material.

(Polymerization method B)
To a composition comprising 95 parts by weight of bis (β-epithiopropyl) sulfide and 5 parts by weight of bis (2-mercaptoethyl) sulfide, 0.1 part by weight of tetrabutylphosphonium bromide is added as a polymerization catalyst, and uniformly at room temperature. After mixing, deaeration treatment was performed. Thereafter, the mixture was filtered through a 1 μm PTFE filter, poured into a mold, and heated from 20 ° C. to 100 ° C. over 20 hours for polymerization and curing. Thereafter, the mold was removed to obtain an optical material.

(Polymerization method C)
To 77 parts by weight of bis (β-epithiopropyl) sulfide, 14 parts by weight of 1,3-bis (mercaptomethyl) benzene, 9 parts by weight of tetramethylxylylene diisocyanate, 0.2 parts by weight of tetrabutylphosphonium bromide as a polymerization catalyst, After adding 0.05 part by weight of dibutyltin dichloride and uniformly mixing at room temperature, deaeration treatment was performed. Thereafter, the mixture was filtered through a 1 μm PTFE filter, poured into a mold, and heated from 20 ° C. to 100 ° C. over 20 hours for polymerization and curing. Thereafter, the mold was removed to obtain an optical material.

(Polymerization method D)
0.5 parts by weight of mercaptomethylimidazole was added to 79 parts by weight of bis (β-epithiopropyl) sulfide and 14 parts by weight of sulfur, and preliminarily reacted at 60 ° C. After cooling to 20 ° C., a mixture of 7 parts by weight of bis (2-mercaptoethyl) sulfide, 0.2 parts by weight of dibutyltin dichloride and 0.03 parts by weight of triethylbenzylammonium chloride as a polymerization catalyst was added and mixed uniformly. Deaeration treatment was performed. Thereafter, the mixture was filtered through a 1 μm PTFE filter, poured into a mold, and heated from 20 ° C. to 100 ° C. over 20 hours for polymerization and curing. Thereafter, the mold was removed to obtain an optical material.

(Polymerization method E)
80 parts by weight of bis (β-epithiopropyl) sulfide, 6 parts by weight of bis (2-mercaptoethyl) sulfide, 6 parts by weight of pentaerythritol tetrakisthiopropionate, 1 part by weight of sulfur, 7 parts by weight of m-xylylene diisocyanate Tetrabutylphosphonium bromide (0.1 parts by weight) and dibutyltin dichloride (0.05 parts by weight) were added and mixed uniformly at room temperature, followed by deaeration treatment. Thereafter, the mixture was filtered through a 1 μm PTFE filter, poured into a mold, and heated from 20 ° C. to 100 ° C. over 20 hours for polymerization and curing. Thereafter, the mold was removed to obtain an optical material.

(Create blank)
Using bis (β-epithiopropyl) sulfide whose total content of iron, chromium and nickel was below the detection limit (0.1 ppm), a flat plate having a thickness of 5 mm was prepared using the polymerization methods A to E. Produced.

Examples 1-3
Using the bis (β-epithiopropyl) sulfide having the total content of iron, chromium and nickel shown in Table 1, a 5 mm thick flat plate was prepared using the method of polymerization method A, and ΔYI was compared with that of the blank. Asked. The results are summarized in Table 1.

Examples 4-6
A plate having a thickness of 5 mm was prepared using the method of polymerization method B using bis (β-epithiopropyl) sulfide having a total content of iron, chromium and nickel shown in Table 1. Compared with the blank, ΔYI was obtained by comparing with the blank. The results are summarized in Table 1.

Examples 7-9
A bis (β-epithiopropyl) sulfide having a total content of iron, chromium and nickel shown in Table 1 is used to prepare a 5 mm thick flat plate using the method of polymerization method C, and ΔYI is compared with a blank. Asked. The results are summarized in Table 1.

Examples 10-12
Using a bis (β-epithiopropyl) sulfide having a total content of iron, chromium, and nickel shown in Table 2, a plate having a thickness of 5 mm was prepared using the polymerization method D. Compared with the blank, ΔYI was obtained by comparing with the blank. The results are summarized in Table 2.

Examples 13-15
A plate having a thickness of 5 mm was prepared using the method of polymerization method E using bis (β-epithiopropyl) sulfide having a total content of iron, chromium and nickel shown in Table 2. Compared with the blank, ΔYI was obtained by comparing with the blank. The results are summarized in Table 2.

Comparative Example 1
Using a bis (β-epithiopropyl) sulfide having a total content of iron, chromium, and nickel shown in Table 3, a flat plate having a thickness of 5 mm was prepared using the method of polymerization method A. Compared with the blank, ΔYI was obtained by comparing with the blank. The results are summarized in Table 3.

Comparative Example 2
Using a bis (β-epithiopropyl) sulfide having a total content of iron, chromium, and nickel shown in Table 3, a plate having a thickness of 5 mm was prepared using the method of polymerization method B. Compared with the blank, ΔYI was obtained by comparing with the blank. The results are summarized in Table 3.

Comparative Example 3
A plate having a thickness of 5 mm was prepared using the method of polymerization method C using bis (β-epithiopropyl) sulfide having a total content of iron, chromium and nickel shown in Table 3. Compared with the blank, ΔYI was obtained by comparing with the blank. The results are summarized in Table 3.

Comparative Example 4
Using a bis (β-epithiopropyl) sulfide having a total content of iron, chromium, and nickel shown in Table 3, a flat plate having a thickness of 5 mm was prepared using the method of polymerization method D. Compared with the blank, ΔYI was obtained by comparing with the blank. The results are summarized in Table 3.

Comparative Example 5
A plate having a thickness of 5 mm was prepared using the method of polymerization method E using bis (β-epithiopropyl) sulfide having a total content of iron, chromium and nickel shown in Table 3. Compared with the blank, ΔYI was obtained by comparing with the blank. The results are summarized in Table 3.

  In the above-described embodiments, the episulfide compound or the composition containing the same is polymerized by polymerizing the composition for optical materials using the episulfide compound that satisfies the condition that the total content of iron, chromium, and nickel is 0.5 ppm or less. It was possible to prevent yellowing after curing of the composition for optical materials made of a product. Therefore, according to the present invention, prior to the polymerization reaction, it is possible to preliminarily predict the presence or absence of yellowing after polymerization and to judge whether it is good or not, and to selectively produce only an optical material with good properties. For this reason, both effective utilization of the composition for optical materials and manufacture of an excellent optical material are possible.

Claims (1)

  A method for obtaining an episulfide compound raw material for an optical material composition comprising an episulfide compound and a polythiol compound, the total content of iron, chromium and nickel in the episulfide compound being measured, and as a result, iron, chromium and A method in which an episulfide compound having a total nickel content of 1.0 ppm or less is selected and used as an episulfide compound raw material for an optical material composition.