Composition for optical material

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 particularly a composition for an optical material suitable for a plastic lens and the like. The present invention relates to a method for producing a polyurethane-based resin optical material having good optical characteristics by polymerizing a polymerizable composition composed of a polythiol compound and a polyiso (thio) cyanate compound.

The resin optical material is lighter in weight, less likely to crack, and can be dyed than the inorganic optical material. Therefore, in recent years, it has rapidly become widespread in optical materials such as spectacle lenses and camera lenses.

Resins for optical materials are required to have higher performance. Specifically, high refractive index, high Abbe number, low specific gravity, high heat resistance and the like have been required. In response to such demands, various resins for optical materials have been developed and used so far.

Among them, proposals for polyurethane resins have been actively made. Among the polyurethane-based resins, the most representative resin is a resin obtained by reacting a polythiol compound with a polyiso (thio) cyanate compound (see Patent Documents 1 and 2). This resin is colorless and transparent, and has excellent properties such as impact resistance, dyeability, and processability. Above all, the transparency of resin is an indispensable property for a lens.

However, when producing a resin for an optical material, the resin or the optical material obtained by polymerization may turn yellow. Since it is used as a photo-optical material, if it is discolored after curing, it will be all defective and a huge loss will occur. Therefore, there has been a demand for a method that predicts the presence or absence of yellow discoloration after curing at the stage before curing and enables the judgment of quality.

<p><patcit num="1"><text>Japanese Unexamined Patent Publication No. 7-252207</text></patcit><patcit num="2"><text>Japanese Unexamined Patent Publication No. 9-110956</text></patcit></p>

<p>An object to be solved by the present invention is to provide a composition for an optical material containing polythiol, which can predict and discriminate the presence or absence of yellow discoloration after curing at a stage before polymerization curing, and can judge the quality. Is.</p>

<p>As a result of intensive studies in view of such a situation, the present inventors have made a composition for an optical material composed of a polythiol and a polyiso (thio) cyanate compound having a total content of iron, chromium and nickel of 5.0 ppm or less. This solves the present problem and led to the present invention.</p><p> That is, the present invention is as follows. &lt;1&gt; A composition for an optical material comprising a polythiol compound having a total content of iron, chromium, and nickel of 5.0 ppm or less and a polyiso (thio) cyanate compound. &lt;2&gt; Polythiol compounds are 1,2-bis [(2-mercaptoethyl) thio] -3-mercaptopropane, bis (mercaptomethyl) -3,6,9-trithia-1,11-undecandithiol, pentaerythritol. Selected from the group consisting of tetrakis (3-mercaptopropionate), bis (mercaptomethyl) sulfide, 1,3-bis (mercaptomethyl) benzene, and 1,1,3,3-tetrakis (mercaptomethylthio) propane. The composition for an optical material according to &lt;1&gt; above, which is at least one compound. &lt;3&gt; Polyiso (thio) cyanate compounds are 2,5-bis (isocyanatomethyl) -bicyclo [2.2.1] heptane, 2,6-bis (isocyanatomethyl) -bicyclo [2.2.1] heptane, bis (isocyanato) Selected from the group consisting of methyl) cyclohexane, dicyclohexylmethane diisocyanate, isophorone diisocyanate, 1,3-bis (isocyanatomethyl) benzene and α, α, α', α'-tetramethylxylylene diisocyanate. The composition for an optical material according to &lt;1&gt; above, which is at least one compound. &lt;4&gt; An optical material obtained by polymerizing the composition for an optical material described in &lt;1&gt; above. &lt;5&gt; The optical material according to &lt;4&gt; above, which has been annealed after the polymerization of the composition for an optical material. &lt;6&gt; A method for producing a composition for an optical material, which comprises a step of mixing a polythiol compound having a total content of iron, chromium and nickel of 5.0 ppm or less with a polyiso (thio) cyanate compound. is there.</p>

<p>According to the present invention, a composition for an optical material containing a polythiol compound, which is difficult in the prior art, can predict and discriminate the presence or absence of yellow discoloration after curing at the stage before polymerization curing, and can judge the quality. Etc. can be provided.</p>

The polythiol compound used in the present invention is not particularly limited as long as it is a compound having two or more thiol groups in one molecule.

Specific examples of the polythiol compound include methanedithiol, 1,2-ethanedithiol, 1,1-propanedithiol, 1,2-propanedithiol, 1,3-propanedithiol, 2, 2-Propanedithiol, 1,6-hexanedithiol, 1,2,3-propanetrithiol, 1,1-cyclohexanedithiol, 1,2-cyclohexanedithiol, 2,2-dimethylpropane-1,3-dithiol, 3 , 4-Dimethoxybutane-1,2-dithiol, 2-methylcyclohexane-2,3-dithiol, 1,1-bis (mercaptomethyl) cyclohexane, thioannic acid bis (2-mercaptoethyl ester), 2,3-dimercapto -1-propanol (2-mercaptoacetate), 2,3-dimercapto-1-propanol (3-mercaptopropionate), diethyleneglycolbis (2-mercaptoacetate), diethyleneglycolbis (3-mercaptopropionate), 1 , 2-Dimercaptopropyl methyl ether, 2,3-Dimercaptopropyl methyl ether, 2,2-bis ( Mercaptomethyl) -1,3-propanedithiol, bis (2-mercaptoethyl) ether, ethylene glycol bis (2-mercaptoacetate), ethylene glycol bis (3-mercaptopropionate), trimetylolpropanbis (2-mercapto) Aliper polythiol compounds such as acetate), trimerylpropanbis (3-mercaptopropionate), pentaerythritol tetrakis (2-mercaptoacetate, pentaerythritol tetrakis (3-mercaptopropionate), tetrakis (mercaptomethyl) methane;

1,2-Dimercaptobenzene, 1,3-Dimercaptobenzene, 1,4-Dimercaptobenzene, 1,2-bis (mercaptomethyl) benzene, 1,3-bis (mercaptomethyl) benzene, 1,4- Bis (mercaptomethyl) benzene, 1,2-bis (mercaptoethyl) benzene, 1,3-bis (mercaptoethyl) benzene, 1,4-bis (mercaptoethyl) benzene, 1,2,3-trimercaptobenzene, 1,2,4-Trimercaptobenzene, 1,3,5-Trimercaptobenzene, 1,2,3-Tris (mercaptomethyl) benzene, 1,2,4-Tris (mercaptomethyl) benzene, 1,3, 5-Tris (mercaptomethyl) benzene, 1,2,3-tris (mercaptoethyl) benzene, 1,2,4-tris (mercaptoethyl) benzene, 1,3,5-tris (mercaptoethyl) benzene, 2, 5-Toluenedithiol, 3,4-toluenedithiol, 1,3-di (p-methoxyphenyl) propane- Aromatic polythiol compounds such as 2,2-dithiol, 1,3-diphenylpropane-2,2-dithiol, phenylmethane-1,1-dithiol, 2,4-di (p-mercaptophenyl) pentane;

1,2-bis (mercaptoethylthio) benzene, 1,3-bis (mercaptoethylthio) benzene, 1,4-bis (mercaptoethylthio) benzene, 1,2,3-tris (mercaptomethylthio) benzene, 1 , 2,4-Tris (mercaptomethylthio) benzene, 1,3,5-tris (mercaptomethylthio) benzene, 1,2,3-tris (mercaptoethylthio) benzene, 1,2,4-tris (mercaptoethylthio) ) Benzene, 1,3,5-tris (mercaptoethylthio) benzene, etc., and aromatic polythiol compounds containing sulfur atoms in addition to the mercapto groups such as these nuclear alkylated products;

Bis (mercaptomethyl) sulfide, bis (mercaptomethyl) disulfide, bis (mercaptoethyl) sulfide, bis (mercaptoethyl) disulfide, bis (mercaptopropyl) sulfide, bis (mercaptomethylthio) methane, bis (2-mercaptoethylthio) Methan, bis (3-mercaptopropylthio) methane, 1,2-bis (mercaptomethylthio) ethane, 1,2-bis (2-mercaptoethylthio) ethane, 1,2-bis (3-mercaptopropyl) ethane, 1,3-bis (mercaptomethylthio) propane, 1,3-bis (2-mercaptoethylthio) propane, 1,3-bis (3-mercaptopropylthio) propane, 1,2,3-tris (mercaptomethylthio) Propyl, 1,2,3-tris (2-mercaptoethylthio) propane, 1,2,3-tris (3-mercaptopropylthio) propane, 1,2-bis [(2-mercaptoethyl) Thio] -3-mercaptopropane, 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,7-dimercaptomethyl-1,11-dimercapto-3,6, 9-Trithia undecane, 5,7-Dimercaptomethyl-1,11-Dimercapto-3,6,9-Trithia undecane, Bis (mercaptomethyl) -3,6,9-Trithia-1,11 --Undecane dithiol , Tetrakiss ( Mercaptomethylthiomethyl) methane, tetrakis (2-mercaptoethylthiomethyl) methane, tetrakis (3-mercaptopropylthiomethyl) methane, bis (2,3-dimercaptopropyl) sulfide, bis (1,3-dimercaptopropyl) Sulfide, 2,5-dimercapto-1,4-ditian, 2,5-dimercaptomethyl-1,4-ditian, 2,5-dimercaptomethyl-2,5-dimethyl-1,4-ditian, bis ( An aliphatic polythiol compound containing a sulfur atom in addition to a mercapto group such as mercaptomethyl) disulfide, bis (mercaptoethyl) disulfide, and bis (mercaptopropyl) disulfide, and esters of these thioglycolic acid and mercaptopropionic acid;

Hydroxymethyl sulfide bis (2-mercaptoacetate), hydroxymethyl sulfide bis (3-mercaptopropionate), hydroxyethyl sulfide bis (2-mercaptoacetate), hydroxyethyl sulfide bis (3-mercaptopropionate), hydroxypropyl Gulf bis (2-mercaptoacetate), hydroxypropyl sulfide bis (3-mercaptopropionate), hydroxymethyl disulfide bis (2-mercaptoacetate), hydroxymethyl disulfide bis (3-mercaptopropionate), hydroxyethyl disulfide bis (2-Mercaptoacetate), hydroxyethyl disulfidebis (3-mercaptopropionate), hydroxypropyl disulfidebis (2-mercaptoacetate), hydroxypropyl disulfidebis (3-mercaptopropionate) , 2-Mercaptoethyl ether bis (2-mercaptoacetate), 2-Mercaptoethyl ether bis (3-mercaptopropionate), 1,4-ditian-2,5-diolbis (2-mercaptoacetate), 1,4 -Ditian-2,5-diol bis (3-mercaptopropionate), thiodiglycolic acid bis (2-mercaptoethyl ester), thiodipropionic acid bis (2-mercaptoethyl ester), 4,4-thiodibutylate bis (2-Mercaptoethyl ester), dithiodiglycolic acid bis (2-mercaptoethyl ester), dithiodipropionic acid bis (2-mercaptoethyl ester), 4,4-dithiodibutylate bis (2-mercaptoethyl ester), Bis thiodiglycolate (2,3-dimercaptopropyl ester), bis thiodipropionic acid (2,3-dimercaptopropyl ester), bis dithioglycolic acid (2,3-dimercaptopropyl ester), dithiodipropion An aliphatic polythiol compound containing an ester bond with a sulfur atom in addition to other mercapto groups such as bis acid (2,3-dimercaptopropyl ester);

Heterocyclic compounds containing sulfur atoms in addition to mercapto groups such as 3,4-thiophendithiol and 2,5-dimercapto-1,3,4-thiadiazole;

2-Mercaptoethanol, 3-Mercapto-1,2-propanediol, glycerindi (mercaptoacetate), 1-hydroxy-4-mercaptocyclohexane, 2,4-dimercaptophenol, 2-mercaptohydroquinone, 4-mercaptophenol, 3,4-Dimercapto-2-propanol, 1,3-dimercapto-2-propanol, 2,3-dimercapto-1-propanol, 1,2-dimercapto-1,3-butanediol, pentaerythritol tris (3-mercapto) Propionate), pentaerythritol mono (3-mercaptopropionate), pentaerythritol bis (3-mercaptopropionate), pentaerythritol tris (thioglycolate), dipentaerythritol pentakis (3-mercaptopropionate) ), Hydroxymethyl-tris (mercaptoethylthiomethyl) methane, 1-hydroxyethylthio-3-mercaptoethylthiobenzene and other compounds containing a hydroxy group in addition to the mercapto group;

1,1,3,3-tetrakis (mercaptomethylthio) propane, 1,1,2,2-tetrakis (mercaptomethylthio) ethane, 4,6-bis (mercaptomethylthio) -1,3-dithiacyclohexane, 1,1, 1,5,5-tetrakis (mercaptomethylthio) -3-thiapentane, 1,1,6,6-tetrakis (mercaptomethylthio) -3,4-dithiahexane, 2,2-bis (mercaptomethylthio) ethanethiol, 2- (4,5-Dimercapto-2-thiapentyl) -1,3-dithiacyclopentane, 2,2-bis (mercaptomethyl) -1,3-dithiacyclopentane, 2,5-bis (4,4-) Bis (mercaptomethylthio) -2-thiabutyl) -1,4-dithiane, 2,2-bis (mercaptomethylthio) -1,3-propanedithiol, 3-mercaptomethylthio-1,7-dimercapto-2,6-dithiaheptan , 3,6-bis (mercaptomethylthio) -1,9-dimercapto-2,5,8-trithianonan, 4,6-bis (mercaptomethylthio) -1,9-dimercapto-2,5,8-trithianonan, 3 -Mercaptomethylthio-1,6-dimercapto-2,5-dithiahexane, 2- (2,2-bis (mercaptomethylthio) ethyl) -1,3-dithiane, 1,1,9,9-tetrakis (mercaptomethylthio) -5- (3,3-bis (mercaptomethylthio) -1-thiapropyl) 3,7-dithianonane, tris (2,2-bis (mercaptomethylthio) ethyl) methane, tris (4,4-bis (mercaptomethylthio)) -2-thiabutyl) methane, tetrakis (2,2-bis (mercaptomethylthio) ethyl) methane, tetrakis (4,4-bis (mercaptomethylthio) -2-thiabutyl) methane, 3,5,9,11-tetrakis ( Mercaptomethylthio) -1,13-dimercapto-2,6,8,12-tetrathiatridecane, 3,5,9,11,15,17-hexakis (mercaptomethylthio) -1,19-dimercapto-2,6 , 8,12,14,18-Hexadecane nodecane, 9- (2,2-bis (mercaptomethylthio) ethyl) -3,5,13,15-tetrakis (mercaptomethylthio) -1,17-dimercapto-2,6,8,10, 12,16-Hexadecane heptadecane, 3,4,8,9-tetrakis (mercaptomethylthio) -1,11-dimercapto-2,5,7,10-tetrathiaundecane, 3,4,8,9,13 , 14-Hexadecane (Mercaptomethylthio) -1,16-Dimercapto-2,5,7,10,12,15-Hexadecane hexadecane, 8- {Bis (Mercaptomethylthio) Methyl} -3,4,12,13- Tetrax (mercaptomethylthio) -1,15-dimercapto-2,5,7,9,11,14-hexadecane pentadecane, 4,6-bis {3,5-bis (mercaptomethylthio) -7-mercapto-2, 6-Dithiaheptilthio} -1,3-Ditian, 4-{3,5-bis (mercaptomethylthio) -7-mercapto-2,6-dithiaheptilthio} -6-mercaptomethylthio-1,3- Ditian, 1,1-bis {4- (6-mercaptomethylthio) -1,3-dithianylthio} -3,3 bis (mercaptomethylthio) propane, 1,3-bis {4- (6-mercaptomethylthio) -1 , 3-Dithianilthio} -1,3-bis (mercaptomethylthio) propane, 1- {4- (6-mercaptomethylthio) -1,3-dithianilthio} -3- {2,2-bis (mercaptomethylthio) ethyl} -7,9-bis (mercaptomethylthio) -2,4,6,10-tetrathioundecane, 1- {4- (6-mercaptomethylthio) -1,3-dithianilthio} -3- {2-(1, 3-Dithietanyl)} Methyl-7,9-bis (mercaptomethylthio) -2,4,6,10-tetrathioundecane, 1,5-bis {4- (6-mercaptomethylthio) -1,3-dithianylthio} -3- {2- (1,3-dithietanyl)} Methyl-2,4-dithiapentane, 4,6-bis [3- {2- (1,3-dithietanyl)}3-Dithietane)} Methyl-5-mercapto-2,4-dithiapentylthio] -1,3-dithiolane, 4,6-bis {4- (6-mercaptomethylthio) -1,3-dithianilthio} -1 , 3-Dithiane, 4- {4- (6-Mercaptomethylthio) -1,3-Dithianylthio} -6- {4- (6-Mercaptomethylthio) -1,3-Dithianylthio} -1,3-Dithiane, 3 -{2- (1,3-dithietanil)} Methyl-7,9-bis (mercaptomethylthio) -1,11-dimercapto-2,4,6,10-tetrathiandecan, 9- {2- (1,3-) 3-Dithietane)} Methyl-3,5,13,15-Tetrakiss (Mercaptomethylthio) -1,17-Dimercapto-2,6,8,10,12,16-Hexatiaheptadecane, 3-{2-( 1,3-Dithietane)} Methyl-7,9,13,15-Tetrax (mercaptomethylthio) -1,17-dimercapto-2,4,6,10,12,16-hexathiaheptadecane, 3,7- Bis {2- (1,3-dithietanyl)} methyl-1,9-dimercapto-2,4,6,8-tetrathianonan, 4- {3,4,8,9-tetrakis (mercaptomethylthio) -11 -Mercapto-2,5,7,10-Tetrathiane decyl} -5-Mercaptomethylthio-1,3-dithiolane, 4,5-bis {3,4-bis (mercaptomethylthio) -6-Mercapto-2, 5-Dithiane hexylthio} -1,3-dithiolane, 4- {3,4-bis (mercaptomethylthio) -6-mercapto-2,5-dithiahexylthio} -5-mercaptomethylthio-1,3- Dithiolane, 4- {3-bis (mercaptomethylthio) methyl-5,6-bis (mercaptomethylthio) -8-mercapto-2,4,7-trithiaoctyl} -5-mercaptomethylthio-1,3-dithiolane, 2- [bis {3,4-bis (mercaptomethylthio) -6-mercapto-2,5-dithiahexylthio} methyl] -1,3-dithiolane, 2- {3,4-bis (mercaptomethylthio) -6-mercapto-2,5-dithiahexylthio} mercaptomethylthiomethyl-1,3-dithietane, 2- {3,4,8,9-tetrakis (mercaptomethylthio) -11- Mercapto-2,5,7,10-Tetrathiaundecylthio} Mercaptomethylthiomethyl-1,3-dithiolane, 2- {3-bis (mercaptomethylthio) methyl-5,6-bis (mercaptomethylthio) -8- Mercapto-2,4,7-trithiaoctyl} mercaptomethylthiomethyl-1,3-dithiolane, 4,5-bis [1- {2- (1,3-dithietanyl)}-3-mercapto-2-thiapropyl Thio] -1,3-dithiolane, 4- [1- {2- (1,3-dithietanyl)}-3-mercapto-2-thiapropylthio] -5- {1,2-bis (mercaptomethylthio)- 4-Mercapto-3-thiabutylthio} -1,3-dithiolane, 2- [bis {4- (5-mercaptomethylthio-1,3-dithiolanyl) thio}] methyl-1,3-dithietane, 4- {4- (5-Mercaptomethylthio-1,3-dithiolanyl) Thio} -5- [1- {2- (1,3-dithietanyl)}-3-Mercapto-2-thiapropylthio] -1,3-dithiolane, and more Compounds having a dithioacetal or dithioketal skeleton such as these oligomers;3-Dithietane)} -3-Mercapto-2-thiapropylthio] -5- {1,2-bis (mercaptomethylthio) -4-mercapto-3-thiabutylthio} -1,3-dithiolane, 2- [bis { 4- (5-Mercaptomethylthio-1,3-dithiolanyl) thio}] Methyl-1,3-dithietane, 4- {4- (5-Mercaptomethylthio-1,3-dithiolanyl) thio} -5- [1- {2- (1,3-dithietanyl)} -3-mercapto-2-thiapropylthio] -1,3-dithiolane, and compounds having a dithioacetal or dithioketal skeleton such as these oligomers;3-Dithietane)} -3-Mercapto-2-thiapropylthio] -5- {1,2-bis (mercaptomethylthio) -4-mercapto-3-thiabutylthio} -1,3-dithiolane, 2- [bis { 4- (5-Mercaptomethylthio-1,3-dithiolanyl) thio}] Methyl-1,3-dithietane, 4- {4- (5-Mercaptomethylthio-1,3-dithiolanyl) thio} -5- [1- {2- (1,3-dithietanyl)} -3-mercapto-2-thiapropylthio] -1,3-dithiolane, and compounds having a dithioacetal or dithioketal skeleton such as these oligomers;

Tris (mercaptomethylthio) methane, tris (mercaptoethylthio) methane, 1,1,5,5-tetrakis (mercaptomethylthio) -2,4-dithiapentane, bis (4,4-bis (mercaptomethylthio) -1,3 -Dithiabutyl ( Mercaptomethylthio) Methane, Tris (4,4-bis (mercaptomethylthio) -1,3-dithiabutyl) Methane, 2,4,6-Tris (mercaptomethylthio) -1,3,5-trithiacyclohexane, 2,4 -Bis (mercaptomethylthio) -1,3,5-trithiacyclohexane, 1,1,3,3-tetrakis (mercaptomethylthio) -2-thiapropane, bis (mercaptomethyl) methylthio-1,3,5-trithia Cyclohexane, Tris ((4-mercaptomethyl-2,5-dithiacyclohexyl-1-yl) methylthio) methane, 2,4-bis (mercaptomethylthio) -1,3-dithiacyclopentane, 2-mercaptoethylthio -4-Mercaptomethyl-1,3-dithiacyclopentane, 2- (2,3-dimercaptopropylthio) -1,3-dithiacyclopentane, 4-mercaptomethyl-2- (2,3-di) Mercaptopropylthio) -1,3-dithiacyclopentane, 4-mercaptomethyl-2- (1,3-dimercapto-2-propylthio) -1,3-dithiacyclopentane, Tris (2,2-bis) Mercaptomethylthio) -1-thiaethyl) methane, tris (3,3- Bis (mercaptomethylthio) -2-thiapropyl) methane, tris (4,4-bis (mercaptomethylthio) -3-thiabutyl) methane, 2,4,6-tris (3,3-bis (mercaptomethylthio) -2- Thiapropyl) -1,3,5-trithiacyclohexane, tetrakis (3,3-bis (mercaptomethylthio) -2-thiapropyl) methane, etc., and compounds having an orthotrithioate ester skeleton such as these oligomers;

3,3'-di (mercaptomethylthio) -1,5-dimercapto-2,4-dithiapentane, 2,2'-di (mercaptomethylthio) -1,3-dithiacyclopentane, 2,7-di (mercapto) Methyl) -1,4,5,9-tetrathiaspiro [4.4] nonane, 3,9-dimercapto-1,5,7,11-tetrathiaspiro [5.5] undecane, and orthotetrathios such as these oligomers Examples thereof include compounds having a carbonic acid ester skeleton.

However, the polythiol compound is not limited to the above-mentioned exemplary compounds. Further, each of the above exemplified compounds may be used alone or in combination of two or more.

Among the above exemplified compounds, preferable compounds are 1,2-bis [(2-mercaptoethyl) thio] -3-mercaptopropane and bis (mercaptomethyl) -3,6,9-trithia-1,11-undecane. Dithiol, pentaerythritol tetrakis (3-mercaptopropionate), bis (mercaptomethyl) sulfide, 1,3-bis (mercaptomethyl) benzene, 1,1,3,3-tetrakis (mercaptomethylthio) propane.

The total content of iron, chromium, and nickel in the polythiol may be measured by any measuring method as long as the total content of iron, chromium, and nickel can be measured, but it is preferably measured using an ICP emission spectrometer. To do. The measurement is carried out after pretreating polythiol with an acid such as sulfuric acid or nitric acid according to a conventional method. After performing these measurements, polythiol having a total content of iron, chromium, and nickel of 5.0 ppm or less is used. It is preferably 2.0 ppm or less, more preferably 1.0 ppm or less, still more preferably 0.5 ppm or less, and most preferably 0.3 ppm or less.

If the total content of iron, chromium and nickel exceeds 5.0 ppm, the composition containing these polythiols will turn yellow when polymerized and cured, making it unusable. Therefore, by measuring the total content of iron, chromium, and nickel, it is possible to predict and discriminate the presence or absence of yellow discoloration without polymerization curing, and to judge the quality of polythiol.

When the total content of iron, chromium and nickel exceeds 5.0 ppm, it is an effective method to reduce it to 5.0 ppm or less through the refining process. It is also an effective method to further purify the product into a preferable, more preferable, more preferable, and most preferable state. 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 preferable.

Washing with water may or may not use a solvent, but is usually used. As the solvent, any solvent may be used as long as it dissolves the polythiol, but ether, toluene, benzene, preferably toluene, which can be easily separated from water, is preferably used. Therefore, washing with water is usually carried out in a state of being dissolved in toluene, and toluene is removed after completion.

The conditions for distillation differ depending on the polythiol used, but any condition may be used as long as the polythiol can be distilled. It is preferably under reduced pressure, more preferably 0.01 to 100 Torr. The distillation temperature may be a temperature that does not decompose, but is preferably 20 to 200 ° C, more preferably 50 ° C to 150 ° C.

In the present invention, a polyurethane resin for an optical material is produced by polymerizing a polymerizable composition composed of a polythiol compound and a polyiso (thio) cyanate compound.

The polyiso (thio) cyanate compound used in the present invention is not particularly limited as long as it is a compound having two or more iso (thio) cyanate groups in one molecule. In addition, "isocyanate" means "isocyanate or isocyanate".

Specific examples of the polyiso (thio) isocyanate compound include hexamethylene diisocyanate, 2,2-dimethylpentanediisocyanate, 2,2,4-trimethylhexanediisocyanate, butendiisocyanate, and 1,3-butadiene. -1,4-diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, 1,6,11-undecantry isocyanate, 1,3,6-hexamethylene triisocyanate, 1,8-di Isocyanate-4-an aliphatic polyisocyanate compound such as isocyanatomethyloctane, bis (isocyanatoethyl) carbonate, bis (isocyanatoethyl) ether, lysine diisocyanatomethyl ester, lysine triisocyanate;

2,5-bis (isocyanatomethyl) -bicyclo [2.2.1] heptane, 2,6-bis (isocyanatomethyl) -bicyclo [2.2.1] heptane, bis (isocyanatomethyl) cyclohexane, dicyclohexylmethane diisosia Alicyclic polyisocyanate compounds such as nat, isophorone diisocyanate;

1,2-diisocyanatobenzene, 1,3-diisocyanatobenzene, 1,4-diisocyanatobenzene, 2,4-diisocyanatotoluene, ethylphenylenediisocyanate, isopropylphenylenediisocyanate, dimethylpheni Range isocyanate, diethylphenylenediisocyanate, diisopropylphenylenediisocyanate, trimethylbenzenetriisocyanate, benzenetriisocyanate, biphenyldiisocyanate, toluidine diisocyanate, 4,4'-methylenebis (phenylisocyanate), 4 , 4'-methylenebis (2-methylphenylisocyanate), bibenzyl-4,4'-diisocyanate, bis (isocyanatophenyl) ethylene, 1,2-bis (isocyanatomethyl) benzene, 1,3-bis (Isocyanatomethyl) benzene, 1,4-bis (isocyanatomethyl) benzene, 1,2-bis (isocyanatoethyl) benzene, 1,3-bis (isocyanatoethyl) benzene, 1,4-bis (isocyanatoethyl) benzene Natoethyl) benzene, 1,2-bis (isocyanatopropyl) benzene, 1,3-bis (isocyanatopropyl) benzene, 1,4-bis (isocyanatopropyl) benzene, α, α, α', α' -Tetramethylxylylene diisocyanate, bis (isocyanatobutyl) benzene, bis (isocyanatomethyl) naphthalin, bis (isocyanatomethylphenyl) ether, bis (isocyanatoethyl) phthalate, 2,6-di (isocyanatomethyl) ) Polyisocyanate compounds having aromatic ring compounds such as furan;

Bis (isocyanatomethyl) sulfide, bis (isocyanatoethyl) sulfide, bis (isocyanatopropyl) sulfide, bis (isocyanatohexyl) sulfide, bis (isocyanatomethyl) sulfone, bis (isocyanatomethyl) disulfide, bis (isocyanatomethyl) Isocyanatoethyl) disulfide, bis (isocyanatopropyl) disulfide, bis (isocyanatomethylthio) methane, bis (isocyanatoethylthio) methane, bis (isocyanatomethylthio) ethane, bis (isocyanatoethylthio) ethane, 1, 5-Diisocyanato-2-Isocyanatomethyl-3-thiapentane, 1,2,3-Tris (isocyanatomethylthio) propane, 1, 2,3-Tris (isocyanatoethylthio) propane, 3,5-dithia-1 , 2,6,7-Heptane tetraisocyanate, 2,6-diisocyanatomethyl-3,5-dithia-1,7-heptane diisocyanate, 2,5-diisocyanate methylthiophene, isocyanato ethylthio Sulfur-containing aliphatic polyisocyanate compounds such as -2,6-dithia-1,8-octanediisocyanate;

Aromatic sulfide-based polyisocyanate compounds such as 2-isocyanatophenyl-4-isocyanatophenyl sulfide, bis (4-isocyanatophenyl) sulfide, and bis (4-isocyanatomethylphenyl) sulfide;

Bis (4-isocyanatophenyl) disulfide, bis (2-methyl-5-isocyanatophenyl) disulfide, bis (3-methyl-5-isocyanatophenyl) disulfide, bis (3-methyl-6-isocyanatophenyl) Aromatic disulfide-based polyisocyanate compounds such as disulfide, bis (4-methyl-5-isocyanatophenyl) disulfide, bis (4-methoxy-3-isocyanatophenyl) disulfide;

2,5-Diisocyanatotetrahydrothiophene, 2,5-Diisocyanatomethyltetrahydrothiophene, 3,4-Diisocyanatomethyltetrahydrothiophene, 2,5-Diisocyanato-1,4-dithiane, 2,5-Diisocyanate Natomethyl-1,4-dithiane, 4,5-diisocyanato-1,3-dithiolane, 4,5-bis (isocyanatomethyl) -1,3-dithiolane, 4,5-diisocyanatomethyl-2-methyl Sulfur-containing alicyclic polyisocyanate compounds such as -1,3-dithiolane;

Aromatic polyisothiocianate compounds such as 1,2-diisothiocyanatoethane, 1,6-diisothiocyanatohexane; alicyclic polyisothiocianate compounds such as cyclohexanediisothiocianate; 1,2-di Isothiocyanatobenzene, 1,3-diisothiocyanatobenzene, 1,4-diisothiocianatobenzene, 2,4-diisothiocianatotoluene, 2,5-diisothiocianato-m-xylene, 4, 4'-Methylenebis (Phenylisothiocyanate), 4,4'-Methylenebis (2-Methylphenylisothiocyanate), 4,4'-Methylenebis (3-Methylphenylisothiocianate), 4,4'-Diisoti Aromatic polyisothiocianate compounds such as ossianatobenzophenone, 4,4'-diisothiocianato-3,3'-dimethylbenzophenone, bis (4-isothiocyanatophenyl) ether;

Furthermore, carbonyl polyisoti such as 1,3-benzenedicarbonyldiisothiocianate, 1,4-benzenedicarbonyldiisothiocianate and (2,2-pyridine) -4,4-dicarbonyldiisothiocianate. Oceanate compounds; Sulfur-containing aliphatic polyisothiocianate compounds such as thiobis (3-isothiocianatopropane), thiobis (2-isothiocianatoethane), and dithiobis (2-isothiocianatoethane);

1-Isothiocyanato-4-[(2-isothiocyanato) sulfonyl] Benzene, thiobis (4-isothiocyanatobenzene), sulfonyl (4-isothiocyanatobenzene), dithiobis (4-isothiocyanatobenzene) and other sulfur-containing aromatics Group polyisothiocianate compounds; Sulfur-containing alicyclic polyisothiocianate compounds such as 2,5-diisothiocyanatothiophene, 2,5-diisothiocyanato-1,4-dithiane;

1-Isocyanato-6-Isocyanatohexane, 1-Isocyanato-4-Isocyanatocyclohexane, 1-Isocyanato-4-Isocyanatobenzene, 4-Methyl-3-Isocyanato-1-Isocyanatobenzene, 2- Isocyanato groups such as -4,6-diisothiocyanato-1,3,5-triazine, 4-isocyanatophenyl-4-isocyanatophenyl sulfide, 2-isocyanatoethyl-2-isocyanatoethyl disulfide. And a polyiso (thio) cyanate compound having an isocyanato group.

Further, these chlorine-substituted products, halogen-substituted products such as bromine-substituted products, alkyl-substituted products, alkoxy-substituted products, prepolymer-type modified products with nitro-substituted products and polyhydric alcohols, carbodiimide-modified products, urea-modified products, and burette-modified products. Body, dimerization or trimmerization reaction products and the like can also be used.

However, the polyiso (thio) cyanate compound is not limited to the above-mentioned exemplary compounds. In addition, each of the above exemplified compounds may be used alone or in combination of two or more.

Among the above exemplified compounds, the preferred compounds are 2,5-bis (isocyanatomethyl) -bicyclo [2.2.1] heptane and 2,6-bis (isocyanatomethyl) -bicyclo [2.2.1] heptane, bis. (Isocyanatomethyl) cyclohexane, dicyclohexylmethane diisocyanate, isophorone diisocyanate, 1,3-bis (isocyanatomethyl) benzene and α, α, α', α'-tetramethylxylylene diisocyanate.

The ratio of the polythiol compound to the polyiso (thio) cyanate compound is usually in the range of SH group / NCO (NCS) group = 0.5 to 3.0, preferably 0.6 to 2.0, and more preferably 0.8 to 1.3.

The composition for an optical material of the present invention is a composition containing a polythiol compound and a polyiso (thio) cyanate compound as main components. In addition to this, it is of course possible to further improve the practicality of the obtained material by adding optional components such as a catalyst, an internal mold release agent, an ultraviolet absorber, and a bluing agent, if necessary. For example, a polyurethane-based lens can be produced by injecting a polythiol compound, a polyiso (thio) cyanate compound and, if necessary, an arbitrary component into a lens mold and polymerizing the lens.

A known urethanization catalyst is used as a catalyst for polymerizing and curing the composition for an optical material of the present invention. The amount of the polymerization catalyst added varies depending on the composition, the mixing ratio, and the polymerization curing method, and therefore cannot be unconditionally determined, but is usually 0.001 wt% or more and 5 wt% or less, preferably 0.001 wt% or more and 5 wt% or less, based on the total amount of the composition for optical materials. Is 0.01 wt% or more and 1 wt% or less, most preferably 0.01 wt% or more and 0.5 wt% or less. If the amount of the polymerization catalyst added is more than 5 wt%, the refractive index and heat resistance of the cured product will decrease, and coloring may occur. If it is less than 0.001 wt%, it may not be sufficiently cured and the heat resistance may be insufficient.

Preferred examples of the UV protection agent include benzotriazole compounds. Specific examples of the most preferable compounds are 2- (2-hydroxy-5-methylphenyl) -2H-benzotriazole and 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. Preferred examples of the bluing agent include anthraquinone compounds.

When the composition for optical materials of the present invention is difficult to peel off from the mold after polymerization, a known external and / or internal mold release agent is used or added to improve the mold release property of the obtained cured product. It is also possible to squeeze. The release agent is a fluorine-based nonionic surfactant, a silicon-based nonionic surfactant, a phosphoric acid ester, an acidic phosphoric acid ester, an oxyalkylene type acidic phosphoric acid ester, an alkali metal salt of an acidic phosphoric acid ester, and an alkali of an oxyalkylene type acidic phosphoric acid ester. Metal salts, alkali metal salts of higher fatty acids, higher fatty acid esters, paraffins, waxes, higher aliphatic amides, higher fatty alcohols, polysiloxanes, aliphatic amine ethylene oxide adducts, etc. The above may be mixed and used. The amount added is usually 0.0001 to 5 wt% with respect to the total amount of the composition for optical materials.

Further, for the purpose of improving various physical properties, operability, polymerization reactivity, etc. of polyurethane-based resins, in addition to polythiol compounds and iso (thio) cyanate compounds forming urethane resins, active hydrogen compounds typified by amines and the like, One or more compounds other than the urethane-forming raw material such as an epoxy compound, an olefin compound, a carbonate compound, and an ester compound may be added.

An optical material made of a polyurethane resin is usually produced by cast polymerization. Specifically, the polythiol compound and the polyiso (thio) cyanate compound are mixed. This mixed solution (polymerizable composition) is defoamed by an appropriate method if necessary, then poured into a mold for optical materials, and usually gradually heated from a low temperature to a high temperature for polymerization. Then, the optical material is obtained by demolding.

In the present invention, it is preferable that the composition for an optical material is degassed in advance. The degassing treatment is carried out under reduced pressure before, during or after mixing the compound, the polymerization catalyst and the additive capable of reacting with a part or all of the composition components. Preferably, it is carried out under reduced pressure during or after mixing. The treatment conditions are 0 ° C to 100 ° C for 1 minute to 24 hours under a reduced pressure of 0.001 to 50 torr. 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 degassing time is preferably 5 minutes to 18 hours, more preferably 10 minutes to 12 hours. The temperature at the time of degassing is preferably 5 ° C to 80 ° C, more preferably 10 ° C to 60 ° C, and the temperature may be varied within these ranges. During the degassing treatment, updating the interface of the resin composition by stirring, blowing gas, vibrating by ultrasonic waves, or the like is a preferable operation for enhancing the degassing effect.

Furthermore, purifying these compositions for optical materials and / or each raw material before mixing by filtering impurities and the like with a filter having a pore size of about 0.05 to 10 μm further enhances the quality of the optical material of the present invention. It is also preferable from.

The composition for optical materials that has been subjected to the above-mentioned reaction and treatment is injected into a glass or metal mold, and is removed from the mold after the polymerization curing reaction is promoted by heating or irradiation with active energy rays such as ultraviolet rays. .. In this way, the optical material is manufactured. The composition for an 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 a combination thereof. Further, in the method for producing an optical material of the present invention, after the polymerization is completed, the cured product is annealed at a temperature of 50 to 150 ° C. for about 10 minutes to 5 hours in order to eliminate distortion of the optical material. This is a preferred process.

The polyurethane-based resin produced by the method of the present invention is lightweight, has excellent impact resistance, and has a good hue. Therefore, this resin is suitable for applications of optical materials such as lenses and prisms. In particular, it is very suitable for applications of lenses such as spectacle lenses and camera lenses.

In addition, the optical material is subjected to surface polishing, antistatic treatment, etc. for the purpose of improving antireflection, high hardness, abrasion resistance, chemical resistance, cloud resistance, fashionability, etc., if necessary. Physical and chemical treatments such as hard coating treatment, non-reflective coating treatment, dyeing treatment, and dimming treatment can be performed.

<p> Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited thereto. The evaluation was performed by the following method. Total iron, chromium and nickel content: The total iron, chromium and nickel content of polythiol was measured using an ICP emission spectrometer SPS5520 manufactured by SII Nanotechnology. Measurement of yellow: Flat plates with a thickness of 5 mm were prepared by the following polymerization methods A to D, and the YI value was measured using a colorimeter JS555 manufactured by Color Techno. Comparing the YI values with a flat plate prepared using polythiol having a total content of iron, chromium, and nickel below the detection limit (0.1 ppm), a difference (ΔYI) of 0.1 or less is , 0.1 to 0.3 is , and 0.3. ~ 0.5 was defined as Δ, and 0.5 or more was defined as ×. The above is a pass.</p><p>(Create blank) The total content of iron, chromium and nickel was below the detection limit (0.1 ppm) 1,2-bis [(2-mercaptoethyl) thio] -3-mercaptopropane (hereinafter referred to as compound A), bis (hereinafter referred to as compound A) Using mercaptomethyl) -3,6,9-trithia-1,11-undecandithiol (hereinafter referred to as compound B) and pentaerythritol tetrakis (mercaptopropionate) (hereinafter referred to as compound C), the following A flat plate having a thickness of 5 mm was prepared according to Productions 1 to 4.</p><p>Examples 1 to 3 Using 1,2-bis [(2-mercaptoethyl) thio] -3-mercaptopropane (Compound A) with the total content of iron, chromium and nickel shown in Table 1, according to the following production method 1, the present invention A composition for an optical material and an optical material were prepared and compared with a blank to determine ΔYI. The results are summarized in Table 1.</p><p>Examples 4 to 6 Using the bis (mercaptomethyl) -3,6,9-trithia-1,11-undecanedithiol (compound B) having the total content of iron, chromium and nickel shown in Table 1, the present invention was made according to the following production method 2. The composition for the optical material and the optical material of the above were prepared, and ΔYI was determined by comparing with the blank. The results are summarized in Table 1.</p><p>Examples 7-9 The total iron, chromium, and nickel contents shown in Table 1 are 1,2-bis [(2-mercaptoethyl) thio] -3-mercaptopropane (Compound A), and the iron, chromium, and nickel contents shown in Table 1. The composition and optical material for the optical material of the present invention were prepared using the pentaerythritol tetrakis (mercaptopropionate) (Compound C) of the present invention according to the following production method 3, and ΔYI was determined by comparing with a blank. The results are summarized in Table 1.</p><p>Examples 10-12 Bis (mercaptomethyl) -3,6,9-trithia-1,11-undecandithiol (Compound B) with total iron, chromium and nickel content shown in Table 1 and iron, chromium and nickel shown in Table 1 Using an amount of pentaerythritol tetrakis (mercaptopropionate) (Compound C), the composition and optical material for the optical material of the present invention were prepared according to the following production method 4, and ΔYI was determined by comparing with a blank. The results are summarized in Table 1.</p><p>Comparative example 1 Using 1,2-bis [(2-mercaptoethyl) thio] -3-mercaptopropane (Compound A) with the total content of iron, chromium and nickel shown in Table 1, according to the following production method 1, the present invention A composition for an optical material and an optical material were prepared and compared with a blank to determine ΔYI. The results are summarized in Table 1.</p><p>Comparative example 2 Using the bis (mercaptomethyl) -3,6,9-trithia-1,11-undecanedithiol (compound B) having the total content of iron, chromium and nickel shown in Table 1, the present invention was made according to the following production method 2. The composition for the optical material and the optical material of the above were prepared, and ΔYI was determined by comparing with the blank. The results are summarized in Table 1.</p><p>Comparative example 3 The total iron, chromium, and nickel contents shown in Table 1 are 1,2-bis [(2-mercaptoethyl) thio] -3-mercaptopropane (Compound A), and the iron, chromium, and nickel contents shown in Table 1. The composition and optical material for the optical material of the present invention were prepared according to the following production method 3 using pentaerythritol tetrakis (mercaptopropionate) (Compound C) of the above, and ΔYI was determined. The results are summarized in Table 1.</p><p>Comparative example 4 Bis (mercaptomethyl) -3,6,9-trithia-1,11-undecandithiol (Compound B) with total iron, chromium and nickel content shown in Table 1 and iron, chromium and nickel shown in Table 1 Using an amount of pentaerythritol tetrakis (mercaptopropionate) (Compound C), the composition and optical material for the optical material of the present invention were prepared according to the following production method 4, and ΔYI was determined. The results are summarized in Table 1.</p><p> The details of the manufacturing method used in the above Examples and Comparative Examples are as follows.<u style="single">Manufacturing method 1</u>52 parts by weight of 1,3-bis (isocyanatomethyl) benzene (hereinafter referred to as Compound X) is mixed with 0.05 parts by weight of dibutyltin dichloride and 0.10 parts by weight of dioctyl phosphate as a curing catalyst at 10 to 15 ° C. It was dissolved. Further, 48 parts by weight of 1,2-bis [(2-mercaptoethyl) thio] -3-mercaptopropane (Compound A) was mixed to prepare a uniform solution. After defoaming this mixed uniform solution at 600 Pa for 1 hour, it is filtered through a 1 μm PTFE filter, poured into a mold with a diameter of 70 mm and + 5D, and it takes 24 hours from 40 ° C to 130 ° C. And polymerized. After that, it was demolded to obtain an optical material.</p><p><u style="single">Manufacturing method 2</u>In 1 part by weight of 1,3-bis (isocyanatomethyl) benzene 5 (Compound X), 0.05 part by weight of dibutyltin dichloride and 0.10 part by weight of dioctyl phosphate as a curing catalyst were mixed and dissolved at 10 to 15 ° C. .. Further, 49 parts by weight of bis (mercaptomethyl) -3,6,9-trithia-1,11-undecanedithiol (compound B) was mixed to prepare a uniform solution. After defoaming this mixed uniform solution at 600 Pa for 1 hour, it is filtered through a 1 μm PTFE filter, poured into a mold with a diameter of 70 mm and + 5D, and it takes 24 hours from 40 ° C to 130 ° C. And polymerized. After that, it was demolded to obtain an optical material.</p><p><u style="single">Manufacturing method 3</u>2,5-bis (isocyanatomethyl-bicyclo [2.2.1] heptane and 2,6-bis (isocyanatomethyl-bicyclo [2.2.1] heptane mixture (hereinafter referred to as compound Y)) in 50.6 parts by weight, As a curing catalyst, 0.06 part by weight of dibutyltin dichloride and 0.12 part by weight of dioctyl phosphate were mixed and dissolved at 10 to 15 ° C. Further, 1,2-bis [(2-mercaptoethyl) thio] -3-mercapto 25.5 parts by weight of propane (Compound A) and 23.9 parts by weight of pentaerythritol tetrakis (mercaptopropionate) (Compound C) were mixed to prepare a uniform solution. After defoaming this mixed uniform solution at 600 Pa for 1 hour. , Filtered through a 1 μm PTFE filter, injected into a mold with a diameter of 70 mm and + 5D, polymerized from 40 ° C to 130 ° C for 24 hours, and then demolded to obtain an optical material.</p><p><u style="single">Manufacturing method 4</u>Dibutyl as a curing catalyst in 50.6 parts by weight of a mixture of 2,5-bis (isocyanatomethyl-bicyclo [2.2.1] heptane and 2,6-bis (isocyanatomethyl-bicyclo [2.2.1] heptane (Compound Y)) 0.06 parts by weight of tin dichloride and 0.12 parts by weight of dioctyl phosphate were mixed and dissolved at 10 to 15 ° C. Further, bis (mercaptomethyl) -3,6,9-trithia-1,11-undecandithiol (compound). 25.5 parts by weight of B) and 23.9 parts by weight of pentaerythritol tetrakis (mercaptopropionate) (Compound C) were mixed to prepare a uniform solution. This mixed uniform solution was defoamed at 600 Pa for 1 hour and then 1 μm. The mixture was filtered through the PTFE filter of No. 1 and injected into a mold having a diameter of 70 mm and + 5D, and polymerized from 40 ° C to 130 ° C for 24 hours. Then, the mold was removed to obtain an optical material.</p><p><tables num="1"><img file="JP2012167197A_D0001.tif" /></tables></p><p>In the above-described embodiment, it is possible to prevent yellowing after curing by polymerizing a composition for an optical material using a polythiol that satisfies the condition that the total content of iron, chromium, and nickel is 0.5 ppm or less. did it. Therefore, according to the present invention, it is possible to selectively produce only optical materials having good properties by predicting the presence or absence of yellowing after polymerization and curing and determining the quality before the polymerization reaction. Therefore, both effective utilization of the composition for optical materials and production of excellent optical materials are possible.</p>