Polymerizable composition for polythiourethane-based optical material
An embodiment relates to a polymeric composition for a polythiourethane-based optical material, wherein the polymeric composition, comprising a particular additive, may appropriately adjust the reactivity of an isocyanate such that viscosity is maintained low for a predetermined period of time, and thus is capable of preparing a high-quality polythiourethane-based optical material, without a complicated purification process. Moreover, a polythiourethane-based optical material according to an embodiment has not only a uniform refractive index, but also a low yellow index, and thus may be used as a variety of plastic optical lenses, such as an eyeglass lens or a camera lens and the like.
1. A polymeric composition for a polythiourethane-based optical material, the polymeric composition comprising:
(i) a polythiol compound;
(ii) an isocyanate compound;
(iii) an acid component comprising phosphoric acid; and
(iv) a tin-based catalyst,
wherein the polymeric composition comprises the acid component in an amount of 0.1 to 1 part by weight with respect to 100 parts by weight as the sum of the polythiol compound and the isocyanate compound,
wherein the polymeric composition comprises an internal release agent, and
wherein the internal release agent is one or more selected from the group consisting of fluorine-based nonionic surfactants having a perfluoroalkyl group, a hydroxyalkyl group, or a phosphate ester group; silicone-based nonionic surfactants having a dimethylpolysiloxane group, a hydroxyalkyl group, or a phosphate ester group; alkyl-based quaternary ammonium salts; and acidic phosphate esters.
2. The polymeric composition of claim 1 , wherein the polymeric composition exhibits a viscosity (25° C.) of 1,000 cPs or less after being placed at 25° C. for 8 hours.
3. The polymeric composition of claim 1 , wherein the polythiol compound comprises a metal cation impurity, a nitrogen-containing impurity, or a mixture thereof.
4. The polymeric composition of claim 3 , wherein the polythiol compound comprises 100 to 6,000 ppm of the metal cation impurity.
5. The polymeric composition of claim 3 , wherein the metal cation impurity is one or more selected from the group consisting of Ca cations, Mg cations, K cations, and Na cations.
6. The polymeric composition of claim 3 , wherein the polythiol compound comprises 3 to 10 wt % of a nitrogen-containing impurity based on the total weight of the polythiol compound.
7. The polymeric composition of claim 3 , wherein the nitrogen-containing impurity is one or more selected from the group consisting of melamines, ureas, triazines, amides, imides, and imines.
8. A polythiourethane-based compound obtained from the polymeric composition of claim 1 .
9. An optical material molded from the polythiourethane-based compound of claim 8 .
10. The optical material of claim 9 , wherein the optical material is a plastic optical lens.
11. The optical material of claim 9 , wherein the optical material, when measured for chromaticity coordinates, has a yellow index of 6 or less.