Polythiol composition for plastic lens
An embodiment relates to a polythiol composition for a plastic lens. The polythiol composition for a plastic lens according to the embodiment can produce a clear and transparent plastic lens by way of polymerizing such raw materials as a polythiol compound, an isocyanate, a photoactive color correcting agent, and the like, followed by a simple post-process such as irradiation of ultraviolet rays. In addition, since the process for preparing the lens is simple and economical, the lens is advantageously used for manufacturing various plastic lenses such as eyeglass lenses and camera lenses.
1. A process for preparing a polythiourethane-based lens, which comprises:
(1) providing a polymerizable composition comprising an isocyanate compound, a polythiol compound, and a photoactive color correcting agent;
(2) thermally curing the polymerizable composition to produce a polythiourethane-based resin; and
(3) irradiating the polythiourethane-based resin with ultraviolet rays to reduce the yellow index of the polythiourethane-based resin.
2. The process for preparing a polythiourethane-based lens of claim 1 , wherein in the step (2), the polymerizable composition is heated at a rate of 1° C./min to 10° C./min from an initial temperature between about 0° C. and about 30° C.
3. The process for preparing a polythiourethane-based lens of claim 2 , wherein the polymerizable composition is heated to a temperature of 100 to 150° C. and then maintained for 5 to 30 hours.
4. The process for preparing a polythiourethane-based lens of claim 1 , wherein in the step (3), the yellow index of the polythiourethane-based resin after the irradiation of ultraviolet rays is reduced by 0.11 or more.
5. The process for preparing a polythiourethane-based lens of claim 1 , wherein in the step (3), wherein the ultraviolet rays are irradiated at a wavelength of 395 nm to 445 nm in the UVV region at an intensity of 1 J to 3 J.
6. The process for preparing a polythiourethane-based lens of claim 5 , wherein the ultraviolet rays are irradiated for 5 minutes to 50 minutes.