Polythiourethane-based plastic lens
Embodiments relate to a polythiourethane-based plastic lens. When a polythiourethane-based plastic lens is polymerized according to the embodiment, the types, contents, and the like of the polythiol compounds and the isocyanate compounds are adjusted to control the storage moduli at room temperature and high temperatures, their variations, the energy attenuation (KEL) obtained therefrom, and the glass transition temperature, whereby the polythiourethane-based plastic lens thus obtained is enhanced in impact resistance and thermal resistance.
1. A polythiourethane-based plastic lens obtained from a polymerizable composition comprising a bi- or higher-functional polythiol compound and a bi- or higher-functional isocyanate compound,
wherein the lens has (i) a ratio of the storage modulus at room temperature (25° C.) to the storage modulus at 70° C. of 1 to 10,
(ii) a storage modulus at room temperature (25° C.) of 100 to 3,000 MPa,
(iii) an energy attenuation (KEL) at room temperature (25° C.) according to the following Equation 1 of 1 to 50, and
(iv) a glass transition temperature (Tg) of 70 to 160° C.:
KEL (energy attenuation)=tan δ×10 12 /[ E ′(@25° C.)×(1+(tan δ) 2 )] [Equation 1]
in the above Equation, E′ (@ 25° C.) is the storage modulus at room temperature (25° C.), and tan δ is the ratio of the loss modulus to the storage modulus at room temperature (25° C.),
wherein the polythiol compound comprises a first polythiol compound and a second polythiol compound different from the first polythiol compound,
wherein the first polythiol compound has a weight average molecular weight of 220 to 1,500 g/mole and is bi-functional to tetra-functional,
wherein the second polythiol compound, which has an ester group at the terminal, has a weight average molecular weight of 400 to 3,000 g/mole and is bi-functional to tetra-functional,
wherein the isocyanate compound is at least one selected from the group consisting of 1,3-bis(isocyanatomethyl)cyclohexane, m-xylene diisocyanate, and 1,3,5-tris(6-isocyanatohexyl)-1,3,5-triazinane-2,4,6-trione, and
wherein the polythiol compound comprises 45 to 70 parts by weight of the first polythiol compound and 50 to 75 parts by weight of the second polythiol compound, based on the total weight of the polythiol compound.
2. The polythiourethane-based plastic lens of claim 1 ,
wherein the first polythiol compound is at least one selected from the group consisting of glycol di(3-mercaptopropionate), 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane, trimethylolpropane tri(3-mercaptopropionate), 4,8-di(mercaptomethyl)-1,11-dimercapto-3,6,9-trithiaundecane, 5,9-di(mercaptoethyl)-1,12-dimercapto-3,7,10-trithiadodecane, and
wherein the second polythiol compound is at least one selected from the group consisting of pentaerythritol tetra(3-mercaptopropionate), pentaerythritol tetra(mercaptoacetate), and
(x, y, and z are each independently an integer from 1 to 10, and x+y+z=20).
3. The polythiourethane-based plastic lens of claim 1 , wherein the isocyanate compound further comprises at least one selected from the group consisting of isophorone diisocyanate, 1,6-diisocyanatohexane, and
bis(4-isocyanatocyclohexyl)methane.
4. The polythiourethane-based plastic lens of claim 1 , wherein the polymerizable composition comprises the polythiol compound and the isocyanate compound at a molar ratio of 20:80 to 80:20.