COMPOSITION FOR OPTICAL MATERIAL

Abstract

A composition for an optical material contains (a) an episulfide compound, (b) a polymerization catalyst, and (c) an ester compound having a halogen at the α position. The (c) ester compound having a halogen at the a position is preferably at least one compound selected from the group consisting of dimethyl chloromalonate, diethyl chloromalonate, dimethyl bromomalonate, and diethyl bromomalonate.

Claims

1. A composition for optical materials containing an episulfide compound (a), a polymerization catalyst (b), and an ester compound having a halogen at a position (c).

2. The composition for optical materials according to claim 1, wherein the episulfide compound (a) is a compound represented by formula (1): ##STR00012## wherein: m represents an integer of 0 to 4; and n represents an integer of 0 to 2.

3. The composition for optical materials according to claim 1, which further comprises a polythiol compound.

4. The composition for optical materials according to claim 1, which further comprises sulfur and/or a compound represented by formula (9): ##STR00013## wherein: X represents S, Se or Te; a to f=0 to 3; 8≥(a+c+e)≥1; 8≥(b+d+f)≥2; and (b+d+f)≥(a+c+e).

5. The composition for optical materials according to claim 1, wherein the ester compound having a halogen at a position (c) is a compound represented by formula (10): ##STR00014## wherein: X represents a halogen; and R.sup.1 and R.sup.2 each independently represent a hydrocarbon having 1 to 10 carbon atoms.

6. The composition for optical materials according to claim 5, wherein the compound represented by formula (10) is at least one compound selected from the group consisting of dimethyl chloromalonate, diethyl chloromalonate, dimethyl bromomalonate and diethyl bromomalonate.

7. An optical material obtained by polymerizing the composition for optical materials according to claim 1.

Description

EXAMPLES

[0055] Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto. Note that evaluation was made according to the below-described methods.

[0056] To compounds (compound (a), sulfur and polythiol compound) shown in Tables 3 and 4 below, triethylbenzyl ammonium chloride as the polymerization catalyst (b) in an amount of 0.03% by mass relative to the total amount of composition for optical materials, and a stabilizer shown in Tables 3 and 4 in an amount of 0.3% by mass relative to the total amount of composition for optical materials were added, the mixture was stirred homogeneously and then kept at 20° C. for 3 hours, and the viscosity thereof was measured using a vibration-type viscometer (VM-10A manufactured by Sekonic Corporation). Specifically, about 30 mL of the solution was put in a 100 mL plastic container, it was allowed to stand in a furnace at 20° C., and the viscosity was measured. The results based on the evaluation criteria shown in Table 1 below are shown in Tables 3 and 4.

TABLE-US-00001 TABLE 1 Evaluation Viscosity (cP) A <350 B 350 to 450 C >450

[0057] To compounds (compound (a), sulfur and polythiol compound) shown in Tables 3 and 4 below, triethylbenzyl ammonium chloride as the polymerization catalyst (b) in an amount of 0.03% by mass relative to the total amount of composition for optical materials, and a stabilizer shown in Tables 3 and 4 in an amount of 0.3% by mass relative to the total amount of composition for optical materials were added, and the mixture was polymerized and cured. Using a weathering test apparatus (Weather-Ometer Ci4000 manufactured by ATLAS), a 48-hour weathering test was conducted at a black panel temperature of 60° C. and at a humidity of 50%, and the change in color tone before and after the weathering test (degree of yellowness (ΔY.I.)) was measured using a spectrophotometric colorimeter CM-5 manufactured by Konica Minolta, Inc. Specifically, Y.I. of a sample (t=5 mm) was measured at 25° C. in advance, the sample was subjected to the above-described weathering test, and after the sample was left in a room at 25° C. for 30 minutes or more, Y.I. of the sample was measured again. Further, the difference in Y.I. before and after the weathering test was defined as ΔY.I. The results based on the evaluation criteria shown in Table 2 below are shown in Tables 3 and 4.

TABLE-US-00002 TABLE 2 Evaluation ΔY.I. A <2.5 B 2.5 to 3.5 C >3.5

TABLE-US-00003 TABLE 3 Compounds Viscosity Weather Examples (weight ratio) Stabilizer (3 hours later) resistance 1 BES/S/BMES = 79/14/7 Dimethyl chloromalonate A A 2 BES/S/BMES = 79/14/7 Diethyl chloromalonate A A 3 BES/S/BMES = 79/14/7 Dimethyl bromomalonate B A 4 BES/S/BMES = 79/14/7 Diethyl bromomalonate B A Compound abbreviations BES: bis(β-epithiopropyl)sulfide S: sulfur BMES: bis(2-mercaptoethyl)sulfide

TABLE-US-00004 TABLE 4 Comparative Compounds Viscosity Weather Examples (weight ratio) Stabilizer (3 hours later) resistance 1 BES/S/BMES = 79/14/7 Dibutyltin dichloride A C 2 BES/S/BMES = 79/14/7 Butyltin trichloride A C 3 BES/S/BMES = 79/14/7 Dimethyldichlorosilane C A 4 BES/S/BMES = 79/14/7 Triethylchlorosilane C B Compound abbreviations BES: bis(β-epithiopropyl)sulfide S: sulfur BMES: bis(2-mercaptoethyl)sulfide