Patent ID: 9458293
Filing Date: 2016-10-04
CPC Classification: C08G,G02B

Claim Text:
1. A method for producing a composition for optical material, starting from 10 to 50 parts by mass of the following compound (a) (provided that it is 10% by mass or more relative to the total mass of the composition for optical material), 50 to 90 parts by mass of the following compound (b), 1 to 50 parts by mass of the following compound (c), and 1 to 50 parts by mass of the following compound (d) (provided that it is 1% by mass or more relative to the total mass of the composition for optical material) (provided that all parts by mass are calculated assuming that the sum of the compound (a) and the compound (b) is set to 100 parts by mass), wherein the method comprises a pre-polymerization reaction between the following compound (a) and the following compound (b) using a hindered amine as a catalyst, and mixing the resulting reaction mixture with the following compound (c) and the following compound (d): (a) an inorganic compound having a sulfur atom; (b) an episulfide compound having one or more episulfide groups per molecule; (c) a thiol compound having one or more mercapto groups per molecule; and (d) an isocyanate compound having one or more isocyanate groups per molecule; wherein compound (a) and compound (b) are substantially completely provided and substantially completely reacted in the pre-polymerization reaction.