Patent ID: 8642718

Claim:
A composition, which has been prepolymerized and is capable of being subjected to further polymerization, comprising an inorganic compound A having sulfur atom and/or selenium atom, a compound B represented by the following formula 1: wherein m is an integer from 0 to 4, and n is an integer from 0 to 2, a compound C having an aromatic ring and selected from the group consisting of disulfide compounds which are other than the compound B and have one or more disulfide linkages, the inorganic compound A being contained in an amount from 1 to 50 parts by weight and the compound B being contained in an amount from 50 to 99 parts by weight when a total of the inorganic compound A and the compound B is taken as 100 parts by weight, and the compound C being contained in an amount from 1 to 10 parts by weight based on 100 parts by weight in total of the inorganic compound A and the compound B, and 2-mercapto-1-methylimidazole as a catalyst for prepolymerization, the inorganic compound A and the compound B having been subjected to the prepolymerization, the composition having been subjected to deaeration after prepolymerization, and further comprising a catalyst for polymerization in an amount from 0.001 to 5.0 parts by weight based on 100 parts by weight in total of the inorganic compound A and the compound B.