Patent ID: 7309794

Claim:
A method for storing an episulfide compound having in its molecule one or more epithio structural units represented by the formula (1): wherein R 1 is C 1 -C 10 hydrocarbon group; R 2 , R 3 and R 4 are each C 1 -C 10 hydrocarbon group or hydrogen; Y is O, S, Se or Te; n is 0 or 1; and m is 0 or 1, said method comprising the steps of: (a) filtering the episulfide compound at a temperature ranging from its solidifying point to 20° C. using a filter having a pore diameter of 0.05 to 10 μm; and subsequently, (b) storing the episulfide compound at a temperature ranging from its solidification point to 10° C., under light-shielding conditions for at least 60 days while APHA is kept at 20 or lower.