| 摘要 |
PROBLEM TO BE SOLVED: To provide a curable composition with which values of hardness, tensile stress and elongation after accelerated heat curing slightly change with respect to the values at an initial stage of curing, which is particularly effective as a sealing material for construction.SOLUTION: A curable composition includes (a) a polysulfide polyether polymer having in the main chain (i) a polyether moiety represented by -(RO)- (where Ris a 2-4C alkylene group; and n is an integer of 6 to 200) and (ii) structures represented by -CHOCHOCHS- and -CHCH(OH)CHS- (where x is an integer of 1 to 5), and at the terminal, (iii) a polysulfide polyether polymer having two or more thiol groups in one molecule represented by -CHOCHOCH-SH and/or -CHCH(OH)CHSH; and (b) a compound having two or more isocyanate groups in one molecule. The cured product obtained by curing at 70°C for 3.5 hours as the initial curing condition, and additionally curing at 90°C for 24 hours as the heat curing condition exhibits the rate of change in values of hardness (Shore A) under 23°C atmosphere, stress Mat 50% elongation, maximum tensile stress Tand elongation Eat the maximum load in the dumbbell tensile test are each -10 to 10% with respect to the values before heat curing. |
