| abstract |
Provided are: a polymer blend which includes an organic polymer having a reactive silicon-containing group and which can give cured objects excellent in terms of elongation property and stress relaxation; a composition comprising the polymer blend, a specific filler, and a curing catalyst; a sealant comprising the composition; and a sealant for tires. A polymer blend which includes an organic polymer having a bifunctional reactive silicon-containing group of a specific structure is mixed with given proportions of a polyoxyalkylene (A) which has a number-average molecular weight of 13,000 or higher and 100,000 or lower, has a reactive-silicon-containing-group equivalent Eqa of 0.010 mmol/g or more and 0.29 mmol/g or less, and contains more than one silicon-containing group per molecule and a polyoxyalkylene (B) which has a number-average molecular weight of 3,000 or higher and 25,000 or lower, has a reactive-silicon-containing group only at one end, and has a reactive-silicon-containing-group equivalent Eqb of 0.03 mmol/g or more and 0.58 mmol/g or less. |