abstract |
A polyoxyalkylene-modified vinyl acetal polymer including polyoxyalkylene groups represented by formula (I) in the side chains thereof and exhibiting a viscosity-average degree of polymerization (P) of 150-5000, a degree of acetalization of 10-85 mol%, and a polyoxyalkylene substitution rate (S) of 0.1-10 mol%. Polymers such as this exhibit high film strength and plasticity when processed into a film or sheet, and are not susceptible to phase separation when included in a resin composition. [Formula I] (Therein, R 1 represents a hydrogen atom or methyl group, R 2 represents a hydrogen atom or a C1-8 alkyl group, 1 ≤ m ≤ 10, and 3 ≤ n ≤ 20). |