POLYVINYL ACETAL-BASED SPONGE, AND PRODUCTION OF THE POLYVINYL ACETAL-BASED SPONGE

摘要

PROBLEM TO BE SOLVED: To obtain the subject sponge having good elasticity without using an auxiliary such as a surfactant by using a specific modified polyvinyl acetal(PVAt)-based polymer having a part represented by a specified formula as a repeating unit.;SOLUTION: The objective polyvinyl acetal-based sponge has parts represented by formulas I to IV {R1 is a ≥1C alkyl; R2 and R3 are each H or a ≥1C alkyl; (a), b, c and d satisfy equations 0.0002≤(a)/[(a)+b+c+2 d]≤0.008, 0≤b/[(a)+b+c+2d]≤0.15 and 0≤2d/[(a)+b+c+2d]≤0.85} as a repeating unit, preferably 60-5,000 μm average pore diameter of the microporous pores, ≥80 vol.% proportion of the pores and an open cell structure.;COPYRIGHT: (C)2000,JPO