| abstract |
There is provided a multilayer film comprising a layer (X) containing a polyvinyl acetal (I) having an acetalization degree of 55 to 80 mol %, a content of a vinyl ester monomer unit of 0.1 to 1.5 mol % and a viscosity-average degree of polymerization of 1,400 to 5,000; and a layer (Y) containing a polyvinyl acetal (II) having an acetalization degree of 70 to 85 mol %, a content of a vinyl ester monomer unit of 5 to 15 mol % and a viscosity-average degree of polymerization of 1,400 to 5,000, wherein the multilayer film satisfies formulas (1) and (2): (A−B)/A<0.80 (1) and 1.00×10 −2 <(b/y)/(a/x)<2.00×10 −1 (2). There is thus provided a film which exhibits sufficient sound-absorbability, resistance to coloration by heating, reduction in foreign materials (undissolved materials) and excellent recyclability. |