| abstract |
The present invention relates to a polyvinyl acetal resin film, comprising a polyvinyl acetal resin material, whereinthe polyvinyl acetal resin film has a thickness of 5 to 350 µm, and satisfies the following Formulae (1) and (2) where, comparing one surface and the other surface, a mean value of the 10-point average roughness of a rougher surface A and a mean value of the 10-point average roughness of a smoother surface B are defined as Rz1(a) µm and Rz2(a) µm, respectively: Rz1a>1.1×Rz2a3>Rz2a a value obtained by dividing the standard deviation of the 10-point average roughness of the surface A by Rz1(a) and a value obtained by dividing the standard deviation of the 10-point average roughness of the surface B by Rz2(a) are each 0 to 0.30,a viscosity of a toluene/ethanol (1:1, mass ratio) solution containing 10%-by-mass of a polyvinyl acetal resin contained in the polyvinyl acetal resin material, which is measured at 20°C and 30 rpm using a Brookfield-type (B-type) viscometer, is 100 to 1,000 mPa·s, andthe amount of a plasticizer in the polyvinyl acetal resin film is 0 to 20% by mass based on a total mass of the polyvinyl acetal resin film. |