Patent ID: 7147922

Claim:
A resin film comprising a vinylidene fluoride copolymer and an acrylic polymer as essential components, in which a heat of fusion of crystal derived from the vinylidene fluoride copolymer in the resin film is from 15 to 30 J/g when measured with a differential scanning calorimeter, said vinylidene fluoride copolymer is prepared by dispersion polymerization in the presence of a fluorine-containing solvent, and light transmittance at 600 nm of 50 μm thick resin film is not less than 85%, and wherein said vinylidene fluoride copolymer comprises vinylidene fluoride, tetrafluoroethylene and as an optional component, a monomer copolymerizable therewith, and the content of vinylidene fluoride is from 70–98% by mole.