POLYVINYLIDENE FLUORIDE RESIN FILM, MULTILAYER FILM, BACKSHEET FOR SOLAR CELL MODULE, AND FILM MANUFACTURING PROCESS

摘要

The invention provides a polyvinylidene fluoride resin (PVDF) film in which a crystal structure determined from an absorbance by an infrared absorption spectrum is such that a proportion of a β-type crystal is 10% or more based on the sum total of an α-type crystal and the β-type crystal, further preferably a film whose tensile modulus in TD at 120°C is 90 MPa or less, or a film in which a ratio of its tensile modulus in TD at a temperature of 100°C to its tensile modulus in TD at a temperature of 23°C is 4% or less, in particular an extruded film, a backsheet for solar cell module, which comprises the film, and a production process of the film, which comprises quenching a PVDF sheet-shaped material melt-extruded at 5 to 70°C and preferably then subjecting the quenched material to a heat treatment.