Abstract: An object of the present invention is to improve the piezoelectricity of a PVT having the VDF ratio of 82 to 90% represented by a copolymer, in which copolymerization of vinylidene fluoride VDF and trifluoroethylene TrFe is 85 versus 15 (this is written as PVT85/15, and which is excellent in resistance to deformation, and heat resistance, etc. And therefore, it is also to obtain a piezoelectric film having piezoelectricity exceeding a PVT of less than 82 mol % of VDF represented by a PVT75/25, which conventionally shows the highest piezoelectricity, and a method of producing the same. A piezoelectric film is made of a mixture of two kinds (for example, a first copolymer is PVT85/15 and a second copolymer is PVT75/25) having different polymerization ratios of vinylidene fluoride VDF and trifluoroethylene TrFE.

Abstract: An object of the present invention is to improve the piezoelectricity of a PVT having the VDF ratio of 82 to 90% represented by a copolymer, in which copolymerization of vinylidene fluoride VDF and trifluoroethylene TrFe is 85 versus 15 (this is written as PVT85/15, and which is excellent in resistance to deformation, and heat resistance, etc. And therefore, it is also to obtain a piezoelectric film having piezoelectricity exceeding a PVT of less than 82 mol % of VDF represented by a PVT75/25, which conventionally shows the highest piezoelectricity, and a method of producing the same. A piezoelectric film is made of a mixture of two kinds (for example, a first copolymer is PVT85/15 and a second copolymer is PVT75/25) having different polymerization ratios of vinylidene fluoride VDF and trifluoroethylene TrFE.

Abstract: A piezoelectric film which is better in heat and deformation resistant properties than those in the prior art is provided along with a method of manufacture. The film is a piezoelectric film that is composed of a copolymer of vinylidene fluoride and trifluoroethylene, the copolymer having a content of vinylidene fluoride in a range of not less than 82 mol % and not more than 86 mol % and having a molecular weight not less than 600,000. The piezoelectric film is subjected to a heat treatment for crystallization of the copolymer at a temperature ranging from not less than 140° C. to not more than 150° C., and is thereby caused to develop piezoelectric property. The piezoelectric film further has a heat resistance of not less than 140° C. and a breaking distortion of not less than 8% and not more than 55%, and an excellent deformation resistant property.

Abstract: A piezoelectric film which is better in heat and deformation resistant properties than those in the prior art is provided along with a method of manufacture. The film is a piezoelectric film that is composed of a copolymer of vinylidene fluoride and trifluoroethylene, the copolymer having a content of vinylidene fluoride in a range of not less than 82 mol % and not more than 86 mol % and having a molecular weight not less than 600,000. The piezoelectric film is subjected to a heat treatment for crystallization of the copolymer at a temperature ranging from not less than 140° C. to not more than 150° C., and is thereby caused to develop piezoelectric property. The piezoelectric film further has a heat resistance of not less than 140° C. and a breaking distortion of not less than 8% and not more than 55%, and an excellent deformation resistant property.