CPC H10N 30/857 (2023.02) [C08J 5/18 (2013.01); C08J 7/08 (2013.01); H10N 30/098 (2023.02); C08J 2327/16 (2013.01)] | 3 Claims |
1. A method of producing a piezoelectric body film, the method comprising:
forming a film, the forming including forming a crystalline polymer film having piezoelectricity by subjecting a sheet to stretching treatment and polarization treatment, the sheet being formed from a fluororesin containing a repeating unit derived from vinylidene fluoride as a main constituent unit;
performing relaxation including performing heat fixation and relaxation of residual strain of the crystalline polymer film by subjecting the crystalline polymer film to heating at a first temperature that is not lower than 90° C. and not higher than 115° C. for not less than 5 seconds and not more than 130 seconds; and
performing a secondary heating including subjecting the crystalline polymer film after the performing relaxation to reheating at a temperature that is not lower than the first temperature and not higher than 140° C. for not less than 15 seconds and not more than 120 seconds, and producing the piezoelectric body film.
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