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US 11,723,280 B2Granted
Electretized film and electronic device
AssigneesMitsui Chemicals, Inc., The School Corporation Kansai University
InventorsYoshiro Tajitsu, Yuzo Nakamura, Tomoya Matayoshi, Takayuki Watanabe, Michio Eriguchi
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Abstract
An electretized film of the present invention includes a cyclic olefin polymer, in which the electretized film is a non-porous film, and a piezoelectric constant d33 in a thickness direction, which is measured by applying a pressing force to the electretized film in the thickness direction, under conditions of a load of 0.5 N, a dynamic load of ±0.25 N, a frequency of 110 Hz, a temperature of 23° C., and a humidity of 50%, is equal to or more than 100 pC/N.
Claims11
An electretized film comprising:
- a cyclic olefin polymer,
- wherein the electretized film is a non-porous film,
- a piezoelectric constant d33 in a thickness direction, which is measured by applying a pressing force to the electretized film in the thickness direction, under conditions of a load of 0.5 N, a dynamic load of ±0.25 N, a frequency of 110 Hz, a temperature of 23° C., and a humidity of 50%, is equal to or more than 100 pC/N, and
- wherein when the electretized film is subjected to a heat resistance test in which the electretized film is allowed to stand in a nitrogen atmosphere at 100° C. for 100 hours, a piezoelectric constant d33 in a thickness direction of the electretized film before the heat resistance test is set as D0, and a piezoelectric constant d33 in the thickness direction of the electretized film after the heat resistance test is set as D1, D1/D0 is equal to or more than 0.60 and equal to or less than 1.1.
1 more element
Dependencies are inferred from the claim text.