Sekisui Chemical Co., Ltd.

Masahiro Tsuchiya

Yasuyuki Shirasaka

Nobuto Kamiya

Tetsuhiro Kato

Yuuta Katsurayama

The present invention provides an electret sheet that exhibits excellent piezoelectricity even by light stress. The electret sheet of the invention is characterized by including a charged porous sheet, in which the electret sheet has a compressive elastic modulus of 80 to 300 MPa when compressively deformed at 25&#xb0; C. and a 50% compression stress of 120 to 300 kPa at 25&#xb0; C., and thus has the excellent piezoelectricity for light stress and exhibits the excellent piezoelectricity even by light stress (0.5N or less) caused by a pulse wave or a breathing.

Electret sheet

The present invention provides an electret sheet that exhibits excellent piezoelectricity even by light stress. The electret sheet of the invention is characterized by including a charged porous sheet, in which the electret sheet has a compressive elastic modulus of 80 to 300 MPa when compressively deformed at 25&#xb0; C. and a 50% compression stress of 120 to 300 kPa at 25&#xb0; C., and thus has the excellent piezoelectricity for light stress and exhibits the excellent piezoelectricity even by light stress (0.5 N or less) caused by a pulse wave or a breathing.

The present invention provides an electret sheet that retains high piezoelectricity under high-temperature condition. The electret sheet of the invention is characterized by including a charged porous sheet, in which the electret sheet has a volume resistivity of 1.0&#xd7;10&#x3a9;&#xb7;cm or more at 25&#xb0; C. and a dielectric breakdown voltage of 7 kV or more at 25&#xb0; C. The electret sheet preferably having a volume resistivity of 1.0&#xd7;10&#x3a9;&#xb7;cm or more at 37&#xb0; C. and a dielectric breakdown voltage of 7 kV or more at 37&#xb0; C. retains excellent piezoelectricity even after being left under a high-temperature atmosphere over a long period.

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Osaka, Japan

Masahiro Tsuchiya