Piezoelectric pressure-sensitive element and method for making same
First Claim
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1. A piezoelectric pressure-sensitive element which comprises:
- a dispersion of a dipolarly oriented ferroelectric ceramic powder in a cured product made from a composition of (1) an epoxy resin having at least two epoxy groups;
(2), a compound which has at least two amino groups, at least two benzene rings, at least two carbonyl groups and at least two methylene group units, each unit consisting of at least four methylene groups, said amino groups, benzene rings, carbonyl groups and methylene groups being linearly arranged and (3) a crosslinking agent for the epoxy resin, said cured product having dipolarly oriented microcrystals dispersed therein, the microcrystals having been formed during the curing of said composition.
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Abstract
A piezoelectric pressure-sensitive element comprising a dispersion of a dipolarly oriented ferroelectric ceramic powder in a cured product of a composition comprised of an epoxy resin having at least two epoxy groups in the molecules, a compound having defined numbers of amino groups, benzene rings, carbonyl groups and methylene groups, and a crosslinking agent. A methd for making such a piezoelectric pressure-sensitive element is also described, in which the resin composition comprising a ferroelectric ceramic powder is thermally cured and applied with an electric field at a high temperature to cause dipolar orientation of at least the ceramic powder.
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Citations
11 Claims
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1. A piezoelectric pressure-sensitive element which comprises:
- a dispersion of a dipolarly oriented ferroelectric ceramic powder in a cured product made from a composition of (1) an epoxy resin having at least two epoxy groups;
(2), a compound which has at least two amino groups, at least two benzene rings, at least two carbonyl groups and at least two methylene group units, each unit consisting of at least four methylene groups, said amino groups, benzene rings, carbonyl groups and methylene groups being linearly arranged and (3) a crosslinking agent for the epoxy resin, said cured product having dipolarly oriented microcrystals dispersed therein, the microcrystals having been formed during the curing of said composition. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
- a dispersion of a dipolarly oriented ferroelectric ceramic powder in a cured product made from a composition of (1) an epoxy resin having at least two epoxy groups;
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9. A method for making a piezoelectric pressure-sensitive element, the method comprising mixing a composition of (1) an epoxy resin having at least two epoxy groups, (2) a compound which has at least two amino groups, at least two benzene rings, at least two carbonyl groups and at least two methylene group units, each unit consisting of at least 4 methylene groups, said amino grops, benzene rings, carbonyl groups and methylene groups being arranged linearly, and (3) a crosslinking agent for the epoxy resin, with a ferroelectric ceramic powder, thermally curing the mixture by crosslinkage, and applying an electric field to the ceramic powder dispersed in the cured product to cause dipolar orientation, said electric field being not less than 10 kV/cm and applied at a temperature of from 100°
- to 180°
C. - View Dependent Claims (10, 11)
- to 180°
Specification