Polymer composition having positive temperature coefficient characteristics
AssigneeIdemitsu Kosan Co., Ltd.
InventorsMotoi Nishii, Hitoshi Miyake, Hideto Fujii
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Abstract
A polymer composition having positive temperature coefficient characteristics is described, comprising 100 parts by weight of a mixture consisting of from 40 to 90% by weight of a crystalline polymer and from 60 to 10% by weight of an electrically conductive powder and from 10 to 300 parts by weight of a semiconductive inorganic substance. This polymer composition can withstand high voltage and when used as a heat generator, produces a uniform distribution of heat and has a long service life. Thus the polymer composition is useful for production of an overcurrent protecting element and a heat generator.
Claims13
A polymer composition having positive temperature coefficient characteristics, comprising 100 parts by weight of a mixture consisting of from 40 by 90% by weight of a crystalline polymer and from 60 to 10% by weight of an electrically conductive powder having a particle diameter of from 10 to 200 .mu.m and from 10 to 300 parts by weight of a semiconductive inorganic substance having a specific resistance of from 10.sup.-2 to 10.sup.8 ohm-cm and a particle diameter of not more than 300 .mu.m.
A polymer composition having positive temperature coefficient characteristics, comprising 100 parts by weight of a mixture consisting of from 40 to 90% by weight of a crystalline polymer and from 60 to 10% by weight of an electrically conductive powder having a particle diameter of from 10 to 200 .mu.m and from 10 to 300 parts by weight of a semiconductive inorganic substance having a specific resistance of from 10.sup.-2 to 10.sup.8 ohm-cm and a particle diameter of not more than 300 .mu.m;
- said crystalline polymer being high density polyethylene, low density polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinylacetate copolymer, polyamide, polyester or fluorine containing ethylene-based polymers, or a combination thereof;
- said electrically conductive powder being carbon black, graphite, metal powders, powdered carbon fibers or a mixture thereof;
- and
- said semiconductive inorganic substance being silicon carbide, boron carbide or titanium black or a mixture thereof.
Dependencies are inferred from the claim text.