US4658121A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Self regulating heating device employing positive temperature coefficient of resistance compositions
Assignee: Tyco International Ltd
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Filing: 1985-08-29
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Granted: 1987-04-14
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Expires: 2005-08-29
Abstract
Abstract Disclosed is a positive temperature coefficient of resistance (PTC) crosslinked polymeric composition comprising a first polymeric material exhibiting high green strength prior to crosslinking and elastomeric behavior subsequent to cross-linking, and a second polymeric material comprising a thermoplastic, both said materials having dispersed therein conductive particles, e.g., carbon black, and further, said composition exhibiting a rise in resistance with increased temperature at temperatures above the melting point of either material.
Inventors
- 👤 David A. Horsma
- 👤 Teddy J. Hammack
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 22:07
CPC Classifications
H; H01; H01C; H01C7/00; H01C7/02; H01C7/027; C; C08; C08L; C08L101/00; H01B; H01B1/00; H01B1/20; H01B1/24
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
124 words
A self-regulating heating article comprising at least two electrodes and a crosslinked electrically conductive polymer composition, the electrodes being connectable to a power supply so that current will pass between the electrodes through the conductive polymer composition, said composition having a positive temperature coefficent of resistivity and comprising (1) a first polymeric material which prior to cross-linking exhibits significant green strength corresponding to a tensile stress of at least 10 psi at 20% elongation and which exhibits elastomeric properties at ambient temperatures in the crosslinked state; (2) a second thermoplastic polymer material; and (3) conductive particles which have been dispersed in said polymeric material such that the composition exhibits increased resistance with increased temperatures at temperatures substantially above the melting point of either material.
Claim 2
Dependent Claim
124 words
A self-regulating heating article comprising at least two electrodes and a crosslinked electrically conductive polymer composition, the electrodes being connectable to a power supply so that current will pass between the electrodes through the conductive polymer composition, said composition having a positive temperature coefficent of resistivity and comprising (1) a first polymeric material which prior to cross-linking exhibits significant green strength corresponding to a tensile stress of at least 10 psi at 20% elongation and which exhibits elastomeric properties at ambient temperatures in the crosslinked state; (2) a second thermoplastic polymer material; and (3) conductive particles which have been dispersed in said polymeric material such that the composition exhibits increased resistance with increased temperatures at temperatures substantially above the melting point of either material.
Claim 3
Dependent Claim
12 words
The article of claim 1 wherein the conductive particles are carbon black.
Claim 4
Dependent Claim
21 words
The article of claim 1 wherein the elastomeric and thermoplastic materials are separate segments contained in a graft or block copolymer.
Claim 5
Dependent Claim
19 words
The article of claim 3 wherein the elastomeric material is polytetramethylene oxide and the thermoplastic material is polytetramethylene terephthalate.
Claim 6
Dependent Claim
16 words
The article of claim 3 wherein the elastomeric region provides 30-70% by weight of the copolymer.
Claim 7
Dependent Claim
17 words
The article of claim 1 wherein the elastomeric and thermoplastic materials comprise a physical blend of polymers.
Claim 8
Dependent Claim
18 words
The article of claim 6 wherein the elastomeric material is selected from the group consisting of chlorinated polyethylene.
Claim 9
Dependent Claim
21 words
The article of claim 1 wherein the elastomeric material is an ethylenepropylene rubber and the thermoplastic material is a crystalline polyolefin.
Claim 10
Dependent Claim
20 words
The article of claim 1 wherein the elastomeric material is an ethylenepropylene rubber and the thermoplastic material is a polystyrene.
Claim 11
Dependent Claim
18 words
The article of claim 1 wherein the crosslinked polymeric composition comprises an ethylene-propylene rubber, polypropylene and carbon black.
Claim 12
Dependent Claim
37 words
The article of claim 10 wherein the polypropylene is in the range of from 5 to 40% of the composition, the ethylene-propylene rubber is from 40 to 90% and the carbon black ranges from 5 to 35%.
Claim 13
Dependent Claim
31 words
The article of claim 1 wherein the amount of the elastomeric material is from about 3 to about 75% by weight of the combined weight of elastomeric material and thermoplastic material.
Claim 14
Dependent Claim
27 words
The article of claim 12 wherein the amount of the elastomeric material is from about 4 to about 40% by weight of elastomeric material and thermoplastic material.
Claim 15
Dependent Claim
23 words
The article of claim 1 wherein the amount of the conductive material is from about 4 to 60% by weight of the composition.
Claim 16
Dependent Claim
23 words
The article of claim 14 wherein the amount of the conductive material is from about 5 to 50% by weight of the composition.
Claim 17
Dependent Claim
49 words
The article of claim 1 wherein the amount of the elastomeric material is from about 4 to 40% by weight of the combined weight of the elastomeric material and the thermoplastic material, and the amount of the conductive filler is from 5 to 50% by weight of the composition.
Claim 18
Dependent Claim
12 words
The article of claim 1 which has been cross-linked by ionizing radiation.
Claim 19
Dependent Claim
13 words
The article of claim 1 which has been annealed to obtain minimum resistance.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-04-13 | 1990-10-13 | 1991-04-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-04-13 | 1994-10-13 | 1995-04-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-04-13 | 1998-10-13 | 1999-04-14 | $7700.00 | Window Closed / Lapsed |