US4849133A
Expired / Lapsed
US
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PTC compositions
Assignee: Nippon Mektron KK
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Filing: 1987-02-26
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Granted: 1989-07-18
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Expires: 2007-02-26
Abstract
Abstract A PTC composition comprising at least one polymer, from 5% to 45% by volume of electrically conductive or semiconductive particles having a room temperature electric conductivity of at least 10 2 [s/m] dispersed in said polymer, and from 0.2% to 20% by volume of thermally conductive particles having a room temperature electric conductivity of no more than 10 -3 [s/m] and a thermal conductivity of at least 20 [w/m·k] dispersed in said polymer. A PTC device using such a PTC composition has a high ratio of peak resistance to room temperature resistance, and exhibits high safety.
Inventors
- 👤 Shingo Yoshida
- 👤 Takahisa Akatsuka
- 👤 Osamu Inoue
- 👤 Jiro Toyama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 00:49
CPC Classifications
H; H01; H01C; H01C7/00; H01C7/02; H01C7/027
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
100 words
A PTC composition having a sharply increasing electrical resistance within a narrow temperature range comprising (a) a solid matrix of one or more polymers, (b) 5 to 45% by volume of electrically conductive or semiconductive particles having a room temperature electric conductivity of at least 10 2 (s/m) dispersed in said matrix, and (c) 0.2 to 5% by volume of thermally conductive particles having a room temperature electric conductivity of less than 10 -3 (s/m) and a thermal conductivity of at least about 148 (w/m·k) dispersed in said matrix, wherein the matrix remains a solid throughout the narrow temperature range.
Claim 2
Dependent Claim
100 words
A PTC composition having a sharply increasing electrical resistance within a narrow temperature range comprising (a) a solid matrix of one or more polymers, (b) 5 to 45% by volume of electrically conductive or semiconductive particles having a room temperature electric conductivity of at least 10 2 (s/m) dispersed in said matrix, and (c) 0.2 to 5% by volume of thermally conductive particles having a room temperature electric conductivity of less than 10 -3 (s/m) and a thermal conductivity of at least about 148 (w/m·k) dispersed in said matrix, wherein the matrix remains a solid throughout the narrow temperature range.
Claim 3
Dependent Claim
28 words
The PTC composition according to claim 1 wherein said thermally conductive particles are composed of at least one material selected from the group consisting of silicon, and beryllia.
Claim 4
Dependent Claim
23 words
The PTC composition according to claim 1 wherein said thermally conductive particles have an average particle size of from 1 to 200 micrometers.
Claim 5
Dependent Claim
154 words
A process for preparing a PTC composition having a sharply increasing electrical resistance within a narrow temperature range comprising the steps of (a) preparing a mixture of (1) one or more polymers, (2) 5 to 45% by volume of electrically conductive or semiconductive particles having a room temperature electric conductivity of at least 10 2 (s/m) dispersed in said matrix, and (3) 0.2 to 5% by volume of thermally conductive particles having a room temperature electric conductivity of less than 10 -3 (s/m) and a thermal conductivity of at least about 148 (w/m·k), and (b) kneading the mixture at a temperature ranging from the highest melting point T m of the melting points of the polymers to T m +80° C. to thereby disperse the particles in a matrix of the polymers, wherein the matrix is a solid throughout the narrow temperature range in which the PTC composition has a sharply increasing electrical resistance.
Claim 6
Dependent Claim
154 words
A process for preparing a PTC composition having a sharply increasing electrical resistance within a narrow temperature range comprising the steps of (a) preparing a mixture of (1) one or more polymers, (2) 5 to 45% by volume of electrically conductive or semiconductive particles having a room temperature electric conductivity of at least 10 2 (s/m) dispersed in said matrix, and (3) 0.2 to 5% by volume of thermally conductive particles having a room temperature electric conductivity of less than 10 -3 (s/m) and a thermal conductivity of at least about 148 (w/m·k), and (b) kneading the mixture at a temperature ranging from the highest melting point T m of the melting points of the polymers to T m +80° C. to thereby disperse the particles in a matrix of the polymers, wherein the matrix is a solid throughout the narrow temperature range in which the PTC composition has a sharply increasing electrical resistance.
Claim 7
Dependent Claim
112 words
A PTC device comprising a PTC composition disposed between electrodes, wherein the PTC composition has a sharply increasing electrical resistance within a narrow temperature range and comprises (a) a solid matrix of at least one polymer, (b) 5 to 45% by volume of electrically conductive or semiconductive particles having a room temperature electric conductivity of at least 10 2 (s/m) dispersed in said matrix, and (c) 0.2 to 5% by volume of thermally conductive particles having a room temperature electric conductivity of less than 10 -3 (s/m) and a thermal conductivity of at least about 148 (w/m·k) dispersed in said matrix, wherein the matrix remains a solid throughout the narrow temperature range.
Claim 8
Dependent Claim
112 words
A PTC device comprising a PTC composition disposed between electrodes, wherein the PTC composition has a sharply increasing electrical resistance within a narrow temperature range and comprises (a) a solid matrix of at least one polymer, (b) 5 to 45% by volume of electrically conductive or semiconductive particles having a room temperature electric conductivity of at least 10 2 (s/m) dispersed in said matrix, and (c) 0.2 to 5% by volume of thermally conductive particles having a room temperature electric conductivity of less than 10 -3 (s/m) and a thermal conductivity of at least about 148 (w/m·k) dispersed in said matrix, wherein the matrix remains a solid throughout the narrow temperature range.
Claim 9
Dependent Claim
28 words
The PTC device according to claim 5 wherein said thermally conductive particles are composed of at least one material selected from the group consisting of silicon, and beryllia.
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) | 1992-07-17 | 1993-01-16 | 1993-07-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-07-17 | 1997-01-16 | 1997-07-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-07-17 | 2001-01-16 | 2001-07-18 | $7700.00 | Window Closed / Lapsed |