US4055526A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Planar heating element and production thereof
Assignee: Individual
•
Filing: 1975-03-26
•
Granted: 1977-10-25
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Expires: 1995-03-26
Abstract
Abstract The present invention is related to a method for producing a planar heating element. The method comprises melt-admixing an insulating thermoplastic resin with an electrically conductive powder. The mixture is then extruded, and the extruded body is rapidly cooled.
Inventors
- 👤 Shin Kiyokawa
- 👤 Shokichi Sakaguchi
- 👤 Toru Takeuchi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 09:55
CPC Classifications
H; H05; H05B; H05B3/00; H05B3/40; H05B3/54; H05B3/56; H05B3/10; H05B3/12; H05B3/14; H05B3/146; H05B3/565; Y; Y10; Y10S; Y10S264/00; Y10S264/46
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
80 words
A method for producing a planar heating element which comprises uniformly melt-admixing an insulating thermoplastic resin with an electrically conductive powder wherein said electrically conductive powder is present in an amount less than 40% by weight of the thermoplastic resin, extruding the mixture to form said planar heating element and immediately cooling the extruded heating element rapidly at a temperature of less than 20° C. whereby the conductive powder is in a higher concentration near the surface of the element.
Claim 2
Independent Claim
80 words
A method for producing a planar heating element which comprises uniformly melt-admixing an insulating thermoplastic resin with an electrically conductive powder wherein said electrically conductive powder is present in an amount less than 40% by weight of the thermoplastic resin, extruding the mixture to form said planar heating element and immediately cooling the extruded heating element rapidly at a temperature of less than 20° C. whereby the conductive powder is in a higher concentration near the surface of the element.
Claim 3
Dependent Claim
39 words
The method for producing a planar heating element according to claim 1 in which the insulating thermoplastic resin is selected from the group consisting of polyethylene, poly-propylene, copolymer of ethylene and vinyl acetate, polyvinyl-chloride, polyamide and a mixture thereof.
Claim 4
Dependent Claim
21 words
The method for producing a planar heating element according to claim 1 in which the electrically conductive powder is carbon powder.
Claim 5
Dependent Claim
23 words
The method of claim 1 wherein the amount of the electrically conductive powder is 15% - 20% by weight of the thermoplastic resin.
Claim 6
Dependent Claim
29 words
The method of claim 1 wherein cooling said extruded heating element comprises passing said extruded body through a quenching liquid at 18° C at a rate of 2.5 m/min.
Claim 7
Independent Claim
99 words
A method for producing a planar heating element which comprises uniformly melt-admixing an insulating thermoplastic resin with an electrically conductive powder wherein said electrically conductive powder is present in an amount less than 40% by weight of the thermoplastic resin, extruding the melted mixture to form said planar heating element, applying wires lengthwise into the extruded body, stretching or drafting the extruded body in the softening state and immediately continuously rapidly cooling the extruded body at a temperature of less than 20° C. whereby said electrically conductive powder is in a higher concentration near the surface of the element.
Claim 8
Independent Claim
99 words
A method for producing a planar heating element which comprises uniformly melt-admixing an insulating thermoplastic resin with an electrically conductive powder wherein said electrically conductive powder is present in an amount less than 40% by weight of the thermoplastic resin, extruding the melted mixture to form said planar heating element, applying wires lengthwise into the extruded body, stretching or drafting the extruded body in the softening state and immediately continuously rapidly cooling the extruded body at a temperature of less than 20° C. whereby said electrically conductive powder is in a higher concentration near the surface of the element.
Claim 9
Dependent Claim
30 words
The method of claim 6. wherein said wires are applied to said extruded body by inserting said wires into said extruded body and then pressing said body into a sheet.
Claim 10
Dependent Claim
15 words
The method of claim 7 including subjecting said extruded body to high energy ionizing radiation.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-10-24 | 1981-04-25 | 1981-10-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-10-24 | 1985-04-25 | 1985-10-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-10-24 | 1989-04-25 | 1989-10-25 | $7700.00 | Window Closed / Lapsed |