Patent US3157741A successfully refreshed from Google Patents.
US4335089A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for producing carbon fibers
Assignee: Sumitomo Chemical Co Ltd
•
Filing: 1980-08-29
•
Granted: 1982-06-15
•
Expires: 2000-08-29
Abstract
Abstract A method for the continuous production of carbon fibers from two or more cheese-like articles of organic polymer fibers having yarn ends at the top portion and tail portion, characterized by preliminarily heat-treating the yarn ends of each cheese-like article, connecting the tail end of a cheese-like article with the top end of another cheese-like article in such a manner that connecting loop portions and knot portions are disposed at different positions, and thereafter causing the yarn to pass through heat-treating furnaces.
Inventors
- 👤 Kunio Maruyama
- 👤 Akira Okazaki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 13:06
CPC Classifications
D; D01; D01F; D01F9/00; D01F9/08; D01F9/12; D01F9/14; D01F9/20; D01F9/21; D01F9/22; B; B65; B65H; B65H69/00; B65H69/04; B65H2701/00; B65H2701/30; B65H2701/31; B65H2701/314
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
134 words
A method for the continuous production of carbon fibers from two or more cheese-like articles of organic polymer fibers having yarn ends at the top portion and tail portion, characterized by preliminarily heat-treating the yarn ends of each cheese-like article so that said yarn end portions have a elongation of 5% or more, a tensile strength of 1 gram/denier or more, and a specific gravity of 1.30 to 1.45; connecting the tail end of a cheese-like article with the top end of another cheese-like article in such a manner that the tail and top ends are divided into at least two portions and connected in the form of loop portions and knot portions, said loop portions and knot portions being disposed at different positions; and thereafter causing the yarn to pass through heat-treating furnaces.
Claim 2
Independent Claim
134 words
A method for the continuous production of carbon fibers from two or more cheese-like articles of organic polymer fibers having yarn ends at the top portion and tail portion, characterized by preliminarily heat-treating the yarn ends of each cheese-like article so that said yarn end portions have a elongation of 5% or more, a tensile strength of 1 gram/denier or more, and a specific gravity of 1.30 to 1.45; connecting the tail end of a cheese-like article with the top end of another cheese-like article in such a manner that the tail and top ends are divided into at least two portions and connected in the form of loop portions and knot portions, said loop portions and knot portions being disposed at different positions; and thereafter causing the yarn to pass through heat-treating furnaces.
Claim 3
Dependent Claim
15 words
The method as claimed in claim 1 wherein said organic polymer fibers are polyacrylonitrile fibers.
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) | 1985-06-14 | 1985-12-14 | 1986-06-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-06-14 | 1989-12-14 | 1990-06-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-06-14 | 1993-12-14 | 1994-06-15 | $7700.00 | Window Closed / Lapsed |