Patent US3615212A successfully refreshed from Google Patents.
US3615212A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of manufacturing carbon fibers
Assignee: Rolls Royce PLC
•
Filing: 1969-03-05
•
Granted: 1971-10-26
•
Expires: 1989-03-05
Abstract
Abstract Polymeric fibers are heated to elevated temperatures in a bed of heated solid particles, as for instance hollow alumina ballotini. The bed is fluidized with a medium such as air as the fibers contact the heated bed. The method is useful to preoxidize or pyrolyze and optionally to postoxidize polymeric fibers such as polyacrylonitrile, ultimately producing carbon fibers of high strength.
Inventors
- 👤 Ian Whitney
- 👤 John William Johnson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 23:05
CPC Classifications
D; D01; D01F; D01F9/00; D01F9/08; D01F9/12; D01F9/14; D01F9/32
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
38 words
The method of claim 1 wherein the improvement comprises heating said solid particles, introducing to said container a fluidizing medium to fluidize said heated solid particles and passing said fiber through said bed of fluidized heated solid particles.
Claim 2
Dependent Claim
107 words
In a method of manufacturing carbon fibers by the pyrolysis of a polymeric fiber comprising the successive steps of: a. preoxidizing said fiber by heating in an oxidizing atmosphere at elevated temperatures; and b. pyrolyzing said fiber thus produced by heating the oxidized fiber at a temperature of up to about at least 1,000* C. for a period of time until substantially all of the fibers constituents except carbon are removed; the improvement wherein at least one of steps (a) and (b) is conducted in contact with a bed of heated solid particles retained in a container and supplied with a fluidizing medium to fluidize said particles.
Claim 3
Dependent Claim
50 words
The method of claim 3 comprising the additional step of: c. postoxidizing said pyrolyzed fiber in an oxidizing atmosphere for a time sufficient to permit surface etching of said fiber; the improvement wherein at least one of steps (a), (b) and (c) is conducted in said bed of heated particles.
Claim 4
Dependent Claim
13 words
The method of claim 3 wherein said solid particles are grains or ballotini.
Claim 5
Dependent Claim
13 words
The method of claim 5 wherein said solid particles are hollow alumina ballotini.
Claim 6
Dependent Claim
19 words
The method of claim 3 wherein step (a) is conducted at a temperature of about 200* to 400* C.
Claim 7
Dependent Claim
15 words
The method of claim 3 wherein step (a) is conducted from one-half to 3 hours.
Claim 8
Dependent Claim
14 words
The method of claim 3 wherein the fiber is stretched while in said bed.
Claim 9
Dependent Claim
46 words
The method of claim 3 wherein step (a) is conducted in said bed of heated particles and said fibers enter the bed by way of a duct which is supplied with hot gas from the bed, so that a temperature gradient is established in said duct.
Claim 10
Dependent Claim
14 words
The method of claim 3 wherein said solid particles are heated by electrical resistance.
Claim 11
Dependent Claim
22 words
The method of claim 3 wherein step (a) is conducted in said bed of heated particles and said fluidizing medium is air.
Claim 12
Dependent Claim
11 words
The method of claim 3 wherein said polymeric fiber is polyacrylonitrile.
Claim 13
Dependent Claim
19 words
The method of claim 4 wherein step (c) is conducted at a temperature of about 400* to 500* C.
Claim 14
Dependent Claim
22 words
The method of claim 4 wherein step (c) is conducted in a bed of heated particles and the fluidizing medium comprises chlorine.
Claim 15
Dependent Claim
11 words
The method of claim 4 wherein said polymeric fiber is polyacrylonitrile.
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) | 1974-10-25 | 1975-04-26 | 1975-10-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-10-25 | 1979-04-26 | 1979-10-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-10-25 | 1983-04-26 | 1983-10-26 | $7700.00 | Window Closed / Lapsed |