Claims
- 1. A process for preparing tapes from thermoplastic polymers and carbon fibers which comprises:
- (a) spreading a tow of carbon fibers to provide substantially complete wetting of the carbon fibers when impregnated in a crosshead die;
- (b) feeding the tow into a crosshead die;
- (c) impregnating the tow in the crosshead die under pressure with a thermoplastic polymer to form a tape;
- (d) withdrawing the tape from the die; and immediately thereafter;
- (e) cooling the tape with a jet of gas.
- 2. A process for preparing tapes from thermoplastic polymers and carbon fibers which comprises:
- (a) gas jet spreading a tow of carbon fibers;
- (b) feeding the tow into a crosshead die;
- (c) impregnating the row under pressure with a thermoplastic polymer to form a tape;
- (d) withdrawing the tape from the die; and immediately thereafter
- (e) cooling the tape with a jet of gas.
- 3. The process of claim 1 or claim 2 wherein the thermoplastic polymer is selected from the group consisting of polyethylene, polypropylene, polyesters, polyamides, polyimides, polyamidimides, polyetherimides, polysulfones, polyether ether ketones, and wholly aromatic polyester resins.
- 4. The process of claim 1 or claim 2 wherein the thermoplastic polymer is a polyester or copolyester having an I. V. in the range of about 3 to about 6.
- 5. The process of claim 1 or claim 2 wherein the thermoplastic polymer is a liquid crystal polymer.
- 6. The process of claim 1 or claim 2 wherein the thermoplastic polymer is a wholly aromatic polyester.
- 7. The process of claim 1 or claim 2 wherein the carbon fiber is prepared by a first heating step in the range of about 200.degree.-400.degree. C., followed by a second heating step in the range of about 800.degree.-3,000.degree. C. and is based upon polyacrylonitrile polymers and copolymers.
- 8. The process of claim 1 or claim 2 wherein the impregnated tow has a thickness of about 2-20 mils.
- 9. The process of claim 1 or claim 2 wherein the tow contains up to about 200,000 carbon fibers.
- 10. The process of claim 2 wherein the gas jet spreading means comprises a gaseous fed gas box having an adjustable gas metering means and a gas exit port for impinging air upon the moving fiber tow.
- 11. The process of claim 10 wherein the air flow into the air box is in the range of about 40-90 psi, and the exit port is V-shaped and provides gas generally perpendicular to the fiber tow.
- 12. The process of claim 1 or claim 2 wherein the crosshead die includes a fiber diversion path around a stationary spindle, thereby increasing the tension on the carbon fiber tow.
- 13. The process of claim 1 or claim 2 wherein the gas cooling means provides gas both above and below the plane of the extruded tape.
- 14. The process of claim 13 wherein the gas cooling means is a longitudinally extended cylindrical tube.
- 15. The process of claim 14 wherein the tube is equipped with a filter/diffusion screen, thereby providing a relatively uniform flow of cooling gas across the tape.
Government Interests
This invention was made with government support under contract No. NAS1-15749 awarded by the National Aeronautics and Space Administration (NASA). The Government has certain rights in this invention.
US Referenced Citations (11)
Foreign Referenced Citations (6)
Number |
Date |
Country |
2507675 |
Sep 1976 |
DEX |
754321 |
Jan 1971 |
FRX |
48-3536 |
Jan 1973 |
JPX |
51-53020 |
May 1976 |
JPX |
58-36216 |
Mar 1983 |
JPX |
516764 |
Sep 1976 |
SUX |