Claims
- 1. A process for preparing a continuous, substantially uniform tow useful in forming composite molded articles which comprises:
- (a) forming a continuous tow of continuous non-thermoplastic reinforcing fibers;
- (b) forming a continuous tow of continuous thermoplastic polymer fibers having a melting point of at least about 50.degree. C.;
- (c) uniformly and continuously spreading the thermoplastic polymer fiber tow to a selected width;
- (d) uniformly and continuously spreading the non-thermoplastic reinforcing fiber tow to a width that is essentially the same as the selected width for the thermoplastic polymer fiber tow;
- (e) intimately, uniformly and continuously intermixing the spread non-thermoplastic reinforcing fiber tow and the spread thermoplastic polymer fiber tow in a relatively tension-free state by employing a gas intermixing means which directs a generally perpendicular gas flow onto the fibers and by bringing the tows into simultaneous contact with each other in substantially the same area such that there is provided a substantially uniform distribution of the thermoplastic fibers and the non-thermoplastic reinforcing fibers within an intimately intermixed tow; and
- (f) continuously withdrawing the intimately intermixed tow.
- 2. A process for preparing a continuous, substantially uniform tow useful in forming composite molded articles which comprises:
- (a) forming a continuous tow of continuous non-thermoplastic reinforcing fibers;
- (b) forming a continuous tow of continuous thermoplastic polymer fibers having a melting point of at least about 50.degree. C.;
- (c) uniformly and continuously spreading the thermoplastic polymer fiber tow to a selected width;
- (d) uniformly and continuously spreading the non-thermoplastic reinforcing fiber tow to a width that is essentially the same as the selected width for the thermoplastic polymer fiber tow;
- (e) intimately, uniformly and continuously intermixing the spread non-thermoplastic reinforcing fiber tow and the spread thermoplastic polymer fiber tow in a relatively tension-free state by employing a gas box which directs a generally perpendicular gas flow onto the fibers and by bringing the tows into simultaneous contact with each other in substantially the same area such that there is provided a substantially uniform distribution of the thermoplastic fibers and the non-thermoplastic reinforcing fibers within an intimately intermixed tow; and
- (f) continuously withdrawing the intimately intermixed tow.
- 3. The process of claims 1 or 2 wherein the non-thermoplastic reinforcing fibers are formed from the group consisting of metallic, ceramic, amorphous, and polycrystalline fibers.
- 4. The process of claim 3 wherein the non-thermoplastic reinforcing fibers are formed from glass, boron, aramid or ceramic fibers.
- 5. The process of claims 1 or 2 wherein the tow of reinforcing fibers has a bundle denier of about 100 to 100,000.
- 6. The process of claims 1 or 2 wherein the tow of reinforcing fibers has a bundle denier of about 1,000 to 16,000.
- 7. The process of claims 1 or 2 wherein the tow of reinforcing fibers contains about 100 to 300,000 filaments.
- 8. The process of claims 1 or 2 wherein the tow of reinforcing fibers contains about 3,000 to 24,000 filaments.
- 9. The process of claims 1 or 2 wherein the thermoplastic polymer fibers are selected from the group consisting of polyethylene, polypropylene, polyesters, nylons, polyamidimides, polyetherimides, polysulfones, polyether ether ketones and wholly aromatic polyester resins.
- 10. The process of claims 1 or 2 wherein the thermoplastic polymer fibers are liquid crystal polymer fibers.
- 11. The process of claims 1 or 2 wherein the thermoplastic polymer fibers are wholly aromatic polyester fibers.
- 12. The process of claims 1 or 2 wherein the denier of the individual thermoplastic fibers is in the range of about 1 to about 50 and wherein the tow of thermoplastic fibers contains from about 10 to about 150,00 filaments.
- 13. The process of claims 1 or 2 wherein the intimately intermixed tow contains about 10 to about 70 percent by volume of non-thermoplastic reinforcing fibers.
- 14. The process of claim 13 wherein the intimately intermixed tow contains about 20 to about 60 percent by volume of non-thermoplastic reinforcing fibers.
- 15. The process of claim 14 wherein the intimately intermixed tow contains about 60 percent by volume of non-thermoplastic reinforcing fibers.
- 16. The process of claims 1 or 2 wherein the intermixed tow contains about 10 to about 70 percent by volume of non-thermoplastic reinforcing fibers selected from the group consisting of glass, boron and ceramic fibers and wherein the thermoplastic polymer fibers are selected from the group consisting of polyethylene, polypropylene, polyesters, nylons, polyamidimides, polyetherimides, polysulfones, polyether ether ketones and wholly aromatic polyester resins.
Parent Case Info
This is a continuation of co-pending application Ser. No. 589,929 filed on Mar. 15, 1984.
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.
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Continuations (1)
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Number |
Date |
Country |
Parent |
589929 |
Mar 1984 |
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