PROCESS FOR MAKING UNIFORM HIGH STRENGTH YARNS AND FIBROUS SHEETS

• US 20100078851A1
• Filed: 09/25/2006
• Published: 04/01/2010
• Est. Priority Date: 09/25/2006
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Tan, Chok B., Arvidson, Brian D., Tam, Thomas Y-T.
• Granted Patent: US 7,674,409 B1
• Time in Patent Office: Days
• US Class Current: 264/210.800
• CPC Class Codes: B29C 70/20 oriented in a single direction, e.g. roofing or other parallel fibres B29C70/083, B29C70/226 take precedence
• CPC Class Codes: B29K 2023/00 Use of polyalkenes or derivatives thereof as moulding material
• CPC Class Codes: B29K 2023/0683 UHMWPE, i.e. ultra high molecular weight polyethylene
• CPC Class Codes: B29K 2223/00 Use of polyalkenes or derivatives thereof as reinforcement
• CPC Class Codes: B32B 5/28 impregnated with or embedded in a plastic substance not used
• CPC Class Codes: B65H 2701/31 Textiles threads or artificial strands of filaments
• CPC Class Codes: B65H 2701/38 Thread sheet, e.g. sheet of parallel yarns or wires
• CPC Class Codes: B65H 49/32 Stands or frameworks
• CPC Class Codes: B65H 59/04 by devices acting on package or support
• CPC Class Codes: D02J 1/22 Stretching or tensioning, shrinking or relaxing, e.g. by use of overfeed and underfeed apparatus, or preventing stretch stretch spinning D01D5/12
• CPC Class Codes: D04H 3/04 in rectilinear paths, e.g. crossing at right angles
• CPC Class Codes: F41H 1/02 Armoured or projectile- or missile-resistant garments; Composite protection fabrics F41H5/04 takes precedence
• CPC Class Codes: F41H 5/0485 all the layers being only fibre- or fabric-reinforced layers

Abstract

Methods for preparation of high strength yarns having superior yarn-to-yarn uniformity of denier, tenacity and tensile modulus and uniform unidirectional fibrous sheets. Ballistic composites prepared from these yarns and fibrous sheets have improved uniformity of ballistic resistance.

The drawn yarns, fibrous sheets and articles made therefrom are more uniform than the prior art and are useful in applications requiring impact absorption and ballistic resistance, such as body armor, helmets, breast plates, helicopter seats, spall shields; composite sports equipment such as kayaks, canoes, bicycles and boats; and in fishing line, sails, ropes, sutures and fabrics.

Claims

1. A process for simultaneously drawing multiple ultra-high molecular weight poly(alpha-olefin) (UHMWPO) yarns comprising the steps of:

a) forming a plurality of substantially identical gel-spun multi-filament feed yarns comprising an UHMWPO having an intrinsic viscosity measured in decalin at 135°

C. from 5 dl/g to 45 dl/g, said feed yarns having a tenacity of from 5 g/d to 65 g/d (0.43 GPa to 5.56 GPa) as measured by ASTM D2256-02, a denier of from 100 to 20,000, and the filaments of said yarns being of from 0.5 to 100 denier/filament (0.055 to 11.1 tex/filament);

b) winding up said plurality of feed yarns without imparting twist to the yarns;

c) unrolling the plurality of feed yarns without imparting twist to the yarns, wherein the unrolling torque is substantially the same for each yarn;

d) passing the plurality of feed yarns simultaneously and continuously into, through, and out of an oven, wherein one or more zones are present along the yarn path, said zones having zone temperatures in the range of about 100°

C. to about 165°

C., and wherein the exiting speed of the yarns from the oven is greater than the entrance speed of the yarns into the oven, said yarns being drawn in the oven;

e) cooling the drawn yarns under tension; and

f) winding up a plurality of the drawn yarns without imparting twist thereto.

2. The process of claim 1, wherein said UHMWPO is polyethylene.

3. The process of claim 1, wherein said feed yarns are wound up in a form selected from the group consisting of tube packages and a beam.

4. The process of claim 3, wherein said feed yarns are wound up with tails.

5. The process of claim 3, wherein said feed yarns are wound up with uniform yarn length.

6. The process of claim 1 wherein the plurality of feed yarns is passed into said oven under substantially uniform and constant tension.

7. The process of claim 1, wherein the plurality of drawn yarns are passed out of said oven under substantially uniform tension.

8. The process of claim 1, wherein the drawn yarns are wound up in a form selected from the group consisting of tube packages and beams.

9. The process of claim 1, wherein the drawn yarns are wound up with uniform yarn length.

10. The process of claim 1, wherein the drawn packages are wound at substantially the same tension.

11. The process of claim 1, wherein the drawn yarns are comprised of filaments having a denier/filament of from 0.1 to 20.

12. The process of claim 1, wherein the drawn yarns are comprised of filaments having a denier/filament of from 0.1 to 2.

13. The process of claim 1, wherein from 2 to 1000 feed yarns are drawn simultaneously.

14. The process of claim 1, wherein from 20 to 500 feed yarns are drawn simultaneously.

15. A process for forming a unidirectional fibrous sheet comprising the steps of:

a) selecting a plurality of wound-up multi-filament untwisted high strength yarns from the group consisting of UHMWPO drawn by the process of claim 1, poly(p-phenylene tererephthalamide), poly(p-phenylene-2,6-benzobisoxazole), poly{2,6-diimidazo[4,5-b4′

5′

-e]pyridinylene-1,4(2,5-dihydroxy)phenylene} and their blends and mixtures;

b) unrolling the plurality of high strength yarns without imparting twist to the yarns, wherein the unrolling torque is substantially the same for each yarn;

c) spreading the yarns side-by-side into their constituent filaments to form a unidirectional sheet-like array of substantially parallel filaments;

d) applying a bonding material to the filaments; and

e) consolidating the array of filaments and bonding material into a unitary unidirectional fibrous sheet.

16. The method of claim 15, wherein the high strength yarns are unrolled at substantially the same tension.

17. The method of claim 15, wherein the high strength yarns are unrolled from packages on one or more unrolling creels, each unrolling creel having from 10 to 1000 package positions and the unidirectional fibrous sheet is formed from 10 to 2000 yarns.

18. An article comprising a unidirectional fibrous sheet prepared by the method of claim 15.

19. An article comprising at least two unidirectional sheets as described in claim 18 assembled together surface-to-surface, wherein the direction of the filaments in a sheet is at an angle to the direction of the filaments in adjacent sheets.

20. The article of claim 19, wherein at least two unidirectional sheets are bonded together at their surfaces.

21. The process of claim 1 wherein the unrolling torque is from about 0.6 lb-in (0.07 N-m) to about 1.2 lb-in (0.14 N-m).