Melt-spun multifilament polyolefin yarn formation processes and yarns formed therefrom
View Patent ↗Disclosed is a method of forming multifilament polyolefin yarns and yarns formed according to the disclosed method. The yarns can be polypropylene yarns and can exhibit any of a high modulus, high tenacity, and a unique crystalline structure for multifilament polyolefin yarns. The process can generally include extruding a polymeric melt including the polyolefin at a relatively high throughput and low spinline tension and quenching the filaments in a liquid bath prior to drawing the fiber bundle at a relatively high draw ratio, for example greater than 10, in some embodiments.
1. A drawn multifilament yarn comprising at least three filaments, each filament including a polyolefin and each filament having a denier of less than about 300 grams/9000 meters, the drawn multifilament yarn having been drawn at a draw ratio of greater than about 6 and the drawn multifilament yarn having a modulus greater than about 40 grams/denier, wherein at least one of the filaments possesses greater than about 80% crystallinity according to WAXS measuring techniques.
2. The drawn multifilament yarn of claim 1 , wherein the yarn has a tenacity greater than about 5 grams/denier.
3. The drawn multifilament yarn of claim 1 , wherein each filament has a denier of between about 0.5 grams/9000 meters and about 100 grams/9000 meters.
4. The drawn multifilament yarn of claim 1 , wherein the polyolefin is a polypropylene.
5. The drawn multifilament yarn of claim 1 , wherein the yarn has a modulus greater than about 100 grams/denier.
6. The drawn multifilament yarn of claim 1 , wherein the yarn has a modulus greater than about 150 grams/denier.
7. The drawn multifilament yarn of claim 1 , wherein the yarn has a tenacity greater than about 7 grams/denier.
8. The drawn multifilament yarn of claim 1 , wherein the yarn exhibits an elongation of less than about 10%.
9. The drawn multifilament yarn of claim 1 , wherein at least one of the filaments has a ratio of equatorial intensity to meridonal intensity greater than about 1.0 according to SAXS measuring techniques.
10. The drawn multifilament yarn of claim 1 , wherein at least one of the filaments has a ratio of equatorial intensity to meridonal intensity greater than about 3.0 according to SAXS measuring techniques.
11. The drawn multifilament yarn of claim 1 , the yarn further comprising a nucleating agent.
12. The drawn multifilament yarn of claim 11 , wherein the nucleating agent is a dibenzylidene sorbitol nucleating agent.
13. A drawn multifilament yarn comprising at least three filaments, each filament including a polyolefin and each filament having a denier of less than about 300 grams/9000 meters, the drawn multifilament yarn having been drawn at a draw ratio of greater than about 6 and the drawn multifilament yarn having a modulus greater than about 40 grams/denier, wherein at least one of the filaments has a ratio of equatorial intensity to meridonal intensity greater than about 1.0 according to SAXS measuring techniques.
14. The drawn multifilament yarn of claim 13 , wherein the yarn has a tenacity greater than about 5 grams/denier.
15. The drawn multifilament yarn of claim 13 , wherein each filament has a denier of between about 0.5 grams/9000 meters and about 100 grams/9000 meters.
16. The drawn multifilament yarn of claim 13 , wherein the polyolefin is a polypropylene.
17. The drawn multifilament yarn of claim 13 , wherein the yarn has a modulus greater than about 100 grams/denier.
18. The drawn multifilament yarn of claim 13 , wherein the yarn has a modulus greater than about 150 grams/denier.
19. The drawn multifilament yarn of claim 13 , wherein the yarn has a tenacity greater than about 7 grams/denier.
20. The drawn multifilament yarn of claim 13 , wherein the yarn exhibits an elongation of less than about 10%.
21. The drawn multifilament yarn of claim 13 , wherein at least one of the filaments has a ratio of equatorial intensity to meridonal intensity greater than about 3.0 according to SAXS measuring techniques.
22. The drawn multifilament yarn of claim 13 , the yarn further comprising a nucleating agent.
23. The drawn multifilament yarn of claim 22 , wherein the nucleating agent is a dibenzylidene sorbitol nucleating agent.