Polypropylene yarn having increased Young's modulus and method of making same
The present invention is directed to a monofilament, a yarn, a tape, or a staple fiber, each having 1 to 12,000 Denier per filament, a draw ratio of 2.5:1 to 25:1, and made of a polypropylene composition of a melt blended admixture of about 93% by weight of polypropylene, about 5% by weight of a polypropylene/ethylene copolymer, and about 2 wt. % of an additive. Also, a process for preparing the monofilament, yarn, tape, or staple fiber is disclosed.
1. A monofilament, a yarn, or a tape, each having a draw ratio of about 11.5 to about 25:1 and comprising:
a melt blended admixture of about 94 to about 95% by weight of polypropylene and about 5 to about 6% by weight of a polypropylene/ethylene copolymer having an ethylene content of 8% to 25% by weight of copolymer;
wherein the monofilament, yarn, or tape respectively is a homogenous construction and has a Young's modulus greater than 3.5 GPa.
2. The monofilament, yarn, or tape of claim 1 , wherein each has a tenacity greater than 0.6 g/Denier at 1% strain.
3. A monofilament, a yarn, or a tape, each having a draw ratio of about 11.5 to about 25:1 and comprising:
a melt blended admixture of about 93% by weight of polypropylene, about 5% by weight of a polypropylene/ethylene copolymer having an ethylene content of 8% to 25% by weight of copolymer, and about 2 wt. % of an additive;
wherein the monofilament, yarn, or tape respectively is a homogenous construction and has a Young's modulus greater than 3.5 GPa.
4. The monofilament, yarn, or tape of claim 3 , wherein each has a tenacity greater than 0.6 g/Denier at 1% strain.
5. The monofilament, yarn, or tape of claim 3 , wherein the additive is a colorant, a filler, a delustrant, a thermal stabilizer, an ultraviolet light absorber, an ultraviolet light stabilizer, a terminating agent, an antioxidant, a metal deactivator, a phosphite, a phosphonite, a fluorescent whitening agent, a thiosynergist, a peroxide scavenger, a nucleating agent, a plasticiser, a lubricant, an emulsifier, a rheology additive, a catalyst, a flow-control agent, an optical brightener, a flameproofing agent, an antistatic agent, a blowing agent, a benzofuranone, an indolinone, a hydrophilic agent, a hydrophobic agent, an oliophobic agent, an oliophilic agent, or any combination thereof.
6. The monofilament, yarn, or tape of claim 3 , wherein the additive is carbon black.
7. A process for preparing a slit film tape comprising:
a) preparing a composition comprising about 94 to about 95% by weight of polypropylene and about 5 to about 6% by weight of a polypropylene/ethylene copolymer having an ethylene content of 8% to 25% by weight of copolymer;
b) forming the composition into a film;
c) slitting the film into a tape; and
d) hot-drawing the tape at a temperature below the melting point of the composition and at a draw ratio between about 11.5 and about 25:1 to produce the slit film tape with a homogenous construction and a Young's modulus greater than 3.5 GPa.
8. The process of claim 7 , wherein the draw ratio is about 12:1.
9. The process of claim 7 , further comprising annealing the slit film tape.
10. The process of claim 7 , further comprising fibrillating the slit film tape.
11. A process for preparing a slit film tape comprising:
a) preparing a composition comprising about 93% by weight of polypropylene, about 5% by weight of a polypropylene/ethylene copolymer having an ethylene content of 8% to 25% by weight of copolymer, and about 2 wt. % of an additive;
b) forming the composition into a film;
c) slitting the film into a tape; and
d) hot-drawing the tape at a temperature below the melting point of the composition and at a draw ratio between about 11.5 and about 25:1 to produce the slit film tape with a homogenous construction and a Young's modulus greater than 3.5 GPa.
12. The process of claim 11 , wherein the draw ratio is about 12:1.
13. The process of claim 11 , further comprising annealing the slit film tape.
14. The process of claim 11 , further comprising fibrillating the slit film tape.
15. The process of claim 11 , wherein the additive is a colorant, a filler, a delustrant, a thermal stabilizer, an ultraviolet light absorber, an ultraviolet light stabilizer, a terminating agent, an antioxidant, a metal deactivator, a phosphite, a phosphonite, a fluorescent whitening agent, a thiosynergist, a peroxide scavenger, a nucleating agent, a plasticiser, a lubricant, an emulsifier, a rheology additive, a catalyst, a flow-control agent, an optical brightener, a flameproofing agent, an antistatic agent, a blowing agent, a benzofuranone, an indolinone, a hydrophilic agent, a hydrophobic agent, an oliophobic agent, an oliophilic agent, or any combination thereof.
16. The process of claim 11 , wherein the additive is carbon black.
17. A process for preparing a monofilament comprising:
a) preparing a composition comprising about 94 to about 95% by weight of polypropylene homopolymer and about 5 to about 6% by weight of a polypropylene/ethylene copolymer having an ethylene content of 8% to 25% by weight of copolymer;
b) forming the composition into a filament; and
c) hot-drawing the monofilament at a temperature below the melting point of the homopolymer and at a draw ratio between about 11.5 and about 25:1 to produce the monofilament with a homogenous construction and a Young's modulus greater than 3.5 GPa.
18. A process for preparing a monofilament comprising:
a) preparing a composition comprising about 93% by weight of polypropylene, about 5% by weight of a polypropylene/ethylene copolymer having an ethylene content of 8% to 25% by weight of copolymer, and about 2 wt. % of an additive;
b) forming the composition into a filament; and
c) hot-drawing the monofilament at a temperature below the melting point of the homopolymer and at a draw ratio between about 11.5 and about 25:1 to produce the monofilament with a homogenous construction and a Young's modulus greater than 3.5 GPa.
19. The process of claim 18 , wherein the additive is a colorant, a filler, a delustrant, a thermal stabilizer, an ultraviolet light absorber, an ultraviolet light stabilizer, a terminating agent, an antioxidant, a metal deactivator, a phosphite, a phosphonite, a fluorescent whitening agent, a thiosynergist, a peroxide scavenger, a nucleating agent, a plasticiser, a lubricant, an emulsifier, a rheology additive, a catalyst, a flow-control agent, an optical brightener, a flameproofing agent, an antistatic agent, a blowing agent, a benzofuranone, an indolinone, a hydrophilic agent, a hydrophobic agent, an oliophobic agent, an oliophilic agent, or any combination thereof.
20. The process of claim 18 , wherein the additive is carbon black.
21. A monofilament, a yarn, or a tape, each having a draw ratio of about 11.5 to about 25:1 and a tenacity of at least 0.75 g/Denier at 1% strain, at least 1.5 g/Denier at 2% strain, and at least 3.75 g/Denier at 5% strain, and comprising:
a melt blended admixture of about 94 to about 95% by weight of polypropylene and about 5 to about 6% by weight of a polypropylene/ethylene copolymer having an ethylene content of about 8% to about 25% by weight of copolymer;
wherein the monofilament, yarn, or tape respectively is a homogenous construction.
22. The monofilament, a yarn, or a tape as claimed in claim 21 , wherein the polypropylene/ethylene copolymer has an ethylene content of 9% to about 24% by weight of copolymer.
23. The monofilament, yarn, or tape of claim 21 , wherein each has a tenacity of at least 0.9 g/Denier at 1% strain, at least 1.75 g/Denier at 2% strain, and at least 4 g/Denier at 5% strain.
24. The monofilament, yarn, or tape of claim 21 , wherein each has a tenacity of about 1 g/Denier at 1% strain, about 1.95 g/Denier at 2% strain, and about 4.6 g/Denier at 5% strain.
25. A monofilament, a yarn, or a tape, each having a draw ratio of about 11.5 to about 25:1 and a tenacity of at least 0.75 g/Denier at 1% strain, at least 1.5 g/Denier at 2% strain, and at least 3.75 g/Denier at 5% strain, and comprising:
a melt blended admixture of about 93% by weight of polypropylene, about 5% by weight of a polypropylene/ethylene copolymer having an ethylene content of 8% to 25% by weight of copolymer, and about 2 wt. % of an additive;
wherein the monofilament, yarn, or tape respectively is a homogenous construction.
26. The monofilament, yarn, or tape of claim 25 , wherein each has a tenacity of at least 0.9 g/Denier at 1% strain, at least 1.75 g/Denier at 2% strain, and at least 4 g/Denier at 5% strain.
27. The monofilament, yarn, or tape of claim 25 , wherein each has a tenacity of about 1 g/Denier at 1% strain, about 1.95 g/Denier at 2% strain, and about 4.6 g/Denier at 5% strain.