Elastomeric bicomponent fibers comprising block copolymers having high flow

• US 20070004830A1
• Filed: 09/01/2006
• Published: 01/04/2007
• Est. Priority Date: 03/03/2004
• Status: Active Grant

• Current Assignee: Kraton Polymers US LLC (DL Holdings Co., Ltd.)
• Original Assignee: Kraton Polymers US LLC (DL Holdings Co., Ltd.)
• Inventors: Handlin, Dale, Flood, John, Ehrlich, Martin
• Granted Patent: US 8,003,209 B2
• Time in Patent Office: Days
• US Class Current: 524/69
• CPC Class Codes: C08F 297/04 polymerising vinyl aromatic monomers and conjugated dienes
• CPC Class Codes: C08F 297/044 using a coupling agent
• CPC Class Codes: C08L 2666/02 Organic macromolecular compounds, natural resins, waxes or and bituminous materials
• CPC Class Codes: C08L 2666/04 Macromolecular compounds according to groups C08L7/00 - C08L49/00, or C08L55/00 - C08L57/00; Derivatives thereof
• CPC Class Codes: C08L 51/006 grafted on to block copolymers containing at least one sequence of polymer obtained by reactions only involving carbon-to-carbon unsaturated bonds
• CPC Class Codes: C08L 53/00 Compositions of block copolymers containing at least one sequence of a polymer obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers
• CPC Class Codes: C08L 53/025 modified
• CPC Class Codes: D01F 8/06 with at least one polyolefin as constituent
• CPC Class Codes: D01F 8/10 with at least one other macromolecular compound obtained by reactions only involving carbon-to-carbon unsaturated bonds as constituent
• CPC Class Codes: D04H 1/4291 Olefin series
• CPC Class Codes: D04H 1/4334 Polyamides
• CPC Class Codes: D04H 1/435 Polyesters
• CPC Class Codes: D04H 3/16 with bonds between thermoplastic filaments produced in association with filament formation, e.g. immediately following extrusion
• CPC Class Codes: Y10T 428/2913 Rod, strand, filament or fiber
• CPC Class Codes: Y10T 428/2929 Bicomponent, conjugate, composite or collateral fibers or filaments [i.e., coextruded sheath-core or side-by-side type]
• CPC Class Codes: Y10T 428/2931 Fibers or filaments nonconcentric [e.g., side-by-side or eccentric, etc.]
• CPC Class Codes: Y10T 428/2967 Synthetic resin or polymer

Abstract

Bicomponent fibers comprising a thermoplastic polymer and an elastomeric compound are made which can be continuously extruded from the melt at high production rates. The elastomeric compound has high flow and consists essentially of a selectively hydrogenated block copolymer and a tackifier resin, an alpha-olefin copolymer, an alpha-olefin terpolymer, a wax or mixtures thereof. In one embodiment the block copolymer has at least one polystyrene block of molecular weight from 5,000 to 7,000 and at least one polydiene block of molecular weight from 20,000 to 70,000 and having a vinyl content of greater than 60 mol %. In a second embodiment the block copolymer has a vinyl content of less than 60 mol %. The bicomponent fibers are useful for the manufacture of articles such as woven fabrics, spun bond non-woven fabrics or filters, staple fibers, yarns and bonded, carded webs.

Claims

1. A bicomponent fiber comprising a thermoplastic polymer and an elastomeric compound wherein the elastomeric compound consists essentially of a selectively hydrogenated block copolymer having an S block and an E or E₁ block and having the general formula:

S-E-S, (S-E₁)_n, (S-E₁)_nS, (S-E₁)_nX

or mixtures thereof, wherein;

a. prior to hydrogenation the S block is a polystyrene block;

b. prior to hydrogenation the E block is a polydiene block, selected from the group consisting of polybutadiene, polyisoprene and mixtures thereof, having a molecular weight from 40,000 to 70,000;

c. prior to hydrogenation the E₁ block is a polydiene block, selected from the group consisting of polybutadiene, polyisoprene, and mixtures thereof, having a molecular weight from 20,000 to 35,000;

d. n has a value of 2 to 6 and X is the residue of a coupling agent;

e. the styrene content of the block copolymer is from 13 to 25 weight percent;

f. the vinyl content of the polydiene block prior to hydrogenation is from 70 to 85 mol percent;

g. the block copolymer includes less than 15 weight percent of units having the general formula;

S-E or S-E₁

wherein S, E and E₁ are as already defined;

h. subsequent to hydrogenation about 0 to 10% of the styrene double bonds have been hydrogenated and at least 80% of the conjugated diene double bonds have been hydrogenated;

i. the molecular weight of each of the S blocks is from 5,000 to 7,000 and a tackifying resin.

2. The bicomponent fiber of claim 1 wherein the melt index of the block copolymer is greater than or equal to 9 grams/10 minutes according to ASTM D1238 at 230°

C. and 2.16 kg weight.

3. The bicomponent fiber of claim 1 wherein the tackifying resin is from 5 to 30 wt % basis the elastomeric compound mass.

4. The bicomponent fiber of claim 1 wherein the polystyrene content of the block copolymer is from 15 to 24 weight percent.

5. The bicomponent fiber of claim 1 wherein the polydiene blocks E and E₁ have a vinyl content from 73 to 83 mol percent.

6. The bicomponent fiber of claim 1 wherein the molecular weight of the polystyrene block S is from 5,800 to 6,600.

7. The bicomponent fiber of claim 1 wherein the E block is polybutadiene having a molecular weight from 45,000 to 60,000, or the E₁ block is two or more coupled polybutadiene blocks, each of the polybutadiene blocks, prior to being coupled, has a molecular weight from 22,500 to 30,000.

8. The bicomponent fiber of claim 1 wherein the structure of the selectively hydrogenated block copolymer is (S-E₁)_nX and the block copolymer contains less than 10% of an uncoupled S-E₁ species.

9. The bicomponent fiber of claim 7 wherein the coupling agent is selected from the group consisting of tetramethoxy silane, tetraethoxy silane, tetrabutoxy silane, tetrakis(2-ethylhexyloxy) silane, methyl trimethoxy silane, methyl triethoxy silane, isobutyl trimethoxy silane, phenyl trimethoxy silane, silicon tetrachloride, methyl-trichlorosilane and dimethyl-dichlorosilane.

10. The bicomponent fiber of claim 1 wherein the melt flow rate of the block copolymer is at least 15 g/10 min at 230°

C. and 2.16 kg weight according to ASTM D1238.

11. The bicomponent fiber of claim 1 wherein the melt flow rate of the block copolymer is at least 40 g/10 min at 230°

C. and 2.16 kg weight according to ASTM D1238.

12. The bicomponent fiber of claim 1 wherein the thermoplastic polymer is selected from the group consisting of polypropylene, polyethylene, polyamides, poly(ethylene terephthalate), poly(butylene terephthalate), and poly(trimethylene terephthalate).

13. The bicomponent fiber of claim 12 wherein the thermoplastic-polymer is polypropylene having a melt flow of at least 20 g/10 min at 230°

C. and 2.16 kg according to ASTM D1238.

14. The bicomponent fiber of claim 12 wherein the thermoplastic polymer is linear low density polyethylene having a melt flow of at least 25 g/10 min at 190°

C. and 2.16 kg according to ASTM D1238.

15. The bicomponent fiber of claim 1 having a sheath-core morphology wherein the core consists of the elastomeric compound and the sheath consists primarily of the thermoplastic polymer.

16. The bicomponent fiber of claim 15 wherein the volume ratio of thermoplastic polymer sheath to elastomeric compound core is from 1/99 to 50/50.

17. The bicomponent fiber of claim 1 having an islands-in-the-sea morphology wherein the islands consist primarily of the elastomeric compound and the sea consists primarily of the thermoplastic polymer.

18. The bicomponent fiber of claim 17 wherein the volume ratio of thermoplastic polymer sea to elastomeric compound islands is from 1/99 to 50/50.

19. The bicomponent fiber of claim 1 having a denier from 0.5 to 20.

20. An article comprising the bicomponent fiber of claim 1 which is an elastic mono-filament, a woven fabric, a spun bond non-woven fabric, a melt-blown non-woven fabric or filter, a staple fiber, a yarn or a bonded, carded web.

21. A bicomponent fiber comprising a thermoplastic polymer and an elastomeric compound wherein the elastomeric compound consists essentially of a selectively hydrogenated block copolymer having an S block and an E or E₁ block and having the general formula:

S-E-S, (S-E₁)_n, (S-E₁)_nS, (S-E₁)_nX

or mixtures thereof, wherein;

a. prior to hydrogenation the S block is a polystyrene block;

b. prior to hydrogenation the E block is a polydiene block, selected from the group consisting of polybutadiene, polyisoprene and mixtures thereof, having a molecular weight from 40,000 to 70,000;

c. prior to hydrogenation the E₁ block is a polydiene block, selected from the group consisting of polybutadiene, polyisoprene, and mixtures thereof, having a molecular weight from 20,000 to 35,000;

d. n has a value of 2 to 6 and X is the residue of a coupling agent;

e. the styrene content of the block copolymer is from 13 to 25 weight percent;

f. the vinyl content of the polydiene block prior to hydrogenation is from 35 to 50 mol percent;

g. the block copolymer includes less than 15 weight percent of units having the general formula;

S-E or S-E₁

wherein S, E and E₁ are as already defined;

h. subsequent to hydrogenation about 0 to 10% of the styrene double bonds have been hydrogenated and at least 80% of the conjugated diene double bonds have been hydrogenated;

i. the molecular weight of each of the S blocks is from 5,000 to 7,000 and any one of a tackifying resin, an alpha-olefin copolymer, an alpha-olefin terpolymer, a wax or mixtures thereof.

22. The bicomponent fiber of claim 21 wherein the melt index of the elastomeric compound is greater than or equal to 15 grams/10 minutes according to ASTM D1238 at 230°

C. and 2.16 kg weight.

23. The bicomponent fiber of claim 21 wherein the melt index of the elastomeric compound is at least 40 grams/10 minutes according to ASTM D1238 at 230°

C. and 2.16 kg weight.

24. The bicomponent fiber of claim 21 wherein the alpha-olefin copolymer is selected from the group consisting of ethylene/alpha-olefin copolymers and propylene/alpha-olefin copolymers.

25. The bicomponent fiber of claim 21 wherein the alpha-olefin terpolymer is selected from the group consisting of ethylene/propylene/alpha-olefin terpolymers, ethylene/styrene/alpha-olefin terpolymers and propylene/styrene/alpha-olefin terpolymers.

26. The bicomponent fiber of claim 21 wherein the tackifying resin, alpha-olefin copolymer or alpha-olefin terpolymer is from 5 to 30 wt % basis the elastomeric compound mass.

27. The bicomponent fiber of claim 21 having a sheath-core morphology wherein the core consists of the elastomeric compound and the sheath consists primarily of the thermoplastic polymer.

28. The bicomponent fiber of claim 27 wherein the volume ratio of thermoplastic polymer sheath to elastomeric compound core is from 1/99 to 50/50.

29. The bicomponent fiber of claim 21 having an islands-in-the-sea morphology wherein the islands consist primarily of the elastomeric compound and the sea consists primarily of the thermoplastic polymer.

30. The bicomponent fiber of claim 29 wherein the volume ratio of thermoplastic polymer sea to elastomeric compound islands is from 1/99 to 50/50.

31. The bicomponent fiber of claim 21 having a denier from 0.5 to 20.

32. An article comprising the bicomponent fiber of claim 21 which is an elastic mono-filament, a woven fabric, a spun bond non-woven fabric, a melt-blown non-woven fabric or filter, a staple fiber, a yarn or a bonded, carded web.

33. A bicomponent fiber comprising a thermoplastic polymer and an elastomeric compound wherein the elastomeric compound consists essentially of a selectively hydrogenated block copolymer having an S block and an E or E₁ block and having the general formula:

S-E-S, (S-E₁)., (S-E₁)_nS, (S-E₁)_nX

or mixtures thereof, wherein;

a. prior to hydrogenation the S block is a polystyrene block;

b. prior to hydrogenation the E block is a polydiene block, selected from the group consisting of polybutadiene, polyisoprene and mixtures thereof, having a molecular weight from 40,000 to 70,000;

c. prior to hydrogenation the E₁ block is a polydiene block, selected from the group consisting of polybutadiene, polyisoprene, and mixtures thereof, having a molecular weight from 20,000 to 35,000;

d. n has a value of 2 to 6 and X is the residue of a coupling agent;

e. the styrene content of the block copolymer is from 13 to 25 weight percent;

f. the vinyl content of the polydiene block prior to hydrogenation is from 70 to 85 mol percent;

g. the block copolymer includes less than 15 weight percent of units having the general formula;

S-E or S-E₁

wherein S, E and E₁ are as already defined;

h. subsequent to hydrogenation about 0 to 10% of the styrene double bonds have been hydrogenated and at least 80% of the conjugated diene double bonds have been hydrogenated;

i. the molecular weight of each of the S blocks is from 5,000 to 7,000 and any one of an alpha-olefin copolymer, an alpha-olefin terpolymer, a wax or mixtures thereof.

34. The bicomponent fiber of claim 33 wherein the melt index of the block copolymer is greater than or equal to 9 grams/10 minutes according to ASTM D1238 at 230°

C. and 2.16 kg weight.

35. The bicomponent fiber of claim 33 wherein the alpha-olefin copolymer is selected from the group consisting of ethylene/alpha-olefin copolymers and propylene/alpha-olefin copolymers.

36. The bicomponent fiber of claim 33 wherein the alpha-olefin terpolymer is selected from the group consisting of ethylene/propylene/alpha-olefin terpolymers, ethylene/styrene/alpha-olefin terpolymers and propylene/styrene/alpha-olefin terpolymers.

37. The bicomponent fiber of claim 33 wherein the alpha-olefin copolymer or alpha-olefin terpolymer is from 5 to 49 wt % basis the elastomeric compound mass.

38. The bicomponent fiber of claim 33 having a sheath-core morphology wherein the core consists of the elastomeric compound and the sheath consists primarily of the thermoplastic polymer.

39. The bicomponent fiber of claim 33 wherein the volume ratio of thermoplastic polymer sheath to elastomeric compound core is from 1/99 to 50/50.

40. The bicomponent fiber of claim 33 having an islands-in-the-sea morphology wherein the islands consist primarily of the elastomeric compound and the sea consists primarily of the thermoplastic polymer.

41. The bicomponent fiber of claim 40 wherein the volume ratio of thermoplastic polymer sea to elastomeric compound islands is from 1/99 to 50/50.

42. The bicomponent fiber of claim 33 having a denier from 0.5 to 20.

43. An article comprising the bicomponent fiber of claim 33 which is an elastic mono-filament, a woven fabric, a spun bond non-woven fabric, a melt-blown non-woven fabric or filter, a staple fiber, a yarn or a bonded, carded web.