Self-crimping multicomponent polymer fibers and corresponding methods of manufacture

• US 6,811,873 B2
• Filed: 06/03/2003
• Issued: 11/02/2004
• Est. Priority Date: 05/31/2000
• Status: Active Grant

• Current Assignee: Hills Limited (Hills Steadfast Investments Limited)
• Original Assignee: Hills Limited (Hills Steadfast Investments Limited)
• Inventors: Nadkarni, Vikas
• Primary Examiner(s): Edwards, N.
• Application Number:
  US10/276,310
• Publication Number:
  US 20040013877A1
• Time in Patent Office: 518 Days
• Field of Search: 428/370, 428/373, 428/374
• US Class Current: 428/370
• CPC Class Codes: D01D 5/253 with a non-circular cross section; Spinnerette packs therefor D01D5/38 takes precedence
• CPC Class Codes: D01D 5/30 Conjugate filaments; Spinnerette packs therefor
• CPC Class Codes: D01D 5/32 Side-by-side structure; Spinnerette packs therefor
• CPC Class Codes: D01D 5/34 Core-skin structure; Spinnerette packs therefor
• CPC Class Codes: D01F 8/14 with at least one polyester as constituent
• CPC Class Codes: D04H 1/435 Polyesters
• CPC Class Codes: D04H 1/43828 sheath-core
• CPC Class Codes: D04H 1/43832 side-by-side
• CPC Class Codes: D04H 1/43912 fibres with noncircular cross-sections
• CPC Class Codes: D04H 1/43918 nonlinear fibres, e.g. crimped or coiled fibres
• CPC Class Codes: D04H 3/00 Non-woven fabrics formed wholly or mainly of yarns or like filamentary material of substantial length
• CPC Class Codes: D04H 3/02 characterised by the method of forming fleeces or layers, e.g. reorientation of yarns or filaments
• 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 428/2924 Composite
• 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.]

Abstract

A self-crimping multicomponent fiber is manufactured utilizing the same-polymer components including at least one polymer component having a higher viscosity than at least one other polymer component. Crimping of the fiber is induced during fiber formation by achieving an effective crystallinity differential between the differing viscosity polymer components. The effective crystallinity differential may be obtained by varying a number of parameters during fiber formation, including the viscosity differential between polymer components and the transverse cross-sectional geometries of the differing viscosity components. Other factors, such as selecting a suitable drawing tension for the fiber can influence the crystallinity differential between differing viscosity components and thus resultant fiber crimp.

Claims

1. A method of forming a self-crimping multicomponent fiber comprising:

(a) passing a plurality of streams of polymer components through a spinneret hole, wherein the plurality of streams includes a first polymer component and a second polymer component, the first and second polymer components are same-polymer components and the first polymer component includes a higher viscosity than the second polymer component;

(b) extruding the plurality of streams from the spinneret hole, wherein the streams combine to form the multicomponent fiber;

(c) quenching the multicomponent fiber at a location downstream from the spinneret hole; and

(d) establishing an effective crystallinity differential between the first and second polymer components of the multicomponent fiber by at least the combination of selecting a suitable viscosity differential between the first and second polymer components and selecting a suitable perimeter-to-area ratio of transverse cross-sections of the first and second polymer components, wherein the transverse cross-section of the first polymer component differs from the transverse cross-section of the second polymer component.

2. The method of claim 1, wherein (d) includes:

(d1) selecting a perimeter-to-area ratio of the first polymer component that is greater than a perimeter-to-area ratio of the second polymer component.

3. The method of claim 2, wherein (b) includes:

(b1) extruding the first polymer component through a portion of the spinneret hole having an elongated geometry and the second polymer component through a portion of the spinneret hole having a geometry selected from the group consisting of substantially round and substantially square, wherein the first and second polymer components emerge from the spinneret hole adjacent each other with transverse cross-sectional geometries substantially similar to their respective spinneret hole portions.

4. The method of claim 3, wherein the plurality of streams further includes a third polymer component with a higher viscosity than the second polymer component, and (b1) includes:

(b11) extruding the third polymer component through a portion of the spinneret hole having an elongated geometry, wherein the third polymer component emerges from the spinneret hole adjacent the second polymer component with a transverse cross-sectional geometry substantially similar to its respective spinneret hole portion.

5. The method of claim 1, wherein (c) includes:

(c1) directing a stream of air toward the multicomponent fiber, wherein the first polymer component is upstream in the air stream in relation to the second polymer component.

6. The method of claim 1, wherein (d) includes:

(d1) establishing the effective crystallinity differential by varying at least another parameter selected from the group consisting of draw ratio, draw temperature and spinning speed; and

the method further comprises;

(e) drawing the quenched multicomponent fiber to induce crimping of the multicomponent fiber.

7. The method of claim 6, further comprising:

(f) heating the drawn multicomponent fiber to a selected temperature to induce further crimping of the multicomponent fiber.

8. The method of claim 6, wherein the first and second polymer components arc PET.

9. The method of claim 8, wherein (d) includes:

(d1) selecting a draw temperature in a range of between about 110°

C. and about 140°

C.

10. The method of claim 8, wherein (d) includes:

(d1) selecting a draw ratio between about 1.4 to about 1.7.

11. The method of claim 1, wherein (b) includes:

(b1) extruding the plurality of streams such that a portion of the transverse cross-section of the first polymer component is adjacent a portion of the transverse cross-section of the second polymer component.

12. The method of claim 1, wherein (b) includes:

(b1) extruding the plurality of streams such that a transverse cross-section of one of the first and second polymer components is surrounded by a transverse cross section of the other of the first and second polymer components.

13. The method of claim 12, wherein the transverse cross-section of the second polymer component is surrounded by the transverse cross-section of the first polymer component.

14. A method of forming a fabric comprising:

(a) combining a plurality of fibers, wherein at least one of the fibers is a multicomponent self-crimping fiber manufactured according the method of claim 1.

15. The method of claim 14, wherein (a) includes:

(a1) combining the plurality of fibers to form one of a woven fabric and a non-woven web.

16. A crimped, multicomponent fiber comprising a plurality of polymer components including a first polymer component and a second polymer component, wherein the first and second polymer components are same-polymer components, the first polymer component includes a higher viscosity than the second polymer component, each of the first and second polymer components includes a transverse cross-sectional geometry configured to achieve an effective crystallinity differential between the first and second polymer components during formation of the fiber, and the transverse cross-sectional geometry of the first polymer component differs from the transverse cross-sectional geometry of the second polymer component.

17. The fiber of claim 16, wherein the transverse cross-sectional geometry of the first polymer component includes a greater perimeter-to-area ratio than the transverse cross-sectional geometry of the second polymer component.

18. The fiber of claim 17, wherein the transverse cross-sectional geometry of the first polymer component is elongated and the transverse cross-sectional geometry of the sccond polymer component is selected from the group consisting of substantially round and substantially square.

19. The fiber of claim 18, wherein the plurality of same-polymer components further includes a third polymer component including a higher viscosity than the second polymer component and a transverse cross-sectional geometry that is elongated.

20. The fiber of claim 16, wherein a portion of the transverse cross-sectional geometry of the first polymer component is adjacent a portion of the transverse cross-sectional geometry of the second polymer component.

21. The fiber of claim 16, wherein the transverse cross-sectional geometry of one of the first and second polymer components is surrounded by the transverse cross-sectional geometry of the other of the first and second polymer components.

22. The fiber of claim 21, wherein the transverse cross-sectional geometry of the second polymer component is surrounded by the transverse cross-sectional geometry of the first polymer component.

23. The fiber of claim 16, wherein the first and second polymer components are PET. present invention is illustrated in FIG. 4. The transverse cross-section of the fiber of FIG. 4 is similar to the “

keyhole”

embodiment of FIG. 3 in that a “

hole”

portion 174 is occupied by polymer B and an “

arm”

portion 172 extending from the “

hole”

portion is occupied by polymer A. The geometric embodiment of FIG. 4 further includes a second “

arm”

portion 172 that extends from “

hole”

portion 174 approximately 180°

from “

arm”

portion 172 and is also occupied by polymer A. This configuration also yields an effective crystallinity differential during formation of the fiber that results in a stable crimp. The geometry of FIG. 4 further provides a resultant crimp that is tighter than the geometry of FIG. 3 due to a dual effect of the two higher IV “

arm”

portions helically winding around the lower IV “

hole”

portion. It is noted that the geometry of FIG. 4 could be further modified to include any number of “

arm”

portions extending from the “

hole”

portion at varying angles with respect to each other, wherein higher IV polymer components having the same or different viscosities occupy the “

arm”

portions, to yield a resultant self-crimping fiber having desirable crimping characteristics.