ANCHORING LOOPS OF FIBERS NEEDLED INTO A CARRIER SHEET

• US 20080305297A1
• Filed: 06/05/2008
• Published: 12/11/2008
• Est. Priority Date: 06/07/2007
• Status: Active Grant

• Current Assignee: Velcro IP Holdings LLC
• Original Assignee: Velcro Industries BV (Chartwell Industries Ltd)
• Inventors: Provost, George A., Barker, James R.
• Granted Patent: US 8,673,097 B2
• Time in Patent Office: Days
• US Class Current: 428/89
• CPC Class Codes: A44B 18/0011 Female or loop elements A44B18/0007 takes precedence
• CPC Class Codes: D04H 1/485 in combination with weld-bonding
• CPC Class Codes: D04H 1/498 entanglement of layered webs
• CPC Class Codes: D04H 11/08 formed by creation of a pile on at least one surface of a non-woven fabric without addition of pile-forming material, e.g. by needling, by differential shrinking needling machines D04H18/00
• CPC Class Codes: Y10T 428/23936 Differential pile length or surface
• CPC Class Codes: Y10T 428/23957 Particular shape or structure of pile
• CPC Class Codes: Y10T 428/23986 With coating, impregnation, or bond

Abstract

Methods of forming a loop product are provided. Methods include needling polymeric fibers through a substrate to form hook-engageablc loop structures of the fibers extending from one surface of the substrate and then using heat and pressure to soften and bond polymer of the fibers directly to the substrate and adjacent fibers, thereby anchoring the loop structures to resist fiber pullout under fastening loads. Loop products are also provided.

Claims

1. A method of making a sheet-form loop product, the method comprising

placing a layer of staple fibers against a first side of a substrate;

needling fibers of the layer through the substrate by penetrating the substrate with needles that drag portions of the fibers through the substrate during needling, leaving exposed loops of the fibers extending from a second side of the substrate; and

anchoring fibers forming the loops by fusing the fibers to each other on the first side of the substrate, while substantially preventing fusion of the fibers on the second side of the substrate.

2. The method of claim 1 further comprising, prior to fusing, heating the fibers from the first side of the substrate.

3. The method of claim 1 further comprising cooling a surface that contacts the second side during the anchoring step.

4. The method of claim 1 wherein the fibers include bicomponent fibers having a core of one material and a sheath of another material, and wherein anchoring the fibers comprises melting material of the sheaths of the bicomponent fibers to bind fibers together.

5. The method of claim 1 wherein the fibers include first fibers having a relatively high melting temperature and second fibers having a relatively lower melting temperature, the melting temperature of the second fibers being selected to allow the second fibers to fuse and anchor the loops.

6. The method of claim 1 wherein anchoring the fibers to the substrate comprises laminating the fibers to the substrate by a laminating process comprising passing the needled substrate through a nip defined between a compliant rubber roll and a hot can.

7. The method of claim 6 further comprising cooling the surface of the compliant rubber roll.

8. The method of claim 7 wherein cooling comprises directing air onto the surface.

9. The method of claim 6 wherein the fibers are loose and unconnected to the substrate and each other until needled.

10. The method of claim 1 wherein, after anchoring, the fibers and filaments on the first side are fused together by a network of discrete bond points.

11. The method of claim 10 wherein the bond points are in a random distribution.

12. The method of claim 10 wherein the fibers comprise drawn staple fibers, and the fused fibers maintain a longitudinal molecular orientation throughout the bond points.

13. The method of claim 1 wherein needling fibers of the layer through the substrate and anchoring fibers forming the loops forms loops sized and constructed to be releasably engageable by a field of hooks for hook-and-loop fastening.

14. The method of claim 1 wherein the substrate comprises a nonwoven web.

15. The method of claim 14 wherein the nonwoven web comprises a spunbond web.

16. The method of claim 15 wherein, prior to needling, the spunbond web comprises a non-random pattern of fused, spaced apart regions, each fused region surrounded by unfused regions.

17. The method of claim 14 wherein the nonwoven web comprises filaments formed of a polymer selected from the group consisting of polyesters, polyamides, polyolefins, and blends and copolymer thereof.

18. The method of claim 14 wherein the nonwoven web comprises filaments having a specific gravity of less than about 1.5 g/cm³.

19. The method of claim 14 wherein the nonwoven web has a linear filament layer density of at least about 25 filaments/layer.

20. The method of claim 19 wherein the nonwoven web has an overall basis weight of less than about 0.75 osy.

21. The method of claim 1 wherein the staple fibers are disposed on the substrate in a layer of a total fiber weight of less than about 2 ounces per square yard (67 grams per square meter).

22. The method of claim 15 wherein the staple fibers are disposed on the substrate in a layer of a total fiber weight of no more than about one ounce per square yard (34 grams per square meter).

23. The method of claim 1 wherein the staple fibers are disposed on the substrate in a carded, unbonded state.

24. The method of claim 1 further comprising, prior to disposing the fibers on the substrate, carding and cross-lapping the fibers.

25. The method of claim 15 wherein the staple fibers and filaments of the nonwoven web are of substantially the same denier.

26. The method of claim 6 wherein pressure in the nip is from about 5 to about 40 psi.

27. The method of claim 6 further comprising selecting roll compliance, nip pressure and line speed so that nip dwell time is from about 25 to 200 msec.

28. The method of claim 6 further comprising preheating the substrate from the first side prior to the nip.

29. The method of claim 28 wherein preheating comprises training the substrate about a heated roll surface that carries the web into the nip.

30. The method of claim 29 further comprising applying tension to the substrate to maintain a contact pressure against the heated roll surface prior to the nip.

31. The method of claim 28 wherein preheating comprises heating the substrate, using infrared heating, to a temperature sufficient to soften but not melt surfaces of at least some of the fibers on the first side.

32. The method of claim 1 wherein the loop product has an overall weight of less than about 5 ounces per square yard (167 grams per square meter).

33. The method of claim 1 wherein the substrate comprises a polymer film.

34. The method of claim 1 wherein the substrate comprises a scrim.

35. The method of claim 1 wherein the substrate comprises paper.

36. The method of claim 1 wherein the needling step comprises elliptical needling.

37. The method of claim 1 further comprising embossing the loop product after anchoring the loop structures.

38. A sheet-form loop product comprising:

a substrate; and

a layer of staple fibers disposed on a first side of the substrate, exposed loops of the fibers extending from a second side of the substrate, with bases of the loops being anchored on the first side of the substrate;

wherein the fibers on the first side of the substrate are fused together to a relatively greater extent than the fibers on the second side of the substrate.

39. The loop product of claim 38 wherein the fibers on the first side are fused directly to one another.

40. The loop product of claim 38 wherein the fibers are substantially unbonded on the second side of the web.

41. The loop product of claim 38 wherein the second side of the web includes embossed areas, and the fibers are bonded only in the embossed areas.

42. The loop product of claim 38 wherein the fibers include bicomponent fibers having a core of one material and a sheath of another material, the fibers fused by melted material of the sheaths of the bicomponent fibers.

43. The loop product of claim 38 wherein the fibers include first fibers having a relatively high melting temperature and second fibers having a relatively lower melting temperature, the melting temperature of the second fibers being selected to allow the second fibers to fuse and anchor the loops.

44. The loop product of claim 42 wherein the bicomponent fibers make up between about 5 and 40 percent of the fibers, by weight.

45. The loop product of claim 43 wherein the second fibers make up between about 5 and 40 percent of the fibers, by weight.

46. The loop product of claim 38 wherein the staple fibers have a total fiber weight of less than about 2 ounces per square yard (67 grams per square meter).

47. The loop product of claim 46 wherein the staple fibers have a total fiber weight of no more than about one ounce per square yard (34 grams per square meter).

48. The loop product of claim 38 wherein the loop product has an overall weight of less than about 5 ounces per square yard (167 grams per square meter).

49. The loop product of claim 38 wherein the loops are hook-engageable and the product comprises a loop fastener product.