Composite elastomeric material and process for making the same

• US 4,720,415 A
• Filed: 07/30/1985
• Issued: 01/19/1988
• Est. Priority Date: 07/30/1985
• Status: Expired due to Term

• Current Assignee: Kimberly-Clark Worldwide Incorporated (Kimberly-Clark Corporation)
• Original Assignee: Kimberly-Clark Corporation
• Inventors: Vander Wielen, Michael J., Taylor, Jack D.
• Primary Examiner(s): Bell, James J.
• Application Number:
  US06/760,437
• Time in Patent Office: 903 Days
• Field of Search: 428/156, 428/170, 428/171, 428/172, 428/198, 428/296, 428/284, 428/286, 428/287, 428/340, 428/903, 428/152, 156/163, 156/164, 156/183, 156/290
• US Class Current: 428/152
• CPC Class Codes: A61F 13/15593 having elastic ribbons fixed thereto; Devices for applying the ribbons
• CPC Class Codes: A61F 13/4902 characterised by the elastic material
• CPC Class Codes: B29C 65/18 using heated tools
• CPC Class Codes: B29C 66/1122 Single lap to lap joints, i.e. overlap joints B29C66/45, B29C66/472, B29C66/52272 take precedence
• CPC Class Codes: B29C 66/234 said joint lines being in the form of tessellations
• CPC Class Codes: B29C 66/41 Joining substantially flat articles B29C66/47 and subgroups take precedence; Making flat seams in tubular or hollow articles B29C66/51 and subgroups take precedence
• CPC Class Codes: B29C 66/43 Joining a relatively small portion of the surface of said articles B29C66/45 takes precedence
• CPC Class Codes: B29C 66/71 characterised by the composition of the plastics material of the parts to be joined welding bar compositions B29C65/125
• CPC Class Codes: B29C 66/7294 Non woven mats, e.g. felt
• CPC Class Codes: B29C 66/81433 being toothed, i.e. comprising several teeth or pins comprising a single tooth B29C66/81429, or being patterned
• CPC Class Codes: B29C 66/83413 cooperating rollers, cylinders or drums
• CPC Class Codes: B29K 2021/003 Thermoplastic elastomers
• CPC Class Codes: B29K 2096/04 Block polymers
• CPC Class Codes: B29K 2995/0046 Elastic
• CPC Class Codes: B29L 2031/4878 Diapers, napkins
• CPC Class Codes: B32B 2262/0215 Thermoplastic elastomer fibers
• CPC Class Codes: B32B 2262/023 Aromatic vinyl resin, e.g. styrenic (co)polymers
• CPC Class Codes: B32B 2262/0253 Polyolefin fibres vinyl or acrylic copolymers B32B2262/0223 or B32B2262/0246
• CPC Class Codes: B32B 2307/51 Elastic
• CPC Class Codes: B32B 2555/02 Diapers or napkins
• CPC Class Codes: B32B 3/28 : characterised by a layer comprising a deformed thin sheet , i.e. the layer having its entire thickness deformed out of the plane, e.g. corrugated, crumpled B32B29/08 takes precedence
• CPC Class Codes: B32B 5/022 : Non-woven fabric
• CPC Class Codes: B32B 5/04 : characterised by a layer being specifically extensible by reason of its structure or arrangement , e.g. by reason of the chemical nature of the fibres or filaments
• CPC Class Codes: D04H 1/559 : the fibres being within layered webs
• CPC Class Codes: Y10S 428/903 : Microfiber, less than 100 micron diameter
• CPC Class Codes: Y10T 428/24446 : Wrinkled, creased, crinkled or creped
• CPC Class Codes: Y10T 428/24826 : Spot bonds connect components

Abstract

A method of producing a composite elastic material comprises stretching an elastic web to elongate it, for example, elongating a nonwoven web of meltblown elastomeric fibers, and bonding the elongated web to at least one gatherable web, such as a spunbonded polyester fiber material, under conditions which soften at least a portion of the elastic web to form the bonded composite web of elastic material. The composite material is relaxed immediately after the bonding to prevent the elastic web from losing its ability to contract from the stretched dimensions which it assumed during the bonding step. Such immediate relaxation of the composite material after the bonding step results in the elastic web retaining its ability to contract so that, upon termination of the elongating force, the elastic web contracts to form gathers in the gatherable web. The bonding may be effectuated by pattern embossing overlaid elastic and gatherable webs with at least portions of the elastic web heated to at least its softening temperature. The resultant composite elastic material comprises a coherent elastic web which is bonded to at least one coherent gatherable web whereby the gatherable web is extensible and contractible with the elastic web upon stretching and relaxing of the composite material.

Claims

1. A method of producing a composite elastic material comprising the steps of:

elongating a nonwoven fibrous elastic web having a basis weight of from about 5 to about 300 grams per square meter;

joining the elongated nonwoven fibrous elastic web at spaced-apart locations to at least one gatherable web;

relaxing the elongated nonwoven fibrous elastic web whereby the gatherable web is gathered between said spaced-apart locations.

2. The method of claim 1 wherein the nonwoven fibrous elastic web has a basis weight of from about 5 to about 200 grams per square meter.

3. The method of claim 1 wherein the nonwoven fibrous elastic web has a basis weight of from about 5 to about 100 grams per square meter.

4. The method of claim 1 wherein the nonwoven fibrous elastic web is joined to the gatherable web under conditions which soften said spaced-apart locations of said nonwoven fibrous elastic web and the nonwoven fibrous elastic web is relaxed immediately after the joining step.

5. The method of claim 1 wherein the nonwoven fibrous elastic web includes microfibers having a diameter not greater than about 100 microns.

6. The method of claim 1 wherein the nonwoven fibrous elastic web includes microfibers having a diameter of from about 1 to about 50 microns.

7. The method of claim 4 wherein the nonwoven fibrous elastic web is joined to the gatherable web at a temperature of from about 65°

C. to about 120°

C.

8. The method of claim 4 wherein the nonwoven fibrous elastic web is joined to the gatherable web at a temperature of from about 70°

C. to about 90°

C.

9. The method of claim 1 or claim 5 wherein the nonwoven fibrous elastic web is comprised of an A-B-A'"'"' block copolymer wherein A and A'"'"' are the same or different thermoplastic polymer block, and wherein B is an elastomeric polymer block.

10. The method of claim 9 wherein A and A'"'"' each is a thermoplastic styrenic moiety and B is selected from the group consisting of poly(ethylene-butylene), polyisoprene and polybutadiene.

11. The method of claim 10 wherein B is poly(ethylene-butylene).

12. The method of claim 10 wherein each of A and A'"'"' is selected from the group consisting of polystyrene and polystyrene homologs.

13. The method of claim 12 wherein B is poly(ethylene-butylene).

14. The method of claim 1 or claim 5 wherein the gatherable web comprises a nonwoven, non-elastic material.

15. The method of claim 10 wherein the sum of the molecular weight of A plus the molecular weight of A'"'"' comprises from about 14 to 31 percent of the molecular weight of the A-B-A'"'"' block copolymer.

16. The method of claim 11 wherein the sum of the molecular weight of A plus the molecular weight of A'"'"' comprises from about 14 to 29 percent of the molecular weight of the A-B-A'"'"' block copolymer.

17. The method of claim 13 wherein the nonwoven fibrous elastic web is comprised of a blend of said block copolymer plus a polyolefin.

18. The method of claim 17 wherein the polyolefin is selected from the group consisting of one or more of polyethylene, polypropylene, polybutene, ethylene copolymers, propylene copolymers and butene copolymers.

19. The method of claim 1 or claim 5 wherein the nonwoven fibrous elastic web is joined to the gatherable web by passing the elastic and gatherable webs in an overlaid configuration through a pressure nip formed between a pair of bonding rolls, at least one of said rolls comprising a patterned calender roller and at least one of said rolls being heated to a temperature above the softening temperature of the nonwoven fibrous elastic web.

20. The method of claim 1 or claim 5 including maintaining the nonwoven fibrous elastic web in a stretched condition at of at least about 100 percent elongation during the joining.

21. The method of claim 1 or claim 5 wherein the gatherable web comprises a non-elastic web.

22. The method of claim 5 including maintaining the nonwoven fibrous elastic web in a stretched condition of at least about 25 percent elongation during the joining.

23. The method of claim 5 including maintaining the nonwoven fibrous elastic web in a stretched condition of from about 25 percent to 550 percent during the joining.

24. The method of claim 22 wherein the nonwoven fibrous elastic web has a basis weight of from about 5 to about 200 grams per square meter.

25. The method of claim 22 wherein the gatherable web comprises a nonwoven, non-elastic web.

26. The method of claim 1 or claim 5 including bonding a non-elastic web to each of the opposite sides of the nonwoven fibrous elastic web.

27. The method of claim 1 or claim 5 wherein the nonwoven fibrous elastic web is relaxed for a period up to about 30 seconds after joining.

28. An elastic composite material comprising at least one nonwoven fibrous elastic web having a basis weight of from about 5 to about 300 grams per square meter joined at spaced-apart locations to at least one gatherable web, said gatherable web being gathered between said spaced-apart locations.

29. The material of claim 28 wherein the nonwoven fibrous elastic web has a basis weight of from about 5 to about 200 grams per square meter.

30. The material of claim 28 wherein the nonwoven fibrous elastic web has a basis weight of from about 5 to about 100 grams per square meter.

31. The material of claim 28 wherein the nonwoven fibrous elastic web includes microfibers having a diameter of not greater than about 100 microns.

32. The material of claim 28 wherein the nonwoven fibrous elastic web includes microfibers of from about 1 to about 50 microns in diameter.

33. The material of claim 28 wherein the nonwoven fibrous elastic web comprises a nonwoven web of meltblown elastomeric fibers selected from the group consisting of (i) fibers of A-B-A'"'"' block copolymers wherein A and A'"'"' may be the same or different thermoplastic polymer block and B is an elastomeric polymer block, and (ii) fibers of blends of one or more polyolefins with A-B-A'"'"' block copolymers wherein A and A'"'"' each is a styrenic moiety and B is poly(ethylene-butylene).

34. The material of claim 33 wherein each of A and A'"'"' is selected from the group consisting of polystyrene and polystyrene homologs, and the polyolefin is selected from the group consisting of one or more of polyethylene, polypropylene, polybutene, ethylene copolymers, propylene copolymers and butene copolymers.

35. The material of claim 33 wherein each of A and A'"'"' is selected from the group consisting of polystyrene and polystyrene homologs and the sum of the molecular weight of A plus the molecular weight of A'"'"' is from about 14 to 29 percent of the molecular weight of the A-B-A'"'"' block copolymer.

36. The material of claim 34 wherein the block copolymer comprises at least about 10% by weight of the fibers.

37. The material of claim 34 wherein the block copolymer comprises at least about 20% by weight of the fibers.

38. The material of claim 34 wherein the block copolymer comprises at least about 30% by weight of the fibers.

39. The material of claim 34 wherein the fibers are comprised of from about 10 percent to 90 percent by weight of the A-B-A'"'"' block copolymer and from about 90 percent to 10 by weight of the polyolefin.

40. The material of claim 28 or claim 31 wherein the nonwoven fibrous elastic web is joined to the gatherable web at a plurality of spaced-apart locations in a repeating pattern.

41. The material of claim 40 wherein the gatherable web is a nonwoven, non-elastic material.

42. The material of claim 41 wherein the gatherable web comprises a web of fibers selected from the group consisting of polyester fibers, polyolefin fibers, polyamide fibers, cellulosic fibers and mixtures of two or more thereof.

43. The material of claim 41 wherein the gatherable web comprises a nonwoven web of poly(ethylene terephthalate) fibers.

44. An elastic composite material comprising at least one nonwoven fibrous elastic web having a basis weight of from about 5 to about 300 grams per square meter, said nonwoven fibrous elastic web including microfibers having a diameter of not greater than about 100 microns and being joined, at spaced-apart locations, to at least one gatherable web, said gatherable web being gathered between said spaced-apart locations.