Composite materials and process

• US 5,429,856 A
• Filed: 04/08/1994
• Issued: 07/04/1995
• Est. Priority Date: 03/30/1990
• Status: Expired due to Term

• Current Assignee: 3M Company
• Original Assignee: 3M Company
• Inventors: Wood, Leigh E., Krueger, Dennis L.
• Primary Examiner(s): Lesmes, George A.
• Assistant Examiner(s): Copenheaver, Blaine R.
• Application Number:
  US08/225,095
• Time in Patent Office: 452 Days
• Field of Search: 428/230, 428/231, 428/343, 428/373, 428/375, 428/376, 428/152, 428/179, 428/354, 604/385.6
• US Class Current: 604/370
• CPC Class Codes: A61F 13/51464 being stretchable or elastomeric
• CPC Class Codes: A61F 13/58 Adhesive tab fastener elements A61F13/5611, A61F13/5616, A61F13/66 take precedence
• CPC Class Codes: A61F 2013/49023 being textured, e.g. corrugated
• CPC Class Codes: A61F 2013/51427 having valves
• CPC Class Codes: B29C 2059/023 Microembossing
• CPC Class Codes: B29C 48/05 Filamentary, e.g. strands
• CPC Class Codes: B29C 48/08 flexible, e.g. films
• CPC Class Codes: B29C 48/19 the layers being joined at their edges
• CPC Class Codes: B29C 48/20 one of the layers being a strip, e.g. a partially embedded strip
• CPC Class Codes: B29C 48/21 the layers being joined at their surfaces
• CPC Class Codes: B29C 48/22 with means connecting the layers, e.g. tie layers or undercuts
• CPC Class Codes: B29C 48/307 specially adapted for bringing together components, e.g. melts within the die
• CPC Class Codes: B29C 55/023 using multilayered plates or sheets
• CPC Class Codes: B29C 59/18 by liberation of internal stresses, e.g. plastic memory
• CPC Class Codes: B29C 61/02 Thermal shrinking
• CPC Class Codes: B32B 2307/51 Elastic
• CPC Class Codes: B32B 25/08 of synthetic resin
• CPC Class Codes: B32B 27/12 next to a fibrous or filamentary layer
• CPC Class Codes: B32B 43/00 Operations specially adapted for layered products and not otherwise provided for, e.g. repairing; Apparatus therefor
• CPC Class Codes: Y10S 428/906 Roll or coil
• CPC Class Codes: Y10T 428/24446 : Wrinkled, creased, crinkled or creped
• CPC Class Codes: Y10T 428/24669 : Aligned or parallel nonplanarities
• CPC Class Codes: Y10T 428/249923 : Including interlaminar mechanical fastener
• CPC Class Codes: Y10T 428/28 : Web or sheet containing structurally defined element or component and having an adhesive outermost layer
• CPC Class Codes: Y10T 428/2848 : Three or more layers
• 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 428/2933 : Coated or with bond, impregnation or core
• CPC Class Codes: Y10T 428/2935 : Discontinuous or tubular or cellular core
• CPC Class Codes: Y10T 442/601 : Nonwoven fabric has an elastic quality

Abstract

Inelastic films comprising at least one elastomeric core and a surrounding inelastic matrix preferably prepared by coextrusion. The film when stretched and allowed to recover will create an elastomeric composite.

Claims

1. A coextruded film comprising at least two discrete laterally spaced and longitudinally parallel elastomeric cores capable of elastic elongation and an inelastic matrix thermoplastic polymeric material completely circumscribing said at least two discrete elastomeric cores so that there is a film region between said at least two elastomeric cores comprising inelastic matrix material, wherein the thickness and the presence of the core material varies across the film and wherein when said coextruded film is stretched past the inelastic deformation limit of the matrix material around said at least two cores the film will be capable of recovery in the cores to form an activated microtextured elastomeric material having microtextured skin layers formed of the matrix material over the at least two elastomeric cores.

2. The film of claim 1 wherein the laminate in said preferential activation zone will recover from its stretched length by 15% or more after at least 1 second.

3. The film of claim 1 wherein the laminate will recovery from its stretched length by 15% after at least 5 seconds.

4. The film of claim 1 wherein the film will recover from its stretched length by 15% after at least 20 seconds.

5. The film of claim 1 wherein the film will recover from its stretched length by less than 15% after 20 seconds and when then exposed to an activation temperature above 26.7°

C. will recover by at least 50% of the total recovery.

6. The film of claim 1 wherein the at least two elastomeric cores comprises an extrudable polymer and said matrix material is a thermoplastic polymer.

7. The film of claim 1 wherein the at least two cores are at approximately the same relative location to the two film faces.

8. The film of claim 1 wherein the at least two elastomeric cores are at different locations in said film relative to the two film faces.

9. The film of claim 1 comprised of at least two elastomeric cores in a thermoplastic matrix wherein at least two layers are at different locations in said film relative to the two film faces.

10. The film of claim 8 wherein the at least two elastomeric cores overlap.

11. The film of claim 1 comprising a diaper closure tab formed of the coextruded film having at least one end region free of elastomeric core containing regions coated with an adhesive layer.

12. The film of claim 11 further comprising a low adhesion backsize on at least one face thereof.

22. The elastomeric film of claim 12 further comprising a layer of pressure-sensitive adhesive on at least one outer face of said elastomeric film.

13. A coextruded elastomeric film comprising at least two discrete laterally spaced and longitudinally parallel elastomeric cores within a thermoplastic matrix, the thermoplastic matrix forming continuous skin layers over said elastomeric cores on two faces of the film with the thermoplastic matrix completely circumscribing said at least two elastomeric cores so that there is a film region between said at least two elastomeric cores comprising thermoplastic matrix material substantially free of elastomeric core material, wherein the thickness of the cores, and the core materials presence, varies across the film and said thermoplastic matrix has been stretched passed its inelastic deformation limit in at least one direction so as to form microtextured skin layers of the matrix material over the at least two elastomeric cores.

14. The elastomeric film of claim 13 comprising at least two elastomeric cores having deformed matrix material there between such that the deformed matrix material is formed into a uniform and periodic macroscopic folded structure between adjacent core-containing regions, the macroscopic folding comprising folding of the entire film in the region between adjacent core-containing regions without said macroscopic folded structure in said adjacent core-containing regions.

15. The elastomeric film of claim 13 comprising a diaper closure tab formed of the coextruded film having at least one end region free of elastomeric core coated with an adhesive layer.

16. The elastomeric film of claim 15 further comprising a low adhesion backsize on at least one face thereof.

17. The elastomeric film of claim 13 further comprising a garment wherein said elastomeric film provides discrete elastic regions.

18. The elastomeric film of claim 13 comprising a diaper backsheet wherein said elastomeric core comprises a discrete elasticized zone and said matrix material forms a liquid-impermeable diaper backsheet portion.

19. The elastomeric film of claim 18 wherein said discrete elasticized zone is a waistband engaging portion of said backsheet.

20. The elastomeric film of claim 18 wherein said discrete elasticized zone is a leg engaging portion of said backsheet.

21. The elastomeric film of claim 13 further comprising a layer of pressure-sensitive adhesive on at least one outer face of said elastomeric film.