EXTENSIBLE ABSORBENT COMPOSITES

• US 20070197117A1
• Filed: 02/20/2007
• Published: 08/23/2007
• Est. Priority Date: 02/21/2006
• Status: Active Grant

• Current Assignee: Fitesa Nonwoven Inc
• Original Assignee: Fiberweb Simpsonville Incorporated (Évora SA)
• Inventors: Baer, Samuel, Austin, Jared
• Granted Patent: US 8,685,870 B2
• Time in Patent Office: Days
• US Class Current: 442/416
• CPC Class Codes: B32B 2250/20 All layers being fibrous or filamentary
• CPC Class Codes: B32B 2262/0253 Polyolefin fibres vinyl or acrylic copolymers B32B2262/0223 or B32B2262/0246
• CPC Class Codes: B32B 2262/062 Cellulose fibres, e.g. cotton
• CPC Class Codes: B32B 2262/067 Wood fibres
• CPC Class Codes: B32B 2262/12 Conjugate fibres, e.g. core/sheath or side-by-side
• CPC Class Codes: B32B 2262/14 Mixture of at least two fibres made of different materials
• CPC Class Codes: B32B 2307/726 Permeability to liquids, absorption
• CPC Class Codes: B32B 2307/728 Hydrophilic
• 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: B32B 5/08 the fibres or filaments of a layer being of different substances , e.g. conjugate fibres, mixture of different fibres
• CPC Class Codes: B32B 5/26 another layer next to it also being fibrous or filamentary relative arrangement of fibres or filaments of different layers B32B5/12
• CPC Class Codes: D04H 1/425 Cellulose series
• CPC Class Codes: D04H 1/4374 using different kinds of webs, e.g. by layering webs
• CPC Class Codes: D04H 1/559 the fibres being within layered webs
• CPC Class Codes: D04H 1/56 in association with fibre formation, e.g. immediately following extrusion of staple fibres
• CPC Class Codes: Y10T 442/659 Including an additional nonwoven fabric
• CPC Class Codes: Y10T 442/668 Separate nonwoven fabric layers comprise chemically different strand or fiber material
• CPC Class Codes: Y10T 442/681 Spun-bonded nonwoven fabric
• CPC Class Codes: Y10T 442/696 : Including strand or fiber material which is stated to have specific attributes [e.g., heat or fire resistance, chemical or solvent resistance, high absorption for aqueous compositions, water solubility, heat shrinkability, etc.]
• CPC Class Codes: Y10T 442/697 : Containing at least two chemically different strand or fiber materials
• CPC Class Codes: Y10T 442/698 : Containing polymeric and natural strand or fiber materials

Abstract

Absorbent sheet materials are produced from a coformed blend of absorbent fibers and extensible meltblown polymer fibers. Laminates of these extensible coforms are prepared with layers of extensible polymeric fibers or filaments. The absorbent sheet materials are incrementally stretched to improve softness and drape.

Claims

1. An extensible composite sheet material comprising a first layer formed of a coformed blend of absorbent fibers and extensible meltblown fibers and a second layer of extensible thermoplastic fibers.

2. The extensible composite sheet material of claim 1, wherein the second layer of extensible thermoplastic fibers comprises a nonwoven web.

3. The extensible composite sheet material of claim 2, wherein the nonwoven web is a spunbond web comprised of continuous filaments.

4. The extensible composite sheet material of claim 2, wherein the nonwoven web is a carded web of staple fibers.

5. The extensible composite sheet material of claim 2, wherein the nonwoven web is a meltblown web of meltblown fibers.

6. The composite sheet material of claim 1, wherein the meltblown fibers of the first layer are comprised of polyethylene.

7. The composite sheet material of claim 1, wherein the meltblown fibers of the first layer are comprised of blends of polypropylene homopolymer and polypropylene copolymer.

8. The extensible composite sheet material of claim 1, wherein the extensible thermoplastic fibers of the second layer are prepared from a propylene polymer or copolymer.

9. The extensible composite sheet material of claim 1, wherein extensible thermoplastic fibers of the second layer comprise polyethylene continuous filaments.

10. The extensible composite sheet material of claim 1, wherein the extensible thermoplastic fibers of the second layer (14) comprise a blend of at least two polymers which are immiscible with one another and at least one additional polymer which is miscible or partially miscible with said immiscible polymers.

11. The extensible composite sheet material of claim 10, wherein said blend of immiscible polymers comprises a propylene polymer and polyethylene.

12. The extensible composite sheet material of claim 1, wherein the extensible thermoplastic fibers of the second layer comprise multicomponent filaments.

13. The extensible composite sheet material of claim 1, wherein the extensible thermoplastic fibers of the second layer comprise sheath-core bicomponent filaments including a polyethylene sheath component and a polypropylene core component.

14. The extensible composite sheet material of claim 1, wherein functional particulate have been incorporated into the blend of absorbent fibers and meltblown fibers.

15. The extensible composite sheet material of claim 1, in which an additional layer of continuous extensible filaments is in intimate surface-to-surface contact with an opposite side of said coform layer and bonded thereto so that the additional layer of continuous extensible filaments defines an opposite exterior surface of the composite sheet material.

16. The extensible composite sheet material of claim 1, in which an additional layer formed of a coformed blend of absorbent fibers and extensible meltblown fibers is in intimate surface-to-surface contact with an opposite side of said layer of extensible thermoplastic fibers so that the additional layer defines an opposite exterior surface of the composite sheet material.

17. The extensible composite sheet material of claim 1, in which the meltblown fibers of the first layer and the extensible thermoplastic fibers of the second layer have been permanently elongated by the application of tensile stress.

18. The extensible composite sheet material of claim 17, which has been stretched by ring-rolling to permanently elongate the fibers and filaments.

19. The extensible composite sheet material of claim 17, which has been stretched by deep embossing to permanently elongate the fibers and filaments.

20. An extensible composite sheet material comprising a coformed blend of absorbent fibers and extensible meltblown fibers that have been permanently elongated by the application of tensile stress.

21. The extensible composite sheet material of claim 20 which has been stretched by ring-rolling to permanently elongate the extensible meltblown fibers.

22. The extensible composite sheet material of claim 20 which has been stretched by deep embossing to permanently elongate the extensible meltblown fibers.

23. A method of producing an extensible composite sheet material comprising forming an extensible coform layer containing absorbent fibers and extensible meltblown fibers, applying to one surface of the coform layer a layer of extensible thermoplastic fibers, and bonding the coform layer in intimate surface-to-surface contact to the layer of extensible thermoplastic fibers so that the coform layer defines an absorbent exterior surface of the composite sheet material.

24. The method of claim 23, comprising the further step of forming an additional extensible coform layer containing absorbent fibers and extensible meltblown fibers and bonding the additional coform layer in intimate surface-to-surface contact with an opposite side of said layer of extensible thermoplastic fibers so that the additional coform layer defines an opposite exterior surface of the composite sheet material.

25. The method of claim 23, comprising the further step of forming an additional layer of extensible thermoplastic fibers and bonding the additional layer in intimate surface-to-surface contact with an opposite side of said coform layer so that the additional layer defines an opposite exterior surface of the composite sheet material.

26. The method of claim 23, wherein the step of applying to one surface of the coform layer a layer of extensible thermoplastic fibers comprises forming a nonwoven web of said extensible thermoplastic fibers and applying the nonwoven web to said one surface of the coform layer.

27. The method of claim 23 including the further step of incrementally stretching the composite sheet material to deform and permanently elongate the fibers.

28. The method of claim 27 wherein the incremental stretching comprises ring-rolling.

29. The method of claim 27 wherein the incremental stretching comprises deep embossing.

30. The method of claim 23, wherein the step of forming an extensible coform layer comprises moving a collection surface past a first coform station and directing fiberized absorbent fibers into the path of freshly extruded extensible polymeric thermoplastic fibers exiting a meltblowing die and depositing the absorbent fibers and extensible thermoplastic fibers onto the moving collection surface to form said coform layer, and wherein the step of applying to one surface of the coform layer a nonwoven layer of extensible fibers comprises directing the thus-formed coform layer past a spunbond station and depositing a layer of freshly extruded continuous extensible filaments onto the coform layer.

31. The method of claim 30 comprising the further step of directing the moving collection surface with the first coform layer and the layer of continuous extensible filaments from the spunbond station and past a second coform station and forming a second coform layer on the layer of continuous extensible filaments by directing fiberized absorbent fibers into the path of freshly extruded extensible polymeric thermoplastic fibers exiting a meltblowing die, and wherein said bonding step comprises bonding the first and second coform layers and the layer of continuous extensible filaments together to form a composite sheet material.

32. The method of claim 23, including the step of moving a collection surface past a first spunbond station and depositing a web of freshly extruded continuous extensible filaments onto the collection surface, and wherein the step of applying to one surface of the coform layer a nonwoven layer of extensible fibers comprises directing the moving collection surface with the web of continuous extensible filaments thereon underneath a coform station and directing fiberized absorbent fibers into the path of freshly extruded extensible polymeric thermoplastic fibers exiting a meltblowing die and depositing the absorbent fibers and extensible thermoplastic fibers onto the web of continuous extensible filaments moving on the collection surface to form said coform layer.

33. The method of claim 32, including the further step of directing the moving collection surface with the web of continuous filaments and the thus-formed coform layer thereon under a second spunbond station and depositing a second web of continuous extensible filaments onto the coform layer.

34. The method of claim 30, including the further step of incrementally stretching the composite sheet material to deform and permanently elongate the fibers.

35. The method of claim 34 wherein the incremental stretching comprises ring-rolling.

36. The method of claim 34 wherein the incremental stretching comprises deep embossing.