Extensible absorbent composites

• US 8,685,870 B2
• Filed: 02/20/2007
• Issued: 04/01/2014
• Est. Priority Date: 02/21/2006
• Status: Active Grant

• Current Assignee: Fitesa Nonwoven Inc
• Original Assignee: Fitesa Nonwoven Inc
• Inventors: Austin, Jared A., Baer, Samuel C.
• Primary Examiner(s): Chriss, Jennifer
• Assistant Examiner(s): Lopez, Ricardo E
• Application Number:
  US11/676,831
• Publication Number:
  US 20070197117A1
• Time in Patent Office: 2,597 Days
• Field of Search: 428/152, 428/182, 428/283, 428/284, 428/297, 281/04
• US Class Current: 442/389
• 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, inelastic meltblown fibers and a second layer of extensible, inelastic thermoplastic fibers, in which the meltblown fibers of the first layer and the extensible thermoplastic fibers of the second layer have been permanently elongated.

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 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 first layer formed of a coformed blend of absorbent fibers and extensible, inelastic meltblown fibers that have been permanently elongated by the application of tensile stress, and wherein the sheet material has been permanently elongated by 150% or greater of the sheet material'"'"'s original length.

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. An extensible composite sheet material comprising a first layer formed of a coformed blend of absorbent fibers and extensible, inelastic meltblown fibers that have been permanently elongated by the application of tensile stress, wherein the meltblown fibers of the first layer have been permanently elongated by 150% or greater of their original lengths.

24. An extensible composite sheet material comprising a first layer formed of a coformed blend of absorbent fibers and extensible, inelastic meltblown fibers and a second layer of extensible, inelastic thermoplastic fibers, wherein the first and second layers are joined to each other via thermally bonding such that the first and second layers define discrete layers in the composite sheet material, 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.

25. The extensible composite sheet material of claim 24, wherein the second layer comprises a spunbond nonwoven web.

26. The extensible composite sheet material of claim 24, wherein the first and second layers are point bond to each other.