Extensible absorbent composites
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.
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.