Extensible nonwoven fabric

1. A nonwoven fabric comprising a plurality of fibers that are bonded together to form a coherent web, the fibers comprising a polymeric blend of a metallocene catalyzed polypropylene component, a polyethylene component, and a third polymer component that is at least partially miscible in the metallocene catalyzed polypropylene component and polyethylene component, wherein the nonwoven fabric exhibits a 20 to 30% increase in toughness in comparison to a similar nonwoven fabric comprising a Ziegler-Natta catalyzed polypropylene in place of the metallocene catalyzed polypropylene.

2. The fabric of claim 1 , wherein the third polymer component comprises a polypropylene copolymer or terpolymer.

3. The fabric of claim 1 , wherein the plurality of fibers are point bonded to each other with a bonding pattern having a cross-direction rod shape.

4. The fabric of claim 1 , wherein the bonds cover 8 to 15% of a surface are of the nonwoven fabric.

5. The fabric of claim 1 , wherein the nonwoven fabric has been subject to a solid state deformation such that the fibers have become permanently elongated.

6. The fabric of claim 1 , wherein the fibers are extensible and substantially inelastic.

7. The fabric of claim 1 , wherein the fibers are multicomponent fibers having a sheath/core arrangement in which the sheath comprises polyethylene and the core comprises said polymeric blend.

8. The fabric of claim 1 , wherein the fibers are monocomponent fibers.

9. The fabric of claim 1 , wherein the fabric comprises a spunbond fabric, and wherein the fabric exhibits one or more of

a) an increase in machine direction elongation at 5 N is that is from about 5 to 40% in comparison to the similar fabric having a Ziegler-Natta catalyzed polypropylene in place of the metallocene catalyzed polypropylene;

b) an increase in cross direction elongation at 5 N is that is from about 5 to 40% in comparison to the similar fabric having a Ziegler-Natta catalyzed polypropylene in place of the metallocene catalyzed polypropylene;

c) an increase in machine direction elongation at 10 N is that is from about 20 to 80% in comparison to the similar fabric having a Ziegler-Natta catalyzed polypropylene in place of the metallocene catalyzed polypropylene; or

d) an increase in cross direction elongation at 10 N is that is from about 20 to 80% in comparison to the similar fabric having a Ziegler-Natta catalyzed polypropylene in place of the metallocene catalyzed polypropylene.

10. The fabric of claim 1 , wherein the fabric comprises a spunbond fabric, and wherein the fabric exhibits an increase in machine direction elongation at 5 N is that is from about 10 to 30% in comparison to the similar fabric having a Ziegler-Natta catalyzed polypropylene in place of the metallocene catalyzed polypropylene.

11. The fabric of claim 1 , wherein the fabric comprises a spunbond fabric, and wherein the fabric exhibits an increase in cross direction elongation at 5 N is that is from about 10 to 30% in comparison to the similar fabric having a Ziegler-Natta catalyzed polypropylene in place of the metallocene catalyzed polypropylene.

12. The fabric of claim 1 , wherein the fabric comprises a spunbond fabric, and wherein the fabric exhibits an increase in machine direction elongation at 10 N is that is from about 25 to 70% in comparison to the similar fabric having a Ziegler-Natta catalyzed polypropylene in place of the metallocene catalyzed polypropylene.

13. The fabric of claim 1 , wherein the fabric comprises a spunbond fabric, and wherein the fabric exhibits an increase in cross direction elongation at 10 N is that is from about 25 to 70% in comparison to the similar fabric having a Ziegler-Natta catalyzed polypropylene in place of the metallocene catalyzed polypropylene.

14. The fabric of claim 1 , wherein the fabric comprises a spunbond fabric, and wherein the fabric exhibits

a) an increase in machine direction elongation at 5 N is that is from about 10 to 25% in comparison to the similar fabric having a Ziegler-Natta catalyzed polypropylene in place of the metallocene catalyzed polypropylene;

b) an increase in cross direction elongation at 5 N is that is from about 10 to 25% in comparison to the similar fabric having a Ziegler-Natta catalyzed polypropylene in place of the metallocene catalyzed polypropylene;

c) an increase in machine direction elongation at 10 N is that is from about 30 to 70% in comparison to the similar fabric having a Ziegler-Natta catalyzed polypropylene in place of the metallocene catalyzed polypropylene; and

d) an increase in cross direction elongation at 10 N is that is from about 30 to 70% in comparison to the similar fabric having a Ziegler-Natta catalyzed polypropylene in place of the metallocene catalyzed polypropylene.

15. The fabric of claim 1 , wherein the fabric comprises a spunbond fabric in which the fibers have been thermally bonded with a bond pattern having a cylindrical or rod shape, and wherein the fabric exhibits one or more of

a) an increase in machine direction elongation at 5 N is that is from about 20 to 250% in comparison to a similar fabric that has been thermally bonded with an oval shaped bond pattern;

b) an increase in cross direction elongation at 5 N is that is from about 40 to 300% in comparison to a similar fabric that has been thermally bonded with an oval shaped bond pattern;

c) an increase in machine direction elongation at 10 N is that is from about 30 to 225% in comparison to a similar fabric that has been thermally bonded with an oval shaped bond pattern; or

d) an increase in cross direction elongation at 10 N is that is from about 15 to 150% in comparison to a similar fabric that has been thermally bonded with an oval shaped bond pattern.

16. The fabric of claim 15 , wherein the bonds cover from 8 to 12% of the fabric.

17. The fabric of claim 1 , wherein the fabric comprises a spunbond fabric in which the fibers have been thermally bonded with a bond pattern having a cylindrical or rod shape, and wherein the fabric exhibits one or more of

a) an increase in machine direction elongation at 5 N is that is from about 25 to 150% in comparison to a similar fabric that has been thermally bonded with an oval shaped bond pattern;

b) an increase in cross direction elongation at 5 N is that is from about 75 to 100% in comparison to a similar fabric that has been thermally bonded with an oval shaped bond pattern;

c) an increase in machine direction elongation at 10 N is that is from about 75 to 125% in comparison to a similar fabric that has been thermally bonded with an oval shaped bond pattern; or

d) an increase in cross direction elongation at 10 N is that is from about 25 to 70% in comparison to a similar fabric that has been thermally bonded with an oval shaped bond pattern.

18. The fabric of claim 1 , wherein the fabric has an abrasion resistance from about 0.02 to 0.06 mg/cm 2 as measured by The Sutherland Ink Rub test method.

19. The fabric of claim 1 , wherein the fabric has a 20 to 30% increase in toughness in comparison to a similar nonwoven fabric comprising a Ziegler-Natta catalyzed polypropylene in place of the metallocene catalyzed polypropylene.

20. The fabric of claim 1 , wherein the fibers have a reverse bicomponent arrangement and in which the polymer blend is present in a sheath of the fiber, and a polymer having a lower melting temperature than said polymer blend defines a core of the fiber.

21. A composite sheet material having an SMS or SMMS construction in which the spunbond layer comprises the nonwoven fabric of claim 1 .

22. An absorbent article comprising the fabric of claim 1 .

23. The absorbent article of claim 22 , wherein the article comprises a diaper.

24. An extensible nonwoven fabric comprising the nonwoven of claim 1 having a root mean square peak tensile of about 10 N/5 cm or less and a root mean square peak elongation greater than 400% as measured in accordance with the High Speed Deformation Simulation at 800 mm/minute.

25. The fabric of claim 24 , wherein the fabric has a root mean square peak tensile of about 5 to 10 N/5 cm, and a root mean square peak elongation from about 400% to 600%.

26. The fabric of claim 24 , wherein the fabric has a root mean square peak tensile of about 6 to 9 N/5 cm, and a root mean square peak elongation from about 425 to 550% as measured in accordance with the High Speed Deformation Simulation at 800 mm/minute.

27. The fabric of claim 24 , wherein the fabric comprises a plurality of fibers having a bicomponent sheath core arrangement in which a first polymer component in the sheath has a higher melting temperature than a second polymer component in the core of the fiber.

28. The fabric of claim 27 , wherein the first polymer component comprises a polymeric blend of a metallocene catalyzed polypropylene component, a polyethylene component, and a third polymer component that is at least partially miscible in the metallocene catalyzed polypropylene component and the polyethylene component.