Fabric including polyolefin elastic fiber

1. A method for preparing a fabric including an elastomeric propylene-based polymer yarn wherein said yarn has an elongation of 200-800%, a tenacity of about 0.5 to about 1.5 grams/denier, a load power at 200% elongation of about 0.05 to about 0.35 grams/denier; and an unload power at 200% elongation of about 0.007 to about 0.035 grams/denier, said method comprising

(a) providing an elastomeric propylene-based copolymer composition comprising propylene and at least one monomer selected from a C 4 -C 20 α-olefin, a combination of ethylene and at least one C 4 -C 20 α-olefin and one or more dienes;

(b) heating said elastomeric propylene-based polymer composition in a single extruder to a temperature of about 220° C. to about 300° C.;

(c) maintaining said elastomeric propylene-based polymer composition at a temperature of about 135° C. to about 275° C. while extruding said composition through a capillary to form the yarn;

(d) winding said yarn onto a package at a winding speed of about 450 m/min to about 650 m/min;

(e) preparing a fabric including said yarn by knitting or weaving under tension at a draft of greater than 200%, and

(f) crosslinking said yarn.

2. The method of claim 1 , wherein the crosslinking is effected by exposing the yarn to an ebeam.

3. The method of claim 2 , wherein said yarn is exposed to the ebeam prior to winding on said package.

4. The method of claim 2 , wherein said package is exposed to an ebeam as a single package or a plurality of packages in a container.

5. A method for preparing an apparel fabric including an elastomeric propylene-based polymer yarn wherein said yarn has an elongation of 200-800%, a tenacity of about 0.5 to about 1.5 grams/denier, a load power at 200% elongation of about 0.05 to about 0.35 grams/denier; and an unload power at 200% elongation of about 0.007 to about 0.035 grams/denier, said method comprising:

(a) providing an elastomeric propylene-based providing an elastomeric propylene-based copolymer composition comprising propylene and at least one monomer selected from a C 4 -C 20 α-olefin, a combination of ethylene and at least one C 4 -C 20 α-olefin and one or more dienes;

(b) heating said elastomeric propylene-based polymer composition in a single extruder to a temperature of about 220° C. to about 300° C.;

(c) maintaining said elastomeric propylene-based polymer composition at a temperature of about 135° C. to about 275° C. while extruding said composition through a capillary to form the yarn;

(d) winding said yarn onto a package at a winding speed of about 450 m/min to about 650 m/min;

(e) preparing a warp comprising a plurality of said yarns;

(f) exposing said yarns to an ebeam to crosslink said yarns;

(g) taking up the yarn on a beam; and

(h) warp knitting an apparel fabric under tension at a draft of greater than 200%.