Stretchable composite sheets and processes for making

A process for preparing a stretchable multi-layer composite sheet comprising the steps of:

• providing a spirally-crimpable polymeric layer comprising at least 20 weight percent of spirally-crimpable multiple-component fibers, the multiple-component fibers having a cross-section and a length, and comprising a first polymeric component and a second polymeric component arranged in substantially distinct laterally eccentric zones across the cross-section of the multiple-component filaments and extending substantially continuously along the length of the multiple-component filaments;
• providing a non-spirally-crimpable polymeric layer comprising less than about 20 weight percent of laterally eccentric spirally-crimpable multiple-component fibers;
• intermittently bonding the first polymeric layer to the second polymeric layer with a plurality of bonds to form a bonded multi-layer composite sheet;
• heating the bonded multi-layer composite sheet to a temperature sufficient to cause the spirally-crimpable fibers in the first layer to develop three-dimensional spiral crimp, causing the bonded multi-layer composite sheet to shrink by at least 10% in area based on the original sheet area and the second polymeric layer to buckle between the bonds.

An article of fabric comprising a stretchable multi-layer composite sheet further comprising:

• a first polymeric layer comprising at least 20 weight percent of spirally-crimped multiple-component fibers, the multiple-component fibers having a cross-section and a length, and comprising a first polymeric component and a second polymeric component arranged in substantially distinct laterally eccentric zones across the cross-section of the multiple-component filaments and extending substantially continuously along the length of the multiple-component filaments;
• a second polymeric layer comprising less than 20 weight percent of laterally eccentric spirally-crimped multiple-component fibers and intermittently bonded to the first layer;
• the spirally-crimped multiple-component fibers in the first layer forming spirally-crimped fiber segments positioned substantially in the plane of the first layer and connecting the bonds;
• and
• the second layer forming buckled out-of-plane segments between the bonds.