Latent elastic composite formed from a multi-layered film

Abstract

A nonwoven composite that exhibits latent elastic properties is provided. The composite is formed from a multi-layered, elastic film laminated to a nonwoven web facing. Latent elasticity is imparted to the composite through the use of at least one base layer that contains a thermoplastic elastomer and at least one skin layer that contains a propylene/α-olefin copolymer. During formation, the film is stretched in one or more directions to orient the elastomer chains. Without intending to be limited by theory, the present inventors believe that the oriented state of the chains may be held in place by the relatively stiff semi-crystalline domains of the propylene/α-olefin copolymer. The stretched elastic film may subsequently be relaxed and bonded to a nonwoven web facing to form the composite. The composite may be later activated (e.g., heated at or above the softening point of the copolymer) to soften the crystalline domains and allow the chains to return to their unoriented state. This causes the film to retract, which forms buckles in the nonwoven facing. In this manner, the resulting composite becomes elastic in that it has the ability to stretch and recover due to the 'latent' buckle formation in the nonwoven facing.