Latent elastic nonwoven composite

• Main Authors: SIQUEIRA JOSE, HUGHES JANIS WILSON, MACE TAMARA LEE, SANDERS CHRISTIAN
• Format: Patent
• Language: English
• Published: 08.09.2009
• Subjects: AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING; BANDAGES, DRESSINGS OR ABSORBENT PADS; CONVEYING; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF,TUBULAR STRUCTURES OF THE BODY, E.G. STENTS; FILTERS IMPLANTABLE INTO BLOOD VESSELS; FIRST-AID KITS; FOMENTATION; HANDLING THIN OR FILAMENTARY MATERIAL; HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS,CABLES; HUMAN NECESSITIES; HYGIENE; LAYERED PRODUCTS; LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT ORNON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM; MEDICAL OR VETERINARY SCIENCE; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; PACKING; PERFORMING OPERATIONS; PROSTHESES; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDEDFOR; SHAPING OR JOINING OF PLASTICS; STORING; TRANSPORTING; TREATMENT OR PROTECTION OF EYES OR EARS; WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE, IN GENERAL

A nonwoven composite that exhibits latent elastic properties is provided. More specifically, latent elasticity may be imparted by blending a thermoplastic elastomer with a polyolefin that is capable of forming semi-crystalline domains among the amorphous elastomeric chains, and then forming a film from the blend. The film is then stretched in one or more directions to orient the amorphous elastomer chains. Without intending to be limited by theory, the present inventors believe that the oriented state of the amorphous chains may be held in place by the relatively stiff semi-crystalline olefin domains. Subsequently, the stretched film may be activated (e.g., heated) to shrink the film and provide it with "latent" stretchability. For instance, the stretched film may be heated at or above the softening temperature of the polyolefin to soften the crystalline domains and allow the amorphous chains to return to their unoriented state. As a result of the present invention, the elastic film may be extended and recover from its unoriented state.