Breathable multilayer films with breakable skin layers

• Main Authors: A.L. MCCORMACK, W.B. HAFFNER
• Format: Patent
• Language: English
• Published: 11.12.2002
• Edition: 7
• Subjects: ACCESSORIES; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING; BANDAGES, DRESSINGS OR ABSORBENT PADS; CHEMISTRY; COMPOSITIONS BASED THEREON; COMPOSITIONS OF MACROMOLECULAR COMPOUNDS; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF,TUBULAR STRUCTURES OF THE BODY, E.G. STENTS; DIAGNOSIS; FILTERS IMPLANTABLE INTO BLOOD VESSELS; FIRST-AID KITS; FOMENTATION; HUMAN NECESSITIES; HYGIENE; IDENTIFICATION; INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULARARTICLES; INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS; 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; METALLURGY; ORGANIC MACROMOLECULAR COMPOUNDS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; OUTERWEAR; PERFORMING OPERATIONS; PROSTHESES; PROTECTIVE GARMENTS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDEDFOR; SHAPING OR JOINING OF PLASTICS; SURGERY; THEIR PREPARATION OR CHEMICAL WORKING-UP; TRANSPORTING; TREATMENT OR PROTECTION OF EYES OR EARS; WEARING APPAREL; WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE, IN GENERAL

A breathable multilayer film including a breathable core layer and one or two skin layers is prepared by providing a core layer mixture of a thermoplastic polymer and a particulate filler, providing a skin layer mixture of at least two incompatible polymers, coextruding the core and skin layer mixtures to form a multilayer film, and stretching the multilayer film to cause void formation in the core layer and crack formation in the one or two skin layers. By forming cracks in the skin layers during stretching, the skin layers can perform dual functions of alleviating die build-up of filler from the core layer during coextrusion, and bonding the film to a substrate subsequent to coextrusion, without unduly hindering the moisture vapor transmission rate of the film or laminate product. The breathable film, and laminates including the film, are useful in a wide variety of personal care absorbent articles, medical garments, and other products.