BREATHABLE FILM FORMED FROM A RENEWABLE POLYESTER

• Main Authors: EBY, Tom, TOPOLKARAEV, Vasily, A, SCHOLL, Neil, T, MCENEANY, Ryan, J
• Format: Patent
• Language: English; French; German
• Published: 11.07.2018
• Subjects: AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F,C08G; CHEMISTRY; COMPOSITIONS BASED THEREON; COMPOSITIONS OF MACROMOLECULAR COMPOUNDS; GENERAL PROCESSES OF COMPOUNDING; METALLURGY; ORGANIC MACROMOLECULAR COMPOUNDS; PERFORMING OPERATIONS; PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCESIN A PLASTIC STATE; THEIR PREPARATION OR CHEMICAL WORKING-UP; TRANSPORTING; USE OF INORGANIC OR NON-MACROMOLECULAR ORGANIC SUBSTANCES ASCOMPOUNDING INGREDIENTS; WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE, IN GENERAL; WORKING-UP

A breathable film formed from a thermoplastic composition that contains a rigid renewable polyester and has a voided structure is provided. To achieve such a structure, a thermoplastic composition that contains a renewable polyester and polymeric toughening additive is extruded onto a surface to form a precursor film in which the toughening additive can be dispersed as discrete physical domains within a continuous matrix of the renewable polyester. The precursor film is thereafter stretched or drawn at a temperature below the glass transition temperature of the polyester (i.e., "cold drawn"). Without intending to be limited by theory, the present inventors believe that the deformation force and elongational strain of the drawing process causes debonding to occur in the renewable polyester matrix at those areas located adjacent to the discrete domains. This creates a network of voids located adjacent to the discrete domains.