MULTI LAYER POLYVINYL ACETAL FILM WHICH HAS AN EXCELLENT SOUND INSULATION PERFORMANCE IN VARIOUS EXTERNAL ENVIRONMENTS AND MANUFACTURING METHOD THEREOF

摘要

PURPOSE: A multi layer polyvinyl acetal film and a manufacturing method thereof are provided to maintain excellent puncture prevention performance and impact resistance even in hot and humid environment, thereby showing excellent performance by being used as a bonding film for glasses for a vehicle and a building.;CONSTITUTION: A multi layer polyvinyl acetal film has a structure in which a first resin layer and a second resin layer are alternately laminated. The first resin layer and the second resin layer respectively include a polyvinyl acetal resin, polymethylmethacrylate, and a resin which is selected by blending the polyvinyl acetal resin and the polymethylmethacrylate. At least one resin layer between the first resin layer and the second resin layer includes the polyvinyl acetal resin. A difference of a refractive index between the first and the second resin layer is 0.08 or less.;COPYRIGHT KIPO 2013