Opaque white film, useful for interior cladding, displays, signs and labels, comprises a crystallizable thermoplastic, barium sulfate and an optical brightening agent

摘要

An opaque white 10-500 mu m thick film (I) comprising a crystallizable thermoplastic contains at least barium sulfate and an optical brightening agent which are either processed into the thermoplastic at the raw material stage or are added as a master batch during film production. An independent claim is included for a process for the production of the film (I) by extrusion through a slit, stretching the amorphous film precursor onto a cooled roller, heating and stretching in the transverse and longitudinal directions with as optional second longitudinal stretch at a temperature of 10-60 K above Tg by 2-5 (2.5-4.5) times in the longitudinal and 2-5(3-4.5) times in the transverse direction with the second longitudinal stretch of 1.1-3 times.