Preparation of mineral filled white polyolefin film for e.g. packaging, includes deformation or extension to form micro cracks in between mineral particles and polyolefin material

摘要

A mixture of polyolefin material (11) and mineral particles (12) is extruded and the solidified film (10) is subjected to mechanical deformation or extension to form micro-cracks which are concentrated mainly in the regions between the inorganic particles and polyolefin material. A method for preparing a white film comprising a mineral-filled polyolefin comprises mixing polyolefin granules with inorganic mineral particles, extruding the molten polymer material, allowing the material to solidify and subjecting the solidified film to a controlled mechanical deformation or extension in order to form local micro-cracks in the film. The deformation or extension step is carried out under conditions that ensure the micro-cracks are concentrated mainly in the regions between the inorganic particles and polyolefin material. An independent claim is also included for a mineral-filled film containing micro-cracks concentrated in the region between the inorganic particles and film base material.