PROCESS FOR PRODUCING A NON-TRANSPARENT MICROVOIDED SELF-SUPPORTING FILM

摘要

A process for producing a non-transparent microvoided self- supporting film comprising the steps of: i) mixing at least one linear polyester having together monomer units consisting essentially of terephthalate, isophthalate and aliphatic dimethylene with the molar ratio of isophthalate monomer units to terephthalate monomer units being at least 0.02 to provide a linear polyester matrix; at least one amorphous high polymer with a higher glass transition temperature than the glass transition temperature of said linear polyester matrix and/or at least one crystalline high polymer having a higher melting point than the glass transition temperature of said linear polyester matrix; and optionally at least one ingredient from the group of ingredients consisting of inorganic opacifying pigments, whitening agents, UV-absorbers, light stabilizers, antioxidants, flame retardants and colorants in a kneader or an extruder; ii) forming the mixture produced in step i) in a thick film followed by quenching; iii) longitudinally stretching the thick film at a stretching force of >4 N/mm² to at least twice the initial length; and iv) transversly stretching the longitudinally stretched film from step (iii) to at least twice the initial width; the use of the non-transparent microvoided axially stretched film produced according to the above-described process as a synthetic paper; and the use of the non-transparent microvoided axially stretched film produced according to the above-described process image recording elements.