BIAXIAL-ORIENTED CARRIER FILM OBTAINED THROUGH CO-EXTRUSION OF MULTILAYER FOR MAGNETIC INFORMATION CARRIER AND MANUFACTURE THEREOF

摘要

An abrasion-resistant, multilayer biaxially oriented carrier film for magnetic information media produced by coextrusion is described, said film being composed of a base layer (A) comprising a thermoplastic polymer matrix of essentially linear aromatic polyester, containing finely distributed solid particles to improve its surface roughness which determines the slip properties of the film, and of at least one cover layer (B) applied to one of the two surfaces of base layer (A). The characterizing features of the carrier film described consist in the fact that base layer (A) contains the solid particles in an an amount from 0.001 wt. % to 10 wt. %, based on the weight of the polymer forming base layer (A), whereby the average particle size of the solid particles lies in the range from 0.001 to 20 microns, by the fact that cover layer (B) comprises a thermoplastic polymer matrix of essentially linear aromatic copolyester, in which finely distributed solid particles are embedded in a quantity between 0 and 10 wt. %, based on the weight of the polymer forming cover layer (B), whereby the solid particles have an average particle diameter of less than 0.3 micron, and by the fact that the layer thickness of cover layer (B) is a maximum of 40% of the layer thickness of base layer (A).