POLYESTER OVER SHEET FOR CARD

摘要

PROBLEM TO BE SOLVED: To obtain a polyester over sheet for cards which prevents the surfaces of card and the like from being scratched by using a polyester film contg. particles (e.g. aluminum oxide particles) having a specified hardness. SOLUTION: Particles having a Mohs hardness of 7 or higher in an amount of 0.3-4wt.% is incorporated into a polyester film to give it a surface roughness of 0.01-0.06μm. A polyester film (e.g. a polyethylene terephthalate film) produced by extrusion and monoaxially stretched is pref. example of the particles is aluminum oxide particles, and the particle size is pref. 0.02-1μm though not specifically limited. The particles may be incorporated into the film by any known method, e.g. by adding or mixing the particles at an arbitrarily selected step of polyester production.