HIGH-STRENGTH OPAQUE POLYESTER FILM

摘要

PURPOSE: A polyester film comprising a primary polyester resin consisting of ethyleneterephthalate and a secondary polyester resin consisting of ethylene-2,6-naphthalate is provided which can lower the incidence of orientation breakage in the film forming process and has high tensile strength and low light transmissivity. CONSTITUTION: A high-strength opaque polyester film comprises (a)60-80 mol% primary polyester resin having above 70 mol% ethyleneterephthalate repeating units and (b) 20-40 mol% secondary polyester resin having above 80 mol% ethylene-2,6-naphthalate repeating units, has a sum of a longitudinal and transverse tensile strength of above 32 kg/mm¬2 when an elongation ratio is 5% and a light transmissivity of below 5%. The film is substantially useful as use for a graphic art or a label and the like.