PURPOSE: To form a polyurethane layer of high optical quality usable in the production of safety window by using a semicrystalline oriented polyester support film having a fluoropolymer-containing cover provided on the surface thereof so as to intend the reception of a liquid mass.

CONSTITUTION: A polyester used in order to obtain a support as a composite material film is a polyester generally used in order to obtain a biaxially stretched semicrystalline film. This polyester is crystallized by orientation and obtained from at least one aromatic dicarboxylic acid and at least one aliphatic glycol. The anti-adhesive layer on the surface of the support is obtained by bonding an aq. compsn. containing a fluoropolymer or a mixture of the fluoropolymer and a water dispersible polyester having a sulfonyloxy group on the surface of the support. This fluoropolymer is a polymer such as vinylidene fluoride or a copolymer of vinylidene fluoride or the like and a non-fluoride monomer.