A coated polyester film with a coat on at least one side has been granted a patent. The coating solution contains a self-emulsifiable isocyanate with repeating units of ethylene oxide and two or more isocyanate groups. At least one polymer selected from the group consists of polyesters, polymers of vinyl monomers and polyurethanes. A polymer with a glass transition temperature of not lower than 0° C. dries and strentches the coated film.