Polyester film laminate with enhanced impact and tear resistance and method for its production

A method of forming a polymer film structure comprising:

• identifying a molecular orientation direction profile of two portions of biaxially oriented polymer film;
• layering said two portions such that said molecular orientation direction profile of one portion does not coincide with said molecular orientation direction profile of the other portion:
• wherein said portions of biaxially oriented film are formed by:
• forming a cast sheet;
• biaxially orienting said cast sheet and forming an optical bow therein;
• during such orienting step, increasing the extinction angle of said optical bow at an edge of said cast sheet relative to films formed by standard base film production.

A method of forming a polymer film structure comprising:

• identifying a molecular orientation direction profile of two portions of biaxially oriented polymer film;
• layering said two portions such that said molecular orientation direction profile of one portion does not coincide with said molecular orientation direction profile of the other portion:
• wherein said portions of biaxially oriented film are formed:
• forming a cast sheet;
• biaxially orienting said cast sheet and forming an optical bow therein;
• during said orienting step, rendering the extinction angle curve of said optical bow more negatively concave relative to films formed by standard base film production.