Patent ID: 7503994

Claim:
A continuous process for the production of a composite film comprising at least one layer of a flexible polyvinylbutyral safety film together with at least one layer of flexible plastic carrier film, the method comprising: drawing said flexible safety film and said flexible carrier film from separate feed rollers, heating said flexible safety film to at least a bonding temperature, and passing the heated flexible safety film and the flexible carrier film through a pair of nip rollers, thereby pressing the heated flexible safety film and the flexible carrier film together to form the composite film, wherein the heated flexible safety film is not under tension when it is pressed together with the carrier film to form the composite film so as to avoid stretching of the flexible safety film and reduce wrinkling of the composite film during said production process, wherein during drawing of said flexible carrier film and pressing the heated flexible safety film and the flexible carrier film together to form the composite film, the flexible carrier film is maintained under tension.