Patent ID: 8377354

Claim:
A process for manufacturing a film consisting of one layer of a thermoplastic fluoropolymer and one layer of a polymer (A), in which blow extrusion process comprises the steps of 1) coextruding in order a multi-layer film consisting of: a) one layer of a thermoplastic fluoropolymer, wherein said fluoropolymer comprises a polyvinylidene fluoride homopolymer or copolymer containing at least 50% by weight of vinylidene fluoride; b) one layer of a polymer (A), wherein polymer (A) comprises an acrylic polymer having at least 50 mol % of (meth)acrylate; c) one layer of another thermoplastic polymer (B), wherein the thermoplastic polymer (B) being incompatible with the fluoropolymer and the polymer (A) and possesses an extrudate strength sufficient to support the layers of fluoropolymer and polymer (A), and wherein said layers of a), b) and c) are adjacent to each other in the order a), b), c), wherein polymer (A) has affinity for and adheres to the fluoropolymer, and wherein polymer (B) has no adhesion affinity with polymer (A); 2) cooling the coextrudate; and 3) recovering by separation from the layer of (B) the film consisting of the layers of a) and b), wherein the thickness of the layer of the film of incompatible polymer (B) is from 0.3 to 2 times the sum of the thickness of the fluoropolymer layer and of the layer of polymer (A).