Patent ID: 8105456

Claim:
A method of making a breathable film laminate comprising: (a) providing a first thermoplastic polyurethane film; (b) applying to a first release substrate a layer of a film-formable liquid composition containing a volatile component; (c) heating the liquid composition on the first release substrate to expel the volatile component, thereby forming a first porous film having a multiplicity of micropores on the first release substrate; (d) transferring the first porous film to a first surface of the first thermoplastic polyurethane film from the first release substrate and pressing the first porous film against the first thermoplastic polyurethane film while the first porous film is hot, thereby bonding thermally the first porous film to the first thermoplastic polyurethane film; and (e) cooling the first porous film, wherein the method further comprises forming a second porous film on a second release substrate under heat; and transferring the second porous film to a second surface of the first thermoplastic polyurethane film from the second release substrate and pressing the second porous film against the first thermoplastic polyurethane film so that the second porous film is thermally bonded to the first thermoplastic polyurethane film.