BONDING UNSINTERED NON-EXPANDED PTFE FILM TO PTFE COATED SUBSTRATE

摘要

A method of bonding an unsintered unexpanded PTFE feed film (21)to a flexible PTFE coated substrate (32) , comprises providing a three roll calender (24) in which a metal surfaced roll (26) coacts with two filled rolls (28, 30) to define first and second nips (N1, N2) ; calendering the PTFE feed film in the first nip, with the thus calendered PTFE film remaining supported on the metal surfaced roll for transport to and through the second nip; and directing the PTFE coated substrate through the second nip for calendering with and bonding to the calendered PTFE film to thereby produce a laminated composite (33) .