Calendering method and products made thereby

Claim 1

A PROCESS FOR CALENDERING HOLLOW TUBING COMPRISING, IN A PROCESS WHEREIN A MOLTEN BULK OF NONTHERMOSETTING THERMOPLASTIC MATERIAL IS DEPOSITED AT EACH OF AT LEAST TWO SEPARATE SUCCESSIVELY SPACED APART CONVERGING SURFACES ADJACENT TO A COMMON MOVING CARRIER SURFACE TO FORM SUCCESSIVE NIPS THEREWITH THROUGH WHICH A FILM EMERGES FROM EACH BULK OF THERMOPLASTIC MATERIAL, THE FILM EMERGING FROM THE FIRST OF SAID SUCCESSIVE NIPS RELEASABLY ADHERING TO THE MOVING CARRIER SURFCE AND THE FILMS EMERGING FROM SUBSEQUENT SUCCESSIVE NIPS EACH SUPERPOSING THE FILM EMERGING FROM THE PREVIOUS NIP, THE STEPS IN COMBINATION THEREWITH OF: (A) INTRODUCING AND PASSING A PREFORMED SEPARATORY RELEASABLE FOIL BETWEEN THE BULK OF THE THERMOPLASTIC MATERIAL AT AT LEAST ONE NIP AND THE FILM EMERGING FROM THE NIP IMMEDIATELY PRECEDING SAID ONE NIP BY APPLYING SAID SEPARATORY RELEASABLE FOIL ONTO EXPOSED THERMALLY SOFTENED TACKY SURFACE OF SAID FILM AT A POINT INTERMEDIATE THE PRECEDING NIP AND SAID ONE NIP PRIOR TO CONTACT WITH THE MOLTEN BULK OF THERMOPLASTIC MATERIAL AT SAID ONE NIP, SAID FOIL BEING CARRIED THEREON INTO AND THROUGH SAID ONE NIP, THE FOIL BEING NARROWER THAN THE SUPERPOSED FILMS EMERGING FROM SAID ONE NIP; (B) POSITIONING THE NARROW SEPARATORY RELEASABLE FOIL AS IT IS APPLIED ON SAID FILM SO THAT IT IS BETWEEN THE LONGITUDINAL EDGES OF THE SUPERPOSED FILMS EMERGING FROM SAID ONE NIP; (C) FUSING TO THE FILM FROM SAID PRECEDING NIP THE FILM FORMED FROM THE BULK OF THERMOPLASTIC MATERIAL AT SAID ONE NIP AS IT IS FORMED AT SAID ONE NIP ONLY IN THE AREAS ALONG THE LONGITUDINAL EDGES THEREOF BEYOND THE EDGES OF THE NARROW SEPARATORY FOIL; AND (D) STRIPPING THE TUBING IN COLLAPSED FORM FROM THE MOVING CARRIER SURFACE AFTER EMERGING FROM THE LAST OF SUCH SUCCESSIVE CONVERGING SURFACES.