Patent GB-1383589-A (GB)
Title: Stripping of thin films
IPC: B65H18/14
Filed: 1972-05-08
Abstract: 1383589 Thin films YARSLEY RESEARCH LABORATORIES Ltd 4 May 1973 [8 May 1972] 21368/72 Heading B5B Apparatus for stripping a continuous film 21 from a support web on which it has been formed comprises a pair of closely spaced stripping rolls 10, 11 disposed with their axes horizontal and which, in operation, are driven, on idler rolls 12, 13 positioned on either side of the pair of stripping rolls and spaced from and parallel to the adjacent stripping roll, a take-up roll 14, 15 resting on each stripping roll and its adjacent idler roll and supported only by them, and means 30, 31 for preventing axial movement of the take-up rolls while allowing rotational and radial movement thereof. The stripping rolls 10, 11 may be mounted so that the gap between them is adjustable, and is adjusted to a distance just greater than the combined thickness of the support web and the thin film. The ends of the spindles of the idler rolls 12, 13, as shown are mounted in horizontal slides 24 so that the separation between each idler roll and its adjacent stripping roll can be varied while maintaining the idler roll parallel to the stripping roll. Means may be provided for directly driving one of the stripping rolls and the other stripping roll may be coupled to the first through transmission means comprising gearing and a finely adjustable slipping clutch; Fig. 3, (not reproduced).  In operation, supply reel 16 carrying a supply of support web with adherent thin film and an interleaved paper web is positioned as shown and connected to the friction clutch. The paper web is manually wound on to the take-up roll 17 and the carrier web 21 is passed around rollers 18, 19, 20 as shown, through the gap between the stripping rolls 10 and 11, over roll 11, and wound on to the take-up roll 15 for a few turns. At 22 the film, which is uppermost, is cut, peeled back, passed over stripping roll 10 and wound for one or two turns on to the take-up roll 14. Drive to the stripping rolls 10, 11 is then started slowly and then increased to normal working speed. Stripping then takes place in the gap between rolls 10 and 11, the support web passing over roll 11 being taken up on roll 15 and the thin film passing over roll 10 to be taken up on to roll 15. Since take-up rolls 14, 15 are supported only by the rolls on which they rest, they can accommodate themselves to changes from true cylindricality as they are progressively built up, due to small variations in thickness across the width of the material being wound on. Idler roll 20 is so positioned that the support web with adherent thin film 21 makes contact with stripping roll 21 upstream of the gap between 10 and 11. This provides a greater length of contact between the support web and the driven roll 11, the driving force developed to pull the support web off the supply reel 16 and over the idler rolls 18, 19 and 20 being dependent on the frictional contact between the support web and the roll 11. When the size of the takeup rolls 14 and 15 becomes too large for the initial separation between the rolls 10 and 12, and 11 and 13, respectively, this separation may be increased by moving the roll 12 or 13 horizontally outwardly as required.