Hoechst Aktiengesellschaft

Stefan Sinzig

Hajo Hagens

Wolfgang Oberhausen

Thomas Heusel

Reinhard Kober

An air-displacement roller bears against a film roll and extends to the ends of the film roll. A film web is fed to a winding core via a contact cylinder and is wound to form the film roll. The air layers carried along by the roll and the film web are included between the particular uppermost roll plies and for the most part are pressed out of the film roll via the end faces of the latter by the air-displacement roller. Each of the two roller ends is movable via a pressure mechanism articulated on a roller holder, the air-displacement roller being pressed against the film roll with a linear force lower than 10 N/cm to higher than 0.2 N/cm.

Method and apparatus for preventing air entrapment in a rolled web

In an interstice 6 between a film reel 8 and a contact roll 3, two air displacement rollers 5a, 5b are arranged parallel to the film reel 8 and the contact roll 3. In comparison with the contact roll and the winding core 2, these two air displacement rollers have a smaller diameter of about 7.5 to 50 mm. The rollers squeeze out the air boundary layers 4 at the film web layers 1 moving into the interstice 6. The contact roll 3 and one of the air displacement rollers 5a have a smooth hard surface layer with an average peak-to-valley height Ra of less than 0.4 microns and a Brinell hardness HB of greater than 10 HB 2.5/62.5. The distance between the two air displacement rollers and the contact point of film reel with the contact roll is chosen so small that new air boundary layers on the film web sections within the interstice can form only to a slight extent.

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Wiesbaden, Germany

Stefan Sinzig