Process and apparatus for the continuous production of flexible webs

摘要

Apparatus for the continuous production of films comprises a plurality of cylindrical elements of equal diameter, means for assembling the elements end-to-end to form a cylindrical mandrel, means for moving the mandrel along its axis and for rotating it about its axis, means for spraying a layer of film-forming material on to the surface of the mandrel at the rear end, means for cutting this layer near the forward end of the mandrel, in order to detach it, and means for periodically detaching the front element from the mandrel and attaching an element to the rear end. As shown, the mandrel M is supported in tubular guides 1, 2 by rollers 3, which may also serve to drive it. The guides 1, 2 may be fixed or rotatably mounted in bearings 8, 9, 10. A device 13 sprays layers of film-forming material on to the mandrel. The mandrel then passes through an apertured plate 22 carrying rollers 23 pressed against the surface of the covered mandrel. The covering is cut by knives 24 secured to guide 1, which knives may be heated to weld the cut edges. The film is taken up on bobbins on spindles 29, after passing over rollers 96, or may be used immediately without previous winding. When the mandrel section M1 is disengaged from the guide 1, it is separated from the mandrel by means not shown and carried by a cradle 42 mounted on chains or cables 45, 46 to the rear of the mandrel, when the shaft 37, is disconnected and the section is attached to the rear end of the mandrel. The Specification describes in detail alternative arrangements for joining the mandrel sections together, removing the sections from one end and adding them to the other, and for maintaining the movement of the mandrel. The mandrel elements may be heated or cooled internally by circulating a heating or cooling fluid, or heated by internal electric resistors, or external heating by fluid, radiation or convection may be employed. The apparatus may be used to produce films of different nature or colour wound in overlapping fashion, so that the final product consists of different juxtaposed zones oblique in relation to the edges of the film.