GB344485A - Improvements in and apparatus for the manufacture and production of films and foils - Google Patents

Abstract

Foils or films are formed from substances such as polymerization products of hydrocarbons of the butadiene series or of vinyl compounds, synthetic resins prepared by condensation of aromatic dicarboxylic acids with polyhydric alcohols, gelatine, rubber, and the like, by causing the liquefied substance to flow on to two diverging conveyer belts running at the same speed, in the neighbourhood of the vertex of the angle formed by the two said belts. The film which is continuously produced in the gradually increasing area between the conveyer belts may subsequently be caused to pass over two belts which are parallel or nearly parallel to each other. In Figs. 1 and 2, the film-forming substance flows from the hopper V on to the pulley a which <PICT:0344485/IV/1> <PICT:0344485/IV/2> <PICT:0344485/IV/3> <PICT:0344485/IV/4> carries the two belts d. The formed film may be transferred to parallel belts e and again transferred if desired to another pair of diverging belts f, the purpose of the latter being to avoid the formation of irregularities in the film. The film on the parallel belts may be subjected to drying, hardening or vulcanizing. A pair of circular knives g are used to remove the film from the belts, the film being finally wound on a roller h. By way of example, a solution of polymerized butadiene in cyclohexane may be fed from the hopper V, and the film formed, while on the bands e, is treated with sulphur chloride. In Figs. 11 and 12 an apparatus is shown in which only one pair of belts is used to form and to carry the film during drying &c. The film-forming substance is caused to flow from a slot-shaped aperture p to the centre of the belts d, which are then caused to diverge by passing over two pairs of rollers l1 and l3, the two rollers of each pair being spaced slightly apart as shown in Fig. 12; the belts are parallel during the final run to the pulleys n. Other suitable forms of apparatus are shown in which only one pair of conveyer belts is used. In Figs. 7 and 8 (not shown) the conveyer belts are first caused to run parallel and close together, after which they diverge and then transfer the film which is produced on to another pair of parallel belts from which it is removed by passing on to a third pair running at a slightly higher rate, thereby subjecting the film to tension.