| 摘要 |
PURPOSE:To enhance the uniformity of a stretched film by a method wherein a course similar to the forming curved surface, which is made under the state that respective parts of the film are stretched uniformly, is taken by the film by supplying the predetermined liquid to the surface of the film under stretching. CONSTITUTION:Both the edges of a film 1 are pinched at points (a) and a' between pulleys 2 and 2', which are adjacent to each other, supported horizontally and rotated in the directions indicated with the arrows C and C', and belts 3 and 3', each of which is pressed against the lower semicircular part of the pulley and runs at the speed same as the peripheral speed of the pulley. The film 1 proceeds while being laterally stretched, turns round at points (b), releases at points (c) and c' from the pulleys and the belts and finally proceeds in the form of a stretched film. Liquid is supplied to a sack-like portion made by the proceeding film and the lower halves of the pulleys 2 and 2' so that the difference is made between the liquid level in the sack-like portion and that outside the sack-like portion so as to apply the internal pressure due to the static pressure of the liquid in the interior of the sack-like portion in order to hold the shape of the film ranging between the points (c) and c' in an approximate f-curved surface. |
