Patent ID: 9221207
Filing Date: 2015-12-29
Classification: B29C,B29D,B29K,B29L,G02B

Abstract:
1. A method for producing a long stretched film, comprising at least a step of forming a long film made of thermoplastic resin, an oblique stretching step of delivering the long film in a specific direction different from a winding direction of a long stretched film after stretching and obliquely stretching the long film in a direction of an angle exceeding 0° and below 90° with respect to a width direction while gripping and conveying opposite end parts of the long film by a plurality of gripping tools of an oblique stretching device and a winding step of winding the long stretched film after the oblique stretching step, wherein: the oblique stretching device includes gripping tool travel support tools at opposite sides of the traveling long film; each of the gripping tool travel support tools at the opposite sides includes a plurality of gripping tools; the same number of the gripping tools are provided at the opposite sides; in the oblique stretching step, travel route lengths and traveling speeds at the opposite sides of the long stretched film per lap, from the grip start points when the long film is gripped by the plurality of gripping tools of the gripping tool travel support tools at an entrance of the oblique stretching device to the grip start points at the entrance of the oblique stretching device by way of grip release points where the long film is released at an exit of the oblique stretching device, are equal; the gripping tool traveling along the route of an inner gripping tool travel support tool reaches the grip release point and releases the long stretched film earlier than the gripping tool traveling along the route of an outer gripping tool travel support tool; an adjusting gear is provided in the inner gripping tool travel support tool to make the length of the route of the inner gripping tool travel support tool equal to that of the route of the outer gripping tool travel support tool; and a combination of the gripping tools forming a gripping tool pair is constantly the same at grip start points where the long film is gripped by the gripping tools.