GB688463A - An improved process for winding film on to reels - Google Patents

Abstract

A process for winding a film, extruded with thickened margins, on to a cylindrical reel rotated by frictional contact of the film on the reel with a driving roll, is characterized in that the margins of the film are trimmed before winding to such an extent that the resultant edges of the film are not more than 75 per cent thicker than the centre of the film. The driving roll then contacts the roll being wound only at its edges, whereby the number of creases and other deformities included in the roll of film is reduced. The process is especially applicable to thin wide films, especially films produced from rubber and synthetic linear polymers. According to the Provisional Specification, the desired contact between the film and driving roll may be achieved by extruding the film through an orifice having dimensions such that the edges of the film are of the necessary increased thickness, or the winding reel may have built-up ends. Alternatively, the film may be passed through calender rolls which suitably reduce the thickness of the margins, or film of uniform thickness may be wound up with separate marginal strips of the required thickness.