GB813857A - Production of antificial filaments of uneven denier - Google Patents

Abstract

Artificial filamentary materials having a variation in denier along their length are produced by drawing the materials under tension to reduce their thickness and periodically varying the length of path of the materials, to vary the drawing ratio, by running them, while they are being drawn, over a guide surface which deflects them from a direct path in a plane containing said direct path, and moving the surface transversely to the plane. The guide surface may be the peripheral rim of a cam mounted for rotation in a plane transverse to the path of the filaments, the axis of rotation being substantially parallel to said path and the radius of the cam increasing gradually and uniformly and then decreasing abruptly so as to cause a corresponding abrupt decrease in the rate of drawdown. Alternatively the cam, e.g. in the form of a flat bar, may be mounted for rotation in a plane parallel to the path of the filaments, provision being made for periodically moving the cam as a whole transversely to the path so that the desired abrupt reduction in draw-down is caused by the filaments slipping off the side edge of the cam as the cam moves transversely. The guide surface need not have any rotary motion and may, for example, be a rod, mounted transversely to and below the path of the filaments, which may be moved upwards to engage and lift the filaments to lengthen the path of the filaments, then transversely to the path of the filaments until the filaments slip off the end of the rod, and then downwards under the filaments to start the cycle anew. Although the process is particularly applicable to the spinning of artificial filaments it may be used to produce filaments of uneven denier by stretching previously spun filaments, means being provided for bringing the filaments to a plastic condition. The process may also be used for the cold drawing of nylon filaments to give filaments of uneven denier.