Improvements in or relating to the production of artificial filaments, straw, ribbons, or the like

摘要

For the production of artificial horsehair, bristles, tapes, straws, ribbons, and the like, a number of filaments, while in a condition to adhere to one another, are passed through a die with which the whole surface of the bundle of threads makes contact so that the product has a cross-section similar to that of the die. In a modification the filaments pass through a three-sided die, Figs. 6 and 7, whereby a flattened product is produced, the cross-section of which is wholly controlled by contact with or close proximity to the edges of the die. The edge of the die which is in contact with a flat side of the bundle of threads is preferably sharp. When a closed die is used its base should not substantially exceed the total cross-sectional area of the filaments. The aperture may be of circular, oval, or polygonal shape, or may have re-entrant angles, Fig. 4; it may be tapered. Two dies in series may be employed. To avoid threading of the filaments, a die may be made in parts so that it can be closed about them. Fig. 9 shows two plates which can be bolted together and have notches 40, 41 the apices of which register so as to form the die. In another form blocks 47, 48, Fig. 10, have tapered grooves 45, 46 which together constitute the die aperture. The filaments may be rendered sticky by heat, by a solvent or softener, or by both means, or they may be combined after their production and while still sticky by reason of residual solvent, or of the presence of substances such as vinyl acetate added to the spinning solution. They may be treated with the solvent or softener individually or while associated as a twisted or untwisted thread or as a plurality of threads, and continuously with their production by wet or dry spinning or during a winding, or twisting and winding, operation. Solvents suitable for filaments of cellulose acetate or other organic derivatives are: acetone, acetone-water, ethylene dichloride, ethyl or methyl alcohol, diacetin, triacetin, ethyl lactate, diacetone alcohol with or without water or alcohol, dibutyl tartrate, tricresyl phosphate, or mixtures. A dye, or a metallic or coloured powder, may be incorporated in the solvent or softener. Coloured threads &c., fine metal wires or ribbons, or threads having different dyeing properties from the remainder, may be embodied in the compound thread. In one arrangement of apparatus, threads 15, Fig. 1, from bobbins 16 are associated at a guide 18 and pass p through a die 19 which arranges them compactly, over a wick 20 supplied with solvent, through the main die 22, through a drying chamber 23 for recovering the solvent and around a feed roller 24 to a bobbin 25 frictionally driven. The die 19 may be adjustable along the direction of travel of the filaments. It may be heated. Fig. 13 shows wicks 56, between which the filaments pass, mounted on blocks 51 carried by crossed levers 52 which are pressed together by weights on their lower arms. The solvent may, alternatively, be applied by spraying or as vapour. It should not be used in amount greater than is necessary for adhesion. Lubricants may be applied to remove stickiness before entering the last die or before winding, or the solvents may be washed off the products. The filaments may be stretched before or during passage through the die. Specifications 349,999 and 368,738 are referred to.