GB1400028A - Synthetic fibre end tapering method - Google Patents

Abstract

1400028 Tapering bristles PENTEL K K 9 Oct 1972 46396/72 Heading A4K [Also in Divisions B6 and D1] Acryl, nylon or polyester synthetic fibres are tapered by forming them into a bundle and subjecting the end portion of the bundle to the action of an etching liquid applied more effectively to the tip part than to the upper part of the end portion. The tip part may for example be rubbed against a surface, such as an etchant container bottom or a needle-studded plate moving in the etchant, or a jet of etchant may be directed at right-angles to the fibres with greater strength against the tip portion. The portion other than the end portion of the bundle may be protected by application of an adhesive or impregnation with a liquid resistant to the etchant. After etching, a second liquid may be applied to remove dissolved portions of the fibres and to remove traces of etchant, and the second liquid may be the same as the etchant but either more diluted or at a lower temperature. The bundle may be further washed in a third liquid. Examples of the etchant are:- for nylon fibres; m-cresol and methanol solution of calcium chloride, heated methanol solution of calcium chloride, p-toluenesulphonic acid, formic acid, acetic acid, alcohol solution of zinc chloride, phenol, xylenol, hot benzyl alcohol, ethylenic chlorohydrin, hydrochloric acid, sulphuric acid, nitric acid, phosphoric acid: for acryl fibres; hot dimethylformamide, hot dimethylsulphoxide: for polyester fibres; phenol, dichloroacetic acid, trichloroacetic acid with ethane tetrachloride, methylene chloride, trichloroethylene, acetic acid, acetone: singly or in combination. The second liquid may be (a) the etchant diluted with alcohols such as methanol or ethanol, ketones such as acetone or ethylmethylketone, esters such as methyl acetate or ethyl acetate, aromatic hydrocarbons such as toluene or xylene, or water, (b) the etchant used at a lower temperature, e.g. methanol solution of calcium chloride, dimethylformamide, dimethylsulphoxide, (c) a liquid soluble with the etchant but having no fibredissolving ability, e.g. methanol, ethanol, dimethylformamide, methylene chloride, trichloroethylene, used with fibres which they do not dissolve, e.g. dimethylformamide with nylon. Examples of the third liquid are methanol, ethanol, acetone, ethylmethylketone, methyl acetate, ethyl acetate, toluene, xylene, water.