GB366070A - Improvements in or relating to the production of artificial filaments or threads - Google Patents

Abstract

For the production of artificial filaments of large cross section by the union of a number of smaller filaments of cellulose acetate or other cellulose esters or ethers, the desired sticky or tacky condition necessary to ensure coalescence of the individual filaments is obtained by the application of a liquid having a solvent or softening action on the filaments and containing a high boiling solvent or plastifier; or, alternatively, the filaments are brought to a sticky or tacky condition by the application of a liquid having solvent or softening action, which liquid may or may not contain a high boiling solvent or plastifier, and thereafter union of the filaments is effected by the application of heat. The individual filaments may be from 2-25 deniers, they may be in the form of twisted or untwisted yarn or thread; and the union of the filaments may take place continuously with the production of the filaments or as a separate operation. Suitable solvent mixtures are acetone, ethylene dichloride and ethyl or methyl alcohol, or dichlorethylene and ethyl or methyl alcohol; and with these there may be used as high boiling solvent or plastifier, triacetine, diacetine, diethyl phthalate, dibutyl tartrate or tricresyl phosphate; and diluent liquids such as water or ether may also be added. In the solvent liquid there may be dissolved a proportion of an organic derivative of cellulose. The solvent liquid may be applied by wicks, rolls or rods, or by spraying; or the yarn or filaments may be immersed therein. When heat is employed to effect the union of the filaments, the latter may be heated prior to or during coalescence; and the heating may take place during the passage of the filaments through a heated chamber, or while they are passing over a heated roller or surface. According to the temperature and conditions so filaments completely or only partly coalesced may be obtained. In some cases it is an advantage especially if heat is used to unite the filaments, to add high boiling solvents or plastifiers to the spinning solutions. The union of the filaments may take place at intervals only along their length as by the intermittent application of the softening liquid, as described in Specification 325,823, [Class 2 (ii), Cellulose &c.], and such filaments may be flattened in the manner described in Specification 328,312, [Class 2 (ii), Cellulose &c.]. To produce colour effects, dyestuffs may be dissolved in the solvent liquid, or the materials may be dyed or coloured prior or subsequent to coalescence, preferably by the employment of solutions of dyestuffs in organic solvents as described in Specification 313,451, [Class 2 (ii), Cellulose &c.]. Suitable dyestuffs are 1 : 4-dimethyldiamino anthraquinone, rosaniline hydrochloride, and Cresyl Blue. The products may be delustred or rendered opaque either continuously along their length or intermittently, as by the action of water, steam, alcohol, &c., or by the application of a soluble salt of barium, strontium, calcium or other metal either in the solvent or softening liquid or as a separate treatment, followed by a treatment that precipitates an insoluble metal compound. Natural silk, wool, cotton, reconstituted cellulose or other yarns, or metal strips or metallized threads may be associated with the filaments to be coalesced; and metal powder &c. may be incorporated at any stage of the manufacture. Specifications 349,999 and 354,233 also are referred to.