GB317098A - Improvements in or relating to the manufacture of artificial filaments or threads - Google Patents

Abstract

317,098. Dreyfus, H. Feb. 6, 1928. Cellulose esters and ethers, processes for making filaments from.-For the manufacture of " hollow filament or fibres by the dry spinning method, there are employed solutions of organic derivatives of cellulose, particularly cellulose acetate, in volatile solvent mixtures containing both high and low boiling point, constituents, the boiling points differing by 35‹ C. or more, and spinning temperatures at or about the boiling point of the higher boiling point constituent, the temperature depending to some, extent on the relative proportions and boiling points of the constituents of the solvent mixture. Operating in this manner, the filaments can be distended without loss of strength, and they may also be drawn out to fine deniers. It is preferred that the boiling point difference should be 40‹ C., 50‹ C., 100‹ C. or even higher; if, however, the difference is between 35‹ and 40‹ C., then the lower boiling point constituent should comprise at least 50 per cent, preferably 75 per cent, of the solvent mixture. In examples, hollow filaments are obtained by spinning solutions of cellulose acetate in acetone-acetaldehyde at. 65‹ C., in acetoneacetaldehyde-alcohol at 70‹ C., in alcohol-methyl formate at 63‹ C. and 80‹ C., methyl formatecyclobutanone at 85‹ C., and in acetone-water at just below 100‹ C. The spinning solution may contain a high-boiling point solvent or plasticizer, and any plasticizer that remains in the filaments may be removed by extraction with alkaline solutions &c. Specifications 165,519, 182,166, 198,023, 203,092, 209,125, 210,108, and 317,097 are referred to.