process for the production of kuenstlicher silk

摘要

Artificial silk of high tensile strength and improved flexibility is obtained by spinning, accompanied or followed by stretching, threads having a tensile strength above 2 gms. per denier, from cellulose esters other than nitrates, and then removing the ester groups completely, or to the extent of at least 10 per cent, from the formed threads. It is stated that spaces are thereby created between the cellulose crystallites. The threads of high tensile strength may be produced from an acetone solution of cellulose acetate by passing the spun threads through a solvent or swelling agent and subjecting to extension, or alternatively the solution of cellulose acetate may be spun into a mixture of a solvent with a non-solvent or coagulant, or into a swelling agent or a mixture of a swelling agent with a non-solvent or coagulant, and thereafter stretching the threads whilst in the plastic or semi-plastic state. These high tensile threads are then deacetylated, for example, by digesting with a solution of caustic soda for several hours, whereby they become finer in denier without appreciable loss in strength. Specifications 309,053, [Class 2 (ii), Cellulose &c.], and 344,873 are referred to.