GB525738A - Improvements in or relating to the manufacture of artificial threads strips or bandsfrom protein solutions - Google Patents

Abstract

525,738. Artificial filaments &c. NAAMLOOZE VENNOOTSCHAP ONDERZOEKINGSINSTITUUT RESEARCH. Feb. 27, 1939, No. 6462. Convention date, March 29, 1938. [Class 2 (ii)] Artificial threads, strips, or bands are produced from an alkaline protein solution by extruding the solution into an acid spinning bath, and the freshly formed threads or other products are subjected to a continuous operation comprising a treatment with one or more hot salt solutions and a stretching by means of driven rollers or godets, the peripheral 'speed of each roller being greater than that of the preceding roller in the series. Stretching of the thread takes place while it is in contact with the hot salt solution. The thread is subsequently hardened with formaldehyde while it is in an untensioned state. When more than one salt solution is used these may be of different concentrations and at different temperatures. Salt solutions used include sodium sulphate, magnesium sulphate, zinc sulphate, aluminium sulphate, and sodium acetate. The thread may be cut to staple fibres before the formaldehyde treatment. In an example, a solution of casein in caustic soda solution is spun into a warm bath of dilute sulphuric acid, magnesium sulphate and sodium sulphate. The thread obtained is passed over a series of rollers rotating at increasing peripheral speeds, each roller being immersed in a hot solution of sodium sulphate. The thread is cut to staple fibre and treated with formaldehyde. If the temperature of the salt bath is sufficiently high the thread becomes stabilized so that it does not shrink during the subsequent hardening process. If the temperature of the salt bath. is below 80‹C., the bundle of filaments may be stabilized by passing it after the stretching treatment through another bath by means of rollers having the same speed as the last of the stretching rollers.