Patent GB-692876-A (GB)
Title: Improvements in and relating to the production of regenerated keratin threads, fibres, filaments and the like
Inventor: HAPPEY FRANK
IPC: D01F4/00
Filed: 1950-10-12
Abstract: Regenerated keratin threads are produced by oxidizing keratin with an acid aqueous solution of hydrogen peroxide and ferrous sulphate, dissolving the oxidized keratin in an aqueous alkaline solution and extruding the solution into an aqueous coagulating bath.  Phosphoric, acetic, or preferably sulphuric acid may be used in the oxidation. The proportion of hydrated ferrous sulphate used may be 2-20 and preferably 8-10 per cent by weight of the keratin.  The proportion of acid used may also be 2-20 per cent by weight of the keratin and should be sufficient p  to prevent the precipitation of iron hydroxides, e.g. approximately equal parts by weight of hydrated ferrous sulphate and sulphuric acid.  The alkaline solution used may be aqueous ammonia or aqueous caustic soda solution.  The coagulating bath may be an aqueous solution of sodium and/or magnesium and/or aluminium sulphate, the pH of the bath being preferably 5.0-9.0. The threads may be stretched at least 50 and preferably 100-300 per cent in air or in a coagulant bath free from hardening agents. The stretched threads may be treated in the hardening baths usually employed for casein threads, e.g. aqueous formaldehyde, preferably in conjunction with one or more metal salts such as sodium sulphate, magnesium sulphate, aluminium sulphate, calcium chloride, zinc chloride, basic chromium sulphate and zirconyl sulphate.  After hardening, the threads are preferably insolubilized, preferably using formaldehyde and sodium bisulphate (see Specification 549,642).  The hardened threads may be subsequently further stretched and hardened (see Specification 502,710).  In an example, 100 grams of wool waste are treated for 16 hours at 20 DEG  C. with 1500 c.c. of 100 vol. hydrogen peroxide containing 13.5 grams of sulphuric acid and 8 grams of ferrous sulphate (as FeSO4.7H2O).  The product is washed, dissolved in dilute aqueous ammonium hydroxide solution, precipitated by addition of dilute sulphuric acid solution and dissolved in concentrated ammonia solution.  The oxidized keratin solution thus obtained is extruded into a neutral aqueous solution of magnesium and sodium sulphates, the extruded threads are stretched 200 per cent, hardened and insolubilized.  The keratin used may be rabbit down. Specification 690,566 also is referred to.ALSO:Keratin is prepared for use in the manufacture of artificial threads (see Group IV (a)) by oxidation with an acid aqueous solution of hydrogen peroxide and ferrous sulphate.  The acid may be phosphoric, acetic or preferably sulphuric acid.  The proportions of (hydrated) ferrous sulphate and of sulphuric acid used may be 2-20 and preferably 8-10 per cent by weight of the keratin.  In an example, 100 grams of wool waste are treated for 16 hours at 20 DEG  C. with 1500 c.c. of 100 vol. hydrogen peroxide containing 13.5 grams of sulphuric acid and 8 grams of ferrous sulphate (as FeSO4.7H2O).  The product is washed with water, dissolved in dilute aqueous ammonia, the solution filtered and the oxidized keratin precipitated by acidification with dilute sulphuric acid.  The precipitate is filtered and washed and may be dissolved in concentrated ammonia to form a spinning solution.