Patent GB-723215-A (GB)
Title: Process for the production of artificial filaments of protein
IPC: D01F4/00
Filed: 1951-06-29
Abstract: In the production of artificial filaments of globular water-insoluble proteins by wet-spinning of solutions of the proteins, the proteins, before dissolving them to prepare the spinning solution, are treated with at least one fatty tanning substance consisting of a highly unsaturated triglyceride fatty oil (and/or free fatty acid derived from such oil) containing one or more free and/or combined fatty acids having at least three carbon to carbon double bonds in the molecule, with or without a fatty oil or fatty acid of a lesser degree of unsaturation, a portion at least of the fatty tanning substances becoming " fixed " in the proteins, in the sense that it cannot be dissolved out from the dried proteins by treatment thereof with a solvent for the fatty tanning substance or substances.  The proteins, before spinning, may also be treated with water-soluble tin salts as described in Specification 723,214.  Filaments spun from protein treated as above or from untreated proteins or proteins treated with tin salts may be treated with a fatty tanning substance as defined above.  In an example 50 grams of whale oil are added dropwise to a mixture of 1000 grams of lactic casein and 2500 c.c. of water and the mixture stirred for 5 hours.  450 c.c. of water are then stirred in and after an hour 1250 c.c. of water containing 200 c.c. of an aqueous solution of sodium hydroxide of density 1.330, to dissolve the protein.  The temperature throughout is 20 DEG  C.  In other examples lactic casein is similarly treated except that the casein is first mixed not with water alone but with emulsions of whale oil and water at 20 DEG , 50 DEG  and 70 DEG  C. In further examples casein is similarly treated with emulsions in which 15 per cent by weight of the whale oil is substituted by degras recovered from chamois leather which has been tanned with fish oils.  The tests are repeated using zein, peanut, and soya bean proteins, sulphuric acid casein and rennet casein in place of lactic casein.  In other tests whale oil is substituted by seal oil, bleached cod liver oil, sardine oil and herring oil, by free fatty acids obtained from these oils and by fatty acids obtained from tung oil and linseed oil.  In a further example 1000 grams of lactic casein are mixed for 5 hours with a mixture of an emulsion of 50 gr. of whale oil in 1000 gr. of water with 1500 c.c. of an aqueous solution containing 6 gr. of stannous chloride and 60 c.c. of aqueous stannic chloride solution of density 1072.  500 c.c. of water are then added followed by 750 c.c. of a mixture of 200 c.c. of sodium hydroxide solution of density 1.330 and 550 c.c. of water.  Filaments spun from proteins which have not been treated with fatty tanning substances or with only a limited proportion thereof, after hardening in a saline bath with formaldehyde may be centrifuged to decrease the proportion of saline liquor adhering to them and then treated with (preferably hot) emulsions of water and fatty tanning substances, the proportion of emulsion preferably not exceeding 50 per cent by weight of the filaments. The treatment may be carried out in tanning vats at 50-60 DEG  C. and the filaments then kept for a few days in heated rooms, e.g. at 40 DEG  C.  They may then again be treated in a saline hardening bath containing formaldehyde at 70/75 DEG  C. for 7-10 hours, washed and dried.  The filaments may be treated with a proportion of fatty tanning substances greater than that necessary to saturate them and the surplus tanning emulsion eliminated by alternate centrifuging and washing with water at 50-60 DEG  C. followed by washing with slightly alkaline water at 20-30 DEG  C., centrifuging, and washing in cold water.  The treated filaments are then dried at 70-100 DEG  C.  Alternatively to treatment with fatty tanning substances emulsions the filaments (preferably after having been allowed to absorb from the atmosphere at least 5 per cent of moisture) are immersed in fatty tanning substances such as whale oil which has not been emulsified, preferably in revolving tanning vats. The filaments are then centrifuged and kept for a few days in a room, preferably heated to 30-40 DEG  C.  The whale oil and/or other fatty tanning substances may be partially substituted by natural and/or artificial degras.  The proteins after treatment with fatty tanning substances and dissolving in aqueous sodium hydroxide solution may be spun into aqueous coagulating baths containing aluminium sulphate, sodium sulphate and sulphuric acid.  The filaments may then be stretched, passed successively through an aqueous solution of sodium chloride and aluminium sulphate at 25-40 DEG  C. and a second aqueous saline solution containing sodium chloride, urea, and a higher proportion of aluminium sulphate at 25-60 DEG  C.  The filaments are then stretched, cut into fibres and hardened in solutions of sodium chloride, aluminium sulphate and formaldehyde in water contained in closed digesters, the initial temperature being 20-35 DEG  C. and the final temperature 70-100 DEG  C. after 3-7 hours.  The process of the invention improves the elasticity of the filaments and renders them water-repellent.ALSO:Globular water-insoluble proteins are treated with at least one "fatty tanning substance" consisting of a highly unsaturated triglyceride fatty oil (and/or free fatty acids derived from such oil) containing one or more free and/or combined fatty acids having at least three carbon to carbon double bonds in the molecule, with or without a fatty oil or fatty acid of a lesser degree of unsaturation, a portion at least of the fatty tanning substance becoming "fixed" in the proteins, in the sense that it cannot be dissolved out from the dried proteins by treatment thereof with a solvent for the fatty tanning substance.  The treated proteins may be dissolved to form spinning solutions (see Group IV (a)).  The proteins may be treated, in addition to the fatty tanning substances, with water-soluble tin salts (see Specification 723,214).  The fatty substance may be in the form of an aqueous emulsion and may contain degras and may be a fish oil or blubber oil, e.g. whale oil.  In an example a mixture of lactic casein and water is stirred for 5 hours with whale oil, more water added and the casein then dissolved by the addition of an aqueous solution of sodium hydroxide.  In other examples lactic casein is mixed with an emulsion of whale oil and water at 20 DEG  C., 50 DEG  C. and 70 DEG  C. respectively.  The protein may be zein, peanut or soya bean protein, sulphuric acid casein, or rennet casein.  The fatty substance may be whale oil, seal oil, bleached cod liver oil, sardine oil or herring oil; fatty acids obtained from those oils or fatty acids obtained from tung oil or linseed oil.