Patent GB-670346-A (GB)
Title: Improvements in and relating to the production of cellulose compounds
IPC: D06M11/28
Filed: 1949-03-30
Abstract: Water - insoluble, alkali - soluble cellulosic material is produced from a water-soluble cellulosic material obtained by reacting cellulose with sulphuric acid and cyanamide by impregnating the water-soluble cellulosic material with an aqueous alcoholic solution of a water-soluble salt of a polyvalent metal and drying the impregnated material.  The water-soluble cellulosic material may be obtained by the process of Specification 647,321 and is preferably in the form of yarn.  The water-soluble salt may be calcium chloride, aluminium chloride, ferric chloride or an ammoniacal solution of zinc chloride.  It must be applied in the form of a solution which will not dissolve the water-soluble cellulosic material, e.g. a solution in 50 per cent by volume aqueous alcohol.  The impregnation of the material may be carried out at 15-20 DEG  C. and, after washing, the impregnated material may be dried at 60-70 DEG  C.  The products are soluble in a weakly alkaline aqueous solution such as 0.1 per cent sodium carbonate solution or one-fifth normal ammonium hydroxide solution.  In the example a skein of regenerated cellulose yarn is impregnated with a mixture of 13 c.c. of 15 N sulphuric acid, 12 grams of ammonium sulphate and 30 c.c. of 30-33 per cent aqueous cyanamide solution for 2-3 minutes, hydroextracted, dried at 60 DEG C., baked for 2 minutes at 160 DEG  C., and washed in 50 per cent by volume ammoniacal aqueous alcohol until neutral.  Three separate parts of the treated skein are then respectively treated with 0.5 per cent solution in 50 per cent by volume aqueous alcohol of calcium chloride, aluminium chloride and ferric chloride for 15 minutes at 16 DEG  C., rinsed in 50 per cent by volume aqueous alcohol and dried at 60 DEG  C.  The products are said to be fire-resistant.  When in the form of yarn they are said to be suitable for use as carrier yarn or as a core yarn in the production of effect threads or fabrics. Specification 634,690 also is referred to.ALSO:Cellulose textile material, particularly in the form of yarn, is reacted with sulphuric acid and cyanamide to produce a water-soluble product which is rendered water-insoluble, while remaining alkali-soluble, by impregnating it with an aqueous alcoholic solution of a water-soluble salt of a polyvalent metal and drying the impregnated material.  The water-soluble cellulosic material may be obtained by the process of Specification 647,321.  The water-soluble salt may be calcium chloride, aluminium chloride, ferric chloride or an ammoniacal solution of zinc chloride.  It must be applied in the form of a solution which will not dissolve the water-soluble cellulosic material, e.g. a solution in 50 per cent by volume aqueous alcohol. The impregnation of the material may be carried out at 15-20 DEG  C. and, after washing, the impregnated material may be dried at 60-70 DEG  C.  The products are soluble in a weakly alkaline aqueous solution such as 0.1 per cent sodium carbonate solution or one-fifth normal ammonium hydroxide solution.  In the example a skein of regenerated cellulose yarn is impregnated with a mixture of 13 c.c. of 15 N sulphuric acid, 12 grams of ammonium sulphate and 30 c.c. of 30-33 per cent aqueous cyanamide solution for 2-3 minutes, hydroextracted, dried at 60 DEG  C., baked for 2 minutes at 160 DEG C. and washed in 50 per cent by volume ammoniacal aqueous alcohol until neutral.  Three separate parts of the treated skein are then respectively treated with 0.5 per cent solutions in 50 per cent by volume aqueous alcohol of calcium chloride, aluminium chloride and ferric chloride for 15 minutes at 16 DEG  C., rinsed in 50 per cent by volume aqueous alcohol and dried at 60 DEG  C.  The products are said to be fire resistant.  When in the form of yarn they are said to be suitable for use as carrier yarn or as a core yarn in the production of effect threads or fabrics. Specification 634,690 also is referred to.