Patent GB-1075492-A (GB)
Title: Degraded cellulose and its manufacture
IPC: A23L1/308
Filed: 1965-06-04
Abstract: Cleansing compositions in the form of pastes contain degraded (partially depolymerized) cellulose consisting of very finely divided amorphous particles insoluble in water but capable of forming colloidal aqueous dispersions as produced within a time not exceeding 10 minutes and at a temperature of about 35 DEG  to 45 DEG  C. by dissolving a native or a regenerated cellulose in a large excess of aqueous sulphuric acid containing 65 to 75%, preferably 70 to 73% by weight of sulphuric acid, diluting the solution with water, and separating the precipitate of degraded cellulose thereby formed from the acidic aqueous liquor.  The separated degraded cellulose may be washed with water and/or neutralized. The native cellulose used as starting material may be cotton linters or purified wool pulp.  The cleansing composition may be in the form of a paste and may also contain a small amount of ethyl alcohol or surfactant.  In an example, 20 grams of lauryl sulphate, 100 grams of 95% V/V concentration ethyl alcohol and 1000 grams of a paste consisting of water and degraded cellulose prepared from cotton linters according to the invention (the mixture containing about 15% by weight of water) are mixed together to form a hand cleaner.ALSO:Degraded (partially depolymerized) cellulose consisting of very finely divided amorphous particles insoluble in water but capable of forming colloidal aqueous dispersions is produced by, within a time not exceeding 10 minutes dissolving a native or a regenerated cellulose at a temperature of about 35 DEG  to 45 DEG  C. in a large excess of sulphuric acid containing 65 to 75%, preferably 70 to 73% by weight of sulphuric acid, diluting the solution with water, and separating the precipitate of degraded cellulose thereby formed from the acidic aqueous liquor. The separated degraded cellulose may be washed with water and/or neutralized. The native cellulose used as starting material may be cotton linters or purified wood pulp.  The dilution of the solution of cellulose in aqueous sulphuric acid to precipitate the degraded cellulose may be such that the concentration of acid in the solution is lowered to about 20 to 25% by weight of acid.  The viscosity of a solution of degraded cellulose prepared from cotton linters (according to the invention) in a standard aqueous cuprammonium solution 15 g./l. of copper and 200 g./l. of ammonia is about one-sixth to one fourth that of a micro-crystalline degraded cellulose known by the Trade Mark "Avirin".  In an example, 20 grams of lauryl sulphate, 100 grams of 95% v/v concentration ethyl alcohol and 1000 grams of a paste consisting of water and degraded cellulose prepared from cotton linters according to the invention (the mixture containing about 15% by weight of water) are mixed together to form a hand cleaner.  In an example, 66 grams of a paste consisting of a mixture of 10 grams of degraded cellulose and 56 grams of water are mixed with 1000 grams of calcium sulphate dihydrate and the mixture heated at 150 DEG  C. for 50 minutes to form a plaster of Paris which can be nailed without cracking.  In an example, 200 grams of a paste consisting of a mixture of water and degraded cellulose containing 15% by weight of the latter are mixed with 115 grams of sugar and a few drops of vanillin extract to form a low-calory cream substitute. In the event of the cellulose starting material being wet, its water content is allowed for when adjusting the concentration of the acid solution in which the cellulose is to be dissolved.ALSO:Calcium sulphate dihydrate is mixed with a past of degraded (partially depolymerized) cellulose and heated at 150 DEG  C. to form plaster of Paris.  The cellulose consists of very finely-divided amorphous particles insoluble in water but capable of forming colloidal aqueous dispersions, and is produced by dissolving a native or a regenerated cellulose at a temperature of about 35 DEG  to 45 DEG  C. in a large excess of aqueous sulphuric acid containing 65 to 75% by weight of sulphuric acid, diluting the solution with water, and separating the precipitate of degraded cellulose thereby formed from the acidic aqueous liquor.  The separated degraded cellulose may be washed with water and/or neutralized. The native cellulose used as starting material may be cotton linters or purified wood pulp.ALSO:Degraded (partially depolymerised) cellulose consisting of very finely divided amorphous particles insoluble in water but capable of forming colloidal aqueous dispersions is produced by, within a time not exceeding ten minutes dissolving a native or a regenerated cellulose at a temperature of about 35 to 45 DEG C. in a large excess of aqueous sulphuric acid containing 65 to 75%, preferably 70 to 73% by weight of sulphuric acid (the water content of the cellulose, if wet, having been allowed for when adjusting the concentration of the acid), diluting the solution with water, and separating the precipitate of degraded cellulose thereby formed from the acidic aqueous liquor.  The separated degraded cellulose may be washed with water and/or neutralised. The native cellulose used as starting material may be cotton linters or purified wood pulp.  The dilution of the solution of cellulose in aqueous sulphuric acid to precipitate the degraded cellulose may be such that the concentration of acid in the solution is lowered to about 20 to 25% by weight of acid.  The viscosity of a solution of degraded cellulose prepared from cotton linters (according to the invention) in a standard aqueous cuprammonium solution (15 g/l of copper and 200 g/l of ammonia is about one-sixth to one-fourth that of a micro-crystalline degraded cellulose known by the trade mark "Avirin."  In an example 200 grams of a paste consisting of a mixture of water and degraded cellulose containing 15% by weight of the latter are mixed with 115 grams of sugar and a few drops of vanillin extract to form a low-calory cream substitute.