Patent GB-356287-A (GB)
Title: An improved coating material for paper and process for preparing the same
IPC: D21H19/50
Filed: 1930-04-17
Abstract: In making a coating material for paper a vegetable protein is extracted from seeds by treatment with an alkaline reagent and thereafter subjected to a denaturing treatment, rendering it readily dispersed or dissolved in a weakly alkaline solution, for example a lime-containing liquid, even after having been dried. Oleaginous seeds such as soya bean, cotton seed, peanut, castor, tung nut and linseed, preferably after removal of the oil, are finely ground and treated with an aqueous alkaline reagent to extract the protein.  The alkaline agent may be a strong alkali such as caustic soda or, preferably, a weakly alkaline salt such as sodium sulphite or phosphate used at temperatures up to 120 DEG  F. After separation of insoluble matter the protein is denatured by adding lime to the liquor, separating the precipitate formed and allowing the resulting liquor to stand for about sixteen hours at 60 DEG  F. or for two hours at 120 DEG  F.  Alternatively, both the extraction of the protein and the subsequent denaturing treatment may be carried out with lime.  The protein is then precipitated by adjusting the hydrogen ion concentration of the liquor to about pH 4, for example by addition of dilute sulphuric acid at a temperature of about 120 DEG  F.  The precipitated curd is then drained, washed, pressed to remove part of the water, further dried at about 100 DEG  F., and ground.  The coating material is made by mixing the protein in a wet or dry state with water and weakly alkaline salts such as sodium carbonate, borax, sodium bisulphite and trisodium phosphate, heating to 120-150 DEG  F. and incorporating mineral bodying agents such as clay and satin white.  Hydrated lime may be added to form a water-resistant coating.ALSO:In making a coating material for paper a vegetable protein is extracted from seeds by treatment with an alkaline reagent and thereafter subjected to a denaturing treatment, rendering it readily dispersed or dissolved in a weakly alkaline solution, for example a lime-containing liquid, even after having been dried. Oleaginous seeds such as soya bean, cotton seed, peanut, castor, tung nut and linseed, preferably after removal of the oil, are finely ground and treated with an aqueous alkaline reagent to extract the protein.  The alkaline agent may be a strong alkali such as caustic soda or, preferably, a weakly alkaline salt such as sodium sulphite or phosphate used at temperatures up to 120 DEG  F. After separation of insoluble matter the protein is denatured by adding lime to the liquor, separating the precipitate formed and allowing the resulting liquor to stand for about sixteen hours at 60 DEG  F. or for two hours at 120 DEG  F.  Alternatively, both the extraction of the protein and the subsequent denaturing treatment may be carried out with lime.  The protein is then precipitated by adjusting the hydrogen ion concentration of the liquor to about pH 4, for example by addition of dilute sulphuric acid at a temperature of about 120 DEG  F.  The precipitated curd is then drained, washed, pressed to remove part of the water, further dried at about 100 DEG  F., and ground.ALSO:In making a coating material for paper a vegetable protein is extracted from seeds by treatment with an alkaline reagent and thereafter subjected to a denaturing treatment, rendering it readily dispersed or dissolved in a weakly alkaline solution, for example a lime-containing liquid, even after having been dried. Oleaginous seeds such as soya bean, cotton seed, peanut, castor, tung nut and linseed, preferably after removal of the oil, are finely ground and treated with an aqueous alkaline reagent to extract the protein.  The alkaline agent may be a strong alkali such as caustic soda or, preferably, a weakly alkaline salt such as sodium sulphite or phosphate used at temperatures up to 120 DEG  F. After separation of insoluble matter the protein is denatured by adding lime to the liquor, separating the precipitate formed and allowing the resulting liquor to stand for about sixteen hours at 60 DEG  F. or for two hours at 120 DEG  F.  Alternatively, both the extraction of the protein and the subsequent denaturing treatment may be carried out with lime.  The protein is then precipitated by adjusting the hydrogen ion concentration of the liquor to about pH 4, for example by addition of dilute sulphuric acid at a temperature of about 120 DEG  F.  The precipitated curd is then drained, washed, pressed to remove part of the water, further dried at about 100 DEG  F., and ground.  The coating material is made by mixing the protein in a wet or dry state with water and weakly alkaline salts such as sodium carbonate, borax, sodium bisulphite and trisodium phosphate, heating to 120-150 DEG  F. and incorporating mineral bodying agents such as clay and satin white.  Hydrated lime may be added to form a water-resistant coating.