Papermaking and products made thereby
AssigneeEKA Aktiebolag
InventorsOlof Sunden, Per G. Batelson, Hans E. Johansson, Hans M. Larsson, Per J. Svending
Life of this patent
Estimating the term…
Abstract
In making paper from an aqueous papermaking stock a binder comprising colloidal silicic acid and cationic starch is added to the stock for improving the paper or the retention of the stock components, or is added to the white water for reducing the pollution problems or recovering values from the white water. The cationic starch of the binder has a degree of substitution of not less than 0.01, and the weight ratio of cationic starch to SiO.sub.2 is between 1:1 and 25:1.
Claims37
In a paper making process in which an aqueous papermaking stock containing a sufficient amount of cellulosic pulp to give a finished paper containing at least 50% cellulosic fiber is formed and dried, the improvement which comprises providing in the stock prior to the formation of the sheet a binder comprising colloidal silicic acid having an average particle size of less than 20 nm, and cationic starch having a degree of substitution of not less than 0.01, the weight ratio of cationic starch to SiO.sub.2 being between 1:1 and 25:1, the solids in said binder amounting to 0.1-15% of the weight of said pulp, said cationic starch and said colloidal silicic acid being admixed with each other in the presence of cellulosic fiber to form a complex of cationic starch and colloidal silicic acid which serves as a binder for the cellulosic fibers.
In a papermaking process in which an aqueous papermaking stock containing a sufficient amount of cellulosic pulp to give a paper containing at least 50 percent of cellulosic fiber is formed and dried, the improvement which comprises providing in the stock prior to the formation of the sheet a binder comprising a colloidal silica sol having silica particles having a surface area of about 50 to about 1000 m.sup.2 /g and cationic starch having a degree of substitution of not less than 0.01, the weight ratio of cationic starch to SiO.sub.2 being between 1:1 and 25:1, the solids in said binder amounting to 0.1-15% of the weight of said pulp, said cationic starch and said colloidal silica sol being admixed with each other in the presence of cellulosic fiber to form a complex of cationic starch and colloidal silica which serves as a binder for the cellulosic fibers.
In a papermaking process in which an aqueous papermaking stock containing a sufficient amount of cellulosic pulp to give a paper containing at least 50 percent of cellulosic fiber and a mineral filler material having at least partial anionic surface characteristics is formed and dried, the improvement which comprises providing in the stock prior to the formation of the sheet a binder comprising colloidal silicic acid having an average particle size of less than 20 nm and cationic starch having a degree of substitution of not less than 0.01, the weight ratio of cationic starch to SiO.sub.2 being between 1:1 and 25:1, the solids in said binder amounting to from about 0.5-25% of the weight of said mineral filler material, said cationic starch and said colloidal silicic acid being admixed with each other in the presence of cellulosic fiber and mineral filler to form a complex of colloidal silicic acid and cationic starch which serves as a binder for the cellulosic fibers and mineral filler.
In a papermaking process in which an aqueous papermaking stock containing a sufficient amount of cellulosic pulp to provide a paper having at least 50 percent of cellulosic fiber and a mineral filler material having at least partial anionic surface characteristics is formed and dried, the improvement which comprises providing in the stock prior to the formation of the sheet a colloidal silica sol having silica particles having a surface area of about 50 to about 1000 m.sup.2 /g and cationic starch having a degree of substitution of over about 0.01 to about 0.05, the weight ratio of cationic starch to SiO.sub.2 being between 1:1 and 25:1, the solids in said binder amounting to from about 0.5-25% of the weight of said mineral filler material, said cationic starch and said colloidal silica sol being admixed with each other in the presence of cellulosic fibers and mineral filler to form a complex of colloidal silica and cationic starch which serves as a binder for said cellulosic fibers and mineral filler.
An improved cellulosic paper product comprising at least 50 percent cellulosic fiber characterized by enhanced strength characteristics wherein the bond between cellulosic fibers is enhanced by a binder comprising a complex of colloidal silicic acid having an average particle size of less than 20 nm and cationic starch having a degree of substitution of over about 0.01 and wherein the ratio of cationic starch to SiO.sub.2 is between 1:1 and 25:1, the solids in said binder amounting to 0.1-15% of the weight of the cellulosic fiber.
An improved cellulosic paper product characterized by enhanced strength characteristics wherein the bond between cellulosic fiber is enhanced by a binder comprising a complex of a colloidal silica sol having silica particles having a surface area of about 50 to about 1000 m.sup.2 /g and cationic starch having a degree of substitution of over about 0.01 and wherein the ratio of cationic starch to SiO.sub.2 is between 1:1 and 25:1, the solids in said binder amounting to 0.1-15% of the weight of said cellulosic fiber.
An improved cellulosic paper product containing at least 50 percent of cellulosic fiber, and a mineral filler having at least partial anionic surface characteristics wherein the bond between the cellulosic fibers and the mineral filler material is enhanced by a binder comprising a complex of a colloidal silicic acid having an average particle size of less than 20 nm and cationic starch having a degree of substitution of over about 0.01 and wherein the ratio of cationic starch to SiO.sub.2 is between 1:1 and 25:1, the solids in said binder comprising 0.5-25% of the weight of said mineral filler material.
An improved cellulosic paper product containing at least 50 percent cellulosic fiber, and a mineral filler having at least partial anionic surface characteristics wherein the bond between the cellulosic fibers and the mineral filler material is enhanced by a binder comprising a complex of colloidal silica sol having silica particles having a surface area of about 50 to about 1000 m.sup.2 /g and cationic starch having a degree of substitution of over 0.01 and wherein the ratio of cationic starch to SiO.sub.2 is between 1:1 and 25:1, the solids in said binder comprising 0.5-25% of the weight of said mineral filler material.
Dependencies are inferred from the claim text.