Method for preparing coating starch

Abstract

The invention provides a method for preparing coating starch. The method comprises the following steps: (1) oxidation modification, in which, after 200 weight portions of starch and 300 weight portionThe invention provides a method for preparing coating starch. The method comprises the following steps: (1) oxidation modification, in which, after 200 weight portions of starch and 300 weight portions of distilled water are evenly mixed, the starch and the distilled water are moved into a three-neck flask, pH value of starch slurry is adjusted to be 9.8-10.0 by a 3 percent sodium hydroxide solutis of distilled water are evenly mixed, the starch and the distilled water are moved into a three-neck flask, pH value of starch slurry is adjusted to be 9.8-10.0 by a 3 percent sodium hydroxide solution, and sodium hypochlorite solution accounting for 15 to 20 percent of the starch by weight is added into the starch slurry to perform an oxidation reaction at room temperature for 2 to 4 hours; (2)on, and sodium hypochlorite solution accounting for 15 to 20 percent of the starch by weight is added into the starch slurry to perform an oxidation reaction at room temperature for 2 to 4 hours; (2)crosslinking modification, in which, the pH value of the starch slurry is adjusted to be 11.0-11.2 by the 3 percent sodium hydroxide solution, and sodium trimetaphosphate accounting for 0.5 to 1 percecrosslinking modification, in which, the pH value of the starch slurry is adjusted to be 11.0-11.2 by the 3 percent sodium hydroxide solution, and sodium trimetaphosphate accounting for 0.5 to 1 percent of the starch by weight is added into the starch slurry to perform a crosslinking reaction at room temperature for 0.5 to 2 hours; (3) oxidation modification, in which, sodium hypochlorite solutionnt of the starch by weight is added into the starch slurry to perform a crosslinking reaction at room temperature for 0.5 to 2 hours; (3) oxidation modification, in which, sodium hypochlorite solutionaccounting for 15 to 20 percent of the starch by weight is added into the starch slurry to perform the oxidation reaction at room temperature for 2 to 4 hours, and chlorine is removed; and (4) the pH accounting for 15 to 20 percent of the starch by weight is added into the starch slurry to perform the oxidation reaction at room temperature for 2 to 4 hours, and chlorine is removed; and (4) the pH value of the starch slurry is adjusted to be 6.2-6.3 by a dilute hydrochloric acid solution, and the coating starch finished product can be obtained through dehydrating, drying and crushing. The methvalue of the starch slurry is adjusted to be 6.2-6.3 by a dilute hydrochloric acid solution, and the coating starch finished product can be obtained through dehydrating, drying and crushing. The method has the advantages that the coating starch prepared by the method can replace about 30 percent of latex, improve quality of paper making, reduce cost, and contribute to environmental protection.od has the advantages that the coating starch prepared by the method can replace about 30 percent of latex, improve quality of paper making, reduce cost, and contribute to environmental protection.

Description

technical field [0001] The invention relates to a method for preparing coated starch, which relates to a method for preparing starch for papermaking. Background technique [0002] The paper industry now generally uses oxidized starch and enzyme-converted starch as auxiliary adhesives. These starches have disadvantages such as poor heat resistance, poor water retention, and poor rheology of coatings. In order to overcome the above shortcomings, people continue to develop new starches and their preparation methods. Contents of the invention [0003] The technical problem to be solved by the present invention is to provide a method for preparing coated starch in order to overcome the above disadvantages. The invention adopts oxidation-crosslinking-oxidative denaturation to prepare coated starch, and the starch has the advantages of good heat resistance, good water retention, good rheological property of paint and the like. [0004] The present invention adopts the following ...

AI Technical Summary

Problems solved by technology

[0002] The paper industry now generally uses oxidized starch and enzyme-converted starch as auxiliary adhesives. These starches have shortcomings such as poor heat resistance, poor water retention, and poor rheology of coatings. In order to overcome the above-mentioned shortcomings, people continue to develop new starches and their preparation methods.