Modified starch and its preparation method and application

Abstract

The present invention relates to a kind of modified starch and its preparation method and application, mainly prepared by starch aqueous solution and cationic starch complexing agent; The chemical structure of described cationic starch complexing agent is made up of the following parts: i) one or more hydrophobic Group, wherein at least one hydrophobic group can react with starch to generate an inclusion complex, and ii) one or more hydrophilic groups, wherein at least one hydrophilic group is a cationic hydrophilic group; The group and the hydrophilic group are respectively located at the two ends of the same molecular structure and connected by chemical bonds to form an asymmetric and polar structure. The use of the modified starch in papermaking can greatly increase the adsorption rate of starch on the fiber surface or in pulp, thereby increasing the retention rate of starch in paper, thereby improving the strength of paper, and reducing or even eliminating the adsorption of starch in the pulp and papermaking process. Loss, thereby reducing COD emissions.

Description

Technical field [0001] The present invention relates to papermaking and starch modification techniques, and more particularly to a modified starch and a preparation method thereof. Background technique [0002] Starch is a natural polymer carbohydrate, existing in seeds, stems or roots of plants, abundant resources, low price, widely used in industrial, food, textile, paper, feed, medicine, architecture, drilling and other industries . Starch is one of the most important raw materials on papermaking. From the weight, it is often the fourth largest component of paper and cardboard, second only to cellulose, inorganic filler and moisture. Culture and packaging paper and paper version are the main users of starch. The consumption of paper industrial starch in the world is about 5 million tons, according to the total output of world paper and paper, the amount of starch consumption is about 1.6%. [0003] China's paper production has maintained rapid development in the past 30 years....

AI Technical Summary

Problems solved by technology

The above methods have disadvantages. The cationic starch produced by the wet method not only consumes a lot of water, but also the discharged sewage pollutes the environment. The wastewater is difficult to treat, and the alkaline chemicals used can lead to starch degradation and transformation. low rate

Dry production is to mix starch with reactive chemical reagents, dry to almost anhydrous and then react at 120-150°C. Although the pollution is less, the disadvantages are low reaction conversion rate, relatively high requirements for equipment and technology, and high production costs. , production conditions are difficult to control, starch products are easily over-gelatinized, which affects product quality, and the reaction cycle is long and energy consumption is high; the organic solvent method uses a large amount of water-soluble organic solvents (such as methanol, ethanol, isopropanol, etc.) in the preparation process ), disperse the starch in it to form a slurry, and react with the cationizing agent to prepare the cationic starch

Due to the use of a large amount of organic solvents, this method has the disadvantages of high production cost, poor safety, and easy pollution of the environment, so it is rarely used in industry.

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