Brief description of application of modified starch in papermaking industry

The basic composition of paper products is cellulose. In the production process of paper, the fiber slurry containing more water is pressed to remove water so that the cellulose is tightly connected to achieve the best combination. For this reason, cellulose has to be ground into microfibers to increase the interlaced area, but over-refining will lose its inherent characteristics such as air permeability, flexibility and whiteness. If a certain kind of modified starch is added to the fiber slurry, it can not only maintain the inherent characteristics of the paper, but also add some special properties to the paper, such as increasing the tensile strength of the paper, increasing the gloss of the paper, and improving the ink resistance and printing performance. Reduces wear and hair loss. The modified starches used in the paper industry include hypochlorite oxidized starch, acid hydrolyzed starch, cationic starch, starch phosphate, and starch acetate. The most widely used is cationic starch, because cationic starch interacts with negatively charged cellulose and acts as an effective spot weld between cellulose, which has a significant effect on the quality of the paper. About 80% of paper mills in the United States use cationic starch. From the point of view of continuous improvement of paper quality requirements in various industries in China, there is great potential for demand for modified starch, especially cationic starch, in China's paper industry.

The main role of modified starch in the paper industry is as follows:

1. It is used to add wet paper to the paper before the paper is added, and a certain amount of gelatinized modified starch paste is added to make it work with fibers to enhance, aid, and retain. The addition of modified starch can improve the retention of fine fibers and fillers, increase the ash, whiteness and opacity of paper, and at the same time save energy, reduce the breakage of wet parts, and reduce the pollution of waste paper mills.

2. It is related to the surface properties, fiber structure, mixing ratio, beating degree, paper sheet moisture, etc. when the bond strength between layers is applied to the layers. The most widely used method for improving the bond strength between cardboards is to use modified starch granules for spraying. With a special nozzle, the squeegee is evenly sprayed on the paper layer. After drying, the starch granules are gelatinized and bonded.

3, surface sizing for paper can improve the sizing effect, saving the amount of sizing agent, in particular, can be used as a supporting agent for neutral papermaking.

4. It is used to apply coated paper to coat printing paper as adhesive, instead of expensive synthetic resin and casein, it can significantly reduce the production cost of coated paper.