dosage of chitosan on water resistance of paper

Because chitosan has amino and carboxyl groups, it can be dissolved in dilute acid to form a high-viscosity colloidal solution. Its aqueous solution is a cationic electrolyte, which has good film-forming properties and high film strength, so it can be used for water resistance of paper. with antisolvent.

Chitosan is a high-molecular-weight linear substance with a molecular weight ranging from tens of thousands to several million. It has sufficient bonding strength to fibers and the ability to bridge between fibers, thereby enhancing and retaining paper. .

The molecular weight of chitosan is similar to that of cellulose, the chemical structure is similar to that of cellulose, and it is a straight-chain type. Water resistant. The above properties of chitosan make it very suitable as a surface sizing agent for paper.

Chitosan itself is also a preservative, used as a surface sizing agent for paper, and also plays a good role in preventing moth and mildew, so it is especially popular for the production of book printing paper.

Chitosan can also be compounded with gelatin, polyol-polyacid, etc., and can be made into a compound sizing agent. The special paper made is used for lithographic printing. The printing plate can absorb both water and ink. Before calendering, the capacitor paper is surface-treated with 0.3%-2% chitosan acetic acid solution, which can significantly improve the resistivity of the capacitor paper.

At present, the application of chitosan in the paper industry is for drying enhancement and retention of paper. As a drying enhancer for paper, it is generally believed that an ideal drying enhancer should have the following conditions: ① Linear macromolecules, so that the amino group can be sufficiently close to the fiber surface. ② The relative molecular mass is large, it has the ability to form film, and it has sufficient bonding strength to the fibers and can bridge between fibers. ③ There are many positive charge centers and carboxyl groups on the molecular chain, which is convenient to form electrostatic bonds and hydrogen bonds with fibers. Since chitosan fully meets the above conditions, it has a very good drying enhancement effect.