Chemical pulp: Extracting pulp from wood using chemical methods. In the papermaking process, the pulp made mainly of chemicals, of course, has certain differences depending on the chemicals used and the manufacturing method. But they all have the disadvantages of low raw material utilization rate and high production cost. It is mainly used for high-grade printing paper, copy paper, computer paper, offset paper, cover paper, writing paper and paper bag paper, etc.

Mechanical pulping: Mechanical pulping mainly utilizes the friction and tearing effect of the mechanical rotating friction working surface on the fiber raw material, and the heating, softening, and plasticizing effect of the heat generated by the friction on the raw material ligning to separate the raw material into a single fiber. Mechanical pulping hardly dissolves lignin in raw materials, so the pulping yield is very high, generally around 95%, and does not consume chemicals. It is a pulping method with the lowest production cost. Mechanical pulp has the advantages of a relatively simple production process, low cost, high yield, less pollution, good printing performance of finished paper, good smoothness, and high opacity. However, due to the great damage caused by the friction and tearing of the fibers during the production process, the physical strength of mechanical pulp is lower than that of other pulps, and a large amount of lignin is retained in mechanical pulp, so it is difficult to bleach and easy to be exposed to light and heat. Turn yellow and become brittle.

Chemical-mechanical pulp: also called the semi-chemical pulp, the delicious effect in the chemical cooking process is not sufficient, the fibers are not completely separated, and the pulp needs subsequent mechanical treatment. The semi-chemical pulp process has room for adjustment, and the pulping yield is 65%-85%. It can be used to manufacture corrugated cardboard, and can also be used to produce advanced fully bleached pulp.

Lignin

Lignin is mainly located between cellulose fibers and acts as an anti-compression. Why can't the base paper using complete mechanical pulp when making high-grade coated paper, in mechanical pulp, lignin is not separated, and when making high-grade printing paper, the color developer in the chemical coating will double with lignin Phenol reaction leads to poor color development of the final high-grade printing paper, especially heat-sensitive paper, and the lignin in the chemical pulp has been removed so that no chemical reaction will occur. That's why when making thermal paper, the base paper never chooses mechanical pulp.