Paper production process

(1) Pulping refers to the production process of removing non-fibrous materials from the cell walls of plants by mechanical or chemical methods or a combination of mechanical and chemical methods, that is, dissociating plant fiber raw materials to turn them into natural paper pulp or bleached paper pulp with fibers as the main body. The methods of making paddles can be classified into three types, namely mechanical method, chemical method and the combination of mechanical and chemical methods. Mechanical pulping is suitable for making newsprint, while chemical pulping is mainly used for high-grade paper, such as coated paper.

(2) Papermaking is a production process that further processes pulp to make it into a film-like substance. It first needs to go through paddling to separate the fiber bundles. Paddling will reduce the length of the fibers and lower the strength of the paper, so the paddling time should not be too long. Further filling, gluing and dyeing can be carried out. The filling process involves adding an appropriate amount of minerals and colorants to the pulp to achieve the physical properties required for the paper's application. Adding fillers can increase the smoothness of paper, enhance its opacity and whiteness, increase its thickness and weight, improve its ink absorption capacity and printing adaptability, etc. There are many types of fillers, among which the commonly used ones include Clay, asbestos, talc, gypsum, calcium carbonate (CaCO3), zinc sulfide and magnesium carbonate, etc., to fill the gaps between fibers. The gluing process mainly endows the paper with the ability to resist water penetration, and it can also enhance the hardness, toughness, tensile strength, moisture resistance of the paper, improve the smoothness of the paper surface and reduce fuzzing. At the same time, it also improves the printing adaptability of the paper. The types of glue used include Rosin, Starch, wax emulsion, etc. The purpose of the dyeing process is to improve the tone of the paper or increase its whiteness. Fluorescent materials are also used to convert the ultraviolet light shining on the paper into white light, thereby increasing the whiteness.