The quality of pulp is mainly determined by its fiber morphology and fiber purity. The properties of these two aspects are mainly determined by the variety of raw materials used, as well as the manufacturing method and processing depth.
In terms of fiber morphology, the main factors are the average length of fibers, the ratio of fiber cell wall thickness to cell lumen diameter, and the content of non-fibrous hybrid cells and fiber bundles in the pulp. Generally, the average fiber length is large, the ratio of cell wall thickness to cell diameter is small, and the pulp with no or few non-fibrous hybrid cells and fiber bundles has good bonding strength, dehydration and papermaking properties, and can produce stronger paper. Higher grade pulp, such as spruce softwood pulp, cotton and linen pulp, etc.
In terms of fiber purity, pulp with high cellulose content and low content of other components is generally better. This kind of pulp has high durability, strong binding force, high whiteness and good electrical insulation and other excellent properties.
Different uses and grades of paper have different requirements for pulp quality. It is not necessary to choose pulp with the best fiber shape and highest fiber purity. And the cheapest variety. Commercially and in production, various pulp quality inspection indicators are often formulated according to different use requirements, such as pulp brightness, water freeness, sieving fraction, resin and ash content, cellulose content, hardness (representing lignin content) , the physical strength of the pulp sheet and other indicators that affect the performance of the finished product. These indicators are actually specific reflections of the pulp’s fiber morphology and its purity. In the production of paper, either a suitable pulp can be selected, or two or more pulps of different qualities can be selected in an appropriate proportion.
Post time: Sep-03-2022