In recent years, paper manufacturers and users have paid more and more attention to the volume of paper, because volume has a large impact on the cost and performance of the product. High bulk density means that at the same thickness, the basis weight can be reduced and the amount of fiber used can be reduced, so as to achieve the purpose of saving costs; the large capacity can increase the stiffness of the paper, allowing book publishers to maintain complete books with fewer pages Thickness can also increase paper opacity, printability and reduce leakage of printing ink. Therefore, Takamatsu is of great significance to the cost control of paper, product performance and product added value.
What is high volume? This is an important index of paper, that is, the ratio of basis weight to thickness. The volume represents the density of the paper, that is, the size of the porosity of the paper.
The main factors affecting the volume of paper include paper fiber raw material, pulp type, beating operation, filler, chemicals, pressing, drying, calendering, etc.
The fiber morphology of the papermaking fiber raw material has an important influence on the bulk density of the paper. Thicker fibers have higher porosity and higher bulk density of paper, but bulk density is not only related to fiber thickness, but also has a very important relationship with fiber breakage in the papermaking process. It ultimately depends on how much the fibers are broken and deformed. Therefore, fibers with a small diameter and a thick wall are hard, not easily crushed, and easily form high-bulk density paper.
The type of pulp also has a great impact on the volume of the paper. Generally speaking, high yield pulp > thermomechanical pulp > kraft pulp > waste pulp. Different raw materials have different volume in the same pulp, hardwood>softwood. The high bulkiness of high-yield pulp is unmatched by other pulps, so high-yield pulp is widely used to partially replace bleached kraft hardwood pulp in high-grade paper. The selection and ratio of pulp species are the key to the current high-loose paper production technology. Adding high-yield pulp to improve the bulk density of paper is currently the most effective method widely used by paper mills.
Volume is a very important characteristic of paper. High bulk density paper can maintain the necessary stiffness, reduce fiber consumption, save pulp costs and improve bulk density. The most viable methods currently include the addition of high yield pulp, pulp selection and process systems. The optimization and development of new bulk additives is also an important research direction.
Post time: Sep-14-2022