The main cause of paper fuzzing and powdering is the low surface strength of the paper, which leads to poor bonding between fine fibers, fillers, and the primary fibers. As a result, these particles fall off the paper surface due to external friction. Therefore, the first step in eliminating fuzzing and powdering is to focus on improving the surface strength of the paper, which can be achieved by controlling the quality of the pulp and effectively using additives.
1. Pulp Quality Control
Long fibers in paper form the tensile framework of the sheet, and the quality and treatment of these fibers directly affect the strength of the paper. To enhance the surface strength, the wet weight and the degree of fiber fibrillation should be properly controlled. In actual production, increasing the pulping concentration and appropriately extending the pulping time can improve the treatment of long fibers. The use of wide and shallow-beveled refiner plates is also preferred to optimize the pulping of long fibers. Short fibers should be pulped based on the dewatering and drying conditions to ensure good bonding with long fibers and increase the overall strength of the paper.
2. Selection and Control of Fillers
The quality and amount of fillers are critical in preventing fuzzing and powdering. The ideal fillers should have appropriate crystal shapes (e.g., spindle-shaped), particle size, and specific surface area, which should match the dewatering and forming speed of the fibers. This ensures that the fillers are evenly distributed in the paper, preventing uneven distribution and severe powdering. The control of filler usage also requires balancing the ash content in the paper—too low an ash content increases cost and negatively affects paper flatness, so a balance must be struck.
3. The Role of Additives
Additives, especially cationic starch, play a key role in paper production. Starch improves the strength of the paper, enhancing its surface performance and reducing fuzzing and powdering. Starch not only strengthens the paper but also forms a protective, wear-resistant colloidal film on the paper’s surface, thus increasing surface strength and reducing fiber loss during friction.
However, the use of starch must be moderate. Excessive starch will not continue to improve the paper’s properties and may cause small fibers and fillers to accumulate excessively on the surface of the paper, resulting in differences between the two sides of the paper. Moreover, overuse of starch can lead to an opposing charge between fibers, reducing retention. Therefore, starch should be added as close to the web-forming position as possible, ideally before the pressure screen, to minimize shear loss.
4. Pulp Uniformity and Dewatering Optimization
Fuzzing and powdering problems are closely related to the uniformity of the pulp. During web formation, controlling the ratio of the web speed to consistency is crucial. If the consistency is too low, fibers tend to flocculate, and the dewatering time increases, which negatively affects the uniformity of the paper. To optimize dewatering, gentle dewatering elements such as dewatering blades should be used. The distance and angle of the dewatering elements should be adjusted according to the machine speed and ambient temperature to ensure uniformity and surface quality.
5. Drying Control
The drying process is also critical to the paper’s quality. Rapid drying can cause excessive evaporation of moisture, leading to rough and porous paper surfaces, which weakens the fiber bonding and leads to fuzzing and powdering. Therefore, the drying process must begin with a slow temperature increase to prevent roughness and ensure proper bonding between the fibers. Additionally, the moisture content of the paper must be controlled and stabilized to achieve optimal fiber bonding. This requires a stable drying control system, with each drying cylinder operating under normal, appropriate conditions.
To address fuzzing and powdering issues, it is essential to focus on pulp selection and treatment, especially the effective use of additives. Properly chosen additives (like cationic starch) can significantly improve paper strength and surface properties, thereby reducing fuzzing and powdering. Control over filler quality and usage, fiber optimization, dewatering, drying stability, and proper starch usage are all crucial factors that contribute to solving fuzzing and powdering issues and enhancing overall paper quality.