The influence of pH and additives on pulping
The pH value of the pulping process mainly depends on the quality of the water used and the washing condition of the pulp. In actual production, the pH value is generally not adjusted. If pulping is carried out under acidic conditions, the strength of the paper is low, it is prone to cracking, which is unfavorable for pulping, and the acidic pulp will cause certain corrosion to the conveying equipment. Therefore, when conveying such pulp, it is particularly important to select a polyester plain woven mesh belt with excellent acid resistance. This mesh belt not only has stable material and is resistant to acid corrosion, but also has good air permeability and is not prone to sticking to the pulp. It can effectively avoid pulp waste and ensure smooth and efficient conveying in the process, and is suitable for the production requirements of acidic pulping.
When pulping under alkaline conditions, the tensile strength of the paper is improved. This is because under alkaline conditions, the low-molecular parts of cellulose are prone to peeling reactions and are removed, making water easily diffuse into the fibers and promoting the fiber swelling effect, reducing the cohesion of the fibers, and increasing the flexibility of the fibers. Thus, the damage to the fibers by the mechanical action of the pulping machine is reduced. After fiber swelling, the fibers are more easily fibrillated, and the binding force between the fibers will also increase, thereby improving the strength and toughness of the paper. This characteristic is particularly obvious in the pulping of common pulp materials such as broadleaf wood pulp and straw pulp.
In addition, adding NaOH during the pulping process will cause the residual lignin in the pulp to dissolve, reducing the obstruction of lignin on the fiber bonding, which may also be beneficial for improving the strength of the paper. At the same time, the alkaline environment and the presence of NaOH will enhance the corrosiveness of the pulp. The Polyester Plain Woven Mesh Belt has excellent alkali resistance and chemical stability, and can be used for a long time to meet the transportation requirements of such corrosive pulps. It is not prone to aging or damage, which can effectively extend the service life of the equipment, reduce the frequency of production shutdown and maintenance, and further improve the overall efficiency of the pulping process.
Some people believe that the straw pulp can achieve good burst strength and tear length under a pH of 9, and the cotton pulp has the maximum paper strength when the pH is 8.5. However, others think that the pH range of 7 to 7.5 is not conducive to the strength of the paper made from the straw pulp. This difference is mainly related to the type of pulp, the purity of the fibers, and the control of the refining degree. In actual production, it is necessary to flexibly adjust the pH range based on the characteristics of the pulp and the quality requirements of the finished paper, while also combining with the stable conveying of Polyester Plain Woven Mesh Belt, to balance production efficiency and product quality, and avoid affecting the refining effect due to inappropriate pH or conveying problems.
