CMC (carboxymethyl cellulose) in the papermaking industry is an important additive used to improve the quality and performance of paper. CMC is a water-soluble polymer compound with good viscosity adjustment properties and plays an important role in papermaking.
1. Basic properties of CMC
CMC is a derivative of cellulose, which is made by reacting the hydroxyl part of cellulose with chloroacetic acid. It has excellent water solubility and viscosity adjustment ability. CMC forms a viscous solution after dissolving in water, which makes it very useful in various industrial applications.
2. The role of CMC in the papermaking industry
In the papermaking process, CMC is mainly used as an adhesive, thickener and stabilizer. Its functions include:
2.1 Improve the strength of paper
CMC can effectively enhance the cohesion and tension of paper, and improve the tear resistance and folding resistance of paper. Its mechanism of action is to make paper tougher and more durable by enhancing the bonding force between pulp fibers.
2.2 Improve the gloss and surface smoothness of paper
Adding CMC can improve the surface quality of paper and make the surface of paper smoother. It can effectively fill the gaps on the surface of paper and reduce the roughness of the surface of paper, thereby improving the gloss and printing adaptability of paper.
2.3 Control the viscosity of pulp
During the papermaking process, CMC can effectively control the viscosity of pulp and ensure the fluidity and uniformity of pulp. Appropriate viscosity helps to evenly distribute the pulp, reduce paper defects, and improve production efficiency.
2.4 Improve the water retention of pulp
CMC has a good water retention capacity and can reduce the water loss of pulp during the molding process. This can reduce the shrinkage of paper and the deformation problems that occur during the drying process, thereby improving the stability of paper.
3. Adjustment of CMC viscosity
The viscosity of CMC is a key parameter for its effect in the papermaking process. According to different production requirements, the viscosity of CMC can be adjusted by adjusting its concentration and molecular weight. Specifically:
3.1 Effect of molecular weight
The molecular weight of CMC has a direct effect on its viscosity. CMC with a larger molecular weight usually has a higher viscosity, so high molecular weight CMC is used in applications that require high viscosity. Low molecular weight CMC is suitable for occasions that require lower viscosity.
3.2 Effect of solution concentration
The concentration of CMC solution is also an important factor affecting viscosity. Generally speaking, the higher the concentration of CMC solution, the greater its viscosity. Therefore, in actual production, the solution concentration of CMC needs to be adjusted according to specific requirements to achieve the required viscosity level.
4. Precautions for the use of CMC
When using CMC in the papermaking process, the following points need to be noted:
4.1 Accurate ratio
The amount of CMC added should be adjusted according to the specific requirements of the paper. If too much is added, it may cause the pulp viscosity to be too high and affect the production process; if insufficient, the expected effect may not be achieved.
4.2 Dissolution process control
CMC needs to be dissolved in cold water to avoid degradation during heating. The dissolution process should be fully stirred to ensure that CMC is completely dissolved and avoid agglomeration.
4.3 Effect of pH value
The performance of CMC will be affected by pH value. In paper production, a suitable pH range should be maintained to ensure the best effect of CMC.
CMC plays a vital role in the papermaking industry, and its viscosity adjustment ability directly affects the quality and performance of paper. By properly selecting and using CMC, the strength, gloss, smoothness and production efficiency of paper can be significantly improved. However, in actual application, the concentration and viscosity of CMC need to be precisely adjusted according to specific production requirements to ensure its best effect.
Post time: Aug-13-2024