Application of carboxymethyl cellulose CMC in paper industry

Carboxymethyl Cellulose (CMC), as a water-soluble anionic polymer, is widely used in the papermaking industry. Its unique physical and chemical properties make it play a key role in different papermaking links.

1. Pulp enhancer

In the papermaking process, the strength of paper is one of the important indicators for evaluating paper quality. CMC can be used as an efficient pulp enhancer, which can significantly improve the wet strength and dry strength of paper. CMC molecules contain a large number of carboxyl groups, which can form hydrogen bonds with pulp fibers, thereby increasing the binding force between fibers. By adding an appropriate amount of CMC, the physical strength of the paper is enhanced. Especially in the production of low-weight paper and recycled paper, the addition of CMC can significantly improve the strength and texture of the paper.

Another important function of CMC in papermaking is to improve the folding resistance and toughness of paper, which is particularly important for packaging paper, paper bags and other products. Traditional paper is prone to breaking when folded or bent, while CMC significantly increases the durability and tear resistance of paper by improving the bonding force between fibers.

2. Coating agent

In the paper industry, surface coating is one of the key steps to improve the quality and appearance of paper. As an excellent coating agent, CMC is widely used in the paper coating process, especially in the production of high-grade paper, printing paper and coated paper. CMC can effectively improve the uniformity and coating effect of the coating layer.

CMC has good film-forming and adhesion properties. When it is added to the coating liquid, it can evenly cover the paper surface to form a dense coating. The coating not only improves the gloss and smoothness of the paper, but also enhances its printability. In addition, CMC also has good water retention, which can effectively control the evaporation rate of water in the coating liquid and avoid uneven drying during the coating process.

In some specific coating applications, such as the production of food packaging paper, CMC also has the advantage of being non-toxic and harmless, complying with food safety standards, further expanding its application scope in the coating field.

3. Dispersant

In the paper industry, the dispersion of pulp and pigments has a direct impact on the uniformity and quality of paper. As an efficient dispersant, CMC can effectively improve the dispersion of fibers, fillers and pigments in pulp and prevent aggregation between particles.

When CMC is added to pulp or coating liquid, its long-chain molecules can be adsorbed on the surface of fibers or particles, forming a stable protective layer to prevent mutual attraction and aggregation between particles, thereby improving the dispersion effect. This has a significant effect on improving the flatness, uniformity and surface finish of the paper. In addition, CMC can also improve the distribution of fillers in the pulp, giving the paper better light shielding and uniformity, which is particularly important in the production of coated paper and high-grade printing paper.

4. Improvement of water resistance of paper

The water resistance of paper is one of the important factors that determine the service life and functionality of paper. In the production of some special-purpose papers, such as filter paper, food packaging paper and medical paper, the water resistance of the paper is required to be high. CMC has good film-forming properties and can effectively improve the water resistance of paper. By adding CMC to the pulp, the paper will not dissolve or break quickly when exposed to water, thus improving the performance and life of the paper.

CMC can also make the paper perform better when printing and writing by adjusting the wetting properties of the paper, preventing ink from spreading and improving the printing effect.

5. Other applications

In addition to the above-mentioned main functions, CMC also has good emulsification properties, thickening effect and stability, making it widely used in other aspects of the papermaking process. For example, CMC can be used as a filter aid to help improve the dehydration efficiency of pulp and shorten papermaking time; as an emulsifier, it can help disperse and stabilize some special additives or chemicals to ensure the smooth progress of the papermaking process.

Carboxymethylcellulose (CMC) plays an integral role in the paper industry. It can not only improve the physical strength, coating effect and dispersion of paper, but also improve the water resistance and other properties of paper. With the continuous advancement of papermaking technology, CMC will have wider application prospects in the future papermaking industry. Reasonable selection and use of CMC can not only improve the quality of paper, but also reduce production costs and improve the market competitiveness of enterprises.