CMC For Paper Making

Application Background of Paper-Grade CMC

In modern society, an increasing number of documents are digitized, but paper still plays an irreplaceable role in information recording. Sodium carboxymethyl cellulose (CMC) is an excellent dispersant and binder, as well as a water-retaining agent capable of emulsification. Due to these properties, it is widely used in the paper industry.

A Brief Analysis of CMC

Carboxymethyl cellulose (CMC) is a water-soluble anionic surfactant with certain dispersing ability. It optimizes fiber distribution in the network, promoting uniform fiber weaving. When dissolved in water, it forms a transparent, viscous solution. When added to pulp, it coats the fibers. During paper forming, drying, and dehydration, the presence of hydroxyl and carboxymethyl groups causes strong hydrogen bonds between molecules. This bridging effect between fibers forms numerous hydrogen bonds, enhancing the binding force and thus improving paper strength.

Electrostatic adsorption is the primary force for wet-end chemical retention. The presence of carboxyl groups on the fiber surface gives the fiber a certain negative charge, providing important adhesion sites for the adsorption of wet-end chemicals. Carboxymethyl cellulose has strong affinity, and its combination with suitable cationic auxiliaries will have a synergistic effect.

Applications of Paper Grade CMC

1. In the pulp preparation stage, paper grade sodium carboxymethyl cellulose is added to the pulp as an additive. It can increase the viscosity of the pulp and improve the dispersion of fibers. This helps reduce fiber flocculation and makes the pulp more uniform. Its water-retention properties prevent premature water loss and maintain appropriate fluidity.
2. In the application of reinforcing agents, CMC (Paper Making Grade) can improve the physical strength of paper. It achieves this by increasing the bonding area and bonding strength between fibers. Adding an appropriate amount of paper grade sodium carboxymethyl cellulose can improve the tensile strength and bursting strength of paper. This reinforcing effect is particularly noticeable for paper using recycled fibers.
3. As a surface sizing agent, CMC Paper Grade can improve the surface properties of paper. It forms a thin film on the paper surface, which can improve the surface strength of the paper and reduce linting and dusting. It can also improve the printability of paper, making the printed pattern clearer.
4. In retention and filtration aid applications, CMC for paper industry can help retain fine fibers and fillers. Through bridging and charge neutralization, it makes it easier for fine particles to remain in the paper sheet. This not only improves raw material utilization but also enhances the white water system. It also accelerates wet-end dewatering, increasing the efficiency of the paper machine.

Advantages of Papermaking Grade CMC

After addition, paper strength can increase by 40-50%, and flexibility can increase by 4-5 times. After use, the paper's fiber pores are sealed by the adhesive film, reducing the paper's absorption of moisture from the air and preventing moisture evaporation when the air is dry. This prevents paper from curling or becoming brittle, improves surface strength and smoothness, enhances ink absorption, and improves overall quality. Papermaking grade CMC is used in paper and paperboard coatings to improve water retention, prevent the migration of water-soluble binders, improve rheology, and enhance pigment leveling.