The functions and applications of sodium carboxymethyl cellulose CMC in the papermaking coating preparation process, the wet end process of the paper machine, the refining process and the surface sizing are as follows:
1. Application of sodium carboxymethyl cellulose CMC in coating preparation
The addition of carboxymethyl cellulose (CMC) to the coating will change the colloidal binding force of the coating due to the adsorption of CMC by calcium carbonate or kaolin in the coating, thereby affecting the degree of flocculation and rheology of the pigment/adhesive particles, so that the coating containing CMC can improve its performance. Water retention and control of coating rheology, the specific effects of CMC in coating applications are as follows:
1.1 Control and adjust the rheology of the coating and the dispersibility of the pigment, and increase the solid content of the coating;
1.2 Enhance the water retention of the coating, improve the rheology of the coating, and improve the quality of the coating;
1.3 Excellent adhesive force, can be used as auxiliary adhesive to reduce the total usage of adhesive;
1.4 Good lubrication effect, protect the scraper from wear and improve the coating efficiency;
1.5 Endow the coating with "pseudoplastic" properties, especially suitable for high-solid coatings and high-speed coating;
1.6 Good film-forming properties, make the coating smoother and brighter, and prevent the occurrence of "orange peel";
1.7 Improve the retention rate of the brightener in the coating, improve the whiteness of the paper, and improve the hue of the paper.
2. Application of sodium carboxymethyl cellulose CMC in wet end of paper machine
After the sodium carboxymethyl cellulose CMC enters the wet end paper, chemical hydration occurs between the carboxymethyl group and the hydroxyl group on the fiber to enhance the bonding force between the fibers, and the bonding force between the fibers is greatly improved. It will be directly reflected in the improvement of almost all physical strength indicators of the paper sheet. The specific effects of CMC in the application of the wet end of the paper machine are as follows:
2.1 Enhance the bonding force between fibers and improve the strength of paper;
2.2 It has the function of sizing in the pulp, giving the paper a certain degree of sizing;
2.3 Good dispersion performance, which is conducive to the formation of paper sheets and improves paper uniformity;
2.4 The sizing agent protector in the pulp promotes the uniform distribution of the sizing agent on the fiber surface;
2.5 Delay the hydrolysis rate of AKD and reduce the possibility of hydrolyzed waste polluting the system;
2.6 Excellent affinity between fine fibers and fillers, improving the one-pass retention of the paper machine and the retention rate of various additives;
2.7 Improve the retention of fillers and fine fibers and reduce the concentration of white water.
3. Application of sodium carboxymethyl cellulose CMC in refining optimization
The addition of carboxymethyl cellulose (CMC) during the refining process of plant fibers can improve the lubricity between fibers, reduce the excessive cutting of fibers during refining, and promote fiber swelling, so that the outer layer of the secondary cell wall can be improved. It is easier to open, the splitting broom is good, and it is easy to beat, and at the same time, it reduces the energy consumption of refining and saves costs. The specific effects of CMC in refining optimization applications are as follows:
3.1 Swell the fiber, promote the splitting and improve the beating degree;
3.2 Form internal fine fibrillation and increase the water retention value of the slurry;
3.3 Improve the lubricity between fibers, avoid excessive cutting, and increase the fiber length;
3.4 Promote the exposure of hydroxyl and carboxyl groups and increase the surface charge of the fiber;
3.5 Under the same beating degree requirement, the energy consumption of refining is greatly reduced.
4. Application of Sodium Carboxymethyl Cellulose CMC in Surface Sizing
CMC, used as a surface sizing agent, has excellent film-forming properties and film transfer performance, and can form good sealing and oil resistance on the surface of paper or cardboard. The material or coating can form a stable and uniform system, so as to obtain a good sizing effect. The specific effects of CMC in surface sizing applications are as follows:
4.1 Good rheological properties, film-forming properties and film transfer properties;
4.2 Improve the paper drawing speed to overcome the paper fluff and powder loss;
4.3 Improve surface strength, air permeability and control curl;
4.4 Improve the surface feel of the paper and improve the printing adaptability;
4.5 It can form good sealing and oil resistance on the surface of paper or cardboard.
5. Others
5.1 Sodium carboxymethyl cellulose CMC is used as an organic coating material for filler modification to enhance the bonding force between fillers and fibers, improve retention rate and optical properties of paper;
5.2 Sodium carboxymethyl cellulose CMC is used as a flocculant in the treatment of papermaking wastewater, reducing the amount of sludge, promoting flocculation and sedimentation, and has high turbidity and COD removal rates;
5.3 Sodium carboxymethyl cellulose CMC is used as a reinforcing agent and surface sizing agent in special paper to ensure the physical indicators of each paper and reduce production costs;
5.4 Sodium carboxymethyl cellulose CMC is used as a wet end enhancer for toilet paper and paper towels, which can improve the evenness of finished paper while ensuring high beating degree;
5.5 Sodium carboxymethyl cellulose CMC is used to improve the evenness of the filter rod paper into paper, enhance the tensile strength, and improve the joint-free rate of the slitting paper;
5.6 Sodium carboxymethyl cellulose CMC can improve the bulk and relative absorbency of the low-quantity tobacco sheet base sheet, and improve the strengt.
