CMC used in the coating of paint
Sodium carboxymethyl cellulose have been widely applied to the pigment coated paper and board, including bar coating, air knife coating, blade coating, film coating or the like coating metering ingredients. CMC role for the control, regulation coating rheology, water retention, the coating operation of the job as well as other supporting role, etc. are very important.
A, CMC in the pigment coating of functions:
1, to improve the stability of the coating;
2, regulate water retention paint;
3, adjusting the viscosity of the coating;
4, high adhesive efficiency, CMC itself is a binder;
5, a dispersant, a good dispersion, a more uniform distribution of the coating;
6, brighteners carriers, optical brighteners have a high retention rate;
7, scraper lubricant.
After extensive use of a blade coater, the coater increasing vehicle speed, stability and runnability requirements paint also increased, CMC may improve the chemical and mechanical stability, both of which will affect the operation of the coating machine situation.
Paint water retention usually refers to a coating applied to the paper in which the ability to maintain the free water without escape to go. Paint water retention is a crucial indicator of the production of high-quality coated paper and paperboard, is the key to improving the efficiency and quality of the coating. Paper is a porous absorbent material, so that the paper will inhale some water from the adhesive coating contains solubility, the higher water retention paint, it is less absorbent paper, adhesive migration less: If too much water retention low, there will be a series of problems: the coating streak, adhesive migration, bad paint rheology control, increasing the frequency of sheet breaks.
Coating contains CMC presented pseudoplastic (shear thinning), which is suitable for high-speed blade coating requirements, have excellent water retention in the coating machine with good performance. And the rheology of latex is usually not affected by the kind and amount of performance. When the CMC of the variety and amount of changes that can control and adjust the viscosity of the paint.
Two, CMC acting on the pigment coated
1, increasing the strength of the paper, to improve the wear resistance of the paper, reduce linting tendency of the printing process;
2, protective sizing agent (rosin, AKD, etc.), so that the sizing agent can be very uniformly and effectively distributed in the fiber;
3, has the effect of retention agent, and fibers and fillers have affinity interaction;
4, to improve the air permeability of the paper and control the curl;
5, to increase brightness and gloss of the paper;
6, to improve retention of oil and ink.