When the substitution degree of sodium carboxymethyl cellulose (CMC) is equal to 1, the molecular formula is [C6H702(0H)20CH2C00Na]n. Sodium carboxymethyl cellulose is a kind of white or slightly yellow powder, and granular or fibrous solid, which is tasteless, non-toxic, and soluble in water.
The choice of sodium carboxymethyl cellulose as electrolyte in the production of sanitary ceramics is due to its good adhesion, suspension, decoagulation and water retention effects.
The purpose of application is:
① Sodium carboxymethyl cellulose is used as a binder, which can play a good bonding effect. Using sodium carboxymethyl cellulose can increase the strength of the raw glaze, reduce the drying shrinkage of the glaze, make the body and the glaze bond firmly and not easy to fall off, facilitate the process operation, and prevent defects such as glaze rolling and lack of glaze. At the same time, it has a suspending function to suspend the ceramic slurry and prevent precipitation.
②It can play its water-retaining effect, so that the glaze slurry has a certain degree of water retention, and the glaze layer is evenly dried to form a flat and dense glaze surface. After firing, the glaze surface is flat and smooth.
③Using the decoagulation effect of sodium carboxymethyl cellulose (medium and low viscosity) can improve the fluidity of the glaze slurry and facilitate the operation of glaze spraying.
Sodium carboxymethyl cellulose should be stored in a dry environment, which is determined by the hygroscopicity of sodium carboxymethyl cellulose. The equilibrium moisture of sodium carboxymethyl cellulose increases with the increase of air humidity, and decreases with the increase of temperature. The moisture in the product is about 100. According to relevant research reports, the equilibrium moisture of sodium carboxymethyl cellulose can reach 260 when stored at room temperature and an average humidity of 80% to 85%. From this, we can see the cohesiveness of some particles of sodium carboxymethyl cellulose, and the higher the viscosity of CMC, the more obvious the effect.