Stearate is one of the main types of PVC heat stabilizers. It can be used as a lubricant for PVC heat stabilizers and is widely used in various soft and hard products. They can effectively combine with HCL degraded during processing, thereby slowing down the further degradation of PVC and stabilizing the appearance and physical properties of PVC. Such stearates usually include: zinc, calcium stearate ,, barium, magnesium. Lead, cadmium salts, etc.
Among them:
Zinc stearate: It is a white powder, insoluble in water, soluble in hot ethanol, benzene, toluene, turpentine and other organic solvents ; When encountering acid, it decomposes into stearic acid and corresponding salts; It is fire hazard under dry conditions, with an auto-ignition point of 900°C; It is hygroscopic. In terms of thermal stability of PVC: it is non-toxic and transparent. Large dosages can easily cause “zinc burning” and make the edges of the product uneven. It is often used together with calcium, barium, etc.
Calcium stearate: white powder, insoluble in water, cold ethanol and ether, soluble in hot benzene, benzene and turpentine and other organic solvents, slightly soluble in hot ethanol and ether. It decomposes slowly when heated to 400°C and is flammable. It decomposes into stearic acid and corresponding calcium salts when exposed to strong acid and is hygroscopic. In terms of thermal stability of PVC: good processing performance, low thermal stability, and non-toxic.
Barium stearate: white or slightly yellow amorphous powder, melting point >225℃, stimulating effect on the central nervous system, soluble in hot ethanol, benzene, toluene and other non-polar solvents, insoluble in water and ethanol. It is heated and dissolved in an organic solvent and becomes a gel when cooled, and is water-absorbent in the air. No sulfide contamination. When encountering strong acid, it decomposes into stearic acid and the corresponding barium salt. In terms of PVC thermal stability: good long-term thermal stability and transparent, but partially limited by certain environmental protection directives.
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