Calcium stearate white powder, insoluble in water, soluble in organic solvents such as hot benzene, benzene and turpentine, slightly soluble in hot ethanol and ##. When heated to 400 ° C, it decomposes slowly, is flammable, decomposes into stearic acid and corresponding calcium salts in case of strong acid, and is hygroscopic. It is used as a non-toxic heat stabilizer for PVC and has excellent lubricity.
How effective is calcium stearate thermal stabilization?
Although the heat stabilization effect is not as good as barium stearate, lead stearate, tin stearate and cadmium stearate. However, it is inexpensive, less toxic, and has good processing performance. Combined with zinc soap and epoxy compounds, it has a synergistic effect and can improve thermal stability.
It is often used in food packaging films, medical equipment and other soft products that require non-toxicity. Used with salt-based lead salts and lead soaps in hard products, it can improve the gelatinization rate. Used in polyethylene and polypropylene to eliminate the adverse effects of residual catalysts on resin color and stability.
It should be noted that the disadvantage of calcium stearate is that it has initial colorability, and when the heating time above 100 ° C is longer, it will make the white PVC plastic become slightly reddish, especially in the presence of titanium dioxide in the formula, the coloring is particularly serious. At this time, if 0.06~ 0.12% na2co3 or 0.09~ 0.19nahco3 is added, this disadvantage can be overcome, but because these substances are too alkaline, they are not used in practice.
![Calcium stearate has four production methods[fig]](data:image/gif;base64,R0lGODlhAQABAIAAAP///wAAACwAAAAAAQABAAACAkQBADs=)