Application of calcium stearate in polymer materials
The use of calcium stearate in the production, processing and modification of polymers was introduced. Calcium stearate is used in PVC heat stabilizers and lubricants. Calcium stearate is used for β-crystalline nucleating agents and halogen absorbers of polypropylene. Calcium stearate is both a stabilizer and vulcanization speed inhibitor for halobutyl rubber products and a dispersant and lubricant in the production of halobutyl rubber.
Calcium stearate is a metal soap surfactant. Due to its simple preparation method and low cost, calcium stearate is widely used in paints, plain papers, and paper coating aids. In addition, calcium stearate is also used in pencil core lubrication and construction waterproofing. In the field of polymer materials processing, calcium stearate is a commonly used mold release agent. In fact, in addition to its use as a mold release agent, calcium stearate has a very wide range of applications in the field of polymer materials due to its characteristics of being non-toxic, environmentally friendly, and weakly alkaline.
Polyvinyl chloride (PVC) In the course of processing, PVC is easily broken and crosslinked due to dechlorination, which makes the color of the material deeper and the performance deteriorates. Various methods can be used to study the effect of calcium stearate on the properties of PVC materials, such as studying the color change with yellow index and refractometer, and using FTIR to study the generation of carbonyl, with relative molecular masses and The gel content studies the cross-linking and degradation of the material. The study found that although the temperature does not affect the dechlorination of the material, the rate of dechlorination is greatly affected by temperature. During the degradation of the material,
Linkage plays a leading role. The effect of calcium stearate on the pyrolysis performance of PVC was investigated. The results showed that the calcium stearate had a significant retarding effect on the pyrolysis and dechlorination of PVC, and the maximum dechlorination rate was significantly reduced. This shows that the presence of calcium stearate on PVC Dechlorination has a significant inhibitory effect
The reason why calcium stearate inhibits dechlorination of PVC is that calcium stearate can absorb free radicals formed during the pyrolysis process, and calcium stearate can also react with HCl generated during the dechlorination process to reduce the dechlorination rate.
In practical applications, calcium stearate alone is rarely used as a heat stabilizer. The calcium stearate-zinc stearate complex has a significant synergistic effect on the stabilization of PVC. After the introduction of calcium stearate-zinc stearate complex, the thermal stability of PVC can be significantly improved. The calcium stearate-strontium stearate complex system also has a good thermal stability effect on PVC, and it works better when used with organic tin. The test results show that the use of a rare earth stearic acid salt-zinc stearate-calcium stearate as a PVC stabilizer can significantly improve the thermal stability, processability, and mechanical strength of the PVC resin.