how to Improve heat resistance and weatherability, maintain transparency
Calcium and zinc stabilizers are usually complexed with other additives to achieve the best results, these auxiliaries are called auxiliary stabilizers. So, what these auxiliary stabilizers are? Calcium zinc stabilizer manufacturers Shandong Polymer additives Co., Ltd would like to share with you.
Beta-diketone is one of the most widely used auxiliary stabilizers. It can be replaced with allyl chloride in PVC to stabilize PVC unstable components and form a strong bond of C-C to a more stable structure. It can have a significant synergistic effect with calcium-zinc stabilizers to improve the initial and medium-term colorability of PVC plastic products.
Phosphites are accessory antioxidants and play an important role in the antioxidant system. In PVC formulations, it is generally believed that the phosphite mainly acts as a chelating agent and has no obvious stabilizing effect when used alone. However, when used in combination with a metal soap, it can complex metal chlorides, improve heat resistance and weatherability, and maintain transparency.
3, Polyol compounds
The mechanism of action of polyols as auxiliary stabilizers is similar to that of phosphites and β-diketones, all of which are zinc chloride complexed to retard the degradation process of PVC. Such varieties and β-diketone, epoxy compounds, hydrotalcite used in soft PVC, has an excellent synergy.
Since degradation of PVC follows thermal degradation under anaerobic conditions and thermal oxidation under aerobic conditions, antioxidants can be used as stabilizing components of PVC. Phenolic antioxidants can be complexed with phosphites or thioesters. Phosphite can be used alone, can show a good stabilizing effect, and this antioxidant system both to improve the initial coloring, improve long-term stability of the dual role in formula design can not be ignored.
5, epoxy compounds
Epoxy compounds and calcium zinc stabilizer has a good synergistic effect. The principle is the reaction of epoxy soybean oil with HC1 to generate chlorohydrin, and then with the metal soap to HC1 transfer to the metal soap, re-formed epoxy ring. In addition, epoxidized soybean oil can displace allyl chloride in the presence of a Lewis acid such as a zinc compound to form a stable ether compound.
Calcium and zinc stabilizer composition is one of the efficient auxiliary stabilizer, generally considered to be achieved through the absorption of HCL, its HCL capacity and the thermal stability of a time-linear relationship. The mechanism is divided into two steps: firstly, the anion (such as CO3-) in the interlayer is replaced by Cl- through an exchange reaction, and then the hydroxide portion of the layer is neutralized with HC1 to destroy the layered structure.
Because the composition of PVC heat stabilizers is very important, the choice of reliable PVC heat stabilizer manufacturers is the most critical, because PVC heat stabilizer is an integral part.