PVC heat stabilizers are mainly used in PVC and other chlorinated polymers. It is found that PVC plastic can only be processed and formed at above 160 °C, but it begins to decompose at 120 ~ 130 °C, releasing HCL gas. If HCL is not suppressed, the decomposition will be further intensified This problem used to be a major problem in the development and application of PVC plastics.
It is found that if a small amount of impurities such as lead salt, metal soap, phenol and aromatic amine is contained in PVC plastics, the processing and application will not be affected, and the thermal decomposition will be retarded to a certain extent. The above problems were solved, which promoted the establishment and development of the Research Field of heat stabilizer.
Broadly speaking, any additive that improves the thermal stability of a polymer is called a heat stabilizer. Most of the world's PVC stabilizers are used in polyvinyl chloride because of the poor thermal stability of polyvinyl chloride. Thus, PVC stabilizers generally refer to heat stabilizers of polyvinyl chloride and its copolymers.
They can be classified as basic lead salts, metallic soaps, Organotin, Epoxide, phosphite esters, polyols, etc. . PVC stabilizer can be divided into main stabilizer and auxiliary stabilizer according to the effect size. The Auxiliary stabilizer itself has little or no heat stabilization, but it has a synergistic effect with the main stabilizer, which is generally a heat stabilizer containing metals. Pure organic compounds such as Epoxide, phosphite, and polyols are generally used as co stabilizers.
Because many kinds of PVC heat stabilizers are used at the same time in order to achieve good stability of polyvinyl chloride, some commercial PVC stabilizers are compounded by many components and become compound stabilizers, such as ba-cd stabilizer, ba-zn stabilizer, etc. These composite stabilizers are usually polyvinyl chloride with additives such as lubricants required for machining operations. There are many varieties of composite stabilizers, available in powder, paste, liquid, three forms.
Heat stabilizers can be classified into the following categories:
1. Composite Lead Salt Stabilizer
OBS WITH ORGANIC BASE STABILIZER
3. ORGANOTIN STABILIZERS
4. Liquid Composite Stabilizer
5. CALCIUM ZINC COMPLEX STABILIZER
6. Barium ZINC COMPLEX STABILIZER
7. POTASSIUM ZINC COMPLEX STABILIZER