1 lead salt: a type of heat stabilizer used earlier. It has excellent long-term thermal stability, weather resistance and electrical insulation, but it affects the transparency of the product, is toxic, has initial coloring property, is easily sulfided, and has poor compatibility and dispersibility with polyvinyl chloride. Lead salts are non-lubricating and should be used in combination with metal soap lubricants. Commonly used varieties are tribasic lead sulfate and dibasic lead phosphite. Used in the manufacture of opaque PVC sheets, tubes and wire and cable jackets.
2 compound metal salt: a general type of heat stabilizer. It is often bought and sold in the form of a liquid, paste or powder. Commonly used varieties are fatty acid salts of barium-cadmium, barium-calcium-zinc, barium-zinc, calcium-zinc and calcium-magnesium-stann-zinc. Such heat stabilizers are often used in combination with adjuvants to form a compound heat stabilizer suitable for different processing techniques and product application requirements.
3 organotin: These heat stabilizers are mainly used in various soft polyvinyl chloride products that require transparency. Commonly used varieties are maleate esters, thiolates and carboxylates. Among them, di-n-octyltin maleate, S, S'-bis(isooctyl thioglycolate) di-n-octyltin can be used as a stabilizer for food and pharmaceutical packaging materials.
4 special purpose heat stabilizer: refers to some pure compounds with specific effects, such as α-phenyl hydrazine, amino crotonate used in alkaline emulsion polymerized polyvinyl chloride, used in asbestos-filled polyvinyl chloride floor materials Pentaerythritol or dicyandiamide.