The additive should be able to be dispersed in the product stably and uniformly for a long time and exert its effect. Therefore, the additives should have good compatibility with PVC.
For fillers, inorganic pigments and other additives insoluble in PVC, small fineness and good dispersibility are required. In addition, the additives will not promote the degradation of PVC.
It should be durable. It should meet the requirements of low volatility, resistance to water, oil or solvent extraction and good resistance to migration.
　The additives should have good heat resistance, do not decompose, volatilize and sublime at the processing temperature and do not corrode processing equipment and molds.
　Additives should have restrictions on product appearance, odor, pollution, durability, electrical insulation, thermal performance, weather resistance and toxicity.
　At last,the compounding of different species in the same type of additives is very important.