Principles antioxidant use

The selection of antioxidants should be based on the type and model of plastic materials, processing equipment and process conditions, the variety and amount of other chemical additives, the product's use of the environment and the period of time and other factors to determine the antioxidant varieties. Selection of antioxidants for industrial use should be based on the following principles.

1, compatibility

Plastic polymer polymers are generally non-polar, while the antioxidant molecules have different degrees of polarity, the two are poorly compatible, usually at high temperatures in the antioxidant and polymer melt combination, polymer curing antioxidant molecules in the polymer molecules between the tolerance.

2、Migration

Plastic products oxidation reaction mainly occurs on the surface of the product, which requires antioxidants to continuously migrate from the internal plastic products to the surface of the product and play a role. However, if the migration speed to the surface of the product is too fast, the migration amount is too large, the antioxidant should be volatilized to the surface of the product in the environment, or diffuse to the surface of the product in contact with other media and loss, this loss is in fact unavoidable, the design of the formula should be taken into account.

3、Stability

Antioxidants in plastic materials should remain stable, in the use of the environment and high-temperature processing volatilization loss is small, does not change color or color, does not decompose, does not occur with other additives unfavorable chemical reaction, does not corrode machinery and equipment, is not easy to be extracted from the surface of the products of other substances.

4、Processability

Antioxidant melting point and resin melting range if the difference is large, will produce antioxidant bias flow or hold screw phenomenon. If the melting point of antioxidant is lower than the processing temperature of more than 100 ℃, the antioxidant should be made into a certain concentration of masterbatch before mixing with resin to process the products, in order to avoid uneven distribution of antioxidant in the products and decrease in the processing yield due to bias flow.

5、Environmental and hygienic

Antioxidant should be non-toxic or low toxicity, no dust or low dust, no harmful effect on human body in the processing and manufacturing and use of plastic products, no harm to animals and plants, and no pollution to air, soil and water system.