Antioxidants are a class of chemical substances, when only a small amount of them in the polymer system, can delay or inhibit the process of polymer oxidation, so as to prevent the aging of the polymer and prolong its service life, also known as "aging agents".
For engineering plastics processing, antioxidants can prevent the thermal oxidation degradation of some polymers (such as ABS, etc.) during processing, so that the forming process can proceed smoothly. The amount of antioxidant added - generally only 0.1-0.5.
The ideal antioxidant should have the following conditions:
Should have high antioxidant capacity;
(2) good compatibility with resin, not precipitated;
(3) good processing performance, in the processing temperature of the polymer does not volatilize, do not decompose;
(4) good extraction resistance, insoluble in water and oil;
The color itself is colorless or light, which does not pollute the product;
Non-toxic or low-toxic;
The price is low.
In fact, any kind of antioxidant can not fully meet these conditions, therefore, in actual use, often according to the type of engineering plastics, use and processing methods, the use of the length of a variety of additives, with the use, in order to produce synergistic effect.