Antioxidants are additives that inhibit or delay the degradation of polymers due to the action of oxygen or ozone in the atmosphere. They are among the most widely used additives in rubber.
The classification of antioxidants used in rubber tires is as follows:
1. Aromatic amine antioxidants:
Aromatic amine antioxidants, also known as rubber antioxidants, are the main antioxidants used in rubber tire processing. Important aromatic amine antioxidants include compounds such as diphenylamine, p-phenylenediamine, and dihydroquinoline and their derivatives or polymers, which can be used in natural rubber, styrene-butadiene rubber, and chloroprene rubber.
Performance characteristics of aromatic amine antioxidants: significant antioxidant effect, low price, and ability to discolor products (limiting their application in light-colored and white products.)
2. Hindered phenolic antioxidants:
Hindered phenolic antioxidants are the main antioxidants for rubber tires. They are divided into monophenols, bisphenols, and polyphenols according to their molecular structure. Phenol, nitrogen heterocyclic polyphenols and other varieties. In the processing and use of rubber tires, monophenol and bisphenol antioxidants are mainly used, such as BHT, 2246, bisphenol A and other products.
Performance characteristics of hindered phenolic antioxidants (monophenol, bisphenol): significant thermal oxidation effect, no contamination of products, high volatility and migration, and easy coloration.
3. Sulfites and sulfur-containing antioxidants:
The auxiliary antioxidants used in rubber tire processing are mainly sulfites and sulfur-containing antioxidants. Sulfur-containing antioxidants.
Performance characteristics of sulfites and sulfur-containing antioxidants: they can decompose peroxides, chelate metals and Lewis acids, have a good synergistic effect with other antioxidants, and at the same time impart heat to rubber tires. Stability and light stability, passivation of harmful metals, slowing down polymerization of polymers.
4. Compound antioxidants:
Different types of primary and auxiliary antioxidants or antioxidants of the same type with different molecular structures have different functions and application effects. Long composite antioxidants are made up of two (or more) different types or different varieties of the same type of antioxidants. They can be used to offset weaknesses in rubber tire processing to achieve the best resistance with the minimum addition amount and the lowest cost. Thermal oxygen aging effect. For example, antioxidant b215 is a compound of main antioxidant 1010 and auxiliary antioxidant 168.
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