1. Physical antioxidant
Paraffin is often used as physical anti - aging agent to resist ozone and weather. The paraffin dissolved in rubber during vulcanization cools and gradually migrates to the rubber surface, forming a dense and flexible wax film to isolate ozone in the air and protect it. Compared with the ordinary protective wax, the modified protective wax has many functional groups (such as carboxyl group and hydroxyl group) in its molecular structure. The protective capacity of modified protective wax is 1.5~3 times higher than that of ordinary protective wax. The use of modified paraffin can reduce the amount of anti-ozonant.
2. Chemical antioxidant
Antiaging agents used in synthetic rubber processing are mainly amine and quinoline antiaging agents. Common varieties are 4020,4010 NA and RD. The dosage of these three kinds of anti-aging agent accounts for more than 80% of the current consumption of anti-aging agent in China.
There are A lot of naphthylamine anti-aging agents, such as phenyl - alpha - naphthylamine (anti-aging agent A), 1- phenyl - proterenol-naphthylamine (anti-aging agent D). But because of its toxicity and carcinogenicity, countries began to drastically reduce their production from the 1970s until now banned.
RD has become one of the main anti-aging agents of radial tire compound in China. The active ingredient in the product is 2, 2, 4-trimethyloline-1, 2-hydroquinoline, which has excellent aging resistance performance, so the content of dimer should be increased as much as possible. Anti-aging agent RD has excellent performance of heat-resisting oxygen aging, which has strong inhibition effect on metal ions such as copper, but poor performance of ozone resistance and flexural resistance. It should be used in combination with anti-aging agent AW or p-phenylenediamine (anti-aging agent 4020). Anti-aging agent AW can prevent rubber products from cracking caused by ozone. It is especially suitable for rubber products in dynamic conditions. It can be used with anti-aging agents H, D and 4010 to enhance their efficacy.
In recent years, the development and application of new varieties of rubber anti-aging agent are few, and with the increasingly strict environmental protection requirements, the anti-aging agent gradually develops into high performance and environmental protection direction, and the varieties of rubber anti-aging agent gradually tend to be concentrated. The varieties with the largest dosage in the future are still the anti-aging agent RD and 4020.