Rubber tire antioxidant selection criteria

1、Discoloration and staining
In general, phenolic antioxidants are usually non-discoloring, while amine antioxidants are discoloring. For rubber elastomers containing carbon black, more effective are amine antioxidants, discoloration is not important at this time.
Picture

2、Volatility
As the molecular weight of the antioxidant increases, the volatility will decrease, while a hindered phenol of the same molecular weight has a higher volatility than a hindered amine. Therefore, it is crucial to add the correct antioxidant during the mixing process.

3、Solubility
Antioxidants with low solubility will result in a mottled and blemished surface of the rubber, even if the protection is excellent, and should be chosen carefully.
Antioxidants, especially those resistant to ozone aging, need to control their effective solubility. Soluble ones must be selected, which must be able to migrate to the surface of the material when added at levels up to 2.0%, yet not be soluble in water or other solvents (e.g., hydraulic fluids) in order to prevent extraction of the antioxidant from the rubber.

4, chemical stability
The antioxidant should be durably stable to heat, light, oxygen and solvents.

5、Parts
Most antioxidants, there is an optimal amount to add, after exceeding, the solubility becomes the biggest limiting factor. P-phenylenediamine antioxidant content of 0.5% to 1.0% can provide good protection, anti-ozone aging antioxidant add 2.0% to 5.0% of the amount, the protective effect is very good. If the p-phenylenediamine antioxidant is added 5.0%, the surface of the rubber is prone to mottling and defects.

6、HSE requirements
In order to facilitate the operation, to avoid dust and inhalation, anti-degradation agent in the process of adding and refining should be dust-free.

7、Test and analysis
After the rubber products and tires are used, the content of antidegradant will gradually decrease because of decomposition, volatilization, dissolution, etc. It can be analyzed and detected by instrumental means such as gas chromatography-mass spectrometry, thin-layer chromatography, high-performance liquid chromatography and so on.