Since the protective effect of each antioxidant is limited, and the aging of rubber products in actual use is the result of multiple factors, the following points should be noted when selecting antioxidants:
(1) Due to the different characteristics of each antioxidant, and the different aging properties of different rubber compound formulations, an antioxidant most effective for one type of rubber may be ineffective or even harmful to another. Therefore, the selection of antioxidants must be based on a comprehensive consideration of the aging properties of various rubber compounds, anti-aging requirements, and the characteristics of various antioxidants.
(2) When one antioxidant is insufficient to meet the requirements, two or more antioxidants should be used in combination to achieve a synergistic effect and ensure the anti-aging effect.
(3) Some antioxidants have a coloring effect and cause contamination of rubber. Generally speaking, phenolic antioxidants have poor protective effects but do not cause contamination or cause very little contamination. Amine antioxidants, which have higher protective effects, will cause severe contamination and discoloration of rubber. These contradictions should be considered comprehensively when selecting antioxidants.
(4) The amount of antioxidant used should not exceed its solubility in rubber to prevent blooming and contamination of the rubber surface.
(5) Amine antioxidants have an adverse effect on rubber scorching; phenolic antioxidants can delay vulcanization, and care should be taken when selecting them.
