Sometimes, when rubber compounds are used to make transparent or semi-transparent products, they may turn yellow. Especially after secondary vulcanization, the yellowing phenomenon becomes more obvious.
One of the reasons for yellowing is that silica may contain impurities and turn yellow due to oxidation at high temperatures. The second is that the residual trimethylamine in the raw rubber is oxidized into colored genes. Thirdly, the decomposition of peroxides may also produce yellow substances.
To overcome yellowing, it is necessary to pay attention to choosing silica varieties that are less prone to yellowing, add hydrogen-containing silicone oil and other anti-yellowing agents to the compound rubber formula, and at the same time, pay attention to improving the quality of raw rubber. The low-molecular-weight substances removed should not be reused repeatedly. Finally, anti-yellowing vulcanizing agents can also be used to achieve the anti-yellowing effect