Share the solution to the yellowing of the Automotive Wiring Harness Protection Sleeve

The Automotive Wiring Harness Protection Sleeve that is in contact with food turned yellow after being exposed to a high temperature of 200°C for 4 hours. What is going on?

Using silicone high yellowing resistance vulcanizing agent C-15 may solve this problem. Generally, food-grade products have this requirement. To prevent yellowing due to secondary sulfur addition, anti-yellowing catalyst + anti-yellowing agent must be used. Both are indispensable, but these two substances will make the hydraulic production a little sticky, so it is necessary Things to pay attention to. Add 2-3 parts per thousand of hydrogen-containing silicone oil according to the amount of silicone. High hydrogen-containing silicone oil can solve the yellowing problem, but the product may be a bit brittle and sticky. You can spray a layer of silicone oil on the mold to solve the demoulding problem. Problem, other than that, the only solution is to use platinum to build the bridge.
It is certainly a good idea to use anti-yellowing agents and anti-yellowing vulcanizing agents. However, you also need to pay attention to whether the Braided Sleeve you are using is ideal. You cannot add too much internal release agent, zinc stearate, so you need to communicate with the supplier to see if there is already hydrogen-containing silicone oil in it to provide anti-yellowing. The powder is very important for the effect. If the iron content in it is too high, it will definitely turn yellow.
You can test it and compare the vulcanizing agent with ordinary vulcanizing agent (without anti-yellowing agent) and the vulcanizing agent with anti-yellowing agent. Be careful not to add zinc stearate type internal release agent. If it still doesn't work, it is recommended that you switch to other rubber compounds or use platinum vulcanizing agent. If there is sulfur or sulfur carriers in the environment (such as sulfur vulcanized products that have just been baked in the oven), it will also cause yellowing of the Braided Sleeve.