We all encounter the discoloration of some products in our daily work. The latex tube will turn white when stored at room temperature, and the silicone tube will turn yellow at high temperature. The existing problem is that the transparent silicone tube that needs to be in contact with food turns yellow after being placed at a high temperature of 200°C for 4 hours. What is going on?
With silica gel high anti-yellowing vulcanizer C-15, this problem may be solved. General food-grade products have this requirement. To prevent secondary vulcanization and yellowing, be sure to use an anti-yellowing catalyst + an anti-yellowing agent. Both are indispensable, but these two things will make it a little sticky during oil pressure production. Things to pay attention to. Add 2-3/1000% of hydrogen-containing silicone oil according to the amount of silicone. High hydrogen-containing silicone oil can solve the problem of yellowing, but the product may be a little brittle and sticky. You can spray a layer of silicone oil on the mold to solve the mold release. The problem, other than that, the only way to bridge it is to use platinum.
Silicone tube manufacturers analyze for you: of course, it is a good idea to use anti-yellowing agent and anti-yellowing vulcanizing agent. However, it is also necessary to pay attention to whether the silicone tube you use is ideal, and you cannot add too much internal mold 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 effect of powder is very important. If the iron content in it is too high, it will turn yellow.
You can try it out and compare it with ordinary vulcanizing agent (without anti-yellowing agent) and vulcanizing agent with anti-yellowing agent. Be careful not to add zinc stearate internal mold release agent. If it still does not work, it is recommended that you switch to another compound or use a platinum vulcanizing agent. If there is sulfur or sulfur carrier in the environment (such as products that have just been baked with sulfur vulcanization in the oven), it will also cause the silicone tube to turn yellow.