Why do silicone rubber products have dark marks?

In the manufacturing process of silicone products, sometimes the color of the viscera and the water ripple effect will appear in the manufactured product. This effect is collectively called “dark mark”, which is an undesirable phenomenon.

1. The temperature resistance of the color paste is very little, resulting in water ripple effect on the surface of silicone rubber products. The color of the rubber compound that causes dark marks during textile molding is formed by the combination of two different color pastes. If the temperature resistance performance of several color pastes is far apart, it will cause some color pastes to fade when forming at low temperature. No fading, so some color pastes fade due to little heat resistance, resulting in water ripples on the surface after the product is formed.

2. The color of the temperature-resistant area where the forming concentration is lower than that of the color paste fades, resulting in a different color tone on the surface of the silicone rubber product.

3. The discharge method is not correct and different types of rubber materials are mixed together to form different surface colors of silicone rubber products.