What are the reasons for dark marks in silicone rubber products?

Reasons for dark marks in silicone rubber products 
1. the temperature resistance of color paste is too poor. The color of the gel is composed of more than two kinds of color paste. If the temperature resistance of several kinds of color paste is too far apart, it will lead to the high temperature molding, some color paste does not change color, and some color paste because of poor temperature resistance and color, resulting in water ripple phenomenon on the surface of the product after molding. 

2. the forming temperature exceeds the temperature resistance range of the color paste, resulting in inconsistent surface color of silicone rubber products. 

3. Improper discharging mode and mixing of different batches of rubber materials together for forming cause inconsistent surface color of silicone rubber products.