Why does transparent silicone rubber product turn yellow?

In order to avoid the yellowing of silicone rubber products, the vulcanizing agent shall be selected according to the requirements. In terms of process, the temperature of the mold and the vulcanization time of the product shall be strictly controlled. In terms of raw materials, special anti yellowing raw materials shall be selected.

The transparent silicone rubber products will not turn yellow after being put in normal use for several years, but sometimes during production, some transparent silicone rubber products that have just been baked look yellow and seem to have changed color. Why does transparent silicone rubber product turn yellow?

1、 Vulcanizing agent

Vulcanizing agent performance can be divided into ordinary type and yellowing resistance

1. common non yellowing curing agent is applied to some non exposed silicone rubber products with dark color or low color requirements

2. anti yellowing vulcanizing agent shall be used for products that need to be exposed, have light and bright colors, and have high color requirements

2、 Process

During the forming of transparent silicone rubber products, poor production process control leads to the yellow color of transparent silicone rubber products after forming. The main problems are:

1. mold temperature is too high

2. too long vulcanization time

3. after secondary sulfur addition

3、 Poor quality of raw materials

Sometimes we add anti yellowing vulcanizing agent to the compound, but the transparent silicone rubber product still looks yellow after molding. It may be that the anti yellowing ability of the raw materials is too poor. For the raw materials with poor anti yellowing ability, it is recommended to directly refuel.

Summary:

Although silicone products have excellent weather resistance and aging resistance. But sometimes the newly baked silicone rubber products are yellow. In order to avoid this situation, the vulcanizing agent shall be selected according to the requirements. In terms of process, the temperature of the mold and the vulcanization time of the product shall be strictly controlled. In terms of raw materials, special anti yellowing raw materials shall be selected