Why can transparent silica gel pad become yellow?

Transparent silica gel pad normally put a few years will not turn yellow, but sometimes in the production, some of the transparent silica gel products just out of the oven look yellow, as if changed color. Transparent silicone pad why yellow?

One. Curing agent

1 vulcanizing agent properties are divided into common type and yellow resistance. Its application scope has the following two aspects:

2 ordinary type not yellow vulcanizing agent, applied to some can be used for dark color or color requirements are not high non-exposed silica gel products.

3. Anti-yellow vulcanizing agent is applied to products that need to be exposed, lighter and brighter in color, and have higher requirements for color.

Ii. Technology

Transparent silica gel pad in molding, resulting in transparent silica gel pad after molding color yellow main problems are:

1. The mold temperature is too high

2. Vulcanization time is too long;

3. After adding sulfur twice;

4. The raw material itself is of poor quality

Sometimes we add anti-yellow vulcanizing agent in the rubber, but the transparent silica gel product still looks yellow after molding, it may be that the yellow resistance of the raw material is too poor, the raw material advice for the poor yellow resistance of the raw material is direct refuelling.

Conclusion: Although silica gel products have excellent weather resistance and aging resistance. But there are still times when freshly baked silicone products are yellow. In order to avoid this situation, according to the requirements of the choice of curing agent, process to strictly control the mold temperature and curing time of the product, the raw material should pay attention to the yellow resistance of raw materials.