Since the transparent silicone products are transparent, how can they turn yellow, can they still be transparent after yellowing, and what is the cause? Is it oxidation? Normal transparent silicone products will not turn yellow even after being placed for several years, but sometimes in our production, some transparent silicone products that have just come out of the oven turn yellow. Why do transparent silicone products turn yellow? The main problem is In the following aspects:

1. Vulcanizing agent

1. The performance of vulcanizing agent is divided into ordinary type and anti-yellowing property. Its application range has the following two aspects:

2. Ordinary non-yellow vulcanizing agent, used in some non-exposed silicone products that can be used for darker or less color requirements.

3. Anti-yellowing vulcanizing agent is used in products that need to be exposed, lighter and brighter in color, and have high color requirements. The quality of vulcanizing agent is highly correlated with hydrogen-containing silicone oil. Dow Corning hydrogen-containing silicone oil has a hydrogen value of 1.6. Above; the acid value is below 1, the effect is better.

2. Process

When transparent silicone products are formed, the main problems that cause the color of transparent silicone products to turn yellow after molding are:
1. The mold temperature is too high;

2. The vulcanization time is too long;

3. After secondary vulcanization.

3. The quality of the raw material itself is too poor

Sometimes we add an anti-yellowing vulcanizing agent to the rubber compound, but the transparent silicone product still looks yellow after molding. It may be that the anti-yellowing ability of the raw material is too poor. The suggestion for the raw material with poor yellowing resistance is Direct replacement.

Summary: Although silicone products have excellent weather resistance and aging resistance. But sometimes the silicone products that have just come out of the oven still turn yellow. In order to avoid this situation, the curing agent should be selected according to the requirements, the temperature of the mold and the curing time of the product should be strictly controlled in terms of technology, and the yellowing resistance of the raw materials should be paid attention to.