Why The Silicone Will Turn Yellow Over Time

Silicone will turn yellow over time. There are many reasons for this phenomenon, mainly including the following aspects:

1. Raw material problems
Color glue problem: Color glue is the main material for adjusting the color of silicone products. It is composed of color powder, silicone oil, dispersant and silicone raw materials. If the dispersant and silicone oil formula fails to reach a certain ratio, or there is a problem in the raw materials that causes the silicone raw materials to be mixed unevenly when adding color glue, it may cause the silicone product to fade. In addition, the coloring effect of the color powder is not good, and the color dispersion is too large and incompatible with the silicone material, which is also a cause of the fading problem.
Silicone resin raw materials: If the proportion of silicone resin raw materials such as vinyl resin exceeds the normal range (usually below 1%), it may also cause the silicone product to turn yellow.
2. Processing process problems
Catalyst influence: Catalyst plays a key role in the production of silicone products. It not only affects the product's sulfur addition effect, odor and material dispersibility, but also has an important impact on anti-yellowing and fading. Different brands of catalyst adjustment formulas have different levels of emphasis on anti-yellowing and fading. Therefore, when adjusting other properties, it may not be possible to control several properties to the best state at the same time.
Improper process: In the production process of silicone products, if the process is improper, such as the vulcanization temperature is too high, the time is too long, etc., the silicone products will also turn yellow.
3. Use environment and conditions
Environmental factors: The use environment and use conditions of silicone products will also affect their color. For example, long-term use in high temperature, oil, strong light and other environments may accelerate the yellowing and fading process of the product. Pollutants in the air, such as harmful gases, dust, etc., may also affect the color of silicone to a certain extent.
Oxidation reaction: The silicon-oxygen bonds in silicone may be affected by oxygen and undergo oxidation reactions, causing the silicone to turn yellow.
Ultraviolet exposure: Long-term exposure to ultraviolet rays, such as direct sunlight, will cause changes in the molecular structure of silicone, causing it to turn yellow.
Moisture influence: Long-term exposure to a humid environment may cause the absorption of moisture on the surface of silicone, which may accelerate the yellowing process of silicone.
4. Decomposition of additives
Certain additives added to silicone, such as antioxidants, colorants, etc., may decompose during long-term use, causing silicone color changes.
5. Influence of impurities
Impurities that may remain during the production of silicone, such as metal ions, organic impurities, etc., may promote oxidation and discoloration of silicone under certain conditions.