Why do silicone rubber products turn yellow after being used for a long time?
Why do silicone rubber products turn yellow after being used for a long time?
The yellowing and fading of silicone rubber products used in daily life has become a problem for many of our consumers. They believe that silicone rubber materials will yellow and fade, such as cheap silicone rubber mobile phone cases and sports bracelets wearing silicone rubber accessories. However, from a professional point of view, silicone rubber products do not have such fading and yellowing phenomena. This is only caused by different product and material manufacturers. The more outrageous fading or color overflow, the more unacceptable it is. So what? Yes? Cause of color problem?
In general, we can understand the quality of the color of silicone rubber products from two aspects. Generally speaking, this phenomenon does not occur in all products. Such problems mainly come from materials. If the material cannot meet the performance, the products produced by silicone rubber processing manufacturers will naturally not meet the performance.
1. Color glue problem
Color glue is the main material for color matching of silicone rubber products. The main materials are composed of carbon powder, silicone oil, dispersant and silicone rubber raw materials. The main reason for the discoloration of silicone rubber products is that the formula of the dispersant and silicone oil in the raw materials does not reach a certain ratio, or there is a problem with the raw materials, resulting in uneven mixing of the silicone rubber raw materials when adding color glue. Some analysts believe that the toner coloring effect is not good, the color dispersion is too large, and it is incompatible with silicone rubber materials, leading to fading problems. In short, the fading problem of color glue can basically be determined to be a problem with the raw material of color glue.
2. Raw material issues
Yellowing and uneven color: Most of the main products are transparent or white products. Many white silicone rubber products or transparent products will turn yellow and discolor under the action of catalysts due to high processing temperatures or high ambient temperatures and the influence of heat. The main reason for this phenomenon is that the main raw material in the catalyst, tetramethylammonium hydroxide, failed to pass through the environment correctly during the mixing stage. Due to the effects of temperature, humidity and oxidation, the prepared raw materials may lose their anti-yellowing effect. In nature, the product turns yellow after passing through the catalyst. Therefore, the raw rubber formula of the material should be considered in raw rubber production.
Generally, "vinyl resin" is a silicone raw material commonly used in most rubber compounds, and the proportion of this material usually needs to be less than 1%. If it exceeds this range, the polyethylene silicone rubber material will turn yellow, while the common methyl vinyl silicone rubber will have vinyl silicone. Therefore, the problem is that the silicone rubber product you purchased turns yellow. This is due to the silicone rubber. The formulas of raw material manufacturers are different, and the vinyl resin content exceeds 1%, causing yellowing.
3. Raw material catalyst issues
In fact, if silicone rubber does not add a catalyst, it will produce a yellowing effect. Therefore, the silicone rubber products you purchase achieve the yellowing effect through raw material processing, and catalysts can generally play a certain role in preventing yellowing. However, it is not important to pay attention to the anti-yellowing effect of each brand of catalyst debugging formula, because the catalyst not only needs to be prepared for the anti-yellowing effect, but also needs to achieve good sulfur addition effect, odor problem and material dispersion effect. When preparing for other performances, it is impossible to control several performances at the same time to achieve the best state. Therefore, the silicone rubber product you purchase is likely to have good tensile toughness, but will develop yellowing over time.
4. Caused by use
In addition to the raw materials, the yellowing and fading of silicone rubber products also depend on their scope of use and environment. If it is used in different environments for a long time, such as high temperature, oil pollution, strong light, etc., the proportion of yellowing mainly depends on the material characteristics of the product.
Ray Xian
Company Website:www.siliconesupplier.com
