The yellowing and fading of silicone rubber products used in daily life has become a shadow for many of our consumers. They believe that silicone rubber materials will yellowing and fade, such as cheap silicone rubber phone cases, sports bracelets wearing silicone rubber jewelry, etc. However, from a professional point of view, silicone rubber products will not appear this fading, yellowing phenomenon, this is only caused by the difference between product and material manufacturers, and the more outrageous the fading or color overflow, the more unacceptable, so what is the reason for the color problem?

In general, we can understand the quality of the color of silicone rubber products from two aspects. Overall, this phenomenon does not occur in all products. This type of problem comes mainly from the material. If the material cannot reach the performance, the products produced by the silicone rubber processing manufacturers will naturally not reach the performance.

First, the problem of color glue
Colorant is the main material for coloring silicone rubber products. The main materials are composed of toner, silicone oil, dispersant and silicone rubber raw materials. The main reason for the discoloration of silicone rubber products is that the formula of dispersant and silicone oil in its raw materials does not reach a certain proportion, or there are problems in the raw materials, which leads to uneven mixing of silicone rubber raw materials when adding color gel. There is also an analysis that its toner coloring effect is not good, the color is too dispersed, and it is incompatible with silicone rubber materials, resulting in fading problems. In short, the fading problem of the color glue can basically be determined as the problem of the raw materials of the color glue.

Second, the problem of raw materials
Yellowing, uneven color: The main products are mostly transparent or white products. Many white silicone rubber products or transparent products will have yellowing and discoloration due to the high processing temperature or high ambient temperature and the influence of heat under the action of catalyst. The main reason for this phenomenon is that tetramethylammonium hydroxide, which is the main raw material in the catalyst, fails to pass through the environment correctly during the mixing stage, and due to the influence of temperature, humidity and oxidation, the formulated raw material may lose its intrinsic anti-yellowing effect, and the product will turn yellow after passing through the catalyst. Therefore, the raw rubber formulation of the material should be considered in the production of raw rubber.

In general, "vinyl resin" is a silicone raw material commonly used in most rubber compounds today, and the proportion of this material usually needs to be less than 1%. If it exceeds this range, the polyethylene silicone rubber material will yellow, and the common methyl vinyl silicone rubber will have vinyl silicon, so the problem is that the silicone rubber product you buy is yellowing, which is due to the different formulas of this silicone rubber raw material manufacturer, and the vinyl resin is more than 1%, resulting in yellowing.

Third, the problem of raw material catalysts
In fact, if a catalyst is not added to silicone rubber, it will have a yellowing effect. Therefore, the silicone rubber products you buy are yellowing effects achieved through raw material processing, and the catalyst can generally play a certain role in preventing yellowing. However, it is not important to pay attention to the anti-yellowing effect of the debugging formula of each brand of catalyst, because the catalyst not only needs to be formulated for 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 not possible to control several properties at the same time to achieve the best state. As a result, the silicone rubber product you buy is likely to have good tensile toughness but will show yellowing over time.

Fourth, caused by use
In addition to the raw materials, the yellowing and fading of silicone rubber products also depend on the scope of their use and environment. If it is used in different environments for a long time, such as high temperature, oil stain, strong light, etc., the proportion of yellowing mainly depends on the material characteristics of the product.

About injection liquid silicone rubber,please check the details: High Strengh Liquid Silicone Rubber IOTA 28-Series
About fluorosilicone rubber,please check the details: Fluoro Silicone Gum (IOTA 110-F series)
About ethyl silicone oil,please check the details: Polyethylsiloxane Fluids IOTA 2056 PES
About leather silicone rubber,please check : IOTA Liquid silicone rubber for silicone leather