The yellowing and fading of silicone products used in life has become the shadow of many consumers. It is believed that the silicone material will have yellowing and fading, such as low-cost silicone mobile phone case and sports bracelet wearing silicone jewelry, etc., but professional From the point of view, silicone products do not have such a yellowing phenomenon, but only for different products and materials, but more outrageous color or color is more unacceptable, so what is the cause? What about color?
On the whole, we can understand the quality of the color of the silicone products from two aspects. In general, not all products will have this phenomenon. This kind of problem is mainly due to the material, the material can not achieve the performance, then The products produced by the silicone processing manufacturers naturally do not reach the performance.
Color glue problem:
Color glue is the main material for debugging color of silica gel products. The main materials are composed of toner, silicone oil, dispersant and silica gel. The main reason for the fading of silica gel products is that the dispersant and silicone oil blending formula in its raw materials have not reached a certain level. The proportion of the raw materials or the raw materials causes the silica raw materials to be mixed unevenly when adding the colored rubber. There are also reasons for the coloring effect of the toner is not good, and the color dispersion is too large to be incompatible with the silicone material, resulting in fading. In short, the problem of dyeing and fading in the color paste can basically determine the problem of the raw material belonging to the color paste.
Raw material issues:
Yellowing, uneven color: Most of the main products are made of transparent or white type products, many kinds of white silica gel products or catalysts of transparent color products, high processing temperature or high ambient temperature and heat There will be yellowing discoloration of the product, and this phenomenon is mainly caused by the tetramethylammonium hydroxide as the main material in the catalyst. If the environment fails to pass the environment, temperature, humidity and oxidation, it may lead to the production. The raw material that is out of the essence loses the anti-yellowing effect, and the phenomenon of yellowing of the product after passing through the catalyst, so it is necessary to look at the raw rubber formula of the raw material in the production of raw rubber.
Usually, “vinyl resin” is a kind of silicone resin which is commonly used in most of the current rubber compounds. The ratio of this material usually needs to be less than 1%. If it exceeds this range, then the polyvinyl silicone rubber material is used. There will be yellowing, and the usual methyl vinyl silicone rubber will have the appearance of vinyl silicone resin, so the problem is that the silicone product you purchased is yellowish, so it is the formula of this silicone raw material manufacturer. Different appearances of vinyl resins >1% or more result in yellowing problems.
Raw material catalyst problem
In fact, if the silica gel is not formulated with a catalyst, it will have a yellowing effect. Therefore, the silicone products you buy are all treated with the yellowing effect from the raw materials, and the catalyst can generally go. To a certain anti-yellow effect, it is only important that each brand's catalyst debugging formula has different emphasis on yellow fading, because the catalyst is not only to be formulated for anti-yellow effect, but also needs to achieve good vulcanization effect, odor problem and material. The dispersing effect, when blending other properties, can not control several properties at the same time to achieve the best state, so the silicone products you purchase are likely to have good tensile toughness, but yellowing over time.
The use of: the yellowing of the silicone product faded out of the raw materials depends on its scope of use and the environment, if used under different conditions for a long time such as (high temperature, oil, glare), etc., then yellow The proportional effect depends mainly on the material properties of the product.