Why new silicone product look yellow?

There are three reasons, curing agent, processing technology and raw materials are poor quality

  • Curing agent

The performance of the curing agent can be divided into general and anti-yellow. It is applied in the following two aspects:

The general one is non-anti-yellowing curing agent, it can be used for non-exposed silicone products which are relatively dark colors or low color requirement.

The other one is an anti-yellow curing agent, it can be used for silicone products that need to be exposed to light or certain chemicals or lighter and brighter colors, and a higher requirement of colors.

  • Processing technology

During molding, the clear silicone turns yellow. The main problems are

  1. Mold’s temperature is too high
  2. Vulcanizationtime is too long
  3. Turn yellow after the second Vulcanization
  • Raw materials are of poor quality

Sometimes we add an anti-yellow curing agent to the silicone rubber, but the clear silicone products still look yellow after molding. It may be the silicone rubber material’s anti-yellowing ability is too poor. The only solution is to change the raw material.

Although the excellent weather ability and anti-aging properties of silicone products. However, sometimes silicone products turn yellow after molding. In order to prevent this kind of situation, we should choose the correct curing agent. During processing, we should strictly control the temperature of tools and their curing time, and pay attention to the raw material resistance of yellowing.

silicone phone case

Why clear silicone cases turn yellow over time?

Clear phone cases are normally made from silicone that is popular for its inexpensive and flexible properties. Unfortunately, these silicone turn yellow as they age. The main reason is because of the ultraviolet radiation of the light. If you usually use your smartphone with the case outdoors, the case will turn yellow after long-time exposure to the light. Of course, UV radiation is not the only element that can cause the silicone to age. This natural process is accelerated when they are exposed to excessive amounts of chemicals, light, and heat.

In addition to this, the constant friction during normal use, and the sweat on the hand or the oil on your face cause the oxidation reaction will also turn the cell phone cases yellow.

Rather than just being a stain, the yellowing is part of the material degradation. But yellowing does not affect its basic use such as hardness and service life.


How to remove the yellowness of silicone cases at home?

how to remove yellownessDetergent powderpaint thinner

Take an empty bowl with tissue paper in it.

Put the Detergent powder in the bowl, mix water & detergent powder, add more tissue paper( tissue papers will help to stick to the cover and will remove it better), then add vinegar in the mixture, stir it well. Now put a yellowness silicone cover in it. Leave it for 5 minutes. Then add paint thinner. Leave it for 5 minutes again, stir it well and cover it with tissue, leave it for 20 to 30 minutes. Finally, take the silicone case out, it looks good and transparent again.