How to deal with yellowing of TPU elastic tape

Yellowing is an unavoidable problem of TPU material and TPU products, which is also the common failing of plastic and rubber. Therefore, manufacturers and designers find lots of methods to deal with the problem. Here we list some methods below.

1. Change color

Yellowing will be much more obvious on clear and white TPU products. But TPU products in black, royal blue or other dark colors will not be yellowing seen with our naked eyes.

2. Avoid sunlight or high temperature

When exposed to sunlight or high temperature, TPU will get yellowing much faster. If TPU tape packed in sealed carton and then stored in cool, the TPU tape can keep original clear color in 3 years. Contrarily, TPU tape may get yellowing in 2 months.

3. Avoid contamination

During the process of TPU tape manufacturing, stuffs should decrease direct touching with TPU material or TPU tape. Because organic solvent such as sweat will lead to yellowing of TPU.

4. Choose anti-UV TPU raw material

Anti-UV raw material has performance of anti-yellowing. TPU material manufacturer added anti- ultraviolet-ray accessory ingredient already during the pelleting process.

5. Add yellow resistance agent

Yellow resistance agent is not cheap. Adding yellow resistance agent asks for some skill and technology. Mixing well is important. Or TPU products may be yellowing partly.

6. Spray anti-yellowing paint

After spraying anti-yellowing paint, TPU products will receive protect layer on surface. The protect layer helps to separate air and TPU. The isolate-air TPU will slow down its rate of yellowing development.

7. Change material

Generally, manufacturers choose aromatic TPU material because of cost and workability. Benzene ring in aromatic TPU is good at absorbing ultraviolet-ray, which is the element that results in TPU yellowing. Thus, TPU manufacturers develop aliphatic series TPU, which doesn’t contain benzene ring. That means aliphatic series TPU won’t get yellowing. However, aliphatic series TPU has its shortage of course. The first one is its narrow range of hardness, which only range from 80A to 95A. Secondly, aliphatic series TPU requests high processing technology. Thirdly, this type of anti-yellowing TPU is not clear enough. So products thicker than 2 mm will be matte or white.