Users often notice that TPU flame-retardant masterbatches, particularly transparent ones, gradually turn yellow after extended use. This is evident in items like phone cases, which commonly become yellowed after a few months. Even TPU exposed to sunlight can exhibit yellowing.

TPU is a high polymer material structure composed of many different small molecules. The molecular structure of TPU raw materials can only be used to produce products with low requirements. If you are making transparent products and also require resistance to yellowing, you must inform the TPU manufacturer in advance to carry out modifications on the flame-retardant masterbatch of TPU to meet your needs.