What causes the yellowing of ABS recycled plastics

　　ABS plastic in use for a long time will turn yellow, what is the cause?

　　Generally speaking, the yellowing of ABS recycled plastic granule products is caused by the aging or degradation of materials. Generally speaking, PP is produced by aging （degradation）。 Due to the existence of side groups on polypropylene, its stability is not good, especially in the case of light. Generally, light stabilizer is added.

　　（1） As for the recycled ABS particles, there is no side base, so it is not very yellow in general processing or early use. ABS regeneration particles will turn yellow, which has a great relationship with the formula of the product.

　　（2） Yellowing may be related to moist heat oxidation and ultraviolet rays. It will be heated （electric heating） in the process of use. If it is moist, it is easy to be further oxidized, resulting in yellowing and embrittlement. Or because of the problem of ABS processing technology, the long residence time during injection molding leads to the requirement of rapid ABS processing, short cycle time, and mold temperature of 60-70）， resulting in degradation.

　　（3） In short, the main advantages of ABS material tuyere are that it will not condense, it can resist high temperature and will not deform, and it is elegant and beautiful （the thermal deformation temperature of ABS can reach 95 degrees）。 In the production process of ABS tuyere profiles, antioxidants and light stabilizers are added in the process, so as to reduce the yellowing problem caused by UV absorption.

　　（4） ABS oxidation resistance is not very good, in the light or in the wind and rain environment is easy to turn yellow. In the case of no additives, yellowing is very serious after a long time of illumination, even if it is white. Therefore, special attention should be paid to the illumination factor when preserving ABS particles.

　　（5） White to yellow, generally in the particle material added whitening powder material is the majority, so the injection molding product is as white as jade. After a period of time, whitening powder material in the role of sunlight will lose the whitening effect, so it will make the product yellowing, yellowing products are generally unable to restore the original white.