What are the reasons for the yellowness of ABS recycled materials

ABS plastic will turn yellow when used for a long time. What shall I do? What causes it?

　　Generally speaking, the yellowing of ABS recycled plastic particle products is caused by the aging or degradation of materials. Generally, PP is caused by aging (degradation). Due to the presence of the side group on PP, its stability is not good, especially in the case of light. Generally add light stabilizer.

　　（1） As for ABS regeneration particles, because there is no side base, the general processing or use of the initial yellowing is not a lot. ABS recycled particles will turn yellow, which has a great relationship with the product formula.

　　(2) Yellowing may be related to hydrothermal oxidation and ultraviolet rays, which will be heated (electric heating) in the process of use. If it is humid, it is easy to be further oxidized, leading to yellowing and embrittlement. Or because of the problem of ABS processing technology, the long residence time of injection molding leads to the fast processing requirements of ABS, short cycle time, mold temperature 60-70), leading to degradation.

　　(3) In short, the main advantages of the air vent of ABS material are that it will not condense, it will not deform under high temperature, and it is elegant and beautiful (the temperature of ABS thermal deformation can reach 95 ℃). In the process of producing ABS tuyere profile, antioxidants and light stabilizers are added in it, so as to reduce the appearance yellowing caused by UV absorption.

　　(4) ABS oxidation resistance is not very good, in the light or wind and rain environment is easy to turn yellow. Without additives, it is very serious that the light turns yellow after a long time, even if it is white. Therefore, pay special attention to the light when storing ABS particles.

　　(5) White turns yellow. Generally, most of the particles are added with whitening powder, so the products after injection molding are as white as jade. After a period of time, the whitening powder material will lose its whitening effect under the effect of sunlight, so it will make the product yellow. Generally, the product after yellow can not return to the original white.