Why does styrofoam turn yellow?

Why does styrofoam turn yellow

About polyurethaneFoam glueyellowing The reasons are from the perspective of technology and marketangleAnalysis, the key points are as follows reasons, PleaseFor reference:

1. The resin of ordinary polyurethane foam is exposed to UV raysIlluminationDown It is easy to produce yellowing chromogenic groups, causing the foam rubber to turn yellow and powder, that is, aging.

Yes Professionalsspecializes in polyurethane foaming Regarding the problem of glue yellowing, we screened and analyzed the main raw materials such as resin, curing agent, nitrocellulose, etc. to explore the yellowing resistance of foam rubber. The experimental results are as follows:

(1）Polyurethane hair The yellowing of foam is mainly caused by the conjugation of the benzene ring of the aromatic curing agent with the amino ester in the resin, resulting in oxidative rearrangement to form a quinone structure with a chromophoric group.

（2 ）The addition of nitrocellulose to polyurethane coatings will promote its yellowing. However, since nitrocellulose has a good effect on improving the overall performance of foam rubber, attention should be paid to controlling its amount during production. .

（3 ）When the paint is freeTDI（Toluene diisocyanate ）When the content is high, it will not only accelerate the yellowing and powdering of the foam rubber, but also affect the human body’s nervous and immune systems and cause respiratory diseases.

2. SomestyrofoamManufacturer fordropLowProduction font>cost, use cheap anatase titanium dioxide or lithopone to help increase The aging speed of styrofoamThe degree of has caused damage to the proper performance of the foam rubber. This kind of The behavior is truly disgraceful.

Solution:UV absorber The addition of it has a significant effect on the yellowing resistance of the foam rubber. However, in view of factors such as miscibility with the base material and price, the appropriate amount can be added.