The production process is visible for knitted garden hoses
After receiving the PU steel hose, many customers will find that the PU steel hoses produced in different batches have different transparency, some are transparent, white is transparent, and some are yellow and yellow. So why does the PU hose turn yellow?
First, the anti-oxidation effect caused by the yellowing of the PU steel wire hose
Most of the PU products, whether PU hose, soft and hard foam, elastic, PU leather or PU paint, mainly choose TDI or MDI as raw materials. However, whether it is TDI or MDI, since the benzene ring is directly linked to the isocyanate group, the large pi bond on the benzene ring forms a conjugation with the adjacent NCO, under the action of light, heat, oxygen, especially ultraviolet rays. The urethane bond is decomposed to form an aromatic amine, and the benzene nucleus on the aromatic amine is rearranged by oxidation to form a chromophoric group such as a quinoid structure, so that the PU steel hose produced is easy to yellow and cannot be maintained for a long time. Highly transparent white.
Second, the ultraviolet light causes the PU steel wire hose to yellow
When receiving the goods of the PU steel hose, if it is not used directly, choose a warehouse with a dark light when storing, and not directly in direct sunlight.
Solve the yellowing method of PU steel hose
1. During the production and storage process, the inert gas is insulated as much as possible from the contact with oxygen. Or adding an antioxidant and a UV absorber can effectively prevent yellowing from delaying PU.
2. The main culprit causing oxidation and yellowing of PU steel wire hoses is ultraviolet light. The source is mainly sunlight. Therefore, especially in the face of the production of PU spiral steel wire reinforced hose, customers who need to use it outdoors must order Add PU steel hose with UV protection.
Of course, PU steel tube production batches are relatively transparent, and storage time will be yellow, but neither transparent nor yellow will affect the performance of PU steel hose. Moreover, many customers are also more interested in PU steel hoses, because the original imported PU hoses are yellow, because the import time is longer, most products will turn yellow after coming to China.
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