Why does the color of PVC edge banding fade? Shanghai Angmi Edge Banding Manufacturer introduces the reasons for you.
1. Heat, oxygen, light aging discoloration
Many people believe that to solve the problem of inconsistent color of PVC edge banding processing, as long as the processing temperature of the yellowing profile production line is lowered, the color difference can be reduced. However, some people believe that the main and auxiliary raw materials such as PVC, CPE, stabilizers, etc. that have a greater impact on yellowing will have different color differences during processing. In this case, even if a certain amount of brightener and anti-light aging agent are added alone, it will not have much effect.
The main manifestation of heat, oxygen and light aging discoloration is yellowing of profiles. Some stabilizer manufacturers claim that using their products can reduce the number of parts and reduce costs compared with similar manufacturers when promoting their products. As a result, although PVC profiles with relatively satisfactory appearance can be produced, in the recycling of waste products and under the harsh process temperature requirements, due to its insufficient thermal stability efficiency, the damage to the PVC molecular structure cannot be observed by the naked eye, so the following situations occur during production:
(1) Chengdu PVC edge banding is found to have inconsistent color during processing (slight deviation in color is allowed);
(2) The profile turns yellow obviously after heating and deformation;
(3) The state is good after heating, but the profile turns gray not long after being made into doors and windows. The profile does not turn yellow during normal production, but turns yellow when it is later made into window products.
In the process of profile production, when the basic conditions such as raw materials and molds remain unchanged, if the temperature of the plasticizing section and the homogenizing section is increased by about 5°C, the resulting profile will tend to turn yellow, which also indicates that its thermal stability efficiency is insufficient and the amount of heat stabilizer added should be increased, especially when whitening agents such as fluorescent brighteners are added to the formula. Insufficient heat stabilizer causes discoloration of PVC and PVC profiles, and the whitening effect is not obvious.
