What is the cause of UV adhesive yellowing? How to improve the performance of UV adhesive yellowing resistance?
Many customers use UV adhesive before the glue will be considered after the use of glue will not turn yellow, concerned about how long it will occur yellowing? So what exactly is UV glue yellowing? In fact, UV glue yellowing is mainly the formation of aging, by heat and oxygen molecules, the application of materials will be oxidized over time, resulting in the breakage of the -C-C-bonds and the rupture of the double bond resulting in yellowing of the material. In layman's terms is the UV adhesive in the sun, ultraviolet radiation for a long time or in the heat, oxygen, stress, trace moisture, impurities, improper process under the action of the phenomenon of color yellowing, it is called yellowing.
What are the reasons for the yellowing of UV adhesive?
1, the size of the light intensity
UV glue have their own light intensity parameters, within this parameter uv glue is not yellowing, if more than this parameter may be yellowing;
2, curing time
UV glue curing time if too long or too short may lead to yellowing of the glue easily;
3, wavelength mismatch
Most UV adhesive need 365nm wavelength of ultraviolet light for curing, if the use of other wavelengths of ultraviolet light may lead to yellowing of the glue;
Can UV adhesive always resist yellowing?
No. Aging and discoloration are a time, always non-yellowing, in theory can not be reached, but if you consider the product a few years of a service life, in the normal life of the product during the non-yellowing technology can be done.
How to enhance the yellowing resistance of UV adhesive performance?
Enhance the performance of UV adhesive yellowing resistance, an effective way is to add antioxidants and ultraviolet absorbers in the UV adhesive formula, can effectively prevent and delay the yellowing phenomenon. As more types of antioxidants, in general, based on the different models of UV adhesive production process, raw materials, solvents, additives, fillers, which stage of yellowing and the degree of yellowing, and the use of different antioxidants.
In short, the use of antioxidants and ultraviolet absorbers may not be able to fundamentally solve the problem of UV adhesive yellowing, but in a certain use of the environment and conditions, can be more effective in preventing oxidative yellowing of the product.
