Each substance has a specific wavelength region of light that it absorbs. When each substance absorbs light, it acts on the molecules inside the substance and causes various changes.
In the case of resins in particular, it is well known that irradiation of UV light can cause a yellowish discoloration (yellowing) of the surface color.
Using generally used resins [PMMA (transparent, white), ABS, PC (white), PET (white)], we conducted a simple test to confirm yellowing by UV irradiation and measured the relationship between the wettability of the surface.
Comparison of yellowing before and after UV irradiation. The yellowing can be visually confirmed after 180 seconds of irradiation.
The contact angle of all the sample materials was 20 to the latter half of 40° after 180 sec. of irradiation, and the wettability was improved before the yellowing.
*There are individual differences depending on the material used.