UV Absorbers: A Key Component of Cosmetic Sun Protection

Speaking ofUV absorbers, an important component of cosmetic sun protection, they shield our skin from external UV. To protect skin from UV, ingredients are roughly divided into two types: UV scattering agents and UV absorbers. As for the mechanism by which UV scattering agents protect the skin, they do not—despite the name—reflect UV through the skin; the main material is a mineral-oil-based titanium dioxide. As for the mechanism by which UV absorbers protect the skin, mainly they absorb UV—as the name implies—so it is not transmitted to the skin. When bathed in UV light, the UV absorber's molecular structure changes slightly. Ultraviolet
　　UV absorbersLight stabilizers are commonly called UV absorbers. According to molecular structure, UV absorbers are divided into benzophenone and benzotriazole types. Such light stabilizers use their own molecular structure to convert the light energy striking colored plastic articles into heat, preventing the colored-agent molecular structure (such as the conjugated double-bond chromophores of organic colorants) from being destroyed by light energy, and avoiding photo-oxidation of the plastic material. UV absorbers are light stabilizers that directly protect colorants and the appearance of colored plastic articles.
Of course Kunming has its civil and military sides—the military is the Yunnan Military Academy, the civil is Southwest Associated University, the greatest institution of higher learning in China to this day, arguably unmatched before or since. Sadly, only a small room of the associated-university site remains, on the campus of Yunnan Normal University on Yieryi Street in Kunming. Next to the site are only the Martyrs' Tomb of December 1 and the cenotaph of Mr. Wen Yiduo. On the Yunnan Normal campus there is a statue of Mr. Wen Yiduo and a 'Democracy Lawn' where students may sit or lie freely as an expression of democracy—one of our favorite spots in student days. The normal-university campus has a pond
　　UV absorbersMost colorants, especially inorganic-pigment colorants, can provide a certain degree of light stabilization when used alone in plastic articles. For colored plastic articles used outdoors long-term, colorants alone cannot raise the article's light-stability performance. Only by using light stabilizers can the photo-aging rate of colored plastic articles be durably and effectively suppressed, significantly improving their light-stability performance. Hindered amine light stabilizers (HALS) are a class of sterically hindered organic amine compounds that, because they decompose hydroperoxides, quench excited-state oxygen, capture free radicals, and have a recyclable active group,