[Study on spectral properties of natural plant ultraviolet absorbent].

Natural plant ultraviolet absorbent is a safe cosmetic-typed ultraviolet additive, with no side-effect and bright future. Natural plant ultraviolet absorbent is ground from ultraviolet absorbing plant into organic solvent under dry-vacuum condition. This new type of ultraviolet absorbent has brown colour in solid form, but when it mixes with alcohol and water, its colour changes to light yellow in liquid form. This paper focuses mainly on using ultraviolet/visible spectrometer to examine its spectral properties under ultraviolet light. The result shows that this absorbent has a relative transmittance below 0.2% in the UVC and UVB zones, while in the UVA zone around 375 nm, the value raises up only to 2.1%. This concludes that the natural plant ultraviolet absorbent has a high absorbing ability under ultraviolet light and can withstand ultraviolet light with long wavelength.