TAGS: Skin Care
Sun Care
Kao researchers of Skin Care Research Laboratory and Processing Development Research Laboratory have successfully developed a new protective technology that blocks near-infrared (NIR) rays in a highly efficient manner for controlling skin surface temperature elevation caused by sunlight. The study results confirmed that this new technology reduces both skin surface temperature increase and the sensation of heat caused by exposure to sunlight.
Thin Titanium dioxide Flakes to Block NIR
The protection technology consists of thin titanium dioxide flakes that block the near-infrared (NIR) rays in sunlight in a highly efficiently manner. Kao has tested a variety of materials for blocking near-infrared (NIR) rays by light scattering but could not find satisfactory results for controlling skin surface temperature.
Accordingly, by focusing attention on principle factors related to light wave interference, a new material capable of selective blocking of the NIR wavelength was investigated. The findings showed that a high NIR protection capability could be attained by controlling the thickness of the thin titanium dioxide flakes, a cosmetic raw material.
Study Changes in Skin Surface Temperature
For the experiments, different sunscreen formulations were applied to subject’s forearms, including an NIR protective material combined with UV protection formulation (UV & NIR protective formulation) and a conventional sunscreen formulation (UV protective formulation).
Following exposure to artificial sunlight, changes in skin surface temperature were determined. The average skin temperature of forearms without sunscreen application (control group) was elevated by 6.5˚C after five minutes of exposure, while that of forearms with the UV protective formulation (conventional sunscreen formulation application) was also increased in a similar manner.
In contrast, the average skin temperature increases in forearms with the UV & NIR protective formulation (new combined sunscreen formulation application) was 5.5˚C, a temperature elevation lower by an average of -1˚C and maximum of -1.6˚C.
Subjective evaluations of heat and burning sensation at five minutes after exposure were also performed. Those findings showed that visual analog scale (VAS) scores were significantly lower in the group that received application of the novel UV and NIR protective formulation as compared to both the control group without application and the group applied with the conventional sunscreen formulation.
The findings obtained will be implemented for further development of sunlight protective care technology.
Source: Kao