国产精品一区在线观看高清免费_色阁阁日韩欧美在线_欧美成人性生活视频在线观看_韩国强大喷奶水av片_日韩精品欧美大片资源_欧美一区二区三高清视频_蜜桃传媒AV免费观看麻豆_无码中出亚洲性爱视频_91久久另类重口变态_亚洲中文字幕无码ⅴa

Sunscreen

Time:2019-06-24 Views:1798

Sunscreen is a cosmetic that protects against sunburn and sunburn by adding a sunscreen that blocks or absorbs UV rays. According to the principle of sun protection, sunscreen can be divided into physical sunscreen and chemical sunscreen.
Sunscreens need to choose different SPF or PA values depending on the specific target to achieve the purpose of sun protection. The principle of sunscreen is to isolate the skin from UV rays. Sunscreen lotion and sunscreen, the main difference is the physical properties, the general moisture content of the cream is about 60%, it looks more "thick", it is creamy; and the emulsion, the water content is more than 70%, it looks thin, there are fluidity. Generally, the lotion is more refreshing than the cream because the water content is relatively high, but the formulator can still use different oily ingredients and thickeners to adjust the "greasy" degree of the cream. Therefore, it is still necessary to look at the product itself.

  • Up: SPF
  • Next: No news