Sleep mask refers to the mask that is directly applied to the face to sleep after finishing basic skin care at night; Generally, it should be cleaned the next morning and cleaned normally. Generally, sleep masks are gels or creams, just like a layer of skin care products. Sleep mask can also be understood as an upgraded version of cream, which is characterized by no washing and can be worn overnight. Sleep mask is a popular mask in recent years, which is wrapped in the stratum corneum of the skin and provides moisture, humectant and softener for the stratum corneum. At the same time, it also has good film forming property. On the basis of skin care night cream, a little polymer compound with film-forming performance is added, which has a certain film-forming "sealing" performance and can keep the skin from flowing out.