Antifouling finishing is usually achieved through water and oil repellent finishing [5]. Generally, the finishing agent with special functions is applied to the fabric through the finishing method of impregnation and dip rolling. It can usually form physical, chemical or physicochemical interaction with the fiber, so as to change the surface properties of the fiber. When the finishing agent reduces the critical surface tension of the fabric to less than the surface tension of water and can not be wetted by water, this finishing process is called water repellent finishing; If the critical surface tension of the finished fabric is further reduced to lower than the surface tension of oil, and the fabric can not be wetted by water or oil, this process is called water and oil repellent finishing.
Fluorinated water and oil repellent finishing agents are different from polysiloxane water repellent agents. They have both water and oil repellent functions. Therefore, now polysiloxane water and oil repellent finishing agents are gradually replaced by fluorinated polymer water and oil repellent finishing agents. The surface tension of CF3 group in fluorinated compounds (6 Mn / M) is much lower than that of water (72.8 Mn / M) and common oils (20-30 Mn / M) [25]. The fabric treated with this kind of finishing agent shows the characteristics that it is difficult to be wetted by various aqueous and oily liquids. The advantage of fluoropolymer finishing agent is that it only needs a small amount of finishing agent to treat the fabric, which can have good waterproof and oil proof effect and excellent air permeability. In the past, the fluorocarbon chain in fluorine-containing finishing agents was generally perfluorooctyl with 8 carbon atoms, and its synthetic raw material was perfluorooctyl sulfonyl derivatives (PFOS). PFOS has extremely high chemical stability. It can exist in the environment for a long time and form biological accumulation, which is potentially harmful to the natural environment and human health. Now the new products are mainly C6.
