What are the preservation methods of waterproof and breathable membrane

① Wet preservation: The key to wet preservation is to always keep the membrane surface wet with preservation solution. Preservation solution can use the following formula: water: glycerin: formaldehyde = 79.5: 20: 0.5. The role of formaldehyde is to prevent the growth and reproduction of microorganisms on the surface of the membrane and to prevent erosion of the membrane. The purpose of adding glycerin is to lower the freezing point of the preservation solution and prevent damage to the membrane due to freezing. The formaldehyde in the formula can also be replaced by copper sulfate and other fungicides that do not harm the membrane. The preservation requirement of cellulose acetate film is temperature 5～40 ℃, pH=4.5～5, and the temperature and pH of non-cellulose acetate film preservation can be wider.

② Dry storage: Waterproof and breathable membranes are often provided in the market in a dry state, because it is convenient for storage and transportation. In addition, if the wet film is to be stored in a dry method, the film must also be treated by the following methods. The specific method is: the cellulose acetate membrane can be soaked in 50% aqueous glycerin or 0.1% sodium dodecylsulfonate aqueous solution for 5-6 days, and dried at a relative humidity of 88%. Polysulfone membranes can be dried at room temperature with 10% glycerin, sulfonated oil, polyethylene glycol and other solutions as dehydrating agents. In addition, the surfactant also has a good effect on the deformation of the pores of the protective film.