▎ 摘　　要

NOVELTY - Flash evaporation spinning gradient pore structure ultrafiltration flat membrane comprises a functional layer, a transition layer and a support layer, where the functional layer is spun on the surface of the transition layer by flash spinning, the transition layer is spun on the surface of the support layer by a flash spinning method, and the pore size of the flat membrane increases continuously from the functional layer to the support layer, presenting a gradient pore structure. USE - The flash evaporation spinning gradient pore structure ultrafiltration flat membrane is used in water treatment separation membrane preparation technology for seawater desalination, heavy metal separation, medicine separation, and concentration of food. ADVANTAGE - The method provides flash evaporation spinning gradient pore structure ultrafiltration flat membrane prepared by flash spinning technology, the flat film hole diameter distribution is uniform, the interception rate is high, and the pollution resistance is high. The method has simple process, and easy control process condition. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a method for preparing the flash evaporation spinning gradient pore structure ultrafiltration flat membrane, which (i) configuring functional layer spinning solution by mixing and stirring polymer materials, solvents, co-solvents, and functional materials, dissolving and filtering at 30-200℃, (ii) configuring transition layer spinning solution by mixing and stirring polymer materials, solvents, co-solvents, and functional materials, dissolving and filtering at 30-200℃, (iii) preparing transition layer by spinning the transition layer spinning solution on the support layer by a flash spinning method, (iv) preparing functional layer by spinning the functional layer spinning solution on the transition layer by flash spinning method, and (v) performing flat film by hot pressing the functional layer, transition layer and support layer.