[BULK] Wet-process PE Base Film lithium-ion battery separator

Wet process, also known as phase separation or thermally induced phase separation (TIPS), involves mixing high-boiling-point hydrocarbon liquids or low-molecular-weight substances with polyolefin resin. The mixture is heated to melt, and the molten material is cast into a thin sheet. Upon cooling, phase separation occurs, followed by uniaxial or biaxial stretching of the sheet. Finally, a volatile solvent is used to extract the liquid, resulting in an interconnected microporous membrane material suitable for a wide range of applications. Representative companies utilizing this method include Asahi Kasei, Tonen, and SK from Japan. The separators produced using the wet-process biaxial stretching method exhibit higher longitudinal and transverse strength due to the stretching process and are primarily used for single-layer PE separators.