Porous polyvinylidene fluoride resin membrane and preparation thereof

Abstract

Abstract PURPOSE:To obtain porous membrane suitable for a membrane filter and excellent in permeability and strength, by a method wherein a solution containing polyvinylidene fluoride resin is cast into film and the obtained film is coagulated by contacting the same with an aqueous solution containing a solvent for said resin. CONSTITUTION:Film is formed from a solution prepared by dissolving polyvinylidene fluoride resin in a solvent such as N-methyl-2-pyrrolidone or dimethylformamide in concn. of 8wt% or more. The resulting film is coagulated by contacting the same with an aqueous solution containing 20vol% or more solvent for the polyvinylidene fluoride resin for at least 10sec to obtain objective polyvinylidene fluoride resin porous membrane. The obtained porous film has fine pores with an average pore size of 0.05-5mum in the surface layer thereof and contains no microvoids of 20mum or more in the crosssectional direction thereof and the permeation speed of pure water is in a range of 5X10<-2>-2g/cm<2>.sec.atm at 25 deg.C.

Inventors

• 👤 Fumio Ueda
• 👤 文雄 上田
• 👤 Ko Mori
• 👤 森　興

Bibliographic Details