Preparation of gas separation membrane

Abstract

Abstract PURPOSE:To obtain a composite membrane having an ultrathin active layer free from a pinhole, by applying coating to a homogenous non-porous support before making said support porous by stretching. CONSTITUTION:A thermoplastic crystalline polymer with an arrival crystallization degree of 20% or more is formed into a hollow yarn shape at melting temp. of Tm-Tm+100 deg.C (wherein Tm is a crystal m.p.) by melt spinning. A draft ratio is set to 5-10,000. The formed hollow yarn is cooled in a temp. range of glass transition temp. Tg-50 deg.C-Tm-50 deg.C and subsequently subjected to heat treatment at temp. of Tg+20 deg.C-Tm-5 deg.C. A substance forming a polymer film is applied to the surface of the obtained membrane in a thickness of 0.001-50mum. The viscosity of the coating solution is 0.5-500cp and the concn. of the polymer is 0.01-10wt%. This membrane is subjected to cold stretching at a stretching magnification of 1.05-3 at temp. of Tg-50 deg.C-Tm-10 deg.C. A stretching speed is pref. 1-10,000%/sec. Thereafter the stretched membrane is thermally set for 0.1sec or more at temp. of cold stretching temp.-Tm at a stretching magnification rate of 0.9-2.

Inventors

• 👤 Takanori Anazawa
• 👤 穴沢　孝典
• 👤 Kazuo Hasumi
• 👤 蓮見　和夫
• 👤 Yoshiyuki Ono
• 👤 善之 小野

Bibliographic Details