| 摘要 |
PURPOSE:To reduce the diameter, to increase the amt. of water to be permeated, to permeate low molecular substances, and to exclude high molecular substances by forming a particle binding layer having 0.01-2mum thickness at the next to the surface of an EVA copolymer hollow yarn membrane with a dense active layer on the surface. CONSTITUTION:An ethylene-vinyl alcohol copolymer is dissolved in a polar org. solvent to obtain a spinning soln. The soln. is spinned while introducing a coagulable liq. into the hollow part, and coagulated in a gaseous atmosphere under 3-30 times draft. When the coagulation temp. at this time is expressed as T and the polymer concn. as C, the relational expression, -15<=T<=(C/4)+10, must be satisfied at 15<=C<=40. Consequently, a three-layered EVA hollow yarn membrane consisting of a dense active layer 1 on at least one of the membrane surfaces, an internal binding layer 3 of particles 2 having 0.01-2mum particle diameter at the next to both surfaces, and further an internal homogeneous layer 4 wherein a particulate structure is not substantially recognized can be obtained.
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