Patent ID: 9617683
Date: 2017-04-11
CPC Classifications: B01D,D06M

Claim:
1. A separation membrane being substantially free from curling comprising an elongated fluid-permeable base and a first separation layer formed over substantially most of the base, wherein the base comprises any one of a woven fabric, a non-woven fabric or a net, wherein the first separation layer composed of a polymer material is a single layer being formed over the base while infiltrating to a certain depth of the base or through to the reverse side of the base, wherein the first separation layer includes: wherein a separation-layer-lacking portion, at which only the base is present while the first separation layer is absent, exists between each widthwise outer end of the thinner portion and each widthwise end of the base, said widthwise ends perpendicular to the longitudinal direction of the base, wherein a width of the thinner portion positioned on an outside of each widthwise end of the predetermined thickness portion is 0.1 to 10% of a width of the elongated fluid-permeable base, and wherein a width of the separation-layer-lacking portion which exists between the widthwise outer end of the thinner portion and the widthwise end of the elongated fluid permeable base is 0.1 to 10% of the width of the elongated fluid-permeable base.