The purpose of the present invention is to provide: a separation film that consists primarily of a cellulose ester and has a high membrane strength and a high elongation degree; and a production method therefor. Provided is a separation film which has a structure comprising a cellulose ester phase and pores, wherein the average pore diameter R is 0.001-6 μm, the value obtained from the expression: breaking strength (MPa)÷(100−porosity (%))×100 is 40 or greater, and the elongation degree is 10% or greater.

The present disclosure provides a hydrophilic, integrally asymmetric, semi-permeable hollow-fiber membrane made from a hydrophobic aromatic sulfone polymer and at least one hydrophilic polymer, the membrane comprising an inner surface facing towards its lumen, an outer surface facing outwards and an intermediate wall having a wall thickness and comprising an open-pore separating layer and an supporting layer having an asymmetric, sponge-like structure without finger pores, wherein adjoining to the wall of the inner surface the hollow-fiber membrane comprises an essentially isotropic zone; after which the pore size abruptly start increasing up to a maximum, after which the pore size decrease again, then adjoining an essentially isotropic supporting layer which then is adjoined by the outer surface, wherein the separating layer has a cut-off of greater than 300 000 Daltons. The present disclosure further provides a method for producing such membranes and a use of the membranes for microfiltration purposes.

The present disclosure relates to a microporous hollow fiber filter membrane having a large inner diameter and a thin wall. The fiber can be used for sterile filtration of liquids or removal of particles from liquids. The disclosure further relates to a method for producing the membrane and a filter device comprising the membrane.

A method for processing a fluid with forward osmosis process includes providing one or more tubular membranes each including a tubular nonwoven base layer on the outside of the tubular membrane forming an outer shell of the tubular membrane and providing a lumen for feed flow; a polymer substrate layer on the lumen-side of the tubular membrane comprising three regions, including a region where the polymer substrate layer is partially intruded into the tubular base layer, a region with an open macrovoid structure and a region with an asymmetrical foamy layer, where the partially intruded region forms an intermediate layer; and a functional top layer on the polymer substrate layer. The tubular base layer comprises a longitudinal weld. The method includes providing the feed flow through the lumen and providing a draw solution on the outer shell side of the tubular membrane; and processing the feed flow with the membrane.

Provided is a method including the steps of producing a melt-kneaded product and discharging the melt-kneaded product. In the step of producing a melt-kneaded product, a thermoplastic resin, a non-solvent and an inorganic compound are mixed and melt-kneaded, wherein the non-solvent does not uniformly dissolve the thermoplastic resin of one-quarter mass at a boiling point or 250° C., whichever is lower.

There is provided a hollow fiber membrane for vacuum membrane distillation having a maximum tensile strength of a ≥3.5 MPa and a liquid entry pressure (LEP) of ≥3.0 bar, wherein the hollow fiber membrane is a single layer hollow fiber membrane comprising a wall with a thickness of ≤150 μm and a cross-section comprising two open cell layers with an array of interconnected pores and a macrovoid layer between the two open cell layers. The hollow fiber has improved mechanical strength and vacuum membrane distillation flux.

Hydrophobic hollow-fiber membrane made from a vinylidene fluoride polymer with a wall and a wall thickness, an outer surface on its outer side, an inner surface on its inner side and facing its lumen and adjacent to the inner surface a supporting layer having a structure that is substantially isotropic across the wall thickness, the supporting layer extending over at least 80% of the wall thickness and comprising pores having an average diameter of less than 1 m, and wherein the hollow-fiber membrane has pores on its outer surface and on its inner surface, characterized in that the vinylidene fluoride polymer has a weight-average molecular weight M.sub.W in the range from 550 000 to 700 000 daltons and a polydispersivity greater than 3.0; the pores in the outer and in the inner surface are formed like islands and have a maximum ratio of their longitudinal extension to the transverse extension of 10; the porosity lies in the range from 50 to 90 vol. %, the wall thickness in the range from 50 to 300 m, and the diameter of the lumen in the range from 100 to 500 m; and the hollow-fiber membrane has a maximum separating pore diameter d.sub.max in the range from 0.3 to 0.7 m, determined according to the bubble point method.

Hydrophobic flat membrane made from a vinylidene fluoride polymer with a wall, a first surface, and a second surface. The membrane has on its first surface a network structure with open pores and on its second surface a continuous skin in which pores are formed, and adjacent to the skin of the second surface a supporting layer with an isotropic pore structure across the wall thickness, wherein the supporting layer extends over at least 80% of the wall thickness and wherein the pores of the supporting layer have an average diameter of less than 1 m. The weight average of the molecular weight M.sub.W of the vinylidene fluoride polymer lies in the range from 300 000 to 500 000 daltons, and the polydispersivity M.sub.W/M.sub.N is greater than 5.5. The pores in the skin of the second surface have a closed perimeter in the plane of the skin and an average ratio of the extension in the direction of the longest axis thereof to the extension in the direction of the shortest axis thereof of at most 5. The pores in the first surface and second surface have an essentially isotropic distribution of their orientation. The porosity of the membrane lies in the range from 50 to 90 vol. % and the wall thickness in the range from 50 to 300 m. The membrane has a maximum separating pore diameter d.sub.max in the range from 0.05 to 1.5 m.

Providing a membrane-forming solution suitable for producing a separation membrane such as a hollow fiber membrane and a flat membrane. A membrane-forming solution including triacetylcellulose having an acetyl group substitution degree of 2.7 or higher, a good solvent for thermally induced phase separation and a poor solvent for thermally induced phase separation, wherein the good solvent is capable of heat-dissolving the triacetylcellulose (at a solid content concentration of 25 mass %), and the poor solvent is incapable of dissolving the triacetylcellulose up to the heat dissolution temperature of the good solvent, wherein both the good solvent and the poor solvent are included so as to enable phase separation of the heat-dissolved triacetylcellulose solution while the heat-dissolved triacetylcellulose solution is cooled to room temperature (from 20 to 30 C.), and wherein a mixing ratio in a total amount of the good solvent and the poor solvent is from 5 to 40 mass % of the good solvent and from 60 to 95 mass % of the poor solvent.

The present invention relates to a hollow fiber membrane including, sequentially from the center: a first layer having a high-density sponge structure including pores with a size of 1 nm or less; a second layer including a finger-shaped structure; and a third layer having a low-density sponge structure including pores with a size of 10 to 1,000 m, and to a method for producing the hollow fiber membrane.