Porous hollow fiber membrane, method for producing porous hollow fiber membrane and filtration method
AssigneeAsahi Kasei Kabushik Kasha
InventorDaisuke Okamura
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Abstract
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.
Claims22
A method for producing a porous hollow fiber membrane, comprising the steps of:
- mixing and melt-kneading a thermoplastic resin, a non-solvent that does not uniformly dissolve the thermoplastic resin of one-quarter mass at a boiling point or 250° C., whichever is lower, and an inorganic compound to produce a kneaded product;
- and
- discharging the kneaded product.
A porous hollow fiber membrane containing a thermoplastic resin, a solvent and an inorganic compound, wherein the solvent is a non-solvent that does not uniformly dissolve the thermoplastic resin of one-quarter mass at a boiling point or 250° C., whichever is lower.
A porous hollow fiber membrane containing a thermoplastic resin, a solvent and an inorganic compound, wherein
- the thermoplastic resin is a thermoplastic resin that contains, in its molecule, at least one selected from vinylidene fluoride, chlorotrifluoroethylene, tetrafluoroethylene, hexafluoropropylene and vinyl fluoride;
- the solvent is a non-solvent that does not uniformly dissolve the thermoplastic resin of one-quarter mass at a boiling point or 250° C., whichever is lower;
- and
- a sum of areas of resin portions each having an area of 1 μm2 or less is 70% or more to a total area of the resin portions in each region of a total of four fields of view including, in an SEM image of a membrane cross-section in a membrane thickness direction orthogonal to an inner surface of the porous hollow fiber membrane, a field of view including the inner surface, a field of view including an outer surface of the porous hollow fiber membrane and two fields of view taken at equal intervals between these fields of view.
A porous hollow fiber membrane containing a thermoplastic resin, a solvent and an inorganic compound, wherein
- the thermoplastic resin is a thermoplastic resin that contains, in its molecule, at least one selected from vinylidene fluoride, chlorotrifluoroethylene, tetrafluoroethylene, hexafluoropropylene and vinyl fluoride;
- the solvent is a non-solvent that does not uniformly dissolve the thermoplastic resin of one-quarter mass at a boiling point or 250° C., whichever is lower;
- and
- a sum of areas of resin portions each having an area of 10 μm2 or more is 15% or less to a total area of the resin portions in each region of a total of four fields of view including, in an SEM image of a membrane cross-section in a membrane thickness direction orthogonal to an inner surface of the porous hollow fiber membrane, a field of view including the inner surface, a field of view including an outer surface of the porous hollow fiber membrane and two fields of view taken at equal intervals between these fields of view.
A porous hollow fiber membrane containing a thermoplastic resin, a solvent and an inorganic compound, wherein
- the thermoplastic resin is one of ethylene-tetrafluoroethylene, ethylene-monochlorotrifluoroethylene and vinylidene fluoride, ethylene, trifluoroethylene copolymers;
- and
- a sum of areas of resin portions each having an area of 1 μm2 or less is 70% or more to a total area of the resin portions in each region of a total of four fields of view including, in an SEM image of a membrane cross-section in a membrane thickness direction orthogonal to an inner surface of the porous hollow fiber membrane, a field of view including the inner surface, a field of view including an outer surface of the porous hollow fiber membrane and two fields of view taken at equal intervals between these fields of view.
A porous hollow fiber membrane containing a thermoplastic resin, a solvent and an inorganic compound, wherein
- the thermoplastic resin is one of ethylene-tetrafluoroethylene, ethylene-monochlorotrifluoroethylene and vinylidene fluoride, ethylene, trifluoroethylene copolymers;
- and
- a sum of areas of resin portions each having an area of 10 μm2 or more is 15% or less to a total area of the resin portions in each region of a total of four fields of view including, in an SEM image of a membrane cross-section in a membrane thickness direction orthogonal to an inner surface of the porous hollow fiber membrane, a field of view including the inner surface, a field of view including an outer surface of the porous hollow fiber membrane and two fields of view taken at equal intervals between these fields of view.
Dependencies are inferred from the claim text.