Porous membrane, membrane module, water treatment device, and method for manufacturing porous membrane

Patent metadata

Field	Value
Publication number	US-11071954-B2
Application number	US-201916569420-A
Country	US
Kind code	B2
Filing date	Sep 12, 2019
Priority date	Mar 27, 2017
Publication date	Jul 27, 2021
Grant date	Jul 27, 2021

Abstract

Provided is a porous membrane that can be manufactured in uncomplicated steps, has high hydrophilicity and water permeability, and exhibits excellent anti-fouling properties when used in a membrane bioreactor method (MBR method). The porous membrane of the present invention is a porous membrane containing polymer (A) and polymer (B), wherein the polymer (A) is a membrane-forming polymer, the polymer (B) is a polymer having a unit (b1) represented by formula (1) and a unit (b2) based on hydroxyl group-containing (meth)acrylate, and the concentration (mass %) of the unit (b1) is equal to or higher than the concentration (mass %) of the unit (b2) in the porous membrane.

First claim

The invention claimed is:

1. A porous membrane, comprising polymer (A) and polymer (B), wherein
the polymer (A) is a membrane-forming polymer,
the polymer (B) is a polymer comprising
a unit (b1) represented by formula (1) below:

wherein, in formula (1), s is 2 or 3 and t is an integer of 0 to 2,

a unit (b2) based on hydroxyl group-containing (meth)acrylate, and
a unit (b3) comprising a group represented by formula (2) below:

wherein, in formula (2), R 1 to R n each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, or a heterocyclic group, X 1 to X n each independently represent a hydrogen atom or a methyl group, and n is an integer of 3 to 10,000, and

the concentration (mass %) of the unit (b1) is equal to or higher than the concentration (mass %) of the unit (b2) in the porous membrane.

2. The porous membrane according to claim 1 ,
wherein the unit (b1) is based on 2-methoxyethyl acrylate.

3. The porous membrane according to claim 1 , which is a porous membrane that filtrates water to be treated to turn the water to be treated into treated water, and which comprises:
a plurality of porous layers comprising the polymer (A),
wherein, among the plurality of porous layers, the concentration (mass %) of the polymer (B) among all polymers comprised in at least an outermost layer of the porous membrane on a side of the water to be treated is higher than the concentration (mass %) of the polymer (B) among all the polymers comprised in the porous layers other than the outermost layer.

4. The porous membrane according to claim 1 , wherein a for of the membrane is a hollow fiber membrane.

5. The porous membrane according to claim 1 , further comprising a support.

6. A membrane module, comprising:
the porous membrane according to claim 1 .

7. A water treatment device, comprising:
the membrane module according to claim 6 .

8. A method for manufacturing a porous membrane, the method comprising manufacturing a porous membrane precursor using a membrane-manufacturing stock solution comprising a polymer (A), a polymer (B), and a polymer (C) comprising a unit based on vinyl pyrrolidone, and removing some or all of the entire polymer (C) from the porous membrane precursor, wherein
the polymer (A) is a membrane-forming polymer,
the polymer (B) is a polymer comprising
a unit (b1) represented by formula (1) below:

wherein, in formula (1), s is 2 or 3, and t is an integer of 0 to 2,

a unit (b2) based on hydroxyl group-containing (meth)acrylate, and
a unit (b3) comprising a group represented by formula (2) below:

wherein, in formula (2), R 1 to R n each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, or a heterocyclic group, X 1 to X n each independently represent a hydrogen atom or a methyl group, and n is an integer of 3 to 10,000, and

the concentration (mass %) of the unit (b1) is equal to or higher than the concentration (mass %) of the unit (b2) in the membrane-manufacturing stock solution.

9. The method according to claim 8 , wherein the unit (b1) is based on 2-methoxyethyl acrylate.

10. A method for manufacturing a porous membrane which filtrates water to be treated to turn the water to be treated into treated water, the porous membrane comprising a plurality of porous layers comprising a polymer (A), the method comprising manufacturing a porous membrane precursor comprising a plurality of porous precursor layers each corresponding to a plurality of membrane-manufacturing stock solutions comprising the polymer (A) and a polymer (C) which comprises a unit based on vinyl pyrrolidone using the plurality of membrane-manufacturing stock solutions, and removing some or all of the polymer (C) from the porous membrane precursor,
wherein, among the plurality of membrane-manufacturing stock solutions, a membrane-manufacturing stock solution at least associated with an outermost layer of the porous membrane on a side of the water to be treated further comprises a polymer (B), and wherein the concentration (mass %) of the polymer (B) among all polymers comprised in the membrane-manufacturing stock solution associated with the outermost layer is higher than the concentration (mass %) of the polymer (B) among all polymers comprised in a membrane-manufacturing stock solution associated with a porous layer other than the outermost layer, and
the polymer (B) is a polymer comprising
a unit (b1) represented by formula (1) below:

wherein, in formula (1), s is 2 or 3 and t is an integer of 0 to 2,

a unit (b2) based on hydroxyl group-containing (meth)acrylate, and
a unit (b3) comprising a group represented by formula (2) below:

wherein, in formula (2), R 1 to R n each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, or a heterocyclic group, X 1 to X n each independently represent a hydrogen atom or a methyl group, and n is an integer of 3 to 10,000.

11. The porous membrane according to claim 1 , wherein a concentration of the unit (b3) among all the units constituting the polymer (B) is 10 to 45 mass %.

12. The porous membrane according to claim 1 , which comprises an outermost layer wherein a concentration of the polymer (B) is 0.1 to 40 mass %.

13. The porous membrane according to claim 1 , which has a bubble point pressure of 100 kPa or higher, and an HP value of 0.7 to 0.9.

14. The porous membrane according to claim 1 , which has a bubble point pressure of 130 to 225 kPa, and an HP value of 0.7 to 0.9.

15. The method according to claim 8 , wherein the porous membrane has a bubble point pressure of 100 kPa or higher, and an HP value of 0.7 to 0.9.

16. The method according to claim 8 , wherein the porous membrane has a bubble point pressure of 130 to 225 kPa, and an HP value of 0.7 to 0.9.

17. The method according to claim 10 , wherein the porous membrane has a bubble point pressure of 100 kPa or higher, and an HP value of 0.7 to 0.9.

18. The method for manufacturing a porous membrane according to claim 10 , wherein the porous membrane has a bubble point pressure of 130 to 225 kPa, and an HP value of 0.7 to 0.9.

Assignees

• Mitsubishi Chem Corp

Inventors

• Hikita Shingo
• Teramachi Masashi
• Fujii Yuuki
• Kubo Megumi
• SHINODA Ami
• Fukuta Hiroki
• Mori Seiichiro

Classifications

• B01D2325/0283

  Pore size · CPC title

• B01D67/0011

  Casting solutions therefor · CPC title

• B01D69/1071

  Woven, non-woven or net mesh · CPC title

• B01D71/441

  Polyvinylpyrrolidone · CPC title

• B01D71/401

  Polymers based on the polymerisation of acrylic acid, e.g. polyacrylate · CPC title