WO2020008820A1

WO2020008820A1 - Hydrophilic composite membrane, hydrophilic porous membrane, and hydrophilic resin composition

Info

Publication number: WO2020008820A1
Application number: PCT/JP2019/023159
Authority: WO
Inventors: 櫻井　博志; 西川　聡; 優長尾
Original assignee: 帝人株式会社
Priority date: 2018-07-05
Filing date: 2019-06-11
Publication date: 2020-01-09
Also published as: TW202006033A

Abstract

Provided is a hydrophilic composite membrane comprising a porous substrate and at least one hydrophilic material, among a first hydrophilic material and a second hydrophilic material, present in the pores of the porous substrate. The first hydrophilic material contains a water-insoluble copolymer having a vinyl alcohol unit and an acrylic monomer unit. The second hydrophilic material contains, in a compatible state: a water-insoluble copolymer having a vinyl alcohol unit and an acrylic monomer unit; and a polyvinylidene fluoride-based resin. Also provided is a hydrophilic porous membrane containing, in a compatible state: a polyvinylidene fluoride-based resin; and a water-insoluble copolymer having a vinyl alcohol unit and an acrylic monomer unit. Also provided is a hydrophilic resin composition containing, in a compatible state: a polyvinylidene fluoride-based resin; and a water-insoluble copolymer having a vinyl alcohol unit and an acrylic monomer unit.

Description

Hydrophilic composite membrane, hydrophilic porous membrane and hydrophilic resin composition

The present invention relates to a hydrophilic composite membrane, a hydrophilic porous membrane, and a hydrophilic resin composition.

Patent Document 1 discloses a hydrophilic polyvinylidene fluoride porous membrane in which after a hydrophobic polyvinylidene fluoride porous membrane is wetted with a solvent, the membrane is brought into contact with a solution containing polyvinylpyrrolidone and a polymerization initiator to crosslink polyvinylpyrrolidone. A method for manufacturing a membrane is disclosed.

Patent Literature 2 discloses a hydrophilic porous fluororesin membrane in which a porous fluororesin sheet is coated with a polymer compound having a hydroxyl group, the polymer compound is reacted with an aliphatic dialdehyde, and further reacted with formaldehyde. A manufacturing method is disclosed.

Patent Document 3 discloses a hydrophilized porous membrane obtained by dispersing an organized clay, which has been organized with a hydrophilic compound, in a hydrophobic polymer.

Patent Document 4 discloses a hydrophilized porous membrane containing a decomposed product of a hydrophilizing agent that generates a hydrophilic chemical species by a decomposition reaction, and a polyvinylidene fluoride-based resin.

JP-A-11-302438 JP 2018-28011 A JP 2004-352824 A JP 2005-296846 A

親水 The hydrophilic porous membranes disclosed in Patent Documents 1 to 4 have room for improvement in water permeability.

The first embodiment of the present disclosure has been made under the above situation.
A first embodiment of the present disclosure aims to provide a hydrophilic composite membrane having excellent water permeability, and has an object to solve the problem.

親水 The hydrophilic porous membrane disclosed in Patent Document 1 or Patent Document 2 is a porous membrane in which a hydrophobic porous membrane is coated with a hydrophilic component, and there is a concern that the hydrophilic component may be detached from the membrane. In the hydrophilic porous membrane disclosed in Patent Document 3, there is a concern that the organized clay is detached from the membrane or the hydrophilic compound is detached from the organized clay. In the hydrophilic porous membrane disclosed in Patent Document 4, there is a concern that decomposed products of the hydrophilizing agent dispersed and contained in the membrane may be detached from the membrane.

The second embodiment of the present disclosure has been made under the above situation.
A second embodiment of the present disclosure aims to provide a hydrophilic porous membrane in which desorption of a hydrophilic component is unlikely to occur, and has an object to solve the problem.
In addition, a second embodiment of the present disclosure aims to provide a hydrophilic resin composition in which detachment of a hydrophilic component is unlikely to occur, and has an object to solve the problem.

具体 Specific means for solving the above problems include the following aspects.

[1] A hydrophilic substrate comprising: a porous substrate; and at least one of a first hydrophilic material and a second hydrophilic material described below, which are present in pores of the porous substrate. Composite membrane.
First hydrophilic material: a hydrophilic material containing a water-insoluble copolymer having a vinyl alcohol unit and an acrylic monomer unit.
Second hydrophilic material: a hydrophilic material containing a water-insoluble copolymer having a vinyl alcohol unit and an acrylic monomer unit and a polyvinylidene fluoride-based resin in a compatible state.
[2] The hydrophilic composite membrane according to [1], wherein the porous substrate has an average pore size of 1 nm to 4000 nm.
[3] The hydrophilic composite membrane according to [1] or [2], wherein the porous substrate has a water contact angle of 85 ° to 130 ° on one surface or both surfaces.
[4] The hydrophilic composite film according to any one of [1] to [3], wherein a mass ratio of the vinyl alcohol unit in the water-insoluble copolymer is from 40% by mass to 90% by mass.
[5] The hydrophilic composite film according to any one of [1] to [4], wherein the acrylic monomer unit includes at least one selected from the group consisting of a methacrylate unit and an acrylate unit.
[6] The mass ratio of the water-insoluble copolymer and the polyvinylidene fluoride resin (the water-insoluble copolymer: the polyvinylidene fluoride resin) contained in the second hydrophilic material is from 5:95 to The hydrophilic composite membrane according to any one of [1] to [5], wherein the ratio is 60:40.
[7] A hydrophilic coating layer provided on one surface or both surfaces of the porous substrate, wherein the hydrophilic coating layer is at least one of a first hydrophilic coating layer and a second hydrophilic coating layer described below. The hydrophilic composite membrane according to any one of [1] to [6], wherein
First hydrophilic coating layer: a hydrophilic coating layer containing a water-insoluble copolymer having a vinyl alcohol unit and an acrylic monomer unit.
Second hydrophilic coating layer: a hydrophilic coating layer containing a water-insoluble copolymer having a vinyl alcohol unit and an acrylic monomer unit and a polyvinylidene fluoride resin in a state of being compatible with each other.
[8] The hydrophilic composite membrane according to [7], wherein the first hydrophilic coating layer or the second hydrophilic coating layer is a porous layer.
[9] The hydrophilic composite membrane according to any one of [1] to [8], wherein the porous substrate is a polyolefin microporous membrane.

[10] A hydrophilic porous membrane containing a polyvinylidene fluoride resin and a water-insoluble copolymer having a vinyl alcohol unit and an acrylic monomer unit in a compatible state.
[11] The hydrophilic porous membrane according to [10], wherein the mass ratio of the vinyl alcohol unit in the water-insoluble copolymer is from 40% by mass to 90% by mass.
[12] The hydrophilic porous membrane according to [10] or [11], wherein the acrylic monomer unit includes at least one selected from the group consisting of a methacrylate unit and an acrylate unit.
[13] The mass ratio of the polyvinylidene fluoride resin to the water-insoluble copolymer (the polyvinylidene fluoride resin: the water-insoluble copolymer) contained in the hydrophilic porous membrane is 40:60 to 95: 5. The hydrophilic porous membrane according to any one of [10] to [12], which is 5.
[14] A hydrophilic resin composition containing a polyvinylidene fluoride resin and a water-insoluble copolymer having a vinyl alcohol unit and an acrylic monomer unit in a compatible state.
[15] The hydrophilic resin composition according to [14], wherein a mass ratio of the vinyl alcohol unit in the water-insoluble copolymer is from 40% by mass to 90% by mass.
[16] The hydrophilic resin composition according to [14] or [15], wherein the acrylic monomer unit includes at least one selected from the group consisting of a methacrylate unit and an acrylate unit.
[17] The mass ratio of the polyvinylidene fluoride resin to the water-insoluble copolymer (the polyvinylidene fluoride resin: the water-insoluble copolymer) contained in the hydrophilic resin composition is 40:60 to 95. : 5 is the hydrophilic resin composition according to any one of [14] to [16].

According to the first embodiment of the present disclosure, a hydrophilic composite membrane having excellent water permeability is provided.

According to the second embodiment of the present disclosure, there is provided a hydrophilic porous membrane in which desorption of a hydrophilic component is less likely to occur.
Further, according to the second embodiment of the present disclosure, there is provided a hydrophilic resin composition in which detachment of a hydrophilic component is less likely to occur.

Hereinafter, embodiments of the present disclosure will be described. These descriptions and examples illustrate the embodiments, and do not limit the scope of the embodiments.

において In the present disclosure, a numerical range indicated by using “to” indicates a range including numerical values described before and after “to” as a minimum value and a maximum value, respectively.

In the numerical ranges described in stages in the present disclosure, the upper limit or lower limit described in one numerical range may be replaced with the upper limit or lower limit of the numerical range described in other stages. . Further, in the numerical range described in the present disclosure, the upper limit or the lower limit of the numerical range may be replaced with the value shown in the embodiment.

において In the present disclosure, the term “step” is included in the term, not only in an independent step but also in a case where the intended purpose of the step is achieved even if it cannot be clearly distinguished from other steps.

において In the present disclosure, each component may include a plurality of corresponding substances. In the present disclosure, when referring to the amount of each component in the composition, when a plurality of types of substances corresponding to each component are present in the composition, unless otherwise specified, the plurality of types of the components present in the composition are not specified. Means the total amount of the substance.

において In the present disclosure, “(meth) acryl” means at least one of acryl and methacryl, and “(meth) acrylate” means at least one of acrylate and methacrylate.

において In the present disclosure, the “monomer unit” is a constituent element of a polymer, and means a constituent element obtained by polymerizing a monomer.

<First embodiment: hydrophilic composite membrane>
The hydrophilic composite membrane of the present disclosure is a porous substrate, and present in the pores of the porous substrate, a hydrophilic material of at least one of a first hydrophilic material and a second hydrophilic material described below. And

First hydrophilic material: a hydrophilic material containing a water-insoluble copolymer having a vinyl alcohol unit and an acrylic monomer unit.
Second hydrophilic material: a hydrophilic material containing a water-insoluble copolymer having a vinyl alcohol unit and an acrylic monomer unit and a polyvinylidene fluoride-based resin in a compatible state.

において In the present disclosure, a water-insoluble copolymer having a vinyl alcohol unit and an acrylic monomer unit is referred to as a water-insoluble copolymer VA.

The water-insoluble copolymer VA exhibits hydrophilicity due to the hydroxyl group of the vinyl alcohol unit. The first hydrophilic material and the second hydrophilic material exhibit hydrophilicity by containing the water-insoluble copolymer VA which is hydrophilic. Since the water-insoluble copolymer VA is water-insoluble, it does not easily elute from the first hydrophilic material and the second hydrophilic material into the aqueous medium.

The hydrophilic composite membrane of the present disclosure shows excellent hydrophilicity due to the presence of at least one of the first hydrophilic material and the second hydrophilic material that are hydrophilic in the pores of the porous substrate, Excellent water permeability.

In the hydrophilic composite membrane of the present disclosure, the contact angle of water measured on one or both surfaces under the following measurement conditions is preferably 60 degrees or less, and the smaller the contact angle of water, the more preferable. The hydrophilic composite membrane of the present disclosure, on one or both sides, when trying to measure the contact angle of water under the following measurement conditions, it should be so hydrophilic that water droplets penetrate inside the composite membrane and become unmeasurable. Is more preferred.
Here, the contact angle of water is a value measured by the following measuring method. After leaving the composite membrane in an environment of a temperature of 25 ° C. and a relative humidity of 60% for 24 hours or more to control the humidity, under the environment of the same temperature and humidity, a drop of 1 μL of ion-exchanged water was applied to the surface of the composite membrane with a syringe. Using a fully automatic contact angle meter (Kyowa Interface Science Co., Ltd., model number Drop Master DM500), the contact angle after 30 seconds is measured by the θ / 2 method.

Hereinafter, items common to the first hydrophilic material and the second hydrophilic material will be collectively described as hydrophilic materials.

Examples of the form of the hydrophilic composite membrane of the present disclosure include, for example, a form in which a part or all of the wall surfaces of pores of a porous substrate are covered with a hydrophilic material, a part of pores of a porous substrate, Examples include a form in which the whole is filled with a hydrophilic material, and a form in which a part of the wall surface of the pores of the porous substrate is covered with the hydrophilic material and a part of the pores is filled with the hydrophilic material.

において In the hydrophilic composite membrane of the present disclosure, when the pores of the porous base material are filled with a hydrophilic material, the hydrophilic material preferably has a porous structure. Here, the porous structure means a structure having a large number of micropores inside, these micropores are connected, and a gas or liquid can pass from one side to the other side. .

The hydrophilic composite membrane of the present disclosure is used, for example, for the purpose of separation, purification, concentration, fractionation, and the like of a substance dispersed or dissolved in an aqueous medium.
Applications of the hydrophilic composite membrane of the present disclosure include, for example, water purification, sanitization, desalination of seawater, artificial dialysis, pharmaceutical production, food production, protein separation, and the like.

膜厚 The thickness, pore size, and porosity of the hydrophilic composite membrane of the present disclosure are not particularly limited, and may be selected according to the application, structure, or type.

表面 The surface of the hydrophilic composite membrane of the present disclosure may be subjected to various surface treatments. Examples of the surface treatment include corona treatment, plasma treatment, flame treatment, and ultraviolet irradiation treatment.

[Porous substrate]
In the present disclosure, the porous substrate means a substrate having pores or voids therein. Examples of such a substrate include a microporous membrane; a porous sheet made of a fibrous material, such as a nonwoven fabric or paper; As the porous substrate, a microporous film is preferable from the viewpoint of thinning and strength of the hydrophilic composite film. A microporous membrane is a membrane that has a large number of micropores inside and has a structure in which these micropores are connected, so that gas or liquid can pass from one surface to the other. I do.

材料 The material of the porous substrate may be either an organic material or an inorganic material.

The porous substrate may be either hydrophilic or hydrophobic. The hydrophilic composite membrane of the present disclosure exhibits hydrophilicity even when the porous base material is hydrophobic, because the hydrophilic material is present in the pores of the porous base material, and is excellent in water permeability.

One embodiment of the porous substrate includes a porous substrate having an average pore size of 1 nm to 4000 nm. Although a porous substrate having an average pore size of 4000 nm or less does not easily show water permeability, the hydrophilic composite membrane of the present disclosure has a hydrophilic material in pores of the porous substrate, so that the average Even if the pore size is 4000 nm or less, water permeability is easily exhibited.
On the other hand, the average pore diameter of the porous substrate is preferably 1 nm or more, more preferably 10 nm or more, from the viewpoint of arranging the hydrophilic material in the pores of the porous substrate.

The average pore size of the porous substrate was determined by using a porous substrate having neither the first hydrophilic material nor the second hydrophilic material in the pores as a sample, and using a perm porometer to determine ASTM E1294-89. Is a value obtained by the measurement method described above.

一つ One embodiment of the porous substrate includes a porous substrate having a water contact angle of 85 to 130 degrees on one or both surfaces. Although the porous substrate is hardly wetted by water and does not easily show water permeability, the hydrophilic composite membrane of the present disclosure is a porous substrate because a hydrophilic material is present in pores of the porous substrate. Also easily develop water permeability.

The contact angle of water on the surface of the porous substrate is measured by the following measurement method using a porous substrate having neither the first hydrophilic material nor the second hydrophilic material in the pores as a sample. Physical properties.
After leaving the porous substrate in an environment of a temperature of 25 ° C. and a relative humidity of 60% for 24 hours or more to control the humidity, 1 μL of ion exchange is performed on the surface of the porous substrate with a syringe under the same temperature and humidity environment. Drops of water are dropped, and the contact angle after 30 seconds is measured by a θ / 2 method using a fully automatic contact angle meter (Kyowa Interface Science Co., Ltd., model number Drop Master DM500).

厚 The thickness of the porous substrate is not particularly limited, but is preferably 1 μm to 100 μm from the viewpoint of easiness of disposing the hydrophilic material in the pores of the porous substrate.

微 One embodiment of the porous substrate is a microporous membrane containing a polyolefin such as polyethylene or polypropylene (referred to as a polyolefin microporous membrane in the present disclosure).

The microporous polyolefin membrane is preferably a microporous membrane containing polypropylene, from the viewpoint of having heat resistance that does not easily break when exposed to high temperatures.

Examples of the microporous polyolefin membrane include a microporous polyolefin membrane having a laminated structure of two or more layers, at least one layer containing polyethylene, and at least one layer containing polypropylene.

ポリ The polyolefin contained in the microporous polyolefin membrane is preferably a polyolefin having a weight average molecular weight (Mw) of 100,000 to 5,000,000. When the Mw of the polyolefin is 100,000 or more, sufficient mechanical properties can be imparted to the microporous membrane. When the Mw of the polyolefin is 5,000,000 or less, it is easy to form a microporous film.

として One embodiment of the porous substrate is a porous sheet made of a fibrous material. Examples of the fibrous porous sheet include polyesters such as polyethylene terephthalate; polyolefins such as polyethylene and polypropylene; and heat resistant materials such as wholly aromatic polyamide, polyamideimide, polyimide, polyethersulfone, polysulfone, polyetherketone, and polyetherimide. Porous sheets such as nonwoven fabric and paper made of fibrous materials such as resin; cellulose;

(4) The surface of the porous substrate may be subjected to various surface treatments for the purpose of improving the wettability of a coating liquid for disposing the hydrophilic material in the pores of the porous substrate. Examples of the surface treatment include corona treatment, plasma treatment, flame treatment, and ultraviolet irradiation treatment.

[Hydrophilic material]
The first hydrophilic material is a hydrophilic material containing a water-insoluble copolymer having a vinyl alcohol unit and an acrylic monomer unit. In the present disclosure, the first hydrophilic material does not include the second hydrophilic material.

The first hydrophilic material exhibits hydrophilicity by containing the water-insoluble copolymer VA.

The second hydrophilic material is a hydrophilic material containing the water-insoluble copolymer VA and the polyvinylidene fluoride-based resin in a compatible state.

The second hydrophilic material contains the water-insoluble copolymer VA and the polyvinylidene fluoride-based resin in a compatible state, so that the second hydrophilic material exhibits high uniformity and hydrophilicity throughout the second hydrophilic material. .

The second hydrophilic material contains the water-insoluble copolymer VA and the polyvinylidene fluoride-based resin in a compatible state, so that the water-insoluble copolymer VA, which is a hydrophilic component, becomes second hydrophilic. Difficult to detach from conductive materials.

The second hydrophilic material is excellent in heat resistance, solvent insolubility, chemical resistance and mechanical strength by containing polyvinylidene fluoride resin. Therefore, the hydrophilic composite membrane of the present disclosure having the second hydrophilic material in the pores of the porous substrate has excellent heat resistance, solvent insolubility, chemical resistance, and mechanical strength.

In the present disclosure, the state in which a plurality of types of resins contained in the material present in the pores of the porous base material are compatible means that the material present in the pores of the porous base material is subjected to transmission electron microscopy. When observed at a resolution of 0.2 nm and a magnification of 30,000 times, it means that no discontinuity of the resin phase is observed.

[Water-insoluble copolymer VA]
The first hydrophilic material and the second hydrophilic material contain a water-insoluble copolymer VA. The water-insoluble copolymer VA has at least a vinyl alcohol unit and an acrylic monomer unit, and is water-insoluble.

において In the present disclosure, the term “water-insoluble” for a copolymer having a vinyl alcohol unit and an acrylic monomer unit means that the solubility is 3 g / 100 g water or less. Solubility means the mass soluble in 100 g of water at 20 ° C. at 1 atm.

Examples of the water-insoluble copolymer VA include a copolymer obtained by saponifying a copolymer of vinyl acetate and an acrylic monomer, and a copolymer obtained by polymerizing an acrylic monomer on partially saponified polyvinyl alcohol.

When the water-insoluble copolymer VA is a copolymer obtained by polymerizing an acrylic monomer on partially saponified polyvinyl alcohol, the degree of polymerization of the partially saponified polyvinyl alcohol is not particularly limited, but is 300 to 800. Is preferred.

When the water-insoluble copolymer VA is a copolymer obtained by polymerizing an acrylic monomer on partially saponified polyvinyl alcohol, the degree of saponification of the partially saponified polyvinyl alcohol is not particularly limited, but may be 55 mol. % To 90 mol% is preferred. When the degree of saponification of the partially saponified polyvinyl alcohol is 55 mol% or more, the hydrophilicity of the water-insoluble copolymer VA is higher. In this respect, the degree of saponification of the partially saponified polyvinyl alcohol is more preferably equal to or greater than 60 mol%, and still more preferably equal to or greater than 65 mol%. On the other hand, when the degree of saponification of the partially saponified polyvinyl alcohol is 90 mol% or less, the compatibility of the water-insoluble copolymer VA with the polyvinylidene fluoride resin is higher, and the water-insoluble copolymer VA has a higher water solubility. Higher insolubility. In this respect, the saponification degree of the partially saponified polyvinyl alcohol is more preferably equal to or less than 85 mol%, and still more preferably equal to or less than 80 mol%.

質量 The mass ratio of the vinyl alcohol unit in the water-insoluble copolymer VA is preferably from 40% by mass to 90% by mass. When the mass ratio of the vinyl alcohol unit is 40% by mass or more, the hydrophilicity of the water-insoluble copolymer VA is higher. In this respect, the mass ratio of the vinyl alcohol unit is more preferably equal to or greater than 45% by mass, and still more preferably equal to or greater than 50% by mass. On the other hand, when the mass ratio of the vinyl alcohol unit is 90% by mass or less, the compatibility of the water-insoluble copolymer VA with the polyvinylidene fluoride resin is higher, and the water-insolubility of the water-insoluble copolymer VA is higher. . In this respect, the mass ratio of the vinyl alcohol unit is more preferably equal to or less than 85% by mass, and still more preferably equal to or less than 80% by mass.

アクリル The acrylic monomer constituting the acrylic monomer unit includes at least one acrylic monomer selected from the group consisting of (meth) acrylic acid, (meth) acrylate, and (meth) acrylate.

Examples of the (meth) acrylate include sodium (meth) acrylate, potassium (meth) acrylate, magnesium (meth) acrylate, and zinc (meth) acrylate.

Examples of the (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, and (meth) acrylic acid. N-hexyl acid, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, dicyclopentanyl (meth) acrylate, (meth) acrylic acid Isobornyl, 2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2- (diethylamino) ethyl (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, etc. Is mentioned.

The water-insoluble copolymer VA has higher compatibility with the polyvinylidene fluoride-based resin, and from the viewpoint of higher water-insolubility, from the group consisting of a methacrylate unit and an acrylate unit as an acrylic monomer unit. It preferably has at least one selected from the group, and more preferably has a methacrylate unit. As the (meth) acrylate, a lower alkyl ester of (meth) acrylic acid (having 1 to 4 carbon atoms in the alkyl group) is preferred, methyl methacrylate or methyl acrylate is more preferred, and methyl methacrylate is still more preferred.

質量 The mass ratio of the acrylic monomer unit in the water-insoluble copolymer VA is preferably from 10% by mass to 60% by mass. When the mass ratio of the acrylic monomer unit is 10% by mass or more, the compatibility of the water-insoluble copolymer VA with the polyvinylidene fluoride-based resin is higher, and the water-insolubility of the water-insoluble copolymer VA is higher. In this respect, the mass ratio of the acrylic monomer unit is more preferably equal to or greater than 15% by mass, and still more preferably equal to or greater than 20% by mass. On the other hand, when the mass ratio of the acrylic monomer unit is 60% by mass or less, the hydrophilicity of the water-insoluble copolymer VA is higher. In this respect, the mass ratio of the acrylic monomer unit is more preferably equal to or less than 55% by mass, more preferably equal to or less than 50% by mass, and still more preferably equal to or less than 45% by mass.

For the above reasons, the total mass ratio of the methyl methacrylate unit and the methyl acrylate unit in the water-insoluble copolymer VA is preferably from 10% by mass to 60% by mass, more preferably from 15% by mass to 55% by mass, 20 to 50% by mass is more preferable, and 20 to 45% by mass is more preferable.

As an example of a preferred embodiment of the water-insoluble copolymer VA, a vinyl alcohol unit, at least one selected from the group consisting of methacrylic ester units and acrylic ester units, and a group selected from the group consisting of methacrylic acid units and acrylic acid units And at least one of the above. As the (meth) acrylate, a lower alkyl ester of (meth) acrylic acid (having 1 to 4 carbon atoms in the alkyl group) is preferred, methyl methacrylate or methyl acrylate is more preferred, and methyl methacrylate is still more preferred. The total mass ratio of (meth) acrylate units in the water-insoluble copolymer VA of this embodiment is preferably from 10% by mass to 50% by mass, more preferably from 15% by mass to 45% by mass, and preferably from 20% by mass to 40% by mass. % Is more preferred. The total mass ratio of the (meth) acrylic acid units in the water-insoluble copolymer VA of this embodiment is preferably from 5% by mass to 30% by mass, more preferably from 5% by mass to 25% by mass.

The water-insoluble copolymer VA may have other monomer units other than the vinyl alcohol unit and the acrylic monomer unit. As other monomer units, styrene-based monomer units are preferred from the viewpoint of balancing the hydrophilicity and water-insolubility of the water-insoluble copolymer VA.

Examples of the styrene monomer include styrene, metachlorostyrene, parachlorostyrene, parafluorostyrene, paramethoxystyrene, meta-tert-butoxystyrene, para-tert-butoxystyrene, palavinyl benzoic acid, and paramethyl-α-methylstyrene. And the like. As the styrene monomer, styrene, paramethoxystyrene, and paramethyl-α-methylstyrene are preferable, and styrene is particularly preferable.

When the water-insoluble copolymer VA has a styrene-based monomer unit, the mass ratio of the styrene-based monomer in the water-insoluble copolymer VA is preferably 1% by mass to 15% by mass, more preferably 5% by mass to 10% by mass. .

質量 The mass ratio of the vinyl alcohol unit and the acrylic monomer unit in the water-insoluble copolymer VA is preferably 85% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more.

水 The water-insoluble copolymer VA contained in the hydrophilic material may be one type or two or more types.

重量 The weight average molecular weight (Mw) of the water-insoluble copolymer VA is not particularly limited, but is preferably 50,000 to 15,000,000.

In the second hydrophilic material, the content of the water-insoluble copolymer VA with respect to the total amount of the water-insoluble copolymer VA and the polyvinylidene fluoride resin is preferably 5% by mass to 60% by mass. When the content of the water-insoluble copolymer VA is 60% by mass or less, the second hydrophilic material is easily made porous when the second hydrophilic material is arranged in the pores of the porous substrate. From this viewpoint, the content of the water-insoluble copolymer VA based on the total amount of the water-insoluble copolymer VA and the polyvinylidene fluoride-based resin is more preferably 55% by mass or less, and more preferably 50% by mass or less. Is more preferably 45% by mass or less.
On the other hand, from the viewpoint of improving the hydrophilicity of the second hydrophilic material, the content of the water-insoluble copolymer VA with respect to the total amount of the water-insoluble copolymer VA and the polyvinylidene fluoride-based resin is 5% by mass or more. Preferably, it is 15% by mass or more, more preferably 25% by mass or more.

[Polyvinylidene fluoride resin]
The second hydrophilic material contains a polyvinylidene fluoride resin. Examples of the polyvinylidene fluoride resin include a homopolymer of vinylidene fluoride (that is, polyvinylidene fluoride); a copolymer of vinylidene fluoride and another monomer (polyvinylidene fluoride copolymer); and a mixture thereof. . Examples of monomers copolymerizable with vinylidene fluoride include, for example, tetrafluoroethylene, hexafluoropropylene, trifluoroethylene, chlorotrifluoroethylene, vinyl fluoride, and trichloroethylene. Can be.

質量 The mass ratio of vinylidene fluoride (VDF) units in the polyvinylidene fluoride copolymer is not particularly limited, but is preferably 50% by mass to 98% by mass.

It is known that polyvinylidene fluoride resin exhibits excellent compatibility with (meth) acrylate (particularly methacrylate) and polyvinyl alcohol. As the polyvinylidene fluoride resin, a homopolymer of vinylidene fluoride (that is, polyvinylidene fluoride) is preferable in order to ensure high compatibility with the water-insoluble copolymer VA.

(4) The polyvinylidene fluoride resin contained in the second hydrophilic material may be one type or two or more types.

重量 The weight average molecular weight (Mw) of the polyvinylidene fluoride resin is not particularly limited, but is preferably 50,000 to 5,000,000.

において In the present disclosure, the weight average molecular weight of the polyvinylidene fluoride resin is measured by gel permeation chromatography (GPC). The molecular weight was measured by GPC using GPC-900, a GPC device manufactured by JASCO Corporation, using two columns of TSKgel @ SUPER @ AWM-H manufactured by Tosoh Corporation, using N, N-dimethylformamide as a solvent, and heating at a temperature of 40 ° C. The measurement is performed under the conditions of ° C and a flow rate of 10 mL / min, and the molecular weight in terms of polystyrene is determined.

In the second hydrophilic material, the content of the polyvinylidene fluoride resin is preferably 40% by mass to 95% by mass based on the total amount of the water-insoluble copolymer VA and the polyvinylidene fluoride resin. When the content of the polyvinylidene fluoride-based resin is 40% by mass or more, the second hydrophilic material is easily made porous when the second hydrophilic material is arranged in the pores of the porous substrate. From this viewpoint, the content of the polyvinylidene fluoride resin based on the total amount of the water-insoluble copolymer VA and the polyvinylidene fluoride resin is more preferably 45% by mass or more, and more preferably 50% by mass or more. Is more preferable, and more preferably 55% by mass or more.
On the other hand, from the viewpoint of improving the hydrophilicity of the second hydrophilic material, the content of the polyvinylidene fluoride resin is 95% by mass or less based on the total amount of the water-insoluble copolymer VA and the polyvinylidene fluoride resin. Is preferably 85% by mass or less, and more preferably 75% by mass or less.

(4) The hydrophilic material may contain other resins other than the water-insoluble copolymer VA and the polyvinylidene fluoride resin, a surfactant, a wetting agent, a defoaming agent, a pH adjuster, a coloring agent, and the like. Examples of other resins include polyamides, polyimides, fluorine-based rubber, celluloses, polyvinyl butyral, polyvinyl pyrrolidone, and polyether.

[Hydrophilic coating layer]
The hydrophilic composite membrane of the present disclosure may be configured to further include at least one of the following first hydrophilic coating layer and second hydrophilic coating layer on one or both surfaces of the porous substrate.

First hydrophilic coating layer: a hydrophilic coating layer containing a water-insoluble copolymer having a vinyl alcohol unit and an acrylic monomer unit.
Second hydrophilic coating layer: a hydrophilic coating layer containing a water-insoluble copolymer having a vinyl alcohol unit and an acrylic monomer unit and a polyvinylidene fluoride resin in a state of being compatible with each other.

において In the present disclosure, the first hydrophilic coating layer does not include the second hydrophilic coating layer.

When the hydrophilic composite film of the present disclosure has a first hydrophilic coating layer, the first hydrophilic coating layer is preferably the outermost layer of the hydrophilic composite film on one or both surfaces of the porous substrate. .
When the hydrophilic composite film of the present disclosure has a second hydrophilic coating layer, the second hydrophilic coating layer is preferably the outermost layer of the hydrophilic composite film on one or both surfaces of the porous substrate. .

The hydrophilic composite membrane of the present disclosure has excellent wettability of an aqueous medium by providing at least one of a first hydrophilic coating layer and a second hydrophilic coating layer on one or both surfaces of a porous substrate, Superior in water permeability.

The first hydrophilic coating layer and the second hydrophilic coating layer exhibit hydrophilicity by containing the water-insoluble copolymer VA which is hydrophilic. Since the water-insoluble copolymer VA is water-insoluble, it does not easily elute from the first hydrophilic coating layer and the second hydrophilic coating layer into the aqueous medium.

The second hydrophilic coating layer contains the water-insoluble copolymer VA and the polyvinylidene fluoride-based resin in a compatible state, so that the second hydrophilic coating layer has high uniformity and hydrophilicity throughout the second hydrophilic coating layer. Is shown.

The second hydrophilic coating layer contains the water-insoluble copolymer VA and the polyvinylidene fluoride resin in a compatible state, so that the water-insoluble copolymer VA as the hydrophilic component Hardly detached from the hydrophilic coating layer.

The second hydrophilic coating layer is excellent in heat resistance, solvent insolubility, chemical resistance and mechanical strength by containing a polyvinylidene fluoride resin. Therefore, the hydrophilic composite membrane of the present disclosure having the second hydrophilic coating layer on the porous substrate has excellent heat resistance, solvent insolubility, chemical resistance, and mechanical strength.

In the present disclosure, the state in which a plurality of types of resins contained in the hydrophilic coating layer are compatible with each other, when the hydrophilic coating layer is observed at a resolution of 0.2 nm and a magnification of 30,000 times using a transmission electron microscope, It means a state in which discontinuity of the resin phase is not recognized.

Hereinafter, items common to the first hydrophilic coating layer and the second hydrophilic coating layer will be collectively described as hydrophilic coating layers.

において In the hydrophilic composite membrane of the present disclosure, the hydrophilic coating layer is preferably a porous layer from the viewpoint of better water permeability. Here, the porous layer means a layer having a large number of micropores inside, these micropores being connected, and allowing gas or liquid to pass from one side to the other side. .

厚 The thickness of the hydrophilic coating layer is not particularly limited, but is preferably 0.1 μm to 10 μm on one side.

Mass of the hydrophilic coating layer per unit area, but are not particularly limited, one-sided ^{^{0.1g / m 2 ~ 10g / m}} 2 is preferred.

When the hydrophilic coating layer is a porous layer, the porosity of the hydrophilic coating layer is not particularly limited, but is preferably 30% or more from the viewpoint of water permeability, and 80% from the viewpoint of mechanical strength. The following is preferred.

場合 When the hydrophilic coating layer is a porous layer, the average pore size of the hydrophilic coating layer is not particularly limited, but is preferably from 10 nm to 800 nm. The average pore size of the hydrophilic coating layer is a value determined by a measuring method of ASTM E1294-89 using a palm porometer.

The specific form and preferred form of the water-insoluble copolymer VA contained in the hydrophilic coating layer are the same as those described for the above-mentioned hydrophilic material.
The specific form and preferred form of the polyvinylidene fluoride resin contained in the second hydrophilic coating layer are the same as those described for the second hydrophilic material.
The specific form and preferred form of the combination and mixing ratio of the water-insoluble copolymer VA and the polyvinylidene fluoride resin contained in the second hydrophilic coating layer are the forms described for the second hydrophilic material described above. Is the same as

The hydrophilic coating layer may contain other resins other than the water-insoluble copolymer VA and the polyvinylidene fluoride-based resin, a filler, a surfactant, a wetting agent, a defoaming agent, a pH adjuster, a coloring agent, and the like. . Examples of other resins include polyamides, polyimides, fluorine-based rubber, celluloses, polyvinyl butyral, polyvinyl pyrrolidone, and polyether. Examples of the filler include inorganic fillers such as metal hydroxides, metal oxides, carbonates, sulfates, and clay minerals; and organic fillers such as particles composed of a crosslinked polymer and particles composed of a heat-resistant polymer.

表面 The surface of the hydrophilic coating layer may be subjected to various surface treatments. Examples of the surface treatment include corona treatment, plasma treatment, flame treatment, and ultraviolet irradiation treatment.

<First embodiment: Method for producing hydrophilic composite membrane>
The method for producing the hydrophilic composite membrane of the present disclosure is not particularly limited. As a general manufacturing method, there is a manufacturing method in which a hydrophilic material is arranged in pores of a porous substrate by a wet coating method or a dry coating method. In the present disclosure, the wet coating method is a method of solidifying a coating layer in a coagulation liquid, and the dry coating method is a method of drying and solidifying a coating layer. Hereinafter, an embodiment of the wet coating method will be described using a hydrophilic composite film including a second hydrophilic material and a second hydrophilic coating layer as an example.

In the wet coating method, a coating solution containing a water-insoluble copolymer VA and a polyvinylidene fluoride resin is applied onto a porous substrate, and the coating layer is immersed in a coagulation solution to solidify the coating layer. This is a method of lifting, washing and drying.

塗 The coating liquid for forming the coating layer is prepared by dissolving the water-insoluble copolymer VA and the polyvinylidene fluoride resin in a solvent. If necessary, other components other than the water-insoluble copolymer VA and the polyvinylidene fluoride resin are dissolved or dispersed in the coating liquid.

溶媒 The solvent used for preparing the coating liquid preferably contains a solvent that dissolves the water-insoluble copolymer VA and the polyvinylidene fluoride resin (hereinafter, also referred to as a “good solvent”). Examples of good solvents include polar amide solvents such as N-methylpyrrolidone, dimethylacetamide, dimethylformamide, and dimethylformamide.

溶媒 The solvent used for preparing the coating liquid preferably contains a poor solvent for the resin component from the viewpoint of making the hydrophilic material or the hydrophilic coating layer porous. Therefore, the solvent used for preparing the coating liquid is preferably a mixed solvent of a good solvent and a poor solvent for the resin component. It is preferable that the poor solvent is mixed with the good solvent in such an amount that a viscosity suitable for coating can be secured. Examples of the poor solvent include water, methanol, ethanol, propyl alcohol, butyl alcohol, butanediol, ethylene glycol, propylene glycol, and tripropylene glycol.

The solvent used for preparing the coating liquid is a mixed solvent of a good solvent and a poor solvent of the resin component from the viewpoint of making the hydrophilic material or the hydrophilic coating layer porous, and contains the good solvent in an amount of 60% by mass or more. And a mixed solvent containing 40% by mass or less of a poor solvent. Furthermore, it is preferable to adjust the mixing ratio between the good solvent and the poor solvent from the viewpoint of making it easier to penetrate the coating liquid into the pores of the porous substrate. A surfactant may be added to the coating liquid. The addition of the surfactant lowers the surface tension of the coating liquid and makes it easier for the coating liquid to penetrate into the pores of the porous substrate.

The resin concentration of the coating solution is preferably from 1% by mass to 15% by mass, more preferably from 2% by mass to 13% by mass, and more preferably from 3% by mass to 10% from the viewpoint of making the hydrophilic material or the hydrophilic coating layer porous. % Is more preferred.

The coating liquid is preferably a one-phase liquid in which the water-insoluble copolymer VA and the polyvinylidene fluoride resin are compatible. A coating layer is formed using a one-phase coating liquid, and by solidifying the coating layer, a hydrophilic material in which the water-insoluble copolymer VA and the polyvinylidene fluoride-based resin are compatible with each other; A hydrophilic coating layer is formed.

手段 Examples of means for applying the coating liquid to the porous substrate include a Meyer bar, a die coater, a reverse roll coater, a roll coater, and a gravure coater. In order to impregnate the coating liquid into the pores of the porous substrate, for example, increase the coating amount of the coating liquid, increase the contact pressure of the above-described coating means on the porous substrate, and the like. May be performed. The coating of the coating liquid into the pores of the porous substrate may be performed by immersing the porous substrate in the coating liquid.

固 The solidification of the coating layer is performed by immersing the porous substrate on which the coating layer has been formed in a coagulation liquid to solidify the resin component in the coating layer. Thereby, a composite film composed of the porous substrate, the hydrophilic material, and the hydrophilic coating layer is obtained.

Examples of the coagulation liquid include water; a mixture of water and a good solvent and a poor solvent used in the preparation of the coating liquid. It is preferable from the viewpoint of production that the mixing ratio of the good solvent and the poor solvent is adjusted to the mixing ratio of the mixed solvent used for preparing the coating liquid. The content of water in the coagulation liquid is preferably from 40% by mass to 90% by mass from the viewpoint of making the hydrophilic material or the hydrophilic coating layer porous. The temperature of the coagulation liquid is not particularly limited, but is preferably from 20 ° C to 50 ° C.

後 After solidifying the coating layer in the coagulation liquid, pull up the composite film from the coagulation liquid and wash with water. The coagulation liquid is removed from the composite membrane by washing with water. Furthermore, water is removed from the composite membrane by drying. Washing is performed, for example, by transporting the composite membrane in a water bath. Drying is performed, for example, by transporting the composite film in a high-temperature environment, blowing air on the composite film, and bringing the composite film into contact with a heat roll. The drying temperature is preferably from 40 to 120 ° C, more preferably from 55 to 105 ° C.

(4) The hydrophilic composite film provided with the first hydrophilic material and the first hydrophilic coating layer can be manufactured by using a coating liquid containing no polyvinylidene fluoride-based resin in the above-mentioned wet coating method.

A hydrophilic composite film having no hydrophilic coating layer on a porous substrate can be prepared by reducing the coating amount of the coating liquid on the porous substrate, or after coating the porous substrate. It can be manufactured by removing the coating liquid adhering to the surface.

親水 The hydrophilic composite membrane of the present disclosure can also be manufactured by a dry coating method. The dry coating method is a method in which a coating liquid is applied to a porous base material, and the coating layer is dried to evaporate and remove the solvent, thereby solidifying the coating layer. However, the dry coating method is more preferable than the wet coating method since the coated layer after drying tends to be denser than the wet coating method, so that a good porous structure can be obtained.

<Second embodiment: hydrophilic porous membrane>
The hydrophilic porous membrane of the present disclosure contains a polyvinylidene fluoride resin and a water-insoluble copolymer having a vinyl alcohol unit and an acrylic monomer unit (water-insoluble copolymer VA) in a compatible state. Is a hydrophilic porous membrane.

In the present disclosure, a state in which a plurality of types of resins contained in a porous film are compatible with each other means that when the porous film is observed with a transmission electron microscope at a resolution of 0.2 nm and a magnification of 30000 times, the resin phase is incompatible. It means the state where continuation is not recognized.

The water-insoluble copolymer VA exhibits hydrophilicity due to the hydroxyl group of the vinyl alcohol unit. The hydrophilic porous membrane of the present disclosure exhibits hydrophilicity by including a water-insoluble copolymer VA that is hydrophilic. Since the hydrophilic porous membrane of the present disclosure contains the polyvinylidene fluoride resin and the water-insoluble copolymer VA in a compatible state, the hydrophilic porous membrane exhibits high uniformity and hydrophilicity throughout.

Since the hydrophilic porous membrane of the present disclosure contains the polyvinylidene fluoride resin and the water-insoluble copolymer VA in a compatible state, desorption of the water-insoluble copolymer VA as a hydrophilic component is prevented. Less likely to occur. Moreover, in the hydrophilic porous membrane of the present disclosure, the hydrophilic component is less likely to elute into the aqueous medium because the water-insoluble copolymer VA is insoluble in water.

は In the hydrophilic porous membrane of the present disclosure, the contact angle of water measured on one or both sides under the following measurement conditions is preferably 60 degrees or less, and the smaller the contact angle of water, the more preferable. The hydrophilic porous membrane of the present disclosure, on one or both sides, when measuring the contact angle of water under the following measurement conditions, is so hydrophilic that water droplets penetrate into the inside of the porous membrane and cannot be measured. Is more preferred. The method for measuring the contact angle of water is as described above in the first embodiment.

The hydrophilic porous membrane of the present disclosure has pores or voids inside.
One embodiment of the hydrophilic porous membrane of the present disclosure is a microporous membrane containing a polyvinylidene fluoride-based resin and a water-insoluble copolymer VA in a compatible state. A microporous membrane is a membrane that has a large number of micropores inside and has a structure in which these micropores are connected, so that gas or liquid can pass from one surface to the other. I do.
Another embodiment of the hydrophilic porous membrane of the present disclosure includes a woven or nonwoven fabric made of a fibrous material containing a polyvinylidene fluoride resin and a water-insoluble copolymer VA in a compatible state.

The hydrophilic porous membrane of the present disclosure is used, for example, for the purpose of separation, purification, concentration, fractionation, and the like of a substance dispersed or dissolved in an aqueous medium.
Examples of the structure of the hydrophilic porous membrane of the present disclosure include hollow fiber membranes (hollow fiber type, immersion type, cartridge type), tubular membranes (tubular type, monolith type, immersion type), flat membranes (flat membrane cell, spiral type, Pleat type, plate type) and the like.
Examples of the type of the hydrophilic porous membrane according to the present disclosure according to the pore size include a microfiltration membrane, an ultrafiltration membrane, a nanofiltration membrane, and a reverse osmosis membrane.
Applications of the hydrophilic porous membrane of the present disclosure include, for example, water purification, sanitization, desalination of seawater, artificial dialysis, pharmaceutical production, food production, protein separation, and the like.

膜厚 The thickness, pore size, and porosity of the hydrophilic porous membrane of the present disclosure are not particularly limited, and may be selected according to the application, structure, or type.

一つ One embodiment of the hydrophilic porous membrane of the present disclosure includes a hydrophilic porous membrane having a thickness of 5 μm to 300 μm.

一つ One embodiment of the hydrophilic porous membrane of the present disclosure includes a hydrophilic porous membrane having an average pore diameter of 1 nm to 900 nm.

一つ One embodiment of the hydrophilic porous membrane of the present disclosure includes a hydrophilic porous membrane having a porosity of 4% to 70%.

表面 Various surface treatments may be applied to the surface of the hydrophilic porous membrane of the present disclosure. Examples of the surface treatment include corona treatment, plasma treatment, flame treatment, and ultraviolet irradiation treatment.

成分 Hereinafter, components contained in the hydrophilic porous membrane of the present disclosure will be described.

[Polyvinylidene fluoride resin]
The hydrophilic porous membrane of the present disclosure contains a polyvinylidene fluoride resin. The hydrophilic porous membrane of the present disclosure is excellent in heat resistance, solvent insolubility, chemical resistance, and mechanical strength by containing a polyvinylidene fluoride resin.

モノマー The monomer units, composition, specific examples and preferred embodiments of the polyvinylidene fluoride resin are as described above in the first embodiment.

は The polyvinylidene fluoride-based resin contained in the hydrophilic porous membrane of the present disclosure may be one type or two or more types.

重量 The weight average molecular weight (Mw) of the polyvinylidene fluoride resin is not particularly limited, but is preferably 50,000 to 5,000,000, and more preferably 500,000 to 3,000,000 from the viewpoint of film forming properties. The method for measuring the weight average molecular weight of the polyvinylidene fluoride resin is as described above in the first embodiment.

In the hydrophilic porous membrane of the present disclosure, the content of the polyvinylidene fluoride resin is preferably 40% by mass to 95% by mass based on the total amount of the polyvinylidene fluoride resin and the water-insoluble copolymer VA. When the content of the polyvinylidene fluoride resin is 40% by mass or more, the film is easily made porous when forming the film. From this viewpoint, the content of the polyvinylidene fluoride resin based on the total amount of the polyvinylidene fluoride resin and the water-insoluble copolymer VA is more preferably 45% by mass or more, and more preferably 50% by mass or more. Is more preferable, and more preferably 55% by mass or more.
On the other hand, from the viewpoint of improving the hydrophilicity of the hydrophilic porous membrane of the present disclosure, the content of the polyvinylidene fluoride resin is not more than 95% by mass with respect to the total amount of the polyvinylidene fluoride resin and the water-insoluble copolymer VA. It is preferably at most 85% by mass, more preferably at most 75% by mass.

[Water-insoluble copolymer VA]
The water-insoluble copolymer VA has at least a vinyl alcohol unit and an acrylic monomer unit, and is water-insoluble.

モノマー The monomer units, composition, specific examples and preferred embodiments of the water-insoluble copolymer VA are as described above in the first embodiment.

は The water-insoluble copolymer VA contained in the hydrophilic porous membrane of the present disclosure may be one type or two or more types.

In the hydrophilic porous membrane of the present disclosure, the content of the water-insoluble copolymer VA is preferably 5% by mass to 60% by mass with respect to the total amount of the polyvinylidene fluoride resin and the water-insoluble copolymer VA. When the content of the water-insoluble copolymer VA is 60% by mass or less, the film is easily made porous when the film is formed. From this viewpoint, the content of the water-insoluble copolymer VA based on the total amount of the polyvinylidene fluoride resin and the water-insoluble copolymer VA is more preferably 55% by mass or less, and is 50% by mass or less. Is more preferably 45% by mass or less.
On the other hand, from the viewpoint of improving the hydrophilicity of the hydrophilic porous membrane of the present disclosure, the content of the water-insoluble copolymer VA with respect to the total amount of the polyvinylidene fluoride resin and the water-insoluble copolymer VA is 5% by mass or more. Is preferably 15% by mass or more, more preferably 25% by mass or more.

[Other ingredients]
The hydrophilic porous membrane of the present disclosure may contain other components as long as the compatibility between the polyvinylidene fluoride resin and the water-insoluble copolymer VA is not impaired. Other components include other resins and fillers other than the polyvinylidene fluoride resin and the water-insoluble copolymer VA.

Other resins include polyamides, polyimides, fluororubbers, celluloses, polyvinyl butyral, polyvinyl pyrrolidone, polyether and the like.

Examples of the filler include inorganic fillers such as metal hydroxides, metal oxides, carbonates, sulfates, and clay minerals; and organic fillers such as particles made of a crosslinked polymer and particles made of a heat-resistant polymer.

親水 The hydrophilic porous membrane of the present disclosure may contain additives such as a surfactant, a wetting agent, an antifoaming agent, a pH adjuster, and a coloring agent.

として As an example of a composite including the hydrophilic porous membrane of the present disclosure, a composite membrane including a base material and the hydrophilic porous membrane of the present disclosure disposed on the base material is exemplified.

Examples of the substrate include a porous substrate and a release sheet.
The porous substrate is laminated with the hydrophilic porous membrane, for example, for the purpose of reinforcing the strength of the hydrophilic porous membrane. Examples of the porous substrate include a microporous film made of a resin; a porous sheet such as a nonwoven fabric and paper;
The release sheet is, for example, a sheet used as a base material for producing a hydrophilic porous membrane and separated from the hydrophilic porous membrane when the hydrophilic porous membrane is used.

<Second embodiment: Method for producing hydrophilic porous membrane>
The method for producing the hydrophilic porous membrane of the present disclosure is not particularly limited. When the hydrophilic porous membrane of the present disclosure is a microporous membrane and a flat membrane, a general production method includes a production method in which a hydrophilic porous membrane is formed on a substrate by a wet coating method or a dry coating method. . In the present disclosure, the wet coating method is a method of solidifying a coating layer in a coagulation liquid, and the dry coating method is a method of drying and solidifying a coating layer. Hereinafter, embodiments of the wet coating method when the hydrophilic porous membrane of the present disclosure is a microporous membrane and a flat membrane will be described.

In the wet coating method, a coating liquid containing a polyvinylidene fluoride resin and a water-insoluble copolymer VA is coated on a base material, immersed in a coagulation liquid to solidify the coating layer, and then withdrawn from the coagulation liquid and washed with water. And drying.

塗 The coating liquid for forming the coating layer is prepared by dissolving a polyvinylidene fluoride resin and a water-insoluble copolymer VA in a solvent. In the coating liquid, other components other than the polyvinylidene fluoride resin and the water-insoluble copolymer VA are dissolved or dispersed as necessary. The type of solvent, the composition of the solvent, the resin concentration, and the means for applying the coating liquid according to the coating liquid are as described above in the first embodiment.

固 The solidification of the coating layer is performed by immersing the base material on which the coating layer has been formed in a coagulating liquid to solidify the resin component in the coating layer. Thereby, a composite film composed of the base material and the porous film is obtained. The type of the solvent, the composition of the solvent, and the temperature of the solvent relating to the coagulation liquid are as described above in the first embodiment.

後 After solidifying the coating layer in the coagulation liquid, pull up the composite film from the coagulation liquid and wash with water. The coagulation liquid is removed from the composite membrane by washing with water. Furthermore, water is removed from the composite membrane by drying. The washing method, the drying method, and the drying conditions are as described above in the first embodiment.

複合 Through the above steps, a composite membrane including the substrate and the hydrophilic porous membrane of the present disclosure is obtained. Further, by peeling the porous membrane from the substrate, the hydrophilic porous membrane of the present disclosure is obtained.

親水 The hydrophilic porous membrane of the present disclosure can also be manufactured by a dry coating method. The dry coating method is a method in which a coating liquid is applied to a substrate, and a coating layer is dried to remove a solvent by volatilization, thereby forming a porous film on the substrate. However, the dry coating method is more preferable than the wet coating method since the coated layer after drying tends to be denser than the wet coating method, so that a good porous structure can be obtained.

<Second embodiment: hydrophilic resin composition>
The hydrophilic resin composition of the present disclosure contains a polyvinylidene fluoride resin and a water-insoluble copolymer having a vinyl alcohol unit and an acrylic monomer unit (water-insoluble copolymer VA) in a state of being compatible with each other. Hydrophilic resin composition. The hydrophilic resin composition of the present disclosure is a solid resin composition.

Examples of the form of the hydrophilic resin composition of the present disclosure include a hydrophilic porous membrane of the present disclosure.
Another embodiment of the hydrophilic resin composition of the present disclosure includes fibers, particles, non-porous films, and the like.

親水 The hydrophilic resin composition of the present disclosure exhibits hydrophilicity by containing the water-insoluble copolymer VA which is hydrophilic. The hydrophilic resin composition of the present disclosure includes the polyvinylidene fluoride resin and the water-insoluble copolymer VA in a state of being compatible with each other, so that the hydrophilic resin composition has high uniformity and hydrophilicity throughout. Show.

The hydrophilic resin composition of the present disclosure includes the polyvinylidene fluoride resin and the water-insoluble copolymer VA in a state of being compatible with each other, thereby desorbing the water-insoluble copolymer VA as a hydrophilic component. Is less likely to occur. Further, in the hydrophilic resin composition of the present disclosure, since the water-insoluble copolymer VA is water-insoluble, the hydrophilic component hardly elutes in the aqueous medium.

Specific and preferred embodiments of the polyvinylidene fluoride-based resin contained in the hydrophilic resin composition of the present disclosure are the same as those described above for the hydrophilic porous membrane of the present disclosure.
Specific and preferred embodiments of the water-insoluble copolymer VA contained in the hydrophilic resin composition of the present disclosure are the same as those described above for the hydrophilic porous membrane of the present disclosure.
Specific and preferred embodiments of the combination and mixing ratio of the polyvinylidene fluoride resin and the water-insoluble copolymer VA in the hydrophilic resin composition of the present disclosure are the same as those described above for the hydrophilic porous membrane of the present disclosure. It is.

The hydrophilic resin composition of the present disclosure includes a resin other than the polyvinylidene fluoride resin and the water-insoluble copolymer VA, a filler, a surfactant, a wetting agent, a defoaming agent, a pH adjuster, a coloring agent, and the like. You may go out. Specific examples of these other components are the same as the specific examples described above for the hydrophilic porous membrane of the present disclosure.

製造 The method for producing the hydrophilic resin composition of the present disclosure is not particularly limited. As a general production method, there is a production method in which a polyvinylidene fluoride resin and a water-insoluble copolymer VA are dissolved in an organic solvent to prepare a resin solution, and then the organic solvent is removed from the resin solution. As the organic solvent, an organic solvent containing at least the above-mentioned good solvent is preferable.

親水 The hydrophilic composite membrane of the present disclosure will be more specifically described below with reference to examples. Materials, usage amounts, ratios, processing procedures, and the like shown in the following examples can be appropriately changed without departing from the spirit of the present disclosure. Therefore, the scope of the hydrophilic composite membrane of the present disclosure should not be construed as being limited by the specific examples described below.

<First embodiment: Preparation of hydrophilic composite membrane>
(1) Composite membrane having first hydrophilic material in pores of porous substrate [Example 1]
The following water-insoluble copolymer VA was mixed with a mixed solvent of dimethylacetamide (DMAc) and tripropylene glycol (TPG) (DMAc: TPG = 80: 20 [mass ratio]) so that the resin concentration became 5.0% by mass. ) To obtain a coating solution.

・ Water-insoluble copolymer VA
Polymer obtained by polymerizing methyl methacrylate on partially saponified polyvinyl alcohol (degree of polymerization: 500, degree of saponification: 74 mol%), polymerization ratio (mass basis) = 63:37. Solubility: 1.8 g / 100 g water.

(4) A microporous polyethylene film (9.0 μm thick, Gurley value 170 sec / 100 mL, porosity 43%, average pore diameter 45 nm, water contact angle 103 °) was prepared as a porous substrate.

(4) The porous substrate was immersed in the coating solution to impregnate the pores of the porous substrate with the coating solution and then pulled up to remove the coating solution adhering to the surface of the porous substrate. Next, the porous substrate containing the coating liquid in the pores is dipped in a coagulating liquid (water: DMAc: TPG = 62.5: 30: 7.5 [mass ratio], liquid temperature 35 ° C.) to perform coating. The liquid solidified. Next, this was washed with water and dried to obtain a composite film. This composite membrane had the first hydrophilic material in the pores of the microporous polyethylene membrane.

[Example 2]
A composite membrane was obtained in the same manner as in Example 1, except that the water-insoluble copolymer VA was changed as follows.

・ Water-insoluble copolymer VA
Polymer obtained by polymerizing methyl methacrylate on partially saponified polyvinyl alcohol (degree of polymerization: 500, degree of saponification: 75 mol%), polymerization ratio (mass basis) = 40:60. Solubility: 1.2 g / 100 g water.

[Example 3]
A composite membrane was obtained in the same manner as in Example 1, except that the water-insoluble copolymer VA was changed as follows.

・ Water-insoluble copolymer VA
Polymer obtained by polymerizing methyl methacrylate on partially saponified polyvinyl alcohol (degree of polymerization: 500, degree of saponification: 75 mol%), polymerization ratio (mass basis) = 85:15. Solubility: 2.0 g / 100 g water.

[Example 4]
A composite membrane was obtained in the same manner as in Example 1, except that the water-insoluble copolymer VA was changed as follows.

・ Water-insoluble copolymer VA
Polymer obtained by polymerizing methyl methacrylate and acrylic acid on partially saponified polyvinyl alcohol (degree of polymerization: 500, degree of saponification: 72 mol%), polymerization ratio (mass basis) = 63: 30: 7. Solubility: 1.6 g / 100 g water.

[Example 5]
A composite membrane was obtained in the same manner as in Example 1, except that the water-insoluble copolymer VA was changed as follows.

・ Water-insoluble copolymer VA
Polymer obtained by polymerizing methyl methacrylate and styrene on partially saponified polyvinyl alcohol (degree of polymerization: 500, degree of saponification: 74 mol%), polymerization ratio (mass basis) = 63: 30: 7. Solubility: 1.3 g / 100 g water.

[Example 6]
A composite membrane was obtained in the same manner as in Example 1, except that the water-insoluble copolymer VA was changed as follows.

・ Water-insoluble copolymer VA
Polymer obtained by polymerizing methyl methacrylate and methyl acrylate on partially saponified polyvinyl alcohol (polymerization degree: 500, saponification degree: 74 mol%), polymerization ratio (mass basis) = 63: 30: 7. Solubility: 1.4 g / 100 g water.

[Example 7]
A composite membrane was obtained in the same manner as in Example 1, except that the water-insoluble copolymer VA was changed as follows.

・ Water-insoluble copolymer VA
Polymer obtained by polymerizing methyl methacrylate and methacrylic acid on partially saponified polyvinyl alcohol (degree of polymerization: 500, degree of saponification: 74 mol%), polymerization ratio (mass basis) = 63: 30: 7. Solubility: 1.4 g / 100 g water.

[Example 8-1]
The following water-insoluble copolymer VA is dissolved in a mixed solvent of water and ethanol (water: ethanol = 50: 50 [volume ratio]) so that the resin concentration becomes 0.2% by mass, and the coating liquid is prepared. Obtained.

・ Water-insoluble copolymer VA
Polymer obtained by polymerizing methyl methacrylate and acrylic acid on partially saponified polyvinyl alcohol (polymerization degree: 500, saponification degree: 55 mol%), polymerization ratio (mass basis) = 63: 30: 7. Solubility: 1.3 g / 100 g water.

ポリエチレン The polyethylene microporous membrane used in Example 1 was prepared as a porous substrate.

(4) The porous substrate was immersed in the coating solution to impregnate the pores of the porous substrate with the coating solution and then pulled up to remove the coating solution adhering to the surface of the porous substrate. Next, this was dried to obtain a composite membrane. This composite membrane had the first hydrophilic material in the pores of the microporous polyethylene membrane.

[Example 8-2]
A composite film was obtained in the same manner as in Example 8-1, except that the water-insoluble copolymer VA was changed as follows.

・ Water-insoluble copolymer VA
Polymer obtained by polymerizing methyl methacrylate and acrylic acid on partially saponified polyvinyl alcohol (degree of polymerization: 500, degree of saponification: 60 mol%), polymerization ratio (mass basis) = 63: 30: 7. Solubility: 1.4 g / 100 g water.

[Example 8-3]
A composite film was obtained in the same manner as in Example 8-1, except that the water-insoluble copolymer VA was changed as follows.

・ Water-insoluble copolymer VA
Polymer obtained by polymerizing methyl methacrylate and acrylic acid on partially saponified polyvinyl alcohol (degree of polymerization: 500, degree of saponification: 65 mol%), polymerization ratio (mass basis) = 63: 30: 7. Solubility: 1.5 g / 100 g water.

[Example 9]
A composite film was obtained in the same manner as in Example 8-1, except that the water-insoluble copolymer VA was changed as follows.

・ Water-insoluble copolymer VA
Polymer obtained by polymerizing methyl methacrylate and acrylic acid on partially saponified polyvinyl alcohol (degree of polymerization: 500, degree of saponification: 60 mol%), polymerization ratio (by mass) = 63: 15: 22. Solubility: 1.6 g / 100 g water.

[Comparative Example 1]
The polyethylene microporous membrane used in Example 1 was used as the membrane of Comparative Example 1.

[Comparative Example 2]
The following water-soluble polymer was dissolved in a mixed solvent of DMAc and TPG (DMAc: TPG = 80: 20 [mass ratio]) so that the resin concentration was 2.0% by mass, to obtain a coating liquid. .

-Water-soluble polymer Partially saponified polyvinyl alcohol (polymerization degree: 500, saponification degree: 74 mol%). Solubility: 96 g / 100 g water.

The porous substrate was immersed in the coating solution to impregnate the pores of the porous substrate with the coating solution, and then lifted up to remove the coating solution adhering to the surface of the porous substrate. Next, the porous substrate containing the coating liquid in the pores is dipped in a coagulation liquid (water: DMAc: TPG = 62.5: 30: 7.5 [mass ratio], liquid temperature 35 ° C.) to perform coating. The liquid solidified. Next, this was washed with water and dried to obtain a composite film. This composite membrane had the water-soluble polymer in pores of the microporous polyethylene membrane.

(2) Composite membrane having first hydrophilic material in pores of porous substrate and having first hydrophilic coating layers on both surfaces of porous substrate [Example 11]
The coating liquid and the porous substrate used in Example 1 were used. The coating liquid was applied to both sides of the porous substrate (at this time, coating was performed so that the coating amounts on the front and back sides were equal), and the coagulating liquid (water: DMAc: TPG = 62.5: 30) : 7.5 [mass ratio], liquid temperature 35 ° C) to be solidified. Next, this was washed with water and dried to obtain a composite film. This composite membrane had the first hydrophilic material in the pores of the microporous polyethylene membrane, and had the first hydrophilic coating layers on both sides of the microporous polyethylene membrane.

[Example 12]
A composite membrane was obtained in the same manner as in Example 11, except that the water-insoluble copolymer VA was changed to the water-insoluble copolymer VA used in Example 2.

Example 13
A composite membrane was obtained in the same manner as in Example 11, except that the water-insoluble copolymer VA was changed to the water-insoluble copolymer VA used in Example 3.

[Example 14]
A composite membrane was obtained in the same manner as in Example 11, except that the water-insoluble copolymer VA was changed to the water-insoluble copolymer VA used in Example 4.

[Example 15]
A composite membrane was obtained in the same manner as in Example 11, except that the water-insoluble copolymer VA was changed to the water-insoluble copolymer VA used in Example 5.

[Example 16]
A composite membrane was obtained in the same manner as in Example 11, except that the water-insoluble copolymer VA was changed to the water-insoluble copolymer VA used in Example 6.

[Example 17]
A composite membrane was obtained in the same manner as in Example 11, except that the water-insoluble copolymer VA was changed to the water-insoluble copolymer VA used in Example 7.

(3) Composite membrane having second hydrophilic material in pores of porous substrate [Example 21]
The water-insoluble copolymer VA used in Example 1 was mixed with the following polyvinylidene fluoride-based resin in dimethylacetamide (DMAc) at a mass ratio shown in Table 4 so that the resin concentration was 5.0 mass%. And tripropylene glycol (TPG) were dissolved in a mixed solvent (DMAc: TPG = 80: 20 [mass ratio]) to obtain a coating liquid.

・ Polyvinylidene fluoride resin (PVDF resin)
Vinylidene fluoride-hexafluoropropylene copolymer, hexafluoropropylene (HFP) unit: 12.4% by mass, weight average molecular weight (Mw): 860,000.

(4) The porous substrate was immersed in the coating solution to impregnate the pores of the porous substrate with the coating solution and then pulled up to remove the coating solution adhering to the surface of the porous substrate. Next, the porous substrate containing the coating liquid in the pores is dipped in a coagulating liquid (water: DMAc: TPG = 62.5: 30: 7.5 [mass ratio], liquid temperature 35 ° C.) to perform coating. The liquid solidified. Next, this was washed with water and dried to obtain a composite film. This composite membrane had the second hydrophilic material in the pores of the polyethylene microporous membrane.

[Example 22]
A composite film was obtained in the same manner as in Example 21, except that the mixing ratio of the water-insoluble copolymer VA and the polyvinylidene fluoride resin was changed as shown in Table 4.

[Example 23]
A composite film was obtained in the same manner as in Example 21, except that the mixing ratio of the water-insoluble copolymer VA and the polyvinylidene fluoride resin was changed as shown in Table 4.

[Example 24]
A composite membrane was obtained in the same manner as in Example 21, except that the water-insoluble copolymer VA was changed to the water-insoluble copolymer VA used in Example 2.

[Example 25]
A composite membrane was obtained in the same manner as in Example 21, except that the water-insoluble copolymer VA was changed to the water-insoluble copolymer VA used in Example 3.

[Example 26]
A composite membrane was obtained in the same manner as in Example 21, except that the water-insoluble copolymer VA was changed to the water-insoluble copolymer VA used in Example 4.

[Example 27]
A composite membrane was obtained in the same manner as in Example 21, except that the water-insoluble copolymer VA was changed to the water-insoluble copolymer VA used in Example 5.

[Example 28]
A composite membrane was obtained in the same manner as in Example 21, except that the water-insoluble copolymer VA was changed to the water-insoluble copolymer VA used in Example 6.

[Example 29]
A composite membrane was obtained in the same manner as in Example 21 except that the water-insoluble copolymer VA was changed to the water-insoluble copolymer VA used in Example 7.

[Example 30]
A composite film was obtained in the same manner as in Example 21 except that the polyvinylidene fluoride resin was changed as follows.

・ Polyvinylidene fluoride resin (PVDF resin)
Vinylidene fluoride homopolymer, weight average molecular weight (Mw): 580,000.

[Comparative Example 3]
A composite film was obtained in the same manner as in Example 21, except that the water-insoluble copolymer VA was changed to the water-soluble polymer used in Comparative Example 2. This composite membrane had a hydrophilic material composed of the water-soluble polymer and PVDF resin in the pores of the polyethylene microporous membrane.

(4) Composite membrane having second hydrophilic material in pores of porous substrate and second hydrophilic coating layers on both sides of porous substrate [Example 31]
The coating liquid and the porous substrate used in Example 21 were used. The coating liquid was applied to both sides of the porous substrate (at this time, coating was performed so that the coating amounts on the front and back sides were equal), and the coagulating liquid (water: DMAc: TPG = 62.5: 30) : 7.5 [mass ratio], liquid temperature 35 ° C) to be solidified. Next, this was washed with water and dried to obtain a composite film. This composite membrane had the second hydrophilic material in the pores of the microporous polyethylene membrane, and had the second hydrophilic coating layers on both sides of the microporous polyethylene membrane.

[Example 32]
A composite film was obtained in the same manner as in Example 31, except that the mixing ratio of the water-insoluble copolymer VA and the polyvinylidene fluoride resin was changed as shown in Table 5.

[Example 33]
A composite film was obtained in the same manner as in Example 31, except that the mixing ratio of the water-insoluble copolymer VA and the polyvinylidene fluoride resin was changed as shown in Table 5.

[Example 34]
A composite membrane was obtained in the same manner as in Example 31, except that the water-insoluble copolymer VA was changed to the water-insoluble copolymer VA used in Example 2.

[Example 35]
A composite membrane was obtained in the same manner as in Example 31, except that the water-insoluble copolymer VA was changed to the water-insoluble copolymer VA used in Example 3.

[Example 36]
A composite membrane was obtained in the same manner as in Example 31, except that the water-insoluble copolymer VA was changed to the water-insoluble copolymer VA used in Example 4.

[Example 37]
A composite membrane was obtained in the same manner as in Example 31, except that the water-insoluble copolymer VA was changed to the water-insoluble copolymer VA used in Example 5.

[Example 38]
A composite membrane was obtained in the same manner as in Example 31, except that the water-insoluble copolymer VA was changed to the water-insoluble copolymer VA used in Example 6.

[Example 39]
A composite membrane was obtained in the same manner as in Example 31, except that the water-insoluble copolymer VA was changed to the water-insoluble copolymer VA used in Example 7.

[Example 40]
A composite film was obtained in the same manner as in Example 31, except that the polyvinylidene fluoride resin was changed to the polyvinylidene fluoride resin used in Example 30.

<First embodiment: Performance evaluation of hydrophilic composite membrane>
Physical property measurement and performance evaluation of each composite membrane of the example and the comparative example were performed as follows. The results are shown in Tables 1 to 5.

[State of resin in composite membrane]
In Examples and Comparative Examples using a polyvinylidene fluoride resin, the composite membrane was cut in the thickness direction with an ultramicrotome device to produce a thin sample. The slice samples were stained for 24 hours by a heavy metal staining method in a desiccator at 25 ° C. The stained slice sample was observed with a transmission electron microscope (JEM-1400 Plus, manufactured by JEOL Ltd.) at a resolution of 0.2 nm and a magnification of 30,000 to confirm that the resin components were compatible.

[Thickness of composite membrane]
The thickness of the composite film was determined by measuring 20 points with a contact-type thickness gauge (LITEMATIC VL-50, Mitutoyo Corporation) and averaging the measured values. The measuring terminal used was a cylindrical terminal having a diameter of 5 mm, and was adjusted so that a load of 0.01 N was applied during the measurement.

[Gurle value]
The Gurley value (second / 100 mL) of the composite membrane was measured using a Gurley type densometer (Toyo Seiki Co., Ltd., GB-B2C) according to JIS P8117: 2009.

[Mass change]
The composite membrane was cut out into a size of 50 mm × 50 mm, which was used as a sample. The sample was immersed in 100 mL of water at a liquid temperature of 30 ° C., and stirred for 24 hours with a stirring blade. Next, the sample was taken out and vacuum-dried at a temperature of 60 ° C. The mass change of the composite membrane before and after the treatment was calculated according to the following equation.

Mass change (%) = {(mass of composite membrane before treatment) − (mass of composite membrane after treatment)} (mass of composite membrane before treatment) × 100

[Water permeability]
A 50 mm × 50 mm composite membrane was sandwiched between an upper and lower split type separator (Kiriyama Separate 55Z set: filtration surface inner diameter 38 mm), and 50 mL of distilled water was suction-filtered (vacuum degree 4 kPa). The above suction filtration was repeated 10 times, and the condition of water flow was observed.

<Second embodiment: Preparation of hydrophilic porous membrane>
[Example 101]
Dimethylacetamide (DMAc) and tripropylene glycol (TPG) were mixed with the following polyvinylidene fluoride resin and water-insoluble copolymer VA at a mass ratio shown in Table 6 so that the resin concentration became 5.0% by mass. )) (DMAc: TPG = 80: 20 [mass ratio]) to obtain a coating liquid.

The coating liquid is coated on glass using a doctor blade film applicator, and immersed in a coagulation liquid (water: DMAc: TPG = 62.5: 30: 7.5 [mass ratio], liquid temperature 35 ° C). And solidified. Next, this was washed with water, dried, and peeled off from the glass to obtain a porous film.

[Example 102]
A porous membrane was obtained in the same manner as in Example 101, except that the mixing ratio of the polyvinylidene fluoride resin and the water-insoluble copolymer VA was changed as shown in Table 6.

[Example 103]
A porous membrane was obtained in the same manner as in Example 101, except that the mixing ratio of the polyvinylidene fluoride resin and the water-insoluble copolymer VA was changed as shown in Table 6.

[Example 104]
A porous membrane was obtained in the same manner as in Example 101, except that the water-insoluble copolymer VA was changed as follows.

[Example 105]
A porous membrane was obtained in the same manner as in Example 101, except that the water-insoluble copolymer VA was changed as follows.

[Example 106]
A porous membrane was obtained in the same manner as in Example 101, except that the water-insoluble copolymer VA was changed as follows.

[Example 107]
A porous membrane was obtained in the same manner as in Example 101, except that the water-insoluble copolymer VA was changed as follows.

[Example 108]
A porous membrane was obtained in the same manner as in Example 101, except that the water-insoluble copolymer VA was changed as follows.

[Example 109]
A porous membrane was obtained in the same manner as in Example 101, except that the water-insoluble copolymer VA was changed as follows.

[Example 110]
A porous membrane was obtained in the same manner as in Example 101, except that the polyvinylidene fluoride resin was changed as follows.

[Comparative Example 101]
A porous membrane was obtained in the same manner as in Example 101, except that a coating liquid was obtained by dissolving only a polyvinylidene fluoride resin in a mixed solvent without using the water-insoluble copolymer VA.

[Comparative Example 102]
A porous membrane was obtained in the same manner as in Example 101 except that the water-insoluble copolymer VA was changed to the following water-soluble polymer.

[Comparative Example 103]
A hydrophilic layer was provided on the polyvinylidene fluoride resin porous film obtained in Comparative Example 101 by the following treatment method.

The water-insoluble copolymer VA used in Example 101 was dissolved in a mixed solvent of DMAc and TPG (DMAc: TPG = 80: 20 [mass ratio]) so that the resin concentration was 2.0% by mass. A coating liquid was obtained. This coating liquid was applied to both surfaces of the polyvinylidene fluoride resin obtained in Comparative Example 101 (so that the coating amounts on the front and back sides were equal), and the coagulating liquid was used. (Water: DMAc: TPG = 62.5: 30: 7.5 [mass ratio], liquid temperature 35 ° C.) to be solidified. Next, this was washed with water and dried to obtain a porous film in which both surfaces of a porous film of polyvinylidene fluoride resin were coated with a water-insoluble copolymer VA.

<Second embodiment: Performance evaluation of hydrophilic porous membrane>
Physical property measurement and performance evaluation of each of the porous membranes of Examples 101 to 110 and Comparative Examples 101 to 103 were performed in the same manner as the physical property measurement and performance evaluation in the first embodiment. The results are shown in Tables 6 and 7.

The disclosure of Japanese Patent Application No. 2018-128498 filed on July 5, 2018 is incorporated herein by reference in its entirety. The disclosure of Japanese Patent Application No. 2018-128499 filed on Jul. 5, 2018 is incorporated herein by reference in its entirety.

All documents, patent applications, and technical standards mentioned herein are to the same extent as if each individual document, patent application, and technical standard were specifically and individually stated to be incorporated by reference. Incorporated herein by reference.

Claims

A porous substrate,
Present in the pores of the porous substrate, at least one hydrophilic material of the following first hydrophilic material and second hydrophilic material,
A hydrophilic composite membrane comprising:
First hydrophilic material: a hydrophilic material containing a water-insoluble copolymer having a vinyl alcohol unit and an acrylic monomer unit.
Second hydrophilic material: a hydrophilic material containing a water-insoluble copolymer having a vinyl alcohol unit and an acrylic monomer unit and a polyvinylidene fluoride-based resin in a compatible state.
親水 The hydrophilic composite membrane according to claim 1, wherein the porous substrate has an average pore size of 1 nm to 4000 nm.
The hydrophilic composite membrane according to claim 1, wherein the porous substrate has a water contact angle of 85 to 130 degrees on one surface or both surfaces.
The hydrophilic composite membrane according to any one of claims 1 to 3, wherein the mass ratio of the vinyl alcohol unit in the water-insoluble copolymer is from 40% by mass to 90% by mass.
The hydrophilic composite film according to any one of claims 1 to 4, wherein the acrylic monomer unit contains at least one selected from the group consisting of a methacrylate unit and an acrylate unit.
The mass ratio of the water-insoluble copolymer and the polyvinylidene fluoride resin (the water-insoluble copolymer: the polyvinylidene fluoride resin) contained in the second hydrophilic material is 5:95 to 60:40. The hydrophilic composite membrane according to any one of claims 1 to 5, wherein
Further comprising a hydrophilic coating layer provided on one or both sides of the porous substrate,
7. The hydrophilic composite film according to claim 1, wherein the hydrophilic coating layer is at least one of a first hydrophilic coating layer and a second hydrophilic coating layer described below.
First hydrophilic coating layer: a hydrophilic coating layer containing a water-insoluble copolymer having a vinyl alcohol unit and an acrylic monomer unit.
Second hydrophilic coating layer: a hydrophilic coating layer containing a water-insoluble copolymer having a vinyl alcohol unit and an acrylic monomer unit and a polyvinylidene fluoride resin in a state of being compatible with each other.
The hydrophilic composite membrane according to claim 7, wherein the first hydrophilic coating layer or the second hydrophilic coating layer is a porous layer.
The hydrophilic composite membrane according to any one of claims 1 to 8, wherein the porous substrate is a polyolefin microporous membrane.
A polyvinylidene fluoride resin;
A water-insoluble copolymer having a vinyl alcohol unit and an acrylic monomer unit,
Is a hydrophilic porous membrane that is contained in a compatible state.
11. The hydrophilic porous membrane according to claim 10, wherein the mass ratio of the vinyl alcohol unit in the water-insoluble copolymer is from 40% by mass to 90% by mass.
The hydrophilic porous membrane according to claim 10 or 11, wherein the acrylic monomer unit includes at least one selected from the group consisting of a methacrylate unit and an acrylate unit.
The mass ratio of the polyvinylidene fluoride resin and the water-insoluble copolymer (the polyvinylidene fluoride resin: the water-insoluble copolymer) contained in the hydrophilic porous membrane is 40:60 to 95: 5. The hydrophilic porous membrane according to any one of claims 10 to 12.
A polyvinylidene fluoride resin;
A water-insoluble copolymer having a vinyl alcohol unit and an acrylic monomer unit,
Is a hydrophilic resin composition that is contained in a compatible state.
15. The hydrophilic resin composition according to claim 14, wherein a mass ratio of the vinyl alcohol unit in the water-insoluble copolymer is from 40% by mass to 90% by mass.
The hydrophilic resin composition according to claim 14 or 15, wherein the acrylic monomer unit contains at least one selected from the group consisting of a methacrylate unit and an acrylate unit.
The mass ratio of the polyvinylidene fluoride resin and the water-insoluble copolymer (the polyvinylidene fluoride resin: the water-insoluble copolymer) contained in the hydrophilic resin composition is 40:60 to 95: 5. The hydrophilic resin composition according to any one of claims 14 to 16, wherein