Emulsion, structure, and method for manufacturing the structure

Abstract

The present invention provides an emulsion capable of forming a structure having a porous membrane, a structure, and a method for manufacturing the structure. [Solution] The monomer units that make up the polymer are given by the following formula (1) TIFF2026070326000006.tif55132 (In the formula, R 1 R is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. 2 R is an alkylene group having 1 to 20 carbon atoms. 3 An emulsion containing a (meth)acrylic acid ester polymer as a dispersed phase, which includes monomer units derived from a silyl group-containing acrylic monomer represented by (where represents a hydrogen atom or a methyl group), and which is intended for use as a material for a structure having a porous membrane.

Description

[Technical Field]

[0001] The present invention relates to an emulsion, a structure formed using the emulsion, and a method for manufacturing the structure. [Background technology]

[0002] Research is progressing on structures equipped with porous membranes used as gas or liquid separation membranes, various filters, battery separators, filtration membranes, etc., as well as surface structures with minute irregularities and various foams. For example, a method for forming an emulsion coating film to create a uniform aqueous porous membrane by uniformly controlling heating in the thickness direction has been described (Patent Document 1). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-157276 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] Conventionally, porous films formed from emulsion coatings have primarily consisted of organic components. Such porous films lack heat resistance and durability. Therefore, there is a need for novel porous films with improved performance in these areas.

[0005] This invention has been made in view of the above circumstances, and aims to provide a novel emulsion capable of forming a structure having a porous membrane, the structure itself, and a method for manufacturing the structure. [Means for solving the problem]

[0006] To achieve the above objective, firstly, the present invention provides the following formula (1) as the monomer unit constituting the polymer [ka] (In the formula, R 1 R represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. 2 R represents an alkylene group with 1 to 20 carbon atoms. 3 The present invention provides an emulsion containing, as a dispersed phase, a (meth)acrylic acid ester polymer containing monomer units derived from a silyl group-containing acrylic monomer represented by ), which is intended for use as a material for a structure having a porous membrane (Invention 1).

[0007] In the above invention (Invention 1), it is preferable that the ratio of monomer units derived from the silyl group-containing acrylic monomer to the total monomer units constituting the (meth)acrylic acid ester polymer is 0.1 mol% or more and 10 mol% or less (Invention 2).

[0008] In the above inventions (Inventions 1 and 2), the particle size (D50) of the dispersed phase is preferably 10 nm or more and 1 μm or less (Invention 3).

[0009] In the above inventions (Inventions 1 to 3), it is preferable to include water as the dispersion medium (Invention 4).

[0010] Secondly, the present invention provides a structure comprising a porous membrane, characterized in that it is manufactured by a method comprising the steps of forming a coating film using the emulsion (Inventions 1 to 4) and forming the porous membrane by removing organic components from the coating film (Invention 5).

[0011] Thirdly, the present invention provides a method for manufacturing a structure having a porous membrane, characterized by comprising the steps of forming a coating film using the emulsion (Inventions 1 to 4) and forming the porous membrane by removing organic components from the coating film (Invention 6).

[0012] In the above invention (Invention 6), in the step of forming the porous film, it is preferable to remove the organic component from the coating film by performing at least one treatment selected from the group consisting of ultraviolet irradiation treatment, electron beam irradiation treatment, ion irradiation treatment, and plasma treatment (Invention 7).

Advantages of the Invention

[0013] The emulsion according to the present invention is a novel one capable of forming a structure provided with a porous film.

Brief Description of the Drawings

[0014] [Figure 1] It is an image of the surface of the resin layer according to Example 1. [Figure 2] It is an image of the surface of the resin layer according to Example 1 after oxygen plasma treatment. [Figure 3] It is an IR difference spectrum of the resin layer according to Example 1 before and after oxygen plasma treatment. [Figure 4] It is a diagram schematically showing the state in which the emulsion according to the present embodiment self-crosslinks.

Modes for Carrying Out the Invention

[0015] Hereinafter, embodiments of the present invention will be described. The emulsion according to the present embodiment contains, as a monomer unit constituting the polymer, a monomer unit derived from a silyl group-containing acrylic monomer represented by the following formula (1)

Chemical Formula

[0016] And the emulsion is for use as a material of a structure including a porous membrane.

[0017] As described above, the (meth)acrylate polymer in the present embodiment has a -Si—OR group in a monomer unit derived from a silyl group-containing acrylic monomer. 1 The (meth)acrylate polymer in the present embodiment stably exists as a dispersed substance in the state of an emulsion. On the other hand, when the emulsion according to the present embodiment is dried, the (meth)acrylate polymer has -Si—OR groups, and R—O—R is eliminated between the groups, and a siloxane bond (-Si—O—Si-) is formed. Therefore, when the emulsion according to the present embodiment is dried, self-crosslinking of the (meth)acrylate polymer proceeds. As a result, a desired coating film can be formed, which has an inorganic component of a siloxane bond (-Si—O—Si-) and an organic component of the (meth)acrylate polymer and shows a specific morphology reflecting the particle diameter of the emulsion. The coating film is usually formed by applying the above emulsion to the surface of a predetermined object, and the above specific morphology appears particularly prominently on the surface side of the predetermined object.

[0018] FIG. 4 is a diagram schematically showing the above-described self-crosslinking. The (meth)acrylate polymer shown here contains acrylic acid together with the above-described silyl group-containing acrylic monomer as a monomer unit constituting the polymer. Therefore, in the schematic diagram surrounded by the frame on the left side in the figure, a silanol group (-Si-OH) derived from the silyl group-containing acrylic monomer and a carboxy group (ammonium salt) derived from acrylic acid exist on the surface of the emulsion. Then, by drying the emulsion under the conditions of 100° C. for 2 minutes, water molecules (H2O) are eliminated from the silanol group, and a siloxane bond (-Si—O—Si-) is formed. As a result, a structure in which the emulsions are integrated is formed as in the schematic diagram surrounded by the frame on the right side in the figure.

[0019] ​​​​​​Furthermore, as confirmed in the test examples described later, the above coating film exhibits a relatively high gel fraction. Here, the gel fraction of the coating film obtained by drying the emulsion according to this embodiment is preferably 85% or more and 90% or more. Details of the method for measuring the gel fraction are described in Test Example 1, which will be described later. In addition, the water contact angle of the coating film obtained by drying the emulsion according to this embodiment is preferably 90°C or more and 120°C or less. Details of the test method for the water contact angle are described in Test Example 2, which will be described later.

[0020] Furthermore, by performing a treatment to remove organic components from the above coating film, a porous film mainly composed of residual inorganic components can be obtained, as confirmed in the test examples described later. A porous film mainly composed of inorganic components has improved heat resistance and durability compared to a porous film containing a large amount of organic components. This porous film is expected to be used as a separator for batteries, a filtration film, and as a template for forming surface structures with minute irregularities.

[0021] 1. Emulsion (1) (meth)acrylic acid ester polymer The (meth)acrylic acid ester copolymer in this embodiment is not particularly limited as long as it contains a silyl group-containing acrylic monomer represented by the above formula (1) as a monomer unit constituting the polymer.

[0022] In the silyl group-containing acrylic monomer represented by the above formula (1), as described above, R 1 R represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, but the number of carbon atoms in the alkyl group is preferably 1 to 5, and particularly preferably 1 to 3. From the viewpoint of efficiently forming the siloxane bond mentioned above, 1 It is preferable that this is a hydrogen atom or a methyl group.

[0023] Also, R 2As mentioned above, this represents an alkylene group having 1 to 20 carbon atoms, but the number of carbon atoms in the alkylene group is preferably 1 to 10, and particularly preferably 1 to 5. From the viewpoint of efficiently forming the siloxane bond mentioned above, R 2 It is preferable that it be a propylene group.

[0024] Furthermore, R 3 As mentioned above, this represents a hydrogen atom or a methyl group.

[0025] Examples of silyl group-containing acrylic monomers represented by the above formula (1) include 3-methacryloyloxypropyltrimethoxysilane, 3-acryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropyltriethoxysilane, 3-acryloyloxypropyltriethoxysilane, 3-methacryloyloxypropylmethyldimethoxysilane, 3-acryloyloxypropylmethyldimethoxysilane, 3-methacryloyloxypropylmethyldiethoxysilane, and 3-acryloyl Examples include oxypropylmethyldiethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 4-vinylbutyltrimethoxysilane, 4-vinylbutyltriethoxysilane, 8-vinyloctyltrimethoxysilane, 8-vinyloctyltriethoxysilane, 10-methacryloyloxydecyltrimethoxysilane, 10-acryloyloxydecyltrimethoxysilane, 10-methacryloyloxydecyltriethoxysilane, and 10-acryloyloxydecyltriethoxysilane. These silyl group-containing acrylic monomers can be used individually or in combination of two or more.

[0026] In this embodiment, the ratio of monomer units derived from the silyl group-containing acrylic monomer to the total monomer units constituting the (meth)acrylic acid ester polymer is preferably 0.1 mol% or more, particularly preferably 0.5 mol% or more, and even more preferably 1 mol% or more. A ratio of 0.1 mol% or more facilitates the efficient formation of the aforementioned siloxane bonds. Furthermore, a ratio of 10 mol% or less is preferable, particularly preferable 5 mol% or less, and even more preferably 3 mol% or less. A ratio of 10 mol% or less ensures a sufficient proportion of monomer units other than those derived from the silyl group-containing acrylic monomer, making it easier for the emulsion preparation and the resulting coating film and porous film to have the desired performance.

[0027] The (meth)acrylic acid ester copolymer in this embodiment may contain monomers other than the silyl group-containing acrylic monomers described above as monomer units constituting the polymer. For example, examples of such other monomers include alkyl (meth)acrylic acid esters with alkyl groups having 1 to 12 carbon atoms; monomers containing reactive functional groups such as hydroxyl groups, carboxyl groups, and amino groups; alkoxyalkyl group-containing (meth)acrylic acid esters; (meth)acrylic acid esters having aromatic rings such as phenyl (meth)acrylate; non-crosslinked acrylamides such as acrylamide and methacrylamide; non-crosslinked (meth)acrylic acid esters having tertiary amino groups such as N,N-dimethylaminoethyl (meth)acrylate and N,N-dimethylaminopropyl (meth)acrylate; vinyl acetate; styrene, etc. These may be used individually or in combination of two or more.

[0028] Among the above, it is preferable that the (meth)acrylic acid ester copolymer in this embodiment contains butyl acrylate as a monomer unit constituting the polymer. The inclusion of butyl acrylate in the (meth)acrylic acid ester copolymer makes it easier to adjust properties such as gel fraction and tackiness. Furthermore, it is also preferable that the (meth)acrylic acid ester copolymer in this embodiment contains acrylic acid as a monomer unit constituting the polymer. The inclusion of acrylic acid in the (meth)acrylic acid ester copolymer makes it easier to adjust the particle size of the (meth)acrylic acid ester copolymer as a dispersed phase.

[0029] In the emulsion according to this embodiment, the particle size (D50) of the dispersed phase, which is composed of a (meth)acrylic acid ester copolymer, is preferably 10 nm or more, particularly preferably 50 nm or more, and even more preferably 80 nm or more. Furthermore, the particle size (D50) is preferably 1 μm or less, particularly preferably 500 nm or less, and even more preferably 200 nm or less. Having the particle size (D50) of the dispersed phase within the above range makes it easier to form the desired pores when forming a porous film. Details of the method for measuring the particle size (D50) are described in the examples below.

[0030] (2) Dispersion medium In the emulsion according to this embodiment, the dispersion medium is not particularly limited as long as it can disperse the (meth)acrylic acid ester copolymer as the dispersion phase. However, from the viewpoint of reducing the amount of residual organic solvent in the coating film or porous film formed using the emulsion according to this embodiment, it is preferable that the emulsion according to this embodiment contains water as the dispersion medium.

[0031] (3) Method for producing emulsion Although the method for producing the emulsion according to this embodiment is not particularly limited, it is preferable to emulsion polymerize monomer units containing the silyl group-containing acrylic monomers described above to obtain an emulsion containing a (meth)acrylic acid ester copolymer as a dispersed phase.

[0032] Conventional emulsion polymerization methods can be used as described above. For example, emulsion polymerization can be carried out by stirring the aforementioned silyl group-containing acrylic monomer, optionally other monomers, and an emulsifier in water as a dispersion medium, then adding a polymerization initiator and stirring at a predetermined temperature.

[0033] While there are no particular restrictions on the emulsifier used, anionic or nonionic emulsifiers are preferred, and anionic emulsifiers are more preferred, from the viewpoint of improving dispersion stability.

[0034] Examples of anionic emulsifiers include sodium lauryl sulfate, ammonium lauryl sulfate, sodium dodecylbenzenesulfonate, sodium polyoxyethylene alkyl ether sulfate, sodium polyoxyethylene alkylphenyl ether sulfate, polyoxyethylene polycyclic phenyl ether sulfate, sodium polyoxyethylene alkyl ether sulfate, and allyl alkyl sulfosuccinate. Examples of nonionic emulsifiers include polyoxyethylene alkyl ether and polyoxyethylene alkylphenyl ether. Among these, polyoxyethylene polycyclic phenyl ether sulfate is particularly preferred. These emulsifiers may be used individually or in combination of two or more.

[0035] Regarding the emulsifier content, from the viewpoint of stability of the emulsion polymerization reaction and from the viewpoint of preventing deterioration of physical properties due to the presence of unreacted emulsifier, it is preferable that it be 1 part by mass or more, particularly preferably 3 parts by mass or more, and more preferably 5 parts by mass or more, per 100 mass of the total amount of monomers. Furthermore, the emulsifier content is preferably 30 parts by mass or less, particularly preferably 25 parts by mass or less, and more preferably 20 parts by mass or less, per 100 mass of the total amount of monomers.

[0036] The polymerization initiators mentioned above may be water-soluble or oil-soluble. Examples include azo compounds such as 2,2'-azobis(2-methylpropionamidine) dihydrochloride and 2,2'-azobis(2-amidinopropane) dihydrochloride, persulfates such as potassium persulfate, sodium persulfate, and ammonium persulfate, and peroxides such as benzoyl peroxide, t-butyl hydroperoxide, and hydrogen peroxide. Redox initiators consisting of combinations of persulfates and sodium bisulfite, or combinations of peracids and sodium ascorbate, may also be used. The polymerization initiators may be used alone or in combination of two or more. Among these, ammonium persulfate is preferred from the viewpoint of excellent polymerization stability. These polymerization initiators may be used alone or in combination of two or more.

[0037] From the viewpoint of accelerating the polymerization rate, the polymerization initiator content is preferably 0.1 parts by mass or more, particularly preferably 0.5 parts by mass or more, and even more preferably 1 part by mass or more, per 100 mass of the total amount of monomers. Furthermore, the polymerization initiator content is preferably 10 parts by mass or less, particularly preferably 7 parts by mass or less, and even more preferably 5 parts by mass or less, per 100 mass of the total amount of monomers.

[0038] The temperature and stirring conditions after adding the polymerization initiator or monomer are as long as they allow the dispersed phase to disperse sufficiently. For example, the temperature is preferably 60 to 90°C, more preferably 65 to 85°C, and even more preferably 70 to 80°C. The stirring speed is preferably 50 to 200 rpm, more preferably 70 to 180 rpm, and even more preferably 100 to 150 rpm. The stirring time is preferably 10 to 180 minutes, more preferably 10 to 60 minutes, and even more preferably 10 to 30 minutes.

[0039] Furthermore, it is preferable to adjust the pH of the emulsion obtained by emulsion polymerization to 5-9 by adding ammonia water, various water-soluble amines, sodium hydroxide aqueous solution, potassium hydroxide aqueous solution, etc., and it is particularly preferable to adjust it to 6-8.5. This makes it possible to improve the stability of the dispersion.

[0040] The solid content concentration of the resulting emulsion is preferably 10 to 80% by mass, more preferably 25 to 70% by mass, and even more preferably 45 to 65% by mass.

[0041] 2. Structures comprising a porous membrane As described above, the emulsion according to this embodiment is intended for use as a material for a structure having a porous membrane. This structure can be manufactured by a method comprising the steps of forming a coating film using the emulsion according to this embodiment and forming the porous membrane by removing organic components from the coating film.

[0042] In the process of forming the coating film described above, the coating film can be formed by applying an emulsion to a predetermined object. The coating film can be dried as needed. This drying process may involve exposing the film to a temperature of 80 to 120°C, preferably 90 to 110°C, for 0.5 to 15 minutes, preferably 1 to 5 minutes.

[0043] Specific examples of the specified targets mentioned above include glass, paper, synthetic paper, plastic resin, metal, ceramic, semiconductor wafer, semiconductor substrate, and other supports, and these supports may be release supports. In the case of release supports, a release agent layer may be provided on the surface. These supports may be laminated. Examples of plastic resins include general-purpose plastic sheets such as polyolefin resins such as polystyrene, polyethylene, and polypropylene, and polyester resins such as polyethylene terephthalate, as well as engineering plastics such as polyimide resin, ABS resin, and polycarbonate resin. Examples of metals include aluminum and copper. A vapor-deposited layer of metal or the like may be formed on the surface of these supports. Furthermore, when coating these supports, corona treatment or the like may be performed to improve wettability.

[0044] Furthermore, in the process of forming the porous film described above, the treatment for removing organic components is not particularly limited, but is preferably at least one treatment selected from the group consisting of ultraviolet irradiation, electron beam irradiation, ion irradiation and plasma treatment, heat treatment, radiation irradiation and ultraviolet ozone (UV ozone) irradiation. By performing these treatments, organic components can be selectively removed.

[0045] Among the methods described above, plasma treatment is preferred. Although this plasma treatment can be carried out under general conditions, it is preferable to use oxygen, argon, methane, ammonia, nitrogen, or combinations thereof as the gas, and oxygen is particularly preferred.

[0046] The structure comprising the porous film according to this embodiment is obtained by removing organic components from a coating film formed from the emulsion according to this embodiment. Therefore, in the structure according to this embodiment, silicon dioxide components derived from silyl group-containing acrylic monomers remain. It is expected that the framework of the porous film is mainly formed by these silicon dioxide components.

[0047] The embodiments described above are provided to facilitate understanding of the present invention and are not intended to limit it. Accordingly, each element disclosed in the above embodiments is intended to include all design modifications and equivalents that fall within the technical scope of the present invention. [Examples]

[0048] The present invention will be described in more detail below with reference to examples, but the scope of the present invention is not limited to these examples.

[0049] [Example 1] 1. Preparation of emulsion 94.5 parts by mass of butyl acrylate as monomer, 5.0 parts by mass of acrylic acid, and 0.5 parts by mass of 3-methacryloxypropyltrimethoxysilane "KBM-503" (manufactured by Shin-Etsu Chemical Co., Ltd.) were added to 150 parts by mass of purified water along with 1.0 part by mass of polyoxyethylene polycyclic phenyl ether sulfate salt (manufactured by Nippon Emulsifier Co., Ltd., product name "Newcol 707SF") as an emulsifier, and the mixture was heated to 70°C while stirring.

[0050] Furthermore, 3-methacryloxypropyltrimethoxysilane corresponds to the silyl group-containing acrylic monomer represented by formula (1) above, and in particular, in formula (1), R 1 is a methyl group, R 2 The propylene group is R 3 This corresponds to a silyl group-containing acrylic monomer, which is a methyl group.

[0051] To purified water containing the above monomer and emulsifier, 0.3 parts by mass of ammonium persulfate as a polymerization initiator was added and stirred to allow copolymerization by emulsion polymerization. This yielded an emulsion in which the (meth)acrylic acid ester polymer was dispersed as the dispersed phase in water as the dispersion medium.

[0052] As described above, the particle size distribution of the dispersed phase was measured using dynamic light scattering (DLS) and found that the average particle size (D50) was 126 nm.

[0053] 2. Preparation of resin sheets The emulsion obtained in step 1 above was applied to the side of the easy-adhesion layer of a polyethylene terephthalate film (manufactured by Toyobo Co., Ltd., product name "PET4160", thickness: 50 μm) with an easy-adhesion layer using an applicator. The resulting coated layer was then heat-treated at 100°C for 1 minute to form a resin layer. The thickness of this resin layer was measured to be 15 μm.

[0054] Next, the resin layer side of the laminate of the process sheet and resin layer obtained above was laminated to the release-treated surface of a lightweight release sheet (Lintec Corporation, product name "SP-PET381031"), which was obtained by releasing one side of a polyethylene terephthalate film with a silicone-based release agent. This resulted in a resin sheet consisting of an easy-to-adhere PET sheet, a resin layer (thickness: 15 μm), and a lightweight release sheet.

[0055] The thickness of the resin layer was measured in accordance with JIS K7130 using a constant-pressure thickness measuring instrument (TECLOCK Co., Ltd., product name "PG-02").

[0056] [Example 2] An emulsion and a resin sheet were obtained in the same manner as in Example 1, except that the composition of monomers added to purified water was changed to 93.0 parts by mass of butyl acrylate, 5.0 parts by mass of acrylic acid, and 2.0 parts by mass of 3-methacryloxypropyltrimethoxysilane.

[0057] Furthermore, when the particle size distribution of the dispersed phase of the emulsion obtained as described above was measured by dynamic light scattering (DLS), the average particle size (D50) was found to be 143 nm.

[0058] [Comparative Example 1] An emulsion and a resin sheet were obtained in the same manner as in Example 1, except that the composition of monomers added to purified water was changed to 95.0 parts by mass of butyl acrylate and 5.0 parts by mass of acrylic acid.

[0059] Furthermore, when the particle size distribution of the dispersed phase of the emulsion obtained as described above was measured by dynamic light scattering (DLS), the average particle size (D50) was found to be 143 nm.

[0060] [Test Example 1] (Measurement of gel fraction) The resin sheets prepared in the examples and comparative examples were cut to a size of 80 mm x 80 mm, and the resin layer was wrapped in a polyester mesh (mesh size 200). The mass was weighed using a precision balance, and the mass of the resin layer alone was calculated by subtracting the mass of the mesh alone. This mass is denoted as M1.

[0061] Next, the resin layer wrapped in the polyester mesh was immersed in ethyl acetate at room temperature (23°C) for 72 hours. After that, the resin layer was removed and air-dried for 24 hours at 23°C and 50% relative humidity, and then dried in an oven at 80°C for 12 hours. After drying, its mass was weighed using a precision balance, and the mass of the resin layer alone was calculated by subtracting the mass of the mesh alone. This mass is denoted as M2.

[0062] Based on the M1 and M2 values ​​obtained above, the gel fraction (%) was calculated using the formula (M2 / M1) × 100. The results are shown in Table 1.

[0063] [Test Example 2] (Contact Angle) The water contact angle on the resin layer surface of the resin sheets manufactured in the examples and comparative examples was measured using a contact angle meter (Kyowa Interface Science Co., Ltd., product name "DM-701") under the following conditions. The results are shown in Table 1. • Amount of water droplets: 2 μl ·Measurement time: 3 seconds after dropping • Image analysis method: θ / 2 method

[0064] [Test Example 3] (Oxygen Plasma Treatment) The emulsions prepared in the examples and comparative examples were applied to a soda-lime glass substrate and heated at 100°C for 1 minute to form a resin layer.

[0065] Images of the glass contact surface and the opposite surface (air contact surface) of the resin layer were taken using atomic force microscopy (AFM). Figure 1 shows the results of Example 1 from the images taken. In Figure 1, the left side is the image of the air contact surface, and the right side is the image of the glass contact surface.

[0066] Next, the resin layer provided on the soda-lime glass substrate was subjected to oxygen plasma treatment under the following conditions. <Oxygen plasma treatment conditions> Output: 250W Gas: Oxygen (O2) Gas flow rate: 10 ccm Processing time: 180 seconds

[0067] Surface images of the resin layer after oxygen plasma treatment were also taken using the AFM method, similar to the method described above. Figure 2 shows the results of Example 1 from the images taken. In Figure 2, the left side is the image of the air contact surface, and the right side is the image of the glass contact surface.

[0068] Furthermore, Table 1 shows the results, with "○" indicating that porous film formation was confirmed by surface imaging using AFM, and "×" indicating that it was not confirmed.

[0069] Furthermore, Fourier transform infrared spectroscopy (FT-IR) was used to measure the IR difference spectrum of the resin layer before and after oxygen plasma treatment. Specifically, using the analysis software provided with the instrument, a coefficient was set to cancel out common peak intensities, and the FT-IR difference spectrum was obtained by subtracting the pre-oxygen plasma treatment spectrum from the post-oxygen plasma treatment spectrum and confirming the intensity of the peak originating from the siloxane bond (-Si-O-Si-). The results are shown in Figure 3.

[0070] [Table 1]

[0071] As shown in Table 1, it was found that a resin sheet exhibiting a high gel fraction can be formed by using the emulsion according to the example.

[0072] Furthermore, Figures 1 and 2 show that a porous film with fine pores can be formed by using the emulsion according to the example. In particular, Figure 1 shows that when the emulsion according to the example is dried, self-crosslinking of the (meth)acrylic acid ester polymer proceeds, and it can be confirmed that it has an inorganic component of siloxane bonds (-Si-O-Si-) (the white area around the particles on the right side (b) of Figure 1) and an organic component of the (meth)acrylic acid ester polymer (the gray area inside the particles on the right side (b) of Figure 1), and exhibits a unique morphology that reflects the particle size of the emulsion. Also, Figure 2 shows that the surface of the resin layer after oxygen plasma treatment has had the organic component removed and has formed a porous film in which the inorganic component of siloxane bonds (-Si-O-Si-) mainly remains. In particular, Figure 3 shows that the oxygen plasma treatment generates a peak due to the -O-Si-O- structure, indicating that a condensation reaction proceeded in the monomer units derived from 3-methacryloxypropyltrimethoxysilane. [Industrial applicability]

[0073] The emulsion of the present invention can be suitably used as a material for structures having a porous membrane. Such structures can also be used as templates for forming surface structures having minute irregularities.

Claims

1. The monomer units that make up the polymer are given by the following formula (1) 【Chemistry 1】 (In the formula, R １ R represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. ２ R represents an alkylene group with 1 to 20 carbon atoms. ３ An emulsion containing a (meth)acrylic acid ester polymer as a dispersed phase, which includes monomer units derived from a silyl group-containing acrylic monomer represented by , where represents a hydrogen atom or a methyl group. An emulsion characterized for use as a material for structures having a porous membrane.

2. The emulsion according to claim 1, characterized in that the ratio of monomer units derived from the silyl group-containing acrylic monomer to the total monomer units constituting the (meth)acrylic acid ester polymer is 0.1 mol% or more and 10 mol% or less.

3. The emulsion according to claim 1, characterized in that the particle size (D50) of the dispersed phase is 10 nm or more and 1 μm or less.

4. The emulsion according to claim 1, characterized in that it contains water as a dispersion medium.

5. A structure comprising a porous membrane, A step of forming a coating film using the emulsion described in any one of claims 1 to 4, The process of forming the porous film by removing organic components from the aforementioned coating film, A structure characterized by being manufactured by a method comprising the following.

6. A step of forming a coating film using the emulsion described in any one of claims 1 to 4, The process of forming the porous film by removing organic components from the aforementioned coating film, A method for manufacturing a structure comprising a porous membrane, characterized by comprising the following:

7. The manufacturing method according to claim 6, characterized in that, in the step of forming the porous film, the organic component is removed from the coating film by performing at least one treatment selected from the group consisting of ultraviolet irradiation, electron beam irradiation, ion irradiation, and plasma treatment.

Images