TW202235452A - Vinyl-based resin particles - Google Patents

Abstract

To provide novel vinyl-based resin particles that have excellent dispersion stability and solvent resistance for organic solvents, suppress aggregate generation and gelation, and are capable of forming fine, uniform pores in a film of a thermosetting resin, etc. Vinyl-based resin particles that are a polymer having a structural unit (A) derived from a vinyl-based monomer and a structural unit (b1) derived from a compound represented by general formula (I) different from the structural unit (A), to be used to make a thermosetting resin porous. [In the formula, m represents an integer of 1-3, R represents a polymerizable unsaturated group, AO represents a C2-4 alkyleneoxy group, n represents an integer of 0-100, X represents a hydrogen atom or an anionic hydrophilic group selected from the group consisting of -SO3M, -COOM, and -PO3M (in the formula, M represents an alkali metal atom, an alkaline earth metal atom, an ammonium group, or an organic ammonium group.).].

Description

Vinyl resin particles

The present invention relates to vinyl-based resin particles, and more specifically, to vinyl-based resin particles for producing porous membranes used for porous thermosetting resins and the like.

In recent years, polyimide and/or polyamideimide are being used as filters for gas or liquid separation membranes, or as separators for lithium-ion batteries, fuel cell electrolyte membranes, or low dielectric constant materials. Research on porous membranes. For example, as a method for producing a polyimide porous membrane used in a separator, it is known to disperse fine particles such as silica particles in a polymer solution of polyamic acid or polyimide After the paint is coated on the substrate, if necessary, the coating film is heated to obtain a polyimide film containing fine particles, and then, the fine particles such as silicon dioxide particles in the polyimide film are removed with hydrofluoric acid, and a method of making it porous (refer to Patent Document 1).

When forming a porous polyimide film by the method described in Patent Document 1, etc., it is desirable to use a coating material having a uniformly dispersed composition to form a coating film having a uniform thickness or composition. However, the handling of hydrofluoric acid using the production method described in Patent Document 1 is generally not easy. Therefore, the use of hydrofluoric acid has become a factor that increases the production cost of polyimide porous membranes, and a method of producing porous membranes without using hydrofluoric acid has been sought. For example, it is considering changing the above-mentioned silica particles to use other fine particles such as organic fine particles. [Prior Art Literature] [Patent Document]

[Patent Document 1] Japanese Patent No. 5605566

[Problem to be solved by the invention]

However, organic fine particles are often prepared in an aqueous medium, and are often circulated as a fine particle dispersion containing water. Therefore, when preparing a paint containing polyamic acid or polyimide by using a fine particle dispersion liquid containing water by using organic fine particles, it is inevitable to obtain a paint containing water. When the above-mentioned paint contains water and fine particles, the compatibility between the polyamic acid and the solvent containing water is poor, or the alignment of the polyamic acid is hindered by the existence of the fine particles, and it becomes a block containing polyamic acid surrounding the fine particles There is a problem of easily forming a mixture of non-uniform composition which may cause poor formation of a coating film, which may lead to a decrease in film strength.

In order to avoid such problems, it is considered to use completely dried organic fine particles to produce a paint that does not substantially contain water. However, the dispersion stability or solvent resistance of the dried organic microparticles to the organic solvent in which polyamic acid is dissolved is not good, and aggregates are formed, making it difficult to obtain a polyimide porous film with uniform pores and good air permeability. And so on.

The present invention has been made in view of the above-mentioned problems to provide a uniform and fine void that has excellent dispersion stability and solvent resistance to organic solvents, suppresses the generation of aggregates or gelation, and can form a film of thermosetting resin. Novel vinyl resin particles with holes are the purpose. [Means to solve the problem]

[式中， m表示1～3之整數， R表示下述式(i)或式(ii)表示之基，

(式中，R ₁表示氫原子或甲基)， AO表示碳原子數2～4之乙烯氧基，n表示0～100之整數， X表示氫原子，或表示選自由-SO ₃M、-COOM及    -PO ₃M(式中，M表示鹼金屬原子、鹼土類金屬原子、銨基或有機銨基)所構成之群組中之陰離子性親水基]。 [3] 如[2]所記載之乙烯系樹脂粒子，其中，前述構造單位(b1)的比例相對於前述聚合物之前述構造單位的合計質量，為0.1質量%～2.0質量%。 [4] 如[2]或[3]所記載之乙烯系樹脂粒子，其中，前述源自乙烯系單體之構造單位(A)包含源自單官能乙烯系單體之構造單位(A1)與源自多官能乙烯系單體之構造單位(A2)。 [5] 如[1]至[4]當中任一項所記載之乙烯系樹脂粒子，其中，樹脂粒子之中位徑為0.05μm～2.0μm。 [6] 如[1]、[4]或[5]所記載之乙烯系樹脂粒子，其中，前述源自單官能乙烯系單體之構造單位(A1)包含源自單官能苯乙烯系單體之構造單位(a1)。 [7] 如[1]及[4]至[6]當中任一項所記載之乙烯系樹脂粒子，其中，前述源自單官能乙烯系單體之構造單位(A1)包含源自單官能(甲基)丙烯醯基系單體之構造單位(a2)。 [8] 如[1]及[4]至[7]當中任一項所記載之乙烯系樹脂粒子，其中，前述多官能乙烯系單體(A2)的比例相對於前述聚合物之前述構造單位的合計質量，為0.9質量%～10質量%。 [9] 一種乙烯系樹脂粒子水性分散體之製造方法，其特徵為於水性分散媒中，聚合起始劑的存在下， 乳化聚合乙烯系單體、與和前述乙烯系單體不同之下述一般式(I)表示之化合物。

[式中， m表示1～3之整數， R表示下述式(i)或式(ii)表示之基，

(式中，R ₁表示氫原子或甲基)， AO表示碳原子數2～4之乙烯氧基，n表示0～100之整數， X表示氫原子，或選自由-SO ₃M、-COOM及-PO ₃M(式中，M表示鹼金屬原子、鹼土類金屬原子、銨基或有機銨基)所構成之群組中之陰離子性親水基]。 [發明效果] The present invention is aimed at the following [1] to [9]. [1] A vinyl resin particle for producing a porous membrane, which has a structural unit (A1) derived from a monofunctional vinyl monomer, a structural unit (A2) derived from a polyfunctional vinyl monomer, and a structural unit derived from a reaction Vinyl-based resin particles for producing porous membranes of polymers of the structural unit (B) of the emulsifier, characterized in that the proportion of the structural unit (A1) is 88 to 99% by mass, and the proportion of the structural unit (A2) is 0.9-10 mass %, and the ratio of the said structural unit (B) is 0.1-2 mass %. [2] A vinyl resin particle for producing a porous membrane, which has a structural unit (A) derived from a vinyl monomer and is represented by the following general formula (I) derived from the structural unit (A) different from the aforementioned The polymer of the structural unit (b1) of the compound.

[wherein, m represents an integer of 1 to 3, R represents a group represented by the following formula (i) or formula (ii),

(wherein, R ₁ represents a hydrogen atom or a methyl group), AO represents an ethyleneoxy group with 2 to 4 carbon atoms, n represents an integer from 0 to 100, X represents a hydrogen atom, or represents a group selected from -SO ₃ M, - An anionic hydrophilic group in the group consisting of COOM and -PO ₃ M (wherein, M represents an alkali metal atom, an alkaline earth metal atom, an ammonium group or an organic ammonium group)]. [3] The vinyl resin particle according to [2], wherein the proportion of the structural unit (b1) is 0.1% by mass to 2.0% by mass relative to the total mass of the structural units of the polymer. [4] The vinyl resin particle as described in [2] or [3], wherein the structural unit (A) derived from a vinyl monomer includes a structural unit (A1) derived from a monofunctional vinyl monomer and A structural unit (A2) derived from a polyfunctional vinyl monomer. [5] The vinyl resin particles according to any one of [1] to [4], wherein the median diameter of the resin particles is 0.05 μm to 2.0 μm. [6] The vinyl resin particle as described in [1], [4] or [5], wherein the structural unit (A1) derived from a monofunctional vinyl monomer contains The structural unit (a1). [7] The vinyl resin particle as described in any one of [1] and [4] to [6], wherein the structural unit (A1) derived from a monofunctional vinyl monomer includes a monofunctional ( Structural unit (a2) of a meth)acryl-based monomer. [8] The vinyl resin particle as described in any one of [1] and [4] to [7], wherein the ratio of the polyfunctional vinyl monomer (A2) to the structural unit of the polymer is The total mass of is 0.9% by mass to 10% by mass. [9] A method for producing an aqueous dispersion of vinyl resin particles, characterized in that, in an aqueous dispersion medium, in the presence of a polymerization initiator, a vinyl monomer, different from the aforementioned vinyl monomer, is emulsified and polymerized: A compound represented by the general formula (I).

[wherein, m represents an integer of 1 to 3, R represents a group represented by the following formula (i) or formula (ii),

(wherein, R ₁ represents a hydrogen atom or a methyl group), AO represents an ethyleneoxy group with 2 to 4 carbon atoms, n represents an integer from 0 to 100, X represents a hydrogen atom, or is selected from -SO ₃ M, -COOM and -PO ₃ M (wherein, M represents an anionic hydrophilic group in the group consisting of an alkali metal atom, an alkaline earth metal atom, an ammonium group or an organic ammonium group]]. [Invention effect]

The vinyl resin particles of the present invention are mixed with an organic solvent that dissolves a thermosetting resin (such as the precursor of a polyimide resin, that is, polyamic acid), to inhibit the generation of aggregates, or to gel or increase the viscosity, It has mixing stability, and can suppress the dissolution or shape change of particles in an organic solvent, and can be excellent in solvent resistance. Therefore, when the vinyl resin particle of the present invention is used as a porous material of a thermosetting resin, even in a mixture with a thermosetting resin material, it is difficult to dissolve or aggregate particles. The membrane can easily form uniform and fine pores, and can produce a porous body (porous membrane).

[vinyl resin particles]

In the present invention, the structural unit (A) derived from a vinyl monomer and the structural unit (b1) derived from a compound represented by the general formula (I) described below are essential polymers, namely vinyl resin particles. . That is, the vinyl resin particle (polymer) of the present invention can be constituted by each of the above-mentioned structural units, and can be a copolymer ( Copolymer). The vinyl resin particles of the present invention can be suitably used as a porous material of a thermosetting resin, that is, can be suitably used as vinyl resin particles for porous film production.

In addition, the present invention has a structural unit (A1) derived from a monofunctional vinyl monomer described later, a structural unit (A2) derived from a polyfunctional vinyl monomer described later, and a structural unit derived from The polymer of the structural unit (B) of the reactive emulsifier described later, ie, vinyl resin particles, was used as an object.

Also, in this specification, the (meth)acryl-based monomer refers to both the acryl-based monomer and the methacryl-based monomer. For example, alkyl (meth)acrylate refers to alkyl acrylate and alkyl methacrylate. Also, in this specification, "a structural unit derived from a vinyl monomer", "a structural unit derived from a monofunctional styrene monomer", and "a structural unit derived from a monofunctional (meth)acryl monomer" Expressions such as "structural units derived from polyfunctional vinyl monomers" are vinyl monomers, monofunctional styrene monomers, monofunctional (meth)acryl monomers, and polyfunctional vinyl monomers Indicates the structural units formed when they are separately polymerized, not the monomers themselves.

[Structural unit (A) derived from vinyl monomer] The polymer of the vinyl resin particles of the present invention has a structural unit (A) derived from a vinyl monomer. The aforementioned structural unit (A) is divided into a structural unit (B) derived from a reactive emulsifier described later and a structural unit (b1) derived from a compound represented by general formula (I). The aforementioned structural unit (A) may include a structural unit (A1) derived from a monofunctional vinyl monomer and a structural unit (A2) derived from a polyfunctional vinyl monomer, and a structure derived from a monofunctional vinyl monomer The unit (A1) may contain a structural unit (a1) derived from a monofunctional styrene-based monomer or a structural unit (a2) derived from a monofunctional (meth)acryl-based monomer. In a suitable aspect, the structural unit (A) includes both the structural unit (A1) derived from a monofunctional vinylic monomer and the structural unit (A2) derived from a polyfunctional vinylic monomer.

[Constructive unit (A1) derived from monofunctional vinyl monomer] <Constructive unit (a1) derived from monofunctional styrenic monomer> As the structural unit (A1) derived from a monofunctional vinylic monomer, a structural unit (a1) derived from a monofunctional styrene monomer may be contained. Building blocks derived from styrenic monomers can contribute to uniform true spherical particle formation.

上述式中，R _a1表示碳原子數1至10之烷基、       -S(O) ₂OM ₁，前述M ₁表示鹼金屬原子、第2族金屬原子、銨基或有機銨基。 又，p表示0或1～5之整數，複數個R _a1可分別相同亦可為相異)。 Although it is not limited as said structural unit (a1), the structural unit represented by the following formula is mentioned, for example.

In the above formula, R _a1 represents an alkyl group having 1 to 10 carbon atoms, -S(O) ₂ OM ₁ , and the aforementioned M ₁ represents an alkali metal atom, a Group 2 metal atom, an ammonium group or an organic ammonium group. Also, p represents 0 or an integer of 1 to 5, and a plurality of R _a1 may be the same or different).

Examples of the monofunctional styrenic monomer constituting the structural unit (a1) include styrene, α-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2,4-di Styrene and its derivatives such as methylstyrene, 2,5-dimethylstyrene, 2,4,6-trimethylstyrene; styrene such as sodium styrene sulfonate and ammonium styrene sulfonate Sulfonate. Among these, styrene, (alpha)-methylstyrene, and sodium styrenesulfonate are mentioned suitably.

<Constructive unit (a2) derived from monofunctional (meth)acryl-based monomer> In addition, as the structural unit (A1) derived from a monofunctional vinylic monomer, in addition to the structural unit (a1) derived from a monofunctional styrene monomer, a monofunctional (meth)acryl-derived The structural unit (a2) of the basic monomer. Structural units derived from (meth)acryl-based monomers have the characteristics of being easy to decompose (depolymerize) as monomer units regardless of monofunctionality or polyfunctionality, and have excellent thermal decomposition properties, and can reduce the ethylene content of the present invention. The thermal decomposition temperature of the resin particles.

上述式中，R _a21、R _a22、R _a23分別獨立表示氫原子或甲基，R _a24表示氫原子、碳原子數1至10之烷基。 Although it is not limited as said structural unit (a2), the structural unit represented by the following formula is mentioned, for example.

In the above formula, R _a21 , R _a22 , and R _a23 each independently represent a hydrogen atom or a methyl group, and R _a24 represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms.

Examples of the monofunctional (meth)acryl-based monomer constituting the structural unit (a2) include methyl (meth)acrylate, ethyl (meth)acrylate, and n-propyl (meth)acrylate. , Isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, n-pentyl (meth)acrylate, ( 3-methylbutyl methacrylate, n-hexyl (meth)acrylate, cyclohexyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, (meth)acrylates having 1 to 18 carbon atoms in the alkyl group, such as decyl (meth)acrylate and lauryl (meth)acrylate. Among these, methyl (meth)acrylate and ethyl (meth)acrylate are suitable examples of the aforementioned (meth)acrylic monomers from the viewpoint that resin particles having uniform particle diameters are easily obtained. , particularly preferably methyl (meth)acrylate.

[Constructive unit (A2) derived from polyfunctional vinyl monomer] Also, in the vinyl resin particle of the present invention, as the aforementioned structural unit (A), in addition to the structural unit (A1) derived from a monofunctional vinylic monomer, a structural unit derived from a polyfunctional vinylic monomer ( A2). By including the structural unit (A2) derived from a multifunctional vinyl monomer, the solvent resistance of the obtained vinyl resin particles can be improved, and the swelling of the vinyl resin particles can be suppressed from causing the coating composition (polyamide) to be described later. The viscosity of imide paint) is reduced, and it becomes easy to obtain vinyl resin particles with high compressive strength and uniform particle size. Examples of the structural unit (A2) include a structural unit (a3) derived from a polyfunctional (meth)acrylic monomer or a structural unit (a4) derived from a polyfunctional (poly)vinyl monomer.

上述式中，R _a21、R _a22、R _a23分別獨立表示氫原子或甲基。 Among the aforementioned structural units (A2), the structural unit (a3) derived from a polyfunctional (meth)acryl-based monomer is not limited, but examples include those having a partial structure represented by the following formula.

In the above formula, R _a21 , R _a22 , and R _a23 each independently represent a hydrogen atom or a methyl group.

Specific examples of the polyfunctional (meth)acryl-based monomer constituting the aforementioned structural unit (a3) include ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, 1 ,3-Butanediol Di(meth)acrylate, 1,4-Butanediol Di(meth)acrylate, 1,6-Hexanediol Di(meth)acrylate, Modified with Ethylene Oxide 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, propylene oxide modified neopentyl glycol di(meth)acrylate, tripropylene glycol Di(meth)acrylates of polyalcohols with 1 to 10 carbon atoms such as di(meth)acrylates; polyethylene glycol bis(methyl) with 2 to 50 added moles of ethylene oxide ) acrylate, propylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, etc., with 2-50 added moles of propylene glycol di(meth)acrylate, etc., of oxyalkylene groups with 2-4 carbon atoms Alkyl di(meth)acrylates with added moles of 2-50; ethoxylated glycerol tri(meth)acrylates, propylene oxide modified glycerol (Glycerol) tri(meth)acrylic acid Ester, ethylene oxide modified trimethylolpropane tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol monohydroxy tri(meth)acrylate, trimethylolpropane Tri(meth)acrylates of polyhydric alcohols with 1 to 10 carbon atoms such as triethoxytri(meth)acrylate; pentaerythritol tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate, Tetra(meth)acrylates of polyhydric alcohols with 1 to 10 carbon atoms such as ditrimethylolpropane tetra(meth)acrylate; pentaerythritol penta(meth)acrylate, dipentaerythritol (monohydroxyl) penta( Penta(meth)acrylate of polyhydric alcohols with 1 to 10 carbon atoms such as meth)acrylate; hexa(meth)acrylate of polyhydric alcohols with 1 to 10 carbon atoms such as pentaerythritol hexa(meth)acrylate Acrylic ester etc. are not limited to these.

Also, as specific examples of the polyfunctional (poly)vinyl monomers constituting the aforementioned structural unit (a4), polyfunctional aliphatic vinyl monomers such as isoprene and butadiene; Polyfunctional alicyclic vinyl monomers such as alkene and cyclohexadiene; polyfunctional aromatic vinyl monomers such as divinylbenzene, divinyltoluene and divinylnaphthalene; divinyl adipate, Divinyl maleate, divinyl phthalate, divinyl isophthalate and other polyfunctional vinyl ester monomers; diallyl maleate, diallyl phthalate, isophthalate Polyfunctional allyl ester monomers such as diallyl phthalate and diallyl adipate; divinyl ether, diethylene glycol divinyl ether, triethylene glycol divinyl ether, etc. Multifunctional vinyl ether monomers; multifunctional allyl ether monomers such as diallyl ether, diallyloxyethane, triallyloxyethane, etc.; divinyl ketone, Multifunctional vinyl ketone monomers such as diallyl ketone; diallylamine, diallyl isocyanurate, diallyl cyanurate, methylenebis(meth)propylene Multifunctional nitrogen-containing vinyl monomers such as amide and bismaleimide; multifunctional silicon-containing monomers such as dimethyldivinylsilane, divinylmethylphenylsilane, and diphenyldivinylsilane Vinyl monomers and the like, but are not limited thereto.

Among these, ethylene glycol di(meth)acrylate, 1, 3-Butanediol di(meth)acrylate, 1,4-Butanediol di(meth)acrylate, Trimethylolpropane tri(meth)acrylate, divinylbenzene, divinyltoluene Wait. Furthermore, from the viewpoint of easily obtaining resin particles with excellent polymerization stability and few aggregates, ethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, 1, 3-Butanediol di(meth)acrylate, among them, ethylene glycol di(meth)acrylate is preferable.

It is preferable that the structural unit (A2) derived from the said polyfunctional vinylic monomer is 1 mass % - 10 mass % with respect to the total mass of the said structural unit (A).

＜Constructive units derived from other polymerizable monomers＞ The polymer of the vinyl resin particles of the present invention may contain structural units derived from the above-mentioned (A1) [(a1), (a2)] and (A2) [(a3), ( a4)] other than the structural units of vinyl monomers (polymerizable monomers). That is, the vinyl resin particle of this invention can be a copolymer containing the monomer component (mixture) of another polymerizable monomer.

For example, examples of other polymerizable monomers other than the aforementioned monofunctional styrene-based monomers and the aforementioned monofunctional (meth)acryl-based monomers include monofunctional (meth)acrylonitrile, etc. Acrylonitrile-based monomers; monofunctional heterocycles such as N-vinylimidazole and N-vinyl-2-pyrrolidone contain vinyl monomers; vinyl acetate (vinyl acetate), isopropenyl acetate, vinyl Monofunctional vinyl ester monomers such as propionate and vinyl caprate; ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, cyclohexyl vinyl ether, ethylene glycol vinyl ether Monofunctional vinyl ether monomers such as vinyl cyclopentane, vinyl cyclohexane, ethyl vinyl benzene, etc. Monofunctional vinyl compound monomers; (meth)acrylic acid, itaconic acid, etc. Monofunctional (meth)acrylamide monomers; monofunctional (meth)acrylamide monomers such as (meth)acrylamide, N,N-dimethyl(meth)acrylamide, etc., But not limited to these.

<Reactive emulsifiers and structural units (B) derived from reactive emulsifiers> The aforementioned reactive emulsifiers are not particularly limited if they are reactive emulsifiers with the above-mentioned monomers or their polymers, but include radically polymerizable double bonds, hydrophilic Functional groups and hydrophobic groups, and the same as general emulsifiers, have emulsifying, dispersing and wetting functions.

Examples of the structure of the radically polymerizable double bond in the molecular structure include 1-propenyl, 2-methyl-1-propenyl, allyl, methallyl, vinyl, Acryl, Methacryl, etc.

As the hydrophilic functional group in the molecular structure, for example, anionic groups (-OSO ₃ ^- , -NO ₃ ^- , -OPO ₃ ^- , -B( OH) ₄ ^- , -COO ^- , etc.); cationic groups such as amine groups (-NH ₃ ⁺ , etc.); polyoxyalkylene chains such as polyoxyethylene, polyoxymethylene, polyoxypropylene, etc.; hydroxyl groups, etc.

Examples of the hydrophobic group in the molecular structure include an alkyl group, an alkenyl group, a phenyl group, an alkylphenyl group, a styrenated phenyl group, and a naphthyl group.

Reactive emulsifiers are classified into anionic emulsifiers, nonionic emulsifiers, cationic emulsifiers, amphoteric emulsifiers, etc. by the type of hydrophilic functional group included in the molecular structure. In addition, the radically polymerizable double bond, hydrophilic functional group, and hydrophobic group in the molecular structure of the reactive emulsifier may each have plural types of structures and functional groups.

Among the above, the reactive emulsifier preferably has polyoxyalkylene chains and sulfuric acid groups as hydrophilic functional groups at least inside the molecular structure.

As such a reactive emulsifier, it is not particularly limited as a general commercially available trade name, but examples thereof include ADEKA REASOAP SR, ER, SE, NE, PP (ADEKA Co., Ltd.), AQUALON HS, BC , KH (Daiichi Kogyo Pharmaceutical Co., Ltd.), LATEMUL PD (Kao Co., Ltd.), ELEMINOL JS, RS (Sanyo Chemical Industry Co., Ltd.), Antox MS (Nippon Emulsifier Co., Ltd.), etc.

上述一般式(I)中，m表示1～3之整數，從乳化性的觀點來看，較佳為表示2。 [Structural unit (b1) derived from the compound represented by general formula (I)] As described above, the polymer of the vinyl resin particle of the present invention may have the following structural unit (b1) derived from the compound represented by general formula (I) ). The compound represented by the following general formula (I) has a hydrophobic group and a hydrophilic group in the molecule, and has a copolymerizable unsaturated group. Therefore, the compound represented by the following general formula (I) can also be used as a reactive (copolymerizable) emulsifier (equivalent to the above-mentioned reactive emulsifier), and it can be expected to suppress and improve many problems in the conventional emulsion polymerization. Problems include, for example, polymerization instability and system foaming during emulsion polymerization, and deterioration of physical properties of the polymer obtained after polymerization.

In the general formula (I), m represents an integer of 1 to 3, and preferably represents 2 from the viewpoint of emulsifying properties.

AO represents an ethyleneoxy group having 2 to 4 carbon atoms. Examples of the ethyleneoxy group having 2 to 4 carbon atoms include ethyleneoxy, propyleneoxy, and butyleneoxy. Among these, as AO, an ethyleneoxy group is preferable. Ethylene oxide can form a resin emulsion with higher hydrophilicity than other ethylene oxides and a high-density hydration layer, which can further improve the stability of resin particles in aqueous dispersion media. n represents the repeating number of the alkyleneoxy unit (that is, the addition mole number of ethyleneoxy groups). n is an integer of 0 to 100, and is preferably an integer of 5 to 50, more preferably an integer of 5 to 30, from the viewpoint of the stability of resin particles in an aqueous dispersion medium.

X represents a hydrogen atom, or represents a member selected from the group consisting of -SO ₃ M, -COOM and -PO ₃ M (wherein, M represents an alkali metal atom, an alkaline earth metal atom, an ammonium group or an organic ammonium group). Anionic hydrophilic group. As an alkali metal atom, a sodium atom, a potassium atom, etc. are mentioned. Examples of the alkaline earth metal atoms include calcium atoms, barium atoms, and the like. In consideration of emulsifying properties, X is preferably a hydrogen atom, -SO ₃ NH ₄ , -SO ₃ Na or -SO ₃ K, more preferably -SO ₃ NH ₄ .

R represents a polymerizable unsaturated group, specifically, a group represented by the following formula (i) or formula (ii), wherein R ₁ represents a hydrogen atom or a methyl group.

上述式中，m、R ₁、AO、n、X係如前述之定義。

上述式中，m、R ₁、AO、n、X係如前述之定義。 Examples of the structural unit (b1) derived from the compound represented by the general formula (I) above include the following structures.

In the above formula, m, R ₁ , AO, n, and X are as defined above.

In the above formula, m, R ₁ , AO, n, and X are as defined above.

上述式中，m、AO、n、X係如前述之定義。 Preferable examples of the compound represented by the aforementioned general formula (I) include compounds represented by the following formula (I-1).

In the above formula, m, AO, n, and X are as defined above.

上述式中，m、AO、n、X係如前述之定義。 In addition, examples of the structural unit (b1) derived from the compound represented by the above formula (I-1) include the following structures.

In the above formula, m, AO, n, and X are as defined above.

The compound represented by the above-mentioned general formula (I) can be a commercially available product, for example, AQUALON AR series (AR-10, AR-1025, AR-20, AR-2020) manufactured by Daiichi Kogyo Chemical Co., Ltd., etc. are mentioned.

In the vinyl resin particle (polymer) of the present invention, from the standpoint of copolymerizability during polymerization, etc., when the total structural units of the polymer are defined as 100% by mass, for example, the ratio of the structural unit (A) can be determined 98.0% by mass to 99.9% by mass, and the proportion of the structural unit (B) (for example, structural unit (b1)) can be set to 0.1% by mass to 2.0% by mass. Also, when the total structural unit of the vinyl resin particle (polymer) is 100% by mass, the ratio of the aforementioned structural unit (A1) may be 88 to 99% by mass, and the ratio of the aforementioned structural unit (A2) may be 0.9 to 10% by mass, and the ratio of the aforementioned structural unit (B) can be set to 0.1 to 2% by mass. Furthermore, the ratio of the aforementioned structural unit (B) can be read as the ratio of the structural unit (b1), and can also be read as the ratio of the structural unit (b1) to the total of structural units (B) other than the structural unit (b1).

In addition, the particle size is uniform, and from the viewpoint of obtaining stable resin particles with respect to the solvent, for example, the ratio of the structural unit (a1) derived from the monofunctional styrene-based monomer in the structural unit (A) It can be set at 10% by mass to 99% by mass, and the proportion of the structural unit (a2) derived from monofunctional (meth)acryl-based monomers can be set at 0% by mass to 80% by mass, derived from polyfunctional vinyl-based monomers The proportion of the structural unit (A2) of the monomer can be set at 1% by mass to 10% by mass, and the proportion of the structural unit derived from other polymerizable monomers can be set at 0% by mass to 5% by mass (the total of the above is 100% by mass ).

[Manufacturing method of vinyl resin particles] The vinyl resin particles of the present invention can be obtained by emulsification polymerization of monomer components comprising the above vinyl monomers and reactive emulsifiers (such as compounds represented by general formula (I)). The emulsion polymerization method is preferable in that particles having a small particle size can be easily obtained. Furthermore, as the above-mentioned vinyl monomers, various monomers listed in the foregoing description [monofunctional vinyl monomers (monofunctional styrene monomers, monofunctional (meth)acryl monomers) , polyfunctional vinyl monomers (polyfunctional (meth)acrylic monomers, polyfunctional (poly)vinyl monomers), other polymerizable monomers] as reactive emulsifiers, respectively exemplifying the aforementioned compounds, etc. . A preferred aspect of emulsion polymerization includes: adding the polymerization mixed liquid containing the aforementioned monomer components, polymerization initiator, and other additives (surfactant, protective colloid agent, chain transfer agent, pH adjuster, etc.) as desired In the emulsion polymerization step of the emulsion polymerization, it may be desired to include an aging step of aging the reaction liquid obtained in the emulsion polymerization step.

The aforementioned emulsion polymerization is usually carried out in an aqueous dispersion medium, and the aqueous dispersion medium is not particularly limited, and examples thereof include water, a mixed solution of water and an alcoholic solvent, and the like. From the viewpoint of stability (non-agglomeration) of vinyl resin particles formed after emulsion polymerization, water is preferred as the aqueous dispersion medium. The usage-amount of an aqueous dispersion medium can be suitably set so that the content of the vinyl resin particle which exists in a system after emulsion polymerization becomes a desired ratio. For example, the content of vinyl resin particles in the system is set at 1% to 70% by mass, 10% to 60% by mass, 20% to 50% by mass, etc., and the amount of the aqueous dispersion medium used can be appropriately set. .

The polymerization initiator used in the aforementioned emulsion polymerization is not particularly limited, and known polymerization initiators can be used. For example, azobisisobutyronitrile, 2,2-azobis(2-methylbutyronitrile), 2,2-azobis(2,4-dimethylvaleronitrile), 2,2- Azobis(2-diaminopropane) hydrochloride (Hydrochloride), 4,4-azobis(4-cyanovaleric acid), 2,2-azobis(2-methylpropionamidine (Propion Amidine)), azo compounds such as 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropionamidine] 4 hydrate; persulfuric acid such as potassium persulfate and ammonium persulfate Salt; peroxides such as hydrogen peroxide, benzoyl peroxide, p-chlorobenzoyl peroxide, lauryl peroxide, ammonium peroxide, etc., but are not limited to these examples. Among them, an azo compound or a peroxide can also be used as a decomposition accelerator, that is, when vinyl resin particles are used as a porous material, they can be preferably used because they have a function of accelerating thermal decomposition. Although the amount of the polymerization initiator used is not particularly limited, from the viewpoint of increasing the polymerization rate and reducing the residual amount of unreacted monomers, it is preferably 0.05 parts by mass or more per 100 parts by mass of monomer components It is 0.1 mass part or more, and can be made into 5 mass parts or less from a viewpoint of polymerization stability, for example.

In the present invention, the above-mentioned reactive emulsifier, and the compound represented by the above-mentioned general formula (I) can also function as an emulsifier, although it can start and complete the emulsion polymerization well, but within the scope of not impairing the effect of the present invention , can further use the surfactant (emulsifier) generally used in emulsion polymerization as other additives. As said surfactant, an anionic surfactant, a cationic surfactant, or/and other nonionic surfactants can be used together. For example, examples of anionic surfactants (anionic emulsifiers) include fatty acid soaps; abietic acid soaps; alkyl sulfates such as ammonium lauryl sulfate and sodium lauryl sulfate; dodecylsulfonic acid Alkyl sulfonates of ammonium, sodium dodecylsulfonate, etc.; alkylarylsulfonates of ammonium dodecylbenzenesulfonate, sodium dodecylbenzenesulfonate, sodium dodecylnaphthalenesulfonate, etc. acid salt; polyoxyalkylene alkyl sulfate; polyoxyalkylene aryl sulfate; polyoxyalkylene alkyl aryl sulfate; dialkyl sulfosuccinate; arylsulfonic acid-formalin condensate; Fatty acid salts such as ammonium laurate, sodium stearate, etc. As a cationic surfactant, stearyl trimethyl ammonium, cetyl trimethyl ammonium, lauryl trimethyl ammonium, etc. are mentioned. Examples of nonionic surfactants include polyoxyalkylene alkylphenyl ethers, polyoxyalkylene alkyl ethers, alkyl polyglucosides, polyglyceryl alkyl ethers, polyoxyalkylene fatty acid esters, polyglyceryl fatty acid esters, Sorbitan fatty acid esters, etc. In the emulsification polymerization step, when a surfactant is used, the usage amount thereof may be, for example, 0.05 parts by mass or more, or 0.1 parts by mass or more, or 0.3 parts by mass or more, relative to 100 parts by mass of the monomer component. The upper limit can be set to, for example, 10 parts by mass, 8 parts by mass or less, and 5 parts by mass or less.

In addition, for the purpose of improving polymerization stability during emulsion polymerization, known protective colloid agents may be used together as other additives. Examples of the protective colloid agent include fully saponified polyvinyl alcohol, partially saponified polyvinyl alcohol, hydroxyethyl cellulose, carboxymethyl cellulose, methyl cellulose, polyacrylic acid, gum arabic, and the like.

In addition, as other additives, a known chain transfer agent or a pH adjuster may be used in combination. Examples of the chain transfer agent include octyl mercaptan, dodecyl mercaptan, mercaptoethanol, thioglycolic acid, allyl alcohol, isopropyl alcohol, and sodium hypophosphite. Examples of the aforementioned pH adjuster include inorganic acids such as hydrochloric acid, sulfuric acid, and phosphoric acid; organic acids such as citric acid, succinic acid, malic acid, and lactic acid; and inorganic bases such as sodium hydroxide, potassium hydroxide, sodium carbonate, and potassium carbonate. ; Alkanolamines such as monoethanolamine, diethanolamine, triethanolamine, isopropanol, etc., aliphatic amines such as ethylenediamine, propylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, etc. Aromatic polyamines such as phenylenediamine and methylenediamine, organic bases such as heterocyclic polyamines such as piperazine and aminoethylpiperone, etc.

In the monomer component attached to the aforementioned emulsion polymerization, the usage amount (incorporation ratio) of each monomer can be appropriately set. For example, relative to the total amount of all monomers (total 100 mass%), the proportion of vinyl monomers can be set at 98.0 mass% to 99.9 mass%, and the proportion of reactive emulsifiers (such as compounds represented by general formula (I)) It can be set to 0.1 mass % - 2.0 mass %. Also, for example, with respect to the total amount of all monomers (total 100% by mass), the ratio of the monofunctional vinyl monomer may be 88% by mass to 99% by mass, and the ratio of the polyfunctional vinyl monomer may be 0.9% by mass. % to 10% by mass, and the proportion of the aforementioned reactive emulsifier can be set at 0.1 to 2% by mass. Furthermore, among the vinyl monomers (total 100% by mass), the monofunctional styrene-based monomer can be set to 10% by mass to 99% by mass, and the monofunctional (meth)acryl-based monomer can be set to 0% by mass. % by mass to 80% by mass, the polyfunctional vinylic monomer can be set to 1% by mass to 10% by mass, and other polymerizable monomers can be set to 0% by mass to 5% by mass.

The aforementioned emulsion polymerization may be carried out by a known emulsion polymerization method, for example, a monomer dropping method, a pre-emulsion method, a one-shot polymerization method, etc. may be used. From the viewpoint of industrial productivity, it is preferable to employ the pre-emulsion method from the viewpoint of stably polymerizing and obtaining a polymer (resin particle) with few aggregates.

For the aforementioned emulsion polymerization, the aforementioned monomer components, polymerization initiators, and methods of introducing other additives are not particularly limited, and can be set appropriately. For example, in the pre-emulsion method, the sequence of emulsification polymerization is to emulsify the vinyl monomer in an aqueous dispersion medium such as a reactive emulsifier (such as a compound represented by general formula (I), etc.) and water in advance to obtain a pre-emulsion . Furthermore, it can be implemented by dropping the obtained pre-emulsion into a reaction container, adding a polymerization initiator appropriately, and carrying out emulsion polymerization. In addition, an operation such as dropping the remaining polymerization mixed liquid after starting the emulsion polymerization using a part of the above-mentioned mixed liquid for polymerization may be performed. Alternatively, it is also possible to use a mixed liquid consisting of a part of the total amount of the aforementioned monomer components and a part of the polymerization initiator (and other additives) in advance, and after the emulsion polymerization is started, the remaining aforementioned monomer components and polymerization The operation of starting agent (and other additives) separately or mixed and dropped.

Also, by repeating the emulsion polymerization step for two or more steps, that is, for example, in a configuration including the first emulsion polymerization step and the second emulsion polymerization step, the core can be formed in the first emulsion polymerization step, and then, by In the second emulsion polymerization step, a shell portion is formed on the surface of the core to form core-shell resin particles. In this case, the second emulsion polymerization step can be carried out multiple times. When the second emulsion polymerization step is carried out, a brand new The resin particles of the shell part. When the first emulsion polymerization step and the second emulsion polymerization step are included, the composition of the monomer components used in the individual steps can be changed, and the monomer components used in the individual steps can be set to one type of monomer. That is, in the first emulsion polymerization step and the second emulsion polymerization step, different monomers (one type) can be used, a mixture of monomers and a monomer (one type), or different monomers can be used. Mixtures are used in individual steps. When using a mixture of the same monomers, a mixture in which the mixing ratio of the monomers is changed can be used. For example, in the first emulsion polymerization step, monofunctional styrene-based monomers, polyfunctional vinyl monomers, and reactive emulsifiers (such as those represented by general formula (I)) can be used to contain monofunctional vinyl monomers. compound), and then, in the second emulsion polymerization step, monofunctional styrene-based monomers and monofunctional (meth)acryl-based monomers, and polyfunctional vinyl monomers containing monofunctional vinyl monomers can be used. It is a mixture of monomers and reactive emulsifiers (such as compounds represented by general formula (I)).

The polymerization temperature in the above-mentioned emulsion polymerization may be appropriately set according to the polymerization initiator used, etc., but may be, for example, 30°C to 90°C or 50°C to 80°C. The polymerization time can be appropriately set in accordance with the reaction rate obtained from the amount of monomer components introduced and the remaining amount in the reaction solution, but it is usually about 1 hour to 12 hours, for example, about 2 hours to 8 hours.

Next, the aging step is performed for the purpose of reducing unreacted monomers or stabilizing the dispersion of polymer particles (vinyl resin particles) obtained by emulsion polymerization after the aforementioned emulsion polymerization step. The aging temperature in the aforementioned aging step can be set, for example, at 50°C to 90°C, or, for example, at 70°C to 85°C. It is expected that the amount of unreacted monomer mixture can be reduced while suppressing the aggregation of particles by setting the aging temperature within the aforementioned range. Although the aging time can be appropriately set in response to the reaction rate obtained from the total amount of the monomer components introduced and the residual amount of the monomer components in the reaction solution, it is usually 1 hour to 12 hours, preferably 2 hours. Hours to about 8 hours.

In the aforementioned aging step, a surfactant may be added if necessary for the purpose of making it easier to suppress aggregation of polymer particles during aging. As the surfactant used in the aforementioned aging step, it is preferable to use the surfactants listed in the aforementioned emulsion polymerization step, and an anionic surfactant or a nonionic surfactant can also be used. As the amount of the surfactant used in the aging step, relative to the total amount of monomer components attached to the emulsion polymerization step: 100 parts by mass, for example, 0.05 parts by mass or more, can be set to 0.1 parts by mass or more, 0.3 parts by mass More than one part, and, for example, not more than 10 parts by mass, may be not more than 8 parts by mass, or not more than 5 parts by mass.

After the aforementioned emulsification polymerization step (and optional aging step), the formed polymer is in the form of a dispersion contained in an aqueous dispersion medium (also called a dispersion liquid), and the vinyl resin particles of the present invention can be obtained . The content of the vinyl resin particles (polymer) in the aqueous dispersion medium is not particularly limited, but may be, for example, 10 to 80% by mass, 20 to 70% by mass, or 30 to 60% by mass.

Furthermore, the present invention is also aimed at a method for producing an aqueous dispersion of vinyl resin particles, which includes emulsification polymerization of a monofunctional vinyl monomer and a multifunctional vinyl monomer in the presence of a polymerization initiator in an aqueous dispersion medium. The step of reactive emulsifier of the vinyl monomer of the vinyl monomer, and, for example, the compound represented by the aforementioned general formula (I) different from the aforementioned vinyl monomer.

[Particle diameter of vinyl resin particles] The vinyl resin particles of the present invention are preferably particles having a median diameter D ₅₀ of 0.05 μm to 2.0 μm. In addition, as the partial diameter in the present invention, the value of the 50% volume diameter based on the volume measured by the dynamic light scattering method can be used. Generally speaking, when the particle diameter is reduced, the aggregation of the particles is likely to be caused especially during polymerization, but since the vinyl resin particles of the present invention have an excellent aggregation inhibitory effect in its dispersion, the particles of the vinyl resin particles can be The diameter is defined as a relatively small range. By setting the median diameter within the above range, fine pores can be formed in the resin when used as a porous material of thermosetting resin. However, when the above-mentioned median diameter is less than 0.2 μm, the particle diameter may be too small to contribute to the formation of sufficient pores. Moreover, when it exceeds 1.5 micrometers, there exists a possibility that the mechanical strength of the thermosetting resin which becomes a cavity object may fall.

[Thermal decomposition temperature of vinyl resin particles] The vinyl resin particles of the present invention preferably have a thermal decomposition temperature lower than that of a thermosetting resin described later under atmospheric pressure. In this specification, the so-called thermal decomposition temperature refers to the weight loss accompanying the thermal decomposition of the sample when measured in a thermogravimetric analysis device (TGA: Thermo Gravimetry Analyzer) under the conditions of JISK7120 (thermogravimetric measurement method for plastics) the starting temperature. Although it also depends on the type of thermosetting resin to be used, the thermal decomposition temperature of the vinyl resin particles of the present invention in a nitrogen atmosphere is, for example, 340-440°C, preferably 370-410°C.

[Vinyl resin particles and their dispersions] The aforementioned vinyl resin particles can be obtained in the form of a dispersion (dispersion liquid) dispersed in an aqueous dispersion medium through the aforementioned emulsion polymerization step, and can be used as dispersions in various solvents according to the application of the resin particles. For example, in the above-mentioned dispersion in the aqueous dispersion medium, a solvent can be used instead of the aqueous dispersion medium as a dispersion dispersed in an organic solvent (organic solvent dispersion). Also, the vinyl resin particles (powder) obtained by removing the aqueous dispersion medium or the organic solvent from the dispersion dispersed in the aforementioned aqueous dispersion medium or organic solvent can be used. Examples of methods for removing the aforementioned aqueous dispersion medium or organic solvent include freeze-drying, hot-air drying, and spray-drying. Furthermore, the obtained resin particles (powder) can be dispersed again in an aqueous dispersion medium or an organic solvent, and used as an aqueous dispersion or an organic dispersion.

Examples of the aforementioned organic solvents include lower alcohols such as methanol, ethanol, and isopropanol; N,N-dimethylformamide (DMF) and N,N-dimethylacetamide (DMAc); Linear amides; N-methyl-2-pyrrolidone (NMP) and other cyclic amides; γ-butyrolactone (GBL) and other ethers; ethyl cellosolve, ethylene glycol, etc. Alcohols, acetonitrile, etc. This substitution can be performed by common methods such as distillation and ultrafiltration. At this time, the content of the vinyl resin particles in the organic solvent dispersion can be appropriately set according to its use. For example, with respect to the total mass of the organic solvent dispersion, the content of the resin particles can be set at 1% by mass to 70% by mass, 10% by mass to 60% by mass, and 20% by mass to 50% by mass. In the organic solvent dispersion, if the ratio of the resin particles is less than 1% by mass, it is not economical, and if it is more than 70% by mass, it will not become a stable dispersion and may cause aggregation or sedimentation of the resin particles. There is a possibility that handling may deteriorate when mixed with a thermosetting resin described later. In addition, the viscosity of the organic solvent dispersion can be set at about 0.6 mPa·s to 100 mPa·s, for example, at 20°C. The aforementioned dispersion may further contain other compounds such as a surfactant.

[thermosetting resin] The vinyl resin particles of the present invention are suitable for making porous thermosetting resins. That is, according to the present invention, a porous material composed of the aforementioned vinyl resin particles can be provided. As a thermosetting resin, a polyimide resin, a diallyl phthalate resin, etc. are mentioned, for example. Among these, polyimide resin is mentioned as a suitable example as a thermosetting resin which becomes the target of making the vinyl resin particle of this invention porous. By using the vinyl resin particle of the present invention as a porous material of polyimide resin, uniform pores can be formed in the film of polyimide resin.

[Method for Porousizing Thermosetting Resin (Method for Manufacturing Porous Material)] The method for making the thermosetting resin porous (the method for producing a porous body) using the vinyl resin particles of the present invention is not particularly limited. For example, when a polyimide resin is used as a thermosetting resin, first, a coating composition comprising polyimide precursor polyamic acid, vinyl resin particles of the present invention, and a solvent is coated on a substrate above, forming a coating film (coating film forming step), drying the coating film, that is, removing the solvent from the coating film, and forming a coating film (polyimide porous membrane (precursor membrane) (precursor membrane forming step). Next, the film (precursor film of the polyimide porous membrane) can be fired to convert the polyimide precursor into polyimide, and remove (thermally decompose) the vinyl resin particles (removal of the vinyl resin particles The removal step) to obtain a porous membrane of polyimide. The removal step (calcination step) of removing the aforementioned vinyl resin particles can be carried out at a temperature at which the polyimide precursor can be converted into polyimide, and the vinyl resin particles can be decomposed and disappeared. Also, before removing the vinyl resin particles, the film (precursor film of the polyimide porous membrane) can be peeled off from the substrate (peeling step), and this unfired film can be fired (removal of the vinyl resin particles). particle removal step). Hereinafter, although a specific example will be described about the method of making the thermosetting resin porous, it is not limited to the following method.

<Coating film formation process> This step is the step of coating the polyamide acid containing the polyimide precursor, the vinyl resin particles of the present invention, and the coating composition of the solvent on the substrate to form a coating film. As said base material, PET film, a SUS board|substrate, a glass board|substrate etc. are mentioned, for example.

"Coating composition" As the aforementioned polyamic acid, a product obtained by polymerizing arbitrary tetracarboxylic dianhydrides and diamines can be used without particular limitation. The above-mentioned tetracarboxylic dianhydride and diamine can be appropriately selected from compounds conventionally used as synthesis raw materials of polyamic acid. The above-mentioned tetracarboxylic dianhydride may be an aromatic tetracarboxylic dianhydride or an aliphatic tetracarboxylic dianhydride, and the above-mentioned diamine may be an aromatic diamine or an aliphatic diamine. The means for producing the polyamic acid is not particularly limited, and for example, known methods such as a method of reacting a tetracarboxylic dianhydride component and a diamine component in a solvent can be used. At this time, the usage amount (incorporation amount) of tetracarboxylic dianhydride and diamine is not particularly limited, but the diamine can be set at 0.50 mol or more to 1.50 mol relative to 1 mol of tetracarboxylic dianhydride, for example. ratio below the ear. Also, when the synthesis of polyamic acid is carried out in a solvent described later, the reaction solution of polyamic acid can be directly used as a polyamic acid-containing liquid for preparation of a paint composition.

As the solvent used in the aforementioned coating composition, water or organic solvent or a combination thereof may be mentioned. Furthermore, the organic solvent used in the paint composition is preferably a neutral or weakly alkaline compound in water from the viewpoint of avoiding hydrolysis of polyamic acid. As a suitable example of an organic solvent, various organic solvents mentioned in the organic solvent dispersion of the said resin particle are mentioned, for example.

Furthermore, a dispersant may be further added to the aforementioned coating composition for the purpose of uniformly dispersing the vinyl resin particles. When a dispersant is used, it can be used at, for example, 0.01 mass % or more and 5 mass % or less with respect to the above-mentioned fine particles.

The above-mentioned coating composition can be produced by mixing the above-mentioned various components respectively in specified amounts, and the specific order is not particularly limited. When the above-mentioned coating composition is used as a polyamic acid-microparticle composite film (precursor film) described later, for example, vinyl resin particles may be contained in such a manner that the ratio of vinyl resin particles/polyamic acid becomes 0.5 to 4.0 (mass ratio). and polyamide. Alternatively, in the case of the aforementioned composite film, these components may be contained such that the volume ratio of vinyl resin particles/polyamic acid becomes, for example, 1.0 to 5.0. The solid content concentration of the paint composition is not particularly limited, but it is, for example, 1% by mass or more, 5% by mass or more, and may be 10% by mass or more, and the upper limit thereof is, for example, 60% by mass or less, for example, 30% by mass or less. In addition, the so-called solid content concentration here means the concentration of components other than the solvent, which may be a liquid component, and is included in the weight as a solid content. The viscosity of the coating composition is not particularly limited as long as it can form a coating film with a desired film thickness. For example, the viscosity of the paint composition can be set at 300 cP or more and 20,000 cP or less.

＜Precursor film formation process＞ This step is a step of removing the solvent from the coated film obtained in the previous step to form a precursor film of a polyimide porous film. In order to remove the solvent from the aforementioned coating film, apply the aforementioned coating composition on the base material to form a coating film, and then conduct the coating under normal pressure or vacuum at 0°C to 100°C, preferably at normal pressure above 10°C It can be dried below 100°C.

Furthermore, the precursor film may be formed directly on the substrate, or may be formed on an underlying film different from the aforementioned precursor film formed on the substrate. In addition, after forming a precursor film using the above-mentioned coating composition, a film can be further formed on the upper layer to form an upper layer film different from the aforementioned precursor film. Also, in this specification, an aspect in which an underlayer film is provided on a base material, or an aspect in which an upper layer film is provided on a precursor film is included in the step of forming a precursor film.

＜Peel off procedure＞ After the aforementioned <precursor film forming step>, before the <step of removing vinyl resin particles> described later, a peeling step of peeling the precursor film from the base material may be included. When this step is included, the base material does not require heat resistance to withstand the temperature at which the precursor film is fired.

<Step of removing vinyl resin particles (firing step)> In this step, when the aforementioned polyimide porous membrane is imidized by firing, the polyimide porous membrane is thermally decomposed at the same time either during the imidization or after the imidization. Invented vinyl resin particles and removal steps. Through this step, uniform and fine pores are formed in the polyimide resin film, and a polyimide porous film can be obtained. In this step, the removal of the vinyl resin particles may be performed while imidizing the polyamic acid, or may be performed after imidizing the polyamic acid.

The method for imidizing polyamide acid is not particularly limited. The imidization may be any of thermal imidization and chemical imidization. As the chemical imidization, a method of immersing a precursor film containing polyamide acid in acetic anhydride or a mixed solvent of acetic anhydride and isoquinoline or the like can be used. Among the above-mentioned imidization methods, firing for thermal imidization is preferred because removal by washing of the imidation agent is unnecessary. Hereinafter, the firing related to thermal imidization will be described.

The firing temperature varies depending on the structure of the polyamic acid, but is preferably from 120°C to 500°C, more preferably from 150°C to 450°C, and still more preferably from 300°C to 450°C. The firing conditions can also use, for example, a method in which the temperature is raised from room temperature to about 400°C to 450°C in about 3 hours, and then kept at the same temperature for about 2 to 30 minutes, or includes steps from room temperature, for example, at 50°C. The drying-thermal imidization method is a continuous or step-by-step temperature-raising operation where the temperature is raised to (each process is kept for about 20 minutes) 400°C-450°C, and finally kept at 400°C-450°C for about 2-30 minutes. When the precursor film is formed on the substrate, and the precursor film or the laminated film containing the precursor film is peeled off from the substrate once, and the firing step is carried out, the end of the precursor film or laminated film can also be fixed on the A method of preventing deformation caused by firing, such as a frame made of SUS.

The film thickness of the polyimide porous film obtained after baking can be calculated|required as an average by measuring the thickness of several points with a micrometer etc., for example. The preferred average film thickness varies depending on the application of the polyimide porous film, but when it is used in a separator, for example, it is preferably from 5 μm to 500 μm, more preferably from 10 μm to 100 μm, and even more preferably It is not less than 15 μm and not more than 30 μm. When used in a filter or the like, it is preferably from 5 μm to 500 μm, more preferably from 10 μm to 300 μm, and still more preferably from 20 μm to 150 μm.

The polyimide porous film thus obtained is colored opaque, yellow or dark brown. In addition, regardless of the film thickness, the polyimide porous film is a porous film distributed in a state in which spherical pores communicate with each other throughout the film, and the front and back sides are connected. [Example]

Hereinafter, the present invention is illustrated by examples. However, the present invention is not limited by these Examples and Comparative Examples. Also, the test method of vinyl resin particles is as follows.

<median diameter> For the dispersion liquid (resin particle aqueous dispersion) in which the resin particles are dispersed in water, the volume The standard particle size distribution is obtained as the median diameter (D50) in the particle size distribution.

＜Mix stability test＞ Dry the aqueous dispersion of resin particles with a hot air convection dryer at 105°C, measure 1g of the obtained resin particle powder and 5g of N,N-dimethylacetamide in a sample bottle, and clean them with an ultrasonic cleaner Disperse for 30 minutes. The state of the obtained resin particle dispersion (organic solvent dispersion) was visually confirmed, and the mixing stability with the organic solvent of the resin particles was evaluated on the following evaluation criteria. [Evaluation benchmark] ◯: Gelation cannot be maintained to maintain fluidity. (good) Δ: Although not gelled, fluidity was lost. (ordinary) x: The resin particles are gelled or dissolved. (bad)

＜Solvent resistance test＞ The resin particle dispersion (organic solvent dispersion) prepared in the aforementioned <mixing stability test> was air-dried at room temperature. Electron microscope observation of the dried product was carried out to confirm the shape of the particles and the presence or absence of fusion between the particles (dissolution of the particles), and the solvent resistance of the resin particles was evaluated using the following evaluation criteria. [Evaluation benchmark] ○: Particles remain true spherical, and there is no fusion between particles. (good) Δ: Either shape change of particles or fusion of particles occurs. (ordinary) ×: Both the shape change of the particles and the fusion of the particles occurred. (bad)

＜Thermal decomposition temperature＞ The resin particle aqueous dispersion was dried with a hot air convection dryer at 105°C, and 10 mg of the obtained resin particle powder was used in a differential thermal balance ThermoplusEVO2 (registered trademark) TG8121 (trade name, manufactured by Rigaku Co., Ltd.), according to JIS conditions, As a reference, heat up from 25°C to 600°C with aluminum oxide, nitrogen flow rate of 100ml/min, and temperature rise rate of 10°C/min, read the thermal decomposition initiation temperature from the obtained TG curve, and use this as the index of vinyl resin particles. thermal decomposition temperature.

[Preparation of vinyl resin particles] Example 1 383.0 g of ion-exchanged water was placed in a 1.0-liter glass container equipped with a stirrer, a thermometer, a temperature controller, a capacitor, and a dropping device, and nitrogen gas was introduced while stirring to perform nitrogen substitution. Then, it is heated with a mantle heater and controlled at a temperature of 72±2°C as a polymerization vessel. Put 122.4 g of ion-exchanged water and ammonium polyoxyethylene styrenated allyl phenyl ether sulfate as a compound (reactive emulsifier) represented by general formula (I) in a glass container with a capacity of 1.0 L inside the mixer Salt (AQUALON AR-1025 (25% aqueous solution) manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.) 12.8 g, 378.6 g of styrene (Styrene Monomer manufactured by Asahi Kasei Co., Ltd.) as a monofunctional monomer, and 378.6 g as a polyfunctional monomer 22.2 g of ethylene glycol dimethacrylate (Acryester ED manufactured by Mitsubishi Chemical Co., Ltd.) was stirred to obtain a monomer emulsion in which styrene and ethylene glycol dimethacrylate were emulsified in ion-exchanged water. Put 48.6 g of ion-exchanged water and 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropane as a polymerization initiator in a 0.1L glass container with a mixer 3.1 g of amidine] tetrahydrate (VA-057 manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was stirred and dissolved to obtain an aqueous polymerization initiator solution. In the polymerization container, 26.8 g of the prepared monomer emulsion was added, and 5.0 g of the prepared aqueous solution of the polymerization initiator was put in, and the initial polymerization was carried out for 120 minutes. After initial polymerization for 120 minutes, the remaining monomer emulsion and polymerization initiator aqueous solution were spent 240 minutes in a liquid delivery pump to send liquid to the above-mentioned polymerization container to carry out drop polymerization. After completion of the dropping, co-washing of the liquid supply line was performed with 9.0 g of ion-exchanged water. After the polymerization reaction continued for 120 minutes, it was cooled to 40° C. to obtain a cross-linked polymer aqueous dispersion (resin particle aqueous dispersion) with a solid content of 40%.

Example 2 In addition to replacing 378.6g of styrene in Example 1, and replacing 374.2g of styrene with 4.4g of methyl methacrylate and ethylene glycol dimethacrylate, trimethylolpropane trimethacrylate was used instead Other than that, polymerization was carried out in the same manner as in Example 1 to obtain a cross-linked polymer aqueous dispersion (resin particle aqueous dispersion) with a solid content of 40%.

Example 3 In addition to replacing 378.6g of styrene in Example 1, and replacing 388.8g of styrene with 22.2g of ethylene glycol dimethacrylate, a divinylbenzene mixture (DVB570, Containing 57% of divinylbenzene, containing 43% of ethylvinylbenzene) 12.0g (divinylbenzene: 6.84g, ethylvinylbenzene: 5.16g), others are carried out in the same manner as in Example 1, to carry out Polymerized to obtain a cross-linked polymer aqueous dispersion (resin particle aqueous dispersion) with a solid content of 40%.

Example 4 In addition to replacing 378.6g of styrene in Example 1, and replacing 364.7g of styrene and 4.0g of methacrylate with 22.2g of ethylene glycol dimethacrylate, use 1,3-butanediol dimethacrylate instead Except for 32.1 g of methacrylate, it carried out similarly to Example 1, and superposed|polymerized, and obtained the crosslinked polymer aqueous dispersion (resin particle aqueous dispersion) of 40% of solid content.

Comparative example 1 343.3 g of ion-exchanged water was placed in a 1.0-liter glass container equipped with a stirrer, a thermometer, a temperature controller, a capacitor, and a dripping device, and nitrogen gas was introduced while stirring to perform nitrogen substitution. After nitrogen substitution, put 0.6 g of 40% triethanolamine lauryl sulfate aqueous solution (ALSCOPE LS-40T manufactured by Toho Chemical Industry Co., Ltd.) as an emulsifier, heat with a mantle heater, and control the temperature at 72 ± 2 ° C, as aggregate container. Put 169.7g of ion-exchanged water, 3.5g of 40% triethanolamine lauryl sulfate aqueous solution as an emulsifier, 364.9g of styrene as a monofunctional monomer, and 2-hydroxyethyl 11.1 g of methyl methacrylate (Acryester HO manufactured by Mitsubishi Chemical Co., Ltd.) was stirred and dissolved to obtain a monomer emulsion in which styrene and 2-hydroxyethyl methacrylate were emulsified in ion-exchanged water. Put 49.1 g of ion-exchanged water and 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropane as a polymerization initiator in a 0.1L glass container with a mixer. 3.2 g of amidine] tetrahydrate was stirred and dissolved to obtain a polymerization initiator aqueous solution. 28.4 g of the prepared monomer emulsion and 4.5 g of the prepared aqueous solution of the polymerization initiator were added to the polymerization container, and the initial polymerization was carried out for 120 minutes. After initial polymerization for 120 minutes, the remaining monomer emulsion and polymerization initiator aqueous solution were spent 300 minutes in a liquid-feeding pump, respectively, to feed the liquid into the above-mentioned polymerization vessel to carry out dropwise polymerization. After the polymerization reaction continued for 120 minutes, it was cooled to 40° C. to obtain a non-crosslinked polymer aqueous dispersion (resin particle aqueous dispersion) with a solid content of 40%.

Comparative example 2 In addition to replacing 12.8 g of polyoxyethylene styrenated propenyl phenyl ether sulfate ammonium salt (25% aqueous solution) in Example 1, 8.0 g of triethanolamine lauryl sulfate (40% aqueous solution) was used instead, and the styrene was changed to Be 392.8g, ethylene glycol dimethacrylate change into 8.0g, other carry out similarly with embodiment 1, carry out polymerization, and obtain the cross-linked polymer aqueous dispersion (resin particle aqueous dispersion) of 40% solid content body).

For the aqueous dispersions of resin particles obtained in Examples 1-4 and Comparative Examples 1-2, the median diameter of the resin particles, the mixing stability of the resin particles and the organic solvent, Solvent resistance of resin particles, and thermal decomposition temperature of resin particles. Table 1 shows the obtained results. Also, the electron micrographs obtained from the <Solvent Resistance Test> are shown in Figure 1 ((a): Example 1, (b): Example 2, (c): Example 3, (d): Implementation Example 4) and FIG. 2 ((a): Comparative Example 1, (b): Comparative Example 2).

[Test Example] Production of Porous Membrane A porous membrane was prepared using the crosslinked polymer aqueous dispersion (resin particle aqueous dispersion) obtained in Examples 1-4 and Comparative Examples 1-2.

<Example 5: Production of Porous Polyimide Membrane (1)> ＜Preparation of paint composition＞ The crosslinked polymer aqueous dispersion (resin particle dispersion) of Example 1 was spray-dried using a spray dryer ADL-311S-A (manufactured by Daiwa Science Co., Ltd.), to obtain powder vinyl resin particles. Stir and mix 10.7 parts by mass of vinyl resin particles and 43.0 parts by mass of N,N-dimethylacetamide (DMAc) in the resulting powder to make a DMAc dispersion, and add polyamic acid (PMDA: Pyroquinone dianhydride and ODA: 46.3 parts by mass of N,N-dimethylacetamide 20 mass % solution of polyamic acid produced by 4,4-diaminodiphenyl ether) in three Disperse with a roller mill to obtain a coating composition with a uniform composition.

＜Manufacture of polyimide porous membrane＞ The above coating composition was coated on a polyethylene terephthalate film, and dried at 90° C. for 5 minutes to obtain a precursor film of a polyimide porous film. After the obtained precursor film is peeled off from the polyethylene terephthalate film, the precursor film is fired at 420°C for 5 minutes in a firing furnace, and polyamide acid is decomposed while thermally decomposing the vinyl resin particles. imidization to obtain the polyimide porous membrane of Example 5.

<Examples 6-8, Comparative Examples 3-4: Production of Porous Polyimide Membrane (2)> As the cross-linked polymer aqueous dispersion (resin particle aqueous dispersion), in addition to replacing the aqueous dispersion of Example 1, each of the cross-linked polymers of Examples 2 to 4 or Comparative Examples 1 to 2 shown in Table 2 was used instead. Except for the polymer aqueous dispersion, the other procedures were the same as in Example 5, and the powdered vinyl resin particles were prepared, and the coating composition was prepared from the powder particles, and from the coating composition, Example 6 was obtained. ~8 or the polyimide porous membrane of Comparative Examples 3-4.

＜Evaluation of Porous Membrane＞ The following evaluations were performed on the polyimide porous membranes of Examples 5 to 8 and Comparative Examples 3 to 4. The obtained results are shown in Table 2. [Stress and elongation at break] Each porous film was cut out to a size of 3 cm×3 mm to obtain strip-shaped samples. The stress (MPa; tensile strength) and elongation at break (%GL) of this sample at break were evaluated using EZ Test (manufactured by Shimadzu Corporation). [breathability] Each porous membrane was cut out to a size of 5 cm x 5 cm, which was used as a sample for air permeability measurement. Using a Garley type densometer (manufactured by Toyo Seiki Co., Ltd.), the time for 100 ml of air to pass through the sample was measured in accordance with JIS P 8117. Furthermore, as the target of the air permeability, for example, it can be set within 250 seconds or within 200 seconds. Since the lower the better, the lower limit is not particularly set, but it can be set to 30 seconds or more, for example, in consideration of the handling properties of the porous membrane sample. If the Gali air permeability is less than 250 seconds, in order to show sufficiently high ion permeability, it can be judged that it can be used as a separator for lithium-ion batteries.

＜SEM image observation of porous membrane＞ The surfaces (thin film side and air side of the substrate) of the polyimide porous membranes of Examples 5 to 8 and Comparative Example 3 were observed with a scanning electron microscope (SEM). The SEM images of the obtained air side are shown in Figure 3 ((a) Example 5, (b) Example 6, (c) Example 7, (d) Example 8), Figure 4 (Comparative Example 3). As shown in FIG. 3 , it was confirmed that in the polyimide porous membrane of the example, spherical pores of uniform size were formed in a substantially uniform distribution. As a result of measuring the diameter of the pore portion using a length measuring instrument of SEM, it was confirmed that pores having the same size as the median diameter of the resin particles used in the resin particle dispersion used in the production of the porous membrane can be formed. On the other hand, as shown in FIG. 4 , it was confirmed that in the polyimide porous membrane of Comparative Example 3, spherical pores of non-uniform size were formed in non-uniform distribution. Also, as a result of measuring the diameter of the pore portion using a length measuring instrument of SEM, it was confirmed that the median diameter of the resin particles having a larger median diameter than that of the resin particle dispersion of Comparative Example 1 used in the manufacture of the porous membrane was confirmed. empty hole.

Above, as shown in Table 2 and Figures 3 to 4, the vinyl resin particles related to the present invention can produce polyamide with high air permeability and uniform spherical voids having the same diameter as the median diameter of the particles. The imide porous film is useful as a porous material of thermosetting resin.

[Fig. 1] Fig. 1 shows electron micrographs of resin particles after a solvent resistance test ((a) Example 1, (b) Example 2, (c) Example 3, (d) Example 4). [Fig. 2] Fig. 2 shows electron micrographs of resin particles after the solvent resistance test ((a) Comparative Example 1, (b) Comparative Example 2) [ Fig. 3] Fig. 3 shows SEM images of porous membranes ((a) Example 5, (b) Example 6, (c) Example 7, (d) Example 8). [ Fig. 4] Fig. 4 shows a SEM image of a porous membrane (comparative example 3).

Claims (9)

A kind of vinyl resin particle for porous membrane production, it is derived from the structure unit (A1) of monofunctional vinyl monomer and Structural units (A2) derived from polyfunctional vinyl monomers and Vinyl resin particles for porous membrane production derived from the polymer of the structural unit (B) of the reactive emulsifier, characterized by The proportion of the structural unit (A1) is 88 to 99% by mass, the proportion of the structural unit (A2) is 0.9 to 10% by mass, and the proportion of the structural unit (B) is 0.1 to 2% by mass. A vinyl resin particle for producing a porous film comprising a structural unit (A) derived from a vinyl monomer and a compound derived from a compound represented by the following general formula (I) different from the structural unit (A) polymers of building blocks (b1),

[wherein, m represents an integer of 1 to 3, R represents a group represented by the following formula (i) or formula (ii),

(wherein, R ₁ represents a hydrogen atom or a methyl group) AO represents an ethyleneoxy group with 2 to 4 carbon atoms, n represents an integer from 0 to 100, X represents a hydrogen atom, or represents a group selected from -SO ₃ M, -COOM and -PO ₃ M (wherein, M represents an anionic hydrophilic group in the group consisting of an alkali metal atom, an alkaline earth metal atom, an ammonium group or an organic ammonium group]]. The vinyl resin particles according to claim 2, wherein the proportion of the structural unit (b1) is 0.1% by mass to 2.0% by mass relative to the total mass of the structural units of the polymer. The vinyl resin particle of claim 2 or claim 3, wherein the structural unit (A) derived from a vinylic monomer comprises a structural unit (A1) derived from a monofunctional vinylic monomer and a polyfunctional vinylic monomer It is the structural unit of monomer (A2). The vinyl resin particle according to any one of claim 1 to claim 4, wherein the median diameter of the resin particle is 0.05 μm to 2.0 μm. The vinyl resin particle of claim 1, claim 4 or claim 5, wherein the aforementioned structural unit (A1) derived from a monofunctional vinylic monomer comprises a structural unit (a1) derived from a monofunctional styrene monomer ). The vinyl resin particle according to any one of claim 1 and claim 4 to claim 6, wherein the aforementioned structural unit (A1) derived from a monofunctional vinyl monomer comprises monofunctional (meth)acryl The structural unit (a2) of the basic monomer. The vinyl resin particle according to any one of claim 1 and claim 4 to claim 7, wherein the ratio of the aforementioned polyfunctional vinyl monomer (A2) to the total mass of the aforementioned structural units of the aforementioned polymer is: 0.9% by mass to 10% by mass. A method for producing an aqueous dispersion of vinyl resin particles, characterized in that in an aqueous dispersion medium, in the presence of a polymerization initiator, emulsification polymerizes vinyl monomers, and the following general formula ( Compounds represented by I),

[wherein, m represents an integer of 1 to 3, R represents a group represented by the following formula (i) or formula (ii),

(In the formula, R ₁ represents a hydrogen atom or a methyl group), AO represents an ethyleneoxy group with 2 to 4 carbon atoms, n represents an integer from 0 to 100, X represents a hydrogen atom, or represents a group selected from -SO ₃ M, - An anionic hydrophilic group in the group consisting of COOM and -PO ₃ M (wherein, M represents an alkali metal atom, an alkaline earth metal atom, an ammonium group or an organic ammonium group)].

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