Aqueous dispersions, aqueous paints, coating films, coated articles, and methods for manufacturing aqueous dispersions.

Abstract

The present invention provides an aqueous dispersion having fluorine-containing resin particles that can provide a coating composition having excellent mechanical stability. [Solution] An aqueous dispersion containing resin particles comprising units (a) based on a fluoroolefin and at least one unit (b) selected from the group consisting of (meth)acrylic acid, salts of (meth)acrylic acid, and (meth)acrylic acid esters, and having an absolute value of the zeta potential of 52 mV or more.

Description

[Technical Field]

[0001] This disclosure relates to aqueous dispersions, aqueous paints, coatings, coated articles, and methods for producing aqueous dispersions. [Background technology]

[0002] Fluorine-containing seed polymers, which use acrylic monomers as monomers for seed polymerization, are used in a wide range of industrial fields such as the automotive industry, semiconductor industry, chemical industry, paints, battery materials, and electrical materials, as raw materials for various products or as coating film-forming components for paints, taking advantage of the weather resistance, chemical resistance, solvent resistance, heat resistance, and stain resistance of the contained fluorine polymer, and the processability, transparency, adhesion, and film-forming properties of the acrylic polymer (Patent Document 1). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2015-199943 [Overview of the project] [Problems that the invention aims to solve]

[0004] The present disclosure aims to provide an aqueous dispersion having fluorine-containing resin particles that can provide a coating composition with excellent mechanical stability. [Means for solving the problem]

[0005] This disclosure is, Unit (a) based on fluoroolefins, and, The resin particles contain at least one unit (b) selected from the group consisting of (meth)acrylic acid, (meth)acrylic acid salts, and (meth)acrylic acid esters. This aqueous dispersion is characterized by having an absolute value of 52 mV or higher for its zeta potential.

[0006] It is preferable that the resin particles have a constitutional unit (c) derived from a monomer having an oxyalkylene group copolymerized with the (b). Having such a constitutional unit (c) copolymerized with the (b) is preferable in that the water resistance and weather resistance are enhanced.

[0007] The unit (b) preferably contains a functional group in which at least a part of the —COOH groups is neutralized with a base. The fluoroolefin preferably contains at least one fluoroolefin unit selected from the group consisting of vinyl fluoride, vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene, and chlorotrifluoroethylene.

[0008] At least a part of the unit (c) has the following general formula (2) CH2=CHCH2-O-R 2 (2) (In the formula, R 2 is a hydrocarbon group having a nonionic hydrophilic group.) and is preferably a nonionic surfactant (c-1).

[0009] At least a part of the unit (c) has the following general formula (3): CH2=CHCH2-O-R 3 -X (3) (In the formula, R 3 is a hydrocarbon chain which may have an oxygen atom and / or a nitrogen atom; X is SO3Y (Y is NH4 or an alkali metal).) and is preferably an anionic surfactant (c-2).

[0010] The resin particles are preferably a fluorine seed polymer of fluoropolymer (A) particles and a monomer containing at least one unit (b) selected from the group consisting of (meth)acrylic acid, salts of (meth)acrylic acid, and (meth)acrylic acid esters. It is preferable that the result of the mechanical stability test of the aqueous dispersion is 15 minutes or more.

[0011] This disclosure also relates to an aqueous coating characterized by containing the aqueous dispersion described above. This disclosure also relates to an aqueous coating characterized by containing the above-mentioned aqueous dispersion and acrylic resin. This disclosure also relates to a coating film characterized by being obtained from the aqueous dispersion described above. This disclosure also includes a coated article containing the aforementioned coating.

[0012] This disclosure includes a step (I) for preparing fluorine-containing polymer (A) particles, and The method for producing an aqueous dispersion according to claim 1 or 2 is characterized by comprising a polymerization step (II) in which fluorine-containing polymer (A) particles, a monomer comprising at least one unit (b) selected from the group consisting of (meth)acrylic acid, (meth)acrylic acid salts and (meth)acrylic acid esters, and a constituent unit (c) derived from a monomer having an oxyalkylene group are polymerized in a liquid.

[0013] This disclosure relates to a unit (a) based on fluoroolefins, and The method for producing an aqueous dispersion is characterized by having a step (III) of neutralizing an aqueous dispersion containing resin particles comprising at least one unit (b) selected from the group consisting of (meth)acrylic acid, salts of (meth)acrylic acid, and (meth)acrylic acid esters.

[0014] This disclosure provides a step (I) for preparing fluorine-containing polymer (A) particles, Polymerization step (II) involves polymerizing fluorine-containing polymer (A) particles, a monomer comprising at least one unit (b) selected from the group consisting of (meth)acrylic acid, (meth)acrylic acid salts, and (meth)acrylic acid esters, and a constituent unit (c) derived from a monomer having an oxyalkylene group in an aqueous medium. Step (III) to neutralize the aqueous dispersion obtained in step (II). This is also a method for producing an aqueous dispersion characterized by having the following properties. [Effects of the Invention]

[0015] The aqueous dispersion of this disclosure exhibits effects such as excellent mechanical stability. [Modes for carrying out the invention]

[0016] The details of this disclosure are described below. The aqueous dispersion of this disclosure is an aqueous dispersion containing resin particles having a unit (a) based on fluoroolefin and at least one unit (b) selected from the group consisting of (meth)acrylic acid, (meth)acrylic acid salts, and (meth)acrylic esters. By having these constituent units in the same particle, the aqueous dispersion can exhibit high film-forming properties and weather resistance when used as a paint. Furthermore, by satisfying a predetermined value for the zeta potential, good water dispersibility is achieved, resulting in excellent mechanical stability.

[0017] In the aqueous dispersion of this disclosure, the resin particles constituting the dispersion may be in a form in which the polymer based on (a) and (b) above exists as a copolymer within the particles, or in a form in which a polymer (A) having unit (a) and a polymer (B) having unit (b) are mixed to form resin particles. When using the aqueous dispersion of this disclosure as a paint, it is particularly preferable that the particles be in a composite particle state from the viewpoint of the flexibility of the coating film.

[0018] The composite particles may have a core-shell structure in which a fluorine-containing polymer (A) having units (a) based on fluoroolefins forms the core, and an acrylic polymer (B) having at least one unit (b) selected from the group consisting of (meth)acrylic acid, salts of (meth)acrylic acid, and (meth)acrylic esters forms the shell, or the fluorine-containing polymer (A) and the acrylic polymer (B) may be miscible. When using the aqueous dispersion of this disclosure as a paint, it is preferable that the fluorine-containing polymer (A) and the acrylic polymer (B) are miscible from the viewpoint of transparency of the coating film.

[0019] The aqueous dispersion containing fluorine-containing composite polymer particles of this disclosure differs from aqueous dispersions formed by simply mixing polymer (A) and polymer (B). However, in the aqueous dispersion of this disclosure, polymer (A) and polymer (B) may or may not be chemically bonded.

[0020] The average particle size of the fluorine-containing polymer (A) particles is preferably 50 nm or larger, more preferably 100 nm or larger, and even more preferably 110 nm or larger, in terms of film-forming ability, water resistance, and weather resistance. Furthermore, it is preferably 300 nm or smaller, more preferably 250 nm or smaller, and even more preferably 200 nm or smaller. The average particle size is obtained by measurement using dynamic light scattering.

[0021] (Zeta potential) Zeta potential refers to the potential difference between the sliding surface in an electrical double layer and a portion sufficiently far from the interface, and represents the electrical state on the surface of resin particles in a dispersion. In this disclosure, the absolute value of such zeta potential is 52 mV or higher. When the absolute value of the zeta potential is 52 mV or higher, the electrical repulsion between dispersion particles becomes stronger, resulting in high stability of the aqueous dispersion and improved mechanical stability. Improved mechanical stability suppresses gelation during painting, providing a paint composition with excellent paintability.

[0022] The zeta potentials in this disclosure were measured using a zeta potential meter ELSZ-2000 (manufactured by Otsuka Electronics Co., Ltd.) at a set temperature of 25°C after diluting the aqueous dispersion 100-fold. The absolute value of the zeta potential is preferably 52 mV or higher, more preferably 55 mV or higher, and even more preferably 56 mV or higher. The absolute value of the zeta potential does not particularly limit the upper limit, but for example, it can be 100 mV or lower.

[0023] (Units based on fluoroolefins (a)) In the present disclosure, a fluoroolefin means an unsaturated hydrocarbon compound having at least one fluorine atom in the molecule.

[0024] Examples of the fluoroolefin include, for example, tetrafluoroethylene (TFE), hexafluoropropylene (HFP), perfluoro(alkyl vinyl ether) (PAVE),

[0025] [Chemical formula]

[0026] and other perfluoroolefins; chlorotrifluoroethylene (CTFE), vinyl fluoride (VF), vinylidene fluoride (VdF), 1,2-difluoroethylene, trifluoroethylene, trifluoropropylene, hexafluoroisobutene, 2,3,3,3-tetrafluoropropene, 1,3,3,3-tetrafluoropropene, 1,1,3,3,3-pentafluoropropene and other non-perfluoroolefins. Examples of the perfluoro(alkyl vinyl ether) include perfluoro(methyl vinyl ether) (PMVE), perfluoro(ethyl vinyl ether) (PEVE), perfluoro(propyl vinyl ether) (PPVE) and the like.

[0027] In addition, as the fluoroolefin, a functional group-containing fluoroolefin can also be used. Examples of the functional group-containing fluoroolefin include, for example, formula (1): CX 1 2=CX 2 -(Rf) m -Y 1 (1) (In the formula, Y 1 is -OH, -COOM 2 , -SO2F, -SO3M 2 (M 2 is a hydrogen atom, an NH4 group or an alkali metal), a carboxylate, a carboxyester group, an epoxy group or a cyano group; X 1 and X 2Examples include compounds represented by (0 or 1): Rf is a divalent fluorinated alkylene group or fluorinated oxyalkylene group having 1 to 40 carbon atoms, or a divalent fluorinated alkylene group or fluorinated oxyalkylene group containing an ether bond having 2 to 40 carbon atoms; m is 0 or 1).

[0028] Specific examples of the above-mentioned functional group-containing fluoroolefins include, for example,

[0029] [ka]

[0030] [ka]

[0031] These are some examples.

[0032] In addition, as the fluoroolefin mentioned above, iodized perfluorovinyl ethers such as perfluoro(6,6-dihydro-6-iodo-3-oxa-1-hexene) and perfluoro(5-iodo-3-oxa-1-pentene), as described in Japanese Patent Publication No. 5-63482 and Japanese Patent Publication No. 62-12734, can also be used.

[0033] In particular, the fluoroolefin is preferably at least one selected from the group consisting of vinyl fluoride, vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene, and chlorotrifluoroethylene. Furthermore, it is more preferable that the fluoroolefin is vinylidene fluoride and at least one selected from the group consisting of tetrafluoroethylene, hexafluoropropylene, and chlorotrifluoroethylene.

[0034] The resin particles of this disclosure preferably contain polymerization units derived from vinylidene fluoride (VdF) in that they have good weather resistance and produce a coating film with excellent transparency. The above resin particles preferably contain 40 mol% or more of polymerization units derived from VdF relative to the total amount of fluorine-containing polymer in the resin particles, more preferably 50 mol% or more, and even more preferably 70 mol% or more. Furthermore, it is preferable that the amount be 95 mol% or less.

[0035] The fluorine-containing polymer contained in the resin particles preferably contains repeating units based on vinylidene fluoride (VdF), in addition to repeating units based on tetrafluoroethylene (TFE), hexafluoropropylene (HFP), and chlorotrifluoroethylene (CTFE), and more preferably contains repeating units based on TFE and CTFE, repeating units based on TFE and HFP, repeating units based on TFE, or repeating units based on HFP.

[0036] The fluorine-containing polymer contained in the resin particles is preferably at least one fluorine-containing copolymer selected from the group consisting of VdF / TFE / CTFE copolymer, VdF / TFE copolymer, VdF / TFE / HFP copolymer, VdF / CTFE copolymer, and VdF / HFP copolymer and PVdF, with VdF / TFE / CTFE = 40~99 / 1~50 / 0~30 (mol%), VdF / TFE = 50~99 / 1~50 (mol%), VdF / TFE / HFP = 45~99 / 0~35 / 5~50 (mol%), VdF / CTFE = 40~99 / 1~30 (mol%), and VdF / HFP = 50~99 / 1~50 (mol%) being more preferable.

[0037] In the fluorine-containing polymer (A) contained in the resin particles, the fluorine element content is preferably 40 to 80% by mass, and more preferably 50 to 70% by mass, considering the weather resistance of the resulting coating film and the compatibility of polymer (A) with acrylic.

[0038] ((b)) at least one unit selected from the group consisting of (meth)acrylic acid, (meth)acrylic acid salts, and (meth)acrylic acid esters. The salt of (meth)acrylic acid is not particularly limited and can be an ammonium salt, an amine salt, an alkali metal salt, etc.

[0039] The above acrylic acid ester or methacrylic acid ester is preferably an alkyl acrylate ester or an alkyl methacrylate ester having 1 to 10 carbon atoms in the alkyl group. Examples of alkyl acrylates and alkyl methacrylates include alkyl (meth)acrylates such as methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, methyl methacrylate, n-propyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isopropyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, cyclohexyl acrylate, and cyclohexyl methacrylate. Furthermore, the alkyl acrylate or alkyl methacrylate may also be a hydroxyl group-containing acrylic monomer having a hydroxyl group and a (meth)acryloyl group in its molecule, such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, or 4-hydroxybutyl methacrylate. These acrylic acid esters or methacrylic acid esters may be used individually or in combination of two or more, and are preferably n-butyl acrylate and methyl methacrylate.

[0040] Furthermore, the (meth)acrylic acid ester may have a reactive functional group such as a hydroxyl group. The (meth)acrylic acid ester having such a reactive functional group is not particularly limited, and examples include 2-hydroxyethyl (meth)acrylate and 2-hydroxybutyl (meth)acrylate.

[0041] The above unit (b) is preferably contained in a proportion of 20 to 80% by mass relative to the total amount of polymer constituting the resin particles. More preferably, it is contained in a proportion of 30 to 70% by mass. This range is preferable because it allows for high film-forming properties and weather resistance of the coating film when the aqueous dispersion of this disclosure is used as a paint.

[0042] The polymer containing the above unit (b) preferably has both a (meth)acrylic acid salt and a (meth)acrylic acid ester. In particular, since a (meth)acrylic acid salt greatly affects the surface zeta potential, the objectives of this disclosure can be more favorably achieved by introducing such a functional group in an appropriate amount.

[0043] Polymers having constituent units based on the above-mentioned salts of (meth)acrylic acid are generally obtained by neutralizing a polymer with (meth)acrylic acid as a constituent unit with a basic compound. Therefore, during this neutralization, all of the constituent units derived from (meth)acrylic acid may be neutralized, or only some of them may be neutralized.

[0044] The resin in the aqueous dispersion of the present disclosure preferably has an acid value of 0.5 to 20.0. The lower limit of the above acid value is more preferably 1.0, and even more preferably 2.0. The upper limit of the above acid value is more preferably 15, and even more preferably 10. The acid group here may be derived from the (meth)acrylic acid described above, or from other constituent units having a carboxyl group.

[0045] (Constituent unit (c) derived from monomers containing an oxyalkylene group) In this disclosure, the polymer containing unit (b) may further have a constituent unit (c) derived from a monomer having an oxyalkylene group. Having such a constituent unit (c) derived from a monomer having an oxyalkylene group makes it easier for the zeta potential to fall within a predetermined range. It is also acceptable for the polymer containing unit (a) to have a constituent unit (c). The monomer having an oxyalkylene group is preferably a monomer having an ethenyl group, with an oxyalkylene group in the side chain of the monomer. Having such a structure allows it to function as a reactive emulsifier, and emulsion stability can be obtained by introducing a hydrophilic group into a hydrophobic resin structure. Using a reactive emulsifier as described above is preferable because it chemically bonds with the acrylic more effectively than when using a non-reactive emulsifier, resulting in a coating with higher water resistance and weather resistance.

[0046] The oxyalkylene group is [ka] (In the formula, R 10 (This refers to an alkylene group with 4 or fewer carbon atoms.) It is preferable that the structure is a (poly)alkylene oxide chain as represented by . It is preferable that the structural unit is based on such a (poly)alkylene oxide chain and monomers having unsaturated bonds. The repeating unit n in the above general formula can be 1 to 39. Examples of the alkylene oxides mentioned above include linear or branched oxyalkylene groups having 2 to 4 carbon atoms, such as ethylene oxide, propylene oxide, and butylene oxide. These may also be copolymerized chains.

[0047] In this disclosure, it is more preferable that n is within the range of 1 to 30. By using an emulsifier with a small number of added alkylene oxide units, the hydrophilicity of the particle surface is reduced, and the amount of lipophilic functional groups (such as carboxyl groups) on the particle surface is increased. This is preferable because the increased charge on the particle surface increases the repulsive force between particles, thus stabilizing the particles.

[0048] The constituent unit (c) derived from the monomer having an oxyalkylene group does not particularly limit its structure, but examples include those that act as anionic surfactants and those that act as nonionic surfactants. It is most preferable to use these in combination. The following describes nonionic surfactants (c-1) and anionic surfactants (c-2).

[0049] (Nonionic surfactant (c-1)) The nonionic surfactant (c-1) is not particularly limited; for example, Formula (2): CH2=CHCH2-OR 2 (2) Examples of nonionic surfactants include those shown in [the provided text].

[0050] In the formula, R 2 It is a hydrocarbon group having a nonionic hydrophilic group. The above R 2 It is preferable that this is a hydrocarbon chain containing the oxyalkylene group described above.

[0051] More specifically, the compound represented by formula (2) is formula (c1):

[0052] [ka]

[0053] (In the formula, R 1’A hydrocarbon chain that is linear or branched and may contain an oxygen atom, a phenyl group, or a phenylene group; n is an integer from 1 to 100. A compound represented by (c-1-1) is preferred. R 1’ The number of carbon atoms is preferably 1 to 51, more preferably 5 to 26, and even more preferably 10 to 21. n is an integer between 1 and 100, preferably between 1 and 60, and more preferably between 10 and 30.

[0054] The compound represented by formula (c1) is given by the following formula (c1-1);

[0055] [ka]

[0056] (In the formula, R 3’ A compound represented by (c-1-1) is preferably a hydrocarbon chain having 1 to 50 carbon atoms, which may contain a phenyl group or a phenylene group; n is an integer from 1 to 100.

[0057] In equation (c1-1), R 3’ The carbon atoms have 1 to 50 carbon atoms, preferably 5 to 25, and more preferably 10 to 20. n is an integer between 1 and 100, preferably between 1 and 60, and more preferably between 10 and 30.

[0058] (Anionic surfactant (c-2)) The anionic surfactant (c-2) is not particularly limited; for example, Formula (3): CH2=CHCH2-OR 3 Examples of anionic surfactants (c-2-1) represented by -X (3) can be listed.

[0059] R in equation (3) above 3 It is preferable that this is a hydrocarbon chain containing the oxyalkylene group described above. X is SO3Y (where Y is NH4 or an alkali metal). Na and K are preferred alkali metals.

[0060] More specifically, a compound represented by formula (3) is, for example, formula (c2-1):

[0061] [ka]

[0062] (In the formula, R 2’ A compound represented by (c-2-2) is preferably a linear or branched hydrocarbon chain which may contain an oxygen atom, a phenyl group, or a phenylene group; n is an integer from 1 to 100; X is SO3Y (where Y is NH4 or an alkali metal atom). In the above compound (c-2-2), R 2’ The number of carbon atoms is preferably 1 to 51, more preferably 5 to 21, and even more preferably 10 to 16. n is preferably an integer between 1 and 60, more preferably an integer of 5 or more, even more preferably an integer of 10 or more, more preferably an integer of 40 or less, and even more preferably an integer of 30 or less. Na and K are preferred as the alkali metal atoms mentioned above.

[0063] The compound represented by formula (c2-1) is shown in the following formula (c2-2):

[0064] [ka]

[0065] (In the formula, R 5’ A compound represented by (c-2-3) (c-2-3), or the following formula (c-2-3); is a linear or branched hydrocarbon chain having 1 to 50 carbon atoms, which may contain a phenyl group or a phenylene group; n is an integer from 1 to 100; X is SO3Y (where Y is NH4 or an alkali metal atom, e.g., Na, K);

[0066] [ka]

[0067] (In the formula, R 4’ A compound represented by (c-2-4) is preferably an alkyl group having 1 to 50 carbon atoms; n is an integer from 1 to 100; and X is SO3Y (where Y is NH4 or an alkali metal atom, such as Na or K).

[0068] In equation (c2-2), R 5’ The carbon atom (C) preferably has 1 to 50 carbon atoms, more preferably 5 to 20, and even more preferably 10 to 15 carbon atoms. n is an integer from 1 to 100, preferably an integer from 1 to 60, more preferably an integer from 5 to 35, and even more preferably an integer from 10 to 30, from the viewpoint of dispersion stability and water resistance.

[0069] In equation (c2-3), R 4’ The C1 is preferably an alkyl group having 1 to 50 carbon atoms, more preferably 5 to 20, and even more preferably 10 to 15. The C2 is preferably an integer from 1 to 100, and more preferably an integer from 1 to 30 from the viewpoint of dispersion stability and water resistance. The C3 is preferably SO3NH4.

[0070] The above-mentioned constituent unit (c) is preferably 0.1 to 10.0 parts by mass per 100 parts by mass of solids in the aqueous dispersion of the present disclosure. If the amount of constituent unit (c) is too small, the dispersion stability of the emulsion particles may decrease, and if the amount added is too large, the water resistance and weather resistance of the resulting coating film may decrease. The content of the above-mentioned constituent unit (c) is more preferably 0.5 parts by mass or more, even more preferably 1.0 part by mass or more, even more preferably 5.0 parts by mass or less, and even more preferably 3.0 parts by mass or less.

[0071] In the aqueous dispersion of this disclosure, it is preferable to use both a nonionic surfactant (c-1) and an anionic surfactant (c-2) as constituent unit (c). This is preferable from the viewpoint of improving the chemical stability, storage stability, freezing stability, transport stability, paint formation stability, etc., of the aqueous dispersion particles. In this case, it is preferable that the nonionic component constitutes 20 to 80 parts by mass of the total amount of constituent unit (c) in order to maintain higher dispersion stability and water resistance and weather resistance of the coating film.

[0072] The resin contained in the aqueous dispersion of this disclosure may have units other than the above units (a), (b), and (c) (hereinafter referred to as unit (d)). The above unit (d) may be any monomer having a radically polymerizable ethylenically unsaturated bond that does not fall under the above units (a), (b), or (c). Examples include unsaturated carboxylic acids other than (meth)acrylic acid, hydrolyzable silyl group-containing monomers, hydroxyl group-containing alkyl vinyl ethers, vinyl carboxylate esters, and α-olefins.

[0073] Specific examples of unsaturated carboxylic acids other than (meth)acrylic acid mentioned above include vinyl acetic acid, crotonic acid, cinnamic acid, 3-allyloxypropionic acid, 3-(2-alyloxyethoxycarbonyl)propionic acid, itaconic acid, itaconic acid monoester, maleic acid, maleic acid monoester, maleic anhydride, fumaric acid, fumaric acid monoester, vinyl phthalate, vinyl pyromellitic acid, and undecylenic acid. Among these, at least one selected from the group consisting of acrylic acid, methacrylic acid, vinyl acetic acid, crotonic acid, itaconic acid, maleic acid, maleic acid monoester, fumaric acid, fumaric acid monoester, 3-allyloxypropionic acid, and undecylenic acid is preferred due to its low homopolymerizability, making it difficult to form homopolymers, and its ease of controlling the introduction of carboxyl groups.

[0074] The above hydrolyzable silyl group-containing monomers include: CH2=CHCOO(CH2)3Si(OCH3)3, CH2=CHCOO(CH2)3Si(CH3)(OCH3)2, CH2=CHCOO(CH2)3Si(OC2H5)3, CH2=CHCOO(CH2)3Si(CH3)(OC2H5)2, CH2=C(CH3)COO(CH2)3Si(OCH3)3, CH2=C(CH3)COO(CH2)3Si(CH3)(OCH3)2, CH2=C(CH3)COO(CH2)3Si(OC2H5)3, CH2=C(CH3)COO(CH2)3Si(CH3)(OC2H5)2, CH2=C(CH3)COO(CH2)2O(CH2)3Si(OCH3)3, CH2=C(CH3)COO(CH2)2(CH2)3Si(CH3)(OCH3)2, CH2=C(CH3)COO(CH2) 11 Si(OCH3)3, CH2=C(CH3)COO(CH2) 11 Si(CH3)(OCH3)2, These are some examples. These hydrolyzable silyl group-containing monomers may be used individually or in combination of two or more.

[0075] In terms of good water resistance, resistance to hot water, and storage stability, at least one selected from the group consisting of γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropyltriethoxysilane, and γ-methacryloxypropylmethyldiethoxysilane is preferred, and γ-methacryloxypropyltriethoxysilane is more preferred.

[0076] Examples of the hydroxyl group-containing alkyl vinyl ethers mentioned above include 2-hydroxyethyl vinyl ether, 3-hydroxypropyl vinyl ether, 2-hydroxypropyl vinyl ether, 2-hydroxy-2-methylpropyl vinyl ether, 4-hydroxybutyl vinyl ether, 4-hydroxy-2-methylbutyl vinyl ether, 5-hydroxypentyl vinyl ether, 6-hydroxyhexyl vinyl ether, 2-hydroxyethyl allyl ether, 4-hydroxybutyl allyl ether, and glycerol monoallyl ether. At least one selected from the group consisting of 4-hydroxybutyl vinyl ether and 2-hydroxyethyl vinyl ether is preferred due to its excellent polymerization reactivity.

[0077] Examples of vinyl carboxylate esters include vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl caproate, vinyl versatate, vinyl laurate, vinyl stearate, vinyl cyclohexylcarboxylate, vinyl benzoate, and p-t-butylbenzoate. By using vinyl carboxylate esters, properties such as improved gloss and increased glass transition temperature can be imparted to coating films using fluorine-containing seed polymers obtained from this disclosure.

[0078] Examples of α-olefins include ethylene, propylene, n-butene, isobutene, and styrene. By using α-olefins, properties such as improved flexibility can be imparted to coating films using fluorine-containing seed polymers obtained from this disclosure.

[0079] (Method for producing aqueous dispersions) The method for producing the aqueous dispersion disclosed herein is: (I) A step of preparing fluorine-containing polymer (A) particles, and (II) A manufacturing method comprising the step of seed polymerization of unit (b) to fluorine polymer (A) particles in an aqueous dispersion of fluorine polymer (A) particles in the presence of constituent unit (c) derived from monomers having oxyalkylene groups.

[0080] Furthermore, a method for producing an aqueous dispersion is also part of this disclosure, comprising a step (III) of neutralizing an aqueous dispersion containing resin particles comprising a unit (a) based on a fluoroolefin, at least one unit (b) selected from the group consisting of (meth)acrylic acid, salts of (meth)acrylic acid and (meth)acrylic acid esters, and a constituent unit (c) derived from a monomer having an oxyalkylene group. Furthermore, a method for producing an aqueous dispersion that includes all of these steps is also part of this disclosure. The following details this manufacturing method.

[0081] (Process (I)) Step (I) described above is a step of preparing fluorine-containing polymer (A) particles. Such a step may involve obtaining fluorine-containing polymer (A) particles by polymerization, or it may involve purchasing commercially available fluorine-containing polymer (A) and preparing it. Furthermore, it is preferable that the fluorine-containing polymer (A) particles are in the form of an aqueous dispersion in which such particles are dispersed in water. In step (I), it is preferable to carry out aqueous dispersion polymerization of the above-mentioned fluoroolefin-based unit (a). Examples of aqueous dispersion polymerization include emulsion polymerization and suspension polymerization, with emulsion polymerization being particularly preferred because it generates a large number of polymer particles with small particle sizes.

[0082] In step (I), an emulsifier may be used from the viewpoint of efficiently producing the fluorine-containing polymer (A). Such emulsifiers are not particularly limited and include general surfactants used in the polymerization of fluorine monomers.

[0083] The amount of surfactant used is preferably 10 to 5000 ppm, and more preferably 20 to 4000 ppm, relative to the total amount of water in the case of emulsion polymerization. If the amount of surfactant used is less than 10 ppm, the surfactant activity tends to decrease and the number of generated particles tends to decrease.

[0084] There are no particular restrictions on the polymerization temperature, and the optimal temperature is adopted according to the type of polymerization initiator. A temperature of 40 to 120°C, and more preferably 50 to 100°C, is preferred because it maintains a high monomer density in the gas phase, suppresses polymer branching reactions, and facilitates the efficient acquisition of the desired copolymer. The monomers may be supplied continuously or sequentially.

[0085] While oil-soluble peroxides can also be used as polymerization initiators, it is preferable to use water-soluble radical polymerization initiators because they offer superior stability for fluoropolymer formation and particle formation during polymerization. Preferred water-soluble radical polymerization initiators include, for example, persulfuric acid, perboric acid, perchloric acid, superphosphate, and ammonium, potassium, and sodium salts of percarbonate, with ammonium persulfate and potassium persulfate being particularly preferred.

[0086] The amount of polymerization initiator added is not particularly limited, but it should be an amount sufficient to avoid a significant decrease in the polymerization rate (for example, a few ppm relative to water concentration) and added all at once, sequentially, or continuously at the beginning of polymerization. The upper limit is the range within which the heat of the polymerization reaction can be removed from the apparatus surface.

[0087] In step (I), molecular weight modifiers may be added. The molecular weight modifiers may be added all at once at the beginning, or they may be added continuously or in stages.

[0088] Examples of molecular weight modifiers include esters such as dimethyl malonate, diethyl malonate, methyl acetate, ethyl acetate, butyl acetate, and dimethyl succinate, as well as isopentane, isopropanol, acetone, various mercaptans, carbon tetrachloride, cyclohexane, monoiodomethane, 1-iodomethane, 1-iodopropane, isopropyl iodide, diiodomethane, 1,2-diiodomethane, and 1,3-diiodopropane.

[0089] Other buffering agents may be added as appropriate, but it is preferable to use them in amounts that do not impair the effects of the present disclosure.

[0090] The polymerization pressure can be appropriately selected within the range of 0.1 to 10 MPa, or even 0.2 to 8 MPa, and within this range, both low pressure (0.1 to 1 MPa) and high pressure (1 to 10 MPa) are acceptable.

[0091] As a stirring method, anchor blades, turbine blades, and inclined blades can be used, but stirring with large blades called full zone or max blend is preferred because it provides good monomer diffusion and polymer dispersion stability. The stirring device can be either a horizontal or vertical stirring device.

[0092] In step (I) of this disclosure, the concentration of the fluorine-containing polymer in the polymerization product solution may be increased. For example, the fluorine-containing polymer concentration may be higher than approximately 45% by mass, for example, an aqueous dispersion of the fluorine-containing polymer with a concentration of 45-55% by mass.

[0093] The fluorine-containing polymer (A) particles obtained in step (I) have an average particle diameter of 30-200 nm and a number-average molecular weight of 1.0 × 10⁻⁶ 4 ~1.0×10 6 Furthermore, it is preferable that the molecular weight distribution (Mw / Mn) is sharp, around 2 to 5. The number of particles in the aqueous dispersion is 1 × 10⁶. 14 ~5×10 16 It is preferable that the amount is (1g / 1g of water). The average particle diameter is a value obtained by measurement using the dynamic scattering method. The number-average molecular weight and molecular weight distribution can be measured by gel permeation chromatography (GPC).

[0094] In the aqueous dispersion of this disclosure, the average particle size of the resin particles is preferably 300 nm or less, in order to ensure high gloss and high sedimentation stability during storage when used as a paint composition. For this reason, the average particle size of the resin particles in the dispersion obtained by step (I) is preferably 200 nm or less, and more preferably 150 nm or less, taking into consideration subsequent seed polymerization. On the other hand, the average particle size of the resin particles in the dispersion obtained by step (I) is preferably 30 nm or more, and more preferably 50 nm or more, from the viewpoint of maintaining high polymerization stability even when the amount of surfactant used, which is related to water resistance and weather resistance, is reduced.

[0095] (Step (II)) Step (II) is a step in which a monomer composition essential for unit (b) is aqueous dispersion polymerized in an aqueous dispersion of fluorine-containing polymer (A) particles obtained in Step (I) in the presence of constituent unit (c) derived from a monomer having an oxyalkylene group, wherein the fluorine-containing polymer (A) particles obtained in Step (I) are used as seed particles to seed polymerize a monomer composition essential for unit (b), which is a monomer for seed polymerization, to obtain an aqueous dispersion containing resin particles.

[0096] In step (II), it is preferable to use in combination an anionic surfactant (c-2) represented by formula (3) and a nonionic surfactant (c-1) represented by formula (2) as surfactants. When an aqueous dispersion containing fluorine-containing seed polymer particles obtained by using these in combination is used as a paint, a coating film with excellent water resistance and weather resistance can be formed.

[0097] Seed polymerization can be carried out by generally known methods. For example, one method involves adding a monomer composition containing the above-mentioned unit (b) and a polymerization initiator to an aqueous dispersion of fluorine polymer (A) particles in the presence of an anionic surfactant (c-2) and a nonionic surfactant (c-1), and then performing emulsion polymerization.

[0098] The polymerization initiators mentioned above are not particularly limited as long as they can be subjected to a free radical reaction in water, and in some cases, they can be used in combination with reducing agents. Examples of usable water-soluble polymerization initiators include persulfates and hydrogen peroxide, with persulfates being preferred. Examples of persulfates include ammonium persulfate, sodium persulfate, and potassium persulfate, with ammonium persulfate being more preferred. Examples of usable reducing agents include sodium pyrosulfite, sodium bisulfite, sodium L-ascorbate, and rongalit. Examples of oil-soluble polymerization initiators include diisopropyl peroxydicarbonate (IPP), benzoyl peroxide, dibutyl peroxide, and azobisisobutyronitrile (AIBN). The amount of polymerization initiator used is preferably 0.0001 to 2.0 parts by mass per 100 parts by mass of monomer for seed polymerization.

[0099] The polymerization temperature may be 10 to 90°C, and the polymerization time may be 0.5 to 6 hours.

[0100] In addition, generally known additives used in emulsion polymerization, such as surfactants, may be used.

[0101] The fluorine-containing seed polymer (B) particles obtained in step (II) preferably have an average particle diameter of 110 to 300 nm.

[0102] The resin particles in the aqueous dispersion of the present disclosure preferably have a weight ratio (a) / (c) of polymer of unit (a) to polymer of unit (c) contained in the resin particles of 65 / 35 to 10 / 90, more preferably 60 / 40 to 20 / 80, and even more preferably 55 / 45 to 25 / 75.

[0103] The above resin particles preferably have a fluorine content of 5 to 50% by mass, and more preferably 10 to 46% by mass.

[0104] The resin particles described above preferably contain 50 to 900% by mass of unit (b) relative to unit (a). When an aqueous dispersion of the resin particles is applied to a paint composition, a more preferable upper limit is 400% by mass, which results in better weather resistance of the resulting coating film, and a more preferable lower limit is 70% by mass, which results in good flexibility and blocking resistance.

[0105] Furthermore, in the above case, it is preferable that the resin particles contain 0 to 4% by mass of polymerization units based on other copolymerizable radical polymerizable monomers having ethylenically unsaturated bonds, relative to the content of unit (b). More preferably, it is 0.1 to 3% by mass, and even more preferably 0.1 to 2.5% by mass. Other copolymerizable monomers having ethylenically unsaturated bonds that are radically polymerizable include the hydroxyl group-containing alkyl vinyl ethers, vinyl carboxylates, and α-olefins mentioned above.

[0106] The polymer constituting the above resin particles preferably has a glass transition temperature of 10 to 50°C, and more preferably 20 to 45°C. The glass transition temperature can be determined using a differential scanning calorimeter (DSC).

[0107] (Process (III)) As described above, the method for producing the aqueous dispersion of the present disclosure may include a step (III) of neutralizing an aqueous dispersion containing resin particles comprising a unit (a) based on a fluoroolefin, at least one unit (b) selected from the group consisting of (meth)acrylic acid, salts of (meth)acrylic acid and (meth)acrylic acid esters, and a constituent unit (c) derived from a monomer having an oxyalkylene group.

[0108] The neutralization described above is preferably performed stoichiometrically, according to the amount of base added to the -COOH group present in the resin. However, the -COOH group in the resin is located within the resin chain and is not exposed to the outside, which can sometimes hinder the neutralization reaction. In such cases, carrying out the neutralization reaction at a relatively high temperature is preferable because it increases molecular motion, making the neutralization reaction more likely to occur.

[0109] Step (III) described above does not particularly limit the aqueous dispersion to be treated, but it is particularly preferable to perform step (III) on the aqueous dispersion obtained by steps (I) and (II) above. Examples of neutralizing agents used for neutralization include ammonia; organic amines such as diethylamine, ethylethanolamine, diethanolamine, monoethanolamine, monopropanolamine, isopropanolamine, ethylaminoethylamine, hydroxyethylamine, diethylenetriamine, and triethylamine; inorganic neutralizing agents such as sodium bicarbonate, ammonium hydroxide or alkali metal hydroxides, such as lithium hydroxide, sodium hydroxide, and potassium hydroxide, or alkaline earth metal hydroxides, such as magnesium hydroxide and calcium hydroxide, and zinc oxide. Of these, ammonia and baking soda are particularly advantageous in terms of availability, emulsion stability, and ease of handling.

[0110] (Method for adjusting zeta potential) In the aqueous dispersions of this disclosure, it is important that the absolute value of the zeta potential is 52 mV or higher. Methods for obtaining an aqueous dispersion having such a specific absolute value of zeta potential include selecting the emulsifier to be used and preparing the resin composition of the polymer.

[0111] Furthermore, after polymerization, the acidic groups present in the polymer are often neutralized to increase its affinity for water. The content of these acidic groups and the conditions for their neutralization are also important factors.

[0112] When neutralizing acidic groups after polymerization, it is preferable that this neutralization proceeds more smoothly and that a high proportion of the acidic groups are neutralized. In particular, acidic groups in the resin are surrounded by resin chains, which can sometimes hinder the neutralization reaction. In such cases, allowing neutralization to proceed to a higher proportion can increase the zeta potential and result in a more stable product.

[0113] Therefore, the neutralization temperature for the neutralization reaction is preferably 20 to 80°C, and more preferably 50 to 70°C. Neutralization at such temperatures allows the reaction to proceed smoothly. This makes it possible to easily obtain an aqueous dispersion having the desired zeta potential in this disclosure.

[0114] (Mechanical stability test) The aqueous dispersions of this disclosure preferably have a mechanical stability test result of 15 minutes or more. The above-mentioned "mechanical stability test result of 15 minutes or more" means that, when the mechanical stability test described below is performed, the time from the start of stirring until the rotation speed increases by 50% or more is 15 minutes or more. A mechanical stability test result of 15 minutes or more is preferable as it is an indicator of good storage stability.

[0115] (Application) The aqueous dispersions obtained in this disclosure can be applied as is or with appropriate modifications to various applications. Typical applications include, for example, various paints, particularly aqueous paint compositions, and molding materials for films and sheets.

[0116] (water-based paint) The aqueous dispersion of this disclosure can be used as is, or as an aqueous paint by adding the necessary components for a paint. Other than using the aqueous dispersion of this disclosure as a film-forming agent, conventionally known additives and mixing ratios can be used. For example, the aqueous paint preferably contains the above aqueous dispersion in such a way that the resin particles therein amount to 10 to 60% by mass.

[0117] Furthermore, the aqueous dispersion of this disclosure may be mixed with other resins to form an aqueous paint. Among the other resins, acrylic resin is most preferred from the viewpoint of compatibility with the aqueous dispersion. A water-based coating containing such an aqueous dispersion of the present disclosure is also one of the preferred embodiments of the present disclosure. The coating film formed using the above-mentioned water-based paint exhibits excellent water resistance and weather resistance.

[0118] When applied to a pigment-containing water-based paint, for example, a predetermined amount of pigment dispersion, in which water, a pigment such as titanium dioxide, an antifoaming agent, a pigment dispersant, a pH adjuster, etc., are dispersed in a pigment disperser such as a sand mill, and a predetermined amount of film-forming aid is stirred and mixed with the water-based dispersion of the present disclosure, then a predetermined amount of thickener is added and mixed, and other necessary additives are added as appropriate. When preparing a water-based paint without pigment, water, a film-forming aid, an antifoaming agent, a thickener, a pH adjuster, and other necessary additives are added to the water-based dispersion of the present disclosure as needed and stirred and mixed in a known manner.

[0119] For paint applications, additives such as film-forming aids, antifreezes, pigments, fillers, pigment dispersants, defoamers, leveling agents, rheology modifiers, preservatives, UV absorbers, antioxidants, matting agents, lubricants, and crosslinking agents may be added as needed.

[0120] Various commercially available film-forming aids can be used as the above-mentioned film-forming aids. Specifically, examples include, but are not limited to, polyhydric alcohol alkyl ethers and organic acid esters such as dipropylene glycol-n-butyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, diethylene glycol diethyl ether, ethylene glycol mono-2-ethylhexyl ether, diethyl adipate, and 2,2,4-trimethylpentane-1,3-diol monoisobutyrate.

[0121] Known methods and conditions can be used to apply the above-mentioned water-based paint. For example, one method involves applying the paint to a substrate using methods such as spray coating, roll coating, flow coating, roller or brush painting to form a paint film, and then drying it at 5 to 200°C. By such a method, it is possible to form a paint film that has excellent weather resistance, gloss, and transparency, with minimal foaming, high resistance to hot water, and does not easily deteriorate even when subjected to repeated freezing and thawing.

[0122] A coating film formed by applying the above-mentioned aqueous paint and a coated article having said coating film are also preferred embodiments of this disclosure. Coated articles obtained by applying the above-mentioned aqueous paint composition can be used in a wide range of applications. For example, the interior and exterior of electrical appliances (microwave ovens, toasters, refrigerators, washing machines, hair dryers, televisions, video players, amplifiers, radios, electric kettles, rice cookers, radio cassette players, cassette decks, compact disc players, video cameras, etc.), the interior and exterior of air conditioners such as indoor units, outdoor units, outlets and ducts, air purifiers, and heaters, lighting fixtures such as fluorescent lamps, chandeliers, and reflectors, furniture, machine parts, decorative items, combs, eyeglass frames, natural fibers, synthetic fibers (threads and fabrics obtained therefrom), and the interior and exterior of office equipment (telephones, facsimile machines, photocopiers (including rolls), cameras, overhead projectors, document cameras, clocks, slide projectors, desks, bookshelves, lockers, filing cabinets, chairs, bookends, electronic whiteboards, etc.). It has a wide range of applications, including painting automobiles (wheels, door mirrors, moldings, door handles, license plates, steering wheels, instrument panels, etc.) and kitchen appliances (range hoods, sinks, countertops, knives, cutting boards, faucets, gas ranges, ventilation fans, etc.), painting interior partitions, bathroom units, shutters, blinds, curtain rails, accordion curtains, walls, ceilings, floors, etc., and exterior applications such as exterior walls, handrails, gates, shutters, and other exterior parts of general houses and buildings, as well as exterior building materials such as ceramic sizing materials, foamed concrete panels, concrete panels, aluminum curtain walls, steel plates, galvanized steel plates, stainless steel plates, PVC sheets, PET films, polycarbonate, and acrylic films, as well as sizing materials, window glass, and more. In particular, because the water-based paint of this disclosure has excellent weather resistance and water resistance, it is preferably used for painting building exterior materials, and is preferably used as a heat-shielding paint for roofs and exterior walls, or as a water-resistant paint for concrete exterior walls.

[0123] While embodiments of this disclosure have been described above, it will be understood that a variety of modifications to the form and details are possible without departing from the spirit and scope of the claims. [Examples]

[0124] The present disclosure will be specifically explained below with reference to examples, but the present disclosure is not limited to these examples. In the following examples, unless otherwise specified, "parts" and "%" represent "parts by mass" and "% by mass," respectively.

[0125] Example 1 In a separable flask equipped with a thermometer, dropping funnel, reflux tubing, and stirrer, 936 g of an aqueous dispersion (solid content concentration 45.5% by mass) of particles of fluorine-containing polymer (A) (VdF / TFE / CTFE copolymer (=72.1 / 14.9 / 13 (mol%)) (VTC) and ammonium = {α-[1-(allyloxy)methyl]alkyl (a mixture of C=11 and 13, and limited to those including linear and branched types)}-ω-(sulfonatooxy) poly(n=1~30 (oxyethylene)) as the main component, {2-alkyl (a mixture of C=10 and 12, and limited to those including linear and branched types)) oxysilane, oxysilane and 17.4 g of Aqualon KH1025(c-2), which is the reaction product of the reaction product of propa-2-en-1-ol and sulfamic acid, and 22 g of Adekarya soap ER-20(c-1), which is an oxirane polymerization adduct of {alkanol (C=10~14, branched type) and 1-(allyloxy)-2,3-epoxypropane} with an EO value of 20, mainly composed of {α-[2-(allyloxy)1-({[alkyl(C=10~14)]oxy}methyl)ethyl]-ω-hydroxypoly(n=1~100)(oxyethylene), were added to an aqueous solution of 33 g of pure water, and the mixture was stirred for 15 minutes, then heated to an internal temperature of 80°C.

[0126] Here, 144 g of methyl methacrylate (MMA), 121 g of n-butyl acrylate (n-BA), 2.7 g of acrylic acid (AA), 0.3 g of N-dodecyl mercaptan, 80 g of pure water, 17.4 g of (c-2), and 4.6 g of (c-1) were dissolved in 6.9 g of pure water and mixed to create an aqueous solution, which was then pre-emulsified. To this emulsion, an aqueous solution of 0.9 g of ammonium persulfate dissolved in 22 g of pure water was mixed and placed in a dropping funnel. Polymerization was carried out by dropping the mixture into the separable flask over 3 hours. After aging at 80°C, the reaction solution was cooled to room temperature (20-30°C) to terminate the reaction. After neutralization with 19 g of saturated sodium bicarbonate solution, the pH was adjusted to 7-8 using a 28% aqueous ammonia solution to obtain an aqueous dispersion of resin particles (solid content concentration 50% by mass). The average particle size of the resin particles in the obtained aqueous dispersion was 159 nm.

[0127] Example 2 In a separable flask equipped with a thermometer, dropping funnel, reflux tubing, and stirrer, 936 g of an aqueous dispersion of fluorine-containing polymer (A) adjusted to a solid content concentration of 43.5% by mass, and an aqueous solution of (c-2) 17.4 g, (c-1) 14 g, and 19 g of pure water were added. After stirring for 15 minutes, the mixture was heated and the internal temperature was raised to 80°C.

[0128] Here, 144 g of methyl methacrylate (MMA), 121 g of n-butyl acrylate (n-BA), 2.7 g of acrylic acid (AA), 0.3 g of N-dodecyl mercaptan, 80 g of pure water, 17.4 g of (c-2), and 4.6 g of (c-1) were dissolved in 6.9 g of pure water as acrylic monomers, and the resulting aqueous solution was mixed and pre-emulsified. To this emulsion, an aqueous solution of 0.9 g of ammonium persulfate dissolved in 22 g of pure water was mixed and placed in a dropping funnel, and polymer was carried out by dropping it into the separable flask over 3 hours. After aging at 80°C, the reaction solution was cooled to room temperature to terminate the reaction. After neutralization with 19 g of saturated sodium bicarbonate solution, the pH was adjusted to 7-8 using a 28% aqueous ammonia solution to obtain an aqueous dispersion of fluorine-containing seed polymer (B) particles (solid content concentration 50% by mass). The average particle size of the obtained fluorine-containing seed polymer (B) particles was 149 nm.

[0129] Example 3 In a separable flask equipped with a thermometer, dropping funnel, reflux tubing, and stirrer, 1170 g of an aqueous dispersion of fluorine-containing polymer (A) adjusted to a solid content concentration of 43.5% by mass, and an aqueous solution of (c-2) 21.8 g, (c-1) 28 g, and 40.8 g of pure water were added. After stirring for 15 minutes, the mixture was heated and the internal temperature was raised to 80°C.

[0130] Here, 180g of methyl methacrylate (MMA), 151g of n-butyl acrylate (n-BA), 3.4g of acrylic acid (AA), 0.4g of N-dodecyl mercaptan, 89g of pure water, 21.8g of (c-2), and 5.8g of (c-1) were mixed with 8.6g of pure water to create an aqueous solution, which was then pre-emulsified. This emulsion was mixed with an aqueous solution of 0.9g of ammonium sulfate dissolved in 22g of pure water, placed in a dropping funnel, and added dropwise to the separable flask over 3 hours to allow polymerization to proceed. After that, it was aged at 80°C for 1 hour. The reaction solution was cooled to 70°C, neutralized with 19g of saturated sodium bicarbonate solution, and then the pH was adjusted to 7-8 using a 28% aqueous ammonia solution. After that, it was cooled to room temperature to obtain an aqueous dispersion of fluorine-containing seed polymer (B) particles (solid content concentration 50% by mass). The average particle size of the obtained fluorine-containing seed polymer (B) particles was 166nm.

[0131] Example 4 In a separable flask equipped with a thermometer, dropping funnel, reflux tubing, and stirrer, 1170 g of an aqueous dispersion of fluorine-containing polymer (A) adjusted to a solid content concentration of 43.5% by mass, and an aqueous solution of (c-2) 21.8 g, (c-1) 5.8 g, and 8.6 g of pure water were added. After stirring for 15 minutes, the mixture was heated and the internal temperature was raised to 80°C.

[0132] Here, as acrylic monomers, 180g of methyl methacrylate (MMA), 151g of n-butyl acrylate (n-BA), 3.4g of acrylic acid (AA), 0.4g of N-dodecyl mercaptan, 89g of pure water, 21.8g of (c-2), and 5.8g of (c-1) were mixed with 8.6g of pure water to create an aqueous solution, which was then pre-emulsified. To this emulsion, an aqueous solution of 0.9g of ammonium persulfate dissolved in 22g of pure water was added and placed in a dropping funnel. Polymerization was carried out by dropping the mixture into the separable flask over 3 hours. After that, the mixture was aged at 80°C for 1 hour. The reaction solution was cooled to 70°C, neutralized with 19g of saturated sodium bicarbonate solution, and then the pH was adjusted to 7-8 using a 28% aqueous ammonia solution. After that, it was cooled to room temperature to obtain an aqueous dispersion of fluorine-containing seed polymer (B) particles (solid content concentration 50% by mass). The average particle size of the obtained fluorine-containing seed polymer (B) particles was 156 nm.

[0133] Example 5 In a separable flask equipped with a thermometer, dropping funnel, reflux tubing, and stirrer, 1170 g of an aqueous dispersion of fluorine-containing polymer (A) adjusted to a solid content concentration of 43.5% by mass, and an aqueous solution of (c-2) 21.8 g, (c-1) 16.5 g, and 25 g of pure water were added. After stirring for 15 minutes, the mixture was heated and the internal temperature was raised to 80°C.

[0134] Here, as acrylic monomers, 180g of methyl methacrylate (MMA), 151g of n-butyl acrylate (n-BA), 3.4g of acrylic acid (AA), 0.4g of N-dodecyl mercaptan, 89g of pure water, 21.8g of (c-2), and 5.8g of (c-1) were mixed with 8.6g of pure water to create an aqueous solution, which was then pre-emulsified. To this emulsion, an aqueous solution of 0.9g of ammonium persulfate dissolved in 22g of pure water was added and placed in a dropping funnel. Polymerization was carried out by dropping the mixture into the separable flask over 3 hours. After that, the mixture was aged at 80°C for 1 hour. The reaction solution was cooled to 70°C, neutralized with 19g of saturated sodium bicarbonate solution, and then the pH was adjusted to 7-8 using a 28% aqueous ammonia solution. After that, it was cooled to room temperature to obtain an aqueous dispersion of fluorine-containing seed polymer (B) particles (solid content concentration 50% by mass). The average particle size of the obtained fluorine-containing seed polymer (B) particles was 151 nm.

[0135] Example 6 In a separable flask equipped with a thermometer, dropping funnel, reflux tubing, and stirrer, 1170 g of an aqueous dispersion of fluorine-containing polymer (A) adjusted to a solid content concentration of 43.5% by mass, and an aqueous solution of (c-2) 21.8 g, (c-1) 28 g, and 40.8 g of pure water were added. After stirring for 15 minutes, the mixture was heated and the internal temperature was raised to 80°C.

[0136] Here, as acrylic monomers, 180g of methyl methacrylate (MMA), 151g of n-butyl acrylate (n-BA), 3.4g of acrylic acid (AA), 1.9g of N-dodecyl mercaptan, 89g of pure water, 21.8g of (c-2), and 5.8g of (c-1) were mixed with 8.6g of pure water to create an aqueous solution, which was then pre-emulsified. To this emulsion, an aqueous solution of 0.9g of ammonium persulfate dissolved in 22g of pure water was added and placed in a dropping funnel. Polymerization was carried out by dropping the mixture into the separable flask over 3 hours. After that, the mixture was aged at 80°C for 1 hour. The reaction solution was cooled to 70°C, neutralized with 19g of saturated sodium bicarbonate solution, and then the pH was adjusted to 7-8 using a 28% aqueous ammonia solution. After that, it was cooled to room temperature to obtain an aqueous dispersion of fluorine-containing seed polymer (B) particles (solid content concentration 50% by mass). The average particle size of the obtained fluorine-containing seed polymer (B) particles was 160 nm.

[0137] Example 7 In a separable flask equipped with a thermometer, dropping funnel, reflux tubing, and stirrer, 936 g of an aqueous dispersion of a fluorine-containing polymer (A) adjusted to a solid content concentration of 43.5% by mass was added, along with an aqueous solution prepared by dissolving 15.8 g of Eleminol JS-20(c-4), a sodium alkylallyl sulfosuccinate, 20 g of RMA-450M(c-6), a methacrylic acid ester of polyethylene glycol monomethyl ether, and 1.8 g of Eleminol RS-3000(c-5), a sodium methacryloyloxypropylene sulfate, in 20 g of pure water. The mixture was then stirred for 15 minutes.

[0138] To this, 144 g of methyl methacrylate (MMA), 121 g of n-butyl acrylate (n-BA), 2.7 g of acrylic acid (AA), 0.3 g of N-dodecyl mercaptan, 80 g of pure water, and 2.3 g of (c-4) were added as acrylic monomers and mixed to pre-emulsify. This emulsion was mixed and placed in a dropping funnel, then introduced into the previously prepared separable flask and stirred at room temperature for 1 hour. Next, the temperature was raised to 75°C, and an aqueous solution of 0.3 g of ammonium persulfate dissolved in 22 g of pure water was placed in a dropping funnel. Polymerization was carried out dropwise from the dropping funnel over 3 hours, and then the mixture was aged at 80°C for 1 hour. The reaction solution was cooled to 70°C, neutralized with 19 g of saturated sodium bicarbonate solution, and the pH was adjusted to 7-8 using a 28% aqueous ammonia solution. After that, it was cooled to room temperature to obtain an aqueous dispersion of fluorine-containing seed polymer (B) particles (solid content concentration 50% by mass). The average particle size of the obtained fluorine-containing seed polymer (B) particles was 157 nm.

[0139] Example 8 50.00g of pure water, 2.60g of (c-2), and 2.00g of (c-1) were added to a 200ml stainless steel autoclave with a stirrer. Then, 14.25g of cyclohexyl vinyl ether (CHVE), 0.2g of acrylic acid, 8.45g of ethyl vinyl ether (EVE), 0.35g of potassium carbonate (K2CO3), 0.02g of sodium bisulfite (NaHSO3), and 0.08g of ammonium persulfate (initiator) were added. The autoclave was then cooled with ice and nitrogen gas was supplied at 3.5 kg / cm³. 2 The mixture was pressurized and degassed to a certain pressure. After repeating this pressurized degassing process twice, the mixture was degassed to 10 mmHg to remove dissolved oxygen. Then, 27.10 g of chlorotrifluoroethylene (CTFE) was added, and the reaction was carried out at 70°C for 8 hours to obtain an aqueous dispersion of a fluorine-containing polymer. After maturation at 80°C, the concentration was adjusted, and the reaction solution was cooled to room temperature to terminate the reaction. The pH was adjusted to 7-8 using a 28% ammonia aqueous solution to obtain an aqueous dispersion of resin particles (solid content concentration 50% by mass). The average particle size of the resin particles in the obtained aqueous dispersion was 121 nm.

[0140] Comparative Example 1 In a separable flask equipped with a thermometer, dropping funnel, reflux tubing, and stirrer, 1170 g of an aqueous dispersion of fluorine-containing polymer (A) adjusted to a solid content concentration of 43.5% by mass, and an aqueous solution of (c-2) 21.8 g, (c-1) 5.8 g, and 8.6 g of pure water were added. After stirring for 15 minutes, the mixture was heated and the internal temperature was raised to 80°C.

[0141] Here, 180g of methyl methacrylate (MMA), 151g of n-butyl acrylate (n-BA), 3.4g of acrylic acid (AA), 0.4g of N-dodecyl mercaptan, 89g of pure water, 21.8g of (c-2), and 5.8g of (c-1) were mixed with 8.6g of pure water to create an aqueous solution, which was then pre-emulsified. To this emulsion, an aqueous solution of 0.9g of ammonium persulfate dissolved in 22g of pure water was added and placed in a dropping funnel. Polymerization was carried out by dropping the mixture into the separable flask over 3 hours. After aging at 80°C, the reaction solution was cooled to room temperature to terminate the reaction. After neutralization with 19g of saturated sodium bicarbonate solution, the pH was adjusted to 7-8 using a 28% aqueous ammonia solution to obtain an aqueous dispersion of fluorine-containing seed polymer (B) particles (solid content concentration 50% by mass). The average particle size of the obtained fluorine-containing seed polymer (B) particles was 158nm.

[0142] Comparative Example 2 In a separable flask equipped with a thermometer, dropping funnel, reflux tubing, and stirrer, 936 g of an aqueous dispersion of fluorine-containing polymer (A), adjusted to a solid content concentration of 43.5% by mass, and an aqueous solution prepared by dissolving 15.8 g of (c-4), 20 g of (c-6), and 1.8 g of (c-5) in 20 g of pure water were added, and the mixture was stirred for 15 minutes.

[0143] To this, 144 g of methyl methacrylate (MMA), 121 g of n-butyl acrylate (n-BA), 2.7 g of acrylic acid (AA), 0.3 g of N-dodecyl mercaptan, 80 g of pure water, and 2.3 g of (c-4) were added as acrylic monomers and mixed to pre-emulsify. This emulsion was mixed and placed in a dropping funnel, then introduced into the previously prepared separable flask and stirred at room temperature for 1 hour. Next, the temperature was raised to 75°C, and an aqueous solution of 0.3 g of ammonium persulfate dissolved in 22 g of pure water was placed in a dropping funnel. Polymerization was carried out dropwise from the dropping funnel over 3 hours, and after aging at 80°C for 1 hour, the reaction solution was cooled to room temperature to complete the reaction. After neutralization with 19 g of saturated sodium bicarbonate solution, the pH was adjusted to 7-8 using a 28% aqueous ammonia solution to obtain an aqueous dispersion of fluorine-containing seed polymer (B) particles (solid content concentration 50% by mass). The average particle size of the obtained fluorine-containing seed polymer (B) particles was 161 nm.

[0144] Comparative Example 3 In a separable flask equipped with a thermometer, dropping funnel, reflux tubing, and stirrer, 936 g of an aqueous dispersion of fluorine-containing polymer (A) adjusted to a solid content concentration of 43.5% by mass was added, along with an aqueous solution of 17.4 g of (c-2) and 33 g of Adekarya soap ER-40(c-3), which is an oxirane polymerization adduct of {alkanol (C=10~14, branched type) and 1-(allyloxy)-2,3-epoxypropane}, mainly composed of α-[2-(allyloxy)1-({[alkyl(C=10~14)]oxy}methyl)ethyl]-ω-hydroxypoly(n=1~100)(oxyethylene), with an EO value of 40, and an aqueous solution of 22 g of pure water was added. After stirring for 15 minutes, the solution was heated and the internal temperature was raised to 80°C.

[0145] Here, 144 g of methyl methacrylate (MMA), 121 g of n-butyl acrylate (n-BA), 2.7 g of acrylic acid (AA), 0.3 g of N-dodecyl mercaptan, 80 g of pure water, 17.4 g of (c-2), and 5.8 g of (c-3) were dissolved in 5.7 g of pure water and mixed to create an aqueous solution which was then pre-emulsified. To this emulsion, an aqueous solution of 0.9 g of ammonium persulfate dissolved in 22 g of pure water was mixed and placed in a dropping funnel. Polymerization was carried out by dropping the mixture into the separable flask over 3 hours. After aging at 80°C, the reaction solution was cooled to room temperature to terminate the reaction. After neutralization with 19 g of saturated sodium bicarbonate solution, the pH was adjusted to 7-8 using a 28% aqueous ammonia solution to obtain an aqueous dispersion of fluorine-containing seed polymer (B) particles (solid content concentration 50% by mass). The average particle size of the obtained fluorine-containing seed polymer (B) particles was 159 nm.

[0146] (Evaluation method) (Zeta potential) The aqueous dispersion was diluted 100-fold with pure water. The zeta potential was measured using a zeta potential meter ELSZ-2000 (manufactured by Otsuka Electronics).

[0147] (mechanical stability) The aqueous dispersion was diluted with water to a concentration of 50%. 100g of the emulsion was placed in a metal container and heated to 50°C using a water bath while being stirred at 2000 rpm using a homodisperser. The time taken from the start of stirring until the rotation speed increased by more than 50% was measured. The evaluation was conducted based on the following criteria. ◎: 25 minutes or more 〇: 15 minutes or more but less than 25 minutes ×: Less than 15 minutes

[0148] (Amount of aggregated material) The aqueous dispersion after polymerization was filtered through a 400-mesh filter, and the presence or absence of aggregates on the mesh was visually assessed. A × indicated the presence of aggregates, while a ○ indicated no aggregates.

[0149] (Storage stability) Aqueous dispersions were stored at 50°C for 10 weeks. The solid content concentration, viscosity, pH, and MFT (minimum film-forming temperature) of the aqueous dispersions were measured. A sample was marked with a circle (○) if it met all of the following criteria: solid content of 50-52%, pH of 6-8, viscosity of 10-45 mPa·s, and MFT of 10-18°C. A sample was marked with a cross (×) if even one of these criteria was not met. The above MFT was measured using a thermal gradient testing apparatus (manufactured by Nichiri Shoji Co., Ltd.). An aqueous dispersion was applied to a wet film thickness of 90 μm, dried under the following conditions, and the highest temperature at which no cracks appeared in the coating film was visually recorded. Set temperature gradient: 5°C to 25°C

[0150] (water resistance) Several grams of aqueous dispersion were dropped onto a glass plate and applied using a 6 mil applicator. After drying at 60°C for 15 minutes, the plate was immersed in room temperature water for 24 hours. The degree of whitening upon removal was visually assessed, with × indicating whitening present and ○ indicating no whitening.

[0151] (Weather resistant QUV) 100 g of an aqueous dispersion, adjusted with water to a solids content of 50%, was mixed with 5 g of diethyl adipate and stirred for 30 minutes. Then, 0.1 g of BYK028 (manufactured by Bic Chemie) and 0.3 g of Adekanol UH420 (manufactured by ADEKA) were added and stirred for another 30 minutes. Several g of the resulting coating was dropped onto an aluminum plate and coated with a #30 bar coater. The 60°C gloss, L*, a*, and b* values ​​of the resulting test pieces were measured using a gloss meter and colorimeter. The test pieces were then tested for 1000 hours using an accelerated weathering tester (QUV, manufactured by Q-Lab). The test conditions were as follows: The 60° gloss, L*, a*, and b* values ​​of the test pieces were measured after the test. The gloss retention rate and ΔE((ΔL*)) were measured after the test. 2 +(Δa*) 2 +(Δb*) 2 ] 1 / 2 Weather resistance was evaluated based on the values ​​of ). A "○" was given if the gloss retention rate was 80% or higher, ΔE was 1.0 or lower, and there were no abnormalities in appearance; a "×" was given if even one of these conditions was not met. Test conditions 1 cycle = 8-hour cycle (i) Irradiation (black panel temperature: 60℃, illuminance: 0.63W / m²) 2 ):4 hours (ii) Darkness and condensation (tank temperature: 50°C): 4 hours

[0152] (Average particle size) The average particle size of the aqueous dispersion was measured using a Nanotrac Wave particle size analyzer (manufactured by Otsuka Electronics).

[0153] [Table 1]

[0154] [Table 2]

[0155] [Table 3]

[0156] [Table 4]

[0157] The results in Tables 1-4 clearly demonstrate that the aqueous dispersions of this disclosure possess excellent performance. From the examples, it was confirmed that aqueous dispersions having units (b) with acidic and basic functional groups, and with an absolute value of zeta potential of 52 mV or higher, exhibit high mechanical stability, low aggregate content, and high storage stability, water resistance, and weather resistance. [Industrial applicability]

[0158] The aqueous dispersion of this disclosure exhibits excellent mechanical stability and other effects, making it suitable for use in the field of coatings.

Claims

1. A step (I) of preparing fluorine-containing polymer (A) particles having a unit (a) based on a fluoroolefin, Polymerization step (II) involves polymerizing the fluorine-containing polymer (A) particles, a monomer comprising at least one unit (b) selected from the group consisting of (meth)acrylic acid, (meth)acrylic acid salts, and (meth)acrylic acid esters, and a constituent unit (c) derived from a monomer having an oxyalkylene group in an aqueous medium. Step (III) of neutralizing the aqueous dispersion obtained by the polymerization step (II) It has, The aqueous dispersion obtained by the polymerization step (II) is A unit (a) based on fluoroolefins, and, The resin particles contain at least one unit (b) selected from the group consisting of (meth)acrylic acid, (meth)acrylic acid salts, and (meth)acrylic acid esters. The resin particles are a fluorine seed polymer comprising the fluorine-containing polymer (A) particles and a monomer containing at least one unit (b) selected from the group consisting of (meth)acrylic acid, (meth)acrylic acid salts, and (meth)acrylic acid esters. The resin particles are copolymerized in which a constituent unit (c) derived from a monomer having an oxyalkylene group is copolymerized with the unit (b). In step (III), the neutralization reaction is carried out at 50-70°C. A method for producing an aqueous dispersion, characterized in that the obtained aqueous dispersion contains the resin particles and has an absolute value of 60.7 mV or more in zeta potential.

2. A unit (a) based on a fluoroolefin, and (b) at least one unit selected from the group consisting of (meth)acrylic acid, (meth)acrylic acid salts and (meth)acrylic acid esters, and It contains a constituent unit (c) derived from a monomer having an oxyalkylene group, The process includes a step (III) of neutralizing an aqueous dispersion containing resin particles in which a polymer based on the aforementioned unit (a) and the aforementioned unit (b) exists as a copolymer, and a constituent unit (c) derived from a monomer having an oxyalkylene group is copolymerized with the aforementioned unit (b), In the above step (III), the neutralization reaction is carried out at 50 to 70°C. A method for producing an aqueous dispersion, characterized in that the obtained aqueous dispersion contains the resin particles and has an absolute value of 57.0 mV or more in zeta potential.

3. The oxyalkylene group is defined by the following formula 【Chemistry 1】 A method for producing an aqueous dispersion according to claim 1 or 2, wherein the (poly)alkylene oxide chain is represented by the formula (wherein R 10 is an alkylene group having 4 or fewer carbon atoms, and n is 1 to 39).

4. The unit (c) is at least a part of the following general formula (2) CH 2 =CHCH 2 -O-R 2 (2) A method for producing an aqueous dispersion according to claim 1 or 2, wherein the nonionic surfactant (c-1) is represented by the formula (wherein R2 is a hydrocarbon group having a nonionic hydrophilic group).

5. The nonionic surfactant (c-1) is the following formula (c1): 【Chemistry 2】 A method for producing an aqueous dispersion according to claim 4, comprising a compound (c-1-1) represented by (wherein R 1' is a linear or branched hydrocarbon chain which may contain an oxygen atom, a phenyl group, or a phenylene group; n is an integer from 1 to 60).

6. A unit (a) based on fluoroolefins, and, The resin particles contain at least one unit (b) selected from the group consisting of (meth)acrylic acid, (meth)acrylic acid salts, and (meth)acrylic acid esters. The resin particles are a fluorine seed polymer comprising fluorine-containing polymer (A) particles having a unit (a) based on fluoroolefin, and a monomer containing at least one unit (b) selected from the group consisting of (meth)acrylic acid, (meth)acrylic acid salts, and (meth)acrylic acid esters. The resin particles are copolymerized in which a constituent unit (c) derived from a monomer having an oxyalkylene group is copolymerized with the unit (b). An aqueous dispersion characterized by having an absolute value of 60.7 mV or higher for its zeta potential.

7. A unit (a) based on a fluoroolefin, and An aqueous dispersion characterized by comprising at least one unit (b) selected from the group consisting of (meth)acrylic acid, salts of (meth)acrylic acid, and (meth)acrylic acid esters, wherein a polymer based on unit (a) and unit (b) exists as a copolymer, and the dispersion contains resin particles in which a constituent unit (c) derived from a monomer having an oxyalkylene group is copolymerized with unit (b), and the absolute value of the zeta potential is 57.0 mV or higher.

8. The aqueous dispersion according to claim 6 or 7, wherein unit (b) comprises a functional group in which at least some of the -COOH groups are neutralized with a base.

9. The aqueous dispersion according to claim 6 or 7, wherein the fluoroolefin comprises at least one fluoroolefin unit selected from the group consisting of vinyl fluoride, vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene, and chlorotrifluoroethylene.

10. The oxyalkylene group is defined by the following formula 【Transformation 3】 The aqueous dispersion according to claim 6 or 7, wherein the (poly)alkylene oxide chain is represented by the formula (wherein R 10 is an alkylene group having 4 or fewer carbon atoms, and n is 1 to 39).

11. The unit (c) is at least partially derived from the following general formula (2) CH ２ =CHCH ２ -O-R ２ (2) (In the formula, R ２ The aqueous dispersion according to claim 6 or 7, wherein is a hydrocarbon group having a nonionic hydrophilic group. (c-1) is a nonionic surfactant represented by ).

12. The nonionic surfactant (c-1) is the following formula (c1): 【Chemistry 4】 The aqueous dispersion according to claim 11, comprising a compound (c-1-1) represented by (wherein R 1' is a linear or branched hydrocarbon chain which may contain an oxygen atom, a phenyl group or a phenylene group; n is an integer from 1 to 60).

13. The unit (c) is at least partly derived from the following general formula (3): HH ２ =HHH ２ -O-R ３ -X (3) (wherein R ３ is a hydrocarbon chain which may have an oxygen atom and / or a nitrogen atom; X is SO ３ Y (Y is NH ４ or an alkali metal).) The aqueous dispersion according to claim 6 or 7, which is an anionic surfactant (c-2) represented by the formula.)

14. The unit (c) is partly derived from the following general formula (2) CH ２ =CHCH ２ -O-R ２ (2) (In the formula, R ２ is a hydrocarbon group having a nonionic hydrophilic group. ) is a nonionic surfactant (c-1) represented by ), and Part of it is the following general formula (3): HH ２ =HHH ２ -O-R ３ -X (3) (In the formula, R ３ X is a hydrocarbon chain which may have oxygen atoms and / or nitrogen atoms; X is SO ３ Y (Y is NH) ４ The aqueous dispersion according to claim 6 or 7, which is an anionic surfactant (c-2) represented by (or an alkali metal).

15. The aqueous dispersion according to claim 6 or 7, wherein the result of the mechanical stability test is 15 minutes or more.

16. Unit (b) comprises a functional group in which at least some of the -COOH groups are neutralized with a base, Fluoroolefins include at least one fluoroolefin unit selected from the group consisting of vinyl fluoride, vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene, and chlorotrifluoroethylene. The aqueous dispersion according to claim 14, wherein the absolute value of the zeta potential is 60.7 mV or more.

17. A water-based paint characterized by comprising the aqueous dispersion described in claim 6 or 7.

18. A water-based paint characterized by comprising the aqueous dispersion described in claim 6 or 7 and an acrylic resin.

19. A coating film characterized by being obtained from the aqueous dispersion described in claim 6 or 7.

20. A coated article characterized by comprising the coating film described in claim 19.

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