JP5920975B2 - Resin for pigment dispersion - Google Patents

Description

  The present invention relates to a pigment dispersing resin suitable for an aqueous coating material, an aqueous pigment dispersion containing the pigment dispersing resin, and an aqueous coating composition containing the pigment dispersing resin.

  In recent years, from the viewpoint of protecting the global environment, paints having a low volatile organic matter content (VOC) are required, and switching from solvent-based paints to water-based paints is being promoted.

Here, the problems associated with the aqueousization of paints are that the pigments used in paints are generally hydrophobic and difficult to wet with water, and the pigment dispersion resins conventionally used in solvent-type colored paints are For example, the solubility in water is low and the dispersion stability in an aqueous medium is poor. Therefore, in designing the pigment dispersion resin in the water-based paint, it is important to satisfy both the wettability of the pigment and the dispersion stability of the pigment dispersion resin in the aqueous medium.

  With regard to the wettability of the pigment, it is said that it is advantageous that the resin for dispersing the pigment has a low viscosity and a low molecular weight. It is said that it is advantageous to have good solubility in the phase (aqueous medium). In addition, regarding the wettability of the pigment dispersion resin to the pigment surface and the adsorption to the pigment due to the interaction between the hydrophobic part of the pigment surface and the hydrophobic part of the pigment dispersion resin, the wettability of the pigment and the dispersion of the pigment dispersion resin Both stability is considered to be involved.

From the above viewpoint, development of pigment dispersion resins and auxiliaries for water-based paints or water-based inks has been carried out. For example, in Patent Document 1, a monomer mixture containing an acidic functional group-containing polymerizable unsaturated monomer such as (meth) acrylic acid as part of the monomer component is polymerized as a pigment dispersion resin. It has been proposed to use a linear anionic polymer having an acidic functional group.
Patent Document 2, Patent Document 3 and Patent Document 4 disclose a graft copolymer obtained by copolymerizing a carboxyl group-containing macromonomer as a pigment dispersion resin.
Further, Patent Document 5, Patent Document 6 and Patent Document 7 disclose the use of a nonionic surfactant having a polyoxyalkylene chain as a pigment dispersant.
Patent Document 8 and Patent Document 9 are copolymers having a polymerizable unsaturated monomer containing an ionic functional group and a nonionic polymerizable unsaturated monomer having a polyoxyalkylene chain as a copolymerization component. A pigment dispersing resin is disclosed.

JP 50-154328 A JP-A-1-182304 JP 7-316240 A Japanese National Patent Publication No. 10-502097 JP-A-9-255728 Japanese Patent Laid-Open No. 9-267034 Japanese Patent Publication No.8-19201 WO02 / 31010 Publication JP 2003-12744 A

  However, the pigment dispersion resin disclosed in Patent Document 1 is a dispersion-stabilizing pigment dispersion because the linear anionic polymer having an acidic functional group has high solubility in an aqueous medium. In addition, there is a problem that the dispersion formed using the dispersion is extremely high in viscosity and difficult to handle.

  In addition, the pigment dispersion resins disclosed in Patent Document 2, Patent Document 3 and Patent Document 4 are such that the graft copolymer obtained by copolymerizing a carboxyl group-containing macromonomer has a hydrophobic polymer trunk portion. And the branch part is hydrophilic, it is excellent in stabilizing the dispersion of the pigment. However, the pigment dispersion formed using the graft copolymer has a high viscosity and will be used in the future in terms of cost and VOC. From the viewpoint of reduction, since the pigment dispersion having a higher pigment concentration is required, the above graft copolymer is never satisfactory.

  Further, the nonionic surfactants disclosed in Patent Document 5, Patent Document 6 and Patent Document 7 can exist stably in the aqueous pigment dispersion, but the adsorptivity to the pigment is insufficient. In particular, the let-down stability is poor and the finished appearance of the coating film tends to be inferior.

  In addition, by using the pigment dispersing resin disclosed in Patent Document 8 and Patent Document 9, an aqueous pigment having a low viscosity, excellent color developability and excellent finished appearance of the coating film even at a high pigment concentration. A dispersion can be obtained. At present, however, top coatings for automotive coatings not only have high durability, acid resistance, car wash scuff resistance, chipping resistance and other coating performance, but also more vividness, transparency and color development than ever before. The finished appearance of the coating film is required. In that respect, the above-mentioned resin for dispersing pigments may not have sufficient color developability and sharpness of the coating film obtained, and particularly when black pigments such as carbon black are dispersed, jet blackness (particularly pigments among color developability) In some cases, it is lacking in blackness when it is a black pigment.

  The present invention has been made in view of these points, and an object of the present invention is to obtain a pigment-dispersing resin excellent in the finished appearance of a coating film such as color developability, jetness, and sharpness. Another object of the present invention is to obtain a water-based coating composition excellent in the finished appearance of a coating film such as color developability, jetness blackness, and sharpness using the pigment dispersing resin.

  As a result of intensive studies to achieve the above object, the present inventors have found that a polymerizable unsaturated monomer having a specific cationic functional group and a copolymer of the other polymerizable unsaturated monomer are aqueous. The present invention has been completed by finding that it is extremely suitable as a pigment dispersion resin in paints.

That is, the present invention provides the following pigment dispersion resin and aqueous coating composition.
Item 1.
A resin for pigment dispersion, which is a copolymer of (a) a polymerizable unsaturated monomer having a cationic functional group represented by the general formula (1), and (b) another polymerizable unsaturated monomer.
General formula (1)

[Wherein, X represents a group represented by the following general formula (2) ~ (4), R 1 represents a hydrogen atom or a methyl group, ^{R 2} represents a methyl group]
General formula (2)

[Wherein Y represents an alkylene group or a polyoxyalkylene group having one or more repeating units. In addition, p represents an integer of 1 or more when Y is an alkylene group, and p represents an integer of 0 or more when Y is a polyoxyalkylene group having 1 or more repeating units. ]
General formula (3)

[Wherein q represents an integer of 0 or more]
General formula (4)

[Wherein Z represents a linear or branched alkyl chain or a polyoxyalkylene group having one or more repeating units. ]
Item 2.
Item 2. The pigment dispersion resin according to Item 1, wherein the other polymerizable unsaturated monomer (b) contains a polymerizable unsaturated monomer having a (b1) polyoxyalkylene chain represented by the following general formula (5).

［式中、Ｒ^３は水素原子またはメチル基を表し、Ｒ^４は水素原子又は分岐してもよい炭素数１〜４のアルキル基を表し、Ｒ^５は分岐してもよい炭素数２〜４のアルキレン基を表し、ｍは３〜１５０の整数を表し、ｍ個のオキシアルキレン単位（Ｒ^５Ｏ）はそれぞれ互いに同じであっても又は互いに異なっていてもよい］
項３．
その他の重合性不飽和モノマー（ｂ）が（ｂ２）ポリオキシアルキレン鎖を有さない水酸基含有重合性不飽和モノマーを含有する上記項１または２に記載の顔料分散用樹脂。
項４.
一般式（１）で示されるカチオン性官能基を含有する重合性不飽和モノマー（ａ）のＸが、上記一般式（２）においてｐが１または２である上記項１ないし３のいずれか１項に記載の顔料分散用樹脂。
項５.
共重合体が５００〜１００，０００の範囲内の重量平均分子量を有する上記項１ないし４のいずれか１項に記載の顔料分散用樹脂。
項６.
上記項１ないし５のいずれか１項に記載の顔料分散用樹脂、顔料及び水性媒体を含有する水性顔料分散体。
項７.
上記項６に記載の水性顔料分散体を含有する水性塗料組成物。
項８.
上記項７に記載の水性塗料組成物を用いて塗装された物品。

[Wherein, R ³ represents a hydrogen atom or a methyl group, R ⁴ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms which may be branched, and R ⁵ represents an alkyl group having 2 to 4 carbon atoms which may be branched. M represents an integer of 3 to 150, and the m oxyalkylene units (R ⁵ O) may be the same as or different from each other.]
Item 3.
Item 3. The pigment dispersion resin according to Item 1 or 2, wherein the other polymerizable unsaturated monomer (b) contains (b2) a hydroxyl group-containing polymerizable unsaturated monomer having no polyoxyalkylene chain.
Item 4.
Any one of Items 1 to 3 , wherein X of the polymerizable unsaturated monomer (a) containing a cationic functional group represented by the general formula (1) is 1 or 2 in the general formula (2). The pigment dispersing resin described in the item.
Item 5 .
Item 5. The pigment dispersion resin according to any one of Items 1 to 4 , wherein the copolymer has a weight average molecular weight in the range of 500 to 100,000.
Item 6 .
6. An aqueous pigment dispersion containing the pigment dispersion resin according to any one of items 1 to 5 , a pigment, and an aqueous medium.
Item 7 .
7. An aqueous coating composition containing the aqueous pigment dispersion according to item 6 .
Item 8 .
Article coated with the water-based coating composition according to Item 7 .

  According to the pigment dispersion resin of the present invention, the problems in the prior art are solved.

Hereinafter, the pigment-dispersing resin and the aqueous coating composition of the present invention will be described in more detail.
Pigment-dispersing resin The pigment-dispersing resin provided by the present invention includes a polymerizable unsaturated monomer (a) having a cationic functional group represented by the following general formula (1), and other polymerizable unsaturated monomers It is a copolymer of (b).

Polymerizable unsaturated monomer (a) having a cationic functional group represented by the general formula (1)
The polymerizable unsaturated monomer (a) having a cationic functional group represented by the general formula (1) (sometimes abbreviated as “monomer (a)”) has a relatively long chain in the pigment dispersion resin of the present invention. It is a monomer component for introducing a secondary or tertiary amino group.

Here, the polymerizable unsaturated monomer (a) having a cationic functional group represented by the general formula (1) is represented by the general formula (1).
General formula (1)

[Wherein, X represents a linear or branched alkylene group having a main chain of 6 or more carbon atoms, or a group represented by the following general formulas (2) to (4), wherein R ¹ and R ² are Represents a hydrogen atom or a methyl group]
General formula (2)

[Wherein Y represents an alkylene group or a polyoxyalkylene group having one or more repeating units. In addition, p represents an integer of 1 or more when Y is an alkylene group, and p represents an integer of 0 or more when Y is a polyoxyalkylene group having 1 or more repeating units. ]
General formula (3)

[Wherein q represents an integer of 0 or more]
General formula (4)

[Wherein Z represents an alkylene chain which may be linear or branched, or a polyoxyalkylene group having one or more repeating units. ]
X in the general formula (1) represents an alkylene group whose main chain may be linear or branched having 6 or more carbon atoms, or a group represented by the above general formulas (2) to (4). Of the cases where X is an alkyl group having 6 or more carbon atoms, which may be linear or branched, it is straightforward from the viewpoint of obtaining a water-based coating composition excellent in the finished appearance of the coating film such as color developability, jet blackness, and sharpness. The chain is preferably a hexylene group, a heptylene group or an octylene group.

  Of the groups represented by the general formulas (2) to (4), the group represented by the general formula (2) is preferable from the viewpoint of ease of synthesis.

  In the case of the general formula (2), Y is preferably a methylene group, an oxyethylene group and / or an oxypropylene group from the viewpoint of easy availability of materials.

  P in the general formula (2) represents an integer of 1 or more when Y is an alkylene group, and represents an integer of 0 or more when Y is a polyoxyalkylene group having 1 or more repeating units. When Y is a polyoxyalkylene group having a repeating unit of 1 or more, p is preferably 0 or 1 from the viewpoint of obtaining a water-based coating composition excellent in the finished appearance of the coating film such as color developability, jetness, and sharpness. It is preferable.

  Q in the general formula (3) represents an integer of 0 or more, but q is 0 or 1 from the viewpoint of obtaining a water-based coating composition excellent in the finished appearance of the coating film such as color developability, jet blackness, and sharpness. It is preferable that

  Z in the general formula (4) represents an alkyl chain which may be linear or branched or a polyoxyalkylene group having one or more repeating units, and has excellent finished appearance of the coating film such as color developability, jetness and vividness. From the viewpoint of obtaining an aqueous coating composition, it is more preferably a polyoxyalkylene having one or more repeating units. As the polyoxyalkylene group, an oxyethylene group or an oxypropylene group having a repeating unit of 1 is preferable from the viewpoint of easy availability of materials.

  The polymerizable unsaturated monomer (a) having a cationic functional group represented by the general formula (1) can be used alone or in combination of two or more.

  In addition, the polymerizable unsaturated monomer (a) having a cationic functional group represented by the general formula (1) is an aqueous coating composition excellent in the finished appearance of the coating film such as color developability, jet blackness, and sharpness. From the viewpoint of obtaining, it is preferable to have an oxyethylene chain.

Method for preparing polymerizable unsaturated monomer (a) having cationic functional group represented by general formula (1)
Preparation of monomer (a) wherein X is an alkylene group having a main chain of 6 or more carbon atoms and may be linear or branched X may be linear or branched having a main chain of 6 or more carbon atoms The monomer (a) which is an alkylene group (sometimes referred to as “monomer (a-1)”) is a compound having a (meth) acryloyl group and an amine compound having a primary hydroxyl group at the terminal and having an alkyl chain. Can be obtained by reacting.

  Examples of the compound having the (meth) acryloyl group include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and butyl (meth) acrylate. Of these, methyl (meth) acrylate is preferred from the viewpoint of reactivity.

  The amine compound having a primary hydroxyl group at the terminal and having an alkyl chain has a carbon number of 9 or more and a linear alkyl group, or the main chain has a carbon number even if it is branched. As long as it has 9 or more carbons to which an amino group is bonded and an alkyl group that is not branched from the adjacent carbon, it can be used without particular limitation. Examples of the amine compound having a primary hydroxyl group at the terminal and having an alkyl chain include N-methylamino-nonanol, N, N-dimethylamino-nonanol, N-methylamino-decanol, N, N-dimethylamino. -Decanol, N-methylamino-dodecanol, N, N-dimethylamino-dodecanol, N-methylamino-tetradecanol, N, N-dimethylamino-tetradecanol, N-methylamino-pentadecanol, N, N-dimethylamino-pentadecanol, N-methylamino-hexadecanol, N, N-dimethylamino-hexadecanol, N-methylamino-octadecanol, N, N-dimethylamino-octadecanol, etc. Can be mentioned.

Among these, N, N-dimethylamino-9-nonyl alcohol and N, N-dimethylamino-10-decyl alcohol are preferable from the viewpoint of low viscosity at room temperature and easy handling.
The reaction between the compound having the (meth) acryloyl group and the amine compound having a primary hydroxyl group at the terminal and having an alkyl chain can be carried out by a method known per se, for example, by transesterification. be able to. The amount of the compound having a (meth) acryloyl group and the amine compound having a primary hydroxyl group at the terminal and having an alkyl chain is such that the (meth) acryloyl group is used with respect to 1 equivalent of the hydroxyl group in the amine compound. The compound is preferably adjusted so as to be 0.1 to 10 equivalents, more preferably 0.5 to 8 equivalents, and particularly preferably 1 to 5 equivalents. When the amount of the compound having a (meth) acryloyl group is less than 0.1 equivalent, the yield of the polymerizable unsaturated monomer (a) having a cationic functional group is low, whereas when the amount exceeds 10 equivalents, ) A compound having an acryloyl group may remain, and the storage stability of the resulting polymer solution, pigment dispersion resin, aqueous pigment dispersion and aqueous coating composition may be lowered.

Preparation of monomer (a) wherein X is a group represented by general formula (2) Monomer (a) wherein X is a group represented by general formula (2) (sometimes referred to as “monomer (a-2)”) ) Can be obtained by reacting a compound having a (meth) acryloyl group and an isocyanate group (hereinafter sometimes abbreviated as “unsaturated isocyanate compound”) with an amine compound having a primary hydroxyl group at the terminal. it can.

Examples of the unsaturated isocyanate compound include 2-acryloyloxyethyl isocyanate, 3-acryloyloxypropyl isocyanate, 4-acryloyloxybutyl isocyanate, 6-acryloyloxyhexyl isocyanate, 8-acryloyloxyoctyl isocyanate, 10-acryloyloxydecyl. Isocyanate,
2- (2-isocyanatoethoxy) ethyl acrylate,
2- [2- (2-isocyanatoethoxy) ethoxy] ethyl acrylate,
2- {2- [2- (2-isocyanatoethoxy) ethoxy] ethoxy} ethyl acrylate,
2- (2-isocyanatopropoxy) ethyl acrylate,
Acrylic acid derivatives such as 2- [2- (2-isocyanatopropoxy) propoxy] ethyl acrylate;
2-methacryloyloxyethyl isocyanate, 3-methacryloyloxypropyl isocyanate, 4-methacryloyloxybutyl isocyanate, 6-methacryloyloxyhexyl isocyanate, 8-methacryloyloxyoctyl isocyanate, 10-methacryloyloxydecyl isocyanate,
2- (2-isocyanatoethoxy) ethyl methacrylate,
2- [2- (2-isocyanatoethoxy) ethoxy] ethyl methacrylate,
2- {2- [2- (2-isocyanatoethoxy) ethoxy] ethoxy} ethyl methacrylate
2- (2-isocyanatopropoxy) ethyl methacrylate,
Examples include methacrylic acid derivatives such as 2- [2- (2-isocyanatopropoxy) propoxy] ethyl methacrylate, and these can be used alone or in admixture of two or more.

  In addition, as a commercial product of 2-acryloyloxyethyl isocyanate, “Karenz AOI” (trade name, manufactured by Showa Denko), and as a commercial product of 2-methacryloyloxyethyl isocyanate, “Karenz MOI” (trade name, Showa Denko) As a commercially available product of 2- (2-isocyanatoethoxy) ethyl methacrylate, “Karenz MOI-EG” (trade name, manufactured by Showa Denko KK) can be mentioned.

  Among these unsaturated isocyanate compounds, 2-acryloyloxyethyl isocyanate, 2-methacryloyloxyethyl isocyanate, 4-methacryloyloxybutyl isocyanate, and methacrylic acid 2 from the viewpoint of reactivity with amine compounds having a primary hydroxyl group at the terminal. -(2-Isocyanatoethoxy) ethyl and the like are preferable.

  Examples of the amine compound having a primary hydroxyl group at the terminal include an amine compound having a primary hydroxyl group at the terminal and an alkyl chain, and an amine compound having a primary hydroxyl group at the terminal and an ethylene oxide chain. It is done.

  Examples of the amine compound having a primary hydroxyl group at the terminal and having an alkyl chain include N, N-dimethylaminoethanol when p is 0 in the monomer (a) used in the present invention.

  Examples of the amine compound having a primary hydroxyl group at the terminal and having an ethylene oxide chain include N-methylaminoethoxyethanol, N, N-dimethylaminoethoxyethanol, N-methylaminoethoxyethoxyethanol, and N, N-dimethyl. Amino ethoxy ethoxy ethanol etc. can be mentioned, These can be used individually or in mixture of 2 or more types.

  Of these, N, N-dimethylaminoethoxyethanol (2- [2- (dimethylamino) ethoxy] ethanol), N, N-dimethylaminoethoxyethoxyethanol (2- [2- [2 -(Dimethylamino) ethoxy] ethoxy] ethanol) is preferred.

  In the case where the monomer (a) used in the present invention is a group represented by the above general formula (2), when the unsaturated isocyanate compound in which Y is an alkylene group is selected, color developability and jetness From the viewpoint of obtaining a water-based coating composition excellent in the finished appearance of the coating film such as sharpness, an amine compound having a primary hydroxyl group at the terminal where p is 1 or more and having an ethylene oxide chain is selected.

  The reaction of the unsaturated isocyanate compound with an amine compound having a primary hydroxyl group at the terminal is, for example, a terminal containing a catalyst such as di-n-butyltin (IV) dilaurate and a polymerization inhibitor such as p-methoxyphenol. This can be carried out by adding an unsaturated isocyanate compound to a solution of an amine compound having a primary hydroxyl group at room temperature or with stirring.

The amount of the unsaturated isocyanate compound and the amine compound having a primary hydroxyl group at the terminal is preferably 0.5 to 2 for the isocyanate group in the unsaturated isocyanate compound with respect to 1 equivalent of the hydroxyl group in the amine compound. It is adjusted to 0.0 equivalent, more preferably 0.7 to 1.5 equivalent, and particularly preferably 0.8 to 1.2 equivalent. When the amount of the unsaturated isocyanate compound used is less than 0.5 equivalent, the yield of the polymerizable unsaturated monomer having a cationic functional group is low and the color developability is poor. On the other hand, when the amount exceeds 2.0 equivalents, unreacted unsaturated The isocyanate compound may remain, and the storage stability of the resulting polymer solution, pigment dispersion resin, aqueous pigment dispersion, and aqueous coating composition may be reduced.

Preparation of monomer (a) wherein X is a group represented by general formula (3) Monomer (a) wherein X is a group represented by general formula (3) (sometimes referred to as “monomer (a-3)”) ) Can be obtained by reacting a compound having a (meth) acryloyl group with an amine compound having a primary hydroxyl group at the terminal and having an ethylene oxide chain.

  As a compound which has the said (meth) acryloyl group, the compound enumerated in the said monomer (a-1) can be used, for example. Of these, methyl (meth) acrylate is preferred from the viewpoint of reactivity.

  As the amine compound having a primary hydroxyl group at the terminal and having an ethylene oxide chain, for example, the compounds listed in the monomer (a-2) can be used. Of these, N, N-dimethylaminoethoxyethanol (2- [2- (dimethylamino) ethoxy] ethanol), N, N-dimethylaminoethoxyethoxyethanol (2- [2- [2 -(Dimethylamino) ethoxy] ethoxy] ethanol) is preferred.

  The reaction between the compound having the (meth) acryloyl group and the amine compound having a primary hydroxyl group at the end and having an ethylene oxide chain can be carried out by a method known per se, for example, by transesterification. be able to.

  The amount of the compound having a (meth) acryloyl group and the amine compound having a primary hydroxyl group at the terminal and having an ethylene oxide chain is a compound having a (meth) acryloyl group with respect to 1 equivalent of the hydroxyl group in the amine compound. Is preferably adjusted to 0.1 to 10 equivalents, more preferably 0.5 to 8 equivalents, and particularly preferably 1 to 5 equivalents. When the amount of the compound having a (meth) acryloyl group is less than 0.1 equivalent, the yield of the polymerizable unsaturated monomer having a cationic functional group is small. On the other hand, when the amount exceeds 10 equivalents, an unreacted (meth) acryloyl group is removed. In some cases, the storage stability of the resulting polymer solution, pigment dispersion resin, aqueous pigment dispersion, and aqueous coating composition may be reduced.

Preparation of Monomer (a) wherein X is a Group Represented by General Formula (4) Monomer (a) wherein X is a group represented by General Formula (4) (sometimes referred to as “monomer (a-4)”) ) Can be obtained, for example, by reacting hydroxyethyl (meth) acrylate, isophorone diisocyanate and an amine compound having a primary hydroxyl group at the terminal.

  In addition, since the monomer (a-4) may be a monomer in which either isocyanate group of isophorone diisocyanate has a hydroxyethyl (meth) acrylate and an amine compound having a primary hydroxyl group at the terminal reacted. General formula (4) is written separately from general formulas (4) -I and (4) -II.

Examples of the amine compound having a primary hydroxyl group at the terminal include an amine compound having a primary hydroxyl group at the terminal and having an ethylene oxide chain, and an amine compound having a primary hydroxyl group at the terminal and having an alkyl chain. . As the amine compound having a primary hydroxyl group at the terminal and having an ethylene oxide chain, for example, the compounds listed in the monomer (a-2) can be used. The amine compound having a primary hydroxyl group at the terminal and having an alkyl chain may be an amine compound having a primary hydroxyl group at the terminal and having a linear or branched alkyl chain having 1 or more carbon atoms. Can be used without limitation. For example, in addition to the compounds listed in the monomer (a-1), N-methylaminomethanol, N-methylaminoethanol, N-methylaminopropanol (3-methylamino-1-propanol, 1-methylamino-2 -Propanol), N-methylaminobutanol (4-methylamino-1-butanol, 2-methylamino-isobutyl alcohol, etc.), N-methylaminopentanol (5-methylamino-1-pentanol, 4-methylamino) -2-methyl-1-butanol), N-methylaminohexanol (6-methylamino-1-hexanol, 5-methylamino-3-methyl-1-pentanol, 4-methylamino-2,2-dimethyl) -1-butanol, etc.), N-methylaminoheptanol (7-methylamino-1- Putanoru, 5-methyl-3,3-dimethyl-1-pentanol, etc.), N- methylamino-octanol (8-methyl-amino-1-octanol, 6-methyl-2-ethyl-1-hexanol, etc.)
N, N-dimethylaminomethanol, N, N-dimethylaminoethanol, N, N-dimethylaminopropanol (3-dimethylamino-1-propanol, 1-dimethylamino-2-propanol), N, N-dimethylaminobutanol (4-dimethylamino-1-butanol, 2-dimethylamino-isobutyl alcohol, etc.), N, N-dimethylaminopentanol (5-dimethylamino-1-pentanol, 4-dimethylamino-2-methyl-1- Butanol, etc.), N, N-dimethylaminohexanol (6-dimethylamino-1-hexanol, 5-dimethylamino-3-methyl-1-pentanol, 4-dimethylamino-2,2-dimethyl-1-butanol, etc. ), N, N-dimethylaminoheptanol (7-dimethylamino-1- Ptanol, 5-dimethylamino-3,3-dimethyl-1-pentanol, etc.), N, N-dimethylaminooctanol (8-dimethylamino-1-octanol, 6-dimethylamino-2-ethyl-1-hexanol, etc.) ) Etc. can be used.

  The reaction with hydroxyethyl (meth) acrylate and isophorone diisocyanate is carried out, for example, in a solution of 2-hydroxyethyl methacrylate containing a catalyst such as di-n-butyltin (IV) dilaurate and a polymerization inhibitor such as p-methoxyphenol. It can be carried out by adding isophorone diisocyanate while stirring at room temperature or under warming, reacting both, and adding an amine compound having a primary hydroxyl group at the terminal at room temperature or under warming. . There is no limitation in the order of both preparations.

  The amount of the isophorone diisocyanate used in that case is preferably 0.5 to 1 equivalent of the hydroxyl group of the compound in the amine compound having hydroxyethyl (meth) acrylate and a terminal hydroxyl group and having an ethylene oxide chain. -2.0 equivalents, more preferably 0.7-1.5 equivalents, particularly preferably 0.8-1.2 equivalents. When the amount of isophorone diisocyanate used is less than 0.5 equivalent, the yield of the polymerizable unsaturated monomer having a cationic functional group is low. On the other hand, when the amount exceeds 2.0 equivalents, unreacted isophorone diisocyanate remains and is obtained. The storage stability of the polymer solution, the pigment dispersion resin, the aqueous pigment dispersion, and the aqueous coating composition may be lowered.

  The monomers (a-1) to (a-4) may contain byproducts.

  The polymerizable unsaturated monomer (a) having a cationic functional group represented by the general formula (1) is generally 3 to 35% by mass, particularly 5 to 5%, based on the total amount of the monomers (a) and (b). It is preferable to use within the range of 33% by mass.

Other polymerizable unsaturated monomers (b)
The other polymerizable unsaturated monomer (b) includes polymerizable unsaturated monomers other than the monomer (a) that can be copolymerized with the monomer (a).

  Examples of other polymerizable unsaturated monomer (b) include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, i-propyl (meth) acrylate, and n-butyl (meth) acrylate. Alkyl (meth) acrylates such as i-butyl (meth) acrylate and tert-butyl (meth) acrylate; vinyl aromatic compounds such as styrene, α-methylstyrene and vinyltoluene; polymerizability having a polyoxyalkylene chain described later Unsaturated monomer (b1); hydroxyl group-containing polymerizable unsaturated monomer (b2) having no polyoxyalkylene chain described later; n-hexyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) Acrylate, nonyl (meth) acrylate, Ridecyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, “isostearyl acrylate” (trade name, manufactured by Osaka Organic Chemical Industry Co., Ltd.), cyclohexyl (meth) acrylate, methylcyclohexyl (meth) acrylate Polymerizable monomers having (cyclo) alkyl groups such as (cyclo) alkyl (meth) acrylates such as tert-butylcyclohexyl (meth) acrylate and cyclododecyl (meth) acrylate; isobornyl (meth) Bridged alicyclic hydrocarbon group-containing polymerizable unsaturated monomers such as acrylate, tricyclodecanyl (meth) acrylate and adamantyl (meth) acrylate; 3-ethyl-3- (meth) acryloyloxymethyloxetane, 3-methyl -3- (Meth) acryloyl Oxetane ring-containing (meth) acrylates such as ruoxymethyloxetane and 3-butyl-3- (meth) acryloyloxymethyloxetane; carboxyl groups such as (meth) acrylic acid, maleic acid, crotonic acid and β-carboxyethyl acrylate Polymerizable unsaturated monomers; (meth) acrylonitrile, (meth) acrylamide, vinyl acetate and the like can be mentioned, and these can be used alone or in combination of two or more.

  Among these, from the viewpoint of smoothness and sharpness of the formed coating film, the other polymerizable unsaturated monomer (b) preferably contains a polymerizable unsaturated monomer (b1) having a polyoxyalkylene chain. . Further, from the viewpoint of water resistance of the formed coating film, the other polymerizable unsaturated monomer (b) preferably contains a hydroxyl group-containing polymerizable unsaturated monomer (b2) having no polyoxyalkylene chain.

  Furthermore, from the viewpoint of color developability, jet blackness, smoothness and sharpness of the formed coating film, other polymerizable unsaturated monomers (b) are alkyl (meth) acrylates, particularly methyl methacrylate, n-butyl (meth). It is preferable to contain an acrylate.

  In addition, from the viewpoint of smoothness and sharpness of the formed coating film, it is particularly preferable that the other polymerizable unsaturated monomer (b) contains a vinyl aromatic compound, particularly styrene.

  The other polymerizable unsaturated monomer (b) is preferably used in a range of generally 65 to 97% by mass, particularly 67 to 95% by mass, based on the total amount of the monomers (a) and (b). is there.

Polymerizable unsaturated monomer having polyoxyalkylene chain (b1)
The polymerizable unsaturated monomer (b1) having a polyoxyalkylene chain is a monomer component for imparting hydrophilicity to the copolymer to be formed, and the polyoxyalkylene chain and the polymerizable unsaturated group in one molecule. Is a monomer containing

  Examples of the polyoxyalkylene chain include a polyoxyethylene chain, a polyoxypropylene chain, a chain composed of a polyoxyethylene block and a polyoxypropylene block, and these polyoxyalkylene chains are generally 200-5. It is preferred to have a molecular weight in the range of 1,000, in particular 250 to 3,500, more particularly 300 to 2,500.

  Representative examples of the polymerizable unsaturated monomer (b1) having a polyoxyalkylene chain include, for example, the general formula (5)

[Wherein, R ³ represents a hydrogen atom or a methyl group, R ⁴ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ⁵ represents an alkylene group having 2 to 4 carbon atoms which may be branched. , M represents an integer of 3 to 150, preferably 10 to 80, more preferably 25 to 50, and the m oxyalkylene units (R ⁵ O) may be the same as or different from each other. ]
The compound shown by can be mentioned.

  Specific examples of the compound of formula (5) include, for example, tetraethylene glycol (meth) acrylate, methoxytetraethylene glycol (meth) acrylate, ethoxytetraethylene glycol (meth) acrylate, and n-butoxytetraethylene glycol (meth) acrylate. , Tetrapropylene glycol (meth) acrylate, methoxytetrapyrene glycol (meth) acrylate, ethoxytetrapropylene glycol (meth) acrylate, n-butoxytetrapropylene glycol (meth) acrylate, polyethylene glycol (meth) acrylate, polypropylene glycol (meta ) Acrylate, methoxy polyethylene glycol (meth) acrylate, ethoxy polyethylene glycol (meth) acrylate Etc. can be mentioned, which may be used either alone or in combination of two or more. Of these, polyethylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate and ethoxypolyethylene glycol (meth) acrylate are preferred, and methoxypolyethylene glycol (meth) acrylate and ethoxypolyethylene glycol (meth) acrylate are preferred. Is particularly preferred.

  In the present specification, “(meth) acrylate” is a general term for acrylate and methacrylate.

  The polymerizable unsaturated monomer (b1) having a polyoxyalkylene chain generally has a molecular weight in the range of 200 to 7,000, particularly 500 to 3,000, more particularly 1,200 to 2,500. Is preferred.

Hydroxyl-containing polymerizable unsaturated monomer having no polyoxyalkylene chain (b2)
The hydroxyl group-containing polymerizable unsaturated monomer (b2) having no polyoxyalkylene chain is a polymerizable unsaturated monomer having at least one hydroxyl group in one molecule and having a polyoxyalkylene chain. It is a polymerizable unsaturated monomer other than the unsaturated monomer (b1).

  Examples of the hydroxyl group-containing polymerizable unsaturated monomer (b2) having no polyoxyalkylene chain include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl ( Monoesterified product of (meth) acrylic acid and dihydric alcohol having 2 to 8 carbon atoms such as (meth) acrylate and 4-hydroxybutyl (meth) acrylate; (meth) acrylic acid and dihydric alcohol having 2 to 8 carbon atoms And ε-caprolactone modified products of monoester compounds, such as allyl alcohol, which can be used alone or in combination of two or more.

  As the monomer (b2), 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate are preferable, Of these, 4-hydroxybutyl (meth) acrylate is particularly preferable.

  In the case where the other polymerizable unsaturated monomer (b) contains a polymerizable unsaturated monomer (b1) having a polyoxyalkylene chain, the monomer (b1) has a color development property, jetness, sharpness, etc. From the viewpoint of the above, it is preferable to use within the range of generally 5 to 40% by mass, particularly 7 to 35% by mass, more particularly 10 to 30% by mass, based on the total amount of the monomers (a) and (b). is there.

  The hydroxyl group-containing polymerizable unsaturated monomer (b2) having no polyoxyalkylene chain is the total amount of the monomers (a) and (b) from the viewpoints of color forming properties, jetness, sharpness and the like of the formed coating film. In general, it is suitable to be used within the range of 5 to 40% by mass, particularly 7 to 35% by mass, more particularly 10 to 30% by mass.

  When the other polymerizable unsaturated monomer (b) contains an alkyl (meth) acrylate, the alkyl (meth) acrylate is generally 35 to 90% by mass based on the total amount of the monomers (a) and (b), It is particularly preferred to use within the range of 40 to 70% by mass, more particularly 45 to 65% by mass.

  When the other polymerizable unsaturated monomer (b) contains a vinyl aromatic compound, the vinyl aromatic compound is generally 0 to 20% by mass, particularly 0%, based on the total amount of the monomers (a) and (b). It is preferable to use within the range of ˜15% by mass, more particularly within the range of 0˜10% by mass.

Copolymer The copolymer used in the pigment-dispersing resin of the present invention is a polymerizable unsaturated monomer (a) having a cationic functional group represented by the general formula (1) described above and other polymerizations. It can be obtained by copolymerizing the polymerizable unsaturated monomer (b). The proportion of the monomers (a) and (b) used in the copolymerization is not strictly limited, and can be changed according to the physical properties desired for the formed copolymer.

  The copolymerization of the monomers (a) and (b) can be carried out by a method known per se, for example, a solution polymerization method in an organic solvent, an emulsion polymerization method in water, etc. Legal is preferred. As the copolymerization method by the solution polymerization method, for example, a mixture of monomers (a) and (b) and a radical polymerization initiator is dissolved or dispersed in an organic solvent, and usually 1 at a temperature of about 80 ° C. to about 200 ° C. A method of heating and polymerizing while stirring for about 10 hours can be mentioned.

  Examples of organic solvents that can be used for copolymerization include hydrocarbon solvents such as heptane, toluene, xylene, octane, mineral spirits; ethyl acetate, n-butyl acetate, isobutyl acetate, ethylene glycol monomethyl ether acetate, diethylene glycol mono Ester solvents such as butyl ether acetate; ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone and cyclohexanone; alcohol solvents such as methanol, ethanol, isopropanol, n-butanol, sec-butanol and isobutanol; n-butyl ether; Ether solvents such as dioxane, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether; SWAZOL 310 manufactured by Cosmo Oil Co., Ltd. Wazoru 1000, and the like aromatic petroleum solvents such as Swasol 1500. These organic solvents can be used alone or in combination of two or more. The said organic solvent can be used in the ratio used normally as 400 mass parts or less with respect to the total amount of monomer (a) and (b).

  Examples of the radical polymerization initiator include ketone peroxides such as cyclohexanone peroxide, 3,3,5-trimethylcyclohexanone peroxide, and methylcyclohexanone peroxide; 1,1-bis (tert-butylperoxy) -3 Peroxyketals such as 1,3,5-trimethylcyclohexane, 1,1-bis (tert-butylperoxy) cyclohexane, n-butyl-4,4-bis (tert-butylperoxy) valerate; cumene hydroperoxide Hydroperoxides such as 2,5-dimethylhexane-2,5-dihydroperoxide; 1,3-bis (tert-butylperoxy-m-isopropyl) benzene, 2,5-dimethyl-2,5 -Di (tert-butyl pero C) Dialkyl peroxides such as hexane, diisopropylbenzene peroxide, tert-butylcumyl peroxide; diacyl peroxides such as decanoyl peroxide, lauroyl peroxide, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide; Peroxycarbonates such as bis (tert-butylcyclohexyl) peroxydicarbonate; peroxyesters such as tert-butylperoxybenzoate and 2,5-dimethyl-2,5-di (benzoylperoxy) hexane Organic peroxide polymerization initiator: 2,2′-azobisisobutyronitrile, 1,1-azobis (cyclohexane-1-carbonitrile), azocumene 2,2′-azobismethylvaleronitrile And azo polymerization initiators such as 4,4′-azobis (4-cyanovaleric acid). Although the usage-amount of these radical polymerization initiators is not specifically limited, It is 0.1-15 mass parts normally per 100 mass parts in total of a monomer (a) and (b), Especially 0.3-10. It is desirable to be within the range of parts by mass.

  In the above polymerization reaction, the method of adding the monomer component and the polymerization initiator is not particularly limited, but the polymerization initiator is divided and dropped in several times from the initial polymerization to the late polymerization rather than charging all at the initial polymerization. It is preferable from the viewpoints of temperature control in the polymerization reaction and suppression of formation of unnecessary cross-linked products such as gelled products.

  The molecular weight of the copolymer thus obtained is not particularly limited, but is generally 5,000 to 100,000 in terms of weight average molecular weight from the viewpoint of water dispersibility and smoothness of the formed coating film. In particular, it is preferably in the range of 8,000 to 70,000, more preferably 10,000 to 50,000.

  In this specification, the number average molecular weight and the weight average molecular weight are the retention time (retention capacity) measured using a gel permeation chromatograph (GPC) and the retention time of a standard polystyrene with a known molecular weight measured under the same conditions. (Retention capacity) is a value obtained by converting to the molecular weight of polystyrene. Specifically, “HLC-8120GPC” (trade name, manufactured by Tosoh Corporation) is used as the gel permeation chromatograph apparatus, and one “TSKgel G4000HXL”, two “TSKgel G3000HXL”, and A total of four “TSKgel G2000HXL” (trade name, all manufactured by Tosoh Corporation) were used, a differential refractometer was used as a detector, mobile phase: tetrahydrofuran, measurement temperature: 40 ° C., flow rate: It is a value obtained by measuring under the condition of 1 mL / min.

  The copolymer preferably has a hydroxyl value in the range of usually 0 to 150 mgKOH / g, particularly 30 to 100 mgKOH / g, more particularly 50 to 90 mgKOH / g, from the viewpoint of the water resistance of the formed coating film. It is.

  The copolymer preferably has an amine value in the range of generally 3 to 100 mgKOH / g, particularly 10 to 80 mgKOH / g, more particularly 15 to 60 mgKOH / g, from the viewpoint of color developability, smoothness and sharpness. It is.

The polymer can be neutralized with an acidic neutralizer to make it water-dispersible or water-soluble. Examples of the acidic neutralizer include phosphoric acid, sulfonic acid, formic acid, acetic acid, propionic acid, n-butanoic acid, n-pentanoic acid, n-hexanoic acid, lactic acid, malic acid, and citric acid. Of these, lactic acid can be preferably used. The acidic neutralizing agents can be used alone or in combination of two or more.

  The pigment-dispersing resin of the present invention comprising the copolymer produced as described above is used for the production of an aqueous pigment dispersion, so that both adsorption to the pigment and dispersion stabilization can be achieved. It is necessary. The monomer (a) component constituting the pigment-dispersing resin of the present invention can improve the adsorption of the pigment-dispersing resin to the pigment, and in particular, adsorption to an inorganic color pigment that has been subjected to oxidation treatment such as carbon black. It can work advantageously both in improving the property and improving the dispersion stability of the resin. Therefore, the pigment dispersion resin of the present invention is extremely useful for preparing an aqueous pigment dispersion together with a pigment, an aqueous medium and the like.

In particular, when the monomer (b1) component is used as the other polymerizable unsaturated monomer, the monomer (b1) component contributes to an improvement in the solubility of the pigment-dispersing resin in the continuous phase (aqueous medium). In particular, it can advantageously work to improve the dispersion stability of the pigment dispersion resin. Further, when the monomer (b2) component is used as another polymerizable unsaturated monomer and a curing agent is used in combination, the monomer (b2) component is a curing agent component contained in the aqueous coating composition of the present invention, for example, It reacts with an amino resin or a polyisocyanate compound which may be blocked, and helps to improve the water resistance of the coating film obtained by being incorporated in the crosslinked coating film. Therefore, the pigment dispersion resin of the present invention is extremely useful for preparing an aqueous pigment dispersion together with a pigment, an aqueous medium and the like, and a pigment dispersion in which the pigment is uniformly dispersed can be obtained. Furthermore, when the pigment dispersion of the present invention is applied to a water-based paint, the pigment is uniformly dispersed, so that a coating film excellent in color developability and sharpness can be obtained.
Aqueous Pigment Dispersion The aqueous pigment dispersion of the present invention is prepared by blending the pigment dispersion resin described above with a pigment, an aqueous medium, a dispersion aid, a basic neutralizer, other additives, and the like. be able to. Moreover, you may mix | blend other pigment dispersion resins other than the pigment dispersion resin of this invention.

  Examples of the pigment include bright pigments such as aluminum powder, copper powder, nickel powder, stainless steel powder, chromium powder, mica-like iron oxide, acid value titanium-coated mica powder, iron oxide-coated mica powder, and bright graphite; pink EB, organic red pigments such as azo and quinacridone, organic blue pigments such as cyanine blue and cyanine green, organic yellow pigments such as benzimidazolone, isoindoline and quinophthalone; titanium oxide, titanium yellow, Examples include inorganic color pigments such as bengara, carbon black, chrome lead, iron oxide, and various fired pigments. Further, extender pigments may be included. These pigments may be subjected to a known surface treatment such as acid / base treatment, coupling agent treatment, plasma treatment, oxidation / reduction treatment and the like. Of these, inorganic color pigments that have been subjected to oxidation treatment such as carbon black are particularly suitable.

  The blending ratio of these pigments is not particularly limited, but is usually 10 to 3,000 parts by weight, particularly 15 to 2,000 parts by weight, more particularly 15 to 1 part per 100 parts by weight of the pigment dispersing resin. , 500 parts by weight is preferable from the viewpoint of pigment dispersibility, dispersion stability, and coloring power of the resulting pigment dispersion.

  Examples of the aqueous medium include water or a water-organic solvent mixed solution obtained by dissolving an organic solvent such as a water-soluble organic solvent in water. Examples of the organic solvent used here include methyl alcohol, ethyl alcohol, isopropyl alcohol, propylene glycol monopropyl ether, ethylene glycol monoble ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol mono Water-soluble organic solvents such as butyl ether, tripropylene glycol monomethyl ether, and 3-methyl 3-methoxybutanol; hardly soluble or insoluble organic solvents such as xylene, toluene, cyclohexanone, hexane, and pentane. These organic solvents can be used alone or in combination of two or more. As the organic solvent, those mainly composed of a water-soluble organic solvent are suitable. The mixing ratio of water and the organic solvent is not particularly limited, but the content of the organic solvent is desirably 50% by weight or less, particularly 35% by weight or less of the mixed solution. The mixing ratio of the aqueous medium is not particularly limited, but is usually 50 to 5,000 parts by weight, particularly 100 to 3,000 parts by weight, more particularly 100 to 2, parts per 100 parts by weight of the pigment dispersing resin. It is preferable from the viewpoint of viscosity at the time of pigment dispersion, pigment dispersibility, dispersion stability and production efficiency to be within the range of 000 parts by weight.

  Other pigment dispersion resins used as necessary include, for example, carboxyl group-containing polymerizable unsaturated monomers such as (meth) acrylic acid and hydroxyl group-containing polymerizable unsaturated compounds such as 2-hydroxyethyl (meth) acrylate. Examples thereof include an acrylic resin obtained by copolymerizing a monomer and another polymerizable unsaturated monomer in the presence of a radical polymerization initiator. The acrylic resin has a weight average molecular weight of about 2,000 to 150,000, particularly 5,000 to 100,000, an acid value of 5 to 150 mgKOH / g, particularly 15 to 100 mgKOH / g, and a hydroxyl value of 10 to 160 mgKOH. / G, particularly those in the range of 30 to 120 mg KOH / g are preferred.

  The ratio (solid content) of the pigment dispersing resin of the present invention and the other pigment dispersing resin is usually 5 to 300 parts by weight of the other pigment dispersing resin per 100 parts by weight of the pigment dispersing resin of the present invention. The range of 20 to 150 parts by weight is appropriate.

  The basic neutralizing agent is used to neutralize a pigment-dispersing resin having a carboxyl group and to make the pigment-dispersing resin water-soluble or water-dispersed. For example, inorganic bases such as ammonium hydroxide, sodium hydroxide, potassium hydroxide; amines such as aminomethylpropanol, aminoethylpropanol, dimethylethanolamine, triethylamine, diethylethanolamine, dimethylaminopropanol, aminomethylpropanol Can be mentioned. The blending amount of these basic neutralizing agents is not less than the amount necessary for water-dispersing or water-dispersing the pigment dispersing resin, and the neutralization equivalent of carboxyl groups in the pigment dispersing resin is usually 0.00. The ratio is preferably 3 to 1.5, particularly 0.4 to 1.3.

  Examples of the dispersion aid used as necessary include Disper BYK-182 and Disper BYK-180 manufactured by BYK-Chemie, Solsperse 12000 and Solsperse 27000 manufactured by Abycia, and other additives. , Antifoaming agents, antiseptics, rust inhibitors, plasticizers and the like. In consideration of the dispersibility of the pigment, the stability of the paste, the let-down stability, and the coating film performance, these blending amounts are desirably 50 parts or less with respect to 100 parts by weight of the pigment dispersion resin.

The aqueous pigment dispersion can be prepared by uniformly mixing and dispersing the above-described components using a dispersing machine such as a paint shaker, a sand mill, a ball mill, an LMZ mill, or a DCP pearl mill.
Aqueous paint composition The aqueous pigment dispersion prepared as described above comprises a film-forming resin, and optionally a curing agent, an aqueous medium, a hydrophobic medium, a curing catalyst, a basic neutralizing agent, and an ultraviolet absorber. , UV stabilizers, coating surface modifiers, antioxidants, fluidity modifiers, silane coupling agents, and other paint additives can be blended and stably dispersed in an aqueous medium to form an aqueous coating composition. it can.

As the film-forming resin, a known water-soluble or water-dispersible film-forming resin which has been conventionally used as a binder component for water-based paints can be used. Examples of the resin include acrylic resin, polyester resin, alkyd resin, polyurethane resin and the like, and these can be used alone or in combination of two or more. The film-forming resin preferably has a functional group such as a hydroxyl group, a carboxyl group, or an epoxy group, and particularly preferably a hydroxyl group-containing resin.

  The pigment-dispersing resin of the present invention is not included in the film-forming resin. Therefore, the film-forming resin is a film-forming resin other than the pigment-dispersible resin of the present invention.

  The aqueous coating composition of the present invention may further contain a curing agent described later. When the aqueous coating composition of the present invention contains a curing agent, the film-forming resin usually has a functional group such as a hydroxyl group, a carboxyl group, and an epoxy group, and is cured by reacting with the curing agent. A resin (base resin) capable of forming a film is used. Examples of the base resin include acrylic resin, polyester resin, alkyd resin, and polyurethane resin. Among these, the base resin is preferably a hydroxyl group-containing resin, and more preferably a hydroxyl group-containing acrylic resin and / or a hydroxyl group-containing polyester resin. Moreover, it is more preferable to use together a hydroxyl-containing acrylic resin and a hydroxyl-containing polyester resin from a viewpoint of the smoothness of a coating film, and the improvement of glitter (flip-flop property). Moreover, as a ratio in the case of using together, based on the total amount of a hydroxyl-containing acrylic resin and a hydroxyl-containing polyester resin, the former is about 20-80 mass%, especially about 30-70 mass%, and the latter is 80-20. It is preferably about mass%, particularly about 70-30 mass%.

  When the film-forming resin has an acid group such as a carboxyl group, the acid value is preferably about 5 to 150 mgKOH / g, more preferably about 10 to 100 mgKOH / g, and 15 to 80 mgKOH / g. More preferably, it is about g. When the film-forming resin has a hydroxyl group, the hydroxyl value is preferably about 1 to 200 mgKOH / g, more preferably about 2 to 180 mgKOH / g, and about 5 to 170 mgKOH / g. Is more preferable.

Hydroxyl group-containing acrylic resin As the hydroxyl group-containing acrylic resin, for example, a hydroxyl group-containing polymerizable unsaturated monomer and other polymerizable unsaturated monomers copolymerizable with the hydroxyl group-containing polymerizable unsaturated monomer are known per se, for example, It can be produced by copolymerization by a method such as a solution polymerization method in an organic solvent or an emulsion polymerization method in water.

  The hydroxyl group-containing polymerizable unsaturated monomer is a compound having at least one hydroxyl group and one polymerizable unsaturated bond in one molecule. As the hydroxyl group-containing polymerizable unsaturated monomer, for example, it can be appropriately selected from the monomer components (b1) and (b2) described in the description of the pigment dispersion resin of the present invention. These can be used alone or in combination of two or more.

  Examples of the other polymerizable unsaturated monomer copolymerizable with the hydroxyl group-containing polymerizable unsaturated monomer include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, and i-propyl (meth). ) Acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, tert-butyl (meth) acrylate, n-hexyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate , Nonyl (meth) acrylate, tridecyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, “isostearyl acrylate” (trade name, manufactured by Osaka Organic Chemical Industry Co., Ltd.), cyclohexyl (meth) acrylate, Methylcyclohex (Cyclo) alkyl (meth) acrylates such as ru (meth) acrylate, t-butylcyclohexyl (meth) acrylate, cyclododecyl (meth) acrylate; isobornyl (meth) acrylate, adamantyl (meth) acrylate, etc. Bridged alicyclic hydrocarbon group-containing polymerizable unsaturated monomers; vinyl aromatic compounds such as styrene, α-methylstyrene, vinyltoluene; vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silane Polymerizable unsaturated monomers having alkoxysilyl groups such as γ- (meth) acryloyloxypropyltrimethoxysilane, γ- (meth) acryloyloxypropyltriethoxysilane; perfluorobutylethyl (meth) acrylate, perfluorooctyl Perfluoroalkyl (meth) acrylate such as ethyl (meth) acrylate; polymerizable unsaturated monomer having a fluorinated alkyl group such as fluoroolefin; polymerizable unsaturated monomer having a photopolymerizable functional group such as maleimide group; N- Vinyl compounds such as vinyl pyrrolidone, ethylene, butadiene, chloroprene, vinyl propionate and vinyl acetate; carboxyl group-containing polymerizable unsaturated monomers such as (meth) acrylic acid, maleic acid, crotonic acid and β-carboxyethyl acrylate; ) Nitrogen-containing polymerizable unsaturated monomers such as acrylonitrile, (meth) acrylamide, dimethylaminopropyl (meth) acrylamide, dimethylaminoethyl (meth) acrylate, adducts of glycidyl (meth) acrylate and amines; (Meth) acrylate, β-methylglycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, 3,4-epoxycyclohexylethyl (meth) acrylate, 3,4-epoxycyclohexylpropyl (meth) acrylate , Epoxy group-containing polymerizable unsaturated monomers such as allyl glycidyl ether; (meth) acrylate having a polyoxyethylene chain whose molecular terminal is an alkoxy group; 2-acrylamido-2-methylpropanesulfonic acid, allylsulfonic acid, styrenesulfone Polymerizable unsaturated monomers having a sulfonic acid group such as sodium acid salt, sulfoethyl methacrylate and sodium salt or ammonium salt thereof; 2-acryloyloxyethyl acid phosphate, 2-methacryloylo Polymerizable unsaturated monomer having a phosphate group such as xylethyl acid phosphate, 2-acryloyloxypropyl acid phosphate, 2-methacryloyloxypropyl acid phosphate; 2-hydroxy-4- (3-methacryloyloxy-2-hydroxypropoxy) Benzophenone, 2-hydroxy-4- (3-acryloyloxy-2-hydroxypropoxy) benzophenone, 2,2′-dihydroxy-4- (3-methacryloyloxy-2-hydroxypropoxy) benzophenone, 2,2′-dihydroxy- UV-absorbing functional groups such as 4- (3-acryloyloxy-2-hydroxypropoxy) benzophenone and 2- (2′-hydroxy-5′-methacryloyloxyethylphenyl) -2H-benzotriazole Polymerizable unsaturated monomer having; 4- (meth) acryloyloxy-1,2,2,6,6-pentamethylpiperidine, 4- (meth) acryloyloxy-2,2,6,6-tetramethylpiperidine, 4 -Cyano-4- (meth) acryloylamino-2,2,6,6-tetramethylpiperidine, 1- (meth) acryloyl-4- (meth) acryloylamino-2,2,6,6-tetramethylpiperidine, 1- (meth) acryloyl-4-cyano-4- (meth) acryloylamino-2,2,6,6-tetramethylpiperidine, 4-crotonoyloxy-2,2,6,6-tetramethylpiperidine, 4 -Crotonoylamino-2,2,6,6-tetramethylpiperidine, 1-crotonoyl-4-crotonoyloxy-2,2,6,6-tetramethyl UV-stable polymerizable unsaturated monomers such as piperidine; acrolein, diacetone acrylamide, diacetone methacrylamide, acetoacetoxyethyl methacrylate, formylstyrol, vinyl alkyl ketones having 4 to 7 carbon atoms (eg, vinyl methyl ketone, Examples thereof include polymerizable unsaturated monomer compounds having a carbonyl group such as vinyl ethyl ketone and vinyl butyl ketone, and these can be used alone or in combination of two or more.

  The hydroxyl group-containing acrylic resin preferably has an amide group. The hydroxyl group-containing acrylic resin having an amide group includes, for example, (meth) acrylamide, N, N-dimethylamino as one of other polymerizable unsaturated monomers copolymerizable with the hydroxyl group-containing polymerizable unsaturated monomer. It can be produced by using an amide group-containing polymerizable unsaturated monomer such as propyl (meth) acrylamide.

  The proportion of the hydroxyl group-containing polymerizable unsaturated monomer used in the production of the hydroxyl group-containing acrylic resin is preferably about 1 to 50% by mass, more preferably about 2 to 40% by mass, based on the total amount of monomer components. 3 to 30% by mass is more preferable.

  The hydroxyl group-containing acrylic resin preferably has an acid value of about 0.1 to 200 mgKOH / g, and about 2 to 150 mgKOH / g, from the viewpoints of storage stability of the paint and water resistance of the resulting coating film. More preferably, it is more preferably about 5 to 100 mgKOH / g.

  The hydroxyl group-containing acrylic resin preferably has a hydroxyl value of about 0.1 to 200 mgKOH / g, more preferably about 2 to 150 mgKOH / g, from the viewpoint of water resistance of the resulting coating film. Preferably, it is about 5-100 mgKOH / g.

  As the hydroxyl group-containing acrylic resin, a core-shell type water-dispersible hydroxyl group-containing acrylic resin is used alone, or a core-shell type water-dispersible hydroxyl group is used from the viewpoint of improving the smoothness and glitter of the formed coating film. It is preferable to use the containing acrylic resin and the water-soluble acrylic resin in combination.

  The core-shell type water-dispersible hydroxyl group-containing acrylic resin is a polymerizable unsaturated monomer having two or more polymerizable unsaturated groups in one molecule from the viewpoint of improving the smoothness and glitter of the formed coating film. A core which is a copolymer (I) having about 0.1 to 30% by mass and about 70 to 99.9% by mass of a polymerizable unsaturated monomer having one polymerizable unsaturated group per molecule. Part, about 1 to 40% by weight of a hydroxyl group-containing polymerizable unsaturated monomer, about 5 to 50% by weight of a hydrophobic polymerizable unsaturated monomer, and about 10 to 94% by weight of another polymerizable unsaturated monomer are used as a copolymerization component. A core-shell type water-dispersible hydroxyl group-containing acrylic resin comprising a shell part which is a copolymer (II) is preferred. Further, the ratio of copolymer (I) / copolymer (II) is about 10/90 to 90/10 in terms of solid content mass ratio from the viewpoint of improving the smoothness and glitter of the formed coating film. Preferably, about 50/50 to 85/15 is more preferable, and about 65/35 to 80/20 is more preferable.

  Examples of the polymerizable unsaturated monomer having two or more polymerizable unsaturated groups in one molecule used as the monomer for the core copolymer (I) include allyl (meth) acrylate, ethylene glycol di (meth) acrylate, Triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, 1,4-butanediol di (meth) acrylate , Neopentyl glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tetra (meth) acrylate, glycerol di (meth) acrylate, 1,1,1 -Birds Hydroxymethylethane di (meth) acrylate, 1,1,1-trishydroxymethylethane tri (meth) acrylate, 1,1,1-trishydroxymethylpropane tri (meth) acrylate, triallyl isocyanurate, diallyl terephthalate, divinyl Examples include benzene. These monomers can be used alone or in combination of two or more.

  The polymerizable unsaturated monomer having two or more polymerizable unsaturated groups in one molecule has a function of imparting a crosslinked structure to the core copolymer (I). The use ratio of the polymerizable unsaturated monomer having two or more polymerizable unsaturated groups in one molecule can be appropriately determined according to the degree of crosslinking of the core copolymer (I). About 0.1 to 30% by mass based on the total amount of the polymerizable unsaturated monomer having two or more saturated groups in one molecule and the polymerizable unsaturated monomer having one polymerizable unsaturated group in one molecule It is preferable that it is about 0.5-10 mass%, and it is still more preferable that it is about 1-7 mass%.

  Examples of the polymerizable unsaturated monomer having two or more polymerizable unsaturated groups per molecule include methylene bis (meth) acrylamide and ethylene bis (meth) from the viewpoint of suppressing metallic unevenness of the resulting coating film. It is preferable to use an amide group-containing monomer such as acrylamide. The amount used in the case of using this amide group-containing monomer is a polymerizable unsaturated monomer having two or more polymerizable unsaturated groups in one molecule and a polymerizable having one polymerizable unsaturated group in one molecule. Based on the total amount of unsaturated monomers, it is preferably about 0.1 to 25% by mass, more preferably about 0.5 to 8% by mass, and further about 1 to 4% by mass. preferable.

  The polymerizable unsaturated monomer having one polymerizable unsaturated group in one molecule used as a monomer for the core copolymer (I) is a polymerizable unsaturated monomer having two or more polymerizable unsaturated groups in one molecule. A polymerizable unsaturated monomer copolymerizable with a saturated monomer.

  Specific examples of the polymerizable unsaturated monomer having one polymerizable unsaturated group per molecule include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, i-propyl ( (Meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, tert-butyl (meth) acrylate, n-hexyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) Acrylate, nonyl (meth) acrylate, tridecyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, cyclohexyl (meth) acrylate, methylcyclohexyl (meth) acrylate, t-butyl Hexyl (meth) acrylate, cyclododecyl (meth) acrylate, alkyl or cycloalkyl (meth) acrylate such as tricyclodecanyl (meth) acrylate; bridged alicyclic such as isobornyl (meth) acrylate and adamantyl (meth) acrylate Hydrocarbon group-containing polymerizable unsaturated monomer; polymerizable unsaturated monomer having a tricyclodecenyl group such as tricyclodecenyl (meth) acrylate; benzyl (meth) acrylate, styrene, α-methylstyrene, vinyltoluene Aromatic ring-containing polymerizable unsaturated monomers such as vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silane, γ- (meth) acryloyloxypropyltrimethoxysilane, γ- (meth) acryloyloxypropiyl Polymerizable unsaturated monomer having alkoxysilyl group such as triethoxysilane; Perfluoroalkyl (meth) acrylate such as perfluorobutylethyl (meth) acrylate and perfluorooctylethyl (meth) acrylate; Fluorinated alkyl such as fluoroolefin Polymerizable unsaturated monomer having a group; polymerizable unsaturated monomer having a photopolymerizable functional group such as a maleimide group; vinyl compounds such as N-vinylpyrrolidone, ethylene, butadiene, chloroprene, vinyl propionate and vinyl acetate; (Meth) acrylic acid such as hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate and divalent alcohol having 2 to 8 carbon atoms Monoesterified product with alcohol, ε-caprolactone modified product of monoesterified product of (meth) acrylic acid and dihydric alcohol having 2 to 8 carbon atoms, N-hydroxymethyl (meth) acrylamide, allyl alcohol, molecule Hydroxyl group-containing polymerizable unsaturated monomers such as (meth) acrylate having a polyoxyethylene chain having a terminal hydroxyl group; carboxyl group-containing polymerizable monomers such as (meth) acrylic acid, maleic acid, crotonic acid, and β-carboxyethyl acrylate Saturated monomer: (meth) acrylonitrile, (meth) acrylamide, N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylamide, glycidyl ( Adducts of (meth) acrylate and amines, etc. A nitrogen-containing polymerizable unsaturated monomer; glycidyl (meth) acrylate, β-methylglycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, 3,4-epoxycyclohexylethyl (meth) acrylate, 3, Examples include epoxy group-containing polymerizable unsaturated monomers such as 4-epoxycyclohexylpropyl (meth) acrylate and allyl glycidyl ether; (meth) acrylates having a polyoxyethylene chain whose molecular terminal is an alkoxy group. These monomers can be used alone or in combination of two or more depending on the performance required for the core-shell type water-dispersible hydroxyl group-containing acrylic resin.

  The hydroxyl group-containing polymerizable unsaturated monomer used as the monomer for the shell copolymer (II) can improve the water resistance of the coating film by introducing a hydroxyl group that undergoes a crosslinking reaction with the curing agent into the obtained water-dispersible acrylic resin. While improving, it has the function to improve stability in the aqueous medium of this water-dispersible acrylic resin. Examples of the hydroxyl group-containing polymerizable unsaturated monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate and the like ( Monoesterified product of (meth) acrylic acid and C2-C8 dihydric alcohol; ε-caprolactone modified product of monoesterified product of (meth) acrylic acid and C2-C8 dihydric alcohol; N- Examples thereof include hydroxymethyl (meth) acrylamide, allyl alcohol, and (meth) acrylate having a polyoxyethylene chain whose molecular end is a hydroxyl group. These monomers can be used alone or in combination of two or more. As the hydroxyl group-containing polymerizable unsaturated monomer, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, or the like is used. preferable.

  From the viewpoint of excellent stability of the core / shell type water-dispersible hydroxyl group-containing acrylic resin in an aqueous medium and water resistance of the resulting coating film, Based on the total mass of monomers constituting II), it is preferably about 1 to 40% by mass, more preferably about 4 to 25% by mass, and further preferably about 7 to 19% by mass.

  The hydrophobic polymerizable unsaturated monomer used as the monomer for the shell copolymer (II) is a linear, branched or cyclic saturated or unsaturated hydrocarbon having 6 or more carbon atoms, preferably 6 to 18 carbon atoms. A monomer having a group, and a monomer having a hydrophilic group such as a hydroxyl group-containing polymerizable unsaturated monomer is excluded. Examples of the monomer include n-hexyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, tridecyl (meth) acrylate, lauryl (meth) acrylate, and stearyl (meth). ) Alkyls such as acrylate, isostearyl (meth) acrylate, cyclohexyl (meth) acrylate, methylcyclohexyl (meth) acrylate, t-butylcyclohexyl (meth) acrylate, cyclododecyl (meth) acrylate, tricyclodecanyl (meth) acrylate Or cycloalkyl (meth) acrylate; bridged alicyclic hydrocarbon group-containing polymerizable unsaturated monomer such as isobornyl (meth) acrylate and adamantyl (meth) acrylate; benzyl Meth) acrylate, styrene, alpha-methyl styrene, can be mentioned aromatic ring-containing polymerizable unsaturated monomers such as vinyl toluene. These monomers can be used alone or in combination of two or more.

  In addition, from the viewpoint of improving the smoothness and brightness of the resulting coating film, the above-mentioned hydrophobic polymerizable unsaturated monomer is a polymerizable unsaturated monomer having an alkyl group having 6 to 18 carbon atoms and / or aromatic ring-containing polymerization. It is preferable to use a polymerizable unsaturated monomer. In particular, it is more preferable to use styrene.

  From the viewpoint of excellent stability of the core-shell type water-dispersible hydroxyl group-containing acrylic resin in an aqueous medium and water resistance of the resulting coating film, the proportion of the hydrophobic polymerizable unsaturated monomer used is a shell copolymer ( II) is preferably about 5 to 50% by mass, more preferably about 7 to 40% by mass, and still more preferably about 9 to 30% by mass, based on the total mass of monomers constituting II).

The other polymerizable unsaturated monomer used as the monomer for the shell copolymer (II) is a polymerizable unsaturated monomer other than the hydroxyl group-containing polymerizable unsaturated monomer and the hydrophobic polymerizable unsaturated monomer. Examples of the monomer include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, i-propyl (meth) acrylate, n-butyl (meth) acrylate, and i-butyl (meth) acrylate. , Alkyl such as tert-butyl (meth) acrylate or cycloalkyl (meth) acrylate; carboxyl group-containing polymerizable unsaturated monomer, and the like. These monomers can be used alone or in combination of two or more.
Specific examples of the carboxyl group-containing polymerizable unsaturated monomer are the same as those exemplified as the monomer for the core copolymer (I). As the carboxyl group-containing polymerizable unsaturated monomer, it is particularly preferable to use acrylic acid and / or methacrylic acid. By including the carboxyl group-containing polymerizable unsaturated monomer as the other polymerizable unsaturated monomer, the stability of the obtained core-shell type water-dispersible hydroxyl group-containing acrylic resin in an aqueous medium can be secured.

  In the case of using the carboxyl group-containing polymerizable unsaturated monomer, the use ratio of the shell / shell type water-dispersible hydroxyl group-containing acrylic resin from the viewpoint of excellent stability in an aqueous medium and excellent water resistance of the resulting coating film. The total amount of monomers constituting the partial copolymer (II) is preferably about 1 to 30% by mass, more preferably about 5 to 25% by mass, and about 7 to 19% by mass. Is more preferable.

  In addition, the other polymerizable unsaturated monomer used as the monomer for the shell copolymer (II) has two or more polymerizable unsaturated groups in one molecule from the viewpoint of improving the glitter of the resulting coating film. It is preferable not to use a polymerizable unsaturated monomer and to make the copolymer (II) uncrosslinked.

  The ratio of copolymer (I) / copolymer (II) in the core-shell type water-dispersible hydroxyl group-containing acrylic resin is 10/90 to 90/10 in terms of solid content mass ratio from the viewpoint of improving the appearance of the coating film. Is preferably about 50/50 to 85/15, and more preferably about 65/35 to 80/20.

  The core-shell type water-dispersible hydroxyl group-containing acrylic resin preferably has a hydroxyl value of about 1 to 70 mgKOH / g, and about 2 to 50 mgKOH / g, from the viewpoint of excellent water resistance of the resulting coating film. Is more preferable, and it is still more preferable that it is about 5-30 mgKOH / g.

  The core-shell type water-dispersible hydroxyl group-containing acrylic resin preferably has an acid value of about 5 to 90 mgKOH / g from the viewpoint of excellent storage stability of the coating composition and water resistance of the resulting coating film. More preferably, it is about 8-50 mgKOH / g, and more preferably about 10-35 mgKOH / g.

  The core-shell type water-dispersible hydroxyl group-containing acrylic resin comprises about 0.1 to 30% by mass of a polymerizable unsaturated monomer having two or more polymerizable unsaturated groups in one molecule and one molecule of polymerizable unsaturated group. After emulsion polymerization of a monomer mixture consisting of about 70 to 99.9% by weight of a polymerizable unsaturated monomer having one therein to obtain an emulsion of the core copolymer (I), hydroxyl group-containing polymerization is carried out in this emulsion. A monomer mixture comprising about 1 to 40% by weight of the polymerizable unsaturated monomer, about 5 to 50% by weight of the hydrophobic polymerizable unsaturated monomer, and about 10 to 94% by weight of the other polymerizable unsaturated monomer is added, and further emulsion polymerization is performed. To obtain a shell copolymer (II).

  Emulsion polymerization for preparing an emulsion of the core copolymer (I) can be performed by a conventionally known method. For example, it can be carried out by emulsion polymerization of the monomer mixture using a polymerization initiator in the presence of an emulsifier.

  As the emulsifier, an anionic emulsifier and a nonionic emulsifier are suitable. Examples of the anionic emulsifier include sodium salts and ammonium salts such as alkylsulfonic acid, alkylbenzenesulfonic acid, and alkylphosphoric acid. Nonionic emulsifiers include, for example, polyoxyethylene oleyl ether, polyoxyethylene stearyl ether, polyoxyethylene lauryl ether, polyoxyethylene tridecyl ether, polyoxyethylene phenyl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene Examples include ethylene octyl phenyl ether, polyoxyethylene monolaurate, polyoxyethylene monostearate, polyoxyethylene monooleate, sorbitan monolaurate, sorbitan monostearate, sorbitan trioleate, polyoxyethylene sorbitan monolaurate It is done.

  Also, a polyoxyalkylene group-containing anionic emulsifier having an anionic group and a polyoxyalkylene group such as a polyoxyethylene group or a polyoxypropylene group in one molecule; an anionic group and radically polymerizable unsaturated in one molecule It is also possible to use reactive anionic emulsifiers having groups. Of these, it is preferable to use a reactive anionic emulsifier.

  Examples of the reactive anionic emulsifier include sodium salts of sulfonic acid compounds having radically polymerizable unsaturated groups such as allyl groups, methallyl groups, (meth) acryloyl groups, propenyl groups, butenyl groups, and ammonium salts of the sulfonic acid compounds. Etc. Among these, an ammonium salt of a sulfonic acid compound having a radically polymerizable unsaturated group is preferable because the resulting coating film is excellent in water resistance. Examples of the commercially available ammonium salt of the sulfonic acid compound include “Latemul S-180A” (trade name, manufactured by Kao Corporation).

  Of the ammonium salts of sulfonic acid compounds having radically polymerizable unsaturated groups, ammonium salts of sulfonic acid compounds having radically polymerizable unsaturated groups and polyoxyalkylene groups are more preferred. Examples of commercially available ammonium salts of sulfonic acid compounds having a radical polymerizable unsaturated group and a polyoxyalkylene group include “AQUALON KH-10” (trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), “Latemul PD- 104 ”(trade name, manufactured by Kao Corporation),“ ADEKA rear soap SR-1025 ”(trade name, manufactured by ADEKA), and the like.

  The amount of the emulsifier used is preferably about 0.1 to 15% by mass, more preferably about 0.5 to 10% by mass, and about 1 to 5% by mass based on the total amount of all monomers used. Further preferred.

  Examples of the polymerization initiator include benzoyl peroxide, octanoyl peroxide, lauroyl peroxide, stearoyl peroxide, cumene hydroperoxide, tert-butyl peroxide, tert-butyl peroxylaurate, and tert-butyl peroxy. Organic peroxides such as isopropyl carbonate, tert-butyl peroxyacetate, diisopropylbenzene hydroperoxide; azobisisobutyronitrile, azobis (2,4-dimethylvaleronitrile), azobis (2-methylpropiononitrile), azobis (2-methylbutyronitrile), 4,4′-azobis (4-cyanobutanoic acid), dimethylazobis (2-methylpropionate), azobis [2-methyl-N- (2-hydro Cyethyl) -propionamide], azo compounds such as azobis {2-methyl-N- [2- (1-hydroxybutyl)]-propionamide}; persulfates such as potassium persulfate, ammonium persulfate, sodium persulfate, etc. Is mentioned. These polymerization initiators can be used singly or in combination of two or more. Moreover, it is good also as a redox initiator by using together with reducing agents, such as saccharide | sugar, sodium formaldehyde sulfoxylate, and an iron complex, as needed to the said polymerization initiator.

  In general, the amount of the polymerization initiator used is preferably about 0.1 to 5% by mass, more preferably about 0.2 to 3% by mass, based on the total mass of all monomers used. The method for adding the polymerization initiator is not particularly limited, and can be appropriately selected according to the type and amount thereof. For example, it may be previously contained in the monomer mixture or the aqueous medium, or may be added all at once during the polymerization, or may be added dropwise.

  The core-shell type water-dispersible hydroxyl group-containing acrylic resin is prepared by adding a hydroxyl group-containing polymerizable unsaturated monomer, a hydrophobic polymerizable unsaturated monomer, and other polymerizable monomers to the emulsion of the core copolymer (I) obtained above. It can be obtained by adding a monomer mixture comprising a saturated monomer and further polymerizing to form a shell copolymer (II).

  The monomer mixture forming the shell copolymer (II) can appropriately contain components such as the polymerization initiator, chain transfer agent, reducing agent, and emulsifier, if necessary. The monomer mixture can be dropped as it is, but it is desirable to drop the monomer mixture as a monomer emulsion obtained by dispersing the monomer mixture in an aqueous medium. In this case, the particle size of the monomer emulsion is not particularly limited.

As a polymerization method of the monomer mixture for forming the shell copolymer (II), for example, the monomer mixture or an emulsion thereof is dripped in a batch or gradually, and an emulsion of the core copolymer (I) is obtained. And a method of heating to an appropriate temperature while stirring.
The core-shell type water-dispersible hydroxyl group-containing acrylic resin thus obtained has a polymerizable unsaturated monomer having two or more polymerizable unsaturated groups in one molecule and a polymerization having one polymerizable unsaturated group in one molecule. Copolymerization of a monomer mixture comprising a copolymer (I) of a monomer mixture comprising a polymerizable unsaturated monomer and a hydroxyl group-containing polymerizable unsaturated monomer, a hydrophobic polymerizable unsaturated monomer and other polymerizable unsaturated monomers It has a multi-layer structure with the union (II) as a shell part.

The core-shell type water-dispersible hydroxyl group-containing acrylic resin thus obtained can generally have an average particle diameter in the range of about 10 to 1,000 nm, particularly about 20 to 500 nm.
In this specification, the average particle diameter of the core-shell type water-dispersible hydroxyl group-containing acrylic resin is a value measured at 20 ° C. after diluting with deionized water by a conventional method using a submicron particle size distribution analyzer. is there. As the submicron particle size distribution measuring device, for example, “COULTER N4 type” (trade name, manufactured by Beckman Coulter, Inc.) can be used.

  In order to improve the mechanical stability of the particles of the core-shell type water-dispersible hydroxyl group-containing acrylic resin, it is desirable to neutralize acid groups such as carboxyl groups of the water-dispersible acrylic resin with a neutralizing agent. The neutralizing agent is not particularly limited as long as it can neutralize an acid group. For example, sodium hydroxide, potassium hydroxide, trimethylamine, 2- (dimethylamino) ethanol, 2-amino-2-methyl- Examples include 1-propanol, triethylamine, and aqueous ammonia. These neutralizing agents are desirably used in such an amount that the pH of the aqueous dispersion of the water-dispersible acrylic resin after neutralization is about 6.5 to 9.0.

  As the hydroxyl group-containing acrylic resin, a hydroxyl group-containing acrylic resin modified with polyester and / or polyurethane resin can also be used.

Hydroxyl-containing polyester resin In the aqueous coating composition of the present invention, the use of a hydroxyl-containing polyester resin as the film-forming resin can improve the coating performance such as smoothness of the resulting coating.

  The hydroxyl group-containing polyester resin can be usually produced by an esterification reaction or an ester exchange reaction between an acid component and an alcohol component.

  As said acid component, the compound normally used as an acid component can be used at the time of manufacture of a polyester resin. Examples of the acid component include an aliphatic polybasic acid, an alicyclic polybasic acid, an aromatic polybasic acid, and the like.

  The aliphatic polybasic acid is generally an aliphatic compound having two or more carboxyl groups in one molecule, an acid anhydride of the aliphatic compound, and an esterified product of the aliphatic compound. Examples of the aliphatic polybasic acid include succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, brassic acid, octadecanedioic acid, and citric acid. Aliphatic polyvalent carboxylic acid; anhydride of the aliphatic polyvalent carboxylic acid; esterified product of lower alkyl having about 1 to 4 carbon atoms of the aliphatic polyvalent carboxylic acid. The above aliphatic polybasic acids can be used alone or in combination of two or more.

  As the aliphatic polybasic acid, it is particularly preferable to use adipic acid and / or adipic anhydride from the viewpoint of the smoothness of the resulting coating film.

  The alicyclic polybasic acid is generally a compound having one or more alicyclic structures and two or more carboxyl groups in one molecule, an acid anhydride of the compound, and an esterified product of the compound. The alicyclic structure is mainly a 4- to 6-membered ring structure. Examples of the alicyclic polybasic acid include 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 4-cyclohexene-1,2-dicarboxylic acid, 3-methyl- Alicyclic polycarboxylic acids such as 1,2-cyclohexanedicarboxylic acid, 4-methyl-1,2-cyclohexanedicarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, 1,3,5-cyclohexanetricarboxylic acid; An anhydride of an alicyclic polyvalent carboxylic acid; an esterified product of a lower alkyl having about 1 to 4 carbon atoms of the alicyclic polyvalent carboxylic acid. The said alicyclic polybasic acid can be used individually or in combination of 2 or more types.

  As said alicyclic polybasic acid, from a smoothness viewpoint of the coating film obtained, 1, 2- cyclohexane dicarboxylic acid, 1, 2- cyclohexane dicarboxylic acid anhydride, 1, 3- cyclohexane dicarboxylic acid, 1, 4 -Cyclohexanedicarboxylic acid, 4-cyclohexene-1,2-dicarboxylic acid, 4-cyclohexene-1,2-dicarboxylic anhydride are preferably used, among which 1,2-cyclohexanedicarboxylic acid and / or 1,2 -More preferred is the use of cyclohexanedicarboxylic anhydride.

  The aromatic polybasic acid is generally an aromatic compound having two or more carboxyl groups in one molecule, an acid anhydride of the aromatic compound, and an esterified product of the aromatic compound, for example, phthalic acid , Isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, 4,4′-biphenyldicarboxylic acid, trimellitic acid, pyromellitic acid and other aromatic polycarboxylic acids; anhydrides of the aromatic polycarboxylic acids; aromatics Examples thereof include esterified products of lower alkyl having about 1 to 4 carbon atoms of polyvalent carboxylic acid. The aromatic polybasic acids can be used alone or in combination of two or more.

  As the aromatic polybasic acid, it is preferable to use phthalic acid, phthalic anhydride, isophthalic acid, trimellitic acid, or trimellitic anhydride.

  Moreover, acid components other than the said aliphatic polybasic acid, alicyclic polybasic acid, and aromatic polybasic acid can also be used. Such acid component is not particularly limited, for example, coconut oil fatty acid, cottonseed oil fatty acid, hemp seed oil fatty acid, rice bran oil fatty acid, fish oil fatty acid, tall oil fatty acid, soybean oil fatty acid, linseed oil fatty acid, tung oil fatty acid, rapeseed oil fatty acid, Fatty acids such as castor oil fatty acid, dehydrated castor oil fatty acid, safflower oil fatty acid; lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, benzoic acid, p-tert-butylbenzoic acid, cyclohexane Examples thereof include monocarboxylic acids such as acid and 10-phenyloctadecanoic acid; hydroxycarboxylic acids such as lactic acid, 3-hydroxybutanoic acid, and 3-hydroxy-4-ethoxybenzoic acid. These acid components can be used alone or in combination of two or more.

  As said alcohol component, the polyhydric alcohol which has a 2 or more hydroxyl group in 1 molecule can be used conveniently. Examples of the polyhydric alcohol include ethylene glycol, propylene glycol, diethylene glycol, trimethylene glycol, tetraethylene glycol, triethylene glycol, dipropylene glycol, 1,4-butanediol, 1,3-butanediol, 2,3 -Butanediol, 1,2-butanediol, 3-methyl-1,2-butanediol, 2-butyl-2-ethyl-1,3-propanediol, 1,2-pentanediol, 1,5-pentanediol 1,4-pentanediol, 2,4-pentanediol, 2,3-dimethyltrimethylene glycol, tetramethylene glycol, 3-methyl-4,3-pentanediol, 3-methyl-1,5-pentanediol, 2,2,4-trimethyl-1,3-pentane 1,6-hexanediol, 1,5-hexanediol, 1,4-hexanediol, 2,5-hexanediol, neopentyl glycol, 1,4-cyclohexanedimethanol, tricyclodecane dimethanol, water Dihydric alcohols such as hydrogenated bisphenol A and hydrogenated bisphenol F; polylactone diols obtained by adding lactones such as ε-caprolactone to these dihydric alcohols; ester diols such as bis (hydroxyethyl) terephthalate; alkylenes of bisphenol A Oxide adducts, polyether diols such as polyethylene glycol, polypropylene glycol, polybutylene glycol; glycerin, trimethylolethane, trimethylolpropane, diglycerin, triglycerin, 1,2,6- Trivalent or higher alcohols such as hexanetriol, pentaerythritol, dipentaerythritol, tris (2-hydroxyethyl) isocyanuric acid, sorbitol, mannitol; lactones such as ε-caprolactone are added to these trivalent or higher alcohols And polylactone polyols.

  Moreover, alcohol components other than the said polyhydric alcohol can also be used. The alcohol component is not particularly limited, and examples thereof include monoalcohols such as methanol, ethanol, propyl alcohol, butyl alcohol, stearyl alcohol, and 2-phenoxyethanol; propylene oxide, butylene oxide, “Cardura E10” (trade name, HEXION Specialty) Examples include alcohol compounds obtained by reacting monoepoxy compounds such as Chemicals, Inc. (glycidyl esters of synthetic highly branched saturated fatty acids) and acids.

  The manufacturing method of a hydroxyl-containing polyester resin is not specifically limited, It can carry out in accordance with a normal method. For example, the acid component and the alcohol component are heated in a nitrogen stream at about 150 to 250 ° C. for about 5 to 10 hours, and a method of performing esterification reaction or transesterification reaction of the acid component and alcohol component is performed. A containing polyester resin can be produced.

  When the acid component and the alcohol component are esterified or transesterified, they may be added to the reaction vessel at one time, or one or both may be added in several portions. . Moreover, after synthesizing a hydroxyl group-containing polyester resin, the resulting hydroxyl group-containing polyester resin may be reacted with an acid anhydride to be half-esterified to obtain a carboxyl group- and hydroxyl group-containing polyester resin. Moreover, after synthesizing a carboxyl group-containing polyester resin, the above alcohol component may be added to obtain a hydroxyl group-containing polyester resin.

  In the esterification or transesterification reaction, as a catalyst for promoting the reaction, dibutyltin oxide, antimony trioxide, zinc acetate, manganese acetate, cobalt acetate, calcium acetate, lead acetate, tetrabutyl titanate, tetraisopropyl A catalyst known per se, such as titanate, can be used.

  The hydroxyl group-containing polyester resin can be modified with a fatty acid, a monoepoxy compound, a polyisocyanate compound or the like during or after the preparation of the resin.

  Examples of the fatty acid include coconut oil fatty acid, cottonseed oil fatty acid, hemp seed oil fatty acid, rice bran oil fatty acid, fish oil fatty acid, tall oil fatty acid, soybean oil fatty acid, linseed oil fatty acid, tung oil fatty acid, rapeseed oil fatty acid, castor oil fatty acid, dehydrated castor Oil fatty acid, safflower oil fatty acid and the like can be mentioned, and as the above-mentioned monoepoxy compound, for example, “Cardura E10” (trade name, manufactured by HEXION Specialty Chemicals, glycidyl ester of synthetic highly branched saturated fatty acid) is preferably used. it can.

  Examples of the polyisocyanate compound include aliphatic diisocyanates such as lysine diisocyanate, hexamethylene diisocyanate, and trimethylhexane diisocyanate; hydrogenated xylylene diisocyanate, isophorone diisocyanate, methylcyclohexane-2,4-diisocyanate, and methylcyclohexane-2. , 6-diisocyanate, 4,4′-methylenebis (cyclohexyl isocyanate), alicyclic diisocyanates such as 1,3- (isocyanatomethyl) cyclohexane; aromatic diisocyanates such as tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate Organic polyisocyanates such as polyisocyanates having 3 or more valences such as lysine triisocyanate An adduct of each of these organic polyisocyanates with a polyhydric alcohol, a low molecular weight polyester resin, water, etc .; a cyclized polymer (for example, isocyanurate) of each of these organic polyisocyanates, a biuret type adduct Etc. These polyisocyanate compounds can be used alone or in admixture of two or more.

  In addition, as the hydroxyl group-containing polyester resin, from the viewpoint of excellent smoothness and water resistance of the resulting coating film, the content of the alicyclic polybasic acid in the raw acid component is based on the total amount of the acid component. What is about 20-100 mol% is preferable, What is about 25-95 mol% is more preferable, What is about 30-90 mol% is still more preferable. In particular, the alicyclic polybasic acid is preferably 1,2-cyclohexanedicarboxylic acid and / or 1,2-cyclohexanedicarboxylic anhydride from the viewpoint of excellent smoothness of the resulting coating film.

  The hydroxyl group-containing polyester resin preferably has a hydroxyl value of about 1 to 200 mgKOH / g, more preferably about 2 to 180 mgKOH / g, and still more preferably about 5 to 170 mgKOH / g. Further, when the hydroxyl group-containing polyester resin further has a carboxyl group, the acid value thereof is preferably about 5 to 150 mgKOH / g, more preferably about 10 to 100 mgKOH / g, and 15 to 80 mgKOH / g. More preferably, it is about. The number average molecular weight of the hydroxyl group-containing polyester resin is preferably about 500 to 50,000, more preferably about 1,000 to 30,000, and about 1,200 to 10,000. Is more preferable.

Curing Agent The curing agent used as necessary is a compound that can cure the aqueous coating composition of the present invention by reacting with a functional group such as a hydroxyl group, a carboxyl group, and an epoxy group in the film-forming resin. . Examples of the curing agent include amino resins, polyisocyanate compounds, blocked polyisocyanate compounds, epoxy group-containing compounds, carboxyl group-containing compounds, carbodiimide group-containing compounds, and the like. Of these, amino resins that can react with hydroxyl groups, blocked polyisocyanate compounds, and carbodiimide group-containing compounds that can react with carboxyl groups are preferred, and amino resins are particularly preferred. A hardening | curing agent can be used individually or in combination of 2 or more types.

As said amino resin, the partial methylolation amino resin obtained by reaction of an amino component and an aldehyde component, or a complete methylolation amino resin can be used. Examples of the amino component include melamine, urea, benzoguanamine, acetoguanamine, steroguanamine, spiroguanamine, dicyandiamide and the like. Examples of the aldehyde component include formaldehyde, paraformaldehyde, acetaldehyde, and benzaldehyde.
Moreover, what methylated the methylol group of the said methylolated amino resin partially or completely with suitable alcohol can also be used. Examples of the alcohol used for etherification include methyl alcohol, ethyl alcohol, n-propyl alcohol, i-propyl alcohol, n-butyl alcohol, i-butyl alcohol, 2-ethylbutanol, 2-ethylhexanol and the like. .

  As the amino resin, a melamine resin is preferable. In particular, methyl ether melamine resins in which methylol groups of partially or fully methylolated melamine resins are partially or completely etherified with methyl alcohol, methylol groups of partially or fully methylolated melamine resins are partially or completely with butyl alcohol. Preferred is a methyl-butyl mixed etherified melamine resin in which the methylol group of a partially or completely methylolated melamine resin is partially or completely etherified with methyl alcohol and butyl alcohol. Etherified melamine resins are more preferred.

  The melamine resin preferably has a weight average molecular weight of about 400 to 6,000, more preferably about 800 to 5,000, and still more preferably about 1,000 to 4,000. Most preferably, it is about 1,200 to 3,000.

  A commercially available product can be used as the melamine resin. Examples of commercially available product names include “Cymel 202”, “Cymel 203”, “Cymel 238”, “Cymel 251”, “Cymel 303”, “Cymel 323”, “Cymel 324”, “Cymel 325”, “Cymel 327”, “Cymel 350”, “Cymel 385”, “Cymel 1156”, “Cymel 1158”, “Cymel 1116”, “Cymel 1130” (above, made by Nippon Cytec Industries, Inc.), “Uban 120”, “ “Uban 20HS”, “Uban 20SE60”, “Uban 2021”, “Uban 2028”, “Uban 28-60” (manufactured by Mitsui Chemicals, Inc.), and the like.

  The aqueous coating composition of the present invention uses a hydroxyl group-containing acrylic resin such as a core-shell type water-dispersible hydroxyl group-containing acrylic resin as a film-forming resin, and has a weight average molecular weight of 1, as a curing agent. It is preferable to use a melamine resin of about 000 to 4,000, particularly about 1,200 to 3,000, from the viewpoint of excellent glossiness (flip-flop properties) and water resistance of the resulting coating film.

  When a melamine resin is used as a curing agent, sulfonic acids such as paratoluenesulfonic acid, dodecylbenzenesulfonic acid, dinonylnaphthalenesulfonic acid; monobutyl phosphoric acid, dibutyl phosphoric acid, mono 2-ethylhexyl phosphoric acid, di-2- Alkyl phosphate esters such as ethylhexyl phosphate; salts of these acids with amine compounds, etc. can be used as catalysts.

  The blocked polyisocyanate compound is a compound obtained by blocking an isocyanate group of a polyisocyanate compound having at least two isocyanate groups in one molecule with a blocking agent. Examples of the blocking agent include oximes, phenols, alcohols, lactams, mercaptans, and the like.

  Examples of the polyisocyanate compound having at least two isocyanate groups in one molecule include aliphatic diisocyanates such as hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, dimer acid diisocyanate, and lysine diisocyanate; hydrogenated xylylene diisocyanate, cyclohexane. Cycloaliphatic diisocyanates such as silylene diisocyanate and isophorone diisocyanate; aromatic diisocyanates such as tolylene diisocyanate, phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, naphthalene diisocyanate; 2-isocyanate Natoethyl-2,6-diisocyanatocaproate, 3 Trivalent or higher organic polyisocyanate compounds such as isocyanatomethyl-1,6-hexamethylene diisocyanate and 4-isocyanatomethyl-1,8-octamethylene diisocyanate (common name: triaminononane triisocyanate); these polyisocyanate compounds And dimers or trimers of the following: a prepolymer obtained by subjecting these polyisocyanate compound and polyhydric alcohol, low molecular weight polyester resin or water to a urethanization reaction under an excess of isocyanate groups.

  As said carbodiimide group containing compound, what made the carbon dioxide reaction of the isocyanate groups of the said polyisocyanate compound can be used, for example. As the carbodiimide group-containing compound, it is preferable to use a polycarbodiimide compound having at least two carbodiimide groups in one molecule.

  As said polycarbodiimide compound, it is preferable to use a water-soluble or water-dispersible polycarbodiimide compound from viewpoints, such as smoothness of the coating film obtained. As the water-soluble or water-dispersible polycarbodiimide compound, any polycarbodiimide compound that can be stably dissolved or dispersed in an aqueous medium can be used without particular limitation.

  Specific examples of the water-soluble polycarbodiimide compound include “Carbodilite SV-02”, “Carbodilite V-02”, “Carbodilite V-02-L2”, and “Carbodilite V-04” (all manufactured by Nisshinbo Co., Ltd.). , Product name), etc. can be used. Moreover, as said water dispersible polycarbodiimide compound, "Carbodilite E-01", "Carbodilite E-02" (all are the Nisshinbo Co., Ltd. make, brand name) etc. can be used, for example.

  The said polycarbodiimide compound can be used individually or in combination of 2 or more types, respectively.

  In the water-based coating composition according to the present invention, the blending ratio of the film-forming resin and the curing agent is from 30 to 95 based on the total amount of both from the viewpoint of improving the smoothness and water resistance of the coating film. About 50% by mass, preferably about 50 to 90% by mass, more preferably about 60 to 80% by mass, the latter being about 5 to 70% by mass, preferably about 10 to 50% by mass, more preferably 20 to 40% by mass. It is preferable that it is about.

  When the aqueous coating composition according to the present invention contains a hydroxyl group-containing acrylic resin, the amount of the hydroxyl group-containing acrylic resin is preferably about 2 to 70% by mass based on the solid content in the aqueous coating composition. 10 to 55% by mass is more preferable, and about 20 to 45% by mass is even more preferable.

When the aqueous coating composition according to the present invention contains a hydroxyl group-containing polyester resin, the amount of the hydroxyl group-containing polyester resin is about 2 to 70% by mass based on the solid content in the aqueous coating composition. Preferably, it is about 10-55 mass%, More preferably, it is about 20-45 mass%.

  The aqueous medium can be appropriately selected from the aqueous media described in the description of the aqueous pigment dispersion of the present invention.

  The aqueous coating composition of the present invention preferably contains a hydrophobic medium. The hydrophobic medium used as necessary is an organic solvent having a mass dissolved in 100 g of water at 20 ° C. of 10 g or less, preferably 5 g or less, more preferably 1 g or less, such as rubber volatile oil, mineral Hydrocarbon solvents such as spirit, toluol, xylol, solvent naphtha; n-hexanol, n-octanol, 2-octanol, 2-ethylhexanol, n-decanol, benzyl alcohol, ethylene glycol 2-ethylhexyl ether, propylene glycol n- Ester solvents such as butyl ether, dipropylene glycol n-butyl ether, tripropylene glycol n-butyl ether, propylene glycol 2-ethylhexyl ether, propi; methyl isobutyl ketone, cyclohexanone, ethyl - amyl, there may be mentioned ketone solvents such as diisobutyl ketone, which may be used either alone or in combination of two or more.

  When the aqueous coating composition of the present invention contains a hydrophobic medium, the amount of the hydrophobic medium is the total resin solid content of the copolymer (A), the hydroxyl group-containing resin (B), and the melamine resin (C). It is preferable that the amount is in the range of usually 10 to 100 parts by mass, particularly 20 to 80 parts by mass, more particularly 30 to 60 parts by mass, based on the mass part.

  As the hydrophobic medium, an alcohol-based hydrophobic solvent is preferably used from the viewpoint of the sharpness of the formed coating film. Among them, alcohol-based hydrophobic solvents having 7 to 14 carbon atoms, preferably n-octanol, 2-octanol, 2-ethyl-1-hexanol, ethylene glycol 2-ethylhexyl ether, propylene glycol n-butyl ether and dipropylene glycol n -At least one alcoholic hydrophobic solvent selected from the group consisting of butyl ether is particularly preferred.

When the polyisocyanate compound which may be blocked as a curing agent is used as the curing catalyst, organometallic catalysts such as dibutyltin diacetate, dibutyltin dioctate and dibutyltin dilaurate; amines such as triethylamine and diethanolamine In the case of using an amino resin such as a melamine resin as a curing agent, a sulfonic acid compound such as paratoluenesulfonic acid, dodecylbenzenesulfonic acid, dinonylnaphthalenesulfonic acid, or a sulfonic acid thereof. An amine neutralized product of the compound can be preferably used.

  Examples of the ultraviolet absorber include benzophenone-based, benzotriazole-based, cyanoacrylate-based, salicylate-based, and oxalic acid anilide-based compounds.

  Examples of the ultraviolet stabilizer include hindered amine compounds.

  The substrate to which the water-based coating composition of the present invention can be applied is not particularly limited. For example, iron, aluminum, brass, copper plate, stainless steel plate, tin plate, galvanized steel plate, alloyed zinc (Zn- Al, Zn-Ni, Zn-Fe, etc.) Metal materials such as plated steel sheets; polyethylene resin, polypropylene resin, acrylonitrile-butadiene-styrene (ABS) resin, polyamide resin, acrylic resin, vinylidene chloride resin, polycarbonate resin, polyurethane resin, Resins such as epoxy resins and various plastic materials such as FRP; inorganic materials such as glass, cement and concrete; wood; fiber materials (paper, cloth, etc.), among others, metal materials and plastic materials Is preferred.

  In addition, the article to which the water-based coating composition of the present invention can be applied is not particularly limited, but includes an outer plate part of an automobile body such as a passenger car, a truck, a motorcycle, and a bus; an automobile part; a mobile phone, an audio device, and the like. An outer plate portion of a household electric product can be used, and among them, an outer plate portion of an automobile body and an automobile part are preferable.

  Further, the object to be coated may be one in which a surface treatment such as a phosphate treatment, a chromate treatment or a complex oxide treatment is performed on a metal surface such as the metal material or a vehicle body formed from the metal material. Furthermore, the object to be coated may be one in which an undercoat film and / or an intermediate coat film such as various electrodeposition paints are formed on the metal base material or the vehicle body.

  The coating method of the aqueous coating composition of the present invention is not particularly limited, and examples thereof include air spray coating, airless spray coating, rotary atomization coating, curtain coat coating, and the like. A film can be formed. These coating methods may be electrostatically applied as necessary. Of these, air spray coating and rotary atomization coating are preferred. The coating amount of the water-based coating composition is usually 5 to 70 μm, preferably about 10 to 50 μm as a cured film thickness.

  The wet coating film is cured by applying the aqueous coating composition of the present invention to an object to be coated and then heating. Heating can be performed by a heating means known per se. For example, a drying furnace such as a hot air furnace, an electric furnace, or an infrared induction heating furnace can be used. The heating temperature is usually within the range of about 80 to about 180 ° C, preferably about 100 to about 170 ° C, more preferably about 120 to about 160 ° C. The heating time is not particularly limited, but is usually 10 to 40 minutes, preferably about 15 to 30 minutes.

  The aqueous paint composition of the present invention can be used as a colored paint composition (including metallic paint and interference color paint) in which various pigments such as a color pigment, a metallic pigment, and an interference color pigment are blended. Among them, it can be suitably used as a paint for automobiles. As an aqueous base coat paint in a coating method in which a water-based base coat paint containing a glitter pigment and / or a color pigment is applied on an object to be coated, and then a clear paint is applied. It can be preferably used.

  When the aqueous coating composition of the present invention is used as an aqueous base coat coating, for example, the aqueous coating composition of the present invention is applied on a coating object that has been subjected to electrodeposition coating and / or intermediate coating to form a coating. Without coating the film, a clear coating is applied on the uncured coating, and then the uncured coating and the clear coating are heated and cured at the same time to form a multi-layer coating. It can be shown. The uncured coating includes a touch-dried coating and a semi-cured drying coating.

  When the aqueous coating composition of the present invention is applied by a 2-coat 1-bake method, the aqueous coating composition has a cured film thickness of usually 5 to 40 μm, preferably 10 to 30 μm, more preferably 10 to 20 μm. The clear coating can be applied so that the cured film thickness is usually in the range of 10 to 80 μm, preferably 15 to 60 μm.

  Moreover, when forming a multilayer coating film by said 2 coat 1 baking system, from a viewpoint of preventing generation | occurrence | production of coating-film defects, such as a repellency, a coating film is substantially after the application of the aqueous coating composition of this invention. It is preferable to perform preheating (preliminary heating), air blowing, etc. under heating conditions that do not harden. The preheating can be performed usually at a temperature of about 40 to about 100 ° C, preferably about 50 to about 90 ° C, more preferably about 60 to about 80 ° C, and the preheating time is usually 30 seconds to 15 minutes, Preferably it is 1-10 minutes, More preferably, it can be about 2-5 minutes. The air blow can be usually performed by blowing air heated to a normal temperature or a temperature of about 25 to about 80 ° C. on the coated surface of the object to be coated. In addition, after application of the clear paint, an interval of about 1 to 60 minutes, preferably about 3 to 20 minutes at room temperature, or a preheating at a temperature of about 40 to about 80 ° C. for about 1 to 60 minutes, if necessary. The coating can then be heat cured.

  The aqueous coating composition and the clear coating can be carried out by the above-mentioned heating means known per se, usually about 80 to about 180 ° C., preferably about 100 to about 170 ° C., more preferably about 120 to about 160 ° C. It is suitable to heat both coatings at the same temperature for 10 to 40 minutes, preferably 15 to 30 minutes.

  Further, the water-based coating composition of the present invention comprises applying an intermediate coating on an object to be coated, applying a base coating on the uncured intermediate coating without curing the coating, By a 3-coat 1-bake method in which a clear coating is applied on the uncured base coat without curing the coating, and three layers of the intermediate coating, base coating and clear coating are heated and cured simultaneously. In the multilayer coating film forming method, it can be suitably used as an intermediate coating material and / or a base coating material.

  When the aqueous coating composition of the present invention is applied by the above-mentioned three-coat one-bake method, the intermediate coating is preferably applied so that the cured film thickness is usually in the range of 10 to 60 μm, preferably 20 to 40 μm. The base coat paint is preferably applied so that the cured film thickness is usually in the range of 5 to 40 μm, preferably 10 to 30 μm, more preferably 10 to 20 μm, and the clear paint is a cured film thickness. In general, it is preferable that the coating is performed so as to be within a range of 10 to 80 μm, preferably 15 to 60 μm.

  In addition, when the aqueous coating composition of the present invention is used as an intermediate coating and / or base coating, preheating (preheating) under heating conditions in which the coating film is not substantially cured after application of the aqueous coating composition, It is preferable to perform air blow or the like. The preheating can be performed usually at a temperature of about 40 to about 100 ° C, preferably about 50 to about 90 ° C, more preferably about 60 to about 80 ° C, and the preheating time is usually 30 seconds to 15 minutes, Preferably it is 1-10 minutes, More preferably, it can be about 2-5 minutes. The air blow can be usually performed by blowing air heated to a normal temperature or a temperature of about 25 to about 80 ° C. on the coated surface of the object to be coated. In addition, after the application of the clear paint, an interval of 1 to 60 minutes, preferably 3 to 20 minutes is provided at room temperature as necessary, or preheating is performed at a temperature of about 40 to about 80 ° C. for about 1 to 60 minutes. The coating can then be heat cured.

  Curing of the coating film can be carried out by the above-mentioned heating means known per se, usually at a temperature of about 80 to about 180 ° C., preferably about 100 to about 170 ° C., more preferably about 120 to about 160 ° C. It is suitable to cure the three-layer coating film simultaneously by heating for about 40 minutes, preferably about 15-30 minutes.

  By using the aqueous coating composition of the present invention, a coating film excellent in coating film performance and appearance can be formed. Therefore, the aqueous coating composition of the present invention can be suitably used as an automotive coating material.

  When the aqueous coating composition of the present invention is used as an intermediate coating, a thermosetting base coating known per se can be used as the base coating, specifically, for example, an alkyd resin, a polyester resin, A coating material containing a base resin such as an acrylic resin or a urethane resin and a curing agent such as an amino resin, a polyisocyanate compound, a block polyisocyanate compound, or a carbodiimide group-containing compound can be used. As the base coat paint, from the viewpoint of environmental problems, resource saving, etc., a high solid type paint or water-based paint with a small amount of organic solvent used can be suitably used.

  When the aqueous paint composition of the present invention is used as a base coat paint, a known thermosetting intermediate coat paint can be used as the intermediate coat paint. Specifically, for example, an alkyd resin or a polyester resin can be used. A coating material comprising a base resin such as an acrylic resin or a urethane resin and a curing agent such as an amino resin, a polyisocyanate compound, a block polyisocyanate compound, or a carbodiimide group-containing compound can be used. As the intermediate coating material, from the viewpoint of environmental problems and resource saving, a high solid type coating material, a water-based coating material, a powder coating material, etc. with a small amount of organic solvent used can be suitably used.

  In addition, as the clear paint, for example, a known paint that is usually used in the painting of automobile bodies can be used. Specifically, a base resin such as an acrylic resin, a polyester resin, an alkyd resin, a urethane resin, an epoxy resin, or a fluororesin having a crosslinkable functional group such as a hydroxyl group, a carboxyl group, an epoxy group, or a silanol group, and a melamine resin, Urea resin, optionally blocked polyisocyanate compound, carboxyl group-containing compound or resin, epoxy group-containing compound or resin-containing organic solvent-based thermosetting paint, aqueous thermosetting paint, Examples thereof include thermosetting powder coatings. Among these, a thermosetting paint containing a carboxyl group-containing resin and an epoxy group-containing resin and a thermosetting paint containing a hydroxyl group-containing resin and a polyisocyanate compound which may be blocked are suitable.

  Further, the form of the clear coating composition is not particularly limited, and may be any form such as an organic solvent type, a non-aqueous dispersion type, an aqueous solution type, an aqueous dispersion (slurry) type, a high solid type, and a powder type. Can be used.

  If necessary, the clear paint may contain coloring pigments, glitter pigments, dyes and the like to such an extent that the transparency of the formed coating film is not hindered. An agent, a light stabilizer, an antifoaming agent, a thickener, a rust inhibitor, a plasticizer, an organic solvent, a surface conditioner, an anti-settling agent and the like can be appropriately contained.

Hereinafter, the present invention will be described more specifically with reference to examples. The scope of the present invention is not limited to these examples. Further, “parts” and “%” in the examples represent “parts by mass” and “% by mass”, respectively, unless otherwise specified. Moreover, the film thickness of a coating film is based on a cured coating film.
Resin for pigment dispersion:
Synthesis of monomer component (a) Production Example 1
77.6 parts of 2-methacryloyloxyethyl isocyanate and 0.07 part of p-methoxyphenol were added to a four-necked reaction vessel equipped with a thermometer, a thermostat, a stirrer, a reflux condenser, an air introduction tube and a dropping device. . Next, 66.6 parts of N, N-dimethylaminoethoxyethanol was added dropwise over 1 hour while agitating dry air in the reaction vessel and keeping the temperature at 30 ° C. or lower while stirring. After completion of dropping, the mixture was aged by stirring at 30 ° C. for 2 hours to obtain a polymerizable unsaturated monomer (a1) having an active ingredient of 100%. The monomer is a monomer in which, in the general formula (1), X is the general formula (2), Y is a methylene group, and p = 1.
Production Example 2
77.6 parts of 2-methacryloyloxyethyl isocyanate and 0.08 part of p-methoxyphenol were added to a four-necked reaction vessel equipped with a thermometer, a thermostat, a stirrer, a reflux condenser, an air introduction tube and a dropping device. . Next, 88.6 parts of N, N-dimethylaminoethoxyethoxyethanol was added dropwise over 1 hour while agitating dry air in the reaction vessel and keeping the temperature at 30 ° C. or lower while stirring. After completion of dropping, the mixture was aged by stirring at 30 ° C. for 2 hours to obtain a polymerizable unsaturated monomer (a2) having 100% of the active ingredient. The monomer is a monomer in which, in the general formula (1), X is the general formula (2), Y is a methylene group, and p = 2.

Production Example 3
To a four-necked reaction vessel equipped with a thermometer, thermostat, stirring device, reflux condenser, air inlet tube, and dropping device, add 59.6 parts of 2-methacryloyloxyethoxyethyl isocyanate and 0.05 parts of p-methoxyphenol. It was. Next, 44.5 parts of N, N-dimethylaminoethanol was added dropwise over 1 hour while agitating dry air in the reaction vessel and keeping the temperature at 30 ° C. or lower while stirring. After completion of dropping, the mixture was aged by stirring at 30 ° C. for 2 hours to obtain a polymerizable unsaturated monomer (a3) having 100% active ingredient. In the general formula (1), X is the general formula (2), Y is an oxyethylene group of the repeating unit 1, and p = 0.
Production Example 4
To a four-necked reaction vessel equipped with a thermometer, thermostat, stirring device, reflux condenser, air inlet tube, and dropping device, add 59.6 parts of 2-methacryloyloxyethoxyethyl isocyanate and 0.05 parts of p-methoxyphenol. It was. Next, 88.6 parts of N, N-dimethylaminoethoxyethanol was added dropwise over 1 hour while agitating dry air in the reaction vessel and keeping the temperature at 30 ° C. or lower while stirring. After completion of dropping, the mixture was aged by stirring at 30 ° C. for 2 hours to obtain a polymerizable unsaturated monomer (a4) having 100% of the active ingredient. In the general formula (1), the monomer is a monomer in which X is the general formula (2), Y is an oxyethylene group of the repeating unit 1, and p = 1.
Production Example 5
To a four-necked reaction vessel equipped with a thermometer, thermostat, stirrer and air inlet tube was added 252 parts of methyl methacrylate, 146.5 parts of N, N-dimethylaminoethoxyethanol and 3.30 parts of phenothiazine, and the mixture was The reaction was carried out at 95 degrees for 1 hour with stirring. Next, the reaction mixture was cooled to 90 ° C., 1.73 parts of di-n-butyltin oxide was added, and the mixture was reacted at 90 to 115 ° C. for 6 hours. Meanwhile, the reaction was carried out while removing the azeotrope. After the reaction, the pressure in the reactor was gradually reduced to obtain a polymerizable unsaturated monomer (a5) having an active ingredient of 100%. In the general formula (1), X is the general formula (3) and q = 0.
Production Example 6
In a four-necked reaction vessel equipped with a thermometer, thermostat, stirring device, reflux condenser, air inlet tube and dropping device, 252 parts of methyl methacrylate, 195.0 parts of N, N-dimethylaminoethoxyethoxyethanol and phenothiazine 4 .39 parts was added and the mixture was allowed to react at 95 degrees for 1 hour with stirring. Next, the reaction mixture was cooled to 90 ° C., 1.73 parts of di-n-butyltin oxide was added, and the mixture was reacted at 90 to 115 ° C. for 6 hours. Meanwhile, the reaction was carried out while removing the azeotrope. After the reaction, the pressure in the reactor was gradually reduced to obtain a polymerizable unsaturated monomer (a6) having an active ingredient of 100%. In the general formula (1), X is the general formula (3), and the monomer is q = 1.
Production Example 7
To a reaction vessel equipped with a thermometer, thermostat, stirring device, reflux condenser, air introduction tube, drying tube and dropping device, add 111.2 parts of 2-hydroxyethyl methacrylate and 0.11 part of p-methoxyphenol and dry. The temperature was raised to 60 ° C. while introducing air at 20 mL per minute. Next, while maintaining 60 ° C., 71.6 parts of isophorone diisocyanate was added dropwise over 1 hour while stirring and introducing dry air. After completion of the dropwise addition, the mixture was aged by stirring at 60 ° C. for 2 hours. . Next, the temperature was raised to 80 ° C., and the mixture was further aged at the same temperature for 1 hour for aging. Next, the temperature was lowered to room temperature, and 44.5 parts of N, N-dimethylaminoethoxyethanol was added dropwise over 1 hour while stirring at 30 ° C. or lower. After completion of the dropwise addition, the mixture was aged at room temperature for 2 hours to obtain a polymerizable unsaturated monomer (a7) having an active ingredient of 100%. In the general formula (1), X is the general formula (4), and Z is a monomer of an oxyethylene group of the repeating unit 1.
Production Example 8
77.6 parts of 2-methacryloyloxyethyl isocyanate and 0.06 parts of p-methoxyphenol were added to a four-necked reaction vessel equipped with a thermometer, a thermostat, a stirrer, a reflux condenser, an air introduction tube and a dropping device. . Next, 44.5 parts of N, N-dimethylaminoethanol was added dropwise over 1 hour while agitating dry air in the reaction vessel and keeping the temperature at 30 ° C. or lower while stirring. After completion of dropping, the mixture was aged at 30 ° C. for 2 hours to obtain a polymerizable unsaturated monomer (a8) having an active ingredient of 100%. In the general formula (1), X is the general formula (2), Y is a methylene group, and p = 0.

Production of pigment dispersion resin Example 1
In a reaction vessel equipped with a thermometer, thermostat, stirrer, reflux condenser and dropping device, 15 parts of propylene glycol monomethyl ether and 25 parts of propylene glycol monobutyl ether were charged, heated and stirred, and maintained at 110 ° C. Among them, 18.4 parts of the monomer (a1) obtained in Production Example 1, “NF biisomer S20W” (trade name, manufactured by Degussa, R ³ in the general formula (5) is a methyl group, and R ⁴ is a methyl group. A 50% water-diluted product of methoxypolyethylene glycol monomethacrylate having an ethylene group, R ⁵ of ethylene, m of 45 and a molecular weight of about 2,000.) 20 parts, 10 parts of 2-hydroxyethyl acrylate, 25 parts of methyl methacrylate. A mixture consisting of 8 parts, 25.8 parts of n-butyl acrylate, 1 part of azobisisobutyronitrile and 20 parts of propylene glycol monomethyl ether was added dropwise over 3 hours. After completion of the dropwise addition, the mixture was aged at 110 ° C. for 30 minutes, and then an additional catalyst mixture composed of 15 parts of propylene glycol monomethyl ether and 0.5 part of azobisisobutyronitrile was added dropwise over 1 hour. The mixture was further aged at 110 ° C. for 1 hour and then cooled to obtain a pigment dispersion resin (A1) having a solid content of 50%.
Examples 2-14, Comparative Examples 1-3
In Example 1, except that the component composition and blending ratio are as shown in Table 1 below, the pigment-dispersing resins (A2) to (A14) and (AC1) to (AC3) were prepared in the same manner as in Example 1. Obtained. The solid content, amine value, hydroxyl value, and weight average molecular weight of the obtained pigment dispersing resin are shown in Table 1 below. In addition, the amount of each polymerizable unsaturated monomer in the following Table 1 is a solid content.

(Note 1) MPEG1000: Trade name, manufactured by Degussa, R ³ in the general formula (5) is a methyl group, R ⁴ is a methyl group, R ⁵ is an ethylene group, m is 21, and the molecular weight is about 1,000. Methoxypolyethylene glycol monomethacrylate that is above.
(Note 2) Dimethylaminoethyl methacrylate (Note 3) Dimethylaminopropyl acrylate
Aqueous pigment dispersion:
Production Example 15 of aqueous pigment dispersion
In a stirring and mixing container, 200 parts of pigment dispersing resin (A1) obtained in Example 1 (100 parts of solid content), 60 parts of “Raven5000UIII” (trade name, carbon black pigment manufactured by Columbian Carbon) and deionized water 750 parts were added and mixed uniformly. Next, the obtained mixed liquid was put in a wide-mouth glass bottle having a capacity of 225 cc, and zirconia beads having a diameter of about 0.5 mmφ were added as a dispersion medium and sealed, and dispersed in a paint shaker for 5 hours to form an aqueous pigment dispersion (B1). Got.

Examples 16 to 34, Comparative Examples 4 to 8
In Example 15, aqueous pigment dispersions (B2) to (B20) and (BC1) to (BC5) were obtained in the same manner as in Example 15 except that the composition was as shown in Table 2 below.

(* 4) Cyanine Blue 5206: manufactured by Dainichi Seika Kogyo Co., Ltd., trade name, organic blue pigment (* 5) S # 12000: manufactured by Avicia, wetting and dispersing agent, trade name "Solsperse 12000"
(Note 6) RT355D: BASF Corporation organic red pigment, trade name “Shinkasha Magenta RT355D”
Performance test Each water pigment dispersion obtained in Examples 15 to 34 and Comparative Examples 4 to 8 was subjected to a performance test based on the following test method. The test results are shown in Table 2.

Test method
Sharpness (gloss): The gloss of a coating film obtained by applying a pigment dispersion on a transparent PET film to a cured film thickness of 25 μm and baking at 140 ° C. for 30 minutes is JIS K5400 7.6 (1990). According to the above, the 60-degree specular reflectance of each coating film was measured. Larger values indicate higher gloss and better clarity.

Color developability: “MA-68II” (trade name, manufactured by X-Rite, multi-angle spectrocolorimeter) was used for the coating film obtained as described in the above-described clearness (gloss) test. The film is irradiated with the standard light D65 from an angle of 45 ° with respect to the axis perpendicular to the measurement target surface, and the light in the direction perpendicular to the measurement target surface among the reflected light (at an angle of 45 ° with respect to the regular reflection light). L * value (L * 45) was measured for the light received at (1). For pigments other than black, the color developability was evaluated with a value of L * 45. For black pigment, in addition to the L * 45 value, the L * value (L * 25 and L * 75, respectively) when standard light D65 is irradiated from 25 ° and 75 ° angles is measured, and the sum of the three values It was evaluated with.
A lower value indicates better color developability.

Viscosity characteristics: In accordance with JIS-K-5400, with a digital display type rotational viscometer (manufactured by Brook Field, B-type viscometer), the viscosity (A) at 25 rpm and the viscosity at 60 rpm (B) was measured. Moreover, (A) / (B) was calculated and used as a thixotropy index value (TI value). It shows that the pigment dispersibility of the obtained aqueous pigment dispersion is so favorable that (A) and (B) are small. Moreover, the closer the TI value is to 1, the better the pigment dispersibility of the obtained aqueous pigment dispersion.

Water-based paint composition:
Synthesis of film-forming resin
Synthetic production example 9 of hydroxyl group-containing acrylic resin
A reaction vessel equipped with a thermometer, thermostat, stirrer, reflux condenser, nitrogen inlet tube and dropping device, 128 parts of deionized water, “ADEKA rear soap SR-1025” (trade name, manufactured by ADEKA, emulsifier, active ingredient 25 %) 2 parts were charged, stirred and mixed in a nitrogen stream, and heated to 80 ° C.

  Next, 1% of the total amount of the following monomer emulsion for core part and 5.3 parts of 6% ammonium persulfate aqueous solution were introduced into the reaction vessel and kept at 80 ° C. for 15 minutes. Thereafter, the remainder of the monomer emulsion for the core part was dropped into a reaction vessel maintained at the same temperature over 3 hours, and aging was performed for 1 hour after completion of the dropping. Next, the following monomer emulsion for shell part was added dropwise over 1 hour, and after aging for 1 hour, it was cooled to 30 ° C. while gradually adding 40 parts of 5% 2- (dimethylamino) ethanol aqueous solution to the reaction vessel, The mixture was discharged while being filtered through a 100 mesh nylon cloth to obtain a hydroxyl group-containing acrylic resin (C1) having an average particle size of 100 nm, a solid content of 30%, an acid value of 33 mgKOH / g, and a hydroxyl value of 25 mgKOH / g.

  Monomer emulsion for core part: 40 parts of deionized water, 2.8 parts of “ADEKA rear soap SR-1025”, 2.1 parts of methylenebisacrylamide, 2.8 parts of styrene, 16.1 parts of methyl methacrylate, 28 of ethyl acrylate The monomer emulsion for the core part was obtained by mixing and stirring the part and 21 parts of n-butyl acrylate.

  Monomer emulsion for shell part: 17 parts of deionized water, 1.2 parts of “ADEKA rear soap SR-1025”, 0.03 part of ammonium persulfate, 3 parts of styrene, 5.1 parts of 2-hydroxyethyl acrylate, 5 parts of methacrylic acid .1 part, 6 parts of methyl methacrylate, 1.8 parts of ethyl acrylate and 9 parts of n-butyl acrylate were mixed and stirred to obtain a monomer emulsion for shell part.

Production and production example 10 of hydroxyl group-containing polyester resin
In a reaction vessel equipped with a thermometer, thermostat, stirrer, reflux condenser and water separator, 109 parts of trimethylolpropane, 141 parts of 1,6-hexanediol, 126 parts of 1,2-cyclohexanedicarboxylic acid anhydride and adipine 120 parts of acid was charged, and the temperature was raised from 160 ° C. to 230 ° C. over 3 hours, followed by a condensation reaction at 230 ° C. for 4 hours. Subsequently, in order to introduce a carboxyl group into the obtained condensation reaction product, 38.3 parts of trimellitic anhydride was added and reacted at 170 ° C. for 30 minutes, and then 2-ethyl-1-hexanol (20 Diluted with 100 g of water at 0.1 ° C. at a temperature of 0.1 g), a hydroxyl group-containing polyester resin solution having a solid content of 70%, an acid value of 46 mgKOH / g, a hydroxyl value of 150 mgKOH / g, and a number average molecular weight of 1,400 (D1) was obtained.

Production of aqueous coating composition Example 35
In a stirring and mixing container, 84.2 parts of the aqueous pigment dispersion (B1) obtained in Example 15, 168 parts of the hydroxyl group-containing acrylic resin (C1) obtained in Production Example 9, and the hydroxyl group-containing polyester resin obtained in Production Example 10 ( D1) 26.2 parts, melamine resin (E1) (methyl-butyl mixed etherified melamine resin, solid content 60%, weight average molecular weight 2,000) 41.7 parts, and uniformly mixed. Primal ASE-60 "(trade name, manufactured by Rohm and Haas, polyacrylic acid thickener), 2- (dimethylamino) ethanol and deionized water were added to adjust the pH to 8.0, solid content of 24% at 20 ° C. Ford Cup No. An aqueous coating composition (X1) having a viscosity of 50 according to 4 was obtained.

Examples 36-54 and Comparative Examples 9-13
In Example 35, the Ford Cup No. at pH 8.0, solid content of 25%, 20 ° C. was prepared in the same manner as in Example 35 except that the formulation was as shown in Table 3 below. Water-based coating compositions (X2) to (X20) and (XC1) to (XC5) having a viscosity of 50 according to 4 were obtained.

  About each water-based paint obtained in the said Examples 35-54 and Comparative Examples 9-13, the performance test was done based on the following test method. The test results are shown in Table 3.

Method for preparing test coating Each water-based paint was applied on a transparent PET film so as to have a cured film thickness of 25 μm, allowed to stand at room temperature for 10 minutes, then preheated at 80 ° C. for 15 minutes, and then 140 A test coating was obtained by baking at 30 ° C. for 30 minutes.

Evaluation Test Each of the test plates was evaluated for sharpness and color development in the same manner as the pigment dispersion test method. The evaluation results are shown in Table 3 below.

Claims (8)

A resin for pigment dispersion, which is a copolymer of (a) a polymerizable unsaturated monomer having a cationic functional group represented by the general formula (1), and (b) another polymerizable unsaturated monomer.
General formula (1)

[Wherein, X represents a group represented by the following general formula (2) ~ (4), R 1 represents a hydrogen atom or a methyl group, ^{R 2} represents a methyl group]
General formula (2)

[Wherein Y represents an alkylene group or a polyoxyalkylene group having one or more repeating units. In addition, p represents an integer of 1 or more when Y is an alkylene group, and p represents an integer of 0 or more when Y is a polyoxyalkylene group having 1 or more repeating units. ]
General formula (3)

[Wherein q represents an integer of 0 or more]
General formula (4)

[Wherein Z represents a linear or branched alkyl chain or a polyoxyalkylene group having one or more repeating units. ] The resin for pigment dispersion according to claim 1, wherein the other polymerizable unsaturated monomer (b) contains a polymerizable unsaturated monomer (b1) having a polyoxyalkylene chain represented by the following general formula (5).

[Wherein, R ³ represents a hydrogen atom or a methyl group, R ⁴ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms which may be branched, and R ⁵ represents an alkyl group having 2 to 4 carbon atoms which may be branched. M represents an integer of 3 to 150, and the m oxyalkylene units (R ⁵ O) may be the same as or different from each other.]   The resin for pigment dispersion according to claim 1 or 2, wherein the other polymerizable unsaturated monomer (b) contains (b2) a hydroxyl group-containing polymerizable unsaturated monomer having no polyoxyalkylene chain. X polymerizable unsaturated monomer containing a cationic functional group represented by the general formula (1) (a) and, either 3 to p there is no claim 1 is 1 or 2 in the general formula (2) 1 The pigment dispersing resin described in the item. The resin for pigment dispersion according to any one of claims 1 to 4 , wherein the copolymer has a weight average molecular weight in the range of 500 to 100,000. An aqueous pigment dispersion containing the pigment dispersion resin according to any one of claims 1 to 5 , a pigment, and an aqueous medium. An aqueous coating composition containing the aqueous pigment dispersion according to claim 6 . An article coated with the aqueous coating composition according to claim 7 .