WO2023203867A1

WO2023203867A1 - Aqueous multi-component polyurethane coating composition

Info

Publication number: WO2023203867A1
Application number: PCT/JP2023/006572
Authority: WO
Inventors: 俊博木村; 安明西澤; 健介片岡
Original assignee: 関西ペイント株式会社
Priority date: 2022-04-22
Filing date: 2023-02-22
Publication date: 2023-10-26
Also published as: JP2023160702A; JP7235923B1

Abstract

The present invention addresses the problem of providing an aqueous multi-component polyurethane coating composition that enables polishing work of a coating film to be performed at a drying time equivalent to that of an organic solvent-type coating material, and has excellent water resistance, weather resistance, and finishing properties.　Provided are an aqueous multi-component polyurethane coating composition and a method for applying the same, the aqueous multi-component polyurethane coating composition comprising a first component (A) containing a hydroxy group-containing resin emulsion component (a1), a catalyst compound (a2), and water, and a second component (B) containing a polyisocyanate component (b1) and an organic solvent (b2), wherein: the glass transition temperature of the hydroxy group-containing resin contained in the hydroxy group-containing resin emulsion component (a1) is at least 40°C; when the composition is applied on a tin plate so as to form a coating film having a thickness of 40 μm after being dried, and the coating film is baked at 60°C for 20 minutes, the Martens hardness of the coating film is 10-70 N/mm2; and when the composition is applied so as to form a coating film having a thickness of 40 μm after being dried, and the coating film is baked at 60°C for 20 minutes, the acetone extraction coating residual percentage of the coating film is at least 70%.<sp />

Description

Water-based multi-component polyurethane coating composition

The present invention relates to an aqueous multi-component polyurethane coating composition and a coating method for applying the aqueous multi-component polyurethane coating composition.

Urethane paints are widely used in paint applications because they can form coatings with excellent physical properties that combine toughness and flexibility through urethane bonds.

Urethane paints include (1) low-temperature-curing two-component urethane paints, and (2) heat-curing one-component urethane paints.

(1) is a two-component paint with a base agent and a curing agent, and is a paint in which the base agent such as a polyol compound and a curing agent containing a polyisocyanate compound are mixed in a fixed proportion immediately before painting. In this paint, the polyisocyanate compound has high reactivity and the crosslinking reaction between hydroxyl groups and isocyanate groups easily proceeds, so the paint film can be cured even at room temperature. (2) is a one-component paint containing a blocked polyisocyanate whose reactivity is suppressed by masking the isocyanate groups with a blocking agent, a polyol compound, and the like. In this coating, it is necessary to regenerate the isocyanate groups by dissociating the blocking agent of the blocked polyisocyanate, so it is usually necessary to heat the coating film at a high temperature after coating.

Therefore, when the object to be painted is large, such as a building structure, or when there is a concern that the object may be deformed due to heating, such as (1) low-temperature curing two-component urethane paint is usually applied.

Furthermore, since automobile bodies are equipped with parts that are sensitive to high temperatures, such as gasoline tanks, electrical components, and computers, it is difficult to bake the repair coating at high temperatures when repainting completed automobile bodies. . For this reason, two-component urethane paints are often used in repair paint compositions for refinishing automobiles.

In recent years, environmental pollution and the impact on the human body have become more of a consideration, and the use of water-based paints that use water as the main solvent to replace organic solvent-based paints has increased significantly. There is a need for the development of aqueous compositions. On the other hand, since water-based paints take longer to dry than organic solvent-based paints, drying properties and/or finishing properties after application may be insufficient. In particular, when it is necessary to polish a cured coating film that has been formed, the coating must be sufficiently dried until it has a hardness suitable for polishing, and improvements in this need are needed.

Patent Document 1 discloses that in an aqueous two-component clear coating composition containing a base agent (I) containing an acrylic resin and a curing agent (II), the base agent (I) contains an acrylic resin (A1) having an acid value of less than 40 mgKOH/g. and an acrylic resin (A2) having an acid value within the range of 100 to 300 mgKOH/g, a polyisocyanate compound (B) having an acid group in the curing agent (II), and a glycol having no hydroxyl group. An aqueous two-component clear coating composition characterized by containing an ether organic solvent (C) is disclosed. The aqueous two-component clear paint composition described in Patent Document 1 has excellent drying properties, finishing properties, and painting workability, but the drying time until the paint film can be polished is shorter than that of organic solvent-based paints. However, it took a long time and there was also an issue with the water resistance of the paint film.

Japanese Patent Application Publication No. 2018-2900

The problem to be solved by the present invention is to provide an aqueous multi-component polyurethane coating composition that can polish a paint film in the same drying time as an organic solvent-based coating and has excellent water resistance, weather resistance, and finish quality. The goal is to provide the following.

As a result of intensive studies to solve the above problems, the inventors have developed a first component (A) containing a hydroxyl group-containing resin emulsion component (a1), a catalyst compound (a2) and water, a polyisocyanate component (b1) and An aqueous multi-component polyurethane coating composition containing a second component (B) containing an organic solvent (b2), wherein the glass transition temperature of the hydroxyl group-containing resin contained in the hydroxyl group-containing resin emulsion component (a1) is 40° C. or higher. The Martens hardness of the coating film is 10 N/mm ² or more and 70 N/mm ² or less, and the coating film is coated on a tin plate so that the film thickness after drying is 40 μm and baked at 60°C for 20 minutes, and the film thickness after drying is It has been discovered that the above problem can be solved by an aqueous multi-component polyurethane coating composition in which the acetone-extracted coating film residual rate of the coating film coated to a thickness of 40 μm and baked at 60° C. for 20 minutes is 70% or more, and the present invention has been achieved. I was able to complete it.

That is, the present invention provides the following aqueous multi-component polyurethane coating composition and a coating method for coating the aqueous multi-component polyurethane coating composition.
Item 1. A water-based resin emulsion containing a hydroxyl group-containing resin emulsion component (a1), a first component (A) containing a catalyst compound (a2) and water, and a second component (B) containing a polyisocyanate component (b1) and an organic solvent (b2). A multi-component polyurethane coating composition, wherein the hydroxyl group-containing resin contained in the hydroxyl group-containing resin emulsion component (a1) has a glass transition temperature of 40°C or higher, and is coated on a tin plate so that the film thickness after drying is 40 μm. The acetone coating film was baked at 60°C for 20 minutes and the Martens hardness was 10 N/mm ² or more and 70 N/mm ² or less, and the film thickness after drying was 40 μm. An aqueous multi-component polyurethane coating composition having an extracted coating film residual rate of 70% or more.
Item 2. 2. The aqueous multi-component polyurethane coating composition according to item 1, wherein the acetone-extracted coating film residual rate of a coating film coated to a dry film thickness of 40 μm and baked at 60° C. for 20 minutes is 95% or less.
Item 3. The aqueous multi-component type according to item 1 or 2, wherein the hydroxyl group-containing resin contained in the hydroxyl group-containing resin emulsion component (a1) has a hydroxyl value of 50 to 250 mgKOH/g and an acid value of 5 to 40 mgKOH/g. Polyurethane paint composition.
Item 4. The aqueous multi-component polyurethane coating composition according to any one of items 1 to 3 above, wherein the hydroxyl group-containing resin emulsion component (a1) contains a self-emulsifying emulsion.
Item 5. The hydroxyl group-containing resin contained in the hydroxyl group-containing resin emulsion component (a1) contains, as a part of its components, a hydroxyl group-containing polymerizable unsaturated compound, a carboxyl group-containing polymerizable unsaturated compound, and an epoxy group-containing polymerizable unsaturated compound. The aqueous multi-component polyurethane coating composition according to any one of items 1 to 4 above, which contains a hydroxyl group-containing acrylic resin (a1-1) as a copolymerization component.
Item 6. Item 5. The aqueous multi-component polyurethane coating composition according to item 5, wherein the hydroxyl group-containing acrylic resin (a1-1) has a molecular weight of 10,000 to 18,000.
Section 7. 7. The aqueous multi-component polyurethane coating composition according to any one of items 1 to 6 above, wherein the catalyst compound (a2) contains a molybdenum compound.
Section 8. Any one of items 1 to 7 above, wherein the content of the catalyst compound (a2) is within the range of 0.0001 to 0.1 part by mass based on 100 parts by mass of the resin solid content of the first component (A). The aqueous multi-component polyurethane coating composition described in 2.
Item 9. The second component (B) is at least one metal catalyst compound (d) selected from the group consisting of zinc compounds, tin compounds, zirconium compounds, bismuth compounds, lead compounds, cobalt compounds, manganese compounds, titanium compounds, and aluminum compounds. The aqueous multi-component polyurethane coating composition according to any one of items 1 to 8 above.
Item 10. Contains at least one metal catalyst compound (d) selected from the group consisting of zinc compounds, tin compounds, zirconium compounds, bismuth compounds, lead compounds, cobalt compounds, manganese compounds, titanium compounds and aluminum compounds and an organic solvent (c1). The aqueous multi-component polyurethane coating composition according to any one of items 1 to 8 above, which contains the third component (C).
Item 11. The aqueous multi-component polyurethane according to item 10, wherein the content of the metal catalyst compound (d) is within the range of 0.10 to 5.0 parts based on 100 parts by mass of the total amount of the third component (C). Paint composition.
Item 12. The aqueous multi-component polyurethane coating composition according to any one of items 9 to 11 above, wherein the metal catalyst compound (d) contains a tin compound.
Item 13. Any one of items 9 to 12 above, wherein the content of the metal catalyst compound (d) is within the range of 0.01 to 1.00 parts by mass based on 100 parts by mass of nonvolatile content of the polyisocyanate component (b1). The aqueous multi-component polyurethane coating composition described in 2.
Section 14. Items 1 to 13 above, wherein the organic solvent (b2) contains a compound having a boiling point of 140° C. or more and 180° C. or less and a water solubility at 20° C. of 1.0 g/100 g H ₂ O or more and 20 g/100 g H ₂ O or less. The aqueous multi-component polyurethane coating composition according to any one of the above.
Item 15. Items 1 to 1 above, wherein the content of the organic solvent (b2) is 40 parts by mass or more and 70 parts by mass or less based on 100 parts by mass of the total resin solid content of the first component (A) and the second component (B). 15. The aqueous multi-component polyurethane coating composition according to any one of Item 14.
Section 16. Item 10 above, wherein the organic solvent (c1) contains a compound having a boiling point of 140° C. or more and 180° C. or less and a water solubility at 20° C. of 1.0 g/100 g H ₂ O or more and 20 g/100 g H ₂ O or less. A water-based multi-component polyurethane coating composition.
Section 17. The total content of the organic solvent (b2) contained in the second component (B) and the organic solvent (c1) contained in the third component (C) is the same as that of the resin of the first component (A) and the second component (B). 17. The aqueous multi-component polyurethane coating composition according to item 10 or 16, wherein the amount is 40 parts by mass or more and 70 parts by mass or less, based on 100 parts by mass of the total solid content.
Section 18. The aqueous multi-component polyurethane coating composition according to any one of items 1 to 17 above, which is a transparent coating composition.
Item 19. The aqueous multi-component polyurethane coating composition according to any one of items 1 to 17 above, wherein the first component (A) further contains a pigment.
Section 20. A coating method of coating an object to be coated with the aqueous multi-component polyurethane coating composition according to any one of items 1 to 19 above.
Section 21. 21. The coating method according to item 20, wherein the object to be coated is an automobile, an industrial machine, a construction machine, a railway vehicle, a large vehicle, a ship, or a building structure, or a part thereof.
Section 22. Any one of the above items 1 to 17 may be applied on the coating film already formed on the surface of the painted body or on the base treatment coating film in which the primer surfacer and/or base paint is applied to the damaged part of the painted body. A method for repairing a painted body by applying the water-based multi-component polyurethane paint composition described above.

The aqueous multi-component polyurethane coating composition of the present invention has good storage stability of each component and a suitable pot life. A coating film with excellent hardness can be formed in a short time even under mild drying conditions such as drying at room temperature or forced drying.

Furthermore, the coating film formed using the coating material of the present invention has excellent hardness, a transparent finish, and weather resistance, so it can be widely applied to various uses.

As used herein, the singular forms (a, an, the, etc.) shall include both the singular and the plural unless the context clearly dictates otherwise.
In this specification, "comprise" is a concept that includes "consist essentially of" and "consist of".

The present invention comprises a first component (A) containing a hydroxyl group-containing resin emulsion component (a1), a catalyst compound (a2) and water, and a second component (B) containing a polyisocyanate component (b1) and an organic solvent (b2). An aqueous multi-component polyurethane coating composition containing: wherein the glass transition temperature of the hydroxyl group-containing resin contained in the hydroxyl group-containing resin emulsion component (a1) is 40°C or higher, and the film thickness after drying on a tin plate is 40 μm. The Martens hardness of the coating film was 10 N/mm ² or more and 70 N/mm ² or less, and the film thickness after drying was 40 μm. The coating was baked at 60°C for 20 minutes. This is an aqueous multi-component polyurethane coating composition in which the acetone-extracted coating film residual rate of the coating film is 70% or more. Each component used in the present invention will be explained below.

<First component (A)>
In the present invention, the first component (A) contains a hydroxyl group-containing resin emulsion component (a1) and water.

The amount of the hydroxyl group-containing resin emulsion component (a1) in the first component (A) is such that the hydroxyl group-containing resin emulsion component (a1) is present in a non-volatile amount of 20 to 100 parts by mass of the entire first component (A). 50 parts by weight, especially in the range from 25 to 45 parts by weight are suitable.

In this specification, the non-volatile content or resin solid content means the residue after removing volatile components, and the residue may be solid or liquid at room temperature. For example, it refers to the components remaining after volatile components are removed by treating a sample at 105° C. for 3 hours.

In the present invention, the nonvolatile content concentration of the first component (A) is suitably within the range of 25 to 55% by mass, particularly 30 to 50% by mass, from the viewpoint of pot life and finish quality of the formed coating film.

<Hydroxyl group-containing resin emulsion component (a1)>
The hydroxyl group-containing resin emulsion component (a1) in the present invention is a component containing a resin emulsion in which a hydroxyl group-containing resin is dispersed in a solvent such as water, and conventionally known ones can be used as long as they have coating film-forming ability. Can be used without restrictions. Specific examples include acrylic resin emulsion, acrylic silicone resin emulsion, urethane resin emulsion, fluororesin emulsion, epoxy resin emulsion, polyester resin emulsion, alkyd resin emulsion, melamine resin emulsion, vinyl acetate emulsion, silicone resin emulsion, and vinyl acetate emulsion. Examples include, but are not limited to, Beoba resin emulsion. Further, these may be used alone or in combination of two or more.

The glass transition temperature (hereinafter sometimes abbreviated as Tg) of the hydroxyl group-containing resin contained in the hydroxyl group-containing resin emulsion component (a1) is determined in order to harden the resulting coating film and achieve both polishability and adhesion of the coating film. , 40°C or higher, more preferably 50 to 75°C, particularly preferably 60 to 70°C.

In this specification, the glass transition temperature (Tg) is a value calculated by the following formula. 1/Tg(K)=W1/T1+W2/T2+...Wn/Tn
Tg (℃) = Tg (K) - 273
In the formula, W1, W2,...Wn are the mass fractions of each monomer, and T1, T2...Tn are the glass transition temperatures Tg (K) of the homopolymer of each monomer. Note that the glass transition temperature of the homopolymer of each monomer is as described in POLYMER HANDBOOK Fourth Edition, J. Brandrup, E. h. Immergut, E. A. The glass transition temperature of monomers not described in this document is based on the static value obtained when a homopolymer of the monomer is synthesized with a weight average molecular weight of approximately 50,000. Glass transition temperature.

In this specification, the static glass transition temperature of a resin is measured using a differential scanning calorimeter "DSC-50Q model" (manufactured by Shimadzu Corporation, product name By measuring the change in heat value in the range of -100 to 150 °C at a heating rate of 3 °C/min using , can be measured.

The average particle diameter of the resin particles contained in the hydroxyl group-containing resin emulsion component (a1) should be within the range of 50 to 300 nm, particularly 100 to 200 nm, from the viewpoint of storage stability and finishing properties of the first component (A). Suitable from

In this specification, the average particle diameter of the emulsion component is the value of the volume average particle diameter measured by the Coulter counter method at a measurement temperature of 20°C. Measurement by the Coulter counter method can be performed using, for example, "COULTER N4 type" (manufactured by Beckman Coulter, trade name).

The above-mentioned hydroxyl group-containing resin preferably has a hydroxyl value in the range of 50 to 250 mgKOH/g, particularly 100 to 200 mgKOH/g, and an acid value of 5 to 40 mgKOH, from the viewpoint of coating film properties, polishing properties, and drying properties. /g, particularly preferably within the range of 5 to 30 mgKOH/g.

The solubility parameter (SP value) of the above-mentioned hydroxyl group-containing resin is preferably within the range of 8.7 to 9.3, and 8.8 to 9 Particularly preferred is a range of .2.

The solubility parameter ("SP value" is an abbreviation) represents a measure of intermolecular interaction of liquid molecules. The SP value of a homopolymer of polymerizable monomers is determined by J. Paint Technology, vol. 42, 176 (1970). The SP value of the copolymer of the polymerizable monomer mixture can be calculated and determined using the following formula.
SP value=SP1×fw1+SP2×fw2+……+SPn×fwn
In the above formula, SP1, SP2, ...SPn represent the SP value of the homopolymer of each polymerizable monomer, and fw1, fw2, ...fwn are the mass fractions of each polymerizable unsaturated monomer with respect to the total amount of monomers. represents.

In order to keep the solubility parameter of the hydroxyl group-containing resin within the above range, it is preferable that at least 10% by mass or more of monomers having an SP value of less than 9.3 are included in the copolymerized components, and 15 to 60% by mass. The content is more preferably within the range of 20 to 55% by mass, particularly preferably 20 to 55% by mass.

The hydroxyl group-containing resin emulsion component (a1) of the present invention preferably contains a self-emulsifying emulsion. In this specification, a self-emulsifying emulsion refers to a resin having an ionic functional group such as a carboxyl group synthesized without a solvent or in the presence of a suitable organic solvent, which is added dropwise to water, mixed, and optionally an excess amount of It is an emulsion obtained by dispersing by removing the organic solvent or by optionally removing excess organic solvent after the polymerization reaction and then adding water and dispersing. Since self-emulsifying emulsions do not use emulsifiers, they have excellent water resistance and weather resistance. In addition, since self-emulsifying emulsions are not manufactured from an aqueous medium, it is easy to obtain well-balanced fine particles with relatively low molecular weight and small particle size, and when applied as a water-based paint, it is easy to mix by hand. It is extremely easy to handle and work with paints, and has excellent drying properties and gloss. When a self-emulsifying emulsion is used as the hydroxyl group-containing resin emulsion component (a1), it is possible to obtain an extremely excellent coating film appearance even though it is a water-based paint, and it also has excellent reactivity with the polyisocyanate compound (b1), so it has good weather resistance. A coating film with extremely excellent properties can be obtained.

In the present invention, it is suitable that the hydroxyl group-containing resin emulsion component (a1) contains the hydroxyl group-containing acrylic resin (a1-1) as at least a part of the component, since the hardness of the formed coating film is excellent. There are no restrictions on the water dispersion method of hydroxyl group-containing acrylic resin or the manufacturing method of hydroxyl group-containing acrylic resin emulsion, but for example, in the presence of an organic solvent, a (meth)acryloyl compound is essential and other polymerizable unsaturated compounds are added. A method of dispersing in water a hydroxyl group-containing acrylic resin obtained by polymerizing a polymerizable unsaturated compound component containing a polymerizable unsaturated compound component in one step or in multiple steps, in the presence of water and a dispersion stabilizer, a (meth)acryloyl compound is essential, etc. Examples include a method in which a polymerizable unsaturated compound component containing a polymerizable unsaturated compound is emulsion polymerized in one step or in multiple steps.

Examples of the (meth)acryloyl compound and other polymerizable unsaturated compounds that are copolymerization components of the hydroxyl group-containing acrylic resin emulsion include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, iso -Propyl (meth)acrylate, n-butyl (meth)acrylate, iso-butyl (meth)acrylate, tert-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, octyl (meth)acrylate, 2 - Ethylhexyl (meth)acrylate, nonyl (meth)acrylate, dodecyl (meth)acrylate (lauryl (meth)acrylate), tridecyl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate, cyclohexyl (meth)acrylate , methylcyclohexyl (meth)acrylate, t-butylcyclohexyl (meth)acrylate, cyclododecyl (meth)acrylate, isobornyl (meth)acrylate, adamantyl (meth)acrylate, tricyclodecanyl (meth)acrylate, and other alkyl or cycloalkyl (Meth)acrylate; Carboxyl group-containing polymerizable unsaturated compounds such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, β-carboxyethyl acrylate; 2-acrylamido-2-methylpropanesulfonic acid, allylsulfonic acid , sulfonic acid group-containing polymerizable unsaturated compounds such as styrene sulfonic acid sodium salt, sulfoethyl methacrylate and its sodium salt, ammonium salt; 2-acryloyloxyethyl acid phosphate, 2-methacryloyloxyethyl acid phosphate, 2-acryloyloxypropyl Phosphate group-containing polymerizable unsaturated compounds such as acid phosphate and 2-methacryloyloxypropyl acid phosphate; 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, hydroxy Hydroxyalkyl (meth)acrylates having 2 to 8 carbon atoms such as butyl (meth)acrylate; N-methylol acrylamide; Allyl alcohol; ε-caprolactone-modified acrylic compounds of hydroxyalkyl (meth)acrylates having 2 to 8 carbon atoms; Diethylene glycol (meth)acrylate, triethylene glycol (meth)acrylate, polyethylene glycol (meth)acrylate, dipropylene glycol (meth)acrylate, tripropylene glycol (meth)acrylate, polypropylene glycol (meth)acrylate, polyethylene polypropylene glycol (meth)acrylate Hydroxyl group-containing polymerizable unsaturated compounds such as polyalkylene glycol (meth)acrylate such as acrylate; Aromatic ring-containing polymerizable unsaturated compounds such as benzyl (meth)acrylate, styrene, α-methylstyrene, vinyltoluene; vinyltrimethoxy Polymerizable unsaturated compounds with alkoxysilyl groups such as silane, vinyltriethoxysilane, vinyltris(2-methoxyethoxy)silane, γ-(meth)acryloyloxypropyltrimethoxysilane, γ-(meth)acryloyloxypropyltriethoxysilane, etc. Compounds: Alkoxy such as N-methoxymethyl (meth)acrylamide, N-butoxymethyl (meth)acrylamide, methoxyethyl (meth)acrylate, methoxypropyl (meth)acrylate, ethoxyethyl (meth)acrylate, ethoxypropyl (meth)acrylate, etc. Alkoxy group-containing polymerizable unsaturated compounds such as alkyl (meth)acrylate, polyalkylene glycol monoalkoxy (meth)acrylate such as polyethylene glycol monomethoxy (meth)acrylate; perfluorobutylethyl (meth)acrylate, perfluorooctylethyl ( Perfluoroalkyl (meth)acrylates such as meth)acrylates; Polymerizable unsaturated compounds having fluorinated alkyl groups such as fluoroolefins; Polymerizable unsaturated compounds having photopolymerizable functional groups such as maleimide groups; N-vinylpyrrolidone , vinyl compounds such as ethylene, butadiene, chloroprene, vinyl propionate, vinyl acetate; 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-trishydroxymethylethane di(meth)acrylate, 1,1,1-tris At least two polymerizable unsaturated groups in one molecule, such as hydroxymethylethane tri(meth)acrylate, 1,1,1-trishydroxymethylpropane tri(meth)acrylate, triallyl isocyanurate, diallyl terephthalate, divinylbenzene, etc. Polymerizable unsaturated compounds having; (meth)acrylonitrile, (meth)acrylamide, N,N-dimethylaminoethyl (meth)acrylate, N,N-diethylaminoethyl (meth)acrylate, N,N-dimethylaminopropyl (meth) Nitrogen-containing polymerizable unsaturated compounds such as acrylamide, adducts of glycidyl (meth)acrylate and amine compounds; glycidyl (meth)acrylate, β-methylglycidyl (meth)acrylate, 3,4-epoxycyclohexylmethyl (meth)acrylate , 3,4-epoxycyclohexyl ethyl (meth)acrylate, 3,4-epoxycyclohexylpropyl (meth)acrylate, epoxy group-containing polymerizable unsaturated compounds such as allyl glycidyl ether; 2-isocyanatoethyl (meth)acrylate, m - Isocyanato group-containing polymerizable unsaturated compounds such as isopropenyl-α,α-dimethylbenzyl isocyanate; (meth)acrylates having a polyoxyethylene chain with an alkoxy group at the molecular end; acrolein, diacetone acrylamide, diacetone methacrylamide , acetoacetoxyethyl methacrylate, formylstyrene, carbonyl group-containing polymerizable unsaturated compounds such as vinyl alkyl ketones having 4 to 7 carbon atoms (for example, vinyl methyl ketone, vinyl ethyl ketone, vinyl butyl ketone), etc. . These polymerizable unsaturated compounds can be used alone or in combination of two or more.

In the present invention, the hydroxyl group-containing acrylic resin (a1-1) contained in the hydroxyl group-containing acrylic resin emulsion contains a hydroxyl group-containing polymerizable unsaturated compound, a carboxyl group-containing polymerizable unsaturated compound, and an epoxy group-containing polymerizable unsaturated compound. It is preferable to use a copolymer component.

More preferably, the hydroxyl group-containing acrylic resin emulsion contains a polymerizable unsaturated compound component (1) containing an epoxy group-containing polymerizable unsaturated compound and a polymerizable unsaturated compound component (2) containing a carboxyl group-containing polymerizable unsaturated compound. ) is preferably obtained by dispersing in water a hydroxyl group-containing acrylic resin (a1-1) obtained by polymerizing in multiple stages in the presence of an organic solvent. In this case, the hydroxyl group-containing polymerizable unsaturated compound is contained in either (1) or (2) or both (1) and (2).

In the hydroxyl group-containing acrylic resin emulsion, the method for dispersing the resin in water includes neutralizing some or all of the anionic groups such as carboxyl groups contained in the hydroxyl group-containing acrylic resin with a basic compound and dispersing the resin in water. Alternatively, it is also possible to add and disperse the hydroxyl group-containing acrylic resin in an aqueous medium containing a basic compound.

The weight average molecular weight of the hydroxyl group-containing acrylic resin is preferably in the range of 5,000 to 50,000, more preferably 8,000 to 40,000, and particularly 10,000 to 18,000.

The number average molecular weight or weight average molecular weight in this specification is a value obtained by converting the number average molecular weight or weight average molecular weight measured using gel permeation chromatography (GPC) based on the molecular weight of standard polystyrene. Specifically, "HLC8120GPC" (trade name, manufactured by Tosoh Corporation) was used as a gel permeation chromatograph, and "TSKgel G-4000HXL", "TSKgel G-3000HXL", and "TSKgel G-2500HXL" were used as columns. and "TSKgel G-2000HXL" (trade name, both manufactured by Tosoh Corporation) under the conditions of a mobile phase of tetrahydrofuran, a measurement temperature of 40°C, a flow rate of 1 mL/min, and a detector RI. can.

In the present invention, the hydroxyl group-containing resin emulsion component (a1) can also include a commercially available resin emulsion. Specific commercial product names include "Bihydrol A145", "Bihydrol A2290", "Bihydrol A2427", "Bihydrol A2470", "Bihydrol A2542", "Bihydrol A2546", "Bihydrol A2601", and "Bihydrol A242" manufactured by Covestro. ”, “Burnock WE-303”, “Burnock WE-304”, “Burnock WE-306”, “Burnock WE-308”, “Burnock WE-313” manufactured by DIC Corporation, “Lumiflon FE” manufactured by Asahi Glass Co., Ltd. -4200'', ``Lumiflon FE-4300'', ``Lumiflon FE-4400'', and ``Lumiflon FE-4500''.

The resin solid content of the hydroxyl group-containing resin emulsion component (a1) in the first component (A) is such that when the total mass of the first component (A) is 100 parts by mass, the hydroxyl group-containing resin emulsion component (a1) is 20 parts by mass. The amount is preferably 55 parts by weight, more preferably 20 to 50 parts by weight, and particularly preferably 25 to 45 parts by weight.

<Catalyst compound (a2)>
In the aqueous multi-component polyurethane coating composition of the present invention, the first component (A) contains a catalyst compound (a2) from the viewpoint of curability.

Since the first component (A) contains water, the catalyst compound (a2) is preferably water-soluble or water-dispersible. Examples of such catalyst compounds include carbonates, phosphates, nitrates, sulfates, acetates, fluoro acids and their salts, organic acid salts such as carboxylic acids, oxides, alkali salts, etc. The catalyst compound may be anhydrous or hydrated. Further, the catalyst compound (a2) may be present inside the resin particles of the hydroxyl group-containing resin emulsion (a1).

In the present invention, the catalyst compound (a2) is specifically selected from the group consisting of zinc compounds, tin compounds, zirconium compounds, bismuth compounds, lead compounds, cobalt compounds, manganese compounds, titanium compounds, aluminum compounds, and molybdenum compounds. It is preferable that at least one type of Among these, molybdenum compounds are preferred from the viewpoint of hardness and quick drying properties.

Specifically, the molybdenum compounds include, for example, molybdic acid, potassium molybdate, calcium molybdate, disodium molybdate (VI) dihydrate, ammonium molybdate, lithium molybdate, hexaammonium molybdate tetrahydrate. Molybdate compounds or molybdate salts such as hexaammonium heptamolybdate tetrahydrate, magnesium molybdate, rubidium molybdate, cesium molybdate, cobalt(II) molybdate, manganese(II) molybdate, zinc molybdate, etc. ; Molybdenum oxide; Phosphomolybdic acid compounds or phosphomolybdate salts such as phosphomolybdate n-hydrate, sodium phosphomolybdate n-hydrate, ammonium phosphomolybdate trihydrate; Molybdenum (IV) oxide bisacetylacetonate , bis(acetylacetonato) molybdenum(IV) oxide, molybdenum dioxide tetramethylheptadione, tetraethylammonium molybdate, trimethylstannyl/tetrabutylammonium molybdate, molybdenum alkoxide, molybdenum 2-ethylhexanoate, hexacarbonylmolybdenum, etc. organic molybdenum compounds; and the like.

Among the above-mentioned inorganic compounds, at least one selected from phosphomolybdic acid compounds, phosphomolybdates, molybdic acid compounds, and molybdates is used from the viewpoint of mixing stability with the hydroxyl group-containing resin emulsion (a1). That is suitable.

Catalytic compounds other than the above molybdenum compounds include zinc octylate, manganese octylate, tin octylate, cobalt octylate, titanium octylate, aluminum octylate, and octylate, as they have excellent catalytic activity and are easily available industrially. A carboxylic acid metal salt compound such as zirconium, bismuth octylate, or lead octylate can be suitably used.

The catalyst compounds can be used alone or in combination of two or more.

The content of the catalyst compound (a2) is preferably in the range of 0.0001 to 0.1 part by mass, and more preferably 0.0005 to 0.1 part by mass, based on 100 parts by mass of the resin solid content of the first component (A). More preferably, the amount is within the range of 0.05 parts by mass. The amount is preferably 0.0001 part by mass or more in terms of the curability of the coating film, and it is preferably 0.1 part by mass or less in terms of the water resistance of the coating film.

<Polyether polyol>
In the present invention, the first component (A) may contain a polyether polyol from the viewpoint of finishability and painting workability.

Examples of polyether polyols include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and polyoxyalkylene glyceryl ether, which may be used alone or in combination of two or more. Among these, it is preferable to include polyoxyalkylene glyceryl ether from the viewpoint of improving the finish of the coating film.

The polyoxyalkylene structure in the polyoxyalkylene glyceryl ether can be any one selected from polyoxyethylene, polyoxypropylene, and polyoxybutylene, with polyoxypropylene being preferred.

As the above-mentioned polyether polyol, it is preferable to use one having a number average molecular weight within the range of 100 to 5000, particularly 300 to 1500, and a hydroxyl value within the range of 30 to 400 mgKOH/g, particularly 100 to 350 mgKOH/g.

Commercially available polyether polyols include Sannix PP-400, PP-1000, PP-2000, PP-3000, GP-600, GP-1000, GP-3000, GL-3000, FA-103, and FA-703. (all manufactured by Sanyo Chemical Industries, Ltd.), Exenol EL-1020, EL-2020, EL-3020, EL-510, EL-540, EL-3030, EL-5030, EL-823, EL-828, EL- 830, EL-837, EL-840, EL-850, EL-851B (all manufactured by Asahi Glass Urethane Co., Ltd.), Preminol PML-3005, PML-3012, PML-4002, PML-5001, PML-7001 (all manufactured by Asahi Glass Urethane Co., Ltd.) (manufactured by Asahi Glass Urethane Co., Ltd.).

When the first component (A) contains a polyether polyol, its content should be the total nonvolatile content of the hydroxyl group-containing resin emulsion component (a1) from the viewpoint of the balance between finishing properties, curability, and the hardness of the resulting coating film. Suitably, the amount is in the range of 0.05 to 40 parts by weight, preferably 1 to 25 parts by weight, and more preferably 2 to 15 parts by weight, based on 100 parts by weight.

<Second component (B)>
In the present invention, the second component (B) contains a polyisocyanate component (b1) and an organic solvent (b2).

The resin solid content of the polyisocyanate component (b1) in the second component (B) is 20 to 100 parts by mass, particularly 30 parts by mass, of the polyisocyanate component (b1) in 100 parts by mass of the entire second component (B). A range of 80 parts by mass is suitable.

Furthermore, the amount of the organic solvent (b2) should be in the range of 10 to 300 parts by mass, particularly 30 to 250 parts by mass, based on 100 parts by mass of the polyisocyanate component (b1). is preferred.

In the present invention, the nonvolatile content concentration of the second component (B) is preferably within the range of 20 to 90% by mass, particularly 30 to 80% by mass from the viewpoint of pot life and finish quality of the formed coating film. There is.

<Polyisocyanate component (b1)>
The polyisocyanate compound (b1) is a compound having two or more free isocyanate groups in one molecule, and those conventionally used in the production of polyurethane can be used. Specifically, for example, aliphatic diisocyanates such as tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, and lysine diisocyanate; alicyclic diisocyanates such as 4,4'-methylenebis(cyclohexyl isocyanate) and isophorone diisocyanate; Diisocyanate; Aromatic diisocyanates such as xylylene diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, polyphenylmethane diisocyanate (hereinafter referred to as polymeric MDI); 1,8-diisocyanato-4-isocyanatomethyloctane, (2S)-2,6-diisocyanate; Aliphatic triisocyanates such as 2-isocyanatoethyl isocyanatohexanoate (common name: lysine triisocyanate), 2-isocyanatoethyl 2,6-diisocyanatohexanoate, 1,6,11-triisocyanatoundecane; Alicyclic triisocyanates such as 1,3,5-triisocyanatocyclohexane and 1,3,5-trimethylisocyanatocyclohexane; 1,3,5-triisocyanatobenzene, 2,4,6-triisocyanatotoluene aromatic triisocyanates such as; and similar compounds such as isocyanurates and biurets thereof; these may be used alone or in combination of two or more. In particular, it is preferable that the isocyanate group content is within a specific range. Specifically, from the viewpoint of water resistance, the isocyanate group content is 10% by mass or more, further 12% by mass or more, particularly 18% by mass or more. The content is preferably 60% by mass or less, more preferably 55% by mass or less.

Here, in this specification, the isocyanate group content is the amount of isocyanate groups contained in the polyisocyanate compound (b1) expressed as a mass fraction. The amount of isocyanate groups can be measured in accordance with JIS K 1603-1 (2007).

The polyisocyanate compound (b1) includes a hydrophilized polyisocyanate compound in which a hydrophilic group is introduced into the polyisocyanate compound, and a water-dispersible polyisocyanate in which the polyisocyanate compound can be dispersed in water using a surfactant. Preference is given to using polyisocyanate compounds for water-based paints such as compounds. Examples of the hydrophilic group include anionic groups such as acid groups and nonionic groups containing polyoxyalkylene (polyether chain) units. Examples of acid groups include carboxyl groups, phosphoric acid groups, and sulfonic acid groups.

Furthermore, in addition to the polyisocyanate compound for water-based paints, the curing agent can also contain a hydrophobic polyisocyanate compound in combination. As such hydrophobic polyisocyanate compounds, those commonly used in solvent-based coating compositions can be used.

The polyisocyanate compound (b1) can be used alone or in combination of two or more. When two or more types of polyisocyanate compounds (b1) are used in the second component (B), the isocyanate group content of the polyisocyanate compounds in the second component (B) is More preferably, the blending amount is adjusted to be 5% by mass or more, more preferably 8% by mass or more, 55% by mass or less, and further preferably 50% by mass or less on average.

The content of the polyisocyanate compound (b1) in the aqueous multi-component polyurethane coating composition of the present invention is determined by the equivalent ratio (NCO/ OH) can generally be appropriately adjusted to a value of 0.5 or more and 5.0 or less, but from the viewpoint of curability and weather resistance, it is preferably 1.1 or more and 3.0 or less, and more preferably 1. More preferably, the amount is 2 or more and 2.0 or less. By setting the equivalent ratio (NCO/OH) within the above-mentioned preferred range, there is an advantage that the curing reactivity of the aqueous multi-component polyurethane coating composition can be ensured within a favorable range.

<Organic solvent (b2)>
In the present invention, the organic solvent (b2) contained in the second component (B) together with the polyisocyanate component (b1) is preferably a compound that does not have a hydroxyl group, and specific examples include, for example, ethylene Glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol divinyl ether, diethylene glycol ethyl methyl ether, diethylene glycol isopropyl methyl ether, diethylene glycol butyl methyl ether, triethylene glycol dimethyl ether, triethylene glycol divinyl ether, tetraethylene glycol diethyl ether , propylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol di-n-propyl ether, propylene glycol diisopropyl ether, propylene glycol di-n-butyl ether, propylene glycol diisobutyl ether, propylene glycol diallyl ether, propylene glycol diphenyl ether, dipropylene glycol dimethyl ether , dipropylene glycol diethyl ether, dipropylene glycol di-n-butyl ether, dipropylene glycol diisobutyl ether, dipropylene glycol allyl ether, tripropylene glycol dimethyl ether, tripropylene glycol diethyl ether, tripropylene glycol di-n-butyl ether, tripropylene Glycol diisobutyl ether, tripropylene glycol diallyl ether, butylene glycol dimethyl ether, butylene glycol diethyl ether, butylene glycol di-n-butyl ether, 2-butoxyethyldiethoxyethyl ether, 2-butoxyethyltriethoxyether, 2-butoxyethyltetraethoxy Glycol ether organic solvents such as ethyl ether; ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol mono-n-butyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol mono-n-butyl ether acetate, 3-methoxybutyl Acetate organic solvents such as acetate, propylene glycol monomethyl ether acetate; Ketone organic solvents such as acetone, methyl ethyl ketone, methyl amyl ketone, methyl isobutyl ketone; ethyl acetate, butyl acetate, isobutyl acetate, methyl benzoate, ethyl ethoxypropionate, Examples include ester organic solvents such as ethyl propionate and methyl propionate. These can be used alone or in combination of two or more.

Among them, from the viewpoint of the gloss and finish of the formed coating film, the organic solvent (b2) has a boiling point of 140°C or higher and 180°C or lower, and a water solubility of 1.0g/100g H _{2 O or higher and 20g/100g H 2} O or higher at 20°C. It is preferable to contain a compound having a concentration of ₂ O or less. Examples of such compounds include propylene glycol monomethyl ether acetate, ethyl ethoxypropionate, and the like.

In the present invention, the content of the organic solvent (b2) is determined to be 100 parts by mass of the total resin solid content of the first component (A) and the second component (B) from the viewpoint of gloss and finish of the formed coating film. It is preferably 40 parts by mass or more and 70 parts by mass or less, particularly preferably 45 parts by mass or more and 60 parts by mass or less.

<Metal catalyst compound (d)>
The aqueous multi-component polyurethane coating composition of the present invention contains at least one metal selected from the group consisting of zinc compounds, tin compounds, zirconium compounds, bismuth compounds, lead compounds, cobalt compounds, manganese compounds, titanium compounds, and aluminum compounds. It is preferable to contain a catalyst compound (d). This metal catalyst compound acts as a urethanization catalyst.

The metal catalyst compound (d) can be included in the second component (B) and/or the optional third component (C) described below. The metal catalyst compound (d) is preferably added to the second component (B) when a two-component coating composition is desired with emphasis on painting workability, and the storage stability of the second component (B) is preferred. In this case, it is preferable to add it as the third component (C). By adding the metal catalyst compound (d) to the second component (B) and/or the third component (C), the amount of catalyst compound (a2) added to the first component can be minimized, so It becomes possible to achieve both dryness and/or coating film hardness and water resistance. Further, since the second component (B) and the third component (C) are organic solvents, catalyst compounds that do not dissolve or disperse in water, catalyst compounds that are deactivated in water, etc. can also be used.

Specific examples of the metal catalyst compound (d) include zinc compounds such as zinc octylate, zinc naphthenate, zinc fatty acid; tin octylate, dibutyltin di(2-ethylhexanoate), dioctyltin Tin compounds such as di(2-ethylhexanoate), dioctyltin diacetate, dibutyltin dilaurate, dioctyltin dilaurate, dioctyltin dineodecanate, dibutyltin oxide, dioctyltin oxide, dibutyltin fatty acid salt; zirconium tetra(monomethyl ethoxide) ), zirconium compounds such as zirconium tetra (monoethyl ethoxide), zirconium tetra (monobutyl ethoxide), zirconium normal propylate, zirconium normal butyrate, zirconium tetrakis (acetylacetonate); bismuth octoate, 2-ethylhexane Bismuth compounds such as bismuth acid, bismuth oleate, bismuth neodecanoate, bismuth versatate, bismuth naphthenate, bismuth nitrate; Lead compounds such as lead oleate, lead 2-ethylhexanoate, lead fatty acid; cobalt octylate, naphthenic acid Cobalt compounds such as cobalt; manganese compounds such as manganese (II) acetate, manganese (II) acetylacetate, manganese (II)-2-ethylhexanate; titanium tetrachloride, dibutyl titanium dichloride, titanium tetra (monoethyl ethoxide); ), titanium compounds such as titanium tetra (monoethyl ethoxide), titanium tetra (monobutyl ethoxide), titanium tetrakis (acetylacetonate), tetra-n-butyl titanate; aluminum trimethoxide, aluminum tris (acetylacetonate), Examples include aluminum compounds such as aluminum tri-n-butoxide, aluminum tris (ethyl acetoacetate), aluminum diisopropoxy (ethyl acetoacetate), and aluminum acetylacetonate, and these may be used alone or in combination of two or more. I can do it. From the viewpoint of curability, it is preferable to use tin compounds, such as dibutyltin di(2-ethylhexanoate), dioctyltin di(2-ethylhexanoate), dioctyltin diacetate, dibutyltin dilaurate, dioctyltin dilaurate. It is particularly preferable to use at least one selected from , and dioctyltin dineodecanate.

The content of the metal catalyst compound (d) is preferably within the range of 0.01 to 1.00 parts by mass, based on 100 parts by mass of nonvolatile content of the polyisocyanate component (b1), and preferably 0.02 to 0.00 parts by mass. It is more preferably within the range of 80 parts by mass, and particularly preferably within the range of 0.03 to 0.60 parts by mass. When the amount is 0.01 parts by mass or more, the curability of the coating film is improved, and when it is 1.00 parts by mass or less, the finishability of the coating film is good.

<Third component (C)>
The aqueous multi-component polyurethane coating composition of the present invention may optionally contain a third component (C) containing an organic solvent (c1) in addition to the first component (A) and the second component (B). can. The third component (C) is a different component from the first component (A) and the second component (B). When the aqueous multi-component polyurethane coating composition contains the third component (C), the third component preferably contains the metal catalyst compound (d).

As the organic solvent (c1), the organic solvents described in the organic solvent (b2) above can be suitably used. The organic solvent (c1) and the organic solvent (b2) may be the same or different.

The total content of the organic solvent (b2) and the organic solvent (c1) is 40 parts by mass or more and 70 parts by mass or less, based on 100 parts by mass of the total resin solid content of the first component (A) and the second component (B). The content is preferably 45 parts by mass or more and 60 parts by mass or less.

When the third component (C) contains a metal catalyst compound (d), the content is in the range of 0.10 to 5.0 parts by mass based on 100 parts by mass of the total amount of the third component (C). The amount is preferably in the range of 0.10 to 3.0 parts by mass.

<Aqueous multi-component polyurethane coating composition>
The aqueous multi-component polyurethane coating composition of the present invention includes a resin emulsion or water-soluble resin other than the hydroxyl group-containing resin emulsion component (a1), a pigment, a neutralizing agent, a rheology control agent, a surface conditioner, an antifoaming agent, and an ultraviolet absorber. A light stabilizer, a dehydrating agent, an organic solvent, etc. can be optionally blended into the first component (A), second component (B), and third component (C).

As the pigment, conventionally known pigments can be used, such as colored pigments such as titanium white, carbon black, and red iron; metallic pigments such as fine aluminum powder; calcium carbonate, clay, talc, mica, baryta, silica, alumina white, etc. Extender pigments such as aluminum tripolyphosphate, aluminum phosphomolybdate, and zinc phosphate anticorrosive pigments; etc. These can be used alone or in combination of two or more depending on the desired color and/or coating performance. can be used.

The colored pigment may be added directly to the paint, or it may be mixed with a dispersion resin, dispersed, made into a paste, and then incorporated into the paint. Known dispersion resins and dispersion methods can be used.

Although the pigment can be blended into any of the first component (A), second component (B), and third component (C), it is preferably blended into the first component (A). The amount to be blended is preferably in the range of 1 to 250 parts by weight in terms of solid content, based on 100 parts by weight of the nonvolatile content of the hydroxyl group-containing resin emulsion component (a1).

Among these, rheology control agents include polyamide rheology control agents such as fatty acid amide, polyamide, acrylamide, long chain polyaminoamide, aminoamide and salts thereof (e.g. phosphates);
Urethane rheology control agents such as polyether polyol-based urethane prepolymers and urethane-modified polyether-type viscosity modifiers; polycarboxylic acid-based agents such as high molecular weight polycarboxylic acids, high molecular weight unsaturated acid polycarboxylic acids, and partially amidated products thereof. Rheology control agents; cellulose rheology control agents such as hydroxyethyl cellulose and hydroxypropyl cellulose; inorganic layered compound rheology control agents such as montmorillonite, bentonite, and clay; aminoplast rheology control agents such as hydrophobically modified ethoxylate aminoplast, etc. It is possible to use only one type, or a mixture of two or more types.

Commercially available rheology control agents include "Disparon AQ-600" (trade name, manufactured by Kusumoto Kasei Co., Ltd.), "Anti-Terra-U", "Disperbyk-101", "Disperbyk-130", and "Anti-Terra". -203/204", "Disperbyk-107", "BYK-P104", "BYK-P105", "Optiflo H600VF" (manufactured by BYK Chemie), "ACRYSOL ASE60" (manufactured by Dow Chemical), "Visca "Rex HV-30" (manufactured by Clariant Japan Co., Ltd.), "SN Thickener 617", "SN Thickener 618", "SN Thickener 630", "SN Thickener 634", "SN Thickener 636" (product names listed above, manufactured by San Nopco Co., Ltd.) manufactured by ADEKA Co., Ltd.); “ADEKA NOL UH-814N”, “UH-752”, “UH-750”, “UH-462” (all product names manufactured by ADEKA Co., Ltd.), “SN Thickener 621N”, “SN Thickener 623N” ( The above product names are manufactured by San Nopco Co., Ltd.), "Rheolate 244", "Reolate 278" (the above product names are manufactured by Elementis Japan Co., Ltd.); "HEC Daicel SP600N" (product name is manufactured by Daicel Chemical Industries, Ltd.) ; "BENTONE HD" (trade name, manufactured by Elementis Japan Co., Ltd.), etc., and can be used alone or in combination of two or more kinds.

In the present invention, it is suitable to use a polycarboxylic acid rheology control agent and/or a nonionic rheology control agent as the rheology control agent from the viewpoint of the sagging resistance of the formed coating film.

Examples of nonionic rheology control agents include urethane rheology control agents, cellulose rheology control agents, layered compound rheology control agents, and aminoplast rheology control agents among the above-mentioned examples.

The above rheology control agent can be blended into any of the first component (A), second component (B), and third component (C), but the blending amount is as follows: hydroxyl group-containing resin emulsion component (a1) non-volatile content: 100% The mass of the active ingredient of the rheology control agent is preferably 0.01 to 1.0 parts by mass, more preferably 0.1 to 0.5 parts by mass, based on parts by mass.

The aqueous multi-component polyurethane coating composition of the present invention comprises a first component (A) containing the hydroxyl group-containing resin emulsion component (a1) and water, and a first component containing the polyisocyanate component (b1) and an organic solvent (b2). The two components (B) and optionally the third component (C) can be mixed immediately before use and the resulting mixture can be diluted appropriately and applied. The ratio of the first component (A) and the second component (B) to be used is 20 to 100 parts by mass, particularly 30 to 70 parts by mass of the second component (B) based on 100 parts by mass of the first component (A). A suitable ratio is such that When using the third component (C), the proportion of the third component (C) is preferably 0.1 to 20 parts by mass, particularly 1 to 10 parts by mass based on 100 parts by mass of the first component (A). ing.

The aqueous multi-component urethane paint composition of the present invention can be used as either a transparent paint or an opaque paint; however, since it can form a transparent finished appearance and a paint film with excellent hardness, it is preferable to use a clear paint film. The effect can be maximized when the composition is a transparent coating composition.

The aqueous multi-component urethane coating composition of the present invention can form a coating film with excellent finished appearance, hardness, and weather resistance, so it can maximize its effects when used as a top coating composition.

In addition, when the coating composition of the present invention is used as an opaque coating, there are no particular restrictions on the pigment used, and as mentioned above, pigments known in the coating field such as coloring pigments, extender pigments, and antirust pigments are exemplified. The type and amount can be adjusted depending on the purpose and use.

<Martens hardness>
The aqueous multi-component polyurethane coating composition of the present invention is coated on a tin plate to a dry film thickness of 40 μm and baked at 60°C for 20 minutes, resulting in a Martens hardness of 10 N/mm ² or more and 70 N/mm. mm ² or less. From the viewpoint of shortening the polishing time, it is preferable that the current is 10 N/mm ² ^or more, preferably 20 N/mm 2 or more, and more preferably 30 N/mm ² or more. In addition, from the viewpoint of finishability and polishability, it is preferable that the strength is 70N/mm ² or less, preferably 60N/mm ² or less, more preferably 50N/mm ² or less.

The Martens hardness in this specification can be measured using Fischerscope (registered trademark) HM2000S (trade name, manufactured by Fischer Instruments Inc.). Measurement is performed by pressing the indenter at a speed of 4.0 μm/20 seconds in an atmosphere of 23° C. and 50% relative humidity. A Vickers square pyramid (material: diamond) is used as the indenter, and the position of the sample is adjusted so that the indenter action point is near the center of one peak of the prism part.

The steps for measuring Martens hardness in this specification are the following 1) to 4).
1) Push in the indenter at a speed of 4.0 μm/20 seconds.
2) Unload at the same speed.
3) Repeat steps 1) and 2) while changing the measurement position to obtain data from three points per sample.
4) Calculate the Martens hardness from the relationship between the test force and the indentation depth, and take the average value of the three points.

<Acetone extraction coating film residual rate>
The aqueous multi-component polyurethane coating composition of the present invention is coated to a dry film thickness of 40 μm and baked at 60° C. for 20 minutes, and has an acetone-extracted coating film survival rate of 70% or more. From the viewpoint of hardenability and shortening of polishable time, it is preferable that the content is 70% or more, preferably 72% or more, and more preferably 75% or more. Further, from the viewpoint of finishability and polishability, it is preferable that it is 95% or less, preferably 93% or less, and more preferably 90% or less.

In this specification, the acetone extraction coating film residual rate shall be measured as follows.

A coating film is prepared by coating a polypropylene plate so that the film thickness after drying is 40 μm and baking it at 60°C for 20 minutes, peeling the coating film from the polypropylene plate, placing it in a wire mesh, and measuring the mass. This coated wire mesh was left in an acetone solvent for one day at a temperature of 20° C. and a relative humidity of 50%, and then vibrated with an ultrasonic device for about one hour to dissolve it.

Thereafter, the wire gauze containing the remaining paint film was taken out and dried at 105° C. for 1 hour, and then its mass was measured, and the acetone extraction paint film residual rate was calculated using the following formula.
Acetone extraction coating film residual rate (%) = (mass of wire mesh with residual coating film - mass of wire mesh) / (mass of wire mesh with coating film before acetone extraction - mass of wire mesh) x 100

<Object to be coated>
The substrate to which the aqueous multi-component polyurethane coating composition of the present invention is applied is not particularly limited, and includes, for example, metals such as aluminum, iron, stainless steel, zinc, copper, and tinplate; glass, concrete, slate plates, etc. Inorganic materials; organic materials such as plastics and vinyl chloride; wood, etc. These surfaces may be coated with water-based or solvent-based paints, or may be damaged painted bodies. In particular, the aqueous multi-component polyurethane coating composition of the present invention is suitable for applying a primer surfacer and/or base paint onto the coating film (old coating film) already formed on the surface to be coated of the painted body or on damaged parts of the painted body. It can be suitably used on a painted base treatment coating, and in that case, it is particularly preferable to use it for repairing the coated surface of an automobile body.

Specific examples of objects to be coated include automobiles, industrial machinery, construction machinery, railway vehicles, large vehicles, ship hulls, buildings or structures, or parts thereof; outdoor structures such as buildings and steel structures; etc. Examples include, but are not limited to.

<Painting and drying>
Methods for applying the aqueous multi-component urethane coating composition of the present invention include, for example, air spray, airless spray, rotary atomization, brush, roller, hand gun, all-purpose gun, dipping, roll coater, curtain flow coater, and roller curtain. Coaters, die coaters, etc. can be used, and can be appropriately selected depending on the purpose of the object to be coated, and the coating may be applied multiple times.

The aqueous multi-component urethane coating composition of the present invention can form a coating film with excellent finish even when dried at room temperature at a temperature of 5°C to 40°C, but it may also be subjected to forced drying or baking drying.

In the case of forced drying, heating can be performed at 40 to 120°C for 10 to 120 minutes, and a step (setting time) of leaving the product at room temperature to volatilize the solvent may optionally be provided before forced drying.

The dry film thickness can be appropriately selected depending on the application, but is generally preferably within the range of 5 to 500 μm, more preferably 10 to 100 μm, and even more particularly 15 to 80 μm.

Since the coating composition of the present invention has excellent drying properties and provides a coating film with excellent hardness, when it is used for repair painting of automobiles, etc., the surface is polished at an early stage after the coating film is formed. be able to.

Examples of the polishing method include a method in which the coating film is wet-polished using waterproof abrasive paper, and then the polished surface is sequentially polished with a rough polishing compound and a final polishing compound.

Hereinafter, the present invention will be further explained with reference to Examples. Here, "parts" and "%" mean "parts by mass" and "% by mass", respectively.

<Manufacture of acrylic resin emulsion>
Manufacturing example 1
Fifty parts of propylene glycol monopropyl ether was placed in a four-neck glass flask equipped with a thermometer, a stirrer, a reflux condenser, and a nitrogen inlet, and the temperature was raised to 120° C. under a nitrogen stream while stirring. When the temperature reached 120°C, a mixed solution of 1.5 parts of t-butylperoxy-2-ethylhexanoate was mixed in advance with the monomer formulation and polymerization initiator listed in the first stage column of Table 1 for 4 hours. After dropping, the temperature was maintained at 120° C. for 1 hour. Subsequently, while maintaining the temperature at 120°C, the monomer formulation described in the second stage column of Table 1 and 0.3 part of t-butylperoxy-2-ethylhexanoate were mixed in advance in the above flask. The mixed solution was added dropwise over 1 hour, and after the addition was completed, the mixture was maintained at 120°C for 1.5 hours to obtain an acrylic polyol solution. Subsequently, propylene glycol monopropyl ether was distilled off from the obtained acrylic polyol solution under reduced pressure until the nonvolatile content became 85%. This was cooled to 95°C, the pH was adjusted to 8.0 with dimethylethanolamine, and the mixture was stirred for 30 minutes. Further, deionized water was added dropwise over 2 hours to obtain a water dispersion (emulsion) of acrylic resin while stirring so that the nonvolatile content was 50%.

Production example 2 and production example 3
Acrylic resin emulsions (a1-2) and (a1-3) were obtained in the same manner as in Production Example 1, except that the monomer composition and blending amount of each copolymer component were as shown in Table 1 below. Ta.

Production example 4
Fifty parts of propylene glycol monopropyl ether was placed in a four-neck glass flask equipped with a thermometer, a stirrer, a reflux condenser, and a nitrogen inlet, and the temperature was raised to 120° C. under a nitrogen stream while stirring. When the temperature reached 120°C, a mixed solution of the monomer formulation listed in the first stage column of Table 1 below and 1.5 parts of polymerization initiator t-butylperoxy-2-ethylhexanoate was heated for 4 hours. After dropping, the temperature was maintained at 120° C. for 1 hour. Subsequently, while maintaining the temperature at 120° C., the monomer formulation described in the second stage column of Table 1 and 0.3 part of t-butylperoxy-2-ethylhexanoate were mixed in advance in the above flask. The mixed solution was added dropwise over a period of 1 hour, and after the addition was completed, the mixture was maintained at 120° C. for 1.5 hours to obtain an acrylic polyol solution. Subsequently, propylene glycol monopropyl ether was distilled off from the obtained acrylic polyol solution under reduced pressure until the nonvolatile content became 85%. This was cooled to 95° C., 5 parts of “Newcol 707SF” (Note 1) was added, and the mixture was stirred for 30 minutes.
Furthermore, deionized water was added dropwise over 2 hours to obtain an acrylic resin emulsion (a1-4) while stirring so that the nonvolatile content was 50%.

The weight average molecular weight, acid value, hydroxyl value average particle diameter, and glass transition temperature of the acrylic resin emulsions obtained in Production Examples 1 to 4 are shown in Table 1 below.

(Note 1) "Nukol 707SF": Trade name, manufactured by Nippon Nyukazai Co., Ltd., polyoxyethylene polycyclic phenyl ether sulfate salt.

<Manufacture of aqueous multi-component polyurethane coating composition>
Example 1
In a container, 70 parts of the 50% non-volatile content acrylic resin emulsion (a1-1) obtained in Production Example 1 (resin solid content 35 parts), 0.5 part of "BYK-348" (Note 4), and "BYK- 015” (Note 5) 0.1 part, “TINUVIN384-2” (Note 6) 1 part, “TINUVIN292” (Note 7) 0.5 part, sodium phosphomolybdate n-hydrate 0.001 part, deionized 27.5 parts of water was blended, and dimethylethanolamine (Note 9) was added dropwise under stirring at room temperature to prepare a first liquid (A).

In a separate container, 22.5 parts of "Bihydur XP2655" (Note 10) and 27.5 parts of ethyl ethoxypropionate were blended and mixed until homogeneous to prepare a second liquid (B).

100 parts of the first liquid (A) and 50 parts of the second liquid (B) are mixed, and deionized water is added so that the nonvolatile content is 40%, and the mixture is stirred to obtain an aqueous solution. A multi-component polyurethane coating composition (X-1) was obtained.

Examples 2 to 20 and Comparative Examples 1 to 8
In Example 1, water-based multi-component polyurethane coating compositions (X-2) to (X- 20), (X-22) to (X-29) were obtained.

Example 21
35 parts of propylene glycol monopropyl ether was charged into a reaction vessel equipped with a thermometer, a thermostat, a stirring device, a reflux condenser, a nitrogen inlet tube, and a dropping device, and after raising the temperature to 85°C, 18 parts of methyl methacrylate and 29 parts of n-butyl acrylate were added. parts, 35 parts of isobornyl acrylate, 10 parts of 2-hydroxyethyl acrylate, 6.5 parts of acrylic acid, 1.5 parts of 2-methacryloyloxyethyl acid phosphate, 15 parts of propylene glycol monopropyl ether, and 2,2'-azobis. A mixture of 2.3 parts of (2,4-dimethylvaleronitrile) was added dropwise over 4 hours, and the mixture was aged for 1 hour after the addition was completed. Thereafter, a mixture of 10 parts of propylene glycol monopropyl ether and 1 part of 2,2'-azobis(2,4-dimethylvaleronitrile) was added dropwise over 1 hour, and the mixture was aged for 1 hour after the addition was completed. Further, 7.4 parts of diethanolamine and propylene glycol monopropyl ether were added to obtain a colorless and transparent water-soluble acrylic resin solution (a3) containing carboxyl groups and phosphoric acid groups with a solid content of 50%. The obtained acrylic resin (a3) could be used as a pigment dispersion resin, and had an acid value of 54.6 mgKOH/g and a hydroxyl value of 48 mgKOH/g. 6 parts of the obtained acrylic resin (a3) and 20 parts of "TITANIX JR-903" (Note 3) were mixed, and further 20 parts of deionized water was added and mixed. Next, glass beads with a diameter of about 1.5 mm were added and dispersed in a sand mill until the particle size became 10 μm or less as measured by a particle gauge, and the glass beads were removed to obtain a dispersed paste.

In a container, 46 parts of the above dispersion paste (6 parts of 50% acrylic resin (A3), 20 parts of "TITANIX JR-903", 20 parts of deionized water) and the 50% non-volatile content acrylic resin emulsion obtained in Production Example 1 were added. (a1-1) 64 parts (solid content 32 parts), "BYK-348" (Note 4) 0.5 part, "BYK-015" (Note 5) 0.1 part, "TINUVIN384-2" (Note 6) ), 0.5 part of "TINUVIN292" (Note 7), 0.001 part of sodium phosphomolybdate n-hydrate, and 7.5 parts of deionized water, and dimethylethanolamine (Note 7) was added under stirring at room temperature. 9) was added dropwise to prepare a first solution (A).

120 parts of the first liquid (A) and 50 parts of the second liquid (B) are mixed, and deionized water is added so that the nonvolatile content is 45%, and the mixture is stirred to form an aqueous solution. A multi-component polyurethane coating composition (X-21) was obtained.

Examples 22 to 26 and Comparative Example 11
A first liquid (A) and a second liquid (B) were prepared in the same manner as in Example 1, except that the amounts of each coating composition were as shown in Table 5.

In addition, the materials listed in "Third Liquid (C)" in Table 7 were mixed in a separate container and mixed until homogeneous to prepare a Third Liquid (C).

Mix the first liquid (A), second liquid (B), and third liquid (C) in the proportions shown in Table 7, and add deionized water so that the nonvolatile content is 40%. The mixture was stirred to obtain aqueous multi-component polyurethane coating compositions (X-30) to (X-35).

Note 2) "Sannix GP-600": Product name, manufactured by Sanyo Chemical Industries, Ltd., polyoxypropylene glyceryl ether, number average molecular weight 600, hydroxyl value 280 mgKOH/g, non-volatile content 100%
Note 3) "TITANIX JR-903": Product name, manufactured by Teika Co., Ltd., titanium oxide Note 4) "BYK-348": Product name, manufactured by BYK Chemie Japan Co., Ltd., polyether modified siloxane, weight average molecular weight 1,500 , 100% non-volatile content
Note 5) "BYK-015": Product name, manufactured by BYK-Chemie Japan Co., Ltd., polyether-modified siloxane, weight average molecular weight 2,200, non-volatile content 100%
Note 6) "TINUVIN 384-2": Product name, manufactured by BASF, benzotriazole ultraviolet absorber, non-volatile content 95%, 1-methoxy-2-propyl acetate 5%,
Note 7) “TINUVIN 292”: Product name, manufactured by BASF, hindered amine light stabilizer, non-volatile content 100%
Note 8) “K-KAT Dropwise until the temperature reaches .6 Note 10) "Byhydur XP2655": Product name, manufactured by Sumika Covestro Urethane Co., Ltd., hexamethylene diisocyanate-based polyisocyanate having sulfonic acid groups, NCO content 21%, non-volatile content 100%.
Note 11) "Desmodur N3900": Trade name, manufactured by Sumika Covestro Urethane Co., Ltd., hydrophobic polyisocyanate, cyclized polymer of hexamethylene diisocyanate, NCO content 23.5%, non-volatile content 100%
Note 12) “Neostane U-810”: Product name, manufactured by Nitto Kasei Co., Ltd., dioctyltin compound

<Evaluation test>
Tables 2 to 7 above list the results of the evaluation tests described below. In the present invention, it is important that all the performances are excellent, and if any one of them has a failure rating of "C", it is a failure.

<Preparation of object to be coated and coating plate for evaluation>
A painted board coated with a clear paint for automobile bodies was polished and degreased with #800 waterproof paper. This was placed horizontally and a commercially available water-based colored base paint composition "Rethane WB Eco Base" (trade name, water-based metallic base paint for automobile refinishing manufactured by Kansai Paint Co., Ltd.) was uniformly applied under the conditions of 25°C and 40% relative humidity. A colored base coating film having a total thickness of 15 μm was obtained by repeating the coating in three stages so that the color was as follows. After each stage of painting, air blowing was performed until the solvent volatilized and the gloss became low (specifically, the gloss level was about 25). The plate on which the metallic colored base coating film was formed was used as a coated object (V).

The paint compositions obtained in the Examples and Comparative Examples were air-sprayed onto the object to be coated (V) so that the dry film thickness was 40 μm, and then the coated plate was held horizontally for 20 minutes at 25°C and a relative humidity of 40°C. %, dried at 60° C. for 20 minutes using an electric hot air dryer, and cooled to room temperature to prepare test coated plates for evaluation coated with each coating composition as a top coat.

A tin plate was air-sprayed with each coating composition obtained in Examples and Comparative Examples to a dry film thickness of 40 μm, and then the coated plate was applied horizontally for 20 minutes at 25°C and 40% relative humidity. After being kept at 100° C., it was dried at 60° C. for 20 minutes using an electric hot air dryer and cooled to room temperature to prepare a test coated plate for Martens hardness evaluation.

Using a Martens hardness Fischer scope HM2000S (manufactured by FISCHER), an indenter was pressed into the surface of each test coated plate for Martens hardness evaluation, and the Martens hardness value obtained from the pressing depth and pressing force at that time was measured. The specific measurement procedure is as described in the specification.

Acetone extraction coating film survival rate A polypropylene plate was coated with each coating composition obtained in the Examples and Comparative Examples so that the film thickness after drying was 40 μm, and baked at 60°C for 20 minutes to prepare a polypropylene plate. Peel the coating from the board, place it in a wire mesh, and measure the mass. This coated wire mesh was left in an acetone solvent for one day, and then vibrated with an ultrasonic device for about one hour to dissolve it.
Thereafter, the wire gauze containing the remaining paint film was taken out and dried at 105° C. for 1 hour, and then its mass was measured, and the acetone extraction paint film residual rate was calculated using the following formula.
Acetone extraction coating film residual rate (%) = (mass of wire mesh with residual coating film - mass of wire mesh) / (mass of wire mesh with coating film before acetone extraction - mass of wire mesh) x 100

<Storage stability>
The storage stability of the first liquid (first component), second liquid (second component), third liquid (third component), etc. was evaluated according to the following criteria.

First liquid storage stability (appearance, color)
After storing the first liquids prepared in Examples and Comparative Examples at 40° C. for one month, changes in appearance and color were evaluated.
S: Very good with no separation, gelation, discoloration, etc.
A: Good with almost no separation, gelation, discoloration, etc.
B: Slight separation, gelation, discoloration, etc. are observed.
C: Significant separation, gelation, discoloration, etc. are observed.

2nd liquid storage stability (appearance, color)
The second liquids prepared in Examples and Comparative Examples were stored at 40° C. for one month, and then changes in appearance and color were evaluated.
S: Very good with no separation, gelation, discoloration, etc.
A: Good with almost no separation, gelation, discoloration, etc.
B: Slight separation, gelation, discoloration, etc. are observed.
C: Significant separation, gelation, discoloration, etc. are observed.

Third liquid storage stability (appearance, color)
After storing the third liquids prepared in Examples and Comparative Examples at 40° C. for one month, changes in appearance and color were evaluated.
S: Very good with no separation, gelation, discoloration, etc.
A: Good with almost no separation, gelation, discoloration, etc.
B: Slight separation, gelation, discoloration, etc. are observed.
C: Significant separation, gelation, discoloration, etc. are observed.

<Possible polishing time>
Possible polishing time The paint compositions obtained in the Examples and Comparative Examples were air-sprayed onto the object (V) so that the dry film thickness was 40 μm, and then under the conditions of 25° C. and 40% relative humidity. Leave to stand for 20 minutes, then use an electric hot air dryer to dry at 60°C for varying drying times of 20, 30, and 40 minutes to create multiple coated plates for drying evaluation with different drying times at 60°C for the same paint sample. did. Next, the following polishing and repair method (*) was performed on each coated plate for drying evaluation, and a coated plate for drying evaluation with a good coating state and no paper scratches or loss of gloss was selected from among them.
S: Possible to polish and repair with test coated plate with drying time of 20 minutes.
A: Polishing and repair is possible with a test coated plate that takes 30 minutes to dry.
B: Polishing and repair is possible with a test coated plate with a drying time of 40 minutes.
C: It is impossible to polish and repair the test coated plate with a drying time of 40 minutes.
(*Polishing repair method)
After each coated plate for trial drying evaluation was wet-sanded using #2000 water-resistant abrasive paper, it was polished for 60 seconds using a rough-polishing buff with a rough-polishing compound to remove paper scratches caused by the water-resistant abrasive paper. Furthermore, buffing scratches were removed by polishing with a finishing buff using a finishing compound for 60 seconds.

<Coating film performance>
Using the above evaluation test coated plate, coating film performance was evaluated based on the following criteria.

Finishing quality S: Very good smoothness and gloss,
A: Good smoothness and gloss,
B: Slight shine is observed.
C: Significant glossiness is observed.

Water Resistance The test coated plate for evaluation was immersed in a constant temperature water bath at 40° C. for 10 days, taken out, and left to stand for 1 hour, after which the state of the coating film was visually evaluated.
S: No abnormality.
A: At least one abnormality of shine, cracks, and blisters (or sometimes called blisters) is slightly observed.
B: At least one abnormality such as shine, cracks, and blisters is partially observed.
C: At least one abnormality such as shine, cracks, and blisters is clearly observed on the entire surface of the coating film.

Weather resistance Regarding the above test coated plate for evaluation, according to JIS B 7754, using a "Super Xenon Weather Meter" (manufactured by Suga Test Instruments Co., Ltd., weather resistance tester), the test piece wetting cycle: 18 minutes / 2 hours, black Continuous operation was performed at panel temperature: 61 to 65°C. The state of the coating film after 2000 hours was visually evaluated.
S: No abnormality.
A: At least one abnormality of shine, cracks, and blisters (or sometimes called blisters) is slightly observed.
B: At least one abnormality such as shine, cracks, and blisters is partially observed.
C: At least one abnormality such as glossiness, cracking, and blistering is clearly observed on the entire surface of the coating film.

Claims

A water-based resin emulsion containing a hydroxyl group-containing resin emulsion component (a1), a first component (A) containing a catalyst compound (a2) and water, and a second component (B) containing a polyisocyanate component (b1) and an organic solvent (b2). A multi-component polyurethane coating composition, comprising:
The glass transition temperature of the hydroxyl group-containing resin contained in the hydroxyl group-containing resin emulsion component (a1) is 40° C. or higher,
The Martens hardness of the coating film that is coated on a tin plate so that the film thickness after drying is 40 μm and baked at 60°C for 20 minutes is 10 N/mm 2 or more and 70 N/mm 2 or less, and the film thickness after drying is 40 μm. An aqueous multi-component polyurethane coating composition, which has an acetone-extracted coating film residual rate of 70% or more after being painted and baked at 60° C. for 20 minutes.
The aqueous multi-component polyurethane coating composition according to claim 1, wherein the acetone-extracted coating film residual rate of the coating film that is coated to have a film thickness of 40 μm after drying and baked at 60° C. for 20 minutes is 95% or less.
The aqueous multi-component polyurethane paint according to claim 1, wherein the hydroxyl group-containing resin contained in the hydroxyl group-containing resin emulsion component (a1) has a hydroxyl value of 50 to 250 mgKOH/g and an acid value of 5 to 40 mgKOH/g. Composition.
The aqueous multi-component polyurethane coating composition according to claim 1, wherein the hydroxyl group-containing resin emulsion component (a1) contains a self-emulsifying emulsion.
The hydroxyl group-containing resin contained in the hydroxyl group-containing resin emulsion component (a1) contains, as some of its components, a hydroxyl group-containing polymerizable unsaturated compound, a carboxyl group-containing polymerizable unsaturated compound, and an epoxy group-containing polymerizable unsaturated compound. The aqueous multi-component polyurethane coating composition according to claim 1, comprising a hydroxyl group-containing acrylic resin (a1-1) having as a copolymerization component.
The aqueous multi-component polyurethane coating composition according to claim 5, wherein the hydroxyl group-containing acrylic resin (a1-1) has a molecular weight of 10,000 to 18,000.
The aqueous multi-component polyurethane coating composition according to claim 1, wherein the catalyst compound (a2) contains a molybdenum compound.
The aqueous multi-liquid according to claim 1, wherein the content of the catalyst compound (a2) is within the range of 0.0001 to 0.1 part by mass based on 100 parts by mass of the resin solid content of the first component (A). Type polyurethane paint composition.
The second component (B) is at least one metal catalyst compound (d) selected from the group consisting of zinc compounds, tin compounds, zirconium compounds, bismuth compounds, lead compounds, cobalt compounds, manganese compounds, titanium compounds, and aluminum compounds. The aqueous multi-component polyurethane coating composition according to claim 1, comprising:
Contains at least one metal catalyst compound (d) selected from the group consisting of zinc compounds, tin compounds, zirconium compounds, bismuth compounds, lead compounds, cobalt compounds, manganese compounds, titanium compounds and aluminum compounds and an organic solvent (c1). The aqueous multi-component polyurethane coating composition according to claim 1, which contains a third component (C).
The aqueous multi-component polyurethane according to claim 10, wherein the content of the metal catalyst compound (d) is within the range of 0.10 to 5.0 parts based on 100 parts by mass of the third component (C). Paint composition.
The aqueous multi-component polyurethane coating composition according to claim 9 or 10, wherein the metal catalyst compound (d) contains a tin compound.
The aqueous composition according to claim 9 or 10, wherein the content of the metal catalyst compound (d) is within the range of 0.01 to 1.00 parts by mass based on 100 parts by mass of nonvolatile content of the polyisocyanate component (b1). Multi-component polyurethane coating composition.
2. The organic solvent (b2) contains a compound having a boiling point of 140° C. or more and 180° C. or less and a water solubility at 20° C. of 1.0 g/100 g H 2 O or more and 20 g/100 g H 2 O or less. A water-based multi-component polyurethane coating composition.
Claim 1, wherein the content of the organic solvent (b2) is 40 parts by mass or more and 70 parts by mass or less based on 100 parts by mass of the total resin solid content of the first component (A) and the second component (B). The aqueous multi-component polyurethane coating composition described.
11. The organic solvent (c1) contains a compound having a boiling point of 140° C. or more and 180° C. or less and a water solubility at 20° C. of 1.0 g/100 g H 2 O or more and 20 g/100 g H 2 O or less. A water-based multi-component polyurethane coating composition.
The total content of the organic solvent (b2) contained in the second component (B) and the organic solvent (c1) contained in the third component (C) is the same as that of the resin of the first component (A) and the second component (B). The aqueous multi-component polyurethane coating composition according to claim 10, wherein the amount is 40 parts by mass or more and 70 parts by mass or less, based on 100 parts by mass of the total solid content.
The aqueous multi-component polyurethane coating composition according to claim 1, which is a transparent coating composition.
The aqueous multi-component polyurethane coating composition according to claim 1, wherein the first component (A) further contains a pigment.
A coating method for coating an object to be coated with the aqueous multi-component polyurethane coating composition according to claim 1.
The coating method according to claim 20, wherein the object to be coated is an automobile, an industrial machine, a construction machine, a railway vehicle, a large vehicle, a ship, or a building structure, or a part thereof.
The aqueous multi-component polyurethane according to claim 1 is applied onto a coating film already formed on the surface to be coated of the painted body or on a base treatment coating film in which a primer surfacer and/or base paint is applied to damaged parts of the painted body. A method for repairing a painted body by applying a paint composition.