JP6165419B2 - Aqueous two-component coating composition, ink composition, adhesive composition, and method of using the same - Google Patents

Description

  The present invention relates to a curing agent for an aqueous two-component curable resin, a composition and use thereof.

In recent years, water-based coating agents have been actively developed to reduce the amount of organic solvents used from the viewpoints of global environmental protection and occupational safety and health.
A two-component curable resin composed of a hydroxyl group-containing main component (so-called polyol) and a polyisocyanate as a curing agent can be cured at room temperature, and has excellent mechanical performance, chemical resistance, durability, etc. Because of its performance, it is widely used in various applications such as paints and adhesives. As for the two-component curable resin using such a polyisocyanate as a curing agent, currently, solvent-based products are mainstream, and water-based products have not yet spread widely except in some regions and applications. The reason for this is that in the case of a two-component curable resin using polyisocyanate as a curing agent, water-based curable resins are generally inferior in performance such as appearance, water resistance, and weather resistance compared to solvent-based ones. Also, the reaction time between the isocyanate group and the water in the water-based main agent is short, so the pot life is short. Also, when the isocyanate group reacts with water, carbon dioxide gas is generated and bubbles and pinholes are generated, resulting in deterioration of the quality of the cured resin. In some cases, and inferior drying properties.
As a polyisocyanate used as a curing agent for an aqueous two-component curable resin, for example, as described in Patent Documents 1 and 2, a hydrophilic component is included to impart compoundability to an aqueous main agent. There is.
On the other hand, as described in Patent Document 3, for example, a water-soluble or water-dispersible acrylic polyol having a specific number average molecular weight, hydroxyl value and acid value is used as a main agent, and does not contain a hydrophilic component, in other words A polyisocyanate which itself does not have dispersibility in water can also be used as a curing agent. In this case, a polyisocyanate having a low viscosity is preferable in terms of blendability with an aqueous main agent.

Japanese Patent No. 2961475 Japanese Patent No. 3491919 Japanese Patent Publication No. 8-32851

However, among the above-mentioned conventional techniques, those in which a polyisocyanate, which is a curing agent of an aqueous two-component curable resin, is provided with a hydrophilic component by adding a hydrophilic component, are themselves dispersible in water. Therefore, the water resistance and weather resistance of the coating may not be sufficient due to the influence of the hydrophilic component, although the mixing property by hand stirring with the aqueous main agent is improved to some extent.
Further, in the system using the specific acrylic polyol as the main agent, even if a polyisocyanate having a low viscosity is used as a curing agent, there is no agglomeration or clouding due to poor dispersion of the curing agent, and the cured resin has a uniform and excellent appearance. In general, thorough mixing with a stirrer is necessary to obtain the product, and it is often difficult to mix by hand stirring at the work site. Therefore, by hand stirring at the work site like a solvent-based two-component curable resin. The demand for an aqueous two-component curable resin that can provide an excellent appearance even by mixing and can exhibit excellent water resistance and weather resistance has not always been satisfied.
The present invention provides a polyisocyanate as a curing agent for an aqueous two-component curable resin, which is capable of developing an excellent appearance even when manually mixed with an aqueous main ingredient containing a hydroxyl group, and has excellent water resistance and weather resistance. The purpose is to provide.

As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that a curing agent having a specific structure and viscosity is excellent in appearance even when manually mixed with an aqueous main ingredient containing a hydroxyl group, and has water resistance. The present inventors have found that it is possible to form a cured resin excellent in heat resistance and weather resistance.
That is, the present invention is as follows.
[1] A curing agent for an aqueous two-component curable resin containing a polyisocyanate derived from an aliphatic diisocyanate,
The ratio of the 6-membered ring structure by the trimerization reaction of isocyanate to the total amount of the isocyanate group-derived structure is 50 mol% or more, and the total ratio of the uretdione structure and the allophanate structure is 20 mol% or more and 50 mol% or less,
A curing agent for an aqueous two-component curable resin, having a viscosity at 25 ° C of 150 mPa · s to 800 mPa · s.
[2] The curing agent for an aqueous two-component curable resin according to [1], wherein the six-membered ring structure is an isocyanurate ring.
[3] The curing agent for aqueous two-component curable resin according to [1] or [2], wherein the uretdione structure is 15 mol% or more and 30 mol% or less.
[4] The curing agent for an aqueous two-component curable resin according to any one of [1] to [3], wherein the allophanate structure is 5 mol% or more and 20 mol% or less.
[5] An aqueous two-component coating composition comprising a polyol dispersed or emulsified in water and the curing agent according to any one of [1] to [4].
[6] A film formed from the coating agent composition according to [5].
[7] An article coated with the coating composition according to [5].
[8] An aqueous two-component ink composition comprising a polyol dispersed or emulsified in water and the curing agent according to any one of [1] to [4].
[9] An aqueous two-component adhesive composition comprising a polyol dispersed or emulsified in water and the curing agent according to any one of [1] to [4].
[10] A method for coating an article, in which a polyol dispersed or emulsified in water and the curing agent according to any one of the above [1] to [4] are mixed by hand stirring and then coated on the article.

  The curing agent for an aqueous two-component curable resin of the present invention can form a cured resin composition that is excellent in appearance and excellent in water resistance and weather resistance even when mixed with an aqueous main ingredient containing a hydroxyl group by hand stirring. it can.

Hereinafter, a mode for carrying out the present invention (hereinafter referred to as “the present embodiment”) will be described in detail.
In addition, this invention is not restrict | limited to the following embodiment, A various deformation | transformation can be implemented within the range of the summary.

<Hardener for aqueous two-component curable resin>
The curing agent for an aqueous two-component curable resin of the present embodiment includes a polyisocyanate derived from an aliphatic diisocyanate, and a structure derived from an isocyanate group includes a 6-membered ring structure by a trimerization reaction of an isocyanate group, and an allophanate structure. And / or having a uretdione structure.
The specific structure of the curing agent for an aqueous two-component curable resin of the present embodiment is not particularly limited. For example, (a) the 6-membered ring structure, the allophanate structure and / or the uretdione structure are included in one molecule. A polyisocyanate, (b) a composition comprising a polyisocyanate having the 6-membered ring structure in one molecule and a polyisocyanate having an allophanate structure and / or a uretdione structure in one molecule, and the polyisocyanate of (a) The composition of (b) is included.
The aliphatic diisocyanate does not contain a benzene ring in its structure, and preferably has 4 to 30 carbon atoms. For example, tetramethylene-1,4-diisocyanate, pentamethylene 1,5-diisocyanate, and hexamethylene diisocyanate can be used. Hexamethylene diisocyanate is preferable from the viewpoint of heat resistance.

The curing agent for an aqueous two-component curable resin of the present embodiment is a six-membered ring in the structure derived from an isocyanate group, excluding unreacted aliphatic diisocyanate (hereinafter sometimes referred to as unreacted monomer). The structure is 50 mol% or more, and the total of the uretdione structure and the allophanate structure is 20 mol% or more and 50 mol% or less.
The ratio of each structure in the curing agent can be determined by ¹³ C-NMR measurement. Specifically, measurement of ¹³ C-NMR using BiospinAvance600 (trade name) manufactured by Bruker (measurement solvent: chloroform-d, sample concentration: 60 wt / volume%, observation frequency: 150 MHz, integration frequency: 10,000 times) When the aliphatic diisocyanate is hexamethylene diisocyanate, the signal of the carbon atom of the 6-membered ring carbonyl group is around 148.6 ppm for the isocyanurate group, and the 6-membered ring is around 135.5 ppm for the iminooxadiazinedione group. The signal of the carbon atom of the inner imino group is the signal of the carbon atom of the allophanate group-derived carbonyl group around 154.0 ppm, and the signal of the carbon atom of the 4-membered ring carbonyl group is around 157.3 ppm of the uretdione group. Is recognized. For isocyanurate groups, there are three identical carbon atoms in the structure, so 1/3 of the integrated value is obtained, for iminooxadiazinedione groups, the integrated value itself is relative to the allophanate group. The value of the integral value itself, and for the uretdione group, there are two identical carbon atoms in the structure, so half the value of the integral value corresponds to mol% of each structure. For signals derived from other structures such as urea structure, biuret structure, urethane structure, etc., the integrated value of the carbon atom signal of the carbonyl group in the structure is the number of carbonyl groups (1 for urea structure and urethane structure). The biuret structure is calculated using the value divided by 2).
The mol% (hereinafter sometimes referred to as a ratio) of each structure is calculated with the total of structures derived from isocyanate groups in the curing agent of the present embodiment (in a state where unreacted monomers are removed) as 100 mol%. Value. The structure derived from the isocyanate group includes, for example, a urea structure, a biuret structure, and a urethane structure in addition to the above isocyanurate structure, iminooxadiazinedione structure, uretdione structure, and allophanate structure.

(6-membered ring structure)
The hardening | curing agent of this embodiment contains the 6-membered ring structure by the trimerization reaction of isocyanate from the point of water resistance or a weather resistance. The six-membered ring structure includes an isocyanurate ring and an iminooxadiazinedione ring, and is preferably an isocyanurate ring from the viewpoint of water resistance and weather resistance of the formed cured resin composition.
The proportion of the 6-membered ring structure in the present embodiment is 50 mol% or more from the viewpoint of water resistance and weather resistance of the formed cured resin composition, and is less than 80 mol% from the viewpoint of mixing by hand stirring. It is preferable. More preferably, it is 55 mol% or more and 75 mol% or less, More preferably, it is 60 mol% or more and 70 mol% or less.

(Uretodione structure, allophanate structure)
The curing agent of this embodiment has a uretdione structure and / or an allophanate structure. The allophanate structure is generally formed by the reaction of two isocyanate groups and one alcohol, and the uretdione structure is generally formed by a dimerization reaction of isocyanate groups.
In the present embodiment, the total content of the uretdione structure and the allophanate structure in the curing agent (with the unreacted monomer removed) is preferably 20 mol% or more from the viewpoint that an excellent appearance can be expressed even by manual stirring. Is 25 mol% or more, more preferably 30 mol% or more. On the other hand, the total content of the uretdione structure and the allophanate structure is 50 mol% or less, preferably 45 mol% or less, more preferably 40 from the point that the formed cured resin composition has good water resistance and weather resistance. It is less than mol%.
In this embodiment, the uretdione structure in the curing agent (with the unreacted monomer removed) is not particularly limited, but it is 5 mol% or more from the viewpoint of water resistance and the balance between appearance and water resistance and weather resistance. It is preferably 45 mol% or less, more preferably 15 mol% or more and 30 mol% or less, from the viewpoint of balance between appearance, water resistance and weather resistance.
In the present embodiment, the allophanate structure in the curing agent (with the unreacted monomer removed) is not particularly limited, but is preferably 5 mol% or more from the viewpoint of appearance and balance between appearance and water resistance and weather resistance. Further, it is more preferably 20 mol% or less from the viewpoints of weather resistance, balance between appearance, water resistance and weather resistance.
In the present embodiment, the uretdione structure in the curing agent (with the unreacted monomer removed) is 5 mol% or more and 45 mol% or less in view of the balance between appearance, water resistance and weather resistance, and in the curing agent. The allophanate structure (with unreacted monomers removed) is preferably 5 mol% or more and 20 mol% or less, the uretdione structure is 15 mol% or more and 30 mol% or less, and the allophanate structure is 5 mol% or more. More preferably, it is 20 mol% or less.

(Other structures)
The curing agent of the present embodiment can include a urea structure, a biuret structure, and a urethane structure in addition to the six-membered ring structure, the uretdione structure, and the allophanate structure.

(Isocyanate group mass concentration)
The isocyanate group mass concentration of the curing agent of the present embodiment (with unreacted monomer removed) is not particularly limited, but is preferably 20% by weight or more from the viewpoint of mixing by hand stirring, and is formed. It is preferably 24% by weight or less from the viewpoint of water resistance and weather resistance of the resin composition.

(viscosity)
The curing agent of the present embodiment has a viscosity at 25 ° C. of 150 mPa · s or more and 800 mPa · s or less. Here, the viscosity is a value measured in the absence of a solvent or an unreacted monomer.
When the viscosity at 25 ° C. is 150 mPa · s or more, the formed cured resin composition has good water resistance and weather resistance, and is preferably 200 mPa · s or more, more preferably 250 mPa · s or more. When the viscosity is 800 mPa · s or less, the appearance of an excellent appearance by hand stirring is facilitated, preferably 600 mPa · s or less, more preferably 500 mPa · s or less.

<Method for producing curing agent for aqueous two-component curable resin>
Although the manufacturing method of the hardening | curing agent for water-system two-component type cured resins of this embodiment is not specifically limited, For example, it can manufacture with the following method.
The ratio of the 6-membered ring structure, the allophanate structure, and the uretdione structure in the aqueous two-component curing resin curing agent of the present embodiment is described in, for example, Japanese Patent No. 3395300 and International Publication No. WO2007 / 046470. It is possible to adjust based on the above method, and a specific production method is illustrated below.
The curing agent of the present embodiment is not particularly limited. For example, the isocyanuration reaction, allophanation reaction, and uretdioneization reaction are performed in the presence of an excess of an aliphatic diisocyanate (eg, hexamethylene diisocyanate) monomer, and the reaction is completed. Later, it can be produced by a method of removing unreacted diisocyanate monomer, a method of separately producing two or more polyisocyanates and then mixing them.

(Synthesis of 6-membered ring structure)
Examples of the catalyst for deriving a polyisocyanate containing a 6-membered ring structure such as an isocyanurate group from a diisocyanate monomer include generally used isocyanurate catalysts. The isocyanurate-forming catalyst is not particularly limited. For example, those having basicity are generally preferred. (1) Tetraalkylammonium hydroxides such as tetramethylammonium and tetraethylammonium, and organic weak acid salts such as acetic acid and capric acid. (2) Hydroxyalkylammonium hydroxides such as trimethylhydroxypropylammonium, trimethylhydroxyethylammonium, triethylhydroxypropylammonium and triethylhydroxyethylammonium, and organic weak acid salts such as acetic acid and capric acid; (3) Acetic acid and capron Alkali metal salts of alkyl carboxylic acids such as acid, octylic acid, myristic acid, such as tin, zinc, lead, etc .; (4) such as sodium, potassium, etc. (5) Aminosilyl group-containing compounds such as hexamethyldisilazane; (6) Mannich bases; (7) Combinations of tertiary amines and epoxy compounds; (8) Phosphorous systems such as tributylphosphine There are compounds. Of these, quaternary ammonium organic weak acid salts are preferred, and tetraalkylammonium organic weak acid salts are more preferred. Since an aminosilyl group-containing compound eventually produces polyisocyanate having a biuret group and a monoisocyanate having a urethane bond, other catalysts are preferable to the aminosilyl group-containing compound. In the isocyanuration reaction, a certain amount of iminooxadiazinedione ring may also be formed.
The amount of these catalysts is not particularly limited, but is preferably 10 to 1000 ppm with respect to the mass of the charged diisocyanate monomer. As an upper limit, it is more preferable that it is 500 ppm, More preferably, it is 100 ppm.
The isocyanuration reaction temperature is not particularly limited, but is preferably 50 ° C. or higher from the viewpoint of reactivity, preferably 120 ° C. or lower, more preferably 60 to 90 ° C. from the viewpoint of suppressing the occurrence of coloring.
The isocyanuration reaction is carried out after the conversion rate (the mass ratio of the polyisocyanate produced by the isocyanuration reaction to the charged diisocyanate monomer) reaches a desired value, and then, for example, acidic compounds such as phosphoric acid and acidic phosphate esters Stop by adding. In order to obtain the curing agent of this embodiment, it is preferable to stop the progress of the reaction at the initial stage. However, the cyclic trimerization of the isocyanate group has a very high initial reaction rate, so it is difficult to stop the progress of the reaction at the initial stage, and the reaction conditions, particularly the addition amount and addition method of the catalyst, are carefully considered. It is preferable to select. For example, it is recommended that a catalyst addition method at regular intervals is suitable.
The conversion rate of the isocyanurate-forming reaction for obtaining a curing agent containing the 6-membered ring structure (isocyanurate, etc.) of the present embodiment in the above proportion is preferably 30% or less, more preferably 25% or less, and still more preferably 20% or less.

(Synthesis of allophanate structure)
In the curing agent of this embodiment, the allophanate structure is obtained, for example, by a reaction between an isocyanate group and an alcohol. The alcohol is not particularly limited, but methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutanol, 1-pentanol, 2-pentanol, isoamyl alcohol, 1-hexanol, 2 -Hexanol, 1-heptanol, 1-octanol, 2-ethyl-1-hexanol, 3,3,5-trimethyl-1-hexanol, tridecanol, pentadecanol, palmityl alcohol, stearyl alcohol, cyclopentanol, cyclohexanol , Methylcyclohexanol, trimethylcyclohexanol and the like. Among them, 1-propanol, isobutanol, 1-butanol, isoamyl alcohol, pentanol, 1-hexanol, 2-hexanol, 1-heptanol, 1-octanol, 2-octanol, 2-ethyl-1-hexanol, 3, 3 , 5-trimethyl-1-hexanol is preferred because the resulting polyisocyanate has a lower viscosity.
The amount of the alcohol added is preferably 1000/1 or more and 10/1 or less, more preferably 1000/1 or more and 100/1 or less, in terms of the equivalent ratio of the isocyanate group of the diisocyanate monomer to the hydroxyl group of the alcohol. When the equivalent ratio is 10/1 or less, the average value of the number of isocyanate groups contained in one molecule of polyisocyanate, that is, the so-called average number of functional groups, is preferable in that it can have a relatively large value.
In order to produce an allophanate group, an allophanate reaction catalyst is usually used. Examples of the specific compound include alkyltin salts such as tin, lead, zinc, bismuth, zirconium and zirconyl, and organic tin compounds such as tin 2-ethylhexanoate and dibutyltin dilaurate, and 2-ethylhexane. Organic lead compounds such as lead acid, organic zinc compounds such as zinc 2-ethylhexanoate, bismuth 2-ethylhexanoate, zirconium 2-ethylhexanoate, zirconyl 2-ethylhexanoate, etc. be able to. In addition, the above isocyanurate reaction catalyst can also be an allophanate reaction catalyst. When performing the allophanatization reaction using the above isocyanurate reaction catalyst, the isocyanurate group-containing polyisocyanate is naturally produced. From the viewpoint of production economy, it is preferable to use the above-described isocyanurate reaction catalyst as the allophanate reaction catalyst and to perform the allophanate reaction and the isocyanurate reaction in parallel.

(Synthesis of uretdione structure)
The uretdione structure can be obtained using, for example, a uretdione reaction catalyst. Examples of this specific compound are tertiary phosphines such as trialkylphosphine such as tri-n-butylphosphine and tri-n-octylphosphine, and tris (dialkylamino) phosphine such as tris- (dimethylamino) phosphine. And cycloalkylphosphine such as cyclohexyl-di-n-hexylphosphine. Many of these compounds simultaneously promote the isocyanuration reaction and produce isocyanurate group-containing polyisocyanates in addition to uretdione group-containing polyisocyanates. When the desired conversion rate is reached, it is preferable to stop the uretdioneization reaction by adding a deactivator for the uretdioneization reaction catalyst such as phosphoric acid or methyl paratoluenesulfonate.
Moreover, a uretdione structure can also be obtained by heating the monomer of a diisocyanate, without using the above catalysts. The heating temperature is preferably 120 ° C. or higher, more preferably 130 to 170 ° C., further preferably 140 to 160 ° C., and the heating time is preferably 0.5 to 4 hours, more preferably 1 -3 hours, more preferably 1-2 hours.
In order to obtain the curing agent of the present embodiment, without using a uretdioneation reaction catalyst, following the above-described isocyanuration reaction and allophanation reaction, the uretdioneation reaction by heating alone is advanced, and after the completion of the reaction, an unreacted diisocyanate monomer It is advantageous to remove the because the manufacturing process can be simplified. It is surprising that the increase in the diisocyanate monomer concentration is suppressed when the curing agent obtained by this method is stored for a long time.
Removal of the unreacted disoisocyanate monomer from the reaction solution after completion of the reaction can be performed by thin film distillation or extraction, and the curing agent of this embodiment can be obtained.

<Aqueous two-component curable resin composition>
The curing agent of this embodiment can be used as an aqueous two-component curable resin composition by combining with an aqueous main agent. Such a resin composition includes an aqueous two-component coating agent composition, an aqueous two-component ink composition, and an aqueous two-component adhesive composition.

(Aqueous base)
The main component for the aqueous two-component curable resin in the resin composition of the present embodiment is not particularly limited, and is a resin dispersed or emulsified in a medium containing water as a main component and optionally containing a small amount of an organic solvent. Is used. The design of the resin composition, glass transition temperature, particle diameter, molecular weight, and hydroxyl group concentration varies depending on the use and purpose of the cured resin composition, and many products are commercially available. Regarding the composition, acrylic, polyester, polyurethane and the like can be used. In some cases, a composite of them can also be used.
The glass transition temperature of the resin varies depending on the use and purpose of the cured resin composition, and is not limited. Generally, however, the hardness of the hard paint such as an adhesive or an elastic paint is reduced to a low value in applications requiring flexibility. Although it is set to a high value in the required application, it is usually about -50 ° C to 80 ° C.
The particle diameter of the resin is usually set to approximately 50 nm to 400 nm as an average particle diameter from the viewpoint of dispersion stability and viscosity and various performances of the formed cured resin composition. About the compoundability with the main ingredient by stirring, 200 nm or less is preferable.
The molecular weight of the resin is preferably 5000 or more and 20000 or less as the number average molecular weight in the acrylic system and 500 as the number average molecular weight in the polyester system from the viewpoint of blendability with the main agent by hand stirring and the performance of the cured resin composition in the present invention. The number average molecular weight is preferably 10,000 or more and 100,000 or less in the polyurethane system.
The hydroxyl group concentration of the resin is appropriately set depending on the application and purpose, but is usually about 0.5% or more and 5% or less as the weight% of the hydroxyl group in the resin component.
Acrylic resin is obtained by copolymerizing an ethylenically unsaturated bond-containing monomer having a hydroxyl group alone or a mixture thereof with another ethylenically unsaturated bond-containing monomer copolymerizable therewith. Is obtained. Polymerization is carried out by general solution polymerization or emulsion polymerization, and a chain transfer agent such as mercaptans is used to adjust the molecular weight. In the case of emulsion polymerization, a resin emulsified in water can be obtained directly, but in the case of solution polymerization, it is necessary to copolymerize an amount of a carboxyl group-containing monomer necessary for water dispersion performed after polymerization. After completion of the polymerization, the carboxyl group is neutralized with a basic compound such as ammonia or amine, and water is added to obtain an aqueous dispersion of polyol. Preferably, the organic solvent used during the solution polymerization is then removed by distillation. Examples of the ethylenically unsaturated bond-containing monomer having a hydroxyl group include 2-hydroxyethyl acrylate, 3-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 2-hydroxyethyl methacrylate, Examples include methacrylic acid-3-hydroxypropyl, methacrylic acid-4-hydroxybutyl, and the like. Preferred are 2-hydroxyethyl acrylate and 2-hydroxyethyl methacrylate. Other ethylenically unsaturated bond-containing monomers copolymerizable with the above monomers include ethyl acrylate, propyl acrylate, isopropyl acrylate, acrylic acid-n-butyl, acrylic acid isobutyl, acrylic acid-n -Acrylic esters such as hexyl, cyclohexyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, etc .; methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, -n-butyl methacrylate, isobutyl methacrylate Methacrylic acid esters such as acrylic acid, methacrylic acid, maleic acid and itaconic acid; acrylic acid, methacrylic acid-n-hexyl, cyclohexyl methacrylate, methacrylic acid-2-ethylhexyl, lauryl methacrylate; , Methacrylamide, N, N-methylenebisacrylamide, diacetone acrylamide, etc .; glycidyl group-containing monomers such as glycidyl methacrylate; vinyls such as styrene, vinyl toluene, vinyl acetate, acrylonitrile, dibutyl fumarate Monomer; Hydrolyzable silyl group-containing monomers such as vinyltrimethoxysilane, vinylmethyldimethoxysilane, and γ- (meth) acryloxypropyltrimethoxysilane.
The polyester-based resin is, for example, a dibasic acid alone or a mixture selected from the group of carboxylic acids such as succinic acid, adipic acid, sebacic acid, dimer acid, maleic anhydride, phthalic anhydride, isophthalic acid, terephthalic acid, and the like. If necessary, a polycarboxylic acid containing a sulfonate and a polyvalent acid selected from the group of ethylene glycol, propylene glycol, butylene glycol, hexylene glycol, diethylene glycol, neopentyl glycol, trimethylolpropane, pentaerythritol, glycerin, etc. It can be obtained by condensation reaction with an alcohol or the like alone or by a mixture, or by ring-opening polymerization of ε-caprolactone using a polyhydric alcohol, for example. The molecular weight is adjusted by adjusting the degree of polymerization. An aqueous dispersion of polyol can be obtained by adding water after neutralization of the carboxyl group in the polyol with a basic compound such as ammonia or amine after completion of the polymerization. When an organic solvent is used for polymerization or water dispersion, the organic solvent is preferably removed by distillation after water dispersion.
As the polyurethane-based resin, what is generally called a polyurethane dispersion is used. For example, a reaction between a diisocyanate compound such as isophorone diisocyanate, hexamethylene diisocyanate, methylene diphenyl diisocyanate, hydrogenated methylene diphenyl diisocyanate, and polyester diol or polycarbonate diol. The prepolymerization reaction is carried out in the presence of a necessary amount of a carboxyl group-containing diol such as dimethylolpropionic acid, neutralized with a tertiary amine, etc., and then water-dispersed by adding water, It can be obtained by quickly adding a diamine compound such as ethylenediamine or isophoronediamine to carry out chain elongation. The molecular weight is adjusted depending on the ratio of isocyanate groups to hydroxyl groups during the prepolymerization reaction and the conditions of chain extension. When an organic solvent is used in the prepolymerization reaction, the organic solvent is preferably removed by distillation after chain extension. In addition, since the polyurethane dispersion itself is a tough resin, the main component for the aqueous two-component curable resin in the present embodiment has a hydroxyl group in addition to the one having a predetermined amount of hydroxyl group introduced therein. Even when it has, it can use what has a small hydroxyl group content.

(Method for producing aqueous two-component curable resin composition)
In the production of the water-based two-component curable resin composition in the present embodiment, it is preferable that the ratio of isocyanate groups to hydroxyl groups is performed under an excess of isocyanate groups in consideration of the reaction of isocyanate groups with water in the curing agent. Usually, the molar ratio of isocyanate groups to hydroxyl groups is set to 1.1 to 1.5 times. In addition, it is preferable to dilute the curing agent in advance with an organic solvent that does not have reactivity with the isocyanate group because of the effect of improving the compoundability with the aqueous main agent by hand stirring. As an organic solvent that can be used for dilution, ethylene glycol monobutyl ether acetate, butyl acetate, propylene glycol monomethyl ether acetate, diethylene glycol diethyl ether, dipropylene glycol dimethyl ether, butyl carbitol acetate, etc. are used alone or in combination. Can do. Among them, ethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, diethylene glycol diethyl ether, and dipropylene glycol dimethyl ether are highly effective in improving the appearance of the cured resin composition formed by hand stirring, and drying the cured resin composition. It is preferable because of its excellent properties. However, from the viewpoints of global environmental protection and occupational safety and health, it is desirable to reduce the amount of these organic solvents as much as possible. The amount of organic solvent used for dilution is 50% by mass based on the total amount with the curing agent. The following is preferable. In addition, in order to improve the appearance of the cured resin composition by hand stirring, a so-called water-dispersible polyisocyanate containing a hydrophilic group can be mixed in advance with the curing agent of the present embodiment. From the viewpoint of water resistance and weather resistance of the cured resin composition, it is preferably 50% by mass or less based on the total amount with the curing agent of the present embodiment. Even when such a water-dispersible polyisocyanate is mixed, it can be diluted in advance with the above-mentioned organic solvent in order to reduce the viscosity and improve the convenience in handling. In this case as well, it is desirable to reduce the amount of the organic solvent used as much as possible. The amount of the organic solvent used for dilution is 30% by mass or less based on the total amount of the curing agent of the present embodiment and the water-dispersible polyisocyanate. Preferably there is.

The production of the cured resin composition can be carried out by hand stirring, but if possible at the work site, using a stirrer can reduce the blending time and the amount of organic solvent for diluting the curing agent. preferable. The time required for blending is usually about 1 to 10 minutes, depending on the blending method.
In producing the cured resin composition, if necessary, for example, a curing accelerator such as an organometallic compound such as carboxylic acid such as tin, zinc and lead, an antioxidant such as hindered phenol, such as benzotriazole and benzophenone. UV stabilizers such as hindered amines, light stabilizers such as titanium oxide, carbon black, indigo, quinacridone, pearl mica, aluminum paste and other pigments, other rheology control agents, leveling agents, dispersants, antifoaming agents, etc. Additives can be blended.

The composition of this embodiment includes automobiles, buses, railway vehicles, construction machinery, agricultural machinery, floors and walls and roofs of buildings, metal products, mortar and concrete products, woodwork products, plastic products, calcium silicate boards and gypsum boards It can be used in the fields of water-based two-component coating agents, water-based two-component inks and adhesives for ceramic building materials. Among them, it can be preferably used as an aqueous two-component coating agent, and general methods such as spray coating, roller coating, curtain flow coating, air knife coating, gravure coating, and brush coating can be used. In the field of aqueous two-component coating agents, acrylic, polyester, and polyurethane main agents are preferably used, and in the field of aqueous two-component adhesives, acrylic and polyurethane main agents are preferably used.
The aqueous two-component curable resin composition in the present embodiment has a relatively long pot life, but after production, it varies depending on the ambient temperature, but is used for about 1 to 3 hours. It is preferable to do. Moreover, drying can be performed by natural drying, and heat drying with warm air or infrared rays is also possible.

The coating composition can be applied to an object by a general method such as spray coating, roller coating, curtain flow coating, air knife coating, gravure coating, or brush coating to form a coating film.
Although the film of this embodiment is not particularly limited, curing proceeds gradually after formation.

EXAMPLES Hereinafter, although this invention is demonstrated using an Example and a comparative example, this invention is not limited to a following example. In the examples and comparative examples, “parts” means “parts by weight” unless otherwise specified.
First, measurement methods and evaluation methods performed in Examples and Comparative Examples are shown below.

〔Measuring method〕
(Measurement of viscosity of curing agent)
Using a viscometer (RE-85R (trade name) manufactured by Toki Sangyo Co., Ltd.), those with a viscosity of about 500 mPa · s or less at 25 ° C. are rotated at 20 rpm, and those with a viscosity of about 500 mPa · s or more are rotated. It was measured at several tens of rpm.

(Structure measurement of curing agent)
Isocyanurate in measurement of ¹³ C-NMR using Biospin Avance 600 (trade name) manufactured by Bruker (measurement solvent: chloroform-d, sample concentration: 60 wt / volume%, observation frequency: 150 MHz, integration number: 10,000 times) Integrated value of peaks derived from groups (around 148.6 ppm), iminooxadiazinedione groups (around 135.5 ppm), allophanate groups (around 154.0 ppm), uretdione groups (around 157.3 ppm), and other structures More calculated.

(Measurement of isocyanurate conversion rate)
The relationship between the conversion rate and the refractive index of the reaction solution was obtained in advance, and the measurement was performed by measuring the refractive index of the reaction solution.
The refractive index was measured with a Refractometer RA-620 (trade name) manufactured by Kyoto Electronics Industry Co., Ltd.

(Measurement of isocyanate group mass concentration)
The measurement of the isocyanate group concentration was carried out according to the method described in JIS K7301-1995 (Test method for tolylene diisocyanate type prepolymer for thermosetting urethane elastomer).
A specific method is shown below.
1) 1 g of a sample was taken in a 200 ml Erlenmeyer flask and 20 ml of toluene was added and dissolved.
2) Then, 20 ml of 2.0N di-n-butylamine / toluene solution was added and allowed to stand for 15 minutes.
3) 70 ml of 2-propanol was added and dissolved.
4) Titration was performed using 1 mol / l hydrochloric acid, and the isocyanate group mass concentration was measured.
5) Even when the sample was not added, the measurement was performed in the same manner as described above.

(Measurement of number average molecular weight)
For the number average molecular weight, the polystyrene-based number average molecular weight was measured by gel permeation chromatograph (GPC) measurement using the following apparatus and conditions.
Device: HLC-8120GPC (trade name) manufactured by Tosoh Corporation
Column: Tosoh Co., Ltd. TSKgelSuperH1000 (trade name) x 1, TSKgel Super H2000 (trade name) x 1, TSKgel SuperH3000 (trade name) x 1,
Carrier: Tetrahydrofuran,
Detection method: Differential refractometer

(Measurement of solid content)
About 1 g of a sample was precisely weighed in an aluminum cup weighing about 1 g and heated in a dryer at 105 ° C. for 3 hours. After cooling to room temperature, the weight was accurately weighed again, and the weight% of the dry residue in the sample was taken as the solid content.

〔Evaluation method〕
(Appearance evaluation of coating composition)
Spray coating of commercially available solvent-based two-component acrylic urethane white enamel on aluminum plate in advance, drying after setting for 2 hours at 80 ° C, curing for at least 2 weeks at room temperature, until 60 ° gloss value is less than 10% A substrate whose surface was polished with # 1000 sandpaper was prepared. The substrate was coated with an air spray so that the dry film thickness was about 40 microns, and dried for 7 days in an atmosphere of 23 ° C./50% RH. Thereafter, a gloss value of 60 degrees was measured under the conditions of JIS Z8741 using a gloss meter (digital variable angle gloss meter UDV-6P (trade name) manufactured by Suga Test Instruments Co., Ltd.).
The 60 ° gloss value was evaluated as ○ when 90% or more, △ when less than 90% and 80% or more, and × when less than 80%.

(Water resistance evaluation of coating composition)
The film was coated on a polypropylene plate using an air spray so that the dry film thickness was about 40 microns, and dried for 7 days in an atmosphere of 23 ° C./50% RH. The peeled film was cut into approximately 4cm x 4cm, weighed precisely, soaked in water at 40 ° C for 24 hours, then removed from the water, wiped off the water adhering to the surface, and then quickly weighted. Weighing and measuring the weight increase rate.
A weight increase rate of less than 2% was evaluated as ◯, 2% or more and less than 5% as Δ, and 5% or more as X.

(Evaluation of weather resistance of coating agent composition)
Spray coating of commercially available solvent-based two-component acrylic urethane white enamel on aluminum plate in advance, drying after setting for 2 hours at 80 ° C, curing for at least 2 weeks at room temperature, until 60 ° gloss value is less than 10% A substrate whose surface was polished with # 1000 sandpaper was prepared. The substrate was coated with an air spray so that the dry film thickness was about 40 microns, and dried for 7 days in an atmosphere of 23 ° C./50% RH. Thereafter, using a Super Xenon Weather Meter SX75 manufactured by Suga Test Instruments Co., Ltd., the 60 degree gloss retention after exposure for 2500 hours under the conditions of JIS K5600-7-7 is 80% or higher, and less than 80% is 70% or higher. Was evaluated as Δ, and less than 70% was evaluated as ×.

[Example 1 (Production of curing agent)]
A four-necked flask equipped with a stirrer, thermometer, reflux condenser, nitrogen blowing tube, and dropping funnel was placed in a nitrogen atmosphere, and 600 parts of hexamethylene diisocyanate and 2.5 parts of isobutanol were charged. At 80 ° C. for 2 hours. Thereafter, 0.5 part of a solution obtained by diluting the isocyanurate-forming catalyst trimethyl-2-methyl-2-hydroxyethylammonium hydroxide with isobutanol to 5% by mass was added to carry out an isocyanuration reaction. %, 0.06 part of 85% aqueous phosphoric acid solution was added to stop the reaction. Thereafter, the reaction solution was further maintained at 160 ° C. for 1 hour. This heating produced uretdione group-containing polyisocyanate. The reaction solution was cooled to room temperature, filtered, and unreacted hexamethylene diisocyanate was removed using a thin film distillation apparatus. The resulting curing agent has a 6-membered ring structure of 63.4 mol% (isocyanurate ring 61.1%, iminooxadiazinedione structure 2.3%), uretdione structure 22.5 mol%, allophanate The structure was 13.6 mol%, the other structures were 0.5 mol%, the isocyanate group mass concentration was 23.1%, and the viscosity was 280 mPa · s.

[Example 2 (Production of curing agent)]
The same procedure as in Example 1 was performed except that 1.1 parts of isobutanol was added. The resulting curing agent has a 6-membered ring structure of 65.9 mol% (isocyanurate ring 63.5%, iminooxadiazinedione structure 2.4%), uretdione structure 26.5 mol%, allophanate The structure was 7.3 mol%, the other structures were 0.3 mol%, the isocyanate group mass concentration was 23.2%, and the viscosity was 400 mPa · s.

[Example 3 (Production of curing agent)]
The same procedure as in Example 1 was conducted except that 3.7 parts of isobutanol was added. The resulting curing agent has a 6-membered ring structure of 58.1 mol% (isocyanurate ring 57.2%, iminooxadiazinedione structure 0.9%), uretdione structure 19.2 mol%, allophanate. The structure was 22.3 mol%, the other structures were 0.4 mol%, the isocyanate group mass concentration was 22.8%, and the viscosity was 240 mPa · s.

[Example 4 (Production of curing agent)]
It implemented like Example 1 except having changed the heating conditions after adding phosphoric acid and stopping reaction to 160 degreeC and 0.5 hour. The structure of the obtained curing agent was 71.8 mol% of 6-membered ring structure (69.2% of isocyanurate ring, 2.6% of iminooxadiazinedione structure), 12.2 mol% of uretdione structure, and allophanate. The structure was 15.8 mol%, the other structures were 0.2 mol%, the isocyanate group mass concentration was 23.1%, and the viscosity was 350 mPa · s.

[Example 5 (Production of curing agent)]
The same procedure as in Example 1 was performed except that 0.7 part of isobutanol was added and the conversion rate was 20%. The resulting curing agent has a 6-membered ring structure of 74.2 mol% (isocyanurate ring 71.6%, iminooxadiazinedione structure 2.6%), uretdione structure 21.6 mol%, and allophanate. The structure was 4.0 mol%, the other structures were 0.2 mol%, the isocyanate group mass concentration was 23.1%, and the viscosity was 480 mPa · s.

[ Reference Example 1 (Production of curing agent)]
The inside of the apparatus similar to Example 1 was made into nitrogen atmosphere, 1000 parts of hexamethylene diisocyanate and 30 parts of 2-ethylhexanol were prepared, and the temperature inside the reactor was maintained at 90 ° C. for 1 hour with stirring to conduct a urethanization reaction. Thereto was added 0.6 part of a 5% isobutanol solution of tetramethylammonium capryate as an allophanate / isocyanurate catalyst. When the isocyanate group mass concentration of the reaction solution reached 43.5%, 0.06 part of an 85% aqueous solution of phosphoric acid was added to stop the reaction. The reaction solution was cooled to room temperature, filtered, and unreacted hexamethylene diisocyanate was removed using a thin film distillation apparatus. The structure of the obtained curing agent is 53.3 mol% of 6-membered ring structure (52.5% of isocyanurate ring, 0.8% of iminooxadiazinedione structure), 43.1 mol% of allophanate structure, etc. The structure was 3.6 mol%, the isocyanate group mass concentration was 20.3%, and the viscosity was 350 mPa · s.

[Comparative Example 1 (Production of curing agent)]
The inside of the apparatus similar to Example 1 was made into nitrogen atmosphere, 600 parts of hexamethylene diisocyanate was prepared, and the reactor internal temperature was kept at 60 ° C. with stirring. 9 parts of tri-n-butylphosphine (Cytop (trademark) 340, Cytec), which is a uretdione reaction catalyst, was added thereto, and uretdione reaction and isocyanurate reaction were carried out. When the conversion rate reached 40%. The reaction was stopped by adding 12 parts of methyl-p-toluenesulfonate. The reaction solution was cooled to room temperature, filtered, and unreacted hexamethylene diisocyanate was removed using a thin film distillation apparatus. The resulting curing agent has a 6-membered ring structure of 19.7 mol% (isocyanurate ring 13.8%, iminooxadiazinedione structure 5.9%), uretdione structure 64.3 mol%, allophanate. The structure was 9.0 mol%, the other structures were 7.0 mol%, the isocyanate group mass concentration was 22.1%, and the viscosity was 150 mPa · s.

[Comparative Example 2 (Production of curing agent)]
The same procedure as in Example 1 was performed except that 0.7 part of isobutanol was added and the addition rate was 24%. The resulting curing agent has a 6-membered ring structure of 74.7 mol% (isocyanurate ring 72.1%, iminooxadiazinedione structure 2.6%), uretdione structure 20.0 mol%, allophanate The structure was 3.8 mol%, the other structures were 1.5 mol%, the isocyanate group mass concentration was 22.7%, and the viscosity was 1010 mPa · s.

[Comparative Example 3 (Production of curing agent)]
The inside of the apparatus similar to Example 1 is made into nitrogen atmosphere, 1200 parts of hexamethylene diisocyanate and 93 parts of 2-ethyl-1-hexanol are prepared, and the temperature in the reactor is kept at 90 ° C. for 1 hour with stirring to carry out the urethanization reaction. I did it. After raising the temperature in the reactor to 130 ° C., 0.29 parts of 20% mineral spirit solution of zirconium 2-ethylhexanoate as an allophanatization catalyst was added and reacted for 1 hour. The reaction was stopped by adding 0.011 part of 50% isobutanol solution. The reaction solution was cooled, filtered, and unreacted HDI was removed using a thin film evaporator. The resulting curing agent has a 6-membered ring structure of 2.8 mol% (2.8% isocyanurate ring, no iminooxadiazinedione structure), a uretdione structure of 7.6 mol%, and an allophanate structure of 86. It was 0.4 mol%, the other structure was 3.2 mol%, the isocyanate group mass concentration was 17.2%, and the viscosity was 110 mPa · s.

[Production Example 1 (Production of acrylic polyol aqueous dispersion)]
A four-necked separable flask equipped with a stirrer, thermometer, reflux condenser, nitrogen blowing tube, and dropping funnel was placed in a nitrogen atmosphere, charged with 300 parts of ethylene glycol monobutyl ether, and the reactor temperature was 80 under stirring. Held at 0C. There, 146.3 parts of methyl methacrylate as a monomer, 105 parts of styrene, 257.6 parts of acrylic acid-n-butyl, 14 parts of methacrylic acid, 177.1 parts of methacrylic acid-2-hydroxyethyl, 2 as a polymerization initiator 2,2'-azobisisobutyronitrile and 0.3 part of n-dodecyl mercaptan as a chain transfer agent were uniformly mixed at a constant rate over a period of 4.5 hours. Thereafter, the reactor internal temperature was maintained at 80 ° C. for 2 hours. Thereafter, the mixture was cooled, 11.6 parts of a 25% aqueous ammonia solution was added, and the mixture was stirred for 15 minutes. Further, 1300 parts of ion-exchanged water was added with stirring to obtain an aqueous dispersion, and the mixture was concentrated using a rotary evaporator until the solid content became about 45% by weight. Thereafter, the pH was adjusted to 8.0 with a 25% aqueous ammonia solution to obtain an aqueous dispersion of an acrylic polyol. The obtained water dispersion had an average particle diameter of 90 nm, the hydroxyl group concentration of the polyol resin was 3.3% by weight calculated from the raw materials charged, and the number average molecular weight was 9,600.

[Example 7 (Production of aqueous two-component coating agent composition)]
40 g of the polyol aqueous dispersion produced in Production Example 1 was weighed into a container, 0.15 g of leveling agent Byk348 and 0.19 g of TegoWet 270 were added, and the mixture was stirred for 1 minute with a spoon. To this, 3.2 g of a mixture of Dispersbyk 19237.5 parts of dispersant and 62.5 parts of propylene glycol-n-propyl ether was added and stirred with a spoonful for 1 minute. As a curing agent component, 72.5 parts of the curing agent prepared in Example 1 was previously mixed with 27.5 parts of ethylene glycol monobutyl ether acetate as a diluent solvent, and the molar ratio of isocyanate group to hydroxyl group was A coating composition was prepared by adding NCO / OH = 1.2 (10.5 g) and stirring with a spoonful for 10 minutes.

[Example 8 (Preparation of aqueous two-component coating composition)]
A coating agent composition was prepared in the same manner as in Example 7 except that the curing agent used in Example 2 was used.

[Example 9 (Preparation of aqueous two-component coating composition)]
A coating agent composition was prepared in the same manner as in Example 7 except that the hardener prepared in Example 3 was used.

[Example 10 (Production of aqueous two-component coating agent)]
A coating agent was prepared in the same manner as in Example 7 except that the hardener prepared in Example 4 was used.

[Example 11 (Preparation of aqueous two-component coating agent composition)]
A coating agent composition was prepared in the same manner as in Example 7 except that the hardener prepared in Example 5 was used.

[ Reference Example 2 ( Preparation of aqueous two-component coating composition)]
A coating agent composition was prepared in the same manner as in Example 7 except that the hardener prepared in Reference Example 1 was used.

[Comparative Example 4 (Preparation of aqueous two-component coating composition)]
A coating agent composition was prepared in the same manner as in Example 7 except that the curing agent prepared in Comparative Example 1 was used.

[Comparative Example 5 (Preparation of aqueous two-component coating composition)]
A coating agent composition was prepared in the same manner as in Example 7 except that the hardener prepared in Comparative Example 2 was used.

[Comparative Example 6 (Preparation of aqueous two-component coating composition)]
A coating agent composition was prepared in the same manner as in Example 7 except that the hardener prepared in Comparative Example 3 was used.

(Evaluation of coating agent composition)
The coating agent compositions prepared in Examples 7 to 12 and Comparative Examples 4 to 6 were prepared with Ford Cup No. 4 is used to adjust the viscosity with ion-exchanged water so that it is 18 seconds to 22 seconds, and is applied by air spray so that the dry film thickness is about 40 microns. And the weather resistance were evaluated. The results are summarized in Table 1.

  The curing agent of the present invention is useful for an aqueous two-component curable resin, and a composition using the curing agent and a coating method using the same are used for automobiles, buses, railway vehicles, building machines, agricultural machines, and buildings. Water-based two-component coating agent, water-based two-component ink and viscosity for floors, walls and roofs, metal products, mortar and concrete products, woodwork products, plastic products, ceramic building materials such as calcium silicate boards and gypsum boards It can be suitably used in the field of adhesives.

Claims (7)

A polyol dispersed or emulsified in water;
A curing agent for an aqueous two-component curable resin containing a polyisocyanate derived from an aliphatic diisocyanate,
The ratio of the 6-membered ring structure resulting from the trimerization reaction of the isocyanate group to the total amount of the isocyanate group-derived structure is 55 mol% to 80 mol%, and the total ratio of the uretdione structure and the allophanate structure is 20 mol% to 45 mol%. And
Ri viscosity der less 150 mPa · s or higher 800 mPa · s at 25 ° C., and an aqueous two-component type curable resin curing agent containing no hydrophilic component,
Aqueous 2-component coating composition comprising a.   The aqueous two-component coating composition according to claim 1, wherein the six-membered ring structure is an isocyanurate ring.   The aqueous two-component coating composition according to claim 1 or 2, wherein the uretdione structure is 15 mol% or more and 30 mol% or less.   The aqueous two-component coating composition according to any one of claims 1 to 3, wherein the allophanate structure is 5 mol% or more and 20 mol% or less. A polyol dispersed or emulsified in water;
A curing agent for an aqueous two-component curable resin containing a polyisocyanate derived from an aliphatic diisocyanate,
The ratio of the 6-membered ring structure resulting from the trimerization reaction of the isocyanate group to the total amount of the isocyanate group-derived structure is 55 mol% to 80 mol%, and the total ratio of the uretdione structure and the allophanate structure is 20 mol% to 45 mol%. And
Ri viscosity der less 150 mPa · s or higher 800 mPa · s at 25 ° C., and an aqueous two-component type curable resin curing agent containing no hydrophilic component,
Aqueous 2-component ink composition comprising a. A polyol dispersed or emulsified in water;
A curing agent for an aqueous two-component curable resin containing a polyisocyanate derived from an aliphatic diisocyanate,
The ratio of the 6-membered ring structure resulting from the trimerization reaction of the isocyanate group to the total amount of the isocyanate group-derived structure is 55 mol% to 80 mol%, and the total ratio of the uretdione structure and the allophanate structure is 20 mol% to 45 mol%. And
Ri viscosity der less 150 mPa · s or higher 800 mPa · s at 25 ° C., and an aqueous two-component type curable resin curing agent containing no hydrophilic component,
Aqueous 2-component adhesive composition consisting of. A polyol dispersed or emulsified in water;
A curing agent for an aqueous two-component curable resin containing a polyisocyanate derived from an aliphatic diisocyanate,
The ratio of the 6-membered ring structure resulting from the trimerization reaction of the isocyanate group to the total amount of the isocyanate group-derived structure is 55 mol% to 80 mol%, and the total ratio of the uretdione structure and the allophanate structure is 20 mol% to 45 mol%. And
Ri viscosity der less 150 mPa · s or higher 800 mPa · s at 25 ° C., and an aqueous two-component type curable resin curing agent containing no hydrophilic component,
The article is coated by hand stirring and then coated on the article .