JP6014903B2 - Two-component aqueous one-coat paint composition - Google Patents

Description

  The present invention relates to a novel two-component water-based one-coat coating composition that can be used in various fields, particularly in the field of automotive parts coating.

  In general, in the field of paints, water-based paints are being studied to reduce the amount of organic solvent contained in paints. For paints used on synthetic resin substrates, for example, Patent Document 1 discloses that A water-dispersible resin, a water-soluble resin, a core / shell type emulsion resin, a melamine resin, a water-dispersible urethane resin, a urethane-associative thickener, and a lacquer-type aqueous base paint containing a pigment An ABS substrate having a coating step (step 1) and a step (step 2) of applying a two-component curable top clear coating containing an acrylic polyol resin and a polyisocyanate group-containing compound on the substrate subjected to step 1 A coating method is disclosed.

  On the other hand, the method of baking at the same time after coating a plurality of layers as in the 2-coat 1-bake method has a problem in that the number of coating steps is large and the cost is high. As a paint for solving such problems, a one-coat paint that is applied by a one-coat one-bake method without applying a clear coat is known. For example, Patent Document 2 discloses a reaction product of a polyhydric alcohol and a polybasic acid, wherein the polyhydric alcohol and the polybasic acid have a component having an alicyclic structure in at least a part of the component constituting the polyester resin. 20 to 70% by weight based on the total solid content, acid value of 10 to 70 mgKOH / g, hydroxyl value of 70 to 170 mgKOH / g, and benzene ring concentration of 1.25 mol / kg (resin solid content) or less A polyester resin, wherein a carboxyl group in the resin is neutralized with a neutralizing agent, a curing agent which is a methyl ether / butyl ether mixed melamine or block polyisocyanate, a coloring pigment, and (a) a tertiary amino A polymerizable unsaturated molecule containing at least one ionic functional group selected from a group, a quaternary ammonium base and a sulfonic acid group 1 to 40% by weight of a monomer, (b) 5 to 40% by weight of a nonionic polymerizable unsaturated monomer having a polyoxyalkylene chain having a molecular weight of 200 to 3,000, and (c) the monomer (b) Contains an acrylic resin for pigment dispersion obtained by copolymerizing a monomer mixture comprising 20 to 94% by weight of another ethylenically unsaturated monomer containing a hydroxyl group-containing polymerizable unsaturated monomer other than the above in the presence of a radical polymerization initiator. An aqueous topcoat one-coat paint composition is disclosed. However, the water-based topcoat 1-coat coating composition may not be able to satisfy the coating film quality even if it is directly applied to a plastic material and baked and cured.

Patent Document 3 also discloses (A) at least one water-soluble or water-dispersible polyester, (B) at least one water-soluble or water-dispersible polyurethane acrylate, (C) itself or component (A). And (B) at least one aminoplast resin that is water-soluble or water-dispersible, and (D) at least one pigment and / or filler that imparts color and / or glitter, and optionally (E) In an aqueous coating material containing at least one polyisocyanate, the polyester (A) contains the following components: a1) a mixture containing the following components: a11) at least one aliphatic or cycloaliphatic poly Carboxylic acid or at least one esterifiable derivative of an aliphatic or cycloaliphatic polycarboxylic acid or a mixture of at least two of these starting products 40 80 mol%, a12) 20-60 mol% of at least one aromatic polycarboxylic acid, at least one esterifiable derivative of aromatic polycarboxylic acid or a mixture of at least two of these starting products; and a2) aliphatic having at least one structural parts -C (R1R2) _-CH 2 OH (in the formula, R1 and R2 1 to 20 carbon atoms in the molecule, cycloaliphatic or aromatic hydrocarbon Water-based coating material characterized in that it can be produced from at least 60 mol% of at least one aliphatic or cycloaliphatic polyol having a radical or a methylol group) or a mixture of at least two of these starting products Is disclosed. However, the aqueous coating material cannot be applied to a plastic material having a low heat-resistant temperature, such as ABS, and cannot be baked and cured.

  Patent Document 4 includes (A) an average of two or more blocked tertiary isocyanate groups blocked with a nitrogen atom-containing heterocyclic compound, an acid value of 3 to 100 mgKOH / g, and a weight average molecular weight. Resin having a hydroxyl value of 10 to 250 mgKOH / g and a weight average molecular weight of 1,000 to 200,000, a polyester resin and a urethane-modified polyester resin. It is possible to obtain sufficient curability even under relatively low-temperature baking conditions of 120 ° C. or lower, characterized in that it contains at least one hydroxyl group-containing resin selected from the above and (C) a curing catalyst as essential components. A waterborne coating composition is disclosed. However, the water-based paint composition is basically a base coat paint composition for two coats using a clear for the top coat, and the gloss appearance and chemical resistance may not be sufficient when one coat is applied.

JP 2010-69372 A Japanese Patent No. 4246953 Special table 2003-50483 Japanese Patent Laying-Open No. 2005-298591

  Therefore, the present invention applies a two-part aqueous one-coat paint composition capable of obtaining a coating film excellent in appearance, weather resistance, and chemical resistance, and the two-part aqueous one-coat paint composition. It aims at providing the coating film obtained by this.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that the above-mentioned problems can be solved by a specific two-component aqueous one-coat coating composition, and have completed the present invention. It was.

  That is, the present invention contains a water-based acrylic resin (A), a water-based polyester resin (B) and a self-emulsifying isocyanate curing agent (C), and the resin (A) has a hydroxyl value of 50 to 150 mgKOH / g, number average. The molecular weight is 1000 to 5000, and the resin (B) has an acid value of 20 to 50 mgKOH / g, a hydroxyl value of 50 to 150 mgKOH / g, a number average molecular weight of 1000 to 5000, and a solubility parameter of 8.5 to 9.7. And 10 to 40% by mass of the dimer acid component in all monomer components, and the content of the resin (A) and the resin (B) is the total resin of the resin (A) and the resin (B). The resin (A) is 60 to 95% by mass, the resin (B) is 5 to 40% by mass with respect to the solid content, and the total of hydroxyl groups contained in the resin (A) and the resin (B) Curing agent (C There ratio of isocyanate groups contained in, about two-aqueous one-coat coating composition, which is a isocyanate group / hydroxyl group = 0.7 to 1.5.

  The present invention also relates to a coated product obtained by applying a two-component aqueous one-coat paint.

  By coating the two-component aqueous one-coat paint composition of the present invention on a synthetic resin substrate or the like, a coating film excellent in appearance, weather resistance, and chemical resistance can be obtained.

  The two-component aqueous one-coat paint composition of the present invention contains an aqueous acrylic resin (A), an aqueous polyester resin (B), and a self-emulsifying isocyanate curing agent (C).

<< Aqueous acrylic resin (A) >>
The water-based acrylic resin (A) is a water-soluble or water-dispersible acrylic resin, and can be obtained by a known method using a radical polymerization reaction using a radical polymerizable monomer as a raw material component.

  Examples of radical polymerizable monomers include (meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, and (meth) acrylic. N-butyl acid, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, lauryl (meth) acrylate , Stearyl (meth) acrylate, allyl alcohol, 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, styrene, cyclohexyl (meth) acrylate, (Meth) acrylic acid 4-tert-butylcyclohexyl, (meth) a Rironitoriru and the like. These radically polymerizable monomers are used in combination of at least two kinds.

  The hydroxyl value of the water-based acrylic resin (A) is 50 to 150 mgKOH / g, and 60 to 145 mgKOH / g is preferable and 80 to 140 mgKOH / g is more preferable from the viewpoints of adhesion, weather resistance, chemical resistance and moisture resistance. . When the hydroxyl value is less than 50 mgKOH / g, the weather resistance, chemical resistance, and moisture resistance may decrease, and when it exceeds 150 mgKOH / g, the adhesion may decrease.

  The number average molecular weight of the water-based acrylic resin (A) is 1000 to 5000, and preferably 1200 to 4500, more preferably 2500 to 3500, from the viewpoint of the stability and appearance of the resin. When the number average molecular weight is less than 1000, the stability of the water-based acrylic resin may be lowered, and when it exceeds 5000, the appearance may be lowered. In addition, the value of the number average molecular weight described in this specification is a value obtained by gel permeation chromatography (GPC) using polystyrene as a standard substance.

  The acid value of the water-based acrylic resin (A) is not particularly limited, but is preferably 20 to 50 mgKOH / g, more preferably 22 to 47 mgKOH / g, and more preferably 25 to 45 mgKOH / g from the viewpoint of resin stability and moisture resistance. More preferred. When the acid value is less than 20 mgKOH / g, the stability of the resin may be lowered, and when the acid value exceeds 50 mgKOH / g, the moisture resistance may be lowered.

<< Water-based polyester resin (B) >>
The water-based polyester resin (B) is a water-soluble or water-dispersible polyester resin, and can be obtained by a known method using an esterification reaction using a polyhydric alcohol and a polybasic acid as raw material components.

  Examples of the polyhydric alcohol that is a raw material component of the water-based polyester resin (B) include glycols and trihydric or higher polyhydric alcohols. Examples of the glycol include ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, neopentyl glycol, hexylene glycol, 1,3-butanediol, 1,4- Butanediol, 1,5-pentanediol, 1,6-hexanediol, 2-butyl-2-ethyl-1,3-propanediol, methylpropanediol, cyclohexanedimethanol, 3,3-diethyl-1,5- Examples include pentanediol. Examples of the trihydric or higher polyhydric alcohol include glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, and dipentaerythritol. These polyhydric alcohols can be used alone or in combination of two or more.

  As the polybasic acid that is a raw material component of the water-based polyester resin (B), a polyvalent carboxylic acid is usually used, but a monovalent fatty acid or the like can be used in combination as necessary. As polyvalent carboxylic acids, for example, isophthalic acid, tetrahydroisophthalic acid, hexahydroterephthalic acid, adipic acid, sebacic acid, azelaic acid, fumaric acid, itaconic acid, or phthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, trimellit Commonly used polyvalent carboxylic acids for producing polyester resins such as acid, succinic acid, maleic acid, pyromellitic acid, and acid anhydrides thereof can be used. In addition, dimer acid which is a dimer of a fatty acid having 16 to 20 carbon atoms can be used. Examples of the dimer acid which is a dimer of a fatty acid having 16 to 20 carbon atoms include Halidimer 200 (manufactured by Harima Chemicals), Empor 1062 (manufactured by Henkel), and the like. These can be used alone or in combination of two or more.

  The dimer acid used for the water-based polyester resin (B) contains 10 to 40% by mass in all monomer components, and 12 to 38% by mass in all monomer components from the viewpoint of appearance and adhesiveness. Is preferable, and it is more preferable to contain 15-30 mass%. If the content of dimer acid is less than 10% by mass in the total monomer components, the appearance may decrease, and if it exceeds 40% by mass in the total monomer components, the tackiness may decrease. .

  The acid value of the water-based polyester resin (B) is 20 to 50 mgKOH / g, preferably 22 to 47 mgKOH / g, more preferably 25 to 45 mgKOH / g, from the viewpoint of the stability and moisture resistance of the resin. When the acid value is less than 20 mgKOH / g, the stability of the resin may be lowered, and when the acid value exceeds 50 mgKOH / g, the moisture resistance may be lowered.

  The hydroxyl value of the water-based polyester resin (B) is 50 to 150 mgKOH / g, and 60 to 145 mgKOH / g is preferable and 80 to 140 mgKOH / g is more preferable from the viewpoints of adhesion, weather resistance, chemical resistance and moisture resistance. . When the hydroxyl value is less than 50 mgKOH / g, the weather resistance, chemical resistance, and moisture resistance may decrease, and when it exceeds 150 mgKOH / g, the adhesion may decrease.

  The number average molecular weight of the water-based polyester resin (B) is 1000 to 5000, and preferably 1200 to 4800, more preferably 1500 to 4600, from the viewpoint of the stability and appearance of the resin. If the number average molecular weight is less than 1000, the stability of the resin may be lowered, and if it exceeds 5000, the appearance may be lowered.

  The water-based polyester resin (B) has a solubility parameter in the range of 8.5 to 9.7, and is preferably 8.7 to 9.6 from the viewpoint of appearance and storage stability. When the solubility parameter is less than 8.5, the storage stability may decrease, and when it exceeds 9.7, the appearance may decrease.

  The solubility parameter (SP) can be measured by the following method. 1 g of resin solid content was diluted 50 times with acetone, and n-hexane was added to this solution little by little, and the solubility parameter value (SPH) of the acetone / hexane mixed solvent at the time when the solution became cloudy, and 1 g of resin solid content were added to acetone. The solution can be determined as SP = (SPH + SPW) / 2 from the solubility parameter value (SPW) of the acetone / water mixed solution at the time when the solution becomes white turbid by adding distilled water little by little.

  The content of the water-based acrylic resin (A) and the water-based polyester resin (B) used in the two-component water-based one-coat paint composition of the present invention is the total resin solid content of the water-based acrylic resin (A) and the water-based polyester resin (B). On the other hand, the water-based acrylic resin (A) is 60 to 95% by mass, the water-based polyester resin (B) is 5 to 40% by mass, and the water-based acrylic resin (A) is 70 to 90% by mass from the viewpoint of adhesiveness and appearance. % Is more preferable. If the content of the water-based acrylic resin (A) is less than 60% by mass, the tackiness may be reduced, and if the content of the water-based polyester resin (B) is less than 5% by mass, the appearance may be decreased. .

<< Isocyanate curing agent (C) >>
The two-component aqueous one-coat paint composition of the present invention is a self-emulsifiable isocyanate curing agent (C) as a crosslinking agent that reacts with the functional group of the aqueous acrylic resin (A) and the functional group of the aqueous polyester resin (B). Containing. Examples of the isocyanate curing agent (C) include a polyisocyanate compound and a blocked polyisocyanate compound. Self-emulsification can be applied to a plastic material having a low heat resistance, for example, ABS, and can be baked and cured. Polyisocyanate compounds are preferred.

  A commercially available product can be used as the self-emulsifying polyisocyanate compound. Commercially available products include, for example, bihijoule 3100, bihijoule VPLS2319, bihijoule VPLS2336, bihijoule VPLS2150 / 1, bihijoule VPLS2150BA, bihijoule VPLS2306, bihijoule XP2451, bihijoule XP2487 / 1, bihijoule XP2547, NS -5500, Vernock DNW-6000, Vernock DNW-6500 (manufactured by DIC), Duranate WB40-100, Duranate WB40-80D, Duranate WT20-100, Duranate WT30-100, Duranate WE50-100, Duranate WL70-100, Duranate WL76 -100, Yuraneto WR80-70P (manufactured by Asahi Kasei Chemicals Co., Ltd.), Takenate WD-725, Takenate XWD-HS30, Takenate XWD-HS7 (manufactured by Mitsui Chemicals, Inc.), and the like. These compounds may be used individually by 1 type, or may be used in combination of 2 or more type.

  The ratio (molar ratio) of the hydroxyl groups contained in the aqueous acrylic resin (A) and the aqueous polyester resin (B) to the functional groups of the isocyanate groups contained in the isocyanate curing agent (C) is isocyanate group / hydroxyl group = 0.7. It is in the range of -1.5, and 0.8-1.45 are preferable and 1.0-1.3 are more preferable from the point of adhesiveness, chemical resistance, and moisture resistance. When the ratio of isocyanate group / hydroxyl group is less than 0.7, chemical resistance and moisture resistance may be lowered, and when it exceeds 1.5, adhesiveness and moisture resistance may be lowered.

<< Aluminum pigment >>
The two-component aqueous one-coat paint composition of the present invention can contain an aluminum pigment as a bright pigment. The aluminum pigment used in the two-component aqueous one-coat coating composition is preferably inactivated with respect to water with a compound containing a phosphoric acid group or a molybdic acid group, or a silica compound. Alpaste WX series (manufactured by Toyo Aluminum Co., Ltd.) can be used as an aluminum pigment that has been inactivated with respect to water with a compound containing a phosphate group. Examples of the aluminum pigment that has been inactivated with respect to water with a compound containing a molybdate group include Alpaste WL series (manufactured by Toyo Aluminum Co., Ltd.). Examples of aluminum pigments that have been deactivated with respect to water with silica compounds include Alpaste WZ series (manufactured by Toyo Aluminum Co., Ltd.), STAPA IL Hydrolan series (manufactured by ECKART Corp.), and the like. These aluminum pigments may be used individually by 1 type, or may be used in combination of 2 or more type.

  The range of the aluminum pigment that can be contained in the two-component aqueous one-coat paint composition of the present invention is based on the total resin solid content of the aqueous acrylic resin (A), the aqueous polyester resin (B), and the polyisocyanate compound (C). The mass ratio of the aluminum pigment is not particularly limited, but is preferably in the range of 6 to 15 mass%, more preferably 7 to 12 mass% from the viewpoint of concealment and appearance.

<< Other additives >>
In the two-component aqueous one-coat paint composition of the present invention, mica flake pigments, silica flake pigments, alumina flake pigments, glass flake pigments and the like may be used in combination with aluminum pigments as necessary.

  The two-component aqueous one-coat coating composition of the present invention can also contain a color pigment, if necessary. Examples of the color pigment include inorganic pigments such as chrome yellow, yellow iron oxide, iron oxide, carbon black, and titanium dioxide, azo chelate pigments, insoluble azo pigments, condensed azo pigments, phthalocyanine pigments, indigo pigments, and perinones. Organic pigments such as pigments, perylene pigments, dioxane pigments, quinacridone pigments, isoindolinone pigments, metal complex pigments. These color pigments may be used alone or in combination of two or more.

  The two-component aqueous one-coat paint composition of the present invention can contain an ultraviolet absorber. Examples of the ultraviolet absorber include benzotriazole-based and oxalic acid anilide-based ultraviolet absorbers. These ultraviolet absorbers may be used individually by 1 type, or may be used in combination of 2 or more type.

  When the ultraviolet absorber is included in the two-component aqueous one-coat paint composition of the present invention, the total resin solid content of the aqueous acrylic resin (A), the aqueous polyester resin (B), and the polyisocyanate compound (C), The mass ratio of the ultraviolet absorber is not particularly limited, but is preferably 0.5 to 5% by mass and more preferably 1 to 4% by mass from the viewpoint of weather resistance.

  The two-component aqueous one-coat paint composition of the present invention can contain a light stabilizer. Examples of the light stabilizer include hindered amine light stabilizers. These light stabilizers may be used individually by 1 type, or may be used in combination of 2 or more type.

  When the light stabilizer is contained in the aqueous one-coat coating composition of the present invention, the light stabilizer is based on the total resin solid content of the water-based acrylic resin (A), the water-based polyester resin (B), and the polyisocyanate compound (C). The mass ratio is not particularly limited, but is preferably 0.5 to 5% by mass and more preferably 1 to 4% by mass from the viewpoint of weather resistance.

  For example, extender pigments such as calcium carbonate, barite, precipitated barium sulfate, clay, and talc can be contained in the two-component aqueous one-coat paint composition of the present invention. Furthermore, the two-component aqueous one-coat coating composition of the present invention includes various additives such as a surface conditioner, an anti-settling agent, an antifoaming agent, a surfactant, a film-forming aid, an antiseptic, and an antioxidant. One or more kinds of various rheology control agents and various organic solvents can be contained.

<< Coating method and conditions >>
The two-component aqueous one-coat paint composition of the present invention is separated into a main ingredient containing an aqueous acrylic resin (A) and an aqueous polyester resin (B) and an isocyanate curing agent (C) during storage. Just before mixing and stirring these. At that time, if necessary, water, and in some cases, a small amount of an organic solvent or an amine is used to dilute to an appropriate viscosity before being used for coating.

  As a coating method of the two-component aqueous one-coat coating composition of the present invention, a method usually used in the automobile industry, for example, air atomization coating, bell rotation atomization coating, electrostatic or non-electrostatic coating, etc. is applied. it can.

  Examples of the object to be coated include a metal material having an electrodeposition coating film formed on the surface, a metal material having an intermediate coating film formed on the electrodeposition coating film, and a plastic material.

  Although the temperature and humidity conditions at the time of application | coating of the 2 liquid type 1-coat coating composition of this invention are not specifically limited, For example, they are 15-35 degreeC and 65-85% (relative humidity). Moreover, the dry film thickness of the coating film which apply | coated the water-system 1 coat coating composition is 10-40 micrometers, for example, From the point of concealment property and coating workability | operativity, it is preferably 15-30 micrometers.

  After the application of the two-component aqueous one-coat paint composition of the present invention, preliminary drying may be performed. In addition, as for the conditions in the case of performing preliminary drying, 60-80 degreeC and 3 to 10 minutes are preferable.

  The heat curing temperature and time after coating of the two-component aqueous one-coat coating composition of the present invention are preferably, for example, 80 to 120 ° C. and 10 to 60 minutes.

  The coated product obtained by applying the coating composition of the present invention is excellent in properties such as gloss and chemical resistance, and it is not necessary to apply a clear coating thereon. Therefore, the step of painting the clear paint can be omitted, and the painting cost can be reduced.

  Hereinafter, although an example is given and the present invention is explained still in detail, the present invention is not limited to this. In addition, unless otherwise indicated, the part,%, and ratio in each example represent a mass part, mass%, and mass ratio, respectively.

<Production Example 1: Production of water-based acrylic resin A1>
A four-necked flask equipped with a reflux condenser, a thermometer, a stirrer, and a dropping funnel was charged with 39.4 parts of solvent naphtha and 59.1 parts of butyl glycol described in I of Table 1 and heated to 145 ° C. . Next, 4.3 parts of glycidyl methacrylate described in II of Table 1, 22.5 parts of 2-hydroxyethyl methacrylate, 30.0 parts of styrene, 68.1 parts of n-butyl acrylate, 150.0 parts of methyl methacrylate, A mixture of 25.1 parts of n-butyl methacrylate and 9.6 of di-t-butyl peroxide was added dropwise over 3 hours. 30 minutes after the completion of dropping, 29.2 parts of 2-hydroxyethyl methacrylate, 27.8 parts of n-butyl acrylate, 28.0 parts of methyl methacrylate, 15.0 parts of acrylic acid and 15.0 parts of acrylic acid described in III of Table 1 A mixture of 5.6 parts of di-t-butyl peroxide was added dropwise over 2 hours. 30 minutes after the completion of the dropwise addition, a mixture of 1.6 parts of di-t-butyl peroxide described in IV of Table 1 and 14.4 parts of solvent naphtha was dropped over 30 minutes. The mixture was further stirred at 145 ° C. for 2 hours and then cooled to 98 ° C. 16.7 parts of dimethylethanolamine described in V of Table 1 was added and stirring was continued for 30 minutes, and then the reaction product was dispersed in 453.7 parts of deionized water described in VI of Table 1 to obtain an aqueous acrylic resin. A1 was obtained. The characteristic value of the acrylic resin varnish was 40.4% by mass of the heating residue, the hydroxyl value of the resin was 60 mgKOH / g, and the molecular weight in terms of polystyrene by GPC was 2700.

<Production Examples 2 to 9: Production of water-based acrylic resins A2 to A9>
Based on the formulation shown in Table 1, aqueous acrylic resins A2 to A9 were obtained in the same manner as in Production Example 1. The characteristic values of the obtained water-based acrylic resin and the evaluation results of varnish stability are shown in Table 1.

The stability of the water-based acrylic resin was evaluated according to the following criteria by leaving the water-based acrylic resin in a constant temperature bath at 40 ° C.
X: Sedimentation is observed after one month.
○: No sedimentation is observed after 1 month, but sedimentation is observed after 2 months.
A: No sedimentation is observed even after 2 months.

<Production Example 10: Production of water-based polyester resin B1>
In a four-necked flask equipped with a reflux condenser, a thermometer, a stirrer, and a dropping funnel, 120 parts of dimer acid (Haridimer 200 manufactured by Harima Chemical Co., Ltd.) described in I of Table 2, 150 parts of hexahydrophthalic anhydride, 2- 150 parts of ethyl-2-butyl-1,3-propanediol, 52.3 parts of 1,6-hexanediol and 59.5 parts of trimethylolpropane were charged, heated to 150 ° C. and uniformly dissolved. Thereafter, the temperature was raised to 150 ° C. to 230 ° C. over 5 hours, and while holding 30 parts of xylene, the water generated by the esterification reaction was fractionated and held at 230 ° C. for 2 hours, resulting in a resin acid value of 10-11. After confirming this, it was cooled to 140 ° C., and xylene was distilled off under reduced pressure. After charging 68.2 parts of trimellitic anhydride described in II of Table 2 at 140 ° C., holding at 160 ° C. for 30 minutes, raising the temperature to 185 ° C., and confirming that the resin acid value was 29 to 31, 150 Cooled to ° C. At 150 ° C., 190 parts of butyl glycol described in III of Table 2 was added, stirred for 15 minutes or more to make the contents uniform, and then cooled to 65 ° C. Charge 22.9 parts of dimethylethanolamine described in IV of Table 2 at 65 ° C., stir for 30 minutes, stop stirring once, charge 218.7 parts of deionized water described in V of Table 2 and stir for 30 minutes or more did. Water-based polyester resin B1 was obtained. The characteristic values of the water-based polyester resin are 59.1% by mass of the heating residue, the resin acid value of 35 mgKOH / g, the resin hydroxyl value of 100 mgKOH / g, the polystyrene equivalent molecular weight by GPC is the number average molecular weight 2000, the solubility parameter 9.1 (actual value) )Met.

<Production Examples 11 to 28: Production of water-based polyester resins B2 to B19>
Based on the formulation shown in Table 2, aqueous polyester resins B2 to B19 were obtained in the same manner as in Production Example 10. Table 2 shows the characteristic values of the obtained water-based polyester resin. The characteristic values of the obtained water-based polyester resin and the evaluation results of varnish stability are shown in Table 2.

In addition, about stability of water-system polyester resin, water-system polyester resin was left to stand in a 40 degreeC thermostat, and the following references | standards evaluated.
X: Sedimentation is observed after one month.
○: No sedimentation is observed after 1 month, but sedimentation is observed after 2 months.
A: No sedimentation is observed even after 2 months.

Example 1
According to the formulation shown in Table 3, as described in I, 42.7 parts of acrylic resin A2 obtained in Production Example 2 and 16 parts of deionized water were charged and stirred uniformly. Furthermore, as described in II, 7.2 parts of the polyester resin B1 obtained in Production Example 10, 2 parts of butyl glycol, 0.6 part of an ultraviolet absorber (Tinuvin384-2 manufactured by BASF Japan), light stabilization 0.6 parts of the agent (BASF Japan Tinuvin292) was mixed uniformly in a separate container, and 4.5 parts of aluminum pigment (STAPA IL Hydrolan2192 made by ECKART) was added, and the pigment dispersed with a dissolver was added. . Thereafter, as described in III, 0.35 parts of dimethylaminoethanol, 11.2 parts of deionized water, 2 parts of a thickener (ViscalexHV30 manufactured by BASF Japan) under stirring, an anti-settling agent (manufactured by Enomoto Kasei Co., Ltd.) A main agent was prepared by adding 1 part of Disparon AQH800) and 0.5 part of a surface conditioner (BYK-346 manufactured by BYK Chemie). Next, as described in IV, 11.3 parts of an isocyanate curing agent (Bayhydrol XP2655 manufactured by Sumika Bayer Urethane Co., Ltd.) adjusted to 80% resin solid content with propylene glycol monomethyl ether acetate under stirring is added and dispersed uniformly. The mixture was mixed to make a water-based paint. The solid content of the water-based paint was 30.3%. The above-mentioned paint was air spray coated on an isopropyl alcohol degreased and washed ABS plate to a dry film thickness of 30 μm, and baked at 80 ° C. for 30 minutes for drying. The coating performance test results are shown in Table 3.

In addition, the performance of the coating film obtained by the coating composition of this invention was evaluated as follows.
(1) Adhesiveness of coating film The test plate was evaluated by the number of squares of a grid obtained by cutting 100 square grids with a 1 × 1 mm square using a cutter knife and peeling with cellophane tape.
○: The number of squares of the peeled grid is 0: The number of squares of the peeled square is 1 to 5 ×: The number of squares of the peeled grid exceeds 5

(2) Gloss Value The test plate was evaluated by measuring a 60-degree gloss value according to JIS K 5400 7.6 using a gloss meter (BYK Chemie, Micro TRI-GLOSS).
：: 60 degree gloss value of 90 or more ○: 60 degree gloss value of 80 or more Δ: 60 degree gloss value of 70 to 79
X: 60 degree gloss value is less than 70

(3) Accelerated weather resistance Using a sunshine carbon arc lamp type weather resistance tester (JIS B7753), the test plate was 1000 hours under the conditions of a black panel temperature of 70 ± 3 ° C. and a rainfall time of 12 minutes (60 minutes irradiation). The 60 degree gloss retention after the test was evaluated.
○: 60 degree gloss retention is 80% or more x: 60 degree gloss retention is less than 80%

(4) Chemical resistance With respect to the test plate, 2 mL of a sodium hydroxide solution having a normality of 0.1 concentration was spotted in a circular shape with a diameter of 2 cm, and heated at 55 ° C. for 4 hours, taking care not to evaporate the chemical solution. Immediately after the heating, the spot portion was washed with tap water, and the coating film after drying was evaluated by the color difference between the spot portion and the outside of the spot. For color difference, ΔE was measured using a color difference meter (Konica Minolta, CR-400).
◎: ΔE is less than 1.5 ○: ΔE is 1.5 or more and less than 3 ×: ΔE is 3 or more

(5) Adhesiveness About the test plate, five sheets of gauze were placed on the coating surface, a 500 g weight with a diameter of 4 cm was placed on the gauze, and heated at 70 ° C. for 2 hours to evaluate the tackiness.
◎: No tackiness, no gauze trace ○: No tackiness, but slight gauze trace △: No tackiness, clear gauze trace ×: Sticky

(6) Moisture resistance The test plate was left in a blister box at 50 ° C. and a relative humidity of 95% for 240 hours, and the coating surface after the test was evaluated.
○: No swelling △: Does not swell but glossy x: Swells

(7) Storage stability The main agent was allowed to stand at 20 ° C and evaluated according to the following criteria.
◎: No abnormality for 1 month or more ○: Sedimentation separation of pigment and resin is observed in 0.5 to 1 month Δ: Sedimentation separation of pigment and resin is recognized in 1 week to 0.5 month × Within 1 week Sedimentation separation of pigment and resin is observed

(Examples 2 to 17)
In accordance with the formulation shown in Table 3, a paint was prepared by the same method as in Example 1, painted and baked, and in accordance with Example 1, a coating performance test of the coated product was performed. The coating performance test results are shown in Table 3.

(Comparative Examples 1-18)
In accordance with the formulation shown in Table 4, a paint was prepared in the same manner as in Example 1, painted and baked, and in accordance with Example 1, a coating performance test of the coated product was performed. Table 4 shows the coating performance test results.

<Discussion>
In Examples 1 to 17, excellent results were obtained in all of the seven evaluation items listed in Tables 3 to 4.

On the other hand, in Comparative Examples 1-18, it was set to x or (triangle | delta) in at least 1 of the seven evaluation items listed in Tables 3-4, and the evaluation result was inferior to the Example. Specifically, it is as follows.
In Comparative Example 1 having a solubility parameter of less than 8.5, the storage stability was poor. In Comparative Example 2 in which the solubility parameter exceeds 9.7, the gloss value was inferior.
In Comparative Example 3 in which the dimer acid component in the monomer of the resin (B) was less than 10% by mass, the gloss value was inferior. In Comparative Example 4 in which the dimer acid component in the monomer of the resin (B) exceeds 40% by mass, the adhesiveness was inferior.
In Comparative Example 5 in which the ratio of the resin (A) exceeds 90% by mass, the gloss value was inferior. In Comparative Example 6 in which the ratio of the resin (A) was less than 60% by mass, the adhesiveness was inferior.
In Comparative Example 7 in which the value of isocyanate group / hydroxyl group was less than 0.7, chemical resistance and moisture resistance were inferior. In Comparative Example 8 in which the value of isocyanate group / hydroxyl group exceeded 1.5, the tackiness and moisture resistance were inferior.
In Comparative Example 9 in which the hydroxyl value of the resin (A) was less than 50 mgKOH / g, the accelerated weather resistance, chemical resistance, and moisture resistance were inferior. In Comparative Example 10 in which the hydroxyl value of the resin (A) exceeds 150 mgKOH / g, the coating film adhesion was inferior.
In Comparative Example 11 in which the number average molecular weight of the resin (A) is less than 1000, the storage stability was inferior. In Comparative Example 12 in which the number average molecular weight of the resin (A) exceeds 5000, the gloss value is inferior.
In Comparative Example 13 where the acid value of the resin (B) is less than 20 mgKOH / g, the storage stability was inferior. In Comparative Example 14 in which the oxidation of the resin (B) exceeded 50 mgKOH / g, the moisture resistance was inferior.
In Comparative Example 15 in which the hydroxyl value of the resin (B) was less than 50 mgKOH / g, the accelerated weather resistance, chemical resistance, and moisture resistance were inferior. In Comparative Example 16 in which the hydroxyl value of the resin (B) exceeded 150 mgKOH / g, the coating film adhesion was inferior.
In Comparative Example 17 in which the number average molecular weight of the resin (B) is less than 1000, the storage stability was inferior. In Comparative Example 18 in which the number average molecular weight of the resin (B) exceeds 5000, the gloss value is inferior.

  From these results, in order to obtain excellent results in all of the seven evaluation items required for the two-component aqueous one-coat paint composition, the resin (A) and the resin (B) have specific characteristics, In addition, it is essential that the ratio of the resin (A) to the resin (B) and the ratio of the isocyanate group to the hydroxyl group be within a specific range. If any one of these requirements is out of the specified range, the ratio is excellent. It turned out that an evaluation result is not obtained.

Claims (2)

Contains an aqueous acrylic resin (A), an aqueous polyester resin (B) and a self-emulsifying isocyanate curing agent (C),
The resin (A) has a hydroxyl value of 50 to 150 mgKOH / g and a number average molecular weight of 1000 to 5000,
The resin (B) has an acid value of 20 to 50 mgKOH / g, a hydroxyl value of 50 to 150 mgKOH / g, a number average molecular weight of 1000 to 5000, a solubility parameter of 8.5 to 9.7, and a total dimer acid component. 10 to 40% by mass in the monomer component,
Content of the said resin (A) and the said resin (B) is 60-95 mass% of said resin (A) with respect to the total resin solid of said resin (A) and said resin (B), and said resin (B ) Is 5-40% by mass,
The ratio of isocyanate groups contained in the total of hydroxyl groups contained in the resin (A) and the resin (B) and the curing agent (C) is isocyanate group / hydroxyl group = 0.7 to 1.5. A two-component aqueous one-coat paint composition. A coated product obtained by applying the two-component water-based one-coat paint according to claim 1.