JP5947769B2 - Two-component water-based paint composition - Google Patents

Description

  The present invention relates to a two-component water-based paint composition having excellent pot life.

  VOCs (volatile organic compounds) are considered to be a cause of air pollution, and suppression of emission is required. As one of the measures for suppressing VOC emission, switching from a solvent-based paint to a water-based paint is performed. As the two-component water-based paint, for example, a paint in which a polyol resin having a hydroxyl group as a main agent and an isocyanate resin having an isocyanate group as a curing agent is mixed is known (see, for example, Patent Document 1).

JP 2007-284480 A

  The isocyanate group has a high reactivity with water molecules. For this reason, in the water-based paint, the isocyanate resin does not sufficiently react with the polyol resin, and sufficient film properties may not be obtained. Further, the reaction between the isocyanate resin and water tends to increase the viscosity of the paint and shorten the pot life.

  An object of the present invention is to provide a two-component water-based paint composition having a coating film property equivalent to that of a solvent-based paint and excellent in pot life.

The two-component water-based coating composition according to the present invention contains a main resin, an acrylic polyol resin as a dispersoid, a first liquid containing alcohol as an auxiliary agent and water as a dispersion medium, and a polyisocyanate resin as a curing agent. A secondary alcohol having an octanol / water partition coefficient of less than 3.00, a secondary alcohol having an octanol / water partition coefficient of less than 3.47, or It is at least one of tertiary alcohols, the acid value of the acrylic polyol resin is 10 to 25 mg KOH / g, and the molar equivalent of the isocyanate group that the polyisocyanate resin has relative to the molar equivalent 1 of the hydroxyl group that the acrylic polyol resin has characterized but is 1.5 to 3, to advance the curing reaction by mixing the second liquid with the first liquid To.

  In the two-component water-based paint composition according to the present invention, the alcohol preferably has a boiling point of 170 ° C. or lower.

  In the two-component water-based paint composition according to the present invention, the acrylic polyol resin is preferably a colloidal dispersion type. Storage stability can be further extended. Moreover, the smoothness of the coating film obtained can be improved more.

  In the two-component water-based paint composition according to the present invention, the colloidal dispersion type acrylic polyol resin is a resin dispersed in water by imparting hydrophilicity to the polymer particles themselves without using an emulsifier. Is included.

  In the two-component water-based paint composition according to the present invention, the tertiary alcohol preferably has an octanol / water partition coefficient of 0.4 or less.

  In the two-component water-based paint composition according to the present invention, the alcohol is an auxiliary agent for assisting the dispersibility of the polyisocyanate resin in water, and an assistant for extending the pot life of the two-component water-based paint composition. It preferably acts as at least one of an agent or an auxiliary agent for adjusting the viscosity of the first liquid.

  The present invention can provide a two-component water-based paint composition having a coating film property equivalent to that of a solvent-based paint and excellent pot life.

  The embodiments described below are examples of the present invention, and the present invention is not limited to the following embodiments. Various modifications may be made as long as the effects of the present invention are achieved.

  The two-component water-based paint composition according to this embodiment comprises a main resin and an acrylic polyol resin as a dispersoid, a first liquid containing alcohol as an auxiliary agent and water as a dispersion medium, and a polyisocyanate resin as a curing agent A second alcohol containing, a primary alcohol having an octanol / water partition coefficient of less than 3.00, a secondary alcohol having an octanol / water partition coefficient of less than 3.47, or It is at least one of tertiary alcohols, and the first liquid and the second liquid are mixed to advance the curing reaction.

  The first liquid contains an acrylic polyol resin as a main resin, alcohol as an auxiliary agent, and water as a dispersion medium.

  The acrylic polyol resin as the main resin is an acrylic resin having a hydroxyl group in the molecule. The acrylic polyol resin is, for example, a copolymer of a hydroxyl group-containing acrylic monomer and another acrylic or non-acrylic vinyl monomer. Moreover, the polymer of a hydroxyl-containing acrylic monomer is included. Hydroxyl group-containing acrylic monomers include, for example, monomers having a hydroxyl group such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, and 4-hydroxybutyl methacrylate. A ring-opening adduct of γ-butyrolactone to 2-hydroxyethyl methacrylate, and a ring-opening adduct of ε-caprolactone to 2-hydroxyethyl acrylate.

  Other acrylic or non-acrylic vinyl monomers include, for example, methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, n-amyl acrylate, isoamyl acrylate, n-hexyl acrylate Acrylic esters such as 2-ethylhexyl acrylate, n-octyl acrylate, decyl acrylate, dodecyl acrylate, cyclohexyl acrylate, isobornyl acrylate, stearyl acrylate, methyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl Methacrylate, n-amyl methacrylate, n-hexyl methacrylate, n-octyl meta Relate, 2-ethylhexyl methacrylate, decyl methacrylate, dodecyl methacrylate, cyclohexyl methacrylate, isobornyl methacrylate, methacrylic acid ester such as stearyl methacrylate, carboxyl group-containing monomers such as acrylic acid, methacrylic acid, styrene, α-methylstyrene, vinyltoluene Styrene derivatives such as paramethylstyrene and chlorostyrene, vinyl esters such as vinyl acetate and vinyl propionate, vinyl halide monomers such as vinyl chloride and vinylidene chloride, acrylamide, diacetone acrylamide, N-methylol acrylamide, acrylonitrile, methacrylamide And nitrogen-containing vinyl monomers such as methacrylonitrile. Any of these may be used alone or in appropriate combination of two or more. This embodiment is not limited to the type of monomer and polymerization method.

  The acrylic polyol resin is preferably a colloidal dispersion type. By using a colloidal dispersion type, the storage stability can be further extended. Moreover, the smoothness of the coating film obtained can be improved more. In the present specification, the colloidal dispersion type refers to those in which an emulsifier is not used, hydrophilicity is imparted to the polymer particles themselves, dispersed in water, and in an intermediate state between an aqueous solution and an emulsion. . Its appearance is translucent to milky white. In the colloidal dispersion type acrylic polyol resin, the average particle size is preferably 10 nm or more and 200 nm or less. More preferably, it is 50 nm or more and 170 nm or less, and particularly preferably 100 nm or more and 160 nm or less. If the average particle size is less than 10 nm, the water resistance of the resulting coating film may be inferior. When it exceeds 200 nm, storage stability may be inferior. Moreover, the smoothness of the coating film obtained may be inferior. In this specification, the average particle diameter means a median diameter measured by a laser diffraction method. In the colloidal dispersion type acrylic polyol resin, the number average molecular weight (Mn) is preferably 1,000 to 1,000,000, and more preferably 2,000 to 50,000.

The number average molecular weight (Mn) of the acrylic polyol resin is preferably 1,000 to 1,000,000, more preferably 2,000 to 50,000, and 2,000 to 30,000. It is particularly preferred. When the Mn of the acrylic polyol resin is less than 1,000, the coating film strength may be insufficient. If it exceeds 1,000,000, the viscosity of the paint becomes too high, and a uniform coating film may not be formed. In this specification, the number average molecular weight is a numerical value obtained from Equation 1.
(Expression 1) Mn = (56100 / OHV) · fn
In Equation 1, OHV is a hydroxyl value determined according to JIS K 1557-1: 2007 “Plastics—Polyurethane raw material polyol test method—Part 1: Determination of hydroxyl value”. Fn is the average number of functional groups per molecule.

  The hydroxyl value (OHV) of the acrylic polyol resin is preferably 20 to 200 mgKOH / g, and more preferably 20 to 150 mgKOH / g. When the acrylic polyol resin has an OHV of less than 20 mgKOH / g, the crosslinking reaction point is small, and thus the crosslinking density becomes small and sufficient coating strength may not be obtained. As a result, the adhesion to the substrate tends to decrease, and the influence is particularly remarkable under high humidity conditions. When it exceeds 200 mgKOH / g, the curing shrinkage due to the crosslinking reaction is large, and the adhesion to the substrate may be inferior. In the present specification, the hydroxyl value (OHV) is a numerical value obtained according to JIS K 1557-1: 2007.

  The acid value of the acrylic polyol resin is preferably 10 to 35 mgKOH / g, and more preferably 15 to 25 mgKOH / g. When the acid value of the acrylic polyol resin is less than 10 mgKOH / g, the dispersibility in water may be inferior. When the acid value of acrylic polyol resin exceeds 35 mgKOH / g, the water resistance and durability of the obtained coating film may be inferior.

  The glass transition point (Tg) of the acrylic polyol resin is preferably 20 to 100 ° C, and more preferably 50 to 80 ° C. The lower the Tg of the acrylic polyol resin, the lower the minimum film forming temperature (MFT, Minimum Film Forming Temperature). Therefore, the drying temperature tends to have a good film forming property at a low temperature. However, if the Tg of the acrylic polyol resin is less than 20 ° C., the resulting coating film may have insufficient water resistance. On the other hand, if Tg exceeds 100 ° C., MFT increases, and unless the drying temperature is increased, the crosslinking reaction does not proceed sufficiently and the strength of the resulting coating film may be insufficient. Further, when the drying temperature is increased, the running cost may increase or the base material may be deformed.

  Alcohol as an auxiliary agent assists the dispersibility of the polyisocyanate resin in water, and as a result, stabilizes the dispersion state of the polyisocyanate resin in water. In addition, the alcohol may act as an auxiliary agent for extending the pot life of the two-component aqueous coating composition and / or an auxiliary agent for adjusting the viscosity of the first liquid. Alcohol includes primary alcohol, secondary alcohol, and tertiary alcohol. The primary alcohol is, for example, methyl alcohol, ethyl alcohol, n-propyl alcohol, n-butyl alcohol, or isobutyl alcohol. The secondary alcohol is, for example, isopropyl alcohol. The tertiary alcohol is, for example, tert-butyl alcohol or diacetone alcohol (DAA). Moreover, you may contain the solvent which has a 2 or more functional group containing a hydroxyl group as an adjuvant. Examples of the solvent having two or more functional groups containing a hydroxyl group include ether alcohols having an ether group such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether; ethylene glycol, diethylene glycol, And glycols having two hydroxyl groups such as propylene glycol.

  When the alcohol is a primary alcohol, the octanol / water partition coefficient (hereinafter referred to as logPow) is preferably less than 3.00, and more preferably 1.00 or less. When the log Pow of the primary alcohol is 3.00 or more, the pot life property may be inferior. When the alcohol is a secondary alcohol, logPow is preferably less than 3.47, and more preferably 1.00 or less. If the log Pow of the primary alcohol is 3.47 or more, the pot life property may be inferior. When the alcohol is a tertiary alcohol, it can be a coating composition having excellent pot life regardless of logPow, but is preferably 0.40 or less, particularly preferably 0.10 or less. preferable.

  The boiling point of the alcohol is preferably 170 ° C. or lower, and more preferably 166 ° C. or lower. If the boiling point of the alcohol exceeds 170 ° C., the resulting coating film may have poor water resistance.

  The content of the alcohol is preferably 5 to 60 parts by mass and more preferably 10 to 50 parts by mass with respect to 100 parts by mass of the acrylic polyol resin. If it is less than 5 mass parts, the effect which assists the dispersibility to water of polyisocyanate resin may be scarce. Moreover, the effect which assists the film formability of resin is scarce, film-forming does not fully advance, and the intensity | strength of the coating film obtained may be insufficient. If it exceeds 60 parts by mass, it is difficult to say that VOC is suppressed.

  The content of water as a dispersion medium is preferably 50 to 300 parts by mass and more preferably 70 to 250 parts by mass with respect to 100 parts by mass of the acrylic polyol resin. If it is less than 50 parts by mass, the viscosity may be high and a uniform coating film may not be formed. When the amount exceeds 300 parts by mass, the coating film cannot be formed efficiently because the solid concentration is low.

  The first liquid may contain various additives in addition to the acrylic polyol resin as the main resin, the alcohol as the auxiliary agent, and the water as the dispersion medium. The various additives are, for example, a catalyst for accelerating the curing reaction, a surface conditioner, a lubricant, an antifoaming agent, a thickener, and a film forming aid. Among these, it is preferable that it is 5 mass parts or less with respect to 100 mass parts of acrylic polyol resin, and, as for content of a catalyst, it is more preferable that it is 1 mass part or less. If it exceeds 5 parts by mass, the reaction between the isocyanate resin and water may be promoted, and as a result, the adhesion of the coating film to the substrate may be inferior. Further, the total content of the various additives is preferably 20 parts by mass or less, and more preferably 5 parts by mass or less with respect to 100 parts by mass of the acrylic polyol resin.

  The second liquid contains a polyisocyanate resin as a curing agent.

  The polyisocyanate resin as a curing agent includes a hydrophobic polyisocyanate resin and a hydrophilic polyisocyanate resin. The hydrophobic polyisocyanate resin is an isocyanate resin that does not have a hydrophilic group in the molecule, and those commonly used in solvent-based paints can be used. By containing the hydrophobic polyisocyanate resin, a highly water-resistant coating film can be obtained. On the other hand, the hydrophilic polyisocyanate resin is a compound having a hydrophilic group and an isocyanate resin in which an isocyanate group is modified. Since the hydrophilic polyisocyanate resin has a hydrophilic group introduced therein, the water dispersibility and the compatibility with the polyol resin are better than those of the hydrophobic polyisocyanate resin. For this reason, the coating film of high appearance can be obtained by containing hydrophilic polyisocyanate resin. As the polyisocyanate resin, only a hydrophobic polyisocyanate resin may be used, or only a hydrophilic polyisocyanate resin may be used, or a hydrophobic polyisocyanate resin and a hydrophilic polyisocyanate resin may be used in combination.

  Examples of hydrophilic polyisocyanate resins include ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), dodecamethylene diisocyanate, 1,6,11-undecane triisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, and lysine diisocyanate. 2,6-diisocyanatomethylcaproate, bis (2-isocyanatoethyl) fumarate, bis (2-isocyanatoethyl) carbonate, 2-isocyanatoethyl-2,6-diisocyanatohexanoate, etc. Aliphatic polyisocyanate compounds; isophorone diisocyanate (IPDI), dicyclohexylmethane-4,4'-diisocyanate (hydrogenated MDI), cyclohexylene diisocyanate, methyl Cycloxylene diisocyanate (hydrogenated TDI), bis (2-isocyanatoethyl) -4-cyclohexene-1,2-dicarboxylate, 2,5-norbornane diisocyanate, 2,6-norbornane diisocyanate, etc. Isocyanate compounds; aromatic aliphatic polyisocyanate compounds such as m-xylylene diisocyanate (XDI), p-xylylene diisocyanate (XDI), α, α, α ′, α′-tetramethylxylylene diisocyanate (TMXDI); 3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 2,4-tolylene diisocyanate (TDI), 2,6-tolylene diisocyanate (TDI), crude TDI, 2,4′biphenylmethane diisocyanate (MDI), 4, 4 ' -Biphenylmethane diisocyanate (MDI), 4,4'-diisocyanatobiphenyl, 3,3'-dimethyl-4,4'-diisocyanatobiphenyl, 3,3'-dimethyl-4,4'-diisocyanato Aromatic polyisocyanate compounds such as diphenylmethane, crude MDI, 1,5-naphthylene diisocyanate, 4,4 ′, 4 ″ -triphenylmethane triisocyanate, m-isocyanatophenylsulfonyl isocyanate, p-isocyanatophenylsulfonyl isocyanate; Modification of polyisocyanates such as urethane-modified MDI, carbodiimide-modified MDI, trihydrocarbyl phosphate-modified MDI, urethane-modified TDI, biuret-modified HDI, isocyanurate-modified HDI, isocyanurate-modified IPDI It is a property. These may be used alone or in combination of two or more. The two types of combinations are, for example, a combination of modified MDI and urethane-modified TDI (isocyanate group-containing prepolymer).

  Commercially available products of hydrophilic polyisocyanate compounds include AQUANATE 100, AQUANATE 110, AQUANATE 200 and AQUANATE 210 (all trade names, manufactured by Nippon Polyurethane Industry Co., Ltd.); VPLS-2319, Bihydule 3100, VPLS-2336 and VPLS-2150 / 1 (all trade names, manufactured by Sumika Bayer Urethane Co., Ltd.); Takenate WD-720, Takenate WD-725, Takenate WD-220 (all trade names, Mitsui Takeda Chemical Co., Ltd.); Rezamin D-56 (trade name, manufactured by Dainichi Seika Kogyo Co., Ltd.) and the like may be used. These may be used alone or in combination of two or more.

  As the hydrophobic polyisocyanate compound, those usually used in a solvent system are preferable. For example, Desmodur N3400, Desmodur N3600, Desmodur VPLS2294 (all trade names, manufactured by Sumika Bayer Urethane Co., Ltd.), Takenate D-170HN ( Trade name, manufactured by Mitsui Takeda Chemical Co., Ltd.). These may be used alone or in combination of two or more.

  The content of the polyisocyanate resin is preferably such that the ratio of the molar equivalent of the isocyanate group (—NCO) to the molar equivalent 1 of the hydroxyl group (—OH) contained in the first liquid is 1.2 to 3. More preferably, it is 1.5-2. Here, the molar equivalent of the hydroxyl group contained in the first liquid is the molar equivalent of the hydroxyl group that the acrylic polyol resin has, and does not include the molar equivalent of the hydroxyl group that the alcohol has. If the ratio of the molar equivalent of the isocyanate group to the molar equivalent 1 of the hydroxyl group is less than 1.2, the strength of the resulting coating film may be insufficient. If it exceeds 3, adhesion to the substrate may be insufficient.

  The two-component water-based paint composition according to the present embodiment mixes the first liquid and the second liquid and applies them to the base material to advance the curing reaction.

  The base material is, for example, various plastics. Examples of the plastic include polycarbonate (PC), acrylonitrile butadiene styrene copolymer (ABS), polyacetal (POM), polyamide (PA), polyphenylene ether (PPE), polybutylene terephthalate (PBT), and polymethyl methacrylate (PMMA). Polypropylene (PP). The present invention is not limited to the type of substrate.

  The application method is not particularly limited, and examples thereof include dip coating, brush coating, roll brush coating, spray coating, roll coating, spin coating, dip coating, bar coating, flow coating, electrostatic coating, and die coating.

  The curing method may be either a method of heating the painted surface to advance the curing reaction, a method of allowing the coating surface to stand at room temperature to advance the curing reaction, or a method combining these methods. The present invention is not limited to the method for curing the coating film.

  The thickness of the coating film is not particularly limited as long as it is appropriately set depending on the application, but is preferably 15 to 50 μm, for example, and preferably 20 to 30 μm.

  EXAMPLES Hereinafter, although this invention is demonstrated further in detail based on an Example, this invention is not limited to this Example at all.

Example 1
Colloidal dispersion type acrylic polyol resin (Bernock WD-551, manufactured by DIC, acid value 19 mg KOH / g) 100 parts by mass, pure water 39.2 parts by mass, diacetone alcohol (octanol / water partition coefficient (hereinafter, logPow)): −0.41, boiling point: 166 ° C.) 6.8 parts by mass and thickener (Adecanol UH-541VF, manufactured by Adeka) 2.0 parts by mass with sufficient stirring and mixing. A liquid was obtained. To this first liquid, 28.0 parts by mass of a hydrophilized polyisocyanate resin (Bayhydr 3100, manufactured by Bayer) was added as a second liquid, and the mixture was stirred and mixed using a disper to obtain a coating composition.

(Example 2)
In Example 1, 6.8 parts by mass of diacetone alcohol was changed to 6.8 parts by mass of t-butyl alcohol (logPow: 0.40, boiling point: 82.4 ° C.). Thus, a coating composition was obtained.

(Comparative Example 1)
A coating composition was obtained in the same manner as in Example 1 except that 6.8 parts by mass of diacetone alcohol was changed to 6.8 parts by mass of pure water.

(Comparative Example 2)
In Example 1, 6.8 parts by mass of diacetone alcohol was changed to 6.8 parts by mass of texanol (logPow: 3.47, boiling point: 255 to 260 ° C.). I got a thing.

  The following evaluation was performed about the obtained coating composition of the Example or the comparative example.

(Viscosity change rate and pot life evaluation)
Immediately after mixing the first liquid and the second liquid, the viscometer (TVB-10M, manufactured by Toki Sangyo Co., Ltd.) is used to determine the viscosity of the coating composition after 1 hour, 3 hours and 5 hours. It was measured. The ratio of the viscosity of the coating composition after 1 hour, 3 hours and 5 hours to the viscosity of the coating composition immediately after mixing was defined as the viscosity change rate. The evaluation criteria for pot life is a practical level (○) when the viscosity change rate after 1 hour, 3 hours and 5 hours is 300% or less, 1 hour, 3 hours and 5 hours. A case where at least one of the subsequent viscosity change rates exceeds 300% was regarded as an unusable level (x). The evaluation results are shown in Table 1.

(Coating performance evaluation)
About the coating composition of an Example or a comparative example, immediately after mixing a 1st liquid and a 2nd liquid, using the coating composition after 1 hour, 3 hours, and 5 hours, respectively, a base material (material: (ABS, dimensions: length 150 mm, width 60 mm, thickness 20 mm) were coated using a spray gun. The obtained coated surface was allowed to stand at 80 ° C. for 30 minutes to advance the curing reaction, thereby forming a coating film having a thickness of 25 μm. Then, it was left to stand at room temperature for 7 days to completely advance the curing reaction. The following evaluation was performed about the obtained coating film. The evaluation results are shown in Table 2.

(Necessity of dilution)
The coating composition which became unsuitable for coating due to an increase in viscosity formed a coating film in the same manner as described in the coating film performance evaluation using water whose viscosity was adjusted by adding water. The evaluation criteria are as follows. Example 1 and Example 2 did not require dilution even after 5 hours. On the other hand, Comparative Example 1 and Comparative Example 2 needed to be diluted after 3 hours or more.
No: It was possible to paint without diluting (practical level).
Existence: Diluted with water (unsuitable for practical use) because it cannot be painted without dilution.

(appearance)
The appearance of the obtained coating film was visually confirmed. The evaluation criteria are as follows.
○: Smoothness is good and there is no practical problem (practical level).
X: There is a wave and there is a problem in practical use (practical inappropriate level).

(60 ° gloss)
According to JIS K-5400: 1990 “Paint General Test Method”, the 60 ° glossiness of the coating film surface was measured. The glossiness was measured using a gloss meter (model micro-TRI-gloss, manufactured by BYK Gardner). Glossiness means that the greater the value, the higher the gloss.

(Initial adhesion)
According to JIS K5600-5-6: 1999 “Cross Cut Method”, 100 1 mm × 1 mm grid-like cuts were made, and a peel test was performed using an adhesive tape. Evaluation criteria were also evaluated according to the same standard.
○: No peeling (practical level).
X: Peeling of 1 mm or more (unsuitable for practical use).

(Moisture resistance)
After leaving for 240 hours in a constant temperature and humidity chamber with an atmospheric temperature of 50 ° C. and an atmospheric humidity of 95% RH, a peel test with an adhesive tape was performed. The test method and criteria are the same as for the initial adhesion.

(Water adhesion resistance)
After immersion in warm water at 40 ° C. for 240 hours, a peel test using an adhesive tape was performed. The test method and criteria are the same as for the initial adhesion.

Example 3
In the same manner as in Example 1, except that 6.8 parts by mass of diacetone alcohol was changed to 6.8 parts by mass of n-butyl alcohol (logPow: 0.9, boiling point: 117 ° C.) in Example 1. A composition was obtained.

Example 4
In Example 1, 6.8 parts by mass of diacetone alcohol was changed to 6.8 parts by mass of isopropyl alcohol (logPow: 0.05, boiling point: 82 ° C.). Got.

(Example 5)
In Example 1, paint was applied in the same manner as in Example 1 except that 6.8 parts by mass of diacetone alcohol was changed to 6.8 parts by mass of ethylene glycol monobutyl ether (logPow: 0.8, boiling point: 171 ° C.). A composition was obtained.

(Example 6)
The coating composition of Example 1 was referred to as Example 6.

(Comparative Example 3)
The coating composition was the same as in Example 1 except that 6.8 parts by mass of diacetone alcohol in Example 1 was changed to 6.8 parts by mass of n-octanol (logPow: 3.0, boiling point: 194 ° C.). I got a thing.

(Comparative Example 4)
The coating composition was the same as in Example 1 except that 6.8 parts by mass of diacetone alcohol in Example 1 was changed to 6.8 parts by mass of isodecanol (logPow: 3.94, boiling point: 215 to 225 ° C). I got a thing.

  Each of the coating compositions of Examples 3 to 5 and Comparative Examples 3 and 4 was evaluated in the same manner as in Example 1. The evaluation results are shown in Tables 3 and 4.

About Examples 5 and 6 in which the pot life evaluation was good, water resistance was evaluated as an additional evaluation. The water resistance evaluation was the coating composition of Examples 5 and 6, and the coating composition after 5 hours in which the first liquid and the second liquid were mixed was used for each of the base materials (material: ABS, dimensions). : 150 mm long, 60 mm wide, 20 mm thick) was applied using a spray gun. The obtained coated surface was allowed to stand at 80 ° C. for 30 minutes to advance the curing reaction, thereby forming a coating film having a thickness of 25 μm. Then, it was left to stand at room temperature for 7 days to completely advance the curing reaction. About the obtained coating film, the external appearance change of the test piece was confirmed after being immersed in 60 degreeC warm water for 12 hours. The evaluation criteria are as follows. The evaluation results are shown in Table 5.
○: No abnormality ×: Whitening

Claims (6)

A first liquid containing an acrylic polyol resin as a main resin, a dispersoid, an alcohol as an auxiliary agent, and water as a dispersion medium;
A second liquid containing a polyisocyanate resin as a curing agent,
The alcohol is at least one of a primary alcohol having an octanol / water partition coefficient of less than 3.00, a secondary alcohol having an octanol / water partition coefficient of less than 3.47, or a tertiary alcohol;
The acid value of the acrylic polyol resin is 10 to 25 mgKOH / g,
The molar equivalent of the isocyanate group that the polyisocyanate resin has relative to the molar equivalent 1 of the hydroxyl group that the acrylic polyol resin has is 1.5 to 3,
A two-component water-based paint composition, wherein the first liquid and the second liquid are mixed to advance a curing reaction.   The two-component water-based paint composition according to claim 1, wherein the alcohol has a boiling point of 170 ° C. or less.   The two-component water-based paint composition according to claim 1 or 2, wherein the acrylic polyol resin is a colloidal dispersion type.   4. The two-component type according to claim 3, wherein the colloidal dispersion type acrylic polyol resin is a resin dispersed in water by imparting hydrophilicity to the polymer particles themselves without using an emulsifier. Water-based paint composition.   The two-part water-based paint composition according to any one of claims 1 to 4, wherein the tertiary alcohol has an octanol / water partition coefficient of 0.4 or less.   The alcohol is an auxiliary agent for assisting in dispersibility of the polyisocyanate resin in water, an auxiliary agent for extending the pot life of the two-component aqueous coating composition, or an auxiliary agent for adjusting the viscosity of the first liquid. The two-component water-based paint composition according to any one of claims 1 to 5, wherein the two-component water-based paint composition acts as at least one of the following.