JP2007091782A - Cross-linkable water-based coating composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cross-linkable water-based coating composition which does not use an organic solvent, has good storage stability, and forms coating films excellent in coating film appearances (gloss, brightness, and the like), solvent resistance, water resistance, weather resistance, soil resistance, balance between hardness and flexibility, and the like, in short time even at room temperature. <P>SOLUTION: This cross-linkable water-based coating composition is characterized by comprising an aqueous dispersion of a polyol component (A) having a hydroxyl group value of 10 to 200mgKOH/g, a polyisocyanate compound (B), and a urethanization reaction catalyst (C), wherein the equivalent ratio of [the isocyanate groups of the polyisocyanate compound (B)]/[the hydroxyl groups of the polyol component (A)] is 0.1 to 5.0, and the urethanization reaction catalyst (C) exists in the polyol component (A) dispersed in water in an amount of 5 to 10,000 ppm per mass of the polyol component (A). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention provides storage stability (pot life) capable of forming a coating film having excellent performance in various properties of the coating film such as weather resistance, stain resistance, gloss, sharpness, hardness, flex resistance, and solvent resistance. It is related with the crosslinkable water-based coating composition excellent in).

In recent years, with the increasing demand for solvent removal from paints, various water-based paints have been actively researched, but still have sufficient physical properties in terms of water resistance, stain resistance, hardness, etc. compared to organic solvent-based paints. Not shown.
For the purpose of improving these physical properties, it is a common practice to introduce a functional group into a water-based paint to form a crosslinked coating film. Among these, a urethane cross-linked coating film produced from a cross-linkable water-based paint composed of a water-based resin into which a hydroxyl group is introduced and an isocyanate curing agent is attracting attention because it exhibits excellent physical properties such as solvent resistance and weather resistance ( Patent Document 1, Patent Document 2, etc.).

However, in the water-based paint using urethane cross-linking, since the urethanization reaction rate between the hydroxyl group of the water-based resin (main agent) and the isocyanate group of the curing agent is slow near room temperature, the coating film obtained in the on-site coating is cross-linked. There was a problem that it took a very long time to develop good physical properties.
In general, attempts to add a urethanization reaction catalyst have been made to deal with this problem. However, the urethanization reaction catalyst also promotes the reaction between water and the isocyanate group of the curing agent. The storage stability (pot life) of water-based paints containing an agent and a urethanization reaction catalyst is very short and has a problem that workability is very poor.
Japanese Patent Laid-Open No. 2-105879 JP-A-6-17004

  The present invention does not use an organic solvent, has good storage stability, and has a coating film appearance (gloss, sharpness, etc.), solvent resistance, water resistance, weather resistance, stain resistance, even at room temperature in a short time. It is an object of the present invention to provide a crosslinkable aqueous coating composition that forms a coating film having an excellent balance between hardness and flexibility (flexibility, etc.).

  As a result of intensive studies, the present inventors distributed the urethanization reaction catalyst (C) to the polyol component (A) particles in the aqueous dispersion of the polyol component (A) having a specific hydroxyl value, and the polyisocyanate. The crosslinkable aqueous coating composition obtained by blending the compound (B) has been found to achieve both storage stability and rapid coating properties, and has led to the present invention.

That is, the present invention is as follows.
1. It comprises an aqueous dispersion of a polyol component (A) having a hydroxyl value of 10 to 200 mgKOH / g, a polyisocyanate compound (B), and a urethanization reaction catalyst (C), and [isocyanate group of polyisocyanate compound (B)] / The equivalent ratio of [hydroxyl group of the polyol component (A)] is 0.1 to 5.0, and the urethanization reaction catalyst (C) is dispersed in water in the polyol component (A). A crosslinkable aqueous coating composition characterized in that it is present in an amount of 5 to 10,000 ppm relative to the mass of A).
2. The crosslinkable aqueous coating composition according to claim 1, wherein the polyisocyanate compound (B) is a water-dispersible polyisocyanate composition (B1).
3. 3. The polystyrene-converted molecular weight distribution dispersion ratio (weight average molecular weight / number average molecular weight) of the polyol component (A) measured by gel permeation chromatography is 3.5 or more. A crosslinkable aqueous coating composition as described in 1. above.

4). The polyol component (A) is a core phase (A1) having a polystyrene-equivalent number average molecular weight of 100,000 or more measured by gel permeation chromatography and a polystyrene-equivalent number average molecular weight measured by gel permeation chromatography. A core / shell polymer comprising a shell phase (A2) of 3000 to 100,000, wherein the mass ratio is (A2) / (A1) = 9/1 to 1/9. 4. The crosslinkable aqueous coating composition according to any one of 3 above.
5. The crosslinkable aqueous coating composition according to any one of claims 1 to 4, wherein the urethanization catalyst (C) is an organotin compound.

  The crosslinkable water-based coating composition of the present invention has good storage stability, and without using an organic solvent, the coating film appearance (gloss, sharpness, etc.) and solvent resistance, which were disadvantages of conventional aqueous paints. The coating film properties excellent in water resistance, weather resistance, stain resistance, balance between hardness and flexibility (flexibility, etc.), etc. can be expressed early after coating.

Hereinafter, the present invention will be described in detail.
The crosslinkable aqueous coating composition of the present invention comprises an aqueous dispersion of a polyol component (A), a polyisocyanate compound (B), a urethanization reaction catalyst (C), and the urethanization reaction catalyst (C) The polyol component (A) dispersed in water is present in an amount of 5 to 10,000 ppm based on the mass of the polyol component (A).
In the present invention, the crosslinkable aqueous coating composition of the present invention is storage stable by containing 5 to 10,000 ppm, preferably 10 to 5000 ppm of the urethanization reaction catalyst (C) in the polyol component (A) dispersed in water. It is possible to express early coating properties after coating.

That is, when the amount of the urethanization reaction catalyst (C) is 5 ppm or less, it takes time to develop the physical properties of the coating film obtained from the crosslinkable aqueous coating composition of the present invention. The storage stability of the crosslinkable aqueous coating composition is deteriorated. In particular, when an organotin compound having a large urethanization reaction catalyst activity described later is used as the urethanization reaction catalyst (C), the amount used is 5 to 5000 ppm based on the mass of the polyol component (A). It is preferable from the viewpoint of achieving both storage stability and early physical properties.
The crosslinkable aqueous coating composition of the present invention is preferably prepared by mixing an aqueous dispersion of a polyol component (A) containing a urethanization reaction catalyst (C) and a polyisocyanate compound (B). it can.

Here, the aqueous dispersion of the polyol component (A) containing the urethanization reaction catalyst (C) is:
[I] A method in which an aqueous dispersion of the polyol component (A) and the urethanization reaction catalyst (C) are mixed, and preferably stirred at 10 to 90 ° C., and [II] an aqueous dispersion of the polyol component (A) is produced. In the process of mixing the monomer component constituting the polyol component and the urethanization reaction catalyst (C),
However, it is also possible to carry out a combination of the above methods, and is not limited to the above two methods.

In the method [I], the stirring time after mixing the aqueous dispersion of the polyol component (A) and the urethanization reaction catalyst (C) is the same as the aqueous dispersion of the urethanization reaction catalyst (C) in the polyol component (A). There is no particular limitation as long as it is sufficient to distribute the water, but for example, when the temperature of mixing the aqueous dispersion of the polyol component (A) and the urethanization reaction catalyst (C) is around room temperature (0 to about 40 ° C.) The stirring time after mixing is preferably 1 hour or longer, and more preferably 6 hours or longer. When the mixing temperature is relatively high (about 40 to 90 ° C.), the stirring time after mixing is preferably 10 minutes or more, and more preferably 30 minutes or more and 12 hours or less.
In addition, an aqueous dispersion of the polyol component (A) containing the urethanization reaction catalyst (C) preferably used for adjusting the crosslinkable aqueous coating composition of the present invention is a urethanization reaction catalyst ( It is most preferable from the viewpoint of storage stability that C) is substantially absent (1 ppm or less with respect to the mass of the aqueous phase).

In the present invention, the quantification of the urethanization reaction catalyst (C) present in the polyol component (A) of the aqueous dispersion of the polyol component (A) is performed, for example, from the aqueous dispersion of the polyol component (A) to the polyol component (A). Is separated by centrifugation, etc., and the polyol component (A) and the urethanization reaction catalyst (C) in the aqueous phase are analyzed using analytical techniques such as elemental analysis and inductively coupled plasma emission spectroscopy (ICP-AES). Is possible.
In the present invention, the polyol component (A) includes an acrylic polymer, a fluoroolefin polymer, a vinyl ester polymer, an aromatic vinyl polymer, a polyolefin polymer, a polyester polymer, and an alkyd polymer. And polyurethane polymers, among which vinyl copolymers such as acrylic polymers and fluoroolefin polymers are preferred.

The hydroxyl value of the polyol component (A) used in the present invention is 10 to 200 mgKOH / g, preferably 30 to 150 mgKOH / g.
In the polyol component (A) of the present invention, when the hydroxyl value is 10 mgKOH / g or more, the amount of crosslinking points is sufficient for the development of good coating film properties, while the initial water resistance is good at 200 mgKOH / g or less, and the coating viscosity The workability is also good.
The acid value of the polyol component (A) of the present invention is preferably 0 to 50 mgKOH / g, more preferably 2 to 20 mgKOH / g. The acid value is 50 mgKOH / g or less, and the water resistance of the coating film is good.
Here, the hydroxyl value is the number of mg of potassium hydroxide required for acetylating the hydroxyl group in 1 g of resin with acetic anhydride and neutralizing the acetic acid produced by acetylation. The acid value is the number of mg of potassium hydroxide required to neutralize the free acid in 1 g of resin. These hydroxyl value and acid value can also be obtained by calculation from the amount of the hydroxyl group-containing monomer and acid group-containing monomer used when synthesizing the polyol component (A).

In the present invention, when the polyol component (A) is composed of a mixture of different hydroxyl value and / or acid value polyols, it is preferable that the hydroxyl value and acid value of the polyol component (A) as a mixture are within the above ranges. .
Furthermore, the glass transition temperature of the polyol component (A) of the present invention is preferably in the range of −60 to 120 ° C., more preferably in the range of −40 to 80 ° C. When the glass transition temperature is -60 ° C or higher, the coating film is excellent in water resistance and stain resistance. On the other hand, when the glass transition temperature is 120 ° C or lower, it is not necessary to use an excessive amount of plasticizer or organic solvent for film formation. Therefore, it is preferable in terms of the environment, and further, the initial drying property is good, and the coating cracking over time is less likely to occur. Here, the glass transition temperature may be measured by viscoelasticity measurement, differential scanning calorimetry, or the like, or a commonly used calculation method [for example, Bull. Am. Phys. Soc. , Vol. 1, No. 1 3, 123 (1956) etc.].

In the present invention, when the polyol component (A) comprises a mixture of polyols having different glass transition temperatures, the glass transition temperature of each polyol constituting the polyol component (A) is preferably within the above range.
The number average molecular weight of the polyol component (A) used in the present invention is preferably 10,000 to 500,000, more preferably 15,000 to 150,000, and still more preferably 50,000 to 100,000. In this case, from the crosslinkable aqueous coating composition of the present invention containing the polyol component (A) and the polyisocyanate compound (B) described later, the appearance of the coating film (gloss, sharpness) can be obtained without using an organic solvent. Etc.), solvent resistance, water resistance, weather resistance, and stain resistance can be formed. In particular, when the number average molecular weight is 50000 or more, the solvent resistance, water resistance, weather resistance, and contamination resistance are remarkably improved.

When the polyol component (A) has a number average molecular weight of 10,000 or more, the solvent resistance, water resistance, weather resistance, and stain resistance of the coating film obtained from the crosslinkable aqueous coating composition of the present invention are preferably increased. Since these coating film properties are further improved when there are few low molecular weight polyol components having a molecular weight in terms of polystyrene of less than 2000, in the present invention, low molecular weight polyols having a molecular weight in terms of polystyrene of less than 2000 in the polyol component (A). The component content is preferably less than 3% by mass.
On the other hand, when the number average molecular weight of the polyol component (A) is 300,000 or less, the coating film appearance (gloss, sharpness, etc.) is improved, which is preferable. It is particularly preferable that the number average molecular weight of the polyol component (A) is 100,000 or less because the appearance of the coating film is very excellent.

Moreover, when the molecular weight distribution dispersion ratio (weight average molecular weight / number average molecular weight) of the polyol component (A) is 3.5 or more, the crosslinkable aqueous coating composition of the present invention does not need to use an organic solvent. It is possible to form a coating film having a very good balance between hardness and flexibility (flexibility, etc.). This effect can be remarkably exhibited when the molecular weight distribution dispersion ratio (weight average molecular weight / number average molecular weight) of the polyol component (A) is 4 or more, preferably 5 or more, more preferably 10 or more.
The aqueous dispersion of the polyol component (A) of the present invention is preferably obtained by solvent substitution after suspension polymerization, emulsion polymerization or solution polymerization, and more preferably has a hydroxyl group-containing vinyl monomer (I) as an essential component. It can be obtained by emulsion polymerization or suspension polymerization of a vinyl monomer. From the viewpoints of weather resistance, stain resistance, etc., the polyol component (A) is most preferably an acrylic emulsion.

  The aqueous dispersion of the polyol component (A) that can be suitably used in the present invention is preferably 0.3 to 60% by mass of the hydroxyl group-containing vinyl monomer (A) and other vinyl monomers copolymerizable therewith. (B) It is obtained by polymerizing 40 to 99.7% by mass in the presence or absence of an emulsifier in water or a water-miscible organic solvent / water mixed solvent, preferably in the presence of a radical polymerization catalyst. . At this time, the hydroxyl group-containing vinyl monomer (i) and the other vinyl monomer (b) copolymerizable therewith are either as they are or in an emulsified state in a batch, divided, or continuously in a reaction vessel. The reaction solution may be added dropwise and polymerized in the presence of the radical polymerization catalyst, preferably at a pressure of 10 MPa and a reaction temperature of about 50 to 150 ° C. from atmospheric pressure if necessary. In some cases, the polymerization may be carried out even at a higher pressure or lower temperature. The ratio between the total vinyl monomer amount and water is preferably set so that the final solid content is in the range of 1 to 60% by mass, preferably 15 to 55% by mass.

  In addition, in order to grow or control the particle diameter in emulsion polymerization, a seed polymerization method in which emulsion particles are previously present in the aqueous phase for polymerization may be used. The polymerization reaction may be allowed to proceed in the range of pH in the system of preferably 1.0 to 10.0, more preferably 1.0 to 6.0. The pH can be adjusted by using a pH buffer such as disodium phosphate, borax, sodium hydrogen carbonate, or ammonia.

  In the present invention, examples of the hydroxyl group-containing vinyl monomer (A) used for synthesizing the aqueous dispersion of the polyol component (A) include 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth). Hydroxyalkyl esters of (meth) acrylic acid such as acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, Number of di-2-hydroxyethyl fumarate, mono-2-hydroxyethyl monobutyl fumarate, allyl alcohol and ethylene oxide groups of 1 to 100 (poly) oxyethylene mono (meth) acrylates, propylene oxide groups 1 to 100 (poly) oxy Lopylene mono (meth) acrylate, “Plexel FM, FA monomer” [trade name of caprolactone addition monomer manufactured by Daicel Chemical Industries, Ltd.] and other hydroxyalkyl esters of α, β-ethylenically unsaturated carboxylic acids And the like.

  Specific examples of the (poly) oxyethylene (meth) acrylate include ethylene glycol (meth) acrylate, ethylene glycol methoxy (meth) acrylate, diethylene glycol (meth) acrylate, diethylene glycol methoxy (meth) acrylate, (meth ) Tetraethylene glycol acrylate, tetraethylene glycol methoxy (meth) acrylate, and the like. Specific examples of (poly) oxypropylene (meth) acrylate include propylene glycol (meth) acrylate, propylene glycol methoxy (meth) acrylate, dipropylene glycol (meth) acrylate, dimethoxy meth (meth) acrylate. Examples include propylene glycol, tetrapropylene glycol (meth) acrylate, and tetrapropylene glycol methoxy (meth) acrylate.

  The hydroxyl group-containing vinyl monomer (a) mentioned above is preferably 0.3 to 60% by mass, more preferably 1.0 to 50% by mass in the total vinyl monomer as one or a mixture of two or more. More preferably, it is 3.0-30 mass%. When the amount is 0.3% by mass or more, the amount of hydroxyl group introduced is sufficient, crosslinking between particles and within the particles can be sufficiently performed, and water resistance, solvent resistance, contamination resistance, and weather resistance are good. Since the amount of crosslinking is moderate at 60% by mass or less, the coating film does not become too hard or brittle, and the water resistance of the coating film is good.

  Examples of other vinyl monomers (b) copolymerizable with the hydroxyl group-containing vinyl monomer (a) include acrylic acid esters, methacrylic acid esters, acrylamide monomers, methacrylamide monomers, and aromatics. In addition to vinyl compounds and vinyl cyanides, carboxyl group-containing vinyl monomers, anionic vinyl monomers, hydrolyzable silyl group-containing vinyl monomers, epoxy group-containing vinyl monomers, carbonyl group-containing vinyl monomers Examples thereof include monomers containing a functional group such as a monomer.

  Examples of the (meth) acrylic acid ester include (meth) acrylic acid alkyl ester having 1 to 18 carbon atoms in the alkyl portion and (poly) oxyethylene di (meth) having 1 to 100 ethylene oxide groups. An acrylate etc. are mentioned. Specific examples of (meth) acrylic acid esters include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and methyl (meth) acrylate. Examples include cyclohexyl, cyclohexyl (meth) acrylate, lauryl (meth) acrylate, dodecyl (meth) acrylate, and the like. Specific examples of (poly) oxyethylene di (meth) acrylate include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, diethylene glycol methoxy (meth) acrylate, tetraethylene glycol di (meth) acrylate Etc.

  Examples of the (meth) acrylamide monomer include (meth) acrylamide, N-methyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N-ethyl (meth) acrylamide, and Nn-propyl ( Examples thereof include meth) acrylamide, N-isopropyl (meth) acrylamide, Nn-butyl (meth) acrylamide and the like.

  Examples of the carboxyl group-containing vinyl monomer include acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, maleic anhydride, or half of a dibasic acid such as itaconic acid, maleic acid, and fumaric acid. Esters and the like. By using a carboxylic acid group-containing vinyl monomer, a carboxyl group can be introduced into the polyol component (A) constituting the aqueous emulsion, and a part or all of the introduced carboxyl group can be converted into ammonia, triethylamine, dimethylethanol. By neutralizing with amines such as amines or bases such as NaOH or KOH, it is possible to improve the stability as an aqueous emulsion and to have a resistance to dispersion and destruction from the outside. The presence of the carboxyl group also has an effect of accelerating the crosslinking reaction between the polyol component (A) and the polyisocyanate compound described later, and is useful for early development of good coating film properties.

  The amount of the carboxyl group-containing vinyl monomer used is preferably 0 to 30% by mass, more preferably 0.1 to 10% by mass, and still more preferably 0.1 to 5% by mass in all vinyl monomers. . If it exceeds 30% by mass, the water resistance of the coating film may be lowered, which is not preferable.

  Examples of the anionic vinyl monomer include a vinyl monomer having a sulfonic acid group or a sulfonate group, a vinyl monomer having a sulfate group, and the like. A vinyl monomer having a sulfonic acid group or a sulfonate group is a carbon having a radical polymerizable double bond and partially substituted with a group which is an ammonium salt, sodium salt or potassium salt of a sulfonic acid group. A substituent selected from the group consisting of an alkyl group having 1 to 20 carbon atoms, an alkyl ether group having 2 to 4 carbon atoms, a polyalkyl ether group having 2 to 4 carbon atoms, an aryl group having 6 or 10 carbon atoms, and a succinic acid group. Or a vinyl sulfonate compound having a vinyl group to which a group which is an ammonium salt, sodium salt or potassium salt of a sulfonic acid group is bonded. The vinyl monomer having a sulfate ester group has a radically polymerizable double bond and is partially substituted by a group that is an ammonium salt, sodium salt or potassium salt of a sulfate ester group, having 1 to 1 carbon atoms. It is a compound having a substituent selected from the group consisting of 20 alkyl groups, alkyl ether groups having 2 to 4 carbon atoms, polyalkyl ether groups having 2 to 4 carbon atoms, and aryl groups having 6 or 10 carbon atoms.

Specific examples of the compound having a succinic acid group partially substituted with a group which is an ammonium salt, sodium salt or potassium salt of the sulfonic acid group include allyl sulfosuccinate. Specific examples thereof include, for example, Eleminol JS-2 (trade name) (manufactured by Sanyo Kasei Co., Ltd.), Latemuru S-120, S-180A or S-180 (trade name) (manufactured by Kao Corporation), and the like. Can be mentioned.
Further, a compound having an alkyl ether group having 2 to 4 carbon atoms or a polyalkyl ether group having 2 to 4 carbon atoms, which is partially substituted by a group which is an ammonium salt, sodium salt or potassium salt of the sulfonic acid group. As specific examples, for example, Aqualon HS-10 or KH-1025 (trade name) (Daiichi Kogyo Seiyaku Co., Ltd.), Adekaria soap SE-1025N or SR-1025 (trade name) (Asahi Denka Kogyo Co., Ltd.) And the like.

Other specific examples of the compound having an aryl group partially substituted with a sulfonate group include ammonium salt, sodium salt and potassium salt of p-styrenesulfonic acid.
Examples of the vinyl sulfonate compound having a vinyl group to which a group of ammonium salt, sodium salt or potassium salt of the sulfonic acid group is bonded include, for example, alkyl sulfonic acid (meth) acrylate such as 2-sulfoethyl acrylate, and methylpropane sulfonic acid. Examples thereof include ammonium salts such as (meth) acrylamide and allylsulfonic acid, sodium salts, and potassium salts.

  Examples of the compound having an alkyl ether group having 2 to 4 carbon atoms or a polyalkyl ether group having 2 to 4 carbon atoms partially substituted with the ammonium salt, sodium salt or potassium salt of the sulfate ester group include, for example, Examples include compounds having an alkyl ether group partially substituted with a sulfonate group.

By using the above-mentioned anionic vinyl monomer, an anionic group can be introduced into the polyol component (A) constituting the aqueous emulsion, thereby improving the stability of the aqueous emulsion or reducing the viscosity of the aqueous emulsion. be able to. The interaction with the improvement of the stability of the aqueous emulsion due to the introduction of the carboxyl group described above is preferable because the chemical stability against the dispersion breaking action such as addition of water-dispersed polyisocyanate can be drastically improved.
The amount of the anionic vinyl monomer used is preferably 0 to 30% by mass, more preferably 0.1 to 10% by mass, and still more preferably 0.1 to 5% by mass in the total vinyl monomers. If it exceeds 30% by mass or less, the coating film has good water resistance, which is preferable.

  Examples of the hydrolyzable silyl group-containing vinyl monomer include vinyltrimethoxysilane, vinyltriethoxysilane, vinylmethyldimethoxysilane, vinyltris (2-methoxyethoxy) silane, allyltrimethoxysilane, 2-trimethyl. Methoxysilylethyl vinyl ether, 3-trimethoxysilylpropyl vinyl ether, 3- (methyldimethoxysilyl) propyl vinyl ether, 3- (meth) acryloyloxypropyltrimethoxysilane, 3- (meth) acryloyloxypropyltriethoxysilane, 3- ( (Meth) acryloyloxypropylmethyldimethoxysilane, 3- (meth) acryloyloxypropyltri-n-propoxysilane, 3- (meth) acryloyloxypropyltriiso-propoxysilane 3- (meth) acrylate can be exemplified acryloyl the like propyl methyl dichlorosilane.

Examples of the glycidyl group-containing vinyl monomer include glycidyl (meth) acrylate, allyl glycidyl ether, and allyl dimethyl glycidyl ether.
By using the hydrolyzable silyl group-containing vinyl monomer or glycidyl group-containing vinyl monomer described above, a hydrolyzable silyl group or glycidyl group can be introduced into the polyol component (A) constituting the aqueous emulsion. By reacting the hydroxyl group, carboxyl group, hydrolyzable silyl group, and glycidyl group described above, the crosslinking reaction in the particles of the aqueous emulsion is advanced to improve the gel fraction, and a coating film with excellent water resistance can be obtained. Can be obtained.

  Examples of the carbonyl group-containing vinyl monomer include acrolein, diacetone acrylamide, diacetone methacrylamide, formyl styrene, vinyl methyl ketone, vinyl ethyl ketone, vinyl isobutyl ketone, acryloxyalkylpropanals, methacryloxyalkylpropanal. , Diacetone acrylate, diacetone methacrylate, acetonyl acrylate, 2-hydroxypropyl acrylate acetyl acetate, butanediol acrylate acetyl acetate, acetone dicarboxylic acid, dihydroxyacetone, monohydroxyacetone, and dihydroxybenzaldehyde. Vinyl monomers containing carbonyl groups of acids and esters are excluded.

  Specific examples of vinyl monomers (b) other than the above include olefins such as ethylene, propylene and isobutylene, dienes such as butadiene, vinyl chloride, vinylidene chloride, tetrafluoroethylene, chlorotri Haloolefins such as fluoroethylene, vinyl acetate, vinyl propionate, vinyl n-butyrate, vinyl benzoate, vinyl pt-butylbenzoate, vinyl pivalate, vinyl 2-ethylhexanoate, vinyl versatate, lauric acid Carboxylic acid vinyl esters such as vinyl, isopropenyl acetate, isopropenyl propionate, etc., vinyl ethers such as ethyl vinyl ether, isobutyl vinyl ether, cyclohexyl vinyl ether, styrene, vinyl toluene, etc. Aromatic vinyl compounds, allyl esters such as allyl acetate and allyl benzoate, allyl ethers such as allyl ethyl ether and allyl phenyl ether, γ- (meth) acryloxypropyltrimethoxysilane, 4- (meth) acryloyloxy -2,2,6,6, -tetramethylpiperidine, 4- (meth) acryloyloxy-1,2,2,6,6, -pentamethylpiperidine, perfluoromethyl (meth) acrylate, perfluoropropyl (meta ) Acrylate, perfluoropropylmethyl (meth) acrylate, vinylpyrrolidone, trimethylolpropane tri (meth) acrylate, allyl (meth) acrylate, and the like, and combinations thereof.

  Examples of emulsifiers that can be used in the synthesis of the aqueous emulsion of the present invention include fatty acid soaps, alkyl sulfonates, alkyl sulfosuccinates, polyoxyethylene alkyl sulfates, polyoxyethylene alkyl aryl sulfates, and polyoxy Anionic surfactants such as ethylene distyryl phenyl ether sulfonate and quaternary ammonium salts such as alkyltrimethylammonium bromide, alkylpyridinium bromide, imidazolinium laurate, pyridinium salt, imidazolinium salt type Surfactant, polyoxyethylene alkyl aryl ether, polyoxyethylene sorbitan fatty acid ester, oxyethylene oxypropylene block copolymer, polyoxyethylene distyryl phenyl ester Non-reactive nonionic surfactants such as ter, α- [1-[(allyloxy) methyl] -2- (nonylphenoxy) ethyl] -ω-hydroxypolyoxyethylene (trade name: Adecalia Soap NE-20, NE-30, NE-40, etc., manufactured by Asahi Denka Kogyo Co., Ltd., polyoxyethylene alkylpropenyl phenyl ether (trade names: Aqualon RN-10, RN-20, RN-30, RN-50, etc., Daiichi Pharmaceutical Nonionic surfactants copolymerized with ethylenically unsaturated monomers, which are called reactive nonionic surfactants such as those manufactured by Kogyo Co., Ltd., are used.

As the usage-amount of the said emulsifier, the inside of the range used as 10 mass parts or less is suitable with respect to 100 mass parts of total vinyl monomers, Especially, the inside which becomes 0.1-5 mass parts is preferable. .
In addition to the above emulsifiers, a dispersion stabilizer may be used for the purpose of improving the stability of the aqueous dispersion of the polyol component (A) of the present invention. Examples of the dispersion stabilizer include various water-soluble oligomers selected from the group consisting of polycarboxylic acids and sulfonates, polyvinyl alcohol, hydroxyethyl cellulose, starch, maleated polybutadiene, maleated alkyd resin, polyacrylic acid (salt ), Synthetic or natural water-soluble or water-dispersible water-soluble polymer substances such as polyacrylamide, water-soluble or water-dispersible acrylic resin, etc., and one or a mixture of two or more of these are used. be able to.

The amount of these dispersion stabilizers used is suitably within a range of 10 parts by mass or less with respect to 100 parts by mass of the total vinyl monomer, and in particular, within a range of 0.1 to 5 parts by mass. The inside is preferable.
Further, the radical polymerization catalyst that can be used for the synthesis of the aqueous dispersion of the polyol component (A) is one that causes radical polymerization by heat or a reducing substance to cause addition polymerization of the vinyl monomer. Alternatively, oil-soluble persulfates, peroxides, azobis compounds and the like are used. Examples include potassium persulfate, sodium persulfate, ammonium persulfate, hydrogen peroxide, t-butyl hydroperoxide, t-butyl peroxybenzoate, 2,2-azobisisobutyronitrile, 2,2-azobis. There are (2-diaminopropane) hydrochloride, 2,2-azobis (2,4-dimethylvaleronitrile), and the amount thereof is 0.001 to 5 parts by mass with respect to 100 parts by mass of all vinyl monomers. Is preferable. When acceleration of the polymerization rate and polymerization at a low temperature of 70 ° C. or lower are desired, it is advantageous to use a reducing agent such as sodium bisulfite, ferrous chloride, ascorbate, or longalite in combination with the radical polymerization catalyst. is there.

In the present invention, the polymerization conversion rate of the vinyl monomer at the end of the polymerization is preferably 95% or more, more preferably 98% or more, and further preferably substantially 100%.
In addition, the said polymerization conversion rate shall mean the mass% of the vinyl monomer taken in in the polymer by polymerization reaction. That is, the polymerization conversion rate (%) is a value obtained by dividing the solid content concentration (actual value) of the polymerization solution at a certain point by the theoretical solid content concentration calculated on the assumption that the polymerization has completely progressed. Multiplied by 100.

In the present invention, the range of the number average molecular weight and the molecular weight distribution dispersion ratio (weight average molecular weight / number average molecular weight) of the polyol component (A) are preferably set to the specific values as described above.
When the polyol component (A) is a vinyl copolymer (more preferably the aqueous emulsion) which is a preferred form in the present invention, the adjustment of the number average molecular weight is performed by adjusting the amount of the radical polymerization catalyst and the reaction temperature. Further, it can be adjusted by using a chain transfer agent. Among these, adjustment of the number average molecular weight with a chain transfer agent is the simplest and preferable.

  Examples of such chain transfer agents include alkyl mercaptans such as n-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan; aromatic mercaptans such as benzyl mercaptan and dodecyl benzyl mercaptan; thiocarboxylic acids such as thiomalic acid, or Examples thereof include salts thereof, alkyl esters thereof, polythiols, diisopropylxanthogen disulfide, di (methylenetrimethylolpropane) xanthogen disulfide and thioglycol, and allyl compounds such as a dimer of α-methylstyrene. .

The amount of these chain transfer agents used depends on the amount of radical polymerization catalyst used and the reaction temperature, but is preferably 0.001 to 30% by mass, more preferably 0.05 to 10%, based on the total vinyl monomer. It can be used in the range of mass%.
In addition, the molecular weight distribution dispersion ratio (weight average molecular weight / number average molecular weight) of the polyol component (A) of the present invention, preferably a vinyl copolymer, is determined by the amount of the radical polymerization catalyst, the amount of the chain transfer agent, The chain transfer agent species and / or the reaction temperature can be adjusted by polymerizing in multiple stages under different conditions. Among these, the method of polymerizing vinyl monomer compositions containing different amounts of chain transfer agent and / or different chain transfer agent types in multiple stages is the molecular weight distribution dispersion ratio (weight average molecular weight of the polyol component (A). / Number average molecular weight) is the most effective and preferable method for adjusting.

  Here, the method of polymerizing vinyl monomer compositions containing different amounts of chain transfer agent and / or different chain transfer agent types in multiple stages (hereinafter referred to as chain transfer agent multistage polymerization) is the same composition or different. Two or more types of vinyl monomer compositions are prepared by adding different amounts and / or types of chain transfer agents to the vinyl monomer mixture having different compositions, and these are polymerized in separate stages. Means that. The chain transfer agent multistage polymerization also includes a so-called power feed polymerization in which the vinyl monomer composition is polymerized while continuously changing the chain transfer agent amount and / or the chain transfer agent species.

Below, the synthesis | combination of the polyol component (A) by the said chain transfer agent multistage polymerization is demonstrated to an example of the synthesis | combination of the aqueous dispersion of the polyol component (A) by two-stage polymerization.
In the present invention, the synthesis of the aqueous dispersion of the polyol component (A) by the above-mentioned two-stage polymerization is the first-stage polymerization in which the vinyl monomer system [1] selected from the vinyl monomers described above is supplied and emulsion polymerization is performed. Then, following the first stage, a vinyl monomer system [2] selected from the vinyl monomers described above is supplied and obtained by a two-stage polymerization process comprising a second stage polymerization in which emulsion polymerization is carried out in an aqueous medium. . As long as this requirement is satisfied, the second stage polymerization is carried out in two or more stages (for example, by changing the composition of the vinyl monomer system [2] sequentially, stepwise or continuously). You can also At this time, the mass ratio between the total amount of vinyl monomers (M1) in the vinyl monomer system [1] and the amount of vinyl monomers (M2) in the vinyl monomer system [2] is preferably (M1) / (M2) = 9/1 to 1/9, more preferably 8/2 to 2/8, still more preferably 7/3 to 3/7. Furthermore, it is preferable that the total vinyl monomer composition used in the first and second stages is within the range of the vinyl monomer composition described above, and each vinyl unit used in the first and second stages within the range satisfying the condition. The composition of the body can be designed arbitrarily.

Here, the vinyl monomer system refers to those containing water, a water-miscible organic solvent, a chain transfer agent, an emulsifier, a dispersion stabilizer, a radical polymerization catalyst, and the like in addition to the vinyl monomer described above.
In the chain transfer agent multistage polymerization, the amount and / or chain transfer agent species contained in the vinyl monomer system [1] supplied in the first stage, and the vinyl monomer system [2] supplied in the second stage. It is important that the amount of chain transfer agent and / or the type of chain transfer agent contained in is different. At this time, in order to obtain an aqueous emulsion having a molecular weight distribution dispersion ratio (weight average molecular weight / number average molecular weight) of 3.5 or more according to the present invention, chain transfer agents having different chain transfer efficiencies in the first stage and the second stage. It is also effective to use a vinyl monomer system containing benzene, but a method using vinyl monomer systems having different chain transfer agent contents in the first stage and the second stage is simple, efficient and preferable.

In the method using vinyl monomer systems having different chain transfer agent contents in the first stage and the second stage, the chain transfer agent amount (% by mass) in the vinyl monomer composition contained in the vinyl monomer system The difference between the first stage and the second stage is preferably 0.001 to 30% by mass, more preferably 0.05 to 10% by mass.
Further, in the synthesis of the aqueous emulsion by the above two-stage polymerization, by selecting a vinyl monomer system containing vinyl monomer compositions having different hydrophilic properties in the first stage and the second stage, the polyol component (A) The aqueous dispersion can be a core / shell polymer.
The synthesis of core / shell polymers is well known in polymer chemistry, for example Progress in Polymer Science by Ishizu, Vol. 23, pp. 1383-1408 (1998).

  In the synthesis of the core / shell polymer, the vinyl monomer composition in the first stage vinyl monomer system [1] is more hydrophilic than the vinyl monomer composition in the second stage vinyl monomer system [2]. (For example, the content ratio of the hydroxyl group-containing vinyl monomer and / or the carboxyl group-containing vinyl monomer is large), the polymer of the first-stage vinyl monomer system [1] is a shell on the particle surface. The second-stage vinyl monomer-based [2] polymer becomes the core phase inside the particles. Such a polymerization method is generally called phase inversion polymerization. [For example, US Pat. No. 4,876,313, J. Pat. Poly. Sci. , Vol. 21, 147 (1983) etc.]

Conversely, the vinyl monomer composition in the second stage vinyl monomer system [2] is more hydrophilic (for example, containing a hydroxyl group) than the vinyl monomer composition in the first stage vinyl monomer system [1]. The content of the vinyl monomer and / or carboxyl group-containing vinyl monomer is high), the second-stage vinyl monomer-based polymer [1] becomes the shell phase on the particle surface, and the first-stage The vinyl monomer type [2] polymer becomes the core phase inside the particles. Such a polymerization method is generally called encap polymerization. [See, for example, US Pat. No. 4,916,171, etc.]
The core / shell polymer in the present invention refers to an aqueous dispersion of all polyol components (A) obtained according to the above-described method for synthesizing a core / shell polymer.

In the present invention, the preferred core / shell polymer is characterized in that the particle size of the polymer particles obtained by the first stage polymerization is not greatly changed in the particle size distribution (volume average particle size / number average particle size). (Preferably in a monodispersed state), it can be increased by the second-stage polymerization (increase in particle diameter).
The phase separation structure of the core / shell polymer can be confirmed by selecting the vinyl monomer species to be used and by devising post-treatment, for example, by morphological observation using a transmission electron microscope or analysis by viscoelasticity measurement. It is also possible to implement.

  In the present invention, the polyol component (A) has a core phase (A1) having a number average molecular weight of 100,000 or more (which may have a crosslinked structure) and a number average molecular weight of 3000 to 100,000, preferably a number average molecular weight of 5000 to 80000. A core / shell polymer comprising a shell phase (A2), the mass ratio of which is (A2) / (A1) = 9/1 to 1/9, preferably 8/2 to 2/8, more preferably 7 / 3 to 3/7, from the crosslinkable aqueous coating composition of the present invention comprising the polyisocyanate compound (B) described later, the appearance of the coating film (gloss, sharpness) without using an organic solvent. Etc.), solvent resistance, water resistance, weather resistance, stain resistance, and a coating film having a very good balance between hardness and flexibility (flexibility, etc.) can be formed.

Such an aqueous dispersion of the polyol component (A) preferably contains a vinyl monomer composition having different hydrophilicity in the first stage and the second stage, such as phase inversion polymerization or encap polymerization described above. Can be easily obtained by two-stage emulsion polymerization using a vinyl monomer system.
That is, a vinyl monomer composition having a relatively high hydrophilicity (for example, a high content ratio of a hydroxyl group-containing vinyl monomer and / or a carboxyl group-containing vinyl monomer) that gives a polymer to be a shell phase (A2) The core satisfying the above number average molecular weight condition by increasing the chain transfer agent content and decreasing the chain transfer agent content in the vinyl monomer composition that gives the polymer to be the core phase (A1) / The polyol component (A) which is a shell polymer can be synthesized.
Here, the chain transfer agent content in the vinyl monomer composition giving the polymer to be the shell phase (A2) is preferably 0.01 to 30% by mass, more preferably 0.05 to 10% by mass. is there.

  Moreover, the chain transfer agent content in the vinyl monomer composition giving the polymer to be the core phase (A1) is preferably 0 to 10% by mass, more preferably 0 to 1% by mass. As the molecular weight of the core phase (A1) is higher, a coating film having excellent solvent resistance can be obtained from the crosslinkable aqueous coating composition of the present invention comprising the polyisocyanate compound (B) described later. The chain transfer agent content in the vinyl monomer composition in the vinyl monomer system that gives the polymer to be (A1) is preferably substantially zero. Furthermore, a polyfunctional vinyl monomer (for example, divinylbenzene, allyl (meth) acrylate, (poly) oxyethylene di (meth) acrylate) is included in the vinyl monomer composition that gives the polymer to be the core phase (A1). , Trimethylolpropane tri (meth) acrylate, etc.) and a crosslinkable vinyl monomer (for example, the above-mentioned hydrolyzable silyl group-containing vinyl monomer, epoxy group-containing vinyl monomer, etc.) The core phase (A1) has a crosslinked structure, which is preferable for obtaining a coating film having excellent solvent resistance and the like.

  In the above-described polyol component (A) which is a core / shell polymer, the molecular weight distribution dispersion ratio (weight average molecular weight / number average molecular weight) of the shell phase (A2) is 3.5 or more, preferably 4 or more, more preferably 5 When it is above, it is possible to form a coating film having a very excellent coating film appearance (gloss, sharpness, etc.) from the crosslinkable aqueous coating composition of the present invention comprising the polyisocyanate compound (B) described later. Very preferred. Such shell phase (A2) is preferably stepwise or continuous in the above-mentioned encap polymerization, for example, by dividing the chain transfer agent concentration in the vinyl monomer composition in the second stage into two or more stages. It is possible to synthesize it by changing it.

In the aqueous dispersion of the polyol component (A) that is the core / shell polymer described above, the Tg (glass transition temperature) of the shell phase (A2) is 10 ° C. or more, more preferably Tg of the core phase (A1). When the temperature is 20 ° C. or higher, more preferably 30 ° C. or higher, the crosslinkable aqueous coating composition of the present invention is highly compatible with conflicting properties such as contamination resistance and flexibility, and obtains a film with excellent water resistance. Is preferable.
At this time, the Tg of the shell phase (A2) is −10 ° C. <Tg <120 ° C., preferably 0 ° C. <Tg <100 ° C., more preferably 20 ° C. <Tg <70 ° C. The Tg of the core phase (A1) Is −60 ° C. <Tg <30 ° C., preferably −50 ° C. <Tg <0 ° C.

In the present invention, depending on the application, the core / shell polymer may be reversed to the above [the Tg of the core phase (A1) is 10 ° C. or more, more preferably 20 ° C. or more, more preferably 30 ° C. than the Tg of the shell phase (A2). It is also possible to make the design higher.
In the present invention, when carrying out multistage polymerization of three or more stages of chain transfer agent, referring to the synthesis example of the aqueous dispersion of the polyol component (A) by the two-stage polymerization described above, the number of vinyl monomer systems to be polymerized is determined. Increase it. At this time, similarly to the two-stage polymerization, by selecting the hydrophilicity of the vinyl monomer composition used in each vinyl monomer system, it is possible to synthesize various morphologically controlled vinyl polymers.

By the way, the average particle diameter of the aqueous dispersion of the polyol component (A) of the present invention is preferably 10 to 500 nm, more preferably 20 to 300 nm, and still more preferably 40 to 200 nm. The viscosity of the aqueous emulsion is not high at 10 nm or more, and it is also suitable for use at a low non-volatile content concentration. The water resistance of the coating film is good at 500 nm or less.
Moreover, the solid content of the aqueous dispersion of the polyol component (A) is preferably 1 to 60% by mass, more preferably 15 to 55% by mass, and the viscosity at that time is preferably 1 to 100000 mPa · s at 20 ° C. s, preferably 10 to 10,000 mPa · s.

  Further, the aqueous dispersion of the polyol component (A) is preferably adjusted to a pH of 4 to 10 in order to keep it stable for a long time. The pH of the aqueous emulsion can be adjusted preferably by mixing a neutralizing agent at 0 to 100 ° C., preferably 20 to 80 ° C., more preferably 50 to 80 ° C. after completion of the polymerization. Examples of the neutralizing agent include amines such as ammonia, trimethylamine, triethylamine, dimethylethanolamine, methyldiethanolamine, and triethanolamine, inorganic bases such as sodium hydroxide and potassium hydroxide, and hydrochloric acid, sulfuric acid, acetic acid, lactic acid, and the like. Can be mentioned.

Examples of the urethanization reaction catalyst (C) used in the present invention include metal compounds and amine compounds.
Examples of the metal compound include bismuth nitrate, lead 2-ethylhexanoate, lead benzoate, lead oleate, sodium trichlorophenolate, sodium propionate, lithium acetate, potassium oleate, tetrabutyltin, tributyltin chloride, dibutyltin dichloride. , Butyltin trichloride, tin chloride, tributyltin-o-phenolate, tributyltin cyanate, tin octylate, tin oleate, tin tartrate, dibutyltin di (2-ethylhexoate), dibenzyltindi (2-ethylhexoate), Dibutyltin dilaurate, dibutyltin diisooctyl maleate, dibutyltin sulfide, dibutyltin dibutoxide, dibutyltin bis (o-phenylphenolate), dibutyltin bis (acetylacetonate), di (2-ethyl) Ruhexyl) tin oxide, tetra-n-butyl-1,3-diacetyloxydistanoxane, tetra-n-propyl-1,3-diacetyloxydistanoxane, tetra-n-propyl-1-chloro-3-hydroxydisuta Noxan, tetra-n-butyl-1-chloro-3-hydroxydistanoxane, tetramethyl-1,3-diacetyloxydistanoxane, tetramethyl-1-chloro-3-acetyloxydistanoxane, tetra- n-butyl-1,3-diformyloxydistanoxane, tetra-n-butyl-1,3-diacryloxydistanoxane, tetra-n-butyl-1,3-dioleyloxydistanoxane, tetra -n-butyl-1,3-distearyloxydistanoxane, tetra-n-butyl-1,3-diphenylacetyloxydistanoxane, tetra-n-butyl-1,3-diiso Anodistanoxane, tetra-n-butyl-1-acetyloxy-3-hydroxydistanoxane, tetra-n-propyl-1-acetyloxy-3-hydroxydistanoxane, tetramethyl-1-acetyloxy-3 -Hydroxydistanoxane, tetra-n-butyl-1,3-dichlorodistanoxane, tetramethyl-1,3-dichlorodistanoxane, tetra-n-butyl-1,3-dipropoxydistanoxane, tetra -n-propyl-1,3-dipropoxy distanoxane, tetra-n-butyl-1-propoxy-3-acetyloxy distanoxane, tetra-n-propyl-1-hydroxy-3-ethoxy distanoxane, 1,1-dibutyl-3,3-dipropyl-1-hydroxy-3-acetyloxydistanoxane, 1,3-dipropyl-1,3-dibutyl-1-chloro-3-hydroxydistanoxane Titanium tetrachloride, dibutyl titanium dichloride, tetrabutyl titanate, butoxy titanium trichloride, iron trichloride, iron (III) 2-ethylhexanoate, iron (III) acetylacetone, ferrocene, antimony trichloride, antimony pentachloride, trichloride trichloride Phenylantimony, triphenylantimony, uranium nitrate, cadmium nitrate, cadmium diethyldithiophosphate, cobalt benzoate, cobalt 2-ethylhexonate, thorium nitrate, triphenylaluminum, trioctylaluminum, aluminum oleate, diphenylmercury, 2-ethylhexonic acid Zinc, zinc naphthenate, nickelocene, hexacarbonylmolybdenum, cerium nitrate, vanadium trichloride, copper 2-ethylhexonate, copper acetate, manganese 2-ethylhexonate, zirconium 2-ethylhexonate, sodium Ten zirconium, Torifeniruhi arsenide, arsenic trichloride, boron trifluoride - diethyl ether complex, borane, calcium acetate, may be mentioned barium acetate, and the like. These metal catalysts are used alone or as a mixture of two or more.

  The amine compound that can be used as the urethanization reaction catalyst (C) is preferably a tertiary amine. For example, trimethylamine, triethylamine, triisopropylamine, tri-n-propylamine, tri-n-butylamine, triisobutyl. Tertiary alkylamines such as amine and tri-sec-butylamine, aromatic amines such as dimethylaniline, diethylaniline and tribenzylamine, morpholines such as N-methylmorpholine and N-ethylmorpholine, triethanolamine, methyldiethanolamine Alkano such as dimethylethanolamine, diethylethanolamine, dibutylethanolamine, di (2-ethylhexyl) ethanolamine, ethyldiethanolamine, triisopropanolamine, dibutylisopropanolamine Ruamine, tetramethylethylenediamine, tetramethylhexamethylenediamine, tetramethylpropylenediamine, pentamethyldiethylenetriamine, N, N-dimethylcyclohexylamine, N-methylpiperidine, pentamethyldiethylenetriamine, N, N′-endoethylenepiperazine, and N, Diamines and triamines such as N′-dimethylpiperazine and 1,4-diazabicyclo [2,2,2] octane can be used.

As the urethanization reaction catalyst (C) used in the present invention, a metal catalyst is preferable. In particular, organotin compounds such as tin octylate, dibutyltin dilaurate, and distanoxanes have a high catalytic activity for urethanation reaction. Since the distribution to the polyol component (A) to be dispersed is good, it can be preferably used.
The crosslinkable aqueous coating composition of the present invention is characterized by containing the above-described aqueous dispersion of the polyol component (A), the urethanization reaction catalyst (C), and the polyisocyanate compound (B).
In the present invention, the isocyanate group / hydroxyl group equivalent ratio of the polyisocyanate compound (B) and the polyol component (A) is 0.1 to 5.0, preferably 0.5 to 1.5. A cross-linking water-based coating composition having a crosslinking point of 0.1 or more is sufficient, the curing rate is high, and the coating film is difficult to become brittle. A coating thickness of 5.0 or less is preferable because the coating film is not hard and brittle.

Next, the polyisocyanate compound (B) constituting the present invention will be described.
The polyisocyanate compound (B) in the present invention refers to a compound having at least two isocyanate groups in one molecule.
In the present invention, the polyisocyanate compound (B) is added to the polyol component (A) at 0 to 50 ° C., preferably at room temperature, as it is or with a nonionic and / or ionic surfactant, and stirred. Mix to obtain the crosslinkable aqueous coating composition of the present invention.

  Examples of the polyisocyanate compound (B) include 1,4-tetramethylene diisocyanate, ethyl (2,6-diisocyanate) hexanoate, 1,6-hexamethylene diisocyanate, 1,12-dodecamethylene diisocyanate, 2, Aliphatic diisocyanates such as 2,4- or 2,4,4-trimethylhexamethylene diisocyanate; 1,3,6-hexamethylene triisocyanate, 1,8-diisocyanate-4-isocyanate methyloctane, 2 -Aliphatic triisocyanates such as isocyanatoethyl (2,6-diisocyanato) hexanoate; 1,3- or 1,4-bis (isocyanatomethylcyclohexane), 1,3- or 1,4-diisocyanate Cyclohexane, 3,5,5-trimethyl Cycloaliphatic diisocyanates such as 3-isocyanatomethyl) cyclohexyl isocyanate, dicyclohexylmethane-4,4′-diisocyanate, 2,5- or 2,6-diisocyanatomethylnorbornane; 2,5- or 2,6 An alicyclic triisocyanate such as diisocyanate methyl-2-isocyanate propyl norbornane; an aralkylene diisocyanate such as m-xylylene diisocyanate, α, α, α′α′-tetramethyl-m-xylylene diisocyanate; m- or p-phenylene diisocyanate, tolylene-2,4- or 2,6-diisocyanate, diphenylmethane-4,4′-diisocyanate, naphthalene-1,5-diisocyanate, diphenyl-4,4′-diisocyanate, 4,4 '-Gii Aromatic diisocyanates such as isocyanate-3,3′-dimethyldiphenyl, 3-methyl-diphenylmethane-4,4′-diisocyanate, diphenylether-4,4′-diisocyanate; triphenylmethane triisocyanate, tris (isocyanatophenyl) thio Aromatic triisocyanates such as phosphates, and diisocyanates or polyisocyanates having a uretdione structure obtained by cyclizing and dimerizing the above diisocyanates or the isocyanate groups of the triisocyanates; A polyisocyanate having an isocyanurate structure obtained by quantification; the above diisocyanate or triisocyanate is reacted with water; A polyisocyanate having a burette structure obtained by reacting; a polyisocyanate having an oxadiazine trione structure obtained by reacting the diisocyanate or triisocyanate with carbon dioxide; a polyhydroxy compound or a polycarboxy compound having the diisocyanate or triisocyanate; And polyisocyanates obtained by reacting with a compound containing active hydrogen such as a polyamine compound, and the like. These may be used alone or in combination.

  Among the polyisocyanate compounds, aliphatic or alicyclic diisocyanates or triisocyanates, aralkylene diisocyanates, or polyisocyanates derived from them are particularly preferable in terms of weather resistance and pot life. Further, as the polyisocyanate, those having a structure such as burette, isocyanurate, urethane, uretdione, and allophanate in the molecule are preferable. Those having a burette structure are excellent in adhesion, those having an isocyanurate structure are excellent in weather resistance, and those having a urethane structure using an alcohol compound having a long side chain are excellent in elasticity and extensibility. In addition, those having a uretdione structure or an allophanate structure are characterized by low viscosity.

The isocyanate group content of the polyisocyanate compound (B) of the present invention is desirably 8 to 25% by mass. 8% by mass or more is preferable because the crosslinking point in the crosslinkable water-based coating composition is sufficient, the curing rate is high, and the coating such as a coating is difficult to be weakened.
The viscosity of the polyisocyanate compound (B) is preferably 1 to 50000 mPa · s (20 ° C.), more preferably 10 to 20000 mPa · s (20 ° C.). Since it is easy to disperse | distribute to water at 50000 mPa * s or less, it is preferable.
Examples of the nonionic and / or ionic surfactant that can be suitably used for the purpose of improving the water dispersibility of the polyisocyanate compound (B) of the present invention include an emulsifier that can be used for the synthesis of the above-described aqueous emulsion. Can be mentioned.

  As the polyisocyanate compound (B) used in the present invention, from the viewpoint of water dispersibility, a water dispersible polyisocyanate composition (B1) modified with a nonionic and / or ionic surfactant is preferable. It is. The water-dispersible polyisocyanate composition (B1) can be used without particular limitation as long as it has a hydrophilic group introduced by a conventionally known method. For example, an alkoxy polyalkylene glycol and a polyisocyanate compound can be used. A reaction product, a reaction product of a vinyl polymer containing a nonionic group and an isocyanate reactive group (such as a hydroxyl group) and a polyisocyanate compound, an emulsifier obtained by reacting a dialkanolamine, and a polyisocyanate The reaction product of a thio compound and a polyisocyanate compound can be mentioned. Among these, a reaction product of an alkoxy polyalkylene glycol and a polyisocyanate compound is particularly preferable because of its excellent water dispersibility.

  The introduction amount of the hydrophilic group in the water-dispersible polyisocyanate (B1) is preferably 2 to 80% by mass. Since the hydrophilic component is sufficient at 2% by mass or more, the water dispersibility is high and preferable. The reactivity with the polyol component (A) of the water-dispersible polyisocyanate composition is preferably 80% by mass or less because of high reactivity.

The reaction product of the polyisocyanate compound and the alkoxy polyalkylene glycol that can be suitably used as the water-dispersible polyisocyanate (B1) is the polyisocyanate compound (B) and the alkoxy polyalkylene glycol. Is preferably reacted so that the equivalent ratio of isocyanate group / hydroxyl group is 0.5 to 50, preferably about 1 to 25. The alkoxypolyalkylene glycol has the general formula R ¹ O— (R ² O) n —H (where R ¹ is an alkyl group having 1 to 30 carbon atoms, R ² is an alkylene group having 1 to 5 carbon atoms). N is an integer of 5 to 500), for example, polymethylene glycol monomethyl ether, polyethylene glycol monomethyl ether, polyethylene glycol monoethyl ether, polyethylene glycol monopropyl ether, Polyethylene glycol monolauryl ether, polyoxyethylene-oxypropylene (random and / or block) glycol monomethyl ether, polyoxyethylene-oxytetramethylene (random and / or block) glycol polybutylene glycol monomethyl ether, etc. Can. As these alkoxy polyalkylene glycols, those having a molecular weight of preferably 100 to 5,000, more preferably 300 to 2,000 can be suitably used.

The water-dispersible polyisocyanate composition (B1) described above may be mixed with an ionic surfactant that does not substantially contain water. By mixing an ionic surfactant, a double protective film of nonionic hydrophilic group and ionic surfactant is formed on the surface of the polyisocyanate oil droplets, and dispersion stability of the water-dispersible polyisocyanate oil droplets is improved. The property is remarkably improved and water is prevented from entering the polyisocyanate oil droplets. This significantly extends the pot life of the coating composition, reduces the particle size of the polyisocyanate oil droplets, and can further improve the water resistance.
The water dispersion in the present invention refers to a state in which the polyisocyanate compound (B) is dispersed in water so as to be an O / W type, preferably polyisocyanate in water (which may contain a polyol component or the like). It is prepared by adding the compound (B) and mechanically stirring it using a bar or a hand mixer.

The crosslinkable aqueous coating composition used in the present invention can be used by adding an organic solvent that acts as a film forming aid.
The organic solvent functioning as the film-forming aid is a film-forming property of the polyol component (A) that is distributed in the polyol component (A) particles and / or in the aqueous phase in the crosslinkable aqueous coating composition according to the present invention. In addition, the surface of the particles is swollen to promote the crosslinking reaction with the crosslinking agent, and the surface tension of water is lowered to disperse the pigment and to wet the substrate of the crosslinkable aqueous coating composition. As a result, the coating workability and the substrate adhesion can be improved.

  In the present invention, only typical organic solvents that can be suitably used are listed below: 3-methoxybutanol, 3-methoxy-3-methylbutanol, ethylene glycol monoethyl ether, ethylene glycol mono (n- Or i-) propyl ether, ethylene glycol mono (n-, i- or tert-) butyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono (n- or i -) Propyl ether, propylene glycol mono (n-, i- or tert-) butyl ether, mono (di) ethylene glycol dimethyl ether, mono (di) e Renglycol diethyl ether, mono (di) ethylene glycol dibutyl ether, dimethylformamide, N-methylpyrrolidone or ethylene glycol methyl ether acetate and 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate (trade name) CS12 (manufactured by Chisso), diisopropyl glutarate, diisopropyl adipate and the like, and mixtures thereof.

  Among these, aprotic solvents such as mono (di) ethylene glycol dimethyl ether, mono (di) ethylene glycol diethyl ether, mono (di) ethylene glycol dibutyl ether do not react with isocyanate groups and have low odor. It is useful not only as a film-forming aid but also as an antifreeze agent, but also has good affinity for the polyisocyanate compound (B) and enables more uniform crosslinking, so that it is usefully used. be able to.

  When the organic solvent is used, it is used within a range of about 0.1 to 40% by mass, preferably 0.1 to 20% by mass, based on the solid content of the crosslinkable aqueous coating composition of the present invention. preferable. A paint that is less likely to saturate the effect of the organic solvent at 40% by weight or less is preferable because it can reduce flammable flammability, and as a result, there are few restrictions on storage of the paint, coating method, and drying process. The smaller the amount of the organic solvent used, the more desirable in terms of resource saving and environmental pollution countermeasures. The amount of organic solvent in the crosslinkable aqueous coating composition of the present invention is less than 10% by weight. It is preferable from the viewpoint of ignition and combustion prevention, and more preferable is a system that does not substantially contain an organic solvent.

The crosslinkable aqueous coating composition of the present invention exhibits very good film-forming properties even if it does not substantially contain an organic solvent, and reduces or eliminates the organic solvent that has been conventionally used as a film-forming auxiliary. It has the advantage of being able to.
In the crosslinkable water-based coating composition of the present invention, various known and commonly used additives for paints, for example, a thickener, a leveling agent, a thixotropic agent, an antifoaming agent, depending on its use and usage method, etc. Freezing stabilizer, matting agent, crosslinking reaction catalyst, anti-skinning agent, dispersant, wetting agent, light stabilizer, antioxidant, ultraviolet absorber, filler, plasticizer, lubricant, reducing agent, preservative, Additives such as antifungal agents, deodorants, anti-yellowing agents, antistatic agents or charge control agents can be appropriately selected and used as long as they do not interfere with the effects of the present invention. .

  If necessary, the crosslinkable aqueous coating composition of the present invention is imparted with various functions such as coloring, concealment, coating film hardness, drying properties, substrate adhesion, UV blocking and design properties. For this purpose, known and customary pigments can be used. Of these, only typical ones are exemplified. Titanium oxide, calcium carbonate, barium sulfate, mica, silica, talc, clay, petal, iron black, zinc oxide, mapico yellow, carbon black, etc. Various inorganic pigments; or various organic pigments represented by quinacridone red or phthalocyanine blue, and various commercially available aqueous dispersion pigments in which these are dispersed in an aqueous medium. Various types can be used.

The amount of the pigment used is not particularly limited, but is about 300 parts by mass or less, preferably 200 parts by mass or less, and more preferably 150 parts by mass with respect to 100 parts by mass of the solid content of the crosslinkable aqueous coating composition of the present invention. Use within the range of less than or equal to part is particularly preferable from the viewpoint of durability of the obtained coating film.
The crosslinkable aqueous coating composition of the present invention is prepared by, for example, dispersing a polyol component (A) and a pigment in advance to prepare a pigment paste in advance, and then adding the remaining polyol component (A) and, if necessary, an additive The paint can be prepared by adding and letting down. This method is the same as a conventional method for producing a so-called solvent-based paint, and is very desirable for improving the productivity of the paint and various performances of the obtained coating film. In that case, it does not prevent the use of other additives necessary for the preparation of the pigment paste.

The crosslinkable aqueous coating composition of the present invention is preferably used as a two-component paint, and uses an aqueous dispersion of a polyol component (A) containing a urethanization reaction catalyst (C) and a polyisocyanate compound (B). It is preferable to mix it immediately before use.
Moreover, the crosslinkable aqueous coating composition of the present invention is preferably within 24 hours after mixing the aqueous dispersion of the polyol component (A) containing the urethanization reaction catalyst (C) and the polyisocyanate compound (B). By using it preferably within 12 hours, more preferably within 8 hours, and most preferably within 4 hours, it becomes possible to produce a coating film having very excellent physical properties.

The crosslinkable water-based coating composition of the present invention is not particularly limited in use and base material, and in addition, various known and conventional methods such as a coating method and a drying method can be used depending on the purpose. It can be selected and used as appropriate. Moreover, although there is no restriction | limiting also about a coating film thickness, in order to express the outstanding coating-film physical property, it is desirable to coat so that it may become in the range of 1-300 micrometers, Preferably 5-150 micrometers.
The crosslinkable aqueous coating composition of the present invention may be applied directly to the base material, but for the purpose of improving the adhesion to the base material, it may also be applied to a base material treated with a sealer as a base conditioner. Is possible.

  As the sealer, all sealers such as a water-based sealer, an organic solvent-based sealer, and a solvent-free sealer can be used, but it is preferable to use a water-based sealer in view of the environment. Examples of the water-based sealer include an acrylic resin system, a chlorinated polyolefin system, and a reaction curing system. These water-based sealers may be either emulsion-based or water-soluble resin-based, and may be any of anionic, cationic or nonionic. When the crosslinkable aqueous coating composition of the present invention is anionic, the use of a cationic sealer is preferable in terms of adhesion and the like.

  When the crosslinkable aqueous coating composition of the present invention is applied to various substrates, any coating method can be applied as described above. Of these coating methods, only typical ones are illustrated. All general-purpose coating methods such as spray, brush, roller, curtain coater, dip coating method, roll coater, and gravure coater can be used. It can be selected in consideration of sex. The drying method can be forced drying in addition to room temperature drying.

  The crosslinkable water-based coating composition of the present invention thus obtained includes paints, building material base treatment materials or finishing materials, adhesives, pressure-sensitive adhesives, paper processing agents or woven fabrics, non-woven fabric finishing materials, as well as sealing agents and adhesives. , Ink, coating material, casting material, elastomer, foam and plastic raw material, fiber treatment agent, etc. can be used widely.

  Examples of the above-mentioned paints, building material base treatment materials or finishing materials include, for example, concrete, cement mortar, slate plates, calcium plates, gypsum boards, extruded plates, foamed concrete, and other inorganic building materials, woven fabrics or non-woven fabrics. Paints and building finishes for various bases such as finished building materials and metal building materials, as well as main materials and top coats for multi-layer finish coating materials, thin finish coating materials, thick finish finish coating materials, stone finish finish materials, gloss paint Synthetic resin emulsion paints, metal paints, wood paints, tile paints, automobiles, aircraft, ships, new plastics (on-site painting, factory line painting), or repair paints. .

Examples of adhesives include wet adhesives and contact adhesives for metals, plastics, wood, slate, paper, cloth, etc., which are used as adhesives for automobile interiors, adhesives for building members, laminate adhesives for various films, etc. Agents and the like.
Examples of the pressure-sensitive adhesive include permanent pressure-sensitive adhesives and re-peelable pressure-sensitive adhesives used for single-sided tapes, double-sided tapes, labels, albums, and the like.

The following examples, reference examples and comparative examples will specifically explain the present invention, but these do not limit the scope of the present invention. In Examples, Reference Examples and Comparative Examples, various physical properties were measured by the following methods.
1. Particle size distribution and number average particle size A solvent was appropriately added to dilute the photocatalyst content in the sample to 1 to 20% by mass, and measurement was performed using a wet particle size analyzer (Nikkiso Microtrac UPA-9230).

2. Number average molecular weight, molecular weight distribution dispersion ratio (weight average molecular weight / number average molecular weight)
It calculated | required by the gel permeation chromatography (GPC) using the analytical curve created using the polystyrene sample.
The conditions for GPC are as follows.
Apparatus: Tosoh HLC-8020 LC-3A type chromatograph column: TSKgel G1000H _XL , TSKgel G2000H _XL, and TSKgel G4000H _XL (all manufactured by Tosoh) were used in series.
Data processor: CR-4A type data processor manufactured by Shimadzu Corporation Mobile phase: Dimethylacetamide Flow rate: 1.0 ml / min.
-Sample preparation method It melt | dissolved with the solvent used for a mobile phase (concentration was suitably adjusted in the range of 0.1-1 mass%), and used for the analysis.

3. Viscosity Using a Brookfield viscometer, rotor No. 2. Measurement was performed under the conditions of 60 rpm and 20 ° C.
4). Quantification of dibutyltin dilaurate (urethanization reaction catalyst) distributed to polyol component (A) After repeating the centrifugation and washing the aqueous dispersion of polyol component (A) containing dibutyltin dilaurate prepared in each reference example three times, The polyol (A) phase was dried at 120 ° C. for 2 hours. The obtained sample was incinerated in an electric furnace at 500 ° C., then potassium carbonate / sodium was added and melted, dissolved in an aqueous hydrochloric acid solution, and then an inductively coupled plasma emission spectrometer (ICP-AES). Was determined by quantitatively determining tin. Further, the amount of dibutyltin dilaurate in the aqueous phase was quantified by analyzing tin in the aqueous phase separated by the first centrifugation by ICP-AES.

5. Isocyanate group content After neutralizing the isocyanate group with excess dibutylamine, it was determined by back titration with hydrochloric acid.
6). Initial gel fraction The composition of each example and comparative example was applied on a PP plate at a film thickness setting of 100 μm and left in a constant temperature and humidity chamber (23 ° C., humidity 60%) for 24 hours to form a coating film. Created. After peeling off the coating film prepared from the PP plate, about 0.1 g of the coating film was weighed and placed in a wire mesh (200 mesh) bag and immersed in 50 g of acetone at room temperature for 24 hours. The retention was calculated according to the following formula:
Gel fraction = coating mass after immersion in acetone / coating mass before immersion in acetone × 100%

7). Initial water resistance The composition of each example and comparative example was applied to a glass plate with a film thickness of 100 μm, and left in a constant temperature and humidity chamber (23 ° C., humidity 60%) for 24 hours to form a coating film. did. About 1 g of purified water was placed on the obtained coating film as a water droplet having a diameter of about 3 cm, covered with a watch glass and allowed to stand at room temperature for 24 hours, and then the state of the coating film was observed and evaluated.
A: No change
○: Slightly whitened
Δ: Whitening
×: Severe whitening

8). Hardness On the glass plate with a thickness of 2 mm, the compositions of the examples and comparative examples were applied at a film thickness of 50 μm, and left in a constant temperature and humidity chamber (23 ° C., humidity 60%) for 24 hours. It was created. The hardness of the obtained glass plate with a coating film was measured as Koenig hardness with a pendulum hardness tester (Pendulum hardness tester manufactured by BYK Chemie) in a thermostatic chamber at 23 ° C.
9. Flexibility On the tin plate with a thickness of 0.1 mm, the formulations of the examples and comparative examples were applied at a film thickness setting of 20 μm and left for 24 hours in a constant temperature and humidity chamber (23 ° C., humidity 60%). Then, a coating film was prepared, and a 2φ / 180 ° bending test was performed in a thermostatic chamber at 23 ° C., and the presence or absence of abnormality was visually evaluated.
○: No abnormality in cracking or peeling, Δ: slight peeling, ×: cracking or peeling

10. Enamel Gloss After adjusting the enamel paint (main agent) by the method shown below, blending and stirring a predetermined amount of polyisocyanate compound, it is applied on a 2 mm thick glass plate with a film thickness of 50 μm and kept constant. An enamel film was prepared by leaving it in a damp chamber (20 ° C, 60% humidity) for 1 week, and a value of 60 ° -60 ° was measured using a digital variable angle gloss meter manufactured by Suga Test Instruments Co., Ltd. did.
<Adjustment of enamel coating composition>
・ Preparation of pigment dispersion Water 147.5g
Dispersant: Pig. Disperser MD20 5.4g
(Product name, manufactured by BASF Japan)
Concentrated aqueous ammonia 0.5g
Propylene glycol 23.5g
Typep CR-97 (product name, manufactured by Ishihara Sangyo Co., Ltd.) 333.5 g
Antifoaming agent: SN deformer 1310 2.9 g
(Product name, manufactured by San Nopco)
The above blend was dispersed for 20 minutes in a tabletop sand mill to obtain a pigment dispersion.
-Production of enamel paint Coating composition of each example and comparative example (in terms of solid content) 50.0 g
10.0 g of water
51.3 g of the above pigment dispersion
Thickener: 10% by weight aqueous solution of Adecanol UH-438
(Product name, manufactured by Asahi Denka Kogyo Co., Ltd.)

11. Storage Stability The formulations of each Example and Comparative Example were evaluated by observing the state when left at 23 ° C. for 4 hours.

A: No change
Δ: thickening
×: Gelation

Reference Example 1 Synthesis of Polyol Component Water Dispersion (D1) In a 2 L reactor having a reflux condenser, a dropping tank, a thermometer, and a stirrer, 446.8 g of ion-exchanged water, a surfactant (trade name: ADEKA) 14.5 g of 25% aqueous solution of Rear Soap SE-1025N, manufactured by Asahi Denka Kogyo Co., Ltd. is added, the temperature in the reaction vessel is raised to 80 ° C., and 4.2 g of 2% aqueous solution of ammonium persulfate is then added. Stir for minutes. Next, 11% of 25% aqueous solution of 3.8 g of acrylic acid, 125.6 g of butyl acrylate, 112.3 g of butyl methacrylate, 9.5 g of 2-hydroxyethyl methacrylate, 218.0 g of ion-exchanged water, and Adecare Soap SE-1025N 0.7 g, a mixed solution of 6.5 g of 25% aqueous solution of polyoxyethylene nonylphenyl ether (trade name: Emulgen 950, manufactured by Kao Corp.) and 25.1 g of 2% aqueous solution of ammonium persulfate into a reaction vessel, 2 It was allowed to flow in over time. During the inflow, the temperature in the reaction vessel was kept at 80 ° C. After completion of the inflow, the temperature in the reaction vessel was raised to 80 ° C. and kept for 1 hour. At this time, the number average particle diameter of the produced aqueous dispersion (core phase) was 48 nm.

  Next, 14.7 g of acrylic acid, 86.4 g of butyl acrylate, 40.3 g of butyl methacrylate, 335.0 g of methyl methacrylate, 110.9 g of 2-hydroxyethyl methacrylate, 1.8 g of lauryl mercaptan, 518.0 g of ion-exchanged water A mixture of 17.35 g of Adekalya soap SR-1025, 25% aqueous solution of Emulgen 950, 8.8 g of 25% aqueous solution of Emulgen 950, and 58.6 g of 2% aqueous solution of ammonium persulfate flows into the reaction vessel over 3 hours. I let you. During the inflow, the temperature in the reaction vessel was kept at 80 ° C. After completion of the inflow, the temperature in the reaction vessel was raised to 80 ° C. and kept for 1 hour. Thereafter, 5.3 g of a 5% aqueous ammonia solution was added, and the temperature in the reaction vessel was kept at 80 ° C. for 1.0 hour. Thereafter, the mixture was cooled to room temperature and filtered through a 100-mesh wire mesh to obtain an aqueous dispersion (D1) of a polyol component (A1) having a solid content of 38% and a viscosity of 11000 mPa · s.

The obtained aqueous dispersion (D1) of the polyol component is monodispersed (number average particle size is 102 nm) and is derived from the core phase (number average particle size is 48 nm) obtained by the first stage polymerization. Had disappeared. The number average molecular weight of the shell phase polymerized in the second stage was 47000, and the molecular weight distribution dispersion ratio (weight average molecular weight / number average molecular weight) was 4.3.
The number average molecular weight of the polyol component (A1) in the synthesized water dispersion (D1) was 53000, and the molecular weight distribution dispersion ratio (weight average molecular weight / number average molecular weight) was 8.1.
Furthermore, the hydroxyl value obtained from the calculation of the synthesized polyol component (A1) is 60.5 mgKOH / g, the acid value derived from the carboxyl group is 16.7 mgKOH / g, the glass transition temperature of the core phase is −20 ° C., the shell phase The glass transition temperature is 55 ° C., and the average glass transition temperature is 28 ° C.

[Reference Example 2] Preparation of aqueous dispersion (D2) of polyol component containing urethanization reaction catalyst To 1000 g of aqueous dispersion (D1) of polyol component (A1) synthesized in Reference Example 1, 0.15 g of dibutyltin dilaurate ( About 400 ppm) was added at room temperature with stirring, and stirring was continued for 24 hours to prepare an aqueous dispersion (D2) of a polyol component containing dibutyltin dilaurate (urethanization reaction catalyst).
Tin was not detected in the aqueous phase in the prepared aqueous dispersion (D2), and 390 ppm of tin was detected in the polyol component (A1) phase in terms of dibutyltin dilaurate.

[Reference Example 3] Synthesis of water dispersion (D3) of polyol component containing urethanization reaction catalyst In a 2 L reactor having a reflux condenser, a dropping tank, a thermometer and a stirrer, 446.8 g of ion-exchanged water, interface 14.5 g of a 25% aqueous solution of an activator (trade name: Adeka Soap SE-1025N, manufactured by Asahi Denka Kogyo Co., Ltd.) was added, the temperature in the reaction vessel was raised to 80 ° C., and 2% of ammonium persulfate 4.2 g of an aqueous solution was added and stirred for 5 minutes.

  Next, 18.5 g of acrylic acid, 212.0 g of butyl acrylate, 152.3 g of butyl methacrylate, 335.0 g of methyl methacrylate, 120.4 g of 2-hydroxyethyl methacrylate, 2.5 g of lauryl mercaptan, 0.84 g of dibutyltin dilaurate ( Approx. 1000 ppm), 736.0 g of ion-exchanged water, 29.0 g of 25% aqueous solution of Adeka Soap SE-1025N, 25% aqueous solution 15 of polyoxyethylene nonylphenyl ether (trade name: Emulgen 950, manufactured by Kao Corporation) 15 .3 g and a mixed solution of 83.6 g of 2% aqueous solution of ammonium persulfate were allowed to flow into the reaction vessel from the dropping tank over 3 hours. During the inflow, the temperature in the reaction vessel was kept at 80 ° C. After completion of the inflow, the temperature in the reaction vessel was raised to 80 ° C. and kept for 1 hour. Thereafter, 5.3 g of a 5% aqueous ammonia solution was added, and the temperature in the reaction vessel was maintained at 80 ° C. for 1 hour. Thereafter, the mixture is cooled to room temperature, filtered through a 100-mesh wire mesh, and water dispersion of a polyol component (A3) containing dibutyltin dilaurate (urethanization reaction catalyst) having a solid content of 38%, a viscosity of 12,000 mPa · s, and a number average particle size of 102 nm. A body (D3) was obtained.

The number average molecular weight of the polyol component (A3) in the synthesized water dispersion (D3) was 43,000, and the molecular weight distribution dispersion ratio (weight average molecular weight / number average molecular weight) was 3.4.
Furthermore, the hydroxyl value obtained from the calculation of the synthesized polyol component (A3) is 60.5 mgKOH / g, the acid value derived from the carboxyl group is 16.7 mgKOH / g, and the glass transition temperature is 28 ° C.
Tin was not detected in the aqueous phase in the synthesized aqueous dispersion (D3), and 960 ppm of tin was detected in the polyol component (A3) phase in terms of dibutyltin dilaurate.

[Reference Example 4] Synthesis of aqueous dispersion of polyol component (D4) The same operation as in Reference Example 3 was performed except that 0.84 g of dibutyltin dilaurate was not used. The solid content was 38%, the viscosity was 16000 mPa · s, and the number average particle size was An aqueous dispersion (D4) of a 112 nm polyol component (A3) was obtained.
The number average molecular weight of the polyol component (A4) in the synthesized aqueous dispersion (D4) was 33,000, and the molecular weight distribution dispersion ratio (weight average molecular weight / number average molecular weight) was 3.1.

[Reference Example 5] Preparation of aqueous dispersion (D5) of polyol component containing urethanization reaction catalyst To 1000 g of aqueous dispersion (D4) of polyol component (A4) synthesized in Reference Example 4, 4.1 g of dibutyltin dilaurate ( About 11000 ppm) was added at room temperature with stirring, and stirring was continued for 24 hours to prepare an aqueous dispersion (D5) of a polyol component containing dibutyltin dilaurate (urethanization reaction catalyst).
Tin was detected in the aqueous phase in the prepared aqueous dispersion (D5) (measurement variation was large and quantification was impossible).

[Reference Example 6] Synthesis of polyisocyanate compound (B1) Methoxypolyethylene glycol (MPG-081, ethylene oxide repeating unit = 15.0, manufactured by Nippon Emulsifier Co., Ltd.) and sodium dialkylsulfosuccinate (Newcol 290M, solid content 70) %, Manufactured by Nippon Emulsifier Co., Ltd.) in a weight ratio of 2: 1, and water and solvent were removed by distillation under reduced pressure. 1000 g of burette type polyisocyanate (Duranate 24A-100, manufactured by Asahi Kasei Kogyo Co., Ltd.) and 300 g of a mixture of methoxypolyethylene glycol and sodium dialkylsulfosuccinate obtained above were mixed and subjected to urethanization reaction at 90 ° C. for 2 hours. The obtained water-dispersible polyisocyanate composition {polyisocyanate compound (B1)} was a pale yellow liquid, had an isocyanate group content of 16.6% and a viscosity of 4100 mPa · s.

[Example 1]
23.4 g of the polyisocyanate compound (B1) synthesized in Reference Example 6 was added to 200 g of the aqueous dispersion (D2) of the polyol component containing the urethanization reaction catalyst synthesized in Reference Example 2 (NCO / OH equivalent ratio = 1). 25), and stirred at 600 rpm for 10 minutes to obtain a crosslinkable aqueous coating composition (E1).
The initial gel fraction of the coating film prepared from the resulting crosslinkable aqueous coating composition (E1) is 93%, the initial water resistance is good (、), the hardness (Konig hardness) is 57 times, and the flex resistance is ○. Furthermore, the storage stability was very good (◎).
The enamel gloss was a very high value of 85%.

[Example 2]
23.4 g of the polyisocyanate compound (B1) synthesized in Reference Example 6 was added to 200 g of the aqueous dispersion (D3) of the polyol component containing the urethanization reaction catalyst synthesized in Reference Example 3 (NCO / OH equivalent ratio = 1). 25), and stirred at 600 rpm for 10 minutes to obtain a crosslinkable aqueous coating composition (E2).
The initial gel fraction of the coating film prepared from the resulting crosslinkable aqueous coating composition (E2) was 92%, the initial water resistance was good (、), the hardness (Konig hardness) was 37 times, and the flex resistance was Δ. Furthermore, the storage stability was very good (◎).
The enamel gloss was a very high value of 84%.

[Comparative Example 1]
23.4 g of the polyisocyanate compound (B1) synthesized in Reference Example 6 (NCO / OH equivalent ratio = 1.25) was added to 200 g of the aqueous dispersion (D1) of the polyol component synthesized in Reference Example 1 and 10 at 600 rpm. The mixture was stirred for a minute to obtain a crosslinkable aqueous coating composition (E3).
The initial gel fraction of the coating film prepared from the obtained crosslinkable aqueous coating composition (E3) is as low as 82%, the initial water resistance is poor (Δ), and the hardness (Konig hardness) is very high at 7 times. It was soft. However, the storage stability was very good (◎).

[Comparative Example 2]
23.4 g of the polyisocyanate compound (B1) synthesized in Reference Example 6 (NCO / OH equivalent ratio = 1.25) is added to 200 g of the aqueous dispersion (D4) of the polyol component synthesized in Reference Example 4, and 10 at 600 rpm. The mixture was stirred for a minute to obtain a crosslinkable aqueous coating composition (E4).
The initial gel fraction of the coating film prepared from the obtained crosslinkable aqueous coating composition (E4) is as low as 62%, the initial water resistance is very poor (x), and the hardness (Konig hardness) is 4 times. It was very soft. However, the storage stability was very good (◎).

[Comparative Example 3]
Dibutyltin dilaurate 0.03 g (corresponding to about 400 ppm) was added to 200 g of the polyol component aqueous dispersion (D4) synthesized in Reference Example 4, and then 23.4 g of the polyisocyanate compound (B1) synthesized in Reference Example 6 was added. (NCO / OH equivalent ratio = 1.25) and stirred at 600 rpm for 10 minutes to obtain a crosslinkable aqueous coating composition (E5).
The initial gel fraction of the coating film prepared from the obtained crosslinkable aqueous coating composition (E5) is as low as 74%, the initial water resistance is very poor (x), and the hardness (Konig hardness) is 8 times. It was very soft. Further, the storage stability was poor (Δ).

[Comparative Example 4]
23.4 g of the polyisocyanate compound (B1) synthesized in Reference Example 6 (NCO / OH equivalent ratio = 1.25) was added to 200 g of the aqueous dispersion (D5) of the polyol component synthesized in Reference Example 5 and 10 at 600 rpm. The mixture was stirred for a minute to obtain a crosslinkable aqueous coating composition (E6).
The initial gel fraction of the coating film prepared from the resulting crosslinkable aqueous coating composition (E6) is 95%, the initial water resistance is very good (◎), and the hardness (Konig hardness) is 48 times. there were. However, the storage stability was very poor (×).

  The crosslinkable aqueous coating composition of the present invention is mainly composed of architectural water-based paints, automotive water-based paints, adhesives, building materials, household water-based paints, other coating agents, sealing agents, inks, casting materials, elastomers, foams, and plastic raw materials. It can be used as a fiber treatment agent.

Claims (5)

It comprises an aqueous dispersion of a polyol component (A) having a hydroxyl value of 10 to 200 mgKOH / g, a polyisocyanate compound (B), and a urethanization reaction catalyst (C), and [isocyanate group of polyisocyanate compound (B)] / The equivalent ratio of [hydroxyl group of the polyol component (A)] is 0.1 to 5.0, and the urethanization reaction catalyst (C) is dispersed in water in the polyol component (A). A crosslinkable aqueous coating composition characterized in that it is present in an amount of 5 to 10,000 ppm relative to the mass of A). The crosslinkable aqueous coating composition according to claim 1, wherein the polyisocyanate compound (B) is a water-dispersible polyisocyanate composition (B1). 3. The polystyrene-converted molecular weight distribution dispersion ratio (weight average molecular weight / number average molecular weight) of the polyol component (A) measured by gel permeation chromatography is 3.5 or more. A crosslinkable aqueous coating composition as described in 1. above. The polyol component (A) is a core phase (A1) having a polystyrene-equivalent number average molecular weight of 100,000 or more measured by gel permeation chromatography and a polystyrene-equivalent number average molecular weight measured by gel permeation chromatography. A core / shell polymer comprising a shell phase (A2) of 3000 to 100,000, wherein the mass ratio is (A2) / (A1) = 9/1 to 1/9. 4. The crosslinkable aqueous coating composition according to any one of 3 above. The crosslinkable aqueous coating composition according to any one of claims 1 to 4, wherein the urethanization catalyst (C) is an organotin compound.