JP4099142B2 - Two-component curable aqueous coating composition and method for producing aqueous emulsion - Google Patents

Description

  The present invention relates to a two-component curable aqueous coating composition containing a tertiary amino group-containing urethane prepolymer and excellent in crack resistance and flex resistance. The present invention also includes a step of mixing a tertiary amino group-containing urethane prepolymer, an aqueous emulsion constituting the first liquid of the two-part curable aqueous coating composition, and a two-part curable comprising such an aqueous emulsion. The present invention relates to a method for producing a water-based paint composition of a mold.

  Conventionally, organopolysiloxane-based paints have been used as paint compositions having excellent weather resistance and stain resistance. These performances of the organopolysiloxane-based paint are attributable to siloxane bonds formed three-dimensionally, but on the other hand, there are problems of brittleness of the coating film and poor adhesion to the substrate. In order to improve these performances, attempts have been made to introduce organic resins such as alkyd resins, polyester resins, acrylic resins, and epoxy resins into the paint.

  For example, in Patent Document 1, (i) solution polymerization of a carboxyl group-containing resin, (ii) neutralization and self-emulsification, (iii) introduction of a tertiary amino group by seed polymerization, (iv) 3 A two-component aqueous resin composition containing an aqueous resin complexed with polysiloxane, produced by each step of conducting an organosiloxane hydrolytic condensation reaction in an emulsion of a secondary amino group-containing polymer has been proposed. . And it is disclosed that this two-component coating composition has good storage stability, and an excellent coating film such as water resistance and alkali resistance can be obtained.

  Patent Document 2 discloses (i) solution polymerization of an acrylic resin, (ii) mixing with an organosilane compound, hydrolytic condensation reaction, (iii) self-emulsification after neutralization, (iv) A two-component aqueous resin composition containing an organic-inorganic composite resin aqueous emulsion produced by each step of converting an amino group-containing alkoxysilane compound has been proposed. And it is disclosed that the coating film obtained by this two-component coating composition has excellent hot water resistance, weather resistance and the like.

JP-A-11-116683 Japanese Patent No. 3457232

  However, it has been found that conventional organopolysiloxane-based paints do not have sufficient crack resistance and flex resistance when formed into a coating film. In particular, in the field of construction and civil engineering structures, there are many highly flexible members, and there is a strong demand for inorganic, low-pollution, highly weather-resistant paints having excellent flex resistance and crack resistance. In recent years, it has also been required for detached houses to maintain long-term coating performance such as 10 years or 20 years mainly for ceramics and metal siding materials.

  Therefore, in order to improve the bending resistance and crack resistance of the resulting coating film, studies have been made to increase the amount of organic resin introduced into the organopolysiloxane-based paint. By increasing the amount of organic resin, it is possible to improve the flex / crack resistance of the coating film, but on the other hand, the weather resistance and contamination resistance characteristic of organopolysiloxane paints deteriorate. I understood that.

  Thus, in conventional organopolysiloxane paints, weather resistance / contamination resistance and flexibility / crack resistance are not achieved at the same time, and the original weather resistance performance of the organopolysiloxane paint is impaired. There is also a demand for an organopolysiloxane-based coating composition having excellent flex resistance and crack resistance.

On the other hand, in recent years, water-based paints have been strongly demanded from the viewpoint of ensuring the safety of the global environment and work environment (water-based paints can also be used for living rooms).
Therefore, on the premise that the organic solvent is a water-based paint (water-based paint; emulsion-based paint) with a significantly reduced amount of organic solvent, and as described above, in addition to the original weather resistance performance of the organopolysiloxane paint, it is also resistant to bending and resistance. There is a demand for an organopolysiloxane coating composition that balances various performances such as excellent cracking properties.

  The present invention has been made on the basis of such a demand, and its object is to provide a two-component room temperature curing organopolysiloxane-based water-based paint having excellent bending resistance and crack resistance in addition to weather resistance. It is to provide a composition. A further object of the present invention is to provide a method for producing an aqueous emulsion constituting one liquid of a two-pack room temperature curing organopolysiloxane-based aqueous coating composition. Furthermore, another object of the present invention is to provide a method for producing an aqueous coating composition containing such an aqueous emulsion.

That is, in order to solve the above problems, according to the present invention, a first liquid composed of an aqueous emulsion containing a carboxyl group-containing acrylic copolymer, an organosiloxane and a tertiary amino group-containing urethane prepolymer, and an epoxy group A two-component curable aqueous coating composition comprising a second solution containing an organic silane compound is provided. Here, the tertiary amino group-containing urethane prepolymer passes through the epoxy group-containing organic silane compound as the crosslinking agent or the epoxy group-containing organic silane compound as the crosslinking agent and the organosiloxane when the aqueous coating composition is cured. Thus, it becomes a part of cross-linking between molecules of the carboxyl group-containing acrylic copolymer.
The “crosslinking agent” is contained in the second liquid and plays a role of promoting cross-linking of each component contained in the first liquid when the aqueous coating composition is cured (for example, the first liquid is here). This refers to an epoxy group-containing organosilane compound that promotes crosslinking of each component of the carboxyl group-containing acrylic copolymer, organosiloxane, and tertiary amino group-containing urethane prepolymer contained in the liquid).

  According to the present invention, there is also provided an aqueous emulsion production method comprising one liquid of a two-part curable aqueous coating composition, comprising: (i) a carboxyl group having an acid value of 20 to 100 mgKOH / a step of producing an acrylic copolymer (a) which is g, and (ii) a mixture of 20 to 200 parts by weight of the acrylic copolymer (a) and 100 parts by weight of an alkoxy group-containing organosilane compound (b). A step of hydrolytic condensation in the presence of 0.1 to 30 parts by weight of water and an organometallic compound (c), (iii) a tertiary amino group in at least one molecule in the product from the step (ii) A step of mixing 5 to 50 parts by weight of a urethane prepolymer (d) having an amine value of 10 to 350 mgKOH / g, (iv) a neutralizing agent and water in the mixture from the step (iii) Add And the sum, the step of self-emulsifying, including the aqueous emulsion manufacturing method is provided.

  Furthermore, according to the present invention, there is provided a method for producing a two-part curable aqueous coating composition, wherein the aqueous emulsion constituting one part of the composition has (i) a carboxyl group, A step of producing an acrylic copolymer (a) having a value of 20 to 100 mg KOH / g, (ii) 20 to 200 parts by weight of the acrylic copolymer (a) and an alkoxy group-containing organosilane compound (b) 100 (Iii) a step of hydrolytic condensation in the presence of 0.1 to 30 parts by weight of water and the organometallic compound (c) with respect to the mixture of parts by weight; (iii) a tertiary amino A step of mixing 5 to 50 parts by weight of a urethane prepolymer (d) having at least two groups in one molecule and an amine value of 10 to 350 mgKOH / g, (iv) a mixture from the above step (iii) Inside Two-component curable aqueous solution, comprising adding an agent and water to neutralize and self-emulsifying, and including the other one solution containing an epoxy group-containing organosilane compound as a crosslinking agent A method for producing a coating composition is provided.

As described above, the two-component curable aqueous coating composition of the present invention includes a first solution composed of an aqueous emulsion containing a carboxyl group-containing acrylic copolymer and an organosiloxane, and an epoxy group-containing organic as a crosslinking agent. It consists of the 2nd liquid containing a silane compound. Below, an acrylic copolymer (a), an alkoxy group-containing organosilane compound (b), an organometallic compound (c) and a urethane prepolymer (d), which are components for producing the first liquid, Each component of the epoxy group-containing organic silane compound as a crosslinking agent constituting the second liquid and a compound having at least two epoxy groups in one molecule as an optional crosslinking agent will be described in detail.
In addition, "organosiloxane" said here is a product obtained by processing the alkoxy group-containing organosilane compound (b) in the hydrolysis condensation step described in detail later. Further, here, “first” and “second” are referred to as such for convenience in order to deal with each of the two liquids in the specification, and have special meanings for the numbers themselves. There is no reason. The two-component curable aqueous coating composition of the present invention is prepared by mixing two components consisting of a first solution and a second solution at the time of use.

<(A) component>
The carboxyl group-containing acrylic copolymer used as the component (a) has an acid value of 20 to 100 mgKOH / g, more preferably from the viewpoint of the amount of crosslinking with the epoxy group in the second liquid and the storage stability of the aqueous emulsion. An acrylic copolymer of 30 to 70 mg KOH / g is used. Moreover, in addition to having a carboxyl group and an acid value of 20 to 100 mgKOH / g, it further has a tertiary amino group, and an amine value of greater than 0 mgKOH / g and less than or equal to 50 mgKOH / g. More preferably, an acrylic copolymer having an amine value of 50% or less of the acid value (the tertiary amino group is 0.5 mol or less relative to 1 mol of the carboxyl group) may be used.

  In addition, the acrylic copolymer used as the component (a) preferably has a number average molecular weight (in terms of standard polystyrene) of 3,000 to 100,000, more preferably 5,000 to 50,000.

  The monomer composition constituting the component (a) is not particularly limited as long as it has a carboxyl group and optionally a tertiary amino group, but the monomer having a Tg of -30 to 30 ° C in the component (a) A composition is preferred. The component (a) having a Tg in the range of −30 to 30 ° C. includes, for example, an ethylenically unsaturated monomer (a1) and a carboxyl group and optionally a tertiary amino group copolymerizable with the monomer (a1). It can be obtained by copolymerizing the ethylenically unsaturated monomer (a2) in a solvent using a radical polymerization initiator.

  Here, as the ethylenically unsaturated monomer (a1), methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl ( C1-C24 alkyl of (meth) acrylic acid such as (meth) acrylate, n-hexyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate or the like Examples thereof include cycloalkyl esters, styrene, vinyl toluene, α-methyl styrene, alkylene glycol di (meth) acrylates such as ethylene glycol di (meth) acrylate, and vinyl acetate. The monomers (a1) described above can be used in combination of two or more.

  Moreover, it is also possible to use a hydroxyl-containing ethylenically unsaturated monomer as the ethylenically unsaturated monomer (a1). Specifically, polyoxyalkylene glycol (meth) acrylates such as 2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, 4-hydroxybutyl acrylate, and diethylene glycol (meth) acrylate (the number of carbon atoms of the alkylene group is 2). -4, and the number of added moles of alkylene oxide is 1-50.), Caprolactone-modified hydroxy (meth) acrylate, N-methylolacrylamide and the like.

  Specific examples of the ethylenically unsaturated monomer (a2) containing a carboxyl group and optionally a tertiary amino group that can be copolymerized with the ethylenically unsaturated monomer (a1) include (meth) acrylic acid, itaconic acid, maleic acid. , Carboxyl group-containing ethylenically unsaturated monomers such as fumaric acid and crutonic acid, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, di-n-propylaminoethyl (meth) acrylate, 3-dimethylaminopropyl Tertiary amino group-containing (meth) acrylates such as (meth) acrylate and 4-dimethylaminobutyl (meth) acrylate, tertiary amino group-containing aromatic unsaturated monomers such as vinylpyridine, N- (2-dimethylamino) ethyl (Meth) acrylamide, N- (2-diethylamino) ethyl (me ) Acrylamide, N- (2-di-n-propylamino) ethyl (meth) acrylamide, N- (3-dimethylamino) propyl (meth) acrylamide, N- (4-dimethylamino) butyl (meth) acrylamide, etc. Tertiary amino group-containing (meth) acrylamides, tertiary amino group-containing vinyl ethers such as dimethylaminoethyl vinyl ether, diethylaminoethyl vinyl ether, 3-dimethylaminopropyl vinyl ether, 4-dimethylaminobutyl vinyl ether, and the like. These monomers can also be used in combination of two or more.

  The solvent used for the polymerization is not particularly limited as long as it can be solution-polymerized and can dissolve the monomer to be used and the polymer to be obtained. Specifically, alcohol solvents such as methanol, ethanol and isopropanol, ester solvents such as ethyl acetate and butyl acetate, ketone solvents such as acetone and methyl ethyl ketone, alcohol ether solvents such as ethylene glycol monoethyl ether and ethylene glycol monobutyl ether And aromatic solvents such as toluene and xylene, polar solvents such as N-methylpyrrolidone, dimethylformamide, and dimethylacetamide. More preferably, those having a boiling point of 100 ° C. or lower are preferable in view of the subsequent step of removing the solvent. Specific examples include acetone, methyl ethyl ketone, ethyl acetate, and isopropanol. These may be used in combination of two or more.

  The polymerization initiator is not particularly limited as long as it is radically decomposed by heat or a reducing substance to cause addition polymerization to the monomer. For example, azobisisobutyronitrile, benzoyl peroxide, t-butyl perbenzoate, t-butyl hydroperoxide, di-t-butyl peroxide, cumene hydroperoxide, etc. are used alone or in combination. Can do. In addition, a chain transfer agent such as octyl mercaptan or dodecyl mercaptan can be added to adjust the molecular weight of the resin.

  As a specific polymerization method for the component (a), an ethylenically unsaturated monomer (a1) and a carboxyl group (and optionally a tertiary amino group) -containing ethylenically unsaturated monomer are used in a solvent in the presence of a radical polymerization initiator. Monomer dropping method in which a mixture of (a2) is dropped; a one-bath polymerization method in which a mixture comprising a solvent, a radical polymerization initiator, and monomers (a1) and (a2) is radicalized (polymerization is performed by charging monomers and the like in a lump. Method). From the viewpoint of safety and control of molecular weight, the monomer dropping method is preferred.

  Specific examples of the component (a) of the present invention include copolymers composed of methyl methacrylate, 2-ethylhexyl acrylate, acrylic acid and dimethylaminoethyl methacrylate.

<(B) component>
The alkoxy group-containing organosilane compound used as the component (b) has the following general formula (1),

(Wherein R ¹ is a hydrogen atom or an alkyl group, and R ² , R ³ and R ⁴ are each independently a hydrogen atom, OR ¹ , an alkyl group or an aryl group) A condensate is preferred. In addition, when it is a condensate, the range of 2-100 is common as the condensation degree, and the liquid thing whose condensation degree is 2-15 is preferable from a compatible point. Moreover, in this invention, the alkoxy group containing organosilane compound which is (b) component is good also as one type, and may combine 2 or more types. In addition, "organosiloxane" said in this specification and the claim attached to this specification is processing the alkoxy group containing organosilane compound which is (b) component by the hydrolysis condensation process explained in full detail behind. The resulting product. The “organosiloxane” may be one obtained by hydrolytic condensation of an alkoxy group-containing organosilane compound with about 2 to several hundred molecules.

  Specific examples of the silane compound represented by the general formula (1) include tetramethoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, n-propyltrimethoxysilane, isopropyltrimethoxysilane, and γ-chloropropyltrimethoxy. Silane, 3,3,3-trifluoropropyltrimethoxysilane, phenyltrimethoxysilane, dimethyldimethoxysilane, diethyldimethoxysilane, diphenyldimethoxysilane, methylphenyldimethoxysilane, dimethyldipropoxysilane and the like, more preferably Examples include methyltrimethoxysilane, phenyltrimethoxysilane, and dimethyldimethoxysilane.

  Specific examples of the condensate of the silane compound represented by the general formula (1) include methyl silicate 51, methyl silicate 56 (above, Mitsubishi Chemical Corporation product), DC3074, DC3037, SR2402 (toe, Toray Dow Corning Silicone Co., Ltd.), KR9218, KR500, KR400, X40-9225, KR-213, KR-217, KR-510, X40-9227, X40-9247 (above, Shin-Etsu Chemical Co., Ltd. products) Etc. can be illustrated.

<(C) component>
Specific examples of the organometallic compound used as the component (c) include metal alkoxide compounds such as Ti, Al, Zr, and Sn, metal chelate compounds, and metal ester compounds. Examples of the metal alkoxide compound include aluminum trimethoxide, aluminum triethoxide, aluminum tri-n-propoxide, aluminum triisopropoxide, aluminum tri-n-butoxide, aluminum triisobutoxide, aluminum tri-sec-butoxide. , Aluminum alkoxides such as aluminum tri-tert-butoxide; tetramethyl titanate, tetraethyl titanate, tetra-n-propyl titanate, tetraisopropyl titanate, tetra-n-butyl titanate, tetraisobutyl titanate, tetra-tert-butyl titanate, tetra- titanium alkoxides such as n-hexyl titanate, tetraisooctyl titanate, tetra-n-lauryl titanate; Ethyl zirconate, tetra-n-propyl zirconate, tetraisopropyl zirconate, tetra-n-butyl zirconate, tetra-sec-butyl zirconate, tetra-tert-butyl zirconate, tetra-n-pentyl zirconate, tetra Zirconium alkoxides such as -tert-pentyl zirconate, tetra-tert-hexyl zirconate, tetra-n-heptyl zirconate, tetra-n-octyl zirconate, tetra-n-stearyl zirconate; and dibutyltin dibutoxide Examples of metal chelate compounds include tris (ethyl acetoacetate) aluminum, tris (n-propyl acetoacetate) aluminum, tris (isopropyl acetoacetate) aluminum, (N-butylacetoacetate) aluminum, isopropoxy bis (ethylacetoacetate) aluminum, tris (acetylacetonato) aluminum, tris (proponylacetonato) aluminum, diisopropoxypropionylacetonatoaluminum, monoacetylacetonato・ Aluminum chelate compounds such as bis (propionylacetonato) aluminum, monoethyl acetoacetate ・ bis (acetylacetonato) aluminum, diisopropoxyethyl acetoacetate aluminum, monoacetylacetona bis (ethylacetoacetate) aluminum; Propoxy bis (ethyl acetoacetate) titanate, diisopropoxy bis (acetylacetonato) titanate, di-n-butoxy bis Titanium chelate compounds such as (acetylacetonato) titanate; zirconium chelate compounds such as tetrakis (acetylacetonato) zirconium, tetrakis (n-propylacetoacetate) zirconium, tetrakis (ethylacetoacetate) zirconium; dibutyltin bis (acetylacetonate) Examples of the metal ester compound include dibutyltin diacetate, dibutyltin di (2-ethylhexylate), dibenzyltin di (2-ethylhexylate), dibutyltin dilaurate, and dibutyltin diester. Examples include tin ester compounds such as isooctyl maleate. Dibutyltin bis (trimethoxysilicate), dibutyltin bis (triethoxysilicate), dibutyltin bis (tributoxysilicate), dioctyltin bis (trimethoxysilicate), dioctyltin bis (triethoxysilicate), dioctyltin bis (Tributoxysilicate), dibutyltin bis (methyldiethoxysilicate), dibutyltin bis (ethyldiethoxysilicate), dibutyltin bis (butyldiethoxysilicate), dioctyltin bis (methyldiethoxysilicate), dioctyltin bis ( Ethyl diethoxysilicate), dioctyl tin bis (butyl diethoxy silicate), dibutyl tin bis (dimethyl ethoxy silicate), dibutyl tin bis (diethyl ethoxy silicate), dibutyl tin bis (dibutyl eth Silicate), dioctyltin bis (dimethylethoxysilicate), dioctyltin bis (diethylethoxysilicate), dioctyltin bis (dibutylethoxysilicate), dilauryltin bis (dimethylethoxysilicate), dilauryltin bis (diethylethoxysilicate), dilauryltin Dialkyl tin bissilicates such as bis (dibutylethoxysilicate) can also be used. These organometallic compounds can be used alone or in combination of two or more.

<(D) component>
As the urethane prepolymer of component (d), one having at least two tertiary amino groups in one molecule and an amine value of 10 to 350 mgKOH / g is used.

  The urethane prepolymer of component (d) has a number average molecular weight (in terms of standard polystyrene) of 500 to 30000 from the viewpoint of compatibility with other components (particularly components (a) and (b)) in the coating composition. It is preferable that it is, More preferably, it is 1000-20000. Furthermore, the tertiary amino compound (d2) having an active hydrogen group in the polyisocyanate compound (d1) having an isocyanate group at the terminal in terms of providing flexibility to the obtained coating film and improving flex resistance and adhesion. It is preferable to use a urethane prepolymer obtained by urethanization reaction.

  Here, as the polyisocyanate compound (d1), aromatic diisocyanates such as tolylene diisocyanate (TDI), xylylene diisocyanate (XDI), diphenylmethane diisocyanate (MDI), polymeric MDI, trimethylene diisocyanate, 1,6-hexa Aliphatic polyisocyanates such as methylene diisocyanate (HMDI), methyl-2,6-diisocyanate hexanoate (lysine diisocyanate, LDI), 2-isocyanatoethyl-2,6-diisocyanate caproate (lysine triisocyanate, LTI), Alicyclics such as isophorone diisocyanate (IPDI), norbornane diisocyanate (NBDI) hydrogenated xylylene diisocyanate, hydrogenated diphenylmethane diisocyanate Examples thereof include reisocyanates or terminal isocyanate group compounds obtained by reacting these modified products with compounds having active hydrogen groups such as polyester polyols, polycarbonate polyols, polyether polyols, polyolefin polyols, animal and plant-based polyols or copolyols thereof. .

  The polyester polyols used here include succinic acid, adipic acid, sebacic acid, azelaic acid, terephthalic acid, isophthalic acid, orthophthalic acid, hexahydroterephthalic acid, hexahydroisophthalic acid, hexahydroorthophthalic acid, naphthalene dicarboxylic acid One or more of acid, 1,4-cyclohexanedicarboxylic acid, polycarboxylic acid such as trimetic acid, acid ester, or acid anhydride, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1, 2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, 1,4-cyclohex Polyester polyols obtained by dehydration condensation with one or more low molecular polyols such as dimethyl methanol, trimethylolpropane, glycerin, pentaerythritol, etc., and low molecular polyols, low molecular polyamines, low molecular amino alcohols as initiators, Examples include lactone polyester polyols obtained by ring-opening polymerization of cyclic ester monomers such as ε-caprolactone and γ-valerolactone.

  Examples of the polycarbonate polyol include those obtained by a dealcoholization reaction, a dephenol reaction, or the like between a low molecular polyol and diethylene carbonate, dimethyl carbonate, diethyl carbonate, diphenyl carbonate, or the like.

  As the polyether polyol, polyethylene glycol, polypropylene glycol, polytetramethylene ether obtained by ring-opening polymerization of ethylene oxide, propylene oxide, tetrahydrofuran, etc. using low molecular polyol, low molecular polyamine, low molecular amino alcohol as an initiator. Examples thereof include glycols and copolymers thereof.

  Examples of the polyolefin polyol include hydroxyl group-containing polybutadiene, hydroxyl group-containing polyisoprene, or hydrogenated products thereof, hydroxyl group-containing chlorinated polypropylene, and hydroxyl group-containing chlorinated polyethylene.

  Examples of animal and plant-based polyols include castor oil-based polyols and silk fibroin.

  The molecular weight of these polyols is 300 to 10,000, preferably 400 to 4000.

  On the other hand, the component (d2) is not particularly limited as long as it has an active hydrogen group and a tertiary amino group. Specifically, N, N-dimethylethanolamine, N, N-diethylethanolamine, Examples thereof include amino alcohols such as N, N-dibutylethanolamine and N-methyldiethanolamine.

  As a specific method for synthesizing the component (d), a polyol component and an isocyanate component are reacted in an organic solvent having a boiling point of 100 ° C. or lower and inert to an isocyanate group such as acetone, methyl ethyl ketone, and ethyl acetate. There is a method in which the component (d2) is added to the component (d1) and added to obtain the component (d). In addition, the addition amount of the component (d2) is suitably such that the active hydrogen group in the component (d2) is 0.8 to 1.2 mol with respect to 1 mol of the isocyanate group in the component (d1).

As the component (d) of the present invention, specifically, urethane obtained by adding N, N-dimethylethanolamine (component (d2)) to a reaction product (component (d1)) of polypropylene glycol and HMDI. Examples include prepolymers. This is expressed as the following formula (2) (where n = 0 to 200).

<Epoxy group-containing organosilane compound>
The epoxy group-containing organosilane compound constituting the second liquid is not particularly limited, and specifically, glycidoxymethyltrimethoxysilane, glycidoxymethyltriethoxysilane, β-glycidoxyethyltrimethoxysilane. , Β-glycidoxyethyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyl (methyl) dimethoxysilane, γ-glycidoxypropyl ( Dimethyl) methoxysilane, γ-glycidoxypropyl (ethyl) dimethoxysilane, (3,4-epoxycyclohexyl) methyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxy Polysiloxane etc. can be mentioned. Alternatively, these hydrolysis condensates can also be used. Among these, γ-glycidoxypropyltriethoxysilane is preferable from the viewpoint of compatibility and reactivity.
The alkoxy group-containing organic silane compound and organosiloxane, which are the component (b) described above, do not contain any epoxy groups, as is apparent from the examples of the alkoxy group-containing organic silane compounds. It is clearly distinguished from a silane compound.

  In the present invention, the epoxy group-containing organic silane compound constituting the second liquid is an epoxy group-containing unsaturated monomer such as γ- (meth) acryloxypropylmethoxysilane and glycidyl (meth) acrylate, and hydrolysis. A copolymer with a polymerizable silyl group-containing unsaturated monomer can also be used.

<Compound having at least two epoxy groups in one molecule>
In the two-component curable aqueous coating composition of the present invention, at least 2 epoxy groups other than the epoxy group-containing organic silane compound are contained in one molecule for the purpose of further improving the bending resistance and crack resistance of the coating film. You may mix arbitrarily the compound which has one or more into a 2nd liquid as a crosslinking agent.
Such a compound having at least two epoxy groups in one molecule is water-soluble or water-dispersible, and can have an epoxy equivalent of 50 to 1000, more preferably 100 to 500. .

Here, the epoxy equivalent can be determined by the following method. First, about 0.2 to 1 g of the epoxy compound is precisely weighed and dissolved in 90 ml of methyl ethyl ketone at room temperature to obtain a sample solution. To this, about 10 ml of glacial acetic acid, 1.0 g of CTAB (cetyltrimethylammonium bromide), and 10 to 15 drops of CV (crystal violet) solution (indicator) are added with 0.1 N perchloric acid standard solution while stirring. Titrate until a blue-green color is exhibited. The end point is a point where blue-green color lasts 1 minute. A blank test is performed in the same manner, and the epoxy equivalent (WPE) of the epoxy group-containing compound is obtained by the following formula.

W: Weight of sample (g)
Vs: Amount of 0.1N perchloric acid standard solution used (drop amount) ml number Vb: Amount of perchloric acid standard solution used in blank test (drop amount) ml number N: Normality of perchloric acid solution

  The compound having at least two epoxy groups in one molecule is not particularly limited, and specifically, sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, diglycerol polyglycidyl ether, trimethylolpropane poly Examples thereof include polyfunctional epoxy compounds such as glycidyl ether, polyethylene glycol diglycidyl ether, and polypropylene glycol diglycidyl ether.

  The coating composition of the present invention may appropriately contain a color pigment and an extender pigment in addition to the above components.

  Color pigments include titanium oxide, zinc oxide, carbon black, ferric oxide (bengala), yellow lead, yellow iron oxide, ocher, ultramarine, cobalt green and other inorganic pigments, azo, naphthol, pyrazolone, Examples include organic pigments such as anthraquinone, perylene, quinacridone, disazo, isoindolinone, benzimidazole, phthalocyanine, and quinophthalone.

  Examples of extender pigments include heavy calcium carbonate, clay, kaolin, talc, precipitated barium sulfate, barium carbonate, white carbon, and diatomaceous earth.

  Furthermore, in the coating composition of the present invention, a plasticizer, an antiseptic, a fungicide, an algae, an antifoaming agent, a leveling agent, a pigment dispersant, an antisettling agent, as long as the object of the present invention is not impaired. Additives for coating materials such as sagging inhibitors, thickeners, matting agents, film forming aids, antifreezing agents, light stabilizers, pH adjusters, ultraviolet absorbers, and photocatalytic titanium oxides can be appropriately blended.

  Moreover, it is also preferable to mix | blend colloidal silica with the coating composition of this invention suitably for the purpose of improving the stain resistance of a coating film obtained, a flame retardance, and coating-film hardness.

  Regarding the production of the aqueous emulsion constituting one liquid of the two-part curable aqueous coating composition of the present invention, explanation will be added below.

The component ratio of the mixture of the acrylic copolymer (component (a)) and the alkoxy group-containing organic silane compound (component (b)) is (a) relative to 100 parts by weight (solid content) of component (b). It is preferable that it is 20-200 weight part (solid content) of a component. When the amount of component (b) increases, the flexibility of the coating film decreases and adversely affects the bending resistance and the like, while when it decreases, the weather resistance and stain resistance of the coating film decrease.
In addition, in the step of hydrolytic condensation in the presence of water and an organometallic compound for the mixture of the component (a) and the component (b), the organometallic is used with respect to 100 parts by weight (solid content) of the component (b). The compound (component (c)) is preferably present in an amount of 0.1 to 30 parts by weight.

  In the step of mixing a urethane prepolymer (component (d)) having at least two tertiary amino groups in one molecule and an amine value of 10 to 350 mgKOH / g in the system, It is preferable to mix 5 to 50 parts by weight (solid content) of component (d) with respect to 100 parts by weight (solid content) (component (b)) used in the process. When the amount of the component (d) is reduced, the flexibility of the coating film is lowered and adversely affects the bending resistance and the like, while when it is increased, the weather resistance and stain resistance of the coating film are lowered.

  In the production of the aqueous emulsion according to the present invention, one of the advantages of adding the urethane prepolymer (component (d)) is that the urethane prepolymer is stable in the aqueous emulsion and has flexibility. It is possible to provide a coating composition that is capable of imparting crack resistance and flex resistance to the coating film and is water-based. And the further advantage of adding a urethane prepolymer is that it also has a film-forming auxiliary effect, so that the organic solvent can be greatly reduced, contributing to low VOC.

The step of subjecting a mixture of an acrylic copolymer (component (a)) and an alkoxy group-containing organic silane compound (component (b)) to hydrolytic condensation in the presence of water and an organometallic compound is performed under normal pressure, 50 It is appropriate to carry out at a temperature of -80 ° C for 3-8 hours. The progress of hydrolysis condensation can be confirmed by quantifying the alcohol produced by the reaction by gas chromatography.
When the hydrolytic condensation step is not performed in the presence of such an organometallic compound, the stability as an emulsion is poor, and the two layers are separated during storage or the viscosity is remarkably increased.

  After mixing the urethane polymer in the reaction system, in the step of neutralizing and self-emulsifying by adding a neutralizing agent and water, the neutralizing agent may be added and uniformly dispersed and neutralized to add water. Alternatively, an aqueous emulsion may be obtained by simultaneously adding a neutralizing agent and water and forcibly dispersing by stirring. Examples of the neutralizing agent include ammonia, triethylamine, triethanolamine, monoethanolamine, N-methyldiethanolamine, N, N-dimethylethanolamine, morpholine, and the like.

  About the addition amount of the neutralizing agent, 50 to 100%, preferably 70 to 90%, of the amount obtained by subtracting the tertiary amino group from the carboxyl group in the system (molar conversion) so as to obtain a stable aqueous emulsion. An amount that can be neutralized is suitable. Further, the amount of water added is arbitrarily determined in consideration of the coating workability when it is used as a coating composition, but is usually such an amount that the solid content of the coating composition is 10 to 50% by mass. Is appropriate.

  In the aqueous emulsion thus obtained, the alcohol produced by the hydrolysis condensation reaction remains. In addition, since an acrylic copolymer liquid polymerized in a solvent is used, if the aqueous emulsion is used as it is in a coating composition, the volatile organic components increase. It may be removed below.

  As described above, the coating composition of the present invention comprises the first liquid and the second liquid. In use, the first liquid and the second liquid may be mixed and stirred at the time of use. In addition, there is no restriction | limiting in particular also about the mixing ratio of a 1st liquid and a 2nd liquid. Moreover, it is preferable that the pot life as a coating material is 3 to 8 hours.

  The coating composition of the present invention is suitably used in machinery, ships, vehicles, aircraft, civil engineering, construction, heavy anticorrosion, inks, and other general industrial fields because it has room temperature curing and low contamination and high weather resistance. In particular, when the coating composition of the present invention is used, it becomes possible to obtain a coating film having excellent bending resistance and crack resistance, so that it is suitable for construction and civil engineering structures having many members having high flexibility. It is suitable for these materials. Moreover, the coating composition of this invention can be used suitably also for the ceramic industry type | system | group of a detached house and the metal-type siding material in which the maintenance of the coating-film performance over 10-20 years is calculated | required. Furthermore, as described above, since it is a water-based paint composition considering the environment and safety, it can also be used in a living room.

  As described above, in the coating composition of the present invention, the manufacturing method including the step of mixing the urethane prepolymer does not impair the original weather resistance and stain resistance of the organopolysiloxane-based paint, and does not deteriorate the bending resistance and resistance. A two-component curable aqueous coating composition having excellent cracking properties can be obtained.

(Example)
Hereinafter, the present invention will be described in more detail, but the present invention is not limited to these examples. First, the physical property evaluation method of the coating composition used by an Example and a comparative example is demonstrated. In the following, “parts” and “%” mean “parts by weight” and “% by weight”, respectively, unless otherwise specified.

<Flexibility>
Evaluation of bending resistance was based on the method of JIS K5600-5-1, and a mandrel having a diameter of 10 mm was used. In addition, as a test piece, a coating composition was sprayed on a 150 × 50 × 0.3 mm steel plate so that the dry coating thickness was 50 μm, and cured for 4 days under conditions of 23 ° C. and 50% RH. Then, what was further subjected to forced drying at 80 ° C. for 3 days was used. The evaluation was made by visually observing the bent part of the coating film, with “◯” indicating that the test piece did not crack or peel off, and “X” indicating the others.

<Crack resistance (wet cold / heat repeatability)>
The crack resistance was immersed in 20 ° C. water for 18 hours in accordance with JIS K5660 6.14 (wet and cold repeatability test), and then heated at −20 ° C. freezer for 3 hours and further at 50 ° C. for 3 hours. . This cycle was repeated for 30 cycles. The state of the coating film after the test was visually observed, and the degree of cracking, swelling and whitening in the coating film was evaluated in the following three stages. The test piece was coated with a cationic primer (trade name: cationic primer, manufactured by Asia Industries Co., Ltd.) on a 70 × 70 × 6 mm flexible board with a spray so that the dry film thickness was 20 μm. Drying was performed for 1 day under the condition of 50% RH. Further, the coating composition was applied by spraying so that the dry film thickness was 50 μm, and was cured for 7 days under conditions of 23 ° C. and 50% RH.
○: No change is observed in the coating film.
(Triangle | delta): A crack and swelling are recognized in a part of coating film.
X: Remarkable cracking and swelling are observed in the coating film.

<Accelerated weather resistance>
The accelerated weathering test was performed using a super accelerated weathering tester (Isuperki UV Tester manufactured by Iwasaki Electric Co., Ltd.). The test piece was sprayed on a 50 × 50 × 4 mm flexible board with a cationic primer (trade name: cationic primer, manufactured by Asia Kogyo Co., Ltd.) so that the dry film thickness was 20 μm. Drying was performed for 1 day under the condition of 50% RH. Further, the coating composition was applied by spraying so that the dry film thickness was 50 μm, and dried for 7 days under conditions of 23 ° C. and 50% RH. As test conditions, a wavelength of 295 to 450 nm, an ultraviolet ray irradiation degree of 100 mW / cm ² , a black panel temperature of 63 ° C., 50% RH, one cycle was irradiation for 4 hours, and dew condensation was 4 hours, and 125 cycles (1000 hours) were tested. After completion of the test, the gloss retention with respect to the initial 60-degree specular gloss value of the coating film was determined and evaluated in the following three stages.
○: Gloss retention 70% or more △: Gloss retention 50% or more but less than 70% ×: Gloss retention 50% or less

<Alkali resistance>
In the alkali resistance test, the test piece was immersed in a saturated calcium hydroxide solution at 23 ° C. for 10 days in accordance with JIS K5660 6.21. After soaking, the test piece was gently washed with running water and dried for 2 hours, and the swelling, cracking, peeling and gloss change of the coating film were visually observed and evaluated in three stages. In addition, as a test piece, a cationic primer (trade name: cationic primer, manufactured by Asia Kogyo Co., Ltd.) was applied to a 150 × 70 × 4 mm flexible board with a spray so that the dry film thickness was 20 μm, and 23 ° C. , And dried for 1 day under the condition of 50% RH. Furthermore, the coating composition was applied by spraying so that the dry film thickness was 50 μm, and dried for 14 days under the conditions of 23 ° C. and 50% RH.
○: There is no significant change compared to the current specimen.
Δ: Slightly glossy compared to the current test piece.
X: Significant glossiness, cracking, and peeling compared to the current test piece.

<Adhesiveness>
The adhesion test was performed in accordance with JIS K5600-5-6 cross-cut method, using a cutter guide with a gap interval of 2 mm to cut a grid pattern (25 squares; 5 vertical sections x 5 horizontal sections). A cellophane adhesive tape was put on the substrate, and the tape was peeled off in a direction perpendicular to the coating surface while holding one end of the tape, and the peeled area of the coating film was measured. In addition, as a test piece, a coating composition was spray-coated on a 150 × 70 × 4 mm flexible board so that the dry coating thickness was 50 μm, and dried for 14 days under conditions of 23 ° C. and 50% RH. Was used. The adhesion was evaluated as follows from the area of peeling of the coating film relative to the total area of the coating film.
○: When the area of the coating film is less than 5% of the total area Δ: When the area of the coating film is 5% or more and less than 35% of the total area ×: The area of the coating film is the total area In case of 35% or more

<Forced contamination>
A coating composition was spray-coated on an aluminum plate of 150 × 70 × 0.8 mm so that the dry coating thickness was 50 μm, and dried for 14 days under conditions of 23 ° C. and 50% RH to prepare a test piece. . Carbon suspension water (dispersion liquid in which glass beads are added to 95 parts of carbon black Color Black FW200 and 95 parts of deionized water and dispersed in a paint shaker for 2 hours with a paint shaker) is concealed by air spray. And then immediately dried at 60 ° C. for 1 hour. After drying, the sample was allowed to cool to room temperature, and the surface of the test piece was washed with running gauze under running water until the soiled material did not fall off. After washing, the film was dried at room temperature for 3 hours, the degree of soiling was measured with a color difference meter, and the difference in lightness (ΔL *) of the coating film before and after the test was determined and evaluated in the following three stages. In addition, it shows that it is a coating material excellent in stain resistance, so that the absolute value of a brightness difference is small.
Lightness difference (ΔL *)
= [Coating film brightness after test (L * 1) -Coating film brightness before test (L * 0)]
○: Lightness difference −5 or more Δ: Lightness difference −10 or more and less than −5 ×: Lightness difference −10 or less

<Comprehensive evaluation>
Based on the performance measurement results of the coating composition shown above, a comprehensive evaluation of the coating composition was performed according to the following criteria.
○: All are evaluations of ○, and can be used very suitably as a coating composition.
(Triangle | delta): Although there exists evaluation of (triangle | delta) and it is a level which can be used as a coating composition, the use may be limited.
X: A level that is evaluated as x and difficult to use as a coating composition.

Next, the component mix | blended with a coating composition is demonstrated.
First, synthesis examples ((a-1) and (a-2)) of an acrylic copolymer (acrylic resin solution) will be described.
<Synthesis Example / Acrylic Resin Solution (a-1)>
A reactor equipped with a stirrer, a thermometer, a cooling tube, a nitrogen gas inlet tube, and a dropping device was charged with 400 parts of methyl ethyl ketone and heated to 80 ° C. while stirring. A mixture comprising 270 parts of methyl methacrylate, 185 parts of 2-ethylhexyl acrylate, 30 parts of acrylic acid, 15 parts of dimethylaminoethyl methacrylate, 4 parts of azobisisobutyronitrile, and 10 parts of methyl ethyl ketone was dropped over 3 hours. did. After completion of the dropwise addition, the reaction was carried out at the same temperature for 1 hour. Further, a mixture consisting of 1 part of azobisisobutyronitrile and 95 parts of methyl ethyl ketone was added dropwise over 1 hour. After completion of the dropwise addition, the mixture was reacted at the same temperature for 3 hours. Nonvolatile content (solid content) 50%, viscosity 3200 mPa · s (25 ° C.), number average molecular weight 20000, solid content amine value 10.6 mgKOH / g, solid content acid value 46 A pale yellow transparent tertiary amino group- and carboxyl group-containing acrylic resin solution (a-1) of 3 mgKOH / g was obtained.

<Synthesis Example / Acrylic Resin Solution (a-2)>
A reactor equipped with a stirrer, a thermometer, a cooling tube, a nitrogen gas inlet tube, and a dropping device was charged with 400 parts of methyl ethyl ketone and heated to 80 ° C. while stirring. A mixture comprising 280 parts of methyl methacrylate, 190 parts of 2-ethylhexyl acrylate, 30 parts of acrylic acid, 4 parts of azobisisobutyronitrile and 10 parts of methyl ethyl ketone was added dropwise over 3 hours. After completion of the dropwise addition, the reaction was carried out at the same temperature for 1 hour. Further, a mixture consisting of 1 part of azobisisobutyronitrile and 95 parts of methyl ethyl ketone was added dropwise over 1 hour. After completion of dropping, the mixture was reacted at the same temperature for 3 hours. Nonvolatile content (solid content) 50%, viscosity 800 mPa · s (25 ° C.), number average molecular weight 10,000, solid content amine value 0 mgKOH / g, solid content acid value 46.3 mgKOH / G of a light yellow transparent carboxyl group-containing acrylic resin solution (a-2) was obtained.

Next, synthesis examples ((d-1) to (d-3)) of the tertiary amino group-containing urethane prepolymer will be described.
<Synthesis example / tertiary amino group-containing urethane prepolymer (d-1)>
In a reactor equipped with a stirrer, a thermometer, a cooling tube and a nitrogen gas introduction tube, and a dropping device, polypropylene glycol (trade name: Sannix PP-1000, manufactured by Sanyo Chemical Industries, Ltd .: molecular weight = 1000) 527.9 Part, 1,6-hexamethylene diisocyanate 177.8 parts and methyl ethyl ketone 200 parts were added, the temperature was raised to 80 ° C. with stirring in a nitrogen atmosphere, and the reaction was continued at the same temperature for 6 hours or more. When the isocyanate concentration (NCO%) reached the theoretical amount, 94.3 parts of N, N-dimethylethanolamine was further added and reacted until the isocyanate group disappeared by infrared absorbance analysis. A tertiary amino group-containing urethane prepolymer solution (d-1) having a solid content of 80 wt% and a solid content amine value of 74.2 mg KOH / g was obtained.

<Synthesis example / tertiary amino group-containing urethane prepolymer (d-2)>
In a reactor equipped with a stirrer, a thermometer, a cooling tube and a nitrogen gas introduction tube, and a dropping device, 566.7 parts of polycaprolactone diol (trade name: Plaxel L212AL, manufactured by Daicel Chemical Industries, Ltd .: molecular weight = 1250) and 1 , 6-hexamethylene diisocyanate 152.5 parts and methyl ethyl ketone 200 parts were charged, heated to 80 ° C. with stirring under a nitrogen atmosphere, and reacted at the same temperature for 6 hours or more. When the isocyanate concentration (NCO%) reached the theoretical amount, 80.8 parts of N, N-dimethylethanolamine was further added and reacted until the isocyanate group disappeared by infrared absorbance analysis. A tertiary amino group-containing urethane prepolymer solution (d-2) having a solid content of 80 wt% and a solid content amine value of 63.6 mg KOH / g was obtained.

<Synthesis example / tertiary amino group-containing urethane prepolymer (d-3)>
In a reactor equipped with a stirrer, a thermometer, a cooling tube, a nitrogen gas introduction tube, and a dropping device, 493.0 parts of polycarbonate diol (trade name: Nipponporan 981, manufactured by Nippon Polyurethane Industry Co., Ltd .: molecular weight = 1000) and isophorone 219.1 parts of diisocyanate and 200 parts of methyl ethyl ketone were charged, heated to 80 ° C. with stirring under a nitrogen atmosphere, and reacted at the same temperature for 6 hours or more. When the isocyanate concentration (NCO%) reached the theoretical amount, 87.9 parts of N, N-dimethylethanolamine was further added and reacted until the isocyanate group disappeared by infrared absorbance analysis. A tertiary amino group-containing urethane prepolymer solution (d-3) having a solid content of 80 wt% and a solid content amine value of 69.1 mg KOH / g was obtained.

Other components will be described.
As the alkoxy group-containing organosilane compound of component (b), a methylphenyl alkoxysilane compound (trade name: DC3074, manufactured by Toray Dow Corning Silicone Co., Ltd., active ingredient 100%, methoxy content 17 wt%, Si atom About 25%).
As the organometallic compound of component (c), dibutyltin dilaurate (DBTDL) was used.

In addition, the first liquid includes a pigment paste, a thickener (trade name: Primal RM-8W, manufactured by Rohm and Haas Japan Co., Ltd.), and a film forming aid (trade name: Kyowanol M, Kyowa Hakko). Kogyo Co., Ltd.) was used. In addition, the pigment paste is made of 110 parts of ion-exchanged water, 10 parts of a dispersant (trade name: SN Dispersant 5468, manufactured by San Nopco Co., Ltd.) and a defoaming agent (trade name: DK Q1-072, Dow Corning ( 5 parts), titanium oxide (trade name: Taipei CR-97, Ishihara Sangyo Co., Ltd.) 375 parts and glass beads 500 parts were added and dispersed for 30 minutes in a bead mill. After the dispersion, the glass beads were removed to obtain a pigment paste having a solid content of 75%.
Furthermore, as the crosslinking agent of the second liquid, γ-glycidoxypropyltriethoxysilane (trade name: KBE-403, manufactured by Shin-Etsu Chemical Co., Ltd.) and, in some cases, sorbitol polyglycidyl ether (trade name: Denacol) EX-614B, manufactured by Nagase ChemteX Corporation) was used.

The hydrolysis condensation step in the production of the aqueous emulsion is performed as follows. Here, as an example, the hydrolysis-condensation step in the production of emulsion A in Table 1 described below will be described, but the hydrolysis-condensation step in the production of other aqueous emulsions is similarly performed.
<Hydrolysis condensation>
In a reactor equipped with a stirrer, a thermometer, a condenser, and a dropping device, 100 parts of a tertiary amino group- and carboxyl group-containing acrylic resin solution ((a-1)) and a methylphenyl-based alkoxysilane compound (b) 100 And 20 parts of ion exchange water were charged and mixed with stirring. Further, 3 parts of dibutyltin dilaurate (c) was added while stirring, the temperature was raised to 70 ° C., and the reaction was performed at the same temperature for 6 hours.

The urethane prepolymer mixing step and the neutralization / self-emulsification step in the production of the aqueous emulsion are performed as follows. Here, as an example, the urethane prepolymer mixing step and the neutralization / self-emulsification step in the production of emulsion A in Table 1 described below will be described. The emulsification step is performed in the same manner.
<Urethane prepolymer mixing step and neutralization / self-emulsification step>
Following the hydrolysis-condensation step, the mixture was cooled to 35 ° C., 17.2 parts of tertiary amino group-containing urethane prepolymer solution ((d-1)), N.I. After 1.9 parts of N-dimethylethanolamine was charged and sufficiently neutralized, 219.5 parts of ion-exchanged water was charged and emulsified. Thereafter, methyl ethyl ketone and methanol produced by the reaction were removed at 60 ° C. × 100 Torr to obtain an aqueous emulsion having a solid content of 40% and an average particle size of 140 nm.

<Preparation of aqueous emulsion>
Emulsions A to H were prepared according to the composition described in Table 1 and according to the steps described above. “Desolvation” means that methyl ethyl ketone (MEK) and generated methanol (MeOH) added during the production process are removed.
Emulsions A to F are in accordance with the present invention, and emulsions G to H are prepared for comparison. Since emulsion H was not subjected to the hydrolysis step in the presence of dibutyltin dilaurate, the emulsion was poor in stability and separated into two layers.

<Preparation of the first liquid and the second liquid>
According to the composition described in Table 2, each of the first liquid and the second liquid was prepared by stirring each component with a stirrer for 3 minutes (Examples 1 to 9: Examples 1 to 7 are in accordance with the present invention). Each of the items was tested according to the above-mentioned procedure. The test results are shown in the same table.

  As is apparent from the data in Table 2, the two-part curable coating composition using the aqueous emulsions A to F according to the present invention has flex resistance, crack resistance (wet and cold repeatability), and accelerated weather resistance. It can be said that it is a very practical coating composition because it forms an excellent coating film that is well-balanced with respect to each of the items of alkali resistance, adhesion, and forced contamination, and is water-based so that it is highly safe.

Claims (9)

A carboxyl group-containing acrylic copolymer, organosiloxane, having the following general formula (1)

(Wherein R ¹ is a hydrogen atom or an alkyl group, and R ² , R ³ and R ⁴ are each independently a hydrogen atom, OR ¹ , an alkyl group or an aryl group). Alternatively, an organosiloxane obtained by hydrolytic condensation of an alkoxy group-containing organosilane compound, which is a condensate thereof, in the presence of water and an organometallic compound, and a tertiary amino group having an active hydrogen group in a polyisocyanate compound having an isocyanate group at the terminal Two-component curable type comprising a first liquid composed of an aqueous emulsion containing a tertiary amino group-containing urethane prepolymer obtained by urethanizing a compound and a second liquid containing an epoxy group-containing organosilane compound Water-based paint composition.   The two-component curable aqueous coating composition according to claim 1, further comprising a compound having at least two epoxy groups in one molecule other than the epoxy group-containing organosilane compound in the second solution. Two-component curing comprising a first liquid composed of an aqueous emulsion containing a carboxyl group-containing acrylic copolymer, an organosiloxane and a tertiary amino group-containing urethane prepolymer, and a second liquid containing an epoxy group-containing organosilane compound Type water-based paint composition,
The aqueous emulsion containing the carboxyl group-containing acrylic copolymer, organosiloxane, and tertiary amino group-containing urethane prepolymer,
(I) a step of producing an acrylic copolymer having a carboxyl group and an acid value of 20 to 100 mgKOH / g by solution polymerization;
(Ii) A mixture of 20 to 200 parts by weight of the carboxyl group-containing acrylic copolymer and 100 parts by weight of an alkoxy group-containing organosilane compound is hydrolyzed in the presence of water and 0.1 to 30 parts by weight of an organometallic compound. A step of performing condensation,
The alkoxy group-containing organosilane compound has the following general formula (1)

(Wherein R ¹ is a hydrogen atom or an alkyl group, and R ² , R ³ and R ⁴ are each independently a hydrogen atom, OR ¹ , an alkyl group or an aryl group). Or the condensate described above,
(Iii) A tertiary amino group-containing urethane prepolymer 5 having at least two tertiary amino groups in one molecule and an amine value of 10 to 350 mgKOH / g in the product from step (ii) In the step of mixing 50 parts by weight, the tertiary amino group-containing urethane prepolymer is obtained by urethanizing a tertiary amino compound having an active hydrogen group to a polyisocyanate compound having an isocyanate group at the terminal. The above process ,
(Iv) A step of adding a neutralizing agent and water to the mixture from step (iii) to neutralize and self-emulsify,
The two-component curable aqueous coating composition.   The two-component curing according to claim 3, wherein the acrylic copolymer produced by the step (i) further has a tertiary amino group, and the amine value is larger than 0 mgKOH / g and not larger than 50 mgKOH / g. Type water-based paint composition. A method for producing an aqueous emulsion comprising a first liquid of a two-part curable aqueous coating composition comprising a first liquid composed of an aqueous emulsion and a second liquid containing an epoxy group-containing organosilane compound,
(I) A step of producing an acrylic copolymer (a) having a carboxyl group and an acid value of 20 to 100 mgKOH / g by solution polymerization,
(Ii) Water and an organometallic compound (c) 0.1 to 30 parts by weight with respect to a mixture of 20 to 200 parts by weight of the acrylic copolymer (a) and 100 parts by weight of an alkoxy group-containing organosilane compound (b) Hydrolytic condensation in the presence of
The alkoxy group-containing organosilane compound has the following general formula (1)

(Wherein R ¹ is a hydrogen atom or an alkyl group, and R ² , R ³ and R ⁴ are each independently a hydrogen atom, OR ¹ , an alkyl group or an aryl group). Or the condensate described above,
(Iii) A tertiary amino group-containing urethane prepolymer (d) having at least two tertiary amino groups in one molecule and an amine value of 10 to 350 mgKOH / g in the product from step (ii) ) A step of mixing 5 to 50 parts by weight , wherein the tertiary amino group-containing urethane prepolymer is a urethanization reaction of a tertiary amino compound having an active hydrogen group to a polyisocyanate compound having an isocyanate group at the terminal. Obtained by the above process ,
(Iv) a step of adding a neutralizer and water to the mixture from the step (iii) to neutralize and self-emulsify,
The method for producing an aqueous emulsion as described above.   The method according to claim 5, wherein the acrylic copolymer (a) further has a tertiary amino group, and the amine value is greater than 0 mgKOH / g and not greater than 50 mgKOH / g. A method for producing a two-component curable aqueous coating composition comprising:
An aqueous emulsion constituting the first liquid of the two-component curable aqueous coating composition,
(I) A step of producing an acrylic copolymer (a) having a carboxyl group and an acid value of 20 to 100 mgKOH / g by solution polymerization,
(Ii) Water and an organometallic compound (c) 0.1 to 30 parts by weight with respect to a mixture of 20 to 200 parts by weight of the acrylic copolymer (a) and 100 parts by weight of an alkoxy group-containing organosilane compound (b) Hydrolytic condensation in the presence of
The alkoxy group-containing organosilane compound has the following general formula (1)

(Wherein R ¹ is a hydrogen atom or an alkyl group, and R ² , R ³ and R ⁴ are each independently a hydrogen atom, OR ¹ , an alkyl group or an aryl group). Or the condensate described above,
(Iii) A tertiary amino group-containing urethane prepolymer (d) having at least two tertiary amino groups in one molecule and an amine value of 10 to 350 mgKOH / g in the product from step (ii) ) A step of mixing 5 to 50 parts by weight , wherein the tertiary amino group-containing urethane prepolymer is a urethanization reaction of a tertiary amino compound having an active hydrogen group to a polyisocyanate compound having an isocyanate group at the terminal. Obtained by the above process ,
(Iv) a step of adding a neutralizing agent and water to the mixture from step (iii) to neutralize and self-emulsify,
Including an epoxy group-containing organosilane compound in the second liquid of the two-part curable aqueous coating composition,
The method for producing the two-component curable aqueous coating composition.   The second liquid of the two-part curable aqueous coating composition further comprises a compound having at least two epoxy groups in one molecule other than the epoxy group-containing organosilane compound. the method of.   The method according to claim 7 or 8, wherein the acrylic copolymer (a) further has a tertiary amino group, and the amine value is larger than 0 mgKOH / g and not larger than 50 mgKOH / g.