JP2005200497A - Aqueous curable composition, paint and adhesive comprising the aqueous curable composition - Google Patents

Abstract

【Task】
The object of the present invention is excellent in adhesion to a base material or plastic base material having an old coating film with high hydrophobicity, has a sufficiently long pot life, and has sufficient hardness, appearance, water resistance, solvent resistance, etc. It is providing the aqueous curable composition which can form a coating film.
[Solution]
The present invention comprises a polyisocyanate (A) and an aqueous resin (B), wherein the aqueous resin (B) has a hydroxyl value of 10 to 200, and the aqueous resin (B) has a primary grade. The aqueous curable composition is characterized in that the molar ratio of the hydroxyl group to the secondary or higher hydroxyl group (primary hydroxyl group / secondary hydroxyl group) is 5/95 to 55/45.
[Selection figure] None

Description

  The present invention relates to an aqueous curable composition comprising a polyisocyanate and an aqueous resin that can be applied as an aqueous paint or an aqueous adhesive.

  In recent years, in the paint field, it has been strongly demanded to reduce the content of a volatile organic solvent contained in a curable composition applicable to a paint from the viewpoint of workability and environmental problems. In order to meet this demand, water-based organic solvent-based curable compositions have been attempted, for example, aqueous curing comprising a specific water-dispersible polyisocyanate composition and an aqueous resin having an active hydrogen-containing group. According to the adhesive composition, it has been reported that a cured product having excellent hardness, appearance, water resistance and adhesion can be provided (for example, see Patent Document 1).

  On the other hand, in recent years, development of an aqueous curable composition capable of exhibiting excellent performance in various applications has been demanded from the market. For example, aqueous curable compositions generally have poor adhesion to surfaces with low polarity, i.e. high hydrophobicity, specifically, repair coating on old hydrophobic coatings and automotive interiors. There is a need to develop an aqueous curable composition having excellent adhesion that can be applied to applications such as painting on plastic parts. Under such circumstances, when the aqueous curable composition is applied to the above-mentioned uses, it exhibits excellent adhesion to substrates such as wood and mild steel cocoons, but has a highly hydrophobic old coating film. Adhesiveness to substrates such as substrates and plastics is not yet sufficient, and development of an aqueous curable composition that can be applied as a paint having excellent adhesion is expected.

JP 2002-194045 A (Claim 15, paragraph “0145”)

  The object of the present invention is excellent in adhesion to a base material or plastic base material having an old coating film with high hydrophobicity, has a sufficiently long pot life, and has sufficient hardness, appearance, water resistance, solvent resistance, etc. It is providing the aqueous curable composition which can form a coating film.

  Moreover, the subject of this invention is providing the aqueous coating material and aqueous adhesive agent which are obtained using the said aqueous curable composition.

  It has been conventionally known that a primary hydroxyl group and a secondary or higher hydroxyl group can be used in combination with the aqueous resin contained in the aqueous curable composition. However, the present inventors have adjusted the molar ratio of (primary hydroxyl group / secondary or higher hydroxyl group) in the aqueous resin to a specific range, It has been found that excellent adhesion to a plastic substrate can be exhibited, and a coating film having good hardness and sufficient pot life can be obtained.

  That is, the present invention comprises a polyisocyanate (A) and an aqueous resin (B), the aqueous resin (B) has a hydroxyl value of 10 to 200, and the aqueous resin (B) has 1 The present invention relates to an aqueous curable composition characterized in that the molar ratio of the primary hydroxyl group to the secondary or higher hydroxyl group (primary hydroxyl group / secondary hydroxyl group) is 5/95 to 55/45. Preferably, the polyisocyanate (A) has water dispersibility, and preferably the molar ratio (isocyanate group of the polyisocyanate (A) / hydroxyl group of the aqueous resin (B)) is 0.5 to 3.0, preferably, the polyisocyanate (A) is an aliphatic polyisocyanate, and preferably the polyisocyanate (A) has an average of 3 or more oxyesters. It relates aqueous curable composition having a polyoxyethylene group consisting Len.

  The present invention also relates to an aqueous paint and an aqueous adhesive comprising the above-described aqueous curable composition.

  According to the present invention, the adhesive property of the aqueous curable composition, which has been considered to be poor in adhesion until now, is excellent in adhesion to a substrate having a highly hydrophobic old coating film or a highly hydrophobic plastic substrate. Is sufficiently long, and an aqueous curable composition having good hardness, appearance, water resistance, solvent resistance and the like can be obtained.

Hereinafter, the present invention will be described in more detail.
First, the polyisocyanate (A) used in the present invention will be described.

  Examples of the polyisocyanate (A) used in the present invention include various known and commonly used polyisocyanates. Broadly speaking, there are two types of polyisocyanates: hydrophobic polyisocyanates and water-dispersible polyisocyanates. Of the polyisocyanate (A), it is preferable to use a polyisocyanate having water dispersibility from the viewpoint of easy mixing with the aqueous resin (B).

  Examples of the polyisocyanate (A) include (1) a mixture of a polyisocyanate having water dispersibility and a hydrophobic polyisocyanate, and (2) a dispersant having no isocyanate group but having a hydrophilic group and a hydrophobic polyisocyanate. (1) water-dispersible polyisocyanate and hydrophobicity from the viewpoint of hardness, water resistance, and solvent resistance of a cured product obtained using the aqueous curable composition of the present invention. More preferably, a mixture with polyisocyanate is used.

  The hydrophobic polyisocyanate is one having no hydrophilic group such as various known anionic groups, cationic groups and nonionic groups in the molecule, such as 1,4-tetramethylene diisocyanate, Aliphatic diisocyanates such as ethyl (2,6-diisocyanato) hexanoate, 1,6-hexamethylene diisocyanate, 1,12-dodecamethylene diisocyanate, 2,2,4- or 2,4,4-trimethylhexamethylene diisocyanate Aliphatic triisocyanates such as 1,3,6-hexamethylene triisocyanate, 1,8-diisocyanate-4-isocyanate methyloctane, 2-isocyanatoethyl (2,6-diisocyanate) hexanoate;

  1,3- or 1,4-bis (isocyanatomethylcyclohexane), 1,3- or 1,4-diisocyanatocyclohexane, 3,5,5-trimethyl (3-isocyanatomethyl) cyclohexyl isocyanate, dicyclohexylmethane Alicyclic diisocyanates such as -4,4'-diisocyanate, 2,5- or 2,6-diisocyanatomethylnorbornane; 2,5- or 2,6-diisocyanatomethyl-2-isocyanate propylnorbornane Alicyclic diisocyanates such as m-xylylene diisocyanate, and aralkylene diisocyanates such as 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 Aromatic diisocyanates such as' -diisocyanate-3,3'-dimethyldiphenyl, 3-methyl-diphenylmethane-4,4'-diisocyanate, diphenylether-4,4'-diisocyanate; triphenylmethane triisocyanate, tris (isocyanate Aromatic triisocyanates such as natephenyl) thiophosphate;

  Polyisocyanates having a uretdione structure obtained by cyclizing and dimerizing the isocyanate groups of the various diisocyanates or triisocyanates described above; Isocyanates obtained by cyclizing and trimerizing the isocyanate groups of the various diisocyanates or triisocyanates described above A polyisocyanate having a nurate structure; a polyisocyanate having a burette structure obtained by reacting the aforementioned various diisocyanates or triisocyanates with water; an oxadiater obtained by reacting the various diisocyanates or triisocyanates with carbon dioxide Examples include polyisocyanates having a gintrione structure; polyisocyanates having an allophanate structure.

  Among these, when the aqueous curable composition of the present invention is used as an aqueous coating material, from the viewpoint of the weather resistance of the resulting coating film, aliphatic or alicyclic diisocyanates or triisocyanates, aralkylene diisocyanates or the like. It is preferable to use a derivative of

  Trifunctionals such as isocyanurate type polyisocyanates, polyisocyanates having a burette structure, polyisocyanates having a uretdione structure, polyisocyanates having an allophanate structure, and polyisocyanates obtained by reacting a diisocyanate with a trihydric or higher polyhydric alcohol. It is preferable to use the above polyisocyanate from the viewpoint of the weather resistance and durability of the coating film obtained using the aqueous curable composition.

  As the polyisocyanate (A) used in the present invention, in addition to the hydrophobic polyisocyanate, a polyisocyanate having water dispersibility described later and a dispersant having a hydrophilic group but not an isocyanate group are used in combination. Things can also be used.

  The water-dispersible polyisocyanate is a polyisocyanate having a hydrophilic group, and examples of the hydrophilic group include various known and commonly used anionic groups, cationic groups, and nonionic groups. From the viewpoint of water resistance of the cured product obtained from the aqueous curable composition of the present invention, a nonionic group is preferable, and specifically, a polyoxyethylene group is more preferable.

  Examples of the above-described polyisocyanate having water dispersibility include polyethers, polyesters, polyurethanes, vinyl polymers, alkyd resins, fluororesins, and silicone resins having the hydrophilic group and the isocyanate group. Can be used alone or in combination of two or more thereof, but from the viewpoint of water dispersibility of the water dispersible polyisocyanate, it is preferable to use a polyether or vinyl polymer having a hydrophilic group and an isocyanate group.

  Of the polyisocyanates having water dispersibility that can be used in the present invention, polyethers having an isocyanate group and a hydrophilic group will be described.

  The polyether having an isocyanate group and a hydrophilic group can be produced, for example, by reacting a polyether compound having both a hydrophilic group and an active hydrogen-containing group and the hydrophobic polyisocyanate.

  Examples of the polyether compound having both a hydrophilic group and an active hydrogen-containing group include monoalkoxy polyoxyethylene glycol, monoalkoxy polyoxyethylene-polyoxypropylene glycol, polyoxyethylene glycol, polyoxyethylene-poly Examples thereof include hydroxyl group-containing polyethers such as oxypropylene glycol, and these may be used alone or in combination of two or more.

  When producing a polyether having an isocyanate group and a hydrophilic group, an excessive amount of a hydrophobic polyisocyanate is used with respect to the polyether compound having both the hydrophilic group and the active hydrogen-containing group. Thus, a mixture of the polyether having an isocyanate group and a hydrophilic group and a hydrophobic polyisocyanate can be produced by a one-step reaction.

  In addition, it is preferable to introduce a hydrophobic group having 3 or more carbon atoms into the above-described polyether having an isocyanate group and a hydrophilic group, thereby reducing the pot life of the aqueous curable composition of the present invention. It can be made long enough.

  Examples of the hydrophobic group having 3 or more carbon atoms include alkyl groups such as n-propyl group, iso-propyl group, n-butyl group and hexyl group, alicyclic alkyl groups such as cyclopentyl group and cyclohexyl group, An aromatic group such as a phenyl group can be mentioned.

  The method of introducing a hydrophobic group having 3 or more carbon atoms into the polyether having an isocyanate group and a hydrophilic group is, for example, a polyether compound having both the hydrophilic group and an active hydrogen-containing group, a carbon atom Examples thereof include a method of reacting a compound having three or more hydrophobic groups and an active hydrogen-containing group and a hydrophobic polyisocyanate.

  Next, among the polyisocyanates having water dispersibility that can be used in the present invention, a vinyl polymer having an isocyanate group and a hydrophilic group will be described.

  Examples of such vinyl polymers include acrylic polymers, fluoroolefin polymers, vinyl ester polymers, aromatic vinyl polymers, polyolefin polymers, and the like, and the aqueous curable composition of the present invention. When the aqueous resin (B) described later used in the product is an acrylic polymer, an acrylic polymer or a fluoroolefin polymer having an isocyanate group and a hydrophilic group is used from the viewpoint of their compatibility. It is preferable.

  The vinyl polymer having an isocyanate group and a hydrophilic group is, for example, a) a vinyl monomer comprising a vinyl monomer having an isocyanate group and a vinyl monomer having a hydrophilic group. Or (b) obtained by polymerizing a vinyl monomer mixture containing a vinyl monomer having an active hydrogen-containing group and a vinyl monomer having a hydrophilic group. It can be produced by reacting an active hydrogen-containing group of a vinyl polymer obtained with a polyisocyanate.

  Examples of the vinyl monomer having an isocyanate group that can be used in the production method a) include 2-isocyanatopropene, 2-isocyanatoethyl vinyl ether, 2-isocyanatoethyl methacrylate, m-isopropenyl-α, Examples include α-dimethylbenzyl isocyanate, reaction products of polyisocyanate and a vinyl monomer having a hydroxyl group.

  Examples of the vinyl monomer having a hydrophilic group that can be used in the production method a) include alkoxypolyoxy such as methoxypolyethylene glycol (meth) acrylate, butoxypolyethylene glycol (meth) acrylate, methoxypolyoxyethylene vinyl, and the like. Examples thereof include vinyl monomers having an anionic group represented by vinyl monomers having an ethylene group, sodium alkylallylsulfonate, sodium alkylallylphosphate, and the like.

  Examples of the active hydrogen-containing group of the vinyl monomer that can be used in the production method (b) include, for example, hydroxyl group, carboxyl group, phosphoric acid group, phosphorous acid group, sulfonic acid group, sulfinic acid group, mercapto group, silanol group, Examples thereof include an active methylene group, a carbamate group, a ureido group, a carboxylic acid amide group, and a sulfonic acid amide group. Among these, from the viewpoint of easy introduction of the active hydrogen-containing group into the vinyl polymer, a hydroxyl group, an amino group, a carboxyl group, and an active methylene group are preferable, and a hydroxyl group and a carboxyl group are more preferable. One kind of the active hydrogen-containing group may be used alone or two or more kinds may be introduced into the vinyl polymer.

  Examples of the vinyl monomer having an active hydrogen-containing group that can be used in the production method b) include acrylate monomers such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, and 2-hydroxypropyl methacrylate. Moreover, as a vinyl-type monomer which has a hydrophilic group, the thing similar to what can be used by the said manufacturing method a can be used.

  In the production methods a) and b), a vinyl monomer having a hydrophobic group having 4 or more total carbon atoms can be used in combination. By using such a vinyl monomer, the reaction between water-dispersible polyisocyanate and water can be prevented, and the aqueous curable composition of the present invention can have a sufficient pot life. .

  As a method for introducing a hydrophobic group having 4 or more total carbon atoms into a vinyl polymer having an isocyanate group and a hydrophilic group, for example, vinyl having a hydrophobic group having 4 or more total carbon atoms can be used. Examples thereof include a method of copolymerizing a monomer based on another vinyl monomer in the above production method (a) or (b).

  Examples of the vinyl monomer having a hydrophobic group having 4 or more total carbon atoms include n-butyl group, iso-butyl group, tert-butyl group, n-pentyl group, n-hexyl group, An alkyl group having 4 or more carbon atoms such as 2-ethylhexyl group, n-octyl group, n-dodecyl group or n-octadecyl group; cyclopentyl group, cyclohexyl group, cyclooctyl group, dicyclopentanyl group, bornyl group, It has a cycloalkyl group having 4 or more carbon atoms such as an isobornyl group, and specific examples thereof include acrylate monomers such as n-butyl acrylate and n-butyl methacrylate.

  In addition to the various vinyl monomers described above, other vinyl monomers are used in combination with the vinyl polymer having a hydrophilic group and an isocyanate group as long as the object of the present invention is achieved. be able to.

  Examples of the other vinyl monomers include acrylic monomers such as methyl acrylate and methyl methacrylate.

  The weight average molecular weight of the vinyl polymer having an isocyanate group and a hydrophilic group thus obtained is the dispersibility of the resulting water-dispersible polyisocyanate in water, the stability of the isocyanate group in water, and the aqueous curable composition of the present invention. From the viewpoint of curability of the product, 2000-100000 is preferable, and the range of 3000-50000 is more preferable.

  The vinyl polymer having a hydrophilic group and an isocyanate group is preferably used by mixing with the above-described hydrophobic polyisocyanate. In this case, the weight ratio of the vinyl polymer having a hydrophilic group and an isocyanate group to the hydrophobic polyisocyanate (vinyl polymer having a hydrophilic group and an isocyanate group / hydrophobic polyisocyanate) is 0.5 / 9. Within the range of 5 to 7/3 is preferable, within the range of 1/9 to 5/5 is more preferable, and within the range of 2/8 to 4/6 is even more preferable.

  The mixture of the vinyl polymer having a hydrophilic group and an isocyanate group and the hydrophobic polyisocyanate is a one-step reaction by using an excess amount of the hydrophobic polyisocyanate in the production method a) or b). A polyisocyanate (A) that is a mixture of a vinyl polymer having a hydrophilic group and an isocyanate group and a hydrophobic polyisocyanate can be produced.

  Examples of the dispersant having no isocyanate group that can be used in combination with the hydrophobic polyisocyanate as the polyisocyanate (A) but having a hydrophilic group include, for example, vinyl monomers having an isocyanate group among the aforementioned vinyl monomers. And vinyl polymers obtained by using the above-mentioned various vinyl monomers excluding monomers having an active hydrogen-containing group.

  When the water-dispersible polyisocyanate or a dispersant having a hydrophilic group but not having an isocyanate group is used in combination with the hydrophobic polyisocyanate, [(water dispersion having a hydrophilic group and an isocyanate group is used. (Dispersing agent having a hydrophilic polyisocyanate + hydrophilic group but not an isocyanate group) / hydrophobic polyisocyanate] (weight ratio) is preferably in the range of 0.5 / 9.5 to 7/3, The range of 9-5 / 5 is more preferable, and the range of 2 / 8-4 / 6 is still more preferable.

  In addition, the water-dispersible polyisocyanate and hydrophobic polyisocyanate can be used by diluting with an organic solvent inert to the isocyanate group within the range of achieving the object of the present invention.

  Examples of the organic solvent include aliphatic or alicyclic hydrocarbons such as n-hexane, n-heptane, n-octane, cyclohexane, and cyclopentane; aromatic hydrocarbons such as toluene, xylene, and ethylbenzene. Various esters such as ethyl acetate, n-butyl acetate, n-amyl acetate, and ethylene glycol monomethyl ether acetate; various ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl n-amyl ketone, and cyclohexanone;

  Polyalkylene glycol dialkyl ethers such as diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, and dipropylene glycol dimethyl ether; polyalkylene glycol monoalkyl ether acetates such as ethylene glycol methyl ether acetate, propylene glycol methyl ether acetate, and diethylene glycol methyl ether acetate ; Ethers such as 1,2-dimethoxyethane, tetrahydrofuran and dioxane; N-methylpyrrolidone, dimethylformamide, dimethylacetamide, ethylene carbonate and the like can be mentioned, and these can be used alone or in combination of two or more.

  Next, the aqueous resin (B) used in the present invention will be described.

  The aqueous resin (B) used in the present invention has both a primary hydroxyl group and a secondary or higher hydroxyl group, and the hydroxyl value needs to be in the range of 10 to 200. There is a problem that sufficient coating film hardness and water resistance cannot be obtained, and when it exceeds 200, there is a problem that the pot life is reduced. The hydroxyl value is preferably in the range of 20 to 160, more preferably in the range of 20 to 130, from the viewpoint of the hardness, water resistance, and adhesion of the resulting coating film.

  Of the hydroxyl groups possessed by the aqueous resin (B), the primary hydroxyl group / secondary hydroxyl group (molar ratio) must be in the range of 5/95 to 55/45. There are problems such as inadequate coating film hardness and water resistance. Considering the adhesion of the resulting coating film, the primary hydroxyl group / secondary hydroxyl group (molar ratio) is preferably in the range of 10/90 to 50/50.

  When the volume average particle diameter is measured by the light scattering method, the aqueous resin (B) is preferably 10 to 500 nm, and preferably 20 to 300 nm, from the viewpoint of the appearance of the obtained cured product. More preferred.

  The aqueous resin (B) can be dissolved in water or dispersed in water such as a colloidal dispersion or an emulsion.

  Examples of the aqueous resin (B) include a hydroxyl group-containing vinyl acetate resin, styrene-butadiene resin, styrene-acrylonitrile resin, acrylic resin, fluoroolefin resin, silicon-modified vinyl polymer, and polyvinyl alcohol. Vinyl polymers such as: polyester resins, polyurethane resins, phenol resins, melamine resins, epoxy resins, alkyd resins, polyamide resins, polyether resins, silicone resins, and other vinyl polymers Synthetic resins; natural polymers such as animal proteins, starches, cellulose derivatives, dextrins, gum arabic, and the like can be mentioned, and vinyl polymers and various synthetic resins other than vinyl polymers are preferred.

  Among the aqueous resins (B), the vinyl polymer having a hydroxyl group is within the range of the hydroxyl value and the molar ratio of (primary hydroxyl group / secondary hydroxyl group). It can be produced by copolymerizing a monomer and other vinyl monomers.

  Among the vinyl monomers having a hydroxyl group, examples of vinyl monomers capable of introducing a primary hydroxyl group into the resulting vinyl polymer having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 4 -Hydroxybutyl acrylate. Moreover, as a vinyl monomer which can introduce | transduce a secondary hydroxyl group into the vinyl polymer which has the said hydroxyl group, 2-hydroxypropyl (meth) acrylate is mentioned, for example.

  Examples of the other vinyl monomers include acrylic monomers such as methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, cyclohexyl (meth) acrylate, and acrylamide. It is done.

  The vinyl polymer having a hydroxyl group can be produced, for example, by radical polymerization or redox polymerization of the various vinyl monomers described above.

  The radical polymerization described above is roughly classified into an emulsion polymerization method using water as a solvent and a solution polymerization method using an organic solvent as a solvent, and both methods can be applied.

  The solution polymerization method is a method in which the various vinyl monomers and initiators described above are added to an organic solvent and copolymerized, and then the aqueous solvent ( B) can be produced.

  As such an organic solvent, for example, the same organic solvent that can be used when diluting the water-dispersible polyisocyanate can be used.

  Examples of the initiator include 2,2′-azobis (isobutyronitrile), 2,2′-azobis (2,4-dimethylbutyronitrile), and 2,2′-azobis (2-methylbutyronitrile). Various azo compounds such as tert-butyl peroxypivalate, tert-butyl peroxybenzoate, tert-butyl peroxy-2-ethylhexanoate, di-tert-butyl peroxide, cumene hydroper Examples include various peroxides such as oxide or diisopropyl peroxycarbonate.

  The emulsion polymerization method using water as a solvent is a method in which various vinyl monomers and various known and conventional emulsifiers are added to water and copolymerized. Examples of the emulsifier that can be used at this time include nonionic emulsifiers, anionic emulsifiers, cationic emulsifiers, and reactive emulsifiers. Two or more of the above emulsifiers can be used in combination.

  The aforementioned emulsifier may be used in an amount of less than 10 parts by weight with respect to 100 parts by weight of the total vinyl monomer used from the viewpoint of the water resistance of the coating film obtained using the aqueous curable composition of the present invention. It is preferable to use less than 5 parts by weight.

  In the emulsion polymerization method, the vinyl monomer can be redox polymerized by using a reducing agent to obtain an aqueous resin (B).

  Moreover, as the vinyl polymer having a hydroxyl group, those having a carboxyl group are preferable. For example, the hydroxyl group described above for a vinyl monomer having a carboxyl group such as acrylic acid, methacrylic acid, and maleic acid is used. A carboxyl group can be introduced into the vinyl polymer by being copolymerized with the vinyl monomer or the like. In addition, the carboxyl group at this time may be partly or wholly neutralized with a basic compound described later to form a carboxylate.

  Examples of such basic compounds include amines such as triethylamine, dimethylethanolamine, and ammonia; alkali metals such as sodium hydroxide and potassium hydroxide.

  The polyester resin having a hydroxyl group can be obtained by reacting an acid component mainly composed of aromatic dicarboxylic acid or aliphatic dicarboxylic acid and an alcohol component mainly composed of dialcohol.

  Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid or their lower alkyl esters, acid anhydrides, and the like, and one or more of these can be used. Examples of the aliphatic dicarboxylic acid include adipic acid, sebacic acid, azelaic acid, succinic acid, fumaric acid, maleic acid, hymic acid, 1,6-cyclohexanedicarboxylic acid and the like, or lower alkyl esters of these dicarboxylic acids, An acid anhydride or the like may be used. These may be used alone or in combination of two or more.

  As the acid component, in addition to the dicarboxylic acid, a small amount of monocarboxylic acid or trivalent or higher carboxylic acid may be used. Examples of the monocarboxylic acid include p-t-butylbenzoic acid, and examples of the trivalent or higher carboxylic acid include trimellitic acid, pyromellitic acid, trimesic acid, methylcyclohexericarboxylic acid, and acids of these acids. An anhydride etc. can be mentioned.

  Examples of dialcohols that can be used in the polyester resin include ethylene glycol, propylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, and neopentyl glycol. 1,5-pentanediol, 1,6-hexanediol, 3-methylpentanediol, diethylene glycol, 1,4-cyclohexanedimethanol, 3-methyl-1,5-pentanediol, 2-methyl-1,3- Propanediol, 2,2-diethyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, xylylene glycol or hydrogenated bisphenol A, and ethylene oxide or propylene oxide addition of bisphenol A Things etc. It may be used alone or as a mixture of more than two.

  As the alcohol component, trivalent or higher alcohols can be used in addition to the dialcohol, and examples include trimethylolethane, trimethylolpropane, glycerin, pentaerythritol and the like.

  A part of the acid component and alcohol component may be replaced with oxyacid components such as dimethylolpropionic acid, oxypivalic acid, paraoxybenzoic acid and the like, lower alkyl esters of these acids; and lactones such as ε-caprolactone. The polyester resin can be produced by a conventionally known esterification reaction or ester conversion reaction using the acid component, the alcohol component, and, if necessary, the oxyacid component.

  Examples of the epoxy resin having a hydroxyl group include a bisphenol-type epoxy resin, a novolac-type epoxy resin; and a modified epoxy resin in which various modifiers are reacted with an epoxy group or a hydroxyl group in these epoxy resins. In the production of the modified epoxy resin, the modification time with the modifier is not particularly limited, and it may be modified in the middle of the epoxy resin production or in the final stage of the epoxy resin production.

  The bisphenol type epoxy resin is, for example, a resin obtained by condensing epichlorohydrin and bisphenol up to a high molecular weight in the presence of a catalyst such as an alkali catalyst, if necessary, epichlorohydrin and bisphenol, an alkali catalyst if necessary, etc. In the presence of the catalyst, any of resins obtained by condensation to give a low molecular weight epoxy resin and a polyaddition reaction of the low molecular weight epoxy resin and bisphenol may be used.

  Examples of the bisphenol include bis (4-hydroxyphenyl) methane [bisphenol F], 1,1-bis (4-hydroxyphenyl) ethane, 2,2-bis (4-hydroxyphenyl) propane [bisphenol A], 2,2-bis (4-hydroxyphenyl) butane [bisphenol B], bis (4-hydroxyphenyl) -1,1-isobutane, bis (4-hydroxy-tert-butyl-phenyl) -2,2-propane, and p- (4-hydroxyphenyl) phenol, oxybis (4-hydroxyphenyl), sulfonylbis (4-hydroxyphenyl), 4,4′-dihydroxybenzophenone, bis (2-hydroxynaphthyl) methane, and the like. Of these, bisphenol A and bisphenol F are preferred. It is use. The bisphenols can be used alone or as a mixture of two or more.

  Examples of commercially available bisphenol-type epoxy resins include Epicoat 828, 812, 815, 820, 834, 1001, 1004, 1007, 1009, and 1010 manufactured by Yuka Shell Epoxy Corporation; Examples include Araldite AER 6099 manufactured by Asahi Ciba; and Epomic R-309 manufactured by Mitsui Chemicals.

  Examples of the novolak type epoxy resin that can be used as the epoxy resin include various novolak type epoxy resins such as a phenol novolak type epoxy resin, a cresol novolak type epoxy resin, and a phenol glyoxal type epoxy resin having a large number of epoxy groups in the molecule. Resins can be mentioned.

  As the modified epoxy resin, for example, an epoxy ester resin obtained by reacting a dry oil fatty acid with the bisphenol type epoxy resin or novolak type epoxy resin; and a polymerizable unsaturated monomer component containing acrylic acid or methacrylic acid is reacted. Epoxy acrylate resin; Urethane modified epoxy resin reacted with isocyanate compound; Amino group or quaternary ammonium by reacting amine compound with epoxy group in bisphenol type epoxy resin, novolac type epoxy resin or various modified epoxy resins Examples thereof include an amine-modified epoxy resin into which a salt is introduced.

  Next, the aqueous curable composition of the present invention will be described.

  The aqueous curable composition of the present invention contains the above-described polyisocyanate (A) and the above-mentioned aqueous resin (B), and includes those obtained by dissolving or dispersing them in water. Examples of the method of mixing them include a method of adding an aqueous dispersion of polyisocyanate (A) to an aqueous solution or aqueous dispersion of the aqueous resin (B) and stirring. As a stirring method, for example, there is a method using various known and conventional stirrers, and if it is a small amount, it can be easily and uniformly mixed by simple stirring using a stirring rod or the like. It is preferable to use various known and conventional stirrers because a large amount of the aqueous curable composition can be prepared in a short time. Moreover, when using hydrophobic polyisocyanate for polyisocyanate (A), it is preferable to use well-known and usual various stirrers which have strong shearing force, such as a jet mill, for example.

  The mixing ratio of the polyisocyanate (A) and the aqueous resin (B) at this time is (polyisocyanate (A) from the viewpoint of the curability of the aqueous curable composition of the present invention and the performance of the cured product obtained from the composition. ) Is preferably 0.1 to 5, more preferably 0.3 to 3, and more preferably 0.5 to 3. 2 is more preferable.

  The aqueous curable composition thus obtained includes paints, adhesives, inks, waterproofing materials, sealing agents, various fibers such as natural fibers, synthetic fibers, and glass fibers, and paper impregnation agents, natural fibers, synthetic fibers, and glass. Although it can be used for various applications such as various fibers such as fibers and a surface treatment agent for paper, it is particularly preferable to use as a water-based paint or a water-based adhesive.

  When the aqueous curable composition is used as an aqueous coating, it has excellent adhesion to a base material or plastic base material having a highly hydrophobic old coating film, has a long usable time, and further has an appearance such as transparency and gloss, A cured coating film excellent in water resistance, solvent resistance and the like can be obtained. At this time, it can be used as a clear paint containing no pigment, or it can be used as a colored paint by blending various known organic or inorganic pigments.

  The water-based paint has a long usable life, and can penetrate into a high-density inorganic base material that has been difficult to penetrate with conventional water-based paints to form a cured coating film. Since this cured coating film has a function of effectively protecting the substrate and also has good adhesion to the top coating film, it can be used as a high-performance undercoating paint. Further, the water-based paint is not limited to the undercoat paint, but can be used as an overcoat paint for various substrates.

  When the aqueous curable composition is used as an aqueous adhesive, it has excellent performance such as excellent adhesion to a substrate having a highly hydrophobic old coating film or a plastic substrate, a long pot life, and high adhesive strength. Can be obtained.

  In the aqueous curable composition of the present invention, additives suitable for various applications, for example, a filler, a leveling agent, a thickener, an antifoaming agent, an organic solvent, an ultraviolet absorber, and an antioxidant, are optionally added. Alternatively, various known and commonly used additives such as a pigment dispersant can also be blended.

  As the base material to which the water-based paint and water-based adhesive of the present invention can be applied, various known and usual ones can be used. For example, various metal base materials, inorganic base materials, plastic base materials, paper, synthetic fibers, natural materials Examples include inorganic fibers such as fibers and glass fibers, cloth, synthetic leather, natural leather, and wood-based base materials. The water-based paint and water-based adhesive of the present invention have a plastic base material and an old coating film more than conventional ones. It has excellent adhesion to a highly hydrophobic material such as a substrate.

  Among such various substrates, representative examples of metal substrates include metals such as iron, nickel, aluminum, chromium, zinc, tin, copper, and lead; various metals listed above such as stainless steel and brass. Alloys: Various metals or alloys as described above, and various surface-treated metals that have been plated or chemically treated.

  Examples of the inorganic base material include a cured product produced from a calcium compound such as calcium silicate, calcium aluminate, calcium sulfate, and calcium oxide; a ceramic obtained by sintering a metal oxide such as alumina, silica, and zirconia; Tiles obtained by firing various clay minerals; various glasses and the like. Typical examples of hardened bodies produced from calcium compounds include hardened cement compositions such as concrete and mortar, asbestos slate, lightweight aerated concrete (ALC) hardened bodies, dolomite plaster hardened bodies, and plaster plaster hardened. Body, calcium silicate plate and the like.

  Examples of the plastic substrate include molded articles of thermoplastic resins such as polystyrene, polycarbonate, polymethyl methacrylate, ABS resin, polyphenylene oxide, polyurethane, polyethylene, polyvinyl chloride, polypropylene, polybutylene terephthalate or polyethylene terephthalate; Examples thereof include molded products of various thermosetting resins such as polyester resins, phenol resins, cross-linked polyurethanes, cross-linked acrylic resins or cross-linked saturated polyester resins.

  In addition, the above-described base material is a base material that has been previously coated, or a base material that has been coated, and in which the degradation of the coated portion has progressed. Can be used.

  These various base materials are used in various shapes such as a plate shape, a spherical shape, a film shape, a sheet shape, a large structure, a complex shape assembly, and the like, depending on applications. There is no.

  Examples of the method for applying the water-based paint of the present invention to the substrate described above include known and commonly used coating methods such as brush coating, roller coating, spray coating, dip coating, flow coater coating, roll coater coating, and the like. Next, it is allowed to stand at room temperature for about 1 to 10 days, or is heated for about 30 seconds to about 2 hours in a temperature range of about 40 to about 250 ° C., so that it has excellent appearance and water resistance. A film can be obtained.

  In addition, as a method of applying the aqueous adhesive of the present invention to the substrate, for example, a known and commonly used method such as a spatula, a brush, a spray, a roll, or the like is applied to at least one of the same type of substrate or a different type of substrate. Then, it is allowed to stand at room temperature for about 1 to 10 days, heated at a temperature range of about 40 to about 150 ° C. for about 5 seconds to about 2 hours, or pressurized as necessary. Excellent adhesive strength can be obtained.

Next, the present invention will be described in detail with reference examples, examples and comparative examples, but the present invention is not limited thereto. All parts and% in the text are based on weight unless otherwise specified.
First, although an aqueous curable composition is demonstrated by an Example and a comparative example, the polyisocyanate used by an Example and a comparative example is demonstrated first.

Hydrophobic polyisocyanate (A-1)
Hexamethylene diisocyanate-based isocyanurate-type polyisocyanate “Bernock DN-980S” (Dainippon Ink & Chemicals, Inc. isocyanate group content (hereinafter abbreviated as NCO group content) 21%, average NCO functional group number About 3.6, non-volatile content 100%]

Reference example 1 [Preparation example of polyisocyanate composition (A-2) having water dispersibility]
In a four-necked flask equipped with a stirrer, a thermometer, a cooling tube, and a nitrogen introduction tube, 200 parts of diethylene glycol diethyl ether (hereinafter abbreviated as DEDG) was charged and heated to 110 ° C. under a nitrogen stream. Methoxy polyethylene glycol methacrylate (containing 9 average oxyethylene units per molecule) 100 parts, methyl methacrylate (hereinafter abbreviated as MMA) 60 parts, 2-hydroxyethyl methacrylate (hereinafter abbreviated as 2-HEMA) 10 parts, 30 parts of cyclohexyl methacrylate (hereinafter abbreviated as CHMA), 5 parts of t-butylperoxy-2-ethylhexanoate, and 1 part of t-butylperoxybenzoate are dropped over 5 hours. did. After the dropwise addition, the mixture was reacted at 110 ° C. for 9 hours to obtain an acrylic polymer solution having a nonvolatile content of 50%. Next, 600 parts of hydrophobic polyisocyanate (A-1) was added, the temperature was raised to 95 ° C., and the mixture was reacted at the same temperature for 6 hours. The water dispersibility was such that the non-volatile content was 80% and the NCO group content was 12%. A polyisocyanate composition (A-2) was obtained.

Reference Example 2 [Preparation Example of Polyisocyanate Composition (A-3) Having Water Dispersibility]
In a reactor similar to Reference Example 1, 200 parts of DEDG, 143 parts of methoxypolyethylene glycol (molecular weight: 400), and 657 parts of hydrophobic polyisocyanate (A-1) were charged, and the temperature was raised to 95 ° C. over 30 minutes. The polyisocyanate composition (A-3) having a water dispersibility modified with methoxypolyethylene glycol having a nonvolatile content of 80% and an NCO group content of 12% was obtained by reacting at 95 ° C. for 6 hours.

Reference Example 3 [Preparation Example of Aqueous Resin Emulsion (C-1)]
5 parts “Hytenol N-08” (anionic emulsifier manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), “Emulgen 931” (nonionic emulsifier manufactured by Kao Corp.) 5 parts in the same reactor as in Reference Example 1 Then, 270 parts of deionized water was charged and heated to 80 ° C. under a nitrogen stream, and then an aqueous solution in which 0.8 part of ammonium persulfate was dissolved in 16 parts of deionized water was added. Furthermore, 80 parts of butyl acrylate (hereinafter abbreviated as BA), 87 parts of MMA, 4 parts of acrylic acid (hereinafter abbreviated as AA), 14 parts of 2-HEMA, 2-hydroxypropyl methacrylate (hereinafter referred to as 2-hydroxypropyl methacrylate) Abbreviated as HPMA.) A mixed solution of 15 parts was added dropwise over 3 hours. After dropping, the mixture was reacted for 2 hours, then cooled to 25 ° C., neutralized with 1.5 parts of 28% aqueous ammonia, 43% non-volatile content, average particle size 120 nm, solid content hydroxyl value 60 mg KOH / g, (aqueous resin A hydroxyl group-containing acrylic resin emulsion (C-1) was obtained: (primary hydroxyl group in the middle) / (secondary hydroxyl group in the aqueous resin) = 50/50 (molar ratio). In addition, “average particle diameter” in this example is a volume average particle diameter measured by a light scattering method using MICROTRAC 9340-UPA manufactured by Nikkiso Co., Ltd. The particle size was measured at 25 ° C. using 199 g of ion-exchanged water added to 1 g of the aqueous resin emulsion and well mixed with a stirring bar.

Reference Example 4 [Preparation Example of Aqueous Resin Dispersion (C-2)]
After charging 60 parts of DEDG into the same reactor as in Reference Example 1 and raising the temperature to 125 ° C. under a nitrogen stream, 80 parts of BA, 87 parts of MMA, 4 parts of AA, 6 parts of 2-HEMA, 13 parts of 2-HPMA A mixed solution consisting of 20 parts of t-butylperoxy-2-ethylhexanoate and 1 part of t-butylperoxybenzoate was added dropwise over 5 hours. After dropping, the mixture was reacted at 125 ° C. for 5 hours, then cooled to 60 ° C., 5.6 parts of triethylamine was added, and the mixture was mixed at 60 ° C. for 30 minutes. Then, after 461 parts of ion-exchanged water was added dropwise over 2 hours, the mixture was cooled to 25 ° C., non-volatile content 30%, average particle diameter 150 nm, solid content hydroxyl value 35 mgKOH / g, (primary hydroxyl group in aqueous resin) / A hydroxyl group-containing acrylic resin dispersion (C-2) of (secondary hydroxyl group in aqueous resin) = 33/67 (molar ratio) was obtained.

Reference Example 5 [Preparation Example of Aqueous Resin Emulsion (C-3)]
5 parts “Hytenol N-08” (anionic emulsifier manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), “Emulgen 931” (nonionic emulsifier manufactured by Kao Corp.) 5 parts in the same reactor as in Reference Example 1 Then, 270 parts of deionized water was charged and heated to 80 ° C. under a nitrogen stream, and then an aqueous solution in which 0.8 part of ammonium persulfate was dissolved in 16 parts of deionized water was added. Further, a mixed solution comprising 80 parts of butyl acrylate (hereinafter abbreviated as BA), 65 parts of MMA, 4 parts of acrylic acid (hereinafter abbreviated as AA), 5 parts of 2-HEMA, and 46 parts of 2-HPMA. It was dripped over 3 hours. After dropping, the mixture was reacted for 2 hours, then cooled to 25 ° C., neutralized with 1.5 parts of 28% aqueous ammonia, 43% non-volatile content, average particle size 100 nm, solid content hydroxyl value 100 mg KOH / g (in aqueous resin) Primary hydroxyl group) / (secondary hydroxyl group in aqueous resin) = 10/90 (molar ratio) to obtain a hydroxyl group-containing acrylic resin emulsion (C-3).

Reference Example 6 [Preparation Example of Aqueous Resin Water Dispersion (C-4)]
In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser with a dehydration trap and a nitrogen introduction tube, 309 parts of phthalic anhydride, 142 parts of tetrahydrophthalic anhydride, 71 parts of neopentyl glycol, 277 parts of 1,6-hexanediol, Trimethylolpropane (67 parts) and dibutyltin oxide (0.3 parts) were charged, the temperature was raised to 220 ° C. with stirring, and a dehydration condensation reaction was performed until the acid value reached 13 mgKOH / g. Next, the temperature was lowered to 100 ° C., 134 parts of methoxypolyethyleneglycol glycidyl ether (average molecular weight: 250) was added, and the temperature was raised to 160 ° C. and reacted for 2 hours. Furthermore, after adding 100 parts of DEDG and stirring uniformly, internal temperature was lowered | hung to 80 degreeC, 16 parts of dimethylethanolamine was added, and it stirred and mixed for 1 hour. Subsequently, 1380 parts of ion-exchanged water was added dropwise over 1 hour, the nonvolatile content was 40%, the average particle size was 80 nm, the solid content acid value was 12 mgKOH / g, the solid content hydroxyl value was 95 mgKOH / g (primary hydroxyl group in the aqueous resin) / A hydroxyl group-containing polyester resin aqueous dispersion (C-4) in which (secondary hydroxyl group in the aqueous resin) = 50/50 (molar ratio) was obtained.

Comparative Reference Example 1 [Preparation example of comparative aqueous resin emulsion (RC-1)]
5 parts “Hytenol N-08” (anionic emulsifier manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), “Emulgen 931” (nonionic emulsifier manufactured by Kao Corp.) 5 parts in the same reactor as in Reference Example 1 Then, 270 parts of deionized water was charged and heated to 80 ° C. under a nitrogen stream, and then an aqueous solution in which 0.8 part of ammonium persulfate was dissolved in 16 parts of deionized water was added. Further, a mixed solution consisting of 85 parts of BA, 83 parts of MMA, 4 parts of AA, and 28 parts of 2-HEMA was added dropwise over 3 hours. After dropping, the mixture was reacted for 2 hours, then cooled to 25 ° C., neutralized with 1.5 parts of 28% aqueous ammonia, a primary hydroxyl group having a nonvolatile content of 43%, an average particle size of 110 nm, and a solid content hydroxyl value of 60 mgKOH / g. An acrylic resin emulsion for comparison (RC-1) containing only styrene was obtained.

Comparative Reference Example 2 [Preparation Example of Comparative Water Resin Emulsion (RC-2)]
5 parts “Hytenol N-08” (anionic emulsifier manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), “Emulgen 931” (nonionic emulsifier manufactured by Kao Corp.) 5 parts in the same reactor as in Reference Example 1 Then, 270 parts of deionized water was charged and heated to 80 ° C. under a nitrogen stream, and then an aqueous solution in which 0.8 part of ammonium persulfate was dissolved in 16 parts of deionized water was added. Further, a mixed solution consisting of 85 parts of BA, 80 parts of MMA, 4 parts of AA, and 31 parts of 2-HEMA was added dropwise over 3 hours. After dropping, the mixture was reacted for 2 hours, then cooled to 25 ° C., neutralized with 1.5 parts of 28% aqueous ammonia, a secondary component having a nonvolatile content of 43%, an average particle size of 120 nm, and a solid content hydroxyl value of 60 mgKOH / g. A comparative acrylic resin emulsion (RC-2) containing only hydroxyl groups was obtained.

Comparative Reference Example 3 [Preparation example of comparative aqueous resin water dispersion (RC-3)]
In the same reaction vessel as in Reference Example 4, 369 parts of phthalic anhydride, 162 parts of tetrahydrophthalic anhydride, 82 parts of neopentyl glycol, 309 parts of 1,6-hexanediol, 78 parts of trimethylolpropane, dibutyltin oxide 0.3 The temperature was raised to 220 ° C. with stirring, and a dehydration condensation reaction was performed until the acid value reached 15 mgKOH / g. Next, the temperature was lowered to 160 ° C., 100 parts of DEDG was added and stirred uniformly, then the internal temperature was lowered to 80 ° C., 19 parts of dimethylethanolamine was added, and the mixture was stirred and mixed for 1 hour. Subsequently, 1380 parts of ion-exchanged water was added dropwise over 1 hour, and a comparative hydroxyl group containing only primary hydroxyl groups having a nonvolatile content of 40%, an average particle size of 100 nm, a solid content acid value of 15 mgKOH / g, and a solid content hydroxyl value of 95 mgKOH / g. An aqueous polyester resin dispersion (RC-3) was obtained.

Example 1
The polyisocyanate composition (A-2) having water dispersibility and the hydroxyl group-containing acrylic resin emulsion (C-1) are represented by [isocyanate group / (C of polyisocyanate composition having water dispersibility (A-2)]. -1) 50 parts of a polyisocyanate composition (A-2) having water dispersibility and a hydroxyl group-containing acrylic resin emulsion so that the molar ratio of the hydroxyl group of the hydroxyl group-containing acrylic resin in the composition is 1.2 / 1. An aqueous curable composition was prepared by mixing 500 parts of (C-1). Hereinafter, this is abbreviated as an aqueous curable composition (D-1). The obtained aqueous curable composition (D-1) was applied on a glass plate, an ABS plate, and a zinc plate using an applicator so that the dry coating film became 60 μm immediately after preparation, and the temperature was 20 ° C. and humidity. The film was dried for 1 week under the condition of 60% RH to prepare a cured coating film. About the obtained cured coating film, hardness, adhesiveness, and water resistance were evaluated. The evaluation results are shown in Table 1.

Examples 2-5
As shown in Table 1, various polyisocyanate compositions were used in place of the water-dispersible polyisocyanate composition (A-2) used in Example 1. Further, in place of the hydroxyl group-containing acrylic resin emulsion (C-1) used in Example 1, various aqueous resins were used, and [the isocyanate group of the polyisocyanate having water dispersibility / the hydroxyl group of the aqueous resin] ] The polyisocyanate of the quantity described in the same table was mixed so that the molar ratio of 1.2 / 1 may be mixed, and the aqueous curable composition was prepared. Hereinafter, the composition thus obtained is abbreviated as aqueous curable compositions (D-2) to (D-5). Each aqueous curable composition thus obtained was coated on a glass plate, ABS plate, and zinc plate immediately after preparation in the same manner as in Example 1, and dried for 1 week under conditions of a temperature of 20 ° C. and a humidity of 60% RH. At least, a cured coating film was prepared. About these, evaluation similar to Example 1 was performed. The evaluation results are shown in Table 1.

Comparative Examples 1-3
500 parts of (RC-1) or (RC-2) is used as the aqueous resin, so that the molar ratio of isocyanate groups / hydroxy groups in (RC-1) or (RC-2) is 1.2 / 1. The curable compositions (RD-1) to (RD-3) for comparative evaluation were prepared by mixing the polyisocyanate compositions in the amounts shown in Table 3. In the same manner as in Example 1, immediately after preparation, a cured coating film was prepared by coating and drying on a glass plate, an ABS plate, and a zinc plate. About these, evaluation similar to Example 1 was performed. The evaluation results are shown in Tables (1) and (2).

<< Footnotes in Table 1 >>
Each numerical value indicating the use ratio of the raw materials is assumed to be in parts by weight.

1) “Hardness”:
About the dry coating film created on the glass plate, it measured and evaluated with the Koenig hardness meter on the conditions of temperature 20 degreeC and humidity 60%.

2) “Adhesiveness”:
Using a cutter knife, cuts with a spacing of 2 mm were made vertically and horizontally so that 25 2 mm square grids were formed on the coating film prepared on the test plate. Subsequently, the cellophane adhesive tape was peeled off after being brought into close contact with the grid, and evaluated by the residual ratio, which is the ratio of the coating film remaining on the test plate. Evaluation was performed according to the following evaluation criteria and the residual rate.

Evaluation criteria for adhesion ◎: Residual rate = 90% or more ○: Residual rate = 70 to 90%
Δ: Residual rate = 50 to 70%
X: Residual rate = 50% or less

Residual rate of coating film [%] = (Area of coating film remaining after peeling / Area of coating film on grid before peeling) × 100

3) “Water resistance”:
The coating film prepared on the glass plate was immersed in deionized water at 20 ° C. for 24 hours, and the appearance of the coating film was evaluated. The evaluation criteria at that time are as follows.

Evaluation criteria for whitening of coating film ◎: No change at all ○: Very slight whitening △: Fair whitening ×: Extremely whitening

Criteria for coating film swelling ◎: No change ○: Slight swelling occurs △: Swelling occurs significantly ×: Swelling occurs significantly

Reference Example 5 [Preparation Example of Paint Main Component (E-1)]
Deionized water 72.9 parts, "Orotan SG-1" (pigment dispersant manufactured by Rohm & Haas, USA) 6.7 parts, 10% aqueous solution of sodium tripolyphosphate 4.9 parts, "Neugen EA-120" [ Daiichi Kogyo Seiyaku Co., Ltd. wetting agent] 2.2 parts, ethylene glycol 18.0 parts, “Best Side 1087T” [Dai Nippon Ink Chemical Co., Ltd. preservative] 1.0 part, ammonia water (28%) 0.5 parts, “Titanics JR-600A” (Titanium Co., Ltd. titanium oxide) 249.2 parts and “SN deformer 121” (San Nopco antifoaming agent) 0.8 The part mixture was dispersed with a disper for about 1 hour. To this, 607.0 parts of an aqueous resin (C-1), “Texanol” (a film-forming aid manufactured by Eastman Chemical, USA), 38.2 parts, “Primal QR-708” (an increase manufactured by Rohm & Haas, Inc.) Viscosity] 10% aqueous solution 1.2 parts, “BYK-028” (antifoam manufactured by BYK Chemie) 0.2 part was added and stirred, the pigment weight concentration was 48%, and the non-volatile content was 52.5. % Paint main ingredient component (E-1) was obtained.

Reference Example 6 [Preparation Example of Paint Main Component (E-2)]
A paint main ingredient component (E-2) was obtained in the same manner as in the preparation example of Reference Example 5 except that the aqueous resin (C-3) was used instead of the aqueous resin (C-1).

Comparative Reference Example 7 [Preparation Example of Comparative Paint Main Component (RE-1)]
A comparative paint main ingredient component (RE-1) was obtained in the same manner except that the aqueous resin (RC-1) was used in place of the aqueous resin (C-1) in the preparation example of Reference Example 5.

Comparative Reference Example 8 [Preparation Example of Comparative Paint Main Component (RE-2)]
A comparative paint main ingredient component (RE-2) was obtained in the same manner as in Reference Example 5 except that the aqueous resin (RC-2) was used instead of the aqueous resin (C-1).

Reference Examples 7 to 8 [Preparation examples of water-based paints (F-1) to (F-2)]
Various water-based paints were prepared by mixing the paint main component (E-1), (E-2) and each polyisocyanate in the ratios described in Table 2. In Examples 6 and 7, the molar ratio of (isocyanate group possessed by polyisocyanate / hydroxyl group possessed by aqueous resin) was 1.5 / 1. Hereinafter, the obtained white paint is abbreviated as water-based paints (F-1) to (F-2).

Reference Example 9 [Formation of old paint film]
A coating film was formed on an aluminum plate by an air spray method so that the dry film thickness of the water-based paint (F-1) obtained in Reference Example 7 was 70 μm immediately after preparation. Subsequently, it was dried for 1 week in an atmosphere of a temperature of 20 ° C. and a humidity of 60% RH. Further, each of the obtained cured coating films was forcibly deteriorated for one month in an atmosphere of 40 ° C. and a humidity of 60% to prepare an old coating film.

Examples 6 to 7 [Adhesion test to old paint film]
Water-based paints (F-1) and (F-2) were spray-coated on the old paint film prepared in Reference Example 9 so as to have a dry film thickness of 70 μm, respectively. Subsequently, it was dried for 1 week in an atmosphere of a temperature of 20 ° C. and a humidity of 60% RH. The coating hardness and adhesion of each of the resulting cured coatings were evaluated.

Comparative Examples 4 to 5 [Preparation examples of water-based paints (RF-1) to (RF-2)]
Various water-based paints were prepared by mixing the paint main component (RE-1), (RE-2) and each polyisocyanate at the ratios described in Table 2. The molar ratio of (isocyanate group of polyisocyanate / hydroxyl group of aqueous resin) was 1.5 / 1. The obtained white paint is hereinafter abbreviated as aqueous paint (RF-1) to (RF-2).

  The obtained comparative water-based paints (RF-1) to (RF-2) were sprayed on the old coating film prepared in Reference Example 9 so as to have a dry film thickness of 70 μm, as in Examples 6 and 7. It was painted and dried for 1 week in an atmosphere of temperature 20 ° C. and humidity 60% RH. The coating hardness and adhesion of each of the cured coatings obtained were evaluated. The evaluation results are shown in Table 2.

<< Footnotes in Table 2 >>
Each numerical value indicating the use ratio of the raw materials is assumed to be in parts by weight.

  Adhesion was evaluated based on the same evaluation criteria as in Table 1.

Claims (8)

A polyisocyanate (A) and an aqueous resin (B) are contained, and the aqueous resin (B) has a hydroxyl value of 10 to 200, and the aqueous resin (B) has a primary hydroxyl group and 2 A water-based curable composition having a molar ratio of primary or higher hydroxyl group (primary hydroxyl group / secondary or higher hydroxyl group) of 5/95 to 55/45. The aqueous curable composition according to claim 1, wherein the polyisocyanate (A) has water dispersibility. The aqueous curable composition according to claim 1 or 2, wherein a molar ratio of [isocyanate group of the polyisocyanate (A) / hydroxyl group of the aqueous resin (B)] is 0.5 to 3.0. The aqueous curable composition according to any one of claims 1 to 3, wherein the aqueous resin (B) is obtained using a vinyl polymer. The aqueous curable composition according to any one of claims 1 to 4, wherein the polyisocyanate (A) is an aliphatic polyisocyanate. The aqueous curable composition according to any one of claims 1 to 5, wherein the polyisocyanate (A) has, on average, a polyoxyethylene group composed of 3 or more oxyethylenes. An aqueous paint comprising the aqueous curable composition according to claim 1. An aqueous adhesive comprising the aqueous curable composition according to claim 1.