Aqueous polyurethane resin composition and coating material using said composition

Abstract

An aqueous polyurethane resin composition is provided that exhibits excellent finished appearance and excellent impact resistance (e.g., chipping resistance) and adhesion. The aqueous polyurethane resin composition comprises at least (a) at least two different organic diisocyanate compounds and / or polyisocyanate compounds; (b) a polyol compound; (c) an acidic group-containing compound containing at least two compounds, the compounds being a compound containing a carboxyl group as an acid group (a carboxyl group-containing compound) and a compound containing a sulfo group as an acid group (a sulfo group-containing compound); and (d) a chain extender of a polyamine compound, a diamine compound, a polyol compound, and / or an alkanolamine compound having a molecular weight of 400 or less. The aqueous polyurethane resin composition has a viscosity of 500 Pa·s or more and 50,000 Pa·s or less when the polyurethane resin is present in an amount of 65% by weight.

Description

[Technical Field]

[0001] The present invention relates to an aqueous polyurethane resin composition that has excellent finished appearance, as well as excellent impact resistance such as chipping resistance and / or adhesion, and to a paint composition, coating composition, ink composition, or adhesive composition that contains the aqueous polyurethane resin composition. [Background technology]

[0002] Aqueous polyurethane resin compositions have excellent adhesion to substrates, abrasion resistance, impact resistance, solvent resistance, etc., and are therefore widely used as paints, inks, adhesives, and various coating agents for paper, plastics, films, metals, rubber, elastomers, textile products, etc. (Patent Documents 1 to 3). When using aqueous polyurethane resin compositions for mono-coating or multi-layer coating on electrodeposition-coated metal substrates, it is particularly necessary to continuously improve the finished appearance, impact resistance, and adhesion. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JPH08-209066A [Patent Document 2] JPH07-166093A [Patent Document 3] JP2004-97917A Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide an aqueous polyurethane resin composition that has an excellent finished appearance, and further has excellent impact resistance, such as chipping resistance, and adhesion. [Means for solving the problem]

[0005] As a result of extensive research, the present inventors have found that, in an aqueous polyurethane resin composition containing a polyurethane resin obtained from components including: (a) at least two different organic diisocyanate compounds and / or polyisocyanate compounds; (b) a polyol compound; (c) an acidic group-containing compound consisting of at least two compounds, namely, a compound containing a carboxyl group as an acid group (a carboxyl group-containing compound) and a compound containing a sulfo group as an acid group (a sulfo group-containing compound); and (d) a chain extender having a molecular weight of 400 or less, selected from the group consisting of polyamine compounds, diamine compounds, polyol compounds, and alkanolamine compounds, when the polyurethane resin is contained in an amount of 65 wt %, the aqueous polyurethane resin composition has a viscosity of 500 Pa s or more and 50,000 Pa s or less, and therefore has excellent flow properties obtained by controlling the resin viscosity, even when the water evaporates after application and the resin particles fuse and solidify (solid content: 65%). The present inventors have also found that by adjusting the components of the aqueous polyurethane resin composition, it is possible to provide a coating film that has both excellent adhesion to an electrodeposited film and excellent impact resistance, such as chipping resistance. Thus, the present inventors have achieved the present invention.

[0006] The present invention provides the following solutions.

[0007] [1] At least the following components (a) to (d): (a) at least two different organic diisocyanate compounds and / or polyisocyanate compounds; (b) polyol compounds; (c) an acidic group-containing compound containing at least two compounds, which are a compound containing a carboxyl group as an acid group (a carboxyl group-containing compound) and a compound containing a sulfo group as an acid group (a sulfo group-containing compound); and (d) a chain extender selected from the group consisting of polyamine compounds, diamine compounds, polyol compounds, and alkanolamine compounds, the chain extender having a molecular weight of 400 or less; An aqueous polyurethane resin composition comprising a polyurethane resin obtained from An aqueous polyurethane resin composition having a viscosity of 500 Pa·s or more and 50,000 Pa·s or less when the polyurethane resin is contained in an amount of 65% by weight.

[0008] [2] The aqueous polyurethane resin composition according to [1], wherein the acidic group-containing compound of component (c) is a compound having two or more hydroxy groups or amino groups.

[0009] [3] The aqueous polyurethane resin composition according to [1] or [2], which contains at least two different organic diisocyanate compounds as the component (a).

[0010] [4] The aqueous polyurethane resin composition according to any one of [1] to [3], wherein the organic diisocyanate compound contains at least one kind of alicyclic diisocyanate compound.

[0011] [5] The aqueous polyurethane resin composition according to any one of [1] to [4], wherein at least one of the organic diisocyanate compounds is an alicyclic diisocyanate compound selected from 4,4'-diisocyanatodicyclohexylmethane and isophorone diisocyanate, and the alicyclic diisocyanate compound is contained in an amount of 80 mol % or less relative to 100 mol % of the organic diisocyanate compound of component (a).

[0012] [6] The aqueous polyurethane resin composition according to any one of [1] to [5], wherein the polyol compound of the component (b) contains a polyether polyol.

[0013] [7] The aqueous polyurethane resin composition according to any one of [1] to [6], wherein the component (b) is polytetramethylene glycol polyol.

[0014] [8] The aqueous polyurethane resin composition according to any one of [1] to [7], wherein the component (b) has an average molecular weight of more than 400 g / mol and not more than 6000 g / mol.

[0015] [9] The aqueous polyurethane resin composition according to any one of [1] to [8], wherein the proportion of the component (b) contained in the polyurethane resin is 60% by weight or more.

[0016]

[10] The aqueous polyurethane resin composition according to any one of [1] to [9], wherein the component (c) is present in the polyurethane resin in an amount such that the total weight of the carboxyl group-containing compound and the sulfo group-containing compound is 0.2 to 10% by weight, preferably 0.5 to 5% by weight.

[0017]

[11] The aqueous polyurethane resin composition according to any one of [1] to

[10] , wherein the ratio of the acid value of the carboxylic acid group to the total acid value in component (c) is 0.20 to 0.95, more preferably 0.50 to 0.90, and even more preferably 0.70 to 0.85.

[0018]

[12] The aqueous polyurethane resin composition according to any one of [1] to

[11] , wherein the acid value of the carboxylic acid group in the polyurethane resin is preferably in the range of 4.5 to 30 mgKOH / g, more preferably in the range of 5 to 25 mgKOH / g, and even more preferably in the range of 6 to 22 mgKOH / g.

[0019]

[13] The aqueous polyurethane resin composition according to any one of [1] to

[12] , wherein the polyurethane resin is contained in an amount of 20 to 65% by weight.

[0020]

[14] A paint composition, a coating composition, an ink composition, or an adhesive composition, which contains the aqueous polyurethane resin composition according to any one of [1] to

[13] . [Effects of the Invention]

[0021] According to the aqueous polyurethane resin composition of the present invention, it is possible to provide an aqueous polyurethane resin composition that is excellent in finished appearance, and further, it is possible to provide an aqueous polyurethane resin composition that is excellent in impact resistance, such as chipping resistance, and adhesion. DETAILED DESCRIPTION OF THE INVENTION

[0022] The present invention provides an aqueous polyurethane resin composition comprising: (a) at least two different organic diisocyanate compounds and / or polyisocyanate compounds; (b) a polyol compound; (c) an acidic group-containing compound including at least two compounds, the compounds being a compound containing a carboxyl group as an acid group (a carboxyl group-containing compound) and a compound containing a sulfo group as an acid group (a sulfo group-containing compound); and (d) a chain extender selected from the group consisting of polyamine compounds, diamine compounds, polyol compounds, and alkanolamine compounds, the chain extender having a molecular weight of 400 or less; wherein the aqueous polyurethane resin composition has a viscosity of 500 Pa·s or more and 50,000 Pa·s or less when the polyurethane resin is contained in an amount of 65% by weight.

[0023] [Component (a): Organic diisocyanate compound and polyisocyanate compound] In the present invention, component (a) is at least two different organic diisocyanate compounds and / or polyisocyanate compounds.

[0024] The organic diisocyanate compound of component (a) is an organic compound having two free isocyanate groups per molecule, and an example thereof is diisocyanate Y(NCO)2 [Y is C 4-12 Divalent aliphatic hydrocarbon group (=aliphatic diisocyanate compound), C 6-15 Divalent alicyclic hydrocarbon group (=alicyclic diisocyanate compound), C 6-15 Divalent aromatic hydrocarbon group (= aromatic diisocyanate compound) or C 7-15It is a divalent aromatic aliphatic hydrocarbon group.] Examples of such organic diisocyanate compounds include tetramethylene diisocyanate, methyl pentamethylene diisocyanate, 1,5-pentamethylene diisocyanate, hexamethylene diisocyanate (=HDI), dodecamethylene diisocyanate, 1,2-bis(isocyanatomethyl)cyclohexane, 1,4-diisocyanatocyclohexane, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (=IPDI, isophorone diisocyanate), 4,4'-diisocyanatomethylcyclohexane, 1,4-diisocyanatomethylcyclohexane ...methylcyclohexane, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (=IPDI, isophorone diisocyanate), 4,4'-diisocyanatomethylcyclohexane, 1,4-diisocyanatomethylcyclohexane, 1,5-pentamethylene diisocyanate, hexamethylene diisocyanate (=HDI), dodecamethylene diisocyanate, 1,2-bis(isocyanatomethyl)cyclohexane Diisocyanatodicyclohexylmethane, 4,4'-diisocyanatodicyclohexylpropane-(2,2), 1,4-diisocyanatobenzene, 2,4-diisocyanatotoluene, 2,6-diisocyanatotoluene, 4,4'-diisocyanatodiphenylmethane, 2,2'-diisocyanatodiphenylmethane, 2,4'-diisocyanatodiphenylmethane, tetramethylxylylene diisocyanate, p-xylylene diisocyanate, p-isopropylidenediisocyanate, and 1,5-diisocyanatonaphthalene.

[0025] The organic polyisocyanate compound of component (a) is a polyisocyanate having three or more isocyanate groups per molecule. Examples of such organic polyisocyanate compounds include polyisocyanates produced by modifying aliphatic, alicyclic, araliphatic, and / or aromatic diisocyanates, consisting of at least two diisocyanates, and having a uretdione, isocyanurate, urethane, allophanate, biuret, carbodiimide, iminooxadiazinedione, and / or oxadiazinetrione structure. Examples of unmodified polyisocyanates having three or more isocyanate groups per molecule include 4-isocyanatomethyl-1,8-octane diisocyanate (nonane triisocyanate).

[0026] Component (a) preferably contains at least two organic diisocyanate compounds that are different from each other.

[0027] In order to provide a coating film with high fracture strength and enhanced durability, the organic diisocyanate compound of component (a) preferably contains at least one alicyclic diisocyanate compound.

[0028] To facilitate reaction control, component (a) preferably contains at least one alicyclic diisocyanate compound selected from 4,4'-diisocyanatodicyclohexylmethane and isophorone diisocyanate.

[0029] Component (a) contains an alicyclic diisocyanate compound in a proportion of preferably 80 mol % or less, more preferably 20 to 70 mol %, and even more preferably 40 to 60 mol %, relative to 100 mol % of the organic diisocyanate compound of component (a). If the proportion of the alicyclic diisocyanate compound in the organic diisocyanate compound is too high, impact resistance such as chipping resistance may decrease in some cases, so the amount of the alicyclic diisocyanate compound is preferably within the above-mentioned specific range.

[0030] Component (a) is preferably a combination of an aliphatic diisocyanate compound and an alicyclic diisocyanate compound selected from 4,4'-diisocyanatodicyclohexylmethane, isophorone diisocyanate, and mixtures thereof.

[0031] Component (a) is more preferably a combination of an alicyclic diisocyanate compound selected from 4,4'-diisocyanatodicyclohexylmethane or isophorone diisocyanate and hexamethylene diisocyanate (=HDI), which is an aliphatic diisocyanate compound.

[0032] The proportion of component (a) contained in the polyurethane resin is usually 5 to 30% by weight, preferably 10 to 25% by weight, and more preferably 13 to 20% by weight.

[0033] [Component (b): Polyol compound] The polyol compound of component (b) has a molecular weight greater than 400 and at least two isocyanate-reactive hydroxyl groups. Examples of polyol compounds include polyether polyols, polyester polyols, polycarbonate polyols, polyester polycarbonate polyols, polylactone polyols, polybutadiene polyols, and silicone polyols.

[0034] The preferred component (b) has preferably 2 to 4 hydroxyl groups, particularly preferably 2 to 3, and most preferably 2. Furthermore, the component (b) may be a mixture of various compounds of this type.

[0035] Examples of polyether polyols include cyclic ether polyadducts and polyhydric alcohol condensates. Examples of cyclic ethers include styrene oxide, ethylene oxide, propylene oxide, tetrahydrofuran, butylene oxide, and epichlorohydrin, which may be used alone or in combination. Examples of polyhydric alcohols include the aforementioned diols and high-functionality polyols, which may be used alone or in combination. For example, a polyadduct of tetrahydrofuran is known as polytetramethylene ether glycol (PTMG).

[0036] Polyester polyols can be produced by adjusting the production conditions of polyesters and are polyesters having hydroxyl groups at least at both ends of the main chain. Examples of polyester polyols include linear polyester diols and slightly branched polyester polyols. They can be produced by known methods using aliphatic, alicyclic, or aromatic dicarboxylic acids and diols, and optionally polycarboxylic acids and / or highly functional polyols.

[0037] The polylactone polyol is a homopolymer or copolymer of lactone, and is a polylactone produced so as to have hydroxyl groups at least at both ends of the main chain.

[0038] Polycarbonate polyol is a polycarbonate having hydroxyl groups at least at both ends of the main chain, which is produced by adjusting the production conditions of the polycarbonate.

[0039] Silicone polyols include silicone oils having siloxane bonds in the molecule and hydroxyl groups at the ends.

[0040] The polyol compound of component (B) preferably comprises a polyether polyol.

[0041] When component (b) contains a polyether polyol, the content of the polyether polyol in component (b) is preferably 50 to 100% by weight, more preferably 60 to 100% by weight, and even more preferably 75 to 100% by weight. A content of 50% or more improves strength. Furthermore, an optional component such as a polycarbonate polyol can be used in combination, and its content is 50% by weight or less, preferably 40% by weight or less, and even more preferably 25% or less.

[0042] The average molecular weight of the polyol compound of component (B), particularly the average molecular weight of polytetramethylene glycol polyol, is greater than 400 g / mol and not greater than 6,000 g / mol, preferably 800 to 5,000 g / mol, and more preferably 1,000 to 4,000 g / mol. When the average molecular weight is greater than 400 g / mol, sufficient adhesion of the coating film to the substrate can be obtained. When the average molecular weight is not greater than 6,000 g / mol, the dispersion stability of the aqueous polyurethane resin composition and / or the finished appearance of the coating film can be improved.

[0043] From the viewpoint of adhesion of the coating film, the proportion of component (b) contained in the polyurethane resin is preferably 60% by weight or more, more preferably 65 to 85% by weight, and even more preferably 70 to 85% by weight.

[0044] In this specification, the polyol compound of component (b) excludes the acidic group-containing diol compound of component (c).

[0045] [Component (c): acidic group-containing compound] The acidic group-containing compound of component (c) includes at least two types of compounds, namely, a compound containing a carboxyl group as an acid group (a carboxyl group-containing compound) and a compound containing a sulfo group as an acid group (a sulfo group-containing compound).

[0046] The acidic group-containing compound of component (c) is preferably a compound having at least two hydroxyl or amino groups.

[0047] Regarding component (c), the combination of a carboxyl group-containing compound and a sulfo group-containing compound enhances the emulsification / dispersibility of polyurethane resins in water, even with a low acid value. Furthermore, when this combination is mixed with other emulsion resins, pigments, additives, solvents, etc. and used as a coating material, the mixture has excellent storage stability and remains stable at low viscosity even with a high solids content.

[0048] Component (c) is present in the polyurethane resin in an amount such that the total weight of the carboxyl group-containing compound and sulfo group-containing compound is preferably 0.2 to 10 wt%, more preferably 0.5 to 5 wt%. When this amount is 0.2 wt% or more, sufficient water dispersibility is obtained. When this amount is 10 wt% or less, the strength and water resistance of the coating film are improved.

[0049] The ratio of the acid value of the carboxyl groups in component (c) to the total acid value is preferably 0.20 to 0.95, more preferably 0.50 to 0.90, and even more preferably 0.70 to 0.85. In this specification, the acid value refers to the calculated value (mgKOH / g) of potassium hydroxide required to neutralize the carboxyl groups or sulfo groups present in the polyurethane resin. Furthermore, the total acid value refers to the sum of the acid values ​​of the carboxyl groups and the sulfo groups.

[0050] Specific examples of the acidic group-containing compound of component (C) include N-(2-aminoethyl)-2-aminoethanesulfonic acid, N-(3-aminopropyl)-2-aminoethanesulfonic acid, N-(3-aminopropyl)-3-aminopropanesulfonic acid, N-(2-aminoethyl)-3-aminopropanesulfonic acid, 2,2-dimethylolpropionic acid, 2,2-dimethylolbutanoic acid, N,N-bishydroxyethylalanine, 3,4-dihydroxybutanesulfonic acid, 3,6-dihydroxy-2-toluenesulfonic acid, and the sodium, lithium, potassium, and tertiary amine salts of reaction products obtained by Michael addition of a diamine (e.g., 1,2-ethanediamine or isophoronediamine) with a two-fold molar amount of acrylic acid or maleic acid.

[0051] The acidic group-containing compound of component (c) is preferably an acidic group-containing diol compound, for example, an acidic group-containing diol compound having 4 to 12 carbon atoms, such as 2,2-dimethylolpropionic acid, 2,2-dimethylolbutanoic acid, N,N-bishydroxyethylglycine, N,N-bishydroxyethylalanine, 3,4-dihydroxybutanesulfonic acid, and 3,6-dihydroxy-2-toluenesulfonic acid.

[0052] The acidic group-containing compound of component (C) may be any compound that contains or can form an ionic group, such as dihydroxycarboxylic acids, diaminocarboxylic acids, dihydroxysulfonic acids, diaminosulfonic acids, and their salts. Examples include dimethylolpropionic acid, hydroxypivalic acid, 2-(2-aminoethylamino)ethanesulfonic acid, ethylenediaminepropyl or butylsulfonic acid, 1,2- or 1,3-propylenediamine-β-ethylsulfonic acid, lysine, 3,5-diaminobenzoic acid and its alkali and / or ammonium salts; an adduct of sodium hydrogen sulfate with butene-2-diol-1,4, polyethersulfone, a propoxylated adduct of 2-butenediol with NaHSO (German Patent Specification DE-A 2446440), and structural units that can be converted to cationic groups, such as N-methyldiethanolamine.

[0053] [Component (d): Polyamine compounds, diamine compounds, polyol compounds, and alkanolamine compounds as chain extenders] Component (d) is a polyamine compound, diamine compound, polyol compound and / or alkanolamine compound as a chain extender, and these compounds have a molecular weight of 400 or less.

[0054] The polyamine compound of component (d) is a polyamine having a total of three or more amino and / or imino groups in one molecule. Examples of the polyamine compound include triamine compounds such as diethylenetriamine, bis(2-aminopropyl)amine, and bis(3-aminopropyl)amine; tetraamine compounds such as triethylenetetramine, tripropylenetetramine, N-(benzyl)triethylenetetramine, N,N'''-(dibenzyl)triethylenetetramine, and N-(benzyl)-N'''-(2-ethylhexyl)triethylenetetramine; pentamine compounds such as tetraethylenepentamine and tetrapropylenepentamine; hexamine compounds such as pentaethylenehexamine and pentapropylenehexamine; and polyamine compounds such as polyethyleneimine and polypropyleneimine. From the viewpoint of reactivity with the polyurethane prepolymer, the polyamine is preferably a polyamine having two amino groups and one or more imino groups, such as diethylenetriamine, triethylenetetramine, bis(2-aminopropyl)amine, bis(3-aminopropyl)amine, tripropylenetetramine, tetraethylenepentamine, tetrapropylenepentamine, pentaethylenehexamine, or pentapropylenehexamine.

[0055] Examples of the diamine compound of component (d) include hydrazine, 1,2-ethanediamine, 1,4-tetramethylenediamine, 2-methyl-1,5-pentanediamine, 1,6-hexamethylenediamine, 1,4-hexamethylenediamine, 3-aminomethyl-3,5,5-trimethylcyclohexylamine, 1,3-bis(aminomethyl)cyclohexane, xylylenediamine, piperazine, 2,5-dimethylpiperazine, and the like.

[0056] The polyol compound of component (d) is a compound having two or more hydroxyl groups, examples of which include ethanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, 1,3-propanediol, 1,4-butanediol, 1,3-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, 2,2-dimethyl-1,3-propanediol, 1,4-dihydroxycyclohexane, 1,4-dimethylcyclohexane, and the like. Examples of cyclohexane include cyclohexane, 1,8-octanediol, 1,10-decanediol, 1,12-dodecanediol, neopentyl glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 1,4-dihydroxybenzene, 1,3-dihydroxybenzene, 1,2-dihydroxybenzene, 2,2-bis(4-hydroxyphenyl)-propane (bisphenol A), TCD-diol, trimethylolpropane, glycerol, pentaerythritol, and dipentaerythritol.

[0057] Examples of the alkanolamine compound of component (d) include ethanolamine, propanolamine, butylethanolamine, 1-amino-2-methyl-2-propanol, 2-amino-2-methylpropanol, diethanolamine, diisopropanolamine, dimethylamine, propylethanolamine, dipropanolamine, N-methylethanolamine, and N-ethylethanolamine.

[0058] The chain extender of component (d) may be used alone or in combination of two or more types.

[0059] The amount of the chain extender of component (d) is preferably equal to or less than the equivalent of the residual isocyanate groups that serve as chain extension initiation points in the polyurethane prepolymer, more preferably 0.7 to 0.99 equivalents of the residual isocyanate groups. When the amount of the chain extender of component (d) is equal to or less than the equivalent of the residual isocyanate groups, preferably 0.99 equivalents or less, a decrease in the molecular weight of the chain-extended polyurethane resin tends to be suppressed, and the strength of the coating film obtained by applying the resulting aqueous polyurethane resin dispersion tends to be improved.

[0060] In addition to the component (d), for example, an amino polyol compound, water, or the like may be further used as a chain extender.

[0061] The aqueous polyurethane resin composition may further contain, as optional components, a monoalcohol and a monoamine.

[0062] The amount of monoalcohol and monoamine added is preferably less than 5% by weight, more preferably less than 2% by weight, based on the solid content of the aqueous polyurethane resin.

[0063] [Method for producing aqueous polyurethane resin composition].

[0064] The method for producing the aqueous polyurethane resin composition is not particularly limited, but examples thereof include the following method.

[0065] The method for producing the aqueous polyurethane resin composition includes the steps of: (a) obtaining a polyurethane prepolymer by reacting at least two different organic diisocyanate compounds and / or polyisocyanate compounds, (b) a polyol compound, and (c) an acidic group-containing compound; neutralizing the acidic groups in the polyurethane prepolymer; dispersing the polyurethane prepolymer in an aqueous medium; and (d) reacting the polyurethane prepolymer with a chain extender selected from the group consisting of polyamine compounds, diamine compounds, polyol compounds, and alkanolamine compounds, and having a molecular weight of 400 or less, to obtain an aqueous polyurethane resin composition containing a polyurethane resin.

[0066] In the method for producing an aqueous polyurethane resin composition, the step of neutralizing the acidic groups and the step of dispersing the polyurethane prepolymer in an aqueous medium may be carried out separately or together. Furthermore, in the method for producing an aqueous polyurethane resin composition, the step of reacting the polyurethane prepolymer with a chain extender may be carried out after the step of dispersing the polyurethane prepolymer in an aqueous medium or may be carried out together with the step of dispersing the polyurethane prepolymer in an aqueous medium.

[0067] Each step in the method for producing the aqueous polyurethane resin composition may be carried out in an inert gas atmosphere or in the air.

[0068] The polyurethane resin composition of the present invention contains a polyurethane resin, and is preferably a dispersion dispersed in an aqueous medium. The polyurethane resin composition of the present invention contains at least water as the aqueous medium and an organic solvent as a co-solvent, such as a ketone solvent (e.g., acetone and methyl ethyl ketone), an ester solvent (e.g., ethyl acetate), an ether solvent (e.g., tetrahydrofuran), an amide solvent (e.g., N,N-dimethylformamide and N-methylpyrrolidone), an alcohol solvent (e.g., isopropyl alcohol), or an aromatic hydrocarbon solvent (e.g., toluene). The amount of the co-solvent contained in the polyurethane resin composition of the present invention is preferably 10% by weight or less. Furthermore, the proportion of water in the aqueous medium is preferably 40% by weight or more.

[0069] The solids concentration (content of components other than volatile components) of the aqueous dispersion of the aqueous polyurethane resin obtained by the present invention is preferably 20 to 65% by weight, more preferably 30 to 60% by weight, from the viewpoint of ease of handling of the aqueous dispersion. The solids concentration can be obtained as follows: About 1 g of the aqueous dispersion is thinly spread on a petri dish; the aqueous dispersion is precisely weighed; the dispersion is then heated at 130°C for 45 minutes using a circulating thermostatic dryer, and the weight after heating is precisely weighed; and the ratio (%) of the residual weight after heating to the weight before heating is calculated.

[0070] The aqueous polyurethane resin composition may optionally contain a neutralizing agent. The neutralizing agent neutralizes at least a portion of the acidic groups of the polyurethane prepolymer and can be used to disperse the polyurethane prepolymer in an aqueous medium. Examples of neutralizing agents include tertiary amine compounds such as trialkylamines (e.g., trimethylamine, triethylamine, tributylamine), N,N-dialkylalkanolamines (e.g., N,N-dimethylethanolamine, N,N-dimethylpropanolamine, N,N-dipropylethanolamine, 1-dimethylamino-2-methylpropanol), N-alkyl-N,N-dialkanolamines, and trialkanolamines (e.g., triethanolamine); inorganic alkali salts (e.g., potassium hydroxide, sodium hydroxide); and ammonia. These may be used alone or in combination of two or more.

[0071] From the viewpoint of workability, the neutralizing agent is preferably an organic amine, more preferably N,N-dimethylethanolamine. The amount of the neutralizing agent is, for example, 0.4 to 1.2 equivalents, preferably 0.6 to 1.0 equivalents per equivalent of the acidic groups in the aqueous polyurethane resin composition.

[0072] The aqueous polyurethane resin composition of the present invention has a viscosity of 500 Pa·s or more and 50,000 Pa·s or less when the polyurethane resin is contained in an amount of 65% by weight. When the polyurethane resin is contained in an amount of 80% by weight, the viscosity change rate is 350% or less, preferably 250% or less, and particularly preferably 150% or less. By having the above-specified viscosity, the aqueous polyurethane resin composition of the present invention provides paint compositions, coating compositions, ink compositions, and adhesive compositions with excellent finished appearance.

[0073] In this specification, the viscosity of an aqueous polyurethane resin composition having a high solids content is measured using a rheometer after adjusting the liquid temperature to 25° C. When the aqueous polyurethane resin composition contains less than 65% by weight of polyurethane resin, for example, the aqueous medium in the aqueous polyurethane resin composition can be evaporated using an evaporator or the like to adjust the polyurethane resin content, thereby making it possible to measure the viscosity when the polyurethane resin is contained in an amount of 65% by weight or more.

[0074] [Viscosity change rate] The "viscosity change rate" in the present invention refers to the change in viscosity when the solid content of the aqueous polyurethane resin composition is increased from 65% by weight to 80% by weight, and is calculated using the following method. Note that the viscosity at a high solid content is measured using a rheometer at 25°C.

[0075] (Viscosity change rate (%)) = {(Viscosity when the solid content is 80% by weight) - (Viscosity when the solid content is 65% by weight)} / (Viscosity when the solid content is 65% by weight) × 100 The average molecular weight of the polyurethane resin in the aqueous polyurethane resin composition of the present invention is not particularly limited and can be selected within a range that provides dispersibility and a good coating film as an aqueous coating material, and is preferably 5,000 to 500,000, more preferably 10,000 to 100,000. In this specification, the average molecular weight of the polyurethane resin is a weight average molecular weight measured by gel permeation chromatography, and polystyrene is used as a standard substance.

[0076] The acid value of the carboxyl group in the polyurethane resin in the aqueous polyurethane resin composition of the present invention is preferably in the range of 4.5 to 30 mgKOH / g, more preferably in the range of 5 to 25 mgKOH / g, and even more preferably in the range of 6 to 22 mgKOH / g. In this specification, the acid value of the resin means the number of milligrams of potassium hydroxide required to neutralize 1 g of the resin. The acid value is a value measured in accordance with the indicator titration method of JIS K 1557.

[0077] The hydroxyl value of the polyurethane resin in the aqueous polyurethane resin composition of the present invention is not particularly limited, but is usually in the range of 1 to 100 mgKOH / g. In this specification, the hydroxyl value of the resin means the number of milligrams (mg) of potassium hydroxide corresponding to the hydroxyl groups in 1 g of the resin. The hydroxyl value is a value measured in accordance with the indicator titration method of JIS K 1557, Method B.

[0078] The aqueous polyurethane resin composition of the present invention can be used alone or in combination with binders, auxiliaries, and additives known in the fields of coatings and adhesives (e.g., emulsifiers, light stabilizers such as UV absorbers and sterically hindered amines (HALS), antioxidants, fillers, anti-settling agents, antifoaming agents, and / or wetting agents, flow improvers, reactive diluents, plasticizers, neutralizers, catalysts, cosolvents, and / or thickeners, as well as additives such as pigments, colorants, or leveling agents). Tackifiers can also be added. The additives can be added to the product of the present invention immediately before processing. However, it is also possible to add at least a portion of the additives before or during the dispersion of the binder.

[0079] [Paint compositions containing aqueous polyurethane resin compositions, etc.] The present invention also relates to a paint composition, a coating composition, an ink composition and an adhesive composition containing the aqueous polyurethane resin composition.

[0080] In addition to the aqueous polyurethane resin composition, other resins may be added to the paint, coating, ink, and adhesive compositions of the present invention.

[0081] Examples of other resins include polyester resins, acrylic resins, polyether resins, polycarbonate resins, polyurethane resins, epoxy resins, alkyd resins, polyolefin resins, vinyl chloride resins, etc. These may be used alone or in combination of two or more.

[0082] From the viewpoint of dispersibility in water, the other resin preferably has one or more types of hydrophilic groups, such as a hydroxyl group, a carboxyl group, a sulfo group, and a polyethylene glycol group.

[0083] Polyester resins can usually be produced by esterification or transesterification between an acid component and an alcohol component. The acid component can be any compound commonly used as an acid component in producing polyester resins. For example, aliphatic polybasic acids, alicyclic polybasic acids, aromatic polybasic acids, etc. can be used as the acid component.

[0084] The acrylic resin is preferably, for example, a hydroxyl group-containing acrylic resin, which can be produced by a known method such as solution polymerization in an organic solvent or emulsion polymerization in water, in which a hydroxyl group-containing polymerizable unsaturated monomer is copolymerized with another polymerizable unsaturated monomer that is copolymerizable with the hydroxyl group-containing polymerizable unsaturated monomer.

[0085] The hydroxyl group-containing polymerizable unsaturated monomer is a compound having one or more hydroxyl groups and one or more polymerizable unsaturated bonds in one molecule. Examples include monoesterification products of (meth)acrylic acid and dihydric alcohols having 2 to 8 carbon atoms, such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate; ε-caprolactone-modified products of these monoesterification products; N-hydroxymethyl (meth)acrylamide; allyl alcohol; and (meth)acrylates having polyoxyethylene chains with hydroxyl groups at the molecular terminals.

[0086] The hydroxyl group-containing acrylic resin preferably has an anionic functional group. The hydroxyl group-containing acrylic resin having an anionic functional group can be produced, for example, by using a polymerizable unsaturated monomer having an anionic functional group such as a carboxylic acid group, a sulfonic acid group, or a phosphoric acid group as one type of polymerizable unsaturated monomer.

[0087] Examples of polyether resins include polymers or copolymers having an ether bond, such as polyoxyethylene-based polyethers, polyoxypropylene-based polyethers, polyoxybutylene-based polyethers, and polyethers derived from aromatic polyhydroxy compounds including bisphenol A and bisphenol F.

[0088] Examples of polycarbonate resins include polymers made from bisphenol A, 3-methyl-1,5-pentanediol, and 1,6-hexanediol.

[0089] Examples of epoxy resins include resins obtained by reacting bisphenol compounds with epichlorohydrin. Examples of bisphenols include bisphenol A and bisphenol F.

[0090] Examples of alkyd resins include alkyd resins obtained by further reacting polybasic acids such as phthalic acid, terephthalic acid or succinic acid and polyhydric alcohols with modifiers such as fats and oils / fatty and oily acids (soybean oil, linseed oil, palm oil, stearic acid, etc.) or natural resins (rosin, amber, etc.).

[0091] Examples of polyolefin resins include those obtained by polymerizing or copolymerizing an olefin monomer with another monomer according to a suitable conventional polymerization method, and then dispersing the resulting polyolefin resin in water using an emulsifier, or by emulsion polymerizing an olefin monomer with another monomer. Furthermore, in some cases, so-called chlorinated polyolefin-modified resins obtained by chlorinating a polyolefin resin may also be used.

[0092] Examples of olefinic monomers include α-olefins such as ethylene, propylene, 1-butene, 3-methyl-1-butene, 4-methyl-1-pentene, 3-methyl-1-pentene, 1-heptene, 1-hexene, 1-decene, and 1-dodecene; and conjugated and non-conjugated dienes such as butadiene, ethylidene norbornene, dicyclopentadiene, 1,5-hexadiene, and styrenes. These monomers may be used alone or in combination of two or more.

[0093] Examples of other monomers copolymerizable with the olefinic monomer include vinyl acetate, vinyl alcohol, maleic acid, citraconic acid, itaconic acid, maleic anhydride, citraconic anhydride, itaconic anhydride, etc. These monomers may be used alone or in combination of two or more.

[0094] The paint composition, coating composition, ink composition, and adhesive composition of the present invention can further contain a curing agent. By containing a curing agent, the durability of the coating film, multi-layer coating film, coating film, or printed matter obtained by using the coating composition, ink composition, or adhesive composition can be improved.

[0095] For example, polyisocyanate, blocked polyisocyanate, melamine resin, carbodiimide, oxazoline, aziridine, hydrazine, etc. These curing agents may be used alone or in combination of two or more.

[0096] The polyisocyanate is not particularly limited as long as it has two or more isocyanate groups in the molecule, and examples thereof include the same compounds as those exemplified as the polyisocyanate compound (a).

[0097] The blocked polyisocyanate is not particularly limited as long as the blocked polyisocyanate has two or more blocked isocyanate groups in the molecule, and examples thereof include those obtained by blocking the polyisocyanate compound (a) or a compound obtained by imparting hydrophilicity to the polyisocyanate compound (a) with a known blocking agent [phenols, secondary or tertiary alcohols, oximes, aliphatic or aromatic secondary amines, phthalimide, lactams, active methylene compounds (dialkyl malonate, etc.), pyrazole compounds (pyrazole, 3,5-dimethylpyrazole, etc.), acidic sodium sulfite, etc.].

[0098] The melamine resin is not particularly limited, and any commonly used curing agent can be used. For example, the melamine resin is preferably an alkyl-etherified melamine resin obtained by alkyl-etherification, more preferably a melamine resin substituted with a methoxy group and / or a butoxy group. Such melamine resins include those having a single methoxy group, such as Cymel 325, Cymel 327, Cymel 370, and Mycoat 723; Cymel 202, Cymel 204, Cymel 211, Cymel 232, Cymel 235, Cymel 236, Cymel 238, Cymel 251, Cymel 254, Cymel 266, Cymel 267, and Cymel 285 (all of which are trademarks manufactured by Nippon Cytec Industries, Ltd.). and those having only a butoxy group, such as My coat 506 (trade name, manufactured by Mitsui-Cytec Ltd.), U-VAN20N60, and U-VAN20SE (all of which are trade names, manufactured by Mitsui Chemical, Inc.). These may be used alone or in combination of two or more. Of these, Cymel 211, Cymel 251, Cymel 285, Cymel 325, Cymel 327, and My coat 723 are more preferred.

[0099] The carbodiimide is not particularly limited as long as it is a compound having two or more carbodiimide groups in the molecule. For example, aliphatic polycarbodiimides [such as poly(hexamethylenecarbodiimide)], alicyclic polycarbodiimides [such as poly(4,4'-dicyclohexylmethanecarbodiimide)], and aromatic polycarbodiimides [such as poly(p-phenylenecarbodiimide), poly(4,4'-diphenylmethanecarbodiimide), and poly(diisopropylphenylcarbodiimide)] obtained by polymerizing an aromatic polyisocyanate having 8 to 26 carbon atoms, an aliphatic polyisocyanate having 4 to 22 carbon atoms, an alicyclic polyisocyanate having 8 to 18 carbon atoms, or an aromatic aliphatic polyisocyanate having 10 to 18 carbon atoms can be used. Examples of commercially available products include "Carbodilite V-01," "Carbodilite V-02," "Carbodilite V-03," "Carbodilite V-04," "Carbodilite V-05," "Carbodilite V-07," "Carbodilite V-09," "Carbodilite E-02," "Carbodilite E-03A," and "Carbodilite E-04," all manufactured by Nisshinbo Chemical Inc.

[0100] The oxazoline is not particularly limited as long as it is a compound having two or more oxazoline groups (oxazoline skeletons) in the molecule. Examples include compounds having two or more oxazoline groups, such as 2,2'-isopropylidenebis(4-phenyl-2-oxazoline); (co)polymers of polymerizable oxazoline compounds, such as 2-isopropenyl-2-oxazoline, 2-vinyl-2-oxazoline, and 2-vinyl-4-methyl-2-oxazoline; and copolymers of polymerizable oxazoline compounds and copolymerizable monomers that do not react with oxazoline groups [(meth)acrylic acid esters, such as methyl (meth)acrylate, ethyl (meth)acrylate, hydroxyethyl (meth)acrylate, polyethylene glycol (meth)acrylate, (meth)acrylamidovinyl acetate, styrene, and sodium α-methylstyrene styrenesulfonate]. Examples of commercially available products include "Epocros K-2010E," "Epocros K-2020E," and "Epocros WS-500" manufactured by Nippon Shokubai Co., Ltd.

[0101] The aziridine is not particularly limited as long as it is a compound having two or more aziridinyl groups in the molecule, and examples thereof include tetramethylolmethane tris(β-aziridinylpropionate) and trimethylolpropane tris(β-aziridinylpropionate).

[0102] Examples of hydrazines include hydrazine and compounds having two or more hydrazine groups (hydrazine skeletons) in the molecule [for example, dicarboxylic acid dihydrazides having 2 to 10 carbon atoms (oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide, adipic acid dihydrazide, sebacic acid dihydrazide, maleic acid dihydrazide, fumaric acid dihydrazide, itaconic acid dihydrazide, etc.)], and alkylene dihydrazines having 2 to 10 carbon atoms (ethylene dihydrazine, 1,3-propylene dihydrazine, 1,4-butylene dihydrazine, 1,6-hexylene dihydrazine, etc.)].

[0103] Color pigments, extender pigments and luster pigments can be added to the paint, coating and ink compositions of the present invention.

[0104] Examples of color pigments include titanium oxide, zinc oxide, carbon black, molybdenum red, Prussian blue, cobalt blue, azo pigments, phthalocyanine pigments, quinacridone pigments, isoindoline pigments, selenium pigments, and perylene pigments. Titanium oxide and / or carbon black are preferably used as the color pigment. These may be used alone or in combination of two or more.

[0105] Examples of extender pigments include clay, kaolin, barium sulfate, barium carbonate, calcium carbonate, talc, silica, and alumina white. Barium sulfate and / or talc are preferably used as extender pigments, and barium sulfate is more preferably used. These can be used alone or in combination of two or more.

[0106] For example, aluminum, copper, zinc, brass, nickel, aluminum oxide, mica, aluminum oxide coated with titanium oxide or iron oxide, or mica coated with titanium oxide or iron oxide can be used as the luster pigment.

[0107] The paint composition, coating composition, ink composition, and adhesive composition of the present invention may contain, depending on their function or application, conventional additives such as thickeners, curing catalysts, ultraviolet absorbers, light stabilizers, antifoaming agents, plasticizers, surface conditioners, and anti-settling agents. These may be used alone or in combination of two or more, or commercially available products may be used as they are.

[0108] The method for producing the paint composition, coating composition, ink composition, or adhesive composition of the present invention is not particularly limited, and any known production method can be used. The paint composition, coating composition, ink composition, or adhesive composition of the present invention can be suitably produced by mixing the aqueous polyurethane resin composition with the various resins and additives described above, adding an aqueous medium, and adjusting the viscosity depending on the application method.

[0109] Suitable materials to which the paint composition, coating composition, ink composition, and adhesive composition of the present invention can be applied include metal materials commonly used for automobile bodies and parts, road materials, residential building materials, etc. (e.g., electrodeposition-coated steel sheets, phosphate steel sheets, zinc-plated steel sheets, cold-rolled steel sheets, aluminum sheets, stainless steel sheets, zinc phosphate-treated steel sheets, iron phosphate-treated steel sheets, etc.); and plastic materials such as polyurethane, polycarbonate, polybutylene terephthalate, polyamide, polyphenylene oxide, acrylonitrile / butadiene / styrene copolymer (i.e., ABS resin), polypropylene, and unsaturated polyester (commonly abbreviated as SMC). However, the present invention is not limited to these.

[0110] The material can be used as is, or can be subjected to a surface treatment such as degreasing or a primer coating and / or an intermediate coating. These treatments can be performed alone or in combination of two or more.

[0111] In order to repair a multilayer coating film previously applied to the above-mentioned material using the paint composition, coating composition, ink composition or adhesive composition of the present invention, it is preferable to first subject the coating film portion requiring repair to solvent cleaning or sanding treatment, and then paint.

[0112] The paint composition, coating composition, ink composition, and adhesive composition of the present invention can be adjusted before use to have a specific viscosity suitable for conventional coating methods such as air spray, airless spray, or electrostatic coating, or required to obtain a desired film thickness. For example, to coat plastic materials, the aqueous paint composition is preferably adjusted before use by adding deionized water and, if necessary, additives such as thickeners and defoamers, so that it has a solids content of about 10 to 40% by weight and a viscosity of about 800 to 5,000 cps / 6 rpm (measured with a Brookfield viscometer).

[0113] The above-mentioned suitable materials can be coated with a monocoat of the paint composition, coating composition, ink composition, or adhesive composition of the present invention. An undercoat can be applied to the coating material coated with the paint composition, coating composition, ink composition, or adhesive composition of the present invention using the so-called wet-on-wet method or the wet-on-wet method after preheating. On the other hand, after applying the coating material of the paint composition, coating composition, ink composition, or adhesive composition of the present invention to the electrodeposited film, a topcoat can be applied using the wet-on-wet method or the wet-on-wet method after preheating. Preheating is performed at 40 to 80°C for 5 to 60 minutes, for example, at 80°C for 5 minutes, and can be performed by hot air heating, infrared irradiation, or the like.

[0114] The dry film thickness of the paint composition, coating composition, ink composition or adhesive composition used for coating varies depending on the coating method or needs, but can usually be about 10 to 50 μm.

[0115] The applied paint composition, coating composition, ink composition, or adhesive composition is then dried completely or incompletely by setting at room temperature, air drying, or forced drying using hot air or an infrared heater, or optionally baked at a temperature of 120°C or less to completely or incompletely cure the composition, thereby obtaining an aqueous coating film. In particular, to form an aqueous coating film on a plastic material according to the present invention, it is preferable to obtain the aqueous coating film by coating, followed by air drying or hot air drying at 40 to 120°C to dry the film to a water content of about 25% by weight or less. Alternatively, to repair a multi-layer coating film, it is preferable to obtain the aqueous film by coating, followed by drying with air or hot air up to 80°C.

[0116] The aqueous polyurethane resin composition of the present invention has good fluidity even when the composition has a high solids content, so that coating materials using the composition have a good finished appearance. Furthermore, the coating film using the composition has good adhesion to substrates, particularly to electrodeposition coating films, and imparts excellent impact resistance to both single-coat (mono-coat) and multi-layer coating systems. The aqueous polyurethane resin composition of the present invention is suitable as a raw material for aqueous coating materials for coating electrodeposition films.

[0117] Example The present invention will now be described in more detail with reference to the following specific examples.

[0118] PolyTHF2000 is a polytetramethylene ether glycol (OH number: 56 mg KOH / g; number average molecular weight: 2000 g / mol) available from BASF AG.

[0119] PolyTHF1000 is a polytetramethylene ether glycol (OH number: 112 mg KOH / g; number average molecular weight: 1000 g / mol) available from BASF AG.

[0120] Desmophen 3600Z is a polypropylene oxide polyether polyol (OH number: 56 mg KOH / g; number average molecular weight: 2000 g / mol) available from Sumika Covestro Urethane Co., Ltd.

[0121] PolyTHF650 is a polytetramethylene ether glycol (OH number: 173 mg KOH / g; number average molecular weight 650 g / mol) available from BASF AG.

[0122] Desmophen C2202 is a polycarbonate polyol (OH number: 56 mg KOH / g; number average molecular weight: 2000 g / mol) available from Sumika Covestro Urethane Co., Ltd.

[0123] Desmophen 2028I is a polyester polyol available from Sumika Covestro Urethane Co., Ltd. (OH number: 56 mg KOH / g; number average molecular weight: 2000 g / mol).

[0124] IPDI is isophorone diisocyanate (Desmodur I) available from Sumika Covestro Urethane Co., Ltd.

[0125] HDI is hexamethylene diisocyanate (Desmodur H) available from Sumika Covestro Urethane Co., Ltd.

[0126] W is 4,4'-diisocyanatodicyclohexylmethane (Desmodur W) available from Sumika Covestro Urethane Co., Ltd.

[0127] AAS is sodium 2-[(2-aminoethyl)amino]ethanesulfonate available from FUJIFILM Wako Pure Chemical Corporation (product number: W01COBQV-7243).

[0128] DMPA is dimethylolpropionic acid (Bis-MPA) available from Tokyo Chemical Industry Co., Ltd.

[0129] AAP is sodium 3-[(2-aminoethyl)amino]propionate (product number: W01COBQV-3340) available from FUJIFILM Wako Pure Chemical Corporation.

[0130] EDA is ethylenediamine (E0077) available from Tokyo Chemical Industry Co., Ltd.

[0131] TMP is trimethylolpropane (T0480) available from Tokyo Chemical Industry Co., Ltd.

[0132] DEOA is diethanolamine (S0376) available from Tokyo Chemical Industry Co., Ltd.

[0133] DMEA is N,N-dimethylethanolamine (D0649) available from Tokyo Chemical Industry Co., Ltd.

[0134] [General method for measuring viscosity of aqueous polyurethane resin composition] Measurements were carried out at 25°C using a B-type rotational viscometer in accordance with JIS Z8803.

[0135] [Method for measuring viscosity of aqueous polyurethane resin compositions with high solids content, particularly when the polyurethane resin is contained in an amount of 65% by weight, and the aqueous polyurethane resin composition has a viscosity of 500 Pa·s or more and 50,000 Pa·s or less] The viscosity at high solids content can be measured when the polyurethane resin content is 65% by weight or more by, for example, evaporating the aqueous medium in the aqueous polyurethane resin composition using an evaporator or the like to adjust the polyurethane resin content. The viscosity was measured at 25°C using a rheometer (e.g., AR-G2, manufactured by TA Instruments). The measurement conditions used were gap: 0.25 mm; geometry: cone-plate; diameter: 20 mm; cone angle: 0.042 radians; and rotation speed: 0.1 s.

[0136] [Method for measuring the average molecular weight of the polyol compound of component (b)] To measure the average molecular weight of the polyol compound of component (b), a converted value obtained from a standard polystyrene calibration curve prepared in advance using gel permeation chromatography (GPC) was recorded.

[0137] [Method for measuring the average molecular weight of polyurethane resin] To measure the average molecular weight of the polyurethane resin, a converted value obtained from a standard polystyrene calibration curve prepared in advance using gel permeation chromatography (GPC) was recorded.

[0138] [Calculation method for acid value of polyurethane resin] The calculated value (mgKOH / g) is expressed as the number of mg of potassium hydroxide required to neutralize the carboxyl or sulfo groups present in the polyurethane resin. The ratio of the acid value of the carboxyl groups to the total acid value is calculated using the following formula. The total acid value refers to the sum of the acid value of the carboxyl groups and the acid value of the sulfo groups.

[0139] Ratio of the acid value of carboxyl groups to the total acid value = AV [COOH] / (AV [COOH] +AV [SO3H] ).

[0140] AV (total): The total acid value in the polyurethane resin (AV [COOH] +AV [SO3H] ) AV [COOH] : Acid value derived from the carboxyl group in the polyurethane resin AV [SO3H] : Acid value derived from sulfo groups in polyurethane resin [Method for measuring the hydroxyl value of polyurethane resin] The hydroxyl value of the polyurethane resin was measured in accordance with JIS K 1557, Method B.

[0141] [Production Example 1: Aqueous Polyurethane Resin Composition Example 1 (PUD No. 1)] A reaction vessel equipped with a stirrer and heater was charged with 4.19 parts by weight of PolyTHF1000 (component b1), 19.59 parts by weight of PolyTHF2000 (component b2), and 0.69 parts by weight of DMPA (component c) and heated to 70°C. Next, a mixture of 2.28 parts by weight of hexamethylene diisocyanate (component a1) and 3.02 parts by weight of isophorone diisocyanate (component a2) was added, and the mixture was stirred at 100-115°C until the NCO value was slightly lower than the theoretical value. The completed prepolymer was dissolved in acetone at 50°C to obtain a solution with a concentration of approximately 40%. Next, 0.46 parts by weight of DMEA was added for neutralization, and then a solution of 0.28 parts by weight of ethylenediamine (component d1), 0.31 parts by weight of AAS (component c), and 5.0 parts by weight of deionized water was metered in. The second stirring period was 15 minutes. After that, 64.18 parts by weight of deionized water was added to disperse the mixture, and the solvent was then removed by distillation under reduced pressure to obtain a dispersion with a solid content of 30.82% by weight and a viscosity of 2194 mPa·s (25°C, Brookfield viscometer, JIS Z8803).

[0142] [Production Examples 2 to 10 (Aqueous Polyurethane Resin Composition Examples 2 to 10 (PUD Nos. 2 to 10)) and Aqueous Polyurethane Resin Composition Comparative Examples 1 to 6 (PUD Nos. 11 to 16)] Aqueous polyurethane resin compositions Nos. 2 to 16 were obtained using the formulations shown in Table 1 below by the same procedure as in the aqueous polyurethane resin composition production example (PUD No. 1).

[0143] Table 1 shows the compositions of the aqueous urethane resin compositions and the viscosity values ​​at each concentration (unless otherwise specified, the values ​​in the table represent parts by weight). [Table 1] TIFF0007792337000002.tif207133TIFF0007792337000003.tif208143

[0144] Setaqua B E270 is a polyester dispersion available from Nuplex Industries Ltd. (OH number: 96 mg KOH / g; number average molecular weight: 1000 g / mol).

[0145] Envirogem AD-01 is a surface conditioner available from Air Products Japan KK.

[0146] TEGO WET 775W is a pigment dispersant available from Evonik Japan Co., Ltd.

[0147] JR-806 is a titanium white available from Teyka Corporation.

[0148] [Pigment dispersion paste] A stainless steel cylindrical stirring tank equipped with a stirrer was charged with 11.30 parts by weight of polyester dispersion Setaqua B E270, followed by 25.30 parts by weight of ion-exchanged water while stirring. Next, 1.60 parts by weight of a 10% aqueous solution of DMEA was added, followed by 1.60 parts by weight of pigment dispersant TEGO WET 775W while stirring. With thorough stirring, 1.30 parts by weight of surface conditioner Envirogem AD-01 was added. While continuing to stir, 58.90 parts by weight of titanium dioxide JR-806 was then added, and the mixture was stirred thoroughly for 15 minutes until the mixture was uniform, producing a pigment millbase. This millbase was then dispersed using a paint shaker to produce a pigment dispersion paste for aqueous primers. This had a nonvolatile content of 68.8% and a pigment concentration (PWC) of 85.0%.

[0149] The compounding ratio of the pigment dispersion paste is as shown in Table 2 below. [Table 2]

[0150] Cymel 327 is a melamine resin available from Mitsui-Cytec Ltd.

[0151] Bayhydrol A2770 is an acrylic dispersion available from Sumika Covestro Urethane Co., Ltd.

[0152] Byhidule BL2781 is a blocked isocyanate available from Sumika Covestro Urethane Co., Ltd.

[0153] [Production of Water-Based Paint Composition No. 1] 31.1 parts by weight of the pigment dispersion paste prepared according to Table 2, 21.8 parts by weight of the aqueous polyurethane resin composition No. 1 prepared in Preparation Example 1, 1.6 parts by weight of melamine resin Cymel 327, 19.4 parts by weight of acrylic dispersion Bayhydrol A 2770, 21.8 parts by weight of blocked isocyanate Byhidule BL 2781, and 4.3 parts by weight of deionized water were mixed and thoroughly stirred to obtain aqueous coating composition No. 1 with a solids content of 47% by weight. To achieve a viscosity suitable for spray coating, deionized water was added to obtain a viscosity of approximately 40 seconds at 20°C using a No. 4 Ford cup.

[0154] [Preparation of coated panels for evaluation] Aqueous coating composition No. 1 was air-sprayed onto an electrodeposited steel plate to coat it to a dry film thickness of 35 to 40 μm, and the plate was baked at 140° C. for 30 minutes to obtain a coated plate for evaluation.

[0155] Preparation of Water-Based Coating Compositions Nos. 2 to 10 (Examples 2 to 10) Aqueous coating compositions Nos. 2 to 10 were prepared by carrying out the same operations as in the production example for aqueous coating composition No. 1 having the formulation shown in Table 3 below, and coated panels for evaluation were produced using the same procedures.

[0156] Water-based paint composition No.11~No.16 (Comparative Examples 1~6) Aqueous coating compositions Nos. 11 to 16 were prepared in the same manner as in the production example for aqueous coating composition No. 1, which has the formulation shown in Table 3 below, and coated panels for evaluation were prepared using the same procedure.

[0157] [Test method] [Method for measuring the finished appearance] Multilayer coatings were prepared by vertical coating, and the gloss of the coatings was measured according to JIS K-5400 7.6 (1990) 60° specular gloss. A gloss value of 90 or more indicates an excellent finished appearance and is indicated by a double circle. Gloss values ​​of 80 or more and less than 90 are indicated by a circle, those of 70 or more and less than 80 by a triangle, and those less than 70 by an x.

[0158] [Method of measuring impact resistance] Chipping resistance: A test plate was attached to the test piece holder of a stone chipping tester JA-400 (manufactured by Suga Test Instruments Co., Ltd., trade name: chipping tester), and 50 g of crushed granite stone with a grain size of No. 7 was subjected to a pressure of 0.441 MPa (4.5 kgf / cm) at -20°C. 2 ) compressed air was sprayed onto the coated surface, and the degree of damage to the coating film caused by the stones was visually observed and evaluated.

[0159] Evaluation: Condition of the coating ◯: The electrodeposition film was exposed and the damage was small.

[0160] △: The damage is small, but the base steel plate is exposed.

[0161] ×: The damage is very severe and the base steel plate is largely exposed.

[0162] [Method for measuring adhesion] A cross-cut adhesion test (100 squares of 1 x 1 mm size, tape peeling) was carried out.

[0163] ○: Remaining squares 100 / 100 △: Remaining squares 95~99 / 100 ×: Less than 95 / 100 remaining squares The results of the evaluation tests are summarized in Table 3 (unless otherwise specified, the values ​​in the table represent parts by weight).

[0164] [Table 3] TIFF0007792337000006.tif245154TIFF0007792337000007.tif243155TIFF0007792337000008.tif244151

[0165] The results in Table 3 show that the aqueous coating composition of the present invention has a good finished appearance, good adhesion to the electrodeposition coating film, and excellent impact resistance. [Industrial Applicability]

[0166] The aqueous polyurethane resin composition of the present invention has good fluidity even when the solids concentration of the composition is high, so that coating materials using the composition have a good finished appearance. Furthermore, the coating film using the composition has good adhesion to substrates, particularly to electrodeposited coating films, and can impart excellent impact resistance to both single-coat (mono-coat) and multi-layer coating systems. Therefore, the aqueous polyurethane resin composition of the present invention is suitable as a raw material for aqueous coating materials for covering electrodeposited films.

[0167] According to the present invention, it is possible to obtain an aqueous polyurethane resin composition that has the contradictory required properties of excellent finished appearance, excellent adhesion to electrodeposited films, and impact resistance. The aqueous polyurethane resin composition of the present invention can be widely used as a raw material for paint compositions, coating compositions, ink compositions, adhesive compositions, etc.

Claims

1. At least the following components (a) to (d): (a) at least two different organic diisocyanate compounds; (b) a polyol compound; (c) an acidic group-containing compound containing at least two compounds, namely, a compound containing a carboxyl group as an acid group (a carboxyl group-containing compound) and a compound containing a sulfo group as an acid group (a sulfo group-containing compound); and (d) a chain extender selected from the group consisting of polyamine compounds, diamine compounds, polyol compounds, and alkanolamine compounds, the chain extender having a molecular weight of 400 or less An aqueous polyurethane resin composition comprising a polyurethane resin obtained from the aqueous polyurethane resin composition has a viscosity of 500 Pa·s or more and 50,000 Pa·s or less when the polyurethane resin is contained in an amount of 65% by weight, The aqueous polyurethane resin composition has a viscosity change rate of 350% or less, and the viscosity change rate is calculated as follows: (Viscosity change rate (%)) = {(Viscosity when the solid content is 80% by weight) - (Viscosity when the solid content is 65% by weight)} / (Viscosity when the solid content is 65% by weight) × 100 The viscosity is measured at 25°C, the component (a) is a combination of an aliphatic diisocyanate compound and an alicyclic diisocyanate compound selected from 4,4'-diisocyanatodicyclohexylmethane, isophorone diisocyanate, and a mixture thereof, and the alicyclic diisocyanate compound is contained in an amount of 80 mol % or less relative to 100 mol % of the organic diisocyanate compound of the component (a); the component (b) is a polytetramethylene glycol polyol, the component (b) has an average molecular weight higher than 400 g / mol and at least two isocyanate-reactive hydroxyl groups, and the proportion of the component (b) in the polyurethane resin is 60% by weight or more; The acidic group-containing diol compound of the component (c) is excluded from the component (b), The acidic group-containing compound of component (c) is a compound having at least two hydroxyl groups or amino groups, and an aqueous polyurethane resin composition, wherein the component (c) is present in the polyurethane resin in an amount such that the total weight of the carboxyl group-containing compound and the sulfo group-containing compound is 0.2 to 10% by weight.

2. The component (a) is a combination of an alicyclic diisocyanate compound selected from 4,4'-diisocyanatodicyclohexylmethane or isophorone diisocyanate and hexamethylene diisocyanate, which is an aliphatic diisocyanate compound. The aqueous polyurethane resin composition according to claim 1.

3. The aqueous polyurethane resin composition according to any one of claims 1 to 2, wherein the component (b) has an average molecular weight of 6000 g / mol or less.

4. 4. The aqueous polyurethane resin composition according to claim 1, wherein the ratio of the acid value of the carboxyl group to the total acid value in the component (c) is 0.20 to 0.

95.

5. 5. The aqueous polyurethane resin composition according to claim 1, wherein the acid value of the carboxyl group in the polyurethane resin is in the range of 4.5 to 30 mgKOH / g.

6. The aqueous polyurethane resin composition according to any one of claims 1 to 5, wherein the polyurethane resin is contained in an amount of 20 to 65% by weight.

7. A paint composition or coating composition comprising the aqueous polyurethane resin composition according to any one of claims 1 to 6.

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