Polyisocyanate composition, blocked polyisocyanate composition, coating composition, and coated substrate

Abstract

To provide a polyisocyanate composition and the like exhibiting superior dispersibility when combined with an aqueous main agent, and showing excellent gloss, water resistance, acid resistance, weather resistance, self-healing ability, and adhesion in the form of a coating film.SOLUTION: A polyisocyanate composition contains a polyisocyanate derived from an aliphatic chain diisocyanate, an anionic compound, and an alcohol, the anionic compound including an active hydrogen group, and the anionic compound having a mass fraction of 1.0 mass% to 8.0 mass% inclusive relative to the total mass of the polyisocyanate composition. The alcohol has an average hydroxyl number per molecule of 1.0 to 6.0 inclusive and a number average molecular weight of 100 to 7,000 inclusive. The polyisocyanate composition contains both an isocyanurate group and an allophanate group, with the molar fraction of the allophanate group relative to the total of the isocyanurate and allophanate groups being from 0.005 mol / mol to 0.850 mol / mol inclusive.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a polyisocyanate composition, a blocked polyisocyanate composition, a coating composition, and a coated substrate. [Background technology]

[0002] In recent years, water-based coating agents have been actively developed to reduce the amount of organic solvents used, from the viewpoints of protecting the global environment and improving occupational safety and hygiene. Two-component curable resin compositions consisting of a hydroxyl group-containing base agent (so-called polyol) and a polyisocyanate as a curing agent can be cured at room temperature and exhibit excellent mechanical properties, chemical resistance, durability, etc., and are therefore widely used in applications such as various paints and pressure-sensitive adhesives.

[0003] Regarding aqueous two-component curable resin compositions using such polyisocyanates as curing agents, many reports have been published so far, including polyalkylene oxide polyether alcohols and water-dispersible polyisocyanates that have been modified with anionic compounds to impart hydrophilicity.

[0004] For example, Patent Documents 1 and 2 disclose curing agents for aqueous two-component curable resins that are alicyclic polyisocyanates and contain ethylene oxide repeating units, thereby imparting compatibility with aqueous base resins. Patent Document 3 discloses a curing agent for an aqueous two-component curable resin that contains a specific anionic structure and a specific polyisocyanate, thereby imparting compatibility with an aqueous base resin and curing properties. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 8-085716 [Patent Document 2] Japanese Patent Application Publication No. 10-130353 [Patent Document 3] International Publication No. 2022 / 071361 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the polyisocyanate compositions having hydrophilic groups derived from polyalkylene oxide ether alcohols disclosed in Patent Documents 1 and 2 tend to have poor coating drying properties, and furthermore, the inclusion of an alicyclic diisocyanate poses the problem of insufficient coating film properties such as corrosion resistance.Furthermore, the curing agent for aqueous two-component curable resins disclosed in Patent Document 3 has an anionic structure that improves dispersibility, but the inclusion of bis(isocyanatomethyl)cyclohexane poses the problem of excessively high coating film hardness.

[0007] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a polyisocyanate composition that has good dispersibility when blended with an aqueous base agent and that, when formed into a coating film, has excellent gloss, water resistance, acid resistance, weather resistance, self-repairing property, and adhesion; a blocked polyisocyanate composition; a coating composition that uses the polyisocyanate composition or the blocked polyisocyanate composition; and a coating substrate. [Means for solving the problem]

[0008] That is, the present invention includes the following aspects. [1] A polyisocyanate composition comprising a polyisocyanate derived from an acyclic aliphatic diisocyanate (a), an anionic compound (b), and an alcohol (c), wherein the anionic compound (b) contains an active hydrogen group, and the mass fraction of the anionic compound (b) relative to the total mass of the polyisocyanate composition is 1.0 mass% or more and 8.0 mass% or less; the alcohol (c) has an average number of hydroxy groups per molecule of 1.0 to 6.0 and a number average molecular weight of 100 to 7,000; and the polyisocyanate composition contains isocyanurate groups and allophanate groups, and the molar fraction of the allophanate groups relative to the combined total of the isocyanurate groups and the allophanate groups is 0.005 mol / mol or more and 0.850 mol / mol or less. [2] The polyisocyanate composition according to [1], wherein the alcohol (c) has an average number of hydroxyl groups per molecule of 2.0 or more and 4.0 or less, and a number average molecular weight of 100 or more and 4,500 or less. [3] The polyisocyanate composition according to [1] or [2], wherein the alcohol (c) is either or both of a polyether polyol and a polyester polyol. [4] The polyisocyanate composition according to any one of [1] to [3], wherein the alcohol (c) comprises a polyether polyol, and the polyether polyol is a polyether polyol having at least one oxyalkylene group selected from the group consisting of an oxypropylene group and an oxytetramethylene group. [5] The polyisocyanate composition according to any one of [1] to [3], wherein the alcohol (c) contains a polyester polyol, and the polyester polyol is a polycaprolactone polyol. [6] The polyisocyanate composition according to any one of [1] to [5], wherein the molar fraction of allophanate groups relative to the total amount of isocyanurate groups and allophanate groups is 0.010 mol / mol or more and 0.700 mol / mol or less. [7] The polyisocyanate composition according to any one of [1] to [6], wherein the polyisocyanate contains a polyisocyanate (I) and a polyisocyanate (II), the polyisocyanate (I) is derived from the chain aliphatic diisocyanate (a) and the anionic compound (b), and the polyisocyanate (II) is derived from the chain aliphatic diisocyanate (a) and the alcohol (c). [8] The polyisocyanate composition according to [7], wherein the mass ratio of the polyisocyanate (I) to the polyisocyanate (II) [(I) / (II)] is 10 / 90 or more and 90 / 10 or less. [9] The polyisocyanate composition according to [7] or [8], wherein the polyisocyanate (I) includes a reaction product with the alcohol (c).

[10] The polyisocyanate composition according to any one of [1] to [9], which has a number average molecular weight of 500 or more and 3,000 or less.

[11] The polyisocyanate composition according to any one of [1] to

[10] , which has a viscosity at 25°C in the absence of an organic solvent of 500 mPa·s or more and 50,000 mPa·s or less.

[12] The polyisocyanate composition according to any one of [1] to

[11] , wherein the isocyanate group content is 8.0% by mass or more and 22.0% by mass or less.

[13] The polyisocyanate composition according to any one of [1] to

[12] , wherein the anionic compound (b) is one or more sulfonic acids selected from the group consisting of sulfonic acids containing a hydroxyl group and sulfonic acids containing an amino group.

[14] The polyisocyanate composition according to

[13] , wherein the sulfonic acid group of the anionic compound (b) is neutralized with an inorganic base or an organic amine compound.

[15] The polyisocyanate composition according to any one of [1] to

[14] , wherein the anionic compound (b) is a compound represented by the following general formula (1): [ka] (In general formula (1), R 11R is a hydrocarbon group having 1 to 10 carbon atoms which may contain at least one group selected from the group consisting of a hydroxyl group, an ether bond, an ester bond, a carbonyl group, and an imino group. 11 may contain a ring structure. The ring structure is an aromatic ring, a 5- or 6-membered ring containing two nitrogen atoms, or a 5- or 6-membered ring containing a nitrogen atom and an oxygen atom.

[16] A blocked polyisocyanate composition, in which the isocyanate groups of the polyisocyanate composition according to any one of [1] to

[15] are blocked with a thermally dissociable blocking agent.

[17] A coating composition comprising the polyisocyanate composition according to any one of [1] to

[15] or the blocked polyisocyanate composition according to

[16] .

[18] A coated substrate coated with the coating composition according to

[17] . [Effects of the Invention]

[0009] The polyisocyanate composition and blocked polyisocyanate composition of the above-mentioned aspects can provide polyisocyanate compositions and blocked polyisocyanate compositions that exhibit good dispersibility when blended with an aqueous base and that, when formed into a coating film, exhibit excellent gloss, water resistance, acid resistance, weather resistance, self-repairing properties, and adhesion. The coating composition of the above-mentioned aspect contains the polyisocyanate composition or the blocked polyisocyanate composition, and, when formed into a coating film, exhibits excellent gloss, water resistance, acid resistance, weather resistance, self-repairing properties, and adhesion. The coated substrate of the above-mentioned aspect is made of the coating composition, and the coating film provided on the coated substrate exhibits excellent gloss, water resistance, acid resistance, weather resistance, self-repairing properties, and adhesion. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of the present invention (hereinafter referred to as "the present embodiment") will be described in detail. The present invention is not limited to the following embodiments, and can be practiced in various modified forms within the scope of the invention.

[0011] <Polyisocyanate composition> The polyisocyanate composition of the present embodiment contains a polyisocyanate derived from a chain aliphatic diisocyanate (a) (hereinafter referred to as "diisocyanate (a)"), an anionic compound (b), and an alcohol (c). In one embodiment of the present invention, the polyisocyanate is the reaction product of a diisocyanate (a), an anionic compound (b), and an alcohol (c). The anionic compound (b) contains an active hydrogen group and has a mass fraction of 1.0% or more and 8.0% or less relative to the total mass of the polyisocyanate composition. The alcohol (c) has an average number of hydroxy groups per molecule of 1.0 or more and 6.0 or less, and a number average molecular weight of 100 or more and 7,000 or less. The polyisocyanate composition of the present embodiment contains an isocyanurate group and an allophanate group, and the molar fraction of the allophanate group relative to the total amount of the isocyanurate group and the allophanate group is 0.005 mol / mol or more and 0.850 mol / mol or less.

[0012] One aspect of the polyisocyanate composition of the present embodiment may contain a raw material polyisocyanate that has not reacted with the anionic compound (b), and an anionic compound that has not reacted with the raw material polyisocyanate. Furthermore, unless otherwise specified, the various physical properties or characteristics of the polyisocyanate composition of the present embodiment described below are characteristics that indicate a state in which the polyisocyanate obtained by the reaction of the raw material polyisocyanate with the anionic compound (hereinafter also referred to as a "modified polyisocyanate"), the unreacted raw material polyisocyanate, and the unreacted anionic compound are included.

[0013] The polyisocyanate composition of the present embodiment has the above-described configuration, and as will be shown in the examples described later, when blended with an aqueous base, it has good dispersibility, and when formed into a coating film, it provides a polyisocyanate composition that is excellent in gloss, water resistance, acid resistance, weather resistance, self-repairing property, and adhesion.

[0014] Each of the constituent components of the polyisocyanate composition of the present embodiment will be described in detail below.

[0015] <<Aliphatic chain diisocyanate (a) (diisocyanate (a))>> The polyisocyanate of the present embodiment has good dispersibility when the polyisocyanate composition is blended with an aqueous base resin, and contains a reaction product with a diisocyanate (a) in order to improve the gloss, water resistance, acid resistance, weather resistance, self-repairing property, and adhesion of the resulting coating film.

[0016] Examples of the diisocyanate (a) according to the present embodiment include, but are not limited to, 1,4-diisocyanatobutane, 1,5-diisocyanatopentane (hereinafter also referred to as "PDI"), ethyl (2,6-diisocyanato)hexanoate, 1,6-diisocyanatohexane (hereinafter also referred to as "HDI"), 1,9-diisocyanatononane, 1,12-diisocyanatododecane, 2,2,4- or 2,4,4-trimethyl-1,6-diisocyanatohexane, and the like.

[0017] The polyisocyanate of the present embodiment contains a reaction product with diisocyanate (a), and thus it is possible to provide a polyisocyanate composition that has good dispersibility when blended with a base agent and that has excellent self-repairing properties, adhesion, and weather resistance when formed into a coating film. Among these, as the diisocyanate (a), HDI and PDI are preferred in terms of the self-repairing property, adhesion, and weather resistance when formed into a coating film, and HDI is more preferred in terms of dispersibility when blended with the base agent and the self-repairing property and adhesion when formed into a coating film.

[0018] <Anionic compound (b)> The polyisocyanate of the present embodiment has good dispersibility when the polyisocyanate composition is blended into an aqueous base resin, and contains a reaction product with an anionic compound (b) in order to improve the gloss, water resistance, acid resistance, weather resistance, self-repairing property, and adhesion of the resulting coating film. The anionic compound (b) contains an active hydrogen group, and its mass fraction relative to the total mass of the polyisocyanate composition is 1.0% or more and 8.0% or less.

[0019] The anionic compound (b) is preferably one or more sulfonic acids selected from the group consisting of sulfonic acids containing a hydroxyl group and sulfonic acids containing an amino group.

[0020] The sulfonic acid group of the anionic compound (b) can be obtained by a neutralization reaction with one or more sulfonic acids selected from the group consisting of sulfonic acids containing a hydroxyl group and sulfonic acids containing an amino group.

[0021] The hydrophilic polyisocyanate compound contained in the polyisocyanate composition of the present embodiment has an anionic group derived from an anionic compound introduced into a portion of the isocyanate group.

[0022] When the anionic compound (b) is a sulfonic acid containing a hydroxyl group, examples thereof include a compound represented by the following general formula (1) (hereinafter abbreviated as "sulfonic acid (1)"). That is, in one embodiment of the present invention, the anionic compound is a compound represented by the following general formula (1):

[0023] [ka]

[0024] In the general formula (1), R 11 R is a hydrocarbon group having 1 to 10 carbon atoms which may contain at least one group selected from the group consisting of a hydroxyl group, an ether bond, an ester bond, a carbonyl group, and an imino group. 11 may contain a ring structure, which is an aromatic ring, a five- or six-membered ring containing two nitrogen atoms, or a five- or six-membered ring containing a nitrogen atom and an oxygen atom.

[0025] The hydrocarbon group having from 1 to 10 carbon atoms may be a divalent aliphatic hydrocarbon group having from 1 to 10 carbon atoms, or may be a divalent aromatic hydrocarbon group having from 6 to 10 carbon atoms. The divalent aliphatic hydrocarbon group having from 1 to 10 carbon atoms is preferably a chain alkylene group having from 1 to 6 carbon atoms. When the chain alkylene group has from 1 to 6 carbon atoms, the chain alkylene group may have a ring structure as part of it. The alkylene group having from 1 to 6 carbon atoms may be linear or branched.

[0026] Among them, R 11 is preferably a chain-like alkylene group having from 1 to 6 carbon atoms, a divalent aromatic hydrocarbon group (arylene group) having from 6 to 10 carbon atoms, a divalent alkylene group having from 1 to 6 carbon atoms and containing an aromatic ring, a divalent alkylene group having from 1 to 6 carbon atoms and containing a 5- or 6-membered ring containing two nitrogen atoms, or a divalent alkylene group having from 1 to 6 carbon atoms and containing a 5- or 6-membered ring containing a nitrogen atom and an oxygen atom.

[0027] Preferred examples of the anionic compound (b) having a hydroxyalkylsulfonic acid group include 2-hydroxyethanesulfonic acid, 3-hydroxypropanesulfonic acid, 4-hydroxybutanesulfonic acid, 5-hydroxypentanesulfonic acid, 6-hydroxyhexanesulfonic acid, hydroxybenzenesulfonic acid, hydroxy(methyl)benzenesulfonic acid, 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid, 4-(2-hydroxyethyl)-1-piperazinepropanesulfonic acid, and 2-hydroxy-3-morpholinopropanesulfonic acid. These compounds are merely a part of the preferred sulfonic acid (1), and the preferred sulfonic acid (1) is not limited to these. These sulfonic acids (1) may be used alone or in combination of two or more.

[0028] Among these, the anionic compound (b) having a hydroxy group is preferably at least one selected from the group consisting of 2-hydroxyethanesulfonic acid, 3-hydroxypropanesulfonic acid, hydroxybenzenesulfonic acid, and hydroxy(methyl)benzenesulfonic acid. These anionic compounds having a hydroxyalkylsulfonic acid provide a curing agent with good chromaticity and a coating film with good gloss.

[0029] When the polyisocyanate composition of the present embodiment contains two or more types of amine salts of sulfonic acid, the sulfonic acids (1) may be the same or different.

[0030] The sulfonic acid used in the polyisocyanate containing a sulfonate anion group in the molecule may form a salt with an amine compound described below.

[0031] When the anionic compound (b) is a sulfonic acid having an amino group, examples thereof include a compound represented by the following general formula (2) (hereinafter abbreviated as "sulfonic acid (2)"). That is, in one embodiment of the present invention, the anionic compound is a compound represented by the following general formula (2):

[0032] [ka]

[0033] In the general formula (2), R 21 and R 23 are each independently a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms which may contain a hydroxyl group. 21 and R 23 At least one of R is a hydrogen atom. 22 is a hydrocarbon group having 1 to 12 carbon atoms which may contain a hydroxyl group.

[0034] ·R 21 and R 23 In general formula (2), R 21 and R23 are each independently a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms which may contain a hydroxyl group. 21 and R 23 may be the same or different. 21 and R 23 At least one of R is a hydrogen atom. 21 is a hydrocarbon group having 1 to 12 carbon atoms which may contain a hydroxyl group, R 23 is a hydrogen atom. 23 is a hydrocarbon group having 1 to 12 carbon atoms which may contain a hydroxyl group, R 21 is a hydrogen atom. 21 and R 23 Any of these may be a hydrogen atom.

[0035] The hydrocarbon group having from 1 to 12 carbon atoms may be a monovalent aliphatic hydrocarbon group having from 1 to 12 carbon atoms, or may be a monovalent aromatic hydrocarbon group having from 6 to 12 carbon atoms. The monovalent aliphatic hydrocarbon group having from 1 to 12 carbon atoms is preferably a chain alkyl group having from 1 to 6 carbon atoms, or a cyclic alkyl group having from 3 to 6 carbon atoms. The chain alkyl group having from 1 to 6 carbon atoms may be linear or branched.

[0036] Among them, R 21 and R 23 are preferably a hydrogen atom, a chain alkyl group having 1 to 6 carbon atoms, or a cyclic alkyl group having 3 to 6 carbon atoms.

[0037] ·R 22 R 22 is a hydrocarbon group having 1 to 12 carbon atoms which may contain a hydroxyl group. The hydrocarbon group having from 1 to 12 carbon atoms may be a divalent aliphatic hydrocarbon group having from 1 to 12 carbon atoms, or may be a divalent aromatic hydrocarbon group having from 6 to 12 carbon atoms. The divalent aliphatic hydrocarbon group having from 1 to 12 carbon atoms is preferably a chain alkylene group having from 1 to 12 carbon atoms. The chain alkyl group having from 1 to 12 carbon atoms may be linear or branched. Among them, R 22 is preferably a divalent chain alkylene group having 1 to 6 carbon atoms, or a divalent aromatic hydrocarbon group (arylene group) having 6 to 10 carbon atoms.

[0038] Preferred examples of the sulfonic acid (2) include 2-aminoethanesulfonic acid, 3-aminopropanesulfonic acid, 2-methylaminoethanesulfonic acid, 3-methylaminopropanesulfonic acid, 2-cyclohexylaminoethanesulfonic acid, 3-cyclohexylaminopropanesulfonic acid, 3-cyclohexylaminoisobutylsulfonic acid, 4-cyclohexylaminobutanesulfonic acid, 2-cyclohexylmethylaminoethanesulfonic acid, 3-cyclohexylmethylaminopropanesulfonic acid, 3-cyclohexylmethylaminoisobutylsulfonic acid, 4-cyclohexylmethylaminobutanesulfonic acid, 2-methylcyclohexylaminoethanesulfonic acid, 3-methylcyclohexylaminopropanesulfonic acid, 3-methylcyclohexylaminoisobutylsulfonic acid, 4-methylcyclohexylaminobutanesulfonic acid, 2 dimethylcyclohexylaminoethanesulfonic acid, 3-dimethylcyclohexylaminopropanesulfonic acid, 3-dimethylcyclohexylaminoisobutylsulfonic acid, 4-dimethylcyclohexylaminobutanesulfonic acid, 2-trimethylcyclohexylaminoethanesulfonic acid, 3-trimethylcyclohexylaminopropanesulfonic acid, 3-trimethylcyclohexylaminoisobutylsulfonic acid, 4-trimethylcyclohexylaminobutanesulfonic acid, 2-aminobenzenesulfonic acid, 3-aminobenzenesulfonic acid, 4-aminobenzenesulfonic acid, 2-(methylamino)benzenesulfonic acid, 3-(methylamino)benzenesulfonic acid, 4-(methylamino)benzenesulfonic acid, amino-methylbenzenesulfonic acid, amino-dimethylbenzenesulfonic acid, aminonaphthalenesulfonic acid, and the like. These compounds are merely a part of the preferred sulfonic acids (2), and the preferred sulfonic acids (2) are not limited to these. These sulfonic acids (2) may be used alone or in combination of two or more.

[0039] Among these, the sulfonic acid having an amino group is preferably at least one selected from the group consisting of 2-cyclohexylaminoethanesulfonic acid, 3-cyclohexylaminopropanesulfonic acid, 4-cyclohexylaminobutanesulfonic acid, 3-cyclohexylmethylaminopropanesulfonic acid, 3-(p-methylcyclohexylamino)propanesulfonic acid, 3-(3,3,5-trimethylcyclohexylamino)propanesulfonic acid, 4-(p-methylcyclohexylamino)butanesulfonic acid, 2-aminobenzenesulfonic acid, 2-amino-5-methylbenzenesulfonic acid, 2-amino-3,5-dimethylbenzenesulfonic acid, 5-amino-2-methylbenzenesulfonic acid (4-aminotoluene-2-sulfonic acid), 4-amino-2-methylbenzenesulfonic acid (5-aminotoluene-2-sulfonic acid), and 2-aminonaphthalene-4-sulfonic acid.

[0040] In one embodiment of the present invention, the sulfonic acid group of the anionic compound (b) is preferably neutralized with an inorganic base or an organic amine compound.

[0041] Examples of the organic amine compound include linear tertiary amines such as trimethylamine, triethylamine, tripropylamine, tributylamine, trioctylamine, trilaurylamine, tritridecylamine, and tristearylamine; branched tertiary amines such as triisopropylamine, triisobutylamine, tri-2-ethylhexylamine, and tribranched tridecylamine; N,N-dimethylethylamine, N,N-dimethylpropylamine, N,N-dimethylisopropylamine, N,N-dimethylbutylamine, and N,N-dimethylisobutylamine; N,N-Dimethyloctylamine, N,N-Dimethyl-2-ethylhexylamine, N,N-Dimethyllaurylamine, N,N-Dimethyl(branched)tridecylamine, N,N-Dimethylstearylamine, N,N-Diethylbutylamine, N,N-Diethylhexylamine, N,N-Diethyloctylamine, N,N-Diethyl-2-ethylhexylamine, N,N-Diethyllaurylamine, N,N-Diisopropylmethylamine, N,N-Diisopropylethylamine, N,N-Diisopropylbutylamine, N,N-Diisopropyl-2-ethyl tertiary amines having mixed hydrocarbon groups such as N,N-dimethylcyclohexylamine, N,N-diethylbenzylamine, N,N-diethylcyclohexylamine, N,N-dicyclohexylmethylamine, N,N-dicyclohexylethylamine, tricyclohexylamine; alicyclic tertiary amines such as N,N-dimethylbenzylamine, N,N-diethylbenzylamine, N,N-dibenzylmethylamine, tribenzylamine, N,N-dimethyl-4-methylbenzylamine, N,N-dimethylphenylamine, N,N-di Examples thereof include tertiary amines having an aromatic ring substituent, such as ethylphenylamine and N,N-diphenylmethylamine; and cyclic amines, such as N-methylpyrrolidine, N-ethylpyrrolidine, N-propylpyrrolidine, N-butylpyrrolidine, N-methylpiperidine, N-ethylpiperidine, N-propylpiperidine, N-butylpiperidine, N-methylmorpholine, N-ethylmorpholine, N-propylmorpholine, N-butylmorpholine, N-sec-butylmorpholine, N-tert-butylmorpholine, N-isobutylmorpholine, and quinuclidine.These organic amine compounds may be used alone or in combination of two or more.

[0042] Among these, tertiary amines having 5 to 30 carbon atoms are preferred, and specific examples thereof include triethylamine, tripropylamine, tributylamine, trioctylamine, trilaurylamine, tridecylamine, triisopropylamine, triisobutylamine, tri-2-ethylhexylamine, tri-branched tridecylamine, N,N-dimethylpropylamine, N,N-dimethylisopropylamine, N,N-dimethylbutylamine, N,N-dimethylisobutylamine, N,N-dimethyloctylamine, N,N-dimethyl-2-ethylhexylamine, N,N-dimethyllaurylamine, N,N-dimethyl(branched)tridecylamine, N,N-dimethylstearylamine, N,N-diethylbutylamine, N,N-diethylhexylamine, and N,N-dimethylisopropylamine. Examples of the organic amine compounds include diethyloctylamine, N,N-diethyl-2-ethylhexylamine, N,N-diethyllaurylamine, N,N-diisopropylmethylamine, N,N-diisopropylethylamine, N,N-dimethylcyclohexylamine, N,N-diethylcyclohexylamine, N,N-dicyclohexylmethylamine, N,N-dicyclohexylethylamine, N,N-dimethylbenzylamine, N,N-diethylbenzylamine, N,N-dibenzylmethylamine, tribenzylamine, N,N-dimethylphenylamine, N,N-diethylphenylamine, N,N-diphenylmethylamine, N-methylpiperidine, N-ethylpiperidine, N-methylmorpholine, N-ethylmorpholine, quinuclidine, pyridine, and quinoline. These preferred organic amine compounds may be used alone or in combination of two or more.

[0043] When the polyisocyanate composition of the present embodiment contains two or more types of amine salts of sulfonic acid, the sulfonic acids (2) may be the same or different.

[0044] Anionic compounds containing active hydrogen groups such as hydroxyl groups or amino groups have high emulsifying power, so that a high emulsifying effect can be obtained with a small amount. When polyisocyanate is modified with an anionic compound (b) (by introducing hydrophilic groups derived from a hydrophilic compound into the polyisocyanate) to disperse it in water, only a small amount of the anionic compound is required, so the modification rate does not become too high and the physical properties of the coating film (gloss and acid resistance) are less likely to deteriorate.

[0045] In the polyisocyanate composition of this embodiment, the mass fraction of the anionic compound (b) relative to the total mass of the polyisocyanate composition is 1.0 mass% or more and 8.0 mass% or less. The mass fraction of the anionic compound (b) is preferably 2.0 mass% or more, more preferably 3.0 mass% or more, from the viewpoints of further improving dispersibility when blended with the base agent and gloss when formed into a coating film. Furthermore, the mass fraction of the anionic compound (b) is more preferably 7.6 mass% or less, even more preferably 7.2 mass% or less, from the viewpoints of further improving dispersibility when blended with the base agent and water resistance and acid resistance when formed into a coating film.

[0046] In one embodiment of the present invention, the mass fraction of the anionic compound (b) relative to the total mass of the polyisocyanate composition is preferably 2.0 mass % or more and 7.6 mass % or less, and more preferably 3.0 mass % or more and 7.2 mass % or less.

[0047] (Method for producing anionic compound (b)) The neutralized salt of the acidic group bonded to the anionic compound (b) used in the polyisocyanate composition of the present embodiment can be obtained by neutralization with a cationic compound such as the inorganic base or organic amine compound described above. Furthermore, when the neutralized salt is an amine salt of sulfonic acid, it can be obtained, for example, by mixing a compound containing a sulfonic acid group with an amine compound and neutralizing the mixture.

[0048] The neutralization reaction may be carried out before or simultaneously with the reaction with the diisocyanate or polyisocyanate, or may be carried out by adding an amine compound after the reaction of the polyisocyanate compound with the compound containing a sulfonic acid group.

[0049] When the active hydrogen group is a hydroxyl group, the neutralization reaction is preferably carried out in advance before the reaction with a polyisocyanate compound. When the active hydrogen group is an amino group, the neutralization reaction is preferably carried out simultaneously with the reaction with a polyisocyanate compound, or by adding an amine compound after the reaction of a polyisocyanate compound with a sulfonic acid having an active hydrogen group.

[0050] When the active hydrogen group is a hydroxyl group, the ratio of mixing the sulfonic acid having a hydroxyl group and the amine compound in the neutralization reaction is preferably such that the molar ratio of the amine compound to the sulfonic acid having a hydroxyl group (molar ratio of amine compound / sulfonic acid having a hydroxyl group) is 0.5 or more and 2.0 or less, more preferably 0.8 or more and 1.5 or less.

[0051] When the neutralization reaction is carried out in advance, the temperature and time are appropriately determined depending on the progress of the reaction, but the temperature is usually preferably about 0°C or higher and 100°C or lower, and the mixing time is preferably about 10 minutes or higher and 24 hours or lower.

[0052] The solvent used in preparing the amine salt of the compound containing a sulfonic acid group is preferably water or a hydrophilic solvent. The hydrophilic solvent is not particularly limited, but examples thereof include alcohols, ether alcohols, ketones, and amide solvents. These solvents can be used alone or in combination.

[0053] Examples of alcohols include methanol, ethanol, propanol, butanol, and isopropanol.

[0054] Examples of the ether alcohols include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, and dipropylene glycol monomethyl ether.

[0055] Examples of ketones include acetone, methyl ethyl ketone, and methyl isobutyl ketone.

[0056] Examples of the amide solvent include N,N-dimethylformamide and N,N-dimethylacetamide.

[0057] After the neutralization reaction, it is preferable to remove the water or hydrophilic solvent.

[0058] <Alcohol (c)> The polyisocyanate of the present embodiment contains a reaction product with an alcohol (c) in order to improve dispersibility when the polyisocyanate composition is blended with a base agent, and the self-repairing properties, adhesion, and weather resistance of a coating film when formed into the coating film. In the polyisocyanate composition of the present embodiment, the alcohol (c) has an average number of hydroxyl groups per molecule of 1.0 or more and 6.0 or less, and a number average molecular weight of 100 or more and 7,000 or less.

[0059] Alcohols satisfying the above average number of hydroxyl groups and number average molecular weight include monools, diols, triols, tetraols, polymerized alcohols, etc. Monools are monoalcohols having 8 to 20 carbon atoms, such as 1-octanol, 2-ethyl-1-hexanol, 3,3,5-trimethyl-1-hexanol, and tridecanol, and diols are 1,3-butanediol, 1,5-pentanediol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol, neopentyl glycol, 2-methyl-2,3-butanediol, 1,6-hexanediol, 1,2-hexanediol, and 2,5-hexanediol. ethanol, 2-methyl-2,4-pentanediol, 2,3-dimethyl-2,3-butanediol, 3-methyl-1,5-pentanediol, 2-ethyl-hexanediol, 1,2-octanediol, 2-methyl-1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,2-decanediol, 2,2,4-trimethylpentanediol, 2-butyl-2-ethyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, and the like.

[0060] Examples of polymerized alcohols include polyester polyols, polyether polyols, polyolefin polyols, and polycarbonate diols. Polyether polyols include polyether polyols obtained by random or block addition of alkylene oxides (e.g., ethylene oxide, propylene oxide, butylene oxide, cyclohexene oxide, styrene oxide) alone or in combination with polyhydric hydroxy compounds (e.g., polyamines) using strong basic catalysts (e.g., hydroxides of lithium, sodium, or potassium, alcoholates, or alkylamines), or composite metal cyanide complexes (e.g., metalloporphyrins or zinc hexacyanocobaltate complexes), polyether polyols obtained by reacting alkylene oxides with polyamine compounds (e.g., ethylenediamines), and so-called polymer polyols obtained by polymerizing acrylamide or the like using these polyethers as a medium. Commercially available polyether polyols include those manufactured by AGC Inc. under the trade names "Excenol 510" and "Excenol 840," and those manufactured by Hodogaya Chemical Co., Ltd. under the trade names "PTG-250" and "PTG-1000."

[0061] Examples of polyester polyols include polyester polyols obtained by a condensation reaction of a dibasic acid selected from the group consisting of carboxylic acids such as succinic acid, adipic acid, sebacic acid, dimer acid, maleic anhydride, phthalic anhydride, isophthalic acid, and terephthalic acid, alone or in combination, with a polyhydric alcohol selected from the group consisting of ethylene glycol, propylene glycol, diethylene glycol, neopentyl glycol, trimethylolpropane, and glycerin, alone or in combination, and polycaprolactones obtained by ring-opening polymerization of ε-caprolactone with a polyhydric alcohol. Among these, polycaprolactone is preferred from the viewpoint of improving water resistance and weather resistance. Commercially available polycaprolactone polyols include the PLACCEL 300 series manufactured by Daicel Corporation, trade names of which include PLACCEL 303, PLACCEL 305, PLACCEL 308, and PLACCEL 312.

[0062] These alcohols (c) may be used alone or in combination. From the viewpoint of improving the self-repairing property, acid resistance, and weather resistance of a coating film formed therefrom, either one or both of polyether polyols and polyester polyols are preferred, and from the viewpoint of improving the acid resistance and weather resistance of a coating film formed therefrom, polyester polyols are more preferred.

[0063] When the alcohol (c) contains a polyether polyol, the polyether polyol is preferably a polyether polyol having an oxyalkylene group, from the viewpoint of improving the self-repairing property, acid resistance, and weather resistance of the resulting coating film. The polyether polyol having an oxyalkylene group is a polyether polyol having an oxyalkylene group in the molecular chain. In this case, the oxyalkylene repeating unit may have other oxyalkylene groups, specifically, oxyethylene groups, oxytetramethylene groups, oxycyclohexyl groups, or oxystyrene groups, and is preferably a polyether polyol having at least one oxyalkylene group selected from the group consisting of oxypropylene groups and oxytetramethylene groups.

[0064] When the alcohol (c) contains a polyester polyol, the polyester polyol is preferably a polycaprolactone polyol from the viewpoint of improving the self-repairing property, acid resistance, and weather resistance of the coating film formed therefrom.

[0065] In the polyisocyanate composition of the present embodiment, the alcohol (c) preferably has an average number of hydroxyl groups per molecule of 2.0 or more and 4.0 or less, and a number average molecular weight of 100 or more and 4,500 or less, from the viewpoint of improving the self-repairing property, adhesion, and weather resistance of a coating film formed therefrom.

[0066] <Polyisocyanate> The polyisocyanate of the present embodiment is not particularly limited as long as the entire polyisocyanate composition contains an isocyanurate group and an allophanate group, and examples thereof include mixtures of polyisocyanates shown in the following (a1) to (h1). (a1) a polyisocyanate having a uretdione group obtained by cyclodimerization of two isocyanate groups; (b1) Polyisocyanates having isocyanurate groups or iminooxadiazinedione groups obtained by cyclotrimerization of three isocyanate groups; (c1) Polyisocyanates containing biuret groups obtained by reacting three isocyanate groups with one water molecule; (d1) Polyisocyanate having an oxadiazinetrione group obtained by reacting two isocyanate groups with one molecule of carbon dioxide; (e1) Polyisocyanate having a plurality of urethane groups obtained by reacting one isocyanate group with one hydroxyl group; (f1) Polyisocyanates having allophanate groups obtained by reacting two isocyanate groups with one hydroxyl group; (g1) Polyisocyanates having an acylurea group obtained by reacting one isocyanate group with one carboxyl group; (h1) Polyisocyanates having urea groups obtained by reacting one isocyanate group with one primary or secondary amine.

[0067] Among these, the polyisocyanate used for the polyisocyanate containing an anionic compound in the molecule is preferably the above (b1), and more preferably a polyisocyanate having an isocyanurate group.

[0068] (isocyanurate group) The isocyanurate group is a functional group obtained by cyclic trimerization of three isocyanate groups, and has a structure represented by the following formula (3).

[0069] [ka]

[0070] The content of each structure derived from an isocyanate group is: 13 Specifically, the C-NMR measurement was performed using Biospin Avance600 (trade name) manufactured by Bruker. 13 In C-NMR measurements (measurement solvent: chloroform-d, sample concentration: 60 mass / volume%, observation frequency: 150 MHz, number of accumulations: 10,000), when the chain aliphatic diisocyanate is HDI, the isocyanurate ring structure exhibits a signal from the carbon atom of the carbonyl group in the six-membered ring at around 148.6 ppm. Since there are three identical carbon atoms in the structure, 1 / 3 of the integral value corresponds to the mole fraction of the structure.

[0071] (allophanate group) The allophanate group is a functional group formed by the reaction of a hydroxyl group with an isocyanate group, and has a structure represented by the following formula (4).

[0072] [ka]

[0073] (allophanate mole fraction) In the polyisocyanate composition of this embodiment, the molar fraction of allophanate groups relative to the total amount of isocyanurate groups and allophanate groups is 0.005 mol / mol or more and 0.850 mol / mol or less, and preferably 0.010 mol / mol or more and 0.700 mol / mol or less. When the molar fraction of the allophanate group is within the above range, the resulting coating composition tends to have excellent dispersibility in the base agent, and the resulting coating film tends to have excellent water resistance, acid resistance, self-repairing property, adhesion, and weather resistance. The mole fraction of allophanate groups is, for example, 13 It can be determined by C-NMR measurement.

[0074] (Other bonding groups) The polyisocyanate composition of the present embodiment may further have, in addition to the above-described bonding groups, one or more bonding groups selected from the group consisting of a urethane group, a biuret group, a urea group, an acylurea group, and an oxadiazinetrione group.

[0075] <Polyisocyanate> In one embodiment of the present invention, the polyisocyanate composition comprises one or more polyisocyanates derived from raw materials that all contain a diisocyanate (a), an anionic compound (b), and an alcohol (c). In one embodiment of the present invention, the polyisocyanate composition comprises one or more polyisocyanates (I) derived from a diisocyanate (a) and an anionic compound (b), and one or more polyisocyanates (II) derived from the diisocyanate (a) and an alcohol (c).

[0076] In this case, the mass ratio of polyisocyanate (I) to polyisocyanate (II) [(I) / (II)] is preferably 10 / 90 or more and 90 / 10 or less, and more preferably 15 / 85 or more and 85 / 15 or less. When the polyisocyanate composition has this composition, the water resistance, acid resistance, and weather resistance of the coating film formed therefrom tend to be better.

[0077] The polyisocyanate (I) may also contain a reaction product with the alcohol (c). When the polyisocyanate composition contains a reaction product with the alcohol (c), the water resistance, acid resistance, and weather resistance tend to be improved.

[0078] (Physical properties of polyisocyanate (I)) The viscosity of the polyisocyanate (I) at 25°C without containing any organic solvent is preferably 1,000 mPa·s or more and 50,000 mPa·s or less, from the viewpoints of improving dispersibility in the base resin and improving the appearance and water resistance of the formed coating film.

[0079] The lower limit of the viscosity is more preferably 1,500 mPa·s, and even more preferably 2,000 mPa·s, from the viewpoint of improving the acid resistance of the cured coating film, while the upper limit of the viscosity is more preferably 35,000 mPa·s, and even more preferably 20,000 mPa·s, from the viewpoint of improving dispersibility and facilitating dilution with a solvent.

[0080] The viscosity can be measured by the method described in the Examples below [Physical Properties 1: Viscosity].

[0081] The isocyanate group content (NCO%) of the polyisocyanate (I), excluding unreacted diisocyanate, is preferably 12% by mass or more and 22% by mass or less, more preferably 14% by mass or more and 20% by mass or less, and even more preferably 14% by mass or more and 20% by mass or less.

[0082] When the isocyanate group content is equal to or greater than the lower limit, the water resistance, acid resistance, and weather resistance of the coating film formed are improved, whereas when the isocyanate group content is equal to or less than the upper limit, the dispersibility and solvent dilutability of the coating composition are improved, resulting in a better appearance of the coating film formed.

[0083] The isocyanate group content (NCO%) can be measured by the method described in the Examples below [Property 2: Isocyanate group content (NCO%)].

[0084] From the viewpoint of making the polyisocyanate have a viscosity that is easy to handle and to disperse in a coating liquid, the number average molecular weight of the polyisocyanate (I) is preferably from 450 to 2,000, more preferably from 500 to 1,800, and even more preferably from 550 to 1,500. The number average molecular weight can be measured, for example, using gel permeation chromatography (GPC).

[0085] (Physical properties of polyisocyanate (II)) The viscosity of the polyisocyanate (II) at 25°C without containing an organic solvent is preferably 500 mPa·s or more and 50,000 mPa·s or less, from the viewpoints of improving dispersibility in the base resin and improving the appearance and water resistance of a coating film formed therefrom.

[0086] The lower limit of the viscosity is more preferably 750 mPa·s, and even more preferably 1,000 mPa·s, from the viewpoint of improving the acid resistance of the cured coating film, while the upper limit of the viscosity is more preferably 35,000 mPa·s, and even more preferably 20,000 mPa·s, from the viewpoint of improving dispersibility and solvent dilutability.

[0087] The viscosity can be measured by the method described in the Examples below [Physical Properties 1: Viscosity].

[0088] The isocyanate group content (NCO%) of the polyisocyanate (II), excluding unreacted diisocyanate, is preferably 6% by mass or more and 22% by mass or less, more preferably 8% by mass or more and 20% by mass or less.

[0089] When the isocyanate group content is equal to or greater than the above lower limit, the water resistance, acid resistance, and weather resistance of the resulting coating film are improved, whereas when the isocyanate group content is equal to or less than the above upper limit, the self-repairing properties and adhesion of the resulting coating film are improved.

[0090] The isocyanate group content (NCO%) can be measured by the method described in the Examples below [Property 2: Isocyanate group content (NCO%)].

[0091] From the viewpoint of making the viscosity of the polyisocyanate easy to handle and easy to disperse in a coating liquid, the number average molecular weight of the polyisocyanate (II) is preferably from 450 to 2,000, more preferably from 500 to 1,800, and even more preferably from 550 to 1,500. The number average molecular weight can be measured, for example, using gel permeation chromatography (GPC).

[0092] <Method for producing polyisocyanates having each bonding group> (Method for producing polyisocyanate containing isocyanurate groups) The catalyst for deriving a polyisocyanate containing an isocyanurate group from a diisocyanate is not particularly limited, but is preferably a catalyst that exhibits basicity, and examples thereof include tetraalkylammonium hydroxides and weak organic acid salts, hydroxyalkylammonium hydroxides and weak organic acid salts, alkali metal salts of alkylcarboxylic acids, metal alcoholates, aminosilyl group-containing compounds, Mannich bases, combined use of tertiary amines and epoxy compounds, and phosphorus-based compounds.

[0093] Examples of the tetraalkylammonium include tetramethylammonium and tetraethylammonium.

[0094] Examples of organic weak acids include acetic acid and capric acid.

[0095] Examples of hydroxyalkylammonium include trimethylhydroxypropylammonium, trimethylhydroxyethylammonium, triethylhydroxypropylammonium, and triethylhydroxyethylammonium.

[0096] Examples of the alkylcarboxylic acid include acetic acid, caproic acid, octylic acid, and myristic acid.

[0097] Examples of the alkali metal salt include tin, zinc, and lead.

[0098] Examples of the metal alcoholate include sodium alcoholate and potassium alcoholate.

[0099] Examples of the aminosilyl group-containing compound include hexamethyldisilazane.

[0100] Examples of phosphorus compounds include tributylphosphine.

[0101] The amount of these catalysts used is preferably 10 ppm by mass or more and 10,000 ppm by mass or less based on the total mass of the diisocyanate (and, if necessary, alcohol) that is the raw material. To terminate the isocyanurate-forming reaction, the catalyst may be inactivated by adding an acidic substance that neutralizes the catalyst, or by thermal decomposition, chemical decomposition, or the like. Examples of acidic substances that neutralize the catalyst include phosphoric acid and acidic phosphate esters.

[0102] The yield of polyisocyanate generally tends to be 10% by mass or more and 70% by mass or less. Polyisocyanate obtained with a higher yield tends to have a higher viscosity. The yield can be calculated from the ratio of the mass of the obtained polyisocyanate to the total mass of the raw material components.

[0103] The reaction temperature for the isocyanurate reaction is not particularly limited, but is preferably from 50° C. to 200° C., and more preferably from 50° C. to 150° C. When the reaction temperature is equal to or higher than the lower limit, the reaction tends to proceed more easily, and when the reaction temperature is equal to or lower than the upper limit, side reactions that cause coloration tend to be more effectively suppressed.

[0104] After completion of the isocyanurate reaction, it is preferable to remove unreacted diisocyanate using a thin film evaporator, extraction, or the like. Even if the polyisocyanate contains unreacted diisocyanate, the diisocyanate content is preferably 3.0 mass% or less, more preferably 1.0 mass% or less, and even more preferably 0.5 mass% or less, based on the total mass of the polyisocyanate. When the concentration of residual unreacted diisocyanate is within the above range, curability tends to be better.

[0105] The concentration of residual unreacted diisocyanate is preferably 0% by mass. That is, the concentration of residual unreacted diisocyanate is preferably 0% by mass or more and 3.0% by mass or less, more preferably 0% by mass or more and 1.0% by mass or less, and even more preferably 0% by mass or more and 0.5% by mass or less.

[0106] (Method for producing polyisocyanates containing allophanate groups) The catalyst for deriving an allophanate group-containing polyisocyanate from a diisocyanate is not particularly limited, and examples thereof include alkylcarboxylates of tin, lead, zinc, bismuth, zirconium, zirconyl, etc.; organic tin compounds such as tin 2-ethylhexanoate and dibutyltin dilaurate; organic lead compounds such as lead 2-ethylhexanoate; organic zinc compounds such as zinc 2-ethylhexanoate; bismuth 2-ethylhexanoate, zirconium 2-ethylhexanoate, and zirconyl 2-ethylhexanoate. These can be used alone or in combination of two or more.

[0107] Furthermore, the above-mentioned isocyanuration reaction catalyst can also serve as an allophanation reaction catalyst. When the above-mentioned isocyanuration reaction catalyst is used to carry out an allophanation reaction, an isocyanurate group-containing polyisocyanate is naturally also produced. From the viewpoint of economical production, it is preferable to carry out the allophanation reaction and the isocyanurate reaction using the above-mentioned isocyanuration reaction catalyst as the allophanation reaction catalyst.

[0108] The amount of the allophanate formation reaction catalyst blended is preferably 10 ppm by mass or more and 1000 ppm by mass or less, relative to the mass of the charged diisocyanate. The lower limit is more preferably 20 ppm by mass, even more preferably 40 ppm by mass, and even more preferably 80 ppm by mass. The upper limit is more preferably 800 ppm by mass, even more preferably 600 ppm by mass, and even more preferably 500 ppm by mass or less.

[0109] The amount of the allophanate reaction catalyst added is, for example, 20 to 800 ppm by mass, 40 to 600 ppm by mass, or 80 to 500 ppm by mass, relative to the mass of the charged diisocyanate.

[0110] The allophanatization reaction temperature is preferably 40° C. or higher and 180° C. or lower. The lower limit is more preferably 60° C., even more preferably 80° C., and still more preferably 100° C. The upper limit is more preferably 160° C., and even more preferably 140° C. By keeping the allophanate reaction temperature at or above the above lower limit, it tends to be possible to maintain a higher reaction rate. By keeping the allophanate reaction temperature at or below the above upper limit, it tends to be possible to more effectively suppress coloration of the polyisocyanate.

[0111] The allophanatization reaction temperature is, for example, 80°C or higher and 160°C or lower, or 100°C or higher and 140°C or lower.

[0112] The alcohol used to form the allophanate group is preferably an alcohol formed only from carbon, hydrogen and oxygen.

[0113] In the method for producing a polyisocyanate composition of the present embodiment, a solvent may or may not be used. The solvent used in the method for producing a polyisocyanate composition of the present embodiment may be a hydrophilic solvent or a hydrophobic solvent. Examples of hydrophobic solvents include mineral spirits, solvent naphtha, LAWS (Low Aromatic White Spirit), HAWS (High Aromatic White Spirit), toluene, xylene, cyclohexane, etc.; esters such as ethyl acetate and butyl acetate; and ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone.

[0114] Examples of hydrophilic solvents include alcohols such as methanol, ethanol, propanol, isopropanol, and 2-ethylhexanol; ethers such as diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, and dipropylene glycol dimethyl ether; and esters of ether alcohols such as ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, and dipropylene glycol monomethyl ether acetate. These may be used alone or in combination.

[0115] ≪Viscosity≫ The viscosity of the polyisocyanate composition of this embodiment at 25°C without containing an organic solvent is preferably 500 mPa·s or more and 50,000 mPa·s or less, from the viewpoint of making the polyisocyanate composition easy to handle and easy to disperse in a coating liquid. The lower limit of the viscosity is more preferably 750 mPa·s, and even more preferably 1,000 mPa·s, from the viewpoint of improving the acid resistance, etc., of the cured coating film. On the other hand, the upper limit of the viscosity is more preferably 35,000 mPa·s, and even more preferably 20,000 mPa·s, from the viewpoint of suppressing viscosity change during blending. The viscosity can be measured by the method described in the Examples [Property 1: Viscosity] below.

[0116] The above upper and lower limits of the viscosity of the polyisocyanate composition can be combined in any desired manner. Combinations include 500 mPa·s or more and 350,000 mPa·s or less, and 750 mPa·s or more and 20,000 mPa·s or less.

[0117] <Isocyanate group content> The isocyanate group content (NCO%) of the polyisocyanate composition is preferably 8.0% by mass or more and 22.0% by mass or less, and more preferably 10.0% by mass or more and 20.0% by mass or less.

[0118] When the isocyanate group content is equal to or greater than the lower limit, the water resistance, acid resistance, and weather resistance of the coating film formed are likely to be improved. On the other hand, when the isocyanate group content is equal to or less than the upper limit, the dispersibility and solvent dilutability of the coating composition are improved, resulting in a better appearance of the coating film formed. The isocyanate group content (NCO%) can be measured by the method described in the Examples below [Property 2: Isocyanate Group Content (NCO%)].

[0119] ≪Number average molecular weight≫ The number average molecular weight of the polyisocyanate composition is preferably from 500 to 3,000, more preferably from 500 to 2,500, and even more preferably from 600 to 2,000, from the viewpoints of ease of handling the polyisocyanate composition, ease of dispersing it in a coating liquid, and weather resistance when formed into a coating film. The number average molecular weight can be measured, for example, using gel permeation chromatography (GPC).

[0120] <Blocked polyisocyanate composition> The blocked polyisocyanate composition of the present embodiment contains a blocked polyisocyanate in which the isocyanate groups of the polyisocyanate composition in the above-described <Polyisocyanate Composition> are blocked with a thermally dissociable blocking agent. In one embodiment of the present invention, the blocked polyisocyanate is a reaction product of a diisocyanate (a), an anionic compound (b), and an alcohol (c).

[0121] One aspect of the blocked polyisocyanate composition of the present embodiment may contain a raw material blocked polyisocyanate that has not reacted with the anionic compound (b), and an anionic compound that has not reacted with the raw material blocked polyisocyanate. Furthermore, unless otherwise specified, the various physical properties or characteristics of the blocked polyisocyanate composition of the present embodiment described below are characteristics that indicate a state in which the blocked polyisocyanate obtained by reacting the raw material blocked polyisocyanate with the anionic compound (hereinafter also referred to as a "modified blocked polyisocyanate") is included, the unreacted blocked raw material polyisocyanate, and the unreacted anionic compound are included.

[0122] The blocked polyisocyanate composition of the present embodiment has the above-described structure, and as will be shown in the examples described later, it has good dispersibility when blended with an aqueous base, and when formed into a coating film, it provides a blocked polyisocyanate composition that is excellent in gloss, water resistance, acid resistance, weather resistance, self-repairing property, and adhesion.

[0123] Each of the constituent components of the blocked polyisocyanate composition of the present embodiment will be described in detail below.

[0124] The diisocyanate (a), the anionic compound (b), and the alcohol (c) of this embodiment are the same as the respective components in the polyisocyanate composition described above.

[0125] <Thermal dissociation blocking agent> In the blocked polyisocyanate contained in the blocked polyisocyanate composition of this embodiment, at least a portion of the isocyanate groups are blocked with a thermally dissociable blocking agent. The thermally dissociable blocking agent is a compound having one active hydrogen atom in the molecule and has the property of dissociating from the isocyanate groups upon heating. Examples of the thermally dissociable blocking agent include alcohol-based compounds, alkylphenol-based compounds, phenol-based compounds, active methylene-based compounds, mercaptan-based compounds, acid amide-based compounds, acid imide-based compounds, imidazole-based compounds, urea-based compounds, oxime-based compounds, amine-based compounds, imine-based compounds, and pyrazole-based compounds.

[0126] More specifically, the thermally dissociable blocking agent is the compound shown below. These blocking agents may be used alone or in combination of two or more. (1) Alcohol compounds: methanol, ethanol, 2-propanol, n-butanol, sec-butanol, 2-ethyl-1-hexanol, 2-methoxyethanol, 2-ethoxyethanol, and 2-butoxyethanol. (2) Alkylphenol compounds: mono- or di-alkylphenols having an alkyl group having 4 or more carbon atoms as a substituent, such as mono-alkylphenols like n-propylphenol, i-propylphenol, n-butylphenol, sec-butylphenol, t-butylphenol, n-hexylphenol, 2-ethylhexylphenol, n-octylphenol, and n-nonylphenol; and di-n-propylphenol, diisopropylphenol, isopropyl cresol, di-n-butylphenol, di-t-butylphenol, di-sec-butylphenol, di-n-octylphenol, di-2-ethylhexylphenol, and di-n-nonylphenol. (3) Phenolic compounds: phenol, cresol, ethylphenol, styrenated phenol, hydroxybenzoic acid ester. (4) Active methylene compounds: dimethyl malonate, diethyl malonate, methyl acetoacetate, ethyl acetoacetate, acetylacetone. (5) Mercaptan compounds: butyl mercaptan, dodecyl mercaptan. (6) Acid amide compounds: acetanilide, acetic acid amide, ε-caprolactam, δ-valerolactam, γ-butyrolactam. (7) Acid imide compounds: succinimide, maleimide. (8) Imidazole compounds: imidazole, 2-methylimidazole. (9) Urea compounds: urea, thiourea, ethyleneurea. (10) Oxime compounds: formaldoxime, acetaldoxime, acetoxime, methyl ethyl ketoxime, cyclohexanone oxime. (11) Amine compounds: diphenylamine, aniline, carbazole, di-n-propylamine, diisopropylamine, isopropylethylamine. (12) Imine compounds: ethyleneimine, polyethyleneimine. (13) Pyrazole compounds: pyrazole, 3-methylpyrazole, 3,5-dimethylpyrazole.

[0127] Among these, the thermally dissociable blocking agent preferably contains at least one selected from the group consisting of oxime compounds, pyrazole compounds, active methylene compounds, amine compounds, and acid amide compounds, and from the viewpoint of storage stability when used as a coating liquid containing an amphipathic solvent, a pyrazole compound or an oxime compound is more preferred.

[0128] (Method for producing blocked polyisocyanate composition) The blocked polyisocyanate composition is not particularly limited, but can be obtained, for example, by reacting the above-mentioned polyisocyanate composition with the above-mentioned thermally dissociable blocking agent.

[0129] The reaction of the isocyanate group of the polyisocyanate with the anionic group of the anionic compound or the hydroxyl group of the alcohol, and the reaction of the isocyanate group of the polyisocyanate with the thermally dissociable blocking agent can be carried out simultaneously, or one of the reactions can be carried out first, followed by the second reaction. Among these, it is preferred to first carry out the reaction of the isocyanate group with the hydrophilic group of the anionic compound and the hydroxyl group of the alcohol to obtain a polyisocyanate having structural units derived from the anionic compound and the alcohol, and then to carry out the reaction with the thermally dissociable blocking agent.

[0130] In the reaction step, for example, organic metal salts of tin, zinc, lead, etc.; tertiary amine compounds; alcoholates of alkali metals such as sodium, etc. may be used as catalysts. The reaction temperature in the reaction step is preferably −20° C. or higher and 150° C. or lower, and more preferably 30° C. or higher and 100° C. or lower. When the reaction temperature is equal to or higher than the lower limit, reactivity tends to be increased. Furthermore, when the reaction temperature is equal to or lower than the upper limit, side reactions tend to be suppressed.

[0131] It is preferable to completely react the hydrophilic compound with the polyisocyanate so that no unreacted hydrophilic compound remains. This tends to further suppress the deterioration of the water dispersion stability of the water-dispersible blocked polyisocyanate composition and further suppress the deterioration of curability when used as a coating composition.

[0132] <Other components> The polyisocyanate composition and the blocked polyisocyanate composition of the present embodiment may contain other components, including, but not limited to, a solvent, an antioxidant, a light stabilizer, a polymerization inhibitor, a surfactant, and an antioxidant peroxide.

[0133] The solvent may be an organic solvent generally used as a paint solvent, and may be a hydrophilic solvent or a hydrophobic solvent. These solvents may be used alone or in combination. Among them, hydrophilic solvents are preferred.

[0134] The hydrophilic solvent is not particularly limited, but examples thereof include ethers and esters of ether alcohols.

[0135] Examples of the ethers include diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, and dipropylene glycol dimethyl ether.

[0136] Examples of esters of ether alcohols include ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol diacetate, and dipropylene glycol monomethyl ether acetate. Among these, from the viewpoint of improving dispersibility and pot life, propylene glycol diacetate, propylene glycol monomethyl ether acetate, etc. are preferred as the organic solvent.

[0137] In the polyisocyanate composition and blocked polyisocyanate composition of the present embodiment, the content of the organic solvent is preferably 20% by mass or more, more preferably 30% by mass or more, and even more preferably 40% by mass or more, relative to the total mass of the polyisocyanate composition, from the viewpoint of improving dispersibility, water resistance, and acid resistance.

[0138] In the polyisocyanate composition and blocked polyisocyanate composition of the present embodiment, the total content of the antioxidant, light stabilizer, polymerization inhibitor, and surfactant is preferably from 0% to 10% by mass, more preferably from 0% to 5% by mass, and even more preferably from 0% to 2% by mass, relative to the total mass of the polyisocyanate composition of the present embodiment.

[0139] <Coating composition> The coating composition of the present embodiment contains the polyisocyanate composition or the blocked polyisocyanate composition described above. The coating composition preferably further contains a resin dispersed or emulsified in water.

[0140] The above-mentioned polyisocyanate composition or blocked polyisocyanate composition can be mixed with an organic solvent and, optionally, a resin to be used as an organic solvent-based coating composition; however, it is preferable to mix it with a resin dispersed or emulsified in water to be used as a coating composition.

[0141] The coating composition of the present embodiment contains the polyisocyanate composition or blocked polyisocyanate composition described above, and thus when formed into a coating film, the coating composition has excellent gloss, water resistance, acid resistance, weather resistance, self-repairing property, and adhesion.

[0142] Next, each of the components contained in the coating composition of the present embodiment will be described in detail below.

[0143] (resin) In the coating composition, the resin used as the main component may be any resin that can be dispersed or emulsified in water, but an active hydrogen compound (a polyvalent active hydrogen compound) is preferred.

[0144] An active hydrogen compound is a compound with two or more active hydrogen atoms bonded to the molecule. Examples of active hydrogen compounds include polyols, polyamines, and polythiols, but polyols are the most commonly used.

[0145] Specific examples of such active hydrogen compounds include, but are not limited to, acrylic resins, polyester resins, polyether resins, epoxy resins, fluororesins, polyurethane resins, polyvinylidene chloride copolymers, polyvinyl chloride copolymers, vinyl acetate copolymers, acrylonitrile butadiene copolymers, polybutadiene copolymers, and styrene butadiene copolymers.

[0146] Among these, acrylic resins or polyester resins are preferred as the active hydrogen compound. For example, the hydroxyl value of the polyol is preferably 50 mgKOH / g or more and 250 mgKOH / g or less as the hydroxyl value in the resin component from the viewpoint of water resistance.

[0147] In the coating composition of the present embodiment, these resins may be used in combination with other resins such as melamine-based curing agents, urethane dispersions, and urethane acrylic emulsions, if necessary.

[0148] It is also preferable that these resins be emulsified, dispersed or dissolved in water, and for this purpose, the carboxyl groups, sulfonic groups, etc. contained in the resins can be neutralized.

[0149] The neutralizing agent for neutralizing the carboxy group, sulfone group, etc. is not particularly limited, but examples thereof include ammonia, water-soluble amino compounds, etc.

[0150] Examples of water-soluble amino compounds include monoethanolamine, ethylamine, dimethylamine, diethylamine, triethylamine, propylamine, dipropylamine, isopropylamine, diisopropylamine, triethanolamine, butylamine, dibutylamine, 2-ethylhexylamine, ethylenediamine, propylenediamine, methylethanolamine, dimethylethanolamine, diethylethanolamine, morpholine, etc. These may be used alone or in combination of two or more.

[0151] Among these, the neutralizing agent is preferably a tertiary amine, and more preferably triethylamine or dimethylethanolamine.

[0152] (Other ingredients) In addition to the polyisocyanate composition, blocked polyisocyanate composition, and resins described above, the coating composition of this embodiment may further contain additives commonly added to paints. Examples of such additives include extender pigments, silane coupling agents, titanium coupling agents, organic phosphates, organic phosphites, thickeners, leveling agents, thixotropic agents, antifoaming agents, freeze stabilizers, matting agents, crosslinking reaction catalysts (catalysts for curing acceleration), antiskinning agents, dispersants, wetting agents, fillers, plasticizers, lubricants, reducing agents, preservatives, antifungal agents, deodorizers, anti-yellowing agents, UV absorbers, antistatic agents or charge control agents, antisettling agents, surfactants, antioxidants, light stabilizers, and polymerization inhibitors. These additives may be contained alone or in combination of two or more.

[0153] (Method of producing coating composition) The coating composition of the present embodiment can be obtained by mixing the polyisocyanate composition, blocked polyisocyanate composition, and resins, and, if necessary, other components, using a known method.

[0154] For example, in the case of a water-based coating composition, the additives exemplified above under "other components" are added to a resin or its aqueous dispersion or solution as needed. Then, the polyisocyanate composition or its aqueous dispersion is added as a curing agent, and water or a solvent is further added as needed to adjust the viscosity. Then, the mixture is forcedly stirred with a stirring device to obtain a water-based coating composition.

[0155] When producing a solvent-based coating composition, first, the additives exemplified above under "other components" are added to the resin or its solvent dilution as needed. Next, the polyisocyanate composition is added as a curing agent, and if needed, a solvent is further added to adjust the viscosity. Next, the mixture is stirred by hand or with a stirring device such as a mixer to obtain a solvent-based coating composition.

[0156] <Coating substrate> The coated substrate of this embodiment is a substrate coated with the above-mentioned coating composition. The coated substrate of this embodiment preferably has a coating layer containing the above-mentioned coating composition.

[0157] The coated substrate of the present embodiment has a coating film formed by curing the above-described coating composition, and therefore has excellent appearance and water resistance.

[0158] The coated substrate of the present embodiment can be obtained by applying the above-described coating composition to a substrate using a known method such as roll coating, curtain flow coating, spray coating, bell coating, or electrostatic coating, and then drying or baking the composition at room temperature to allow it to harden.

[0159] The coating substrate of this embodiment may comprise a desired substrate and, optionally, a conventional primer prior to coating.

[0160] The substrates include metal, wood, glass, stone, ceramic materials, concrete, calcium silicate boards and gypsum boards, rigid and flexible plastics, textiles, leather products, paper, and the like.

[0161] The coated substrate of this embodiment is made of the above-mentioned coating composition, and the coating film provided on the coated substrate has excellent gloss, water resistance, acid resistance, weather resistance, self-repairing property, and adhesion.

[0162] (Usage) The polyisocyanate composition, blocked polyisocyanate composition, and coating composition of the present embodiment can be used in particular for architectural paints, automotive paints, automotive repair paints, construction and agricultural machinery paints, plastic paints, pressure-sensitive adhesives, adhesives, building materials, household water-based paints, and other coating agents, sealants, inks, casting materials, elastomers, foams, plastic raw materials, and fiber treatment agents. [Example]

[0163] The present invention will be explained in more detail below by way of examples and comparative examples, but the present invention is not limited to the following examples as long as it does not depart from the gist of the invention.

[0164] In the examples and comparative examples, the physical properties and evaluations of the polyisocyanate compositions were measured as follows. Unless otherwise specified, "parts" and "%" mean "parts by mass" and "% by mass".

[0165] <Measurement method> [Physical property 1: Viscosity] The viscosity was measured at 25°C using an E-type viscometer (manufactured by Tokimec Co., Ltd.). A standard rotor (1°34' x R24) was used. The rotation speeds were as follows:

[0166] (Rotation speed) 100 rpm (less than 128 mPa·s) 50 rpm (128 mPa·s or more but less than 256 mPa·s) 20 rpm (256 mPa·s or more but less than 640 mPa·s) 10 rpm (640 mPa·s or more but less than 1280 mPa·s) 5 rpm (1280 mPa·s or more but less than 2560 mPa·s) 2.5 rpm (2560 mPa·s or more but less than 5120 mPa·s)

[0167] [Property 2: Isocyanate group content (NCO%)] Using the polyisocyanate compositions obtained in the Examples and Comparative Examples as samples, the isocyanate group content was measured according to the method described in JIS K7301-1995 (Test method for tolylene diisocyanate prepolymers for thermosetting urethane elastomers). A more specific method for measuring the isocyanate group content (NCO%) is described below.

[0168] (1) 1 g (Wg) of sample was placed in a 200 mL Erlenmeyer flask, and 20 mL of toluene was added to the flask to dissolve the sample. (2) Then, 20 mL of a 2.0 N di-n-butylamine-toluene solution was added to the flask and allowed to stand for 15 minutes. (3) 70 mL of 2-propanol was added to the flask and dissolved to obtain a solution. (4) The solution obtained in (3) above was titrated with 1 mol / L hydrochloric acid to determine the sample titer (V1mL). (5) Even when no sample was added, measurements were carried out in the same manner as in (1) to (3) above, and the blank titer (V0 mL) was determined. The isocyanate group content (NCO%) was calculated from the sample titer and blank titer determined above using the following formula (A).

[0169] Isocyanate group content (mass%) = (V0-V1)×42 / [W(1g)×1000]×100 (A)

[0170] [Property 3: Non-volatile content] When the polyisocyanate compositions obtained in the Examples and Comparative Examples were used as samples and diluted with a solvent, the nonvolatile content was calculated using the method shown below. First, the mass of an aluminum cup was precisely weighed (W0 g), and approximately 1 g of sample was placed inside. The mass of the cup before heat drying (W1 g) was then precisely weighed. The cup containing the sample was then heated in a dryer at 105°C for 3 hours. After heating, the cup was cooled to room temperature, and the mass of the cup was then precisely weighed again (W2 g). Next, the nonvolatile content was calculated using the mass % of the dry residue in the sample as the nonvolatile content using the following formula (B). Note that when no solvent dilution was used, the nonvolatile content was treated as being essentially 100%. Nonvolatile content (mass%) = (W2-W0) / (W1-W0) x 100 (B)

[0171] [Physical Property 4: Molar fraction of allophanate groups relative to the total amount of isocyanurate groups and allophanate groups (hereinafter referred to as allophanate group mole fraction)] The polyisocyanate compositions obtained in the examples and comparative examples were subjected to a filtration test using Biospin Avance 600 (trade name) manufactured by Bruker. 13 C-NMR measurements were carried out under the following specific measurement conditions:

[0172] (Measurement conditions) 13 C-NMR device: AVANCE600 (manufactured by Bruker) Cryoprobe (Bruker) CryoProbe® CPDUL 600S3-C / HD-05Z Resonance frequency: 150MHz Concentration: 60wt / vol% Shift standard: CDCl3 (77 ppm) Accumulation count: 10,000 times Pulse program: zgpg30 (proton fully decoupled, waiting time 2 seconds)

[0173] The integral value of the following signals was divided by the number of carbon atoms being measured to determine the mole fraction of each group relative to the total of isocyanurate groups and allophanate groups. Isocyanurate group: (integrated value around 148.6 ppm) ÷ 3 Allophanate group: (integrated value around 154 ppm) ÷ 1

[0174] [Physical Property 5: Number average molecular weight of alcohol] Using alcohol as a sample, the number average molecular weight of the alcohol was calculated using the following formula (3): The hydroxyl value of the alcohol was calculated using the following (Physical Property 9). Number average molecular weight = 2 / (hydroxyl number of alcohol × 10-3 / 56.11) (3)

[0175] [Physical Property 6: Qualitative Analysis of Polyisocyanate Compositions Bonded to Anionic Compounds and Their Polyol Components] Using a polyisocyanate composition as a sample, the polyisocyanate composition bonded to an anionic compound and its polyol component were qualitatively analyzed using a WATERS "UPLC" with LC-MS and UV-MS, with retention times of 3.8 min and 4.5 min, respectively. LC device: manufactured by WATERS, UPLC (product name) Column: WATERS ACQUITY UPLC BEH T3 1.7 μm C18, inner diameter 2.1 mm x 50 mm Flow rate: 0.3mL / min Mobile phase: A = water (0.1% HCOOH), B = acetonitrile (0.1% HCOOH) Gradient conditions: The initial mobile phase composition was A / B=98 / 2, and after sample injection, the ratio of B was increased linearly until it reached A / B=0 / 100 after 10 minutes. MS device: WATERS Synapt G2 Ionization: ESI+, ESI-

[0176] [Physical Properties 7] (mass fraction of anionic compounds) The content of the anionic compound contained in the polyisocyanate compositions obtained in the Examples and Comparative Examples was determined by detecting the sulfur and phosphorus atom contents by ion chromatography (IC) using the following apparatus and conditions, and calculating the mass fraction of the anionic compound.

[0177] IC device: Thermo Fisher Scientific, ICS-1500 (product name) Column: AS12A Mobile phase: 2.7mmol / L Na2CO3, 0.3mmol / L NaHCO3 Flow rate: 1.5mL / min Sample injection volume: 1 mL Suppressor: AERS-500 Detector: Electrical conductivity detector Pretreatment method: The sample was burned in a furnace and the combustion gas was absorbed in an absorption liquid.

[0178] [Physical Properties 8] (Qualitative analysis of amine compounds) The amine compounds contained in the polyisocyanate compositions obtained in the Examples and Comparative Examples were qualitatively characterized by mass spectrometry after separation by pyrolysis gas chromatography using the following equipment and conditions.

[0179] Pyrolysis equipment: FRONTIER LAB Py3030D Heating temperature: 600℃ Heating atmosphere: He GC / MS equipment: Agilent6890 / MSD5975C Column: DB-1 Column temperature: 40°C (5 min) → 20°C / min temperature increase → 300°C (hold for 11 min) Column flow rate: 1.0 mL / min Inlet temperature: 320℃ Injection method: Split method (split ratio: 1 / 50) Ion source temperature: 230℃ Interface temperature: 300℃ Ionization method: electron ionization method Sample amount: 0.3 mg

[0180] <Evaluation method> [Preparation Example 1: Production of pigment dispersion] A SUS cup was charged with 249 parts by weight of deionized water, 700 parts by weight of pigment (R-902, manufactured by DuPont), 49 parts by weight of dispersant (BYK-190, manufactured by BYK Chemie), 2.0 parts by weight of antifoaming agent (Tego Airex 902W, manufactured by Evonik Industries), and 400 parts by weight each of 1 mm and 0.5 mm beads. The mixture was stirred in a disperser at 3,000 rpm for 60 minutes. The mixture was then stirred in a sand mill until the particle size reached 10 μm, yielding a pigment dispersion.

[0181] [Preparation Example 2: Production of Resin Dispersion] To a stainless steel cup were added 650 parts by mass of an aqueous acrylic polyol (Bayhydrol A2470, manufactured by Covestro), 340 parts by mass of the pigment dispersion prepared in [Production Example 3], 2.0 parts by mass of an antifoaming agent (BYK-024, manufactured by BYK Chemie), 2.0 parts by mass of a wetting agent (BYK-346, manufactured by BYK Chemie), and 3.0 parts by mass of a rheology agent (B299, manufactured by Elmentis). The mixture was stirred with a disper at 2000 rpm for 30 minutes to obtain a resin dispersion.

[0182] Preparation Example 3: Production of Coating Composition Propylene glycol methyl ether acetate (PMA) was added to the polyisocyanate compositions obtained in the Examples and Comparative Examples to prepare solutions of polyisocyanate compositions with a nonvolatile content of 70%. Next, 100 g of the resin dispersion prepared in Preparation Example 2 above was weighed out, and each polyisocyanate solution was added thereto in such a ratio that the ratio (NCO / OH) of the molar amount of isocyanate groups in the polyisocyanate compositions obtained in the Examples and Comparative Examples to the molar amount of hydroxyl groups in this resin dispersion was 1.5, followed by stirring at 600 rpm for 5 minutes. Further, deionized water was added to adjust the viscosity to 25 seconds in a Ford cup (No. 4) at 25°C, and the mixture was stirred at 600 rpm for 5 minutes using a propeller blade to obtain each coating composition.

[0183] The following evaluations were carried out using each of the prepared coating compositions.

[0184] [Rating 1: Dispersibility] Using each coating composition produced in Preparation Example 3 as a sample, dispersibility was evaluated using the following methods (1) to (4). (1) The mass of the 100 mL flask and the Yoshino paper was measured. (2) 20.0 g of the coating composition was placed in a 100 mL flask and filtered through the Yoshino paper weighed in (1). (3) The mass (g) of the filtration residue remaining on the Yoshino paper and the residue remaining in the 100 mL flask was calculated. (4) Dispersibility was evaluated according to the following evaluation criteria: The smaller the mass (g) of the residue, the better the dispersibility was evaluated, and the larger the mass (g) was, the worse the dispersibility was evaluated.

[0185] (Evaluation criteria) A: Less than 0.2g B: 0.2g or more but less than 0.5g C: 0.5g or more and less than 1.0g D: 1.0g or more, granular undissolved matter remained,

[0186] [Evaluation 2: Coating gloss] Each coating composition prepared in Preparation Example 3 was applied to a steel plate pretreated with a sandblaster on a horizontal table using an air spray (spray pressure: 0.3 MPa, spray nozzle: 1.8 mm) to a dry film thickness of 50±5 μm. In the examples and comparative examples other than Example 21, the coating film was obtained by drying for 7 days in an atmosphere of 23°C and 50% RH. In Example 21, the coating film was obtained by baking at 120°C for 1 hour and then drying.

[0187] The 60-degree gloss value was then measured in accordance with GB-T6753.1-2007 using a gloss meter (BYK micro-TRI-gloss). The gloss of the coating film was evaluated according to the following evaluation criteria. The higher the 60-degree gloss value, the better the gloss of the coating film, and the lower the value, the worse the gloss. Evaluated.

[0188] (Evaluation criteria) A: 60 degree gloss value is 90% or more B: 60 degree gloss value is 80% or more but less than 90% C: 60 degree gloss value is 70% or more but less than 80% D: 60 degree gloss value is less than 70%

[0189] [Rating 3: Initial water resistance] Using the same method as in "Evaluation 2" above, each polyisocyanate composition was cured to obtain a coating film. Next, in accordance with GB-T1773-1993, a steel plate (hereinafter sometimes referred to as "coated plate") with a coating film was immersed in water at 23°C for 24 hours, and the state of the coating film was observed after removing the water remaining on the surface. The water resistance of the coating film was evaluated according to the following evaluation criteria. The longer the time until blisters and blistering occurred, the better the water resistance of the coating film was evaluated, and the shorter the time, the worse the evaluation. In the following evaluation criteria, "blistering" refers to bubbles or blisters that appear on the surface of the coating film.

[0190] (Evaluation criteria) A: No blisters for 4 days or more B: No blistering within 2 days or more but less than 4 days C: Swelling and blistering occur within 1 to 2 days D: Swelling and blistering in less than a day

[0191] [Rating 4: Acid resistance] Using the same method as in "Evaluation 2" above, each polyisocyanate composition was cured to obtain a coating film. Next, in accordance with GB-T9274-1988, a steel plate with a coating film (hereinafter sometimes referred to as "coated plate") was immersed in a diluted acid solution at 23°C for 24 hours, and the state of the coating film was observed after removing the liquid remaining on the surface. The acid resistance of the coating film was evaluated according to the following evaluation criteria. The longer the time until blistering occurred, the better the water resistance of the coating film was evaluated, and the shorter the time, the worse the evaluation.

[0192] (Evaluation criteria) A: Swelling occurs after 4 days or more B: Swelling occurs in 3 days or more but less than 4 days C: Swelling occurs in 2 days or more but less than 3 days D: Swelling occurs in less than 2 days

[0193] [Rating 5: Self-repairing] Using the same method as in "Evaluation 2" above, each polyisocyanate composition was cured to obtain a coating film. Then, at 25°C, each coated plate was reciprocated 10 times with steel wool #0000 under a 500g load, and after 4 hours, the self-repairing property of the coating film was visually observed and evaluated. The self-repairing property of the coating film was evaluated according to the following evaluation criteria. The fewer scratches, the better the self-repairing property of the coating film, and the more scratches, the worse the evaluation.

[0194] (Evaluation criteria) A: No scratches at all B: 1 to 3 scratches C: 4 to 10 scratches D: More than 10 scratches

[0195] [Evaluation 6: Adhesion] Using the same method as in "Evaluation 2" above, each polyisocyanate composition was cured to obtain a coating film. Next, in accordance with GB-T9286-2021, 100 1mm-wide squares were created using a cutter knife so that they reached the base of the coated board, and cellophane tape was then applied to the squares. The cellophane tape was then quickly peeled off, and adhesion was evaluated according to the following evaluation criteria. The more squares where the coating film did not separate, the better the adhesion, and the fewer the squares, the worse the adhesion.

[0196] (Evaluation criteria) A: The number of squares where the coating does not peel off is 100 B: The number of squares where the coating does not peel off is 90 to 99 C: The number of squares where the coating film does not peel off is 70 to 89. D: The number of squares where the coating film does not peel off is 70 or less

[0197] [Rating 7: Weather resistance] Each polyisocyanate composition was cured to obtain a coating film using the same method as in "Evaluation 2" above. Tests were then carried out under the following measurement conditions in accordance with GB-T1865-2009.

[0198] (Measurement conditions) Equipment: QUV (product name) (Q-Lab) Irradiance: 0.68 (W / m 2 / nm) Black panel temperature (dry): 60°C Black panel temperature (when raining): 40°C Rainfall cycle: 40℃ x 4 hours (without irradiation), 60℃ x 4 hours (with irradiation) Measurement time: 50 days

[0199] After the test, the condition of the coating film on the coated plate (60° gloss retention) was checked and evaluated according to the following evaluation criteria. The higher the 60° gloss retention, the better the weather resistance, and the lower the 60° gloss retention, the worse the weather resistance.

[0200] (Evaluation criteria) A: 60° gloss retention: 90% or more B: 60° gloss retention: 85% or more but less than 90% C: 60° gloss retention: 75% or more and less than 85% D: 60° gloss retention: less than 75%

[0201] <Synthesis of amine sulfonates> [Synthesis Example 1] (Synthesis of HES / TPA) To 20 parts by mass of a 70% by mass aqueous solution of 2-hydroxyethanesulfonic acid (hereinafter sometimes abbreviated as "HES"), 10 parts by mass of 1-propanol was added and stirred to obtain a solution. Furthermore, tripropylamine (hereinafter sometimes abbreviated as "TPA") was weighed out in a proportion such that the molar equivalent ratio to HES was 1, and the solution was diluted with the same part by mass of 1-propanol and added dropwise to the stirred solution. One hour after the start of the dropwise addition, stirring was stopped, and the mixture was dehydrated and desolvated in an evaporator to obtain 2-hydroxyethanesulfonic acid tripropylamine salt (hereinafter sometimes abbreviated as "HES / TPA") with a solids content of 99.8% by mass.

[0202] [Synthesis Example 2] (Synthesis of HES / TBA) To 20 parts by mass of a 70% by mass aqueous solution of 2-hydroxyethanesulfonic acid (hereinafter sometimes abbreviated as "HES"), 10 parts by mass of 1-propanol was added and stirred to obtain a solution. Furthermore, tributylamine (hereinafter sometimes abbreviated as "TBA") was weighed out in a proportion such that the molar equivalent ratio to HES was 1, and the solution was diluted with the same part by mass of 1-propanol and added dropwise to the stirred solution. One hour after the start of the dropwise addition, stirring was stopped, and the mixture was dehydrated and desolvated in an evaporator to obtain 2-hydroxyethanesulfonic acid tributylamine salt (hereinafter sometimes abbreviated as "HES / TBA") with a solids content of 99.8% by mass.

[0203] [Synthesis Example 3] (Production of Polyisocyanate Composition P1) A 1L four-neck flask equipped with a stirrer, thermometer, reflux condenser, nitrogen inlet, and dropping funnel was conditioned with nitrogen and charged with 1,000 parts by weight of HDI. The temperature inside the reactor was maintained at 70°C for 1 hour while stirring. Subsequently, 1.0 parts by weight of a solution of tetramethylammonium caprate (a catalyst for isocyanuration) diluted to 5% by weight with isobutanol (hereinafter also referred to as "I-BuOH") was added, and the reaction was continued at 70°C. When the yield reached 25% by weight, phosphoric acid was added to terminate the reaction. The reaction solution was heated at 100°C for 1 hour, cooled, filtered, and then unreacted HDI was removed using a thin-film evaporator to obtain polyisocyanate composition P1. The viscosity of the resulting polyisocyanate composition P1 at 25°C was 1,300 mPa·s, and the NCO content was 23.0% by weight.

[0204] [Synthesis Example 4] (Production of Polyisocyanate Composition P2) A nitrogen atmosphere was placed inside the same reactor as in Synthesis Example 3, and 1,000 parts by mass of HDI and 3.1 parts by mass of 2-ethylhexanol (hereinafter also referred to as "2EH") were charged. The temperature inside the reactor was maintained at 80°C for 2 hours with stirring. Tetramethylammonium caprate, an isocyanurate reaction catalyst, was then added, and when the yield reached 40% by mass, phosphoric acid was added to terminate the reaction. The reaction solution was filtered, and unreacted HDI was removed using a thin-film evaporator to obtain polyisocyanate composition P2. The viscosity of the resulting polyisocyanate composition P2 at 25°C was 2,600 mPa·s, and the NCO content was 21.7% by mass.

[0205] [Synthesis Example 5] (Production of Polyisocyanate Composition P3) A nitrogen atmosphere was placed inside the same reactor as in Synthesis Example 3, and 1,000 parts by mass of HDI and 30 parts by mass of 2EH were added. The temperature inside the reactor was maintained at 90°C with stirring for 1 hour. Tetramethylammonium caprate, an allophanation and isocyanuration reaction catalyst, was then added, and when the yield reached 19% by mass, phosphoric acid was added to terminate the reaction. The reaction solution was filtered, and unreacted HDI was removed using a thin-film evaporator to obtain Polyisocyanate Composition P3. The viscosity of the resulting Polyisocyanate Composition P3 at 25°C was 480 mPa·s, and the NCO content was 23.3% by mass.

[0206] [Synthesis Example 6] (Production of Polyisocyanate Composition P4) A nitrogen atmosphere was placed inside the same reactor as in Synthesis Example 3, and 1,000 parts by weight of HDI was charged. The reactor temperature was maintained at 70°C for 1 hour with stirring. Subsequently, 1.0 part by weight of a solution of tetramethylammonium caprate (an isocyanurate reaction catalyst) diluted to 5% by weight with I-BuOH was added, and the reaction was carried out at 70°C. When the yield reached 42% by weight, phosphoric acid was added to terminate the reaction. The reaction solution was heated at 100°C for 1 hour, cooled, filtered, and then unreacted HDI was removed using a thin-film evaporator to obtain Polyisocyanate Composition P4. The viscosity of the resulting Polyisocyanate Composition P4 at 25°C was 2,700 mPa·s, and the NCO content was 21.7% by weight.

[0207] [Synthesis Example 7] (Production of Polyisocyanate Composition P5) A nitrogen atmosphere was created inside the same apparatus as in Synthesis Example 3, and 920 parts by mass of Polyisocyanate Composition P2 obtained in Synthesis Example 4 and 80 parts by mass of HES / TPA obtained in Synthesis Example 1 were added, followed by stirring at 105°C for 5 hours to carry out a reaction, yielding Polyisocyanate Composition P5. The viscosity of the obtained Polyisocyanate Composition P5 at 25°C was 13,000 mPa s, and the NCO content was 18.7% by mass.

[0208] [Synthesis Example 8] (Production of Polyisocyanate Composition P6) A nitrogen atmosphere was created inside an apparatus similar to that used in Synthesis Example 3, and 916 parts by mass of Polyisocyanate Composition P2 obtained in Synthesis Example 4 and 4 parts by mass of 1,3-butanediol (hereinafter also referred to as "BDO") were charged. The temperature inside the reactor was maintained at 90°C for 1 hour with stirring. 80 parts by mass of HES / TPA obtained in Synthesis Example 1 was then added, and the reaction was carried out with stirring at 105°C for 5 hours to obtain Polyisocyanate Composition P6. The viscosity of the obtained Polyisocyanate Composition P6 at 25°C was 15,000 mPa s, and the NCO content was 18.3% by mass.

[0209] [Synthesis Example 9] (Production of Polyisocyanate Composition P7) A nitrogen atmosphere was created inside an apparatus similar to that used in Synthesis Example 3, and 900 parts by mass of Polyisocyanate Composition P3 obtained in Synthesis Example 5 and 20 parts by mass of BDO were charged. The temperature inside the reactor was maintained at 90°C for 1 hour with stirring. 80 parts by mass of HES / TPA obtained in Synthesis Example 1 was then added, and the reaction was carried out with stirring at 105°C for 5 hours to obtain Polyisocyanate Composition P7. The viscosity of the resulting Polyisocyanate Composition P7 at 25°C was 5,000 mPa s, and the NCO content was 17.7% by mass.

[0210] [Example 1] (Production of polyisocyanate composition PA1) A 2L, four-neck flask equipped with a stirrer, thermometer, reflux condenser, nitrogen inlet, and dropping funnel was purged with nitrogen and charged with 1,000 parts by weight of HDI and 30.0 parts by weight of 2EH. The temperature inside the reactor was maintained at 90°C for 1 hour while stirring. Tetramethylammonium caprate, an isocyanurate-allophanate reaction catalyst, was then added, and the reaction was continued at 80°C. When the yield reached 48% by weight, phosphoric acid was added to terminate the reaction. The reaction solution was heated at 100°C for 1 hour, cooled, filtered, and then unreacted HDI was removed using a thin-film evaporator to obtain polyisocyanate composition PA1'.

[0211] To the resulting 482.5 g of polyisocyanate composition PA1', 17.5 g of HES / TPA obtained in Synthesis Example 1 was added, and the mixture was stirred at 105° C. for 5 hours to carry out a reaction, thereby obtaining polyisocyanate composition PA1. The physical properties and evaluation results of the obtained polyisocyanate composition PA1 are shown in Table 1 below.

[0212] [Example 2] (Production of polyisocyanate composition PA2) Polyisocyanate composition PA2' was obtained in the same manner as in Example 1, except that 30.0 parts by mass of 2EH was replaced with 30.0 parts by mass of PTG-250 (manufactured by Hodogaya Chemical Co., Ltd., polytetramethylene glycol (average number of hydroxyl groups per molecule: 2, number average molecular weight: 250)) and the reaction was stopped when the yield reached 50% by mass.

[0213] To the resulting 481 g of polyisocyanate composition PA2', 19.0 g of HES / TPA obtained in Synthesis Example 1 was added, and the mixture was stirred at 105° C. for 5 hours to carry out a reaction, thereby obtaining polyisocyanate composition PA2. The physical properties and evaluation results of the obtained polyisocyanate composition PA2 are shown in Table 1 below.

[0214] [Example 3] (Production of polyisocyanate composition PA3) Polyisocyanate composition PA3' was obtained in the same manner as in Example 1, except that 30.0 parts by mass of 2EH was replaced with 30.0 parts by mass of PTG-1000 (manufactured by Hodogaya Chemical Co., Ltd., polytetramethylene glycol (average number of hydroxyl groups per molecule: 2, number average molecular weight: 1000)) and the reaction was stopped when the yield reached 30% by mass.

[0215] To the resulting 481 g of polyisocyanate composition PA3', 19.0 g of HES / TPA obtained in Synthesis Example 1 was added, and the mixture was stirred at 105° C. for 5 hours to carry out a reaction, thereby obtaining polyisocyanate composition PA3. The physical properties and evaluation results of the obtained polyisocyanate composition PA3 are shown in Table 1 below.

[0216] [Example 4] (Production of polyisocyanate composition PA4) A polyisocyanate composition PA4' was obtained in the same manner as in Example 1, except that 100.0 parts by mass of Excenol 840 (AGC Corporation, polypropylene glycol (EO-terminated type) (average number of hydroxyl groups per molecule: 3, number average molecular weight: 6500)) was added instead of 30.0 parts by mass of 2EH, and the reaction was stopped when the yield reached 22% by mass.

[0217] To the resulting 480 g of polyisocyanate composition PA4', 20.0 g of HES / TPA obtained in Synthesis Example 1 was added, and the mixture was stirred at 105° C. for 5 hours to carry out a reaction, thereby obtaining polyisocyanate composition PA4. The physical properties and evaluation results of the obtained polyisocyanate composition PA4 are shown in Table 1 below.

[0218] [Example 5] (Production of polyisocyanate composition PA5) A polyisocyanate composition PA5' was obtained in the same manner as in Example 1, except that 100.0 parts by mass of Excenol 510 (manufactured by AGC Inc., polypropylene glycol (EO-terminated type) (average number of hydroxyl groups per molecule: 2, number average molecular weight: 4500)) was added instead of 30.0 parts by mass of 2EH, and the reaction was stopped when the yield reached 28% by mass.

[0219] To the resulting 480 g of polyisocyanate composition PA5', 20.0 g of HES / TPA obtained in Synthesis Example 1 was added, and the mixture was stirred at 105° C. for 5 hours to carry out a reaction, thereby obtaining polyisocyanate composition PA5. The physical properties and evaluation results of the obtained polyisocyanate composition PA5 are shown in Table 1 below.

[0220] [Example 6] (Production of polyisocyanate composition PA6) A nitrogen atmosphere was created inside the same reactor as in Example 1, and 1,000 parts by mass of HDI and 140 parts by mass of PLACCEL 305 (manufactured by Daicel Corporation, polycaprolactone polyol (average number of hydroxyl groups per molecule: 3, number average molecular weight: 550) (hereinafter also referred to as "PCL-305")) were charged, and the temperature inside the reactor was maintained at 100°C for 1 hour with stirring. Thereafter, unreacted HDI was removed from the reaction liquid using a thin-film evaporator, and polyisocyanate composition PA6' was obtained.

[0221] To the resulting 480 g of polyisocyanate composition PA6', 480 g of polyisocyanate composition P2 obtained in Synthesis Example 4 and 40.0 g of HES / TPA obtained in Synthesis Example 1 were added, and the mixture was stirred at 105°C for 5 hours to carry out a reaction, thereby obtaining polyisocyanate composition PA6. The physical properties and evaluation results of the obtained polyisocyanate composition PA6 are shown in Table 1 below.

[0222] [Example 7] (Production of polyisocyanate composition PA7) Instead of 140 parts by mass of PCL-305, 250 parts by mass of PLACCEL 308 (manufactured by Daicel Corporation, polycaprolactone polyol (average number of hydroxyl groups per molecule: 3, number average molecular weight: 850) (hereinafter also referred to as "PCL-308")) was charged, and the temperature inside the reactor was maintained at 100°C for 1 hour with stirring. Polyisocyanate composition PA7' was obtained.

[0223] To the resulting 480 g of polyisocyanate composition PA7', 480 g of polyisocyanate composition P2 obtained in Synthesis Example 4 and 40.0 g of HES / TPA obtained in Synthesis Example 1 were added, and the mixture was stirred at 105°C for 5 hours to carry out a reaction, thereby obtaining polyisocyanate composition PA7. The physical properties and evaluation results of the obtained polyisocyanate composition PA7 are shown in Table 1 below.

[0224] [Example 8] (Production of polyisocyanate composition PA8) Instead of 140 parts by mass of PCL-305, 80 parts by mass of PCL-305 and 150 parts by mass of PTG-1000 (manufactured by Hodogaya Chemical Co., Ltd., polytetramethylene glycol (average number of hydroxyl groups per molecule: 2, number average molecular weight: 1000)) were charged, and the temperature inside the reactor was maintained at 90°C for 1 hour while stirring. Thereafter, unreacted HDI was removed from the reaction liquid using a thin-film evaporator, and polyisocyanate composition PA8' was obtained.

[0225] To the resulting 478 g of polyisocyanate composition PA8', 480 g of polyisocyanate composition P1 obtained in Synthesis Example 3 and 42.0 g of HES / TBA obtained in Synthesis Example 2 were added, and the mixture was stirred at 105°C for 5 hours to carry out a reaction, thereby obtaining polyisocyanate composition PA8. The physical properties and evaluation results of the obtained polyisocyanate composition PA8 are shown in Table 2 below.

[0226] [Example 9] (Production of polyisocyanate composition PA9) A polyisocyanate composition PA9' was obtained in the same manner as in Example 1, except that the reaction was stopped when the yield reached 48% by mass.

[0227] To the resulting 480 g of polyisocyanate composition PA9', 20 g of HES / TPA obtained in Synthesis Example 1 was added, and the mixture was stirred at 105° C. for 5 hours to carry out a reaction, thereby obtaining polyisocyanate composition PA9. The physical properties and evaluation results of the obtained polyisocyanate composition PA9 are shown in Table 2 below.

[0228] [Example 10] (Production of polyisocyanate composition PA10) A polyisocyanate composition PA10' was obtained in the same manner as in Example 1, except that 150.0 parts by mass of 2EH was charged instead of 30.0 parts by mass of 2EH, and the reaction was stopped when the yield reached 54% by mass.

[0229] To the resulting 480 g of polyisocyanate composition PA10', 20 g of HES / TPA obtained in Synthesis Example 1 was added, and the mixture was stirred at 105° C. for 5 hours to carry out a reaction, thereby obtaining polyisocyanate composition PA10. The physical properties and evaluation results of the obtained polyisocyanate composition PA10 are shown in Table 2 below.

[0230] [Example 11] (Production of polyisocyanate composition PA11) A polyisocyanate composition PA11' was obtained in the same manner as in Example 6, except that 250 parts by mass of PCL-308 was charged instead of 140 parts by mass of PCL-305.

[0231] To 500 g of the resulting polyisocyanate composition PA11', 500 g of the polyisocyanate composition P5 obtained in Synthesis Example 7 was added, and the mixture was stirred at 60° C. for 2 hours to obtain a polyisocyanate composition PA11. The physical properties and evaluation results of the obtained polyisocyanate composition PA11 are shown in Table 2 below.

[0232] [Example 12] (Production of polyisocyanate composition PA12) In the same manner as in Example 11, a polyisocyanate composition PA12' was obtained.

[0233] To 500 g of the resulting polyisocyanate composition PA12', 500 g of the polyisocyanate composition P6 obtained in Synthesis Example 8 was added, and the mixture was stirred at 60° C. for 2 hours to obtain a polyisocyanate composition PA12. The physical properties and evaluation results of the obtained polyisocyanate composition PA12 are shown in Table 2 below.

[0234] [Example 13] (Production of polyisocyanate composition PA13) In the same manner as in Example 11, a polyisocyanate composition PA13' was obtained.

[0235] To 500 g of the resulting polyisocyanate composition PA13', 500 g of the polyisocyanate composition P7 obtained in Synthesis Example 9 was added, and the mixture was stirred at 60° C. for 2 hours to obtain a polyisocyanate composition PA13. The physical properties and evaluation results of the obtained polyisocyanate composition PA13 are shown in Table 2 below.

[0236] [Example 14] (Production of polyisocyanate composition PA14) In the same manner as in Example 8, a polyisocyanate composition PA14' was obtained.

[0237] To 500 g of the resulting polyisocyanate composition PA14', 500 g of the polyisocyanate composition P7 obtained in Synthesis Example 9 was added, and the mixture was stirred at 60° C. for 2 hours to obtain a polyisocyanate composition PA14. The physical properties and evaluation results of the obtained polyisocyanate composition PA14 are shown in Table 2 below.

[0238] [Example 15] (Production of polyisocyanate composition PA15) Polyisocyanate composition PA15' was obtained in the same manner as in Example 1, except that 50.0 parts by mass of PTG-250 (manufactured by Hodogaya Chemical Co., Ltd., polytetramethylene glycol (average number of hydroxyl groups per molecule: 2, number average molecular weight: 250)) was added instead of 30.0 parts by mass of 2EH, and the reaction was stopped when the yield reached 42% by mass.

[0239] To 150 g of the resulting polyisocyanate composition PA15', 850 g of the polyisocyanate composition P7 obtained in Synthesis Example 9 was added, and the mixture was stirred at 60° C. for 2 hours to obtain a polyisocyanate composition PA15. The physical properties and evaluation results of the obtained polyisocyanate composition PA15 are shown in Table 3 below.

[0240] [Example 16] (Production of polyisocyanate composition PA16) Polyisocyanate composition PA16' was obtained in the same manner as in Example 1, except that 50.0 parts by mass of PTG-250 was added instead of 30.0 parts by mass of 2EH, and the reaction was stopped when the yield reached 42% by mass.

[0241] To the resulting 850 g of polyisocyanate composition PA16', 150 g of the polyisocyanate composition P7 obtained in Synthesis Example 9 was added, and the mixture was stirred at 60° C. for 2 hours to obtain polyisocyanate composition PA16. The physical properties and evaluation results of the obtained polyisocyanate composition PA16 are shown in Table 3 below.

[0242] [Example 17] (Production of polyisocyanate composition PA17) A polyisocyanate composition PA17 was obtained in the same manner as in Example 1, except that the amount of polyisocyanate composition PA1 added was changed to 495 g and the amount of HES / TPA added was changed to 5.0 g. The physical properties and evaluation results of the obtained polyisocyanate composition PA17 are shown in Table 3 below.

[0243] [Example 18] (Production of polyisocyanate composition PA18) A polyisocyanate composition PA18 was obtained in the same manner as in Example 1, except that the amount of polyisocyanate composition PA1 added was changed to 464 g and the amount of HES / TPA added was changed to 36 g. The physical properties and evaluation results of the obtained polyisocyanate composition PA18 are shown in Table 3 below.

[0244] [Example 19] (Production of polyisocyanate composition PA19) A polyisocyanate composition PA19 was obtained in the same manner as in Example 6, except that HDI was changed to PDI. The physical properties and evaluation results of the obtained polyisocyanate composition PA19 are shown in Table 3 below.

[0245] [Example 20] (Production of polyisocyanate composition PA20) A polyisocyanate composition PA20' was obtained in the same manner as in Example 6, except that 250 parts by mass of PCL-308 was charged instead of 140 parts by mass of PCL-305.

[0246] To the resulting 480 g of polyisocyanate composition PA20′, 480 g of polyisocyanate composition P2 obtained in Synthesis Example 4, 25 g of 3-cyclohexylaminopropanesulfonic acid (CAPS), and 15 g of N,N-dimethylcyclohexylamine (DMCHA) were added, and the mixture was stirred at 90°C for 5 hours to carry out a reaction, thereby obtaining polyisocyanate composition PA20. The physical properties and evaluation results of the obtained polyisocyanate composition PA20 are shown in Table 3 below.

[0247] [Example 21] (Production of Blocked Polyisocyanate Composition BL-PA1) In the same manner as in Example 7, a polyisocyanate composition BL-PA1' was obtained.

[0248] To 480 g of the resulting polyisocyanate composition BL-PA1', 480 g of the polyisocyanate composition P2 obtained in Synthesis Example 4 and 40.0 g of 2-hydroxyethanesulfonic acid tripropylamine salt (HES / TPA) obtained in Synthesis Example 1 were added, and the mixture was stirred at 105°C for 5 hours to carry out a reaction. Then, 215 g of 3,5-dimethylpyrazole was added, and a blocking reaction was carried out while controlling the temperature inside the reactor at 90°C to 100°C. Then, 306 g of dipropylene glycol monomethyl ether (DPM) was added, and the mixture was stirred at 60°C for 2 hours to obtain blocked polyisocyanate composition BL-PA1. The physical properties and evaluation results of the resulting blocked polyisocyanate composition BL-PA11 are shown in Table 3 below.

[0249] [Comparative Example 1] (Production and Evaluation of Polyisocyanate Composition PB1) A polyisocyanate composition PB1 was obtained in the same manner as in Example 6, except that HDI was changed to bis(isocyanatomethyl)cyclohexane (HXDI). The physical properties and evaluation results of the obtained polyisocyanate composition PB1 are shown in Table 4 below.

[0250] Comparative Example 2 (Production and Evaluation of Polyisocyanate Composition PB2) A nitrogen atmosphere was created inside an apparatus similar to that used in Example 1, and 960 parts by mass of polyisocyanate composition P6 obtained in Synthesis Example 6 and 40 parts by mass of HES / TPA obtained in Synthesis Example 1 were added, followed by stirring at 105°C for 5 hours to carry out a reaction, thereby producing polyisocyanate composition PB2. The physical properties and evaluation results of the obtained polyisocyanate composition PB2 are shown in Table 4 below.

[0251] Comparative Example 3 (Production of Polyisocyanate Composition PB3) Polyisocyanate composition PB3' was obtained in the same manner as in Example 1, except that 25 parts by mass of I-BuOH was added instead of 30.0 parts by mass of 2EH, and the reaction was stopped when the yield reached 55% by mass.

[0252] To the resulting 480.0 g of polyisocyanate composition PB3', 20.0 g of HES / TPA obtained in Synthesis Example 1 was added, and the mixture was stirred at 105° C. for 5 hours to carry out a reaction, thereby obtaining polyisocyanate composition PB3. The physical properties and evaluation results of the obtained polyisocyanate composition PB3 are shown in Table 4 below.

[0253] Comparative Example 4 (Production of Polyisocyanate Composition PB4) A polyisocyanate composition PB4' was obtained in the same manner as in Example 1, except that the reaction was stopped when the yield reached 45% by mass.

[0254] To the obtained 460 parts by mass of polyisocyanate composition PB4', 40 parts by mass of polyethylene glycol monomethyl ether (manufactured by Nippon Nyukazai Co., Ltd., product name "MPG-130") having an average number of ethylene oxide repeating units of 9.0 and 0.05 g of 2-ethylhexyl ash phosphate (manufactured by Johoku Chemical Industry Co., Ltd., product name "JP-508T") were added, and the mixture was stirred at 110°C for 4 hours to carry out a reaction, thereby obtaining polyisocyanate composition PB4. The physical properties and evaluation results of the obtained polyisocyanate composition PB4 are shown in Table 4 below.

[0255] In the following Tables 1 to 4, the mass fraction of the anionic compound (b) is the mass fraction of the anionic compound (b) relative to the total mass of the polyisocyanate composition.

[0256] [Table 1]

[0257] [Table 2]

[0258] [Table 3]

[0259] [Table 4]

[0260] As can be seen from Tables 1 to 3, polyisocyanate compositions PA1 to PA20 (Examples 1 to 20) containing polyisocyanate derived from diisocyanate (a), anionic compound (b), and alcohol (c), and blocked polyisocyanate composition BL1 (Example 21) had good dispersibility when blended with an aqueous base, and when formed into a coating film, had excellent gloss, water resistance, acid resistance, weather resistance, self-repairing property, and adhesion.

[0261] As can be seen from Table 1, in a comparison of polyisocyanate compositions PA1 to 5 (Examples 1 to 5) with different average numbers of hydroxy groups per molecule of alcohol (c) and number-average molecular weights, polyisocyanate composition PA1, in which the average number of hydroxy groups per molecule of alcohol (c) was 1.0 and the number-average molecular weight was 130, tended to have better acid resistance when formed into a coating film. Polyisocyanate compositions PA2 to 5, in which the average number of hydroxy groups per molecule of alcohol (c) was 2.0 or more and 3.0 or less and the number-average molecular weight was 250 or more and 6,500 or less, tended to have better self-repairing properties and adhesion when formed into a coating film.

[0262] As can be seen from Tables 1 and 2, in a comparison between polyisocyanate compositions PA6 to 8 and 11 to 14 (Examples 6 to 8 and 11 to 14), which contain polyester polyol as alcohol (c), and polyisocyanate compositions PA2 to 5, which contain polyether polyol, polyisocyanate compositions PA6 to 8 and 11 to 14, which contain polyester polyol, tended to have better acid resistance and weather resistance when formed into a coating film.

[0263] As can be seen from Table 1, in a comparison between polyisocyanate composition PA9 (Example 9), in which the molar fraction of allophanate groups relative to the total amount of isocyanurate groups and allophanate groups is 35.0%, and polyisocyanate composition PA10 (Example 10), in which the molar fraction is 80.0%, polyisocyanate composition PA9 tended to have better water resistance when formed into a coating film.

[0264] From Table 2, in comparison between polyisocyanate compositions PA11 to 16 (Examples 11 to 16) in which the mass ratio (I) / (II) of polyisocyanate (I) to polyisocyanate (II) is 15 / 85 or more and 85 / 15 or less, and polyisocyanate compositions PA2, 7, and 8 (Examples 2, 7, and 8) which do not contain polyisocyanate (II), it was found that polyisocyanate compositions PA11 to 14 tended to have better water resistance, acid resistance, and weather resistance when formed into a coating film.

[0265] As can be seen from Tables 1 and 3, in a comparison of polyisocyanate compositions PA1, 17, and 18 (Examples 1, 17, and 18) in which the mass fractions of the anionic compound (b) were 3.5 mass%, 1.0 mass%, and 7.2 mass%, respectively, polyisocyanate composition PA1 tended to have better dispersibility when blended with an aqueous base resin, and to have better gloss, water resistance, and acid resistance when formed into a coating film.

[0266] From Tables 1 and 3, in a comparison between polyisocyanate composition PA6 (Example 6) in which diisocyanate (b) is HDI and polyisocyanate composition PA19 (Example 19) in which diisocyanate (b) is PDI, polyisocyanate composition PA6 showed better dispersibility when blended with an aqueous base resin, and tended to have better self-repairing properties and adhesion when formed into a coating film.

[0267] On the other hand, as can be seen from Table 4, the polyisocyanate composition PB1 (Comparative Example 1) in which the diisocyanate (a) is an alicyclic diisocyanate, the polyisocyanate composition PB2 (Comparative Example 2) which does not contain the alcohol (c), and the polyisocyanate composition PB3 (Comparative Example 3) in which the alcohol (c) is a monool and the molecular weight of the monool is less than 100 had poor self-repairing properties and adhesion when formed into a coating film. Furthermore, the polyisocyanate composition PB4 (Comparative Example 4) which does not contain the anionic compound (b) had poor water resistance and acid resistance when formed into a coating film. [Industrial Applicability]

[0268] The polyisocyanate composition and blocked polyisocyanate composition of the present embodiment provide a polyisocyanate composition and blocked polyisocyanate composition that exhibit good dispersibility when blended with an aqueous base resin and, when formed into a coating film, exhibit excellent gloss, water resistance, acid resistance, self-repairing property, adhesion, and weather resistance. Furthermore, a coating composition and a coated substrate can be provided using the polyisocyanate composition or the blocked polyisocyanate composition.

Claims

1. A polyisocyanate composition comprising a polyisocyanate derived from a chain aliphatic diisocyanate (a), an anionic compound (b), and an alcohol (c), the anionic compound (b) contains an active hydrogen group, and the mass fraction of the anionic compound (b) relative to the total mass of the polyisocyanate composition is 1.0 mass% or more and 8.0 mass% or less; the alcohol (c) has an average number of hydroxy groups per molecule of 1.0 or more and 6.0 or less, and a number average molecular weight of 100 or more and 7,000 or less; The polyisocyanate composition contains an isocyanurate group and an allophanate group, and the molar fraction of the allophanate group relative to the total amount of the isocyanurate group and the allophanate group is 0.005 mol / mol or more and 0.850 mol / mol or less.

2. 2. The polyisocyanate composition according to claim 1, wherein the alcohol (c) has an average number of hydroxyl groups per molecule of 2.0 or more and 4.0 or less, and a number average molecular weight of 100 or more and 4,500 or less.

3. The polyisocyanate composition according to claim 1 or 2, wherein the alcohol (c) is either or both of a polyether polyol and a polyester polyol.

4. The polyisocyanate composition according to claim 3, wherein the alcohol (c) comprises a polyether polyol, and the polyether polyol is a polyether polyol having at least one oxyalkylene group selected from the group consisting of an oxypropylene group and an oxytetramethylene group.

5. The polyisocyanate composition of claim 3 , wherein the alcohol (c) comprises a polyester polyol, and the polyester polyol is a polycaprolactone polyol.

6. 3. The polyisocyanate composition according to claim 1, wherein the molar fraction of allophanate groups relative to the total amount of isocyanurate groups and allophanate groups is 0.010 mol / mol or more and 0.700 mol / mol or less.

7. 3. The polyisocyanate composition according to claim 1, wherein the polyisocyanate contains a polyisocyanate (I) and a polyisocyanate (II), the polyisocyanate (I) is derived from the chain aliphatic diisocyanate (a) and the anionic compound (b), and the polyisocyanate (II) is derived from the chain aliphatic diisocyanate (a) and the alcohol (c).

8. The polyisocyanate composition according to claim 7, wherein the mass ratio of the polyisocyanate (I) to the polyisocyanate (II) [(I) / (II)] is 10 / 90 or more and 90 / 10 or less.

9. The polyisocyanate composition of claim 7, wherein the polyisocyanate (I) comprises a reaction product with the alcohol (c).

10. The polyisocyanate composition according to claim 1 or 2, which has a number average molecular weight of 500 or more and 3,000 or less.

11. 3. The polyisocyanate composition according to claim 1, wherein the viscosity at 25°C in the absence of an organic solvent is 500 mPa·s or more and 50,000 mPa·s or less.

12. The polyisocyanate composition according to claim 1 or 2, wherein the isocyanate group content is 8.0% by mass or more and 22.0% by mass or less.

13. 3. The polyisocyanate composition according to claim 1, wherein the anionic compound (b) is one or more sulfonic acids selected from the group consisting of sulfonic acids containing a hydroxyl group and sulfonic acids containing an amino group.

14. The polyisocyanate composition according to claim 13, wherein the sulfonic acid group of the anionic compound (b) is neutralized with an inorganic base or an organic amine compound.

15. The polyisocyanate composition according to claim 14, wherein the anionic compound (b) is a compound represented by the following general formula (1): 【Chemical 1】 (In general formula (1), R １１ R is a hydrocarbon group having 1 to 10 carbon atoms which may contain at least one selected from the group consisting of a hydroxyl group, an ether bond, an ester bond, a carbonyl group, and an imino group. １１ may contain a ring structure. The ring structure is an aromatic ring, a 5- or 6-membered ring containing two nitrogen atoms, or a 5- or 6-membered ring containing a nitrogen atom and an oxygen atom.

16. 3. A blocked polyisocyanate composition, wherein the isocyanate groups of the polyisocyanate composition according to claim 1 or 2 are blocked with a thermally dissociable blocking agent.

17. A coating composition comprising the polyisocyanate composition of claim 1 or 2.

18. A coated substrate coated with the coating composition of claim 17.

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