Polyisocyanate composition, coating composition, and coated substrate

Abstract

To provide a polyisocyanate composition which offers high chromaticity, reduces cloudiness upon storage after being diluted with a hydrophilic solvent, exhibits superior dispersion upon mixing with a main agent, and also achieves superior gloss and alkali resistance when formed into a coating film.SOLUTION: A polyisocyanate composition comprises a hydrophilic polyisocyanate compound, wherein the hydrophilic polyisocyanate compound is a reaction product of a polyisocyanate and an anionic compound having a sulfonic acid group, the polyisocyanate is derived from a diisocyanate, the hydrophilic polyisocyanate compound includes an isocyanurate trimer (A) and a polyisocyanate compound (B) that is bound to the anionic compound through an allophanate group, and the mass ratio [(B) / (A)] of the polyisocyanate compound (B) to the isocyanurate trimer (A) is 50 / 10000 or less.SELECTED DRAWING: None

Description

Technical Field

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

Background Art

[0002] In recent years, from the viewpoints of global environmental protection, labor safety and hygiene, etc., in order to reduce the amount of organic solvents used, the development of water-based coating agents has been actively carried out. A two-component curable resin composition composed of a main agent containing a hydroxyl group (so-called polyol) and a polyisocyanate as a curing agent can be cured even at room temperature and exhibits excellent mechanical properties, chemical resistance, durability, etc. Therefore, it is widely used in various applications such as paints and adhesives. In order to be used as a water-based two-component curable resin composition using polyisocyanate as a curing agent, a large number of water-dispersible polyisocyanates modified with anionic compounds to impart hydrophilicity have been reported so far.

[0003] For example, Patent Documents 1 and 2 disclose a curing agent for a water-based two-component curable resin having compatibility with a water-based main agent by containing a polyisocyanate having a specific anion structure and a specific viscosity.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] Patent Documents 1 and 2 disclose the application of a polyisocyanate composition having an anionic hydrophilic group to an aqueous paint. However, the polyisocyanate composition having an anionic hydrophilic group has a high viscosity and requires solvent dilution, but there is a problem that turbidity occurs during storage after solvent dilution.

[0006] The present invention has been made in view of the above circumstances, and an object thereof is to provide a polyisocyanate composition having a high chromaticity, reduced turbidity during storage after dilution with a hydrophilic solvent, good dispersibility when blended with a main agent, and excellent gloss and alkali resistance when formed into a coating film.

Means for Solving the Problems

[0007] That is, the present invention includes the following aspects. [1] A polyisocyanate composition containing a hydrophilic polyisocyanate compound, wherein the hydrophilic polyisocyanate compound is a reaction product of a polyisocyanate and an anionic compound having a sulfonic acid group, and the polyisocyanate is derived from one or more diisocyanates selected from the group consisting of aliphatic diisocyanates, alicyclic diisocyanates, and aromatic diisocyanates. The hydrophilic polyisocyanate compound includes an isocyanurate trimer (A) and a polyisocyanate compound (B) bonded to the anionic compound via an allophanate group, and the mass ratio [(B) / (A)] of the polyisocyanate compound (B) to the isocyanurate trimer (A) is 50 / 10000 or less. Polyisocyanate composition. [2] The polyisocyanate composition according to [1], wherein the polyisocyanate contains a reaction product with an alcohol. [3] The polyisocyanate composition according to [2], wherein the alcohol has an average number of hydroxyl groups per molecule of 2.0 or more and 3.5 or less and a number average molecular weight of 450 or less. [4] The polyisocyanate composition according to [2] or [3], wherein the mass fraction of the alcohol in the polyisocyanate composition is 4.5% or less. [5] The polyisocyanate composition according to any one of [1] to [4], wherein the anionic compound is at least one sulfonic acid selected from the group consisting of sulfonic acids containing a hydroxyl group and sulfonic acids containing an amino group. [6] The polyisocyanate composition according to any one of [1] to [5], wherein the sulfonic acid group of the anionic compound is neutralized with an inorganic base or an organic amine compound. [7] The polyisocyanate composition according to any one of [1] to [6], wherein the anionic compound is a compound represented by the following general formula (1). [Chemical formula] (In general formula (1), R 11 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. R 11 may contain a ring structure. The ring structure is an aromatic ring, a 5-membered or 6-membered ring containing two nitrogen atoms, or a 5-membered or 6-membered ring containing a nitrogen atom and an oxygen atom.) [8] The polyisocyanate composition according to any one of [1] to [7], wherein the anionic compound is a compound represented by the following general formula (2). [Chemical formula] (In general formula (2), R 21 and R 22 are, independently of each other, a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms which may contain a hydroxyl group. At least one of R 22 and R 23 is a hydrogen atom. R 23 is a hydrocarbon group having 1 to 12 carbon atoms which may contain a hydroxyl group.) [9] A coating composition containing the polyisocyanate composition according to any one of [1] to [8].

[10] A coated substrate coated with the coating composition according to [9]. [Advantages of the Invention]

[0008] According to the polyisocyanate composition of the above aspect, it is possible to provide a polyisocyanate composition having a high chromaticity, reduced turbidity during storage after dilution with a hydrophilic solvent, excellent dispersibility when further blended with a main agent, and excellent gloss when formed into a coating film.

Embodiments for Carrying Out the Invention

[0009] Hereinafter, embodiments for carrying out the present invention (hereinafter referred to as "the present embodiment") will be described in detail. It should be noted that the present invention is not limited to the following embodiments, and various modifications can be made and implemented within the scope of the gist thereof.

[0010] <Polyisocyanate Composition> The polyisocyanate composition of the present embodiment contains a hydrophilic polyisocyanate compound. The hydrophilic polyisocyanate compound is a reaction product obtained by reacting a polyisocyanate with an anionic compound having a sulfonic acid group. The polyisocyanate is derived from one or more diisocyanates selected from the group consisting of aliphatic diisocyanates, alicyclic diisocyanates, and aromatic diisocyanates. The hydrophilic polyisocyanate compound contains an isocyanurate trimer (A), and the mass ratio [(B) / (A)] of the polyisocyanate compound (B) bonded to the anionic compound via an allophanate group to the isocyanurate trimer (A) is 50 / 10000 or less. Hereinafter, the "hydrophilic polyisocyanate compound" may be described as the "hydrophilic compound".

[0011] The polyisocyanate composition of this embodiment may contain a raw material polyisocyanate that has not reacted with the anionic compound (hereinafter also referred to as "unreacted raw material polyisocyanate") and the anionic compound that has not reacted with the raw material polyisocyanate (hereinafter also referred to as "unreacted anionic compound"). In addition, various physical properties or characteristics of the polyisocyanate composition of this embodiment described later, unless otherwise specified, are those of a state containing a polyisocyanate (hereinafter also referred to as "modified polyisocyanate") obtained by the reaction of the raw material polyisocyanate and the anionic compound, unreacted raw material polyisocyanate, and unreacted anionic compound.

[0012] Details of each component will be described below.

[0013] ≪Polyisocyanate≫ The polyisocyanate constituting the hydrophilic polyisocyanate compound is derived from one or more diisocyanates selected from the group consisting of aliphatic diisocyanates, alicyclic diisocyanates, and aromatic diisocyanates. Here, the "polyisocyanate" means a compound obtained by reacting diisocyanates with each other and, if necessary, a compound other than diisocyanates (for example, alcohol, water, amine, etc.).

[0014] Examples of the aliphatic diisocyanate include, but are not limited to, 1,4-diisocyanatobutane, 1,5-diisocyanatopentane, 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.

[0015] Examples of alicyclic diisocyanates include, but are not limited to, 1,3- or 1,4-bis(isocyanatomethyl)cyclohexane (hereinafter also referred to as "hydrogenated XDI"), 1,3- or 1,4-diisocyanatocyclohexane, 3,5,5-trimethyl-1-isocyanato-3-(isocyanatomethyl)cyclohexane (hereinafter also referred to as "IPDI"), 4,4'-diisocyanato-dicyclohexylmethane (hereinafter also referred to as "hydrogenated MDI"), 2,5- or 2,6-diisocyanatomethylnorbornane, and the like.

[0016] Among them, aliphatic diisocyanates are preferred in terms of weather resistance, chemical resistance, and scratch resistance, and particularly HDI is preferred.

[0017] The polyisocyanates are not particularly limited, and examples thereof include polyisocyanates shown in the following (a) to (h). (a) A polyisocyanate having a uretdione group obtained by cyclodimerizing two isocyanate groups; (b) A polyisocyanate having an isocyanurate group or an iminooxadiazinedione group obtained by cyclotrimerizing three isocyanate groups; (c) A polyisocyanate having a biuret group obtained by reacting three isocyanate groups with one water molecule; (d) A polyisocyanate having an oxadiazinetrione group obtained by reacting two isocyanate groups with one molecule of carbon dioxide; (e) A polyisocyanate having a plurality of urethane groups obtained by reacting one isocyanate group with one hydroxyl group; (f) A polyisocyanate having an allophanate group obtained by reacting two isocyanate groups with one hydroxyl group; (g) A polyisocyanate having an acylurea group obtained by reacting one isocyanate group with one carboxyl group; (h) A polyisocyanate having a urea group obtained by reacting one isocyanate group with one primary or secondary amine

[0018] Among them, the polyisocyanate used in the hydrophilic polyisocyanate compound preferably satisfies the above (b), and more preferably is a polyisocyanate having an isocyanurate group.

[0019] (Isocyanurate group) The isocyanurate group is a functional group obtained by cyclotrimerizing three isocyanate groups, and refers to the structure represented by the following formula (3).

[0020] [Chemical formula]

[0021] In a state where unreacted diisocyanate is removed, the content of the isocyanurate group is preferably 30 mol% or more and 100 mol% or less with respect to the total number of moles (100 mol%) of the isocyanurate group, allophanate group, iminooxadiazinedione group, and uretdione group. The lower limit is more preferably 40 mol%, and even more preferably 50 mol%. The upper limit is more preferably 95 mol%, and even more preferably 90 mol%. When the content of the isocyanurate group is within the above range, the resulting coating film tends to have excellent chemical resistance and weather resistance.

[0022] The content of each structure derived from the isocyanate group 13 can be determined by 13C-NMR measurement. Specifically, in the 13C-NMR measurement (measurement solvent: chloroform-d, sample concentration: 60 mass / volume%, observation frequency: 150 MHz, number of integrations: 10,000 times) using Biospin Avance600 (trade name) manufactured by Bruker, when the aliphatic diisocyanate is HDI, a signal of the carbon atom of the carbonyl group in the 6-membered ring is observed at around 148.6 ppm for the isocyanurate ring structure. Since there are three same carbon atoms in the structure, 1 / 3 of the integration value corresponds to the molar fraction of the structure. 13

[0023] (Allophanate group) An allophanate group is a functional group formed by the reaction of a hydroxyl group and an isocyanate group, and refers to a structure represented by the following formula (4).

[0024]

Chemical formula

[0025] In the polyisocyanate composition of the present embodiment, the molar ratio of the allophanate group is preferably 0.1 mol% or more and 20.0 mol% or less, and more preferably 0.5 mol% or more and 16.0 mol% or less, based on the total number of moles (100 mol%) of the isocyanurate group, allophanate group, iminooxadiazinedione group, and uretdione group. When the molar ratio of the allophanate group is within the above range, the scratch resistance of the coating composition tends to be excellent. The molar ratio of the allophanate group can be determined, for example, 13 by 13C-NMR measurement.

[0026] (Iminooxadiazinedione group) An iminooxadiazinedione group is a functional group obtained by cyclotrimerizing three isocyanate groups, and refers to a structure represented by the following formula (5).

[0027]

Chemical formula

[0028] In the polyisocyanate composition of the present embodiment, the molar ratio of the iminooxadiazinedione group is preferably 0.1 mol% or more and 40.0 mol% or less, and more preferably 0.5 mol% or more and 30.0 mol% or less, based on the total number of moles (100 mol%) of the isocyanurate group, allophanate group, iminooxadiazinedione group, and uretdione group. When the molar ratio of the iminooxadiazinedione group is within the above range, the viscosity is reduced and the dispersibility of the coating composition is excellent. The molar ratio of the iminooxadiazinedione group is13 It can be determined by 13C-NMR measurement.

[0029] (uretdione group) The uretdione group is a functional group obtained by cyclodimerizing two isocyanate groups, and refers to the structure represented by the following formula (6). The polyisocyanate having a uretdione group has a low viscosity and the cured coating film has good scratch resistance.

[0030] [Chemical formula]

[0031] In the polyisocyanate composition of the present embodiment, the molar ratio of the uretdione group is preferably 0.5 mol% or more and 30.0 mol% or less, and more preferably 1.0 mol% or more and 25.0 mol% or less, based on the total number of moles (100 mol%) of the isocyanurate group, iminooxadiazinedione group, allophanate group, and uretdione group. When the molar ratio of the uretdione group is within the above range, the coating film obtained as a coating composition is excellent in gloss and alkali resistance. The molar ratio of the uretdione group can be determined, for example, by 13 13C-NMR measurement, or 1 1H-NMR measurement.

[0032] Furthermore, from the viewpoint of reducing the viscosity change during blending, the mass fraction of the uretdione dimer obtained by cyclodimerizing two diisocyanates is preferably 0.01 mass% or more and 20.0 mass% or less.

[0033] The upper limit value of the mass fraction of the uretdione dimer is more preferably 18.0 mass% or less, and even more preferably 15.0 mass% or less, from the viewpoint of improving the gloss and alkali resistance of the coating film. Also, from the viewpoint of reducing the viscosity, it is more preferably 0.1 mass% or more, and even more preferably 0.5 mass% or more. The mass fraction of the uretdione dimer can be determined by GPC.

[0034] (Other bonding groups) In addition to the bonding groups described above, the polyisocyanate composition of the present embodiment may further have one or more bonding groups selected from the group consisting of urethane groups, biuret groups, urea groups, acylurea groups, and oxadiazinetrione groups. In the polyisocyanate composition of the present embodiment, the total molar ratio of the other bonding groups is preferably 0.01 mol% or more and 10 mol% or less with respect to the total number of moles (100 mol%) of isocyanurate groups, iminooxadiazinedione groups, allophanate groups, and uretdione groups. The molar ratio of the other bonding groups can be determined, for example, 13 by C-NMR measurement, or 1 by H-NMR measurement.

[0035] The polyisocyanate may contain an aliphatic triisocyanate. Examples of the aliphatic triisocyanate include 1,3,6-triisocyanatohexane, 1,8-diisocyanato-4-isocyanatomethyloctane, 2-isocyanatoethyl-2,6-diisocyanato-hexanoate, and the like.

[0036] ≪Anionic Compound≫ The anionic compound is preferably at least one sulfonic acid selected from the group consisting of sulfonic acids containing a hydroxyl group and sulfonic acids containing an amino group. In the hydrophilic polyisocyanate compound contained in the polyisocyanate composition of the present embodiment, an anionic group derived from the anionic compound is introduced into a part of the isocyanate groups.

[0037] When the anionic compound 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 aspect of the present invention, the anionic compound is a compound represented by the following general formula (1).

[0038]

Chemical Formula

[0039] In the general formula (1), R 11 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. R 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.

[0040] The hydrocarbon group having 1 to 10 carbon atoms may be a divalent aliphatic hydrocarbon group having 1 to 10 carbon atoms, or a divalent aromatic hydrocarbon group having 6 to 10 carbon atoms. The divalent aliphatic hydrocarbon group having 1 to 10 carbon atoms is preferably a linear alkylene group having 1 to 6 carbon atoms. When it is a linear alkylene group having 1 to 6 carbon atoms, a part of the linear alkylene group may be a group containing a ring structure. The alkylene group having 1 to 6 carbon atoms may be linear or branched.

[0041] Among them, R 11 is preferably a linear alkylene group having 1 to 6 carbon atoms, a divalent aromatic hydrocarbon group (arylene group) having 6 to 10 carbon atoms, a divalent alkylene group having 1 to 6 carbon atoms containing an aromatic ring, a divalent alkylene group having 1 to 6 carbon atoms containing a 5- or 6-membered ring containing two nitrogen atoms, or a divalent alkylene group having 1 to 6 carbon atoms containing a 5- or 6-membered ring containing a nitrogen atom and an oxygen atom.

[0042] Preferred anionic compounds having a hydroxyalkylsulfonic acid group include, for example, 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, 2-hydroxy-3-morpholinopropanesulfonic acid, and the like. These compounds are only a part of the preferred sulfonic acid (1), and the preferred sulfonic acid (1) is not limited to these. Also, one of these sulfonic acids (1) may be used, or two or more thereof may be used in combination.

[0043] Among them, as the anionic compound having a hydroxy group, it 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 have good gloss of the coating film.

[0044] In addition, when the polyisocyanate composition of this embodiment contains two or more amine salts of sulfonic acid, the sulfonic acids (1) may be the same as or different from each other.

[0045] Also, the sulfonic acid used for the polyisocyanate containing a sulfonic acid anion group in the molecule may form a salt with an amine compound described later.

[0046] When the anionic compound is a sulfonic acid having an amino group, for example, compounds represented by the following general formula (2) (hereinafter abbreviated as "sulfonic acid (2)") and the like can be mentioned. That is, in one aspect of the present invention, the anionic compound is a compound represented by the following general formula (2).

[0047] [Chemical formula]

[0048] In the general formula (2), R 21 and R 23 are, independently of each other, a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms which may contain a hydroxyl group. At least one of R 21 and R 23 is a hydrogen atom. R 22 is a hydrocarbon group having 1 to 12 carbon atoms which may contain a hydroxyl group.

[0049] ·R 21 and R 23 In general formula (2), R 21 and R 23 are, independently of each other, a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms which may contain a hydroxyl group. R 21 and R 23 may be the same as or different from each other. At least one of R 21 and R 23 is a hydrogen atom. That is, when R 21 is a hydrocarbon group having 1 to 12 carbon atoms which may contain a hydroxyl group, R 23 is a hydrogen atom. Also, when R 23 is a hydrocarbon group having 1 to 12 carbon atoms which may contain a hydroxyl group, R 21 is a hydrogen atom. Also, both R 21 and R 23 may be hydrogen atoms.

[0050] The hydrocarbon group having 1 to 12 carbon atoms may be a monovalent aliphatic hydrocarbon group having 1 to 12 carbon atoms or a monovalent aromatic hydrocarbon group having 6 to 12 carbon atoms. The monovalent aliphatic hydrocarbon group having 1 to 12 carbon atoms is preferably a linear or branched alkyl group having 1 to 6 carbon atoms or a cyclic alkyl group having 3 to 6 carbon atoms. The linear or branched alkyl group having 1 to 6 carbon atoms may be linear or branched.

[0051] Among them, R 21 and R 23 are preferably a hydrogen atom, a linear alkyl group having 1 to 6 carbon atoms, or a cyclic alkyl group having 3 to 6 carbon atoms, respectively.

[0052] ·R 22 R 22 is a hydrocarbon group having 1 to 12 carbon atoms which may contain a hydroxyl group. The hydrocarbon group having 1 to 12 carbon atoms may be a divalent aliphatic hydrocarbon group having 1 to 12 carbon atoms, or a divalent aromatic hydrocarbon group having 6 to 12 carbon atoms. The divalent aliphatic hydrocarbon group having 1 to 12 carbon atoms is preferably a linear alkylene group having 1 to 12 carbon atoms. The linear alkyl group having 1 to 12 carbon atoms may be linear or branched. Among them, R 22 is preferably a divalent linear alkylene group having 1 to 6 carbon atoms, or a divalent aromatic hydrocarbon group (arylene group) having 6 to 10 carbon atoms.

[0053] Preferred sulfonic acids (2) include, for example, 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 only a part of the preferred sulfonic acids (2), and the preferred sulfonic acids (2) are not limited to these. Also, one of these sulfonic acids (2) may be used, or two or more thereof may be used in combination.

[0054] Among them, as the sulfonic acid having an amino group, 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 is preferably used.

[0055] In one aspect of the present invention, it is preferable that the sulfonic acid group of the anionic compound is neutralized with an inorganic base or an organic amine compound.

[0056] Examples of the inorganic base include alkali metals such as lithium, sodium, potassium, rubidium, and cesium; alkaline earth metals such as magnesium, calcium, strontium, and barium; metals such as manganese, iron, cobalt, nickel, copper, zinc, silver, cadmium, lead, and aluminum; and ammonia.

[0057] Examples of the organic amine compound include linear tertiary amines such as trimethylamine, triethylamine, tripropylamine, tributylamine, trioctylamine, trilaurylamine, tritridecylamine, tristearylamine; branched tertiary amines such as triisopropylamine, triisobutylamine, tri-2-ethylhexylamine, tribranched tridecylamine; tertiary amines having mixed hydrocarbon groups such as N,N-dimethylethylamine, 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, N,N-diethyloctylamine, N,N-diethyl-2-ethylhexylamine, N,N-diethyllaurylamine, N,N-diisopropylmethylamine, N,N-diisopropylethylamine, N,N-diisopropylbutylamine, N,N-diisopropyl-2-ethylhexylamine; alicyclic tertiary amines such as N,N-dimethylcyclohexylamine, N,N-diethylbenzylamine, N,N-diethylcyclohexylamine, N,N-dicyclohexylmethylamine, N,N-dicyclohexylethylamine, tricyclohexylamine; tertiary amines having aromatic ring substituents such as N,N-dimethylbenzylamine, N,N-diethylbenzylamine, N,N-dibenzylmethylamine, tribenzylamine, N,N-dimethyl-4-methylbenzylamine, N,N-dimethylphenylamine, N,N-diethylphenylamine, N,N-diphenylmethylamine; 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, quinuclidine, etc.These organic amine compounds may be used alone or in combination of two or more.

[0058] Among them, tertiary amines having 5 to 30 carbon atoms are preferable. Specifically, for example, 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, N,N-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, quinoline, etc. may be mentioned. These preferable organic amine compounds may be used alone or in combination of two or more.

[0059] In addition, when the polyisocyanate composition of this embodiment contains two or more amine salts of sulfonic acid, the sulfonic acids (2) may be the same as or different from each other.

[0060] Anionic compounds containing active hydrogen groups such as carboxyl groups and amino groups have high emulsifying power, so a high emulsifying effect can be obtained with a small amount. In order to disperse polyisocyanate in water, when it is modified with an anionic compound (introducing a hydrophilic group derived from a hydrophilic compound into the polyisocyanate), the amount of the anionic compound used can be small, so the modification ratio does not become too high, and the physical properties of the coating film (gloss and alkali resistance) are less likely to deteriorate.

[0061] In the polyisocyanate composition of this embodiment, the mass fraction of the anionic compound bonded to the hydrophilic polyisocyanate compound is preferably 0.1% by mass or more and 13.0% by mass or less with respect to the total mass (100% by mass) of the polyisocyanate composition. Further, from the viewpoint of achieving both dispersibility and water resistance and weather resistance, 0.1% by mass or more and 9.0% by mass or less is preferable, and 0.5% by mass or more and 6.0% by mass or less is more preferable.

[0062] (Alcohol component) The polyisocyanate may contain a reaction product with alcohol. Alcohol is an inducing component of the polyisocyanate composition.

[0063] The alcohol preferably has an average number of hydroxyl groups per molecule of 2.0 or more and 3.5 or less and a number average molecular weight of 450 or less. From the viewpoints of the chromaticity, chemical resistance, and dispersibility with the main agent of the polyisocyanate, the average number of hydroxyl groups of the alcohol is preferably 2.0 or more and 3.0 or less, and more preferably 2.0 or more and 2.5 or less. Also, from the viewpoint of dispersibility with the main agent, the number average molecular weight is preferably 400 or less, and more preferably 350 or less.

[0064] Examples of alcohols that satisfy the average number of hydroxyl groups and the number-average molecular weight include diols, triols, tetraols, and polymerized alcohols. Examples of diols include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 2-methyl-1,2-propanediol, 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, 2,5-hexanediol, 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, etc. Examples of triols include glycerin, trimethylolpropane, etc. Examples of tetraols include pentaerythritol, etc.

[0065] Examples of polymerized alcohols include polyester polyols, polyether polyols, acrylic polyols, polyolefin polyols, polycarbonate diols, etc.

[0066] Examples of the polyester polyol include a polyester polyol 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 as a mixture, and a polyhydric alcohol selected from the group consisting of ethylene glycol, propylene glycol, diethylene glycol, neopentyl glycol, trimethylolpropane, glycerin, etc., alone or as a mixture, and polycaprolactones obtained by ring-opening polymerization of ε-caprolactone using a polyhydric alcohol, etc.

[0067] Examples of the polyether polyol include polyether polyols obtained by randomly or block-adding a single or a mixture of alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, cyclohexene oxide, and styrene oxide to a single or a mixture of polyhydric hydroxy compounds using strong basic catalysts such as hydroxides, alcoholates, and alkylamines of lithium, sodium, potassium, etc., and complex metal cyanide compound complexes such as metal porphyrins and zinc hexacyanocobaltate complexes, further polyether polyols obtained by reacting alkylene oxides with polyamine compounds such as ethylenediamines, and so-called polymer polyols obtained by polymerizing acrylamide, etc. using these polyethers as a medium.

[0068] The polycarbonate diol has a structural unit in which two alcohol groups and one carbonate group are dehydrated and condensed, repeating. Further, examples of the polycarbonate diol include those obtained by copolymerizing a first diol having 2 to 20 carbon atoms, a second diol having 2 to 20 carbon atoms (hereinafter also simply referred to as "two kinds of diols"), and a carbonate compound.

[0069] These alcohols may be used alone or in combination of a plurality.

[0070] The mass fraction of the alcohol in the polyisocyanate composition of the present embodiment is preferably 4.5% by mass or less. More preferably, it is 0.01% by mass or more and 4.5% by mass or less. Further preferably, from the viewpoints of chromaticity and dispersibility, it is 0.1% by mass or more and 2.5% by mass or less.

[0071] ≪Method for Producing Polyisocyanate Component Having Each Bonding Group≫ (Method for Producing Polyisocyanate Component Containing Isocyanurate Group) The catalyst for deriving a polyisocyanate component containing an isocyanurate group from a diisocyanate component is not particularly limited, but those showing basicity are preferable. Specifically, hydroxides and organic weak acid salts of tetraalkylammonium, hydroxides and organic weak acid salts of hydroxyalkylammonium, alkali metal salts of alkylcarboxylic acids, metal alcoholates, aminosilyl group-containing compounds, Mannich bases, combined use of tertiary amines and epoxy compounds, phosphorus compounds, etc. may be mentioned.

[0072] Examples of the tetraalkylammonium include tetramethylammonium, tetraethylammonium and the like.

[0073] Examples of the organic weak acid include acetic acid, capric acid and the like.

[0074] Examples of the hydroxyalkylammonium include trimethylhydroxypropylammonium, trimethylhydroxyethylammonium, triethylhydroxypropylammonium, triethylhydroxyethylammonium and the like.

[0075] Examples of the alkylcarboxylic acid include acetic acid, caproic acid, octylic acid, myristic acid and the like.

[0076] Examples of the alkali metal salt include tin, zinc, lead and the like.

[0077] Examples of the metal alcoholate include sodium alcoholate, potassium alcoholate, and the like.

[0078] Examples of the amino silyl group-containing compound include hexamethyldisilazane and the like.

[0079] Examples of the phosphorus-based compound include tributylphosphine and the like.

[0080] The usage amount of these catalysts is preferably 10 mass ppm or more and 10000 mass ppm or less with respect to the total mass of the diisocyanate (and alcohol if necessary) as the raw material. Further, in order to terminate the isocyanuration reaction, the catalyst may be inactivated by adding an acidic substance for neutralizing the catalyst, thermal decomposition, chemical decomposition, or the like. Examples of the acidic substance for neutralizing the catalyst include phosphoric acid, acidic phosphate ester, and the like.

[0081] The yield of the polyisocyanate component generally tends to be 10 mass% or more and 70 mass% or less. The polyisocyanate component obtained in a higher yield tends to have a higher viscosity. The yield can be calculated from the ratio of the mass of the obtained polyisocyanate component to the total mass of the raw material components.

[0082] The reaction temperature of the isocyanuration reaction is not particularly limited, but is preferably 50°C or higher and 200°C or lower, and more preferably 50°C or higher and 150°C or lower. When the reaction temperature is at or above the lower limit value, the reaction tends to proceed more easily, and when the reaction temperature is at or below the upper limit value, side reactions that cause coloring can be more effectively suppressed.

[0083] After completion of the isocyanuration reaction, it is preferable to remove unreacted diisocyanate by means of thin-film evaporator, extraction or the like. Even when the polyisocyanate component contains unreacted diisocyanate, the content of diisocyanate is preferably 3.0% by mass or less, more preferably 1.0% by mass or less, and still more preferably 0.5% by mass or less based on the total mass of the polyisocyanate component. When the concentration of residual unreacted diisocyanate is within the above range, the curability tends to be more excellent.

[0084] 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 still more preferably 0% by mass or more and 0.5% by mass or less.

[0085] (Process for producing a polyisocyanate component containing allophanate groups) The catalyst for inducing a polyisocyanate component containing allophanate groups from diisocyanate is not particularly limited. Examples thereof include alkyl carboxylates such as tin, lead, zinc, bismuth, zirconium, and zirconyl; organotin compounds such as tin 2-ethylhexanoate and dibutyltin dilaurate; organolead compounds such as lead 2-ethylhexanoate; organozinc 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.

[0086] In addition, the above-described isocyanuration reaction catalyst can also serve as an allophanatization reaction catalyst. When the allophanatization reaction is carried out using the above-described isocyanuration reaction catalyst, a polyisocyanate component containing an isocyanurate group is of course produced. From the viewpoint of economical production, it is preferable to carry out the allophanatization reaction and the isocyanuration reaction using the above-described isocyanuration reaction catalyst as the allophanatization reaction catalyst.

[0087] The compounding amount of the above-mentioned allophanatization reaction catalyst is preferably 10 mass ppm or more and 1000 mass ppm or less with respect to the mass of the charged diisocyanate. The lower limit value is more preferably 20 mass ppm, still more preferably 40 mass ppm, and even more preferably 80 mass ppm. The upper limit value is more preferably 800 mass ppm, still more preferably 600 mass ppm, and even more preferably 500 mass ppm or less.

[0088] The compounding amount of the above-mentioned allophanatization reaction catalyst is, for example, 20 mass ppm or more and 800 mass ppm or less, 40 mass ppm or more and 600 mass ppm or less, 80 mass ppm or more and 500 mass ppm or less with respect to the mass of the charged diisocyanate.

[0089] Also, the allophanatization reaction temperature is preferably 40°C or more and 180°C or less. The lower limit value is more preferably 60°C, still more preferably 80°C, and even more preferably 100°C. The upper limit value is more preferably 160°C, still more preferably 140°C. When the allophanatization reaction temperature is at or above the above lower limit value, the reaction rate tends to be maintained higher. When the allophanatization reaction temperature is at or below the above upper limit value, coloring of the polyisocyanate component and the like tend to be more effectively suppressed.

[0090] The allophanatization reaction temperature is, for example, 80°C or more and 160°C or less, 100°C or more and 140°C or less.

[0091] The alcohol used for forming the allophanate group is preferably an alcohol formed only of carbon, hydrogen, and oxygen. Specific examples of the alcohol include, but are not limited to, for example, monoalcohol, polyol, and mixtures of these alcohols.

[0092] As the monoalcohol, specifically, for example, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-methyl-1-propanol, 2-butanol, 1-pentanol, 3-methyl-1-butanol, 2-methyl-1-butanol, 2,2-dimethyl-1-propanol, 2-pentanol, 3-methyl-2-butanol, 3-pentanol, 2-methyl-2-butanol, 1-hexanol, 2-methyl-1-pentanol, 3-methyl-1-pentanol, 4-methyl-1-pentanol, 2,2-dimethyl-1-butanol, 2-ethyl-1-butanol, 2-hexanol, 3-hexanol, 3-methyl-2-pentanol, 4-methyl-2-pentanol, 2-methyl-3-pentanol, 3,3-dimethyl-2-butanol, 1-heptanol, 2-heptanol, 3-heptanol, 4-heptanol, 1-octanol, 6-methyl-1-heptanol, 2-ethylhexanol can be mentioned. The monoalcohol may be used alone or in combination of two or more.

[0093] As the polyol, specifically, for example, dialcohols such as ethylene glycol, 1,3-butanediol, neopentyl glycol, 2-ethylhexanediol can be mentioned.

[0094] Also, it is possible to use the alcohol described in the claims as a raw material and derive it as a polyisocyanate component having an allophanate group.

[0095] ≪Method for producing polyisocyanate composition≫ The method for producing the polyisocyanate composition of this embodiment includes, for example, the following (1) to (3). (1) A method of performing the reaction of a diisocyanate and an anionic compound all at once. (2) A method of producing a polyisocyanate compound (I) derived from a diisocyanate component and performing the reaction with an anionic compound. (3) A method of producing a polyisocyanate compound (I) derived from a diisocyanate component, and mixing a component (II) derived from a reaction with an anionic compound and a polyisocyanate (III) derived from a diisocyanate in a desired mass ratio.

[0096] Among the above production methods, (2) is more preferable in terms of production simplicity. In this reaction step, the reaction temperature and reaction time can be appropriately determined according to the progress of the reaction. However, the reaction temperature is preferably 90 °C or higher and 130 °C or lower, and more preferably 100 °C or higher and 125 °C or lower. The reaction time is preferably 0.5 hours or more and 24.0 hours or less, and more preferably 1.0 hours or more and 12.0 hours or less.

[0097] Also, in the reaction step, a known catalyst may be used as appropriate. Specifically, as the catalyst, there are organotin compounds such as tin octoate, tin 2-ethyl-1-hexanoate, tin ethylcaproate, tin laurate, tin palmitate, dibutyltin oxide, dibutyltin dichloride, dibutyltin diacetate, dibutyltin dimaleate, dibutyltin dilaurate, dioctyltin diacetate, dioctyltin dilaurate; organozinc compounds such as zinc chloride, zinc octoate, zinc 2-ethyl-1-hexanoate, zinc 2-ethylcaproate, zinc stearate, zinc naphthenate, zinc acetylacetonate; organic titanium compounds; organic zirconium compounds; tertiary amines such as triethylamine, tributylamine, N,N-diisopropylethylamine, N,N-dimethylethanolamine; and diamines such as triethylenediamine, tetramethylethylenediamine, 1,4-diazabicyclo[2.2.2]octane. These may be used alone or in combination.

[0098] In the method for producing the polyisocyanate composition of this embodiment, a solvent may or may not be used. The solvent used in the method for producing the polyisocyanate composition of this 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.

[0099] 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 can be used alone or in combination.

[0100] (Polyisocyanate component) As a precursor of the hydrophilic polyisocyanate compound, a polyisocyanate component (I) derived from diisocyanate may be used. This polyisocyanate component (I) can be obtained by reacting it once in the presence of an excess of diisocyanate in the same manner as the method for producing the polyisocyanate component having each of the above-mentioned bonding groups, and removing the unreacted diisocyanate after the reaction. At that time, other bonding groups may be generated simultaneously with the desired bonding group generated under each condition.

[0101] (Physical properties of polyisocyanate component (I)) From the viewpoint of improving the dispersibility and pot life of the coating composition, and the appearance and water resistance of the coating film, the viscosity of the polyisocyanate component (I) at 25°C is preferably 300 mPa·s or more and 100,000 mPa·s or less.

[0102] From the viewpoint of improving curability and chemical resistance of the cured coating film, etc., the lower limit value of the viscosity is more preferably 350 mPa·s, and even more preferably 450 mPa·s. On the other hand, from the viewpoint of improving dispersibility and solvent dilutability, the upper limit of the viscosity is more preferably 9,000 mPa·s, and even more preferably 8,000 mPa·s.

[0103] The viscosity can be measured at 25°C with an E-type viscometer (manufactured by Tokimec, Inc.) using a standard rotor (1°34’×R24), for example.

[0104] In the state excluding the unreacted diisocyanate component, the isocyanate group content (NCO%) of the polyisocyanate component (I) is preferably 12% by mass or more and 25% by mass or less, more preferably 14% by mass or more and 24% by mass or less, and even more preferably 16% by mass or more and 24% by mass or less.

[0105] When the isocyanate group content is at least the above lower limit value, the water resistance, chemical resistance, and weather resistance of the coating film are further improved. On the other hand, when it is at most the above upper limit value, the dispersibility and solvent dilutability of the coating composition are further improved, and the appearance of the coating film becomes better.

[0106] The isocyanate group content (NCO%) can be measured by the titration method described in the examples below.

[0107] From the viewpoint of the solvent resistance of the coating film, the number average molecular weight of the polyisocyanate component (I) is preferably 450 or more and 2,000 or less, more preferably 500 or more and 1,800 or less, and even more preferably 550 or more and 1,500 or less.

[0108] The number average molecular weight can be measured using, for example, GPC.

[0109] From the viewpoints of the solvent resistance of the coating film and the isocyanate group retention rate, the average functionality of the polyisocyanate component (I) is preferably 1.8 or more and 6.2 or less, more preferably 2.0 or more and 5.6 or less, and even more preferably 2.5 or more and 4.6 or less.

[0110] The average functionality is the number of isocyanate functional groups statistically possessed by one molecule of the polyisocyanate compound, and can be calculated using the following formula from the number average molecular weight (Mn) and the isocyanate group content (NCO%) of the polyisocyanate compound.

[0111] [Average functionality] = Mn × NCO% / 4200

[0112] ≪Method for producing anionic compound≫ The neutralized salt of the acidic group bonded to the anionic compound used in the polyisocyanate composition of the present embodiment can be obtained by subjecting it to a neutralization reaction with a cationic compound such as an inorganic base or an organic amine compound. Further, when the neutralized salt is an amine salt of sulfonic acid, for example, it can be obtained by mixing a compound containing a sulfonic acid group and an amine compound and subjecting them to a neutralization reaction.

[0113] The neutralization reaction may be carried out in advance before reacting with the diisocyanate component or the polyisocyanate component, or may be carried out simultaneously. Alternatively, it may be carried out by adding an amine compound after reacting the polyisocyanate compound with a compound containing a sulfonic acid group.

[0114] When the active hydrogen group is a hydroxyl group, it is preferable to carry out the neutralization reaction in advance before reacting with the polyisocyanate compound. When the active hydrogen group is an amino group, it is preferable to carry out the neutralization reaction simultaneously when reacting with the polyisocyanate compound, or to carry out the reaction by adding an amine compound after reacting the polyisocyanate compound with a sulfonic acid having an active hydrogen group.

[0115] When the active hydrogen group is a hydroxyl group, in the neutralization reaction, the mixing ratio of the sulfonic acid having a hydroxyl group and the amine compound 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, and more preferably 0.8 or more and 1.5 or less.

[0116] When the neutralization reaction is carried out in advance, the temperature and time are appropriately determined according to the progress of the reaction. Usually, the temperature is preferably about 0°C or more and 100°C or less, and the mixing time is preferably about 10 minutes or more and 24 hours or less.

[0117] The solvent used in the preparation of the amine salt of the compound containing the sulfonic acid group is preferably water or a hydrophilic solvent. The hydrophilic solvent is not particularly limited, and examples thereof include alcohols, ether alcohols, ketones, amide solvents, and the like. These solvents can be used alone or in combination.

[0118] Examples of the alcohols include methanol, ethanol, propanol, butanol, isopropanol, and the like.

[0119] 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, dipropylene glycol monomethyl ether, and the like.

[0120] Examples of the ketones include acetone, methyl ethyl ketone, methyl isobutyl ketone, and the like.

[0121] Examples of the amide solvents include N,N-dimethylformamide, N,N-dimethylacetamide, and the like.

[0122] After the neutralization reaction, it is preferable to remove water or a hydrophilic solvent.

[0123] The hydrophilic polyisocyanate compound contains an isocyanurate trimer (A). The isocyanurate trimer (A) is a cyclic trimer composed of three diisocyanates and does not contain other compounds in its structure.

[0124] In the polyisocyanate composition of the present embodiment, it contains a polyisocyanate compound (B) bonded to an anionic compound via an allophanate group, and the mass ratio of the polyisocyanate compound (B) to the isocyanurate trimer (A) is 50 / 10000 or less, preferably 30 / 10000 or less, and more preferably 20 / 10000 or less. When the mass ratio of the polyisocyanate compound (B) is within the above range, turbidity is less likely to occur during storage after dilution with a hydrophilic solvent. There is no particular limitation on the lower limit, but it is preferably 1 / 10000 or more.

[0125] The polyisocyanate compound (B) includes those composed of two molecules of trimers and a sulfonate anion, or those composed of a sulfonate anion, a trimer, and a pentamer, or those composed of a sulfonic acid, a trimer, and other multimers. The above mass ratio is calculated from the areas of each peak based on the results of measuring LC-MS and UV-MS using "UPLC" of WATERS to obtain the mass ratio of the polyisocyanate compound (B) to the isocyanurate trimer (A).

[0126] The average number of isocyanates in the polyisocyanate composition of the present embodiment is preferably 2.0 or more and 6.0 or less. The average number of isocyanates is the number of isocyanate groups statistically possessed by one molecule of the polyisocyanate composition, and can be calculated using the following formula from the number average molecular weight (Mn) and the isocyanate group concentration (NCO group concentration) of the polyisocyanate compound.

[0127] [Average functionality]=Mn×NCO% / 4,200

[0128] The isocyanate group concentration (NCO group concentration) of the polyisocyanate composition is preferably 10.0% by mass or more and 24.0% by mass or less. Further, from the viewpoint of achieving both curability, hardness of the coating film, chemical resistance, and scratch resistance, 12.0% by mass or more and 23.0% by mass or less is more preferable, and 13.0% by mass or more and 22.0% by mass or less is even more preferable. The isocyanate group concentration (NCO group concentration) can be measured by the titration method described in the examples below.

[0129] The number average molecular weight of the polyisocyanate composition is preferably 400 or more and 3,000 or less. Further, from the viewpoint of achieving both solvent dilutability, extensibility, and weather resistance, 500 or more and 2,500 or less is more preferable, and 600 or more and 2,000 or less is even more preferable. The number average molecular weight can be measured using, for example, GPC.

[0130] ≪Other methods for producing polyisocyanate≫ Furthermore, the produced polyisocyanate compound may be modified with a high molecular polyol. The high molecular polyol is a compound having one or more hydroxyl groups, and examples thereof include long-chain polyols, specifically polyester polyols, polycarbonate polyols, polyether polyols, acrylic polyols, and copolyols thereof. These long-chain polyols may be used alone or in combination of two or more. The polyisocyanate may be further modified with an alcohol having one or more hydroxyl groups. The alcohol is a compound having one or more hydroxyl groups, and examples thereof include short-chain polyols and long-chain polyols. Specific examples of the short-chain polyol include 1,2-propylene glycol, 1,3-butylene glycol, neopentyl glycol, neopentyl glycol hydroxy pivalate, 2-methyl-1,3-propanediol, 2,3,5-trimethylpentanediol, ethylene glycol, diethylene glycol, 1,3-propanediol, 1,4-butylene diol, 1,5-pentanediol, 1,6-hexanediol, trimethylolpropane, glycerin, 1,1,7-trimethylolheptane, 1,2,7-trimethylolheptane, and the like. Examples of the long-chain polyol include polyester polyols, polycarbonate polyols, polyether polyols, acrylic polyols, and copolyols thereof. These polyols may be used alone or in combination of two or more.

[0131] <<Other Components>> The polyisocyanate composition of the present embodiment may contain other components. The other components are not particularly limited, and examples thereof include solvents, antioxidants, light stabilizers, polymerization inhibitors, surfactants, and antioxidants.

[0132] The solvent may be a hydrophilic solvent or a hydrophobic solvent. These solvents can be used alone or in combination.

[0133] The hydrophobic solvent is not particularly limited, and examples thereof include mineral spirit, solvent naphtha, LAWS (Low Aromatic White Spirit), HAWS (High Aromatic White Spirit), toluene, xylene, cyclohexane, esters, ketones, and amides.

[0134] Examples of the esters include ethyl acetate, butyl acetate, and the like.

[0135] Examples of the ketones include acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, and the like.

[0136] Examples of the amides include N,N-dimethylformamide, N,N-dimethylacetamide, and the like.

[0137] The hydrophilic solvent is not particularly limited, and examples thereof include alcohols, ethers, and esters of ether alcohols.

[0138] Examples of the alcohols include methanol, ethanol, propanol, isopropanol, 2-ethylhexanol, and the like.

[0139] Examples of the ethers include diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, dipropylene glycol dimethyl ether, and the like.

[0140] 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, dipropylene glycol monomethyl ether acetate, and the like.

[0141] In the polyisocyanate composition of the present embodiment, the content of the solvent is preferably 0% by mass or more and 90% by mass or less, more preferably 0% by mass or more and 70% by mass or less, and even more preferably 0% by mass or more and 50% by mass or less, based on the total mass of the polyisocyanate composition of the present embodiment, from the viewpoint of ease of dispersion.

[0142] In the polyisocyanate composition of the present embodiment, the total content of the antioxidant, the light stabilizer, the polymerization inhibitor, and the surfactant is preferably 0% by mass or more and 10% by mass or less, more preferably 0% by mass or more and 5% by mass or less, and even more preferably 0% by mass or more and 2% by mass or less, based on the total mass of the polyisocyanate composition of the present embodiment.

[0143] <Coating composition> The coating composition of the present embodiment includes the above-described polyisocyanate composition. The coating composition preferably further includes a resin dispersed or emulsified in water.

[0144] The above-described polyisocyanate composition can be mixed with an organic solvent and optionally a resin and used as an organic solvent-based coating composition, but it is preferably mixed with a resin dispersed or emulsified in water and used as a coating composition.

[0145] By including the above-mentioned polyisocyanate composition, the coating composition of the present embodiment is excellent in gloss, water resistance, and salt water spray resistance when formed into a coating film.

[0146] Next, the details of each component included in the coating composition of the present embodiment will be described in detail below.

[0147] (Resin) In the above 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 (polyvalent active hydrogen compound) is preferred.

[0148] An active hydrogen compound is a compound in which two or more active hydrogens are bonded in the molecule. Examples of active hydrogen compounds include polyols, polyamines, polythiols, etc., but polyols are mostly used.

[0149] Specific examples of such active hydrogen compounds are not particularly limited, and include, for example, acrylic resins, polyester resins, polyether resins, epoxy resins, fluorine resins, polyurethane resins, polyvinylidene chloride copolymers, polyvinyl chloride copolymers, vinyl acetate copolymers, acrylonitrile-butadiene copolymers, polybutadiene copolymers, styrene-butadiene copolymers, etc.

[0150] Among them, as the active hydrogen compound, acrylic resins or polyester resins are preferred. For example, in terms of water resistance and salt water spray resistance, 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.

[0151] Also, in the coating composition of the present embodiment, these resins can be used in combination with resins such as melamine-based curing agents, urethane dispersions, and urethane acrylate emulsions, if necessary.

[0152] Further, these resins are preferably emulsified, dispersed or dissolved in water. Therefore, carboxy groups, sulfone groups, etc. contained in the resins can be neutralized.

[0153] The neutralizing agent for neutralizing carboxy groups, sulfone groups, etc. is not particularly limited, and examples thereof include ammonia, water-soluble amino compounds, etc.

[0154] 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.

[0155] Among them, the neutralizing agent is preferably a tertiary amine, more preferably triethylamine or dimethylethanolamine.

[0156] ≪Other Components≫ In addition to the polyisocyanate composition and resins described above, the coating composition of this embodiment may further contain additives generally added to paints. Examples of the additives include extender pigments, silane coupling agents, titanium coupling agents, organic phosphates, organic phosphites, thickeners, leveling agents, thixotropic agents, defoamers, freeze stabilizers, matting agents, crosslinking reaction catalysts (catalysts for promoting curing), anti-skinning agents, dispersants, wetting agents, fillers, plasticizers, lubricants, reducing agents, preservatives, fungicides, deodorants, anti-yellowing agents, ultraviolet absorbers, antistatic agents or charge control agents, anti-settling agents, surfactants, antioxidants, light stabilizers, polymerization inhibitors, etc. These additives may be contained alone or in combination of two or more.

[0157] ≪Method for Producing Coating Composition≫ The coating composition of this embodiment is obtained by mixing the above polyisocyanate composition and resins, and, if necessary, other components and the like using a known method.

[0158] For example, in the case of an aqueous-based coating composition, additives exemplified by the above other components are added to the resins or their aqueous dispersions or water-soluble substances as necessary. Next, the above polyisocyanate composition or its aqueous dispersion is added as a curing agent, and, if necessary, water or a solvent is further added to adjust the viscosity. Then, by forcibly stirring with a stirring device, an aqueous coating composition can be obtained.

[0159] When producing a solvent-based coating composition, first, additives exemplified by the above other components are added to the resins or their solvent dilutions as necessary. Next, the above polyisocyanate composition is added as a curing agent, and, if necessary, a solvent is further added to adjust the viscosity. Then, by stirring using manual stirring or a stirring device such as a magnetic stirrer, a solvent-based coating composition can be obtained.

[0160] <Coating substrate> The coating substrate of this embodiment is a coating substrate coated with the above coating composition. It is preferable that the coating substrate of this embodiment has a coating layer containing the above coating composition.

[0161] Since the coating substrate of this embodiment includes a coating film formed by curing the above coating composition, it is excellent in appearance and water resistance.

[0162] The coating substrate of this embodiment is obtained by applying the above coating composition onto a substrate using a known method such as roll coating, curtain flow coating, spray coating, bell coating, electrostatic coating, etc., and curing it through a normal temperature drying or baking process.

[0163] The coated substrate of this embodiment may include a desired substrate and, optionally, a normal primer before coating.

[0164] Examples of the substrate include metals, wood, glass, stone, ceramic materials, concrete, calcium silicate boards and gypsum boards, rigid and flexible plastics, fiber products, leather products, paper, and the like.

[0165] <Use applications> The polyisocyanate resin composition and coating composition of this embodiment can be used particularly in architectural paints, automotive paints, automotive repair paints, paints for construction machinery and agricultural machinery, paints for plastics, adhesives, binders, building materials, household water-based paints, other coating agents, sealing agents, inks, casting materials, elastomers, foams, plastic raw materials, and fiber treatment agents.

Examples

[0166] Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded.

[0167] The physical properties and evaluations of the polyisocyanate composition in the examples and comparative examples were measured as follows. Unless otherwise specified, "parts" and "%" mean "parts by mass" and "% by mass".

[0168] <Measurement method> [Physical property 1: Viscosity] The viscosity was measured at 25°C using an E-type viscometer (manufactured by Tokimec, Inc.). A standard rotor (1°34’×R24) was used. The rotation speeds are as follows.

[0169] (Rotation speed) 100 r.p.m. (when less than 128 mPa·s) 50 r.p.m. (when 128 mPa·s or more and less than 256 mPa·s) 20 r.p.m. (when 256 mPa·s or more and less than 640 mPa·s) 10 r.p.m. (when above 640 mPa·s and less than 1280 mPa·s) 5 r.p.m. (when above 1280 mPa·s and less than 2560 mPa·s) 2.5 r.p.m. (when above 2560 mPa·s and less than 5120 mPa·s)

[0170] [Physical Property 2: Isocyanate Group Content (NCO%)] Using the polyisocyanate compositions obtained in the examples and comparative examples as samples, the measurement of the isocyanate group content was carried out according to the method described in JIS K7301-1995 (Test Method for Toluene Diisocyanate Type Prepolymer for Thermosetting Urethane Elastomers). The following shows a more specific method for measuring the isocyanate group content (NCO%).

[0171] (1) Weigh 1 g (W g) of the sample into a 200 mL Erlenmeyer flask, add 20 mL of toluene to the flask, and dissolve the sample. (2) Then, add 20 mL of a 2.0 N di-n-butylamine·toluene solution to the above flask and let it stand for 15 minutes. (3) Add 70 mL of 2-propanol to the above flask, dissolve it to obtain a solution. (4) Titrate the solution obtained in (3) above with 1 mol / L hydrochloric acid to obtain the sample titration volume (V1 mL). (5) Even when no sample is added, perform the measurement in the same manner as in (1) to (3) above to obtain the blank titration volume (V0 mL). From the sample titration volume and blank titration volume obtained above, the isocyanate group content (NCO%) was calculated using the following formula (A).

[0172] Isocyanate group content (mass%) = (V0 - V1) × 42 / [W(1 g) × 1000] × 100 (A)

[0173] [Physical Property 3: Non-volatile Content] Using the polyisocyanate compositions obtained in the examples and comparative examples as samples, when 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), about 1 g of the sample was placed in it, and the mass of the cup before heating and drying (W1 g) was precisely weighed. Next, the cup containing the sample was heated in a dryer at 105 °C for 3 hours. Then, after cooling the cup after heating to room temperature, the mass of the cup was precisely weighed again (W2 g). Next, the mass percentage of the dry residue in the sample was taken as the nonvolatile content, and the nonvolatile content was calculated using the following formula (B). In the case without solvent dilution, the nonvolatile content was treated as being substantially 100%. Nonvolatile content (mass %) = (W2 - W0) / (W1 - W0) × 100 (B)

[0174] [Physical Property 4: Number average molecular weight of polyisocyanate composition and polyol component, mass fraction of uretdione dimer] The number average molecular weights of the polyisocyanate composition and the polyol were obtained by measuring the number average molecular weight based on polystyrene by GPC measurement under the measurement conditions shown below.

[0175] (Measurement conditions) Apparatus: Tosoh Corporation HLC - 8120GPC (trade name) Column: Tosoh Corporation TSKgel SuperH1000 (trade name) × 1 piece TSKgel SuperH2000 (trade name) × 1 piece TSKgel SuperH3000 (trade name) × 1 piece Carrier: Dimethylformamide Detection method: Differential refractometer

[0176] [Physical Property 5: Number average molecular weight of alcohol component] Using the alcohol as a sample, the number average molecular weight of the alcohol was determined by the following formula (3). The hydroxyl value of the alcohol was determined by the following (Physical Property 9). Number average molecular weight = 2 / (hydroxyl value of alcohol × 10 - 3 / 56.11) ···(3)

[0177] [Physical Property 6: Hydroxyl Value of Alcohol Component] Using alcohol as the sample, the hydroxyl value of the alcohol was determined according to JIS K 0070:1992. Specifically, 12.5 g of acetic anhydride was made up to 50 mL with pyridine to prepare an acetylation reagent. Next, 2.5 - 5.0 g of alcohol was accurately weighed into a 100 mL eggplant flask. 5 mL of the acetylation reagent and 10 mL of toluene were added to the eggplant flask with a whole pipette, and then a condenser was attached and heated with stirring at 100 °C for 1 hr. 2.5 mL of distilled water was added with a whole pipette, and heating and stirring were continued for another 10 min. After cooling for 2 - 3 minutes, 12.5 mL of ethanol was added, 2 - 3 drops of phenolphthalein were added as an indicator, and then titration was carried out with 0.5 mol / L alcoholic potassium hydroxide. On the other hand, as a blank test, 5 mL of the acetylation reagent, 10 mL of toluene, and 2.5 mL of distilled water were placed in a 100 mL eggplant flask, heated and stirred for 10 minutes, and then titration was carried out in the same manner. Based on this result, the hydroxyl value was calculated using the following formula (4). OH value (mg-KOH / g) = {(b - a) × 28.05 × f} / e ···(4) In formula (4), a represents the titration volume (mL) of the sample, b represents the titration volume (mL) of the blank test, e represents the sample mass (g), and f represents the factor of the titrant.

[0178] [Physical Property 7: Mass Ratio of Isocyanurate Trimer (A) and Polyisocyanate Compound (B) Bonded to Anionic Compound via Allophanate Group] Using a polyisocyanate composition as a sample, the mass ratio of the isocyanurate trimer (A) to the polyisocyanate compound (B) bonded to an anionic compound via allophanate groups was determined from the peak area ratio based on measurements of LC-MS and UV-MS using "UPLC" from WATERS. It was calculated from the area of each peak. The area of the polyisocyanate compound (B) was calculated from the sum of the allophanate reaction product of 1 molecule of anionic compound and 2 molecules of cyclic trimer and the allophanate reaction product of 1 molecule of anionic compound, 1 molecule of cyclic trimer, and 1 molecule of cyclic pentamer. The retention times were as follows: allophanate reaction product of 1 molecule of anionic compound and 2 molecules of cyclic trimer: 6.06 min, allophanate reaction product of 1 molecule of anionic compound, 1 molecule of cyclic trimer, and 1 molecule of cyclic pentamer: 6.80 min, cyclic trimer: 5.58 min. LC device: manufactured by WATERS, UPLC (trade name) Column: manufactured by WATERS, ACQUITY UPLC BEH T3 1.7μm C18 inner diameter 2.1mm × 50mm Flow rate: 0.3 mL / min Mobile phase: A = water (0.1% HCOOH), B = acetonitrile (0.1% HCOOH) Gradient condition: The initial mobile phase composition was A / B = 98 / 2. After sample injection, the ratio of B was linearly increased to A / B = 0 / 100 after 10 minutes. MS device: manufactured by WATERS, Synapt G2 Ionization: ESI+, ESI-

[0179] [Adjustment Example 1: Production of Coating Composition] Propylene glycol monomethyl ether diacetate was added to the polyisocyanate compositions obtained in the examples and comparative examples, and dissolved to a solid content of 70% by mass to prepare a solution of the polyisocyanate composition. Next, 60 g of an acrylic polyol aqueous dispersion (product name: Bayhydrol A2470, hydroxyl group amount per resin: 3.9% by mass, solid content: 45% by mass, manufactured by Covestro) and 20 g of deionized water were weighed into a container, and stirred at 600 rpm for 5 minutes using a propeller blade to prepare an acrylic polyol diluted product. Each polyisocyanate solution was added at a ratio such that the ratio (NCO / OH) of the molar amount of isocyanate groups in the polyisocyanate composition obtained in the examples and comparative examples to the molar amount of hydroxyl groups in this diluted product was 1.5. Further, deionized water was added and adjusted so that the viscosity became 20 seconds with a Ford cup (No. 4), and stirred at 600 rpm for 10 minutes using a propeller blade to obtain each coating composition. Using the prepared coating composition, the following evaluations were performed.

[0180] <Evaluation method> [Evaluation 1: Colority] The colority of the polyisocyanate compositions obtained in the examples and comparative examples was measured as the Hazen color number (APHA) using a colorimeter PFXi-195 manufactured by Lovibond. The colority was evaluated according to the evaluation criteria shown below.

[0181] (Evaluation criteria) ◎: 30 or less ○: 30 or more and 45 or less △: 45 or more and 60 or less ×: 60 or more

[0182] [Evaluation 2: Evaluation of turbidity during storage after solvent dilution] The polyisocyanate compositions obtained in the examples and comparative examples were diluted with propylene glycol monomethyl ether acetate having a water content of 1000 ppm to a solid content of 60%, and after storage at 50°C for 2 weeks, the transmittance at a wavelength of 430 nm with an optical path length of 2 cm was measured using a spectrophotometer UVmini-1240 manufactured by Shimadzu Corporation. (Evaluation criteria) ◎: Transmittance is 90% or more 〇: Transmittance is 80% or more and less than 90% △: Transmittance is 70% or more and less than 80% ×: Transmittance is less than 70%

[0183] [Evaluation 3: Dispersion] The dispersion was evaluated using the coating composition manufactured in Preparation Example 1. (1) The mass of a 100 mL flask and Yoshino paper was measured (W0 g). (2) 20.0 g of the coating composition was taken in a 100 mL flask and filtered with 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 determined (W1 g). (Evaluation criteria) ◎: Less than 0.2 g 〇: 0.2 g or more and less than 1.0 g △: 1.0 g or more, with lumps

[0184] [Evaluation 4: Coating film gloss] On a horizontal table, the water-based two-component paint composition manufactured in Preparation Example 1 was applied to the pretreated steel plate with an air spray gun (spray pressure: 0.3 MPa, spray nozzle: 1.8 mm) so that the dry film thickness was 50 ± 5 μm, and dried in an atmosphere of 23°C / 50% RH for 7 days to obtain a coating film. Then, using a gloss meter (BYK micro-TRI-gloss), the 60-degree gloss value was measured according to GB-T6753.1-2007. The gloss of the coating film was evaluated according to the following evaluation criteria. Evaluated.

[0185] (Evaluation criteria) ◎: 60-degree gloss value is 90% or more ○: 60-degree gloss value is 85% or more and less than 90% △: 60-degree gloss value is less than 85%

[0186] [Evaluation 5: Alkali resistance] Using the same method as in the above "Evaluation 4", a coating film was obtained by curing each aqueous two-component paint composition. The coating film was obtained by drying for 7 days in an atmosphere of 23°C / 50%RH. A steel plate with a coating film (hereinafter sometimes referred to as a "coated plate") was immersed in 5% sodium hydroxide water at 23°C for 24 hours, and the state of the coating film after removing the liquid remaining on the surface was observed. The alkali resistance of the coating film was evaluated according to the following evaluation criteria.

[0187] (Evaluation Criteria) ◎: Swelling and blistering occur in 3 days or more ○: Swelling and blistering occur in 2 days or more and less than 3 days △: Swelling and blistering occur in less than 2 days

[0188] (Synthesis of Sulfonic Acid Amine) [Synthesis Example 1] (Synthesis of HES / TPA) 10 parts by mass of 1-propanol was added to 20 parts by mass of a 70% by mass aqueous solution of 2-hydroxyethanesulfonic acid (hereinafter sometimes abbreviated as "HES") and stirred to obtain a solution. Further, tripropylamine (hereinafter sometimes abbreviated as "TPA") was weighed in a molar equivalent ratio to HES of 1, and a solution diluted with the same mass part of 1-propanol was added dropwise to the above solution while stirring. Stirring was stopped 1 hour after the start of dropping, and dehydration and desolvation were carried out with an evaporator to obtain tripropylamine 2-hydroxyethanesulfonate (hereinafter sometimes abbreviated as "HES / TPA") with a solid content of 99.8% by mass.

[0189] [Synthesis Example 2] (Synthesis of HES / TBA) To an aqueous solution of 2-hydroxyethanesulfonic acid (hereinafter sometimes abbreviated as "HES") at 70% by mass of 20 parts by mass, 10 parts by mass of 1-propanol was added and stirred to obtain a solution. Further, tributylamine (hereinafter sometimes abbreviated as "TBA") was weighed out at a molar equivalent ratio to HES of 1, and a solution diluted with the same mass part of 1-propanol was added dropwise to the above solution during stirring. Stirring was stopped 1 hour after the start of the dropwise addition, and dehydration and desolvation were carried out with an evaporator to obtain tributylamine 2-hydroxyethanesulfonate (hereinafter sometimes abbreviated as "HES / TBA") with a solid content of 99.8% by mass.

[0190] [Synthesis Example 3] (Production of Polyisocyanate P1) A 2L separable flask equipped with a stirrer, a thermometer, and an Aldershock with a vacuum jacket having a reflux head at the top was placed in a nitrogen atmosphere, 1,000 parts by mass of HDI was charged, and the temperature inside the reactor was maintained at 70°C for 2 hours while stirring. Thereto, 1.0 part by mass of a solution obtained by diluting tetramethylammonium caprylate with isobutanol to 5% by mass as an isocyanuration catalyst was added, and an isocyanuration reaction was carried out. When the yield reached 25% by mass, phosphoric acid was added to stop the reaction. The reaction solution was heated at 100°C for 1 hour, cooled, filtered, and unreacted HDI was removed using a thin-film evaporator to obtain polyisocyanate P1. The viscosity of the obtained polyisocyanate P1 at 25°C was 1,300 mPa·s, and the NCO content was 23.0% by mass.

[0191] [Synthesis Example 4] (Production of Polyisocyanate P2) The inside of the same apparatus as in Synthesis Example 3 was made into a nitrogen atmosphere, 1,000 parts by mass of HDI and 3.1 parts by mass of 2-ethylhexanol were charged, and while stirring, the temperature inside the reactor was maintained at 70 °C for 2 hours. Then, tetramethylammonium caprylate, which is an isocyanuration reaction catalyst, was added, and when the yield reached 40% by mass, phosphoric acid was added to stop the reaction. The reaction solution was heated at 100 °C for 1 hour, cooled, filtered, and unreacted HDI was removed using a thin-film evaporator to obtain polyisocyanate P2. The viscosity of the obtained polyisocyanate P2 at 25 °C was 2,600 mPa·s, and the NCO content was 21.7% by mass.

[0192] [Synthesis Example 5] (Production of Polyisocyanate P3) The inside of the same apparatus as in Synthesis Example 3 was made into a nitrogen atmosphere, 1,000 parts by mass of HDI and 1.5 parts by mass of 2-ethylhexanol were charged, and while stirring, a urethanization reaction was carried out at 90 °C for 1 hour. Then, 1.0 part by mass of a solution in which tetramethylammonium caprylate as an allophanatization and isocyanuration catalyst was diluted to 5% by mass with isobutanol was added, and an allophanatization and isocyanuration reaction was carried out. When the increase in the refractive index of the reaction solution reached 0.012, phosphoric acid was added to stop the reaction. The reaction solution was heated at 160 °C for 1 hour, cooled, filtered, and unreacted HDI was removed using a thin-film evaporator to obtain polyisocyanate P3. The obtained polyisocyanate P3 had a viscosity of 470 mPa·s at 25 °C and an NCO content of 23.2% by mass.

[0193] [Synthesis Example 6] (Production of Polyisocyanate P4) The inside of the same apparatus as in Synthesis Example 3 was made into a nitrogen atmosphere, 99.6 parts by mass of polyisocyanate P1 obtained in Synthesis Example 3 and 0.4 part by mass of 1,3-butanediol were charged, and while stirring, a urethanization reaction was carried out at 90 °C for 1 hour. Then, while stirring, a urethanization reaction was further carried out at 110 °C for 2 hours to obtain polyisocyanate P4. The obtained polyisocyanate P4 had a viscosity of 1800 mPa·s at 25 °C and an NCO content of 22.5% by mass.

[0194] [Synthesis Example 7] (Production of Polyisocyanate P5) The inside of the same apparatus as in Synthesis Example 3 was made into a nitrogen atmosphere, 98.0 parts by mass of polyisocyanate P1 obtained in Synthesis Example 3 and 2.0 parts by mass of 1,2-propanediol were charged, and a urethanization reaction was carried out at 90 °C for 1 hour with stirring. Then, a urethanization reaction was further carried out at 110 °C for 2 hours with stirring to obtain polyisocyanate P5. The obtained polyisocyanate P5 had a viscosity of 3600 mPa·s at 25 °C and an NCO content of 20.8% by mass.

[0195] [Synthesis Example 8] (Production of Polyisocyanate P6) The inside of the same apparatus as in Synthesis Example 3 was made into a nitrogen atmosphere, 96.0 parts by mass of polyisocyanate P3 obtained in Synthesis Example 5 and 4.0 parts by mass of 1,3-propanediol were charged, and a urethanization reaction was carried out at 90 °C for 1 hour with stirring. Then, a urethanization reaction was further carried out at 110 °C for 2 hours with stirring to obtain polyisocyanate P6. The obtained polyisocyanate P6 had a viscosity of 4400 mPa·s at 25 °C and an NCO content of 19.5% by mass.

[0196] [Synthesis Example 9] (Production of Polyisocyanate P7) The inside of the same apparatus as in Synthesis Example 3 was made into a nitrogen atmosphere, 96.0 parts by mass of polyisocyanate P3 obtained in Synthesis Example 5 and 4.0 parts by mass of polytetramethylene glycol "PTMG-650" (manufactured by Mitsubishi Chemical Corporation, number average molecular weight 650) were charged, and a urethanization reaction was carried out at 90 °C for 1 hour with stirring. Then, a urethanization reaction was further carried out at 110 °C for 2 hours with stirring to obtain polyisocyanate P7. The obtained polyisocyanate P7 had a viscosity of 2600 mPa·s at 25 °C and an NCO content of 21.6% by mass.

[0197] [Example 1] (Production and Evaluation of Polyisocyanate Composition PA-1) The inside of the same apparatus as in Synthesis Example 3 was made into a nitrogen atmosphere, 96.0 g of polyisocyanate P1 obtained in Synthesis Example 3 and 4.0 g of tripropylamine salt of 2-hydroxyethanesulfonic acid (HES / TPA) obtained in Synthesis Example 1 were added, and the mixture was stirred at 105 °C for 5 hours to carry out the reaction, and a polyisocyanate composition PA-1 was obtained. The physical properties and evaluation results of the obtained polyisocyanate composition PA-1 are shown in Table 1.

[0198] [Example 2] (Production and evaluation of polyisocyanate composition PA-2) A polyisocyanate composition PA-2 was obtained in the same manner as in Example 1, except that 96.0 g of polyisocyanate P2 was used and the mixture was stirred at 110 °C for 5 hours to cause a reaction. The physical properties and evaluation results of the obtained polyisocyanate composition PA-2 are shown in Table 1.

[0199] [Example 3] (Production and evaluation of polyisocyanate composition PA-3) A polyisocyanate composition PA-3 was obtained in the same manner as in Example 1, except that the mixture was stirred at 120 °C for 5 hours to cause a reaction. The physical properties and evaluation results of the obtained polyisocyanate composition PA-3 are shown in Table 1.

[0200] [Example 4] (Production and evaluation of polyisocyanate composition PA-4) A polyisocyanate composition PA-4 was obtained in the same manner as in Example 1, except that the mixture was stirred at 125 °C for 5 hours to cause a reaction. The physical properties and evaluation results of the obtained polyisocyanate composition PA-4 are shown in Table 1.

[0201] [Example 5] (Production and evaluation of polyisocyanate composition PA-5) The inside of the same apparatus as in Synthesis Example 3 was made into a nitrogen atmosphere, 90.0 g of polyisocyanate P1 obtained in Synthesis Example 3 and 10.0 g of tripropylamine salt of 2-hydroxyethanesulfonic acid (HES / TPA) obtained in Synthesis Example 1 were added, and the mixture was stirred at 105 °C for 5 hours to carry out the reaction, and a polyisocyanate composition PA-5 was obtained. The physical properties and evaluation results of the obtained polyisocyanate composition PA-5 are shown in Table 1.

[0202] [Example 6] (Production and Evaluation of Polyisocyanate Composition PA-6) The inside of the same apparatus as in Synthesis Example 3 was made into a nitrogen atmosphere, 98.0 g of polyisocyanate P1 obtained in Synthesis Example 3 and 2.0 g of tripropylamine salt of 2-hydroxyethanesulfonic acid (HES / TPA) obtained in Synthesis Example 1 were added, and the mixture was stirred at 105 °C for 5 hours to carry out the reaction, and a polyisocyanate composition PA-6 was obtained. The physical properties and evaluation results of the obtained polyisocyanate composition PA-6 are shown in Table 1.

[0203] [Example 7] (Production and Evaluation of Polyisocyanate Composition PA-7) The inside of the same apparatus as in Synthesis Example 3 was made into a nitrogen atmosphere, 98.0 g of polyisocyanate P3 obtained in Synthesis Example 5 and 2.0 g of tripropylamine salt of 2-hydroxyethanesulfonic acid (HES / TPA) obtained in Synthesis Example 1 were added, and the mixture was stirred at 110 °C for 5 hours to carry out the reaction, and a polyisocyanate composition PA-7 was obtained. The physical properties and evaluation results of the obtained polyisocyanate composition PA-7 are shown in Table 1.

[0204] [Example 8] (Production and Evaluation of Polyisocyanate Composition PA-8) The inside of the same apparatus as in Synthesis Example 3 was made into a nitrogen atmosphere, 96.0 g of polyisocyanate P4 obtained in Synthesis Example 6 and 4.0 g of tripropylamine salt of 2-hydroxyethanesulfonic acid (HES / TPA) obtained in Synthesis Example 1 were added, and the mixture was stirred at 105 °C for 5 hours to carry out the reaction, and a polyisocyanate composition PA-8 was obtained. The physical properties and evaluation results of the obtained polyisocyanate composition PA-8 are shown in Table 1.

[0205] [Example 9] (Production and Evaluation of Polyisocyanate Composition PA-9) The inside of the same apparatus as in Synthesis Example 3 was made into a nitrogen atmosphere, 97.0 g of polyisocyanate P5 obtained in Synthesis Example 7 and 3.0 g of tripropylamine salt of 2-hydroxyethanesulfonic acid (HES / TPA) obtained in Synthesis Example 1 were added, and the mixture was stirred at 105 °C for 5 hours to carry out the reaction, and polyisocyanate composition PA-9 was obtained. The physical properties and evaluation results of the obtained polyisocyanate composition PA-9 are shown in Table 2.

[0206] [Example 10] (Production and Evaluation of Polyisocyanate Composition PA-10) The inside of the same apparatus as in Synthesis Example 3 was made into a nitrogen atmosphere, 96.0 g of polyisocyanate P6 obtained in Synthesis Example 8 and 4.0 g of tributylamine salt of 2-hydroxyethanesulfonic acid (HES / TBA) obtained in Synthesis Example 2 were added, and the mixture was stirred at 105 °C for 5 hours to carry out the reaction, and polyisocyanate composition PA-10 was obtained. The physical properties and evaluation results of the obtained polyisocyanate composition PA-10 are shown in Table 2.

[0207] [Example 11] (Production and Evaluation of Polyisocyanate Composition PA-11) The inside of the same apparatus as in Synthesis Example 3 was made into a nitrogen atmosphere, 96.0 g of polyisocyanate P7 obtained in Synthesis Example 9 and 4.0 g of tripropylamine salt of 2-hydroxyethanesulfonic acid (HES / TPA) obtained in Synthesis Example 2 were added, and the mixture was stirred at 105 °C for 5 hours to carry out the reaction, and polyisocyanate composition PA-11 was obtained. The physical properties and evaluation results of the obtained polyisocyanate composition PA-11 are shown in Table 2.

[0208] [Example 12] (Production and Evaluation of Polyisocyanate Composition PA-12) The inside of the same apparatus as in Synthesis Example 3 was made into a nitrogen atmosphere, and 2.5 g of 3-cyclohexylaminopropanesulfonic acid (CAPS) and 1.5 g of N,N-dimethylcyclohexylamine (DMCHA) were added to 96.0 g of the polyisocyanate P1 obtained in Synthesis Example 3, followed by stirring at 90 °C for 5 hours to conduct a reaction, thereby obtaining a polyisocyanate composition PA-12. The physical properties and evaluation results of the obtained polyisocyanate composition PA-12 are shown in Table 2.

[0209] [Example 13] (Production and Evaluation of Polyisocyanate Composition PA-13) The inside of the same apparatus as in Synthesis Example 3 was made into a nitrogen atmosphere, and 2.6 g of 3-cyclohexylaminobutanesulfonic acid (CABS) and 1.4 g of N,N-dimethylcyclohexylamine (DMCHA) were added to 96.0 g of the polyisocyanate P1 obtained in Synthesis Example 3, followed by stirring at 110 °C for 5 hours to conduct a reaction, thereby obtaining a polyisocyanate composition PA-13. The physical properties and evaluation results of the obtained polyisocyanate composition PA-13 are shown in Table 2.

[0210] [Example 14] (Production and Evaluation of Polyisocyanate Composition PA-14) The inside of the same apparatus as in Synthesis Example 3 was made into a nitrogen atmosphere, 4.0 g of tripropylamine salt of 2-hydroxyethanesulfonic acid (HES / TPA) obtained in Synthesis Example 1 was added to 56.0 g of the polyisocyanate P1 obtained in Synthesis Example 3, and after stirring at 100 °C for 5 hours to conduct a reaction, 40.0 g of the polyisocyanate P1 obtained in Synthesis Example 3 was added, followed by stirring at 60 °C for 1 hour to obtain a polyisocyanate composition PA-14. The physical properties and evaluation results of the obtained polyisocyanate composition PA-14 are shown in Table 2.

[0211] [Comparative Example 1] (Production and Evaluation of Polyisocyanate Composition PB-1) The inside of the same apparatus as in Synthesis Example 3 was made into a nitrogen atmosphere, 96.0 g of polyisocyanate P1 obtained in Synthesis Example 3 and 4.0 g of tributylamine salt of 2-hydroxyethanesulfonic acid (HES / TPA) obtained in Synthesis Example 1 were added, and the mixture was stirred at 130 °C for 5 hours to conduct a reaction, thereby obtaining a polyisocyanate composition PB-1. Table 2 shows the physical properties and evaluation results of the obtained polyisocyanate composition PB-1.

[0212] [Comparative Example 2] (Production and Evaluation of Polyisocyanate Composition PB-2) The inside of the same apparatus as in Synthesis Example 3 was made into a nitrogen atmosphere, 96.0 g of polyisocyanate P-3 obtained in Synthesis Example 5 and 4.0 g of tributylamine salt of 2-hydroxyethanesulfonic acid (HES / TPA) obtained in Synthesis Example 1 were added, and the mixture was stirred at 130 °C for 5 hours to conduct a reaction, thereby obtaining a polyisocyanate composition PB-2. Table 2 shows the physical properties and evaluation results of the obtained polyisocyanate composition PB-2.

[0213]

Table 1

[0214]

Table 2

Industrial Applicability

[0215] According to the polyisocyanate composition of the present embodiment, a polyisocyanate composition is provided which has good chromaticity, reduced turbidity during storage after dilution with a hydrophilic solvent, excellent dispersibility when blended with a main agent, and excellent gloss and alkali resistance when formed into a coating film. Further, an aqueous coating composition and a coated substrate using the polyisocyanate composition can be provided.

Claims

1. A polyisocyanate composition comprising a hydrophilic polyisocyanate compound, The hydrophilic polyisocyanate compound is a reaction product of a polyisocyanate and an anionic compound having a sulfonic acid group, The polyisocyanate is derived from one or more diisocyanates selected from the group consisting of aliphatic diisocyanates, alicyclic diisocyanates, and aromatic diisocyanates, The hydrophilic polyisocyanate compound includes an isocyanurate trimer (A) and a polyisocyanate compound (B) bonded to the anionic compound via an allophanate group, A polyisocyanate composition, wherein the mass ratio [(B) / (A)] of the polyisocyanate compound (B) to the isocyanurate trimer (A) is 50 / 10,000 or less.

2. The polyisocyanate composition of claim 1 , wherein the polyisocyanate comprises a reaction product with an alcohol.

3. The polyisocyanate composition according to claim 2 , wherein the alcohol has an average number of 2.0 to 3.5 hydroxyl groups per molecule and a number average molecular weight of 450 or less.

4. The polyisocyanate composition according to claim 2 or 3, wherein the mass fraction of the alcohol in the polyisocyanate composition is 4.5% or less.

5. 3. The polyisocyanate composition according to claim 1, wherein the anionic compound 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.

6. 3. The polyisocyanate composition according to claim 1, wherein the sulfonic acid group of the anionic compound is neutralized with an inorganic base or an organic amine compound.

7. The polyisocyanate composition according to claim 1 or 2, wherein the anionic compound is a compound represented by the following general formula (1): 【Chemistry 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 include 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.

8. The polyisocyanate composition according to claim 1 or 2, wherein the anionic compound is a compound represented by the following general formula (2): 【Chemistry 2】 (In general formula (2), R ２１ and R ２２ are each independently a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms which may contain a hydroxyl group. ２２ and R ２３ At least one of R is a hydrogen atom. ２３ is a hydrocarbon group having 1 to 12 carbon atoms which may contain a hydroxyl group.

9. A coating composition comprising the polyisocyanate composition according to claim 1 or 2.

10. A coated substrate coated with the coating composition according to claim 9.

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