JP2024162147A - Formulation composition, coating composition, and coating film - Google Patents

Abstract

To provide a compounded composition excellent in mutual solubility and curability with a main agent, a high cross-linking density and anti-blocking properties of a cured coating film, and solvent resistance, and to provide a coating composition and a coating film.SOLUTION: A compounded composition contains block polyisocyanate component and polyol. The compounded composition is such that: the block polyisocyanate component is a reactant with diisocyanate, one or more kinds of alcohol and a heat dissociable block agent; the block polyisocyanate component has a molar ratio of [isocyanurate/(isocyanurate group+ allophanate group)] of 0.1 or more and 0.9 or less; a mass fraction of block isocyanate with a number average molecular weight of 1,000 or less is 5.0 mass% or more and 50.0 mass% or less; and in the block polyisocyanate component, a molar ratio (NCO/OH) of an isocyanate group bonded with the heat dissociable block agent to a hydroxy group in the polyol is 0.05/1.0 or more and 1.2/1.0 or less.SELECTED DRAWING: None

Description

The present invention relates to a formulation composition, a coating composition, and a coating film.

Coating films obtained from two-component polyurethane compositions using a polyisocyanate composition derived from an aliphatic diisocyanate or alicyclic diisocyanate as a curing agent exhibit excellent performance in terms of weather resistance, chemical resistance, abrasion resistance, etc., and are therefore widely used as paints, inks, adhesives, etc. In recent years, with growing awareness of global environmental issues, two-component polyurethane compositions that do not use organic solvents or use reduced amounts of organic solvents have been proposed.

In addition, from the viewpoint of easy handling, one-component paints are desired whose paint properties do not change even when the base agent and the curing agent are mixed. These are made by protecting the isocyanate group of the curing agent with a blocking agent, and by heating after painting on site, the isocyanate group is regenerated and reacts with the hydroxyl group of the base polyol to form a hardened coating film. Such isocyanates are called blocked polyisocyanates. Many blocking agents have been studied, and representative examples include phenol and methyl ethyl ketoxime.
However, the curing temperature is high, and the high baking temperature not only consumes a lot of energy, but also limits the application to materials that are not heat resistant.

Several proposals have been made to lower the curing temperature of blocked polyisocyanates.
Low-temperature curing properties have been achieved by using a pyrazole-based compound as a blocking agent (Patent Document 1). Also, a technique has been proposed for increasing the number of isocyanate functional groups to improve the low-temperature curing properties of blocked polyisocyanates (Patent Document 2).

European Patent Publication No. 0159117 Japanese Patent Application Publication No. 9-255915

However, paint compositions prepared by blending the blocked polyisocyanates described in Patent Documents 1 and 2 as a curing agent may have poor compatibility with some base agents, resulting in poor appearance of the coating film formed. In particular, when combined with a base agent containing fluorine, separation from the curing agent and clouding may occur, the appearance of the applied and baked coating film may be poor, and drying after baking may be insufficient.
The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a blended composition, a coating composition, and a coating film that are capable of producing a cured film that has excellent compatibility with a base agent and curability, and has high crosslink density, blocking resistance, and solvent resistance.

That is, the present invention includes the following aspects.
[1] A blended composition containing a blocked polyisocyanate component and a polyol, wherein the blocked polyisocyanate component is a reaction product of a diisocyanate, one or more alcohols, and a thermally dissociable blocking agent, the diisocyanate is one or more diisocyanates selected from aliphatic diisocyanates and alicyclic diisocyanates, the blocked polyisocyanate component has a molar ratio of [isocyanurate/(isocyanurate group+allophanate group)] of 0.1 to 0.9, and the mass fraction of blocked isocyanates having a number average molecular weight of 1,000 or less contained in the blocked polyisocyanate component is 5.0% by mass to 50.0% by mass, and the blocked polyisocyanate component has a molar ratio (NCO/OH) of an isocyanate group bonded to the thermally dissociable blocking agent to a hydroxyl group in the polyol of 0.05/1.0 to 1.2/1.0.
[2] The blended composition according to [1], wherein the alcohol has a number of hydroxyl groups of 1.5 or more and 6.0 or less and a number average molecular weight of 70 or more and 1,000 or less.
[3] The blended composition according to [1] or [2], wherein the number average molecular weight of the blocked polyisocyanate component is 900 or more and 3,000 or less.
[4] The blended composition according to any one of [1] to [3], wherein the average number of isocyanate groups bonded to the thermally dissociable blocking agent per molecule is 2.8 to 6.2.
[5] The blended composition according to any one of [1] to [4], wherein the molar ratio of urethane groups to isocyanurate groups in the blocked polyisocyanate component is 0.3 or less.
[6] The blended composition according to any one of [1] to [5], wherein the thermally dissociable blocking agent is at least one selected from the group consisting of oxime compounds, acid amide compounds, amine compounds, active methylene compounds, and pyrazole compounds.
[7] The blended composition according to any one of [1] to [6], wherein the thermally dissociable blocking agent is a pyrazole compound.
[8] The polyol contains a fluorine polyol, the fluorine content of the fluorine polyol is 2.0 mass% or more and 50.0 mass% or less, and the hydroxyl value in the fluorine polyol is 30 mg KOH / g or more and 200 mg KOH / g or less. The blended composition according to any one of [1] to [7].
[9] The blended composition according to any one of [1] to [8], wherein the polyol contains 10% by mass or more of a fluorine polyol.
[10] A coating composition comprising the blend composition according to any one of [1] to [9].
[11] A coating film obtained by curing the coating composition according to [10].

The present invention provides a compounding composition, a coating composition, and a coating film that can produce a cured film that has excellent compatibility and curability, high crosslink density, blocking resistance, and solvent resistance.

<Composition>
The blended composition of the present embodiment contains a blocked polyisocyanate component and a polyol. Both components are described in detail below.

<Blocked polyisocyanate component>
The blocked polyisocyanate component used in the present embodiment is a reaction product of a diisocyanate, one or more alcohols, and a thermally dissociable blocking agent.
More specifically, the blocked polyisocyanate component contained in the blend composition of the present embodiment is obtained from one or more diisocyanates selected from aliphatic diisocyanates and alicyclic diisocyanates, one or more alcohols, and a thermally dissociable blocking agent.

(Diisocyanate)
Examples of the diisocyanate as a raw material for the blocked polyisocyanate component include aliphatic diisocyanates and alicyclic diisocyanates.

Aliphatic diisocyanates are not particularly limited, but examples include 1,4-diisocyanatobutane, 1,5-diisocyanatopentane, ethyl (2,6-diisocyanato)hexanoate, 1,6-diisocyanatohexane (hereinafter sometimes referred to as "HDI"), 1,9-diisocyanatononane, 1,12-diisocyanatododecane, 2,2,4- or 2,4,4-trimethyl-1,6-diisocyanatohexane, etc.

Alicyclic diisocyanates are not particularly limited, but examples include 1,3- or 1,4-bis(isocyanatomethyl)cyclohexane (hereinafter sometimes referred to as "hydrogenated XDI"), 1,3- or 1,4-diisocyanatocyclohexane, 3,5,5-trimethyl-1-isocyanato-3-(isocyanatomethyl)cyclohexane (hereinafter sometimes referred to as "IPDI"), 4-4'-diisocyanato-dicyclohexylmethane (hereinafter sometimes referred to as "hydrogenated MDI"), 2,5- or 2,6-diisocyanatomethylnorbornane, etc.

Among them, from the viewpoint of weather resistance, HDI, IPDI, hydrogenated XDI, or hydrogenated MDI is preferred as the diisocyanate, and HDI or IPDI is more preferred.

These diisocyanates can be used alone or in combination of two or more.

In addition to the diisocyanates, aliphatic triisocyanates may be included. Examples of aliphatic triisocyanates include 1,3,6-triisocyanatohexane, 1,8-diisocyanato-4-isocyanatomethyloctane, and 2-isocyanatoethyl-2,6-diisocyanato-hexanoate.

(alcohol)
The alcohol as a raw material of the blocked polyisocyanate component preferably has a hydroxyl group number of 1.5 or more and 6.0 or less. From the viewpoint of obtaining a coating film excellent in curability and crosslink density, the number of hydroxyl groups of the alcohol is more preferably 1.8 or more, and even more preferably 2.0 or more. Moreover, from the viewpoint of obtaining a coating film excellent in compatibility with the base agent and solvent resistance, the number of hydroxyl groups of the alcohol is more preferably 5.0 or less, and even more preferably 4.0 or less.

Furthermore, the number average molecular weight of the alcohol is preferably 70 or more and 1,000 or less. From the viewpoint of obtaining a coating film excellent in curability and blocking resistance, the number average molecular weight of the alcohol is more preferably 80 or more. Moreover, from the viewpoint of improving compatibility with the base agent, the number average molecular weight of the alcohol is more preferably 900 or less, and even more preferably 800 or less.
The number average molecular weight can be measured, for example, by using gel permeation chromatography (GPC).

Examples of alcohols that satisfy the above-mentioned number of hydroxyl groups and 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, and 2,5-hexanediol. Examples of triols include glycerin and trimethylolpropane, and examples of tetraols include pentaerythritol. Examples of triols include glycerin and trimethylolpropane, and examples of tetraols include pentaerythritol.

Polymerized alcohols include polyester polyols, polyether polyols, acrylic polyols, polyolefin polyols, polycarbonate diols, etc.

Examples of polyester polyols include polyester polyols obtained by a condensation reaction of a dibasic acid selected from the group of carboxylic acids such as succinic acid, adipic acid, sebacic acid, dimer acid, maleic anhydride, phthalic anhydride, isophthalic acid, and terephthalic acid, alone or in mixture, with a polyhydric alcohol selected from the group of ethylene glycol, propylene glycol, diethylene glycol, neopentyl glycol, trimethylolpropane, and glycerin, alone or in mixture, and polycaprolactones obtained by ring-opening polymerization of ε-caprolactone with a polyhydric alcohol, for example.

Examples of polyether polyols include polyether polyols obtained by randomly or block-adding alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, cyclohexene oxide, and styrene oxide to polyhydric hydroxy compounds or mixtures thereof using strong basic catalysts such as hydroxides of lithium, sodium, and potassium, alcoholates, and alkylamines, and composite metal cyanide complexes such as metal porphyrin and zinc hexacyanocobaltate complexes, polyether polyols obtained by reacting alkylene oxides with polyamine compounds such as ethylenediamines, and so-called polymer polyols obtained by polymerizing acrylamide and the like using these polyethers as a medium.

Polycarbonate diols have repeating structural units formed by dehydration condensation of two alcohol groups and one carbonate group. Examples of polycarbonate diols include those obtained by copolymerizing a first diol having 2 to 20 carbon atoms, a second diol having 2 to 20 carbon atoms (hereinafter simply referred to as "two types of diols"), and a carbonate compound.

These alcohols may be used alone or in combination.

In this embodiment, the mass fraction of the alcohol in the blocked polyisocyanate component is preferably 0.01% by mass or more and 20.0% by mass or less. From the viewpoint of simultaneously achieving compatibility with the base agent and obtaining a coating film that is excellent in curability, crosslink density, blocking resistance, and solvent resistance, the mass fraction of the alcohol in the blocked polyisocyanate component is more preferably 0.02% by mass or more and 15.0% by mass or less.

(Thermal dissociation blocking agent)
In the blocked polyisocyanate component, at least a part of the isocyanate group is blocked by a thermally dissociable blocking agent. The thermally dissociable blocking agent is a compound having one active hydrogen in the molecule, and has the property of dissociating from the isocyanate group by heating. Specific examples of the thermally dissociable blocking agent include alcohol-based compounds, alkylphenol-based compounds, phenol-based compounds, active methylene-based compounds, mercaptan-based compounds, acid amide-based compounds, acid imide-based compounds, imidazole-based compounds, urea-based compounds, oxime-based compounds, amine-based compounds, imine-based compounds, and pyrazole-based compounds.

Specific examples of thermally dissociable blocking agents include the compounds shown in (1) to (13) below. These blocking agents may be used alone or in combination of two or more.

(1) Alcohol compounds: methanol, ethanol, 2-propanol, n-butanol, sec-butanol, 2-ethyl-1-hexanol, 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol.

(2) Alkylphenol compounds: mono- or di-alkylphenols having an alkyl group having 4 or more carbon atoms as a substituent. For example, mono-alkylphenols such as n-propylphenol, i-propylphenol, n-butylphenol, sec-butylphenol, t-butylphenol, n-hexylphenol, 2-ethylhexylphenol, n-octylphenol, and n-nonylphenol; di-n-propylphenol, diisopropylphenol, isopropyl cresol, di-n-butylphenol, di-t-butylphenol, di-sec-butylphenol, di-n-octylphenol, di-2-ethylhexylphenol, and di-n-nonylphenol.

(3) Phenolic compounds: phenol, cresol, ethylphenol, styrenated phenol, hydroxybenzoic acid esters.

(4) Active methylene compounds: dimethyl malonate, diethyl malonate, methyl acetoacetate, ethyl acetoacetate, acetylacetone.

(5) Mercaptan compounds: butyl mercaptan, dodecyl mercaptan.
(6) Acid amide compounds: acetanilide, acetic acid amide, ε-caprolactam, δ-valerolactam, γ-butyrolactam.
(7) Acid imide compounds: succinimide, maleimide.

(8) Imidazole compounds: imidazole, 2-methylimidazole.
(9) Urea compounds: urea, thiourea, ethyleneurea.

(10) Oxime compounds: formaldoxime, acetaldoxime, acetoxime, methyl ethyl ketoxime, cyclohexanone oxime.
(11) Amine compounds: diphenylamine, aniline, carbazole, di-n-propylamine, diisopropylamine, isopropylethylamine.

(12) Imine compounds: ethyleneimine, polyethyleneimine.
(13) Pyrazole compounds: pyrazole, 3-methylpyrazole, 3,5-dimethylpyrazole.

Among these, the thermally dissociable blocking agent preferably contains at least one selected from the group consisting of oxime compounds, pyrazole compounds, active methylene compounds, amine compounds, and acid amide compounds, and from the viewpoint of storage stability when made into a coating liquid, pyrazole compounds are more preferred.

<Polyol>
The blended composition of the present embodiment can be prepared by mixing the isocyanate group contained in the blocked polyisocyanate component with a polyol containing two or more reactive active hydrogens in the molecule. These components react with each other to form a crosslinked coating film.

Examples of polyols include, but are not limited to, acrylic polyols, polyester polyols, polyether polyols, polyolefin polyols, epoxy polyols, and fluorine polyols.

Examples of acrylic polyols include, but are not limited to, acrylic esters having active hydrogen such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, and 2-hydroxybutyl acrylate, or monoesters of acrylic acid or methacrylic acid of glycerin, and monoesters of acrylic acid or methacrylic acid of trimethylolpropane, either alone or in admixture; acrylic esters such as methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, and 2-ethylhexyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl methacrylate, 3-hydroxypropyl methacrylate, 4-hydroxypropyl methacrylate, and the like. Examples of acrylic polyols include acrylic polyols obtained by polymerizing a methacrylic acid ester having active hydrogen such as hydroxybutyl, or a methacrylic acid ester such as methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-hexyl methacrylate, lauryl methacrylate, or the like, alone or in combination, in the presence or absence of a monomer selected from the group consisting of unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, and itaconic acid, unsaturated amides such as acrylamide, N-methylol acrylamide, and diacetone acrylamide, and other polymerizable monomers such as glycidyl methacrylate, styrene, vinyl toluene, vinyl acetate, acrylonitrile, and dibutyl fumarate.

The polyester polyols include, but are not limited to, polyester polyols obtained by a condensation reaction of a dibasic acid selected from the group of carboxylic acids such as succinic acid, adipic acid, sebacic acid, dimer acid, maleic anhydride, phthalic anhydride, isophthalic acid, and terephthalic acid, or a mixture thereof, and a polyhydric alcohol selected from the group of ethylene glycol, propylene glycol, diethylene glycol, neopentyl glycol, trimethylolpropane, and glycerin, or a mixture thereof. These polyester polyols can be modified with aromatic diisocyanates, aliphatic diisocyanates, alicyclic diisocyanates, and polyisocyanates obtained therefrom. In this case, polyester polyols modified with aliphatic diisocyanates, alicyclic diisocyanates, and polyisocyanates obtained therefrom are particularly preferred in terms of weather resistance, yellowing resistance, and the like.

Examples of polyether polyols include, but are not limited to, polyether polyols obtained by randomly or block-adding alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, cyclohexene oxide, and styrene oxide to a single or mixture of polyols having a molecular weight of 500 or less using hydroxides of lithium, sodium, potassium, etc., alcoholates, alkylamines, and other strong basic catalysts, and composite metal cyanide complexes such as metal porphyrins and zinc hexacyanocobaltate complexes, as well as polyether polyols obtained by reacting alkylene oxides with polyamine compounds such as ethylenediamines, and so-called polymer polyols obtained by polymerizing acrylamide and the like using these polyethers as a medium.

Examples of polyolefin polyols include, but are not limited to, polybutadiene having two or more hydroxyl groups, hydrogenated polybutadiene, polyisoprene, and hydrogenated polyisoprene.

Epoxy polyols include, but are not limited to, novolac type, β-methyl epichlorohydrin type, cyclic oxirane type, glycidyl ether type, glycol ether type, epoxy type of aliphatic unsaturated compounds, epoxidized fatty acid ester type, polycarboxylic acid ester type, aminoglycidyl type, halogenated type, resorcinol type, and compounds modified with amino compounds, polyamide compounds, etc.

Fluorine polyols are polyols that contain fluorine in the molecule, and include, but are not limited to, copolymers of fluoroolefins, cyclohexyl vinyl ethers, hydroxyalkyl vinyl ethers, and monocarboxylic acid vinyl esters, as disclosed in U.S. Pat. No. 4,345,057 and European Patent No. 180,962, among others.

Fluorine polyols are polymeric compounds that contain fluorine in the molecule, and although there are no limitations, it is preferable that one molecule has two or more hydroxyl groups. Examples include copolymers of fluoroolefins and vinyl ethers, copolymers of fluoroolefins and vinyl esters, copolymers of fluoroolefins and (meth)acrylic esters, etc., and include those that are soluble in solvents.

The fluorine content in the fluoropolyol is preferably 2.0% by mass or more and 50% by mass or less. From the viewpoint of obtaining a coating film having excellent blocking resistance, the fluorine content in the fluoropolyol is more preferably 5.0% by mass or more, and even more preferably 10.0% by mass or more. Furthermore, from the viewpoint of obtaining a coating film having excellent compatibility with the base agent, curability, and solvent resistance, the fluorine content in the fluoropolyol is more preferably 45% by mass or less, and even more preferably 40% by mass or less.

Examples of fluorine-containing polyols that can be used include those disclosed in U.S. Pat. No. 4,345,057 and European Patent No. 180,962, Lumiflon LF100, LF200, LF400, LF600, and 800 from AGC, Zeffle GK-500, GK-510, GK-550, GK-570, and GK-580 from Daikin Industries, Ltd., Cefralcoat 703 and 705 from Central Glass Co., Ltd., and Fluonate K-700, K-702, K-704, K-705, K-707, and WZQ-660 from DIC Corporation. Fluorine-containing polyols may be used alone or in combination of two or more.

[Fluoropolyol content]
Among these fluorine polyols, materials containing 10 mass% or more of fluorine are preferred from the viewpoint of achieving both curability and blocking resistance. In this case, by setting the fluorine content and the hydroxyl value within the above-mentioned ranges, it is possible to exhibit the desired performance.

[Hydroxyl value]
In this embodiment, the hydroxyl value of the fluorine polyol used as a constituent of the blended composition is preferably 30 to 200 mgKOH/g, and the acid value is preferably 0 to 30 mgKOH/g. Two or more of these polyols may be used in combination. Among them, the hydroxyl value of the polyol used is preferably 50 to 150 mgKOH/g and the acid value is preferably 2 to 20 mgKOH/g in terms of curability, crosslink density, and solvent resistance.

<Structure of blocked polyisocyanate component>
The blocked polyisocyanate component used as a raw material for the blended composition of the present embodiment is obtained by reacting an isocyanate group contained in a polyisocyanate component obtained from a diisocyanate other than the thermally dissociable blocking agent and one or more alcohols with the thermally dissociable blocking agent.

The polyisocyanate component derived from the above diisocyanate is not particularly limited, but examples thereof include the polyisocyanates shown in (a) to (h) below.
(a): A polyisocyanate having a uretdione group obtained by cyclodimerization of two isocyanate groups.
(b): 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): 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): Polyisocyanate having an allophanate group obtained by reacting two isocyanate groups with one hydroxyl group.
(g): Polyisocyanate having an acylurea group obtained by reacting one isocyanate group with one carboxy group.
(h): Polyisocyanates having a urea group obtained by reacting one isocyanate group with one primary or secondary amine.

Among them, the polyisocyanate compound is preferably one having an isocyanurate group and an allophanate group. That is, the polyisocyanate compound may contain a mixture of polyisocyanate compounds having one of these functional groups, or may contain a mixture of polyisocyanate compounds having two or more of these functional groups, or may contain a polyisocyanate compound having a functional group other than the above two types.

The isocyanurate group is a functional group obtained by cyclotrimerizing three isocyanate groups, and has a structure represented by the following formula (I).
The allophanate group is a functional group formed by the reaction of a hydroxyl group of an alcohol with an isocyanate group, and has a structure represented by the following formula (II).

The uretdione group is a functional group obtained by cyclization dimerization of two isocyanate groups, and has a structure represented by the following formula (III).
The iminooxadiazinedione group is a functional group obtained by cyclization trimerization of three isocyanate groups, and has a structure represented by the following formula (IV).

In the polyisocyanate compound used in this embodiment, the molar ratio of isocyanurate groups relative to the total molar amount (100 mol%) of isocyanurate groups, allophanate groups, uretdione groups, and iminooxadiazinedione groups is preferably 20.0 mol% or more and 90.0 mol% or less, and more preferably 30.0 mol% or more and 80.0 mol% or less. When the molar ratio of isocyanurate groups is in the above range, the hardness and water resistance of the resulting coating film are superior.

In the blocked polyisocyanate component of this embodiment, the molar ratio of allophanate groups relative to the total molar amount (100 mol%) of isocyanurate groups, allophanate groups, uretdione groups, and iminooxadiazinedione groups is preferably 10.0 mol% or more and 90.0 mol% or less, and more preferably 15.0 mol% or more and 80.0 mol% or less.

In order to obtain a coating film having excellent compatibility with the base agent, curability, and crosslink density, the blocked polyisocyanate component has a molar ratio of [isocyanurate group/(isocyanurate group+allophanate group)] of 0.1 or more and 0.9 or less. In order to obtain a coating film having excellent curability, crosslink density, and blocking resistance, the molar ratio is preferably 0.2 or more, and more preferably 0.3 or more. In order to improve compatibility with the base agent, the molar ratio is preferably 0.95 or less, and more preferably 0.90 or less.

In the blocked polyisocyanate component used in this embodiment, the total content of uretdione groups relative to the total molar amount (100 mol%) of isocyanurate groups, allophanate groups, uretdione groups, and iminooxadiazinedione groups is preferably 0.1 mol% or more and 10.0 mol% or less, and more preferably 0.2 mol% or more and 5.0 mol% or less, from the viewpoint of achieving both compatibility with the base agent and curability.

In the blocked polyisocyanate compound used in this embodiment, the molar ratio of iminooxadiazinedione groups relative to the total molar amount (100 mol%) of isocyanurate groups, allophanate groups, uretdione groups, and iminooxadiazinedione groups is preferably 0.05 mol% or more and 3.5 mol% or less, and more preferably 0.08 mol% or more and 3.0 mol% or less.

In the blocked polyisocyanate compound used in this embodiment, in addition to the four types of bonds, bonds such as urethane groups, urea groups, acylurea groups, biuret groups, and oxadiazinetrione groups may be contained. Among them, in terms of curability, blocking resistance, and solvent resistance, it is preferable that the molar ratio of urethane groups/isocyanurate groups is 0.3 or less for the urethane groups. Furthermore, it is preferable that the molar ratio of the bonds is 0.01 mol% or more and 10.0 mol% or less in addition to the total molar amount (100 mol%) of isocyanurate groups, allophanate groups, uretdione groups, and iminooxadiazinedione groups.

These blocked polyisocyanate components can be used alone or in combination of two or more.

(average number of isocyanate groups per molecule)
The average number of isocyanate groups per molecule of the polyisocyanate component that is a precursor of the blocked polyisocyanate component used in this embodiment is, from the viewpoint of obtaining a coating film that is excellent in curability, crosslink density, and blocking resistance, preferably from 2.8 to 6.2, more preferably from 3.0 to 6.0, and even more preferably from 4.0 to 6.0.
The average number of isocyanate groups per molecule is the number of isocyanate functional groups statistically contained in one molecule of a polyisocyanate compound, and can be calculated from the number average molecular weight (Mn) and the isocyanate group content (NCO%) of the polyisocyanate compound using the following formula.

[Average number of isocyanate groups per molecule] = Mn x NCO% / 4,200

(NCO/OH)
When a blended composition is prepared using the blocked polyisocyanate component of this embodiment and a polyol, the molar ratio (NCO/OH) of the isocyanate group bonded to the thermally dissociable blocking agent in the blocked polyisocyanate component to the hydroxyl group in the polyol is 0.05/1.0 or more and 1.2/1.0 or less. Among these, from the viewpoint of achieving compatibility with the base agent and obtaining a coating film excellent in curability, crosslink density, blocking resistance, and solvent resistance, it is more preferably 0.20/1.0 or more and 1.0/1.0 or less, and even more preferably 0.30/1.0 or more and 0.90/1.0 or less.

<Production method of blocked polyisocyanate component>
The blocked polyisocyanate component of the present embodiment can be produced by the following Production Methods 1 to 3.
Production method 1: A method in which a diisocyanate, one or more alcohols, and a thermal dissociation blocking agent are reacted all at once.
Production method 2: A method in which a polyisocyanate component as a precursor is obtained by reacting a diisocyanate with one or more alcohols as raw materials, and this polyisocyanate component is then reacted with a thermally dissociable blocking agent to protect the terminal isocyanate groups.
Production method 3: A method in which a diisocyanate is reacted with a thermally dissociable blocking agent in advance, and then the remaining isocyanate groups are reacted with one or more alcohols.

Of the above manufacturing methods 1 to 3, manufacturing method 2 is preferred in terms of ease of manufacturing and ease of design.
The methods for producing the polyisocyanate components containing each bond are shown below.

<Production method of polyisocyanate component>
(1) Method for Producing Polyisocyanate Compound Containing Isocyanurate Groups Although there is no particular limitation on the method for producing a polyisocyanate containing an isocyanurate group, for example, a method in which a diisocyanate is subjected to an isocyanurate reaction using a catalyst or the like, the reaction is stopped when a predetermined conversion rate is reached, and unreacted diisocyanate is removed can be mentioned.

The catalyst used in the isocyanurate reaction is not particularly limited, but is preferably one that exhibits basicity, and specific examples include tetraalkylammonium hydroxides and weak organic acid salts, hydroxyalkylammonium hydroxides and weak organic acid salts, alkali metal salts of alkyl carboxylic acids, metal alcoholates, aminosilyl group-containing compounds, Mannich bases, combinations of tertiary amines and epoxy compounds, phosphorus-based compounds, etc.

Examples of tetraalkylammonium include tetramethylammonium and tetraethylammonium.

Examples of organic weak acids include acetic acid and capric acid. Examples of hydroxyalkyl ammonium include trimethylhydroxypropyl ammonium, trimethylhydroxyethyl ammonium, triethylhydroxypropyl ammonium, and triethylhydroxyethyl ammonium.

Examples of alkyl carboxylic acids include acetic acid, caproic acid, octylic acid, and myristic acid.

Metals that make up alkali metal salts include, for example, tin, zinc, lead, etc.

Examples of metal alcoholates include sodium alcoholate and potassium alcoholate.

Examples of aminosilyl group-containing compounds include hexamethyldisilazane.

Examples of phosphorus compounds include tributylphosphine.

The amount of these catalysts used is preferably 10 ppm or more and 1.0% or less based on the total mass of the raw material diisocyanate (and alcohol, if necessary). In order to terminate the isocyanurate reaction, the catalyst may be inactivated by adding an acidic substance that neutralizes the catalyst, thermal decomposition, chemical decomposition, etc. Examples of acidic substances that neutralize the catalyst include phosphoric acid and acidic phosphate esters.

The yield of polyisocyanate generally tends to be 10% by mass or more and 70% by mass or less, and preferably 35% by mass or more and 60% by mass or less. Polyisocyanate obtained with a higher yield tends to have a higher viscosity. The yield can be calculated from the ratio of the mass of the obtained polyisocyanate to the total mass of the raw material components.

The reaction temperature of the isocyanurate 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 equal to or higher than the lower limit, the reaction tends to proceed more easily, and when the reaction temperature is equal to or lower than the upper limit, side reactions that cause coloring tend to be suppressed more effectively.

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

After completion of the isocyanurate reaction, it is preferable to remove unreacted diisocyanate by thin film evaporator, extraction, etc. Even if the polyisocyanate contains unreacted diisocyanate, the content of diisocyanate is preferably 3.0 mass% or less, more preferably 1.0 mass% or less, and even more preferably 0.5 mass% or less, based on the total mass of the polyisocyanate. When the residual unreacted diisocyanate concentration is within the above range, curability tends to be more excellent.
The concentration of the residual unreacted diisocyanate can be measured by gas chromatography analysis.

(2) Method for Producing Polyisocyanate Compound Containing Allophanate Groups Polyisocyanates containing allophanate groups can be produced, for example, by adding an alcohol to a diisocyanate and using an allophanate reaction catalyst.

The alcohol used to form the allophanate group is preferably an alcohol formed only from carbon, hydrogen and oxygen.
Specific examples of the alcohol include, but are not limited to, monoalcohols, dialcohols, etc. These alcohols may be used alone or in combination of two or more.

Examples of monoalcohols include methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, and nonanol.
Examples of the dialcohol include ethylene glycol, 1,3-butanediol, neopentyl glycol, and 2-ethylhexanediol.

The ratio of the molar amount of isocyanate groups of the diisocyanate to the molar amount of hydroxyl groups of the alcohol is preferably 10/1 or more and 1000/1 or less, and more preferably 100/1 or more and 1000/1 or less. When the molar ratio is equal to or more than the lower limit, the average number of isocyanate groups per molecule can be more sufficiently ensured. When the molar ratio is equal to or less than the upper limit, the effect of excellent surface hardness is achieved.

Examples of the allophanate reaction catalyst include, but are not limited to, alkyl carboxylates of tin, lead, zinc, bismuth, zirconium, zirconyl, and the like.
Examples of tin alkylcarboxylates (organotin compounds) include tin 2-ethylhexanoate and dibutyltin dilaurate.
An example of the alkyl carboxylate of lead (organic lead compound) is lead 2-ethylhexanoate.
Examples of zinc alkylcarboxylates (organic zinc compounds) include zinc 2-ethylhexanoate.
An example of the alkyl carboxylate of bismuth is bismuth 2-ethylhexanoate.
An example of the zirconium alkylcarboxylate is zirconium 2-ethylhexanoate.
An example of the zirconyl alkylcarboxylate is zirconyl 2-ethylhexanoate. These catalysts can be used alone or in combination of two or more.

The above-mentioned isocyanurate-forming reaction catalyst can also serve as an allophanate-forming reaction catalyst. When the allophanate-forming reaction is carried out using the above-mentioned isocyanurate-forming reaction catalyst, an isocyanurate-type polyisocyanate is naturally produced.
Among these, it is preferable from the viewpoint of economical production to carry out the allophanate formation reaction and the isocyanurate formation reaction using the above-mentioned isocyanurate formation catalyst as the allophanate formation reaction catalyst.

The upper limit of the amount of the allophanate reaction catalyst used is preferably 10,000 ppm by mass, more preferably 1,000 ppm by mass, and even more preferably 500 ppm by mass, relative to the mass of the charged diisocyanate. On the other hand, the lower limit of the amount of the isocyanurate reaction catalyst used is not particularly limited, but may be, for example, 10 ppm by mass.

The lower limit of the allophanate reaction temperature is preferably 60°C, more preferably 70°C, even more preferably 80°C, and particularly preferably 90°C. On the other hand, the upper limit of the allophanate reaction temperature is preferably 160°C, more preferably 155°C, even more preferably 150°C, and particularly preferably 145°C.

That is, the allophanate reaction temperature is preferably 60°C or higher and 160°C or lower, more preferably 70°C or higher and 155°C or lower, further preferably 80°C or higher and 150°C or lower, and particularly preferably 90°C or higher and 145°C or lower.
By setting the allophanate formation reaction temperature to the above lower limit or higher, it is possible to further increase the reaction rate. By setting the allophanate formation reaction temperature to the above upper limit or lower, it is likely that changes in properties such as coloration of the polyisocyanate can be more effectively suppressed.

The lower limit of the allophanate reaction time is preferably 0.2 hours, more preferably 0.4 hours, even more preferably 0.6 hours, particularly preferably 0.8 hours, and most preferably 1 hour, while the upper limit of the allophanate reaction time is preferably 8 hours, more preferably 6 hours, even more preferably 4 hours, particularly preferably 3 hours, and most preferably 2 hours.
That is, the allophanate reaction time is preferably from 0.2 to 8 hours, more preferably from 0.4 to 6 hours, even more preferably from 0.6 to 4 hours, particularly preferably from 0.8 to 3 hours, and most preferably from 1 to 2 hours.
By setting the allophanate formation reaction time to be equal to or more than the above lower limit, the viscosity of the polyisocyanate can be made lower, while by setting the allophanate formation reaction time to be equal to or less than the above upper limit, changes in properties such as coloration of the polyisocyanate tend to be more effectively suppressed.

When the desired yield is reached, the allophanation reaction is stopped by adding a deactivator for the allophanation reaction catalyst, such as phosphoric acid or methyl paratoluenesulfonate.

(3) Method for Producing Polyisocyanate Compound Containing Uretdione Groups As a method for producing a polyisocyanate compound containing uretdione groups, a method using a uretdione reaction catalyst can be mentioned.

Specific examples of the uretdione reaction catalyst include, but are not limited to, tertiary phosphines, such as trialkylphosphines, tri-n-butylphosphine, tri-n-octylphosphine, etc.; tris(dialkylamino)phosphines, such as tris-(dimethylamino)phosphine; and cycloalkylphosphines, such as cyclohexyl-di-n-hexylphosphine.
Many of these compounds also accelerate the isocyanuration reaction at the same time, producing an isocyanurate group-containing polyisocyanate in addition to a uretdione group-containing polyisocyanate.

When the desired yield is reached, a deactivator for the uretdione reaction catalyst, such as phosphoric acid or methyl paratoluenesulfonate, is added to stop the uretdione reaction.

The above-mentioned catalyst is preferably used in an amount of 10 ppm by mass or more and 10,000 ppm by mass or less, more preferably 10 ppm by mass or more and 1,000 ppm by mass or less, and even more preferably 10 ppm by mass or more and 500 ppm by mass or less, based on the mass of the charged diisocyanate.

It is preferable to carry out the uretdione reaction at a temperature of 20°C or higher and 120°C or lower. The lower limit of the reaction temperature is more preferably 25°C, even more preferably 30°C, and even more preferably 35°C. The upper limit of the reaction temperature is more preferably 110°C, even more preferably 100°C, and even more preferably 90°C. By keeping the uretdione reaction temperature at or below the above upper limit, changes in characteristics such as coloration tend to be more effectively suppressed.

Uretdione groups can also be obtained by heating diisocyanate without using the above-mentioned uretdione reaction catalyst. The heating temperature is preferably 130°C or higher and 180°C or lower. The lower limit of the heating temperature is more preferably 140°C, even more preferably 145°C, even more preferably 150°C, and even more preferably 155°C. The upper limit of the heating temperature is more preferably 170°C, even more preferably 165°C, even more preferably 162°C, and even more preferably 160°C.

The heating time is preferably 0.2 hours or more and 8.0 hours or less. The lower limit of the heating time is more preferably 0.4 hours, even more preferably 0.6 hours, even more preferably 0.8 hours, and even more preferably 1.0 hours. The upper limit of the heating time is more preferably 6.0 hours, even more preferably 4.0 hours, even more preferably 3.0 hours, and even more preferably 2.0 hours. By setting the heating time to the above lower limit or more, it tends to be possible to further achieve a low viscosity, and by setting it to the above upper limit or less, it tends to be possible to further suppress coloration of the polyisocyanate itself.

When the polyisocyanate composition of the present embodiment is obtained without using a uretdione reaction catalyst, it is preferable to remove the unreacted diisocyanate after the uretdione reaction by heating alone and the above-mentioned isocyanurate reaction are completed, from the viewpoints of reducing the concentration of unreacted diisocyanate, reducing the rate of change in molecular weight after storage of the obtained polyisocyanate composition, and reducing yellowing during high-temperature baking.

(4) Method for Producing Polyisocyanate Compound Containing Iminooxadiazinedione Group The catalyst for deriving a polyisocyanate containing an iminooxadiazinedione group from a diisocyanate is not particularly limited, but for example, the following catalyst (i) or (ii), which is generally known as a catalyst for iminooxadiazinedione formation reaction, can be used.

(i) (Poly)hydrogen fluorides represented by the general formula M[Fn] or the general formula M[Fn(HF)m], such as tetramethylammonium fluoride hydrate and tetraethylammonium fluoride (wherein m and n are integers satisfying the relationship m/n>0, and M represents an n-charged cation (mixture) or one or more radicals having a valence of n in total).
(ii) Compounds of the general formula R1-CR'2-C(O)O-, or the general formula R2=CR'-C(O)O- (wherein R1 and R2 represent a branched, cyclic, and/or unsaturated perfluoroalkyl group having 1 to 30 carbon atoms as required, and R' is the same or different and is selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, and an aryl group, and optionally contains a heteroatom), such as 3,3,3-trifluorocarboxylic acid; 4,4,4,3,3-pentafluorobutanoic acid; 5,5,5,4,4,3,3-heptafluoropentanoic acid; 3,3-difluoroprop-2-enoic acid, and a quaternary ammonium cation or a quaternary phosphonium cation.

From the viewpoint of availability, the above (i) is preferred, and from the viewpoint of safety, the above (ii) is preferred.
The amount of the iminooxadiazinedione reaction catalyst is preferably 10 ppm or more and 1000 ppm or less based on the mass of the charged diisocyanate. The lower limit is more preferably 20 ppm, even more preferably 40 ppm, and still more preferably 80 ppm.
The upper limit is more preferably 800 ppm, further preferably 600 ppm, and even more preferably 500 ppm or less.

The temperature of the iminooxadiazinedione reaction is preferably 40° C. or higher and 120° C. or lower.
The lower limit is more preferably 50° C., and even more preferably 55° C. The upper limit is more preferably 100° C., and even more preferably 90° C., and even more preferably 80° C.
By setting the iminooxadiazinedione reaction temperature to 40° C. or higher, it tends to be possible to maintain a high reaction rate. By setting the iminooxadiazinedione reaction temperature to 120° C. or lower, it tends to be possible to effectively suppress coloration of the polyisocyanate, etc.

<Physical properties of polyisocyanate compounds>
The viscosity at 25°C of the polyisocyanate compound produced by the above-mentioned production method is preferably 300 mPa·s or more and 50,000 mPa·s or less, from the viewpoints of improving the dispersibility and pot life of the coating composition and improving the appearance and water resistance when formed into a coating film.
The lower limit of the viscosity is more preferably 350 mPa·s, and even more preferably 450 mPa·s, from the viewpoint of improving the water resistance, weather resistance, etc., of the formed coating film. On the other hand, the upper limit of the viscosity is more preferably 40,000 mPa·s, and even more preferably 30,000 mPa·s, from the viewpoint of improving dispersibility.
The viscosity of the polyisocyanate compound can be measured at 25° C., for example, with an E-type viscometer (manufactured by Tokimec Co., Ltd.) using a standard rotor (1° 34′×R24).

The isocyanate group content (NCO%) of the polyisocyanate compound, excluding unreacted aliphatic diisocyanate, is preferably 12% by mass or more and 25% by mass or less, more preferably 13% by mass or more and 24% by mass or less, and even more preferably 15% by mass or more and 24% by mass or less.
By making the isocyanate group content equal to or more than the lower limit, the water resistance and weather resistance of the coating film formed can be improved, whereas by making the isocyanate group content equal to or less than the upper limit, the dispersibility of the coating composition can be improved.
The isocyanate group content (NCO %) of the polyisocyanate compound can be measured by the titration method described in the Examples below.

The number average molecular weight of the polyisocyanate compound is preferably from 450 to 4,000, more preferably from 500 to 3,500, and even more preferably from 550 to 3,000, from the viewpoint of the solvent resistance of the coating film.
The number average molecular weight can be measured, for example, by using gel permeation chromatography (GPC).

Blocking reaction
The reaction step of the present embodiment between the polyisocyanate component and the thermally dissociable blocking agent can be carried out regardless of the presence or absence of a solvent. When a solvent is used, it is preferable to use a solvent that is inactive to the isocyanate group.
In the blocking reaction, organic metal salts of tin, zinc, lead, etc., metal alcoholates such as sodium methylate, sodium ethylate, sodium phenolate, potassium methylate, etc., and tertiary amines may be used as catalysts.
At least a part of the catalyst used in the blocking reaction may be neutralized with an acidic compound such as those described below. Neutralization is preferable because it improves the thermal stability of the blocked polyisocyanate component. Examples of the acidic compound include inorganic acids such as hydrochloric acid, phosphorous acid, and phosphoric acid, sulfonic acids such as methanesulfonic acid and p-toluenesulfonic acid, and phosphate esters such as ethyl phosphate, diethyl phosphate, isopropyl phosphate, diisopropyl phosphate, butyl phosphate, dibutyl phosphate, 2-ethylhexyl phosphate, and di(2-ethylhexyl) phosphate. The amount of the acidic compound is preferably in the range of 0.3 to 3 equivalents, more preferably 0.5 to 2 equivalents, and even more preferably 0.7 to 1.5 equivalents, relative to the catalyst.
The reaction temperature is preferably −20° C. or higher and 150° C. or lower, and the reaction time is preferably 30 minutes or longer and 48 hours or shorter.

<Physical properties of blocked polyisocyanate component>
(Available Isocyanate Group (NCO) Content)
In the blocked polyisocyanate component used in the present embodiment, the effective NCO content per solid content is not particularly limited, but is preferably 1% by mass or more and 20% by mass or less, more preferably 2% by mass or more and 18% by mass or less, and even more preferably 3% by mass or more and 16% by mass or less, in order to improve the compatibility and curability of the blocked polyisocyanate component and the polyol. The effective NCO content can be calculated using the method described in the examples below.

(Number average molecular weight)
The number average molecular weight of the blocked polyisocyanate of this embodiment is preferably 900 or more and 3,000 or less. From the viewpoint of obtaining a coating film excellent in curability, crosslink density, and blocking resistance, the number average molecular weight of the blocked polyisocyanate is more preferably 1,000 or more, and even more preferably 1,200 or more. Furthermore, from the viewpoint of improving compatibility with the base agent, the number average molecular weight of the blocked polyisocyanate is more preferably 2,500 or less, and even more preferably 2,000 or less.
Furthermore, the mass fraction of the blocked isocyanate having a number average molecular weight of 1,000 or less contained in the blocked isocyanate component is from 5.0 mass % to 50.0 mass %, and preferably from 10.0 mass % to 40.0 mass %, from the viewpoint of achieving both compatibility with the base resin and the ability to obtain a coating film excellent in curability and crosslink density.
The number average molecular weight can be measured, for example, by using gel permeation chromatography (GPC).

The blended composition of this embodiment contains the blocked polyisocyanate component and a polyol, but may also contain polyhydric active hydrogen compounds other than the polyol, such as polyamines, alkanolamines, polythiols, and polyols. Among these, polyols are preferred.

The polyamine is not particularly limited, but examples thereof include diamines such as ethylenediamine, propylenediamine, butylenediamine, triethylenediamine, hexamethylenediamine, 4,4'-diaminodicyclohexylmethane, piperazine, 2-methylpiperazine, and isophoronediamine; linear polyamines having three or more amino groups such as bishexamethylenetriamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentamethylenehexamine, and tetrapropylenepentamine; and cyclic polyamines such as 1,4,7,10,13,16-hexaazacyclooctadecane, 1,4,7,10-tetraazacyclodecane, 1,4,8,12-tetraazacyclopentadecane, and 1,4,8,11-tetraazacyclotetradecane.

Examples of alkanolamines include, but are not limited to, monoethanolamine, diethanolamine, aminoethylethanolamine, N-(2-hydroxypropyl)ethylenediamine, mono-, di-(n- or iso-)propanolamine, ethylene glycol-bis-propylamine, neopentanolamine, and methylethanolamine.

Polythiols include, but are not limited to, bis-(2-hydrothioethyloxy)methane, dithioethylene glycol, dithioerythritol, and dithiothreitol.

Other hardeners
The blended composition of the present embodiment may contain other curing agents such as melamine-based curing agents and epoxy-based curing agents as curing agents in addition to the blocked polyisocyanate component. The melamine-based curing agent is not particularly limited, but examples thereof include fully alkyl etherified melamine resins, methylol group-type melamine resins, and imino group-type melamine resins having imino groups in some parts. When using a melamine-based curing agent in combination, it is effective to add an acidic compound. Specific examples of the acidic compound include carboxylic acids, sulfonic acids, acidic phosphates, and phosphites.

Carboxylic acids include, but are not limited to, acetic acid, lactic acid, succinic acid, oxalic acid, maleic acid, and decane dicarboxylic acid. Sulfonic acids include, but are not limited to, paratoluenesulfonic acid, dodecylbenzenesulfonic acid, and dinonylnaphthalenedisulfonic acid. Acidic phosphate esters include, but are not limited to, dimethyl phosphate, diethyl phosphate, dibutyl phosphate, dioctyl phosphate, dilauryl phosphate, monomethyl phosphate, monoethyl phosphate, monobutyl phosphate, and monooctyl phosphate. Phosphite esters include, but are not limited to, diethyl phosphite, dibutyl phosphite, dioctyl phosphite, dilauryl phosphite, monoethyl phosphite, monobutyl phosphite, monooctyl phosphite, and monolauryl phosphite.

Epoxy curing agents are not particularly limited, but examples include aliphatic polyamines, alicyclic polyamines, aromatic polyamines, acid anhydrides, phenol novolacs, polymercaptans, aliphatic tertiary amines, aromatic tertiary amines, imidazole compounds, and Lewis acid complexes.

<Other ingredients>
In addition to the blocked polyisocyanate component and the polyol, the blended composition of the present embodiment may contain various additives used in the relevant technical field, such as solvents, coloring pigments, dyes, silane coupling agents for improving adhesion of the coating film, ultraviolet absorbers, curing accelerators, light stabilizers, matting agents, coating surface hydrophilizing agents, curing acceleration catalysts, drying improvers, leveling agents, antioxidants, plasticizers, surfactants, etc., depending on the purpose and application, within a range that does not impair the effects of the present invention.
Examples of the solvent include aliphatic hydrocarbon solvents, alicyclic hydrocarbon solvents, ketone solvents, ester solvents, aromatic solvents, glycol solvents, ether solvents, halogenated hydrocarbon solvents, pyrrolidone solvents, amide solvents, sulfoxide solvents, lactone solvents, and amine solvents.

Examples of aliphatic hydrocarbon solvents include hexane, heptane, and octane.

Examples of alicyclic hydrocarbon solvents include cyclohexane and methylcyclohexane.

Examples of ketone solvents include acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, and diacetone alcohol.

Examples of ester-based solvents include methyl acetate, ethyl acetate, butyl acetate, isobutyl acetate, methyl lactate, and ethyl lactate.

Examples of aromatic solvents include toluene, xylene, diethylbenzene, mesitylene, anisole, benzyl alcohol, phenyl glycol, and chlorobenzene.

Examples of glycol solvents include ethylene glycol monoethyl ether acetate, 3-methyl-3-methoxybutyl acetate, dipropylene glycol monomethyl ether, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol dimethyl ether, dipropylene glycol dimethyl ether, isobutanol, butyl glycol, N-methylpyrrolidone, butyl diglycol, butyl diglycol acetate, ether acetate, ethylene glycol monoisopropyl ether acetate, ethylene glycol mono-n-butyl ether acetate, ethylene glycol diacetate, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol di-n-propyl ether, ethylene glycol diisopropyl ether, ethylene glycol di-n-butyl ether, ethylene glycol methyl ethyl ether, ethylene glycol methyl isopropyl ether, ethylene glycol methyl-n-butyl ether, ether, ethylene glycol ethyl-n-propyl ether, ethylene glycol ethyl isopropyl ether, ethylene glycol ethyl-n-butyl ether, ethylene glycol-n-propyl-n-butyl ether, ethylene glycol isopropyl-n-butyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol mono-n-propyl ether acetate, diethylene glycol monoisopropyl ether acetate, diethylene glycol mono-n-butyl ether acetate, diethylene glycol diacetate, diethylene glycol diethyl ether, diethylene glycol di-n-propyl ether, diethylene glycol diisopropyl ether, diethylene glycol di-n-butyl ether, diethylene glycol methyl ethyl ether, diethylene glycol methyl isopropyl ether, diethylene glycol methyl-n-propyl ether, diethylene glycol methyl-n-butyl ether, diethylene glycol ethyl isopropyl ether, diethylene glycol ethyl-n-propyl propyl ether, diethylene glycol ethyl-n-butyl ether, diethylene glycol-n-propyl-n-butyl ether, diethylene glycol isopropyl-n-butyl ether, and propylene glycol-based propylene glycol monoethyl ether acetate, propylene glycol mono-n-propyl ether acetate, propylene glycol monoisopropyl ether acetate, propylene glycol mono-n-butyl ether acetate, propylene glycol diacetate, propylene glycol diethyl ether, propylene glycol di-n-propyl ether, propylene glycol diisopropyl ether, propylene glycol di-n-butyl ether, propylene glycol methyl ethyl ether, propylene glycol methyl isopropyl ether, propylene glycol methyl-n-butyl ether, propylene glycol ethyl-n-propyl ether, propylene glycol ethyl isopropyl ether, propylene glycol ethyl-n-butyl ether, propylene glycol-n-propyl-n-butyl ether, and propylene glycol isopropyl -n-butyl ether, dipropylene glycol monomethyl ether acetate, dipropylene glycol monoethyl ether acetate, dipropylene glycol mono-n-propyl ether acetate, dipropylene glycol monoisopropyl ether acetate, dipropylene glycol mono-n-butyl ether acetate, dipropylene glycol diacetate, dipropylene glycol diethyl ether, dipropylene glycol di-n-propyl ether, dipropylene glycol diisopropyl ether, dipropylene glycol di-n-butyl ether, dipropylene glycol methyl ethyl ether, dipropylene glycol methyl isopropyl ether, dipropylene glycol methyl-n-propyl ether, dipropylene glycol methyl-n-butyl ether, dipropylene glycol ethyl isopropyl ether, dipropylene glycol ethyl-n-propyl ether, dipropylene glycol ethyl-n-butyl ether, dipropylene glycol-n-propyl-n-butyl ether, dipropylene glycol isopropyl-n-butyl ether, and the like.

Examples of ether solvents include diethyl ether, tetrahydrofuran, and dioxane.

Examples of halogenated hydrocarbon solvents include dichloromethane, 1,2-dichloroethane, and chloroform.

Examples of pyrrolidone-based solvents include N-methyl-2-pyrrolidone.

Examples of amide-based solvents include N,N-dimethylacetamide, N,N-dimethylformamide, and 1,3-dimethyl-2-imidazolidinone. Examples of sulfoxide-based solvents include dimethyl sulfoxide. Examples of lactone-based solvents include γ-butyrolactone. Examples of amine-based solvents include morpholine.

The boiling point of the solvent used in the compounded composition of this embodiment is preferably 70°C or higher and 250°C or lower. A low boiling point tends to provide high curability and blocking resistance. A high boiling point also tends to form a coating film with good appearance.

The color pigment may be an inorganic pigment or an organic pigment. Examples of inorganic pigments include carbon black and titanium oxide, which have good weather resistance. Examples of organic pigments include phthalocyanine blue, phthalocyanine green, quinacridone red, indanthrene orange, and isoindolinone yellow.

Examples of silane coupling agents include 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, ureidopropyltriethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, methyltriethoxysilane, methyltrimethoxysilane, etc.

Examples of UV absorbers include benzophenone-based, benzotriazole-based, triazine-based, and cyanoacrylate-based UV absorbers.

Examples of light stabilizers include hindered amine light stabilizers, and specific commercially available products include Adeka STAB LA62, Adeka STAB LA67 (trade names, all manufactured by Adeka Argus Chemical Co., Ltd.), Tinuvin 292, Tinuvin 144, Tinuvin 123, Tinuvin 440 (trade names, all manufactured by Chiba Specialty Chemicals Co., Ltd.), and Sanol LS765 (trade name, manufactured by Sankyo Lifetech Co., Ltd.).

Examples of matting agents include ultrafine synthetic silica, which, when used, can produce a coating with an elegant semi-gloss or matte finish.

As the coating surface hydrophilizing agent, a silicate compound is preferred. By including a silicate compound, when a coating film is produced using the coating composition of this embodiment, the coating film surface is made hydrophilic and resistance to rain streak contamination is expressed. Since the silicate compound reacts with hydroxyl groups, when mixed in advance, it is preferable to add it to the polyisocyanate composition, which is the hardener component. Alternatively, it may be mixed at the same time when the polyol, which is the main component, and the polyisocyanate composition, which is the hardener component, are mixed.
Examples of the silicate compound include tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, tetraisopropoxysilane, tetra-n-butoxysilane, tetraisobutoxysilane, tetra-tert-butoxysilane, dimethoxydiethoxysilane, tetraphenoxysilane, and condensates thereof. Among these, the silicate compound is preferably a condensate of tetramethoxysilane or a condensate of tetraethoxysilane, since when a coating film is produced, the surface of the coating film tends to become hydrophilic.

The catalyst for accelerating curing may include, but is not limited to, metal salts, tertiary amines, and the like.
Examples of metal salts include dibutyltin dilaurate, tin 2-ethylhexanoate, zinc 2-ethylhexanoate, cobalt salts, and the like.
Examples of tertiary amines include triethylamine, pyridine, methylpyridine, benzyldimethylamine, N,N-dimethylcyclohexylamine, N-methylpiperidine, pentamethyldiethylenetriamine, N,N'-endoethylenepiperazine, and N,N'-dimethylpiperazine.

Examples of drying improvers include CAB (cellulose acetate butyrate) and NC (nitrocellulose).

Leveling agents include, but are not limited to, silicone, aerosil, wax, stearates, polysiloxanes, etc.

The plasticizer is not particularly limited, but examples thereof include phthalate esters, phosphate esters, fatty acid esters, pyromellitic acid esters, epoxy-based plasticizers, polyether-based plasticizers, liquid rubber, and non-aromatic paraffin oil.
Examples of phthalic acid esters include dioctyl phthalate, dibutyl phthalate, diethyl phthalate, butyl benzyl phthalate, di-2-ethylhexyl phthalate, diisodecyl phthalate, diundecyl phthalate, and diisononyl phthalate.
Examples of the phosphoric acid esters include tricresyl phosphate, triethyl phosphate, tributyl phosphate, tri-2-ethylhexyl phosphate, trimethylhexyl phosphate, tris-chloroethyl phosphate, and tris-dichloropropyl phosphate.
Examples of fatty acid esters include trimellitic acid esters, dipentaerythritol esters, dioctyl adipate, dimethyl adipate, di-2-ethylhexyl azelate, dioctyl azelate, dioctyl sebacate, di-2-ethylhexyl sebacate, methyl acetyl lysinocate, etc. Examples of trimellitic acid esters include trimellitic acid octyl ester, trimellitic acid isodecyl ester, etc.
An example of the pyromellitic acid ester is pyromellitic acid octyl ester.
Examples of epoxy plasticizers include epoxidized soybean oil, epoxidized linseed oil, and epoxidized fatty acid alkyl esters.
Examples of the polyether plasticizer include adipic acid ether ester and polyether.
Examples of the liquid rubber include liquid NBR, liquid acrylic rubber, and liquid polybutadiene.

Surfactants include, for example, known anionic surfactants, cationic surfactants, amphoteric surfactants, etc.

<Paint composition>
One aspect of the present invention is a coating composition containing the blend composition of the present embodiment.

<Coating film>
The coating film of this embodiment is a cured product obtained by curing the above-mentioned coating composition.

When forming a coating film on an article, the above-mentioned compounded composition is applied to the article using a known method such as roll coating, curtain flow coating, spray coating, bell coating, electrostatic coating, etc., and then cured through a room temperature drying or baking process.

The article may be provided with a desired substrate and, optionally, a conventional primer prior to coating.
Examples of the substrate include metal, wood, glass, stone, ceramic materials, concrete, rigid and flexible plastics, textiles, leather products, paper, and the like.

The present invention will be described in more detail below with reference to examples and comparative examples. However, the present invention is not limited to the following examples as long as it does not depart from the gist of the present invention.
In the examples and comparative examples, the physical properties and evaluations of the polyisocyanate compositions were measured as follows. Unless otherwise specified, "parts" and "%" mean "parts by mass" and "% by mass".

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

(Rotation Speed)
100 rpm (when viscosity is less than 128 mPa.s)
50 rpm (for viscosity between 128 mPa·s and 256 mPa·s)
20 rpm (for viscosity between 256 mPa·s and 640 mPa·s)
10 rpm (for viscosity between 640 mPa·s and 1,280 mPa·s)
5 rpm (for viscosity between 1,280 mPa·s and 2,560 mPa·s)
2.5 rpm (2,560 mPa.s or more and less than 5,120 mPa.s)

[Property 2: Isocyanate group content (NCO%)]
The polyisocyanate compounds obtained in the synthesis examples and the polyisocyanate compositions obtained in the examples and comparative examples were used as samples to measure the isocyanate group content according to the method described in JIS K7301-1995 (Test method for tolylene diisocyanate-type prepolymers for thermosetting urethane elastomers). A more specific method for measuring the isocyanate group content (NCO%) is described below.

(1) 1 g (Wg) of a sample was placed in a 200 mL Erlenmeyer flask, and 20 mL of toluene was added to the flask to dissolve the sample.
(2) Then, 20 mL of a 2.0 N di-n-butylamine/toluene solution was added to the flask and allowed to stand for 15 minutes.
(3) 70 mL of 2-propanol was added to the flask and dissolved to obtain a solution.
(4) The solution obtained in (3) above was titrated with 1 mol/L hydrochloric acid to determine the sample titer (V1 mL).
(5) Even when no sample was added, the measurement was carried out in the same manner as in (1) to (3) above, and the blank titer (V0 mL) was calculated.

From the sample titration amount and blank titration amount obtained above, the isocyanate group content (NCO%) was calculated using the formula shown below.

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

[Property 3: Blocked isocyanate group content (effective NCO content)]
The effective NCO content of the obtained blocked polyisocyanate composition was determined as follows. The effective NCO content (mass%) here quantifies the amount of blocked isocyanate groups present in the blocked polyisocyanate component after the blocking reaction that can participate in a crosslinking reaction, and is expressed as mass% of isocyanate groups. The effective NCO content was calculated according to the formula shown below. In the formula shown below, "S" represents the non-volatile content (mass%) of the blocked polyisocyanate component. "W1" represents the mass (g) of the polyisocyanate used in the reaction. "A" represents the isocyanate group content (mass%) of the polyisocyanate. "W2" represents the mass (g) of the blocked polyisocyanate after the blocking reaction.

Effective NCO content (mass%) = {S x (W1 x A)} / W2

[Physical property 4: Number average molecular weight]
The number average molecular weight is a number average molecular weight based on polystyrene standards measured by gel permeation chromatography (GPC) using the following device. Specific measurement conditions for the GPC measurement were as follows.

Apparatus: Tosoh Corporation, HLC-802A
Column: Tosoh Corporation, G1000HXL x 1, G2000HXL x 1, G3000HXL x 1 Carrier: Tetrahydrofuran Detection method: Differential refractometer [Property 5: Mass fraction of number average molecular weight of 1,000 or less]
The number average molecular weight was measured based on polystyrene in the same manner as in Physical Property 4. From the total area of the detected GPC spectrum, the area of the portion corresponding to a number average molecular weight of 1,000 or less was calculated as a mass fraction.

[Physical property 6: Molar ratio of isocyanurate groups/(isocyanurate groups + allophanate groups)]
The ratio of isocyanurate groups to allophanate groups in the resulting blocked polyisocyanate composition was determined by ¹ H-NMR under the following specific measurement conditions.
NMR device: Bruker Biospin Avance600 (product name)
Observed nucleus: ¹ H
Frequency: 600MHz
Solvent: _CDCl3
Shift standard: TMS (0 ppm)
The ratio of the area (2H) of the signal of the hydrogen atom of the methylene group derived from HDI adjacent to the isocyanurate group at around 3.85 ppm to the area (1H) of the signal of the hydrogen atom bonded to the nitrogen of the allophanate bond at around 8.50 ppm was measured and calculated.
Isocyanurate group/(isocyanate group+allophanate group)=(signal area near 3.85 ppm/6)/(signal area near 3.85 ppm/6+signal area near 8.50 ppm)

[Physical property 7: Molar ratio of urethane group/isocyanurate group]
The molar ratio of urethane groups to isocyanurate groups in the resulting blocked polyisocyanate composition was determined by ¹³ C-NMR measurement under the following specific measurement conditions.
^13C -NMR device: AVANCE600 (manufactured by Bruker)
Cryoprobe (manufactured by Bruker)
CryoProbe®
CPDUL
600S3-C/HD-05Z
Resonance frequency: 150MHz
Concentration: 60wt/vol%
Solvent, shift reference: CDCl ₃ (77 ppm)
Number of accumulations: 10,000 Pulse program: zgpg30 (proton complete decoupling method, waiting time 2 sec)
Urethane group/isocyanurate group={(integral value around 156 to 157 ppm)−(integral value around 154 ppm)}/(integral value around 148.6 ppm)

[Property 8: Average number of isocyanate groups per molecule]
The average number of isocyanate groups per molecule of the polyisocyanate composition was calculated from the following formula based on the number average molecular weight (Mn) and post isocyanate group content (NCO%) of the polyisocyanate composition measured as described above.
[Average number of isocyanate groups per molecule] = Mn × NCO% / 4,200

[Physical Property 9: Hydroxyl Value of Polyol]
The hydroxyl value of the polyol was determined according to JIS K 0070:1992 using a polyol as a sample. Specifically, 12.5 g of acetic anhydride was diluted with 50 mL of pyridine to prepare an acetylation reagent. Next, 2.5 to 5.0 g of polyol was precisely weighed into a 100 mL eggplant flask. 5 mL of the acetylation reagent and 10 mL of toluene were added to the eggplant flask using a whole pipette, and then a cooling tube was attached and the mixture was heated and stirred at 100°C for 1 hour. 2.5 mL of distilled water was added using a whole pipette, and the mixture was heated and stirred for another 10 min. After cooling for 2 to 3 minutes, 12.5 mL of ethanol was added, and 2 to 3 drops of phenolphthalein were added as an indicator, followed by titration with 0.5 mol/L ethanolic 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 recovery flask, heated and stirred for 10 minutes, and then titrated in the same manner. Based on this result, the hydroxyl value was calculated using the following formula (4).
OH number (mg-KOH/g) = {(b-a) x 28.05 x f}/e ... (4)
In formula (4), a represents the titer (mL) of the sample, b represents the titer (mL) of the blank test, e represents the sample mass (g), and f represents the factor of the titrant.
[Physical Property 10: Fluorine Content]
The fluorine content was measured by burning a sample in the presence of oxygen, capturing the generated hydrogen fluoride in water, measuring the aqueous solution by ion chromatography, and calculating the fluorine content in the sample.

<Adjustment method>
[Preparation Example 1]
The blocked polyisocyanate component obtained in the synthesis example and a fluorine polyol (product name: Zeffle GK-570, manufactured by Daikin Industries, Ltd., solid content: 65 mass%, hydroxyl value: 63 mgKOH/g, fluorination rate: 26%) were weighed out so that the NCO/OH ratio was 1.00. Furthermore, butyl acetate was added so that the solid content was 50 mass%, and the mixture was stirred with a propeller blade at 600 rpm for 10 minutes to obtain a blended composition.

[Preparation Example 2]
The blocked polyisocyanate component obtained in the synthesis example, a fluorine polyol (product name: Zeffle GK-570, manufactured by Daikin Industries, Ltd., solid content: 65 mass%, hydroxyl value: 63 mg KOH/g, fluorination rate: 26%), and an acrylic polyol (product name: Setalux 1152 SS-60, manufactured by Allnex, solid content: 60 mass%, hydroxyl value of resin component: 138.6 mg KOH/g, fluorination rate: 0%) were weighed out so that the NCO/OH was 1.00. Furthermore, butyl acetate was added so that the solid content was 50 mass%, and the mixture was stirred with a propeller blade at 600 rpm for 10 minutes to obtain a blended composition.

[Preparation Example 3]
The blocked polyisocyanate component obtained in the synthesis example and a fluorine polyol (product name: Zeffle GK-570, manufactured by Daikin Industries, Ltd., solid content: 65 mass%, hydroxyl value: 63 mgKOH/g, fluorination rate: 26%) were weighed out so that the NCO/OH ratio was 0.75. Furthermore, butyl acetate was added so that the solid content was 50 mass%, and the mixture was stirred with a propeller blade at 600 rpm for 10 minutes to obtain a blended composition.

[Preparation Example 4]
The blocked polyisocyanate component obtained in the synthesis example and a fluorine polyol (product name: Zeffle GK-570, manufactured by Daikin Industries, Ltd., solid content: 65 mass%, hydroxyl value: 63 mgKOH/g, fluorination rate: 26%) were weighed out so that the NCO/OH ratio was 0.50. Furthermore, butyl acetate was added so that the solid content was 50 mass%, and the mixture was stirred with a propeller blade at 600 rpm for 10 minutes to obtain a blended composition.

[Preparation Example 5]
A blended composition was prepared in the same manner as in Preparation Example 1, except that the solvent was changed to dipropylene glycol dimethyl ether (DPDM).

[Preparation Example 6]
A blended composition was prepared in the same manner as in Preparation Example 1, except that the solvent was changed to dipropylene glycol monomethyl ether (DPM).

<Evaluation method>
[Evaluation 1: Compatibility with polyol]
The appearance of the blended compositions prepared in Preparation Examples was visually observed and evaluated. In addition, the compositions were coated to a film thickness of 15 μm after drying, baked at 120° C. for 15 minutes, and then cooled to 23° C., after which the appearance was visually observed and evaluated.

(Evaluation Criteria)
Compatibility in the formulation composition: ◯: No clouding of the paint △: The paint is uniform and cloudy ×: The paint is separated Compatibility in the coating film: ◯: No clouding of the coating film △: The coating film is uniformly cloudy ×: The coating film is not uniform

[Evaluation 2: Curability]
The blended composition prepared in Preparation Example was applied to a PP plate so that the dry film thickness was 40 μm, and baked at 120° C. for 20 minutes. After drying, the coating film was peeled off and its mass was measured. This coating film (film) was immersed in acetone at 23° C. for 24 hours. This coating film was dried at 105° C. for 60 minutes, and its mass was measured. Curability was evaluated by the ratio of the mass after immersion to the mass before immersion (gel fraction: %).

(Evaluation Criteria)
○: Gel fraction 80% or more △: Gel fraction 50% or more and less than 80% ×: Gel fraction less than 50%

[Evaluation 3: Crosslink density]
The period during the coating film curing process was measured using a rigid pendulum type viscoelasticity measuring instrument (RPT-3000W manufactured by A & D Co., Ltd.) with pendulums FRB-100 and Edge RBE160. The coating film was prepared by painting on a SUS plate so that the dry film thickness was 30 μm. The temperature was raised to 140° C. at 10° C./min, and the period was measured while baking at 140° C. for 40 minutes, and the degree of crosslinking of the coating film was expressed as the rate of decrease in the period. The rate of decrease in the period is expressed as (period before curing-period after curing)/period before curing, and is expressed as %). The greater the rate of decrease in the period, the higher the degree of crosslinking and the better the curability.

(Evaluation Criteria)
○: Periodic drop rate is 60% or more △: Periodic drop rate is 50% or more and less than 60% ×: Periodic drop rate is less than 50%

[Evaluation 4: Blocking resistance]
The blocking resistance was evaluated by a method according to JIS K5600-3-5.
A 50 μm-thick PET film coated to a dry thickness of 15 μm was baked at 110° C. for 10 minutes, then left to stand at 23° C. for 24 hours and allowed to cool. The coated film was cut to 40 mm×40 mm, and the coated and uncoated surfaces of the two films were placed on top of each other, and a 40 mm diameter weight (500 g) with a smooth bottom was placed on top of them. The film was placed in a 40° C./60% oven, and after 72 hours, the film was left to stand at 23° C. for 24 hours and allowed to cool. The coated film was peeled off, and the remaining marks were visually observed to evaluate the blocking resistance.

(Evaluation Criteria)
◯: No traces of paint film remain △: Less than 30% of the paint film remains on the unpainted surface ×: More than 30% of the paint film remains on the unpainted surface

[Evaluation 5: Solvent resistance]
The coating was applied to a glass plate so that the dry thickness was 40 μm, baked at 140° C. for 30 minutes, and then allowed to stand at 23° C. for 24 hours and then allowed to cool. Xylene was spotted on the coating film at a diameter of 1 cm, and a cover glass was placed on top of the spot and allowed to stand at 23° C. for 30 minutes. The xylene was then wiped off, and the appearance of the coating film was visually observed to evaluate the solvent resistance.

(Evaluation Criteria)
○: Almost no deterioration was observed. △: Streaks were observed in some of the rubbed areas. ×: Scratches or thinning or dissolution was observed in the rubbed areas.

<Synthesis Example 1-1>
(Synthesis of polyisocyanate component P-1)
A four-neck flask equipped with a stirrer, a thermometer, a reflux condenser, a nitrogen blowing tube, and a dropping funnel was conditioned with nitrogen, 1000 g of HDI was charged, and 85.0 g of polypropylene glycol (product name: Sannix PP-400, number average molecular weight: 400, number of hydroxyl groups: 2, manufactured by Sanyo Chemical Industries, Ltd.) was charged, and the temperature inside the reactor was maintained at 100°C under stirring to allow the urethane reaction to proceed. Thereafter, tetramethylammonium caprylate, which is an isocyanurate reaction catalyst, was added, and when the yield reached 60%, phosphoric acid was added to stop the reaction. After filtering the reaction liquid, unreacted HDI was removed using a thin-film evaporator to obtain polyisocyanate component P-1. The viscosity of the obtained polyisocyanate component P-1 at 25°C was 8,000 mPa·s, and the isocyanate group content was 16.7% by mass.

<Synthesis Example 1-2>
(Synthesis of polyisocyanate component P-2)
In a reaction vessel similar to that of Synthesis Example 1-1, 600 g of HDI and 60 g of polycaprolactone-based polyester triol (product name: PLACCEL 303, number average molecular weight: 300, number of hydroxyl groups: 3, manufactured by Daicel Corporation) were charged, and the temperature inside the reactor was maintained at 90° C. for 1 hour under stirring to carry out a pre-reaction. Thereafter, the temperature inside the reactor was maintained at 80° C., and tetramethylammonium caprylate, which is an isocyanurate reaction catalyst, was added, and when the yield reached 48%, phosphoric acid was added to stop the reaction. After filtering the reaction liquid, unreacted HDI was removed using a thin-film evaporator to obtain polyisocyanate component P-2. The viscosity of the obtained polyisocyanate component P-2 at 25° C. was 20,000 mPa·s, and the isocyanate group content was 18.3% by mass.

<Synthesis Example 1-3>
(Synthesis of polyisocyanate component P-3)
In a reaction vessel similar to that of Synthesis Example 1-1, 600 g of HDI and 24 g of 1,3-butanediol (1,3-BG) were charged, and the temperature inside the reactor was maintained at 90° C. for 1 hour under stirring to carry out a urethane reaction. Thereafter, the temperature inside the reactor was maintained at 80° C., and tetramethylammonium caprylate, an isocyanurate catalyst, was added, and when the yield reached 55%, phosphoric acid was added to stop the reaction. After filtering the reaction liquid, unreacted HDI was removed using a thin-film evaporator to obtain polyisocyanate P-3. The viscosity of the obtained polyisocyanate component P-3 at 25° C. was 14,000 mPa·s, and the isocyanate group content was 19.1% by mass.

<Synthesis Example 1-4>
(Synthesis of polyisocyanate component P-4)
In a reaction vessel similar to that of Synthesis Example 1-1, 600 g of HDI and 10.8 g of 1,3-butanediol (1,3-BG) were charged, and the temperature inside the reactor was maintained at 90° C. for 1 hour under stirring to carry out a urethane reaction. Thereafter, the temperature inside the reactor was maintained at 80° C., and 0.03 parts of tetramethylammonium caprylate was added as an isocyanurate catalyst, and when the yield reached 55%, phosphoric acid was added to stop the reaction. After filtering the reaction liquid, unreacted HDI was removed using a thin-film evaporator to obtain polyisocyanate component P-4. The viscosity of the obtained polyisocyanate component P-4 at 25° C. was 20,400 mPa·s, and the isocyanate group content was 19.3% by mass.

<Synthesis Example 1-5>
(Synthesis of polyisocyanate component P-5)
In a reaction vessel similar to that of Synthesis Example 1-1, 600 g of HDI and 14 g of 1,3-butanediol (1,3-BG) were charged, and the temperature inside the reactor was maintained at 90° C. for 1 hour under stirring to carry out a urethane reaction. Thereafter, the temperature inside the reactor was maintained at 80° C., and tetramethylammonium caprylate, an isocyanurate catalyst, was added, and when the yield reached 37%, phosphoric acid was added to stop the reaction. After filtering the reaction liquid, unreacted HDI was removed using a thin-film evaporator to obtain polyisocyanate P-5. The viscosity of the obtained polyisocyanate component P-5 at 25° C. was 2,100 mPa·s, and the isocyanate group content was 21.4% by mass.

<Synthesis Examples 2-1 to 2-5>
(Synthesis of Blocked Polyisocyanate Components B-1 to B-5)
In a reaction vessel similar to that of Synthesis Example 1-1, polyisocyanate components P-1 to P-5 synthesized in Synthesis Examples 1-1 to 1-5 were each kept at 80°C, and 3,5-dimethylpyrazole (3,5-DMP) was added in an amount of 1.05 times by mole relative to the isocyanate of each polyisocyanate component, followed by stirring for 30 minutes. After confirming that the characteristic absorption of the isocyanate group had disappeared by infrared spectroscopy, butyl acetate was added to a solid content of 70 mass% and stirred to obtain blocked polyisocyanate components B-1 to B-5. The physical properties of the obtained blocked polyisocyanate components B-1 to B-5 are shown in Table 1.

<Synthesis Examples 2-6 and 2-7>
Blocked polyisocyanate components B-6 and B-7 were obtained by synthesizing in the same manner as in Synthesis Example 2-1, except that 3,5-dimethylpyrazole (3,5-DMP) was added in an amount of 0.70 times the molar amount of the isocyanate in polyisocyanate components P-2 and P-3. The physical properties of the obtained blocked polyisocyanate components B-6 and B-7 are shown in Table 1.

<Examples 1 to 6>
Using the blocked polyisocyanate components B-1 to 4, 6 and 7 synthesized in Synthesis Examples 1-1 to 4, 6 and 7, coating compositions were prepared according to the formulation described in Preparation Example 1. These coating compositions were evaluated according to the methods of Evaluation 1 to 5. The results are shown in Table 1.

<Examples 7 to 9>
Using the blocked polyisocyanate components B-1 to B-3 synthesized in Synthesis Examples 1 to 3, coating compositions were prepared according to the formulation described in Preparation Example 2. These coating compositions were evaluated according to the evaluation methods 1 to 5. The results are shown in Table 1.

<Examples 10 to 12>
Using the blocked polyisocyanate components B-1 to B-3 synthesized in Synthesis Examples 1 to 3, coating compositions were prepared according to the formulation described in Preparation Example 3. These coating compositions were evaluated according to the evaluation methods 1 to 5. The results are shown in Table 1.

<Examples 13 to 15>
Using the blocked polyisocyanate components B-1 to B-3 synthesized in Synthesis Examples 1 to 3, coating compositions were prepared according to the formulation described in Preparation Example 4. These coating compositions were evaluated according to the methods of Evaluation 1 to 5. The results are shown in Table 1.

<Example 16>
Using the blocked polyisocyanate components B-1 to B-3 synthesized in Synthesis Example 2, coating compositions were prepared according to the formulation described in Preparation Example 5. These coating compositions were evaluated according to the evaluation methods 1 to 5. The results are shown in Table 1.

<Examples 17 to 19>
Using the blocked polyisocyanate components B-1 to B-3 synthesized in Synthesis Examples 1 to 3, coating compositions were prepared according to the formulation described in Preparation Example 6. These coating compositions were evaluated according to the methods of Evaluation 1 to 5. The results are shown in Table 1.

<Comparative Examples 1 to 3>
Using the blocked polyisocyanate component B-5 synthesized in Synthesis Example 5, a coating composition was prepared according to the formulation described in Preparation Examples 1 to 3. This coating composition was evaluated according to the evaluation methods 1 to 5. The results are shown in Table 1.

The blended composition or coating composition of this embodiment is compatible with the blocked polyisocyanate component and polyol, and when this blended composition is used to form a coating film, it is possible to provide an article having high crosslink density, excellent blocking resistance, and excellent solvent resistance of the cured coating film.

Claims (11)

A blended composition containing a blocked polyisocyanate component and a polyol,
The blocked polyisocyanate component is a reaction product of a diisocyanate, one or more alcohols, and a thermally dissociable blocking agent;
the diisocyanate is one or more diisocyanates selected from aliphatic diisocyanates and alicyclic diisocyanates, the blocked polyisocyanate component has a molar ratio of [isocyanurate/(isocyanurate group+allophanate group)] of 0.1 or more and 0.9 or less, and the mass fraction of blocked isocyanates having a number average molecular weight of 1,000 or less contained in the blocked polyisocyanate component is 5.0% by mass or more and 50.0% by mass or less,
The blocked polyisocyanate component has a molar ratio (NCO/OH) of the isocyanate group bonded to the thermally dissociable blocking agent to the hydroxyl group in the polyol of 0.05/1.0 or more and 1.2/1.0 or less. The blended composition according to claim 1, wherein the alcohol has a number of hydroxyl groups of 1.5 or more and 6.0 or less, and a number average molecular weight of 70 or more and 1,000 or less. The compounded composition according to claim 1 or 2, wherein the number average molecular weight of the blocked polyisocyanate component is 900 or more and 3,000 or less. The compounded composition according to claim 1 or 2, wherein the average number of isocyanate groups bonded to the thermally dissociable blocking agent per molecule is 2.8 or more and 6.2 or less. The compounded composition according to claim 1 or 2, wherein the molar ratio of urethane groups to isocyanurate groups in the blocked polyisocyanate component is 0.3 or less. The compounded composition according to claim 1 or 2, wherein the thermally dissociable blocking agent is at least one selected from the group consisting of oxime compounds, acid amide compounds, amine compounds, active methylene compounds, and pyrazole compounds. The compounded composition according to claim 1 or 2, wherein the thermally dissociable blocking agent is a pyrazole compound. The compounded composition according to claim 1 or 2, wherein the polyol contains a fluoropolyol, the fluorine content of the fluoropolyol is 2.0% by mass or more and 50.0% by mass or less, and the hydroxyl value in the fluoropolyol is 30 mgKOH/g or more and 200 mgKOH/g or less. The blended composition according to claim 1 or 2, wherein the polyol contains 10% by mass or more of a fluorine polyol. A coating composition comprising the blend composition according to claim 1 or 2. A coating film formed by curing the coating composition according to claim 10.