WO2018235896A1 - Blocked isocyanate composition, one-pack type coating composition and coating film - Google Patents

Abstract

This blocked isocyanate composition contains a blocked isocyanate compound that is obtained from a triisocyanate compound represented by general formula (I) and at least two blocking agents. (In general formula (I), each one of the plurality of Y1 moieties independently represents a single bond or a divalent hydrocarbon group having 1-20 carbon atoms, which may contain at least one structure selected from the group consisting of an ester structure and an ether structure; the plurality of Y1 moieties may be the same as or different from each other; and R1 represents a hydrogen atom or a monovalent hydrocarbon group having 1-12 carbon atoms.)

Description

Blocked isocyanate composition, one-pack coating composition and coating film

The present invention relates to a blocked isocyanate composition, a one-pack coating composition and a coating film.
Priority is claimed on Japanese Patent Application No. 2017-123599, filed Jun. 23, 2017, the content of which is incorporated herein by reference.

Traditionally, urethane coatings formed from polyurethane coatings have very good flexibility, chemical resistance and stain resistance. In particular, a coating film using a non-yellowing type polyisocyanate composition obtained from an aliphatic diisocyanate represented by hexamethylene diisocyanate (hereinafter sometimes referred to as "HDI") as a curing agent is more weather resistant. Even better, its demand is increasing.

BACKGROUND ART In recent years, technological development for reducing the viscosity of a polyisocyanate composition used as a curing agent has been actively carried out due to the increase in global environmental protection. This is because the use amount of the organic solvent used in the coating composition can be reduced by lowering the viscosity of the polyisocyanate composition (see, for example, Patent Documents 1 and 2). Patent documents 3 to 5 disclose low viscosity triisocyanate compounds, and the use of these triisocyanate compounds in a coating composition can reduce the amount of organic solvent used.

The polyisocyanate composition forms a cross-linked coating at normal temperature with a polyol. Polyisocyanate compositions are widely used for baking paints as heat curing type curing agents together with melamine type curing agents. In recent years, it has been pointed out that formalin is generated when a melamine-based curing agent is used. Therefore, a polyisocyanate (blocked polyisocyanate) composition blocked by a blocking agent that dissociates the isocyanate group in the polyisocyanate composition by heating is attracting attention from the viewpoint of global environment, safety, hygiene, and the like.

As a block polyisocyanate composition capable of forming a crosslinked coating film at a relatively low temperature, a block polyisocyanate (pyrazole block polyisocyanate) composition using a pyrazole compound as a blocking agent (see, for example, Patent Document 6) Is disclosed. Further, for example, Patent Literatures 7 and 8 disclose triisocyanate blocked by using a pyrazole compound as a blocking agent (hereinafter sometimes referred to as "blocked triisocyanate"). Further, for example, Patent Document 9 has a block polyisocyanate composition containing one or more selected from the group consisting of aliphatic isocyanate and alicyclic isocyanate blocked by using a pyrazole compound and an oxime compound as a blocking agent. Objects are disclosed.

Japanese Patent Application Laid-Open No. 05-222007 Patent 3055197 gazette Japanese Patent Publication No. 63-015264 Japanese Patent Application Laid-Open No. 53-135931 Japanese Patent Application Laid-Open No. 60-044561 European Patent Application Publication No. 159117 Patent No. 4671668 Unexamined-Japanese-Patent No. 2005-154778 JP 2011-236388 A

In a block polyisocyanate composition, coexistence with low-viscosity-izing and the crosslinked film formation ability in low temperature is calculated | required.
However, although the block polyisocyanate composition described in Patent Documents 6 and 9 cures at a relatively low temperature, it is insufficient in view of viscosity reduction.
Moreover, although the blocked triisocyanate described in Patent Documents 7 and 8 cures at a relatively low temperature, it can not be used in a liquid paint because the blocked triisocyanate crystallizes.

The present invention has been made in view of the above circumstances, and provides a blocked isocyanate composition having a low viscosity, and low crystallinity, low temperature curability, and storage stability of a paint. The present invention also provides a one-component coating composition and a coating film using the above-mentioned blocked isocyanate composition.

That is, the present invention includes the following aspects.
[1] A blocked isocyanate composition comprising a blocked isocyanate compound obtained from a triisocyanate compound represented by the following general formula (I) and at least two blocking agents.

In the general formula (I), a plurality of Y ^{1 s} each independently represent a single bond or a divalent C 1 -C 20 divalent group which may contain at least one selected from the group consisting of an ester structure and an ether structure It is a hydrocarbon group. The plurality of Y ¹ may be identical to or different from each other. R ¹ is a hydrogen atom or a monovalent hydrocarbon group having 1 to 12 carbon atoms.
[2] The blocked isocyanate composition according to [1], wherein the at least two blocking agents comprise at least one member selected from the group consisting of an amine compound and an active methylene compound, and a pyrazole compound.
[3] The block according to the above [1] or [2], wherein the proportion of isocyanate groups blocked by the pyrazole compound among the isocyanate groups blocked by the blocking agent is 20 mol% to 80 mol% Isocyanate composition.
[4] A one-component paint composition comprising the blocked isocyanate composition according to any one of the above [1] to [3] and a polyol.
[5] A coating film obtained by curing the one-component coating composition according to the above [4].

According to the above aspect, it is possible to provide a blocked isocyanate composition which has a low viscosity and is low in crystallinity, low temperature curability, and storage stability of a paint. Moreover, a one-component coating composition and a coating film can be provided by using the blocked isocyanate composition.

Hereinafter, modes for carrying out the present invention (hereinafter, simply referred to as "the present embodiment") will be described in detail. The following present embodiment is an example for describing the present invention, and is not intended to limit the present invention to the following contents. The present invention can be appropriately modified and implemented within the scope of the gist of the present invention.
In the present specification, “polyisocyanate” means a polymer in which a plurality of monomers having one or more isocyanate groups (—NCO) are bonded.
Also, as used herein, "polyol" means a compound having two or more hydroxy groups (-OH).
In the present specification, unless otherwise specified, "(meth) acrylic" includes methacryl and acrylic. Also, "(meth) acrylate" is intended to encompass methacrylate and acrylate.

«Blocked isocyanate composition»
The blocked isocyanate composition according to one embodiment of the present invention comprises at least two types of blocks, a triisocyanate compound represented by the following general formula (I) (hereinafter sometimes referred to as "triisocyanate compound (I)") And a blocked isocyanate compound obtained from the agent.

In the general formula (I), a plurality of Y ^{1 s} each independently represent a single bond or a divalent C 1 -C 20 divalent group which may contain at least one selected from the group consisting of an ester structure and an ether structure It is a hydrocarbon group. The plurality of Y ¹ may be identical to or different from each other. R ¹ is a hydrogen atom or a monovalent hydrocarbon group having 1 to 12 carbon atoms.

The blocked isocyanate composition of the present embodiment has a low viscosity by containing the blocked isocyanate compound obtained from the triisocyanate compound (I) and at least two kinds of blocking agents, and has low crystallinity and low temperature curing. And excellent in the storage stability of the paint.

<Blocked isocyanate compound>
The blocked isocyanate compound contained in the blocked isocyanate composition of the present embodiment is obtained from the above triisocyanate compound (I) and at least two kinds of blocking agents.

[Triisocyanate Compound (I)]
(Y ¹ )
In General Formula (I), a plurality of Y ^{1 s} each independently represent a single bond, or a divalent group having 1 to 20 carbon atoms which may contain at least one selected from the group consisting of an ester structure and an ether structure Is a hydrocarbon group of A plurality of Y ^{1 s} may be identical to or different from each other.

The divalent hydrocarbon group having 1 to 20 carbon atoms may be an aliphatic group or an aromatic group. The aliphatic group may be linear, branched or cyclic.
As said linear or branched aliphatic group, an alkanediyl group (alkylene group), an alkylidene group etc. are mentioned, for example.
As said cyclic aliphatic group, a cycloalkylene group etc. are mentioned, for example.
As said aromatic group, arylene groups, such as a phenylene group, are mentioned, for example.
Among these, as the above-mentioned hydrocarbon group, an alkylene group having 1 to 6 carbon atoms is preferable.

In addition, examples of the divalent hydrocarbon group having 1 to 20 carbon atoms which may contain at least one selected from the group consisting of the ester structure and the ether structure in Y ¹ include, for example, a group represented by the following general formula (II) Groups are mentioned.
_{^{* 1 - (CH 2) n1}} -X- (CH 2) n2 - * 2 (II)

In the general formula (II), * ¹ represents a bond with C in the above general formula (I), and * ² represents a bond with NCO in the general formula (I). Further, n1 and n2 are each independently an integer of 0 to 20 satisfying 1 ≦ n1 + n2 ≦ 20. That is, both n1 and n2 can not be 0, and it is preferable that n2 connected to NCO be 1 or more.
Among them, n1 and n2 are each independently more preferably an integer of 0 to 4, and still more preferably an integer of 0 to 2.
As a combination of n1 and n2, for example, a combination of n1 = 0 and n2 = 2 and a combination of n1 = 2 and n2 = 2 are preferable.

In the above general formula (II), X is an ester group or an ether group. Among them, X is preferably an ester group because the reaction rate is increased.

In addition, when at least ^one of the plurality of Y ¹ has at least one member of the group consisting of an aliphatic group and an aromatic group, the blocked isocyanate composition of the present embodiment can be made to have a lower viscosity, The blocked isocyanate composition of the embodiment can be used as a curing agent for a paint composition to make the resulting coating film more weather resistant.

Moreover, when at least ^one of the plurality of Y ¹ has an ester structure, the heat resistance of the blocked isocyanate composition of the present embodiment can be further improved, and the isocyanate when used as a curing agent for the coating composition The reactivity of the group can be further enhanced.

Also preferably, at least one of Y ¹ to more exist if consisting only of a hydrocarbon group, more preferably, when all of the Y ¹ there are a plurality of consists only hydrocarbon group, the present embodiment The hydrolysis resistance of the blocked isocyanate composition can be further improved.

(R ¹ )
R ¹ is a hydrogen atom or a monovalent hydrocarbon group having 1 to 12 carbon atoms. The hydrocarbon group in R ¹ is not particularly limited, and examples thereof include an alkyl group, an alkenyl group, and an alkynyl group. Among them, a hydrogen atom is preferable as R ¹ .

In the present embodiment, when at least one of a plurality of Y ¹ has one or more of the group consisting of an aliphatic group and an aromatic group, it is specifically preferable as a triisocyanate compound (I), for example, 4-isocyanatomethyl-1,8-octamethylene diisocyanate (hereinafter referred to as "NTI", molecular weight 251) disclosed in JP-B-63-15264 (patent document 3), JP-A-57-198760 1, 3, 6-hexamethylene triisocyanate (hereinafter referred to as "HTI", molecular weight 209) disclosed in Japanese Patent Application Publication No. 4-1033 (reference document 2) disclosed in Bis (2-isocyanatoethyl) 2-isocyanatoflate (hereinafter referred to as "GTI", molecular weight 311), JP-A-53- And lysine triisocyanate (hereinafter referred to as "LTI", molecular weight 267) disclosed in JP-A-135931 (Reference 3) and the like.

Among them, from the viewpoint of being able to further improve the reactivity of the isocyanate group, when at least one of the plurality of Y ¹ has one or more of the group consisting of an aliphatic group and an aromatic group, as a triisocyanate compound (I) Is preferably NTI, GTI or LTI, more preferably NTI or LTI, still more preferably LTI.

In the present embodiment, when at least one of a plurality of Y ¹ has an ester structure, it is specifically preferable as a triisocyanate compound (I), for example, JP-B 4-1033 (reference 2) And the LTI (molecular weight 267) disclosed in JP-A-53-135931 (Reference 3).

In the present embodiment, when at least one of a plurality of Y ¹ is composed only of a hydrocarbon group, it is specifically preferable as a triisocyanate compound (I), for example, JP-B-63-15264 (Patent The NTI (molecular weight 251) disclosed in the literature 3), the HTI (molecular weight 209) disclosed in JP-A-57-198760 (reference 1), and the like can be mentioned.

The triisocyanate compound can be obtained, for example, by isocyanation of an amine such as an amino acid derivative, an ether amine and an alkyltriamine.

Examples of the amino acid derivative include 2,5-diaminovaleric acid, 2,6-diaminohexanoic acid, aspartic acid, glutamic acid and the like. Since these amino acid derivatives are diamine monocarboxylic acid or monoamine dicarboxylic acid, the carboxyl group can be esterified with an alkanolamine such as ethanolamine to give a triamine having an ester group. The triamine having an ester group obtained can be made into a triisocyanate compound containing an ester structure by phosgenation of an amine or the like.

As said ether amine, the brand name "D403" of Mitsui Chemicals Fine Inc. which is polyoxyalkylene triamine etc. are mentioned, for example. These ether amines are triamines and can be converted to triisocyanate compounds containing an ether structure by phosgenation of amines or the like.

Examples of the alkyltriamine include triisocyanatononane (4-aminomethyl-1,8-octanediamine) and the like. These alkyltriamines are triamines and can be converted to triisocyanate compounds containing only hydrocarbons by phosgenation of amines or the like.

In the present embodiment, the lower limit value of the molecular weight of the triisocyanate compound is preferably 139 or more, more preferably 150 or more, still more preferably 180 or more, and particularly preferably 200 or more.
On the other hand, the upper limit value of the molecular weight of the triisocyanate compound is preferably 1000 or less, more preferably 800 or less, still more preferably 600 or less, and particularly preferably 400 or less.
That is, the molecular weight of the triisocyanate compound is preferably 139 or more and 1000 or less, more preferably 150 or more and 800 or less, still more preferably 180 or more and 600 or less, and particularly preferably 200 or more and 400 or less. preferable.
When the molecular weight of the triisocyanate compound is at least the lower limit, crystallinity can be further suppressed, and when the molecular weight is at the upper limit or less, viscosity reduction can be further achieved.

[Block agent]
The blocked isocyanate compound contained in the blocked isocyanate composition of the present embodiment is a compound in which the isocyanate group of the triisocyanate compound is protected by two or more block agents.
Examples of the blocking agent include (1) pyrazole compounds, (2) amine compounds, (3) active methylene compounds, (4) oxime compounds, (5) alcohol compounds, (6) alkylphenol compounds, (7) Phenolic compounds, (8) mercaptan compounds, (9) acid amide compounds, (10) acid imide compounds, (11) imidazole compounds, (12) urea compounds, (13) imine compounds , (14) bisulfite, (15) triazole compounds and the like. More specific examples of the blocking agent include those shown below.

(1) Pyrazole compounds: pyrazole, 3-methylpyrazole, 3,5-dimethylpyrazole and the like.
(2) Amine compounds: diphenylamine, aniline, carbazole, di-n-propylamine, diisopropylamine, isopropylethylamine, tert-butylbenzylamine and the like.
(3) Active methylene compounds: dimethyl malonate, diethyl malonate, diisopropyl malonate, di-tert-butyl malonate, methyl acetoacetate, ethyl acetoacetate, acetylacetone and the like.
(4) Oxime-type compounds: formaldoxime, acetoaldoxime, acetoxime, methyl ethyl ketoxime, cyclohexanone oxime and the like.

(5) Alcohol compounds: Alcohols such as methanol, ethanol, 2-propanol, n-butanol, sec-butanol, 2-ethyl-1-hexanol, 2-methoxyethanol, 2-ethoxethanol and 2-butoxyethanol .
(6) Alkylphenol-based compounds: mono- and dialkylphenols having an alkyl group having 4 or more carbon atoms as a substituent. Specific examples of the alkylphenol compound include n-propylphenol, iso-propylphenol, n-butylphenol, sec-butylphenol, t-butylphenol, n-hexylphenol, 2-ethylhexylphenol, n-octylphenol and n-nonylphenol Etc .; di-n-propylphenol, diisopropylphenol, isopropylcresol, di-n-butylphenol, di-t-butylphenol, di-sec-butylphenol, di-n-octylphenol, di-2-ethylhexylphenol Dialkylphenols such as di-n-nonylphenol.
(7) Phenolic compounds: phenol, cresol, ethylphenol, styrenated phenol, hydroxybenzoic acid ester and the like.

(8) Mercaptan compounds: butyl mercaptan, dodecyl mercaptan and the like.
(9) Acid amide compounds: Acetoanilide, acetic acid amide, ε-caprolactam, δ-valerolactam, γ-butyrolactam and the like.
(10) Acid imide compounds: Succinimide, maleic imide and the like.
(11) Imidazole compounds: imidazole, 2-methylimidazole and the like.
(12) Urea compounds: urea, thiourea, ethylene urea and the like.
(13) Imine compounds: ethyleneimine, polyethyleneimine and the like.
(14) Bisulfite: sodium bisulfite and the like.
(15) Triazole compounds: 3,5-dimethyl-1,2,4-triazole and the like.

The at least two blocking agents preferably include a pyrazole compound, and more preferably include at least one member selected from the group consisting of an amine compound, an active methylene compound and an oxime compound, together with the pyrazole compound. . From the viewpoint of low temperature curability, the at least two blocking agents more preferably contain an amine compound or an active methylene compound together with the pyrazole compound.

As the pyrazole compound, the effects (eg, low viscosity, low crystallinity, low temperature curability, etc.) exhibited by the blocked isocyanate composition of the present embodiment are realized, and from the viewpoint of ease of availability, 3,5- Dimethylpyrazole is preferred.
The amine compound is preferably diisopropylamine or tert-butylbenzylamine.
As the active methylene compound, diethyl malonate or ethyl acetoacetate is preferred.
As said oxime type compound, methyl ethyl ketoxime is preferable.

<Method for producing blocked isocyanate compound>
The blocking reaction of the triisocyanate compound with the blocking agent can be carried out with or without the presence of a solvent to obtain a blocked isocyanate compound.

When using a solvent, it is necessary to use a solvent inert to the isocyanate group. Examples of the solvent include ketone solvents such as acetone and methyl ethyl ketone, and ester solvents such as ethyl acetate and butyl acetate.
In the blocking reaction, an organic metal salt such as tin, zinc or lead, a tertiary amine compound, or an alcoholate of an alkali metal such as sodium may be used as a catalyst.

The blocking reaction can generally be carried out at -20 ° C or more and 150 ° C or less, preferably 30 ° C or more and 100 ° C or less. When the temperature of the block reaction is equal to or higher than the above lower limit value, the reaction rate can be further increased, and by being equal to or lower than the above upper limit value, side reactions can be further suppressed.

In the blocked isocyanate composition of the present embodiment, the proportion of isocyanate groups blocked by the pyrazole compound among the isocyanate groups blocked by the blocking agent is 80 mol% or less from the viewpoint of low crystallinity of the blocked isocyanate composition Is preferably, and more preferably 70 mol% or less. In addition, from the viewpoint of low temperature curability, 20 mol% or more is preferable, and 30 mol% or more is more preferable.

«Blocked isocyanate composition of polyisocyanate»
The blocked isocyanate composition of the polyisocyanate according to one embodiment of the present invention has a structure represented by the following general formula (III), an isocyanurate structure, a burette structure, a uretdione structure, an iminooxadiazine dione structure, a urethane structure and an allophanate It includes a blocked isocyanate compound obtained from a polyisocyanate compound containing at least one member selected from the group consisting of structures, and a blocking agent.

In the general formula (III), Y ¹ and R ¹ are as described in the general formula (I).
The blocked isocyanate composition of the polyisocyanate of the present embodiment is further excellent in low temperature curability.

«Hydrophilic block isocyanate composition»
The hydrophilic block isocyanate composition according to one embodiment of the present invention is obtained from the block isocyanate compound in the above-mentioned block isocyanate composition and a compound containing an active hydrogen group and a hydrophilic group (hydrophilic group-containing compound) It contains a hydrophilic block isocyanate compound.
Since the hydrophilic block isocyanate composition of the present embodiment is excellent in water dispersibility, it can be easily dispersed in a hydrophilic solvent.

<Hydrophilic block isocyanate compound>
By reacting the isocyanate group of the blocked isocyanate compound in the above-described blocked isocyanate composition with the hydrophilic group-containing compound, a hydrophilic blocked isocyanate compound to which a hydrophilic group is added can be obtained.
Although it does not specifically limit as a hydrophilic group containing compound which can be reacted with an isocyanate group, For example, the compound containing hydrophilic groups, such as nonionicity, cationic property, anionic property, is mentioned.

[Nonionic hydrophilic group]
Although it does not specifically limit as a compound containing a nonionic hydrophilic group, For example, the compound etc. which added ethylene oxide to the hydroxyl group of alcohol, such as methanol, ethanol, butanol, ethylene glycol, diethylene glycol, etc. are mentioned. These compounds have active hydrogen which reacts with isocyanate groups.
Among them, since the water dispersibility of the hydrophilic polyisocyanate composition can be improved with a small amount used, a monoalcohol having ethylene oxide is preferable as the compound containing a nonionic hydrophilic group.

As a content number of ethylene oxide in the compound containing a nonionic hydrophilic group, 4 or more and 30 or less are preferable, and 4 or more and 20 or less are more preferable.
When the number of ethylene oxide contained is equal to or more than the above lower limit value, it tends to be easy to secure water-ization. In addition, when the number of ethylene oxide contained is less than or equal to the above upper limit value, the precipitate of the hydrophilic block isocyanate composition tends to be less likely to be generated during low temperature storage.

[Cationic hydrophilic group]
When a cationic hydrophilic group is introduced into the above-mentioned blocked isocyanate compound to obtain a hydrophilic blocked isocyanate compound, for example, a compound having both a cationic hydrophilic group and a functional group having hydrogen which reacts with an isocyanate group is used. A method to be used, a method of adding a functional group such as a glycidyl group to an isocyanate group in advance, and then allowing this functional group to react with a specific compound such as sulfide or phosphine may be mentioned.
Among them, when a cationic hydrophilic group is introduced into the above-mentioned blocked isocyanate compound to obtain a hydrophilic blocked isocyanate compound, the reaction is easy, and therefore, it has a cationic hydrophilic group and hydrogen which reacts with the isocyanate group. The method of utilizing the compound which has a functional group together is preferable.

Although it does not specifically limit as a functional group which has the hydrogen which reacts with the said isocyanate group, For example, a hydroxyl group, a thiol group, etc. are mentioned.
The compound having both the cationic hydrophilic group and a functional group having hydrogen which reacts with an isocyanate group is not particularly limited, and examples thereof include dimethylethanolamine, diethylethanolamine, diethanolamine, methyldiethanolamine, N, N-dimethyl Aminohexanol, N, N-dimethylaminoethoxyethanol, N, N-dimethylaminoethoxyethoxyethanol, N, N, N'-trimethylaminoethylethanolamine, N-methyl-N- (dimethylaminopropyl) aminoethanol, etc. It can be mentioned.

When the hydrophilic block isocyanate compound has a tertiary amino group as a cationic hydrophilic group, it can be quaternized with dimethyl sulfate, diethyl sulfate or the like.

Moreover, as a cationic hydrophilic group which a hydrophilic block isocyanate compound has, a tertiary amino group is preferable. When the hydrophilic polyisocyanate compound has a tertiary amino group, a compound such as an anionic compound used for neutralization described later tends to be volatilized by heating, and as a result, the water resistance tends to be further improved.

Moreover, introduction of the cationic hydrophilic group to the above-mentioned blocked isocyanate compound can be performed in the presence of a solvent. The solvent preferably does not contain a functional group capable of reacting with an isocyanate group. The solvent is not particularly limited, and examples thereof include ethyl acetate, propylene glycol monomethyl ether acetate, dipropylene glycol dimethyl ether and the like.

When the hydrophilic blocked isocyanate compound has a cationic hydrophilic group, the cationic hydrophilic group is preferably neutralized with a compound having an anionic group.

Although it does not specifically limit as said anion group, For example, a carboxyl group, a sulfonic acid group, a phosphoric acid group, a halogen group, a sulfuric acid group etc. are mentioned.

The compound having one carboxyl group as an anion group is not particularly limited, and examples thereof include formic acid, acetic acid, propionic acid, butyric acid and lactic acid.
Moreover, as a compound which has a sulfonic acid group as an anion group, although it does not specifically limit, an ethane sulfonic acid etc. are mentioned, for example.
Moreover, as a compound which has a phosphoric acid group as an anion group, although it does not specifically limit, For example, phosphoric acid, an acidic phosphoric acid ester, etc. are mentioned.
Further, the compound having a halogen group as an anion group is not particularly limited, and examples thereof include hydrochloric acid and the like.
Moreover, it does not specifically limit as a compound which has a sulfate group as an anion group, For example, a sulfuric acid etc. are mentioned.
Among them, as a compound having an anion group, a compound having one carboxyl group is preferable, and acetic acid, propionic acid or butyric acid is more preferable.

[Anionic hydrophilic group]
The anionic hydrophilic group is not particularly limited, and examples thereof include a carboxylic acid group, a sulfonic acid group, a phosphoric acid group, a halogen group and a sulfuric acid group.
The hydrophilic blocked isocyanate compound having an anionic hydrophilic group is, for example, reacting the active hydrogen of a compound having an anionic group and the active hydrogen of the compound having an anionic hydrophilic group with the isocyanate group of the above-described blocked isocyanate compound. Can be obtained by

The compound having active hydrogen and a carboxylic acid group is not particularly limited, and examples thereof include monohydroxy such as 1-hydroxyacetic acid, 3-hydroxypropanoic acid, 12-hydroxy-9-octadecanoic acid, hydroxypivalic acid, and lactic acid. Carboxylic acids include polyhydroxycarboxylic acids such as dimethylolacetic acid, 2,2-dimethylolbutyric acid, 2,2-dimethylolpentanoic acid, dihydroxysuccinic acid, and dimethylolpropionic acid.
Among them, as a compound having active hydrogen and a carboxylic acid group, hydroxypivalic acid or dimethylol propionic acid is preferable.

The compound having active hydrogen and a sulfonic acid group is not particularly limited, and examples thereof include isethionic acid.

When the hydrophilic polyblock isocyanate compound has an anionic hydrophilic group, the anionic hydrophilic group is preferably neutralized with a compound having a cationic group.
The compound having a cationic group is not particularly limited, and examples thereof include amine compounds which are basic substances.

Although it does not specifically limit as said amine compound, For example, ammonia, a water-soluble amino compound, etc. are mentioned.
Examples of water-soluble amino compounds include, but are not limited to, monoethanolamine, ethylamine, dimethylamine, diethylamine, triethylamine, propylamine, dipropylamine, isopropylamine, diisopropylamine, triethanolamine, butylamine, dibutylamine, and the like. Primary or secondary amines such as ethylhexylamine, ethylenediamine, propylenediamine, methylethanolamine, dimethylethanolamine, diethylethanolamine and morpholine; and tertiary amines such as triethylamine and dimethylethanolamine.

«One-component paint composition»
The one-pack type paint composition which concerns on one Embodiment of this invention contains the above-mentioned blocked isocyanate composition and a polyol.
The above-described blocked isocyanate composition can be suitably used as a curing agent or the like of the one-component coating composition of the present embodiment.
Therefore, the one-component coating composition of the present embodiment can improve the weather resistance of the resulting coating film by including the above-described blocked isocyanate composition.

<Polyol>
The one-component coating composition of the present embodiment contains the above-described blocked isocyanate composition and a polyol as a resin component.
Examples of resin components other than polyols include polyamines and polythiols.

Examples of the polyol include polyester polyol, polyether polyol, acrylic polyol, polyolefin polyol, fluorine polyol and the like. Among them, acrylic polyol is preferable as the polyol from the viewpoint of weather resistance, chemical resistance and hardness. Alternatively, as the polyol, polyester polyols are preferable from the viewpoint of mechanical strength and oil resistance.

[Polyester polyol]
The polyester polyol can be obtained, for example, by condensation reaction of a dibasic acid alone or a mixture of two or more with a polyhydric alcohol alone or a mixture of two or more.

Examples of the dibasic acid include carboxylic acids such as succinic acid, adipic acid, dimer acid, maleic anhydride, phthalic anhydride, isophthalic acid, terephthalic acid, 1,4-cyclohexanedicarboxylic acid and the like.

Examples of the polyhydric alcohol include ethylene glycol, propylene glycol, diethylene glycol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, trimethylpentanediol, cyclohexanediol, trimethylolpropane, glycerin and pentaerythritol. And 2-methylolpropanediol, ethoxylated trimethylolpropane and the like.

As a specific production method of the polyester polyol, for example, the condensation reaction can be carried out by mixing the above-mentioned components and heating at about 160 to 220 ° C.
Alternatively, for example, polycaprolactones obtained by ring-opening polymerization of lactones such as ε-caprolactone using polyhydric alcohol can also be used as the polyester polyol.
These polyester polyols can be modified with aromatic diisocyanates, aliphatic diisocyanates, alicyclic diisocyanates, polyisocyanates obtained therefrom, and the like. Among them, from the viewpoint of weatherability, yellowing resistance and the like, it is preferable to modify the polyester polyol using aliphatic diisocyanates, alicyclic diisocyanates, and polyisocyanates obtained therefrom.

When the one-component coating composition of the present embodiment is used as a water-based base coating, some carboxylic acid derived from a dibasic acid or the like in the polyester polyol is left, and a base such as amine or ammonia is used. By mixing, the polyester polyol can be made water soluble or water dispersible resin.

[Polyether polyol]
The polyether polyol can be obtained, for example, using any of the following methods (1) to (3).

(1) A method of obtaining polyether polyols by random or block addition of an alkylene oxide alone or a mixture with a polyhydroxy compound alone or a mixture using a catalyst.
Examples of the catalyst include hydroxides (lithium, sodium, potassium, etc.), strongly basic catalysts (alcoholate, alkylamines, etc.), complex metal cyanide complexes (metal porphyrin, zinc hexacyanocobaltate complex, etc.), etc. Be
Examples of the alkylene oxide include ethylene oxide, propylene oxide, butylene oxide, cyclohexene oxide, styrene oxide and the like.

(2) A method for obtaining polyether polyols by reacting an alkylene oxide with a polyamine compound.
Examples of the polyamine compound include ethylene diamines.
As said alkylene oxide, the thing similar to what was illustrated by (1) is mentioned.

(3) A method of polymerizing acrylamide or the like with the polyether polyols obtained in (1) or (2) as a medium to obtain so-called polymer polyols.

Examples of the polyvalent hydroxy compound include the following.
(I) diglycerin, ditrimethylolpropane, pentaerythritol, dipentaerythritol and the like.
(Ii) Sugar alcohol compounds such as erythritol, D-threitol, L-arabinitol, ribitol, xylitol, sorbitol, mannitol, galactitol, rhamnitol and the like.
(Iii) Monosaccharides such as arabinose, ribose, xylose, glucose, mannose, galactose, fructose, sorbose, rhamnose, fucose, ribodese and the like.
(Iv) Disaccharides such as trehalose, sucrose, maltose, cellobiose, gentiobiose, lactose, melibiose and the like.
(V) Trisaccharides such as raffinose, gentianose, and meletitose.
(Vi) Tetrasaccharides such as stachyose.

[Acrylic polyol]
Acrylic polyols, for example, polymerize a polymerizable monomer having one or more active hydrogens in one molecule, or, if necessary, a polymerizable monomer having one or more active hydrogens in one molecule. It can be obtained by copolymerizing the polymerizable monomer and the other copolymerizable monomer.
Examples of the polymerizable monomer having one or more active hydrogens in one molecule include the following. These may be used alone or in combination of two or more.

(I) Acrylic acid esters having active hydrogen such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxybutyl acrylate and the like.
(Ii) Methacrylic acid having active hydrogen such as 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl methacrylate, 3-hydroxypropyl methacrylate, 4-hydroxybutyl methacrylate and the like Esters.
(Iii) (Meth) acrylic acid esters having polyvalent active hydrogen such as (meth) acrylic acid monoester of triol such as glycerin and trimethylolpropane.
(Iv) Monoethers of polyether polyols (for example, polyethylene glycol, polypropylene glycol, polybutylene glycol etc.) and (meth) acrylic esters having the above-mentioned active hydrogen.
(V) An adduct of glycidyl (meth) acrylate and a monobasic acid (eg, acetic acid, propionic acid, p-tert-butylbenzoic acid, etc.).
(Vi) An adduct obtained by ring-opening polymerization of lactones (eg, ε-caprolactam, γ-valerolactone, etc.) with active hydrogen of the (meth) acrylic acid ester having the above-mentioned active hydrogen.

Examples of the other monomer copolymerizable with the polymerizable monomer include the following. These may be used alone or in combination of two or more.

(I) methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, methacrylic acid (Meth) acrylic esters such as isobutyl, n-hexyl methacrylate, cyclohexyl methacrylate, lauryl methacrylate, glycidyl methacrylate and the like.
(Ii) Unsaturated amides such as acrylic acid, methacrylic acid, maleic acid, itaconic acid and the like (unsaturated carboxylic acids such as acrylamide, N-methylol acrylamide, diacetone acrylamide and the like).
(Iii) Vinyl monomers having a hydrolyzable silyl group such as vinyltrimethoxysilane, vinylmethyldimethoxysilane, γ- (meth) acrylopropyltrimethoxysilane and the like.
(Iv) Other polymerizable monomers such as styrene, vinyl toluene, vinyl acetate, acrylonitrile and dibutyl fumarate.

As a specific production method of the acrylic polyol, for example, the above-mentioned monomer (monomer) component is solution-polymerized in the presence of a known radical polymerization initiator such as peroxide or azo compound, and, if necessary, Examples thereof include a method of obtaining an acrylic polyol by dilution with an organic solvent or the like.

When the one-component coating composition of the present embodiment is used as a water-based base coating, a known method such as solution polymerization of the above-mentioned monomer component and conversion to an aqueous layer or emulsion polymerization is used. Thus, a water-based acrylic polyol can be produced. In that case, it is possible to impart water solubility or water dispersibility to the acrylic polyol by neutralizing an acidic moiety such as a carboxylic acid-containing monomer such as acrylic acid or methacrylic acid or a sulfonic acid-containing monomer with an amine or ammonia. it can.

[Polyolefin polyol]
Examples of polyolefin polyols include polybutadiene having two or more hydroxyl groups, hydrogenated polybutadiene having two or more hydroxyl groups, polyisoprene having two or more hydroxyl groups, hydrogenated polyisoprene having two or more hydroxyl groups, and the like.
Further, in the polyolefin polyol, the number of hydroxyl groups is preferably 3 because higher coating strength can be obtained.

[Fluorine polyol]
As used herein, "fluorine polyol" means a polyol containing fluorine in the molecule. Specific examples of the fluorine polyol include fluoroolefins, cyclovinyl ethers and hydroxy compounds disclosed in, for example, JP-A-57-34107 (Reference 4) and JP-A-61-275311 (Reference 5). Copolymers, such as alkyl vinyl ether and monocarboxylic acid vinyl ester, etc. are mentioned.

[Hydroxyl value and acid value of polyol]
The lower limit value of the hydroxyl value of the polyol is preferably 10 mg KOH / g or more, more preferably 20 mg KOH / g or more, and still more preferably 30 mg KOH / g or more.
On the other hand, the upper limit value of the hydroxyl value of the polyol is not particularly limited, and may be, for example, 200 mg KOH / g or less.
That is, the hydroxyl value of the polyol is preferably 10 mg KOH / g or more and 200 mg KOH / g or less, more preferably 20 mg KOH / g or more and 200 mg KOH / g or less, and further preferably 30 mg KOH / g or more and 200 mg KOH / g or less preferable.
Moreover, it is preferable that the acid value of a polyol is 0 mgKOH / g or more and 30 mgKOH / g or less.
The hydroxyl value and the acid value can be measured in accordance with JIS K1557.

[NCO / OH]
0.2 or more and 5.0 or less are preferable, and 0.4 or more and 3.0 or less of the molar equivalent ratio (NCO / OH) of the isocyanate group of the above-mentioned block isocyanate composition to the hydroxyl group of the said polyol are more preferable, 0 More preferably, it is not less than 0.5 and not more than 2.0. When the molar equivalent ratio is equal to or more than the above lower limit value, it is possible to obtain a tougher coating. By the said molar equivalent ratio being below the said upper limit, the smoothness of the coating film obtained can be improved further.

<Other ingredients contained>
[Melamine based curing agent]
The one-component coating composition of the present embodiment may contain a melamine-based curing agent such as a complete alkyl type, methylol type alkyl, imino group type alkyl, etc., as necessary.

[Organic solvent]
The one-component coating composition of the present embodiment may contain an organic solvent.
Moreover, the said polyol and the above-mentioned blocked isocyanate composition may contain the organic solvent.
As an organic solvent, what is necessary is just to have a functional group which reacts with a hydroxyl group and an isocyanate group. Moreover, it is preferable to be compatible with the above-mentioned blocked isocyanate composition.
Specific examples of the organic solvent include ester compounds such as butyl acetate, ether compounds, ketone compounds, aromatic compounds, ethylene glycol dialkyl ether compounds, polyethylene glycol dicarboxylate compounds, hydrocarbon solvents, aroma And organic solvents generally used as paint solvents such as group solvents.

The one-pack type paint composition of the present embodiment is a catalyst for promoting curing, a pigment, a leveling agent, an antioxidant, an ultraviolet absorber, and the like within the range not to impair the effects of the present embodiment depending on the purpose and application. It may contain various additives used in the art such as light stabilizers, plasticizers, surfactants and the like.
Moreover, the said polyol and the above-mentioned block isocyanate composition may contain the said various additive.

As a catalyst for accelerating the curing, for example, metal salts such as dibutyltin dilaurate, tin 2-ethylhexanoate, zinc 2-ethylhexanoate, cobalt salt, etc .; triethylamine, pyridine, methylpyridine, benzyldimethylamine, N, N-dimethyldimethylamine And tertiary amines such as cyclohexylamine, N-methylpiperidine, pentamethyldiethylenetriamine, N, N'-endoethylenepiperazine, N, N'-dimethylpiperazine and the like.

The one-component coating composition of the present embodiment can be used, for example, as a coating such as roll coating, curtain flow coating, spray coating, bell coating, electrostatic coating and the like.
In addition, the one-component coating composition of the present embodiment is useful as, for example, a primer for a material such as metal (steel sheet, surface-treated steel sheet, etc.), plastic, wood, film, inorganic material, and upper middle coat.
In addition, the one-component coating composition of the present embodiment imparts, for example, a precoat metal including a rust-proof steel plate, a coated part of an automobile, etc. with a cosmetic property, weather resistance, acid resistance, rust resistance, chipping resistance, etc. It is also useful as a paint for
In addition, the one-component coating composition of the present embodiment is also useful as a urethane raw material such as, for example, an adhesive, a pressure-sensitive adhesive, an elastomer, a foam, and a surface treatment agent.

<Method of producing one-pack type paint composition>
The one-component coating composition of the present embodiment may be either solvent-based or water-based.
When the one-pack coating composition is solvent-based, it can be prepared by the following method. First, if necessary, additives such as other resins, catalysts, pigments, leveling agents, antioxidants, UV absorbers, light stabilizers, plasticizers, surfactants, etc. are added to the polyol or its solvent diluent. . Next, the above-described blocked isocyanate composition is added as a curing agent, and if necessary, a solvent is further added to adjust the viscosity. Then, the solvent-based one-component coating composition can be obtained by stirring with a hand or using a stirring device such as Magellar.

When the one-pack type paint composition is water-based, it can be prepared by the following method. First, according to need, other resins, catalysts, pigments, leveling agents, antioxidants, UV absorbers, light stabilizers, plasticizers, surfactants, as needed, to water dispersions or water soluble substances of polyols containing resins Add additives such as Then, the above-described blocked isocyanate composition is added as a curing agent, and water and a solvent are further added, if necessary, and then forced agitation is performed using a stirring device to obtain an aqueous-based one-component coating composition. Can.

«Coating film»
The coating film which concerns on one Embodiment of this invention hardens the above-mentioned one-component-type coating composition.
The coating film of this embodiment is obtained by coating and curing the above-described one-component coating composition using a known method such as roll coating, curtain flow coating, spray coating, bell coating, electrostatic coating and the like. Be
The coating film of the present embodiment has good weatherability and hardness.

Hereinafter, the present embodiment will be more specifically described with reference to specific examples and comparative examples, but the present embodiment is not limited at all by the following examples and comparative examples as long as the gist thereof is not exceeded. Absent. Physical properties of the polyisocyanate composition in Examples and Comparative Examples were measured as follows. In addition, "part" and "%" mean "mass part" and "mass%", unless otherwise specified.

«Evaluation items»
The physical properties and the respective properties of the blocked isocyanate composition produced in Examples and Comparative Examples, the coating composition containing the blocked isocyanate composition, and the coating film obtained by curing the coating composition according to the method described below I made an evaluation.

<NCO content>
The NCO content (% by mass) was determined by back titration with 1N hydrochloric acid after neutralizing the isocyanate group in the measurement sample with excess 2N amine.

<Calculated NCO content>
The NCO content of the isocyanate composition used at the time of synthesis of the blocked isocyanate composition was determined by the above-described back titration method, and the NCO content mass [A] was determined from the mass of the charged isocyanate composition.
Next, the calculated NCO content was determined using Formula [1] shown below.
Calculated NCO content (mass%) = 100 × [A] / total preparation mass [1]

<Viscosity>
The viscosity was measured at 25 ° C. using an E-type viscometer (manufactured by Tokimec). In measurement, a standard rotor (1 ° 34 ′ × R24) was used. The rotation speed was set as shown below.
100 rpm (in the case of less than 128 mPa · s)
50 rpm (in the case of 128 mPa · s or more and less than 256 mPa · s)
20 rpm (in the case of 256 mPa · s or more and less than 640 mPa · s)
10 rpm (in the case of 640 mPa · s or more and less than 1280 mPa · s)
5 rpm (in the case of 1280 mPa · s or more and less than 2560 mPa · s)

<Method for evaluating viscosity reduction degree of blocked isocyanate composition>
Two hours after the synthesis, the viscosity at 25 ° C. of the blocked isocyanate composition was measured using an E-type viscometer (manufactured by Tokimec) as described above.
As the evaluation method, the case where the viscosity is less than 800 mPa · s is ○, and the case where the viscosity is 800 mPa · s or more is x.

<Method for evaluating crystallization of blocked isocyanate composition>
40 g of the blocked isocyanate composition was charged in a 50 mL sample bottle, stored at 23 ° C., and crystallization was visually observed.
As an evaluation method, the case where it does not crystallize in 30 days or more is 、, the case where it crystallizes in 2 days or more and less than 30 days is 場合, the case where it crystallizes in 1 day or more and less than 2 days is Δ, the crystals in less than 1 day The case of conversion was regarded as x.

<Method for Evaluating Low-Temperature Curability of Blocked Isocyanate Composition>
Each block isocyanate composition after evaluation of crystallinity and acrylic polyol (trade name “SETALUX 1152” manufactured by Nuplex Resin, resin content concentration 61%, hydroxyl value 84.6 mg KOH / g), molar equivalent of isocyanate group / hydroxy group The paint composition was prepared so as to be formulated at a ratio of 1.0 and to have a solid content of 50% by mass with butyl acetate. Each prepared coating composition was coated on a PP plate to a dry film thickness of 40 μm. Then, the film was heated at 110 ° C. for 30 minutes to be cured to obtain a coating.
Subsequently, the gel fraction of the obtained coating film was calculated using the method shown below, and low temperature curability was evaluated.
Specifically, the gel fraction (% by mass) was obtained by immersing the obtained coated film in acetone at 23 ° C. for 24 hours, and then the ratio of the mass of the undissolved portion to the coated film mass before immersion was calculated.
In addition, as the evaluation method, the case where the gel fraction is 85% by mass or more is ◎, the case where 70% by mass or more and less than 85% by mass is ○, the case where 20% by mass or more and less than 70% by mass is Δ, less than 20% by mass The combination of was marked x.

<Method for evaluating storage stability of paint>
Each block isocyanate composition after evaluation of crystallinity and acrylic polyol (trade name “SETALUX 1152” manufactured by Nuplex Resin, resin content concentration 61%, hydroxyl value 84.6 mg KOH / g), molar equivalent of isocyanate group / hydroxy group The paint composition was prepared so as to be formulated at a ratio of 1.0 and to have a solid content of 50% by mass with butyl acetate. Each of the prepared coating compositions was stored at 40 ° C. for 30 days, and the low-temperature curing evaluation was carried out. The case where the percentage change in gel fraction before and after storage was less than 15% was ○, and the case of 15% or more was x.

Synthesis Example 1 Synthesis of NTI 4-Aminomethyl-1,8-octamethylenediamine (hereinafter sometimes referred to as “triamine”) in a four-necked flask equipped with a stirrer, thermometer, and gas inlet tube 1060 g was dissolved in 1500 g of methanol, and to this, 1800 mL of 35% concentrated hydrochloric acid was gradually added dropwise while cooling. It was then concentrated under reduced pressure to remove methanol and water, and dried at 60 ° C./5 mmHg for 24 hours to obtain triamine hydrochloride as a white solid. The obtained triamine hydrochloride (650 g) was suspended as a fine powder in 5000 g of o-dichlorobenzene, and the temperature of the reaction solution was raised while stirring. Then, when the reaction solution reached 100 ° C., phosgene was started to be blown at a rate of 200 g / hr and heating was continued further. Then, when the reaction solution reached 180 ° C., the temperature was maintained and phosgene was kept blowing for 12 hours. Subsequently, the dissolved phosgene and the solvent were distilled off under reduced pressure, and vacuum distillation was performed to obtain 420 g of a colorless and transparent NTI having a boiling point of 161 to 163 ° C./1.2 mmHg. The NCO content of NTI was 50.0% by weight.

Synthesis Example 2 Synthesis of LTI 122.2 g of ethanolamine, 100 mL of o-dichlorobenzene, and 420 mL of toluene are placed in a four-necked flask equipped with a stirrer, thermometer, and gas inlet tube, and ice-cold hydrogen chloride gas is added It was introduced and ethanolamine was converted to hydrochloride. Next, 182.5 g of lysine hydrochloride was added, the reaction solution was heated to a temperature of 80 ° C., ethanolamine hydrochloride was dissolved, and hydrogen chloride gas was introduced to form lysine dihydrochloride. Then, hydrogen chloride gas was passed at 20 to 30 mL / min, and the reaction solution was heated to a temperature of 116 ° C. and maintained at this temperature until water did not distill. Then, the resulting reaction mixture was recrystallized in a mixture of methanol and ethanol to obtain 165 g of lysine β-aminoethyl ester trihydrochloride. 100 g of this lysine β-aminoethyl ester trihydrochloride was suspended as a fine powder in 1200 mL of o-dichlorobenzene, and the temperature of the reaction solution was raised while stirring. Then, when the reaction liquid reached 120 ° C., phosgene was started to be blown at a rate of 0.4 mol / hour and maintained for 10 hours. Then, the temperature of the reaction solution was raised to 150 ° C. to almost dissolve lysine β-aminoethyl ester trihydrochloride in the reaction solution. After cooling, the solution was filtered, and the dissolved phosgene and the solvent were distilled off under reduced pressure. Then, vacuum distillation was performed to obtain 80.4 g of a colorless and transparent LTI having a boiling point of 155 to 157 ° C./0.022 mmHg. The NCO content of LTI was 47.1 wt%.

Example 1 Production of Blocked Isocyanate Composition 1 A four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen blow-in pipe was made to have a nitrogen atmosphere, and NTI (10.0 g), butyl acetate (9. 9 g). 0 g) was charged and the temperature was adjusted to 70.degree. Subsequently, 3,5-dimethylpyrazole (5.7 g, 50 mol%) and methyl ethyl ketoxime (5.2 g, 50 mol%) were added dropwise to a four-necked flask and maintained for 2 hours. Next, an NCO content of 0.0% by mass was confirmed, and a blocked isocyanate composition 1 was obtained.
The calculated NCO content of the resulting blocked isocyanate composition 1 was 16.8% by mass. Furthermore, the evaluation of degree of viscosity reduction was 結晶, the evaluation of crystallization was ◎, the evaluation of low temperature curability was △, and the storage stability evaluation of the paint was ○. The results are shown in Table 1.

[Examples 2 to 5 and 7 to 12 and Comparative Examples 1 and 2] Preparation of Blocked Isocyanate Composition 2 to 5 and 7 to 14 The used mass of the triisocyanate compound, the blocking agent and the diluent, and the addition ratio of the blocking agent Blocked isocyanate compositions 2 to 5 and 7 to 14 were produced in the same manner as in Example 1 except that the conditions were as shown in Table 1 or Table 2. The calculated NCO content, the degree of viscosity reduction, the crystallization evaluation, and the low-temperature curing results of each of the obtained blocked isocyanate compositions are shown in Table 1 or Table 2.
In Comparative Example 1, the crystallization was so remarkable that the coating composition could not be prepared, and the low temperature curability and the storage stability of the coating could not be evaluated.

Example 6 Production of Blocked Isocyanate Composition 6 A four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen blow-in pipe was made to have a nitrogen atmosphere, and NTI (10.0 g), butyl acetate (3. 6 g), diethyl malonate (9.5 g, 50 mol%) was charged and the temperature was brought to 70.degree. Next, a 30% by mass methanol solution (0.05 g) of sodium methylate was added to a four-necked flask and allowed to react at 70 ° C. for 3 hours. Subsequently, 3,5-dimethylpyrazole (5.7 g, 50 mol%) was added to a four-necked flask and held for 2 hours. Next, an NCO content of 0.0% by mass was confirmed, n-butanol (7.2 g) was added, and the mixture was kept at 70 ° C. for 2 hours to obtain a blocked isocyanate composition 6.
The calculated NCO content of the resulting blocked isocyanate composition 6 was 13.9% by mass. Further, the evaluation of degree of viscosity reduction was ○, the evaluation of crystallization was ◎, the evaluation of low temperature curability was ◎, and the storage stability evaluation of the paint was ○. The results are shown in Table 1.

Comparative Example 3 Production of Blocked Isocyanate Composition 15 A four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen blowing pipe is made into a nitrogen atmosphere, and HDI-based polyisocyanate (manufactured by Asahi Kasei Corp., TKA-100) ) (10.0 g) and butyl acetate (6.3 g) were charged and reacted at 120 ° C. for 3 hours. The temperature was then lowered to 70 ° C., 3,5-dimethylpyrazole (2.5 g, 50 mol%) and methyl ethyl ketoxime (2.2 g, 50 mol%) were added and held for 2 hours. Next, an NCO content of 0.0% by mass was confirmed, and a blocked isocyanate composition 15 was obtained.
The calculated NCO content of the obtained blocked isocyanate composition 11 was 10.3% by mass. Furthermore, the evaluation of degree of viscosity reduction was x, the evaluation of crystallization was ◎, the evaluation of low temperature curability was ◎, and the evaluation of storage stability of the paint was ○. The results are shown in Table 2.

Comparative Example 4 Production of Blocked Isocyanate Composition 16 The same method as Comparative Example 3 except that the use amounts of the HDI-based polyisocyanate, the blocking agent and the diluent, and the addition ratio of the blocking agent are as shown in Table 2. To produce a blocked isocyanate composition 16. The calculated NCO content, the degree of viscosity reduction, the crystallization evaluation, and the low temperature curability results of the obtained blocked isocyanate composition 16 are shown in Table 2.

The blocked isocyanate compositions obtained in Examples 1 to 12 had low viscosity, low crystallinity and low temperature curability, and were excellent in the storage stability of the paint.
On the other hand, in the blocked isocyanate composition obtained in Comparative Example 1, the crystallization was so remarkable that the paint composition could not be prepared, and the evaluation of low temperature curability and storage stability of the paint could not be carried out.
The blocked isocyanate composition obtained in Comparative Example 2 was inferior in low temperature curability.
The blocked isocyanate composition obtained in Comparative Example 3 had a high viscosity.
The blocked isocyanate composition obtained in Comparative Example 4 had a high viscosity and was inferior in the storage stability of the paint.
From the above, it was confirmed that the blocked isocyanate composition of the present embodiment has a low viscosity and is excellent in low-temperature curability and low crystallinity.

The blocked isocyanate composition of the present embodiment has a low viscosity, and has excellent low crystallinity and low temperature curability. Moreover, the one-component coating composition using the blocked isocyanate composition as a curing agent can be used as a coating for roll coating, curtain flow coating, spray coating, bell coating, electrostatic coating and the like. Moreover, the one-component coating composition using the block isocyanate composition as a curing agent is a primer such as a steel plate, a metal such as a surface-treated steel plate, and a primer or a top middle coat on a material such as plastic, wood, film or inorganic material. It can be used as a paint. In addition, the one-component coating composition using the blocked isocyanate composition as a curing agent imparts heat resistance, cosmetic properties (surface smoothness, sharpness), etc. to a precoated metal containing a rustproof steel plate, automobile coating, etc. It is also useful as a paint. The one-component coating composition using the blocked isocyanate composition as a curing agent is also useful as a urethane material for adhesives, adhesives, elastomers, foams, surface treatment agents and the like.

Claims (5)

1. A blocked isocyanate composition comprising a blocked isocyanate compound obtained from a triisocyanate compound represented by the following general formula (I) and at least two blocking agents.
   

   

   In the general formula (I), a plurality of Y ^{1 s} each independently represent a single bond or a divalent C 1 -C 20 divalent group which may contain at least one selected from the group consisting of an ester structure and an ether structure It is a hydrocarbon group. The plurality of Y ¹ may be identical to or different from each other. R ¹ is a hydrogen atom or a monovalent hydrocarbon group having 1 to 12 carbon atoms.
2. The blocked isocyanate composition according to claim 1, wherein the at least two blocking agents include at least one selected from the group consisting of an amine compound and an active methylene compound, and a pyrazole compound.
3. The blocked isocyanate composition according to claim 1 or 2, wherein the proportion of isocyanate groups blocked by the pyrazole compound among the isocyanate groups blocked by the blocking agent is 20 mol% to 80 mol%.
4. A one-component coating composition comprising the blocked isocyanate composition according to any one of claims 1 to 3 and a polyol.
5. The coating film which hardened | cured the one-component coating composition of Claim 4.