JPWO2018235896A1 - Block isocyanate composition, one-component coating composition and coating film - Google Patents

Abstract

The blocked isocyanate composition of the present invention comprises the following general formula (I) (wherein, a plurality of Y1s each independently include a single bond or at least one selected from the group consisting of an ester structure and an ether structure) May be a divalent hydrocarbon group having 1 to 20 carbon atoms, and a plurality of Y 1 may be the same or different, and R 1 is a hydrogen atom or a monovalent C 1 to C 12 (Which is a hydrocarbon group) and at least two types of blocking agents. Embedded image

Description

The present invention relates to a blocked isocyanate composition, a one-component coating composition, and a coating film.
This application claims priority based on Japanese Patent Application No. 2017-123599 for which it applied to Japan on June 23, 2017, and uses the content here.

  Conventionally, a urethane coating film formed from a polyurethane paint has very excellent flexibility, chemical resistance, and stain resistance. In particular, a coating film using a non-yellowing polyisocyanate composition obtained from an aliphatic diisocyanate typified by hexamethylene diisocyanate (hereinafter sometimes referred to as “HDI”) as a curing agent is further improved in weather resistance. And its demand is increasing.

  2. Description of the Related Art In recent years, technological development for reducing the viscosity of polyisocyanate compositions used as curing agents has been actively performed due to the enhancement of global environmental protection. This is because the amount of the organic solvent used in the coating composition can be reduced by reducing 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 amount of the organic solvent can be reduced by using these triisocyanate compounds in a coating composition.

  The polyisocyanate composition forms a crosslinked coating film at room temperature with a polyol. The polyisocyanate composition is widely used for baking coating as a heat-crosslinking type curing agent together with a melamine curing agent. In recent years, it has been pointed out that formalin is generated when a melamine curing agent is used. Therefore, from the viewpoints of the global environment, safety, hygiene, and the like, a polyisocyanate (block polyisocyanate) composition blocked by a blocking agent that dissociates isocyanate groups in the polyisocyanate composition by heating has attracted attention.

  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 Documents 7 and 8 disclose triisocyanate blocked with a pyrazole compound as a blocking agent (hereinafter sometimes referred to as “blocked triisocyanate”). Further, for example, Patent Document 9 discloses a block polyisocyanate composition containing at least one selected from the group consisting of aliphatic isocyanates and alicyclic isocyanates blocked using pyrazole compounds and oxime compounds as blocking agents. Things are disclosed.

JP 05-222007 A Japanese Patent No. 3055197 Japanese Examined Patent Publication No. 63-015264 JP-A-53-135931 Japanese Patent Laid-Open No. 60-045461 European Patent Application Publication No. 159117 Japanese Patent No. 4671668 JP 2005-154778 A JP 2011-236388 A

In block polyisocyanate compositions, there is a demand for both low viscosity and ability to form a crosslinked coating film at low temperatures.
However, the block polyisocyanate compositions described in Patent Documents 6 and 9 are cured at a relatively low temperature, but are insufficient from the viewpoint of lowering the viscosity.
Moreover, although the blocked triisocyanates described in Patent Documents 7 and 8 are cured at a relatively low temperature, the blocked triisocyanates crystallize, and thus cannot be used in liquid paints.

  The present invention has been made in view of the above circumstances, and provides a blocked isocyanate composition having a low viscosity and excellent in low crystallinity, low-temperature curability and coating storage stability. Moreover, the one-pack-type coating composition and coating film using the said block isocyanate composition are provided.

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 types of blocking agents.

In general formula (I), a plurality of Y ¹ are each independently a single bond or a divalent divalent having 1 to 20 carbon atoms that may contain at least one selected from the group consisting of an ester structure and an ether structure. It is a hydrocarbon group. A plurality of Y ¹ may be the same or different. 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 types of blocking agents include at least one selected from the group consisting of amine compounds and active methylene compounds and a pyrazole compound.
[3] The block according to [1] or [2], wherein a ratio of an isocyanate group blocked with the pyrazole compound out of the isocyanate group blocked with the blocking agent is 20 mol% to 80 mol%. Isocyanate composition.
[4] A one-component coating composition comprising the blocked isocyanate composition according to any one of [1] to [3] and a polyol.
[5] A coating film obtained by curing the one-component coating composition according to [4].

  According to the above aspect, it is possible to provide a blocked isocyanate composition having a low viscosity and having excellent low 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 block isocyanate composition.

Hereinafter, a mode for carrying out the present invention (hereinafter simply referred to as “the present embodiment”) will be described in detail. The following embodiments are examples for explaining the present invention, and are not intended to limit the present invention to the following contents. The present invention can be implemented with appropriate modifications within the scope of the gist thereof.
In the present specification, “polyisocyanate” means a polymer in which a plurality of monomers having one or more isocyanate groups (—NCO) are bonded.
In this specification, “polyol” means a compound having two or more hydroxy groups (—OH).
In this specification, unless otherwise specified, “(meth) acryl” includes methacryl and acryl. “(Meth) acrylate” includes methacrylate and acrylate.

≪Block isocyanate composition≫
The blocked isocyanate composition according to one embodiment of the present invention includes a triisocyanate compound represented by the following general formula (I) (hereinafter sometimes referred to as “triisocyanate compound (I)”) and at least two types of blocks. And a blocked isocyanate compound obtained from the agent.

In general formula (I), a plurality of Y ¹ are each independently a single bond or a divalent divalent having 1 to 20 carbon atoms that may contain at least one selected from the group consisting of an ester structure and an ether structure. It is a hydrocarbon group. A plurality of Y ¹ may be the same or different. 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 contains a blocked isocyanate compound obtained from the triisocyanate compound (I) and at least two types of blocking agents, and thus has low viscosity, low crystallinity, and low temperature curing. And excellent storage stability of the paint.

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

[Triisocyanate Compound (I)]
(Y ¹ )
In the general formula (I), a plurality of Y ¹ are each independently a single bond, or a divalent group having 1 to 20 carbon atoms that may contain at least one selected from the group consisting of an ester structure and an ether structure. It is a hydrocarbon group. A plurality of Y ¹ may be the same or different.

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.
Examples of the linear or branched aliphatic group include alkanediyl groups (alkylene groups) and alkylidene groups.
Examples of the cyclic aliphatic group include a cycloalkylene group.
Examples of the aromatic group include an arylene group such as a phenylene group.
Among these, as said hydrocarbon group, a C1-C6 alkylene group is preferable.

Table Examples of the divalent hydrocarbon groups of said ester structure and at least one of which may contain 1 to 20 carbon atoms selected from the group consisting of ether structure in Y ^1, for example, by the following general formula (II) Group to be used.
_{^{* 1 - (CH 2) n1}} -X- (CH 2) n2 - * 2 (II)

In the general formula (II), * ¹ represents a bond with C in the general formula (I), and * ² represents a bond with NCO in the general formula (I). N1 and n2 are each independently an integer of 0 to 20 that satisfies 1 ≦ n1 + n2 ≦ 20. That is, both n1 and n2 do not become 0, and n2 on the side bonded to the NCO is preferably 1 or more.
Among these, n1 and n2 are each independently preferably an integer of 0 to 4, and 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, a combination of n1 = 2 and n2 = 2 is preferable.

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

Further, when at least one of a plurality of Y ¹ has at least one of the group consisting of an aliphatic group and an aromatic group, the blocked isocyanate composition of the present embodiment can have a lower viscosity, The weather resistance of the coating film obtained by using the blocked isocyanate composition of the embodiment as a curing agent for the coating composition can be made better.

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

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 of R ^1, is not particularly limited, an alkyl group, an alkenyl group, an alkynyl group. Among these, as R ¹ , a hydrogen atom is preferable.

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, specific examples of preferred triisocyanate compound (I) include 4-isocyanatomethyl-1,8-octamethylene diisocyanate (hereinafter referred to as “NTI”, molecular weight 251) disclosed in Japanese Patent Publication No. 63-15264 (Patent Document 3), Japanese Patent Laid-Open No. 57-198760. 1,3,6-hexamethylene triisocyanate (hereinafter referred to as “HTI”, molecular weight 209) disclosed in Japanese Patent Publication (Reference Document 1), and Japanese Patent Publication No. 4-1033 (Reference Document 2). Bis (2-isocyanatoethyl) 2-isocyanatoglutarate (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).

Among these, from the viewpoint of further improving 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, the triisocyanate compound (I) Is preferably NTI, GTI or LTI, more preferably NTI or LTI, and even more preferably LTI.

In the present embodiment, when at least one of a plurality of Y ¹ has an ester structure, specific examples of preferable triisocyanate compound (I) include, for example, Japanese Patent Publication No. 4-1033 (reference document 2). GTI (molecular weight 311) disclosed in (2)), LTI (molecular weight 267) disclosed in JP-A-53-135931 (reference document 3), and the like.

In the present embodiment, when at least one of a plurality of Y ¹ is composed of only a hydrocarbon group, a preferable example of the triisocyanate compound (I) is, for example, Japanese Patent Publication No. 63-15264 (patent Examples thereof include NTI (molecular weight 251) disclosed in Reference 3), HTI (molecular weight 209) disclosed in JP-A-57-198760 (Reference 1), and the like.

  The triisocyanate compound can be obtained, for example, by subjecting amines such as amino acid derivatives, ether amines, and alkyl triamines to isocyanate.

  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, a triamine having an ester group can be obtained by esterifying the carboxyl group with an alkanolamine such as ethanolamine. The resulting triamine having an ester group can be converted to a triisocyanate compound having an ester structure by phosgenation of the amine.

  Examples of the ether amine include trade name “D403” of Mitsui Chemicals Fine, which is polyoxyalkylene triamine. These ether amines are triamines, and can be converted to triisocyanate compounds containing an ether structure by phosgenation of amines.

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

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, further preferably 180 or more, and particularly preferably 200 or more.
On the other hand, the upper limit 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, further 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 not less than the above lower limit value, the crystallinity can be further suppressed, and when it is not more than the above upper limit value, the viscosity can be further reduced.

[Blocking 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 with two or more types of blocking 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) Phenol 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. Specific examples of the blocking agent include those shown below.

(1) Pyrazole compounds: pyrazole, 3-methylpyrazole, 3,5-dimethylpyrazole and the like.
(2) Amine-based 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 compounds: formaldoxime, acetaldoxime, 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-ethoxy ethanol, 2-butoxyethanol, etc. .
(6) Alkylphenol compounds: mono- and dialkylphenols having an alkyl group having 4 or more carbon atoms as a substituent. Specific examples of alkylphenol compounds include n-propylphenol, iso-propylphenol, n-butylphenol, sec-butylphenol, t-butylphenol, n-hexylphenol, 2-ethylhexylphenol, n-octylphenol, and n-nonylphenol. Monoalkylphenols such as 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) Phenol 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: acetanilide, 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, ethyleneurea 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 includes at least one 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, it is more preferable that the at least two blocking agents contain an amine compound or an active methylene compound together with a pyrazole compound.

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

<Method for producing blocked isocyanate compound>
The blocking reaction between the triisocyanate compound and the blocking agent can be performed regardless of the presence or absence of a solvent, and a blocked isocyanate compound is obtained.

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, organometallic salts such as tin, zinc and lead, tertiary amine compounds, alcoholates of alkali metals such as sodium, and the like may be used as catalysts.

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

  In the blocked isocyanate composition of the present embodiment, the proportion of the isocyanate group 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. It is preferable that it is 70 mol% or less. Further, from the viewpoint of low temperature curability, 20 mol% or more is preferable, and 30 mol% or more is more preferable.

≪Block isocyanate composition of polyisocyanate≫
The blocked isocyanate composition of polyisocyanate according to one embodiment of the present invention includes a structure represented by the following general formula (III), an isocyanurate structure, a burette structure, a uretdione structure, an iminooxadiazinedione structure, a urethane structure, and an allophanate. The block isocyanate compound obtained from the polyisocyanate compound containing at least 1 sort (s) chosen from the group which consists of a structure, and a blocking agent is included.

In General Formula (III), Y ¹ and R ¹ are as described in General Formula (I).
The block isocyanate composition of the polyisocyanate of this embodiment is further excellent in low temperature curability.

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

<Hydrophilic blocked isocyanate compound>
By reacting the isocyanate group of the blocked isocyanate compound in the above-mentioned blocked isocyanate composition with the hydrophilic group-containing compound, a hydrophilic blocked isocyanate compound to which a hydrophilic group has been added can be obtained.
Although it does not specifically limit as a hydrophilic group containing compound which can react with an isocyanate group, For example, the compound containing hydrophilic groups, such as nonionic property, cationic property, and 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 hydrogens that react with isocyanate groups.
Especially, since the water dispersibility of a hydrophilic polyisocyanate composition can be improved with little usage-amount, as a compound containing a nonionic hydrophilic group, the monoalcohol which has ethylene oxide is preferable.

The content of ethylene oxide in the compound containing a nonionic hydrophilic group is preferably 4 or more and 30 or less, and more preferably 4 or more and 20 or less.
When the ethylene oxide content is not less than the above lower limit value, it tends to ensure water-based treatment. Moreover, when the ethylene oxide content is not more than the above upper limit value, precipitates of the hydrophilic blocked isocyanate composition tend not to occur 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 that reacts with the isocyanate group is used. Examples thereof include a method to be used and a method in which a functional group such as a glycidyl group is previously added to an isocyanate group, and then this functional group is reacted with a specific compound such as sulfide or phosphine.
Among them, when a cationic hydrophilic group is introduced into the above-mentioned blocked isocyanate compound to obtain a hydrophilic blocked isocyanate compound, since the reaction is easy, the cationic hydrophilic group has hydrogen that reacts with the isocyanate group. A method using a compound having both a functional group and a functional group is preferred.

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 that reacts with an isocyanate group is not particularly limited, and examples thereof include dimethylethanolamine, diethylethanolamine, diethanolamine, methyldiethanolamine, and N, N-dimethyl. Aminohexanol, N, N-dimethylaminoethoxyethanol, N, N-dimethylaminoethoxyethoxyethanol, N, N, N′-trimethylaminoethylethanolamine, N-methyl-N- (dimethylaminopropyl) aminoethanol, etc. Can be mentioned.

  Further, when the hydrophilic blocked 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 volatilize by heating, and as a result, the water resistance tends to be further improved.

  Moreover, introduction | transduction of the cationic hydrophilic group to the above-mentioned block isocyanate compound can be performed in presence of a solvent. The solvent preferably does not contain a functional group capable of reacting with an isocyanate group. Specific examples of the solvent include, but are not limited to, 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.

  The anionic group is not particularly limited, and examples thereof include a carboxyl group, a sulfonic acid group, a phosphoric acid group, a halogen group, and a sulfuric acid group.

The compound having one carboxyl group as the anionic group is not particularly limited, and examples thereof include formic acid, acetic acid, propionic acid, butyric acid, and lactic acid.
Moreover, it does not specifically limit as a compound which has a sulfonic acid group as an anion group, For example, an ethanesulfonic acid etc. are mentioned.
Moreover, it does not specifically limit as a compound which has a phosphoric acid group as an anion group, For example, phosphoric acid, acidic phosphoric acid ester, etc. are mentioned.
Moreover, it does not specifically limit as a compound which has a halogen group as an anion group, For example, hydrochloric acid etc. are mentioned.
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.
Especially, as a compound which has an anion group, the compound which has one carboxyl group is preferable, and an 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 obtained, for example, by reacting an active hydrogen that reacts with an isocyanate group and an active hydrogen of a compound having an anionic hydrophilic group with the isocyanate group of the above-mentioned blocked isocyanate compound. Can be obtained.

The compound having an active hydrogen and a carboxylic acid group is not particularly limited. For example, monohydroxy such as 1-hydroxyacetic acid, 3-hydroxypropanoic acid, 12-hydroxy-9-octadecanoic acid, hydroxypivalic acid, and lactic acid. Carboxylic acid; Examples thereof include polyhydroxycarboxylic acids such as dimethylolacetic acid, 2,2-dimethylolbutyric acid, 2,2-dimethylolpentanoic acid, dihydroxysuccinic acid, dimethylolpropionic acid and the like.
Of these, hydroxypivalic acid or dimethylolpropionic acid is preferred as the compound having active hydrogen and a carboxylic acid group.

  Although it does not specifically limit as a compound which has active hydrogen and a sulfonic acid group, For example, isethionic acid etc. are mentioned.

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.
Although it does not specifically limit as a compound which has a cationic group, For example, the amine compound etc. which are basic substances are mentioned.

Although it does not specifically limit as said amine compound, For example, ammonia, a water-soluble amino compound, etc. are mentioned.
The water-soluble amino compound is not particularly limited. For example, monoethanolamine, ethylamine, dimethylamine, diethylamine, triethylamine, propylamine, dipropylamine, isopropylamine, diisopropylamine, triethanolamine, butylamine, dibutylamine, 2 -Primary amines or secondary amines such as ethylhexylamine, ethylenediamine, propylenediamine, methylethanolamine, dimethylethanolamine, diethylethanolamine, morpholine; tertiary amines such as triethylamine, dimethylethanolamine and the like.

≪One-component paint composition≫
The one-component coating composition according to an embodiment of the present invention includes the above-described blocked isocyanate composition and a polyol.
The above-mentioned blocked isocyanate composition can be suitably used as a curing agent for the one-component coating composition of the present embodiment.
Therefore, the one-pack type coating composition of this embodiment can make the weather resistance of the coating film obtained favorable by including the above-mentioned block isocyanate composition.

<Polyol>
The one-component coating composition of this embodiment contains the above-mentioned blocked isocyanate composition and a polyol as a resin component.
Examples of the resin component other than the polyol include polyamine and polythiol.

  Examples of the polyol include polyester polyol, polyether polyol, acrylic polyol, polyolefin polyol, and fluorine polyol. Among these, acrylic polyols are preferable from the viewpoints of weather resistance, chemical resistance, and hardness. Alternatively, the polyol is preferably a polyester polyol from the viewpoints of mechanical strength and oil resistance.

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

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

  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. , 2-methylolpropanediol, ethoxylated trimethylolpropane and the like.

As a specific method for producing the polyester polyol, for example, the above-mentioned components are mixed and heated at about 160 to 220 ° C. to perform the condensation reaction.
Alternatively, for example, polycaprolactones obtained by ring-opening polymerization of lactones such as ε-caprolactone using a polyhydric alcohol can also be used as the polyester polyol.
These polyester polyols can be modified using aromatic diisocyanates, aliphatic diisocyanates, alicyclic diisocyanates, polyisocyanates obtained therefrom, and the like. Among these, from the viewpoint of weather resistance and yellowing resistance, the polyester polyol is preferably modified using an aliphatic diisocyanate, an alicyclic diisocyanate, and a polyisocyanate obtained therefrom.

  When the one-component coating composition of this embodiment is used as a water-based base coating, a part of the carboxylic acid derived from dibasic acid in the polyester polyol is allowed to remain, and a base such as amine or ammonia is used. By summing, the polyester polyol can be made into a water-soluble or water-dispersible resin.

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

(1) A method of obtaining a polyether polyol by randomly or block-adding an alkylene oxide alone or a mixture to a polyvalent hydroxy compound alone or a mixture using a catalyst.
Examples of the catalyst include hydroxides (lithium, sodium, potassium, etc.), strong basic catalysts (alcolate, alkylamine, etc.), complex metal cyanide complexes (metal porphyrin, hexacyanocobaltate zinc complex, etc.) and the like. It is done.
Examples of the alkylene oxide include ethylene oxide, propylene oxide, butylene oxide, cyclohexene oxide, and styrene oxide.

(2) A method of obtaining a polyether polyol by reacting an alkylene oxide with a polyamine compound.
As said polyamine compound, ethylenediamine etc. are mentioned, for example.
As said alkylene oxide, the thing similar to what was illustrated by (1) is mentioned.

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

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, and rhamnitol.
(Iii) Monosaccharides such as arabinose, ribose, xylose, glucose, mannose, galactose, fructose, sorbose, rhamnose, fucose and ribodesource.
(Iv) Disaccharides such as trehalose, sucrose, maltose, cellobiose, gentiobiose, lactose, melibiose.
(V) Trisaccharides such as raffinose, gentianose, and meletitose.
(Vi) Tetrasaccharides such as stachyose.

[Acrylic polyol]
Acrylic polyol, for example, polymerizes a polymerizable monomer having one or more active hydrogens in one molecule, or a polymerizable monomer having one or more active hydrogens in one molecule, if necessary, It can be obtained by copolymerizing a polymerizable monomer and another monomer copolymerizable.
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, and 2-hydroxybutyl acrylate.
(Ii) Methacrylic acid having active hydrogen such as 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl methacrylate, 3-hydroxypropyl methacrylate, and 4-hydroxybutyl methacrylate Esters.
(Iii) (meth) acrylic acid esters having polyvalent active hydrogen such as (meth) acrylic acid monoesters of triols such as glycerin and trimethylolpropane.
(Iv) Monoethers of polyether polyols (for example, polyethylene glycol, polypropylene glycol, polybutylene glycol, etc.) and (meth) acrylic acid esters having the above active hydrogen.
(V) Adducts of glycidyl (meth) acrylate and monobasic acids (for example, acetic acid, propionic acid, p-tert-butylbenzoic acid, etc.).
(Vi) An adduct obtained by ring-opening polymerization of a lactone (for example, ε-caprolactam, γ-valerolactone, etc.) to the active hydrogen of the (meth) acrylic acid ester having the active hydrogen.

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

  As a specific method for producing an acrylic polyol, for example, the above monomer component is solution-polymerized in the presence of a radical polymerization initiator such as a known peroxide or azo compound, and if necessary, The method of obtaining an acrylic polyol by diluting with an organic solvent etc. is mentioned.

  When the one-component coating composition of this embodiment is used as a water-based base coating, a known method such as a method in which the monomer (monomer) component is subjected to solution polymerization and converted into an aqueous layer or emulsion polymerization is used. Thus, an aqueous-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 the polyolefin polyol include polybutadiene having two or more hydroxyl groups, hydrogenated polybutadiene having two or more hydroxyl groups, polyisoprene having two or more hydroxyl groups, and hydrogenated polyisoprene having two or more hydroxyl groups.
Further, in the polyolefin polyol, the number of hydroxyl groups is preferably 3 because higher coating film strength can be obtained.

[Fluorine polyol]
In this specification, “fluorine polyol” means a polyol containing fluorine in the molecule. Specific examples of the fluoropolyol include fluoroolefins, cyclovinyl ethers, hydroxys disclosed in JP-A-57-34107 (reference 4), JP-A-61-275111 (reference 5), and the like. Examples thereof include copolymers such as alkyl vinyl ethers and monocarboxylic acid vinyl esters.

[Hydroxyl value and acid value of polyol]
The lower limit of the hydroxyl value of the polyol is preferably 10 mgKOH / g or more, more preferably 20 mgKOH / g or more, and further preferably 30 mgKOH / 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 mgKOH / g or less.
That is, the hydroxyl value of the polyol is preferably 10 mgKOH / g or more and 200 mgKOH / g or less, more preferably 20 mgKOH / g or more and 200 mgKOH / g or less, and further preferably 30 mgKOH / g or more and 200 mgKOH / 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 acid value can be measured according to JIS K1557.

[NCO / OH]
The molar equivalent ratio (NCO / OH) of the isocyanate group of the above-mentioned blocked isocyanate composition to the hydroxyl group of the polyol is preferably 0.2 or more and 5.0 or less, more preferably 0.4 or more and 3.0 or less. More preferably, it is 5 or more and 2.0 or less. When the molar equivalent ratio is not less than the above lower limit value, a tougher coating film can be obtained. The smoothness of the coating film obtained can be further improved because the said molar equivalent ratio is below the said upper limit.

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

[Organic solvent]
The one-component coating composition of this embodiment may contain an organic solvent.
Moreover, the said polyol and the above-mentioned block isocyanate composition may contain the organic solvent.
Any organic solvent may be used as long as it does not have a functional group that reacts with a hydroxyl group and an isocyanate group. Moreover, it is preferable that it is 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, aromatic solvents. Examples thereof include organic solvents generally used as paint solvents such as group solvents.

The one-component coating composition of the present embodiment is a catalyst for promoting curing, a pigment, a leveling agent, an antioxidant, an ultraviolet absorber, within a range that does not impair the effect of the present embodiment, depending on the purpose and application. You may contain the various additives currently used in the said technical field, such as a light stabilizer, a plasticizer, and surfactant.
Moreover, the said polyol and the above-mentioned block isocyanate composition may contain the said various additives.

  Examples of the catalyst for accelerating the curing include metal salts such as dibutyltin dilaurate, tin 2-ethylhexanoate, zinc 2-ethylhexanoate, and cobalt salt; triethylamine, pyridine, methylpyridine, benzyldimethylamine, N, N-dimethyl. And tertiary amines such as cyclohexylamine, N-methylpiperidine, pentamethyldiethylenetriamine, N, N′-endoethylenepiperazine, and N, N′-dimethylpiperazine.

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

<Method for producing one-component coating composition>
The one-component coating composition of this embodiment may be either solvent-based or water-based.
When the one-component coating composition is solvent-based, it can be prepared by the following method. First, additives such as other resins, catalysts, pigments, leveling agents, antioxidants, ultraviolet absorbers, light stabilizers, plasticizers, surfactants, etc. are added to polyols or solvent dilutions as necessary. . Next, the above-mentioned blocked isocyanate composition is added as a curing agent, and a solvent is further added as necessary to adjust the viscosity. Next, a solvent-based one-component coating composition can be obtained by stirring using a stirring device such as hand stirring or a mazeller.

  When the one-component coating composition is water-based, it can be prepared by the following method. First, an aqueous dispersion of a resin containing a polyol, or a water-soluble substance, and if necessary, other resins, catalysts, pigments, leveling agents, antioxidants, ultraviolet absorbers, light stabilizers, plasticizers, surfactants Add additives such as. Next, the above-mentioned blocked isocyanate composition is added as a curing agent, and water or a solvent is further added as necessary, followed by forced stirring with a stirrer to obtain an aqueous base one-component coating composition. Can do.

≪Coating film≫
The coating film which concerns on one Embodiment of this invention hardens the above-mentioned one-component 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, or the like. It is done.
The coating film of this embodiment has good weather resistance and hardness.

  Hereinafter, the present embodiment will be described more specifically with specific examples and comparative examples. However, the present embodiment is not limited to the following examples and comparative examples unless they exceed the gist of the present embodiment. Absent. The physical properties of the polyisocyanate compositions in Examples and Comparative Examples were measured as follows. Unless otherwise specified, “parts” and “%” mean “parts by mass” and “mass%”.

≪Evaluation item≫
According to the methods shown below, the block isocyanate compositions produced in the examples and comparative examples, the coating compositions containing the blocked isocyanate compositions, and the coating films obtained by curing the coating compositions, each physical property and each Evaluation was performed.

<NCO content>
The NCO content (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 during the synthesis of the blocked isocyanate composition was determined by the above-described method by back titration, and the NCO-containing mass [A] was determined from the mass of the charged isocyanate composition.
The calculated NCO content was then determined using equation [1] below.
Calculated NCO content (mass%) = 100 × [A] / total charge mass [1]

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

<Method for evaluating the degree of viscosity reduction of the 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 an evaluation method, a case where the viscosity is less than 800 mPa · s is indicated by “◯”, and a case where the viscosity is 800 mPa · s or more is indicated by “X”.

<Method for evaluating crystallization of blocked isocyanate composition>
40 g of the blocked isocyanate composition was placed in a 50 mL sample bottle, stored at 23 ° C., and crystallization was visually observed.
The evaluation method is as follows: when crystallized after 30 days or more, ◎ when crystallized after 2 days or more but less than 30 days, △ when crystallized after 1 day or more but less than 2 days, crystallized after less than 1 day The case where it turned into was made x.

<Method for evaluating low-temperature curability of blocked isocyanate composition>
Each block isocyanate composition after crystallinity evaluation and acrylic polyol (trade name “SETALUX1152” of Nuplex Resin, resin concentration 61%, hydroxyl value 84.6 mgKOH / g), isocyanate group / hydroxyl molar equivalent The coating composition was prepared so that it might mix | blend by ratio 1.0 and solid content may be 50 mass% with butyl acetate. Each prepared coating composition was applied on a PP plate so as to have a dry film thickness of 40 μm. Subsequently, it heated at 110 degreeC for 30 minutes, and was hardened, and the coating film was obtained.
Subsequently, the gel fraction of the obtained coating film was computed using the method shown below, and low temperature curability was evaluated.
Specifically, the gel fraction (mass%) was obtained by immersing the obtained coating film in acetone at 23 ° C. for 24 hours and then calculating the ratio of the mass of the undissolved part to the coating film mass before immersion.
Further, as evaluation methods, the case where the gel fraction is 85% by mass or more is ◎, the case where it is 70% by mass or more and less than 85% by mass, the case where it is 20% by mass or more and less than 70% by mass, Δ, or less than 20% by mass The result was marked with x.

<Method for evaluating the storage stability of paints>
Each block isocyanate composition after crystallinity evaluation and acrylic polyol (trade name “SETALUX1152” of Nuplex Resin, resin concentration 61%, hydroxyl value 84.6 mgKOH / g), isocyanate group / hydroxyl molar equivalent The coating composition was prepared so that it might mix | blend by ratio 1.0 and solid content may be 50 mass% with butyl acetate. Each of the prepared coating compositions was subjected to the low-temperature curability evaluation after storage at 40 ° C. for 30 days, and the case where the change rate of the gel fraction before and after storage was less than 15% was evaluated as ◯, and the case where it was 15% or more was evaluated as ×.

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, a thermometer, and a gas introduction tube 1060 g was dissolved in 1500 g of methanol, and 1800 mL of 35% concentrated hydrochloric acid was gradually added dropwise thereto while cooling. Subsequently, methanol and water were removed under reduced pressure, and the mixture was concentrated and dried at 60 ° C./5 mmHg for 24 hours to obtain a white solid triamine hydrochloride. 650 g of the resulting triamine hydrochloride was suspended as a fine powder in 5000 g of o-dichlorobenzene, and the temperature of the reaction solution was increased while stirring. Next, when the reaction solution reached 100 ° C., phosgene was started to be blown at a rate of 200 g / Hr, and the temperature was further raised. Next, when the reaction solution reached 180 ° C., the temperature was maintained as it was, and phosgene was continuously blown in for 12 hours. Next, after distilling off the dissolved phosgene and the solvent under reduced pressure, 420 g of colorless and transparent NTI having a boiling point of 161 to 163 ° C./1.2 mmHg was obtained by vacuum distillation. The NCO NCO content 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 were placed in a four-necked flask equipped with a stirrer, a thermometer, and a gas introduction tube, and ice-cooled hydrogen chloride gas was added. And ethanolamine was converted to the hydrochloride salt. Next, 182.5 g of lysine hydrochloride was added, the reaction solution was heated to 80 ° C., ethanolamine hydrochloride was dissolved, and hydrogen chloride gas was introduced to form lysine dihydrochloride. Next, hydrogen chloride gas was passed at 20 to 30 mL / min, the reaction solution was heated to a temperature of 116 ° C., and this temperature was maintained until no water distilled off. Next, the resulting reaction mixture was recrystallized in a mixed solution 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 fine powder in 1200 mL of o-dichlorobenzene, and the temperature of the reaction solution was raised while stirring. Next, when the reaction solution reached 120 ° C., phosgene was started to be blown at a rate of 0.4 mol / hour and held for 10 hours. Next, the temperature of the reaction solution was raised to 150 ° C., and most of lysine β-aminoethyl ester trihydrochloride in the reaction solution was dissolved. Subsequently, after cooling, it filtered and dissolved phosgene and the solvent were distilled off under reduced pressure. Next, 80.4 g of colorless and transparent LTI having a boiling point of 155 to 157 ° C./0.022 mmHg was obtained by vacuum distillation. The NCO content of LTI was 47.1% by weight.

[Example 1] Production of blocked isocyanate composition 1 A four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen blowing tube was placed in a nitrogen atmosphere, and NTI (10.0 g) and butyl acetate (9. 0 g) was added, and the temperature was set to 70 ° C. Subsequently, 3,5-dimethylpyrazole (5.7 g, 50 mol%) and methyl ethyl ketoxime (5.2 g, 50 mol%) were added dropwise to the four-necked flask and held for 2 hours. Then, NCO content rate 0.0 mass% was confirmed, and the blocked isocyanate composition 1 was obtained.
The calculated NCO content of the obtained blocked isocyanate composition 1 was 16.8% by mass. Furthermore, the evaluation of the 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 ◯. These results are shown in Table 1.

[Examples 2 to 5, 7 to 12 and Comparative Examples 1 and 2] Production of Blocked Isocyanate Compositions 2 to 5, and 7 to 14 The triisocyanate compound, the blocking agent, the used mass of the diluent, and the addition ratio of the blocking agent. Block 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. Table 1 or Table 2 shows the calculated NCO content, degree of viscosity reduction, crystallization evaluation, and low-temperature curability results for each of the obtained blocked isocyanate compositions.
In Comparative Example 1, the coating composition was remarkably crystallized, 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 blowing tube was placed in a nitrogen atmosphere, and NTI (10.0 g) and butyl acetate (3. 6 g) and diethyl malonate (9.5 g, 50 mol%) were added, and the temperature was adjusted to 70 ° C. Subsequently, a 30 mass% methanol solution (0.05 g) of sodium methylate was added to a four-necked flask, and reacted at 70 ° C. for 3 hours. Next, 3,5-dimethylpyrazole (5.7 g, 50 mol%) was added to the four-necked flask and held for 2 hours. Next, the NCO content of 0.0% by mass was confirmed, n-butanol (7.2 g) was added, and the mixture was held at 70 ° C. for 2 hours to obtain a blocked isocyanate composition 6.
The calculated NCO content of the obtained blocked isocyanate composition 6 was 13.9% by mass. Further, the evaluation of the degree of viscosity reduction was ◯, the evaluation of crystallization was ◎, the low-temperature curability evaluation was ◎, and the storage stability evaluation of the paint was ◯. These 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 tube was placed in a nitrogen atmosphere, and HDI polyisocyanate (manufactured by Asahi Kasei Corporation, TKA-100). ) (10.0 g) and butyl acetate (6.3 g) were added and reacted at 120 ° C. for 3 hours. Next, the temperature was 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. Then, NCO content rate 0.0 mass% was confirmed, and the blocked isocyanate composition 15 was obtained.
The calculated NCO content of the obtained blocked isocyanate composition 11 was 10.3% by mass. Further, the evaluation of the degree of viscosity reduction was x, the evaluation of crystallization was ◎, the evaluation of low-temperature curability was ◎, and the storage stability evaluation of the paint was ◯. These 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 HDI polyisocyanate, the blocking agent, the used mass of the diluent, and the addition ratio of the blocking agent were as shown in Table 2. Was used to produce a blocked isocyanate composition 16. Table 2 shows 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.

The blocked isocyanate compositions obtained in Examples 1 to 12 had low viscosity, and were excellent in low crystallinity, low-temperature curability, and coating storage stability.
On the other hand, the blocked isocyanate composition obtained in Comparative Example 1 was remarkably crystallized, so that a coating composition could not be prepared, and the low temperature curability and the coating storage stability could not be evaluated.
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 excellent low crystallinity and low temperature curability. In addition, 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. In addition, the one-component coating composition using the blocked isocyanate composition as a curing agent is a primer or top intermediate coating for metals such as steel plates and surface-treated steel plates, and materials such as plastics, wood, films, and inorganic materials. It can be used as a paint. In addition, a one-component coating composition using the blocked isocyanate composition as a curing agent imparts heat resistance, cosmetic properties (surface smoothness, sharpness), etc. to pre-coated metal including rust-proof steel plates and automobile coating. 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 raw material for adhesives, pressure-sensitive adhesives, elastomers, foams, surface treatment agents and the like.

Claims (5)

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 types of blocking agents.

In general formula (I), a plurality of Y ¹ are each independently a single bond or a divalent divalent having 1 to 20 carbon atoms that may contain at least one selected from the group consisting of an ester structure and an ether structure. It is a hydrocarbon group. A plurality of Y ¹ may be the same or different. R ¹ is a hydrogen atom or a monovalent hydrocarbon group having 1 to 12 carbon atoms.   The blocked isocyanate composition according to claim 1, wherein the at least two types of blocking agents include at least one selected from the group consisting of amine compounds and active methylene compounds, and pyrazole compounds.   3. The blocked isocyanate composition according to claim 1, wherein a ratio of an isocyanate group blocked with the pyrazole compound out of the isocyanate group blocked with the blocking agent is 20 mol% to 80 mol%.   The one-pack type coating composition containing the blocked isocyanate composition as described in any one of Claims 1-3, and a polyol.   A coating film obtained by curing the one-component coating composition according to claim 4.