JP2022041366A - Blocked isocyanate composition, coating composition, and coating film - Google Patents

Abstract

To provide a blocked isocyanate composition which is excellent in curability while maintaining good blocking resistance and is excellent in gloss and image clarity when formed into a coating film.SOLUTION: The blocked isocyanate composition contains a blocked isocyanate derived from: a triisocyanate compound represented by the following general formula (I); and a blocking agent containing an amine-based compound. The content of the amine-based compound is 80 mol% or more and 100 mol% or less based on the total molar amount of the blocking agent. (In the general formula (I), a plurality of Y1's each independently represent a C1-20 divalent hydrocarbon group; and R1 represents a hydrogen atom or a C1-12 monovalent hydrocarbon group.)SELECTED DRAWING: None

Description

The present invention relates to blocked isocyanate compositions, coating compositions and coatings.

In recent years, in the paint and painting industry, users have become more aware of environmental issues. Against this background, the importance of environmentally friendly paint technology is increasing, and the shift from solvent-based paints to high-solid, water-based, and powder paints is progressing. Since powder paint does not use any organic solvent, there is no risk of fire or poisoning. In addition, since the paint can be collected and reused, there is little environmental pollution, and therefore, the demand for powdering polyurethane paint is increasing.

Current polyurethane powder paints use a blocking agent such as ε-caprolactum to form a polyester polyol as a main agent and an isocyanate group of a polyisocyanate derived from isophorone diisocyanate (hereinafter, may be referred to as "IPDI") as a curing agent. Blocked block polyisocyanates (see, for example, Patent Document 1 and the like) are melt-mixed with an extruder at a temperature at which the blocking agent does not dissociate, and then pulverized to obtain a paint.

Further, for example, in Patent Documents 2 and 3, polyisocyanate derived from IPDI is used, or in Patent Document 4, tolylene diisocyanate or hexamethylene diisocyanate (hereinafter, may be referred to as "HDI"). ) Is used and a blocking agent is not used, and a polyuretdione type curing agent is disclosed. These polyuretdione-type curing agents are used as curing agents for powder coating materials because the uretdione groups formed of 2 mol of isocyanate groups dissociate into 2 mol of isocyanate groups again at the time of coating baking and can react with the polyol. be able to.

Special Publication No. 61-31744 Special Publication No. 64-5627 Special Fair 2-16332 Gazette Special Publication No. 57-46447

A curing agent for powder coating materials is required to have both curability, blocking resistance and coating film appearance.
However, although the curing agents for powder coating materials described in Patent Documents 1 to 4 have excellent blocking resistance, the curing property is insufficient, and there are problems in the appearance of the coating film such as the gloss and image quality of the cured coating film. ..

INDUSTRIAL APPLICABILITY The present invention has been made in view of the above circumstances, and provides a blocked isocyanate composition having excellent curability, gloss and image quality when used as a coating film, while maintaining good blocking resistance. do. Further, a coating composition and a coating film using the blocked isocyanate composition are provided.

That is, the present invention includes the following aspects.
(1) Contains a blocked isocyanate derived from a triisocyanate compound represented by the following general formula (I), a blocking agent containing an amine-based compound, and the like.
A blocked isocyanate composition in which the content of the amine compound is 80 mol% or more and 100 mol% or less with respect to the total molar amount of the blocking agent.

(In the general formula (I), a plurality of Y ^1s are independently divalent hydrocarbon groups having 1 or more and 20 or less carbon atoms. R ¹ is a hydrogen atom or a monovalent group having 1 or more and 12 or less carbon atoms. It is a hydrocarbon group.)

(2) The blocked isocyanate composition according to (1), wherein the content of the amine compound is 87 mol% or more and 100 mol% or less with respect to the total molar amount of the blocking agent.
(3) The blocked isocyanate composition according to (1) or (2), wherein the amine compound is a secondary amine compound.
(4) The blocked isocyanate composition according to any one of (1) to (3), which is in the form of powder.
(5) A coating composition comprising the blocked isocyanate composition according to any one of (1) to (4) and an active hydrogen compound.
(6) A coating film obtained by curing the coating composition according to (5).

According to the blocked isocyanate composition of the above aspect, it is possible to provide a blocked isocyanate composition having excellent curability and excellent gloss and image quality when used as a coating film while maintaining good blocking resistance. The coating composition of the above aspect contains the blocked isocyanate composition and is excellent in gloss and image quality when formed into a coating film. The coating film of the above aspect is obtained by curing the coating composition, and is excellent in gloss and image quality.

Hereinafter, embodiments 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 appropriately modified and carried out within the scope of the gist thereof.

≪Blocked isocyanate composition≫
The blocked isocyanate composition of the present embodiment is composed of a triisocyanate compound represented by the following general formula (I) (hereinafter, may be referred to as “triisocyanate compound (I)”) and a blocking agent containing an amine compound. Contains induced blocked isocyanates.

(In the general formula (I), a plurality of Y ^1s are independently divalent hydrocarbon groups having 1 or more and 20 or less carbon atoms. R ¹ is a hydrogen atom or a monovalent group having 1 or more and 12 or less carbon atoms. It is a hydrocarbon group.)

In the blocked isocyanate composition of the present embodiment, the content of the amine-based compound with respect to the total molar amount of the blocking agent is 80 mol% or more and 100 mol% or less, preferably 87 mol% or more and 100 mol% or less, and 90 mol%. More than 100 mol% is more preferable, 95 mol% or more and 100 mol% or less is further preferable, 97 mol% or more and 100 mol% or less is particularly preferable, and 100 mol% is most preferable. When the content of the amine compound with respect to the total molar amount of the blocking agent is at least the above lower limit value, a blocked isocyanate composition having excellent gloss and image quality when formed into a coating film can be obtained.
The content of the amine compound with respect to the total molar amount of the blocking agent is, for example, a value obtained by dividing the compounding amount (molar amount) of the amine compound used at the time of production by the total molar amount (molar amount) of the blocking agent and multiplying by 100. It can be calculated by Alternatively, it can be calculated from the area value of the peak derived from each blocking agent, for example, by ¹ H-NMR.

By having the above-mentioned structure, the blocked isocyanate composition of the present embodiment can obtain a coating film having excellent curability and excellent gloss and image quality while maintaining good blocking resistance.

The form of the blocked isocyanate composition of the present embodiment is not particularly limited, but is preferably in the form of powder. That is, when the blocked isocyanate composition of the present embodiment is in the form of powder, it can also be said to be a powder-like curing agent composition for paints.

Next, the constituent components of the blocked isocyanate composition of the present embodiment will be described in detail below.

<Blocked isocyanate>
The blocked isocyanate is derived from the triisocyanate compound (I) and the blocking agent containing an amine-based compound, that is, the reaction between the triisocyanate compound (I) and the blocking agent containing an amine-based compound. It is a thing. Further, in the blocked isocyanate, at least a part of the isocyanate groups in the triisocyanate compound (I) are blocked with a blocking agent containing an amine compound.

[Triisocyanate compound (I)]
The triisocyanate compound (I) is a compound represented by the following general formula (I).

(In the general formula (I), a plurality of Y ^1s are independently divalent hydrocarbon groups having 1 or more and 20 or less carbon atoms. R ¹ is a hydrogen atom or a monovalent group having 1 or more and 12 or less carbon atoms. It is a hydrocarbon group.)

(Y ¹ )
In the general formula (I), each of the plurality of Y ^1s is a divalent hydrocarbon group having 1 or more and 20 or less carbon atoms independently. The plurality of Y ^1s may be the same or different from each other.

The divalent hydrocarbon group having ¹ or more carbon atoms and 20 or less carbon atoms in Y1 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 an alkanediyl group (alkylene group) and an alkylidene group.
Examples of the cyclic aliphatic group include a cycloalkylene group and the like.
Examples of the aromatic group include an arylene group such as a phenylene group.
Among these, the hydrocarbon group preferably has an alkylene group having 1 or more and 6 or less carbon atoms, and specific examples thereof include a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group and a hexylene group. Be done.

(R ¹ )
R ¹ is a hydrogen atom or a monovalent hydrocarbon group having 1 or more and 12 or less carbon atoms.
The monovalent hydrocarbon group having 1 or more and 12 or less carbon atoms 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 ^R1 .

When at least ^one of the plurality of Y1s has at least one selected from the group consisting of an aliphatic group and an aromatic group, a preferable triisocyanate compound (I) is, for example, Japanese Patent Publication No. 63-15264. 4-Isocyanate Methyl-1,8-octamethylene diisocyanate (hereinafter referred to as "NTI", molecular weight 251) disclosed in (Reference 1), disclosed in JP-A-57-198760 (Reference 2). Examples thereof include 1,3,6-hexamethylene triisocyanate (hereinafter referred to as “HTI”, molecular weight 209).

The triisocyanate compound (I) can be obtained by isocyanateming an amine such as an amino acid derivative, an ether amine and an alkyl triamine.
Examples of the amino acid derivative include triisocyanatononane (4-aminomethyl-1,8-octanediamine) and the like. These alkyl triamines are triamines and can be made into triisocyanate compounds by phosgenation of the amines and the like.

The lower limit of the molecular weight of the triisocyanate compound (I) is preferably 139, more preferably 150, still more preferably 180, and particularly preferably 200. On the other hand, the upper limit of the molecular weight of the triisocyanate compound (I) is preferably 1000, more preferably 800, further preferably 600, and particularly preferably 400.
That is, the molecular weight of the triisocyanate compound (I) 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 200 or more and 400 or less. Is particularly preferred.
When the molecular weight of the triisocyanate compound (I) is at least the above lower limit value, the blocking resistance tends to be better, while when it is at least the above upper limit value, the compatibility with the main agent can be improved. can.

[Other isocyanate compounds]
The blocked isocyanate composition of the present embodiment has the effect of the blocked isocyanate composition of the present embodiment in addition to the blocked isocyanate derived from the triisocyanate compound (I) and the blocking agent containing an amine compound. Blocked isocyanate derived from other isocyanate compounds and blocking agents may be further contained as long as it is not impaired.

Examples of the other isocyanate compound include a triisocyanate compound other than the above triisocyanate compound (I), a diisocyanate having an aliphatic group, an alicyclic group, or an aromatic group, or a polyisocyanate.
Examples of the triisocyanate compound other than the triisocyanate compound (I) include lysine triisocyanate (LTI) and the like.
Examples of the diisocyanate having an aliphatic group include tetramethylene diisocyanate (TMDI), pentamethylene diisocyanate (PDI), hexamethylene diisocyanate (HDI), 2,2,4-trimethylhexane-1,6-diisocyanate and 2-methyl. Examples thereof include pentane-1,5-diisocyanate (MPDI) and lysine diisocyanate (LDI).
Examples of the diisocyanate having an alicyclic group include 1,3-bis (isocyanatomethyl) -cyclohexane (1,3-H6-XDI), 3 (4) -isocyanatomethyl-1-methyl-cyclohexylisoa. Nate (IMCI), isophorone diisocyanate (IPDI), bis (isocyanatomethyl) -norbornane (NBDI) and the like can be mentioned.
Examples of the diisocyanate having an aromatic group include 1,3-bis (isocyanatomethyl) -benzene, 1,3-bis (2-isocyanatopropyl-2) benzene, and 4,4'-dicyclohexylmethane diisocyanate (H12MDI). ) Etc. can be mentioned.
Among them, as the diisocyanate, HDI or IPDI is preferable because of its mechanical properties and easy industrial availability.
As the polyisocyanate, a triisocyanate compound (I), a triisocyanate compound other than the triisocyanate compound (I), or a diisocyanate is polymerized, and an isocyanurate structure, a bullet structure, a uretdione structure, or an iminooxadiazinedione structure is contained in the molecule. , Polyisocyanate compounds containing at least one selected from the group consisting of urethane structure and allophanate structure and the like.
These other isocyanate compounds may be used alone or in combination of two or more.

[Blocking agent]
The blocking agent may be a heat-dissociating blocking agent and may contain an amine-based compound.
The term "heat dissociability" as used herein means the property that the blocking agent bonded to the isocyanate group is dissociated by heating and the isocyanate group is regenerated. The temperature required for dissociation varies depending on the structure of the blocking agent, but is, for example, 40 ° C. or higher and 300 ° C. or lower.

(Amine compound)
Since the amine compound has high volatility and low toxicity as compared with the conventional blocking agent, it can be suitably used as a blocking agent.
The amine compound is not particularly limited, and is preferably a primary amine compound or a secondary amine compound from the viewpoint of reactivity, and a secondary amine from the viewpoint of blocking resistance of the blocked isocyanate composition. More preferably, it is a compound.

Examples of the primary amine compound include aniline, n-butylamine, hexylamine, 2-ethylhexylamine, and the like.
Examples of the secondary amine compound include carbazole, diisopropylamine, di-n-propylamine, di-n-butylamine, di-n-octylamine, tert-butylbenzylamine, diphenylamine and the like.

These amine compounds may be used alone or in combination of two or more.

(Other blocking agents)
As the blocking agent, in addition to the above-mentioned amine-based compound, other blocking agents may be used in combination so that the content of the amine-based compound is within the above-mentioned range.

Examples of other blocking agents include (1) pyrazole-based compounds, (2) oxime-based compounds, (3) lactam-based compounds, (4) active methylene-based compounds, (5) alcohol-based compounds, and (6) imidazole-based compounds. (7) Examples thereof include triazole compounds. More specific examples of other blocking agents include those shown below.
(1) Pyrazole-based compounds: pyrazole, 3-methylpyrazole, 3,5-dimethylpyrazole and the like.
(2) Oxime-based compounds: formaldehyde, acetaldoxime, acetoxime, methylethylketooxime, cyclohexanone oxime, acetophenone oxime and the like.
(3) Lactam compounds: ε-caprolactam and the like.
(4) Active methylene compound: dimethyl malonate, diethyl malonate, diisopropyl malonate, di-tert-butyl malonic acid, methyl acetoacetate, ethyl acetoacetate, acetylacetone and the like.
(5) Alcohol compounds: methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, sec-butanol, 2-ethyl-1-hexanol, cyclohexanol, 2-methoxyethanol, 2-ethoxyethanol, 2- Butoxyethanol, benzyl alcohol, trifluoroethanol, hexafluoro-2-propanol, 2-methyl-1-propanol, 1-dodecanol, 1-octadecanol, phenol, tert-butanol and the like.
(6) Imidazole compounds: imidazole, 2-methylimidazole and the like.
(7) Triazole compounds: 1,2,4-triazole, 1,2,3-triazole and the like.

Among them, as other blocking agents to be combined with the above amine compounds, pyrazole compounds or alcohol compounds are preferable because they have better blocking resistance, and alcohol compounds are preferable because they have high volatility and relatively low toxicity. More preferred.

<Manufacturing method of blocked isocyanate composition>
In the blocked isocyanate composition of the present embodiment, for example, the above-mentioned triisocyanate compound (I) is reacted with a blocking agent containing an amine-based compound to obtain an isocyanate group of the triisocyanate compound (I) as an amine-based compound. Examples thereof include a method of blocking with a blocking agent containing (hereinafter, may be referred to as “blocking reaction”).
In the blocking reaction, all or part of the isocyanate group of the triisocyanate compound (I) can be blocked.
When blocking all the isocyanate groups of the triisocyanate compound (I), the ratio of the number of moles of the blocking agent to the number of moles of the isocyanate groups of the triisocyanate compound (I) (the number of moles of the blocking agent / the molar number of the isocyanate groups). The number) is preferably 1.0 or more and 1.5 or less.
When the blocking agent is blended in the above ratio, the excess or unreacted blocking agent remains.

The blocking reaction may be carried out without a solvent, or if necessary, an organic solvent having no reactivity with an isocyanate group may be used.
The organic solvent is not particularly limited, and specific examples thereof include those shown below.
(I) An aliphatic hydrocarbon solvent such as hexane, heptane, and octane.
(Ii) An alicyclic hydrocarbon solvent such as cyclohexane or methylcyclohexane.
(Iii) A ketone solvent such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone and the like.
(Iv) Ester-based solvent such as methyl acetate, ethyl acetate, butyl acetate and isobutyl acetate.
(V) Aromatic solvents such as toluene, xylene, diethylbenzene, mesitylene, anisole and chlorobenzene.
(Vi) Glycol-based solvent such as ethylene glycol monoethyl ether acetate, 3-methyl-3-methoxybutyl acetate, and propylene glycol monomethyl ether acetate.
(Vii) Ether-based solvent such as diethyl ether, tetrahydrofuran and dioxane.
(Viii) Halogenated hydrocarbon solvents such as dichloromethane, 1,2-dichloroethane and chloroform.
(Ix) A pyrrolidone-based solvent such as N-methyl-2-pyrrolidone.
(X) An amide-based solvent such as N, N-dimethylacetamide and N, N-dimethylformamide.
(Xi) A sulfoxide-based solvent such as dimethyl sulfoxide.
(Xii) A lactone-based solvent such as γ-butyrolactone.
(Xiii) Amine-based solvent such as morpholin.

These organic solvents may be used alone or as a mixture of two or more. In addition, the organic solvent can be removed after the reaction.

Further, a catalyst may be used in the blocking reaction. Examples of the catalyst include, but are not limited to, organic metal salts such as tin, zinc and lead; tertiary amine compounds; and alkali metal alcoholates such as sodium.

The blocking reaction can generally be carried out at −20 ° C. or higher and 150 ° C. or lower, preferably 0 ° C. or higher and 100 ° C. or lower, and more preferably 10 ° C. or higher and 80 ° C. or lower. When the temperature of the blocking reaction is at least the above lower limit value, the reaction rate can be further increased, and when it is at least the above upper limit value, the side reaction can be further suppressed.

After the blocking reaction, a neutralization treatment may be performed by adding an acidic compound or the like.
As the acidic compound, an inorganic acid may be used or an organic acid may be used. Examples of the inorganic acid include hydrochloric acid, phosphoric acid, phosphoric acid and the like. Examples of the organic acid include methanesulfonic acid, p-toluenesulfonic acid, dioctylphthalate, dibutylphthalate and the like.

<Physical characteristics of blocked isocyanate composition>
The blocked isocyanate composition of the present embodiment preferably has an effective isocyanate group (NCO) content of 10% by mass or more and 30% by mass or less, and more preferably 12% by mass or more and 27% by mass or less.

The "effective isocyanate group (NCO) content" referred to here is a quantification of the amount of blocked isocyanate groups present in the blocked isocyanate composition after the blocking reaction and which may be involved in the crosslinking reaction. It is expressed in terms of mass% of isocyanate groups.
The effective NCO content can be calculated, for example, by the following formula. In the following formula, "NCO%" is the isocyanate group content of the triisocyanate compound (I).

(Effective NCO content (% by mass))
= [(Content content of solid content (mass%) of blocked isocyanate composition) x {(mass of triisocyanate compound (I) used in blocking reaction) x NCO%}] / (blocked isocyanate after blocking reaction) Composition mass)

≪Paint composition≫
The coating composition of the present embodiment contains the above-mentioned blocked isocyanate composition and an active hydrogen compound.

By containing the above-mentioned blocked isocyanate composition as a curing agent component in the coating composition of the present embodiment, a coating film having excellent gloss and image quality can be obtained.

<Active hydrogen compound>
The active hydrogen compound is not particularly limited, but specifically, it is a compound in which two or more active hydrogens are bonded in the molecule, and examples thereof include a polyol compound, a polyamine compound, and a polythiol compound. Above all, from the viewpoint of toughness, the active hydrogen compound is preferably a polyol compound. In particular, when a polyol compound is used as the active hydrogen compound, the coating composition is also referred to as a polyurethane coating composition.

[Polyol compound]
The polyol compound is not particularly limited, and specific examples thereof include polyester polyols, acrylic polyols, polyether polyols, polyolefin polyols, fluorine polyols, polycarbonate polyols, epoxy resins, urethane polyols and the like. Above all, one or more polyols selected from the group consisting of liquid or solid polyester polyols, acrylic polyols, and fluorine polyols at room temperature (temperature of about 20 ° C. or higher and 30 ° C. or lower) are preferable.

Examples of the polyester polyol include, but are not limited to, products obtained by a condensation reaction between a dibasic acid alone or a mixture and a polyhydric alcohol alone or a mixture.
The dibasic acid is not particularly limited, but is at least one selected from the group consisting of carboxylic acids such as succinic acid, adipic acid, sebacic acid, dimer acid, maleic anhydride, phthalic acid anhydride, isophthalic acid, and terephthalic acid. Species dibasic acid can be mentioned.
The polyhydric alcohol is not particularly limited, and examples thereof include at least one polyhydric alcohol selected from the group consisting of ethylene glycol, propylene glycol, diethylene glycol, neopentyl glycol, trimethylolpropane, and glycerin.
Alternatively, as the polyester polyol, for example, polycaprolactone obtained by ring-opening polymerization of ε-caprolactone using a polyhydric alcohol, or esters obtained from an aliphatic hydrocarbon compound having a hydroxyl group and a polyhydric alcohol. And so on.

The acrylic polyol is not particularly limited, but for example, an ethylenically unsaturated bond-containing monomer having a hydroxyl group alone or a mixture thereof and another ethylenically unsaturated bond-containing monomer copolymerizable therewith alone or a mixture thereof. Examples thereof include those obtained by copolymerizing with a mixture.
The ethylenically unsaturated bond-containing monomer having a hydroxyl group is not particularly limited, and for example, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxy methacrylate. Examples include butyl.
The other ethylenically unsaturated bond-containing monomer copolymerizable with the ethylenically unsaturated bond-containing monomer having a hydroxyl group is not particularly limited, and is, for example, an acrylic acid ester, a methacrylic acid ester, or an unsaturated carboxylic acid. , Unsaturated amides, vinyl monomers, vinyl monomers having a hydrolyzable silyl group.
Examples of the acrylic acid ester include methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, -n-butyl acrylate, isobutyl acrylate, -n-hexyl acrylate, cyclohexyl acrylate, and -2 acrylate. -Ethylhexyl, lauryl acrylate, benzyl acrylate, phenyl acrylate and the like can be mentioned.
Examples of the methacrylic acid ester include methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, -n-butyl methacrylate, isobutyl methacrylate, -n-hexyl methacrylate, cyclohexyl methacrylate, and -2 methacrylic acid. -Ethylhexyl, lauryl methacrylate, benzyl methacrylate, phenyl methacrylate and the like can be mentioned.
Examples of unsaturated carboxylic acids include acrylic acid, methacrylic acid, maleic acid, itaconic acid and the like.
Examples of unsaturated amides include acrylamide, methacrylamide, N, N-methylenebisacrylamide, diacetoneacrylamide, diacetonemethacrylamide, maleic acid amide, maleimide and the like.
Examples of the vinyl-based monomer include glycidyl methacrylate, styrene, vinyltoluene, vinyl acetate, acrylonitrile, dibutyl fumarate and the like.
Examples of the vinyl-based monomer having a hydrolyzable silyl group include vinyltrimethoxysilane, vinylmethyldimethoxysilane, γ- (meth) acryloxypropyltrimethoxysilane, and the like.

The polyether polyol is not particularly limited, but for example, an alkali metal hydroxide or a strongly basic catalyst is used to add the alkylene oxide alone or the mixture to the polyhydric alcohol alone or the mixture. Examples thereof include a obtained polyether polyol, a polyether polyol obtained by reacting a polyamine compound with an alkylene oxide, and a so-called polymer polyol obtained by polymerizing acrylamide or the like using the above-mentioned polyether polyol as a medium.
Examples of the alkali metal include lithium, sodium, potassium and the like.
Examples of the strongly basic catalyst include alcoholates, alkylamines and the like.
Examples of the polyhydric alcohol include the same as those exemplified in the above polyester polyol. Further, as the polyhydric alcohol, non-saccharides, sugar alcohol-based compounds, monosaccharides, disaccharides, trisaccharides, tetrasaccharides and the like may be further used. Examples of non-saccharides include diglycerin, ditrimethylolpropane, pentaerythritol, dipentaerythritol and the like. Examples of the sugar alcohol compound include erythritol, D-threitol, L-arabinitol, ribitol, xylitol, sorbitol, mannitol, galactitol, ramnitol and the like. Examples of the monosaccharide include arabinose, ribose, xylose, glucose, mannose, galactose, fructose, sorbose, rhamnose, fucose, ribodesource and the like. Examples of the disaccharide include trehalose, sucrose, maltose, cellobiose, gentiobiose, lactose, melibiose and the like. Examples of the trisaccharide include raffinose, gentianose, meletitos and the like. Examples of the tetrasaccharide include stachyose and the like.
Examples of the alkylene oxide include ethylene oxide, propylene oxide, butylene oxide, cyclohexene oxide, styrene oxide and the like.
Examples of the polyamine compound include ethylenediamines.

Examples of the polyolefin polyol include hydroxyl-terminated polybutadiene, polyisoprene terminally hydroxylated, and hydrogenated additives thereof.

The fluorine polyol is a polyol containing fluorine in the molecule, and for example, fluoro is disclosed in JP-A-57-34107 (Reference 3) and JP-A-61-275311 (Reference 4). Examples thereof include copolymers of olefins, cyclovinyl ethers, hydroxyalkyl vinyl ethers, monocarboxylic acid vinyl esters and the like.

The polycarbonate polyol is not particularly limited, and examples thereof include a small molecule carbonate compound or a polycarbonate polyol obtained by polycondensing the small molecule carbonate compound and a polyhydric alcohol. Examples of the polyhydric alcohol include the same as those exemplified in the above-mentioned "polyester polyol".
Examples of the small molecule carbonate compound include dialkyl carbonate, alkylene carbonate, diaryl carbonate and the like.
Examples of the dialkyl carbonate include dimethyl carbonate and the like.
Examples of the alkylene carbonate include ethylene carbonate and the like.
Examples of the diaryl carbonate include diphenyl carbonate and the like.

The epoxy resin is not particularly limited, but specifically, for example, a novolak type epoxy resin, a glycidyl ether type epoxy resin, a glycol ether type epoxy resin, an aliphatic unsaturated compound epoxy type resin, an epoxy type fatty acid ester, and many. Valuable carboxylic acid ester type epoxy resin, aminoglycidyl type epoxy resin, β-methylepiclo type epoxy resin, cyclic oxylan type epoxy resin, halogen type epoxy resin, resorcin type epoxy resin and the like can be mentioned.

The urethane polyol is a polymer produced by repeating an addition reaction between aromatic, aliphatic or alicyclic diisocyanates and a compound having active hydrogen, and has a urethane bond in the polymer, and has urethane bonds in the polymer side chains and ends. Examples thereof include those having a hydroxyl group.

In the coating composition of the present embodiment, the molar equivalent ratio of the effective isocyanate group to the hydroxyl group of the polyol compound ([effective isocyanate group] / [hydroxyl group]) is usually 1/10 or more and 10/1 or less. Can be set. The term "effective isocyanate group (effective NCO)" as used herein means an isocyanate group present in the blocked isocyanate composition that can participate in the crosslinking reaction.

The hydroxyl value of the polyol compound is preferably 20 mgKOH / g or more and 200 mgKOH / g or less, more preferably 30 mgKOH / g or more and 200 mgKOH / g or less, and even more preferably 40 mgKOH / g or more and 180 mgKOH / g or less. When the hydroxyl value of the polyol compound is at least the above lower limit, it is possible to prevent the crosslink density from decreasing and to more sufficiently achieve the desired physical properties. On the other hand, when the hydroxyl value of the polyol compound is not more than the above upper limit, it is possible to suppress an excessive increase in the crosslink density and maintain a higher degree of mechanical properties of the coating film.

The acid value of the polyol compound is preferably 1 mgKOH / g or more and 60 mgKOH / g or less, more preferably 2 mgKOH / g or more and 50 mgKOH / g or less, and further preferably 4 mgKOH / g or more and 40 mgKOH / g or less. , 6 mgKOH / g or more and 30 mgKOH / g or less is particularly preferable.
When the acid value of the polyol compound is at least the above lower limit, the storage stability can be further improved. On the other hand, when the acid value is not more than the above upper limit value, the water resistance of the obtained coating film can be further improved.
When the polyol compound is a fluorine polyol, the acid value of the fluorine polyol is preferably 10 mgKOH / g or less.

<Other additives>
In addition to the blocked isocyanate composition and the active hydrogen compound, the coating composition of the present embodiment may contain, for example, a curing accelerating catalyst, an antioxidant, an ultraviolet absorber, a light stabilizer, a pigment, depending on the purpose and application. Various additives such as leveling agents, plasticizers, rheology control agents, and surfactants can be further contained.

The curing acceleration catalyst is not particularly limited, and specific examples thereof include tin compounds, zinc compounds, titanium compounds, cobalt compounds, bismuth compounds, zirconium compounds, and amine compounds. Examples of the tin-based compound include dibutyltin dilaurate, dibutyltin diacetate, dioctyltin dilaurate, dimethyltindineodecanoate, and bis (2-ethylhexanoic acid) tin. Examples of the zinc compound include zinc 2-ethylhexanoate and zinc naphthenate. Examples of the titanium compound include titanium 2-ethylhexanoate, titanium diisopropoxybis (ethylacetonate) and the like. Examples of the cobalt compound include cobalt 2-ethylhexanoate and cobalt naphthenate. Examples of the bismuth compound include bismuth 2-ethylhexanoate and bismuth naphthenate. Examples of the zirconium compound include zirconium tetraacetylacetonate, zirconyl 2-ethylhexanoate, zirconyl naphthenate and the like.

<Manufacturing method of paint composition>
When the coating composition of the present embodiment is a powdery coating composition, it can be produced, for example, by using the method shown below.
First, an active hydrogen compound (preferably a polyol compound) and the above-mentioned blocked isocyanate composition are kneaded together with the above-mentioned various additives in a temperature range of 80 ° C. or higher and 140 ° C. or lower by an extruder or the like, if necessary. do. The kneaded product can be pulverized by a pulverizer, and the obtained pulverized product can be used as a powdery coating composition. The average particle size of the obtained powdery coating composition can be adjusted to, for example, 10 μm or more and 200 μm or less.

Alternatively, in the case of producing a solvent-based resin composition, first, the above-mentioned various additives are added to the active hydrogen compound or the solvent diluted product thereof, if necessary. Then, the above-mentioned 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 resin composition can be obtained by stirring by hand or using a stirring device such as a magella.

≪Coating film≫
The coating film of the present embodiment is obtained by curing the above-mentioned coating composition. The coating film of the present embodiment is excellent in appearance such as gloss and image quality.

The coating film of the present embodiment can be produced, for example, by using the method shown below.
The coating composition (preferably a powdery coating composition) is applied to the surface of the coated object by a commonly used method such as spray coating, roll coating, curtain flow coating, and electrostatic coating. Then, a uniform coating film is formed on the coated body by heat baking at a temperature of 160 ° C. or higher.

The coated body mainly includes a metal plate. Examples of the metal plate include a stainless steel plate, an aluminum plate, a titanium plate, a cold-rolled steel plate, a galvanized steel plate, a chrome-plated steel plate, an aluminum-plated steel plate, a nickel-plated steel plate, and the like. Further, if necessary, the surface of these metal plates may be cleaned by alkaline degreasing or the like, or the metal surface may be subjected to chemical conversion treatment in order to improve the adhesion to the coating film.
Further, the metal plate may be a metal molded product which has been predeterminedly molded in advance. Alternatively, if necessary, an undercoat layer may be formed on the metal surface in advance. The coating film thickness of the undercoat layer is preferably 100 μm or less.

In the above-mentioned coating composition, the blocking agent released at the time of coating and baking on a metal plate has high volatility and hardly remains in the furnace. Further, the obtained coating film is excellent in weather resistance, impact resistance, surface gloss and the like. Therefore, the pre-coated metal plate provided with the coating film obtained by curing the above-mentioned coating composition is, for example, an outer box such as a refrigerator, a washing machine, an air conditioner, a microwave oven, a door, and other household electric appliances such as a net fence. Building materials such as pipe fences and road materials such as guard rails; automobile parts such as wipers, coil springs and bumpers and automobile bodies; parts and bodies of special equipment such as civil engineering equipment and cultivators; office furniture such as steel furniture and steel shelves; It can be suitably used for electrical equipment parts such as electric boards, switch boards, radiators, and transformers. Due to its wide range of applications, it is not limited to those listed above.

Examples of the coated body other than the metal plate include concrete products, wood products, plastic products and the like.

Hereinafter, the present invention will be described in more detail based on Examples and Comparative Examples, but the present invention is not limited to the following Examples.

≪Evaluation items≫
Measurement of each physical property 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 methods shown below. And each evaluation was performed.

<Measurement method of physical properties>
[Physical characteristics 1]
(Isocyanate group (NCO) content)
The NCO content (% by mass) of the triisocyanate compound was determined by neutralizing the isocyanate group in the measurement sample with an excess of 2N amine and then back titrating with 1N hydrochloric acid.

[Physical characteristics 2]
(Effective isocyanate group (NCO) content)
The effective NCO content of the blocked isocyanate composition was calculated using the following formula.

(Effective NCO content)
= {(Isocyanate compound content) x (NCO content of isocyanate compound)} / (Total mass of blocked isocyanate composition)

<Evaluation method>
[Evaluation 1]
(Blocking resistance)
The solid blocked isocyanate composition was pulverized into a uniform powder, placed in a glass bottle, and then allowed to stand in an oven at 40 ° C. for 10 days. After that, it was taken out from the oven and the condition was visually confirmed. The evaluation criteria are as follows.

(Evaluation criteria for blocking resistance)
◎: No change ○: Slightly blocking △: Almost blocking ×: Completely blocking

[Manufacturing of paint composition]
A polyester polyol (trade name "SETALUX 1152 SS-60" manufactured by Allnex) and each blocked isocyanate composition were blended so as to have a molar equivalent ratio of an effective isocyanate group / hydroxyl group of 1.0. Next, a tin catalyst (trade name "FASCAT4200" manufactured by PMC ORGANOMETARIC) was added in an amount of 0.4 parts by mass in terms of tin mass with respect to the mass of the paint solid content, and then N, N-dimethylformamide (DMF) was added to the paint solid content. Was prepared to be 50% by mass, and each coating composition was obtained.

[Evaluation 2]
(Cursability (gel fraction))
The prepared coating composition was coated on an aluminum plate with a dry film thickness of 40 μm and baked at 180 ° C. for 30 minutes to obtain a coating film. The obtained coating film was peeled off from an aluminum plate and immersed in acetone at 23 ° C. for 24 hours, and then the residual film ratio was calculated and used as the gel fraction. The evaluation criteria for curability are as follows.

(Evaluation criteria for curability)
⊚: Gel fraction is 90% by mass or more ○: Gel fraction is 85% by mass or more and less than 90% by mass Δ: Gel fraction is 80% by mass or more and less than 85% by mass ×: Gel fraction is less than 80% by mass

[Evaluation 3]
(Gloss of coating film)
The prepared coating composition was coated on an electrodeposition plate with a dry film thickness of 40 μm, and baked at 180 ° C. for 30 minutes to obtain a coating film. The gloss of the prepared coating film was measured at 20 ° using a gloss meter UGV-6P (manufactured by Suga Test Instruments Co., Ltd.). The evaluation criteria are as follows.

(Gloss evaluation criteria)
⊚: Gloss is 90% or more 〇: Gloss is 85% or more and less than 90% △: Gloss is 80% or more and less than 85% ×: Gloss is less than 80%

[Evaluation 4]
(Mapping property of coating film (DOI))
The prepared coating composition was coated on an electrodeposition plate with a dry film thickness of 40 μm, and baked at 180 ° C. for 30 minutes to obtain a coating film. The prepared coating film was measured by Wave-Scan Dual (manufactured by BYK) to obtain a mapability value. The evaluation criteria are as follows.

(DOI evaluation criteria)
⊚: Removability value is 90% or more 〇: Reproducibility value is 85% or more and less than 90% Δ: Reproducibility value is 80% or more and less than 85% ×: Reproducibility value is less than 80%

<Synthesis of triisocyanate compounds>
[Synthesis Example 1]
(NTI synthesis)
In a 4-necked flask equipped with a stirrer, a thermometer, and a gas introduction tube, 1060 g of 4-aminomethyl-1,8-octamethylenediamine (hereinafter sometimes referred to as "triamine") was dissolved in 1500 g of methanol. 1800 mL of 35% by mass concentrated hydrochloric acid was gradually added dropwise to the mixture while cooling. Then, under reduced pressure, methanol and water were removed, concentrated, and dried at 60 ° C./5 mmHg for 24 hours to obtain a white solid triamine hydrochloride. 650 g of the obtained triamine hydrochloride 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 / hour, and the temperature was further increased. Then, when the reaction solution reached 180 ° C., the temperature was maintained as it was, and phosgene was continuously blown for 12 hours. Then, the dissolved phosgene and the solvent were distilled off under reduced pressure, and then vacuum distillation was performed to obtain 420 g of colorless and transparent NTI having a boiling point of 161 ° C. or higher and 163 ° C. or lower / 1.2 mmHg. The NCO content of NTI was 50.0% by mass.

[Synthesis Example 2]
(Synthesis of HTI)
602 g of triethyl 1,3,6-hexamethylenetricarboxylic acid was reacted with hydrazine hydrate by a conventional method to obtain 445 g of trihydrazide 1,3,6-hexamethylenetricarboxylic acid. Then, in the presence of hydrochloric acid, the mixture was reacted with sodium nitrite in an aqueous solution to form the corresponding triazide, extracted with benzene, and the extract was dried. The benzene solution thus obtained was dropped into benzene reflux and thermally decomposed. When the triisocyanate obtained by distilling off benzene was rectified under vacuum, 246 g of a colorless transparent HTI having a boiling point of 152 ° C. or higher and 154 ° C. or lower / 1.3 mmHg was obtained. The NCO content of HTI was 60.1% by mass.

[Example 1]
(Production of Blocked Isocyanate Composition BI-a1)
Nitrogen is substituted in a 4-necked flask equipped with a stirrer, a thermometer, and a gas introduction tube, NTI: 100.0 parts by mass and diisopropylamine: 120.2 parts by mass are added, and the mixture is stirred at 80 ° C. for 6 hours. And reacted. After completion of the reaction, a powdery blocked isocyanate composition BI-a1 was obtained.

[Examples 2 to 15 and Comparative Examples 1 to 2]
(Production of Blocked Isocyanate Compositions BI-a2-BI-a15 and BI-b1-BI-b2)
Each powdered blocked isocyanate composition was obtained by using the same method as in Example 1 except that the types and blending amounts of the isocyanate and the blocking agent were as shown in Tables 1 to 4.

[Comparative Examples 3 to 4]
(Preparation of Blocked Isocyanate Compositions BI-b3 to BI-b4)
A block isocyanate composition BI-b3, a polyisocyanate polyuretdione-type curing agent (Covestro) derived from IPDI, which blocks an ε-caprolactum block-type curing agent of polyisocyanate (trade name "Creelan VPLS2256" of Covestro). The company's trade name "Creelan EF403") was used as the blocked isocyanate composition BI-b4.

The effective NCO content of each of the obtained blocked isocyanate compositions is shown in Tables 1 to 4 below. The evaluation results are shown in Tables 1 to 4 below.

From Tables 1 to 3, the content of the amine compound is 80 mol% or more and 100 mol based on the total molar amount of the blocking agent, which contains the blocked isocyanate derived from the triisocyanate compound and the blocking agent containing the amine compound. % Or less of the blocked isocyanate compositions BI-a1 to BI-a15 (Examples 1 to 15) have excellent curability while maintaining good blocking resistance, and gloss and image quality when used as a coating film. Was excellent.
Further, in the blocked isocyanate compositions BI-a1 to BI-a4 (Examples 1 to 4) in which the types of amine compounds are different, the blocked isocyanate compositions BI-a1 to BI-a3 using the secondary amine compound (implemented). In Examples 1 to 3), the blocking resistance tends to be particularly excellent, and the blocked isocyanate compositions BI-a1 to BI-a2 and BI- in which the alkyl group of the amine compound has 3 or more and 4 or less carbon atoms. In a4 (Examples 1 to 2 and 4), there was a tendency that the image quality when used as a coating film was particularly excellent.
Further, in the blocked isocyanate compositions BI-a1, BI-a6, BI-a13 to BI-a15 (Examples 1, 6, 13 to 15) in which the content of the amine compound is different, the content of the amine compound is 87. When the content is mol% or more, the gloss and image quality of the coating film tend to be superior, and when the content of the amine compound is 90 mol% or more, the glossiness of the coating film is particularly high. An excellent tendency was observed, and further, the content of the amine compound was 100 mol%, so that the image quality when the coating film was formed tended to be particularly excellent.
Further, in the blocked isocyanate compositions BI-a6 to BI-a12 (Examples 1 to 12) in which two types of blocking agents are combined and the types of blocking agents to be combined with the amine-based compound are different, the blocking agents to be combined with the amine-based compound. The blocked isocyanate compositions BI-a6 and BI-a10 (Examples 6 and 10) using the pyrazole-based compound or the alcohol-based compound tended to have particularly excellent blocking resistance.

On the other hand, from Table 4, the blocked isocyanate composition BI-b1 (Comparative Example 1) in which the content of the amine compound is less than 80 mol% with respect to the total molar amount of the blocking agent, the triisocyanate compound, and pyrazole as the blocking agent. The blocked isocyanate composition BI-b2 (Comparative Example 2) containing the system compound and the blocked isocyanate derived from the compound had good blocking resistance, curability and gloss when formed into a coating film, but the coating film was good. The image quality was poor.
Further, the blocked isocyanate composition BI-b3 (Comparative Example 3) made of a polyisocyanate ε-caprolactam block type curing agent derived from IPDI has good blocking resistance, curability and gloss when formed into a coating film. However, the image quality when used as a coating film was poor.
Further, in the blocked isocyanate composition BI-b4 (Comparative Example 4) made of a polyuretdione type curing agent of polyisocyanate derived from IPDI, the blocking resistance was good, but the curability and the coating film were obtained. The gloss and image quality were poor.

According to the blocked isocyanate composition of the present embodiment, it is possible to provide a blocked isocyanate composition having excellent curability and excellent gloss and image quality when used as a coating film while maintaining good blocking resistance. ..

Claims (6)

It contains a blocked isocyanate derived from a triisocyanate compound represented by the following general formula (I), a blocking agent containing an amine-based compound, and the like.
A blocked isocyanate composition in which the content of the amine compound is 80 mol% or more and 100 mol% or less with respect to the total molar amount of the blocking agent.

(In the general formula (I), a plurality of Y ^1s are independently divalent hydrocarbon groups having 1 or more and 20 or less carbon atoms. R ¹ is a hydrogen atom or a monovalent group having 1 or more and 12 or less carbon atoms. It is a hydrocarbon group.) The blocked isocyanate composition according to claim 1, wherein the content of the amine compound with respect to the total molar amount of the blocking agent is 87 mol% or more and 100 mol% or less. The blocked isocyanate composition according to claim 1 or 2, wherein the amine compound is a secondary amine compound. The blocked isocyanate composition according to any one of claims 1 to 3, which is in the form of powder. A coating composition comprising the blocked isocyanate composition according to any one of claims 1 to 4 and an active hydrogen compound. A coating film obtained by curing the coating composition according to claim 5.