JPH11158247A - Curing agent and one-package coating composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a curing agent containing no evaporable blocking agent by selecting a curing agent having a structure having at least either a triazine structure or a biuret structure in the molecule and terminated with a uretdione group. SOLUTION: There is provided a curing agent having a structure having at least either a triazine structure composed of an aliphatic and/or alicyclic diisocyanate and represented by formula I (wherein R is a residue derived by removing an isocyanate group from the aliphatic or alicyclic diisocyanate) or a biuret structure represented by formula II (wherein R is as defined in formula I) in the molecule and terminated with a uretdione group represented by formula III (wherein X is -R1 -NH-CO-R2 or R3 ; R1 is the same as R in formula I; R2 is a residue derived by removing hydrogen from an active hydrogen compound such as a monool or a monoamine; R3 is a residue derived by removing an isocyanate group from a monoisocyanate). It is suitable that the curing agent has a weight-average molecular weight of 700-5,000, a viscosity of 1,000-100,000 mPa.s/25 deg.C and an available isocyanate group content of 5-20%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a curing agent which does not contain a volatile blocking agent, and a one-component coating composition using the curing agent.

[0002]

2. Description of the Related Art At present, in a one-component polyurethane coating material represented by a paint, a blocked isocyanate in which an active isocyanate group is blocked by an oxime compound or a lactam compound is used as a curing agent. However, because of the release of the blocking agent at the time of baking, the environment is deteriorated due to the generation of white smoke and odor, the baking coating furnace is contaminated by the generation of tarnish, and the necessity of maintenance is required. There is a problem of surface roughening and yellowing.

In order to solve this disadvantage, Japanese Patent Publication No. Sho 57-4
JP-A-6447, JP-B-64-5627, JP-B-2-16332 and the like disclose a curing agent containing no uretdione group in the structure without using a blocking agent.
This means that the uretdione group formed by two moles of NCO groups can be dissociated into two moles of NCO groups again by heating and react with the polyol, so that it can be used as a curing agent. Therefore,
There is no volatilization of the blocking agent, and the above-mentioned problem with the blocking agent can be solved. However, these hardeners are hardeners for powder coatings and are difficult to use in solvent-based coatings due to their solid state.

In Japanese Patent Application Laid-Open No. HEI 8-120222, a uretdione group is introduced for the purpose of reducing the amount of a blocking agent. However, its use is limited to electrodeposition paints, and it is used together with a volatile blocking agent. However, the above-mentioned problem caused by the blocking agent has not been completely solved. Therefore, the fields where one-component polyurethane coating materials are used, for example, pre-coated metals such as top coat paints for automobiles, chipping-resistant paints, electrodeposition paints, automobile parts, metal products such as home appliances and office equipment, rust prevention For a steel plate, a plastic paint, an adhesive, an adhesion-imparting agent, a sealing agent, and the like, a one-component polyurethane coating material that does not volatilize a blocking agent has been desired.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a curing agent which does not contain a volatile blocking agent, and a one-part coating composition using the curing agent.

[0006]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that the above object can be achieved by making the isocyanate group of the polyisocyanate a uretdione group, and have completed the present invention. That is, the present invention is as follows.

1) A triazine structure represented by the general formula (1) and / or a biuret structure represented by the general formula (2) composed of an aliphatic and / or alicyclic diisocyanate in one molecule. A curing agent having at least one and having a structure containing a uretdione group whose terminal is represented by the general formula (3).

[0008]

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(In the formula, R represents a residue other than the isocyanate group of the aliphatic or alicyclic diisocyanate.)

[0010]

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(In the formula, R represents a residue other than the isocyanate group of the aliphatic or alicyclic diisocyanate.)

[0012]

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(Wherein X is -R ₁ -NH-CO-R ₂ ,
Or an -R _3. However, R ₁ is a residue other than an isocyanate group of an aliphatic or alicyclic diisocyanate;
₂ represents a residue other than hydrogen of an active hydrogen compound such as a monool or a monoamine, and R ₃ represents a residue other than an isocyanate group of a monoisocyanate. 2) A curing agent represented by the general formula (4) having a structure containing a uretdione group composed of an aliphatic and / or alicyclic diisocyanate.

[0014]

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(Wherein X is -R ₁ -NH-CO-R ₂ ,
Or an -R _3. However, R ₁ is a residue other than an isocyanate group of an aliphatic or alicyclic diisocyanate;
₂ represents a residue other than hydrogen of an active hydrogen compound such as a monool or a monoamine, and R ₃ represents a residue other than an isocyanate group of a monoisocyanate. R ₄ represents a residue other than hydrogen of the polyol, and n ≧ 2. 3) A one-part coating composition comprising the curing agent according to the above 1 and / or the curing agent according to the above 2 and a polyol having a resin hydroxyl value of 20 to 300 mgKOH / g as main components.

Hereinafter, the present invention will be described in more detail. Examples of the aliphatic and / or alicyclic diisocyanate used in the present invention include tetramethylene diisocyanate, pentane diisocyanate, hexamethylene diisocyanate (hereinafter abbreviated as HDI), 2,2,4 (or 2,4,4). ) -Trimethyl-1,6-diisocyanatohexane, lysine diisocyanate, isophorone diisocyanate (hereinafter abbreviated as IPDI), 1,3-bis (isocyanatomethyl) -cyclohexane, 4,4-dicyclohexylmethane diisocyanate, norbornene diisocyanate, etc. Is raised. These may be used alone or in combination.

The compound having a triazine structure composed of the aliphatic and / or alicyclic diisocyanate is preferably a polyisocyanate containing as a main component a trimer of the diisocyanate having a triazine structure of the general formula (1). Nurate is mentioned. In the present invention, a polyisocyanurate partially modified with a monoalcohol, a diol, or the like may be used. Examples of the compound having a biuret structure composed of the aliphatic and / or alicyclic diisocyanate include the above-mentioned general formula (2), for example, a biuret-type polyisocyanate obtained by reacting the diisocyanate with water or the like. Is mentioned.

The curing agent of the present invention has at least one of the above triazine structure and / or biuret structure in one molecule, and has a terminal containing a uretdione group represented by the above general formula (3). doing. The weight average molecular weight is 7
00 to 5000, viscosity: 1000 to 10000
0 mPa · s / 25 ° C. is good. The effective isocyanate group content is preferably 5 to 20%. Here, the effective isocyanate group content (hereinafter, abbreviated as effective NCO%) is determined by preparing a calibration curve with an infrared spectrophotometer (FT-IR) to determine the uretdione group content, from which the uretdione group is dissociated. The content of isocyanate groups involved in the urethane cross-linking reaction that occurs when the curing is performed is a value expressed in terms of% by weight based on the curing agent. The blending amount with the polyol is calculated based on this.

The curing agent of the present invention is a curing agent represented by the general formula (4) having a structure containing a uretdione group composed of an aliphatic and / or alicyclic diisocyanate. The curing agent of the present invention may have the above triazine structure and biuret structure in the molecule. The weight average molecular weight is 500 to 5000, and the viscosity is 1
000 to 100,000 is good. Effective NCO% is 5-20
% Is good.

The crosslinking mechanism using the curing agent of the present invention is such that the above-mentioned terminal uretdione group is dissociated by heating, again producing 2 mol of isocyanate groups and reacting with the hydroxyl groups of the polyol. . Therefore, there is no volatilization of the blocking agent, and the above-mentioned problem with the blocking agent can be completely solved. The curing agent containing a triazine structure in the molecule of the present invention can be obtained, for example, by the following method. First, an aliphatic and / or alicyclic diisocyanate is reduced by -1 in the presence of a uretdionation catalyst.
The reaction is carried out at a reaction temperature of 0 ° C. to 120 ° C., and after adding a reaction terminator, unreacted diisocyanate is distilled off to obtain a uretdione group-containing polyisocyanate.
The obtained uretdione group-containing polyisocyanate is reacted at a reaction temperature of 40 to 120 ° C. in the presence of an isocyanuration catalyst, and after adding a reaction terminator, the terminal isocyanate group is converted to active hydrogen such as monoalcohol or monoamine. It is obtained by reacting with one compound.

As another method, first, an aliphatic and / or alicyclic diisocyanate is reacted at a reaction temperature of 40 ° C. to 120 ° C. in the presence of an isocyanurate catalyst, and a reaction terminator is added. The reaction is stopped and unreacted diisocyanate is distilled off to obtain a polyisocyanate having a triazine structure. The obtained polyisocyanate is reacted with monoisocyanate at a reaction temperature of -10C to 120C in the presence of a uretdionation catalyst,
After terminating the reaction with a reaction terminator, it can also be obtained by distilling off diisomer of monoisocyanate and monoisocyanate which is a by-product.

The curing agent having a biuret structure of the present invention can be obtained, for example, as follows. Water is added to the uretdione group-containing polyisocyanate obtained by the above-described method, and biuret is formed at a reaction temperature of 100 ° C to 160 ° C, and the terminal isocyanate group is a monoalcohol,
It is obtained by reacting with a compound having one active hydrogen such as monoamine.

As another method, water or the like is added to an aliphatic and / or alicyclic diisocyanate,
Biuret at a reaction temperature of 60 ° C., and reacting the obtained polyisocyanate having a biuret structure with monoisocyanate at −10 ° C. to 120 ° C. in the presence of a uretdione catalyst to form monoisocyanate and monoisocyanate as a by-product It can also be obtained by distilling off the dimer.

As the uretdionation catalyst used here, a catalyst having a high selectivity for the uretdion group is preferable. For example, trisdimethylaminophosphine, trisdiethylaminophosphine, trisdipropylaminophosphine, trisdibutylaminophosphine, trisdipentylaminophosphine, trisdialkylaminophosphine such as trisdihexylaminophosphine, and tetramethylbiphosphine, tetraethylbiphosphine,
Tetraalkylbiphosphines, such as tetrapropylbiphosphine, tetrabutylbiphosphine, tetrapentylbiphosphine, tetrahexylbiphosphine, and tetraphenylbiphosphine, and 1,2-bis (dialkylphosphine) alkylene, 1,2-bis ( Phenylphosphine) alkylene, 1,2-bis (dialkylphosphine) phenylene, 1,2-bis (diphenylphosphine) phenylene and the like.

Here, examples of the alkyl group include methyl, ethyl, propyl, butyl, pentyl, hexyl, and examples of the alkylene group include methylene, ethylene, propylene, and butylene. The catalyst can be used in an amount of 0.01 to 5% by weight based on the diisocyanate or polyisocyanate used.

Examples of the reaction terminator for the uretdionation reaction include the following. Examples thereof include an alkylating agent, an acylating agent, sulfur, or atmospheric oxygen or a compound that releases oxygen, sulfuric acid, a sulfate, a phosphoric acid, a phosphate, and the like. These may be used alone or in combination. The addition amount of the reaction terminator can be in the range of 1.0 to 10 times the molar amount of the catalyst.

The uretdionation is usually carried out at -10 ° C to 120 ° C.
At the reaction temperature of When the reaction temperature is lower than −10 ° C., a long reaction time is required, which may be disadvantageous in production. When the temperature exceeds 120 ° C., the obtained curing agent tends to be colored. Examples of the isocyanuration catalyst include hydrides of tetraalkylammonium such as tetramethylammonium, tetraethylammonium, and tetrabutylammonium, and organic weak acid salts, or trimethylhydroxypropylammonium, trimetlhydroxyethylammonium, and triethylhydroxyl. Hydroxyalkyl ammonium hydroxide and organic weak acid salts such as propyl ammonium and triethyl hydroxyethyl ammonium, or
Examples thereof include alkali metal salts of alkyl carboxylic acids such as acetic acid, caproic acid, octylic acid, and myristic acid; metal salts of the above carboxylic acids such as tin, zinc, and lead; and compounds containing an aminisilyl group such as hexamethyldisilazane. The catalyst is added in an amount of 0.01 to 5% by weight based on the diisocyanate or polyisocyanate used.
It can be used in the range of weight%.

The reaction terminator for the isocyanuration reaction is as follows:
The same uretdionization reaction terminator can be used. The addition amount of the reaction terminator is 1.
It can be added in the range of 0 to 10 moles.
The isocyanuration reaction is usually performed at a reaction temperature of 40 ° C to 120 ° C. If the temperature is lower than 40 ° C., the reaction rate is low and productivity is disadvantageous. If the temperature exceeds 120 ° C., the obtained curing agent tends to yellow.

Examples of the compound having one active hydrogen used for blocking the terminal isocyanate group include aliphatic, alicyclic, aromatic monools, monoamines, lactams, oximes, pyrazoles, and imidazoles. Compounds, such as methanol, ethanol, propanol, butanol, amyl alcohol, pentanol, hexanol, heptanol, nonyl alcohol, cyclobutanol, cyclohexanol, phenol, benzyl alcohol, aminopropane, aminobutane, aminopentane, aminohexane , Aminooctane, ε-caprolactam, δ-valerolactam, methyl ethyl ketoxime, cyclohexanonoxime, pyrazole, 3,5-dimethylpyrazole, imidazole,
3-Methylimidazole and the like. The above compounds can be selected in accordance with various conditions such as a use to be used, a solvent, various additives, coating conditions, baking conditions, and required physical properties of a coating film.

Examples of the monoisocyanate compound include methyl isocyanate, ethyl isocyanate,
Isopropyl isocyanate, butyl isocyanate,
Examples include phenyl isocyanate, α-naphthyl isocyanate, β-naphthyl isocyanate nitrophenyl isocyanate, and vinyl isocyanate. The curing agent represented by the general formula (4) having a structure containing a uretdione group composed of an aliphatic and / or alicyclic diisocyanate of the present invention can be obtained, for example, as follows.

The uretdione group-containing polyisocyanate obtained by the above-described method is mixed with a polyol at 60 ° C. to 160 ° C.
The reaction is carried out at a reaction temperature of ° C. to obtain a urethane-type polyisocyanate. It can be obtained by reacting a terminal isocyanate group with an active hydrogen compound such as a monoalcohol or a monoamine. As another method, an aliphatic and / or alicyclic diisocyanate is added to a polyol at 60 ° C.
The reaction is carried out at a reaction temperature of ~ 160 ° C to obtain a urethane-type polyisocyanate. Next, monoisocyanate is added, reacted at a reaction temperature of -10 ° C to 120 ° C in the presence of a uretdionation catalyst, and after adding a reaction terminator, monoisocyanate and a dimer of monoisocyanate as a by-product are added. It can be obtained by distillation.

As the polyol used here, those having an average number of functional groups exceeding 2 are preferable. Specific examples include polyether polyols and polyester polyols. Particularly preferred are trihydric alcohols such as trimethylolpropane and glycerin, polycaprolactone polyol, polytetramethylene glycol, polypropylene glycol and the like.

As the polycaprolactone polyol,
Praxel 305, Praxel 308, Praxel 31
2AL etc. (all manufactured by Daicel Chemical Industries, Ltd.), and polytetramethylene glycol is PTG100
And PTG2000 (both manufactured by Hodogaya Chemical Co., Ltd.), and examples of polypropylene glycol include Exenol 820 and Exenol 840 (both manufactured by Asahi Glass Industry Co., Ltd.). The reaction temperature between these polyols and the above-mentioned diisocyanate is from 40 ° C to 160 ° C. Preferably it is 80 to 140 degreeC.

The curing agent of the present invention can contain a suitable solvent as needed. Examples of the solvent include hydrocarbons such as xylene, toluene, cyclohexane, mineral spirit and naphtha, ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone, and esters such as ethyl acetate, n-butyl acetate and cellosolve acetate. .

The one-part coating composition of the present invention is formed with a polyol and the curing agent as main components. Examples of the polyol in the present invention include aliphatic hydrocarbon polyols, polyether polyols, polyester polyols, epoxy resins, fluorinated polyols, and acrylic polyols.

Specific examples of the hydrocarbon polyols include:
For example, terminal hydroxylated polybutadiene and hydrogenated products thereof can be mentioned. As the polyether polyols, for example, polyether polyols obtained by adding a single or mixture of alkylene oxides such as ethylene oxide and propylene oxide to a single or mixture of polyhydric alcohols such as glycerin and propylene glycol, Polytetramethylene glycols, polyether polyols obtained by reacting polyalkylene oxides with polyfunctional compounds such as ethylenediamine and ethanolamines, and so-called polymer polyols obtained by polymerizing acrylamide and the like using these polyethers as a medium Kinds are included.

Examples of the polyester polyols include succinic acid, adipic acid, sebacic acid, dimer acid,
Maleic anhydride, phthalic anhydride, isophthalic acid, terephthalic acid, and other dicarboxylic acids selected from the group of carboxylic acids alone or in combination with ethylene glycol, propylene glycol, diethylene glycol, neopentyl glycol, 1,4-butane Diols, 1,6-hexanediol, trimethylolpropane, polyester polyol resins obtained by a condensation reaction with a polyhydric alcohol alone or a mixture selected from the group of glycerin,
And, for example, polycaprolactones obtained by ring-opening polymerization of ε-caprolactone using a polyhydric alcohol, and the like.

Examples of epoxy resins include novolak type, β-methyl epichloro type, cyclic oxirane type, glycidyl ether type, glycol ether type, epoxy type of aliphatic unsaturated compound, epoxidized fatty acid ester type, and polyvalent carboxylic acid. Ester type, aminoglycidyl type,
Examples thereof include epoxy resins of halogenated type and resorcinol type, and resins obtained by modifying these epoxy resins with an amino compound, a polyamide compound and the like.

As the fluorinated polyols, for example,
JP-A-57-34107, JP-A-61-2753
And copolymers of a fluoroolefin and cyclohexyl vinyl ether, hydroxyalkyl vinyl ether, monocarboxylic acid vinyl ester, and the like, which are disclosed in Japanese Patent Publication No. 11-2011 and the like. Acrylic polyols can be obtained by copolymerizing a polymerizable monomer having one or more active hydrogens in one molecule with another monomer copolymerizable therewith. For example, acrylates having active hydrogen such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxybutyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxymethacrylate Propyl, methacrylic acid-
Methacrylic acid esters having active hydrogen such as 2-hydroxybutyl, or polyvalent active hydrogen such as acrylic acid monoester or methacrylic acid monoester of glycerin, trimethylolpropane acrylic acid monoester or methacrylic acid monoester ( (Meth) acrylic acid esters alone or in a mixture selected from the group consisting of methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, and acrylic acid
Acrylic esters such as 2-ethylhexyl, methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-hexyl methacrylate, cyclohexyl methacrylate, lauryl methacrylate, methacrylic acid Methacrylic esters such as glycidyl, and, if necessary, acrylic acid, methacrylic acid, maleic acid, unsaturated carboxylic acids such as itaconic acid, acrylamide, N-methylolacrylamide, unsaturated amides such as diacetonaacrylamide, and Styrene, vinyltoluene, vinyl acetate, acrylonitrile, and other polymerizable monomers.

Further, polymerizable ultraviolet-stable monomers exemplified in JP-A-1-261409 and JP-A-3-6273, for example, 4- (meth) acryloyloxy-2,2,6 , 6-tetramethylpiperidine, 4-
(Meth) acryloylamino-2,2,6,6-tetramethylpiperidine, 1-crotonoyl-4-crotonoyloxy-2,2,6,6-tetramethylpiperidine,
Acrylic polyol resins obtained by copolymerizing 2-hydroxy-4- (3-methacryloxy-2-hydroxypropoxy) benzophenone and the like can also be used.

The polyol in the one-pack coating composition of the present invention has a resin hydroxyl value of 20 to 300 mgK.
OH / g. Resin hydroxyl value is 20mgKOH / g
If it is less than 3, the crosslinking density of urethane due to the reaction with the isocyanate component decreases, and the function of urethane bond cannot be exhibited. If the resin hydroxyl value exceeds 300 mgKOH / g, the crosslinking density increases, The mechanical properties of the coating film decrease, and in some cases, the hydroxyl groups and the isocyanate groups do not completely react, which is not preferable.

The one-part coating composition of the present invention can further improve the curability by using a catalyst that dissociates the uretdione group at a low temperature.
Specifically, for example, organic tin compounds such as dibutyltin acetate, dibutyltin oxide, and dimethyltin oxide, triethylenediamine, triethylamine, N, N, N ′, N′-tetrakis (2-hydroxypropyl) ethylenediamine, N -Methylmorpholine, 1,2-dimethylimidazole, 1,5-diazabicyclo (4,3,0) nonene-5,1,8-diazabicyclo (5,4,0) -undecene-7 (hereinafter abbreviated as DBU) Amine compounds such as borane salts, DBU phenol salts, DBU octyl salts, DBU carbonates and other amine salt catalysts, alkoxides such as sodium methylate, aluminum, chromium cobalt, iron, and the like. Of trivalent or tetravalent metals such as tin, lead, titanium, and molybdenum Cetyl acetone salts, oxalyl chlorides, oxalic acid esters such as oxalic acid diphenyl ester, metal salts of tetraphenylboron such as sodium tetraphenylboron and potassium tetraphenylboron, and the third of tetraphenylboron such as triethylamine tetraphenylboron Secondary amine salts, dioxane,
And trisubstituted phosphites such as trimethyl phosphite, tributyl phosphite, and triphenyl phosphite.

After the uretdione group is dissociated using the uretdione group dissociation catalyst, a catalyst for accelerating the urethanization reaction can be added. Examples of the urethane-promoting catalyst include organic tin-based, organic zinc-based, and organic zirconium-based catalysts. In particular, organotins are good. Examples of the organotin-based compounds include butyltin maleate, butyltin laurate, dibutyltin maleate, dibutyltin reureate, dibutyltin acetate, dibutyltin oxide, and dimethyltin oxide.

The one-part coating composition of the present invention includes:
Coloring during heating can be reduced by adding an antioxidant, a heat stabilizer, a metal deactivator, and the like. Examples of the additive include a diacyl hydrazine compound group, a benzotriazole compound group, an aminotriazole compound group, a polycarboxylic acid compound group, a compound group containing a hydrazide group or a semicarbazide group, a phosphite compound group, and a divalent compound. A compound selected from the group of tin compounds can be used.

Specifically, examples of the diacylhydrazine-based compound include N, N'-diformylhydrazine,
N, N'-diacetylhydrazine, N, N'-dipropionylhydrazine, N, N'-butyrylhydrazine, N
-Formyl-N'-acetylhydrazine, N, N'-dibenzoylhydrazine, N, N'-ditoluoylhydrazine, N, N'-disalicyloylhydrazine, N-formyl-N'-salicyloylhydrazine , N-formyl-
N'-butyl-substituted salicyloylhydrazine, N-acetyl-N'-salicyloylhydrazine, N, N'-bis (3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyl) hydrazine Oxalic acid-di-
(N'-salicyloyl) hydrazine, adipic acid-di-
(N′-salicyloyl) hydrazine, dodecaneoyl-di- (N′-salicyloyl) hydrazine and the like.

Examples of the benzotriazole compound include 1H-benzotriazole and derivatives thereof. As derivatives of 1H-benzotriazole,
For example, tolyltriazole, xylyltriazole,
4- (or 5-) ethylbenzotriazole, 4-
(Or 5-) carboxylbenzotriazole, 4-
(Or 5-) benzotriazole butyl ester, 4
-(Or 5-) benzotriazole methyl ester,
4- (or 5-) chlorobenzotriazole or the like, a derivative in which hydrogen of a benzene ring is substituted with an alkyl group, a substituted alkyl group, a carboxyl group, an alkyl ester group, a halogen group, 1-hydroxymethylbenzotriazole,
(2,3-dihydroxypropyl) benzotriazole, 1- (1,2-dicarboxyethyl) benzotriazole, 1- (N, N-bis (2-ethylhexyl) aminomethyl) benzotriazole, 1-chlorobenzotriazole, Derivatives in which hydrogen bonded to nitrogen at position 1 is substituted with an alkyl group, substituted alkyl group, halogen, alkali metal, such as sodium salt of benzotriazole and potassium salt of benzotriazole, hydrogen of benzene ring and nitrogen at position 1, such as potassium tolyltriazole salt And a derivative in which hydrogen bonded to is substituted with an alkyl group, a substituted alkyl group, a carboxyl group, an alkyl ester group, halogen, an alkali metal, or the like.

Examples of the aminotriazole compounds include 3-amino-1,2,4 triazole, 3-amino-1,2,4-triazole-5 carboxylic acid, and 3-amino-5 methyl-1,2. , 4-triazole, 3-methyl-5-heptyl-1,2,4-triazole and the like, and hydrogen of an amino group of the above compound is, for example, a formyl group, an acetyl group, a propionyl group, a benzoyl group, a toluoyl group, a salicyloyl group, etc. Compounds substituted with an acyl group, for example, 3- (N-salicyloyl) amino-1,
2,4 triazole, 3- (N-salicyloyl) amino-5methyl-1,2,4 triazole, 3- (N-acetyl) amino-1,2,4 triazole-5 carboxylic acid and the like can be mentioned. .

Examples of the polycarboxylic acid compounds include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, spearic acid, azelaic acid, sebacic acid, malic acid, tartaric acid, cyclopropanedicarboxylic acid and the like. Aliphatic unsaturated dicarboxylic acids such as maleic acid, fumaric acid, citraconic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, carboxyphenylacetic acid, carboxyphenylpropionic acid, phenylenediacetic acid, etc. Examples thereof include tricarboxylic or higher polycarboxylic acids such as aromatic dicarboxylic acid tricarballylic acid and trimellitic acid.

The compound containing a hydrazide group is, for example, a compound obtained by a reaction of carboxylic acid chloride with hydrazine or substituted hydrazine, or a transesterification reaction of a carboxylic acid ester with hydrazine or substituted hydrazine. Hydrazide, lauric hydrazide, salicylic hydrazide, propionic acid-N, N-dimethylhydrazide, 2-ethylhexanoic acid-N-propylhydrazide, adipic dihydrazide, sebacic dihydrazide, dodecane dihydrazide, isophthalic dihydrazide, sebacic acid-bis-
(N, N-dimethylhydrazide) and the like.

Compounds containing a semicarbazide group include:
For example, it can be obtained by a reaction between an isocyanate compound and an N, N-disubstituted hydrazine. Examples of the N, N-disubstituted hydrazine include N, N-dimethylhydrazine, N, N-diethylhydrazine, N, N-dipropylhydrazine, N, N-diisopropylhydrazine, N, N-diisopropylhydrazine,
N-distearyl hydrazine, N-methyl-N-ethylhydrazine, N-methyl-N-isopropylhydrazine, N-methyl-N-benzylhydrazine, N, N-di (β-hydroxyethyl) -hydrazine and the like can be mentioned. . These N, N-disubstituted hydrazines may be used alone or in combination of two or more.

As the isocyanate compound, for example,
Tetramethylene diisocyanate, pentamethylene diisocyanate, HDI, 2,2,4 (or 2,4
4) -trimethyl-1,6-diisocyanatohexane,
Aliphatic or alicyclic diisocyanates such as lysine diisoanate, 1,3-bis (isocyanatomethyl) -cyclohexane, 4,4-dicyclohexylmethane diisocyanate, xylylene diisocyanate, tetramethyl xylene diisocyanate, 4,4-diphenylmethane diisocyanate; 1,4-phenylene diisocyanate, 2,4-tolylene diisocyanate, aromatic diisocyanates such as naphthalene diisocyanate, and polyisocyanates derived from these diisocyanates, n-butyl isocyanate, n-hexyl isocyanate, n-octyl isocyanate, Monoisocyanates such as phenyl isocyanate can be mentioned.

Examples of polyisocyanates derived from diisocyanates include isocyanurate-type polyisocyanates, burette-type polyisocyanates, and urethane-type polyisocyanates. Examples of the phosphite compound include dialkyl phosphites such as dilauryl hydrogen phosphite, diallyl phosphites such as diphenyl hydrogen phosphite, triethyl phosphite, tributyl phosphite, and tris (2-ethylhexyl). ) Triphosphite such as phosphite, tridodecyl phosphite, tris (tridecyl) phosphite, tristearyl phosphite, distearyl pentaerythritol diphosphite, trilauryl trithiophosphite, bis (dodecyl) pentaerythritol diphosphite Alkyl esters,
Triphenyl phosphite, tris (nonylphenyl)
Triallyl esters such as phosphite, diphenylmono (2-ethylhexyl) phosphite, diphenylmonodecylphosphite, diphenylmono (tridecyl) phosphite, tetraphenyltetra (tridecyl) pentaerythritol tetraphosphite, tetra (tridecyl) 4, Examples include trialkylallyl phosphites such as 4-isopropylidene diphenyl phosphite, bis (nonylphenyl) pentaerythritol diphosphite, and tris (2,4-di-t-butylphenyl) phosphite. These can be used alone or in combination of two or more.

The divalent tin compound may be an organic compound or an inorganic compound. Examples of the divalent organic tin compound include stannous carboxylate, stannous sulfonate, stannous alkyl compounds, stannous alkyl ether compounds, and the like. Examples of stannous carboxylate compounds include stannous formate, stannous acetate, stannous propionate, stannous butyrate, stannous hexanoate, stannous 2,2-methylbutane, and stannous heptanoate. Stannous, stannous ethylhexanoate, stannous octoate, stannous nonanoate, stannous decanoate, stannous undecanoate,
Stannous dodecanoate, stannous tetradecanoate, stannous hexadecanoate, stannous heptadecanoate, stannous octadecanoate, stannous eicosanoate, stannous docosanoate, stannous hexacosanoate, triacontan Stannous acid, stannous acrylate, stannous methacrylate, stannous oxalate, stannous malonate, stannous succinate, stannous glutarate, stannous adipate, stannous maleate Istin etc.

The stannous sulfonate compound includes, for example, stannous sulfamate. Examples of the alkyl stannous compound include diethyl tin, di-n-propyl tin, diisopropyl tin, di-n-butyl tin, diisobutyl tin and the like. Examples of the stannous alkyl ether compound include dimethoxytin, diethoxytin, di-n-propoxytin, diisopropoxytin, di-n-butoxytin, and diisobutoxytin.

Examples of the divalent inorganic tin compound include stannous chloride, stannous bromide, stannous iodide, stannous hydroxide,
There are stannous sulfide, stannous phosphate, tin dihydrogen phosphate, stannous sulfate, stannous oxide and the like. These divalent tin compounds can be used alone or in combination of two or more. In the one-pack coating composition of the present invention, other components used in the technical field in addition to the components described above may be blended and used depending on the purpose. As these other components, for example, organic pigments, inorganic pigments, metal powder, pigment dispersant, foam inhibitor,
Anti-settling agents, leveling agents, thixotropic agents, light stabilizers, and other additives.

The curing agent and the one-component coating composition of the present invention can be used in a field where a one-component polyurethane coating material is used, for example, a top coating for automobiles, a chipping-resistant coating, an electrodeposition coating, an automobile part, It can be used as pre-coated metal for metal products such as home appliances and office equipment, rust-proof steel plates, plastic paints, adhesives, adhesives, sealants and the like.

[0057]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described more specifically with reference to examples and the like, but the present invention is not limited to these examples and the like. In addition, "part" represents a weight part. The physical properties in the examples were measured by the following methods. Effective isocyanate group content (hereinafter abbreviated as effective NCO%)
Was obtained by preparing a calibration curve with an infrared spectrophotometer (FT-IR), obtaining the uretdione group content, and calculating from it.

For the measurement of volatile components, the coating composition was dried at 80 ° C. for 1 hour, then applied to a dry film thickness of 50 μm, and dried under reduced pressure at room temperature for 24 hours. Then 160
It was determined from the weight loss rate after heating at 1 ° C. for 1 hour. The gel fraction was determined by adding 1% of dibutyltin dilaurate to the coating solution based on the solid content of the coating solution, spray-coating the coating solution, immersing the coating film baked at a predetermined baking temperature in acetone, and heating at 20 ° C. for 24 hours.
It was determined from the weight of the coating film taken out and dried after the time treatment.

[0059]

[Synthesis Example 1] [Synthesis of uretdione group-containing polyisocyanate component] In a four-necked flask equipped with a stirrer, a thermometer, and a condenser, 500 parts of HDI and 5 parts of tris-diethylaminophosphine were charged and reacted at 60 ° C for 4 hours. Then, 4 parts of phosphoric acid as a reaction terminator is added. After heating at 80 ° C. for 1 hour, cooling, filtering, and using a falling thin film distillation apparatus, the first time was 155 ° C., 0.3 torr, and the second time was 145 ° C.
Unreacted HDI is removed at 0.2 torr at 0.2 ° C.

The resulting uretdione group-containing polyisocyanate had an isocyanate group content of 24%. This uretdione group-containing polyisocyanate compound is referred to as polyisocyanate A.

[0061]

[Synthesis Example 2] [Synthesis of uretdione group-containing polyisocyanate component] In a four-necked flask equipped with a stirrer, a thermometer, and a condenser, 500 parts of IPDI and 5 parts of tris-diethylaminophosphine were charged and reacted at 60 ° C for 4 hours. ,
Four parts of phosphoric acid, a reaction terminator, is added. After heating at 80 ° C. for 1 hour, cooling, filtering, and using a falling film thin-film distillation apparatus, the first time was 155 ° C., 0.3 torr, and the second time was 14 hours.
Unreacted IPDI is removed at 5 ° C. and 0.2 torr.

The resulting uretdione group-containing polyisocyanate had an isocyanate group content of 18%. This uretdione group-containing polyisocyanate compound is referred to as polyisocyanate B.

[0063]

[Synthesis Example 3] [Synthesis of polyisocyanate component] HD was placed in a four-necked flask equipped with a stirrer, thermometer, and cooling tube.
I, 500 parts, and polycaprolactone polyol Plaxel 308 (trade name, manufactured by Daicel Chemical Industries, Ltd.) 1
70 parts were charged and reacted at 100 ° C. for 1 hour. The obtained reaction solution was subjected to 160 ° C.
Unreacted HDI is distilled off at 0.2 torr.

The obtained polyisocyanate had an isocyanate group content of 9.4%. This uretdione group-containing polyisocyanate compound is converted to polyisocyanate C
And

[0065]

Example 1 A four-necked flask equipped with a stirrer, a thermometer, and a condenser was charged with 500 parts of polyisocyanate A and 160 parts of xylene, and stirred at 60 ° C., and 2.0 parts of tetramethylammonium capriate was added as a catalyst. It was added in portions every 30 minutes. The reaction was continued at 60 ° C., and after 4 hours, 1.3 parts of phosphoric acid was added to stop the reaction.
For 1 hour. 140 parts of 1-butanol was added to the obtained polyisocyanate under stirring at 80 ° C. to completely react with the isocyanate group.

The obtained curing agent had a weight average molecular weight of 220
0, viscosity 4000 mPa · s / 25 ° C., effective NCO% was 9.9%. Was subjected to structural confirm infrared spectrophotometer (FT-IR), uretdione groups 1767cm ^-1, confirming the peak of the triazine ring to 1688 cm ^-1.

[0067]

Example 2 In a four-necked flask equipped with a stirrer, a thermometer and a condenser, isocyanurate-type polyisocyanate T was placed.
500 parts of PA-100 (trade name, manufactured by Asahi Kasei Corporation)
821 parts of butyl isocyanate were charged, and 1.5 parts of trisdimethylaminophosphine was added under stirring at 60 ° C. The reaction uretdione group formation rate at 60 ° C. for 6 hours was measured with an infrared spectrophotometer. When the rate reached 50%, 1.5 parts of phosphoric acid was added to stop the reaction. After filtering the obtained compound, using a falling-film thin-film distillation apparatus, the first time 120 ° C.,
At 1 torr and a second time at 130 ° C. and 0.2 torr, butyl isocyanate as a by-product and a dimer of butyl isocyanate were distilled off.

The weight average molecular weight of the obtained curing agent was 95.
0, viscosity 2500 mPa · s / 25 ° C., effective NCO% was 15.0%. Was subjected to structural confirm infrared spectrophotometer (FT-IR), uretdione groups 1767cm ^-1, confirming the peak of the triazine ring to 1688 cm ^-1.

[0069]

Example 3 In a four-necked flask equipped with a stirrer, a thermometer and a condenser, isocyanurate-type polyisocyanate T was placed.
-1890 L (manufactured by Huls Co., Ltd .; 500 parts) and 435 parts of isosobutyl isocyanate were charged, and 1.5 parts of trisdimethylaminophosphine was added under stirring at 60 ° C. The reaction uretdione group formation rate at 60 ° C. for 6 hours was measured with an infrared spectrophotometer. When the rate reached 50%, 1.5 parts of phosphoric acid was added to stop the reaction. After filtering the obtained compound, using a falling-film thin-film distillation apparatus, the first time 120 ° C.,
At 1 Torr and a second time at 130 ° C. and 0.2 Torr, isobutyl isocyanate as a by-product and a dimer of isobutyl isocyanate were distilled off.

The weight average molecular weight of the obtained curing agent was 150.
0, viscosity 20000 mPa · s / 25 ° C, effective NCO%
Was 12.5%. Infrared spectrophotometer (FT-IR)
As a result, a uretdione group was found at 1767 cm ^-1 and a peak of a triazine ring was found at 1688 cm ^-1 .

[0071]

EXAMPLE 4 A biuret-type polyisocyanate 24A- was placed in a four-necked flask equipped with a stirrer, thermometer, and cooling tube.
100 parts (trade name, manufactured by Asahi Kasei Corporation) and 857 parts of butyl isocyanate were added, and 1.5 parts of trisdimethylaminophosphine was added under stirring at 60 ° C. 60
The reaction uretdione group formation rate was measured at 6 ° C. for 6 hours with an infrared spectrophotometer, and when it reached 50%, 1.5 parts of phosphoric acid was added to stop the reaction. After filtering the obtained compound, the first time at 120 ° C., 1 torr using a falling film thin-film distillation apparatus.
r, the second time butyl isocyanate and a dimer of butyl isocyanate were distilled off at 130 ° C. and 0.2 torr.

The obtained curing agent has an average molecular weight of 800, a viscosity of 8000 mPa · s / 25 ° C., and an effective NCO% of 15.
2%. Was subjected to structural confirmed by infrared spectrophotometer (FT-IR), uretdione groups to 1767cm ^-1, confirmed the peak of biuret to 1690cm ^-1.

[0073]

Example 5 A four-necked flask equipped with a stirrer, a thermometer and a condenser was charged with 500 parts of polyisocyanate C and 330 parts of butyl isocyanate, and 1.5 parts of trisdimethylaminophosphine was added under stirring at 60 ° C. 60 ° C
The reaction uretdione group formation rate was measured with an infrared spectrophotometer for 6 hours, and when it reached 50%, 1.5 parts of phosphoric acid was added to stop the reaction. After filtering the obtained compound, the first time at 120 ° C., 1 torr using a falling film thin-film distillation apparatus.
At the second time at 130 ° C. and 0.2 torr, butyl isocyanate as a by-product and a dimer of butyl isocyanate were distilled off.

The weight average molecular weight of the obtained curing agent was 250.
0, viscosity 30000mPa · s / 25 ° C, effective NCO%
Was 7.7%. The structure was confirmed using an infrared spectrophotometer (FT-IR). As a result, a uretdione group was found at 1767 cm ⁻¹ and a peak of urethane bond was found at 1706 cm ⁻¹ .

[0075]

Example 6 A four-necked flask equipped with a stirrer, a thermometer and a condenser was charged with 500 parts of polyisocyanate B and trimethylolpropane, and reacted at 100 ° C. for 1 hour with stirring. Unreacted polyisocyanate B was distilled off from the obtained compound at 160 ° C. and 0.2 torr using a falling film thin-film distillation apparatus. 140 parts of 1-butanol was added to the obtained polyisocyanate under stirring at 80 ° C. to completely react with the isocyanate group.

The weight average molecular weight of the obtained curing agent is 200
0, viscosity 50000mPa · s / 25 ° C, effective NCO%
Was 9.0%. The structure was confirmed using an infrared spectrophotometer (FT-IR). As a result, a uretdione group was found at 1767 cm ⁻¹ and a peak of urethane bond was found at 1706 cm ⁻¹ .

[0077]

Example 7 The curing agent obtained in Example 2 and acrylic polyol (resin hydroxyl value of resin 100 mg-KOH / g) were blended so that the equivalent ratio of isocyanate groups to hydroxyl groups became 1, and ethyl acetate / ethyl acetate was used as a thinner. A mixed solution of toluene / butyl acetate / xylene / propylene glycol monomethyl ether acetate = 30/30/20/15/5 (weight ratio) was added to adjust the solid content to 30%.

At 140 ° C., 15
Gel fraction when baked at 0 ° C., 160 ° C. for 30 minutes,
The volatile content was measured. As a result, the gel fraction was 140 ° C.:8
0%, 150 ° C .: 92%, 160 ° C .: 97%, volatile content was 0.3%.

[0079]

Example 8 The same operation as in Example 7 was performed except that the curing agent obtained in Example 5 and a polyester polyol (hydroxyl value 220 mg-KOH / g) were used. The results obtained are as follows: gel fraction: 140 ° C .: 81%, 150 ° C .: 93
%, 160 ° C: 97%, volatile content was 0.2%.

[0080]

Comparative Example 1 The same operation as in Example 7 except that a blocked polyisocyanate (average molecular weight 900, viscosity 2000, effective NCO% 12.5%) obtained by blocking isocyanurate type polyisocyanate with methyl ethyl ketoxime as a curing agent was used. Was done. The results obtained were as follows: gel fraction 140 ° C: 90%, 150 ° C: 95%, 160 ° C:
97%, volatile content was 30%.

[0081]

According to the present invention, since the isocyanate group of the polyisocyanate is made to be a uretdione group so as not to have a blocking agent which volatilizes in the curing agent, the one-part coating composition using the same can be used for coating. There is no generation of white smoke, odor, tar, etc. due to volatilization of the blocking agent during baking, and there is no effect on the coating film by the remaining blocking agent.

Claims (3)

[Claims] 1. A triazine structure represented by the general formula (1) and / or a biuret structure represented by the general formula (2) composed of an aliphatic and / or alicyclic diisocyanate in one molecule. A curing agent having at least one and having a structure containing a uretdione group whose terminal is represented by the general formula (3). Embedded image (In the formula, R represents a residue other than the isocyanate group of the aliphatic or alicyclic diisocyanate.) (In the formula, R represents a residue other than the isocyanate group of the aliphatic or alicyclic diisocyanate.) (Wherein X is -R ₁ -NH-CO-R ₂ , or -R ₃
Represents However, R ₁ is a residue other than an isocyanate group of an aliphatic or alicyclic diisocyanate; R ₂ is a residue other than hydrogen of an active hydrogen compound such as a monool or a monoamine;
R ₃ represents a residue other than the isocyanate group of the monoisocyanate. ) 2. A curing agent represented by the general formula (4) having a structure containing a uretdione group composed of an aliphatic and / or alicyclic diisocyanate. Embedded image (Wherein X is -R ₁ -NH-CO-R ₂ , or -R ₃
Represents However, R ₁ is a residue other than an isocyanate group of an aliphatic or alicyclic diisocyanate; R ₂ is a residue other than hydrogen of an active hydrogen compound such as a monool or a monoamine;
R ₃ represents a residue other than the isocyanate group of the monoisocyanate. R ₄ represents a residue other than hydrogen of the polyol, and n ≧ 2. ) 3. The curing agent according to claim 1 and / or the curing agent according to claim 2, and a resin hydroxyl value of 20 to 300 mgK.
A one-part coating composition comprising an OH / g polyol as a main component.