JPH0841163A - Curative composition and one-component coating composition - Google Patents

Abstract

PURPOSE:To obtain a curative compsn. which does not yellow thermally, etc., and is suitable for a coating material for an automobile by using an aliph. or alicyclic blocked polyisocyanate and a specific diacylhydrazine compd. as the main components. CONSTITUTION:An aliph. or alicyclic blocked polyisocyanate is produced by reacting a polyisocyanate (e.g. of an isocyanurate type) which is derived from an aliph. diisocyanate (e.g. 1,6-hexamethylene diisocyanate) or an alicyclic diisocyanate (e.g. isophorone diisocyanate) with a blocking agent (e.g. nonylphenol). A curative compsn. is produced by using the blocked polyisocyanate and a diacylhydrazine compd. of formula I (wherein R<1> and R<2> are each H, alkyl, aryl, etc.) as the main components. A pref. example of the compd. of formula I is an N-salicyloyl-N'-acylhydrazine compd. of formula II (wherein R<3> is H, alkyl, etc.).

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel curing agent composition and a urethane thermosetting coating composition.

[0002]

2. Description of the Related Art Conventionally, polyurethane resin paints have very excellent abrasion resistance, chemical resistance and stain resistance, and their demand tends to increase. However, since polyurethane resin paints are generally two-part, it is extremely inconvenient to use them. That is, an ordinary polyurethane resin coating consists of two components, a polyol and a polyisocyanate, and it is necessary to store them separately and mix them at the time of coating. In addition, under the present circumstances, once mixed, the coating material gels in a short time and cannot be used. This makes it extremely difficult to perform automatic painting in the field of line painting such as automobiles or weak electric painting. In addition, since isocyanate reacts easily with water, it cannot be used in water-based paints such as electrodeposition paints. Further, since it is necessary to sufficiently wash the coating machine and the coating tank at the end of the work, the work efficiency is significantly reduced. In order to improve the above-mentioned drawbacks, it has been proposed to use a blocked isocyanate in which all active isocyanate groups are blocked with a blocking agent. This blocked isocyanate does not react with the polyol at room temperature, but at a high temperature, the blocking agent is dissociated and the active isocyanate group is regenerated to react with the polyol to cause a crosslinking reaction, so that the above-mentioned drawbacks can be improved.

However, although the coating film formed under the above-mentioned crosslinking temperature conditions uses an aliphatic or alicyclic non-yellowing polyisocyanate-based blocked isocyanate, some yellowing is inevitable. In paints that emphasize appearance, this slight yellowing is a factor that limits the uses of paints that use blocked isocyanates. Therefore, in the field of polyurethane resin coatings, such as top-coating paints for automobiles, chipping-resistant paints, electrodeposition paints, pre-coated metal / rust-proof steel plates for metal parts such as automobile parts, home appliances / office equipment, paints for building materials, paints for plastics. There has been a demand for a one-component polyurethane resin coating material having excellent weather resistance and not yellowing due to baking in adhesives, adhesiveness-imparting agents, sealing agents and the like.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a coating composition which uses a blocked polyisocyanate as a curing agent and has excellent weather resistance and which does not yellow when baked.

[0005]

Means for Solving the Problems As a result of intensive studies by the present inventors, they have found that the above problems can be solved by combining a specific blocked polyisocyanate, a specific polyol and a compound having a specific group. Came to. That is, the present invention provides a curing agent composition containing an aliphatic or alicyclic block polyisocyanate and a diacylhydrazine compound represented by the following general formula (1) as main components, and the curing agent composition and a resin component. Hydroxyl value 10-300mg
The present invention relates to a one-pack coating composition containing a KOH / g polyol as a main component.

[0006]

Embedded image

(In the formula, R ¹ and R ² represent the same or different hydrogen, an alkyl group, a substituted alkyl group, an aryl group and a substituted aryl group.) The blocked polyisocyanate in the present invention is a known polyisocyanate and a blocking agent. Obtained by the reaction of. Polyisocyanates are derived from aliphatic or cycloaliphatic diisocyanates. The aliphatic diisocyanate preferably has 4 to 30 carbon atoms, and the alicyclic diisocyanate preferably has 8 to 30 carbon atoms. For example, 1,4-tetramethylene diisocyanate, 1,5-pentamethylene diisocyanate, 1,6 -Hexamethylene diisocyanate (hereinafter referred to as HMDI), 2,2
4-trimethyl-1,6-hexamethylene diisocyanate, lysine diisocyanate, 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (isophorone diisocyanate, hereinafter referred to as IPDI), 1,3-bis (isocyanatomethyl) -cyclohexane , 4,4′-dicyclohexylmethane diisocyanate and the like. Among them, HMDI and IPDI are preferable from the viewpoint of weather resistance and industrial availability. These may be used alone or in combination.

Polyisocyanates derived from these aliphatic and alicyclic diisocyanates include, for example, isocyanurate type polyisocyanates, burette type polyisocyanates, urethane type polyisocyanates and the like. Preferred is isocyanurate type polyisocyanate having excellent weather resistance and heat resistance. When synthesizing isocyanurate type polyisocyanate, for example, JP-A-57 / 57
-47321, JP-A-61-111371, Japanese Patent Application No. 5-24152 and the like may be modified with a hydroxyl compound. Examples of the hydroxyl compound used for denaturation include methanol, ethanol,
Isopropanol, monohydroxyl compounds such as phenol, ethylene glycol, propylene glycol,
1,3-butanediol, pentanediol, hexanediol, cyclohexanediol, neopentyl glycol, dihydroxyl compounds such as 2,2,4-trimethyl 1,3-pentanediol, trimethylolpropane, glycerin, pentaerythritol, etc. There are low molecular weight polyhydric alcohols, aliphatic hydrocarbon polyols, polyether polyols, polyester polyols, epoxy resin and other high molecular weight polyhydric alcohols.

Specific examples of the aliphatic hydrocarbon polyols include terminal hydroxyl group-containing polybutadiene and hydrogenated products thereof. Examples of the polyether polyols include polyether polyols obtained by adding alkylene oxides such as ethylene oxide and propylene oxide to a single or mixture of polyhydric alcohols such as glycerin and propylene glycol, and a polytetraol. Polyethylene polyols obtained by reacting methylene glycols and alkylene oxides with polyfunctional compounds such as ethylenediamine and ethanolamine, and so-called polymer polyols obtained by polymerizing acrylamide and the like using these polyethers as a medium. Etc. are included.

As the polyester polyols, for example, a dibasic acid alone selected from the group of carboxylic acids such as succinic acid, adipic acid, sebacic acid, dimer acid, maleic anhydride, phthalic anhydride, isophthalic acid and terephthalic acid. Or a mixture with a polyhydric alcohol selected from the group consisting of ethylene glycol, propylene glycol, diethylene glycol, neopentyl glycol, 1,4-butanediol, 1,6-hexanediol, trimethylolpropane and glycerin, alone or in a mixture. Examples thereof include polyester polyol resins obtained by the condensation reaction of 1) and polycaprolactones obtained by ring-opening polymerization of ε-caprolactone using a polyhydric alcohol.

The epoxy resins include, for example, novolac 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,
Examples thereof include polycarboxylic acid ester type, aminoglycidyl type, halogenated type and resorcin type epoxy resins. Preferably, trimethylolpropane, polyether polyols, polyester polyols are used.

These hydroxyl compounds may be used alone or in combination of two or more kinds. A catalyst is usually used in the isocyanurate-forming reaction for producing an isocyanurate type polyisocyanate. The catalyst used here is generally preferably basic, for example
Examples thereof include secondary ammonium salts, weak organic acid salts thereof, alkyl metal salts of alkylcarboxylic acids, metal alcoholates, and aminosilyl group-containing compounds. The catalyst concentration is usually selected from the range of 10 ppm to 1.0% with respect to the isocyanate compound.

The reaction may or may not use a solvent. When a solvent is used, a solvent inert to the isocyanate group is used. The reaction temperature is usually 20 to 160.
C., preferably 40 to 130.degree. When the reaction reaches the target yield, the catalyst is deactivated by, for example, sulfonic acid, phosphoric acid, etc. to stop the reaction.

Unreacted diisocyanate and solvent can be removed to obtain an isocyanurate type polyisocyanate. Examples of the blocking agent for obtaining the blocked polyisocyanate in the present invention include alcohol type, phenol type, active methylene type, mercaptan type, acid amide type, acid imide type, imidazole type, urea type, oxime type, amine type, imide. System, pyridine compounds, etc.
You may use these individually or in mixture. Examples of more specific blocking agents are shown below.

Alcohols such as methanol, ethanol, propanol, butanol, 2 ethylhexanol, methyl cellosolve, butyl cellosolve, methyl carbitol, benzyl alcohol, cyclohexanol, etc., and phenols such as phenol, cresol, ethylphenol, butylphenol, nonylphenol. , Dinonylphenol, styrenated phenol, hydroxybenzoic acid ester, etc., as active methylene type, dimethyl malonate, diethyl malonate, methyl acetoacetate, ethyl acetoacetate, acetylacetone, etc., mercaptan type, butyl mercaptan, dodecyl mercaptan, etc., acid Examples of amide-based compounds include acetanilide, acetic amide, ε-caprolactam, δ-valerolactam, γ-butyrolactam, and the like. As a system, succinimide,
Maleic imide, imidazole-based, imidazole, 2-methylimidazole, urea-based, urea, thiourea, ethylene urea, etc., oxime-based, formaldoxime, acetoaldoxime, acetoxime, methylethylketoxime, cyclohexanone oxime, etc. Examples of amines include diphenylamine, aniline, and carbazole; examples of imines include ethyleneimine and polyethyleneimine; examples of bisulfites include sodium bisulfite; and examples of pyridines include 2-hydroxypyridine, 2-hydroxyquinoline.

Of these, oxime-based, active methylene-based, phenol-based, and acid amide-based are preferable, and nonylphenol, styrenated phenol, acetoxime, methylethylketoxime, and ε-caprolactam are particularly preferable.
The reaction between the polyisocyanate and the blocking agent can be carried out with or without the presence of a solvent.

In the blocking reaction, an organic metal salt of tin, zinc, lead or the like and a tertiary amine may be used as a catalyst. The reaction can be generally carried out at -20 to 150 ° C, preferably 0 to 100 ° C. If the temperature is 100 ° C. or higher, a side reaction may occur. On the other hand, if the temperature is too low, the reaction rate becomes slow, which is disadvantageous.

The average number of blocked isocyanate functional groups of the blocked polyisocyanate is the number of blocked isocyanate functional groups which one molecule of blocked polyisocyanate has statistically, and is equal to the average number of isocyanate functional groups of the polyisocyanate before blocking. The average number of isocyanate functional groups can be calculated by dividing the product of the number average molecular weight of polyisocyanate and the concentration of isocyanate by the formula weight (42) of isocyanate.

The blocked polyisocyanate of the present invention generally has an average number of functional groups of blocked isocyanate of 2 to
It is selected from the range of 20. It is preferably 3 to 15.
More preferably, it is 4.5-10. When the average number of functional groups of the blocked polyisocyanate is less than 2, the crosslinkability is poor, and it is disadvantageous that baking at a high temperature or for a long time is required to obtain sufficient physical properties such as weather resistance. On the other hand, a blocked polyisocyanate having an average number of functional groups of more than 20 has an extremely high viscosity and is inferior in the smoothness of the coating film, which is not preferable.

The diacylhydrazine compound in the present invention can be obtained, for example, by a transesterification reaction between a carboxylic acid ester and hydrazine, or a reaction between a carboxylic acid chloride or a carboxylic acid anhydride and hydrazine. Examples of the diacylhydrazine-based compound include:
N, N'-diformylhydrazine, N, N'-diacetylhydrazine, N, N'-dipropionylhydrazine,
N, N'-dibutyrylhydrazine, 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'-acetyl) hydrazine, adipic acid-di- (N'-salicyloyl) hydrazine, dodecane Dioil-di- (N'-salicyloyl) hydrazine and the like can be mentioned. Among them, N-salicyloyl-N′-in the following general formula (2), in which at least one of the acyl groups is an alkyl-substituted or unsubstituted salicyloyl group.
Acylhydrazine compounds are preferred. Particularly preferred are N-formyl-N'-salicyloylhydrazine and dodecanedioyl-di- (N'-salicyloyl) hydrazine.

[0021]

[Chemical 4]

(In the formula, R ³ represents hydrogen, an alkyl group or a substituted alkyl group, and R ² represents hydrogen, an alkyl group, a substituted alkyl group, an aryl group or a substituted aryl group.) The diacylhydrazine compound is 0.01 to 20% by weight is added to the block polyisocyanate resin content.
It is preferably 0.05 to 10% by weight. Further, 0.005 to 5% by weight is added to the coating resin component. It is preferably 0.02 to 2% by weight. If it is less than this range, the effect is insufficient, and if it is more than this, good coating properties cannot be obtained.

The curing agent composition of the present invention contains a suitable solvent, if necessary. Examples of the solvent include benzene,
Hydrocarbons such as toluene, xylene, cyclohexane, mineral spirits and naphtha, ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone, esters such as ethyl acetate, -n-butyl acetate and cellosolve acetate.

The one-component coating composition of the present invention is formed by using a polyol and the above-mentioned curing agent composition as main components. The polyol in the present invention is a compound having at least two hydroxyl groups in one molecule, for example, aliphatic hydrocarbon polyols, polyether polyols, polyester polyols, epoxy resins, fluorine-containing polyols and acrylic polyols. And the like.

Specific examples of the aliphatic hydrocarbon polyols include terminal hydroxylated polybutadiene and hydrogenated products thereof. Examples of the polyether polyols include polyether polyols obtained by adding alkylene oxides such as ethylene oxide and propylene oxide to a single or mixture of polyhydric alcohols such as glycerin and propylene glycol, and a polytetraol. Polyethylene polyols obtained by reacting methylene glycols and alkylene oxides with polyfunctional compounds such as ethylenediamine and ethanolamine, and so-called polymer polyols obtained by polymerizing acrylamide and the like using these polyethers as a medium. Etc. are included.

As the polyester polyols, for example, a single dibasic acid selected from the group of carboxylic acids such as succinic acid, adipic acid, sebacic acid, dimer acid, maleic anhydride, phthalic anhydride, isophthalic acid and terephthalic acid is used alone. Or a mixture with a polyhydric alcohol selected from the group consisting of ethylene glycol, propylene glycol, diethylene glycol, neopentyl glycol, 1,4-butanediol, 1,6-hexanediol, trimethylolpropane and glycerin, alone or in a mixture. Examples thereof include polyester polyol resins obtained by the condensation reaction of 1) and polycaprolactones obtained by ring-opening polymerization of ε-caprolactone using a polyhydric alcohol.

The epoxy resins include, for example, novolac 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,
Examples thereof include polycarboxylic acid ester type, aminoglycidyl type, halogenated type, resorcin type epoxy resins and the like, and resins obtained by modifying these epoxy resins with amino compounds, polyamide compounds and the like.

Examples of the fluorinated polyols include, for example, JP-A-57-34107 and JP-A-61-27531.
Examples thereof include copolymers of fluoroolefins, cyclohexyl vinyl ethers, hydroxyalkyl vinyl ethers, monocarboxylic acid vinyl esters and the like disclosed in Japanese Patent Publication No. 1 and the like. Acrylic polyols are obtained by copolymerizing a polymerizable monomer having one or more active hydrogens in one molecule with another monomer copolymerizable with the polymerizable monomer. For example, acrylic acid esters having active hydrogen such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, and 2-hydroxybutyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxymethacrylic acid. Methacrylic acid esters having active hydrogen such as propyl and 2-hydroxybutyl methacrylate, or polyvalent acrylic acid monoester or methacrylic acid monoester of glycerin, acrylic acid monoester or methacrylic acid monoester of trimethylolpropane, etc. A single or a mixture selected from the group of (meth) acrylic acid esters having active hydrogen, and methyl acrylate, ethyl acrylate, isopropyl acrylate, -n-butyl acrylate, 2-ethylhexyl acrylate, etc. Acry Methacrylic acid esters such as acid esters, methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, -n-butyl methacrylate, isobutyl methacrylate, -n-hexyl methacrylate, cyclohexyl methacrylate, lauryl methacrylate, glycidyl methacrylate. And, if necessary, unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid and itaconic acid, unsaturated amides such as acrylamide, N-methylol acrylamide and diacetone acrylamide, and styrene, vinyltoluene, vinyl acetate, It is obtained by copolymerizing a single or a mixture selected from the group of other polymerizable monomers such as acrylonitrile.

Further, polymerizable UV-stable monomers such as 4- (meth) acryloyloxy-2,2,6, exemplified in JP-A-1-261409, JP-A-3-6273, etc. 6-tetramethylpiperidine, 4-
(Meth) acryloylamino-2,2,6,6-tetramethylpiperidine, 1-crotonoyl-4-crotonoyloxy-2,2,6,6-tetramethylpiperidine,
An acrylic polyol resin obtained by copolymerizing 2-hydroxy-4- (3-methacryloxy-2-hydroxypropoxy) benzophenone or the like can also be used.

Among these polyols, particularly preferable are the above-mentioned polyester polyols, fluorine-containing polyols and acrylic polyols. The polyol in the one-pack coating composition of the present invention has a resin component hydroxyl value of 1
It is 0 to 300 mg KOH / g. Resin component hydroxyl value is 1
When the amount is less than 0 mgKOH / g, the crosslinking density of urethane due to the reaction with the isocyanate component decreases, the function of urethane bond cannot be exhibited, and the hydroxyl value of the resin component is 300 m.
If it exceeds gKOH / g, on the contrary, the crosslink density increases, the mechanical properties of the coating film deteriorate, and the hydroxyl group and the isocyanate group do not react completely in some cases, which is not preferable.

The equivalence ratio of the blocked isocyanate group in the blocked polyisocyanate to the hydroxyl group in the polyol in the present invention is determined by the required physical properties of the coating film, but is selected from the range of 0.1 to 2. Is normal. A melamine resin can also be used together. Examples of the melamine resin include hexamethoxymethylol melamine, methyl butylated melamine, and butylated melamine.

In the curing agent composition and the one-component coating composition of the present invention, the following raw materials commonly used in the technical field can be used. For example, quinacridone-based, azo-based, phthalocyanine-based organic pigments, titanium oxide, barium sulfate, calcium carbonate, inorganic pigments such as silica, other, carbon-based pigments, metal foil pigments, pigments such as rust-preventive pigments,
UV absorbers such as hindered amine type, benzotriazole type, benzophenone type, hindered phenol type,
Additives such as phosphorus-based, sulfur-based, hydrazine-based antioxidants, tin-based, zinc-based, amine-based urethane formation catalysts, leveling agents, rheology control agents, pigment dispersants and the like. Further, when mixing the components, a suitable solvent as necessary, for example, benzene, toluene, xylene, cyclohexane, mineral spirits, hydrocarbons such as naphtha, acetone, methyl ethyl ketone, ketones such as methyl isobutyl ketone, ethyl acetate, It can be appropriately selected and used from the group of esters such as -n-butyl acetate and cellosolve acetate according to the purpose and use. These solvents may be used alone or in combination of two or more.

[0033]

EXAMPLES All "parts" in the examples are by weight.
The evaluation was performed according to the following. The degree of yellowing of the coating film is obtained by coating a coating film on a white tile and baking it with a film thickness of 50 μm using a digital automatic colorimeter of Suga Test Instruments Co., Ltd. Is the difference (Δb).

The curability was calculated by calculating the value (gel fraction) of the weight of the undissolved part when the coating film having a thickness of 50 μm was immersed in acetone at 20 ° C. for 24 hours (gel fraction).
90% or more is represented by O. (Production Example 1 of Block Polyisocyanate) A 4-necked flask equipped with a stirrer, a thermometer, a reflux condenser, a nitrogen blowing tube, and a dropping funnel was made into a nitrogen atmosphere, and HMDI6 was used.
00 parts and 30 parts of a polyester polyol “Plaxel 303” (trade name of Daicel Chemical Industries, Ltd.), which is a trihydric alcohol, were charged, and the temperature inside the reactor was maintained at 90 ° C. for 1 hour under stirring to carry out a urethane-forming reaction. Thereafter, the temperature in the reactor was maintained at 60 ° C., the isocyanurate-forming catalyst tetramethylammonium capryate was added, and when the yield reached 54%, phosphoric acid was added to stop the reaction. After filtering the reaction solution, unreacted HMDI was removed using a thin film evaporator. The viscosity of the obtained polyisocyanate at 25 ° C. is 7,000.
The mPas and the isocyanate content were 19.2%, the number average molecular weight was 1100, and the average number of functional groups was 5.1.

Polyisocyanate 100 obtained here
And 33 parts of xylene were placed in a 4-necked flask equipped with a stirrer, a thermometer, a reflux condenser, a nitrogen blowing tube, and a dropping funnel, and the inside of the flask was made a nitrogen atmosphere. Reaction temperature is 5
42 parts of methyl ethyl ketoxime was added dropwise from a dropping funnel so that the temperature did not exceed 0 ° C. It was confirmed that the characteristic absorption of isocyanate in the infrared spectrum had disappeared and the solid content was 80%.
%, Effective isocyanate amount 11%, average number of functional groups 5.1
A block polyisocyanate solution of was obtained.

(Production Example 2 of Block Polyisocyanate) A 4-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen blowing tube was filled with a nitrogen atmosphere and HMDI.
-Based isocyanurate type polyisocyanate "TPA-1
00 ”(trade name of Asahi Kasei, isocyanate content 2
3%, resin content 100%, average number of functional groups 3.2) 100
Parts, ethyl acetoacetate 75 parts, acetylacetone zinc 0.2 parts, and xylene 39 parts were charged, and the temperature inside the reactor was raised to 90 ° C. with stirring, at 90 ° C. until the characteristic absorption of isocyanate in the infrared spectrum disappeared. Held A blocked polyisocyanate solution having a solid content of 80%, an effective isocyanate amount of 11% and an average functional group number of 3.2 was obtained in about 8 hours.

[0037]

Example 1 100 parts of the blocked polyisocyanate obtained in Production Example 1 and an acrylic polyol "Acrydeic A-801" (trade name of Dainippon Ink and Chemicals, resin content hydroxyl value 100 mgKOH / g, resin content 50%) 294
Parts, 1.1 parts of dibutyltin dilaurate, and 0.2 parts of N-formyl-N′-salicyloylhydrazine as a diacylhydrazine compound. To this, a mixture of ethyl acetate / toluene / butyl acetate / xylene / propylene glycol monomethyl ether acetate (weight ratio = 30/30/20/15/5) was added as a thinner, and the mixture was heated to 20 seconds / 20 ° C. with a Ford cup # 4. Adjust and coat with an air spray gun to a dry film thickness of 50 μm.
Test the degree of yellowing of the coating with the coating baked at ℃ for 1 hour,
Curability tests were performed on coatings baked at 130 ° C for 30 minutes. Table 1 shows the test results.

[0038]

Example 2 “Adeka Stab CDA-6” as a diacylhydrazine compound (trade name of Asahi Denka Co., Ltd., dodecanedioyl-di- (N′-salicyloyl) hydrazine)
Example 1 was repeated except that 0.4 part was used. Table 1 shows the test results.

[0039]

Example 3 As the diacylhydrazine compound, “IR
GANOX MD1024 "(trade name of Ciba Geigy,
N, N'-bis (3- (3,5-di-t-butyl-4-
Hydroxyphenyl) propionyl) hydrazine)
Example 1 was repeated except that 4 parts were used. Table 1 shows the test results.

[0040]

Example 4 N, as a diacylhydrazine compound
Example 1 was repeated except that 0.4 part of N'-diacetylhydrazine was used. Table 1 shows the test results.

[0041]

Comparative Example 1 The procedure of Example 1 was repeated except that the diacylhydrazine compound was not used. Table 1 shows the test results.

[0042]

[Table 1]

[0043]

Example 5 100 parts of the blocked polyisocyanate obtained in Production Example 2 and acrylic polyol "Acrydike A-801" (trade name of Dainippon Ink and Chemicals, resin content hydroxyl value 100 mgKOH / g, resin content 50%) 294
Part, N-formyl-as a diacylhydrazine compound
0.2 part of N'-salicyloylhydrazine was compounded. To this, a mixture of ethyl acetate / toluene / butyl acetate / xylene / propylene glycol monomethyl ether acetate (weight ratio = 30/30/20/15/5) was added as a thinner, and the mixture was heated to 20 seconds / 20 ° C. with a Ford cup # 4. The coating was adjusted and coated with an air spray gun to a dry film thickness of 50 μm, and the coating film baked at 140 ° C. for 1 hour was tested for yellowing degree. The coating film baked at 110 ° C. for 30 minutes showed curability. The yellowing degree of the coating film was tested. Table 2 shows the test results
Shown in

[0044]

Comparative Example 2 The procedure of Example 2 was repeated except that the diacylhydrazine compound was not used. The test results are shown in Table 2.

[0045]

[Table 2]

[0046]

EFFECT OF THE INVENTION The polyurethane-based one-component coating composition using the curing agent composition of the present invention has excellent performance such as weather resistance, flexibility, chemical resistance, etc. of polyurethane, and yellowing due to heat or the like. None, pre-coating paint for automobiles, chipping-resistant paint, electrodeposition paint, paint for automobile parts, pre-coated metal / rust-preventing steel plate for metal products such as home appliances / office equipment, paint for building materials, paint for plastics, adhesive Excellent performance as an adhesiveness-imparting agent, a sealing agent, etc.

Claims (6)

[Claims] 1. A curing agent composition comprising an aliphatic or alicyclic block polyisocyanate and a diacylhydrazine compound represented by the following general formula (1) as main components. Embedded image (In the formula, R ¹ and R ² represent the same or different hydrogen, an alkyl group, a substituted alkyl group aryl group, and a substituted aryl group.) 2. The curing agent composition according to claim 1, wherein the diacylhydrazine compound is an N-salicyloyl-N′-acylhydrazine compound represented by the following general formula (2). Embedded image (In the formula, R ³ represents hydrogen, an alkyl group, or a substituted alkyl group, and R ² represents hydrogen, an alkyl group, a substituted alkyl group, an aryl group, or a substituted aryl group.) 3. The blocked polyisocyanate has at least part of a unit derived from hexamethylene diisocyanate as a constituent unit.
A curing agent composition as described. 4. The curing agent composition according to claim 1, wherein the blocked polyisocyanate has an isocyanurate structure. 5. The blocked polyisocyanate has an average number of functional groups of blocked isocyanate of 4.5 per molecule.
The curing agent composition according to claim 1, wherein the curing agent composition is from 10 to 10. 6. A one-pack coating composition comprising the curing agent composition according to claim 1 and a polyol having a resin component hydroxyl value of 10 to 300 mg KOH / g as main components.