JPH08283377A - Curing agent composition and one-pack thermosetting composition - Google Patents

Abstract

PURPOSE: To obtain a curing agent composition which is excellent in both low- temperature curability and thermal yellowing resistance and of which the blocked polyisocyanate itself hardly crystallizes by blending a specified blocked polyisocyanate and a specified component. CONSTITUTION: This curing agent composition contains a blocked polyisocyanate derived from an aliphatic and/or alicyclic diisocyanate and blocked with 10-90% by equivalent of oximes and 90-10% by equivalent of secondary amines and at least one compound selected from the group of compounds containing hydrazide groups represented by formula I [wherein R<1> and R<2> are each H, (substituted) alkyl, or a ring composed of both of them] or semicarbazide groups represented by formula II [wherein R<1> and R<2> are each (substituted) alkyl, or a ring composed thereof], a group of divalent tin compounds, and a group of phosphorous ester compounds. A one-pack thermosetting composition is obtained by using the above composition and a polyhydroxy compound as the main constituents.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a curing agent composition and a one-pack type thermosetting composition, and more particularly, it has excellent low-temperature curability and heat yellowing resistance, and the blocked polyisocyanate itself is difficult to crystallize. The present invention relates to a block polyisocyanate-based curing agent composition and a one-pack type thermosetting composition using the same.

[0002]

2. Description of the Related Art Conventionally, polyurethane resin paints have very excellent wear resistance, chemical resistance, and stain resistance.
A polyurethane resin coating material using a polyisocyanate derived from an aliphatic or alicyclic diisocyanate has further excellent weather resistance, and its demand tends to increase.

However, since the polyurethane resin paint is generally a two-part type, it is extremely inconvenient to use it. That is, a normal polyurethane resin coating consists of two components, a polyol and a polyisocyanate, stored separately,
Must be mixed when painting. 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 conventionally proposed to use a blocked polyisocyanate in which all active isocyanate groups are blocked with a blocking agent. This blocked polyisocyanate does not react with the polyol at room temperature, but when heated, the blocking agent is dissociated, the active isocyanate group is regenerated, and the polyol reacts with the polyol to cause a crosslinking reaction. I can. Therefore, many blocking agents have been studied.

Among them, oximes have been extensively studied and are most commonly used in solution type paints. However, the blocked polyisocyanate using the same generally requires a baking temperature of 140 ° C. or higher. The need for baking at high temperature is
Not only is it disadvantageous in terms of energy, but it also requires heat resistance of the base material, which is a factor limiting its use. In order to improve this problem, JP-A-4-288378 discloses the use of a highly active catalyst, and JP-A-6-287269 discloses the addition of an oxime.
It is disclosed that active methylenes having high low-temperature curability are used as a blocking agent. These methods certainly improve the above-mentioned problems, but on the other hand, the yellowing of the coating film that occurs during baking becomes large, and this yellowing is a factor limiting the application in paints where the appearance is important.

European Patent Publication No. 00962
No. 10 describes blocked polyisocyanates blocked with secondary amines. However, although these blocked polyisocyanates are useful as powder coatings as described in the specifications of the above patents, when they are solution type coatings excellent in surface smoothness and the like, they crystallize particularly at low temperatures. However, there are restrictions such as restrictions on solvent selection and the need to use low resin content.

On the other hand, many proposals have been made for the purpose of improving the heat yellowing of coating materials using blocked polyisocyanates, for example, JP-A-6-93077 and JP-A-5-93077.
-17719 publication etc. However, none of them have reached the point of achieving both low temperature curability and heat yellowing.

[0007]

DISCLOSURE OF THE INVENTION The present invention provides a block polyisocyanate-based curing agent composition which is excellent in both low temperature curability and heat yellowing resistance, and is hard to crystallize the block polyisocyanate itself, and a one-pack type using the same. A thermosetting composition is provided.

[0008]

That is, the present invention provides 10-
Block polyisocyanates derived from aliphatic and / or cycloaliphatic diisocyanates blocked with 90 equivalent% of oximes and 90 to 10 equivalent% of secondary amines and represented by general formula (1) A curing agent composition containing, as an essential component, at least one compound selected from a compound group containing a hydrazide group or a semicarbazide group represented by the general formula (2), a divalent tin compound group, and a phosphite compound group. It is a one-pack type thermosetting composition containing the curing agent composition and a polyhydric hydroxy compound as main components.

[0009]

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[0010]

[Chemical 4]

The present invention will be described in more detail below. The compound containing a hydrazide group used in the present invention, for example, obtained by the reaction of a carboxylic acid chloride and hydrazine or a substituted hydrazine, or by a transesterification reaction of a carboxylic acid ester and a hydrazine or a substituted hydrazine, for example, acetohydrazide, Lauric acid hydrazide, salicylic acid hydrazide, propionic acid-
N, N-dimethylhydrazide, 2-ethylhexanoic acid-N
-Propylhydrazide, adipic acid dihydrazide, sebacic acid dihydrazide, dodecanediohydrazide, isophthalic acid dihydrazide, sebacic acid-bis- (N, N-dimethylhydrazide) and the like can be mentioned.

Examples of the compound containing a semicarbazide group used in the present invention include an isocyanate compound and N,
It can be obtained by reaction with N-di-substituted hydrazine.
Examples of the N, N-disubstituted hydrazine include N, N-dimethylhydrazine, N, N-diethylhydrazine, N,
N-dipropylhydrazine, N, N-diisopropylhydrazine, N, N-distearylhydrazine, N-methyl-N-ethylhydrazine, N-methyl-N-isopropylhydrazine, N-methyl-N-benzylhydrazine, N, Examples thereof include N-di (β-hydroxyethyl) -hydrazine, but the total number of carbon atoms is preferably up to about 20. When the number of carbon atoms is too large, the proportion of hydrazine residues is large, which requires a large amount of compounding for stabilization and also causes a drawback that the compatibility with the one-component coating composition is lowered. Preferred is hydrazine substituted with an alkyl group having 4 or less carbon atoms. Particularly preferred is N, N
-Dimethylhydrazine. These N, N-disubstituted hydrazines may be used alone or in combination of two or more. Examples of the isocyanate compound include tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate (hereinafter HD
I), 2,2,4 (or 2,4,4) -trimethyl-1,6-diisocyanate hexane, lysine diisocyanate, isophorone diisocyanate (hereinafter IP
DI), 1,3-bis (isocyanatomethyl)
-Aliphatic or alicyclic diisocyanates such as cyclohexane, 4,4'-dicyclohexylmethane diisocyanate, xylylene diisocyanate, and tetramethyl xylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 1,4-phenylene diisocyanate, 2,4-tri Examples thereof include aromatic diisocyanates such as diisocyanate and naphthalene diisocyanate, and polyisocyanates derived from these diisocyanates, n-butyl isocyanate, n-hexyl isocyanate, n-octyl isocyanate and phenyl isocyanate. Polyisocyanates derived from diisocyanates include isocyanurate-modified polyisocyanates, burette-modified polyisocyanates, urethane-modified polyisocyanates, and the like.

Of these isocyanate compounds, aliphatic or alicyclic diisocyanates and polyisocyanates derived therefrom are preferred, and HD is more preferred.
I or IPDI and polyisocyanates derived therefrom. Two or more of these isocyanate compounds may be used in combination. Isocyanate compound and N, N-
The reaction with the di-substituted hydrazine can be carried out with or without solvent. When using a solvent, it is necessary to use a solvent which is inert to isocyanate. The reaction can generally be carried out at -20 to 150 ° C, preferably 0
~ 100 ° C. Above 100 ° C, side reactions may occur. On the other hand, if the temperature is too low, the reaction rate becomes slow, which is disadvantageous.

When the isocyanate compound is a di- or polyisocyanate, all of the isocyanate groups may form a semicarbazide group or a part thereof. The remaining isocyanate groups, where only some form semicarbazide groups, may be blocked with active hydrogen compounds.
Examples of active hydrogen compounds include oximes and / or
Alternatively, secondary amines are preferable.

The divalent tin compound used in the present invention may be any divalent tin compound, including organic compounds and inorganic compounds. Examples of the divalent organic tin compound include stannous carboxylate, stannous sulfonate, alkyl stannous compound, and alkyl ether stannous compound. Examples of the stannous carboxylate compound include stannous formate, stannous acetate, stannous propionate, stannous butyrate, stannous isobutyrate, stannous valerate, stannous isovalerate. , Stannous 2-methylbutanoate, stannous pivalate, stannous hexanoate, stannous 4-methylpentanoate, stannous 2-ethylbutanoate, stannous 2,2-dimethylbutanoate,
Stannous heptanoate, stannous 2-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, stannous triacontanate, stannous acrylate, stannous crotonic acid, stannous isocrotonic acid, 3 -Stannous butenoate, stannous methacrylate, stannous angelic acid, stannous oxalate, stannous malonate, stannous succinate, stannous glutarate, stannous adipate, suberin There are stannous acid, stannous azelate, stannous sebacate, stannous maleate and the like. Examples of the stannous sulfonate compound include stannous sulfamate. Examples of the stannous alkyl compound include, for example,
Diethyl tin, di-n-propyl tin, diisopropyl tin,
Examples include di-n-butyltin and diisobutyltin. Examples of the alkyl ether stannous 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,
Examples include stannous sulfide, tin monohydrogen phosphate, tin dihydrogen phosphate, stannous sulfate, and stannous oxide. A divalent organotin compound is preferred, and stannous carboxylate is more preferred.

Two or more kinds of these divalent tin compounds can be used in combination. Examples of the phosphite compound used in the present invention include dialkyl phosphites such as dilauryl hydrogen phosphite, diaryl phosphites such as diphenyl hydrogen phosphite, triethyl phosphite, tributyl phosphite, and tris (2 Ethylhexyl) phosphite, tridodecyl phosphite, tris (tridecyl) phosphite, tristearyl phosphite, distearyl pentaerythritol diphosphite, trilauryl trithiophosphite, bis (tridecyl) pentaerythritol diphosphite, and triphosphite. Alkyl esters,
Triphenyl phosphite, tris (nonylphenyl)
Phosphorous acid triaryl esters such as phosphite, diphenylmono (2-ethylhexyl) phosphite, diphenylmonodecylphosphite, diphenylmono (tridecyl) phosphite, tetraphenyldipropyleneglycol diphosphite, tetraphenyltetra (tridecyl) Pentaerythritol tetraphosphite, tetra (tridecyl) -4,4'-isopropylidene diphenylphosphite, bis (nonylphenyl) pentaerythritol diphosphite, tris (2,4-di-t
-Butylphenyl) phosphite and other phosphorous acid trialkylaryl esters. These can be used in combination of two or more.

In the present invention, at least one compound selected from the group of compounds containing a hydrazide group or a semicarbazide group, the group of divalent tin compounds, and the group of phosphite ester compounds is used. Preferably, two or more compounds selected from two different groups are used in combination. The total addition amount thereof is 0.01 to 10% by weight, preferably 0.1 to 5% by weight, based on the coating resin content.

The blocked polyisocyanates used in the present invention are obtained by reacting the isocyanate groups of polyisocyanates with both oximes and secondary amines in a known manner. The polyisocyanates used in the present invention are derived from aliphatic and / or cycloaliphatic diisocyanates. The aliphatic diisocyanate preferably has 4 to 30 carbon atoms, and the alicyclic diisocyanate preferably has 8 to 30 carbon atoms.
Tetramethylene diisocyanate, pentamethylene diisocyanate, HDI, 2,2,4 (or 2,4
4) -Trimethyl-1,6-diisocyanate hexane, lysine diisocyanate, IPDI, 1,3-bis (isocyanatomethyl) -cyclohexane, 4,4 ′
-Dicyclohexylmethane diisocyanate and the like. Among them, HDI, because of its weather resistance and industrial availability,
IPDI is preferred. These may be used alone or in combination.

Examples of polyisocyanates derived from these aliphatic and alicyclic diisocyanates include 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
No. 473321, JP-A-61-111371, Japanese Patent Application No. 5-24152, etc., modification or urethanization may be carried out using a hydroxyl compound before and / or after the isocyanurate-forming reaction.

It is preferable that the modification with the hydroxyl compound is carried out before the isocyanurate-forming reaction because the compatibility with the main agent is high. As the hydroxyl compound used for modification,
For example, methanol, ethanol, isopropanol,
Monohydroxyl compounds such as phenol, ethylene glycol, propylene glycol, 1,3-butanediol, pentanediol, hexanediol, cyclohexanediol, dimethylolcyclohexane, neopentyl glycol, 2,2,4-trimethyl1,3-pentanediol Such as dihydroxyl compounds, trimethylol propane, glycerin, pentaerythritol and other polyhydric hydroxy compounds, acrylic polyols, polyester polyols, polyether polyols, aliphatic hydrocarbon polyols, epoxy resins, fluorine polyols, etc. There are 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 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. The modification amount is such that the amount of the hydroxyl group of the modifier with respect to the isocyanate group is 0.1 to 20.
Equivalent% is preferred. It is more preferably 0.5 to 15 equivalent%, and still more preferably 1 to 10 equivalent%. The modification with a hydroxyl compound can be generally performed at -20 to 150 ° C. It is preferably 0 to 100 ° C. If the temperature becomes too high, side reactions may occur, while if the temperature becomes too low, the reaction rate becomes slow, which is disadvantageous.

A catalyst is usually used for the isocyanurate-forming reaction. The catalyst used here is generally preferably one having basicity, for example, tetramethylammonium, tetraethylammonium, tetraalkylammonium hydroxide such as tetrabutylammonium, or its acetate, octylate, myristate,
Organic weak acid salts such as benzoate, trimethylhydroxyethylammonium, trimethylhydroxypropylammonium, triethylhydroxyethylammonium, hydroxyalkylammonium hydroxide such as triethylhydroxypropylammonium, and its acetate, octylate, myristate, Organic weak acid salts such as benzoate, alkali metal salts of alkylcarboxylic acids such as acetic acid, caproic acid, octylic acid and myristic acid, and metal salts of the above alkylcarboxylic acids such as tin, zinc and lead, hexamethylene disilazane, etc. Aminosilyl machine-containing compounds and the like. The catalyst concentration is usually selected from the range of 10 ppm to 1.0% with respect to the isocyanate compound.

The reaction can be carried out with or without a solvent. When using a solvent, it is necessary to use a solvent which is inert to the isocyanate group. The reaction temperature is usually 20
˜160 ° C., preferably 40˜130 ° C. When the reaction reaches the target yield, the catalyst is deactivated by, for example, sulfonic acid, phosphoric acid, etc. to stop the reaction.

Unreacted materials and solvent are removed to obtain polyisocyanate. The oximes used in the present invention include:
For example, there are formaldoxime, acetoaldoxime, acetoxime, methylethylketoxime, cyclohexanoneoxime, etc., and acetoxime and methylethylketoxime are particularly preferable. These may be used alone or in combination.

The oximes are used in an amount of 10 to 90 equivalent% based on the isocyanate groups of polyisocyanate. Preferably 20 to 80 equivalent%, more preferably 30 to 70.
Equivalent%. Examples of the secondary amines used in the present invention include dimethylamine, diethylamine and di-amine.
Secondary amine bonded to primary carbon such as n-propylamine, ethylmethylamine, diisopropylamine, di-
Secondary amines bound to secondary carbons such as sec-butylamine, dicyclohexylamine, isopropylcyclohexylamine, secondary amines bound to tertiary carbons such as di-t-butylamine, other secondary amines such as isopropylethylamine There are aliphatic secondary amines such as amines and diarylamines such as diphenylamine and carbazole. Preferred is a secondary amine bonded to a secondary carbon. Particularly preferred is diisopropylamine.

The secondary amine-based blocking agent is 90 to 10 equivalent% based on the isocyanate group of polyisocyanate.
Used. It is preferably 80 to 20 equivalent%, more preferably 70 to 30 equivalent%. If too much oxime is used as the blocking agent, low-temperature curability is deteriorated, which is not preferable. Further, if the amount of secondary amines is too large, the blocked polyisocyanate tends to crystallize, which is not preferable.

The total amount of oximes and secondary amines is
80 to the isocyanate group of polyisocyanate
120 equivalent% is preferred. More preferably 90 to 110
Equivalent%. A part of the polyisocyanate may be blocked with a blocking agent other than these two types of blocking agents, such as alcohols, phenols, acid amides, imidazoles, pyridines, mercaptans and active methylenes. The amount of the other blocking agent used is preferably 30 equivalent% or less with respect to the isocyanate group of the polyisocyanate.

Blocking with two types of blocking agents may be carried out simultaneously, or free isocyanate groups remaining after first blocking with one blocking agent may be blocked with the other blocking agent. The blocking reaction can be performed with or without the presence of a solvent. When using a solvent, it is necessary to use a solvent which is inert to the isocyanate group.

A catalyst may be used in the blocking reaction. As the catalyst, for example, dibutyltin diacetate, dibutyltin dilaurate, tetrabutyldiacetoxystannoxane, organotin compounds such as tin octylate, organozinc compounds such as zinc octylate, organolead compounds such as lead octylate, etc. Organic metal compounds, metal alcoholates such as sodium methylate, triethylenediamine, 1,8-
And tertiary amines such as diazabicyclo [5,4,0] undecene-7.

The blocking reaction is generally -20 to 150.
It can be carried out at a temperature of 0 ° C, preferably 0 to 100 ° C. If the temperature is 150 ° C or higher, a side reaction may occur. On the other hand, if the temperature is too low, the reaction rate becomes low, which is disadvantageous. It is preferably blocked so as to be substantially free of isocyanate groups. The polyhydric hydroxy compound 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.

Specific examples of the aliphatic hydrocarbon polyols include, for example, terminally 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 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.

Examples of the epoxy resins include novolac type, β-methylepichloro 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 exemplified in JP-A-1-261409, JP-A-3-6273, etc., such as 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,
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 hardener 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 and sulfur-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, alcohols such as isopropanol, butanol and butyl cellosolve according to the purpose and application. These solvents may be used alone or in combination of two or more.

[0043]

EXAMPLES The measuring methods in Examples and Comparative Examples are shown below.
“Part” is based on weight. The gel fraction represents the weight residual rate (%) after the cured coating film was immersed in acetone for 24 hours. Yellowing degree Δb is a digital automatic colorimetric color difference meter (Suga Test Instruments Co., Ltd.)
The difference (increased amount) between the b value measured in (manufacturing) and the b value of the coating film before baking is shown.

Reference Example 1 A 4-necked flask equipped with a stirrer, a thermometer, a reflux condenser, a nitrogen blowing tube, and a dropping funnel was placed in a HDI-based urethane-modified isocyanurate type polyisocyanate "Duranate MFA-90X" (Asahi Kasei). Industrial trade name, isocyanate content 16.4%,
100 parts of resin content 90%) and 73 parts of xylene were charged, and the inside of the flask was made a nitrogen atmosphere. A mixed solution of 18 parts of methyl ethyl ketoxime and 21 parts of diisopropylamine was added dropwise thereto so that the reaction temperature did not exceed 50 ° C. After confirming that the characteristic absorption of isocyanate in the infrared spectrum had disappeared, a blocked polyisocyanate solution having a resin content of 60% and an effective isocyanate amount of 7.8% was obtained. This curing agent composition did not crystallize even after being stored at 5 ° C. for 2 weeks and maintained a solution state.

[0045]

Example 1 0.8 part of tris (tridecyl) phosphite (manufactured by Johoku Chemical Co., Ltd., trade name JP333E) was added to 100 parts of the blocked polyisocyanate obtained in Reference Example 1 to obtain a curing agent composition. .

[0046]

[Example 2] The curing agent composition obtained in Example 1 and an acrylic polyol (trade name of ACNIDEK A-8 manufactured by Dainippon Ink Co., Ltd.
01, resin content hydroxyl value 100 mgKOH / g, solid content 5
0%) was blended so that the blocked isocyanate groups and hydroxyl groups would be equivalent. At this time, the blending amount of tris (tridecyl) phosphite is 0.5% with respect to the coating resin content.
Was equivalent to. To this, dibutyltin dilaurate was added as a catalyst to 0.5% of the coating resin content, and as a thinner, ethyl acetate / toluene / butyl acetate /
A mixed solution of xylene / propylene glycol monomethyl ether acetate (weight ratio = 30/30/20/15/5) was added, and the temperature was adjusted to 20 seconds / 20 ° C. with Ford cup # 4. The obtained coating solution is applied with an air spray gun to a dry film thickness of 50 μm, and 110, 120
The coating film physical properties were measured by baking for 30 minutes in an oven maintained at 60 ° C and 160 ° C. Also, a part of the coating solution was put in a closed container at 40 ° C for storage stability test.
Stored in. After being stored for 4 weeks, the product that can be coated was evaluated as ◯. The obtained results are shown in Table 2.

[0047]

Examples 3 to 8 The additives shown in Table 2 were added to 100 parts of the blocked polyisocyanate obtained in Reference Example 1 to obtain a curing agent composition. The curing agent composition obtained here was made into a paint in the same manner as in Example 2, and the physical properties of the coating film and the storage stability test were conducted. The obtained results are shown in Table 2.

In the table, HN-130 is a semicarbazide group-containing compound (manufactured by Nippon Hydrazine Industry Co., Ltd.) diluted with methanol to a resin content of 25%, and T2EH is tin 2-ethylhexanoate, J
P333E is tris (tridecyl) phosphite (manufactured by Johoku Chemical Co., Ltd.).

[0049]

Examples 9 to 12 Block polyisocyanate solutions were obtained in the same manner as in Reference Example 1 with the formulations shown in Table 1. This curing agent composition did not crystallize even after being stored at 5 ° C. for 2 weeks and maintained a solution state. The additives shown in Table 2 were added to this to obtain a curing agent composition. The curing agent composition obtained here was used in Example 2.
It was made into a paint in the same manner as above, and the physical properties of the coating film and the storage stability test were conducted. The obtained results are shown in Table 2.

In the table, MFA-90X is an HDI-based urethane-modified isocyanurate type polyisocyanate,
Duranate MFA-90X (Made by Asahi Kasei), TPA
-100 is an HDI pure isocyanurate type polyisocyanate, Duranate TPA-100 (manufactured by Asahi Chemical Industry Co., Ltd.), and T-1890 is an IPDI pure isocyanurate type polyisocyanate (manufactured by Huls).

[0051]

[Comparative Example 1] A blocked polyisocyanate solution was obtained in the same manner as in Reference Example 1 with the formulations shown in Table 1. When this blocked polyisocyanate solution was stored at 5 ° C. for 2 weeks, crystallization occurred and it lost its fluidity and was not suitable for a solution type paint.

[0052]

[Comparative Example 2] A blocked polyisocyanate solution was obtained in the same manner as in Reference Example 1 with the formulations shown in Table 1. The obtained blocked polyisocyanate solution did not crystallize even after being stored at 5 ° C. for 2 weeks and maintained a solution state. The additives shown in Table 2 were added to this to obtain a curing agent composition.

This curing agent composition was made into a paint in the same manner as in Example 2 and the physical properties of the coating film and the storage stability test were conducted.
The obtained results are shown in Table 2. As shown in Table 2, the low temperature curability was low, which was not preferable.

[0054]

[Comparative Example 3] The blocked polyisocyanate solution obtained in Reference Example 1 was made into a coating material as it was in the same manner as in Example 2 without adding any additives, and the physical properties of the coating film and the storage stability test were conducted. The obtained results are shown in Table 2. As shown in Table 2, heat yellowing resistance was poor, which was not preferable.

[0055]

[Table 1]

[0056]

[Table 2]

[0057]

EFFECTS OF THE INVENTION According to the present invention, it is possible to achieve both low temperature curing property and heat yellowing resistance which have not been achieved by the conventional non-yellowing one-pack type polyurethane paint mainly composed of polyol and block polyisocyanate. In addition, the block polyisocyanate does not crystallize itself and can exist stably in a solution state. It can be used in top-coating paints for automobiles, chipping-resistant paints, electrodeposition paints, paints for automobile parts, home appliances, office equipment, etc. Excellent performance as pre-coated metal / rust-proof steel plate for metal products, coating material for building materials, coating material for plastics, adhesives, adhesion promoters, sealing agents, etc.

Claims (7)

[Claims] 1. (a) blocked with 10 to 90 equivalent% of oximes and 90 to 10 equivalent% of secondary amines,
A compound group containing a blocked polyisocyanate derived from an aliphatic and / or alicyclic diisocyanate, and (b) a hydrazide group represented by the general formula (1) or a semicarbazide group represented by the general formula (2). A curing agent composition comprising at least one compound selected from the group of tin compounds and the group of phosphite compounds. Embedded image Embedded image 2. The curing agent composition according to claim 1, wherein the blocked polyisocyanate has at least a part derived from hexamethylene diisocyanate as a constituent unit. 3. The curing agent composition according to claim 1, wherein the polyisocyanate constituting the blocked polyisocyanate is an isocyanurate type polyisocyanate. 4. The curing agent composition according to claim 1, wherein the polyisocyanate constituting the blocked polyisocyanate is an isocyanurate type polyisocyanate modified with a hydroxyl compound. 5. The curing agent composition according to claim 1, wherein the secondary amines are secondary amines in which carbon bonded to nitrogen is secondary carbon. 6. The curing agent composition according to claim 1, wherein the secondary amine is diisopropylamine. 7. A curing agent composition according to claim 1, (A),
(B) A polyhydric hydroxy compound as a main component, a one-pack type thermosetting composition.