JPH09255915A - Thermosetting composition and production thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermosetting composition having better cold-setting properties and storage stability than conventional non-yellowing one-pack type polyurethane coating composition, and a method for producing the composition. SOLUTION: The composition is obtained by heating a composition comprising a blocked polyisocyanate containing an active methylene group and a polyhydroxy compound in the presence of a monofunctional and/or bifunctional compound containing active hydrogen, e.g. a mono- or dihydric alcohol, at 40-150 deg.C while regulating the reaction system so as to have a nonvolatile content of 10-90wt.%. The composition has excellent performances when used as a topcoating, intercoating, chipping-resistant coating, or electrodeposition coating composition for motor vehicles, coating composition for automotive parts, automotive repair coating composition, coating composition for precoated metals, and anticorrosive steel plates for metallic products, e.g. household electric appliances and office machine, coating composition for building materials or for plastics, adhesive, adhesion promoter sealant, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermosetting composition and a method for producing the same, more specifically, a thermosetting composition having high low-temperature curability and greatly improved storage stability, and a method for producing the same. It is about.

[0002]

2. Description of the Related Art Conventionally, polyurethane resin paints have very excellent abrasion resistance, chemical resistance and stain resistance,
Polyurethane resin paints using polyisocyanates derived from aliphatic or cycloaliphatic diisocyanates are more excellent in weather resistance, and the demand for them tends to increase.

However, polyurethane resin coatings are generally inconvenient to use because they are two-packs. That is, a normal polyurethane resin coating consists of two components, a polyol and a polyisocyanate, stored separately,
Must be mixed when painting. Also, once mixed,
The present situation is that the paint 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. In addition, it is necessary to sufficiently clean the coating machine and the coating tank at the end of the work, so that the work efficiency is significantly reduced.

Heretofore, in order to improve the above disadvantages, it has been proposed to use a blocked polyisocyanate in which all active isocyanate groups are blocked with a blocking agent. Although this blocked polyisocyanate does not react with the polyol at room temperature, the blocking agent is dissociated by heating to regenerate the active isocyanate group and react with the polyol to cause a cross-linking reaction. I can. Therefore, many blocking agents have been studied, and for example, phenol, methylethylketoxime, etc. are considered to be typical blocking agents.

However, in blocked polyisocyanates using these blocking agents, generally, 14
A high baking temperature of 0 ° C. or higher is required. The need for baking at such a high temperature is not only disadvantageous in terms of energy, but also requires heat resistance of the substrate, which is a factor limiting its use. In addition, Japanese Patent Laid-Open No. 3-17116
In the publication, a pyridine-based block polyisocyanate is described as a low temperature baking type block polyisocyanate. However, although the one-component paint using such a low temperature baking type block polyisocyanate can be baked at a low temperature, it is inferior in storage stability, and its use is greatly restricted.

On the other hand, as a low temperature baking type block polyisocyanate, a block polyisocyanate using an active methylene compound such as acetoacetic acid ester and malonic acid diester has been studied. For example, JP
2-116420 discloses a blocked polyisocyanate obtained by blocking buret type polyisocyanate derived from hexamethylene diisocyanate with acetoacetic acid ester. In addition, JP-A-60-14
Japanese Patent No. 9572 describes a blocked polyisocyanate obtained by blocking isocyanurate type polyisocyanate derived from hexamethylene diisocyanate with acetoacetic acid ester. Also, JP-A-57-121
In 065 publication, blocked polyisocyanates blocked with malonic acid diesters are described. However, although the thermosetting composition using these active methylene-based blocked polyisocyanates as a curing agent has excellent low-temperature curability, it has been inevitably stored at low temperature because of poor storage stability. On the other hand, the present inventors have filed Japanese Patent Application No. 7-3
As shown in 1953, it has been found that a thermosetting composition containing a specific active methylene-based blocked polyisocyanate and a specific alcohol is excellent in storage stability. However, in order to obtain sufficient storage stability, it is necessary to add a large amount of alcohol, and the degree of freedom in coating composition is low, and improvement has been earnestly desired.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a thermosetting composition having a high low temperature curability and a very excellent storage stability.

[0008]

As a result of intensive studies to solve the above problems, the present inventors have found that an active methylene block polyisocyanate, a polyvalent hydroxy compound, and a monofunctional and / or difunctional compound. It was found that a thermosetting composition obtained by heating a composition containing an active hydrogen-containing compound in a temperature range of 40 to 150 ° C. can solve the above problems, and has completed the present invention.

That is, according to the present invention, a composition containing (A) an active methylene block polyisocyanate and (B) a polyhydroxy compound is mixed with (C) a monofunctional and / or difunctional active hydrogen-containing compound. Below, the nonvolatile content is 10
A thermosetting composition suitable for coating, which is obtained by heating in a temperature range of 40 to 150 ° C. in a state of 90% by weight, (C) a monofunctional and / or difunctional active hydrogen-containing compound. Relates to the above thermosetting composition in which is an alcohol. The present invention also provides (C) a monofunctional and / or a composition containing (A) an active methylene-based blocked polyisocyanate and (B) a polyhydroxy compound.
Or a thermosetting composition suitable for coating, which comprises heating in the temperature range of 40 to 150 ° C. in the presence of a non-volatile content of 10 to 90% by weight in the coexistence of a bifunctional active hydrogen-containing compound. And (C) the monofunctional and / or difunctional active hydrogen-containing compound is an alcohol, the above-mentioned thermosetting composition.

The present invention will be described in more detail below. The (A) active methylene-based blocked polyisocyanate used in the present invention can be obtained by reacting a polyisocyanate with an active methylene-based compound by a known method. The polyisocyanates are derived from aliphatic, cycloaliphatic and / or aromatic diisocyanates. As the aliphatic diisocyanate, those having 4 to 30 carbon atoms are alicyclic,
The aromatic diisocyanate preferably has 8 to 30 carbon atoms, and examples thereof include tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate (hereinafter referred to as HDI), 2,2,4.
(Or 2,4,4) -trimethyl-1,6-diisocyanate hexane, lysine diisocyanate, isophorone diisocyanate (hereinafter referred to as IPDI), 1,
3-bis (isocyanatomethyl) -cyclohexane,
4,4′-dicyclohexylmethane diisocyanate,
Examples include tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, tolidine diisocyanate, xylylene diisocyanate and the like. These may be used alone or in combination. Aliphatic diisocyanates and alicyclic diisocyanates are preferable, and among them, HDI and IPDI are preferable because of their weather resistance and industrial availability.
Is most preferred.

Polyisocyanates derived from these diisocyanates include, for example, isocyanurate type polyisocyanates, burette type polyisocyanates, urethane type polyisocyanates and alohanate type polyisocyanates. Preferred is isocyanurate type polyisocyanate having excellent weather resistance and heat resistance.

The average number of functional groups of polyisocyanate is 2 to
15 is preferred. It is more preferably 3 to 12, and even more preferably 4.5 to 10. If the average number of functional groups is less than 2, the crosslinkability will be poor, and in order to obtain sufficient solvent resistance, weather resistance, etc., baking at high temperature or for a long time is required. On the other hand, 15
If it exceeds the above range, it is necessary to add a large amount of a leveling agent or the like in order to obtain the smoothness of the coating film.

The average number of functional groups is the average value of the number of isocyanate groups bonded to one molecule of polyisocyanate, and is the product of the number average molecular weight and the isocyanate concentration divided by the formula weight (42) of isocyanate. . Here, the isocyanate concentration is a weight ratio of the isocyanate group (NCO) to the polyisocyanate. When synthesizing an isocyanurate type polyisocyanate, for example, JP-A-57-47321 and JP-A-61-11137 are used.
As disclosed in Japanese Patent Laid-Open No. 1-3112969 and Japanese Unexamined Patent Publication No. 6-312969, a hydroxyl compound can be used for modification, that is, urethanization, before, during and / or after the isocyanurate-forming reaction.

Examples of the hydroxyl compound used for the modification include monohydroxyl compounds such as methanol, ethanol, isopropanol and phenol, ethylene glycol, propylene glycol, 1,3-butanediol, pentanediol, hexanediol, cyclohexanediol and dihydroxylamine. Methylol cyclohexane, neopentyl glycol, 2,2,4-trimethyl 1,3
-Dihydroxyl compounds such as pentanediol, polyhydric hydroxy compounds such as trimethylolpropane, glycerin and pentaerythritol, acrylic polyols, polyester polyols, polyether polyols,
Examples include polyols such as aliphatic hydrocarbon polyols, epoxy resins, and fluorine polyols.

Specific examples of the aliphatic hydrocarbon polyols include terminal hydroxylated polybutadiene and hydrogenated products thereof. Further, as the polyether polyols, for example, polyether polyols obtained by adding a single or mixture of polyhydric alcohols such as glycerin and propylene glycol, ethylene oxide, alkylene oxides such as propylene oxide, Polytetramethylene glycols, ethylenediamine, alkylene oxide,
Examples include polyether polyols obtained by reacting polyfunctional compounds such as ethanolamines, and so-called polymer polyols obtained by polymerizing acrylamide or the like using these polyethers as a medium.

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

Examples of the epoxy resins include 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, polyvalent carboxylic acid. Ester type, aminoglycidyl type,
Epoxy resins such as halogenated type and resorcinol type are exemplified.

Preferably, trimethylolpropane, polyether polyols and 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 generally be carried out at -20 to 150 ° C. Preferably 0
100 ° C. If the temperature becomes too high, side reactions may occur, whereas 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, myristic acid, and tin of the above alkylcarboxylic acids Zinc, metal salts such as lead, aminosilyl group-containing compounds such as hexamethyldisilazane 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 a solvent is used, it is necessary to use a solvent inert to isocyanate groups. The reaction temperature is usually 2
It is 0-160 ° C, preferably 40-130 ° C. When the reaction reaches the target yield, the reaction is stopped by deactivating the catalyst with, for example, sulfonic acid, phosphoric acid, etc., and unreacted materials and solvent are removed to obtain polyisocyanate.

The active methylene compounds used in the present invention are roughly classified into malonic acid diester compounds and acetoacetic acid ester compounds. Malonic acid diester compounds include dimethyl malonate, diethyl malonate, diisopropyl malonate, di-n-propyl malonate, di-n-butyl malonate, ethyl n-butyl malonate, methyl n-butyl malonate, malonic acid. There are ethyl t-butyl, methyl t-butyl malonate, diethyl methylmalonate, dibenzyl malonate, diphenyl malonate, benzylmethyl malonate, ethylphenyl malonate, t-butylphenyl malonate, isopropylidene malonate, etc., These can also be used together.

Examples of the acetoacetic acid ester compounds include methyl acetoacetate, ethyl acetoacetate, isopropyl acetoacetate, n-propyl acetoacetate, t-butyl acetoacetate, n-butyl acetoacetate, benzyl acetoacetate and phenyl acetoacetate. Yes, these can be used together. A malonic acid diester compound and an acetoacetic acid ester compound may be used in combination.

Instead of reacting a part of the isocyanate groups of polyisocyanate with an active methylene compound, for example, alcohols, phenols, acid amides, imidazoles, pyridines, mercaptans, oximes, amines, etc. It may be reacted with a compound. The amount of these compounds used is preferably 30 equivalent% or less based on the isocyanate groups of the polyisocyanate.

The reaction between the polyisocyanate and the active methylene compound can be carried out with or without the presence of a solvent. When a solvent is used, it is preferable to use a solvent which is inactive to the isocyanate group. A catalyst may be used, and examples of the catalyst include dibutyltin diacetate, dibutyltin dilaurate, tetrabutyldiacetoxystannoxane, organotin compounds such as tin octylate, organic zinc compounds such as zinc octylate, and octylic acid. Organic metal compounds such as lead compounds such as lead, metal alcoholates such as sodium methylate, triethylenediamine, 1,8-
Examples include tertiary amines such as diazabicyclo [5,4,0] undecene-7.

The reaction between the polyisocyanate and the active methylene compound can be generally carried out at -20 to 150 ° C, preferably 0 to 100 ° C. If it exceeds 150 ° C, a side reaction may occur. On the other hand, if the temperature is too low, the reaction rate becomes slow, which is disadvantageous. It is preferable to react so that substantially active isocyanate groups are eliminated.

The polyhydric hydroxy compound (B) used in the present invention is a compound having at least two hydroxyl groups in one molecule, and examples thereof include aliphatic hydrocarbon polyols, polyether polyols and polyester polyols. , Epoxy resins, fluorine-containing polyols, acrylic polyols and the like. Specific examples of the aliphatic hydrocarbon polyols include, for example, end-hydroxylated polybutadiene and hydrogenated products thereof. Further, as the polyether polyols, for example, polyether polyols obtained by adding a single or mixture of polyhydric alcohols such as glycerin and propylene glycol, ethylene oxide, alkylene oxides such as propylene oxide, Polytetramethylene glycols, further polyether polyols obtained by reacting alkylene oxide with a polyfunctional compound such as ethylenediamine and ethanolamines,
And so-called polymer polyols and the like obtained by polymerizing acrylamide and the like using these polyethers as a medium.

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

The epoxy resins include, for example, 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, polyvalent carboxylic acid. Ester type, aminoglycidyl type,
Examples thereof include halogenated type and resorcin type epoxy resins, 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.
There are copolymers such as fluoroolefins, cyclohexyl vinyl ethers, hydroxyalkyl vinyl ethers, vinyl monocarboxylic acid esters, and the like, which are disclosed in Japanese Patent Publication No. 1 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, 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 acrylic acid monoesters or methacrylic acid monoesters of glycerin, acrylic acid monoesters or methacrylic acid monoesters of trimethylolpropane, etc. (Meth) acrylic acid ester having a valent active hydrogen, or alone or a mixture selected from the group of monomers and the like obtained by ring-opening polymerization of ε-caprolactone to the active hydrogen of these (meth) acrylic acid ester, acrylic Acrylic esters such as methyl, ethyl acrylate, isopropyl acrylate, -n-butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, -n-butyl methacrylate, methacrylic acid Acid isobutyl, methacrylate-n-hexyl methacrylate, cyclohexyl methacrylate, lauryl methacrylate, glycidyl methacrylate, and other methacrylic acid esters, acrylic acid, methacrylic acid, maleic acid, unsaturated carboxylic acids such as itaconic acid, acrylamide, N- Unsaturated amides such as methylol acrylamide and diacetone acrylamide, other polymerizable monomers such as styrene, vinyltoluene, vinyl acetate and acrylonitrile, and JP-A-1-261409 and JP-A-3-627. No. 3, 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, 2-hydroxy-4- (3- Methacryloxy-2
-Hydroxypropoxy) benzophenone and the like, which are obtained by copolymerizing with a single or a mixture selected from the group of polymerizable UV-stable monomers.

Among these, particularly preferable are the above-mentioned polyester polyols, fluorine-containing polyols and acrylic polyols. The polyvalent hydroxy compound used in the present invention has a resin component hydroxyl value of 10 to 300 mg.
It is preferably KOH / g. Resin component hydroxyl value is 1
If it is less than 0 mgKOH / g, the crosslink density decreases,
Acid resistance, weather resistance, etc. are reduced, and the hydroxyl value of the resin component is 300 m
If it exceeds gKOH / g, on the contrary, the crosslink density tends to increase, and the mechanical properties of the coating film tend to deteriorate.

The (C) monofunctional and / or difunctional active hydrogen-containing compound used in the present invention is at least a part thereof when the thermosetting composition of the present invention is coated and heat cured. Is volatilized and released from the composition, and examples thereof include alcohols, phenols, acid amides, imidazoles, pyridines, mercaptans, oximes and amines. Among them, alcohols, phenols and oximes are preferable, and alcohols are particularly preferable. These monofunctional and / or difunctional active hydrogen-containing compounds are not particularly limited,
The boiling point is preferably 250 ° C. or lower. It is more preferably 50 to 220 ° C., and even more preferably 60 to 20 ° C.
0 ° C. If the boiling point is too high, it will be difficult to volatilize from the coating film during thermosetting, which causes a decrease in curability. On the other hand, if it is too low, it may cause armpits.

Examples of alcohols having such boiling points include, as monoalcohols, for example, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, t-butanol, pentanol and hexanol. , Heptanol, octanol, 2-ethyl-1-hexanol, n-butyl cellosolve, propylene glycol monomethyl ether, cyclohexanol, benzyl alcohol and the like. Examples of dialcohols include ethylene glycol, diethylene glycol, propylene glycol, propanediol, butanediol and the like. Examples of phenols include phenol, cresol, xylenol, carvacrol, thymol,
Examples include catechol. Examples of the oximes include acetoxime, methylethylketoxime, cyclohexanone oxime and the like.

The addition amount of the (C) monofunctional and / or difunctional active hydrogen-containing compound can be arbitrarily selected, but it is 10 to the blocked isocyanate group.
500 equivalent% is preferred. More preferably 20-400
Equivalent%, more preferably 30 to 300 equivalent%. In the present invention, the equivalent ratio of the blocked isocyanate group in the (A) active methylene-based blocked polyisocyanate to the hydroxyl group of the (B) polyvalent hydroxy compound is determined depending on the required physical properties of the coating film. It is usually selected from the range of 1-2.

A melamine resin can also be used in combination. Examples of the melamine resin include hexamethoxymethylol melamine, methyl butylated melamine, and butylated melamine. In the thermosetting composition of the present invention, the following additives, pigments, solvents and the like 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, hydrazide-based antioxidants, tin-based, zinc-based, amine-based urethane formation catalysts, leveling agents, rheology control agents, pigment dispersants and the like. Also, if necessary, suitable solvents, for example, benzene, toluene, xylene, cyclohexane, mineral spirits, hydrocarbons such as naphtha, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, n-butyl acetate And esters such as cellosolve acetate and the like, depending on the purpose and application. These solvents may be used alone or in combination of two or more.

In the present invention, a composition containing (A) an active methylene-based blocked polyisocyanate and (B) a polyhydroxy compound is added in the presence of (C) a monofunctional and / or difunctional active hydrogen-containing compound. By heating to
Storage stability is improved. In the conventional method for improving the storage stability by allowing (C) to coexist with (A) and (B), the reaction between (A) and (C), which is a competitive reaction, is caused. The reaction rate of (B) was reduced to suppress thickening and improve storage stability.

On the other hand, the present inventors (A) and (B)
It was found that both the reaction of (1) and the reaction of (A) and (C) are equilibrium reactions. That is, (A) and (B)
When (C) is co-existing and heated in (1), thickening occurs due to the reaction of (A) and (B) in the initial stage of the reaction, but there is an equilibrium point at some point, and further thickening hardly occurs. In addition, the reaction between (A) and (B) makes it possible to have this equilibrium point at a reaction rate lower than that at which the composition gels, and the storage stability of the composition can be improved by heating. He found that control was possible.

That is, the composition obtained by heating (A) and (B) with (C) coexisting and reacting to the vicinity of the above equilibrium point is:
There is almost no increase in viscosity when stored, and storage stability is greatly improved. Thus, the fact that the reaction of (A) and (B) and the reaction of (A) and (C) have an equilibrium point means that both of these two reactions are mainly transesterification reactions, and urethane This is because the chemical reaction does not occur apparently.

When (C) coexists in (A) and (B) and is heated, other components such as a solvent are not particularly limited, and all or some of the other components may coexist and react. Alternatively, other components may be mixed after the reaction. It is preferable to heat in the temperature range of 40 to 150 ° C. More preferably, it is 55-130 degreeC. More preferably, it is 60 to 110 ° C. If it exceeds 150 ° C, a side reaction may occur, while if it is less than 40 ° C, the reaction rate becomes slow, which is disadvantageous. Considering the productivity, it is necessary to select the heating temperature at which the desired storage stability is obtained within 24 hours.

When the composition containing the (A) active methylene block polyisocyanate and the (B) polyhydric hydroxy compound is heated, the nonvolatile content is 10 to 90% by weight. It is preferably 15 to 85% by weight, and more preferably 20.
~ 80% by weight. When the non-volatile content is less than 10% by weight, the amount of volatile components increases, which causes a global environmental problem, and when it exceeds 90% by weight, the viscosity of the composition tends to increase. Here, the non-volatile components include (A) the resin component of the active methylene-based block polyisocyanate and (B) the resin component of the polyvalent hydroxy compound, and the resin component of other resins added as necessary, and pigments and the like. It is the sum of non-volatile components.

[0040]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples. “Parts” in Examples and Comparative Examples are based on weight. (Curability) A cured coating film that has been baked for 30 minutes in an oven maintained at 100 ° C or 120 ° C is immersed in acetone for 24 hours, and a product whose weight residual rate (%) is less than 90% is x, 90% or more. The thing of No. was made into O, and the thing of 95% or more was made into ◎. (Storage stability) The viscosity change of a coating solution of 20 seconds / 20 ° C. stored in Ford cup # 4 at 40 ° C. for 1 month was ±
◎ within 5 seconds, ○, within ± 10 seconds, ± 10
Items that exceeded the second were marked with x.

[0041]

[Production Example 1] (Production of polyisocyanate) A 4-necked flask equipped with a stirrer, a thermometer, a reflux cooling tube, and a nitrogen blowing tube was filled with a nitrogen atmosphere to obtain HDI100.
Was charged, the temperature inside the reactor was maintained at 60 ° C. with stirring, tetrabutylammonium acetate was added, and the yield was 23.
When the percentage reached, phosphoric acid was added to stop the reaction. After filtering the reaction solution, unreacted HDI was removed using a thin film evaporator to obtain polyisocyanate-I having a viscosity at 25 ° C. of 1700 mPas and an isocyanate content of 23.0%.

[0042]

[Production Example 2] (Production of polyisocyanate) A 4-necked flask equipped with a stirrer, a thermometer, a reflux cooling tube, and a nitrogen blowing tube was filled with a nitrogen atmosphere to obtain HDI100.
And 3.3 parts of trimethylolpropane, and the temperature in the reactor was kept at 80 ° C. for 2 hours with stirring. Thereafter, the temperature inside the reactor was maintained at 60 ° C., tetrabutylammonium acetate was added, and when the yield reached 45%, phosphoric acid was added to stop the reaction. After filtering the reaction solution, unreacted HDI was removed using a thin film evaporator. Viscosity at 25 ° C is 25,000 mPas, isocyanate content is 19.
5% polyisocyanate-II was obtained.

[0043]

[Production Example 3] (Production of active methylene block polyisocyanate) A 4-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen blowing tube was placed in a nitrogen atmosphere to prepare 100 parts of polyisocyanate-I and xylene. 41 parts were charged, diethyl malonate 61 parts, ethyl acetoacetate 25 parts, 28%
A mixture of 0.8 parts of sodium methylate solution was added slowly at room temperature. After the addition was completed, the reaction was continued at 60 ° C for 6 hours. Then, 15 parts of 1-butanol was added and stirred sufficiently. An active methylene-based blocked polyisocyanate having a resin content of 75% and a blocked isocyanate group content (as an isocyanate group) of 9.4% was obtained.

[0044]

Production Examples 4 to 9 (Production of Active Methylene Block Polyisocyanate) With the formulation shown in Table 1, the active methylene block polyisocyanate was obtained in the same manner as in Production Example 1.

[0045]

Example 1 100 parts of the active methylene-based block polyisocyanate obtained in Production Example 3, acrylic polyol (Dainippon Ink's trade name Acrydike A-801, resin content hydroxyl value 100 mgKOH / g, resin content 50%) 252
And 27 parts of 1-butanol were mixed, and 68 parts of a mixed solution of ethyl acetate / toluene / butyl acetate / xylene / propylene glycol monomethyl ether acetate (weight ratio = 30/30/20/15/5) was added as a thinner to the mixture. added. This is heated at 70 ° C. for 1 hour, and then the above thinner is further added to the Ford cup # 4 for 20 seconds / 20.
The viscosity was adjusted to ° C to obtain a thermosetting composition. The resulting thermosetting composition was coated with an air spray gun so that the dry film thickness would be 50 microns, and the curability was evaluated. A part of the thermosetting composition was used for a storage stability test. Table 2 shows the obtained results.

[0046]

Example 2 Instead of heating at 70 ° C. for 1 hour, 100
A thermosetting composition was obtained in the same manner as in Example 1 except that heating was carried out at 30 ° C. for 30 minutes, and the physical properties of the coating film and the storage stability test were performed. Table 2 shows the obtained results.

[0047]

Examples 3 to 13 With the formulations shown in Table 2 or Table 3, a thermosetting composition was obtained in the same manner as in Example 1, and the physical properties of the coating film and the storage stability test were conducted. The obtained results are shown in Table 2 or Table 3.

[0048]

[Comparative Examples 1 and 2] The thermosetting composition having the composition shown in Table 3 was obtained in the same manner as in Example 1 except that the composition was not heated, and the physical properties of the coating film and the storage stability test were conducted. Table 3 shows the obtained results. As shown in Table 3, the storage stability was insufficient.

[0049]

[Table 1]

[0050]

[Table 2]

[0051]

[Table 3]

[0052]

EFFECTS OF THE INVENTION According to the present invention, the low temperature curability and the storage stability are excellent as compared with the conventional non-yellowing one-pack type polyurethane paint mainly composed of polyol and block polyisocyanate. A thermosetting composition is obtained.
The thermosetting composition of the present invention is a top coat paint for automobiles, chipping-resistant paints, electrodeposition paints, paints for automobile parts, paints for repairing automobiles, pre-coated metal for metal products such as home appliances and office equipment, rust prevention. It exhibits excellent performance as steel plates, paints for building materials, paints for plastics, adhesives, adhesion promoters, sealing agents, etc.

Claims (4)

[Claims] 1. A composition containing (A) an active methylene-based blocked polyisocyanate and (B) a polyhydric hydroxy compound in the presence of (C) a monofunctional and / or difunctional active hydrogen-containing compound in a nonvolatile manner. It is obtained by heating in a temperature range of 40 to 150 ° C. in a state of minutes of 10 to 90 wt%,
A thermosetting composition suitable for coating. 2. The thermosetting composition according to claim 1, wherein the (C) monofunctional and / or difunctional active hydrogen-containing compound is an alcohol. 3. A composition containing (A) an active methylene-based blocked polyisocyanate and (B) a polyhydric hydroxy compound, is non-volatile in the presence of (C) a monofunctional and / or difunctional active hydrogen-containing compound. A method for producing a thermosetting composition suitable for coating, which comprises heating in a temperature range of 40 to 150 ° C. in a state of a content of 10 to 90% by weight. 4. The method for producing a thermosetting composition according to claim 3, wherein the (C) monofunctional and / or difunctional active hydrogen-containing compound is an alcohol.