JPH08302280A - Low-temperature-curable one-pack coating material composition - Google Patents

Abstract

PURPOSE: To obtain the subject composition excellent in low-temperature curability and storage stability, comprising a resin having both epoxy and hydroxyl groups, a blocked polyisocyanate, and tertiary and/or quaternary amine-based compound(s) as indispensable components. CONSTITUTION: This composition comprises, as indispensable components, (A) an epoxy resin and/or acrylic resin having both epoxy and hydroxyl groups, (B) a blocked polyisocyanate obtained from a polyisocyanate consisting of an aliphatic and/or alicyclic diisocyanate, and (C) a tertiary and/or quaternary amine-based compound(s). The composition is obtained for example by blending 100 pts.wt. of an epoxy resin solution obtained by dissolving 100 pts.wt. of a disphenol A type epoxy resin (epoxy group concentration: 2.2%; hydroxyl value: 180mgKOH/g) in 150 pts.wt. of Butyl Cellosolve, with 24 pts.wt. of a hexamethylene diisocyanate-based urethane-modified isocyanurate type blocked polyisocyanate, and 0.30 pt.wt. of 1,4-diazabicyclo[2,2,2]octane.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a low temperature curable one-pack coating composition.

[0002]

BACKGROUND ART As a coating composition, an epoxy resin-based coating composition takes advantage of the excellent reactivity and physical properties of an epoxy resin, and is used for precoat metal coatings, can coatings, automobile coatings, heavy-duty anticorrosion coatings for construction. Is widely used as. In many of these cases, a curing agent is further used to enhance the physical properties of the coating film. As its curing agent, amine-based curing agents, polyamidoamine-based curing agents, acid and acid anhydride-based curing agents, block polyisocyanate-based curing agents, dicyanamide-based curing agents, organic hydrazide-based curing agents, polymercaptan-based curing agents, and many others. is there.

Among these curing agents, block polyisocyanate type curing agents which can form a one-component thermosetting coating material are widely used. For example, there are cation electrodeposition in automobile coating, a primer of pre-coated metal and the like. The blocked polyisocyanate-based curing agent reacts with the hydroxyl group of the epoxy resin to form a urethane bond, whereby a tough and flexible coating film physical property can be obtained.

Therefore, in many cases, hydroxyl groups are positively introduced into the epoxy resin. For example, in cationic electrodeposition for automobiles such as Japanese Examined Patent Publication No. 6-99652 and Japanese Examined Patent Publication No. 6-21237, the epoxy group in the bisphenol type epoxy resin is reacted with an amine compound to give a highly reactive first-class compound. Introducing a hydroxyl group. In addition, Japanese Patent Laid-Open No. 2-1031
No. 32, JP-A No. 2-194946, etc., the coating of rust-preventive steel sheets also describes that a bisphenol type epoxy resin having a hydroxyl group is cured with a blocked polyisocyanate.

Further, in JP-A-2-215826, epoxy resin / aromatic block polyisocyanate /
A room-temperature curable coating composition containing a polysulfide / amine curing agent as an essential component has been proposed. On the other hand, as a topcoat paint for automobiles, a technique of crosslinking an acrylic resin having an epoxy group and a hydroxyl group with a block polyisocyanate-based curing agent is proposed in, for example, JP-A-2-145666 and JP-A-5-39454. There is.

These paints are required to have further low temperature curability and excellent storage stability from the viewpoints of energy saving and productivity improvement.

[0007]

SUMMARY OF THE INVENTION In view of the above requirements, the present invention has a low temperature curability and is excellent in storage stability.
It is in the establishment of a liquid thermosetting coating composition.

[0008]

Means for Solving the Problems As a result of intensive investigations by the present inventors, the composition has excellent storage stability which has low-temperature curability and is unthinkable in a commonly known room-temperature curable coating composition. The present invention was accomplished by discovering a coating composition having That is, the present invention is an epoxy resin having both an epoxy group and a hydroxyl group and /
Alternatively, a coating composition containing a blocked polyisocyanate obtained from an isocyanurate type polyisocyanate of an acrylic resin, an aliphatic and / or an alicyclic diisocyanate as an essential component, a tertiary and / or quaternary amine compound. Is the main point.

The present invention will be further described in detail. Examples of the resin having both an epoxy group and a hydroxyl group used in the present invention include novolac type, β-methylepichloro type, cyclic oxirane type, glycidyl ether type, glycol ether type,
Epoxy resins of aliphatic unsaturated compounds, epoxidized fatty acid ester type, polyvalent carboxylic acid ester type, aminoglycidyl type, halogenated type, resorcin type and the like can be mentioned, for example, polyphenol compounds in the presence of alikari. There are epoxy ethers of polyphenolic compounds produced by reacting with epichlorohydrin. Examples of the polyphenol compound include:
2,2-bis (4-hydroxyphenyl) propane,
4,4'-dihydroxybenzophenone, 1,1-bis (4-hydroxyphenyl) ethane, 1,1-bis (4
-Hydroxyphenyl) isobutane, 2,2-bis (4
-Hydroxy-tert-butylphenyl) propane,
Bis (2-hydroxynaphthyl) methane, 1,5-dihydroxynaphthalene, bis (2,4-dihydroxyphenyl) methane, 1,1,2,2-tetra (4-hydroxyphenyl) ethane, 4,4′-dihydroxy Examples include diphenyl ether, 4,4'-dihydroxydiphenyl sulfone, phenol novolac, and cresol novolac.

When the epoxy group formula amount is 43, the epoxy group concentration per part by weight of the resin shown below is 0.1-2.
0%, preferably 0.5-10, more preferably 0.5
~ 5%.

[0011]

[Equation 1]

A preferred structure is shown in formula (1).

[0013]

Embedded image

The polyphenol epoxy ether compound may be partially reacted with a polyol, a polyether polyol, a polyester polyol, a polyamidoamine, a polycarboxylic acid, a polyisocyanate or the like, and further, a caprolactone or an acrylic monomer may be polymerized. Good. An acrylic resin having both an epoxy group and a hydroxyl group can also be used. Monomers for synthesizing this acrylic resin include (1) epoxy group-containing vinyl monomers such as glycidyl acrylate, glycidyl methacrylate, glycidyl methacrylamide, and allyl glycidyl (2) 2-hydroxyethyl acrylate, 2-hydroxyethyl meta Hydroxyalkyl ester having 1 to 8 carbon atoms such as acrylate, hydroxypropyl acrylate and hydroxypropyl methacrylate (3) Methyl acrylate, methyl methacrylate,
Ethyl acrylate, ethyl methacrylate, n-butyl acrylate, n-butyl methacrylate, i-
Butyl acrylate, i-butyl methyl acrylate, t
Acrylic acid such as ert-butyl acrylate, tert-butyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, lauryl acrylate, lauryl methacrylate, stearyl acrylate, stearyl methacrylate, decyl acrylate Or an alkyl or cycloalkyl ester of methacrylic acid having 1 to 24 carbon atoms (4) styrene, vinyltoluene, vinyl propionate, α-methylstyrene, vinyl acetate, acrylonitrile, methacrylonitrile, vinyl propionate, vinyl pivalate, etc. Copolymerization with a monomer selected from (3) and (4), which has a vinyl monomer and requires (1) and (2) above. There is.

The number average molecular weight of this copolymer is 500 to 5
It is 50,000, preferably 1,000 to 20,000. Epoxy group concentration per 1 part by weight of resin is 0.1% to
It is 10%, preferably 0.5% to 10%.
If it is less than 0.1%, the low-temperature crosslinkability becomes insufficient and 10
If it exceeds%, the storage stability of the coating composition deteriorates. Although a part of the epoxy group may be modified with an amine compound or the like,
It is necessary to have epoxy groups. The amine compound may be an aliphatic, alicyclic or aromatic-aliphatic primary compound.
There are class, secondary or tertiary amine compounds, and specific examples include the following compounds. (1) Methylamine, diethanolamine, di-n- or iso-propylamine, monoethanolamine, n
-Or iso-propanolamine or other primary amine compound (2) Diethylamine, diethanolamine, di-n- or iso-propanolamine, N-methylethanolamine, N-ethylethanolamine or other secondary amine compound (3) Polyamine compounds such as ethylenediamine, diethylenetriamine, hydroxyethylaminoethylamine, ethylaminoethylamine, methylaminopropylamine, dimethylaminoethylamine, dimethylaminopropylamine, etc. Among these, alkanolamine compounds having a hydroxyl group are preferable.

On the other hand, the hydroxyl group concentration of these resins is 20 to 5
00 mg KOH / g resin, preferably 50-3200 m
gKOH / g resin. If it is less than 20 mgKOH / g resin, the cross-linking of the coating film is not sufficient and 500 mgKOH
If it exceeds 0.1 g / g resin, the toughness of the coating film decreases, and the water resistance after baking the coating film decreases, which is not preferable. The polyisocyanate for obtaining the blocked polyisocyanate used in the present invention is the aliphatic / alicyclic diisocyanate described below. The aliphatic diisocyanate preferably has 4 to 30 carbon atoms, and the alicyclic diisocyanate preferably has 8 to 30 carbon atoms. For example, tetramethylene-1,4-diisocyanate, pentamethylene-1. , 5-diisocyanate, hexamethylene diisocyanate, 2,2,4 (or 2,4,4) -trimethyl-1,6-hexamethylene diisocyanate, lysine diisocyanate, isophorone diisocyanate,
1,3-bis (isocyanatomethyl) -cyclohexane, 4,4′-dicyclohexylmethane diisocyanate, xylylene diisocyanate, tetramethyl xylene diisocyanate and the like can be mentioned. Hexamethylene diisocyanate (hereinafter referred to as HMDI) and isophorone diisocyanate (hereinafter referred to as IPDI) are preferable from the viewpoint of industrial availability. These may be used alone or in combination of two or more.

Polyisocyanates obtained from these diisocyanates include urethane-modified polyisocyanates obtained by reacting with an active hydrogen compound, biuret-type polyisocyanates, isocyanurate-type polyisocyanates obtained by polymerization of isocyanate groups, and the like. These are polyisocyanates from which diisocyanate has been removed, and it is preferable that they are substantially free of diisocyanate.

The urethane-modified polyisocyanate can be obtained by reacting the above-mentioned diisocyanate with a compound having two or more active hydrogens in the molecule. Compounds having such active hydrogen include low molecular weight active hydrogen compounds and high molecular weight active hydrogen compounds. The low molecular weight active hydrogen compound is a compound having two or more active hydrogens in the molecule, and examples of the bifunctional or higher alcohol include ethylene glycol, 1,2- or 1,3-bromopyrene glycol, 1, 3- or 1,4- or 2,3-butylene glycol, 1,6-hexanediol, neopentyl glycol, 2-methyl-2,4-pentanediol, 2,2,4-trimethyl-1,3-pentane Examples include diol, trimethylolpropane, glycerin, and pentaerythritol.

Examples of the high molecular weight active hydrogen compound include aliphatic hydrocarbon polyols, polyether polyols, polyester polyols and epoxy resins. Specific examples of the aliphatic hydrocarbon polyols include, for example, end-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. Or a polyester polyol resin obtained by a condensation reaction of a mixture and a polyhydric alcohol selected from the group of ethylene glycol, propylene glycol, diethylene glycol, neopentyl glycol, trimethylolpropane, glycerin, etc., alone or in a mixture, and, for example, ε- Examples thereof include polycaprolactones obtained by ring-opening polymerization of caprolactone using a polyhydric alcohol such as trimethylolpropane.

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 and resorcin type epoxy resins.

A catalyst is usually used in the isocyanurate-forming reaction for obtaining the isocyanurate type polyisocyanate. Generally, the catalyst used here preferably has a basic property, for example, tetramethylammonium,
Tetraalkylammonium hydroxides such as tetraethylammonium and organic weak acid salts such as acetic acid and capric acid, for example, hydroxyalkylammonium hydroxides such as trimethylhydroxypropylammonium, trimethylhydroxyethylammonium, triethylhydroxypropylammonium and triethylhydroxyethylammonium. Or, for example, acetic acid, an organic weak acid salt such as capric acid, an alkylcarboxylic acid such as tin, zinc, an alkyl metal salt such as lead, for example, a metal alcoholate such as sodium or potassium, for example, an aminosilyl group-containing compound such as hexamethyldisilazane,
Mannich bases, tertiary amines and epoxy compounds are used in combination, for example, phosphorus compounds such as tributylphosphine.

The catalyst concentration is usually selected from the range of 10 ppm to 1.0% based on the isocyanate compound.
The reaction may or may not use a solvent. If a solvent is used, it should be inert to the isocyanate groups. The reaction temperature is generally 20 to 160 ° C, preferably 40 to 130 ° C. The reaction end point varies depending on the polyhydric alcohol used, but the yield is about 20% or more.

When the reaction reaches the desired yield, the catalyst is deactivated by, for example, sulfonic acid, phosphoric acid or the like to stop the reaction. Unreacted diisocyanate and solvent can be removed to obtain an isocyanurate type polyisocyanate having an isocyanurate structure. Further, the urethane modification may be carried out by carrying out a urethane formation reaction of a low molecular weight active hydrogen compound and diisocyanate prior to or simultaneously with the isocyanurate formation reaction. The low molecular weight active hydrogen compound is a monoalcohol other than the above-mentioned low molecular weight active hydrogen compound and high molecular weight active compound, preferably an alcohol having a valence of 3 or more, such as methanol, ethanol, butanol, heptanol, and 2-ethyl having 1 to 13 carbon atoms. Hexanol, nonanol, decanol, undecanol, tridecanol and the like.

Among the above polyisocyanates, isocyanurate type polyisocyanates are preferable from the viewpoint of heat resistance. The isocyanate group of the polyisocyanate thus obtained is reacted with a blocking agent to obtain a blocked polyisocyanate. Examples of the blocking agent include alkylphenol type, phenol type, active methylene, mercaptan type, acid amide type, acid imide type,
Examples include imidazole-based, urea-based, oxime-based, amine-based, imide-based, and pyrazole-based compounds. Examples of more specific blocking agents are shown below. (1) Alkylphenol type; mono- and dialkylphenols having an alkyl group having 4 or more carbon atoms as a substituent, such as n-propylphenol, i
-Propylphenol, n-butylphenol, sec
-Butylphenol, t-butylphenol, n-hexylphenol, 2-ethylhexylphenol, n-
Monoalkylphenols such as octylphenol and n-nonylphenol, di-n-propylphenol, diisopropylphenol, isopropylcresol, di-n-butylphenol, di-t-butylphenol,
Di-sec-butylphenol, di-n-octylphenol, di-2-ethylhexylphenol, di-n-
Dialkylphenols such as nonylphenol (2) Phenol type; phenol, cresol, ethylphenol, styrenated phenol, hydroxybenzoic acid ester, etc. (3) Active methylene type; dimethyl malonate, diethyl malonate, methyl acetoacetate, ethyl acetoacetate , Acetylacetone, etc. (4) Mercaptan type; butyl mercaptan, dodecyl mercaptan, etc. (5) Acid amide type; acetanilide, acetic acid amide, ε-
Caprolactam, δ-valerolactam, γ-butyrolactam, etc. (6) Acid imide type; succinimide, maleic acid imide, etc. (7) Imidazole type; imidazole, 2-methylimidazole, etc. (8) Urea type; urea, thiourea, Ethylene urea, etc. (9) Oximes; formaldoxime, acetoaldoxime, acetoxime, methylethylketoxime, cyclohexanone oxime, etc. (10) Amines; diphenylamine, aniline, carbazole, di-n-propylamine, diisopropylamine, isopropylethylamine Etc. (11) Imine-based; ethyleneimine, polyethyleneimine, etc. (12) Bisulfite; sodium bisulfite, etc. (13) Pyrazole-based; pyrazole, 3-methylpyrazole, 3,5-dimethylpyrazole, and the like.

Alkylphenol-based, oxime-based, acid amide-based, and active methylene-based are preferable, and particularly nonylphenol, acetoxime, methylethylketoxime, ε.
-Caprolactam, ethyl acetoacetate, and diethyl malonate are preferable, and two or more kinds may be mixed. The mixing ratio of the block polyisocyanate and the epoxy group- and hydroxyl group-containing resin is such that the equivalent ratio of the effective isocyanate group and the hydroxyl group of the block polyisocyanate is 1 / 0.1 / 1 /.
10, preferably 1 / 0.25 to 1/4.

Examples of the tertiary amine compound used in the present invention include (1) trioctylamine and N-methyl-
Dioctylamine, tri (2-ethylhexyl) amine, N, N-dibutyl-2-ethylhexylamine,
N, N-diisopropylethylamine, 3-diethylamino-1-propanol, N-isobutyldiethanolamine, N, N, N ', N'-tetramethyl-1,2-
Diaminoethane, N, N, N ', N',-tetramethyl-1,3-diaminopropane, N, N, N ', N'-tetramethylhexamethylenediamine, N, N, N',
N'-tetramethyldiaminomethane, N, N, N'N '
An aliphatic tertiary such as pentamethyldiethylenetriamine
Morpholine compounds such as secondary amine compounds, (2) N-methylmorpholine and N-ethylmorpholine, (3) N-methylpiperidine, N-ethylpiperidine, N-methyl-
3-piperidinemethanol, N-formylpihelidine,
N-formyl-4-pipecoline, N-methyl-3-hydroxybiperidine, N-ethyl-3-hydroxypiperidine, N-methyl-4-hydroxypiperidine, 4-piperidinopiperidine, dipiperidinomethane, 1,3-Di- (4-piperidyl) propane and other piperidine compounds, (4) N-methyl-4-piperidone, N-benzylpiperidone and other piperidone compounds, (5) N, N-dimethylbenzylamine , N, N-dibenzylethanolamine, tribenzylamine, aromatic ring-containing tertiary amine compounds such as 1-benzyl-4-hydroxypiperidine, (6) N-methylpyrrolidine, N-ethylpyrrolidine, N-butyl Pyrrolidine-based compounds such as pyrrolidine, N-methyl-2-hydroxyethylpyrrolidine and N-formylpyrrolidine, (7) 3, Pyridazine compounds such as 6-dichloropyridazine, (8) pyrimidine, 2-methylpyrimidine, pyrimidine compounds such as 1,2-dimethyl-1,4,5,6-tetrahydropyrimidine, (9) N
-Hydroxyethoxyethylpiperazine, N-methylpiperazine, 1,4-dimethylpiperazine, 1,4-diethylpiperazine, 1-methyl-4-dimethylaminoethylpiperazine, 1,4-bis (2-hydroxypropyl) 2-methyl Piperazine, N-methyl-N'-hydroxyethylpiperazine, N-carbetoxypiperazine,
N-formylpiperazine, 1- (o-chlorophenyl)
Piperazine, 1- (m-chlorophenyl) piperazine,
1- (p-chlorophenyl) piperazine, 1- (2-pyridyl) piperazine, 1-cyclopentylpiperazine, 1- (3-chloropropyl) -4-methylpiperazine, 1- (3-chlorophenyl) -4- (3- Chloropropyl) piperazine, N- (2-pyridyl) piperazine, N-methylhomopiperazine and other piperazine compounds, (10) pyrazine, 2-methylpyrazine, 2,5-dimethylpyrazine and other pyrazine compounds, (11) pyridine And a monoalkyl or dialkyl such as methyl, ethyl, propyl, butyl or isobutyl and a pyridine compound such as alkanol addition pyridine such as methanol, ethanol, propanediol or propanetriol, (12) imidazole, 2-methylimidazole, 2-ethyl -4
-Imidazole compounds such as methylimidazole, (1
3) 1,5-diazabicyclo (4,3,0) nonene-5,
1,8-diazabicyclo (5,4,0) undecene-
7,6-Dibutylamino-1,8-diazabicyclo (5,4,0) undecene-7,1,4-diazabicyclo (2,2,2) octane, 2-methyl-1,4-diazabicyclo (2,2) , 2) Cyclic amine compounds such as octane, (14) 2,4,6-tri (dimethylaminomethyl) phenol, dimethylaminomethylphenol, aminophenol compounds such as tris (dimethylaminophenol), (15) N , N-dimethylcyclohexylamine, amine compounds having alicyclic groups such as N-methyldicyclohexylamine, and (16) having triazine groups such as N, N ′, N ″ -tris (dimethylaminopropyl) hexahydro-s-triazine Amine compounds, etc. These amine compounds may be completely or partially neutralized with an acid, etc. Has 1 to 17 carbon atoms
Examples thereof include organic carboxylic acids such as acetic acid, octylic acid, oleic acid and capric acid, and organic sulfonic acids such as p-toluenesulfonic acid. Preferred tertiary amine compounds are amine compounds such as the above (13) (14) (15) (16).

Examples of the quaternary amine compound used in the present invention include (1) tetraalkylammonium hydroxides such as tetramethylammonium and tetraethylammonium, and organic weak acid salts such as acetic acid and capric acid, such as hydrochloric acid. Inorganic acid salts, (2) hydroxyalkylammonium hydroxides such as trimethylhydroxypropylammonium, trimethylhydroxyethylammonium, triethylhydroxypropylammonium and triethylhydroxyethylammonium, and weak organic acid salts such as acetic acid and capric acid.

The amount of the tertiary and quaternary amine compounds added is 0.05 to 10% by weight based on the total weight of the resin having both the epoxy group and the hydroxyl group and the block polyisocyanate. Preferably 0.2-2
% By weight. If it is less than 0.05% by weight, the coating film will be insufficiently cured, and if it exceeds 10% by weight, the storage stability of the coating composition will be deteriorated.

In addition to the resin having both the epoxy group and the hydroxyl group, the block polyisocyanate, the tertiary and quaternary amine compounds, some materials are used in combination according to the application. As the solvent, for example, as an organic solvent, for example, xylene, an aromatic hydrocarbon solvent such as toluene, ethyl acetate, an ester solvent such as butyl acetate,
Acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, isophorone and other ketone solvents, methanol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, butanol and other alcohol solvents, ethylene glycol, cellosolve, butyl cellosolve, cellosolve acetate, propylene glycol monomethyl Examples include ether solvents such as ether acetate. These organic solvents are 1
They may be used alone or in combination of two or more.

Examples of the pigment include organic pigments such as quinacridone compounds such as quinacridone, azo compounds such as pigment red, phthalocyanine compounds such as phthalocyanine blue and phthalocyanine green,
Titanium oxide, barium sulfate, calcium carbonate, barita,
There are inorganic pigments such as clay and fumed silica, carbon-based pigments such as carbon black, scaly metallic pigments such as aluminum, mica-like iron oxide and stainless steel, and rust-preventive pigments such as red iron oxide and strontium chromate.

In addition to the above, it is also possible to use additives such as an ultraviolet absorber, a surface conditioner and a pigment dispersant.
The coating composition of the present invention preferably does not use a resin having a carboxylic acid group, but when used, the acid value of the resin is 20 mgKOH / g or less, preferably 10 mgKOH
OH / g or less. If the acid value exceeds 20 mgKOH / g, the storage stability of the coating composition deteriorates, which is not preferable.

The thus-prepared coating composition is roll-coated, curtain-flow coated, spray-coated, etc., and is used as a primer or overcoat on a metal such as a steel plate or a surface-treated steel plate or a material such as plastic, and also contains a rust-proof steel plate. It is useful for painting pre-coated metal and automobiles.

[0034]

The present invention will be described in more detail based on the following examples, but the invention is not intended to be limited to the following examples. (Gel Fraction) It is the ratio of the undissolved part weight of the cured coating film when immersed in butyl cellosolve at 50 ° C. for 8 hours to that before immersion, and less than 90% is represented by x, and 90% or more is represented by o. (Paint stability) The paint was stored at 50 ° C for 1 week, and its fluidity was observed. A large increase in viscosity or no fluidity was marked with X, and a slight increase in viscosity and no increase in viscosity were marked with O.

[0035]

[Production Example-1] Bisphenol A type epoxy resin having both epoxy group and hydroxyl group (Asahi Ciba brand name AER
6007, epoxy group concentration 2.2%, hydroxyl value 180m
100 parts of gKOH / g) was dissolved in 150 parts of futyl cellosolve to obtain an epoxy resin solution (A-1).

[0036]

[Production Example-2] Bisphenol A type epoxy resin having both an epoxy group and a hydroxyl group (Asahi Ciba brand name AER
6007) 100 parts of it was dissolved in 158 parts of futyl cellosolve, the temperature was raised to 90 ° C., and then diethanolamine 5.1 was added.
Parts were added dropwise over 30 minutes so that the reaction temperature was kept at 90 ° C. After completion of dropping, the reaction temperature was kept at 100 ° C. for 1 hour.
A resin (A-2, hydroxyl value per resin: 240 mgKOH / g) containing 40% of the resin content and containing no epoxy group was obtained.

[0037]

[Production Example-3] Styrene 30 in 100 parts of xylene
Parts, n-butyl methacrylate 20 parts, 2-ethylhexyl acrylate 10 parts, glycidyl methacrylate 3
0 part, 2-hydroxyethyl acrylate 10 parts of the monomer were reacted to give a resin content of 50% and a hydroxyl value of 48 mg KO.
H / g resin, acrylic resin containing both epoxy groups and hydroxyl groups with an epoxy group concentration of 9.1% per resin (A-
3) was obtained.

[0038]

[Production Example-4] 30 parts of styrene, 40 parts of n-butyl methacrylate, 10 parts of 2-ethylhexyl acrylate in an organic solvent of 85 parts of xylene and 15 parts of n-butanol,
Acrylic acid (10 parts) and 2-hydroxyethyl acrylate (10 parts) were reacted to give a resin solid content of 50%, a hydroxyl value of 48 mgKOH / g resin, and an acid value of 78 mgKOH /.
An acid value-containing acrylic resin (A-4) of g resin was obtained.

[0039]

Example 1 Resin solution (A-1) obtained in Production Example-1
100 parts, hexamethylene diisocyanate urethane-modified isocyanurate type block polyisocyanate 2
4 parts (Duranate MF-B80, trade name of Asahi Kasei Corporation
M) and 0.30 part of a tertiary amine compound 1,4-diazabicyclo [2.2.2] octane (trade name “DABCO” of Sankyo Air Products) were mixed and applied on a tin plate with an applicator. The tin plate coated in an oven maintained at 120 ° C was baked for 30 minutes. The baked coating film was peeled off and the gel fraction was measured. The gel fraction was ◯.

Separately, the above coating liquid is sealed at 50 ° C.
The coating was allowed to stand for 1 week in the oven held at, and the flow state of the paint was observed. As a result, the paint did not gel and maintained a good fluid state. The results are shown in Table 1.

[0041]

[Examples 2 to 7] The same procedure as in Example 1 was carried out except that the formulation shown in Table 1 was used.

[0042]

Examples 8 to 10 The same procedure as in Example 1 was carried out except that the acrylic resin (A-3) obtained in Production Example-2 was used and the composition shown in Table 1 was used. The results are shown in Table 1.

[0043]

[Comparative Examples 1 to 4] The formulations are shown in Table 1, and the other conditions were the same as in Example-1. Table 2 shows the results.

[0044]

[Table 1]

[0045]

[Table 2]

[0046]

EFFECTS OF THE INVENTION According to the present invention, a coating composition which is excellent in both low-temperature curing property and storage stability, improves productivity in the coating process, saves energy, and is applied to a material having no heat resistance and is very useful. Can provide things.

Claims (1)

[Claims] 1. A block polyisocyanate obtained from a polyisocyanate comprising an epoxy resin and / or an acrylic resin having both an epoxy group and a hydroxyl group, an aliphatic and / or alicyclic diisocyanate, a tertiary and / or quaternary amine compound. A low temperature curable one-pack coating composition containing as an essential component.