JP2626767B2 - Low temperature curable coating composition - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composition for a low-temperature-curable polyurethane-based coating material, and more particularly, to a composition which is completely cured by baking at a low temperature, and which is so-called abbreviated during baking. The present invention relates to a one-pack type polyurethane coating composition which gives a cured coating film which is smooth and excellent in chipping resistance without causing foaming.

2. Description of the Related Art For example, in automotive coatings, there is a strong demand that coating films should not be damaged by impact, that is, have excellent chipping resistance.

Conventionally, as such a chipping-resistant paint, a one-pack type polyurethane-based paint is often used, but according to the conventionally known paint, in order to cure, usually about 140 to 180 ° C. Requires about 20 to 40 minutes of heating and baking, which results in high energy costs, and also has the problem that the object to be coated is limited to metal.

Therefore, the development of a one-component polyurethane-based paint that cures at a relatively low temperature, for example, at a temperature lower than 130 ° C., has been desired. Conventionally, for the purpose of lowering the curing temperature, a block polyisocyanate has been developed. Various studies on low-temperature dissociation have been made. For example, low temperature dissociation of a blocked polyisocyanate using a blocking agent having a relatively low dissociation temperature such as ethyl acetoacetate or ethyl malonate, or a blocked polyisocyanate using various dissociation catalysts. Is being studied.

However, in general, when a coating composition is prepared using such a low-temperature dissociable, blocked polyisocyanate as a resin component, the curing temperature is low, but on the other hand, storage stability is significantly deteriorated, and Since the performance of the coating film also deteriorates, new problems such as insufficient chipping resistance cannot be obtained.

On the other hand, conventionally, as a chipping-resistant one-pack type polyurethane coating, for example, JP-A-61-218664 discloses a polyamine polyether which is an alkylene oxide adduct of a polyalkylene polyamine, and an oxime or a blocking agent. A composition comprising a blocked polyisocyanate using a lactam has been proposed as a one-pack type polyurethane coating composition having excellent chipping resistance. According to such a paint, although the chipping resistance has been improved to some extent, however, when this is formed into a film and baked, the paint has extremely poor bubble bleeding properties. Can not get. In particular, when the film thickness is set to 100 μm or more, this side is serious. Further, at a baking temperature of 120 ° C. or lower, the coating film is insufficiently cured. To improve the curability of the coating,
It is possible to mix catalysts such as secondary amines, metal salts, and organometallic compounds in the coating composition, but in order to cure at a baking temperature of 120 ° C or less, it is necessary to mix a large amount of the catalyst. Thereafter, the coating film easily deteriorates due to the remaining catalyst, and there is a problem that the durability is practically inferior.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention The present inventors have conducted intensive studies to solve the above-mentioned problems in the conventional chipping-resistant polyurethane coating composition, and as a result, a given aromatic polyisocyanate or polyol About 10 to 20 minutes at a low temperature of about 90 to 110 ° C. by combining a blocked aromatic polyisocyanate obtained by blocking a polyurethane prepolymer obtained by the reaction with an oxime and a polyamine polyether polyester. To obtain a coating composition which is hardened by heating at the same time, and which can obtain a cured coating film which is smooth, has excellent chipping resistance, and has excellent storage stability. It has been found that the present invention can be performed, and has led to the present invention.

Means for Solving the Problems The coating composition according to the present invention comprises: (a) an aromatic polyisocyanate or an aromatic polyisocyanate having a terminal isocyanate group, which is obtained by blocking a polyurethane prepolymer with oximes. And (b) a polyamine polyether polyester which is a condensate of an organic carboxylic acid with a polyamine polyether which is an adduct of ethylene oxide or tetrahydrofuran to the polyamine.

The blocked polyisocyanate used in the present invention is an addition reaction with an aromatic polyisocyanate or an isocyanate group of a polyurethane prepolymer of an aromatic polyisocyanate having a terminal isocyanate group. Compound that easily dissociates by heating and / or catalysis to form a bond that regenerates an aromatic polyisocyanate or a polyurethane prepolymer having an isocyanate group (hereinafter referred to as a blocking agent). And an aromatic polyisocyanate or a polyurethane prepolymer. In the present invention, a blocking agent obtained by using an oxime as a blocking agent is used. Such blocked polyisocyanates are already known and are disclosed, for example, in
No. 60-203685.

In the present invention, examples of the aromatic polyisocyanate or the aromatic polyisocyanate for the blocked polyisocyanate include 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, ,Four'
-Diphenyl diisocyanate, 4,4'-diphenyl methane diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-toluidine diisocyanate, dianisidine di Isocyanate,
4,4'-diphenyl ether diisocyanate, 4,4 ',
4 ″ -triphenylmethane triisocyanate, 1,3,5-
Examples thereof include triisocyanatobenzene and 2,4,6-triisocyanatotoluene. Also, 4,4'-
The diphenylmethane diisocyanate may be a so-called crude product, or a so-called liquid MDI that has been subjected to various modifications such as carbodiimide modification. Further, the above-mentioned aromatic polyisocyanates can be used as a mixture.

In the present invention, by using the above-mentioned aromatic polyisocyanate, it is possible to obtain a one-pack type polyurethane-based coating composition having particularly excellent low-temperature curability.

The polyurethane prepolymer used in the present invention is
As described above, the polyisocyanate and the polyol are preferably such that the isocyanate group of the polyisocyanate is in excess of the hydroxyl group of the polyol, preferably in an equivalent ratio of the isocyanate group to the hydroxyl group of about 1.2 to 5.0. To give a reaction.

As the polyol, those having at least two active hydrogens in the molecule and having a molecular weight in the range of 62 to 100,000 are preferably used.

Such polyols include, for example, polyester polyols, polyether polyols, polyether ester polyols, polyester amide polyols, acrylic polyols, polyurethane polyols, polycarbonate polyols, epoxy polyols, epoxy-modified polyols, polyhydroxyalkanes, oil-modified polyols, castor oil and And mixtures thereof.

The production of a polyurethane prepolymer by the reaction of such a polyol with a polyisocyanate is well known, and is usually carried out in a solvent or in the absence of a solvent, usually from about 0 to 200.
The reaction may be performed at a temperature of ° C. For this reaction, a conventionally known catalyst such as a tertiary amine, a metal salt, or an organometallic compound may be used, if necessary.

Among the polyols described above, as the polyester polyol, for example, a reaction product of a polyhydric alcohol and a polybasic acid is preferably used.

Here, as the polyhydric alcohol, for example, ethylene glycol, propylene glycol, butylene glycol, hexylene glycol, neopentyl glycol,
Cyclohexane dimethanol, diethylene glycol,
Triethylene glycol, polyoxyethylene glycol, dipropylene glycol, polyoxypropylene glycol, polyoxybutylene glycol, glycerin, trimethylolpropane, pentaerythritol,
Sorbitan and the like can be mentioned.

Examples of polybasic acids include, for example, succinic acid, adipic acid, azelaic acid, sebacic acid, phthalic acid, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, maleic acid, fumaric acid, and acid anhydrides thereof. Objects and the like. Further, a polyester polyol obtained by subjecting a lactone such as caprolactone or methylcaprolactone to ring-opening polymerization with glycol or the like is also used.

Polyether polyols are epoxide compounds, for example, ethylene oxide, propylene oxide, α-olefin oxide or alkylene oxide such as butylene oxide, aromatic vinyl compound oxide such as styrene oxide, epichlorohydrin, phenyl glycidyl ether, allyl glycidyl ether and the like. A glycidyl compound or the like, or a cycloalkylene ether such as tetrahydrofuran, for example, is subjected to addition polymerization using an initiator compound having a reactive hydrogen atom in the presence of a catalyst such as boron trifluoride. I can get it. The above-mentioned epoxide compound or tetrahydrofuran may be subjected to addition polymerization alone or as a mixture, or may be alternately addition-polymerized.

Examples of the initiator compound having a reactive hydrogen atom include:
Water, and also the above-mentioned polyols, for example, ethylene glycol, propylene glycol, glycerin, trimethylolpropane, pentaerythritol, sorbitol, amino alcohols such as ethanolamine, and polyamines such as ethylenediamine.

Examples of the polyetherester polyol can be obtained by using the above-mentioned polyetherpolyol as a raw material, and reacting it with a polybasic acid to perform esterification. Further, it can also be obtained by a ring-opening copolymerization reaction between the above-mentioned epoxide compound or tetrahydrofuran and an acid anhydride. Such a polyetherester polyol has both polyether and polyester segments in the molecule.

Examples of polyester amide polyols, for example, when the polyether polyol is reacted with a polybasic acid and esterified, for example, ethylenediamine, propylenediamine, hexamethylenediamine, xylylenediamine, hydrogenated xylylenediamine, ethanol It can be obtained by using a compound having an amine group such as an amine or propanolamine in combination.

Acrylic polyol is generally a copolymer obtained by copolymerizing a polymerizable monomer having one or more hydroxyl groups in a molecule and another monomer copolymerizable therewith. Say.

Here, as the polymerizable monomer having a hydroxyl group, for example, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, trimethylolpropane acrylate monoester, their corresponding methacrylic acid derivatives, polyhydroxy Examples thereof include alkyl maleate and fumarate.

Further, as a monomer copolymerizable with such a monomer, for example, acrylic acid, its methyl, ethyl, propyl, butyl, acrylate such as 2-ethylhexyl ester, methacrylic acid, its methyl, ethyl , Propyl, butyl, methacrylic acid esters such as 2-ethylhexyl ester, maleic acid, fumaric acid, itaconic acid and the above-mentioned alkyl esters, styrene, α-methylstyrene, vinyl acetate, acrylonitrile, methacrylonitrile, etc. Vinyl monomers can be mentioned.

Examples of the polyurethane polyol include a reaction product of a polyol and a polyisocyanate and having a hydroxyl group at a molecular terminal.

Here, as the polyol, for example, ethylene glycol, propylene glycol, butylene glycol,
Hexylene glycol, neopentyl glycol, cyclohexane dimethanol, diethylene glycol, triethylene glycol, polyoxyethylene glycol,
Examples thereof include dipropylene glycol, polyoxypropylene glycol, polyoxybutylene glycol, glycerin, trimethylolpropane, pentaerythritol, and sorbitol. Besides these, polymer polyols such as the polyester polyols, polyether polyols, polyester ether polyols, polyesteramide polyols and the like described above are also used.

As the polyisocyanate, as described above,
For example, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 4,4-diphenyl diisocyanate, 4,4-diphenyl methane diisocyanate, 2,4
-Tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-toluidine diisocyanate, dianisidine diisocyanate, 4,4-diphenyl ether diisocyanate, 4,4 ', 4 "- Aromatic polyisocyanates such as triphenyl methane triisocyanate, 1,3,5-triisocyanatobenzene, 2,4,6-triisocyanatotoluene, for example, trimethylene diisocyanate, tetramethylene diisocyanate, Hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate,
Aliphatic polyisocyanates such as 2,4,4- or 2,2,4-trimethylhexamethylene diisocyanate, dodecamethylene diisocyanate, and 2,6-diisocyanatomethyl caproate can be mentioned.

Further, for example, ω, ω′-diisocyanate-1,3-
Dimethylbenzene, ω, ω'-diisocyanate-1,4
Dimethylbenzene, ω, ω'-diisocyanate-1,
Aromatic aliphatic polyisocyanates such as 4-diethylbenzene, 1,3-tetramethylxylylene diisocyanate, 1,4-tetramethyl xylylene diisocyanate, for example, 1,3-cyclopentane diisocyanate, 1,4- Cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, 3-isocyanatomethyl-3,5,5-
Trimethylcyclohexyl isocyanate, 4,4'-methylenebis (cyclohexyl isocyanate), methyl-2.4-cyclohexanediisocyanate, methyl-2.6
Alicyclic polyisocyanates such as -cyclohexane diisocyanate, 1,4-bis (isocyanatomethyl) cyclohexane, 1,3-bis (isocyanatomethyl) cyclohexane, or dimers of the above-mentioned diisocyanates; Examples thereof include polymerized polyisocyanates such as trimers and polymethylene polyphenylene polyisocyanates.

Further, some of the above polyols such as ethylenediamine, propylenediamine, hexamethylenediamine, xylylenediamine, bisaminomethylcyclohexane, 3-aminomethyl-3,5,5-trimethylcyclohexylamine, ethanolamine, propanolamine, etc. A reaction product reacted in place of the amino compound is also used as the polyurethane polyol.

Preferred specific examples of the epoxy polyol include a condensation-type epoxy resin obtained by reacting a polyphenol compound or a hydride of the nucleus thereof with epichlorohydrin. An epoxy ester resin obtained by reacting with a resin and a modified epoxy resin obtained by reacting with an alkanolamine are also used.

Examples of the polyhydroxylalkane include, for example, a homopolymer of vinyl acetate and a saponified product of a copolymer of vinyl acetate and another ethylenically unsaturated monomer copolymerizable therewith,
Polybutadiene polyol and the like can be mentioned.

Above, as the polyol, a compound having a relatively high molecular weight or a polymer has been mentioned as an example.However, in the present invention, the polyol has a molecular weight of 62 to about 40.
Compounds having a relatively low molecular weight of up to 0 can be used alone or as a mixture. Further, a mixture of a compound or a polymer having a relatively high molecular weight and the above-mentioned compound having a relatively low molecular weight can also be used. Such relatively low molecular weight polyols, for example, ethylene glycol, propylene glycol, butylene glycol, hexylene glycol, neopentyl glycol, cyclohexane dimethanol, diethylene glycol, triethylene glycol, dipropylene glycol, glycerin, trimethylolpropane, Pentaerythritol and the like can be mentioned.

The coating composition according to the present invention contains a blocked polyisocyanate obtained by blocking the aromatic polyisocyanate or the polyurethane prepolymer of the aromatic polyisocyanate having a terminal isocyanate group with oximes. Here, as the oximes, for example, formaldoxime, acetoaldoxime, acetoxime, methyl ethyl ketoxime, methyl isopropyl ketoxime, methyl butyl ketoxime, diethyl ketoxime, diacetyl monooxime, cyclohexanone oxime, benzophenone oxime and the like can be mentioned. be able to.
In the present invention, among these, acetoxime, methyl ethyl ketoxime, methyl isobutyl ketoxime and cyclohexanone oxime are particularly preferably used. These blocking agents may be used alone or in combination of two or more.

Various blocking agents other than the above oxime-based blocking agents are known, and even if other blocking agents, for example, alcohols and lactams, are used, a composition for a low-temperature curable coating as in the present invention can be used. I can't get things.

As described above, the blocked polyisocyanate used in the present invention can be obtained by reacting an aromatic polyisocyanate or a polyurethane prepolymer of an aromatic polyisocyanate with the above-mentioned blocking agent in a conventional manner. Can be. This reaction can be carried out in a solvent having no active hydrogen or without a solvent. Examples of the solvent having no active hydrogen include, for example, ethyl acetate,
Butyl acetate, cellosolve acetate, carbitol acetate, ester system such as dimethyl ester of dibasic acid,
Ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, toluene, xylene, sorbetso # 100, sorbetso # 150, sorbetso #
And aromatic solvents such as 200.

In the blocking reaction of the polyisocyanate, a conventionally known catalyst such as a tertiary amine, a metal salt or an organometallic compound may be used. The reaction temperature is usually about 0 to 100 ° C. When the isocyanate groups of the polyisocyanate or prepolymer are completely blocked, they can be diluted with a solvent having active hydrogen.

The coating composition according to the present invention contains, together with the above-mentioned blocked polyisocyanate, a polyamine polyether polyester which is a condensate of a polyamine polyether which is an adduct of ethylene oxide or tetrahydrofuran to a polyamine and an organic carboxylic acid. .

This polyamine polyether polyester, first,
The polyamine can be obtained by adding ethylene oxide or tetrahydrofuran to the polyamine to obtain a polyamine polyether, and then reacting the polyamine polyether with an organic carboxylic acid such that the hydroxyl groups are in excess with respect to the carboxyl groups. It has a primary hydroxyl group in the molecule.

In the above, as the polyamine, for example, ethylenediamine, diethylenetriamine, triethylenetetraamine, tetraethylenepentamine, pentaethylenehexamine, alkylenediamines and polyalkylenediamines such as hexamethylenediamine, and further, xylylenediamine, 4,4 ' -Methylenebis (cyclohexylamine), 3-aminomethyl-3,5,5-trimethylcyclohexylamine, bis (aminomethyl) cyclohexane,
Any compound having two or more amino groups in the molecule, such as 1-methyl-2,4-diaminocyclohexane, can be used.

A polyamine polyether can be obtained by subjecting ethylene oxide or tetrahydrofuran to ring-opening addition polymerization using the polyamine as an initiator compound.

The polyamine polyether polyester used in the present invention is obtained by reacting such a polyamine polyether with an organic carboxylic acid. Here, as the organic carboxylic acid, a monobasic acid or a polybasic acid having 6 to 50 carbon atoms is used. As the monobasic acid, for example,
Caproic acid, caprylic acid, lauric acid, tridecylic acid,
Examples of myristic acid, palmitic acid, stearic acid, behenic acid and the like, and examples of polybasic acid include polymerized vegetable oil fatty acids such as adipic acid, azelaic acid, sebacic acid, dodecane diacid and dimer acid.

The reaction between the polyamine polyether and the organic carboxylic acid is carried out by heating them to about 150 to 220 ° C. while removing formed water according to a conventional method. If necessary, a catalyst such as an organic acid or an inorganic acid may be used.

The coating composition according to the present invention has an equivalent ratio of the number of blocked isocyanate groups in the blocked polyisocyanate to the number of active hydrogens of about 0.1 to 10, preferably about 0.2 to 10.
5, particularly preferably in the range of about 0.4 to 2, in which the blocked polyisocyanate and the polyamine polyether polyester are mixed. Further, if necessary, other curing agents may be blended.

The coating composition according to the present invention as described above can be used as it is as a chipping-resistant coating, but in order to impart more sufficient chipping resistance, an appropriate pigment, dye, leveling agent, anti-sagging agent is used. , A catalyst, a stabilizer and the like are preferably compounded and used. This compounding is carried out by using a resin component composed of a blocked polyisocyanate and a polyamine polyether polyester, and pigments such as calcium carbonate, titanium white, carbon black, etc., and, if necessary, fine powder as a catalyst or a thixotropic agent. It can be carried out by mixing anhydrous silica such as Aerosil (manufactured by Degutta, West Germany) or the like in an appropriate solvent.

In general, block polyisocyanates and polyamine polyether polyesters facilitate their own handling, enhance the dispersibility of each component during the compounding described above, and furthermore, the spray properties as a paint and the volatilization during baking. In consideration of the properties, it is advantageous to use it after diluting it with an appropriate solvent so as to have an appropriate viscosity.

Preferred solvents used for such purposes include organic solvents having no active hydrogen, such as aliphatic, alicyclic and aromatic hydrocarbons, ketones, esters, and ethers. . As a specific example, for example,
As aliphatic hydrocarbons, for example, n-hexane having 6 to 20 carbon atoms, heptane, octane, nonane, decane, etc., as alicyclic hydrocarbons, such as cyclohexane, aromatic hydrocarbons, for example, , Besides benzene, alkyl-substituted benzene such as toluene, xylene and ethylbenzene, polynuclear aromatic hydrocarbons such as naphthalene,
Examples include general marketed aromatic hydrocarbon solvents having a boiling point of about 100 to 300 ° C. derived from petroleum fractions.

As the ketones, for example, ketones having 3 to 15 carbon atoms such as aliphatic ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, and aromatic hydrocarbon ketones such as benzophenone are preferable. As the esters, for example, acetates such as methyl acetate, ethyl acetate, butyl acetate, amyl acetate, 2-ethylhexyl acetate, ethylene glycol, propylene glycol, diethylene glycol and the like, methyl ether acetate, ethylene ether acetate of glycols, Examples thereof include butyl ether acetate and DBE (mixed ester solvent manufactured by DuPont). These solvents are used alone or as a mixture.

Further, in addition to the solvents exemplified above, a nitrogen-containing solvent, a sulfur-containing solvent, and the like can also be used. Also, alcoholic solvents such as methanol, ethanol, propanol, butanol, 2-ethylhexanol, methyl cellosolve, butyl cellosolve, methyl, ethyl and butyl ether of propylene glycol, and oximes as blocking agents are also used as the blocking agents for the blocked polyisocyanate. It can be used within a range that does not adversely affect the production and does not cause deterioration in physical properties of the final cured coating film. In particular, by using oximes, the storage stability of the coating composition can be improved.

In the present invention, the above-mentioned solvent is usually used in the range of 50% by weight or less in the final coating composition obtained by compounding, but it does not prevent the use of more than 50% by weight. .

The coating composition according to the present invention, or a coating composition obtained by compounding the same, is not particularly limited, but usually, using an air spray or airless spray, etc., usually, a film after baking It is applied to the surface to be coated to a thickness of about 20 to 500 μm, and is heated at a temperature of 90 to 110 ° C. for about 10 to 20 minutes and baked to obtain a cured coating having excellent chipping resistance. A membrane can be obtained. Further, the coating composition or the coating composition according to the present invention gives a smooth cured coating film without baking at the time of baking.

The coating composition according to the present invention, or the coating composition obtained by compounding the same, can be completely cured at a temperature of 90 to 110 ° C., as described above, without using a catalyst. Optionally a tertiary amine,
Use of a conventionally known catalyst such as a metal salt or an organometallic compound may be used without any problem.

Effect of the Invention The coating composition according to the present invention comprises a blocked polyisocyanate obtained by blocking an aromatic polyisocyanate or a polyurethane prepolymer thereof with oximes, and a polyamine polyether polyester,
In particular, it has excellent low-temperature curability and gives a coating film completely cured by baking at a low temperature of 90 to 110 ° C.

Further, in general, the compounded coating composition is
Since it has a high viscosity and has thixotropic properties, for example, when it is thickly applied by an airless spray or the like, it is easy to cause sideways due to poor bubble removal of the coating film.

However, the coating composition according to the present invention, of course, itself, after compounding, is coated with the above-mentioned coating film thickness, and when baked, the coating film does not give rise to any side,
A smooth coating film can be obtained, and this coating film has remarkably excellent chipping resistance.

Thus, the coating composition according to the present invention or the coating composition after compounding is excellent in low-temperature curability, easily defoamed, and does not generate side when baking, so that a thick coating is possible. Thus, since sufficient chipping resistance can be imparted to the coating film, for example,
It can be suitably used as an automotive paint.

EXAMPLES Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to these examples.

Example 1 Tolylene diisocyanate (2,4 units / 2,6 units ratio = 80/2
0) 174.2 g, 312.5 g of polycaprolactone diol (PCL-212, manufactured by Daicel Chemical Industries, Ltd., molecular weight 1250) and 22.4 g of trimethylolpropane in 598 g of cellosolve acetate
In tetrabutyl-1,3-diacetoxystannoxane 0.1
After reacting at 80 ° C. for 2 hours in the presence of g, 88.8 g of methyl ethyl ketoxime was gradually added dropwise to obtain a blocked polyisocyanate solution having a regenerated isocyanate group content of 3.51% and a solid content of 50%.

On the other hand, 485 g of ethylene oxide adduct (OH value 868) to diethylene triamine and 289 g of polymerized vegetable oil fatty acid (Versa Dime 216 manufactured by Henkel Hakusui Co., Ltd.) are removed from the reaction system with nitrogen until water is no longer generated. ,
Heated at 180-220 ° C. After completion of the reaction, a DBE solvent was added to obtain a polyamine polyether polyester solution having an OH value of 290 and a solid content of 60%.

1196 g of the above blocked polyisocyanate solution, 194 g of the above polyamine polyether polyester solution, 1050 g of calcium carbonate, 60 g of titanium white, 30 g of Aerosil,
A coating composition was obtained by mixing 1 g of carbon black and 320 g of butyl acetate.

The coating composition was applied using an airless spray so as to have a thickness of 200 μm after baking, and was heated and baked at 110 ° C. for 20 minutes to obtain a completely cured coating film. As shown in Table 1, the coating film was excellent in chipping resistance.

Example 2 251 g of 4,4'-diphenylmethane diisocyanate, 195 g of polytetramethylene glycol having a molecular weight of about 650 and 17.9 g of trimethylolpropane were added to 0.1 g of dibutyltin laurate in 552 g of Solvesso 100 (manufactured by Exxon Chemical Co., Ltd.). The reaction was carried out at 80 ° C. for 2 hours in the presence. Thereafter, 88.9 g of methyl ethyl ketoxime was gradually added dropwise to the reaction product,
A blocked polyisocyanate solution having a regenerated isocyanate group content of 3.81% and a solid content of 50% was obtained.

On the other hand, 236 g of an ethylene oxide adduct to ethylenediamine (OH number 950) and 177 g of a higher dibasic acid mixture (ULB-20 manufactured by Okamura Oil Co., Ltd.) were removed from the reaction system while removing generated water with nitrogen. 180-200 until no more water comes out
Heated at ° C. After completion of the reaction, cyclohexanone as a solvent was added to obtain a polyamine polyether polyester solution having an OH value of 255 and a solid content of 60%.

1324 g of the above blocked polyisocyanate solution, 220 g of the above polyamine polyether polyester solution, 1200 g of calcium carbonate, 60 g of titanium white, 30 g of Aerosil,
1 g of carbon black was added to 370 g of cellosolve acetate, and mixed uniformly to obtain a coating composition.

The coating composition was applied using an airless spray so as to have a thickness of 200 μm after baking, and was heated and baked at 110 ° C. for 20 minutes to obtain a completely cured coating film. As shown in Table 1, the coating film was excellent in chipping resistance.

Example 3 Crude 4,4'-diphenylmethane diisocyanate (Millionate MR-20 manufactured by Nippon Polyurethane Industry Co., Ltd.)
0) 250 g of polyhexylene adipate having a molecular weight of 1000 and 270 g
And trimethylolpropane 17.9 g in butyl acetate 636 g in tetrabutyl-1,3-diacetoxystannoxane 0.1
After reacting at 80 ° C. for 2 hours in the presence of g, 97.7 g of methyl ethyl ketoxime was gradually added dropwise to obtain a blocked polyisocyanate solution having a regenerated isocyanate group content of 3.30% and a solid content of 50%. .

On the other hand, 410 g of ethylene oxide adduct to triethylenetetramine (OH value 821) and 200 g of lauric acid were heated at 180 to 220 ° C until water ceased while removing generated water from the reaction system with nitrogen. did. After completion of the reaction, xylene was added thereto to obtain a polyamine polyether polyester solution having an OH value of 276 and a solid content of 60%.

1271 g of the above blocked polyisocyanate solution, 223 g of polyamine polyether polyester solution, 1000 g of calcium carbonate, 150 g of talc, 60 g of titanium white, 30 g of Aerosil, 1 g of carbon black, and 330 g of Solvesso 100 (manufactured by Exxon Chemical Co., Ltd.) are mixed and painted. A composition was obtained.

This coating composition was applied using an airless spray so as to have a thickness of 200 μm after baking, and was baked at 110 ° C. for 20 minutes to obtain a completely cured coating film. As shown in Table 1, the coating film was excellent in chipping resistance.

Example 4 Tolylene diisocyanate (2,4 units / 2,6 units ratio = 65/3
5) 174.2 g, polycaprolactone diol having a molecular weight of 1250 (PCL-212 manufactured by Daicel Chemical Industries, Ltd.) 188 g, molecular weight 65
After reacting 97.5 g of polytetramethylene glycol and 17.9 g of trimethylolpropane in 566 g of xylene in the presence of 0.1 g of dibutyltin laurate at 80 ° C. for 2 hours, 88.8 g of methyl ethyl ketoxime was gradually added dropwise thereto. ,
A blocked polyisocyanate solution having a regenerated isocyanate group content of 3.71% and a solid content of 50% was obtained.

Separately, 955 g of an ethylene oxide adduct (OH value: 705) to 1,3-bisaminomethylcyclohexane and sebacic acid 1
01 g was heated at 180-220 ° C. while removing water from the reaction system with nitrogen until no more water came out. After the completion of the reaction, methyl isobutyl ketone was added to this to give an OH value of 35.
7. A polyamine polyether polyester solution having a solid content of 60% was obtained.

A coating composition was obtained by mixing 1132 g of the above blocked polyisocyanate solution, 157 g of the above polyamine polyether polyester solution, 600 g of calcium carbonate, 400 g of talc, 50 g of titanium white, 25 g of Aerosil, 1 g of carbon black and 300 g of butyl acetate.

The coating composition was applied using an airless spray so as to have a thickness of 200 μm after baking, and baked at 100 ° C. for 20 minutes to obtain a completely cured coating film. As shown in Table 1, the coating film was excellent in chipping resistance.

Example 5 Tolylene diisocyanate (2,4 units / 2,6 units ratio = 65/3
5) 174.2 g, 250 g of polytetramethylene glycol having a molecular weight of 1000 and 22.4 g of trimethylolpropane were reacted in 326 g of cellosolve acetate at 80 ° C. for 2 hours in the presence of 0.1 g of tetrabutyl-1,3-diacetoxystannoxane. Thereafter, 298.8 g of methyl ethyl ketoxime was gradually added dropwise to obtain a blocked polyisocyanate solution having a regenerated isocyanate group content of 3.92% and a solid content of 50%.

Separately, 473 g of ethylene oxide adduct to ethylenediamine (OH value: 950) and 289 g of polymerized vegetable oil fatty acid (Versa Dime 216 manufactured by Henkel Hakusui Co., Ltd.) are removed from the reaction system with nitrogen until water is no longer generated. , 180
Heated at ~ 200 <0> C. After completion of the reaction, a DBE solvent was added thereto to obtain a polyamine polyether polyester solution having an OH value of 317 and a solid content of 60%.

1072 g of the above blocked polyisocyanate solution and 177 g of the above polyamine polyether polyester solution, 1000 g of calcium carbonate, 50 g of titanium white, 25 g of Aerosil,
A coating composition was obtained by mixing 1 g of carbon black and 310 g of xylene.

The coating composition was applied using an airless spray so as to have a thickness of 200 μm after baking, and baked at 100 ° C. for 20 minutes to obtain a completely cured coating film. This coating has the properties As shown in Table 1, the performance was excellent in chipping resistance.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-52-59632 (JP, A) JP-A-64-43573 (JP, A) JP-A-61-73735 (JP, A) JP-A-58-1983 108261 (JP, A) JP-A-48-1027 (JP, A) Keiji Iwata, "Latest Polyurethane Application Technology", published by CMC Co., Ltd., August 1983; 172

Claims (1)

(57) [Claims] 1. A polyamine which is obtained by blocking (a) an aromatic polyisocyanate or a polyurethane prepolymer of an aromatic polyisocyanate having a terminal isocyanate group with an oxime, and (b) a polyamine. A low-temperature curable coating composition comprising: a polyamine polyether polyester which is a condensate of an organic carboxylic acid and a polyamine polyether which is an adduct of ethylene oxide or tetrahydrofuran.