JPH08239542A - Thermosetting resin composition, coating material composition, coating method and coated matter - Google Patents

Abstract

PURPOSE: To obtain a coating material composition for base coating capable of forming a coated membrane having an excellent outlook even when coating a coating material composition for high performance clear coating thereon and further having an improved curing properties, and excellent in chipping resistant, waterproof and solvent resistant properties. CONSTITUTION: This thermosetting resin composition is obtained by copolymerizing (a) 1-50wt.% ethylenic unsaturated monomer containing a dialkylamide group, (b) 1-65wt.% ethylenic unsaturated monomer containing a long chain carboxyl group, (c) 2-70wt.% ethylenic unsaturated monomer containing hydroxy group, (d) 0.1-50wt.% reaction accelerating ethylenic unsaturated monomer and (e) a suitable amount of the other copolymerizable ethylenic unsaturated monomer, and has 10-300 hydroxy group value, 2-100 acid value and 500-50000 number averaged molecular weight.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermosetting resin composition, and more specifically to a coating composition for a clear coat, which uses a polyfunctional resin to form a coating film with a high degree of crosslinking. The present invention relates to a thermosetting resin composition capable of forming a coating film having an excellent finished appearance even when applied on the above, a coating composition using the same, a coating method and a coated article.

[0002]

2. Description of the Related Art In the fields of automobile coating and other fields where a coating film having good decorativeness as well as corrosion protection is required,
It is customary to finish coat the substrate being coated with several paints. The finish coating is usually applied in two steps. First, a base coat containing a coloring pigment, a material such as a metal powder pigment for enhancing a metallic effect, a material necessary for exhibiting a flip-flop effect, and a material having other decorative properties is applied, and subsequently, the above-mentioned, Water resistance, corrosion resistance, while further enhancing the function of the base coat with decoration
A clear coat having a function of enhancing scratch resistance and the like is applied.

In recent years, the base coat has been integrated with the clear coat to form a coating film.
The so-called two-coat / one-bake coating method, in which the base coat is not baked by the method called on-wet, the base coat is applied, the clear coat is subsequently applied, and then both are simultaneously baked, is the mainstream.

With respect to the above clear coat, various measures have been taken to enhance the functionality and the like. For example, conventionally, aminoplast curing agents such as melamine resins have been used for the purpose of enhancing scratch resistance, but various curable resins for clear coat that do not use this curing system for the purpose of enhancing resistance to acid rain. Compositions have been proposed. Japanese Patent Laid-Open No. 4-363
No. 374, a half-esterified copolymer,
A technique is disclosed in which a compound having both an epoxy group and a hydroxyl group, an acrylic copolymer and the like, and a melamine resin are contained and the composition ratio thereof is devised to obtain both acid resistance and scratch resistance.

Further research has been conducted on the improvement of the clear coat, and since it is necessary to keep the amount of the solvent low even if the functional group concentration is increased in the curing system, a silicone is used as a so-called high solid composition having a high solid content concentration. The technology of incorporating polymers was invented. Further, in order to obtain higher appearance and scratch resistance, the inventors have come up with a technique of further blending a certain amount of a pigment dispersion resin such as an alkyd resin. Also,
In order to achieve the object essentially without using an aminoplast curing agent, a half-esterified copolymer and a polymer having both an epoxy group and a hydroxyl group are used as basic components, and an epoxy group is further added. A technique has been established in which a silicone polymer having both an alkenyl group and an alkoxyl group is blended as a third component. Nowadays, a coating composition for a clear coat which can sufficiently satisfy the so-called non-sand recoating property has also been developed.

By the way, since the above-mentioned clear coat coating composition is applied on the base coat for final coating, in order to obtain a high-appearance finished coating film,
It was necessary to devise not only the clear coat but also the base coat to improve the performance corresponding to this.

The above high-performance clear coat coating composition uses a resin having a high functional group concentration in order to improve acid resistance and the like, has a high SP value (solubility parameter), and is used as a clear coat coating composition. Had a greater ability to erode the basecoat than ever before. Therefore, when applied on a coating film composed of a coating composition for an existing base coat composed of a hydroxyl group-containing polymer, an aminoplast curing agent and the like, a brightening agent, a coloring pigment and other additives, the above clear coat The coating composition erodes the base coat, inhibits the base color of the intended pigment, loses the original glitter, loses the glossiness, or
In extreme cases, the swelling of the base coat resulted in a so-called ugly feeling (unsightly distorted feeling).

Therefore, in order to form a base coat coating composition suitable for the above-mentioned high performance clear coating coating composition, its cohesive force is increased, and it is also suitable in combination with a highly polar clear coating coating composition. A base coat paint that gives a finished appearance is considered essential, for example, an amide group-containing ethylenically unsaturated monomer,
A coating composition comprising a curable resin composition obtained by copolymerizing a long-chain carboxyl group-containing ethylenically unsaturated monomer, a hydroxyl group-containing ethylenically unsaturated monomer, and another copolymerizable ethylenically unsaturated monomer Was proposed.

[0009]

A coating composition comprising the above curable resin composition forms a coating film having an excellent finished appearance even when the above coating composition for high performance clear coat is applied thereon. In addition, it was possible to achieve a good effect on the chipping property. However, the curable resin composition has the disadvantage of poor compatibility with other resins due to the characteristics of the contained monomer, and therefore has a problem of curability.
In particular, the curability during low temperature baking at about 120 to 140 ° C. was insufficient. As a result, when a coating line or the like under low temperature baking conditions is used, there are drawbacks such as a decrease in chipping property and water resistance of the coating film.

In order to solve this, use of a catalyst is considered, but when the above curable resin composition is directly compounded with an acid catalyst as a so-called external catalyst to prepare a base coating, it is half-esterified. When used in combination with a high-performance clear coat coating composition containing both a copolymer and a polymer having both an epoxy group and a hydroxyl group as basic components, curing of such a high-performance clear coat coating composition There was the inconvenience of exerting the effect of impeding sex.

The present invention has been made in view of the above situation, and it is possible to form a coating film having an excellent finished appearance even when the above high performance clear coat coating composition is applied thereon. It is an object of the present invention to provide a coating composition for a base coat, which has improved curability and excellent properties such as chipping property, water resistance and solvent resistance.

[0012]

SUMMARY OF THE INVENTION The gist of the present invention is to provide dialkylamide group-containing ethylenically unsaturated monomers (a) 1 to
50% by weight, long chain carboxyl group-containing ethylenically unsaturated monomer (b) 1 to 65% by weight, hydroxyl group-containing ethylenically unsaturated monomer (c) 2 to 70% by weight, reaction accelerating ethylenically unsaturated monomer (d) 0.1 to 50% by weight, and other copolymerizable ethylenically unsaturated monomer (e)
A thermosetting resin composition itself, which is a composition obtained by copolymerizing an appropriate amount of 10 to 300, a hydroxyl value of 10 to 300, an acid value of 2 to 100, and a number average molecular weight of 500 to 50,000. It is in. Above (a) to (e)
The content ratio in each of the monomers means the solid content equivalent weight% with respect to the entire thermosetting resin composition. The gist of the present invention is also a coating composition using the thermosetting resin composition, a coating method using the coating composition, and a coated product obtained by coating the coating composition. The present invention is described in detail below.

The first component of the present invention is a dialkylamide group-containing ethylenically unsaturated monomer (a). The dialkylamide group-containing ethylenically unsaturated monomer (a)
Is an ethylenically unsaturated monomer having 1 to 1 carbon atoms
It contains a dialkylamide group having 0 alkyl group. Examples of such a dialkylamide group-containing ethylenically unsaturated monomer include N, N'-dimethyl (meth) acrylamide, N, N'-dibutyl (meth) acrylamide, N, N'-dioctyl (meth) acrylamide and the like. And dialkyl (meth) acrylamide of the above. Of these, preferably
N, N'-dimethylacrylamide, N, N'-dimethylmethacrylamide, N, N'-dibutylacrylamide, N, N'-dibutylmethacrylamide, and more preferably N, N'-dimethylacrylamide, N,
It is N'-dimethylmethacrylamide. These monomers may be used alone or in combination of two or more.

The dialkylamide group-containing ethylenically unsaturated monomer (a) is used in an amount of 1 to 50% by weight in terms of solid content based on the total amount of the thermosetting resin composition of the present invention. When the content of the dialkylamide group-containing ethylenically unsaturated monomer (a) is less than 1% by weight, the finished appearance is deteriorated and the chipping property is deteriorated, and when it exceeds 50% by weight, the solvent detergency and water resistance are deteriorated. Therefore, it is limited to the above range.
It is preferably 3 to 40% by weight, more preferably 5 to 25% by weight. In the present invention, from the viewpoint of curability, a dialkylamide group-containing ethylenically unsaturated monomer (a)
However, even if an amide group-containing ethylenically unsaturated monomer such as acrylamide or methacrylamide is used in place of the above dialkylamide group-containing ethylenically unsaturated monomer (a), the effect of the present invention can be kept constant. It is possible to achieve a degree.

The second component of the present invention is a long chain carboxyl group-containing ethylenically unsaturated monomer (b). The long chain carboxyl group-containing ethylenically unsaturated monomer (b)
Can be obtained by half-esterifying the hydroxyalkyl (meth) acrylate (b ² ) represented by the following general formula (I) with the acid anhydride group-containing compound (b ³ ) in an equimolar ratio.

[0016]

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In the formula, R represents hydrogen or a methyl group. m
Is an integer of 2 to 8, preferably 2 to 6. n is 3
It is an integer of -7, preferably 3-5. q is 0 to 4,
It is preferably an integer of 0 to 2.

Examples of the hydroxyalkyl (meth) acrylate (b ² ) represented by the above general formula (I) include hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate and 4-hydroxybutyl acrylate. You can Furthermore, a reaction product with these ε-caprolactone and the like can be mentioned. Examples of such compounds include "Plaxel FA-1" and "Plaxel FM-" manufactured by Daicel Chemical Industries, Ltd.
1 "," Plaxel FA-2 "," Plaxel FM-
2 "," Plaxel FA-3 "," Plaxel FM-
3 ”and the like. Of these, hydroxyethyl (meth) acrylate, "Plaxel FA-1" and "Plaxel FM-1" are preferable, and hydroxyethyl acrylate is more preferable.

The acid anhydride group-containing compound (b ³ ) is not particularly limited as long as it is a compound having a carboxy functionality capable of reacting with a hydroxyl group under ordinary reaction conditions such as room temperature to 150 ° C. and normal pressure. However, examples thereof include hexahydrophthalic anhydride, 4-methylhexahydrophthalic anhydride, phthalic anhydride, succinic anhydride, tetramethylmaleic anhydride and maleic anhydride.
Of these, 4-methylhexahydrophthalic anhydride,
Hexahydrophthalic anhydride and succinic anhydride are preferred,
More preferred is succinic anhydride.

The half-esterification reaction of the hydroxyalkyl (meth) acrylate (b ² ) represented by the general formula (I) with the acid anhydride group-containing compound (b ³ ) is carried out by a conventional method at room temperature to 150 ° C. Done in. At this time, it is preferable to use an excess amount of hydroxyalkyl (meth) acrylate (b ² ) so that unreacted acid anhydride groups do not remain.

In the above-mentioned half-esterification reaction, when the hydroxyalkyl (meth) acrylate (b ² ) is added in excess of the amount required for half-esterification and reacted with the anhydride group-containing compound (b ³ ), A monomer mixture of a chain carboxyl group-containing ethylenically unsaturated monomer and a hydroxyl group-containing ethylenically unsaturated monomer is obtained, and the hydroxyl group-containing ethylenically unsaturated monomer is the other copolymerizable ethylenically unsaturated monomer described later ( e) can be used.

In the half-esterification reaction, the mixing ratio of the hydroxyalkyl (meth) acrylate (b ² ) and the acid anhydride group-containing compound (b ³ ) is (the number of moles of acid anhydride group) / (Number of moles of hydroxyl group) = 0.5 /
It is preferably 1.0 to 1 / 1.0. If the mixing ratio is less than 0.5 / 1.0, the amount of carboxyl groups is too small and the curability becomes insufficient, and if it exceeds 1 / 1.0, half esterification takes time and the monomer gels. There is a risk. More preferably, 0.8 / 1.0 to 1 /
It is 1.0.

The long chain carboxyl group-containing ethylenically unsaturated monomer (b) is used in an amount of 1 to 65% by weight in terms of solid content based on the total amount of the thermosetting resin composition of the present invention. When the content of the long chain carboxyl group-containing ethylenically unsaturated monomer (b) is less than 1% by weight, the finished appearance is deteriorated and the chipping property is deteriorated, and when it exceeds 65% by weight, the hardness,
Since the water resistance decreases, it is limited to the above range. It is preferably 3 to 50% by weight, more preferably 5 to 30% by weight.

The third component of the present invention is a hydroxyl group-containing ethylenically unsaturated monomer (c). The hydroxyl group-containing ethylenically unsaturated monomer (c) is not particularly limited,
For example, 2-hydroxyethyl (meth) acrylate,
2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate and the like can be mentioned, and further, a reaction product thereof with ε-caprolactone and the like can be mentioned. . Examples of such a compound include “Plaxel FA-1”, “Plaxel FM-1”, “Plaxel FA-2”, “Plaxel FM-2”, “Plaxel FA-3”, and “Plaxel FA-3” manufactured by Daicel Chemical Industries, Ltd. Praxel FM-3 "and the like. 2-of these
Hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, "Plaxel FA-1",
"Plaxel FM-1", "Plaxel FA-2",
"Plaxel FM-2" is preferred.

If the above-mentioned hydroxyl group-containing ethylenically unsaturated monomer (c) is not used, the functional group concentration of the copolymer obtained is not sufficiently high, which is not preferable. The hydroxyl group-containing ethylenically unsaturated monomer (c) is used in an amount of 2 to 70% by weight in terms of solid content based on the total amount of the thermosetting resin composition of the present invention. When the content of the hydroxyl group-containing ethylenically unsaturated monomer (c) is less than 2% by weight, curability, water resistance and weather resistance are deteriorated, and when it exceeds 70% by weight, water resistance is decreased and flexibility is insufficient. Therefore, it is limited to the above range. Preferably 3
-50% by weight, more preferably 5-40% by weight.

The fourth component of the present invention is a reaction accelerating ethylenically unsaturated monomer (d). The reaction-promoting ethylenically unsaturated monomer (d) is an ethylenically unsaturated monomer having a function of promoting the curing reaction. Examples of the reaction accelerating ethylenically unsaturated monomer (d) include sulfonic acid group-containing ethylenically unsaturated monomers,
Examples thereof include an ethylenically unsaturated monomer having a phosphoric acid group. The ethylenically unsaturated monomer having a sulfonic acid group is not particularly limited, and examples thereof include those represented by the following general formula (II), general formula (III), and general formula (IV).

[0027]

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In the formula, R ¹ represents hydrogen or a methyl group.
R ² represents a linear or branched saturated hydrocarbon chain having 1 to 5 carbon atoms.

[0029]

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In the formula, R ³ represents hydrogen or a methyl group.
R ⁴ represents a linear or branched saturated hydrocarbon chain having 1 to 5 carbon atoms.

[0031]

[Chemical 4]

In the formula, R ⁵ represents hydrogen or a methyl group.
X represents a linear or branched unsaturated hydrocarbon chain having 2 to 4 carbon atoms. s is an integer of 1 to 30.

[0033] Of these, R ² is, those which are saturated hydrocarbon chain of 2 carbon atoms; R ² is, those which are straight-chain saturated hydrocarbon chain of 3 carbon atoms; R ⁴ is, min 4 carbon atoms A saturated hydrocarbon chain having a branch and having a tertiary carbon atom at the 2-position counted from the sulfonic acid group; XO is ethylene oxide and s is 1 to 5; XO is propylene oxide And those in which s is 1 to 5 are preferred, and R
⁴ is a saturated hydrocarbon chain having 4 carbon atoms and having a tertiary carbon atom at the 2-position counted from the sulfonic acid group; XO is ethylene oxide, and s is 1 to
5; XO is propylene oxide, s
Is more preferably 1 to 5.

The above-mentioned ethylenically unsaturated monomer having a phosphoric acid group is not particularly limited, and examples thereof include those represented by the following general formula (V), general formula (VI) and general formula (VII). You can

[0035]

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In the formula, R ⁶ represents hydrogen or a methyl group.
R ⁷ represents a linear or branched saturated hydrocarbon chain having 1 to 5 carbon atoms.

[0037]

[Chemical 6]

In the formula, R ⁸ represents hydrogen or a methyl group.
R ⁹ represents a straight or branched saturated hydrocarbon chain having 1 to 5 carbon atoms.

[0039]

[Chemical 7]

In the formula, R ¹⁰ represents hydrogen or a methyl group.
Y represents a linear or branched unsaturated hydrocarbon chain having 2 to 4 carbon atoms. t is an integer of 1 to 30.

Of these, R ⁷ is a saturated hydrocarbon chain having 2 carbon atoms; R ⁷ is a saturated saturated hydrocarbon chain having 3 carbon atoms, which is 1 from the phosphate group. Having a secondary carbon atom in position; R ⁷ is a branched saturated hydrocarbon chain having 4 carbon atoms, which is 1 from the phosphate group
Having a tertiary carbon atom in position; YO is ethylene oxide and s is 1 to 5; YO is propylene oxide and s is preferably 1 to 5; R ⁷ is A saturated hydrocarbon chain having 2 carbon atoms; Y
More preferably, O is ethylene oxide and s is 1 to 5; YO is propylene oxide and s is 1 to 5.

The content of the reaction accelerating ethylenically unsaturated monomer (d) is 0.1 to 50% by weight in terms of solid content based on the total amount of the thermosetting resin composition of the present invention. 0.
If it is less than 1% by weight, curability is insufficient and chipping property,
Solvent resistance, water resistance, especially water shrinkage resistance deteriorates, and when it exceeds 50% by weight, flexibility, storage stability, water resistance, particularly whitening resistance deteriorates, so the content is limited to the above range. It is preferably 1 to 40% by weight, more preferably 2 to 30% by weight.

Generally, in the coating composition, for the purpose of improving the curability, a method of adding an external catalyst such as sulfonic acid type or phosphoric acid type or introducing an acid group such as sulfonic acid or phosphoric acid into the acrylic resin is used. Are known. However, when the method of adding an external catalyst is adopted, compatibility with a clear coating to be combined may be a problem, and in the present invention,
There are also problems to solve. In the present invention, in the polymer having a functional group having a strong intermolecular cohesive force such as acrylamide, by introducing the monomer having the acid group, it is possible to improve the curability, and It is based on the technical idea of solving the problem of suitability, and is completely different in the purpose and constitution from the conventional method for acrylic resin.

The fifth component of the present invention is another copolymerizable ethylenically unsaturated monomer (e). As the other copolymerizable ethylenically unsaturated monomer (e), a neutral ethylenically unsaturated monomer is used. In addition, a carboxyl group-containing ethylenically unsaturated monomer and an alicyclic hydrocarbon-containing ethylene are also used. An unsaturated monomer or the like can be used.

The above-mentioned neutral ethylenically unsaturated monomer is not particularly limited and includes, for example, styrene; methyl acrylate, ethyl acrylate, isopropyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate,
Cyclohexyl acrylate, -n-butyl acrylate,
Examples thereof include acrylic acid esters such as -t-butyl acrylate and lauryl (meth) acrylate.

The carboxyl group-containing ethylenically unsaturated monomer is not particularly limited, and examples thereof include acrylic acid, methacrylic acid and long-chain carboxylic acid. A long-chain carboxylic acid is preferred.

Examples of the above-mentioned alicyclic hydrocarbon-containing ethylenically unsaturated monomer include bridged hydrocarbon-containing ethylenically unsaturated monomer and the like.
Examples thereof include isobornyl (meth) acrylate, cyclohexyl (meth) acrylate, t-butylcyclohexyl (meth) acrylate, dicyclopentadienyl (meth) acrylate, and dihydrodicyclopentadienyl (meth) acrylate. Of these, isobornyl (meth) acrylate, dicyclopentadienyl (meth) acrylate and dihydrodicyclopentadienyl (meth) acrylate are preferable, and isobornyl (meth) acrylate is more preferable.

The hydroxyl value of the thermosetting resin composition of the present invention is 10 to 300. When the hydroxyl value is less than 10, curability, water resistance and weather resistance are insufficient, and when it exceeds 300, flexibility is insufficient, so that the content is limited to the above range. It is preferably 20 to 200, more preferably 40 to 100.

The acid value of the thermosetting resin composition of the present invention is 2
~ 100. If the acid value is less than 2, the curability is insufficient, and if it exceeds 100, the water resistance is insufficient, so the content is limited to the above range. It is preferably 5 to 80, more preferably 10 to 50.

The number average molecular weight of the thermosetting resin composition of the present invention is 500 to 50,000. Number average molecular weight is 50
When it is less than 0, the finished appearance is poor and the curability is insufficient,
Even if it exceeds 50,000, the finished appearance is deteriorated, so it is limited to the above range. Preferably 1000-30000
And more preferably 1500 to 20000.
The number average molecular weight can be determined by gel permeation chromatography (GPC) or the like.

The copolymerization reaction of the above components (a) to (e) can be carried out by a known method, for example, by solution polymerization such as radical polymerization, under normal pressure or under pressure, at a polymerization temperature. It can be carried out at 80 to 140 ° C. and a polymerization time of 3 to 8 hours. Examples of the polymerization initiator used at this time include peroxides such as benzoyl peroxide, t-butyl peroxide and cumene hydroperoxide; organic azo compounds such as azobiscyanovaleric acid and azobisisobutyronitrile. Examples thereof include azo compounds and the like, and of these, t-butylperoxy-2-ethylhexanoate and the like are preferably used. They are,
An addition amount of 1 to 20 parts by weight is preferable with respect to 100 parts by weight of all monomers. The reaction solvent for the copolymerization reaction is not particularly limited, and examples thereof include toluene, n-butanol, and propylene glycol monomethyl ether.

In the present invention, the coating composition of the present invention can be obtained by using the thermosetting resin composition as a binder component. In the coating composition, in addition to the thermosetting resin composition, a resin that does not contain an amide group can be used as a pigment dispersion resin.
In the present specification, the “amide group-free resin” refers to an amide group-free acrylic resin, alkyd resin, epoxy resin or polyester resin. In the present invention, as the resin containing no amide group,
Those having a hydroxyl value of 20 to 100, an acid value of 5 to 50 and a molecular weight of 5,000 to 30,000 can be preferably used.

In the above coating composition, the thermosetting resin composition of the present invention and the above amide group-free resin are blended in the following manner: (weight of thermosetting resin composition) / (weight of resin not containing amide group) ) = 10/0 to 2/8, more preferably 10/0 to 1/2.

The coating composition may contain a melamine resin as a curing agent. As the melamine resin, a solvent type is preferable, and examples thereof include Uban 128, Uban 20N60, Uban 225 manufactured by Mitsui Toatsu Chemicals, Inc., and one or more of these may be used in combination. . Further, the amount of addition is based on the total weight of the thermosetting resin composition of the present invention and the resin not containing the amide group (the total of the thermosetting resin composition and the resin not containing the amide group. The ratio of (weight) / (weight of melamine resin) = 9/1 to 4/6 is preferable, and 7/3
A ratio of 5/5 is more preferable.

The above coating composition contains a pigment in addition to the above components. The above-mentioned pigments can be used in combination with a pigment-imparting pigment component and a pigment-imparting pigment component depending on the purpose of use such as a solid color film and a metallic film. Examples of the pigment include known color pigments, extender pigments, bright pigments, and the like. As the color pigment, for example,
Titanium dioxide, lead white, graphite, zinc sulfide, zinc oxide, chromium oxide, zinc chromate, strontium chromate, barium chromate, yellow nickel titanium, yellow chromium titanium, graphite, carbon black, iron oxide, yellow iron oxide, red Iron oxide, black iron oxide, phthalocyanine blue, phthalocyanine green, ultramarine blue,
Quinacridones, indanthrone, isoindolinone,
Examples thereof include perylene, anthrapyridine, benzimidazoline, cadmium sulfide, diketopyrrolopyrrole and the like. Examples of the extender pigment include inorganic substances such as calcium carbonate, magnesium carbonate, barium sulfate, silicic acid, silicate, aluminum hydrate, and calcium sulfate. Examples of the bright pigment include mica pigment; aluminum foil; bronze foil; tin foil; gold foil; silver foil; copper foil; metal titanium foil; stainless steel foil; nickel foil; chromium, cobalt sulfide, manganese sulfide, titanium sulfide and the like. Examples thereof include metal alloy foils; metal foils coated with plastics; metal foil pigments selected from foil phthalocyanine blue and the like.

The pigment content in the above coating composition is usually
Expressed as a weight percentage with respect to the solid content in the coating composition, preferably 1 to 50% by weight, more preferably 5 to 40% by weight. The pigment is contained in the coating composition by forming a pigment paste with the thermosetting resin composition and the dispersion resin. The pigment paste can be formed by a known method using a ball mill, a sand mill, or the like.

In producing the coating composition of the present invention, any organic solvent usually used in coating materials or a mixed solution thereof can be used as a solvent. Examples of such a solvent include alcohols such as methanol, ethanol, propanol, butanol, isopropanol, ethoxyethanol, ethoxypropanol, and methoxypropanol; esters such as ethyl acetate, methyl acetate, butyl acetate; γ-butyrolactone, etc. Lactones; aromatic hydrocarbons such as toluene and xylene; ethers such as dibutyl ether and ethylene glycol diethyl ether; amides such as N-methylpyrrolidone are preferably used.

In order to improve the weather resistance of the coating film, an ultraviolet absorber such as benzophenone or benzotriazole, a hindered amide light stabilizer, an antioxidant such as phenol or the like is added to the above coating composition. May be. Further, as other additives, crosslinked resin particles as a rheology control agent (controlling agent for sag etc.), a surface conditioner for adjusting the appearance of the coating film, etc. may be blended. For adjusting the viscosity of the coating composition, etc., as a diluent, for example,
Alcohol-based solvents such as methanol, ethanol, propanol, butanol; hydrocarbon-based solvents; ester-based solvents and the like may be used.

In the present invention, the above coating composition can be applied by spray coating, brush coating, dip coating, roll coating, flow coating or the like. The coating method in the case of applying the coating composition on the article to be coated may be an ordinary method, but after forming an undercoat and an intermediate coating film on the article to be coated, the coating composition is applied. A method of applying as a base coat and further applying a clear coat by a so-called wet-on-wet coating method may be adopted.

The clear coat coating composition used in combination with the coating composition of the present invention may use an aminoplast curing agent such as a melamine resin, but does not use an aminoplast curing agent. May be Examples of such clear coat coating composition that does not use an aminoplast curing agent include, for example, a carboxyl group-containing resin (f) and an epoxy group-containing resin (g).
A coating composition for clear coat containing both of these is preferably used.

The carboxyl group-containing resin (f) means
It is an acrylic polymer (f ² ) or a polyester polymer (f ³ ) containing a carboxyl group in the molecule. The acrylic polymer (f ² ) containing a carboxyl group in the molecule is not particularly limited, and examples thereof include those obtained by polymerizing an ethylenically unsaturated monomer by a known method. Examples of the ethylenically unsaturated monomer include carboxyl group-containing ethylenically unsaturated monomers such as (meth) acrylic acid, itaconic acid, and maleic acid; methyl (meth) acrylate, ethyl (meth) acrylate, (meth) Propyl acrylate,
Butyl acrylate, n-propyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-acrylic acid
(Meth) acrylic acid alkyl esters such as ethylhexyl, acrylic acid n-octyl, acrylic acid n-dodecyl; styrene, α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, pt
Examples thereof include styrene derivatives such as butyl styrene. Furthermore, hydroxymethyl (meth) acrylate,
It may be an ethylenically unsaturated monomer containing a hydroxyl group such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, and hydroxyhexyl (meth) acrylate.

The above-mentioned acrylic polymer (f ² ) containing a carboxyl group in the molecule is an ethylenically unsaturated monomer having an acid group in an amount of 3.5 to 45% by weight, preferably 7 to 40% by weight.
%, More preferably 10 to 30% by weight, and 97.5 to 55% by weight of other copolymerizable monomers, preferably 9%.
3-60 wt%, and more preferably can be suitably used those obtained (f ²³⁾ by copolymerizing 90 to 70 wt%. The acrylic polymer (f ² ) containing a carboxyl group in the molecule has a number average molecular weight of 50.
0 to 20000, preferably 1000 to 12000, more preferably 1500 to 8000, and an acid value of 30 to 2
50, preferably 60 to 200, more preferably 90 to
160.

More preferable acrylic polymer (f ² ) is an acid anhydride group-containing polymer (f ² a).
Examples thereof include a polymer (f ²⁴ ) containing a carboxyl group and a carboxylic acid ester group, which is obtained by reacting a monoalcohol (f ² b) with the above.

The acid anhydride group-containing polymer (f ² a)
Can be obtained by copolymerizing an acid anhydride group-containing ethylenically unsaturated monomer with another copolymerizable ethylenically unsaturated monomer. Examples of the acid anhydride group-containing ethylenically unsaturated monomer include itaconic anhydride, maleic anhydride, citraconic anhydride, and the like. The other copolymerizable ethylenically unsaturated monomer is not particularly limited as long as it does not adversely affect the acid anhydride group, and examples thereof include styrene; α-methylstyrene;
Methyl acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, cyclohexyl (meth) acrylate, etc. (Meth) acrylic acid ester; Veva-made by Shell Co.
9, Veova-10 manufactured by Shell Co .; acrylic acid, methacrylic acid and the like can be mentioned.

The above acid anhydride group-containing ethylenically unsaturated monomer is used in an amount of 15 to 40% by weight based on all monomers.
If the amount used is less than 15% by weight, the curability will be insufficient and 40
If it exceeds 5% by weight, it becomes too hard and the weather resistance is insufficient. It is preferably 15 to 30% by weight.

The number average molecular weight of the acid anhydride group-containing polymer (f ² a) is preferably 500 to 20,000. When the number average molecular weight exceeds 20,000, the viscosity of the polymer becomes high and it becomes difficult to prepare a coating composition having a high solid content, and when it is less than 500, the curability of the coating composition becomes insufficient. More preferably, it is 1000 to 10,000. The acid anhydride group-containing polymer (f ² a) preferably has an average of 2 to 15 acid anhydride groups in one molecule. 1
If the average number of acid anhydride groups in the molecule is less than 2, the curability of the resulting coating composition will be insufficient, and if it exceeds 15, the composition will be too hard and the weather resistance will be insufficient.

As the above monoalcohol (f ² b),
Those having 1 to 12 carbon atoms, more preferably those having 1 to 8 carbon atoms, are suitable for regenerating the acid anhydride group by volatilizing the alcohol because they volatilize when heated, and examples thereof include methanol, ethanol and n. -Propanol, isopropanol, t-propanol, n-butanol, isobutanol, t-butanol, methyl cellosolve, ethyl cellosolve, dimethylaminoethanol, diethylaminoethanol, acetol, allyl alcohol, propargyl alcohol and the like can be mentioned. More preferably acetol, allyl alcohol, propargyl alcohol,
It is methanol.

The polymer (f ²⁴ ) having a carboxyl group and a carboxylic acid ester group is obtained by adding the acid anhydride group-containing polymer (f ² a) and the monoalcohol (f ² b) to Number) / (moles of hydroxyl group) = 1 /
It is obtained by reacting at a ratio of 1.5 to 1 / 1.0. If the above molar ratio is less than 1 / 1.5, the alcohol is excessive and cracking occurs at the time of curing. If it exceeds 1 / 1.0, unreacted acid anhydride groups remain and storage stability deteriorates. It is preferably 1 / 1.5 to 1 / 1.3.

The polymer (f ²⁴ ) having a carboxyl group and a carboxylic acid ester group has an acid value of 30 in terms of solid content.
It is preferably about 250 mg KOH / g. Acid value is 30
If it is less than mgKOH / g, the curability will be insufficient and 2
If it exceeds 50 mgKOH / g, it becomes too hard and the weather resistance becomes poor. More preferably 80-200 mgKOH /
g.

In the carboxyl group-containing polymer (f), the carboxyl group-containing polyester polymer (f
Examples of ³ ) include those having a terminal carboxyl group prepared by a condensation reaction of a polyhydric alcohol and a polybasic acid or a polybasic acid anhydride. Examples of the polyhydric alcohol include ethylene glycol, propylene glycol, 1,3-butylene glycol, 1,6-hexanediol, diethylene glycol, dipropylene glycol, neopentyl glycol, triethylene glycol, hydrogenated bisphenol A and phenol dihydroxy. Propyl ether, glycerin, trimethylol ethane, trimethylol propane, pentaerythritol, dipentaerythritol and the like can be mentioned.

Examples of the polybasic acid or polybasic acid anhydride include phthalic acid, isophthalic acid, terephthalic acid,
Dibasic acids such as succinic acid, adipic acid, azelaic acid, sebacic acid, tetrahydrophthalic acid, hexahydrophthalic acid, maleic acid, fumaric acid; succinic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, Examples thereof include acid anhydrides such as hymic acid anhydride, trimellitic acid anhydride, methylcyclohexene tricarboxylic acid anhydride, and pyromellitic acid anhydride. Further, for example, oils and fats such as castor oil, coconut oil, linseed oil, palm kernel oil, safflower oil, soybean oil, tung oil, tall oil; fatty acids; monofunctional carboxylic acids such as dehydrated castor oil You can

The polyester polymer (f ³ ) can be obtained by a usual esterification reaction and has a number average molecular weight of 500 to 20,000, preferably 600 to 1,000.
0, more preferably 700 to 6000 and an acid value of 3
0 to 250 mg KOH / g, preferably 60 to 200 m
gKOH / g, more preferably 90-160 mgKOH
/ G.

The epoxy group-containing resin (g) has 2 to 10 epoxy groups, preferably 3 to 8 epoxy groups in one molecule, and preferably has an epoxy equivalent of 280 to 900. When the epoxy equivalent is less than 280, the coating film obtained becomes too hard and the resulting coating becomes brittle, and when it exceeds 900, the curability of the coating composition becomes insufficient. It is more preferably 300 to 800.

As the above epoxy group-containing resin (g),
Epoxy group-containing ethylenically unsaturated monomers 10-6
An acrylic polymer (g ² ) obtained by copolymerizing 0% by weight and 90 to 40% by weight of another copolymerizable ethylenically unsaturated monomer can be mentioned.

Examples of the ethylenically unsaturated monomer having an epoxy group include those having a glycidyl group such as glycidyl (meth) acrylate and 3,4-epoxycyclohexanylmethyl (meth) acrylate. it can.

Examples of the other copolymerizable ethylenically unsaturated monomer include styrene; α-methylstyrene; methyl acrylate, ethyl (meth) acrylate,
Propyl (meth) acrylate, n- (meth) acrylic acid
Butyl, isobutyl (meth) acrylate, t-butyl (meth) acrylate, cyclohexyl (meth) acrylate, and other (meth) acrylic acid esters; Shell's Veov
a-9, Veova-10 manufactured by Shell Co .; acrylic acid, methacrylic acid and the like.

More preferable epoxy group-containing resin (g) has a hydroxyl equivalent of 280 to 1200 and an epoxy group-containing ethylenically unsaturated monomer 10.
˜60% by weight, 5-40% by weight of an ethylenically unsaturated monomer having a hydroxyl group, and a molecular weight of 500˜20000 obtained by copolymerizing an appropriate amount of another ethylenically unsaturated monomer.
Preferably mention may be made of an acrylic polymer (g ³⁾ or the like of 1000 to 12,000.

The acrylic polymer (g ³ ) contains 2 to 12, preferably 4 to 10 hydroxyl groups in one molecule. The hydroxyl equivalent of the acrylic polymer (g ³ ) is 28.
0 to 1200 is preferable. If the hydroxyl equivalent is less than 280, the water resistance of the resulting coating film will be insufficient, and if it exceeds 1200, the curability will be insufficient.

Examples of the epoxy group-containing ethylenically unsaturated monomer contained in the acrylic polymer (g ³ ) include glycidyl (meth) acrylate, 3,
4-epoxycyclohexanylmethyl (meth) acrylate etc. can be mentioned. The content of the ethylenically unsaturated monomer having an epoxy group is preferably 10 to 60% by weight. If it is less than 10% by weight, the curability is insufficient, and if it exceeds 60% by weight, the weather resistance of the obtained coating film is insufficient. It is more preferably 15 to 50% by weight.

The hydroxyl group-containing ethylenically unsaturated monomer contained in the acrylic polymer (g ³ ) may, for example, be a hydroxyalkyl (meth) acrylate represented by the following formula (I). The content of the hydroxyalkyl (meth) acrylate is preferably 5 to 40% by weight. When the content of hydroxyalkyl (meth) acrylate is less than 5% by weight, curability is insufficient and 40
If it exceeds 5% by weight, the compatibility with other monomers is insufficient and the reaction does not proceed sufficiently. More preferably 15 to 30% by weight
Is.

[0081]

Embedded image

In the formula, R represents hydrogen or a methyl group. m
Is an integer of 2 to 8, preferably 2 to 6. n is 3
It is an integer of -7, preferably 3-5. q is 0 to 4,
It is preferably an integer of 0 to 2.

Examples of the other ethylenically unsaturated monomers contained in the acrylic polymer (g ³ ) include styrene; α-methylstyrene; methyl acrylate, ethyl (meth) acrylate, and (meth) acrylic acid. Propyl, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate,
(Meth) acrylic acid esters such as cyclohexyl (meth) acrylate; Veova-9 manufactured by Shell Co., Veova-10 manufactured by Shell Co .; acrylic acid; methacrylic acid and the like.

The coating composition of the present invention is combined with a coating composition for a clear coat containing both the carboxyl group-containing resin (f) and the epoxy group-containing resin (g) as described in detail above to form a base coat. In that case, a more excellent effect is exhibited.

The coating composition of the present invention comprises (A) a step of forming an undercoat on the article to be coated and, if necessary, an intermediate coating film,
(B) a step of applying a coating composition on the formed coating film, (C) without curing the applied coating composition, or after curing the applied coating composition ,
A step of applying a clear coat coating composition on this,
(D) a step of curing both the applied coating composition and the applied clear coating composition, or only the applied clear coating composition,
Can be painted by. The coating method of the present invention is
It can be applied to essentially any substrate, for example wood, metal,
On the surface of glass, cloth, plastic, foam, or
It can be applied to various primer surfaces, but is particularly suitable for plastic and metal surfaces. The film thickness can be set to a desired value depending on the application, but in most cases 10 to 50 μm
Is preferred. The coating method of the present invention may cure only the coating film of the base coating after coating, but without curing the base coating, further coating both coating films on the surface thereof after coating the coating composition for clear coat. Harden, so-called 2
The coat 1 bake coating method is preferably used. Curing of the coating film is 100 to 1 to obtain a cured coating film having a high crosslinking density.
It is carried out at 80 ° C, preferably 120 to 160 ° C. The curing time varies depending on the curing temperature, but is preferably 10 to 30 minutes in the range of 120 to 160 ° C.

The coating composition containing the thermosetting resin composition of the present invention as a binder component can be used by coating it on various coated objects. The article to be coated is not particularly limited as long as it can heat-cure the thermosetting resin composition, and examples thereof include automobile bodies; automobile parts such as wheels and bumpers; home electric appliances such as air conditioner outdoor units; Building materials such as outer wall materials can be mentioned.

[0087]

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. In the following, the blending amount is parts by weight (hereinafter, simply referred to as “part”).

Production Example 1 Ethylate containing long-chain carboxyl group
In a 2 L reaction vessel equipped with a thermosetting unsaturated monomer thermometer, a stirrer, a cooling tube, and a nitrogen introducing tube, Arcosolv PMA and the hydroxyl group-containing ethylenically unsaturated monomer and acid anhydride group-containing compound shown in Table 1 are shown. Charge with the compounding amount shown in 1 and take 15 minutes in about 30 minutes
The temperature was raised to around 0 ° C. and kept for 20 minutes. Then, it cooled and taken out from the reaction container, and the carboxyl group-containing ethylenically unsaturated monomer (Ai-A-vi) was obtained. In Table 1, HEA is hydroxyethyl acrylate, HEMA is hydroxyethyl methacrylate,
Praxel FA-1 and Praxel FM-1 are "Plaxel FA-1" and "Plaxel FM-1" manufactured by Daicel Chemical Industries Ltd., SAn is succinic anhydride, HHPA is hexahydrophthalic anhydride, and 4MHHPA is 4-methyl. Represents hexahydrophthalic anhydride.

Production Example 2 Reaction-promoting ethylenically unsaturated model
Toluene, n-butanol, and propylene glycol monomethyl ether were charged at a compounding amount shown in Table 2 into a 200 ml reaction vessel equipped with a nomer-containing thermosetting resin thermometer, a stirrer, a cooling tube, a nitrogen introducing tube, and a dropping funnel. The long-chain carboxyl group-containing ethylenically unsaturated monomer (Ai to A-vi) obtained in Production Example 1 and the reaction-promoting ethylenically unsaturated monomer (d-1 to d- 6) and Table 2
A solution containing the other monomer shown in Table 1 in a blending amount shown in Table 2 and containing 1.50 parts of t-butylperoxy-2-ethylhexanoate as an initiator was added dropwise over 3 hours, and then for 30 minutes. After holding at 110 ° C., 0.5 part of t-butylperoxy-2-ethylhexanoate, 1 part of toluene
2.69 parts were added dropwise over 30 minutes. Stirring is further continued for 90 minutes and cooled to 70 ° C. to obtain thermosetting resins (A-1 to A-6) containing a reaction-promoting ethylenically unsaturated monomer having a sulfonic acid group and a phosphoric acid group. It was Table 2 shows the nonvolatile content (%), number average molecular weight, acid value and hydroxyl value of the obtained resin composition.

[0090]

[Chemical 9]

Similarly, according to the formulation shown in Table 3, an acrylic resin containing no reaction-promoting ethylenically unsaturated monomer having a sulfonic acid group or a phosphoric acid group, which is a monomer containing a long-chain carboxylic acid, is used. And N, N'-
Not containing both dimethylacrylamide (B-
1 to B-6), and N, N'-dimethylacrylamide-containing resin containing a long-chain carboxylic acid and having a sulfonic acid group and a phosphoric acid group, the reaction promoting ethylenic The thing (C-1 to C-3) which does not contain an unsaturated monomer was obtained. The nonvolatile content (%), number average molecular weight, acid value and hydroxyl value of the obtained resin composition are also shown in Tables 3 and 4.

Production Example 3 Clear Coating Clear Coating (I) 58.3 parts of DIANAL HR-554 (thermosetting acrylic resin varnish manufactured by Mitsubishi Rayon Co., solid content 60%), AC
R-461 (Nippon Paint Co., Ltd. thermosetting acrylic resin varnish, solid content 55%) 63.6 parts, U-Van 20N-6
0 (Mitsui Toatsu Chemicals, melamine resin) 50.0 parts, Tinuvin 900 (Ciba-Geigy ultraviolet absorber) 2.0
Part, Sanol LS-292 (antioxidant manufactured by Sankyo Machine Gosei Co., Ltd.) 1.0 part, n-butanol 1.3 part, Solvesso 1
It was prepared by mixing 5.0 parts (solvent) of 00 (manufactured by Esso Corporation).

Clear coating (II) A 1-liter reaction vessel equipped with a thermometer, a stirrer, a cooling tube and a nitrogen introducing tube was charged with 400 parts of trimethylolpropane, 130 parts of xylene and 123 parts of hexahydrophthalic anhydride, at 130 ° C. Polymer (a) having a carboxyl group was obtained by stirring for 60 minutes. On the other hand, a thermometer,
A 2 liter reaction vessel equipped with a stirrer, a cooling tube, a nitrogen introducing tube, and a dropping funnel was charged with 500 parts of butyl acetate.
The temperature was raised to 25 ° C. 50 parts of styrene, 400 parts of glycidyl methacrylate, 35 parts of butyl methacrylate in a dropping funnel.
0 part, 2-ethylhexyl acrylate 200 parts and t-
A monomer and initiator solution solution consisting of 70 parts of butylperoxy 2-ethylhexanoate was added dropwise over 3 hours. After the dropping was completed, the mixture was kept at 125 ° C. for 30 minutes, then 10 parts of t-butylperoxy 2-ethylhexanoate and xylene 2
A solution of 50 parts was added dropwise over 30 minutes. After the completion of the dropping, the reaction was continued at 125 ° C. for another 2 hours, and the non-volatile content was 59% by weight, the number average molecular weight was 4000, and the epoxy equivalent was 35.
A polymer (b) having an epoxy group of 5 was obtained. 200 parts of the polymer (a), 140 parts of the polymer (b),
Tetrabutylammonium bromide 0.3 part, tetrabutylammonium salicylate 0.6 part, magnesium dodecylbenzene sulfonate 1.0 part, tinuvin 90
0 (UV absorber manufactured by Ciba Geigy) and 2.0 parts of TINUVIN 123 (UV absorber manufactured by Ciba Geigy) were mixed and prepared.

Clear coating (III) A 1-liter reaction vessel equipped with a thermometer, a stirrer, a cooling tube, a nitrogen introducing tube, and a dropping funnel was charged with 80 parts of xylene, heated to 115 ° C., and 25 parts of styrene and acryl. Acid n
-Butyl 21 parts, n-butyl methacrylate 95 parts, 2-ethylhexyl methacrylate 34 parts, maleic anhydride 5
3 parts of a monomer and initiator solution consisting of 0 part, 100 parts of propylene glycol monomethyl ether acetate and 10 parts of t-butylperoxy 2-ethylhexanoate.
It is added dropwise over a period of time, and the stirring is continued for another 2 hours.
A polymer (c) having an acid anhydride group having a weight percentage of 5500 and a number average molecular weight of 5,500 was obtained. 415 of the obtained polymer (C)
24.5 parts of methanol was added to the mixture, and the mixture was reacted at 65 ° C. for 24 hours to obtain a polymer (d) having a carboxyl group and a carboxylic acid ester group.

On the other hand, 450 parts of xylene and 50 parts of n-butanol were charged into a 2 liter reaction vessel equipped with a thermometer, a stirrer, a cooling tube, a nitrogen introducing tube, and a dropping funnel, and a temperature of 125
The temperature was raised to ° C. 220 parts of styrene, 320 parts of glycidyl methacrylate, 220 parts of 4-hydroxybutyl methacrylate, 24-ethylhexyl acrylate are added to the dropping funnel.
A monomer and initiator solution consisting of 0 part and 50 parts of t-butylperoxy 2-ethylhexanoate was added dropwise over 3 hours. After maintaining at 125 ° C. for 30 minutes after completion of dropping, t
A solution consisting of 10 parts of -butylperoxy 2-ethylhexanoate and 250 parts of xylene was added dropwise over 30 minutes. After the dropwise addition was completed, the reaction was continued at 125 ° C. for another 2 hours to obtain a polymer (e) having a hydroxyl group and an epoxy group having a number average molecular weight of 7,000, an epoxy equivalent of 444 and a hydroxy equivalent of 650. 200 parts of the polymer (d), 180 parts of the polymer (e), 0.3 part of tetrabutylammonium bromide, 0.6 part of tetrabutylammonium salicylate, 1.0 part of magnesium dodecylbenzene sulfonate, Tinuvin 900 (Ciba Geigy) 2.0 parts by weight of UV absorber) and 1.0 part of TINUVIN 123 (UV absorber by Ciba Geigy) were prepared.

Examples 1 to 6 and Comparative Examples 1 to 4 Using the formulations shown in Table 5, ethyl acetate, Uban 128 (Melamine resin manufactured by Mitsui Toatsu Chemicals, Inc.), Uban 20N60.
(Mitsui Toatsu Chemical Co., Ltd., melamine resin), Uban 225
(Mitsui Toatsu Chemicals, melamine resin), Alpaste 7
160N (manufactured by Toyo Aluminum Co., Ltd.), polymers A-1 to A-6, polymers B-1 to B-6, and polymer C obtained in Production Example 2
-1 to C-3, Tinuvin 900 (manufactured by Ciba Geigy) as an ultraviolet absorber, Sanol LS-292 (manufactured by Ciba Geigy), and n-butanol were mixed in the above order while stirring with a disper to prepare a silver base paint. did. In Example 5, 5 parts of cyanine blue G314 (color pigment made by Sanyo Dye Co., Ltd.) was added to the polymer (B-5) 58.
Part, after carrying out pigment dispersion using a desk SG mill,
Other ingredients were blended. In addition, in Example 6, 10 parts of cyanine blue G314 (manufactured by Sanyo Dye Co., Ltd., coloring pigment) was dispersed in 58 parts of the polymer (B-6) using a desktop SG mill, and then other components were added. Was compounded. For Comparative Example 4, in addition to the components shown in Table 5, 3.2 parts of paratoluenesulfonic acid as a catalyst was further added.

Cation electro-deposition coating (Power Top U-50 manufactured by Nippon Paint Co., Ltd.) was electro-deposited on a zinc phosphate treated 0.8 mm thick dull steel plate to a dry film thickness of about 25 μm. It was baked at 30 ° C. for 30 minutes. An intermediate coating composition (Olga P-2 manufactured by Nippon Paint Co., Ltd.) was spray-coated on the obtained electrodeposition coating film so that the dry film thickness was about 40 μm, and baked at 140 ° C. for 30 minutes to obtain an intermediate coating composition. I got a coated plate. After cooling, the base coating of each of the examples and comparative examples listed in Table 5 was spray-coated on the obtained coated intermediate coating plate so that the dry film thickness was about 16 μm and set for about 7 minutes.

Next, the clear paint (I), the clear paint (II) or the clear paint (II) obtained in Production Example 3 was used.
I) to Ford Cup No. The viscosity was adjusted to 4 seconds for 20 seconds, and the dry film thickness was about 40 at an atomizing pressure of 5 kg / cm ² using an electrostatic coating machine Auto REA (manufactured by Randsburg Gemma).
Paint to a thickness of μm, set for about 7 minutes, and then 1
The top coated plate was prepared by baking at 40 ° C. for 25 minutes.
Under the same conditions, the baking temperature was set to 120 ° C,
A top coated plate was prepared. For each of the examples and comparative examples, two types of clear paints shown in Table 5 were used.

Evaluation of Coating Film Performance The following performance evaluation was carried out on the obtained top coated plate. 1. Chipping resistance Gravelo tester (stepping stone tester; manufactured by Suga Test Instruments Co., Ltd.) was cooled to -20 ° C at the baking temperature of 140 ° C in the holder, and the stone entry angle was changed to 45 °. The crushed stone was made to collide with the coating film under the following conditions. Size of stone: No. 7 crushed stone (according to JIS A 5001) Amount of stone: 50 g Air pressure to blow stone: 4.0 kg / cm ² Distance from stone exit to coating film: 35 cm Test temperature: -20 ° C Stone Angle of entry: 45 degrees The degree of peeling scratches upon collision was visually observed. The evaluation was performed according to the following criteria, and the results are shown in Table 5. ◯: No peeling at all. B: Slightly small shallow peeling is recognized. X: There is peeling.

2. Water resistance Each test piece of the top coated plate obtained at a baking temperature of 140 ° C. and the top coated plate obtained at a baking temperature of 120 ° C. was immersed in warm water of 40 ° C. and left for 10 days,
The coating film state of the test piece was visually observed. The evaluation was performed according to the following criteria, and the results are shown in Table 5. ◯: No change is observed. Δ: Traces are slightly seen. X: Abnormality is seen in the coating film.

3. Solvent resistance The top coated plate obtained at a baking temperature of 140 ° C. and the top coated plate obtained at a baking temperature of 120 ° C. were used as test pieces after a lapse of 24 hours. Next, put a mixed solvent of toluene / n-hexane = 1/9 in a glass container up to a depth of about 90 mm, keep it at room temperature, and hang the test piece in it with a clip and a string to a depth of about 80 mm. It was soaked, left for 24 hours, taken out, wiped off the lubricating oil with absorbent cotton, and after 2 hours, the coated surface was visually observed. The evaluation criteria are as follows. The results are shown in Table 5. ◯: No blistering or peeling was observed on the coated surface, and clouding or softening was not remarkable. Δ: Slightly cloudy and softening is observed. X: Abnormality is recognized.

[0102]

[Table 1]

[0103]

[Table 2]

[0104]

[Table 3]

[0105]

[Table 4]

[0106]

[Table 5]

From the examples, the coating film using the coating composition of the present invention does not lower the curability even when baked at a low temperature of 120 ° C. or 140 ° C., and the half-esterified copolymer It was found that even in the case of using a combination and a clear coating containing a polymer containing both an epoxy group and a hydroxyl group, the chipping resistance, water resistance and solvent resistance are excellent. On the other hand, when an external catalyst was used, the chipping resistance and the water resistance were clearly reduced.

[0108]

The resin composition of the present invention uses a reaction-accelerating ethylenically unsaturated monomer, and therefore has excellent curability. In particular, the curability does not deteriorate even in low temperature baking. According to the present invention, even if a clear coating for forming a coating film having a high degree of crosslinking using a polyfunctional resin is applied thereon, it is excellent in chipping resistance, water resistance, solvent resistance and has a high quality appearance. A base coat coating composition for two coats and one bake capable of forming a metallic coating film to be presented can be provided.

Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical display location C09D 133/26 PFW C09D 133/26 PFW (72) Inventor Yoshitaka Okude 19-17 Ikedanaka-cho, Neyagawa-shi, Osaka Within Japan Paint Co., Ltd.

Claims (8)

[Claims] 1. A dialkylamide group-containing ethylenically unsaturated monomer (a) 1 to 50% by weight, a long-chain carboxyl group-containing ethylenically unsaturated monomer (b) 1 to 65% by weight,
Hydroxyl group-containing ethylenically unsaturated monomer (c) 2 to 70% by weight, reaction-promoting ethylenically unsaturated monomer (d) 0.
A composition obtained by copolymerizing 1 to 50% by weight and an appropriate amount of another copolymerizable ethylenically unsaturated monomer (e), wherein the hydroxyl value is 10 to 300 and the acid value is 2 to 100, number average molecular weight 500-50000, The thermosetting resin composition characterized by the above-mentioned. 2. The dialkylamide group-containing ethylenically unsaturated monomer (a) comprises N, N′-dimethylacrylamide group, N, N′-dimethylmethacrylamide group, N,
The thermosetting resin composition according to claim 1, which is an ethylenically unsaturated monomer containing at least one selected from the group consisting of N'-dibutylacrylamide group and N, N'-dibutylmethacrylamide group. 3. The long-chain carboxyl group-containing ethylenically unsaturated monomer (b) comprises a hydroxylalkyl (meth) acrylate and an acid anhydride as (moles of acid anhydride group) /
(Number of moles of hydroxyl group) = 0.5 / 1.0 to 1.0 / 1.0
The thermosetting resin composition according to claim 1, which is obtained by reacting in a ratio such that 4. The reaction-accelerating ethylenically unsaturated monomer (d) is at least one selected from the group consisting of sulfonic acid group-containing ethylenically unsaturated monomers and phosphoric acid group-containing ethylenically unsaturated monomers. Item 1. A thermosetting resin composition according to item 1. 5. A coating composition comprising the thermosetting resin composition according to claim 1, 2, 3 or 4 as a binder component. 6. A coating composition according to claim 5, wherein (A) a step of forming an undercoat on the article to be coated and optionally an intermediate coating film, and (B) the formed coating film. Process,
(C) a step of coating the coating composition for clear coat thereon, without curing the coating composition applied, or after curing the coating composition applied,
(A), (B), (of the step of curing both the applied coating composition and the applied coating composition for clear coat, or only the applied coating composition for clear coat. A coating method comprising C) and (D). 7. A coated article obtained by coating the coating composition according to claim 5. 8. A coated article coated by the coating method according to claim 6.