JPH0665791A - Formation of coating film - Google Patents

Abstract

PURPOSE:To form a double-layered coating film capable of shortening the coating process and excellent in finishing properties of edge-covering and chipping. CONSTITUTION:On the uncurred coated surface which is applied by cation electrodeposition coating, a chipping resistant primer is applied and further an intercoat or a topcoat is applied, and the three-layered film is cured simultaneously and a plural-layered coated film is formed. In this time, the reduction weight of this due to removed of the moisture cation electrodeposited film should be <=10wt.% on heat-curing, and the film obtained from the cation electrodeposition coating should have 10<4>-10<8>cps minimal melting viscosity on curing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention applies a cationic electrodeposition coating, a chipping-resistant primer, an intermediate coating or a direct top coating by wet-on-wet, and then simultaneously heats the three-layer coating so-called 3 The present invention relates to a method for forming a multilayer coating film by a coat 1 bake method.

[0002]

2. Description of the Related Art Conventionally, in the case of outer panels of automobiles, a cationic electrodeposition coating is electrodeposition-coated and heat-cured, and then an intermediate coating or top coating is applied on the coated surface.
It is often cured by heating. Further, particularly in the coating system for steel plate parts of automobile bodies, a chipping-resistant primer layer is further provided between the electrodeposition coating film and the intermediate coating or top coating film for the purpose of improving chipping resistance and corrosion resistance of the end face portion. .

In recent years, from the viewpoint of shortening the coating process, saving resources and preventing pollution, a cationic electrodeposition coating film is coated with a chipping-resistant primer and / or an intermediate coating or a top coating composition on the coated surface without heat curing. After that, a two-coat one-bake system in which these coating films are simultaneously cured by heating,
Furthermore, there is a strong demand for the development of a coating film forming method using a three-coat one-bake system. However, such wet-on-wet coating makes it possible to evaporate a basic substance or a low amount of basic substance that volatilizes from the uncured cationic electrodeposition coating film when heated. A large amount of molecular substance migrates to the upper coating film by a chipping-resistant primer or an intermediate coating or a top coating material, and bleeding, curing inhibition, etc. occur, and the smoothness and sharpness of the coating film, and further the chipping resistance, etc. There are problems such as insufficient performance, and it has not yet been put to practical use.

Further, although the cationic electrodeposition coating is excellent in throwing power and film thickness uniformity, the coating film thickness at the edge portion of the article to be coated does not become thick when heated, resulting in insufficient edge coverability. However, even if a multilayer coating film as described above is formed, there is a problem in edge corrosion resistance.

[0005]

According to the present invention, three coats of a cationic electrodeposition coating, a chipping-resistant primer, and an intermediate coating or a top coating are produced without the above-mentioned problems.
With the aim of improving the edge cover property by coating with a baking method to form a multi-layer coating film having excellent finishing properties, chipping resistance, etc.
The present invention has been completed by finding that the purpose can be achieved by using a specific cationic electrodeposition coating composition.

That is, according to the present invention, an uncured coating film surface coated with a cationic electrodeposition coating composition is coated with a chipping-resistant primer, and then an intermediate coating composition or a top coating composition is coated, and the three-layer coating film is simultaneously cured. A method of forming a multilayer coating film by the method, wherein the cationic electrodeposition coating composition is a coating composition in which the weight loss of the coating composition upon heat curing of the electrodeposition coating composition from which water is removed is 10% by weight or less, and The minimum melt viscosity of the coating film obtained from the cationic electrodeposition coating upon curing is 10 ⁴ to 10 ⁸ cp.
The present invention provides a method for forming a coating film characterized by being s.

The paint used in the present invention and the method for forming a coating film using the same will be described below.

First, a cationic electrodeposition paint used in the method of the present invention (hereinafter, may be abbreviated as "paint (A)").
Has a coating weight loss of 10% by weight when the electrodeposition coating film is cured by heating.
It is necessary that the content be below, particularly preferably 7% by weight or less. If it exceeds 10% by weight, the smoothness and sharpness of the coating film surface due to the coating material coated on the coating surface are deteriorated, which is not preferable.

In the present invention, the coating weight loss (X) when the electrodeposition coating film of the coating material (A) is heated and cured is first subjected to cationic electrodeposition coating under normal conditions and then pulled out from the electrodeposition bath to obtain a coated surface. Was washed with water and heated at 105 ° C. for 3 hours to remove all or most of the water in the coating film, and then the coating film weight (Y) was measured, and then the coating film was heated at 170 ° C. for 20 minutes to form the coating film. The coating film weight (Z) after the three-dimensional crosslinking and curing was measured. These measured values were applied to the following formula to determine the coating film weight loss (X).

[Equation 1]

The paint (A) has a minimum melt viscosity of 10 ⁴ to 10 ⁸ cp when the coating film obtained from the paint is cured.
It is necessary to be within the range of s from the viewpoint of edge covering property.

In the present invention, the minimum melt viscosity means the minimum value when the viscosity of the coating film once becomes smaller than the initial value in the process of curing the coating film by baking.
The viscosity of the coating film then increases sharply. The minimum melt viscosity is determined from the heat-fluid appearance of scratches in comparison with a paste having a known viscosity according to the rolling ball type viscosity measuring method in JIS-Z-0237.

The paint (A) has a coating weight loss of 1 when cured by heating.
It is not particularly limited as long as it is a cationic electrodeposition coating composition of 0% by weight or less, preferably 7% by weight or less, and the minimum melt viscosity at the time of curing the coating film is in the range of 10 ⁴ to 10 ⁸ cps. The condition of the coating weight loss at the time of heat curing is satisfied,
The cationic electrodeposition coatings (A-1) and (A-2) containing the following resin components as the main components are preferable, and the coating composition melt viscosity can be improved by adding particulate components such as gelled fine particles and pigments to these coatings. Can be adjusted within the above range.

First, a resin (I) containing a hydroxyl group and a cationic group as the coating material (A-1); an epoxy group-containing function obtained by bonding an epoxy group to an alicyclic skeleton and / or a bridged alicyclic skeleton. A cationic electrodeposition coating composition containing as a main component an epoxy resin (II) having an average of 2 or more groups per molecule is mentioned.

The electrodeposition coating film formed by using the coating composition (A-1) cures at a temperature of about 250 ° C. or lower. And especially
Approximately 70 ° C when compounding one or more compounds containing metals such as lead, zirconium, cobalt, aluminum, manganese, copper, zinc, iron, chromium and nickel as a catalyst
It can be cured by heating at a low temperature of about 160 ° C. Upon curing, the epoxy group contained in the epoxy resin (II) is ring-opened and reacts with the hydroxyl group (preferably primary one) in the resin (I), and further, in the resin (II). It is presumed that the epoxy groups react with each other to form ether bonds to crosslink and cure, and byproducts are hardly generated during the curing reaction, and the coating film weight is extremely small.

Therefore, the coating material (A-1) can be prepared without using a tin catalyst which is usually used as a curing catalyst for electrodeposition coating materials.
Can be cured at a low temperature of 0 ° C. or lower; further, it is not necessary to use a blocked isocyanate compound or its derivative; heat loss due to thermal decomposition (volume shrinkage) is small and good adhesion is exhibited; aroma during cross-linking It does not bring in a group urethane bond or an aromatic urea bond; the electrodeposition coating film has excellent anticorrosion properties and curability; the stability of the electrodeposition bath is good; and other various advantages.

The resin (I) having a hydroxyl group and a cationic group used in the coating material (A-1) (hereinafter this may be referred to as "base resin (I)") includes the epoxy of the component (II). Any resin containing hydroxyl groups capable of reacting with the groups and having a sufficient number of cationic groups to form a stable aqueous dispersion is included. Then, as the base resin (I), for example, the following may be mentioned.

(I) A reaction product obtained by reacting a polyepoxy resin with a cationizing agent; (ii) a polycondensate of a polycarboxylic acid and a polyamine (see US Pat. No. 2,450,940). ) Is protonated with an acid; (iii) Polyisocyanate and a polyaddition product of a polyol with a mono- or polyamine are protonated with an acid; (iv) Copolymerization of a hydroxyl group- and amino group-containing acrylic or vinyl-based monomer Those obtained by protonating the coalescence with an acid (Japanese Patent Publication No. 45-12395, Japanese Patent Publication No. 45-12396).
(V) A product obtained by protonating an adduct of a polycarboxylic acid resin and an alkyleneimine with an acid (US Pat. No. 3,403,
No. 088); etc.

Specific examples and production methods of these cationic resins are described in, for example, JP-B-45-12395, JP-B-45-12396, and JP-B-49-23.
087, US Pat. No. 2,450,940, US Pat. No. 3,403,088, US Pat. No. 3,891,529, US Pat.
Since it is described in the specification of No. 3,663, etc., the detailed description will be replaced with these citations.

Particularly desirable as the base resin (I) is
A reactive product obtained by reacting a cationizing agent with an epoxy group of a polyepoxy compound having excellent anticorrosion properties obtained from a polyphenol compound and epichlorohydrin included in the above (i).

The polyepoxide compound is a compound having two or more epoxy groups in one molecule, and generally has a number average molecular weight in the range of at least 200, preferably 400 to 4,000, more preferably 800 to 2,000. Those that have are suitable. As such a polyepoxide compound, one known per se can be used,
For example, a polyglycidyl ether of a polyphenol compound which can be produced by reacting a polyphenol compound with epichlorohydrin in the presence of an alkali is included. Examples of the polyphenol compound that can be used here include bis (4-hydroxyphenyl)
-2,2-propane, 4,4'-dihydroxybenzophenone, bis (4-hydroxyphenyl) -1,1-ethane, bis- (4-hydroxyphenyl) -1,1-isobutane, bis (4-hydroxy-) tert-butyl-
Phenyl) -2,2-propane, bis (2-hydroxynaphthyl) methane, 1,5-dihydroxynaphthalene,
Bis (2,4-dihydroxyphenyl) methane, tetra (4-hydroxyphenyl) -1,1,2,2-ethane, 4,4'-dihydroxydiphenyl ether, 4,
4′-dihydroxydiphenyl sulfone, phenol novolac, cresol novolac and the like can be mentioned.

Among the polyepoxide compounds mentioned above, those particularly suitable for the production of the base resin (I) have a number average molecular weight of at least about 380, more preferably from about 800 to about 2.
000, and an epoxy equivalent of 190 to 2,000, preferably 400 to 1,000, which is a polyglycidyl ether of a polyphenol compound, particularly the following formula:

[Chemical 1] It is shown by. The polyepoxide compound may be partially reacted with a polyol, a polyether polyol, a polyester polyol, a polyamidoamine, a polycarboxylic acid, a polyisocyanate, and the like.
You may graft-polymerize delta-4 caprolactone, an acrylic monomer, etc.

On the other hand, as a cationizing agent for introducing a cationic group into the above polyepoxide compound, an aliphatic, alicyclic or aromatic-aliphatic primary or secondary agent is used.
Tertiary amine, tertiary amine salt, secondary sulfide salt, tertiary
Grade phosphine salts and the like. These react with the epoxy groups to form cationic groups. Further, the tertiary aminomonoisocyanate obtained by the reaction of the tertiary amino alcohol and diisocyanate can be reacted with the hydroxyl group of the epoxy resin to form a cationic group.

Examples of the amine compound in the cationizing agent include the following. (1) Primary amines such as ethylamine, n- or iso-propylamine, monoethanolamine, n- or iso-propanolamine; (2) Secondary amines such as diethylamine, diethanolamine, N-methylethanolamine; (3) Polyamines such as ethylenediamine, diethylenetriamine, hydroxyethylaminoethylamine, ethylaminoethylamine and dimethylaminoethylamine.

Of these, alkanolamines having a hydroxyl group are preferable. Alternatively, the primary amino group may be reacted with the ketone in advance to block it, and then the remaining active hydrogen may be reacted with the epoxy group.

Further, in addition to the above amine compounds, basic compounds such as ammonia, hydroxylamine, hydrazine, hydroxyethylhydrazine and N-hydroxyethylimidazoline compounds can be similarly used.
The basic group formed using these compounds can be protonated with an acid, particularly preferably a water-soluble organic carboxylic acid such as formic acid, acetic acid, glycolic acid or lactic acid to form a cationic group.

Further, tertiary amines such as triethylamine, triethanolamine, N, N-dimethylethanolamine, N-methyldiethanolamine, N, N-diethylethanolamine and N-ethyldiethanolamine can also be used, and these are acid. Previously protonated with
It can be reacted with epoxy groups to form quaternary salts.

In addition to amino compounds, sulfides such as diethyl sulfide, diphenyl sulfide, tetramethylene sulfide, thiodiethanol and boric acid,
A tertiary sulfonium salt may be obtained by reacting a salt with carbonic acid, an organic monocarboxylic acid or the like with an epoxy group.

Furthermore, a salt of a phosphine such as triethylphosphine, phenyldimethylphosphine, diphenylmethylphosphine, and triphenylphosphine with an acid as described above may be reacted with an epoxy group to form a quaternary phosphonium salt.

The hydroxyl group of the base resin (I) is, for example, an alkanolamine in the above cationizing agent, a caprolactone ring-opened product which may be introduced into an epoxide compound, or a primary hydroxyl group which can be introduced from a polyol or the like; Secondary hydroxyl group in the epoxy resin; and the like.
Of these, the primary hydroxyl group introduced by the alkanolamine is preferable because it has excellent crosslinking and curing reactivity with the epoxy resin (II). Such alkanolamines are preferably those exemplified as the cationizing agent.

The content of hydroxyl groups in the base resin (I) is 20 to 5,000 in terms of hydroxyl group equivalents in terms of crosslinking and curing reactivity with the epoxy groups contained in the epoxy resin (II).
0, particularly preferably in the range of 100 to 1,000, and particularly preferably the primary hydroxyl group equivalent is in the range of 200 to 1,000. In addition, the content of the cationic group is preferably at least the minimum necessary to stably disperse the base resin (I), and is generally 3 to 200 in terms of KOH (mg / g solid content) (amine value), particularly preferably It is preferably in the range of 10 to 80. However, even when the content of the cationic group is 3 or less, it is also possible to use it as an aqueous dispersion by using a surfactant or the like. In this case, the pH of the aqueous dispersion composition is Is usually 4 to 9, and more preferably 6 to 7.
It is desirable to adjust the cationic group so that

The base resin (I) has a hydroxyl group and a cationic group, and as a general rule, it is desirable not to include a free epoxy group.

Next, the epoxy resin (II) as a curing agent used by mixing with the base resin (I) will be described.

The epoxy resin (II) (hereinafter sometimes referred to as "curing resin (II)") forms a crosslinked cured coating film with the base resin (I) mainly through the etherification reaction as described above. A curing agent for the purpose of having an average of 2 or more, preferably 3 or more, specific "epoxy group-containing functional groups" per molecule.

That is, the epoxy group-containing functional group in the curable resin (II) is composed of an alicyclic skeleton and / or a bridged alicyclic skeleton and an epoxy group, and the alicyclic skeleton is 4
A saturated carbocyclic ring of 10 to 10 members, preferably 5 to 6 members, or a condensed ring in which two or more of the rings are condensed, and the bridged alicyclic skeleton has the above-mentioned cyclic or polycyclic ring. A linear or branched C _1-6 (preferably C _1-4 ) alkylene group between two constituent carbon atoms [eg, —CH ₂ —, —CH
_{2 -CH 2 -, - CH (} CH 3) -, - CH 2 (CH
_{3) CH 2 -, - C} (CH 3) 2 -, - CH (C 2 H
₅ ) CH ₂ —, etc.] bridges (endmethylene, endoethylene, etc.) are contained.

On the other hand, in the epoxy group, one of carbon atoms in the epoxy group is directly bonded to a ring carbon atom in the alicyclic skeleton or the bridged alicyclic skeleton [for example, the following formula (a): , (B)], or two carbon atoms of the epoxy group and two adjacent carbon atoms forming the ring in the alicyclic skeleton or the bridged alicyclic skeleton are common. [For example, see the following formulas (c) and (d)] is important.

Specific examples of such an epoxy group-containing functional group include those represented by the following formulas (A) to (D).

[Chemical 2]

[Chemical 3]

[Chemical 4]

[Chemical 5] (In the formula, R ₁ , R ₂ , R ₃ , R ₅ , R ₆ , R ₇ , R ₁₀ and R ₁₁ each represent H, CH ₃ or C ₂ H ₅ ,
R ₄ , R ₈ and R ₉ each represent H or CH ₃ . )

The epoxy resin (II) is represented by the above formula (A) to
An average of at least 2, preferably 2 or more, and more preferably 4 or more epoxy group-containing functional groups selected from (d) can be contained in one molecule.
Or at least one epoxy group-containing functional group represented by (b), or at least one epoxy group-containing functional group represented by the above formula (c) or (d).
You can have seeds. Furthermore, epoxy resin (I
I) is a molecule in which at least one kind of the epoxy group-containing functional group represented by the formula (a) or (b) and at least one kind of the epoxy group-containing functional group represented by the formula (c) or (d) are the same molecule. It can also be within or in a different molecule.

Of the above, the epoxy group-containing groups represented by the formulas (a) and (c) are preferable, and in particular the following formula (e)

[Chemical 6] An epoxy group-containing functional group represented by, and the following formula (f)

[Chemical 7] An epoxy group-containing functional group represented by is preferable.

The epoxy equivalent and molecular weight of the epoxy resin (II) are not strictly limited and can be changed according to the production method thereof and the intended use of the final resin composition. For example, the epoxy equivalent is usually 10
It can be in the range of 0 to 2,000, preferably 150 to 500, more preferably 150 to 250, and the number average molecular weight is usually 400 to 100,000, preferably 700 to 50,000, and more preferably Is 700
Suitably it is in the range of ˜30,000.

Epoxy resin having two or more such epoxy group-containing functional groups in one molecule [curing resin (II)]
Are disclosed, for example, in Japanese Patent Publication No. Sho 56-8016 and Japanese Patent Laid-Open No.
-47365, JP-A-60-166675, JP-A-63-221121, and JP-A-63-2.
It is described in documents such as 34028, and those known per se can be used.

Alternatively, the epoxy resin (II) having an epoxy group-containing functional group can be obtained by a method known per se, and the main production methods thereof are listed below, but the invention is not limited thereto.

First Production Method: Part of the double bond of the alicyclic compound having two or more carbon-carbon double bonds in one molecule is partially epoxidized, and the epoxy group is subjected to ring-opening polymerization, A method of epoxidizing the double bond remaining in a polymer.

Second production method: a method in which an alicyclic compound having two or more epoxy groups in the same molecule is subjected to ring-opening polymerization based on the epoxy groups to the extent that all of the epoxy groups are not erased.

Third production method: a method of polymerizing a compound having an epoxy group-containing functional group and a polymerizable unsaturated bond in the same molecule.

Hereinafter, these manufacturing methods will be described more specifically.

First production method : One of the double bonds contained in an alicyclic compound having two or more carbon-carbon double bonds in one molecule (hereinafter abbreviated as "alicyclic compound (S)") After partially epoxidizing (partially epoxidized product) and then ring-opening polymerization of the epoxy group to obtain a ring-opening polymer of the partially epoxidized product, part or all of the double bond remaining in the polymer is obtained. The curable resin (II) is obtained by epoxidizing.

The alicyclic compound (S) has the alicyclic ring or bridged alicyclic ring structure described above for the alicyclic skeleton or bridged alicyclic skeleton as a base skeleton, and further has a double bond and a ring. It is a compound which exists between two adjacent carbon atoms constituting the compound or which contains at least two carbon atoms constituting the ring structure in a state where a double bond based on another carbon atom is directly bonded.

The alicyclic compound (S) can also be obtained, for example, by heating a conjugated diene compound based on a known method. As the conjugated diene compound, an aliphatic or alicyclic compound having 4 to 30 carbon atoms, which has one or more pairs, preferably 1 to 5 pairs of double bonds having a conjugated relationship in one molecule, is suitable. Include butadiene, isoprene, pyrylene,
1,3-hexadiene, 2,4-hexadiene, 2-methyl-6-methylene-2,7-octadiene, cyclopentadiene, cyclohexadiene, 4-ethyl-2-methylcyclopentadiene, 3-isopropyl-1-methylcyclo Pentadiene, 5-isopropylcyclopentadiene, 1,4-diphenylcyclopentadiene, hexachlorocyclopentadiene, 5,5-diethoxy-
1,2,3,4-tetrachlorocyclopentadiene,
1,2,3,4-tetrachlorocyclopentadiene,
1,3-cyclopentadiene, 1,3-cyclooctadiene, 1,3,5-cyclooctatriene, cyclooctatetraene, 5-cyclohexylidenecyclopentadiene, etc., which may be used alone or in combination of two kinds. The above can be used in combination.

The alicyclic compound (S) is obtained by reacting the conjugated diene compound under heating with a Ziegler catalyst if necessary. This heating reaction can be carried out by a method known per se, for example, JP-A-49-10264.
The method disclosed in Japanese Patent Publication No. 3 can be used. Typical examples of the alicyclic compound (S) thus obtained are as follows.

[0050]

[Chemical 8]

Among the above conjugated diene compounds, compounds having an alicyclic structure such as cyclopentadiene, cyclohexadiene and 4-ethyl-2-methylcyclopentadiene, silbestrene, 2,8 (9) -p-menthadiene, Pyronene, 1,3-dimethyl-1-ethyl-3,5
-Cyclohexadiene, terpinene, ferrandrene,
Since dipentene, isolimonene, limonene and the like already have the structure of the alicyclic compound (S), they can be used as they are without being subjected to the above thermal reaction.

First, carbon contained in the alicyclic compound (S)
A part of the carbon double bond is modified into an epoxy group with a peroxide or the like (partial epoxidation). The partially epoxidized product is
A part of the plurality of double bonds contained in the alicyclic compound (S) is modified with an epoxy group, and specific examples thereof are as follows.

[0053]

[Chemical 9]

Naturally obtained epoxycalene and the like can also be used as the partial epoxidized product.

[Chemical 10]

The partially epoxidized product has at least one epoxy group and at least one carbon-carbon double bond in one molecule, and the double bond is between two adjacent carbon atoms constituting a ring. It must be present or have a carbon atom in the ring bonded to a double bond based on another carbon atom.

Next, ring-opening polymerization is carried out based on the epoxy group in the partially epoxidized product to obtain a polymer of alicyclic compound (S). It is preferable to use an initiator for this ring-opening polymerization, and the residue X due to the initiator component may be bonded to the terminal of the curing resin (II) which is the final product. Here, X is an organic compound residue having active hydrogen, and examples of the organic compound having active hydrogen as a precursor thereof include alcohols, phenols, carboxylic acids, amines,
Examples include thiols. Among them, the alcohol may be either a monohydric alcohol or a polyhydric alcohol having a valence of 2 or more, and specific examples thereof include aliphatic monohydric alcohols such as ethanol, propanol, butanol, hexanol, and octanol; Aromatic monohydric alcohols such as benzyl alcohol; ethylene glycol,
Diethylene glycol, polyethylene glycol, propylene glycol, 1,4-butanediol, 1,6-
Hexanediol, neopentyl glycol, oxybivalic acid neopentyl glycol ester, glycerin, trimethylolpropane, trimethylolethane,
Examples are polyhydric alcohols such as pentaerythritol and dipentaerythritol.

Examples of the phenols include phenol, cresol, catechol, pyrogallol, hydroquinone, hydroquinone monomethyl ether, bisphenol A, bisphenol F, 4,4'-dihydroxybenzophenone, bisphenol S, phenol resin,
Examples include cresol novolac resin.

As the carboxylic acids, formic acid, acetic acid, propionic acid, butyric acid, fatty acids of animal and vegetable oils; fumaric acid, maleic acid, adipic acid, dodecane diacid, trimellitic acid, pyromellitic acid, polyacrylic acid, phthalic acid, Examples thereof include isophthalic acid and terephthalic acid, and compounds having both a hydroxyl group and a carboxylic acid such as lactic acid, citric acid and oxycaproic acid can also be used.

Further, as other compounds having active hydrogen, a mixture of water and an alkoxysilane such as tetramethyl silicate, methyltrimethoxysilane, methyltriethoxysilane, phenyltrimethoxysilane, etc. or silanol compounds thereof, polyvinyl alcohol, poly Partial hydrolyzate of vinyl acetate, starch, cellulose, cellulose acetate, cellulose acetate butyrate,
Hydroxyethyl cellulose, acrylic polyol resin, styrene-allyl alcohol copolymer resin, styrene-maleic acid copolymer resin, alkyd resin, polyester polyol resin, polycaprolactone polyol resin and the like can also be used. Further, it may have an unsaturated double bond together with active hydrogen, and the unsaturated double bond may be epoxidized. Further, the catalyst and the initiator may be the same, such as an alkoxy metal compound.

Usually, using the organic compound having active hydrogen as an initiator, the partial epoxidized product such as 4-vinylcyclohexene-1-oxide, 4-vinylcyclo [2,2,1] 3-methyl-4 (or 5) is used. ) -T-Propenyl-1-cyclohexene oxide, 2,4- or 1,4-dimethyl-4ethenyl-1-cyclohexene oxide, 4-vinylcyclo [2,2,1] heptene-1
-Oxide (vinyl norbornene oxide), 2-methyl-4-isopropanyl-cyclohexene oxide and the like are used alone or in combination to perform ring-opening polymerization. At this time, it is also possible to coexist with another epoxy compound which does not belong to the above-mentioned partial epoxidized product and to carry out ring-opening copolymerization. As the other epoxidized compound which can be copolymerized, any one may be used as long as it has an epoxy group.
Oxides of unsaturated compounds such as ethylene oxide, propylene oxide, butylene oxide, styrene oxide; glycidyl ether compounds such as allyl glycidyl ether, 2-ethylhexyl glycidyl ether, methyl glycidyl ether, phenyl glycidyl ether; acrylic acid, methacrylic acid, etc. Examples of the unsaturated carboxylic acid glycidyl ester compound include alicyclic oxirane group-containing vinyl monomers such as 3,4-epoxycyclohexylmethyl (meth) acrylate.

The above ring-opening polymer can be obtained by subjecting a partial epoxidized compound alone or in combination with another epoxy compound as the case requires, and subjecting the epoxy group contained therein to ring-opening polymerization (ether bond). The composition ratio of the other epoxy compound in the ring-opening polymer can be arbitrarily selected according to the purpose, but specifically, the above structural formulas (a) to (d) per one molecule of the obtained ring-opening copolymer are used. It is desirable to select any one or more of them in the range of having 2 or more on average, preferably 3 or more, and more preferably 4 or more.

The number average molecular weight of the (co) polymer thus obtained is generally 400 to 100,000, especially 7
It is preferably in the range of 00 to 50,000, more preferably 700 to 30,000.

The ring-opening polymerization reaction is generally preferably carried out in the presence of a catalyst. Examples of usable catalysts include amines such as methylamine, ethylamine, propylamine and piperazine; pyridines and imidazoles. Organic bases; formic acid, acetic acid, propionic acid, and other organic acids; sulfuric acid, hydrochloric acid, and other inorganic acids; sodium methylate, and other alkali metal alcoholates; KOH, NaOH, and other alkalis; BF ₃ , ZnCl ₂ , AlCl ₃ , SnCl
Lewis acids such as ₄ or a complex thereof; organometallic compounds such as triethylaluminum, aluminum acetylacetonate, titanium acetylacetonate, and diethylzinc. These catalysts can be used generally in the range of 0.001 to 10% by weight, preferably 0.1 to 5% by weight based on the reactants. The ring-opening polymerization reaction temperature is generally within the range of about -70 to about 200 ° C, preferably about -30 ° C to about 100 ° C. The reaction can be carried out using a solvent, and it is preferable to use an ordinary organic solvent having no active hydrogen as the solvent.

The ring-opening polymer has a double bond based on the alicyclic compound (S), and the epoxy resin (II) can be obtained by epoxidizing all or part of the double bond. Epoxidation of the double bond can be carried out using an epoxidizing agent such as peracids and hydroperoxides. Whether or not a solvent is used in the epoxidation reaction and the reaction temperature can be appropriately adjusted depending on the apparatus used and the physical properties of the raw materials. Depending on the conditions of the epoxidation reaction, a side reaction may occur simultaneously with the epoxidation of the double bond in the raw material ring-opening polymer, and a modified substituent may be contained in the skeleton of the epoxy resin (II). As the modified substituent, for example, when peracetic acid is used as an epoxidizing agent, a substituent having the following structure can be given, which is considered to be due to the reaction between the generated epoxy group and by-product acetic acid. .

[Chemical 11]

The ratio in which these modified substituents are contained depends on the type of epoxidizing agent, the molar ratio of epoxidizing agent to unsaturated group, and the reaction conditions.

The epoxy resin (I
The epoxy equivalent of I) is generally in the range of 100 to 2,000, in particular 150 to 500, preferably 150 to 250.

Commercially available products can be used as the epoxy resin (II). For example, EHPE-3150, E
Examples thereof include HPE-3100 and EHPE-1150 [trade name, manufactured by Daicel Chemical Industries, Ltd.], which is an epoxy resin having the following structural formula and having a cyclohexane skeleton using 4-vinylcyclohexene-1-oxide.

[Chemical 12] (In the formula, X is an organic group, and n is 2 or more, preferably 3 or more, and more preferably 4 or more.)

Second production method : For example, it is obtained by epoxidizing at least two of the double bonds contained in the alicyclic compound (S) and then ring-opening polymerization so that the epoxy group remains.

As the epoxidized compound having an average of two or more epoxy groups per molecule, the following monocyclic or condensed ring compounds are typically shown.

[Chemical 13]

As a substrate, one or more of the above-mentioned epoxidized compounds are subjected to ring-opening polymerization reaction by using an initiator and a catalyst, if necessary, in the same manner as described in the above-mentioned first production method. The epoxy resin (II) is obtained by terminating the reaction at a predetermined reaction point at which the sine remains. Any means such as dilution with a solvent and cooling can be used to stop the reaction. Also in this manufacturing method, the other epoxy compound may be copolymerized as in the first manufacturing method.

The curing resin (II) thus obtained is composed of at least one of the epoxy group-containing functional groups represented by the formula (a) or (b) and the epoxy group represented by the formula (c) or (d). It is also possible to use an epoxy resin having at least one of the contained functional groups in the same molecule or in a different molecule.

The ring-opening polymer [curing resin (II)] thus obtained generally has a number average molecular weight of 400 to 10,
000, particularly preferably in the range of 700 to 50,000, and the epoxy equivalent is generally 100 to 2,
It is expedient to be in the range of 000, in particular 150 to 500, even 150 to 250.

Third manufacturing method : As a compound having at least one epoxy group-containing functional group and at least one polymerizable unsaturated bond in the same molecule (hereinafter, may be abbreviated as "polymerizable epoxy monomer") Examples include those represented by the following general formulas (1) to (12).

[Chemical 14]

[Chemical 15] (In the above general formula, R ₁₁ represents a hydrogen atom or a methyl group, R ₁₂ represents a divalent aliphatic saturated hydrocarbon group having 1 to 6 carbon atoms, and R ₁₃ represents a divalent aliphatic group having 1 to 10 carbon atoms. Represents a hydrocarbon group.)

In the above polymerizable epoxy monomer, R
_The divalent aliphatic hydrocarbon group having 1 to 6 carbon atoms represented by ₁₂ is a linear or branched alkylene group,
Examples thereof include methylene, ethylene, propylene, tetramethylene, ethylethylene, pentamethylene and hexamethylene groups. Examples of the divalent hydrocarbon group having 1 to 10 carbon atoms represented by R ₁₂ include methylene, ethylene, propylene, tetramethylene, ethylethylene, pentamethylene, hexamethylene, polymethylene, phenylene,

[Chemical 16] A group etc. can be mentioned.

Specific examples of the polymerizable epoxy monomers represented by the above general formulas (1) to (12) include 3,4-epoxycyclohexylmethyl acrylate and 3,4-epoxycyclohexylmethyl methacrylate. Examples of commercially available products thereof include METHB and AETHB (both are trade names) manufactured by Daicel Chemical Industries, Ltd., each of which has an epoxy group-containing functional group represented by the above formula (a) or (b). Is what you are doing. Further, 4-vinylcyclohexene oxide can also be used as the polymerizable epoxy monomer.

The epoxy resin (II) can be produced by polymerizing one kind or two or more kinds selected from the polymerizable epoxy monomers, but other polymerizable unsaturated monomers can also be copolymerized at that time. .

As the other polymerizable unsaturated monomer,
A wide range of selection can be made according to the desired performance of the (co) polymer obtained, and typical examples thereof are as follows.

(A) Ester of acrylic acid or methacrylic acid: for example, methyl acrylate, ethyl acrylate,
Propyl acrylate, isopropyl acrylate, butyl acrylate, hexyl acrylate, octyl acrylate, lauryl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, hexyl methacrylate, methacrylic acid C1 to C18 alkyl esters of acrylic acid or methacrylic acid such as octyl and lauryl methacrylate; methoxybutyl acrylate, methoxybutyl methacrylate, methoxyethyl acrylate, methoxyethyl methacrylate, ethoxybutyl acrylate, ethoxy methacrylate. C2-C18 alkoxyalkyl ester of acrylic acid or methacrylic acid such as butyl; acrylic acid or methacrylic acid such as allyl acrylate and allyl methacrylate C2-C8 alkenyl ester; C2-C8 hydroxyalkyl ester of acrylic acid or methacrylic acid such as hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, and hydroxypropyl methacrylate; allyloxyethyl acrylate, allyloxymethacrylate C3-18 alkenyloxyalkyl esters of acrylic acid or methacrylic acid such as.

(B) Vinyl aromatic compound: For example, styrene, α-methylstyrene, vinyltoluene, p-chlorostyrene.

(C) Polyolefin compound: For example,
Butadiene, isoprene, chloroprene.

(D) Others: acrylonitrile, methacrylonitrile, methyl isopropenyl ketone, vinyl acetate baoba monomer (shell chemical product), vinyl propionate, vinyl pivalate, vinyl compound having a polycaprolactone chain (for example, FM-3X). Monomer: trade name manufactured by Daicel Chemical Industries).

The composition ratio of the polymerizable epoxy monomer and the other polymerizable unsaturated monomer can be arbitrarily selected according to the purpose, and one molecule of the epoxy resin (II) obtained by the copolymerization reaction of them can be selected. The epoxy group-containing functional group can be selected in such a range that it contains at least 2, preferably 3 or more on average, and more preferably 4 or more on average, but it is used as a functional group that imparts sufficient curability. In order to achieve, the content of the polymerizable epoxy monomer in the solid content of the epoxy resin (II) is 5 to 100% by weight,
It is more preferable that the amount is in the range of 20 to 100% by weight.

The epoxy resin (II) obtained by the third production method described above can be produced by using the same method and conditions as the polymerization reaction based on a polymerizable unsaturated bond of a usual acrylic resin or vinyl resin. it can. As an example of such a polymerization reaction, each monomer component is dissolved or dispersed in an organic solvent, and the reaction is carried out in the presence of a radical polymerization initiator at 60-18.
A method of heating with stirring at a temperature of about 0 ° C. can be shown. The reaction time can be usually about 1 to 10 hours. Further, as the organic solvent, an alcohol solvent, an ether solvent, an ester solvent, a hydrocarbon solvent or the like can be used. When a hydrocarbon solvent is used, it is preferable to use another solvent in combination from the viewpoint of solubility. Further, any of those usually used as a radical initiator can be used, and specific examples thereof include peroxides such as benzoyl peroxide and t-butylperoxy-2-ethylhexanoate; azoisobutylnitrile. , Azo compounds such as azobismethylvaleronitrile, and the like.

Epoxy resin (II) of the third production example
Generally has a number average molecular weight of about 3,000 to about 100,0.
Those in the range of 00 are preferable, and particularly 4,000 to
Those in the range of 10,000 are more preferable.

Among the above-mentioned curable resins (II), 1 is suitable for use in applications requiring high performance such as cationic electrodeposition coatings used for automobile bodies.
It has an average of 3 or more epoxy group-containing functional groups per molecule, more preferably 4 or more on average, most preferably 5 or more on average, and the epoxy equivalent is preferably 100 to 2 , 000, more preferably 1
50 to 500, in particular 150 to 250, and a number average molecular weight of preferably 400 to 100,000.
0, more preferably 700 to 50,000, and particularly preferably 700 to 30,000.

The amount of the curing resin (II) used depends on the type of the base resin (I) used, and also the minimum amount necessary for heat curing of the resulting coating film or the stability of the cationic electrodeposition coating composition. It can be appropriately changed within the range of the maximum amount, but generally, the weight ratio of the solid content of the curing resin (II) to the base resin (I) is 0.2 to 1.0, particularly 0.25.
It is preferable to select 0.85, more preferably 0.25 to 0.65.

A part of the curing resin (II) is the base resin (I)
It does not matter even if the ones added in advance are included.

Thus, the base resin (I) and the curing resin (I
The composition comprising I) can be used as the cationic electrodeposition coating composition (A-1).

In particular, the electrodeposition coating film of the coating material (A-1)
In order to cure sufficiently at a low temperature of 60 ° C. or lower, it is selected from lead compounds, zirconium compounds, cobalt compounds, aluminum compounds, manganese compounds, copper compounds, zinc compounds, iron compounds, chromium compounds, nickel compounds, etc. 1 It is effective to add one kind or two or more kinds of metal compounds as a catalyst. Specific examples of these metal compounds include chelate compounds such as zirconium acetylacetonate, cobalt acetylacetonate, aluminum acetylacetonate, and manganese acetylacetonate; compounds having a β-hydroxyamino structure and lead (II) oxide. Chelation reaction products; lead 2-ethylhexanoate, lead naphthylate, lead octylate, lead benzoate, lead acetate, lead lactate, lead formate, lead glycolate, carboxylates such as octix zirconium, and the like.

The metal compound is used in an amount of generally 10% by weight or less, preferably 5% by weight or less, based on the total solid weight of the base resin (I) and the curing resin (II). be able to.

Next, as the coating material (A-2), a cationic electrodeposition coating material containing a resin (I) having a hydroxyl group and a cationic group and a blocked polyisocyanate compound (III) as main components can be mentioned.

As the resin (I), the paint (A-
A resin selected from the base resin (I) described in 1) is preferable.

Block polyisocyanate compound (III)
Is an addition reaction product of a theoretical amount of a polyisocyanate compound and an isocyanate blocking agent, and is used as a crosslinking agent of the resin (I). Examples of the polyisocyanate compound include aromatic compounds such as tolylene diisocyanate, xylylene diisocyanate, phenylene diisocyanate, bis (isocyanatomethyl) cyclohexane, tetramethylene diisocyanate, hexamethylene diisocyanate, methylene diisocyanate, and isophorone diisocyanate, alicyclic compounds, and fatty acids. Group isocyanate-containing prepolymers obtained by reacting a low molecular weight active hydrogen-containing compound such as ethylene glycol, propylene glycol, trimethylolpropane, hexanetriol, or castor oil with an excess amount of a polyisocyanate compound of the group and these isocyanate compounds. To be Also, the isocyanate blocking agent is one that blocks by adding to the isocyanate group of the polyisocyanate compound, and the blocked polyisocyanate compound generated by the addition is stable at room temperature and dissociates the blocking agent when heated above the dissociation temperature. It is important that the free isocyanate group can be regenerated.

Particularly in the present invention, the loss on heating of the cationic electrodeposition coating film must be 10% by weight or less, so that it is preferable to use a low molecular weight compound having a molecular weight of 130 or less as the blocking agent. Specifically, phenol-based blocking agents such as phenol, cresol, xylenol, chlorophenol and ethylphenol; lactam-based blocking agents such as ε-caprolactam, δ-valerolactam, γ-butyrolactam and β-propiolactam;
Active methylene-based blocking agents such as ethyl acetoacetate and acetylacetone; methanol, ethanol, propanol, butanol, amyl alcohol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, propylene glycol monomethyl ether, benzyl. Alcohol, methyl glycolate, butyl glycolate, diacetone alcohol, alcohol-based blocking agents such as methyl lactate and ethyl lactate; formamidoxime, acetaldoxime, acetoxime, methylethylketoxime,
Oxime-based blocking agents such as diacetyl monooxime and cyclohexane oxime; mercaptan-based blocking agents such as butyl mercaptan, hexyl mercaptan, t-butyl mercaptan, thiophenol, methylthiophenol, ethylthiophenol; acid amide-based blocks such as acetic acid amide and benzamide Agents; imide-based blocking agents such as succinimide and maleic imide; amine-based blocking agents such as xylidine, aniline, butylamine, dibutylamine; imidazole-based blocking agents such as imidazole and 2-ethylimidazole; ethyleneimine, propyleneimine, etc. Imine blocking agent of
And so on. Of these, an oxime-based blocking agent such as methyl ethyl ketoxime is particularly preferable in terms of the balance of the stability of the coating material and the curability of the coating film.

The ratio of the base resin (I) to the block polyisocyanate compound (III) in the coating material (A-2) is not particularly limited, but it is based on the total solid content of the two components. ) Is 40-95% by weight, especially 6
0 to 90% by weight, blocked polyisocyanate compound (I
II) is preferably 60 to 5% by weight, particularly preferably 40 to 10% by weight.

The above paint (A-1) and paint (A-2)
In the cationic electrodeposition coating composition (A) such as the above, gelled fine particles and / or pigments can be blended as a particulate component for controlling the melt viscosity of the coating film. It is preferable to use.

The gelled fine particles are not particularly limited as long as they are fine particle polymers gelled by a crosslinking reaction in the particles, and conventionally known ones can be used, for example, an acrylic resin containing an alkoxysilane group and a cationic group. A copolymer in which the copolymer is dispersed in water and crosslinked within the particles (Japanese Patent Application No. 62-541).
No. 41); internally crosslinked gelled fine particles having an alkoxysilane group, a hydroxyl group and a cationic group.
-47173); and internal cross-linked gelled fine particles having an alkoxysilane group, a urethane bond, a hydroxyl group and a cationic group (see JP-A-3-62860).

In the present invention, as the gelled fine particles, the cationic electrodepositable gelled fine particles obtained by water-dispersing an epoxy resin amine adduct containing a hydrolyzable alkoxysilane group and cross-linking within the particles are anticorrosive. It can be preferably used from the viewpoint of sex. The gelled fine particles will be described below.

The above-mentioned "epoxy resin amine adduct containing a hydrolyzable alkoxysilane group" is a product obtained by introducing a hydrolyzable alkoxysilane group into an epoxy resin amine adduct, and is a cationic group, especially an acid. The hydrated amino group is stably dispersed in water as a water-dispersing group, and the silanol group produced by the hydrolysis of the alkoxysilane group is condensed with the silanol groups and, if there is a hydroxyl group, the hydroxyl group. The term refers to an adduct that can be gelled by intra-particle crosslinking.

The epoxy resin amine adduct which is a constituent of the gelled fine particles includes those such as (i) mentioned in the base resin (I) of the coating material (A-1).

The method for introducing the hydrolyzable alkoxysilane group into the epoxy resin amine adduct is not particularly limited, and it may be selected from the methods known per se depending on the kind of the hydrolyzable alkoxysilane group to be introduced. However, it is preferable to employ a method that does not generate a by-product such as water-soluble salts that adversely affects electrodeposition coating. For example, the following method can be exemplified.

(1) Method of adding an alkoxysilane group-containing amine compound to an epoxy group in a base resin: Examples of amine compounds that can be used here include those of the following formulae.

[0103]

[Chemical 17]

(2) Method of adding mercaptan containing alkoxysilane group to epoxy group in base resin: Examples of the mercaptan which can be used here include the following.

[0105]

[Chemical 18]

(3) Method of adding an alkoxysilane group-containing epoxy compound to an amino group in a base resin: Examples of epoxy compounds that can be used here include the following compounds.

[0107]

[Chemical 19]

(4) Method for adding an alkoxysilane group-containing isocyanate compound to the hydroxyl group and amino group in the base resin: Examples of the isocyanate compound that can be used here include those of the following formula.

[0109]

[Chemical 20]

In each of the formulas described above, R may be exemplified as follows: (i) --CH ₃ , --C ₂ H ₅ , --C ₃ H ₇ , --C ₄ H.
_9, an alcohol residue such as _{-C 6 H 13, -C 8 H} 17: (ii) -C 2 H 4 OCH 3, -C 2 H 4 OC 2 H 5, -
_{C 2 H 4 OC 3 H 7} , -C 2 H 4 OC 4 H 9, -C 3 H
₆ OCH ₃ , -C ₃ H ₆ OC ₂ H ₅ , -C ₄ H ₈ OCH
_{3, -C 2 H 4 OC 2} H 4 OCH 3, -C 2 H 4 OC 2
H ₄ OC ₂ H _5, ether alcohol residue such as _{-C 2 H 4 OC 2 H 4} OC 4 H 9:

(Iii)

[Chemical 21]

(Iv) Cycloalkyl or aralkyl alcohol residue such as phenyl group and benzyl group:

(V)

[Chemical formula 22]

Oxime alcohol residues such as:

(Vi) Other

[Chemical formula 23]

Etc.

R in the above formula has a smaller number of carbon atoms and is more easily hydrolyzed, but is inferior in stability, and therefore, a carbon number of about 2 to 7 is advantageous in terms of balance. Further, ones having 2 or less carbon atoms and those having 7 or more carbon atoms may be combined and balanced.

Water dispersion of the above epoxy resin amine adduct containing a hydrolyzable alkoxysilane group can be carried out by a method known per se. For example, an epoxy resin amine adduct containing the above hydrolyzable alkoxysilane groups can be added to the amine group present at about 0.
By neutralizing with 1 to 1 equivalent of an acid, for example, a water-soluble carboxylic acid such as formic acid, acetic acid, lactic acid, hydroxyacetic acid, etc., and then dispersing in water so that the solid content concentration is about 40% by weight or less. Can be done.

The dispersed particles of the epoxy resin amine adduct containing hydrolyzable alkoxysilane groups thus obtained can then be intraparticle crosslinked. Intraparticle crosslinking may proceed to some extent by simply storing the dispersion for an extended period of time, but it is advantageous to heat the aqueous dispersion to a temperature of about 50 ° C. or higher to effect intraparticle crosslinking. It is desirable to promote. Alternatively, when water-dispersing the epoxy resin amine adduct containing the hydrolyzable alkoxysilane group, tin octylate, zinc octylate, zirconium octylate, dibutyltin dilaurate, etc. in the resin solution or in the aqueous medium are used. By adding a silanol group condensation catalyst and performing water dispersion in the presence of the catalyst, intraparticle crosslinking can be performed simultaneously with water dispersion.

The gelled fine particle aqueous dispersion thus produced is usually about 10 to 40% by weight, preferably 15 to 40% by weight.
It may have a resin solids content of 30% by weight. The particle size of the dispersed particles is generally 0.5 μm or less, preferably 0.01 to 0.3 μm, and more preferably 0.05 to
It can be in the range of 0.2 μm. The particle size can be adjusted by adjusting the amount of the cationic groups in the epoxy resin amine adduct containing the hydrolyzable alkoxysilane group, thereby easily obtaining the particle size within the desired range. You can

The amount of the gelled fine particles to be incorporated in the cationic electrodeposition coating composition (A) is not particularly limited as long as the melt viscosity of the coating film is adjusted within the above range, but any gelled fine particle is used. Even if the total resin solid content is 3
-50% by weight, preferably 7-35% by weight is suitable.

When blending the above-mentioned gelled fine particles, if necessary, other particulate components such as carbon black, titanium white, lead white, lead oxide, red pigment such as red iron oxide, extender pigment such as clay and talc; Strontium chromate, lead chromate, basic lead chromate, red lead, lead silicate,
Anticorrosion pigments such as basic lead silicate, lead phosphate, basic lead phosphate, lead tripolyphosphate, lead silicochromate, yellow lead, cyanamide lead, calcium leadate, lead zinc sulfate, lead sulfate, and salt yellow lead sulfate. You may use together.

When only the pigment is mixed in the cationic electrodeposition coating composition (A) as the particulate component, a pigment having an oil absorption of 100 or more, for example, a silicon dioxide pigment or a carbon pigment is contained in an amount of 5% by weight based on all pigments. It is appropriate to mix the above.

The cationic electrodeposition coating composition (A) may further contain a conventional additive for coating composition, if necessary. Examples of the additive include a small amount of a nonionic surfactant as a dispersant or an anti-repellent agent for the coated surface; a curing accelerator and the like.

The film thickness of the coating film obtained by electrodepositing the cationic electrodeposition coating composition thus prepared on the substrate is not strictly limited, but in general, it is 3 based on the dry film thickness. It is suitable to be in the range of ˜200 μm, preferably 5 to 100 μm, more preferably 10 to 40 μm. The coating can be carried out using usual cationic electrodeposition coating conditions. For example, a cationic electrodeposition bath having a bath concentration (solid content concentration) of 5 to 40 wt%, preferably 10 to 25 wt% and a bath pH of 5 to 8, preferably 5.5 to 7, is prepared. Then, using this electrodeposition bath, for example, 5 cm x 15 cm
A carbon plate having a size of × 1 cm is used as an anode and, for example, 5
When a zinc phosphate-treated plate having a size of cm × 15 cm × 0.7 mm is used as a cathode, electrodeposition can be performed under the following conditions. Bath temperature: 20 to 35 ° C., preferably 25 to 30 ° C., direct current Current density: 0.005 to ^{2 A} / cm ² , preferably 0.
01 to 1 A / cm ² voltage: 10 to 500 V, preferably 100 to 300
V energization time: 0.5 to 5 minutes, preferably 2 to 3 minutes

In the method of the present invention, after the above coating composition (A) is subjected to cationic electrodeposition coating, the object to be coated is pulled out from the electrodeposition bath and washed with water, and then water droplets on the surface of the electrodeposition coating film are removed, more preferably electrodeposition. Most or all of the water contained in the coating film is removed by a drying means such as hot air (for example, about 80 to 110 ° C. for about 5 to 10 minutes is suitable), and then the uncured (including semi-cured)
Apply anti-chipping primer to the surface of the coating.

As the primer that can be used in the present invention (hereinafter sometimes abbreviated as "paint (B)"), a primer known per se which is excellent in chipping resistance and the like can be used. Specifically, for example, Japanese Patent Laid-Open No. 61-120673
First, a barrier coat mainly composed of a modified polyolefin resin having a static glass transition temperature of a formed coating film of −30 to −60 ° C., preferably −40 to −50 ° C., as described in JP-A No. 2003-242242, etc. . The coating material is of an organic solvent type, and as such a modified polyolefin resin, for example, a propylene-ethylene copolymer (molar ratio: 40 to 80:60) is used.
˜20% is suitable), and 1 to 50 parts by weight, preferably 10 to 2 parts of chlorinated polyolefin (chlorination rate of about 1 to 60%).
0 parts by weight (all per 100 parts by weight of the copolymer), or 0.1 to 50 parts by weight of maleic acid or maleic anhydride per 100 parts by weight of the propylene-ethylene copolymer. Preferably 0.3-
20 parts by weight of a resin which has been graft-polymerized may be used. If necessary, a viscosity-imparting agent such as rosin or coumarone may be added to these resins. The static glass transition temperature of the formed coating film is a value measured by a differential scanning calorimeter (DSC-10 type manufactured by I Seikosha Co., Ltd.), and the sample used for this measurement is based on the barrier coating formed film. 2
Paint it on the tin plate so that it becomes 5 μm,
After baking for 1 minute, it was isolated by the mercury amalgam method.

Further, examples of the chipping-resistant primer that can be used include an aqueous primer containing a polyurethane emulsion obtained by chain elongation of a carboxyl group-containing polyurethane polymer in the presence of an aqueous medium. It can be preferably used from the viewpoint of sex.

The aqueous primer is not particularly limited as long as it is a urethane emulsion as described above.
Preferably in the presence or absence of a hydrophilic organic solvent containing no active hydrogen group in the molecule, (i) an aliphatic and / or alicyclic diisocyanate, (ii) a number average molecular weight of 500 to
5,000 polyether diols or polyester diols or mixtures thereof, (iii) low molecular weight polyhydroxyl compounds and (iv) dimethylolalkanoic acid,
When the CO / OH equivalent ratio is within the range of 1.1 to 1.9,
When a urethane prepolymer is synthesized by polymerizing by a one-shot method or a multi-step method, and then the prepolymer is mixed with water after or while being neutralized with a tertiary amine, a water elongation reaction is carried out. At the same time, an aqueous dispersion of a self-emulsifying urethane resin having an average particle size of about 0.001 to 1.0 μm, which is prepared by simultaneously emulsifying and dispersing in water and then distilling off the organic solvent, is suitable.

As the component (i) used for producing the urethane prepolymer, aliphatic diisocyanates having 2 to 12 carbon atoms, such as hexamethylene diisocyanate and lysine diisocyanate; alicyclic diisocyanates having 4 to 18 carbon atoms, such as 1 , 4-cyclohexane diisocyanate, 1-isocyanato-3-isocyanatomethyl-3,5,5-trimethylcyclohexane (isophorone diisocyanate), 4,4'-dicyclohexylmethane diisocyanate; modified products of these diisocyanates (carbodiimide, uretdione, uretoimine And modified mixtures thereof, and examples of the component (ii) include alkylene oxides (ethylene oxide, propylene oxide, butylene oxide, etc.) and / or Or those obtained by polymerizing or copolymerizing (block or random) a heterocyclic ether (tetrahydrofuran etc.), for example polyethylene glycol, polypropylene glycol, polyethylene-propylene (block or random) glycol, polytetramethylene ether glycol; dicarboxylic acid Those obtained by polycondensing (adipic acid, succinic acid, maleic acid, fumaric acid, phthalic acid, etc.) and glycol (ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, etc.), for example, Polyethylene adipate, polybutylene adipate, polyhexamethylene adipate, polyneopentyl adipate, poly-3-
Methylpentyl adipate, polyethylene / butylene adipate, polyneopentyl / hexyl adipate; polylactone diols such as polycaprolactone diol, poly-3-methylvalerolactone diol; polycarbonate diol; and mixtures of two or more thereof.

Used in the production of the prepolymer (ii)
The component i) has a number average molecular weight of less than 500, for example, the glycols and their alkylene oxide low-molar adducts (molecular weight less than 500) mentioned as the raw materials of the above polyester diols; trihydric alcohols such as glycerin and trimethylolethane, Trimethylolpropane and its alkylene oxide low molar adducts (molecular weight 50
Less than 0); and mixtures of two or more thereof. The amount of the low molecular weight polyhydroxyl compound is usually 0.1 to 20% by weight, preferably 0.5 to 10% by weight, based on the above polyether diol or polyester diol. Examples of the component (iv) include dimethylol acetic acid, dimethylol propionic acid, dimethylol acetic acid, dimethylol propionic acid, and dimethylol butyric acid. The amount of dimethylolalkanoic acid is 0.5 to 5% by weight, preferably 1 to 3% by weight in the urethane prepolymer obtained by reacting (i) to (iv) as a carboxyl group (—COOH). is there. If the amount of carboxyl groups is less than 0.5% by weight, it is difficult to obtain a stable emulsion,
When it exceeds 5% by weight, the hydrophilicity becomes high, so that the emulsion has a remarkably high viscosity and the water resistance of the coating film tends to be lowered. Further, the carboxyl group can improve the adhesion to the cationic electrodeposition coating film and the intermediate coating film.

Examples of the tertiary amine used for neutralizing the acid group include trialkylamines such as trimethylamine,
Triethylamine, triisopropylamine, tri-n
-Propylamine, tri-n-butylamine; N-alkylmorpholines, such as N-methylmorpholine, N-ethylmorpholine; N-dialkylalkanolamines,
Examples thereof include N-dimethylethanolamine, N-diethylethanolamine; and a mixture of two or more thereof. Of these, preferred is trialkylamine, and particularly preferred is triethylamine. The neutralization amount of the tertiary amine is usually 0.5 to 1 equivalent, preferably 0.7 to 1 equivalent based on 1 equivalent of the carboxyl group of dimethylolalkanoic acid.

If necessary, the coating composition (B) as described above may contain an extender pigment, a coloring pigment, an ultraviolet absorber, an antioxidant and the like.

The coating method of the coating material (B) is not particularly limited and includes, for example, spray coating, brush coating, dip coating, etc., and the coating film thickness is about 1 to 20 μm in dry film thickness, especially 5 to 1 μm.
5 μm is preferable.

In the method of the present invention, the primer coating film is formed on the surface of the uncured electrodeposition coating film, and if necessary, the coating surface is preheated at about 60 to 100 ° C. for 3 to 10 minutes (especially aqueous solution). This is preferable in the case of a primer), and then an intermediate coating composition or a direct top coating composition is applied to the surface of the uncured coating film, followed by heating to simultaneously cure the three-layer coating film. When an excellent finished appearance is required, it is preferable to apply an intermediate coating material on the primer coating surface to simultaneously cure the three-layer coating film, and then top coat.

According to the present invention, when the intermediate coating material is applied to the primer coating surface, the intermediate coating material used has excellent adhesiveness, smoothness, sharpness, overbaking resistance, weather resistance and the like. A known intermediate coating composition can be used. Specifically, an organic solution type thermosetting intermediate coating composition containing a short oil having an oil length of 30% or less, an ultra short oil alkyd resin or an oil-free polyester resin and an amino resin as a vehicle main component is first mentioned. These alkyd resins and polyester resins have a hydroxyl value of 60 to 140, an acid value of 5 to 40,
Moreover, unsaturated oil (or unsaturated fatty acid) as modified oil
Is preferred, and the amino resin is an alkyl (C 1-5) etherified melamine resin, urea resin,
Benzoguanamine resin is suitable. These compounding ratios are based on the solid content weight, and are alkyd resin and / or oil-free polyester resin 65-85%, especially 70-80%, amino resin 35-15%, especially 30-2.
It is preferably 0%. Furthermore, the amino resin can be replaced with a polyisocyanate compound or a blocked polyisocyanate compound.

As the intermediate coating composition which can be used, those having the form of an aqueous solution using the vehicle component as described above, an aqueous dispersion type, a non-aqueous dispersion type, a high solid type and the like can also be mentioned.

Further, an alicyclic epoxy compound may be contained in the intermediate coating composition containing the above polyester resin and amino resin in order to improve the curability of the coating film. The alicyclic epoxy compound has one molecule of at least one epoxy group selected from an epoxy group on an alicyclic hydrocarbon ring and an epoxy group directly bonded to a carbon atom forming the alicyclic hydrocarbon ring. It has at least two or more. The alicyclic hydrocarbon ring may be a 3-membered small-membered ring to a 7-membered or more-membered ring, and the ring may be a monocyclic ring or a polycyclic ring. It may form a hydrocarbon ring.

The alicyclic epoxy compound can be used without particular limitation as long as it is industrially available, and specific examples thereof include the following.

[0140]

[Chemical formula 24]

Furthermore, compounds having the following general formula and unit formula (1), (2) or (3) are also included.

[0142]

[Chemical 25] (In the formula, R ₁ is an organic residue having active hydrogen, and p is 2 to 100.)

[0143]

[Chemical formula 26] (In the formula, p has the same meaning as described above.)

[0144]

[Chemical 27] (In the formula, Y is an alicyclic epoxy residue, and X is

[Chemical 28] R ₂ is a C _1-18 alkyl group or a cycloalkyl group, R ₃ is a C _1-6 alkylene group, and n is 0 to 1
00 and m is 5 to 100. )

Y in the unit formula (3) is

[Chemical 29] Is an organic group having an alicyclic epoxy group.

The compounds having the above unit formulas (1) to (3) are produced according to the first production method or the third production method in the production of the epoxy resin (II) of the coating material (A). As specific examples, commercially available products include compounds having the general formula (I), such as EHPE-3150 and EHPE-3100.
EHPE-1150 (above, product name by Daicel Chemical Industries, Ltd.) and the like can be mentioned.

The alicyclic epoxy compound has a number average molecular weight of 100,000 or less, preferably about 50,000 or less, more preferably 30,000 or less, and the number of alicyclic epoxy groups is about 2 to 400 on average. Those are preferable.

When the alicyclic epoxy compound is blended in the intermediate coating composition, the amount is about 1 to 100 parts by weight based on the total weight (solid content) of the polyester resin and the amino resin.
It is desirable to add 20 parts by weight, preferably about 2 to 10 parts by weight.

If necessary, an extender pigment, a coloring pigment, and other additives for paints can be added to the above intermediate coating material.

The method of coating the intermediate coating material is not particularly limited, and a method known per se can be adopted, and examples thereof include spray coating, brush coating, dip coating, electrostatic coating, and the like, and the coating film thickness is Generally 10-5 based on dry coating
A range of 0 μm, particularly 20 to 30 μm is preferable.

In the case of applying a topcoat paint to the surface of the primer coating film or the intermediate coating film according to the present invention, the topcoat paint used is a paint which imparts beauty to the article to be coated,
It can be appropriately selected from conventional ones and used without particular limitation. Specifically, acrylic resin, polyester resin, silicon resin, fluororesin and modified resins thereof are used as the base resin component, and (block) polyisocyanate compound, melamine resin, metal chelate and alkoxysilane compound are used as a cross-linking agent (or catalyst). A), an aqueous solvent, an organic solvent type or a non-aqueous dispersion type, a powder type, a high solid type, etc.

The top coat paint is a metallic paint or a solid color finish paint in which a metallic pigment and / or a coloring pigment is added to the above-mentioned paint using the vehicle main component and a clear paint (color clear paint) containing no or almost no such pigment. Including)). And as a method of forming an overcoat coating film using these paints, the following are mentioned, for example.

A metallic pigment, a metallic paint containing a coloring pigment if necessary, or a solid color paint containing a coloring pigment is applied and cured by heating. A metallic paint or a solid color paint is applied and cured by heating, and then a clear paint is further applied and cured by heating again. A metallic paint or a solid color paint is applied, and then a clear paint is applied, followed by heating to simultaneously cure the both paint films.

It is preferable that these top coating materials are applied by spray coating, electrostatic coating or the like. The coating film thickness is 25 to 45 μm in the above case, 10 to 30 μm in the metallic paint and the solid color paint, and 25 to 50 μm in the clear paint based on the dry coating film.
Are preferred.

In the method of the present invention, the cation electrodeposition coating (A) is subjected to cation electrodeposition coating, a primer is applied to the uncured coating surface without heat curing, and an intermediate coating composition or a direct top coating composition is further applied. After painting, heat to 3
The layer coating is cured simultaneously. The heating temperature for curing these coating films is not particularly limited, but specifically,
The range of 70 to 250 ° C, particularly 120 to 160 ° C is preferable. Suitably heating at this temperature for 15-40 minutes.
When the above-mentioned overcoating is carried out after the intermediate coating is applied on the primer coating film, the heating conditions of the above overcoating can be arbitrarily selected depending on the vehicle component and the material of the article to be coated, but generally about 60 ~ About 140 ° C, especially 80-1
10 to 40 minutes at 40 ° C is preferable.

[0156]

EFFECTS OF THE INVENTION According to the method of the present invention, the electrodeposition coating film, the chipping-resistant primer coating film on the coating film, and the coating film of the intermediate coating or the top coating composition are cured by the 3 coat 1 bake system, and therefore the cation is Since no heating and drying furnace for curing only the electrodeposition coating film is required, all the equipment cost, site and furnace lining expenses (fuel cost, maintenance cost, etc.) can be omitted, and the conventional 3 coat 3 bake method or Significant cost advantages can be expected compared to the 3 coat 2 bake system. In addition, the edge coverage of the electrodeposition coating is good,
Further, the multi-layer coating film formed by the present invention, even if the coating process is shortened, bleeding due to the electrodeposition film, the occurrence of curing inhibition is suppressed, the chipping resistance of the primer coating film is sufficiently exerted, and It has excellent finishing properties such as smoothness, gloss, and sharpness, adhesion, moisture resistance, and curability.

[0157]

EXAMPLES Next, the present invention will be described more specifically by way of examples. In the examples, "part" is "part by weight" and "%" is "% by weight".

I Production Example I-1 Production of Base Resin (I) Base Resin (I-) Bisphenol A type epoxy resin having an epoxy equivalent of 950 [trade name "Epicoat 1004, Shell Chemical Co., Ltd.]
1,900 parts was dissolved in 993 parts of butyl cellosolve, 210 parts of diethanolamine was reacted to give a solid content of 68%,
A base resin (I-) having a primary hydroxyl equivalent of 528 and an amine value of 53 was obtained.

Base Resin (I-) 39 parts of monoethanolamine was kept at 60 ° C. in a reaction vessel, and N, N-dimethylaminopropylacrylamide 1
00 parts was added dropwise and the mixture was reacted at 60 ° C. for 5 hours to obtain a monoethanolamine adduct of N, N-dimethylaminopropylacrylamide. Separately, 950 parts of bisphenol A diglycidyl ether having an epoxy equivalent of 190, 340 parts of propylene glycol diglycidyl ether having an epoxy equivalent of 340, 456 parts of bisphenol A and 21 parts of diethanolamine were charged and the temperature was raised to 120 ° C. to obtain an epoxy value of 1.02 mmol / After reacting to g, dilute with 479 parts of ethylene glycol monobutyl ether,
After cooling, while maintaining the temperature at 100 ° C., 158 parts of diethanolamine and the monoethanolamine adduct 4 of the above N, N-dimethylaminopropylacrylamide.
Three parts were added and the reaction was continued until the increase in viscosity stopped, to obtain a base resin (I-) having a resin solid content of 80%, a primary hydroxyl group equivalent of 518, and an amine value of 54.

Base Resin (I-) 950 parts of bisphenol A diglycidyl ether having an epoxy equivalent of 190 and epoxy resin X having an epoxy equivalent of 330
B-4122 (trade name, manufactured by Ciba Geigy), 330 parts, 456 parts of bisphenol A and 21 parts of diethanolamine were charged, the temperature was raised to 120 ° C., and the epoxy value was 1.0.
After reacting to 2 mmol / g, the mixture was diluted with 489 parts of ethylene glycol monobutyl ether and cooled, and then 126 parts of diethanolamine, 53.5 parts of the monoethanolamine adduct of N, N-dimethylaminopropylacrylamide and N- Methylaminoethanol 1
8.5 parts of a base resin (I-) having a resin solid content of 80%, a primary hydroxyl group equivalent of 592 and an amine value of 55 was added and reacted.
Got

I-2 Production of Curing Resin (II) Curing Resin (II-) EHPE3150 [epoxy equivalent 175 to 195, manufactured by Daicel Chemical Industries, Ltd.] 32.6 parts and propylene glycol monomethyl ether 8.2 parts 100 parts Melt by heating at ℃
Curing resin with solid content of 80% and epoxy equivalent of 190 (II-
) 40.8 parts were obtained. The number average molecular weight of the resin is about 1,
It was 500.

Curing resin (II-) 200 parts of a 10% ethyl acetate solution of BF ₃ -etherate in 136 parts of vinyl norbornene oxide, 124 parts of 4-vinylcyclohexene-1-oxide and 18 parts of trimethylolpropane were added at 50 ° C. Ring-opening polymerization was carried out by dropwise addition over time. After adding ethyl acetate and washing with water and concentrating the ethyl acetate layer, 130 parts of ethyl acetate was newly added and dissolved, and 160 parts of peracetic acid was added dropwise as an ethyl acetate solution at 50 ° C over 4 hours, and further 50 ° C. The mixture was aged for 2 hours to carry out an epoxidation reaction. After removing acetic acid, ethyl acetate and peracetic acid, it was dissolved in 500 parts of ethyl acetate at 40 ° C, followed by 2
After washing 4 times with 50 parts of distilled water, the ethyl acetate was removed,
It is dissolved in 78 parts of propylene glycol monomethyl ether at ℃ to obtain a curing resin (II-) having a solid content of 80% and an epoxy equivalent of 202. The number average molecular weight of the resin is about 1,
It was 300.

Curing Resin (II-) 304 parts of limonene partially epoxidized product (2-methyl-4-isopropenyl-1-cyclohexene oxide) and 18 parts of trimethylolpropane, and 10% ethyl acetate solution of BF ₃ -etherate. 200 parts was added dropwise at 50 ° C. over 4 hours. The following operation is carried out in the same manner as in the curing resin (II-), and dissolved in 80 parts of ethylene glycol monobutyl ether at 80 ° C. to obtain a solid content of 80% and an epoxy equivalent of 2
The curing resin (II-) of No. 05 is obtained. The number average molecular weight of the resin was about 1,000.

Curing Resin (II-) Using 304 parts of 2,4- or 1,4-dimethyl-4ethenyl-1 cyclohexene oxide, the curing resin (II-
), Solid content 80%, epoxy equivalent 19
A curing resin (II-) of 9 is obtained. The number average molecular weight of the resin was about 950.

Curing Resin (II-) Celoxide 3000 [

[Chemical 30] Trade name, manufactured by Daicel Chemical Industries, Ltd.] 460 parts, aluminum acetylacetonate 0.3 parts and tetraethoxysilane 5 parts, and 0.1 part of distilled water was added, and the mixture was kept at 80 ° C. for 1 hour and then at 120 ° C. for 3 hours. After the reaction, 116 parts of ethylene glycol monobutyl ether is added to obtain a curing resin (II-) having a solid content of 80% and an epoxy equivalent of 280. The number average molecular weight of the resin was about 1,100.

Curing Resin (II-) 132 parts of a dimer of cyclopentadiene was mixed with 70 parts of ethyl acetate.
And 160 parts of peracetic acid as an ethyl acetate solution.
The mixture was added dropwise at 5 ° C over 7 hours, and then aged at 40 ° C for 6 hours. After removing acetic acid, ethyl acetate and peracetic acid, ethyl acetate 5
It was dissolved in 00 parts at 40 ° C., followed by washing with 250 parts of distilled water 5 times, ethyl acetate was removed, and it was dissolved in 43 parts of methyl isobutyl ketone at 80 ° C. to obtain a compound having a solid content of 80% and an epoxy equivalent of 90. (D) was obtained.

94 parts of 4-vinylcyclohexene was dissolved in 75 parts of ethyl acetate, 160 parts of peracetic acid was added dropwise as an ethyl acetate solution at 50 ° C. over 4 hours, and the mixture was aged at 50 ° C. for 2 hours. After removing acetic acid, ethyl acetate and peracetic acid, it was dissolved in 500 parts of ethyl acetate at 40 ° C., followed by washing with 250 parts of distilled water 5 times, and then ethyl acetate was removed.
Dissolved in 80 parts of methyl isobutyl ketone, solid content 80%,
A compound (E) having an epoxy equivalent of 65 was obtained. Compound (D)
225 parts, compound (E) 163 parts, aluminum acetylacetonate 0.2 parts and trimethylolpropane 1
Add 0 parts and hold at 100 ° C for 1 hour, then at 150 ° C for 3 hours.
After reacting for a time, ethylene glycol monobutyl ether 60
Add parts and cool. Solid content 70%, epoxy equivalent 21
A curing resin (II-) of 0 is obtained. The number average molecular weight of the resin was about 1,100.

Curing Resin (II-) 33.4 parts of METHB (3,4-epoxycyclohexylmethyl methacrylate) dissolved in 2 parts of azobisdimethylvaleronitrile were mixed with 10 parts of methyl isobutyl ketone heated to 100 ° C. Add dropwise to a mixed solvent with 10 parts of butyl cellosolve over 2 hours, and age for 1 hour.
The temperature was raised to 5 ° C. and the mixture was aged for 1 hour to obtain 54 parts of a curable resin (II-) solution having a solid content of 60% and an epoxy equivalent of 196. The number average molecular weight of the resin was about 10,000.

Curing resin (II-) A mixture of 32.0 parts of METHB monomer and 8.0 parts of hydroxyethyl acrylate and 2.4 parts of azobisdimethylvaleronitrile dissolved in butyl cellosolve 24 heated to 100 ° C. Drop over 2 hours, then 1
After ageing, the temperature was raised to 125 ° C. and further ageing for 1 hour to obtain 64.8 parts of a curing resin (II-) having a solid content of 60% and an epoxy equivalent of 245. The number average molecular weight of the resin was about 12,000.

Curing resin (II-) 3,4-epoxycyclohexylmethyl acrylate 3
2.4 parts of azobisdimethylvaleronitrile was dissolved in a mixture of 7 parts and 3 parts of hydroxyethyl acrylate, and the same treatment as the curing resin (II-) was performed.
Curing resin having a solid content of 60% and an epoxy equivalent of 200 (II-
) Got. The number average molecular weight of the resin was about 15,000.

I-3 A hydrolyzable alkoxysilane group
Production Example 1 of Epoxy Resin Amine Adduct Containing Epoxy resin amine adduct containing a hydrolyzable alkoxysilane group was produced with the following formulation.

Raw material parts by weight Epon 828EL ¹⁾ 1,045 Bisphenol A 171 Diethanolamine 52.2 KBE-903 ²⁾ 221 Diethanolamine 157.5 Ethylene glycol monobutyl ether 706 Note 1) Diglycidyl ether of bisphenol A having an epoxy equivalent of about 190 (Yukaka Shell Co., Ltd.) Note 2) γ-aminopropyltriethoxysilane (Shin-Etsu Chemical Co., Ltd.) Nitrogen gas was added to a reaction vessel equipped with a thermometer, a stirrer, a reflux condenser and a nitrogen gas blowing port. Epon 8 under blowing
28 EL, bisphenol A and diethanolamine were charged and heated to 120 ° C. and reacted until the epoxy equivalent ³⁾ reached the theoretical value (317). Then cool to 80 ° C., add KBE-903 and diethanolamine,
The reaction was continued until the tertiary amine value ⁴⁾ reached the theoretical value (102). Then, the mixture was diluted with ethylene glycol monobutyl ether to obtain an ethylene glycol monobutyl ether solution having a solid content of 70% of an epoxy resin amine adduct containing a hydrolyzable alkoxysilane group having a number average molecular weight of about 1,650.

Note 3) According to JIS K-7236. However, the amino group is also added as an epoxy group.

Note 4) After acetylation with acetic anhydride, titration with perchloric acid using crystal violet as an indicator.

Production Example 2 An epoxy resin amine adduct containing a hydrolyzable alkoxysilane group was produced with the following formulation.

Raw material parts by weight Epon 828EL 950 Bisphenol A 342 Diethanolamine 52.5 X-12-636 ⁵⁾ 289.5 Ethylene glycol monobutyl ether 700 Note 5) N-methyl-γ-aminopropyltrimethoxysilane (Shin-Etsu Chemical Co., Ltd. )) Epon 828EL, bisphenol A and diethanolamine were charged into a reactor similar to that of Production Example 1 while blowing nitrogen gas, heated to 120 ° C., and reacted until the epoxy equivalent ³⁾ reached the theoretical value (672). Then, it cooled to 80 degreeC, X-12-636 was added, and it was made to react until the tertiary amine value reached a theoretical value (69). Then, it was diluted with ethylene glycol monobutyl ether to obtain a solution having a solid content of 70% of an epoxy resin amine adduct containing a hydrolyzable alkoxysilane group having a number average molecular weight of about 1,600.

Production Example 3 An epoxy resin amine adduct containing a hydrolyzable alkoxysilane group was produced with the following formulation.

Raw material parts by weight Epon 828 EL 950 Bisphenol A 342 Amine A ⁶⁾ 96.5 Amine A (post-added) 193 Amine B ⁷⁾ 159 Deionized water 36 KBE-402 ⁸⁾ 496 Ethylene glycol monobutyl ether 486 Note 6) Effective A methyl isobutyl ketone solution of ketimine with 74% monoethanolamine and methyl isobutyl ketone.

Note 7) Methyl isobutyl ketone solution of diethylenetriamine of 84% active ingredient in methyl isobutyl ketone of diketimine.

Note 8) γ-glycidoxypropylmethyldiethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.) Epon 828EL, bisphenol A and amine A were charged into a reactor similar to that in Production Example 1 under nitrogen gas blowing to prepare 160 Heat to ℃, epoxy equivalent ³⁾ theoretical value (69
It was made to react until it reached 4). Then, the mixture was cooled to 100 ° C., amine A (post-added) and amine B were added, and the reaction was continued until the tertiary amine value reached the theoretical value (97). After that, deionized water was added at 100 ° C. to carry out a deketimination reaction, and subsequently, KBE-402 was added at 100 ° C. to react until the epoxy group was eliminated. Then, it was diluted with ethylene glycol monobutyl ether to obtain a solution having a solid content of 70% of an epoxy resin amine adduct containing a hydrolyzable alkoxysilane group having a number average molecular weight of 1,900.

I-4 Production of Gelled Fine Particles Production Example 4 100 parts of the epoxy resin amine adduct containing the hydrolyzable alkoxysilane group obtained in Production Example 1 and 11 parts of 10% acetic acid were added to a 21-flask, and the mixture was added to 30 flasks. After stirring at 50 ° C. for 5 minutes, 239 parts of deionized water was added dropwise over about 30 minutes while stirring strongly, and the temperature was raised to 50 ° C. and stirring was performed for about 3 hours.

Thus, a milky white intraparticle crosslinked gelled fine particle (G-) dispersion having a solid content of 20% was obtained, and the average particle diameter of the fine particles in ethylene glycol monobutyl ether was 0.15 μm.

Production Example 5 100 parts of the epoxy resin amine adduct containing the hydrolyzable alkoxysilane group obtained in Production Example 2 and 7.5 parts of 10% acetic acid were added to a 21 flask and stirred at 30 ° C. for 5 minutes. Thereafter, 242.5 parts of deionized water was added dropwise over about 30 minutes while stirring vigorously, the temperature was raised to 50 ° C., and stirring was performed for about 3 hours.

Thus, the solid content is 20%, the average particle size in ethylene glycol monobutyl ether is 0.15 μm.
A milky white intra-particle cross-linked gelled fine particle (G-) dispersion was obtained.

Production Example 6 To a 21-flask was added 100 parts of the epoxy resin amine adduct containing the hydrolyzable alkoxysilane group obtained in Production Example 3 and 11 parts of 10% acetic acid, and the mixture was stirred at 30 ° C. for 5 minutes. 239 parts of deionized water was added dropwise over about 30 minutes with strong stirring, the temperature was raised to 50 ° C., and stirring was carried out for about 3 hours.

Thus, the solid content is 20% and the average particle size in ethylene glycol monobutyl ether is 0.15 μm.
A milky white intra-particle cross-linked gelled fine particle (G-) dispersion was obtained.

Production Example 7 1 equipped with a stirrer, thermometer, cooling tube and heating mantle
(3) A flask was charged with 3,507.5 parts of deionized water and 80 parts of Latemur K-180 (manufactured by Kao Corporation, 25% aqueous solution), and heated to 90 ° C with stirring. A polymerization initiator VA-086 (manufactured by Wako Pure Chemical Industries, Ltd.)
20 percent of an aqueous solution mixture of 12.5 parts dissolved in 500 parts deionized water was added. After 15 minutes, 5 percent of the following monomer mixture was added. Styrene 430 parts n-Butyl acrylate 440 parts 1,6-hexanediol diacrylate 40 parts 2-hydroxyethyl acrylate 40 parts KBM-503 ^* 50 parts * γ-methacryloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.)

Then, after stirring for another 30 minutes, dropping of the remaining monomer mixture and polymerization initiator aqueous solution was started. The monomer mixture was supplied for 3 hours, and the polymerization initiator aqueous solution was supplied for 3, 5 hours, respectively, and the polymerization temperature was kept at 90 ° C. After the dropping of the aqueous solution of the polymerization initiator, the mixture was heated for 30 minutes and kept at 90 ° C., cooled to room temperature, filtered with a filter cloth, and taken out. Thus, solid content 20%, average particle size 0.0
A 7 μm gelled fine particle (G-) dispersion was obtained. (See Japanese Patent Laid-Open No. 2-47173)

I-5 Preparation of Pigment Paste To 12.5 parts of the base resin is added 4.4 parts of 10% formic acid and 15 parts of deionized water is added with stirring. Further titanium white 10
Parts, 10 parts of clay, 1 part of carbon, and 2 parts of basic lead silicate were added and dispersed in a ball mill for 24 hours, and 11 parts of deionized water was added to obtain a pigment paste (P-1) having a solid content of 50%. The same base resin as that used in each production example shown in Table 1 was used. In the pigment paste (P-1), all the pigment components were 15 parts of clay, Syloid 244 (a water-containing amorphous silicon dioxide pigment manufactured by Fuji Devison Co., Ltd., an oil absorption of 3).
00) 27 parts, carbon 2 parts, and graphite (flake-shaped graphite manufactured by Chuetsu Graphite Co., Ltd.) 5 parts, to obtain a pigment paste (P-2) having a solid content of 64.2% in the same manner.

I-6 Preparation of Cationic Electrodeposition Paint (A-1) Base resin (I) obtained in the above Production Example, curing resin (II),
A cationic electrodeposition coating material (A-1) was prepared using the gelled fine particles and the pigment paste. That is, the base resin (I) and the curing resin (II) were mixed at the compounding amounts shown in Table 1 (all of which are shown as solid content) and solid content was 20% with deionized water.
After that, gelled fine particles, pigment paste, etc. were further added, and deionized water was added to obtain each cation electrodeposition bath having a solid content of 20%. In Table 1, pH of electrodeposition bath
Was prepared with a 10% formic acid aqueous solution.

[0191]

[Table 1]

I-7 Preparation of Cationic Electrodeposition Coating (A-2) After the following components (1) to (3) were combined and reacted at 150 ° C. for 2 hours, the components (2) were mixed and reacted at 80 to 90 ° C. for 3 hours to give a solid. A base resin (I-) having a content of 75% was obtained.

Bisphenol-type epoxy resin (“Araldite # 6071” manufactured by Ciba-Geigy) 930 parts Bisphenol-type epoxy resin (“Araldite GY2600” manufactured by Ciba-Geigy) 380 parts Polycaprolactone diol (“Plaxel # 205” manufactured by Daicel) 550 parts Dimethyl Benzylamine acetate 2.6 parts p-Nonylphenol 79 parts Monoethanolamine methyl isobutyl ketone ketiminide 71 parts Diethanolamine 105 parts Butylcellosolve 180 parts Cellosolve 525 parts

Next, 5.73 parts, titanium white 14.5 parts, carbon 0.54 parts, and clay 7.0 were prepared by quaternary chlorination of the above base resin (I-) to adjust the solid content to 60%.
Parts, 2.3 parts lead silicate, 2.0 dibutyltin oxide
Part and deionized water (27.49 parts) to prepare a pigment paste (P-3) having a solid content of 50%.

The base resin (I-) was mixed with diisocyanate and the like in the amounts shown in Table 2, gelled fine particles and pigment paste (P-3) were further added, and deionized water was added. Each cation electrodeposition bath having a solid content of 20% was prepared. In Table 2, the pH of the electrodeposition bath is 10%
It was adjusted with an aqueous acetic acid solution.

I-8 Preparation of Cationic Electrodeposition Paint (A-3) The cationic electrodeposition paint (A-3) was prepared by changing the diisocyanate in the composition shown in Table 2 in the preparation of the above cationic electrodeposition paint (A-2). Except for the above, it was prepared in the same manner as (A-2).

[0197]

[Table 2]

I-9 Preparation of Primer (B) Polybutylene adipate (number average molecular weight 2,000) 2
30 g, polycaprolactone diol (number average molecular weight of 2,000) 230 g, dimethylolpropionic acid 46
3., 13 g of 1,4-butanediol and 240 g of isophorone diisocyanate were reacted to obtain an NCO content of 4.
0% of terminal NCO prepolymer was obtained. Next, 330 g of acetone was added to the obtained prepolymer and dissolved uniformly, 31 g of triethylamine was added with stirring, and 1,200 g of ion-exchanged water was further added to obtain 5 parts of the obtained aqueous dispersion.
After maintaining at 0 ° C. for 2 hours to complete the water elongation reaction, acetone was distilled off under reduced pressure to obtain a polyurethane emulsion having a solid content of 42%. This was used as a primer (B-1). Further, a resin (static glass transition temperature −43 ° C.) in which a propylene-ethylene copolymer was graft-polymerized with maleic acid was diluted with an organic solvent to obtain a primer (B-2).

I-10 Preparation of organic solvent-based intermediate coating composition (C-1) In a reaction vessel, 59.2 parts of phthalic anhydride, 23.1 parts of hexahydrophthalic anhydride, 51.1 parts of adipic acid and trimethylolpropane were placed. After charging 27.3 parts and neopentyl glycol 84 parts and reacting at 230 ° C. for 5 hours while removing condensed water generated by heating, solid content 60% in a mixed solvent of xylene / swazol 1000 = 50/50. To obtain a polyester resin solution having a hydroxyl value of 101 and a molecular weight of 5,400. The above polyester resin solution, amino resin, alicyclic epoxy compound and the like are blended,
Organic solvent type intermediate coating composition (C-1-
)-(C-1-) was created.

[0200]

[Table 3]

I-11 Preparation of Water-based Intermediate Coating Material (C-2) A water-based intermediate coating material (C-2-) was prepared by the following formulation.

[0201] (* 1) Polyester: Phthalic anhydride / isophthalic acid / adipic acid / trimethylolpropane / 0.1 0.35 0.5 0.25 neopentyl glycol 0.75 (molar ratio) was added to the reaction vessel at 200 ° C. After reacting for 5 hours, 0.05 mol of phthalic anhydride was added and further reacted at 130 ° C. for 1 hour to obtain a polyester resin having a number average molecular weight of 4,800, an acid value of 30, and a hydroxyl value of 55.

(* 2) Amino resin: Mitsui Cyanamide Co., Ltd., Cymel 370 (* 3) Titanium white: Teikoku Kako Co., Ltd. JR-602 (trade name) Carbon black: Mitsubishi Kasei Co., Ltd. Black M-100

In the above formulation, EHPE-315
Use of 3,4-epoxycyclohexylcarboxymethylcyclohexene oxide instead of 0 (C-
2-), and EHPE-3150 was not mixed, and the same solid content (C-2-) was prepared in the same manner as above.

II Examples and Comparative Examples The cationic electrodeposition bath obtained in the above Production Example was adjusted to a bath temperature of 30 ° C., and zinc phosphate treated steel sheet (0.8 × 150 × 70 mm)
Was dipped, and electrodeposition coating was performed at 200 to 300 V for 3 minutes so as to obtain a film thickness of 20 to 25 μm (dry film thickness). Then, after pulling up the coated plate and washing with water to remove water droplets, or after removing water droplets and further draining and drying at 100 ° C. for 10 minutes, the primer (B) is applied to the uncured electrodeposition coated surface.
Is spray-coated so as to have a film thickness of 10 μm (dry film thickness), preheated at 80 ° C. for 5 minutes, and then the intermediate coating composition obtained in the above Production Example is viscously coated on the uncured coating surface. Spray coating to a film thickness of 25-30 μm (dry film thickness),
The three-layer coating film was heated at 160 ° C. for 30 minutes to be simultaneously cured (3 coat 1 bake system). However, in Example 17, the above-mentioned intermediate coating was not performed, and the after-mentioned top coating was directly coated on the primer coating surface to finish as 3 coats 1 bake. In Comparative Example 5, a two-coat one-bake system of an electrodeposition coating film and an intermediate coating film was used. In Comparative Example 6, the electrodeposition coating film was cured by heating at 160 ° C. for 30 minutes, and then a primer and an intermediate coating composition were applied. After coating, both coatings were heat-cured at 160 ° C. for 30 minutes (3 coat 2 bake method). The finish of the obtained intermediate coating surface was evaluated.

Furthermore, on the above coating film (excluding Example 17)
Topcoat paint "Amilak Black" (made by Kansai Paint Co.,
Melamine / polyester organic solvent type thermosetting paint) to a film thickness of 40 to 45 μm (dry film thickness),
A coated plate was obtained by heating and curing at 140 ° C. for 30 minutes. Table 4 below shows the performance test results of the electrodeposition paint type, the primer paint type, the intermediate coating type used in each of the examples and the comparative examples, and the formed multilayer coating film.

[0207]

[Table 4]

The performance test method in Table 4 above is as follows. (* 1) Heat loss: The weight of the steel sheet is W _0, and each cationic electrodeposition coating is applied to this steel sheet at 30 ° C. to a film thickness of 20 to 25 μm.
After cationic electrodeposition at 200 to 300 V for 3 minutes so as to be m, the coated surface is washed with water by pulling up from the electrodeposition bath, and then at 105 ° C. for 3 minutes.
The coating film weight (Y) was measured after heating for a long time to remove all or most of the water content in the coating film, and then the coating film was heated at 170 ° C. for 20 minutes to three-dimensionally crosslink and cure the coating film, and The film weight (Z) was measured. These measured values were applied to the following equation to determine the heat loss on electrodeposition coating film (X).

[Equation 2]

(* 2) Melt viscosity of coating film: The melting viscosity of the electrodeposition coating film when the electrodeposition plate pulled out from the bath was heated at 160 ° C. in the same manner as in (* 1) above, was measured by a ball-ball type viscosity. Law (JIS
-Z-0237), and evaluated from the heat flow appearance of scratches. The numerical value indicates the lowest viscosity (centipoise).

(* 3) Finishing property of intermediate coated surface: Electrodeposition coating Visual inspection of appearance such as smoothness and sharpness of intermediate coated surface obtained by simultaneous curing of primer coating and intermediate coating. evaluated. ⊚: Good, ○: No dents, dents, etc., but the sharpness of the image is slightly deteriorated, ∆: Slight dents, dents, etc., ×: Many.

(* 4) Finishing property of top-coating surface: Finishing properties such as smoothness, gloss, and sharpness of the coating surface after top-coating were comprehensively evaluated visually. ◎: good, ○: almost good, △:
Somewhat bad.

(* 5) Chipping resistance: Using a stepping stone tester (Suga Tester Co., Ltd., JA-400 type), a coated plate was vertically mounted on a sample holder of the tester, and 250 g of 6 was used.
The crushed stone is sprayed with a pressure gauge of the same tester at an air pressure of 4 kg / cm ² , and the crushed stone is made to collide vertically with the coated plate. The degree of peeling damage at that time is evaluated according to the following criteria. ⊚ (Good): Slight scratches are observed on a part of the top coat film. ○ (Slightly good): Slight scratches are observed on the electrodeposition coating film and a part of the topcoat and intermediate coating film. Δ (Slightly bad): Significant scratches are observed on the electrodeposition coating film and the top coating and intermediate coating film. X (Poor): Peeling of the electrodeposition coating film at the impacted area and very large scratches and peeling on the topcoat and intermediate coating film are observed.

(* 6) Adhesiveness: Goggles (1 × 1 mm1
(00) Cellophane adhesive tape test. ○ means no peeling.

(* 7) Moisture resistance: temperature 50 ° C., relative temperature 9
After leaving for 5 days in a blister box of 8 to 100% RH, it was taken out and examined for blisters. ○ indicates no blisters,
Δ indicates that blister is slightly generated.

(* 8) Edge Covering Property: A steel plate having an edge angle of 45 ° was electrodeposited under the condition that the cured film thickness of the flat portion was 20 μm, and then primer coating and intermediate coating were performed (Example 17). Is a top coat) It is cured under the prescribed baking conditions, set in a salt spray device so that the edges of the test plate become vertical, and the salt water temperature is set to 50 ° C by the JIS-Z-2371 salt water spray test for 168 hours. The corrosion resistance of the rear edge portion is evaluated. ◎: No rusting occurred ○: Slight rusting occurred △: Rusting occurred considerably ×: Rusted edge surface

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Sadaji Katayama 4-17-1, Higashi-Hachiman, Hiratsuka-shi, Kanagawa Kansai Paint Co., Ltd.

Claims (7)

[Claims] 1. A uncured coating film surface coated with a cationic electrodeposition coating material is coated with a chipping-resistant primer, and then an intermediate coating material or a top coating material is coated, and the three-layer coating film is simultaneously cured to obtain a composite coating. A method for forming a layer coating film, wherein the cationic electrodeposition coating composition is a coating composition in which the coating film weight loss upon heat curing of the electrodeposition coating film from which water is removed is 10% by weight or less, and the cationic electrodeposition composition A method for forming a coating film, characterized in that the coating film obtained from the coating composition has a minimum melt viscosity during curing of 10 ⁴ to 10 ⁸ cps. 2. The cationic electrodeposition coating material contains a resin (I) containing a hydroxyl group and a cationic group, and an epoxy group containing an alicyclic skeleton and / or a bridged alicyclic skeleton to which an epoxy group is bound. The coating film forming method according to claim 1, which contains, as a main component, an epoxy resin (II) having an average of two or more functional groups per molecule. 3. The cationic electrodeposition paint mainly comprises a resin (I) containing a hydroxyl group and a cationic group, and a blocked polyisocyanate compound (III) using a low molecular weight compound having a molecular weight of 130 or less as a blocking agent. The coating film forming method according to claim 1, which is contained as a component. 4. The method for forming a coating film according to claim 1, wherein the cationic electrodeposition coating material contains gelled fine particles. 5. The coating according to claim 4, wherein the gelled fine particles are cationic electrodepositable gelled fine particles obtained by dispersing an epoxy resin amine adduct containing a hydrolyzable alkoxysilane group in water and crosslinking the particles. Film forming method. 6. The coating film formation according to claim 1, wherein the anti-chipping primer is a barrier coat containing a modified polyolefin resin as a main component, wherein the formed coating film has a static glass transition temperature of −30 to −60 ° C. Method. 7. The method of forming a coating film according to claim 1, wherein the anti-chipping primer is an aqueous primer containing a polyurethane emulsion obtained by chain elongation of a carboxyl group-containing polyurethane prepolymer in the presence of an aqueous medium.