JP2002294173A - Cationic electrodeposition coating material composition and method for forming coating film by using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a cationic electrodeposition coating material composition which contains a resin composition having sulfonium group and propargyl group and which forms a coating film having good oil repellency, and to provide a method for forming a coating film by using the same. SOLUTION: The cationic electrodeposition coating material composition contains a resin composition having sulfonium group and propargyl group, and crosslinked resin particles obtained by subjecting an α,β-ethylenically unsaturated monomer mixture to emulsion polymerization by using an emulsifier comprising an acrylic resin having ammonium group, wherein the content of the crosslinked resin particles is 3-20 wt.% based on the coating resin solids. It is desirable that the ratio of the solids of the acrylic resin having the ammonium group to the α,β-ethylenically unsaturated monomer mixture is (90:10) to (75:25).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a cationic electrodeposition coating composition, and more particularly to a cationic electrodeposition coating composition containing crosslinked resin particles and a method for forming a coating film using the same.

[0002]

2. Description of the Related Art The coating process of automobile bodies and parts is performed by
In general, for a subject to be subjected to a chemical conversion treatment with a phosphate or the like, an undercoating with an electrodeposition paint is performed, and then, if necessary, an intermediate coat, and further a top coat are sequentially applied and obtained. Consists of sequentially heating and curing the coating film,
A multi-layer coating is formed on an object to be coated.

[0003] Electrodeposition paints used as undercoat paints are roughly classified into cationic and anionic paints. Cationic paints have been suitably used in view of the anticorrosive properties of the resulting coating films. JP-A-2000-38525 discloses a cationic electrodeposition coating composition containing a resin composition having a sulfonium group and a propargyl group for the purpose of improving throwing power.

[0004] By the way, even if the object to be coated has been degreased or chemically treated, it remains on the object to be coated or exists in the coating process inside or outside the press oil, rust preventive oil, machine oil, etc. May be contaminated on the surface with oils and fats. If the electrodeposition coating is applied while being contaminated, in the subsequent heating process, the fats and oils boil by heating,
There is a possibility that a phenomenon called so-called bumping oil cissing which causes pinholes on the obtained electrodeposition coating film may occur. When pinholes are generated in this manner, not only the appearance of the multilayer coating film due to the unevenness of the pinholes, but also the anticorrosion property may be reduced due to incomplete coating.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a cationic electrodeposition coating composition containing a resin composition having a sulfonium group and a propargyl group, which has good oil repellency at the time of forming a coating film, and uses the same. It is an object of the present invention to provide a method for forming a coated film.

[0006]

According to the present invention, an α, β-ethylenically unsaturated monomer mixture is emulsion-polymerized using a resin composition having a sulfonium group and a propargyl group and an acrylic resin having an ammonium group as an emulsifier. And a crosslinked resin particle obtained by the above method, wherein the content of the crosslinked resin particle is 3 to 20% by weight based on the solid content of the coating resin. It is an electrodeposition coating composition. Here, the ratio of the resin solid content of the acrylic resin having an ammonium group to the α, β-ethylenically unsaturated monomer mixture is 90/10 to 7
It is preferably 5/25.

Further, an α, β-ethylenically unsaturated monomer mixture contains two α, β-ethylenically unsaturated bonds in a molecule.
It is preferable to contain 5 to 20% by weight of a poly (meth) acrylate having at least one acrylic resin, and the number of ammonium groups in the acrylic resin having an ammonium group is preferably 2 to 15 per molecule.

Further, it is preferable that the acrylic resin having an ammonium group is obtained by adding a tertiary amine compound and an organic acid to the acrylic resin having an epoxy group to quaternize the acrylic resin. The number average molecular weight of the acrylic resin is more preferably 5,000 to 20,000.

The resin composition having a sulfonium group and a propargyl group has a sulfonium group content of 5 to 400 m per 100 g of the resin solid content in the cationic electrodeposition coating composition.
mol and propargyl groups in an amount of 10 to 495 mmol, and the total content of sulfonium groups and propargyl groups is preferably 500 mmol or less, and is made of a resin having a novolak phenol type epoxy resin or a novolak cresol type epoxy resin as a skeleton. And having a number average molecular weight of 700 to 5000, containing 5 to 250 mmol of sulfonium groups and 20 to 395 mmol of propargyl groups per 100 g of solid content of the resin composition, and having a total content of sulfonium groups and propargyl groups. More preferably, it is 400 mmol or less.

Further, the present invention provides a step (1) of forming an electrodeposited film by electrodepositing the above-mentioned cationic electrodeposition coating composition on an object to be coated, and an electrodeposited film obtained by the step (1). (2) washing the electrodeposited film with water, and (3) heating the water-washed electrodeposited film obtained in the step (2) to form an electrodeposited film. .

Further, the present invention is an object to be coated having a coating film obtained by the above coating film forming method.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The cationic electrodeposition coating composition of the present invention contains crosslinked resin particles. The crosslinked resin particles are obtained by emulsion polymerization of an α, β-ethylenically unsaturated monomer mixture using an acrylic resin having an ammonium group as an emulsifier.

The α, β-ethylenically unsaturated monomer mixture usually contains a poly (meth) acrylate having at least two α, β-ethylenically unsaturated bonds in a molecule in order to crosslink resin particles. In. Its content is 5 to 15% by weight in the monomer mixture. When the content is less than 5% by weight, the crosslinking of the resin particles does not sufficiently proceed, and when it exceeds 15% by weight, the crosslinking of the resin particles proceeds too much, and the physical properties of the obtained coating film may be deteriorated. There is.

As the poly (meth) acrylate having two or more α, β-ethylenically unsaturated bonds in the molecule, a poly (meth) acrylate having a structure in which a plurality of (meth) acrylic acids are ester-bonded to a divalent or higher alcohol. Such as ethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, tri (meth) acryl Trimethylolpropane acid and the like can be mentioned. These may be two or more kinds.

The α, β-ethylenically unsaturated monomer mixture contains a general α, β-ethylenically unsaturated monomer in addition to the poly (meth) acrylate. Examples of such general α, β-ethylenically unsaturated monomers include those having a reactive functional group and those having no reactive functional group. Α, β- having the above reactive functional group
Specific examples of the ethylenically unsaturated monomer include hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, allyl alcohol, methacryl alcohol, and hydroxyethyl (meth) acrylate. And those having an epoxy group such as glycidyl (meth) acrylate such as adducts of ε-caprolactone and ε-caprolactone. Α, β- having the above reactive functional group
If an ethylenically unsaturated monomer is included in the mixture, it is more preferred that the amount is no more than 20% by weight of the mixture. Further, the hydroxyl value or the epoxy value of the mixture at that time is preferably 20 or less.

On the other hand, examples of the α, β-ethylenically unsaturated monomer having no reactive functional group include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, and (meth) acrylate. Isopropyl acrylate,
N-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, isobornyl (meth) acrylate, methacrylic acid (Meth) acrylates such as cyclohexyl, t-butylcyclohexyl (meth) acrylate, dicyclopentadienyl (meth) acrylate, dihydrodicyclopentadienyl (meth) acrylate; (meth) acrylamide, N- Methylol (meth) acrylamide, N-
Butoxymethyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-dibutyl (meth) acrylamide, N, N-dioctyl (meth) acrylamide, N-monobutyl (meth) acrylamide,
N-monooctyl (meth) acrylamide, 2,4-dihydroxy-4′-vinylbenzophenone, N- (2-
Polymerizable amide compounds such as hydroxyethyl) acrylamide and N- (2-hydroxyethyl) methacrylamide; styrene, α-methylstyrene, vinyl ketone, t
Polymerizable aromatic compounds such as butylstyrene, parachlorostyrene and vinylnaphthalene; polymerizable nitriles such as acrylonitrile and methacrylonitrile; ethylene, propylene and the like), vinyl esters (for example, α- such as vinyl acetate and vinyl propionate). Olefin; diene such as butadiene and isoprene;

The glass transition temperature of the α, β-ethylenically unsaturated monomer mixture is preferably from 40 to 100 ° C., and more preferably from 40 to 80 ° C.
When the glass transition temperature is less than 40 ° C., the effect of the present invention may be insufficient, and when it exceeds 100 ° C., the appearance of the coating film may be deteriorated. The glass transition temperature of the α, β-ethylenically unsaturated monomer mixture in the present specification is determined by calculation based on the mixing ratio using the glass transition temperature of each α, β-ethylenically unsaturated monomer. be able to.

The solubility parameter of the α, β-ethylenically unsaturated monomer mixture is preferably from 10 to 12, and more preferably from 10 to 11. If the solubility parameter is less than 10, there is a possibility that the adhesion with the immediately above coating film such as an intermediate coating film is reduced,
If it exceeds 12, the desired crosslinked resin particles may not be obtained. The solubility parameter in the present specification can be determined by a method well known to those skilled in the art such as a turbidity method.

On the other hand, the acrylic resin having an ammonium group used as an emulsifier in the emulsion polymerization for obtaining the crosslinked resin particles preferably has 2 to 15 ammonium groups per molecule. When the number is less than 2 per molecule, the dispersion stability may be reduced. When the number is more than 15, the water resistance of a coating film obtained when used in a cationic electrodeposition coating composition is reduced. There is fear.

The above-mentioned acrylic resin having an ammonium group can be obtained by various methods. However, it can be easily obtained by adding a tertiary amine compound and an organic acid to the acrylic resin having an epoxy group to obtain a quaternary resin. Can be. The quaternization may be performed by previously mixing a tertiary amine compound and an organic acid, and adding this mixture as a quaternizing agent to an acrylic resin having an epoxy group.

The acrylic resin having an epoxy group used for quaternization includes an α, β-ethylenically unsaturated monomer having an epoxy group such as glycidyl (meth) acrylate and the above-mentioned other α, β-ethylenically unsaturated monomers. It can be obtained by polymerizing a monomer mixture comprising a monomer by a conventional method. In this quaternization method, the epoxy group is opened with a tertiary amine to form an ammonium group. Therefore, the amount of the α, β-ethylenically unsaturated monomer having an epoxy group is determined according to the number of the above-mentioned ammonium groups. Can be determined.

The glass transition temperature of the monomer mixture used for obtaining the acrylic resin having an epoxy group is preferably 10 to 40 ° C., and 10 to 25 ° C.
Is more preferable. The above glass transition temperature is 1
If the temperature is lower than 0 ° C., the effect of the present invention may be insufficient, and if it is higher than 40 ° C., the appearance of the coating film may be deteriorated.

The solubility parameter of the monomer mixture used to obtain the acrylic resin having an epoxy group is preferably 9-12. If the solubility parameter is less than 9, the adhesion to the immediately above coating film such as an intermediate coating film may be reduced, and if it exceeds 12, the desired resin may not be obtained.

The epoxy resin having an epoxy group preferably has a number average molecular weight of 5,000 to 20,000. If the number average molecular weight is less than 5,000, the effect of the present invention may be insufficient, and if it is more than 20,000, a problem of an increase in the viscosity of the emulsifier may occur.

On the other hand, as the tertiary amine compound for introducing an ammonium group into the acrylic resin, various compounds such as trimethylamine, triethylamine, tributylamine, trioctylamine, dimethylethanolamine and methyldiethanolamine can be used. The amount of the tertiary amine compound can be determined according to the amount of the ammonium group to be introduced.

Organic acids used for quaternization include formic acid, acetic acid, lactic acid, propionic acid, boric acid, butyric acid, dimethylolpropionic acid, hydrochloric acid, sulfuric acid, phosphoric acid, N-acetylglycine, N-acetyl-β -Alanine and the like can be mentioned, but lactic acid, acetic acid, and dimethylolpropionic acid are preferred from the viewpoint of stability during emulsification.

In this quaternization, the amounts of the epoxy group, the tertiary amine compound, and the organic acid in the epoxy resin having an epoxy group are preferably 1/1/1 to 1/2 in a molar ratio. The quaternization reaction is generally performed for 2 to 10 hours, and may be heated to 60 to 100 ° C as needed.

The crosslinked resin particles contained in the cationic electrodeposition coating composition of the present invention can be obtained by carrying out emulsion polymerization using the thus obtained acrylic resin having an ammonium group as an emulsifier. Emulsion polymerization can be carried out using a generally well-known method. Specifically, an emulsifier is dissolved in water or an aqueous medium containing an organic solvent such as an alcohol if necessary, and the α, β-ethylenically unsaturated monomer mixture and the polymerization initiator are heated and stirred. It can be performed by dropping.
An α, β-ethylenically unsaturated monomer mixture previously emulsified with an emulsifier and water may be similarly added dropwise.

Preferably, the emulsifier is dissolved in an aqueous medium, and the initiator is added dropwise with heating and stirring.
β-ethylenically unsaturated monomer is dropped first, then
The remaining α, β-ethylenically unsaturated monomer mixture previously emulsified with an emulsifier and water may be added dropwise. By adopting this method, variation from the target particle diameter is reduced, and preferable crosslinked resin particles can be obtained.

As the polymerization initiator which can be suitably used here, azo oily compounds (for example, azobisisobutyronitrile, 2,2'-azobis (2-methylbutyronitrile), 2,2'- Azobis (2- (2-imidazolin-2-yl) propane) and 2,2′-azobis (2,4-dimethylvaleronitrile) and aqueous compounds (for example, anionic 4,4′-azobis (4
-Cyanovaleric acid), 2,2-azobis (N- (2-carboxyethyl) -2-methylpropionamidine) and cationic 2,2'-azobis (2-methylpropionamidine)); Oily peroxides (eg, benzoyl peroxide, parachlorobenzoyl peroxide, lauroyl peroxide, t-butyl perbenzoate, etc.), and aqueous peroxides (eg, potassium persulfate and ammonium persulfate, etc.)
Can be mentioned.

Here, an acrylic resin having an ammonium group is used as an emulsifier. Further, those commonly used by those skilled in the art and reactive emulsifiers, for example, Antox MS-60 (manufactured by Nippon Emulsifier), Eleminor JS-2 (manufactured by Sanyo Chemical Industries), Adecaria Soap NE -20 (manufactured by Asahi Denka Co., Ltd.) and Aqualon HS-10 (manufactured by Daiichi Kogyo Seiyaku) can be used in combination. Note that this reactive emulsifier does not belong to the α, β-ethylenically unsaturated monomer contained in the above monomer mixture.

Here, the weight ratio of the α, β-ethylenically unsaturated monomer mixture to the acrylic resin having an ammonium group is preferably 90/10 to 75/25, and more preferably 90/10 to 80/20. It is more preferred that there be. When the weight ratio is out of the above range, the appearance of the obtained coating film may be deteriorated.

In order to adjust the molecular weight, a mercaptan such as lauryl mercaptan and a chain transfer agent such as α-methylstyrene dimer can be used as required.

The reaction temperature is determined by the initiator. For example, the reaction temperature is preferably from 60 to 90 ° C. for an azo type initiator, and preferably from 30 to 70 ° C. for a redox type. Generally, the reaction time is between 1 and 8 hours. The amount of initiator relative to the total amount of the α, β-ethylenically unsaturated monomer mixture is generally from 0.1 to 5% by weight, preferably from 0.2 to 2% by weight.
It is.

The average particle diameter of the thus obtained crosslinked resin particles is preferably in the range of 0.05 to 0.30 μm. If the particle diameter is less than 0.05 μm, the effect of the present invention may be insufficient, and if it exceeds 0.30 μm, the appearance of the obtained coating film may be deteriorated.
The adjustment of the particle diameter can be made by, for example, adjusting the monomer composition and emulsion polymerization conditions.

The cationic electrodeposition coating composition of the present invention contains the crosslinked resin particles thus obtained in an amount of 5 to 10% by weight based on the solid content of the coating resin. When the content is less than 5% by weight, the effect of the present invention may be insufficient. When the content is more than 10% by weight, the appearance of the obtained coating film deteriorates.

In the cationic electrodeposition coating composition of the present invention, the resin constituting the resin composition as a component other than the crosslinked resin particles may have both a sulfonium group and a propargyl group in one molecule. However, it is not always necessary. For example, one molecule may have only one of a sulfonium group and a propargyl group. In this case, the resin composition as a whole has these two types of functional groups. That is, the resin composition comprises a resin having a sulfonium group and a propargyl group,
It may be a mixture of a resin having only a sulfonium group and a resin having only a propargyl group, or may be a mixture of all of them. The resin composition contained in the cationic electrodeposition coating composition has a sulfonium group and a propargyl group in such a meaning.

The resin serving as the skeleton of the resin composition in the cationic electrodeposition coating composition is not particularly limited, but an epoxy resin is preferably used. As such an epoxy resin, one having at least two or more epoxy groups in one molecule is suitably used. Specifically, an epibis-type epoxy resin, which is chain-extended with a diol, a dicarboxylic acid, a diamine, or the like, is used. Epoxidized polybutadiene; novolak phenol type polyepoxy resin; novolak cresol type polyepoxy resin; polyglycidyl acrylate; polyglycidyl ether of aliphatic polyol or polyether polyol; polyepoxy such as polyglycidyl ester of polybasic carboxylic acid Resins and the like can be mentioned. Of these, novolak phenol-type polyepoxy resins, novolak cresol-type polyepoxy resins, and polyglycidyl acrylates are preferable because they can be easily polyfunctionalized to enhance curability. Note that a part of the epoxy resin may be a monoepoxy resin.

The resin composition in the above cationic electrodeposition coating composition preferably has a number average molecular weight of 500 to 20,000. When the number average molecular weight is less than 500,
The coating efficiency during electrodeposition coating may be reduced.
If it exceeds 0000, it becomes difficult to form a good coating on the surface of the object to be coated. This number average molecular weight is
It is possible to set a preferred numerical value according to the resin skeleton of the resin composition, for example, as the resin skeleton,
When using novolak phenol type polyepoxy resin or novolak cresol type polyepoxy resin,
More preferably, it is 700 to 5000.

The sulfonium group in the resin composition in the cationic electrodeposition coating composition is a hydrated functional group of the resin composition. The sulfonium group is subjected to an electrolytic reduction reaction on the electrode and loses the ionic group when a voltage or current of a certain level or more is applied during the electrodeposition coating process, and the resin composition can be irreversibly rendered nonconductive. it is conceivable that.

The content of the sulfonium group in the resin composition in the above cationic electrodeposition coating composition is such that the content of the sulfonium group and the propargyl group described below is satisfied, and Resin solid content 1
Preferably, the amount is 5 to 400 mmol per 00 g. When the content is less than 5 mmol, sufficient throwing power and curability cannot be exhibited, and hydration and bath stability may be reduced. Also, 400mm
When it exceeds ol, the deposition of the coating film on the surface of the object to be coated may be deteriorated. The content of the sulfonium group, it is possible to set a preferable numerical value according to the resin skeleton of the resin composition, for example, as the resin skeleton, a novolak phenol type polyepoxy resin or a novolak cresol type polyepoxy resin When used, 5 to 100 g of resin solids in the cationic electrodeposition paint
250 mmol, more preferably 10-15.
More preferably, it is 0 mmol.

In the electrodeposition coating process in which the above-mentioned cationic electrodeposition coating composition is used, an electrode reaction is caused, and the generated hydroxide ion is retained by a sulfonium group, so that an electrogenerated base is contained in the electrodeposition coating. It is thought to occur. The electrogenerated base can convert a propargyl group having low reactivity by heating existing in the electrodeposited film into an allene bond having high reactivity by heating.

The propargyl group in the resin composition in the cationic electrodeposition coating composition not only functions as a curing functional group as described above, but also for the unknown reasons, but coexists with the above sulfonium group. The throwing power of the cationic electrodeposition paint can be further improved.

The content of the propargyl group in the resin composition in the above cationic electrodeposition coating composition is such that the content of the sulfonium group and the propargyl group described below is satisfied, and Resin composition 1
It is preferably 10 to 495 mmol per 00 g. If the content is less than 10 mmol, sufficient throwing power and curability cannot be exhibited, and
If it exceeds mmol, hydration stability may be adversely affected. The content of the propargyl group, it is possible to set a preferable numerical value according to the resin skeleton of the resin composition, for example, as the resin skeleton, a novolak phenol type polyepoxy resin or a novolak cresol type polyepoxy resin When used, 20 to 39 per 100 g of the resin solid content in the above cationic electrodeposition paint.
More preferably, it is 5 mmol.

The total content of sulfonium groups and propargyl groups in the resin composition in the cationic electrodeposition coating composition is preferably 500 mmol or less per 100 g of the resin composition in the cationic electrodeposition coating composition. preferable. When the content exceeds 500 mmol, there is a possibility that the resin cannot be actually obtained or the intended performance cannot be obtained. The total content of the sulfonium group and the propargyl group can be set to a preferable numerical value according to the resin skeleton of the resin composition. For example, as the resin skeleton, a novolak phenol type polyepoxy resin or a novolac cresol type When a polyepoxy resin is used, the amount is more preferably 400 mmol or less per 100 g of the resin solid content in the cationic electrodeposition coating composition.

Some of the propargyl groups in the resin composition in the cationic electrodeposition coating composition may be acetylated by a metal. Acetylide is a metal acetylenide similar to salts. The content of acetylated propargyl groups in the resin composition is preferably 0.1 to 40 mmol per 100 g of the resin composition in the cationic electrodeposition coating composition. When the content is less than 0.1 mmol, the effect of acetylide conversion may not be sufficiently exhibited, and
When the amount exceeds mmol, acetylide formation itself is difficult. The content of the acetylated propargyl group can be set to a preferable value according to the metal.

The metal contained in the acetylidized propargyl group is not particularly limited as long as it exhibits a catalytic action, and examples thereof include transition metals such as copper, silver and barium. Among them, copper and silver are preferable from the viewpoint of environmental compatibility, and copper is more preferable from the viewpoint of industrial availability. When copper is used, the content of the acetylidated propargyl group in the resin composition is 0.1 to 20 mmol per 100 g of the resin composition in the cationic electrodeposition coating composition.
It is preferred that

When the resin composition has the acetylated propargyl group, a curing catalyst can be introduced into the resin composition. In this way, there is no need to use an organic transition metal complex which is generally difficult to dissolve or disperse in an organic solvent or water, and even a transition metal can be easily introduced. On the other hand, even a transition metal compound which is hardly soluble can be freely used in a paint. Further, unlike the case where a transition metal organic acid salt is used, the organic acid salt is not removed by ultrafiltration, so that the bath management and the design range of the cationic electrodeposition coating composition are widened.

The resin composition in the cationic electrodeposition coating composition may contain a carbon-carbon double bond, if necessary. Since the carbon-carbon double bond has high reactivity, curability can be further improved.

When the resin composition in the above cationic electrodeposition coating composition contains a carbon-carbon double bond, the content thereof satisfies the contents of a propargyl group and a carbon-carbon double bond described below. And 10 to 485 mmol per 100 g of the resin composition in the cationic electrodeposition coating composition.
It is preferred that If the content is less than 10 mmol, the curability may not be sufficiently improved, and
If it exceeds 85 mmol, hydration stability may be adversely affected. The content of the carbon-carbon double bond can be set to a preferable numerical value according to the resin skeleton of the resin composition. For example, as the resin skeleton, a novolak phenol type polyepoxy resin or a novolac cresol type When a polyepoxy resin is used, 2 g per 100 g of resin solid content in the above-mentioned cationic electrodeposition paint is used.
More preferably, it is 0 to 375 mmol.

When the resin composition in the cationic electrodeposition coating composition contains a carbon-carbon double bond, the total content of the propargyl group and the carbon-carbon double bond is determined by the above-mentioned cationic electrodeposition coating composition. It is preferably from 80 to 450 mmol per 100 g of the resin composition therein. When the content is less than 80 mmol, the curability may not be sufficiently improved, and when the content exceeds 450 mmol,
There is a possibility that the deposition of the coating film on the surface of the object to be coated becomes poor, or the content of the sulfonium group becomes relatively small, and the throwing power becomes insufficient. The total content of the propargyl group and the carbon-carbon double bond can be set to a preferable numerical value according to the resin skeleton of the resin composition. For example, as the resin skeleton, a novolak phenol-type polyepoxy resin Alternatively, when a novolac cresol type polyepoxy resin is used, 100 to 395 mm per 100 g of the resin solid content in the cationic electrodeposition paint.
ol is more preferable.

When the resin composition in the cationic electrodeposition coating composition contains the carbon-carbon double bond, the total content of the sulfonium group, the propargyl group and the carbon-carbon double bond is as follows: The amount is preferably 500 mmol or less per 100 g of the resin composition in the cationic electrodeposition coating composition. When the content exceeds 500 mmol, there is a possibility that the resin cannot be actually obtained or the intended performance cannot be obtained. This sulfonium group,
The total content of the propargyl group and the carbon-carbon double bond can be set to a preferable numerical value according to the resin skeleton of the resin composition.For example, as the resin skeleton, a novolak phenol-type polyepoxy resin or When a novolac cresol type polyepoxy resin is used, the resin solid content in the above cationic electrodeposition coating composition is 100%.
More preferably, it is 400 mmol or less per g.

The resin composition in the above cationic electrodeposition coating composition is prepared, for example, by reacting an epoxy resin having at least two epoxy groups in one molecule with a compound having a functional group that reacts with an epoxy group and a propargyl group. Obtaining a resin composition having a propargyl group, and reacting a sulfide / acid mixture with a residual epoxy resin in the resin composition having a propargyl group obtained in the previous step to introduce a sulfonium group Can be more suitably produced.

If the resin composition in the above cationic electrodeposition coating composition contains a carbon-carbon double bond, if necessary, a functional group which reacts with an epoxy group in the previous step and carbon-carbon A compound having a double bond and the above compound may be used in combination.

When the resin composition in the cationic electrodeposition coating composition contains an acetylated propargyl group, the resin composition having a propargyl group obtained in the previous step may be, for example, copper, A metal compound such as a complex or a salt of a transition metal such as silver or barium may be reacted.

The resin composition in the cationic electrodeposition coating composition can be obtained according to the production method described in JP-A-2000-38525.

In the above cationic electrodeposition coating composition,
As described above, a resin composition having a sulfonium group and a propargyl group is included, and since this resin composition itself has curability, a curing agent is not necessarily required, but in order to further improve curability. May be included. Examples of such a curing agent include compounds having a plurality of at least one of a propargyl group and a carbon-carbon double bond, such as polyepoxides such as novolak phenol and pentaerythritol tetraglycidyl ether, and propargyl alcohol. Examples thereof include a compound having a propargyl group and a compound obtained by subjecting a compound having a carbon-carbon double bond such as acrylic acid to an addition reaction.

Further, the cationic electrodeposition coating composition may contain a curing catalyst in order to further improve curability. Examples of such a curing catalyst include, for example, commonly used transition metals such as nickel, cobalt, manganese, palladium, and rhodium, and typical metals such as aluminum and zinc, ligands such as cyclopentadiene and acetylacetone, and acetic acid. And the like to which a carboxylic acid or the like is bonded. The content of such a curing catalyst is preferably 0.1 to 20 mmol per 100 g of the resin composition in the cationic electrodeposition coating composition. When the curing catalyst contains, for example, copper, the curing catalyst can be used to convert a propargyl group in the resin composition into an acetylide.

The above cationic electrodeposition coating composition may further contain an amine, if necessary. By containing the amine, the conversion ratio of sulfonium groups to sulfides by electrolytic reduction in the electrodeposition process increases. The amine is not particularly limited, and examples thereof include amine compounds such as primary to tertiary monofunctional and polyfunctional aliphatic amines and aromatic amines. Among these, water-soluble or water-dispersible ones are preferable, for example, monomethylamine, dimethylamine, trimethylamine, triethylamine, propylamine, diisopropylamine,
An alkylamine having 2 to 8 carbon atoms such as tributylamine;
Monoethanolamine, dimethanolamine, methylethanolamine, dimethylethanolamine, cyclohexylamine, morpholine, N-methylmorpholine, pyridine, pyrazine, piperidine, imidazoline, imidazole and the like can be mentioned. These may be two or more kinds. Of these, hydroxyamines such as monoethanolamine, diethanolamine, and dimethylethanolamine are preferred from the viewpoint of water dispersibility. The amine can be directly incorporated into the cationic electrodeposition coating composition.

When the above-mentioned cationic electrodeposition coating composition contains the above-mentioned amine, the content thereof is preferably from 0.3 to 25 meq, preferably from 1 to 15 meq, per 100 g of the resin composition in the above-mentioned cationic electrodeposition coating composition. It is more preferred that there be. When the content is less than 0.3 meq,
When the improvement in throwing power is small and exceeds 25 meq,
The effect corresponding to the added amount cannot be obtained, and it is not economical.

The above-mentioned cationic electrodeposition coating composition can contain, in addition to the above-mentioned components, other components used in general cationic electrodeposition coating compositions. The other components are not particularly limited, and include, for example, pigments, rust preventives, pigment-dispersed resins, surfactants, antioxidants, and additives for paints such as ultraviolet absorbers.

The above-mentioned pigments are not particularly restricted but include, for example, coloring pigments such as titanium dioxide, carbon black and red iron oxide; rust-preventive pigments such as basic lead silicate and aluminum phosphomolybdate; constitutions such as kaolin, clay and talc; Pigments and the like generally used for cationic electrodeposition coatings can be mentioned. Here, since the rust preventive pigment contains a heavy metal, it is preferable that the rust preventive pigment is not contained from the viewpoint of environmental compatibility.

The rust preventive is not particularly limited, and examples thereof include non-heavy metal rust preventives such as calcium phosphite, zinc calcium phosphite, silica-supported silica, and calcium-supported zeolite. The total content of the pigment and the rust inhibitor is preferably from 0 to 50% by weight as a solid content in the cationic electrodeposition paint.

The above-mentioned pigment-dispersing resin is used for stably dispersing the above-mentioned pigment and rust inhibitor in the cationic electrodeposition coating composition. The pigment-dispersed resin is not particularly limited, and those generally used for paints can be used. Further, a resin containing a sulfonium group and an unsaturated bond in the resin may be used. Examples of such a pigment-dispersed resin containing a sulfonium group and an unsaturated bond include, for example, reacting a sulfide compound with a hydrophobic epoxy resin obtained by reacting a bisphenol-type epoxy resin with a half-blocked isocyanate. Alternatively, it can be obtained by a method in which a sulfide compound is reacted with the above resin in the presence of a monobasic acid and a hydroxyl group-containing dibasic acid.

The curing temperature of the above cationic electrodeposition coating composition is preferably set at 130 to 220 ° C. When the curing temperature is lower than 130 ° C., there is a possibility that the smoothness of the obtained electrodeposition coating film may be reduced. The appearance of the multilayer coating film obtained by applying a paint or the like may be reduced. The setting of the curing temperature can be performed by a method well known by those skilled in the art, such as adjusting the types and contents of the curing functional group, the curing agent and the curing catalyst.

The curing temperature in this specification is 3
It means the temperature for obtaining a coating film having a gel fraction of 85% by heating for 0 minutes. The measurement of the gel fraction is as follows:
For example, it is carried out by a method of calculating from the weight difference of the test coated plate before and after the test when the test coated plate is immersed in acetone and refluxed for 5 hours.

The above-mentioned cationic electrodeposition coating composition can be obtained by mixing the above-mentioned resin composition and the above-mentioned crosslinked resin particles with the above-mentioned components, if necessary, and dissolving or dispersing them in water. When the cationic electrodeposition coating composition is used for electrodeposition coating, the cationic electrodeposition coating composition is preferably prepared so as to be a solution having a nonvolatile content of 10 to 30%.

In the method for forming a coating film of the present invention, a step (1) of forming an electrodeposited film by electrodepositing the above-mentioned cationic electrodeposition coating composition on an object to be coated, and an electrodeposition obtained by the step (1). The method includes a step (2) of washing the electrodeposited film with water and a step (3) of heating the electrodeposited film washed with water.

Step (1) The above step (1) is to form an electrodeposition film by electrodepositing a cationic electrodeposition coating containing a resin composition having a sulfonium group and a propargyl group on an object to be coated. is there.

The object to be coated is not particularly limited, and examples thereof include those which do not deteriorate by being subjected to cationic electrodeposition coating or heating, for example, iron plates, steel plates, aluminum plates, molded products, and surface-treated products thereof. be able to.

Step (1) in the coating film forming method of the present invention
Is usually performed by applying a voltage of 50 to 450 V between an anode and an anode. When the applied voltage is less than 50 V, electrodeposition becomes insufficient and
If it exceeds 50 V, power consumption increases, which is uneconomical. When a voltage within the above range is applied using the above-mentioned cationic electrodeposition coating composition, a uniform electrodeposition film is formed on the whole object without causing a sudden increase in film thickness in the electrodeposition process. Can be. When the above voltage is applied, the solution temperature of the cationic electrodeposition paint is usually 10 to 45.
° C.

The electrodeposition coating is performed by dipping the object in the cationic electrodeposition coating composition, applying a voltage between the object and the anode using the object as a cathode, and depositing a film. Preferably, the method further comprises a step of increasing the electric resistance per unit volume of the coating by further applying a voltage to the coating. The voltage application time varies depending on the electrodeposition conditions, but generally ranges from 2 to
It can be 4 minutes.

Step (2) Step (2) in the coating film forming method of the present invention is to wash the electrodeposited film obtained in the above step (1) with water.
This water washing removes excess electrodeposition paint adhering on the electrodeposition film and the object to be coated obtained in the above step (1). Such rinsing is usually performed for about 30 seconds, for example, by immersing the object in a water tank filled with water, spraying the object with water, or the like.

Step (3) Step (3) in the coating film forming method of the present invention is to form the electrodeposited film by heating the water-washed electrodeposited film obtained in the above step (2). As the heating conditions, for example, a temperature higher than the curing temperature of the cationic electrodeposition coating composition by 0 to 15 ° C., that is, 130 ° C. to 235 ° C.
The obtained object to be coated is put into a dryer set at
Heating for 0 to 60 minutes can be mentioned. The electrodeposition coating film obtained in this manner has no pinholes and has high smoothness.

In the method for forming a coating film of the present invention, an intermediate coating material is applied on the electrodeposition coating film obtained in the above step (3), if necessary, in order to impart a base concealing property or chipping resistance. An intermediate coating film may be applied, and a top coating material may be applied to improve the design, the appearance, and the like, and the upper coating film may be applied. In this case, the intermediate coating and the top coating are
Painted by wet-on-wet painting method, 2
It is preferable to form a multilayer coating film by the coat 1 bake method from the viewpoint of shortening the process and saving energy. As the intermediate coating and the top coating, those well-known by those skilled in the art can be mentioned, and the coating conditions, the coating method, and the heating conditions can be appropriately set according to the type of the coating.

[0076]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. Note that “parts” means “parts by weight”.

Production Example 1 Acrylic Tree Having Epoxy Group
Fat Production 120 parts of butyl cellosolve was placed in a reaction vessel and heated and stirred at 120 ° C. A solution obtained by mixing 2 parts of t-butylperoxy-2-ethylhexanoate and 10 parts of butyl cellosolve was mixed with 40 parts of glycidyl methacrylate,
A monomer mixture consisting of 150 parts of ethylhexyl methacrylate, 50 parts of 2-hydroxyethyl methacrylate and 65 parts of n-butyl methacrylate having a solubility parameter of 10.1 was added dropwise over 3 hours. After aging for 30 minutes, a mixed solution of 0.5 part of t-butylperoxy-2-ethylhexanoate and 5 parts of butyl cellosolve was added dropwise over 30 minutes, and aging was further performed for 2 hours to obtain a nonvolatile matter of 42%. % Of an acrylic resin having an epoxy group content of 1%. Acrylic resin 1 having this epoxy group, determined by GPC in terms of polystyrene
Is GPC (gel permeation chromatography,
The number average molecular weight measured by polystyrene is 1100.
It was 0.

Production Example 2 Production of quaternizing agent 1 In a reaction vessel were placed 220 parts of isophorone diisocyanate, 40 parts of methyl isobutyl ketone, and 0.1 part of dibutyltin laurate.
22 parts were added, and 2-ethylhexanol 135 at 55 ° C was added.
Then, the mixture was reacted at 60 ° C. for 1 hour to obtain a half-blocked isocyanate solution. 80 more
It heated to ° C, and the solution which mixed 90 parts of N, N- dimethylaminoethanol and 10 parts of methyl isobutyl ketone was dripped over 30 minutes. After confirming the disappearance of the isocyanate group by IR, the mixture was cooled to room temperature to obtain a tertiary amine having a blocked isocyanate group. 50 more
The mixture is neutralized by adding 180 parts of a 1% aqueous lactic acid solution.
Was obtained.

Preparation Example 3 Preparation of quaternizing agent 2 Instead of 135 parts of 2-ethylhexanol used as a blocking agent in Preparation Example 2, 160 parts of triethylene glycol monomethyl ether was used, and the amount of methyl isobutyl ketone as a solvent was reduced. A solution of quaternizing agent 2 was obtained in the same manner except that the amount was changed from 40 parts to 25 parts.

Production Example 4 Acrylate Having Ammonium Group
Preparation of Resin 1 120 parts of butyl cellosolve were placed in a reaction vessel and heated and stirred at 120 ° C. A solution obtained by mixing 2 parts of t-butylperoxy-2-ethylhexanoate and 10 parts of butyl cellosolve, 15 parts of glycidyl methacrylate,
A monomer mixture consisting of 50 parts of -ethylhexyl methacrylate, 40 parts of 2-hydroxyethyl methacrylate and 15 parts of n-butyl methacrylate and having a solubility parameter of 10.1 was added dropwise over 3 hours. After aging for 30 minutes, a solution obtained by mixing 0.5 part of t-butyl peroxy-2-ethylhexanoate and 5 parts of butyl cellosolve was dropped in 30 minutes, and after aging for 2 hours, the mixture was cooled. . The acrylic resin 1 having an epoxy group had a number average molecular weight of 12,000 by GPC measurement,
The weight average molecular weight was 28,000. Where N, N-
Quaternization was performed by adding 7 parts of dimethylaminoethanol and 15 parts of a 50% lactic acid aqueous solution and heating and stirring at 80 ° C. When the acid value became 1 or less and the increase in viscosity stopped, heating was stopped to obtain an acrylic resin 1 solution having an ammonium group having a nonvolatile content of 30%. The number of ammonium groups per molecule of the acrylic resin 1 having this ammonium group was 6.0.

Production Example 5 Acrylate Having Ammonium Group
An acrylic resin having an epoxy group prepared in Preparation Example 1 of Le resin 2 1
In 240 parts of solution 1 of quaternizing agent 1 produced in Production Example 2.
Then, 00 parts were added and heated and stirred at 80 ° C. to perform quaternization.
Heating was stopped when the acid value became 1 or less and no increase in viscosity was observed, to obtain a solution of the acrylic resin 2 having an ammonium group having a nonvolatile content of 39%. The number of ammonium groups per molecule of the acrylic resin 2 having this ammonium group was 8.5.

Production Example 6 Acrylate Having Ammonium Group
In the same manner as in Production Example 5 of the resin 3 except that 80 parts of the solution of the quaternizing agent 2 produced in Production Example 3 was used instead of 100 parts of the solution of the quaternizing agent 1, % Of an acrylic resin 3 having an ammonium group. The number of ammonium groups per molecule of the acrylic resin 3 having this ammonium group was 4.0.

Production Example 7 Production of Crosslinked Resin Particles 1 20 parts of the ammonium group-containing acrylic resin 1 produced in Production Example 4 and 270 parts of deionized water were added to a reaction vessel and heated and stirred at 75 ° C. Here, 2,2′-azobis (2- (2-imidazolin-2-yl) propane) 1.
Five parts of a 100% neutralized acetic acid aqueous solution was added dropwise over 5 minutes.
After aging for 5 minutes, 30 parts of methyl methacrylate was added dropwise over 5 minutes. After further aging for 5 minutes, 170 parts of methyl methacrylate, 40 parts of styrene, 30 parts of n-butyl methacrylate, 5 parts of glycidyl methacrylate and 5 parts of a solution obtained by mixing 70 parts of the acrylic resin 1 having an ammonium group and 250 parts of deionized water were added. A pre-emulsion obtained by adding an α, β-ethylenically unsaturated monomer mixture consisting of 30 parts of neopentyl glycol dimethacrylate and stirring was added dropwise over 40 minutes.
After aging for 60 minutes, the mixture was cooled to obtain a dispersion of crosslinked resin particles 1. The dispersion of the obtained crosslinked resin particles 1 has a nonvolatile content of 35%, a pH of 5.0, and an average particle size of 100 nm.
Met.

Production Example 8 Production of Crosslinked Resin Particles 20 To a reaction vessel were added 20 parts of the ammonium group-containing acrylic resin 2 produced in Production Example 5 and 300 parts of deionized water, and the mixture was heated and stirred at 75 ° C. Here, 2,2′-azobis (2- (2-imidazolin-2-yl) propane)) 1
Was added dropwise over 5 minutes. 5
After aging for 25 minutes, 25 parts of methyl methacrylate was added dropwise over 5 minutes. After aging for another 5 minutes,
In a solution obtained by mixing 55 parts of the acrylic resin 2 having an ammonium group and 270 parts of deionized water, 140 parts of methyl methacrylate, 30 parts of styrene, 25 parts of n-butyl methacrylate, 5 parts of glycidyl methacrylate and 25 parts of neopentyl glycol dimethacrylate. Consisting of α,
A pre-emulsion obtained by adding a β-ethylenically unsaturated monomer mixture and stirring was dropped over 40 minutes. 60
After aging for a minute, the mixture was cooled to obtain a dispersion of the crosslinked resin particles 2. The dispersion of the obtained crosslinked resin particles 2 had a nonvolatile content of 30%, a pH of 5.5, and an average particle size of 100 nm.

Production Example 9 Production of Crosslinked Resin Particle Solution 3 The same procedure as in Production Example 8 was carried out except that the same amount of ammonium group-containing acrylic resin 3 was used instead of ammonium group-containing acrylic resin 2 used as an emulsifier. A dispersion of the resin particles 3 was obtained. The dispersion of the obtained crosslinked resin particles 3 had a nonvolatile content of 30%, a pH of 5.5, and an average particle size of 90 nm.

Production Example 10 Production of Crosslinked Resin Particle Solution 4 The same procedure as in Production Example 8 was carried out except that the amount of neopentyl glycol dimethacrylate in the α, β-ethylenically unsaturated monomer mixture was changed from 25 parts to 40 parts. According to the procedure, a dispersion of the crosslinked resin particles 4 was obtained. The dispersion of the obtained crosslinked resin particles 4 had a nonvolatile content of 30%, a pH of 5.0, and an average particle size of 150 nm.

Production Example 11 Production of Non-Crosslinked Resin Particles Into a reaction vessel, 20 parts of the acrylic resin 1 having an ammonium group produced in Production Example 4 and 300 parts of deionized water were added, and heated and stirred at 75 ° C. To this, a 100% neutralized acetic acid aqueous solution of 1 part of 2,2′-azobis (2- (2-imidazolin-2-yl) propane) was added dropwise over 5 minutes. After aging for 5 minutes, 10 parts of methyl methacrylate
Dropped over minutes. After further aging for 5 minutes, methyl methacrylate 140 was added to an aqueous solution of 55 parts of an acrylic resin having an ammonium group and 270 parts of deionized water.
, 30 parts of styrene, 25 parts of n-butyl methacrylate and 5 parts of glycidyl methacrylate, a poly (meth) acrylate-free α, β-ethylenically unsaturated monomer mixture was added, and the resulting pre-emulsion was stirred at 40 parts. Dropped over minutes. After aging for 60 minutes, the mixture was cooled to obtain a dispersion of non-crosslinked resin particles. The dispersion of the obtained non-crosslinked resin particles has a nonvolatile content of 32.8%,
pH was 5.0 and average particle diameter was 106 nm.

Production Example 12 Catalyst having an ammonium group
In a reaction vessel of the crosslinked resin particles using an emulsifier other than Lil resin, hexadecyltrimethylammonium chloride 7 parts was added as an emulsifier, which deionized water 30
The mixture was dissolved in 0 parts and heated and stirred at 75 ° C. Here 2,2 '
One part of azobis (2- (2-imidazolin-2-yl) propane) in 100% neutralized acetic acid was added dropwise over 5 minutes. After aging for 5 minutes, 10 parts of methyl methacrylate was added dropwise over 5 minutes. After further aging for 5 minutes, 140 parts of methyl methacrylate, 30 parts of styrene, 25 parts of n-butyl methacrylate, 25 parts of glycidyl methacrylate 5 were added to a solution obtained by mixing 22 parts of hexadecyltrimethylammonium chloride and 270 parts of deionized water.
Part and neopentyl glycol dimethacrylate 25
, A pre-emulsion obtained by stirring was added dropwise over 40 minutes. After aging for 60 minutes, the mixture was cooled to obtain a dispersion of crosslinked resin particles having a nonvolatile content of 30%.

Production Example 13 Sulfonium group and propane
Preparation of a resin composition having a lugyl group Epototo YDCN-701 having an epoxy equivalent of 200.4
(Cresol novolak type polyepoxy resin manufactured by Toto Kasei Co., Ltd.) Propargyl alcohol was added to 100.0 parts by weight.
6 parts by weight and 0.3 parts by weight of dimethylbenzylamine were added to a separable flask equipped with a stirrer, a thermometer, a nitrogen inlet tube and a reflux condenser, heated to 105 ° C. and reacted for 3 hours to give an epoxy equivalent of 1580. A resin composition containing a propargyl group was obtained. To this, 2.5 parts by weight of copper acetylacetonate was added and reacted at 90 ° C. for 1.5 hours. Proton (1H) NMR confirmed that part of the terminal hydrogen of the added propargyl group had disappeared (14 mmo).
1/100 g containing acetylated propargyl groups equivalent to resin solids). To this, 1- (2-hydroxyethylthio) -2,3-propanediol 10.6
Parts by weight, 4.7 parts by weight of glacial acetic acid, and 7.0 parts by weight of deionized water, and reacted for 6 hours while maintaining the temperature at 75 ° C. 0.8 part by weight was added to obtain a target resin composition solution. It has a solids concentration of 70.0% by weight and a sulfonium value of 28.
It was 0 mmol / 100 g varnish. The number average molecular weight (GPC in terms of polystyrene) was 2,443.

Examples 1 to 4 142.9 parts of the resin composition obtained in Preparation Example 13 and 157.1 parts of deionized water, and further, 7% with respect to the resin solid content in the paint. Each of the crosslinked resin particles 1 to 4 obtained in 7 to 10 was added, and 1
After stirring for an hour, 373.3 parts by weight of deionized water was further added, and an aqueous solution was prepared so that the solid content concentration became 15% by weight, to obtain a cationic electrodeposition paint. The curing temperature of the cationic electrodeposition coating composition was 150 ° C.

The obtained cationic electrodeposition coating material was transferred to a stainless steel container to form an electrodeposition bath. The object to be coated was treated with zinc phosphate, and then a 70 × 150 × 0.8 mm cold-rolled steel plate (JIS G). 3141 SPCC-SD, Nippon Paint Co., Ltd. zinc phosphate treating agent Surfdyne SD-500
0) as a cathode and the stainless steel container as an anode, and perform electrodeposition coating so as to have a dry film thickness of 30 μm. Dip for 30 seconds, wash with water, place on wire
Leave at 30 ° C. for 30 minutes. After standing, 0.2 g of deionized water and 0.2 g of mineral rust preventive oil were mixed, and the diameter was 1 cm and the height was 5 cm.
mm aluminum plate in the center of the electrodeposition coating
A test plate on which an electrodeposition coating film was formed was obtained by heating at 90 ° C. for 25 minutes.

Evaluation Test (1) Appearance of Coating Film The obtained coating film surface was visually observed and evaluated. In addition,
The evaluation criteria were as follows. ：: no repelling marks on the surface, very good △: slight repelling marks ×: repelling marks on the entire surface (2) Corrosion resistance Length about 10
cm scratches at 3 cm intervals on a test plate were 3% Na
After immersing in a Cl aqueous solution and leaving it closed at 55 ° C. for 10 days after sealing, the tape was adhered and peeled off, the peeling width of the coating film was measured, and the corrosion resistance was evaluated. The evaluation criteria were as follows. ：: Peeling width is 3 mm or less on one side △: Peeling width is more than 3 mm on one side and less than 5 mm ×: Peeling width is 5 mm or more on one side to the entire surface

Comparative Example 1 A cationic electrodeposition coating was obtained in the same manner as in Example 1 except that no crosslinked resin particles were added, and a test plate was obtained and evaluated.

Comparative Examples 2 to 3 Instead of the crosslinked resin particles obtained in Production Examples 7 to 10, emulsifiers other than the non-crosslinked resin particles obtained in Production Example 11 and the acrylic resin having an ammonium group obtained in Production Example 12 were used. A test plate was obtained and evaluated in the same manner as in Example 1 except that the used crosslinked resin particles were used.

[0095]

[Table 1]

As is clear from Table 1, the cationic electrodeposition paint containing a resin having a sulfonium group and a propargygyl group using the crosslinked resin particles of the present invention is a bumpy oil repellent subjected to heat curing after the electrodeposition coating. It was found that no appearance occurred and the appearance and corrosion resistance of the obtained coating film were good. However, it was found that when a cationic electrodeposition paint without using crosslinked resin particles or non-crosslinked resin particles was used, bumping oil repelling was generated, and not only the appearance of the coating film but also the anticorrosion property was reduced.

[0097]

Since the cationic electrodeposition coating composition of the present invention contains a resin composition having a sulfonium group and a propargyl group and crosslinked resin particles having a specific structure, it can be removed by degreasing or chemical conversion treatment. The generation of pinholes due to oils and fats adhering to the object to be coated, which could not be performed, can be suppressed without lowering the appearance of the coating film.

Further, the cationic electrodeposition coating composition of the present invention can suppress the occurrence of pinholes, so that the corrosion resistance of the coating film can be improved.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C09D 157/00 C09D 157/00 163/04 163/04 C25D 13/00 307 C25D 13/00 307A 307D 13 / 06 13/06 CF term (reference) 4J011 KA03 4J038 CA022 CB002 CC012 CE052 CF002 CG142 CG162 CG172 CH032 CH042 CH072 CH172 CJ132 DB021 DB061 DB071 DB091 DB201 DB211 DB221 DB331 DB351 DB391 GA01 GA03 GA08 GA07 KA04 PA19 P03

Claims (10)

[Claims] 1. A crosslinked resin particle obtained by emulsion-polymerizing an α, β-ethylenically unsaturated monomer mixture using a resin composition having a sulfonium group and a propargyl group and an acrylic resin having an ammonium group as an emulsifier. , Wherein the content of the crosslinked resin particles is 5 to 10% by weight based on the solid content of the coating resin. 2. The cationic electrode according to claim 1, wherein the ratio of the resin solid content of the ammonium group-containing acrylic resin to the α, β-ethylenically unsaturated monomer mixture is 90/10 to 75/25. Coating composition. 3. The α, β-ethylenically unsaturated monomer mixture contains 5 to 15% by weight of a poly (meth) acrylate having at least two α, β-ethylenically unsaturated bonds in a molecule.
The cationic electrodeposition coating composition according to claim 1, further comprising: 4. The cationic electrodeposition coating composition according to claim 1, wherein the number of ammonium groups in the ammonium resin having an ammonium group is 2 to 15 per molecule. 5. The acryl resin having an ammonium group is obtained by adding a tertiary amine compound and an organic acid to an acryl resin having an epoxy group to quaternize the resin. The cationic electrodeposition coating composition according to any one of the above. 6. The cationic electrodeposition coating composition according to claim 5, wherein the acrylic resin having an epoxy group has a number average molecular weight of 5,000 to 20,000. 7. The resin composition having a sulfonium group and a propargyl group has a sulfonium group content of 5 to 400 mm per 100 g of the resin solid content in the cationic electrodeposition coating composition.
The cationic electrodeposition coating composition according to any one of claims 1 to 6, comprising 10 to 495 mmol of ol and propargyl groups, and having a total content of sulfonium groups and propargyl groups of 500 mmol or less. 8. The resin composition having a sulfonium group and a propargyl group comprises a resin having a novolak phenol type epoxy resin or a novolak cresol type epoxy resin as a skeleton, and has a number average molecular weight of 7%.
And a sulfonium group of 5 to 250 m per 100 g of solid content of the resin composition.
The cationic electrodeposition coating composition according to any one of claims 1 to 7, wherein the cationic electrodeposition coating composition contains 20 to 395 mmol of a sulfonium group and a propargyl group, and a total content of the sulfonium group and the propargyl group is 400 mmol or less. 9. A step (1) of forming an electrodeposition film by electrodepositing the cationic electrodeposition coating composition according to any one of claims 1 to 8 on an object to be coated. (2) washing the electrodeposited film obtained by (1) with water;
A method for forming a coating film, comprising a step (3) of heating the washed electrodeposited film. 10. An object to be coated having a coating film obtained by the method for forming a coating film according to claim 9.