JP2005097607A - Aqueous resin composition and electrodeposition paint composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aqueous resin composition which can form a coating film that is excellent in flexibility and heat resistance without reducing its insulation properties and can be preferably used as a cation electrodeposition paint. <P>SOLUTION: This aqueous resin composition has a hydrating functional group and a polymerizable unsaturated carbon bonding. The base resin is at least a resin selected from a group consisting of polyamide-imide resins, polyamide resins and polyimide resins. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention relates to an aqueous resin composition and an electrodeposition coating composition.

In general, cationic electrodeposition coating having excellent corrosion resistance is performed as an undercoat of a metal material or the like. Furthermore, as a special application, cationic electrodeposition coating may be used to form an electrical insulating film on a metal material. As a cationic electrodeposition coating used for such cationic electrodeposition coating, an aqueous resin composition having a hydrated functional group and a polymerizable unsaturated carbon bond using an epoxy resin as a base resin is known (for example, Patent Documents). 1). In order to obtain a coating film having sufficient heat resistance using such a resin, it is necessary to form a cured coating film having a high crosslinking density. For this reason, the flexibility of the obtained coating film becomes insufficient, and the workability may be lowered.

On the other hand, an electrical insulating paint using a polyamideimide resin, a polyamide resin, a polyimide resin or the like is generally disclosed as a base resin (see, for example, Patent Documents 2 and 3). Since these base resins are excellent in heat resistance of the resin itself, a coating film having good heat resistance and excellent flexibility can be obtained without necessarily forming a cured film having a high crosslinking density. It has been known. However, these electrical insulating paints contain a large amount of volatile organic compounds (VOC), and have a problem from the viewpoint of environmental protection.

An electrodeposition coating composition is disclosed which is a water-based paint and has a polyimide resin having such a function as a base resin (see, for example, Patent Documents 4 and 5). However, such an electrodeposition coating composition cannot withstand long-term use due to insufficient stability. Moreover, the film thickness of the obtained coating film was not sufficient, and the electrical insulation was not satisfactory.
JP 2000-038525 A JP-A-5-295324 JP 2001-351441 A JP-A-9-124978 JP 2002-38078 A

The present invention provides an aqueous resin composition that can form a coating film excellent in flexibility and heat resistance without deteriorating insulation properties, and can be suitably used for cationic electrodeposition coatings. It is intended to do.

The present invention is an aqueous resin composition having a hydrated functional group and a polymerizable unsaturated carbon bond,
The base resin is an aqueous resin composition characterized in that it is at least one selected from the group consisting of a polyamideimide resin, a polyamide resin and a polyimide resin.
The hydrated functional group is preferably an onium group.
The onium group is preferably a sulfonium group.
The polymerizable unsaturated carbon bond is preferably derived from a propargyl group.
The aqueous resin composition preferably contains 5 to 100 mmol of sulfonium group and 10 to 150 mmol of propargyl group per 100 g of resin solid content, and the total content of the sulfonium group and propargyl group is preferably 200 mmol or less.
The present invention also provides an electrodeposition coating composition comprising the above aqueous resin composition.
Hereinafter, the present invention will be described in detail.

The aqueous resin composition of the present invention has a hydrated functional group and a polymerizable unsaturated carbon bond, and uses at least one selected from the group consisting of polyamideimide resin, polyamide resin and polyimide resin as a base resin. . By using at least one selected from the group consisting of the polyamideimide resin, polyamide resin and polyimide resin as a base resin, a coating film excellent in electrical insulation, heat resistance, workability and flexibility can be obtained. Is. Moreover, since it can process by water, it is safe and can reduce VOC.

The aqueous resin composition can be suitably used for electrodeposition coating. Since it can be applied by electrodeposition coating, it can be applied uniformly to the base material, and a film with little difference in film thickness can be formed on the base material even for a base material with a complicated shape. Can do.

The base resin of the aqueous resin composition of the present invention is at least one selected from the group consisting of a polyamideimide resin, a polyamide resin, and a polyimide resin. Since these resins are used as the base resin, the aqueous resin composition of the present invention can exhibit good heat resistance. The polyamide resin is not particularly limited. For example, it is obtained by mixing and polycondensing dicarboxylic acid and diamine compound or diisocyanate, or dehydrohalogenated by mixing halogenated dicarboxylic acid and diamine compound. The thing obtained by making it react can be mentioned. It does not specifically limit as said polyimide resin, For example, what is obtained by mixing and polycondensing tetracarboxylic dianhydride, a diamine compound, or diisocyanate etc. can be mentioned. It does not specifically limit as said polyamideimide resin, For example, what is obtained by mixing a tricarboxylic acid anhydride, a diamine compound, or diisocyanate and carrying out polycondensation etc. can be mentioned.

Specific examples of the dicarboxylic acid include aliphatic dicarboxylic acids such as adipic acid, azelaic acid, and sebacic acid and their derivatives; terephthalic acid, isophthalic acid, 2-chloroterephthalic acid, terephthalic acid dichloride, and 2-methylterephthalic acid. And aromatic or alicyclic dicarboxylic acids such as 5-methylisophthalic acid, hexahydroterephthalic acid and hexahydroisophthalic acid, and derivatives thereof.

Specific examples of the tetracarboxylic dianhydride include pyromellitic dianhydride, 3,4,3 ′, 4′-benzophenonetetracarboxylic dianhydride, 3,4,3 ′, 4′-. Examples include diphenylsulfonetetracarboxylic dianhydride, bis- (3,4-dicarboxyphenyl) ether anhydride, 2,2-bis- (3,4-dicarboxyphenyl) hexafluoropropane dianhydride, and the like. it can.

Specific examples of the tricarboxylic acid anhydride include butanetricarboxylic acid anhydride, trimellitic acid anhydride, benzophenone tricarboxylic acid anhydride, diphenylsulfone tricarboxylic acid anhydride, diphenyl ether tricarboxylic acid anhydride, diphenyltricarboxylic acid anhydride, Examples thereof include tricarboxylic acid anhydrides such as diphenylpropane tricarboxylic acid anhydride and diphenylhexafluoropropane tricarboxylic acid anhydride, and derivatives thereof.

Specific examples of the diamine compound include aliphatic diamine compounds such as hexamethylenediamine, tetramethylenediamine, and 4,4′-diaminocyclohexane; p-phenylenediamine, m-phenylenediamine, and 4,4′-diamino. Examples include aromatic diamine compounds such as diphenylmethane, 4,4′-diaminodiphenyl ether, and 2,4-dimethylmetaphenylenediamine.

Specific examples of the diisocyanate include aliphatics such as hexamethylene diisocyanate (HMDI), isophorone diisonate (IPDI), 4,4′-methylenebis (cyclohexyl isocyanate) (hydrogenated MDI), norbornane diisocyanate (NBDI), and the like. Diisocyanates; aromatic diisocyanates such as tolylene diisocyanate (TDI), 4,4′-diphenylmethane diisocyanate (MDI), xylylene diisocyanate (XDI) can be mentioned. Moreover, these alcohol block types can be used.
The base resin of the aqueous resin composition of the present invention is preferably a polyamide-imide resin because of its heat resistance and ease of synthesis.

The aqueous resin composition has a hydrated functional group and a polymerizable unsaturated carbon bond. The base resin constituting the aqueous resin composition may have both a hydrated functional group and a polymerizable unsaturated carbon bond in one molecule, but it is not always necessary, for example, in one molecule. You may have only one of a hydration functional group or a polymerizable unsaturated carbon bond. In the latter case, the entire resin composition has these two types. That is, the aqueous resin composition is composed of a resin having a hydrated functional group and a polymerizable unsaturated carbon bond, or a mixture of a resin having only a hydrated functional group and a resin having only a polymerizable unsaturated carbon bond. Or a mixture of all of these. The said aqueous resin composition has a hydration functional group and a polymerizable unsaturated carbon bond in the above-mentioned meaning.

The hydrated functional group is not particularly limited, and examples thereof include onium groups such as an ammonium group, a sulfonium group, and a phosphonium group. Among these, an ammonium group and a sulfonium group are preferable because of high adhesion to a metal substrate, and a sulfonium group is more preferable.

Furthermore, the aqueous resin composition of the present invention has a polymerizable unsaturated carbon bond. That is, a coating film is formed by a curing reaction by polymerization of a polymerizable unsaturated carbon bond. Since the curing of the film proceeds by such a curing reaction, it is possible to suppress the generation amount of volatile components at the time of curing, and it is possible to prevent a decrease in electrical insulation due to voids caused by the volatile components in the film. .

The polymerizable unsaturated carbon bond is not particularly limited as long as the unsaturated bond is polymerized to form a curing system in which the reaction proceeds. For example, propargyl / allene curing system, α, β of active methylene group -Polymerizable unsaturated carbon bonds that form curing systems such as Michael addition curing systems and oxidation polymerization curing systems to unsaturated bonds. Among these, a polymerizable unsaturated carbon bond that forms a propargyl / allene curing system is preferable because the curing reaction is promoted when used in combination with the onium group. That is, the aqueous resin composition of the present invention preferably has a propargyl group.

The aqueous resin composition of the present invention preferably has a sulfonium group and a propargyl group. When the aqueous resin composition having the sulfonium group and the propargyl group is used as a cationic electrodeposition coating, when a voltage or current of a certain level or higher is applied in the electrodeposition step, the sulfonium group undergoes an electrolytic reduction reaction on the electrode. The ionic group disappears, becomes irreversibly nonconductive, and can be deposited as a coating. Moreover, in this electrodeposition process, it is considered that an electrode reaction is caused, and the generated hydroxide ions are retained by the sulfonium group, whereby an electrogenerated base is generated in the coating. This electrogenerated base can convert a propargyl group that is less reactive by heating present in the coating to an allene bond that is more reactive by heating. That is, polymerization derived from an allene bond proceeds during heat curing after the electrodeposition step, and the curing reaction is promoted. Thus, by having these two functional groups, it is possible to obtain a coating film having excellent adhesion to the substrate.

When the aqueous resin composition has a sulfonium group and a propargyl group, the content of the sulfonium group in the aqueous resin composition is within a range of a lower limit of 5 mmol and an upper limit of 100 mmol per 100 g of the solid content of the resin composition. It is preferable that When the content is less than 5 mmol / 100 g, sufficient curability cannot be exhibited, and hydration property and bath stability are deteriorated. When the content exceeds 100 mmol / 100 g, deposition of a coating on the surface of the substrate is deteriorated. The content of the sulfonium group can be set more preferably depending on the resin skeleton used.

When the aqueous resin composition has a sulfonium group and a propargyl group, the content of the propargyl group in the aqueous resin composition is a lower limit of 10 mmol and an upper limit of 150 mmol per 100 g of the solid content of the resin composition. Is preferred. If the content is less than 10 mmol / 100 g, sufficient curability cannot be exhibited, and if it exceeds 150 mmol / 100 g, the flexibility of the resulting coating film may be reduced. In addition, content of the said propargyl group can set more preferable content according to the resin frame | skeleton used.

When the aqueous resin composition has a sulfonium group and a propargyl group, the total content of the sulfonium group and the propargyl group of the aqueous resin composition is 200 mmol or less per 100 g of the solid content of the resin composition. Is preferred. If it exceeds 200 mmol / 100 g, the resin may not actually be obtained or the intended performance may not be obtained. The total content of the sulfonium group and propargyl group can be set to a more preferable content depending on the resin skeleton used.

A part of the propargyl group in the aqueous resin composition may be acetylated. Acetylide is a salt-like metal acetylenide. The content of propargyl group to be acetylated in the aqueous resin composition is preferably a lower limit of 0.1 mmol and an upper limit of 40 mmol per 100 g of the solid content of the resin composition. If it is less than 0.1 mmol, the effect of acetylide formation is not sufficiently exhibited, and if it exceeds 40 mmol, acetylide formation is difficult. It is possible to set a more preferable range for this content depending on the metal used.

The metal contained in the acetylated 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 these, considering environmental compatibility, copper and silver are preferable, and copper is more preferable from the viewpoint of availability. When copper is used, the content of propargyl group to be acetylated in the aqueous resin composition is more preferably 0.1 to 20 mmol per 100 g of the solid content of the resin composition.

A curing catalyst can be introduced into the resin composition by acetylating a part of the propargyl group in the aqueous resin composition. In this way, it is generally unnecessary to use an organic transition metal complex that is difficult to dissolve or disperse in an organic solvent or water, and even a transition metal can be easily acetylated and introduced. Even metal compounds can be freely used in coating compositions. Further, as in the case of using a transition metal organic acid salt, it can be avoided that the organic acid salt is present as an anion in the electrodeposition bath, and further, the metal ion is not removed by ultrafiltration. Management and coating composition design are facilitated.

The aqueous resin composition of the present invention preferably has a mass average molecular weight in the range of a lower limit of 1000 and an upper limit of 5000. When it is less than 1000, heat resistance and flexibility are lowered, and when it exceeds 5000, a good film cannot be formed on the surface of the metal substrate. The mass average molecular weight can be set to a more preferable molecular weight depending on the resin skeleton.

If desired, the aqueous resin composition may contain a carbon-carbon double bond. Since the carbon-carbon double bond has high reactivity, the curability can be further improved.

The method for introducing the sulfonium group and propargyl group is not particularly limited. For example, a step of obtaining an epoxy compound having a propargyl group by reacting an epoxy compound with a functional group that reacts with an epoxy group and a compound having a propargyl group ( i) a step of introducing a propargyl group and a sulfonium group by reacting a polyamide resin, a polyimide resin or a polyamideimide resin, an epoxy compound having a propargyl group obtained in step (i), and a sulfide / acid mixture ( The method (I) which consists of ii) can be mentioned.

Examples of the compound having a functional group that reacts with the epoxy group and a propargyl group (hereinafter referred to as “compound (A)”) include, for example, a functional group that reacts with an epoxy group such as a hydroxyl group or a carboxyl group and a propargyl group. It may be a compound to be contained, and specific examples include propargyl alcohol and propargylic acid. Of these, propargyl alcohol is preferred because of its availability and ease of reaction.

When the resin composition has a carbon-carbon double bond, if necessary, in the step (i), a compound having a functional group that reacts with an epoxy group and a carbon-carbon double bond (hereinafter referred to as “carbon-carbon double bond”). , "Compound (B)") may be used in combination with the compound (A). The compound (B) may be, for example, a compound containing both a functional group that reacts with an epoxy group such as a hydroxyl group or a carboxyl group and a carbon-carbon double bond.

In the step (i), the epoxy compound is reacted with the compound (A) to obtain an epoxy compound having a propargyl group, or the compound (A) and, if necessary, the compound (B). To obtain an epoxy compound having a propargyl group and a carbon-carbon double bond. In this latter case, in the step (i), the compound (A) and the compound (B) may be used in the reaction after they are mixed in advance, or the compound (A) and the compound may be used. (B) may be used separately in the reaction. The functional group that reacts with the epoxy group of the compound (A) and the functional group that reacts with the epoxy group of the compound (B) may be the same or different.

The reaction conditions in the above step (i) are usually several hours at room temperature or 80 to 140 ° C. Moreover, the well-known component required in order to advance reaction, such as a catalyst and a solvent, can be used as needed. The completion of the reaction can be confirmed by measuring the epoxy equivalent, and the introduced functional group can be confirmed by measuring the nonvolatile content of the obtained resin composition or analyzing the instrument. The reaction product thus obtained is generally a mixture of epoxy compounds having one or more propargyl groups or an epoxy compound having one or more propargyl groups and carbon-carbon double bonds. It is a mixture of In this sense, an epoxy compound having a propargyl group is obtained by the step (i).

In the step (ii), a polyamideimide resin, a polyamide resin or a polyimide resin, an epoxy compound having a propargyl group obtained in the above step (i), and a sulfide / acid mixture are reacted to form a sulfonium group on the epoxy group. In addition, an epoxy compound having a propargyl group and a sulfonium group is reacted with a polyamideimide resin, a polyamide resin, or a polyimide resin. The introduction of the sulfonium group may be carried out by reacting a sulfide / acid mixture with an epoxy group to introduce the sulfide and sulfonium, or after introducing the sulfide, the acid or methyl fluoride, methyl chloride, methyl bromide, etc. It can be carried out by a method of performing a sulfoniumation reaction of the introduced sulfide with an alkyl halide or the like and, if necessary, anion exchange. From the viewpoint of easy availability of reaction raw materials, a method using a sulfide / acid mixture is preferred.

The sulfide is not particularly limited, and examples thereof include aliphatic sulfide, aliphatic monoaromatic mixed sulfide, aralkyl sulfide, and cyclic sulfide. Specifically, for example, diethyl sulfide, dipropyl sulfide, dibutyl sulfide, dihexyl sulfide, diphenyl sulfide, ethylphenyl sulfide, tetramethylene sulfide, pentamethylene sulfide, thiodiethanol, thiodipropanol, thiodibutanol, 1- (2 -Hydroxyethylthio) -2-propanol, 1- (2-hydroxyethylthio) -2-butanol, 1- (2-hydroxyethylthio) -3-butoxy-1-propanol and the like can be mentioned.

The acid is not particularly limited, and for example, 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, etc. Can be mentioned.

In general, the mixing ratio of the sulfide and the acid in the sulfide / acid mixture is preferably about sulfide / acid = 100/40 to 100/100 in terms of molar ratio.

The reaction in the step (ii) includes, for example, an epoxy compound having a propargyl group obtained in the step (i), a predetermined amount of the sulfide set to have the sulfonium group content, and the above The mixture with the acid can be mixed with 5 to 10 moles of water of the sulfide used and usually stirred at 50 to 90 ° C. for several hours. The end point of the reaction may be a measure that the residual acid value is 5 or less. Confirmation of sulfonium group introduction in the obtained aqueous resin composition can be performed by potentiometric titration.

Even when the sulfoniumation reaction is carried out after the introduction of the sulfide, it can be carried out according to the above. As described above, by introducing the sulfonium group after the introduction of the propargyl group, decomposition of the sulfonium group due to heating can be prevented.
As a method for introducing the sulfonium group and propargyl group, in addition to the above method (I), an epoxy group and / or propargyl group may be used as a raw material monomer when producing a polyamide resin, polyimide resin or polyamideimide resin as a base resin. There can be mentioned the method (II) in which a sulfonium group is introduced by reacting with a sulfide / acid mixture after polymerization using a compound to which is added. Further, when the base resin is a polyamide resin, after the polyamide resin is produced, the compound having a functional group that reacts with the functional group at the end of the polyamide and a compound having a propargyl group are reacted, and then reacted with a sulfide / acid mixture, The method (III) etc. which introduce | transduce a propargyl group and a sulfonium group can be mentioned.

The monomer to which the epoxy group and / or propargyl group is added is not particularly limited, and for example, those obtained by adding propargyl alcohol to pyromellitic acid anhydride or trimellitic acid anhydride can be used.
In addition, the compound having a functional group that reacts with the functional group at the end of the polyamide and a propargyl group is not particularly limited. can do.

When acetylating a part of the propargyl group of the resin composition, when using the method (I), the epoxy compound having the propargyl group obtained in the step (i) is reacted with a metal compound, It can be carried out by a step of converting some propargyl groups in the epoxy compound into acetylides. The metal compound is preferably a transition metal compound capable of acetylation, and examples thereof include the above-mentioned transition metal complexes or salts. Specific examples include acetylacetone copper, copper acetate, acetylacetone silver, silver acetate, silver nitrate, acetylacetone barium, and barium acetate. Among these, from the viewpoint of environmental compatibility, a copper or silver compound is preferable, and from the viewpoint of availability, a copper compound is more preferable. For example, acetylacetone copper is preferable in view of ease of bath management. .

In addition, when using the method (I), the reaction conditions for the step of acetylating a part of the propargyl group of the epoxy compound and the step (ii) can be set in common, so both steps are performed simultaneously. Is also possible. The method of performing both steps simultaneously is advantageous because the manufacturing process can be simplified.

In this way, a resin composition having a propargyl group and a sulfonium group, and if necessary, a carbon-carbon double bond and a part of the propargyl group acetylated is produced while suppressing the decomposition of the sulfonium group. can do. Although acetylide has explosive properties in a dry state, it is carried out in an aqueous medium and the target substance can be obtained as an aqueous composition, so that no safety problem occurs.

The aqueous resin composition of the present invention is obtained by dispersing the resin composition obtained as described above in an aqueous medium. It does not specifically limit as said aqueous medium, For example, the mixed solvent of water and water and another solvent can be mentioned. The other solvent is not particularly limited as long as it is compatible with water, and examples thereof include hydrocarbons (for example, xylene or toluene), alcohols (for example, methyl alcohol, n-butyl alcohol, isopropyl alcohol). 2-ethylhexyl alcohol, ethylene glycol, propylene glycol), ethers (for example, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, propylene glycol monoethyl ether, 3-methyl-3-methoxybutanol, Diethylene glycol monoethyl ether, diethylene glycol monobutyl ether), ketones (eg, methyl isobutyl ketone, cyclohexanone, isophorone, acetylacetone) Esters (e.g., ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate), and can include mixtures thereof, and the like.

The present invention is also an electrodeposition coating composition comprising the above aqueous resin composition. The above-mentioned electrodeposition coating composition contains the above-mentioned aqueous resin composition and is applied by electrodeposition coating. Therefore, the electrodeposition coating composition is uniform, heat resistance, and workability even for an object having a complicated shape. A film having excellent flexibility can be obtained.

The electrodeposition coating composition does not necessarily require the use of a curing agent because the resin composition itself has curability. However, it may be used for further improving the curability. Examples of such a curing agent include a compound having a plurality of at least one of a propargyl group and a carbon-carbon double bond, for example, polyepoxide such as novolac phenol, pentaerythritol tetraglycidyl ether, propargyl alcohol, etc. And compounds obtained by addition reaction of a compound having a propargyl group or a compound having a carbon-carbon double bond such as acrylic acid.

In the electrodeposition coating composition, it is not always necessary to use a curing catalyst. However, when it is necessary to further improve the curability depending on the curing reaction conditions, a transition metal compound or the like that is usually used may be added as necessary. Such a compound is not particularly limited. For example, a compound in which a transition metal such as nickel, cobalt, manganese, palladium, or rhodium is bonded with a ligand such as cyclopentadiene or acetylacetone or a carboxylic acid such as acetic acid. Etc. The blending amount of the curing catalyst is preferably a lower limit of 0.1 and an upper limit of 20 mmol per 100 g of resin solid content in the electrodeposition coating composition.

An amine can be blended in the electrodeposition coating composition of the present invention. By blending the amine, the conversion rate of sulfonium groups to sulfides by electrolytic reduction in the electrodeposition process is increased. The amine is not particularly limited, and examples thereof include amine compounds such as primary to tertiary monofunctional and polyfunctional aliphatic amines, alicyclic amines, and aromatic amines. Among these, water-soluble or water-dispersible ones are preferable, for example, monoalkylamine, dimethylamine, trimethylamine, triethylamine, propylamine, diisopropylamine, tributylamine and other alkylamines having 2 to 8 carbon atoms; monoethanolamine, Examples include dimethanolamine, methylethanolamine, dimethylethanolamine, cyclohexylamine, morpholine, N-methylmorpholine, pyridine, pyrazine, piperidine, imidazoline, and imidazole. These may be used alone or in combination of two or more. Of these, hydroxyamines such as monoethanolamine, diethanolamine, and dimethylethanolamine are preferred because of excellent water dispersion stability.

The amine can be directly blended in the electrodeposition coating composition of the present invention. In the conventional neutralized amine-based cationic electrodeposition coating, when a free amine is added, the neutralized acid in the resin is deprived, and the stability of the electrodeposition solution is remarkably deteriorated. There is no such inhibition of bath stability.

The compounding amount of the amine is preferably 0.3 to 100 meq per 100 g of resin solid content in the electrodeposition coating composition. If it is less than 0.3 meq / 100 g, a sufficient effect on throwing power cannot be obtained, and if it exceeds 100 meq / 100 g, an effect according to the amount added cannot be obtained, which is uneconomical. More preferably, it is 1-15 meq / 100g.

The electrodeposition coating composition of the present invention can also be blended with a resin composition having an aliphatic hydrocarbon group. By blending the resin composition having an aliphatic hydrocarbon group, the impact resistance of the resulting coating film is improved. As the resin composition having an aliphatic hydrocarbon group, the chain may contain an unsaturated double bond having 5 to 400 mmol of sulfonium group and 8 to 24 carbon atoms per 100 g of the solid content of the resin composition. It contains at least one kind of hydrocarbon group 80 to 135 mmol and an organic group and propargyl group having an unsaturated double bond having 3 to 7 carbon atoms, and a sulfonium group having 8 to 24 carbon atoms. The total content of the aliphatic hydrocarbon group which may contain an unsaturated double bond in the chain, the organic group having an unsaturated double bond having 3 to 7 carbon atoms and the propargyl group is solid in the resin composition The thing which is 500 mmol or less per 100 g of minutes can be mentioned.

When blending a resin composition having an aliphatic hydrocarbon group with respect to the electrodeposition coating composition, 5 to 400 mmol of sulfonium groups and 8 to 24 carbon atoms per 100 g of resin solid content in the electrodeposition coating composition. A total of 10 to 485 mmol of an aliphatic hydrocarbon group which may contain an unsaturated double bond in the chain, and a propargyl group and an organic group having an unsaturated double bond having 3 to 7 carbon atoms at the end. Containing a sulfonium group, an aliphatic hydrocarbon group which may contain an unsaturated double bond having 8 to 24 carbon atoms in the chain, and a propargyl group and an unsaturated double bond having 3 to 7 carbon atoms The total content of organic groups in the resin is 500 mmol or less per 100 g of the solid content of the electrodeposition coating resin, and the aliphatic hydrocarbon group which may contain the unsaturated double bond having 8 to 24 carbon atoms in the chain. Content is preferably 3 to 30% by weight of the resin solids of the electrodeposition coating composition.

When the resin composition having an aliphatic hydrocarbon group is blended with the electrodeposition coating composition, if the sulfonium group is less than 5 mmol / 100 g, sufficient throwing power and curability cannot be exhibited. In addition, the hydration property and bath stability deteriorate. When it exceeds 400 mmol / 100 g, the deposition of the coating on the surface of the object to be coated becomes worse. When the aliphatic hydrocarbon group having 8 to 24 carbon atoms and optionally containing an unsaturated double bond in the chain is less than 80 mmol / 100 g, the impact resistance is not improved sufficiently, and 350 mmol / When it exceeds 100 g, the handleability of the resin composition becomes difficult. When the total of the propargyl group and the organic group having an unsaturated double bond having 3 to 7 carbon atoms is less than 10 mmol / 100 g, it is sufficient even when used in combination with other resins and curing agents. If the curability cannot be exhibited and the amount exceeds 315 mmol / 100 g, the improvement in impact resistance becomes insufficient. A sulfonium group, an aliphatic hydrocarbon group which may contain an unsaturated double bond having 8 to 24 carbon atoms in the chain, and a propargyl group and an organic group having an unsaturated double bond having 3 to 7 carbon atoms at its end. The total content is 500 mmol or less per 100 g of the resin composition solid content. If it exceeds 500 mmol, the resin may not actually be obtained or the intended performance may not be obtained.

Furthermore, the said electrodeposition coating material composition may contain the other component used for a normal electrodeposition coating material as needed. The other components are not particularly limited, and examples thereof include pigments, rust inhibitors, pigment dispersion resins, surfactants, antioxidants, and ultraviolet absorbers.

The pigment is not particularly limited, and examples thereof include coloring pigments such as titanium dioxide, carbon black, and bengara; antirust pigments such as basic lead silicate and aluminum phosphomolybdate; extender pigments such as kaolin, clay, and talc. Can be mentioned. Specific examples of the rust inhibitor include calcium phosphite, zinc calcium phosphite, calcium-supporting silica, and calcium-supporting zeolite. The total blending amount of the pigment and the rust inhibitor is preferably a lower limit of 0% by mass and an upper limit of 50% by mass as the solid content in the electrodeposition coating composition.

The pigment dispersion resin is used to stably disperse the pigment in the electrodeposition coating composition. The pigment dispersion resin is not particularly limited, and a commonly used pigment dispersion resin can be used.

When performing electrodeposition coating using the electrodeposition coating composition of the present invention, the material to be coated is not particularly limited as long as it has conductivity, such as an iron plate, a steel plate, an aluminum plate, and a surface treatment thereof. And those molded products.

Examples of the electrodeposition coating include cationic electrodeposition coating which is usually performed by applying a voltage of 50 to 450 V between an object to be coated as a cathode and an anode. If the applied voltage is less than 50V, electrodeposition is insufficient, and if it exceeds 450V, the power consumption increases, which is uneconomical. When a voltage is applied within the above-described range using the electrodeposition coating composition of the present invention, a uniform film can be formed on the entire object to be coated without causing a sudden increase in film thickness during the electrodeposition process. it can.
The bath temperature of the electrodeposition coating composition when applying the voltage is usually preferably 10 to 60 ° C.

The electrodeposition process includes (1) a process of immersing an object to be coated in an electrodeposition coating composition, and (2) a process in which a voltage is applied between the object to be coated as a cathode and an anode is deposited, It is preferable that it is comprised. Moreover, although the time which applies a voltage changes with electrodeposition conditions, generally it can be made into 2 to 4 minutes.

The electrodeposition film obtained as described above can be cured by baking at 150 to 260 ° C. for 10 to 30 minutes after completion of the electrodeposition process, or after being washed with water to obtain a cured film.
The thickness of the electrodeposition coating film after curing is preferably in the range of a lower limit of 5 μm and an upper limit of 200 μm. If it is out of the above range, the resulting coating film may be non-uniform.
The coating object on which the coating film obtained in this way is formed may be further subjected to intermediate coating and / or top coating depending on the purpose.

The aqueous resin composition of the present invention is an electrodeposition coating that has at least one selected from the group consisting of polyamideimide resin, polyamide resin, and polyimide resin excellent in heat resistance and flexibility as a base resin, and has excellent coating workability It can be applied more suitably. Moreover, since the said aqueous resin composition has a hydration functional group and a polymerizable unsaturated carbon bond, it can obtain the coating film excellent in adhesiveness. Furthermore, since the base resin of the resin composition is at least one selected from the group consisting of a polyamideimide resin, a polyamide resin, and a polyimide resin, the resulting coating film is excellent in insulation.

Examples The present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples. In the examples, “parts” means “parts by mass” unless otherwise specified.

Example 1
To 431 parts by mass of Epototo YH-300 (epoxy compound manufactured by Tohto Kasei Co., Ltd.) having an epoxy equivalent of 144, 180 parts by mass of propargyl alcohol was added to a separable flask equipped with a stirrer, thermometer, nitrogen inlet tube and reflux condenser. The reaction mixture was allowed to react for 5 hours to obtain an epoxy compound containing a propargyl group.
A separable flask equipped with 321 parts by mass of N-methyl-2-pyrrolidone, 192 parts by mass of trimellitic anhydride and 200 parts by mass of diphenylmethane-4,4′-diisocyanate, equipped with a stirrer, thermometer, nitrogen inlet tube and reflux condenser In addition, the temperature was raised to 150 ° C. and reacted for 10 hours to obtain a resin composition.
This was cooled to 80 ° C., 243 parts by mass of the epoxy compound containing the propargyl group obtained above was added, reacted for 5 hours, and further 54 parts by mass of 1- (2-hydroxyethylthio) propan-2-ol. Then, 19 parts by mass of glacial acetic acid and 57 parts by mass of deionized water were added and reacted for 6 hours while keeping at 75 ° C. After confirming that the acid value was 5 or less, 2273 parts by mass of deionized water was added, An aqueous resin composition was obtained. The solid content of this product was 20% by mass, and the sulfonium group was 28 mmol / 100 g varnish.

Comparative Example 1
Epototo YDCN-703 (epoxy compound manufactured by Tohto Kasei Co., Ltd.) having an epoxy equivalent of 203 was added to 234 parts by mass of propargyl alcohol (101 parts by mass) in a separable flask equipped with a stirrer, thermometer, nitrogen inlet tube and reflux condenser. The reaction mixture was allowed to react for 5 hours to obtain an epoxy compound containing a propargyl group.
This was cooled to 80 ° C., and 27 parts by mass of 1- (2-hydroxyethylthio) propan-2-ol, 29 parts by mass of glacial acetic acid and 10 parts by mass of deionized water were added and reacted for 6 hours while keeping at 75 ° C. After confirming that the acid value was 5 or less, 1222 parts by mass of deionized water was added to obtain the desired aqueous resin composition. The solid concentration of this product was 20% by mass, and the sulfonium group was 28 mmol / 100 g varnish.

The aqueous resin compositions obtained in Evaluation Test Example 1 and Comparative Example 1 were placed in a stainless 4L container to form an electrodeposition bath. Electrodeposition coating was performed on a copper plate having a thickness of 0.3 mm and a size of 35 × 75 mm in the bath so that the dry film thickness was 100 μm. The obtained copper plate was washed with water and then heat-cured at 250 ° C. for 20 minutes to obtain an electrodeposition coating film. The obtained electrodeposition coating film was evaluated as follows, and the results are shown in Table 1.
(1) Flexibility test Using a steel rod having a diameter of 5 mm as the center of bending, it was bent 180 ° at 25 ° C. for 0.5 seconds, and the presence or absence of cracks in the electrodeposition coating was investigated.
(2) Heat resistance test Heated at 250 ° C for 24 hours, the mass residual ratio before and after heating was calculated.
(3) A measurement terminal of a withstand voltage insulation tester MODEL8525 (manufactured by Tsuruga Electric Co., Ltd.) is connected to a part of the conductive copper plate that conducts and a part of the obtained electrodeposition coating film, and the measurement condition is 500 V / sec. The breakdown voltage was measured.

From Table 1, it was shown that the coating film obtained by the aqueous resin composition of the present invention is excellent in flexibility, heat resistance and insulation.

A coating film excellent in heat resistance and flexibility can be obtained by the aqueous resin composition of the present invention. As a result, the workability is also improved, and it can be applied to the electric and electronic fields. Moreover, since the aqueous resin composition of this invention is used suitably for electrodeposition coating, it can coat efficiently also to the to-be-coated object which has a complicated shape.

Claims (6)

An aqueous resin composition having a hydrated functional group and a polymerizable unsaturated carbon bond,
The aqueous resin composition, wherein the base resin is at least one selected from the group consisting of a polyamideimide resin, a polyamide resin, and a polyimide resin. The aqueous resin composition according to claim 1, wherein the hydrated functional group is an onium group. The aqueous resin composition according to claim 2, wherein the onium group is a sulfonium group. The water-based resin composition according to claim 1, 2 or 3, wherein the polymerizable unsaturated carbon bond is derived from a propargyl group. 5. The aqueous resin composition according to claim 4, comprising 5 to 100 mmol of sulfonium group and 10 to 150 mmol of propargyl group per 100 g of resin solid content, and the total content of the sulfonium group and propargyl group is 200 mmol or less. An electrodeposition coating composition comprising the aqueous resin composition according to claim 1, 2, 3, 4 or 5.