JP2000038524A - Cationic electrodeposition coating composition free of exogenous endocrine interrupter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a highly environmentally friendly coating composition excellent in throwing power and workability by using a material instead of bisphenol A or an alkylphenol being an exogenous endocrine interrupter, the so-called environmental hormone. SOLUTION: There is provide a cationic electrodeposition coating composition, wherein the base resin is a novolac epoxy resin being a substitute for a bisphenol A epoxy resin, and the surface modifier is a long-chain hydrocarbon group being a substitute for an alkylphenol. This composition contains base resins A and B each having a novolac epoxy resin as the skeleton. The novolac epoxy resin is desirably a novolac phenol epoxy resin or a novolac cresol epoxy resin. The 8-24C aliphatic hydrocarbon group which is contained in resin B and may contain a double bond in the chain functions as a soft segment in an electro-deposited coating film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates to a highly environmentally friendly cationic electrodeposition coating composition, and more particularly, to a cationic electrocoating composition which can be produced without using endogenous endocrine disrupting chemicals. The present invention relates to a cationic electrodeposition coating composition that is substantially free of various chemical substances.

[0002]

2. Description of the Related Art Cathodic electrodeposition coating is capable of applying a coating to a small part even if the object has a complicated shape.
Since it can be coated automatically and continuously, it is widely used as an undercoating method for an object to be coated which has a large and complicated shape such as an automobile body and requires high rust prevention. Further, the use efficiency of the paint is extremely high as compared with other coating methods, so that it is economical and widely used as an industrial coating method.

In most cases, the cationic electrodeposition coating composition used for the cationic electrodeposition coating uses an epoxy resin as a base resin, and moreover, the epoxy resin conventionally used in the cationic electrodeposition coating composition is used. Almost as a resin,
A bisphenol A type epoxy resin obtained by a reaction between bisphenol A and epichlorohydrin has been used. This is because this resin has excellent properties such as anticorrosion property and adhesion. In addition, it is easy to design a curing system using block isocyanate as a curing agent,
Further, it is easy to obtain due to advantages in production on an industrial scale.

[0004] Usually, an alkylphenol is used as a surface conditioner, and nonylphenol, 4-octylphenol or the like is used as a raw material or is accompanied as a decomposition product.

However, in recent years, it has been found that substances such as bisphenol A, nonylphenol, and 4-octylphenol have a very small effect on animals. It has been pointed out that these substances, when taken into the body of an animal, may affect the normal hormonal action that is naturally performed in the living body and become exogenous endocrine disrupting chemicals. One of the new and important issues above.

In particular, it is known that bisphenol A, nonylphenol and the like exert a similar effect to estrogen by binding to estrogen receptors. It has also been pointed out that if these chemicals constantly give estrogen-like effects to genes, they may cause cancer or fetal malformation during pregnancy. Therefore, the effects of the release of such chemicals into the environment can be extended over generations and over time, and the need to prevent such dangers is recognized worldwide. It has become.

[0007] For example, at the Eighth Environment Ministers' Meeting held in Miami, USA in May 1997, endocrine disrupting chemicals were recognized as an imminent threat to the health of children, and endocrine disrupting chemicals were identified. Has been declared to promote risk management and prevention strategies for major sources of Also, in May 1998, the Environment Agency of Japan stated that it has an endocrine disrupting effect in Table 3 of "Environmental Agency's policy on the problem of endogenous endocrine disrupting chemicals-Environmental Hormones Strategic Plan SPEED'98-". Disclose a list of suspected chemicals, including alkylphenols, bisphenol A, tributyltin, triphenyltin, and di-2-phthalic acid.
67 types of compounds including ethylhexyl, butylbenzyl phthalate, di-n-butyl phthalate, dicyclohexyl phthalate, diethyl phthalate, di-2-ethylhexyl adipate, styrene dimer, styrene trimer, etc. Cadmium, lead and mercury are mentioned in (1). In this specification, the term “exogenous endocrine disrupting chemical” refers to 67 kinds of chemicals listed in Table 3 above, published by the Environment Agency in May 1998, and remarks (1) in Table 3. 70 chemicals, including the listed cadmium, lead and mercury. However, this definition is based on the state of the art at the time of filing the present application in order to clarify the present invention, and is not intended to be essentially limited only to these. Therefore, when a new substance that can be an endocrine disrupting substance and is found to be a substance other than the above 70 kinds, or among the 70 kinds of chemical substances that are suspected to have an endocrine disrupting action, it has an endocrine disrupting action. If it turns out that something is not the case, the content of the invention should be considered accordingly.

[0008] It goes without saying that it is important to reduce industrial use as much as possible in order to avoid the danger of these chemicals being released into the environment, even in trace amounts. However, the fact that these chemicals have been widely used in industrial products also means that their industrial advantages are widely recognized. The fact that alkylphenols and bisphenol A are widely used in the field of coatings is that, for example, in the field of cationic electrodeposition coating, the technical system using the above-mentioned bisphenol A type epoxy resin has been almost completed, Is very high.

Accordingly, an electrodeposition coating composition has been developed which does not use exogenous endocrine disrupting chemicals such as alkylphenol and bisphenol A, and which can ensure and surpass the performance of conventional cationic electrodeposition coating compositions. To do so, once away from the technology that has been established in the field of conventional cationic electrodeposition coatings, based on a new technology, base resin,
It is necessary to develop a curing system and a surface conditioning functional agent.

[0010]

SUMMARY OF THE INVENTION In view of the above situation, the present invention does not use exogenous endocrine disrupting chemicals, so-called "environmental hormones", such as alkylphenols and bisphenol A. It is an object of the present invention to provide a cationic electrodeposition coating composition having excellent workability and workability.

[0011]

The present invention uses a novolak type epoxy resin instead of a conventional bisphenol A epoxy resin as a base resin in a cationic electrodeposition coating composition, and uses a conventional alkylphenol as a surface conditioning functional agent. Is a cationic electrodeposition coating composition containing no long-chain hydrocarbon group and exogenous endocrine disrupting chemicals. Hereinafter, the present invention will be described in detail.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The cationic electrodeposition coating composition of the present invention contains a base resin (A) having a novolak type epoxy resin as a skeleton. The novolak type epoxy resin is an epoxy resin manufactured without using bisphenol A as a raw material. As the novolak-type epoxy resin, various ones can be used, but a novolak-phenol-type polyepoxy resin and a novolac-cresol-type polyepoxy resin are preferable because polyfunctional groups for enhancing curability are easily used. Further, in the present invention, other than the above-mentioned epoxy resin, use of the epoxy resin produced without using bisphenol A as a raw material does not hinder use. Examples of such an epoxy resin include polyglycidyl acrylate; polyglycidyl ether of aliphatic polyol or polyether polyol; and polyglycidyl ester of polybasic carboxylic acid.

The number average molecular weight of the base resin (A) is 5
It is preferably from 00 to 20,000. When the number average molecular weight is less than 500, the coating efficiency of the cationic electrodeposition coating becomes poor, and when it exceeds 20,000, a good film cannot be formed on the surface of the object to be coated. A more preferable number average molecular weight can be set according to the resin skeleton. For example, in the case of a novolak phenol type epoxy resin or a novolak cresol type epoxy resin, the number average molecular weight is preferably 700 to 5,000.

In the present invention, a sulfonium group (a) and a propargyl group (b) are introduced into the base resin (A) having the above-mentioned epoxy resin as a skeleton via an epoxy group of the epoxy resin forming the above-mentioned skeleton. ing.

The base resin having the above-mentioned epoxy resin as a skeleton may contain both a sulfonium group (a) and a propargyl group (b) in one molecule, but this is not always necessary. May contain at least one of a sulfonium group (a) and a propargyl group (b). In the latter case, the base resin as a whole contains all of these functional groups.

The above sulfonium group (a) is a hydrating functional group of the cationic electrodeposition coating composition of the present invention. When a voltage or current exceeding a certain level is applied during the electrodeposition coating process, the sulfonium group (a) undergoes an electrolytic reduction reaction on the electrode to lose the ionic group and irreversibly become nonconductive as shown below. can do. This is considered to be the reason that the cationic electrodeposition coating composition can exhibit high throwing power.

[0017]

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In this electrodeposition coating process, it is considered that an electrode reaction is caused, and the generated hydroxide ion is retained by the sulfonium group (a), so that an electrogenerated base is generated in the electrodeposited film. Can be This electrogenerated base can convert a propargyl group (b) having low reactivity due to heating existing in the electrodeposited film into an allene bond having high reactivity due to heating.

The content of the sulfonium group (a) in the base resin (A) is 10 to 3 per 100 g of resin solid content.
00 mmol. If it is less than 10 mmol / 100 g, sufficient throwing power and curability cannot be exhibited, and hydration properties and bath stability deteriorate. 300mm
When the amount exceeds ol / 100 g, the deposition of the coating film on the surface of the substrate is poor. In the case of a novolak phenol type epoxy resin or a novolak cresol type epoxy resin, the amount is more preferably from 10 to 250 mmol, even more preferably from 10 to 150 mmol, per 100 g of the resin solid content.

The propargyl group (b) is converted into an allene bond as described above to improve the reactivity, and constitutes a curing system having no volatile matter different from conventionally used blocked isocyanates. be able to. For unknown reasons, the sulfonium group (a)
By coexisting with, the throwing power of the electrodeposition coating composition can be further improved.

The content of the propargyl group (b) in the base resin (A) is 10 to 485 per 100 g of the resin solid content, after satisfying the conditions for the content of each functional group described later.
mmol. If it is less than 10 mmol / 100 g, sufficient curability cannot be exhibited, and 485 mm
When the amount exceeds ol / 100 g, hydration stability when used as a cationic electrodeposition coating composition may be adversely affected. In the case of a novolak phenol type epoxy resin or a novolak cresol type epoxy resin, the amount is preferably 20 to 375 mmol per 100 g of the solid content of the resin composition.

Incidentally, less than 50% of the propargyl groups (b) contained in the base resin (A) may be replaced by unsaturated double bonds. In addition, in this specification, an unsaturated double bond means a carbon-carbon double bond.

In the cationic electrodeposition coating composition of the present invention,
In addition to the base resin (A), a novolak type epoxy resin is used as a skeleton, and a sulfonium group (a) and a carbon number of 3
And at least one of organic groups and propargyl groups having an unsaturated double bond at the terminal (c) and C8
And a number average molecular weight of 700 to 24 containing an aliphatic hydrocarbon group (d) which may contain an unsaturated double bond in the chain.
5000 resins (B) are blended. In addition, in this specification, an organic group shall mean a hydrocarbon group which may contain an ester bond or an ether bond.

In the resin (B), the epoxy resin serving as the skeleton may be the same type as the base resin (A) or may be a different type. That is, for example, both the base resin (A) and the resin (B) may be a novolac cresol type epoxy resin or a novolak phenol type epoxy resin, and the base resin (A)
One of the resins (B) may be a novolac cresol type epoxy resin and the other may be a novolak phenol type epoxy resin.

The content of the sulfonium group (a) in the resin (B) is preferably 10 to 300 mmol per 100 g of the solid content of the resin (B). 10m
If it is less than 100 mol / 100 g, sufficient throwing power and curability cannot be exhibited, and hydration properties and bath stability deteriorate. If it exceeds 300 mmol / 100 g,
Precipitation of the film on the surface of the substrate is poor. Resin solids 10
More preferably, it is 10 to 250 mmol, more preferably 10 to 150 mmol per 0 g.

At least one of the above-mentioned organic group having 3 to 7 carbon atoms and a propargyl group having an unsaturated double bond at the terminal and (c) acts as a crosslinkable functional group, and The propargyl group (b) can react with the modified allene bond. The content of at least one of the organic group having 3 to 7 carbon atoms and a propargyl group having an unsaturated double bond at the terminal thereof and (c) is 10 to 315 mmol per 100 g of the solid content of the resin (B). Is preferred. If it is less than 10 mmol / 100 g, sufficient curability cannot be exhibited even when used in combination with another resin or curing agent, and 315
If the amount exceeds mmol / 100 g, the impact resistance becomes insufficient. More preferably, the amount is 20 to 295 mmol per 100 g of resin solids.

The aliphatic hydrocarbon group (d) having 8 to 24 carbon atoms and optionally containing an unsaturated double bond in the chain functions as a soft segment in the electrodeposition coating film. Therefore,
The resin (B) can exert an action as a surface conditioning agent. This plays the role of the alkylphenol contained in the conventional electrodeposition coating composition, and is an alternative.

The aliphatic hydrocarbon group (d) is not particularly limited, and may be a linear, branched, or cyclic hydrocarbon group other than the aromatic hydrocarbon group. A bond may be included in the chain. Preferably, it is a linear or branched hydrocarbon group having a carbon-carbon double bond in the chain. Such groups can be derived from the corresponding aliphatic hydrocarbon compound that contains these groups. Specific examples of the compound having such an aliphatic hydrocarbon group will be described later in detail.

The aliphatic hydrocarbon group (d) having 8 to 24 carbon atoms and optionally containing an unsaturated double bond in the chain is introduced via an ether bond formed by reacting with an epoxy group. Wherein the carbon number is counted from the carbon atom bonded to the oxygen atom of the ether bond. The content of the aliphatic hydrocarbon group (d) is preferably 80 to 350 mmol per 100 g of the resin solid content of the resin (B). If it is less than 80 mmol / 100 g, the surface conditioning effect and the improvement of impact resistance are insufficient, and the
If it exceeds mol / 100 g, the handleability of the resin composition becomes difficult. 100-300m per 100g of resin solids
More preferably, it is mol.

In the resin (B), the sulfonium group (a), at least one of an organic group having 3 to 7 carbon atoms and a propargyl group having an unsaturated double bond at the terminal (c), and a carbon number of 8 to 7 carbon atoms. The total content of the aliphatic hydrocarbon group (d) which may contain an unsaturated double bond in the chain is 500 mm per 100 g of the solid content of the resin (B).
ol or less. If it exceeds 500 mmol, the resin may not be actually obtained or the desired performance may not be obtained. More preferably, it is 400 mmol or less.

The amount of the resin (B) is preferably 5 to 45 parts by weight based on 100 parts by weight of the base resin (A). If the amount is less than 5 parts by weight, the effect of the compounding is not sufficient, and if it is more than 45 parts by weight, the effect according to the compounding amount cannot be obtained. More preferably, it is 20 to 35 parts by weight.

In this case, the cationic electrodeposition coating composition prepared by blending the resin (B) contains a sulfonium group (a), an unsaturated double bond having 8 to 24 carbon atoms in the chain. The total content of the aliphatic hydrocarbon group (d) which may be substituted and at least one kind of an organic group having 3 to 7 carbon atoms and a propargyl group having an unsaturated double bond at the terminal (c) is a resin solid content. The content of the aliphatic hydrocarbon group (d), which is 500 mmol or less per 100 g and may have an unsaturated double bond having 8 to 24 carbon atoms in the chain,
It is preferably set to be 3 to 30% by weight of the resin solid content.

The method for producing the resin (B) will be described below. That is, it has at least two epoxy groups in one molecule, and reacts with an epoxy resin produced without using bisphenol A, for example, a novolak phenol type polyepoxy resin or a novolak cresol type polyepoxy resin. Compound (I) having a functional group and a propargyl group or an organic group having 3 to 7 carbon atoms and having an unsaturated double bond at the terminal, and a functional group reacting with an epoxy group and an unsaturated double bond having 8 to 24 carbon atoms The compound (II) having an aliphatic hydrocarbon group which may contain a bond in the chain is reacted to form a propargyl group or a compound having 3 to 3 carbon atoms.
7, an organic group having an unsaturated double bond at the terminal and a carbon number of 8
(1) to obtain an epoxy resin composition containing an epoxy resin composition having an aliphatic hydrocarbon group which may contain an unsaturated double bond in the chain, the propargyl group or carbon obtained in the step (1). Epoxy resin containing an organic group having an unsaturated double bond at the terminal of number 3 to 7 and an aliphatic hydrocarbon group having 8 to 24 carbon atoms and having an unsaturated double bond in the chain. It can be suitably manufactured by the step (2) of introducing a sulfonium group into a residual epoxy group in the composition.

As the compound having a functional group which reacts with the epoxy group and a propargyl group or an organic group having 3 to 7 carbon atoms and having an unsaturated double bond at the terminal (hereinafter, referred to as "compound (I)"), For example, a compound having both a functional group that reacts with an epoxy group such as a hydroxyl group or a carboxyl group and a propargyl group or an organic group having 3 to 7 carbon atoms and having an unsaturated double bond at the terminal may be used. A compound having a propargyl group and a hydroxyl group such as propargyl alcohol; a compound having a propargyl group and a carboxyl group such as propargylic acid; 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, Hydroxybutyl acrylate, hydroxybutylmeth It can be mentioned acrylic acid, methacrylic acid, a compound having an unsaturated double bond and a carboxyl group, such as ethacrylic acid; acrylate, allyl alcohol, a compound having an unsaturated double bond and a hydroxyl group, such as methacrylic alcohols.

Of these, as the compound having a functional group that reacts with an epoxy group and a propargyl group, propargyl alcohol is preferable from the viewpoint of easy availability.

A compound having an aliphatic hydrocarbon group having a functional group which reacts with the epoxy group and an unsaturated double bond having 8 to 24 carbon atoms in the chain (hereinafter referred to as "compound (II)") ) Is, for example, a functional group that reacts with an epoxy group such as a hydroxyl group or a carboxyl group and a C8-C
To 24, an aliphatic hydrocarbon group which may contain an unsaturated double bond in the chain.
Specifically, as those having a hydroxyl group and an aliphatic hydrocarbon group, for example, octanol, nonanol, decyl alcohol, undecanol, dodecanol, tridecanol, tetradecanol, pentadecanol, hexadecanol, heptadecanol, octadecanol Decanol, nonadecanol, eicosanol, docosanol, 2-propyl-1-pentanol, 2,4,4-trimethyl-1
-Pentanol, 2-ethyl-1-hexanol, 3,
3,5-trimethyl-1-hexanol, 3,7-dimethyl-1-octanol, 2-octanol, 3-octanol, 2-nonanol, 2-decanol, 4-decanol, 2-undecanol, 2-dodecanol, 2-
Tetradecanol, 2-hexadecanol, 6-methyl-2-heptanol, 4-methyl-3-heptanol,
2,6-dimethyl-4-heptanol, 3-ethyl-
Long-chain aliphatic alcohols such as 2,2-dimethyl-3-pentanol and 3,7-dimethyl-3-octanol; 1-
Octen-3-ol, β-citronellol, 3-nonen-1-ol, 5-decene-1-ol, 9-decene-1-ol, ω-undecylenyl alcohol, 7-dodecyl-1-ol, 7 -Tetradecene-1-ol,
9-tetradecene-1-ol, 11-tetradecene-
1-ol, 11-hexadecene-1-ol, oleyl alcohol, 2,4-dimethyl-2,6-heptadien-1-ol, phytol, nerol, geraniol, 8,10-dodecadien-1-ol, farnesol, 6 And long-chain aliphatic alcohols containing unsaturated double bonds such as -methyl-5-hepten-2-ol.

Examples of those having a carboxyl group and an aliphatic hydrocarbon group include octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, lauric acid, tridecanoic acid, myristic acid, pentadecanoic acid, palmitic acid, heptadecanoic acid, and stearin Long chain fatty acids such as acid, nonadecanoic acid, eicosanoic acid, heneicosanoic acid, docosanoic acid, tricosanoic acid, and tetracosanoic acid; 2-ethylhexenoic acid, 2-octanoic acid, citronellic acid, undecylenic acid, myristoleic acid, palmitoleic acid, and olein Acid, linoleic acid, ricinoleic acid, elaidic acid, 11-eicosenoic acid, erucic acid, nervonic acid, linolenic acid, 11,14-eicosatrienoic acid, arachidonic acid, 5,8,11,14,17-
Eicosapentaenoic acid, 4,7,10,13,16,1
9-docosahexaenoic acid, 2-propylpentanoic acid, 2
-Synthetic or natural unsaturated fatty acids such as ethylhexanoic acid, linseed oil and soybean oil.

The above compound (II) is preferably a compound having a carboxyl group in consideration of reactivity.
Unsaturated fatty acids are more preferred.

In the above step (1), the compound (I) and the compound (II) may be mixed in advance in a mixing ratio such that the desired functional group content is obtained, and the mixture may be subjected to a reaction, or And the compound (I) and the compound (II) may be separately subjected to the reaction. In addition, the functional group reacting with the epoxy group of the compound (I) and the compound (I)
The functional group which reacts with the epoxy group of I) may be the same or different.

The reaction conditions in the step (1) are usually several hours at room temperature or 80 to 140 ° C. In addition, if necessary, a known component necessary for advancing a reaction such as a catalyst or a solvent can be used. 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.

In the step (2), a sulfonium group is introduced into the remaining epoxy group in the epoxy resin composition obtained in the step (1). The sulfonium group can be introduced by reacting a sulfide / acid mixture with an epoxy group to introduce and sulfonate a sulfide, or after introducing a sulfide, further adding an acid or methyl fluoride, methyl chloride, methyl bromide, or the like. The reaction can be performed by a method of performing a sulfonium conversion reaction of the introduced sulfide with an alkyl halide or the like and, if necessary, performing anion exchange. From the viewpoint of the availability of reaction raw materials, a method using a sulfide / acid mixture is preferred.

The sulfide is not particularly limited.
For example, aliphatic sulfide, mixed aliphatic-aromatic sulfide, aralkyl sulfide, cyclic sulfide and the like can be mentioned. Specifically, for example, diethyl sulfide, dipropyl sulfide, dibutyl sulfide, dihexyl sulfide, diphenyl sulfide, ethyl phenyl 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.

The acid is not particularly limited.
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.

The mixing ratio of the sulfide and the acid in the sulfide / acid mixture is generally preferably about 100/60 to 100/100 in terms of molar ratio of sulfide / acid.

The reaction of the above step (2) is carried out, for example, by combining the epoxy resin composition obtained in the above step (1) with, for example, a predetermined amount of the above sulfide set to have the above-mentioned sulfonium group content and the above-mentioned sulfide. The mixture with an acid is mixed with 5 to 10 times the mole of water of the sulfide used,
It can be performed by stirring at ~ 90 ° C for several hours. The end point of the reaction may be based on the remaining acid value being 5 or less. Confirmation of sulfonium group introduction in the obtained resin composition can be performed by potentiometric titration.

In the production method of the present invention, as described above, by introducing the sulfonium group after the introduction of the propargyl group, the decomposition of the sulfonium group due to heating can be prevented.

The method for producing the base resin (A) can be carried out according to the above-mentioned production method.

In the cationic electrodeposition coating composition of the present invention, the use of a curing agent is not necessarily required since the above-mentioned base resin (A) and resin (B) themselves have curability. However, it may be used to further improve the curability. Examples of such a curing agent include compounds having a plurality of at least one of a propargyl group and an unsaturated double bond, for example, polyepoxides such as novolak phenol, pentaerythritol tetraglycidyl ether, and the like, propargyl alcohol, and the like. And compounds obtained by subjecting a compound having an unsaturated double bond such as acrylic acid to an addition reaction with a compound having a propargyl group.

In the cationic electrodeposition coating composition of the present invention, a curing catalyst can be used if desired. The curing catalyst is not particularly limited.For example, nickel, cobalt, copper, manganese, palladium, a transition metal such as rhodium, a ligand such as cyclopentadiene or acetylacetone, or a carboxylic acid such as acetic acid bound thereto. And the like. Of these, copper acetylacetone complex and copper acetate are preferred. Further, when a transition metal compound which can be converted into acetylide such as copper, silver, barium or the like, for example, a compound such as copper acetylacetone is used, a propargyl group and acetylide can be formed, which is preferable from the viewpoint of curability. The compounding amount of the curing catalyst is 0.1 to 20 mm per 100 g of the cationic electrodeposition coating composition resin solid content.
ol is preferred.

The cationic electrodeposition coating composition of the present invention may further contain an amine. The addition of the amine increases the conversion rate of sulfonium groups to sulfide by electrolytic reduction in the electrodeposition process. The amine is not particularly limited, and examples thereof include primary to tertiary monofunctional and polyfunctional aliphatic amines, alicyclic amines, and aromatic amines. Of these,
Water-soluble or water-dispersible ones are preferred, for example, alkylamines having 2 to 8 carbon atoms such as monomethylamine, dimethylamine, trimethylamine, triethylamine, propylamine, diisopropylamine, tributylamine; monoethanolamine, dimethanolamine, Methylethanolamine, dimethylethanolamine, cyclohexylamine, morpholine, N-methylmorpholine, pyridine, pyrazine, piperidine, imidazoline,
Imidazole and the like can be mentioned. 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 their excellent water dispersion stability.

The above amine can be directly incorporated into the cationic electrodeposition coating composition of the present invention. In a conventional neutralized amine-based cationic electrodeposition coating composition, when a free amine is added, the neutralized acid in the resin is deprived, and the stability of the electrodeposition solution is significantly deteriorated. Is
Such inhibition of bath stability does not occur.

The amount of the amine added is 0.3 to 25 meq per 100 g of the resin solid content of the cationic electrodeposition coating composition.
Is preferred. If it is less than 0.3 meq / 100 g, a sufficient effect on throwing power cannot be obtained, and 2
If it exceeds 5 meq / 100 g, the effect corresponding to the added amount cannot be obtained, which is uneconomical. More preferably, 1 to
It is 15 meq / 100 g.

The cationic electrodeposition coating composition of the present invention may contain, if necessary, other components used in ordinary cationic electrodeposition coating compositions. The other components are not particularly limited, for example, a pigment, a pigment dispersion resin,
Coating additives such as surfactants, antioxidants, and ultraviolet absorbers can be used. It is necessary that these components also contain no endogenous endocrine disrupting chemicals.

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 preventing pigments such as aluminum phosphomolybdate;
Examples thereof include those generally used in cationic electrodeposition coating compositions such as extenders such as kaolin, clay, and talc. The compounding amount of the pigment is preferably 0 to 50% by weight as a solid content in the cationic electrodeposition coating composition.

The pigment-dispersed resin is not particularly limited, and a commonly used pigment-dispersed resin can be used.

In the cationic electrodeposition coating composition of the present invention, if necessary, the above-mentioned components are mixed with predetermined amounts of the above-mentioned base resin (A) and the above-mentioned resin (B) and dissolved or dispersed in water. Can be obtained. When it is used for cationic electrodeposition coating, it is preferably prepared so as to have a bath solution having a nonvolatile content of 10 to 30%. Further, a propargyl group in the cationic electrodeposition coating composition, an organic group having 3 to 7 carbon atoms and having an unsaturated double bond at the terminal, and an unsaturated double bond having 8 to 24 carbon atoms contained in the chain. It is preferable that the content of the aliphatic hydrocarbon group and the sulfonium group which may be included be adjusted so as not to deviate from the above range.

The cationic electrodeposition coating composition of the present invention is substantially free of exogenous endocrine disrupting chemicals, especially alkylphenol and bisphenol A. That is, the cationic electrodeposition coating composition of the present invention comprises the base resin (A)
Not only those not using bisphenol A as the raw material of the above (A) but also those using bisphenol A in the resin (B) are not applied. In addition, other additives that do not use exogenous endocrine disrupting chemicals are blended, and in particular, there is no use of a surface conditioner using an alkylphenol. In other words, in the electrodeposition coating composition of the present invention, there is no need to use exogenous endocrine disrupting chemicals in the raw materials thereof, and the electrodeposition coating composition of the present invention does not contain any exogenous substances. Contains no endocrine disrupting chemicals.

When electrodeposition coating is carried out using the cationic electrodeposition coating composition of the present invention, the object to be coated is not particularly limited as long as it is conductive, and examples thereof include iron plate, steel plate, aluminum plate and the like. Those obtained by subjecting them to surface treatment, molded products thereof, and the like can be given.

The electrodeposition coating is carried out by using the object to be coated as a cathode and applying a voltage of usually 50 to 450 V between the anode and the anode. If the applied voltage is less than 50 V, electrodeposition becomes insufficient,
If the voltage exceeds 0 V, 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 coating can be formed on the entire object without causing a sharp increase in film thickness in the electrodeposition process. it can.

The bath temperature of the cationic electrodeposition coating composition when the above voltage is applied is usually preferably from 10 to 45 ° C.

The electrodeposition step comprises (i) a step of immersing the object to be coated in the cationic electrodeposition coating composition, and (ii) a voltage is applied between the above-mentioned object to be used as a cathode and an anode to deposit a coating. It is preferable that the method further comprises the step of: (iii) increasing the electric resistance per unit volume of the coating by further applying a voltage to the deposited coating.
The time for applying the voltage varies depending on the electrodeposition conditions, but can be generally 2 to 4 minutes.

The electrodeposited film obtained as described above may be used as it is or after washing with water after completion of the electrodeposition process.
The coating is cured by baking at 60 ° C., preferably 160-220 ° C. for 10-30 minutes to complete the coating.

When the cationic electrodeposition coating composition of the present invention is used, the thickness of the cured electrodeposition coating film is preferably 10 to 25 μm. If it is less than 10 μm, the rust prevention is insufficient, and if it exceeds 25 μm, the paint is wasted. In the cationic electrodeposition coating composition of the present invention, by the above-described electrolytic reduction reaction, the film deposited on the surface of the object to be coated by electrodeposition becomes nonconductive, and as a result, throwing power is dramatically improved. . Therefore, even when the thickness of the coating film is in the above range, a uniform coating film can be formed on the entire object to be coated, and sufficient rust prevention can be exhibited.

The substrate on which the coating film thus obtained is formed is further coated with a necessary intermediate coat and / or top coat according to the purpose. For example, in the case of an automobile outer panel, generally, a solvent type for imparting chipping resistance, an aqueous or powdery intermediate coating is applied and baked, and then a base coating is applied. It is painted by the so-called wet-on-wet method of applying a clear paint without curing,
Thereafter, a two-coat one-bake coating method of simultaneously baking these coating films is applied. In this case, it is preferable to use an aqueous paint as the base paint and a powder paint as the clear paint in consideration of environmental problems. In addition, it is obvious that the present invention can be used for a solid paint to which the one-coat coating method is applied.

[0065]

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.

Production Example 1Sulfonium group, propargyl
For cationic electrodeposition paints containing copper and copper acetylide groups
Production of fat composition  Cresol novolak type epoxy with epoxy equivalent of 200.4
Xyresin (Epotote YDCN-701 (trade name), East
Propargyl alcohol 2 in 100.0 g
3.6 g of dimethylbenzylamine 0.3 g with a stirrer,
Separable with thermometer, nitrogen inlet and reflux condenser
Add to the flask, raise the temperature to 105 ° C, and react for 3 hours
Resin having propargyl group with epoxy equivalent of 1580
A composition was obtained. This was added to copper acetylacetonate.
5 g was added and reacted at 90 ° C. for 1.5 hours. proton
In (1H) NMR, a part of the terminal hydrogen of the added propargyl group is
It was confirmed that it had disappeared (14 mmol / 100
g Resin composition solids equivalent). In addition, 1- (2-
(Hydroxyethylthio) -2,3-propanediol 1
0.6 g, glacial acetic acid 4.7 g, deionized water 7.0 g
React for 6 hours while keeping the temperature at 75 ° C, and the residual acid value is 5 or less
After confirming that it is the same as above, add 43.8 g of deionized water.
Thus, a desired resin composition solution was obtained. Solid content of this product
The degree is 70.0% by weight, the sulfonium value is 28.0 mmo
1/100 g varnish. Number average molecular weight (polystyrene
GPC (lens conversion) was 2,433.

Production Example 2Sulfonium group, propargyl
Electrodeposition Coating Containing Group and Long Chain Unsaturated Fatty Acid Residue
Of resin composition for food  Cresol novolak type epoxy with epoxy equivalent of 200.4
Xyresin (Epotote YDCN-701 (trade name), East
Propargyl alcohol 1 in 100.0 g
3.5 g, dimethylbenzylamine 0.2 g stirrer,
Separable with thermometer, nitrogen inlet and reflux condenser
Add to the flask, raise the temperature to 105 ℃, let react for 1 hour,
Resin containing propargyl group having epoxy equivalent of 445
A composition was obtained. 50.6 g of linoleic acid was added to this
0.1 g of dimethylbenzylamine, and
The reaction was continued for 3 hours at
Trees containing propargyl groups and long-chain unsaturated fatty acid residues
A fat composition was obtained. In this, 1- (2-hydroxyd
(Tilthio) -2,3-propanediol 10.6 g, ice
Add 4.7 g of acetic acid and 7.0 g of deionized water and keep at 75 ° C.
Reaction for 6 hours while heating, residual acid value is 5 or less
After confirming, 62.9 g of deionized water was added, and the desired tree was added.
A fat composition solution was obtained. Its solids concentration is 69.3.
Weight%, sulfonium value is 23.5mmol / 100g
It was a varnish. Number average molecular weight (GP in terms of polystyrene)
C) was 3106.

Production Example 3Sulfonium group, propargyl
Resin composition for cationic electrodeposition coatings containing vinyl and vinyl groups
Manufacture of goods  Cresol type epoxy resin with epoxy equivalent of 200.4
(Epototo YDCN-701 (trade name), Toto Kaseisha
10.0 g of propargyl alcohol in 100.0 g
g, allyl alcohol 10.5 g, hydroquinone 0.
05 g and dimethylbenzylamine 0.3 g with a stirrer
Separable burger equipped with a thermometer, nitrogen inlet tube and reflux condenser
In addition to Lasco, raise the temperature to 105 ° C and react for 3 hours.
It contains a propargyl group and a vinyl group having a
The obtained resin composition was obtained. In addition to this,
Roxyethylthio) -2,3-propanediol10.
75 g with 6 g, 4.7 g of glacial acetic acid and 7.0 g of deionized water
The reaction was continued for 6 hours while keeping the temperature at
After confirming that the solution, add 45 g of deionized water and
A resin solution was obtained. Its solids concentration is 70.9 weight
%, Sulfonium value is 27.6 mmol / 100 g crocodile
Was. Number average molecular weight (GPC in terms of polystyrene)
Was 2439.

Production Example 4Sulfonium group, propargyl
Electrodeposition Coating Containing Group and Long Chain Saturated Fatty Acid Residue
Of resin composition for plastics  Cresol novolak type epoxy with epoxy equivalent of 200.4
Xy resin (Epototo YDCN-701, Toto Kasei Co., Ltd.)
Propargyl alcohol 5.1 g to 100.0 g)
0.1 g of dimethylbenzylamine was stirred with a stirrer,
In a separable flask equipped with a nitrogen inlet tube and a reflux condenser
In addition, the temperature was raised to 105 ° C and reacted for 1 hour.
A propargyl group-containing resin composition having an amount of 260
Was. Add 94.1 g of stearic acid, additional dime
0.2 g of tylbenzylamine was added, and 4
The reaction was continued for a
A resin containing a gil group and a long-chain saturated fatty acid residue was obtained.
In addition, 1- (2-hydroxyethylthio) -2,
10.6 g of 3-propanediol, 4.7 g of glacial acetic acid,
Add 7.0 g of deionized water, and keep at 75 ° C for 6 hours.
After confirming that the residual acid value is 5 or less,
78.1 g of ionic water was added to obtain a desired resin composition solution.
Was. It has a solid content of 70.1% by weight,
The um value was 19.6 mmol / 100 g varnish.
The number average molecular weight (polystyrene equivalent GPC) is 3689
there were.

Example 1 100.0 g of the resin composition for a cationic electrodeposition coating containing the sulfonium group, propargyl group and copper acetylide group obtained in Preparation Example 1, 100.0 g of the sulfonium group, propargyl group obtained in Preparation Example 2, 43.2 g of a resin composition for a cationic electrodeposition coating composition containing a long-chain unsaturated fatty acid residue and 156.8 g of deionized water were added, and the mixture was stirred for 1 hour with a high-speed rotary mixer, followed by addition of 373.3 g of deionized water. An aqueous solution was prepared so as to have a solid content of 15% by weight to obtain a cationic electrodeposition coating composition.

Example 2 Resin composition 1 for cationic electrodeposition coating containing sulfonium group, propargyl group and vinyl group obtained in Production Example 3
19.9 g, nickel acetylacetonate (1.0 g), deionized water (157) were added to 21.4 g of the resin composition for a cationic electrodeposition coating composition containing a sulfonium group, a propargyl group and a long-chain saturated fatty acid residue obtained in Production Example 4. 0.7 g,
After stirring with a high-speed mixer for 1 hour, 37
3.3 g was added thereto, and an aqueous solution was prepared such that the solid component concentration became 15% by weight to obtain a cationic electrodeposition coating composition.

[0072]Evaluation  Cationic electrodeposition coating compositions obtained in Examples and Comparative Examples
Cold-rolled steel sheet treated with zinc phosphate (JIS G3
141 SPCC-SD, Surfdyne SD-5000
(Trade name, manufactured by Nippon Paint Co., Ltd.)
Electrodeposition coating was performed using the container as an anode. Electroplating bath
, Washed with water, baked at 160 ° C for 20 minutes,
An electrodeposition coating was obtained.

It was confirmed that the electrodeposition coating composition obtained in the example had a uniform thickness of the coating film and had high throwing power without any uncoated portions. In addition, good bath stability was also confirmed.

The electrodeposited coating film thus obtained was placed in a Soxhlet extractor, and acetone / methanol = 1/1.
The mixture was extracted for 6 hours under reflux conditions using the mixed solution (weight ratio), and the gel fraction of the cured film was calculated by the following equation. Gel fraction (%) = [weight of coating film after extraction (%) / weight of coating film before extraction (%)] × 100

As a result, the gel fraction of the electrodeposited coating film obtained from the cationic electrodeposition coating composition of Example 1 was 96%, and the electrodeposition coating obtained from the cationic electrodeposition coating composition of Example 2 was 96%. The gel fraction of the membrane was 97%, and all were judged to be acceptable.

[0076]

Since the cationic electrodeposition coating composition of the present invention has the above-mentioned constitution, it is possible to use an epoxy resin which does not use exogenous endocrine disrupting chemicals as a raw material. Therefore, it is possible to reduce the use of exogenous endocrine disrupting chemicals in the industrial field. Further, since the cationic electrodeposition coating composition of the present invention contains substantially no alkylphenol and bisphenol A, it is possible to avoid the diffusion of exogenous endocrine disrupting chemicals accompanying the use of the electrodeposition coating. Moreover, high throwing power equal to or higher than that of the conventional cationic electrodeposition coating composition can be realized, good bath stability can be ensured, and excellent cured coating physical properties can be exhibited. Therefore, it is possible to prevent the extrinsic endocrine disrupting chemicals from diffusing into the environment without lowering the required performance of the conventional cationic electrodeposition coating composition, and the environmental and industrial requirements are high. Become compatible at the level.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Ichiro Kawakami 19-17 Ikedanakacho, Neyagawa-shi, Osaka Inside Nippon Paint Co., Ltd. (72) Inventor Takao Saito 19-17 Ikedananakacho, Neyagawa-shi, Osaka Nippon Paint F term in reference company (reference) 4J038 DB401 DB402 KA03 KA08 NA12 NA27 PA04 PB07 PC02

Claims (2)

[Claims] 1. A cationic electrodeposition coating composition comprising no endogenous endocrine disrupting chemicals. 2. The cationic electrodeposition coating composition according to claim 1, wherein the endogenous endocrine disrupting chemicals are bisphenol A and alkylphenol.