JP3519702B2 - Cationic resin composition - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cationic resin composition, and more particularly to a cationic resin composition capable of forming a cured coating film having excellent corrosion resistance and suitability for cationic electrodeposition coating on rustproof steel plates.

[0002]

BACKGROUND OF THE INVENTION Cationic resin compositions are mainly used as a cationic electrodeposition coating for a wide range of applications including undercoating of automobile bodies, and those having various properties have been developed. As a conventional cationic coating composition, for example, a modified epoxy obtained by internally plasticizing an epoxy resin containing an amino group and / or a quaternary ammonium salt group as a hydrophilic group with a plasticizer such as polyamide, polyester or polyether. A resin is used as a vehicle component, and a rust preventive pigment, for example, a lead compound such as lead chromate, basic lead silicate, or strontium chromate, or a chromium compound is added, which has excellent corrosion resistance and rust prevention. A coating composition having improved electrodeposition coating suitability and adhesion to a steel sheet has been proposed. However, in recent years, from the viewpoint of pollution problems, the use of harmful compounds such as lead compounds and chromium compounds has been restricted, and it is possible to improve the anticorrosion property of a coating film even if such a harmful compound is not blended. It is desired to develop a technology that can do this.

On the other hand, an epoxy resin internally plasticized with a plasticizer such as polyamide, polyester or polyether tends to lower the corrosion resistance of the coating film, so that an epoxy resin containing no plastic modifier should be used. Although it is considered that the corrosion resistance is improved by this, there is a problem that the suitability for electrodeposition coating on the rustproof steel plate is deteriorated. In order to solve such a problem, it is proposed to add, for example, a polyol resin such as polyester polyol, polyether polyol, polyurethane polyol, or acrylic polyol; a polymer such as polyolefin such as polybutadiene or polyethylene as a plasticizer of epoxy resin. However, these materials do not have sufficient compatibility with epoxy resin and are not very effective in improving the suitability for anti-rust steel plate, etc., and when added in a large amount, the corrosion resistance of the coating film decreases. There's a problem.

The main object of the present invention is to form a coating film excellent in both anticorrosion property and suitability for rustproof steel plate without using harmful compounds such as lead compounds and chromium compounds, especially cationic electrodeposition. It is an object of the present invention to provide a cationic resin composition based on an epoxy resin which is useful as a paint.

[0005]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that, as a vehicle component in a cationic resin composition, a certain kind of amino group-containing epoxy resin was used as a vehicle component of a specific polyol-modified amino group. The present invention has been completed by finding that the above object can be achieved by combining with a group-containing epoxy resin and a blocked polyisocyanate curing agent.

Thus, the present invention provides the following components: (A) Amino group-containing epoxy resin obtained by adding the amino group-containing compound (a-2) to the epoxy resin (a-1) having an epoxy equivalent of 400 to 3000. , (B) an epoxy resin (b-1) having an epoxy equivalent of 180 to 2,500, a polyol compound (b-) obtained by adding caprolactone to the amino group-containing compound (b-2) and the compound having a plurality of active hydrogen groups. 3) A polyol-modified amino group-containing epoxy resin obtained by reacting 3) and (C) a blocked polyisocyanate curing agent are contained, and the above component (A),
Containing 40 to 70% by weight of component (A), 5 to 40% by weight of component (B), and 10 to 40% by weight of component (C) based on the total solid content of (B) and (C). The present invention provides a cationic resin composition characterized by the following.

The cationic resin composition of the present invention will be described in more detail below. Amino group-containing epoxy resin (A) : The amino group-containing epoxy resin used as the component (A) in the cationic resin composition of the present invention is obtained by adding the amino group-containing compound (a-2) to the epoxy resin (a-1). The epoxy resin (a-1) is obtained by addition reaction.
Is 400 to 3000, preferably 450 to 2500,
More preferably it can have an epoxy equivalent weight in the range of 500-2200, and is generally 500-500.
0, especially 600-4500, more particularly 800-400
Those having a number average molecular weight in the range of 0 are suitable.

As such an epoxy resin (a-1), an epoxy resin obtained by reacting a polyphenol compound with an epihalohydrin, for example, epichlorohydrin, is particularly suitable from the viewpoint of the anticorrosive property of the coating film.

Examples of the polyphenol compound which can be used for forming the epoxy resin include bis (4-hydroxyphenyl) -2,2-propane (bisphenol A), 4,4-dihydroxybenzophenone and bis (4
-Hydroxyphenyl) methane (bisphenol F),
Bis (4-hydroxyphenyl) -1,1-ethane, bis (4-hydroxyphenyl) -1,1-isobutane,
Bis (4-hydroxy-tert-butyl-phenyl)
-2,2-propane, bis (2-hydroxynaphthyl)
Methane, tetra (4-hydroxyphenyl) -1,1,
2,2-ethane, 4,4-dihydroxydiphenyl sulfone (bisphenol S), phenol novolac, cresol novolac and the like can be mentioned.

The epoxy resin obtained by the reaction of a polyphenol compound and epichlorohydrin includes, among others, the following formulas derived from bisphenol A:

[0011]

[Chemical 1]

Those represented by are preferred.

Commercially available products of such epoxy resin are, for example, Epicoat 828 from Japan Epoxy Resin Co., Ltd.
Those sold under the trade names of EL, 1002, 1004, and 1007 are listed.

On the other hand, an amino group-containing compound (a-) which is a cation-providing component for introducing an amino group into the epoxy resin (a-1) to cationize the epoxy resin.
As 2), an amine compound containing at least one active hydrogen that undergoes an addition reaction with the epoxy group of the epoxy resin (a-1), for example, having at least one primary amino group or secondary amino group in the molecule. Suitable are, for example, mono- or di-alkylamines such as monomethylamine, dimethylamine, monoethylamine, diethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, monobutylamine, dibutylamine; Monoethanolamine, diethanolamine, mono (2-hydroxypropyl) amine, di (2-hydroxypropyl) amine, tri (2
-Hydroxypropyl) amine, monomethylaminoethanol, monoethylaminoethanol, and other alkanolamines; ethylenediamine, propylenediamine, butylenediamine, hexamethylenediamine, tetraethylenepentamine, pentaethylenehexamine, diethylaminopropylamine, diethylenetriamine, triethylenetetramine, etc. And the ketimine compounds of these polyamines; alkyleneimines such as ethyleneimine and propyleneimine; cyclic amines such as piperazine, morpholine and pyrazine.

The addition reaction of the above-mentioned amino group-containing compound to the epoxy resin (a-1) can be carried out by a method known per se, for example, the epoxy resin (a-1) is
For example, hydrocarbon solvents such as heptane, toluene, xylene, octane, mineral spirits; ester solvents such as ethyl acetate, n-butyl acetate, isobutyl acetate, ethylene glycol monomethyl ether acetate, ethylene glycol monobutyl ether acetate; methyl ethyl ketone, methyl Ketone solvents such as isobutyl ketone, diisobutyl ketone and cyclohexanone; methanol, ethanol, isopropanol, n-butanol,
alcohol solvents such as sec-butanol and isobutanol; in organic solvents such as ether solvents such as n-butyl ether, dioxane, ethylene glycol monomethyl ether and ethylene glycol monoethyl ether,
Amino group-containing compound (a-2) and about 80 to about 130 ° C
It can be carried out by reacting at the temperature of. The use ratios of the epoxy resin (a-1) and the amino group-containing compound (a-2) at that time are not strictly limited, and may be changed depending on the kind of the starting material used, the desired properties of the product, and the like. It can be changed, but usually (a-1) / (a
-2) with a weight ratio of 90/10 to 60/40, especially 85
The range of / 15 to 70/30 is preferable.

The amino group-containing epoxy resin (A) thus obtained is generally 30 to 100, preferably 40 to 8.
It can have an amine number in the range of 0. Polyol-modified amino group-containing epoxy resin (B) : The polyol-modified amino group-containing epoxy resin used as the component (B) in the cationic resin composition of the present invention is
To the epoxy resin (b-1), the amino group-containing compound (b-
2) and a polyol compound (b-3) obtained by adding caprolactone to a compound containing a plurality of active hydrogen groups
The epoxy resin (b-1) is obtained by reacting the above-mentioned epoxy resin (b-1) with 180 to 2500, preferably 200 to 2000, and more preferably 400 to 150.
Can have an epoxy equivalent weight in the range of 0, and
Those having a number average molecular weight in the range of at least 200, especially 400 to 4000, more particularly 800 to 2000 are suitable.

The epoxy resin (b-1) is also preferably the one obtained by reacting a polyphenol compound with epichlorohydrin, as in the above-mentioned epoxy resin.
For example, the epoxy resin (a-1) can be appropriately selected and used from those exemplified above.

The amino group-containing compound (b-2) used for introducing an amino group as a cationizable group into the epoxy resin (b-1) is the same as the epoxy resin (a-1). As the amino group-containing compound (a-2) used for introducing a group, those described above can be similarly used.

Further, in the present invention, the polyol compound (b-3) is reacted for the internal plasticization (modification) of the epoxy resin (b-1). As the polyol compound (b-3), a compound obtained by adding caprolactone to a compound having a plurality of active hydrogen groups (hereinafter referred to as "active hydrogen-compound") is used.

The active hydrogen group means an atomic group containing at least one active hydrogen and includes, for example, an alcoholic hydroxyl group, a primary amino group, a secondary amino group and the like. Then, as a compound containing a plurality of such active hydrogen groups in one molecule, that is, an active hydrogen-compound, for example, (i) a low molecular weight polyol, (ii) a linear or branched polyether polyol, (iii ) A linear or branched polyester polyol, (iv) an amine compound containing a primary amino group and / or a secondary amino group,
Alternatively, there may be mentioned a hydroxyamine compound having both a primary amino group and / or a secondary amino group and a hydroxyl group. These active hydrogen group-containing compounds (a) are generally 6
It can have a number average molecular weight in the range of 2 to 5,000, preferably 62 to 4,000, more preferably 62 to 1,500. Further, the active hydrogen-compound is preferably one containing at least 2 and less than 30, especially 2 to 10 active hydrogen groups per molecule on average.

The above-mentioned low molecular weight polyol (i) is a compound containing at least two alcoholic hydroxyl groups in one molecule, and specific examples thereof include ethylene glycol, propylene glycol and 1,3-butylene glycol. 1,4-butanediol, 1,6-hexanediol, diethylene glycol, dipropylene glycol,
Cyclohexane-1,4-dimethylol, neopentyl glycol, triethylene glycol, hydrogenated bisphenol A and other diols; glycerin, trimethylolethane, trimethylolpropane and other triols; pentaerythritol, α-methyl glycoside and other tetrols Hexols such as sorbitol and dipentaerythritol; octols such as sucrose.

The above linear or branched polyether polyol (ii) can have a number average molecular weight in the range of usually 62 to 10,000, preferably 62 to 2,000, and specifically, , For example, polythiethylene glycol, polypropylene glycol, polytetramethylene glycol, poly (ethylene propylene) glycol produced by a ring-opening addition reaction of alkylene oxide (eg, ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran, etc.) , Bisphenol A ethylene glycol ether, bisphenol A polypropylene glycol ether, and the like.

The above-mentioned linear or branched polyester polyol (iii) can have a number average molecular weight in the range of generally 200 to 10,000, preferably 200 to 3,000, and specifically, For example, those obtained by a polycondensation reaction of an organic dicarboxylic acid or its anhydride with an organic diol under the condition of an excess of the organic diol are mentioned. As the organic dicarboxylic acid used here, an aliphatic, alicyclic or aromatic dicarboxylic acid having 2 to 44 carbon atoms, particularly 4 to 36 carbon atoms, for example, adipic acid succinate, azelaic acid, sebacic acid, Examples thereof include maleic acid, fumaric acid, glutaric acid, hexachloroheptanedicarboxylic acid, cyclohexanedicarboxylic acid, o-phthalic acid, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, tetrachlorophthalic acid and the like. In addition to these dicarboxylic acids, a small amount of an anhydride of polycarboxylic acid having three or more carboxyl groups, an adduct of unsaturated fatty acid, or the like can be used together.

Examples of the organic diol component include ethylene glycol, propylene glycol, butylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol and other alkylene glycols, and dimethylolcyclohexane. These may optionally be combined with small amounts of polyols such as trimethylolpropane, glycerin, pentaerythritol.

An amine compound containing the above primary amino group and / or secondary amino group, or a primary amino group and / or
Or as the amine compound (iv) having both a secondary amino group and a hydroxyl group, for example, alkylamines such as butylenediamine, hexamethylenediamine, tetraethylenepentamine, pentaethylenehexamine; monoethanolamine, diethanolamine, triethanol. Amine, mono (2-hydroxypropyl) amine, di (2-
Alkanolamines such as hydroxypropyl) amine; alicyclic polyamines such as 1,3-bisaminomethylcyclohexanone and isophoronediamine; aromatic polyamines such as xylylenediamine, metaxylenediamine, diaminodiphenylmethane, and phenylenediamine; ethylenediamine , Alkylenediamines such as propylenediamine, diethylenetriamine, and triethylenetetramine; and further amine compounds such as piperazine and polyamines derived from these, amine adducts with polyamides, polyamidoamines and epoxy compounds, ketimines, aldimines, etc. Can be mentioned.

Of the compounds (a) containing a plurality of active hydrogen groups described above, the compounds (i), (ii) and (iv) above, particularly ethylene glycol, propylene glycol and 1,4-butane. Diol, 1,6-hexanediol, diethylene glycol, hydrogenated bisphenol A,
Glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, dipentaerythritol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, poly (ethylene
Propylene) glycol, bisphenol A ethylene glycol ether, bisphenol A polypropylene glycol ether, butylene diamine, hexamethylene diamine, monoethanol amine, diethanol amine, triethanol amine, isophorone diamine, ethylene diamine, propylene diamine, diethylene triamine and triethylene tetramine. Those selected are preferred.

On the other hand, examples of caprolactone (b) that can be added to these active hydrogen compounds include γ-caprolactone, ε-caprolactone, δ-caprolactone and the like, and ε-caprolactone is particularly preferable.

The addition reaction of the above-mentioned active hydrogen-compound and caprolactone can be carried out by a method known per se. Specifically, for example, titanium compounds such as tetrabutoxytitanium and tetrapropoxytitanium, organotin compounds such as tin octylate, dibutyltin oxide and dibutyltin laurate, and the presence of catalysts such as metal compounds such as stannous chloride. Below, the active hydrogen-compound and caprolactone are about 100-
It can be carried out by heating at a temperature of about 250 ° C. for about 1 to about 15 hours.

The above catalysts are generally 0.5 to 1,000, based on the total amount of active hydrogen compound and caprolactone.
It can be used in ppm amounts. In addition, caprolactone is generally 1 to 30 mol, preferably 1 to 20 mol, and more preferably 1 to 1 per active hydrogen group-equivalent active hydrogen group of the compound (that is, per active hydrogen).
It can be used within a range of 5 mol.

The polyol compound (b-
3) is high plasticizing performance based on active hydrogen-compound,
It has both high compatibility with epoxy resins based on (poly) caprolactone and high reactivity with terminal hydroxyl groups, and is extremely useful as an internal plasticizer for epoxy resins for paints.

The polyol compound (b-3) is generally
The units derived from caprolactone may be contained in a total amount of 20 to 95% by weight, preferably 25 to 90% by weight, and generally 300 to 10,000, preferably 400 to 5,000. Can have a number average molecular weight of

The polyol-modified amino group-containing epoxy resin used as the component (B) in the resin composition of the present invention is obtained by adding the amino group-containing compound (b-2) and caprolactone to the epoxy resin (b-1). It can be produced by subjecting the polyol compound (b-3) having a terminal hydroxyl group of (3) to an addition reaction by a method known per se. The reaction of the amino group-containing compound (b-2) and the polyol compound (b-3) with respect to the epoxy resin (b-1) can be carried out in any order, but generally with respect to the epoxy resin (b-1). And an amino group-containing compound (b-
It is preferable to react 2) and the polyol compound (b-3) at the same time. Further, it is preferable that one end of the polyol compound (b-2) is added to the skeleton of the epoxy resin (b-1).

The above addition reaction is usually carried out in a suitable solvent at about 90 to about 170 ° C., preferably about 100 to about 15.
It can be performed at a temperature of 0 ° C. for about 1 to 5 hours, preferably about 2 to 4 hours. Examples of the solvent include hydrocarbons such as toluene, xylene, cyclohexane and n-hexane; ester systems such as methyl acetate, ethyl acetate and butyl acetate; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and methyl amyl ketone. Examples include amides such as dimethylformamide and dimethylacetamide; alcohols such as methanol, ethanol, n-propanol, and iso-propanol; and mixtures thereof.

The use ratio of each reaction component in the above addition reaction is not strictly limited and can be appropriately changed according to the application of the resin composition, but the epoxy resin (b-1), amino The following range is suitable based on the total solid content weight of the three components of the group-containing compound (b-2) and the polyol compound (b-2). Epoxy resin (b-1): generally 60 to 90% by weight,
Preferably 62-85% by weight, more preferably 62-85%
80% by weight, amino group-containing compound (b-2): generally 5 to 25% by weight, preferably 6 to 19% by weight, more preferably 6 to
18 wt%, polyol compound (b-3): generally 5 to 30 wt%, preferably 5 to 20 wt%, more preferably 5 to
18% by weight. Blocked polyisocyanate curing agent (C) The blocked polyisocyanate curing agent used as the component (C) in the cationic resin composition of the present invention is
It is an addition reaction product of a polyisocyanate compound and an isocyanate blocking agent in an approximately stoichiometric amount. Examples of the polyisocyanate compound used here include aromatic compounds such as tolylene diisocyanate, xylylene diisocyanate, phenylene diisocyanate, bis (isocyanatomethyl) cyclohexane, tetramethylene diisocyanate, hexamethylene diisocyanate, methylene diisocyanate, and isophorone diisocyanate, and fat. Group or alicyclic polyisocyanate compounds, and terminal isocyanates obtained by reacting excess amounts of these isocyanate compounds with low molecular weight active hydrogen-containing compounds such as ethylene glycol, propylene glycol, trimethylolpropane, hexanetriol, and castor oil. Examples of the compound include:

On the other hand, the isocyanate blocking agent is
The polyisocyanate compound is blocked by being added to the isocyanate group of the polyisocyanate compound, and the blocked polyisocyanate compound produced by the addition is stable at room temperature, but the baking temperature of the coating film (usually about 100 to about 2).
It is desirable that the blocking agent be capable of dissociating and regenerating free isocyanate groups when heated to (00 ° C.). Examples of the blocking agent satisfying such requirements include lactam compounds such as ε-caprolactam and γ-butyrolactam; oxime compounds such as methylethylketoxime and cyclohexanone oxime; phenolic compounds such as phenol, para-t-butylphenol and cresol. Examples thereof include compounds; aliphatic alcohols such as n-butanol and 2-ethylhexanol; aromatic alkyl alcohols such as phenylcarbinol and methylphenylcarbinol; ether alcohol compounds such as ethylene glycol monobutyl ether. Cationic Resin Composition The cationic resin composition provided by the present invention comprises the amino group-containing epoxy resin (A), the polyol-modified amino group-containing epoxy resin (B) and the blocked polyisocyanate curing agent (C) described above. ) Is contained in the resin composition of the present invention, the above components are present in the following proportions based on the total solid content of the components (A), (B) and (C). can do.

Component (A): 40 to 70% by weight, preferably 43 to 67% by weight, more preferably 45 to 65% by weight Component (B): 5 to 40% by weight, preferably 7 to 37% by weight, further 8 to 35% by weight Component (C): 10 to 40% by weight, preferably 15 to 40%
%, More preferably 17-35% by weight.

The cationic resin composition of the present invention is prepared by thoroughly mixing, for example, an amino group-containing epoxy resin (A), a polyol-modified amino group-containing epoxy resin (B) and a blocked polyisocyanate curing agent (C). ,Normal,
Prepared by neutralizing with an acidic neutralizing agent selected from formic acid, acetic acid, lactic acid, propionic acid, citric acid, malic acid, sulfamic acid, etc. in an aqueous medium, and water-solubilizing or water-dispersing the above components. Thus, a resin composition suitable as an emulsion for cationic electrodeposition coating composition can be obtained. As the neutralizing agent, acetic acid, formic acid or a mixture thereof is particularly suitable, and by using these acids, the finish of the coating composition to be formed, throwing power, low temperature curability, and stability of the coating are improved. To do.

When used as a paint, the resin composition of the present invention may contain a bismuth compound as a rust preventive agent. The type of bismuth compound that can be blended is not particularly limited, and examples thereof include inorganic bismuth compounds such as bismuth oxide, bismuth hydroxide, basic bismuth carbonate, bismuth nitrate and bismuth silicate. Of these, bismuth hydroxide is particularly preferable.

As the bismuth compound, an organic acid bismuth salt which is produced by reacting two or more kinds of organic acids with the bismuth compound as described above, and at least one kind of the organic acid is an aliphatic hydroxycarboxylic acid is used. It can also be used. Examples of the organic acid that can be used in the production of the organic acid bismuth salt include, for example, glycolic acid, glyceric acid, lactic acid, dimethylolpropionic acid, dimethylolbutyric acid, dimethylolvaleric acid, tartaric acid, malic acid, hydroxymalonic acid, dihydroxysuccinic acid, Examples thereof include trihydroxysuccinic acid, methylmalonic acid, benzoic acid and citric acid.

The above-mentioned inorganic bismuth compound and organic acid bismuth salt can be used alone or in combination of two or more kinds.

The content of these bismuth compounds in the resin composition of the present invention is not strictly limited,
Although it can be varied over a wide range according to the performance required for the resin composition, it is usually 0.01 to 10% by weight, preferably 0 based on the resin solid content in the resin composition of the present invention. A range of 0.05 to 5% by weight is suitable.

The cationic coating composition of the present invention may optionally further contain a tin compound as a curing catalyst. Examples of the tin compound include organic tin compounds such as dibutyl tin oxide and dioctyl tin oxide; dibutyl tin dilaurate, dioctyl tin dilaurate, dibutyl tin diacetate, dioctyl tin benzoate oxy, dibutyl tin benzoate oxy, dioctyl tin dibenzoate, dibutyl. Examples thereof include dialkyltin aliphatic or aromatic carboxylic acid salts such as tin dibenzoate, and among these, dialkyltin aromatic carboxylic acid salts and the like are preferable from the viewpoint of low temperature curability.

The content of these tin compounds in the resin composition of the present invention is not strictly defined and can be varied over a wide range depending on the performance required for the resin composition. Usually, the tin content is 0.01 to 8 parts by weight per 100 parts by weight of the resin solid content in the paint,
It is preferable that the amount be in the range of 0.05 to 5 parts by weight.

If desired, the cationic resin composition of the present invention may further contain coating additives such as color pigments, extender pigments, rust preventive pigments, organic solvents, pigment dispersants and surface conditioners. it can.

The cationic resin composition of the present invention can be coated on a desired substrate surface by cationic electrodeposition coating. Electrodeposition coating generally has a solid concentration of about 5 to about 4
An electrodeposition bath comprising the resin composition of the present invention, which is diluted with deionized water or the like so as to be 0% by weight, preferably 15 to 25% by weight, and whose pH is adjusted within the range of 5.5 to 9, Normally, the bath temperature is adjusted to about 15 to about 35 ° C, and the load voltage is 100 to
It can be performed under the condition of 400V.

The film thickness of the electrodeposition coating film formed using the resin composition of the present invention is not particularly limited, but generally 10 to 40 μm, particularly 15 based on the cured coating film.
It is preferably within the range of to 35 μm. Further, the baking temperature of the coating film is generally about 120 to about 200 ° C., preferably about 140 to about 180 ° C. on the surface of the article to be coated, and the baking time is about 5 to 60 minutes, preferably Is 10
It can be about 30 minutes.

The cationic resin composition of the present invention is preferably used as a cationic electrodeposition coating, but is not limited thereto, and it is used as a solvent-based coating for protecting steel sheets for coating by methods such as electrostatic coating and roll coating. It can also be used as an edible primer.

Further, the resin composition of the present invention can be used as a two-pack type constantly dry paint or adhesive by using a polyisocyanate compound or a melamine resin instead of the blocked polyisocyanate curing agent as a crosslinking agent. You can also

The cationic resin composition of the present invention forms a cured coating film excellent in corrosion resistance, suitability for electrodeposition coating on a rust-preventing steel plate, and excellent in adhesion to a base material. It is useful as an undercoat paint for automobile parts, construction / construction fields, etc.

Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the embodiments. In addition, "part" and "%" show "weight part" and "weight%", respectively. Production Example 1. Amino group-containing epoxy resin Epicoat 828EL (manufactured by Japan Epoxy Resins,
Trade name, epoxy resin, epoxy equivalent 190, molecular weight 3
50) 1010 g, bisphenol A 390 g and dimethylbenzylamine 0.2 g were added and reacted at 130 ° C. until the epoxy equivalent became 800. Next, 160 g of diethanolamine and 65 g of a ketimine compound of diethylenetriamine were added and reacted at 120 ° C. for 4 hours, 355 g of butyl cellosolve was added, an amine value of 67 and a solid content of 80%.
Amino group-containing epoxy resin No. 1 was obtained. Production example 2. 300 g of ε-caprolactone was added to 400 g of polyol-modified amino group-containing epoxy resin PP-400 (manufactured by Sanyo Kasei Co., Ltd., trade name, polypropylene glycol, molecular weight 400), and the temperature was raised to 130 ° C. After that, 0.01 g of tetrabutoxytitanium was added to 170 ° C.
The temperature was raised to. While keeping this temperature, sampling was performed over time, the amount of unreacted ε-caprolactone was traced by infrared absorption spectrum measurement, and the reaction mixture was cooled when the reaction rate reached 98% or more to obtain a denaturant 1.

Next, in another flask, Epicoat 828
EL (Japan Epoxy Resin Co., Ltd., trade name, epoxy resin, epoxy equivalent 190, molecular weight 350) 1010
g, 390 g of bisphenol A and 0.2 g of dimethylbenzylamine were added, and the mixture was reacted at 130 ° C. until the epoxy equivalent became 800. Next, 200 g of modifier 1, 140 g of diethanolamine and 65 g of a diethylenetriamine ketimine compound were added and reacted at 120 ° C. for 4 hours, and then 300 g of butyl cellosolve was added to give an amine value of 3
1, a polyol-modified amino group-containing epoxy resin No. 2 having a resin solid content of 90% was obtained. Production example 3. In place of the modifier 1 in Production Example 2 of polyol-modified amino group-containing epoxy resin, praxel 20 was used.
Production Example 2 except that 1561 g of 8 (trade name, polycaprolactone polyol compound manufactured by Daicel Chemical Industries, Ltd.) was used.
In the same manner as described above, a polyol-modified amino group-containing epoxy resin No. 90 having a solid content of 90% was used. Got 3. Production Example 4. Blocked polyisocyanate curing agent 174 g of hexamethylene isocyanate and 38 g of methyl isobutyl ketone were slowly added dropwise with 174 g of methyl ethyl ketone oxime at 50 ° C to obtain a blocked polyisocyanate curing agent a having a solid content of 90%. Production Example 5. Blocked polyisocyanate curing agent M-200 (Mitsui Chemicals, trade name, Crude MDI) 2
To 70g, add 46g of methyl isobutyl ketone and 70 ℃
The temperature was raised to. After 281 g of diethylene glycol monoethyl ether was slowly added, the temperature was raised to 90 ° C. While keeping this temperature, sampling was performed with the passage of time, and it was confirmed by infrared absorption spectrum measurement that unreacted isocyanate was no longer absorbed, whereby a blocked polyisocyanate curing agent (b) having a solid content of 90% was obtained. It was Production Example 6. Amino group-containing epoxy resin No. 1 obtained in Production Example 1 for emulsion for cationic electrodeposition coating. 1 6
2.5 parts of the polyol-modified amino group-containing epoxy resin No. obtained in Production Example 2 2 22.2 parts, 33.3 parts of the blocked polyisocyanate curing agent a (methyl ethyl ketone oxime blocked product of hexamethylene isocyanate) obtained in Production Example 4, LSN-105 (manufactured by Mitsui Organic Synthesis Co., Ltd., trade name, dibutyl tin di) Benzoate, solid content 40
%) 2.5 parts and 10% formic acid 8.2 parts were mixed and stirred uniformly, and then 201.8 parts of deionized water was added dropwise over about 15 minutes while stirring vigorously to obtain a solid content of 30.0%. To obtain Emulsion I for cationic electrodeposition coating. Production Example 7. Emulsion for Cationic Electrodeposition Paint In Production Example 6, the cationic polyelectrolyte composition was prepared in the same manner except that the blocked polyisocyanate curing agent b obtained in Production Example 5 was used instead of the blocked polyisocyanate curing agent a. An emulsion II for paint was obtained. Production Example 8. In Production Example 6 of emulsion for cationic electrodeposition coating composition, polyol-modified amino group-containing epoxy resin No. Instead of 2, the polyol-modified amino group-containing epoxy resin No. 1 obtained in Production Example 3 was used. Except using 3.
Emulsion III for cationic electrodeposition coating was obtained with the same amount and operation. Production Example 9. Emulsion for cationic electrodeposition paint Amino group-containing epoxy resin No. 1 87.5 parts, blocked polyisocyanate curing agent a (methyl ethyl ketone oxime blocked product of hexamethylene isocyanate) 33.3 parts, LSN-105 (manufactured by Mitsui Organic Synthesis Co.,
(Product name, dibutyltin dibenzoate, solid content 40%)
After mixing 2.5 parts and 8.2 parts of 10% formic acid and stirring uniformly, 201.8 parts of deionized water was added dropwise over about 15 minutes with strong stirring to obtain a cation having a solid content of 30.0%. Emulsion IV for electrodeposition paint was obtained. Production Example 10. In Production Example 9 of emulsion for cationic electrodeposition coating, Sanix PP-1000 was further added.
Emulsion V for cationic electrodeposition coating composition was obtained by the same blending amount and operation except that 10 parts of (trade name, polyether polyol manufactured by Sanyo Kasei Co., Ltd.) was added. Production Example 11. Pigment dispersion paste 60% quaternary ammonium salt type epoxy resin 5.83
Parts, titanium white 14.5 parts, carbon black 0.4 parts, extender pigment 7.0 parts and bismuth hydroxide 2.0 parts, deionized water 2.24 parts is added, and the solid content is 55.0%. A dispersion paste was obtained. Examples and Comparative Examples Example 1 To 297 parts of emulsion I for cationic electrodeposition coating, 49.8 parts of pigment dispersion paste and 235.7 parts of deionized water were added to obtain a cationic electrodeposition coating composition having a solid content of 20%. It was Examples 2 and 3 and Comparative Examples 1 and 2 In the same manner as in Example 1, pigment dispersion pastes and deionized water were added to each of the cationic electrodeposition coating emulsions II to V at the compounding ratios shown in Table 1 below to give solids. A cationic electrodeposition coating composition having a content of 20% was obtained.

[0052]

[Table 1]

Coating test In each of the cationic electrodeposition coatings obtained in the above Examples and Comparative Examples,
0.8 × 15 chemical conversion treated with Palbond # 3020 (trade name, zinc phosphate treatment agent manufactured by Nippon Parkerizing Co., Ltd.)
A 0 × 70 mm galvanized steel sheet was dipped, and electrodeposition coating was performed using this as a cathode (coating voltage of anti-rust steel sheet: 27
0V). The formed electrodeposition coating film was baked at 170 ° C. for 20 minutes using an electrodeposition hot air dryer. The performance test results of the obtained coated plate are shown in Table 2 below.

[0054]

[Table 2]

The performance test was carried out according to the following method. (Note 1) Corrosion-proof steel plate electrodeposition suitability : A galvanized steel plate is immersed as the cathode of the electrodeposition bath, and the voltage is 270 V and the bath temperature is 28
Count the number of pinholes in the test piece 10 × 10 cm when coated at ℃. ◯ indicates that no pinholes were generated, Δ indicates that 3 to 5 occurred, and x indicates that 10 or more occurred. (Note 2) Anticorrosion property : Each electrodeposition coated plate obtained by baking for 20 minutes at a temperature of 170 ° C. was cross-cut with a knife into the electrodeposition coating film to reach the substrate,
According to SZ-2371, a salt water spray resistance test was performed for 840 hours, and the rust from a knife scratch and the blister width were evaluated according to the following criteria. ○ indicates that the maximum width of rust and blisters is 2 from the cut
Less than mm (one side); △ indicates that the maximum width of rust and blisters is 2 mm or more and less than 3 mm from the cut portion (one side) and blisters are observed on the entire coated surface; × indicates the maximum width of rust and blisters. It shows that blisters are observed on the entire coated surface 3 mm or more from the cut portion. (Note 3) Impact resistance (Dupont type) : 2 at a temperature of 170 ° C
The test plate obtained by baking for 0 minutes was heated at a temperature of 2
After placing it in a constant temperature and humidity room at 0 ± 1 ° C and a humidity of 75 ± 2% for 24 hours, attach a pedestal and a shooting core of a specified size to the DuPont impact tester, and turn the coated surface of the test plate upward. It was sandwiched between them, and then a weight weighing 500 g was dropped on the shooting core, and the maximum height at which there was no crack or peeling of the coating film due to impact was measured. (Note 4) Secondary adhesion : TP-37 gray (manufactured by Kansai Paint Co., Ltd., trade name, aminoalkyd-based intermediate coating) and Neoamilac 6000 (Kansai Paint Co., Ltd.) on the coated surface of the coated plate obtained in the coating test. Product, product name, amino alkyd-based top coating) are sequentially applied, and the baked and hardened coated plate is immersed in 40 ° C. hot water for 240 hours, and a 2 mm square edge cut is inserted, and then a cellotape (registered trademark) peel test Then, the residual ratio (remaining number / 100) of the coating film is evaluated. ○: 100/100, △: 90 to 99/10
0 and 89 indicate 89 or less / 100, respectively. (Note 5) Flex resistance : test plate temperature 20 ± 1 ° C, humidity 7
After placing in a constant temperature and humidity room of 5 ± 2% for 24 hours, 1-2
Bend 180 ° in seconds. When there was no abnormality on both the front and back sides of the bent portion, it was evaluated as ◯, and when at least one of them had an abnormality such as crack or peeling, it was evaluated as x. (Note 6) The curable: the coating surface of each electrodeposition coated plate obtained by baking at a temperature 170 ° C. 20 min, gauze of 4 plies impregnated with acetone, pressure 0.392MPa
The appearance of the coated surface after rubbing about 3 to 4 cm in length (about 4 kgf / cm ² ) for about 20 reciprocations was visually evaluated according to the following criteria. O indicates that no scratch is observed on the coated surface; Δ indicates that the coated surface is scratched but no base is visible; X indicates that the coating film is dissolved and the base is visible.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akira Tominaga 4-17-1, Higashi-Hachiman, Hiratsuka-shi, Kanagawa Kansai Paint Co., Ltd. (56) References JP-A 64-85262 (JP, A) (58) Survey Areas (Int.Cl. ⁷ , DB name) C08G 18/00-18/87 C09D 5/44 C09D 163/00-163/10 C09D 175/00-175/16

Claims (24)

(57) [Claims] 1. The following components: (A) Amino group-containing epoxy resin obtained by adding an amino group-containing compound (a-2) to an epoxy resin (a-1) having an epoxy equivalent of 400 to 3000, (B). Reaction of an epoxy resin (b-1) having an epoxy equivalent of 180 to 2500 with an amino group-containing compound (b-2) and a polyol compound (b-3) obtained by adding caprolactone to a compound having a plurality of active hydrogen groups. Comprising a polyol-modified amino group-containing epoxy resin thus obtained, and (C) a blocked polyisocyanate curing agent,
Containing 40 to 70% by weight of component (A), 5 to 40% by weight of component (B), and 10 to 40% by weight of component (C) based on the total solid content of (B) and (C). A cationic resin composition comprising: 2. The composition according to claim 1, wherein the epoxy resin (a-1) is obtained by reacting a polyphenol compound with epihalohydrin. 3. The composition according to claim 2, wherein the polyphenol compound is bisphenol A. 4. The epoxy resin (a-1) is 450 to 25.
The composition according to any one of claims 1 to 3, which has an epoxy equivalent in the range of 00. 5. The amino group-containing epoxy resin (A) is obtained by adding the amino group-containing compound (a-2) to the epoxy resin (a-1).
In the weight ratio (a-1) / (a-2) of 90 / 10-6
The composition according to any one of claims 1 to 4, which is obtained by adding within the range of 0/40. 6. The amino group-containing epoxy resin (A) is 40
A polymer having an amine value within the range of -80.
6. The composition according to any one of to 5. 7. The composition according to claim 1, wherein the epoxy resin (b-1) is obtained by reacting a polyphenol compound with epihalohydrin. 8. The composition according to claim 7, wherein the polyphenol compound is bisphenol A. 9. The epoxy resin (b-1) is 200 to 20.
The composition according to any one of claims 1 to 8, which has an epoxy equivalent in the range of 00. 10. The active hydrogen group in the compound containing a plurality of active hydrogen groups is selected from the group consisting of an alcoholic hydroxyl group, a primary amino group and a secondary amino group.
The composition according to any one of 1 to 9. 11. A compound having a plurality of active hydrogen groups is a low molecular weight polyol, a linear or branched polyether polyol, a linear or branched polyester polyol, a primary and / or secondary amino group. The composition according to any one of claims 1 to 10, which is selected from the group consisting of an amine compound containing OH, and a hydroxyamine compound having both a primary and / or secondary amino group and a hydroxyl group. 12. The composition according to claim 1, wherein the compound containing a plurality of active hydrogen groups has a number average molecular weight within the range of 62 to 5,000. 13. The composition according to claim 1, wherein the compound containing a plurality of active hydrogen groups contains an average of at least 2 to less than 30 active hydrogen groups per molecule. object. 14. A compound having a plurality of active hydrogen groups is ethylene glycol, propylene glycol, 1,
4-butanediol, 1,6-hexanediol, diethylene glycol, hydrogenated bisphenol A, glycerin, trimethylolethane, trimethylolpropane,
Pentaerythritol, dipentaerythritol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, poly (ethylene / propylene) glycol, bisphenol A ethylene glycol ether, bisphenol A polypropylene glycol ether, butylene diamine, hexamethylene diamine, monoethanol amine, diethanol amine The composition according to claim 1, which is selected from the group consisting of, triethanolamine, isophoronediamine, ethylenediamine, propylenediamine, diethylenetriamine and triethylenetetramine. 15. The composition according to claim 1, wherein the caprolactone is ε-caprolactone. 16. The molar amount of caprolactone added to the compound containing a plurality of active hydrogen groups is such that
It is in the range of 1 to 30 mol per equivalent.
The composition according to any one of 1. 17. A polyol-modified amino group-containing epoxy resin (B) is obtained by simultaneously reacting an epoxy resin (b-1) with an amino group-containing compound (b-2) and a polyol compound (b-3). The composition according to any one of claims 1 to 16, which is obtained. 18. The polyol-modified amino group-containing epoxy resin (B) is based on the total solid content weight of the epoxy resin (b-1), the amino group-containing compound (b-2) and the polyol compound (b-3). 60 to 90% by weight of the epoxy resin (b-1) and 5 of the amino group-containing compound (b-2).
˜25 wt% and polyol compound (b-3) 5 to 3
The reaction is carried out at a ratio of 0% by weight.
18. The composition according to any one of 17. 19. The polyol-modified amino group-containing epoxy resin (B) is based on the total solid weight of the epoxy resin (b-1), the amino group-containing compound (b-2) and the polyol compound (b-3). 62 to 85% by weight of the epoxy resin (b-1) and 6 of the amino group-containing compound (b-2).
-19% by weight and 5-2 of the polyol compound (b-3)
The reaction is carried out at a ratio of 0% by weight.
19. The composition according to any of 18. 20. 43 to 67% by weight of component (A), based on the total solid content of components (A), (B) and (C),
7-37% by weight of component (B) and 15% of component (C)
20 to 40% by weight of the composition according to any one of claims 1 to 19. 21. The composition according to claim 1, further containing a bismuth compound as a rust preventive agent. 22. A cationic electrodeposition bath comprising the cationic resin composition according to claim 1. 23. A cationic electrodeposition coating method, which comprises using the cationic resin composition according to any one of claims 1 to 21. 24. An article coated with the cationic resin composition according to any one of claims 1 to 21.