JP5563436B2 - Cationic electrodeposition coating composition - Google Patents

Description

  The present invention relates to a cationic electrodeposition coating composition that is excellent in finish, chipping resistance, and warm salt water immersion.

Cationic electrodeposition paints have been widely used as undercoat paints for metal products such as automobile bodies because they have excellent paint workability and good corrosion resistance. Recently, in the automotive industry field, there has been an increasing demand for durability improvement in corrosive environments of car body skins (for example, salt dispersion on roads in cold regions). Instead, a galvanized steel sheet having excellent rust prevention properties is used. On the other hand, there is a problem that the coating film applied to the outer plate of the vehicle body causes a so-called “chipping” in which rock salt particles, pebbles and the like which are lifted during running collide with the coating film surface and the coating film peels off.

Especially in low-temperature environments such as in cold regions, the coating film becomes hard and loses elasticity, so the collision can hardly be alleviated, and impact is directly applied to the steel sheet, between the steel sheet and the chemical conversion coating on the surface, There is an urgent need to examine chipping countermeasures in a low-temperature environment because peeling easily occurs between galvanized layers.
As a countermeasure, for example, a cationic electrodeposition coating composition containing an amine-epoxy resin adduct and a urethane resin adduct has been disclosed as a film having flexibility, impact resistance, etc. (Patent) Reference 1). However, even if what is specifically disclosed as a urethane resin adduct to be blended in this coating composition is simply blended in the cationic electrodeposition coating composition, it is not compatible with both chipping resistance and warm salt water soaking resistance. It was enough.

  In addition, a high molecular weight polyurethane having a number average molecular weight of at least 15,000, which is compatible with the electrodeposition resin, is added to the coating film for improving chipping resistance and rust prevention. There is a cationic electrodeposition coating composition as described below (Patent Document 2). However, since the polyurethane has a high molecular weight, there are problems that water dispersion stability, paint stability when blended in a cationic electrodeposition paint, finish, hot salt water soaking resistance, and the like are lowered.

In addition, an electrodeposition coating composition comprising a particle A containing a resin a having a solubility parameter of δa, a resin b having a solubility parameter of δb, and a particle B containing a curing agent, wherein (δ _b −δ _a ) The value of 1) is 1 or more, the dynamic glass transition temperature of the particle A is −110 to 10 ° C., the dynamic glass transition temperature of the particle B is 60 to 150 ° C., and the film is formed only from the particle A. For the purpose of improving chipping resistance with an elongation percentage of the film being 200% or more, a coating film excellent in corrosion resistance and chipping resistance is obtained by separating the particles A and B in the electrodeposition coating film. An invention is disclosed (Patent Document 3).
However, since the two kinds of incompatible particles are contained, there is a problem that the finishability is lowered and the hot salt water immersion property is lowered.

  Further, an amino group-containing epoxy resin (A) obtained by adding an amino group-containing compound (a-2) to an epoxy resin (a-1) having an epoxy equivalent of 400 to 3000, an epoxy resin (b) having an epoxy equivalent of 180 to 2500 A polyol-modified amino group-containing epoxy resin obtained by reacting a polyol compound (b-3) obtained by adding caprolactone to an amino group-containing compound (b-2) and a compound containing a plurality of active hydrogen groups to -1) (B), and the blocked polyisocyanate curing agent (C), and based on the total solid content of the components (A), (B) and (C), the component (A) is 40 to 70% by weight, A cationic resin composition excellent in anticorrosive properties containing 5 to 40% by weight of component (B) and 10 to 40% by weight of component (C) is disclosed (Patent Document 4). However, finish and chipping resistance were insufficient. From such a background, there has been a demand for a cationic electrodeposition coating composition that is excellent in finish, chipping resistance, and warm salt water immersion.

JP 63-89578 A Japanese Patent Laid-Open No. 7-150079 JP 2002-129105 A JP 2002-60454 A

  The problem to be solved by the invention is to provide a cationic electrodeposition coating composition that is excellent in finish, chipping resistance, and warm salt water immersion.

  As a result of intensive studies to solve the above problems, the inventors have found that the above problems can be solved by the cationic electrodeposition coating composition containing the polyol-modified amino group-containing epoxy resin (A). It came to complete.

That is, the present invention
1. Polyol compound (a2) obtained by adding caprolactone to a compound having a plurality of active hydrogen groups to a modified epoxy resin (a1) obtained by adding caprolactone to a hydroxyl group-containing epoxy resin having an epoxy equivalent of 180 to 2500 And a cationic electrodeposition coating composition containing a polyol-modified amino group-containing epoxy resin (A) obtained by reacting an amino group-containing compound (a3),
2. The cationic electrodeposition coating composition according to 1, wherein the active hydrogen group in the compound having 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,
3. The cationic electrodeposition coating composition according to item 1 or 2, which contains a blocked polyisocyanate compound,
The present invention relates to an article coated with the cationic electrodeposition coating composition according to any one of 4.1 to 3.

  With the cationic electrodeposition coating composition of the present invention, a coated article having excellent finish, chipping resistance, and warm salt water immersion resistance can be obtained. Since the coating film made of the cationic electrodeposition coating composition does not peel off against rock splashes and can suppress corrosion, the strength reduction of the automobile body can be suppressed and improvement in safety can be achieved.

The present invention is obtained by adding caprolactone to a compound containing a plurality of active hydrogen groups to a modified epoxy resin (a1) obtained by adding caprolactone to a hydroxyl group-containing epoxy resin having an epoxy equivalent of 180 to 2,500. It is a cationic electrodeposition coating composition containing a polyol-modified amino group-containing epoxy resin (A) obtained by reacting a polyol compound (a2) and an amino group-containing compound (a3). Details will be described below.
[Polyol-modified amino group-containing epoxy resin (A)]
The modified epoxy resin (a1) is obtained by adding caprolactone to a hydroxyl group-containing epoxy resin having an epoxy equivalent of 180 to 2,500.

Hydroxyl group-containing epoxy resin The hydroxyl group-containing epoxy resin is a compound having at least two hydroxyl groups and two epoxy groups in one molecule, and is 180 to 2,500, preferably 200 to 2,000, more preferably 400. Suitable are those having an epoxy equivalent weight in the range of ˜1,500 and having a number average molecular weight in the range of at least 350, in particular 400 to 4,000, more particularly 800 to 2,000, in particular Those obtained by the reaction of a polyphenol compound and epihalohydrin are preferred.

  Here, the “number average molecular weight” is a separation column of “TSK GEL4000HXL”, “TSK GEL3000HXL”, “TSK GEL2500HXL”, “TSK GEL2000HXL” (manufactured by Tosoh Corporation) according to the method described in JIS K 0124-83. Four samples were obtained from a chromatogram obtained with an RI refractometer and a standard polystyrene calibration curve at 40 ° C. and a flow rate of 1.0 ml / min using tetrahydrofuran for GPC as an eluent.

  Examples of the polyphenol compound used for forming the epoxy resin include bis (4-hydroxyphenyl) -2,2-propane [bisphenol A], bis (4-hydroxyphenyl) methane [bisphenol F], bis ( 4-hydroxycyclohexyl) methane [hydrogenated bisphenol F], 2,2-bis (4-hydroxycyclohexyl) propane [hydrogenated bisphenol A], 4,4′-dihydroxybenzophenone, bis (4-hydroxyphenyl) -1, 1-ethane, bis (4-hydroxyphenyl) -1,1-isobutane, bis (4-hydroxy-2 or 3-tert-butyl-phenyl) -2,2-propane, bis (2-hydroxynaphthyl) methane, Tetra (4-hydroxyphenyl) -1,1,2,2-ethane 4,4'-dihydroxydiphenyl sulfone, phenol novolak, and the like cresol novolak.

  Moreover, as an epoxy resin obtained by reaction of a polyphenol compound and epichlorohydrin, especially following formula (1) induced | guided | derived from bisphenol A is mentioned.

In the formula (1), those represented by n = 1 to 5 are preferable.

  Examples of such commercially available epoxy resins include those sold by Japan Epoxy Resins Co., Ltd. under the trade names jER828EL, jER1001, jER1002, jER1004, and jER1007.

Caprolactone Examples of caprolactone include [gamma] -caprolactone, [epsilon] -caprolactone, [delta] -caprolactone, lactone, valerolactone and the like, and [epsilon] -caprolactone is particularly preferable.

Modified epoxy resin (a1)
The addition reaction of the hydroxyl group-containing epoxy resin and caprolactone can be carried out by a method known per se. Specifically, caprolactone is generally in the range of 1 to 15 mol, preferably 1 to 10 mol, more preferably 1 to 7 mol per 1 equivalent of hydroxyl group of the hydroxyl group-containing epoxy resin, for example, tetrabutoxy titanium, tetra In the presence of a catalyst such as a titanium compound such as propoxy titanium, an organic tin compound such as tin octylate, dibutyltin oxide and dibutyltin laurate; and a metal compound such as stannous chloride, a hydroxyl group-containing epoxy resin and caprolactone are used in the presence of 100. The modified epoxy resin (a1) can be produced by heating at a temperature of ˜250 ° C. for about 1 to about 15 hours.
The obtained modified epoxy resin (a1) has a number average molecular weight in the range of 700 to 5,000, preferably 1,000 to 4,500. This modified epoxy resin (a1) is extremely useful for achieving both chipping resistance and warm salt water immersion resistance.

Polyol compound (a2)
The polyol compound (a2) is used for internal plasticization (modification) of the modified epoxy resin (a1), and is obtained by adding caprolactone to a compound containing a plurality of active hydrogen groups.

  The active hydrogen group means an atomic group containing at least one active hydrogen and includes, for example, alcoholic hydroxyl group, primary amino group, secondary amino group and the like. Thus, examples of the compound containing a plurality of such active hydrogen groups in one molecule include (i) low molecular weight polyol, (ii) linear or branched polyether polyol, and (iii) linear or branched. A polyester polyol of (iv), an amine compound containing a primary amino group and / or a secondary amino group, or a hydroxyamine compound having both a primary amino group and / or a secondary amino group and a hydroxyl group Etc. These compounds containing a plurality of active hydrogen groups can have a number average molecular weight in the range of 62 to 5,000, preferably 62 to 4,000, more preferably 62 to 1,500. In addition, the compound containing a plurality of active hydrogen groups preferably has an average of at least 2 and less than 30, particularly 2 to 10 active hydrogen groups per molecule.

  The low molecular weight polyol (i) is a compound having at least two alcoholic hydroxyl groups in one molecule. Specifically, for example, ethylene glycol, propylene glycol, 1,3-butylene glycol, 1,4 Diols such as butanediol, 1,6-hexanediol, diethylene glycol, dipropylene glycol, cyclohexane-1,4-dimethylol, neopentyl glycol, triethylene glycol, hydrogenated bisphenol A; glycerin, trimethylolethane, trimethylol Examples include triols such as propane; tetrols such as pentaerythritol and α-methylglycoside; hexols such as sorbitol and dipentaerythritol; octols such as sucrose.

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

  The linear or branched polyester polyol (iii) can usually have a number average molecular weight in the range of 200 to 10,000, preferably 200 to 3,000, specifically, an organic dicarboxylic acid. Or the thing obtained by the polycondensation reaction of the anhydride and organic diol on the conditions of excess organic diol is mentioned. Examples of the organic dicarboxylic acid used herein include aliphatic, alicyclic or aromatic dicarboxylic acids having 2 to 44 carbon atoms, particularly 4 to 36 carbon atoms such as succinic acid adipic acid, azelaic acid, sebacic acid, 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 polycarboxylic acid anhydrides or unsaturated fatty acid adducts having three or more carboxyl groups can be used in combination.

  Examples of the organic diol component include alkylene glycols such as ethylene glycol, propylene glycol, butylene glycol, 1,4-butanediol, 1,6-hexanediol, and neopentyl glycol, and dimethylolcyclohexane. In some cases, these may be used in combination with a small amount of a polyol such as trimethylolpropane, glycerin or pentaerythritol.

  Examples of the amine compound containing the primary amino group and / or the secondary amino group, or the amine compound (iv) having both the primary amino group and / or the secondary amino group and the hydroxyl group include butylene. Alkylamines such as diamine, hexamethylenediamine, tetraethylenepentamine and pentaethylenehexamine; alkanols such as monoethanolamine, diethanolamine, triethanolamine, mono (2-hydroxypropyl) amine and di (2-hydroxypropyl) amine Amines; Alicyclic polyamines such as 1,3-bisaminomethylcyclohexanone and isophoronediamine; Aromatic polyamines such as xylylenediamine, metaxylenediamine, diaminodiphenylmethane, and phenylenediamine; ethylenediamine, propylene diene Alkylene polyamines such as amine, diethylenetriamine and triethylenetetramine; and other amine compounds derived from piperazine and these polyamines such as amine adducts with polyamides, polyamidoamines and epoxy compounds, ketimines and aldimines Can do.

  Among the compounds containing a plurality of active hydrogen groups described above, the compounds (i), (ii) and (iv) above, particularly 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 polyethylene glycol Ether, bisphenol A polypropylene glycol ether, butylenediamine, hexamethylenediamine, monoethanolamine, diethanolamine, triethanolamine, isophoro Diamine, ethylenediamine, propylenediamine, those selected from the group consisting of diethylenetriamine and triethylenetetramine are preferred.

  On the other hand, as caprolactone that can be added to a compound containing a plurality of active hydrogen groups, the same caprolactone can be used, specifically, γ-caprolactone, ε-caprolactone, δ-caprolactone, etc. In particular, ε-caprolactone is preferred. The above addition reaction of a compound containing a plurality of active hydrogen groups and caprolactone can be carried out by a method known per se. Specifically, for example, titanium compounds such as tetrabutoxy titanium and tetrapropoxy titanium, organotin compounds such as tin octylate, dibutyltin oxide, and dibutyltin laurate; presence of a catalyst such as a metal compound such as stannous chloride Below, it can carry out by heating the compound containing a several active hydrogen group and caprolactone at the temperature of 100-250 degreeC for about 1 to about 15 hours.

  The catalyst can be used in an amount of 0.5 to 1,000 ppm based on the total amount of the compound having a plurality of active hydrogen groups and caprolactone. Caprolactone is generally 1 to 30 mol, preferably 1 to 20 mol, more preferably 1 to 15 mol per equivalent of active hydrogen group of a compound having a plurality of active hydrogen groups (that is, per active hydrogen). Can be used within the range.

  The polyol compound (a2) thus obtained has both high compatibility with the hydroxyl group-containing epoxy resin (a1) based on a compound having a plurality of active hydrogen groups, high plasticizing performance based on caprolactone, and high reactivity due to terminal hydroxyl groups. Therefore, it is useful for improving the chipping resistance and warm salt water immersion resistance of the obtained coating film.

  The polyol compound (a2) can generally contain a unit derived from caprolactone in a total amount of 20 to 95% by mass, preferably 25 to 90% by mass, and generally 300 to 10,000, preferably Can have a number average molecular weight in the range of 400 to 5,000.

Amino group-containing compound (a3)
In the present invention, in order to obtain the polyol-modified amino group-containing epoxy resin (A), the amino group-containing compound (a3) reacted with the modified epoxy resin (a1) and the polyol compound (a2) is a modified epoxy resin (a1). ) Which is a cationic component for cationizing the modified epoxy resin (a1) by introducing an amino group into the modified epoxy resin (a1) and containing at least one active hydrogen that reacts with the epoxy group.

  Examples of the amino group-containing compound (a3) used for such purpose include mono- or di-methyl monoamine such as monomethylamine, dimethylamine, monoethylamine, diethylamine, monoisopropylamine, diisopropylamine, monobutylamine and dibutylamine. -Alkylamine: Alkanolamines such as monoethanolamine, diethanolamine, mono (2-hydroxypropyl) amine, di (2-hydroxypropyl) amine, monomethylaminoethanol, monoethylaminoethanol; ethylenediamine, propylenediamine, butylenediamine, hexa Such as methylenediamine, tetraethylenepentamine, pentaethylenehexamine, diethylaminopropylamine, diethylenetriamine, triethylenetetramine Ruki polyamines and ketimine of these polyamines; ethyleneimine, alkylene imine such as propylene imine; piperazine, morpholine, and cyclic amines, such as pyrazine and the like. Of these amines, amines obtained by ketiminizing primary amines can also be used.

  The polyol-modified amino group-containing epoxy resin (A) used in the cationic electrodeposition coating composition of the present invention includes a polyol compound (a2) having a terminal hydroxyl group derived from caprolactone and an amino group in the modified epoxy resin (a1). It can be produced by subjecting the containing compound (a3) to an addition reaction by a method known per se.

  The reaction of the polyol compound (a2) and the amino group-containing compound (a3) with respect to the modified epoxy resin (a1) can be carried out in any order, but the polyol compound (a2) and amino group with respect to the modified epoxy resin (a1). It is preferable to react the group-containing compound (a3) simultaneously. Further, it is preferable that one end of the polyol compound (a2) is added to the skeleton of the modified epoxy resin (a1).

The above addition reaction can be usually performed in a suitable solvent at a temperature of about 90 to about 170 ° C., preferably about 100 to about 150 ° C. for 1 to 5 hours, preferably 2 to 4 hours.
Examples of the organic solvent include hydrocarbons such as toluene, xylene, cyclohexane, and n-hexane; esters such as methyl acetate, ethyl acetate, and butyl acetate; acetone, methyl ethyl ketone, methyl isobutyl ketone, and methyl amyl ketone. Examples include ketones; amides such as dimethylformamide and dimethylacetamide; alcohols such as methanol, ethanol, n-propanol, and iso-propanol; or a mixture thereof.

  The use ratio of each reaction component in the above addition reaction is not strictly limited, and can be appropriately changed depending on the use of the cationic electrodeposition coating composition, but the modified epoxy resin (a1), polyol compound The following ranges are suitable based on the total solid mass of the three components of (a2) and amino group-containing compound (a3).

  Modified epoxy resin (a1): 60 to 90% by mass, preferably 62 to 85% by mass, more preferably 62 to 80% by mass, polyol compound (a2): 5 to 30% by mass, preferably 5 to 20% by mass, More preferably, it is 5-18 mass%, amino group containing compound (a3): 5-25 mass%, Preferably it is 6-19 mass%, More preferably, it is 6-18 mass%. These ratios are useful for improving the finish, chipping resistance, and warm salt water soakability of the obtained coating film.

Blocked Polyisocyanate Curing Agent The polyol-modified amino group-containing epoxy resin (A) of the present invention can be used in combination with a blocked polyisocyanate curing agent. By using it in combination, a thermosetting cationic electrodeposition coating can be prepared.

  The above-mentioned blocked polyisocyanate curing agent is an addition reaction product of a polyisocyanate compound and an isocyanate blocking agent in an approximately chemical theoretical amount. As the polyisocyanate compound used in the blocked polyisocyanate curing agent, known compounds can be used. For example, tolylene diisocyanate, xylylene diisocyanate, phenylene diisocyanate, diphenylmethane-2,2'-diisocyanate, diphenylmethane- Aromatics such as 2,4′-diisocyanate, diphenylmethane-4,4′-diisocyanate, crude MDI [polymethylene polyphenyl isocyanate], bis (isocyanate methyl) cyclohexane, tetramethylene diisocyanate, hexamethylene diisocyanate, methylene diisocyanate, isophorone diisocyanate Aliphatic or alicyclic polyisocyanate compounds; cyclized polymers or vinyls of these polyisocyanate compounds Tsu DOO body; or a combination thereof can be mentioned.

  In particular, aromatic polyisocyanate compounds such as tolylene diisocyanate, xylylene diisocyanate, phenylene diisocyanate, diphenylmethane-2,4'-diisocyanate, diphenylmethane-4,4'-diisocyanate, crude MDI and the like are more preferable for corrosion resistance.

  On the other hand, the isocyanate blocking agent is blocked by adding 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). When heated to about 200 ° C., it is desirable that the blocking agent can be dissociated to regenerate free isocyanate groups.

  Examples of the blocking agent used in the blocked polyisocyanate curing agent include oxime compounds such as methyl ethyl ketoxime and cyclohexanone oxime; phenol compounds such as phenol, para-t-butylphenol and cresol; n-butanol and 2-ethyl Aliphatic alcohols such as hexanol; Aromatic alkyl alcohols such as phenyl carbinol and methyl phenyl carbinol; Ether alcohol compounds such as ethylene glycol monobutyl ether and diethylene glycol monoethyl ether; Lactams such as ε-caprolactam and γ-butyrolactam System compounds; and the like.

  As a blending ratio of the polyol-modified amino group-containing modified epoxy resin (A) and the blocked polyisocyanate curing agent in the cationic electrodeposition coating composition of the present invention, the above-described component polyol-modified amino group-containing modified epoxy resin (A) and the blocked composition are used. Based on the total solid mass of the polyisocyanate curing agent, the polyol-modified amino group-containing modified epoxy resin (A) is 50 to 95% by mass, preferably 60 to 90% by mass, and the blocked polyisocyanate curing agent (B). 5 to 50% by mass, preferably 10 to 40% by mass. Outside the range, any of paint properties, chipping resistance, and warm salt water immersion resistance may be impaired.

  In addition, manufacture of the cationic electrodeposition coating material which contains a polyol modified amino group containing modified epoxy resin (A) as a resin component can be performed as follows, for example. In addition to the polyol-modified amino group-containing modified epoxy resin (A) and the blocked polyisocyanate curing agent, various additives such as surfactants and surface modifiers, organic solvents, etc. are mixed thoroughly to obtain a compounded resin. The prepared resin is neutralized with an organic carboxylic acid or the like, and water-solubilized or water-dispersed to obtain an emulsion. In addition, generally publicly known organic carboxylic acid can be used for neutralization of compound resin, but especially acetic acid, formic acid, lactic acid, or a mixture thereof is preferred. Next, a cationic electrodeposition paint can be prepared by adding a pigment dispersion paste to the emulsion and adjusting with water.

  The above-mentioned pigment dispersion paste is a dispersion in which colored pigments, rust preventive pigments, extender pigments, and the like are dispersed in advance in fine particles. For example, a pigment dispersion resin, a neutralizing agent and pigments are blended, and a ball mill, a sand mill, A pigment dispersion paste can be prepared by dispersing in a dispersion mixer such as a pebble mill.

  As the pigment dispersion resin, known resins can be used. For example, resins having a hydroxyl group and a cationic group, surfactants, etc., or tertiary amine type epoxy resins, quaternary ammonium salt type epoxy resins, and tertiary sulfonium salts. Resins such as type epoxy resins can be used. The amount of the pigment dispersant used is preferably 1 to 150 parts by weight, particularly 10 to 100 parts by weight per 100 parts by weight of pigments.

  The pigments can be used without particular limitation, for example, colored pigments such as titanium oxide, carbon black, bengara, etc .; extender pigments such as clay, mica, barita, calcium carbonate, silica; aluminum phosphomolybdate, aluminum tripolyphosphate, Rust preventive pigments such as zinc oxide (zinc white) can be added.

Furthermore, a bismuth compound can be contained for the purpose of inhibiting corrosion or preventing rust. Examples of the bismuth compound include bismuth oxide, bismuth hydroxide, basic bismuth carbonate, bismuth nitrate, bismuth silicate, and organic acid bismuth.
In addition, for the purpose of improving the coating curability, organic tin compounds such as dibutyltin dibenzoate, dioctyltin oxide, and dibutyltin oxide can be used, and rust preventive pigments such as zinc oxide (zinc white) and / or Alternatively, by applying (increasing) and / or refining pigments that are bismuth compounds, it is possible to improve the coating curability without containing an organic tin compound. The blending amount of these pigments ranges from 1 to 100 parts by weight, particularly from 10 to 50 parts by weight, per 100 parts by weight of the total solid content of the polyol-modified amino group-containing modified epoxy resin (A) and the blocked polyisocyanate curing agent. The inside is preferable.

  The organic solvent that can be used in the cationic electrodeposition coating composition of the present invention is, for example, alcohol-based, for example, methyl alcohol, ethyl alcohol, n-butyl alcohol, isopropyl alcohol, 2-ethylhexanol, benzyl alcohol, ethylene glycol, propylene. Glycol; ether type, for example, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, ethylene glycol mono 2-ethylhexyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monophenyl ether, 3-methyl -3-Methoxybutanol, diethylene glycol monoethyl ether, diethylene glycol monobutyl Ether; ketone such as acetone, methyl isobutyl ketone, cyclohexanone, isophorone, acetyl acetone; esters, for example, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate and mixtures thereof.

  Examples of the coated object of the cationic electrodeposition coating composition of the present invention include automobile bodies, motorcycle parts, household equipment, other equipment, and the like, and any metal can be used without particular limitation. Examples of the metal plate to be coated include cold-rolled steel plate, alloyed hot-dip galvanized steel plate, electrogalvanized steel plate, electrogalvanized steel double-layer plated steel plate, organic composite plated steel plate, Al plate, Mg plate, and these metals. The surface of the plate may be subjected to surface treatment such as phosphate chemical treatment or chromate treatment after washing the surface such as alkali degreasing as required.

  The cationic electrodeposition coating composition can be applied to a desired substrate surface by electrodeposition coating. Cationic electrodeposition coating is generally an electrodeposition paint diluted with deionized water or the like to have a solid content concentration of about 5 to 40% by mass and further adjusted to a pH in the range of 5.5 to 9.0. The electrodeposition bath made of the composition can be usually performed by adjusting the bath temperature to 15 to 35 ° C. and energizing the article to be coated as a cathode under a load voltage of 100 to 400V. After electrodeposition, usually ultrafiltrate (UF filtrate), reverse osmosis permeate (RO water), industrial water, pure water, etc. are sufficient to remove the cationic electrodeposition paint that has adhered to the object. Wash with water.

  Although the film thickness of an electrodeposition coating film is not specifically limited, In general, it can be in the range of 5 to 40 μm, preferably 12 to 30 μm based on the dry coating film. The coating film is baked and dried by using a drying facility such as an electric hot air dryer or a gas hot air dryer, and the coating surface temperature is 110 ° C. to 200 ° C., preferably 140 to 180 ° C. Then, the electrodeposition coating film is heated for 10 minutes to 180 minutes, preferably 20 minutes to 50 minutes. The coating film can be cured by baking and drying.

  Hereinafter, the present invention will be described in more detail with reference to Production Examples, Examples, and Comparative Examples, but the present invention is not limited thereto. In each example, “parts” indicates mass parts, and “%” indicates mass%.

Production and Production Example 1 of Amino Group-Containing Modified Epoxy Resin (A) Example 1
400 parts of PP-400 (manufactured by Sanyo Chemical Co., Ltd., trade name, polypropylene glycol molecular weight 400) and 300 parts of ε-caprolactone were added, and the temperature was raised to 130 ° C. Thereafter, 0.01 part of tetrabutoxytitanium was added and the temperature was raised to 170 ° C. Sampling was carried out over time while maintaining this temperature, the amount of unreacted ε-caprolactone was monitored by infrared absorption spectrum measurement, and the mixture was cooled when the reaction rate reached 98% or more to obtain modifier 1.
Next, 1000 parts of jER828EL (Note 1), 400 parts of bisphenol A and 0.2 part of dimethylbenzylamine were added to another flask and reacted at 130 ° C. until an epoxy equivalent of 750 was reached.
Next, 100 parts of ε-caprolactone and 0.05 part of tetrabutoxytitanium were added, and the temperature was raised to 170 ° C. While maintaining this temperature, sampling was performed over time, the amount of unreacted ε-caprolactone was monitored by infrared absorption spectrum measurement, and cooling was performed when the reaction rate reached 98% or more. Next, 100 parts of modifier 1, 140 parts of diethanolamine and 65 parts (purity 84%) of diethylenetriamine ketimine were added to this product and reacted at 120 ° C. for 4 hours, and then 400 parts of ethylene glycol monobutyl ether was added. A base resin No. 56 having an amine value of 56 and a resin solid content of 80%. 1 was obtained.
(Note 1) jER828EL: manufactured by Japan Epoxy Resin Co., Ltd., trade name, epoxy resin, epoxy equivalent 190, molecular weight 350.

Production Example 2 Base resin no. Example 2
300 parts of ε-caprolactone was added to 1000 parts of PP-1000 (manufactured by Sanyo Chemical Co., Ltd., trade name, polypropylene glycol molecular weight 1000), and the temperature was raised to 130 ° C. Thereafter, 0.01 part of tetrabutoxytitanium was added and the temperature was raised to 170 ° C. Sampling was carried out over time while maintaining this temperature, the amount of unreacted ε-caprolactone was monitored by infrared absorption spectrum measurement, and when the reaction rate reached 98% or more, cooling was performed to obtain denaturant 2.
Next, 1000 parts of jER828EL (Note 1), 400 parts of bisphenol A and 0.2 part of dimethylbenzylamine were added to another flask and reacted at 130 ° C. until an epoxy equivalent of 750 was reached.
Next, 100 parts of ε-caprolactone and 0.05 part of tetrabutoxytitanium were added, and the temperature was raised to 170 ° C. While maintaining this temperature, sampling was performed over time, the amount of unreacted ε-caprolactone was monitored by infrared absorption spectrum measurement, and cooling was performed when the reaction rate reached 98% or more. Next, 100 parts of modifier 2, 140 parts of diethanolamine and 65 parts (purity 84%) of diethylenetriamine were added to this product and reacted at 120 ° C. for 4 hours, and then 400 parts of ethylene glycol monobutyl ether was added. A base resin No. 56 having an amine value of 56 and a resin solid content of 80%. 2 was obtained.

Production Example 3 Base resin no. Production Example 3 PP-400 (manufactured by Sanyo Chemical Co., Ltd., trade name, polypropylene glycol molecular weight 400) was added to 300 parts of ε-caprolactone and heated to 130 ° C. Thereafter, 0.01 part of tetrabutoxytitanium was added and the temperature was raised to 170 ° C. Sampling was carried out over time while maintaining this temperature, the amount of unreacted ε-caprolactone was monitored by infrared absorption spectrum measurement, and the mixture was cooled when the reaction rate reached 98% or more to obtain modifier 1.
Next, 1000 parts of jER828EL (Note 1), 400 parts of bisphenol A and 0.2 part of dimethylbenzylamine were added to another flask and reacted at 130 ° C. until an epoxy equivalent of 750 was reached. Next, 200 parts of modifying agent 1, 140 parts of diethanolamine and 65 parts of diethylenetriamine ketiminate were added and reacted at 120 ° C. for 4 hours, and then 400 g of ethylene glycol monobutyl ether was added to give an amine value of 56, a resin solid content of 80 % Substrate resin No. 3 was obtained.

Production Example 4 Base resin No. Production Example 4 No. 4 390 parts of bisphenol A and 0.2 part of dimethylbenzylamine were added to 1010 parts of jER828EL (Note 1) and reacted at 130 ° C. until the epoxy equivalent was 800. Next, 160 g of diethanolamine and 65 parts of a diethylenetriamine ketiminate were added and reacted at 120 ° C. for 4 hours, and then 355 parts of ethylene glycol monobutyl ether was added. 4 was obtained.

Production Example 5 Base resin No. 5 Production Example PP-400 (manufactured by Sanyo Chemical Co., Ltd., trade name, polypropylene glycol molecular weight 400) was added to 300 parts of ε-caprolactone and heated to 130 ° C. Thereafter, 0.01 part of tetrabutoxytitanium was added and the temperature was raised to 170 ° C. Sampling was carried out over time while maintaining this temperature, the amount of unreacted ε-caprolactone was monitored by infrared absorption spectrum measurement, and the mixture was cooled when the reaction rate reached 98% or more to obtain modifier 1.
Next, 1000 parts of jER828EL (Note 1), 400 parts of bisphenol A and 0.2 part of dimethylbenzylamine were added to another flask and reacted at 130 ° C. until an epoxy equivalent of 750 was reached. Next, 333 parts of modifying agent 1, 126 parts of diethanolamine and 65 parts of ketimine compound of diethylenetriamine were added and reacted at 120 ° C. for 4 hours, and then 425 g of ethylene glycol monobutyl ether was added to give an amine value of 48, a resin solid content of 80 % Substrate resin No. 5 was obtained.

Production Example 6 of Blocked Polyisocyanate Curing Agent (B) Production Example of Curing Agent In a reaction vessel, 270 parts of Cosmonate M-200 (trade name, made by Mitsui Chemicals, Crude MDI) and 127 parts of methyl isobutyl ketone were added. In addition, the temperature was raised to 70 ° C. In this, 236 parts of ethylene glycol monobutyl ether was added dropwise over 1 hour, then heated to 100 ° C., sampled over time while maintaining this temperature, and unreacted isocyanate group was measured by infrared absorption spectrum measurement. It was confirmed that the absorption of the resin was lost, and a curing agent having a resin solid content of 80% was obtained.

Production Example of emulsion 7 emulsion No. Production Example 1 Substrate resin No. obtained in Production Example 1 1 was mixed with 75 parts (solid content: 70 parts), 37.5 parts (solid content: 30 parts) of the curing agent obtained in Production Example 6, and further mixed with 13 parts of 10% acetic acid and stirred uniformly. , 156 parts of deionized water was added dropwise over about 15 minutes while stirring vigorously, and emulsion No. 34 having a solid content of 34% was added. 1 was obtained.

Production Examples 8 to 11 Emulsion No. 2-No. Production Example No. 5 Emulsion No. 5 was prepared in the same manner as in Production Example 7 except that the contents of Table 1 were used. 2-No. 5 was obtained.

Production Example 12 Production Example of Pigment Dispersing Resin jER828EL (Note 1) 1010 parts, 390 parts of bisphenol A, Plaxel 212 (polycaprolactone diol, Daicel Chemical Industries, Ltd., trade name, weight average molecular weight of about 1,250) 240 And 0.2 part of dimethylbenzylamine were added and reacted at 130 ° C. until the epoxy equivalent was about 1,090.
Next, 134 parts of dimethylethanolamine and 150 parts of a 90% aqueous lactic acid solution were added and reacted at 120 ° C. for 4 hours. Next, methyl isobutyl ketone was added to adjust the solid content, and an ammonium salt resin-based pigment dispersion resin having a solid content of 60% was obtained. The ammonium salt concentration of the dispersing resin was 0.78 mmol / g.

Production Example 13 Production Example of Pigment Dispersion Paste 8.3 parts of pigment dispersion resin obtained in Production Example 12 (solid content 5 parts), titanium oxide 14.5 parts, refined clay 7.0 parts, carbon Black 0.3 parts, dioctyl tin oxide 1 part, bismuth hydroxide 1 part and deionized water 20.3 parts were added and dispersed in a ball mill for 20 hours. 1 was obtained.

[Manufacture of cationic electrodeposition coatings]
Example 1
Emulsion No. obtained in Production Example 7 1 was added to 294 parts (solid content: 100 parts), 55% pigment dispersion paste obtained in Production Example 13 was added to 52.4 parts (solid content: 28.8 parts), and deionized water (297.6 parts) was added. % Cationic electrodeposition paint no. 1 was produced.

Example 2, Comparative Examples 1-3
In the same manner as in Example 1, a cationic electrodeposition paint No. 1 having the blending contents shown in Table 2 was used. 2-No. 5 was produced.

[About test plate]
Cold-rolled steel sheet (0.8 mm x 150 mm x 70 mm) or alloyed hot-dip galvanized steel sheet (0.8 mm x 150 mm) subjected to chemical conversion treatment with Palbond # 3020 (manufactured by Nippon Parkerizing Co., Ltd., trade name, zinc phosphate chemical conversion treatment agent) × 70 mm) was used as a test plate. Table 3 shows the results of tests performed using the obtained test plates.

(Note 2) Finishing property: A cold-rolled steel plate (0.8 mm x 150 mm x 70 mm) test plate was immersed in each cationic electrodeposition paint and subjected to electrodeposition coating. The surface roughness of the electrodeposition coating film on the outer plate was measured with a surf test 301 (trade name, surface roughness measuring machine, manufactured by Mitutoyo Corporation).
○ indicates that the Ra value is less than 0.25 μm. Δ indicates that the Ra value is 0.25 μm or more and less than 0.35 μm.

(Note 3) Chipping resistance: Electrodeposition coating is performed on a test plate of an alloyed hot-dip galvanized steel sheet (0.8 mm x 150 mm x 70 mm) using each cationic electrodeposition paint so as to have a dry film thickness of 20 µm. And baked by a hot air dryer at 170 ° C. for 20 minutes. Next, WP-306 (manufactured by Kansai Paint Co., Ltd., aqueous intermediate coating) was spray-coated so that the cured film thickness was 25 μm, and then baked at 140 ° C. for 30 minutes with an electric hot air dryer.
Furthermore, after spray-coating Neo Amirac 6000 (manufactured by Kansai Paint Co., Ltd., top coating) on the intermediate coating film so as to have a cured film thickness of 35 μm, it was baked at 140 ° C. for 30 minutes with an electric hot air drier. A coated plate was prepared.
The multilayer coating plate is fixed to the specimen holder of the chipping tester (Suga Test Instruments Co., Ltd., stepping stone testing machine "JA-400") so that the coating surface is perpendicular to the stone outlet. After spraying 50 g of granite crushed stone with a particle size of 7 with 0.294 MPa (3 kgf / cm ² ) compressed air at −20 ° C., cloth adhesive tape (Fuji Kogyo Co., Ltd.) was applied to the coated surface. And after peeling it off rapidly, the generation | occurrence | production degree of the crack of a coating film, etc. was observed visually, and the following reference | standard evaluated.
◎ indicates that the size of the scratch is 1.0 mm or less in diameter and the top coating film is partially scratched.
○, the size of the scratch is more than 1.0 mm in diameter and 1.5 mm or less, and the intermediate coating film is partially exposed,
Δ, the size of the scratch is over 1.5 mm in diameter and 2.0 mm or less, part of the intermediate coating film is missing, the electrodeposition coating film or steel plate is exposed,
X indicates that the size of the scratch exceeds 2.0 mm in diameter, and the intermediate coating film is greatly exposed, or the intermediate coating film is lost and the electrodeposition coating or steel sheet is exposed, and the appearance is remarkably impaired. Yes.

(Note 4) Resistance to warm salt water: Electrodeposition coating is performed on a cold-rolled steel plate (0.8 mm x 150 mm x 70 mm) using a cationic electrodeposition paint so that the dry film thickness is 20 μm. The obtained coated plate was immersed in 5% by mass of salt water at 50 ° C. for 840 hours, and a cellotape (registered trademark) peel test was performed to evaluate the peeled rate (%).
◎: less than 5% of the coating film is peeled off with respect to the ratio of the entire coating film.
△ is a ratio of peeling of the coating film with respect to the ratio of the entire coating film is 10% or more and less than 20%,
X is 20% or more when the coating film is peeled off with respect to the entire coating film.

  INDUSTRIAL APPLICABILITY The present invention can provide a coated article that is excellent in finish, chipping resistance, and warm salt water immersion.

Claims (4)

Polyol compound (a2) obtained by adding caprolactone to a compound having a plurality of active hydrogen groups to a modified epoxy resin (a1) obtained by adding caprolactone to a hydroxyl group-containing epoxy resin having an epoxy equivalent of 180 to 2500 And a cationic electrodeposition coating composition containing a polyol-modified amino group-containing epoxy resin (A) obtained by reacting the amino group-containing compound (a3). The cationic electrodeposition coating composition according to claim 1, wherein the active hydrogen group in the compound having 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 cationic electrodeposition coating composition according to claim 1 or 2, comprising a blocked polyisocyanate compound. An article coated with the cationic electrodeposition coating composition according to any one of claims 1 to 3.