JP2006282716A - Anionic electrodeposition coating and coated article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To develop an anionic electrodeposition coating which gives coated products having excellent non-adhesiveness, finishes, corrosion resistance, coating film adhesiveness and the like, and is used for industrial machine parts, automotive parts, and the like. <P>SOLUTION: (1) This anionic electrodeposition coating comprises 100 pts.mass of the solid content of a base resin and 1 to 30 pts.mass of a resol type phenolic resin. (2) The above-mentioned anionic electrodeposition coating, wherein a fatty acid-modified acrylic resin (B) is contained as the base resin. (3) The above-mentioned anionic electrodeposition coating, wherein the fatty acid-modified acrylic resin (B) is obtained by reacting a radically polymerizable unsaturated monomer mixture containing an alkoxysilyl group-containing polymerizable monomer in an amount of 0.1 to 10 mass% based on the total amount of the solid contents of the radical polymerizable unsaturated monomers. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a pollution-free anionic electrodeposition coating material that does not contain harmful metals such as lead compounds and chromium compounds, and can provide coating performance excellent in non-adhesiveness, finish, corrosion resistance, and coating adhesion.

Electrodeposition paints are used in a wide range of applications including automobile parts and industrial machine parts, and those having various characteristics have been developed. For example, a thermosetting anion electrodeposition coating material, for example, a coating material that has a large heat capacity and does not sufficiently transfer the heat of the drying oven, or a coating material that incorporates plastic or rubber (for example, a tractor) Room temperature drying type anionic electrodeposition coatings are used in industrial machines such as In addition, the use of lead compounds and chromium compounds in electrodeposition paints has been restricted in view of recent environmental issues.
Conventionally, as an invention related to room temperature curing type electrodeposition paints that do not use harmful metals, electrodeposition paints containing zinc phosphate, calcium zinc phosphite, calcium zinc phosphite strontium, calcium molybdate, aluminum phosphomolybdate, etc. as rust inhibitors [Patent Document 1]. Although these compounds are relatively inexpensive, they have insufficient anticorrosion properties. Therefore, when they are contained in a large amount in an electrodeposition coating material in order to ensure the anticorrosion properties, the finishability and paint stability are impaired. Further, the non-adhesiveness and curability of the coating film were insufficient.

  In addition, there is an invention relating to an anionic electrodeposition paint containing a fatty acid-modified acrylic resin modified with a fatty acid-modified acrylic resin and / or an epoxy resin, an organic solvent, a rust inhibitor, and / or a bismuth compound [Patent Document 2]. In Patent Document 2, a coating film having excellent anticorrosion and finishing properties can be obtained without containing a lead compound or a chromium compound, but non-adhesiveness and curability are insufficient. For this reason, lead compounds and chromium compounds are not used, and non-adhesiveness is good (when left at room temperature, fingerprints and scratches are not touched when touched), curability, finish, There has been a demand for a pollution-free anionic electrodeposition coating material that is excellent in corrosion resistance and coating stability.

JP 2003-277679 A JP 2004-277805 A

  The problem to be solved is to provide an anionic electrodeposition paint that does not use a lead compound or a chromium compound, has good non-adhesiveness, and is excellent in finish, corrosion resistance, and coating film adhesion.

  As a result of intensive studies to solve the above problems, the present inventors have found that an anionic electrodeposition paint containing a resol-type phenol resin (A) is non-adhesive, curable, finished, anticorrosive, and paint stable. As a result, the present invention has been completed.

  The anion electrodeposition coating material of the present invention can provide a coated article excellent in non-adhesiveness, finish, anticorrosion, and coating film adhesion without using harmful metals such as lead and chromium. The reason is considered that the resol-type phenol resin (A) is excellent in adhesion to the material and permeation-preventing ability, is compatible with the resin component, and crosslinks with the base resin during forced drying for water scattering.

The material to be coated suitable for the anion electrodeposition coating of the present invention is not limited at all as long as it is a material having a metal surface that can be electrodeposited. For example, iron, aluminum, tin, zinc And alloys containing these metals, such as automobile parts, industrial machine parts, electrical products, building materials, etc. Examples include parts that are built in and cannot be heated. These coated materials are preferably subjected to surface treatment such as zinc phosphate before being immersed in the anion electrodeposition coating material in order to improve the corrosion resistance. The anion electrodeposition coating material of the present invention is characterized by containing 1 to 30 parts by mass of the resol type phenol resin (A) with respect to 100 parts by mass of the solid content of the base resin.

Resol type phenol resin (A):
The resol-type phenol resin (A) is obtained by introducing a methylol group by heating and condensing a phenol and formaldehyde in the presence of a reaction catalyst, and the introduced methylol group is alkyl etherified. It may be.
As a phenol component which comprises the said resol type phenol resin (A), for example,
Bifunctional such as o-cresol, p-cresol, p-tert-butylphenol, p-ethylphenol, 2,3-xylenol, 2,5-xylenol, p-tert-aminophenol, p-nonylphenol, p-cyclohexylphenol Functional phenols, coalic acid, m-cresol, m-ethylphenol, 3,5-xylenol, trifunctional phenols such as m-methoxyphenol, monofunctional phenols such as 2,4-xylenol, 2,6-xylenol , Tetrafunctional phenols such as bisphenol B and bisphenol F, or a combination of two or more. Further, it is desirable not to use a bisphenol A type phenol resin because bisphenol A may be eluted. Examples of formaldehydes include formaldehyde, paraformaldehyde, and trioxane, which can be used alone or in combination of two or more.

  The compounding amount of the resol type phenol resin (A) is in the range of 1 to 30 parts by mass, preferably 5 to 25 parts by mass, more preferably 10 to 20 parts by mass with respect to 100 parts by mass of the solid content of the resin component. Is suitable from the viewpoint of the balance of non-adhesiveness, finish, anticorrosion, coating film adhesion and paint stability. The resol type phenol resin (A) can be used in any of a room temperature curing type anion electrodeposition coating material and a thermosetting type anion electrodeposition coating material.

About room temperature curing type anion electrodeposition coating material As the room temperature curing type anion electrodeposition coating material, the following fatty acid-modified acrylic resin (B) and / or epoxy resin-modified / fatty acid-modified acrylic resin (C) are suitable as the base resin. Can be used. By using the resin, for example, a dry coating film (Note 1) of 24 hours to 10 days, preferably 3 days to 7 days can be obtained at room temperature (50 ° C. or less).
Dry coating: Forced drying over 50 ° C and 100 ° C or less for 5 to 40 minutes before drying at room temperature (50 ° C or less) in order to promote moisture scattering from the object. You may go.

Fatty acid-modified acrylic resin (B):
The fatty acid-modified acrylic resin (B) is usually a fatty acid-modified acrylic monomer (b ₁ ), a carboxyl group-containing radical polymerizable unsaturated monomer (b ₂ ), and other radical polymerizable unsaturated monomers. It is obtained by copolymerizing (b ₃ ).
The fatty acid-modified acrylic monomer (b ₁ ) can be obtained, for example, by reacting an unsaturated fatty acid with a hydroxyl group-containing polymerizable unsaturated monomer or an epoxy group-containing polymerizable unsaturated monomer.

  Examples of unsaturated fatty acids include aliphatic monocarboxylic acids having an unsaturated group in which at least two or more double bonds are not conjugated to each other in one molecule, in particular, at least two nonconjugated double bonds. The dry oil fatty acid and semi-dry oil fatty acid contained are effective.

  Here, the dry oil fatty acid generally means an unsaturated fatty acid having an iodine value exceeding 130, and the semidry oil fatty acid means an unsaturated fatty acid having an iodine value of 100 to 130. Examples of such unsaturated fatty acids include safflower oil fatty acid, linseed oil fatty acid, soybean oil fatty acid, sesame oil fatty acid, poppy oil fatty acid, eno oil fatty acid, hemp oil fatty acid, grape kernel oil fatty acid, corn oil fatty acid, tall oil Fatty acids, sunflower oil fatty acids, cottonseed oil fatty acids, walnut oil fatty acids, rubber seed oil fatty acids and the like can be mentioned, and these fatty acids can be used alone or in admixture of two or more.

The hydroxyl group-containing polymerizable unsaturated monomer that is reacted with an unsaturated fatty acid to obtain the fatty acid-modified acrylic monomer (b ₁ ) has _one hydroxyl group in the ester residue portion of acrylic acid or methacrylic acid, and Examples thereof include those containing 2 to 24, preferably 2 to 8 carbon atoms in the ester residue portion (hereinafter, hydroxyl group-containing acrylic ester).

Such hydroxyl group-containing acrylic esters include hydroxyalkyl acrylates and hydroxyalkyl methacrylates, specifically, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, and the like. Can be mentioned. The fatty acid-modified acrylic monomer (b ₁ ) can be obtained by reacting an unsaturated fatty acid and a hydroxyl group-containing acrylic ester in an inert solvent in the presence of an esterification catalyst.

The amount of these unsaturated fatty acids to be used can be appropriately changed according to the requirements of the coating film performance. In general, however, the total amount of the solid content of the monomer constituting the fatty acid-modified acrylic resin (B) The range of 5 to 65% by mass, preferably 10 to 60% by mass is preferable. Further, if necessary, an unsaturated fatty acid having a conjugated double bond such as kiri oil fatty acid, eutica oil fatty acid, dehydrated castor oil fatty acid, and high diene fatty acid is used within a range of 30% by mass or less, preferably 20% by mass or less. Also good.

The reaction conditions for the production of the fatty acid-modified acrylic monomer (b ₁ ) are generally about 100 to about 180 ° C., preferably 120 to 160 ° C., and the reaction time is about 0.5 to about 10 hours, preferably It can be performed in about 1 to about 6 hours. The hydroxyl group-containing acrylic ester can usually be used at a ratio of 0.5 to 1.9 mol per mol of unsaturated fatty acid, preferably 1.0 to 1.5 mol per mol of unsaturated fatty acid. Use as a percentage.

Examples of the esterification catalyst used in the above reaction include sulfuric acid, aluminum sulfate,
Examples thereof include potassium hydrogen sulfate, p-toluenesulfonic acid, hydrochloric acid, methyl sulfate, phosphoric acid and the like. In the range of 0.05 to 2.0% by mass with respect to the total amount of unsaturated fatty acid and hydroxyl group-containing acrylic ester. It is preferable to use it.

The inert solvent is preferably a water-immiscible organic solvent that can be refluxed at a temperature of 180 ° C. or lower. For example, aromatic hydrocarbons such as benzene, toluene, and xylene; aliphatic carbonization such as heptane, hexane, and octane. Hydrogen is mentioned.
In the above reaction, if necessary, a polymerization inhibitor such as hydroquinone, methoxyphenol, tert-butylcatechol, benzoquinone, etc. is added to the reaction system to polymerize the hydroxyl group-containing acrylic ester and / or the resulting fatty acid-modified acrylic ester. Can be suppressed. In the above reaction, esterification occurs between the hydroxyl group of the hydroxyl group-containing acrylic ester and the carboxyl group of the unsaturated fatty acid, and an acrylic ester modified with the unsaturated fatty acid is obtained.

In addition, an epoxy group-containing polymerizable unsaturated monomer that is reacted with an unsaturated fatty acid to obtain a fatty acid-modified acrylic monomer (b ₁ ) is a glycidyl group-containing acrylic acid ester or methacrylic acid ester such as glycidyl methacrylate and an unsaturated monomer. It can be obtained by reacting a saturated fatty acid by an acid / epoxy reaction. In this case, it is preferable to use a polymerization inhibitor as necessary as described above.

Examples of the carboxyl group-containing radical polymerizable unsaturated monomer (b ₂ ) include acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, 2-carboxyethyl (meth) acrylate, 2-carboxypropyl ( Examples include meth) acrylate and 5-carboxypentyl (meth) acrylate.

As other radical polymerizable unsaturated monomer (b ₃ ), acrylic acid or methacrylic acid such as 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate hydroxyalkyl (meth) acrylates of C ₂ -C _8, and (poly) ethylene glycol - mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, hydroxyl group-containing radically polymerizable, such as polybutylene glycol mono (meth) acrylate unsaturated Saturated monomers;
These hydroxyl group-containing radically polymerizable unsaturated monomers and β-propiolactone, dimethylpropiolactone, butyrolactone, γ-valerolactone, γ-caprolactone, γ-caprolactone, γ-laurilolactone, ε- Product names such as reaction products with lactone compounds such as caprolactone and δ-caprolactone include Plaxel FM-1 (manufactured by Daicel Chemical Industries, trade name, caprolactone-modified (meth) acrylic acid hydroxy esters), Plaxel FM-2. (Same as left), Placcel FM-3 (same as left), Placcel FA-1 (same as left), Placcel FA-2 (same as left), Placcel FA-3 (same as left), etc .; for example, methyl (meth) acrylate, ethyl (meth) acrylate , Propyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth Acrylate, octyl (meth) acrylate, lauryl (meth) acrylate, alkyl or cycloalkyl esters of _C 1 _{-C 18} (meth) acrylic acid such as cyclohexyl (meth) acrylate;
For example, vinyltrimethoxysilane, vinylmethyldimethoxysilane, vinyldimethylmethoxysilane, vinyltriethoxysilane, vinylmethyldiethoxysilane, vinyldimethylethoxysilane, vinyltripropoxysilane, vinylmethyldipropoxysilane, vinyldimethylpropoxysilane, γ- Alkoxysilyl group-containing polymerizable unsaturated monomers such as (meth) acryloxypropyltrimethoxysilane, γ- (meth) acryloxypropylmethyldimethoxysilane, γ- (meth) acryloxypropyldimethylmethoxysilane;
For example, glycidyl group-containing radical polymerizable unsaturated monomers such as glycidyl (meth) acrylate and allyl glycidyl ether; ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetra Ethylene glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, 1,4-butanediol diacrylate, glycerol di (meth) acrylate, glycerol tri (meth) acrylate, trimethylolpropane di (meth) Acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) ) Acrylate, dipentaerythritol penta (meth) acrylate, hydroxyisocyanurate tri (meth) acrylate, neopentyl glycol diacrylate, 1,6-hexanediol diacrylate, glycerol allyloxy di (meth) acrylate, 1,1,1 -Tris (hydroxymethyl) ethane di (meth) acrylate, 1,1,1-tris (hydroxymethyl) ethane tri (meth) acrylate, triallyl isocyanurate, triallyl trimellitate, diallyl terephthalate, diallyl phthalate, diallyl isophthalate, Polyvinyl radical polymerizable unsaturated monomers having two or more polymerizable unsaturated bonds in one molecule such as pentaerythritol diallyl ether and divinylbenzene; styrene, α-methylstyrene Aromatic radical polymerizable unsaturated monomers such as ethylene, vinyl toluene and α-chlorostyrene;
For example, nitrogen-containing alkyl (meth) acrylates such as N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, Nt-butylaminoethyl (meth) acrylate; acrylamide, methacrylamide N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N-methylol (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, N, N-dimethyl (meth) ) Polymerizable amides such as acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, N, N-dimethylaminoethyl (meth) acrylamide; Polymerizable nitriles such as acrylonitrile and methacrylonitrile; Nitrogen-containing systems such as allylamine Radical polymerizable unsaturated monomer; and the like.

  For example, a radically polymerizable unsaturated monomer having a nitrogen-containing heterocyclic ring can be blended. The radical-polymerizable unsaturated monomer having a nitrogen-containing heterocyclic ring includes monomers having a monocyclic or polycyclic heterocyclic ring containing 1 to 2, preferably 1 or 2 nitrogen atoms bonded to a vinyl group. In particular, the monomers shown in the following (1) to (6) can be mentioned.

  (1): For example, vinylpyrrolidones such as 1-vinyl-2-pyrrolidone and 1-vinyl-3-pyrrolidone; (2): For example, 2-vinylpyridine, 4-vinylpyridine, 5-methyl-2-vinyl Vinylpyridines such as pyridine and 5-ethyl-2-vinylpyridine; (3): For example, vinylimidazoles such as 1-vinylimidazole and 1-vinyl-2-methylimidazole; (4): For example, N-vinylcariba (5): for example, vinyl quinolines such as 2-vinyl quinoline; (6): for example, vinyl piperidines such as 3-vinyl piperidine, N-methyl-3-vinyl piperidine; The monomers can be used alone or in combination of two or more.

The blending ratio of the above fatty acid-modified acrylic monomer (b ₁ ), the carboxyl group-containing radical polymerizable unsaturated monomer (b ₂ ) and the other radical polymerizable unsaturated monomer (b ₃ ) is simply The monomer (b ₁ ) is 7 to 94% by mass, preferably 10 to 80% by mass, the monomer (b ₂ ) is 3 to 20% by mass, preferably 5 to 15% by mass, and the monomer (b ₃ ). Is in the range of 6 to 93% by mass, preferably 20 to 90% by mass.

Further, based on the total solid content of the monomer (b ₁ ), monomer (b ₂ ), and monomer (b ₃ ), the alkoxysilyl group-containing polymerizable unsaturated monomer is 0.1 to 0.1%. It was found that the content of 10% by mass, preferably 1 to 8% by mass, is preferable for improving non-adhesiveness, curability, finish, anticorrosion, and paint stability. Further, a matte coating film having a 60-degree specular gloss (Note 2) of 20 or less, particularly 15 or less can also be obtained.

(Note 2) 60 degree specular glossiness: Reflection when the glossiness of the coating is in accordance with the 60 degree specular glossiness of JIS K-5400 7.6 (1990) and the incident angle and the light receiving angle are 60 degrees, respectively. The percentage was measured and expressed as a percentage when the glossiness of the reference surface of the specular glossiness was taken as 100.
The copolymerization reaction of these monomers is carried out in a solvent in the presence of a polymerization catalyst at a reaction temperature of about 30 to 180 ° C., preferably 40 to 170 ° C., for about 1 to 20 hours, preferably 6 to 10 hours. This can be done by continuing the time reaction. The acid value of the fatty acid-modified acrylic resin (B) is in the range of 20 to 150 mgKOH / g, preferably in the range of 25 to 120 mgKOH / g.

The fatty acid-modified acrylic resin (B) is produced by the fatty acid-modified acrylic monomer (b ₁ ), the carboxyl group-containing radical polymerizable unsaturated monomer (b ₂ ), and other radical polymerizable unsaturated monomers. (B ₃ ) is mixed and obtained by carrying out a copolymerization reaction such as a solution polymerization method, an emulsion polymerization method, or a suspension polymerization method.

  The copolymerization reaction is carried out in an appropriate solvent in the presence of a polymerization catalyst, usually at a reaction temperature of about 0 to about 180 ° C., preferably about 40 to about 170 ° C., for about 1 to about 20 hours, preferably The resin can be obtained by continuing the reaction for about 6 to about 10 hours.

Epoxy resin modified / fatty acid modified acrylic resin (C):
Moreover, when high anticorrosion property is required as coating film performance, an epoxy resin-modified / fatty acid-modified acrylic resin (B) and an epoxy resin having an epoxy equivalent of 180 to 2500 are reacted. C) can also be used.
The epoxy resin can be obtained, for example, by a reaction between a polyphenol compound and an epihalohydrin such as epichlorohydrin. Examples of the polyphenol compound that can be used for forming the polyepoxide compound 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- Examples thereof include propane, bis (2-hydroxynaphthyl) methane, tetra (4-hydroxyphenyl) -1,1,2,2-ethane, 4,4-dihydroxydiphenylsulfone, phenol novolak, cresol novolak, and the like.

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

Here, n = 1 to 3 are preferable.

  Examples of such commercially available epoxy resins include those sold by Japan Epoxy Resins Co., Ltd. under the trade names of Epicoat 828EL, 1002, 1004, and 1007.

  When the epoxy resin-modified / fatty acid-modified acrylic resin (C) is produced, the mass ratio of the fatty acid-modified acrylic resin (C) and the epoxy resin having an epoxy equivalent of 180 to 2500 is a solid resin of the fatty acid-modified acrylic resin (B). The ratio of the epoxy resin to the minute is 0.01 to 50% by mass, preferably 0.1 to 35% by mass.

  As reaction conditions, the fatty acid-modified acrylic resin (B) and an epoxy resin can be mixed in an organic solvent, and the reaction can be performed at a reaction temperature of room temperature to 200 ° C. for 0.2 to 30 hours. Further, as a catalyst, a tertiary amine, a quaternary ammonium salt or the like that is publicly known for an acid / epoxy reaction can be used. The progress of the reaction can be grasped by following the decrease in the acid value of the resin by titration.

A room temperature curing type anionic electrodeposition coating is manufactured by mixing a pigment dispersion paste made by dispersing a pigment with a dispersing resin into an emulsion obtained by dispersing a base resin in water, and adding deionized water to solidify the paint. The content is obtained by adjusting the pH to 7.0 to 10.0 with a neutralizing agent, with the content of 5 to 30% by mass, preferably 10 to 20% by mass.
The above-mentioned emulsion is produced by using a resol-type phenol resin (A), a fatty acid-modified acrylic resin (B) and / or an epoxy resin-modified / fatty acid-modified acrylic resin (C), if necessary, an organic solvent, a repellant, a surface A regulator, a film-forming agent, etc. are added, 0.1-1.1 equivalent with respect to the carboxyl group of a fatty acid modified acrylic resin (B) or an epoxy resin modified / fatty acid modified acrylic resin (C), preferably 0.5-1 It is obtained by adding 0.0 equivalent of neutralizing agent, adding deionized water, and dispersing in water with a disper or the like.

  Examples of the neutralizing agent include ammonia, diethylamine, ethylethanolamine, diethanolamine, monoethanolamine, monopropanolamine, isopropanolamine, ethylaminoethylamine, hydroxyethylamine, triethylamine, tributylamine, diethylenetriamine and other organic amines, and Examples include alkali metal hydroxides such as caustic soda and caustic potash.

  The pigment dispersion paste is produced using, for example, a fatty acid-modified acrylic resin (B) and / or an epoxy resin-modified / fatty acid-modified acrylic resin (C), and other pigments such as titanium oxide, carbon black, bengara, etc. Color pigments of clay; extender pigments such as clay, talc, mica, barita, calcium carbonate, silica; rust preventive pigments such as aluminum phosphomolybdate and aluminum dihydrogen tripolyphosphate; curing catalysts such as zinc octylate and zinc formate; A rust preventive pigment such as bismuth, basic bismuth carbonate, bismuth nitrate, and bismuth silicate, a surface conditioner, a surfactant, and the like are appropriately blended and dispersed using ball mill dispersion or sand mill dispersion.

Moreover, as a rust inhibitor, [(xMHPO ₄ 3H ₂ O) · (ySiO ₂ ) · (mCaSiO ₃ ) · (nCaCO ₃ )] ··
(In the formula (1), M is a divalent metal selected from Mg and Ca, x, y and m are integers satisfying the following conditions: 1 ≦ x ≦ 3, 1 ≦ y ≦ 3, 1 ≦ m. ≦ 3,0 ≦ n ≦ 3), _{specifically,} can also be used _{2CaHPO 4 · 3H 2 O · 2SiO} 2 · CaSiO 3 · 2CaCO 3 like.

  In the room temperature curing type anion electrodeposition coating, the coating temperature is usually adjusted to 15 to 40 ° C., preferably 20 to 35 ° C., and the load voltage is 20 to 400 V, preferably 30 to 300 V. A coating film can be formed by energizing for 1 to 10 minutes. The film thickness of the coating film is not particularly limited, but in general, it is preferably in the range of 5 to 40 μm based on the dry coating film. Thereafter, the object to be coated is pulled up from the electrodeposition bath, and the coated surface is washed with water as necessary. Preferably, after 50 ° C. and 100 ° C. or lower, forced drying is performed for 5 to 40 minutes, and then 50 ° C. or lower. For 24 hours to 10 days, preferably 3 days to 7 days. The part to be coated is preferably a part having a large heat capacity and a part in which the coating film cannot be heated sufficiently, or a part incorporating a plastic or rubber.

About thermosetting anion electrodeposition coating The thermosetting anion electrodeposition coating is an anionic resin having a carboxyl group as a base resin, for example, an acrylic resin, a polyester resin having a carboxyl group and a hydroxyl group, Polyurethane resins, those known per se blended in ordinary anionic electrodeposition paints can be used. The resol type phenol resin (A) can be used as a crosslinking agent.

As said acrylic resin, it is obtained by copolymerizing a carboxyl group-containing radically polymerizable unsaturated monomer, and other radically polymerizable unsaturated monomers, and manufacture of a fatty acid modified acrylic resin (B) The carboxyl group-containing radical polymerizable unsaturated monomer (b ₂ ) and other radical polymerizable unsaturated monomer (b ₃ ) used in the above can be used. Examples of the method for copolymerizing these monomers include conventionally known solution polymerization methods. The number average molecular weight (Note 1) of the acrylic resin thus obtained is suitably 10,000 or less, particularly in the range of 4,000 to 8,000.
(Note 1) Number average molecular weight: Measured according to JIS K 0124-83, TS is used for the separation column.
Chromatogram obtained by RI refractometer using K GEL4000H _XL + G3000H _XL + G2500H _XL + G2000H _XL (manufactured by Tosoh Corporation) at 40 ° C with a flow rate of 1.0 ml / min and eluent with GPC tetrahydrofuran. And calculated from a calibration curve of polystyrene.

Furthermore, it is preferable that the thermosetting anion electrodeposition coating material contains other crosslinking agent in addition to the resol type phenol resin (A). Other crosslinking agents are not particularly limited, and examples thereof include melamine resins and block polyisocyanate compounds. Examples of the melamine resin include a methylolated melamine resin obtained by methylolating melamine with formaldehyde; an alkylated melamine resin obtained by etherifying this methylol group with a monoalcohol; a methylolated melamine resin having an imino group or an alkylated melamine resin. Can do. Further, in the etherification of the methylol group, a mixture alkylated using two or more monoalcohols may be used. Examples of the monoalcohol include methyl alcohol, ethyl alcohol, n-propyl alcohol, i-propyl alcohol, n-butyl alcohol, i-butyl alcohol, 2-ethylbutanol, 2-ethylhexanol and the like. Specifically, methylated melamine resin, imino group-containing methylated melamine resin, methylated / butylated melamine resin, imino group-containing methylated / butylated melamine resin, etc. are preferable, and imino group-containing methylated melamine resin is more preferable. .
As commercial products, for example, melamine resin satisfying such conditions is Cymel 202, Cymel 232, Cymel 235, Cymel 238, Cymel 254, Cymel 266, Cymel 267, Cymel 272, Cymel 285, Cymel 301, Cymel 303, Cymel. 325, Cymel 327, Cymel 350, Cymel 370, Cymel 701, Cymel 703, Cymel 736, Cymel 738, Cymel 771, Cymel 1141, Cymel 1156, Cymel 1158, etc. (above, manufactured by Nihon Cytec Industries, Inc.), Uban 120, 20HS, 2021, 2028, 2061 (above, made by Mitsui Chemicals) and Melan 522 (made by Hitachi Chemical Co., Ltd.).

  The blocked polyisocyanate compound is obtained by blocking an isocyanate group of a polyisocyanate having two or more free isocyanate groups in one molecule with a blocking agent. The blocked polyisocyanate compound is an addition reaction product of the polyisocyanate compound and the blocking agent in a stoichiometric amount. As the polyisocyanate compound used here, those conventionally known can be used. For example, tolylene diisocyanate, xylylene diisocyanate, phenylene diisocyanate, diphenylmethane-2,4′-diisocyanate, diphenylmethane-4 , 4′-diisocyanate (usually called “MDI”), crude MDI, bis (isocyanate methyl) cyclohexane, tetramethylene diisocyanate, hexamethylene diisocyanate, methylene diisocyanate, isophorone diisocyanate, aromatic, aliphatic or alicyclic polyisocyanates Compound; cyclized polymer of these polyisocyanate compounds, isocyanate biuret; ethylene glycol in excess of these polyisocyanate compounds Le, propylene glycol, may be mentioned trimethylolpropane, hexanetriol, terminal isocyanate-containing compounds obtained by reacting a low molecular weight active hydrogen-containing compounds such as castor oil and the like. These can be used alone or in combination of two or more.

  On the other hand, the blocking agent is added and blocked 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 When heated to about 200 ° C., it is desirable that the blocking agent dissociates and free isocyanate groups can be regenerated.

The thermosetting anion electrodeposition coating is appropriately selected and blended according to each purpose, such as an anionic resin, a crosslinking agent, a pigment, a pigment dispersant, an antifoaming agent, a plasticizer, an organic solvent, and a neutralizing agent. The solid content of the paint can be 5-30% by mass, preferably 10-25% by mass.
In the electrodeposition coating, a coating temperature is formed by adjusting the bath temperature to 15 to 40 ° C., preferably 20 to 35 ° C., and applying current for 1 to 10 minutes at a load voltage of 20 to 400 V, preferably 30 to 200 V. The film thickness of the coating film is not particularly limited, but in general, the dry film thickness can be in the range of 5 to 40 μm, preferably 10 to 30 μm. The baking curing temperature / time of the coating film is generally about 110 to about 220 ° C., preferably about 120 to about 170 ° C., and 5 to 120 minutes, preferably 10 to 50 minutes.

  Hereinafter, the present invention will be described in more detail with reference to examples. The present invention is not limited thereby. “Parts” and “%” indicate “parts by mass” and “% by mass”.

Production Example 1 Resole type phenolic resin solution No. 1 1 Production Example 1 In a four-necked flask, 100 parts of m-cresol, 37% formaldehyde aqueous solution 178
And 1 part of sodium hydroxide were added and reacted at 60 ° C. for 3 hours.
Dehydrated for hours. Subsequently, 100 parts of n-butanol and 3 parts of phosphoric acid were added and reacted at 110 to 120 ° C. for 2 hours. After completion of the reaction, the resulting solution was filtered to remove sodium phosphate, which was filtered to obtain a resol type phenol resin solution No. having a solid content of about 50%. 1 was obtained. The obtained resin had a number average molecular weight of 750.

Production Example 2 Resol type phenol resin solution No. Production Example 2 No. 2 A four-necked flask was charged with 188 parts of carboxylic acid and 324 parts of a 37% aqueous formaldehyde solution and heated to 50 ° C. to uniformly dissolve the contents. Next, zinc acetate was added and mixed to adjust the pH of the system to 5.0, and then heated to 90 ° C. and reacted for 5 hours. Then 5
After cooling to 0 ° C. and slowly adding a 32% calcium hydroxide aqueous dispersion to adjust the pH to 8.5, the reaction was carried out at 50 ° C. for 4 hours. After completion of the reaction, the pH was adjusted to 4.5 with 20% hydrochloric acid, and then the resin was extracted with a mixed solvent of xylene / n-butanol / cyclohexanone = 1/2/1 (mass ratio) to obtain catalyst, neutralization The salt was removed, followed by azeotropic dehydration under reduced pressure, and a resol type phenol resin solution No. having a solid content of about 60% was obtained. 2 was obtained. The obtained resin had a number average molecular weight of 320.

Production Example 3 Fatty Acid-Modified Acrylic Resin No. The following “Monomer (1)” in Production Example 1 was placed in a reaction vessel. The reaction was carried out at a temperature of 140 to 150 ° C. with stirring. The addition reaction of the epoxy group and the carboxyl group was followed while measuring the amount of the remaining carboxyl group, and the reaction was conducted after 4 hours. 1 was obtained.
Monomer (1)
Linseed oil fatty acid 236 parts
119 parts glycidyl methacrylate
Hydroquinone 0.4 parts
0.2 parts of tetraethylammonium bromide Next, 54 parts of ethylene glycol monobutyl ether was placed in a reaction vessel and heated to 120 ° C. While maintaining the temperature at 120 ° C., the mixture containing the content of the monomer (2) was dropped in about 2 hours.
Monomer (2)
30 parts of “Reactant No. 1” obtained by the above reaction
40 parts of styrene
15 parts of n-butyl methacrylate
2-ethylhexyl methacrylate 8 parts
Acrylic acid 7 parts
Azobisisobutyronitrile 3 parts
After completion of the dropwise addition, 1 part of azobisisobutyronitrile was added to the reaction vessel, and then the reaction was conducted for 3 hours while maintaining the temperature at 120 ° C. The acid value was 55 mg KOH / g and the fatty acid-modified acrylic resin No. 1 was obtained.

Production Example 4 Fatty acid-modified acrylic resin No. Production Example 2 54 parts of ethylene glycol monobutyl ether was placed in a reaction vessel and heated to 120 ° C. While maintaining the temperature at 120 ° C., the mixture containing the content of the monomer (3) was dropped in about 2 hours.
Monomer (3)
“Reactant No. 1” 10 parts similar to that used in Production Example 3
50 parts of styrene
20 parts of i-butyl methacrylate
2-hydroxyethyl methacrylate 10 parts
Acrylic acid 7 parts
γ-Methacryloyloxypropyltrimethoxysilane 3 parts
Azobisisobutyronitrile 5 parts
After completion of the dropwise addition, 1 part of azobisisobutyronitrile was added to the reaction vessel, and then the reaction was conducted for 3 hours while maintaining the temperature at 120 ° C. The acid value was 55 mg KOH / g and the fatty acid-modified acrylic resin No. 2 was obtained.

Production Example 5 Production Example of Epoxy Resin Modified / Fatty Acid Modified Acrylic Resin Fatty Acid Modified Acrylic Resin No. 1 Obtained in Production Example 3 1 is added with 1500 parts and Epicoat 1001 (trade name, epoxy resin, manufactured by Japan Epoxy Resin Co., Ltd.), heated to 120 ° C., reacted until the acid value becomes 48 mg KOH / g, and an epoxy having a solid content of 65% A resin-modified / fatty acid-modified acrylic resin was obtained.

Production Example 6 Emulsion No. Example 1
Fatty acid-modified acrylic resin No. 1 prepared in Production Example 3 138 parts (solid content 90 parts), ethylene glycol monobutyl ether 20 parts, benzyl alcohol 15 parts, resol type phenol resin solution No. 1 1 was mixed with 20 parts (solid content 10 parts), triethylamine 11.6 parts and deionized water 128.4 parts as a neutralizing agent with a disper. 1 was obtained.

Production Examples 7 to 13
Emulsion No. 5 was prepared in the same manner as in Production Example 6 except that the content of Table 1 was used. 2 to emulsion No. 2 8 was obtained.

Production Example 14 Pigment Dispersion Paste No. 1 Production Example 65% fatty acid-modified acrylic resin No. 1 obtained in Production Example 3 1 is 15.4 parts (10 parts solids), carbon black is 2 parts, talc is 4.5 parts, tripolyaluminum dihydrogen phosphate is 5.5 parts, neutralizing agent is 1.2 parts triethylamine, deionized water is 15.4. Part No. was added to a ball mill and stirred for 20 hours to obtain a pigment dispersion paste No. 50 having a solid content of 50%. 1 was obtained.

Production Example 15 Pigment Dispersion Paste No. Production Example 2 The 65% fatty acid-modified acrylic resin No. 1 obtained in Production Example 3 was used. No. 1 15.4 parts (solid content 10 parts), carbon black 2 parts, talc 4.5 parts, rust inhibitor No. 1 1 (Note 3) 5.5 parts, 1.2 parts of triethylamine as a neutralizing agent and 15.4 parts of deionized water were added to a ball mill and stirred for 20 hours to obtain a pigment dispersion paste No. 50% solid content. . 2 was obtained.
(Note 3) Rust preventive agent No. Was _{1: 2MgHPO 4 · 3H 2 O · 2SiO} 2 · CaSiO 3 · 2CaCO 3.

  The above-mentioned pigment dispersion paste No. 1 and pigment dispersion paste No. 1 Table 2 shows the content of the blending of 2.

Example 1
Emulsion No. 1 to 333 parts (solid content 100 parts) pigment dispersion paste No. 1 44 parts (solid content 22 parts) were added, 436 parts of deionized water was further added and stirred, and the electrodeposition paint No. 1 having a solid content of 15% was added. 1 was obtained.

Examples 2-7
In the same manner as in Example 1, the electrodeposition paint Nos. 2-No. 7 was obtained.

Comparative Examples 1-3
In the same manner as in Example 1, the electrodeposition paint Nos. 8-No. 10 was obtained.

Coating test The electrodeposition paint No. obtained in Examples and Comparative Examples above. 1-No. 10 was immersed in a cold-rolled dull steel plate whose surface was degreased using an organic solvent, and this was used as an anode for electrodeposition coating.
After forming a dry film thickness of 20 μm, the film was washed with water, forcedly dried at 80 ° C. for 30 minutes, and dried at room temperature for 7 days.

  Table 3 shows the contents of the examples and the coating film performance. Table 4 shows the content of the comparative example and the coating film performance. The performance test was performed according to the following test method.

(Note 4) Paint stability: Sealed and stirred at 30 ° C. for 4 weeks, and 3 L of bath paint was filtered through a 400 mesh filter.
A: The filtration residue is less than 5 mg / L. O: The filtration residue is less than 10 mg / L. Δ: The filtration residue is 10 mg / L or more and less than 20 mg / L. X: The filtration residue is 20 mg / L or more.
(Note 5) Non-tackiness of coating film: The tackiness of the coating surface was evaluated by touch.
◎: Not sticky and does not stick to scratch (after nail) 〇: Not sticky, but scratch (after fingernail) is attached but there is no problem as a product △: Sticky but does not leave fingerprint mark × : Sticky and has fingerprint marks.

  (Note 6) Pencil hardness: In accordance with JIS K 5600-5-4, apply a pencil lead at an angle of about 45 degrees to the test coating plate surface, and push forward against the test coating plate surface to the extent that the core does not break. It moved about 10 mm at a uniform speed. The hardness symbol of the hardest pencil when this operation was repeated 5 times while changing the test location and the coating film was not torn was defined as pencil hardness.

(Note 7) Coating film adhesion: The appearance of the coated surface was evaluated.
○: Smoothness is good and there is no problem.
Δ: Slightly decreased finishes such as swells, glossy skins, and chili skins x: Slightly reduced finishes such as swells, glossy skins, and chili skins.

(Note 8) 60 degree specular gloss:
See Note 2.

(Note 9) Salt spray resistance: Each electrodeposition coating plate obtained was subjected to cross-cut scratches with a knife so as to reach the substrate, and this was sprayed with salt water for 120 hours according to JIS Z-2371. The test was conducted and evaluated by the following criteria based on the rust and blister width from the knife scratch. ◎: The maximum width of rust and blister was less than 2 mm from the cut part (one side)
○: The maximum width of rust and blisters is 2 mm or more and less than 3 mm from the cut part (one side)
Δ: The maximum width of rust and blisters is 3 mm or more from the cut part and less than 4 mm (one side)
X: The maximum width of rust and blisters is 4 mm or more from the cut part

Even if it does not contain harmful metals such as lead and chromium, a coated article excellent in non-adhesiveness, curability, finish, and corrosion resistance can be obtained.

Claims (5)

An anionic electrodeposition paint containing 1 to 30 parts by mass of the resol type phenol resin (A) with respect to 100 parts by mass of the solid content of the base resin. The anion electrodeposition coating material of Claim 1 containing a fatty-acid modified acrylic resin (B) as base resin. The fatty acid-modified acrylic resin (B) contains 0.1 to 10% by mass of an alkoxysilyl group-containing polymerizable unsaturated monomer based on the total solid content of the mixture of radical polymerizable unsaturated monomers, and alkoxysilyl The anionic electrodeposition paint according to claim 1 or 2, which is a fatty acid-modified acrylic resin obtained by reacting a group-containing polymerizable unsaturated monomer. The anion battery according to any one of claims 1 to 3, comprising an epoxy resin-modified / fatty acid-modified acrylic resin (C) obtained by reacting a fatty acid-modified acrylic resin (B) and an epoxy resin as a base resin. Wearing paint. The coated article obtained by carrying out electrodeposition coating using the anion electrodeposition coating material of any one of Claims 1-4.