JPH08225994A - Formation of metal surface treatment coating film - Google Patents

Abstract

PURPOSE: To form a good painting undercoat consisting of a uniform coating film even on a non-platelike metallic product by immersing a metal in an aq. solution of an aqueous coating composition that contains a resin having phosphate groups and subjecting the metal to anodic treatment under specified conditions. CONSTITUTION: In this formation, a metal is immersed in an aq. solution or dispersion of an aqueous coating composition contg. a resin that has phosphate or phosphonate groups and also preferably phenol or bisphenol segments. As the composition, e.g. a composition which contains 100 pts.wt. of the solid content of this resin and 10 to 500 pts.wt. of at least one resin selected from aqueous phenol resins, polyurethane emulsions and resins having functional groups each reactive with a hydroxyl or carboxyl group is preferred. Then, the metal immersed in the aq. solution or the like is subjected to anodic treatment under the conditions of 1 to 20V of the electrolytic voltage, 0.04 to 0.45 V/sec of the voltage rising rate and 10sec to 3min of the treating time to form a coating film of the aqueous composition on the surface of the metal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a metal surface treatment film for surface treatment of household appliances such as electric refrigerators, metal products such as cans and wheels, and metals used for automobiles.

[0002]

2. Description of the Related Art Cold rolled steel sheets, zinc-based plated steel sheets, aluminum-based alloy-plated steel sheets, etc. are widely used for building materials, household appliances, automobiles and the like. These steel plates and the like are usually subjected to a surface treatment that becomes a coating base after the forming process,
Used for painting before assembly processing. Sludge is inevitably generated in the zinc phosphate treatment (hereinafter referred to as "chemical conversion treatment") used as a coating base on the surface of such a steel sheet. In recent years, due to increasing concern about environmental problems, waste problems, etc., the cost of disposing sludge by-produced in the chemical conversion treatment process has increased, so there has been a demand for sludge-less conversion during chemical conversion treatment. Further, from the viewpoint of cost reduction, not only the sludge disposal cost, but also the maintenance cost required for sludge treatment such as separation and coagulation sedimentation, the problem of space saving resulting from the need for a large space for chemical conversion treatment, pH, In view of the complexity of control of the chemical conversion treatment line liquid such as acidity, there has been a strong demand for an alternative surface treatment method to the chemical conversion reaction type zinc phosphate treatment.

Coating-type chromate treatment and reactive-type chromate treatment have been put to practical use as coating surface treatments instead of zinc phosphate treatment. According to these treatments, proper surface treatment such as corrosion resistance and adhesion, and space saving of treatment process are realized. The above problems such as sex are solved. However, since hexavalent chromium is used in the above chromate treatment, there is a problem that the treatment waste liquid is discharged from the standpoint of occupational hygiene, working environment, environmental protection, etc. .

Various non-chromium type treating agents which do not use hexavalent chromium have been proposed. However, when they are used as a coating base for carbon steel and galvanized steel, the corrosion resistance deteriorates. It is applied only to specific fields such as post-treatment of treatments, treatment of aluminum cans and the like.

Therefore, it has a function as an aqueous coating composition for a coating type undercoat which can improve the space property by eliminating the sludge treatment and the waste liquid treatment related to the zinc phosphate treatment,
Moreover, it is necessary to find a composition that can maintain corrosion resistance even without chromate treatment on galvanization, and at the same time, can realize a function as a lubricating anticorrosion coating composition that imparts lubricity and a lubricating anticorrosion coating composition for automobiles. Consideration was made. As a result, for example, a resin containing a phosphoric acid group, and an aqueous coating composition containing an oxazoline compound, a phenol resin, a melamine resin and the like and an acidic catalyst added thereto have been proposed. The coating-type anticorrosive coating composition based on such an aqueous coating composition was able to sufficiently exhibit its function in the anticorrosive treatment for the coating base such as steel plate and galvanized steel plate.
Also, when used for lubrication and rust prevention treatment of galvanized steel sheet,
Sufficient corrosion resistance was ensured regardless of the presence or absence of chromate treatment.

[0006]

When a metal is rust-proofed using the above aqueous coating composition, the above-mentioned water-based coating is applied to the one which becomes a flat plate when applied, such as a coil-shaped or plate-shaped steel sheet. It was sufficiently possible to apply the coating composition with a roll and to carry out a rust preventive treatment. However, for example, steel desks, steel rockers, parts after press molding, cast products, etc., and block-shaped metal products, such as engine blocks, etc., have complicated surface shapes, so the above aqueous coating composition It was impossible to apply the product by a roll coating method to perform rust prevention treatment.
Furthermore, when the above aqueous coating composition is applied to a steel sheet or the like by a method such as ordinary spraying, showering, dipping, etc., the sagging after the application of the applied aqueous coating composition causes a drooping pattern of the base on the top coating surface. And the appearance is poor, and film thickness unevenness occurs between the top and bottom of the object to be coated and between the inner and outer surfaces. Therefore, the corrosion resistance decreases in the thin part of the coating film, and peeling due to distortion occurs in the thick part of the coating film. There was an inconvenience. Furthermore, in the case of the above-mentioned metal products and the like, when such a method is used, liquid tampering occurs in the convex corners and the like of the metal molded product, and the occurrence of blisters and corrosion resistance in such parts. As a result, it is difficult to form a good coating base on the metal.

On the other hand, as a method for uniformly forming a coating film of a coating composition on a metal surface having irregularities, there is an electrodeposition coating method. The electrodeposition coating method involves forming a resin coating film on an object by placing an electrically conductive object in a paint dispersed in water and passing an electric current so that the object and another metal object have both polarities. However, unless a high voltage of 50 to 500 V is applied and a film thickness of 10 to 30 μm is usually applied, a smooth coating film having corrosion resistance cannot be formed, and a thin film preferable as a coating base can be formed. It was difficult.

In view of the above situation, the present invention is capable of forming a uniform film even in a non-planar metal product by using an aqueous coating composition, and forming a metal surface-treated film which forms a good coating base. It is intended to provide a method.

[0009]

The gist of the present invention is to provide a method for forming a film of an aqueous coating composition on the surface of a metal, wherein the aqueous coating composition is at least one of a phosphoric acid group and a phosphonic acid group. Is a coating composition comprising a resin having, after immersing the metal in an aqueous solution or dispersion of the aqueous coating composition,
Electrolytic voltage 1 to 20 V, voltage boosting rate 0.04 to 0.45
The metal is subjected to anodic electrolytic treatment under the conditions of V / sec and treatment time of 10 seconds to 3 minutes. The present invention is described in detail below.

In the present invention, an aqueous solution or dispersion of a coating composition (hereinafter referred to as "coating composition I") containing a resin having at least one of a phosphoric acid group and a phosphonic acid group is used as a bath liquid. To use as. The resin having at least one of the phosphoric acid group and the phosphonic acid group has a phosphoric acid group or a phosphonic acid group as a functional group. The resin having at least one of the phosphoric acid group and the phosphonic acid group used in the present invention is
It contains a phosphoric acid group or a phosphonic acid group having a non-esterified hydroxyl group. When all of the phosphoric acid groups and phosphonic acid groups in the resin are esterified, the emulsifying property of the resin decreases when it is emulsified and suspended in water by neutralization with amine or ammonia, and metal During the anode electrolytic treatment, the eluted metal is less likely to react with these groups, so that a corrosion-resistant film is not formed.

The resin having at least one of the phosphoric acid group and the phosphonic acid group used in the present invention preferably has an acid value of 5.0 to 50 based on the phosphoric acid group and the phosphonic acid group. When the acid value based on the phosphoric acid group and the phosphonic acid group is less than 5.0, the water emulsifying property is lowered, and a film is hard to be formed when the metal is subjected to the anode electrolysis treatment. The group remains to reduce the water resistance. More preferably, it is 10-35.

The resin having at least one of the phosphoric acid group and the phosphonic acid group used in the present invention is
It is not particularly limited as long as it has a phosphoric acid group or a phosphonic acid group as a functional group, and for example, an acrylic type, a polyester type condensed with a polyhydric alcohol and a polybasic acid, or a fatty acid Examples thereof include condensed polyester-based ones and polyurethane-based ones in which a polyol is bound by an isocyanate, but those having a phenol or bisphenol segment are preferable from the viewpoint of corrosion resistance, and above all, a bisphenol-type epoxy resin. The phosphoric acid modified product of can be preferably used.

The phosphoric acid modified product of the bisphenol type epoxy resin has an acid value of 5 to 35 due to the phosphoric acid group. In the phosphoric acid-modified product of the bisphenol type epoxy resin, when the acid value is other than phosphoric acid such as a carboxylic acid compound, it is weak against peeling occurring at the cathode part when corrosion occurs, At least 5
35 is not preferable unless it is a phosphate group.

Even among the above bisphenol type epoxy resins modified with phosphoric acid, phosphoric acid esters are not preferable. For example, JP-A-5-320566
JP-A-5-320569 and the like disclose that a bisphenol type epoxy resin is added with a phosphoric acid ester instead of phosphoric acid, and is modified with a carboxyl group-containing resin so as to have emulsifying property. However, even after the cured film is formed, the carboxyl group remains without disappearing, and therefore, in a film that requires high corrosion resistance and high wet adhesion, water resistance is high. Is deteriorated and causes a peeling of the coating film when used as a coating base, and therefore cannot be used in the present invention.

The weight average molecular weight of the phosphoric acid modified product of the bisphenol type epoxy resin is preferably 3,000 to 20,000. If it is less than 3,000, the corrosion resistance and wet adhesion are poor, and if it exceeds 20,000, the coating composition tends to thicken, the uniformity of the coating tends to deteriorate, and the amount of coating to be coated tends to decrease, such being undesirable.

Examples of phosphoric acid modified products of the above bisphenol type epoxy resin include XQ-82294.00,
XQ-82294.01 (acid value 35, weight average molecular weight 3
000, manufactured by Dow Chemical Japan), XQR-711
-1352.61 (acid value 22, weight average molecular weight 500)
0, manufactured by Dow Chemical Japan), XU-8096.0.
7 (acid value 12, weight average molecular weight 10000, manufactured by Dow Chemical Japan), XQR-711-1352.60
(Acid value 12, weight average molecular weight 10,000, manufactured by Dow Chemical Japan), XU-71899.00 (acid value 10,
A weight average molecular weight of 16000, manufactured by Dow Chemical Japan Co., Ltd.) is preferably neutralized with amine or ammonia, and the emulsion liquid after emulsification is adjusted to have a pH of 6.0 to 9.0.

Coating composition I used in the present invention
Is at least 1 of the above phosphoric acid group and phosphonic acid group.
In addition to the resin having seeds, an aqueous phenolic resin,
At least one selected from the group consisting of a polyurethane resin emulsion, a resin having a functional group capable of reacting with a hydroxyl group, and a resin having a functional group capable of reacting with a carboxyl group.
Seeds can be included. Hereinafter, this is referred to as "coating composition II".

The aqueous phenolic resin is not particularly limited as long as it is an aqueous phenolic resin, for example, an acid value of 1
Resin composition obtained by pre-condensing at least one of 00 to 500 acrylic resin and epoxy resin and at least one of resol-type phenol resin and amino resin and dispersing in a volatile base aqueous solution; phenolic 20-80% of the hydroxyl groups are allyl etherified, a weight average molecular weight of 250-800, and a low molecular weight component of 10% by weight or less, an allyl ether type phenol resin, an acrylic resin and an epoxy resin containing a carboxyl group. A resin composition obtained by dispersing a resin and an aqueous medium in the presence of an amine; Shownol B manufactured by Showa High Polymer Co., Ltd.
Highly water-soluble resol type phenolic resin such as RL-125S, 126A; Shonor BRL-117, 134, 1
583, 230C, 273Z, 276O, 280Z, 2
04, 219, 1251, 2534, 113, 116,
Examples thereof include water-soluble resol type phenolic resins such as 120Z and 112A; aqueous emulsions such as BRE-174 and N-2.

The polyurethane resin emulsion may be either a forced emulsification type that uses an emulsifier or a self-emulsification type that does not use an emulsifier. In the present invention, a self-emulsifying type polyurethane resin emulsion is preferable because it does not cause a problem such as a change in film strength and a decrease in water resistance due to the remaining emulsifier. Self-emulsifying type polyurethane resin emulsion has a gel structure,
It is also preferable for the present invention in that the hydration stability of the emulsion is good.

As the polyurethane resin emulsion, various types such as polyether type, polyester type, polycarbonate type and mixed type thereof can be used depending on the kind of raw material. Examples of the polyether-based polyurethane resin emulsions include Superflex 110 (Daiichi Kogyo Seiyaku Co., Ltd.), Superflex F-8438D (Daiichi Kogyo Seiyaku Co., Ltd.) and Hydran HW950 (Dainippon Ink and Chemicals Co., Ltd.). Etc. can be mentioned.

Examples of the above polyester-based polyurethane resin emulsion include Superflex F-
8123D (Daiichi Kogyo Seiyaku Co., Ltd.), Hydran HW91
0 (manufactured by Dainippon Ink and Chemicals), Hydran HW92
0 (manufactured by Dainippon Ink and Chemicals), Hydran HW93
0 (manufactured by Dainippon Ink and Chemicals, Inc.), Hydran HW94
0 (manufactured by Dainippon Ink and Chemicals, Inc.), Hydran HW96
0 (manufactured by Dainippon Ink and Chemicals, Inc.) and the like can be mentioned. Examples of the polycarbonate-based polyurethane resin emulsion include Superflex 460
(Manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), Superflex F-812
4D (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), Hydran HW935 (manufactured by Dainippon Ink and Chemicals, Inc.), Hydran HW980 (manufactured by Dainippon Ink and Chemicals, Inc.) and the like can be mentioned. These can be used in combination of two or more.

The polyurethane resin emulsion preferably has a glass transition temperature (hereinafter referred to as "Tg") of 10 to 80 ° C. When the Tg is within this range, when the coating composition used in the present invention is formed into a film, desired film strength and adhesion can be obtained in a wide temperature range of 130 to 180 ° C. More preferably, 20-8
0 ° C. In the present invention, the desired Tg can be obtained by mixing the above various polyurethane resin emulsions.
Can be obtained.

The resin having a functional group capable of reacting with the hydroxyl group and the resin having a functional group capable of reacting with the carboxyl group are at least one of the phosphoric acid group and the phosphonic acid group.
It reacts with each of the hydroxyl group and the carboxyl group in the seed-containing resin, the aqueous phenolic resin or the polyurethane resin emulsion. The resin having a functional group that reacts with the hydroxyl group has a curing start temperature of 140
Melamine resins having a temperature of ℃ or less are preferred. If the curing start temperature is higher than 140 ° C., the degree of curing of the film will be insufficient by baking at a low temperature for a short time. Among them, those having a high curing speed are preferable.

In the present specification, the "curing start temperature" means the temperature rise rate of 3 ° C./min by DSA (dynamic spring analysis method) and E
It represents the value measured by reading from the inflection point of the curve in which r (relative dynamic elastic modulus) is plotted. The resin used at this time is an alkyd resin having an acid value of 39 and a hydroxyl value of 140, and the catalyst used is a naphthalenesulfonic acid-based acidic catalyst. When measuring the melamine resin, the alkyd resin and the melamine resin are mixed in a solid content ratio of 7: 3, and the catalyst is used in an amount of 2 parts by weight based on 100 parts by weight of the solid content of the mixture of the alkyd resin and the melamine resin. Compound.

The melamine resin is preferably an imino- or methylol-modified or mixed-modified melamine resin. Butoxy-modified melamine resin is not preferable because it is inferior in uniform mixing property with a water-soluble resin and the stability of the coating composition is reduced.

As the melamine resin satisfying the above conditions, for example, imino type melamine resins such as Cymel 327 and Cymel 328 (manufactured by Mitsui Cytec); Cymel 370.
(Mitsui Cytec Co., Ltd.) and the like, methylol-modified melamine resins, and mixed-modified melamine resins thereof and the like.

Examples of the resin having a functional group which reacts with the carboxyl group include oxazoline compounds. This is effective when the resin having at least one of the phosphoric acid group and the phosphonic acid group, the aqueous phenol resin or the polyurethane resin emulsion contains a carboxyl group.

The oxazoline compound has the structure of the following general formula [1]. The oxazoline compound easily reacts with a compound having a carboxyl group to cause the following ring-opening addition reaction.

[0029]

Embedded image

In the formula, R and R'represent various polymers. In the present invention, R is preferably a styrene-based polymer or an acrylic-styrene-based copolymer from the viewpoint of imparting toughness to the film and increasing Tg. The oxazoline compound is not particularly limited, and examples thereof include Epocros K-1010E and Epocros K-1020 manufactured by Nippon Shokubai Co., Ltd.
E, Epocros K-1030E, Epocros K-105
Among them, Epocros K-1030E and Epocros K-1050E are preferable because they have a high Tg and give a tough and highly adhesive film.
Also, Epocros K-1010E, Epocros K-10
Even with 20E, the addition amount, the curing temperature, and the catalyst can be adjusted and used so that the coating film to be formed is a desired film.

The oxazoline compound preferably has a Tg of 0 ° C. or higher. If the temperature is lower than 0 ° C, a film excellent in adhesiveness to a steel sheet and curing degree cannot be obtained under baking conditions of low temperature and short time (about 150 seconds at 150 ° C).

When the melamine resin and the oxazoline compound are used in combination, the melamine resin and the oxazoline compound are contained in a resin having at least one of the phosphoric acid group and the phosphonic acid group, an aqueous phenol resin or a polyurethane resin emulsion. It is possible to form a coating film that is firmly adhered by reacting and curing with the respective hydroxyl group and carboxyl group.

Coating composition I used in the present invention
In I, the content of at least one selected from the group consisting of the above aqueous phenolic resin, polyurethane resin emulsion, resin having a functional group capable of reacting with a hydroxyl group, and resin having a functional group capable of reacting with a carboxyl group is At least one of the above phosphoric acid group and phosphonic acid group
It is 10 to 500 parts by weight in terms of solid content with respect to 100 parts by weight of the resin solid content containing seeds. When the content is less than 10 parts by weight, poor curing, poor adhesion, and poor water resistance occur. For example, when the content of the aqueous phenolic resin is low,
The adhesiveness to the metal substrate is reduced, and the self-condensation effect of the metal substrate is reduced, so that the curability with time after drying under forced drying conditions of about 60 to 80 ° C. is reduced, and the polyurethane resin emulsion When the content is too small, the adhesion to the metal base or the topcoat is lowered, and as a result, the adhesion of the topcoat particularly when overbaked is lowered. Further, if the content of the resin having a functional group that reacts with a hydroxyl group is small, curing failure occurs, and if the content of a resin having a functional group that reacts with a carboxyl group is small, the amount of residual carboxyl groups increases even after baking. , The water resistance is reduced. When the content exceeds 500 parts by weight, these resins remain unreacted, which causes softening of the cured film, lowering of glass transition temperature, lowering of adhesion, lowering of water corrosion resistance and the like. It is preferably 10 to 200 parts by weight.

In the present invention, when forming the metal surface treatment film, the metal is subjected to anodic electrolytic treatment in a bath prepared by diluting the above coating composition I or coating composition II with water to form a thin film. The electrolysis voltage of the above-mentioned anode electrolysis treatment is 1 to 20V. If the electrolysis voltage is less than 1V, less film will be formed and the corrosion resistance will be worse.
If it exceeds the range, a defect called rupture occurs in the electrodeposited resin film, the corrosion resistance is deteriorated, and the finish appearance of the topcoat is adversely affected. Therefore, it is limited to the above range. It is preferably 3 to 10 V.

The voltage boosting rate in the above-mentioned anode electrolysis treatment is
It is 0.04 to 0.45 V / sec. The voltage boost rate is 0.
If it is less than 04 V / sec, the dissolution rate of the metal becomes slow, and the amount of metal ions reacting with the phosphoric acid group and the phosphonic acid group during the anode electrolysis treatment is small, resulting in insufficient adhesion of the film, resulting in 0.45 V / If it exceeds the second, the amount of electrodeposition of the resin will increase, and a porous film will be formed as compared with the case where the same composition is coated by a bar coater or the like. Therefore, a film thickness of at least about 6 μm is required to secure corrosion resistance. Since it is not suitable as a coating base, it is limited to the above range. Preferably 0.
It is 08 to 0.40 V / sec.

The voltage application in the above-mentioned anode electrolysis is not limited to the method of continuing at a predetermined voltage boosting rate until reaching a predetermined ultimate electrolytic voltage, but after reaching a predetermined ultimate electrolytic voltage at a predetermined voltage boosting rate, It is also possible to use a method in which the electrolysis voltage is maintained for a certain period of time.

The processing time for the anode electrolysis is 10
Seconds to 3 minutes. If the treatment time is less than 10 seconds, the film formation is small and the corrosion resistance is poor, and it is difficult to control the electrolytic treatment. If the treatment time is more than 3 minutes, the film thickness becomes large, making it unsuitable as a coating base. However, since the electrolytic treatment zone becomes long, which is inconvenient, it is limited to the above range. It is preferably 10 seconds to 2 minutes.

The above-mentioned anode electrolysis treatment in the present invention comprises
Normal anion electrodeposition uses a high voltage of about 50 to 500 V, and as compared with the fact that the voltage boosting rate is also relatively slow, as described above, a low electrolysis voltage of 1 to 20 V is used,
In an aqueous solution or an aqueous dispersion of a coating composition containing a resin having at least one of a phosphoric acid group and a phosphonic acid group under electrolytic treatment conditions with a large voltage boosting rate of 0.04 V / sec or more. Is done in.

It is known to carry out anion electrodeposition in an aqueous dispersion of a coating composition, for example, JP-A-58-79010 and JP-A-62-74968.
Japanese Patent Laid-Open No. 11-67575 and the like disclose that the coating composition is electrodeposited. However, JP-A-58-79010 and JP-A-1-11
Japanese Patent Laid-Open No. 675/1987 does not disclose electrodeposition conditions.
In Japanese Patent Publication No. 74968-8, a much higher electrodeposition voltage is used than in the present invention, and the above-mentioned anode electrolysis treatment in the present invention uses treatment conditions different from those of ordinary anion electrodeposition.

Further, in the present invention, the anode electrolysis treatment forms not only the electrodeposition resin film but also the composite film of the resin and the metal phosphate. At this time, the above-mentioned anodic electrolytic treatment conditions enable the formation of a metal phosphate film with a small amount of reaction of metal.

The thickness of the thin film formed by the anode electrolysis treatment in the present invention is preferably 0.1 to 10 μm. If it is less than 0.1 μm, the corrosion resistance is poor, and if it exceeds 10 μm, rupture occurs and the appearance is deteriorated.
Processing time becomes long. The thickness is more preferably 0.2 to 6 μm, still more preferably 0.2 to 3 μm. By setting the conditions of the anode electrolytic treatment within the above range, it is possible to form a thin film having excellent corrosion resistance even when the thickness is 3 μm or less, and it is possible to form a coating base film having excellent corrosion resistance.

In the present invention, the metal to be subjected to the above-mentioned anode electrolysis treatment is not particularly limited. For example, carbon steel, various alloy steels including stainless steel, iron such as cast iron; zinc, zinc / nickel, zinc / Zinc or zinc-based alloys such as aluminum, zinc / tin, zinc / lead, zinc / iron, zinc / cobalt; galvanized steel by various plating methods such as electroplating or hot dipping of zinc or zinc-based alloys; aluminum, aluminum / zinc Aluminum alloys such as; aluminum or aluminum alloy plated steel, and the like; further, plated steel with tin, copper, nickel, lead, or lead-based alloys; reactive chromate treatment, coating type on steel plate or galvanized steel plate Examples thereof include surface-treated steel plates that have undergone metal surface treatment such as chromate treatment and chemical conversion treatment. Of these, steel, zinc or a zinc-based alloy, zinc or a zinc-based alloy plated steel, aluminum or an aluminum alloy, and aluminum or an aluminum alloy plated steel can be preferably used. Further, these metals may have various shapes such as a plate shape, a block shape, a cylinder shape, a can, a sash, and a wheel.

Coating composition I used in the present invention
Alternatively, the coating composition II contains a benzenesulfonic acid derivative, an amine salt and an ammonium salt thereof, a naphthalenesulfonic acid derivative, for the purpose of quick curing at a low temperature.
An amine salt and an ammonium salt thereof, an acidic phosphoric acid amine salt and an ammonium salt, and a phosphonic acid derivative,
An acidic catalyst composed of at least one selected from the group consisting of the amine salt and the ammonium salt can be blended. Hereinafter, a coating composition I mixed with the above acidic catalyst or a coating composition II mixed with the above acidic catalyst will be referred to as "coating composition II".
I ".

Amines and ammonium are preferable as the cations forming the salt of the above-mentioned acidic catalyst, because they are volatilized during the heat curing of the coating and hardly remain in the coating. Alkali metals and metal cations are not preferable because they are ionized in the paint and remain in the coating film, causing absorption of water. Examples of the acidic catalyst include dodecylbenzene sulfonic acid, dinonylnaphthalene sulfonic acid, ammonium dihydrogen phosphate, ammonium monohydrogen phosphate, Catalyst 5
00 (Mitsui Cytec), Catalyst 600
(Same), Catalyst 4040 (Same), and the like.

Among the above acidic catalysts, the acidic phosphoric acid may be an inorganic phosphate such as ammonium dihydrogen phosphate, ammonium monohydrogen phosphate or the like, or a phosphoric acid group bonded to a resin. For example, it may be a phosphoric acid-modified product of polyvinyl alcohol or a phosphoric acid-modified product of the above bisphenol type epoxy resin. When these are used, the low molecular weight acidic catalyst may not be added or only a very small amount may be added. As the acidic phosphoric acid, polyvalent phosphoric acid such as phytic acid may be used. In this case, this substance itself has a rust preventive function in addition to the catalytic function, and can enhance the anticorrosion property.

Of the above acidic catalysts, phosphonic acid derivatives,
The amine salt or ammonium salt thereof is not a phosphoric acid ester but a carbon atom and a phosphorus atom directly bonded to each other. The above-mentioned phosphonic acid is preferable for the purpose of the present invention because its structure is less likely to be hydrolyzed than the phosphoric acid ester.

The phosphonic acid derivative can enhance the rust preventive property. Examples of the phosphonic acid derivative, its amine salt or its ammonium salt include, for example, Dayquest 2000, Dayquest 2010, Dayquest 2
Examples include 041 (manufactured by Nippon Monsanto Co., Ltd.) neutralized with amine or ammonia.

The acidic catalyst is added in an amount of 0.1 to 5 parts by weight in terms of solid content, relative to 100 parts by weight of the coating composition I or coating composition II solid content. 0.
If it is less than 1 part by weight, the catalytic action will be lowered, and curing for a short time or at low temperature will be difficult. If it exceeds 5 parts by weight, the amount remaining in the coating film will be large and the water resistance will be lowered, such being undesirable.

In the present invention, the coating composition I, the coating composition II or the coating composition III may be rust-prevented, coated undercoat, lubricated rust-preventive coating, or may be further added with appropriate additives. It can be used to form anticorrosion coatings for automobiles.

When it is used for the above-mentioned rust prevention and formation of a coating base film, the above-mentioned coating composition I, coating composition II or coating composition III may be used in addition to 100 parts by weight of the solid content of the composition. At least one of rust pigment and fine particle silica may be appropriately contained.
It is preferable that the rust preventive pigment has an electric conductivity of 600 μS / cm or less in an aqueous dispersion prepared by dispersing 1 g in 100 g of deionized water. At least one of the rust preventive pigment and the fine particle silica is the coating composition I,
Coating composition II or coating composition III
1 to 40 parts by weight in terms of solid content is added to 100 parts by weight of solid content. If it is less than 1 part by weight, the corrosion resistance is lowered and 4
If it exceeds 0 parts by weight, the effect is saturated in corrosion resistance and the strength and water permeability of the coating are lowered.

Examples of the above-mentioned rust preventive pigments include calcium phosphate (eg, LF Bosei CP-Z manufactured by Kikuchi Dye Company),
Phosphate rust preventive pigments such as zinc phosphate; Molybdate rust preventive pigments such as zinc molybdate (eg, LF Bosei M-PSN manufactured by Kikuchi Dye Co., Mori White 101 manufactured by Honjo Chemical Co.); cyanamide zinc calcium (For example, LF Bosei ZK-S2 manufactured by Kikuchi Dye Co., Ltd.) and the like can be mentioned. From the viewpoint of stability of the aqueous dispersion, it is preferable that the particle diameter of the rust preventive pigment is small.

Examples of rust preventive pigments having an electric conductivity of more than 600 μS / cm include calcium leadate, silica phosphate,
There are zinc chromate, strontium chromate, barium metaborate, etc., but these not only impair the water resistance and blister resistance of the coating film, but also impair the stability of the water-soluble resin, so they are used in the present invention. I can't. In addition, lead-based rust preventive pigments such as basic lead sulfate and cyanamide lead cannot be used in the present invention except for special cases, from the viewpoint of toxicity.

As the above-mentioned silica, it is possible to use fine particles or colloidal silica such as sol, which is generally used as a coating agent for anticorrosive paints, especially for thin film type anticorrosive steel sheets, and its water dispersion. PH of liquid is 4-9
The dry silica, colloidal silica and the like are preferable. Since most of dry silica has an isoacid point in an acidic region of pH 4 to 5, it tries to lower the pH of the resin aqueous solution, and therefore the resin does not become water-soluble (becomes a dispersion type). When the coating composition used in the invention is set to be weakly alkaline, its storage stability becomes poor, which is not preferable. However, this is not the case when the coating composition used in the present invention is set to be weakly acidic.

Examples of the above-mentioned wet silica include those stabilized in water in a colloidal state. For example, Snowtex O (manufactured by Nissan Chemical Industries, Ltd.), Snowtex N (the same), Adelite AT-20 ( Asahi Denka Kogyo Co., Ltd.),
Adelite AT-30 (same), Adelite AT-40
(Same), Adelite AT-50 (Same), Adelite AT
-20S (same), Adelite AT-30S (same), Adelite AT-20N (same), Adelite AT-20A
(The same), Adelite AT-30A (the same) and the like. Further, examples of the above-mentioned dry silica include those referred to as fumed silica or vapor phase silica, and examples thereof include Aerosil 380 (manufactured by Nippon Aerosil Co., Ltd.), Aerosil 300 (the same), and Aerosil 200.
(The same) can be mentioned.

The silica used in addition to the coating composition used in the present invention is preferably colloidalized with a phosphoric acid compound, a molybdenum compound, a boric acid compound or the like. It is preferable that the colloidal particles contain silica and aluminum silicate as main components, and that these particles have high purity and do not contain miscellaneous ions. Examples of the dry aluminum silicate include Aerosil M
OX170 (manufactured by Nippon Aerosil Co., Ltd.), Aerosil MOX
80 (same), Aerosil COK84 (same) and the like. Aluminum silicate or the like can be more efficiently colloidalized than silica alone.

The content of the above-mentioned dry silica or dry aluminum silicate is preferably 1 to 40 parts by weight based on 100 parts by weight of the total amount including water. If the amount is less than 1 part by weight, the resulting colloidalized particles are likely to cause reaggregation, and the corrosion resistance of the film formed by the coating composition containing the colloidalized particles used in the present invention is lowered. If it exceeds 40 parts by weight, the corrosion resistance of the formed film tends to decrease. More preferably 5 to 20
Parts by weight, more preferably 10 to 15 parts by weight.

The colloidalization aid, which is the main component of the colloidal particles, may be any compound capable of forming a large anion in an aqueous solution, and may be a phosphoric acid compound such as pyrophosphoric acid, tripolyphosphoric acid or tetrapolyphosphoric acid. Condensed phosphoric acid such as acid, pentapolyphosphoric acid, hexapolyphosphoric acid, heptapolyphosphoric acid, octapolyphosphoric acid, nonapolyphosphoric acid, decapolyphosphoric acid, metaphosphoric acid, trimetaphosphoric acid, hexametaphosphoric acid, ultrapolyphosphoric acid and the like. An ammonium salt etc. can be mentioned.

Although there are alkali metal salts and alkaline earth metal salts of the above-mentioned phosphoric acid compounds, contamination with metal ions is a film formed by the coating composition used in the present invention which uses the obtained colloidalized particles. Adversely affect the corrosion resistance of. That is, if the coating contains metal ions, it accelerates the permeation of halogen ions (for example, Cl ⁻ ) through the film in a corrosive atmosphere, and also kills the cation exchange capacity of silica, resulting in extremely low corrosion resistance. Therefore, the use of alkali metal salts or alkaline earth metal salts is not preferred.

In addition to the above phosphoric acid compounds, molybdic acid compounds such as ammonium molybdate tetrahydrate; boric acid compounds such as ammonium pentaborate and metaboric acid; silicic acid compounds such as orthosilicic acid and meta Examples thereof include silicic acid. However, although silicic acid is slightly soluble in water, it can be used by dissolving it in an ammonium-based alkaline solution. Further, the sulfur-containing anion is also chemically active with respect to the redox reaction, but can be converted into colloidal form.

The amount of the colloidalization aid added is not particularly limited and may be adjusted according to the particle size of the desired colloidalized particles. For example, the particle size of the colloidalized particles may be 500 nm or less. In the case of using silica or aluminum silicate, preferably 2 ×
It is 10 ^{−4 to} 2 × 10 ⁰ mol. When the addition amount is less than 2 × 10 ⁻⁴ mol, the obtained colloidalized particles are immediately restored to the network structure particles due to aggregation and coarsen, which is not preferable. On the other hand, if the amount exceeds 2 × 10 ⁰ mol, the corrosion resistance of the film formed by the coating composition used in the present invention containing the colloidalized particles thus obtained tends to decrease, which is not preferable. More preferably, it is in the range of 2 × 10 ⁻³ to 2 × 10 ⁻² mol.

Water, which is the main component of the colloidal particles, is preferably ion-exchanged water or pure water, which has a small amount of impurities. The total amount of water is 1000, which is a combination of dry silica or dry aluminum silicate and water.
It is 950 to 800 parts by weight with respect to parts by weight.

The particle size of the colloidalized particles thus obtained can be adjusted by adjusting the addition amount of the colloidalization aid.
It can be granulated to a desired particle size. For example, when it is added to the coating composition for an organic coating of a highly anticorrosive precoated steel sheet, the thickness is preferably 500 nm or less, more preferably 150 to 250 nm.

The addition of the colloidalized particles to the coating composition used in the present invention is carried out during the manufacturing process of the paint (pre-addition) or to the completed paint (post-addition). The colloidalized particles are added to the coating composition used in the present invention by using a dispersion mixing device such as a paint shaker, a disper, a ball mill, a sand grind mill, a kneader and a dissolver.

When used for forming the rust preventive coating film for coating base, the coating composition I, the coating composition II or the coating composition III contains at least one of the above rust preventive pigment and fine particle silica. In addition, rust preventive agents such as anionic adsorptive inhibitors;
A chelating agent such as phytic acid and gallic acid may be contained. The coating composition I, the coating composition II, or the coating composition III is added to at least one of the above-mentioned rust preventive pigment and fine particle silica, and a rust preventive agent such as an anionic adsorptive inhibitor; phytic acid and gallic acid. The one containing a chelating agent or the like is referred to as "coating composition IV". The anionic adsorptive inhibitor is not particularly limited, and examples thereof include Irgacore (manufactured by Ciba Geigy). The amount of the anionic adsorptive inhibitor added is 0 to 5 parts by weight of the active ingredient of the anionic adsorptive inhibitor with respect to 100 parts by weight of the solid content of the coating composition I, the coating composition II or the coating composition III. However, it is preferable to increase or decrease the added amount depending on the degree of water solubility. That is, in the case of a substance which is ionized in water or which is hardly insolubilized after baking, it is preferable to reduce the addition amount.

In the present invention, the above coating composition I, coating composition II or coating composition I
When II is used for forming a lubricious anticorrosive film, the coating composition I, the coating composition II or the coating composition III, or the coating composition IV derived therefrom, based on 100 parts by weight of a solid content, is used. Further, it is preferable to add 3 to 15 parts by weight of wax in terms of solid content. Hereinafter, this is referred to as "coating composition V". The wax is not particularly limited as long as it can be dispersed in water, and examples thereof include paraffin wax, microcrystalline wax, and polyethylene wax (examples of polyethylene wax having an average molecular weight of 2000 to 8000, Disparlon SE21 manufactured by Kusumoto Kasei Co., Ltd.).
0-15T, Dispallon SE480-10T manufactured by the same company,
Examples include Chemipearl WF640 manufactured by Mitsui Oil Co., Ltd., Chemipearl W700 manufactured by Mitsui Oil Co., Ltd., polypropylene wax, polybutene wax, and the like. In addition to the above wax, a fluororesin such as polytetrafluoroethylene,
Fluorine-based solid lubricants such as carbon fluoride, graphite, metal soaps, etc. that can be mixed in the water-based composition can be used.

In the present invention, the above coating composition I, coating composition II or coating composition I
When II is used to form an anticorrosive film for automobiles,
With respect to 100 parts by weight of the solid content of the coating composition V, a melamine cyanurate compound of 0.05 to 25 is further added.
It is preferred to add parts by weight. Hereinafter, this is referred to as "coating composition VI". When the amount of melamine cyanurate added is less than 0.05 parts by weight, the effect of preventing the adhesion failure at the base metal interface due to an electrical load during electrodeposition coating disappears, as described later, and 25 parts by weight is added. When it exceeds the above range, the uniformity and denseness of the film are lost, and in the case of thin film coating, the barrier effect is hindered, which is not preferable.

The above melamine cyanurate is a compound having an isocyanuric ring-containing planar structure and has the formula (C ₆ H ₉
Is represented by N ₉ O ₃₎ n, for example, 2,4,6-triamino-1,3,5-triazine (hereinafter "melamine"),
An equimolar addition compound with 2,4,6-trihydroxy-1,3,5-triazine (hereinafter “cyanuric acid”) and its tautomer, and in the solid state, a melamine molecule and a cyanuric acid molecule. Are alternately adjacent to each other in a weak hydrogen bond state, and it is presumed that crystals having the following plane structure are formed.

[0068]

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In the formula, ● is carbon, ◯ is nitrogen, ◎ is oxygen,
Represents hydrogen, M represents a melamine molecule, and C represents a cyanuric acid molecule. Further, the three-dimensional structure is presumed to be a so-called graphite type, which is a stacked structure having a constant surface spacing as described below.

[0070]

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In the formula, M and C are the same as above. Examples of these melamine cyanurate compounds include Japanese Examined Patent Publication No. 60-338.
The manufacturing method is described in Japanese Patent No. 50, and MC series (MC-FW, MC-PW, MC-BW, manufactured by Nissan Chemical Industries, Ltd.
MC-UW, MC-420, MC-520, MC-60
Examples thereof include those commercially available. In addition, it is possible to include melamine cyanurate in the clear layer so as to exhibit the same pearly luster as that of mica coating in metallic coating of automobiles and the like.
However, it is irrelevant to the present invention.

The above melamine cyanurate compound has good acid resistance and alkali resistance, and is stable in the range of pH 1 to 14 without chemical change. On the other hand, during cationic electrodeposition coating, the bottom of the electrodeposition coating film is exposed to about pH 12. Therefore, by using the melamine cyanurate compound, the rust preventive coating for automobiles formed by the present invention,
It has the effect of preventing the adhesion failure at the interface of the base metal due to the electrical load during electrodeposition.

The melamine cyanurate compound is poorly soluble in water and has heat resistance. Furthermore, it does not dissolve in an organic solvent used for general paints, but only slightly dissolves in dimethyl sulfoxide at 0.011 g / 100 ml at 70 ° C. Therefore, it does not dissolve in water that penetrates under the coating film during electrodeposition coating, and does not become a factor that inhibits electrodeposition.

The coating composition used in the present invention may further contain a pigment, a solvent, an additive and the like as other components within the range not inconsistent with the constitution of the present invention.

The pigment is not particularly limited, and examples thereof include titanium oxide, phthalocyanine blue, phthalocyanine green, quinacridone, indanthrone, perylene, anthrapyrimidine, carbon black, benzimidazolane, graphite, yellow iron oxide, red iron oxide. And the like; pigments such as calcium carbonate, gypsum, clay, and talc. The content of the pigment is 0. 0, based on 100 parts by weight of the resin solid content of the coating composition.
It is preferably set in the range of 5 to 30 parts by weight.

Examples of the solvent include water; alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol, butyl alcohol, isobutyl alcohol, 2-butyl alcohol, benzyl alcohol and cyclohexanol; acetone, methyl ethyl ketone, methyl isobutyl ketone, Examples thereof include ketone type hydrophilic organic solvents such as cyclohexanone, isophorone, and diacetone alcohol, and mixtures thereof.

Examples of the above-mentioned additives include antifoaming agents, leveling agents, anti-repellent agents, gloss improvers, anti-settling agents, wetting agents (surfactants), lubricants, preservatives and dustproofing agents. You can

The coating composition used in the present invention is prepared by using an apparatus such as a paint shaker, a disper, a ball mill, a sand grind mill, a kneader, a dissolver or the like which is commonly used in the production of a paint, and water is used as a solvent. It can be used by adjusting the viscosity.
At this time, a hydrophilic organic solvent can be used in combination with water as long as the emulsion is not destroyed.

In the present invention, the metal to be coated may be pretreated before the electrolytic treatment in order to prevent the material from rusting and improve the adhesion of the coating. . Examples of such pretreatment include degreasing treatment such as acid and alkali washing.

In the present invention, the coating composition I, the coating composition II, the coating composition III or the coating composition IV is a non-volatile residue as the treatment method for the rust prevention of the steel sheet and the coating base treatment. Can be carried out by diluting with water so as to be 10 to 20% and subjecting the degreased steel plate surface to an anodic electrolytic treatment. The coating composition has a pH of 6.0 to
9.0 is preferable. The dry film thickness of the film formed by the anode electrolysis treatment is preferably 0.1 to 10 μm. If it is less than 0.1 μm, the uniformity of the film is impaired, pinholes are likely to occur and corrosion is likely to occur, and if it exceeds 10 μm, strain is likely to occur and it does not contribute to wet adhesion.
More preferably, it is 0.2 to 6 μm. More preferably, it is 0.2 to 3 μm.

Further, in the case of carrying out the coating base treatment of the galvanized surface, the coating composition I, the coating composition II or the coating composition III containing silica can be used. With galvanized painting,
Normally, a primer containing an anticorrosive pigment is applied on the surface of the coating, so an anticorrosive pigment is not necessary for this surface treatment of the coating. May be used.

As the above-mentioned silica, dry silica, wet silica and the like are used, but dry silica having few miscellaneous ions such as alkali metals is preferable. The amount of silica added is preferably 1 to 20 with respect to 100 parts by weight of the solid content of the composition.
Parts by weight. In the case where the zinc plating surface is subjected to coating undercoating treatment, it is preferable to perform anode electrolytic treatment so that the dry film thickness of the coating film is 0.1 to 5 μm. Film thickness is 0.1
If it is less than μm, pinholes are generated and the corrosion resistance and wet adhesion are deteriorated. If it exceeds 5 μm, the film peels off during bending and the film adhesion is impaired, which is not preferable. More preferably, it is 0.5 to 3 μm.

If necessary, the coating of the metal material (for example, a galvanized steel sheet) on which the coating is formed according to the present invention can be further coated. In this case, the electrolytically treated metal may be coated as it is without being washed with water, or the electrolytically treated metal may be washed and then coated. If necessary, the coating may be baked before applying the coating. The coating may be performed by undercoating (primer coating) and then topcoating, or simply topcoating (topcoat). In order to improve the corrosion resistance, it is desirable to apply an undercoat (primer coat) on the formed film. The primer coat has a function of protecting the material from a corrosive action and imparting adhesion to the surface of the metal plate, the surface treatment film and the top coat film. The thickness of the primer coat film is usually 1 to 7 μm when dried. The baking is carried out within a short time under the conditions of the optimum temperature and time for the coating resin used.

The preferable film thickness in the top coat is 7 to 50 μm (when dried). If this film thickness is less than 7 μm, the undercoating material cannot be hidden due to poor coloring power, and if it exceeds 50 μm, there is a risk of pinhole formation during baking at high temperature in a short time. , Not preferable. Optimum conditions for baking temperature and time are set according to the topcoat paint used.

The coating system to be combined with the film formed by the present invention is not limited to the above, and further,
The type of resin may be any of organic solvent type, water type and powder type. Further, the coating method of the above-mentioned undercoat coating and top coating is not particularly limited, and a usual coating method such as air spray coating, airless coating, electrostatic coating or the like can be used.

If necessary, the coating of a metal material (for example, a galvanized steel sheet) on which the coating has been formed according to the present invention may be further subjected to electrodeposition coating under ordinary anode electrodeposition conditions.

In the present invention, as a treatment method for carrying out the anti-lubrication treatment, the coating composition V is diluted with water to a concentration suitable for coating, and the dried film thickness of the coating is applied to a galvanized steel sheet or the like. Of 0.1 to 5 μm can be used for anodic electrolytic treatment. When the film thickness is less than 0.1 μm, pinholes are generated, corrosion resistance and wet adhesion are deteriorated, and 5 μm
If it exceeds m, the film peels off during processing and brushing occurs, which is not preferable. More preferably 0.5 to 3 μm
Is.

In the present invention, as a treatment method for carrying out anticorrosion treatment for automobiles, coating composition VI can be used to subject a galvanized steel sheet for automobiles to an electrolytic electrolytic treatment. Usually, after that, it is dried, and then a cation or anion electrodeposition coating is further applied thereon so that the dry film thickness is 15 to 40 μm, and if necessary, an alkyd resin, polyester resin or acrylic resin-based intermediate coating composition. Can be applied to give a dry film thickness of 20 to 60 μm, and then an automotive topcoat paint such as acrylic resin, polyester resin or fluororesin can be used.

[0089]

In the present invention, a coating composition containing a resin having at least one of a phosphoric acid group and a phosphonic acid group is used to perform an anodic electrolytic treatment at a low electrolytic voltage of 1 to 20V. , The phosphoric acid group or phosphonic acid group in the resin reacts with metals such as iron and zinc eluted in the anode reaction to form an insoluble salt of the phosphoric acid group or phosphonic acid group bound to the resin and these metals. To do. The resin-metal salt composite film thus formed is a resin film simply coated with a resin having a phosphoric acid group or a phosphonic acid group, or a phosphate formed simply by anodic electrolytic treatment of a metal in an aqueous phosphoric acid solution. Compared with a film, the metal surface is more protected, and even a thin film can be an anticorrosion film with excellent corrosion resistance.

Further, by using a resin having a phenol or bisphenol segment as the resin having at least one of a phosphoric acid group and a phosphonic acid group, the adhesiveness due to the wet adhesion of the secondary hydroxyl group contained is excellent. A coating base can be formed. By using together with other anion type resin such as aqueous phenol resin,
These anionic resins migrate and are adsorbed on the anode surface during the anode electrolysis treatment to facilitate the formation of the resin composite film, and also improve the base adhesion and the topcoat adhesion. Furthermore, by using a resin having a functional group that reacts with a hydroxyl group or a carboxyl group, it is possible to mask the hydrophilic groups in the resin film and improve the water resistance.

The anodic electrolytic treatment conditions of the present invention make it possible to form a metal phosphate film with a small reaction amount of metal, so that the generation of sludge can be prevented. Further, it is possible to easily form a good film on an object to be coated having a shape that cannot be subjected to a usual coating method such as a roll coating method. Furthermore, since the processing time is short, the processing steps can be shortened.

[0092]

EXAMPLES The present invention will be described in more detail below with reference to resin production examples and examples, but the present invention is not limited thereto.

Resin Production Example 1 94 parts by weight of carboxylic acid, 405 parts by weight of 37% formalin and 211 parts by weight of an aqueous sodium hydroxide solution were mixed and mixed at 50 ° C.
And reacted for 2 hours. After neutralizing with hydrochloric acid, ethyl acetate / n-
Extract with a mixed solvent of butanol = 1/1 to obtain a solid content of 80
% Resol type phenolic resin solution was obtained.

Resin Production Example 2 A raw material having the following composition was charged into a container equipped with a stirrer, a temperature controller and a decanter, and heated while stirring. Soybean fatty acid 34 parts by weight Trimethylolpropane 34 parts by weight Trimellitic anhydride 9 parts by weight Isophthalic acid 25 parts by weight Xylene 1 part by weight Dibutyltin oxide 0.5 parts by weight Water produced by reaction is azeotropically distilled with xylene. It was removed, and heating was continued until the acid value became 39 and the hydroxyl value became 140 to terminate the reaction. The obtained resin is added to the nonvolatile content 70
It was diluted with butyl cellosolve so as to be a weight% to obtain an alkyd resin varnish. The resin varnish is theoretically 100% neutralized with triethylamine, and the non-volatile content is 4% with deionized water.
The water-soluble alkyd resin varnish was obtained by adjusting the content to be 0% by weight. The substance had a substantial acid value of 33.

Example 1 Blending ingredients were mixed in the following blending ratio to obtain a coating composition. Formulation XU-8096.07 100% by weight (solid content conversion) Cymel 328 40% by weight (solid content conversion) In the above composition, XU-8096.07 is a phosphoric acid modified product of a bisphenol epoxy resin manufactured by Dow Chemical Japan ( Acid value 12, dimethylethanolamine (DMEA)
Neutralization 100%) and Cymel 328 represent iminomethylol melamine manufactured by Mitsui Cytec. The composition obtained is diluted with water to obtain an aqueous dispersion having a nonvolatile content of 20%, and the pH is adjusted.
The bath liquid was adjusted to 8.0 to 9.0. A cold-rolled steel sheet (JIS G) degreased using this with a bath temperature of 20 to 25 ° C
3141 SPCCD-SD) was used to carry out the anode electrolytic treatment of the experimental example shown below to obtain a treated steel sheet.

(1) Evaluation of Film Formability In Experimental Examples 1 to 13, the anode electrolysis voltage was set to the value shown in Table 1, and the boosting time until the anode electrolysis voltage was reached is shown in Table 1.
As shown in Table 1, various times were set within 3 minutes to obtain films having various film thicknesses shown in Table 1. However, in Experimental Examples 2, 3 and 7, after reaching the anode electrolysis voltage shown in Table 1, the voltage was further held for 90 seconds, 90 seconds and 60 seconds, respectively. Except for Experimental Examples 2 and 6, after the anode electrolysis, after washing with water, each treated steel sheet was baked at 140 ° C. for 10 minutes. In Experimental Examples 2 and 6, after the anode electrolytic treatment,
It was baked without washing with water. Evaluation The appearance of the baked steel plate was evaluated. The evaluation criteria are as follows. The results are shown in Table 1. ○: Abnormal and glossy film ○ △: Between ○ and △ △: There are a few marks of bubbles ×: Rupture occurs

(2) Evaluation of Corrosion Resistance In Experimental Examples 21 to 24, the voltage boosting rate was set to the value shown in Table 2 and the anode electrolysis treatment was performed until the anode electrolysis voltage reached 5 V. A treated steel sheet was obtained in the same manner as in (1), and after the anode electrolytic treatment, each treated steel sheet was baked at 140 ° C. for 10 minutes without being washed with water. The appearance was good. Evaluation Odeselect 500 (manufactured by Nippon Paint Co., Ltd.) having a film thickness of 25 to 30 μm is further applied as an overcoat on the treated steel sheet.
The one-sided peeling width after the salt spray test was measured for the paint coated on. The measurement was carried out by degreasing the obtained top-coated steel sheet, using a sharp knife (cutter knife) to make scratches that reach the substrate in a diagonal line, and after subjecting it to a salt spray test for 100 hours, wipe off and dry the surface water, The adhesive tape was pressed along the cut, and the width of the peeled coating film after rapid peeling was measured. Peeling width on one side from the cut part (m
The corrosion resistance was evaluated by m). The results are shown in Table 2.

At a voltage boosting rate of 0.17 V / sec, electricity was supplied until the anode electrolysis voltage of 5 V was reached, and this voltage was maintained for 90 seconds to obtain a film thickness of 9.5.
A μm film was obtained and evaluated in the same manner as above. The appearance was good and the corrosion resistance was 2 mm. Further, a treated steel sheet was obtained in the same manner as in Experimental Example 21, except that the steel sheet was washed with water after the anode electrolysis treatment, and evaluated in the same manner as above. Thickness 0.7m
m and corrosion resistance were 1.1 mm.

Example 2 Formulation XQR-711-1352.61 (phosphoric acid modified product of bisphenol type epoxy resin, manufactured by Dow Chemical Japan) for application to a general industrial coating undercoating film was treated with dimethylethanolamine (DMEA). After neutralization with 100% (neutralization rate 100%), water was added to emulsify (acid value 22, average weight molecular weight about 10,000) 100 parts by weight solid content, iminomethylol melamine (Cymel 327, manufactured by Mitsui Cytec) Solid content 40 parts by weight, Day Quest 2
041 (manufactured by Nippon Monsanto, ammonia neutralization) solid content 0.5 part by weight, Hydran HW960 (manufactured by Dainippon Ink and Chemicals, Inc.) solid content 10 parts by weight, colloidal silica (Adelite AT20N, manufactured by Asahi Denka Kogyo Co., Ltd.) solid content 10 parts by weight, anticorrosive pigment (molybdic acid type LF BOSEY PM30
0, made by Kikuchi dye company, 2 parts by weight, anticorrosive (Irgacoa 25
(2, manufactured by Ciba-Geigy Co., Ltd.) 2 parts by weight were sequentially added and mixed uniformly by a disper. Dilute this with water to a solid content of 20%, adjust with DMEA and phosphoric acid, and adjust the pH.
Was set to 6.5 to obtain a water-based anticorrosive coating composition for a coating base. The rust preventive pigment (LF Bosei M-PSN, manufactured by Kikuchi Dye Company) is an alkyd resin varnish (obtained in Resin Production Example 2, acid value 39, hydroxyl group 1) in order to stabilize the dispersion.
40) was used to disperse beads in an SG mill to form a pigment paste (resin: pigment = 7: 20). The Irga core 252 was neutralized with ammonia to prepare a water paste having an appropriate solid content, and used the required amount. A degreased steel sheet (JIS G 3141 SPCC-
SD), anode electrolysis voltage 5V, voltage boosting rate 0.1
Anodically electrolyzed at 67 V / sec, baked at 140 ° C. for 10 minutes to form a film with a thickness of 2 μm, and further Olga Select 120 White (Nippon Paint Co., Ltd., melamine alkyd solvent type paint) Was applied to give a dry film thickness of 25 to 30 μm to obtain a coated steel sheet.

Performance test (1) Topcoat water resistance A sample of the obtained coated steel sheet was immersed in tap water at 40 ° C for 1 hour.
After soaking for 20 hours, FIG. 2 (ASTM, D610-6
The coating film blister (blister) was evaluated on the basis of the rust area determination chart according to 8. No. 2 in FIG. 2, 4, 6 and 8
Represents the size of the blisters, and F, M, MD, and D represent the densities of the respective blisters.
The evaluation criteria are as follows. ◯: No blister Δ: Blister F (ASTM density standard) X: Blister M (ASTM density standard) XX: Blister MD or D (ASTM density standard) (2) Topcoat corrosion resistance One side peeling width after 240-hour salt spray test ( mm) was measured in the same manner as in Example 1. The evaluation results are shown in Table 3.

Example 3 Formulation XQR-711-1352.60 (a phosphoric acid modified product of a bisphenol type epoxy resin, manufactured by Dow Chemical Japan Co., Ltd., neutralized with DMEA , for the application of an electrodeposition coating to an undercoat film) Sum ratio 90%) Emulsified product, acid value 12, average weight molecular weight about 10,000) Solid content 100 parts by weight, methoxy-isobutoxy modified melamine (Cymel 238, manufactured by Mitsui Cytec Co., Ltd.) solid content 30 parts by weight, ammonium dihydrogen phosphate Solid content 2 parts by weight, Hydran HW
935 (manufactured by Dainippon Ink and Chemicals, Inc.) solid content 20 parts by weight, Aerosil MOX170 (manufactured by Nippon Aerosil Co., Ltd.) colloidal with boric acid, solid content 15 parts by weight, melamine cyanurate MC-420 (manufactured by Nissan Chemical Industries, Ltd.) )
5 parts by weight of solid content was blended in the same manner as in Example 3 to obtain a solid content of 2
The mixture was diluted with water to 0% to adjust the pH to 6.5 to obtain a coating composition for electrodeposition coating base. The Cymel 238 was used after being premixed with XQR-711-1352.60 and then neutralized and emulsified.

Using the above composition, a steel plate (without chromate treatment) was subjected to an anode electrolysis voltage of 5 V and a voltage boosting rate of 0.1.
Anode electrolyzed at 67 V / sec and washed with water for 14
The film was baked at 0 ° C. for 10 minutes to form a film having a film thickness of 0.7 μm. On top of that, a cationic electrodeposition paint Power Top U2550 (manufactured by Nippon Paint Co., Ltd.) having a dry film thickness of 20-
Electrodeposition coating was performed so as to have a thickness of 25 μm to obtain a coated steel sheet. Performance Test The topcoat water resistance after 240 hours of immersion and the topcoat corrosion resistance after 400 hours of salt spray test were tested as in Example 2. The evaluation results are shown in Table 3.

Example 4 Formulation for Application to Lubricant Anticorrosion Coating Composition XQR-711-1352.60 (manufactured by Dow Chemical Japan, phosphoric acid modified product of bisphenol type epoxy resin, DMEA neutralized (neutralized 100%) emulsified,
Acid value 12, average weight molecular weight about 10,000) Solid content 100
Parts by weight, iminomethylol melamine (Cymel 32
8, Mitsui Cytec Co., Ltd.) solid content 30 parts by weight, Epocros K-1050E (Nippon Shokubai Chemical Co., Ltd.) solid content 10
Parts by weight, ammonium monohydrogen phosphate 2 parts by weight, Hydran HW940 (manufactured by Dainippon Ink and Chemicals, Inc.) solid content 20
Parts by weight, aqueous phenol resin (obtained in Resin Production Example 1) solid content 20 parts by weight, colloidal silica (Adelite AT20N, manufactured by Asahi Denka Co., Ltd.) solids content 15 parts by weight, Chemipearl W700 (Mitsui Petrochemical Industry Co., Ltd.) 5 parts by weight of a solid content and 5 parts by weight of a solid content of an anticorrosive agent (IRGACORE 252, manufactured by Ciba Geigy) were blended in the same manner as in Example 2 to obtain a solid content of 20.
% To adjust the pH to 8.0 to obtain a lubricating anticorrosive coating composition. Using the above composition, an electrogalvanized steel sheet (without chromate treatment) was subjected to an anode electrolysis treatment at an anode electrolysis voltage of 5 V and a voltage boosting rate of 0.33 V / sec, and baked at 140 ° C. for 10 minutes to obtain a base-treated steel sheet. It was Odeselect 100 White (a melamine alkyd water-based paint manufactured by Nippon Paint Co., Ltd.) was further applied thereon so that the dry film thickness was 25 to 30 μm to obtain a coated steel plate.

Performance Test (1) Thin Film Corrosion Resistance A salt spray test was conducted on the ground-treated steel sheet obtained by anodic electrolytic treatment without applying a top coat until 0.3% rust generation in FIG. 1 occurred. The time was evaluated. The evaluation criteria are as follows. The results are shown in Table 3. ◯: White rust did not occur for 500 hours or more Δ: White rust occurred within 100 hours X: White rust occurred within 10 hours XX: White rust occurred within 1 hour

(2) MEK rubbing test After drying the obtained base-treated steel sheet, a gauze dipped in methyl ethyl ketone (MEK) was rubbed against the coating surface while being pressure-bonded with a load of 300 g, and the number of times until the coating was broken was determined. It was measured and evaluated. The evaluation criteria are as follows.
The results are shown in Table 3. ◎: 200 times or more ○: 100 or more and less than 200 times △: 10 times or more and less than 100 times ×: Less than 10 times

(3) Alkali resistance The obtained surface-treated steel sheet was immersed in Surf Cleaner 53S (manufactured by Nippon Paint Co., Ltd.), which is an alkaline degreasing agent, at 45 ° C. for 10 days.
After soaking for a minute, the state of the film surface was observed and evaluated according to the following evaluation criteria. The results are shown in Table 3. ⊚: No abnormality ○: Very little whitening △: 50% whitening ×: Full whitening with elution

(4) Workability: Cylindrical drawing test The obtained base-treated steel sheet was processed with the coating surface on the die side, and the coating-peeling powder adhering to the die was sampled with cellophane tape and evaluated from that degree. For the powdering, the narrowed portion was peeled off with a tape, and the degree of peeled powder was evaluated. The press conditions at this time were as follows. Wrinkle suppression pressure: 3 tons Punch diameter: 50 mmφ Blank diameter: 95 mmφ Drawing ratio: 1.92 Drawing speed: 300 mm / sec

The appearance was observed and evaluated according to the following evaluation criteria. The results are shown in Table 3. ⊚: No adhesion to the die ◯: Some adhesion to the die Δ: Adhesion to the die was between ○ and × ×: A large amount of adhesion to the die The powdering was evaluated according to the following evaluation criteria. The results are shown in Table 3. ◎: No peeling powder ○: Some peeling powder △: Intermediate between ○ and × ×: A large amount of peeling powder

(5) Applicability of overcoating After the electrolytic treatment of the anode was carried out in the same manner as above, the baking was carried out at the reaching plate temperature of 180 ° C. for 20 seconds to carry out the base treatment,
On top of that, Olga Select 120 (made by Nippon Paint Co., Ltd.)
Was spray-coated and baked at 130 ° C. for 15 minutes to apply a top coat. The test is 2 mm after painting 1 day
Put 100 pieces of width squares into the coating film, extrude from the back side of the 3mm coated plate with an Erichsen tester, peel off with a commercially available adhesive tape, and measure the adhesion with (the number of squares of the peeled tape) / 100 displayed. The dry film thickness of the top coat is 3
It was 0 ± 3 μm. The results are shown in Table 3.

(6) Topcoat water resistance The coated steel sheets obtained in the examples were treated at 240 ° C for 240 hours.
The test and evaluation were performed in the same manner as in Example 2 except that the test piece was immersed in tap water. The results are shown in Table 3.

(7) Topcoat Corrosion Resistance Regarding the coated steel sheets obtained in the examples, JIS 2371
According to the above, a salt spray test was performed for 480 hours to observe rust on the coated surface, and the flat surface corrosion resistance was evaluated according to the following evaluation criteria. The results are shown in Table 3. ◎: No abnormality ○: Some white rust △: White rust on 1/2 of coated surface ×: White rust on entire surface

Comparative Example 1 The composition obtained in Example 1 was diluted with water to give a nonvolatile content of 20.
% Aqueous dispersion, and the pH was adjusted to 8.0 to 9.0 to obtain a bath liquid. Using this, a cold-rolled steel sheet (JIS G 3141 SPCCD-S) degreased at a bath temperature of 20 to 25 ° C.
Using D), the anode electrolytic treatment of the experimental example shown below was performed to obtain a treated steel sheet. (1) Evaluation of film-forming property In Experimental Examples 14 to 19, treated steel sheets were processed in the same manner as in Example 1 except that the anode electrolysis voltage and the boosting time until reaching the anode electrolysis voltage were the values shown in Table 1. After the obtained treated steel sheets were washed with water, each treated steel sheet was baked at 140 ° C. for 10 minutes to evaluate the appearance. However, in Experimental Example 17,
After reaching the anode electrolysis voltage shown in Table 1, the voltage was held for another 4 seconds. In Experimental Example 20, the appearance was evaluated in the same manner as in Example 1 except that a steel sheet that was simply immersed in a bath solution for 10 minutes and drained without using electricity was baked at 140 ° C. for 10 minutes. The results are shown in Table 1.

(2) Evaluation of Corrosion Resistance In Experimental Examples 25 to 26, the voltage boosting rate was set to the value shown in Table 2 and the anode electrolysis was performed until the anode electrolysis voltage shown in Table 2 was reached. A treated steel sheet was obtained in the same manner as in No. 1, and after the anode electrolytic treatment, each treated steel sheet was baked at 140 ° C. for 10 minutes without washing with water. The appearance of Experimental Example 25 was good, but in Experimental Example 26, rupture occurred. Regarding the top-coated steel sheet obtained in the same manner as in Example 1, in the same manner as in Example 1, the peeling width (mm) on one side from the cut portion was measured to evaluate the corrosion resistance. Table 2 shows the results
It was shown to. In addition, what was directly overcoated on the degreased steel sheet without the anode electrolytic treatment was evaluated in the same manner as above. The corrosion resistance was 10 mm. Further, a top-coated steel sheet was obtained and evaluated in the same manner as in Experimental Example 25 except that the anode electrolysis voltage was 0.8 V and the voltage boosting rate was 0.05 V / sec. The corrosion resistance was 5 mm. Furthermore, p
Phosphoric acid aqueous solution adjusted to H8.8 (phosphate ion concentration 2
In the case of electrolysis under the anodic electrolytic treatment conditions of the present invention in 1.4 mM), the coating thickness was 0.1 μm or less, the peeling width on one side was 6 mm, and the corrosion resistance was insufficient.

[0114]

[Table 1]

From the results shown in Table 1, the anode electrolysis voltage was
It has been found that when the treatment time is set to 20 V and the treatment time is set within the range of 10 seconds to 3 minutes, a film having a film thickness of 10 μm or less and a good appearance is formed.

[0116]

[Table 2]

From the results of Table 2, the voltage boosting rate is 0.04
It has been found that a thin film having excellent corrosion resistance is formed by setting the range to 0.45 V / sec, particularly 0.08 to 0.40 V / sec.

[0118]

[Table 3]

From the examples, according to the present invention, even a thin film having a film thickness of 10 μm or less has good appearance and corrosion resistance.
It was found that the effect of improving the corrosion resistance was remarkable when the thickness was m or less. Further, even if the resin adhering to the surface was removed by washing with water after the treatment, almost no deterioration in corrosion resistance was observed. When the same composition was applied by bar coating and compared, the film obtained according to the present invention showed a corrosion resistance equal to or higher than that of a coating film of the same thickness obtained by applying the same composition by bar coating. Well, in particular, when the film thickness is 3 μm or less, when the same composition is applied by bar coating, the peeling width becomes about 10 mm or more, which is extremely high in corrosion resistance compared to the fact that there is substantially no corrosion resistance. It was

[0120]

EFFECTS OF THE INVENTION Since the present invention has the above-mentioned constitution, it is possible to form a uniform film even on a non-planar metal product by using the aqueous coating composition, and to form a good coating base. It is possible to provide a method for preventing rust and forming a coating base film. When the present invention is used as a coating base treatment instead of a phosphate treatment, it is possible to realize sludge-less, space-saving treatment, and to eliminate waste liquid treatment. In addition, by using a lubricating rust-preventive coating composition containing wax, melamine cyanurate, etc., a rust-preventive coating composition for automobiles, there is no need for chromate treatment of the coating base, excellent corrosion resistance, water resistance, etc. It is possible to obtain a coated steel sheet that can maintain its properties. Further, the present invention can provide a film forming method suitable for a coating base even if the film thickness is 3 μm or less by forming a resin composite film of a phosphate film and an electrodeposition resin film. .

[Brief description of drawings]

FIG. 1 is a diagram of evaluation of surface rust occurrence state according to ASTM, D610-68.

FIG. 2 is a diagram of blister evaluation.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Toshihiro Okai 19-17 Ikedanaka-cho, Neyagawa-shi, Osaka Japan Paint Co., Ltd.

Claims (8)

[Claims] 1. A method for forming a film of an aqueous coating composition on the surface of a metal, wherein the aqueous coating composition comprises at least one of a phosphoric acid group and a phosphonic acid group.
A coating composition containing a resin having seeds, which is obtained by immersing a metal in an aqueous solution or an aqueous dispersion of the aqueous coating composition, followed by an electrolytic voltage of 1 to 20 V and a voltage boosting rate of 0.04 to 0.45 V. / Sec, a treatment time of 10 seconds to 3 minutes, the method of forming a metal surface treatment film, characterized in that the metal is subjected to an anode electrolytic treatment. 2. The method for forming a metal surface treatment film according to claim 1, wherein the resin having at least one of a phosphoric acid group and a phosphonic acid group has a phenol or bisphenol segment. 3. A coating composition comprising a resin having at least one of a phosphoric acid group and a phosphonic acid group, wherein the resin solid content having at least one of a phosphoric acid group and a phosphonic acid group is 100 parts by weight. , And at least one selected from the group consisting of an aqueous phenolic resin, a polyurethane resin emulsion, a resin having a functional group capable of reacting with a hydroxyl group, and a resin having a functional group capable of reacting with a carboxyl group in terms of solid content of 10 to 10. The method for forming a metal surface-treated coating according to claim 1, which comprises 500 parts by weight. 4. A coating composition containing a resin having at least one of a phosphoric acid group and a phosphonic acid group is (a-1) a resin having at least one of a phosphoric acid group and a phosphonic acid group. 100 parts by weight of solid content, and
Aqueous phenolic resin, polyurethane resin emulsion,
At least one selected from the group consisting of a resin having a functional group that reacts with a hydroxyl group and a resin having a functional group that reacts with a carboxyl group is 10 to 500 in terms of solid content.
100 parts by weight of the solid content of the composition, and
(A-2) benzenesulfonic acid derivative, amine salt and ammonium salt thereof, naphthalenesulfonic acid derivative,
An amine salt and an ammonium salt thereof, an acidic phosphoric acid amine salt and an ammonium salt, and a phosphonic acid derivative,
0.1-5 parts by weight in terms of solid content of the acidic catalyst comprising at least one selected from the group consisting of the amine salt and the ammonium salt thereof, (a-1) and (a-).
A coating composition comprising 2).
A method for forming a metal surface-treated film as described above. 5. A coating composition containing a resin having at least one of a phosphoric acid group and a phosphonic acid group is (a) (a-1) at least one kind of a phosphoric acid group and a phosphonic acid group. 100 parts by weight of resin solid content having
Aqueous phenolic resin, polyurethane resin emulsion,
At least one selected from the group consisting of a resin having a functional group that reacts with a hydroxyl group and a resin having a functional group that reacts with a carboxyl group is 10 to 500 in terms of solid content.
100 parts by weight of the solid content of the composition, and
(A-2) benzenesulfonic acid derivative, amine salt and ammonium salt thereof, naphthalenesulfonic acid derivative,
An amine salt and an ammonium salt thereof, an acidic phosphoric acid amine salt and an ammonium salt, and a phosphonic acid derivative,
0.1-5 parts by weight in terms of solid content of the acidic catalyst comprising at least one selected from the group consisting of the amine salt and the ammonium salt thereof, (a-1) and (a-).
100 parts by weight of a solid content of the composition containing 2), and (b) 1 to 40 parts by weight of at least one of a rust preventive pigment having a conductivity of 600 μS / cm or less and fine particle silica, and an anionic adsorptive inhibitor. 2. A coating composition comprising 5 parts by weight or less of the active ingredient of 1.
A method for forming a metal surface-treated film as described above. 6. A coating composition containing a resin having at least one of a phosphoric acid group and a phosphonic acid group is (a) (a-1) at least one kind of a phosphoric acid group and a phosphonic acid group. 100 parts by weight of resin solid content having
Aqueous phenolic resin, polyurethane resin emulsion,
At least one selected from the group consisting of a resin having a functional group that reacts with a hydroxyl group and a resin having a functional group that reacts with a carboxyl group is 10 to 500 in terms of solid content.
100 parts by weight of the solid content of the composition, and
(A-2) benzenesulfonic acid derivative, amine salt and ammonium salt thereof, naphthalenesulfonic acid derivative,
An amine salt and an ammonium salt thereof, an acidic phosphoric acid amine salt and an ammonium salt, and a phosphonic acid derivative,
0.1-5 parts by weight in terms of solid content of the acidic catalyst comprising at least one selected from the group consisting of the amine salt and the ammonium salt thereof, (a-1) and (a-).
100 parts by weight of a solid content of the composition containing 2), and (b) 1 to 40 parts by weight of at least one of a rust preventive pigment having a conductivity of 600 μS / cm or less and fine particle silica, and an anionic adsorptive inhibitor. 5 parts by weight or less of the active ingredient of (a) and (b), and (c) a coating composition comprising at least one of a wax and a melamine cyanurate compound. A method for forming a metal surface treatment film according to claim 1. 7. The metal is steel, zinc, zinc-based alloy, zinc or zinc-based alloy plated steel, aluminum, aluminum-based alloy, or aluminum or aluminum-based alloy plated steel. 5. The method for forming a metal surface treatment film described in 5 and 6. 8. The method for forming a metal surface treatment film according to claim 1, 2, 3, 4, 5, or 6, the film thickness is 0.2 to 3
A metal characterized by being formed with a rust-preventive coating film having a thickness of μm.