JPH07179813A - Aqueous coating composition - Google Patents

Abstract

(57) [Summary] [Purpose] It is possible to obtain a coating film that has a high degree of curing and is firmly adhered to a metal plate by baking at low temperature for a short time, and is excellent in corrosion resistance, water resistance, weldability, and suitable for electrodeposition coating. Has conductivity,
Further, the present invention provides an aqueous coating composition for steel plate surface treatment, which can prevent the occurrence of powdering during processing. [Structure] Acid value is 25 to 100, and hydroxyl value is 35 to 20
0, 100 parts by weight of a resin varnish consisting of at least one of a water-soluble alkyd resin having a SP value of 10.0 to 11.0 and a water-soluble acrylic resin, an oxazoline compound, and a melamine resin having a curing start temperature of 140 ° C. or less. 10 to 200 parts by weight of at least one curing agent, a benzenesulfonic acid derivative, an amine salt and an ammonium salt thereof, a naphthalenesulfonic acid derivative, an amine salt and an ammonium salt thereof, and an acidic phosphoric acid amine salt and ammonium salt An aqueous coating composition comprising 0.5 to 5 parts by weight of a strongly acidic catalyst comprising at least one selected from the group consisting of salts.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aqueous coating composition for surface treatment, which imparts processing lubricity, corrosion resistance, etc. to a surface-treated steel sheet, and more specifically, an anticorrosive primer composition and a lubricating anticorrosive coating composition. And an anticorrosive coating composition for automobiles.

[0002]

2. Description of the Related Art Cold-rolled steel sheets and galvanized steel sheets are widely used for building materials, household appliances, automobiles and the like. These steel sheets are usually subjected to painting after forming and before assembling. At the stage of the forming process, a lubricating oil such as a press oil is applied to the surface of the steel sheet in order to improve its workability. However, with lubricating oil,
After pressing, a step of degreasing the lubricating oil is required before painting, which is economically disadvantageous, and the lubricating oil is scattered during the pressing and deteriorates the working environment.

Therefore, in recent years, for the purpose of resource saving, cost reduction, improvement of working environment, etc., a surface-treated steel sheet capable of forming a film having a lubricating function and a rust preventive function on the surface of a steel sheet without using a lubricating oil. Was proposed. Japanese Patent Laid-Open No. 5-394
Japanese Patent Laid-Open No. 58-58 discloses a technique of forming a resin film made of a specific polyethylene wax on the surface of a steel sheet to improve press formability and the like. Also, JP-A-1-3013
Japanese Unexamined Patent Publication No. 32 discloses a technique for obtaining moldability by double coating a specific amount of a chromate film and a resin film composed of a specific resin mixture.

From the viewpoint of labor saving, the above lubricating film is provided with anticorrosion property and adhesion to the top coating film, and after molding processing,
For applications that require direct coating of top-coat paint for finishing, or electro-deposition coating of automobile steel plates, etc., it has become possible to provide the coating with the necessary conductivity (special features). Kaihei 3-270932, etc.). Also, in the field of general anticorrosion paints, paints whose conductivity is adjusted in order to enhance water resistance and moisture resistance are also being developed (Japanese Patent Application No. 4-290339).

In the production of the above coating composition, the use of an organic solvent deteriorates the working environment during processing,
The problems of ignition, the necessity of installing an afterburner to prevent the solvent from being discharged to the outside, and other problems have led to the development of aqueous coating compositions. In the composition of such an aqueous coating composition, the hydrophilic groups of the resin are increased to make it aqueous, and an emulsifier or the like for emulsifying the resin is added, which results in accelerating water penetration. This is a cause of lowering the water resistance and the corrosion resistance, and there has been a need for a technical means that does not deteriorate the water resistance and the corrosion resistance even if the water resistance is changed.

Further, when the above aqueous coating composition is used as an anticorrosive primer composition, a primer layer having a normal film thickness is formed, and then an aqueous paint is wet-on-wet coated and baked by a two-coat-one-bake method. Unless the conditions of high temperature and long time are applied to the baking of the layer, the primer layer is liable to cause curing failure, and problems such as deterioration of moisture resistance, water resistance and corrosion resistance occur.

In recent years, in the surface-treated steel sheet production line on an industrial scale, energy saving and speeding up of treatment are being promoted. For example, at a relatively low temperature of about 150 ° C., 15
The current situation is that the requirements cannot be met unless the coating surface of the coating agent is cured in a short time of about a second to secure the film strength.

Further, recently, deep drawing and high speed processing have come to be performed. For this reason, the film on the processed part of the surface-treated steel sheet peels off due to the temperature rise of the mold, etc., and powder is generated (powdering), and the powder adheres to the processed part and the mold. There were problems such as deterioration of corrosion resistance of parts and deterioration of finished appearance.

[0009]

SUMMARY OF THE INVENTION In view of the above, the present invention is capable of obtaining a coating film having a high degree of curing and firmly adhering to a metal plate by baking at a low temperature for a short time, and having corrosion resistance, water resistance,
To provide an aqueous coating composition for surface treatment of steel sheet, which has excellent weldability, has conductivity suitable for electrodeposition coating, and can prevent generation of powdering during processing, and 2 coats 1 bake An object of the present invention is to provide an aqueous coating composition for a primer, which is sufficiently cured under the same baking conditions as one coat even when baked by the method, and is excellent in water resistance and corrosion resistance.

[0010]

SUMMARY OF THE INVENTION The gist of the present invention is to provide an aqueous coating composition having a water-soluble alkyd resin having an acid value of 25 to 100, a hydroxyl value of 35 to 200 and an SP value of 10.0 to 11.0. And 100 parts by weight of a resin varnish consisting of at least one of water-soluble acrylic resins, 10 to 200 parts by weight of a curing agent consisting of at least one of an oxazoline compound and a melamine resin having a curing start temperature of 140 ° C. or less, and a benzenesulfonic acid derivative. A strong acid catalyst comprising at least one selected from the group consisting of an amine salt and an ammonium salt thereof, a naphthalenesulfonic acid derivative, an amine salt and an ammonium salt thereof, and an acidic phosphoric acid amine salt and an ammonium salt. ~ 5 parts by weight,
It consists of the above. Another subject matter of the present invention is to constitute an anticorrosive primer composition, a lubricating anticorrosive coating composition and an anticorrosive coating composition for automobiles based on the above aqueous coating composition. The present invention is described in detail below.

The alkyd resin and acrylic resin used in the present invention are not particularly limited as long as they are water-soluble.
Fatty acid modified phthalic acid alkyd, maleic acid alkyd;
(Meth) acrylic acid ester etc. can be mentioned.

A water-soluble alkyd resin used in the present invention,
Either one or both of the water-soluble acrylic resins can be used. The water-soluble alkyd resin and water-soluble acrylic resin have an acid value (AV) of 25 to 100,
The hydroxyl value (OHV) is 35 to 200, and the SP value (solubility parameter) is 10.0 to 11.0. Acid value is 25
If the hydroxyl value is less than 35, or the hydroxyl value is less than 35 or the SP value is less than 10, the water-solubilization degree (hydrophilicity) is low, and the paint adhered to coating equipment other than the object to be coated during the coating process is absorbed in water. At the time of recovery, when the diluted paint recovered by the ultrafiltration method or the like is concentrated, resin separation or the like occurs, which causes a problem. vice versa,
When the acid value exceeds 100, the hydroxyl value exceeds 200, and the SP value exceeds 11, the water solubility (hydrophilicity) becomes too high, which causes a problem in water resistance of the coating film.

The above SP value (solubility parameter) is
It represents a measure of solubility and is calculated by:
References SUH, CLARKE [J. Polymer
Science, A-1, Vol. 5, pp. 1671-168.
Page 1 (1967)] Measurement temperature 20 ° C Sample 0.5 g of resin is weighed in a 100 ml beaker, 10 ml of good solvent is added using a whole pipette, and dissolved by a magnetic stirrer. Solvent Good solvent: dioxane, acetone Poor solvent: n-hexane, ion-exchanged water Turbidity point measurement Poor solvent is dropped using a 50 ml buret, and the point at which turbidity occurs is the dropping amount. Calculation The SP value δ of the resin was calculated by the following formula.

Δ = (V _ml ^1/2 δ _ml + V _mh ^1/2 δ _mh ) /
^{_{(V ml 1/2 + V mh 1/2}} ) V m = V 1 V 2 / (φ 1 V 2 + φ 2 V 1) δ m = φ 1 δ 1 + φ 2 δ 2 V i: solvent molecular volume (ml / Mol) φ _i : volume fraction of each solvent at the turbidity point δ _i : SP value of solvent ml: low SP value poor solvent mixed system mh: high SP value poor solvent mixed system

The hydroxyl value of the above water-soluble alkyd resin or water-soluble acrylic resin limited to the range of 35 to 200 is more preferably 100 to 200. If the hydroxyl value is less than 100, it will be difficult to easily wash the paint that has adhered to the coating equipment with water during the coating process, and the adhesion of the dry coating film to the substrate will decrease, so peeling and wet adhesion during lubrication Corrosion resistance also decreases due to the deterioration of the corrosion resistance.

More preferably, the above water-soluble alkyd resin or water-soluble acrylic resin is theoretically 100% neutralized and after the nonvolatile content is diluted to 3%, the nonvolatile content is up to 20% by ultrafiltration (UF). It is preferable that the resin component of the filtrate becomes 4% or less of the original resin when concentrated. The resin component of the filtrate includes a low molecular weight unreacted acid component remaining in the resin during the synthesis process and a low molecular acid component produced by hydrolysis of the varnish and the aqueous coating composition during storage.

If the amount of the low molecular weight unreacted acid component remaining in the resin during the synthesis process and the amount of the low molecular acid component produced by hydrolysis during storage of the varnish and the aqueous coating composition is less than 4%, Water resistance is improved. For such purpose, a resin containing as little water-soluble low molecular weight component as possible is selected and used, or when the resin is synthesized, for example, the reaction time is sufficiently long to synthesize a low molecular weight component in a small amount. You can use things.

Even with a normal water-soluble resin which has not been prepared with a particularly small amount of low-molecular components, the low-molecular components can be removed by concentrating a diluting solution dissolved or dispersed in water by an ultrafiltration method or a reverse osmosis method. It can be removed together with the solvent and used. From the viewpoint of concentration efficiency, the ultrafiltration method is preferable.

When the above water-soluble alkyd resin and water-soluble acrylic resin are theoretically 100% neutralized and the nonvolatile content is diluted to 3%, the nonvolatile content is concentrated and recovered to 20% by ultrafiltration. The acid value of the resin varnish thus obtained indicates the acid value of the carboxyl group substantially bound to the resin polymer, and thus this value is defined as “substantial acid value” in the present specification.

When the aqueous coating composition of the present invention is spray-coated, the paint that does not adhere to the object to be coated is collected in the wash water in the coating booth, and the paint components are concentrated and recovered from the recovered water by the ultrafiltration method. In some cases, the actual acid value is 31 to 100.
Are preferred.

In the present invention, at least one of an oxazoline compound and a melamine resin is used as a curing agent. The oxazoline compound used in the present invention has a structure represented by the following general formula [I]. The oxazoline compound easily reacts with a compound having a carboxyl group to cause the following ring-opening addition reaction.

[0022]

[Chemical 1]

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 the toughness of the coating film and increasing the glass transition temperature. The oxazoline compound is not particularly limited, but for example, Epocros K-1010E and Epocros K-102 manufactured by Nippon Shokubai Co., Ltd.
0E, Epocros K-1030E, Epocros K-10
50E, etc., of which Epocros K
-1030E and Epocros K-1050E are preferable because they give a coating film having a high glass transition temperature, toughness, and high adhesion. Also, Epocros K-1010E, Epocros K
Even with -1020E, 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 used in the present invention preferably has a glass transition temperature of 0 ° C. or higher. 0 ° C
When it is less than, low temperature and short time (about 150 seconds at 150 ° C)
Under the above baking conditions, a coating film excellent in adhesion to a steel plate and curing degree cannot be obtained.

The melamine resin used as the curing agent of the present invention has a curing initiation temperature of 140 ° C. or lower. 1
If the temperature is higher than 40 ° C, low temperature and short baking time
The degree of curing of the coating film is insufficient. Examples of the melamine resin satisfying the above conditions include Cymel 303 (manufactured by Mitsui Cyanamide Co., Ltd.) and Sumimar 50W (manufactured by Sumitomo Chemical Co., Ltd.) and other methoxy-modified melamine resins; Cymel 236, Cymel 23.
8, methoxy-butoxy modified melamine resin such as Cymel 235 (manufactured by Mitsui Cyanamid); imino type melamine resin such as Cymel 327 and Cymel 328 (manufactured by Mitsui Cyanamid); Cymel 370 (manufactured by Mitsui Cyanamid)
Examples thereof include methylol-modified melamine resins and mixed-modified melamine resins thereof.

As the curing agent of the present invention, an imino or methylol modified or mixed modified melamine resin is preferable. 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.

The amount of at least one of the oxazoline compound and the melamine resin is the amount of at least one of the water-soluble alkyd resin and the water-soluble acrylic resin 10
It is 10 to 200 parts by weight with respect to 0 parts by weight. If it is more than 200 parts by weight, the curing agent remains unreacted, which causes softening of the cured film, lowering of glass transition temperature, lowering of adhesion, and lowering of water corrosion resistance, and if it is less than 10 parts by weight, curing becomes poor. More preferably, it is 20 with respect to 100 parts by weight of the resin.
~ 100 parts by weight.

In the present invention, it is selected from the group consisting of benzenesulfonic acid derivatives, amine salts and ammonium salts thereof, naphthalenesulfonic acid derivatives, amine salts and ammonium salts thereof, and acidic phosphoric acid amine salts and ammonium salts. A strong acid catalyst consisting of at least one of

Amines and ammonium are preferable as the cations forming the salt of the strong acid catalyst, because they are volatilized during the heat curing of the coating film and hardly remain in the coating film. 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 strong acid catalyst include dodecylbenzene sulfonic acid, dinonylnaphthalene sulfonic acid, ammonium dihydrogen phosphate, ammonium monohydrogen phosphate, Catalyst 5
00 (Mitsui Cyanamid), Catalyst 600
(Same), Catalyst 4040 (Same), and the like.

In the present invention, the above-mentioned aqueous coating composition is applied as it is or with an appropriate additive added thereto, as an anticorrosion primer composition, a lubricating anticorrosion coating composition and an automotive anticorrosion coating composition.

When the anticorrosive primer composition or the lubricating anticorrosive coating composition is used, the conductivity of an aqueous dispersion prepared by dispersing 1 g of pigment in 100 g of deionized water in the aqueous coating composition is 600 μS / A rust preventive pigment having a size of not more than cm and finely divided silica are added.
The rust preventive pigment and the silica are at least 1
Add seeds. If the added amount is too small, the effect as a pigment cannot be exhibited, and if the added amount is too large, the effect of the present invention cannot be obtained. Therefore, the total amount of the resin varnish and the curing agent is 100 parts by weight based on the solid content. It is 1 to 40 parts by weight.

Examples of the above-mentioned rust preventive pigments include calcium phosphate (eg, LF Bosei CP-Z manufactured by Kikuchi dye company), phosphate-based rust preventive pigments such as zinc phosphate; zinc molybdate (eg, Kikuchi dye company). LF Bosei M-PSN manufactured by Honjo Chemical Co., Ltd., and Mori White 101) manufactured by Honjo Chemical Co., Ltd .;

Examples of the rust preventive pigment having a conductivity of more than 600 μS / cm include calcium leadate, silica phosphate, and the like.
Examples thereof include zinc chromate, strontium chromate, and barium metaborate. These cannot be used because they not only impair the water resistance and blister of the coating film but also impair the stability of the water-soluble resin. In addition, lead-based rust preventive pigments such as basic lead sulfate and cyanamide lead cannot be used in the present invention except in special cases from the viewpoint of toxicity.

The above aqueous coating composition of the present invention having a substantial acid value of 31 to 100 is added with a certain amount of a rust preventive pigment having an electric conductivity of 100 μS / cm or less to form a composition. Once prepared, it is more suitable as an anticorrosion primer composition. The above conductivity is 1
Examples of the rust preventive pigment having a concentration of 00 μS / cm or less include:
Zinc phosphate (LF Bosei ZP-53Z, manufactured by Kikuchi Dye Company,
LF BOSEY ZP-ZPF), aluminum tripolyphosphate (K white manufactured by Teika Co., Ltd.) and the like can be mentioned.

The above-mentioned water-soluble alkyd resin or water-soluble acrylic resin has a substantial acid value of 31-100 and a hydroxyl value of 100-.
By adjusting it to be 200, the hydration stability of the resin is improved. Further, the paint adhering to the coating equipment can be easily washed off with water, and the diluted paint recovered from the overspray in spray painting in the booth water can be easily concentrated and recovered by the ultrafiltration method. Further, the oil length of the above resin is 5 to 45%, and the SP value of the melamine resin is 9.5.
By selecting those having a concentration of ˜10.9, the stability of the mixture of the melamine resin and the water-soluble alkyd resin in water is improved, and the collection by the ultrafiltration method can be performed smoothly.

The above-mentioned silica used in the present invention is in the form of fine particles or colloid such as sol, and it is preferable to use the one which is usually used as an anticorrosive paint, especially as a coating agent for thin film type lubricating anticorrosion steel sheet. However, neutral or alkaline dry silica or colloidal silica whose pH of the aqueous dispersion is 7 to 11 is preferable. Since most dry silica has an acid point in the acidic region of pH 4 to 5, it tends to lower the pH of the resin aqueous solution, so that the resin does not become water-soluble (becomes a dispersion type) and an aqueous coating. When the composition is set to be weakly alkaline, its storage stability becomes poor, which is not preferable. However, this is not the case when the aqueous coating composition is set to be weakly acidic.

Examples of the above-mentioned wet silica include those stabilized in water in a colloidal state. Examples thereof include 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 the present invention is preferably colloidal with a phosphoric acid compound, a molybdenum compound, a boric acid compound or the like. The colloidal particles are mainly composed of silica and aluminum silicate,
It is preferable that these have a high purity and do not contain miscellaneous ions. Examples of the dry aluminum silicate include Aerosil MOX170 (manufactured by Nippon Aerosil Co., Ltd.),
Aerosil MOX80 (same), Aerosil COK84
(The same) can be mentioned. Aluminum silicate or the like can be more efficiently colloidalized than silica alone.

The amount of the above-mentioned dry silica or dry aluminum silicate is preferably 50 to 200 parts by weight, more preferably 100 to 200 parts by weight, based on the total amount of 1000 parts by weight including water.
It is 150 parts by weight. When the amount is less than 50 parts by weight, the colloidalized particles thus obtained are likely to reaggregate, and the corrosion resistance of the coating film formed by the aqueous coating composition containing the colloidalized particles is lowered, which is not preferable. On the other hand, when the amount exceeds 200 parts by weight, the corrosion resistance of the coating film formed by the aqueous coating composition containing the colloidalized particles thus obtained tends to decrease, which is not preferable.

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 these alkali metal salts and alkaline earth metal salts, the incorporation of metal ions has a detrimental effect on the corrosion resistance of the coating film formed by the aqueous coating composition using the obtained colloidalized particles. Exert. That is, if the coating film 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 extreme corrosion resistance. The use of alkali metal salts or alkaline earth metal salts is not preferred, as it will decrease.

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, and silicic acid compounds such as orthosilicic acid. , Metasilicic acid and the like. 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 is 500 nm or less. In the case of using silica or aluminum silicate, preferably 2 ×
10 ^{−4 to} 2 × 10 ⁰ mol, more preferably 2 × 10 ⁻³ to
A range of 2 × 10 ^-2 mol is preferred. 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. In the case of more than 2 × 10 ⁰ mol it is not preferable because the corrosion resistance of the coating film formed by the aqueous coating composition containing the thus obtained colloidal particles tends to decrease.

The water which is the main component of the colloidal particles is preferably ion-exchanged water or pure water having a small amount of impurities. The amount of water is preferably 950 to 800 parts by weight based on the total amount of 1000 parts by weight of dry silica or dry aluminum silicate and water.

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

The above-mentioned lubricating and anticorrosive coating composition according to the present invention is more preferable by adding 3 to 15 parts by weight of wax in terms of solid content to 100 parts by weight of the total amount of the resin and the curing agent. Can be 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 (average molecular weight of 2000 to 8000).
Examples of polyethylene waxes from Kusumoto Kasei Co., Ltd. Disparon SE210-15T, and company Disparlon SE48
0-10T, Chemipearl WF640 manufactured by Mitsui Oil Co., Ltd., Chemipearl W700 manufactured by the same company, polypropylene wax,
Examples thereof include polybutene wax. Also,
In addition to the above waxes, polytetrafluoroethylene, other fluorine resins, fluorine-based solid lubricants such as carbon fluoride, graphite, metal soap, and the like that can be mixed in the water-based composition can be used.

With respect to the composition obtained by adding the above silica to the above aqueous coating composition and further adding the above wax,
By adding the melamine cyanurate compound, the anticorrosive coating composition for automobiles according to the present invention can be produced. The amount of melamine cyanurate added is
The amount is 0.05 to 25 parts by weight based on 100 parts by weight of the total solid content of the aqueous coating composition, silica and wax. If the amount of melamine cyanurate added is less than 0.05 parts by weight, the effect of preventing the adhesion failure at the interface of the base metal due to the electrical load during electrodeposition coating will disappear as described below, and if it exceeds 25 parts by weight. In the case of thin film coating, the uniformity and denseness of the film are lost and the barrier effect is impeded.

The above melamine cyanurate is a compound having an isocyanur ring-containing plane 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 referred to as “cyanuric acid”) and its tautomer, and in the solid state, melamine molecule and cyanuric acid molecule are It is presumed that they are adjacent to each other in a weak hydrogen bond state alternately and form crystals having the following planar structure.

[0049]

[Chemical 2]

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.

[0051]

[Chemical 3]

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 M manufactured by Nissan Chemical Industries, Ltd.
C series (MC-FW, MC-PW, MC-BW, M
C-UW, MC-420, MC-520, MC-600
Etc.) are commercially available. It is described in JP-A-3-28277 that the melamine cyanurate is contained in a clear layer to exhibit the same pearly luster as that of mica coating in metallic coating of automobiles and the like, but it is not related to the present invention. is there.

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. This means that under cationic electrodeposition coating, the bottom of the electrodeposition coating film is exposed to about pH 12. Therefore, the rust preventive coating composition for automobiles containing the melamine cyanurate compound of the present invention is subjected to electrical load during electrodeposition. There is an effect of preventing the adhesion failure at the interface of the base metal due to.

The melamine cyanurate compound is poorly soluble in water and has heat resistance. Further, 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. This does not dissolve in water penetrating under the coating film during electrodeposition coating and does not become a factor for inhibiting electrodeposition.

To the aqueous coating composition of the present invention, the following pigments, additives and the like can be further added as other components within the range not inconsistent with the constitution of the present invention.

Examples of the rust preventive pigment include titanium oxide,
Phthalocyanine blue, phthalocyanine green, quinacridone, indanthrone, perylene, anthrapyrimidine, carbon black, benzimidazolane, graphite,
Examples include yellow iron oxide and red iron oxide. Examples of extender pigments include calcium carbonate, gypsum, clay, talc and the like. The content of the pigment is 0.5 to 30 with respect to 100 parts by weight of the resin solid content of the aqueous coating composition.
It is preferable to set in the range of parts by weight.

The solvent which can be used in the present invention includes water, alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol, butyl alcohol, isobutyl alcohol, 2-butyl alcohol, benzyl alcohol, 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.

The amount of the above solvent added is in the range of 50 to 80% by weight in the case of water and 0 to 80% by weight in the case of a hydrophilic organic solvent in the aqueous coating composition. The amount is adjusted in the range of 20 to 50% by weight based on the resin solid content of the aqueous coating composition at the time of production, and 10 to 20% by weight based on the resin solid content of the aqueous coating composition at the time of coating. It is preferable.

Further, additives usable in the present invention include antifoaming agents, leveling agents, anti-repellent agents, gloss improvers, anti-settling agents, wetting agents (surfactants), lubricants, preservatives, Examples include dustproofing agents.

For mixing the respective components, an apparatus such as a paint shaker, a dispa, a ball mill, a sand grind mill, a kneader, a dissolver or the like which is commonly used in the production of paint is used, and the viscosity is adjusted by using water as a solvent. On this occasion,
A hydrophilic organic solvent can be used in combination with water as long as the emulsion is not destroyed.

The addition of the colloidalized particles to the aqueous coating composition is carried out in the production process of the coating material (pre-addition) or the completed coating material (post-addition), and the addition amount is the resin of the aqueous coating composition. The amount is 15 to 60 parts by weight, preferably 20 to 40 parts by weight, based on 100 parts by weight of the solid content. When the amount of the colloidalized particles added is less than 15 parts by weight, the corrosion resistance is poor, and when it exceeds 60 parts by weight, the viscosity of the aqueous coating composition is excessively increased, which hinders the manufacturing process, and the pick-up property is increased. In this respect, a roping phenomenon occurs and dilution is required, which is not preferable.

The colloidalized particles are added to the aqueous coating composition by using a dispersion mixing device such as the paint shaker, disper, ball mill, sand grind mill, kneader and dissolver.

Further, it is advantageous to pre-treat the metal plate to be coated in advance before coating in order to prevent the material from rusting and improve the adhesion of the coating. As the pretreatment, degreasing treatment such as acid and alkali washing is generally used.
Further, there is also a chemical conversion treatment method using a chemical conversion liquid such as a phosphate type or chromate type subsequently. In particular, it is known that a series of pretreatments can stably form a coating film having excellent adhesion and rust prevention.

The pre-treated article to be coated is coated with the aqueous coating composition of the present invention in an amount of 0.2 to 5 μm (when dry),
A coating film is formed, and if necessary, the following (A),
Apply by the method of (B).

(A) A metal material (for example, a galvanized steel sheet) coated with the aqueous coating composition of the present invention is bent or deep-drawn, and then coated. The coating may be performed by undercoating (primer coating) and then topcoating, or simply topcoating. In order to improve the anticorrosion property, it is desirable to apply an undercoat (primer coat) on the formed coating film. The primer coat has a function of protecting the material from corrosive action and imparting adhesion to the surface of the metal plate, the surface treatment film and the top coating film. The thickness of the undercoat coating 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 coating film in the top coating is 7 to 50 μm (when dried). If this coating film has a thickness of less than 7 μm, the undercoat material cannot be concealed due to poor coloring power, and if it exceeds 50 μm, there is a risk of pinhole formation during baking at a high temperature for a short time. Optimum conditions for baking temperature and time are set according to the topcoat paint used.

(B) Cationic or anionic electrodeposition coating (dry film thickness: 15 to 40 μm) is applied on the coating formed by the aqueous coating composition of the present invention, and if necessary, alkyd resin, polyester resin or acrylic resin system. Apply intermediate paint (dry film thickness 20-60μm)
Then, an acrylic resin, polyester resin-based or fluororesin-based topcoat is used as a conventional automotive topcoat. Further, there is also a mode in which a top coat is applied on the anticorrosive primer layer having a normal film thickness (20 μm or more) of the above aqueous coating composition. In that case, use this anticorrosion primer under normal conditions (eg: 140 ° C, 20 minutes).
You can apply a top coat without baking (2 coat 1 bake). The primer layer preferably evaporates water at a temperature below the curing temperature. The conditions are preferably 50 ° C. or higher and 3 minutes or longer. In this case, either a water-based paint or a solvent-based paint can be used as the top coat. As described above, the topcoat can be applied without curing the undercoat (usually wet-on-wet coating), and the primer layer and the topcoat layer can be finished by one baking without insufficient curing.

As a coating system to be combined with the coating film formed by the aqueous coating composition of the present invention,
The type of resin is not limited to the above, and may be any of organic solvent type, water type, and powder type.

The method of coating the aqueous coating composition is not particularly limited, and a usual coating method such as air spray coating, airless coating, electrostatic coating or the like can be used.

The lubricating anticorrosion coating composition and the automotive anticorrosion coating composition of the present invention are diluted with water to a concentration suitable for coating, and sprayed, shower coated, followed by roll squeezing, roll coating, dipping and subsequent rolls. A cold-rolled steel sheet, a zinc- or zinc-based plated steel sheet, a zinc alloy-based plated steel sheet, an aluminum-based plated steel sheet, etc. having a dry film weight of 0.3 to 5 g / m ² and a glass transition temperature of the dry film by a method such as drawing. Is applied at 40 ° C or higher,
By drying at 200 ° C. for 15 seconds, a lubricated anticorrosive surface-treated steel sheet can be manufactured.

[0071]

In the aqueous coating composition of the present invention, hydration stability and reactivity with an oxazoline compound can be maintained by limiting the acid value of the water-soluble alkyd resin and the water-soluble acrylic resin. In addition, by limiting the hydroxyl value of the above resin, hydration stability and reactivity with the melamine resin, adhesiveness with the metal substrate is maintained, and a strongly adhered film is realized, which results in corrosion resistance and advanced processing. (Peeling resistance of processed part) can be maintained. By using the oxazoline compound, it is possible to react with the carboxylic acid groups of the resin to crosslink and form a tough film even by baking for a short time. This makes it possible to exhibit corrosion resistance and high workability. When the melamine resin and the oxazoline compound are used in combination, the hydroxyl group of the melamine resin and the oxazoline compound are reacted and cured with the carboxylic acid group of the resin to form a strongly adhered film.

[0072]

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 to these.

Resin Production Example 1 A container equipped with a stirrer, a temperature controller and a decanter was charged with the raw materials having the following compositions and heated with stirring. Soybean fatty acid 30 parts by weight Trimethylolpropane 17 parts by weight Neopentyl glycol 13 parts by weight Trimellitic anhydride 7 parts by weight Isophthalic acid 32 parts by weight Xylene 1 part by weight Dibutyltin oxide 0.02 parts by weight Water produced as the reaction proceeds xylene Was removed by azeotropic distillation, and heating was continued until the acid value became 30 and the hydroxyl value became 60, and the reaction was terminated. The obtained resin was diluted with butyl cellosolve to a nonvolatile content of 70% by weight to obtain an alkyd resin varnish. This resin varnish has a Gardner viscosity Z
₂ , the SP value was 10.37. This resin varnish was theoretically 100% neutralized with triethylamine and adjusted to a nonvolatile content of 40% by weight with deionized water to obtain a water-soluble alkyd resin varnish A.

Resin Production Example 2 A raw material having the following composition was charged into the reaction vessel of Resin Production Example 1 and heated with stirring. Soybean fatty acid 34 parts by weight Trimethylolpropane 31 parts by weight Neopentyl glycol 13 parts by weight Trimellitic anhydride 9 parts by weight Isophthalic acid 25 parts by weight Xylene 1 part by weight Dibutyltin oxide 0.02 parts by weight Water produced as the reaction proceeds xylene Was removed by azeotropic distillation with, and heating was continued until the acid value became 50 and the hydroxyl value became 125 to terminate the reaction. Subsequent processing was carried out in the same manner as in Resin Production Example 1 to obtain a water-soluble alkyd resin varnish B.

Resin Production Example 3 Using the same raw materials as the water-soluble alkyd resin varnishes A and B,
Adjusting the molar ratio of acid and alcohol components and reaction time,
According to a conventional method, water-soluble alkyd resin varnishes C to H having the acid value and the hydroxyl value shown in Table 1 were obtained.

Resin Production Example 4 The reaction vessel of Resin Production Example 1 was charged with raw materials having the following compositions and heated with stirring. Soybean fatty acid 1.8 parts by weight Trimethylolpropane 15 parts by weight Neopentyl glycol 13 parts by weight 1,6-hexanediol 30 parts by weight Trimellitic anhydride 11 parts by weight Isophthalic acid 42 parts by weight Xylene 1 part by weight Dibutyltin oxide 0.02 parts by weight Part Water produced along with the progress of the reaction was azeotropically removed with xylene, and heating was continued until the acid value was 50 and the hydroxyl value was 125, and the reaction was terminated. Subsequent processing was carried out in the same manner as in Resin Production Example 1 to obtain a water-soluble alkyd resin varnish I.

[Measurement of Physical Properties of Water-Soluble Alkyd Resin Varnish] The acid value, hydroxyl value, SP value, amount of low-molecular acid component and substantial acid value of the above water-soluble alkyd resin varnishes A to I were measured and shown in Table 1. Indicated.

The SP value was measured as follows. 0.5 g of the water-soluble alkyd resin varnish was weighed in a 100 ml beaker, and 10 ml of a good solvent such as dioxane or acetone was added and dissolved by stirring. A poor solvent such as n-hexane and deionized water was dropped using a 50 ml buret, and the point at which turbidity occurred was defined as the dropping amount. The measurement was performed at 20 ° C. For the SP value, a numerical value such as the dropping amount is used, and the SP value is determined by reference (J. Polymer S).
Science, A-1, Vol. 5, pp. 1671-1681.
Page) and calculated.

The amount of low molecular weight acid component was measured as follows. Water-soluble alkyd resin varnish with water / butyl cellosolve = 98
A dilution solvent of / 2 was added to adjust the nonvolatile content to 3%. This was subjected to ultrafiltration (UF). "EW4026" (manufactured by Desalination Systems) was used as the ultrafiltration membrane, and the operation was continued at 25 to 30 ° C until the nonvolatile content reached 25%. The amount of filtrate generated during this period and its nonvolatile content were measured. It was confirmed by IR and liquid chromatography that the components appearing in the filtrate were low-molecular acid components and residual monomers generated by hydrolysis during storage of the water-soluble alkyd resin varnish. The amount of low molecular weight acid component was defined as the ratio of parts by weight of non-volatile components in the filtrate when the amount of original resin was 100 parts by weight.

The actual acid value was measured as follows. The acid value of the water-soluble alkyd resin varnish remaining on the ultrafiltration membrane was measured in the course of the operation of measuring the amount of the low molecular acid component, and this was defined as the substantial acid value. This shows the acid value due to the carboxyl group bonded to the alkyd resin polymer.

[0081]

[Table 1]

Examples 1 to 6 and Comparative Examples 1 and 2 Water-soluble alkyd resin varnish C was mixed with titanium oxide, silica, a rust preventive pigment and a curing agent in the proportions shown in Table 2 to prepare aqueous coating compositions. did. The unit of numerical values in Table 2 is parts by weight. As the titanium oxide, Taipaque R9
30 (made by Ishihara Sangyo Co., Ltd.) was used. Nipseal 170 (manufactured by Nippon Silica Co., Ltd.) was used as the silica. In the above anticorrosion pigment, in Table 2, A is LF Bosei CP-Z
(Kikuchi dye company, calcium phosphate type, conductivity 270μ
S / cm), B is LF Bosei PM300C (Kikuchi dye company, aluminum phosphomolybdate system, conductivity 17μ
S / cm) and C represent K White 84S (manufactured by Leica, aluminum tripolyphosphate, conductivity 14 μS / cm). As the curing agent, a melamine resin manufactured by Mitsui Cyanamid Co., Ltd .: Cymel 236, Cymel 238,
Cymel 303, Cymel 328, Cymel 232, oxazoline compound manufactured by Nippon Shokubai Co., Ltd .: Epocros K103
0E and Epocros K1050E were used. Catalyst 500 (manufactured by Mitsui Cyanamid) and ammonium monohydrogen phosphate were used as catalysts.

The coating compositions of Examples 1 to 6 and Comparative Examples 1 and 2 obtained as described above were diluted with water in an NK # 2 cup for 50 seconds, and this was diluted with a zinc phosphate treated plate ( Sprayed on Japan Test Panel Co., Ltd. (0.8 mm thickness) so that the dry film thickness is 25 to 30 μm.
Preheated at 0 ° C. for 3 minutes. On top of this, water-based paint Oudeselect 500 (manufactured by Nippon Paint Co., Ltd.) is dried to a film thickness of 2
It was sprayed to 0 μm and baked at 160 ° C. for 20 minutes. The boiling water resistance (0.5 hours) and the humidity resistance (50 ° C., 95% RH, 100 hours) of this coating film were measured. Further, this coating film was subjected to a salt water spray test for 600 hours to evaluate the peeling of the coating film at the cross cut. The results are shown in Table 2.

In Table 2, the evaluation in the items of boiling water resistance and moisture resistance was as follows. ⊚: Almost no blisters appear. B: Coarse blister (F) by ASTM rating. Δ: Blister is intermediate (M) according to ASTM rating. ×: ASTM rating is blister honey (D or M
D). The evaluation of the peeling of the coating film was as follows. A: No peeling is recognized. A: Peeling width on one side is within 1 mm. Δ: Peeling width on one side within 2 mm. X: Exfoliation width on one side exceeds 2 mm.

[0085]

[Table 2]

Examples 7 and 8 and Comparative Examples 3 and 4 Hydrophobic methoxybutoxy-modified melamine resin Cymel 236 as a curing agent for water-soluble alkyd resin varnishes B and I.
(Manufactured by Mitsui Cyanamid) or methoxybutoxy-modified melamine resin Cymel 235 (manufactured by Mitsui Cyanamid) and dinonylnaphthalenesulfonic acid-based catalyst catalyst 5
00 (manufactured by Mitsui Cyanamide Co., Ltd.) was added in the proportions shown in Table 3 to prepare aqueous coating compositions (9) to (12). In Table 3, the unit of the added amount of each component is parts by weight. The solid content of the water-soluble alkyd resin varnishes B and I is 75%. The above water-based clear paints (9) to (12)
Was diluted with water to adjust the solid content to 20%, and the emulsified state of the water-based clear paint and the particle size of the emulsified resin particles when allowed to stand at 25 ° C. for 2 weeks were examined, and the results are shown in Table 3. The aqueous coating compositions (10) and (12) were diluted with water to adjust the solid content to 3%. These were ultrafiltered and concentrated to a solid content of 20%, the hydration stability of the aqueous coating composition after ultrafiltration was examined, and the results are shown in Table 3.

[0087]

[Table 3]

From Table 3, the water-based clear paint having an oil length of 38 (1
In 0), the emulsion was stably emulsified, but in the water-based clear paint (12) having an oil length of 2, it was found that the emulsion stability was poor.

Examples 9 to 13 Alkyd resin varnishes A, B, C and
To each of E and H, titanium oxide or calcium carbonate as a pigment, methoxybutoxy-modified melamine resin Cymel 236 (manufactured by Mitsui Cyanamid Co., Ltd.) and dinonylnaphthalene sulfonic acid catalyst catalyst 500 (manufactured by Mitsui Cyanamid Co., Ltd.) were added as curing agents. To make aqueous coating compositions (13)-(17). 2 for zinc phosphate treated steel sheet
The above aqueous coating compositions (13) to (17) are applied and baked so that the thickness becomes 0 to 25 μm, and the relative humidity is 9
A humidity resistance test was carried out for 100 hours in an environment of 5% and 50 ° C. Evaluated according to ASTM D-714-56,
Converted to the 10-point method. The evaluation results are shown in Table 4.

[0090]

[Table 4]

As can be seen from Table 4, the amount of low molecular acid component is 4
When it was less than%, the evaluation score was 8 points or more, indicating almost satisfactory performance.

Example 14 An unneutralized alkyd resin varnish B, C, E, F, G, H 20% (solid content) aqueous dispersion was prepared, and when dimethylethanolamine was added dropwise, the solution became transparent. The pH of emulsification was read, and the results obtained by arranging by the actual acid value are shown in FIG. The pH of transparent emulsification is a measure of the water solubility of the alkyd resin varnish, and in the range below this pH, precipitation occurs when the paint or alkyd resin varnish is diluted or stored. The above phenomenon has an important meaning in the stability in water of the paint of the type in which the diluted paint is concentrated and collected by ultrafiltration. In particular, during the ultrafiltration recovery, the amine added for stabilization flows out into the filtrate, and the neutralization rate of the system becomes close to 100% (pH 7.
5) Therefore, if the pH at which the solution becomes transparent is 7.5 or higher, the stability of the coating composition during ultrafiltration and concentration will be poor. It was found that the substance having a substantial acid value of 31 or more is stably present in water even after ultrafiltration.

Example 15 [Production of Lubricant Anticorrosion Coating Composition] For 100 parts by weight (as solid) of the water-soluble alkyd resin varnish C obtained in Resin Production Example 2, the oxazoline compound Epocros K-1050E (Japan) was used as a curing agent. (Manufactured by Catalyst Co., Ltd.) and 30 parts by weight of melamine resin Cymel 328 (manufactured by Mitsui Cyanamid Co., Ltd.), 2 parts by weight of ammonium dihydrogen phosphate as a strongly acidic catalyst, and Adelite AT20N as silica
(Manufactured by Asahi Denka Kogyo Co., Ltd.), the total amount of the water-soluble alkyd resin varnish and the curing agent component is 100 parts by weight, and the solid content is 15
5 parts by weight in terms of solid content of 5 parts by weight of polyethylene wax wax emulsion Emulsion Chemipearl W700 (manufactured by Mitsui Oil Co., Ltd.) as the wax is added to the water-soluble alkyd resin varnish and the curing agent component. A rust coating composition (1) was produced. The amount of each component added is shown in Table 5.

The above lubricating anticorrosive coating composition (1) was diluted with water to a nonvolatile content of 20%, coated on a steel sheet with a bar coater to a dry film thickness of 2 μm, and dried at 150 ° C. for 8 seconds. The ultimate plate temperature was 150 ° C. The steel plate was an electrogalvanized steel plate having a plate thickness of 0.35 mm, which was used after being chromate-treated with NRC300 (manufactured by Nippon Paint Co., Ltd.). Cr adhesion amount is 50 expressed as Cr metal
It was mg / m ² .

With respect to the steel sheet coated with the above-mentioned lubricating anticorrosion coating composition (1), solvent resistance, alkali resistance, cylindrical drawing test, powdering, flat surface corrosion resistance, and quick drying property were examined, and the evaluation results are shown in Table 5. . The solvent resistance was examined by a method in which a gauze containing methyl ethyl ketone was pressed against the coated surface under a load of 300 g and rubbed 10 times to observe changes in the coated surface. The evaluation was according to the following. A: No peeling occurred. ◯: Only a part peeled off. Δ: The peeling was intermediate between ○ and ×. X: About 1/2 of the coated surface was peeled off. XX: The entire coated surface was peeled off.

The alkali resistance was examined by a method of observing a change in the coated surface when immersed in an alkaline degreasing agent Surf Cleaner 53S (manufactured by Nippon Paint Co., Ltd.) at 45 ° C. for 10 minutes. The evaluation was according to the following. A: There was no abnormality. ◯: Whitening was observed in a very small part. Δ: The intermediate area between ○ and × was whitened. X: About half of the coated surface was whitened. XX: The entire surface was whitened.

The evaluation of the cylindrical drawing test was carried out by observing the scratches on the coated surface of the processed part during the cylindrical drawing process according to the following criteria. ⊚: No abnormality. ◯: Scratches were observed on only a part. X: Several scratches were observed. XX: Cracks and galling were observed. The generation of powder (powdering) due to the peeling of the film in the processed part was evaluated according to the following. ⊚: No abnormality. ○: A small part is pulverized. ×: Powder in the middle part between ○ and XX. XX: The entire processed portion was pulverized.

The flat portion corrosion resistance was evaluated by performing a salt spray test (SST) for 800 hours in accordance with JIS-2371 and observing rust on the coated surface. The evaluation was according to the following. A: There was no abnormality. ◯: White rust was observed in a small part. Δ: White rust was observed in an area intermediate between ○ and ×. X: White rust was observed in an area of about 1/2 of the coated surface. XX: White rust was observed on the entire surface.

The quick-drying property was evaluated by measuring the baking time required until peeling of the coated surface was not observed when rubbing was repeated 10 times in the above methyl ethyl ketone rubbing test.

Examples 16 and 17, Comparative Examples 5 and 6 Aqueous lubricating anticorrosive coating composition (2) was prepared in the same manner as in Example 15 except that the amounts of the curing agent and the catalyst were changed as shown in Table 5. ~ (5) was manufactured and the coated surface when coated on a steel sheet was evaluated. The evaluation results are shown in Table 5.

[0101]

[Table 5]

[0102]

By applying the aqueous coating composition of the present invention to a steel sheet, it is possible to obtain a coating excellent in curability and firmly adhered to a metal sheet by baking at low temperature for a short time. The steel sheet surface-treated with the water-based coating composition has excellent corrosion resistance, water resistance, etc., and has lubricity, weldability, and conductivity suitable for electrodeposition coating.
The occurrence of powdering during processing is prevented. The water-based coating composition of the present invention can be used as an anticorrosion primer composition in a wet-on-wet two-coat one-bake coating method, and has a lubricating property and a rust preventive property suitable for high-level processing such as deep drawing. It can be used as a lubricating anticorrosive coating composition or an anticorrosive coating composition for automobiles.

[Brief description of drawings]

FIG. 1 is a water-soluble alkyd resin (B, C, E, F, G,
The relationship between the water solubility of H) and the substantial acid value is shown. The vertical axis represents the pH at which the liquid crystal becomes transparent, and the horizontal axis represents the substantial acid value.

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] March 4, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0101

[Correction method] Change

[Correction content]

[0101]

[Table 5]

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C09D 5/08 PQE 133/08 PGG 161/28 PHK (72) Inventor Keita Mizutani Ikeda, Neyagawa, Osaka Nakamachi 19-17 No. 17 Japan Paint Co., Ltd. (72) Inventor Tetsuro Ibino 19-17 Ikedanaka-cho, Neyagawa-shi, Osaka Prefecture Japan Paint Co., Ltd. (72) Inventor Kazuo Uenoyama 19-Ikedanaka-cho, Neyagawa-shi, Osaka No. 17 within Japan Paint Co., Ltd.

Claims (10)

[Claims] 1. An acid value of 25 to 100 and a hydroxyl value of 35.
-200, 100 parts by weight of a resin varnish consisting of at least one of a water-soluble alkyd resin and a water-soluble acrylic resin having an SP value of 10.0 to 11.0, an oxazoline compound and a melamine resin having a curing start temperature of 140 ° C. or less. Hardener 1 consisting of at least one of these
0 to 200 parts by weight, at least selected from the group consisting of benzenesulfonic acid derivatives, amine salts and ammonium salts thereof, naphthalenesulfonic acid derivatives, amine salts and ammonium salts thereof, and acidic phosphoric acid amine salts and ammonium salts. An aqueous coating composition comprising 0.5 to 5 parts by weight of a strongly acidic catalyst consisting of one kind. 2. The aqueous coating composition according to claim 1, wherein the water-soluble alkyd resin and the water-soluble acrylic resin have a hydroxyl value of 100 to 200. 3. The filtrate when the water-soluble alkyd resin and the water-soluble acrylic resin are theoretically 100% neutralized and the nonvolatile content is diluted to 3%, and then the nonvolatile content is concentrated to 20% by ultrafiltration. The aqueous coating composition according to claim 1, wherein the resin component comprises 4% or less of the original resin. 4. A water-soluble alkyd resin and a water-soluble acrylic resin are theoretically 100% neutralized, and after the nonvolatile content is diluted to 3%, the nonvolatile content is concentrated to 20% by ultrafiltration. The aqueous coating composition according to claim 1, wherein the acid value of the recovered resin varnish is 31 to 100. 5. The aqueous coating composition according to claim 1, wherein the melamine resin is at least one of imino type and methylol type. 6. The aqueous coating composition according to claim 1, wherein 1 to 40 parts by weight of at least one kind of rust preventive pigment having a conductivity of 600 μS / cm or less and fine particle silica is added. An anticorrosive primer composition or a lubricating anticorrosive coating composition. 7. An anticorrosion primer composition comprising the aqueous coating composition according to claim 1 and 1 to 10 parts by weight of a rust preventive pigment having an electric conductivity of 100 μS / cm or less. 8. The water-soluble alkyd resin and the water-soluble acrylic resin have SP values of 9.5 to 10.9, and the melamine resin is a methoxybutoxy-modified melamine resin.
The anticorrosion primer composition described. 9. A lubricating anticorrosion coating composition comprising 100 parts by weight of the lubricating anticorrosion coating composition according to claim 6 and 3 to 15 parts by weight of wax. 10. A melamine cyanurate compound of 0.05 to 25 relative to 100 parts by weight of the total solid content of the composition obtained by adding 2 to 10 parts by weight of wax to 100 parts by weight of the lubricating and anticorrosive coating composition according to claim 6. An anticorrosive coating composition for automobiles, which is characterized by adding parts by weight.