JPH05309331A - Composite coated aluminum in sheet or aluminum alloy sheet excellent in press molding property, resistance against scratching and finely rusting, and in brilliancy - Google Patents

Abstract

PURPOSE:To ensure that superb brilliancy and excellent press molding properties are obtained on an aluminum sheet or an aluminum alloy sheet by providing a specified amount of chromate layer on their surfaces and a specified organic film on the chromate layer. CONSTITUTION:This composite coated aluminum sheet or aluminum alloy sheet having excellent press molding properties and resistance against scratch and rust as well as superb brilliancy consists of 1 to 150mg/m<2> of chromate layer in terms of metal chrome as the first layer, formed on an aluminum sheet or an aluminum alloy sheet. In addition, the sheet has 0.05 to 2mum thickness of an organic film containing a block urethane modified epoxy resin and a lubricant composed of 30 to 80wt.% of the block urethane modified epoxy resin and 5 to 60wt.% (wt.% of volatile part) lubricant as the second layer formed on the first layer. Thus, the sheet is almost free from scratch when it is handled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum plate or an aluminum alloy plate which is used for automobile bodies, home electric appliances and the like, and which is excellent in press formability, scratch resistance, yarn rust resistance and sharpness. ..

[0002]

2. Description of the Related Art Conventionally, steel sheets have been widely used for automobile bodies. However, in recent years, there has been a strong demand for drastic weight reduction of automobile bodies for the purpose of improving the fuel efficiency of automobiles in order to protect the global environment. became. Based on such a background, an aluminum plate for an automobile body, which is an alternative to a steel plate, in particular, an aluminum alloy plate has been actively developed, and is already being adopted in some automobiles. Even when aluminum alloy plate is applied to the car body, press formability similar to steel plate,
Workability (eg scratch resistance during handling), quality characteristics after painting (eg thread rust resistance, image clarity, paint adhesion)
However, when an aluminum alloy sheet is used as it is, sufficient quality characteristics (for example, press formability, scratch resistance, and thread rust resistance) cannot be obtained when compared with a steel sheet.

Conventionally, as a method for improving the press formability and the thread rust resistance of an aluminum alloy plate, a method of forming a chromate layer on the surface of the aluminum alloy plate and forming an organic resin film on the chromate layer (Japanese Patent Laid-Open No. 3-3003). 140480
No.) is proposed. Further, although not an aluminum alloy plate, as a method for improving the formability of a steel plate, a method of forming a chromate layer on the surface of the steel plate and forming an organic resin film containing a fluororesin and silica on the upper layer thereof (Patent Document 1) No. 63-162886), a method of forming a phosphate film or a chromate layer on the surface of a steel sheet, and forming a resin film containing a conductive substance, a chromium compound and a lubricant on the upper layer (JP-A-63-83172). No.) is proposed.

[0004]

However, in the method disclosed in Japanese Patent Laid-Open No. 3-140480, although it is possible to improve the thread rust resistance, since the organic film does not contain a lubricant, press molding is performed. There is a problem that the image forming property is insufficient, and the image clarity and the weldability are also insufficient. Further, when the method disclosed in JP-A-63-162886 is applied to an aluminum alloy plate, it is possible to improve press formability, but a carboxylated polyolefin resin is used as a binder for an organic film. Since it is used, the adhesion to the cationic electrodeposition coating applied to the car body is insufficient, and the image clarity and weldability are also insufficient. Further, according to the method disclosed in JP-A-63-83172, although the organic coating contains a conductive substance, good weldability can be obtained, but an epoxy resin having relatively strong hydrophobicity is used as a binder for the organic coating. Therefore, there is a problem in that the image clarity is insufficient, and because a wax-based lubricant is used, the press moldability is not sufficient.

The present invention has been made in order to solve the above problems, and when applied to an automobile body, the plate is less scratched during handling, and excellent moldability is obtained in the pressing process. Further, it is an object of the present invention to provide a composite-coated aluminum plate or aluminum alloy plate having excellent outer surface rust resistance and high image clarity on the outer surface side of the vehicle body outer plate.

[0006]

In order to achieve such an object, the inventors of the present invention have made extensive studies on the coating composition to be applied to aluminum plates and aluminum alloy plates, and have obtained the following findings. Improve the press formability by adding a lubricant such as fluororesin, graphite, and boron nitride to the organic film, and imparting lubricity to the surface. The chromate film as the underlying film suppresses thread rust and The effect becomes even more remarkable by adding rust preventive additives such as silica and chromate to the organic film. Weldability deteriorates by forming an organic film on the surface of the aluminum plate or aluminum alloy plate. However, by adding a conductive substance to the organic film, the weldability is improved.To achieve high corrosion resistance and adhesion with cationic electrodeposition paint, the epoxy resin is modified with a polyfunctional amine and monoisocyanate. It is effective to introduce polyethylene glycol into block urethane as a curing agent to form an organic film. Appropriate hydrophilicity is imparted, and by promoting the deposition of a uniform electrodeposition coating film over the entire surface, a smooth electrodeposition coating film is obtained, and excellent image clarity is ensured. It has been made, and is characterized by having the following configuration.

[1] A surface of an aluminum plate or an aluminum alloy plate has a chromate layer as a first layer in the range of 1 to 150 mg / m ^{2 in} terms of metal chromium, and a second layer above the chromate layer as a second layer, in the following proportion, a block urethane-modified epoxy A composite-coated aluminum plate or aluminum alloy plate having an excellent press-formability, scratch resistance, yarn rust resistance, and sharpness, which has an organic film having a film thickness of 0.05 to 2 μm containing a resin and a lubricant. Block urethane-modified epoxy resin: 30-80 wt% Lubricant: 5-60 wt% However, weight% of non-volatile content

[2] On the surface of an aluminum plate or an aluminum alloy plate, a chromate layer as a first layer is contained in an amount of 1 to 150 mg / m ^{2 in} terms of metallic chromium, and a second layer above it is a block urethane-modified epoxy having the following ratio. A composite coated aluminum plate having an organic film having a film thickness of 0.05 to 2 μm containing a resin, a lubricant and an anticorrosive additive and having excellent press moldability, scratch resistance, yarn rust resistance and sharpness. Or aluminum alloy plate. Block urethane modified epoxy resin: 30 to 80 wt% Lubricant: 5 to 60 wt% Rust preventive additive: 3 to 50 wt% However, weight% of non-volatile content

[3] A chromate layer as a first layer having a chromate layer of 1 to 150 mg / m ^{2 on the} surface of an aluminum plate or an aluminum alloy plate, and as a second layer above the chromate layer, a block urethane-modified epoxy having the following ratio is used. A composite coated aluminum plate having an organic film having a film thickness of 0.05 to 2 μm containing a resin, a lubricant and a conductive substance, which is excellent in press formability, scratch resistance, thread rust resistance and sharpness, or Aluminum alloy plate. Block urethane modified epoxy resin: 30 to 80 wt% Lubricant: 5 to 60 wt% Conductive substance: 2 to 40 wt% However, weight% of non-volatile content

[4] On the surface of an aluminum plate or an aluminum alloy plate, a chromate layer as a first layer is contained in an amount of 1 to 150 mg / m ^{2 in} terms of metallic chromium, and a second layer is provided thereon as a second layer in the following proportions of a block urethane modified epoxy Film thickness 0.0 including resin, lubricant, rust preventive additive and conductive material
A composite-coated aluminum plate or aluminum alloy plate having an organic film of 5 to 2 μm, which is excellent in press formability, scratch resistance, yarn rust resistance and sharpness. Block urethane modified epoxy resin: 30 to 80 wt% Lubricant: 5 to 60 wt% Rust preventive additive: 3 to 50 wt% Conductive substance: 2 to 40 wt% However, weight% of nonvolatile content

[5] In the aluminum plate or aluminum alloy plate according to the above [1], [2], [3] or [4], the lubricant forming the organic film is fluororesin, graphite and boron nitride. A composite coated aluminum plate or aluminum alloy plate which is excellent in press formability, scratch resistance, yarn rust resistance and image clarity and which comprises one or more lubricants selected from the group consisting of

[6] The above [2], [4] or [5]
In the aluminum plate or aluminum alloy plate according to, the press-formability and scratch resistance of the rust-preventing additive constituting the organic film is one or more rust-preventing additives selected from the group consisting of silica and chromate. Composite coated aluminum plate or aluminum alloy plate with excellent durability, rust resistance and sharpness.

[7] In the aluminum plate or aluminum alloy plate according to the above [6], the rust preventive additive constituting the organic film is composed of the following proportions of silica and chromate, and has press formability and scratch resistance. , Composite coated aluminum plate or aluminum alloy plate with excellent thread rust resistance and sharpness. Silica / chromate = 90/10 to 10/90 (weight ratio)

[8] The above [1], [2], [3],
In the aluminum plate or aluminum alloy plate according to [4], [5], [6] or [7], a modified epoxy resin in which a block urethane-modified epoxy resin forming an organic film is modified with a polyfunctional amine. Resin (A)
In contrast, block urethane (B) consisting of polyethylene glycol, polyisocyanate and blocking agent is
/ B = 95/5 to 50/50 mixed by weight (weight ratio) is a block urethane-modified epoxy resin, which is a composite coated aluminum plate having excellent press moldability, scratch resistance, yarn rust resistance, and sharpness. Aluminum alloy plate.

[0015]

[9] On the surface of an aluminum plate or an aluminum alloy plate, a chromate layer as a first layer has 1 to 150 mg / m ^{2 in} terms of metallic chromium, and a second layer as a second layer on top of it has a block urethane-modified epoxy resin of 30 to 80 wt%. Lubricant: 5 to 60 wt% However, an organic film having a film thickness of 0.05 to 2 μm, which contains a block urethane-modified epoxy resin in a proportion of non-volatile content by weight and a lubricant, and the block urethane-modified epoxy resin is , A modified urethane resin (A) obtained by modifying an epoxy resin with a polyfunctional amine, and a block urethane (B) composed of polyethylene glycol, polyisocyanate and a blocking agent
B is a block urethane-modified epoxy resin mixed in a ratio (weight ratio) of 95/5 to 50/50, and the lubricant is one or more lubricants selected from the group consisting of fluororesin, graphite and boron nitride. A composite-coated aluminum plate or aluminum alloy plate excellent in press formability, scratch resistance, yarn rust resistance, and image clarity having an organic film.

[10] On the surface of an aluminum plate or an aluminum alloy plate, a chromate layer as a first layer is provided in an amount of 1 to 150 mg / m ^{2 in} terms of metallic chromium, and a second layer is formed as an upper layer.
As a layer, block urethane modified epoxy resin: 30 to 80 wt% Lubricant: 5 to 60 wt% Rust prevention additive: 3 to 50 wt% However, block urethane modified epoxy resin and lubricant and rust preventive agent in a proportion of non-volatile weight% An organic film having a film thickness of 0.05 to 2 μm including an additive, wherein the block urethane-modified epoxy resin is a modified epoxy resin (A) obtained by modifying an epoxy resin with a polyfunctional amine, and polyethylene glycol A block urethane-modified epoxy resin in which a block urethane (B) composed of an isocyanate and a blocking agent is mixed in a ratio (weight ratio) of A / B = 95/5 to 50/50, and the lubricant is a fluororesin, graphite and nitriding. The lubricant comprises one or more lubricants selected from the group consisting of boron, and the rust preventive additive is silica / chromium. Acid salt = 90/10 to 10/90 (weight ratio), which is excellent in press moldability, scratch resistance, yarn rust resistance and sharpness, which has an organic film made of silica and chromate. Composite coated aluminum plate or aluminum alloy plate.

[11] On the surface of an aluminum plate or an aluminum alloy plate, a chromate layer as a first layer is provided in an amount of 1 to 150 mg / m ^{2 in} terms of metallic chromium, and a second layer is formed as an upper layer.
As a layer, block urethane-modified epoxy resin: 30-80 wt% Lubricant: 5-60 wt% Conductive substance: 2-40 wt% However, block urethane-modified epoxy resin, lubricant, and conductive substance in a proportion of non-volatile weight% An organic film having a film thickness of 0.05 to 2 μm including and a modified epoxy resin (A) obtained by modifying the epoxy resin with a polyfunctional amine, wherein the block urethane modified epoxy resin is polyethylene glycol, polyisocyanate and A block urethane-modified epoxy resin in which block urethane (B) composed of a blocking agent is mixed at a ratio of A / B = 95/5 to 50/50 (weight ratio), and the lubricant is fluororesin, graphite and boron nitride. A press formability having an organic film comprising one or more lubricants selected from the group consisting of Composite coated aluminum plate or aluminum alloy plate with excellent scratch resistance, yarn rust resistance and sharpness.

[12] On the surface of an aluminum plate or an aluminum alloy plate, a chromate layer as a first layer is provided in an amount of 1 to 150 mg / m ^{2 in} terms of metallic chromium, and a second layer is provided as an upper layer.
As a layer, block urethane modified epoxy resin: 30 to 80 wt% Lubricant: 5 to 60 wt% Rust preventive additive: 3 to 50 wt% Conductive material: 2 to 40 wt% However, block urethane modified in a proportion of non-volatile content by weight Film thickness containing epoxy resin, lubricant, rust preventive additive and conductive material 0.05 to 2 μm
And a block urethane (B) comprising a polyethylene glycol, a polyisocyanate and a blocking agent, in addition to the modified epoxy resin (A) obtained by modifying the epoxy resin with a polyfunctional amine. A / B = block urethane-modified epoxy resin mixed in a ratio (weight ratio) of 95/5 to 50/50, wherein the lubricant is one or more kinds of lubrication selected from the group consisting of fluororesin, graphite and boron nitride. And an anticorrosive additive having an organic coating film of silica and chromate in the ratio of silica / chromate = 90/10 to 10/90 (weight ratio). Composite coated aluminum plate or aluminum alloy plate with excellent scratch resistance, yarn rust resistance and sharpness.

[13] The above [1], [2], [3],
[4], [5], [6], [7], [8],

[9],
The aluminum plate or aluminum alloy plate according to [10], [11] or [12], wherein the oxide film thickness on the surface of the aluminum plate or aluminum alloy plate is 100 Å or less, press moldability, scratch resistance, and thread rust resistance. Composite coated aluminum plate or aluminum alloy plate with excellent heat resistance and sharpness.

[0020]

The original plates used in the present invention include industrial pure aluminum plates and aluminum alloy plates containing one or more alloying elements such as copper, manganese, silicon, magnesium, zinc, chromium and nickel. There are, for example, JIS 105 as the aluminum plate and the aluminum alloy plate.
0, 1100, 1085, 1200, 2002, 2117, 2036, 2037, 203
8, 3004, 5052, 5182, 6009, 6010, 6015, 6015, 601
There are 6 and 6111 mag. For convenience of description, the pure aluminum plate and the aluminum alloy plate described above are collectively referred to as "aluminum plate" in the description of the "action".

An oxide film having a thickness of about several hundred liters is formed on the surface of the aluminum plate after rolling and annealing, and this oxide film impedes the electrical conductivity when welding the aluminum plate, It is preferable to dissolve / remove it with an alkaline aqueous solution or the like, since the property is remarkably deteriorated. Oxide film thickness is 10
If it is 0 Å or less, good weldability can be secured, and in order to obtain particularly high weldability, the oxide film thickness is preferably 80 Å or less.

The chromate layer formed on the surface of such an aluminum plate has a passivation effect of hexavalent chromium contained in the chromate layer due to chromate ions and trivalent chromium which is a reduction product of chromate ions. The surface of the hydrated chromium oxide film reduces the anode area, and the chromium hydrated oxide film of trivalent chromium serves as a diffusion barrier for water and oxygen, thereby suppressing corrosion of the aluminum plate. The amount of the chromate film deposited is 1 to 150 mg / m ^{2 in} terms of metallic chromium. Adhesion amount is 1m
If it is less than g / m ² , sufficient thread rust resistance cannot be expected, while if it exceeds 150 mg / m ² , weldability deteriorates. Further, in order to obtain higher thread rust resistance and weldability, it is preferably in the range of 5 to 100 mg / m ² .

As the chromate treatment for forming this chromate film, any of reaction type, electrolytic type and coating type methods can be applied. From the viewpoint of yarn rust resistance, a coating type in which the chromate film contains a large amount of hexavalent chromium chromate ions is preferable. In the coating type chromate treatment, a partially reduced chromic acid aqueous solution is used as a main component, and one or more of the following components, if necessary, is added to the aluminum plate to apply a treatment liquid to the aluminum plate, followed by washing with water. Dry without doing. Water-soluble or water-dispersible organic resins such as acrylic resins and polyester resins Silica, alumina, titania, zirconia, and other oxide colloids and / or powders Molybdic acid, tungstic acid, vanadic acid, and other acids and / or salts thereof Phosphorus Phosphoric acids such as acids and polyphosphoric acids Zirconium fluorides, silicofluorides, fluorides such as titanium fluorides, metal ions such as zinc ions, iron phosphide, conductive fine powders such as antimony-doped tin oxide, etc. The treatment liquid is applied by the roll coater method, but it is also possible to adjust the application amount by the air knife method or the roll squeezing method after applying the dipping method or the spray method.

The organic film formed as the second layer on the chromate layer contains a predetermined amount of the block urethane-modified epoxy resin and a lubricant, and is used in a corrosive environment of hexavalent chromate ions in the chromate layer. In addition to suppressing excessive elution into the aluminum plate to maintain the anticorrosion effect, the lubricant can provide good lubrication characteristics of the aluminum plate during press working.
In addition, if necessary, rust resistance such as silica or chromate is added to the organic film to improve the thread rust resistance, and by adding a conductive substance, the organic film has a suitable conductivity. Property is imparted and good weldability is obtained.

As the epoxy resin constituting the urethane-modified epoxy resin, bisphenol A, bisphenol F, novolac or the like glycidyl etherified epoxy resin, bisphenol A propylene oxide or ethylene oxide added glycidyl etherified epoxy resin, etc. Can be used. Further, an aliphatic epoxy resin, an alicyclic epoxy resin, and a polyether-based epoxy resin can be used, and two or more kinds of these epoxy resins can be used in combination. Here, the epoxy equivalent of the epoxy resin is preferably 400 or more from the viewpoint of yarn rust resistance.

The modified epoxy resin is most preferably a modified epoxy resin obtained by modifying the epoxy resin with a polyfunctional amine from the viewpoints of corrosion resistance and adhesion to the cationic electrodeposition coating. A modified epoxy resin is obtained by reacting a glycidyl group of the epoxy resin with a polyfunctional amine. Examples of polyfunctional amines include primary alkanolamines such as ethanolamine, propanolamine, isopropanolamine, butanolamine, etc., primary alkylamines such as propylamine, butylamine, octylamine, decylamine, ethylenediamine, diethylenetriamine, tetraethylenepentamine, xylene. Examples thereof include diamine, aminoethylpiperazine, norbornanediaminomethyl, and the like having two or more active hydrogens in one molecule, and it is also possible to use two or more kinds of these amines in combination. As the polyfunctional amine, alkanolamine is the most preferable from the viewpoint of yarn rust resistance and paint adhesion.

The active hydrogen of the amine is excessive with respect to the glycidyl group, and the active hydrogen of the amine exists in the modified epoxy resin. Then, there is no problem in reacting the active hydrogen with the monoisocyanate, which has the effect of further improving the corrosion resistance. As a synthetic example of the modified epoxy resin, both are mixed so that the active hydrogen of the polyfunctional amine is 1.1 to 1.8 times equivalent to the glycidyl group of the epoxy resin, and they are mixed at 70 to 150 ° C. for 4 to 10 hours. An example is shown in which the reaction is continued, and monoisocyanate is added in an amount of 0.7 to 2.0 times equivalent to the active hydrogen of the remaining amine, and the reaction is continued at 30 to 100 ° C.

The blocked urethane of the present invention is a compound in which an isocyanate group having a high activity of an isocyanate compound is protected by a suitable compound to make it inactive. When heated, the blocking agent is dissociated to easily regenerate the activity of the isocyanate group. It is a thing. That is, it has a role as a curing agent for the modified epoxy resin. By introducing polyethylene glycol into the block urethane, the present inventors imparted an appropriate hydrophilicity to the organic coating, and as a result, water was uniformly permeated into the organic coating during cationic electrodeposition coating, which resulted in a uniform distribution. It has been found that a smooth electrodeposition coating film is deposited and a smooth electrodeposition coating film is obtained. Therefore, as the block urethane, the one in which polyethylene glycol is introduced, that is, the one composed of polyethylene glycol, polyisocyanate and a blocking agent is most preferable.

Polyethylene glycol has the general formula

[Chemical 1] And has a molecular weight of 400 or more. Further, a more preferable molecular weight is 1500 or more. When polyethylene glycol is used, the organic film is given a suitable hydrophilicity, resulting in improved compatibility with cationic electrodeposition paints and a smooth electrodeposited surface, resulting in excellent image clarity after middle and top coats. Sex is obtained.

Examples of polyisocyanates include aliphatic isocyanates such as hexamethylene diisocyanate and trimethylhexamethylene diisocyanate, xylylene diisocyanate, 2,4-tolylene diisocyanate,
Aromatic isocyanates such as 2,6-tolylene diisocyanate, isophorone diisocyanate, alicyclic isocyanates such as norbornane diisocyanate methyl, and mixtures and polynuclear compounds thereof can be used. As a blocking agent, phenolic compounds such as phenol, ε
-A lactam compound such as caprolactam, an oxime compound such as methylethylketoxime, or an imine compound such as ethyleneimine can be used.
It is also possible to use mixtures of more than one species.

In the block urethane, a prepolymer is synthesized by mixing and reacting the polyisocyanate so that the isocyanate group is excessive with respect to the hydroxyl group of the polyol, and the residual isocyanate group of the prepolymer is protected with a blocking agent. It is obtained by doing. The reaction temperature of these is 30 to 100 ° C.

The block urethane-modified epoxy resin of the present invention can be obtained by mixing the above-mentioned modified epoxy resin and block urethane. As described above, as the block urethane modified epoxy resin, a mixture of a modified epoxy resin (A) obtained by modifying an epoxy resin with a polyfunctional amine and a block urethane composed of polyethylene glycol, polyisocyanate and a blocking agent has corrosion resistance,
It is most preferable from the viewpoint of coating adhesion and image clarity, and the mixing ratio in this case is preferably in the range of A / B = 95/5 to 50/50. Ratio of modified epoxy resin (A) is 95/5
If it exceeds, there is a problem that the image clarity after middle and top coating is deteriorated. Further, the ratio of the modified epoxy resin (A) is 50/50.
If it is less than 1, the yarn rust resistance is deteriorated. In order to obtain higher image clarity and yarn rust resistance, A / B = 90/10 to 60/4
A range of 0 is preferred.

The compounding amount of the block urethane-modified epoxy resin in the organic film is 30 to 80 wt%. 30w
If it is less than t%, the function of the resin as a binder becomes insufficient and the organic film becomes brittle, so that the coating adhesion and scratch resistance are poor. On the other hand, if it exceeds 80 wt%, the hydroxyl groups in the block urethane-modified epoxy resin skeleton will adhere to the press mold, deteriorating the moldability. Further, in order to satisfy higher paint adhesion, scratch resistance and press formability, the range of 40 to 70 wt% is preferable.

Next, in the present invention, by adding a lubricant to the organic film, it is possible to prevent the press die and the aluminum plate from adhering to each other and improve the press formability. The amount of lubricant added to the organic film is 5 to 60w
t%. If the amount of lubricant added is less than 5 wt%, sufficient press formability cannot be expected, while 60 wt%
If it exceeds%, the adhesion with the cationic electrodeposition coating composition deteriorates.
Further, in order to satisfy higher press moldability and paint adhesion, a range of 10 to 50 wt% is preferable.

When the lubricant is in the form of particles, its average particle size is preferably in the range of 0.1 to 9 μm. It is considered that the lubricant added to the organic film reduces the friction coefficient of the surface by appropriately exposing it to the surface of the organic film and imparts lubricity to the plate. It cannot be properly exposed on the surface of the film, and press formability deteriorates. On the other hand, when it exceeds 9 μm, the smoothness of the electrodeposition coated surface is deteriorated and the image clarity is deteriorated.

As the lubricant used in the present invention, a fluororesin (eg, tetrafluoroethylene resin, tetrafluoroethylene-hexafluoropropylene copolymer resin, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin, Fine powder of tetrafluoroethylene-ethylene copolymer resin, trifluoroethylene chloride resin, vinylidene fluoride resin), graphite, boron nitride, polyethylene resin, molybdenum disulfide, oil-based lubricant, carbon fluoride, extreme pressure agent, etc. , Liquids, colloids can be used. From the viewpoint of press moldability, fluororesin, graphite, and boron nitride are excellent, and tetrafluoroethylene resin is most preferable among fluororesins.

Next, in the present invention, a rust preventive additive may be added to the organic coating in the range of 3 to 50 wt% for the purpose of improving the thread rust resistance. If the rust preventive additive is less than 3 wt%, the effect of improving the thread rust resistance is insufficient, while on the other hand, 50 wt
%, The film peels off during press molding, degrading moldability. Further, in order to satisfy the higher level of yarn rust resistance and moldability, the range of 5 to 40 wt% is preferable.

As the rust preventive additive used in the present invention, fine powders or colloids of silica, chromate, aluminum dihydrogen tripolyphosphate, aluminum phosphomolybdate, zinc phosphate and the like can be used. From the viewpoint of yarn rust resistance, silica and chromate are preferable. It is presumed that a small amount of silica is dissolved in a corrosive environment, and the silicate ion functions as a film-forming corrosion inhibitor to exert an anticorrosion effect. Further, it is considered that the chromate dissolves in a corrosive environment in a trace amount to release hexavalent chromate ions and suppress the corrosion of the aluminum plate by a mechanism similar to that of the chromate layer.

By adding silica and chromate in combination, it is possible to obtain higher yarn rust resistance. That is, by adding silica and chromate in the organic film in a weight ratio of silica / chromate in the range of 90/10 to 10/90, synergistic effect of anticorrosion effect of both is the most excellent anti-rust property. Sex is obtained. Even if the ratio of silica to chromate exceeds 90/10,
If it is less than 90, the synergistic effect is insufficient and the yarn rust resistance is slightly inferior.

The silica used in the present invention is dry silica (for example, AEROSIL 130 manufactured by Nippon Aerosil Co., Ltd.,
AEROSIL 200, AEROSIL 300, AEROSIL 380, AE
ROSIL R972, AEROSIL R811, AEROSIL R805
Etc.), organosilica sol (for example, MA-ST, IPA-ST, NBA-ST, IBA-manufactured by Nissan Chemical Industries, Ltd.).
ST, EG-ST, XBA-ST, ETC-ST, DM
AC-ST, etc.), precipitated wet silica (for example, T-32 (S), K-41, F-80 manufactured by Tokuyama Soda Co., Ltd.), gel wet silica (for example, Syloid 244 manufactured by Fuji Devison Chemical Co., Ltd.). , Syloid 150, Syloid 72, Syroid 65, SHIELDEX, etc.) can be applied. It is also possible to use a mixture of two or more of the above silicas.

When hydrophobic silica whose surface is made hydrophobic by substituting a silanol group on the silica surface with a methyl group or the like is added to the block urethane-modified epoxy resin,
The compatibility between the organic film and the cationic electro-deposition paint, which is a water-based paint, becomes poor, and a smooth electro-deposition coated surface cannot be obtained, resulting in poor image clarity after middle / top coating. Therefore, in order to obtain excellent image clarity, silica having a non-hydrophobic surface is preferable. Further, in the present invention, as a method for further improving the anticorrosion effect of silica, silica ion-exchanged with a cation having a corrosion-inhibiting action (for example, calcium, zinc, cobalt, lead, strontium, lithium, barium, manganese) is used. Can be used. It is considered that these cations ion-exchange with protons in a corrosive environment and are released from silica to form stable corrosion products on the metal surface and suppress corrosion.

The specific surface area of silica is 20 to 100.
The range of 0 m ² / g (BET method) is preferable. When the specific surface area is less than 20 m ² / g, the effect of improving the thread rust resistance is poor, and the smoothness of the electrodeposition coated surface is reduced and the image clarity is deteriorated. On the other hand, when the specific surface area exceeds 1000 m ² / g, the thixotropy of the coating composition containing silica becomes strong, and the workability at the time of coating with a roll coater or the like decreases.

Chromates used in the present invention include barium chromate (BaCrO ₄ ), strontium chromate (SrCrO ₄ ), and calcium chromate (CaCr).
O ₄ ), zinc chromate (ZnCrO ₄ .4Zn (O
H) ₂ ), zinc potassium chromate (K ₂ O ・ 4ZnO ・ 4
CrO ₃ .3H ₂ O), lead chromate (PbCrO ₄ ) and the like can be used. It is also possible to use a mixture of two or more of the above chromates. However, from the viewpoint of yarn rust resistance, barium chromate and strontium chromate, which are expected to have a self-repairing effect due to hexavalent chromate ions over a long period of time, are preferable. In addition, barium chromate, which has a low solubility in water, is preferable from the viewpoint of minimizing the elution of water-soluble chromium from the chromate added to the organic film in the pretreatment process for coating automobiles. As the average particle size of chromate,
The range of 0.1 to 1 μm is preferable, and if it is less than 0.1 μm, the solubility of chromate in water becomes excessive, so that the self-repairing effect of hexavalent chromate ion is lost, while it exceeds 1 μm. And the smoothness of the electrodeposition coated surface deteriorates and the image clarity deteriorates.

Next, in the present invention, by adding a conductive substance to the organic film, the organic film is provided with appropriate conductivity and the weldability can be improved. The amount of conductive material added to the organic film is 2 to 40 wt%. Two
If it is less than wt%, the electrical conductivity of the organic film is insufficient, so the weldability is somewhat inferior. On the other hand, if it exceeds 40 wt%, the conductive substance in the organic film becomes the starting point of the oxygen reduction reaction in a corrosive environment, and the thread rust resistance Deteriorate. Further, in order to satisfy higher weldability and yarn rust resistance, 3 to 30 wt%
Is preferred. As the average particle diameter of the conductive substance,
The range of 0.01 to 9 μm is preferable, and if it is less than 0.01 μm, it becomes difficult to three-dimensionally contact the particles of the conductive substance, and sufficient conductivity cannot be exhibited. On the other hand, 9
If it exceeds μm, the smoothness of the electrodeposition coated surface is deteriorated and the image clarity is deteriorated.

As the conductive material, iron phosphide, graphite, antimony-doped tin oxide, antimony-doped indium oxide, antimony-doped tin oxide-coated titanium oxide, carbon black, titanium black, metal powder and the like can be used. it can. In addition, the above conductive material
It is also possible to use a mixture of two or more species. Iron phosphide is most preferable from the viewpoint of the influence on the thread rust resistance and the conductivity.

In the present invention, the above-mentioned lubricant, rust preventive additive and conductive substance are the main additive components in the block urethane modified epoxy resin. In addition to this, a silane coupling agent and a coloring agent are added. It is also possible to mix one or more kinds of pigments (for example, condensed polycyclic organic pigments, phthalocyanine organic pigments, etc.), coloring dyes (for example, azo dyes, azo metal complex salt dyes, etc.), and surfactants. is there.

The organic film of the present invention described above has a thickness of 0.05 to 2 μm. If the film thickness is less than 0.05 μm, sufficient thread rust resistance, lubricity, and scratch resistance cannot be expected, while if it exceeds 2 μm, weldability and sharpness deteriorate. Further, in order to satisfy higher thread rust resistance, lubricity, scratch resistance, weldability, and sharpness,
The range of 1.5 μm is preferable.

Application of the coating composition to an aluminum plate for obtaining the organic film of the present invention is usually carried out by a roll coater method, but after application by a dipping method or a spray method, the coating amount is applied by an air knife method or a roll drawing method. It is also possible to adjust. The heat treatment after applying the coating composition can be performed in a hot air oven, a high frequency induction heating oven, an infrared oven or the like. The heat treatment is performed at an ultimate plate temperature of 50 to 300 ° C, preferably 60 to 250 ° C. Furthermore, when the present invention is applied to an aluminum plate having a BH property, heat treatment at 170 ° C. or lower is preferable.

The aluminum plate of the present invention usually has a chromate film + organic film on both sides of the aluminum plate, but in some cases, the chromate film + organic film is applied to only one surface, and the other one surface is, for example, an oxide film. As it is on the aluminum plate surface As it is, on the aluminum plate surface with the oxide film removed, it is possible to adopt any mode such as only the chromate film.

[0050]

EXAMPLES Examples of the present invention will be shown below together with comparative examples. 50g of aluminum alloy plate before chromate treatment
It was immersed in an aqueous sodium hydroxide solution of 1 / l, 50 ° C. for 2 minutes, and the oxide film was removed by washing with water, neutralization with nitric acid, washing with water and drying. After removing the oxide film, chromate treatment was performed, and then the coating composition was applied by a roll coater and baked. Also, for some aluminum alloy sheets, spray degreasing with 20 g / l, 60 ° C. sodium orthosilicate aqueous solution for 20 seconds, washing with water, drying and chromate treatment, then coating composition with a roll coater and baking. It was

With respect to the composite-coated aluminum alloy plate thus obtained, thread rust resistance, image clarity, paint adhesion,
Each evaluation test of scratch resistance was performed. The processing conditions of this example are as follows. Aluminum alloy plate JIS 5052 equivalent thickness 1.0 mm, surface roughness (Ra) 1.
A 0 μm aluminum alloy plate was used as a processed original plate.

Chromate treatment a. Coating Chromate Treatment A chromate treatment liquid having the following liquid composition was applied by a roll coater and dried without washing with water. The amount of the chromate film deposited was adjusted by changing the peripheral speed ratio of the pickup roll of the roll coater and the applicator roll. Chromic anhydride: 20 g / l Phosphate ion: 4 g / l Zirconium fluoride ion: 1 g / l Zinc ion: 1 g / l Hexavalent chromium / Trivalent chromium: 3/3 (weight ratio) Chromic anhydride / zirconium fluoride Ion: 20/1
(Weight ratio) b. Electrolytic chromate treatment Chromic anhydride 30 g / l, sulfuric acid 0.2 g / l, bath temperature 40 ° C
An aluminum alloy plate was subjected to cathodic electrolysis treatment at a current density of 10 A / dm ² using the treatment liquid of Example ¹ , washed with water and dried.
The amount of the chromate film deposited was adjusted by controlling the amount of electricity applied during the cathodic electrolysis treatment.

Organic Resins Table 1 shows the block urethane-modified epoxy resins used in this example and the resins used as comparative examples. In addition, the block urethane-modified epoxy resin No. 1 to N
o. 14 was produced by the method shown below.

A. Modified epoxy resin (A) In a reactor equipped with a condenser, a stirrer and a thermometer, 500 parts of bisphenol A type epoxy resin having an epoxy equivalent of 1500, 385 parts of xylene and 3 of cyclohexanone.
85 parts was added, and the mixture was heated and dissolved under stirring. Furthermore, 20 parts of isopropanol amine was added and reacted at 100 ° C. for 5 hours, and further, NCO% (isocyanate%) was 13%.
65 parts of 2,4-tolylene diisocyanate and octyl alcohol adduct monoisocyanate are added,
The reaction was carried out at 0 ° C. for 5 hours to obtain a modified epoxy resin A having a resin content of 40%.

B. Block urethane (B) In a reactor equipped with a condenser, a stirrer, and a thermometer, 440 parts of polyethylene glycol having a molecular weight of 1000 and 125 parts of xylene are put, and the mixture is heated at 60 ° C. under stirring for 2,6-
153 parts of tolylene diisocyanate are added. The NCO% of this intermediate was 4.8%. Further, 106 parts of ε-caprolactam was added to continue the reaction, and after confirming that NCO% was 0, 175 parts of butanol was added to obtain a block urethane B1 having a resin content of 70%. An intermediate having an NCO% of 2.3% was obtained from 500 parts of polyethylene glycol having a molecular weight of 2000, 300 parts of xylene and 87 parts of 2,6-tolylene diisocyanate under the same apparatus and reaction conditions. Furthermore, 57 parts of ε-caprolactam was added, the reaction was continued, and after confirming that NCO% was 0, 129 parts of butanol was added to obtain a blocked urethane B2 having a resin content of 60%. Under the same equipment and reaction conditions, 500 parts of polypropylene glycol having a molecular weight of 4000, 300 parts of xylene and 42 of hexamethylene diisocyanate.
An intermediate having an NCO% of 1.2% was obtained from the parts. Furthermore, 23 parts of methyl ethyl ketoxime was added to continue the reaction, and N
After confirming that CO% was 0, 77 parts of butanol was added to obtain a block urethane B3 having a resin content of 60%.

Lubricants Table 2 shows the lubricants used in this example.

Antirust Additives Table 3 shows the antirust additives used in this example.

Conductive Substances Table 4 shows the conductive substances used in this example.

Tables 5 to 14 show the constitutions of the composite coated aluminum alloy sheets prepared in this example and the evaluation results of their corrosion resistance (thread rust resistance), image clarity, paint adhesion, weldability and scratch resistance. Shown in. The evaluation method of each characteristic is as follows.

A) Corrosion resistance (thread rust resistance) The test material was treated with zinc phosphate PBL-3020 manufactured by Nippon Parkerizing Co., Ltd., and then U-6 manufactured by Nippon Paint Co., Ltd.
After electrodeposition coating (25μ) with 00, Kansai Paint Co., Ltd.
An intermediate coating (30 μ) was made with KPX-36 manufactured by KPX-36, and a top coat was applied (35 μ) with Lugerbake B-531 manufactured by Kansai Paint Co., Ltd. Cross-cuts were put on these test pieces with a cutter knife, and a salt rust resistance test of [24 hours → wetting test (40 ° C., 85% relative humidity) ・ 720 hours] was performed to corrode from the black cut portion. The corrosion resistance (yarn rust resistance) was evaluated by the swollen width. The evaluation criteria are as follows. ◎: Less than 1 mm ○: 1 mm or more and less than 2 mm △: 2 mm or more and less than 4 mm ×: 4 mm or more

B) Image clarity: The test material was subjected to the same electrodeposition coating, intermediate coating and top coating as in the above a), and the image clarity measuring device (IC) manufactured by Suga Test Instruments Co., Ltd.
M-2DP) and the image clarity C when a slit of 0.5 mm was used. The evaluation criteria are as follows. ◎: 80 or more ○: less than 80, 75 or more △: less than 75, 70 or more ×: less than 70

C) Paint Adhesion The test piece was subjected to the same electrodeposition coating, intermediate coating and top coating as in the above a), and these test pieces were immersed in ion exchanged water at 40 ° C. for 240 hours. Then take out the test piece,
After leaving it at room temperature for 24 hours, 100 cross-cuts were cut on the coating film at intervals of 2 mm, a cellophane tape was adhered and peeled off, and the residual rate of the coating film was evaluated. The evaluation criteria are as follows. ◎: No peeling ○: Less than 3% △: 3% or more and less than 10% ×: 10% or more

D) Weldability DR type electrode (tip diameter 6 mm), applied pressure: 270 kgf,
Energization time: 5 cycles / 50 Hz, welding current: 25 kA
The continuous dotability test was conducted with JIS Z 31
The tensile shear load is measured based on 36 and JIS Z 3140
The number of RBIs was evaluated based on. The evaluation criteria are as follows. ◎: 1200 points or more ○: 800 points or more and less than 1200 points Δ: 500 points or more and less than 800 points ×: less than 500 points

E) Scratch resistance Using a weighted scratch strength tester, the test material was subjected to a scratch test with a sapphire needle (0.05 mmφ) under a constant load and evaluated by the load at which scratches began to be observed. .. The evaluation criteria are as follows. A: 50 g or more O: 40 g or more and less than 50 g B: 30 g or more, less than 40 g X: less than 30 g

F) Press formability Punch: 50 mmφ · R8, Die: 53 mmφ · R
5, blank diameter: 110 mmφ, BHF: 3.6 ton
The press formability was evaluated by carrying out deep drawing at, and measuring the forming height until cracking. The evaluation criteria are as follows. A: 15 mm or more O: 14 mm or more and less than 15 mm B: 13 mm or more and less than 14 mm X: less than 13 mm

In Table 5 to Table 14, No. 1-No. In No. 8, the effect of chromate treatment was investigated. No. 1 and No. 9-No. 29, No. 77, No. At 78,
The influence of the resin blended in the organic film was investigated. N
o. 1 and No. 30-No. In No. 42, the effect of the lubricant compounded in the organic film was examined. No. 1 and No. 43-No. 60, No. In 79, the effect of the rust preventive additive incorporated in the organic film was examined. No.
1 and No. 61-No. 69, No. In 79, the effect of the conductive substance contained in the organic film was examined.
No. 70-No. In No. 75, the influence of the film thickness of the organic film was examined. No. In 80, the effect of the oxide film on the original plate was examined.

[0067]

[Table 1]

[0068]

[Table 2]

[0069]

[Table 3]

[0070]

[Table 4]

[0071]

[Table 5]

[0072]

[Table 6]

[0073]

[Table 7]

[0074]

[Table 8]

[0075]

[Table 9]

[0076]

[Table 10]

[0077]

[Table 11]

[0078]

[Table 12]

[0079]

[Table 13]

[0080]

[Table 14]

[0081]

[Table 15]

[0082]

[Table 16]

* 1 Emission: Example of the present invention Ratio: Comparative example * 2 Chromate adhesion amount in terms of metallic chromium * 3 See Table 1 * 4 Nonvolatile content by weight * 5 See Table 2 * 6 See Table 3 * 7 Nonvolatile content Weight ratio * 8 See Table 4 * 9 Aluminum alloy plate with oxide film removed * 10 Aluminum alloy plate is spray degreased with sodium orthosilicate, washed with water, dried and chromated,
Then, the coating composition is applied by a roll coater and baked.

[0084]

As described above, according to the present invention, excellent press formability is ensured while ensuring good image clarity,
Moreover, since it has excellent thread rust resistance, scratch resistance, paint adhesion, and spot welding is possible, it is extremely useful as an aluminum plate or aluminum alloy plate for automobiles and home appliances. Further, since the composite-coated aluminum plate or aluminum alloy plate of the present invention suppresses the elution of aluminum into the treatment liquid during the phosphating treatment, it is treated at the same time as the steel sheet in the existing automobile phosphating process. However, the eluted aluminum does not hinder the formation of the phosphate coating on the steel sheet. Further, the aluminum plate and aluminum alloy plate of the present invention can obtain excellent thread rust resistance and paint adhesion even if the phosphate treatment step is omitted.

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[Procedure amendment]

[Submission date] December 18, 1991

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Title of invention

[Correction method] Change

[Correction content]

[Title of Invention] press formability, scratch resistance, resistance to yarn rust resistance and sharpness excellent composite coated aluminum plate or aluminum alloy plate

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Internal reference number FI Technical indication C23C 22/00 Z C25D 11/38 C (72) Inventor Masaaki Yamashita 1-chome, Marunouchi, Chiyoda-ku, Tokyo No. 2 Nihon Steel Pipe Co., Ltd. (72) Inventor Toyofumi Watanabe 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Steel Pipe Co., Ltd. (72) Inventor Yoshio Kikuta 1900, Togo, Mobara-shi, Chiba Mitsui Toatsu (72) Inventor Kimio Kobori 1900, Togo, Mobara-shi, Chiba Prefecture Mitsui Toatsu Chemical Co., Ltd. (72) Inventor, Takashi Yokoyama 1900, Togo, Mobara-shi, Chiba Prefecture Mitsui Toatsu Chemical Co., Ltd.

Claims (13)

[Claims] 1. A chromate layer as a first layer on the surface of an aluminum plate or an aluminum alloy plate having a chromate layer of 1 to 150 mg / m ^{2 in} terms of metallic chromium, and a second layer above the chromate layer in the following proportion as a block urethane-modified epoxy resin. A composite-coated aluminum plate or aluminum alloy plate having an excellent press formability, scratch resistance, yarn rust resistance, and sharpness, which has an organic film having a film thickness of 0.05 to 2 μm containing a lubricant and a lubricant. Block urethane-modified epoxy resin: 30-80 wt% Lubricant: 5-60 wt% However, weight% of non-volatile content 2. A chromate layer as a first layer having a chromate layer of 1 to 150 mg / m ^{2 in} terms of metallic chromium on the surface of an aluminum plate or an aluminum alloy plate, and a second layer above it as a second layer having a block urethane-modified epoxy resin in the following ratio: A composite-coated aluminum plate having an excellent press-formability, scratch resistance, yarn rust resistance and sharpness, which has an organic film having a film thickness of 0.05 to 2 μm containing a lubricant, a lubricant and an anticorrosive additive, or Aluminum alloy plate. Block urethane modified epoxy resin: 30 to 80 wt% Lubricant: 5 to 60 wt% Rust preventive additive: 3 to 50 wt% However, weight% of non-volatile content 3. A block urethane-modified epoxy resin having a chromate layer as a first layer of 1 to 150 mg / m ^{2 in} terms of metallic chromium on the surface of an aluminum plate or an aluminum alloy plate, and a second layer above the chromate layer in the following ratio. A composite-coated aluminum plate or aluminum having an excellent press formability, scratch resistance, yarn rust resistance and image clarity, which has an organic film having a film thickness of 0.05 to 2 μm containing a lubricant, a conductive material and a conductive substance. Alloy plate. Block urethane modified epoxy resin: 30 to 80 wt% Lubricant: 5 to 60 wt% Conductive substance: 2 to 40 wt% However, weight% of non-volatile content 4. A block urethane modified epoxy resin having a chromate layer as a first layer of 1 to 150 mg / m ^{2 in} terms of metallic chromium on the surface of an aluminum plate or an aluminum alloy plate, and a second layer above the chromate layer in the following ratio. And a lubricant, a rust preventive additive, and a conductive substance having a film thickness of 0.05 to
A composite-coated aluminum plate or aluminum alloy plate having an organic coating of 2 μm, which is excellent in press moldability, scratch resistance, yarn rust resistance and sharpness. Block urethane modified epoxy resin: 30 to 80 wt% Lubricant: 5 to 60 wt% Rust preventive additive: 3 to 50 wt% Conductive substance: 2 to 40 wt% However, weight% of non-volatile content 5. The lubricant constituting the organic coating comprises one or more lubricants selected from the group consisting of fluororesin, graphite and boron nitride, claim 1, claim 2, claim 3 or claim 4. 7. A composite coated aluminum plate or aluminum alloy plate excellent in press formability, scratch resistance, yarn rust resistance and image clarity as described in 1. 6. The rust preventive additive constituting the organic coating comprises one or more rust preventive additives selected from the group consisting of silica and chromate. A composite coated aluminum plate or aluminum alloy plate with excellent press formability, scratch resistance, yarn rust resistance and image clarity. 7. The press-moldability, scratch resistance, yarn rust resistance, and sharpness of image as claimed in claim 6, wherein the rust-preventive additive constituting the organic film comprises silica and chromate in the following proportions. Composite coated aluminum plate or aluminum alloy plate. Silica / chromate = 90/10 to 10/90 (weight ratio) 8. A block urethane (B) comprising a block urethane-modified epoxy resin constituting an organic film, which comprises polyethylene glycol, polyisocyanate and a blocking agent, in contrast to a modified epoxy resin (A) obtained by modifying an epoxy resin with a polyfunctional amine. A / B = 95/5 to 50/5
The press moldability according to claim 1, claim 2, claim 3, claim 4, claim 5, claim 6, or claim 7, which is a block urethane-modified epoxy resin mixed in a ratio of 0 (weight ratio). , Composite coated aluminum plate or aluminum alloy plate with excellent scratch resistance, yarn rust resistance and sharpness. 9. A chromate layer as a first layer having a chromate layer of 1 to 150 mg / m ^{2 on the} surface of an aluminum plate or an aluminum alloy plate in terms of metallic chromium, and a second layer as a second layer above the block urethane-modified epoxy resin: 30 to 80 wt% Lubricant: 5 to 60 wt% However, an organic film having a film thickness of 0.05 to 2 μm containing a block urethane-modified epoxy resin in a proportion of non-volatile content by weight and a lubricant, and the block urethane-modified epoxy A resin is a modified epoxy resin (A) obtained by modifying an epoxy resin with a polyfunctional amine, and a block urethane (B) composed of polyethylene glycol, polyisocyanate and a blocking agent is A /
B is a block urethane-modified epoxy resin mixed in a ratio (weight ratio) of 95/5 to 50/50, and the lubricant is one or more lubricants selected from the group consisting of fluororesin, graphite and boron nitride. A composite-coated aluminum plate or aluminum alloy plate excellent in press formability, scratch resistance, yarn rust resistance, and image clarity having an organic film. 10. A chromate layer as a first layer having a chromate layer of 1 to 150 mg / m ^{2 on the} surface of an aluminum plate or an aluminum alloy plate, and a second layer as a second layer above the block urethane-modified epoxy resin: 30 to 80 wt% Lubricant: 5 to 60 wt% Anticorrosion additive: 3 to 50 wt% However, a film thickness containing a block urethane modified epoxy resin in a proportion of non-volatile content by weight, a lubricant and an anticorrosion additive is 0.05 to A block urethane (B) having a 2 μm organic film, in which the block urethane-modified epoxy resin is composed of a polyethylene glycol, a polyisocyanate, and a blocking agent, in contrast to a modified epoxy resin (A) obtained by modifying the epoxy resin with a polyfunctional amine. Block urethane modified epoxy resin in which A / B was mixed at a ratio of 95/5 to 50/50 (weight ratio) Fat, the lubricant comprises one or more lubricants selected from the group consisting of fluororesin, graphite and boron nitride, and the rust-preventive additive is silica / chromate = 90/10 to 10/90. (Comparison by weight) A composite-coated aluminum plate or aluminum alloy plate having an organic film made of silica and chromate, which is excellent in press formability, scratch resistance, yarn rust resistance and sharpness. 11. A chromate layer as a first layer on the surface of an aluminum plate or an aluminum alloy plate having a chromate layer of 1 to 150 mg / m ^{2 in} terms of metallic chromium, and a second layer as a second layer above the block urethane-modified epoxy resin: 30 to 80 wt% Lubricant: 5 to 60 wt% Conductive substance: 2 to 40 wt% However, a film thickness of 0.05 to 2 μm containing a block urethane modified epoxy resin in a proportion of non-volatile content by weight, a lubricant and a conductive substance An organic film, wherein the block urethane-modified epoxy resin is a modified epoxy resin (A) obtained by modifying an epoxy resin with a polyfunctional amine, and a block urethane (B) composed of polyethylene glycol, polyisocyanate and a blocking agent / B = block urethane-modified epoxy resin mixed at a ratio (weight ratio) of 95/5 to 50/50 Press moldability, scratch resistance, yarn rust resistance and freshness, which is an oil and has an organic film made of one or more lubricants selected from the group consisting of fluororesin, graphite and boron nitride. Composite coated aluminum plate or aluminum alloy plate with excellent image clarity. 12. A surface of an aluminum plate or an aluminum alloy plate has a chromate layer as a first layer of 1 to 150 mg / m ^{2 in} terms of metallic chromium, and a second layer as a second layer above the block urethane-modified epoxy resin: 30 to 80 wt% Lubricant: 5-60 wt% Rust preventive additive: 3-50 wt% Conductive material: 2-40 wt% However, non-volatile content by weight% Block urethane modified epoxy resin, lubricant and rust preventive additive Film thickness including conductive material 0.05-2 μm
Which is an organic film, and the block urethane-modified epoxy resin comprises a modified urethane resin (A) obtained by modifying an epoxy resin with a polyfunctional amine, and a blocked urethane (B) comprising polyethylene glycol, polyisocyanate and a blocking agent. A / B = block urethane-modified epoxy resin mixed in a ratio (weight ratio) of 95/5 to 50/50, wherein the lubricant is one or more kinds of lubrication selected from the group consisting of fluororesin, graphite and boron nitride. And an anticorrosive additive having an organic coating film of silica and chromate in the proportion of silica / chromate = 90/10 to 10/90 (weight ratio). Composite coated aluminum plate or aluminum alloy plate with excellent scratch resistance, yarn rust resistance and sharpness. 13. The oxide film thickness of the aluminum plate or aluminum alloy plate surface is 100 Å or less, claim 1, claim 3, claim 4, claim 5, claim 6, claim 7, claim 7. Claim 8, Claim 9, Claim 10, and Claim 11
Alternatively, the press formability, scratch resistance according to claim 12,
Composite coated aluminum plate or aluminum alloy plate with excellent rust resistance and sharpness.