JP2787124B2 - Composite coated aluminum plate or aluminum alloy plate excellent in press formability, scratch resistance, yarn rust resistance and sharpness - Google Patents

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 excellent in press formability, scratch resistance, thread rust resistance and sharpness used for automobile bodies and home electric appliances. .

[0002]

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

Conventionally, as a method of improving the press formability and the rust resistance of an aluminum alloy sheet, a method of forming a chromate layer on the surface of the aluminum alloy sheet and forming an organic resin film on the chromate layer (Japanese Patent Laid-Open Publication No. Hei. 140480
No.) has been proposed. As a method for improving the formability of a steel sheet, which is not an aluminum alloy sheet, a method of forming a chromate layer on the surface of the steel sheet and forming an organic resin film containing a fluororesin and silica on the chromate layer (Japanese Patent Application Laid-Open 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 thereon. No.) has been proposed.

[0004]

However, in the method disclosed in Japanese Patent Application Laid-Open No. HEI 3-140480, although it is possible to improve the rust resistance, press molding is not performed because the organic film contains no lubricant. However, there is a problem that the sharpness and the weldability are not sufficient. 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-based resin is used as a binder for an organic film. Due to the use, the adhesion to the cationic electrodeposition coating applied to the vehicle body is insufficient, and the sharpness and weldability are also insufficient. Further, according to the method disclosed in JP-A-63-83172, although the organic film contains a conductive substance, good weldability can be obtained, but an epoxy resin having relatively high hydrophobicity is used as a binder for the organic film. Therefore, there is a problem that the sharpness is insufficient and the press formability is not sufficient because a wax-based lubricant is used.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and when applied to an automobile body, there is little damage to a plate during handling, and excellent formability in a pressing process. It is another object of the present invention to provide a composite coated aluminum plate or aluminum alloy plate having excellent outer surface rust resistance and high sharpness on the outer surface side of a vehicle body outer plate.

[0006]

Means for Solving the Problems In order to achieve such an object, the present inventors have studied the coating constitution to be applied to an aluminum plate and an aluminum alloy plate, and have obtained the following knowledge. By adding a lubricant such as fluororesin, graphite, boron nitride, etc. to the organic film and imparting lubricity to the surface, press formability is improved. Chromate film as a base film suppresses thread rust, and the upper layer The effect becomes more remarkable by adding rust preventive additives such as silica and chromate to the organic film. The weldability is deteriorated by forming the organic film on the surface of 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 the cationic electrodeposition paint, the epoxy resin is modified with polyfunctional amine and monoisocyanate. By introducing polyethylene glycol into the block urethane as a curing agent, Appropriate hydrophilicity is imparted, and by promoting the deposition of a uniform electrodeposition coating over the entire surface, a smooth electrodeposition coating is obtained and excellent sharpness is ensured. This is characterized by having the following configuration.

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

[3] On the surface of an aluminum plate or an aluminum alloy plate, a chromate layer is provided as a first layer in an amount of 1 to 150 mg / m ^{2 in} terms of metal chromium, and a second layer is formed thereon as a second layer. A composite coated aluminum plate having an organic coating having a thickness of 0.05 to 2 μm containing a resin, a lubricant and a conductive substance and having excellent press moldability, scratch resistance, thread rust resistance and sharpness; 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 components

[4] On the surface of an aluminum plate or an aluminum alloy plate, a chromate layer having a thickness of 1 to 150 mg / m ^{2 in} terms of metal chromium is provided as a first layer, and a block urethane-modified epoxy having the following ratio is provided as a second layer above the chromate layer. 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 and 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, the weight percentage of non-volatile components

[5] In the aluminum plate or aluminum alloy plate according to the above [1], [2], [3] or [4], the lubricant constituting the organic film is a fluororesin, graphite and boron nitride. A composite coated aluminum plate or aluminum alloy plate having excellent press moldability, scratch resistance, thread rust resistance and sharpness, comprising one or more lubricants selected from the group consisting of:

[6] The above [2], [4] or [5]
In the aluminum plate or the aluminum alloy plate according to the above, the rust-preventive additive constituting the organic film is formed of at least one rust-preventive additive selected from the group consisting of silica and chromate. Composite coated aluminum plate or aluminum alloy plate with excellent resistance, yarn 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 silica and chromate in the following proportions, and has press formability and scratch resistance. A composite coated aluminum plate or aluminum alloy plate excellent in thread rust resistance and sharpness. Silica / chromate = 90/10 to 10/90 (weight ratio)

[8] The above [1], [2], [3],
[4] The modified epoxy resin according to [5], [6] or [7], wherein the block urethane-modified epoxy resin constituting the organic film is an epoxy resin modified with a polyfunctional amine. Resin (A)
To block urethane (B) composed of polyethylene glycol, polyisocyanate and blocking agent
/ B = 95/5 to 50/50 (weight ratio), a composite coated aluminum plate which is a block urethane-modified epoxy resin and excellent in 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 of 1 to 150 mg / m ^{2 in} terms of metal chromium is provided as a first layer, and a block urethane-modified epoxy resin is 30 to 80 wt% as a second layer thereon. Lubricant: 5 to 60 wt%, provided that the block urethane-modified epoxy resin is a 0.05 to 2 μm-thick organic film 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 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 with A /
B = a block urethane-modified epoxy resin mixed at a ratio of 95/5 to 50/50 (weight ratio), wherein the lubricant is at least one lubricant selected from the group consisting of fluororesin, graphite and boron nitride. A composite coated aluminum plate or aluminum alloy plate having an organic coating and excellent in press formability, scratch resistance, yarn rust resistance and sharpness.

[10] On the surface of the aluminum plate or aluminum alloy plate, a chromate layer having a thickness of 1 to 150 mg / m ^{2 in} terms of metal chromium is provided as a first layer, and a second layer is provided on the 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% However, the proportion of non-volatile content by weight of block urethane-modified epoxy resin, lubricant and rust prevention An organic film having a thickness of 0.05 to 2 μm containing 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; A block urethane-modified epoxy resin obtained by mixing block urethane (B) comprising an isocyanate and a blocking agent in a ratio (weight ratio) of A / B = 95/5 to 50/50, wherein the lubricant is a fluororesin, graphite, or a nitride. A rust-preventive additive comprising one or more lubricants selected from the group consisting of boron; Acid salt = 90/10 to 10/90 (weight ratio) Excellent in press moldability, scratch resistance, rust resistance and sharpness, having an organic film composed of silica and chromate in a ratio of 90/10 to 10/90 (weight ratio). Composite coated aluminum plate or aluminum alloy plate.

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

[12] On the surface of the aluminum plate or aluminum alloy plate, a chromate layer as a first layer is provided at 1 to 150 mg / m ^{2 in} terms of metal chromium, and a second layer is
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 substance: 2 to 40 wt% However, the ratio of block urethane modified by weight of non-volatile content is A film thickness of 0.05 to 2 μm including an epoxy resin, a lubricant, a rust preventive additive, and a conductive substance.
And the block urethane-modified epoxy resin is a modified epoxy resin (A) obtained by modifying an epoxy resin with a polyfunctional amine with a block urethane (B) composed of polyethylene glycol, polyisocyanate and a blocking agent. A block urethane-modified epoxy resin mixed at a ratio of A / B = 95/5 to 50/50 (weight ratio), wherein the lubricant is at least one type of lubricant selected from the group consisting of fluororesins, graphite and boron nitride. Moldability, wherein the rust-preventive additive has an organic film composed of silica and chromate in a ratio of silica / chromate = 90/10 to 10/90 (weight ratio). A composite coated aluminum plate or aluminum alloy plate with excellent scratch resistance, thread rust resistance and sharpness.

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

[9],
[10] The aluminum plate or aluminum alloy plate according to [11] or [12], wherein the aluminum plate or the aluminum alloy plate has an oxide film thickness of 100 ° or less on the press formability, scratch resistance, and thread rust resistance. Composite coated aluminum plate or aluminum alloy plate with excellent properties and sharpness.

[0020]

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

An oxide film having a thickness of about several hundreds of millimeters is formed on the surface of the aluminum plate after rolling and annealing, and this oxide film impairs the electrical conductivity when welding the aluminum plate. It is preferable to dissolve / remove with an alkaline aqueous solution or the like, since the property is significantly deteriorated. Oxide film thickness is 10
If it is 0 ° or less, good weldability can be ensured, and in order to obtain particularly high weldability, the oxide film thickness is preferably 80 ° 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 a trivalent chromium which is a reduction product of chromate ions. The chromium hydrated oxide film covers the surface to reduce the anode area, and furthermore, 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 adhesion amount of the chromate film is 1 to 150 mg / m ^{2 in} terms of chromium metal. 1m adhesion amount
If it is less than g / m ² , sufficient yarn rust resistance cannot be expected, while if it exceeds 150 mg / m ² , the weldability will deteriorate. Further, in order to obtain higher thread rust resistance and weldability, the content is preferably in the range of 5 to 100 mg / m ² .

As the chromate treatment for forming the chromate film, any of a reaction type, an electrolytic type and a coating type can be applied. From the viewpoint of yarn rust resistance, a coating type containing a large amount of chromate ions of hexavalent chromium in the chromate film is preferable. The coating type chromate treatment is mainly composed of a partially reduced aqueous solution of chromic acid, and a treatment liquid containing one or more of the following components, if necessary, is applied to an aluminum plate and washed with water. Dry without drying. 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 their salts phosphorus Phosphoric acids such as acid and polyphosphoric acid Zirconium fluoride, silicide fluoride, fluoride such as titanium fluoride Metal ion such as zinc ion Conductive fine powder such as iron phosphide, antimony-doped tin oxide The treatment liquid is applied by a roll coater method, but it is also possible to adjust the application amount by an air knife method or a roll drawing method after applying by a dipping method or a spray method.

The organic film formed as a second layer on the chromate layer contains a predetermined amount of a 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 to the aluminum alloy, the anticorrosion effect is maintained, and the lubricating agent provides good lubrication characteristics of the aluminum plate during press working.
In addition, if necessary, the addition of a rust-preventive additive such as silica or chromate to the organic film further improves the filiform rust resistance. And good weldability is obtained.

Examples of the epoxy resin constituting the urethane-modified epoxy resin include epoxy resins obtained by glycidyl etherification of bisphenol A, bisphenol F, and novolak, and epoxy resins obtained by adding propylene oxide or ethylene oxide to bisphenol A and glycidyl etherification. Can be used. In addition, aliphatic epoxy resins, alicyclic epoxy resins, and polyether-based epoxy resins can also be used, and two or more 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 an epoxy resin with a polyfunctional amine in terms of corrosion resistance and adhesion to a cationic electrodeposition coating. A modified epoxy resin is obtained by reacting a glycidyl group of the epoxy resin with a polyfunctional amine. Examples of the polyfunctional amine include primary alkanolamines such as ethanolamine, propanolamine, isopropanolamine and butanolamine, primary alkylamines such as propylamine, butylamine, octylamine and decylamine, ethylenediamine, diethylenetriamine, tetraethylenepentamine and xylene. Diamines, aminoethylpiperazines, norbornanediaminomethyls, and the like having two or more active hydrogens in one molecule, and two or more of these amines can be used in combination. As the polyfunctional amine, alkanolamine is most preferred from the viewpoints of yarn rust resistance and paint adhesion.

The active hydrogen of the amine is excessive relative to the glycidyl group, and the active hydrogen of the amine is present in the modified epoxy resin. The reaction of the active hydrogen with the monoisocyanate does not interfere at all, and has the effect of further improving the corrosion resistance. As an example of the synthesis of the modified epoxy resin, the active hydrogen of the polyfunctional amine is mixed with the glycidyl group of the epoxy resin in an amount equivalent to 1.1 to 1.8 times, and the mixture is mixed at 70 to 150 ° C. for 4 to 10 hours After the reaction, monoisocyanate is further added in an amount equivalent to 0.7 to 2.0 times the active hydrogen of the remaining amine, and the reaction is continued at 30 to 100 ° C.

The block urethane of the present invention is a compound obtained by protecting a strongly active isocyanate group of an isocyanate compound with an appropriate compound to make it inactive. When heated, the blocking agent is dissociated and the activity of the isocyanate group is easily regenerated. Things. That is, it has a role as a curing agent for the modified epoxy resin. By introducing polyethylene glycol into block urethane, the present inventors impart appropriate hydrophilicity to the organic film, and as a result, water uniformly penetrates the entire organic film at the time of cationic electrodeposition coating. It has been found that deposition of a smooth electrodeposited film occurs and a smooth electrodeposited film is obtained. Therefore, the block urethane is most preferably one in which polyethylene glycol is introduced, that is, one composed of polyethylene glycol, polyisocyanate and a blocking agent.

Polyethylene glycol has the general formula

Embedded image And the molecular weight is 400 or more. Further, the more preferable molecular weight is 1500 or more. When polyethylene glycol is used, appropriate hydrophilicity is imparted to the organic film, resulting in improved compatibility with the cationic electrodeposition paint, and a smooth electrodeposition surface obtained, and excellent sharpness after the middle and top coatings. Property is obtained.

Examples of the polyisocyanate include aliphatic isocyanates such as hexamethylene diisocyanate and trimethylhexamethylene diisocyanate, xylylene diisocyanate, 2,4-tolylene diisocyanate,
Aromatic isocyanates such as 2,6-tolylene diisocyanate, alicyclic isocyanates such as isophorone diisocyanate and norbornane diisocyanate methyl, and mixtures and polynuclears thereof can be used. Phenolic compounds such as phenol, ε
Lactam compounds such as caprolactam, oxime compounds such as methyl ethyl ketoxime, and imine compounds such as ethyleneimine;
It is also possible to use mixtures of more than one species.

Block urethane is used to synthesize a prepolymer by mixing and reacting the two so that the isocyanate groups of the polyisocyanate are in excess of the hydroxyl groups of the polyol, and furthermore, the remaining isocyanate groups of the prepolymer are protected with a blocking agent. It is obtained by doing. In addition, these reaction temperatures are 30-100 degreeC.

The block urethane-modified epoxy resin of the present invention can be obtained by mixing the above-mentioned modified epoxy resin with 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 a corrosion resistance,
It is most preferable in terms of coating adhesion and sharpness, and the mixing ratio in this case is preferably in the range of A / B = 95/5 to 50/50. The ratio of the modified epoxy resin (A) is 95/5
If it exceeds 300, there is a problem that the sharpness after the middle / overcoating is deteriorated. The ratio of the modified epoxy resin (A) is 50/50.
If the amount is less than the above, the rust resistance deteriorates. A / B = 90/10 to 60/4 in order to obtain even higher sharpness and rust resistance.
A range of 0 is preferred.

The blending amount of the block urethane-modified epoxy resin in the organic film is 30 to 80% by weight. 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 paint adhesion and the scratch resistance are poor. On the other hand, when the content exceeds 80% by weight, the hydroxyl groups in the block urethane-modified epoxy resin skeleton adhere to the press die, and the moldability deteriorates. Further, in order to satisfy even higher paint adhesion, scratch resistance and press moldability, 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 suppress the adhesion between the press die and the aluminum plate and to improve the press formability. The amount of lubricant added to the organic film is 5-60w
t%. If the amount of the lubricant added is less than 5 wt%, sufficient press formability cannot be expected, while 60 wt%
%, The adhesion to the cationic electrodeposition coating material deteriorates.
In order to satisfy even higher press moldability and paint adhesion, the content is preferably in the range of 10 to 50 wt%.

When the lubricant is in the form of particles, the average particle diameter is preferably in the range of 0.1 to 9 μm. The lubricant added to the organic film is considered to reduce the friction coefficient of the surface by appropriately exposing it to the surface of the organic film and to impart lubricity to the plate. It cannot be appropriately exposed to the film surface, and the press formability deteriorates. On the other hand, if it exceeds 9 μm, the smoothness of the electrodeposition coated surface is reduced, and the sharpness is deteriorated.

As the lubricant used in the present invention, a fluorine resin (for example, ethylene tetrafluoride resin, ethylene tetrafluoride-hexafluoropropylene copolymer resin, ethylene tetrafluoride-perfluoroalkyl vinyl ether copolymer resin, Fine powder such as ethylene tetrafluoride-ethylene copolymer resin, ethylene trifluoride chloride resin, vinylidene fluoride resin), graphite, boron nitride, polyethylene resin, molybdenum disulfide, oily lubricant, carbon fluoride, extreme pressure agent, etc. , Liquids and colloids can be used. From the viewpoint of press moldability, fluororesins, graphite and boron nitride are excellent, and among these fluororesins, ethylene tetrafluoride resin is most preferred.

Next, in the present invention, for the purpose of improving the rust resistance, a rust preventive additive can be added to the organic film in the range of 3 to 50 wt%. If the amount of the rust preventive additive is less than 3 wt%, the effect of improving the rust resistance is insufficient.
%, The coating is peeled off during press molding, deteriorating the moldability. Further, in order to satisfy higher thread rust resistance and moldability, a range of 5 to 40% by weight is preferable.

As the rust preventive additive used in the present invention, fine powders and colloids such as silica, chromate, aluminum trihydrogen diphosphate, aluminum phosphomolybdate and zinc phosphate can be used. Silica and chromate are preferred from the viewpoint of thread rust resistance. It is presumed that silica dissolves in a trace amount in a corrosive environment, and silicate ions function as a film-forming corrosion inhibitor, thereby exhibiting an anticorrosion effect. In addition, chromate is considered to release hexavalent chromate ions by dissolving a trace amount in a corrosive environment, thereby suppressing corrosion of the aluminum plate by the same mechanism as the chromate layer.

By adding silica and chromate in combination, it is possible to obtain even higher thread 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, the most excellent yarn rust resistance is obtained due to the synergistic effect of both anticorrosion effects. Property is obtained. Even if the ratio of silica to chromate exceeds 90/10,
If it is less than 90, the synergistic effect becomes insufficient, and the rust resistance is slightly inferior.

As the silica used in the present invention, 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.), and organosilica sols (e.g., MA-ST, IPA-ST, NBA-ST, IBA- manufactured by Nissan Chemical Industries, Ltd.)
ST, EG-ST, XBA-ST, ETC-ST, DM
AC-ST, etc.), sedimentation wet silica (for example, T-32 (S), K-41, F-80, etc., manufactured by Tokuyama Soda Co., Ltd.), and gel wet silica (for example, Syloid 244 manufactured by Fuji Devison Chemical Co., Ltd.) , Syloid 150, Syloid 72, Syloid 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 hydrophobized 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 electrodeposition paint, which is a water-based paint, is poor, and a smooth electrodeposition coating surface cannot be obtained. Therefore, in order to obtain excellent sharpness, silica whose surface is not hydrophobized is more preferable. In the present invention, as a method of further improving the anticorrosion effect of silica, silica ion-exchanged with a cation having a corrosion inhibitory action (eg, calcium, zinc, cobalt, lead, strontium, lithium, barium, manganese) is used. Can be used. It is considered that these cations exchange ions with protons in a corrosive environment and are released from silica, thereby forming stable corrosion products on the metal surface and suppressing corrosion.

The specific surface area of the silica is from 20 to 100.
A 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 rust resistance is poor, and the smoothness of the electrodeposition coated surface is reduced, and the sharpness is deteriorated. On the other hand, when the specific surface area exceeds 1000 m ² / g, the thixotropic property of the coating composition to which silica is added becomes strong, and the workability when applying with a roll coater or the like is reduced.

The chromate used in the present invention includes barium chromate (BaCrO ₄ ), strontium chromate (SrCrO ₄ ), and calcium chromate (CaCrO ₄ ).
O _4), chromic acid zinc (ZnCrO ₄ · 4Zn (O
H) ₂ ), potassium zinc 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 thread rust resistance, barium chromate and strontium chromate, which can be expected to have a self-healing effect by hexavalent chromate ions over a long period of time, are preferable. Further, from the viewpoint of minimizing the elution of water-soluble chromium from the chromate added to the organic film in the pretreatment step of coating the automobile, barium chromate having low solubility in water is preferable. As the average particle size of the 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-healing effect by hexavalent chromate ions is not maintained, and on the other hand, it exceeds 1 μm. In this case, the smoothness of the electrodeposition coated surface is reduced, and the sharpness is deteriorated.

Next, in the present invention, by adding a conductive substance to the organic film, an appropriate conductivity is imparted to the organic film, and the weldability can be improved. The amount of the conductive substance added to the organic film is 2 to 40% by weight. 2
If the content is less than wt%, the conductivity of the organic film is insufficient, so that the weldability is slightly inferior. On the other hand, if the content exceeds 40 wt%, the conductive substance in the organic film becomes a starting point of the oxygen reduction reaction in a corrosive environment, and the rust resistance is improved. Deteriorates. In order to satisfy even higher weldability and yarn rust resistance, 3 to 30 wt%
Is preferable. As the average particle size of the conductive substance,
The range of 0.01 to 9 μm is preferable. If the thickness is less than 0.01 μm, it is difficult to make a three-dimensional contact between the particles of the conductive substance, so that sufficient conductivity cannot be exhibited. On the other hand, 9
If it exceeds μm, the smoothness of the electrodeposition coated surface is reduced, and the sharpness 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 is
It is also possible to use a mixture of more than one species. Iron phosphide is most preferable from the viewpoint of the effect on the rust resistance and the conductivity.

In the present invention, the above-mentioned lubricant, rust-preventive additive and conductive material are the main additive components in the block urethane-modified epoxy resin. One or more kinds of pigments (eg, condensed polycyclic organic pigments, phthalocyanine-based organic pigments, etc.), coloring dyes (eg, azo-based dyes, azo-based metal complex dyes, etc.), surfactants, and the like can be blended. 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 yarn rust resistance, lubricity and scratch resistance cannot be expected, while if it exceeds 2 μm, weldability and sharpness deteriorate. Further, in order to satisfy even higher thread rust resistance, lubricity, scratch resistance, weldability and sharpness, 0.1 to 0.1%
A range of 1.5 μm is preferred.

The 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. However, after applying by an immersion method or a spray method, the coating amount is applied by an air knife method or a roll drawing method. Adjustments are also possible. The heat treatment after the application of 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 the ultimate plate temperature of 50 to 300 ° C, preferably 60 to 250 ° C. Further, when the present invention is applied to an aluminum plate having BH properties, a heat treatment at 170 ° C. or lower is preferable.

The aluminum plate of the present invention usually has a chromate film and an organic film on both sides of the aluminum plate. In some cases, the chromate film and the organic film are applied to only one surface, and for the other surface, for example, an oxide film is used. Any aspect such as a chromate film alone with the aluminum plate surface from which the oxide film has been removed can be used.

[0050]

EXAMPLES Examples of the present invention will be described below together with comparative examples. 50 g of aluminum alloy plate before chromate treatment
/ L, immersed in an aqueous sodium hydroxide solution at 50 ° C for 2 minutes, washed with water, neutralized with nitric acid, washed with water and dried to remove the oxide film. After removing the oxide film, a chromate treatment was performed, and then the coating composition was applied by a roll coater and baked. Some aluminum alloy plates were spray-degreased with a 20 g / l aqueous solution of sodium orthosilicate at 60 ° C. for 20 seconds, washed with water, dried, subjected to chromate treatment, and then coated with a coating composition using a roll coater and baked. Was.

With respect to the composite coated aluminum alloy sheet thus obtained, the rust resistance, sharpness, paint adhesion,
Each evaluation test of scratch resistance was performed. The processing conditions of this embodiment are as follows. Aluminum alloy plate JIS 5052 equivalent thickness 1.0mm, surface roughness (Ra) 1.
An aluminum alloy plate of 0 μm was used as a processing base plate.

Chromate treatment a. Coating-type chromate treatment A chromate treatment solution having the following liquid composition was applied by a roll coater and dried without washing with water. The adhesion amount of the chromate film was adjusted by changing the peripheral speed ratio between 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
The aluminum alloy plate was subjected to cathodic electrolytic treatment at a current density of 10 A / dm ² using the treatment liquid of No. ¹ , and washed with water and dried.
The amount of the chromate film adhered was adjusted by controlling the amount of electricity supplied in the cathodic electrolytic treatment.

Organic Resin Table 1 shows the block urethane-modified epoxy resin used in this example and the resin used as a comparative example. In addition, the block urethane modified epoxy resin No. 1 to N
o. No. 14 was prepared 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 a bisphenol A type epoxy resin having an epoxy equivalent of 1500, 385 parts of xylene, and cyclohexanone 3
85 parts were added and heated and dissolved under stirring. Further, 20 parts of isopropanolamine was added and reacted at 100 ° C. for 5 hours.
2,4-tolylene diisocyanate and octyl alcohol adduct monoisocyanate 65 parts
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 1,000 and 125 parts of xylene were heated at 60 ° C. with stirring, and 2,6-
153 parts of tolylene diisocyanate were 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 the NCO% was 0, 175 parts of butanol was added to obtain 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 2,000, 300 parts of xylene and 87 parts of 2,6-tolylene diisocyanate under the same apparatus and reaction conditions. Further, 57 parts of ε-caprolactam were added, the reaction was continued, and after confirming that the NCO% was 0, 129 parts of butanol was added to obtain block urethane B2 having a resin content of 60%. 500 parts of polypropylene glycol having a molecular weight of 4000, 300 parts of xylene, and 42 parts of hexamethylene diisocyanate under the same apparatus and reaction conditions.
An NCO% of 1.2% was obtained from the part. Further, 23 parts of methyl ethyl ketoxime was added to continue the reaction,
After confirming that the CO% was 0, 77 parts of butanol was added to obtain block urethane B3 having a resin content of 60%.

Lubricants Table 2 shows the lubricants used in this example.

Rust preventive additives Table 3 shows the rust preventive additives used in this example.

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

Tables 5 to 14 show the structures of the composite coated aluminum alloy sheets prepared in this example and the evaluation results of corrosion resistance (rust resistance), sharpness, paint adhesion, weldability and scratch resistance. Shown in In addition, the evaluation method of each characteristic is as follows.

A) Corrosion resistance (yarn rust resistance) The test material was treated with zinc phosphate with PBL-3020 manufactured by Nippon Parkerizing Co., Ltd., and then U-6 manufactured by Nippon Paint Co., Ltd.
After electrodeposition coating (25μ) at 00, Kansai Paint Co., Ltd.
An intermediate coat was applied with KPX-36 (30 μm), and a top coat was applied with Lugabake B-531 (Kansai Paint Co., Ltd.) (35 μm). A cross cut was made on these test pieces with a cutter knife, and a filiform rust resistance test was performed in [salt spray test / 24 hours → wet test (40 ° C., relative humidity 85%) / 720 hours], and corrosion from the black cut portion The corrosion resistance (yarn rust resistance) was evaluated based on 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) Visibility The test material was subjected to the same electrodeposition coating, intermediate coating, and top coating as in a) above, and a scalability tester (IC) manufactured by Suga Test Instruments Co., Ltd.
M-2DP) and the image clarity C when using a 0.5 mm slit was evaluated. The evaluation criteria are as follows. ◎: 80 or more ○: less than 80, 75 or more Δ: less than 75, 70 or more ×: less than 70

C) Coating Adhesion The test material was subjected to the same electrodeposition coating, intermediate coating, and top coating as in a) above, and these test pieces were immersed in ion-exchanged water at 40 ° C. for 240 hours. Then, remove the test piece,
After standing at room temperature for 24 hours, the coating was cut into 100 grids at intervals of 2 mm, the cellophane tape was adhered and peeled off, and the coating film was evaluated for the residual ratio. 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), pressure: 270 kgf,
Energizing time: 5 cycles / 50 Hz, welding current: 25 kA
The test was conducted for continuous spotting at JIS Z 31 every 100 shots.
Measurement of tensile shear load based on 36, JIS Z 3140
The number of hit points was evaluated based on the following. 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 The test material was subjected to a scratch test with a sapphire needle (0.05 mmφ) under a constant load using a load-type scratch strength tester, and the load was evaluated at the time when scratches began to be observed. . The evaluation criteria are as follows. ◎: 50 g or more ○: 40 g or more, less than 50 g △: 30 g or more, less than 40 g ×: less than 30 g

F) Press formability Punch: 50 mmφ · R8, Die: 53 mmφ · R
5. Blank diameter: 110mmφ, BHF: 3.6 ton
Was subjected to deep drawing, and the press formability was evaluated by measuring the forming height until cracking occurred. The evaluation criteria are as follows. ◎: 15 mm or more ○: 14 mm or more, less than 15 mm Δ: 13 mm or more, less than 14 mm ×: less than 13 mm

In Tables 5 to 14, No. 1 to No. In 8, the influence of the chromate treatment was examined. No. 1 and No. 9-No. 29, no. 77, No. At 78
The effect of the resin blended in the organic film was investigated. N
o. 1 and No. 30-No. In No. 42, the influence of a lubricant compounded in the organic film was examined. No. 1 and No. 43-No. 60, no. In No. 79, the effect of a rust preventive additive blended in the organic film was examined. No.
1 and No. 61-No. 69, no. In No. 79, the influence of a conductive substance blended 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. At 80, the influence 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 Amount of chromate conversion in terms of chromium metal * 3 See Table 1 * 4 Weight% of non-volatile content * 5 See Table 2 * 6 See Table 3 * 7 Non-volatile content Weight ratio * 8 See Table 4. * 9 Aluminum alloy plate with oxide film removed. * 10 Spray degreasing, washing with water and drying of aluminum alloy plate with sodium orthosilicate.
Next, the coating composition was applied by a roll coater and baked.

[0084]

As described above, according to the present invention, excellent press formability is provided while ensuring good sharpness,
In addition, it has excellent yarn rust resistance, scratch resistance, paint adhesion, and can be spot-welded, so that it is extremely useful as an aluminum plate or aluminum alloy plate for automobiles and home appliances. Further, the composite coated aluminum plate or aluminum alloy plate of the present invention suppresses the elution of aluminum into the processing solution during the phosphating treatment, and therefore, is treated simultaneously with the steel plate in the existing automotive phosphating process. However, the formation of the phosphate film on the steel sheet is not hindered by the eluted aluminum. 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.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI C23C 22/00 C23C 22/00 Z C25D 11/38 C25D 11/38 C (72) Inventor Masaaki Yamashita 1-chome Marunouchi, Chiyoda-ku, Tokyo 1-2 Nippon Kokan Co., Ltd. (72) Inventor Toyofumi Watanabe 1-2-1, Marunouchi, Chiyoda-ku, Tokyo 1-2-1 Nippon Kokan Co., Ltd. (72) Inventor Yoshio Kikuta 1900 Togo, Mobara City, Chiba Pref. (72) Inventor Kimio Kobori 1900 Togo, Mobara City, Chiba Prefecture Inside Mitsui Toatsu Chemicals Co., Ltd. (72) Inventor Takashi Yokoyama 1900 Togo Togo, Mobara City, Chiba Prefecture, Mitsui Toatsu Chemicals Inc. (56 References JP-A-2-182717 (JP, A) JP-A-2-303574 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B05D 7/14 101 B05D 3/10 B05D 7/24 301 B05D 7/24 302 B32B 15/08 C23C 22/00 C25D 11/38

Claims (13)

(57) [Claims] 1. A block urethane-modified epoxy resin having a chromate layer of 1 to 150 mg / m ² as a first layer on a surface of an aluminum plate or an aluminum alloy plate as a first layer, and a second layer above the chromate layer. A composite coated aluminum plate or aluminum alloy plate having an organic film having a film thickness of 0.05 to 2 μm and containing an organic film having a thickness of 0.05 to 2 μm and 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% However, weight% of non-volatile content 2. A block urethane-modified epoxy resin having a chromate layer of 1 to 150 mg / m ^{2 in} terms of metal chromium as a first layer on the surface of an aluminum plate or an aluminum alloy plate, and a second layer above the chromate layer as a first layer. Press-formed, scratch-resistant, thread-rust-resistant and sharp-image composite coated aluminum plate having an organic film having a film thickness of 0.05 to 2 μm containing a metal and a lubricant and a rust-preventive additive. 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, non-volatile content by weight 3. A block urethane-modified epoxy resin having a chromate layer as a first layer on the surface of an aluminum plate or an aluminum alloy plate as a first layer in an amount of 1 to 150 mg / m ^{2 in} terms of chromium metal, and a second layer above the chromate layer. Molded Aluminum Plate or Aluminum Having an Organic Film with a Film Thickness of 0.05 to 2 μm Containing Oil, Lubricants and Conductive Substances and Excellent in Press Formability, Scratch Resistance, Yarn Rust Resistance and Brightness 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 components 4. A block urethane-modified epoxy resin having a chromate layer as a first layer on the surface of an aluminum plate or an aluminum alloy plate as a first layer in the range of 1 to 150 mg / m ^{2 in} terms of chromium metal, and a second layer thereon as a second layer. Thickness containing 0.05%, a lubricant, a rust preventive additive, and a conductive substance
A composite coated aluminum plate or aluminum alloy plate having an organic coating of 2 μm and 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, the weight percentage of non-volatile components 5. The lubricant according to claim 1, wherein the lubricant constituting the organic film is at least one lubricant selected from the group consisting of fluororesin, graphite and boron nitride. 2. A composite coated aluminum plate or aluminum alloy plate excellent in press formability, scratch resistance, yarn rust resistance and sharpness described in 1. 6. The rust preventive additive constituting the organic film comprises at least one rust preventive additive selected from the group consisting of silica and chromate. A composite coated aluminum plate or aluminum alloy plate excellent in press formability, scratch resistance, yarn rust resistance and sharpness. 7. The press-molding property according to claim 6, wherein the rust-preventive additive constituting the organic film comprises silica and chromate in the following proportions, and is excellent in flaw rust resistance and sharpness. Composite coated aluminum plate or aluminum alloy plate. Silica / chromate = 90/10 to 10/90 (weight ratio) 8. A block urethane comprising a polyethylene glycol, a polyisocyanate and a blocking agent, wherein a block urethane-modified epoxy resin constituting an organic film is a modified epoxy resin (A) obtained by modifying an epoxy resin with a polyfunctional amine (B). A / B = 95/5 to 50/5
The press-formability according to claim 1, claim 2, claim 3, claim 4, claim 5, claim 6, claim 6 or claim 7, wherein the block urethane-modified epoxy resin is mixed at a ratio of 0 (weight ratio). A composite coated aluminum plate or aluminum alloy plate with excellent scratch resistance, thread rust resistance and sharpness. 9. A surface of an aluminum plate or an aluminum alloy plate having a chromate layer as a first layer having a thickness of 1 to 150 mg / m ^{2 in} terms of metal chromium, and a second layer above the chromate layer as a block urethane-modified epoxy resin: 80 wt% Lubricant: 5 to 60 wt%, provided that the block urethane-modified epoxy film is a 0.05 to 2 μm-thick organic film containing a block urethane-modified epoxy resin and a lubricant in a proportion of non-volatile content by weight. The resin is a modified epoxy resin (A) obtained by modifying an epoxy resin with a polyfunctional amine, and a block urethane (B) comprising a polyethylene glycol, a polyisocyanate and a blocking agent is added to A /
B = a block urethane-modified epoxy resin mixed at a ratio of 95/5 to 50/50 (weight ratio), wherein the lubricant is selected from one or more lubricants selected from the group consisting of fluororesins, graphite and boron nitride. A composite coated aluminum plate or aluminum alloy plate having an organic coating and excellent in press formability, scratch resistance, yarn rust resistance and sharpness. 10. A chromate layer as a first layer having a thickness 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 block urethane-modified epoxy resin: 30 to 80 wt% Lubricant: 5 to 60 wt% Rust-preventive additive: 3 to 50 wt% However, a film thickness containing a block urethane-modified epoxy resin in a proportion of nonvolatile content by weight, a lubricant and a rust-preventive additive of 0.05 to 50 wt% A block urethane (B) comprising a polyethylene glycol, a polyisocyanate and a blocking agent with respect to a modified epoxy resin (A) in which the block urethane-modified epoxy resin is an organic film having a thickness of 2 μm and the epoxy resin is modified with a polyfunctional amine; Urethane-modified epoxy resin obtained by mixing A / B at a ratio (weight ratio) of 95/5 to 50/50 And the lubricant is at least one lubricant selected from the group consisting of fluororesin, graphite and boron nitride, and the rust preventive additive is silica / chromate = 90/10 to 10/90. (Weight ratio) A composite coated aluminum plate or aluminum alloy plate excellent in press formability, scratch resistance, thread rust resistance and sharpness, having an organic film composed of silica and chromate in the ratio of (weight ratio). 11. A surface of an aluminum plate or an aluminum alloy plate having a chromate layer as a first layer having a thickness of 1 to 150 mg / m ^{2 in} terms of metal chromium, and a second layer thereon having a block urethane-modified epoxy resin of 30 to 150 mg / m ^2. 80% by weight Lubricant: 5 to 60% by weight Conductive substance: 2 to 40% by weight However, a block urethane-modified epoxy resin having a ratio of non-volatile content by weight of 0.05% to 2 μm in thickness containing a lubricant and a conductive substance. The block urethane (B) composed of polyethylene glycol, polyisocyanate and a blocking agent is added to the modified epoxy resin (A), which is an organic film and the block urethane-modified epoxy resin is obtained by modifying the epoxy resin with a polyfunctional amine. / B = block urethane modified epoxy resin mixed at a ratio (weight ratio) of 95/5 to 50/50 Press formability, scratch resistance, thread rust resistance and freshness, wherein the lubricant has an organic film composed of at least one lubricant selected from the group consisting of fluororesin, graphite and boron nitride. Composite coated aluminum plate or aluminum alloy plate with excellent image quality. 12. A 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 as a first layer, and a 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, the proportion of the non-volatile content by weight of block urethane modified epoxy resin, lubricant and rust preventive additive 0.05-2 μm in thickness including conductive material
And the block urethane-modified epoxy resin is a modified epoxy resin (A) obtained by modifying an epoxy resin with a polyfunctional amine with a block urethane (B) composed of polyethylene glycol, polyisocyanate and a blocking agent. A block urethane-modified epoxy resin mixed at a ratio of A / B = 95/5 to 50/50 (weight ratio), wherein the lubricant is at least one type of lubricant selected from the group consisting of fluororesins, graphite and boron nitride. Moldability, wherein the rust-preventive additive has an organic film composed of silica and chromate in a ratio of silica / chromate = 90/10 to 10/90 (weight ratio). A composite coated aluminum plate or aluminum alloy plate with excellent scratch resistance, thread rust resistance and sharpness. 13. An aluminum plate or an aluminum alloy plate having an oxide film thickness of 100 ° or less, wherein the thickness of the oxide film is 100 ° or less. Claim 8, Claim 9, Claim 10, Claim 11
Or press moldability according to claim 12, scratch resistance,
Composite coated aluminum plate or aluminum alloy plate excellent in thread rust resistance and sharpness.