JP2002030461A - Aluminum-based metal plate with corrosion resistant composite layer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a corrosion-resistant composite layer having bare or post-paint corrosion resistance equal to or higher than that of a conventional chromate film without using hexavalent chromium at all, and further exhibiting excellent workability. Provide an aluminum-based metal plate. SOLUTION: On an aluminum-based metal plate, an intermediate layer having an inorganic colloid and a group IVA compound as main components and a thickness of 0.5 μm or less, and a rare earth compound, an inorganic colloid and a resin as main components on the intermediate layer. An aluminum-based metal plate having a corrosion-resistant composite layer, comprising a resin-based corrosion-resistant layer having a thickness of 0.2 μm or more.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum-based metal sheet having a corrosion-resistant composite layer which is excellent in corrosion resistance after naked or painted without using hexavalent chromium at all, and has excellent ironing or press workability. It is.

[0002]

2. Description of the Related Art Conventionally, in order to improve the corrosion resistance and paint adhesion of aluminum-based metal plates used for automobiles, home appliances, building materials, etc., chromate treatment is generally performed. Examples of the chromate treatment include electrolytic chromate and coating chromate. Electrolytic chromates include, for example, chromic acid as a main component, sulfuric acid,
It has been carried out by subjecting a metal plate to cathodic electrolysis using a bath to which various anions such as phosphoric acid, boric acid and halogen are added. As the coating type chromate, chromic acid in which a part of hexavalent chromium is reduced to trivalent in advance or chromic acid in which the ratio of hexavalent chromium to trivalent chromium is specified is treated with a liquid containing an inorganic colloid or an anion. Are known. Further, a method of combining chromium with an organic polymer to block the chromium in the film and a method of further coating the organic polymer on the chromate film have been considered.

[0003] However, chromate films formed by electrolysis have a low elution of hexavalent chromium, but cannot be said to have sufficient corrosion resistance. In particular, the corrosion resistance after processing when the film is damaged during processing is extremely reduced. I do. In addition, the chromate film formed by the coating type generally contains a soluble hexavalent chromium compound in the film, and exhibits extremely high corrosion resistance. Elution of hexavalent chromium is inevitable, which is not preferable because it causes environmental problems. In order to completely eliminate the adverse effects of hexavalent chromium and obtain an industrially useful metal plate, it is necessary to develop a rust-preventive film having the same function as a conventional chromate film without using hexavalent chromium at all. .

[0004] As such a technique, Japanese Patent Application Laid-Open No. 2-502 is disclosed.
No. 655, which includes a cerium ion disclosed in US Pat.
A method of obtaining a corrosion-resistant coating layer of cerium hydroxide by immersing an aluminum plate in an acidic aqueous solution of about H1 to 3 or cerium ion, zirconium ion, phosphate ion disclosed in JP-A-2-25579; Formation of double salt film on aluminum by fluorine ion
A zinc phosphate film formed with a treatment solution of zinc ions, phosphate ions, and lanthanum compounds disclosed in Japanese Patent No. 331658 is known.

[0005] However, these techniques are not particularly satisfactory in corrosion resistance as compared with an aluminum-based metal plate subjected to chromate treatment. In the case of a coating as disclosed in JP-A-2-502655, a certain degree of corrosion resistance is exhibited immediately after the treatment, but when a defect occurs in the coating in a working or actual use environment, a function of repairing the exposed metal surface is provided. And corrosion progresses. Similarly, in JP-A-2-25579 and JP-A-5-331658, a reaction product of a treatment liquid and a metal plate mainly forms a film, and the function of repairing a film defect generated after the treatment is not sufficient. weak. Further, in the study of the present inventors, it has been recognized that phosphate ions tend to promote pitting of aluminum-based metal plates, and the use of phosphoric acid species on aluminum-based metal plates is preferable from the viewpoint of corrosion resistance. Absent.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a coating having a corrosion resistance of bare or after coating equal to or higher than that of a conventional chromate film without using hexavalent chromium at all, and also having excellent workability. An object of the present invention is to provide an aluminum-based metal plate having the corrosion-resistant composite layer shown.

[0007]

SUMMARY OF THE INVENTION The excellent corrosion resistance of chromate is based on the "barrier function" of an extremely stable compound layer formed when a highly reactive hexavalent chromium-based treatment solution is applied and a metal plate. The soluble hexavalent chromium compound remaining in the film without reacting with the film flows into the film defect generated after the treatment, and is expressed by two functions of a "self-healing function" for forming a new stable barrier layer. In order to provide an aluminum-based metal plate that does not use hexavalent chromium at all and has a function equivalent to that of a conventional chromate-treated aluminum-based metal plate, the barrier function and the self-healing function are each expressed by a compound other than chromium. We thought that this was one of the means, and made intensive studies. As a result, the barrier function is provided in the intermediate layer mainly composed of the inorganic colloid and the group IVA compound near the surface of the aluminum-based metal plate, and the self-healing function is provided in the resin-based corrosion-resistant layer mainly composed of the rare earth compound, the inorganic colloid and the resin. It has succeeded in imparting extremely high corrosion resistance to the aluminum-based metal plate due to the synergistic effect of the two layers.

The gist of the present invention is as follows. (1) An inorganic colloid and I
An intermediate layer having a thickness of 0.5 μm or less containing a VA group compound as a main component, and a resin-based corrosion-resistant layer having a thickness of 0.2 μm or more containing a rare earth compound, an inorganic colloid and a resin as main components on the intermediate layer; An aluminum-based metal plate having a corrosion-resistant composite layer, comprising: (2) The aluminum-based metal plate having the corrosion-resistant composite layer according to (1), further including an interface layer containing a Group IVA compound as a main component and having a thickness of 0.1 μm or less between the aluminum-based metal plate and the intermediate layer. (3) The aluminum-based metal plate having a corrosion-resistant composite layer according to (1) or (2), wherein the IVA group compound is a zirconium compound.

(4) The rare earth compound is yttrium
Rare earth compounds selected from cerium, lanthanum, and cerium
Any one or more of (1) to (3)
An aluminum-based metal plate having the corrosion-resistant composite layer as described above. (5) The inorganic colloid is TiO_Two, Y_TwoO_Three, La
_TwoO_Three, CeO_Two, Al _TwoO_Three, ZrO_Two, And SiO
_TwoOne or more selected from (1) to
Aluminum having the corrosion-resistant composite layer according to any of (4).
Metal plate. (6) The resin-based corrosion-resistant layer further contains a lubricating compound
The corrosion-resistant composite layer according to any one of (1) to (5),
An aluminum-based metal plate having

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. As the type of the aluminum-based metal plate that can be used in the aluminum-based metal plate having the corrosion-resistant composite layer of the present invention, it can be used for all aluminum-containing metal plates. , An aluminum metal plate, an aluminum alloy plate, an aluminum plated steel plate, an aluminum alloy plated steel plate, and the like. The aluminum-based metal plate having the corrosion-resistant composite layer of the present invention, like the chromate-treated metal plate, has a `` barrier function '' that suppresses corrosion promotion factors such as oxygen and chloride ions from reaching the metal plate surface, and after production. It has a "self-healing function" that suppresses corrosion of exposed metal surfaces when it is worked or damaged.

The corrosion-resistant composite layer of the aluminum-based metal sheet having the corrosion-resistant composite layer of the present invention has a laminated structure of an intermediate layer and a resin-based corrosion-resistant layer, or a laminated structure of an interface layer, an intermediate layer, and a resin-based corrosion-resistant layer. I have. The interface layer is a concentrated layer of a group IVA element containing a group IVA compound as a main component, and is present on the surface of the aluminum-based metal plate and has a strong “barrier function”.
Is expressed. Group IVA elements are Ti, Zr and Hf.
This is more than a kind, and Ti, Zr and a mixture thereof are preferable.

The interface layer is made of an aluminum-based metal plate made of IVA.
It is formed when the aluminum-based metal plate is brought into contact with an aqueous solution of a group compound or an intermediate layer treatment liquid for forming an intermediate layer. Although the formation mechanism and the compound to be formed cannot be specified, the I
The VA group compound contacts and reacts with the surface of the metal plate,
It is estimated that hydroxides and oxides of group VA elements are precipitated. Using a microtome or the like, an ultra-thin section in the cross-sectional direction of the metal plate of the present invention is prepared, and a transmission electron microscope (TE
When observed in M), the interface layer can be observed as a concentrated layer of a group IVA element.

The presence or absence of the formation of the interface layer depends on the contacting aqueous solution.
Or the type of IVA compound dissolved in the processing solution
Dependencies, such as H_TwoZrF₆, ZrO (N
O_Three)_Two, H_TwoTiF₆In most cases, formation was observed.
Not, but K_TwoZrF₆, K _TwoTiF₆Etc. are respectively
A thick layer of Zr or Ti is observed. This interface layer exists
Then, especially the corrosion resistance performance is dramatically improved. Of this interface layer
The thickness depends on the aqueous solution of the IVA compound to be brought into contact with
Change the concentration of the physical solution or the temperature at the time of contact
By doing so, the thickness can be controlled.
If m or less, sufficient corrosion resistance can be obtained.

The intermediate layer contains a group IVA compound and an inorganic colloid as main components, and is present on the interface layer or on the surface of the aluminum-based metal plate, which also exhibits a "barrier function". The barrier function is to react with and stabilize the metal plate surface.
The expression was achieved by allowing the group VA compound to be present at a high concentration on the surface of the metal plate. Furthermore, the coexistence of the inorganic colloid enhances the barrier function and extremely improves the corrosion resistance after coating.

The group IVA compound which is a main component of the intermediate layer is at least one compound of Ti, Zr and Hf, and examples thereof include oxides, hydroxides and the like of Ti, Zr and Hf.
Sulfate, nitrate, chloride, carbonate, chloride, nitrate, compounds with hydrofluoric acid or salts thereof, and organic salts and complexes of oxalic acid, formic acid, acetic acid, etc. 1
Or a mixture of two or more kinds, and preferably, an oxide, a hydroxide, a nitrate, a sulfate of Zr,
It is one type or a mixture of two or more types selected from fluorinated zirconate and fluorinated zirconate.

In addition, the inorganic colloid, which is another main component of the intermediate layer, forms a dense layer together with the coexisting group IVA compound to enhance the barrier function,
It is estimated to be effective to enhance the adhesion of the metal sheet surface or interfacial layer and the resin-based corrosion-resistant layer, TiO _2, Y
₂ O ₃ , La ₂ O ₃ , CeO ₂ , Al ₂ O ₃ , Zr
One type or a mixture of two or more types selected from O ₂ and SiO ₂ can be used. The particle diameter of the inorganic colloid is preferably 0.2 μm or less from the viewpoint of corrosion resistance, and is preferably 0.1 μm or less in consideration of ironing workability and the like.

The composition ratio of the IVA group compound and the inorganic colloid in the intermediate layer varies depending on the type of the aluminum-based metal plate used and the use of the metal plate, and it is difficult to specify the composition in general. Has an IV in the middle layer
It is preferable that the content of the group A compound is 1 wt% to 90 wt% and the content of the inorganic colloid is 10 wt% to 99 wt%. When long-term corrosion resistance or corrosion resistance after coating with a paint is required, the intermediate layer is required. Group IVA compound content of 1
0wt% ~ 80wt%, content of inorganic colloid is 20w
It is preferable that the content be t% to 90% by weight.

It is necessary to find an optimum value for the thickness of the intermediate layer depending on the type of the aluminum-based metal plate to be used and the use of the metal plate. In order to satisfy the generally required corrosion resistance, paint adhesion, and the like, the thickness is preferably 0.01 μm or more and 0.5 μm or less. If it is less than 0.01 μm, the effect of inhibiting the corrosion of the intermediate layer becomes difficult to recognize, and if it is more than 0.5 μm, the adhesion of the paint may be insufficient. Further, in order to satisfy weldability, workability, etc., the thickness is preferably 0.2 μm or less, and 0.2 μm or less.
If it exceeds m, the coating may be discolored when welding is poor or when processing is performed. The resin-based corrosion-resistant layer contains a rare-earth compound, an inorganic colloid, and a resin as main components, exists on the intermediate layer, and mainly exhibits a “self-healing function”.

The self-healing function is exhibited by allowing a soluble rare earth compound to be present in the resin-based corrosion-resistant layer. In other words, the rare-earth compound contained in the resin-based corrosion-resistant layer flows into film defects generated by processing, scratches, and the like, and increases the local pH due to the cathodic reaction of the corrosion reaction (mainly the reduction reaction of oxygen), thereby causing hydroxide or oxidation. The deposited film serves as a barrier for a corrosion reaction, and further suppresses the progress of corrosion. All kinds of salts and complexes except the hydroxides and oxides of rare earth elements exhibit such behavior and can be applied to the technology of the present invention, but effective phosphates and hydrogen phosphates on the surface of zinc and iron. Cannot be used on the surface of an aluminum-based metal plate to promote pitting. Rare earth element chlorides, nitrates, sulfates, acetates, organic acid salts, complexes with organic compounds, and the like are preferable from the viewpoint of solubility and economy. As the rare earth element, yttrium, lanthanum, and cerium are preferable in terms of economy considering the distribution of the rare earth metal element and the like, and cerium which becomes stable and dense CeO ₂ when precipitated is most preferable.

The inorganic colloid, which is one of the main components of the resin-based corrosion-resistant layer, holds the rare-earth element in the resin-based corrosion-resistant layer together with the resin and suppresses the permeation of substances such as corrosion promoting factors. It has an effect on the properties and is an essential component for the present invention. Inorganic colloids that can be used in the present invention include TiO ₂ , Y ₂ O ₃ , La ₂ O ₃ , C
One type or a mixture of two or more types selected from eO ₂ , Al ₂ O ₃ , ZrO ₂ , and SiO ₂ can be used. The average particle size of the inorganic colloid is preferably 0.2 μm or less from the viewpoint of corrosion resistance, and is preferably 0.1 μm or less in consideration of ironing workability and the like.

The resin which is one of the main components of the resin-based corrosion-resistant layer is not particularly limited as long as it can be mixed with other main components and can form a film. Taking into account the working environment and the like when forming the film, an aqueous resin is preferred. In the case of a water-based resin, a curable resin which is a water-soluble resin, contains a crosslinking agent in a coating material, and is cured by the crosslinking agent at the time of film formation treatment and becomes water-insoluble is more preferable. Alternatively, a water-insoluble copolymer having a high affinity for water and having a molecular skeleton that adheres to the surface of the material, such as adsorption and hydrogen bonding, and a balance composed of a molecular skeleton having no affinity for water. Resins and telechelic resins or core-shell emulsion resins are more preferred.

The reason why a resin having such a structure is preferable is that the resin is mixed with a rare earth metal element compound or an inorganic colloid which coexists in the processing solution, and has a gas barrier property after forming a film. This is because a stable property as a corrosion resistant layer such as ion permeability, paint adhesion, fingerprint resistance, adhesion to an intermediate layer surface and workability is exhibited. In particular, a resin having such a structure has a long-term water resistance due to a network of molecular skeletons having no affinity for water, and a molecular skeleton having affinity for water that is partially present, This is because water is absorbed when water enters in a corrosive environment, helps dissolution of the rare earth compound, and effectively acts as a place where a self-healing function is developed.

Therefore, it is desirable to have such a resin structure. The resin composition of the water-insoluble copolymer resin is a copolymer resin containing a vinyl or olefin compound as a monomer. It is produced by various polymerization methods of solution, bulk, interface, suspension and emulsion. The main skeleton is a polymer of non-hydratable vinyl and olefin monomers, with water at both ends, vinyl carboxylic acid, vinyl amine, vinyl sulfonic acid, and vinyl alcohol with high affinity for metal surfaces. , A copolymer resin composed of an organic polymer such as vinyl phenol, or a chain transfer agent in the process of polymerizing the non-hydratable skeleton portion, water and an affinity group with the metal surface were introduced at both ends. Examples include telechelic resins or emulsion resins in which a polymer of a non-hydratable vinyl or olefin monomer is used as a core phase, and a polymer of a monomer having high affinity for water and a metal surface is used as a shell phase.

In the case of these copolymer resins and core-shell emulsion resins, the mass ratio of the skeleton having high affinity to water or the surface of the intermediate layer to the non-hydratable skeleton is as follows:
To ensure the adhesion to the surface of the intermediate layer, higher is desirable, but if it is too high, the water absorption increases, and it is not preferable because the film peels off due to water swelling, and if it is too low, the paint adhesion is impaired. Not preferred. Therefore, the mass ratio (skeleton having high affinity for water or the surface of the intermediate layer / non-hydratable skeleton) is 3/100 to 3/2, preferably 1/20 to 100.
It is desirable to adjust to 1/1. In the case of a water-soluble resin, a water-soluble resin or a copolymer of a water-soluble vinyl monomer and a water-insoluble vinyl monomer composed of a polymer of a water-soluble vinyl monomer or a polymer of a water-soluble vinyl monomer. Is a water-soluble vinyl resin composed of: a resin having a crosslinkable functional group (unsaturated bond, etc.) in its skeleton, and a curing agent causing cross-linking between polymer molecules and becoming water-insoluble. Is used.

As the water-soluble vinyl monomer, a polar group-containing monomer can be used. This polar group is represented by -C
_{OOH, -SO 3 H, -P (} OH) 2 O, proton donating groups such as -OH, or their salts or esters, and, -
Proton-accepting groups such as NH ₂ , —NHR, and —NRR ′ (R and R ′ are alkyl groups or allyl groups);
It refers to a quaternary ammonium base having an ionic bond, or an amphoteric polar group in which a proton donating / accepting group is mixed, and a vinyl compound into which one or more of these polar groups are introduced can be used as a monomer. The water-insoluble vinyl monomer may be one or two selected from styrene, α-methylstyrene, vinyltoluene, chlorostyrene, alkyl (meth) acrylate, allyl (meth) acrylate, and the like. More than species can be used.

The introduction of the water-insoluble vinyl polymer skeleton is performed to adjust the total water solubility of the polymer and to adjust the degree of crosslinking at the time of curing. However, it is desirable to adjust the introduction amount so that the solubility of the polymer as a whole in water is 5 wt% or more, preferably 10 wt% or more at 25 ° C. and normal pressure. Polymers can be produced using one or more of these monomers. Furthermore, the above functional group may be introduced into the water-insoluble polymer to make it water-soluble. As the cross-linking agent, general amines, carboxylic acids, blocked isocyanates, etc. can be used, and crosslinks are formed between polymer backbones by forming urethane bonds, acid amide bonds, ester bonds, etc. I do.

The composition ratio of the various components of the resin-based corrosion-resistant layer depends on the type and use of the aluminum-based metal plate, and the optimum composition ratio can be appropriately selected. In the case where the corrosion resistance or the corrosion resistance of a cut surface of a metal plate or the like is required, the optimum content range of each main component is exemplified. If the resin is 10 wt% to 90 wt% with respect to the resin-based corrosion-resistant layer in terms of solid content mass. It is preferably 30 wt% to 70 wt% when higher corrosion resistance and paint adhesion in a wet environment are also required. The rare earth metal element compound is preferably 0.5 wt% to 60 wt% with respect to the resin-based corrosion resistant layer in terms of the rare earth metal, and more preferably 5 wt% to 40 wt% when higher corrosion resistance and paint adhesion are also required. Inorganic colloid, one of the main components, is 5 wt% to 80 wt% in terms of solid content.
Is preferable, and when severe processing is also performed, 5 wt% to 5 wt%
0 wt% is more preferable.

The lubricating compound has a function of imparting lubricity by reducing the friction coefficient of the surface, preventing galling and the like, and improving workability such as press workability and ironing workability. The lubricating compound may be any compound that imparts lubricating performance to the resulting film, and may be polyolefin (polyethylene, polypropylene, etc.), fluorine (polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride, polyfluoride). Vinyl chloride, etc.), paraffin-based, and stearic acid-based waxes.

When the lubricating compound is in the form of particles, the average particle diameter is preferably 5 μm or less. If it exceeds 5 μm, the continuity and uniformity of the coating film will be lost, the adhesion between the resin-based corrosion-resistant layer and the undercoat will be reduced, and the adhesion with the top coating material will be reduced, as will the storage stability as a treatment liquid. The more preferred average particle size of the lubricating compound is in the range of 0.5 to 4 μm. The amount of the lubricating compound to be added is preferably 1 to 30% by weight based on the solid content of the resin-based corrosion-resistant layer. If it is less than 1 wt%, the required lubricating effect cannot be obtained. If it exceeds 30% by weight, there are problems such as a decrease in film strength and peeling of a lubricating compound. The more preferable content of the lubricating compound is 5 to 5.
It is within the range of 20 wt%.

The thickness of the resin-based corrosion-resistant layer containing a rare-earth compound, an inorganic colloid, and a resin as main components may be 0.2 μm or more for general corrosion-resistant use. 5 μm or more is preferred. Economically, a chemical conversion treated metal plate such as a chromate treated metal plate can be sufficiently substituted if it is 5 μm or less, and 2 μm or less is sufficient for applications requiring a certain degree of conductivity such as welding. .

As long as the intermediate layer and the resin-based corrosion-resistant layer of the present invention are formed, the method of forming the film is not limited. For example, a method in which the intermediate layer and the resin-based corrosion-resistant layer are each applied using a roll coater or the like, or a method in which a treatment liquid is brought into contact with a metal plate by spraying or dipping and adjusted to an appropriate film thickness with a ringer roll or an air knife. And a method of combining these. In particular, when a resin-based corrosion-resistant layer is formed using an aqueous treatment solution, care must be taken in preparing the treatment solution so that the rare earth compound does not precipitate as a hydroxide or oxide in the treatment solution. When a salt is used as the rare earth compound, the pH of the treatment liquid is preferably set to 7.5 or less, and taking into account long-term stability,
The following is preferred. When used at a pH of more than 7.5, it is necessary to devise stabilization such as complexation so that the rare earth compound does not precipitate as a hydroxide or an oxide in the treatment solution.

The ligands effective for complexing include:
= 0, -OH, -COOH, -NH _Two, = NH, = N
-, -SH, -SO_ThreeOne or more functional groups selected from H
Is preferable in the molecule. Further, -NH
_Two, = NH, = N- at least one basic function
Group and -SH, -OH, -COOH, -SO_ThreeChoose from H
Organic compounds containing one or more acidic functional groups in the molecule
Corrosion inhibition effect on ligand itself by using
To enhance the anticorrosion performance. More preferred
Or -NH_Two, = NH, = N-
The above basic functional group and -SH, -OH, -COOH, -S
O_ThreeH contains two or more acidic functional groups selected from
Organic compounds.

Since such an organic compound has an adsorbing property on the metal surface, after the rare earth metal is supplied to the surface of the metal plate, the rare earth metal is adsorbed and stabilized on the metal plate, and the ionization of the metal constituting the metal plate proceeds. Has the effect of suppressing Examples of these include derivatives of salicylic acid and phthalic acid, derivatives of nicotinic acid, thioglycolic acid esters, mercaptocarboxylic acids, N-substituted derivatives of 2,5-dimethylpyrrole, derivatives of 8-hydroxyquinoline, derivatives of triazinethiol, Ester derivatives of gallic acid, and the like.

[0034]

Next, the present invention will be described by way of examples. 1. Test materials (1) Types of metal plates The following materials were used as metal plates to be used as substrates. AL: aluminum metal plate (plate thickness 0.8 mm) ALA: hot-dip aluminum-silicon alloy plated steel plate (plate thickness 0.8 mm, coating weight 120 g / m ² , Al / Si mass ratio in plating layer 90/10)

(2) Formation and Composition of Corrosion Resistant Composite Layer Tables 1 to 3 show the composition and film thickness of the prepared corrosion resistant composite layer. Using a microtome, create an ultra-thin section in the cross-sectional direction of the aluminum-based metal plate on which the corrosion-resistant composite layer was formed,
The average film thickness of each of the interface layer, the intermediate layer, and the resin-based corrosion-resistant layer was measured using a transmission electron microscope (TEM).
The average film thickness was determined by selecting an appropriate magnification (20,000 times, 100,000 times, 500,000 times) and calculating the average value of 10 visual fields.

The method for forming each layer and the chemicals used are described below. <Interface layer> The thickness of the interface layer of 0.02 μm or less was changed by changing the K ₂ ZrF ₆ concentration of the intermediate layer treatment liquid. In the case of a Zr-enriched interface layer having a film thickness of more than 0.02 μm, 0.05 mol / l of K ₂ Zr kept at 80 ° C.
It was prepared by immersing a metal plate in an aqueous solution of F ₆ . <Intermediate layer> The intermediate layer dissolves the following appropriate amounts of the following drugs in water,
Alternatively, an intermediate layer treatment solution was prepared by dispersing the solution, applied with a roll coater, and dried under the condition that the surface temperature of the metal plate reached 80 ° C. to prepare the solution. The chemicals used in the intermediate layer treatment liquid are shown below.

· Group IVA compound: H_TwoZrF₆(Trial
Medicine: Aldrich), K_TwoZrF₆ (Reagent: Kanto Chemical
Manufactured), Zr (SO_Four)_Two(Reagent: manufactured by Kanto Chemical), ZrO
(NO_Three)_Two(Reagent: manufactured by Kanto Chemical), K_TwoTiF₆(Trial
(Kanto Chemical).・ Inorganic colloid (1) SiO_TwoColloid (Nissan Chemical Industries, particle size 0.0
2 μm), CeO_TwoColloids (Rodel Nitta,
Particle size 0.1 μm), Al_TwoO_ThreeColloid (Nissan Chemical Co., Ltd.)
Manufactured using a commercially available colloid solution.
did. (2) Y_TwoO_Three(Reagent: manufactured by Kanto Chemical), La_TwoO_Three(Trial
Drug: Kanto Chemical), ZrO_Two(Reagent: manufactured by Kanto Chemical)
Mix with water to 10wt% and pulverize with ball mill
And used as a colloid solution.

<Resin-based Corrosion-Resistant Layer> The resin-based corrosion-resistant layer is prepared by dissolving or dispersing an appropriate amount of the following chemicals in water to prepare a treatment liquid for the intermediate layer, and applying it with a roll coater. It dried under the conditions which became, and was created. The chemicals used in the treatment liquid for forming the resin-based corrosion-resistant layer are shown below.・ Rare earth compounds (1) Y (NO ₃ ) ₃ , Y (CH ₃ COO) ₃ , Ce
(NO ₃ ) ₃ , YCl ₃ , La ₂ (SO ₄ ) ₂ , La
(NO ₃ ) ₃ , LaCl ₃ , La (C ₂ O ₄ ) ₃ , Ce
As (NO ₃ ) ₃ and CeCl ₃ , reagents (manufactured by Kanto Chemical) were used.

(2) [Ce (HNA) ₄ ] is a complex of tetravalent cerium and 2-hydroxynicotinic acid, the pH of an aqueous solution of 2-hydroxynicotinic acid is adjusted to 7.5, and Ce
It was mixed with an aqueous solution of (NH ₄ ) ₂ (NO ₃ ) _6, and the resulting [Ce (HNA) ₄ ] was filtered, washed with water and dried before use. (3) [Ce (SulPh) ₄ ] is a complex of tetravalent cerium and 4-sulfophthalic acid, and a 4-sulfophthalic acid aqueous solution and a Ce (NH ₄ ) ₂ (NO ₃ ) ₆ aqueous solution at a molar ratio of 4/1. The mixture was refluxed at 80 ° C. for 6 hours, and the resulting aqueous solution of [Ce (SulPh) ₄ ] was used.

Inorganic colloid (1) SiO ₂ colloid (Nissan Chemical Industries, particle size 0.0
2 μm), CeO ₂ colloid (Rodel Nitta)
A commercially available colloid solution was used for the Al ₂ O ₃ colloid (particle diameter: 0.3 μm) and Al ₂ O ₃ colloid (particle diameter: 0.3 μm). (2) Y ₂ O ₃ (reagent: manufactured by Kanto Chemical), La ₂ O ₃ (reagent: manufactured by Kanto Chemical), and ZrO ₂ (reagent: manufactured by Kanto Chemical)
It was mixed with water so as to have a concentration of 10 wt%, pulverized by a ball mill, and used as a colloid solution.

Resin (1) Acrylic resin emulsion having a particle size of 0.2 μm (manufactured by Zeon Corporation, “Acrylic” in Tables 1 and 2) (2) Styrene-butadiene rubber latex having a particle size of 0.13 μm ( The notation "SBR" in Tables 1 and 2) was used. (3) Copolymer resin (notation "copolymer" in Tables 1 and 2)
Used poly (2-hydroxyethyl methacrylic acid) -poly (styrene, n-butyl methacrylate) -poly (methacrylic acid) prepared by living anion polymerization and used.

(4) The telechelic resin (“telechelic” in Tables 1 and 2) is made of poly (styrene, methyl methacrylate, n-butyl methacrylate, n-acrylate).
In the process of anionic polymerization of (-butyl), mercaptopropionic acid, mercaptoethanol and the like were used as a chain transfer agent, and an alcoholic hydroxyl group and a carboxyl group were introduced into the terminal of the acrylic monomer copolymer, prepared and used. (5) Core-shell emulsion resin (Tables 1 and 2)
The notation `` core-shell '') is prepared by emulsion polymerization of a core-shell type resin comprising a styrene-methyl methacrylate-n-butyl methacrylate core phase and a methacrylic acid-2-hydroxyethyl acrylate shell phase, used. (6) Water-soluble resin (notation "water-soluble" in Tables 1 and 2)
Was prepared by adding 2-hydroxyethyl acrylate to deionized water, adding ammonium persulfate as a catalyst, preparing the mixture at 40 ° C., and using it with ethylenediamine as a curing agent.

Lubricating compounds: polyethylene based on Mitsui Chemicals (“PE” in Tables 1 and 2) and fluorine based on Dainippon Ink (“PFT in Tables 1 and 2”)
E ") and a stearic acid type (" StA "in Tables 1 and 2) manufactured by Dainippon Ink. <Comparative material A (chromate treatment)> A coating type chromate solution obtained by adding colloidal silica to chromic acid was applied to the above-mentioned metal plate by a roll coater so that the Cr adhesion amount was 20 mg / m ^2, and dried to form a chromate film. It was formed and used as a comparative material.

<Comparative material B (double salt treatment)>
No. 579, based on Ce (NH_Four)_Two(N
O_Three) ₆To 50 ppm, (NH_Four)_TwoZrF₆50p
pm, H_ThreePO_Four50 ppm and HF were added
HNO and 8 ppm_ThreeAnd ammonia water, p
Prepare a processing solution with H adjusted to 2.7 and keep it warm at 40 ° C.
Spray on the metal plate for 30 seconds, and tap water
After washing for 15 seconds with ion-exchanged water for 15 seconds, 200
It dried at 30 degreeC for 30 second, and was set as the comparative material.

<Comparative material C (zinc phosphate treatment)>
Based on the example of JP-A-331658, 1.0 g / l of Zn ions, 15.0 g / l of PO ₄ ions, and La (N
O ₃ ) ₃ is 0.6 g / l in terms of La metal, 0.6 g / l of Mn ions, 0.6 g / l of Co ions, 0.3 g / l of HF equivalent concentration, 0.8 g / l of SiF ₆ ions, NO _A zinc phosphate treatment solution containing 0.14 g / l of ₂ ions and 6.0 g / l of NO ₃ ions was prepared, and the above metal plate was immersed in the same at 40 ° C. for 2 minutes. Rinse with deionized water for 15 seconds, dry at 100 ° C for 10 minutes,
This was used as a comparative material.

[0046]

[Table 1]

[0047]

[Table 2]

[0048]

[Table 3]

2. Performance evaluation method (1) Bare corrosion resistance test and evaluation method A part of the metal plate on which the corrosion resistance composite layer was formed was subjected to Erichsen processing (6 mm), and a salt spray test was performed until the rust generation area ratio reached 5%. Was measured. The evaluation criteria were: ：: 300 hours or more, ：: 240 hours to less than 300 hours, Δ: 120 hours to less than 240 hours, ×: less than 120 hours.

(2) Corrosion resistance test after coating and evaluation method A melamine-alkyd paint was applied to a metal plate on which a corrosion-resistant composite layer was formed so as to have a thickness of 20 μm. Perform a spray test,
The time until the swollen width from the cross cut became 5 mm was measured. The evaluation criteria were: ：: 500 hours or more, ：: 300 hours to less than 500 hours, Δ: 100 hours to less than 300 hours, ×: less than 100 hours.

(3) Deep drawing test Using a mold having a clearance of + 6% on a metal plate having a thickness of 0.8 mm, primary forming of a wrinkle suppressing pressure of 3 ton, a forming height of 50 mm and a blank diameter of 170 mm. After that, secondary molding was performed using a mold having a clearance of -10% with respect to the original thickness of 0.8 mm. At this time, the presence or absence of a coating component adhering to the punch and the die, and the appearance of the processed surface of the workpiece were observed. The evaluation criteria are as follows: ◎: No coating component adhered to the punch and die, no scratches and discoloration on the surface of the workpiece, ○: A very small amount of coating component adhered to the punch and die, very small on the surface of the workpiece There are slight scratches and discoloration. Δ: Punches and dies have film components adhered to them, and the surface of the workpiece has scratches and discoloration. ×: Punches and dies have very many film components adhered. It was determined that there were severe scratches and clear discoloration on the workpiece surface.

[0052]

[Table 4]

[0053]

[Table 5]

[0054]

[Table 6] The evaluation results are shown in Tables 4 to 6. The examples of the present invention exhibit bare corrosion resistance, corrosion resistance after painting, and deep drawing workability that are equal to or higher than those of the comparative examples.

[0055]

As described above, the aluminum-based metal plate having the corrosion-resistant composite layer of the present invention does not use hexavalent chromium at all and has bare corrosion resistance and post-paint corrosion resistance equivalent to or higher than that of the conventional chromate film. And also has excellent deep drawing workability.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C23C 22/83 C23C 22/83 28/00 28/00 C 28/04 28/04 (72) Inventor Shoji Hiromasa 20-1 Shintomi, Futtsu-shi, Chiba F-term in the Technology Development Division of Nippon Steel Corporation (Reference) 4F100 AA00B AA00C AA17B AA17C AA19 AA19B AA19C AA20 AA20B AA20C AA21B AA21C AA27B AA27C AB01B AB13 ABB AK01C AK04H AK18H AK25 AK25J AK73 AL01 BA03 BA04 BA07 BA10A BA10C CA19C EH46 EH71 GB07 GB32 GB48 JA20B JA20C JA20D JB02 JB02C JL01 JM01B JM01C YY00B YY00C YY00A4 A0A02A4 A0A02 A4A BA10 BA11 BA20 BA21 BB03 BB04 BC02 BC05 CA11 CA16 CA53

Claims (6)

[Claims] 1. An intermediate layer having a thickness of 0.5 μm or less mainly composed of an inorganic colloid and a group IVA compound on an aluminum-based metal plate, and a rare earth compound, an inorganic colloid and a resin being mainly composed on the intermediate layer. An aluminum-based metal sheet having a corrosion-resistant composite layer, comprising a resin-based corrosion-resistant layer having a thickness of 0.2 μm or more. 2. The aluminum-based metal plate having a corrosion-resistant composite layer according to claim 1, further comprising an interface layer containing a Group IVA compound as a main component and having a thickness of 0.1 μm or less between the aluminum-based metal plate and the intermediate layer. . 3. The aluminum-based metal plate having a corrosion-resistant composite layer according to claim 1, wherein the group IVA compound is a zirconium compound. 4. The aluminum-based metal plate having a corrosion-resistant composite layer according to claim 1, wherein the rare-earth compound is one or more rare-earth compounds selected from yttrium, lanthanum, and cerium. . 5. The method according to claim 1, wherein the inorganic colloid is TiO ₂ , Y ₂ O
₃ , having at least one selected from La ₂ O ₃ , CeO ₂ , Al ₂ O ₃ , ZrO ₂ , and SiO ₂ , having a corrosion-resistant composite layer according to claim 1. Aluminum-based metal plate. 6. The aluminum-based metal plate having a corrosion-resistant composite layer according to claim 1, wherein the resin-based corrosion-resistant layer further contains a lubricating compound.