JPH05147153A - Laminated metal plate excellent in edge corrosion resistance and adhesion - Google Patents

Abstract

PURPOSE:To obtain the title laminated metal plate by applying Zn-Cr alloy plating and further applying chromate treatment to the alloy plating layer. CONSTITUTION:In a laminated metal plate consisting of a resin layer 4 and metal plate layers 1, 1 holding the resin layer 4 from both surfaces thereof, Zn-Cr alloy plating layers 2, 2 with Cr-content of 1-70wt.% are applied to at least the surfaces bonded to the resin layer 4 of the metal plate layers 1, 1 in an adhesion amount of 0.5-100g/m<2> and chromate treatment is applied to the alloy plating layers 2, 2 in an adhesion amount of 5-150g/m<2> to form chromate layers 3, 3. By this constitution, extremely excellent edge corrosion resistance and adhesion are developed by the synergistic effect with the chromate layers.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lightweight laminated metal sheet in which a resin layer is sandwiched between metals and joined together, and more particularly to a laminated metal sheet excellent in end face corrosion resistance and adhesion.

[0002]

2. Description of the Related Art In recent years, a laminated metal plate has been attracting attention as a metal plate for reducing vehicle weight. As its name implies, a laminated metal plate is a composite metal plate in which both sides of a resin as a core material are sandwiched and joined by two metal plates as skin materials, and they have excellent vibration damping properties, lightweight properties and deep depth. Due to the drawability, etc., the parts for automobiles (dash lower, roof,
In addition to oil pans), it is widely used for home electric appliances, general building materials, covers for industrial machines, etc.

On the other hand, the properties required for a laminated metal plate are corrosion resistance, particularly corrosion resistance against corrosion from the joint interface between the metal plate and resin at the cut surface (hereinafter referred to as end face corrosion resistance).
There is adhesion between the resin and the metal plate. Regarding the corrosion resistance of the outer surface of the laminated metal plate, for example, in the case of members for automobiles, it can be imparted by applying a phosphate treatment and cationic electrodeposition coating after assembly, but the end surface corrosion resistance is
This is not enough. Further, if the adhesiveness of the bonding interface is low, high-level processing cannot be performed, so that the use is greatly limited.

Conventionally, a cold-rolled steel sheet is used as a skin material of a laminated metal sheet, and in order to secure end face corrosion resistance and adhesion,
Chromate treatment has been performed by directly applying a chromate solution to the surface of the steel sheet that is to be joined to the resin layer.
In addition, the present applicant has previously filed Japanese Patent Laid-Open Nos. 58-90950 and 58
-90951, in order to obtain a laminated steel sheet excellent in end face corrosion resistance and weldability, it was proposed to perform galvanizing and chromate treatment.

[0005]

However, in each of the above-mentioned prior arts, both the end face corrosion resistance and the adhesiveness cannot be satisfied, as shown as a comparative example of the examples described later. Therefore, the inventors of the present invention have made repeated studies and found that the surface steel sheet of this type of laminated steel sheet is Zn--C.
It has been found that if an r-plated steel sheet is applied, the end face corrosion resistance and the adhesion are improved. However, even in this case, it was also found that the end face corrosion resistance and adhesion were still insufficient.

Therefore, a main object of the present invention is to provide a laminated metal plate having excellent end face corrosion resistance and adhesion.

[0007]

Means for Solving the Problems The above-mentioned problems are, in a laminated metal plate comprising a resin layer and a metal plate layer sandwiching the resin layer from both sides, on at least the surface of each metal plate layer on the side to be joined with the resin layer. Zn-Cr alloy plating having a Cr content of 1 to 70% by weight was applied at an adhesion amount of 0.5 to 100 g / m ² , and the surface of the alloy plating in contact with the resin layer was subjected to a chromate treatment of 5 to 150 mg. The problem can be solved by applying the coating amount of / m ² .

[0008]

In the laminated metal plate of the present invention, Zn-Cr is formed on at least the surface of each metal plate layer which is the skin material, which is to be joined to the resin layer.
Alloy plating is applied, and chromate treatment is applied on the alloy plating. A metal plate plated with a Zn—Cr alloy is exposed to a corrosive environment and enters water and oxygen even if it is not chromated.
A chromate is formed on the joint surface between the metal plate layer and the resin layer to show excellent end face corrosion resistance and adhesion. The laminated metal sheet of the present invention, which has been subjected to chromate treatment, exhibits remarkably excellent end face corrosion resistance and adhesion without waiting for formation of the chromate coating and due to the synergistic effect with the chromate coating.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in more detail below with reference to embodiments shown in the drawings. FIG. 1 is a cross-sectional view showing an example of a layered structure of a laminated metal plate of the present invention. Reference numerals 1 and 1 are base metal plates as a skin material, 4 is a resin layer, and this resin layer 4 is a base metal plate 1, 1. Sandwiched by. Further, the Zn—Cr alloy plating layer 2 is formed on the surface of the base metal plate 1, 1 to be joined to the resin layer 4, and the chromate layer 3 formed on the surface thereof.
Bonding with the resin layer 4 is carried out via.

As the base metal plates 1 and 1, cold-rolled steel plates are sufficient, but not only plated steel plates such as zinc-plated steel plates and aluminum-based plated steel plates, but also metal plates such as stainless steel, copper and aluminum can be used. .. Also, the base metal plate 1,
1 does not necessarily have to be the same kind, and may be a combination of different kinds of metal plates such as a galvanized steel plate and an aluminum plate depending on the application. Here, the galvanized steel sheet is meant to include both a pure galvanized steel sheet and a zinc alloy plated steel sheet, and is either an electroplated steel sheet, a hot dip plated steel sheet, an alloyed hot dip plated steel sheet, or a molten salt electrolytic plated steel sheet. May be. As the alloy component of the zinc alloy plated steel sheet, at least one selected from Fe, Ni, Al, Mn, Mg, Co and the like may be used. As an aluminum-based plated steel sheet, for example, 55Al-Z
Examples include n-plated and Al-plated steel sheets. When these plated steel sheets are used as the base metal plates 1 and 1, the coating weight is not particularly limited, but usually 10 to 100 g / m ² is preferable. Further, the thickness of the base metal plates 1 and 1 is 0. 0 from the viewpoint of vibration damping property, workability, and lightness required for laminated steel plates.
It is preferably about 2 to 0.8 mm.

In manufacturing the laminated metal sheet of the present invention, first, on the surface of the base metal sheet 1, 1 to be joined to the resin layer 4,
Zn-Cr alloy plating 2 and 2 are applied. In this case, Zn-
If the adhesion amount of the Cr alloy plating 2, 2 is too small, sufficient corrosion resistance cannot be obtained. Therefore, at least 0.5 g / m ² or more, preferably 1 g / m ² or more of the Zn—Cr alloy plating 2, 2 is adhered. Quantity is needed. On the contrary, if the amount of Zn—Cr alloy plating 2 or 2 deposited is too large, not only the corrosion resistance is not improved, but it is also disadvantageous in terms of the scale of the production line and the economy. The specific adhesion amount depends on the type of the base metal plates 1 and 1, Z
It depends on the Cr content of the n-Cr alloy platings 2 and 2 and the degree of corrosiveness of the usage environment. When the base metal plate 1, 1 is used at a fairly highly corrosive environments cold rolled steel sheet is usually 10 to 50 g / m ^2, in practice is sufficient 20 g / m ² or less. When used in a mild corrosive environment, even if the base metal plates 1 and 1 are cold rolled steel plates, Zn-C
The amount of the r alloy plating 2 or 2 deposited may be 10 g / m ² or less, and particularly 5 g / m ² or less. In this way, the adhesion amount of the Zn—Cr alloy platings 2 and 2 may be determined so as to ensure the required end face corrosion resistance according to the environment of use and the Cr content.

When the base metal plates 1, 1 are zinc-based or aluminum-based plated steel plates, the plating is already present.
End face corrosion resistance is sufficiently secured by ultra-thin plating of g / m ² or less, particularly 5 g / m ² or less. Especially when a galvannealed steel sheet is used among the zinc-based plated steel sheets, the corrosion resistance is further improved due to the high corrosion resistance of the metal plate itself, particularly the perforation resistance.

On the other hand, C in Zn--Cr alloy platings 2 and 2
If the content of r is too low, it will cause deterioration of the end face corrosion resistance and adhesion, and if it is too high, the base metal sheet 1,
There is a problem that the adhesion between No. 1 and the platings 2, 2 is reduced. For this reason, the Cr content is 1 to 70% by weight.
The range is. A desirable range for commercialization is 10
It is about 30% by weight. Further, as the third element, for example, one or more elements such as Al, Ni, Co, Sn, etc. may be used in a small amount within a range that does not impair the characteristics such as corrosion resistance.
That is, the content may be 5 wt% or less, and this case is also within the scope of the present invention.

To apply the Zn-Cr alloy platings 2, 2 to the base metal plates 1, 1, for example, an electroplating method using an acid bath or a vapor deposition plating method can be adopted. Also, this Zn
The -Cr alloy plating 2, 2 is always performed on the surface of the base metal plate 1, 1 that is to be joined to the resin layer 4, but the base metal plate 1, 1
The type of plating is not particularly limited for the non-bonding surface with the resin layer 4, that is, the outer surface of the laminated metal plate.
It may be determined in consideration of the corrosion resistance, workability, spot weldability, paintability, etc. required for each application. By the way,
These characteristics can be satisfied by applying the Zn-Cr alloy platings 2 and 2 to both surfaces of the base metal plates 1 and 1.

Next, the base metal plates 1, 1 are plated with Zn--Cr alloy platings 2, 2 and then the chromate treatment is performed on the Zn--Cr alloy platings 2, 2 to obtain the chromate layers 3, 2. 3 is formed. In this case, chromate 3,3
If the amount of adhesion is too small, sufficient corrosion resistance cannot be obtained. Therefore, at least 5 mg / m ^{2 of} metal Cr, preferably 10 mg / m ² or more of chromate 3,3 is necessary. On the other hand, if the amount of chromate 3, 3 adhered is too large, not only the adhesiveness is not improved so much, but it is also disadvantageous from the viewpoint of the scale of the production line and the economical aspect. The specific amount of adhesion is the type of base metal plate 1, 1, C of Zn-Cr alloy plating 2, 2.
It depends on the r content and the degree of corrosiveness of the operating environment. When the base metal plates 1 and 1 are cold-rolled steel plates and are used in a highly corrosive environment, the amount is usually 5 to 100 mg / m ² ,
About 80 mg / m ² is sufficient for practical use. When used in a mildly corrosive environment, the chromate deposition amount may be 50 mg / m ² or less even if the base metal plates 1 and 1 are cold rolled steel plates. In this way, the amount of chromate 3,3 deposited may be determined so as to ensure the required end face corrosion and adhesion according to the environment in which it is used and the Cr content of the Zn-Cr platings 2,2.

As the chromate treatment method for allowing the chromate layers 3 and 3 to exist between the Zn--Cr alloy platings 2 and 2 and the resin layer 4, various industrially practicable methods can be adopted. For example, a coating method, an electrolysis method and the like can be mentioned. Further, the Zn-Cr alloy plating layers 2 and 2 are applied not only to the ordinary manufacturing method in which the Zn-Cr alloy plating 2 and 2 surfaces are treated and then bonded to the resin 4, but also to the chromate-treated resin 4 surface. A manufacturing method of joining can also be adopted. Further, when it is used for a building material or the like, the non-bonding surface of the base metal plates 1, 1 with the resin layer 4, that is, the outer surface of the laminated metal plate is subjected to chromate treatment so that it becomes a coated surface or a resin film coated surface. can do.

In this way, Zn--Cr alloy plating 2, 2
Is applied, and chromate 3, 3 is applied on the alloy plating 2, 2.
A resin 4 is sandwiched between two treated base metal plates 1 and 1 and laminated by heating, pressure bonding and cooling to obtain a laminated metal plate excellent in end face corrosion resistance and adhesion. Be done. The bonding may be performed using an adhesive or an adhesive film, or the surfaces of the resin layers 4 and 4 may be modified in advance in order to improve the adhesiveness.

The material of the resin 4 is not particularly limited, and examples of useful core resin include a polyolefin-based resin, a polyester-based resin, a polyurethane-based resin, a polyvinyl-based resin, etc., which have relatively high flexibility. There are plastic resins, and polyolefin resins such as polyethylene are typical. The thickness of the resin layer 4 varies depending on the use, but is usually 10 μm to 5 m
m. The resin layer 4 may be a resin film formed in advance, or it may be coated on the spot by coating a liquid resin on the chromate layers 3 and 3 on the base metal plates 1 and 1 with a roll coater or the like. It may be formed. Also, to enable spot welding, disperse conductive powder in resin.
It may be contained.

(Experimental Example) The effect of the present invention will be clarified below by an experimental example. Note that this is an example of the present invention, and the present invention is not limited to this. [Example 1] A cold-rolled steel sheet having a thickness of 0.2 mm was plated with Zn-Cr alloy having the Cr content and the deposition amount shown in Table 1 on both sides by an electroplating method. Then, a chromate film was formed by a coating method and dried at 140 ° C. for 30 seconds to prepare a metal plate as a skin material. On the other hand, as the core resin, a 0.4 mm thick maleic anhydride-modified polyethylene film was prepared. Both sides of this polyethylene film were sandwiched between the two metal plates and thermocompression bonded to produce a laminated metal plate. The hot pressing is performed by using a hot press at a pressing temperature, a pressing force and a pressing time of 150 ° C. and 30 °, respectively.
It was carried out with a kgf of 15 minutes. 3 of the produced laminated metal plates
It was cut into a size of 0 mm × 150 mm, and the end face corrosion resistance and adhesion were evaluated.

The end face corrosion resistance was evaluated by salt spray test (JI
SZ2371) after spraying salt water for 500 and 2000 hours, the metal plates on both sides of the test piece were peeled off, and the progress length of corrosion was measured. The evaluation was performed according to the following criteria. ×: Corrosion progression length after 500 hours was over 5 mm △: Corrosion progression length after 500 hours was 2-5 mm ●: Corrosion progression length after 2000 hours was over 5 mm ○-●: 2000 hours Corrosion progression length after 2 to 5 mm ◯: Corrosion progression length after 2000 hours is less than 2 mm ◎: Corrosion progression length after 2000 hours is less than 1 mm Adhesion is the same as the metal plate measured by the peeling test. The peel strength with the resin was evaluated. The results are shown in Table 1.

[0021]

[Table 1]

Example 2 A 0.2 mm thick cold-rolled steel sheet was plated as shown in Table 2 and then plated with Zn--Cr alloy having the Cr content and the deposition amount shown in Table 2 by electroplating. Applied to Then, as in Example 1, a chromate film was formed by a coating method and dried at 140 ° C. for 30 seconds to prepare a metal plate as a skin material. On the other hand, as the core resin, a 0.4 mm thick maleic anhydride-modified polyethylene film was prepared. Both sides of this polyethylene film were sandwiched between the two metal plates and thermocompression bonded to produce a laminated metal plate. The hot pressing is carried out by using a hot press at a pressing temperature, a pressing force and a pressing time of 150 respectively.
It was carried out at a temperature of 30 kgf for 15 minutes. The produced laminated metal plate was cut into a size of 30 mm × 150 mm, and the end face corrosion resistance and the adhesiveness were evaluated. The evaluations of the end face corrosion resistance and the adhesiveness are the same as in Example 1. The results are shown in Table 2.

[0023]

[Table 2]

Example 3 On a 5% Cr steel plate having a thickness of 0.2 mm, Zn-Cr having the Cr content and the adhesion amount shown in Table 3 was used.
Alloy plating was applied to both sides by electroplating. Then, as in Example 1, a chromate film was formed by a coating method and dried at 140 ° C. for 30 seconds to prepare a metal plate as a skin material. On the other hand, the thickness of the core resin is 0.4
A mm-sized maleic anhydride-modified polyethylene film was prepared. Attach both sides of this polyethylene film to the metal plate 2
It was sandwiched between sheets and thermocompression bonded to produce a laminated metal plate. The thermocompression bonding was carried out by using a hot press at a bonding temperature, a bonding force and a bonding time of 150 ° C., 30 kgf and 15 minutes, respectively. The manufactured laminated metal plate is 30 mm x 150
After cutting into a size of mm, the end face corrosion resistance and the adhesiveness were evaluated. In addition, the evaluation of the end face corrosion resistance and the adhesiveness was performed in Example 1
Is the same as. The results are shown in Table 3.

[0025]

[Table 3]

Example 4 On a cold rolled steel sheet having a thickness of 0.2 mm, the contents of Cr, Al, Ni, Co and Sn shown in Table 4 and the amounts of Zn-Cr- (Al, Ni, Co and Sn) shown in Table 4 were applied. )
Alloy plating was applied to both sides by electroplating. Then, as in Example 1, a chromate film was formed by a coating method and dried at 140 ° C. for 30 seconds to prepare a metal plate as a skin material. On the other hand, the thickness of the core resin is 0.4
A mm-sized maleic anhydride-modified polyethylene film was prepared. Attach both sides of this polyethylene film to the metal plate 2
It was sandwiched between sheets and thermocompression bonded to produce a laminated metal plate. The thermocompression bonding was carried out by using a hot press at a pressing temperature, a pressing force and a pressing time of 150 ° C., 30 kgf and 15 minutes, respectively. The manufactured laminated metal plate is 30 mm x 150
It was cut into a size of mm and the end face corrosion resistance and the adhesiveness were evaluated. In addition, the evaluation of the end face corrosion resistance and the adhesiveness was performed in Example 1
Is the same as. The results are shown in Table 4.

[0027]

[Table 4]

Comparative Example 1 For comparison with Examples 1 to 4, at least one of the Cr content of the Zn--Cr alloy plating, the Cr plating deposition rate and the chromate coating deposition rate was selected.
A laminated metal plate, one of which is outside the scope of the present invention, was produced in the same manner as in Example 1. Then, the same test as in Example 1 is performed,
The end face corrosion resistance and adhesion were evaluated. The results are shown in Table 5.

[0029]

[Table 5]

As is clear from the results shown in Tables 1 to 5,
In Comparative Example 1, both the end face corrosion resistance and the adhesiveness could not be satisfied, whereas the Z content of the Cr content of 1 to 70 wt% was present on at least the surface of the metal plate layer that is to be joined to the resin layer.
Examples 1 to 4 in which n-Cr alloy plating was applied at a deposition amount of 0.5 to 100 g / m ² and chromate treatment was performed on the alloy plating at a deposition amount of 5 to 150 mg / m ^2.
Has achieved a high level of end face corrosion resistance and adhesion.

[0031]

As described above, according to the present invention, it is possible to obtain a laminated metal plate having excellent end face corrosion resistance and adhesion.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a laminated metal plate of the present invention.

[Explanation of symbols]

 1 Base Metal Plate 2 Zn-Cr Alloy Plating Layer 3 Chromate Layer 4 Resin Layer

Claims (1)

[Claims] 1. A laminated metal plate comprising a resin layer and a metal plate layer sandwiching the resin layer from both sides, wherein a Cr content of 1 to 70 wt% is present on at least the surface of each metal plate layer to be joined to the resin layer. % Zn-Cr alloy plating is applied at an adhesion amount of 0.5 to 100 g / m ² , and chromate treatment is applied to a surface of the alloy plating that is in contact with the resin layer at an adhesion amount of 5 to 150 mg / m ^2. A laminated metal plate excellent in end face corrosion resistance and adhesion, which is characterized in that