JP3510166B2 - Multi-layer laminated metal sheet and method for producing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a multi-layer laminated metal plate having a resin layer between two metal plates and a method for manufacturing the same.
It INDUSTRIAL APPLICABILITY The multi-layer laminated metal plate of the present invention can be used for building materials, home electric appliances, bathtubs, automobile outer plates, and the like.

[0002]

2. Description of the Related Art From the viewpoint of saving global resources and reducing air pollution, the weight of vehicle bodies has been reduced in order to improve the fuel efficiency of automobiles. For example, in engines and the like, conversion from cast iron to aluminum alloy is being carried out. Further, in various automobile parts, conversion from metal to plastic or ceramics is often performed.

In addition, a composite material in which a metal and a resin are laminated has been developed in order to reduce the weight while taking advantage of the advantage of the metal. For example, Japanese Patent Application Laid-Open No. 2-241734 proposes a metal-resin bonding plate in which a hollow resin plate formed by extrusion molding and a metal plate are bonded with an adhesive. According to such a composite material, strength and heat resistance can be secured by the metal plate, and the weight can be reduced by the hollow resin plate.

Incidentally, a metal-resin joint plate in which a solid resin plate and two metal plates are laminated in a sandwich form, or a metal-resin joint in which a foam layer is formed by foaming a foam resin between the two metal plates. Plates are also known. Even with these metal-resin bonded plates, the resin plate or the foam layer can reduce the weight.

[0005]

Although a steel plate having a thickness of about 1 mm is used as an outer plate of an automobile, if it is made thinner than this, problems will occur in strength, so it is necessary to consider other means for reducing the weight. is there. Therefore, it is possible to use the metal-resin joint plate as described above also in the automobile outer plate. However, in the above-mentioned metal-resin joint plate, it is difficult to adopt these metal-resin joint plates for automobile outer plates because it is inferior to steel plates in terms of formability and cost.

[0006] For example, when a metal-resin joint plate in which a hollow or solid resin plate is joined between two steel plates is press-formed into a predetermined shape, the outer and inner steel plates are deformed due to the thickness of the resin layer. There is a difference in quantity. Therefore, there is a problem that internal stress is generated in the resin layer due to the difference, and the steel plate warps due to the internal stress after forming. Therefore, it is difficult to perform molding with high accuracy using such a metal-resin joint plate, and it is difficult to adopt it for an automobile outer plate.

The above problems occur when the joint strength between the resin layer and the steel sheet is large, and when the joint strength is small, the above problems can be avoided. However, if the bonding strength is low, there is a problem that delamination occurs between the resin layer and the steel sheet.

Further, in the method disclosed in Japanese Patent Application Laid-Open No. 2-241734, an extrusion step and a joining step are required to manufacture the metal-resin joint plate, and the number of steps is large, so that the obtained metal-resin joint plate is expensive. Becomes In addition, the method of forming the foam layer also increases the cost because the foaming agent is used.

The present invention has been made in view of the above circumstances, and a first object thereof is to provide a light-weight and low-cost multi-layer laminated metal plate.

A second object of the present invention is to provide a metal-resin bonded plate which does not cause warpage or delamination of the metal plate after molding.

[0011]

The features of the multi-layer laminated metal sheet of the present invention for solving the above-mentioned problems are that the two metal sheets stacked together have a glass transition temperature or a melting point or higher between the two metal sheets. Formed by moving the two metal plates in the thickness direction away from each other through the heated molten resin to increase the apparent volume of the molten resin and solidifying the molten resin in that state. And a hollow resin layer welded to each metal plate.

Further, the feature of the method for producing a multi-layer laminated metal plate of the present invention is that a molten resin having a glass transition temperature or a melting point or higher is interposed between two stacked metal plates to form two metal plates. The apparent volume of the molten resin is increased by moving them away from each other in the thickness direction, and in that state the molten resin is solidified to form a hollow resin layer and the hollow resin layer is welded to two metal plates respectively. To do.

[0013]

[0014]

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION In the method for producing a multi-layer laminated metal sheet according to the present invention, a molten resin heated to a glass transition temperature or a melting point or higher is interposed between two superposed metal sheets.
The hollow resin layer is formed by moving the metal plates in the thickness direction in directions away from each other to increase the apparent volume of the molten resin and solidifying the molten resin in this state. That is, by moving the two metal plates in a direction away from each other in the thickness direction to increase the apparent volume of the molten resin, air penetrates into the molten resin to form bubbles. In some cases, vacuum bubbles are also formed. This reduces the apparent specific gravity of the resin layer,
A lightweight hollow resin layer is formed.

Further, since the hollow resin layer is welded and joined to two metal plates respectively, by selecting a resin having a high welding strength to the metal plates, a multi-layer laminated metal plate in which delamination does not occur is obtained. can do. Further, since the extrusion molding process and the bonding process using an adhesive are unnecessary, the multilayer metal plate can be manufactured at low cost.

In the multi-layer laminated metal plate of the present invention, the hollow resin layer can maintain a predetermined thickness due to the air bubbles in the hollow resin layer, and the same forming process as that for a single metal plate can be performed. Further, due to the presence of the hollow resin layer, it is lightweight, has excellent heat insulating properties and shock absorbing properties, and maintains high rigidity due to the exposed metal plate. And flexibility is also given by the structural web formed in the hollow resin layer,
Bending or twisting force is comparable to metal plates of the same thickness.

[0018]

[0019]

In the method for producing a multi-layer laminated metal sheet according to the present invention
Then, in order to interpose the molten resin heated to the glass transition temperature or the melting point or higher between the two metal plates, the molten resin may be injected between the two metal plates, or the molten resin may be melted onto one metal plate. The resin may be supplied and another metal plate may be stacked and compressed. Further, it is also possible to heat and melt a laminated metal plate in which a thermoplastic resin is laminated in advance between two metal plates in a solid sandwich form. In this case, a known metal-resin bonding plate can be used.

Further, the two metal plates can be moved in the thickness direction in the direction away from each other by, for example, magnetic attraction or vacuum attraction. The moving distance between the two metal plates is
105 to 50 with the thickness of the solid resin before melting as 100%
It is desirable to set it in the range of 0%. If it is less than 105%, the amount of bubbles formed is too small to make it difficult to reduce the weight, and the resulting multi-layer laminated metal sheet lacks flexibility.
If it exceeds 0%, the strength of the multi-layer laminated metal sheet is insufficient.

The material of the metal plate is not particularly limited, such as iron, steel, aluminum or aluminum alloy, and copper, but when used as an automobile outer plate, a steel plate is used.

As the resin constituting the hollow resin layer, both thermosetting resin and thermoplastic resin can be used. For example, a liquid resin such as a mixture of an epoxy resin and a polyamide resin is placed between two metal plates, and the two metal plates are moved in a direction away from each other in the thickness direction and then reacted and cured to form a hollow resin layer. be able to. However, in the case of a thermosetting resin, the reaction may take time and the number of steps may be large. The multilayer laminated metal plate which is produced, since heating and melting of the hollow resin layer it is difficult, to mold thereafter
It is difficult. Therefore, a thermoplastic resin is preferable as the resin forming the hollow resin layer.

In addition , the melt viscosity is relatively high (preferably ASTM D123 230 ° C.) in order to prevent the hollow resin layer from fluidizing and changing the plate thickness during molding.
It is desirable to use a thermoplastic resin having a MI of 2.16 kg of 1 to 10). Examples of such thermoplastic resins include PP, PA, PS, PBT, PPE, PPO, and AB.
Examples include S, AES and alloys thereof. Also, if necessary, talc, glass fiber,
It may contain a filler such as an elastomer.

Further, as the thermoplastic resin, those which are welded to the metal plate with great strength are desirable. For this purpose, a known technique such as maleation of the thermoplastic resin described above can be used. Further, it is also preferable to use a multilayer resin in which a joining resin layer made of a thermoplastic resin having a high welding strength with a metal plate such as polyimide is formed on the front and back surfaces of a thermoplastic resin having a high melt viscosity. It is also possible to apply polyimide, epoxy, or the like to the surface of the metal plate in advance to increase the bonding strength with the metal plate. When a multi-layer resin is used, the thickness of the bonding resin layer such as polyimide is 0.005
It is desirable to set it to mm or less.

In order to heat the hollow resin layer above its glass transition temperature or melting point, it can be placed in an electric furnace or the like and heated by heat conduction through a metal plate. High frequency induction heating or the like may be used. The heating temperature may be equal to or higher than the glass transition temperature or melting point of the thermoplastic resin forming the hollow resin layer.

[0027]

EXAMPLES The present invention will be specifically described below with reference to examples.

(Embodiment 1) FIG. 1 shows a manufacturing method of this embodiment. First, two steel plates 1 having a thickness of 0.2 mm were stacked and preheated to 200 ° C. with a heater (FIG. 1a). Next, the distance between the two steel plates 1 was set to 0.3 mm, and the molten resin 2 made of an alloy of polypropylene and polyphenylene ether having an improved adhesiveness with the steel plates 1 at a temperature of 220 ° C.
Was extruded and pressed by a roll so that the whole had a uniform thickness (0.7 mm) (FIG. 1b).

Subsequently, while the molten resin 2 is above the melting point (160 ° C.) of polypropylene, the two steel plates 1 are moved in the thickness direction so as to be separated from each other by using the adsorption block 3 having a caterpillar structure. The distance between them is 0.6 mm
And At this time, air penetrates into the molten resin 2 through the opening of the end face to form the bubble 20 inside and the bubble 2
A structural web was formed between 0s (Fig. 1c).

In this state, the molten resin 2 was cooled and solidified to form the hollow resin layer 21 having the bubbles 20 welded to the two steel plates 1. The obtained multi-layer laminated steel sheet had strength equivalent to that of a steel sheet having a thickness of 1 mm against bending and twisting deformation, and was sufficiently usable as an automobile outer panel.

In the above embodiment, the adsorption block 3 having a caterpillar structure is used, but if a roll-shaped block is used, the hollow resin layer 21 can be continuously formed even with a long steel plate. is there.

By the way, it is known that a phenomenon as shown in FIG. 2 occurs when press working a laminated steel sheet having a sandwich structure having a resin layer. That is, when the laminated steel plate shown in FIG. 2a is bent in the mold as shown in FIG. 2b,
In the resin layer 200, a larger tensile stress acts on the outer steel plate 100 side than on the inner steel plate 101 side. Therefore, internal stress is generated in the resin layer 200, and the internal stress has different magnitudes in the thickness direction. Therefore, when the molded product is released from the mold, the internal stress of the resin layer 200 causes the steel plates 100 and 101 to warp as shown in FIG. 2C. This is generally called a seagull fold.

Therefore, in this example, the multi-layer laminated steel sheet obtained above was heated by using high frequency to make the hollow resin layer 21 in a molten state. Then, the product was placed in a press mold and press-molded as shown in FIG. 2, and after the hollow resin layer 2 was cooled and solidified, the molded product was released.

In the molding method of this embodiment, since the hollow resin layer 21 is molded in a molten state, even if there is a difference in the amount of deformation between the inner steel plate 1 and the outer steel plate 1, the hollow resin layer 21 is not affected. Therefore, no internal stress remains in the hollow resin layer 21 after solidification. Therefore, the steel sheet 1 was not warped after the forming, and the forming could be performed with high accuracy.

[0035]

That is, according to the multi-layer laminated metal plate of the present invention, it is lightweight while having the same rigidity as a metal plate of the same thickness. Therefore, if it is used as an outer panel of an automobile, the weight of the vehicle body can be reduced and fuel consumption can be reduced. According to the manufacturing method of the present invention, this multi-layer laminated metal plate can be easily manufactured with a small number of steps, and can be manufactured at low cost.

[0036]

[Brief description of drawings]

FIG. 1 is a process explanatory view showing a method for manufacturing a multi-layer laminated metal sheet according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a change in shape when a sandwiched laminated metal plate having a conventional resin layer is pressed.

[Explanation of symbols]

1: Metal plate 2: Molten resin 3: Adsorption block 20: Bubbles 21: Hollow resin layer

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yuji Tanaka 1-2-2 Yurakucho, Chiyoda-ku, Tokyo Asahi Kasei Kogyo Co., Ltd. (56) Reference JP-A-2-241734 (JP, A) JP-A-53 -144976 (JP, A) JP-A-50-10372 (JP, A) JP-A-63-13619 (JP, A) JP-B-44-15920 (JP, B1) (58) Fields investigated (Int.Cl . ⁷ , DB name) B32B 1/00-35/00

Claims (2)

(57) [Claims] 1. A stack of two metal plates and a molten resin heated to a glass transition temperature or a melting point or higher between the two metal plates is interposed between the two metal plates in the thickness direction. A hollow resin layer formed by solidifying the molten resin in that state by increasing the apparent volume of the molten resin by moving the resin in a direction away from each other, and a hollow resin layer welded to each of the two metal plates. And a multi-layer laminated metal plate. 2. A molten resin having a glass transition temperature or a melting point or more is interposed between two stacked metal plates,
The apparent volume of the molten resin is increased by moving the two metal plates away from each other in the thickness direction, and the molten resin is solidified in that state to form a hollow resin layer and the hollow resin. A method for producing a multi-layer laminated metal plate, which comprises depositing layers on two metal plates respectively.