JPH1177896A - Laminated sheet for draw-ironing work and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the generation of the break and crack of a resin layer formed on a surface even when ironing work is applied after draw work and to also prevent the generation of ply separation between an aluminum panel and the resin layer. SOLUTION: A laminated sheet for draw-ironing work is produced by arranging a resin layer composed of a polyamide resin on at least one surface of an aluminum or aluminum alloy panel at first and subsequently heating the resin layer to melt the same and thereafter cooling the molten resin layer at a cooling speed of 50( deg.C/sec) or more to form the resin layer in which spherules are not substantially present on the surface of the panel.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a draw ironing laminate used for an electrolytic capacitor cap or the like for accommodating an electrolytic capacitor element and a method of manufacturing the same, and particularly to a case where ironing is performed after drawing. The present invention also relates to a drawn ironing laminate having excellent interlayer adhesion, which can prevent the occurrence of delamination or cracks in the resin layer, and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, laminated plates having various resin films laminated on the surface thereof have been manufactured for the purpose of enhancing the corrosion resistance, electrical insulation, aesthetics, etc. of aluminum or aluminum alloy plates. Such laminates are used in various fields. Hereinafter, the aluminum or aluminum alloy plate is collectively referred to as an aluminum plate.

Incidentally, a cap for an electrolytic capacitor is obtained, for example, by drawing an aluminum plate into a circular shape with a bottom. Then, the capacitor element impregnated with the electrolytic solution is accommodated in the cap for the capacitor, and the opening of the cap is sealed with rubber or the like. By being covered with a heat-shrinkable tube made of, an electrolytic capacitor component is manufactured.

In recent years, with the miniaturization of electronic components, the miniaturization of electrolytic capacitor components has been required, and the development of chip-type electrolytic capacitor components that do not require lead wires for surface mounting is in progress.

However, when the cap for an electrolytic capacitor is miniaturized with the miniaturization of components, it becomes difficult to cover the cap with a heat-shrinkable tube. Further, when the cap is miniaturized, the capacity of the cap is reduced, so that the stored capacitor element comes into contact with the inner surface of the cap, which causes a problem that insulation is impaired.

Therefore, it has been proposed to use a laminated plate obtained by coating the surface of an aluminum plate with an insulating resin layer as a material for a cap for an electrolytic capacitor. In particular, a laminated plate obtained by laminating a polyamide resin film having excellent heat resistance and moldability on an aluminum plate is suitable as a material for a cap for an electrolytic capacitor.

[0007] As a method of coating the surface of an aluminum plate with an insulating resin layer, a method of coating a molten resin on the surface of the aluminum plate or a method of laminating a resin film on the surface of the aluminum plate are known. In addition, it is known that a resin made of an epoxy-based, vinyl chloride-based, polyester-based, or the like is used as a material of the insulating resin layer. Furthermore, there is disclosed a laminate in which a polyamide resin layer is laminated on at least one surface of an aluminum plate, wherein the maximum diameter of spherulites in the resin layer is regulated to 10 μm or less (Japanese Unexamined Patent Publication No. Hei 8 (1996)). 1857). This aluminum laminate improves the interlayer adhesion between the aluminum plate and the resin layer by regulating the maximum diameter of the spherulites present in the polyamide resin layer.

[0008] Such a conventional painted plate or laminated plate (laminate) has excellent adhesion between the aluminum plate and the resin layer. Also, even if this plate material is subjected to drawing for use as a material for a cap for an electrolytic capacitor, cracks and the like occur in the resin layer because the adhesion between the aluminum plate and the film after drawing is good. Can be suppressed.

[0009]

However, if the conventional painted plate or laminated plate is further ironed after drawing, the resin layer may be broken or cracked. In addition, there is also a problem that delamination or the like is easily caused by the ironing process.

The present invention has been made in view of such a problem, and even if ironing or the like is performed after drawing, it is possible to prevent the resin layer from breaking or cracking, and to prevent the aluminum layer from being damaged. An object of the present invention is to provide a laminate plate for drawing and ironing which can prevent the occurrence of delamination between a resin layer and a resin layer, and a method for manufacturing the same.

[0011]

A laminate plate for drawing and ironing according to the present invention comprises an aluminum or aluminum alloy plate and a polyamide resin layer formed on at least one surface of the aluminum or aluminum alloy plate. Wherein the polyamide resin layer is substantially free of spherulites.

Preferably, a chromate film is provided between the aluminum or aluminum alloy plate and the polyamide resin layer.

[0013] In the method of manufacturing a laminated sheet for drawing and ironing according to the present invention, a step of arranging a resin layer made of a polyamide resin on at least one surface of an aluminum or aluminum alloy sheet, and a step of melting the resin layer And cooling the molten resin at a cooling rate of 50 (° C./second) or more to adhere a resin layer substantially free of spherulites onto the surface. .

[0014] The method of manufacturing a laminate for drawing and ironing according to the present invention preferably includes a step of forming a chromate film on the surface before the step of disposing the resin layer.

In the present invention, since substantially no spherulite exists in the polyamide resin layer, even if ironing is performed, the resin layer does not break or crack, and delamination can be prevented.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION A laminate plate for drawing and ironing according to the present invention is obtained by forming a polyamide resin layer on at least one surface of an aluminum plate. The present inventors form a resin layer substantially free of spherulites in order to prevent cracks and the like from occurring in the resin layer when performing ironing in addition to drawing on the laminate plate. Was found to be necessary. This is because if spherulites are present in the resin layer, the resin layer is likely to be broken or delaminated when the ironing process is performed in addition to the drawing process on the laminate plate. Therefore,
In the present invention, it is assumed that spherulites are not substantially present in the resin layer formed on the surface of the aluminum plate. The presence or absence of the spherulites can be confirmed by observing the surface of the resin layer with a polarizing microscope or a scanning microscope.

Further, since the polyamide resin has excellent heat resistance and moldability, a polyamide resin layer is formed on at least one surface of an aluminum plate, and then formed into a product by drawing and ironing. In this case, good moldability can be obtained, and a product having excellent heat resistance can be obtained.

Further, in the present invention, between the aluminum plate and the resin layer, a phosphoric acid chromate treated film, a chromate chromate treated film, a film composed of an organic resin and Cr, or a chemical containing Zr or Ti is used. A treatment film may be formed. Further, the surface of the aluminum plate on which the resin layer is formed may be subjected to a treatment by electrolytic etching. As described above, when the film is formed between the aluminum plate and the resin layer or when the surface of the aluminum plate is subjected to the etching treatment, the adhesion of the resin layer can be improved.

A laminate having a polyamide resin layer substantially free of spherulites can be manufactured, for example, as follows. First, an adhesive is applied to an aluminum plate and dried. Next, a polyamide resin film is attached to the surface of the aluminum plate. Thereafter, after the film is melted by heating, the film is cooled at a predetermined cooling rate, so that the resin layer is applied to the surface of the aluminum plate. Alternatively, a method in which a polyamide-based resin film is directly adhered to the surface of an aluminum plate, and then the film is melted by heating, and then cooled at a predetermined cooling rate, whereby a resin layer is applied to the surface of the aluminum plate. is there.

In the present invention, no matter which method is used, it is necessary to appropriately regulate the cooling rate after the film is melted. This cooling rate is 5
When it is less than 0 (° C./sec), spherulites are formed in the resin layer. As a result, when the obtained laminated plate is subjected to ironing in addition to drawing, the resin layer may be broken and cracked, or delamination may occur between the aluminum plate and the resin layer. Therefore, in the present invention, the molten resin is cooled at a cooling rate of 50 (° C./second) or more.

As a cooling method of the molten resin, there are a water cooling method and an air cooling method, and any cooling method may be used.
Since the polyamide resin has high water absorption, it is preferable to use an air cooling method.

The aluminum plate used in the present invention is not particularly limited, but it is preferable to use a plate made of pure aluminum or an alloy of aluminum and manganese. When a laminate plate is manufactured as a material for the cap for an electrolytic capacitor, the thickness of the aluminum plate is preferably 0.25 to 0.5 mm. In the present invention, nylon 6, nylon 66, a copolymer thereof, or the like can be used as a material for the polyamide resin layer.

[0023]

EXAMPLES The results of the production of a laminate for drawing and ironing by the production method according to the examples of the present invention will be specifically described in comparison with the results of comparative examples. First, one surface of a JIS 1100 aluminum plate having a thickness of 0.3 mm was subjected to a phosphoric acid chromate treatment. Next, a polyurethane-based resin melted as an adhesive was applied to the surface of the formed chromate film, and after drying, a nylon 6 film having a thickness of 15 μm was disposed on the surface. The melting point of this nylon 6 is 220 ° C., and the crystallization temperature is 45 ° C.

Next, after melting the nylon 6 film at a temperature of 240 ° C., the film is cooled at various cooling temperatures using a cooler, and a resin layer made of the nylon 6 film is adhered to the surface of the aluminum plate. Thereby, a laminated board was manufactured. Thereafter, the presence or absence of spherulites on the surface of the resin layer was evaluated. However, the presence or absence of spherulites was determined by taking a photograph of the resin layer surface at a magnification of 6000 times using a differential interference microscope and 1600 using a scanning electron microscope.
The resin layer surface was photographed at a double magnification, and the photographs were evaluated by observing the photographs. Therefore, when no spherulite was observed on these two types of photographs, it was evaluated that there was no spherulite.

Thereafter, the obtained laminated plate is drawn with the surface on which the resin layer is formed outside, and then drawn at an ironing rate of 30% to produce a cap for an electrolytic capacitor. Was evaluated for draw ironability. The outer surface (resin layer) of the obtained electrolytic capacitor cap is dyed blue with an acidic dye to determine whether or not delamination has occurred between the aluminum plate and the resin layer, and whether the resin layer has been broken or ironed. The occurrence of cracks was evaluated by observing with a stereoscopic microscope. Table 1 below shows the cooling rates and evaluation results during the production of the laminate.
In addition, the comparative example No. The columns for the presence or absence of spherulites 2 and 3 also show the average diameter of spherulites observed in a micrograph taken at a magnification of 1600 times with a differential interference microscope.

[0026]

[Table 1]

As shown in Table 1 above, Example No. 1
Since the cooling rate of the molten resin was 50 (° C./second) or more, no spherulite was formed in the resin layer. Therefore, even if the obtained laminated plate was subjected to drawing and ironing, it was possible to prevent the resin layer from breaking, cracking, etc., and from delamination between the aluminum plate and the resin layer.

On the other hand, in Comparative Example No. In Nos. 2 and 3, since the cooling rate of the molten resin was less than 50 ° C., spherulites were formed in the resin layer, and delamination occurred when the obtained laminated plate was subjected to drawing and ironing.

[0029]

As described in detail above, according to the present invention,
Since a polyamide resin layer substantially free of spherulites is formed on the surface of the aluminum or aluminum alloy plate,
When the obtained laminated plate is subjected to drawing and ironing, it is possible to prevent the resin layer from breaking and cracking, and to cause delamination between the aluminum or aluminum alloy plate and the resin layer. Can be prevented. Further, according to the method of the present invention, when the polyamide resin layer is formed on the surface of the aluminum or aluminum alloy plate, the cooling rate of the molten resin is appropriately regulated, so that the polyamide having substantially no spherulite is present. A system resin layer can be formed, whereby the occurrence of breakage and cracks of the resin layer and the occurrence of delamination between the aluminum or aluminum alloy plate and the resin layer can be prevented.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masanobu Fukui 15 Kinuigaoka, Moka-shi, Tochigi Pref. Inside Kobe Steel Moka Works (72) Inventor Shigetsugu Konagaya 2-1-1 Katata, Otsu-shi, Shiga No. Within Toyobo Co., Ltd. Research Institute (72) Inventor Akito Hamano 2-1-1 Katata, Otsu-shi, Shiga Prefecture Within Toyobo Co., Ltd. Research Center (72) Inventor Shinji Suzuki 2-chome Katata, Otsu-shi, Shiga Prefecture No. 1 Toyobo Co., Ltd. Research Laboratory

Claims (4)

[Claims] 1. A laminated plate having an aluminum or aluminum alloy plate and a polyamide resin layer formed on at least one surface of the aluminum or aluminum alloy plate, wherein spherulites are contained in the polyamide resin layer. A laminate for drawing and ironing, which is substantially absent. 2. The drawing and ironing laminate plate according to claim 1, further comprising a chromate film between the aluminum or aluminum alloy plate and the polyamide resin layer. 3. A step of disposing a resin layer made of a polyamide resin on at least one surface of an aluminum or aluminum alloy plate, and a step of melting the resin layer;
Cooling the molten resin at a cooling rate of 50 (° C./second) or more, thereby depositing a resin layer substantially free of spherulites on the surface. A method for producing a laminated board for processing. 4. The method according to claim 3, further comprising a step of forming a chromate film on the surface before the step of disposing the resin layer.