JPH07314602A - Resin-coated aluminum plate with excellent press formability for molded parts of electric and electronic devices - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a resin-coated aluminum plate for molded parts of electric and electronic devices, which is excellent in moldability. [Structure] The surface roughness of aluminum or an aluminum alloy is adjusted to 0.8 μm or less for Ra and 5 μm or less for Rz, and powdery with respect to 100 parts by weight of an organic resin through a surface chemical conversion treatment layer on the surface. A resin-coated aluminum plate for electric and electronic equipment molded parts, which is provided with an organic resin layer having a dry film thickness of 5 μm or less by an organic resin composition containing 1 to 30 parts by weight of a lubricant and which has excellent press workability.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin-coated aluminum or aluminum alloy plate which is excellent in press workability in the manufacturing process of molded parts for electric and electronic devices. In the present specification, the aluminum or aluminum alloy plate is simply referred to as an aluminum plate hereinafter.

[0002]

2. Description of the Related Art Aluminum plates are used for home appliances, office automation equipment,
It is widely used in various fields such as containers, and is often pressed in the manufacturing process. The types of press working include deep drawing, bulging, stretch flange forming, bending, and the like, and it is common to apply lubricating oil for working. However, when the press working is performed using the lubricating oil, there are the following problems. That is, (1) the lubricating oil is often applied by spraying, which causes the lubricating oil to scatter around and deteriorates the working environment. (2) A cleaning process is required to remove the lubricating oil after pressing. However, there is a problem that organic solvents such as CFCs and trichloroethane used here are about to be abolished due to global environmental problems such as ozone layer depletion. Therefore, it is desired to develop an aluminum plate that can be pressed without a lubricating oil and can be omitted from the washing process.
A material in which an aluminum surface is coated with an organic resin as disclosed in 9792 has been developed. According to such a conventional resin-coated aluminum plate, press working without lubrication became possible. However, since this resin-coated aluminum plate has a limit in workability, it cannot sufficiently cope with various press workings as described above, and the molding using this product has low productivity. In addition, it is satisfactory if there is little processing deformation, but there is a problem that processing defects may occur when processing deformation is large, or in processing with severe processing conditions such as drawing processing and ironing processing. Was not.

[0003]

As described above, further improvement in press workability is desired so that the resin-coated aluminum plate can be applied to products subjected to high workability. Therefore, an object of the present invention is to provide a resin-coated aluminum plate for electric and electronic equipment molded parts, which is excellent in moldability and which overcomes the above-mentioned problems of the conventional ones. A further object of the present invention is to provide a resin-coated aluminum plate for electric and electronic equipment molded parts, which has excellent press workability and can enhance the productivity of molding.

[0004]

Means for Solving the Problems As a result of intensive studies in view of the above circumstances, the present inventors regulated the surface roughness of an aluminum material to a certain value or less, and contained a lubricant having a specific composition therein. It has been found that the one having the organic resin layer formed is particularly excellent in press workability and is suitable for molded parts of electric and electronic devices, and based on this finding, the present invention has been accomplished. That is, in the present invention, (1) the surface roughness of the aluminum plate is such that Ra is 0.8 μm or less and Rz is 5 μm.
1 to 30 parts by weight of powdered lubricant with respect to 100 parts by weight of the organic resin through the surface chemical conversion treatment layer.
Depending on the organic resin composition contained by weight, the dry film thickness is 5
An organic resin layer having a thickness of not more than μm is provided, and the powdery lubricant has an average particle size of 10 μm or less, and the average particle size is 1 to 10 times the dry film thickness. Resin-coated aluminum plate for electric / electronic device molded parts having excellent properties, and (2) the resin-coated aluminum plate for electric / electronic device molded parts according to (1), wherein the powdery lubricant is wax and / or fluororesin. Is provided.

[0005]

Next, the present invention will be described in detail. In the resin-coated aluminum plate of the present invention, the range of the surface roughness of the aluminum base plate is set to 0.8 μm or less in Ra and 5 μm or less in Rz because the press workability is remarkably deteriorated when these values are exceeded. is there. Conventionally, it has been considered that it is preferable to increase the surface roughness as much as possible in press working using a resin-coated aluminum plate, and such surface roughness is Ra1 to 2 μm and Rz6 to 7 μm.
The surface roughness of such a plate was manufactured by performing shot blasting on a roll in advance and rolling with this roll. As in the present invention, the surface roughness Ra is 0.8 μm,
It is unexpected from the above circumstances that if the Rz is 5 μm or less, the workability is significantly improved if the thickness is made smaller than this. Further, the correlation between the surface roughness of the resin-coated aluminum plate and the workability with the resin has not been known so far. The ranges of the surface roughnesses Ra and Rz of the aluminum base plate of the present invention are as described above, but preferably R
a is 0.1 to 0.6 μm and Rz is 0.5 to 3 μm, and more preferably Ra is 0.1 to 0.4 μm and R
z is 0.5 to 2 μm. In the present invention, both surface roughness Ra and Rz must satisfy the above conditions. If either Ra or Rz exceeds the above range, the desired moldability cannot be achieved.
The surface roughness specified in the present invention is preferably ensured immediately before the resin coating process. This corresponds to the roughness after the base chemical conversion treatment, but since the thickness of the base chemical conversion coating layer is generally about 5 to 50 nm, there is almost no change in the roughness due to the base chemical conversion treatment. Therefore, there is no problem as long as this surface roughness is secured in the state of the bare sheet after rolling or in the degreasing treatment step which is a step prior to the base chemical conversion treatment.

As the undercoat chemical treatment, coating type, reaction type, electrolytic type and other chromate treatments and non-chromate treatments are generally used, and these can be used. It is not particularly limited. As the resin of the organic resin layer to be coated, epoxy resin, alkyd resin, acrylic resin, urethane resin,
Phenolic resins, melamine resins, polyvinyl butyral resins, polyester resins and the like are preferably used alone or as a mixture or copolymer of two or more kinds. Of the above resins, epoxy, acrylic and urethane are preferable. The dry film thickness of these resin layers is limited to 5 μm or less because if it exceeds 5 μm, a part of the film is likely to be peeled off during processing and the workability is deteriorated. The dry film thickness of the resin layer is preferably 0.
It is in the range of 1 to 3 μm, more preferably 0.5 to 3 μm. On the other hand, if it is less than 0.05 μm, it becomes difficult to coat the aluminum surface uniformly, and the effect of the resin for improving the workability may be reduced.

As the powdery lubricant, it is preferable to use wax, fluororesin or a mixture thereof.
As wax, natural wax, paraffin wax,
Examples thereof include polyolefin wax (for example, polyethylene wax and polypropylene wax) and oxidized or modified polyolefin wax (for example, oxidized or modified polyethylene wax and oxidized or modified polypropylene wax). Examples of the fluororesin include polytetrafluoroethylene resin, polyvinyl fluoride resin, and polyvinylidene fluoride resin. The average particle size of these lubricants is 10 μm or less, preferably 8 μm or less, and it is preferable to use them in the range of 1 to 10 times the dry film thickness, and the average particle size of the lubricant is less than the dry film thickness. In contrast, the lubricity is insufficient, and conversely, if it is too large, the lubricant is likely to fall off during processing. A more preferable range is 1.5 to 5 times the dry film thickness. Also, the powdered lubricant is organic resin 1
1 to 30 parts by weight, preferably 5 to 2 with respect to 00 parts by weight
The amount is 0 parts by weight, more preferably 10 to 20 parts by weight. Addition of less than 1 part by weight of the lubricant to 100 parts by weight of the organic resin is not sufficient for improving the lubricity, and addition of more than 30 parts by weight may reduce the cohesive force of the organic resin. There is no particular limitation on the type and standard of the aluminum plate used in the present invention. It can be applied to any aluminum alloy type other than pure aluminum type. In the present invention, the electric and electronic device molded parts mean various electric and electronic device parts such as cases, structural members, floppy disks and the like for home electric appliances and OA devices, and there is no particular limitation on the shape and type. Further, the resin-coated aluminum plate of the present invention can be applied to a container for cosmetics other than parts for electric and electronic devices and a fin material for a heat exchanger. The details of the reason why the resin-coated aluminum plate for electric and electronic equipment molded parts of the present invention exhibits excellent moldability have not yet been clarified. If a conventional lubricant or resin was used, if the surface smoothness was high, the oil or resin would escape from the interface between the material and the mold during processing, and metal contact would easily occur, resulting in poor workability. I will end up. Therefore, as described above, a structure having a large surface roughness and capable of holding oil or resin on the surface has been used. On the other hand, the surface roughness is small as in the present invention, and moreover, it should be set to a certain value or less. It was unexpected that the workability could be significantly improved by. It is considered that this is because the coating of the organic resin acts effectively under the condition of the surface roughness described above, and the pressing force can be applied to the entire surface of the material while holding the resin coating film.

[0008]

EXAMPLES The present invention will be described in detail below based on examples. Example 1 Using JIS A1100, samples having a plate thickness of 1 mm adjusted to various surface roughness by changing the roll roughness during rolling were prepared, and then subjected to phosphoric acid chromate treatment as a base chemical conversion treatment ( The adhesion amount is 2 in terms of metallic Cr in the film.
0 mg / m ² ), average particle size of about 2 μm as powdered lubricant
1 of 100 parts by weight of polyolefin wax
0.5 μm dry film thickness of epoxy resin containing 5 parts by weight
Was applied. These samples were subjected to a cylindrical deep drawing test under the conditions of a punch diameter of 40 mmφ, a drawing ratio of 2.0 and a wrinkle holding force of 0.1 kgf / mm ² using the mold shown in FIG. ), The one in which breakage occurred was regarded as a defect (x). In FIG. 1, S is a sample, 1 is a punch, 2 is a drawing die, and 3 is a wrinkle holding die. The results are shown in Table 1.

[0009]

[Table 1]

As is apparent from Table 1, the experimental No. 1 whose surface roughness is not within the range specified by the present invention. 7, No. 8, No.
9 and the conventional example No. In No. 10, breakage occurred without drawing through. On the other hand, the experiment No. of the present invention. In Nos. 1 to 6, good moldability was exhibited without such defects. This experiment No. Those of 1 to 6 are suitable for drawing.

Example 2 No. 1 used in Example 1 was used. 4 base plate (Ra: 0.57μ
m, Rz: 2.44 μm), a phosphoric acid chromate treatment (adhesion amount is 20 mg / m ^{2 in} terms of metal Cr in the coating) is performed as a base chemical conversion treatment, and then a resin film thickness as shown in Table 2 is obtained. Samples with different lubricant particle sizes and lubricant ratios were prepared. These were subjected to a molding test under the same conditions as in Example 1,
The press workability was evaluated. The evaluation was carried out by visually observing the difference between omission (o) / fracture (x) and observing the appearance after processing, as in Example 1. The results are shown in Table 2.

[0012]

[Table 2]

As is clear from Table 2, the experiment No. 1 in which the resin film was too thick No. 11 or the lubricant particle size is too large. 1
In No. 2, the press workability is good, but it can be seen that the resin peels off during processing and uneven appearance occurs. In addition, the lubricant particle size is too small for the resin film thickness. 1
In No. 4, the effect of improving the workability was not recognized, and the ratio of the lubricant was too large. In No. 13, the effect of improving the workability is not recognized, and uneven appearance is also generated. On the other hand, in Experiment No. Each of the resin-coated aluminum sheets of the present invention shown in 1 to 10 has a good press workability and a good appearance after the work. This experiment No. The resin-coated aluminum plates 1 to 10 are suitable for drawing.

[0014]

INDUSTRIAL APPLICABILITY As described above, the resin-coated aluminum sheet for molded parts of electric and electronic devices of the present invention is excellent in press workability, and is also excellent in high-process forming with many process deformations such as drawing process. (It is possible to perform strict working conditions, for example, drawing work that exceeds a drawing ratio of 2.0). Further, this resin-coated aluminum plate has a relatively low manufacturing cost, and there is no need to degrease the resin coating after the molding process. If this is used, the productivity of the molding process can be increased and it can be used industrially. It is suitable. Further, there is no problem such as deterioration of working environment such as in the case of using lubricating oil and occurrence of various environmental problems due to implementation of cleaning process. The present invention has a remarkable effect industrially.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a mold used in a deep drawing test performed in Example 1 of the present invention.

[Explanation of symbols]

 S Sample 1 Punch 2 Drawing die 3 Wrinkle holding die

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Takahiro Sato 2-6-1, Marunouchi, Chiyoda-ku, Tokyo Furukawa Electric Co., Ltd. (72) Inventor Motohiro Namba 2--6, Marunouchi, Chiyoda-ku, Tokyo No. 1 Furukawa Electric Co., Ltd. (72) Inventor Koji Uesugi 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Kawasaki Steel Corporation Technical Research Headquarters (72) Inventor Naoki Nishiyama Kawasaki-cho, Chiba-shi, Chiba-shi No. 1 Kawasaki Steel Co., Ltd. Technical Research Division (72) Inventor Koichi Hashiguchi No. 1 Kawasaki-cho, Chuo-ku, Chiba City, Chiba Prefecture Kawasaki Steel Co., Ltd. Technical Research Division (72) Inventor Yoshihiro Matsumoto Chuo-ku, Chiba City Kawasaki Town No. 1 Kawasaki Steel Corporation Technical Research Division

Claims (2)

[Claims] 1. A surface roughness of an aluminum plate is adjusted so that Ra is 0.8 μm or less and Rz is 5 μm or less, and powdery with respect to 100 parts by weight of an organic resin through a surface chemical conversion treatment layer on the surface. An organic resin layer having a dry film thickness of 5 μm or less is provided with an organic resin composition containing 1 to 30 parts by weight of a lubricant, and the powdery lubricant has an average particle size of 10 μm.
m or less, and the average particle size is 1 to 10 of the dry film thickness.
Electricity with excellent press workability, which is characterized by double
Resin coated aluminum plate for molded parts of electronic devices. 2. The resin-coated aluminum plate for electric / electronic device molding parts having excellent press moldability according to claim 1, wherein the powdery lubricant is wax and / or fluororesin.