JPH02111008A - Outer packaging for electronic components - Google Patents

Abstract

PURPOSE:To prevent an insulating property from being deteriorated when a capacitor element comes into contact with an inner face of an outer container by a method wherein a specific synthetic resin layer is formed at the inner face of the container. CONSTITUTION:A laminated sheet coated with a denatured polyolefin resin layer 2 formed by graft-copolymerizing unsaturated carboxylic acid or its derivative is formed on one face of an aluminum sheet 1 via a chemically formed layer 11 whose chromate coating amount is in a range of 5 to 150mg/m<2> or whose organic titanate coating amount is in a range of 3 to 200mg/m<2> while the laminate sheet is throttled in such a way that the denatured polyolefin resin layer is situated at the inner face. Thereby, even when a soldering operation by a reflow method is executed, a resin at the inner face of the outer container is not deteriorated by an influence of a temperature of a solder; an insulating property can be kept.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an outer container for electronic components in which specific synthetic tH 7 scraps are provided on the inner surface of a bottomed cylindrical container body made of an aluminum plate. The present invention relates to an outer packaging container for electronic components that has excellent glabella adhesiveness and electrolyte resistance and can be particularly suitably used for small-sized aluminum electrolytic capacitors and chip-type aluminum electrolytic capacitors.

(Prior Art and its Problems) A bottomed cylindrical container made by drawing an aluminum plate is usually used as an outer container for housing a capacitor element that constitutes an aluminum electrolytic capacitor.

In recent years, electronic components have become smaller, and aluminum electrolytic capacitors are also becoming smaller.
A chip-type aluminum electrolytic capacitor that eliminates lead wires (for chip-on-board) is being developed. Such small-sized aluminum electrolytic capacitors, especially chip-type electrolytic capacitors, have a problem in that because the outer container is small, the capacitor element contained therein comes into contact with the inner surface of the container, impairing insulation properties.

Therefore, the present inventors have proposed an outer container in which the inner surface of the container is coated with a polyamide resin as an insulating layer by drawing a laminate made of an aluminum plate with a polyamide resin layer on one side. However, when a chip-type electrolytic capacitor using such an outer container is soldered onto a printed circuit board by the reflow method, the polyamide on the inner surface of the outer container may be affected by the solder temperature, such as when the solder temperature is too high. Problems arose in that the resin layer absorbed the organic solvent in the electrolytic solution and foamed, or deteriorated due to hydrolysis.

(Means for Solving the Problems) The present invention has discovered that the above problems can be solved by providing a specific synthetic resin layer on the inner surface of the outer container, and the gist thereof is as follows: An unsaturated carboxylic acid or a derivative thereof is grafted onto one side of the aluminum plate 1 through a chemical conversion treatment layer 11 having a chromate film amount of 5 to 150 mg/ry1 or an organic titanate film and an olfactory value of 3 to 200 mg/ry1'. There is an outer container for electronic components formed by drawing a laminate plate coated with a copolymerized modified polyolefin resin R2 so that the modified polyolefin resin layer is on the inner surface side.

The present invention will be explained below with reference to the drawings.

FIG. 1 is a sectional view of the outer container of the present invention, FIG. 2 is a sectional view showing another embodiment, and FIG. 3 is an enlarged sectional view of a portion of FIG. 2. As shown in FIG. 1, the aluminum plate 1 used for the outer container is preferably one of the 1000 series by JISHOOOOI, with an aluminum content of 99% by weight or more, and a thickness of 0.2 to 0. A material with a diameter of about .4 mm can be suitably used. It is necessary to provide the aluminum plate with a chemical conversion treatment layer 11 having a chromate film amount or an organic titanate film amount within a specific range.

Various chemical conversion treatments and physical roughening methods such as sandblasting are known as means for improving the adhesion between the aluminum plate and the synthetic resin layer. It has been discovered that chemical conversion treatment using organic titanate treatment does not reduce interlayer adhesion even under harsh conditions such as during drawing, and chromate treatment methods include chromic anhydride, chromic anhydride,
The treatment can be easily carried out by spraying or dipping at a treatment temperature of about 40 to 50°C using a treatment liquid containing phosphoric acid, fluoride or a complex salt thereof, etc., and the amount of chromate film on the aluminum plate after treatment is 5. It needs to be in the range of ~150 mg/'+vf'. The amount of chromate film can be measured by measuring the amount of chromium on the treated surface by fluorescent X-ray analysis or the like and converting the amount.

The above chromate film amount is 5 rn g/rrf'
If it is less than 1 Om g, the effect of improving the adhesive force with the modified polyolefin resin or epoxy resin provided on the surface is small, and
/rt? If it exceeds ', there is a problem that the drawability of the laminate is poor.

In addition, as the organic titanate treatment method, an organic titanate [general formula T i (OR), i...R is an alkyl group, an allyl group, etc.] is diluted with a solvent such as hexane or isopropanol, and the It may be applied by a method such as a reverse roll method or a reverse roll method. The amount of this organic titanate film needs to be in the range of 3 mg/m2 to 300 mg/ryf'. The amount of organic titanate film can be measured by a method determined from the difference in weight before and after treatment.
g/rd, the modified polyolefin 1 provided on the surface
1! It has little effect on improving adhesion with pilgrims and epoxy resins,
If it exceeds 300 mg/nf, there is a problem that the drawability of the laminate is poor.

In the laminate used for the outer container of the present invention, the chemical conversion treatment layer 1
It is necessary to coat one side of the aluminum plate 1 with a modified polyolefin resin layer 4 obtained by craft copolymerizing an unsaturated carboxylic acid or a derivative thereof. Unsaturated carboxylic acids include acrylic acid, methacrylic acid, crotonic acid, maleic acid, etc., and derivatives thereof include maleic anhydride, itaconic anhydride, etc., and polyolefin resins include polyethylene, polypropylene, poly-1- Butene,
Examples include poly-4-methyl-1-bentene, ethylene-propylene copolymer, and the like. The thickness range of the modified polyolefin resin layer is 10 to 100 μm, preferably 10 to 100 μm.
A range of 50 μm is preferable from the viewpoint of drawing workability. The outer surface of the outer container formed by drawing the laminated plate provided with the modified polyolefin resin layer in this way can be covered with a conventional shrink tube as required.

However, if the outer container requires insulation on the top surface or printing on the top surface, it is necessary to coat the entire outer surface of the container with synthetic resin, but this is difficult to do with conventional outer surface coating using shrinkable tubes. Therefore, in that case, a laminate is used in which an epoxy resin layer 3 and a polyamide resin layer 4 are sequentially provided on the opposite side of the aluminum plate 1 through the above-mentioned chemical conversion treatment layer, and the laminate is drawn as shown in FIG. It can be processed into containers. The structure of the above laminate is shown in Figure 3, but
The epoxy resin used for the epoxy resin 1f13 of the laminate plate with resin laminated on both sides includes ordinary bisphenol type epoxy resins that do not use a curing agent, specifically bisphenol A monoglycidyl ether and bisphenol A diglycidyl ether. In addition, various epoxy resins such as bisphenol F type and resorcil type epoxy resins can be used.

The epoxy resin preferably has a molecular weight of about 300 to 3,000 and an epoxy equivalent of 150 to 3,200.

After coating, the above epoxy resin needs to be denatured by high-temperature baking.The heat treatment conditions for high-temperature baking vary depending on the type of resin used, but the aluminum plate after coating is heated to 250°C.
As mentioned above, it is preferable to bake at 350° C. or higher. If such high temperature baking is not performed, interlayer adhesion cannot be improved.

The polyamide resin layer 4 laminated on the high temperature baked epoxy resin layer includes 6-nylon, 6-row nylon, and 6-nylon.
Examples include a copolymer of nylon and 6-row nylon, and an aromatic polyamide resin made of metaxylene diamine and adipic acid. Polyamide resin layer The thickness range of the resin layer is preferably 10 to 100 μm, preferably 10 to 50 μm from the viewpoint of drawability and financial efficiency.

Various methods can be considered for laminating the modified polyolefin resin layer and the polyamide resin layer, but the melt lamination method is one in which films formed in separate processes are pressure-bonded onto an aluminum plate heated above the melting point of each film. This is preferable from the viewpoint of productivity and the like.

The laminate having the above structure is drawn using an ordinary drawing machine so that the modified polyolefin resin layer is on the inside, and is formed into a cylindrical container with a bottom.

Hereinafter, the present invention will be explained in detail with reference to Examples.

(Example) Example 1 Aluminum plate (A 1100 P-H2S thickness 0°3
mm) was subjected to chromate treatment using a treatment solution containing phosphoric acid, chromic anhydride, and fluoride at a treatment temperature of 40 to 50°C. By changing the concentration of the chromate treatment solution, surface-treated aluminum plates having the amount of chromate coating shown in Table 1 were obtained. After melt-laminating a film having a thickness of 20 μm as shown in Table 1 on one side of the treated surface, a sample of each laminate was obtained.

Using each sample obtained, "normal peel strength", "peel strength after deformation", "drawability", and "high temperature electrolyte resistance,"
The results of the evaluation are shown in Table 1.

Evaluation method: "Normal peel strength"... Cut out a 20 mm thick sample from each sample, put a notch in the aluminum layer, fold it back 1804 to create a peeling surface of the film, and then peel it at 50 mm/mi.
A 180° peel test was conducted at a peel rate of n, and the load at the time of peeling was measured.

"Peel strength after deformation"...each sample above at 35mm/m
After tensile deformation by 20% at a tensile speed of in, the sample was cut out and subjected to the same peeling test as above to measure the load at the time of peeling.

"Drawing workability"...Using each of the above laminates, drawing was performed in 7 stages using a lance progressive drawing machine, and 10IIIl
Create a cylindrical container with a height of lφX20+11111 and observe the state of peeling between the eyebrows. A sample with no peeling between layers was graded (○), and a sample with peeling that was not practical was graded (X).

"High temperature electrolyte resistance"...Using each of the above cylindrical containers, γ-
Immersed in each boiling liquid of butyrolactone (boiling point = 203 ° C.) and ethylene glycol (boiling point = 197 ° C.) for 1 minute,
The inner surface of the container was observed. Similarly, the container is heated to steam (18K).
g/cd) for 1 minute, then observe the inner surface of the container and evaluate the hydrolysis resistance.

From Table 1, it can be seen that samples Nos. 3 to 5, 7 and 8 of the present invention are excellent in all of peel strength, drawability and high temperature electrolyte properties. On the other hand, N with different inner resin
It can be seen that OI has excellent peel strength and drawing workability, but is inferior in high temperature electrolyte properties. In addition, NO2 with a small amount of chromate film has poor peel strength and high temperature electrolyte properties, while NO6 with too much chromate film has poor peel strength and high temperature electrolyte properties.
It can be seen that the peel strength, drawing workability, and high temperature electrolyte properties are inferior.

(Example 2) Aluminum plate (A 1100 P-H2O, thickness 0.
3011111) was treated with organic titanate using di-iso-propoxy bis(acetylacetone) titanate, and by varying the concentration, chemical conversion treatment layers having the coating amounts shown in Table 2 were obtained. The modified PP (20, um) film used in Example 1 was laminated on the treated surface by a melt lamination method.

The obtained laminate was evaluated in the same manner as in Example 1, and the results are shown in Table 2.

Here, for sample No. 015 in Table 2, the aluminum plate was subjected to boehmite treatment instead of the organic titanate treatment described above.

Boehmite treatment conditions: 80-100° using deionized water
It was treated with hot water of C. Boehmite film amount - 5mg/rr
f'.

From Table 2, it can be seen that the samples of the present invention, N0II to 13, are excellent in all of peel strength, drawability, and high temperature electrolyte properties. On the other hand, there are cases where the amount of organic titanate coating is too low, and N where the amount of titanate applied is too large.
It can be seen that 014 is inferior in peel strength, drawing workability, and high-temperature electrolytic solution resistance, and NOI coating, which is treated using a different chemical conversion treatment method, is inferior in high-temperature electrolytic solution resistance.

Example 3 Both sides of the aluminum plate used in Example 1 were subjected to chromate treatment in the same manner as in Example 1 so that the chromate peel mM was 10 mg/r+1'.

One side of this chemically treated aluminum plate was coated with the modified PP resin layer used for sample No. 4 in Example 1 using a melt lamination method, and the other side of the aluminum plate was coated with a layer of 380 PP resin.
6-nylon resin (thickness 2
0μ) was provided by a melt lamination method, and then a container (41nlllφ×5111m high) shown in the cross-sectional schematic diagram of FIG. 2.3 was obtained using a lance progressive drawing machine (7 stages).

When printing was continuously performed on the top surfaces of a plurality of containers obtained, printing was possible without occurrence of printing defects.

(Effects of the Invention) As described above, according to the outer container for electronic components of the present invention, even when soldering is performed by the reflow method, the resin on the inner surface of the outer container does not deteriorate due to the influence of the soldering temperature. It maintains insulation properties and is highly usable as an outer container for small chip-type aluminum electrolytic capacitors.

・1

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the outer container of the present invention, FIG. 2 is a sectional view showing another embodiment, and FIG. 3 is an enlarged sectional view of the part 2 in FIG. 1... Aluminum plate 11... Chemical conversion treatment layer 2...
・Modified polyolefin layer 3...Epoxy resin coating layer 4...Polyamide resin layer

Claims (1)

[Claims] The amount of chromate film is 5 on one side of the aluminum plate (1).
~150mg/m^2 or organic titanate film amount 3~
A laminate coated with a modified polyolefin resin layer (2) in which an unsaturated carboxylic acid or a derivative thereof is graft-copolymerized is coated with the modified polyolefin resin layer (2) via a chemical conversion treatment layer (11) in the range of 200 mg/m^2. An external container for electronic components that is drawn so that the inside surface faces out.