JPH07130586A - Surface treatment method of butyl rubber and composite material formed thereof - Google Patents

Abstract

PURPOSE:To provide a butyl rubber surface treating method and composite material of butyl rubber, wherein butyl rubber is utilized making the most of its properties by a method wherein the surface of butyl rubber is treated so as to be improved in adhesion properties, and butyl rubber is used as combined with other materials. CONSTITUTION:Surface treating agent whose prime component is composed of reactive siloxane and colloidal silica is applied onto the surface of a butyl rubber 1 and baked, whereby a ceramic layer 2 is formed on the surface of the butyl rubber 1, and a phenolic resin laminate 3 of prepreg sheet is bonded to the ceramic layer 2 by thermocompression to form a composite material. By this setup, a sealing sheet formed of the above composite material can be applied to an aluminum electrolytic capacitor, wherein butyl rubber is used making the most of its property that it is low in gas permeability.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is used in combination with parts that are difficult to bond with butyl rubber, especially in the field of utilizing the low gas permeability of butyl rubber, such as sealing plates and composite packings for aluminum electrolytic capacitors. The present invention relates to a butyl rubber surface treatment method and a composite material using the same, which are used when required to be used.

[0002]

2. Description of the Related Art A conventional composite material using this type of butyl rubber will be described with reference to the drawings by taking a sealing plate of an aluminum electrolytic capacitor as an example.

FIG. 5 is a sectional view showing the structure of a conventional aluminum electrolytic capacitor, FIG. 6 is a cutaway front view of a main part of a resin mold type aluminum electrolytic capacitor, and FIG. 7 is a sealing plate used in the conventional aluminum electrolytic capacitor. FIG.

In FIG. 5, the sealing plate 13 is mounted so as to insert the lead wire 10 of the capacitor element 8 housed in the aluminum case 7 together with the electrolytic solution 9 and close the upper part of the aluminum case 7. It is desirable to use butyl rubber as the rubber constituting the plate 13 from the viewpoint of preventing the leakage of the electrolytic solution 9, but it is difficult to bond the phenol resin laminated plate to the butyl rubber by the conventional surface treatment technology. The sealing plate 13 was formed by laminating the phenol resin laminated plate 3 on the ethylene / propylene copolymer rubber 12 shown in FIG.

Therefore, the product life when stored at 105 ° C. when the electrolyte 9 is glycol-based is 2,000.
Dry up in ~ 3,000 hours (a phenomenon that electrolyte 9 runs out and the capacity does not come out) and the capacitor life is 105 ° C.
However, the demand for longer life of 5,000 to 10,000 hours cannot be met, and therefore the epoxy resin 11 is cast on the top of the sealing plate 13 as shown in FIG. Thus, some capacitor manufacturers produce products that prevent the evaporation of the electrolytic solution 9 from the interface and prolong the service life. However, the epoxy resin 11 swells in the lactone-based electrolytic solution and has a drawback of high transmittance. Yes, it has not become popular.

Butyl rubber is another material, such as metal,
It is rarely used because it is difficult to bond materials such as plastics, rubber, and ceramics, and a composite of butyl rubber laminated with tetrafluoroethylene surface-treated with metallic sodium overseas is a sealing plate material for some capacitors. It was only used for.

[0007]

However, since butyl rubber is a non-polar polymer like polyethylene, polypropylene, tetrafluoroethylene, and polyphenylene sulfide, it cannot be adhered to other materials, and other materials such as adhesives cannot be used. There has been a problem that it is indispensable to establish a technique for performing surface treatment or formation of an intermediate layer to enable material adhesion.

However, butyl rubber also has a slight difference in adhesiveness depending on the vulcanizing agent, and resin vulcanization or sulfur vulcanization has better adhesiveness than peroxide vulcanization, but it can be put to practical use. is not.

Further, non-polar polymers such as polyethylene and polypropylene can be effectively irradiated with gamma rays as surface roughening for improving adhesiveness, but this is not at a practical level. In addition, a surface treatment has been put to practical use, in which tetrafluoropolyethylene is treated with a THF (tetrahydrofuran) bath in which sodium metal is dissolved to roughen the surface so that it can be bonded, but it is introduced because of its high cost. It had a complicated problem that it was difficult to use.

It is an object of the present invention to solve the above conventional problems and provide a surface treatment method of butyl rubber for improving adhesiveness and a composite material using the same.

[0011]

In order to solve the above problems, the surface treatment method of butyl rubber according to the present invention and the composite material using the same are obtained by adding a reactive siloxane to colloidal silica, and adding the reactive siloxane to butyl cellosolve and isopropyl alcohol. A surface treatment method is prepared by diluting a surface treatment agent, applying the surface treatment agent to the surface of butyl rubber, and then curing by drying and baking to form a ceramic layer on the surface of butyl rubber. A butyl rubber having a ceramic layer formed on its surface by a method, and a composite material composed of one or a plurality of materials selected from resin, metal and ceramic adhered to the ceramic layer of the butyl rubber. is there.

[0012]

By performing such a surface treatment method, when butyl rubber is coated with a surface treatment agent containing colloidal silica and a reactive siloxane as a main component and heated, the butyl rubber is infiltrated with colloidal silica. The surface layer becomes a layer close to SiO ₂ where the colloidal silica particles are exposed in order to react with the reactive siloxane to form a ceramic film and hold it.

Therefore, the butyl rubber on which the ceramic layer is formed by the surface treatment can be used with almost all adhesives such as epoxy resin type, acrylic resin type, phenol resin type silicon resin type and the like which are generally used. Simultaneous molding with a laminated board made of resin and phenol resin is also possible.

In addition to the laminate molding with other resins and rubbers, the adhesiveness can be greatly improved in insert molding such as injection molding and transfer molding.

[0015]

(Embodiment 1) A first embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a partial sectional view showing a butyl rubber having a ceramic layer formed on the surface thereof, which is obtained by a surface treatment method of butyl rubber. In FIG. 1, 1 is butyl rubber and 2 is a ceramic layer formed on the surface. Next, a surface treatment method of the butyl rubber 1 having the ceramic layer 2 thus configured will be described below.

First, colloidal silica (40% solution) ...
35 g, reactive siloxane ... 10 g, butyl cellosolve .... To the thickness of.

After coating, if the film is dried and baked at 110 ° C. for 10 minutes, the film thickness after drying becomes about 7.5 μ. If the film thickness after drying is 1 μm or less, the effect is small, and if it exceeds 50 μm, cracking tends to occur during drying and flexibility is impaired. Therefore, it seems that the film thickness of the surface treatment agent is preferably in the range of 2 to 50 μm.

(Second Embodiment) A second embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 is a partial sectional view showing a composite material using butyl rubber obtained in the same embodiment. In FIG. 2, 1 is butyl rubber, 2 is a ceramic layer, and 3 is a phenol resin laminated plate.

Next, a method for producing a composite material using the butyl rubber thus constructed will be described below.

First, the surface-treated butyl rubber 1 prepared in Example 1 was cut into a size of 30 cm × 30 cm, and the surface-treated ceramic layer 2 side of the butyl rubber 1 was coated with a low chlorine pulp and a low chlorine phenol resin. A prepreg sheet made by impregnation is placed, heated at 160 ° C. for 1 hour at a pressure of 100 kg / cm ² , and a layer of the phenolic resin laminate 3 is 1.6 mm and a butyl rubber 1 is 1 mm to produce a laminated composite plate shown in FIG. It was done.

Further, the adhesive strength between the phenol resin laminate 3 and the butyl rubber 1 was measured, but there was no interfacial peeling between the two at room temperature and 125 ° C., and all were butyl rubber 1 interlayer fractures. Therefore, it was confirmed that the adhesive strength has no practical problem.

FIG. 3 is a partial cross-sectional view showing an example in which the metal plate 5 is bonded to the ceramic layer 2 side of the butyl rubber 1 on which the ceramic layer 2 described in the above-mentioned Example 1 is bonded with the adhesive 4. Even in this case, since the ceramic layer 2 formed on the surface of the butyl rubber 1 has good adhesiveness with the adhesive 4, sufficient adhesive strength can be obtained. Needless to say, the material that can be bonded is not limited to the metal plate 5 and may be ceramic, plastic, rubber, or the like.

(Embodiment 3) A third embodiment of the present invention will be described below with reference to the drawings.

FIG. 4 is a perspective view showing a sealing plate for a capacitor prepared by punching out a composite material composed of butyl rubber and a phenol resin laminate obtained in Example 2 above.
In FIG. 4, 1 is butyl rubber, 3 is a phenol resin laminated plate, and 6 is a terminal hole.

As a result of trial production of an aluminum electrolytic capacitor (400 V withstand voltage, 120 μF) using a glycol electrolyte based on the sealing plate thus constructed, the 105 ° C. dry-up life is 6,000 to 9,000 Hr, which is a conventional product. It is possible to extend the life of the butyl rubber 1 by about 3 times, and it is possible to make the most of the low gas permeability of the butyl rubber 1.

Further, the butyl rubber 1 used for the sealing plate of the above-mentioned aluminum electrolytic capacitor has an electrolytic solution permeability of about 1/5 as compared with the conventional ethylene propylene rubber. Therefore, if the interface leak is improved, the life is further extended. Is possible.

[0029]

INDUSTRIAL APPLICABILITY As described above, the surface treatment method for butyl rubber according to the present invention and the composite material using the same are obtained by adding a reactive siloxane to colloidal silica on the surface of butyl rubber which is extremely difficult to adhere to different materials. Since a ceramic layer is formed by applying a surface treatment agent diluted with butyl cellosolve and isopropyl alcohol and heating this, adhesion and joining with other materials can be performed very easily.

As a result, it is possible to make the most of the low gas permeability of butyl rubber. For example, when a composite material of butyl rubber according to the present invention and a phenol resin laminate is used as a sealing plate of an aluminum electrolytic capacitor, It has a large contribution, such as being able to extend the life to about three times that of conventional ones, and the manufacturing method for realizing this is also inexpensive and has good mass productivity.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view showing the structure of a butyl rubber having a ceramic layer according to a first embodiment of the present invention.

FIG. 2 is a partial cross-sectional view showing a structure of a composite material in which a butyl rubber and a phenol resin laminated plate are bonded to each other according to the second embodiment.

FIG. 3 is a partial cross-sectional view showing a structure of a composite material in which a metal plate is bonded to the butyl rubber.

FIG. 4 is a perspective view showing a sealing plate for an aluminum electrolytic capacitor using the composite material according to the third embodiment.

FIG. 5 is a sectional view showing the structure of a conventional aluminum electrolytic capacitor.

FIG. 6 is a partially cutaway front view showing the structure of a conventional resin-molded aluminum electrolytic capacitor.

FIG. 7 is a partial sectional view showing the structure of a conventional composite material.

[Explanation of symbols]

 1 Butyl rubber 2 Ceramic layer 3 Phenolic resin laminate 4 Adhesive 5 Metal plate 6 Hole for terminal

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Kunio Hirao, 1006 Kadoma, Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor, Shuji Hattori, 1006 Kadoma, Kadoma, Osaka Pref.

Claims (2)

[Claims] 1. A reactive siloxane is added to colloidal silica, which is diluted with butyl cellosolve and isopropyl alcohol to prepare a surface treating agent. The surface treating agent is applied to the surface of butyl rubber and then dried and baked. A method for surface treatment of butyl rubber, which comprises curing to thereby form a ceramic layer on the surface of butyl rubber. 2. A composite material using butyl rubber having a ceramic layer formed on the surface thereof, and butyl rubber composed of one or a plurality of materials selected from a resin, a metal and a ceramic, which are bonded to the ceramic layer of the butyl rubber. .