JPH0970929A - Fluororesin composite material and port sealer of electrolytic capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluororesin composite material which is not eroded with an electrolyte and other organic solvents and exhibits excellent stickiness. SOLUTION: A capacitor element 1 contained in a case 2 is sealed by a port sealer 3, and two leads 4 are extended from the sealer 3. The sealer 3 is formed on the surface of a fluororesin sheet 3a with a primer layer 3b made of 1,2-polybutadiene and laminated on the surface with a rubber composition layer 3c mixed with a rubber and 1,2-polybutadiene. The sealer 3 is not eroded with an electrolyte and other organic solvents, and the sheet 3a and the layer 3c have excellent stickiness.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluororesin composite useful as a component or the like used in a place where solvent resistance is required and a sealing body for an electrolytic capacitor.

[0002]

2. Description of the Related Art Heretofore, as a sealing member for an electrolytic capacitor using a fluororesin, a method has been used in which a fluororesin sheet is treated with a primer and bonded simultaneously with vulcanization of rubber. Regarding the type of rubber, a copolymer of butadiene and styrene (SBR), ethylene propylene diene terpolymer (EPDM), butyl rubber (copolymer of isobutene and isoprene, IIR), etc. are used. Vulcanization with sulfur, sulfur and peroxide, and resin vulcanization such as phenol have been used. Further, a silane coupling agent has been used as a primer (for example, JP-A-55-158621).

[0003]

However, the sealing body of the conventional electrolytic capacitor has a problem that the resistance of the silane coupling agent to the electrolytic solution is poor and the rubber and the fluororesin sheet are separated from each other.

In order to solve the above-mentioned conventional problems, the present invention provides a fluororesin composite and a sealing body for an electrolytic capacitor which are not affected by an electrolytic solution and other organic solvents and have excellent adhesiveness. To aim.

[0005]

In order to achieve the above object, the fluororesin composite of the present invention comprises a fluororesin sheet having 1,2-polybutadiene applied as a primer on at least one surface thereof, and a rubber thereon. And a rubber composition layer containing 1,2-polybutadiene is laminated.

In the above structure, the rubber composition layer preferably contains 1 to 50 parts by weight of 1,2-polybutadiene when the rubber is 100 parts by weight. Further, in the above, the thickness of the fluororesin sheet is 0.1 to 1.5.
It is preferable that the thickness is in the range of mm, the thickness of the primer is in the range of 0.5 to 20 μm, and the thickness of the rubber composition layer is in the range of 0.1 to 5 mm.

Next, the sealing body of the electrolytic capacitor of the present invention uses the above-mentioned fluororesin composite.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The rubber for forming the rubber composition layer is not particularly limited, and includes SBR, EPDM, IIR,
Isoprene rubber (IR), butadiene rubber (BR), chloroprene rubber (CR), acrylonitrile-butadiene rubber (NBR), ethylene-propylene rubber (EP
Synthetic rubber or natural rubber such as M) can be used, but electrolytic solution resistance such as a sealing body of an electrolytic capacitor,
When heat resistance and oxidation resistance are required, it is particularly preferable to select and use IIR.

A vulcanizing agent is added to these rubbers. The method of vulcanizing the rubber is not particularly limited, and sulfur vulcanization, resin vulcanization, peroxide vulcanization or the like can be adopted. Alkylphenol formaldehyde resin, octylphenol-formaldehyde resin, etc. are used for resin vulcanization, and dicumyl peroxide (DCP), tert-butyl cumyl peroxide, 2,2-bis (tertiary butylperoxy) for peroxide vulcanization. ) Octane, 2,5-dimethylhexane 2,5-dihydroperoxide and the like are used. These vulcanizing agents are usually mixed in an amount of about 1 to 5 parts by weight with respect to 100 parts by weight of rubber. Further, as a vulcanization aid, vulcanization accelerator or co-vulcanization agent, polyhydric alcohol methacrylate, acrylate, trimethylolpropane trimethacrylate (TMTP), triallyltriisocyanurate (T
AIC) and the like can be added, and these are usually used in an amount of about 1 to 5 parts by weight based on 100 parts by weight of rubber.

If desired, the rubber may be clay,
Talc, mica, calcium carbonate, carbon black,
Fillers such as bentonite, magnesium carbonate, barite, titanium oxide, white carbon and silica can be blended. These fillers are usually mixed in an amount of about 1 to 100 parts by weight with respect to 100 parts by weight of rubber.

In the present invention, the rubber composition layer forming component and the primer 1,2-
Use polybutadiene. As the 1,2-polybutadiene, those having various molecular weights can be used, but those having an average molecular weight of about 5,000 to 50,000 are preferable. It is preferable that 1 to 50 parts by weight of 1,2-polybutadiene as a rubber composition layer forming component is blended with 100 parts by weight of rubber. Also used as a primer 1,2
If desired, the polybutadiene can be compounded with a vulcanizing agent, in which case usually 1,2-polybutadiene 1
About 1 to 10 parts by weight is blended with 00 parts by weight.

As the fluororesin sheet, polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (P
FA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), ethylene-tetrafluoroethylene copolymer (ETFE), polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (PC)
A sheet made of at least one resin selected from TFE) and the like can be used.

In the present invention, it is preferable that the coating surface of the fluororesin sheet is coated with 1,2-polybutadiene. As a method for the adhesion treatment, any known method such as corona discharge treatment, plasma treatment, sputter etching treatment, and metallic sodium treatment can be adopted, but from the viewpoint of treatment effect, sputter etching treatment is preferable. In this sputter etching process, a high-frequency voltage is applied between the negative and positive electrodes under a reduced pressure atmosphere in a pressure resistant container to accelerate the cations generated by the discharge in the dark part of the cathode where the ion energy in the discharge region is large, and the target object It is to collide with the surface (the surface of the fluororesin sheet).

In the sputter etching treatment, various atmosphere gases can be used, but in practice, air, an inert gas such as argon or helium, nitrogen gas, carbon dioxide gas or water vapor is preferable. The atmospheric pressure is usually about 0.005-0.5 Torr, the discharge power is usually 0.1-5 W / cm ² , and the discharge treatment amount (product of discharge power and treatment time) is usually about 0.1. ~ 100W ・ s
ec / cm ² , preferably 30 to 70 W · sec / cm
Set to be ^2. Regarding the sputter etching treatment for fluororesin and the apparatus used for this, Japanese Patent Publication No. 53-22108 and Japanese Patent Publication No. 56-13.
No. 37, Japanese Patent Publication No. 56-1340 and the like can be referred to.

The desired fluororesin composite can be obtained by applying 1,2-polybutadiene to the fluororesin sheet and vulcanizing and adhering it to the rubber compounded as described above.

[0016]

EXAMPLES The present invention will be described more specifically below with reference to examples. In the following examples, parts indicate parts by weight.

(Example 1) PTFE having a thickness of 0.8 mm
One side of the sheet was sputter-etched in a 10 ⁻² torr vacuum container. At this time, water vapor was used as the atmosphere gas, the discharge power was 2 W / cm ² , and the treatment time was 25 seconds.

Next, the unvulcanized rubber having the composition shown in Table 1 below was prepared by using a two-roll rubber or an internal mixer.
Kneading according to the method described in "Rubber Test Method" (edited by Japan Rubber Association), pp. 150-172, thickness of 1 m
m sheets were prepared.

[0019]

[Table 1]

5 parts by weight of dicumyl peroxide was blended with 100 parts by weight of 1.2-polybutadiene, and this was diluted with toluene and applied to the sputter-etched surface of the PTFE sheet. This and the above rubber sheet were stuck together. As a method for laminating, a press was applied for 15 minutes under the conditions of a temperature of 170 ° C. and a pressure of 10 kg / cm ² .

The composite thus prepared had an adhesive force enough to cause cohesive failure of rubber. The composite was dipped in an electrolytic solution of an electrolytic capacitor, put under the condition of 85 ° C. × 250 h, and taken out. As a result, the rubber had an adhesive force enough to cause cohesive failure.

FIG. 1 shows an example in which the fluororesin composite obtained as described above is applied to a sealing body of an electrolytic capacitor. FIG. 1 is a sectional view of an electrolytic capacitor according to an embodiment of the present invention. The capacitor element 1 housed in the case 2 is sealed by a sealing body 3, and two lead wires 4 are led out from the sealing body 3 to the outside. The sealing body 3 is
A primer layer 3b made of 1,2-polybutadiene is formed on the surface of the fluororesin sheet 3a, and a rubber composition layer 3c containing butyl rubber and 1,2-polybutadiene is laminated on the surface of the primer layer 3b. The sealing body 3 is not attacked by the electrolytic solution and other organic solvents, and is a fluororesin sheet 3
It was confirmed that a and the rubber composition layer 3c showed excellent adhesiveness.

Comparative Example 1 A composite sheet prepared under the same conditions as in Example 1 except that the primer was γ-mercaptopropyltrimethoxysilane was immersed in an electrolytic solution of an electrolytic capacitor at 85 ° C. for 250 hours. When put into the condition and taken out, the primer was attacked by the electrolytic solution and the PTFE sheet and the rubber were peeled off.

[0024]

As described above, the fluororesin composite of the present invention has at least one surface of the fluororesin sheet,
By applying 1,2-polybutadiene as a primer and laminating a rubber composition layer in which 1,2-polybutadiene is mixed with rubber, excellent adhesion is obtained without being attacked by an electrolytic solution and other organic solvents. It is possible to realize a sealing body for a fluororesin composite and an electrolytic capacitor exhibiting properties.

[Brief description of drawings]

FIG. 1 is a sectional view of an electrolytic capacitor according to an embodiment of the present invention.

[Explanation of symbols]

 1 Capacitor element 2 Case 3 Sealing body 3a Fluororesin sheet 3b Primer layer 3c Rubber composition layer 4 Lead wire

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Claims (3)

[Claims] 1. A fluororesin composite in which 1,2-polybutadiene is applied as a primer on at least one surface of a fluororesin sheet, and a rubber composition layer obtained by mixing 1,2-polybutadiene with rubber is laminated thereon. . 2. The rubber composition layer comprises butyl rubber 10
When the amount is 0 parts by weight, 1 to 5 parts of 1,2-polybutadiene are added.
The fluororesin composite according to claim 1, which is blended in an amount of 0 part by weight. 3. A sealing body for an electrolytic capacitor, which uses the fluororesin composite according to claim 1.