JPH0671783B2 - Laminate - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated body useful as a packing for capacitors and the like for sealing the case opening of an electrolytic capacitor.

[0002]

2. Description of the Related Art Generally, an electrolytic capacitor has a case, a capacitor element housed in the case, an electrolytic solution impregnated in the capacitor element, and an opening of the case. The packing is configured to prevent the electrolytic solution from being evaporated and the leads are drawn from the capacitor element and penetrate the packing. Conventionally, the packing is made of vulcanized rubber such as styrene-butadiene rubber and ethylene-propylene-terpolymer.

On the other hand, in recent years, in order to secure stable characteristics over a wide temperature range, a solvent such as N, N-dimethylformamide or γ-butyrolactone has been used as an electrolytic solution. These solvents have high solubility in the above vulcanized rubber and high volatility. Therefore, by the above electrolyte,
The packing made of vulcanized rubber is violated, and the electrolytic solution easily volatilizes from the case. Especially when the temperature is high, this tendency is remarkable. When the electrolytic solution volatilizes, it adversely affects the operability of the electrolytic capacitor.

In view of the above points, JP-A-62-27681
No. 9 and Japanese Patent Laid-Open No. 63-229809 propose electrolytic capacitors in which the opening of the case is sealed with an elastic packing in which cross-linked butyl rubber is cross-linked with organic peroxide or the like. According to these elastic packings, since butyl rubber having a small gas permeability is used, it is possible to prevent volatilization of the electrolytic solution, and since it is crosslinked, it is excellent in heat resistance with little heat deterioration and aging.

However, since the packing is an elastic body made of cross-linked butyl rubber, its mechanical strength is still small,
Moreover, it is easily elastically deformed. Therefore, when the opening of the case is sealed while inserting the lead terminal into the insertion hole of the packing, the packing is likely to be deformed and the tight sealing property may not be ensured. In this regard, the actual Kaihei 1-156536
The publication discloses a solid electrolytic capacitor in which the opening of the case is sealed with a fluorine-based rubber packing, and an epoxy resin is injected onto the rubber packing to form a thermosetting resin layer. However, since the rubber packing is made of fluorine-based rubber, it is not only expensive, but also has a small adhesive force with the epoxy resin. Therefore, the electrolytic solution easily exudes and volatilizes through the interface between the rubber packing and the thermosetting resin layer and the gap between the inner wall of the case and the end surface of the thermosetting resin layer.

Further, as a packing for a capacitor, after irradiating the surface of a vulcanized rubber sheet with ultraviolet rays or an electron beam, it is stacked with a resin-impregnated base material impregnated with a synthetic resin such as phenol resin, and the whole is heated and pressed to be laminated. , A method of curing and adhering has been proposed (JP-A-54-108885,
Japanese Examined Patent Publication No. 60-17338, Japanese Utility Model Publication No. 54-1413
No. 56).

However, this method requires a surface treatment step, so that the workability and the productivity are deteriorated, and the obtained laminate is expensive. Also,
In the method by surface treatment, the degree of surface treatment is likely to change depending on the type of rubber sheet as the treated substrate and the treatment conditions, so the adhesiveness between the resin-impregnated substrate and the rubber sheet tends to fluctuate, and the adhesiveness and integrity are improved. It is difficult to efficiently manufacture an excellent laminate.

Accordingly, it is an object of the present invention to provide a laminate which is excellent in heat resistance, solvent resistance, mechanical strength and gas impermeability, and is also excellent in adhesion between a rubber sheet and a phenol resin-containing sheet. is there.

Another object of the present invention is to provide a laminated body capable of suppressing corrosion of electrodes and the like when applied to a capacitor element or the like.

[0010]

The present inventors have made earnest studies as a result of paying attention to the fact that the partially crosslinked butyl rubber has a vulcanizable vinyl group. As a result, (a) the partially crosslinked butyl rubber having the vinyl group When a rubber sheet vulcanized by adding an organic peroxide is stacked with a phenol resin-containing sheet and laminated by heating and pressing, a laminate having excellent adhesion can be obtained, (b) containing a phenol resin It was found that corrosion of the electrodes of the capacitor element can be suppressed by reducing the electrolyte component of at least the phenol resin-containing sheet of the sheet and the rubber sheet, and the present invention has been completed. That is, the present invention is a laminate in which a phenol resin-containing sheet and a rubber sheet are laminated, wherein the rubber sheet is a partially cross-linked butyl rubber formed of a copolymer of isobutylene, isoprene, and divinylbenzene by organic peroxide. Provided is a laminate which is a vulcanized butyl rubber sheet.

The present invention also provides a laminate in which the phenolic resin-containing sheet is composed of a reinforcing base material and a phenolic resin.

Further, the present invention provides a laminate in which at least the phenol resin-containing sheet among the phenol resin-containing sheet and the rubber sheet has a low electrolyte property.

Partially crosslinked butyl rubber is a copolymer of isobutylene, isoprene and divinylbenzene,
The vinyl group remains. As such butyl rubber,
For example, trade names of Polycer Butyl XL10000, XL68102, XL30102 and the like manufactured by Polcer International Co., Ltd. are exemplified. The partially crosslinked butyl rubber may be used in combination with other rubber such as ethylene-propylene rubber and ethylene-propylene-non-conjugated diene rubber as long as the characteristics of the butyl rubber are not impaired.

The partially crosslinked butyl rubber is vulcanized with an organic peroxide. Examples of the organic peroxide include lauroyl peroxide, benzoyl peroxide, 2,2.
4-dichlorobenzoyl, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane,
Ethyl methyl ketone peroxide, n-butyl-4,4
-Bis (t-butylperoxy) barrel, dicumyl peroxide, t-butylcumyl peroxide, di-t-butyl peroxide, α, α-bis (t-butylperoxy) diisopropylbenzene, 2,5-dimethyl-2,
Examples include various organic peroxides such as 5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (t-butylperoxy) hexene-3, and t-butylperoxycumene. The above organic peroxides are used alone or in combination of two or more. The amount of organic peroxide is usually 1 to 15 parts by weight, preferably 2.
It is about 5 to 10 parts by weight. The vulcanization is, for example, 1
It can be performed at about 00 to 200 ° C.

The vulcanized rubber sheet may contain various additives. When an activator, such as a polyhydric alcohol and its derivative or amine, is added as an additive, the adhesion with the phenol resin-containing sheet can be further increased. Examples of the polyhydric alcohol and its derivative include, for example, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol,
Examples include tripropylene glycol, polypropylene glycol, 1,4-butanediol, 1,6-hexanediol, and derivatives thereof. Examples of amines include diethanolamine and triethanolamine. These activators may be added singly or in combination of two or more, and may be added in an amount of 1 to 25 parts by weight, preferably 2 to 10 parts by weight, based on 100 parts by weight of the partially crosslinked butyl rubber.

Further, the vulcanized rubber sheet may be a vulcanized rubber sheet using a polymerizable monomer having at least one unsaturated double bond, preferably two or more, as a vulcanization aid. Examples of the polymerizable unsaturated group of the polymerizable monomer include a vinyl group, an allyl group, an acryloyl group or a methacryloyl group. As the polymerizable monomer, for example, a compound having a vinyl group such as divinylbenzene; diallyl itaconate, diallyl phthalate,
Compounds having an allyl group such as triallyl phosphate, triallyl cyanurate and triallyl isocyanurate; alkyl acrylates having about 1 to 18 carbon atoms, cyclohexyl acrylate, tetrahydrofurfuryl acrylate, isobornyl acrylate, phenyl acrylate, benzyl acrylate, etc. Having an alkyl group, an aryl group or the like; an acrylate having a hydroxy group such as 2-hydroxyethyl acrylate or 2-hydroxypropyl acrylate; an acrylate having an alkoxy group or an aryloxy group such as butoxyethyl acrylate or 2-phenoxyethyl acrylate 2-acryloyloxyethyl succinic acid, 2
-Acryloyloxypropyl succinic acid, 2-acryloyloxyethyl phthalic acid, 2-acryloyloxypropyl phthalic acid and other acrylates; glycidyl acrylate and other glycidyl group acrylates; acrylamide, dimethylaminoethyl acrylate, diethylaminoethyl acrylate Acrylates having amide groups or alkylamino groups such as ethylene glycol diacrylate, diethylene glycol diacrylate, polyethylene glycol diacrylate, propylene glycol diacrylate, dipropylene glycol diacrylate, polypropylene glycol diacrylate, butanediol diacrylate, hexanediol di Acrylate, neopentyl glycol diacrylate Glycerol triacrylate, 2,
2-bis (4-acryloyloxyethoxyphenyl)
Propane, 2,2-bis (4-acryloyloxydiethoxyphenyl) propane, 2,2-bis (4-acryloyloxypropoxyphenyl) propane, 2,2-
Bis (4-acryloyloxydipropoxyphenyl)
Propane, 2,2-bis (4-acryloyloxypolypropoxyphenyl) propane, trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, N, N'-
Examples thereof include polyfunctional monomers such as methylenebisacrylamide, tris (2-acryloyloxy) isocyanurate, and dipentaerythritol ipiron caprolactone acrylate; and methacrylates corresponding to these acrylates. The polyfunctional monomer includes a monomer having an acryloyl group and a methacryloyl group in the molecule, for example, 3-acryloyloxyglycerin monomethacrylate, 2-hydroxy-3-acryloyloxypropyl methacrylate, epoxy acrylate, polyester acrylate, urethane. Also included are acrylates, silicone acrylates, melamine acrylates, and the like.

The amount of the polymerizable monomer added is usually 0 to 30 parts by weight based on 100 parts by weight of the partially crosslinked butyl rubber,
It is preferably 1 to 20 parts by weight.

In addition, the rubber sheet may contain various other additives,
For example, co-vulcanizing agents such as metal oxides; vulcanization accelerators such as guanidines, thioureas, thiazoles, sulfenamides, thiurams, dithiocarbamates, xanthates; zinc vulcanization Auxiliaries: vulcanization retarders such as sulfenamide compounds; antioxidants, antioxidants such as UV absorbers; carbon black, silicic acid anhydride, calcium silicate, aluminum silicate, clay, rayon, nylon, Reinforcing agents such as synthetic fibers such as polyester and aromatic polyamide, carbon fibers, glass fibers, etc .; fillers or increasing amount of calcium carbonate, talc, barium sulfate, alumina sulfate, lithopone, styrene resin, phenol resin, petroleum resin, recycled rubber, etc. Agents; linoleic acid, oleic acid, tall oil and other softening agents; plasticizers; alkylphenol resins, - indene resins, tackifiers such as rosin derivatives; may contain coloring agents; stearic acid, metallic soaps of stearic acid, processing aids or lubricants, such as wax.

The thickness of the vulcanized rubber sheet is usually about 0.1.
It is about 5 mm.

The phenol resin-containing sheet may be a sheet of phenol resin alone, but is usually preferably an impregnated sheet obtained by impregnating a reinforcing substrate with a phenol resin. Examples of the reinforcing base material include paper; woven and non-woven fabrics made of natural or synthetic fibers, glass fibers, carbon fibers and the like. The phenol resin-containing sheet is preferably made of impregnated paper impregnated with a phenol resin, particularly a resol type phenol resin.

The above-mentioned phenol resin-containing sheet can be constructed by using an appropriate number of, for example, 5 to 20 sheets of phenol resin-impregnated paper, and the thickness thereof is usually about 0.5 to 5.
It is about mm.

It is preferable that the rubber sheet and the phenol resin-containing sheet constituting the laminate have a low electrolyte property with a small amount of corrosive electrolyte components that corrode the electrodes, for example, chlorine components and sulfate components. . Particularly, it is preferable that at least the amount of the electrolyte component of the phenol resin-containing sheet is small. The amount of the electrolyte component cannot be unconditionally specified because it depends on the application of the laminate, but for example, when it is used as a sealing material for an electrolytic capacitor in which electrodes are attached to the laminate, the total content of chlorine and sulfate is For example, it is 10 ppm or less, preferably 5 ppm or less.

A laminate having a remarkably high adhesive strength between the vulcanized rubber sheet and the phenol resin-containing sheet is an unvulcanized rubber sheet containing partially cross-linked butyl rubber and organic peroxide,
Alternatively, it can be obtained by stacking a vulcanized rubber sheet obtained by vulcanizing partially crosslinked butyl rubber with an organic peroxide and a phenol resin-containing sheet, and heating and pressurizing them to integrate them. Even when a vulcanized rubber sheet is used, a laminated body with high adhesive strength can be obtained because (1) the affinity between the vulcanized rubber sheet and the phenol resin is large, and (2) the heating and pressing process It is presumed that this is due to the reaction between the radicals generated by the peroxide remaining on the sulfurized rubber sheet and the phenol resin. In the phenol resin-containing sheet, the phenol resin before being laminated with the rubber sheet is used in an uncured state. The uncured phenol resin firmly adheres to the rubber sheet by heating and pressing. It is considered that this is because the phenol resin once flows due to heating at the time of heating and pressurization, receives pressure, escapes air in the resin, and then cures.

The heating and pressurizing step is carried out under appropriate conditions such as a press pressure of about 30 to 150 kg / cm ² , a temperature of about 100 to 200 ° C., and a pressurizing time of about 30 minutes to 6 hours. It can be done under conditions.

In the present invention, since the vulcanized rubber sheet is obtained by vulcanizing the partially cross-linked butyl rubber having a small gas permeability and excellent heat resistance with an organic peroxide, the heat resistance of the vulcanized rubber sheet is improved. It can be further enhanced,
It exhibits excellent solvent resistance even in highly soluble solvents such as N, N-dimethylformamide. In addition, since it is vulcanized with a peroxide, it is possible to prevent various problems derived from the use of a vulcanizing agent, for example, conventional sulfur, such as contamination of an electrolytic solution with free sulfur. Further, the phenolic resin-containing sheet has excellent insulating properties and heat resistance, and even if it is used as a packing material for a capacitor, it is hardly deteriorated by heat. In addition, when the phenolic resin-containing sheet is produced by using the reinforcing base material, the strength becomes high, so that the contained sheet can be made thin, and the electrolytic capacitor can be downsized.

The laminate of the present invention is suitable not only for the packing for capacitors but also for various packings, insulating sheets, protective sheets, etc., which are required to have adhesiveness, integrity and heat resistance.

[0027]

According to the laminate of the present invention, the heat resistance, the electrolytic solution resistance, the corrosion resistance to the electrodes and the mechanical strength are excellent, the gas permeability is small, and the rubber sheet and the phenol resin-containing sheet are provided. It has excellent adhesion.

If at least the phenolic resin-containing sheet has a low electrolyte property, the corrosion resistance of the electrode can be further enhanced.

[0029]

EXAMPLES The present invention will be described in more detail based on the following examples.

Examples 1 to 3 and Comparative Example 1Resin-containing sheet  Paper base is impregnated with resol-type phenol resin and dried.
The impregnated paper containing uncured phenolic resin.
Along with manufacturing, stacking a specified number of impregnated papers and containing resin
A sheet was prepared.

[0031]Unvulcanized rubber composition and unvulcanized rubber sheet  The following compositions (1) to (7) were used as standard compositions.

(1) 100 parts by weight of partially crosslinked butyl rubber (manufactured by Polycer International Co., Ltd., trade name Polycerbutyl XL10000), (2) carbon black as a reinforcing agent (manufactured by Asahi Carbon Co., Ltd., trade name Asahi 35 (SRF)) ) 8 parts by weight, (3) 20 parts by weight of magnesium silicate (trade name: Hytron A manufactured by Takehara Chemical Industry Co., Ltd.) as a reinforcing agent, (4) Burgess # 30 (Berges Pigment as an extender) 200 parts by weight, (5) Zinc Hua No. 1 (manufactured by Shodo Chemical Co., Ltd.), 5 parts by weight, (6) Processing aid, stearic acid (manufactured by NOF Corporation) as a dispersant. 5 parts by weight, (7) Sulfur as a co-vulcanizing agent 0.4 parts by weight (1) to (7)
(8) 2 parts by weight of trimethylolpropane trimethacrylate (manufactured by Kyoeisha Oil & Fat Chemical Co., Ltd., trade name Light Ester TMP) as a vulcanization aid, (9) polyethylene glycol (manufactured by NOF Corporation) , (Trade name: PEG-4000), 3 parts by weight, (10) Organic peroxide (manufactured by Kayaku Nouri Co., Ltd., trade name: Trigonox 29/40 MB) 0 part by weight (Comparative Example 1), 2
An unvulcanized rubber composition was prepared by adding 5 parts by weight (Example 1), 3.5 parts by weight (Example 2), and 5 parts by weight (Example 3). These unvulcanized rubber compositions were formed to a thickness of 1.0 mm to prepare unvulcanized rubber sheets.

Next, the unvulcanized rubber sheet is vulcanized at a temperature of 160 ° C., laminated with a resin-containing sheet, and heated and pressed for 1 hour under the conditions of a pressing pressure of 80 kg / cm ² , temperatures of 140 ° C. and 147 ° C. Then, a cooling press was carried out for 30 minutes with the pressure kept as it was to produce a laminate having a thickness of 2.0 mm.
Then, the adhesion between the vulcanized rubber sheet and the resin-containing sheet of the laminate was evaluated according to the following criteria, and the results shown in Table 1 were obtained.

Excellent: Peeling is difficult and the vulcanized rubber sheet breaks. Good: Peeling is difficult and interfacial fracture occurs. No: Easy peeling.

[0035]

[Table 1] From Table 1, the vulcanized rubber sheet obtained by vulcanizing the partially cross-linked butyl rubber with the organic peroxide has a large adhesion with the phenol resin-containing sheet.

Examples 4 to 6 In addition to the above components (1) to (7), (8) trimethylolpropane trimethacrylate as a vulcanization aid (Kyoeisha Oil and Fat Chemical Co., Ltd., trade name Light Ester TMP) 2 parts by weight, (10) 3.5% by weight of organic peroxide (manufactured by Kayaku Nouri Co., Ltd., trade name Trigonox 29/40 MB), (9) polyethylene glycol (manufactured by NOF Corporation, trade name PEG-) 4000) 1 part by weight (Example 4), 2 parts by weight (Example 5), and 5 parts by weight (Example 6) were added, and a laminate was prepared in the same manner as in Example 1.

Then, the adhesion between the vulcanized rubber sheet and the resin-containing sheet of the laminate was evaluated according to the same criteria as above, and the results shown in Table 2 were obtained. The data of Example 2 are also shown in Table 2. In addition, in Table 2, PEG represents polyethylene glycol.

[0038]

[Table 2] From Table 2, the adhesion is increased by adding polyethylene glycol.

Examples 7 and 8 In addition to the components (1) to (7), (9) 3 parts by weight of polyethylene glycol (trade name: PEG-4000, manufactured by NOF CORPORATION), (10) organic peroxide (Kayaku Nouri Co., Ltd., trade name Trigonox 29 / 40MB) 3.5 parts by weight, (8) trimethylolpropane trimethacrylate as a vulcanization aid (Kyoeisha Yushi-Kagaku Co., Ltd., trade name light ester) TMP) was added in an amount of 0 part by weight (Example 8) and 5 parts by weight (Example 9), and a laminate was prepared in the same manner as in Example 1.

Then, the adhesion between the vulcanized rubber sheet and the resin-containing sheet of the laminate was evaluated according to the same criteria as above, and the results shown in Table 3 were obtained. The data of Example 2 are also shown in Table 3. In addition, in Table 3, TMP represents trimethylolpropane trimethacrylate.

[0041]

[Table 3] Example 9 In place of the vulcanized rubber sheet, an unvulcanized rubber sheet having the same composition as in Example 2 was laminated with a resin-containing sheet, and heat-pressed and vulcanized in the same manner as in Example 2 to give Example 2. Similar results were obtained. The adhesion was 1.3 kgf / cm, which is the strength of the vulcanized rubber sheet.

Example 10 Unsolicited base paper (chlorine component: 4 ppm) was impregnated with a resole-type phenol resin (chlorine component: 1 ppm or less) and dried,
An impregnated paper holding an uncured phenol resin was prepared, and a predetermined number of impregnated papers were stacked to prepare a resin-containing sheet (chlorine component: 2 ppm).

The resin-containing sheet and the rubber sheet used in Example 2 were stacked, heated and pressed for 1 hour under the conditions of a pressing pressure of 80 kg / cm ² and a temperature of 160 ° C., and a cooling press was used for 30 minutes under the pressure. 2.5mm thick by doing for a minute
A laminated body of was prepared.

Then, a simple capacitor having the above-mentioned laminated body as a sealing material was prepared and subjected to a corrosion acceleration test of an aluminum lead wire under the condition of 100 ° C. for 50 hours. No corrosion of the aluminum lead wire was observed. .

Comparative Example 2 A raw paper (chlorine component: 30 ppm) was impregnated with a resole-type phenol resin (chlorine component: 1 ppm or less) and dried,
An impregnated paper holding an uncured phenolic resin was prepared and a predetermined number of impregnated papers were stacked to prepare a resin-containing sheet (chlorine component: 15 ppm).

Then, in the same manner as in Example 10, a laminated body and a simple capacitor were prepared, and an aluminum lead wire corrosion-acceleration test was conducted. Corrosion of the aluminum lead wire was observed.

Claims (3)

[Claims] 1. A laminate in which a phenol resin-containing sheet and a rubber sheet are laminated, wherein the rubber sheet is a partially cross-linked butyl rubber made of a copolymer of isobutylene, isoprene and divinylbenzene, and an organic peroxide. A laminated body, which is a butyl rubber sheet vulcanized by. 2. The laminate according to claim 1, wherein the phenol resin-containing sheet is composed of a reinforcing base material and a phenol resin. 3. The laminate according to claim 1, wherein at least the phenol resin-containing sheet among the phenol resin-containing sheet and the rubber sheet has a low electrolyte property.