JPH0723436B2 - Electrolytic capacitor- - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to an electrolytic capacitor which is encapsulated by a mixture of three ethylene-based copolymers and a rubber cross-linked product and carbon black. More specifically, an ethylene copolymer (A), (B) having at least (A) an ethylene unit and at least one unit selected from the group consisting of unsaturated dicarboxylic acid units, anhydride units thereof and half ester units thereof. ) Ethylene copolymer having at least ethylene unit and unsaturated hydroxyl unit (B), (C) Ethylene copolymer having at least ethylene unit and unsaturated epoxy unit (C), (D) carbon black, ( E) at least one Mooney viscosity (ML _{1 + 4} , 100 ° C.) selected from the group consisting of acrylic rubber, isoprene-isobutene copolymer rubber, isobutylene rubber, hydrogenated copolymer rubber of acrylonitrile and butadiene, and silicone rubber. )But
The present invention relates to an electrolytic capacitor which is sealed with a mixture of an ethylene-based copolymer of a mixture of a rubber and (F) an organic peroxide having a ratio of 160 or less, and a mixture having a cross-linked product of the rubber. Not only is it sufficiently resistant, it has extremely high heat resistance that can withstand solder sufficiently, cross-linking is relatively easy, and the adhesion to the case and lead wire is also excellent. It is an object to provide an electrolytic capacitor sealed with a resin.

2. Description of the Related Art With the development of the electronic industry, various capacitors have been developed, and the growth of capacitors for electronic devices is particularly remarkable. Recently, the growth of electrolytic capacitors has been remarkably increasing due to downsizing, large capacity and cost reduction. As a typical example of this electrolytic capacitor, high-purity aluminum is used as an anode, and a layer in which aluminum oxide is formed to have a uniform thickness on the surface of the anode by electrolyzing this in a liquid electrolyte is used as a dielectric. There are aluminum electrolytic capacitors, dry electrolytic capacitors that use a jury liquid as the cathode, and solid electrolytic capacitors that use solid semiconductors and conductors, and these capacitors occupy the majority.

In terms of capacity, from the tube type of about 0.05cc widely used mainly for transistor radios, etc., 1
The metal case type of about 0,000cc is also used. In recent years, solid electrolytic capacitors have become smaller, and a tube type system has been developed in which the electrodes are taken out from the sealing port using manganese dioxide, carbon, solder, etc. without using a cathode electrolytic capacitor. .

Conventionally, these electrolytic capacitors have been sealed with a thermosetting resin, a room temperature curable resin, a photocurable resin, or the like to prevent moisture from entering and to secure airtightness inside. However, with these curable resins, not only the production efficiency is poor because the curing time is relatively long, but also the liquid leakage occurs due to insufficient adhesion to the capacitor case, and the cathode liquid (for example, , Glycerin ethylene glycol, boric acid, ammonia, etc.), or due to hygroscopicity, moisture is absorbed from the sealing port and the concentration of the electrolyte inside changes, which shortens the life. In addition, recently, with downsizing, since solder is used for fixing to a printed circuit board or the like, there is a problem that the solder heat is transmitted through the lead wire and melts the sealing portion. Further, when carbon black was not added, there was a problem that the sealing portion of the electrolytic capacitor had the most necessary compression set and damage due to compression, that is, the tearability was not good. Also, if you do not compound the rubber,
The electrolytic capacitor itself was hard, and only a high hardness was obtained. Further, a highly elastic material was not obtained, and there was a problem in terms of flexibility and the like.

From these facts, some of the present inventors selected as a sealing material for an electrolytic capacitor from the group consisting of (A) at least ethylene and a carboxylic acid unit, a dicarboxylic acid unit, an anhydride unit thereof and a half ester unit. An ethylene copolymer comprising at least one unit, and (B) an ethylene copolymer comprising at least an ethylene unit and at least one unit selected from the group consisting of a hydroxyl unit, an amino unit and a glycidyl unit, ( C)
A crosslinked product of a mixture of carbon black, (D) special rubber and (E) organic peroxide was previously proposed (Japanese Patent Application No. 60-198661). However, the crosslinked product of the obtained mixture is not always satisfactory in heat resistance.

Problems to be Solved by the Invention From the above, the present invention does not have these drawbacks (problems), and is flexible, not only excellent in compression set, but also excellent in mechanical strength, It is capable of cross-linking in a short time, not only has sufficient resistance to electrolytes, but also has extremely high heat resistance that can withstand solder sufficiently, and also has excellent adhesion to the case and lead wires. It is to obtain an electrolytic capacitor which is sealed with a synthetic resin.

Means and Actions for Solving the Problems According to the present invention, these problems are (A) "from the group consisting of at least ethylene and unsaturated dicarboxylic acid units, their anhydride units and their half ester units. "Ethylene-based copolymer having at least one type of unit selected and having an ethylene unit content of 30 to 99.5% by weight" [hereinafter referred to as "ethylene-based copolymer (A)"], (B) " It is composed of at least ethylene units and unsaturated hydroxyl units, and the content of ethylene units is 30 to 99.5.
% Of ethylene-based copolymer [hereinafter referred to as "ethylene-based copolymer (B)"], (C) "contains at least ethylene units and unsaturated epoxy units, and has an ethylene unit content of 30. To 99.5% by weight of ethylene-based copolymer [hereinafter referred to as "ethylene-based copolymer (C)"], (D) carbon black, (E)
At least one Mooney viscosity (ML _{1 + 4} , 1 selected from the group consisting of acrylic rubber, isoprene-isobutene copolymer rubber, isobutylene rubber, hydrogenated copolymer rubber of acrylonitrile and butadiene, and silicone rubber.
(F) is a mixture consisting of rubber having a temperature of 00 ° C. or less and (F) an organic peroxide, and the mixing ratio of the ethylene copolymer (A) in the total amount of these ethylene copolymers is 1 to 99% by weight, and the mixing ratio of the ethylene-based copolymer (C) in the total amount of the ethylene-based copolymer (B) and the ethylene-based copolymer (C) is 10 to 80% by weight, The mixing ratio with respect to 100 parts by weight of the total amount of these ethylene-based copolymers is 1.0 to 1 for carbon black.
20 parts by weight, and 0.1 to 50 parts by weight for rubber, and 0.1 to 10 parts by weight for organic peroxide, in a mixture having a mutual cross-linking of ethylene copolymers as well as a cross-linked rubber. It can be solved by an electrolytic capacitor that is sealed. Hereinafter, the present invention will be specifically described.

(A) Ethylene-based Copolymer (A) The ethylene-based copolymer (A) used in the present invention is selected from the group consisting of at least ethylene unit and "unsaturated dicarboxylic acid unit, its anhydride unit and its half-ester unit. At least one type of unit, which is referred to as the "second component (A)" below, and its ethylene unit is 30
It is an ethylene-based copolymer containing 99.5% by weight.

This ethylene-based copolymer (A) is a copolymer that can be obtained by copolymerizing the following monomers in order to constitute at least the second component (A), and multi-component copolymers of these and other monomers. Examples thereof include those obtained by hydrolyzing and / or alcohol-modifying the acid anhydride groups in the polymers and their copolymers.

Typical examples of this monomer include maleic acid, phthalic acid, tetrahydrophthalic acid, 4-methylcyclohexane-4-ene-1,2-carboxylic acid, itaconic acid, citraconic acid and bicyclo (2,2,1) -hepta acid. -5-ene-2,3
And unsaturated dicarboxylic acids having 4 to 50 carbon atoms such as dicarboxylic acids and anhydrides of these unsaturated dicarboxylic acids.

In addition, as other monomers, unsaturated such as methyl (meth) acrylate, ethyl (meth) acrylate, hydroxymethyl (meth) acrylate and diethyl fumarate having at most 30 (preferably 10 or less) carbon atoms. Examples include carboxylic acid esters and vinyl esters having at most 30 carbon atoms such as vinyl acetate and vinyl propionate.

Of the above ethylene-based copolymers (A), a copolymer of ethylene and an unsaturated dicarboxylic acid anhydride or a multicomponent copolymer of these and an unsaturated dicarboxylic acid ester and / or vinyl ester is hydrolyzed and The dicarboxylic acid anhydride unit of these copolymers can be converted into a dicarboxylic acid unit or a half ester unit by modifying with / or alcohol. In the present invention, the ethylene-based copolymer (A) obtained by replacing a part or all of the unsaturated dicarboxylic acid anhydride units of the copolymer or multicomponent copolymer with a dicarboxylic acid unit or a half ester unit is also used. Can be used as desired.

To carry out hydrolysis, the ethylene-based copolymer (A) is dissolved in an organic solvent (for example, toluene) that dissolves the copolymer in the presence of a catalyst (for example, a tertiary amine).
It can be obtained by reacting with water at a temperature of 80 to 100 ° C. for 0.5 to 10 hours (preferably 2 to 6 hours, preferably 3 to 6 hours) and then neutralizing with an acid.

In order to carry out the alcohol modification, the ethylene copolymer (A) can be obtained by a solution method or a kneading method described later.

The solution method is similar to the case of hydrolysis in the presence or absence of the above catalyst in an organic solvent (the reaction is slow in the absence)
The reflux temperature of the alcohol used in 2 minutes to 5 hours (desirably 2 minutes to 2 hours, preferably 15 minutes to 1)
Time) is a method of reacting.

On the other hand, the kneading method is usually 0.01 to 1.0 parts by weight (preferably 0.05 to 100 parts by weight) based on 100 parts by weight of the ethylene copolymer (A).
0.5 part by weight) of the tertiary amine and the dicarboxylic acid unit in the copolymer are generally added in an amount of 0.1 to 3.0 times mol (preferably 1.0 to 2.0 times mol) of the saturated alcohol in the ethylene copolymer (A). ) Above the melting point of the alcohol used but below the boiling point of the alcohol used, using a kneader such as a Banbury mixer or extruder, which is commonly used in the field of rubber and synthetic resins, for several minutes to several tens of minutes (desirably ,
This is a method of reacting while kneading.

The saturated alcohol used in the above modification with alcohol is a linear or branched saturated alcohol having 1 to 12 carbon atoms, and examples thereof include methyl alcohol, ethyl alcohol and primary butyl alcohol.

In both cases of hydrolysis and modification with alcohol, the conversion rate to dicarboxylic acid and the half esterification rate are both 0.5 to 100%, preferably 10.0 to 100%.

The ethylene unit in this ethylene copolymer (A) is 30 ~
99.5% by weight, preferably 30 to 99.0% by weight, especially 35
-99.0% by weight is preferred. Further, the ratio of the unsaturated dicarboxylic acid unit, the anhydride unit and the half ester unit in the copolymer is 0.1 to 70 as the total amount thereof.
% By weight, preferably 0.5-70% by weight, especially 0.5
-60% by weight is preferred. When an ethylene-based copolymer having a copolymerization ratio of the dicarboxylic acid ester and / or vinyl ester in the ethylene-based copolymer (A) of more than 70% by weight is used, the softening point of the copolymer is high. In addition, it is not desirable because the fluidity is impaired at a temperature of 150 ° C. or less, and it is not economically preferable.

(B) Ethylene Copolymer (B) The ethylene copolymer (B) used in the present invention is composed of at least an ethylene unit and an "unsaturated hydroxyl unit [hereinafter referred to as" second component (B) "]. Is an ethylene-based copolymer containing 30 to 99.5% by weight of the ethylene unit.

This ethylene-based copolymer (B) is a copolymer that can be obtained by copolymerizing at least ethylene with the following monomer to form the second component (B), and a multi-component system of these and other monomers. Examples thereof include saponified products obtained by saponifying a copolymer and a copolymer of ethylene and a vinyl ester (in particular, vinyl acetate).

Examples of this monomer include hydroxyalkyl (meth) acrylate (wherein the alkyl group usually has 1 to 25 carbon atoms) and α-alkenyl alcohol having 3 to 25 carbon atoms.

A typical example of the monomer is hydroxymethyl (meth).
Mention may be made of acrylates, hydroxymethyl (meth) acrylates, hydroxypropyl (meth) acrylates, hydroxybutyl (meth) acrylates, hydroxyhexyl (meth) acrylates and allyl alcohols.

Further, examples of the other monomer include the unsaturated carboxylic acid ester and vinyl ester.

The ethylene unit in this ethylene copolymer (B) is 30 to
It is 99.5% by weight, preferably 30 to 99.0% by weight, and particularly preferably 35 to 99.0% by weight. The proportion of unsaturated hydroxyl units in the copolymer is 0.1 to 70% by weight, preferably 0.5 to 70% by weight, and particularly 0.5 to 0.5% by weight for the same reason as in the case of the ethylene copolymer (A). -60% by weight is preferred. Further, when using the multi-component copolymer containing the unsaturated carboxylic acid ester and / or vinyl ester, the total amount thereof is generally at most 70 wt% for the same reason as in the case of the ethylene copolymer (A). %
It is especially desirable that the amount be 60% by weight or less.

(C) Ethylene Copolymer (C) Further, the ethylene copolymer (C) used in the present invention is at least one unit selected from the group consisting of at least ethylene units and unsaturated epoxy units. The second component (C)], containing 30 to 99.5% by weight of ethylene units.

This ethylene-based copolymer (C) is a copolymer that can be obtained by copolymerizing at least ethylene with the following monomer to form the second component (C), and a multi-component system of these and other monomers. Examples thereof include saponified products obtained by saponifying a copolymer and a copolymer of ethylene and a vinyl ester (in particular, vinyl acetate).

Examples of this monomer include glycidyl alkyl (meth) acrylates represented by the following general formulas [(I) and (II)].

(Here, R ₁ is a hydrogen atom or a methyl group, and R ₂ has 1 carbon atom.
To 12 linear or branched alkylene groups and R ₃ is a vinyl group, an allyl group or a methacryl group) (I) and (II) A typical example of the monomer represented by the formula is butenetricarboxylic acid mono Glycidyl ester,
Glycidyl methacrylate, glycidyl acrylate, glycidyl ethacrylate, itaconic acid glycidyl ester, glycidyl methacrylate, 7,8-epoxy-1-octyl methacrylate, acrylic glycidyl ether, 7,8-epoxy-1-octyl vinyl ether, vinyl glycidyl ether , Allyl glycidyl ether and methallyl glycidyl ether.

Further, examples of the other monomer include the unsaturated carboxylic acid ester and vinyl ester.

The ethylene unit in this ethylene-based copolymer (C) is 30-
It is 99.5% by weight, preferably 30 to 99.0% by weight, and particularly preferably 35 to 99.0% by weight. The proportion of unsaturated epoxy units in the copolymer is 0.1 to 70% by weight, preferably 0.5 to 70% by weight, and particularly 0.5 to 0.5% by weight for the same reason as in the case of the ethylene copolymer (A). -60% by weight is preferred. Further, when using the multi-component copolymer containing the unsaturated carboxylic acid ester and / or vinyl ester, the total amount thereof is generally at most 70 wt% for the same reason as in the case of the ethylene copolymer (A). %, And particularly preferably 60% by weight or less.

Melt index of the ethylene-based copolymer (A), the ethylene-based copolymer (B) and the ethylene-based copolymer (C) (measured according to JIS K-7210 under the condition 4, hereinafter referred to as "MI") Is generally 0.001 to 1000 g / 10 minutes, preferably 0.05 to 500 g / 10 minutes, particularly preferably 0.1 to 500 g / 10 minutes. When these ethylene-based copolymers having an MI of less than 0.01 g / 10 min are used, it is difficult to mix these copolymers uniformly, and the moldability is not good.

Of these ethylene-based copolymers, when produced by a copolymerization method, it is usually 1 to 1 under high pressure of 500 to 2500 Kg / cm ^2.
Ethylene and the second component (A), the second component (B) or the second component (C) or these and other in the presence of a fast chain transfer agent (for example, an organic peroxide) at a temperature of 20 to 260 ° C. It can be obtained by copolymerizing with components, and the production method thereof is well known. Further, the method of producing the ethylene-based copolymer (A) by hydrolysis and / or modification with an alcohol and the method of producing the ethylene-based copolymer (B) by the saponification method are well known methods. is there.

(D) Carbon Black The carbon black used in the present invention generally has a specific surface area of low temperature nitrogen adsorption method and BE.
20-1800 m ² / g measured by T method and pore volume 3
1.5-4 measured by mercury porosimetry in the range of 0-7500Å.
It is 0 cc / g, and the one having a specific surface area of 600 to 1200 m ² / g is particularly effective.

Examples of the carbon black include channel black, thermal black, acetylene black, and carbon black produced by the furnace black method. About these carbon blacks, "Carbon Black Handbook" edited by the Carbon Black Association (book publisher, published in 1972), "Handbook edited by Rubber Digest",
Its production method and physical properties are well known from "Rubber / Plastic Compounded Chemicals" (Rubber Digest, published in 1974), "Synthetic Rubber Handbook", etc. Among these carbon blacks, conductive Carbon black and acetylene black obtained by the acetylene method (generally, the specific surface area is
600 to 1200 m ² / g) is not suitable because it has high conductivity and high modulus. Therefore, the channel black obtained by the channel method (generally, a specific surface area of 50
~ 1200 m ² / g), thermal black, thermal black obtained by furnace method and furnace black are preferred.

(E) Rubber Further, the rubber used in the present invention is industrially produced and used in various fields. Mooney viscosity (ML _{1 + 4} , 100 ℃) is 160 or less, 5 to 160
Those of 5 to 140 are particularly preferable.
Among the rubbers, acrylic rubber is a rubber containing acrylic acid ester as a main component, and usually contains 10 to 30% by weight of acrylonitrile as a copolymerization component. The Mooney viscosity of this rubber is usually 10-80. Further, isoprene-isobutene copolymer rubber is generally called butyl rubber, and isoprene and a small amount of isoprene (generally 10
(% By weight or less), and the Mooney viscosity is generally 10 to 80. Further, isobutylene rubber is a rubber whose main component is isobutylene, and its Mooney viscosity is usually 10 to 80. The content (copolymerization ratio) of acrylonitrile in the acrylonitrile-butadiene copolymer rubber is generally 10 to 50% by weight, and particularly preferably 15 to 50% by weight. The Mooney viscosity of this rubber is usually
10 to 100. In addition, the water additive of this rubber is partially reduced by hydrogenating the double bonds of this rubber. Moreover, silicone rubber is made of diorgano.
A straight-chain polymer of polysiloxane, which has as an organo group an alkyl group having at most 12 carbon atoms (for example, a methyl group) and an aryl group (for example, a phenyl group), a vinyl group, and the alkyl and allyl groups. A part of is substituted with a halogen atom (for example, a fluorine atom) and a nitrile group. The Mooney viscosity of this rubber is generally 5-60.

These rubbers are well known for their manufacturing method, physical properties, etc., by "Synthetic Rubber Handbook" (published by Asakura Shoten Co., Ltd.) by Kambara et al. Of these rubbers, isobutylene rubber and silicone rubber are preferable.

(F) Organic Peroxide The organic peroxide used in the present invention is not particularly limited, but it is preferable that the decomposition temperature (the temperature at which the half-life is 1 minute) be 130 ° C. or higher, especially 140 ° C. A temperature of at least ° C is suitable. Representative examples of suitable organic peroxides include ketone peroxides such as 1,1-bis-tertiary-butylperoxy-3,3,5-trimethylcyclohexane,
Hydroperoxides such as 2,5-dimethylhexane-2; 5-dihydroperoxide, 2,5-dimethyl-2,5-
Mention may be made of peroxyesters such as di-tertiary-butylperoxyhexane, diacyl peroxides such as benzoyl peroxide and dialkyl peroxides such as dicumyl peroxide.

Further, a polyfunctional substance such as triallyl isocyanurate and triallyl isocyanurate, which are used as a crosslinking aid in a usual rubber field, may be blended.

(G) Production of Mixture (1) Mixing Ratio In producing the mixture of the present invention, the ethylene-based copolymer (A), the ethylene-based copolymer (B) and the ethylene-based copolymer (G The mixing ratio of the ethylene-based copolymer (A) to the total amount (total) of
99% by weight [that is, the mixing ratio of ethylene-based copolymer (B) and ethylene-based copolymer (C) is 99 to 1% by weight], preferably 5 to 95% by weight, and more preferably 10 to 90% by weight.
Is preferred. The mixing ratio of the ethylene-based copolymer (A) in the total amount of the ethylene-based copolymer (A), the ethylene-based copolymer (B) and the ethylene-based copolymer (C) is 1
If it is less than 99% by weight or more than 99% by weight, the crosslinking is insufficient when the mixture is crosslinked by the method described below, and the adhesion to the electrolytic capacitor described below is not good.

Furthermore, the mixing ratio of the ethylene-based copolymer (C) in the total amount of the ethylene-based copolymer (B) and the ethylene-based copolymer (C) is 10 to 80% by weight [that is, the ethylene-based copolymer (C)). The mixing ratio of the polymer (B) is 90 to 20% by weight],
15 to 80% by weight is preferable, and 25 to 75% by weight is particularly preferable. Whether the mixing ratio of the ethylene-based copolymer (C) in the total amount of the ethylene-based copolymer (B) and the ethylene-based copolymer (C) is less than the lower limit or exceeds the upper limit, either Also, the obtained electrolytic capacitor encapsulant has poor heat resistance and may be deformed at 350 ° C., for example.

In addition, carbon black, rubber, organic peroxide, and a crosslinking aid based on 100 parts by weight of the total amount of the ethylene copolymer (A), the ethylene copolymer (B), and the ethylene copolymer (C) (use) The mixing ratio in the case of) is as follows.

The mixing ratio of carbon black is 1.0 to 120 parts by weight,
5.0 to 120 parts by weight is preferable, and 10 to 110 parts by weight is particularly preferable. If the mixing ratio of carbon black is less than 1.0 part by weight, a capacitor encapsulant having excellent mechanical strength and compression set cannot be obtained. On the other hand, when it exceeds 120 parts by weight, not only the mechanical strength is remarkably lowered, but also the crosslinking efficiency is deteriorated.

Further, the mixing ratio of rubber is 0.1 to 50 parts by weight, and 0.5 to
50 parts by weight is preferable, and 1.0 to 50 parts by weight is particularly preferable. If the rubber content is less than 0.1 part by weight, a flexible and highly elastic encapsulant for electrolytic capacitors cannot be obtained. On the other hand, if it exceeds 50 parts by weight, a highly elastic sealing material for electrolytic capacitors can be obtained, but the heat resistance and the resistance to solder are poor.

The mixing ratio of the organic peroxide is 0.1 to 10 parts by weight, preferably 0.5 to 10 parts by weight, and particularly preferably 0.5 to 8 parts by weight. Furthermore, when a crosslinking aid is used, its proportion is at most 10 parts by weight. If the mixing ratio of the organic peroxide is less than the lower limit, the crosslinking of the rubber does not proceed completely, so that a good sealing material for the electrolytic capacitor cannot be obtained.
On the other hand, when the content exceeds the upper limit, on the contrary, crosslinking is fast,
Not only is it difficult to obtain a sealing material for an electrolytic capacitor having a good shape due to the rapid progress of crosslinking,
Controlling the crosslinking can be difficult.

(2) Mixing method To produce this mixture, the ethylene-based copolymer (A),
The ethylene copolymer (B), the ethylene copolymer (C), the carbon black, the rubber and the organic peroxide may be uniformly mixed. As a mixing method, dry blending may be performed using a mixer such as a Henschel mixer which is generally performed in the field of olefin polymers, and a method of melt kneading using a mixer such as Banbury, an extruder and a roll mill is used. can give. At this time, a more uniform mixture can be obtained by previously dry blending and melt-kneading the resulting mixture. When melt-kneading, it is necessary that the ethylene-based copolymer (A), the ethylene-based copolymer (B) and the ethylene-based copolymer (C) do not substantially undergo a crosslinking reaction. (1) is not preferable because it not only deteriorates the moldability during the molding process as described later, but also causes the target shape of the molded product and the heat resistance when the molded product is crosslinked). From this, the temperature of melt-kneading depends on the type and viscosity of the ethylene polymer used, but it may be room temperature (20 ° C) or
150 ° C is desirable and 140 ° C or less is suitable.

As a measure of this "substantially not cross-linking", "the ethylene-based copolymer (A), the ethylene-based copolymer (B) and the ethylene-based copolymer (C) are mixed in boiling toluene with 3
After the time extraction treatment, the residue having a diameter of 0.1 micron or less "(hereinafter referred to as" extraction residue ") is generally preferably 15% by weight or less, and preferably 10% by weight or less,
The optimum amount is 5% by weight or less.

(H) Sealing of Electrolytic Capacitor To seal an electrolytic capacitor using the mixture obtained as described above, injection molding method, stamping generally performed in the field of thermoplastic resin or thermosetting resin is used. It can be achieved by applying a molding method, a press molding method, a dipping method, an injection method, a low pressure transfer method, or the like. At this time, it is important to mold at a temperature at which the ethylene-based copolymer (A), the ethylene-based copolymer (B) and the ethylene-based copolymer (C) do not substantially crosslink. In the case of the present invention, the temperature of the mixture is preferably 250 ° C or lower, preferably 160 ° C or lower. But 8
Below 0 ° C, the mixture is not sufficiently melted, which is not preferable. The extraction residue of the mixture at this point is desirably 15% or less, preferably 10% by weight or less, and most preferably 5% by weight or less. For the purpose of sealing by the injection molding method, the low pressure transfer molding method, etc., from the above, the molten mixture can be obtained by press-fitting it into the mold in the temperature range of 80 to 160 ° C. The characteristic of the present invention is that the temperature at which the mixture crosslinks the integrally molded product (usually 120 to 280 ° C).
Is to hold for a certain period of time. 0.1 to 2 while holding
It is desirable to apply a slight pressure such as 0 kg / cm ² (gauge pressure). The higher the temperature is, the shorter the holding time is. Usually, it is preferably 10 seconds to 10 minutes at 200 ° C. or higher, and 1 minute to 30 minutes at 120 to 200 ° C. Further, in the case of the press molding method, for the same reason as above, a substantially non-crosslinking sheet material molded at 80 to 160 ° C. is preliminarily set to a temperature range of 160 ° C. to 280 ° C. with a mold of 1 to 40 kg / It is possible to manufacture an electrolytic capacitor which is sealed in a desired mold at the same time while pressing the mold with a pressure of cm ² (gauge pressure).

Further, as shown in FIG. 1, the lead wire is set in advance in the case, and the mixture is poured into a predetermined mold while being pressurized in a molten state, and further in a high temperature range (120 ° C to 280 ° C). It is also possible to crosslink while heating and adhering to the peripheral container and further to the lead wire.

The crosslinked product of the mixture in the electrolytic capacitor obtained as described above preferably has an extraction residue of 70% or more,
75% or more is suitable.

In the present invention, it is important to heat and pressurize in a temperature range of 120 to 280 ° C. in order to impart heat resistance to the mixture thus obtained in the electrolytic capacitor. In this temperature range, a crosslinking reaction occurs in the mixture,
Adhesiveness and heat resistance are remarkably improved. Furthermore, in order to obtain uniform adhesiveness, a method of applying pressure under a slight load, particularly under reduced pressure, may be performed.

A typical electrolytic capacitor of the present invention will be briefly described with reference to the drawings. FIG. 1 is a partially enlarged sectional view of this electrolytic capacitor. In this drawing, 1 is a case, and 2 is a sealing material of the present invention (sealing port, cross-linked product of mixture).
Is. Also, 3 is an electrolytic capacitor, which is made up of and lead wire terminals. The encapsulant may be molded in advance by 1 to 5% larger than a predetermined size, and after encapsulating in a case, the encapsulant may be heated and pressurized within the above temperature range to simultaneously bond the case and the lead wire together. . Further, the electrolytic solution or the like can be injected later through the sealing port.

Examples and Comparative Examples Hereinafter, the present invention will be described in more detail with reference to Examples.

In addition, in Examples and Comparative Examples, the peel strength was measured by the force with which the sealing material was pulled out from the case. The solder heat resistance of the sealing material was evaluated by floating for 20 seconds in a solder bath of lead / tin = 90/10 (weight ratio) held at 360 ° C. Further, the compression set was based on JIS K6301, and the amount of strain after aging at a temperature of 150 ° C. for 70 hours was measured. Further, as the mechanical strength, the tearability test complied with JIS K6301 and was measured using a JIS B type dumbbell.

A mixture of the ethylene copolymer (A), the ethylene copolymer (B), the ethylene copolymer (C) and the carbon black (C) used in Examples and Comparative Examples is shown below.

Terpolymer of 79 mol% ethylene, 19.5 mol% methylmethacrylate and 1.5 mol% maleic anhydride maleic anhydride [MI 220 g / 10 minutes, hereinafter referred to as "copolymer (1)"], ethylene-vinyl acetate Saponification product obtained by saponifying a copolymer [vinyl acetate copolymerization ratio 28% by weight] [saponification degree 97.5%, MI 75 g / 10 minutes, density 0.951 g
/ cm ³ , hereinafter referred to as "copolymer (2)"] and terpolymer of ethylene-methyl methacrylate-glycidyl methacrylate [copolymerization ratio of methyl methacrylate 1
8.8% by weight, glycidyl methacrylate copolymerization ratio 12.
7% by weight, hereinafter referred to as "copolymer (3)"] was dry blended for 5 minutes using a tumbler at a ratio shown in Table 1 for each blending amount. Single-screw extruder (diameter 50 mm) at each cylinder temperature (C ₁ 100 ℃, C ₂ 100 ℃) and die temperature 120 ℃
Kneading was carried out while melting using.

Examples 1 to 14 and Comparative Examples 1 to 10 Carbon black based on 100 parts by weight of the mixture (I) to (V) and the copolymer (1) to the copolymer (3) obtained as described above, respectively. As carbon black (Asahi Carbon Co., Ltd., trade name Asahi Thermal, average particle size 11
8 millimicron, specific surface area 19 m ² / g, SRF, hereafter referred to as “CB”), and rubber as polyisobutylene [Moonie viscosity (ML _{1 + 4} ) 45, hereafter referred to as “PBR”], Mooney viscosity
Hydrogen of isoprene-isobutylene copolymer rubber having a 45 (hereinafter referred to as "IIR"), silicone rubber having a Mooney viscosity of 10 (hereinafter referred to as "SiR") or hydrogen of an acrylonitrile-butadiene copolymer rubber having a Mooney viscosity of 60. An additive (hereinafter referred to as "ZNBR") is used, and further 2,5-dimethyl-2,5-ditertiary butylperoxy hexene (hereinafter referred to as "PO" as an organic peroxide) Allyl isocyanurate (hereinafter referred to as "TAIC" as a crosslinking aid)
Using open rolls with the composition ratio (polymerization part) shown in Table 2 set to 80 ° C in advance
The sheet was molded while sufficiently kneading for 20 minutes. After making the sheet, each pellet was made using a sheet cutter.

Each mixture and rubber obtained as described above is
Extruder equipped with a die (diameter 40 mm, die width 30 cm, rotation speed 85
A film having a cylinder temperature (C ₁ and C ₂ ) and a die temperature of 120 ° C. and a thickness of 100 μm was formed by using rotation / minute. The extrusion residue of the obtained film was measured. In all cases, it was 0%.

Each of the sheets thus obtained was subjected to a pressure of 20 kg / cm ² (gauge pressure) for 10 minutes at a temperature shown in Table 3 for a cylindrical shape having a diameter of 10 mm and a height of 5 mm. A sealed product was manufactured.

Furthermore, the compression set test was conducted at a temperature shown in Table 3 for 15 minutes each using a heat press machine at 200 Kg / cm ² (gauge pressure).
A sample according to JIS K6301 was manufactured under pressure. Also,
The tearability test was conducted under the same conditions as above for the sheet (thickness 2 mm)
Was manufactured.

In addition, the case shown in FIG. 1 (made of aluminum, inner diameter
The cylindrical sealing material was inserted into the inlet of 10 mm, depth 30 mm, and aluminum thickness 0.5 mm), and the periphery was heated to 240 ° C. to perform sealing, to manufacture an electrolytic capacitor.

Example 21, Comparative Example 8 A cylindrical plug having a diameter of 5 mm and a height of 3 mm was cut out from each sheet used in Example 1 and Comparative Example 4, and the diameter was 5 m.
It was heated to 300 ° C. and inserted into the inlet of a cylindrical aluminum container having m, an inner diameter of 1 mm and a height of 15 mm, as shown in FIG. After cooling, it was taken out.

Solder heat resistance of each cylindrical encapsulant obtained as described above and the stress when the encapsulant was pulled out from the electrolytic capacitor through the screw inserted at a right angle at a pulling speed of 50 mm / min, and each electrolytic capacitor The extraction residue of the crosslinked product of the mixture was measured. They are shown in Table 3. In the column of "Solder heat resistance" in this table, "○" means that no deformation was observed, and "X" means that it was melted and the prototype was not retained.

From the results of the above Examples and Comparative Examples, the ethylene-based copolymer (A), the ethylene-based copolymer (B), the ethylene-based copolymer (C), and the carbon black used in the production of the electrolytic capacitor of the present invention were used. The crosslinked product of the mixture of (D), rubber (E) and organic peroxide (F) has not only excellent solder heat resistance, but also strong adhesion to the case and resistance to strain. Because it is excellent, it is cheaper than encapsulation that uses thermosetting resin such as epoxy resin that is usually used, it can be easily manufactured, and there is obtained a product without the conventional defects. It is obvious that

EFFECTS OF THE INVENTION The electrolytic capacitor of the present invention and the crosslinked product of the mixture used for the production thereof exhibit the following effects (features) including the production process thereof.

(1) Adhesion to the cocodencer case is excellent, so there is little evaporation of electrolyte and entry of impurities such as water,
Therefore, the electrical characteristics of the electrolytic capacitor do not deteriorate,
It can be used in a stable state for a long time.

(2) Since it has good solvent resistance, it can be washed with a solvent such as trichlene and freon.

(3) Since it has excellent flexibility and heat resistance, it has good thermal shock resistance and shock resistance.

(4) Sealing and sealing can be performed at the same time, which is advantageous in terms of cost.

(5) Solder heat resistance is extremely excellent (it can withstand even 360 ° C), so it is possible to solder the lead wires directly during mounting.

[Brief description of drawings]

FIG. 1 is a partially enlarged sectional view of the electrolytic capacitor of the present invention. 1 ... Case 2 ... Sealing material (sealing port, cross-linked product of mixture) 3 ... Electrolytic capacitor

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C08L 23/22 LCZ 29/02 LGT 33/04 LJD 35/00 LHR 83/04 LRY H01G 9/10 // (C08K 5/00 3:04 5:14)

Claims (1)

[Claims] 1. A method comprising: (A) at least ethylene and at least one unit selected from the group consisting of unsaturated dicarboxylic acid units, their anhydride units and half ester units, and having an ethylene unit content of 30 to 99.5. Ethylene copolymers (A) and (B), which are in weight percent, are composed of at least ethylene units and unsaturated hydroxyl units, and the ethylene unit content is 30 to 99.5 weight percent (B). , (C) is composed of at least ethylene units and unsaturated epoxy units, and the content of ethylene units is
30 to 99.5% by weight of ethylene copolymer (C),
At least one Mooney viscosity selected from the group consisting of (D) carbon black, (E) acrylic rubber, isoprene-isobutene copolymer rubber, isobutylene rubber, hydrogenated copolymer rubber of acrylonitrile and butadiene, and silicone rubber ( ML _{1 + 4} , 100 ° C) is a mixture of rubber and (F) an organic peroxide having a temperature of 160 or less, and the ethylene-based copolymer (A) is contained in the total amount of these ethylene-based copolymers. The mixing ratio is 1 to 99% by weight, and the mixing ratio of the ethylene copolymer (C) in the total amount of the ethylene copolymer (B) and the ethylene copolymer (C) is 1 to 80%. % By weight, and the mixing ratio with respect to 100 parts by weight of the total amount of these ethylene-based copolymers is 1.0 to 120 parts by weight in carbon black,
And 0.1 to 50 parts by weight for rubber, and 0.1 to 10 parts by weight for organic peroxide, electrolysis sealed by a mixture having cross-linked products of ethylene-based copolymers in a mixture. condenser.