JPH0673342B2 - 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 two ethylene-based copolymers and a rubber crosslinked product and carbon black. More specifically, (A) an ethylene copolymer having at least an ethylene unit and at least one unit selected from the group consisting of a carboxylic acid unit, a dicarboxylic acid unit, an anhydride unit thereof and a half ester unit thereof, (B) Ethylene copolymer having at least ethylene unit and at least one unit selected from the group consisting of hydroxyl unit, amino unit and glycidyl unit, (C) carbon black, (D) acrylic rubber, isoprene-isobutene copolymer rubber, At least one Mooney viscosity (ML _{1 + 4} , 100 ° C) selected from the group consisting of isobutylene rubber, hydrogenated products of copolymerized rubber of acrylonitrile and butadiene, and silicone rubber, and (E) organic Mutuality of Ethylene Copolymers in Mixtures of Peroxides In addition, the present invention relates to an electrolytic capacitor sealed with a mixture having a crosslinked product of rubber, which has sufficient resistance to an electrolytic solution and heat resistance sufficient to withstand solder as well as crosslinking. It is an object of the present invention to provide an electrolytic capacitor which is relatively simple and which is sealed with a synthetic resin which is excellent in adhesiveness to a case and a lead wire.

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 jelly-like liquid for 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 high hardness was obtained. Further, a highly elastic material was not obtained, and there was a problem in terms of flexibility and the like.

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, Crosslinkable in a short time, not only resistant enough to electrolytic solution, but also heat resistant enough to withstand solder, and also excellent adhesion to case and lead wire. The purpose is to obtain an electrolytic capacitor sealed with resin.

Means and Actions for Solving Problems According to the present invention, these problems are (A) “consisting of at least ethylene unit and carboxylic acid unit, dicarboxylic acid unit, anhydride unit thereof and half ester unit thereof. An ethylene copolymer comprising at least one unit selected from the group and having an ethylene unit content of 30 to 99.5% by weight [hereinafter referred to as "ethylene copolymer (A)"], ( B) "Containing at least ethylene units and at least one unit selected from the group consisting of hydroxyl units, amino units and glycidyl units, and having an ethylene unit content of 30 to 99.5% by weight.
Is an ethylene-based copolymer "[hereinafter referred to as" ethylene-based copolymer (B) "], (C) carbon black, (D)
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.
A mixture of (E) an organic peroxide and a rubber having a temperature of 00 ° C) of 160 or less, and the mixing ratio of any one of the ethylene-based copolymers in the total amount of these ethylene-based copolymers is 1 to 99% 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 120 parts by weight for carbon black, and 0.1 to 50 parts by weight for rubber, and In organic peroxide
An electrolytic capacitor which is encapsulated by a mixture having 0.1 to 10 parts by weight of ethylene-based copolymers in the mixture and cross-linked rubber.

Can be solved by. Hereinafter, the present invention will be specifically described.

(A) Ethylene-based copolymer (A) The ethylene-based copolymer (A) used in the present invention is at least an ethylene unit and a group consisting of "carboxylic acid unit, dicarboxylic acid unit, anhydride unit thereof and half ester unit thereof". And an ethylene-based copolymer containing at least one unit selected from the following [hereinafter referred to as "second component (A)"] and containing 30 to 99.5% by weight of the ethylene unit.

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 unsaturated monocarboxylic acids having at most 25 carbon atoms such as acrylic acid, methacrylic acid and ethacrylic acid, and maleic anhydride, tetrahydrophthalic anhydride, maleo-pimaric anhydride, 4-methylcyclohexane. Unsaturated dicarboxylic acids having 4 to 50 carbon atoms such as -4-ene-1,2-carboxylic anhydride and bicyclo (2,2,1) -hepta-5-ene-2,3-dicarboxylic anhydride Anhydrous is mentioned.

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 more) 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. The proportion of the carboxylic acid unit, the anhydride unit and the half ester unit in the copolymer is 0.1 to 70% by weight as their total amount, preferably 0.5 to 70% by weight, and particularly 0.5 to 60% by weight. % Is preferred. If an ethylene-based copolymer having a proportion of carboxylic acid units, anhydride units and half ester units in the ethylene-based copolymer (A) of less than 0.1% by weight is used, the ethylene-based copolymer described below is used. When it is crosslinked by heating with (B), not only is the crosslinking incomplete, but the adhesion with the metal layer is not good. On the other hand, even if it exceeds 70% by weight, the characteristics of the present invention will be exhibited, but it is not necessary to exceed 70% by weight, which is not preferable in terms of production and economy.

When a multi-component copolymer containing the unsaturated carboxylic acid ester and / or vinyl ester is used, the total amount thereof is usually at most 70% by weight, preferably 60% by weight or less. When an ethylene-based copolymer having a copolymerization ratio of unsaturated dicarboxylic acid ester and / or vinyl ester of more than 70% by weight is used, the softening point of the copolymer becomes high, and the fluidity at a temperature of 150 ° C. or lower becomes low. Not only is it undesirable because it is damaged, but it is also not economically desirable.

(B) Ethylene Copolymer (B) The ethylene copolymer (B) used in the present invention is at least one ethylene unit and at least one selected from the group consisting of a hydroxyl unit, an amino unit and a glycidyl unit. Unit "(hereinafter referred to as" second component (B) "), and its ethylene unit is 30 to 9
It is an ethylene-based copolymer containing 9.5% by weight.

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 glycidyl alkyl (meth) acrylates and hydroxyalkyl (meth) acrylates represented by the following general formula (where the carbon number of the alkyl group is usually 1
.About.25), .alpha.-alkenyl alcohols having 3 to 25 carbon atoms, .alpha.-amines having 2 to 25 carbon atoms, and primary or secondary aminoalkyl (meth) acrylates (the alkyl group usually has 1 carbon atom). ~ 25).

(Wherein R ₁ is H or a methyl group, and R ₂ is a linear or branched alkyl group having 1 to 12 carbon atoms) Typical examples of this monomer include butenetricarboxylic acid monoglycidyl ester and glycidyl methacrylate. , Glycidyl acrylate, glycidyl ethacrylate, itaconic acid glycidyl ester, hydroxymethyl (meth) acrylate, hydroxymethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, hydroxyhexyl (meth)
Acrylate, allyl alcohol, allyl (a
llyl) amine and aminoethyl (meth) acrylate.

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 hydroxyl units, amino units and glycidyl units in the copolymer is 0.1 to 70% by weight for the same reason as in the case of the ethylene copolymer (A), and 0.5 to 70% by weight. Particularly preferred is 0.5 to 60% by weight. 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). %, Especially 60% by weight
The following is desirable.

The melt index (measured under condition 4 according to JIS K-7210, hereinafter referred to as “MI”) of the ethylene copolymer (A) and the ethylene copolymer (B) is generally 0.
001 to 1000 g / 10 minutes, preferably 0.05 to 500 g / 10 minutes,
Particularly preferred is 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.

Among 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.
Copolymerizing ethylene with the second component (A) or the second component (B) or with these other components 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 the method described above and the manufacturing 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.

(C) 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 and thermal black obtained by furnace method and furnace black are preferable.

(D) 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 of acrylonitrile (copolymerization ratio) of the acrylonitrile-butadiene copolymer rubber is generally 10 to 50% by weight, and particularly 15 to 50% by weight.
Weight% is desirable. The Mooney viscosity of this rubber is usually 10-100. In addition, the water additive of this rubber is partially reduced by hydrogenating the double bonds of this rubber. Moreover, silicone rubber is a linear polymer of diorganopolysiloxane, which has an alkyl group having at most 12 carbon atoms as an organo group (for example, a methyl group) and an allyl group (for example, a phenyl group), Examples thereof include vinyl groups and some of the alkyl and allyl groups substituted with halogen atoms (for example, fluorine atoms) and nitrile groups. 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.

(E) Organic Peroxide The organic peroxide used in the present invention is not particularly limited, but is preferably one having a decomposition temperature (temperature at which the half-life is 1 minute) of 130 ° C. or higher, and particularly, A temperature of 140 ° C or higher is preferable. A typical example of a suitable organic peroxide is 1,1-bis-tertiary-butylperoxy-3,3,5-
Ketone peroxide such as trimethylcyclohexane, hydroperoxide such as 2,5-dimethylhexane-2; 5-dihydroperoxide, 2,5-dimethyl-
Peroxyesters such as 2,5-di-tertiary-butylperoxyhexane, diacyl peroxides such as benzoyl peroxide and dialkyl peroxides such as dicumyl peroxide are mentioned.

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.

(F) Production of Mixture (1) Mixing Ratio In producing the mixture of the present invention, the total amount (total) of the ethylene-based copolymer (A) and the ethylene-based copolymer (B) in the obtained mixture is occupied. The mixing ratio of the ethylene-based copolymer (A) is 1 to 99% by weight [that is, the mixing ratio of the ethylene-based copolymer (B) is 99 to 1% by weight].
95% by weight is desirable and 10 to 90% by weight is especially preferred. A mixture of the ethylene-based copolymer (A) and the ethylene-based copolymer (B) which is contained in the total amount of the ethylene-based copolymer (A) and the ethylene-based copolymer (B) is less than 1% by weight or more than 99% by weight. When the compound is crosslinked by the method described below, the crosslinking is insufficient and, for example, the adhesion to the electrolytic capacitor described below is not good.

The mixing ratio of carbon black to the total amount (total) of 100 parts by weight of the ethylene copolymer (A) and the ethylene copolymer (B) 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. When the blending ratio of carbon black is less than 1.0 part by weight based on 100 parts by weight of the total amount of the ethylene copolymer (A) and the ethylene copolymer (B), sealing of a capacitor excellent in mechanical strength and compression set is achieved. Can't get a stop. 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 the rubber is 0.1 to 50 parts by weight, preferably 0.5 to 50 parts by weight, based on 100 parts by weight of the total amount (total) of the ethylene copolymer (A) and the ethylene copolymer (B). In particular, 1.0 to 50 parts by weight is suitable. Total amount of ethylene-based copolymer (A) and ethylene-based copolymer (B) 10
When the compounding ratio of rubber to 0 part by weight 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 more preferably 0.5 to 8 parts by weight. Furthermore, when a crosslinking aid is used, its proportion is at most 10 parts by weight. When the mixing ratio of the organic peroxide to the ethylene copolymer (A) and the ethylene copolymer (B) is less than the lower limit, the crosslinking of the rubber does not proceed completely, so that a good sealing material for electrolytic capacitors can be obtained. I can't. On the other hand, when the content exceeds the upper limit, on the contrary, it is difficult to obtain a sealing material for an electrolytic capacitor having a good shape because the crosslinking is fast and the crosslinking proceeds rapidly, and it is necessary to control the crosslinking. Can be difficult.

(2) Mixing method To produce this mixture, the ethylene-based copolymer (A),
The ethylene copolymer (B), carbon black, rubber and organic peroxide may be mixed uniformly. 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,
Ethylene-based copolymer (A) and ethylene-based copolymer (B)
It is necessary that and do not substantially crosslink (when crosslinked, not only the moldability deteriorates when the resulting mixture is molded and processed as described below, but also the desired shape and shape of the molded product are obtained. It is not preferable because it causes a decrease in heat resistance when cross-linked). From this, the temperature of melt kneading depends on the type and viscosity of the ethylene copolymer used, but it may range from room temperature (20 ℃) to 150 ℃.
Is preferable and 140 ° C. or lower is preferable.

As a measure of "substantially no cross-linking", "the ethylene-based copolymer (A) and the ethylene-based copolymer (B) are treated with a diameter of 0.
Generally, it is preferable that the "residue of 1 micron or more" (hereinafter referred to as "extraction residue") is 15% by weight or less,
Weight% or less is suitable, and 5 weight% or less is optimal.

(G) 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 are 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 copolymer (A) and the ethylene copolymer (B) 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. However, if the temperature is lower than 80 ° 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. Injection molding method,
From the above, the sealing by the low-pressure transfer molding method or the like can be obtained by press-fitting the molten mixture in the temperature range of 80 to 160 ° C. A feature of the present invention is that the integrally molded product is held at a temperature at which the mixture crosslinks (usually 120 to 280 ° C.) for a certain period of time. It is desirable to slightly pressurize, such as 0.1 to ²⁰ kg / cm ² (Geese pressure), while holding. The higher the temperature, the shorter the holding time.
At ˜200 ° C., 1 minute to 30 minutes is preferable. Further, in the case of the press molding method, for the same reason as above, the sheet material molded at 80 to 160 ° C. that is not substantially crosslinked is
1-40kg / with a mold set in the temperature range of ℃ to 280 ℃
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 encapsulant was evaluated by floating it in a solder bath of lead / tin = 90/10 (weight ratio) held at 300 ° C for 20 seconds. further,
Compression set according to JIS K6301, 70 at a temperature of 150 ℃
The amount of strain after aging 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) and the carbon black (C) used in the examples and comparative examples is shown below.

Ethylene copolymer (A), ethylene copolymer (B)
And a carbon black (C) mixture having an MI of 30
0 g / 10 min ethylene-acrylic acid copolymer (density 0.9
54g / cm ³ , acrylic acid copolymerization ratio 20% by weight, hereinafter "EAA"
Saponification product obtained by saponifying ethylene-vinyl acetate copolymer having a vinyl acetate copolymerization ratio of 28% by weight (saponification degree 97.5%, MI 75 g / 10 minutes, density 0.951 g / cm ³ , below). "Saponified product") (mixing ratio 50:50 (weight ratio), hereinafter referred to as "mixture (I)"), ethylene having MI of 200 g / 10 min.
A mixture of methacrylic acid copolymer (density 0.950 g / cm ³ , methacrylic acid copolymerization ratio 25% by weight) and the saponification degree [mixing ratio 50:50 (weight ratio), hereinafter referred to as “mixture (II)”] , MI is 212 g / 10 min, ethylene-ethyl acrylate-maleic anhydride terpolymer (ethyl acrylate copolymerization ratio 30.7 wt%, maleic anhydride copolymerization ratio 1.7 wt%) and MI 123 g / 10 min. Ethylene-methylmethacrylate-hydroxymethacrylate terpolymer (copolymerization ratio of methylmethacrylate 20.7% by weight, copolymerization ratio of hydroxymethacrylate 11.7% by weight) [mixing ratio 50:50 (weight ratio ), Hereinafter referred to as "mixture (III)"] and MI is 105 g / 10 minutes ethylene-methyl methacrylate-maleic anhydride terpolymer (copolymerization ratio of methyl methacrylate 20.5 wt%, Copolymerization ratio 3.1 wt%) and ethylene water maleate - methyl methacrylate - terpolymer of glycidyl methacrylate (copolymerization ratio of methyl methacrylate
18.6% by weight, glycidyl methacrylate copolymerization ratio 1
2.7% by weight) (mixing ratio 30:70 (weight ratio), hereinafter referred to as "mixture (IV)") was used. These mixtures were produced by dry blending the respective copolymers or terpolymers for 5 minutes using a Henschel mixer.

Mixtures (I) to (IV) obtained as described above,
Carbon black (made by Asahi Carbon Co., Ltd., trade name Asahi Thermal, average particle size 118 mm, specific surface area 19 m
² / g, SRF, referred to as "CB"), and polyisobutylene as rubber (Moonie viscosity (ML _{1 + 4} ) 45, hereinafter referred to as "PBR"), isoprene-isobutylene copolymer rubber having Mooney viscosity of 45 ( Hereinafter referred to as "IIR"), the Mooney viscosity is 1
Using a silicon rubber having a value of 0 (hereinafter referred to as "SiR") or a hydrogenated product of an acrylonitrile and a butadiene copolymer rubber having a Mooney viscosity of 60 (hereinafter referred to as "ZNBR"),
Furthermore, 2,5-dimethyl-2,5-ditertiary butylperoxy hexene (hereinafter referred to as "PO" as an organic peroxide), triallyl isocyanurate (hereinafter referred to as "TAIC" as a crosslinking aid) Each of the above) was sufficiently kneaded for 20 minutes using an open roll whose temperature was previously set to 80 ° C. at a blending ratio (parts by weight) shown in Table 2 to form a sheet. After forming the sheet, square pellets were formed 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 thickness of 100 μm was formed under the conditions where the cylinder temperature is shown in Table 1 by using the rotation speed / minute. The extraction residue of the obtained film was measured. In all cases, it was 0%.

Examples 1 to 20 and Comparative Examples 1 to 7 Each of the sheets thus obtained was subjected to a pressure of 20 kg / cm ² (gauge pressure) using a heat press machine at the temperature shown in Table 2 for 10 minutes. A columnar encapsulation having a diameter of 10 mm and a height of 5 mm was manufactured.

Furthermore, the compression set test was conducted at a temperature shown in Table 3 for 15 minutes 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 Each sheet used in Example 1 and Comparative Example 4 was cut into a columnar encapsulation having a diameter of 5 mm and a height of 3 mm, 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 stress when pulling out the encapsulant from the electrolytic capacitor through a 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 2. In addition, in the column of "Solder heat resistance" in this table, "○" means that no deformation was observed, and "X" means that the melt did not stop the prototype.

From the results of the above Examples and Comparative Examples, the ethylene copolymer (A), the ethylene copolymer (B), the carbon black (C), the rubber (D) and the rubber used in the production of the electrolytic capacitor of the present invention, and The cross-linked product of the mixture of organic peroxides is not only excellent in solder heat resistance, but also strong in adhesiveness to the case and excellent in resistance to strain, and thus is a commonly used epoxy resin. It is obvious that a resin that is cheaper than the sealing using a thermosetting resin such as the above, can be easily manufactured, and has the conventional drawbacks eliminated.

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 capacitor case is excellent, so there is little evaporation of electrolyte and infiltration 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 the solvent resistance is good, a detergent using a solvent such as trichlene and freon is also possible.

(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 Since the heat resistance is excellent, it is possible to directly solder the lead wires 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

Claims (1)

[Claims] 1. An ethylene unit and at least one unit selected from the group consisting of a carboxylic acid unit, a dicarboxylic acid unit, an anhydride unit thereof and a half ester unit, and the ethylene unit content is 30 to 99.5.
(B) at least one ethylene unit and at least one unit selected from the group consisting of hydroxyl units, amino units and glycidyl units, and having an ethylene unit content of 30 to 99.5% by weight.
A group consisting of a weight% of an ethylene copolymer, (C) carbon black, (D) acrylic rubber, isoprene-isobutene copolymer rubber, isobutylene rubber, a hydrogenated product of a copolymer rubber of acrylonitrile and butadiene, and silicone rubber. It is a mixture of at least one Mooney viscosity (ML _{1 + 4} , 100 ° C) of 160 or less selected from the above and (E) an organic peroxide, in the total amount of these ethylene-based copolymers. The mixing ratio of any of the ethylene-based copolymers is 1 to 99% 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 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.