JPH0666238B2 - Electrolytic capacitor- - Google Patents

Description

TECHNICAL FIELD The present invention not only has sufficient resistance to an electrolytic solution and heat resistance to withstand solder, but also has adhesiveness to a case and a lead wire. It is an object of the present invention to provide an electrolytic capacitor using a sealing material which is also excellent.

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 cylindrical type of about 0.05 cm ³ which is widely used mainly for transistor radios,
Even metal case type of about 0 cm ³ is used. In recent years, solid electrolytic capacitors have been downsized, and there has been developed a cylindrical type in which the electrodes are taken out from the sealing port using manganese dioxide, carbon, solder, etc. without using the 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.

Problems to be Solved by the Invention However, with these curable resins, not only the production efficiency is poor because the curing time is relatively long, but also the liquid leakage due to insufficient adhesion with the capacitor case. It is generated or immersed in the liquid of the cathode (for example, glycerine ethylene glycol, boric acid, ammonia, etc.), and because of its hygroscopic property, it absorbs moisture from the sealing port and the concentration of the internal electrolyte changes, shortening the life. I was letting it. 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.

Furthermore, when carbon black was not added, there were problems such as the most necessary compression permanent property for the sealing portion of the electrolytic capacitor and damage due to compression, that is, poor tearability.

From the above, the present invention does not have these drawbacks (problems), can be crosslinked in a short time, has excellent mechanical strength such as compression set, and has sufficient resistance to an electrolytic solution. Not only is there a need to obtain an electrolytic capacitor using a sealing material that has sufficient heat resistance to withstand solder and has excellent adhesion to the case and lead wires.

Means for Solving the Problems The present invention comprises (A) 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 Ethylene copolymer having an ethylene unit content of 30 to 99.5% by weight "[hereinafter referred to as" ethylene copolymer (A) ", (B)" from a group consisting of a hydroxyl unit, an amino unit and a glycidyl unit. An ethylene copolymer comprising at least one selected unit and an ethylene unit, and having an ethylene unit content of 30 to 99.5% by weight "(hereinafter referred to as" ethylene copolymer (B) ") and ( C) is a mixture of carbon black, and the mixing ratio of any of the ethylene-based copolymers in the total amount of these ethylene-based copolymers is 1 to 99% by weight. A mixing ratio of carbon black is 1.0 to 100 parts by weight with respect to a total amount of 100 parts by weight of a ethylene copolymer, and a crosslinked product obtained by crosslinking a mixture is used to provide an electrolytic capacitor.

Hereinafter, the present invention will be specifically described.

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

As the ethylene-based copolymer (A), a copolymer that can be obtained by copolymerizing ethylene with the following monomer that is the second component (A), and a multi-component copolymer of these and other monomers And those obtained by hydrolyzing and / or modifying the acid anhydride group in these copolymers.

As a typical example of the second component (A), acrylic acid, unsaturated monocarboxylic acid having at most 25 carbon atoms such as methacrylic acid and ethacrylic acid and maleic anhydride, tetrahydrophthalic anhydride, maleo-pimaric anhydride, 4-methylcyclohexane-4-ene-1,2-carboxylic acid anhydrides and bicyclo (2,2,1) -hepta-5-ene-2,3-dicarboxylic acid anhydrides having 4 to 50 carbon atoms An unsaturated dicarboxylic acid anhydride 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 less) carbon atoms. Examples include carboxylic acid esters and vinyl esters having at most 30 carbon atoms such as vinyl acetate and vinyl propionate.

Among the above ethylene-based copolymers (A), hydrolysis of a copolymer of ethylene and an unsaturated dicarboxylic acid anhydride or a multi-component copolymer of these and an unsaturated dicarboxylic acid ester and / or vinyl ester and The dicarboxylic acid anhydride unit can be changed to a dicarboxylic acid unit or a half ester unit by modifying with / or an alcohol. In the present invention, those obtained by replacing some or all of the unsaturated dicarboxylic acid anhydride units of the copolymer or multi-component copolymer with dicarboxylic acid units or half ester units can also be preferably used. .

To carry out hydrolysis, the ethylene-based copolymer (A) is used.
80 to 80% in the presence of a catalyst (eg, a tertiary amine) in an organic solvent (eg, toluene) that dissolves the copolymer.
0.5-10 hours with water at a temperature of 100 ° C (preferably 2
It can be obtained by reacting for ~ 6 hours, preferably 3-6 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 0.5 parts by weight) of tertiary amine and dicarboxylic acid in the copolymer based on 100 parts by weight of the ethylene copolymer (A). Generally 0.1 to 3.0 times mol per unit (desirably,
1.0 to 2.0 times mol) of saturated alcohol above the melting point of the ethylene-based copolymer (A), but below the boiling point of the alcohol used, usually used in the field of rubber and synthetic resins, Banbury mixer, extruder It is a method of reacting while kneading for several minutes to several tens of minutes (desirably 10 minutes to 30 minutes) using a kneader such as.

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 to dicarboxylic acid and the half-esterification rate are both 0.5 to 100%, preferably 10 to 100%.

The ethylene unit in this ethylene copolymer (A) is 30 to 99.
5% by weight, preferably 30-99.0% by weight, especially 35-9
9.0 wt% 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 polymer in which the proportion of the carboxylic acid unit, its anhydride unit and half ester unit in the ethylene-based copolymer (A) is less than 0.1% by weight is used, the ethylene-based copolymer (described later) ( 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 in which the copolymerization ratio of unsaturated dicarboxylic acid ester and / or vinyl ester exceeds 70% by weight is used, the softening point of the copolymer becomes high, and the fluidity at a temperature of 150 ° C. or lower Not only is it undesirable because it is damaged, but it is also not economically desirable.

(B) ethylene-based copolymer (B) the ethylene-based copolymer used in the present invention
(B) is composed of "at least one unit selected from the group consisting of a hydroxyl unit, an amino unit and a glycidyl unit" (hereinafter referred to as "the second component (B)") and an ethylene unit, and the ethylene unit is 30 to 99.5%. It is an ethylene-based copolymer containing wt%.

This ethylene-based copolymer (B) is a copolymer that can be obtained by copolymerizing the following monomer, which is the second component (B), with ethylene, and a multi-component copolymer of these and other monomers, Saponification products obtained by saponifying a copolymer of ethylene and a vinyl ester (in particular, vinyl acetate) can be mentioned.

As the second component (B), glycidyl alkyl (meth) acrylate represented by the following general formula, hydroxyalkyl (meth) acrylate (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).

(Here, 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 are butenetricarboxylic acid monoglycidyl ester, glycidyl methacrylate, and glycidyl. Acrylate, glycidyl ethacrylate, itaconic acid glycidyl ester, hydroxymethyl (meth) acrylate, hydroxyethyl (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 99.
5% by weight, preferably 30-99.0% by weight, especially 3
5-99.0% by weight is suitable. 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. Furthermore, when a multi-component copolymer containing the unsaturated carboxylic acid ester and / or vinyl ester is used, 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.

The ethylene-based copolymer (A) and the ethylene-based copolymer
The melt index of (B) (measured according to JIS K-7210 under condition 4, hereinafter referred to as "MI") is generally 0.001 to 1
000 g / 10 minutes, preferably 0.05 to 500 g / 10 minutes, particularly preferably 0.1 to 500 g / 10 minutes. If 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 they are produced by a copolymerization method, they are usually produced under a high pressure of 500 to 2500 kg / cm ^2.
Copolymerizing ethylene with the second component (A) or the second component (B) or other components in the presence of a side chain transfer agent (for example, an organic peroxide) at a temperature of 120 to 260 ° C. It can be obtained by the method described above and the manufacturing method thereof is well known. Further, a method of producing the ethylene-based copolymer (A) by hydrolysis and / or modification with an alcohol, and the ethylene-based copolymer (B)
Among them, the method of producing by the saponification method is also well known.

(C) Carbon Black Further, the carbon black used in the present invention generally has a specific surface area of low temperature nitrogen adsorption method and BE.
1.5 measured by mercury porosimetry in the range of ²⁰ to 1800 m ² / g and pore volume of 30 to 7500Å as measured by T method.
It is effective to have a specific surface area of 600 to 1200 m ² / g.

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, the specific surface area
50 to 1200 m ² / g), thermal black obtained by thermal method, furnace method and furnace black are preferable.

(D) Production of mixture (1) Mixing ratio In producing the mixture of the present invention, the total amount (total) of the ethylene copolymer (A) and the ethylene 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 ethylene-based copolymer (B)
The mixing ratio is 99 to 1% by weight], preferably 5 to 95% by weight, and particularly preferably 10 to 90% by weight. Even if the mixing ratio of the ethylene copolymer (A) in the total amount of the ethylene copolymer (A) and the ethylene copolymer (B) is less than 1% by weight or more than 99% by weight, the mixture is a mixture. 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 the carbon black to the total amount (total) 100 parts by weight of the ethylene copolymer (A) and the ethylene copolymer (B) is 1.0 to 100 parts by weight, and 5.0 to 1
00 parts by weight is preferable, and 10 to 80 parts by weight is particularly preferable.

When the blending ratio of carbon black is less than 1.0 part by weight, a capacitor sealing material excellent in mechanical strength and compression set cannot be obtained. On the other hand, when it exceeds 100 parts by weight, not only the mechanical strength is remarkably lowered, but also the crosslinking efficiency is deteriorated.

(2) Mixing method In order to produce this mixture, the ethylene copolymer (A), the ethylene copolymer (B) and the carbon black 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, ethylene copolymer (A)
It is necessary that the ethylene-based copolymer (B) and the ethylene copolymer (B) do not substantially undergo a crosslinking reaction (when they are crosslinked, not only the moldability is deteriorated when the resulting mixture is molded and processed as described below, but also the purpose is Is not preferable because it may cause deterioration of heat resistance when the shape of the molded article or the molded article is crosslinked). From this, the temperature of melt kneading depends on the type and viscosity of the ethylene copolymer used,
Room temperature (20 ° C) to 150 ° C is desirable, and 140 ° C or less is preferable.

As a measure of this "substantially not crosslinked", "for ethylene-based copolymer (A) and ethylene-based copolymer (B),
After extraction treatment in boiling toluene for 3 hours, it is preferable that the "residue having a diameter of 0.1 micron or more" (hereinafter referred to as "extraction residue") is generally 15% by weight or less, and preferably 10% by weight or less. 5% by weight or less is optimal.

(E) Sealing of electrolytic capacitor To seal an electrolytic capacitor using the mixture obtained as described above, injection molding method, stamping, which is 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, ethylene copolymer
It is important to mold at a temperature at which (A) and the ethylene-based 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
15% or less is desirable, 10% by weight or less is preferable, and 5% by weight or less is most suitable. For sealing by injection molding method, low pressure transfer molding method, etc., from the above
Obtained by pressing the molten mixture into the mold in the temperature range of 80-160 ° C. The feature of the present invention is that the temperature at which the mixture crosslinks the molded product integrally molded in this way (usually
120-280 ℃) for a certain period of time. It is desirable to slightly pressurize such as 0.1 to 20 kg / cm ² (gauge pressure) while holding. The higher the temperature, the shorter the holding time,
It is usually 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, the sheet material molded at 80 to 160 ° C. which is not substantially crosslinked is preliminarily 160 ° C. to 280 ° C.
It is possible to manufacture an electrolytic capacitor which is sealed in a desired mold at the same time while pressurizing the mold with a pressure of 1 to 40 kg / cm ² (gauge pressure) set in the temperature range of ° C.

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. Further, in order to obtain uniform adhesiveness, a method of applying pressure under a slight load, particularly under reduced pressure, may be performed.

A typical (cylindrical) 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 the sealing material (sealing port, crosslinked product of the mixture) of the present invention. 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, the mechanical strength was measured using a JIS B type dumbbell in accordance with JIS K6301 for the tearability test.

The 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.

An ethylene-acrylic acid copolymer having a MI of 300 g / 10 min as a mixture of ethylene-based copolymer (A), ethylene-based copolymer (B) and carbon black (C) (density 0.954 g / c
m ³ , saponification rate of acrylic acid 20% by weight, hereinafter referred to as “EAA”) and saponification product (saponification degree) obtained by saponifying ethylene-vinyl acetate copolymer having a vinyl acetate copolymerization rate of 28% by weight. 97.5%, MI75g / 10 minutes, density
0.951 g / cm ³ , hereinafter referred to as “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 a methacrylic acid copolymer (density 0.950 g / cm ³ , methacrylic acid copolymerization ratio 25% by weight) and the above saponified product [mixing ratio 50:50 (weight ratio), hereinafter referred to as "mixture (II)", An ethylene-ethyl acrylate-maleic anhydride terpolymer with MI of 212 g / 10 min (ethyl acrylate copolymerization ratio of 30.7 wt%, maleic anhydride copolymerization ratio of 1.7 wt%) and MI of 123 g / 10 min Some 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 "mixture ( III) "] and a terpolymer of ethylene-methyl methacrylate-maleic anhydride having an MI of 105 g / 10 min (copolymerization ratio of methyl methacrylate 20.5
% By weight, maleic anhydride copolymerization ratio 3.1% by weight) and ethylene-methyl methacrylate-glycidyl methacrylate terpolymer (methyl methacrylate copolymerization ratio 18.6% by weight, glycidyl methacrylate copolymerization ratio)
12.7% by weight) (mixing ratio 30:70 (weight ratio),
Hereinafter, "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 produced by the furnace method as carbon black in 100 parts by weight of EAA and saponified product (Showa Cabot Co., trade name Show Black FEF,
An average particle size of 51 millimicrons (nm), a specific surface area of 41 m ² / g, hereinafter referred to as “BC”] 60 parts by weight was added. Then, a sheet was formed while sufficiently kneading each of the above mixtures for 20 minutes using an open roll set to a temperature of 50 ° C. in advance. After forming the sheet, square pellets were prepared using a sheet cutter.

The mixtures (I) to (IV) obtained as described above, EAA, a mixture (composition) consisting of saponified product and carbon black, and only the mixture (I) (Comparative Example 3) were extruded using a T-die. Using a machine (diameter 40 mm, die width 30 cm, rotation speed 85 rotations / minute), a film having a thickness of 100 μm was formed under the conditions where the cylinder temperature is shown in Table 1. The extraction residue of the obtained film was measured. In all cases, it was 0%.

Examples 1 to 4 and Comparative Examples 1 to 3 Each of the sheets thus obtained was subjected to a pressure of 20 kg / cm ² (gauge pressure) using a heat press machine at a 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.

In addition, the compression set test was conducted at a temperature shown in Table 2 for 15 minutes using a heat press machine at 200 kg / cm ² (gauge pressure).
A sample according to JIS K6310 was manufactured under pressure. Also,
The tearability test was performed 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 5, Comparative Example 4 Each of the sheets used in Example 1 and Comparative Example 2 was cut into a columnar encapsulation having a diameter of 5 mm and a height of 3 mm, and the diameter was 5 mm, the inner diameter was 1 mm, and the height was 1 mm. A 15 mm cylindrical aluminum container was heated to 300 ° C. and inserted 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 2. In the column of “Solder heat resistance” in this table, “◯” means that no deformation was observed, and “X” means that the prototype was not retained by melting.

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

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) Since the adhesiveness to the capacitor case is excellent, the evaporation of the electrolytic solution and the infiltration of impurities such as moisture are small, and therefore the electrical characteristics of the electrolytic capacitor do not deteriorate, and it should be used in a stable state for a long time. You can

(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 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. A carboxylic acid unit, a dicarboxylic acid unit,
An ethylene copolymer comprising at least one unit selected from the group consisting of an anhydride unit and a half ester unit and an ethylene unit, and having an ethylene unit content of 30 to 99.5% by weight, (B) a hydroxyl unit. , An ethylene copolymer comprising at least one unit selected from the group consisting of an amino unit and a glycidyl unit and an ethylene unit, and having an ethylene unit content of 30 to 99.5% by weight, and (C) a carbon black. It is a mixture, the mixing ratio of any ethylene-based copolymer in the total amount of these ethylene-based copolymer is 1 to 99 wt%, the total amount of these ethylene-based copolymer 100 parts by weight The mixing ratio of carbon black to 1.0 to 100 parts by weight is an electrolytic capacitor using a crosslinked product obtained by crosslinking a mixture as a sealing material.