JPH03181112A - Capacitor - Google Patents

Abstract

PURPOSE:To obtain a capacitor excellent in heat insulation by using an expansive film consisting of a specified polyether copolymer as a dielectric. CONSTITUTION:A polyether copolymer is constituted of the repeat unit expressed by the formulas I and II. Hereupon, the mol composition ratio [(I)/{(I)+(II)}] of the repeat unit expressed by the formula I is made 0.15-0.40, and also the melt viscosity at a temperature of 400 deg.C is made 500 poise or more. If the mol composition ratio is less than 0.15, the glass transition temperature of the polyesther copolymer becomes low, and heat insulation lowers or melting point becomes high, and the moulding property deteriorates. While, if it exceeds 0.40, the crystal property is lost, and the heat insulation and solvent resistance lowers. Moreover, if the viscosity is less than 500 poise, enough heat resistance and mechanical strength can not be attained. To make this polyether copolymer, for example, dihalogenobenzonitrile and 4,4'-biphenyl, and 4,4'- dihalogenobenzophenone are made to react, under the existence of an alkali metal oxide, within neutral polarity solvent.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a capacitor using a plastic film as a dielectric, and more particularly to a capacitor using a stretched film made of a specific polyether copolymer.

[Prior art and problems to be solved by the invention] In recent years,
Capacitors that use plastic films as dielectrics have become popular in the electronic and electrical fields.

This capacitor generally has a structure in which plastic films and metal foils are alternately sandwiched and facing each other, or a structure in which plastic films on which metal films are formed are laminated into flat plates or concentrically wound.

Such so-called plastic film capacitors have features such as excellent electrical characteristics, easy miniaturization, and high reliability.

Incidentally, recent capacitors are required to be heat resistant in order to cope with the harsh operating conditions of electronic and electrical equipment.

However, since conventional plastic film capacitors use films such as polyester and polycarbonate as dielectric materials, they have the problem of not being able to withstand high-temperature usage conditions (for example, the usage temperature of polycarbonate film is 125°C). below).

The present invention has been made to improve the above situation.

That is, an object of the present invention is to provide a capacitor using a plastic film as a dielectric material which has excellent heat resistance.

[Means for Solving the Problem] The configuration of the present invention for achieving the above object is expressed by the following formula (1).
: It has a repeating unit represented by () and a repeating unit represented by the following formula (II) (II), and the molar composition ratio of the repeating unit represented by the formula (I) [(I)/((I)+
(II))] is 0.15 to 0.4, and a stretched film made of a polyether copolymer having a melt viscosity of 500 voids or more at a temperature of 400°C is used as the dielectric material. It is a capacitor.

The present invention will be explained in detail below.

-Polyether copolymer- One of the important points about the polyether copolymer used in the present invention is that it has a repeating unit represented by the above formula (r) and a repeating unit represented by the above formula (II), and , the molar composition ratio of the repeating unit represented by the formula (I) [(I)/((1)+(II))] is 0.15 to 0.
．． It is within the range of 4.

If this molar composition ratio is less than 0.15, the glass transition temperature of the polyether copolymer will be low, resulting in a decrease in heat resistance, or the melting point will be high, leading to deterioration in moldability. On the other hand, if it exceeds 0.4, the crystallinity of the polyether copolymer will be lost and its heat resistance and solvent resistance will decrease.

Furthermore, it is important that the polyether copolymer used in the present invention has a melt viscosity of 500 voids or more at a temperature of 400°C.

This is because a low molecular weight polyether copolymer having a melt viscosity of less than 500 voids cannot achieve sufficient heat resistance and mechanical strength.

The polyether copolymer used in the present invention has, for example, a crystal melting point of about 330 to 400°C, has crystallinity, has a sufficiently high molecular weight, and has sufficient heat resistance, solvent resistance, and mechanical properties. Excellent strength.

-Production method of polyether copolymer- The polyether copolymer is prepared by, for example, dihalogenobenzonitrile, 4,4゛-biphenol, and 4゛4゛-dihalogenobenzophenone in an alkali solution in a neutral polar solvent. Efficient production can be achieved by reacting in the presence of a metal compound.

Specific examples of the dihalogenobenzonitrile include 2,6 dihalogenobenzonitrile represented by the following formula: (wherein, X is a halogen atom), and the following formula; .

X has the same meaning as above.

) 2,4-dihalogenobenzonitrile and the like can be mentioned.

Among these, 2,6-dichlorobenzonitrile, 2,6-difluorobenzonitrile, 2.4
-dichlorobenzonitrile, 2,4-difluorobenzonitrile, and 2,6-dichlorobenzonitrile is particularly preferred.

Next, the 4,4°-biphenol is a compound represented by the following formula.

Next, the above-mentioned 4,4°-dihalogenobenzophenone is a compound represented by It can be used particularly preferably.

The alkali metal compound is not particularly limited as long as it can convert the 4,4°-biphenol into an alkali metal salt, but alkali metal carbonates and alkali metal hydrogen carbonates are preferred.

Examples of the alkali metal carbonates include lithium carbonate, sodium carbonate, potassium carbonate, rubidium carbonate,
Examples include cesium carbonate.

Among these, preferred are sodium carbonate and potassium carbonate.

Examples of the alkali gold hydrogen carbonate include lithium hydrogen carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate,
Examples include rubidium hydrogen carbonate and cesium hydrogen carbonate.

Among these, preferred are sodium hydrogen carbonate and potassium hydrogen carbonate.

Among the various alkali metal compounds mentioned above, sodium carbonate and potassium carbonate can be particularly preferably used.

Examples of the neutral polar solvent include N,N-dimethylformamide, N,N-diethylformamide, N,
N-dimethylacetamide, N,N-diethylacetamide, N,N-diethylacetamide, N,N-dimethylbenzoic acid amide, N-methyl-2-pyrrolidone, N
-ethyl-2-pyrrolidone, N-isopropyl-2-pyrrolidone, N-isobutyl-2-pyrrolidone, N-n-
Propyl-2-pyrrolidone, N-n-butyl-2-pyrrolidone, N-cyclohexyl-2-pyrrolidone, N-methyl-3-methyl-2-pyrrolidone, N-ethyl-3-
Methyl-2-pyrrolidone, N-methyl-3,4,S -)
-dimethyl-2-pyrrolidone, N-methyl-2-piperidone, N-ethyl-2-piperidone, N-isopropyl-2-piperitone, N-methyl-6-methyl-2-piperidone, N-methyl-3-ethylpiperitone , dimethyl sulfoxide, diethyl sulfoxide, 1-methyl-1
-Oxosulfolane.

1-ethyl-I-oxosulfolane, 1-phenyl-l
-oxosulfolane, N,N-dimethylimidazolidinone, diphenylsulfone, and the like.

The ratio of the 4,4'-biphenol and the alkali metal compound used is usually 1.0 to 2.5 mol of the alkali metal compound per 1 mol of 4.4'-biphenol, preferably 4,4'-biphenol. 1 mole per day, and 1.03 to 1.5 moles of the alkali metal compound.

In addition, the total amount of the dihalogenobenzonitrile, 4,4'-biphenol, and dihalogenobenzophenone is usually 1.01 to 1% per 200 mJ of the neutral polar solvent.
Mol, preferably 0. [Use as much as 15 to 0.3 mol.

Further, the usage ratio of the dihalogenobenzonitrile is 4
．． The molar ratio to the total amount of 4'-dihalogenobenzophenone is usually 0.15 to 0.40, preferably 0.
20 to 0.30.

Further, the total amount of the 4,4'-dihalogenobenzophenone and the dihalogenobenzonitrile used is the 4,4'-dihalogenobenzophenone,
molar ratio to °-biphenol, usually 0.98 to 1
．． It is low.

The reaction conditions include adding the dihalogenobenzonitrile, the 4,4′-biphenol, the alkali metal compound, and 4,4°-dihalogenobenzophenone simultaneously or sequentially to a neutral polar solvent. , usually 15
A series of reactions are carried out at a temperature ranging from 0 to 380°C, preferably from 180 to 330°C.

If the reaction temperature is less than 150°C, the reaction rate is too slow to be practical, and if it exceeds 380°C, side reactions may occur.

In addition, the reaction time of this series of reactions is usually 0.1 to 10
time, preferably 1 hour to 5 hours.

After completion of the reaction, the polyether copolymer produced can be obtained by separating and purifying the solution in a neutral polar solvent according to a known method.

For example, if the neutral polar solvent is directly distilled off from a neutral polar solvent solution containing a polyether copolymer, a polyether copolymer powder with a high bulk density can be obtained.

The distillation temperature during distillation depends on the type of neutral polar solvent, but is usually 50 to 250°C, preferably 15°C.
The temperature is 0 to 200°C.

In addition, the distillation pressure during distillation is usually 5 to 760
mmH! , preferably 10 to 200 mm Hg.

When the solvent is directly distilled off in this way, a polyether copolymer powder is obtained as a distillation residue, and this powder can be subjected to conventional purification operations.

As described above, the polyether copolymer used in the present invention can be efficiently produced through simple steps.

Forming a polyether copolymer into a film - Next, a stretched film is produced from the polyether copolymer using a known method.

For example, this polyether copolymer is supplied to an extruder, melted and extruded through a slit in a die at a resin temperature of 350 to 450°C, and then cooled and solidified (T-die method, inflation method), or the polyether copolymer is is supplied to a hot press machine, hot pressed at a pressing temperature of 350 to 450°C, and cooled and solidified (hot press method) to obtain an unstretched film. Furthermore, the unstretched film is not limited to the above-mentioned method, and may be produced by a calendar method or the like.

Next, the unstretched film thus obtained is applied to a stretching machine to produce a stretched film.

By stretching the unstretched film and heat-treating it if necessary,
Since the polyether copolymer is crystallized, various physical properties including electrical properties (especially tan δ) and tensile strength are significantly improved compared to an unstretched film.

In the present invention, a uniaxial stretching method can also be employed, but a two-car stretching method is preferred.

Stretching may be performed simultaneously or sequentially.

What is the stretching ratio? , about 5 to 5 times is preferable, and the stretching temperature is usually in the range of 180 to 300°C.

The obtained stretched film is further stretched under tension or syg.
It is preferable to subject the material to a heat treatment.The temperature of this heat treatment is usually 180 to 280 DEG C., and the heat treatment time is about 1 to 300 seconds.

- Manufacture of capacitors Stretched films are used as dielectrics.

A capacitor is manufactured by alternately laminating this stretched film and metal foil as a conductor into plate shapes or by winding them concentrically.

Alternatively, a thin metal film is formed on the surface of the stretched film by vacuum evaporation, ion sputtering, etc., and the stretched film with the metal thin film is laminated in a plate shape or wound in the same circle to manufacture a capacitor. .

As the metal of the metal foil or metal thin film, aluminum, zinc, tin, titanium, nickel, or an alloy thereof is generally used.

The thus obtained capacitor is used by attaching a lead wire or by directly soldering it to the surface of a substrate.

As described above, the capacitor of the present invention uses a stretched film of a specific polyether copolymer as a dielectric material.

Compared to capacitors using films such as polycarbonate or polyester, it has significantly higher heat resistance, and has a constant dielectric constant and dielectric loss tangent over a much wider temperature range.

[Example] Next, the present invention will be described in more detail based on Examples and Comparative Examples.

(Example 1) 1,548 g of 2,6-cyclobenzonitrile was placed in a reactor with an internal volume of 5 lengths equipped with a Dean-Starck trap filled with toluene, a stirring device, and an argon gas blowing tube.
g (9 mol), 4,4°-dophenol 5.580 g
(30 mol), potassium carbonate 4,561 g (:1
3 mol) and 50 moles of N-methylpyrrolidone, and while blowing argon gas, the temperature was raised from room temperature to 19 mol for 1 hour.
The temperature was raised to 5°C.

After raising the temperature, a small amount of toluene was added and the produced water was removed by azeotropy.

Next, after carrying out a reaction at a temperature of 195°C for 30 minutes, 4,4°-difluorobenzophenone 4.582
A solution of g (21 mol) dissolved in 70 M of N-methylpyrrolidone was added, and the reaction was further carried out for 1 hour.

After the reaction, the product was pulverized with a blender (manufactured by Warninck), washed with wood and methanol in that order, and then dried to obtain 10.0 kg of white powdery copolymer (yield: 98%).
I got it.

When the properties of this copolymer were measured, it was found that the temperature of 40
Melt viscosity at 0°C (zero shear viscosity) 13.000
Boyce, glass transition temperature 182°C, crystal melting point 379°C
1 thermal decomposition onset temperature was 562°C (5% weight loss in air).

This copolymer consists of repeating units represented by the formulas (I) and (II) above, and has a molar composition ratio of [(N/(I)+
(ff)] was 0.3.

Next, this polyether copolymer was supplied to a twin screw extruder (PCM-30 manufactured by Ikegai Tekko Co., Ltd.) and extruded at a temperature of 390°C to form pellets.

Using this pellet, extrusion molding is performed using a T-die,
A 5 cm film was obtained.

When we measured the physical properties of this film, we found that the tensile strength was 8K.
g/mm2. Tensile modulus 250Kg/mm2. The elongation at break was 150% (according to ASTM D 882).

Next, this film is stretched using a biaxial stretching machine (manufactured by Toyo Seiki Seisakusho).
The film was stretched three times in both length and width directions at a stretching speed of 1000%/min and a temperature of 188°C, and heat treated at 260°C for 30 seconds below the foot length to obtain a biaxially oriented film with a thickness of 8IL.

The tensile strength of this biaxially oriented film is 30K g/m
m2, tensile modulus 420 Kg/mm2. Breaking elongation 30
%Met.

The biaxially oriented film produced in this way was then set in a vacuum deposition apparatus, and an aluminum film was deposited on the surface of the film so that the film resistance was 5Ω/hole.

The resulting settled film was slit and passed through an element winding machine to produce a capacitor element, and the ends were sealed and lead wires were attached according to conventional methods to produce a capacitor with a capacity of 0.1 F.

The tan δ of this capacitor at 25°C and 140°
The tan δ ratios at 180° C. and 180° C. were measured.

The results are shown in Table 1.

(Comparative Example 1) A capacitor with a capacity of 0.1 #F was prepared in the same manner as in Example 1, except that a biaxially oriented film of polyethylene terephthalate [Unitika Niembret ■] was used as the dielectric. Performance was evaluated.

The results are shown in Table 1.

(Comparative Example 2) Polycarbonate [manufactured by Idemitsu Petrochemical Co., Ltd.] was used as the dielectric material.
A capacitor was produced in the same manner as in Example 1, except that a biaxially oriented film of Idemitsu polycarbonate A 25001 was used.

The performance evaluation is as shown in Table 1.

Table 1 [Effects of the Invention] (1) According to the present invention, since a stretched film made of a specific polyether copolymer is used as a dielectric material,
It is possible to provide a capacitor with excellent heat resistance that can be used up to around °C.

Therefore, the capacitor of the present invention makes a significant contribution to the field of electrical and electronic equipment, which has recently come to require severe conditions regarding operating temperatures.

Claims (1)

[Claims] (1) The following formula (I); ▲There are mathematical formulas, chemical formulas, tables, etc.▼ The repeating unit represented by (I) and the following formula (II): ▲Mathematical formula,
There are chemical formulas, tables, etc. ▼ Having a repeating unit represented by (II), the molar composition ratio of the repeating unit represented by formula (I) [(I)/{(I)
+(II)}] is 0.15 to 0.40, and a stretched film made of a polyether copolymer having a melt viscosity of 500 poise or more at a temperature of 400° C. is used as the dielectric material. capacitor.