JP2830376B2 - Heat resistant capacitors - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a heat-resistant capacitor, and more specifically, to a film made of a resin obtained by blending a resin having low heat resistance and an aromatic polyamide. Related to a heat-resistant capacitor.

[Prior Art] As a material of a film used as a dielectric of a film capacitor, there are generally polyethylene terephthalate, polypropylene and the like. In recent years, the miniaturization of electrical equipment has progressed, and the parts used have been miniaturized, but the same applies to capacitors.Polyphenylene sulfide, which has higher heat resistance, as manufacturing conditions and operating temperature rise, etc. , Polycarbonate and the like have begun to be used for some applications. Further, aromatic polyamides and the like having higher heat resistance have been studied.

[Problems to be Solved by the Invention] However, recent production conditions have become increasingly severe, and polyphenylene sulfide has become unusable, and amorphous polymers such as polycarbonate have a high glass transition point and an electrical resistance. Although it has excellent properties and humidity properties, it has a drawback in that the mechanical properties at high temperatures inherent in amorphous polymers are poor.

On the other hand, aromatic polyamides and the like are known as heat-resistant films and have good heat resistance and mechanical properties, but not only cost is high due to poor productivity, but also fatal humidity properties as film capacitors, There is a disadvantage that electric characteristics are poor.

The present invention solves the above problem and provides a heat-resistant capacitor using a film that is excellent in heat resistance, mechanical properties, chemical properties (mainly humidity properties), surface properties, and economy (cost). With the goal.

Means for Solving the Problems In order to achieve the above object, the present invention comprises a blend resin of an aromatic polyamide and a soluble resin, wherein the amount of the aromatic polyamide is 5% by weight or more and 90% by weight of the blended resin. %
A heat-resistant capacitor characterized by using a film having the following range as a dielectric.

The aromatic polyamide of the present invention is one or more of the general formula Those containing 50 mol% or more of the repeating unit represented by are preferable, and those containing 70 mol% or more are more preferable.

Here, Ar ₁ and Ar ₂ are composed of one or more structures containing at least one aromatic ring, and may have the same composition or different ones. Representative examples thereof include the following.

Also, part of the hydrogen on these aromatic rings are halogen (especially chlorine), a nitro group, an alkyl group of C ₁ -C ₃ (especially methyl), such as alkoxy groups C ₁ -C ₃ Also includes those substituted with a substituent. X represents —O—, —CH _{2
-, - SO 2 -, -} S -, - CO- , and the like. These are included in the form of homopolymer or copolymer.

From the viewpoint of improving the heat resistance which is the object of the present invention, Ar ₁ ,
Ar ₂ preferably has a rigid structure mainly in a para-orientation, and those having a substituent such as a halogen group or an alkyl group on the aromatic ring are more preferable because of high solubility in a solvent and compatibility with a soluble resin. Further, a halogen group is preferable because it improves the humidity characteristics of the obtained film.

Further, solubility in solvents, from the viewpoint of compatibility with the soluble resin is _{high, -O -, - CH 2 -} , - SO 2 -, - S-, -CO- two aromatic rings via a It is also preferable that the bonded structure is copolymerized, but if it is too large, the thermal characteristics, mechanical characteristics, and humidity characteristics are adversely affected.

That is, Is preferable. Ar ₁ , Ar ₂
The groups other than Ar ₃ , Ar ₄ , Ar ₅ , Ar ₆ , and Ar ₇ constituting the above are not particularly limited as long as the above formula is satisfied.

For example, A solution of one or more aromatic polyamides represented by, for example, a soluble resin, the pot life is extremely stable even when stored for a long time, and the resulting film is tough and has good heat resistance and good humidity characteristics. .

In addition, the soluble resin of the present invention means one or more resins that dissolve at 1% by weight or more in a solvent that dissolves the aromatic polyamide described above, and is not particularly limited. As a solvent for dissolving both the aromatic polyamide and the soluble resin, an organic solvent is preferable in consideration of ease of handling and the like, and N-methyl-2-pyrrolidone, dimethylacetamide, hexamethylenephosphoramide, dimethylformamide, dimethylformamide Examples include amide polar solvents such as imidazolidinone and dimethyl sulfone.
Mixtures of -methyl-2-pyrrolidone and N-methyl-2-pyrrolidone with other amide polar solvents are preferred. Particularly when these solvents are used, polycarbonate, polyvinylidene fluoride, polymethyl methacrylate, polystyrene, polyvinyl alcohol, polyether sulfone, polysulfone, polyarylate, polysulfide sulfone, and polyetherimide are preferable, and the mechanical properties at high temperatures are preferable. Amorphous resins which are remarkably improved and have excellent humidity characteristics, such as polycarbonate, polyether sulfone, polysulfone, polyarylate, and polysulfide sulfone, are more preferable. Especially, Since the resin having both the basic skeleton A and the structure of CＯO is very good in compatibility with the aromatic polyamide, a blend solution obtained by dissolving the aromatic polyamide and the soluble resin in the above-mentioned solvent has a long term. It is more preferable because a film having excellent storage stability and excellent mechanical properties and transparency can be obtained. For example, polycarbonate, polyarylate and the like can be mentioned, and polycarbonate is more preferred from the viewpoint of economy. The basic skeleton A may have a substituent, such as a halogen group. Further, in the blend resin of the aromatic polyamide and the soluble resin, a resin different from the resin used as the third component is preferably 40% by weight or less of the soluble resin, more preferably 30% by weight or less, Preferably, 20% by weight or less may be added. As another resin, an aromatic polyamide having a structure different from that of the blended aromatic polyamide or a soluble resin different from the soluble resin used is preferable. For example, when using polycarbonate as a soluble resin,
When polyether sulfone, polysulfone, or the like is added to this, mechanical properties are improved. In addition to the above solvents,
Good solvents for soluble resins, for example, dioxane, tetrahydrofuran, methylene chloride, chloroform, 1,1,2-trichloroethane, tricrene, acetone, toluene and the like,
As long as it does not prevent the soluble resin and the aromatic polyamide from being compatible with each other, the content may preferably be within 20% by weight, more preferably within 15% by weight of the total amount of the solvent.

A film made of the blend resin is obtained by forming the above-mentioned blend solution into a solution.

It is necessary that the amount of the aromatic polyamide in the film of the present invention is in the range of 5% by weight to 90% by weight of the blend resin. When the amount of the aromatic polyamide is less than this range, the effect of improving the heat resistance is no longer observed, and the mechanical properties at high temperatures are extremely deteriorated. It is preferably at least 7% by weight, more preferably at least 10% by weight. On the other hand, if the amount of the aromatic polyamide is larger than this range, the economic merit is lost, and the humidity characteristics are deteriorated. Preferably 70
% By weight, more preferably 50% by weight or less.

The center line depth Rp of the surface of the film of the present invention is 10 to 50.
Preferably it is 00 nm. If the thickness is less than 10 nm, the handleability of the film deteriorates, the surface is damaged by the rubbing between the films, and insulation defects increase. As a result, for example, the withstand voltage failure rate when a capacitor is used increases. If it is larger than 5000 nm, the stability of the dielectric properties of the same film becomes poor, and for example, the variation in capacitance when used in a capacitor becomes large. More preferably, it is 10 to 2000 nm.

Furthermore, the average cross-sectional flatness P of the surface projections of the film of the present invention is preferably 0.005 to 0.3. If it is less than 0.005, the projections are too flat, the handleability of the film deteriorates, the surface is damaged by the rubbing of the films, and the insulation defects increase. As a result, for example, the withstand voltage failure rate when a capacitor is used increases. If it is larger than 0.3, the projection is too sharp,
Due to the shaving of the projections, the stability of the dielectric properties of the same film deteriorates, and for example, the variation in capacitance when used in a capacitor increases. More preferably, 0.05 to
0.15.

Further, Ra (center line average roughness) of the surface of the film of the present invention
Is preferably 10 to 500 nm, more preferably 30 to 300 nm.

Furthermore, Rz (10-point average roughness) of the surface of the film of the present invention
Is preferably 50 to 5000 nm, more preferably 100 to 3000 nm
It is. In this case, the above effect is more apparent, which is particularly preferable.

In order to achieve the above surface roughness, inorganic and organic fine particles are added, and the added amount is preferably 0.05 to 10% by weight.
0.1 to 5% by weight is more preferable) and particle size (average particle size is 0.0
It is effective to adjust the stretching temperature and the stretching ratio, preferably from 05 to 1.0 μm, more preferably from 0.01 to 0.8 μm.

Under a load of at least one direction (0.5 k
The thermal dimensional change at 250 ° C. in g / mm ² ) is preferably 50% or less.
If it is more than 50%, it cannot withstand use at high temperatures under tension. It is more preferably at most 40%, further preferably at most 20%.

The heat shrinkage at 250 ° C. in at least one direction of the film obtained in the present invention is preferably 20% or less. It is more preferably at most 10%, further preferably at most 5%. 20%
If it is larger, the dimensional stability is poor, and it is not practical. The heat shrinkage at 200 ° C. in at least one direction is 10
% Or less, and more preferably 5% or less. further,
The heat shrinkage at 300 ° C. in at least one direction is preferably 30% or less, more preferably 20% or less. The coefficient of thermal expansion in at least one direction is preferably 5 × 10 ⁻⁵ / ° C. or less, and 4 × 1
It is more preferably 0 ⁻⁵ / ° C. or less. If it exceeds 5 × 10 ^-5 / ° C,
There is a concern that dimensional fluctuations may occur during immersion in the solder bath, and it cannot be used.

The moisture absorption of the film is preferably 5% or less, more preferably 3% or less, and still more preferably 1% or less. 5%
If it is larger, the dimensional change due to moisture absorption becomes large, and it is not practical. The coefficient of humidity expansion in at least one direction is 5
× 10 ⁻⁵ /% RH or less is preferable. It is more preferably 4 × 10 ⁻⁵ /% RH or less.

The film of the present invention has an elongation at break in at least one direction of 10
% Or more is preferable. It is more preferably at least 15%, further preferably at least 20%. If it is less than 10%, the film will be broken during handling and processing of the film, which is not practical. The strength in at least one direction is preferably 5 kg / mm ² or more, more preferably 7 kg / mm ² or more, and further preferably 9 kg / mm ² or more. The Young's modulus in at least one direction is preferably 150 kg / mm ² or more, more preferably 200 kg / m
m ² or more.

The thickness of the film of the present invention is preferably 0.2 to 200 μm,
1 to 50 μm is more preferred. The density of this film is
1.0 to 1.5 g / cm ³ is preferable, and 1.1 to 1.4 g / cm ³ is more preferable.

The dielectric constant (1 kHz) of the film of the present invention is preferably from 2 to 7. The dielectric loss tangent (1 kHz) is preferably 3% or less. More preferably, it is 2% or less.

Further, the tear resistance in at least one direction of the film of the present invention is preferably 0.05 kg / μm or more. If it is at the end, the film will be broken during handling and processing of the film, which is not practical. More preferably, it is 0.1 kg / μm or more, further preferably 0.3 kg / μm or more.

Next, the film production method of the present invention will be described, but is not limited thereto.

The aromatic polyamide of the present invention is obtained by reacting a diisocyanate with a dicarboxylic acid or a diacid chloride with a diamine. In the case of diacid chloride and diamine, N
It is synthesized by solution polymerization in an amide-based polar solvent such as -methyl-2-pyrrolidone or dimethylacetamide, or by interfacial polymerization using an aqueous medium. Diacid chloride and diamine are mixed at low temperature (usually 50
C., preferably 30.degree. C. or lower) for 1 to 2 hours with stirring. The order of adding the monomers is not particularly limited. Hydrochloric acid generated after the polymerization is neutralized with an inorganic alkali or an organic neutralizing agent. The reaction between the diisocyanate and the dicarboxylic acid is carried out in an amide-based polar solvent in the presence of a catalyst, usually at a high temperature (50 to 200 ° C.). These polymer solutions may be directly used as stock solutions for blending,
Alternatively, the polymer may be isolated once and then redissolved in a solvent to prepare a stock solution for blending. In some cases, an inorganic salt such as calcium chloride or magnesium chloride is added to the stock solution for blending as a solubilizing agent.

In order to improve the mechanical properties of the heat-resistant film, it is necessary to keep the molecular weight of the polymer at a certain level or more, and it is convenient to _{express the} intrinsic viscosity (η _inh ) as a measure for this. That is, the intrinsic viscosity is preferably 1.0 to 10.0.
0, more preferably 1.5 to 7.0.

As a method of blending the aromatic polyamide and the soluble resin, a method of separately preparing a stock solution of each of the aromatic polyamide and the soluble resin and blending the stock solutions with each other, an amide polar solvent solution in which the soluble resin is dissolved is used. In this method, the aromatic polyamide is polymerized, and the polymerization and the blending are performed simultaneously. In particular, when separately preparing the respective stock solutions of the aromatic polyamide and the soluble resin and blending the stock solutions, the temperature of the solution is 25 to 100 ° C., preferably 30 to 8 ° C.
It is preferable to stir at 0 ° C. for 30 minutes or more. If the temperature is lower than this and the stirring time is not sufficient, the surface may become rough when formed into a film. Then, as described above, inorganic and organic fine particles are added in order to control the surface roughness of the film. The apparent intrinsic viscosity obtained from the membrane-forming stock solution thus obtained is preferably from 0.1 to 8.0, more preferably from 0.2 to 5.0. The solution viscosity can be freely selected, but from the viewpoint of castability is preferably 5 to 50,000 poise / 30 ° C., and 10
~ 20,000 poise is more desirable. The resin concentration is preferably 1 to 50%, more preferably 5 to 30%.

This film forming stock solution is formed into a film by the following method. First,
Although it is a dry-wet method, it is cast on a support in the form of a film by a doctor knife, a mouthpiece, or the like, and is usually dried at a temperature in the range of 50 to 250 ° C, more preferably 60 to 200 ° C for a certain time. If the temperature is lower than 50 ° C., the evaporation rate of the solvent is slow. The dried film is peeled from the support, and immersed in or sprayed with an aqueous medium to extract the inorganic salt and the solvent. The aqueous medium is a liquid containing water as a main component and is a poor solvent for a polymer, but is a liquid having an affinity for an inorganic salt or an amide-based polar solvent. For example, water alone, a mixture of water and an amide-based polar solvent constituting a stock solution, a mixture of water and ethylene glycol, acetone, and a lower alcohol may be mentioned. At least 50% or more of the water is desalinated. It is desirable in consideration of the rate of solvent removal and solvent recovery. The temperature of the wet bath is usually 5 to 90 ° C. In the wet process, an inorganic salt serving as a solubilizing agent and an amide-based polar solvent are extracted. In the film immediately after the completion of the wet process, the residual amount of the inorganic salt is 3% or less per polymer, more preferably 1%. The following is good. The residual ratio of the amide polar solvent is not particularly limited, but it is advantageous to extract as much as possible in consideration of solvent recovery. The film in the wet process is easily stretched in a wet temperature range because it is swollen with an aqueous medium, and in order to improve the mechanical properties of the final film, it is generally stretched in the longitudinal direction by 1.01 to 5.0 times in the process. You. The film after the wet process is heated for evaporation of the aqueous medium and evaporation of the amide polar solvent. In this heating step, the final treatment is 100 ° C or higher, preferably 200 ° C or higher and 500 ° C or lower, but once the water is dried at 50 to 100 ° C (the water content is 20% by weight or less based on the weight of the film). Up to this point), heating at the above-mentioned temperature is preferred because a film having the heat and mechanical properties of the present invention can be easily obtained. Also,
In the heating step, the film is stretched 1.0 to 5.0 times in the transverse direction.
If the film is stretched once at 1.0 to 1.2 times at 00 to 200 ° C and then stretched at 200 to 500 ° C in two steps, a film having the surface characteristics of the present invention can be easily obtained. . Also, there is no problem if relaxing is performed as needed.

Next, the wet method is a method in which a film is formed directly on a base or once on a support, and then introduced into an aqueous medium (which may contain alcohol such as methanol or ethanol or may contain only alcohol). is there. Because it contains a large amount of amide-based polar solvents, etc., the rapid replacement of inorganic salts and amide-based polar solvents in aqueous media is likely to cause the generation of voids or roughening of the film in the final film. Inorganic salts such as calcium chloride, lithium chloride, lithium bromide, etc. are included in the aqueous medium to control the substitution rate as necessary, or water is provided in multiple stages, and water and amide-based polar solvents / inorganic salts are used. Or a mixture having a concentration gradient. Like the dry-wet method, the film may be stretched 1.01 to 5 times in the machine direction in this step. The film after the wet process is heated (200 to 500 ° C.) and stretched in two stages in the horizontal direction (1.01 to 5.0 times) in the same manner as in the dry and wet process. Prior to this heating, it is preferable to dry the water once at 50 to 100 ° C., and the drying is performed by a hot roll or hot air.
A longitudinal stretching of up to 5 times is also performed.

Next, a dry method is used. This method is a process in which the extraction step is omitted, contrary to the wet method, and is a method that can be performed only by using an organic solvent and not containing an inorganic salt as a dissolution aid in a stock solution for film formation. The undiluted solution cast onto the support from a doctor knife or mouthpiece is dried and peeled off from the support in the same manner as in the wet-wet method, and the solution is moved 1.01 vertically between the support and the heating step.
Stretched up to 5.0 times. After the dry process, the film is heated and stretched in the same manner as in the dry-wet process. As described above, the film of the present invention can be obtained.

 Next, a method for manufacturing a capacitor will be described.

On the film obtained as above, vacuum evaporation,
A metal thin film is formed by a method such as plating, sputtering, or ion plating to obtain a metallized film serving as a capacitor element. As the metal at this time, aluminum, zinc, nickel, nickel chromium alloy and the like can be mentioned, and among these, aluminum is preferable in terms of vapor deposition properties and characteristics.

Next, the metallized film is wound or laminated to obtain the capacitor of the present invention. For example, if the film is metalized on one side, two sheets are stacked and wound or laminated.If the film is metalized on both sides, the film is wound or laminated with a non-metalized film to form a capacitor element. The exterior is used to make a capacitor. The change in capacitance before and after the capacitor is immersed in a 260 ° C. solder bath for 30 seconds is preferably 10% or less, more preferably 7% or less. The change in withstand voltage before and after storage in an atmosphere at 150 ° C. for 1000 hours is preferably 10% or less, more preferably 7% or less. Both are not practical for use outside of this range.

[Evaluation Method of Characteristics] The measurement methods of the characteristics in the examples are as follows.

(1) Intrinsic viscosity (η _inh ) The intrinsic viscosity was measured by using an Ubbelohde viscometer under the conditions of 0.5 g / 100 ml and 30 ° C. using N-methyl-2-pyrrolidone as a solvent according to the following equation.

(2) Solution Viscosity (Poise) Measured at a temperature of 30 ° C. using a rotary B-type viscometer (Tokyo Keiki).

(3) Elongation at break, strength, Young's modulus, F-5 value 10mm width, 50mm length, tensile speed 3 using TRS type tensile tester
It was measured under the condition of 00 mm / min.

(4) Heat shrinkage (%) After heating for 10 minutes in an oven set at a predetermined temperature with no load, the temperature was returned to room temperature, the dimensions were measured, and calculated by the following formula.

(5) Moisture absorption (%) The film weight was measured after insulation at 150 ° C. for 60 minutes and after standing in 75% RH for 48 hours, and was calculated by the following formula.

Moisture absorption = (75% RH, film weight after standing for 48 hours-film weight when absolutely dry) / (film weight when absolutely dry) × 100 (%) (6) Coefficient of thermal expansion (α) Once the film is 150 to remove the effects of moisture absorption and desorption
It calculated from the dimensional change in the 80-150 degreeC area | region at the time of heating to ℃ and gradually cooling. The dimensional change was measured by a thermomechanical analyzer (TMA).

(7) Humidity expansion coefficient (β) Dehumidification (approx. 30% RH) and humidification (approx.
% RH), the film length at the time of equilibrium was read, and the difference (elongation) was obtained from the following equation.

ΔH: Humidity difference between humidification and dehumidification (% RH) (8) Thermal dimensional change rate under load Apply 0.5 kg / mm ² load, place in oven at 250 ° C for 10 minutes, return to room temperature The dimensions were measured and calculated by the following formula.

(9) Dielectric constant, tan δ According to ASTM-D-150-81.

(10) Center line average roughness Ra, center line depth Rp, and 10-point average roughness Rz were measured using a high-precision thin film step measuring device ET-10 manufactured by Kosaka Laboratory. The conditions are as follows, and the value was determined by averaging 20 times.

・ Stylus of the stylus tip: 0.5 μm ・ Load of the stylus: 5 mg ・ Measuring length: 1 mm ・ Cutoff value: 0.08 mm The definition of the center line average roughness Ra, center line depth Rp, and 10 point average roughness Rz is as follows. For example, Jiro Nara, "Measurement of surface roughness
The center line depth Rp is the distance between the highest peak and the center line of the sampled portion, which is extracted from the roughness curve by the reference length. Means

(11) Film height in a scanning electron microscope [ESM-3200, manufactured by Elionix Inc.] and a cross-section measuring device [PMS-1, manufactured by Elionix Inc.] using an average sectional flatness P2 detection method of surface projections The measured values are sent to an image processing device [IBAS2000, manufactured by Carl Zeiss Co., Ltd.]
Reconstruct the film surface projection image on the image processing device. Next, a circle-equivalent diameter is obtained from the area of each projection obtained by binarizing the projection portion with the film surface projection image, and this is defined as the average diameter of the projection. The highest value among the binarized individual projections is defined as the height of the projection, and this is determined for each individual projection. Relocate this measurement to 500
The average value of the ratio of the height to the average diameter (height / average diameter) of the measured protrusions was defined as the average flatness P. The magnification of the scanning electron microscope is selected to be a value between 1000 and 8000 times.

(12) End crack resistance (kg / μm) Measured in accordance with JIS-C-2318 and converted to a thickness of 1 μm.

(13) Evaluation of capacitor withstanding voltage defect rate 1000 capacitors were manufactured under the same conditions, the withstanding voltage of each capacitor was measured, and the percentage of capacitors that did not reach the specified voltage was calculated. I do. The voltage was applied while increasing at a rate of 100 V / sec, and the voltage at the time when the capacitor was destroyed and a current of 10 mA or more flowed was defined as withstand voltage. The specified voltage was 20 V per 1 μm of film thickness.

(14) Evaluation of variation in capacitor capacitance 1000 capacitors were manufactured under the same conditions, the capacitance of each capacitor was measured using an automatic capacitance bridge, and the variation (standard deviation) was expressed as a percentage to indicate the variation in capacitance. . The smaller the value, the better the stability.

(15) Capacitor characteristics Those with a withstand voltage failure rate and a capacity variation of 10% or less were rated as good (○).

(16) Solder resistance The sample was immersed in a solder bath at 260 ° C for 30 seconds, and the change in capacitance before and after was measured.

(17) Long-term heat resistance After storage in an atmosphere at 150 ° C for 1000 hours, the change in withstand voltage before and after was measured.

[Examples] Next, embodiments of the present invention will be described based on examples, but the present invention is not limited thereto. The parts used in the following examples all represent parts by weight, and the characteristic values different in the vertical and horizontal directions are average values.

Example 1 (1) Production of film 70 mol% of 2-chloroparaphenylenediamine (hereinafter C)
PA) and 30 mol% of 4,4'-diaminodiphenyl ether (hereinafter abbreviated as 4,4'-DAE), and 100 mol% of 2-chloroterephthalic acid chloride (hereinafter abbreviated as CTPC) and N-methyl-2- The reaction was performed at 20 ° C. or lower in pyrrolidone (hereinafter abbreviated as NMP) to obtain an NMP solution of an aromatic polyamide. This solution was poured into a large amount of water, reprecipitated and dried to obtain a powdery polymer. 20 parts of this polymer was dissolved in 200 parts of NMP, and NMP containing 30 parts of polycarbonate which had been separately adjusted
200 parts of the solution was added, the mixture was stirred at 40 ° C. for 4 hours, and 0.2% by weight (based on the total polymer amount) of Syloid 150 (Fuji Divison Chemical) was added to obtain a blend solution.
The intrinsic viscosity was 1.1 and the solution viscosity was 530 poise.

This stock solution for film formation was cast on an endless belt made of stainless steel, and dried with hot air at 160 ° C. until it had self-supporting property. The gel film having self-supporting properties was continuously peeled off from the belt, and then introduced into a water tank, and simultaneously with extraction of the solvent, stretched 1.1 times in the machine direction and guided to a stenter. Dry the water at 80 ° C under constant length with a stenter,
After stretching in the transverse direction by 1.3 times at 160 ° C., the film was further stretched in the transverse direction by 1.5 times (2 times in total) at 280 ° C. to obtain a film having a thickness of 5 μm. The obtained film is referred to as film 1,
The elongation at break of this film: 28%, tensile strength: 11 kg / mm ² ,
Young's modulus: 420 kg / mm ² , crack resistance: 0.58 kg / μm, 25
Heat shrinkage at 0 ° C for 10 minutes: 0.5% under a load of 250 ° C (0.5kg /
mm ² ) thermal dimensional change rate: 17%, thermal expansion coefficient (α): 2.3 × 10
^-5 / ° C, moisture absorption: 0.8%, dielectric constant: 3.2, tan δ: 0.41, Rp: 11
The film was tough and excellent in humidity characteristics, heat resistance, and workability, such as 00 nm, Ra: 120 nm, Rz: 1200 nm, and P: 0.13.

(2) Metallization Aluminum was vacuum-deposited on the film 1 so that the surface resistance became 2Ω. At that time, vapor deposition was performed in a stripe shape having a margin portion running in the longitudinal direction (repeating of a vapor deposition portion having a width of 9.0 mm and a margin portion having a width of 1.0 mm). Next, a blade was inserted into the center of the vapor deposition part and the center of each margin part, slit, and wound into a 5.0 mm-wide tape having a margin of 0.5 mm to the left or right.

(3) Manufacture of a wound body Each of the left and right margins of the obtained reel was wound one on top of another. At that time, the two films were wound while being shifted so that the vapor deposition portion protruded from the margin portion by 0.5 mm in the width direction.

(4) Manufacture of the capacitor Remove the core material from this wound body and leave it at 180 ° C, 10kg /
Pressed at a temperature and pressure of cm ² for 5 minutes. Metallicon was sprayed on both ends to form external electrodes, and lead wires were connected to the metallikon to obtain a wound capacitor. Table 1 shows the evaluation results of the solder resistance, the long-term heat resistance, the capacity variation, and the withstand voltage failure of the capacitor, and the capacitor had good capacitor characteristics.

Example 2 Aromatic polyamide isolated after reaction of 70 mol% of CPA, 30 mol% of 4,4'-diaminodiphenyl sulfone (hereinafter abbreviated as DAS), 50 mol% of CTPC, and 50 mol% of terephthalic chloride (hereinafter abbreviated as TPC) Was dissolved in 300 parts of NMP, and 100 parts of an NMP solution containing 15 parts of polycarbonate were blended. From this blend solution, a film 2 was produced in the same manner as in Example 1. The obtained film has a thickness of 4 μm, a tensile elongation of 22%, and a tensile strength of 14 kg / m.
m ² , Young's modulus: 430 kg / mm ² , end crack resistance: 0.44 kg / μm, thermal shrinkage at 250 ° C. for 10 minutes: 0.5%, thermal dimension under load of 250 ° C. (0.5 kg / mm ² ) Rate of change: 11%, moisture absorption: 1.2%, dielectric constant: 3.2, tan δ: 0.38, Rp: 900nm, Ra: 105nm, Rz: 1000n
m, P: 0.11, and the film was tough and excellent in humidity characteristics, heat resistance, and workability. Further, when a capacitor was produced using this film 2 in the same manner as in Example 1,
It had excellent characteristics as shown in Table 1.

Example 3 In the same manner as in Example 1, CPA 85 mol%, 4,4′-DA
350 parts of an NMP solution containing 10 parts of an aromatic polyamide obtained from the reaction of 15 mol% of E and 100 mol% of CTPC and 40 parts of polyether sulfone were prepared. The solution viscosity was 80 poise at 30 ° C. This undiluted blend solution is continuously extruded into water from a base having a width of 100 mm and a slit of 0.1 mm, and is vertically stretched in water by 1.05 mm.
After stretching the film twice and drying at 95 ° C,
Heating was carried out while stretching 1.2 times and further 1.3 times in the transverse direction at 310 ° C., to obtain a long film 3. The obtained film has a thickness of 4 μm, a tensile elongation of 20%, and a tensile strength of 12 kg / m.
m ² , Young's modulus: 450 kg / mm ² , crack resistance: 0.60 kg / μm, thermal shrinkage at 250 ° C. for 10 minutes: 0.3%, thermal dimension under load of 250 ° C. (0.5 kg / mm ² ) Change rate: 7.1%, moisture absorption rate: 0.7%,
Dielectric constant: 3.0, tan δ: 0.33, Rp: 980 nm, Ra: 95 nm, Rz: 1100
It was a tough film with nm, P: 0.08 and excellent in humidity characteristics, heat resistance and workability. Further, when a capacitor was manufactured using the film 3 in the same manner as in Example 1,
It had excellent characteristics as shown in Table 1.

Example 4 In the same manner as in Example 1, CPA 100 mol% and CTPC 100 mol
% Of aromatic polyamide (η _inh : 6.4) 1
Five parts and 500 parts of an NMP solution containing 35 parts of polycarbonate were prepared. The solution viscosity was 1000 poise at 30 ° C. This blend stock solution was continuously extruded into water from a die having a width of 620 mm and a slit of 0.5 mm, stretched 1.1 times in water in the longitudinal direction, and
After drying the water at 5 ° C., the film was heated at 150 ° C. while stretching 1.2 times in the horizontal direction and further at 300 ° C. while stretching 1.3 times in the horizontal direction to obtain a long film 4. The resulting film has a thickness of 2μ
m, tensile elongation: 23%, tensile strength: 21 kg / mm ² , Young's modulus: 650 kg / mm ² , end crack resistance: 0.75 kg / μm, 250 ° C, 1
Heat shrinkage for 0 minute: 0.5%, under a load of 250 ° C (0.5 kg / mm ² )
Thermal dimensional change: 1.6%, moisture absorption: 0.4%, dielectric constant: 3.3, ta
nδ: 0.40, Rp: 1200 nm, Ra: 110 nm, Rz: 1150 nm, P: 0.10,
The film was tough and excellent in humidity characteristics, heat resistance and workability. Further, a capacitor was produced using this film 4 in the same manner as in Example 1, and had excellent characteristics as shown in Table 1.

Comparative Example 1 A syloid was added to a chloroform solution of polycarbonate.
Example 1 with the addition of 0.2% by weight (based on the amount of polymer) of 150
When a capacitor was made in the same way as in
Although there was no problem with workability and capacitor characteristics, solder resistance and long-term heat resistance were destroyed during measurement and could not be measured.
The heat resistance was poor.

Comparative Example 2 To a NMP solution of an aromatic polyamide obtained from 75 mol% of CPA, 25 mol% of DAE and 100 mol% of CTPC, 0.18 wt% of Aerosil R972 (Nippon Aerosil) was added, and a film was formed in the same manner as in Example 1. Although there was no problem in mechanical properties and workability, as shown in Table 1, the properties were poor when evaluated as a capacitor.

As described above, capacitors made from films outside the scope of the present invention had poor characteristics.

[Effect of the Invention] A film made of a blend resin of an aromatic polyamide and a soluble resin obtained by the present invention does not flow even at a temperature higher than the softening pour point of the soluble resin, has a small heat shrinkage at a high temperature, and has a small dimensional stability. And the characteristics of the capacitor obtained from this film are very good. In addition, it has excellent mechanical properties, particularly tensile elongation and tensile strength, as compared with a single film of a soluble resin, and can be easily handled and processed in the case of a thin material required for a capacitor application. Further, the characteristics of humidity (particularly hygroscopicity), which is said to be the greatest drawback of the aromatic polyamide, are improved, and since it has a fusion property, it has a very large effect when used as a capacitor.

Further, since a relatively inexpensive soluble resin is used, the production cost of the film can be reduced, and the capacitor can be manufactured at low cost.

It is also useful as a variable condenser dielectric, a transformer insulator, an insulator for various motors, a coil insulator, a base of a flexible printed circuit board, and the like.

Furthermore, if the surface properties of the film are within the above-mentioned preferred ranges, the surface will not be scratched by rubbing during processing, and in the case of the same film, there will be little variation in the dielectric constant. Therefore, when used for a capacitor, a capacitor having a small variation in capacitance and a small withstand voltage failure rate can be obtained.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H01G 4/00-4/40

Claims (1)

(57) [Claims] 1. A dielectric film comprising a blend resin of an aromatic polyamide and a soluble resin, wherein the amount of the aromatic polyamide is in the range of 5% by weight to 90% by weight of the blended resin. Heat resistant capacitor.