JP2002110449A - Capacitor and polyester film therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyester film for a bare capacitor having excellent thermal adhesive properties and blocking resistance. SOLUTION: In the thermal adhesive polyester film in which a thermal adhesive resin layer is laminated on at least one surface of a base material film composed of a polyester resin, the thermal adhesive resin layer uses an amorphous polyester copolymer resin and spherical inactive grains as main ingredients, a hydrogen bonding-power component term γsh in the surface free- energy of a thermal adhesive resin layer surface is 5-15 mN/m, and a hydrogen dispersion-force component term γsd is 30-45 mN/m. The inactive grains are compounded with the amorphous polyester copolymer resin of 100 pt.wt. in 1-15 pt.wt.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester film for a capacitor and a capacitor obtained by using the film. More specifically, the present invention relates to a polyester film for a capacitor that does not require an exterior and can provide a wound-type capacitor having excellent long-term moisture resistance and heat resistance.

[0002]

2. Description of the Related Art Conventionally, as a method of packaging a film capacitor, a method of wrapping a capacitor element in a resin by dipping or molding, and a method of storing a capacitor element in a metal or resin container and sealing it, etc. There is known a method of providing an exterior by using a conventional method.

[0003] In recent years, non-exterior capacitors have been developed in which a resin film as a dielectric is provided with an exterior function for the purpose of reducing the weight and size of the capacitor and reducing the cost by reducing the number of manufacturing steps.

[0004] The resin film used in such a non-exterior capacitor is generally formed by forming a heat-adhesive resin layer on a base film. There is a problem that the thermal adhesiveness of the thermal adhesive resin layer is not sufficient, the long-term moisture resistance and heat resistance are poor, the thermal adhesive surface is peeled off, and the capacitance of the capacitor changes. In addition, there is a problem that when the thermal adhesiveness of the adhesive resin is to be improved, blocking of the film roll is likely to occur, and it is difficult to process the film-type capacitor.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and its main object is to provide a non-exterior capacitor in which an exterior function is imparted to a polyester film which is a dielectric. An object of the present invention is to provide a polyester film having excellent heat adhesion and blocking resistance.

[0006]

Means for Solving the Problems The present inventor has made intensive studies to achieve the above object. As a result, in a polyester film for a capacitor in which a heat-adhesive resin layer is laminated on at least one surface of a base film made of a polyester resin, the heat-adhesive resin layer has an amorphous polyester copolymer resin and spherical inert particles. It has been found that when the surface free energy of the surface of the heat-adhesive resin layer is within a specific range, a polyester film for a capacitor that can achieve the above-mentioned object can be obtained. The invention has been completed.

That is, the present invention provides the following polyester film for a capacitor and a capacitor. 1. A heat-adhesive polyester film in which a heat-adhesive resin layer is laminated on at least one surface of a base film made of a polyester resin, wherein the heat-adhesive resin layer contains an amorphous polyester-based copolymer resin and spherical inert particles. The hydrogen bonding force component term γsh in the surface free energy of the surface of the thermoadhesive resin layer is 5 to 15 mN / m as a main component.
And a hydrogen dispersing power component term γsd of 30 to 45 mN / m, and 1 to 15 parts by weight of the inactive particles are mixed with 100 parts by weight of the amorphous polyester copolymer resin. For polyester film. 2. A heat-adhesive resin layer is formed by a coating method, and the dry-coating amount of the heat-adhesive resin layer laminated on the base film is 0.
1 g / m ² was to 2.0 g / m ^2, and a polyester film for capacitor according to Item 1, wherein the thermal bonding initiation temperature due to the thermal gradient measuring device is 80 to 120 ° C.. 3. Item 3. The polyester film for a capacitor according to Item 1 or 2, wherein the inert particles are silicon dioxide particles. 4. The substrate film according to any one of items 1 to 3, wherein the substrate film is a biaxially stretched film of a polyester resin, and the substrate film contains 100 to 300 ppm of antimony trioxide as an antimony element. Polyester film for condenser. 5. The thickness of the heat-adhesive polyester film is 3 to 30
Item 5. The polyester film for a capacitor according to any one of Items 1 to 4, which has a size of μm. 6. Haze value of thermal adhesive polyester film is 5%
Item 6. The polyester film for a capacitor according to any one of Items 1 to 5, above. 7. The polyester film for a capacitor according to any one of the above items 1 to 6, and a metal foil or a metal-deposited plastic film are stacked so that the heat-adhesive resin layer of the polyester film is in contact with the metal foil or the metal-deposited surface. Winding type condenser obtained by winding up and heat pressing.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The polyester film for a capacitor of the present invention is obtained by laminating a heat-adhesive resin layer on at least one surface of a base film made of a polyester resin.

[0009] Polyester resins used as the base film substrate film is a crystalline thermoplastic resin which is polymerized by an ester bond is usually obtained by polycondensation of a dicarboxylic acid component and a glycol component.

The dicarboxylic acid component constituting the polyester resin includes terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, cyclohexanedicarboxylic acid, diphenylethanedicarboxylic acid and the like. Examples of the glycol component include ethylene glycol, propylene glycol, tetramethylene glycol, cyclohexanedimethanol and the like. Preferred dicarboxylic acid components are terephthalic acid, naphthalene-2,6-dicarboxylic acid and the like, and preferred glycol components are ethylene glycol and the like.

Among the polyester resins used for the base film, preferred are polyethylene terephthalate, polyethylene-2,6-naphthalate, poly-1,
4-cyclohexane dimethylene terephthalate and the like. These preferable polyester resins further include, if necessary, in addition to the dicarboxylic acid component and the glycol component constituting the polyester resin, the aforementioned dicarboxylic acid component or the glycol component in an amount of 30 mol% of the monomer component constituting the polyester resin. It may be obtained using the following range, preferably 15% by mole or less. Alternatively, a polyester resin other than the above-mentioned preferred polyester resin may be mixed and used.

The polyester resin constituting the base film is preferably obtained by using antimony trioxide as a polymerization catalyst. The amount of the polyester resin used is 100 ppm to 300 ppm as an antimony element in the polyester resin.
It is suitable that the amount is contained, preferably about 120 ppm to 240 ppm.

Usually, the higher the intrinsic viscosity of the polyester resin, the better the voltage resistance, mechanical properties, long-term moisture resistance, heat resistance, etc., and the intrinsic viscosity is about 0.5 dl / g or more, preferably 0.6 dl / g. / G or more is suitable. Also,
If the intrinsic viscosity is less than 0.5 dl / g, it becomes difficult to form a film by extrusion melting. If the amount of antimony as a polymerization catalyst is less than 100 ppm, the resulting polyester resin is not preferred because the intrinsic viscosity tends to be less than 0.5 dl / g.

On the other hand, if the amount of antimony exceeds 300 ppm, the amount of impurities and foreign substances generated is large, and insulation failure is likely to occur as a dielectric of the capacitor, which is not preferable.

Heat Adhesive Resin Layer In the capacitor film of the present invention, the heat adhesive resin layer laminated on at least one surface of the polyester resin base film is formed of an amorphous polyester copolymer resin.

The amorphous polyester copolymer resin is a resin polymerized by an ester bond.
A resin having no crystallinity, which is obtained by polycondensation of a dicarboxylic acid component and a glycol component, and is obtained by using two or more types of one or both of the dicarboxylic acid component and the glycol component.

Among the constituent components of the amorphous polyester copolymer resin, examples of the dicarboxylic acid include adipic acid, sebacic acid, trimellitic acid and the like in addition to the dicarboxylic acid usable in the polyester resin for a base film described above. Can be used. As the glycol component, in addition to those described above for the polyester resin for the base film, neopentyl glycol, diethylene glycol, an ethylene oxide adduct of bisphenol A, glycerin and the like can be used. These dicarboxylic acid components and glycol components can be used alone or in any combination of two or more in any appropriate amount.

The heat-adhesive resin layer may be formed by mixing two or more amorphous polyester-based copolymer resins at an arbitrary ratio.

In the present invention, the heat-adhesive resin layer has a hydrogen bonding force component term γsh of 5 to 15 mN / m in surface free energy on the surface of the resin layer, and a hydrogen dispersing force component term γsd of 30 mN / m. It needs to be in the range of 〜45 mN / m.

When the surface free energy on the surface of the heat-adhesive resin layer is within the above range, the heat-adhesive resin layer has excellent heat-adhesive properties, and a capacitor having excellent durability can be obtained. it can. When the surface free energy on the surface of the heat-adhesive resin layer is outside the above range, the heat-adhesive resin layer has insufficient heat adhesion, and the heat-adhesive resin layer and the metal-deposited surface of the metal-deposited film, Adhesion between the metal surface of the metal foil and the plastic film becomes insufficient. As a result, for example, at the time of use as a capacitor, peeling of the metal-deposited surface of the metal-deposited film, the metal foil of the metal foil, and the like may occur, and the capacitance of the capacitor may change. In some cases, the outer film may be peeled off, making it impossible to use it as a capacitor.

It is necessary that the thermal adhesive resin layer contains about 1 to 15 parts by weight of spherical inert particles based on 100 parts by weight of the amorphous polyester copolymer resin.
Even when a good heat-adhesive resin layer having the above-mentioned surface free energy is formed by blending spherical inert particles in the heat-adhesive resin layer,
Blocking between films can be effectively prevented.

As the spherical inert particles used in the present invention, the ratio of the major axis to the minor axis is such that the major axis / minor axis = 1 to 1.
Within a range of about 5 and an average particle size of 10 to 500 nm
Are preferred. Further, it is preferable that the variation rate of the major axis of the particles defined by the following formula is within 30%.

Rate of change of particle diameter of major axis (%) = (standard deviation of major axis / average of major axis) × 100 In the specification of the present application, the particle diameter is determined by a scanning electron microscope (Hitachi, Model S-510). Is a value determined by image analysis using an image analyzer (Luzex 2D, manufactured by Nippon Kogaku Kogyo Co., Ltd.) for at least 100 particles. The diameter is the value obtained from the distance between two vertical lines when the image is sandwiched between two vertical lines (horizontal Feret diameter), and the long diameter is the maximum of the distance between any two points on the circumference of the image. (Absolute maximum length), and the minor axis is the value (width) calculated from the shortest distance between two straight lines when an image is sandwiched between two straight lines parallel to the maximum length.

If the amount of the inert particles is less than 1 part by weight, the blocking resistance becomes insufficient, and the winding of the film capacitor becomes difficult. On the other hand, if the amount of the inert particles is 1
If it exceeds 5 parts by weight, the thermal adhesiveness of the thermal adhesive resin layer is undesirably reduced.

Examples of the inert particles include inorganic particles such as silicon dioxide, titanium oxide, calcium carbonate, calcium silicate, barium sulfate, calcium phosphate, aluminum oxide, magnesium oxide, kaolinite, talc, mica, and zeolite, and crosslinked benzoguanamine resin. And organic particles such as styrene resin. Among these, in particular, since silicon dioxide has a refractive index very close to that of the polyester resin used as the base film, for example, a polyester film for capacitors having excellent transparency such as a haze value of 5% or less is required. It is preferable in that it can be obtained.

The above-mentioned amorphous polyester-based copolymer resin may contain other components, for example, a lubricant other than the above-mentioned inert particles, waxes, etc. to such an extent that its performance is not impaired.

Forming a heat-adhesive resin layer in which the hydrogen bonding force component term γsh in the surface free energy is in the range of 5 to 15 mN / m and the hydrogen dispersion force component term γsd is in the range of 30 to 45 mN / m. In order to adjust the combination of the hydrophilic group and the hydrophobic group in the dicarboxylic acid and glycol, which are the constituent components of the amorphous polyester copolymer resin used to form the resin layer, and the proportions thereof are appropriately adjusted. Good. In addition, since the properties and blending amount of the inert particles such as hydrophilicity and hydrophobicity have some influence on the surface free energy of the thermoadhesive resin layer, the type and blending amount of the inert particles to be used is It is necessary to determine the surface free energy of the layer to be within the above range.

It is preferable that the thermoadhesive resin layer has a thermoadhesion initiation temperature measured by a thermogradient in the range of 80 to 120 ° C. When the thermal bonding initiation temperature is within this range, a thermal adhesive resin layer having particularly excellent properties with respect to both blocking resistance and thermal adhesiveness can be obtained. If the thermal bonding initiation temperature is lower than 80 ° C., blocking tends to occur, and in summer, blocking makes it difficult to process for capacitors. On the other hand, when the thermal bonding starting temperature is 120
If the temperature is higher than 0 ° C., it is not preferable because the thermal adhesiveness is reduced and a minute space is formed when the thermal adhesive resin layer and the metal forming the conductor layer of the capacitor are bonded to each other, and dielectric breakdown easily occurs as a capacitor.

Production of polyester film for condenser
Manufacturing Method Hereinafter, an example of a method for manufacturing the polyester film for a capacitor of the present invention will be described.

First, a base film having a predetermined size is prepared using a polyester resin. The method for producing the base film is not particularly limited. For example, the polyester resin is melt-extruded at a temperature higher than the melting point by an extruder, and cooled to a glass transition temperature or lower to obtain an unstretched film. Next, the unstretched film is biaxially stretched in the length direction and the width direction. The stretching method is not particularly limited, and may be a method of simultaneously stretching in the biaxial direction or a method of sequentially stretching in the biaxial direction. The stretching ratio in the length direction and the width direction is preferably about 3 to 5 times, and more preferably about 3.5 to 4 times.

Next, the polyester-based copolymer resin for the heat-adhesive resin layer is dissolved in an organic solvent, and inert particles are added thereto to prepare a heat-adhesive resin layer forming solution. As the organic solvent, toluene, methyl ethyl ketone, ethyl acetate and the like can be used. The amount of the polyester copolymer resin in the solution may be, for example, about 1 to 20% by weight as a solid content.

Next, a solution for forming a heat-adhesive resin layer is applied to the base film. The coating amount is the dry coating amount,
The amount is preferably about 0.1 to ² g / m ² .

The heat-adhesive resin layer is formed on at least one surface of the substrate film. Specifically, depending on the usage of the winding type capacitor as a dielectric film,
What is necessary is just to form on the base film surface which requires thermal adhesiveness.

Thereafter, the film coated with the heat-adhesive resin layer forming solution is dried to obtain a polyester film for a capacitor. Drying may be performed at a temperature at which the organic solvent can be dried and removed until the organic solvent is sufficiently removed. For example, drying may be performed at about 80 ° C. for about 0.5 minutes.

The thus obtained polyester film for a capacitor is wound up by a conventional method,
A slit is performed, which is an operation of cutting and winding into a width suitable for a film for a capacitor.

The polyester film for a capacitor of the present invention has a total thickness of 3 to 3 including the heat-adhesive resin layer.
It is preferably about 0 μm. If the film is too thin, wrinkles are likely to be formed during winding, resulting in poor workability. On the other hand, if the film is too thick, the diameter after winding becomes too large.

Method for Producing a Capacitor The polyester film for a capacitor of the present invention may be prepared , for example, by subjecting the polyester film and a metal foil or a metal-deposited plastic film to a heat-adhesive resin layer of the polyester film and a metal foil or a vapor-deposited film according to a conventional method. The rolled-up capacitor can be obtained by stacking and winding so as to be in contact with the metal that has been made, and then by heating and pressing.

Examples of the metal used for the metal foil or the metal-deposited plastic film forming the conductor layer include aluminum, palladium, zinc, nickel, gold, silver, copper, indium, tin, chromium, and titanium. Typically, aluminum is used. The thickness of the metal foil is preferably about 3 μm to 12 μm (for example, about 6 μm). The thickness of the metal-deposited plastic film is preferably about 3 μm to 12 μm (for example, about 6 μm). Any appropriate plastic film (for example, polyester film) is used as a base material of the metal-deposited plastic film.

The method of manufacturing the capacitor will be described more specifically. For example, an aluminum metal foil having a thickness of 6 μm and / or
Alternatively, the aluminum-deposited polyester film is brought into contact with the heat-adhesive resin layer of the above-mentioned polyester film for a capacitor, and the roll is wound up with a width of about 20 mm to 100 mm. The obtained wound film reel is thermally bonded at a temperature of, for example, about 120 to 200 ° C. and a pressure of about 5 to 10 kgf / cm ^{2 for} about 1 to 5 hours to perform thermal bonding. Next, external electrodes are formed on both end surfaces of the wound film by metal spraying, and a lead wire is welded to the external electrodes to obtain a wound capacitor element.

[0040]

The polyester film for a capacitor of the present invention has excellent heat adhesion and blocking resistance.

By using such a polyester film as a dielectric for a non-exterior capacitor, a blocking trouble can be prevented, and the processability of a wound-type capacitor can be improved. Further, the obtained capacitor has good thermal adhesiveness, excellent long-term moisture resistance and heat resistance, and has good durability.

In particular, when silicon dioxide is used as the inert particles, the transparency of the film is good, which is advantageous in that a defective portion can be easily found at the time of processing the film.

[0043]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited to these Examples.

Example 1 As an amorphous polyester copolymer resin, a polyester copolymer resin having a trade name of Viron RV20SS (solid content of 30% by weight) and a polyester having a trade name of Byron RV30SS (solid content of 30% by weight) were used. Two types of copolymer resins (both manufactured by Toyobo Co., Ltd.) were used, and these were blended so as to have a solid content of 1: 1 and methyl ethyl ketone so that the solid content concentration was 5% by weight. Was dissolved.
Next, spherical silicon dioxide (manufactured by Nissan Chemical Industries, Ltd., trade name: MEK-ST (solid content: 30% by weight, average particle size: 15 nm)) was added to this solution based on 100 parts by weight of the polyester-based copolymer resin. To obtain a thermoadhesive resin layer forming solution by adding 5 parts by weight in terms of solid content.

As a base film, 2 μm thick 12 μm
An axially stretched crystalline polyester film (manufactured by Toyobo Co., Ltd., trade name: E5107, antimony element 1
30 ppm) on one side of the base film,
The above-mentioned solution for forming a heat-adhesive resin layer was applied by a reverse coater and dried at a drying temperature of 100 ° C. to obtain a polyester film for capacitors having a dry coating amount of 0.5 g / m ² .

The polyester film for a capacitor and a 6 μm-thick aluminum-evaporated biaxially stretched polyester film are wound so that the heat-adhesive resin layer and the aluminum-evaporated surface overlap each other, and are wound to a width of 40 mm and an outer diameter of 15 mmφ. Got a reel. This reel is 140 ° C, pressure 5kg
Pressing was performed at f / cm ² for 2 hours, external electrodes were formed on both ends of the external electrodes by metal spraying, and lead wires were welded to the external electrodes to produce a wound-type capacitor element.

The polyester film for a capacitor and the take-up type capacitor element obtained by the above method were measured for physical properties and evaluated for performance by the following methods. The results are shown in Tables 1 and 2 below.

(1) Measurement and evaluation of surface free energy 20 ° C. × 65% using a contact angle meter manufactured by Kyowa Interface Science Co., Ltd.
Under the condition of RH, the contact angles θw and θy between water and methylene diiodide in contact with the surface of the heat-adhesive resin layer of the polyester film
DKQwens et al., From these measurements j
ournal of Applied polymer Science, Vol.13, P.17
According to the method described in 41 to 1747 ('69), γsh (term of hydrogen bonding force component) and γsd (term of hydrogen dispersion force component) of surface free energy were calculated.

(2) Evaluation of Thermal Adhesion Initiation Temperature The thermal adhesive resin coated surface and the non-coated surface of the polyester film on which the thermal adhesive resin layer was formed were joined, and a thermal gradient measuring device (TOYO SEIKI's GRADIENT TYPE HG) was used. -100), the temperature was adjusted from 50 ° C. to 120 ° C. in steps of 10 ° C. with an air pressure of 2 kgf / cm ² and a pressing time of 60 seconds, and thermocompression bonding was performed. The thermocompression-bonded film was taken out of the thermal gradient measuring device, and the thermocompression-bonded film was peeled off by hand.

(3) Evaluation of blocking resistance The polyester film on which the heat-adhesive resin layer was formed
m × 5 cm, and the coated surface and uncoated surface of the heat-adhesive resin were applied with a load of 25 kgf, left in a hot air drier at 60 ° C. for 24 hours, and the film with the coated and uncoated surfaces was bonded. I took it out. 2.5c width of laminated film
m, and was peeled at a speed of 200 mm / min using Tensilon (RTM-100, manufactured by Toyo Boardwin Co., Ltd.), and the peel strength was measured. The measurement was performed 5 times. When the average peel strength was less than 1 gf / 2.5 cm, ○, 1 gf / 2.
5 cm or more and less than 10 gf / 2.5 cm
/2.5 cm or more was evaluated as x.

(4) Evaluation of Film Haze For the polyester film on which the heat-adhesive resin layer was formed, a haze meter (MODEL TC manufactured by Tokyo Denshoku Co., Ltd.) was used.
-H3DP), and the haze value was measured according to JIS K6714.

(5) Durability of Capacitor In a 65 ° C. × 95% RH atmosphere, a aging was performed by applying a direct current of 20 kV to the take-up type capacitor element, and the electrostatic capacity change rate was measured. Those having an electrostatic capacity change rate ΔC / C after 1000 hours of within ± 8% were judged to have good durability, and those having a rate of change larger than ± 8% were judged to be poor in durability.

Comparative Example 1 Amorphous polyester copolymer resin having a trade name of Byron RV20SS (solid content of 30% by weight) and an amorphous polyester copolymer resin having a trade name of Byron RV30SS (solid content of 30% by weight) (All manufactured by Toyobo Co., Ltd.) were blended so that the solid content was 1: 1 (weight ratio), and the solid content was changed to 1: 1 solution of toluene and methyl ethyl ketone such that the solid content concentration became 5% by weight. Dissolved. Next, amorphous silicon dioxide (trade name: Sylysia 430, manufactured by Fuji Silysia K.K., average particle size: 2.5 μm) was added to this solution in terms of solid content based on 100 parts by weight of the polyester-based copolymer resin. The solution was added so as to be in parts by weight to prepare a solution for forming a heat-adhesive resin layer.

Using this solution for forming a heat-adhesive resin layer, a polyester film for a capacitor was produced in the same manner as in Example 1.

Further, a roll-up type capacitor element was produced in the same manner as in Example 1 using the obtained polyester film for a capacitor.

With respect to the polyester film for a capacitor and the take-up type capacitor element obtained by the above method, physical properties were measured and performance was evaluated in the same manner as in Example 1. The results are shown in Tables 1 and 2 below.

Comparative Example 2 Water-dispersed polyester copolymer resin (manufactured by Toyobo Co., Ltd.
(Trade name: Vironal MD-1250 (solid content 30% by weight)) was diluted and dispersed in a 1: 1 (weight ratio) solution of water and isopropyl alcohol so that the solid content was 5% by weight. Next, spherical silicon dioxide (colloidal silica OL (Nissan Chemical Industry Co., Ltd.)
% By weight and an average particle size of 40 nm) were added to 100 parts by weight of the polyester copolymer resin so as to be 0.05 parts by weight in terms of the solid content to prepare a solution for forming a heat-adhesive resin layer. .

Using this solution for forming a heat-adhesive resin layer, a polyester film for a capacitor was produced in the same manner as in Example 1.

Further, using the obtained polyester film for a capacitor, a roll-up type capacitor element was produced in the same manner as in Example 1.

With respect to the polyester film for a capacitor and the take-up type capacitor element obtained by the above method, physical properties were measured and performance was evaluated in the same manner as in Example 1. The results are shown in Tables 1 and 2 below.

Comparative Example 3 Water-dispersed polyester copolymer resin (manufactured by Toyobo Co., Ltd.
(Trade name: Vironal MD-1250 (solid content 30% by weight)) was diluted and dispersed in a 1: 1 (weight ratio) solution of water and isopropyl alcohol so that the solid content was 5% by weight. Next, 5 parts by weight of TB-702 (solid content: 40% by weight) manufactured by Matsumoto Yushi Seiyaku Co., Ltd. was added as an antistatic agent to 100 parts by weight of the polyester copolymer resin. Silicon (manufactured by Nissan Chemical Industries, Ltd., colloidal silica OL (solid content: 30% by weight, average particle size: 40 nm)) was added in an amount of 0.05 part by weight in terms of solid content based on 100 parts by weight of the polyester copolymer resin. Thus, a solution for forming a heat-adhesive resin layer was prepared.

Using this solution for forming a heat-adhesive resin layer, a polyester film for a capacitor was produced in the same manner as in Example 1.

Further, a roll-up type capacitor element was produced in the same manner as in Example 1 using the obtained polyester film for a capacitor.

With respect to the polyester film for a capacitor and the take-up type capacitor element obtained by the above method, physical properties were measured and performance was evaluated in the same manner as in Example 1. The results are shown in Tables 1 and 2 below.

[0065]

[Table 1]

[0066]

[Table 2]

As is clear from the above results, Example 1
The polyester film for capacitors obtained in (1) had good blocking resistance, low haze value, and good transparency. In addition, winding type capacitors obtained using this capacitor film are
Since the adhesion between the heat-adhesive resin layer and the conductive layer was excellent, the durability was good.

On the other hand, the polyester film for a capacitor obtained in Comparative Example 1 was inferior in transparency to the film obtained in Example 1. Further, the wound-type capacitor obtained by using this film had poor heat adhesion and was insufficient in durability.

The polyester films for capacitors of Comparative Examples 2 and 3 had good blocking resistance and a low haze value as in the examples, and had good transparency, but had poor heat adhesion. The durability of the condenser was inferior.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01G 4/32 301 H01G 4/32 301B // B32B 27/36 B32B 27/36 F term (reference) 4F006 AA35 AB35 AB76 BA01 CA08 DA04 4F100 AA20B AA20H AA29A AA29H AK41A AK41B AK41J AL01B AL05 BA02 BA03 BA06 BA10B BA13 CA23A CA23B EH46B EJ38A GB41 JA12B JA13B JB04B JB07 JJ03 JL00 JL01 JL12B JN01 JN02 YY00 YY00A YY00B YY00H 4J002 CF031 CF061 CF081 DE126 GQ00 4J004 AA15 AA18 AB01 AB03 CA06 CC02 EA01 FA05 5E082 AB05 BC19 BC23 EE03 EE07 EE37 FF15 FG06 FG36 FG51 FG54 MM22 MM24 PP03 PP06

Claims (7)

[Claims] 1. A heat-adhesive polyester film in which a heat-adhesive resin layer is laminated on at least one surface of a base film made of a polyester resin, wherein said heat-adhesive resin layer is made of an amorphous polyester-based copolymer resin and a spherical resin. And the hydrogen bonding force component γsh in the surface free energy of the surface of the thermo-adhesive resin layer is 5 to 15 mN / m and the hydrogen dispersing force component γ
sd is 30 to 45 mN / m, and the inactive particles are 1 to 100 parts by weight of the amorphous polyester copolymer resin.
A polyester film for a capacitor, which is blended in an amount of 15 to 15 parts by weight. 2. A heat-adhesive resin layer is formed by a coating method,
Dry coating amount of the heat adhesive resin layer laminated on the base film is ^{0.1g / m 2 ~2.0g / m 2} , and the thermal bonding start temperature due to thermal gradient meter is 80 to 120 ° C. The polyester film for a capacitor according to claim 1, wherein: 3. The polyester film for a capacitor according to claim 1, wherein the inert particles are silicon dioxide particles. 4. The method according to claim 1, wherein the base film is a biaxially stretched film of a polyester resin, and the base film contains 100 to 300 ppm of antimony trioxide as an antimony element. The polyester film for a capacitor according to any one of the above. 5. A heat-adhesive polyester film having a thickness of 3
The polyester film for a capacitor according to any one of claims 1 to 4, which has a thickness of from 30 to 30 µm. 6. The polyester film for a capacitor according to claim 1, wherein the haze value of the heat-adhesive polyester film is 5% or less. 7. The polyester film for a capacitor according to any one of claims 1 to 6, and a metal foil or a metal-deposited plastic film, wherein the heat-adhesive resin layer of the polyester film and the metal foil or the metal-deposited surface are provided. A winding type capacitor obtained by winding and heating and crimping in contact with each other.