JPH07120489B2 - Polypropylene resin film for dielectric material and metal vapor deposition film for capacitor using the film - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polypropylene resin film used as a dielectric in obtaining a metal vapor deposited film for a capacitor, and a metal vapor deposited film for a capacitor obtained by using the polypropylene resin film. Regarding

[0002]

2. Description of the Related Art Polypropylene resin films are widely used as dielectrics in the production of capacitors because they have excellent mechanical and electrical properties.

A capacitor having a polypropylene resin film as a dielectric is, for example, wound with a polypropylene resin film and an aluminum foil, or
It is formed by winding a metal vapor deposition film obtained by vapor-depositing a metal such as aluminum or zinc on a polypropylene resin film. A large number of winding and unwinding steps are required for the slitting step, the element winding step, and the like.

On the other hand, in recent years, various machines used for manufacturing capacitors, such as metal vapor deposition machines, narrow width cutting machines, and element winding machines, have been speeded up to cope with high productivity. In addition, a thin polypropylene resin film is used as a dielectric in a capacitor to be produced so as to cope with the miniaturization of the capacitor.

In particular, the thickness 1 which has a problem in working characteristics
In a winding process and a rewinding process of a thin polypropylene resin film having a thickness of 5 μm or less or a metal vapor deposition film having a metal vapor deposition layer formed on the film, meandering or wrinkling occurs in the polypropylene resin film or the metal vapor deposition film. And the deviation of the cross section of the small winding roll or the end face of the capacitor element is likely to occur, which is a factor that reduces the production rate of the metal vapor deposition film and the capacitor using the same.

For this reason, as a dielectric made of a thin polypropylene resin film, for example, a material having a roughened surface or a material subjected to a weak corona discharge treatment has a high-speed winding aptitude. A polypropylene resin film is known.

On the other hand, in polypropylene resin films used for general packaging, it is a very ordinary technical means to improve the slipperiness of the film by incorporating various organic or inorganic fine particles. Although widely used as a polypropylene resin film containing organic or inorganic fine particles, micro voids may occur between the resin and the organic or inorganic fine particles during the stretching process of the polypropylene resin film. , The added fine particles themselves may be made of a conductive metal compound, and the fine particles may contain metals, metal compounds, chlorine compounds, etc. Polypropylene resin film used for general packaging polypropylene The technique of including various organic or inorganic fine particles that are used as sliding property improving means Len resin film was not to be considered at all.

A method for improving the running characteristics of a film by adding a fine powder of a silicone resin is described in, for example, JP-A-62-233248 and JP-A-62-25930.
No. 4, Japanese Patent Laid-Open No. 2-41344 and the like.

That is, Japanese Patent Laid-Open No. 62-233248 discloses a base material layer containing a propylene polymer as a main component,
In a biaxially stretched film comprising a coating resin layer laminated on at least one surface of the base material layer, the coating resin layer is
A laminated film formed of a propylene-ethylene-butene-1 copolymer containing a silicone resin fine powder has been described, but this laminated film is intended to obtain high-speed automatic packaging suitability. Thus, there is no mention in JP-A-62-233248 of the fine powder of silicone resin used in the present invention, which powder has special requirements.

Further, Japanese Unexamined Patent Publication (Kokai) No. 62-259304 describes a film for a capacitor dielectric, which is composed of a polyester resin film containing fine silicone resin powder. This film is a single layer polyester resin. Since the film contains fine particles of silicone resin, the original characteristics of the resin film are likely to be impaired, and the electrical characteristics required for the film to be used as a capacitor dielectric Becomes worse.
Further, as for the silicone resin fine powder having a special regulation as used in the present invention, it is disclosed in JP-A-62-2593.
Nothing is described in the 04 publication.

Further, the laminated film described in JP-A-2-41344 has a resin layer made of a resin composition in which a silicone resin fine powder and a hydroxy fatty acid glyceride are blended in a propylene polymer. However, this laminated film is described as a packaging material, and no reference is made to JP-A-2-41344 regarding a silicone resin fine powder having a special regulation used in the present invention.

[0012]

In the conventional polypropylene resin film used for the above-mentioned use as a dielectric of a capacitor, the surface roughness of the surface due to unevenness improves the slipperiness. It is limited to those that are roughened by utilizing nearby crystal transformations, and roughening by fibrillated mesh-like or independent circular irregularities formed by stretching is used.

The roughening of the polypropylene resin film is carried out by controlling the generation of crystals by utilizing the temperature gradient etc. when the molten resin is crystallized, and therefore the polypropylene resin itself The formation and growth of crystals change depending on the nature of and the subtle temperature change. Therefore, the surface roughening that is formed is unstable, and it is not possible to obtain slipperiness that can sufficiently cope with high-speed running and high-speed winding, and the crystallization time is related to the roughening of the film. Therefore, there is a limit to speeding up the film production.

Further, in the above-mentioned roughened polypropylene resin film, since the roughening is caused by the unevenness due to the crystal transformation generated in the original fabric, the actual thickness in the concave portion of the film becomes small and the insulation resistance is reduced. Has a drawback that the capacitance change of the capacitor becomes large as the value decreases.

On the other hand, the polypropylene resin film imparted with the suitability for high-speed winding by a weak corona discharge treatment or the like is one which prevents the winding deviation by imparting an electric charge to the surface of the film. It has the drawback of being difficult to control the process.

Providing a polypropylene resin film with good suitability for high-speed running by imparting sufficient electric charge by corona discharge treatment or the like has a disadvantage that blocking tends to occur in the film.

On the other hand, the present invention, by adding inorganic or organic fine particles, which has never been considered in the field of polypropylene-based resin films for dielectrics, has a thin thickness of 15 μm or less. In order to impart high-speed running suitability to the polypropylene-based resin film, there is no occurrence of meandering or wrinkles in the winding and rewinding processes of the polypropylene-based resin film or the metallized film, and the cross section of the small roll or A polypropylene-based resin film for a dielectric material, which does not cause displacement on the end face of a capacitor element and has stable slipperiness that can sufficiently correspond to high-speed production of capacitors, and a capacitor using the film An object is to provide a metal vapor deposition film.

[0018]

The first aspect of the present invention comprises a polypropylene resin film provided for use as a dielectric, and a base material layer made of the polypropylene resin film and at least the base material layer. It has a laminated structure with a coating resin layer formed on one surface, and the total thickness of the base material layer and the coating resin layer laminated on the base material layer is 15 μm.
It consists of the following thin films.

The coating resin layer in the polypropylene resin film of the first aspect of the present invention is such that the total content of the metal and the metal-containing compound and the content of chlorine are both 100 ppm with respect to 100 parts by weight of the polypropylene resin. A spherical silicone resin fine powder or silicon dioxide fine powder having the following average particle diameter of 0.1 to 5.0 μ was used in an amount of 0.05 to 2.
The resin composition contained in an amount of 0 parts by weight is formed so that the total thickness of the coating resin layer is 42% or less of the thickness of the base material layer made of the polypropylene resin film.

The metal vapor deposited film for capacitors of the second aspect of the present invention is a metal vapor deposited film in which a metal vapor deposition layer is formed on at least one side of the polypropylene resin film of the first aspect of the present invention.

In the polypropylene resin film for dielectrics of the present invention having the above-mentioned constitution, the polypropylene resin used for the base material layer and the coating resin layer is polypropylene homopolymer, a copolymer of α-olefin and polypropylene. Further, it is a mixed resin of these, and the resin of the base material layer and the resin of the coating resin layer may be the same or different.

The silicone resin fine powder or silicon dioxide fine powder added to the coating resin layer has an average particle diameter of 0.1 to 0.1.
It has a spherical shape of 5.0 μ.

The spherical silicone resin fine powder is composed of a three-dimensional polymer having a siloxane bond as a skeleton.
It is obtained by subjecting a product obtained by hydrolyzing a hydrolyzable silane to a condensation reaction to grow fine particles while forming a siloxane bond. Further, the true spherical silicon dioxide fine powder is obtained by firing the true spherical silicone resin fine powder as it is in air at 200 to 800 ° C. for 2 to 10 hours.

The silicone resin fine powder and silicon dioxide fine powder added to the above-mentioned coating resin layer have a total content of metal and metal-containing compound of 100 ppm or less and chlorine content of 100 ppm or less. Things are used.

That is, the silicone resin fine powder and the silicon dioxide fine powder used in the coating resin layer of the present invention are, for example, those which do not use a metal catalyst in the polymerization of siloxane. It is necessary to make a selection, and it is not possible to directly use silicon dioxide fine powder which is widely used as an additive for conventional general polypropylene resin films for packaging.

The silicone resin fine powder and silicon dioxide fine powder added to the coating resin layer have an average particle size of 0.1 μm.
When the average particle size is less than 5 μm, the sliding property of the coating resin layer obtained by adding these fine powders is not sufficiently improved, and when the average particle size exceeds 5 μ, it is present on the surface portion of the coating resin layer. The average particle size is 0.1 to 5 μm, preferably because the projections of the fine powder may damage the film or cause the fine powder to emboss the other surface of the film in a wound state. Is 0.5-2.5μ
Stuff is used.

Further, the total amount of the silicone resin fine powder and the silicon dioxide fine powder in the coating resin layer is 0.0 with respect to 100 parts by weight of the polypropylene resin in the coating resin layer.
When the amount is less than 5 parts by weight, the sliding property of the coating resin layer is not sufficiently improved, and when the amount is more than 2.0 parts by weight, the electrical properties of the obtained polypropylene resin film are deteriorated. Therefore, the silicone resin fine powder and the silicon dioxide fine powder in the coating resin layer are the same as the polypropylene resin 10
The total amount of these fine powders is 0.05 to 0 parts by weight.
It is used in an amount of 2.0 parts by weight, preferably 0.1 to 1.0 parts by weight.

In the coating resin layer composed of the polypropylene resin layer containing the spherical silicone resin fine powder or silicon dioxide fine powder, a void between the polypropylene resin and the fine powder accompanying the stretching of the polypropylene resin film is formed. Since it is impossible to completely eliminate the generation of, it is preferable to make the thickness of the coating resin layer as thin as possible.
If the thickness of the coating resin layer is less than 0.3 μm, a uniform coating resin layer cannot be obtained. Further, when the thickness of the coating resin layer formed of the polypropylene resin layer containing the silicone resin fine powder or the silicon dioxide fine powder exceeds 42% of the thickness of the polypropylene resin film forming the base material layer, it is obtained. Insulation resistance of the polypropylene resin film to be used is lowered. Therefore, the total thickness of the coating resin layers is 42% or less of the thickness of the polypropylene resin film forming the base material layer, and the coating resin layer on one side of the base material layer is 0.3 μm or more in thickness. Is formed.

The composition of the polypropylene resin and the fine powder used for forming the coating resin layer containing the silicone resin fine powder or the silicon dioxide fine powder can be adjusted, for example, by adding a high concentration of fine particles to the polypropylene resin. A method of adding a masterbatch containing powder and pelletizing it,
Alternatively, it is carried out by a method of pelletizing a polypropylene resin containing a predetermined content of silicone resin fine powder or silicon dioxide fine powder.

The polypropylene resin film forming the base material layer and the coating resin layer are laminated by coextrusion molding of the two or by extruding and laminating the coating resin layer on a uniaxially stretched polypropylene resin film. It is done by doing.

The polypropylene resin film forming the base material layer is stretched at 120 to 160 ° C.
~ 7 times, about 7 to 12 times at 140 to 170 ° C in the horizontal direction, and then 5 to 140 times at 140 to 170 ° C in the horizontal direction.
Relaxation heat treatment of about 15% is performed. The stretching treatment is the same as in the case of obtaining an ordinary stretched polypropylene-based resin film.

In the polypropylene-based resin film for dielectrics of the present invention, prior to the formation of the metal vapor deposition layer on the film, the surface on which the metal vapor deposition layer is to be formed is subjected to adhesion improving treatment such as corona discharge treatment. It is preferable to attach it.

The polypropylene-based resin film for a dielectric of the present invention having the above-described structure is a means for improving the sliding property of a conventional polypropylene-based resin film for a dielectric, that is, a crystal formed on a raw material. By roughening the surface due to the irregularities associated with the transformation, or by using it together with a means for imparting an electric charge to the surface of the film by, for example, a weak corona discharge treatment, a film having a more excellent sliding property can be obtained.

[0034]

EXAMPLES Hereinafter, the concrete constitutions of the polypropylene resin film for dielectrics of the present invention and the metal vapor deposition film for capacitors using the film will be described with reference to production examples.

Example 1 A compounding composition for a base material layer made of an isotactic polypropylene homopolymer (MFR 1.8 g / 10 minutes) containing an antioxidant, and an isotactic polypropylene homopolymer (MFR 1.8 g / Mg). 10 minutes) 100 parts by weight and 0.3 parts by weight of spherical silicone resin fine powder having an average particle diameter of 2.0μ (total content of metal and metal-containing compound: 56 ppm, chlorine content: 22 ppm) By using the compounding composition for the coating resin layer according to 1. above, these compounding compositions are respectively extruded by separate extruders, integrated by a T-die for co-extrusion, and then molded by a 40 ° C. cast roll. , The resin layer for the coating resin layer having a thickness of 20 μ has a thickness of 200
A 240 μ three-layered original fabric was obtained, which was laminated on and under the μ base resin layer.

The obtained raw fabric is subjected to 12 by the roll stretching method.
It is stretched 5 times in the machine direction at 5 ° C, and subsequently stretched 10 times in the transverse direction at 160 ° C by a tenter stretching method.
After performing a heat treatment to give a shrinkage of 7% at 165 ° C.,
By subjecting one side of the film to corona discharge treatment, a coating resin layer having a thickness of 0.5 μ is laminated on both upper and lower surfaces of a base material layer made of a polypropylene resin film having a thickness of 4 μ. A polypropylene resin film [a] for a dielectric having a three-layer structure was obtained.

The wetting tension of the corona discharge treated surface (preferred metallization surface) of the polypropylene resin film [a] is 38 dyne / cm 2.

Example 2 Instead of 0.3 part by weight of a true spherical silicone resin fine powder having an average particle size of 2.0 μ in Example 1, an average particle size of 0.8 μ was used.
True spherical silicone resin fine powder (total content of metal and metal-containing compound: 48 ppm, chlorine content: 28 pp
A polypropylene-based resin film [b] having a three-layer structure for a dielectric was obtained by using 0.5 part by weight of m 2) and following the same procedure as in the corresponding procedure of Example 1.

Example 3 Instead of 0.3 part by weight of spherical silicone resin fine powder having an average particle size of 2.0 μ in Example 1, an average particle size of 4.5 μ was used.
True spherical silicone resin fine powder (total content of metal and metal-containing compound: 63 ppm, chlorine content: 34 pp
A polypropylene-based resin film [c] having a three-layer structure for a dielectric was obtained by using 0.2 parts by weight of m 2) and following the same procedure as in the corresponding procedure of Example 1.

Example 4 Instead of 0.3 part by weight of the spherical silicone resin fine powder having an average particle size of 2.0 μ in Example 1, the spherical silicone resin fine powder used in Example 1 [metal and Total content with metal-containing compounds: 56ppm, chlorine content: 22ppm
] A spherical spherical silicon dioxide fine powder having an average particle size of 1.6 μ obtained by firing in air at 500 ° C. for 4 hours (total content of metal and metal-containing compound 37
ppm, chlorine content 11 ppm) 0.3 parts by weight,
Following the same recipe as the corresponding procedure of Example 1 above,
A polypropylene resin film [d] for a dielectric having a three-layer structure was obtained.

Example 5 Using the compounding composition for the base layer and the compounding composition for the coating resin layer used in Example 1 respectively, these compounding compositions were extruded by different extruders, After being integrated with a T-die for co-extrusion, by molding with a cast roll at 40 ° C., a resin layer for a base material layer having a thickness of 230 μ,
A 20-μm-thick resin layer for coating resin layer laminated on one surface of the resin layer for base material layer to obtain an original fabric having a two-layer structure.

The obtained raw fabric was treated in the same manner as in the corresponding procedure of Example 1 to prepare a substrate layer made of a polypropylene resin film having a thickness of 4.5 μ, and one side of the substrate layer. A polypropylene resin film [e] for a dielectric having a two-layer structure having a 0.5 μm thick coating resin layer laminated on the above was obtained.

Example 6 Using the compounding composition for the base layer and the compounding composition for the coating resin layer used in Example 1, the compounded compositions were extruded by different extruders, After being integrated with a T-die for co-extrusion, the resin layer for a coating resin layer with a thickness of 20μ is for a base material layer with a thickness of 200μ by being gradually cooled by a 90 ° C cast roll to be crystallized and molded. An original fabric having a three-layer structure laminated on and below the resin layer was obtained.

The obtained original fabric was rolled by a roll stretching method to obtain 14
Stretched 5 times in the machine direction at 8 ° C., then stretched 10 times in the transverse direction at 160 ° C. by a tenter stretching method, and further,
After performing a heat treatment to give a shrinkage of 7% at 165 ° C.,
By subjecting one side of the film to corona discharge treatment, a coating resin layer having a thickness of 0.5 μ is laminated on each of the upper and lower base layers made of a polypropylene resin film having a thickness of 4 μ. Polypropylene resin film for dielectrics having a three-layer structure with both surfaces roughened [f]
Got

The polypropylene resin film [f]
Is a polypropylene resin film whose surface is roughened by controlling the generation of crystals by utilizing the temperature gradient etc. when the molten resin is crystallized when manufacturing the original fabric. Is.

Example 7 A non-corona discharge treated surface of the polypropylene resin film [a] having a three-layer structure obtained in Example 1 was subjected to weak corona discharge treatment, and the wetting tension of the surface was 31.5 dyne / cm 3
A polypropylene resin film [g] having a layered structure for a dielectric was obtained.

Comparative Example 1 In place of 0.3 part by weight of the spherical silicone resin fine powder having an average particle size of 2.0 μ in Example 1, 0.03 part by weight of this spherical silicone resin fine powder was used. Example 1 below
According to the same procedure as the corresponding procedure in 1., a polypropylene-based resin film for a dielectric having a three-layer structure for comparison [A]
Got

Comparative Example 2 2.5 parts by weight of this spherical silicone resin fine powder was used in place of 0.3 part by weight of the spherical silicone resin fine powder having an average particle size of 2.0 μ in Example 1. Then, a polypropylene resin film [B] for comparison having a three-layer structure for a dielectric was obtained by the same formulation as the corresponding procedure of Example 1 below.

Comparative Example 3 Using the composition for the base layer and the composition for the coating resin layer used in Example 1, a resin layer for the coating resin layer having a thickness of 40 μ and a thickness of 160 μ was used. An original fabric having a three-layer structure, which is laminated on and under the resin layer for a base material layer, was obtained.

The obtained raw fabric was subjected to the same formulation as in the corresponding procedure of Example 1 below, and a coating resin layer having a thickness of 1 μ was laminated on the base layer having a thickness of 3 μ, respectively. A polypropylene-based resin film [C] for a dielectric having a three-layer structure for comparison was obtained.

Comparative Example 4 Instead of 0.3 part by weight of the true spherical silicone resin fine powder of Example 1, the total content of metal and metal-containing compound was 1200 ppm, and the chlorine content was 250 ppm. Using 0.3 part by weight of fine powder of synthetic silicon dioxide having an average particle diameter of 2.2μ, and following the same procedure as the corresponding procedure of Example 1, a polypropylene resin for dielectrics having a three-layer structure for comparison. A film [D] was obtained.

Comparative Example 5 100 parts by weight of the compounded composition for the base material layer of Example 1 and a true spherical silicone resin fine powder having an average particle size of 2.0 μ (total content of metal and metal-containing compound: 56 ppm, Chlorine content 2
2 ppm) 0.3 part by weight was extruded from a T-die of an extruder and molded by a cast roll at 40 ° C. to obtain a raw sheet having a thickness of 250 μ.

By subjecting the obtained original fabric to the same procedure as the corresponding procedure of Example 1 below, a polypropylene-based resin film [E] for a dielectric for comparison of a single layer structure having a thickness of 5 μm [E] Got

Comparative Example 6 The compounding composition for the base layer of Example 1 was extruded with a T-die of an extruder, gradually cooled with a 90 ° C. cast roll, and molded to crystallize the surface to obtain a thick film. A raw fabric of 250 μm was obtained.

The obtained original fabric was rolled by a roll stretching method to obtain 14
Stretched 5 times in the machine direction at 8 ° C., then stretched 10 times in the transverse direction at 160 ° C. by a tenter stretching method, and further,
After performing a heat treatment to give a shrinkage of 7% at 165 ° C.,
By subjecting one side of the film to corona discharge treatment, the wetting tension of the corona discharge treated surface (planned metallization surface) is 38 dyne.
A polypropylene-based resin film [F] for a dielectric having a roughened surface for comparison with a single layer structure having a thickness of 5 μm / cm 2 was obtained.

In the polypropylene-based resin film [F], when producing a raw material of the polypropylene-based resin film, the temperature gradient when the molten resin is crystallized is used to control the formation of crystals. As a result, the surface is roughened based on the crystal transformation near the surface.

Comparative Example 7 An isotactic polypropylene homopolymer containing the antioxidant used in the base material layer of Example 1 was extruded with a T die of an extruder and molded with a 40 ° C. cast roll. After obtaining an original fabric having a thickness of 250 μm, the original fabric was subjected to the same procedure as the corresponding procedure of Example 1 to obtain a polypropylene resin film having a single layer structure and a thickness of 5 μm.

Subsequently, a weak corona discharge treatment was applied to the non-corona discharge treated surface of this polypropylene resin film, and the wetting tension of the surface was 31.5 dyne / cm. A film [G] was obtained.

[Experiment 1] The electrical properties of the polypropylene resin films of Examples 1 to 7 and Comparative Examples 1 to 7 described above were shown by an insulation defect test and a dielectric breakdown strength test.

According to JIS C 2330, the insulation defect test was carried out in accordance with JIS C 2330 at a location where a DC charge of 1.5 KV was applied to a gap of 50 μ, and 50 m of each roll film for experiment having a width of 640 mm and a length of 20,000 m. Only a length of 500 m of the film was passed at a speed of / min., and the number of dielectric breakdowns (number / m ² ) generated in the film was shown.

The dielectric breakdown strength (KV) is JIS C 2330.
The average value and the minimum value of the dielectric breakdown strength obtained based on The results are shown in [Table 1].

[0062]

[Table 1]

Examples 8 to 14, Comparative Examples 8 to 14 Width 640 mm and length 20000 m according to the polypropylene resin films of Examples 1 to 7 and Comparative Examples 1 to 7 described above.
Aluminum film was vapor-deposited on the corona discharge treated surface (planned metallization surface) of the roll-up film with a vacuum deposition machine [manufactured by Nippon Vacuum Technology Co., Ltd.], and the metal film resistance value was 3.5 Ω / cm
14 kinds of metal vapor deposition films for capacitors were obtained.

[Experiment 2] Examples 8 to 14 and Comparative Examples 8 to
Using a table bobbin machine (manufactured by Nishimura Seisakusho Co., Ltd.), each of 14 capacitor metal-deposited films was made into a 6 mm film with a width of 100 mm.
Book, 200m / mi, so that it will be 4 wholesales with 5000m length
Slitting was performed at a speed of n. to obtain 24 small rolls each.

The condition of the obtained small winding roll was judged by the wrinkles and the cross-section deviation, and the number of defectives generated in the bobbin slit process was measured. The results are shown in [Table 2].

[Experiment 3] From the small-winding rolls obtained in [Experiment 2], "no defects occurred at the time of bobbin slitting" were extracted to two of the same type, and the automatic element winding machine Dou Seisakusho: 3KAW-4L type], tension 5 kg, element winding speed 3500 rpm and 5000
A capacitor element was prepared at rpm, and the wrinkle state generated on the running film during element winding and the deviation of the end surface of the obtained capacitor element were observed, and the running property of the metal vapor deposition film for capacitors was tested. The results are shown in [Table 2].

The wrinkles that occur in the slitting process using the bobbin and the element winding process using the element winding machine and the deviation that occurs on the end surface of the capacitor element are more likely to occur as the width of the film increases. In [Experiment 1] and [Experiment 2], 100 mm, which is the widest width of the metal vapor deposition film for capacitors currently produced.
Experimented according to width.

In [Table 2], wrinkles generated during the running of the metal vapor deposition film for capacitors are as follows: ○ ・ ・ ・ ・ No wrinkles at all △ ・ ・ ・ ・ From less than 50 turns from the beginning of winding No wrinkles were observed (Pass judgment) × ・ ・ ・ ・ Wrinkles were observed even after 50 turns from the beginning of winding XX ・ ・ ・ ・ Wrinkles were observed during winding.

Regarding the displacement of the end faces of the obtained capacitor element, ○: No displacement occurred at all △: Displacement of less than 1 mm occurred (pass judgment) ×・ ・ ・ Difference of 1 mm or more and less than 5 mm has occurred XX ・ ・ ・ ・ Displayed with a deviation of 5 mm or more.

[0070]

[Table 2]

From the results of [Table 1] and [Table 2], (1) When the amount of the silicone resin fine powder or silicon dioxide fine powder mixed in the coating resin layer is small, the film winding suitability is determined. No improvement can be obtained. [Comparative Example 8] (2) Sufficient improvement effect can be obtained by the conventional winding roughening treatment such as surface roughening or weak corona discharge treatment on the back surface of polypropylene resin film for dielectrics. I can't. [Comparative Examples 13 and 14] (3) When a sufficient amount of the silicone resin fine powder or silicon dioxide fine powder is mixed in the coating resin layer, the film winding aptitude can be improved, If the mixing amount of the silicone resin fine powder or the silicon dioxide fine powder is too large, the insulation resistance decreases. [Comparative Example 2] (4) When the silicone resin fine powder or the silicon dioxide fine powder is mixed in all layers or when the thickness of the coating resin layer is increased, the insulation resistance is deteriorated and the coating resin layer The thinner the film, the better the properties as a polypropylene resin film for dielectrics. [Comparative Example 5], [Comparative Example 3] (5) In the case where the coating resin layer is formed on one side of the base material layer and the case where it is formed on both sides, the latter is slightly more suitable for winding. Good properties are obtained. [Embodiment 8], [Embodiment 12] (6) Metals and metal-containing compounds, chlorine, etc., contained in the silicone resin fine powder or silicon dioxide fine powder adversely affect the insulation resistance. [Comparative Example 4] (7) A film having a coating resin layer containing a silicon dioxide fine powder obtained by firing a silicone resin fine powder is
Compared with a film having a coating resin layer containing fine silicone resin powder, a more excellent effect in terms of insulation resistance is exhibited. [Examples 1 and 4] (8) When the treatment for improving the winding aptitude, which has been performed on the conventional polypropylene-based resin film for a dielectric, is used together with the coating resin layer surface, the winding aptitude is improved. Further improvements are planned. The facts such as [Example 13] and [Example 14] can be confirmed.

[0072]

The polypropylene resin film for dielectrics according to the first aspect of the present invention comprises a base material layer made of a polypropylene resin film and a coating resin layer formed on at least one side of the base material layer. The coating resin layer has an average particle size of 0.1 to 5.0 μm with respect to 100 parts by weight of the polypropylene resin, and the total content of the metal and the metal-containing compound and the content of chlorine are both 100 ppm. The following spherical silicone resin fine powder or silicon dioxide fine powder,
With the resin composition contained in a proportion of 0.05 to 2.0 parts by weight, the total thickness of the coating resin layer is 42% of the thickness of the base material layer.
It is formed as a resin layer having the following thickness, and the total thickness of the base material layer made of a polypropylene resin film and the coating resin layer laminated on the base material layer is 15 μm or less. .

The polypropylene-based resin film for a dielectric of the first aspect of the present invention having the above-mentioned structure is considered in the field of conventional polypropylene-based resin film for a dielectric as it leads to deterioration of electrical characteristics. The improvement of running suitability due to the addition of organic fine powder or inorganic powder, which has never been seen, is brought to a thin film with a thickness of 15 μ or less, and organic fine powder or inorganic powder under special conditions can be used in a special state. By using it, it does not deteriorate the electrical properties displayed in the insulation defect test and the dielectric breakdown strength test, and is equipped with running suitability that can withstand high-speed production,
The production of good quality capacitor elements can be done efficiently.

The metal vapor deposition film for capacitors according to the second aspect of the present invention comprises a metal vapor deposition layer on at least one side of the polypropylene resin film for dielectrics according to the first aspect of the present invention. Since the running characteristics of the coating resin layer of the polypropylene-based resin film are maintained as they are, it is possible to efficiently produce a capacitor element of good quality.

Claims (2)

[Claims] 1. A polypropylene resin film for a dielectric comprising a base material layer made of a polypropylene resin film and a coating resin layer formed on at least one surface of the base material layer, wherein the coating resin layer comprises: The average particle size is 0.1 to 100 parts by weight of polypropylene resin.
A silicone resin fine powder or a silicon dioxide fine powder having a true spherical shape of 5.0 μm and having a total content of metal and metal-containing compound and chlorine content of 100 ppm or less,
A total thickness of a base material layer formed of a polypropylene-based resin film and a coating resin layer laminated on the base material layer, which is formed of a resin composition containing 0.05 to 2.0 parts by weight. Is 15 μm or less, and the total thickness of the coating resin layers is 42% or less of the thickness of the base material layer made of polypropylene resin film. . 2. A metal vapor deposition film for capacitors, comprising the polypropylene resin film for dielectrics according to claim 1 and a metal vapor deposition layer formed on at least one surface of the film.