JP2002121298A - Polyphenylene sulfide film and capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prepare a polyphenylene sulfide film whose yield in capacitor production is increased, and which is suitable for capacitors having high reliability since voltage endurance is improved while the heat resistance, frequency properties and mechanical properties characteristic to polyphenylene sulfide are kept. SOLUTION: The polyphenylene sulfide film has a surface tension of film of >=40 dyn/cm and a heat sticking-starting temperature of <=150 deg.C. The film surface on the side having no metal membrane is subjected to a corona discharge treatment, a plasma treatment or a primer treatment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyphenylene sulfide film and a capacitor using the same.

[0002]

2. Description of the Related Art A polyphenylene sulfide film (hereinafter sometimes abbreviated as a PPS film) is disclosed in Japanese Patent Application Laid-Open No. 54-142275. Also,
Japanese Patent Application Laid-Open No. 57-187327 proposes using this PPS film as a dielectric of a capacitor to provide a capacitor having excellent heat resistance, frequency characteristics, temperature characteristics, and the like. However, the above-mentioned capacitor has a drawback that the range of manufacturing conditions is narrow in the manufacturing process, that is, in the steps of lamination, winding, cutting, molding, and the like, and when these are insufficiently managed, defective products due to low voltage breakdown increase. was there. Furthermore, the above-mentioned capacitors are often short-circuited without self-healing (self-healing) when low-voltage breakdown occurs, which leads to further disadvantages such as an increase in the rejection rate and low reliability during use. there were.

Conventionally, in order to solve such a problem,
JP-A-4-219236 and JP-A-5-318665 propose that a PPS laminated film in which a polyester resin or a polyolefin resin is laminated on at least one surface of a PPS film is used for a capacitor. However, these PPS laminated films have the following problems.

That is, the conventional PPS laminated film is:
Using a crystalline polymer (polymer having a melting point) such as polyester resin or polyolefin resin,
It is manufactured by a method of melt co-extrusion of this and PPS and co-stretching. As described above, in the method of biaxially stretching the melt-coextruded laminate and heat-treating the polyester resin or polyolefin resin, the melting point of the polyester resin or polyolefin resin is lower than that of PPS. There is.
For this reason, the PPS laminated film has a large heat shrinkage and easily peels off at the interface with PPS because the laminated resin is molecularly oriented. Further, when the heat treatment temperature is higher than the melting point of the laminated resin, the polyester layer and the polyolefin layer are melted and crystallized, resulting in a decrease in mechanical properties and a change in surface roughness of the PPS laminated film, and a decrease in workability of the capacitor. There was a problem. Further, even when a laminated resin such as a polyester resin or a polyolefin resin has a melting point equal to or higher than that of a PPS film, the laminated resin is easily oriented at an interface with PPS due to molecular orientation. Therefore, the range of manufacturing conditions for solving the above-mentioned problems in the conventional PPS laminated film is extremely narrow, and a film of sufficient quality cannot be obtained.

[0005]

The problem to be solved by the present invention is that PP
Provided is a polyphenylene sulfide film that can improve the withstand voltage, which is a problem of PPS film capacitors, without impairing the excellent heat resistance, dielectric properties, mechanical properties, and the like of the S film, and a capacitor using the same. Is to do.

[0006]

Means for Solving the Problems The present invention has the following arrangement to solve the above-mentioned problems. (1) A polyphenylene sulfide film, wherein the film has a surface tension of 40 dyn / cm or more and a thermal adhesion start temperature of 150 ° C. or less. (2) The polyphenylene sulfide film as described in (1) above, wherein the surface of the film on which the metal film is not formed has a surface tension of 40 dyn / cm or more and a thermal adhesion start temperature of 150 ° C. or less. . (3) The polyphenylene sulfide film according to the above (1) or (2), wherein a corona discharge treatment, a plasma discharge treatment, or a primer treatment is applied to a surface of the film on which the metal film is not formed. (4) The polyphenylene sulfide film according to any one of the above (1) to (3), wherein the film thickness is 3 μm or less. (5) A capacitor obtained by winding or laminating a metallized polyphenylene sulfide film obtained by forming a metal film on at least one surface of the polyphenylene sulfide film according to any one of the above (1) to (4). (6) A capacitor obtained by winding or laminating a polyphenylene sulfide film according to any one of the above (1) to (4) and a metallized polyphenylene sulfide film obtained by forming a metal film on both surfaces of the polyphenylene sulfide film.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The PPS film of the present invention is a film obtained by melt-extruding a resin composition containing polyphenylene sulfide as a main component (hereinafter, PPS resin composition), biaxially stretching and heat-treating.

Here, the polyphenylene sulfide film of the present invention has a surface tension of 40 dyn.
/ Cm or more, and a polyphenylene sulfide film characterized by having a thermal adhesion start temperature of 150 ° C. or less.

The surface tension is preferably 45 dyn / cm
Or more, 72 dyn / cm or less, more preferably 60 dy / cm
n / cm or more, 72 dyn / cm or less, more preferably 65 dyn / cm or more, 72 dyn / cm or less;
The thermal adhesion start temperature is preferably 110 ° C. or higher,
The temperature is 40 ° C or lower, more preferably 110 ° C or higher and 130 ° C or lower, further preferably 110 ° C or higher and 125 ° C or lower.

Hitherto, for the purpose of enhancing the easy adhesion when a metal film is formed on the film surface, it has been adopted to increase the surface tension of the film on which the metal film is formed. On the other hand, in the present invention, it is possible to improve the adhesion between the non-metallized film surface and the metallized film surface by setting the surface tension of both surfaces of the film or the film on which the metal film is not formed to the above range. Becomes Therefore, in the processing step of the capacitor, when laminating or winding the film, because the adhesion between the non-metallized film surface and the metallized film surface is improved, it adheres without peeling even at low temperature and low pressure, Since the defective rate of the electrical characteristics can be reduced, productivity is remarkably improved. In the capacitor processing step, as a method of laminating or winding a film, a method of laminating or winding a single-sided metallized film and a method of laminating or winding such that a double-sided metallized film and a non-metallized film are alternately combined. There is a method of turning. On this occasion,
When laminating or winding a single-sided metallized film,
The surface tension of the film on which the metal film is not formed is in the above range, and when laminating or winding a double-sided metallized film and a non-metallized film, the surface tension of both surfaces of the non-metallized film is By setting the range, the adhesion between the metallized film surface and the non-metallized film surface can be improved.

In the present invention, in order to keep the surface tension and the thermal adhesion start temperature in the above ranges, for example, corona discharge is applied to both surfaces of the biaxially oriented polyphenylene sulfide film film or the surface on which the metal film is not formed. Preferably, an easy adhesion treatment such as treatment, plasma treatment, or primer treatment is performed, and more preferably, corona discharge treatment is performed.

In this case, preferable corona discharge treatment methods include EC treatment, NE treatment, and CE treatment. Here, EC treatment refers to surface treatment in an air atmosphere, NE refers to surface treatment in a nitrogen atmosphere, and CE treatment refers to a mixed gas of carbon dioxide and nitrogen. This indicates that the surface treatment is performed.

The strength of the corona discharge treatment is preferably 20 W · min / m ² or more, more preferably 4 W / min / m ² or more.
0 W · min / m ² or more, 100 W · min / m ² or less,
More preferably, 60 W · min / m ² or more, 100 W ·
min / m ² or less, and by setting the treatment strength, the surface tension can be set in the above range.

When the adhesion start temperature is within the above range,
The press temperature during the processing of the capacitor can be lowered, and the withstand voltage of the capacitor can be improved without impairing the heat resistance and mechanical properties of the PPS film of the present invention.

Here, the thermal adhesion start temperature in the present invention will be described with reference to the drawings. FIG. 1 is a side view showing a sample film setting method in a thermal adhesion evaluation method according to the present invention, and FIG. 2 is a plan view thereof.

As shown in FIGS. 1 and 2, the width is 30 m.
m, length 10 mm, thickness 25 μm on a Toray Dupont Kapton film (a), width 20 mm, length 80 mm
The sample film (b) sampled in (2) was placed on top of another so that the contact area was 20 × 20 mm ^2, and then the Kapton film (a) was placed thereon. In this way, the Kapton film (a) and the two-layered sample film (b) were sequentially stacked so that (a + b) × n + a, and n was 5. Subsequently, an aluminum plate spacer (c) having a width of 10 mm, a length of 30 mm, and a thickness of 0.2 mm is placed on this, and the area where the overlapped portion of the two stacked sample films (b) and the aluminum plate is covered by 10 × 20 mm. ^It was placed to be ² . The sample thus prepared was heat-adhered at a set temperature and 17 kg / cm ² for 30 minutes. Both ends of a set of two samples which were thermally adhered by such a method were measured by using Tensilon at a width of 20 mm and a test length of 5 mm.
0mm, temperature 25 ℃, humidity 65R
Under H%, a pair of samples (films) were pulled at a pulling speed of 5 mm / min, and the maximum force during the pulling was measured. (Maximum force / contact during the pulling) The area) was taken as the adhesion (g / mm ² ), the adhesion temperature at which the adhesion was 1.3 g / mm ² was taken as the thermal adhesion start temperature, and the average value of the adhesion start temperatures of 5 samples was adopted.

In the polyphenylene sulfide film of the present invention, it is preferable that a metal film is formed on at least one surface of the film. However, the surface of the film on which the metal film is not formed has a surface tension of 40 dy.
n / cm or more, and the thermal adhesion start temperature is 150 ° C.
The following is preferred. The surface tension is more preferably 45 dyn / cm or more and 72 dyn / cm or less, even more preferably 60 dyn / cm or more, and 72 dyn / c.
m or less, and the thermal adhesion start temperature is more preferably 110 ° C. or more and 140 ° C. or less, more preferably 110 ° C. or less.
The temperature is not less than 130 ° C and not less than 130 ° C.

The polyphenylene sulfide film of the present invention is basically composed of a resin (PPS resin) containing polyphenylene sulfide as a main component.

The PPS resin in the present invention means that PPS is preferably 70% by weight or more, more preferably 85% by weight.
It refers to the resin composition containing the above, and as long as it is less than 30% by weight, preferably less than 15% by weight, it may contain an organic or inorganic additive, inert particles, an antistatic agent or the like. PPS refers to a polymer in which preferably at least 70 mol%, more preferably at least 85 mol% of the repeating units are composed of polyphenylene sulfide. If the content of such a component is less than 70 mol%, the crystallinity and softening point of the polymer may be reduced, and the heat resistance, dimensional stability, mechanical properties, and the like, which are characteristics of PPS, may be impaired. If the amount of the repeating unit is less than 30 mol%, preferably less than 15 mol%, a repeating unit copolymerizable with a phenylene sulfide unit, for example, an ether unit, a sulfone unit, a biphenyl unit, a naphthyl unit, a substituted phenyl sulfide unit, a trifunctional unit It can be composed of a phenyl sulfide unit or the like. Further, the bonding of the copolymer units may be either block or random. Further, the melt viscosity of the PPS resin of the present invention is 30 ° C.
0 ° C., under a shear rate of 200 sec ⁻¹ , preferably 100 to 50,000 poise, more preferably 500 to 50,000 poise.
It is preferably in the range of 12,000 poise from the viewpoint of film forming properties.

The PPS film of the present invention preferably contains inorganic particles and / or organic particles from the viewpoint of withstand voltage. The average particle size of the inorganic particles and / or the organic particles is not particularly limited, but is preferably from 0.1 to
It is 3.0 μm, more preferably 0.1 to 2.0 μm. Further, the content is not particularly limited, but is 0.005.
To 3% by weight, preferably 0.01 to 1.0% by weight.

Preferred examples of such particles include particles selected from calcium carbonate, alumina, hydroxyapatite, aggregated or monodispersed silica, titanium oxide, organic particles using polystyrene as a crosslinking agent, and carbon black. . A plurality of these particles may be used in combination. Although the relative standard deviation of the particle size distribution is not particularly limited, the pressure resistance is particularly improved when it is preferably 1.0 or less, more preferably 0.5 or less.

The polyphenylene sulfide copolymer can be copolymerized with a paraphenylene sulfide unit, for example, a metaphenylene sulfide unit,
It can be composed of ether units, sulfone units, biphenyl units, naphthyl units, substituted phenyl sulfide units, trifunctional phenyl sulfide units, and the like. Further, the bonding of the copolymer units may be either block or random.

The resin composition containing PPS refers to a resin composition containing 70% by weight or more, preferably 80% by weight or more of a polyphenylene sulfide polymer and / or a polyphenylene sulfide copolymer, and the remaining less than 30% by weight is a lubricant, Colorants, flame retardants, organic and / or inorganic particles, other resins and the like may be included.

In the present invention, a cross-linking agent may be contained as long as the properties of the film are not impaired. As the cross-linking agent, for example, methylolated or alkylolated urea-based, melamine-based, acrylamide-based, polyamide-based resins, and epoxy compounds,
Examples include isocyanate compounds.

The surface roughness (Ra) of the PPS film of the present invention is preferably in the range of 30 to 120 nm in view of suitability for metal deposition and capacitor processing. The above range is preferable for the roughness (Ra). If the surface roughness (Ra) exceeds the above-mentioned range, it is not preferable because the adhesiveness is deteriorated in the capacitor making process and the surface transfer occurs. On the other hand, if the surface roughness (Ra) is less than the above range, the handleability at the time of winding or the like deteriorates, which is not preferable.

The PPS film of the present invention has a temperature of 230 ° C.
The lower heat shrinkage ratio is 0 to 10 in the longitudinal direction (MD).
%, And a range of −2 to 5% in the direction perpendicular to the longitudinal direction (TD) is preferable in view of the moldability and the capacitor characteristics of the capacitor element, and the above range is preferable in the metallized film after the production of the capacitor.

Further, the thickness of the PPS film of the present invention is:
Although not particularly limited, it is preferably 3 μm or less, more preferably in the range of 0.5 to 2 μm, and still more preferably in the range of 0.7 to 2 μm from the viewpoint of effectively achieving the object of the present invention.

The capacitor of the present invention is a metallized film formed by forming a metal film on at least one side of the PPS film, and winding or laminating the metallized films alternately or a double-sided metallized film and a non-metallized film. It is produced by

The method for forming the metal film includes a vacuum deposition method and a sputtering method, but the vacuum deposition method is preferred from the viewpoint of economy. In addition, the metal to be deposited is not particularly limited, and includes the metals described below. Aluminum is preferably used from the viewpoint of vapor deposition workability and capacitor characteristics.

The capacitor of the present invention is not limited to the shape of the capacitor, the method of forming the extraction electrode, and the presence or absence of the exterior, and can be appropriately selected according to the purpose.

In order to enhance the adhesion between the metal-deposited layer and / or the metal-deposited PPS film, a surface treatment such as a corona treatment, a plasma treatment, a primer treatment or the like may be performed singly or in combination. Good.

Next, the PPS film of the present invention and a method for manufacturing a capacitor using the PPS film will be described. However, the PPS film of the present invention and its PP
The method for producing the S film is not limited to the method described here.

(1) Method for Producing PPS Film The PPS used in the present invention can be obtained by a method in which alkali sulfide and p- or m-dihalobenzene are reacted in a polar solvent at high temperature and high pressure. In particular, sodium sulfide and p- or m-dichlorobenzene are converted to N-methyl-
The reaction is preferably performed in an amide-based polar solvent such as 2-pyrrolidone (hereinafter sometimes referred to as NMP). In this case, in order to adjust the degree of polymerization, it is most preferable to add a so-called polymerization aid such as a caustic alkali or an alkali metal carboxylate and react at 230 to 280 ° C. The pressure and the polymerization time in the polymerization system are appropriately determined depending on the type and amount of the auxiliary agent used, the desired degree of polymerization, and the like.

In order to produce a PPS film from PPS, for example, a known method described in JP-B-63-122772 can be used. That is, the PPS composition obtained by adding an additive such as a lubricant to the PPS obtained as described above is dried under reduced pressure, supplied to a known extruder, melted out of a slit die, rapidly cooled, and cooled. Formed into a crystal sheet. Here, it is preferable to provide a filtration device between the extruder and the die for the purpose of removing coarse foreign substances such as dust or additives from the viewpoint of obtaining a film having no defects. PP
An ordinary method can be used for forming the S film.
The polymer is discharged from the die, closely adhered to a drum having a surface temperature of 25 ° C. by an electrostatic application method, and rapidly cooled to form an amorphous sheet. Next, the amorphous sheet is subjected to a well-known sequential biaxial stretching method, simultaneous biaxial stretching method, or the like at a temperature of 85 to 130 ° C. at a magnification of 1.5 to 4.5 times for each of both axes. The film is stretched to obtain a biaxially stretched film. Subsequently, the obtained biaxially stretched film is subjected to a constant-length heat treatment in a tenter at a temperature in the range of 200 ° C. or higher and the melting point or lower for 1 to 60 seconds, and if necessary, limited shrinkage in a temperature range of 200 ° C. or lower and the melting point or higher. Then, a PPS film is obtained.

Here, in the present invention, the surface tension of the PPS film on the side where the metal film is not formed is 4%.
0 dyn / cm or more, and the thermal adhesion start temperature is 1
In order to reduce the temperature to 50 ° C. or lower, it is preferable to perform a corona discharge treatment, a plasma treatment, or a primer treatment on both surfaces of the film or the film surface on which the metal film is not formed, and more preferably to perform a corona discharge treatment. Is particularly useful for achieving the object of the present invention. Here, as the corona discharge treatment method, EC treatment, N
E treatment and CE treatment are preferred. Further, by setting the treatment strength in the corona discharge treatment to 20 W · min / m ² or more, the film of the present invention can be easily obtained.

(2) Method for Producing a Capacitor The capacitor of the present invention is a capacitor using the above PPS film as a dielectric. After forming a metal film to be an electrode on at least one surface of the above PPS film to form a metallized film. The dielectric and the electrode are alternately overlapped by alternately overlapping and winding by a winding method, a laminating method, or the like, and are manufactured to have a structure in which the electrode can be drawn out to the outside.

The method of forming the metal film includes a vacuum deposition method and a sputtering method, but the vacuum deposition method is preferable from the viewpoint of economy. In the vacuum deposition method, P
A metal is deposited on the PS film from an evaporation source to form a metal on the PPS film. Examples of the evaporation source include a boat type of a resistance heating type, a crucible type by radiation or high-frequency heating, and a type by electron beam heating, but are not particularly limited.

The metal used for this deposition is Al, Z
Metals such as n, Mg and Sn are preferred, but Ti, In,
Cr, Ni, Cu, Pb, Fe and the like can also be used. These metals have a purity of at least 99%, preferably at least 99.5%, in the form of granules, rods, tablets,
It is preferably processed into a wire shape or a crucible shape.

In this vacuum deposition, aluminum is particularly preferred in terms of productivity and cost. Aluminum is deposited on at least one side to provide an aluminum metal layer.
For example, other metal components such as nickel, copper, gold, silver, chromium, zinc, etc. can also be deposited. Also, aluminum vapor deposition is particularly preferable in terms of vapor deposition processability and capacitor characteristics. At the time of metallization, the adhesion between the metal thin film and the film can be improved by corona discharge treatment, plasma treatment or the like on the surface of the film to be metallized in advance. Also,
Non-metallized portion (so-called margin) by tape mask, oil margin, laser beam, etc. so that the counter electrode does not short-circuit during or after metallization
It is a usual method to provide, discharge after depositing the entire surface,
The non-metallized zone can be provided using a laser beam or the like. Thereafter, slitting may be performed in a narrow tape shape so that a margin portion comes to one end.

Next, a method for manufacturing a capacitor element will be described. To obtain a wound capacitor, slit the metallized film into a narrow tape so that the margin is at one end, and then stack two sheets so that the margin is on the opposite side, or use double-sided metal. It is a common method to stack a functionalized film and a non-metallized film and individually wind individual elements.

In general, the capacitor element thus obtained is press-molded, and can be heated to a temperature of 100 ° C. or higher and lower than the melting point of the film. After that, obtain the capacitor through external electrode mounting process (using metal spraying, conductive resin, etc.), resin or oil impregnating process if necessary, and lead wire mounting process and exterior process when using lead type capacitors. Can be.

In the case of a multilayer capacitor, it is wound on a large-diameter drum or a flat plate in the same manner as the winding type.
In this state, the mother element is obtained by applying heat in the thickness direction of the film, such as heat treatment, clamping with a ring or the like, or pressing with a parallel plate or the like. The temperature range at that time is generally from room temperature to the melting point of PPS or lower. Thereafter, a capacitor can be obtained through a process of attaching external electrodes to the above-mentioned mother element by metal spraying, a conductive resin or the like, a step of cutting out individual elements, and if necessary, a step of impregnating resin or oil.

Next, a method for evaluating characteristics used in the present invention will be described.

[Evaluation Method of Characteristics] (1) Surface tension Measured according to JIS K-6768.

(2) Heat shrinkage rate Measured at 230 ° C. in accordance with JIS C-2151.

(3) Surface roughness Ra Cut-off 0.08 m in accordance with JIS R-0601
m.

(4) Thermal Adhesion Force, Thermal Adhesion Starting Temperature Measured according to the description of FIGS. 1 and 2 described above.

(5) Characteristics of Capacitor Poor withstand voltage Using a DC withstand voltage tester (manufactured by Kasuga Electric), 100 V to the film thickness at a voltage rise rate of 100 V / sec.
When the current flowed at 10 mA or more at a voltage of not more than / μm and the voltage rise stopped, it was regarded as defective. 100 capacitors were measured and expressed as a percentage (%) of the defective number.

[0049]

Next, the present invention will be described in detail with reference to examples.

Example 1 As a crystalline PPS polymer, a powder of poly-p-phenylene sulfide was used.
This crystalline PPS polymer powder has an average particle size of 0.5 μm
Was blended in an amount of 0.5% by weight to obtain PPS pellets using a vented twin-screw extruder.

The PPS pellets are dried in a rotary vacuum dryer.
At 150 ° C. under a reduced pressure of 3 mmHg for 3 hours.
Next, the PPS pellets were melted at a melting temperature of 330 ° C. for 1 hour.
Pass through a 0 μm filter, lip width 400m
m, stainless steel T die with slit gap 1.0mm
And cooled on a metal drum whose surface is kept at 25 ° C
It was solidified to form an amorphous sheet having a thickness of 20 μm. Then
This amorphous sheet is wound around a rotating roll group having a surface temperature of 95 ° C.
And then heated and subsequently placed at a surface temperature of 97 ° C.
3.5 times the length of the film between rolls with different peripheral speeds
Stretched in the direction (MD). Next, at 100 ° C with a tenter
In a room in which hot air circulates, the direction perpendicular to the longitudinal direction of the film (T
D) is stretched 3.5 times, followed by circulation of hot air at 270 ° C.
Fixed length heat treatment for 10 seconds in a ringing room, then 5% in width direction
With a thickness of 1.2 μm biaxially oriented PP
S film was obtained. The biaxial orientation P thus obtained
On the film surface of the PS film where the metal is not deposited,
Processing strength is 60W min / m ^TwoCorona release to become
Electric treatment (EC treatment) was performed. This corona discharge treatment
The surface tension of the film on the dried side is 68 dyn / cm, and
The thermal adhesion start temperature was 125 ° C. The heat shrinkage is
4.5% at 230 ° C. for 10 minutes, surface roughness Ra is 23 nm
there were.

Next, using this laminated film, a wound capacitor was prepared and evaluated under the following conditions. The defective ratio of withstand voltage of this capacitor was 3%. [Conditions for making capacitor element] Internal electrode: Aluminum deposition, 2Ω / □ Film width: 13 mm Margin width: 1 mm Press temperature: 150 ° C. Press pressure: 25 kg / cm ² Press time: 5 minutes Capacitance: 0.35 μF Extraction electrode: Metallicon (metal spraying) (Example 2) A biaxially oriented PPS film having a thickness of 1.2 μm was obtained in the same manner as in Example 1, and this biaxially oriented PPS film was obtained.
The procedure was performed in the same manner as in Example 1 except that a corona discharge treatment (EC treatment) was performed on the film surface on the side where the metal was not deposited on the film so as to have a treatment strength of 40 W · min / m ² . The surface tension of the film subjected to the corona discharge treatment is 65 dyn / cm, and the thermal adhesion start temperature is 1
29 ° C. The heat shrinkage was 4.5% at 230 ° C. for 10 minutes, and the surface roughness Ra was 23 nm. Using this laminated film, a wound capacitor was produced and evaluated in the same manner as in Example 1. This capacitor had a withstand voltage failure rate of 4%.

Example 3 In the same manner as in Example 2, a biaxially oriented PPS film having a thickness of 1.2 μm was obtained, and a processing strength of 40 W was applied to the film surface of the biaxially oriented PPS film on the side where no metal was deposited. -It carried out similarly to Example 1 except having performed corona discharge treatment (NE treatment) so that it might become min / m < ² >. The surface of the film on which the corona discharge treatment was performed had a surface tension of 65 dyn / cm and a thermal adhesion start temperature of 129 ° C. The heat shrinkage is 230 ° C
4.5% in 10 minutes, and the surface roughness Ra was 23 nm.
Using this laminated film, a wound capacitor was produced and evaluated in the same manner as in Example 1. This capacitor had a withstand voltage failure rate of 4%.

Example 4 A biaxially oriented PPS film having a thickness of 1.2 μm was obtained in the same manner as in Example 1, and a processing strength of 20 W was applied to the film surface of the biaxially oriented PPS film on which the metal was not deposited. -Except having performed corona discharge processing (EC processing) so that it might become min / m < ² >, it implemented similarly to Example 1. The surface tension on the side subjected to this corona discharge treatment is 58 dyn / cm, and the thermal adhesion start temperature is 1
38 ° C. The heat shrinkage was 4.5% at 230 ° C. for 10 minutes, and the surface roughness Ra was 23 nm. Using this laminated film, a wound capacitor was produced and evaluated in the same manner as in Example 1. This capacitor had a withstand voltage failure rate of 6%.

Example 5 In the same manner as in Example 4, a biaxially oriented PPS film having a thickness of 1.2 μm was obtained, and a processing strength of 20 W was applied to the film surface of the biaxially oriented PPS film on which the metal was not deposited.・ Corona discharge treatment so as to be min / m ² (CE treatment: nitrogen: carbon dioxide = 7: 3)
Was performed in the same manner as in Example 1 except that The surface tension of the film subjected to the corona discharge treatment is 65.
dyn / cm, and the thermal adhesion start temperature was 137 ° C. The heat shrinkage was 4.5% at 230 ° C. for 10 minutes, and the surface roughness Ra was 23 nm. Using this laminated film, a wound capacitor was produced and evaluated in the same manner as in Example 1. This capacitor had a withstand voltage failure rate of 7%. (Embodiment 6) In the same manner as in Embodiment 1, the thickness 1.2
After obtaining a biaxially oriented PPS film having a thickness of 20 μm, a processing strength of 20 W · min / m
^A corona discharge treatment (EC treatment) is performed to obtain a biaxially oriented PPS film without metal deposition, and a film with metal deposition on both sides of the biaxially oriented PPS film. A biaxially oriented PPS film and a metal-deposited film were laminated, and a wound capacitor was prepared and evaluated in the same manner as in Example 1 under conditions for preparing a capacitor element. The surface tension of the PPS film subjected to the corona discharge treatment was 68 dyn / cm, and the thermal adhesion start temperature was 125 ° C. The heat shrinkage is 230 ° C. 10
And the surface roughness Ra was 23 nm. The defective ratio of withstand voltage of this capacitor was 3%.

Comparative Example 1 For comparison, the P of Example 1 was used.
A PPS film and a capacitor were produced in the same manner as in Example 1 except that no treatment was performed on the surface of the PS film (no corona discharge treatment (EC treatment) was performed). The heat bonding temperature of this PPS film was 154 ° C. The withstand voltage failure rate of the produced capacitor is 30%.
%Met.

(Comparative Example 2) For comparison, a thickness of 1.2 μm was used.
m, a biaxially oriented PPS film is obtained.
The procedure was performed in the same manner as in Example 1 except that the corona discharge treatment (EC treatment) was performed so that the treatment strength was 5 W · min / m ² on the film surface of the PS film on which the metal was not deposited. The surface of the film subjected to the corona discharge treatment has a surface tension of 43 dyn / cm and a thermal adhesion start temperature of 153.
° C. The heat shrinkage was 4.5% at 230 ° C. for 10 minutes, and the surface roughness Ra was 23 nm.

Table 1 shows the results of the above Examples and Comparative Examples.

[0059]

[Table 1]

[0060]

According to the present invention, since the withstand voltage is improved while maintaining the heat resistance, frequency characteristics and mechanical characteristics of the PPS film, the yield of capacitor production is improved, and a highly reliable capacitor is obtained. A PPS film suitable for is obtained. Especially, the surface tension of the film is 40 dy.
n / cm or more, and the thermal adhesion start temperature is 150 ° C.
Because of the following, a capacitor having excellent withstand voltage can be obtained.

[Brief description of the drawings]

FIG. 1 shows a method for evaluating thermal adhesion according to the present invention.
It is a side view which shows the sample setting method of a sample film.

FIG. 2 illustrates a method for evaluating thermal adhesion according to the present invention.
It is a top view which shows the sample setting method of a sample film.

[Explanation of symbols]

 a: Toray Dupont Kapton film b: Sample film in which two sheets overlapped c: Aluminum plate (spacer)

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01G 4/18 C08L 81:02 // C08L 81:02 H01G 4/24 321C F-term (Reference) 4F006 AA40 AB73 BA07 DA01 4F071 AA62 AF06Y AF58Y AH12 BA01 BB06 BB08 BC01 BC12 4F073 AA01 BA32 BB01 CA01 CA21 EA00 5E082 AB03 AB04 BC38 EE07 EE11 EE23 EE37 FF05 FG06 FG34 FG39 FG48 FG56 PP06 PP09 PP10 PP10

Claims (6)

[Claims] 1. The film has a surface tension of 40 dyn / cm.
A polyphenylene sulfide film, wherein the thermal adhesion start temperature is 150 ° C. or lower. 2. The polyphenylene sulfide film according to claim 1, wherein the surface of the film on which the metal film is not formed has a surface tension of 40 dyn / cm or more and a thermal adhesion start temperature of 150 ° C. or less. . 3. The polyphenylene sulfide film according to claim 1, wherein a corona discharge treatment, a plasma discharge treatment, or a primer treatment is performed on a surface of the film on which the metal film is not formed. 4. The polyphenylene sulfide film according to claim 1, wherein the film thickness is 3 μm or less. 5. A capacitor obtained by winding or laminating a metallized polyphenylene sulfide film obtained by forming a metal film on at least one surface of the polyphenylene sulfide film according to claim 1. 6. A capacitor obtained by winding or laminating a polyphenylene sulfide film according to claim 1 and a metalized polyphenylene sulfide film obtained by forming a metal film on both surfaces of the polyphenylene sulfide film.