JP2009035575A - Polyphenylene sulfide film roll for capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a film roll that can improve a capacitor processing yield with high lamination accuracy by suppressing meandering during film travel in manufacturing a laminated film capacitor. <P>SOLUTION: This polyphenylene sulfide film roll for the capacitor is formed of a polyphenylene sulfide film with a film thickness of 10 μm or less, with a specially defined air entangling index X[%] expressed by expressions 1, 2, wherein the expression 1 is (-2.5×10<SP>-4</SP>×L)+22<X<(-2.5×10<SP>-4</SP>×L)+32, the expression 2 is (-3.44×10<SP>-2</SP>×D)+26<X<(-3.44×10<SP>-2</SP>×D)+36, L is a film length [m], and D is a film roll diameter [mm]. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a polyphenylene sulfide film roll for capacitors, and provides a film roll having excellent processing characteristics by suppressing meandering during film conveyance.

  A polyphenylene sulfide film is suitably used as a dielectric for a film capacitor, and it has been conventionally known to incorporate inert particles in order to improve its properties. For example, a polyphenylene sulfide film is disclosed in which two types of particles having a defined particle shape are used to achieve both slipperiness, runnability, and low insulation defects (Patent Documents 1 and 2). Further, a polyphenylene sulfide film in which coarse particles are suppressed and voids are reduced using calcium carbonate fine particles is known (Patent Document 3).

However, in such a method, when the multilayer capacitor which has become mainstream these days is manufactured due to insufficient release of air existing between the layers of the film roll, There were drawbacks such as a worse processing yield.
JP-A-5-163370 JP-A-6-136146 JP 2004-149740 A

  An object of the present invention is to provide a film roll that has good lamination accuracy and can improve the capacitor processing yield by suppressing meandering during film travel when producing a laminated film capacitor.

In order to solve the above problems, the polyphenylene sulfide film roll for capacitors of the present invention has the following constitution. That is, it is a roll made of a polyphenylene sulfide film having a film thickness of 10 μm or less, and an air pocket index X [%] defined in the specification is a polyphenylene sulfide film roll for a capacitor represented by Formulas 1 and 2.
(Formula 1) (−2.5 × 10 ⁻⁴ × L) +22 <X <(− 2.5 × 10 ⁻⁴ × L) +32
(Formula 2) (−3.44 × 10 ⁻² × D) +26 <X <(− 3.44 × 10 ⁻² × D) +36
L: Film length [m]
D: Film roll diameter [mm]

  By using the film roll provided in the present invention, meandering during film travel when producing a laminated film capacitor is suppressed, the lamination accuracy is good, and the capacitor processing yield can be improved.

The best embodiment of the present invention will be described below.
In the present invention, polyphenylene sulfide refers to a polymer in which 80 mol% or more (preferably 90 mol% or more) of repeating units are composed of structural units represented by the following chemical formula.

If the component is less than 80 mol%, the crystallinity and softening point of the polymer are lowered, and the heat resistance, dimensional stability and mechanical properties of the resulting film are impaired. As long as it is less than 20 mol% (preferably less than 10 mol%) of the repeating unit, a unit containing a copolymerizable sulfide bond may be contained. The copolymerization method of the polymer may be random or block.

In the present invention, the polyphenylene sulfide resin composition refers to a resin composition containing 90% by weight or more of the polyphenylene sulfide (preferably poly-p-phenylene sulfide). The remaining less than 10% by weight in the resin composition may be a polymer other than polyphenylene sulfide and / or an additive such as a filler, a colorant, an ultraviolet absorber, an antistatic agent, and an antioxidant. The melt viscosity of the polyphenylene sulfide resin composition of the present invention is preferably in the range of 100 to 50000 poises, more preferably 500 to 12000 poises at a temperature of 300 ° C. and a shear rate of 200 sec ⁻¹ in terms of film forming properties.

  The polyphenylene sulfide film of the present invention is a biaxially stretched film obtained by melt-molding the polyphenylene sulfide resin composition. In order to obtain electrical characteristics sufficient for capacitor use, a biaxially stretched film is preferable instead of an unstretched film or a uniaxially stretched film. The thickness of the film is preferably 10 μm or less, and more preferably in the range of 0.5 to 6.0 μm from the viewpoint of effectively achieving the object of the present invention. Further, for the purpose of providing an easy-adhesion effect, a single or composite surface treatment may be applied to the corona treatment, the plasma treatment, and the primer treatment.

  In the present invention, a capacitor is a kind of electric circuit, and means a capacitor that provides a certain amount of static electricity between two electrodes by providing a pair of electrodes made of a conductor with a dielectric sandwiched between them. Is.

  It is desirable to use inert particles in the polyphenylene sulfide film of the present invention. The inert particles used in the present invention do not melt up to 300 ° C. like inorganic particles such as silica, alumina, calcium carbonate, kaolin, calcium phosphate, barium sulfate, titanium oxide, talc, zinc oxide and crosslinked polystyrene particles. Organic particles are mentioned. Preferred are silica particles resulting from colloidal silica, spherical calcium carbonate, and crosslinked polystyrene-based particles. Since these particles have a good affinity with the polymer and do not easily generate voids around the particles during stretching, the film has a good withstand voltage as a capacitor film.

  In the present invention, it is preferable to use the above types of particles and two types of inert particles having different particle sizes. The combination of the particle types is not particularly limited, but the particle shape is preferably a spherical or flat particle in order to drop the particle and reduce voids.

  The average particle size of the first inert particles (hereinafter sometimes referred to as inert particles A) used in the present invention is in the range of 0.3 to 0.8 μm, more preferably 0.4 to 0.00. The range is 6 μm. If the average particle size is less than 0.3 μm, the slipperiness of the film is not sufficient, which causes film breakage when metal is deposited on the film. On the other hand, when the thickness exceeds 0.8 μm, the interlayer adhesion cannot be obtained and the film is turned over when processed into a capacitor. The second inactive particles (hereinafter sometimes referred to as inactive particles B) are composed of particles having an average particle size larger than that of the inactive particles A, and the average particle size is in the range of 1.0 to 1.5 μm. Is more preferable, and the range of 1.0 to 1.2 μm is more preferable. When the inert particle B is less than 1.0 μm, sufficient slipperiness cannot be obtained when forming a film roll, and wrinkles and charging defects are generated. On the other hand, when the thickness exceeds 1.2 μm, voids formed adjacent to the particles become large, so that the dropout of particles and the increase of insulation defects are likely to occur.

  In the present invention, the inert fine particles A are added in an amount of 0.4 to 0.8% by weight, preferably 0.5 to 0.7% by weight. If the addition amount of the inert fine particles A is less than 0.4% by weight, the slipperiness of the film is not sufficient, and if it exceeds 0.8% by weight, the voids formed around the fine particles and the electrical resistance of the inert fine particles themselves are increased. Is low, the dielectric strength of the film is reduced. The addition amount of the inert fine particles B is 0.05 to 0.3% by weight, preferably 0.1 to 0.2% by weight. If the added amount of the inert fine particles B is less than 0.05% by weight, good slipperiness cannot be obtained, and if it exceeds 0.3% by weight, there is a risk of increasing voids.

  In the present invention, it is necessary to use particles satisfying the above range, but it is necessary to use spherical silica for both the inert particles A and B. This is particularly desirable from the viewpoint of meandering suppression.

  The film roll in the present invention preferably has a width of 300 to 1400 mm and a length of 4000 to 40000 m from the viewpoint of capacitor productivity. The roll surface layer hardness is 85 to 95 degrees, preferably 88 to 92 degrees. If it is less than 85 degrees, winding deviation at the time of vacuum deposition is likely to occur, and if it exceeds 95 degrees, blocking occurs, causing film breakage.

The polyphenylene sulfide film roll for a capacitor of the present invention is a roll made of a polyphenylene sulfide film having a film thickness of 10 μm or less, and the air pocket index X [%] is represented by the formulas 1 and 2 as follows. It is.
(Formula 1) (−2.5 × 10 ⁻⁴ × L) +22 <X <(− 2.5 × 10 ⁻⁴ × L) +32
(Formula 2) (−3.44 × 10 ⁻² × D) +26 <X <(− 3.44 × 10 ⁻² × D) +36
L: Film length [m]
D: Film roll diameter [mm]
Both formulas 1 and 2 are experimentally obtained relational expressions, but when the polyphenylene sulfide film roll for capacitors of the present invention satisfies both formulas 1 and 2, the air release between the film layers is improved, It has been found that meandering during film travel during production of a laminated film capacitor is suppressed, the lamination accuracy is good, and the capacitor processing yield is improved. The air bit index X needs to be expressed by (−2.5 × 10 ⁻⁴ × L) +22 <X <(− 2.5 × 10 ⁻⁴ × L) +32 with the film length L. However, (−2.5 × 10 ⁻⁴ × L) +22 <X <(− 2.5 × 10 ⁻⁴ × L) +26 is preferable. Here, when X ≦ (−2.5 × 10 ⁻⁴ × L) +22, air is not easily released between the film layers, so air is caught between the film and the film or the film and the roll. Causes running meandering and laminating when the films are laminated, and the processing yield of the capacitor is significantly reduced. Further, if X ≧ (−2.5 × 10 ⁻⁴ × L) +32, the amount of air trapped between the film rolls becomes too large, and film displacement may occur at the time of vacuum evacuation when performing vapor deposition on the film. It tends to happen.

Further, the distance between the air bit index X and the film roll diameter D needs to be (−3.44 × 10 ⁻² × D) +26 <X <(− 3.44 × 10 ⁻² × D) +36. . Preferably, (−3.44 × 10 ⁻² × D) +26 <X <(− 3.44 × 10 ⁻² × D) +30. When X ≦ (−3.44 × 10 ⁻² × D) +26, as in the case of Equation 1, the film causes a meandering during the production of the capacitor, the lamination accuracy as a multilayer capacitor deteriorates, and the capacitor is processed. The yield is significantly reduced. Moreover, also when X ≧ (−3.44 × 10 ⁻² × D) +36, it is easy to cause a film shift at the time of vacuum deposition.
The surface roughness parameter SRa of the film surface of the present invention is 30 to 80 nm, preferably 40 to 60 nm. If SRa is less than 30 nm, the slipperiness of the film is not sufficient, and this causes film breakage when metal is deposited on the film. If SRa exceeds 80 nm, the interlayer adhesion cannot be obtained and the film is turned over when processed into a capacitor.

  Furthermore, the surface roughness parameter SRmax on the film surface of the present invention is 1000 to 1300 nm, preferably 1000 to 1200 nm. When SRmax is less than 1000 nm, sufficient slipperiness cannot be obtained when forming a film roll, and wrinkles and charging defects occur. On the other hand, if it exceeds 1300 nm, the withstand voltage is lowered due to a wrinkle defect during processing of the capacitor, which is not preferable.

  Next, an example of a preferable method for producing a capacitor using the polyphenylene sulfide film roll for capacitors of the present invention and the film roll will be described. However, the production method of the present invention is not limited to this method.

First, a method for producing a polyphenylene sulfide film will be described.
As a polymerization method of polyphenylene sulfide, a method of reacting alkali sulfide and p-dihalobenzene at a high temperature in a polar solvent is used. In particular, sodium sulfide and dichlorobenzene (preferably p-dichlorobenzene) are preferably reacted in an amide polar solvent such as N-methyl-2-pyrrolidone. In this case, in order to adjust the degree of polymerization, it is most preferable to add a so-called polymerization aid such as caustic alkali or alkali metal carboxylate and react at 230 to 280 ° C. The pressure in the polymerization system and the polymerization time are appropriately determined depending on the type and amount of the auxiliary agent used and the desired degree of polymerization. The polymer after the polymerization is washed at a high temperature with a solvent having affinity for polyphenylene sulfide, such as N-methylpyrrolidone, and then washed with water and dried to obtain a polyphenylene sulfide powder. The inert particles can be added at any stage by any addition method. However, the inert particles dispersed in the liquid are mixed with the polyphenylene sulfide powder, and a high-speed stirring means such as a Henschel mixer is used. After the mixture is uniformly mixed, the obtained mixture is supplied to an extruder having at least one stage of vent holes, and after melt-kneading in the extruder, the liquid component is removed from the vent holes, and an appropriate base is obtained. A method of obtaining a polyphenylene sulfide composition in which inert particles are finely dispersed by extrusion from the viewpoint of preventing generation and mixing of coarse particles is preferable. The liquid used for slurrying the inert particles preferably has a boiling point of 180 to 290 ° C, particularly preferably 180 to 250 ° C. Specifically, ethylene glycol and N-methyl-2-pyrrolidone are preferable.

  The polyphenylene sulfide composition containing the inert particles thus obtained can be biaxially stretched as it is or mixed with plain pellets containing no particles. The polyphenylene sulfide composition pellets in which inert particles are dispersed are mixed as they are or plain pellets made of a polyphenylene sulfide composition not containing inert particles are mixed, supplied to an extruder, melted, and discharged from a die.

  The molten resin discharged from the die is cooled and solidified using electrostatic application on a cooling drum having a surface temperature of 20 to 30 ° C. and a diameter of 800 to 2000 mm, but is necessary in the polyphenylene sulfide film roll for capacitors according to the present invention. In a thin film having a film thickness of 10 μm or less, it is necessary to use a method for forming a high-speed film by forming a water film on a cooling drum and increasing the adhesion. In the polyphenylene sulfide film roll for capacitors of the present invention, it is necessary to reduce the film thickness unevenness as much as possible, and as a result of examining the water film thickness on the cooling drum required for that purpose, the water film thickness is 0. It has been found that the thickness is preferably 5 to 2.0 μm or less, preferably 0.8 to 1.5 μm.

Next, the unstretched film is stretched in the longitudinal direction and in the direction orthogonal to the longitudinal direction. In order to achieve the air bit index and film surface roughness of the present invention, the stretching conditions in the longitudinal direction are very important, and the effects of the present invention can be achieved only under the optimal stretching conditions. The stretching condition in the longitudinal direction is the number of free rolls wound around a plurality of free roll groups having a surface temperature of 90 ° C. or more and less than 120 ° C. between driving rolls, and the stretching section is 50 mm to 500 mm, preferably 200 mm to 300 mm. And is stretched 3 to 5 times in the longitudinal direction to obtain a uniaxially stretched film.
Next, a biaxially stretched film is stretched 2 to 4 times in the longitudinal direction in a 90 to 130 ° C. tenter, followed by a constant length heat treatment for 2 to 60 seconds in a temperature range of 200 ° C. or higher and a melting point or lower in the tenter, If necessary, the polyphenylene sulfide film is wound up after being subjected to limited shrinkage in a temperature range of 200 ° C. or higher and a melting point or lower.

  The wound polyphenylene sulfide film is slit to a predetermined width and length and wound around a cylindrical core. At this time, in the polyphenylene sulfide film roll for a capacitor of the present invention, the slit condition is extremely important for controlling the air bit index. The slit conditions of the wound polyphenylene sulfide film loom are as follows: the tension during winding is 0.5 to 10.0 kg / m, the surface pressure during winding is 5 to 60 kg / m, and the slit speed is 50 to 250 m / min. Preferably there is. Further, a contact roll method is desirable as the surface pressure applying method, and it is preferable to use a metal plating roll as the contact roll in order to achieve the air contact index of the present invention.

Next, an example of a preferable method for manufacturing the capacitor of the present invention will be described.
As the internal electrode of the capacitor, when a metal foil is used, the dielectric of the metal foil and the film of the present invention is alternately overlapped and wound by a method such as winding a foil or inserting a tab in the middle of winding. A capacitor element or a capacitor mother element is obtained by alternately stacking a body and an electrode and winding the electrode so that the electrode can be drawn to the outside.

  When a metal thin film is used as the internal electrode of the capacitor, the above-described film of the present invention is first metallized. The metallization method is preferably a vapor deposition method. The metal to be deposited is preferably a metal mainly composed of aluminum. When metallizing, the film surface on the side to be metallized in advance can be subjected to treatment such as corona discharge treatment or plasma treatment to improve the adhesion between the metal thin film and the film. A non-metal portion (so-called margin) may be provided by a tape mask, an oil margin, a laser beam, or the like so that the counter electrode is not short-circuited during or after metallization. After that, the tape may be slit into a narrow tape shape so that a margin part comes to one end.

  Next, a capacitor element is manufactured. In the case of a multilayer capacitor, the mother element wound around a drum or a flat plate is heat-treated, fastened with a ring or the like, or pressed with a parallel flat plate or the like, and is formed by applying pressure in the thickness direction of the film. The temperature range in that case is from normal temperature to below the melting point of the film. Thereafter, the capacitor can be obtained through an external electrode attaching step (by metal spraying, conductive resin, etc.), individual element cutting steps, and if necessary, a resin or oil impregnation step.

[Measurement method of physical properties]
1. Film thickness First, the weight of the film product roll is measured. Next, the film width is measured with the calibrated tape measure, and the length is measured by unwinding the film. Further, the core weight is measured. The film weight is obtained by subtracting the core weight from the film product roll weight. The density was measured by sampling the film from the roll surface layer and using a density gradient tube at 25 ° C. of an aqueous inorganic salt solution composed of lithium bromide / water. The film thickness is obtained from the following formula.
T = film weight / (film width × film length × density)
T: Film thickness [μm].

2. The outer peripheral length of the air bit index polyphenylene sulfide film roll is measured using a tape measure at the center position in the roll width direction, and the diameter is determined from the outer periphery. The film thickness and film length are measured by the above method 1. The air bit index is expressed by the following formula.
X = (100π (D ² −D ₀ ² ) / 4TL) −100
X: Air contact index [%]
D: Film roll diameter [mm]
D ₀ : Core diameter [mm]
T: Film thickness [μm]
L: Film length [m].

3. Film surface roughness (central surface average roughness SRa, maximum height SRmax)
It sampled from the surface layer of the polyphenylene sulfide film roll, measured 3 times on the following conditions using the stylus type fine shape measuring machine ET-4000AK made from a Kosaka laboratory, and calculated | required the average value.
Measurement direction: Film longitudinal direction and perpendicular direction Feed direction: Film longitudinal direction stylus tip diameter: 2 [μm]
Stylus load: 20 [μN]
Measurement length: 0.5 [mm]
Measurement pitch: 1 [μm]
Feed pitch: 5 [μm]
Number of measurement: 100 [pieces]
Low frequency cut-off value: 0.25 [mm]
When the roughness curved surface f (x, y) is obtained under the above conditions, SRa is expressed by the following equation.

lx: Measurement length [mm]
ly: Feed pitch [μm] x number of measurement [lines]
S: lx x ly
The maximum peak and the deepest valley of the measurement range are sandwiched between two planes parallel to the average plane, and the interval is defined as the maximum height SRmax.

4). The average particle diameter of the inert particles Sampled from the surface layer of the polyphenylene sulfide film roll, and fixed to the sample stage of the scanning electron microscope, the surface of the measurement film was measured using a sputtering apparatus with a degree of vacuum of 10 ⁻³ Torr, a voltage of 0.25 KV, and an electric current. Ion etching treatment is performed for 10 minutes under the condition of 12.5 mA. Next, the surface is sputtered with gold using the same apparatus, and photographs of 10,000 to 30,000 times are taken with a scanning electron microscope. The average particle diameter d is determined from the above formula by obtaining the area circle equivalent diameter di of 100 or more particles and n particles. Here, the area circle equivalent diameter di is the diameter of each circumscribed circle.

d: Average particle diameter [μm]
di: equivalent area circle diameter [μm]
n: Number of measured particles [pieces]
5). The amount of inert particles added Sampled from the surface layer of the polyphenylene sulfide film roll, the measurement film was dissolved in α-chloronaphthalene, filtered while hot to separate the particles, and expressed as a ratio (% by weight) to the total film weight. Moreover, it can also quantify using infrared spectroscopy, a fluorescent X ray method, and SEM-XMA as needed.

6). Water Film Thickness The water film thickness was measured using an ink thickness / water content meter “RX-220” manufactured by Kurashiki Boseki Co., Ltd.

7). Aluminum was vapor-deposited on one side of a polyphenylene sulfide film roll running at the time of capacitor production so as to have a surface resistance of 2Ω / □ using a continuous vacuum vapor deposition apparatus (evaporation width 8 mm, margin width 1.0 mm). This vapor deposition film was slit so that the vapor deposition width was 4 mm and the margin width was 0.5 mm, and two sets of reel samples were stacked so that the margin portion was on the outside, and wound 30 m around a drum having a diameter of 300 mm, and this was laminated 20 times. . A scale is attached in the middle of the winding device, and the maximum deflection to the left and right during film running during the stacking of the reel sample 30m 20 times is defined as the meandering amount. If it is 0.5 to 1.0 mm, it is judged as “good”, and if it is 1.0 mm or more, it is judged as “bad”.

8). After the capacitor processing yield was stacked, a metal band was fitted and fixed at a pressure of 100 Pa, and then heat-treated in an oven at 200 ° C. for 1 hour. Thereafter, metallicon was sprayed on both end faces of the reel, and each layer was removed. It was cut into a size of 5 mm in length, and a lead wire was attached to the metallicon part to produce a capacitor. The shape of the obtained capacitor was confirmed by visual inspection, and those with wrinkles and deviations were rejected, and the ratio of the number of rejected products to the total number of production was expressed as a percentage as a workability index (hereinafter, Processing yield). The higher the processing yield, the better. The processing yield of 95% or more is excellent. If the processing yield is 85 to 95%, the result is good.

In order to make the present invention easier to understand, examples and comparative examples are shown below.

Example 1
(1) Preparation of polyphenylene sulfide A 50 L autoclave (manufactured by SUS316) was mixed with sodium hydrosulfide (NaSH) 56.25 mol, sodium hydroxide 54.8 mol, sodium acetate 16 mol, and N-methyl-2-pyrrolidone (NMP) 170. Charge the mole. Next, dehydration was performed by raising the internal temperature to 220 ° C. while stirring under a nitrogen gas stream. After dehydration, the system was cooled to 170 ° C., and 55 mol of p-dichlorobenzene (p-DCB) and 0.055 mol of 1,2,4-trichlorobenzene (TCB) were added together with 2.5 L of NMP. Then, the system was pressurized and sealed to 2.0 kg / cm ² under a nitrogen stream. After heating at 235 ° C. for 1 hour and further at 270 ° C. for 2 to 5 hours with stirring, the system was cooled to room temperature, and the resulting polymer slurry was poured into 200 mol of water and stirred at 70 ° C. for 30 minutes. Thereafter, the polymer is separated. The polymer was further washed five times with stirring at about 70 ° C. ion-exchanged water (9 times the polymer weight), and then stirred for about 1 hour under a nitrogen stream with a 5% by weight aqueous solution of lithium acetate at about 70 ° C. . Further, after washing with ion-exchanged water at about 70 ° C. three times, it was separated and dried under an atmosphere of 120 ° C. and 0.8 to 1.0 torr for 20 hours to obtain white polyphenylene sulfide powder.
Next, this polyphenylene sulfide powder was stirred 1 to 5 times for 5 minutes to 1 hour in NMP (3 times the weight of polyphenylene sulfide polymer) at 20 to 90 ° C. in a commercially available nitrogen gas atmosphere. This polyphenylene sulfide powder was further washed four times with ion-exchanged water at about 70 ° C. and then separated and dried as described above to obtain a white polyphenylene sulfide powder. The melt viscosity at 300 ° C. of this polyphenylene sulfide powder was 5000 poise.

(2) Preparation of pellets A slurry was prepared in which spherical silica (inert particles A) having an average particle diameter of 0.6 μm was finely dispersed in ethylene glycol by 40% by weight. This slurry was mixed with the above polyphenylene sulfide powder using a Henschel mixer so that the silica content was 6.0 wt%. Next, the mixture was supplied to a twin screw extruder having two vent holes, and ethylene glycol was removed from the vent holes simultaneously with melt kneading, extruded into a gut shape, cooled in water, and then cut into particle pellets.
A slurry was prepared by finely dispersing 40% by weight of spherical silica (inert particles B) having an average particle diameter of 1.0 μm in ethylene glycol. This slurry was mixed with the above polyphenylene sulfide powder using a Henschel mixer so that the silica content was 1.0 wt%. Next, the mixture was supplied to a twin screw extruder having two vent holes, and ethylene glycol was removed from the vent holes simultaneously with melt kneading, extruded into a gut shape, cooled in water, and then cut into particle pellets.
Further, only the polyphenylene sulfide powder was melt-extruded in the same manner as described above to obtain particle-free pellets.

(Preparation of polyphenylene sulfide film roll)
Two types of the above particle pellets and non-particle pellets are mixed so that spherical silica having an average particle diameter of 0.6 μm is 0.6% by weight and spherical silica having an average particle diameter of 1.0 μm is 0.2% by weight, and 180 ° C. , Dried for 15 hours under reduced pressure of 0.5 kPa, then supplied to an extruder, extruded at a melting temperature of 330 ° C., and discharged from a die. The discharged polymer is cooled and solidified while being electrostatically applied onto a cooling drum (drum diameter 1000 mm) on which water having a thickness of 1.0 μm is uniformly applied at a surface temperature of 25 ° C., and is unstretched with a thickness of about 25 μm. A film was obtained.

  The obtained unstretched film was wound around a plurality of free rolls having a surface temperature of 95 ° C. so that the stretched section was 250 mm and stretched 3.5 times in the longitudinal direction of the film. Next, the film is stretched 3.5 times in the longitudinal and orthogonal directions of the film in a room where hot air of 100 ° C. circulates in a tenter, and then subjected to constant length heat treatment for 10 seconds in a room where hot air of 260 ° C. circulates to a thickness of about 2 μm A polyphenylene sulfide film was obtained.

This film was slit under the conditions of a speed of 130 m / min, unwinding tension of 2.5 kg / m, winding tension of 3.0 kg / m, surface pressure of 35 kg / m, using a metal contact roll as a contact roll, and a polyphenylene sulfide film roll Got.
Tables 1 and 2 show the composition, production conditions, and evaluation results of this polyphenylene sulfide film roll. Film thickness: 2.00 μm, film length: 12250 m, film roll diameter: 256 mm, air bit index: 20.7%, SRa: 49 nm, SRmax: 1132 nm. As a result of using this polyphenylene sulfide film roll, running meandering The amount was 0.2 mm and the capacitor processing yield was 98%, both of which were good results.

(Example 2)
A polyphenylene sulfide film roll was obtained in the same manner as in Example 1 except that the inert particles A were changed to spherical calcium carbonate.
Tables 1 and 2 show the composition, production conditions, and evaluation results of this polyphenylene sulfide film roll. Film thickness: 2.01 μm, film length: 4250 m, film roll diameter: 203 mm, air bite index: 23.0%, SRa: 52 nm, SRmax: 1068 nm. As a result of using this polyphenylene sulfide film roll, running meandering The amount was 0.4 mm and the capacitor processing yield was 96%, both of which were good results.

(Example 3)
A polyphenylene sulfide film roll was obtained in the same manner as in Example 1 except that the addition amount of the inert particles B was changed to 0.3% by weight.
Tables 1 and 2 show the composition, production conditions, and evaluation results of this polyphenylene sulfide film roll. Film thickness: 2.00 μm, film length: 12250 m, film roll diameter: 260 mm, air bite index: 26.9%, SRa: 64 nm, SRmax: 1260 nm. As a result of using this polyphenylene sulfide film roll, running meandering The amount was 0.6 mm and the capacitor processing yield was 91%.

(Comparative Example 1)
A polyphenylene sulfide film roll was obtained in the same manner as in Example 1 except that the average particle diameter of the inert particles A was changed to 0.1 μm.
Tables 1 and 2 show the composition, production conditions, and evaluation results of this polyphenylene sulfide film roll. Film thickness: 2.00 μm, film length: 12250 m, film roll diameter: 253 mm, air bite index: 15.8%, SRa: 28 nm, SRmax: 1027 nm. As a result of using this polyphenylene sulfide film roll, film roll Due to this blocking, the film was cut during vapor deposition, and the capacitor could not be processed.

(Comparative Example 2)
A polyphenylene sulfide film roll was obtained in the same manner as in Example 1 except that the addition amount of the inert particles A was changed to 1.0% by weight.
Tables 1 and 2 show the composition, production conditions, and evaluation results of this polyphenylene sulfide film roll. Film thickness: 2.01 μm, film length: 12250 m, film roll diameter: 262 mm, air bite index: 29.4%, SRa: 83 nm, SRmax: 954 nm. As a result of using this polyphenylene sulfide film roll, When evacuation was performed, film displacement occurred and capacitor processing could not be performed.

(Comparative Example 3)
A polyphenylene sulfide film roll was obtained in the same manner as in Example 1 except that the average particle diameter of the inert particles B was changed to 2.0 μm.
Tables 1 and 2 show the composition, production conditions, and evaluation results of this polyphenylene sulfide film roll. Film thickness: 1.96 μm, film length: 12250 m, film roll diameter: 252 mm, air bite index: 16.5%, SRa: 55 nm, SRmax: 1922 nm. As a result of using this polyphenylene sulfide film roll, running meandering The amount of 0.9 mm was satisfactory, but wrinkles were generated during capacitor processing, and the capacitor processing yield was as low as 82%.

(Comparative Example 4)
A polyphenylene sulfide film roll was obtained in the same manner as in Example 1 except that the addition amount of the inert particles B was changed to 0.03% by weight.
Tables 1 and 2 show the composition, production conditions, and evaluation results of this polyphenylene sulfide film roll. Film thickness: 2.00 μm, film length: 8500 m, film roll diameter: 236 mm, air bit index: 28.2%, SRa: 37 nm, SRmax: 983 nm. As a result of using this polyphenylene sulfide film roll, running meandering The amount was as large as 1.5 mm, and the capacitor processing yield was as low as 76%.

(Comparative Example 5)
A polyphenylene sulfide film roll was obtained in the same manner as in Example 1 except that the inert particles B were not used.
Tables 1 and 2 show the composition, production conditions, and evaluation results of this polyphenylene sulfide film roll. Film thickness: 2.02 μm, film length: 12250 m, film roll diameter: 253 mm, air bite index: 14.6%, SRa: 43 nm, SRmax: 705 nm. As a result of using this polyphenylene sulfide film roll, running meandering The amount was as large as 1.2 mm, and the capacitor processing yield was as low as 80%.

(Comparative Example 6)
An attempt was made to obtain a polyphenylene sulfide film of about 12 μm by adjusting the thickness of the unstretched film to about 150 μm using the same raw material as in Example 1, but a polyphenylene sulfide film roll can be obtained by film breakage. There wasn't.

(Comparative Example 7)
A polyphenylene sulfide film roll was obtained in the same manner as in Example 1 except that the water film was not applied to the cooling drum.
Tables 1 and 2 show the composition, production conditions, and evaluation results of this polyphenylene sulfide film roll. Film thickness: 2.05 μm, film length: 6000 m, film roll diameter: 221 mm, air bit index: 32.4%, SRa: 56 nm, SRmax: 1119 nm. As a result of using this polyphenylene sulfide film roll, When evacuation was performed, film displacement occurred and capacitor processing could not be performed.

(Comparative Example 8)
An attempt was made to obtain a polyphenylene sulfide film in the same manner as in Example 1 except that the lengthwise extending section was 40 mm, but a polyphenylene sulfide film roll could not be obtained due to film breakage.

(Comparative Example 9)
Except for using a rubber roll as a contact roll at the time of slitting, an attempt was made to obtain a polyphenylene sulfide film in the same manner as in Example 1, but wrinkles were generated in the slit and a polyphenylene sulfide film roll could not be obtained. It was.

  The polyphenylene sulfide film for capacitors of the present invention is preferably used for chip capacitors for recent small electronic devices, film capacitors for hybrid vehicles, and the like.

Claims (2)

A roll of a polyphenylene sulfide film having a film thickness of 10 μm or less, wherein an air contact index X [%] defined in the specification satisfies Formulas 1 and 2.
(Formula 1) (−2.5 × 10 ⁻⁴ × L) +22 <X <(− 2.5 × 10 ⁻⁴ × L) +32
(Formula 2) (−3.44 × 10 ⁻² × D) +26 <X <(− 3.44 × 10 ⁻² × D) +36
L: Film length [m]
D: Film roll diameter [mm] The polyphenylene sulfide film roll for a capacitor according to claim 1, wherein the film surface has a surface roughness parameter SRa of 30 to 80 nm and SRmax of 1000 to 1300 nm.