JP2010087253A - Capacitor film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a capacitor film used for an insulator of a capacitor, and excelling in breakdown withstand voltage and heat resistance even under high temperature. <P>SOLUTION: This capacitor film is formed of a propylene-based polymer composition containing: 100-50 pts.wt. of a syndiotactic propylene polymer (A); and 0-50 pts.wt. of a propylene-α-olefin copolymer (B) (in this case, the total of (A) and (B) is 100 pts.wt.). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a capacitor film used for a capacitor insulator. Specifically, the present invention relates to a capacitor film containing a specific syndiotactic propylene polymer and having excellent breakdown voltage and heat resistance even at high temperatures.

  In a capacitor film used for an insulator of a capacitor, electrical insulation (breakdown breakdown voltage) is particularly important at high temperatures, and a film having even a high breakdown breakdown voltage at high temperatures is required. In addition, with the demand for miniaturization of capacitors and an increase in capacitor capacity, capacitor films are becoming thinner, and even such thin films are desired to have a high breakdown voltage.

  On the other hand, polypropylene, one of the polymer materials, is easy to mold, has high mechanical strength, and is excellent in electrical insulation and chemical properties. Widely used as material for equipment.

  Capacitor films using polypropylene include, for example, films obtained by controlling impurities contained in the film and their amounts (Patent Documents 1 and 2, etc.), and films obtained by stretching polypropylene having specific tacticity. (Patent Documents 3 and 4) have been proposed.

However, in order to obtain a film having a high breakdown voltage, focusing on the amount of impurities in the film and reducing the amount, there is a limit to the amount of impurities, so the market demands more It is not possible to provide a film having a high breakdown voltage. In addition, a film obtained from isotactic polypropylene has a problem that the crystal (spherulite) size is large and cracks (breakage) occur due to the voltage applied to the crystal / amorphous interface.
Japanese Patent Laid-Open No. 06-236709 JP 2006-143975 A Japanese Patent Laid-Open No. 08-156118 JP 09-235325 A

  The present invention is intended to solve the problems associated with the prior art as described above, and is intended to provide a capacitor film having excellent breakdown voltage and heat resistance, which is used for a capacitor insulator even at high temperatures. Yes.

As a result of intensive studies to solve the above problems, the present inventors have found that a capacitor film comprising a specific syndiotactic propylene polymer, or a specific syndiotactic propylene polymer and a propylene / α-olefin copolymer Capacitor film made of a propylene-based polymer composition containing the above has an extremely fine crystal (spherulite) structure, and is therefore excellent in breakdown voltage and heat resistance. As a result, the present invention was completed.

That is, the present invention includes the following matters.
[1] Syndiotactic propylene polymer (A) 100 to 50 parts by weight;
0-50 parts by weight of propylene / α-olefin copolymer (B) (however, (A) and (B)
And 100 parts by weight. And a capacitor film comprising a propylene-based polymer composition comprising
A capacitor film characterized in that the syndiotactic propylene polymer (A) satisfies the following requirement (a) and the propylene / α-olefin copolymer (B) satisfies the following requirement (b).

(A): The syndiotactic pentad fraction (rrrr fraction) measured by ¹³ C-NMR is 85% or more, and the melting point (Tm) obtained from DSC is 145 ° C. or more, which is derived from propylene. The structural unit is contained in an amount exceeding 90 mol% (however, the total amount of the structural units in the syndiotactic propylene polymer (A) is 100 mol%).

(B): Containing structural units derived from propylene in an amount of 55 to 90 mol%, and 10 to 45 mol% of structural units derived from an α-olefin having 2 to 20 carbon atoms (excluding propylene) (however, The total of the structural unit derived from propylene and the structural unit derived from an α-olefin having 2 to 20 carbon atoms (excluding propylene) is 100 mol%), and in JIS K-6721 MFR measured at 230 ° C and 2.16 kg load
Is in the range of 0.01 to 100 g / 10 min and satisfies at least one of the following requirements (b-1) and (b-2).
(B-1): Syndiotactic triad fraction (rr) measured by ¹³ C-NMR method
The fraction) is 60% or more.
(B-2): The intrinsic viscosity [η] (dL / g) measured in 135 ° C. decalin and the MFR (g / 10 minutes, 230 ° C., 2.16 kg load) satisfy the following relational expression.

1.50 × MFR ^(-0.20) ≦ [η] ≦ 2.65 × MFR ^(-0.20)
[2] The capacitor film as described in [1], wherein the propylene polymer composition has a (1) needle penetration temperature of 145 ° C. or higher.

  [3] The propylene polymer composition has (1) a needle penetration temperature of 145 ° C. or higher, (2) a tensile elastic modulus in the range of 100 to 2000 MPa, and (3) the inside of a press sheet having a thickness of 1 mm. The capacitor film according to [1] or [2], wherein a haze value is 30% or less.

  [4] Melting the intrinsic viscosity [η] of the syndiotactic propylene polymer (A) measured in decalin at 135 ° C. in the range of 0.1 to 10 dL / g and determined by a differential scanning calorimeter (DSC) The capacitor film according to any one of [1] to [3], wherein a heat quantity (ΔH) is 40 mJ / mg or more.

[5] The capacitor film according to any one of [1] to [4], wherein a molecular weight distribution (Mw / Mn) obtained by GPC of the propylene / α-olefin polymer (B) is 3.5 or less.

[6] A capacitor using the capacitor film according to any one of [1] to [5].
In addition to the syndiotactic propylene polymer (A) and the propylene / α-olefin copolymer (B), the propylene polymer composition preferably further contains isotactic polypropylene.

According to the present invention, it is possible to provide a capacitor film having excellent breakdown voltage and heat resistance even at high temperatures.

The capacitor film of the present invention has a syndiotactic propylene polymer (A) of 100 to 50 parts by weight and a propylene / α-olefin copolymer (B) of 0 to 50 parts by weight (however,
The total of (A) and (B) is 100 parts by weight. And the syndiotactic propylene polymer (A) has the following requirements (a), and the propylene / α-olefin copolymer (B) has the following requirements ( It is characterized by satisfying each of b).

(A): The syndiotactic pentad fraction (rrrr fraction) measured by ¹³ C-NMR is 85% or more, and the melting point (Tm) obtained from DSC is 145 ° C. or more, which is derived from propylene. The structural unit is contained in an amount exceeding 90 mol% (however, the total amount of the structural units in the syndiotactic propylene polymer (A) is 100 mol%).

(B): Containing structural units derived from propylene in an amount of 55 to 90 mol%, and 10 to 45 mol% of structural units derived from an α-olefin having 2 to 20 carbon atoms (excluding propylene) (however, The total of the structural unit derived from propylene and the structural unit derived from an α-olefin having 2 to 20 carbon atoms (excluding propylene) is 100 mol%), and in JIS K-6721 MFR measured at 230 ° C and 2.16 kg load
Is in the range of 0.01 to 100 g / 10 min and satisfies at least one of the following requirements (b-1) and (b-2).

(B-1): The syndiotactic triad fraction (rr fraction) measured by ¹³ C-NMR method is 60% or more.
(B-2): The intrinsic viscosity [η] (dL / g) measured in 135 ° C. decalin and the MFR (g / 10 minutes, 230 ° C., 2.16 kg load) satisfy the following relational expression.

1.50 × MFR ^(-0.20) ≦ [η] ≦ 2.65 × MFR ^(-0.20)
Hereinafter, each component constituting the capacitor film of the present invention will be described in detail.

[Syndiotactic propylene polymer (A)]
The syndiotactic propylene polymer (A) used in the present invention may be a homopolypropylene or a random copolymer of propylene and an α-olefin having 2 to 20 carbon atoms (excluding propylene) Although it may be a propylene block copolymer, it is preferably a homopolypropylene or a random copolymer of propylene and an α-olefin having 2 to 20 carbon atoms (excluding propylene), particularly preferably homopolypropylene, propylene and Random copolymers of α-olefins (excluding propylene) having 2 to 10 carbon atoms or copolymers of propylene, ethylene and α-olefins having 4 to 10 carbon atoms, most preferably heat resistance and the like From the point, it is homopolypropylene.

Here, as the α-olefin having 2 to 20 carbon atoms other than propylene, ethylene,
1-butene, 3-methyl-1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1- Examples include octadecene and 1-eicosene.

The structural unit derived from propylene is contained in an amount usually exceeding 90 mol%, preferably 91 mol% or more, out of a total of 100 mol% of structural units derived from an α-olefin having 2 to 20 carbon atoms (including propylene). It is. In addition, syndiotactic propylene polymer (
When A) is a propylene / α-olefin random copolymer, it has 2 to 2 carbon atoms.
The structural unit derived from 0 α-olefin (excluding propylene) in an amount of 0.3-7 mol%, preferably 0.3-6 mol%, particularly preferably 0.3-5 mol%. Contains.

  The syndiotactic propylene polymer (A) has a syndiotactic pentad fraction (rrrr fraction, pentad syndiotacticity) measured by NMR method of 85% or more, preferably 90% or more, more preferably The syndiotactic propylene polymer (A) having 93% or more, more preferably 94% or more and having an rrrr fraction in this range is excellent in moldability, heat resistance and transparency, and is a crystalline polypropylene. It is preferable in terms of good characteristics. Moreover, since the capacitor film obtained by using the syndiotactic propylene polymer (A) has a large number of crystal nuclei per unit volume, the crystal (spherulite) size in the film is extremely small. Therefore, cracks (breakage) due to the influence of the voltage applied to the spherulite interface do not occur, and as a result, the obtained film has an excellent breakdown voltage. The upper limit of the rrrr fraction is not particularly limited, but is usually 99% or less, for example.

This syndiotactic pentad fraction (rrrr fraction) is measured as follows.
The rrrr fraction is expressed as Prrrr in the ¹³ C-NMR spectrum (absorption intensity derived from the methyl group of the third unit in a site where 5 units of propylene units are continuously syndiotactically bonded) and Pw (total methyl groups of propylene units). (Absorption intensity derived from the above) is determined by the following formula (1).

rrrr fraction (%) = 100 × Prrrr / Pw (1)
The NMR measurement is performed as follows, for example. That is, 0.35 g of a sample is dissolved by heating in 2.0 ml of hexachlorobutadiene. After this solution is filtered through a glass filter (G2), 0.5 ml of deuterated benzene is added and charged into an NMR tube having an inner diameter of 10 mm. And ¹³ C-NMR measurement is performed at 120 degreeC using the JEOL GX-500 type | mold NMR measuring apparatus. The number of integration is 10,000 times or more.

  The intrinsic viscosity [η] of the syndiotactic propylene polymer (A) measured at 135 ° C. in decalin is usually 0.1 to 10 dL / g, preferably 0.5 to 10 dL / g, more preferably 0.5. -8 dL / g, particularly preferably 0.95 to 8 dL / g, more preferably 1 to 8, still more preferably 1.4 to 8 dL / g, and still more preferably 1.4 to 5 dL / g. Especially, it is preferable that it exists in the range of 1.4-5dL / g. The syndiotactic propylene polymer (A) having such an intrinsic viscosity [η] value exhibits good fluidity, can be easily blended with other components, and is excellent in mechanical strength from the obtained composition. There is a tendency to obtain films.

Furthermore, melting | fusing point (Tm) obtained by the differential scanning calorimeter (DSC) measurement of a syndiotactic propylene polymer (A) is 145 degreeC or more, Preferably it is 147 degreeC or more, More preferably, it is 150 degreeC or more, Especially preferably, it is 155 degreeC or more, More preferably, it is 156 degreeC or more. The upper limit of Tm is not particularly limited, but is usually 170 ° C. or lower, for example. Further, the heat of fusion (ΔH) of the syndiotactic propylene polymer (A) obtained by differential scanning calorimetry (DSC) measurement is usually 40 mJ / mg or more, preferably 45 mJ / mg or more, particularly preferably 50 mJ / mg. Or more, more preferably 52 mJ / mg or more,
More preferably, it is 55 mJ / mg or more. When the heat of fusion (ΔH) is in the above range, the obtained capacitor film is preferable because it has excellent heat resistance and mechanical strength.

The differential scanning calorimeter measurement is performed as follows, for example. About 5.00 mg of sample is packed in a special aluminum pan, and DSCPyris1 or DSC7 manufactured by PerkinElmer is used.
After raising the temperature from 30 ° C. to 200 ° C. at 320 ° C./min and holding at 200 ° C. for 5 minutes, lowering the temperature from 200 ° C. to 30 ° C. at 10 ° C./min and holding at 30 ° C. for another 5 minutes, Next, the melting point (Tm) and the heat of fusion (ΔH) are determined from the endothermic curve when the temperature is raised at 10 ° C./min. When a plurality of peaks are detected during DSC measurement, the peak detected on the highest temperature side is defined as the melting point (Tm).

  The syndiotactic propylene polymer (A) having a melting point (Tm) in this range is excellent in moldability, heat resistance and mechanical properties, and has good properties as crystalline polypropylene. Therefore, by using the syndiotactic propylene polymer (A), the obtained capacitor film can have an excellent breakdown voltage even at high temperatures. The syndiotactic propylene polymer (A) having a melting point (Tm) in this range uses a catalyst system as will be described later, and by setting the polymerization conditions to be described later, the syndiotactic propylene polymer having a melting point (Tm) within this range. A tick propylene polymer (A) can be produced.

  The syndiotactic propylene polymer (A) can be produced by a polymerization method using a crosslinked metallocene compound as a polymerization catalyst. Specifically, it can be produced by the method described in International Publication No. 2006/123759.

The syndiotactic propylene polymer (A) used in the present invention is 100 to 50 parts by weight in a total of 100 parts by weight of the syndiotactic propylene polymer (A) and the propylene / α-olefin copolymer (B). Preferably it is 100-55 weight part, Most preferably, 100-60 weight part is contained. It is preferable from the viewpoint of heat resistance and mechanical strength that the content of the syndiotactic propylene polymer (A) is in the above range.

  Further, the molecular weight distribution (Mw / Mn, polystyrene conversion, Mw: weight average molecular weight, Mn: number average molecular weight) measured by GPC of the syndiotactic propylene polymer (A) is preferably 3.5 or less, more preferably It is 3.0 or less, more preferably 2.5 or less.

[Propylene / α-olefin copolymer (B)]
The propylene / α-olefin copolymer (B) used in the present invention contains a constitutional unit derived from propylene in an amount of 55 to 90 mol%, and an α-olefin having 2 to 20 carbon atoms (
The structural unit derived from (except for propylene) is contained in an amount of 10 to 45 mol%.

When used in the present invention, when the syndiotactic propylene polymer (A) is contained in 50 parts by weight or more in a total of 100 parts by weight of (A) and (B), propylene / α-
The olefin copolymer (B) contains 55 to 90 mol%, preferably 55 to 85 mol%, more preferably 60 to 85 mol% of a structural unit derived from propylene and an α-carbon atom having 2 to 20 carbon atoms.
It contains 10 to 45 mol%, preferably 15 to 45 mol%, more preferably 15 to 40 mol% of structural units derived from olefins (excluding propylene). On the other hand, when the content of the syndiotactic propylene polymer (A) is less than 50 parts by weight in a total of 100 parts by weight of (A) and (B), the propylene / α-olefin copolymer (B) is propylene A structural unit derived from 55 to 90 mol%, preferably 65 to 85 mol%, more preferably 70 to 85 mol%, and an α-olefin having 2 to 20 carbon atoms (excluding propylene). It contains 10 to 45 mol%, preferably 15 to 35 mol%, more preferably 15 to 30 mol%.

The total of structural units derived from propylene and structural units derived from an α-olefin having 2 to 20 carbon atoms (excluding propylene) is 100 mol%.
Examples of the α-olefin having 2 to 20 carbon atoms (excluding propylene) include ethylene, 3-methyl-1-butene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, Examples include 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene and 1-eicocene. Particularly preferred are ethylene, 1-butene, 1-hexene, 4-methyl-1-pentene and 1-octene.

Of the propylene / α-olefin copolymer (B), a propylene / ethylene copolymer is preferable, and a structural unit derived from propylene, a structural unit derived from ethylene, 1-butene, A structural unit derived from ethylene, comprising a structural unit derived from at least one monomer selected from 1-hexene, 4-methyl-1-pentene and 1-octene (hereinafter also referred to as “HAO comonomer”). A propylene / ethylene / HAO copolymer is used in which the ratio (mol%) is greater than the ratio (mol%) of structural units derived from the HAO comonomer.

The propylene / α-olefin copolymer (B) used in the present invention is JIS K-67.
The MFR measured at 230 ° C. and 2.16 kg load in accordance with 21 is 0.01 to 100 g /
And satisfies any one or more of the following requirements (b-1) and (b-2).

(B-1): The syndiotactic triad fraction (rr) measured by ¹³ C-NMR method is 60% or more.
(B-2): Intrinsic viscosity [η] (dL / g) measured in 135 ° C. decalin and MFR (g / 10 min) measured at 230 ° C. and 2.16 kg load according to JIS K-6721 Satisfies the following relational expression.

1.50 × MFR ^(-0.20) ≦ [η] ≦ 2.65 × MFR ^(-0.20)
The propylene / α-olefin copolymer (B) preferably has an MFR measured at 230 ° C. under a load of 2.16 kg in accordance with JIS K-6721 in the range of 0.01 to 100 g / 10 min. More preferably, it is in the range of 0.02 to 100 g / 10 min.

The requirement (b-1) will be described below.
(B-1): Propylene / α-olefin copolymer (B) has a syndiotactic triad fraction (rr fraction, triad syndiotacticity) measured by ¹³ C-NMR method of 60% or more, preferably The propylene / α-olefin copolymer (B) having a ratio of rr in this range of 70% or more, more preferably 75% or more is preferable because it has good compatibility with the syndiotactic propylene polymer (A). .

  The polymer satisfying (b-1) can be obtained, for example, by copolymerization of propylene and α-olefin in the presence of a catalyst capable of producing syndiotactic polypropylene, or a catalyst as described later is used. Can also be manufactured.

The rr fraction is Prr in the ¹³ C-NMR spectrum (absorption intensity derived from the methyl group of the second unit at the site where three units of propylene units are continuously syndiotactically bonded) and Pw (total methyl groups of propylene units). (Absorption intensity derived from the above) is determined by the following formula (2).

rr fraction (%) = 100 × Prr / Pw (2)
Here, absorption derived from mr (used to determine Pmr (absorption intensity), absorption derived from at least syndiotactic bond and isotactic bond among 3 units of propylene unit), absorption derived from rr ( Absorption derived from the methyl group of the second unit at a site where 3 units of propylene units are continuously syndiotactically bonded, used for determination of Prr (absorption intensity)), or absorption derived from mm (3 units of propylene units are continuous) If the absorption derived from the methyl group of the second unit at the isotactic bond site and the absorption derived from the comonomer overlap with the absorption derived from the second unit methyl group, the contribution of the comonomer component Calculate without any deduction.

Specifically, among the descriptions of how to obtain the “syndiotacticity parameter (SP value)” described in paragraphs [0018] to [0031] of JP-A-2002-097325, [00
18] to [0023] paragraphs are performed, and calculation is performed by the above equation (2) from the integrated intensity of signals in the first region, the second region, and the third region.

In the present invention, the rr ₁ value is obtained particularly according to the method for obtaining the “syndiotacticity parameter (SP value)” described in paragraphs [0018] to [0031] of JP-A-2002-097325. More preferably, the value is 60% or more, preferably 65% or more, more preferably 70% or more. In other words, in the calculation of the rr value, the rr ₁ value is the absorption of mr (absorption derived from at least both syndiotactic and isotactic bonds out of 3 units of propylene units, Pmr (absorption intensity)). Used for determination), absorption derived from rr (absorption derived from the methyl group of the second unit at a site where three units of propylene units are continuously syndiotactically bonded, used for determination of Prr (absorption intensity)), or mm Absorption derived from (absorption derived from the methyl group of the second unit at a site where 3 units of propylene units are continuously isotactically bonded, intensity used for determining Pmm (absorption intensity)), and absorption derived from a comonomer In the case of overlapping, the contribution of the comonomer component is subtracted.

In the measurement of the rr value and the rr ₁ value, the NMR measurement is performed, for example, as follows. That is, 0.35 g of a sample is dissolved by heating in 2.0 ml of hexachlorobutadiene. After this solution is filtered through a glass filter (G2), 0.5 ml of deuterated benzene is added and charged into an NMR tube having an inner diameter of 10 mm. Then, ¹³ C-NMR measurement is performed at 120 ° C. using a GX-400 NMR measurement apparatus manufactured by JEOL. The number of integration is 8,000 times or more.

Next, requirement (b-2) will be described.
(B-2): The propylene / α-olefin copolymer (B) has an intrinsic viscosity [η] (dL / g) measured in decalin of 135 ° C. and 230 ° C. according to JIS K-6721. The MFR (g / 10 minutes) measured with a 2.16 kg load satisfies the following relational expression.

1.50 × MFR ^(-0.20) ≦ [η] ≦ 2.65 × MFR ^(-0.20)
More preferably 1.80 × MFR ^(−0.20) ≦ [η] ≦ 2.50 × MFR ^(−0.19)
The propylene / α-olefin copolymer (B) satisfying this relational expression is preferable because it has good compatibility with the syndiotactic propylene polymer (A).

The propylene / α-olefin copolymer (B) satisfying the above formula may be obtained by copolymerizing propylene and α-olefin using a catalyst capable of producing a syndiotactic propylene polymer, for example. You may superpose | polymerize using a catalyst. The propylene / α-olefin copolymer (B) thus obtained is a syndiotactic propylene polymer (A).
And good compatibility.

The propylene / α-olefin copolymer (B) satisfying (b-2) has the same intrinsic viscosity [η] and a high MFR value as compared with the conventional isotactic propylene-based copolymer.

  This is described in “Macromolecules” 1998, Vol. 31, p. The molecular weight between entanglement points of isotactic polypropylene (reported as Me = 6900 (g / mol) in the paper) and the molecular weight between entanglement points of syndiotactic polypropylene as described in 1335-1340. In this case, it is considered that this is caused by a difference from Me = 2170 (g / mol). That is, when [η] is the same, having a syndiotactic structure increases the number of entanglement points as compared with a material having an isotactic structure, and thus the MFR value is considered to be high.

As described above, the propylene / α-olefin copolymer (B) satisfying any one or more of the requirements (b-1) and (b-2) is a steric rule different from the isotactic structure. It is considered to have a syndiotactic structure that is a sex. Therefore, it is considered that the propylene / α-olefin copolymer (B) exhibits good compatibility with the component (A).

The propylene / α-olefin copolymer (B) is a preferred embodiment of propylene / α-olefin copolymer (B).
In the ethylene copolymer and the propylene / ethylene / HAO copolymer, it is preferable to satisfy both of the above requirements (b-1) and (b-2).

The intrinsic viscosity [η] of the propylene / α-olefin copolymer (B) measured in decalin at 135 ° C. is 0.1 to 10 dL / g, preferably 0.5 to 10 dL / g, more preferably 0.8. It is desirable to be 5 to 7.0 dL / g.

This propylene / α-olefin copolymer (B) has a single glass transition temperature, and the glass transition temperature (Tg) obtained by differential scanning calorimetry (DSC) measurement is usually 0 ° C. or lower. It is preferable. Glass transition temperature of propylene / α-olefin copolymer (B) (
When Tg) is within the above range, the cold resistance and the low temperature characteristics are excellent.

The differential scanning calorimetry is performed as follows, for example. About 10.00 mg of the sample is packed in a special aluminum pan, and the temperature is increased from 30 ° C. to 200 ° C. at 200 ° C./min using a DSCRDC220 manufactured by Seiko Instruments Inc. After holding at 200 ° C. for 5 minutes, from 200 ° C. The temperature is lowered to −100 ° C. at 10 ° C./min, held at −100 ° C. for another 5 minutes, and then the glass transition temperature (Tg) is determined from the endothermic curve when the temperature is raised at 10 ° C./min.

Moreover, the molecular weight distribution (Mw / Mn, polystyrene conversion, Mw: weight average molecular weight, Mn: number average molecular weight) measured by GPC of this propylene / α-olefin copolymer (B) is preferably 3.5 or less. More preferably, it is 3.0 or less, More preferably, it is 2.5 or less.

The propylene / α-olefin copolymer (B) can be produced by a polymerization method using a crosslinked metallocene compound as a polymerization catalyst. Specifically, it can be produced by the method described in International Publication No. 2006/123759.

The propylene / α-olefin copolymer (B) used in the present invention is a total of 1 of the syndiotactic propylene polymer (A) and the propylene / α-olefin copolymer (B).
In 00 parts by weight, 0 to 50 parts by weight, preferably 0 to 45 parts by weight, particularly preferably 0 to 40 parts by weight are contained. When the content of the propylene / α-olefin copolymer (B) is in the above range, it is preferable from the viewpoint of heat resistance and mechanical strength.

[Isotactic polypropylene]
The propylene polymer composition comprising the syndiotactic propylene polymer (A) and the propylene / α-olefin copolymer (B) according to the present invention may contain isotactic polypropylene as necessary. Good. Isotactic polypropylene is preferable because it can further improve the heat resistance of the capacitor film of the present invention.

  As the isotactic polypropylene, commercially available ones can be used without particular limitation, but the isotactic pentad fraction measured by NMR method is 0.9 or more, preferably 0.95 or more. It is preferable to use polypropylene.

  Specific examples include a propylene homopolymer or a copolymer of propylene and an α-olefin having 2 to 20 carbon atoms other than propylene. Examples of the α-olefin having 2 to 20 carbon atoms other than propylene include ethylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene and 1-dodecene. , 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene and the like. Among them, ethylene or an α-olefin having 4 to 10 carbon atoms is preferable. These α-olefins may form a random copolymer with propylene or a block copolymer. The structural unit derived from these α-olefins may be contained in isotactic polypropylene at a ratio of 40 mol% or less, preferably 20 mol% or less.

  The melt flow rate (MFR) measured at 230 ° C. under a load of 2.16 kg in accordance with ASTM D 1238 of isotactic polypropylene is usually 0.01 to 1000 g / 10 minutes, preferably 0.05 to 500 g / 10 minutes. Range.

  The isotactic polypropylene is, for example, a Ziegler catalyst comprising (a) a solid catalyst component containing magnesium, titanium, halogen and an electron donor as essential components, (b) an organoaluminum compound, and (c) an electron donor. It can manufacture by superposing | polymerizing using a system. It can also be produced similarly using a metallocene catalyst.

  The isotactic polypropylene is preferably a propylene / ethylene random copolymer or a propylene / ethylene block copolymer having a good balance of whitening resistance and impact resistance among polypropylene copolymers produced by a Ziegler catalyst.

[Other ingredients]
The propylene-based polymer composition used in the present invention includes a weather resistance stabilizer, a heat resistance stabilizer, an antistatic agent, an anti-slip agent, an antiblocking agent, an antifogging agent, and a nucleating agent as long as the object of the invention is not impaired. Additives such as lubricants, pigments, dyes, plasticizers, anti-aging agents, hydrochloric acid absorbents and antioxidants may be blended as necessary.

[Propylene-based polymer composition]
The propylene polymer composition obtained as described above is excellent in moldability and heat resistance, and further excellent in transparency, flexibility and scratch resistance.

  Here, “excellent formability” means that when molding such as injection, inflation, blow, extrusion, or press is performed, the time from solidification to solidification is short. When moldability is good, it is excellent in moldability, shape stability, long-term productivity, and the like.

Specifically, the needle penetration temperature (hereinafter also referred to as “physical property (1)”) measured for the propylene-based polymer composition used in the present invention is preferably 145 ° C. or higher, more preferably 147 ° C., particularly Preferably it is 150 degreeC or more. When the needle penetration temperature is in the above range, the obtained capacitor film is preferable because it has excellent heat resistance. The needle penetration temperature (sometimes referred to as the softening point determined by TMA measurement) can be measured as follows. That is, using a Seiko SS-120 or TA Instrument Q-400, a press sheet test piece having a thickness of 1 mm and a flat indenter of 1.8 mmφ at a heating rate of 5 ° C./min is 2 Kgf / cm. A pressure of ² was applied, and the needle penetration temperature (° C.) was determined from the TMA curve.

Moreover, the measuring method of a tensile elasticity modulus (henceforth "physical property (2)") and haze (henceforth "physical property (4)") is shown below.
Tensile modulus is 1 mm thick press sheet according to JIS K6301 and JIS K6301
It was punched out with a No. 3 dumbbell order bell and used as an evaluation sample. For the measurement, for example, using an Instron tensile tester Inston 1123, measurement was performed at 23 ° C. with a span interval of 30 mm and a tensile speed of 30 mm / min, and an average value of three times was obtained.

Internal haze (hereinafter also referred to as “physical property (3)”) was measured with a digital turbidimeter “NDH-20D” manufactured by Nippon Denshoku Industries Co., Ltd., using a 1 mm thick press sheet test piece. The average value of times was used.

  In each of the above tests, the test piece was heated in a press molding machine at 200 ° C. for 5 to 10 minutes, then molded in 1 to 2 minutes under 10 MPa pressure, and then cooled at 20 ° C. under 10 MPa pressure. It was obtained by preparing a sheet having a predetermined thickness.

The time until solidification is a half crystallization time (t _1/2 ) (hereinafter also referred to as “physical property (4)”) obtained from isothermal crystallization measurement at 110 ° C. with a thermal differential calorimeter (DSC). Preferably it is 1000 sec or less, More preferably, it is 500 sec or less. The propylene-based polymer composition used in the present invention contains a specific syndiotactic propylene polymer (A) and a propylene / α-olefin copolymer (B), so that t _1/2 is higher than that of the prior art. It has been dramatically improved and can be molded by the same molding method as that of normally used isotactic polypropylene. Therefore, the capacitor film of the present invention can be easily thinned, and can meet the demand for miniaturization of capacitors and increase in capacitor capacity.

The half crystallization time (t _1/2 ) determined by isothermal crystallization measurement is the D in the isothermal crystallization process.
When the area between the SC calorie curve and the baseline is defined as the total calorific value, it is the time to reach 50% calorific value (see New Polymer Experiment Course 8, Physical Properties of Polymers (Kyoritsu Shuppan Co., Ltd.)). The half crystallization time (t _1/2 ) is measured as follows. That is, about 5.00 mg of a sample is packed in a dedicated aluminum pan, heated to 320 ° C./min from 30 ° C. to 200 ° C. using DSCPyris 1 or DSC 7 manufactured by Perkin Elmer, and held at 200 ° C. for 5 minutes, and then 200 It was obtained from a DSC curve obtained by lowering the temperature from 320 ° C. to an isothermal crystallization temperature of 110 ° C. at 320 ° C./min and maintaining the temperature at 110 ° C. Here, the half crystallization time (t _1/2 ) was determined by assuming that the isothermal crystallization process start time at 110 ° C. (time when the temperature reached from 110 ° C. to 110 ° C.) t = 0. The propylene-based polymer composition used in the present invention can determine t _1/2 as described above, but when it does not crystallize at 110 ° C., it is conveniently measured at an isothermal crystallization temperature of 110 ° C. or less. The half crystallization time (t _1/2 ) is obtained from the extrapolated value.

In the case of the propylene-based polymer composition used in the present invention, the α-olefin (excluding propylene) having 2 to 20 carbon atoms of the propylene / α-olefin copolymer (B) is ethylene or ethylene and HAO. A combination with a comonomer is preferred, with ethylene being particularly preferred. The structural unit derived from α-olefin is more preferably 15 to 45 mol%, and particularly preferably 15 to 40 mol%. Within this range, the propylene polymer composition used in the present invention is particularly excellent in the balance between heat resistance, transparency and impact resistance.

In the case of the propylene-based polymer composition, the needle penetration temperature (1) is preferably 145 ° C or higher, more preferably 147 ° C or higher;
The tensile modulus (2) is preferably in the range of 100 MPa to 2000 MPa, more preferably in the range of 200 MPa to 1500 MPa, and still more preferably in the range of 400 MPa to 1000 MPa;
The internal haze (3) is preferably 30% or less, more preferably 25% or less;
The half crystallization time (4) is preferably 1000 sec or less, more preferably 500 sec or less.

  When the above-mentioned physical properties (1) to (3) are in the above-mentioned range, the obtained capacitor film has an excellent heat resistance and transparency, so that the above-mentioned physical properties (1) to (4) are preferable. When it exists in the above-mentioned range, since the obtained capacitor film has the outstanding heat resistance, transparency, and moldability, it is especially preferable.

[Capacitor film and capacitor]
The capacitor film of the present invention is a propylene-based polymer comprising a syndiotactic propylene polymer (A), a propylene / α-olefin copolymer (B) and, if necessary, the above isotactic polypropylene and various additives. The polymer composition can be obtained by stretching a raw sheet obtained by melt extrusion in the range of 180 to 300 ° C. uniaxially or biaxially.

  Since the capacitor film of the present invention does not have spherulites in the film as described above, it is excellent in breakdown voltage and heat resistance, so it is in the range of 0 to 120 ° C, preferably 0 to 90 ° C. In the range, it can be suitably used as an insulator for capacitors. The breakdown voltage of the capacitor film of the present invention is 600 V / μm or more, preferably 650 V / μm or more.

  The apparatus for obtaining the capacitor film of the present invention is not particularly limited. For example, in the case of uniaxial stretching, the above-described raw sheet is used in a machine direction (raw direction) at 100 to 160 ° C. using a batch type biaxial stretching machine. It can be obtained by stretching in a direction parallel to the flow of the resin to be extruded when forming the anti-sheet. In biaxial stretching, the film obtained by uniaxial stretching is further stretched sequentially at right angles to the machine direction under the same conditions as in uniaxial stretching, or simultaneously stretched in the direction perpendicular to the machine direction and machine direction. It can be obtained by performing biaxial stretching.

  Industrially, the tubular film method (a method in which a molten polymer extruded from an extruder is simultaneously stretched on both axes as a tube) or the tenter method (the molten polymer extruded from an extruder is cooled with a cooling roll). It is uniaxial using a continuous biaxial stretching method in which the film is solidified and stretched in the longitudinal direction with a plurality of preheating rolls and a plurality of longitudinal stretching rolls, and subsequently introduced into a transverse stretching apparatus (tenter) and stretched in the transverse direction. Alternatively, a biaxially stretched film can be obtained.

In the tenter method, a melt film melt-extruded from a T-die is solidified with a cooling roll, and the melt-formed film is preheated as necessary, and then introduced into a stretching zone, and then at a temperature of 100 to 160 ° C. in the longitudinal direction from 1.5 to Stretched 8 times. This draw ratio is 1.5 to 8 times, preferably 2 to 7 times. If it is lower than 1.5 times, the film strength does not increase, and if it exceeds 8 times, voids are likely to occur, and the strength in the width direction is low. It becomes easy to tear in the length direction. Next, the film is further stretched 6 to 12 times in the width direction at a temperature of 120 to 170 ° C. Finally, the biaxially stretched film is heat-set at 160 to 190 ° C. if necessary.

  The capacitor film of the present invention itself has a very high electrical insulation property. However, a film obtained by biaxial stretching has a high mechanical strength and can be manufactured from a thin to a thick material.

  In addition, the thickness of the capacitor film of the present invention is arbitrarily determined according to its use and is not particularly limited, but is usually 1 to 200 μm, preferably 3 to 100 μm, particularly a thin film of 20 μm or less, preferably Shows a better electrical characteristic (breakdown withstand voltage) than when a known material is used when the capacitor film has a film thickness of 15 μm or less, more preferably 10 μm or less.

  In the present invention, the above capacitor film can be used for a known capacitor. As described above, since the capacitor film of the present invention exhibits a high breakdown voltage even in a thin film, a high capacitor capacity can be obtained even in a small capacitor.

In the present invention, the breakdown voltage can be measured by the following method.
In accordance with JIS-2330, using a direct current withstand voltage tester manufactured by Kasuga Electric Co., Ltd., with a voltage increase of 500 V / sec, a voltage was applied to the film to measure a breakdown withstand voltage, and a withstand voltage characteristic was obtained. The breakdown withstand voltage is obtained by dividing the measured value (V) of the breakdown withstand voltage by the thickness (μm) of the film.

  Capacitor film required for the measurement was obtained by extruding pellets obtained from the propylene polymer composition at 200 to 230 ° C. to prepare a sheet-like film having a thickness of 250 μm, and this film was further biaxially stretched by TM Long. Using a machine, a biaxially stretched film having a thickness of 4 μm was prepared by first stretching 5 times in the MD direction and then 5 times in the TD direction at 140 to 150 ° C. 50 pieces of this film having a size of 150 mm × 150 mm were used, and the measurement location of the test piece was limited to one location.

  The measurement method is as follows. The upper electrode is a 25 mmφ well polished brass cylinder with 3 mm roundness on the periphery (+) electrode, and the lower electrode is about 150 mm × 150 mm on a 30 mm thick metal plate An aluminum foil having a thickness of 0.007 mm or more and a width of 80 mm as defined in JIS-H-4160 was wrapped around an elastic plate having a rubber shore of 60 to 70 degrees, and this was used as a (−) electrode.

〔Example〕
EXAMPLES Hereinafter, although this invention is demonstrated further more concretely based on an Example, this invention is not limited to these Examples. In the examples, each physical property was measured as follows.

Physical property measurement method [Intrinsic viscosity [η]]
It measured at 135 degreeC using the decalin solvent. That is, about 20 mg of polymer powder, pellets or resin mass is dissolved in 15 ml of decalin, and the specific viscosity ηsp is measured in an oil bath at 135 ° C. After adding 5 ml of decalin solvent to this decalin solution for dilution, the specific viscosity η _sp is measured in the same manner. This dilution operation was further repeated twice, and the value of η _sp / C when the concentration (C) was extrapolated to 0 was determined as the intrinsic viscosity (see the following formula).

[Η] = lim (η _sp / C) (C → 0)
[Amount of soluble part of n-decane]
Add 200ml of n-decane to 5g sample of syndiotactic propylene polymer (A),
The polymer was dissolved by heating at 145 ° C. for 30 minutes. The resulting solution was allowed to cool to 20 ° C. over about 3 hours and left for 30 minutes. Thereafter, the precipitate (n-decane insoluble part) was filtered off. The filtrate was put in about 3 times the amount of acetone to precipitate the components dissolved in n-decane. The precipitate was filtered off from acetone and then dried. Even when the filtrate side was concentrated to dryness, no residue was observed. The amount of n-decane soluble part was determined by the following equation.

n-decane soluble part amount (wt%) = [precipitate weight / sample weight] × 100
[Molecular weight distribution (Mw / Mn)]
The molecular weight distribution (Mw / Mn) was measured as follows using a gel permeation chromatograph Alliance GPC-2000 manufactured by Waters. The separation columns are two TSKgel GNH6-HT and two TSKgel GNH6-HTL, the column size is 7.5 mm in diameter and 300 mm in length, the column temperature is 140 ° C., and the mobile phase is o -Use dichlorobenzene (Wako Pure Chemical Industries) and 0.025% by weight of BHT (Takeda Pharmaceutical) as an antioxidant, move at 1.0 ml / min, set the sample concentration to 15 mg / 10 mL, and set the sample injection volume to 500 μL A differential refractometer was used as a detector. The standard polystyrene used was manufactured by Tosoh Corporation for molecular weights of Mw <1000 and Mw> 4 × 10 ⁶ , and used by Pressure Chemical Co. for 1000 ≦ Mw ≦ 4 × 10 ⁶ .

[Ethylene, propylene, α-olefin content in polymer]
Quantification of ethylene, propylene, and α-olefin content was measured as follows using a JNM GX-400 NMR measuring apparatus manufactured by JEOL Ltd. A 0.35 g sample is dissolved by heating in 2.0 ml of hexachlorobutadiene. The solution is filtered through a glass filter (G2), 0.5 ml of deuterated benzene is added, and the solution is placed in an NMR tube having an inner diameter of 10 mm, and ¹³ C-NMR measurement is performed at 120 ° C. The number of integration is 8,000 times or more. The composition of ethylene, propylene, and α-olefin was quantified by the obtained ¹³ C-NMR spectrum.

[Melting point (Tm) of component (A), heat of fusion (ΔH)]
Using a DSCPyris 1 or DSC7 manufactured by PerkinElmer, under a nitrogen atmosphere (20
ml / min), about 5 mg of sample was heated to 200 ° C. and held for 10 minutes, and then cooled to 30 ° C. at 10 ° C./min. After maintaining at 30 ° C. for 5 minutes, the melting point was calculated from the peak of the crystal melting peak when the temperature was raised to 200 ° C. at 10 ° C./min, and the heat of fusion was calculated from the integrated value of the peak.

In addition, when two peaks are observed in the propylene polymer described in the examples, the low temperature side peak is Tm ₁ and the high temperature side peak is Tm ₂ . Tm defined in the appended claims 1 (a) is a Tm _2.

[Stereoregularity rrrr]
Stereoregularity (rrrr) was calculated from ¹³ C-NMR spectrum measurement.
[Glass point transfer (Tg) of component (B), melting point (Tm)]
Using a DSC manufactured by Seiko Instruments Inc., about 5 mg of sample was packed in a measurement aluminum pan, heated to 200 ° C. at 100 ° C./min, held at 200 ° C. for 5 min, and then −150 at 10 ° C./min. It was determined from an endothermic curve where the temperature was lowered to 200C and then raised to 200 ° C at 10 ° C / min.

[MFR]
The MFR of the syndiotactic propylene polymer (A) and the propylene / α-olefin copolymer (B) was measured at 230 ° C. under a load of 2.16 kg according to JIS K-6721.

[density]
Density measurement was performed according to ASTM D1505.
[Dielectric breakdown voltage (BDV]]
The dielectric breakdown voltage (V / μm) was measured at 23 ° C. and 80 ° C. according to the B method (plate electrode method) described in JIS-C2330. The voltage increase rate was 500 V / sec.

Catalyst synthesis example [Synthesis Example 1]
Dibenzylmethylene (cyclopentadienyl) (3,6-ditert-butylfluorenyl) zirconium dichloride was produced by the method described in Synthesis Example 3 of Japanese Patent Application Laid-Open No. 2004-189666.

Polymerization Example <Polymerization Example 1> Production of Syndiotactic Propylene Polymer (A-1) 250 ml of toluene was placed in a 500 ml glass autoclave sufficiently purged with nitrogen, and propylene was circulated in an amount of 150 L / hour. And kept at 25 ° C. for 20 minutes. On the other hand, a magnetic stirrer was placed in a 30 ml-branch flask with sufficient nitrogen substitution, and 5.00 mmol of a toluene solution of methylaluminoxane (Al = 1.53 mol / l), followed by dibenzylmethylene (cyclopentadienyl). ) 5.0 μmol of toluene solution of (3,6-di-tert-butylfluorenyl) zirconium dichloride was added and stirred for 20 minutes. This solution was added to toluene in a glass autoclave in which propylene had been circulated, and polymerization was started. Propylene gas was continuously supplied at a rate of 150 liters / hour, polymerization was carried out at 25 ° C. under normal pressure for 45 minutes, and then a small amount of methanol was added to stop the polymerization. The polymer solution was added to a large excess of methanol to precipitate the polymer and dried under reduced pressure at 80 ° C. for 12 hours. As a result, 2.38 g of polymer was obtained. The polymerization activity is 0.63 kg-PP / mmol-Zr · hr. [Η] of the obtained polymer is 1.9 dl / g, Tm ₁ = 152 ° C., Tm ₂ = 158 ° C., rrrr = 94% It was Mw / Mn = 2.0. This operation was repeated to obtain the required amount of polymer and used in the examples.

The results are shown in Table 1.
<Polymerization Example 2> Production of Propylene / α-Olefin Copolymer (B-1) After charging 1834 ml of dry hexane and triisobutylaluminum (1.0 mmol) to a 4000 ml polymerization apparatus sufficiently purged with nitrogen at room temperature. The internal temperature of the polymerization apparatus was raised to 70 ° C., and the pressure in the system was increased to 0.66 MPa with propylene, and then the system pressure was adjusted to 1.36 MPa with ethylene. Next, 0.001 mmol of di (p-chlorophenyl) methylene (cyclopentadienyl) (octamethyloctahydrodibenzofluorenyl) zirconium dichloride and 0.3 mmol of methylaluminoxane (produced by Tosoh Finechem) in terms of aluminum are brought into contact. The toluene solution was added to the polymerization vessel and polymerized for 15 minutes while maintaining the internal temperature at 70 ° C. and the internal pressure at 1.36 MPa with ethylene, and 20 ml of methanol was added to terminate the polymerization. After depressurization, the polymer was precipitated from the polymerization solution in 4 L of methanol and dried under vacuum at 130 ° C. for 12 hours. The obtained polymer was 105 g, the MFR was 1.0 (g / 10 min), and [η] = 2.5 (dL / g) measured in decalin at 135 ° C. The rr ₁ value was 78%.

  The results are shown in Table 1.

(1) Pelletization With respect to 100 parts by weight of the obtained polymer (A-1), 0.2 parts by weight of 3,5-di-t-butyl-4-hydroxytoluene as an antioxidant and tetrakis [ Methylene-3 (3,5-di-t-butyl-4-hydroxyphenyl) propionate] 0.2 parts by weight of methane and 0.01 parts by weight of calcium stearate as a neutralizing agent were blended, and a resin was obtained using a twin screw extruder. Pelletization was performed by melt-kneading at a temperature of 200 ° C.

(2) Sheet Molding The pellets obtained above were melt cast molded at a die temperature of 200 ° C. using a uniaxial sheet molding machine to perform sheet molding.

(3) Biaxially stretched film The sheet obtained in (2) above was cut into 85 mm x 85 mm and biaxially stretched under the following conditions to obtain a biaxially stretched film having a thickness of 15 µm.

Stretching device: KARO IV manufactured by Bruckner
Preheating temperature: 142 ° C
Preheating time: 30 seconds Stretch ratio: 5 × 5 times (MD direction: 5 times, TD direction: 7 times) Simultaneous biaxial stretching Stretching speed: 10 m / min
Table 2 summarizes the physical properties measured for the obtained pellets, film, and capacitors wound with the film and aluminum foil.

It was carried out in the same manner as in Example 1 except that a polymer blended from (A-1) to polymer (A-1) and polymer (B-1) at a predetermined ratio was used. The results are summarized in Table 2.
[Comparative Example 1]

The polymer to be used is changed from (A-1) to Syndiotactic polypropylene (trade name: Total Polypropylene 1251) (C-1) manufactured by Total,
It carried out like Example 1 except having changed the preheating temperature at the time of biaxially stretched film preparation into 116 degreeC. The results are summarized in Table 2.
[Comparative Example 2]

The polymer used is changed from (A-1) to isotactic polypropylene (product name: F-133) (D-1) manufactured by Prime Polymer Co., and the preheating temperature during biaxially stretched film production is changed to 154 ° C. The procedure was the same as in Example 1 except that. The results are summarized in Table 2.
[Comparative Example 3]

  It was carried out in the same manner as in Example 1 except that a polymer blended from (A-1) to polymer (A-1) and polymer (B-1) at a predetermined ratio was used. The results are summarized in Table 2.

Claims (6)

100-50 parts by weight of syndiotactic propylene polymer (A),
0-50 parts by weight of propylene / α-olefin copolymer (B) (however, (A) and (B)
And 100 parts by weight. And a capacitor film comprising a propylene-based polymer composition comprising
A capacitor film characterized in that the syndiotactic propylene polymer (A) satisfies the following requirement (a) and the propylene / α-olefin copolymer (B) satisfies the following requirement (b).
(A): The syndiotactic pentad fraction (rrrr fraction) measured by ¹³ C-NMR is 85% or more, and the melting point (Tm) obtained from DSC is 145 ° C. or more, which is derived from propylene. The structural unit is contained in an amount exceeding 90 mol% (however, the total amount of the structural units in the syndiotactic propylene polymer (A) is 100 mol%).
(B): Containing structural units derived from propylene in an amount of 55 to 90 mol%, and 10 to 45 mol% of structural units derived from an α-olefin having 2 to 20 carbon atoms (excluding propylene) (however, The total of the structural unit derived from propylene and the structural unit derived from an α-olefin having 2 to 20 carbon atoms (excluding propylene) is 100 mol%), and in JIS K-6721 MFR measured at 230 ° C and 2.16 kg load
Is in the range of 0.01 to 100 g / 10 min and satisfies at least one of the following requirements (b-1) and (b-2).
(B-1): The syndiotactic triad fraction (rr fraction) measured by ¹³ C-NMR method is 60% or more.
(B-2): The intrinsic viscosity [η] (dL / g) measured in 135 ° C. decalin and the MFR (g / 10 minutes, 230 ° C., 2.16 kg load) satisfy the following relational expression.
1.50 × MFR ^(-0.20) ≦ [η] ≦ 2.65 × MFR ^(-0.20) 2. The capacitor film according to claim 1, wherein (1) the needle penetration temperature of the propylene-based polymer composition is 145 ° C. or higher. (1) The needle penetration temperature of the propylene-based polymer composition is 145 ° C. or higher,
(2) The tensile modulus is in the range of 100 to 2000 MPa,
(3) The capacitor film according to claim 1 or 2, wherein the press sheet having a thickness of 1 mm has an internal haze value of 30% or less.   The intrinsic viscosity [η] of the syndiotactic propylene polymer (A) measured in decalin at 135 ° C. is in the range of 0.1 to 10 dL / g, and the heat of fusion (ΔH ) Is 40 mJ / mg or more, The capacitor film according to any one of claims 1 to 3. Molecular weight distribution (Mw) determined by GPC of the propylene / α-olefin polymer (B).
/ Mn) is 3.5 or less, The capacitor film as described in any one of Claims 1-4 characterized by the above-mentioned.   The capacitor using the capacitor film as described in any one of Claims 1-5.