JP7144256B2 - Polypropylene-based resin composition for capacitor film and capacitor film comprising the same - Google Patents

Description

The present invention relates to a propylene-based resin composition for capacitor films and a capacitor film comprising the same. More specifically, the present invention relates to a propylene-based resin composition capable of producing a capacitor film excellent in high-temperature voltage resistance and thin film stretchability, and a capacitor film comprising the same.

Biaxially oriented polypropylene film is excellent in mechanical properties, heat resistance, transparency, chemical stability, and electrical properties. Widely used in various fields. In particular, stretched polypropylene films for capacitors are used not only as high-voltage capacitors, but also as noise filter capacitors and smoothing capacitors for switching power supplies, converters, inverters, and the like.

For these uses, miniaturization and higher capacity of capacitors are required. In addition, when capacitors are used under high output conditions, such as in hybrid cars and electric vehicles, large currents flow through circuits such as transistors and capacitors, raising operating temperatures. It has been demanded.

Thinning the film is an effective way to reduce the size and increase the capacity of the capacitor. However, when the film is thinned, the withstand voltage at high temperature is remarkably lowered, and the dielectric breakdown of the capacitor film occurs at low voltage when the capacitor is used. On the other hand, from the viewpoint of film processing, film breakage tends to occur during thin film processing, resulting in a marked decrease in productivity.

Patent Document 1 describes a capacitor film composed of 100 parts by weight of polypropylene and 5 to 100 parts by weight of one or more resins selected from petroleum resins and terpene resins substantially free of double bonds and polar groups. discloses a capacitor film which is excellent in biaxial stretchability and whose dielectric breakdown voltage does not decrease even when the film is thinned.

In Patent Document 2, it consists of 100 parts by weight of polypropylene and 5 to 50 parts by weight of a resin selected from petroleum resins and terpene resins that do not substantially contain double bonds and polar groups, and has a specified surface roughness. A capacitor film having excellent dielectric breakdown strength and little change in capacitance over time and having high security is disclosed.

Patent Document 3 discloses a biaxial biaxial polymer comprising polypropylene containing long chain branches and 0.1 to 30% by weight of a stretching aid selected from petroleum resins and terpene resins substantially free of double bonds and polar groups. Disclosed is a capacitor film excellent in dielectric breakdown strength by controlling the stereoregularity and ash content of polypropylene within a specific range in a stretched film.

JP-A-61-218125 JP-A-11-162779 JP-A-2004-161799

However, the techniques described in Patent Documents 1 to 3 have a technical problem that the dielectric breakdown strength at high temperatures (especially 100° C. or higher) is low and the capacitor cannot be used at high temperatures. In addition, when the capacitor film is used at high temperatures, the petroleum resin bleeds out on the film surface, which reduces the adhesion of metal vapor deposition films such as aluminum and zinc, and may impair the performance of the film capacitor. For these reasons, there is a demand for the development of a capacitor film that has excellent high-temperature withstand voltage properties and excellent thin-film stretchability.

The present invention provides a capacitor film which is excellent in high-temperature withstand voltage and thin film stretchability and is free from the risk of deterioration in performance due to a decrease in adhesion of a metal vapor deposition film, and a polypropylene-based resin composition capable of producing the capacitor film. intended to provide

The present inventors have diligently studied to solve the above problems. As a result, it was found that the above problems could be solved by a polypropylene resin composition obtained by blending a specific amount of hydrogenated petroleum resin with a specific propylene homopolymer, and a film comprising a resin layer containing the composition. I have perfected my invention. Examples of aspects of the invention are provided below.

[1] Hydrogenated petroleum resin (B) having the following properties (B-1) is added to 100 parts by mass of a propylene homopolymer (A) having the following properties (A-1) to (A-4). A polypropylene-based resin composition for a capacitor film containing 1 to 2.0 parts by mass:
(A-1) Melt flow rate (ASTM D1238, 230° C., 2.16 kg load) is 1.0 to 10.0 g/10 minutes;
(A-2) the mesopentad fraction (mmmm) is 0.940 or more;
(A-3) the molecular weight distribution (Mw/Mn) measured by GPC is 3.0 or more;
(A-4) the chlorine content is 3 ppm by mass or less;
(B-1) The softening temperature is 100 to 160°C.
[2] The polypropylene resin composition for a capacitor film according to item [1], wherein the hydrogenated petroleum resin (B) is an alicyclic hydrocarbon resin.
[3] A capacitor film comprising a resin layer containing the polypropylene-based resin composition described in item [1] or [2].
[4] The capacitor film according to item [3], which has a thickness of 1 to 50 μm.
[5] The capacitor film according to item [3] or [4], which is drawn at a stretched area ratio (longitudinal×horizontal area ratio) of 30 to 80 times.

ADVANTAGE OF THE INVENTION According to the present invention, there is provided a capacitor film which is excellent in high-temperature withstand voltage property and thin film stretchability, and which is free from the risk of deterioration in performance due to a decrease in adhesive strength of a metal deposition film, and a polypropylene-based resin composition from which the capacitor film can be produced. can be provided.

The polypropylene-based resin composition for a capacitor film of the present invention (hereinafter also simply referred to as "the composition of the present invention") is a propylene homopolymer (A) having the following properties (A-1) to (A-4): It is characterized by containing 0.1 to 2.0 parts by mass of a hydrogenated petroleum resin (B) having the following properties (B-1) in 100 parts by mass.
(A-1) Melt flow rate (ASTM D1238, 230° C., 2.16 kg load) is 1.0 to 10.0 g/10 minutes.
(A-2) The mesopentad fraction (mmmm) is 0.940 or more.
(A-3) The molecular weight distribution (Mw/Mn) measured by GPC is 3.0 or more.
(A-4) The chlorine content is 3 mass ppm or less.
(B-1) The softening temperature is 100 to 160°C.

A stretched film obtained from a polypropylene-based resin composition that satisfies the above requirements is suitable as a capacitor film because it is excellent in high-temperature voltage resistance and thin film stretchability, and there is no risk of performance deterioration due to a decrease in the adhesive strength of the metal vapor deposition film. That is, the capacitor film of the present invention is characterized by including a resin layer containing the composition of the present invention.

[Polypropylene resin composition]
The composition of the present invention is characterized by containing 0.1 to 2.0 parts by mass of hydrogenated petroleum resin (B) based on 100 parts by mass of propylene homopolymer (A). The blending amount of the hydrogenated petroleum resin (B) is preferably 0.2 to 1.5 parts by mass, more preferably 0.3 to 1.0 parts by mass with respect to 100 parts by mass of the polypropylene resin (A). be. When the amount of component (B) is within the above range, the high-temperature withstand voltage of the capacitor film is remarkably improved. If the amount is less than 0.1 part by mass, the effect on high-temperature withstand voltage is small, and if it exceeds 2.0 parts by mass, the effect on high-temperature withstand voltage is reduced, and depending on the usage environment of the capacitor, metal deposition may occur. There is a risk of deterioration in performance due to a decrease in film adhesion.

Patent Documents 1 to 3 do not contain any description suggesting the above effect, and the reason for this is not necessarily clear from the documents, but the present inventors consider as follows.
Technical literature on dielectric breakdown voltage "Takayuki Yamakita, Tomio Ariyasu, Journal of the Institute of Electrical Engineers of Japan A, Vol. It is known that the dielectric breakdown voltage of crystals is higher than that of amorphous crystals. The reason why amorphous has a low dielectric breakdown voltage is interpreted to be that amorphous has a lower density than crystal and has many voids, which are defects, so that it is easy to discharge. Here, when the hydrogenated petroleum resin (B) is blended in the range of 0.1 to 2.0 parts by mass with respect to 100 parts by mass of the propylene homopolymer (A), the hydrogenated petroleum resin (B) is Since it exists selectively in the amorphous of the propylene homopolymer (A), only amorphous voids are reduced without reducing the crystallinity of the propylene homopolymer (A), so that the dielectric breakdown voltage is high. It is thought that When the blending amount of the hydrogenated petroleum resin (B) exceeds 2.0 parts by mass, the hydrogenated petroleum resin (B) enters not only the amorphous propylene homopolymer (A) but also the crystals, resulting in crystallization. It is thought that the dielectric breakdown voltage decreased due to the decrease in the temperature.

[Propylene homopolymer (A)]
The propylene homopolymer (A) used in the present invention has properties (A-1) to (A-4) described below. Here, since the propylene homopolymer has higher crystallinity and melting point than the propylene copolymer, it is excellent in dielectric breakdown resistance at high temperature. In addition, the propylene homopolymer (A) may have long chain branches within a range that does not hinder the object of the present invention. A propylene homopolymer having no

<Characteristics (A-1)>
The melt flow rate (MFR, ASTM D1238, 230° C., 2.16 kg load) of the propylene homopolymer (A) is 1.0 to 10.0 g/10 minutes, preferably 1.2 to 8.0 g/10 minutes. minutes, more preferably 1.5 to 6.0 g/10 minutes. When the MFR is less than 1.0 g/10 minutes, it is difficult to form a raw film with an extruder, and the chuck may come off during stretching, making it impossible to obtain a desired stretched film. On the other hand, when the MFR exceeds 10.0 g/10 minutes, the productivity of the film tends to decrease, such as frequent film breakage during stretching. The MFR can be set within the above range by adjusting the hydrogenation amount during the polymerization of the propylene homopolymer (A) or by blending propylene homopolymers (A) with different MFRs. .

<Characteristics (A-2)>
The mesopentad fraction (mmmm) of the propylene homopolymer (A) measured by ¹³ C-NMR (nuclear magnetic resonance) is 0.940 or more, preferably 0.950 or more, and more preferably 0.960 or more. . If the mesopentad fraction (mmmm) is less than 0.940, the high-temperature withstand voltage of the film may deteriorate.

<Characteristics (A-3)>
The molecular weight distribution (Mw/Mn, the value obtained by dividing the weight average molecular weight Mw by the number average molecular weight Mn) of the propylene homopolymer (A) measured by gel permeation chromatography (GPC) is 3.0 or more, preferably 4. 0 or more and 14.0 or less, more preferably 5.0 or more and 12.0 or less, and particularly preferably 6.0 or more and 11.0 or less. If the molecular weight distribution (Mw/Mn) is less than 4.0, the stretchability of the thin film may deteriorate, and a film with good thickness accuracy may not be obtained. Stress may increase and thermal shrinkage may increase.

<Characteristics (A-4)>
The chlorine content of the propylene homopolymer (A) is 3 mass ppm or less, preferably 2 mass ppm or less, more preferably 1.5 mass ppm or less. When the chlorine content exceeds 3 ppm by mass, not only the voltage resistance of the resulting stretched film is lowered, but also the long-term capacitor properties are lowered. It is believed that when a capacitor is used, the electric field in the vicinity of chloride ions inside the film increases locally, and dielectric breakdown tends to occur from there, resulting in a decrease in withstand voltage. The chlorine content can be controlled within the above range by post-treating a propylene homopolymer or by blending a propylene polymer obtained with a metallocene catalyst.

<Method for Producing Propylene Homopolymer (A)>
The method for producing the propylene homopolymer (A) is not particularly limited. For example, it can be produced using a Ziegler-Natta catalyst, which is a combination of a titanium compound and an organoaluminum compound, or a metallocene catalyst. In the present invention, a polypropylene resin having a relatively wide molecular weight distribution is preferred, so production using a Ziegler-Natta catalyst is generally more preferred.

Ziegler-Natta catalysts include, for example, titanium trichloride or titanium tetrachloride supported on a carrier such as magnesium halide, and organoaluminum compounds. In particular, it is preferable to use a catalyst that is highly active and originally contains little titanium component.

The propylene homopolymer (A) can be produced by bulk polymerization, liquid phase polymerization such as solution polymerization or suspension polymerization, or gas phase polymerization. Among these, liquid phase polymerization such as bulk polymerization and suspension polymerization and gas phase polymerization are preferred.

When the propylene homopolymer (A) yields a small amount of polymer per unit amount of catalyst, it is necessary to perform a post-treatment to remove the catalyst residue. In addition, even when a large amount of polymer is produced due to the high activity of the catalyst, it is preferable to remove the catalyst residue by post-treatment. Examples of the post-treatment method include a method of washing the propylene homopolymer obtained by polymerization with liquid propylene, butane, hexane, heptane, or the like. At this time, water, an alcohol compound, a ketone compound, an ether compound, an ester compound, an amine compound, an organic acid compound, an inorganic acid compound, or the like may be added to solubilize the catalyst components such as titanium and magnesium to facilitate extraction. good. It is also preferred to wash with a polar compound such as water or alcohol.

Furthermore, the propylene homopolymer obtained by the above polymerization is preferably subjected to dehalogenation treatment, and dehalogenation treatment using an epoxy compound is particularly preferable. As the epoxy compound, for example, an alkylene oxide such as ethylene oxide, propylene oxide, butene oxide or cyclohexene oxide, glycidyl alcohol, glycidyl acid or glycidyl ester is preferably used. When dechlorinating a propylene homopolymer using these epoxy compounds, it is very effective to use a compound having an OH group equal to or greater than that of the epoxy compound. Here, the compound having an OH group includes water or an alcohol compound.

[Hydrogenated petroleum resin (B)]
The hydrogenated petroleum resin (B) used in the present invention has properties (B-1) described later. In addition, the hydrogenated petroleum resin (B) usually consists of C5 and C9 fractions among the remaining fractions obtained by pyrolyzing petroleum naphtha using aluminum chloride as a polymerization catalyst and extracting necessary fractions. They are produced by polymerizing unsaturated hydrocarbons and include hydrogenated derivatives of aliphatic hydrocarbon resins, alicyclic hydrocarbon resins and aromatic hydrocarbon resins. From the viewpoint of dielectric breakdown strength at high temperatures and colorless and odorless, more preferably a resin having a hydrogenation rate of 95% by mass or more, more preferably a derivative such as a hydrogenated rosin, a hydrogenated terpene resin, or a hydrogenated petroleum resin. be. Alicyclic hydrocarbon resins are particularly preferred because of their high compatibility with polypropylene.

<Characteristics (B-1)>
The softening temperature of the hydrogenated petroleum resin (B) is 100-160°C. It is preferably 110 to 155°C, more preferably 130 to 150°C. If the softening temperature is less than 100°C, the dielectric breakdown strength at high temperatures tends to decrease, and if it exceeds 160°C, voids are generated during film stretching, and the dielectric breakdown strength is reduced not only at high temperatures but also at room temperature. tend to decline. The softening temperature can be measured by a method conforming to JIS K2207.

Commercially available products of hydrogenated petroleum resin (B) include, for example, Idemitsu Kosan Co., Ltd. "Imarb", Arakawa Chemical Industries, Ltd. "Alcon", Exxon Mobil Co., Ltd. "Oppera", JXTG Energy Co., Ltd. "T-REZ" manufactured by the company and the like can be mentioned.

[Method for preparing polypropylene resin composition]
As a method for preparing the composition of the present invention, the powdery or pelletized propylene homopolymer (A), the hydrogenated petroleum resin (B), and, if necessary, other additives are dry-blended, Henschel A method of mixing with a mixer or the like can be mentioned. Alternatively, these raw materials may be melt-kneaded in advance using a single-screw or twin-screw kneader, a kneader, or the like.

Other additives include, for example, antioxidants and neutralizing agents. The blending amount of the antioxidant is preferably 500 mass ppm or more and 8000 mass ppm or less, more preferably 750 mass ppm or more and 7500 mass ppm or less, relative to the propylene homopolymer (A). In addition, the amount of the neutralizing agent is preferably 5 mass ppm or more and 1000 mass ppm or less, more preferably 10 mass ppm or more and 750 mass ppm or less, and still more preferably 15 mass ppm with respect to the propylene homopolymer (A). It is more than 500 mass ppm or less.

Additives other than antioxidants and neutralizers can also be used as long as they are known additives that can be blended with polypropylene resin, as long as they do not impair the object of the present invention. Such additives include, for example, nucleating agents (α crystal nucleating agents such as phosphate ester metal salts and sorbitol compounds, and β crystal nucleating agents such as amide compounds), ultraviolet absorbers, lubricants, flame retardants, electrifying agents, and an inhibitor.

In the preparation of the composition of the present invention, since the content of the hydrogenated petroleum resin (B) is small, a masterbatch consisting of a high-concentration hydrogenated petroleum resin (B) and a polypropylene resin is prepared in advance. It is preferable to blend the batch and the propylene homopolymer (A) so that the blending ratio is within a predetermined range. The polypropylene resin, which is the raw material of the masterbatch, may be the propylene homopolymer (A) or another polypropylene resin, but it is more preferable to use the propylene homopolymer (A).

<Manufacturing method of capacitor film>
The capacitor film of the invention can be produced, for example, by producing a raw sheet using the composition of the invention and then stretching the same.

The raw sheet can be manufactured, for example, as follows. First, the polypropylene resin composition is supplied from a hopper to an extruder, heated and melted at preferably 170 to 300° C., more preferably 200 to 260° C., and melt-extruded through a T-die. Next, by cooling and solidifying the extruded melt with a metal chill roll at 70 to 120° C., an unstretched original sheet is obtained. Although the thickness of the original sheet is not particularly limited, it is preferably 60 to 800 μm, more preferably 80 to 400 μm. If the original sheet has a thickness of less than 60 μm, it may break during stretching. On the other hand, if the thickness exceeds 800 μm, it may not be suitable as a capacitor film because a thin film cannot be obtained.

In the method for producing a capacitor film of the present invention, it is preferable to stretch the raw sheet obtained as described above. The stretching method includes a uniaxial stretching method and a biaxial stretching method, and the biaxial stretching method is preferable. The biaxial stretching method includes a sequential biaxial stretching method in which the film is uniaxially stretched in the machine direction and then in a direction perpendicular to the machine direction; An axial stretching method and the like can be mentioned. Specifically, a tenter method, a sequential biaxial stretching method such as a tubular film method, and a simultaneous biaxial stretching method can be used.

The tenter method can be performed, for example, by the following method. The molten sheet melted and extruded from the T-die is solidified by cooling rolls, preheated if necessary, and then introduced into the stretching zone. Next, the sheet is stretched 3 to 9 times in the machine direction (longitudinal direction) at a temperature of 120 to 160° C., and then stretched in the direction perpendicular to the machine direction (transverse direction) at a temperature of 150 to 190° C. by 5 to 11 times. do. The total stretched area ratio (longitudinal×horizontal area ratio) is preferably 30 to 80 times, more preferably 35 to 75 times, even more preferably 35 to 70 times, and particularly preferably 40 to 50 times. If the stretched areal ratio is less than 30 times, it may be difficult to obtain the desired strength and thickness accuracy. On the other hand, if the stretching areal ratio exceeds 80 times, the film tends to break during stretching, which may lead to poor productivity.

In the present invention, the film biaxially stretched as described above can be heat-set at 160 to 190° C., if necessary. This makes it possible to obtain a stretched film with improved thermal dimensional stability and abrasion resistance.

<Condenser film>
The stretched film obtained as described above includes a resin layer containing a propylene homopolymer (A) and a specific amount of hydrogenated petroleum resin (B), and is excellent in high-temperature voltage resistance and thin film stretchability. It is suitable as a capacitor film that does not have a risk of deterioration in performance due to a decrease in adhesiveness of the metal deposition film. The capacitor film of the present invention may be a single-layer film having one resin layer, or a laminated film having two or more resin layers.

The thickness of the capacitor film of the present invention is preferably 1-50 μm, more preferably 1.5-30 μm, even more preferably 1.5-20 μm, and particularly preferably 2-15 μm. When the thickness is within the above range, film breakage is less likely to occur, the productivity of the film is improved, and the film is lightweight and excellent in flexibility.

By forming a metal layer of aluminum, zinc or the like on the capacitor film of the present invention by a vacuum deposition method or the like, it can be suitably used as a capacitor.

EXAMPLES The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples. The methods for measuring physical properties and the resins used in Examples and Comparative Examples are as follows.

1. Physical property measurement method (1) Melt flow rate (MFR)
Melt flow rate (MFR) was measured under conditions of 230° C. and 2.16 kg load according to ASTM D1238.

(2) mesopentad fraction (mmmm)
The mesopentad fraction (mmmm) of the propylene homopolymer is determined according to A.I. It is a value defined by the assignment shown in Zambelli et al., Macromolecules, 8, 687 (1975), and was measured by ¹³ C-NMR under the following conditions. The mesopentad fraction is a value represented by the following formula.
Mesopentad fraction = (peak area at 21.7 ppm)/(peak area at 19-23 ppm)
<Measurement conditions>
Apparatus: JNM-Lambda400 (trade name, manufactured by JEOL Ltd.)
Resolution: 400MHz
Measurement temperature: 125°C
Solvent: 1,2,4-trichlorobenzene/deuterated benzene = 7/4 (mass ratio)
Pulse width: 7.8 μsec
Pulse interval: 5 sec
Accumulated times: 2000 times Shift standard: TMS = 0 ppm
Mode: Single pulse broadband decoupling

(3) molecular weight distribution (Mw/Mn)
The Mw/Mn of the propylene homopolymer was calculated by measuring under the following conditions and analyzing the obtained chromatogram. Calculation of the molecular weight was performed by the universal calibration method, and the value converted to polystyrene was calculated. The baseline of the GPC chromatogram was set from the starting point of the retention time at which the elution curve rises, to the end point of the retention time corresponding to a molecular weight of 1,000.
<Measurement conditions>
Liquid chromatograph: ALC/GPC 150-C Plus type (trade name, integrated differential refractometer detector, manufactured by Waters)
Column: GMH6-HT (trade name, manufactured by Tosoh Corporation) x 2 and GMH6-HTL (trade name, manufactured by Tosoh Corporation) x 2 are connected in series Mobile phase medium: o-dichlorobenzene Flow rate: 1. 0 mL/min Measurement temperature: 140°C
Sample concentration: 0.10% (W/W)
Sample solution volume: 500 μL

(4) Chlorine Content 0.8 g of the sample was burned at 400 to 900° C. under an argon/oxygen stream using a Mitsubishi Kasei combustion apparatus. After that, the combustion gas was captured with ultrapure water, and the sample solution after concentration was treated with a DIONEX-DX300 type ion chromatography device (trade name, manufactured by Nippon Dioneck Co., Ltd.) and an anion column AS4A-SC (trade name, Dionek Co., Ltd.). ) was used to determine the chlorine content.

(5) Dielectric strength (BDV)
The BDV of the obtained stretched film was measured according to JIS-C2330. The dielectric breakdown voltage of the biaxially stretched film was measured at 120°C. The withstand voltage (BDV, V/μm) was calculated by dividing the dielectric breakdown voltage by the film thickness.

(6) Thin Film Stretchability Immediately after biaxially stretching the film, interference fringes related to smoothness were visually observed and evaluated according to the following criteria.
x: The smoothness of the film is low because interference fringes were observed.
◯: No interference fringes were observed, and there was no problem with the smoothness of the film.
⊚: No interference fringes were observed, the smoothness of the film was satisfactory, and the stretching temperature range was wide.

(7) Adhesive Force of Vapor-deposited Metal Film A capacitor film was prepared by subjecting the film surface to corona treatment and then vapor-depositing aluminum at a degree of vacuum of 2×10 ⁻⁴ Torr for a vapor deposition time of 20 seconds. The vapor-deposited film side of this metal vapor-deposited film and the PE film "HM-52" (trade name, manufactured by Tamapoly Co., Ltd., grade: ionomer, thickness: 30 μm) were sealed at a temperature of 120° C., a sealing pressure of 2.0 kg/cm ² , and a sealing time. A 10 mm x 15 mm wide seal was performed for 1.0 second, and the T-peel strength was measured at a tensile speed of 300 m/min to evaluate the vapor deposition strength (N/15 mm) of the vapor deposition film.

2. Materials used (1) Propylene homopolymer (A)
A1: Propylene homopolymer (MFR: 2.0 g/10 min, Mw/Mn: 9.6, mmmm: 0.974, chlorine content: 1 ppm)

<Production Example of Propylene Homopolymer (A1)>
[Production Example 1]
(i) Production of Solid Catalyst A 2-liter high-speed stirring device (“TK Homomixer M” manufactured by Tokushu Kika Kogyo Co., Ltd.) was sufficiently purged with nitrogen. 2 g and 3 g of sorbitan distearate (“Rheodol SP-S20” manufactured by Kao Corporation) were added, and the temperature of the reaction system was raised while stirring the suspension, and the suspension was stirred at 120° C. for 30 minutes at 800 rpm. Stirred. Next, 1 liter of purified decane previously cooled to −10° C. was added to this suspension using a Teflon (registered trademark) tube with an inner diameter of 5 mm while stirring at high speed so as not to generate precipitates. Transferred to a 2 liter glass flask with stirrer. The solid produced by the liquid transfer was filtered and thoroughly washed with purified n-heptane to obtain a solid adduct in which 2.8 mol of ethanol was coordinated with 1 mol of magnesium chloride.

This solid adduct was suspended in decane, and 23 mmol of the solid adduct in terms of magnesium atom was introduced into 100 ml of titanium tetrachloride maintained at -20°C with stirring to form a mixed solution. got The mixture was heated to 80° C. over 5 hours, and when the temperature reached 80° C., diisobutyl 3,6-dimethylcyclohexane-1,2-dicarboxylate (mixture of cis and trans isomers) was added to the solid adduct. was added in an amount of 0.085 mol with respect to 1 mol of magnesium atom of , and the temperature was raised to 110° C. in 40 minutes. When the temperature reached 110°C, diisobutyl cyclohexane 1,2-dicarboxylate (mixture of cis and trans isomers) was further added in an amount of 0.0625 mol per mol of magnesium atom in the solid adduct, and the temperature These were reacted by holding at 110° C. for 90 minutes with stirring.

After completion of the reaction for 90 minutes, the solid portion was collected by hot filtration, resuspended in 100 ml of titanium tetrachloride, and stirred for 45 minutes when the temperature was raised to 110°C. These were reacted by holding while holding. After completion of the reaction for 45 minutes, the solid portion was collected again by hot filtration and thoroughly washed with decane and heptane at 100° C. until free titanium compounds were no longer detected in the washing liquid.

The solid titanium catalyst component (α-1) prepared by the above procedure was stored as a decane suspension, and part of it was dried for the purpose of examining the catalyst composition.
The composition of the solid titanium catalyst component (α-1) thus obtained was 3.2% by mass of titanium, 17% by mass of magnesium, 57% by mass of chlorine, and diisobutyl 3,6-dimethylcyclohexane-1,2-dicarboxylate. 10.6% by weight, 8.9% by weight of diisobutyl cyclohexane 1,2-dicarboxylate, and 0.6% by weight of ethyl alcohol residues.

(ii) Preparation of prepolymerization catalyst 150 g of the solid catalyst component prepared in (i) above, 74.4 mL of triethylaluminum, and 75 L of heptane are placed in a 200 L autoclave equipped with a stirrer and maintained at an internal temperature of 10 to 18°C. was added and reacted with stirring for 60 minutes. This prepolymerization catalyst contained 6 grams of polypropylene per gram of transition metal catalyst component.

(iii) Main Polymerization Into a 1000 L vessel polymerization vessel equipped with a stirrer, 132 kg/hour of propylene, 1.4 g/hour of the above catalyst slurry as a transition metal catalyst component, 8.4 mL/hour of triethylaluminum, and dicyclopentyldimethoxysilane were charged. 16.2 mL/hour was continuously supplied, and hydrogen was supplied so that the hydrogen concentration in the gas phase was 2.5 mol %. Polymerization was carried out at a polymerization temperature of 74°C and a pressure of 3.2 MPa/G.

The obtained slurry was sent to a vessel polymerization vessel with an internal volume of 500 L and equipped with a stirrer, and was further polymerized. To the polymerization reactor, 29 kg/hour of propylene and hydrogen were supplied so that the hydrogen concentration in the gas phase was 1.8 mol %. Polymerization was carried out at a polymerization temperature of 71°C and a pressure of 3.1 MPa/G.

The resulting slurry was sent to another 500-L vessel polymerization vessel equipped with a stirrer to carry out further polymerization. To the polymerization reactor, 23 kg/hour of propylene and hydrogen were supplied so that the hydrogen concentration in the gas phase was 1.5 mol %. Polymerization was carried out at a polymerization temperature of 69°C and a pressure of 3.1 MPa/G.

After deactivation, the obtained slurry was sent to a washing tank with liquid propylene to wash the polypropylene powder.
After vaporizing the obtained slurry, gas-solid separation was carried out to obtain a propylene polymer. The obtained propylene polymer was introduced into a conical dryer and vacuum-dried at 80°C. Then, 60 grams of pure water and 0.54 liters of propylene oxide were added to 100 kg of the product, and dechlorination was performed at 90° C. for 2 hours, followed by vacuum drying at 80° C. to obtain polypropylene powder. rice field. The chlorine content of the obtained propylene homopolymer (A1) was 1 ppm.

Next, 0.2 parts by mass of 3,5-di-tert-butyl-4-hydroxytoluene as an antioxidant and tetrakis[methylene-3 0.2 parts by mass of (3,5-di-tert-butyl-4-hydroxyphenyl)propionate]methane and 0.01 parts by mass of calcium stearate as a neutralizing agent were mixed and dry-blended. Thereafter, using a twin-screw extruder "TEM-35" manufactured by Toshiba Machine Co., Ltd., granulation was performed at a cylinder temperature of 210 ° C., a screw rotation speed of 150 rpm, and an extrusion rate of 15 kg / h while sealing the hopper with nitrogen. A coalescent (A1) pellet was obtained. As a result of measuring physical properties using the obtained pellets, MFR=2.0, mmmm=0.974, and Mw/Mn=9.6.

(2) Hydrogenated petroleum resin (B)
・ B1: Hydrogenated alicyclic hydrocarbon resin "OPPERA, PR100N" manufactured by Exxon Mobil (softening temperature: 140 ° C.)
・ B2: Hydrogenated alicyclic hydrocarbon resin manufactured by Idemitsu Kosan Co., Ltd. “Imarb P-140” (softening temperature: 140 ° C.)
・ B3: Hydrogenated alicyclic hydrocarbon resin “Arcon P-140” manufactured by Arakawa Chemical Co., Ltd. (softening temperature: 140 ° C., hydrogenation rate of aromatic ring 95%)
・ B4: Hydrogenated alicyclic hydrocarbon resin “T-REZ OP501” manufactured by Tonen Chemical LLC (softening temperature: 140 ° C)
・ B5: Hydrogenated alicyclic hydrocarbon resin “T-REZ HA125” manufactured by Tonen Chemical LLC (softening temperature: 125 ° C.)

3. Examples and Comparative Examples [Examples 1 to 14]
(1) Preparation of Polypropylene Resin Compositions Master batches (C1 to C5) were prepared by previously blending 100 parts by mass of propylene homopolymer (A1) and 20 parts by mass of hydrogenated petroleum resins (B1 to B5). Next, the propylene homopolymer (A1) and the masterbatch were blended so as to have the composition shown in Table 1. After that, using a twin-screw extruder "TEM-35" manufactured by Toshiba Machine Co., Ltd., granulating at a cylinder temperature of 210 ° C., a screw rotation speed of 150 rpm, and an extrusion rate of 15 kg / h while sealing the hopper with nitrogen, to obtain a polypropylene resin. A composition was obtained.

(2) Molding of original sheet The pellets of the obtained polypropylene-based resin composition were melted and extruded at 230 ° C. with a 25 mmφ T-die sheet molding machine (manufactured by Plastic Engineering Laboratory Co., Ltd.), and held at 65 ° C. It was cooled at a drawing speed of 1.0 m/min with one cooling roll to obtain a raw sheet with a thickness of 350 μm.

(3) Production of Stretched Film The obtained raw sheet was cut into 85 mm×85 mm and biaxially stretched under the following conditions to obtain a 6 μm thick biaxially stretched film. The thickness was adjusted by changing the preheating temperature. Evaluation was performed using the obtained stretched film. Table 1 shows the results.

<Stretching conditions>
Stretching device: KAROIV (trade name, manufactured by Bruckner)
Preheating temperature: 145-160°C
Preheating time: 60 seconds Stretch ratio: sequential biaxial stretching of 5 times in the longitudinal direction (machine direction) x 9 times in the transverse direction (stretching ratio: 45 times)
Stretching speed: 6m/min

[Comparative Example 1]
A stretched film was produced and evaluated in the same manner as in Example 1, except that the pellets of the propylene homopolymer (A1) were used as the starting material. Table 2 shows the results.

[Comparative Examples 2 to 5]
A stretched film was produced in the same manner as in Example 1, except that the propylene homopolymer (A1) and the masterbatch (C1) were blended so as to have the composition shown in Table 2 to prepare a polypropylene-based resin composition. and evaluated. Table 2 shows the results.

[Comparative Examples 6 to 8]
A stretched film was produced and evaluated in the same manner as in Example 1, except that the masterbatch (C1 to C3) produced in Example 1 was used as a raw material. Table 2 shows the results.

As is clear from Table 1 above, the films of Examples 1 to 14 of the present invention have high dielectric breakdown voltages at high temperatures and high adhesion to the metal deposition film. On the other hand, as is clear from Table 2 above, the films of Comparative Examples 1 to 8 do not satisfy the requirements of the present invention, and therefore do not exhibit the intended performance.

Claims (5)

0.1 to 2 hydrogenated petroleum resin (B) having the following properties (B-1) per 100 parts by mass of the propylene homopolymer (A) having the following properties (A-1) to (A-4) A polypropylene-based resin composition for a capacitor film containing 0 parts by mass:
(A-1) Melt flow rate (ASTM D1238, 230° C., 2.16 kg load) is 1.0 to 10.0 g/10 minutes;
(A-2) the mesopentad fraction (mmmm) is 0.940 or more;
(A-3) the molecular weight distribution (Mw/Mn) measured by GPC is 3.0 or more;
(A-4) the chlorine content is 3 ppm by mass or less;
(B-1) The softening temperature is 100 to 160°C. 2. The polypropylene resin composition for a capacitor film according to claim 1, wherein the hydrogenated petroleum resin (B) is an alicyclic hydrocarbon resin. A capacitor film comprising a resin layer containing the polypropylene-based resin composition according to claim 1 . 4. The capacitor film according to claim 3, wherein the thickness is 1-50 μm. 5. The capacitor film according to claim 3, wherein the film is stretched at a stretched area ratio (longitudinal×horizontal area ratio) of 30 to 80 times.