Capacitor composition containing nucleated polypropylene and cyclic olefin polymer

Abstract

The present invention relates to a polypropylene composition comprising a high-isotactic homopolymer of propylene in a content of 70 to less than 95% by mass, a cyclic olefin polymer composition in a content of 5 to less than 30% by mass, and a nucleating agent in a content of 0.0000001 to 1% by mass. The present invention further relates to a cast film comprising the polypropylene composition and a biaxially oriented film comprising the polypropylene composition. The present invention also provides a capacitor comprising the biaxially oriented film.

Description

[Technical Field]

[0001] The present invention relates to a polypropylene composition comprising a high-isotactic homopolymer of propylene in a content of 70 to less than 95% by mass, a cyclic olefin polymer composition in a content of 5 to less than 30% by mass, and a nucleating agent in a content of 0.0000001 to 1% by mass. The present invention further relates to a cast film comprising the polypropylene composition and a biaxially oriented film comprising the polypropylene composition. The present invention also provides a capacitor comprising the biaxially oriented film. [Background technology]

[0002] Polypropylene has a relatively high dielectric constant, low dielectric loss tangent, and good dielectric strength. For these reasons, polypropylene has been advantageously used as a dielectric in various capacitor film applications. However, known polypropylene capacitor grades have limitations in their maximum operating temperature and susceptibility to oxidation. New generations of inverters, such as traction inverters for electric mobility and inverters for renewable power sources like solar and wind, require capacitor films that can operate at higher temperatures and have greater oxidation resistance. The demand for greater stability against external influences such as high temperatures or oxygen-enriched atmospheres has been addressed through various methods. Patent Document 1 proposes combining polypropylene with composite rubber powder in a mass ratio of 100:0.01 to 2.0. The particle size of the composite rubber powder is 20 to 100 nm and consists of silicone rubber powder and a nucleating agent in a mass ratio of 99:1 to 90:10. This is prepared by mixing silicone rubber latex obtained by irradiation vulcanization with an aqueous solution or emulsion of the nucleating agent. Patent Document 2 teaches that when the beta nucleation of high-purity polypropylene is combined with long-chain branched polypropylene, high-temperature resistance can be achieved. More specifically, the present invention provides a polypropylene composition comprising a propylene homopolymer of 95.0 to 99.9% by mass, having a specific melt flow rate and an extremely low ash content, 0.1 to 5.0% by mass of long-chain branched polypropylene, and up to 1000 ppm of a beta nucleating agent. Patent Documents 3 and 4 suggest that in order to obtain a material suitable for high-temperature capacitor applications, it may be preferable to blend polypropylene with a specific amount of a specific cyclic olefin copolymer. In this regard, Patent Document 3 depends on an ethylene norbornene copolymer having a specific norbornene content, while Patent Document 4 suggests a cyclic olefin polymer having a glass transition temperature of 120 to 170°C. However, in the above approach, in order to enhance the temperature resistance of the capacitor polypropylene composition, other important properties have to be sacrificed. For example, mechanical properties such as low shrinkage and high rigidity, as well as the resistance performance to high voltage, are sacrificed to some extent.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0004] Therefore, there is still a need to provide a polypropylene composition with an improved set of characteristics for capacitor applications, namely high temperature resistance, high oxidation resistance, high electrical breakdown strength, and suitable mechanical properties. Accordingly, an object of the present invention is to overcome the above problems of known compositions and provide a polypropylene composition that meets these needs. Another object of the present invention is to provide a polypropylene film with excellent performance for capacitor applications. Finally, the present invention aims to improve the specifications of capacitors. Furthermore, the capacitor film must have high dielectric breakdown strength and good mechanical properties such as low shrinkage and high rigidity. [Means for solving the problem]

[0005] The above objectives are achieved by a polypropylene composition having the features of claim 1, a cast film having the features of claim 11, a biaxially oriented film having the features of claim 14, and a capacitor having the features of claim 15. [Modes for carrying out the invention]

[0006] The polypropylene composition according to the present invention comprises (A) a high isotactic homopolymer of propylene in a content of 70 to less than 95% by mass, (B) a cyclic olefin polymer composition in a content of 5 to less than 30% by mass, and (C) a nucleating agent in a content of 0.0000001 to 1% by mass, wherein the content of (A), (B), and (C) is each relative to the total mass of the polypropylene composition. The polypropylene composition may further contain branched propylene polymer. For example, the polypropylene composition comprises (A) a high isotactic homopolymer in a content of 75 to less than 85% by mass, (B) a cyclic olefin polymer composition in a content of 10 to less than 25% by mass, (C) a nucleating agent in a content of 0.0000001 to 1% by mass, and (D) a branched propylene polymer in a content of 0.1 to 10% by mass, where the content of (A) to (D) is relative to the total mass of the polypropylene composition. In other preferred embodiments, the polypropylene composition comprises (A) a high isotactic homopolymer having a content of less than 75-85% by mass, (B) a cyclic olefin polymer composition having a content of less than 10-25% by mass, (C) a nucleating agent having a content of 0.0000001-1% by mass, and (D) comprises a branched propylene polymer in a content of 0.1 to 5% by mass, where the content of (A) to (D) is relative to the total mass of the polypropylene composition. In yet another preferred embodiment, the polypropylene composition comprises (A) a high isotactic homopolymer in a content of 75 to less than 90% by mass, (B) a cyclic olefin polymer composition in a content of 10 to less than 25% by mass, (C) a nucleating agent in a content of 0.0000001 to 1% by mass, and (D) a branched propylene polymer in a content of 0.1 to 5% by mass, where the content of (A) to (D) is relative to the total mass of the polypropylene composition.

[0007] In other, more preferred embodiments, the polypropylene composition comprises (A) a high isotactic homopolymer in a content of less than 78 to 87% by mass, (B) a cyclic olefin polymer composition in a content of less than 13 to 22% by mass, (C) a nucleating agent in a content of 0.0000001 to 1% by mass, and (D) a branched propylene polymer in a content of 0.1 to 5.0% by mass, preferably 0.2 to 2.0% by mass, where the content of (A) to (D) is relative to the total mass of the polypropylene composition, and the glass transition temperature of the cyclic olefin polymer composition is in the range of 130 to 140°C, as measured according to ISO 11357.

[0008] In a particularly preferred embodiment, the polypropylene composition according to the present invention is a polypropylene composition comprising (A) a high isotactic homopolymer of propylene in a content of 70 to less than 82% by mass, (B) a cyclic olefin polymer composition in a content of 18 to less than 30% by mass, and (C) a nucleating agent in a content of 0.0000001 to 1% by mass, wherein the content of (A), (B), and (C) is each relative to the total mass of the polypropylene composition.

[0009] If the polypropylene composition further contains a branched propylene polymer, the polypropylene composition may contain (A) a high isotactic homopolymer of propylene in a content of 75 to less than 82% by mass, (B) a cyclic olefin polymer composition in a content of 18 to less than 25% by mass, (C) a nucleating agent in a content of 0.0000001 to 1% by mass, and (D) a branched propylene polymer in a content of 0.1 to 5% by mass, preferably 0.2 to 2.0% by mass, where the content of (A) to (D) is relative to the total mass of the polypropylene composition. Preferably, the branched propylene polymer is a branched propylene polymer having a branching index g' of 0.9 or less or 0.8 or less, where the branching index g' is [iV] br / [iV] lin It is expressed as the ratio of the above [iV] br The intrinsic viscosity of the branched propylene polymer is [iV] lin This is the intrinsic viscosity of a linear propylene polymer having the same mass-average molecular weight as the branched propylene polymer, and the intrinsic viscosity is measured in decalin at 135°C according to DIN ISO 1628 / 1, October 1999.

[0010] In preferred embodiments, the polypropylene composition is obtained by melt-blending components (A) to (C) and, if present, component (D). Apparatus for melt-blending may be selected from the group consisting of kneaders, mills, and extruders. Furthermore, the cyclic olefin polymer composition itself can be obtained by melt-blending at least two different cyclic olefin polymers. In contrast to the dry blending method, the melt blending method can produce polypropylene compositions with high uniformity.

[0011] When the content of the cyclic olefin polymer composition is selected to be between 5% and less than 30% by mass, the cyclic olefin polymer composition is finely and uniformly dispersed in the matrix of the high-isotactic homopolymer of propylene. In general, the dispersion state of the cyclic olefin polymer composition is considered to affect the mechanical and electrical properties of the propylene composition. The dimensions and shapes of the domains formed by the cyclic olefin polymer composition in the dispersion can be analyzed using an atomic force microscope (AFM) or other types of microscopes. The content of the cyclic olefin polymer composition can be determined by measuring the xylene-soluble content of the polypropylene composition.

[0012] (A) High isotactic homopolymer of propylene The term "propylene homopolymer" as used in this invention refers to polypropylene consisting substantially, i.e., at least 98.0% by mass, preferably at least 99.0% by mass, and more preferably at least 99.4% by mass, of propylene units. Preferably, as described in the Examples section below, only propylene units are used in the propylene homopolymer. 13 It can be detected by 13C NMR spectroscopy. The highly isotactic homopolymer of propylene is preferably linear polypropylene, i.e., polypropylene without detectable amounts of long-chain or short-chain branching.

[0013] In preferred embodiments of the present invention, a highly isotactic homopolymer of propylene is 13 Pentad isotacticity measured by 13C NMR <mmmm>It is characterized by being considerably high. More specifically, the isotactic pentad fraction of the high isotactic homopolymer of propylene may be 93-99.5%, preferably 95-99.0%, and more preferably 96-98.55%. In certain embodiments, the isotactic pentad fraction of the high isotactic homopolymer of propylene is in the range of 96.0-98.5%, and more preferably 97.0-98.0%.

[0014] Preferably, a higher degree of crystallinity in the material leads to higher isotacticity. Furthermore, a higher isotacticity preferably leads to a decrease in the cold xylene-soluble component (XCS) content. Therefore, in a more preferred embodiment of the present invention, the high isotactic homopolymer of propylene of the present invention is characterized by a considerably low XCS content, i.e., an XCS content of 2.0% by mass or less, more preferably 1.8% by mass or less, and even more preferably 1.6% by mass or less. Accordingly, it is particularly understood that the XCS content of the high isotactic homopolymer of propylene of the present invention is in the range of 0.3 to 2.0% by mass, more preferably 0.3 to 1.8% by mass, and even more preferably 0.4 to 1.6% by mass. The XCS content is understood to indicate that the high isotactic homopolymer of propylene preferably does not contain elastomer polymer components such as ethylene propylene rubber. In other words, the high isotactic homopolymer of propylene does not correspond to heterophase polypropylene, i.e., a system consisting of a polypropylene matrix in which the elastomer phase is dispersed. Such a system is usually characterized by a considerably high cold xylene soluble content.

[0015] Alternatively, the propylene high-isotactic homopolymer of the present invention preferably has a melt flow rate within a specific range. For example, the MFR2 (230°C) of the propylene high-isotactic homopolymer may be 0.4 to 10 g / 10 min, preferably 0.5 to 5 g / 10 min, as measured according to ISO 1133. In a particularly preferred embodiment, the MFR2 (230°C) of the propylene high-isotactic homopolymer may be 2.0 to 4.5 g / 10 min, as measured according to ISO 1133. Here, MFR2 (230°C) refers to the melt flow rate measured at 230°C under a 2.16 kg load.

[0016] Furthermore, the ash content of the high-isotactic homopolymer of propylene is preferably 60 ppm or less, more preferably 30 ppm or less, and even more preferably 20 ppm or less. Preferably, the ash content is in the range of 5 to 30 ppm, and particularly in the range of 10 to 20 ppm. A low ash content contributes to achieving satisfactory dielectric properties such as high dielectric strength and low dielectric loss. The ash content can be measured according to ISO 3451-1 (1997).

[0017] The melting temperature Tm of the high-isotactic homopolymer of propylene may be in the range of 150 to 170°C, preferably 160 to 170°C, as measured according to ISO 11357. The crystallization temperature Tc of the high-isotactic homopolymer of propylene, as measured according to ISO 11357, may be in the range of 110 to 130°C, preferably 110 to 120°C.

[0018] The high-isotactic homopolymer of propylene may contain one or more additives. Preferably, the one or more additives are present in an amount of 0 to 2.0% by mass, more preferably 0.05 to 1.0% by mass, and particularly 0.05 to 0.5% by mass, relative to the mass of the high-isotactic homopolymer of propylene (A). One or more additives may be non-polymeric additives and / or polymeric additives, with non-polymeric additives being preferred. For example, one or more additives may be selected from the group consisting of antioxidants, stabilizers, acid scavengers, nucleating agents, colorants, plasticizers, slip agents, anti-scratch agents, dispersants, processing aids, lubricants, pigments, antistatic agents, etc. Particularly preferred are one or more additives selected from the group consisting of antioxidants, stabilizers, acid scavengers, and combinations thereof. The antioxidant and stabilizer may be selected from the group of hindered phenols, more preferably from the group of hindered phenols that do not contain phosphorus or sulfur. The antioxidants and stabilizers are particularly preferably 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene (trade names Irganox 1330, Anox 330, Ethanox 330 and Kinox-30), pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate) (trade names Irganox 1010, Anox 20, Ethanox 310 TF and Kinox-10), octadecyl 3-(3',5'-di-tert-butyl-4-hydroxyphenyl)propionate (trade names Irganox 1076, Anox PP 18 and Kinox-16), and butylhydroxytoluene (trade names Ionol CP and Vulkanox It is one or more compounds selected from the group consisting of BHT, 1,3,5-tris(3',5'-di-tert-butyl-4'-hydroxybenzyl)-isocyanurate (trade names Irganox 3114, Anox IC-14, Ethanox 314 and Kinox-34), and 3,4-dihydro-2,5,7,8-tetramethyl-2-(4,8,12-trimethyltridecyl)-2H-1-benzopyran-6-ol (trade names Irganox E 210 and α-tocopherol).

[0019] The antioxidants and stabilizers are preferably present in a total mass of 500 to 8000 ppm relative to the total mass of the high-isotactic homopolymer (A) of propylene. More preferably, the antioxidants and stabilizers are present in a total mass of 800 to 7000 ppm, even more preferably 1000 to 6000 ppm, and particularly 1500 to 6000 ppm relative to the total mass of the high-isotactic homopolymer (A) of propylene. Considering the desired applications of the composition in the field of capacitors, the antioxidants and stabilizers are preferably free from phosphorus-containing secondary antioxidants such as tris(2,4-ditert-butylphenyl) phosphite. Although not bound by theory, the latter compounds are thought to increase dissipation in the final capacitor.

[0020] The acid scavenger may be a salt of an organic acid such as stearate. These typically help neutralize acids in the polymer. Examples of such compounds include calcium stearate, zinc stearate, and zinc oxide. The acid scavenger is used in an amount of preferably 20 ppm to 2000 ppm, more preferably 50 ppm to 1000 ppm, and most preferably 60 to 600 ppm, relative to the total mass of the high isotactic homopolymer (A) of propylene. Therefore, one or more additives may be selected from the group consisting of, for example, pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate) (trade names Irganox 1010 Anox 20, Ethanox 310 TF and Kinox-10), butylhydroxytoluene (trade names Ionol CP and Vulkanox BHT), calcium stearate, and combinations thereof.

[0021] (B) Cyclic olefin polymer composition The cyclic olefin polymer composition is preferably a thermoplastic composition. A cyclic olefin polymer composition may contain one cyclic olefin polymer or a blend of at least two different cyclic olefin polymers, or may consist essentially of them. The term "cyclic olefin polymer" is understood to be a polymer containing cyclic olefin units. The cyclic olefin polymer may be a cyclic olefin homopolymer or a cyclic olefin copolymer.

[0022] The term "copolymer" in the present invention refers to a polymer prepared from at least two different monomers. In other words, the term "copolymer" also includes terpolymers and copolymers having four or more different monomer units. Therefore, the cyclic olefin polymer may be a copolymer containing a first monomer unit which is a cyclic olefin unit and at least one second monomer unit different from the first monomer unit, such as an acyclic olefin unit. A cyclic olefin copolymer containing at least a first cyclic olefin unit and a second cyclic olefin unit different from the first cyclic olefin unit is equally encompassed by the term "cyclic olefin polymer". The cyclic olefin polymer can be obtained by either ring-opening polymerization or ring-maintaining polymerization of at least one kind of cyclic olefin monomer. Among these, the cyclic olefin polymer obtained by ring-maintaining polymerization is preferred.

[0023] In a more preferred embodiment, at least one kind of cyclic olefin monomer is selected from the group consisting of cyclopentadiene, tetracyclododecene, norbornene and derivatives of the above compounds. Norbornene and its derivatives are particularly preferred examples of at least one kind of cyclic olefin monomer. Norbornene and its derivatives preferably have the following formula (I):

[0024] [Chemical formula] (where n is 0 or 1, m is 0 or an integer, particularly 0 or 1, R 1 R 2 R 3 R 4 R 5 R 6 Each of these is independently selected from the group consisting of hydrogen, halogen, alkyl, cycloalkyl, aryl group, and alkoxy group. R 7 , R 8 , R 9 , R 10 , R 11 , R 12 , R 13 , R 14 , R 15 , R 16 These are independently selected from the group consisting of hydrogen and alkyl groups, R 17 , R 18 , R 19 , R 20 R is independently selected from the group consisting of hydrogen, halogen, alkyl, cycloalkyl and aryl groups, where R 17 and R 19 Alternatively, it may form a cyclic ring or cyclic system, where the cyclic ring or cyclic system may be saturated or unsaturated. It is a compound represented by [formula]. Further and equally preferred examples of norbornene derivatives are given by the following formula (II):

[0025] [ka] (In the formula, R 21 and R 22 These are independently selected from the group consisting of hydrogen, C5-C7 cycloalkyl groups, C5-C7 aryl groups, and C1-C4 alkyl groups, R 23 and R 24 (These are independently selected from the group consisting of hydrogen and C1-C4 alkyl groups.) It is a compound represented by [formula].

[0026] The acyclic olefin monomer may be an α-olefin. Non-limiting examples of α-olefins are C2-C8 α-olefins, such as α-olefins selected from the group consisting of ethylene, propylene, 1-butene, 2-methyl-1-propene (isobutylene), and 3-methyl-1-butene. Preferred α-olefins are linear C2-C8 α-olefins such as ethylene and propylene. Particularly preferred is ethylene as the α-olefin. In one embodiment, the cyclic olefin polymer composition comprises at least one cyclic olefin copolymer selected from the group consisting of norbornene-ethylene copolymer and tetracyclododecene-ethylene copolymer or a blend of at least two of the cyclic olefin copolymers. In a particularly preferred embodiment, the cyclic olefin polymer composition comprises or essentially consists of one norbornene-ethylene copolymer or a blend of two norbornene-ethylene copolymers with different norbornene content. Furthermore, non-limiting examples of cyclic olefin polymers are those commercially available from Mitsui Chemicals as APEL® or from TOPAS Advanced Polymers as TOPAS®.

[0027] The glass transition temperature (hereinafter also referred to as "Tg") of a cyclic olefin polymer composition may be controlled by the type of monomer used, for example, by at least one type of cyclic olefin monomer, and, if present, by the type of acyclic olefin monomer. If the cyclic olefin polymer composition is a blend of at least two types of cyclic olefin polymers, the mass ratio of the cyclic olefin polymers also affects the glass transition temperature of the composition. Furthermore, if the cyclic olefin polymer composition is a composition containing at least one cyclic olefin copolymer, the amount of cyclic olefin monomer may be used to individualize the glass transition temperature of the entire composition. It is known that increasing the norbornene content, for example, in norbornene-ethylene copolymers can raise the glass transition temperature. The same applies to other combinations of cyclic olefin monomers and acyclic olefin monomers.

[0028] The cyclic olefin polymer composition may also be a cyclic olefin copolymer composition. The cyclic olefin polymer composition may contain 70-90% by mass, 75-85% by mass, or 75-80% by mass of cyclic olefin units, such as norbornene units, and 10-30% by mass, 15-25% by mass, or 20-25% by mass of acyclic olefin units, such as ethylene units, based on the total mass of the cyclic olefin polymer composition (B). The content of cyclic olefin units in the cyclic olefin polymer (B) is determined when the cyclic olefin polymer (B) is soluble. 13 The content can be determined by 13C NMR spectroscopy, and if the cyclic olefin polymer (B) is insoluble, it can be calculated from the glass transition temperature of the cyclic olefin polymer. If the cyclic olefin polymer (B) is a norbornene-ethylene copolymer and the cyclic olefin units are norbornene units, refer to Macromol. Chem. Phys. 199, 1221-1232 (1998) for its content. In a first preferred embodiment, the glass transition temperature of the cyclic olefin polymer composition may be in the range of 140 to 180°C, as measured according to ISO 11357. More specifically, the glass transition temperature of the cyclic olefin polymer composition may be in the range of 140 to 160°C, more preferably 140 to 155°C, and most preferably 145 to 150°C, as measured according to ISO 11357. In this first preferred embodiment, the cyclic olefin polymer composition may comprise, or essentially consist of, at least a first cyclic olefin polymer (b1) and a second cyclic olefin polymer (b2). The glass transition temperature of the first cyclic olefin polymer (b1) is preferably less than 140°C, more preferably between 60 and 140°C, and particularly between 120 and 140°C, as measured according to ISO 11357. The glass transition temperature of the second cyclic olefin polymer (b2) is preferably greater than 155°C, more preferably between 155°C and 190°C, and particularly between 155°C and 175°C, as measured according to ISO 11357. The first cyclic olefin copolymer, the second cyclic olefin copolymer, and any further cyclic olefin polymers may be melt-blended, preferably in a mass ratio of 1:5 to 5:1, more preferably 1:3 to 3:1, and particularly 1:1, to form the cyclic olefin polymer composition. Using two cyclic olefin polymers with different glass transition temperatures broadens the glass transition temperature step of the polypropylene composition, which is thought to contribute to expanding the processing window of the polypropylene composition. Furthermore, using two cyclic olefin polymers with different glass transition temperatures allows for better control of the material's high-temperature performance.

[0029] In a second preferred embodiment, the glass transition temperature of the cyclic olefin polymer composition may be in the range of 130 to 140°C, as measured according to ISO 11357. In this second preferred embodiment, it may be advantageous if the cyclic olefin polymer composition consists of only one type of cyclic olefin (co)polymer, or essentially consists of only one type of cyclic olefin (co)polymer. The MFR2 (260°C, 2.16 kg) of the cyclic olefin polymer composition (B), when measured according to ISO 1133, is 2 to 50 g / 10 min, preferably 2 to 25 g / 10 min, and more preferably 2 to 15 g / 10 min.

[0030] (C) Nucleating agent The nucleating agent (C) may be present in an amount of 0.000001 to 1% by mass, more preferably 0.00001 to 1% by mass, relative to the total mass of the polypropylene composition. The nucleating agent (C) may be a beta-nucleating agent. When the polypropylene composition contains a branched propylene polymer (D), it is particularly preferable that the nucleating agent is a beta-nucleating agent. The term "beta nucleating agent" refers to any nucleating agent suitable for inducing the crystallization of hexagonal or pseudohexagonal propylene polymers. Mixtures of such nucleating agents may also be used. Suitable types of β-nucleating agents include C5-C8 cycloalkyl monoamines or C6-C 12 Aromatic monoamines and C5-C8 aliphatic, C5-C8 alicyclic, or C6-C 12 Aromatic dicarboxylic acids, for example: N,N'-di-C5-C8-cycloalkyl-2,6-naphthalenedicarboxamide compounds, for example: N,N'-Dicyclohexyl-2,6-Naphthalenedicarboxamide and N,N'-Dicyclooctyl-2,6-Naphthalenedicarboxamide N,N'-di-C5-C8-cycloalkyl-4,4-biphenyldicarboxamide compounds, for example: N,N'-Dicyclohexyl-4,4-biphenyldicarbosamide and N,N'-Dicyclopentyl-4,4-biphenyldicarbosamide, N,N'-di-C5-C8-cycloalkyl-terephthalamide compounds, for example: N,N'-Dicyclohexylterephthalamide and N,N'-Dicyclopentylterephthalamide, N,N'-C5-C8-cycloalkyl-1,4-cyclohexanedicarboxamide compounds, for example: N,N'-Dicyclohexyl-1,4-Cyclohexanedicarboxamide and N,N'-Dicyclohexyl-1,4-Cyclopentanedicarboxamide, C5-C8-cycloalkylmonocarboxylic acid or C6-C 12 - Aromatic monocarboxylic acids and C5-C8-alicyclic or C6-C 12 - Diamine derivative type diamide compounds derived from aromatic diamines, for example: N,N'-C6-C 12 -Arylene-bis-benzamide compounds, for example: N,N'-p-phenylene-bis-benzamide and N,N'-1,5-naphthalene-bis-benzamide N,N'-C5-C8-cycloalkyl-bis-benzamide compounds, for example: N,N'-1,4-cyclopentane-bis-benzamide and N,N'-1,4-cyclohexane-bis-benzamide N,N'-p-C6-C 12 -Arylene-bis-C5-C8-cycloalkylcarboxamide compounds, for example, the following: N,N'-1,5-naphthalene-bis-cyclohexanecarboxamide and N,N'-1,4-phenylene-bis-cyclohexanecarboxamide, and N,N'-C5-C8-cycloalkyl-bis-cyclohexanecarboxamide compounds, for example: N,N'-1,4-cyclopentane-bis-cyclohexanecarboxamide and N,N'-1,4-cyclohexane-bis-cyclohexanecarboxamide C5-C8-alkyl, C5-C8-cycloalkyl, or C6-C 12 -Aryl amino acids, C5-C8-alkyl-, C5-C8-cycloalkyl or C6-C 12 -Aromatic monocarboxylic acid chlorides and C5-C8-alkyl-, C5-C8-cycloalkyl or C6-C 12 - An amino acid derivative type diamide compound derived from the amidation reaction of an aromatic monoamine, for example, the following: N-phenyl-5-(N-benzoylamino)pentanamide and It is N-cyclohexyl-4-(N-cyclohexylcarbonylamino)benzamide.

[0031] Further suitable beta nucleating agents are as follows: Quinacridone-type compounds, for example 5,12-dihydro-quino[2,3-b]acridine-7,14-dione (i.e., quinacridone), dimethylquinacridone, and dimethoxyquinacridone; Quinacridone quinone type compounds, for example Quino[2,3-b]acridine-6,7,13,14(5H,12H)-tetron (i.e., quinacridone quinone), and dimethoxyquinacridone quinone and Dihydroquinacridone-type compounds, for example These are 5,6,12,13-tetrahydroquino[2,3-b]acridine-7,14-dione (i.e., dihydroquinacridone), dimethoxydihydroquinacridone, and dibenzodihydroquinacridone.

[0032] Further suitable β-nucleating agents include dicarboxylates of metals from Group 11a of the periodic table, such as calcium pimephosphate and calcium suberate; as well as mixtures of dicarboxylates with salts of metals from Group 11a of the periodic table. In a particularly preferred embodiment, when the nucleating agent is a β-nucleating agent, the nucleating agent is quinacridone or a quinacridone-quinone type compound. For example, when the nucleating agent is a β-nucleating agent, the nucleating agent is selected from the group consisting of 5,12-dihydro-quino[2,3-b]acridine-7,14-dione, quino[2,3-b]acridine-6,7,13,14(5H,12H)tetron, 5,6,12,13-tetrahydroquino[2,3-b]acridine-7,14-dione and mixtures thereof. By introducing a beta nucleating agent, the microstructure of the polypropylene composition can be controlled. In particular, the generation of amorphous fractions (RAFs) can be limited and regulated, and as a result, the charge mobility in the biaxially oriented film containing the polypropylene composition can be reduced.

[0033] (D) Branched propylene polymer The polypropylene composition preferably further contains branched propylene polymer in an amount of 0.1 to 10% by mass, particularly 0.1 to 5% by mass, relative to the total mass of the polypropylene composition. The branching index g' of the branched propylene polymer is preferably 0.9 or less, preferably 0.8 or less. The branching index g' defines the degree of branching and correlates with the amount of branching of the polymer. The branching index g' of the present invention is defined as a ratio [iV] br / [iV] lin [iV] br [iV] is the intrinsic viscosity of branched propylene polymers. lin is the intrinsic viscosity of a straight-chain propylene polymer with the same mass-average molecular weight as a branched-chain propylene polymer, and the intrinsic viscosity is measured at 135°C in decalin according to DIN ISO 1628 / 1, October 1999. The branching index of branched propylene polymers is typically at least 0.1.

[0034] The term "branched propylene polymer" used in this invention refers to branched polypropylene, which differs from linear polypropylene in that, unlike linear polypropylene, it lacks side chains, whereas linear polypropylene has side chains. The presence of side chains significantly affects the rheology of polypropylene. Therefore, linear polypropylene and branched polypropylene can be clearly distinguished by their flow behavior under stress. Branching can be achieved using a specific catalyst, i.e., a specific single-site catalyst, or by chemical modification. For the preparation of branched propylene polymers obtained using a specific catalyst, see EP 1892264 A1. For branched propylene polymers obtained by chemical modification, see EP 0 879 830 A1. In this case, branched propylene polymer is also called high melt strength polypropylene. The branched propylene polymer according to the present invention is preferably high melt strength polypropylene (HMS-PP) obtained by chemical modification as described in more detail below. Therefore, the terms "branched propylene polymer" and "high melt strength polypropylene (HMS-PP)" may be considered synonymous in this invention. The branched propylene polymer thus produced is also known as long-chain branched propylene polymer. Therefore, the branched propylene polymer of the present invention, i.e., high melt tension polypropylene (HMS-PP), has an F30 melt tension greater than 15.0 cN and a v30 melt spreadability greater than 200 mm / s, preferably an F30 melt tension of 15.0 to 50.0 cN, more preferably 20.0 to 45.0 cN, for example in the range of 25.0 to 40.0 cN, and a v30 melt spreadability of 200 to 300 mm / s, preferably in the range of 215 to 285 mm / s, more preferably in the range of 235 to 275 mm / s. The F30 melt strength and v30 melt spreadability are measured according to ISO 16790:2005.

[0035] Branched propylene polymers can be produced by any number of methods, for example, by treating an unmodified propylene polymer with a pyrolysis radical-forming agent and / or by ionizing radiation, both of which may optionally be followed by treatment with a bifunctional ethylenically unsaturated monomer, such as butadiene, isoprene, dimethylbutadiene, divinylbenzene, or trivinylbenzene.

[0036] As used herein, the term “difunctional ethylenically unsaturated” refers to the presence of two non-aromatic double bonds, such as divinylbenzene or cyclopentadiene. Only difunctional ethylenically unsaturated compounds that can be polymerized with the assistance of free radicals are used. Difunctional unsaturated monomers are not actually “unsaturated” in their chemical bonding state, because each of their two double bonds is used for covalent bonding to the linear polypropylene polymer chain. Examples of branched propylene polymers include, in particular, polypropylene modified by reaction with bismaleimide compounds in the molten state (EP-A-0 574 801 and EP-A-0 574 804), polypropylene modified by treatment with ionizing radiation (EP 0 190 889 A2), polypropylene modified by treatment with peroxide in the solid phase (EP 0 384 431 A2) or in the molten state (EP 0 142 724 A2), polypropylene modified by treatment with a bifunctional ethylenically unsaturated monomer under the action of ionizing radiation (EP A 0 678 527), and polypropylene modified by treatment with a bifunctional ethylenically unsaturated monomer in the presence of peroxide in the molten state (EP A 0 688 817 and EP A 0 450 342). From the list above, branched propylene polymers obtained by treatment with peroxides, particularly with bifunctional ethylenically unsaturated monomers, are preferred. A preferred branched propylene polymer is obtained by mixing linear polypropylene with 0.01 to 3% by mass of a thermally decomposable organic peroxide under the molten conditions of polypropylene, and then heating and melting the mixture. A more preferable branched propylene polymer is obtained by mixing linear polypropylene with 0.01 to 3% by mass of an organic peroxide and 0.2 to 3% by mass of a bifunctional ethylenically unsaturated monomer, which are thermally decomposable under the molten conditions of polypropylene, and then heating and melting the mixture. The difunctional ethylenically unsaturated monomer may be added before or at any point during the heating and melting of the linear polypropylene / peroxide mixture. Alternatively, the difunctional monomer may be added to the linear polypropylene before mixing with the peroxide.

[0037] In a preferred embodiment, the bifunctional monomer is in a gaseous or liquid state absorbed by the polypropylene, which is solid at that time. In a preferred method, branched propylene polymers are prepared by mixing granular or linear propylene polymer with 0.05 to 3% by mass of an organic peroxide (acyl peroxide, alkyl peroxide, perester, and / or peroxycarbonate) that is thermally decomposable under the melting conditions of polypropylene, relative to the linear propylene polymer. The peroxide may optionally be solvated in an inert solvent. The mixing is carried out at a temperature of 30 to 100°C, preferably 60 to 90°C. After mixing with the peroxide, the polypropylene / peroxide mixture is brought into contact with the difunctional ethylenically unsaturated monomer. The difunctional monomer may be in gaseous or liquid form and may be applied in pure or diluted form, for example, diluted with an inert gas or solvated in an organic solvent. The difunctional monomer is absorbed into granular polypropylene at a temperature of 20 to 120°C, preferably 60 to 100°C. The actual adsorption time is 10 to 1000 seconds, preferably 60 to 600 seconds. This typically results in the absorption of 0.01 to 10% by mass and 0.05 to 2% by mass, respectively, of the difunctional monomer relative to the linear propylene polymer. Subsequently, the polypropylene / peroxide / monomer mixture is heated from its adsorption temperature to 210°C in an atmosphere containing an inert gas, such as N2, and / or a bifunctional monomer, until it melts. This causes the peroxide to decompose, generating free radicals in the propylene polymer chains, which then react with the bifunctional monomer. The molten material is heated to 280°C to remove unreacted monomers and decomposition products, and finally the molten material is pelletized. Linear polypropylene includes propylene homopolymers, copolymers of propylene with ethylene and / or α-olefins having 4 to 18 carbon atoms, and mixtures of such homopolymers and copolymers. In preferred embodiments of the present invention, branched propylene polymers are prepared based on propylene homopolymers with low ash content, preferably less than 60 ppm.

[0038] In a more preferred embodiment of the present invention, the branched propylene polymer is prepared based on a high isotactic homopolymer of propylene, such as a high isotactic homopolymer of propylene, where the high isotactic homopolymer of propylene is linear. The particulate linear propylene polymer may be in the form of a powder, granules, or grid. The above method is preferably a continuous process and is carried out in a continuous reactor, mixer, kneader, and extruder. However, it may also be a batch production of modified propylene polymer. Preferably, the bifunctional monomer is absorbed from the gas phase by the linear propylene polymer. The bifunctional ethylenically unsaturated monomer is preferably C4-C4. 10 Diene and / or C7~C 10 These are divinyl compounds. Particularly preferred are butadiene, isoprene, dimethylbutadiene, or divinylbenzene. Peroxides suitable for the above method are described in International Publication No. 2020 / 127862, which is incorporated herein by reference.

[0039] film The present invention further provides a film comprising the above-described polypropylene composition. The film may be a cast film or a biaxially oriented film (BOPP). Furthermore, the thickness of the film is preferably 1 to 1000 μm, more preferably 1 to 300 μm, and most preferably 1 to 250 μm. If the film is a cast film, the film thickness is preferably 100 to 1000 μm, more preferably 200 to 300 μm. If the film is a biaxially oriented film, the film thickness may be 1 to 100 μm, for example, 1 to 10 μm. Current attempts are to provide electrical systems with higher energy density and higher efficiency, and reducing thickness is particularly advantageous. Achieving this goal is facilitated by reducing the spatial requirements for the film within the film capacitor. When provided as a cast film with a thickness of 250 μm, the dielectric breakdown field strength of the film is E b 63.2% is preferably 118 kV / mm or more, preferably 120 kV / mm or more, determined at 90°C according to IEC 60243-1 and IEC 62539. For example, the dielectric breakdown field strength E of a cast film measured at 90°C with a thickness of 250 μm according to IEC 60243-1 and then evaluated according to IEC 62539. b 63.2% may be in the range of 118-250kV / mm, preferably 120-200kV / mm.

[0040] It is even more preferable that the DC conductivity of the cast film is 2 fS / cm or less when the oxygen induction temperature is 250.0°C or higher (the oxygen induction temperature is measured according to ISO 11357) and the DC electrical resistance is taken as the reciprocal of the DC electrical resistance determined according to ASTM D257 at a temperature of 90°C. For example, the DC conductivity of the cast film may be 0.01 to 2 fS / cm.

[0041] The biaxially oriented polypropylene film of the present invention can be obtained in two steps. In the first step, a polypropylene composition is extruded through a flat die to produce a non-oriented film. In the second step, the unstretched film is stretched in the machine direction (MD) and the transverse direction (TD). The stretching or orientation of the unstretched film may be carried out simultaneously in the longitudinal and transverse directions. The two steps of this method may be carried out in a continuous process. After the unstretched film is recovered, it may be cooled and solidified on a rotating cooling roll and then continuously transported from the cooling roll to a stretching device.

[0042] In one embodiment, the biaxially oriented polypropylene film contains at least 80% by mass of the polypropylene composition defined in the present invention, more preferably at least 90% by mass, and even more preferably consists of or essentially consists of the same. The biaxially oriented polypropylene film preferably has a longitudinal stretch ratio of at least 4, preferably at least 5, and transverse stretch ratio of at least 4, preferably at least 5, and more preferably a longitudinal stretch ratio of at least 9 and transverse stretch ratio of at least 5. Biaxially oriented polypropylene films can be prepared by any conventional stretching process known in the industry. Therefore, a method for producing biaxially oriented polypropylene films can preferably utilize the tenter method known in the industry. The tenter method is a method for obtaining an unstretched film by melt-extruding the polypropylene composition of the present invention from a slit die such as a T-die and cooling it on a cooling drum. The film is preheated, for example, on heated metal rolls, then stretched longitudinally between a plurality of rolls with established peripheral speed differences, then both edges are gripped, and the sheet is stretched transversely in an oven by a tenter to obtain a biaxially oriented film. The temperature of the film during longitudinal stretching is preferably controlled to be within the melting point temperature range of the polypropylene composition. Subsequently, the biaxially oriented film can be treated by corona discharge in air, nitrogen, carbon dioxide gas, or a mixture thereof. When the film is metallized for film capacitor applications, corona discharge treatment increases the adhesion strength to the deposited metal. The above stretching process yields a BOPP that is preferably free from mechanically damaged areas, as determined by a scanning electron microscope.

[0043] Capacitor In other embodiments, the present invention relates to a capacitor including the above-described biaxially oriented film. This capacitor including the biaxially oriented film is expected to have a longer lifespan and higher temperature resistance than conventional capacitors. Preferably, the biaxially oriented film is metallized, and the capacitor is a metallized film capacitor. The metallization of the biaxially oriented film can be carried out by any method known in the art, such as evaporation, electrodeposition, melting, ion beam vacuum deposition, sputtering, or ion plating. The thickness of the resulting metal layer may be 100 angstroms (0.01 μm) to 5000 angstroms (0.5 μm). [Examples]

[0044] The properties of the present invention will become clearer and better understood with reference to the accompanying examples. However, the examples are not intended to limit the scope of the present invention. Measurement method Oxygen-inducible temperature (OIT) OIT (Oxygen Induction Temperature) tests were performed using a TA Instruments differential scanning calorimeter (DSC) Q20 in accordance with ISO 11357. Circular samples with a diameter of 5 mm were punched from a 650 ± 50 μm thick compression-molded plaque and then placed in an aluminum pan. The samples were heated to 350°C in an oxygen atmosphere at a flow rate of 50 ml / min (heating rate of 20°C / min). Under these conditions, the stabilizer was consumed until it was completely depleted. At this point, the polymer sample decomposes or oxidizes, releasing further heat (exothermic reaction). The oxidation induction temperature is defined as the temperature at which the inflection point for the exothermic reaction occurs, measured using the standard specifications of the Universal Analysis Software. Each material was measured twice, and the average value was calculated.

[0045] Quantification of fine structure by NMR spectroscopy The isotacticity and comonomer content of the polymer were quantified using quantitative nuclear magnetic resonance (NMR) spectroscopy. quantitative 13 C{ 1 The H}NMR spectrum is, 1 H and 13 For C, the spectra were recorded in solution using a Bruker Advance III 400 NMR spectrometer operated at 400.15 MHz and 100.62 MHz, respectively. All spectra were recorded at 125°C using nitrogen gas at all air pressures. 13 The temperature was recorded using a C-optimized 10mm extended temperature probe head. For polypropylene homopolymers, approximately 200 mg of the material was dissolved in 1,2-tetrachloroethane-d2 (TCE-d2). After the initial sample preparation in a heat block, the NMR tube was further heated in a rotating oven for at least 1 hour to ensure a homogeneous solution. After insertion into a magnet, the tube was rotated at 10 Hz. This setting was chosen primarily for the high resolution required for the quantification of stereoregularity distribution (Busico, V., Cipullo, R., Prog. Polym. Sci. 26 (2001) 443 and Busico, V.; Cipullo, R., Monaco, G., Vacatello, M., Segre, AL, Macromoleucles 30 (1997) 6251). Using a standard single-pulse excitation with NOE and a bilayer Waltz 16 decoupling scheme (Zhou, Z., Kuemmerle, R., Qiu, X., Redwine, D., Cong, R., Taha, A., Baugh, D. Winniford, B., J. Mag. Reson. 187 (2007) 225; Busico, V., Carbonniere, P., Cipullo, R., Pellecchia, R., Severn, J., Talarico, G., Macromol. Rapid Commun. 2007, 28, 11289), a total of 8192 transient events per spectrum (8k) were obtained. quantitative 13 C{ 1 The 1H NMR spectrum was processed and integrated, and the relevant quantitative characteristics were determined from the integral using a proprietary computer program. In polypropylene homopolymers, all chemical shifts are methyl isotactic pentads at 21.85 ppm. <mmmm>This will be used as the internal standard. Characteristic signals corresponding to regio defects (Resconi, L., Cavallo, L., Fait, A., Piemontesi, F., Chem. Rev. 2000, 100, 1253; Wang, WJ., Zhu, S., Macromolecules 33 (2000), 1157; Cheng, HN, Macromolecules 17 (1984), 1950) or comonomers were observed. The stereoregularity distribution was quantified by integrating the methyl region between 23.6 and 19.7 ppm, and corrected for any sites unrelated to the desired stereosynthesis (Busico, V., Cipullo, R., Prog. Polym. Sci. 26 (2001) 443; Busico, V., Cipullo, R., Monaco, G., Vacatello, M., Segre, AL, Macromoleucles 30 (1997) 6251). Specifically, the influence of regio defects and comonomers on the quantification of stereoregularity distribution was corrected by subtracting representative regio defect and comonomer integrals from a specific integral region of the stereoarrangement. Isotacticity is determined at the pentad level, and the percentage of isotactic pentad (mmmm) sequences relative to all pentad sequences is: [mmmm]% = 100 × (mmmm / total pentads) This was reported. The absence of ethylene in high-isotactic propylene homopolymers was obtained using the method of Wang et al. (Wang, WJ., Zhu, S., Macromolecules 33 (2000), 1157) under specified conditions. 13 C{ 1 Quantification was possible through the integration of multiple signals across the entire spectral range of the H} spectrum. This method was chosen for its accuracy, robustness, and ability to account for the presence of regio defects when necessary. By slightly adjusting the integration region, it could be applied to a wider range of comonomer content. The molar ratio of ethylene uptake is as follows: E [mol%] = 100 × fE It is calculated as follows. The mass percentage of ethylene uptake is as follows: E[mass%]=100×(fE×28.05) / ((fE*28.05)+((1-fE)×42.08)) It is calculated as follows. MFR 2 MFR2 is measured according to ISO 1133 (2.16 kg load) at a temperature of either 230°C (for high isotactic homopolymers of propylene) or 260°C (for cyclic olefin polymer compositions). XCS content The XCS content was determined as a mass percentage at 23°C according to ISO 16152. Glass transition temperature Tg The glass transition temperature was measured using a differential scanning calorimeter at a scanning speed of 10 K / min, in accordance with ISO 11357.

[0046] Melting point Tm, crystallization temperature Tc Differential scanning calorimetry (DSC) experiments were performed using a TA Instruments Q2000 instrument calibrated with indium, zinc, and tin according to ISO 11357 / 1. Measurements were performed in accordance with ISO 11357 / 3, at a scanning speed of 10 K / min between -30°C and 225°C, using a heating / cooling / heating cycle with a sample of 5 ± 0.5 mg under a nitrogen atmosphere (50 mL / min). The melting point (Tm) and crystallization temperature (Tc) were obtained as the endothermic and exothermic peaks in the cooling cycle and the second heating cycle, respectively.

[0047] ash The ash content of the polymer was measured according to ISO 3451-1 (1997). Approximately 100 g of polymer was weighed into a platinum crucible. The crucible was then heated in a Bunsen burner flame to slowly burn the polymer. After complete combustion of the polymer, the crucible was cooled, dried, and weighed. The ash content was calculated by dividing the mass of the residue by the mass of the polymer sample. At least two measurements were performed, and if the difference in measurements exceeded 7 ppm, a third measurement was performed. (Dielectric breakdown measurement) Dielectric breakdown strength (also called "dielectric breakdown field strength"), generally expressed in kV / mm, is a characteristic of gases, liquids, and solids. When the electric field exceeds the breakdown field, breakdown occurs through discharge channels in the material, and electrodes are connected. In solids, the material is irreversibly destroyed by discharge, but in gases and liquids, the damage is temporary and reversible. Generally, dielectric breakdown events occur with high randomness; that is, when testing the same sample to establish a dielectric breakdown distribution (see details below), high data variance is observed, and the data often does not follow a normal distribution (see Dissado LA; Fothergill JC "Electrical degradation and breakdown in polymers", IEEE Materials and Devices Series 9, Peter Peregrinus Ltd., 1992). The reason why dielectric breakdown events occur randomly is the nonspecific and localized onset of dielectric breakdown in areas of increased electric field and areas of low dielectric breakdown strength (see above). In general, structural heterogeneity of materials, the inclusion of contaminants or voids (see Chen G.; Davies AE. The influence of defects on the short-term breakdown characteristics and long-term DC performance of LDPE insulation. IEEE Transactions on Electrical Insulation, 2000, 7, 401-407), and surface roughness (Rytoluoto L; Gitsas A.; Pasanan S.; Lahti K. Effect of film structure and morphology on the dielectric breakdown characteristics of cast and biaxially oriented polypropylene films. European Polymer Journal, 2017, 95, 606-624) can be potential failure sites, and these are unavoidable in industrial production.

[0048] Dielectric breakdown test The breakdown strength of the solid was tested using a short-voltage ramp test. A thin test specimen (250 μm thick) of cast film was placed between electrodes at a temperature of 90°C, and the voltage was increased (linearly, exponentially, stepwise, etc.) until dielectric breakdown occurred. The voltage at which dielectric breakdown occurs is the dielectric breakdown voltage (kV) of the test specimen (see IEC 60234-1 (2013) - Electric strength of insulating materials - Test methods - Part 1 : Tests at power frequencies). Subsequently, the sample thickness at the fracture point was measured to obtain the fracture strength Eb (kV / mm). This test was repeated on similarly prepared specimens of the material to obtain the fracture distribution of the material (see Rytoluoto T; Gitsas A.; Pasanan S.; Lahti K. Effect of film structure and morphology on the dielectric breakdown characteristics of cast and biaxially oriented polypropylene films. European Polymer Journal, 2017, 95, 606-624).

[0049] Statistical evaluation IEC 62539, for evaluating breakdown distributions (also known as "DBDs"), includes the two-parameter Weibull distribution (2-Weibull), the three-parameter Weibull distribution (3-Weibull), the log-normal distribution, and the first asymptotic extremum distribution (1 AEV). Generally, when the breakdown mechanism is unknown, the statistical distribution is selected primarily through fitting quality.

number

[0050] DC conductivity DC conductivity was calculated as the reciprocal of the DC electrical resistance measured at 90°C according to ASTM D257. material The example materials were prepared using the polymers listed in Table 1 below. Table 1: Polymers used in the production of CE1 and IE1-IE2

[0051] [Table 1] The above polymers were combined in the amounts shown in Table 2 below and melt-blended to form Example Materials CE1 and IE1-IE4. Example Materials IE1-IE4 are polypropylene compositions containing a certain amount of one or more cyclic olefin polymers. Example Material CE1 does not contain a cyclic olefin polymer. Table 2: Composition of sample materials CE1 and IE1-IE4

[0052] [Table 2] The material used in this example was obtained in pelletized form. The pellets were converted into cast film using a small laboratory cast film line manufactured by COLLIN Lab&Pilot Solutions GmbH. This line consists of an extruder equipped with a φ30 mm screw with an L / D ratio of 30. The extruder temperature was set to 235°C, and the melting temperature was 235°C, recorded after 45 minutes of process stabilization. A 300 mm wide die followed the extruder. The die had a flexible die lip with a die gap of 0.5–1.5 mm. The line was operated at a constant throughput of 8 kg / h and a line speed of 10 m / min. The film was cut to a width of 270 mm. The cast film was produced with a thickness of 250 μm. Furthermore, the pellets were compressed and molded to form plaques with a thickness of 650 ± 50 μm. The properties of the materials in the examples were measured on the cast film or plaque as appropriate, according to the measurement method outlined above. The results are shown in Table 3. Table 3: Characteristics of CE1, IE1-IE4

[0053] [Table 3] As can be concluded from Table 3, the dielectric breakdown field strength of the cast film is increased by up to approximately 20% when a portion of the HIPP is replaced with COC or a COC blend (134 kV / mm for IE2 and 113.5 kV / mm for CE1). At the same time, the introduction of COC or a COC blend also improves the thermal stability of the films produced from each polypropylene composition. This is reflected by an increase of at least 2°C in the oxidation induction temperature (251.0°C for IE3 compared to 248.6°C for CE1). Finally, importantly, the DC resistivity is improved, as the DC conductivity of Examples IE1-IE4 of the present invention is considerably lower than that of CE1 (5.2). Overall, these favorable trends make the biaxially oriented film containing the polypropylene composition according to the present invention suitable for the manufacture of capacitors with excellent durability and lifespan.< / mmmm> < / mmmm>

Claims

1. below: (A) High isotactic homopolymer of propylene having a content of 70 to less than 95% by mass, (B) A cyclic olefin polymer composition having a content of 5 to less than 30% by mass, and (C) A nucleating agent having a content of 0.0000001 to 1% by mass, A polypropylene composition comprising, where, The contents of (A), (B), and (C) are, each, relative to the total mass of the polypropylene composition.

2. A branched propylene polymer whose content relative to the total mass of the polypropylene composition is 0.1 to 10% by mass, or a branched propylene polymer whose branching index g' is 0.9 or less or 0.8 or less. A polypropylene composition according to claim 1, comprising: Here, the branching index g' is [iV] ｂｒ / [iv] ｌｉｎ It is expressed as the ratio of the above [iV] ｂｒ The intrinsic viscosity of the branched propylene polymer is [iV] ｌｉｎ A polypropylene composition wherein the intrinsic viscosity is the same as that of a straight-chain propylene polymer with the same mass-average molecular weight as the branched-chain propylene polymer, and the intrinsic viscosity is measured in decalin at 135°C according to DIN ISO 1628 / 1, October 1999.

3. below: (A) High isotactic homopolymers having a content of 75 to less than 90% by mass, (B) A cyclic olefin polymer composition having a content of 10 to less than 25% by mass, (C) A nucleating agent having a content of 0.0000001 to 1% by mass, and (D) comprising the branched propylene polymer in a content of 0.1 to 5% by mass, Here, the content of (A) to (D) is, each, relative to the total mass of the polypropylene composition. The polypropylene composition according to claim 2.

4. A highly isotactic homopolymer of propylene (A) The material contains one or more additives, the content of which is 0 to 2.0% by mass or 0.05 to 0.5% by mass relative to the mass of the propylene high isotactic homopolymer (A), Here, the one or more additives are preferably selected from the group consisting of antioxidants, stabilizers, acid scavengers, and combinations thereof. The polypropylene composition according to any one of claims 1 to 3.

5. The nucleating agent (C) is a beta nucleating agent, Preferably, these are 5,12-dihydro-quino[2,3-b]acridine-7,14-dione, quino[2,3-b]acridine-6,7,13,14(5H,12H)-tetron, 5,6,12,13-tetrahydroquino[2,3-b]acridine-7,14-dione, and mixtures thereof. A polypropylene composition according to any one of claims 1 to 4.

6. The cyclic olefin polymer composition (B) is a cyclic olefin copolymer composition. Preferably, a cyclic olefin copolymer composition, the following: Cyclic olefin units, such as norbornene units, having a content of 70-90% by mass, 75-85% by mass, or 75-80% by mass, and acyclic olefin units, such as ethylene units, having a content of 10 to 30% by mass, 15 to 25% by mass, or 20 to 25% by mass, Here, the content is, each relative to the total mass of the cyclic olefin copolymer composition (B), The polypropylene composition according to any one of claims 1 to 5.

7. The polypropylene composition according to any one of claims 1 to 6, wherein the glass transition temperature of the cyclic olefin polymer composition (B) is in the range of 140 to 180°C, 140 to 160°C, 140 to 155°C, or 145 to 150°C, as measured according to ISO 11357.

8. MFR of cyclic olefin polymer composition (B) ２ The polypropylene composition according to any one of claims 1 to 7, wherein the (260°C) concentration, when measured according to ISO 1133, is 2 to 50 g / 10 min, 2 to 25 g / 10 min, or 2 to 15 g / 10 min.

9. The cyclic olefin polymer composition (B) comprises at least a first cyclic olefin polymer (b1) and a second cyclic olefin polymer (b2), where, The glass transition temperature of the first cyclic olefin polymer (b1) is preferably less than 140°C or between 60°C and 140°C, as measured according to ISO 11357, and the glass transition temperature of the second cyclic olefin polymer (b2) is preferably greater than 155°C or greater than 155°C to 190°C, as measured according to ISO 11357. The polypropylene composition according to any one of claims 1 to 8.

10. A highly isotactic homopolymer of propylene (A) is as follows: - The isotactic pentad fraction content is １３ When measured by 13C NMR, the percentages are 93–99.5%, 95–99.0%, or 96–98.5%; -0.4 to 10 g / 10 min or 0.5 to 5 g / 10 min; - The ash content is 60 ppm or less, 30 ppm or less, or 20 ppm or less, as measured according to ISO 3451-1 (1997); - The crystallization temperature (Tc), as measured according to ISO 1133, is 110–130°C, 110–120°C, or 250–250°C; A polypropylene composition according to any one of claims 1 to 9, wherein at least one of the following is present.

11. A cast film comprising the polypropylene composition according to any one of claims 1 to 10.

12. Dielectric breakdown field strength E ｂ 63.2% are 118 kV / mm or higher or 120 kV / mm or higher, where the dielectric breakdown field strength E ｂ The cast film according to claim 11, wherein 63.2% is determined at 90°C in accordance with IEC 60243-1 and IEC 62539.

13. The oxygen induction temperature is 250.0°C or higher when measured according to ISO 11357, and The DC conductivity, obtained as the reciprocal of the DC electrical resistance, is less than 2 fS / cm when measured at 90°C according to ASTM D257. The cast film according to claim 11 or 12.

14. A biaxially oriented film comprising the polypropylene composition according to any one of claims 1 to 10.

15. A capacitor comprising a biaxially oriented film as described in claim 14.

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