JP6926827B2 - Olefin laminated film and film capacitors - Google Patents

Description

The present invention relates to an olefin-based laminated film suitable for packaging, industrial use, etc., and more specifically, an olefin-based laminated film having dimensional stability and insulation performance in a high temperature region suitable for high-voltage capacitor applications and the like. Regarding film.

In recent years, most of various electric equipments have been converted to inverters, and along with this, there is an increasing demand for smaller capacitors and larger capacities. In particular, in response to the demand for automobile applications (including hybrid car applications), solar power generation, and wind power generation applications, the withstand voltage of the film is improved, productivity and workability are maintained, and further thinning and heat resistance are achieved. It is becoming an indispensable situation. As for heat resistance, in power semiconductor applications using SiC, the operating environment temperature becomes high, so that it is required that the capacitor can be used in a high temperature environment exceeding 120 ° C. However, as described in Non-Patent Document 1, it is said that the upper limit of the operating temperature of a capacitor using a polypropylene film is about 110 ° C., and it is extremely difficult to stably maintain the withstand voltage in such a high temperature environment. It is becoming.

In order to reduce the size of the film capacitor and improve the heat resistance, it is conceivable to use a thin film and a film having a high relative permittivity, or to use a film having a glass transition temperature exceeding the capacitor operating environment temperature range. For example, by using a laminated structure in which two types of films having different relative permittivity are alternately laminated, one film uses a cycloolefin polymer whose glass transition temperature exceeds 130 ° C., and the other film uses a polypropylene film. A laminate that can maintain a large capacitance while having heat resistance and withstand voltage has been proposed (for example, Patent Document 1). However, since the film of Patent Document 1 is not a coextrusion laminate but a laminate in which a cycloolefin polymer layer is formed on a base polypropylene film by a coating method, peeling between film layers may occur in a high temperature use environment, and stereoregulation may occur. Since polypropylene resin with low properties is used, the withstand voltage is insufficient, and it is hard to say that the performance and reliability of a capacitor are sufficient. On the other hand, a high-rigidity film obtained by co-extruding and stretching a cycloolefin polymer and polypropylene has been proposed (for example, Patent Document 2). However, the film of Patent Document 2 has a low elongation at break in terms of mechanical properties, cracks or breaks occur during processing of a capacitor element, and is not heat-treated after stretching, so that dimensional stability in a high temperature environment can be obtained. However, it was difficult to say that the workability of the capacitor element and the performance and reliability of the capacitor were sufficient, such as insufficient withstand voltage.

Japanese Unexamined Patent Publication No. 2015-012076 Japanese Unexamined Patent Publication No. 06-336526

Nikkei Electronics, September 17, 2012, p.57-62

The present inventors have arrived at the present invention as a result of diligent studies to solve the above problems. That is, the problem to be solved by the present invention is excellent in withstand voltage and reliability at high temperature, especially in high voltage capacitor applications, and dimensional stability and insulation performance in a high temperature region suitable for such capacitor applications. It is to provide the possessed olefin-based laminated film.

Problems described above, the configuration layer containing polypropylene resin on both surfaces of the base layer portion (B layer) comprising a cyclic olefin resin (A layer) is laminated, the dielectric breakdown voltage V (23) at 23 ° C. (V / The ratio of the breakdown voltage V (130) (V / μm) at 130 ° C. to V (130) / V (23) ≥ 0.6
It can be achieved by an olefin-based laminated film characterized by satisfying the above.

According to the present invention, it is possible to provide an olefin-based laminated film having dimensional stability and insulation performance in a high temperature region suitable for capacitor applications and the like, and a method for producing them. Therefore, packaging applications, tape applications, cable wrapping, etc. It can be applied to various applications such as electrical applications such as capacitors and capacitors, and can exhibit withstand voltage and reliability at high temperatures, especially in high voltage capacitor applications.

In the olefin-based laminated film of the present invention, the base layer portion (hereinafter, may be referred to as B layer) contains a cyclic olefin-based resin, and a constituent layer (hereinafter, may be referred to as A layer) containing a polypropylene-based resin on at least one surface thereof may be used. It is important to use an olefin-based laminated film provided with). As a result of diligent studies by the inventors, in the laminated film, the cyclic olefin resin of the B layer is responsible for high heat resistance and dimensional stability in a high temperature environment, and the A layer containing the polypropylene resin on at least one side is capacitor-processed. It was found that it is possible to exhibit the action that is responsible for the workability required at times and the high withstand voltage performance required for capacitors.

Examples of the method for laminating the olefin-based laminated film of the present invention include a method of laminating films by laminating, a feed block method and a multi-manifold method by coextrusion, and a method by coating, but from the viewpoint of production efficiency and cost. A laminating method based on a laminating method by coextrusion (for example, melt coextrusion) is preferable. Further, the lamination is preferably a structure in which two or more layers are laminated in the film thickness direction, and specifically, a structure in which at least one surface layer is an A layer or more, for example, a two-layer structure of an A layer / a B layer. More preferably, it has a three-layer structure of A layer / B layer / A layer and a structure of four or more layers in which the A layer is the outermost layer on both surfaces of the film. Here, in the case of a configuration in which two or more layers are laminated in the thickness direction, the ratio of the thickness of the A layer to the total thickness of the film (if there are A layers on both surface layers, the thickness ratio of both A layers combined). Is preferably 10% to 90%, more preferably 20% to 70%, from the viewpoint of controlling the film forming property and the surface shape. If the proportion of the A layer is too large, the withstand voltage resistance in a high temperature environment may be lowered, while if the proportion of the A layer is too small, the film may be easily broken during film formation. Here, the layer A is defined as a constituent layer containing a polypropylene resin, and the polypropylene resin content ratio is preferably 95% by mass or more, more preferably 96% by mass or more, and further preferably 97% by mass or more. On the other hand, the B layer is defined as a constituent layer containing a cyclic olefin resin, and the content ratio of the cyclic olefin resin is preferably 95% by mass or more, more preferably 96% by mass or more, and further preferably 97% by mass or more. .. By laminating polypropylene-based resin on at least one surface, it is possible to biaxially stretch the cyclic olefin-based resin in the inner layer, and it is possible to roughen the surface in order to impart appropriate workability during capacitor processing. Become.

The olefin-based laminated film of the present invention has a ratio of the breakdown voltage V (23) (V / μm) at 23 ° C. to the breakdown voltage V (130) (V / μm) at 130 ° C.
V (130) / V (23) ≥ 0.6
Is important. In high-voltage capacitor applications, V (130) / V (23) ≥ 0.65 is more preferable, and V (130) is even more preferable, from the viewpoint of obtaining a film having excellent withstand voltage resistance and reliability at high temperatures. ) / V (23) ≥ 0.70, most preferably V (130) / V (23) ≥ 0.75. When V (130) / V (23) <0.6, when a capacitor is used, the capacitance tends to decrease or short circuit fracture occurs in a high temperature environment, which causes a decrease in withstand voltage and tends to reduce reliability. .. Here, in order to control the V (130) / V (23) relationship of the olefin-based laminated film within the above range, a configuration of two or more layers having at least one surface layer as the A layer, and an MFR described later, are used. A cyclic olefin resin composition containing a blend of different cyclic olefin resins or an elastomer is used, and the temperature of the heat treatment and relaxation treatment steps after biaxial stretching is 140 ° C or higher, and the melting point of the polypropylene resin is -5 ° C or lower. It can be achieved by controlling the temperature of.

The cyclic olefin resin used for the olefin laminated film of the present invention will be described. The cyclic olefin resin is a resin obtained by polymerizing from a cyclic olefin as a monomer and having an alicyclic structure in the main chain of the polymer, and is derived from the cyclic olefin monomer in 100% by mass of the polymer of the cyclic olefin resin. It means a polymer in an embodiment in which the total amount of components (constituent units) exceeds 50% by mass and is 100% by mass or less.

Cyclic olefin monomers include monocyclic olefins such as cyclobutene, cyclopentene, cycloheptene, cyclooctene, cyclopentadiene, and 1,3-cyclohexadiene, bicyclo [2,2,1] hept-2-ene, and 5-methyl-bicyclo [ 2,2,1] hepta-2-ene, 5,5-dimethyl-bicyclo [2,2,1] hept-2-ene, 5-ethyl-bicyclo [2,2,1] hept-2-ene, 5-butyl-bicyclo [2,2,1] hept-2-ene, 5-ethylidene-bicyclo [2,2,1] hept-2-ene, 5-hexyl-bicyclo [2,2,1] hept- 2-ene, 5-octyl-bicyclo [2,2,1] hept-2-ene, 5-octadecil-bicyclo [2,2,1] hept-2-ene, 5-methylidene-bicyclo [2,2] 1] Bicyclic olefins such as hept-2-ene, 5-vinyl-bicyclo [2,2,1] hept-2-ene, 5-propenyl-bicyclo [2,2,1] hept-2-ene, tricyclo [4,3,0,1 ^2.5 ] Deca-3,7-diene, tricyclo [4,3,0,1 ^2.5 ] Deca-3-ene, tricyclo [4,3,0,1 ^{2. 5} ] Undeca-3,7-diene, tricyclo [4,3,0,1 ^2.5 ] Undeca-3,8-diene, tricyclo [4,3,0,1 ^2.5 ] Undec-3-ene, 5-Cyclopentyl-bicyclo [2,2,1] hept-2-ene, 5-cyclohexyl-bicyclo [2,2,1] hept-2-ene, 5-cyclohexenylbicyclo [2,2,1] hept- Tricyclic olefins such as 2-ene and 5-phenyl-bicyclo [2,2,1] hepta-2-ene, tetracyclo [4,5,0,1 ^2.5 , 1 ^7.10 ] dodeca-3-ene , 8-methyl tetracyclo ^{[4,4,0,1 2.5, 1 7.10]} dodeca-3-ene, 8-ethyl-tetracyclododecene ^{[4,4,0,1 2.5, 1 7.10} ] dodeca-3-ene, 8-methylidene-tetracyclo ^{[4,4,0,1 2.5, 1 7.10]} dodeca-3-ene, 8-ethylidene tetracyclododecene [4,4,0,1 ^{2 .5} , 1 ^7.10 ] Dodeca-3-ene, 8-vinyltetracyclo [4,5,0,1 ^2.5 , 1 ^7.10 ] Dodeca-3-ene, 8-propenyl-tetracyclo [4, 4,0,1 ^{2.5, 1 7.10]} dodeca-3-ene such tetracyclic-olefin Fin, and 8-cyclopentyl - tetracyclo ^{[4,4,0,1 2.5, 1 7.10]} dodeca-3-ene, 8-cyclohexyl - tetracyclo [4,4,0,1 ^2.5, 1 ^7.10 ] Dodeca-3-ene, 8-cyclohexenyl-tetracyclo [4,5,0,1 ^2.5 , 1 ^7.10 ] Dodeca-3-ene, 8-phenyl-cyclopentyl-tetracyclo [4,4] ^{0,1 2.5, 1 7.10]} dodeca-3-ene, tetracyclo ^{[7,4,1 3.6,} 0 ^{1.9, 0 2.7]} tetradeca -4,9,11,13- tetraene, tetracyclo ^{[8,4,1 4.7,} 0 1.10 ^{0 3.8]} pentadeca -5,10,12,14- tetraene, pentacyclo ^{[6,6,1 3.6, 0 2.7} , ^{0 9.14]} -4-hexadecene, pentacyclo ^{[6,5,1,1 3.6,} 0 ^{2.7, 0 9.13]} -4-pentadecene, pentacyclo [7,4,0,0 ^{2. 7, 1 3.6, 1 10.13]} -4-pentadecene, heptacyclo ^{[8,7,0,1 2.9,} 1 ^{4.7, 1 11.17, 0 3.8, 0 12.16]} 5-eicosene, heptacyclo ^{[8,7,0,1 2.9,} 0 ^{3.8, 1 4.7,} 0 ^{12.17, 1 13.16]} 14-eicosene, tetrameric, etc., such as cyclopentadiene Polycyclic olefins and the like can be mentioned. These cyclic olefin monomers can be used alone or in combination of two or more.

Among the above, the cyclic olefin monomers include bicyclo [2,2,1] hept-2-ene (hereinafter referred to as norbornene) and tricyclo [4,3,0,12. 5] Deca-3-ene and other tricyclic olefins having 10 carbon atoms (hereinafter referred to as tricyclodecene), tetracyclo [4,4,5,12.5,17.10] dodeca-3-ene and the like. A tetracyclic olefin having 12 carbon atoms (hereinafter referred to as tetracyclododecene), cyclopentadiene, or 1,3-cyclohexadiene is preferably used.

As for the cyclic olefin resin, if the total amount of the components derived from the cyclic olefin monomer is more than 50% by mass and 100% by mass or less in 100% by mass of the polymer of the cyclic olefin resin, only the cyclic olefin monomer is polymerized. Any resin (hereinafter, sometimes referred to as COP) or a resin obtained by copolymerizing the cyclic olefin monomer and the chain olefin monomer (hereinafter, sometimes referred to as COC) may be used.

Examples of the method for producing COP include known methods such as addition polymerization of cyclic olefin monomers or ring-opening polymerization. For example, after ring-opening metathesis polymerization of norbornene, tricyclodecene, tetracyclodecene, and derivatives thereof. Examples thereof include a method of hydrogenation, a method of addition-polymerizing norbornene and its derivatives, a method of 1,2-, 1,4-addition polymerization of cyclopentadiene and cyclohexadiene, and then hydrogenation. Among these, from the viewpoint of productivity and moldability, a resin obtained by subjecting norbornene, tricyclodecene, tetracyclodecene, and a derivative thereof to ring-opening metathesis polymerization and then hydrogenating is most preferable.

In the case of COC, preferred chain olefin monomers include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 3-methyl-1-pentene, 3-methyl-1-pentene and 3-ethyl-1. -Pentene, 4-methyl-1-pentene, 4-methyl-1-hexene, 4,4-dimethyl-1-hexene, 4,4-dimethyl-1-pentene, 4-ethyl-1-hexene, 3 -Ethyl-1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene and the like can be mentioned. Among these, ethylene can be particularly preferably used from the viewpoint of productivity and cost. Further, as a method for producing a resin obtained by copolymerizing a cyclic olefin monomer and a chain olefin monomer, a known method such as addition polymerization of a cyclic olefin monomer and a chain olefin monomer can be mentioned. Examples thereof include a method of addition polymerization of ethylene. Among them, a copolymer of norbornene and ethylene is most preferable from the viewpoint of productivity and moldability.

The cyclic olefin resin used in the olefin-based laminated film of the present invention has a melt flow rate (MFR) of 0.5 to 35 g / 10 minutes (260 ° C., 21.18 N load), particularly preferably 2 to 30 g / 10 minutes. Those in the range of (260 ° C., 21.18 N load) are preferable from the viewpoint of film forming property. Here, MFR is an index indicating the melt viscosity of the resin defined in JIS K 7210 (1999), and is widely used as a physical property value indicating the characteristics of polyolefin. The olefin-based laminated film of the present invention preferably has a resin structure in which cyclic olefin-based resins having different MFRs are blended with each other. Different MFRs mean that the resins have different average molecular weights and molecular weight distributions, and by blending these resins, the entanglement between the molecular chains is increased, and the stretching breakage during film formation is suppressed. The area stretch ratio can be increased, and the mechanical properties and withstand voltage resistance of the film can be improved. In the present invention, it is preferable to blend cyclic olefin resins having a large difference in MFR, and the difference in MFR is 5 g / 10 minutes or more, more preferably 10 g / 10 minutes or more, and further preferably 15 g / 10 minutes or more. .. The upper limit is 50 g / 10 minutes from the viewpoint of film forming property.

Further, as the B layer in the olefin-based laminated film of the present invention, a cyclic olefin-based resin in which a styrene-based elastomer is contained in the cyclic olefin-based resin may be used. The styrene-based elastomer is not particularly limited as long as the styrene unit is included as the copolymer unit, and conventionally known ones can be used. Examples of conventionally known styrene-based elastomer resins include SIBS (styrene-isobutylene-styrene copolymer), SEBS (styrene-ethylene-butylene-styrene copolymer), SEPS (styrene-propylene-styrene copolymer), and the like. Examples include, but are not limited to, SEEPS (hydrogenated styrene-isoprene butadiene-styrene copolymer). In the present invention, by preferably using a cyclic olefin resin composition containing SEBS as a styrene-based elastomer, it is possible to impart stretchability during biaxial stretching and appropriate processability during capacitor processing. The content of the styrene-based elastomer is 10% by mass or less, preferably 8% by mass or less, and more preferably 5% by mass or less with respect to 100% by mass of the cyclic olefin-based resin. When the content of the styrene-based elastomer exceeds 10% by mass, the mechanical properties of the film may be deteriorated, the thermal dimensional stability and the dielectric breakdown voltage at high temperature may be lowered.

The glass transition temperature of the cyclic olefin-based resin used for the olefin-based laminated film of the present invention, the blended resin of cyclic olefin-based resins having different MFRs, and the cyclic olefin-based resin composition containing an elastomer or the like in the cyclic olefin-based resin is determined. From the viewpoint of having dimensional stability and insulation performance in a high temperature region suitable for capacitor applications and the like, 125 ° C. or higher is preferable, 130 ° C. or higher, and even more preferably 135 ° C. or higher. If the glass transition temperature is less than 125 ° C, the thermal dimensional stability and the breakdown voltage at high temperature may be reduced. The upper limit is not particularly limited, but is set to 200 ° C. from the viewpoint of film forming property.

The olefin-based laminated film of the present invention is a polypropylene-based resin on at least one side, preferably both sides of the B layer containing a cyclic olefin-based resin (including a blend resin of different cyclic olefin-based resins and a cyclic olefin-based resin; the same applies hereinafter). From the viewpoint that laminating the A layer containing the above enables biaxial stretching of the cyclic olefin resin in the inner layer portion and can form a surface (roughened surface) for imparting appropriate workability during capacitor processing. More preferred. The olefin-based laminated film of the present invention preferentially forms α-crystal spherulites by setting the temperature at which it is solidified on a cooling drum after melt extrusion in the film manufacturing process to less than 60 ° C., preferably less than 40 ° C. In the stretching process, surface irregularities can be imparted by the composition ratio of particles and a blended resin of polypropylene and polypropylene incompatible resin without relying on crystal transformation from β crystal to α crystal, and with a thin film. Even if it exists, it is excellent in processing suitability for polypropylene elements and can exhibit high withstand voltage even in a high temperature environment. Further, the olefin-based laminated film of the present invention may be configured to contain particles in the A layer, and β-crystal spherulites are formed by raising the temperature of solidification on a cooling drum after melt extrusion to 60 ° C. or higher in the film manufacturing process. A method of forming irregularities on the film surface by forming crystals and transforming β crystals into α crystals in a stretching step can be preferably used.

Further, the olefin-based laminated film of the present invention utilizes a domain structure formed by the resins by forming the A layer into a resin structure in which a polypropylene resin and a thermoplastic resin incompatible with polypropylene are blended. Surface irregularities may be imparted to the A layer. For example, as a thermoplastic resin incompatible with polypropylene, a polymethylpentene resin or the like can be preferably used.

Polypropylene, which is preferable as the polypropylene-based resin contained in the A layer of the olefin-based laminated film of the present invention, is usually used for packaging materials and capacitors, but preferably has a cold xylene-soluble portion (hereinafter, CXS) of 4. It is preferably mass% or less. If these conditions are not satisfied, the film-forming stability may be inferior, or voids may be formed in the film when the biaxially stretched film is produced, and the breakdown voltage may be significantly reduced.

Here, the cold xylene-soluble portion (CXS) refers to a polypropylene component dissolved in xylene when the film is completely dissolved with xylene and then precipitated at room temperature, and has low stereoregularity. It is considered that it corresponds to a component that is difficult to crystallize because of its low molecular weight. If a large amount of such a component is contained in the resin, problems such as a decrease in the withstand voltage of the film may occur. Therefore, the CXS is preferably 4% by mass or less, more preferably 3% by mass or less, and particularly preferably 2% by mass or less. In order to obtain polypropylene having such CXS, a method of increasing the catalytic activity when obtaining the resin, a method of washing the obtained resin with a solvent or the propylene monomer itself, or the like can be used.

For polypropylene, the melt flow rate (MFR) is more preferably in the range of 1 to 10 g / 10 minutes (230 ° C., 21.18 N load), and particularly preferably 2 to 5 g / 10 minutes (230 ° C., 21.18 N load). Is preferable from the viewpoint of film forming property. In order to set the MFR to the above value, a method of controlling the average molecular weight or the molecular weight distribution is adopted.

Further, polypropylene is mainly composed of a homopolymer of propylene, but may contain a copolymerization component due to other unsaturated hydrocarbons as long as the object of the present invention is not impaired, or a polymer in which propylene is not alone. May be blended. Examples of the monomer components constituting such copolymerization components and blends include ethylene, propylene (in the case of a copolymerized blend), 1-butene, 1-pentene, 3-methylpentene-1, 3-methylbutene. 1,1-Hexene, 4-methylpentene-1,5-ethylhexene-1,1-octene, 1-decene, 1-dodecene, vinylcyclohexene, styrene, allylbenzene, cyclopentene, norbornene, 5-methyl-2- Norbornene and the like can be mentioned. From the viewpoint of withstand voltage and heat resistance, the copolymerization amount or the blend amount is preferably less than 1 mol% in the copolymerization amount and less than 10% by mass in the blend amount.

Further, polypropylene has various additives such as a crystal nucleating agent, an antioxidant, a heat stabilizer, a slip agent, an antistatic agent, an antiblocking agent, a filler, and a viscosity modifier, as long as the object of the present invention is not impaired. , Anti-coloring agent, resin other than polypropylene, etc. can also be contained.

Among these, selection of the type and amount of antioxidant is important from the viewpoint of long-term heat resistance. That is, the antioxidant is preferably a phenolic agent having steric hindrance, and at least one of them is a high molecular weight type having a molecular weight of 500 or more. Specific examples thereof include various examples. For example, 1,3,5-trimethyl-2,4,6-with 2,6-di-t-butyl-p-cresol (BHT: molecular weight 220.4). Tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene (eg, BASF Irganox® 1330: molecular weight 775.2) or tetrakis [methylene-3 (3,5-di-t) -Butyl-4-hydroxyphenyl) propionate] methane (for example, Irganox® 1010 manufactured by BASF: molecular weight 1,177.7) and the like are preferably used in combination. The total content of these antioxidants is preferably in the range of 0.03 to 1.0% by mass with respect to the total amount of polypropylene. If the amount of antioxidant is too small, long-term heat resistance may be inferior. If too much antioxidant is used, blocking at high temperature due to bleed-out of these antioxidants may adversely affect the capacitor element. A more preferable content is 0.1 to 0.9% by mass, and particularly preferably 0.2 to 0.8% by mass.

The olefin-based laminated film of the present invention preferably has a mesopentad fraction of the polypropylene-based resin contained in the layer A of 0.95 or more and a melting point of more than 160 ° C. The mesopentad fraction is more preferably 0.96 or more, further preferably 0.97 or more, and even more preferably 0.98 or more. The mesopentad fraction is an index showing the stereoregularity of the polypropylene crystal phase measured by the nuclear magnetic resonance method (NMR method), and the higher the value, the higher the crystallinity and the higher the melting point, and in a high temperature environment. This is preferable because the insulation breakdown voltage can be improved. The upper limit of the mesopentad fraction is not specified. As described above, in order to obtain polypropylene having a high mesopentad fraction and a high melting point, a method of appropriately selecting an electron donating component in a so-called Ziegler-Natta catalyst is preferably adopted. When the mesopentad fraction of polypropylene resin is less than 0.95, the regularity of polypropylene is low, which causes a decrease in the strength and insulation breakdown voltage of the film in a high temperature environment, a process of forming a metal film by vapor deposition, and capacitor element winding. In the removal process, the film may break during film transportation. The melting point of the polypropylene resin is more preferably 163 ° C. or higher, further preferably 165 ° C. or higher. When the melting point is 160 ° C. or lower, the crystallinity is low, which causes a decrease in the dielectric breakdown voltage of the film in a high temperature environment, or in the process of forming a metal film by thin film deposition or in the process of winding a capacitor element, the film breaks during film transfer. May be done.

When the olefin-based laminated film of the present invention contains particles, inorganic particles and organic particles are preferably used. Examples of the inorganic particles include metal oxides such as silica, alumina, titania and zirconia, barium sulfate, calcium carbonate, aluminum silicate, calcium phosphate, mica, kaolin and clay. Among these, metal oxides such as silica, alumina, titania and zirconia and calcium carbonate are preferable. Examples of the organic particles include cross-linked particles of polymethoxysilane-based compounds, cross-linked particles of polystyrene-based compounds, cross-linked particles of acrylic-based compounds, cross-linked particles of polyurethane-based compounds, cross-linked particles of polyester-based compounds, cross-linked particles of fluorine-based compounds, or A mixture of these can be mentioned.

The average particle size of the inorganic particles and the organic particles is preferably in the range of 0.03 to 10 μm. The average particle size is more preferably 0.05 to 6 μm, still more preferably 0.07 to 4 μm, and most preferably 0.1 to 2 μm. If the average particle size is less than 0.03 μm, the surface roughness becomes small, which may result in insufficient handleability and deterioration of capacitor reliability. On the other hand, if it exceeds 10 μm, the film is liable to tear or fall off from the thin film, and insulation defects are liable to occur.

Here, as a method for measuring the average particle size of inorganic particles or organic particles, the weight average diameter is calculated and adopted by using the equivalent circle diameter obtained by image processing from the transmission electron micrograph of the particles.

The content of the particles is preferably 0.01 to 1 part by mass when the entire layer A containing the polypropylene resin is 100 parts by mass. If the content is less than 0.01 parts by mass, the handling property may be insufficient and the reliability of the capacitor may be lowered. If it exceeds 1 part by mass, the film is easily torn or falls off from the thin film, and insulation defects are likely to occur.

The olefin-based laminated film of the present invention preferably has a 1% shrinkage start temperature of 140 ° C. or higher as measured by TMA in the longitudinal direction of the film. It is more preferably 143 ° C. or higher, further preferably 145 ° C. or higher, and most preferably 148 ° C. or higher. The upper limit is not particularly limited, but is set to 160 ° C. The above measurement is carried out in the longitudinal direction under the condition that the temperature is raised from 25 ° C. to 160 ° C. by Thermal Mechanical Analysis (TMA) at a heating rate of 4 mm in width × 15 mm in measurement length and 0.15 MPa in tension and 5 ° C./min. Here, sampling is performed so that the measurement point is at the center of the measurement length of 15 mm. When the 1% shrinkage start temperature of TMA measurement in the longitudinal direction of the film is less than 140 ° C., the film itself tends to shrink when the capacitor manufacturing process and the usage process are in a high temperature environment, and it is resistant to poor contact with the metallikon at the end of the element. The voltage may be reduced, or the element may be wound tightly, causing a decrease in capacitance or short-circuit failure. In order to control the heat shrinkage within the above range, the configuration of two or more layers of A / B having at least one surface layer as the A layer, preferably the configuration of three or more layers of A / B / A, and the MFR are different. Use a cyclic olefin resin blend containing a cyclic olefin resin or an elastomer, or set the temperature of the heat treatment and relaxation treatment steps after biaxial stretching to be described later to 140 ° C or higher and the melting point of the polypropylene resin to -5 ° C or lower. This can be achieved by controlling the temperature.

The olefin-based laminated film of the present invention preferably has a coefficient of static friction (μs) of 0.3 or more and 1.5 or less when one surface of the film and the opposite surface are overlapped. The coefficient of static friction (μs) is more preferably 0.35 or more and 1.2 or less, still more preferably 0.4 or more and 1 or less, and most preferably 0.45 or more and 0.9 or less. If the coefficient of static friction (μs) at the time of superimposition is less than 0.3, the film may slip too much and winding may occur during film formation or element processing. If the coefficient of static friction (μs) exceeds 1.5, the slippage of the film is extremely reduced, the handling property is poor, wrinkles are likely to occur, and the element processability may be poor. In order to control the coefficient of static friction (μs) within the range, a configuration of two or more layers of A / B having at least one surface layer as the A layer, preferably a configuration of three or more layers of A / B / A, is used. This can be achieved by controlling conditions such as the resin composition constituting the A layer and the cooling temperature at the time of cooling and solidifying the molten sheet, which will be described later, within a preferable range.

The olefin-based laminated film of the present invention has a center line average roughness SRa on both surfaces from the viewpoints of uniformity of gaps between film layers, slipperiness between films or with a transport roll, and reliability as a capacitor. It is preferable that the average roughness SRz of both surfaces is 20 nm or more and the 10-point average roughness SRz of both surfaces is 200 nm or more, and more preferably the center line average roughness SRa of both surfaces is 40 nm or more and the 10-point average roughness of both surfaces. The SRz is 350 nm or more, more preferably the center line average roughness SRa of both surfaces is 60 nm or more, and the 10-point average roughness SRz of both surfaces is 500 nm or more. If the centerline average roughness SRa is less than 20 nm and the 10-point average roughness SRz is less than 200 nm, the slip of the film is extremely reduced, the handling property is poor, wrinkles are likely to occur, and the film is used continuously as a capacitor. The capacitance change may be large due to the influence of wrinkles, etc., or when a capacitor with laminated films is used, the self-healing function (self-healing) may be difficult to operate and the reliability of the capacitor may decrease because there is no appropriate gap between the films. be. Although the upper limit is not particularly limited, the center line average roughness SRa is 500 nm on both surfaces, and the 10-point average roughness SRz is 1,500 nm on both surfaces. In order to control the centerline average roughness SRa of the olefin-based laminated film of the present invention within a preferable range, for example, a configuration of two or more layers of A / B having at least one surface layer as the A layer, preferably A / The composition of three or more layers of B / A, the composition ratio of the particles contained in the A layer, the composition ratio of the blended resin of polypropylene and the resin thermoplastic resin that is incompatible with polypropylene, and the cooling temperature at the time of cooling and solidifying the molten sheet, etc. This can be achieved by controlling the conditions within a preferable range.

The olefin-based laminated film of the present invention preferably has a breaking elongation of 50% or more in the longitudinal direction of the film and a breaking strength of 50 MPa or more. The elongation at break in the longitudinal direction of the film is more preferably 75% or more, still more preferably 100% or more. The upper limit of the elongation at break is not particularly limited, but is set to 300%. The breaking strength of the film in the longitudinal direction is more preferably 60 MPa or more, still more preferably 75 MPa or more. If the breaking elongation in the longitudinal direction of the film is less than 50%, or if the breaking strength is less than 50 MPa, it breaks because it cannot withstand the stress during transportation in the vapor deposition process and element processing process when making a capacitor. May be done. In order to control the breaking elongation and breaking strength within the range, the above-mentioned structure of two or more layers of A / B having at least one surface layer as the A layer, preferably a structure of three or more layers of A / B / A, MFR Use a blend of cyclic olefin resins or cyclic olefin resins containing an elastomer, or perform biaxial stretching, which will be described later, and set the temperature of the heat treatment and relaxation treatment steps after stretching to 140 ° C or higher, polypropylene resin. This can be achieved by controlling the temperature at a melting point of −5 ° C. or lower.

Since the olefin-based laminated film of the present invention is excellent in transparency, slipperiness, and high-temperature characteristics, it is suitably used for general industrial applications and packaging applications. Of course, it is usually useful for general capacitors of 30 μm or less, but it is particularly suitable for thin-film heat-resistant film capacitors required for automobile applications (including hybrid car applications) used in high temperature environments. In particular, the film thickness is preferably in the range of 0.5 μm or more and less than 15 μm, more preferably 0.5 μm or more and 10 μm or less, and further preferably 0.8 μm or more and 5.0 μm or less. In order to control the thickness of the olefin-based laminated film of the present invention within the range, a configuration of two or more layers, preferably three or more layers of A / B / A, in which at least one of the surface layers is the A layer is coextruded. This can be achieved by laminating the films and applying biaxial stretching, which will be described later.

The olefin-based laminated film of the present invention is preferably used as a dielectric film for a capacitor, but is not limited to the type of capacitor. Specifically, from the viewpoint of electrode configuration, it may be either a foil-wound capacitor or a metal vapor-deposited film capacitor, and is preferably used for an oil-immersed capacitor impregnated with insulating oil or a dry capacitor that does not use insulating oil at all. Be done. Further, from the viewpoint of shape, it may be a winding type or a laminated type. However, due to the characteristics of the film of the present invention, it is particularly preferably used as a metal vapor deposition film capacitor.

Since the surface energy of an olefin-based laminated film is usually low and it is difficult to stably apply metal vapor deposition, it is preferable to perform surface treatment before vapor deposition for the purpose of improving metal adhesion. Specific examples of the surface treatment include corona discharge treatment, plasma treatment, glow treatment, and flame treatment. Normally, the wetting tension of the polypropylene resin film surface is about 30 mN / m, but by these surface treatments, the wetting tension can be set to about 37 to 50 mN / m, preferably about 39 to 48 mN / m. It is preferable because it has excellent adhesiveness and good safety.

The olefin-based laminated film of the present invention is obtained by biaxial stretching using a raw material capable of imparting the above-mentioned characteristics. As a biaxial stretching method, any of the inflation simultaneous biaxial stretching method, the tenter simultaneous biaxial stretching method, and the tenter sequential biaxial stretching method can be obtained. It is preferable to adopt the tenter sequential biaxial stretching method from the viewpoint of controlling the surface unevenness forming property.

Next, an example of the method for producing the olefin-based laminated film of the present invention will be described.

First, a laminated film of a cyclic olefin resin and a polypropylene resin is melt-extruded onto a support to obtain an olefin resin laminated sheet, and this laminated sheet is sequentially biaxially stretched by longitudinal stretching and lateral stretching, and then heat-treated and relaxed. To produce an olefin-based laminated film. Hereinafter, the description will be more specific, but the present invention is not necessarily limited to this.

First, a polypropylene resin raw material A having a mesopentad fraction of 0.95 or more and a melting point of more than 160 ° C. is supplied to a uniaxial extruder for the A layer, and a cyclic olefin resin raw material B is uniaxially extruded for the B layer. It is supplied to the machine and laminated in a three-layer structure of A layer / B layer / A layer by a feed block method by melt coextrusion at 200 to 260 ° C., or laminated in a two-layer structure of A layer / B layer. Two or more layers of laminated resin such as resin are extruded from a slit-shaped mouthpiece and solidified on a cooling drum (casting drum) controlled to a temperature of 20 to 100 ° C. to obtain an unstretched sheet. In the present invention, it is preferable to use a blended resin of cyclic olefin resins having different MFRs or a cyclic olefin resin containing an elastomer as the raw material for the B layer, which has suitable mechanical properties for a capacitor and dimensions in a high temperature region. It is preferable from the viewpoint of obtaining an olefin-based laminated film having stability and insulating performance. As the adhesion method to the casting drum, any of the electrostatic application method, the adhesion method using the surface tension of water, the air knife method, the press roll method, the underwater casting method and the like may be used. Here, in the case of a two-layer structure of A layer / B layer, the surface on the B layer side is smoothed by extruding the B layer of the molten laminated polymer from the slit-shaped mouthpiece so as to contact the casting drum surface. Can be done. It is also possible to laminate by coating or laminating instead of laminating by coextrusion. However, when a laminated structure without an adhesive layer is used for coating or laminating, the adhesive strength at the resin interface between the A layer and the B layer is insufficient, and the resin may be peeled off in the film deposition process or the capacitor processing process. Even if it is possible, the withstand voltage performance at high temperature may be deteriorated, or when the laminated structure is formed via an adhesive layer, the withstand voltage performance at high temperature may be deteriorated due to the influence of the adhesive. Therefore, the lamination is preferably performed by coextrusion.

Next, this unstretched sheet is biaxially stretched. First, the unstretched sheet is preheated by passing it through a roll kept at 60 to 160 ° C., and then the sheet is kept at a temperature of 60 to 160 ° C., stretched 1.5 to 10 times in the longitudinal direction, and then cooled to room temperature. Then, a longitudinally uniaxially stretched film is obtained. A more preferable stretching ratio in the longitudinal direction is 2 to 9 times, preferably 2.5 to 8 times. The stretching method and stretching ratio are not particularly limited and are appropriately selected depending on the characteristics of the polymer used.

Next, the longitudinally uniaxially stretched film is guided to a tenter, the end portion of the film is gripped with a clip, and the transverse stretch is stretched 5.1 to 15 times, more preferably 6 to 12 times in the width direction at a temperature of 140 to 175 ° C. .. When the draw ratio in the width direction is less than 5.1 times, the mechanical strength of the olefin-based laminated film in the width direction is lowered, and the thickness unevenness is deteriorated, so that the withstand voltage may be lowered. On the other hand, if the draw ratio in the width direction exceeds 15 times, the film may easily break and the productivity may decrease. In the present invention, when an unstretched sheet that is not biaxially stretched is used, the polypropylene resin of the A layer and the cyclic olefin resin of the B layer are peeled off, and the elongation at break is not sufficiently obtained. In the vapor deposition process and the element processing process of the above, it may not be able to withstand the stress during transportation and may break. Although biaxial stretching can be performed before laminating, biaxial stretching is preferable after laminating.

In the following heat treatment and relaxation treatment steps in the present invention, the heat treatment is performed at a temperature of 130 ° C. or higher and lower than the melting point of the polypropylene resin while giving 2 to 20% relaxation in the width direction while tension-grasping the width direction with a clip. However, it is preferable from the viewpoint of uniformly relaxing the in-plane of the film, reducing local structural unevenness, improving withstand voltage characteristics, and obtaining thermal dimensional stability. The heat treatment temperature in the heat treatment step is preferably 140 ° C. or higher and the melting point of the polypropylene resin −5 ° C. or lower, more preferably 145 ° C. or higher and the melting point of the polypropylene resin −10 ° C. or lower. If the heat treatment temperature is less than 130 ° C., thermal dimensional stability cannot be obtained, which may cause a decrease in capacity or short-circuit fracture in a high-temperature usage environment when a capacitor is used. On the other hand, if the heat treatment temperature exceeds the melting point of the polypropylene-based resin, film rupture may occur during film formation.

The relaxation rate in the relaxation treatment step is preferably 5 to 18%, more preferably 8 to 15%. If it exceeds 18%, the film may loosen too much inside the tenter and wrinkle the product, causing unevenness during vapor deposition. On the other hand, if the relaxation rate is less than 5%, thermal dimensional stability cannot be obtained and the capacitor It may cause a decrease in capacity or short-circuit destruction in a high-temperature usage environment.

After the above heat treatment and relaxation treatment steps, the film is guided to the outside of the tenter through a cooling step at 50 to 140 ° C. while being tensely gripped in the width direction with a clip, the clip at the end of the film is released, and the film is subjected to a winder step. Slit the edge and wind up the film product roll. Here, in order to improve the adhesiveness of the vapor-deposited metal on the surface to be vapor-deposited before winding the film, it is preferable to perform the corona discharge treatment in air, nitrogen, carbon dioxide gas, or a mixed gas thereof.

In the present invention, it is also preferable to provide a metal film on the surface of the above-mentioned olefin-based laminated film to form a metal film laminated film, but the method is not particularly limited. For example, a method in which aluminum is vapor-deposited on at least one surface of an olefin-based laminated film to provide a metal film such as an aluminum-deposited film as an internal electrode of a film capacitor is preferably used. At this time, other metal components such as nickel, copper, gold, silver, chromium and zinc can be vapor-deposited simultaneously or sequentially with aluminum. Further, a protective layer may be provided on the vapor-deposited film with oil or the like.

In the present invention, if necessary, after forming the metal film, the metal film laminated film can be annealed at a specific temperature or heat-treated. Further, for insulation or other purposes, at least one side of the metal film laminated film may be coated with polyphenylene oxide or the like.

The metal film laminated film thus obtained can be laminated or wound by various methods to obtain a film capacitor. An example of a preferred method for manufacturing a wound film capacitor is as follows.

Aluminum is vapor-deposited on one side of an olefin-based laminated film under reduced pressure. At that time, the film is deposited in a striped shape having a margin portion running in the longitudinal direction of the film. Next, a blade is inserted into the center of each vapor deposition portion and the center of each margin portion on the surface to slit the reel, and a tape-shaped take-up reel having a margin on one side of the surface is created. Two tape-shaped take-up reels with a left or right margin, one each for the left margin and one for the right margin, are overlapped and wound so that the vapor-deposited portion protrudes from the margin portion in the width direction. To get.

When vapor deposition is performed on both sides, vapor deposition is performed in a striped shape having a margin portion running in the longitudinal direction of one surface, and the other surface is striped so that the margin portion in the longitudinal direction is located in the center of the back surface side vapor deposition portion. Deposit in the form. Next, a blade is inserted in the center of each of the front and back margins to make a slit, and a tape-shaped take-up reel having a margin on one side of each side (for example, if there is a margin on the right side of the front surface, a margin on the left side on the back surface) is produced. Two reels and one undeposited laminated film are laminated and wound so that the metallized film protrudes from the laminated film in the width direction to obtain a wound body.

A wound film capacitor can be obtained by removing the core material from the wound body produced as described above, pressing the core material, spraying metallicon on both end surfaces to form an external electrode, and welding a lead wire to the metallicon. The applications of film capacitors are wide-ranging, such as for railway vehicles, automobiles (hybrid cars, electric vehicles), solar power generation / wind power generation, and general household appliances, and the film capacitors of the present invention are also suitable for these applications. Can be used. In addition, it can be used for various purposes such as packaging film, mold release film, process film, sanitary goods, agricultural goods, construction goods, and medical goods.

The method for measuring the characteristic value and the method for evaluating the effect in the present invention are as follows.

(1) Film thickness A total of 10 thicknesses of olefin-based laminated film at arbitrary locations are measured using a contact-type electronic micrometer (K-312A type) manufactured by Anritsu Co., Ltd. in an atmosphere of 23 ° C. and 65% RH. Then, the average value was taken as the film thickness of the olefin-based laminated film.

(2) Ratio of insulation breakdown voltage V (23) (V / μm) at 23 ° C to insulation breakdown voltage V (130) (V / μm) at 130 ° C, V (130) / V (23)
The dielectric breakdown voltage test according to the JIS C2330 (2001) 7.4.11.2 B method (flat plate electrode method) was performed 30 times in an atmosphere of 23 ° C. and 65% RH, and the obtained value was used as the film thickness (above). Divided by (1)) and converted to (V / μm), out of a total of 30 measured values (calculated values), 5 points from the largest breakdown voltage and 5 points from the smallest breakdown voltage were excluded 20 The average value of the points was defined as the film dielectric breakdown voltage V (23) at 23 ° C. Similarly, after heating the film for 1 minute in an oven kept at 130 ° C., dielectric breakdown according to JIS C2330 (2001) 7.4.11.2 B method (plate electrode method) in the atmosphere. The voltage test was performed 30 times, and the obtained value was divided by the film thickness ((1) above) and converted to (V / μm). Of the total 30 measured values (calculated values), the breakdown voltage was the highest. The average value of 20 points excluding 5 points from the largest and 5 points from the smallest was defined as the film dielectric breakdown voltage V (130) at 130 ° C. Using the obtained film breakdown voltage in the following equation, the ratio of the breakdown voltage V (23) (V / μm) at 23 ° C to the breakdown voltage V (130) (V / μm) at 130 ° C. The value of was calculated.
V (130) / V (23)
(3) Breaking elongation and breaking strength in the longitudinal direction of the film Five samples with a width of 10 mm and a length of 50 mm (measurement direction) were cut out from the olefin-based laminated film in the longitudinal direction, and marked at positions 15 mm from both ends. The trial length was 20 mm. Next, a rectangular sample was set in a tensile tester (Tencilon UCT-100 manufactured by Orientec) with an initial chuck distance of 20 mm, and a tensile test of the film was performed in an atmosphere of 23 ° C. at a tensile speed of 300 mm / min. The elongation (unit:%) and strength (unit: MPa) at the time when the film was broken were obtained. The measurement was performed 5 times in the longitudinal direction of the film, the average value was calculated, and the breaking elongation and breaking strength were determined.

(4) 1% shrinkage start temperature of TMA measurement In the present invention, the 1% shrinkage start temperature means the temperature when the shrinkage of the film reaches 1% in the following TMA measurement.

A sample having a width of 4 mm and a length of 50 mm (measurement direction) was cut out from the olefin-based laminated film in the longitudinal direction, and the film was sandwiched between metal chucks so as to have a trial length of 15 mm. Next, using Thermal Mechanical Analysys manufactured by Seiko Instruments Inc.; TMA / SS6000, the sample sandwiched between the chucks was set in the apparatus, and the shrinkage curve in the longitudinal direction of the film under a constant load was obtained by the following temperature program. From the obtained shrinkage curve, the temperature at which the film shrank by 1% was read.

Temperature program 25 ° C → (10 ° C / min) → 160 ° C (hold 5 min)
Load 0.3MPa.

(5) Coefficient of static friction (μs)
The measurement was carried out at 25 ° C. and 65% RH according to JIS K 7125 (1999) using a slip tester manufactured by Toyo Seiki Co., Ltd. The measurement was carried out in the longitudinal direction and on top of each other, that is, so that the front surface of one film and the back surface of the other film were in contact with each other. The same measurement was performed 5 times for each sample, and the average value of the obtained values was calculated and used as the coefficient of static friction (μs) of the sample.

(6) Mesopentad fraction The polypropylene of the film was extracted with n-heptane at 60 ° C. for 2 hours to remove impurities and additives in the polypropylene, and then dried under reduced pressure at 130 ° C. for 2 hours or more as a sample. The sample was dissolved in a solvent, and the mesopentad fraction (mm mm) was determined under the following conditions using ^{13 C-NMR.}

Measurement conditions / equipment: Bruker DRX-500
-Measurement nucleus: ¹³ C nucleus (resonance frequency: 125.8 MHz)
-Measured concentration: 10% by mass
-Solvent: Benzene: Di-dichlorobenzene = 1: 3 mixed solution (volume ratio)
・ Measurement temperature: 130 ℃
・ Spin rotation speed: 12Hz
・ NMR sample tube: 5 mm tube ・ Pulse width: 45 ° (4.5 μs)
・ Pulse repetition time: 10 seconds ・ Data point: 64K
・ Number of integrations: 10,000 times ・ Measurement mode: complete decoupling
The Fourier transform was performed with the analysis condition LB (line broadening factor) set to 1, and the mmmm peak was set to 21.86 ppm. Peak division is performed using WINFIT software (manufactured by Bruker). At that time, peak division is performed from the peak on the high magnetic field side as follows, and after performing automatic fitting of software and optimizing the peak division, mm mm and ss (spinning sideband peak of mm mm) Let the sum of the peak fractions of the above be the mesopentad fraction (mm mm).
(1) mrrm
(2) (3) rrrm (split as two peaks)
(4) rrrrr
(5) mrmm + rmrr
(6) mmrr
(7) mmml
(8) ss (mmmm spinning sideband peak)
(9) mmmm
(10) rmmr.

The same measurement was performed 5 times for the same sample, and the average value of the obtained mesopentad fractions was taken as the mesopentad fraction of the sample.

(7) Melting Point of Polypropylene Resin Using a differential scanning calorimeter (EXSTAR DSC6220 manufactured by Seiko Instruments Inc.), the temperature of 3 mg of polypropylene resin is raised from 30 ° C. to 260 ° C. at 40 ° C./min in a nitrogen atmosphere. Then, after holding at 260 ° C. for 5 min, the temperature is lowered to 30 ° C. under the condition of 40 ° C./min. Further, after holding the temperature at 30 ° C. for 5 min, the temperature is raised from 30 ° C. to 260 ° C. under the condition of 40 ° C./min. The peak temperature of the endothermic curve obtained at the time of this temperature rise was defined as the melting point of the polypropylene resin.

(8) Glass transition temperature of resin Using a differential scanning calorimeter (EXSTAR DSC6220 manufactured by Seiko Instruments Inc.), the temperature of 3 mg of resin is raised from 30 ° C. to 260 ° C. at 40 ° C./min in a nitrogen atmosphere. Then, after holding at 260 ° C. for 5 min, the temperature is lowered to 30 ° C. under the condition of 40 ° C./min. Further, after holding the temperature at 30 ° C. for 5 min, the temperature is raised from 30 ° C. to 260 ° C. under the condition of 40 ° C./min. The glass transition temperature obtained at the time of this temperature rise was calculated by the following formula.

Glass transition temperature = (extrapolation glass transition start temperature + extrapolation glass transition end temperature) / 2
Here, the extra glass transition start temperature is the intersection of the straight line extending the baseline on the low temperature side to the high temperature side and the tangent line drawn at the point where the slope of the curve of the stepwise change part of the glass transition is maximized. Let it be the temperature. The outer glass transition end temperature is the temperature at the intersection of the straight line extending the baseline on the high temperature side to the low temperature side and the tangent line drawn at the point where the slope of the curve of the stepwise change part of the glass transition is maximized. do.

(9) Melt flow rate (MFR)
The MFR of the polypropylene resin was measured according to the condition M (230 ° C., 2.16 kg) of JIS K 7210 (1999). The MFR of the cyclic olefin resin was measured according to the condition M (260 ° C., 2.16 kg) of JIS K 7210 (1999).

(10) Capacitor element workability and capacitor characteristics in an atmosphere of 130 ° C. Aluminum film resistance is 8Ω / A vapor deposition pattern having a so-called T-shaped margin pattern in which a margin portion was provided in a direction perpendicular to the longitudinal direction was applied by sq to obtain a vapor deposition reel having a width of 50 mm.

Next, using this reel, the capacitor element is wound by a device winding machine (KAW-4NHB) manufactured by Minato Seisakusho, metallikon is applied, and then heat treatment is performed at a temperature of 140 ° C. for 10 hours under reduced pressure to wire the lead wire. Finished the mounting capacitor element.

Using the 10 capacitor elements thus obtained, a voltage of 200 VDC is applied to the capacitor elements at a high temperature of 130 ° C., and after 10 minutes have passed at the voltage, the voltage is gradually applied at a boost rate of 50 VDC / 1 minute in steps of 50 VDC. A so-called step-up test was performed in which the voltage was repeatedly increased. The holding time was set to 10 minutes in each step.

<Capacitor element workability>
A capacitor element was prepared in the same manner as above, and the shape of the element was visually confirmed. Judgment was made based on the following criteria.
⊚: There is no deviation or deformation of the capacitor element film, and there is no problem in the subsequent process. ○: There is some deviation or deformation of the capacitor element film, but there is no problem in the later process. Levels ◎ and ○, which have large deviations and deformations and interfere with subsequent processes, can be used. It is difficult to put it into practical use with ×.

<Withstand voltage>
The change in capacitance at this time is measured and plotted on a graph, and the voltage at which the capacitance is 70% of the initial value is divided by the thickness of the film ((1) above) to obtain a withstand voltage evaluation. Evaluated as per.
⊚: 320V / μm or more ◯: 300V / μm or more and less than 320V / μm Δ: 280V / μm or more and less than 300V / μm ×: 280V / μm or less ◎, ◯, Δ can be used. X is inferior in practical performance.

<Reliability>
After increasing the voltage until the capacitance decreased to 10% or less of the initial value, the capacitor element was disassembled and the state of failure was examined, and the reliability was evaluated as follows.
⊚: No change in element shape and no penetrating fracture is observed. ○: No change in element shape and penetrating fracture within 10 layers of film is observed. Δ: Change in element shape is observed or penetration of more than 10 layers. State fracture is observed ×: The element shape is destroyed ◎ and ○ can be used without problems, and Δ can be used depending on the conditions. X is inferior in practical performance.

Hereinafter, the effects of the present invention will be further described with reference to examples.

(Example 1)
Prime Polymer Co., Ltd. polypropylene resin with mesopentad fraction of 0.98, melting point of 167 ° C., and melt flow rate (MFR) of 2.6 g / 10 minutes, and Basell polypropylene resin (high melt tension polypropylene Profax (high melt tension polypropylene Profax) PF-814) (trademark) was blended in an amount of 1.0% by mass and supplied to a single-screw melt extruder A for layer A at a temperature of 260 ° C. As the cyclic olefin resin (B1), Polyplastics "TOPAS" (registered trademark) 6015S-04 (a resin obtained by copolymerizing ethylene and norbornene, having a glass transition temperature of 158 ° C. and a melt flow rate (MFR)). 3.6 g / 10 min)) is 74.7 parts by mass, and the cyclic olefin resin (B2) is made of Polyplastics "TOPAS" (registered trademark) 8007F-04 (a resin obtained by copolymerizing ethylene and norbornene). , Glass transition temperature is 158 ° C, melt flow rate (MFR) is 28.8 g / 10 minutes)) 25 parts by mass, and 0.3 mass of Irganox® 1010 manufactured by Ciba Specialty Chemicals, which is an antioxidant. Each part was mixed and supplied to a single-screw melt extruder B for the B layer having a temperature of 260 ° C. Melt extrusion is performed with an A-layer and B-layer extruder, foreign matter is removed with an 80 μm-cut sintering filter, and then a feed block is used to laminate A / B / A in three layers with a stacking thickness ratio of 1/1/1. (The total ratio of both surface layers A to the total thickness of the film is 66.7%), the extrusion amount is adjusted, the molten laminated polymer is discharged from the T die, and the molten sheet is held at 70 ° C. for casting. An unstretched sheet was obtained by contacting and cooling and solidifying on a drum by applying electrostatic force. Next, the sheet was gradually preheated to 146 ° C. in a plurality of roll groups, subsequently kept at a temperature of 146 ° C., passed between rolls provided with a peripheral speed difference, and stretched 3.3 times in the longitudinal direction. Subsequently, the film was led to a tenter, stretched 10.5 times in the width direction at a temperature of 167 ° C., and then heat-treated at 150 ° C. while giving 10% relaxation in the width direction as a heat treatment and a relaxation treatment, and further, the width was cut with a clip. While holding the direction, guide it to the outside of the tenter through a cooling process at 100 ° C., release the clip at the end of the film, and then put it on the film surface (casting drum contact surface side) in the air with a processing strength of ^{25 W · min / m 2.} A corona discharge treatment was performed, and a film having a film thickness of 3.5 μm was wound as a film roll. As shown in Table 1, the characteristics and capacitor characteristics of the olefin-based laminated film of this example were at extremely excellent levels in terms of device workability, withstand voltage, and reliability.

(Example 2)
As the cyclic olefin resin (B1), Polyplastics "TOPAS" (registered trademark) 6013F-04 (a resin obtained by copolymerizing ethylene and norbornene, having a glass transition temperature of 138 ° C. and a melt flow rate (MFR). 12.6 g / 10 minutes)) as 89.7 parts by mass, cyclic olefin resin (B2), Polyplastics "TOPAS" (registered trademark) 9903D10 (resin obtained by copolymerizing ethylene and norbornene, and glass. Transition temperature is 33 ° C., melt flow rate (MFR) is 7.2 g / 10 minutes)) by 10 parts by mass, and Irganox® 1010 manufactured by Ciba Specialty Chemicals, which is an antioxidant, is 0.3 parts by mass, respectively. An olefin-based laminated film was obtained in the same manner as in Example 1 except that the mixture was mixed and a film was formed under the conditions shown in Table 1. As shown in Table 1, the characteristics and capacitor characteristics of the olefin-based laminated film of this example were at extremely excellent levels in terms of device workability, withstand voltage, and reliability.

(Example 3)
The mixing ratio of the cyclic olefin resins (B1) and (B2) was changed to 59.7 parts by mass and 40 parts by mass, and the plurality of roll groups for stretching the unstretched sheet in the longitudinal direction and the temperature at the time of stretching were set to 134 ° C. An olefin-based laminated film was obtained in the same manner as in Example 1 except that the stretching temperature in the width direction in the tenter was changed to 162 ° C. and the film was formed under the conditions shown in Table 1. The characteristics and capacitor characteristics of the olefin-based laminated film of this example are as shown in Table 1, and the element processability is very excellent, and both the withstand voltage and the reliability are at a level where there is no problem in actual use.

(Example 4)
An olefin-based laminated film was obtained in the same manner as in Example 1 except that the draw ratios in the longitudinal direction and the width direction were lowered and the film was formed under the conditions shown in Table 1. As shown in Table 1, the characteristics and capacitor characteristics of the olefin-based laminated film of this example were such that there was no problem in actual use in both capacitor element workability and withstand voltage, and the reliability was extremely excellent.

(Example 5)
As a polypropylene resin for layer A, 98 parts by mass of polypropylene resin manufactured by Prime Polymer Co., Ltd., which has a mesopentad fraction of 0.98, a melting point of 167 ° C, and a melt flow rate (MFR) of 2.6 g / 10 minutes, Mitsui Kagaku "TPX" (registered trademark) MX002 (polymethylpentene resin with a melting point of 224 ° C) is blended in a blending ratio of 2 parts by mass, kneaded and extruded with an extruder set at 240 ° C, and the strands are water-cooled and then chipped. , A polypropylene resin raw material was supplied to a single-screw melt extruder for layer A, and an olefin-based laminated film was obtained in the same manner as in Example 1 except that a film was formed under the conditions shown in Table 1. As shown in Table 1, the characteristics and capacitor characteristics of the olefin-based laminated film of this example were at extremely excellent levels in terms of device workability, withstand voltage, and reliability.

(Example 6)
As a cyclic olefin resin, 99.7 parts by mass of Polyplastics "TOPAS" (registered trademark) 6013F-04 (resin obtained by copolymerizing ethylene and norbornene with a glass transition temperature of 138 ° C.) and antioxidant An olefin-based laminated film was obtained in the same manner as in Example 1 except that Irganox (registered trademark) 1010 manufactured by Ciba Specialty Chemicals, which was an agent, was formed in an amount of 0.3 parts by mass under the conditions shown in Table 1. .. The characteristics and capacitor characteristics of the olefin-based laminated film of this example are as shown in Table 1, and both the element processability and the withstand voltage are very excellent, and the reliability is also excellent.

(Example 7)
As a cyclic olefin resin for the B layer, 95.7 parts by mass of Polyplastics "TOPAS" (registered trademark) 6013F-04 (a resin obtained by copolymerizing ethylene and norbornene and having a glass transition temperature of 138 ° C.). , 4 parts by mass of (Kraton MD1537: SEBS, manufactured by Kraton Polymer Co., Ltd.) as a styrene-based elastomer, and IRGANOX1010 manufactured by Ciba Specialty Chemicals, which is an antioxidant, blended in a blending ratio of 0.3 parts by mass and set at 270 ° C. The strands were kneaded and extruded with the above-mentioned extruder, and the strands were water-cooled and then chipped. 99.7 parts by mass of this chipped cyclic olefin resin and 0.3 parts by mass of Irganox® 1010 manufactured by Ciba Specialty Chemicals, which is an antioxidant, are used as a single-screw melt extruder for the B layer. An olefin-based laminated film was obtained in the same manner as in Example 1 except that the film was formed under the conditions shown in Table 1. As shown in Table 1, the characteristics and capacitor characteristics of the olefin-based laminated film of this example were at extremely excellent levels in terms of device workability, withstand voltage, and reliability.

(Example 8)
As a polypropylene resin for layer A, with respect to 100 parts by mass of a polypropylene resin manufactured by Prime Polymer Co., Ltd., which has a mesopentad fraction of 0.98, a melting point of 167 ° C., and a melt flow rate (MFR) of 2.6 g / 10 minutes. 0.2 parts by mass of "Electrochemical Industry Co., Ltd. average particle diameter 0.3 μm silica particles: SFP-20MHE (silane coupling surface treatment)", "Tokuyama Co., Ltd. average particle diameter 0.1 μm silica particles: Sunseal SSP -M01 "was kneaded and extruded with an extruder set at 240 ° C. so as to be 1.2 parts by mass, and the strands were water-cooled and then chipped to be used as a polypropylene resin raw material and supplied to a single-screw melt extruder for layer A. An olefin-based laminated film was obtained in the same manner as in Example 1 except that the film was formed under the conditions shown in Table 1. The characteristics and capacitor characteristics of the olefin-based laminated film of this example are as shown in Table 1, and although the processing suitability, withstand voltage, and reliability of the capacitor element are inferior, they are at a level that does not pose a problem in actual use.

(Example 9)
An olefin-based laminated film was obtained in the same manner as in Example 1 except that the temperature and relaxation treatment rate of the heat treatment and relaxation treatment after biaxial stretching were formed under the conditions shown in Table 1. The characteristics and capacitor characteristics of the olefin-based laminated film of this example are as shown in Table 1, and the processing suitability of the capacitor element is very excellent, and the withstand voltage and reliability are inferior, but they are at a level that does not pose a problem in actual use. rice field.

(Example 10)
Olefin in the same manner as in Example 1 except that the lamination thickness ratio and film forming conditions (longitudinal stretching ratio, lateral stretching ratio, heat treatment temperature) were changed to the conditions shown in Table 1 in the three-layer lamination of A / B / A. A system laminated film was obtained. The characteristics and capacitor characteristics of the olefin-based laminated film of this example are as shown in Table 1, and the capacitor element workability, withstand voltage, and reliability are all at excellent levels.

(Comparative Example 1)
As a polypropylene resin, a polypropylene resin manufactured by Prime Polymer Co., Ltd., which has a mesopentad fraction of 0.98, a melting point of 167 ° C., and a melt flow rate (MFR) of 2.6 g / 10 minutes, has a single film structure and is shown in Table 2. An olefin-based single film was obtained in the same manner as in Example 1 except that the film was formed under the above conditions. The characteristics and capacitor characteristics of the olefin-based single-film film of this comparative example are as shown in Table 2, and although the device workability is excellent, both the withstand voltage and reliability are extremely inferior, which causes problems in actual use. rice field.

(Comparative Example 2)
As the COC of the cyclic olefin resin, 99.7 parts by mass of a resin blended with the same composition as in Example 1, and 0.3 parts by mass of Irganox (registered trademark) 1010 manufactured by Ciba Specialty Chemicals, which is an antioxidant, are used. A film was formed in the same manner as in Example 1 except that the film was mixed to form a single film structure under the conditions shown in Table 2, but a film could not be obtained due to frequent tearing.

(Comparative Example 3)
An olefin-based laminated film was obtained in the same manner as in Example 1 except that the film was formed under the conditions shown in Table 2 without heat treatment and relaxation treatment. As shown in Table 2, the characteristics of the olefin-based film and the capacitor characteristics of this comparative example were extremely inferior in device workability, slightly inferior in withstand voltage and reliability, and were at a level that caused problems in actual use.

(Comparative Example 4)
An unstretched film (thickness 10 μm) having three layers of A / B / A was obtained in the same manner as in Example 1 except that biaxial stretching, heat treatment, and relaxation treatment were not performed. Table 2 shows the characteristics of the olefin-based laminated film and the capacitor characteristics of this comparative example. When the elongation at break is measured, the A layer and the B layer are peeled off and cannot be measured as a laminated film. However, it was a little inferior, and the withstand voltage and reliability were very inferior, and it was at a level that caused problems in actual use.

(Comparative Example 5)
The mixing ratio of the cyclic olefin resin was changed as shown in Table 2, the multiple roll groups for stretching the unstretched sheet in the longitudinal direction and the temperature during stretching were set to 140 ° C, and the stretching temperature in the width direction in the tenter was set to 160 ° C. An olefin-based laminated film was obtained in the same manner as in Example 1 except that the film-forming conditions were changed and the film-forming conditions were as shown in Table 2. The characteristics of the olefin-based laminated film and the capacitor characteristics of this comparative example are as shown in Table 2, and although the element processability is excellent, both the withstand voltage and reliability are extremely inferior, and they are at a level that causes problems in actual use. ..

(Comparative Example 6)
The film was produced in the same manner as in Example 1 except that the layered thickness ratio and the film forming conditions (longitudinal stretching ratio, lateral stretching ratio, heat treatment temperature) were formed by the three-layer lamination of A / B / A under the conditions shown in Table 2. The film was formed, but the film could not be obtained due to frequent tearing.

The olefin-based laminated film of the present invention can be applied to various applications such as packaging applications, tape applications, electric applications such as cable wrapping and capacitors, and especially for high voltage applications that require withstand voltage and reliability at high temperatures. Can be used for capacitor applications.

Claims (9)

Base layer part containing a cyclic olefin-based resin constituting layer containing a polypropylene-based resin on both surfaces of the layer (B layer) (A layer) is laminated, the dielectric breakdown voltage V (23) at 23 ℃ (V / μm) and 130 ° C. An olefin-based laminated film characterized in that the insulation breakdown voltage V (130) (V / μm) in the above satisfies the following equation (1).
V (130) / V (23) ≧ 0.6 ・ ・ ・ (1) The olefin-based laminated film according to claim 1, wherein the 1% shrinkage start temperature measured by TMA in the longitudinal direction is 140 ° C. or higher. The olefin-based laminated film according to claim 1, wherein the coefficient of static friction (μs) when one surface of the film and the opposite surface are overlapped is 0.3 or more and 1.5 or less. The olefin-based laminated film according to claim 1 or 2, wherein the breaking elongation in the longitudinal direction of the film is 50% or more and the breaking strength is 50 MPa or more. And a meso pentad fraction of the polypropylene resin is 0.95 or more and a melting point of higher than 160 ° C., olefin-based laminate film according to claim 1. The olefin-based laminated film according to any one of claims 1 to 5 , wherein the olefin-based laminated film is laminated by coextrusion. The olefin-based laminated film according to any one of claims 1 to 6 , wherein the olefin-based laminated film is biaxially stretched after being laminated. A metal film laminated film in which a metal film is provided on at least one side of the olefin-based laminated film according to any one of claims 1 to 7. A film capacitor using the metal film laminated film according to claim 8.