Polyolefin-based films, laminates, packaging materials and bales

Abstract

The present application provides a polyolefin-based film having excellent structural stability against heat during vapor deposition, and good water vapor barrier and oxygen barrier properties against heat during heat sterilization treatment, for example, for packaging applications. The polyolefin-based film is characterized in that when the storage modulus of the main orientation axis direction at 50°C and 121°C obtained from dynamic viscoelasticity measurement at a frequency of 10 Hz are set as E'50 (Pa) and E'121 (Pa), respectively, E'121 / E'50 exceeds 0.25 and is 0.99 or less, the thermal shrinkage at 150°C in the main orientation axis direction is 2% or more and 10% or less, the tensile elongation in the direction orthogonal to the main orientation axis is 20% or more and 300% or less, and at least one layer (A layer) comprising a cyclic olefin-based resin and a polypropylene-based resin.

Description

Technical Field

[0001] This invention relates to polyolefin films, laminates, packaging materials and bundles that are particularly suitable for packaging applications. Background Technology

[0002] Due to its excellent transparency, mechanical properties, and electrical properties, polypropylene film is used in various applications, including packaging, tapes, cable packaging, and electrical insulation (such as capacitors). In packaging, laminated films formed by depositing a thin film of aluminum (hereinafter sometimes referred to as "Al") onto a polypropylene film have become widely used. However, films obtained through Al deposition are opaque, making them unsuitable for applications requiring visibility of the contents. Furthermore, while there has been active effort to recycle packaging plastics in recent years, films containing Al deposition layers also suffer from insufficient recyclability.

[0003] Given the aforementioned situation, there is a growing trend to replace conventional Al vapor-deposited layers with transparent vapor-deposited layers such as alumina (hereinafter, sometimes referred to as AlOx) or silicon oxide. Using these transparent vapor-deposited layers can improve the transparency and recyclability of packaging materials. However, transparent vapor-deposited layers are typically thinner and more brittle than Al vapor-deposited layers. Therefore, defects such as pinholes and cracks can occur within the vapor-deposited layer during its formation or in subsequent processes such as bag manufacturing, resulting in compromised water vapor and oxygen barrier properties. Furthermore, when polypropylene film is used for food packaging, heat sterilization treatments (boiling, semi-boiling, retorting, etc.) are sometimes performed. However, compared to polyester films, polypropylene films generally have poorer thermal dimensional stability. Therefore, the heat during heat sterilization can cause film deformation, resulting in defects such as pinholes and cracks within the vapor-deposited layer, again leading to compromised water vapor and oxygen barrier properties.

[0004] As a film that improves the thermal dimensional stability of polypropylene film, it has been proposed to produce a laminated film by blending a cyclic olefin resin with a glass transition temperature of 120-170°C and polypropylene, and then providing polypropylene layers on both sides of the cyclic olefin resin layer. This improves heat resistance and makes it suitable for capacitor films that can exhibit voltage resistance even at high temperatures (Patent Documents 1, 2). Similarly, it has been proposed to provide polypropylene layers on both sides of a resin layer made by blending cyclic olefin resin and polypropylene, thereby providing high barrier properties, easy-to-process strength, and transparency suitable for packaging material applications (Patent Documents 3, 4).

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Publication No. 2020-521867

[0008] Patent Document 2: Japanese Patent Application Publication No. 2018-34510

[0009] Patent Document 3: Japanese Patent Application Publication No. 9-272188

[0010] Patent Document 4: Japanese Patent Publication No. 2005-535481 Summary of the Invention

[0011] The problem that the invention aims to solve

[0012] However, the polypropylene film described in Patent Document 1 improves heat resistance by blending cyclic olefin resins with polypropylene resin, but the area stretching ratio during film formation is small, and the molecular chain elongation of the polypropylene resin is insufficient, resulting in thermal stability that needs further improvement. Furthermore, the film in Patent Document 2 uses cyclic olefin monomers as the inner layer; therefore, like the polypropylene film described in Patent Document 1, it suffers from a small area stretching ratio during film formation, insufficient molecular chain elongation of the polypropylene resin, and thermal stability that also needs improvement.

[0013] Patent Document 3, suitable for packaging applications, describes a film made by blending cyclic olefin resins and polypropylene resins and then biaxially stretching them. However, the cyclic olefin resins in the film suffer from insufficient thermal fixation after dispersion and stretching, resulting in poor thermal dimensional stability. Patent Document 4 describes a film made by blending cyclic olefin resins and polypropylene resins, but it lacks the concept of stretching, leading to insufficient thermal stability. Therefore, the films in Patent Documents 3 and 4 have the following problems: the films deform due to the heat during heat sterilization, which easily generates defects such as pinholes and cracks in the vapor-deposited layer, reducing water vapor barrier properties and oxygen barrier properties.

[0014] Therefore, the objective of this invention is to provide a polyolefin membrane that can mitigate the reduction in structural stability, water vapor barrier properties, and oxygen barrier properties associated with heating.

[0015] Problem-solving methods

[0016] To address the aforementioned issues, the inventors conducted repeated and in-depth research, resulting in the invention of the first polyolefin film and the second polyolefin film of the present invention. The first polyolefin film of the present invention is characterized in that, when the storage modulus along the main orientation axis at 50°C and 121°C, obtained by dynamic viscoelasticity measurement at a frequency of 10 Hz, is set to E'50 (Pa) and E'121 (Pa), respectively, E'121 / E'50 exceeds 0.25 and is less than 0.99; the thermal shrinkage rate along the main orientation axis at 150°C is -2% or more and less than 10%; the tensile elongation rate in the direction orthogonal to the main orientation axis is 20% or more and less than 300%; and it has at least one layer (layer A) comprising a cyclic olefin resin and a polypropylene resin.

[0017] The second polyolefin membrane of the present invention has at least one layer (layer A) comprising a cyclic olefin resin and a polypropylene resin. When the cross section of layer A is defined as cross section X by cutting it with a plane parallel to the main orientation axis and the thickness direction, there are two or more regions of the cyclic olefin resin passing through the pair of short sides in a 1μm×2μm rectangle defined in cross section X with a pair of short sides parallel to the thickness direction. When the storage modulus in the main orientation axis direction at 50°C and 121°C, obtained by dynamic viscoelasticity measurement at a frequency of 10Hz, is set as E'50 (Pa) and E'121 (Pa), respectively, E'121 / E'50 exceeds 0.20 and is less than 0.99.

[0018] Invention Effects

[0019] According to the present invention, a polyolefin membrane can be obtained that can mitigate the reduction in structural stability, water vapor barrier and oxygen barrier properties associated with heating. Attached Figure Description

[0020] Figure 1 This is a schematic diagram showing a 1μm × 2μm rectangle in cross section X of a polyolefin film according to an embodiment of the present invention, defined with a pair of sides parallel to the thickness direction, and a region of cyclic olefin resin passing through the pair of sides of the rectangle parallel to the thickness direction.

[0021] Figure 2 This is a magnified photograph (2,000x magnification) of the cross section X of a polyolefin film according to one embodiment of the present invention (the schemes of Example 1 and Example 2). Detailed Implementation

[0022] The first and second polyolefin films of the present invention will now be described in detail. Regarding the preferred ranges, the combination of the upper and lower limits described below can be arbitrary. Furthermore, the first and second polyolefin films of the present invention are sometimes collectively referred to as the present invention or the polyolefin films of the present invention.

[0023] In addition, in this specification, polyolefin membranes are sometimes simply referred to as membranes. Furthermore, in the polyolefin membranes of the present invention, "thickness direction" refers to the direction perpendicular to the membrane surface. "Length direction" refers to the direction corresponding to the flow direction in the membrane manufacturing process (hereinafter, sometimes referred to as "MD"), and "width direction" refers to the direction orthogonal to the flow direction in the membrane manufacturing process within the membrane surface (hereinafter, sometimes referred to as "TD"). When the membrane sample is in the shape of a roll, roller, etc., the membrane winding direction can be considered the length direction.

[0024] It should be noted that the polyolefin membrane of the present invention is not a microporous membrane, and therefore does not have a large number of pores. That is, the polyolefin membrane of the present invention refers to polyolefin membranes other than microporous membranes. Here, a microporous membrane is defined as a membrane having a pore structure that extends through both surfaces of the membrane, and having an air permeability of less than 5000 seconds / 100ml using a Type B Gley tester according to JIS P 8117 (1998) at 23°C and 65% relative humidity, measured by a permeability time of 100ml of air.

[0025] Furthermore, a polyolefin membrane refers to a sheet-like molded body containing more than 50% but less than 100% by mass of polyolefin resin when all components constituting the membrane are considered as 100% by mass. It should be noted that when multiple polyolefin resins are included, the polyolefin resin content is calculated by summing all the polyolefin resins.

[0026] Polyolefin resins refer to resins that contain more than 50 mol% but less than 100 mol% of olefin units when all structural units constituting the resin are considered as 100 mol%. It should be noted that when multiple structural units equivalent to olefin units are included, all olefin units are summed up as the olefin unit content.

[0027] Polypropylene resins refer to resins that, when all structural units constituting the resin are considered as 100 mol%, contain more than 50 mol% and less than 100 mol% propylene units, and are not cyclic olefin resins.

[0028] Cyclic olefin resins refer to resins that, when all structural units constituting the resin are considered as 100 mol%, contain more than 10 mol% but less than 100 mol% of cyclic olefin units. It should be noted that, in cases where multiple structural units equivalent to cyclic olefin units are included, all cyclic olefin units are summed up as the amount of cyclic olefin units.

[0029] In the first polyolefin film of the present invention, considering thermal stability, when the storage modulus along the main orientation axis at 50°C and 121°C, obtained by dynamic viscoelasticity measurement at a frequency of 10 Hz, is set to E'50 (Pa) and E'121 (Pa), respectively, it is important that E'121 / E'50 exceeds 0.25 and is less than 0.99. It should be noted that the method for measuring the storage modulus along the main orientation axis is as described below.

[0030] A polyolefin film with an E'121 / E'50 greater than 0.25 indicates low temperature dependence of its storage modulus; in other words, it means that the amorphous molecular chains within the film are difficult to move at high temperatures. By making the polyolefin film's E'121 / E'50 greater than 0.25, for example, by depositing a layer (hereinafter referred to as the D layer) containing a total of more than 50% by mass and less than 100% by mass of metals and inorganic compounds on at least one surface of the film described later, it is possible to suppress film deformation caused by heat during deposition and defects such as pinholes and cracks generated in the D layer, resulting in good water vapor barrier and oxygen barrier properties of the laminate with the D layer. In addition, it can also suppress film deformation caused by high-temperature treatments such as heat sterilization after bag making, thus mitigating the reduction in water vapor barrier and oxygen barrier properties associated with such treatments. On the other hand, when the film's E'121 / E'50 exceeds 0.99, poor productivity issues such as film breakage sometimes occur during film making. This is because it requires the use of raw materials with high crystallinity and the implementation of biaxial stretching with a high area ratio during film formation.

[0031] Considering the above aspects, the E'121 / E'50 of the membrane is preferably 0.28 or more, more preferably 0.31 or more, even more preferably 0.33 or more, and particularly preferably 0.35 or more. On the other hand, the upper limit of E'121 / E'50 is preferably 0.89, more preferably 0.69.

[0032] Furthermore, regarding the thermal stability of the second polyolefin membrane of the present invention, when the storage modulus along the main orientation axis at 50°C and 121°C, obtained from dynamic viscoelasticity measurements at a frequency of 10 Hz, is set to E'50 (Pa) and E'121 (Pa), respectively, it is important that E'121 / E'50 exceeds 0.20 and is less than 0.99. Preferably, the E'121 / E'50 of the membrane is greater than 0.25, more preferably 0.28 or more, further preferably 0.31 or more, even more preferably 0.33 or more, and particularly preferably 0.35 or more. On the other hand, the upper limit of E'121 / E'50 is preferably 0.89, more preferably 0.69.

[0033] To control the E'121 / E'50 of the first polyolefin film of the present invention to be greater than 0.25 and less than 0.99, and to control the E'121 / E'50 of the second polyolefin film of the present invention to be greater than 0.20 and less than 0.99, for example, a method for controlling the regional structure (island structure) of the A layer can be used. More specifically, as the raw material for the A layer, it is effective to prepare a composite resin raw material by premixing a cyclic olefin resin and a polypropylene resin, to melt-extrude and sheet the material while controlling the content of the cyclic olefin resin, and to make the preheating temperature before stretching in the width direction of biaxial stretching 5°C to 15°C higher than the stretching temperature in the width direction while making the area stretching ratio 36.0 times or more (preferably 40.0 times or more).

[0034] It should be noted that, as an effect of pre-preparing the aforementioned composite resin raw material, an improved tensile strength can be expected. This is because, compared to mixing only the resin during film formation, the two resins can be mixed more uniformly, resulting in the island component resin being micro-dispersed in the sea component resin. Furthermore, when the composite resin raw material, pre-mixed using a twin-screw extruder with a high concentration of cyclic olefin resins, is used as a masterbatch for dilution, the dispersibility of the cyclic olefin resins is higher, which is therefore preferable.

[0035] The reason why E'121 / E'50 can be adjusted to the preferred range by the above method is believed to be that in the A layer, the resin peeling at the island interface of the island structure, which regards polypropylene resin as sea and cyclic olefin resin as island, is suppressed, and the island structure becomes smaller or thinner. As a result, the mobility of amorphous chains in the film can be suppressed through the synergistic effect of the high thermal stability of cyclic olefin resin and the excellent tensile properties of polypropylene resin.

[0036] It is important that the thermal shrinkage rate of the first polyolefin film of the present invention in the main orientation axis direction at 150°C is -2% or more and 10% or less. By ensuring that the film meets the above conditions, for example, when laminating the D layer (described later) by vapor deposition, defects such as pinholes and cracks in the D layer caused by film shrinkage due to heat during vapor deposition can be suppressed, resulting in good water vapor barrier and oxygen barrier properties of the laminated body containing the D layer. Furthermore, when high-temperature treatments such as heat sterilization are performed after bag making, film shrinkage can also be suppressed, preventing damage to water vapor barrier and oxygen barrier properties. Considering the above aspects, the upper limit of the thermal shrinkage rate in the main orientation axis direction at 150°C is preferably 8%, more preferably 6%, and even more preferably 4%. On the other hand, the lower limit of the thermal shrinkage rate in the main orientation axis direction at 150°C is preferably -1%. It should be noted that the thermal shrinkage rate in the main orientation axis direction at 150°C can be measured by the method described later.

[0037] In this invention, the principal orientation axis refers to the direction in which molecules are most strongly oriented within the surface of the polyolefin film. Typically, in the manufacture of polyolefin films, biaxial stretching is performed along both the length and width directions; however, the direction with the larger stretch ratio usually becomes the principal orientation axis. When the stretching direction (length and width directions) can be determined but the stretch ratio is unknown, the maximum load until fracture can be measured in the tensile test described later, and the direction with the larger measured value can be taken as the principal orientation axis.

[0038] As mentioned above, if the stretching direction and stretch ratio are known, the main orientation axis direction can be easily determined. However, in the case of films with unknown orientation axes, the main orientation axis direction can be determined using the following method. Specifically, prepare the film with any orientation upwards, and cut it into a rectangle with a length of 150 mm and a width of 10 mm as sample <1>. Define the direction of the long side of sample <1> as 0°. Next, collect sample <2> of the same size with the long side direction rotated 15° to the right from the 0° direction. Similarly, the long side direction of the rectangular sample is rotated 15° each time, and samples are collected in the same manner. <3> ~ <12> Next, for each rectangular sample, the maximum load until fracture is measured in the tensile test described later, and the direction of the maximum measured value is taken as the principal orientation axis direction.

[0039] In cases where a sample with a length of 150 mm and a width of 10 mm is unavailable, thus preventing the implementation of the tensile test described later, the crystal orientation of the α crystal (110) plane based on wide-angle X-rays is determined as follows, and the principal orientation axis direction is determined based on the following criteria. Specifically, X-rays (CuKα rays) are incident perpendicularly to the film surface, and the crystal peaks in the 2θ = approximately 14° (α crystal (110) plane) are scanned in the circumferential direction. The direction with the highest diffraction intensity in the obtained diffraction intensity distribution is taken as the principal orientation axis direction.

[0040] There are no particular limitations on the method for ensuring that the thermal shrinkage rate of the film in the main orientation axis direction at 150°C is between -2% and 10%. For example, it is effective to prepare a composite resin raw material made by premixing cyclic olefin resin and polypropylene resin as the raw material for the A layer, to melt-extrude and sheet the film while controlling the content of cyclic olefin resin, and to make the area stretching ratio in biaxial stretching 36.0 times or more (preferably 40.0 times or more) higher than the stretching temperature in the width direction by 5°C or more and 15°C or less.

[0041] In the first polyolefin film of the present invention, it is important that the elongation at break in the direction orthogonal to the main orientation axis is 20% or more and 300% or less. Here, the direction orthogonal to the main orientation axis refers to the direction orthogonal to the main orientation axis direction within the film surface. If the elongation at break in the direction orthogonal to the main orientation axis is 20% or more, it is particularly effective in suppressing the tension that may occur during vapor deposition and conveying when used for packaging purposes. Furthermore, it is also effective in suppressing breakage during bag making when forming bundles. Considering the above aspects, the lower limit of the elongation at break in the direction orthogonal to the main orientation axis is preferably 27%, more preferably 35%. When the elongation at break is 300% or less, it is effective in suppressing the deformation of the polyolefin film during vapor deposition and conveying, and it is also effective in suppressing deformation during bag making when forming packaging. On the other hand, the upper limit of the elongation at break in the direction orthogonal to the main orientation axis is preferably 250%, more preferably 200%, further preferably 120%, and particularly preferably 60%. It should be noted that, here, tensile elongation refers to the tensile elongation measured at 23°C with a tensile speed set to 300 mm / min. Tensile elongation can be measured using a well-known tensile testing apparatus, the detailed procedures of which are described below.

[0042] There are no particular limitations on the method for achieving a tensile elongation of 20% or more and 300% or less in the direction orthogonal to the main orientation axis; for example, a biaxially oriented film can be made from a polyolefin film. Furthermore, as the raw material for the A layer, it is preferable to prepare a composite resin raw material premixed from cyclic olefin resin and polypropylene resin, and then melt-extrude it into a sheet while controlling the content of the cyclic olefin resin.

[0043] From the perspective of improving thermal stability, it is important that the first and second polyolefin films of the present invention have at least one layer (layer A) comprising a cyclic olefin resin and a polypropylene resin. By configuring it in this way, the polyolefin film obtained has excellent thermal stability by utilizing the high thermal stability of the cyclic olefin resin and the excellent tensile properties of the polypropylene resin, for example, the barrier properties of the laminate with the vapor-deposited layer D described later are excellent.

[0044] It should be noted that the polyolefin membrane of the present invention can be any one of the following: a single membrane structure consisting of only one A layer; a laminated structure formed by laminating multiple A layers in the thickness direction to a total of two or more layers; or a laminated structure formed by laminating the A layer and layers other than the A layer in the thickness direction to a total of two or more layers. However, considering the membrane's tensile strength, excellent voltage resistance and reliability under high temperature conditions, and processability, it is preferable to have a B layer, which is mainly composed of polypropylene resin, contains more polypropylene resin than the A layer, and has a low content of cyclic olefin resin.

[0045] As specific embodiments of the laminated structure of the polyolefin film of the present invention, examples include, for instance, a two-layer structure of A layer / B layer, two three-layer structures of B layer / A layer / B layer, and A layer / B layer / A layer; three three-layer structures described later, including B layer / A layer / C layer and A layer / B layer / C layer, which have a layer (C layer) with a melting point lower than that of A layer and B layer and a melting point of 100°C or higher and 150°C or lower; and structures with four or more layers in which A layer is the inner layer of the film or the outermost layer of the two surfaces of the film. From the perspective of stretching film stability, the B layer / A layer / B layer or B layer / A layer / C layer structure is preferred. Here, when the overall film thickness is considered as 100%, the lower limit of the thickness of A layer is preferably 10%, more preferably 35%, further preferably 60%, and particularly preferably 80%. The upper limit is set to 100%, including a single layer. By making the thickness of layer A within the above range, the polyolefin film becomes a structure that is very thermally stable during vapor deposition. Therefore, when the vapor-deposited layer and layer D (described later) are laminated to form a laminate, it can have good water vapor barrier and oxygen barrier properties.

[0046] Furthermore, when the polyolefin film of the present invention has multiple A layers, their compositions can be the same or different. As lamination methods, examples include feed block method based on co-extrusion, multi-manifold method, coating method, etc. From the perspective of production efficiency and cost, lamination method based on co-extrusion (e.g., melt co-extrusion) is preferred.

[0047] In the polyolefin membrane of the present invention, the lower limit of the content of cyclic olefin resin in the whole membrane is preferably 1% by mass, more preferably 2% by mass, and even more preferably 3% by mass. On the other hand, the upper limit is preferably 39% by mass, more preferably 25% by mass, more preferably 19% by mass, even more preferably 14% by mass, particularly preferably 9% by mass, and most preferably 7.5% by mass. In addition, the lower limit of the content of cyclic olefin resin in the A layer of the membrane is preferably 1% by mass, more preferably 2% by mass. On the other hand, the upper limit is preferably 39% by mass, more preferably 25% by mass, more preferably 19% by mass, even more preferably 14% by mass, particularly preferably 10% by mass, and most preferably 9% by mass. By making the content of cyclic olefin resin in the whole membrane and in the A layer of the membrane within the preferred range, the area ratio is increased during biaxial stretching, and the water vapor barrier and oxygen barrier properties of the laminate with the D layer deposited on the membrane are good.

[0048] In the second polyolefin film of the present invention, when the cross section of layer A is cut using a surface parallel to both the main orientation axis and the thickness direction is defined as section X, it is important that within a 1μm × 2μm rectangle defined in section X with a pair of short sides parallel to the thickness direction, there are at least two regions of the cyclic olefin resin passing through the pair of short sides. In the polyolefin film of the present invention, it is preferable that there are at least four regions of cyclic olefin resin passing through the pair of sides parallel to the thickness direction, more preferably at least six regions. There is no particular upper limit, and it is set to 100 regions. It should be noted that the first polyolefin film of the present invention also preferably satisfies this condition, and the preferred numerical range is also the same.

[0049] It is believed that by creating two or more regions of cyclic olefin resin along a pair of sides parallel to the thickness direction, the cyclic olefin resin is dispersed in a more flattened, micro-dispersed state within the plane. The synergistic effect of the high thermal stability of the cyclic olefin resin and the excellent tensile strength of the polypropylene resin can suppress the movement of amorphous chains in the film. Therefore, for example, when laminating the D layer (described later) by vapor deposition, defects such as pinholes and cracks in the D layer caused by film shrinkage due to heat during vapor deposition can be suppressed, resulting in good water vapor barrier and oxygen barrier properties in the laminate with the D layer. Furthermore, during high-temperature treatments such as heat sterilization after bag manufacturing, film shrinkage can also be suppressed, preventing damage to water vapor barrier and oxygen barrier properties.

[0050] Within section X, as a method to ensure that the number of regions of cyclic olefin resin passing through a pair of sides parallel to the thickness direction is two or more, a method of controlling the regional structure (island structure) of layer A can be used. For example, as a raw material for layer A, it is effective to prepare a composite resin raw material by premixing cyclic olefin resin and polypropylene resin, melt extrude it into sheets while controlling the content of cyclic olefin resin, perform biaxial stretching at an area stretching ratio of 36.0 times or more (preferably 40.0 times or more), and perform heat treatment after biaxial stretching.

[0051] Hereinafter, in the polyolefin film of the present invention, the method for determining a rectangle with dimensions of 1 μm × 2 μm in cross section X with a pair of sides parallel to the thickness direction, and the method for determining the number of regions of cyclic olefin resin with a pair of sides parallel to the thickness direction will be described with reference to the accompanying drawings. Figure 1 This is a schematic diagram showing a 1μm × 2μm rectangle within a cross section X of a polyolefin film according to an embodiment of the present invention, defined with a pair of sides parallel to the thickness direction, and a region of cyclic olefin resin passing through the rectangle with a pair of sides parallel to the thickness direction. Figure 1The symbols 1 to 5 in the figure represent, respectively, a part of section X, the sea part, the island part (region), a rectangle with a size of 1μm × 2μm defined in section X with a pair of sides parallel to the thickness direction, and a pair of sides parallel to the thickness direction. Figure 1 The left image is a portion of section X, and the right image is an enlarged view of a rectangle (denoted by dashed lines) within section X, defined by a pair of sides parallel to the thickness direction, measuring 1 μm × 2 μm. It should be noted that in the polyolefin film of this invention, the sea portion is made of polypropylene resin, and the island portion is made of cyclic olefin resin.

[0052] When a 1μm × 2μm rectangle is defined within section X with a pair of sides parallel to the thickness direction, the base of this rectangle is designated as the sea area. Regions located on the side opposite the base are considered non-existent and not counted. Figure 1 In the example, such a region does not exist.

[0053] Here, "the region passing through a pair of cyclic olefin resins parallel to the thickness direction" refers to the region passing through a pair of cyclic olefin resins parallel to the thickness direction simultaneously. That is, in Figure 1 In the example (right figure), regions 4 to 7 from the top are equivalent to it, while regions 1 to 3 from the top are not equivalent to it. Therefore, in this example, there are 4 "regions of cyclic olefin resin passing through a pair of sides parallel to the thickness direction".

[0054] In the polyolefin film of the present invention, when layer C is defined as having a melting point lower than that of layers A and B, and a melting point of 100°C or higher but lower than 150°C, layer B is preferably located on one outermost surface, and layer C is located on the other outermost surface. Here, layer C melts at a temperature lower than that of layers A and B. Therefore, by melting only layer C at a temperature lower than that of layers A and B, layer C can function as a heat-sealing layer. Heat sealing refers to the state (or process) in which the films are melted and pressed together by heating when filling and packaging contents to obtain a bag. Heat-sealing property refers to the property of the film sides that are melted and pressed together by heating.

[0055] From the perspective of enabling the C layer to function as a heat-sealing layer at lower temperatures and higher speeds, the C layer preferably contains a polypropylene resin with low crystallinity and a low melting point. Specifically, ethylene-propylene random copolymers, ethylene-propylene-butene random copolymers, and propylene-butene random copolymers are preferred. Considering the above, the melting point of the C layer is preferably 110°C or higher and 148°C or lower, more preferably 120°C or higher and 145°C or lower. The melting point of the C layer can be read as the peak temperature of the endothermic peak generated by melting when analyzing the C layer of the film using differential scanning calorimetry (DSC).

[0056] In the polyolefin film of the present invention, when the tanδ of the main orientation axis direction at 50°C and 121°C, obtained by dynamic viscoelasticity measurement at a frequency of 10Hz, is set to tanδ50 and tanδ121, respectively, the ratio of tanδ50 / tanδ121 is preferably greater than 0.25 and less than 0.99. A tanδ50 / tanδ121 ratio greater than 0.25 means that the temperature dependence of the loss tangent (tanδ) is small. That is, the amorphous molecular chains within the film are less prone to movement under high-temperature conditions. For example, during the deposition of the D layer described above, defects such as pinholes and cracks in the D layer caused by film deformation due to heat during deposition can be suppressed, resulting in good water vapor barrier and oxygen barrier properties of the laminate with the D layer. Furthermore, film deformation caused by high-temperature treatments such as heat sterilization after bag making can also be suppressed, thus mitigating the reduction in water vapor barrier and oxygen barrier properties associated with such treatments. On the other hand, considering feasibility, the upper limit of tanδ50 / tanδ121 is set below 0.99. It should be noted that tanδ at each temperature can be obtained from the storage modulus and loss modulus read from the viscoelastic-temperature curve using the dynamic viscoelastic method. The determination methods for these moduli are described later along with those for the determination of each elastic modulus.

[0057] Considering the above aspects, the lower limit of the tanδ50 / tanδ121 ratio of the membrane is 0.28, preferably 0.31, more preferably 0.33, and even more preferably 0.35. On the other hand, the upper limit of the tanδ50 / tanδ121 ratio is preferably 0.89, more preferably 0.69.

[0058] To control tanδ50 / tanδ121 to be greater than 0.25 and less than 0.99, for example, it is effective to prepare a composite resin raw material made by premixing cyclic olefin resin and polypropylene resin as the raw material for layer A, melt extrude and sheet it based on controlling the content of cyclic olefin resin, make the area stretch ratio of 36.0 times or more (preferably 40.0 times or more), and make the preheating temperature before stretching in the width direction of biaxial stretching 5°C or more and 15°C or less higher than the stretching temperature in the width direction.

[0059] In view of imparting high barrier properties, the polyolefin film of the present invention preferably has a ten-point region height (S10z) of at least one surface of the aforementioned B layer, measured using a three-dimensional non-contact surface shape measuring instrument, that is 150 nm or more and 900 nm or less. Here, the ten-point region height (S10z) of the surface is a parameter obtained by summing the height of the five-point peak region (S5p: the average height of the peaks from the highest to the fifth highest peaks in the reference region) and the depth of the five-point valley region (S5v: the average height of the valleys from the deepest to the fifth deepest valleys (positive value) in the reference region) in the evaluation field of view image, by S5p + S5v. That is, the smaller (S10z) is, the smaller the surface unevenness, and conversely, the larger (S10z) is, the larger the surface unevenness.

[0060] For example, the surface area (S10z) of a film without particles tends to decrease, while the surface area (S10z) of a film containing coarse particles tends to increase. Considering the above, the lower limit of the ten-point region height (S10z) of the surface is preferably 180 nm, more preferably 200 nm. On the other hand, the upper limit is preferably 700 nm, more preferably 400 nm. In order to control the surface ten-point region height (S10z) to be 150 nm or more and 900 nm or less, for example, the following configuration is effective, even if the B layer described later contains a polypropylene resin and 1% by mass or more and 10% by mass or less of a thermoplastic resin incompatible with the polypropylene resin.

[0061] The polyolefin membrane of the present invention preferably comprises at least one of metal particles and inorganic compound particles. From the viewpoint of imparting high barrier properties and smooth membrane surface, the inorganic compound particles are, for example, any one of aluminum, alumina (sometimes called alumina), silicon oxide, cerium oxide, calcium oxide, diamond-like carbon film, or mixtures thereof, and particularly preferably comprise at least one of alumina, silicon dioxide, and oxides of aluminum and silicon.

[0062] The type of particle can be determined, for example, by energy dispersive X-ray analysis (EDS) and, if necessary, by EELS analysis using the GATAN GIF "Tridiem". In EELS analysis, the particle composition can be identified by comparing the obtained EELS spectrum with the EELS spectrum of a commercially available metal compound or commonly published EELS spectral data. As measuring instruments, EDS can use instruments such as the JED-2300F (manufactured by Nippon Electronics Corporation, semiconductor detector, Dry SD Extra), and EELS analysis can use instruments such as the JEM-2100F field emission transmission electron microscope (manufactured by Nippon Electronics Corporation, accelerating voltage 200 kV).

[0063] Furthermore, the aspect ratio of the metal particles and inorganic compound particles observed in the cross-section of the polyolefin film of the present invention when cut with a plane parallel to the main orientation axis and perpendicular to the thickness direction is preferably 2 or more. The more layered the particles are, the higher the barrier properties they exhibit; therefore, an aspect ratio of 10 or more is more preferred, 30 or more is even more preferred, and 50 or more is particularly preferred. There is no particular upper limit to the aspect ratio, which is set to 500.

[0064] There are no particular limitations on the method for achieving an aspect ratio of 2 or higher for the particles in the membrane. For example, a method using a laminate having a polyolefin membrane layer (described later) and a layer (D layer) containing a total of more than 50% by mass and less than 100% by mass of metals and inorganic compounds can be used as raw material. In this case, during the melting process of melting the laminate, it is preferable to perform melting with high shear and to melt the thin laminate of the D layer. It should be noted that the aspect ratio of the particles can be calculated as follows: the cross-sectional image of the particles obtained by observation using a SEM (scanning electron microscope) is enclosed by a rectangle with the smallest area, and the ratio of the length of its long side to the length of its short side is calculated.

[0065] The polyolefin membrane of the present invention preferably has at least one surface gloss level exceeding 130% and below 160%. A surface gloss level exceeding 130% means a low light scattering density on the membrane surface, resulting in a smooth surface. Therefore, by making the surface gloss level greater than 130%, defects such as pinholes and cracks generated in the D layer can be suppressed when forming a laminate with a D layer, resulting in good water vapor barrier and oxygen barrier properties of the laminate. On the other hand, when the surface gloss level exceeds 160%, it means that the surface is excessively smoothed, and sometimes the membrane's slippage can be drastically reduced. Therefore, by making the surface gloss level below 160%, the deterioration of operability during D layer deposition and the associated wrinkling can be suppressed, resulting in good water vapor barrier and oxygen barrier properties of the laminate. Considering the above aspects, a surface gloss level of 135% or more and 149% or less is more preferred, and 140% or more and 148% or less is even more preferred. It should be noted that gloss can be measured according to JISK-7105 (1981), the details of which are described below.

[0066] In order to control the surface gloss of the film to be greater than 130% and less than 160% or the preferred range mentioned above, it is effective to prepare a composite resin raw material made by premixing cyclic olefin resin and polypropylene resin as the raw material for layer A, melt extruding and sheeting it on the basis of controlling the content of cyclic olefin resin, forming a laminated structure having at least layer A and layer B, controlling the temperature of the molten sheet during cooling and solidification to be less than 30°C, and making the area stretch ratio more than 36.0 times (preferably more than 40.0 times).

[0067] The polyolefin film of the present invention is preferably a biaxially oriented film. By fabricating a biaxially oriented film, it is easy to control the storage modulus in the main orientation axis direction at 50°C and 121°C, as well as the tensile elongation in the direction orthogonal to the main orientation axis, obtained by dynamic viscoelasticity measurements at a frequency of 10 Hz, within the preferred range of the present invention. Here, a biaxially oriented film refers to a film in which the molecular chains are oriented in two orthogonal directions, which is usually obtained by stretching in two orthogonal directions.

[0068] The polyolefin film of the present invention can be widely used in industrial applications such as packaging, mold release, tape, and film capacitors. For suitability for film capacitor and packaging applications, the thickness is preferably greater than 0.5 μm and less than 60 μm. By making the thickness greater than 0.5 μm, relaxation during vapor deposition and transportation can be suppressed, thereby reducing film rupture caused by tension. From the above considerations, the lower limit of the thickness is more preferably 0.8 μm for capacitor applications, further preferably 1.2 μm, and more preferably 10 μm for packaging applications, further preferably 11 μm. On the other hand, setting the thickness to less than 60 μm not only improves operability but also reduces manufacturing costs. From the above considerations, the upper limit of the thickness is more preferably 5.5 μm for film capacitor applications, further preferably 4.0 μm, particularly preferably 3.2 μm, and more preferably 50 μm for packaging applications, further preferably 40 μm, particularly preferably 19 μm. It should be noted that the thickness of the membrane can be determined as follows: the thickness of the membrane is measured at any 10 points using a contact micrometer in an atmosphere of 23°C and 65% RH, and the arithmetic mean of all the measured values ​​is calculated.

[0069] There are no particular limitations on the methods used to achieve a polyolefin film thickness greater than 0.5 μm and less than 60 μm, or within the aforementioned preferred range. For example, methods such as adjusting the discharge rate during melt extrusion of the polyolefin resin composition, adjusting the rotation speed of the casting drum during the cooling and solidification of the molten sheet, adjusting the die lip gap of the die discharging the molten sheet, adjusting the stretch ratio in the length direction, and adjusting the stretch ratio in the width direction can be used. More specifically, the thickness of the polyolefin film can be reduced by decreasing the discharge rate, increasing the rotation speed of the casting drum, decreasing the die lip gap, and increasing the stretch ratio in the length and width directions.

[0070] Next, the resin preferably used in the polyolefin film of the present invention will be described. The A layer of the polyolefin film of the present invention, considering that the storage modulus in the main orientation axis direction at 50°C and 121°C, as measured by dynamic viscoelasticity at a frequency of 10 Hz, the thermal shrinkage rate in the main orientation axis direction at 150°C, and the tensile elongation in the direction orthogonal to the main orientation axis are within the ranges described above, is preferably composed mainly of a polypropylene resin, and the melting point of the A layer is 135°C or higher and 175°C or lower. Considering the above, the lower limit of the melting point of the A layer is preferably 140°C, more preferably 145°C, further preferably 150°C, particularly preferably 157°C, and most preferably 163°C. On the other hand, the upper limit of the melting point of the A layer is preferably 173°C, more preferably 171°C, and particularly preferably 169°C. By setting the melting point of the A layer within such a range, it is easy to control the E'121 / E'50 and the thermal shrinkage rate in the main orientation axis direction at 150°C of the film within the aforementioned preferred ranges. It should be noted that the melting point of layer A can be read as the peak temperature of the endothermic peak with the largest peak area among the endothermic peaks generated by the second round of melting when analyzing layer A of polyolefin films using differential scanning calorimetry (DSC). The detailed method for determining the melting point is described below.

[0071] In the polyolefin film of the present invention, the mesopentylene component ratio of the polypropylene resin used as the main component in layer B is preferably 0.900 or higher. The lower limit of the mesopentylene component ratio is preferably 0.930, more preferably 0.960, and even more preferably 0.970. The mesopentylene component ratio is an indicator of the stereoregularity of the crystalline phase of the polypropylene resin and is determined by nuclear magnetic resonance (NMR). In the polyolefin film of the present invention, by using a polypropylene resin with a mesopentylene component ratio of 0.90 or higher as the main component of layer B, the crystallinity of layer B is increased, which has the effect of improving the orientation of the polypropylene film (especially layer B). Therefore, when the polypropylene film is used for packaging purposes, deformation caused by heat during vapor deposition can be suppressed, and the D layer (described later), represented by the vapor-deposited film, can be easily and uniformly laminated. Furthermore, defects such as pinholes and cracks in layer D can also be suppressed. Therefore, the water vapor barrier and oxygen barrier properties of the laminated body containing layer D can be improved. It should be noted that, considering the feasibility and the need to improve the tightness between the B and D layers, the upper limit of the meso-five-unit component ratio is preferably 0.99, and more preferably 0.98.

[0072] The polypropylene resin used in the B layer of the polyolefin film of the present invention can be one type or a mixture of two or more types. However, from the viewpoint of reducing deformation caused by heat during vapor deposition when forming the film, the melting point of the polypropylene resin as the main component is preferably 151°C or higher, more preferably 153°C or higher, further preferably 155°C or higher, particularly preferably 158°C or higher, and most preferably 160°C or higher. By making the melting point of the polypropylene resin as the main component of the B layer 151°C or higher, the B layer can maintain high crystallinity, thus reducing the deformation of the polypropylene film caused by heat during vapor deposition. That is, when the D layer described later is vapor deposited, defects such as pinholes and cracks in the D layer are reduced, and the water vapor barrier and oxygen barrier properties of the laminate with the D layer are increased.

[0073] When two or more types of polypropylene resins are used in the B layer of the polyolefin film of the present invention, a modified polypropylene resin is suitable as the polypropylene resin other than the main component. By using the above-mentioned resin, the content of nitrogen and oxygen elements on the surface of the B layer increases, and the adhesion between the B layer and the D layer described later can be improved when laminating them. Examples of modified polypropylene resins include Mitsui Chemicals Co., Ltd.'s "Admer" series (unsaturated carboxylic acid modified polypropylene) and Sanyo Chemical Industry Co., Ltd.'s "Yumex" series (acid-modified low molecular weight polypropylene resin). From the viewpoint of maintaining the crystallinity of the B layer to a higher extent, when the total resin of the B layer is considered as 100% by mass, the content of modified polypropylene resin in the B layer is preferably 40% by mass or less, more preferably 30% by mass or less, and even more preferably 20% by mass or less.

[0074] Furthermore, in the B layer of the polyolefin film of the present invention, from the perspective of imparting surface smoothness, an incompatible resin that is incompatible with polypropylene resin can be added within a range that does not impair the effects of the present invention. When the total amount of resin constituting the B layer is considered to be 100% by mass, the amount of incompatible resin that is incompatible with polypropylene resin added is preferably 1% by mass or more and 10% by mass or less. From the perspective of imparting surface smoothness to the polyolefin film, the incompatible resin that is incompatible with polypropylene resin is preferably 2% by mass or more, more preferably 3% by mass or more, and the upper limit is preferably 9% by mass, more preferably 8% by mass.

[0075] Here, as an incompatible resin, polymethylpentene resins are particularly preferred from the perspective of high affinity with polypropylene resins and the ability to reduce the size of the regions. Furthermore, regarding the melting point of polymethylpentene resins, considering extrusion stability when blended with polypropylene and the ability to impart surface roughness using the regional island structure, 185°C to 240°C is preferred, and more preferably 220°C to 240°C. Based on these characteristics, in the polypropylene film of the present invention, polymers from which 80 mol% and 100 mol% of the structural units are derived from 4-methylpentene-1 are preferred, for example, the "TPX" (registered trademark) MX series, "TPX" (registered trademark) DX series, and "TPX" (registered trademark) RT series sold by Mitsui Chemicals Co., Ltd. as part of the "TPX" (registered trademark) series are preferred. Specifically, considering the high affinity with polypropylene resins and the ability to reduce the area size, "TPX" (registered trademark) MX002, MX004, DX310, DX845, and RT31 are preferred.

[0076] The cyclic olefin resin used in the polyolefin film of the present invention will now be described. The cyclic olefin resin is obtained, for example, primarily by polymerizing cyclic olefin monomers.

[0077] Examples of cyclic olefin monomers include monocyclic olefins such as cyclobutene, cyclopentene, cycloheptene, cyclooctene, cyclopentadiene, and 1,3-cyclohexadiene; bicyclic [2,2,1]hept-2-ene; 5-methyl-bicyclic [2,2,1]hept-2-ene; 5,5-dimethyl-bicyclic [2,2,1]hept-2-ene; 5-ethyl-bicyclic [2,2,1]hept-2-ene; 5-butyl-bicyclic [2,2,1]hept-2-ene; 5-ethylidene-bicyclic [2,2,1]hept-2-ene; 5-hexyl-bicyclic [2,2,1]hept-2-ene; 5-octyl-bicyclic [2,2,1]hept-2-ene; 5-octadecyl-bicyclic [2,2,1]hept-2-ene; and 5-methylene-bicyclic [2,2,1]hept-2-ene. Bicyclic olefins such as [1]hep-2-ene, 5-vinyl-bicyclo[2,2,1]hep-2-ene, and 5-propenyl-bicyclo[2,2,1]hep-2-ene; tricyclic[4,3,0,12.5]dec-3,7-diene, tricyclic[4,3,0,12.5]dec-3-ene, tricyclic[4,3,0,12.5]undec-3,7-diene, tricyclic[4,3,0,12.5]undec-3,8-diene, tricyclic[4,3,0,12.5]undec-3-ene, 5-cyclopentyl-bicyclo[2,2,1]hep-2-ene, 5-cyclohexyl-bicyclo[2,2,1]hep-2-ene, 5-cyclohexenylbicyclo[2,2,1]hep-2-ene, and 5-phenyl-bicyclo[2 Tricyclic alkenes such as hept-2-ene, tetracyclic dodecane-3-ene, 8-methyltetracyclic dodecane-3-ene, 8-ethyltetracyclic dodecane-3-ene, 8-methylenetetracyclic dodecane-3-ene, 8-ethylenetetracyclic dodecane-3-ene, 8-vinyltetracyclic dodecane-3-ene, 8-propenyltetracyclic dodecane-3-ene, etc. Alkenes of this type, and 8-cyclopentyl-tetracyclo[4,4,0,12.5,17.10]dodec-3-ene, 8-cyclohexyl-tetracyclo[4,4,0,12.5,17.10]dodec-3-ene, 8-cyclohexenyl-tetracyclo[4,4,0,12.5,17.10]dodec-3-ene, 8-phenyl-cyclopentyl-tetracyclo[4,4,0,12.5,17.10]dodec-3-ene, tetracyclo[7,4,13.6,01.9,02.7]tetradec-4,9,11,13-tetraene, tetracyclo[8,4,14.7,01.10,03.8]pentadecadec-5,10,12,14-tetraene, pentadecane[6,6,13.6,02.7,09.Polycyclic olefins such as

[14] -4-hexadecene, pentacyclic [6,5,1,13.6,02.7,09.13]-4-pentadecanene, pentacyclic [7,4,0,02.7,13.6,110.13]-4-pentadecanene, heptacyclic [8,7,0,12.9,14.7,111.17,03.8,012.16]-5-eicosene, heptacyclic [8,7,0,12.9,03.8,14.7,012.17,113.16]-14-eicosene, and cyclopentadiene tetramers are examples of cyclic olefins. These cyclic olefin monomers can be used alone or in combination of two or more.

[0078] As cyclic olefin monomers, from the perspectives of productivity and surface properties, the following are preferred: bicyclic [2,2,1]hept-2-ene (hereinafter referred to as norbornene), tricyclic [4,3,0,12.5]dec-3-ene (hereinafter referred to as tricyclic decene), tetracyclic [4,4,0,12.5,17.10]dodec-3-ene (hereinafter referred to as tetracyclic dodecene), cyclopentadiene, or 1,3-cyclohexadiene.

[0079] If the total number of structural units from cyclic olefin monomers in 100 mol% of the polymer exceeds 20 mol% but is less than 100 mol%, it is preferable to use either a resin formed by polymerizing only the cyclic olefin monomers (hereinafter, sometimes referred to as COP) or a resin formed by copolymerizing the cyclic olefin monomers with chain olefin monomers (hereinafter, sometimes referred to as COC), or a mixture of both.

[0080] Methods for manufacturing COPs include known methods such as addition polymerization or ring-opening polymerization of cyclic olefin monomers. Examples include methods such as hydrogenation of norbornene, tricyclodecene, tetracyclodecene, and their derivatives after ring-opening metathesis polymerization; addition polymerization of norbornene and its derivatives; and hydrogenation of cyclopentadiene and cyclohexadiene after 1,2- and 1,4-addition polymerization. Among these methods, the method of hydrogenation of norbornene, tricyclodecene, tetracyclodecene, and their derivatives after ring-opening metathesis polymerization is more preferred in terms of productivity and moldability.

[0081] In the case of COC (Copolymerization of Cyclic Olefins), preferred linear olefin monomers for copolymerization include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 3-methyl-1-butene, 3-methyl-1-pentene, 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, and 1-eicosene. Among these, ethylene is particularly preferred from the perspectives of productivity and cost. Furthermore, known methods for manufacturing resins by copolymerizing cyclic olefin monomers with linear olefin monomers include addition polymerization of cyclic olefin monomers with linear olefin monomers, and methods such as addition polymerization of norbornene and its derivatives with ethylene are also available. From the perspective of productivity and formability, a binary or ternary copolymer containing norbornene or tricyclodecene as cyclic olefin monomers, ethylene and / or propylene as chain olefin monomers is preferred.

[0082] The cyclic olefin resin used in the polyolefin film of the present invention is preferably amorphous. Furthermore, regarding the glass transition temperature of the amorphous cyclic olefin resin, considering that the thermal shrinkage rate along the main orientation axis at E'121 / E'50, 150°C, of ​​the polyolefin film is controlled within the aforementioned preferred range, it is preferably 125°C or higher, more preferably 130°C or higher, and even more preferably 135°C or higher. By setting the glass transition temperature to 125°C or higher, the thermal stability during film formation is improved. While there is no particular upper limit, it is set to 200°C from the perspective of film-forming properties. It should be noted that the amorphous nature of the cyclic olefin resin in the polyolefin film of the present invention is defined as: the melting peak temperature (Tm) obtained when the cyclic olefin resin is heated from 30°C to 260°C at a rate of 20°C / min and cannot be observed using differential scanning calorimetry (DSC).

[0083] Even when the polyolefin membrane of the present invention is mainly composed of polypropylene resin, it may contain resins other than polypropylene resin and cyclic olefin resins within a range that does not impair the purpose of the present invention. Specific examples of resins include vinyl polymer resins, polyester resins, polyamide resins, polyphenylene sulfide resins, polyimide resins, polycarbonate resins, etc., which contain various polyolefin resins; polymethylpentene and syndiotactic polystyrene are particularly preferred examples. When the total resin component constituting the polyolefin membrane is considered as 100% by mass, the content of resins other than polypropylene resin and cyclic olefin resins is preferably less than 3% by mass, more preferably less than 2% by mass, and even more preferably less than 1% by mass. When the content of resins other than polypropylene resin and cyclic olefin resins is 3% by mass or more, the influence of the regional interface becomes greater, and therefore, sometimes the tensile strength decreases, or the water vapor barrier and oxygen barrier properties of the laminate with the D layer decrease. It should be noted that there are no particular limitations on the layers containing these components.

[0084] The polyolefin film of the present invention can be widely used in industrial applications such as packaging, demolding, tape, and film capacitors. For example, especially when used in packaging, it is suitable as a polyolefin film with excellent thermal structural stability during vapor deposition and good thermal water vapor and oxygen barrier properties during heat sterilization treatment.

[0085] <Laminated Body>

[0086] Next, the laminate of the present invention will be described. As the laminate of the present invention, at least one surface of the polyolefin membrane of the present invention has a layer (D layer) comprising a total of more than 50% by mass and less than 100% by mass of metals and inorganic compounds. Here, "a layer comprising a total of more than 50% by mass and less than 100% by mass of metals and inorganic compounds" means, when all components constituting the layer are considered as 100% by mass, a layer comprising only more than 50% by mass of metals, a layer comprising only more than 50% by mass of inorganic compounds, or a layer comprising both metals and inorganic compounds, and whose total exceeds 50% by mass. The metals and / or inorganic compounds used as the D layer are preferably, for example, aluminum, alumina, silicon oxide, cerium oxide, calcium oxide, diamond-like carbon film, or mixtures thereof, from the perspective of improving adhesion to the membrane, improving gas barrier properties when laminated to the membrane, and reducing environmental impact.

[0087] Here, when the polyolefin film has a laminated structure, the average height (Spk) of the protruding peaks on the surface of the D layer, measured by a three-dimensional non-contact surface roughness meter, is preferably 10 nm or more and 400 nm or less. By setting Spk to 10 nm or more, moderate smoothness can be imparted, enabling film transport in the vapor deposition process and achieving high water vapor barrier and oxygen barrier properties. On the other hand, by setting Spk to 400 nm or less, the formation of steep protrusions can be suppressed, thus mitigating the reduction in water vapor barrier and oxygen barrier properties caused by defects such as pinholes and cracks in the D layer resulting from these protrusions. Considering the above aspects, the lower limit of Spk is preferably 20 nm, more preferably 30 nm, and even more preferably 40 nm. On the other hand, the upper limit of Spk is preferably 350 nm, more preferably 250 nm, even more preferably 150 nm, and particularly preferably 130 nm.

[0088] In order to control the Spk of the laminate to the above-mentioned preferred range, it is effective to prepare a composite resin raw material made by premixing cyclic olefin resin and polypropylene resin as the raw material for layer A, melt extrude it into a sheet while controlling the content of cyclic olefin resin, form a laminate structure, control the cooling temperature when the molten sheet is cooled and solidified to a low level (preferably below 30°C), and perform biaxial stretching with an area stretching ratio of 36.0 times or more (preferably 40.0 times or more).

[0089] From the perspectives of recyclability (allowing the laminate to be recycled as a resin or film), improved barrier properties (resistance to breakage), and visibility of the contents when made into packaging materials, the thickness of layer D in the laminate of the present invention is preferably 200 nm or less. From the above considerations, it is more preferably 110 nm or less, further preferably 50 nm or less, and even more preferably 30 nm or less. There is no particular limitation on the lower limit; from the perspective of barrier properties, it is set to 1 nm.

[0090] Furthermore, in the laminate of the present invention, a resin layer with a thickness of 1 μm or less may be formed between the D layer and the surface of the polyolefin film by coating or the like. By forming this resin layer, effects such as improved adhesion between the D layer and the polyolefin film can sometimes be obtained. However, considering manufacturing costs and recyclability, it is preferable to have a method without this resin layer (i.e., the D layer is directly laminated to the outermost surface of the polyolefin film), and even more preferable to have the D layer on the surface of the B layer of the polyolefin film.

[0091] As a method for forming a laminate by forming a D layer on the polyolefin film of the present invention, methods such as coating, vapor deposition, and lamination can be included. From the perspective of being independent of humidity and being able to exhibit excellent gas barrier properties in the thin film, vapor deposition is particularly preferred. As a vapor deposition method, physical vapor deposition methods such as vacuum vapor deposition, EB vapor deposition, sputtering, and ion plating, as well as various chemical vapor deposition methods such as plasma CVD, can be used. From the perspective of productivity, vacuum vapor deposition is particularly preferred.

[0092] Furthermore, from the perspective of improving the oxygen permeability of the laminate of the present invention, for example, a top coating comprising an organic-inorganic mixture can be laminated onto the surface of layer D. A preferred example of the top coating is a mixture of alkoxides and / or condensates of metal or silicon atoms with a water-soluble polymer.

[0093] <Packaging materials, bundles>

[0094] The packaging material and bundle of the present invention will be described below. The packaging material of the present invention is characterized by having at least one of the polyolefin film of the present invention and the laminate of the present invention. The packaging material of the present invention exhibits excellent thermal structural stability during vapor deposition, particularly good water vapor barrier and oxygen barrier properties when laminating transparent vapor-deposited layers. Therefore, although it is easily degraded by water vapor and oxygen, it is suitable for packaging.

[0095] The bundling body of the present invention is characterized by using the packaging material of the present invention to bundle the contents. The contents are not particularly limited, but considering the excellent transparency, water vapor barrier, and oxygen barrier properties of the packaging material of the present invention, materials that are easily degraded by water vapor and oxygen are preferred to ensure external visibility. It should be noted that the bundling body of the present invention is obtained by covering the contents with the packaging material of the present invention, and its shape is not particularly limited. For example, a bundling body obtained by heat-sealing the packaging material of the present invention into a bag shape and placing the contents therein can be cited. Specific examples of such packaging bodies include retort pouches for food products.

[0096] <Manufacturing Method>

[0097] The polyolefin film of the present invention can be obtained by biaxial stretching, heat treatment, and relaxation treatment using raw materials capable of imparting the above-mentioned properties. As a method of biaxial stretching, it can be obtained by simultaneous biaxial stretching with inflation, simultaneous biaxial stretching with a tenter frame, or sequential biaxial stretching with a tenter frame. However, considering the improvement of film formation stability, crystalline / amorphous structure, surface properties, and especially the improvement of the stretching ratio of the present invention while controlling mechanical properties and thermal dimensional stability, sequential biaxial stretching with a tenter frame or simultaneous biaxial stretching with a tenter frame is preferred.

[0098] Next, an example of the method for manufacturing the polyolefin film of the present invention will be described. First, a composite resin raw material, pre-mixed with a cyclic olefin resin and a polypropylene resin, is diluted or directly melt-extruded onto a support to form an unstretched film. This unstretched film is then stretched along its length, followed by stretching along its width, and subjected to sequential biaxial stretching. Subsequently, heat treatment and relaxation treatment are performed to manufacture a biaxially oriented polyolefin film. A more detailed description will follow, but the present invention is not necessarily limited thereto.

[0099] First, for the polyolefin membrane of the present invention, to achieve a good dispersion of the cyclic olefin resin and the polypropylene resin (A), and to control the E'121 / E'50 to be greater than 0.25 and less than 0.99, a membrane with low temperature dependence of storage modulus is obtained. Therefore, particularly considering the suppression of membrane deformation caused by heat during the deposition of the D layer on the membrane, and the good water vapor barrier and oxygen barrier properties of the laminate with the D layer, it is preferable to pre-mix the cyclic olefin resin, the polypropylene resin, and the antioxidant to form a composite. The composite can be formed using a short-shaft extruder, a bi-shaft extruder, etc.; considering the good dispersion and high thermal stability, a bi-shaft extruder is particularly preferred.

[0100] The amount of antioxidant is preferably 0.2 parts by mass or more, more preferably 0.3 parts by mass or more, and even more preferably 0.4 parts by mass or more, relative to 100 parts by mass of the composite resin component. The upper limit is set to 1.0 parts by mass.

[0101] Next, a resin raw material formed by mixing a cyclic olefin resin and a polypropylene resin is fed to a single-screw extruder for layer A. Polypropylene resin or a polypropylene resin composition, serving as the raw material for layer B, and polypropylene resin or a polypropylene resin composition, serving as the raw material for layer C, are respectively fed to single-screw extruders for layers B and C. Melt extrusion is performed from the single-screw extruders for layers A, B, and C, with the extrusion temperature set to 220°C to 280°C, preferably 230°C to 270°C, to remove impurities by passing the resin through a filter. Then, the molten resin is combined in a laminating device such as a feed block in a manner that forms a desired layered structure (e.g., layer b / a / c when the unstretched layer A is designated as layer a, the unstretched layer B as layer b, and the unstretched layer C as layer c). Finally, it is extruded from a slit die at a temperature of 200°C to 260°C.

[0102] Here, considering the need to ensure sufficient resin melting during melt extrusion to prevent shearing caused by screw rotation from breaking molecular chains, thus maintaining film stability even at high temperatures without relaxation, it is preferable to set the temperature before the filter to high, the temperature after the filter to lower than the temperature before the filter, and the die temperature just before discharge to a multi-stage low-temperature setting that allows for further low-temperature reduction. Furthermore, the oxygen concentration in the raw material feed hopper is preferably 1% or less (volume basis, the same below), more preferably 0.1% or less, and even more preferably 0.05% or less. By maintaining the oxygen concentration in the raw material feed hopper at 1% or less, oxidative degradation of the polypropylene resin can be suppressed, easily controlling E'121 / E'50 within the preferred range of this invention.

[0103] Next, the molten resin sheet extruded from the slit die is cooled and solidified on a casting drum (cooling drum) with the surface temperature controlled at 10°C to 40°C to obtain an unstretched film. At this time, when co-extruding and laminating in such a way that the drum surface side initially in contact with the molten sheet extruded from the die becomes the B layer, it is easy to control the roughness parameter of the D layer formed on the surface of the B layer within the desired range, which is therefore preferred.

[0104] As a method for sealing the molten sheet and the casting drum, any one of the following can be used: electrostatic application, sealing using the surface tension of water, air knife method, pressure roller method, underwater casting method, air chamber method, etc. Furthermore, a combination of multiple methods can be used. The air knife method, which provides good film planarity and allows for control of surface roughness, is preferred. In addition, when using the air knife method, to prevent film vibration, it is preferable to appropriately adjust the position of the air knife by allowing air to flow downstream of the film forming process.

[0105] From the perspective of smoothing the surface of the obtained polypropylene film and improving the thickness uniformity and adhesion of the D layer formed by vapor deposition, the surface temperature of the casting drum is preferably 10°C to 35°C, more preferably 10°C to 30°C, and particularly preferably 10°C to 25°C. By setting such a temperature range, the mesophase fraction of the surface portion of the unstretched film, especially the roller side (the side that becomes the B layer after stretching), can be increased, so that the unstretched film has a mesophase structure.

[0106] The mesophase refers to a phase between crystalline and amorphous materials, specifically formed when solidifying from a molten state at a very rapid cooling rate. It is generally known that when polypropylene is cooled and solidified, crystallization occurs, resulting in spherulite growth. However, it is believed that stretching an unstretched film with such spherulites leads to differences in tensile stress within the spherulites, between the crystalline and amorphous parts of the spherulites, and other locations, resulting in localized stretching inhomogeneities and consequently, uneven thickness and structure. On the other hand, the mesophase does not take the spherulite form, thus avoiding stretching inhomogeneities and exhibiting higher stretching uniformity. Consequently, the resulting film exhibits high thickness uniformity, low surface roughness, and is easily made uniform.

[0107] Next, the unstretched film is biaxially stretched to achieve biaxial orientation. More specifically, the unstretched film is held at a temperature preferably 100–170°C, more preferably 120–165°C, and stretched along its length to a length preferably 2.0–12 times, more preferably 3.0–11 times, further preferably 4.0–10 times, particularly preferably 4.5–10 times, and most preferably 5.0–9.0 times, and then cooled to room temperature.

[0108] Next, the membrane, having been uniaxially stretched along its length, is fed into a tenter frame while its two ends in the width direction are held in a clamp. Here, in this invention, by setting the temperature of the preheating process before stretching in the width direction to the stretching temperature in the width direction +5 to +15°C, the highly oriented fibrillary structure in the length direction can be further strengthened through uniaxial stretching. Therefore, the temperature dependence of the membrane's storage modulus can be reduced, and E'121 / E'50 can be easily controlled within the aforementioned preferred range. Furthermore, from the perspective of improving thermal dimensional stability, it is preferable to stabilize the insufficiently oriented molecular chains by high-temperature preheating after uniaxial stretching. Considering the above, the upper limit of the temperature of the preheating process before stretching in the width direction is preferably the stretching temperature in the width direction +12°C, and more preferably the stretching temperature in the width direction +10°C.

[0109] Next, while holding the two ends of the film in the width direction with a clamp, the film is stretched in the width direction. From the viewpoint of controlling E'121 / E'50 to the above-mentioned preferred range, the stretching temperature in the width direction is preferably 150 to 175°C, more preferably 155 to 175°C.

[0110] Considering reducing the temperature dependence of the film's storage modulus and easily controlling E'121 / E'50 within the aforementioned preferred range, the stretching ratio in the width direction is preferably 6.0 to 20.0 times, more preferably 8.1 to 17.0 times, and even more preferably 9.1 to 15.0 times. By making the stretching ratio in the width direction 6.0 times or more, the orientation contribution of the highly oriented fibrillary structure in the length direction, achieved through uniaxial stretching, is mitigated. Therefore, film deformation caused by heat during the deposition of the D layer on the film is reduced, and the water vapor barrier and oxygen barrier properties of the laminate with the D layer are maintained. Furthermore, compared to the length direction, increasing the stretching ratio in the width direction can impart orientation in the width direction while maintaining the highly oriented state in the length direction. Therefore, the in-plane molecular chain tension is increased, thereby particularly improving the temperature dependence of the storage modulus.

[0111] Here, the area stretching ratio is preferably 36.0 times or more. By making the area stretching ratio 36.0 times or more, the molecular chain tension within the film surface is increased, and the regional structure becomes smaller or thinner. Therefore, the temperature dependence of the storage modulus during film fabrication can be reduced, thermal dimensional stability can be improved, and elongation at break can be increased. As a result, for the obtained film, deformation caused by heat during the deposition of the D layer on the film is suppressed, and the laminate with the D layer exhibits excellent water vapor barrier and oxygen barrier properties. In this invention, the area stretching ratio refers to the value obtained by multiplying the stretching ratio in the length direction by the stretching ratio in the width direction. Considering the above aspects, the area stretching ratio is more preferably 38.0 times or more, further preferably 40.0 times or more, and particularly preferably 44.0 times or more. There is no particular upper limit to the area stretching ratio; from the perspective of feasibility, it is 90.0 times in the case of sequential biaxial stretching and 150 times in the case of simultaneous biaxial stretching.

[0112] For the polyolefin films of the present invention, it is important to reduce the temperature dependence of the storage modulus and the thermal shrinkage rate in the main orientation axis direction at 150°C while setting a high area stretching ratio, and to increase the tensile elongation in the direction orthogonal to the main orientation axis. That is, in the present invention, it is preferable to improve the dispersibility of the cyclic olefin resin regions dispersed in the polypropylene resin, so that the preheating temperature during biaxial stretching and then stretching in the width direction is a higher temperature than the stretching temperature.

[0113] In the manufacture of the polypropylene film of the present invention, in the subsequent heat treatment and relaxation processes, while the two ends in the width direction are held taut with a clamp, a heat treatment at a temperature of 145°C or higher and 170°C is performed while relaxing the film by 2 to 20% in the width direction. This is preferred from the perspective of removing residual strain in the film and improving thermal dimensional stability. Such treatment, in particular, can suppress film deformation caused by heat during the deposition of the D layer on the film, resulting in good water vapor barrier and oxygen barrier properties in the laminate containing the D layer. Considering the above, the lower limit of the heat treatment temperature is preferably 150°C, more preferably 155°C, and even more preferably 160°C. In the relaxation process, from the perspective of improving the thermal structural stability of the film, the lower limit of the relaxation rate is preferably 5%, more preferably 8%, and even more preferably 11%, while the upper limit is preferably 18%, and even more preferably 17%.

[0114] After the above heat treatment and relaxation processes, the film is guided to the outside of the tenter frame, and the clamps at both ends of the film width direction are released in a room temperature atmosphere. In the winding process, the blank parts on both sides of the film width direction are cut open.

[0115] Next, in order to improve the peel strength of the D layer, it is preferable to perform an online surface modification treatment on the surface of the layer (D layer) containing a total of more than 50% by mass and less than 100% by mass of metals and inorganic compounds (typically the surface that contacts the casting drum). Examples of online surface modification treatments include, for example, corona discharge treatment in the atmosphere, or in an atmosphere of oxygen, nitrogen, hydrogen, argon, carbon dioxide, silane gas or mixtures thereof, or plasma treatment, ion beam treatment, etc.

[0116] In particular, corona discharge treatment is effective when carried out in an atmosphere with an oxygen concentration of 10% or less, preferably 5% or less, and more preferably 1% or less. Specifically, nitrogen, carbon dioxide, or mixtures thereof are preferred as an example of an atmosphere with an oxygen concentration of 1% or less; in particular, a mixture of nitrogen and carbon dioxide is effective. Furthermore, combining corona discharge treatment in the aforementioned atmosphere with plasma treatment or ion beam treatment is also effective. By treating in this atmosphere, the formation of low molecular weight substances associated with the cleavage of polypropylene molecular chains can be suppressed on the membrane surface, and hydrophilic functional groups can be effectively introduced, thus easily improving the peel strength of the D layer from the polyolefin membrane. The resulting membrane is then wound into a roll to obtain the polyolefin membrane of the present invention.

[0117] It should be noted that, in order to obtain the polyolefin film of the present invention, the manufacturing conditions of interest are specifically listed as examples below. It should be noted that it is preferable to satisfy all of these manufacturing conditions, but it is not necessarily required that all of them be present in the embodiment; appropriate combinations are also possible. For example, instead of "in sequential biaxial stretching, the preheating temperature before stretching in the width direction is the stretching temperature in the width direction + 5 to the stretching temperature in the width direction + 15°C", simultaneous biaxial stretching can be used.

[0118] • Premix cyclic olefin resins with polypropylene resins.

[0119] Regarding extrusion conditions, the system is set to a high temperature before the filter, a low temperature after passing through the filter compared to before the filter, and an even lower temperature at the die just before discharge (multi-stage low-temperature treatment).

[0120] • Ensure that the oxygen concentration in the raw material feeding hopper is below 1%.

[0121] • The above-mentioned premixed resin raw material is used in layer A, and a laminated structure with layer A as the inner layer is formed.

[0122] • The area stretching ratio of biaxial stretching is more than 36.0 times.

[0123] • In sequential biaxial stretching, the preheating temperature before stretching in the width direction is the stretching temperature in the width direction +5 to the stretching temperature in the width direction +15℃.

[0124] • After biaxial stretching, a relaxation of 2 to 20% is applied in the width direction, and then heat treatment is performed at a temperature of 145°C or higher and 170°C or lower.

[0125] <Metal-film laminates, thin-film capacitors formed using them, and their manufacturing methods>

[0126] The metal film laminate of the present invention has a metal film on at least one side of the polyolefin film of the present invention. This metal film laminate can be obtained by providing a metal film on at least one side of the polypropylene film of the present invention described above.

[0127] In this invention, the method of applying the metal film is not particularly limited. For example, a method of depositing a metal film, such as an aluminum or aluminum-zinc alloy vapor-deposited film on at least one side of a polyolefin film to serve as an internal electrode of a thin-film capacitor, is preferred. In this case, other metal components such as nickel, copper, gold, silver, and chromium may also be vapor-deposited simultaneously with or sequentially with aluminum. Alternatively, a protective layer may be applied to the vapor-deposited film using oil or the like. When the surface roughness of the polyolefin film differs between the front and back sides, from the perspective of improving voltage withstand capability, it is preferable to deposit the metal film on the side with the smoother surface roughness to form a metal film laminate.

[0128] In this invention, the metal film laminate can be annealed or heat-treated at a specific temperature after the metal film is formed, as needed. Additionally, for insulation or other purposes, a resin such as polyphenylene ether can be coated on at least one surface of the metal film laminate.

[0129] The thin-film capacitor of the present invention is formed using the metal film laminate of the present invention. That is, the thin-film capacitor of the present invention has the metal film laminate of the present invention.

[0130] For example, by laminating or winding the metal film laminate of the present invention using various methods, the thin-film capacitor of the present invention can be obtained. A preferred manufacturing method for a wound-type thin-film capacitor will be described below.

[0131] Aluminum is vapor-deposited onto one side of a polyolefin film under reduced pressure. The deposition forms stripes with blank areas extending along the length direction. Next, a cutting edge is inserted into the center of each vapor-deposited portion and the center of each blank portion on the surface to create a strip roll with blank areas on one side of the surface. For the strip roll with blank areas on the left or right, one roll each with blank areas on the left and right are stacked and wound together so that the vapor-deposited portion extends from the blank area in the width direction, resulting in a wound body.

[0132] When vapor deposition is performed on both sides, stripes with blank areas extending along the length of one side are vapor-deposited, and stripes are vapor-deposited on the other side with the blank areas along the length of the back side vapor-deposited area located in the center. Next, a blade is inserted into the center of the blank areas on both sides to cut open, creating a strip-shaped roll with blank areas on one side on each side (for example, if there is a blank area on the right side of the surface, there is a blank area on the left side of the back side). The resulting roll and one undeposited laminate film are stacked together with the metallized film protruding from the laminate film in the width direction and wound to obtain a wound body.

[0133] As a method for obtaining the thin-film capacitor of the present invention from the metal laminate film of the present invention, for example, a method can be described as follows: drawing out the core material from the winding body prepared as described above and pressing it, spraying metal film onto both end faces to form external electrodes, and welding leads onto the metal film to form a wound-type thin-film capacitor. The applications of thin-film capacitors are diverse, including power control units for electric vehicles such as electric cars, hybrid vehicles, and fuel cell vehicles, electric aircraft such as drones, railway vehicles, solar and wind power generation, and general household appliances. The thin-film capacitor of the present invention can also be applied to these applications.

[0134] The following describes the power control unit, electric vehicle, and electric aircraft of the present invention. The power control unit of the present invention includes the thin-film capacitor of the present invention. The power control unit is a system for managing power in electric vehicles, electric aircraft, and the like, which have a mechanism driven by electricity. By incorporating the thin-film capacitor of the present invention into the power control unit, miniaturization, improved heat resistance, and increased efficiency of the power control unit itself can be achieved, resulting in improved fuel efficiency.

[0135] The electric vehicle of the present invention includes the power control unit of the present invention. Here, electric bicycle refers to an electric vehicle, hybrid vehicle, fuel cell vehicle, or other vehicle that has a mechanism for being driven by electricity. As described above, the power control unit of the present invention is not only miniaturized but also has excellent heat resistance and efficiency. Therefore, by equipping an electric vehicle with the power control unit of the present invention, improvements in fuel efficiency can be achieved.

[0136] Example

[0137] The present invention will be described in more detail below with examples, but the present invention is not limited to the methods shown below. It should be noted that the evaluation of each item is carried out using the following methods.

[0138] <Methods for determining characteristic values ​​and methods for evaluating effects>

[0139] The method for measuring the characteristic values ​​and the method for evaluating the effects in this invention are described below.

[0140] (1) Determination of the direction of the principal orientation axis

[0141] Prepare a polyolefin membrane, with its length facing upwards, and cut it into rectangles 150 mm long and 10 mm wide, as sample <1>. Define the direction of the long side of sample <1> as 0°. Next, collect samples <2> of the same size with the long side oriented 15° to the right from the 0° direction. Repeat this process below, rotating the long side of each rectangular sample by 15° each time, and collecting samples in the same manner. <3> ~ <12> Next, for each rectangular sample, it was mounted on a tensile testing machine (Origintech "Tensilon" (registered trademark) UCT-100) with the long side direction as the tensile direction and the initial chuck distance 20 mm. Tensile tests were conducted at a tensile speed of 300 mm / min under an atmosphere of 23°C. The maximum load until the sample broke was recorded, and this value was divided by the cross-sectional area of ​​the sample before the test (film thickness × width) to calculate the stress at the maximum point strength. Five identical measurements were performed on each sample, and the average stress at the maximum point strength was calculated. The long side direction of the sample with the largest average value was taken as the main orientation axis direction of the polyolefin film, and the direction orthogonal to it within the film surface was taken as the direction orthogonal to the main orientation axis of the polyolefin film.

[0142] (2) Membrane thickness

[0143] The thickness of a polyolefin film was measured at 10 random locations using a contact electronic micrometer (Type K-312A) manufactured by Anritsu Co., Ltd., under an atmosphere of 23°C and 65% RH. The arithmetic mean of the thicknesses at these 10 locations was taken as the film thickness (unit: μm).

[0144] (3) The ratio of storage modulus along the main orientation axis: E'121 / E'50

[0145] Under the apparatus and conditions shown below, a rectangular polyolefin film (width (short side) 10 mm × length (long side) 20 mm), cut with the main orientation axis as the long side, is mounted in the chuck of the apparatus at 23°C and placed inside the furnace. The furnace atmosphere containing the film is cooled with liquid nitrogen, and the temperature is raised from -100°C to 180°C for measurement. A viscoelastic-temperature curve is plotted using dynamic viscoelasticity measurements, and the storage modulus (E'50) at 50°C is read. It should be noted that the number of tests is set to n=3, and the average value of the storage modulus (E'50) is calculated. Similarly, the number of tests is set to n=3, and the storage modulus (E'121) at 121°C is read from the viscoelastic-temperature curve, and its average value is obtained. The average value of E'121 is divided by the average value of E'50 to obtain E'121 / E'50 (unit: dimensionless).

[0146] <Apparatus and Conditions>

[0147] Device: EXSTAR DMS6100 (manufactured by Seiko Instruments Co., Ltd.)

[0148] Test mode: Tensile mode

[0149] Chuck spacing: 20mm

[0150] Frequency: 10Hz

[0151] Strain amplitude: 20.0 μm

[0152] Gain: 1.5

[0153] Initial force amplitude: 490mN

[0154] Temperature range: -100~180℃

[0155] Heating rate: 5℃ / minute

[0156] Atmosphere to be measured: air

[0157] Thickness measurement: Use the film thickness from (2) above.

[0158] (4) Thermal shrinkage rate (%) along the main orientation axis at 150℃

[0159] Five samples, each 10 mm wide and 150 mm long (in the measurement direction), were cut along the main orientation axis of the polyolefin film. Each sample was marked 5 mm from both ends, resulting in a test length of 100 mm (l0). The test pieces were then sandwiched between pieces of paper and heated in an oven at 150°C for 10 minutes while remaining horizontal. After cooling at 23°C, the dimension (l1) was measured, and the average value of the five samples was used as the heat shrinkage rate in each direction. Heat shrinkage rate = {(l0-l1) / l0} × 100 (%).

[0160] (5) Elongation at break (%) in the direction orthogonal to the principal orientation axis

[0161] A rectangular polyolefin film or laminate (width (short side) 10 mm × length (long side) 150 mm) cut along its long side (orthogonal to the main orientation axis determined above) was used as the test specimen. Next, a tensile testing machine (OEIENTEK "Tensilon" (registered trademark) UCT-100) was used, with an initial chuck distance of 20 mm, and a tensile speed of 300 mm / min was set at 23°C. The long side position of the specimen was adjusted so that its center was near the center of the chucks. The elongation (in %) at the moment of fracture was measured. Five measurements were performed, and the average elongation at the fracture point was used to calculate the tensile elongation of the polyolefin film or laminate in the direction orthogonal to the main orientation axis.

[0162] (6) The ratio of tanδ along the principal orientation axis: tanδ50 / tanδ121

[0163] Under the same apparatus and conditions as described in (3) above, the viscoelastic-temperature curve was plotted using the dynamic viscoelastic method, and the storage modulus (E'50) and loss modulus (E”50) at 50°C were read. It should be noted that the test was conducted with a test number of n=3, and the average values ​​of the storage modulus (E'50) and loss modulus (E”50) were calculated. The loss tangent (tanδ50) at 50°C in the direction of the main orientation axis of the membrane was calculated by the following formula.

[0164] Formula: tanδ50=E”50 / E'50

[0165] Similarly, with the number of tests n=3, the storage modulus (E'121) and loss modulus (E”121) at 121℃ are read from the viscoelastic-temperature curve, and their average values ​​are calculated. The loss tangent (tanδ121) at 121℃ in the main orientation axis direction of the film is calculated by the following formula.

[0166] Formula: tanδ121=E”121 / E’121

[0167] Divide the obtained tanδ50 value by the obtained tanδ121 value to get tanδ50 / tanδ121 (unit: dimensionless).

[0168] (7) Gloss

[0169] According to JIS K-7105 (1981), the gloss level of the film surface on the contact side of the casting drum was measured using a digital variable angle gloss meter UGV-5D manufactured by Suga Testing Machine Co., Ltd., under the conditions of an incident angle of 60° and a light reception angle of 60°. The average value of the data obtained from the 5 points was taken as the gloss level (%).

[0170] (8) Melting point (Tm) of the raw material resin composition and the resin composition of each layer of the film.

[0171] As a sample, a substance formed by cutting each layer of a polyolefin film using the raw material resin composition used in the polyolefin resin film of the present invention (in the case of mixing multiple raw materials, it is a resin composition formed by mixing them in a specified proportion) was used. Using a differential scanning calorimeter (Seiko Instrument EXSTAR DSC6220), in a nitrogen atmosphere, 3 mg of the polyolefin resin sample was heated from 30°C to 260°C at a rate of 20°C / min. Then, after holding at 260°C for 5 minutes, it was cooled to 30°C at a rate of 20°C / min. Then, after holding at 30°C for 5 minutes, it was heated from 30°C to 260°C at a rate of 20°C / min. The peak temperature of the endothermic curve obtained during this heating was taken as the melting point of the raw material resin composition and each layer of the film. In this embodiment, (Tm) was calculated from the average value of measurements performed with n=3. It should be noted that when more than two peak temperatures are observed in the range of more than 130°C and less than 260°C, or when a peak temperature can be observed in a multi-level DSC chart known as a shoulder peak (in the case of a chart where more than two peaks overlap), in this embodiment, the temperature of the peak with the largest absolute value of the vertical axis heat flux (unit: mW) of the DSC chart is taken as the melting point (Tm) (°C).

[0172] (9) The number of regions of cyclic olefin resin passing through a pair of sides parallel to the thickness direction in a 1μm×2μm rectangle in layer A (number / 2μm) 2 )

[0173] Using a dicing method, layer A of a polyolefin film is cut with a plane parallel to both the main orientation axis and the thickness direction to form a polypropylene film sheet with a cut surface. After staining the cut surface with RuO4, the stained surface is cut to collect an ultrathin section with section X. The collected ultrathin sections are then observed using a transmission electron microscope (TEM) under the following conditions. It should be noted that, in this case, cyclic olefin resins stain darker than polypropylene resins.

[0174] • Apparatus: HT7700 transmission electron microscope (TEM) manufactured by Hitachi, Ltd.

[0175] Accelerating voltage: 100kV

[0176] Observation magnification: 2,000x

[0177] In the images acquired during the above observations, a 2μm bounding box was drawn. 2A rectangular area, defined by a pair of sides of 1 μm in the thickness direction and 2 μm in the direction perpendicular to the thickness direction, is used to count the number of cyclic olefin resin regions within this rectangle that pass through the pair of sides parallel to the thickness direction. This same measurement is performed a total of 10 times, changing the position of the rectangle within the image. The average number of regions is calculated, and the value is rounded to one decimal place. This average value is then used to calculate the number of cyclic olefin resin regions in layer A that pass through the pair of sides parallel to the thickness direction (regions / 2 μm). 2 It should be noted that when defining a rectangle within section X with a pair of sides of 1 μm in the thickness direction and 2 μm in the direction orthogonal to the thickness direction, the bottom edge of this rectangle is designated as the sea portion. If a region is located on the edge opposite to the bottom edge, it is considered non-existent and not counted. Furthermore, regions with necks are also treated as cyclic olefin resin regions with a more concentrated dyeing density than the polypropylene resin portion of the sea portion, and are treated as connecting regions.

[0178] (10) The height of the ten-point region of the surface (S10z) measured using a three-dimensional non-contact surface shape measuring instrument.

[0179] The S10z value was measured using a Hitachi Hightech Symmetry VS1540 scanning white interferometer microscope, which is used as a three-dimensional non-contact surface shape measuring instrument. During analysis, the accompanying analysis software was used to perform a polynomial fourth-order approximate surface correction on the captured image to remove fluctuation components. Then, after processing with a median (3×3) filter, interpolation was performed (for pixels where height data was unavailable, compensation was made using height data calculated from surrounding pixels). The measurement conditions are described below. It should be noted that when layer B is located on two surfaces, measurements were performed on both surfaces, and the lower value was used.

[0180] Manufacturer: Hitachi High-tech Co., Ltd.

[0181] Device Name: Scanning White Interference Microscope VS1540

[0182] Measurement conditions: 10× objective lens

[0183] 1× lens tube

[0184] 1× zoom lens

[0185] 530nm white wavelength filter

[0186] • Measurement mode: Wave

[0187] • Measurement software: VS-Measure Version 10.0.4.0

[0188] ·Analysis software: VS-Viewer version 10.0.3.0

[0189] ·Analysis condition: S-Filter = 5 μm

[0190] ·Measured area: 0.561 × 0.561 [mm 2 .

[0191] (11) Heat sealability

[0192] Overlay the C-layer surface of the film (in the case of no C-layer, the surface opposite to the evaporation side) with a stretched PET film having a thickness of 12 μm, and perform heat sealing under the following conditions using a flat heat sealer to produce a laminated product. Use "Tensilon" (registered trademark) manufactured by Orientec Co., Ltd. to conduct a T-shaped peel test on the interface between the polyolefin film of the present invention and the stretched PET film, and measure the heat seal strength. It should be noted that the laminated product for the peel test is sampled in a short strip shape with a width of 20 mm × a length of 150 mm, and the heat seal strength is measured at a stretching speed of 300 mm / min. This measurement is performed 3 times, and the average value of the obtained values is calculated, and the obtained value is used as the heat seal strength (N / 25.4 mm). When the heat seal strength can reach 2 N / 25.4 mm or more, it is determined that the heat sealability is qualified (A), and if it is less than 2 N / 25.4 mm, it is determined that the heat sealability is unqualified (B).

[0193] <Heat seal conditions>

[0194] ·Pressing pressure: 0.4 N / mm 2

[0195] ·Pressing time: 1 second

[0196] ·Heater temperature: 120 °C.

[0197] (12) Water vapor barrier property after Al evaporation or AlOx evaporation

[0198] <Method of Al evaporation>

[0199] Install a film roll in a vacuum evaporation apparatus equipped with a film moving device, form a high vacuum state of 1.00 × 10 -2 Pa, and while heating and evaporating aluminum metal on a cooling metal drum at 20 °C, move the film to form an evaporated thin film layer on the B layer. At this time, it is controlled so that the thickness of the evaporated film becomes 100 nm. After evaporation, restore the inside of the vacuum evaporation apparatus to normal pressure, rewind the wound film, and age it at a temperature of 40 °C for 2 days to obtain a laminate having an Al (aluminum) evaporated layer laminated on the film.

[0200] <Method of AlOx evaporation>

[0201] A film roller is installed in a vacuum evaporation device equipped with a film traveling device to form a 1.00×10⁻⁶ film. -2 After a high-pressure reduction of Pa, oxygen is introduced into a cooled metal drum at 20°C to allow AlOx to react and evaporate while the film is moved, forming a vapor-deposited layer on the previously corona-treated surface. The thickness of the vapor-deposited layer is controlled to 20 nm. After vapor deposition, the vacuum vapor deposition apparatus is restored to atmospheric pressure, the wound film is rewound, and cured at 40°C for 2 days to obtain a laminate with an AlOx (alumina) vapor-deposited layer laminated on the film.

[0202] <Evaluation Methods for Water Vapor Barrier Properties>

[0203] For laminates subjected to Al or AlOx vapor deposition, the water vapor transmission rate was measured using a MOCON / Modern Controls PERMATRAN-W (registered trademark) 3 / 30 water vapor transmission rate measuring device at 40°C and 90% RH. The measurement was performed five times for each sample, and the average value was calculated as the water vapor transmission rate of the film (unit: g / m). 2 ( / day). Based on the obtained water vapor transmission rate, the water vapor barrier properties of the laminate are determined according to the following criteria. A rating of B or higher is considered good water vapor barrier properties, and C is considered a level that poses no practical problem.

[0204] S: 0.3g / m 2 / day or less.

[0205] A: Greater than 0.3g / m 2 / day and 0.5g / m 2 / day or less.

[0206] B: Greater than 0.5g / m 2 / day and 1.0g / m 2 / day or less.

[0207] C: greater than 1.0 g / m 2 / day and 2.0g / m 2 / day or less.

[0208] D: Greater than 2.0 g / m 2 / day, or the film may break during the vapor deposition process.

[0209] (13) Ox barrier properties after Al vapor deposition or AlOx vapor deposition

[0210] Using the method described in (12), a laminate containing an Al vapor-deposited layer or an AlOx vapor-deposited layer was obtained. For each laminate, the oxygen permeability was measured using an oxygen permeability measuring device "OX-TRAN" (registered trademark) 2 / 20 manufactured by MOCON / Modern Controls at a temperature of 23°C and a humidity of 0%RH. The measurement was performed 5 times for each sample, and the average value was calculated as the oxygen permeability of the film (unit: cc / m). 2 ( / day). Based on the obtained oxygen permeability, the oxygen barrier properties of the laminate are determined according to the following criteria. A rating of B or higher is considered good oxygen barrier properties, and C is considered a level with no practical problems.

[0211] S: 1.5cc / m 2 / day or less.

[0212] A: Greater than 1.5cc / m 2 / day and 2.0cc / m 2 / day or less.

[0213] B: Greater than 2.0cc / m 2 / day and 10cc / m 2 / day or less.

[0214] C: Greater than 10cc / m 2 / day and 100cc / m 2 / day or less.

[0215] D: Greater than 100cc / m 2 / day, or the film broke during the vapor deposition process.

[0216] (14) Thickness of layer D

[0217] The thickness of the D layer constituting the laminate of the present invention was determined by cross-sectional observation using a transmission electron microscope (TEM). A sample for cross-sectional observation was prepared using a micro-sampling system (Hitachi, Ltd. FB-2000A) via the FIB method (specifically, based on the method described in "Polymer Surface Processing" (by Akira Iwamori), pp. 118-119). Next, the cross-section of the sample was observed using a transmission electron microscope (Hitachi, Ltd. H-9000UHRII) with the accelerating voltage set to 300 kV. The thickness of the D layer was confirmed at 10 arbitrary points using the length measurement function of the transmission electron microscope. The arithmetic mean of these measurements was taken as the thickness of the D layer (unit: nm).

[0218] (15) Average height of the prominent peaks on the surface of layer D (Spk)

[0219] The Spk value was measured using a Hitachi Hightech Sciences VS1540 scanning white interferometer, which is used as a three-dimensional non-contact surface shape measuring instrument. In the analysis, the accompanying software was used to remove fluctuation components by performing a polynomial fourth-order approximate surface correction on the captured image. Then, after processing with a median (3×3) filter, interpolation was performed (for pixels where height data was unavailable, compensation was made using height data calculated from surrounding pixels). The measurement conditions are described below.

[0220] Manufacturer: Hitachi High-tech Co., Ltd.

[0221] Device Name: Scanning White Interference Microscope VS1540

[0222] Measurement conditions: 10× objective lens

[0223] 1× lens tube

[0224] 1× zoom lens

[0225] 530nm white wavelength filter

[0226] • Measurement mode: Wave

[0227] • Measurement software: VS-Measure Version 10.0.4.0

[0228] Analysis software: VS-Viewer version 10.0.3.0

[0229] • Measurement area: 0.561 × 0.561 mm 2 ].

[0230] (16) Evaluation of film capacitor characteristics (voltage withstand and reliability at 135℃)

[0231] On one side of the film (it should be noted that when the wetting tension is different on the front and back sides, the side with higher wetting tension is used), vapor-deposited film A and vapor-deposited film B are respectively fabricated. Vapor-deposited film A is obtained by vapor-depositing aluminum with a film resistance of 10Ω / sq and blank areas in the direction perpendicular to the length direction, forming a so-called T-shaped blank (using masking oil, the length direction spacing (period) is 17mm, and the fuse width is 0.5mm). Vapor-deposited film B is a vapor-deposited film without the T-shaped blank vapor-deposited pattern. The above vapor-deposited films A and B are cut separately to obtain vapor-deposited rolls A and B with a film width of 50mm (end blank width is 2mm). Next, using an alternating stacking of vapor deposition rolls A and B, a component winding machine (KAW-4NHB) manufactured by (Kaito Corporation) was used to wind the capacitor elements to a capacitance of 10μF. After metal sputtering, a heat treatment was performed at 128°C under reduced pressure for 12 hours. Leads were then installed to form the capacitor elements. Ten capacitor elements obtained in this way were used, and a voltage of 150VDC was applied to the capacitor elements at a high temperature of 135°C. After 10 minutes at this voltage, the applied voltage was slowly increased in steps of 50VDC / 1 minute, and the above operation was repeated in a so-called step voltage increase test.

[0232] <Voltage Withstand Performance Evaluation>

[0233] In the stepped voltage test, the change in capacitance was measured and plotted on a graph. The withstand voltage was determined by dividing the voltage at which the capacitance became 70% of the initial value by the thickness of the film (as described in (1)). The average value of 10 capacitor elements was calculated and evaluated according to the following criteria: A indicates usability, and B indicates poor practical performance.

[0234] A: Above 320V / μm

[0235] B: Less than 320V / μm.

[0236] <Reliability Evaluation>

[0237] After the voltage is increased until the electrostatic capacitance decreases to less than 12% of its initial value, the capacitor element with the highest voltage withstand capability among the 10 capacitor elements is disassembled, and the state of failure is investigated. The reliability is evaluated as follows: A indicates usable, and B indicates poor practical performance.

[0238] A: The component shape remains unchanged, and penetrating damage to one or more layers of the inner film is observed. Alternatively, no change in component shape or penetrating damage is observed.

[0239] B: Confirm the change in component shape, or observe penetrating damage exceeding 10 layers.

[0240] [Resins, etc.]

[0241] In the manufacture of the polyolefin films in the various embodiments and comparative examples, the following resins and the like were used.

[0242] (Layer A uses polypropylene resin)

[0243] A1: Homopolymer polypropylene resin (Plain Polymer Co., Ltd. "F133A" (meta-race five-unit component ratio: 0.973, melting point: 165℃, MFR = 3.0 g / 10min)

[0244] A2: Homopolymer polypropylene resin (Plain Polymer Co., Ltd. "F113G" (meta-race five-unit component ratio: 0.940, melting point: 162℃, MFR: 2.9g / 10min)

[0245] (Layer B uses polypropylene resin)

[0246] B1: Homopolymer polypropylene resin (Plain Polymer Co., Ltd. "F113G" (meta-race five-unit component ratio: 0.940, melting point: 162℃, MFR: 2.9g / 10min)

[0247] B2: Homopolymer polypropylene resin (Plain Polymer Co., Ltd. "F133A" (meta-race five-unit component ratio: 0.973, melting point: 165℃, MFR = 3.0 g / 10min)

[0248] (C layer uses polypropylene resin)

[0249] C1: Ethylene-propylene random copolymer (manufactured by Polypro Co., Ltd. of Japan, “WFW4M”, melting point: 135℃, MFR=7.0g / min).

[0250] <Ingredients other than polypropylene resins>

[0251] Cyclic olefin resins:

[0252] COC1: Polyplastics "TOPAS" (registered trademark) 6013F-04 (a resin (COC) copolymerized from ethylene and norbornene, with a glass transition temperature of 138°C)

[0253] COC2: Mitsui Chemicals manufactures "APEL" (registered trademark) 5014CL (a resin (COC) copolymerized from ethylene and norbornene derivatives, with a glass transition temperature of 136°C).

[0254] Antioxidants:

[0255] Ciba Specialty Chemicals manufactures "IRGANOX" (registered trademark) 1010.

[0256] <Thermoplastic resins incompatible with polypropylene resins>

[0257] Polymethylpentene resin (PMP):

[0258] Mitsui Chemicals Co., Ltd. manufactures "TPX" (registered trademark) (RT31, melting point: 232℃, MFR: 9g / 10min@260℃).

[0259] <Masterbatch for Layer A>

[0260] Polyolefin resin raw material (AM1):

[0261] The components were mixed in such a manner that polypropylene resin (A1) was 69.5 parts by mass, cyclic olefin resin (COC1) was 30 parts by mass, and antioxidant was 0.5 parts by mass. The mixture was then extruded using a twin-screw extruder set to 260°C. The filament was then water-cooled and fragmented to produce polyolefin resin raw material (AM1).

[0262] Polyolefin resin raw material (AM2):

[0263] The components are mixed in such a way that polypropylene resin (A2) is 69.5 parts by mass, cyclic olefin resin (COC1) is 30 parts by mass, and antioxidant is 0.5 parts by mass. After mixing and extruding in a twin-screw extruder set to 260°C, the filament is water-cooled and fragmented to produce polyolefin resin raw material (AM2).

[0264] Polyolefin resin raw material (AM3):

[0265] The components were mixed in such a manner that polypropylene resin (A1) was 69.5 parts by mass, cyclic olefin resin (COC2) was 30 parts by mass, and antioxidant was 0.5 parts by mass. The mixture was then extruded using a twin-screw extruder set to 260°C. The filament was then water-cooled and fragmented to produce polyolefin resin raw material (AM3).

[0266] <Masterbatch for Layer B>

[0267] Polyolefin resin raw materials (BM1)

[0268] The components are mixed in such a manner that polypropylene resin (B1) is 69.5 parts by mass, polymethylpentene resin (PMP) is 30 parts by mass, and antioxidant is 0.5 parts by mass. After mixing and extruding in a twin-screw extruder set to 260°C, the filament is water-cooled and fragmented to produce polyolefin resin raw material (BM1).

[0269] (Example 1)

[0270] The components are mixed in a manner that makes 32 parts by mass of polyolefin resin raw material (AM1), 67.6 parts by mass of polypropylene resin (A1), and 0.4 parts by mass of antioxidant, and then fed to a single-screw melt extruder for layer A. Polypropylene resin B1 is fed to a single-screw melt extruder for layer B, and polypropylene resin C1 is fed to a single-screw melt extruder for layer C. Here, the oxygen concentration in the feed hopper of each extruder is controlled at 0.05%. After melt extrusion at 260°C using each extruder, foreign matter is removed from the extruded molten resin using a sintered filter with an 80μm cutoff. Then, using a distributor, a three-layer structure with a layer structure of b / a / c is formed at a temperature of 250°C (the compositions used for the molten layers B, A, and C are designated as b, a, and c, respectively). The lamination ratio is 1 / 10 / 1 (layer A contains 9.6% cyclic olefin resin by mass, and the thickness ratio of layer A to the overall film is approximately 83%, therefore the overall film contains 8.0% cyclic olefin resin by mass). The lamination ratio is adjusted by regulating the extrusion rate from each extruder. The laminated molten resin is then introduced into a T-die and discharged as a sheet at 240°C. The discharged molten sheet is cooled and solidified on a casting drum maintained at 21°C to obtain an unstretched sheet. It should be noted that at this point, b is brought into contact with the casting drum, and air is blown from an air knife at a controlled temperature of 40°C to ensure a tight seal between the molten sheet and the casting drum.

[0271] Next, the unstretched polyolefin film is preheated in stages to 145°C using multiple roller sets. Then, it is stretched 5.2 times its original length through a roller bed maintained at 155°C with a circumferential speed difference. The stretched film is then cooled through a roller bed maintained at 70°C, and finally cooled to room temperature to obtain a uniaxially oriented film. The obtained uniaxially oriented film is then fed into a tenter frame, preheated to 165°C while the two ends in the width direction are held by clamps, stretched 9.2 times its original length at 158°C in the width direction, and then heat-treated at 162°C while allowing 12% relaxation in the width direction. Then, while the two ends in the width direction are still held by clamps, the film is guided to the outside of the tenter frame after a cooling process at 140°C, and the clamps at the two ends in the width direction are released. Next, the film surface (the B-layer side, which becomes the contact surface with the casting drum) is heated at 25 W·min / m. 2The polyolefin film was subjected to corona discharge treatment in a mixed gas atmosphere of carbon dioxide and nitrogen at a volume ratio of 15:85 (with an oxygen concentration of 0.8% by volume). The resulting polyolefin film was then wound onto a roller. Next, the polyolefin film was unwound from the roller, and the corona-treated surface was subjected to Al vapor deposition using the method described above, resulting in a laminate with an Al vapor-deposited layer (D layer). The characteristics of the obtained polyolefin film and laminate are shown in Table 1.

[0272] (Example 2)

[0273] AlOx was deposited instead of Al to form a laminate with an AlOx layer (D layer). Otherwise, the polyolefin film and laminate were prepared in the same manner as in Example 1. The properties of the obtained polyolefin film and the laminate with the deposited D layer are shown in Table 1. It should be noted that the AlOx deposition was performed using the aforementioned method.

[0274] (Example 3)

[0275] The polyolefin film prepared in Example 2 was crushed and compressed using a crusher, and then fed into an extruder where the oxygen concentration in the hopper was controlled at 0.05% and the temperature was set at 240°C for mixing and extrusion. After the filament was water-cooled, it was fragmented to obtain recycled granules (AR1). Next, A1, AM1, and AR1, which are polyolefin resin raw materials used for layer A, were mixed in a mass ratio of 53:27:20 and fed to a single-screw melt extruder for layer A. Polypropylene resin B1 was fed to a single-screw melt extruder for layer B, and polypropylene resin C1 was fed to a single-screw melt extruder for layer C. Here, the oxygen concentration in the feed hopper of each extruder was controlled to 0.05%, and melt extrusion was performed using each extruder at a temperature of 260°C. The film-forming conditions were set as shown in Table 1 (the cyclic olefin content in layer A is 9.7% by mass, the thickness ratio of layer A to the overall film is 83%, therefore the cyclic olefin content in the overall film is 8.1% by mass). Otherwise, a polyolefin film and a laminate with a vapor-deposited layer D were prepared in the same manner as in Example 2. The characteristics of the obtained polyolefin film and the laminate with a vapor-deposited layer D are shown in Table 1.

[0276] (Example 4)

[0277] The layer structure was set to B / A / B, with polypropylene resin B2 used for layer B. The film-forming conditions were set as shown in Table 1. Otherwise, the same procedures as in Example 2 were performed to fabricate a polyolefin film and a laminate with layer D deposited on it. The characteristics of the resulting polyolefin film and the laminate with layer D deposited on it are shown in Table 1. It should be noted that the vapor deposition was performed on the side of layer B that is in contact with the casting drum.

[0278] (Example 5)

[0279] The layer structure was set to B / A / B. The components were mixed such that the polyolefin resin raw material (AM2) was 63 parts by mass, the polypropylene resin (A1) was 36.6 parts by mass, and the antioxidant was 0.4 parts by mass. The mixture was then fed into a single-screw melt extruder for layer A. The lamination ratio and film-forming conditions were set as shown in Table 1. Otherwise, a polyolefin film and a laminate with a vapor-deposited layer D were prepared in the same manner as in Example 2. The characteristics of the resulting polyolefin film and the laminate with a vapor-deposited layer D are shown in Table 1. It should be noted that vapor deposition was performed on the B layer side, which is in contact with the casting drum.

[0280] (Example 6)

[0281] The layer structure was made into a single A layer. The components were mixed in the following manner: 66.7 parts by weight of polyolefin resin raw material (AM1), 32.6 parts by weight of polypropylene resin (Al), and 0.4 parts by weight of antioxidant. This mixture was fed into a single-screw melt extruder for the A layer. The film-forming conditions are shown in Table 1. Except for this, a polyolefin film and a laminate with a vapor-deposited D layer were prepared in the same manner as in Example 2. The characteristics of the resulting polyolefin film and the laminate with the vapor-deposited D layer are shown in Table 1. It should be noted that vapor deposition was performed on the surface in contact with the casting drum.

[0282] (Example 7)

[0283] As layer B in Example 2, the components were mixed and fed into a single-screw melt extruder for layer B, with 95.6 parts by mass of polyolefin resin raw material (B1), 4 parts by mass of polyolefin resin raw material (BM1), and 0.4 parts by mass of antioxidant. As layer A, the components were mixed and fed into a single-screw melt extruder for layer A, with 28.6 parts by mass of polyolefin resin raw material (AM1), 67.6 parts by mass of polypropylene resin (A1), and 0.4 parts by mass of antioxidant (the cyclic olefin resin contained in layer A is 8.6% by mass, and the thickness ratio of layer A to the overall film is approximately 83%, therefore the cyclic olefin resin contained in the overall film is 7.1% by mass). The film-forming conditions were set as shown in Table 1. Otherwise, a polyolefin film and a laminate with layer D deposited were prepared in the same manner as in Example 2. The characteristics of the obtained polyolefin film and the laminate with layer D deposited are shown in Table 1. It should be noted that vapor deposition is performed on the surface that contacts the casting drum.

[0284] (Example 8)

[0285] As layer B in Example 2, the components were mixed and fed into a single-screw melt extruder for layer B, with 87.6 parts by mass of polyolefin resin raw material (B1), 12 parts by mass of polyolefin resin raw material (BM1), and 0.4 parts by mass of antioxidant. As layer A, the components were mixed and fed into a single-screw melt extruder for layer A, with 28.6 parts by mass of polyolefin resin raw material (AM1), 67.6 parts by mass of polypropylene resin (A1), and 0.4 parts by mass of antioxidant. The film-forming conditions were set as shown in Table 1. Except for this, a laminate of polyolefin film and layer D deposited was prepared in the same manner as in Example 2. The characteristics of the obtained polyolefin film and laminate of layer D deposited are shown in Table 1. It should be noted that vapor deposition is performed on the surface in contact with the casting drum.

[0286] (Example 9)

[0287] Using a polyolefin resin raw material (AM3) as layer A in Example 8, the film-forming conditions were set as shown in Table 1. Otherwise, the polyolefin film and the laminate with layer D were prepared in the same manner as in Example 8. The characteristics of the resulting polyolefin film and the laminate with layer D are shown in Table 1. It should be noted that the vapor deposition was performed on the surface in contact with the casting drum.

[0288] (Example 10)

[0289] To achieve a film thickness of 3.1 μm, the components were mixed in the following manner: 28.6 parts by weight of polyolefin resin raw material (AM1) for layer A, 67.6 parts by weight of polypropylene resin (A1), and 0.4 parts by weight of antioxidant. The mixture was then fed into a single-screw melt extruder for layer A, and the film-forming conditions were as shown in Table 1. Except for these conditions, the polyolefin film was prepared in the same manner as in Example 4. The capacitor characteristics of the prepared film are shown in Table 1.

[0290] (Example 11)

[0291] As layer A of Example 10, a polyolefin resin raw material (AM3) was used, and the film-forming conditions were set as shown in Table 1. Otherwise, the polyolefin film was prepared in the same manner as in Example 10. The capacitor characteristics of the prepared film are shown in Table 1.

[0292] (Comparative Example 1)

[0293] In layer A, only polypropylene resin A1 is used without masterbatch. The film-forming conditions are set as shown in Table 2. Otherwise, a polyolefin film and a laminate with layer D are prepared in the same manner as in Example 2. The characteristics of the resulting polyolefin film and the laminate with layer D are shown in Table 2.

[0294] (Comparative Example 2)

[0295] The layer structure was set as B / A / B. No masterbatch was used in layer A. The components were mixed in a manner that yielded 90 parts by weight of polypropylene resin A1, 9.6 parts by weight of cyclic olefin resin, and 0.4 parts by weight of antioxidant, and fed to a single-screw melt extruder for layer A. Polypropylene resin B2 was used in layer B. The film-forming conditions were set as shown in Table 2. Except for this, a polyolefin film and a laminate with a vapor-deposited layer D were prepared in the same manner as in Example 2. The characteristics of the resulting polyolefin film and the laminate with a vapor-deposited layer D are shown in Table 2. It should be noted that vapor deposition was performed on the side of layer B, which is in contact with the casting drum.

[0296] (Comparative Example 3)

[0297] The film-forming conditions and lamination ratios were set as shown in Table 2. Otherwise, the polyolefin film and the laminate with the D layer were prepared in the same manner as in Example 2. The characteristics of the resulting polyolefin film and the laminate with the D layer are shown in Table 2.

[0298] (Comparative Example 4)

[0299] The oxygen concentration in the raw material feed hopper was set to 10%, and the extrusion temperature was set to a constant 260°C instead of a multi-stage cooling process with gradual temperature reduction from the extruder to the T-die. The film-forming conditions were set as shown in Table 2. Otherwise, a polyolefin film and a laminate with a D-layer were prepared in the same manner as in Example 4. The characteristics of the resulting polyolefin film and the laminate with the D-layer are shown in Table 2. It should be noted that the vapor deposition was performed on the B-layer side, which is in contact with the casting drum.

[0300] (Comparative Example 5)

[0301] The laminate structure was set as B / A / B, and the laminate thickness ratio was set as 1 / 8 / 1. For layer A, the components were mixed such that the polyolefin resin raw material (AM2) was 63 parts by mass, the polypropylene resin (A1) was 36.6 parts by mass, and the antioxidant was 0.4 parts by mass. The mixture was then fed into a single-screw melt extruder for layer A. The film-forming conditions without biaxial stretching are shown in Table 2. Otherwise, the polyolefin film and the laminate with layer D were prepared in the same manner as in Example 4. The characteristics of the resulting polyolefin film and the laminate with layer D are shown in Table 2. It should be noted that the vapor deposition was performed on the side of layer B, which is in contact with the casting drum.

[0302] (Comparative Example 6)

[0303] The membrane thickness was set to 3.1 μm, and the membrane fabrication conditions were set as shown in Table 2. Otherwise, the polyolefin membrane was fabricated in the same manner as in Example 4. The characteristics of the fabricated polyolefin membrane and the thin-film capacitor are shown in Table 2.

[0304] (Comparative Example 7)

[0305] The membrane thickness was set to 3.1 μm, and the membrane fabrication conditions were set as shown in Table 2. Otherwise, the polyolefin membrane was fabricated in the same manner as in Comparative Example 2. The capacitor characteristics of the fabricated membrane are shown in Table 2.

[0306]

[0307]

[0308] Industrial availability

[0309] According to the present invention, a polyolefin film can be provided that can mitigate the decrease in structural stability, water vapor barrier properties, and oxygen barrier properties associated with heating. Because the polyolefin film of the present invention possesses the above-mentioned properties, it is suitable for packaging applications where films are easily degraded by water vapor and oxygen.

[0310] Symbol Explanation

[0311] A portion of section X

[0312] 2 Sea Section

[0313] Part of the 3 islands (area)

[0314] 4. A rectangle with dimensions of 1μm × 2μm defined within section X, with a pair of sides parallel to the thickness direction.

[0315] 5. A pair of sides parallel to the thickness direction

Claims

1. A polyolefin membrane, characterized in that, It is a biaxially oriented film. When the storage modulus of the main orientation axis at 50°C and 121°C, obtained by dynamic viscoelasticity measurement at a frequency of 10Hz, is set to E'50 (Pa) and E'121 (Pa), respectively, E'121 / E'50 is greater than 0.25 and less than 0.99, the thermal shrinkage rate of the main orientation axis at 150°C is greater than -2% and less than 10%, and the tensile elongation rate in the direction orthogonal to the main orientation axis is greater than 20% and less than 300%. It also has at least one layer A, which contains cyclic olefin resin and polypropylene resin, and the A layer has an island structure.

2. A polyolefin film, which is a biaxially oriented film, having at least one layer A comprising a cyclic olefin resin and a polypropylene resin, wherein when the cross section of the A layer is cut using a plane parallel to the main orientation axis and the thickness direction is defined as section X, in a rectangle of size 1 μm × 2 μm within section X, defined with a pair of short sides parallel to the thickness direction, there are two or more regions of the cyclic olefin resin passing through the pair of short sides, and when the storage modulus in the main orientation axis direction at 50°C and 121°C, obtained by dynamic viscoelasticity measurement at a frequency of 10 Hz, is set as E'50 (Pa) and E'121 (Pa), respectively, E'121 / E'50 exceeds 0.20 and is less than 0.99, wherein the A layer has an island structure.

3. In the polyolefin membrane according to claim 1 or 2, when the tanδ of the main orientation axis direction at 50°C and 121°C, obtained by dynamic viscoelasticity measurement at a frequency of 10 Hz, is set to tanδ50 and tanδ121 respectively, the ratio of tanδ50 / tanδ121 exceeds 0.25 and is less than 0.

99.

4. In the polyolefin membrane according to claim 1 or 2, when the layer with polypropylene resin as the main component and the content of cyclic olefin resin is lower than that of layer A is designated as layer B, layer B is present on at least one surface of layer A.

5. In the polyolefin film according to claim 4, when the layer with a melting point lower than that of layers A and B, and a melting point above 100°C and below 150°C is designated as layer C, layer B is located on one outermost surface and layer C is located on the other outermost surface.

6. The polyolefin membrane according to claim 4, wherein the height S10z of the ten-point region of at least one surface of the B layer, as measured by a three-dimensional non-contact surface shape measuring instrument, is 150 nm or more and 900 nm or less.

7. The polyolefin film according to claim 4, wherein the B layer comprises 1% by mass and 10% by mass of a thermoplastic resin incompatible with polypropylene resin.

8. The polyolefin membrane according to claim 1 or 2, comprising at least one of metal particles and inorganic compound particles.

9. The polyolefin membrane according to claim 8, wherein the inorganic compound particles comprise at least one of alumina, silicon dioxide, and oxides of aluminum and silicon.

10. The polyolefin membrane according to claim 1 or 2, wherein polypropylene resin is the main component.

11. The polyolefin film according to claim 1 or 2, wherein at least one film surface has a gloss level of more than 130% and less than 160%.

12. The polyolefin membrane according to claim 1 or 2, wherein the meso-pentameric component ratio of the polypropylene resin is 0.90 or higher.

13. The polyolefin film according to claim 1 or 2, comprising a cyclic olefin resin having a glass transition temperature of 125°C or higher and 200°C or lower.

14. A laminate comprising a polyolefin membrane according to any one of claims 1 to 13, and a layer D comprising a total of more than 50% by mass and less than 100% by mass of metals and inorganic compounds.

15. The laminate according to claim 14, wherein the average height Spk of the protruding peaks on the surface of the D layer, as measured by a three-dimensional non-contact surface roughness meter, is 10 nm or more and 400 nm or less.

16. A packaging material comprising at least one of the polyolefin film according to any one of claims 1 to 13, and the laminate according to claim 14 or 15.

17. A bundle body formed by bundling contents using the packaging material of claim 16.

18. A metal film laminate, which is formed by having a metal film on at least one surface of a polyolefin film according to any one of claims 1 to 4, 6, 7, 10 to 13.

19. A thin-film capacitor formed using the metal film laminate of claim 18.

20. A power control unit having the thin-film capacitor of claim 19.

21. An electric vehicle having the power control unit of claim 20.

22. An electric aircraft having the power control unit as claimed in claim 20.

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