Thermoplastic polyolefin-based film

Abstract

The present invention relates to: a thermoplastic polyolefin-based film that is formed from a resin composition containing a thermoplastic polyolefin as a main component, has a storage elastic modulus E' of 50 MPa or greater at 150°C, and has a storage elastic modulus E' of 1 MPa or greater at 270°C; and a method for producing said thermoplastic polyolefin-based film.

Description

Thermoplastic polyolefin film

[0001] The present invention relates to a thermoplastic polyolefin film.

[0002] Thermoplastic polyolefins such as polyethylene and polypropylene are suitable for extrusion-molded products and injection-molded products such as film products, and films formed from thermoplastic polyolefins are widely used. However, common thermoplastic polyolefins such as polyethylene and polypropylene are not suitable for use in higher temperature environments, for example, above 200°C. Therefore, development is underway for plastic films formed from thermoplastic polyolefins that can be used in higher temperature environments. For example, Patent Document 1 discloses a thermoplastic polyolefin having a melt viscosity of 1×10 measured under conditions of 330°C and a shear rate of 0.1 (1 / sec). ４ Patent Document 2 discloses a stretched film obtained by stretching an unstretched film formed from a homopolymer of 3-methylbutene-1 or a copolymer of 3-methylbutene-1 and an α-olefin and / or polyene having 2 to 12 carbon atoms, having a viscosity of 0.05 poise or more, at a stretch ratio of 2 or more. Patent Document 2 also discloses a release film comprising a uniaxially stretched film formed from a composition containing 5 to 95 parts by weight of a 3-methyl-1-butene polymer (A) and 5 to 95 parts by weight of a 4-methyl-1-pentene polymer (B) (the total amount of components (A) and (B) is 100 parts by weight), and at least one surface of the uniaxially stretched film is roughened by embossing.

[0003] JP 60-176741 A JP 2002-137231 A

[0004] As mentioned above, in order to enable use in higher temperature environments, better heat resistance is required for films formed from thermoplastic polyolefins. Furthermore, for example, thermoforming films used in compression molding, pressure molding, vacuum molding, etc.; release films for semiconductor encapsulation processes, etc., need to be pressed or sucked against a mold while being heated during molding of a molded product, so that the film conforms to the mold shape. Therefore, they are required to suppress breakage and damage even under high temperature and pressure conditions, and have good mold formability. Therefore, from the perspective of expected expansion into such applications, films formed from thermoplastic polyolefins are also required to have better thermoformability. Therefore, an object of the present invention is to provide a thermoplastic polyolefin film having good heat resistance and thermoformability.

[0005] As a result of extensive research, the present inventors have found that the above-mentioned problems can be solved by producing a thermoplastic polyolefin-based film that satisfies certain requirements. That is, the present invention encompasses the following inventions. [1] A thermoplastic polyolefin-based film formed from a resin composition containing a thermoplastic polyolefin as a main component, having a storage modulus E' of 50 MPa or more at 150°C and a storage modulus E' of 1 MPa or more at 270°C. [2] The thermoplastic polyolefin-based film according to [1] above, having a storage modulus E' of 1,000 MPa or less at 70°C. [3] The thermoplastic polyolefin-based film according to [1] or [2] above, having a surface roughness Ra of 1,000 nm or less. [4] The thermoplastic polyolefin-based film according to any one of [1] to [3] above, having an internal haze of 12.0% or less. [5] The thermoplastic polyolefin-based film according to any one of [1] to [4] above, having a yellowness index (YI) of 3.50 or less. [6] The thermoplastic polyolefin film according to any one of [1] to [5], wherein the thermoplastic polyolefin is a 3-methyl-1-butene polymer. [7] The thermoplastic polyolefin film according to [6], wherein the 3-methyl-1-butene polymer is at least one selected from the group consisting of a 3-methyl-1-butene homopolymer and a copolymer of 3-methyl-1-butene with at least one α-olefin having 3 to 20 carbon atoms other than ethylene and 3-methyl-1-butene. [8] The thermoplastic polyolefin film according to [6] or [7], wherein the content of the 3-methyl-1-butene polymer is 50.0 mass% or more relative to the total amount (100 mass%) of the resin composition. [9] The thermoplastic polyolefin film according to any one of [1] to [8], wherein the resin composition contains an antioxidant.

[10] A method for producing a thermoplastic polyolefin film, comprising: a step (I) of melt-extruding a resin composition containing a thermoplastic polyolefin as a main component, to produce a thermoplastic polyolefin film having a storage modulus E' at 150°C of 50 MPa or more and a storage modulus E' at 270°C of 1 MPa or more.

[11] The method for producing a thermoplastic polyolefin film according to

[10] above, wherein in step (I), the resin composition containing a thermoplastic polyolefin as a main component is melted in an inert atmosphere or in a low-oxygen state.

[12] The method for producing a thermoplastic polyolefin film according to

[10] or

[11] above, wherein in step (I), the resin composition containing a thermoplastic polyolefin as a main component is melted at 280 to 323°C.

[13] The method for producing a thermoplastic polyolefin film according to any one of

[10] to

[12] above, comprising step (II) of contacting the molten extrudate of the resin composition containing a thermoplastic polyolefin as a main component obtained in step (I) with a casting drum, wherein the temperature of the casting drum is 40 to 250°C.

[14] The method for producing a thermoplastic polyolefin film according to any one of

[10] to

[13] , wherein in the step (I), a melt of the resin composition containing the thermoplastic polyolefin as a main component is extruded through a T-die, and a draft ratio [Tt / Ft], which is the ratio of the gap thickness (Tt) of the lip of the T-die to the thickness (Ft) of the resulting thermoplastic polyolefin film, is 1 to 30.

[0006] The present invention also encompasses the following inventions. [1-1] A thermoplastic polyolefin-based film formed from a resin composition containing a thermoplastic polyolefin as a main component, having a storage modulus E' of 50 MPa or more at 150°C and a storage modulus E' of 1 MPa or more at 270°C. [1-2] The thermoplastic polyolefin-based film according to [1-1] above, having a storage modulus E' of 1,000 MPa or less at 70°C. [1-3] The thermoplastic polyolefin-based film according to [1-1] or [1-2] above, having a storage modulus E' of 50 to 500 MPa at 150°C. [1-4] The thermoplastic polyolefin-based film according to any one of [1-1] to [1-3] above, having a storage modulus E' of 1 to 100 MPa at 270°C. [1-5] The thermoplastic polyolefin film according to [1-2] above, having a storage modulus E' at 70°C of 100 to 1,000 MPa. [1-6] The thermoplastic polyolefin film according to any one of [1-1] to [1-5] above, having a yellowness index (YI) of 3.50 or less. [1-7] The thermoplastic polyolefin film according to any one of [1-1] to [1-6] above, wherein the thermoplastic polyolefin is an aliphatic polyolefin. [1-8] The thermoplastic polyolefin film according to any one of [1-1] to [1-7] above, wherein the thermoplastic polyolefin is a 3-methyl-1-butene polymer. [1-9] The thermoplastic polyolefin film according to [1-8] above, wherein the 3-methyl-1-butene polymer is at least one selected from the group consisting of a 3-methyl-1-butene homopolymer and a copolymer of 3-methyl-1-butene with at least one selected from the group consisting of ethylene and an α-olefin having 3 to 20 carbon atoms other than 3-methyl-1-butene. [1-10] The thermoplastic polyolefin film according to [1-8] or [1-9] above, wherein the content of the 3-methyl-1-butene polymer is 50.0 mass% or more relative to 100 mass% of the total amount of the resin composition. [1-11] The thermoplastic polyolefin film according to any one of [1-1] to [1-10] above, wherein the resin composition contains an antioxidant.[1-12] The thermoplastic polyolefin film according to [1-11] above, wherein the antioxidant is at least one selected from the group consisting of phenol-based antioxidants and phosphorus-based antioxidants. [1-13] A method for producing a thermoplastic polyolefin film, comprising step (I) of melt-extruding a resin composition containing a thermoplastic polyolefin as a main component, to produce a thermoplastic polyolefin film having a storage modulus E' of 50 MPa or more at 150°C and a storage modulus E' of 1 MPa or more at 270°C. [1-14] A method for producing a thermoplastic polyolefin film according to [1-13] above, wherein in step (I), the resin composition containing a thermoplastic polyolefin as a main component is melted in an inert atmosphere or in a low-oxygen state. [1-15] A method for producing a thermoplastic polyolefin film according to [1-13] or [1-14] above, wherein in step (I), the resin composition containing a thermoplastic polyolefin as a main component is melted at 280 to 323°C. [1-16] The method for producing a thermoplastic polyolefin film according to any one of [1-13] to [1-15] above, comprising: a step (II) of contacting the molten extrudate of the resin composition containing the thermoplastic polyolefin as a main component obtained in step (I) with a casting drum, wherein the temperature of the casting drum is 40 to 250° C. [1-17] The method for producing a thermoplastic polyolefin film according to any one of [1-13] to [1-16] above, wherein in step (I), the molten resin composition containing the thermoplastic polyolefin as a main component is extruded through a T-die, and a draft ratio [Tt / Ft], which is the ratio of the gap thickness (Tt) of the lip of the T-die to the thickness (Ft) of the resulting thermoplastic polyolefin film, is 1 to 30.

[0007] According to the present invention, it is possible to provide a thermoplastic polyolefin film having good heat resistance and thermoformability.

[0008] The following describes examples of embodiments of the present invention (hereinafter also referred to as "one aspect of the present invention"). However, each embodiment described below is merely an example for embodying the technical concept of the present invention, and the present invention is not limited to the following description. The present invention also includes embodiments in which the details described herein are arbitrarily selected or arbitrarily combined. Although preferred embodiments are described herein, combinations of two or more of the individual preferred embodiments are also preferred. Preferred specifications can be selected arbitrarily; for example, combinations of preferred specifications can be considered more preferable. Unless otherwise specified, the term "XX to YY" used herein as a numerical range means "XX or more and YY or less" (XX represents the lower limit and YY represents the upper limit). For example, simply describing a numerical range as "10 to 90" means a range of 10 or more and 90 or less. In this specification, the lower and upper limits described in stages for numerical ranges (such as each characteristic value, each component content, each structural unit content, each production condition, and values ​​calculated therefrom, each characteristic, and each condition) can be independently combined. For example, from a description of "preferably 10 to 90, more preferably 30 to 60" for the same item, the "preferable lower limit (10)" and the "more preferable upper limit (60)" can be combined to form "10 to 60." Furthermore, for a numerical range, for example, based on the description of "preferably 10 to 90, more preferably 30 to 60," the upper limit can be specified as "10 or more" or "30 or more" without a particular upper limit. Similarly, the upper limit can be specified as "90 or less" or "60 or less" without a particular lower limit. The same applies when the upper end of the numerical range is "less than" or when the lower limit is "over." Similarly, for example, from a description of "preferably 10 or more, more preferably 30 or more" for the same item and "preferably 90 or less, more preferably 60 or less," the "preferable lower limit (10)" and the "more preferable upper limit (60)" can be combined to form "10 or more and 60 or less." Similarly, the lower limit value alone can be specified as "10 or more" or "30 or more," and similarly, the upper limit value alone can be specified as "90 or less" or "60 or less."The same applies when the terms "more than or equal to" and "less than" are written as "more than" and "less than," respectively. For example, based on the description "preferably more than 10 and less than 90, more preferably 30 or more and 60 or less," the upper and lower limits can be combined to form "more than 10 and 60 or less" and "30 or more and less than 90." Furthermore, unless otherwise specified, the terms "storage modulus E'," "flatness (a property evaluated by "curl degree")," "yellowness index (YI)," "surface roughness Ra," "internal haze," "optical properties," "chemical resistance," "heat resistance," "thermoformability," and "handleability" refer to the properties of the thermoplastic polyolefin film of one embodiment of the present invention. These properties are each specifically measured and evaluated by the methods described in the Examples. Furthermore, in this specification, "optical properties" more specifically refer to the properties evaluated by the method described in the "Evaluation as an Optical Film" section of the Examples. However, the "Evaluation as an Optical Film" in the Examples is merely one method for evaluating some of the properties of the thermoplastic polyolefin film of one embodiment of the present invention. In other words, this does not indicate that the use of the thermoplastic polyolefin film of one embodiment of the present invention is limited to optical film use. In addition, in this specification, "handleability" refers to the handleability of the film when it is divided into sheets as described below, and more specifically, refers to the property evaluated by the method described in the "Film Handling Ability" evaluation column in the Examples.

[0009] [Thermoplastic Polyolefin Film] A thermoplastic polyolefin film (hereinafter also referred to as "TPO film") according to one embodiment of the present invention is formed from a resin composition (hereinafter also referred to as "the resin composition") containing a thermoplastic polyolefin as a main component, and has a storage modulus E' at 150°C of 50 MPa or more and a storage modulus E' at 270°C of 1 MPa or more. By satisfying the above-mentioned ranges for the storage modulus E', the TPO film can have good heat resistance and thermoformability. In addition, in this specification, "thermoplastic polyolefin film" refers to a film formed from a resin composition containing the thermoplastic polyolefin as a main component, and includes, for example, a thermoplastic polyolefin film formed when the resin composition consists of only a single thermoplastic polyolefin. In addition, in this specification, the term "contained as a main component" means that the component contained in the resin composition has the largest content by mass.

[0010] From the viewpoint of improving heat resistance, the storage modulus E' at 150 ° C is preferably 70 MPa or more, more preferably 100 MPa or more. From the viewpoint of improving heat resistance and thermoformability, it is even more preferably 120 MPa or more, and even more preferably 140 MPa or more. Being equal to or greater than the lower limit improves thermoformability. Specifically, this is preferable because it can suppress wrinkles due to drawdown of the film during thermoforming and also suppress defects such as uneven thickness of the resulting molded body. Furthermore, from the viewpoint of preventing damage to the film during thermoforming and easily maintaining formability in molds with complex shapes, the storage modulus E' at 150 ° C is preferably 500 MPa or less, and may also be, for example, 400 MPa or less, or 300 MPa or less. As mentioned above, these stepwise lower limit and upper limit values ​​can be independently combined. For example, in one embodiment of the TPO film, the storage modulus E' at 150°C is preferably 50 to 500 MPa, more preferably 70 to 500 MPa, even more preferably 100 to 500 MPa, still more preferably 120 to 500 MPa, and even more preferably 140 to 500 MPa, or may be 50 to 400 MPa, 70 to 400 MPa, 100 to 400 MPa, 120 to 400 MPa, 140 to 400 MPa, 50 to 300 MPa, 70 to 300 MPa, 100 to 300 MPa, 120 to 300 MPa, or 140 to 300 MPa. Furthermore, when the thermoplastic polyolefin is a 3-methyl-1-butene polymer, the higher the storage modulus E' at 150°C, the smaller the values ​​of the surface roughness Ra and internal haze, which will be described later, tend to be.

[0011] From the viewpoint of improving heat resistance, the storage modulus E' at 270°C is preferably 5 MPa or more, more preferably 10 MPa or more. From the viewpoint of improving heat resistance and thermoformability, it is even more preferably 20 MPa or more, and even more preferably 25 MPa or more. Furthermore, the storage modulus E' at 270°C is preferably 100 MPa or less, and may be 80 MPa or less. As described above, these stepwise lower and upper limits can be independently combined. For example, in one embodiment of the TPO-based film, the storage modulus E' at 270°C is preferably 1 to 100 MPa, more preferably 5 to 100 MPa, even more preferably 10 to 100 MPa, even more preferably 20 to 100 MPa, and even more preferably 25 to 100 MPa, or may be 1 to 80 MPa, 5 to 80 MPa, 10 to 80 MPa, 20 to 80 MPa, or 25 to 100 MPa. Furthermore, when the thermoplastic polyolefin is a 3-methyl-1-butene polymer, the higher the storage modulus E' at 270°C, the smaller the surface roughness Ra and internal haze values, which will be described later, tend to be.

[0012] The storage modulus E' of the TPO-based film at 70°C is preferably 1,000 MPa or less, more preferably 900 MPa or less, even more preferably 800 MPa or less, and even more preferably 700 MPa or less. Having a storage modulus E' below the upper limit is preferable because, for example, the film has better flexibility and can prevent cracking during film transport during post-processing, etc., thereby improving the film's handleability. Furthermore, from the viewpoint of improving heat resistance and improving the film's storage stability even in higher temperature environments, the storage modulus E' of the TPO-based film at 70°C is preferably 100 MPa or more, more preferably 250 MPa or more, and even more preferably 300 MPa or more. From the viewpoint of improving heat resistance and thermoformability, it is even more preferably 350 MPa or more, and even more preferably 400 MPa or more. As mentioned above, these stepwise lower and upper limits can be independently combined. For example, in one embodiment of the TPO-based film, the storage modulus E' at 70°C is preferably 100 to 1,000 MPa, more preferably 250 to 900 MPa, even more preferably 300 to 900 MPa, still more preferably 350 to 800 MPa, and even more preferably 400 to 700 MPa. Furthermore, when the thermoplastic polyolefin is a 3-methyl-1-butene-based polymer, the higher the storage modulus E' at 70°C, the smaller the values ​​of the surface roughness Ra and internal haze, which will be described later, tend to be. As described above, the storage modulus E' at 70°C, the storage modulus E' at 150°C, and the storage modulus E' at 270°C of the TPO-based film can be measured, specifically, by the methods described in the Examples section below.

[0013] Furthermore, the storage modulus E' at 270°C, the storage modulus E' at 150°C, and the storage modulus E' at 70°C of the TPO-based film can be adjusted, for example, by the following method. For example, each storage modulus E' can also be adjusted by the components contained in the resin composition. For example, when the storage modulus value at each temperature of the thermoplastic polyolefin contained in the resin composition is larger, each storage modulus E' tends to be larger. On the other hand, when the storage modulus value at each temperature of the thermoplastic polyolefin contained in the resin composition is smaller, each storage modulus E' tends to be smaller. For example, in one embodiment of the present invention, when the resin composition contains an alkyl radical scavenger as described below, each storage modulus E' tends to be larger than when the resin composition does not contain an alkyl radical scavenger. For example, in one embodiment of the present invention, when the resin composition contains an antioxidant as described below, each storage modulus E' tends to be larger than when the resin composition does not contain an antioxidant.

[0014] The storage moduli E' can also be adjusted by the molding conditions of the TPO film. For example, in one embodiment of the present invention, when the TPO film is molded using the thermoplastic polyolefin film manufacturing method of one embodiment of the present invention described below, the storage moduli E' can be increased by adjusting the temperature at which the resin composition is melted in step (I) to a lower temperature within a temperature range at which the resin composition can be sufficiently melted and a film can be formed. For example, by melting the resin composition in an inert atmosphere or a low-oxygen state in step (I), the storage moduli E' can be increased more easily than when these conditions are not met. For example, in step (II) of the manufacturing method, the temperature of the casting drum with which the molten extrudate of the resin composition comes into contact can be adjusted to a higher temperature within a temperature range at which a film can be formed. For example, in the step (I) of the production method, when a melt of the resin composition containing the thermoplastic polyolefin is extruded through a T-die to form a film, the storage modulus E' can be easily increased by adjusting the draft ratio [Tt / Ft], which is the ratio of the gap thickness (Tt) of the lip of the T-die to the thickness (Ft) of the resulting thermoplastic polyolefin film, to a larger value within a film-formable range. Details of the components of the resin composition and the conditions of the production method will be described later.

[0015] Furthermore, for example, plastic films are also used as optical films such as screen protection films for smartphones and window adhesive films. Therefore, from the perspective of expected expansion into such applications, films formed from thermoplastic polyolefins may also be required to have good optical properties. Therefore, it is preferable that the TPO-based film also has good optical properties. To enable the TPO-based film to have good optical properties, it is also preferable that the TPO-based film have a surface roughness Ra of 1,000 nm or less and an internal haze of 12.0% or less.

[0016] Furthermore, for example, plastic films may be cut into sheets from a film roll and handled in a laminated state, and the laminated films may be supplied to a printing machine and used as a printing film. Therefore, from the perspective of expected expansion into such applications, films formed from resin compositions containing thermoplastic polyolefins as a main component may also be required to have good handling properties. Therefore, it is preferable that the TPO-based film also has good handling properties. From the perspective of making it easier for the TPO-based film to obtain good optical properties and to have good handling properties, it is also preferable that the TPO-based film have a surface roughness Ra within the preferred range described below.

[0017] From the viewpoint of facilitating the TPO-based film to have better optical properties and to ensure ease of handling when the film is spun, the surface roughness Ra is more preferably 700 nm or less, even more preferably 200 nm or less, even more preferably 120 nm or less, and even more preferably 100 nm or less. Furthermore, from the viewpoint of facilitating the production of a film that is easy to handle when spun, as well as to ensure good optical properties, the surface roughness Ra is preferably 30 nm or more, more preferably 40 nm or more, and even more preferably 50 nm or more. As mentioned above, these stepwise lower and upper limits can be independently combined. In one embodiment of the TPO-based film, the surface roughness Ra may be, for example, 30 to 1,000 nm, 40 to 1,000 nm, 50 to 1,000 nm, 30 to 700 nm, 40 to 700 nm, 50 to 700 nm, 30 to 200 nm, 40 to 200 nm, 50 to 200 nm, 30 to 120 nm, 40 to 120 nm, 50 to 120 nm, 30 to 100 nm, 40 to 100 nm, or 50 to 100 nm.

[0018] Furthermore, from the viewpoint of improving the light transmittance of the TPO film and making it easier to obtain better optical properties, the internal haze is more preferably 8.0% or less, even more preferably 6.0% or less, even more preferably 4.0% or less, and even more preferably 2.0% or less. Furthermore, the internal haze may be, for example, 0.0% or more, 0.8% or more, or 1.0% or more. As mentioned above, these stepwise lower and upper limits can be independently combined. For example, in one embodiment of the TPO-based film, the internal haze may be 0.0 to 12.0%, 0.8 to 12.0%, 1.0 to 12.0%, 0.0 to 8.0%, 0.8 to 8.0%, 1.0 to 8.0%, 0.0 to 6.0%, 0.8 to 6.0%, 1.0 to 6.0%, 0.0 to 4.0%, 0.8 to 4.0%, 1.0 to 4.0%, 0.0 to 2.0%, 0.8 to 2.0%, or 1.0 to 2.0%.

[0019] The TPO film preferably has a yellowness index (YI) of 3.50 or less, more preferably 2.50 or less, even more preferably 1.50 or less, even more preferably 1.00 or less, and even more preferably 0.50 or less. The lower limit of the yellowness index (YI) is not particularly limited, but is preferably 0.00, for example. In other words, in one embodiment of the TPO film, the yellowness index (YI) is preferably 0.00 to 3.50, more preferably 0.00 to 2.50, even more preferably 0.00 to 1.50, even more preferably 0.00 to 1.00, and even more preferably 0.00 to 0.50. As described above, the yellowness index (YI) of the TPO film can be specifically measured by the method described in the Examples section below.

[0020] Furthermore, the TPO film preferably has a curl degree, which evaluates flatness from the viewpoint of handleability, of 26 mm or less, more preferably 22 mm or less, even more preferably 18 mm or less, even more preferably 14 mm or less, even more preferably 10 mm or less, even more preferably 6 mm or less, and even more preferably 2 mm or less. The lower limit of the curl degree is not particularly limited, but is preferably, for example, 0 mm. In other words, in one embodiment of the TPO film, the curl degree is preferably 0 to 26 mm, more preferably 0 to 22 mm, even more preferably 0 to 18 mm, even more preferably 0 to 14 mm, even more preferably 0 to 10 mm, even more preferably 0 to 6 mm, and even more preferably 0 to 2 mm. As described above, the curl degree value, which evaluates the flatness of the TPO film, can be specifically measured by the method described in the Examples below.

[0021] The thickness of the TPO film is not particularly limited as long as the effects of the present invention are achieved, and can be appropriately set depending on the application of the film. In one aspect of the present invention, the thickness of the TPO film is preferably 1 to 1,000 μm, more preferably 5 to 500 μm, and even more preferably 10 to 100 μm, from the viewpoints of, for example, film formability and handling properties in post-processing of the film. Specifically, the thickness of the TPO film can be measured by the method described in the examples below.

[0022] <Resin Composition Containing Thermoplastic Polyolefin> The TPO film is formed from a resin composition containing a thermoplastic polyolefin as a main component. That is, the resin composition contains a thermoplastic polyolefin as a main component.

[0023] (Thermoplastic Polyolefin) The thermoplastic polyolefin may be a thermoplastic polyolefin that provides the resulting TPO film with a storage modulus E' of 50 MPa or more at 150°C and a storage modulus E' of 1 MPa or more at 270°C. In one aspect of the present invention, the thermoplastic polyolefin is preferably a thermoplastic polyolefin that provides the TPO film with a surface roughness Ra of 1,000 nm or less and an internal haze of 12.0% or less in addition to the storage moduli at 150°C and 270°C, from the viewpoint of obtaining good optical properties and handleability in addition to heat resistance and thermoformability. The thermoplastic polyolefin is preferably an aliphatic polyolefin, and more preferably a 3-methyl-1-butene polymer, from the viewpoint of more easily obtaining a TPO film with good heat resistance and thermoformability.

[0024] [3-Methyl-1-butene Polymer] The 3-methyl-1-butene polymer (hereinafter also abbreviated as "P3MB") may be a 3-methyl-1-butene homopolymer or a copolymer of 3-methyl-1-butene and an unsaturated hydrocarbon other than 3-methyl-1-butene. Examples of the unsaturated hydrocarbon include ethylene or an α-olefin other than 3-methyl-1-butene. From the viewpoint of good copolymerizability, an α-olefin having 3 to 20 carbon atoms other than 3-methyl-1-butene is preferred. From the viewpoint of optimally exhibiting the physical properties of 3-methyl-1-butene, the 3-methyl-1-butene polymer is preferably at least one selected from the group consisting of a 3-methyl-1-butene homopolymer and a copolymer of 3-methyl-1-butene with at least one α-olefin selected from the group consisting of ethylene and an α-olefin having 3 to 20 carbon atoms other than 3-methyl-1-butene. Hereinafter, in this specification, unless otherwise specified, the term "α-olefin" refers to an α-olefin other than 3-methyl-1-butene.

[0025] When the P3MB is a copolymer of 3-methyl-1-butene and at least one selected from the group consisting of ethylene and an α-olefin, from the viewpoint of more easily obtaining a TPO film having good optical properties, handleability, heat resistance, and thermoformability, the content of structural units derived from at least one selected from the group consisting of ethylene and an α-olefin in the copolymer is preferably more than 0 mol% and 20 mol% or less, based on 100 mol% of the total amount of structural units derived from monomers. Furthermore, from the viewpoint of favorably exhibiting the physical properties of the at least one selected from the group consisting of ethylene and an α-olefin, the content of structural units derived from at least one selected from the group consisting of ethylene and an α-olefin in the copolymer is more preferably 0.1 mol% or more, even more preferably 0.3 mol% or more, and still more preferably 0.5 mol% or more, based on 100 mol% of the total amount of structural units derived from monomers. Furthermore, from the viewpoint of easily maintaining the physical properties of 3-methyl-1-butene and more easily obtaining a TPO-based film having good optical properties, handleability, heat resistance, and thermoformability, the content of structural units derived from at least one selected from the group consisting of ethylene and an α-olefin in the copolymer is more preferably 15 mol% or less, even more preferably 10 mol% or less, and even more preferably 5 mol% or less, based on 100 mol% of the total amount of structural units derived from the monomers. As described above, these stepwise lower and upper limits can be independently combined. For example, from the viewpoint of more easily obtaining a TPO-based film having good optical properties, handleability, heat resistance, and thermoformability, in one embodiment of the copolymer, the content of structural units derived from at least one selected from the group consisting of ethylene and an α-olefin in the copolymer is more preferably 0.1 to 15 mol%, even more preferably 0.3 to 10 mol%, and even more preferably 0.5 to 5 mol%, based on 100 mol% of the total amount of structural units derived from the monomers.Here, in this specification, the "total amount of structural units derived from monomers" means, for example, structural units contained due to impurities in the polymerization solvent and monomers when polymerizing a polymer, as well as components necessary for polymer polymerization such as catalysts, polymerization initiators, chain transfer agents, and coupling agents, but does not include structural units derived from components other than the monomers. Here, the content of structural units derived from at least one selected from the group consisting of ethylene and α-olefins in the copolymer can be determined using a Fourier transform infrared spectrophotometer (FT-IR). Specifically, it can be measured by the method described in the Examples below.

[0026] When the P3MB is a copolymer of 3-methyl-1-butene and at least one selected from the group consisting of ethylene and an α-olefin, the content of structural units derived from 3-methyl-1-butene in the copolymer is preferably 80 mol% or more but less than 100 mol%, based on 100 mol% of all structural units derived from the monomers, from the viewpoint of more easily obtaining a TPO film having good optical properties, handleability, heat resistance, and thermoformability. Furthermore, the content of structural units derived from 3-methyl-1-butene in the copolymer is more preferably 85 mol% or more, even more preferably 90 mol% or more, and even more preferably 95 mol% or more, based on 100 mol% of all structural units derived from the monomers, from the viewpoint of more easily maintaining the physical properties of 3-methyl-1-butene and more easily obtaining a TPO film having good optical properties, handleability, heat resistance, and thermoformability. Furthermore, from the viewpoint of favorably exhibiting the properties of at least one selected from the group consisting of ethylene and α-olefins, the content of structural units derived from 3-methyl-1-butene in the copolymer is more preferably 99.9 mol% or less, even more preferably 99.7 mol% or less, and even more preferably 99.5 mol% or less, based on 100 mol% of the total amount of structural units derived from the monomers. As described above, these stepwise lower and upper limits can be independently combined. For example, from the viewpoint of more easily obtaining a TPO film having good optical properties, handleability, heat resistance, and thermoformability, in one embodiment of the copolymer, the content of structural units derived from 3-methyl-1-butene in the copolymer is more preferably 85 to 99.9 mol%, even more preferably 90 to 99.7 mol%, and even more preferably 95 to 99.5 mol%, based on 100 mol% of the total amount of structural units derived from the monomers.

[0027] From the viewpoint of suitably exhibiting the physical properties of 3-methyl-1-butene, the α-olefin having 3 to 20 carbon atoms is preferably an α-olefin having 4 to 16 carbon atoms, more preferably an α-olefin having 4 to 12 carbon atoms, and even more preferably an α-olefin having 4 to 10 carbon atoms. The α-olefin having 3 to 20 carbon atoms may be linear or branched. Examples of the α-olefins having 3 to 20 carbon atoms include propylene, 1-butene, 1-pentene, 1-hexene, 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-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene, etc. One type of the α-olefins having 3 to 20 carbon atoms may be used alone, or two or more types may be used in combination.

[0028] From the viewpoint of the balance between the processability of the resin composition and the heat resistance and thermoformability of the resulting TPO film, the melting point of the P3MB is preferably 260 to 310° C., more preferably 265 to 305° C., even more preferably 270 to 300° C., still more preferably 275 to 295° C., and even more preferably 280 to 290° C. Specifically, the melting point can be measured by the method described in the examples below.

[0029] From the viewpoint of the balance between the fluidity of the resin composition during molding and the mechanical strength of the resulting TPO film, the melt viscosity of the P3MB is preferably 10 to 9,500 Pa s, more preferably 50 to 5,000 Pa s, even more preferably 100 to 2,000 Pa s, and still more preferably 200 to 1,000 Pa s. Specifically, the melt viscosity can be measured by the method described in the examples below.

[0030] The method for producing P3MB is not particularly limited, and it can be produced using well-known catalysts such as Ziegler-Natta catalysts and metallocene catalysts. For example, as described in JP-A-61-103910, P3MB can be obtained as a powder by homopolymerizing 3-methyl-1-butene or copolymerizing 3-methyl-1-butene with the above-mentioned α-olefins in the presence of a catalyst. The stereoregularity of P3MB may be isotactic or syndiotactic. The copolymer may be a random copolymer, a block copolymer, or an alternating copolymer.

[0031] Furthermore, from the viewpoint of more easily obtaining a TPO-based film having good optical properties, handleability, heat resistance, and thermoformability, the content of the thermoplastic polyolefin in the resin composition is preferably 50.0% by mass or more, more preferably 60.0% by mass or more, even more preferably 65.0% by mass or more, even more preferably 75.0% by mass or more, even more preferably 85.0% by mass or more, even more preferably 90.0% by mass or more, even more preferably 95.0% by mass or more, and even more preferably 96.0% by mass or more, based on the total amount (100% by mass) of the resin composition. Furthermore, the content of the thermoplastic polyolefin in the resin composition is 100% by mass or less, preferably 99.9% by mass or less, more preferably 99.8% by mass or less, and even more preferably 99.7% by mass or less, based on the total amount (100% by mass) of the resin composition. As mentioned above, these lower and upper limits described in stages can be independently combined. For example, from the viewpoint of making it easier to obtain a TPO-based film having good optical properties, handleability, heat resistance and thermoformability, in one aspect of the present invention, the content of the thermoplastic polyolefin in the resin composition is, based on 100% by mass of the total amount of the resin composition, preferably 50.0 to 100% by mass, more preferably 50.0 to 99.9% by mass, even more preferably 60.0 to 99.9% by mass, still more preferably 65.0 to 99.9% by mass, still more preferably 75.0 to 99.9% by mass, still more preferably 85.0 to 99.9% by mass, still more preferably 90.0 to 99.9% by mass, still more preferably 95.0 to 99.9% by mass, still more preferably 95.0 to 99.8% by mass, still more preferably 95.0 to 99.7% by mass, still more preferably 96.0 to 99.7% by mass.

[0032] In one embodiment of the TPO film, the P3MB content in the resin composition is preferably 50.0% by mass or more, more preferably 60.0% by mass or more, even more preferably 65.0% by mass or more, even more preferably 75.0% by mass or more, even more preferably 85.0% by mass or more, even more preferably 90.0% by mass or more, even more preferably 95.0% by mass or more, and even more preferably 96.0% by mass or more, based on the total amount (100% by mass) of the resin composition, from the viewpoint of more easily obtaining a TPO film having good optical properties, handleability, heat resistance, and thermoformability. Furthermore, the P3MB content in the resin composition is 100% by mass or less, preferably 99.9% by mass or less, more preferably 99.8% by mass or less, and even more preferably 99.7% by mass or less, based on the total amount (100% by mass) of the resin composition. As described above, these stepwise lower and upper limits can be independently combined. For example, from the viewpoint of making it easier to obtain a TPO-based film having good optical properties, handleability, heat resistance, and thermoformability, in one aspect of the present invention, the content of P3MB in the resin composition is, based on 100% by mass of the total amount of the resin composition, preferably 50.0 to 100% by mass, more preferably 50.0 to 99.9% by mass, even more preferably 60.0 to 99.9% by mass, still more preferably 65.0 to 99.9% by mass, still more preferably 75.0 to 99.9% by mass, still more preferably 85.0 to 99.9% by mass, still more preferably 90.0 to 99.9% by mass, still more preferably 95.0 to 99.9% by mass, still more preferably 95.0 to 99.8% by mass, still more preferably 95.0 to 99.7% by mass, still more preferably 96.0 to 99.7% by mass.

[0033] From the viewpoint of making it easier to obtain a TPO-based film having good optical properties, handleability, heat resistance, and thermoformability, the content of P3MB in the resin composition is preferably 50.0% by mass or more, more preferably 60.0% by mass or more, even more preferably 65.0% by mass or more, still more preferably 75.0% by mass or more, still more preferably 85.0% by mass or more, still more preferably 90.0% by mass or more, still more preferably 95.0% by mass or more, and still more preferably 96.0% by mass or more, based on 100% by mass of the total amount of polymers in the resin composition. The content of P3MB in the resin composition is 100% by mass or less. In other words, in one embodiment of the present invention, the content of P3MB in the resin composition is preferably 50.0 to 100% by mass, more preferably 60.0 to 100% by mass, even more preferably 65.0 to 100% by mass, still more preferably 75.0 to 100% by mass, even more preferably 85.0 to 100% by mass, still more preferably 90.0 to 100% by mass, still more preferably 95.0 to 100% by mass, still more preferably 95.0 to 100% by mass, still more preferably 95.0 to 100% by mass, still more preferably 95.0 to 100% by mass, and still more preferably 96.0 to 100% by mass. Furthermore, the content of P3MB in the resin composition may be 100% by mass, based on 100% by mass of the total amount of polymers in the resin composition.

[0034] (Alkyl Radical Scavenger) The resin composition preferably contains an alkyl radical scavenger. The inclusion of an alkyl radical scavenger in the resin composition facilitates the production of a TPO-based film with excellent optical properties, handleability, heat resistance, and thermoformability, and is also preferred from the viewpoint of further improving the flatness and yellowness index (YI) of the TPO-based film. In this specification, "alkyl radical scavenger" refers to a compound that reacts with the alkyl radical derived from the P3MB and stabilizes the alkyl radical. By stabilizing the alkyl radical, the function of suppressing a chain reaction of carbon-carbon bond dissociation reactions initiated by the alkyl radical is exhibited. The resin composition preferably contains, as the alkyl radical scavenger, at least one selected from the group consisting of an acrylic phenol compound and a benzofuranone compound. One alkyl radical scavenger may be used alone, or two or more may be used in combination.

[0035] [Acrylphenol Compound] As the acrylic phenol compound, for example, a compound represented by the following general formula (I) can be used.

[0036]

[0037] In general formula (I), R １ represents a hydrogen atom or a methyl group, and R ２ represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and R ３ , R ４ , R ５ and R ６each independently represents an alkyl group having 1 to 9 carbon atoms. Examples of the alkyl group having 1 to 3 carbon atoms include a methyl group, an ethyl group, an n-propyl group, and an isopropyl group. The alkyl group having 1 to 9 carbon atoms may be linear or branched. Examples of the alkyl group having 1 to 9 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an s-butyl group, a t-butyl group, a 1,1-dimethylpropyl group, a 1,2-dimethylpropyl group, a 2,2-dimethylpropyl group, a 1-methylbutyl group, a 2-methylbutyl group, a 3-methylbutyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, and an n-nonyl group. R １ is preferably a hydrogen atom. ２ is preferably a hydrogen atom or a methyl group, more preferably a methyl group. ３ , R ４ , R ５ and R ６ are each independently preferably an alkyl group having 3 to 8 carbon atoms, more preferably an alkyl group having 5 carbon atoms, and even more preferably a 1,1-dimethylpropyl group.

[0038] Examples of the acrylic phenol compound represented by general formula (I) include 2,4-di-t-amyl-6-[1-(3,5-di-t-amyl-2-hydroxyphenyl)ethyl]phenyl acrylate, 2,4-di-t-butyl-6-[1-(3,5-di-t-butyl-2-hydroxyphenyl)ethyl]phenyl acrylate, and 2-t-butyl-6-[(3-t-butyl-2-hydroxy-5-methylphenyl)methyl]-4-methylphenyl acrylate. The alkyl radical scavenger may be a commercially available product, and examples of commercially available acrylic phenol compounds represented by general formula (I) include those manufactured by Sumitomo Chemical Co., Ltd. under the trade names "Sumilizer (registered trademark) GS" and "Sumilizer (registered trademark) GM."

[0039] [Benzofuranone Compound] As the benzofuranone compound, for example, at least one compound selected from the group consisting of a compound represented by the following general formula (II) and 4-t-butyl-2-(5-t-butyl-2-oxo-3H-benzofuran-3-yl)phenyl-3,5-di-t-butyl-4-hydroxybenzoate can be used.

[0040]

[0041] In general formula (II), R ７ and R ８ each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; R ９ and R １０ each independently represents a hydrogen atom or an alkyl group having 1 to 9 carbon atoms. Examples of the alkyl group having 1 to 4 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an s-butyl group, and a t-butyl group. The alkyl group having 1 to 9 carbon atoms may be linear or branched. Examples of the alkyl group having 1 to 9 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an s-butyl group, a t-butyl group, a 1,1-dimethylpropyl group, a 1,2-dimethylpropyl group, a 2,2-dimethylpropyl group, a 1-methylbutyl group, a 2-methylbutyl group, a 3-methylbutyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, and an n-nonyl group. R ７ and R ８ are each independently preferably an alkyl group having 1 to 3 carbon atoms, more preferably a methyl group. ９ and R １０ are each independently preferably an alkyl group having 1 to 4 carbon atoms, more preferably a t-butyl group.

[0042] Examples of the benzofuranone compound represented by general formula (II) include 5,7-di-t-butyl-3-(3,4-di-methyl-phenyl)-3H-benzofuran-2-one and 5,7-di(t-butyl)-3-(3,4-di-propyl-phenyl)-3H-benzofuran-2-one. Commercially available alkyl radical scavengers may be used, and examples of commercially available benzofuranone compounds include "Irganox (registered trademark) HP-136" manufactured by BASF and "Revonox (registered trademark) 501" manufactured by Chitec.

[0043] From the viewpoint of more easily achieving the effects of the present invention, the content of the alkyl radical scavenger in the resin composition is preferably 0.01 to 1.00 parts by mass, more preferably 0.02 to 0.80 parts by mass, and even more preferably 0.05 to 0.70 parts by mass, relative to 100 parts by mass of the thermoplastic polyolefin. When the resin composition contains two or more types of alkyl radical scavengers, the content of the alkyl radical scavengers means the total content of the alkyl radical scavengers.

[0044] (Antioxidant) The resin composition preferably contains an antioxidant. The inclusion of an antioxidant in the resin composition makes it easier to obtain a TPO-based film having good optical properties, handleability, heat resistance, and thermoformability, and is also preferred from the viewpoint of further improving the flatness and yellowness index (YI) of the TPO-based film. The resin composition preferably contains, as the antioxidant, at least one selected from the group consisting of phenolic antioxidants and phosphorus-based antioxidants. One type of antioxidant may be used alone, or two or more types may be used in combination. In this specification, the antioxidant that also acts as an alkyl radical scavenger is considered to be an alkyl radical scavenger.

[0045] [Phenol-Based Antioxidants] Examples of the phenol-based antioxidants include pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], 1,3,5-tris(3,5-di-t-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, and 1,3,5-tris[(4-t-butyl-3-hydroxy-2,6-xylyl)methyl]-1,3,5-triazine-2,4,6(1H,3H,5H)-trione. , octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, thiodiethylene-bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], N,N'-hexane-1,6-diylbis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionamide], 3,3',3'',5,5',5''-hexa-t-butyl-α,α',α''-(mesitylene-2,4,6-triyl)tri-p-cresol, ethylene Bis(oxyethylene)bis[3-(5-t-butyl-4-hydroxy-m-tolyl)propionate], hexamethylene-bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], 2,6-di-t-butyl-4-[4,6-bis(octylthio)-1,3,5-triazin-2-ylamino]phenol, 3,9-bis[2-(3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy)-1,1-dimethylethyl]-2 , 4,8,10-tetraoxaspiro(5,5)undecane, 4,4',4''-(1-methylpropanyl-3-ylidene)tris(6-t-butyl-m-cresol), 6,6'-di-t-butyl-4,4'-butylidene-di-m-cresol, octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)-propionate, and benzenepropionic acid 3,5-bis-(1,1-dimethylethyl)-4-hydroxy-C7-C9 branched alkyl ester.

[0046] As the phenolic antioxidant, commercially available products may be used, such as "ADEKA STAB (registered trademark) AO series" manufactured by ADEKA Corporation and "Irganox (registered trademark) series" manufactured by BASF Japan Ltd.

[0047] [Phosphorus-Based Antioxidant] Examples of the phosphorus-based antioxidant include 3,9-bis(2,6-di-t-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane, tetrakis(2,4-di-t-butyl-phenyl)-4,4′-biphenylenephosphonite, 2,2-methylenebis(4,6-di-t-butylphenyl)octylphosphite, tris(2,4-di-t-butylphenyl)phosphite, and the like. phosphate, bis(2,4-bis(1,1-dimethylethyl)-6-methylphenyl)ethyl ester phosphite, bis(2,4-di-t-butylphenyl)pentaerythritol diphosphite, bis(2,4-dicumylphenyl)pentaerythritol diphosphite, di-t-butyl-m-cresyl-phosphonite, diethyl[(3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl)methyl]phosphite sulfonate, tris(2,4-di-t-butylphenyl)phosphite, tetrakis(2,4-di-t-butylphenyl)-4,4'-biphenylene diphosphonite, 3,9-bis(octadecyoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane, tris(2,4-di-t-butylphenyl)phosphite, tris(nonylphenyl)phosphite, tetra-C12-15-al Examples of suitable phosphite compounds include 2-ethylhexyl(propane-2,2-diylbis(4,1-phenylene))bis(phosphite), 2-ethylhexyldiphenyl phosphite, isodecyldiphenyl phosphite, trisisodecyl phosphite, triphenyl phosphite, and 3,9-bis[2,4-bis(1-methyl-1-phenylethyl)phenoxy]-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane.

[0048] As the phosphorus-based antioxidant, commercially available products may be used, and examples thereof include "ADK STAB (registered trademark) PEP series" and "ADK STAB (registered trademark) HP series" manufactured by ADEKA Corporation, "Irgafos (registered trademark) series" manufactured by BASF Japan Ltd., and "HOSTANOX (registered trademark) P-EPQ" manufactured by Clariant.

[0049] [Other Antioxidants] The resin composition may contain an antioxidant other than the phenolic antioxidant and the phosphorus-based antioxidant as long as the effects of the present invention are achieved. Examples of the antioxidant other than the phenolic antioxidant and the phosphorus-based antioxidant include sulfur-based antioxidants and amine-based antioxidants.

[0050] From the viewpoint of more easily achieving the effects of the present invention, the content of the antioxidant in the resin composition is preferably 0.01 parts by mass or more, more preferably 0.10 parts by mass or more, per 100 parts by mass of the thermoplastic polyolefin. Furthermore, from the viewpoint of suppressing bleed-out and sublimation of the antioxidant from the film and from the viewpoint of economy, the content of the antioxidant in the resin composition is preferably 1.00 parts by mass or less, more preferably 0.80 parts by mass or less, per 100 parts by mass of the thermoplastic polyolefin. As described above, these stepwise lower and upper limits can be independently combined. For example, in one embodiment of the TPO-based film, the content of the antioxidant in the resin composition is preferably 0.01 to 1.00 parts by mass, more preferably 0.10 to 0.80 parts by mass, per 100 parts by mass of the thermoplastic polyolefin. When the resin composition contains two or more antioxidants, the content of the antioxidants refers to the total content of the antioxidants.

[0051] (Other Additives) The resin composition may contain additives other than the alkyl radical scavenger and the antioxidant, as long as the effects of the present invention are not impaired. Examples of other additives include antacids, fillers, light stabilizers, antistatic agents, flame retardants, pigments, polymerization inhibitors, heavy metal deactivators, UV absorbers, nucleating agents, clarifying agents, lubricants, fluorescent brighteners, rust inhibitors, and sliding agents. One type of other additive may be used alone, or two or more types may be used in combination.

[0052] [Antacid Agent] The resin composition preferably contains an antacid from the viewpoint of suppressing deterioration due to acid components generated from residual metals and the like during melt-kneading. Examples of the antacid agent include barium laurate, calcium stearate, zinc stearate, magnesium stearate, aluminum stearate, zinc oleate, and magnesium 12-hydroxystearate. One type of antacid agent may be used alone, or two or more types may be used in combination. When the resin composition contains an antacid agent, the content of the antacid agent in the resin composition can be determined appropriately. For example, the content may be 0.01 to 200 parts by mass, 0.01 to 100 parts by mass, 0.01 to 50 parts by mass, 0.01 to 10 parts by mass, 0.01 to 1.00 parts by mass, or 0.1 to 0.80 parts by mass, relative to 100 parts by mass of the thermoplastic polyolefin.

[0053] [Filler] Examples of the filler include fibrous compounds such as glass fiber, alumina fiber, resin fiber, carbon fiber, and cellulose fiber; flat compounds such as mica, talc, montmorillonite, and tabular aluminum; spherical compounds such as glass beads, shirasu balloons, and acrylic balloons; acicular compounds such as acicular metal titanate, wollastonite, acicular silica, and tin oxide; and powdered compounds such as powdered metal titanate, finely powdered wood chips, titanium oxide, calcium carbonate, silica, and alumina. These fillers may be surface-treated with, for example, a silane coupling agent. A compatibilizer may also be used to enhance the dispersibility of the filler. One type of filler may be used alone, or two or more types may be used in combination. When the resin composition contains a filler, the content of the filler in the resin composition can be determined appropriately. For example, it may be 0.01 to 300 parts by mass or 0.1 to 100 parts by mass per 100 parts by mass of the thermoplastic polyolefin.

[0054] In one embodiment of the present invention, the total content of the thermoplastic polyolefin, the alkyl radical scavenger, and the antioxidant in the resin composition is preferably 50.0% by mass or more, more preferably 60.0% by mass or more, even more preferably 70.0% by mass or more, even more preferably 80.0% by mass or more, even more preferably 90.0% by mass or more, and even more preferably 95.0% by mass or more, based on the total amount (100% by mass) of the resin composition, from the viewpoint of more easily obtaining a TPO-based film having good optical properties, handleability, heat resistance, and thermoformability. Furthermore, the total content of the thermoplastic polyolefin, the alkyl radical scavenger, and the antioxidant in the resin composition is 100% by mass or less, preferably 99.9% by mass or less, based on the total amount (100% by mass) of the resin composition. As mentioned above, these lower and upper limits described in stages can be independently combined. For example, from the viewpoint of making it easier to obtain a TPO-based film having good optical properties, handleability, heat resistance, and thermoformability, in one embodiment of the present invention, the total content of the thermoplastic polyolefin, the alkyl radical scavenger, and the antioxidant is preferably 50.0 to 100% by mass, more preferably 50.0 to 99.9% by mass, even more preferably 60.0 to 99.9% by mass, still more preferably 70.0 to 99.9% by mass, still more preferably 80.0 to 99.9% by mass, still more preferably 90.0 to 99.9% by mass, and still more preferably 95.0 to 99.9% by mass, based on 100% by mass of the total amount of the resin composition.

[0055] In one embodiment of the present invention, the total content of the thermoplastic polyolefin, the alkyl radical scavenger, the antioxidant, and the other additives in the resin composition is preferably 50.0% by mass or more, more preferably 60.0% by mass or more, even more preferably 70.0% by mass or more, still more preferably 80.0% by mass or more, still more preferably 90.0% by mass or more, and even more preferably 95.0% by mass or more, based on 100% by mass of the total amount of the resin composition, from the viewpoint of more easily obtaining a TPO-based film having good optical properties, handleability, heat resistance, and thermoformability. Furthermore, the total content of the thermoplastic polyolefin, the alkyl radical scavenger, the antioxidant, and the other additives in the resin composition is 100% by mass or less, based on 100% by mass of the total amount of the resin composition. In other words, in one embodiment of the present invention, the total content of the thermoplastic polyolefin, the alkyl radical scavenger, the antioxidant, and the other additives in the resin composition is preferably 50.0 to 100 mass%, more preferably 60.0 to 100 mass%, even more preferably 70.0 to 100 mass%, still more preferably 80.0 to 100 mass%, even more preferably 90.0 to 100 mass%, and still more preferably 95.0 to 100 mass%. Also, in one embodiment of the present invention, the total content of the thermoplastic polyolefin, the alkyl radical scavenger, the antioxidant, and the other additives in the resin composition may be 100 mass% in the total amount of the resin composition (100 mass%).

[0056] In one embodiment of the present invention, the resin composition preferably contains substantially no thermosetting resin. Specifically, "substantially no" here means that, based on 100% by mass of the resin composition, the thermosetting resin is present in an amount of 5.0% by mass or less, preferably 1.0% by mass or less, more preferably 0.1% by mass or less, even more preferably 0.05% by mass or less, and even more preferably 0.01% by mass or less. The resin composition may contain 0% by mass of the thermosetting resin based on 100% by mass of the resin composition. In other words, in one embodiment of the present invention, the content of the thermosetting resin in the resin composition is 0 to 5.0% by mass, preferably 0 to 1.0% by mass, more preferably 0 to 0.1% by mass, even more preferably 0 to 0.05% by mass, even more preferably 0 to 0.01% by mass, and may even be 0% by mass. That is, the TPO film preferably contains substantially no thermosetting resin.

[0057] In one embodiment of the present invention, the resin composition preferably contains substantially no cyclic polyolefin as the thermoplastic polyolefin. Here, "substantially no cyclic polyolefin" specifically means that, based on 100% by mass of the resin composition, the cyclic polyolefin content is 5.0% by mass or less, preferably 1.0% by mass or less, more preferably 0.1% by mass or less, even more preferably 0.05% by mass or less, and even more preferably 0.01% by mass or less. The resin composition may contain 0% by mass of cyclic polyolefin based on 100% by mass of the resin composition. In other words, in one embodiment of the present invention, the cyclic polyolefin content in the resin composition is 0 to 5.0% by mass, preferably 0 to 1.0% by mass, more preferably 0 to 0.1% by mass, even more preferably 0 to 0.05% by mass, even more preferably 0 to 0.01% by mass, and may even be 0% by mass. That is, the TPO film preferably contains substantially no cyclic polyolefin. The term "cyclic polyolefin" refers to a polymer having an alicyclic structure (cycloolefin skeleton) in its main chain, and containing structural units derived from a monomer capable of introducing the alicyclic structure into the main chain of the polymer in an amount of at least 10 mol % of the total 100 mol % of the structural units constituting the polymer. The monomer capable of introducing the alicyclic structure into the main chain of the polymer is not particularly limited, and examples thereof include substituted or unsubstituted norbornene, substituted or unsubstituted tetracyclododecene, and substituted or unsubstituted dicyclopentadiene. An example of the cyclic polyolefin is a polymer obtained by subjecting a cyclic olefin monomer such as substituted or unsubstituted norbornene to ring-opening metathesis polymerization (ROMP) to obtain a ring-opening polymer, followed by hydrogenation of the double bonds in the polymer. Another example is a copolymer obtained by addition polymerization of the cyclic olefin monomer with an olefin such as ethylene.Examples of commercially available cyclic polyolefins include "ZEONEX (registered trademark)" and "ZEONOR (registered trademark)" manufactured by Zeon Corporation; "APEL (registered trademark)" manufactured by Mitsui Chemicals, Inc.; "ARTON (registered trademark)" manufactured by JSR Corporation; and "TOPAS (registered trademark)" manufactured by Topas Advanced Polymers GmbH.

[0058] (Method for Producing Resin Composition) The resin composition can be produced by blending and kneading other components, such as the additives described above, in addition to the thermoplastic polyolefin. The blending method for the components is not particularly limited as long as the effects of the present invention are achieved, and for example, a method of melt-kneading using a twin-screw kneading extruder can be used. Note that, for example, when only a 3-methyl-1-butene polymer is used as the thermoplastic polyolefin without blending other polymers and other components, such as the additives described above, the resin composition consists of the 3-methyl-1-butene polymer, and therefore there is no need to undergo a step of obtaining a resin composition by melt-kneading or the like. The conditions for obtaining the resin composition by melt-kneading are described below.

[0059] [Melt-Kneading Conditions] The melt-kneading conditions for obtaining the resin composition by melt-kneading are not particularly limited as long as the effects of the present invention are achieved. However, it is preferable to melt-knead the resin composition by injecting an inert gas into the melt-kneader or by degassing the melt-kneader under reduced pressure. Melt-kneading under an inert atmosphere or low-oxygen conditions can suppress deterioration of the physical properties of the resin composition due to oxygen, making it easier to obtain a TPO film with good optical properties, handleability, heat resistance, and thermoformability. It is also preferable from the viewpoint of improving the flatness and yellowness index (YI) of the TPO film. Here, the "low-oxygen condition" refers to a state in which the oxygen concentration inside the melt-kneader is reduced by degassing the melt-kneader under reduced pressure compared to before degassing. Furthermore, in the "inert atmosphere" condition, the oxygen concentration inside the melt-kneader is reduced by injecting an inert gas into the melt-kneader compared to before the inert gas was injected. Therefore, the concept of "low-oxygen condition" may also include a state in which the oxygen concentration inside the melt-kneader is reduced. In the "low-oxygen state," the oxygen concentration inside the melt-kneader is preferably 5% or less, more preferably 2% or less, and even more preferably 1% or less. The oxygen concentration can be measured using an oxygen concentration meter such as a diaphragm-type galvanic cell type. Examples of the oxygen concentration meter that can be used include the "XP-3180E" (diaphragm-type galvanic cell type) manufactured by New Cosmos Electric Co., Ltd., and its successor, the "XP-3380II-E" (galvanic cell type).

[0060] The method of melt-kneading by injecting an inert gas into the melt-kneader may, for example, be to introduce each component into the melt-kneader while injecting an inert gas into the melt-kneader and perform melt-kneading; after introducing each component into the melt-kneader, preferably before starting to heat or before starting shearing, more preferably before starting to heat and before starting shearing, and then perform melt-kneading; or, after injecting an inert gas into the melt-kneader, to introduce each component from a sealed supply section and perform melt-kneading. Also, during melt-kneading, the inert gas may be continuously injected into the melt-kneader. The method of injecting the inert gas can be carried out depending on the equipment provided in each melt-kneader, and it is preferable to inject the inert gas into the entire area from the inert gas supply section to the heating section where melt-kneading is performed, and there are no particular restrictions on the injection method. For example, the inert gas may be introduced from a supply section for a gas such as an inert gas provided in the melt kneader, from a supply section for each component provided in the melt kneader, or from a gas vent provided in the melt kneader. Examples of the inert gas include nitrogen gas, helium gas, neon gas, argon gas, krypton gas, and carbon dioxide gas, and nitrogen gas is preferred from the viewpoints of availability and versatility.

[0061] The method of melt-kneading while degassing the inside of the melt-kneader under reduced pressure may involve, for example, introducing each component into the melt-kneader while degassing the inside of the melt-kneader, and then melt-kneading. Alternatively, after introducing each component into the melt-kneader, degassing the inside of the melt-kneader under reduced pressure, preferably before starting the temperature increase or before starting shearing, more preferably before starting the temperature increase and before starting shearing, and then melt-kneading. Alternatively, after degassing the inside of the melt-kneader under reduced pressure, each component may be introduced from a sealed supply port and then melt-kneaded. Furthermore, degassing the inside of the melt-kneader under reduced pressure may be performed intermittently or continuously during melt-kneading. The method of degassing the inside of the melt-kneader under reduced pressure may be performed depending on the equipment provided in each melt-kneader, and may be performed, for example, through a vacuum vent. For example, a vacuum pump may be used for degassing the inside of the melt-kneader. There are no limitations on the method of degassing the inside of the melt-kneader under reduced pressure, as long as it is possible to perform melt-kneading under an inert atmosphere or in a low-oxygen environment. When degassing under reduced pressure, the inside of the melt kneader can be made into a vacuum state of, for example, 0.1 to 50 kPa.

[0062] The melt kneader may be a single-screw extruder, a multi-screw extruder, a kneader, a Banbury mixer, or the like, which is equipped with equipment capable of melt-kneading by injecting an inert gas into the interior of the melt kneader, or equipment capable of melt-kneading by degassing the interior of the melt kneader under reduced pressure.

[0063] The injection of the inert gas and the degassing under reduced pressure may be used in combination. In this case, it is preferable to inject the inert gas upstream of the melt kneader before or together with the raw materials, and on the other hand, to carry out degassing under reduced pressure further downstream. It is also more preferable to inject the inert gas upstream of the melt kneader before or together with the raw materials, and on the other hand, to carry out degassing under reduced pressure further downstream, and to continue both the injection of the inert gas and the degassing under reduced pressure during melt kneading.

[0064] The temperature during melt-kneading is preferably 280 to 323°C. When the temperature during melt-kneading is 280°C or higher, even when a 3-methyl-1-butene polymer suitable for use as the thermoplastic polyolefin is used, the 3-methyl-1-butene polymer can be sufficiently melted, making it easier to disperse the additives described above. When the temperature during melt-kneading is 323°C or lower, thermal decomposition of the thermoplastic polyolefin or the additives described above can be suppressed. From the viewpoint of sufficiently dispersing the additives described above in the thermoplastic polyolefin, the temperature during melt-kneading is more preferably 285°C or higher, even more preferably 290°C or higher, and even more preferably 292°C or higher. Furthermore, from the viewpoint of being able to suppress decomposition of each component and more easily obtain a TPO film having good optical properties, handleability, heat resistance, and thermoformability, as well as from the viewpoint of further improving the flatness and yellowness index (YI) of the TPO film, the temperature during the melt-kneading is more preferably 315° C. or less, even more preferably 305° C. or less, still more preferably 300° C. or less, and even more preferably 298° C. or less. As described above, these stepwise lower limit values ​​and upper limit values ​​can be independently combined. For example, from the viewpoint of sufficiently melt-kneading each component, making it easier to obtain a TPO-based film having good optical properties, handleability, heat resistance, and thermoformability, and making the TPO-based film have even better flatness and yellowness index (YI), in one embodiment of the present invention, the temperature during the melt-kneading is preferably 280 to 323°C, more preferably 285 to 315°C, even more preferably 290 to 305°C, still more preferably 290 to 300°C, and even more preferably 292 to 298°C.

[0065] The TPO film can be produced by an extrusion molding method such as a T-die casting method or an inflation method, preferably a T-die casting method. From the viewpoint of making the TPO film easier to obtain, it is more preferable to produce it by the method for producing a thermoplastic polyolefin film, which is one embodiment of the present invention, as described below.

[0066] [Method for producing thermoplastic polyolefin film] A method for producing a thermoplastic polyolefin film according to one embodiment of the present invention includes a step (I) of melt-extruding a resin composition containing a thermoplastic polyolefin as a main component, to produce a thermoplastic polyolefin film having a storage modulus E' of 50 MPa or more at 150°C and a storage modulus E' of 1 MPa or more at 270°C. The thermoplastic polyolefin film obtained by this production method is similar to that described above in the "Thermoplastic Polyolefin Film" section, and preferred embodiments thereof are also similar. Therefore, the resin composition containing the thermoplastic polyolefin as a main component used in this production method, as well as the thermoplastic polyolefin contained in the resin composition and other components that the resin composition may contain, are also similar to those described above, and preferred embodiments thereof are also similar. Therefore, the thermoplastic polyolefin film according to one embodiment of the present invention is preferably a thermoplastic polyolefin film produced by this production method.

[0067] <Step (I)> Step (I) is a step of melt-extruding a resin composition containing a thermoplastic polyolefin as a main component. As a method for melt-extruding the resin composition, it is preferable to use an extruder, from the viewpoint of easily obtaining a film with excellent manufacturing ease and dimensional accuracy. As the extruder, for example, a single-screw extruder or a multi-screw extruder such as a twin-screw kneading extruder can be used. When the resin composition is at least one of a composition containing multiple polymers and a composition containing the above-mentioned various additives, it is preferable to use a multi-screw extruder such as a twin-screw kneading extruder from the viewpoint of sufficiently melt-kneading each component.

[0068] In step (I), the resin composition is preferably melted in an inert atmosphere or a low-oxygen state, more preferably in an inert atmosphere. Melting the resin composition in an inert atmosphere or a low-oxygen state can suppress deterioration of the physical properties of the resin composition due to oxygen, making it easier to obtain a TPO-based film having good optical properties, handleability, heat resistance, and thermoformability, and is also preferred from the viewpoint of improving the flatness and yellowness index (YI) of the TPO-based film. For example, when an extruder is used in step (I), the resin composition is preferably melted using at least one method selected from the following: injecting an inert gas into the extruder to melt the resin composition; and degassing the inside of a melt-kneader under reduced pressure to melt the resin composition.

[0069] Examples of methods for melting the resin composition by injecting an inert gas into an extruder include a method in which the resin composition prepared in advance by the method described above in the "Method for Producing a Resin Composition" section is introduced into the extruder through a raw material inlet such as a hopper while injecting an inert gas into the extruder, and the resin composition is melted in the extruder; or a method in which the resin composition is introduced into the extruder through a raw material inlet such as a hopper, and then an inert gas is injected into the extruder, preferably before the start of heating or before the start of shearing, more preferably before the start of heating and before the start of shearing, and then the resin composition is melted in the extruder. Furthermore, the inert gas may be continuously injected into the extruder while the resin composition is melting, and it is preferable that the inert gas be continuously injected into the extruder while the resin composition is melting. The method for injecting the inert gas can be performed depending on the equipment of the extruder used. It is preferable that the inert gas be injected into the entire extruder from the inert gas supply section to the heating section where melt-kneading is performed, and the injection method is not particularly limited. For example, the inert gas may be supplied from a gas supply section such as an inert gas provided in the extruder, or from a supply section for each component such as a hopper provided in the extruder. Examples of the inert gas include nitrogen gas, helium gas, neon gas, argon gas, krypton gas, and carbon dioxide gas, and nitrogen gas is preferred from the viewpoints of availability and versatility.

[0070] Examples of methods for melting the resin composition by degassing the inside of an extruder under reduced pressure include a method in which the resin composition prepared in advance by the method described above in the "Method for Producing a Resin Composition" section is introduced into a raw material inlet such as a hopper while degassing the inside of the extruder under reduced pressure and melted therein; or a method in which the resin composition is introduced into the extruder through a raw material inlet such as a hopper, and then the inside of the extruder is degassed under reduced pressure and melted therein, preferably before starting the temperature increase or before starting shearing, more preferably before starting the temperature increase and before starting shearing. Furthermore, while the resin composition is being melted, degassing under reduced pressure inside the extruder may be performed intermittently or continuously. It is preferable to perform degassing under reduced pressure continuously while the resin composition is being melted. There are no limitations on the method for degassing the inside of the extruder under reduced pressure, as long as the resin composition can be melt-kneaded under an inert atmosphere or a low-oxygen state. For example, in one embodiment of the production method, degassing under reduced pressure inside the extruder can be performed depending on the equipment provided in the extruder used, and may be performed, for example, through a vacuum vent. For the degassing under reduced pressure, for example, a decompression pump such as a vacuum pump can be used. Furthermore, by performing degassing under reduced pressure inside the extruder, it is possible to remove moisture remaining in the resin composition and organic solvents that evaporate at the melting temperature, and therefore, when the melt is extruded from a T-die or the like, foaming of the melt due to moisture, etc. can be suppressed, which is preferable. From this viewpoint, the degassing under reduced pressure is preferably performed after the resin composition is melted and before it is extruded, and may be performed, for example, from a vent provided in a barrel corresponding to the position of the shearing section of the extruder.

[0071] The injection of the inert gas and the degassing under reduced pressure may be used in combination. In this case, it is preferable to inject the inert gas upstream of the extruder before or together with the raw materials, and to carry out degassing under reduced pressure further downstream. It is also more preferable to inject the inert gas upstream of the extruder before or together with the raw materials, and to carry out degassing under reduced pressure further downstream, and to continue both the injection of the inert gas and the degassing under reduced pressure during melt-kneading.

[0072] As described above, the resin composition used in the step (I) may be a resin composition prepared in advance by the method described above in the section "Method for producing a resin composition," or a method may be used in which, during the step (I), for example, a twin-screw kneading extruder is used as the extruder, the components described above are kneaded in the extruder to prepare the resin composition, and the molten resin composition is directly extruded from the extruder.

[0073] In step (I), it is preferable to melt the resin composition containing the thermoplastic polyolefin as a main component at 280 to 323°C. In step (I), melting the resin composition at a temperature of 280°C or higher is preferable because, for example, even when a 3-methyl-1-butene polymer, which is suitable as the thermoplastic polyolefin, can be used, the resin composition can be sufficiently melted, facilitating the molding of the TPO film. From this perspective, the temperature at which the resin composition is melted in step (I) is more preferably 285°C or higher, even more preferably 290°C or higher, and even more preferably 292°C or higher. Furthermore, melting the resin composition at a temperature of 323°C or lower can suppress thermal decomposition of the thermoplastic polyolefin or the aforementioned additives. This is also preferable from the viewpoint of facilitating an improvement in the storage modulus E' at each of the aforementioned temperatures. This is also preferred from the viewpoint of making it easier to obtain a TPO film having good optical properties, handleability, heat resistance, and thermoformability, and also from the viewpoint of improving the flatness and yellowness index (YI) of the TPO film. From these viewpoints, the temperature at which the resin composition is melted in step (I) is more preferably 315° C. or less, even more preferably 305° C. or less, still more preferably 300° C. or less, and even more preferably 298° C. or less. As mentioned above, these stepwise lower and upper limits can be independently combined. For example, in view of a balance among the viewpoints of sufficiently melt-kneading each component, facilitating an improvement in the storage modulus E' at each of the aforementioned temperatures, making it easier to obtain a TPO film having good optical properties, handleability, heat resistance, and thermoformability, and further improving the flatness and yellowness index (YI) of the TPO film, in one embodiment of the present invention, the temperature at which the resin composition is melted in step (I) is preferably 280 to 323° C., more preferably 285 to 315° C., even more preferably 290 to 305° C., still more preferably 290 to 300° C., and even more preferably 292 to 298° C. Furthermore, within the range in which a TPO film can be formed, the surface roughness Ra and internal haze tend to be smaller as the temperature at which the resin composition is melted is lower.

[0074] In step (I), the resin composition is melted, then extruded, for example, through a die attached to the tip of an extruder, and then cooled. The die is not particularly limited as long as it can produce the TPO-based film, but a T-die is preferably used from the viewpoint of ease of production and the ease of obtaining a film with excellent dimensional accuracy. The cooling method is also not particularly limited as long as it can produce the TPO-based film, but it is preferable to cool using a casting drum as shown in the following step (II).

[0075] <Step (II)> The production method preferably includes step (II) of contacting a casting drum with a molten extrudate of the resin composition containing the thermoplastic polyolefin as a main component, obtained in step (I). The temperature of the casting drum is not particularly limited as long as the TPO film can be formed, but is preferably 40°C or higher. A casting drum temperature of 40°C or higher is also preferred from the viewpoint of facilitating an improvement in the storage modulus E' at each of the aforementioned temperatures. Furthermore, a casting drum temperature of 40°C or higher is also preferred from the viewpoints of more easily obtaining a TPO film having good optical properties, handleability, heat resistance, and thermoformability, as well as further improving the flatness and yellowness index (YI) of the TPO film. Furthermore, within the range in which a TPO film can be formed, a higher casting drum temperature tends to result in smaller values ​​for the surface roughness Ra and internal haze. From these viewpoints, the temperature of the casting drum is more preferably 50°C or higher, preferably 60°C or higher, even more preferably 80°C or higher, even more preferably 100°C or higher, even more preferably 120°C or higher, even more preferably 140°C or higher, and even more preferably 160°C or higher. Furthermore, from the viewpoint of facilitating film formation, such as preventing the molten extrudate from fusing to the casting drum, the temperature of the casting drum is preferably 250°C or lower, more preferably 240°C or lower, even more preferably 230°C or lower, even more preferably 220°C or lower, even more preferably 210°C or lower, even more preferably 200°C or lower, and even more preferably 190°C or lower. As described above, these lower limit values ​​and upper limit values ​​described in stages can be independently combined.For example, in view of facilitating an improvement in the storage modulus E' at each of the aforementioned temperatures, making it easier to obtain a TPO film having good optical properties, handleability, heat resistance, and thermoformability, making the flatness and yellowness index (YI) of the TPO film even more excellent, and balancing these with the viewpoint of improving film formability, in one embodiment of the present invention, the temperature of the casting drum in step (II) is preferably 40 to 250°C, more preferably 50 to 240°C, even more preferably 60 to 230°C, still more preferably 80 to 220°C, still more preferably 100 to 210°C, still more preferably 120 to 210°C, still more preferably 140 to 200°C, and still more preferably 160 to 190°C. Here, the "temperature of the casting drum" refers to the temperature of the surface of the casting drum.

[0076] The melt extrudate from step (I) is preferably cooled and solidified in step (II) to form the TPO film. Thereafter, the extrudate may be wound into a roll using a winder or the like, if necessary. Furthermore, the extrudate may be further stretched using a stretching machine or the like, if necessary.

[0077] In one embodiment of the production method, in step (I), a melt of the resin composition containing the thermoplastic polyolefin as a main component is preferably extruded through a T-die, and a film is formed so that the draft ratio [Tt / Ft], which is the ratio of the gap thickness (Tt) at the lip of the T-die to the thickness (Ft) of the resulting thermoplastic polyolefin film, is 1 to 30. A draft ratio [Tt / Ft] of 1 or more is also preferred from the viewpoint of facilitating an improvement in the storage modulus E' at each of the temperatures described above. Furthermore, a draft ratio [Tt / Ft] of 1 or more is also preferred from the viewpoint of facilitating the production of a TPO film having good optical properties, handleability, heat resistance, and thermoformability, as well as facilitating the production of a TPO film with even better flatness and yellowness index (YI). Furthermore, within the range in which a TPO film can be formed, the higher the draft ratio [Tt / Ft], the smaller the surface roughness Ra and internal haze values ​​tend to be. From these viewpoints, the draft ratio [Tt / Ft] is more preferably 2 or more, even more preferably 4 or more, even more preferably 8 or more, and even more preferably 10 or more. Furthermore, from the viewpoint of improving the yellowness index (YI) among the aforementioned properties, it is more preferably 14 or more. Furthermore, from the viewpoint of preventing film breakage during film formation and post-processing, more easily suppressing film thickness unevenness, and more easily suppressing shrinkage during thermoforming, the draft ratio [Tt / Ft] is more preferably 28 or less, even more preferably 26 or less, even more preferably 24 or less, even more preferably 22 or less, and even more preferably 20 or less. As described above, these stepwise lower and upper limits can be independently combined. For example, in one embodiment of the present invention, the draft ratio [Tt / Ft] is preferably 1 to 30, more preferably 2 to 28, even more preferably 4 to 26, even more preferably 8 to 24, even more preferably 10 to 22, and even more preferably 14 to 20.

[0078] [Uses of Thermoplastic Polyolefin Films] The thermoplastic polyolefin film according to one embodiment of the present invention and the thermoplastic polyolefin film obtained by the method for producing the thermoplastic polyolefin film have excellent thermoformability and heat resistance. Therefore, they can be used in a variety of applications, such as films for film capacitors, films for high-frequency circuit substrates, films for transparent substrates, insulating films, thermoforming films, packaging films, optical films, surface protection films, process films, release films, films for sanitary materials, agricultural films, construction films, medical films, and fuel cell films. The TPO film is particularly excellent in thermoformability and heat resistance, and is therefore preferably used as a thermoforming film. Furthermore, when the thermoplastic polyolefin film is used as a fuel cell film, it is preferably used as a fuel cell sealing film that seals the gap between the cathode separator and the anode separator in a power generation cell for the fuel cell. In particular, when a sealing film for a fuel cell is required to have better sealing properties with the power-generating cell of the fuel cell, a laminate having a layer structure of adhesive layer / thermoplastic polyolefin film / adhesive layer, with adhesive layers on both sides of the thermoplastic polyolefin film, is preferred, and a laminate having the above layer structure is more preferred. The thermoplastic polyolefin film can also be suitably used as a gasket or packing. When the thermoplastic polyolefin film is used for gasket or packing applications, it is preferable to use the thermoplastic polyolefin film after punching, for example. In particular, when the thermoplastic polyolefin of the present invention is a 3-methyl-1-butene polymer, it has good thermoformability and heat resistance as well as excellent chemical resistance, and therefore can be suitably used as a sealing gasket or packing such as a gasket for a battery, a gasket for connecting a piping flange, or an in-vehicle packing. In one embodiment of the present invention, when the TPO film is used as a gasket or packing, the thickness of the TPO film is preferably 100 to 1,000 μm, more preferably 500 to 1,000 μm, and even more preferably 750 to 1,000 μm.Furthermore, when the TPO-based film further has a surface roughness Ra of 1,000 nm or less and an internal haze of 12.0% or less, it also has good optical properties and can be preferably used as an optical film in this case. Examples of the optical film include protective films for displays of electronic devices such as personal computers (PCs), various televisions, notebook PCs, tablet PCs, smartphones, and tablet terminals, as well as automotive meter panels; window glass; etc.

[0079] The present embodiment will be described in more detail below with reference to examples, but the present embodiment is not limited to these examples.

[0080] The physical properties of the copolymer (A) obtained in Production Example 1 were measured or evaluated by the following methods.

[0081] [Content of structural units derived from comonomer (1-decene)] The content of structural units derived from 1-decene (comonomer) in the copolymer (A) obtained in Production Example 1 was determined by IR measurement using an FT-IR (manufactured by Agilent Technologies, device name "Cary 600 series FTIR spectrometer") by the ATR method, as follows: 3-methyl-1-butene homopolymer and 1-decene homopolymer were mixed in any ratio, and the bending vibration of 1,461 cm derived from the main chain methylene group of each polymer was measured. －１ and a bending vibration of 727 cm due to the side chain methylene group derived from 1-decene. －１ A calibration curve was created from the ratio of the peak area of ​​the copolymer (A) obtained in Production Example 1 to the peak area of ​​the structural unit derived from 1-decene, and the mixing ratio of each resin. The IR measurement was performed on the copolymer (A) obtained in Production Example 1, and the obtained measured values ​​were inserted into the calibration curve to determine the content of the structural unit derived from 1-decene.

[0082] [Melting Point] Using a differential scanning calorimeter ("DSC25" manufactured by TA Instruments), the copolymer (A) obtained in Production Example 1 was heated from 30° C. to 320° C. at a rate of 10° C. / min under a nitrogen atmosphere (nitrogen flow rate 100 mL / min), held at 320° C. for 5 minutes, and then cooled to −70° C. at a rate of 10° C. / min. The peak temperature when the temperature was raised to 320° C. at 10° C. / min after holding at −70° C. for 5 minutes was measured, and this temperature was taken as the melting point.

[0083] [Melt Viscosity] The melt viscosity (Pa·s) of the copolymer (A) obtained in Production Example 1 was measured using a capillary rheometer ("Capilograph (registered trademark) 1C" manufactured by Toyo Seiki Seisaku-sho, Ltd.) at a barrel temperature of 320°C and a shear rate of 100 sec. －１ The measurement was carried out under the following conditions: (capillary: inner diameter 1.0 mm x length 10 mm, extrusion speed 10 mm / min).

[0084] [Catalyst Preparation] The catalyst component used in Production Example 1 was prepared by the following method. (Preparation of Titanium Catalyst Component) 47.6 g (500 mmol) of anhydrous magnesium chloride, 250 ml of decane, and 234 ml (1.5 mol) of 2-ethylhexyl alcohol were heated and reacted at 130°C for 2 hours to obtain a homogeneous solution. The resulting homogeneous solution was cooled to room temperature (23°C) and then added dropwise over 1 hour to 2 L (18 mol) of titanium tetrachloride maintained at -20°C to obtain a mixed solution. After completion of the dropwise addition of the homogeneous solution, the temperature of the resulting mixed solution was raised to 90°C over 2 hours. When the temperature reached 90°C, 11.4 mL (80 mmol) of ethyl benzoate was added and the mixture was maintained at the same temperature for 2 hours with stirring. After completion of the 2-hour reaction, the mixture was allowed to stand and the supernatant was removed. Decane and hexane were added, and the solids were washed three times. After that, the solids were resuspended in 2 L of titanium tetrachloride and again subjected to a heating reaction at 90°C for 2 hours. After the reaction was complete, the mixture was again left to stand using decane and hexane, and the supernatant was repeatedly removed, followed by thorough washing until no free titanium compound was detected in the washings. The resulting suspension was dried under reduced pressure at room temperature for 6 hours to obtain a titanium catalyst component. The composition of the resulting titanium catalyst component was 4.0 mass% titanium, 56.0 mass% chlorine, 17.0 mass% magnesium, 10.4 mass% ethyl benzoate, and 12.6 mass% hydrocarbon solvent consisting of decane and hexane.

[0085] [Production Example 1] (Production of Copolymer (A)) 8.0 kg of 3-methyl-1-butene, 0.6 kg of 1-decene, 50 g of triethylaluminum diluted with hexane to a concentration of 1 mol / L, and 4 g of the titanium catalyst component prepared in the above [Catalyst Preparation] were added to a 20 L stainless steel autoclave, and a polymerization reaction was carried out at 70°C for 4 hours. During the polymerization reaction, hydrogen was continuously supplied at a rate of 40 mL / min. After 4 hours, 200 g of 3-methyl-1-butanol was injected to stop the reaction and expel excess unreacted monomer. Next, 2 kg of normal heptane was introduced, and the mixture was stirred at 60°C for 30 minutes, after which the solids were filtered off using a pressure filter. This procedure was repeated twice, and then the solvent was changed from 2 kg of normal heptane to 3 kg of 2-propanol, and the same procedure was repeated twice. 7.7 kg of the obtained crude polymer was placed in a 50 L vessel equipped with a stirrer, followed by the addition of 8 kg of 1 mol / L hydrochloric acid and 16 kg of 2-propanol, followed by stirring for 1 hour. This suspension was filtered by vacuum filtration and washed with 10 kg of 2-propanol. The crude polymer obtained from this first washing was placed in a 50 L vessel equipped with a stirrer, followed by the addition of 20 kg of 2-propanol, followed by stirring for 1 hour. This suspension was filtered by vacuum filtration and washed with 10 kg of 2-propanol. The washed polymer obtained was dried under reduced pressure at 80°C for 2 days to obtain 3.2 kg of copolymer (A), a copolymer of 3-methyl-1-butene and 1-decene. The above-mentioned measurements were performed on the obtained copolymer (A), and the melting point was 286°C and the melt viscosity was 596 Pa s. Furthermore, the content of structural units derived from the comonomer 1-decene in copolymer (A) was 1.1 mol%.

[0086] Example 1 To 100 parts by mass of the copolymer (A) obtained in Production Example 1, 0.2 parts by mass of pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate] (antioxidant "ADK STAB (registered trademark) AO-60" manufactured by ADEKA Corporation), 0.2 parts by mass of 3,9-bis(2,6-di-t-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane (antioxidant "ADK STAB (registered trademark) PEP-36" manufactured by ADEKA Corporation), 2,4-di-t-amyl-6-[1-(3,5-di-t-amyl-2-hydroxyphenyl)ethyl]phenylacrylate 0.1 parts by mass of cellulose acetate (an alkyl radical scavenger "Sumilizer (registered trademark) GS", manufactured by Sumitomo Chemical Co., Ltd.) and 0.25 parts by mass of zinc stearate (an antacid) were dry-blended, and then nitrogen purging was performed using 99.99% pure nitrogen from the raw material inlet to prevent external oxygen contamination. While eliminating oxygen as much as possible, the dry-blended materials were charged into the raw material inlet and melted at a cylinder temperature of 295°C using a vented twin-screw kneading extruder "KZW15-45" (manufactured by Technovel Co., Ltd.). Water was removed by vacuuming the shear zone of the extruder using a vacuum pump, and pellet-shaped resin composition (M1) was obtained. The resulting pellet-shaped resin composition (M1) was molded under the following film-forming conditions to obtain a thermoplastic polyolefin film. Specifically, to prevent external oxygen contamination, nitrogen purging was performed using 99.99% pure nitrogen from the raw material inlet, and while oxygen was being removed as much as possible, the pellet-shaped resin composition (M1) was introduced into the raw material inlet, and the resin composition was melted at a cylinder temperature of 295°C using a vented twin-screw kneading extruder "KZW15-45" (manufactured by Technovel Co., Ltd.). After that, the extruder was evacuated from the shear section using a vacuum pump to remove moisture, and the melt was extruded into a film form from a T-die (gap thickness (Tt) of the lip of the T-die: 300 μm). The film was solidified on a casting drum maintained at a surface temperature of 170°C, yielding a thermoplastic polyolefin film with a thickness (Ft) of 50 μm. The draft ratio [Tt / Ft] was 6.

[0087] Examples 2 to 17 Thermoplastic polyolefin films were obtained in the same manner as in Example 1, except that the film-forming conditions were changed as shown in Table 1.

[0088] [Example 18] A thermoplastic polyolefin film was obtained under the same film-forming conditions as in Example 1, except that the pellet-shaped resin composition (M1) was not used and only the copolymer (A) obtained in Production Example 1 was used.

[0089] Example 19 A thermoplastic polyolefin film was obtained in the same manner as in Example 18, except that nitrogen purging was not performed during film formation.

[0090] Comparative Example 1 A mixture of 100 parts by mass of polypropylene (trade name "Novatec (registered trademark) PP MA3" manufactured by Japan Polypropylene Corporation) and 0.2 parts by mass of pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate] (antioxidant "ADK STAB (registered trademark) AO-60" manufactured by ADEKA Corporation), 0.2 parts by mass of 3,9-bis(2,6-di-t-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane (antioxidant "ADK STAB (registered trademark) PEP-36" manufactured by ADEKA Corporation), 2,4-di-t-amyl-6-[1-(3,5-di-t-amyl-2-hydroxyphenyl)ethyl]phenyl acrylate was used. After dry-blending 0.1 parts by weight of ethylenediamine acrylate (an alkyl radical scavenger "Sumilizer (registered trademark) GS", manufactured by Sumitomo Chemical Co., Ltd.) and 0.25 parts by weight of zinc stearate (antacid), 99.99% pure nitrogen was used to purge the raw material inlet as a measure to prevent oxygen contamination from the outside. While eliminating oxygen as much as possible, the dry-blended materials were added through the raw material inlet and melted at a cylinder temperature of 240 ° C. using a vented twin-screw kneading extruder "KZW15-45" (manufactured by Technovel Co., Ltd.). The extruder was then evacuated from the shear section using a vacuum pump to remove moisture, yielding a pellet-shaped resin composition (CM1). The resulting pellet-shaped resin composition (CM1) was molded under the following film-forming conditions to obtain a polypropylene film. Specifically, as a measure to prevent external oxygen contamination, nitrogen purging was performed using 99.99% pure nitrogen from the raw material inlet, and while eliminating oxygen as much as possible, the pellet-shaped resin composition (CM1) was introduced into the raw material inlet, and a vented twin-screw kneading extruder "KZW15-45" (manufactured by Technovel Co., Ltd.) was used to melt the resin composition at a cylinder temperature of 240 ° C., and then the extruder was evacuated from the shear section using a vacuum pump to remove moisture. The melt was extruded into a film from a T-die (gap thickness (Tt) of the lip of the T-die: 166.5 μm), and solidified on a casting drum maintained at a surface temperature of 40 ° C. to obtain a polypropylene film with a thickness (Ft) of 50 μm. The draft ratio [Tt / Ft] was 3.33.

[0091] Comparative Example 2 A thermoplastic polyolefin film was obtained in the same manner as in Comparative Example 1, except that the film-forming conditions were changed as shown in Table 2.

[0092] Comparative Example 3 An attempt was made to produce a polypropylene film in the same manner as in Comparative Example 1, except that the surface temperature of the casting drum during film production was set to 170° C. However, the film-like molten material extruded from the T-die fused to the surface of the casting drum, and a polypropylene film could not be produced.

[0093] Comparative Example 4 A mixture of 100 parts by mass of polymethylpentene (trade name "TPX (registered trademark) DX845" manufactured by Mitsui Chemicals, Inc.) and 0.2 parts by mass of pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate] (antioxidant "ADK STAB (registered trademark) AO-60" manufactured by ADEKA Corporation), 0.2 parts by mass of 3,9-bis(2,6-di-t-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane (antioxidant "ADK STAB (registered trademark) PEP-36" manufactured by ADEKA Corporation), 2,4-di-t-amyl-6-[1-(3,5-di-t-amyl-2-hydroxyphenyl)ethyl]phenyl acrylate was used. After dry-blending 0.1 parts by weight of methyl acrylate (an alkyl radical scavenger "Sumilizer (registered trademark) GS", manufactured by Sumitomo Chemical Co., Ltd.) and 0.25 parts by weight of zinc stearate (antacid), a nitrogen purge was performed using 99.99% pure nitrogen from the raw material inlet to prevent external oxygen contamination. While eliminating oxygen as much as possible, the dry-blended materials were added through the raw material inlet and melted at a cylinder temperature of 270 ° C. using a vented twin-screw kneading extruder "KZW15-45" (manufactured by Technovel Co., Ltd.). After removing moisture by vacuuming the shear section of the extruder using a vacuum pump, pelletized resin composition (CM2) was obtained. The resulting pelletized resin composition (CM2) was molded under the following film-forming conditions to obtain a polymethylpentene film. Specifically, as a measure to prevent external oxygen contamination, nitrogen purging was performed using 99.99% pure nitrogen from the raw material inlet, and while eliminating oxygen as much as possible, the pellet-shaped resin composition (CM2) was introduced into the raw material inlet, and a vented twin-screw kneading extruder "KZW15-45" (manufactured by Technovel Co., Ltd.) was used to melt the resin composition at a cylinder temperature of 270 ° C., and then the extruder was evacuated from the shear section using a vacuum pump to remove moisture. The melt was extruded into a film from a T-die (gap thickness (Tt) of the lip of the T-die: 166.5 μm), and solidified on a casting drum maintained at a surface temperature of 80 ° C. to obtain a polymethylpentene film with a thickness (Ft) of 50 μm. The draft ratio [Tt / Ft] was 3.33.

[0094] Comparative Examples 5 and 6 Thermoplastic polyolefin films were obtained in the same manner as in Example 19, except that the film-forming conditions were changed as shown in Table 2.

[0095] Comparative Example 7 A thermoplastic polyolefin film was obtained in the same manner as in Example 1, except that the film-forming conditions were changed as shown in Table 2.

[0096] Comparative Example 8 A biaxially stretched cycloolefin polymer film (trade name "ZEONORFILM (registered trademark) L24", manufactured by Zeon Corporation) was used as the thermoplastic polyolefin film.

[0097] The physical properties of the films obtained in the examples and comparative examples were measured or evaluated by the following methods.

[0098] [Film Thickness] The film was cut from the center of the TD direction to a size of 100 mm in the TD direction x 100 mm in the MD direction to prepare a film sample. The thickness was measured at 11 points at 10 mm intervals from both ends of the TD film using a dial gauge thickness meter (JIS B7503:2017 compliant, manufactured by Ozaki Seisakusho Co., Ltd., "PEACOCK (registered trademark) UPRIIGHT DIAL GAUGE (graduation 0.001 mm, measurement range 2 mm, model No. 25, 5 mmφ flat probe)"), and the average value was used as the film thickness. The MD direction ("MD" is an abbreviation for Machine Direction) corresponds to the longitudinal direction of the film roll during film production. The TD direction ("TD" is an abbreviation for Transverse Direction) refers to the direction perpendicular to the MD direction. The same applies below.

[0099] [Storage Modulus E'] Based on JIS K7244-1:1998, the storage modulus E' of the film at each temperature (70°C, 150°C, 270°C) was determined using a dynamic viscoelasticity measuring device "Rheogel-E4000" manufactured by UBM Corporation. Measurement was performed only in the MD direction of the film under the following conditions, and the average value of the results of three measurements was taken as the storage modulus E' of the film. - Measurement method: Dynamic viscoelasticity measurement (sine wave) - Measurement mode: Temperature dependency - Chuck: Tensile - Waveform: Sine wave - Vibration type: Stop vibration - Chuck distance: 10 mm - Test piece width: 5 mm - Frequency: 1 Hz - Measurement temperature: -50°C to 300°C - Heating rate: 3°C / min - Measurement atmosphere: In air

[0100] [Heat Resistance] The film was cut into a size of 100 mm x 100 mm to prepare a film sample, which was then left for 24 hours under atmospheric conditions of 25°C and 65% RH without any load applied to it, thereby conditioning the humidity of the film sample. After conditioning, the film sample was left in a hot air oven at 240°C for 30 minutes, then removed, and left under atmospheric conditions of 23°C and 50% RH for 30 minutes or more. The change in appearance of the film sample before and after placing it in the hot air oven was visually evaluated according to the following evaluation criteria. A rating of "S" is the best. A rating of "A" or "B" was considered to be a film with good heat resistance. [Evaluation: Criteria] "S": No noticeable change in the appearance of the film was observed. "A": Minor changes were observed in the film (such as curling, unevenness, or swelling). "B": Changes greater than rating "A" were observed in the film (such as curling, unevenness, or swelling). "C": Significant changes (such as curling, unevenness, or swelling) are observed in the film that are greater than those in the "B" grade. "D": Significant changes are observed in the film that are greater than those in the "C" grade, such as melting or significant shrinkage.

[0101] [Thermoformability] According to the following method specified in ASTM-D882, a precision universal testing machine (Shimadzu Corporation, Autograph (registered trademark) "AG-2000B") was used to set a 10 mm wide film sample so that the chuck length was 50 mm. The sample was held for 20 seconds in a thermostatic chamber previously adjusted to a temperature of 210 ° C., and then a tensile test was performed at 210 ° C. and a pulling rate of 100 mm / min. The tensile elongation at break at 210 ° C. was measured five times in the MD direction of the film, and the average of the five measurements was used as the tensile elongation at break in the MD direction of the film, and was evaluated as an index of thermoformability at high temperatures. The rating "S" is the best. Furthermore, if the rating is "A" or "B," the film has good thermoformability, and the rating "A" is better than the rating "B." [Measurement conditions] Film sample size: Width 10 mm x length 100 mm (length direction corresponds to MD direction) Distance between chucks: 50 mm Pulling speed: 100 mm / min [Evaluation: Criteria] "S": Has a tensile breaking elongation of 200% or more. "A": Has a tensile breaking elongation of 100% or more. "B": Has a tensile breaking elongation of 10% or more but less than 100%. "C": Has a tensile breaking elongation of less than 10%, or measurement was difficult for the following reasons: The film sample curled too much to set the film in the measurement chuck, or the film was fused to the measurement chuck.

[0102] [Flatness (Curling)] The film was cut into a size of 100 mm x 100 mm to prepare a film sample, which was then left for 24 hours under an atmospheric condition of 25°C and 65% RH without any load being applied to the film sample, thereby conditioning the film sample. After conditioning, the film sample was placed on a flat surface without any tape on all four sides (the casting drum surface of the film sample was the surface in contact with the desk), and the "floating" of the film from the desk was measured to evaluate the flatness. The "floating" refers to the height (distance) of the most raised part of the film placed on the desk from the contact surface, with the contact surface between the desk and the film being set at 0 mm. This "floating" was used as the "curling" value (unit: mm), which is an index for evaluating flatness. A smaller curling value indicates better flatness.

[0103] [Transmission YI (D65)] The yellowness index (YI value) of the film was measured using a spectrophotometer "SD7000" manufactured by Nippon Denshoku Industries Co., Ltd. under the condition of a D65 light source (viewing angle 10 degrees). After background measurement was performed without a sample, the film was set in a sample holder and transmittance measurement was performed for light of 380 nm to 780 nm to determine the tristimulus values ​​(X, Y, Z). The YI value was calculated based on the following formula. Three measurements were performed, and the average of the results of each of the three measurements was taken as the yellowness index (YI value) of the film. This value is shown in Tables 1 and 2 below as the transmission YI (D65). The smaller the yellowness index (YI value) of the film, the better. YI = 100 × (1.2769X - 1.0592Z) / Y

[0104] [Surface roughness Ra] The film surface was measured by scanning 5,000 μm in the TD direction using a stylus surface profiler "Dektak (registered trademark) 150" manufactured by Bruker Nano under the following conditions: Measurements were taken three times for the surface in contact with the casting drum and the surface not in contact with the casting drum, and the average of the six measurements was taken as the surface roughness Ra (unit: nm) of the film. Scan Type: Standard scan Scan Length: 5,000 μm Duration: 60 sec Range: 524 μm Profile: Hills & Valleys Stylus Type: 12.5 μm Stylus Force: 3.0 mg Cutoff value when removing waviness: 200 μm

[0105] [Internal Haze] The internal haze of the film was measured using a haze meter ("NDH5000" manufactured by Nippon Denshoku Industries Co., Ltd.) according to JIS K7136:2000. Specifically, in order to cancel scattering on the film surface, the measurement was performed with the test piece (film) immersed in a quartz cell filled with glycerin. The haze value of the quartz cell filled with glycerin and the test piece immersed in it was subtracted from the haze value of the quartz cell filled with glycerin and the test piece immersed in it, and a value was calculated. The measurement and calculation of the value were performed five times, and the average of the calculated values ​​for the five measurements was taken as the internal haze of the film.

[0106] [Evaluation as an Optical Film] The film was cut into a size of 100 mm x 100 mm to prepare a film sample. The film sample was placed on the surface of an organic EL display and observed from the front and oblique angles under LED fluorescent lighting to confirm its visibility and evaluate it as an optical film. Curled film samples were secured with tape on all four sides to ensure the flatness of the film as much as possible during evaluation. The following judgment was made by 10 people, and the result of the most common evaluation was adopted. If multiple most common evaluation results were obtained, the poorest evaluation result was adopted. However, the evaluation results of all the people were consistent in the evaluations of Examples 1 to 19 and Comparative Examples 1 to 8. Furthermore, a polyester film "Lumirror (registered trademark) #50-T60" manufactured by Toray Industries, Inc. was used as a reference sample to standardize the evaluation criteria. Of the following evaluation results, an "S" evaluation was considered to be the best. Furthermore, a film receiving an "A" or "B" evaluation was considered to have satisfactory optical properties suitable for use as an optical film. [Judgment: Standard] "S": The screen of the organic EL display is visible at least as clearly as when the standard sample is used. "A": The screen of the organic EL display appears slightly cloudy, and visibility is slightly poorer. "B": The screen of the organic EL display appears cloudy, and visibility is poor (poorer than rating "A"). "C": The screen of the organic EL display appears cloudy, and visibility is significantly poorer (poorer than rating "B").

[0107] [Film handling] Fifty film samples measuring 210 mm in the TD direction x 297 mm in the MD direction were cut from the center of the film in the TD direction to prepare film samples. The 50 samples were naturally stacked without applying any load to the film samples and left for 24 hours under atmospheric conditions of 25°C and 65% RH to condition the film samples. The film samples after humidity conditioning were placed in a stack of 50 sheets in the paper feed section of a UV offset sheet-fed press. To print solid patterns on all 50 sheets of film, the presence or absence of multi-feeding was visually observed as each film was fed from the paper feed section into the press, and the film handling was evaluated. A rating of "S" was the best. A rating of up to "A" was considered to indicate good handling. "Multi-feeding" refers to the phenomenon in which two or more films are fed into the press while overlapping each other. [Evaluation: Criteria] "S": No double feeding occurred when feeding the film, and no signs of double feeding were observed. "A": No double feeding occurred when feeding the film, but signs of double feeding were occasionally observed. "B": Double feeding was observed when feeding the film. "C": The film had poor flatness, making it difficult to feed 50 sheets stacked together into the printing machine.

[0108] [Chemical Resistance] According to the method specified in JIS K7114:2001, the film was cut into a size of 20 mm x 20 mm to prepare a sample. The pre-test weight of the sample was measured, and then the sample was immersed in a chloroform solution at 23°C for one week. After one week, the sample was removed from the chloroform solution and dried for two hours using a vacuum dryer ("DP33" manufactured by Yamato Scientific Co., Ltd.) at a temperature of 50°C and a vacuum of -0.1 MPa. Immediately after the drying process, the post-test weight of the sample was measured. If the increase or decrease rate of the post-test weight of the sample relative to the pre-test weight was less than 50%, the chemical resistance was evaluated as "superior," and if it was 50% or more, the chemical resistance was evaluated as "inferior."

[0109]

[0110]

[0111] In Table 2, the notation "(*1)" indicates that the film-like molten material after extrusion was fused to the casting drum, making film formation impossible and therefore evaluation was not possible. In Tables 1 and 2, the following abbreviations in the "Resin Composition" column represent the following: P3MB (100): 100% by mass of the total polymers in the resin composition is 3-methyl-1-butene polymer (copolymer (A) obtained in Production Example 1). PP (100): 100% by mass of the total polymers in the resin composition is polypropylene. TPX (100): 100% by mass of the total polymers in the resin composition is polymethylpentene. Biaxially oriented COP (100): Biaxially oriented cycloolefin polymer film. In Tables 1 and 2, "antioxidant, etc." refers to antioxidants, alkyl radical scavengers, and antacids. Therefore, in each example, the notation "present" for "antioxidant, etc." means that the antioxidants, alkyl radical scavengers, and antacids used in Example 1 are contained in the same manner. On the other hand, in Examples 18 and 19 and Comparative Examples 5 and 6, the notation "absent" for "antioxidant, etc." means that none of the antioxidants, alkyl radical scavengers, and antacids are contained.

[0112] The results in Table 1 confirm that the thermoplastic polyolefin films of Examples 1 to 19 have a storage modulus E' of 50 MPa or more at 150°C and a storage modulus E' of 1 MPa or more at 270°C, and therefore can achieve both good heat resistance and thermoformability compared to the thermoplastic polyolefin films of each comparative example. On the other hand, the results in Table 2 confirm that the thermoplastic polyolefin films of Comparative Examples 1, 2, and 5 to 7 have a storage modulus E' of less than 50 MPa at 150°C and a storage modulus E' of less than 1 MPa at 270°C, and therefore are inferior in both heat resistance and thermoformability compared to the thermoplastic polyolefin films of each example. Furthermore, the thermoplastic polyolefin films of Comparative Examples 4 and 8 have a storage modulus E' of less than 1 MPa at 270°C, and therefore are inferior in both heat resistance and thermoformability compared to the thermoplastic polyolefin films of each example. Furthermore, in Comparative Example 3, as mentioned above, when the surface temperature of the casting drum during film formation was set to 170°C, the film-like molten material extruded from the T-die fused to the surface of the casting drum, making it impossible to form a film.

[0113] Furthermore, from the results in Table 1, it was confirmed that the thermoplastic polyolefin-based films of Examples 1 to 16, 18, and 19 had a surface roughness Ra of 1,000 nm or less and an internal haze of 12.0% or less, and therefore had better handleability than the thermoplastic polyolefin-based films of each comparative example. Furthermore, since the surface roughness Ra was 1,000 nm or less and the internal haze was 12.0% or less, it was confirmed that they had good optical properties sufficient for use as optical films. Furthermore, it was confirmed that the TPO-based films of these examples had small transmission YI values ​​and little yellowing, confirming that the TPO-based films can achieve good visibility from the standpoint of color when used as optical films. Furthermore, from the results in Table 2, the thermoplastic polyolefin films of Comparative Examples 5 to 7 had a surface roughness Ra of more than 1,000 nm and an internal haze of more than 12.0%, and therefore, compared to the thermoplastic polyolefin films of Examples 1 to 16, 18, and 19, it was confirmed that the film handling properties were inferior and that the optical properties were not sufficient to enable use as optical films.

[0114] The thermoplastic polyolefin film of Example 17 had superior chemical resistance. On the other hand, the thermoplastic polyolefin film of Comparative Example 2 had inferior chemical resistance. Therefore, the thermoplastic polyolefin film containing a 3-methyl-1-butene polymer of Example 17 can also be preferably used as a gasket or packing that requires sealing properties.

Claims

1. A thermoplastic polyolefin-based film formed from a resin composition containing a thermoplastic polyolefin as a main component, having a storage modulus E' of 50 MPa or more at 150°C and a storage modulus E' of 1 MPa or more at 270°C.

2. The thermoplastic polyolefin film according to claim 1, having a storage modulus E' at 70°C of 1,000 MPa or less.

3. The thermoplastic polyolefin film according to claim 1 or 2, having a surface roughness Ra of 1,000 nm or less.

4. The thermoplastic polyolefin film according to any one of claims 1 to 3, having an internal haze of 12.0% or less.

5. The thermoplastic polyolefin film according to any one of claims 1 to 4, having a yellowness index (YI) of 3.50 or less.

6. The thermoplastic polyolefin film according to any one of claims 1 to 5, wherein the thermoplastic polyolefin is a 3-methyl-1-butene polymer.

7. The thermoplastic polyolefin film according to claim 6, wherein the 3-methyl-1-butene polymer is at least one selected from the group consisting of 3-methyl-1-butene homopolymers and copolymers of 3-methyl-1-butene with at least one selected from the group consisting of ethylene and α-olefins having 3 to 20 carbon atoms other than 3-methyl-1-butene.

8. The thermoplastic polyolefin film according to claim 6 or 7, wherein the content of the 3-methyl-1-butene polymer is 50.0% by mass or more in 100% by mass of the total amount of the resin composition.

9. The thermoplastic polyolefin film according to any one of claims 1 to 8, wherein the resin composition contains an antioxidant.

10. A method for producing a thermoplastic polyolefin film, comprising step (I) of melt-extruding a resin composition containing a thermoplastic polyolefin as a main component, to produce a thermoplastic polyolefin film having a storage modulus E' at 150°C of 50 MPa or more and a storage modulus E' at 270°C of 1 MPa or more.

11. The method for producing a thermoplastic polyolefin film according to claim 10, wherein in step (I), the resin composition containing the thermoplastic polyolefin as a main component is melted in an inert atmosphere or in a low-oxygen state.

12. The method for producing a thermoplastic polyolefin film according to claim 10 or 11, wherein in step (I), the resin composition containing the thermoplastic polyolefin as a main component is melted at 280 to 323°C.

13. A method for producing a thermoplastic polyolefin film according to any one of claims 10 to 12, comprising a step (II) of contacting the molten extrudate of a resin composition containing the thermoplastic polyolefin as a main component obtained in step (I) with a casting drum, wherein the temperature of the casting drum is 40 to 250°C.

14. A method for producing a thermoplastic polyolefin film according to any one of claims 10 to 13, wherein in step (I), a melt of a resin composition containing the thermoplastic polyolefin as a main component is extruded through a T-die, and a draft ratio [Tt / Ft], which is the ratio of a gap thickness (Tt) at the lip of the T-die to a thickness (Ft) of the resulting thermoplastic polyolefin film, is 1 to 30.

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