Insulating film, copper-clad laminate, and millimeter-wave antenna

Abstract

This insulating film contains a material including a 3-methyl-1-butene polymer, and the dielectric tangent of the insulating film at 10 to 300 GHz is less than 0.00070.

Description

Insulating film, copper clad laminate, and millimeter wave antenna

[0001] The present invention relates to an insulating film, a copper-clad laminate including the insulating film, and a millimeter-wave antenna including the copper-clad laminate.

[0002] As electrical and electronic devices become more powerful and functional, vehicles such as automobiles and buses are equipped with radars such as long-range radars (LRRs) and short-range radars (SRRs). To meet the demands of a society where high-capacity, high-speed communications are becoming a reality, radars are required to detect radio waves in the high-frequency range exceeding 10 GHz, for example, millimeter waves (frequency bands of 30 GHz to 300 GHz). Radars typically consist of an antenna and a housing enclosing the antenna. Materials used for the antenna and housing have traditionally been required to have excellent dielectric properties suitable for use in high-frequency ranges, and polyphenylene ethers, maleimide triazine resins, and the like have been used. Other resins known to have excellent dielectric properties include polyolefin resins such as polypropylene and fluororesins such as polytetrafluoroethylene. For example, Patent Document 1 discloses a high-frequency dielectric antenna made of a resin composition containing a crystalline hydrogenated cyclic olefin ring-opening polymer having a repeating unit derived from a polycyclic norbornene monomer and a glass filler. Furthermore, Patent Document 2 discloses a double-sided metal-clad dielectric substrate for a planar antenna, which is characterized in that the entire back surface of the dielectric substrate is a ground conductor, and a metal foil for forming a circularly polarized radiation microstrip element is provided on the surface, and the dielectric layer contains a homopolymer of 3-methylbutene-1 or a copolymer of 3-methylbutene-1 and an olefin and / or polyene having 2 to 12 carbon atoms.

[0003] JP 2013-256596 A JP 63-086320 A

[0004] An insulating material such as an insulating film is used for the antenna substrate that constitutes the antenna. For example, an antenna including an insulating film made of polyphenylene ether or maleimide triazine resin can be used in the several GHz band without any problems, but has problems such as large transmission loss when used in the several tens of GHz band. The dielectric for a planar antenna disclosed in Patent Document 2 has a dielectric constant of 2.2 and a dielectric loss tangent of 10 at a frequency of 12 GHz. －３ It is described that the dielectric properties of the dielectric material are excellent. However, even with the dielectric material for planar antennas described above, there is a risk of transmission loss when used in the millimeter wave band, which is a high frequency band, and there is room for improvement. Therefore, new materials with even better dielectric properties are desired. Furthermore, polyolefin resins such as polypropylene have poor heat resistance and cannot withstand manufacturing processes such as reflow soldering. Patent Document 1 describes that polyolefin resins can withstand high temperatures such as reflow soldering by using glass fillers, but further improvement in reflow heat resistance is required. Furthermore, fluororesins such as polytetrafluoroethylene have poor moldability, low productivity, and are expensive.

[0005] In view of the current situation, an object of the present invention is to provide an insulating film that can provide a millimeter-wave antenna having a low dielectric constant and a low dielectric loss tangent, as well as excellent formability and reflow heat resistance; a copper-clad laminate including the insulating film; and a millimeter-wave antenna including the copper-clad laminate.

[0006] As a result of intensive research to solve the above problems, the present inventors have conceived the following invention and found that the above problems can be solved.

[0007] [1] An insulating film containing a material containing a 3-methyl-1-butene polymer, the dielectric loss tangent being less than 0.00070 at 10 GHz to 300 GHz. [2] The insulating film according to [1], 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 ethylene or an α-olefin, the α-olefin having 3 to 20 carbon atoms. [3] The insulating film according to [2], wherein the copolymer contains structural units derived from ethylene or the α-olefin in a proportion of more than 0 mol % and not more than 20 mol %. [4] The insulating film according to [2] or [3], wherein the copolymer contains structural units derived from ethylene or the α-olefin in a proportion of more than 0 mol % and not more than 10 mol %. [5] The insulating film according to any one of [1] to [4] above, wherein the 3-methyl-1-butene polymer has a melting point of 260 to 310°C. [6] The insulating film according to any one of [1] to [5] above, wherein the material is a resin composition containing the 3-methyl-1-butene polymer and an alkyl radical scavenger. [7] The insulating film according to [6] above, wherein the alkyl radical scavenger includes at least one selected from the group consisting of an acrylic phenol compound and a benzofuranone compound. [8] A copper-clad laminate comprising the insulating film according to any one of [1] to [7] above. [9] A millimeter-wave antenna comprising the copper-clad laminate according to [8] above.

[10] A millimeter-wave antenna comprising the insulating film according to any one of [1] to [7] above.

[0008] According to the present invention, it is possible to provide an insulating film that has a low relative dielectric constant and a low dielectric loss tangent, and is excellent in formability and reflow heat resistance, and that can provide a millimeter-wave antenna that is excellent in reflow heat resistance; a copper-clad laminate including the insulating film; and a millimeter-wave antenna including the copper-clad laminate.

[0009] The following is a description based on one example of an embodiment of the present invention. However, the embodiment shown below is an example for embodying the technical idea of ​​the present invention, and the present invention is not limited to the following description. In this specification, preferred embodiments are shown, but a combination of two or more of the individual preferred embodiments is also a preferred embodiment. For matters shown as numerical ranges, when there are several numerical ranges, the lower limit and upper limit can be selectively combined to form a preferred embodiment. In this specification, when a numerical range is described as "XX to YY," it means "XX or more and YY or less."

[0010] <Insulating Film> The insulating film of this embodiment contains a material containing a 3-methyl-1-butene polymer and is characterized by a dielectric loss tangent of less than 0.00070 at 10 GHz to 300 GHz. That is, the insulating film of this embodiment contains a 3-methyl-1-butene polymer. By including a 3-methyl-1-butene polymer in the material forming the insulating film, the insulating film has a low relative dielectric constant and low dielectric loss tangent, as well as excellent formability and reflow heat resistance. Furthermore, the material forming the insulating film of this embodiment has excellent heat resistance, allowing it to be formed into any shape. Furthermore, because the 3-methyl-1-butene polymer has a high melting point and low water absorption, the insulating film of this embodiment is less likely to warp, melt, or blister during reflow soldering. Furthermore, even when stored in a humid and hot environment, no blisters will occur during reflow soldering, making it expected to be easy to store and manage. Furthermore, because the 3-methyl-1-butene polymer has a relatively low specific gravity, the insulating film of this embodiment can also contribute to weight reduction.

[0011] The material used for the insulating film of this embodiment may be a 3-methyl-1-butene polymer, or may be a resin composition containing components other than the 3-methyl-1-butene polymer.

[0012] [Material] The material used for the insulating film of this embodiment includes a 3-methyl-1-butene polymer. That is, the insulating film of this embodiment contains a 3-methyl-1-butene polymer.

[0013] <3-Methyl-1-butene Polymer> The 3-methyl-1-butene polymer is a polymer containing at least a structural unit derived from 3-methyl-1-butene. The 3-methyl-1-butene polymer may be a 3-methyl-1-butene homopolymer or a copolymer of 3-methyl-1-butene and an unsaturated hydrocarbon. The unsaturated hydrocarbon may be one type or multiple types. Examples of the unsaturated hydrocarbon include ethylene or an α-olefin. In this embodiment, the α-olefin used in the 3-methyl-1-butene polymer refers to an α-olefin other than 3-methyl-1-butene. In other words, the α-olefin refers to an α-olefin other than 3-methyl-1-butene, and is also expressed as α-olefin (excluding 3-methyl-1-butene). From the viewpoint of good copolymerizability, the unsaturated hydrocarbon is preferably ethylene or an α-olefin having 3 to 20 carbon atoms. The α-olefin having 3 to 20 carbon atoms may be one type or multiple types. From the viewpoint of favorably exhibiting mechanical properties (adequate strength, flexibility, and impact resistance), 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 ethylene or an α-olefin having 3 to 20 carbon atoms, and more preferably a copolymer of 3-methyl-1-butene with ethylene or an α-olefin having 3 to 20 carbon atoms. A copolymer of 3-methyl-1-butene with ethylene or an α-olefin having 3 to 20 carbon atoms refers to a copolymer of 3-methyl-1-butene with ethylene or a copolymer of 3-methyl-1-butene with an α-olefin having 3 to 20 carbon atoms. Hereinafter, a copolymer of 3-methyl-1-butene with ethylene or an α-olefin will also be referred to simply as a "copolymer." The copolymer may be a random copolymer, a block copolymer, or an alternating copolymer. The method for producing the copolymer is not limited as long as it does not impair the effects of the present invention, and known copolymerization methods can be used.

[0014] When the 3-methyl-1-butene polymer is the copolymer, the content of structural units derived from ethylene or an α-olefin in 100 mol% of the copolymer is preferably more than 0 mol% and not more than 20 mol%. From the viewpoints of flexibility and impact resistance, the content of structural units derived from ethylene or an α-olefin in 100 mol% of the copolymer is more preferably 0.1 mol% or more, and even more preferably 0.5 mol% or more. From the viewpoint of reflow heat resistance, the content of structural units derived from ethylene or an α-olefin in 100 mol% of the copolymer is more preferably 15 mol% or less, and even more preferably 10 mol% or less. From these viewpoints, the content of structural units derived from ethylene or an α-olefin in 100 mol% of the copolymer is more preferably 0.1 to 15 mol%, and even more preferably 0.5 to 10 mol%. In one embodiment, the content of structural units derived from ethylene or an α-olefin in 100 mol% of the copolymer is more preferably more than 0 mol% and not more than 10 mol%. The content of structural units derived from ethylene or α-olefin in the copolymer can be determined by Fourier transform infrared spectrophotometer (FT-IR). Specifically, it can be measured by the method described in the examples.

[0015] When the 3-methyl-1-butene polymer is the copolymer, the content of structural units derived from 3-methyl-1-butene in 100 mol% of the copolymer is preferably 80 mol% or more and less than 100 mol%. From the viewpoint of reflow heat resistance, the content of structural units derived from 3-methyl-1-butene in 100 mol% of the copolymer is preferably more than 50 mol%, more preferably 70 mol% or more, even more preferably 85 mol% or more, more preferably 90 mol% or more, even more preferably 92 mol% or more, and still more preferably 93 mol% or more. Furthermore, from the viewpoints of flexibility and impact resistance, the content of structural units derived from 3-methyl-1-butene in 100 mol% of the copolymer is more preferably 99.9 mol% or less, even more preferably 99.5 mol% or less. From these viewpoints, the content of structural units derived from 3-methyl-1-butene in 100 mol% of the copolymer is preferably 85 to 99.9 mol%, more preferably 90 to 99.5 mol%, even more preferably 92 to 99.5 mol%, and still more preferably 93 to 99.5 mol%.

[0016] From the viewpoint of favorably exhibiting the physical properties of the 3-methyl-1-butene polymer, the ethylene or α-olefin is preferably an α-olefin having 3 to 20 carbon atoms, more preferably an α-olefin having 4 to 16 carbon atoms, more preferably an α-olefin having 4 to 12 carbon atoms, still more preferably an α-olefin having 4 to 10 carbon atoms, and still more preferably an α-olefin having 6 to 10 carbon atoms. The α-olefin may be linear, branched, cyclic, or may contain a cyclic moiety.

[0017] 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-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, 1-eicosene, vinylcyclohexene, and vinylnorbornane. The α-olefin having 3 to 20 carbon atoms is preferably a linear α-olefin, more preferably at least one selected from the group consisting of 1-butene, 1-octene, 1-nonene, and 1-decene, even more preferably at least one selected from the group consisting of 1-octene, 1-nonene, and 1-decene, and still more preferably 1-decene. The α-olefin having 2 to 20 carbon atoms, i.e., ethylene or an α-olefin having 3 to 20 carbon atoms, may be used alone or in combination of two or more.

[0018] The melting point of the 3-methyl-1-butene polymer is preferably 260 to 310°C. When the melting point of the 3-methyl-1-butene polymer is within the above range, the material used for the insulating film can be easily molded by extrusion molding or the like, and the reflow heat resistance of the millimeter-wave antenna can be improved. The melting point of the 3-methyl-1-butene polymer refers to the peak temperature measured using a differential scanning calorimeter by heating a test piece (3-methyl-1-butene polymer) from 30°C to 320°C at a rate of 10°C / min under a nitrogen flow rate (100 mL / min), holding at 320°C for 5 minutes, cooling to -70°C at 10°C / min, holding at -70°C for 5 minutes, and then heating to 320°C at a rate of 10°C / min. Specifically, the melting point can be measured by the method described in the Examples. From the viewpoint of the balance between production efficiency and reflow heat resistance, the melting point of the 3-methyl-1-butene polymer is more preferably 270 to 305°C, even more preferably 280 to 305°C, and still more preferably 280 to 300°C.

[0019] The melt viscosity of the 3-methyl-1-butene polymer of this embodiment is preferably 10 to 1,000 Pa s. When the melt viscosity of the 3-methyl-1-butene polymer is 10 Pa s or more, the mechanical strength is further improved, and when it is 1,000 Pa s or less, good fluidity during molding is easily obtained. From the viewpoint of the balance between mechanical strength and fluidity during molding, the melt viscosity of the 3-methyl-1-butene polymer is more preferably 30 to 500 Pa s, even more preferably 50 to 300 Pa s, still more preferably 50 to 200 Pa s, and even more preferably 70 to 150 Pa s. The melt viscosity of the 3-methyl-1-butene polymer of this embodiment is measured using a capillary rheometer at a barrel temperature of 320°C and a shear rate of 1,220 sec. －１ The term "capillary" refers to a value measured under the conditions of (capillary: inner diameter 1.0 mm x length 10 mm, extrusion rate 10 mm / min), and specifically can be measured by the method described in the examples.

[0020] From the viewpoints of formability and reflow heat resistance, the content of the 3-methyl-1-butene polymer in 100% by mass of the material used in the insulating film is preferably 80.0 to 99.9% by mass, more preferably 85.0 to 99.9% by mass, and even more preferably 90.0 to 99.9% by mass. Because 3-methyl-1-butene has a high melting point, increasing the proportion of 3-methyl-1-butene tends to improve the reflow heat resistance of the millimeter-wave antenna. The content of the 3-methyl-1-butene polymer in the insulating film is the same as above.

[0021] 3-methyl-1-butene polymers have a relatively low specific gravity and can contribute to weight reduction of insulating films. Furthermore, 3-methyl-1-butene polymers do not generate harmful gases when incinerated. Furthermore, the decomposition products of 3-methyl-1-butene polymers in an inert atmosphere are low-molecular-weight hydrocarbons, making them suitable for chemical recycling.

[0022] [Resin Composition] The material contained in the insulating film of this embodiment includes a 3-methyl-1-butene polymer. The material contained in the insulating film of this embodiment may also be a resin composition. Therefore, the "material" and "resin composition" contained in the insulating film of this embodiment are synonymous.

[0023] <Alkyl Radical Scavenger> From the viewpoint of exhibiting even better dielectric and mechanical properties, the material used for the insulating film may be a resin composition containing the above-mentioned 3-methyl-1-butene polymer and an alkyl radical scavenger. In this case, the insulating film of this embodiment also contains an alkyl radical scavenger, its reaction product, or its decomposition product. In this embodiment, the term "alkyl radical scavenger" refers to a compound that reacts with an alkyl radical derived from the 3-methyl-1-butene polymer and subsequently stabilizes the radical, thereby suppressing chain-like main-chain scission reactions initiated by the alkyl radical. From the viewpoint of exhibiting even better mechanical properties, the alkyl radical scavenger preferably includes 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 alkyl radical scavengers may be used in combination.

[0024] (Acrylphenol Compound) The acrylic phenol compound used in this embodiment can be represented by, for example, the following general formula (I).

[0025]

[0026] 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.

[0027] 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. Commercially available alkyl radical scavengers may be used, and examples of the acrylic phenol compound represented by general formula (I) include those available under the trade names "Sumilizer (registered trademark) GS" and "Sumilizer (registered trademark) GM" manufactured by Sumitomo Chemical Co., Ltd.

[0028] (Benzofuranone Compound) The benzofuranone compound used in this embodiment can be represented by, for example, the following general formula (II).

[0029]

[0030] 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 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.

[0031] 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, 5,7-di(t-butyl)-3-(3,4-di-propyl-phenyl)-3H-benzofuran-2-one, etc. Commercially available alkyl radical scavengers may be used, and examples of the benzofuranone compound represented by general formula (II) include "Irganox (registered trademark) HP-136" manufactured by BASF Japan Ltd. and "Revonox (registered trademark) 501" manufactured by Chitec Corporation.

[0032] (Alkyl Radical Scavenger Content) The content of the alkyl radical scavenger in the resin composition relative to 100 parts by mass of the 3-methyl-1-butene polymer is preferably 0.01 to 1.00 parts by mass. The content ratio of the alkyl radical scavenger in the insulating film is the same as above. When the alkyl radical scavenger content is 0.01 parts by mass or more, the physical properties of the resin composition can be more stably maintained during melt-kneading of the resin composition. Furthermore, generation of decomposition gas during melt molding, which results in molding defects, can be suppressed. Furthermore, when the alkyl radical scavenger content is 1.00 parts by mass or less, an insulating film with more excellent mechanical properties can be easily obtained. Furthermore, impairment of the physical properties required of the resin composition, such as bleeding out of the alkyl radical scavenger or deterioration of moisture absorption, can be suppressed.

[0033] From the viewpoint of maintaining the physical properties of the resin composition more stably during melt-kneading, the content of the alkyl radical scavenger in the resin composition relative to 100 parts by mass of the 3-methyl-1-butene polymer is more preferably 0.02 parts by mass or more, and even more preferably 0.05 parts by mass or more. Furthermore, from the viewpoint of a balance between maintaining the stability of the physical properties of the resin composition and economic efficiency, and from the viewpoint of obtaining an insulating film having a lower relative dielectric constant and a lower dielectric loss tangent, the content of the alkyl radical scavenger in the resin composition relative to 100 parts by mass of the 3-methyl-1-butene polymer is more preferably 0.80 parts by mass or less, and even more preferably 0.70 parts by mass or less. From these viewpoints, the content of the alkyl radical scavenger in the resin composition relative to 100 parts by mass of the 3-methyl-1-butene polymer is more preferably 0.02 to 0.80 parts by mass, and even more preferably 0.05 to 0.70 parts by mass. When two or more alkyl radical scavengers are contained, the content of the alkyl radical scavengers refers to the total content of the alkyl radical scavengers.

[0034] <Antioxidant> The resin composition may contain an antioxidant from the viewpoint of ensuring the stability of the polymer. The antioxidant preferably contains 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.

[0035] (Phenol-Based Antioxidant) Examples of the phenol-based antioxidant 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-butyl Resole, 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-m-cresol, octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)-propionate, and 3,5-bis-(1,1-dimethylethyl)-4-hydroxy-C benzenepropanoate ７ -C ９ Branched alkyl esters and the like are included.

[0036] 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.

[0037] (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)octyl phosphite, tris(2,4-di-t-butylphenyl)phosphite, 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]phosphonate, 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-C １２ -C １５ -alkyl(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.

[0038] 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.

[0039] (Sulfur-Based Antioxidants) Examples of sulfur-based antioxidants include dilauryl 3,3′-thiodipropionate, dimyristyl 3,3′-thiodipropionate, distearyl 3,3′-thiodipropionate, laurylstearyl 3,3′-thiodipropionate, pentaerythritol-tetrakis-(β-lauryl-thio-propionate), 3,9-bis(2-dodecylthioethyl)-2,4,8,10-tetraoxaspiro[5,5]undecane, and the like.

[0040] (Other Antioxidants) The resin composition may contain other antioxidants besides the phenol-based antioxidants, phosphorus-based antioxidants, and sulfur-based antioxidants, as long as the effects of the present invention are not impaired. Examples of antioxidants other than the phenol-based antioxidants, phosphorus-based antioxidants, and sulfur-based antioxidants include amine-based antioxidants.

[0041] (Antioxidant Content) The content of the antioxidant in the resin composition relative to 100 parts by mass of the 3-methyl-1-butene polymer is preferably 0.01 parts by mass or more, more preferably 0.10 parts by mass or more, from the viewpoint of ensuring the stability of the 3-methyl-1-butene polymer, and is preferably 1.00 parts by mass or less, more preferably 0.80 parts by mass or less, from the viewpoint of the relative dielectric constant and the dielectric loss tangent. That is, it is preferably 0.01 to 1.00 parts by mass, more preferably 0.10 to 0.80 parts by mass. The content ratio of the antioxidant in the insulating film is the same as above. Note that when the resin composition contains two or more antioxidants, the content of the antioxidants refers to the total content of the antioxidants.

[0042] <Other Additives> The resin composition may contain additives other than the alkyl radical scavenger and the antioxidant. Examples of the 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 of the other additives may be used alone, or two or more may be used in combination.

[0043] (Antacid Agent) From the viewpoint of suppressing deterioration due to acid components generated from residual metals and the like during melt-kneading, the resin composition preferably contains an antacid. Examples of antacid agents 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.

[0044] The content of the antacid in the resin composition relative to 100 parts by mass of the 3-methyl-1-butene polymer can be determined appropriately and may be, for example, 0.01 to 200 parts by mass, 0.01 to 0.5 parts by mass, or 0.01 to 0.3 parts by mass. The content of the antacid in the insulating film is the same as above.

[0045] (Antistatic Agent) Examples of the antistatic agent include sodium alkylsulfonate, phosphonium alkylsulfonate, and fatty acid ester hydroxyamine compounds, which are glycerin esters of stearic acid.

[0046] The content of the antistatic agent in the resin composition relative to 100 parts by mass of the 3-methyl-1-butene polymer can be appropriately determined and may be, for example, 5 parts by mass or less. The content of the antistatic agent in the insulating film is the same as above.

[0047] (Filler) The resin composition may contain a filler from the viewpoint of further improving the mechanical properties of the insulating film. Examples of fillers 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. Among these, glass fiber is preferred from the viewpoint of further improving the mechanical properties of the insulating film. One filler may be used alone, or two or more fillers may be used in combination.

[0048] The content of the filler in the resin composition relative to 100 parts by mass of the 3-methyl-1-butene polymer can be appropriately determined and may be, for example, 0.01 to 300 parts by mass or 0.1 to 100 parts by mass. The content of the filler in the insulating film is the same as above.

[0049] (Ultraviolet Absorber) Examples of the ultraviolet absorber include hindered amine ultraviolet absorbers such as 2,2,6,6-tetramethyl-4-piperidyl benzoate, bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)-2-(3,5-di-t-butyl-4-hydroxybenzyl)-2-n-butylmalonate, and 4-(3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxy)-1-(2-(3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxy)ethyl)-2,2,6,6-tetramethylpiperidine; Benzotriazole-based ultraviolet absorbers such as 2-(2-hydroxy-5-methylphenyl)benzotriazole, 2-(3-t-butyl-2-hydroxy-5-methylphenyl)-5-chlorobenzotriazole, 2-(3,5-di-t-butyl-2-hydroxyphenyl)-5-chlorobenzotriazole, and 2-(3,5-di-t-amyl-2-hydroxyphenyl)benzotriazole; and benzoate-based ultraviolet absorbers such as 2,4-di-t-butylphenyl-3,5-di-t-butyl-4-hydroxybenzoate and hexadecyl-3,5-di-t-butyl-4-hydroxybenzoate.

[0050] The content of the ultraviolet absorber in the resin composition relative to 100 parts by mass of the 3-methyl-1-butene polymer can be appropriately determined and may be, for example, 0.001 to 5 parts by mass or 0.01 to 1 part by mass. The content of the ultraviolet absorber in the insulating film is the same as above.

[0051] (Lubricant) Inorganic fine particles are generally used as the lubricant. Examples of the inorganic fine particles include particles of oxides, hydroxides, sulfides, nitrides, halides, carbonates, sulfates, acetates, phosphates, phosphites, organic carboxylates, silicates, titanates, borates, and hydrated compounds thereof, composite compounds mainly composed of these, and natural minerals, of elements of Groups 1, 2, 4, 6, 7, 8 to 10, 11, 12, 13, and 14 of the periodic table.

[0052] Examples of inorganic fine particles include Group 1 element compounds such as lithium fluoride and borax (sodium borate hydrate); Group 2 element compounds such as magnesium carbonate, magnesium phosphate, magnesium oxide (magnesiu), magnesium chloride, magnesium acetate, magnesium fluoride, magnesium titanate, magnesium silicate, magnesium silicate hydrate (talc), calcium carbonate, calcium phosphate, calcium phosphite, calcium sulfate (gypsum), calcium acetate, calcium terephthalate, calcium hydroxide, calcium silicate, calcium fluoride, calcium titanate, strontium titanate, barium titanate, zinc titanate, lanthanum titanate, bismuth titanate, lead titanate, barium carbonate, barium phosphate, barium sulfate, and barium phosphite; titanium dioxide (titania Group 4 element compounds such as titanium monoxide, titanium nitride, zirconium dioxide (zirconia), and zirconium monoxide; Group 6 element compounds such as molybdenum dioxide, molybdenum trioxide, and molybdenum sulfide; Group 7 element compounds such as manganese chloride and manganese acetate; Group 8 to 10 element compounds such as cobalt chloride and cobalt acetate; Group 11 element compounds such as cuprous iodide; Group 12 element compounds such as zinc oxide and zinc acetate; Group 13 element compounds such as aluminum oxide (alumina), aluminum hydroxide, aluminum fluoride, and aluminosilicates (alumina silicate, kaolin, and kaolinite); Group 14 element compounds such as silicon oxide (silica, silica gel), graphite, carbon, graphite, and glass; and fine particles of natural minerals such as karnalite, kainite, mica, and byrrosite. There are no particular limitations on the average particle size of the inorganic fine particles, but it is preferably 0.01 to 3 μm.

[0053] The content of the lubricant in the resin composition relative to 100 parts by mass of the 3-methyl-1-butene polymer can be appropriately determined and may be, for example, 0.001 to 5 parts by mass or 0.005 to 3 parts by mass. The content of the lubricant in the insulating film is the same as above.

[0054] <Other Resins> The resin composition may or may not contain a resin other than the 3-methyl-1-butene polymer. In order to improve the dispersibility of additives containing polar groups, the resin composition may contain other resins other than the 3-methyl-1-butene polymer, such as a vinyl acetate-ethylene copolymer or a modified polyolefin obtained by partially oxidizing a polyolefin and / or modifying it with a reactive functional group such as maleic acid. Examples of polyolefins constituting the modified polyolefin modified with a reactive functional group include polyethylene, polypropylene, and polyolefins having a structural unit of an α-olefin having 3 to 20 carbon atoms. Examples of α-olefins having 3 to 20 carbon atoms include those described above in the <3-methyl-1-butene polymer> section. These may be homopolymers or copolymers. Furthermore, these polyolefins may be high-density or low-density and may be polymerized using at least one catalyst selected from the group consisting of a Ziegler-Natta catalyst and a metallocene catalyst. Among these, the resin other than the 3-methyl-1-butene polymer is preferably at least one selected from the group consisting of polyethylene or polypropylene, more preferably at least one selected from the group consisting of modified polyethylene or modified polypropylene, more preferably at least one selected from the group consisting of modified polyethylene or modified polypropylene in which polyolefin is partially oxidized and / or modified with a reactive functional group such as maleic acid, and even more preferably maleic anhydride-modified polypropylene.

[0055] From the viewpoint of further exerting the effects of the present invention, the content of the vinyl acetate-ethylene copolymer and the modified polyolefin obtained by partially oxidizing a polyolefin and / or modifying a polyolefin with a reactive functional group such as maleic acid in the resin composition is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 10 parts by mass or less, relative to 100 parts by mass of the 3-methyl-1-butene polymer.

[0056] Examples of resins other than vinyl acetate-ethylene copolymers and modified polyolefins in which polyolefins are partially oxidized and / or modified with reactive functional groups such as maleic acid include polyolefins such as low-density polyethylene, high-density polyethylene, linear low-density polyethylene, very low-density polyethylene, polypropylene, syndiotactic polypropylene, polybutene, and polypentene; polyesters such as polyethylene terephthalate and polybutylene terephthalate; polyamides such as nylon 6 and nylon 66; ethylene-ethyl acrylate copolymers, polystyrene, syndiotactic polystyrene, polyphenylene sulfide, polyphenylene ether, polycarbonate, and thermoplastic elastomers. Examples of thermoplastic elastomers include random or block copolymers of aromatic vinyl monomers and conjugated diene monomers, such as styrene-butadiene block copolymers, styrene-butadiene-styrene block copolymers, styrene-isoprene block copolymers, styrene-isoprene-styrene block copolymers, and styrene-butadiene random copolymers; polyisoprene rubber; polyolefin rubbers, such as ethylene-propylene copolymers, ethylene-α-olefin copolymers, and propylene-α-olefin copolymers; diene copolymers, such as ethylene-propylene-diene copolymers, α-olefin-diene copolymers, diene copolymers, isobutylene-isoprene copolymers, and isobutylene-diene copolymers; norbornene rubbery polymers, such as copolymers of norbornene monomers and ethylene or α-olefins, terpolymers of norbornene monomers, ethylene and α-olefins, and ring-opening polymers of norbornene monomers, and hydrogenated versions of these.

[0057] In order to further improve the flexibility, bendability, and impact resistance of the insulating film, the resin composition may contain a thermoplastic elastomer. When the resin composition contains a thermoplastic elastomer, the insulating film is less susceptible to distortion and impact, and cracking can be suppressed.

[0058] From the viewpoint of impact resistance, the thermoplastic elastomer preferably has a glass transition temperature (Tg) of 40°C or lower. Some block copolymers have two or more Tg points, but they can be preferably used as long as one of the Tg points is 40°C or lower. The number-average molecular weight of the thermoplastic elastomer is preferably 10,000 or higher, more preferably 20,000 or higher, even more preferably 30,000 or higher, and preferably 200,000 or lower. A number-average molecular weight of 10,000 or higher provides superior mechanical properties, while a number-average molecular weight of 200,000 or lower facilitates production. From the viewpoint of compatibility with the 3-methyl-1-butene polymer, the thermoplastic elastomer is preferably non-polar, i.e., composed only of carbon and hydrogen.

[0059] From the viewpoint of obtaining an insulating film having a low relative dielectric constant and a low dielectric loss tangent, it is preferable that the resin composition has a reduced amount of metal elements. Therefore, from the viewpoint of easily reducing the amount of metal elements, the thermoplastic elastomer is preferably a copolymer of an aromatic vinyl monomer and a conjugated diene monomer, and more preferably a block copolymer thereof. Furthermore, from the viewpoint of improving weather resistance, a hydrogenated product thereof is even more preferable.

[0060] The content of the other resins other than the thermoplastic elastomer, vinyl acetate-ethylene copolymer, and modified polyolefin obtained by partially oxidizing polyolefin and / or modifying with a reactive functional group such as maleic acid in the resin composition is preferably 1 to 100 parts by mass, more preferably 2 to 50 parts by mass, and even more preferably 3 to 30 parts by mass, per 100 parts by mass of the 3-methyl-1-butene polymer. The content of the other resins other than the thermoplastic elastomer, vinyl acetate-ethylene copolymer, and modified polyolefin obtained by partially oxidizing polyolefin and / or modifying with a reactive functional group such as maleic acid in the insulating film is also the same as above. Within the above range, the excellent physical properties of the 3-methyl-1-butene polymer, such as heat resistance and chemical resistance, are likely to be exhibited.

[0061] <Melting Point of Resin Composition> The melting point of the resin composition of this embodiment is preferably 260 to 310°C. When the melting point of the resin composition is within the above range, molding can be facilitated and reflow heat resistance can be further improved. The melting point of the resin composition refers to the peak temperature when measured using a method similar to that used to measure the melting point of a 3-methyl-1-butene polymer. Specifically, it can be measured using the method for measuring the melting point of a 3-methyl-1-butene polymer described in the Examples. From the viewpoint of a balance between processability and heat resistance, the melting point of the resin composition is preferably 270 to 305°C, more preferably 280 to 305°C, and even more preferably 280 to 300°C. The melting point of the resin composition of this embodiment is almost the same as that of the 3-methyl-1-butene polymer. Therefore, in this specification, the melting point of the 3-methyl-1-butene polymer can be considered to be the melting point of the resin composition.

[0062] <Method for Producing Resin Composition> The method for producing the resin composition of this embodiment is not particularly limited as long as it can produce a resin composition containing a 3-methyl-1-butene polymer. More specifically, the method for producing the resin composition includes a step of obtaining a 3-methyl-1-butene polymer and a step of obtaining a resin composition. Details of each step can be found in the sections [Step of Obtaining a 3-methyl-1-butene Polymer] and [Step of Obtaining a Resin Composition] described below.

[0063] [Insulating Film] The insulating film of the present embodiment contains the resin composition of the present embodiment. The insulating film of the present embodiment contains a 3-methyl-1-butene polymer. The insulating film of the present embodiment may consist of only the resin composition, or may contain components other than the resin composition.

[0064] <Dielectric Loss Tangent> The dielectric loss tangent of the insulating film of this embodiment refers to the dielectric loss tangent measured at a specific frequency, specifically, at a frequency of 10 GHz to 300 GHz. The dielectric loss tangent of the insulating film of this embodiment at a frequency of 10 GHz to 300 GHz is less than 0.00070. If the dielectric loss tangent is 0.00070 or more, the millimeter-wave antenna will experience increased transmission loss when used in the millimeter wave band, potentially impairing its practical use as a millimeter-wave antenna. From the viewpoint of further reducing transmission loss, the dielectric loss tangent is preferably 0.00060 or less, more preferably 0.00055 or less, and even more preferably 0.00050 or less. The dielectric loss tangent is preferably 0.00010 or more, more preferably 0.00013 or more, and even more preferably 0.00015 or more. That is, the dielectric loss tangent of the insulating film at a frequency of 10 GHz to 300 GHz is preferably 0.00010 to 0.00060, more preferably 0.00013 to 0.00055, and even more preferably 0.00015 to 0.00050. The dielectric loss tangent of the insulating film at a frequency of 10 GHz to 300 GHz refers to a value measured by a common method such as a capacitance method, a resonance method, or a frequency variation method, and can be measured specifically by the method described in the Examples. When the frequency is 10 GHz or higher and 50 GHz or lower, measurement by the resonance method is preferred. When the frequency is higher than 50 GHz and lower than 300 GHz, measurement by the frequency variation method is preferred. In one aspect, the insulating film of this embodiment has a dielectric loss tangent at a frequency of 10 GHz measured by a resonance method of 0.00010 to 0.00060, preferably 0.00013 to 0.00055, and more preferably 0.00015 to 0.00050. In one aspect, the insulating film of the present embodiment has a dielectric loss tangent of 0.00010 to 0.00060, preferably 0.00013 to 0.00055, and more preferably 0.00015 to 0.00050 at a frequency of 100 GHz, as measured by a frequency variation method. In another aspect, the insulating film of the present embodiment has a dielectric loss tangent of 0.00010 to 0.00060, preferably 0.00013 to 0.00055, and more preferably 0.00015 to 0.00050 at a frequency of 200 GHz, as measured by a frequency variation method.

[0065] <Relative Dielectric Constant> The dielectric loss tangent of the insulating film of this embodiment refers to the relative dielectric constant measured at a specific frequency, specifically, the relative dielectric constant measured at a frequency of 10 GHz to 300 GHz. From the viewpoint of economy, the relative dielectric constant of the insulating film of this embodiment at frequencies of 10 GHz to 300 GHz is preferably 0.5 or more, more preferably 1.5 or more, and even more preferably 2.0 or more. From the viewpoint of reducing transmission loss, the relative dielectric constant is preferably 5.0 or less, more preferably 4.0 or less, more preferably 3.8 or less, and even more preferably 3.5 or less. That is, the relative dielectric constant of the insulating film at frequencies of 10 GHz to 300 GHz is preferably 0.5 to 5.0, more preferably 1.5 to 4.0, and even more preferably 2.0 to 3.5. The relative dielectric constant of the insulating film at frequencies of 10 GHz to 300 GHz refers to a value measured by a common method such as a capacitance method, a resonance method, or a frequency variation method. Specifically, it can be measured by the method described in the examples. When the measurement wavelength is 10 GHz or more and 50 GHz or less, measurement is preferably performed by a resonance method. When the measurement frequency is more than 50 GHz and 300 GHz or less, measurement is preferably performed by a frequency variation method. In one aspect, the insulating film of this embodiment has a relative dielectric constant at 10 GHz measured by a resonance method of 0.5 to 5.0, preferably 1.5 to 4.0, and more preferably 2.0 to 3.5. In one aspect, the insulating film of this embodiment has a relative dielectric constant at 100 GHz measured by a frequency variation method of 0.5 to 5.0, preferably 1.5 to 4.0, and more preferably 2.0 to 3.5. In one aspect, the insulating film of this embodiment has a relative dielectric constant at 200 GHz measured by a frequency variation method of 0.5 to 5.0, preferably 1.5 to 4.0, and more preferably 2.0 to 3.5.

[0066] <Water Absorption Rate> The water absorption rate of the insulating film of this embodiment is preferably 0.5% by mass or less, more preferably 0.3% by mass or less, and even more preferably 0.1% by mass or less. If the water absorption rate of the insulating film is within the above range, the occurrence of blisters during reflow soldering can be further suppressed. In addition, storage management before reflow soldering is also facilitated. The water absorption rate of the insulating film refers to a value measured in accordance with JIS K 7209:2000 Method A, and specifically can be measured by the method described in the examples.

[0067] <Method for Producing Insulating Film> The method for producing the insulating film of this embodiment can be a known method and is not particularly limited. The method for producing the insulating film of this embodiment preferably includes a step of obtaining a 3-methyl-1-butene polymer and a step of obtaining an insulating film. Furthermore, when a resin composition is obtained by blending other components such as an alkyl radical scavenger, an antioxidant, and other additives in addition to the 3-methyl-1-butene polymer, it is preferable to go through the step of obtaining a resin composition described below.

[0068] [Step of Obtaining a 3-methyl-1-butene Polymer] In this embodiment, the step of obtaining a 3-methyl-1-butene polymer is not particularly limited as long as it is a step that allows the production of a 3-methyl-1-butene polymer. The method of obtaining a 3-methyl-1-butene polymer is not particularly limited, and the polymer can be produced using a known catalyst such as a Ziegler-Natta catalyst or a metallocene catalyst. More specifically, the step of obtaining a 3-methyl-1-butene polymer is a step of preparing a raw material containing 3-methyl-1-butene and polymerizing this raw material to obtain a 3-methyl-1-butene polymer. A method of obtaining a 3-methyl-1-butene polymer, for example, as described in JP-A-61-103910, involves homopolymerizing 3-methyl-1-butene in the presence of a catalyst, or copolymerizing 3-methyl-1-butene with ethylene or one of the above-mentioned α-olefins, thereby obtaining a powder. In the case of homopolymerization, the raw material contains at least 3-methyl-1-butene and may further contain a catalyst. In the case of copolymerization, the raw materials contain at least 3-methyl-1-butene and ethylene or the above-mentioned α-olefin, and may further contain a catalyst. The stereoregularity of the 3-methyl-1-butene polymer may be isotactic or syndiotactic.

[0069] [Step of Obtaining Resin Composition] The step of obtaining a resin composition is a step of blending and mixing a 3-methyl-1-butene polymer and other components to obtain a resin composition. Specifically, this is a step of obtaining a resin composition containing a 3-methyl-1-butene polymer and other components. The resin composition is obtained by mixing the 3-methyl-1-butene polymer and other components. The mixing method is not particularly limited, and a method of melt-kneading using a twin-screw kneading extruder can be used. Furthermore, the raw materials may be dry-blended before melt-kneading. Note that if no components other than the 3-methyl-1-butene polymer are blended, the step of obtaining a resin composition is not necessary. Examples of other components include those described in the above [Resin Composition], such as alkyl radical scavengers, antioxidants, 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 lubrication agents.

[0070] <Melt-Kneading Conditions> The melt-kneading conditions are not particularly limited as long as they do not impair the effects of the present invention. However, it is preferable to perform melt-kneading in an oxygen-lower state than the atmosphere. It is more preferable to perform melt-kneading by injecting an inert gas into the melt-kneader or by degassing the inside of the melt-kneader under reduced pressure. In order to suppress deterioration of the physical properties of the resin composition due to oxygen and produce an insulating film with even better dielectric and mechanical properties, it is preferable to perform melt-kneading in an inert atmosphere or a low-oxygen state. Here, in this embodiment, the "low-oxygen state" refers to a state in which the oxygen concentration is lowered by degassing the inside of the melt-kneader under reduced pressure compared to before degassing. Alternatively, it refers to a state in which the oxygen concentration is lowered by injecting an inert gas such as nitrogen gas compared to before the injection. 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 is measured using an oxygen concentration meter such as a diaphragm-type galvanic oxygen meter.

[0071] The method of melt-kneading by injecting an inert gas into the melt kneader may involve, for example, introducing each component into the melt kneader while injecting the inert gas, or introducing each component into the melt kneader and then injecting the inert gas to perform melt kneading. Furthermore, the inert gas may be continuously injected into the melt kneader during melt kneading. The inert gas may be injected according to the equipment of each melt kneader. For example, the inert gas may be injected from a gas supply section 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. There are no limitations on the injection method as long as the inert gas can be injected into the entire area from the inert gas supply section to the heating section where melt kneading is performed, thereby enabling melt kneading. Examples of inert gases include nitrogen gas, helium gas, neon gas, argon gas, krypton gas, and carbon dioxide gas. Nitrogen gas is preferred from the viewpoints of availability and versatility.

[0072] The method of degassing the inside of the melt kneader under reduced pressure to melt and knead may be, for example, to add each component to the inside of the melt kneader, and then degas the inside of the melt kneader under reduced pressure to perform melt kneading. Moreover, during melt kneading, degassing the inside of the melt kneader under reduced pressure may be performed intermittently or continuously. The method of degassing the inside of the melt kneader under reduced pressure can be performed depending on the equipment provided in each melt kneader, and may be performed, for example, through a vacuum vent. When degassing under reduced pressure, the inside of the melt kneader can be placed in a vacuum state of, for example, 0.1 kPa or more and 50 kPa or less.

[0073] 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 inside of the melt kneader, or equipment capable of melt-kneading by degassing the inside of the melt kneader under reduced pressure.

[0074] The melt-kneading temperature is preferably 300 to 380°C. When the melt-kneading temperature is 300°C or higher, the 3-methyl-1-butene polymer can be sufficiently melted, and additives and the like can be easily dispersed. When the melt-kneading temperature is 380°C or lower, thermal decomposition of the 3-methyl-1-butene polymer and additives can be suppressed. From the viewpoint of sufficiently dispersing the additives throughout the 3-methyl-1-butene polymer, the melt-kneading temperature is more preferably 300°C or higher, and even more preferably 310°C or higher. Furthermore, from the viewpoint of suppressing significant decomposition of the raw materials, the melt-kneading temperature is more preferably 380°C or lower, and even more preferably 360°C or lower.

[0075] The melt-kneading time can be adjusted depending on the size of the kneading apparatus, etc. For example, it may be 1 to 15 minutes, but is not limited to this numerical range of the melt-kneading time. In this embodiment, the "melt-kneading time" refers to the time during which the mixer is rotating in a batch-type kneader, and refers to the residence time of the raw materials in the apparatus in the case of a continuous extrusion-type kneader.

[0076] The rotation speed of the mixer during melt-kneading may be 80 rpm or more or 100 rpm or more, and may be 300 rpm or less or 250 rpm or less. After melt-kneading, the resin composition is removed from the melt-kneader and cooled.

[0077] [Step of Obtaining an Insulating Film] In this embodiment, the step of obtaining an insulating film is a step of obtaining an insulating film by molding a material used for the insulating film. Methods for molding the insulating film from the material include, for example, extrusion molding and heat press molding. In this embodiment, the insulating film can be used as a millimeter-wave antenna substrate. When using the insulating film as a millimeter-wave antenna substrate, the shape of the millimeter-wave antenna substrate is selected according to the components used in the millimeter-wave antenna, the performance, etc. The thickness of the millimeter-wave antenna substrate may be, for example, 0.01 to 5 mm.

[0078] <Copper-Clad Laminate and Millimeter-Wave Antenna> In this embodiment, when the insulating film is used as a millimeter-wave antenna substrate, the insulating film preferably includes a conductive layer on its surface. That is, in this embodiment, the insulating film can be used as a millimeter-wave antenna including an insulating film and a conductive layer. The conductive layer functions as an electrode. The conductive layer includes a conductive material. The conductive material may be any conductive material, for example, a metal material or a carbon-based conductive material. Examples of the metal material include metal materials such as copper, silver, gold, and aluminum, or alloys using these metal materials. In this embodiment, the method for forming the conductive layer on the insulating film is not particularly limited, and examples include plating, printing, sputtering, and vapor deposition. In this embodiment, the conductive layer can also be formed using a metal foil. Specifically, the insulating film can have a metal foil on its surface. The metal foil can be any of the above-mentioned metal materials, and metal foils including copper, silver, gold, and aluminum can be used. In this embodiment, copper foil is preferably used from the viewpoint of conductivity. That is, in this embodiment, it is preferable to have an insulating film and copper foil, and a copper-clad laminate in which copper foil is laminated on the surface of an insulating film is more preferable.

[0079] The copper-clad laminate of this embodiment includes the insulating film. Because the insulating film has excellent dielectric properties and other characteristics as described above, the copper-clad laminate can be used, for example, in millimeter-wave antennas, semiconductor substrates, base station substrates, and the like. In particular, the copper-clad laminate is suitable for use in millimeter-wave antennas. Therefore, the millimeter-wave antenna of this embodiment includes the copper-clad laminate. The copper-clad laminate preferably includes copper foil on the surface of the insulating film. Specifically, the copper-clad laminate can include copper foil on at least one or both sides of the insulating film. Furthermore, the number of copper foils and insulating films in the copper-clad laminate is not particularly limited. When the copper-clad laminate is used in a millimeter-wave antenna, the insulating film included in the copper-clad laminate functions as a millimeter-wave antenna substrate, and the copper foil functions as an electrode.

[0080] The copper foil can be provided on the surface of the insulating film by any known method, such as etching, sputtering, or vacuum deposition. Alternatively, the copper foil may be laminated on one or both surfaces of the insulating film and then hot-pressed to produce a copper-clad laminate. The hot-pressing conditions are not particularly limited, and the pressing temperature may be 200 to 350°C, and the pressing pressure may be 50 to 150 f / cm. ２ may be.

[0081] The thickness of the copper foil provided on the surface of the insulating film may be, for example, 0.1 to 100 μm. Before providing the copper foil on the surface of the insulating film, the surface of the insulating film may be subjected to a pretreatment such as degreasing, plasma treatment, UV ozone treatment, or laser treatment. The treatment conditions for the pretreatment are not limited as long as they do not impair the effects of the present invention.

[0082] <Uses of Millimeter-Wave Antenna> The millimeter-wave antenna of this embodiment is an antenna that can be suitably used for frequencies of 30 GHz to 300 GHz (i.e., millimeter waves). However, the usable frequency is not limited to millimeter waves, as long as the effects of the present invention are not impaired. The millimeter-wave antenna of this embodiment includes an insulating film that has a low relative dielectric constant and a low dielectric loss tangent and excellent formability, and is unlikely to experience transmission loss even when used in the tens of GHz band. Furthermore, the millimeter-wave antenna of this embodiment has excellent reflow heat resistance. Therefore, the millimeter-wave antenna of this embodiment can be used for short-range wireless communications, on-board radar in automobiles, etc., mobile phones, PHS phones, smartphones, tablets (tablet computers), mobile computers (mobile PCs), personal digital assistants (PDAs), and the like.

[0083] The present invention will be specifically explained below with reference to examples and comparative examples, but the present invention is not limited to these.

[0084] <Measurement and Evaluation Methods> Various physical properties were measured or evaluated by the following methods.

[0085] [Content of structural units derived from comonomers] The content of structural units derived from 1-decene (comonomer), which is an α-olefin other than 3-methyl-1-butene, in the copolymers (3-methyl-1-butene polymers) obtained in Production Examples 1 and 2 was determined by IR measurement using an FT-IR analyzer (manufactured by Ailent Technologies, device name "Cary 600 series FTIR spectrometer") by the ATR method, as follows: －１ and the bending vibration of 727 cm originating from the side chain methylene group of the α-olefin homopolymer. －１ A calibration curve was created from the ratio of the peak area of ​​each polymer to the peak area of ​​the copolymer obtained in Production Examples 1 and 2. The IR measurement was performed on the copolymers obtained in Production Examples 1 and 2, and the obtained measured values ​​(peak area ratios) were inserted into the calibration curve to determine the content of structural units derived from α-olefins other than 3-methyl-1-butene (1-decene).

[0086] [Melting Point] Using a differential scanning calorimeter ("DSC25" manufactured by TA Instruments) the copolymers or homopolymers (3-methyl-1-butene polymers) obtained in Production Examples 1 to 3 were heated from 30°C to 320°C at a rate of 10°C / min under a 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. After holding at -70°C for 5 minutes, the temperature was increased to 320°C at a rate of 10°C / min, and the peak temperature of the endothermic peak accompanying melting was measured, and this temperature was taken as the melting point.

[0087] [Melt Viscosity] The melt viscosity (Pa s) of the copolymers or homopolymers (3-methyl-1-butene polymers) obtained in Production Examples 1 to 3 was measured using a capillary rheometer ("Capillography 1C" manufactured by Toyo Seiki Seisaku-sho, Ltd.) at a barrel temperature of 320°C and a shear rate of 1220 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).

[0088] [Melt moldability] Whether or not an insulating film (length: 1000 mm, width: 80 mm, thickness: 0.5 mm) could be produced by extrusion molding was evaluated. The resin compositions obtained in Examples 1 to 4, the resin composition obtained in Comparative Example 1, and the resin of Comparative Example 3 were extrusion molded under the conditions described below in Examples 1 to 4 and Comparative Examples 1 and 3, respectively. The resin of Comparative Example 2 was extrusion molded under the same conditions as in Example 1, except that the cylinder temperature was set to 380°C. If the insulating film could be molded, it was given an "A", and if not, it was given a "B".

[0089] [Mechanical Strength] Test specimens (length: 150 mm, width: 25 mm, thickness: 0.5 mm) were prepared by cutting out the insulating films used in Examples 1 to 4 and Comparative Example 1. The test specimens were stored at 23°C and 49% humidity for 24 hours or more, and the yield stress (MPa) was measured at 23°C, 49% humidity, and a tensile speed of 100 mm / min using a universal material testing machine "INSTRON 5900R-5666" (manufactured by Instron Corporation) in accordance with JIS K 7161-1:2014. The measurement was performed five times, and the average value was used. A yield stress of 27 MPa or more was rated "A," and a yield stress of less than 27 MPa was rated "B."

[0090] [Specific Gravity] Test pieces (length: 60 mm, width: 60 mm, thickness: 0.5 mm) were prepared by cutting out the insulating films used in Examples 1 to 4 and Comparative Examples 1 to 3. Using the test pieces, specific gravity was measured in accordance with Method A of JIS K 7112:1999.

[0091] [Water Absorption Rate] Test pieces (length: 60 mm, width: 60 mm, thickness: 0.5 mm) were prepared by cutting out the insulating films used in Examples 1 to 4 and Comparative Examples 1 to 3. The water absorption rate was measured using the test pieces in accordance with Method A of JIS K 7209:2000.

[0092] [Dielectric Constant and Dielectric Loss Tangent] The insulating films used in Examples 1 to 4 and Comparative Examples 1 to 3 were cut out to prepare test specimens (length: 40 mm, width: 40 mm, thickness: 0.5 mm). Using the test specimens, the dielectric constant and dielectric loss tangent at a measurement frequency of 10 GHz were measured by a perturbation cavity resonance method using a vector network analyzer "Keysight E8361A" (manufactured by Agilent Technologies). Furthermore, the insulating films used in Examples 1 to 4 and Comparative Example 1 were cut out to prepare test specimens (length: 40 mm, width: 40 mm, thickness: 0.5 mm). Using the test specimens, the dielectric constant and dielectric loss tangent at a measurement frequency of 100 GHz were measured by a frequency variation method using a millimeter-wave module (manufactured by Virginia Diodes Inc., WR10 67 GHz-115 GHz). Test pieces (length: 40 mm, width: 40 mm, thickness: 0.5 mm) were prepared by cutting out the insulating films used in Examples 1 to 4 and Comparative Example 1. Using the test pieces, the relative permittivity and dielectric loss tangent were measured at a measurement frequency of 200 GHz by a frequency variation method using a vector network analyzer (Anritsu ME7838G 70 kHz-220 GHz).

[0093] [Reflow Heat Resistance] The millimeter-wave antennas obtained in Examples 1 to 4 and Comparative Examples 1 to 3 were left to stand for 7 days in an atmosphere of 85°C and 85% RH. After standing, the millimeter-wave antennas were heat-treated using a high-temperature observation device "SMT Scope Light SL-1" (manufactured by Sanyo Seiko Co., Ltd.) according to the following reflow temperature profile, and the appearance of the millimeter-wave antenna was observed and evaluated. Specifically, a sample in which at least one of warping, melting, and blisters was observed was rated "B," and a sample in which none of the following was observed was rated "A." Reflow temperature profile: The temperature was raised from 25°C to 150°C over 60 seconds, then raised to 180°C over 80 seconds, and further raised to 280°C over 60 seconds, and held at 280°C for 10 seconds. Air cooling was then performed.

[0094] [Catalyst Preparation] 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 at 130°C for 2 hours to form 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. After the dropwise addition was completed, the temperature of the mixture was raised to 90°C over 2 hours. Upon reaching 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 the 2-hour reaction, the mixture was allowed to stand and the supernatant was removed. Decane and hexane were added, and the solid component was washed three times. After that, it was resuspended in 2 L of titanium tetrachloride and again heated 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% by mass of titanium, 56.0% by mass of chlorine, 17.0% by mass of magnesium, 10.4% by mass of ethyl benzoate, and 12.6% by mass of a hydrocarbon solvent consisting of decane and hexane.

[0095] [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 produced 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 fed 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. This crude polymer 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 104 Pa s. Furthermore, the content of structural units derived from the comonomer 1-decene in copolymer (A) was 1.1 mol%.

[0096] [Production Example 2] Production of Copolymer (B) The same procedure as in Production Example 1 was carried out, except that 0.6 kg of 1-decene was changed to 3.6 kg of 1-decene, to obtain 2.8 kg of copolymer (B), a copolymer of 3-methyl-1-butene and 1-decene. When the above-mentioned measurements were carried out on the obtained copolymer (B), it was found that the melting point was 281°C and the melt viscosity was 99 Pa s. Furthermore, the content of structural units derived from the comonomer 1-decene in copolymer (B) was 6.4 mol%.

[0097] [Production Example 3] Production of homopolymer (C) The same operation as in Production Example 1 was carried out, except that 0.6 kg of 1-decene was not added, to obtain 3.3 kg of homopolymer (C), which is a homopolymer of 3-methyl-1-butene. When the above-mentioned measurements were carried out on the obtained homopolymer (C), it was found that the melting point was 305°C and the melt viscosity was 126 Pa s.

[0098] Example 1 (1) Production of Resin Composition 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] ("AO-60", manufactured by ADEKA Corporation) as a phenolic antioxidant, and 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 ("PEP-36", manufactured by ADEKA Corporation) as a phosphorus-based antioxidant were added. , 0.1 parts by mass of 2,4-di-t-amyl-6-[1-(3,5-di-t-amyl-2-hydroxyphenyl)ethyl]phenyl acrylate ("Sumilizer (registered trademark) GS", manufactured by Sumitomo Chemical Co., Ltd.) as an alkyl radical scavenger (acrylic phenol compound), and 0.25 parts by mass of zinc stearate (antacid) were dry-blended, and then the mixture was melt-kneaded under a nitrogen atmosphere using a twin-screw kneading extruder "KZW15-45" (manufactured by Technovel Corporation) to obtain a pellet-shaped resin composition (M1).

[0099] (2) Production of Millimeter-Wave Antenna The obtained pellet-shaped resin composition (M1) was melt-kneaded at a cylinder temperature of 310°C under a nitrogen atmosphere using a twin-screw kneading extruder "KZW15-45" (manufactured by Technovel Co., Ltd.), and melt-extruded into a film from a T-die. The obtained film was then cooled and solidified on a cooling roll at 110°C to obtain an insulating film with a thickness of 0.5 mm. After plasma treatment of the insulating film, copper foil with a thickness of 35 μm was laminated on both sides, and the resulting mixture was subjected to a pressure of 300°C and 70 kgf / cm. ２ The results of evaluation according to the above-mentioned evaluation methods are shown in Table 1.

[0100] Example 2 (1) Production of Resin Composition 100 parts by mass of the copolymer (A) obtained in Production Example 1 was dry-blended with 0.2 parts by mass of pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate] ("AO-60", manufactured by ADEKA Corporation) as a phenolic antioxidant, 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 ("PEP-36", manufactured by ADEKA Corporation) as a phosphorus-based antioxidant, and 0.25 parts by mass of zinc stearate (antacid), and the mixture was melt-kneaded under a nitrogen atmosphere using a twin-screw kneading extruder "KZW15-45" (manufactured by Technovel Corporation) to obtain a pellet-shaped resin composition (M2).

[0101] (2) Production of Millimeter-Wave Antenna The obtained pellet-shaped resin composition (M2) was melt-kneaded at a cylinder temperature of 310°C under a nitrogen atmosphere using a twin-screw kneading extruder "KZW15-45" (manufactured by Technovel Co., Ltd.), and melt-extruded into a film from a T-die. The obtained film was then cooled and solidified on a cooling roll at 110°C to obtain an insulating film with a thickness of 0.5 mm. After plasma treatment of the insulating film, copper foil with a thickness of 35 μm was laminated on both sides, and the resulting mixture was subjected to a pressure of 300°C and 70 kgf / cm. ２ The results of evaluation according to the above-mentioned evaluation methods are shown in Table 1.

[0102] Comparative Example 1 (1) Production of Resin Composition 100 parts by mass of the copolymer (A) obtained in Production Example 1 was dry-blended with 0.67 parts by mass of pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate] ("AO-60", manufactured by ADEKA Corporation) as a phenolic antioxidant, 1.33 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 ("PEP-36", manufactured by ADEKA Corporation) as a phosphorus-based antioxidant, and 0.25 parts by mass of zinc stearate (antacid), and the mixture was melt-kneaded under an air atmosphere using a twin-screw kneading extruder "KZW15-45" (manufactured by Technovel Corporation) to obtain a pellet-shaped resin composition (M3).

[0103] (2) Production of Millimeter-Wave Antenna The obtained pellet-shaped resin composition (M3) was melt-kneaded in an air atmosphere at a cylinder temperature of 310°C using a twin-screw kneading extruder "KZW15-45" (manufactured by Technovel Corporation), and melt-extruded into a film from a T-die. The obtained film was then cooled and solidified on a cooling roll at 110°C to obtain an insulating film with a thickness of 0.5 mm. After plasma treatment of the insulating film, copper foil with a thickness of 35 μm was laminated on both sides, and the resulting mixture was subjected to a pressure of 300°C and 70 kgf / cm. ２ The results of evaluation according to the above-mentioned evaluation methods are shown in Table 1.

[0104] [Example 3] A resin composition (M4), an insulating film, and a millimeter-wave antenna were produced in the same manner as in Example 1, except that the copolymer (B) obtained in Production Example 2 was used instead of the copolymer (A). The results of evaluation according to the above-mentioned evaluation methods are shown in Table 1.

[0105] [Example 4] A resin composition (M5), an insulating film, and a millimeter-wave antenna were produced in the same manner as in Example 1, except that the homopolymer (C) obtained in Production Example 3 was used instead of the copolymer (A). The results of evaluation according to the above-mentioned evaluation methods are shown in Table 1.

[0106]

[0107] Comparative Example 2 PTFE "Polyflon (registered trademark) M12" (manufactured by Daikin Industries, Ltd.) was placed in a compression molding die having a 100 mm square die and a die length of 500 mm, and compressed at room temperature under a molding pressure of 200 kgf / cm using a compression molding machine (manufactured by Shinto Metal Industries Co., Ltd., AYS10). ２ The insulating film was then subjected to a plasma treatment in the same manner as in Example 1, and then 35 μm thick copper foils were laminated on both sides of the insulating film. ２ The results of evaluation according to the above-mentioned evaluation methods are shown in Table 2.

[0108] Comparative Example 3 A sheet-shaped insulating film having a thickness of 0.5 mm was obtained in the same manner as in Example 1, except that polymethylpentene "TPX (registered trademark) MX0020" (manufactured by Mitsui Chemicals, Inc.) was used instead of the resin composition (M1), the cylinder temperature was set to 270°C, and cooling and solidifying were performed on a cooling roll at 80°C. After the insulating film was subjected to a plasma treatment in the same manner as in Example 1, copper foils having a thickness of 35 μm were laminated on both sides, and the film was subjected to a plasma treatment at 300°C and 70 kgf / cm. ２ The results of evaluation according to the above-mentioned evaluation methods are shown in Table 2.

[0109]

[0110] Table 1 shows that the insulating films of Examples 1 to 4 contain a material containing a 3-methyl-1-butene polymer, and have excellent dielectric properties, as evidenced by a dielectric dissipation factor of less than 0.00070 at frequencies between 10 GHz and 300 GHz. Furthermore, in Examples 1, 3, and 4, the material contains an alkyl radical scavenger, resulting in a mechanical strength of "A," indicating even better mechanical properties for the insulating films. On the other hand, the insulating film of Comparative Example 1 contains a material containing a 3-methyl-1-butene polymer, but has a dielectric dissipation factor of 0.00070 or greater at frequencies between 10 GHz and 300 GHz, resulting in inferior dielectric properties compared to Examples 1 to 4. It is believed that Comparative Example 1 required a large amount of antioxidant to prevent the material containing a 3-methyl-1-butene polymer from deteriorating due to oxygen, which prevented it from exhibiting excellent dielectric properties. As shown in Table 2, Comparative Example 2 achieved a melt moldability rating of "B," while Comparative Example 3 achieved a dielectric loss tangent of 0.00070 or more and a reflow heat resistance rating of "B." Therefore, Comparative Examples 2 and 3 failed to achieve excellent dielectric properties, moldability, and reflow heat resistance. As can be seen from Tables 1 and 2, the millimeter-wave antenna of this embodiment has excellent reflow heat resistance. Furthermore, the insulating film of this embodiment has a low relative dielectric constant and a low dielectric loss tangent, providing excellent dielectric properties. It can be said that a millimeter-wave antenna using this insulating film also has equivalent properties. Furthermore, the material used for the insulating film also has excellent moldability, resulting in high productivity. Furthermore, the material used for the insulating film of this embodiment has low water absorption, resulting in no or reduced risk of blistering during reflow, easy storage management, and minimal performance degradation even in a humid and hot environment.

Claims

1. An insulating film comprising a material containing a 3-methyl-1-butene polymer, and having a dielectric loss tangent of less than 0.00070 at 10 GHz to 300 GHz.

2. 2. The insulating film according to claim 1, 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 ethylene or an α-olefin, and the α-olefin has 3 to 20 carbon atoms.

3. 3. The insulating film according to claim 2, wherein the content of the structural units derived from ethylene or the α-olefin in the copolymer is more than 0 mol % and 20 mol % or less.

4. 3. The insulating film according to claim 2, wherein the content of the structural units derived from ethylene or the α-olefin in the copolymer is more than 0 mol % and 10 mol % or less.

5. 2. The insulating film according to claim 1, wherein the 3-methyl-1-butene polymer has a melting point of 260 to 310°C.

6. 2. The insulating film according to claim 1, wherein the material is a resin composition containing the 3-methyl-1-butene polymer and an alkyl radical scavenger.

7. The insulating film according to claim 6 , wherein the alkyl radical scavenger comprises at least one compound selected from the group consisting of an acrylphenol compound and a benzofuranone compound.

8. A copper-clad laminate comprising the insulating film according to any one of claims 1 to 7.

9. A millimeter wave antenna comprising the copper clad laminate of claim 8.

10. A millimeter wave antenna comprising the insulating film according to any one of claims 1 to 7.