Transparent substrate and transparent multilayer object

Abstract

A transparent substrate comprising a resin composition which includes a 3-methyl-1-butene-based polymer, and having a total light transmittance, as determined in accordance with JIS K 7375:2008, of 80% or greater.

Description

Transparent substrate and transparent laminate

[0001] The present invention relates to a transparent substrate and a transparent laminate.

[0002] In recent years, transparent substrates have been attracting attention among circuit board materials. Being transparent allows for a wide range of applications, such as touch sensors, dimming elements, photoelectric conversion elements, heat ray control components, antenna components, electromagnetic wave shielding components, heater components, lighting devices, and image display devices. Patent Document 1 describes a transparent conductive film substrate in which indium tin oxide (ITO) is coated on a polyethylene terephthalate (PET) film.

[0003] International Publication No. 2013 / 118875

[0004] In recent years, reflow soldering has been widely adopted in surface mounting processes in order to increase the density of integrated circuits. Because solder has a relatively high melting temperature, the temperature of the object to be soldered during reflow soldering must be set high, at 260°C or higher. Furthermore, in recent years, there has been a demand in the electrical and electronic fields for substrates with low relative permittivity and low dielectric loss tangent. The transparent conductive film substrate described in Patent Document 1 cannot be used in reflow processes because the melting point of the PET film constituting the substrate is 260°C. Furthermore, the dielectric properties of the substrate are such that the dielectric loss tangent is high, resulting in high losses, i.e., dielectric loss.

[0005] In view of the current situation, an object of the present invention is to provide a transparent substrate that is highly transparent, has a low relative dielectric constant and a low dielectric dissipation factor, and is capable of being reflow soldered, and a transparent laminate that includes the transparent substrate.

[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] A transparent substrate comprising a resin composition containing a 3-methyl-1-butene polymer, the transparent substrate having a total light transmittance of 80% or more as measured in accordance with JIS K 7375:2008. [2] The transparent substrate according to [1], wherein the 3-methyl-1-butene polymer has a melting point of 270 to 310°C. [3] The transparent substrate according to [1] or [2], 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. [4] The transparent substrate according to [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 20 mol%. [5] The transparent substrate according to [3] or [4], 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%. [6] The transparent substrate according to any one of [1] to [5], wherein the resin composition contains an alkyl radical scavenger. [7] The transparent substrate according to any one of [1] to [6], wherein the thickness is 0.1 to 1000 μm. [8] The transparent substrate according to any one of [1] to [7], wherein the 3-methyl-1-butene polymer contains structural units derived from 3-methyl-1-butene, and the content of the structural units derived from 3-methyl-1-butene in the 3-methyl-1-butene polymer is greater than 50 mol %. [9] A transparent laminate comprising the transparent substrate according to any one of [1] to [8], and a transparent conductive layer covering one or both sides of the transparent substrate.

[10] The transparent laminate according to [9], wherein the total light transmittance measured in accordance with JIS K 7375:2008 is 80% or more.

[0008] According to the present invention, it is possible to provide a transparent substrate that is highly transparent, has a low relative dielectric constant and a low dielectric loss tangent, and is capable of being reflow soldered, and a transparent laminate that includes the transparent substrate.

[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] <Transparent Substrate> The transparent substrate of this embodiment is a transparent substrate containing a resin composition containing a 3-methyl-1-butene polymer, and has a total light transmittance of 80% or more as measured in accordance with JIS K 7375:2008. The total light transmittance can be measured in detail by the method described in the examples. In this specification, the term "transparent substrate" refers to a transparent substrate having a total light transmittance of 80% or more as measured in accordance with JIS K 7375:2008. In other words, the transparent substrate of this embodiment has a total light transmittance of 80% or more even when it contains a resin composition containing a 3-methyl-1-butene polymer.

[0011] The resin composition of the transparent substrate contains a 3-methyl-1-butene polymer, which allows the transparent substrate to have high transparency, low dielectric constant and dielectric loss tangent, and low water absorption. Because the transparent substrate has low water absorption, it can be reflow soldered even after being left standing in an atmosphere of 85°C and 85% RH for 7 days.

[0012] The transparent substrate of the present embodiment may be made of only the resin composition, or may contain components other than the resin composition.

[0013] [Resin Composition] The resin composition of this embodiment contains a 3-methyl-1-butene polymer. When the resin composition contains a 3-methyl-1-butene polymer, it becomes possible to obtain a transparent substrate that has high transparency, a low dielectric constant, a low dielectric loss tangent, and is capable of being reflow soldered. In addition, since the 3-methyl-1-butene polymer has a small specific gravity, it is possible to achieve weight reduction.

[0014] The resin composition contains a 3-methyl-1-butene polymer and therefore has low water absorption. As a result, blisters do not occur during reflow soldering. Furthermore, even after leaving the resin composition standing in an atmosphere of 85°C and 85% RH for 7 days, the low water absorption allows reflow soldering and suppresses the occurrence of blisters. Furthermore, the resin composition does not require special storage conditions, and its low water absorption even under these conditions makes storage management easy.

[0015] <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. Examples of the unsaturated hydrocarbon include ethylene and 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. 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.

[0016] 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. Furthermore, from the viewpoint of heat resistance in reflow soldering, 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 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.

[0017] 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 heat resistance in reflow soldering, 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, more preferably 85 mol% or more, even more preferably 90 mol% or more, still more preferably 92 mol% or more, and even more preferably 93 mol% or more. Furthermore, from the viewpoint 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, and 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%, still more preferably 93 to 99.5 mol%, even more preferably 93 to 99.0 mol%, and most preferably 93.0 to 95.0%.

[0018] 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.

[0019] 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 3 to 20 carbon atoms may be used alone or in combination of two or more.

[0020] The melting point of the 3-methyl-1-butene polymer is preferably 270 to 310°C. When the melting point of the 3-methyl-1-butene polymer is within the above range, the resin composition can be easily molded by injection molding or the like, and warping, melting, and blistering of the transparent substrate due to reflow soldering are further suppressed, i.e., the reflow heat resistance is 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, it can be measured by the method described in the Examples. From the viewpoint of a balance between production efficiency and reflow heat resistance, the melting point of the 3-methyl-1-butene polymer is preferably 270 to 305°C, more preferably 280 to 305°C, and even more preferably 280 to 300°C.

[0021] <Melt Viscosity of 3-Methyl-1-Butene Polymer> 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. When the content of structural units derived from 3-methyl-1-butene in the 3-methyl-1-butene polymer is increased, the melt viscosity of the 3-methyl-1-butene polymer tends to increase. The melt viscosity of the 3-methyl-1-butene polymer of this embodiment was measured using a capillary rheometer at a barrel temperature of 320°C and a shear rate of 1220 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.

[0022] The content of the 3-methyl-1-butene polymer in 100% by mass of the resin composition is preferably 50.0 to 99.9% by mass, more preferably 60.0 to 99.9% by mass, even more preferably 65.0 to 99.9% by mass, and still more preferably 90.0 to 99.9% by mass, from the viewpoint of obtaining a transparent substrate having a lower relative dielectric constant and a lower dielectric dissipation factor. The content of the 3-methyl-1-butene polymer in the components of the resin composition excluding the filler is preferably 50.0 to 99.9% by mass, more preferably 60.0 to 99.9% by mass, even more preferably 65.0 to 99.9% by mass, and still more preferably 90.0 to 99.9% by mass, from the viewpoint of obtaining a transparent substrate having a lower relative dielectric constant and a lower dielectric dissipation factor.

[0023] 3-methyl-1-butene polymers have a relatively low specific gravity and can contribute to weight reduction of transparent substrates. 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.

[0024] <Alkyl Radical Scavenger> From the viewpoint of exhibiting better mechanical properties, the resin composition may contain an alkyl radical scavenger to the extent that the effects of the present invention are not impaired. In this embodiment, the term "alkyl radical scavenger" refers to a compound that reacts with an alkyl radical derived from a 3-methyl-1-butene polymer and then stabilizes the alkyl radical, thereby losing its ability to abstract hydrogen. From the viewpoint of exhibiting better mechanical properties, the alkyl radical scavenger preferably contains at least one selected from the group consisting of an acrylic phenol compound and a benzofuranone compound. One type of alkyl radical scavenger may be used alone, or two or more types may be used in combination.

[0025] (Acrylphenol Compound) The acrylic phenol compound used in this embodiment can be represented by, for example, the following general formula (I).

[0026]

[0027] 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.

[0028] 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.

[0029] (Benzofuranone Compound) The benzofuranone compound used in this embodiment can be represented by, for example, the following general formula (II).

[0030]

[0031] In general formula (II), R ７ and R ８ each independently represents 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.

[0032] 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.

[0033] (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. When the alkyl radical scavenger content is 0.01 part by mass or more, the physical properties of the resin composition can be more stably maintained during melt-kneading of the resin composition. In addition, generation of decomposition gas during melt molding, which can result in molding defects, can be suppressed. Furthermore, when the alkyl radical scavenger content is 1.00 part by mass or less, a transparent substrate with more excellent mechanical properties and transparency can be easily obtained. In addition, 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.

[0034] 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 a transparent substrate having a lower relative dielectric constant and a lower dielectric dissipation factor, 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.

[0035] <Antioxidant> From the viewpoint of ensuring the stability of the polymer, the resin composition may contain an antioxidant within a range that does not impair the effects of the present invention. The antioxidant preferably contains at least one selected from the group consisting of phenolic antioxidants, phosphorus-based antioxidants, and sulfur-based antioxidants, and more 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.

[0036] (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.

[0037] 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.

[0038] (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.

[0039] 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.

[0040] (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.

[0041] (Other Antioxidants) The resin composition may contain, or may not contain, other antioxidants than the phenolic antioxidant, phosphorus-based antioxidant, and sulfur-based antioxidant, as long as the effects of the present invention are not impaired. Examples of antioxidants other than the phenolic antioxidant, phosphorus-based antioxidant, and sulfur-based antioxidant include amine-based antioxidants.

[0042] (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 viewpoints of transparency, dielectric constant, and dielectric dissipation factor. That is, the content is preferably 0.01 to 1.00 parts by mass, more preferably 0.10 to 0.80 parts by mass. When the resin composition contains two or more antioxidants, the content of the antioxidants refers to the total content of the antioxidants.

[0043] <Other Additives> The resin composition may contain, or may not contain, other 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.

[0044] (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.

[0045] 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 2.0 parts by mass, 0.01 to 1.0 part by mass, 0.01 to 0.5 parts by mass, or 0.01 to 0.3 parts by mass.

[0046] (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.

[0047] 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 determined appropriately, and may be, for example, 5 parts by mass or less.

[0048] (Filler) The resin composition may or may not contain a filler from the viewpoint of further improving the mechanical properties of the transparent substrate. 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 transparent substrate. One filler may be used alone, or two or more fillers may be used in combination.

[0049] The content of the filler 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 300 parts by mass or 0.1 to 100 parts by mass.

[0050] (Ultraviolet Absorber) Examples of the ultraviolet absorber include 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, 4-(3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxy)-1-(2-(3-(3,5- hindered amine-based ultraviolet absorbers such as (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; 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; and the like.

[0051] 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 determined as appropriate and may be, for example, 0.001 to 5 parts by mass or 0.01 to 1 part by mass.

[0052] (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.

[0053] 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.

[0054] The content of the lubricant 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, 0.001 to 5 parts by mass or 0.005 to 3 parts by mass.

[0055] <Other Resins> The resin composition may or may not contain a resin other than the 3-methyl-1-butene polymer, as long as the effects of the present invention are not impaired. 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 a polyolefin with a reactive functional group such as maleic acid, in order to improve the dispersibility of additives containing polar groups. Examples of polyolefins constituting the modified polyolefin modified with a reactive functional group include polyethylene, polypropylene, and polyolefins having an α-olefin having 3 to 20 carbon atoms as a structural unit. 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.

[0056] 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.

[0057] 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.

[0058] <Melting Point of Resin Composition> The melting point of the resin composition of this embodiment is preferably 270 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 balancing production efficiency and reflow 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. The preferred range of the melting point of the transparent substrate is also the same as the preferred range of the melting point of the resin composition. The method for measuring the melting point of the transparent substrate is also as described above, and specifically, it can be measured by the method described in the Examples.

[0059] <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.

[0060] <Dielectric Loss Tangent of Transparent Substrate> The dielectric loss tangent of the transparent substrate of this embodiment refers to the dielectric loss tangent measured at a specific frequency, specifically, the dielectric loss tangent measured at a frequency of 10 kHz to 300 GHz. From the viewpoint of economy, the dielectric loss tangent at 10 kHz to 300 GHz is preferably 0.00010 or more, more preferably 0.00013 or more, and even more preferably 0.00015 or more. From the viewpoint of reducing transmission loss, it is preferably 0.00100 or less, more preferably 0.00080 or less, and even more preferably 0.00050 or less. That is, the dielectric loss tangent at 10 kHz to 300 GHz is preferably 0.00010 to 0.00100, more preferably 0.00013 to 0.00080, and even more preferably 0.00015 to 0.00050. The dielectric loss tangent of the transparent substrate at 10 kHz 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 measurement frequency is 10 kHz to 1 GHz, measurement is preferably performed by a capacitance method, and when the measurement frequency is 1 GHz to 300 GHz, measurement is preferably performed by a resonance method or a frequency variation method. The dielectric loss tangent of the transparent substrate at 10 GHz measured by the cavity resonance method, the dielectric loss tangent of the transparent substrate at 100 GHz measured by the frequency variation method, and the dielectric loss tangent of the transparent substrate at 200 GHz measured by the frequency variation method are each preferably 0.00010 to 0.00100, more preferably 0.00013 to 0.00080, and even more preferably 0.00015 to 0.00050. That is, in one aspect, the transparent substrate of this embodiment has a dielectric loss tangent at 10 GHz measured by a resonance method of preferably 0.00010 to 0.00100, more preferably 0.00013 to 0.00080, and even more preferably 0.00015 to 0.00050. In one aspect, the transparent substrate of this embodiment has a dielectric loss tangent at 100 GHz measured by a frequency variation method of preferably 0.00010 to 0.00100, more preferably 0.00013 to 0.00080, and even more preferably 0.00015 to 0.00050.In one aspect, the transparent substrate of this embodiment has a dielectric loss tangent at 200 GHz, measured by a frequency variation method, of preferably 0.00010 to 0.00100, more preferably 0.00013 to 0.00080, and even more preferably 0.00015 to 0.00050. The preferred range of the dielectric loss tangent of the resin composition is the same as the preferred range of the dielectric loss tangent of the transparent substrate. The method for measuring the dielectric loss tangent of the resin composition is also as described above, and specifically, it can be measured by the method described in the examples.

[0061] <Dielectric Constant of Transparent Substrate> The dielectric constant of the transparent substrate of this embodiment refers to the dielectric constant measured at a specific frequency, specifically, the dielectric constant measured at a frequency of 10 kHz to 300 GHz. From the viewpoint of economy, the dielectric constant at 10 kHz 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, it is preferably 5.0 or less, more preferably 4.0 or less, even more preferably 3.8 or less, and even more preferably 3.5 or less. That is, the dielectric constant at 10 kHz 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 dielectric constant of the transparent substrate at 10 kHz 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 specifically, it can be measured by the method described in the examples. When the measurement frequency is 10 kHz to 1 GHz, measurement is preferably performed by the capacitance method, and when the measurement frequency is 1 GHz to 300 GHz, measurement is preferably performed by the resonance method or the frequency variation method. The relative dielectric constant of the transparent substrate at 10 GHz measured by the resonance method, the relative dielectric constant of the transparent substrate at 100 GHz measured by the frequency variation method, and the relative dielectric constant of the transparent substrate at 200 GHz measured by the frequency variation method are each preferably 0.5 to 5.0, more preferably 1.5 to 4.0, and even more preferably 2.0 to 3.5. That is, in one aspect, the relative dielectric constant of the transparent substrate of this embodiment at 10 GHz measured by the resonance method is preferably 0.5 to 5.0, more preferably 1.5 to 4.0, and even more preferably 2.0 to 3.5. In one aspect, the relative dielectric constant of the transparent substrate of this embodiment at 100 GHz measured by the frequency variation method is preferably 0.5 to 5.0, more preferably 1.5 to 4.0, and even more preferably 2.0 to 3.5. In one aspect, the transparent substrate of this embodiment has a relative dielectric constant at 200 GHz measured by a frequency variation method of preferably 0.5 to 5.0, more preferably 1.5 to 4.0, and even more preferably 2.0 to 3.5. The preferred range of the relative dielectric constant of the resin composition is the same as the preferred range of the relative dielectric constant of the transparent substrate described above.The method for measuring the relative dielectric constant of the resin composition is also as described above, and specifically, it can be measured by the method described in the Examples.

[0062] <Water Absorption of Transparent Substrate> The water absorption of the transparent substrate 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 of the transparent substrate 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 of the transparent substrate refers to a value measured in accordance with Method A of JIS K 7209:2000, and can be measured specifically by the method described in the Examples. The preferred range of the water absorption of the resin composition is also the same as the preferred range of the water absorption of the transparent substrate. The method for measuring the water absorption of the resin composition is also as described above, and can be measured specifically by the method described in the Examples.

[0063] <Method for Producing Transparent Substrate> The method for producing the transparent substrate of this embodiment is not particularly limited as long as it is a method for producing the above-described transparent substrate. From the viewpoint of obtaining a transparent substrate that has high transparency, a low dielectric constant, a low dielectric loss tangent, and is reflow solderable, the method for producing the transparent substrate preferably includes a step of obtaining a 3-methyl-1-butene polymer and a step of obtaining the transparent substrate by molding the resin composition. Furthermore, when the resin composition is obtained by blending other components such as additives in addition to the 3-methyl-1-butene polymer, it is preferable to go through the step of obtaining the resin composition described below.

[0064] [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 an α-olefin, to obtain 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.

[0065] [Step of Obtaining Resin Composition] The step of obtaining a resin composition is a step of blending and mixing other components such as additives in addition to the 3-methyl-1-butene polymer 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 blending 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 when no other components are blended in addition to the 3-methyl-1-butene polymer, the resin composition consists of the 3-methyl-1-butene polymer, and there is no need to go through the step of obtaining a resin composition. Examples of the additives include those similar to 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, ultraviolet absorbers, nucleating agents, clarifying agents, lubricants, fluorescent brighteners, rust inhibitors, and sliding agents.

[0066] <Melt-Kneading Conditions> The melt-kneading conditions are not particularly limited, but it is preferable to inject an inert gas into the melt-kneader to perform the melt-kneading, or to degas the inside of the melt-kneader under reduced pressure. In order to suppress the deterioration of the physical properties of the resin composition due to oxygen and produce a transparent substrate with better mechanical properties, it is preferable to perform the 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] [Step of Obtaining a Transparent Substrate] In this embodiment, the step of obtaining a transparent substrate is a step of obtaining a transparent substrate by molding a resin composition. The molding method is not particularly limited, and a method appropriate for the shape of the transparent substrate may be used. The resin composition of this embodiment is thermoplastic and can be melt-molded. Therefore, injection molding, extrusion molding, pressure molding, hot press molding, etc. can be used. Among these, extrusion molding is preferred from the viewpoint of ease of production and obtaining molded products with excellent dimensional accuracy. The extrusion molding may be single-screw extrusion or twin-screw extrusion, and in one embodiment, twin-screw extrusion using a twin-screw extruder is preferred.

[0074] <Shape of Transparent Substrate> There are no particular limitations on the shape (dimensions) of the transparent substrate. The thickness of the transparent substrate may be 0.1 to 1000 μm, 1 to 500 μm, 1 to 300 μm, or 5 to 100 μm.

[0075] <Transparent Laminate> The transparent laminate of this embodiment is a transparent laminate including the transparent substrate of this embodiment and a transparent conductive layer covering one or both sides of the transparent substrate. The transparent laminate preferably has a total light transmittance of 80% or more as measured in accordance with JIS K 7375:2008. The term "covering" refers to covering to an extent that the transparent conductive layer has conductivity, and may cover a part of the surface of the transparent substrate or the entire surface.

[0076] [Transparent Conductive Layer] The transparent conductive layer may be a layer containing a transparent conductive material, such as a transparent conductive oxide or a conductive polymer, or a thin transparent metal layer. Examples of transparent conductive oxides include metal oxides containing at least one metal or semimetal selected from the group consisting of In, Sn, Zn, Ga, Sb, Ti, Si, Zr, Mg, Al, Au, Ag, Cu, Pd, and W. Specifically, conductive oxides include indium-containing conductive oxides and antimony-containing conductive oxides. Examples of indium-containing conductive oxides include indium tin composite oxide (ITO), indium zinc composite oxide (IZO), indium gallium composite oxide (IGO), and indium gallium zinc composite oxide (IGZO). Examples of antimony-containing conductive oxides include antimony tin composite oxide (ATO). Examples of conductive polymers include poly(3,4-ethylenedioxythiophene) (PEDOT), poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), and poly(4,4-dioctylcyclopentadithiophene). Examples of thin transparent metal layers include silver. The transparent conductive material is preferably a transparent conductive oxide, more preferably indium tin oxide (ITO), from the viewpoint of achieving high transparency and good conductivity. This ITO may contain metals or semimetals other than In and Sn in amounts less than the respective contents of In and Sn. The transparent conductive layer is preferably formed using a coating method or a sputtering method in which the layer is applied to the substrate by a coating process. For example, ITO is typically applied by sputtering to a thickness ranging from 0.005 μm to 250 μm. The thickness of the transparent conductive layer may be 0.01 to 1.00 μm, 0.03 to 0.30 μm, 0.04 to 0.15 μm, or 0.04 to 0.10 μm.

[0077] [Method for Producing a Transparent Laminate] While there are no particular limitations on the method for producing a transparent laminate, it can be produced by coating one or both sides of a transparent substrate with a transparent conductive layer. That is, it can be produced by forming a transparent conductive layer so as to cover at least a portion of one or both sides of a transparent substrate. The transparent laminate may be formed from multiple layers as long as the effects of the present invention are not impaired. That is, the transparent laminate may have layers other than the transparent substrate and the transparent conductive layer. Layers other than the 3-methyl-1-butene polymer, i.e., layers other than the transparent substrate and the transparent conductive layer, may be, for example, hard coat layers that improve the scratch resistance of the transparent conductive layer, adhesion-improving layers that improve the adhesion between the transparent substrate and the transparent conductive layer, refractive index-adjusting layers that adjust the reflectance of the transparent substrate, or release-functional layers that facilitate peeling of the transparent substrate and the transparent conductive layer. Furthermore, the layers other than the transparent substrate and the transparent conductive layer may include two or more of these, or may be composite layers composed of two or more layers. In the transparent laminate, the surfaces between layers and the surfaces to be coated with the transparent conductive layer may or may not be surface-treated before coating, but from the viewpoint of firmly bonding the transparent substrate between layers and between the transparent substrate and the transparent conductive layer, surface treatment is preferred. Examples of surface treatments include corona treatment, plasma treatment, ozone treatment, primer treatment, glow treatment, and coupling agent treatment.

[0078] [Uses of Transparent Laminate] The transparent laminate is used in various applications, such as touch sensors, electromagnetic wave shields, dimming elements (e.g., voltage-driven dimming elements such as PDLC, PNLC, and SPD, and current-driven dimming elements such as electrochromic (EC)), photoelectric conversion elements (e.g., electrodes of solar cell elements typified by organic thin-film solar cells and dye-sensitized solar cells), heat ray control members (e.g., near-infrared reflective and / or absorbing members, e.g., far-infrared reflective and / or absorbing members), antenna members (light-transmitting antennas), heater members (light-transmitting heaters), image display devices, and lighting.

[0079] The present invention will be specifically explained below with reference to examples and comparative examples, but the present invention is not limited to these.

[0080] <Measurement and Evaluation Methods> Various physical properties were measured or evaluated by the following methods.

[0081] [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 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 3-methyl-1-butene polymer obtained in Production Example 1, and the resulting measured value (peak area ratio) was inserted into the calibration curve to determine the content of structural units derived from α-olefins other than 3-methyl-1-butene (1-decene).

[0082] [Melting Point] Using a differential scanning calorimeter ("DSC25" manufactured by TA Instruments), the polymers (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 polymers were heated 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.

[0083] [Melt Viscosity] The melt viscosity (Pa s) of the polymers (3-methyl-1-butene polymers) obtained in Production Examples 1 to 3 and the polymers obtained in Examples 1 to 3 was measured using a capillary rheometer ("Capillography 1C" manufactured by Toyo Seiki Seisakusho, 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).

[0084] [Specific Gravity] The resin compositions obtained in Examples 1 to 3 and the resin compositions used in Comparative Examples 1 and 2 were press-molded at a press temperature of 320°C and a press pressure of 1.8 MPa to prepare test pieces (length: 40 mm, width: 10 mm, thickness: 4 mm). For the resin of Comparative Example 3, a test piece of the same shape was prepared by compression molding. Using the test piece, the specific gravity was measured in accordance with JIS K 7112:1999 Method A.

[0085] [Water absorption rate] The resin compositions obtained in Examples 1 to 3 and the resin compositions used in Comparative Examples 1 and 2 were press-molded at a press temperature of 320°C and a press pressure of 1.8 MPa to prepare test pieces (length: 60 mm, width: 60 mm, thickness: 1 mm). For the resin of Comparative Example 3, a test piece of the same shape was prepared by compression molding. Using the test piece, the water absorption rate was measured in accordance with JIS K 7209:2000 Method A.

[0086] [Relative permittivity and dielectric loss tangent] The resin compositions used in Examples 1 to 3 and Comparative Examples 1 and 2 were injection molded at a cylinder temperature of 320°C and a mold temperature of 180°C to prepare test pieces (length: 30 mm, width: 1.5 mm, thickness: 1 mm). For the resin of Comparative Example 3, a test piece of the same shape was prepared by compression molding. Using the test piece, the relative permittivity and dielectric loss tangent at a measurement frequency of 10 GHz were measured using a PNA series network analyzer "Keysight E8361A" (manufactured by Agilent Technologies) by a perturbation cavity resonance method. In addition, the resin compositions used in Examples 1 to 3 were injection molded at a cylinder temperature of 320°C and a mold temperature of 180°C to prepare test pieces (length: 40 mm, width: 40 mm, thickness: 0.5 mm). Using the test piece, the relative permittivity and dielectric loss tangent at a measurement frequency of 100 GHz were measured by a frequency variation method using a millimeter-wave module (WR10 67 GHz to 115 GHz, manufactured by Virginia Diodes Inc.). Furthermore, the resin compositions used in Examples 1 to 3 were injection molded at a cylinder temperature of 320°C and a mold temperature of 180°C to produce test pieces (length: 40 mm, width: 40 mm, thickness: 0.5 mm). Using the test piece, the relative permittivity and dielectric loss tangent at a measurement frequency of 200 GHz were measured by a frequency variation method using a vector network analyzer (Anritsu ME7838G 70 kHz to 220 GHz).

[0087] [Reflow Heat Resistance] The resin compositions obtained in Examples 1 to 3 and Comparative Examples 1 and 2 were press-molded at a press temperature of 320°C and a press pressure of 1.8 MPa to prepare test pieces (length: 30 mm, width: 5 mm, thickness: 1 mm). For the resin of Comparative Example 3, a test piece of the same shape was prepared by compression molding. The test piece was left to stand for 7 days in an atmosphere of 85°C and 85% RH. After standing, the test piece was heat-treated using a high-temperature observation device "SMT Scope Light SL-1" (manufactured by Sanyo Seiko Co., Ltd.) with the following reflow temperature profile, and the appearance of the test piece was observed and evaluated. Specifically, a test piece in which at least one of warping, melting, and blisters was observed was rated B, and a test piece in which none of the warping, melting, and blisters 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, followed by air cooling.

[0088] [Transparency] For the transparent substrates obtained in the Examples and Comparative Examples, the total light transmittance was measured according to JIS K 7375:2008 using a haze meter HZ-V3 (manufactured by Suga Test Instruments Co., Ltd.). The evaluation results are shown in Table 1. A total light transmittance of 80% or more was rated A, and a total light transmittance of less than 80% was rated B. <Thickness of Transparent Conductive Layer> The thickness of the transparent conductive layer in the transparent laminates of the Examples and Comparative Examples was measured by FE-TEM observation. Specifically, first, samples for cross-sectional observation of the transparent laminates of the Examples and Comparative Examples were prepared by FIB microsampling. In the FIB microsampling method, an FIB device (trade name "FB2200", manufactured by Hitachi) was used, and the acceleration voltage was set to 10 kV. Next, the thickness of the transparent conductive layer in the sample for cross-sectional observation was measured by FE-TEM observation. For the FE-TEM observation, an FE-TEM device (trade name "JEM-2800", manufactured by JEOL) was used, and the acceleration voltage was set to 200 kV.

[0089] [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.

[0090] [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%.

[0091] [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%.

[0092] [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.

[0093] Example 1 Production of Resin Composition (M1) 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. After dry blending with 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 as an antacid, the mixture was melt-kneaded using a small kneader "Micro 15 Compounder" (manufactured by DSMXplore) to obtain a pellet-shaped resin composition (M1). The melt viscosity of the obtained resin composition (M1) was 104 Pa s.

[0094]

[0049] The obtained resin composition (M1) was molded under the following film-forming conditions to obtain a transparent substrate. Specifically, the pellets were supplied to a twin-screw extruder "Twin-screw kneading extruder KZW15-45" (manufactured by Technovel Co., Ltd.), melt-kneaded at a cylinder temperature of 310°C under a nitrogen atmosphere, 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 a transparent substrate having a thickness of 200 μm.

[0095]

[0049] After cutting both ends of the obtained transparent substrate, one surface was subjected to a corona discharge treatment. A layer of indium tin oxide was formed on the corona discharge-treated surface of this film by the sputtering method described below, to produce a transparent laminate. The obtained transparent laminate was evaluated. The results are shown in Table 1.

[0096] Manufacture of indium tin oxide by sputtering method The indium tin oxide thin film layer was formed by sputtering. A sputtering film formation apparatus (DC magnetron sputtering apparatus) was used, and a sintered body of indium oxide and tin oxide (tin oxide concentration: 10 mass %) was used as the target. A DC power supply was used as the power source for applying voltage to the target. The film formation temperature (temperature of the transparent substrate) was 20°C. The ultimate vacuum in the film formation chamber of the apparatus was 0.8 × 10 －４ After evacuating the film formation chamber to a pressure of 0.2 Pa, Ar as a sputtering gas and oxygen as a reactive gas were introduced into the film formation chamber, and the pressure inside the film formation chamber was adjusted to 0.2 Pa. Next, the indium tin oxide thin film layer was crystallized by heating in a hot air oven. In this process, the heating temperature was 130°C and the heating time was 1.5 hours. The thickness of the transparent conductive layer was 0.043 μm.

[0097] [Examples 2 and 3] Resin composition (M2) (Example 2) and resin composition (M3) (Example 3) were obtained in the same manner as in Example 1, except that the types of resins were as shown in Table 1. Next, transparent substrates and transparent laminates were produced and evaluated in the same manner as in Example 1, except that resin compositions (M2) to (M3) were used instead of resin composition (M1). The results are shown in Table 1. The melt viscosity of resin composition (M2) was 99 Pa·s, and the melt viscosity of resin composition (M3) was 126 Pa·s. The thickness of the transparent conductive layer in Example 2 was 0.050 μm, and the thickness of the transparent conductive layer in Example 3 was 0.053 μm.

[0098] Comparative Example 1 A transparent laminate was produced and evaluated in the same manner as in Example 1, except that a PET film (O3, manufactured by Teijin DuPont Co., Ltd., thickness 100 μm) was used as the transparent substrate. The results are shown in Table 1. The thickness of the transparent conductive layer was 0.054 μm.

[0099] Comparative Example 2 A transparent laminate was produced and evaluated in the same manner as in Example 1, except that polymethylpentene (TPX) (MX002O, manufactured by Mitsui Chemicals) was used instead of the resin composition (M1), and the film formation conditions were a cylinder temperature of 270°C and a cooling roll temperature of 80°C. The results are shown in Table 1. The thickness of the transparent substrate was 200 μm. The thickness of the transparent conductive layer was 0.066 μm.

[0100] Comparative Example 3 One mole of 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl (TFMB) was dissolved in 80 g of N,N-diethylformamide (DEF), to which 1 mole of 4,4'-oxydiphthalic anhydride (ODPA) was added. The mixture was then added to 50 g of DEF and polymerized at 50°C for 24 hours to produce a solution containing polyamic acid. 40 g of toluene was added to the solution, and the solution was set up to remove water using a Dean-Stark distillation apparatus. The mixture was refluxed at 180°C for 12 hours to obtain a polyimide solution. Methanol solvent was added to the polyimide solution to form a precipitate, which was then dried to obtain TFMB-ODPA polyimide. To 10 g of the resulting polyimide, 5 g of urethane acrylic oligomer SU594 (manufactured by Soltec Corporation) and 4 g of dipentaerythritol hexaacrylate (DPHA) were added, followed by mixing with 1 g of a thermal initiator (2,2'-azobis(2,4-dimethylvaleronitrile) V65 (manufactured by Wako Pure Chemical Industries, Ltd., half-life 10 hours, half-life temperature 50°C) and DEF to a solids concentration of 30% by mass, to prepare a thermosetting resin composition. The resulting thermosetting resin composition was spin-coated onto a glass substrate (thickness 50 μm). The substrate was then heated to 250°C at a heating rate of 3°C / min in an oven under a nitrogen atmosphere, followed by heat treatment for 60 minutes and peeled off from the glass substrate to prepare a polyimide (PI) film. The thickness was 210 μm as measured with a micrometer. Thereafter, a transparent laminate was produced and evaluated in the same manner as in Example 1, except that a polyimide (PI) film was used as the transparent substrate. The results are shown in Table 1. The thickness of the transparent conductive layer was 0.063 μm.

[0101]

[0102] As shown in the examples, a transparent laminate containing a resin composition containing the 3-methyl-1-butene polymer of this embodiment has transparency, a low dielectric constant, a low dielectric loss tangent, and is reflow solderable. Therefore, it is suitable for application to the transparent circuit board of this embodiment. Furthermore, because of its low water absorption, no blisters occur during reflow soldering, storage management is easy, and performance degradation is minimal even in a humid and hot environment. Furthermore, its excellent processability allows for high productivity.

Claims

1. A transparent substrate including a resin composition containing a 3-methyl-1-butene polymer, A transparent substrate having a total light transmittance of 80% or more as measured based on JIS K 7375:2008.

2. 2. The transparent substrate according to claim 1, wherein the melting point of the 3-methyl-1-butene polymer is 270 to 310°C.

3. 3. The transparent substrate 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.

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

5. 4. The transparent substrate according to claim 3, 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.

6. The transparent substrate according to claim 1 or 2, wherein the resin composition contains an alkyl radical scavenger.

7. 3. The transparent substrate according to claim 1, having a thickness of 0.1 to 1000 μm.

8. 3. The transparent substrate according to claim 1, wherein the 3-methyl-1-butene polymer contains structural units derived from 3-methyl-1-butene, and the content of the structural units derived from 3-methyl-1-butene in the 3-methyl-1-butene polymer is more than 50 mol%.

9. A transparent laminate comprising the transparent substrate according to claim 1 or 2 and a transparent conductive layer covering one or both sides of the transparent substrate.

10. The transparent laminate according to claim 9, which has a total light transmittance of 80% or more as measured in accordance with JIS K 7375:2008.