Resin composition and sheet for heat-radiating circuit board

Abstract

This resin composition contains a 3-methyl-1-butene polymer and a highly heat conductive inorganic filler having a heat conductivity of 20 W / m·K or greater.

Description

Resin composition and heat-dissipating circuit board sheet

[0001] The present invention relates to a resin composition and a heat-dissipating sheet for circuit boards.

[0002] 3-methyl-1-butene polymers are expected to be used in a wide range of applications in the electrical and electronic fields, particularly in circuit boards, due to their low dielectric constant, low dielectric loss tangent, high reflow resistance, etc. Patent Document 1 describes a double-sided metal-clad dielectric substrate for a planar antenna, which includes a dielectric layer containing a 3-methyl-1-butene polymer.

[0003] Japanese Unexamined Patent Publication No. 63-086320

[0004] In recent years, heat generation due to the increasing density of integrated circuits has become a major problem in the electrical and electronic fields, and how to dissipate heat has become an urgent issue. Because 3-methyl-1-butene polymers have low thermal conductivity, their use in these fields requires improved thermal conductivity. However, Patent Document 1 does not disclose any information regarding thermal conductivity. Furthermore, Patent Document 1 describes an example of a substrate including a film formed from a 3-methyl-1-butene polymer mixed with 20% by weight of glass microballoons. However, because glass microballoons exhibit relatively low thermal conductivity, the effect of improving the thermal conductivity of the film cannot be expected. Furthermore, in recent years, reflow soldering has become widely adopted in surface mounting processes in light of the increasing 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.

[0005] In view of the current situation, the present invention aims to provide a resin composition that can be used to produce a sheet that has high thermal conductivity, a low dielectric constant and a low dielectric loss tangent, and that can be reflow soldered, and a sheet that contains the resin composition and that can be suitably used as a heat-dissipating circuit board.

[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 resin composition comprising a 3-methyl-1-butene polymer and a highly thermally conductive inorganic filler having a thermal conductivity of 20 W / m K or more. [2] The resin composition 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, wherein the α-olefin is an α-olefin having 3 to 20 carbon atoms. [3] The resin composition according to [2], wherein the copolymer contains structural units derived from ethylene or an α-olefin at a ratio of more than 0 mol% to 20 mol% or less. [4] The resin composition according to [2] or [3], wherein the copolymer contains structural units derived from ethylene or an α-olefin at a ratio of more than 0 mol% to 10 mol% or less. [5] The resin composition according to any one of [1] to [4], wherein the 3-methyl-1-butene polymer has a melting point of 260°C to 310°C. [6] The resin composition according to any one of [1] to [5], wherein the content of the highly thermally conductive inorganic filler is 10 to 95% by volume. [7] The resin composition according to any one of [1] to [6], wherein the highly thermally conductive inorganic filler is one or more selected from the group consisting of boron nitride, aluminum nitride, and aluminum oxide. [8] The resin composition according to any one of [1] to [7], wherein the highly thermally conductive inorganic filler is boron nitride. [9] The resin composition according to any one of [1] to [8], wherein the content of the structural unit derived from 3-methyl-1-butene in 100 mol% of the copolymer is more than 50 mol%.

[10] A sheet comprising the resin composition according to any one of [1] to [9].

[11] The sheet according to

[10] , which is for use in a heat-dissipating circuit board.

[12] A metal foil-attached substrate comprising the sheet according to

[10] or

[11] .

[13] A circuit board comprising the sheet according to

[10] or

[11] .

[14] A method for producing a resin composition, comprising producing a resin composition containing a 3-methyl-1-butene polymer and a highly thermally conductive inorganic filler having a thermal conductivity of 20 W / m·K or more.

[0008] According to the present invention, it is possible to provide a resin composition that can be used to produce a sheet that has high thermal conductivity, a low dielectric constant and a low dielectric loss tangent, and that can be reflow soldered, and a sheet that contains the resin composition and is suitable for use as a heat-dissipating circuit board.

[0009] The present invention will be described below 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] [Resin Composition] The resin composition of this embodiment contains a 3-methyl-1-butene polymer and a highly thermally conductive inorganic filler having a thermal conductivity of 20 W / m·K or more. By including a 3-methyl-1-butene polymer in the resin composition, it is possible to obtain a sheet that has a low relative dielectric constant and a low dielectric dissipation factor and is reflow solderable. Furthermore, by including a highly thermally conductive inorganic filler having a thermal conductivity of 20 W / m·K or more in the resin composition, it is possible to obtain a sheet with high thermal conductivity. Furthermore, because the 3-methyl-1-butene polymer has a low specific gravity, weight reduction can be achieved. The resin composition of this embodiment is suitable for use as a sheet for heat-dissipating circuit boards.

[0011] 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.

[0012] <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.

[0013] 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 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.

[0014] 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 but 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, even more preferably 99.5 mol% or less, still more preferably 99.0 mol% or less, and even more preferably 95.0 mol%. From these viewpoints, the content of structural units derived from 3-methyl-1-butene in 100 mol% of the copolymer is more preferably 85 to 99.9 mol%, even more preferably 90 to 99.5 mol%, still more preferably 92 to 99.5 mol%, even more preferably 93 to 99.5 mol%, even more preferably 93 to 99.0 mol%, and still more preferably 93.0 to 95.0%.

[0015] 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.

[0016] 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 even more preferably 1-decene. Ethylene or the α-olefin having 3 to 20 carbon atoms may be used alone or in combination of two or more.

[0017] 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 resin composition can be easily molded by injection molding or the like, and furthermore, warping, melting, and the occurrence of blisters and the like of the sheet 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.

[0018] <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 the present 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.

[0019] The content of the 3-methyl-1-butene polymer in the components of the resin composition excluding the highly thermally conductive inorganic filler is preferably 50.0 to 99.9 mass%, more preferably 60.0 to 99.9 mass%, even more preferably 65.0 to 99.9 mass%, and even more preferably 90.0 to 99.9 mass%, based on the total amount of the resin composition excluding the highly thermally conductive inorganic filler, taken as 100 mass%, from the viewpoint of obtaining a sheet having a lower dielectric constant and a lower dielectric dissipation factor. The content of the 3-methyl-1-butene polymer in 100 mass% of the resin composition is preferably 1.0 to 80.0 mass%, more preferably 3.0 to 70.0 mass%, even more preferably 5.0 to 40.0 mass%, even more preferably 5.0 to 15.0 mass%, and even more preferably 7.0 to 10.0 mass%, from the viewpoint of obtaining a sheet having a lower dielectric constant and a lower dielectric dissipation factor.

[0020] 3-methyl-1-butene polymers have a relatively low specific gravity and can contribute to reducing the weight of sheets. 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.

[0021] <High Thermal Conductivity Inorganic Filler> The resin composition contains a high thermal conductivity inorganic filler. Hereinafter, this will also be referred to simply as "inorganic filler" or "filler." When the resin composition contains a high thermal conductivity inorganic filler, it becomes possible to obtain a sheet with high thermal conductivity and excellent mechanical properties. In the present invention, the high thermal conductivity inorganic filler refers to an inorganic filler having a thermal conductivity of 20 W / m·K or more, preferably 40 W / m·K or more. The thermal conductivity of the high thermal conductivity inorganic filler can be measured, for example, at 25°C using a laser flash method in accordance with JIS R 1611:2010. Examples of high thermal conductivity inorganic fillers include diamond, silicon carbide, titanium carbide, tungsten carbide, magnesium oxide, aluminum oxide, zinc oxide, yttrium oxide, ytterbium oxide, beryllium oxide, sialon (ceramics composed of silicon, aluminum, oxygen, and nitrogen), boron nitride, aluminum nitride, silicon nitride, and carbon fiber. Among these, boron nitride, aluminum nitride, and aluminum oxide are preferred, with boron nitride being more preferred, from the viewpoint of obtaining a sheet that is relatively inexpensive, has high thermal conductivity, and is excellent in mechanical properties. These highly thermally conductive inorganic fillers may be surface-treated with, for example, a silane coupling agent. Furthermore, to improve the dispersibility of the highly thermally conductive inorganic filler, a compatibilizer may be used in the resin composition. The inorganic filler may be used alone or in combination of two or more types.

[0022] The content of the highly thermally conductive inorganic filler in the resin composition relative to 100 parts by mass of the 3-methyl-1-butene polymer is preferably 50 to 2,000 parts by mass. When the content of the highly thermally conductive inorganic filler is 50 parts by mass or more, a sheet having high thermal conductivity and excellent mechanical properties can be obtained. When the content of the highly thermally conductive inorganic filler is 2,000 parts by mass or less, the moldability of the resin composition can be maintained. From the above viewpoints, the content of the highly thermally conductive inorganic filler in the resin composition relative to 100 parts by mass of the 3-methyl-1-butene polymer is more preferably 100 to 2,000 parts by mass, even more preferably 200 to 2,000 parts by mass, more preferably 250 to 2,000 parts by mass, more preferably 500 to 2,000 parts by mass, and more preferably 800 to 1,500 parts by mass. Alternatively, it is preferably 250 to 1,500 parts by mass, more preferably 300 to 1,500 parts by mass, and even more preferably 300 to 1,200 parts by mass. From the same viewpoint, the content of the high thermal conductive inorganic filler in 100% by mass of the resin composition is preferably 20.0 to 98.0% by mass, more preferably 30.0 to 96.0% by mass, more preferably 50.0 to 94.0%, even more preferably 60.0 to 94.0% by mass, even more preferably 75.0 to 94.0% by mass, and even more preferably 89.0 to 92.0% by mass. From the same viewpoint, the content of the high thermal conductive inorganic filler in 100% by volume of the resin composition is preferably 10 to 95% by volume, more preferably 30 to 90% by volume, even more preferably 35 to 90% by volume, even more preferably 40 to 90% by volume, and even more preferably 45 to 85% by volume.

[0023] <Alkyl Radical Scavenger> The resin composition may contain an alkyl radical scavenger from the viewpoint of exhibiting better mechanical properties. 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 compound 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 ６ each 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 , R４ , 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 an alkyl group having 1 to 4 carbon atoms; R ９ and R １０each 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. 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 can result in molding defects, can be suppressed. Furthermore, when the alkyl radical scavenger content is 1.00 parts by mass or less, a sheet with more excellent mechanical properties can be easily obtained. Furthermore, bleeding out of the alkyl radical scavenger or deterioration of the physical properties required of the resin composition, such as deterioration of moisture absorption and thermal conductivity, 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 per 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 sheet having a lower relative dielectric constant and a lower dielectric dissipation factor, the content of the alkyl radical scavenger in the resin composition per 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 per 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, 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.

[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, 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.

[0042] <Other Additives> The resin composition may or may not 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 type of the other additives may be used alone, or two or more types 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 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.

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

[0047] (Filler) The resin composition may contain a filler to further improve the mechanical properties of the sheet. Examples of fillers include fibrous compounds such as glass fiber, resin fiber, and cellulose fiber; plate-like compounds such as mica, talc, and montmorillonite; spherical compounds such as glass beads, shirasu balloons, and acrylic balloons; needle-like 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, and silica. These fillers may be surface-treated with, for example, a silane coupling agent. A compatibilizer may also be used to improve the dispersibility of the filler. Note that the "highly thermally conductive inorganic filler" is not included in the "lubricant." Among these, glass fiber is preferred to further improve the mechanical properties of the sheet. 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 determined appropriately and may be, for example, 0.01 to 300 parts by mass or 0.1 to 100 parts by mass.

[0049] (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.

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

[0051] (Lubricant) Inorganic fine particles are generally used as the lubricant. Examples of inorganic fine particles include oxides, hydroxides, sulfides, nitrides, halides, carbonates, sulfates, acetates, phosphates, phosphites, organic carboxylates, silicates, titanates, borates, and their hydrated compounds, composite compounds containing these, and natural minerals, etc., of elements in Groups 1, 2, 4, 6, 7, 8 to 10, 11, 12, 13, and 14 of the periodic table. Note that the "highly thermally conductive inorganic filler" is not included in the "lubricant." The "highly thermally conductive inorganic filler" and "lubricant" contained in a resin composition can be distinguished, for example, by incinerating the resin composition and measuring the thermal conductivity of the resulting residue.

[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 chloride, magnesium acetate, magnesium fluoride, magnesium titanate, magnesium silicate, magnesium silicate hydrate, 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; Examples of inorganic fine particles include Group 4 element compounds such as titanium dioxide (titania), titanium monoxide, 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 acetate; Group 13 element compounds such as aluminum hydroxide, aluminum fluoride, and aluminosilicates (alumina silicate, kaolin, and kaolinite); Group 14 element compounds such as silicon oxide (silica, silica gel), and glass; and natural mineral fine particles such as karnalite, kainite, mica, and byrrosite. The average particle size of the inorganic fine particles is not particularly limited, but 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 determined appropriately and may be, for example, 0.001 to 5 parts by mass or 0.005 to 3 parts by mass.

[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 modified polyolefins obtained by partially oxidizing vinyl acetate-ethylene copolymer polyolefins and / or modifying them with reactive functional groups such as maleic acid. Examples of polyolefins constituting the modified polyolefins modified with reactive functional groups 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, or hydrogenated versions of these.

[0057] <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 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.

[0058] <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 and a highly thermally conductive inorganic filler having a thermal conductivity of 20 W / m·K or more. Preferably, the method for producing the resin composition of this embodiment includes a step of mixing the 3-methyl-1-butene polymer with the highly thermally conductive inorganic filler having a thermal conductivity of 20 W / m·K or more. There are no particular limitations on the mixing method. More preferably, 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.

[0059] [Sheet] The sheet of this embodiment includes the resin composition of this embodiment. The sheet of this embodiment includes a 3-methyl-1-butene polymer and a highly thermally conductive inorganic filler having a thermal conductivity of 20 W / m·K or more. The sheet can be used for a variety of purposes, but is preferably used for heat-dissipating circuit boards. The sheet of this embodiment may consist only of the resin composition, or may include components other than the resin composition.

[0060] <Dielectric Loss Tangent of Sheet> The dielectric loss tangent of the sheet 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 sheet at 10 kHz to 300 GHz refers to a value measured by common techniques such as the capacitance method, the resonance method, and the frequency variation method. 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. When the measurement frequency is 1 GHz to 300 GHz, measurement is preferably performed by the resonance method or the frequency variation method. The dielectric loss tangent measured by the cavity resonance method at a measurement frequency of 10 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 measured by the frequency variation method at a measurement frequency of 100 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 measured by the frequency change method at a measurement frequency of 200 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 resin composition of this embodiment can be measured by common techniques such as the capacitance method, the resonance method, and the frequency change method. Specifically, the dielectric loss tangent of the resin composition of this embodiment can be determined by preparing a sheet from the resin composition and measuring the dielectric loss tangent of the sheet using the method described in the examples. The preferred range of the dielectric loss tangent of the resin composition is the same as described above.

[0061] <Dielectric Constant of Sheet> The dielectric constant of the sheet 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 an economical viewpoint, 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, 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 sheet 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 change method. 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 by the cavity resonance method at a measurement frequency of 10 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 by the frequency variation method at a measurement frequency of 100 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 by the frequency variation method at a measurement frequency of 200 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 resin composition of this embodiment can be measured by common techniques such as the capacitance method, the resonance method, and the frequency variation method. Specifically, the dielectric constant of the resin composition of the present embodiment can be determined by preparing a sheet from the resin composition and measuring the dielectric constant of the sheet by the method described in the Examples. The preferred range of the dielectric constant of the resin composition is the same as above.

[0062] <Thermal Conductivity of Sheet> The thermal conductivity of the sheet of this embodiment at 25°C is preferably 0.5 W / m·K or more, more preferably 0.6 W / m·K or more, more preferably 1.0 W / m·K or more, even more preferably 2.0 W / m·K or more, and even more preferably 5.0 W / m·K or more. When the thermal conductivity of the sheet is equal to or greater than the above lower limit, good heat dissipation properties are obtained when used as a circuit board material. The thermal conductivity can be adjusted by adjusting the type and content of the thermally conductive filler. The thermal conductivity of the sheet can be measured by the method described in the Examples. Specifically, the thermal conductivity of the resin composition of this embodiment can be determined by preparing a sheet from the resin composition and measuring the thermal conductivity of the sheet by the method described in the Examples. The preferred range of the thermal conductivity of the resin composition is the same as above.

[0063] <Sheet Manufacturing Method> The sheet manufacturing method of this embodiment is not particularly limited as long as it is a method for manufacturing the above-described sheet. From the viewpoint of obtaining a sheet having high thermal conductivity, a low dielectric constant, a low dielectric loss tangent, and capable of reflow soldering, the sheet manufacturing method preferably includes a step of obtaining a 3-methyl-1-butene polymer and a step of molding the resin composition to obtain a sheet. Furthermore, when obtaining a resin composition 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 a resin composition described below. In other words, the sheet manufacturing method more preferably includes a step of obtaining a 3-methyl-1-butene polymer, a step of obtaining a resin composition, and a step of molding the resin composition to obtain a sheet.

[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 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.

[0065] [Step of Obtaining Resin Composition] In this embodiment, 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 a highly thermally conductive inorganic filler having a thermal conductivity of 20 W / m·K or more. The resin composition is obtained by mixing the 3-methyl-1-butene polymer and the highly thermally conductive inorganic filler having a thermal conductivity of 20 W / m·K or more. The mixing method is not particularly limited, and a method of melt-kneading using a twin-screw kneading extruder or the like can be used. Furthermore, the raw materials may be dry-blended before melt-kneading. Examples of 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, in addition to the highly thermally conductive inorganic filler.

[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 sheet 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 Sheet] In this embodiment, the step of obtaining a sheet is a step of obtaining a sheet by molding a resin composition. The molding method is not particularly limited, and an appropriate method may be used depending on the shape of the sheet, etc. 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 the ability to obtain molded products with excellent dimensional accuracy.

[0074] <Sheet Shape> There are no particular limitations on the shape (dimensions) of the sheet. The thickness of the sheet may be 0.01 to 5.0 mm, 0.05 to 2.0 mm, or 0.1 to 1.0 mm.

[0075] [Metal Foil-Attached Substrate] The metal foil-attached substrate of this embodiment includes the sheet of this embodiment and a metal foil in contact with one surface of the sheet. The metal foil-attached substrate of this embodiment may further include a metal foil in contact with the other surface of the sheet. That is, the metal foil-attached substrate of this embodiment may include the sheet of this embodiment and a metal foil on both surfaces of the sheet. The metal foil may be made of any material, including copper foil, silver foil, gold foil, and aluminum foil. Copper foil is generally preferred from the standpoints of electrical conductivity, etchability, cost, and the like. The thickness of the metal foil may be 0.1 to 100 μm, 1 to 50 μm, or 10 to 50 μm. The metal foil-attached substrate of this embodiment may be manufactured by hot pressing a metal foil on each side of the sheet of this embodiment. The hot pressing conditions are also not particularly limited, and the pressing temperature may be 200 to 350°C or 250 to 350°C. Press pressure: 100 to 1,500 kgf / cm ２ and 200 to 1,000 kgf / cm ２ and 500 to 800 kgf / cm ２ may be.

[0076] [Circuit Board] The circuit board of this embodiment includes the sheet of this embodiment and a circuit in contact with one surface of the sheet. The circuit board of this embodiment may further include a metal foil in contact with the other surface of the sheet, or may include a circuit board in contact with the other surface of the sheet. More specifically, the circuit board of this embodiment may include the sheet of this embodiment, a circuit on one surface of the sheet, and a metal foil or another circuit board on the other surface of the sheet. There are no particular limitations on the manufacturing method for the circuit board of this embodiment, and it can be manufactured using a known method. For example, a circuit board can be manufactured by forming a circuit by removing a portion of the metal foil of the metal foil-coated substrate of this embodiment. The circuit board of this embodiment is preferably a heat-dissipating circuit board. A heat-dissipating circuit board is a circuit board in which the thermal conductivity of the sheet used at 25°C is preferably 0.5 W / m·K or more, more preferably 0.6 W / m·K or more, more preferably 1.0 W / m·K or more, even more preferably 2.0 W / m·K or more, and even more preferably 5.0 W / m·K. When the thermal conductivity of the sheet is equal to or greater than the above lower limit, good heat dissipation properties can be obtained when the sheet is used as a circuit board.

[0077] The present invention will be specifically explained below with reference to examples and comparative examples, but the present invention is not limited to these.

[0078] <Measurement and Evaluation Methods> Various physical properties were measured or evaluated by the following methods.

[0079] [Content of structural units derived from comonomers] The content of structural units derived from 1-decene (comonomer), an α-olefin other than 3-methyl-1-butene, in the 3-methyl-1-butene copolymers 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: Deformation vibration derived from the main chain methylene group of 3-methyl-1-butene homopolymer: 1,461 cm －１ and the bending vibration of 727 cm originating from the side chain methylene group of the homopolymer of α-olefin (1-decene).－１ A calibration curve was created from the ratio of the peak area of ​​each polymer (3-methyl-1-butene copolymer and α-olefin) to the peak area of ​​each polymer, and the addition ratio of each polymer (3-methyl-1-butene copolymer and α-olefin). The IR measurement was performed on the 3-methyl-1-butene copolymer obtained in Production Example, and the obtained 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).

[0080] [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.

[0081] [Melt Viscosity] The melt viscosity (Pa·s) of the polymers obtained in Production 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).

[0082] [Specific Gravity] The 3-methyl-1-butene polymers and resin compositions used in the examples and comparative examples were press-molded at a press temperature of 320°C and a press pressure of 1.8 MPa to prepare test specimens (length: 40 mm, width: 10 mm, thickness: 4 mm). The specific gravity of the test specimens was measured in accordance with Method A of JIS K 7112:1999.

[0083] [Dielectric Constant and Dielectric Loss Tangent] The resin compositions prepared in the examples and comparative examples 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). Using the test pieces, the dielectric constant 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 prepared in the examples and comparative examples were injection molded to prepare test pieces (length: 40 mm, width: 40 mm, thickness: 0.5 mm). Using the test pieces, 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). Furthermore, the resin compositions prepared in the examples and comparative examples were injection molded to prepare test specimens (length: 40 mm, width: 40 mm, thickness: 0.5 mm). The dielectric constant and dielectric loss tangent of the test specimens 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).

[0084] [Reflow Heat Resistance] The resin compositions prepared in the examples and comparative examples 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). The test pieces were left standing in an atmosphere of 85°C and 85% RH for 7 days. After leaving the test pieces standing, they 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 test pieces 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 above 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.

[0085] [Thermal Conductivity] Measurement samples were cut out to a size of 10 mm square from the 0.5 mm thick sheets prepared in the Examples and Comparative Examples. A thin layer of laser light absorbing spray ("Blackguard Spray FC-153" manufactured by Fine Chemical Japan Co., Ltd.) was applied to both sides of the samples and dried. Thereafter, the thermal diffusivity a (mm ) in the sheet thickness direction at a measurement temperature of 25°C was measured by laser flash method using a xenon flash analyzer ("LFA447 NanoFlash300" manufactured by NETZSCH). ２ / sec) was measured. The measurement was carried out on five points cut out from the same sheet, and the arithmetic average value was calculated. This arithmetic average value was used to calculate the thermal conductivity. From these measured values, the thermal conductivity H (W / m K) in the sheet thickness direction at 25 ° C. was calculated as "H = a × ρ × c". In this case, the specific heat c is a value obtained using a differential scanning calorimeter ("DSC25" manufactured by TA Instrument) in accordance with heat flux differential scanning calorimetry of JIS K 7123:1987. In addition, ρ is the value of specific gravity measured by the above method.

[0086] [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.

[0087] [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, the melt viscosity was 104 Pa s, and the specific gravity was 0.89. Furthermore, the content of structural units derived from the comonomer 1-decene in copolymer (A) was 1.1 mol%.

[0088] [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, the melt viscosity was 99 Pa s, and the specific gravity was 0.89. Furthermore, the content of structural units derived from the comonomer 1-decene in copolymer (B) was 6.4 mol%.

[0089] [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. The obtained homopolymer (C) was subjected to the above-mentioned measurements, and the melting point was 305°C, the melt viscosity was 126 Pa s, and the specific gravity was 0.89.

[0090] [Example 1] (Resin Composition) The components shown in Table 1 were dry-blended in the mixing ratios shown in Table 1, and then melt-kneaded using a small kneader "Micro 15 Compounder" (manufactured by DSMXplore) to obtain a pellet-shaped resin composition (M1). Details of the various components in Table 1 are as follows.

[0091] Copolymer (A): Copolymer produced according to Production Example 1 High thermal conductive inorganic filler 1: Boron nitride, trade name "Denka Boron Nitride SP-2" manufactured by Denka Company Limited (thermal conductivity 40 to 80 W / mK, specific gravity 2.30) High thermal conductive inorganic filler 2: Aluminum nitride, trade name "Aluminum Nitride (AIN) Powder" manufactured by Tokuyama Corporation (thermal conductivity 180 W / mK, specific gravity 3.26) High thermal conductive inorganic filler 3: Aluminum oxide, trade name "Aluminum Oxide Powder" manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. (thermal conductivity 28 W / mK, specific gravity 3.97) Phenol-based antioxidant (AO-60): Pentaerythritol tetrakis [3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], trade name "AO-60" manufactured by ADEKA Corporation Phosphorus-based antioxidant (PEP-36): 3,9-bis(2,6-di-t-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane, trade name "PEP-36", manufactured by ADEKA Corporation. Alkyl radical scavenger (Sumilizer (registered trademark) GS): acrylic phenol compound, 2,4-di-t-amyl-6-[1-(3,5-di-t-amyl-2-hydroxyphenyl)ethyl]phenyl acrylate, trade name "Sumilizer (registered trademark) GS", manufactured by Sumitomo Chemical Co., Ltd. Antacid (zinc stearate): zinc stearate.

[0092] The content (vol %) of the highly thermally conductive inorganic filler in the resin composition shown in Table 1 was calculated using the amounts of the 3-methyl-1-butene polymer and the highly thermally conductive inorganic filler added to the resin composition and the specific gravity values. Note that components other than the 3-methyl-1-butene polymer and the highly thermally conductive inorganic filler added to the resin composition were not taken into account in the calculation because their amounts were small.

[0093] (Sheet) The obtained resin composition (M1) was extrusion molded using an extrusion molding machine "twin-screw kneading extruder KZW15-45" (manufactured by Technovel Co., Ltd.) under a nitrogen atmosphere at a resin temperature of 320°C to obtain a sheet having a size of 80 mm square and a thickness of 0.5 mm.

[0094] (Metal Foil Substrate) After plasma treatment was performed on the surface of the obtained sheet, copper foils with a thickness of 35 μm were placed on both sides of the sheet, and the sheet was heated at 300° C. and 70 kgf / cm ２ The sheet was then hot pressed at 1000 kJ / min to prepare a copper-pressed sheet (metal foil substrate).

[0095] [Examples 2 to 7 and Comparative Example 1] Resin composition (M2) (Example 2), resin composition (M3) (Example 3), resin composition (M4) (Example 4), resin composition (M5) (Example 5), resin composition (M6) (Example 6), resin composition (M7) (Example 7), and resin composition (M8) (Comparative Example 1) were obtained in the same manner as in Example 1, except that the types and amounts of components were as shown in Table 1. Next, sheets and copper-bonded sheets (metal foil substrates) were produced and evaluated in the same manner as in Example 1, except that resin compositions (M2) to (M8) were used instead of resin composition (M1). The results are shown in Table 1.

[0096]

[0097] As shown in the examples, a sheet containing a resin composition containing a 3-methyl-1-butene polymer of this embodiment has high thermal conductivity, a low dielectric constant and a low dielectric loss tangent, and is reflow solderable. Therefore, the sheet of this embodiment is highly useful industrially.

Claims

1. A resin composition comprising a 3-methyl-1-butene polymer and a highly thermally conductive inorganic filler having a thermal conductivity of 20 W / m·K or more.

2. The resin composition 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 is an α-olefin having 3 to 20 carbon atoms.

3. The resin composition according to claim 2, 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.

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

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

6. 2. The resin composition according to claim 1, wherein the content of the highly thermally conductive inorganic filler is 10 to 95% by volume.

7. 2. The resin composition according to claim 1, wherein the highly thermally conductive inorganic filler is at least one selected from the group consisting of boron nitride, aluminum nitride, and aluminum oxide.

8. The resin composition according to claim 1 , wherein the highly thermally conductive inorganic filler is boron nitride.

9. The resin composition according to claim 1, wherein the content of the structural units derived from 3-methyl-1-butene in 100 mol% of the copolymer is more than 50 mol%.

10. A sheet comprising the resin composition according to any one of claims 1 to 9.

11. The sheet according to claim 10, which is for use in a heat-dissipating circuit board.

12. A metal foil-coated substrate comprising the sheet of claim 10.

13. A circuit board comprising the sheet of claim 10.

14. A method for producing a resin composition, comprising producing a resin composition containing a 3-methyl-1-butene polymer and a highly thermally conductive inorganic filler having a thermal conductivity of 20 W / m·K or more.