Laminate

Abstract

To provide a laminate capable of obtaining a thin molded body containing a nitride-containing olefin-based resin composition.SOLUTION: There is provided a laminate obtained by laminating a polar resin layer, a release layer and an olefin-based resin composition layer in this order, wherein at least one surface of the polar resin layer has an embossed pattern, the release layer is adjacent to the surface of the polar resin layer having the embossed pattern, the olefin-based resin composition layer contains an ethylene-α-olefin copolymer (A1), an acid-modified ethylene-α-olefin copolymer (A2), an ethylene-propylene copolymer (B) and a nitride (C), the copolymer (A1) and the copolymer (A2) satisfy specific requirements and the content of the copolymer (A1) to the total content of the copolymer (A1) and the copolymer (A2), the content of the copolymer (B), the content of the nitride (C) and the content of the copolymer (A2) is within a specified range.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a laminate.

Background Art

[0002] In recent years, the high functionality and miniaturization of electronic devices have advanced, and the density of electronic components has increased. For this reason, for the purpose of ensuring the normal operation and lifespan of electronic devices and electronic components, controlling the heat generated from these has become a major issue. As one of the countermeasures against this issue, a technique for releasing heat to the outside of electronic devices and electronic components has been developed, and many electronic devices incorporate heat dissipation members such as heat sinks, heat spreaders, heat pipes, and cooling fans. In addition, some small devices such as mobile phones are designed to function as heat dissipation members themselves and release heat to the outside. In these electronic devices, a member called Thermal Interface Material (hereinafter also referred to as "TIM") is used for the purpose of improving the thermal conductivity between the heat generating body and the heat dissipation member and between the heat dissipation members.

[0003] TIM is roughly composed of two components. One is a filler that ensures heat conduction. For this, metal oxides, metal nitrides, metal hydroxides, metal carbides, and metal powders with high thermal conductivity are used. The other component is a binder that holds the filler and keeps the TIM in a predetermined shape. The binder varies greatly depending on the type of TIM, and various organic materials such as curable resins such as silicone and acrylic, thermoplastic resins, elastomers, oils, and waxes are used.

[0004] Among these, as the binder, silicone-based compounds are often used from the viewpoint of the heat resistance stability of the TIM itself. For example, Patent Document 1 discloses a heat dissipation grease containing aluminum nitride, zinc oxide, and silicone oil.

[0005] However, in the case of silicone-based compounds, low-molecular-weight siloxanes contained therein or gradually decomposed and generated from silicone-based compounds may deposit on an electronic circuit as insulating foreign matters such as silicon dioxide, causing contact failure. Therefore, the development of non-silicone-based TIMs has been actively carried out. As such non-silicone-based TIMs, for example, the thermally conductive compositions described in Patent Documents 2 and 3 are known.

[0006] Patent Document 4 discloses a resin composition containing one or more selected from graft-modified products of α-olefin (co)polymers and α-olefin (co)polymers satisfying specific requirements, and one or more selected from olefin resins, styrene-based thermoplastic elastomers, and waxes, and discloses that the resin composition can be used as TIM.

[0007] As a method for forming a thermally conductive composition or the resin composition into a sheet for use as TIM, for example, a method is known in which the thermally conductive composition or the resin composition is sandwiched between two release sheets, and a laminate in which the release sheet and the sheet containing the thermally conductive composition or the resin composition are laminated is manufactured by hot pressing and cooling pressing, and then the sheet is peeled from the release sheet.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0009] However, when attempting to thin a thermally conductive composition containing a nitride such as a metal nitride as a filler or a sheet formed from the resin composition, in the above-described manufacturing method, when peeling the sheet from the protective sheet, the sheet may tear, or the protective sheet may be compatible with the thermally conductive composition or the resin composition, and thus a sheet containing the thermally conductive composition or the resin composition may not be obtained in the first place.

[0010] The present invention has been made in view of the above circumstances, and an object thereof is to provide a laminate capable of obtaining a thin molded body containing a nitride-containing olefin resin composition.

Means for Solving the Problems

[0011] The present inventors have intensively studied to solve the above problems. As a result, according to the following configuration examples, it has been found that the above problems can be solved, and the present invention has been completed. The configuration examples of the present invention are as follows.

[0012] [1] A polar resin layer, a release layer, and an olefin resin composition layer are laminated in this order, At least one surface of the polar resin layer has an emboss pattern, The release layer is adjacent to the surface of the polar resin layer having the emboss pattern, The olefin resin composition layer contains an ethylene·α-olefin copolymer (A1), an acid-modified ethylene·α-olefin copolymer (A2), an ethylene·propylene copolymer (B), and a nitride (C), The ethylene·α-olefin copolymer (A1) satisfies the following requirements (A1-1) to (A1-4), The acid-modified ethylene·α-olefin copolymer (A2) satisfies the following requirements (A2-1) to (A2-2), With respect to a total of 100 parts by mass of the ethylene·α-olefin copolymer (A1), the acid-modified ethylene·α-olefin copolymer (A2), and the ethylene·propylene copolymer (B), the total content of the ethylene·α-olefin copolymer (A1) and the acid-modified ethylene·α-olefin copolymer (A2) is 21 to 79 parts by mass, the content of the ethylene·propylene copolymer (B) is 21 to 79 parts by mass, and the content of the nitride (C) is 1200 to 1500 parts by mass. The mass ratio of the content of the ethylene·α-olefin copolymer (A1) to the content of the acid-modified ethylene·α-olefin copolymer (A2) [content of copolymer (A1) / content of copolymer (A2)] is 99 / 1 to 1 / 99. Laminate; Requirement (A1-1): The ethylene·α-olefin copolymer (A1) contains a structural unit (i) derived from ethylene and a structural unit (ii) derived from an α-olefin having 4 to 20 carbon atoms. Requirement (A1-2): The melt flow rate (MFR) measured under the conditions of 190°C and a load of 2.16 kg in accordance with ASTM D1238 is 5 to 100 g / 10 min. Requirement (A1-3): The Shore A hardness 15 seconds after the start of the needle pressing contact in a sample obtained by stacking 7 crosslinked sheets each having a thickness of 1 mm and measured in accordance with ASTM D2240 is 75 to 99. Requirement (A1-4): The ethylene·α-olefin copolymer (A1) is unmodified. Requirement (A2-1): The acid-modified ethylene·α-olefin copolymer (A2) is obtained by modifying an ethylene·α-olefin copolymer containing a structural unit (i) derived from ethylene and a structural unit (ii) derived from an α-olefin having 4 to 20 carbon atoms with an unsaturated carboxylic acid or its derivative. Requirement (A2-2): The MFR measured under the conditions of 190°C and a load of 2.16 kg in accordance with ASTM D1238 is 5 to 100 g / 10 min.

[0013] [2] The laminate according to [1], wherein the polar resin layer contains a polyester resin.

[0014] [3] The laminate according to [1] or [2], wherein the embossed pattern is diamond-shaped. [Advantages of the Invention]

[0015] According to the present invention, it is possible to provide a laminate capable of obtaining a thin molded body containing a nitride-containing olefin resin composition. [Embodiments for Carrying Out the Invention]

[0016] Hereinafter, the present invention will be specifically described. In this specification, the symbol "~" indicating a numerical range means "M or more and N or less" in the case of "M~N", unless otherwise specified. In this specification, the term "(co)polymer" is used as a concept including both homopolymers and copolymers. In this specification, when an olefin constituting a certain (co)polymer is denoted as M, the expression "structural unit derived from M" may be used, which means "structural unit corresponding to M", that is, a structural unit having a pair of bonds formed by opening the π bond constituting the double bond of M. In this specification, a sheet is not particularly distinguished from a film or the like, and a film (plate)-shaped molded body is generically referred to as a sheet.

[0017] [Laminate] The laminate according to the present invention is a laminate in which a polar resin layer, a release layer, and an olefin resin composition layer are laminated in this order, and the olefin resin composition layer contains an ethylene-α-olefin copolymer (A1), an acid-modified ethylene-α-olefin copolymer (A2), an ethylene-propylene copolymer (B), and a nitride (C). The olefin resin composition forming the olefin resin composition layer is also referred to as an "olefin resin composition".

[0018] For example, after forming the laminate into a sheet using a press or the like, the olefin resin composition layer is crosslinked, and then the crosslinked olefin resin composition layer is peeled off from the polar resin layer and the release layer to obtain a sheet-like crosslinked body (crosslinked sheet). The crosslinked sheet can be used, for example, as a TIM.

[0019] The thermal conductivity of the crosslinked body (crosslinked sheet) measured by the temperature gradient method (ASTM D5470-1, thickness: 1 mm, pressure: 0.3 MPa) is preferably 3.5 W / m·K or more, more preferably 3.7 W / m·K or more, and still more preferably 4.0 W / m·K or more. The upper limit of the thermal conductivity measured by the temperature gradient method is not particularly limited, and the larger the better. For example, it is 5.0 W / m·K. The thermal conductivity of the crosslinked body (crosslinked sheet) measured by the periodic heating method (ISO22007-3, thickness: 200 μm or less) is preferably 7.0 W / m·K or more, more preferably 7.3 W / m·K or more, and still more preferably 7.6 W / m·K or more. The upper limit of the thermal conductivity measured by the periodic heating method is not particularly limited, and the larger the better. For example, it is 10.0 W / m·K. It can be said that a crosslinked body having a thermal conductivity within the above range is excellent in thermal conductivity. Specifically, the thermal conductivity is measured by the method described in the column of the following examples.

[0020] The volume resistivity of the crosslinked body (crosslinked sheet) is preferably 1.0×10 14 Ω·cm or more, more preferably 3.0×10 14 Ω·cm or more, and still more preferably 5.0×10 14 Ω·cm or more. The upper limit of the volume resistivity is, for example, 1.0×10 15 Ω·cm. It can be said that a crosslinked body having a volume resistivity within the above range is excellent in electrical insulation. Specifically, the volume resistivity is measured by the method described in the column of the following examples.

[0021] The dielectric breakdown strength of the crosslinked body (crosslinked sheet) is preferably 30 kV / mm or more, more preferably 35 kV / mm or more, and still more preferably 40 kV / mm or more. The upper limit of the dielectric breakdown strength is, for example, 60 kV / mm. The crosslinked body with the dielectric breakdown strength within the above range can be used even under high voltage conditions. Specifically, the dielectric breakdown strength is measured by the method described in the column of the following examples.

[0022] Using RSA-III (manufactured by TA Instruments) as a solid viscoelasticity measuring device for the crosslinked body (crosslinked sheet), the upper limit value of the temperature range with a continuous rubber plateau region measured under a deformation mode: tension, frequency: 1 Hz, temperature range: -50 to 240 °C, heating rate: 3 °C / min, and nitrogen atmosphere is preferably 240 °C or more. It can be said that the crosslinked body with the upper limit value of the above temperature range of 240 °C or more has excellent heat resistance.

[0023] ≪Polar resin layer≫ The laminate includes a polar resin layer. Since the laminate includes a polar resin layer, a thin molded body containing the olefin resin composition can be easily obtained from the laminate.

[0024] Examples of the polar resin forming the polar resin layer include polyester resin, polyamide resin, polyimide resin, polystyrene resin, acrylic resin, vinyl chloride resin, polycarbonate resin, ABS resin, urethane resin, melamine resin, polyvinyl alcohol resin, epoxy resin, and polyphenylene ether resin.

[0025] Examples of the polyester resin include polyethylene terephthalate resin, polybutylene terephthalate resin, and polyethylene naphthalate resin. Examples of the polyamide resin include polyamide 6, polyamide 66, polyamide 11, polyamide 12, polyamide 612, polyamide 610, and polyamide 1010.

[0026] Examples of the polyimide resin include aromatic polyimide resins and alicyclic polyimide resins. Further examples of the polyimide resin include polyamideimide resins, polyetherimide resins, and fluorinated polyimide resins.

[0027] Examples of the acrylic resin include acrylic resins having vinyl compounds such as acrylic acid, methacrylic acid ester, methacrylamide, and methacrylonitrile as monomers.

[0028] The polar resin layer preferably contains a polyester resin or a polyimide resin, more preferably contains a polyester resin, and even more preferably contains a polyethylene terephthalate resin. When the polar resin layer contains these resins, a thin molded body containing the olefin resin composition can be easily obtained from the laminate. The polar resin layer may contain only one kind of polar resin or may contain two or more kinds.

[0029] At least one surface of the polar resin layer has an embossed pattern. Examples of the embossed pattern include a matte finish, a silk texture, a cloth texture, a homespun pattern, a wavy pattern, a diamond pattern, a lattice pattern, a checkered pattern, and a vine pattern. The embossed pattern is preferably a silk texture, a cloth texture, or a diamond pattern, and more preferably a diamond pattern. When at least one surface of the polar resin layer has an embossed pattern, a thin molded body containing the olefin resin composition can be easily obtained from the laminate. Further, when at least one surface of the polar resin layer has an embossed pattern, when the olefin resin composition layer is crosslinked by electron beam irradiation, the hydrogen gas generated by the electron beam irradiation easily escapes from the laminate, so that a hydrogen gas escape trace is less likely to remain in the olefin resin composition layer. The size of the repeating unit of the embossed pattern is preferably a size that fits within a square with a side length of 0.2 to 5 mm, and more preferably a size that fits within a square with a side length of 0.3 to 4 mm.

[0030] <<Release layer>> The laminate includes a release layer. The release layer is a layer containing a release agent. Since the laminate includes a release layer, a thin molded article containing the olefin resin composition can be easily obtained from the laminate.

[0031] Examples of the release agent include silicone-based release agents such as silicone oil, wax-based release agents such as polyolefin wax, and fluorine-based release agents. The silicone oil may be a reactive silicone oil or a non-reactive silicone oil.

[0032] The reactive silicone oil refers to a modified silicone oil having an organic group introduced into the side chain or terminal, and having reactivity depending on the nature of the introduced organic group. Examples of the reactive silicone oil include those in which the introduced organic group is an amino group, an epoxy group, a mercapto group, a carboxy group, a carbinol group, a phenol group, an acrylic group, a methacrylic group, or a hetero-functional group in modified silicone oil side chain type, modified silicone oil both ends type, modified silicone oil one end type, and modified silicone oil side chain both ends type. The reactive silicone oil may be used alone or in combination of two or more.

[0033] The non-reactive silicone oil is a silicone oil having no reactive functional groups such as an amino group, an epoxy group, a mercapto group, a carboxy group, a hydroxy group, a (meth)acrylic group, and an allyl group. Examples of the non-reactive silicone oil include silicone oil made of polysiloxane, polyether-modified silicone oil, aralkyl-modified silicone oil, fluoroalkyl-modified silicone oil, long-chain alkyl-modified silicone oil, higher fatty acid ester-modified silicone oil, higher fatty acid amide-modified silicone oil, and phenyl-modified silicone oil. The non-reactive silicone oil may be used alone or in combination of two or more.

[0034] The release agent is preferably a silicone-based release agent. When the release agent is a silicone-based release agent, a thin molded body containing the olefin resin composition can be easily obtained from the laminate.

[0035] The release layer is adjacent to the surface having the embossed pattern in the polar resin layer. When the release layer is adjacent to the surface having the embossed pattern in the polar resin layer, a thin molded body containing the olefin resin composition can be easily obtained from the laminate.

[0036] The total thickness of the polar resin layer and the release layer is preferably 25 to 100 μm, more preferably 30 to 90 μm, and even more preferably 35 to 80 μm.

[0037] As the polar resin layer and the release layer, a commercially available release sheet in which a release agent is applied to a base sheet made of a polar resin having an embossed pattern may be used. Examples of commercially available products of base sheets made of polyester resin include the "Diafoil" series (manufactured by Mitsubishi Chemical Corporation), the "NOACRYSTAL" series (manufactured by RP-Toray Co., Ltd.), and the "Kaneron" series (manufactured by Shinei Kasei Co., Ltd.). Examples of commercially available products of base sheets made of polyimide resin include the "Apical" series (manufactured by Kaneka Corporation), the "Kapton" series (manufactured by Toray DuPont Co., Ltd.), and the "Upilex" series (manufactured by Ube Industries, Ltd.). For example, when the base sheet is a polyethylene sheet or a polypropylene sheet, the olefin resin composition layer and the base sheet may be compatible, and a sheet containing the olefin resin composition may not be obtained.

[0038] ≪Olefin Resin Composition Layer≫ The laminate includes an olefin resin composition layer. The olefin resin composition layer contains an ethylene·α-olefin copolymer (A1), an acid-modified ethylene·α-olefin copolymer (A2), an ethylene·propylene copolymer (B), and a nitride (C).

[0039] <Ethylene·α-olefin copolymer (A1)> The ethylene·α-olefin copolymer (A1) satisfies the following requirements (A1-1) to (A1-4). The ethylene·α-olefin copolymer (A1) is also referred to as "copolymer (A1)". The copolymer (A1) may be one kind or two or more kinds.

[0040] Requirement (A1-1): The ethylene·α-olefin copolymer (A1) contains a structural unit (i) derived from ethylene and a structural unit (ii) derived from an α-olefin having 4 to 20 carbon atoms. As the copolymer (A1), a copolymer composed only of the structural unit (i) and the structural unit (ii) is preferable.

[0041] The content (ethylene content) of the structural unit (i) in the copolymer (A1) is not particularly limited, but is preferably 51 to 99 mol%, more preferably 60 to 98 mol%, based on 100 mol% in total of the structural unit (i) and the structural unit (ii).

[0042] Examples of the α-olefin having 4 to 20 carbon atoms that leads to the structural unit (ii) include 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicosene. As the α-olefin that leads to the structural unit (ii), an α-olefin having 4 to 8 carbon atoms is preferable, 1-butene and 1-octene are more preferable, and 1-butene is even more preferable in terms of, for example, the resulting molded article and crosslinked body having excellent balance in tensile elongation at break, hardness (Shore A hardness), and thermal conductivity. That is, it is even more preferable that the copolymer (A1) is an ethylene·1-butene copolymer. The copolymer (A1) preferably does not contain a structural unit derived from propylene.

[0043] As the ethylene that leads to the structural unit (i) and the α-olefin that leads to the structural unit (ii), those derived from biomass, those derived from fossil fuels, or both a biomass-derived monomer and a fossil fuel-derived monomer may be used. The α-olefin used as a raw material for the copolymer (A1) may be one kind or two or more kinds.

[0044] Requirement (A1-2) The melt flow rate (MFR) measured under the conditions of 190 °C and a load of 2.16 kg in accordance with ASTM D1238 is 5 to 100 g / 10 min. The MFR is preferably 7 to 100 g / 10 min, more preferably 10 to 75 g / 10 min, and still more preferably 13 to 60 g / 10 min. The copolymer (A1) having an MFR within the above range is easy to mix with the nitride (C), and when kneaded with the nitride (C), the fluidity hardly decreases and it hardly becomes hard. When the MFR of the copolymer (A1) is equal to or higher than the lower limit value, a decrease in the fluidity of the olefin resin composition can be suppressed, and a thin molded body containing the olefin resin composition can be easily obtained from the laminate. When the MFR of the copolymer (A1) is equal to or lower than the upper limit value, the olefin resin composition has appropriate fluidity, and the laminate can be easily produced.

[0045] Requirement (A1-3) The Shore A hardness 15 seconds after the start of the indentation needle contact in a sample in which 7 cross-linked sheets with a thickness of 1 mm are stacked, measured in accordance with ASTM D2240, is 75 to 99. The Shore A hardness is 75 to 99, preferably 78 to 95, and more preferably 81 to 90. The Shore A hardness of the copolymer (A1) can be adjusted, for example, by controlling the content of the structural unit (i) derived from ethylene. That is, the copolymer (A1) with a large content of the structural unit (i) has a high Shore A hardness. On the other hand, the copolymer (A1) with a small content of the structural unit (i) has a low Shore A hardness.

[0046] By using the copolymer (A1) having a Shore A hardness within the above range, a crosslinked product (crosslinked sheet) excellent in flexibility can be easily obtained. When the crosslinked product is excellent in flexibility, the crosslinked product can adhere to a heating element and a heat dissipation member, etc. (because it has excellent followability to the unevenness on the surface of the heating element and the heat dissipation member, etc.), and the heat from the heating element can be efficiently transmitted to the heat dissipation member. Therefore, the crosslinked product can be particularly preferably used as a TIM. Further, when the Shore A hardness of the copolymer (A1) is equal to or higher than the lower limit value, a thin molded body containing the olefin resin composition can be easily obtained from the laminate.

[0047] Requirement (A1-4) The ethylene-α-olefin copolymer (A1) is unmodified.

[0048] The density of the copolymer (A1) measured in accordance with ASTM D1505 is preferably 850 to 910 kg / m 3 , more preferably 860 to 900 kg / m 3 , still more preferably 863 to 890 kg / m 3 is. The melting point of the copolymer (A1) measured by a differential scanning calorimeter (DSC) under the following conditions is preferably 30 to 120°C, more preferably 40 to 100°C, still more preferably 50 to 80°C.

[0049] 〈Measurement conditions for melting point〉 Using a differential scanning calorimeter, about 5.0 mg of a sample is heated from 30°C to 200°C at a heating rate of 10°C / min in a nitrogen atmosphere and held at that temperature for 10 minutes. Further, it is cooled to -10°C at a cooling rate of 10°C / min, held at that temperature for 5 minutes, and then heated to 200°C at a heating rate of 10°C / min. The endothermic peak observed during this second heating is defined as the melting peak, and the temperature at which the melting peak appears is defined as the melting point. When the melting peak is multimodal, the temperature at which the melting peak on the highest temperature side appears is defined as the melting point.

[0050] The tensile elongation at break of the copolymer (A1) measured in accordance with ASTM D638 is preferably 500% or more, more preferably 600% or more, still more preferably 700% or more, and the upper limit is, for example, 1200% or less, in terms of the resulting molded article and crosslinked article being less likely to be hard and brittle.

[0051] As the copolymer (A1), a copolymer produced by a conventionally known method or a commercially available product may be used.

[0052] <Acid-modified ethylene·α-olefin copolymer (A2)> The acid-modified ethylene·α-olefin copolymer (A2) satisfies the following requirements (A2-1) to (A2-2). The acid-modified ethylene·α-olefin copolymer (A2) is also referred to as "copolymer (A2)". By including the copolymer (A2) in the olefin resin composition layer, a thin molded article containing the olefin resin composition can be easily obtained from the laminate. The copolymer (A2) may be one kind or two or more kinds.

[0053] Requirement (A2-1): The acid-modified ethylene·α-olefin copolymer (A2) is obtained by modifying an ethylene·α-olefin copolymer containing a structural unit (i) derived from ethylene and a structural unit (ii) derived from an α-olefin having 4 to 20 carbon atoms with an unsaturated carboxylic acid or a derivative thereof. The unmodified ethylene-α-olefin copolymer before being modified with an unsaturated carboxylic acid or its derivative is also referred to as "copolymer (a2)". The copolymer (a2) is preferably an ethylene-α-olefin copolymer consisting only of the constitutional unit (i) and the constitutional unit (ii). The copolymer (a2) preferably does not contain a constitutional unit derived from propylene.

[0054] The content of the constitutional unit (i) (ethylene content) in the copolymer (a2) is preferably 51 to 99 mol%, more preferably 60 to 98 mol%, based on 100 mol% in total of the constitutional unit (i) and the constitutional unit (ii).

[0055] Examples of the α-olefin having 4 to 20 carbon atoms that leads to the constitutional unit (ii) in the copolymer (a2) include 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicosene. As the α-olefin that leads to the constitutional unit (ii) in the copolymer (a2), an α-olefin having 4 to 8 carbon atoms is preferable, 1-butene and 1-octene are more preferable, and 1-butene is even more preferable. That is, the copolymer (a2) is more preferably an ethylene-1-butene copolymer. As the copolymer (a2), the copolymer (A1) may be used.

[0056] As the ethylene that leads to the constitutional unit (i) and the α-olefin that leads to the constitutional unit (ii) in the copolymer (a2), those derived from biomass may be used, those derived from fossil fuels may be used, or both a biomass-derived monomer and a fossil fuel-derived monomer may be used. The α-olefin used as a raw material of the copolymer (a2) may be one kind or two or more kinds.

[0057] Examples of the unsaturated carboxylic acid for modifying the copolymer (a2) include acrylic acid, methacrylic acid, maleic acid, fumaric acid, and itaconic acid. Examples of the derivative of the unsaturated carboxylic acid include acid anhydrides such as maleic anhydride, endic anhydride (cis-5-norbornene-endo-2,3-dicarboxylic anhydride), itaconic anhydride, and citraconic anhydride; esters such as methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, glycidyl acrylate, monoethyl maleate, diethyl maleate, monomethyl fumarate, dimethyl fumarate, monomethyl itaconate, and diethyl itaconate; amides such as acrylamide, methacrylamide, maleic monoamide, maleic diamide, maleic - N - monoethylamide, maleic - N,N - diethylamide, maleic - N - monobutylamide, maleic - N,N - dibutylamide, fumaric monoamide, fumaric diamide, fumaric - N - monobutylamide, and fumaric - N,N - dibutylamide; imides such as maleimide, N - butyl maleimide, and N - phenyl maleimide; metal salts such as sodium acrylate, sodium methacrylate, potassium acrylate, and potassium methacrylate. Among the unsaturated carboxylic acid and its derivatives, maleic acid and maleic anhydride are preferred, and maleic anhydride is more preferred.

[0058] The unsaturated carboxylic acid or its derivative for modifying the copolymer (a2) may be derived from biomass, may be derived from fossil fuel, or may use both biomass - derived monomer and fossil - fuel - derived monomer.

[0059] The modification of the copolymer (a2) with an unsaturated carboxylic acid or its derivative can be carried out by a conventionally known method. For example, an additive described below is added to the copolymer (a2) as necessary, and an unsaturated carboxylic acid or its derivative (for example, maleic acid or its anhydride) is graft-polymerized in the presence of a radical initiator to obtain a copolymer (A2).

[0060] The charged amount of the unsaturated carboxylic acid or its derivative is usually 0.010 to 15 parts by mass, preferably 0.010 to 5.0 parts by mass, based on 100 parts by mass of the copolymer (a2). The amount of the radical initiator used is usually 0.0010 to 1.0 parts by mass, preferably 0.0010 to 0.30 parts by mass, based on 100 parts by mass of the copolymer (a2).

[0061] Examples of the radical initiator include organic peroxides, azo compounds, and metal hydrides. The radical initiator may be used by mixing it as it is with the copolymer (a2), the unsaturated carboxylic acid or its derivative, and other optional components, or it may be used after dissolving it in a small amount of an organic solvent. This organic solvent is not particularly limited as long as it can dissolve the radical initiator.

[0062] The graft polymerization can be carried out by a conventionally known method. As the method, for example, the copolymer (a2) is dissolved in an organic solvent, an unsaturated carboxylic acid or its derivative, a radical initiator, etc. are added to the obtained solution, and the reaction is carried out at a temperature of 70 to 200°C, preferably 80 to 190°C, for 0.5 to 15 hours, preferably 1 to 10 hours.

[0063] Also, in a device such as an extruder, an acid-modified ethylene·α-olefin copolymer (A2) may be produced by reacting an unsaturated carboxylic acid or its derivative with the copolymer (a2) in the presence of a radical initiator without using a solvent. This reaction is usually carried out at a temperature equal to or higher than the melting point of the copolymer (a2) for usually 0.5 to 10 minutes.

[0064] The acid modification degree (hereinafter also referred to as "graft amount") of the acid-modified ethylene-α-olefin copolymer (A2) defined by the following formula is usually 0.45 to 20% by mass, preferably 0.50 to 10% by mass, more preferably 0.55 to 3% by mass. Acid modification degree (graft amount) (% by mass) = (mass of the structural unit having a structure derived from the monomer having an ethylenically unsaturated group and a polar functional group in one molecule) / (mass of the acid-modified ethylene-α-olefin copolymer (A2)) × 100 The acid modification degree can be calculated, for example, by hot pressing the acid-modified ethylene-α-olefin copolymer (A2) at 250 °C to produce a sheet, subjecting this sheet to FT-IR measurement, and based on the peak intensity at a wave number of 1780 cm -1 attributed to the carbonyl group and a separately prepared calibration curve.

[0065] The copolymer (A2) satisfies the following requirement (A2-2). Requirement (A2-2) The MFR measured under the conditions of 190 °C and a load of 2.16 kg in accordance with ASTM D1238 is 5 to 100 g / 10 min. The MFR is preferably 10 to 100 g / 10 min, more preferably 15 to 75 g / 10 min, still more preferably 20 to 60 g / 10 min. The copolymer (A2) having an MFR within the above range is easy to mix with the nitride (C), and when kneaded with the nitride (C), its fluidity hardly decreases and it hardly becomes hard. When the MFR of the copolymer (A2) is not less than the above lower limit value, a thin molded article containing the olefin resin composition can be easily obtained from the laminate. When the MFR of the copolymer (A2) is not more than the above upper limit value, the olefin resin composition has appropriate fluidity and the laminate can be easily produced.

[0066] The density of the copolymer (A2) measured in accordance with ASTM D1505 is preferably 850 to 910 kg / m 3 , more preferably 860 to 900 kg / m 3 , still more preferably 863 to 890 kg / m 3 is. The melting point of the copolymer (A2) measured by DSC under the above conditions is preferably 30 to 100 °C, more preferably 35 to 85 °C, and still more preferably 40 to 70 °C.

[0067] In the copolymer (A2), the Shore A hardness 15 seconds after the start of the needle pressing contact in a sample in which seven crosslinked sheets with a thickness of 1 mm are stacked in accordance with ASTM D2240 is preferably 20 to 99, more preferably 25 to 95, and still more preferably 30 to 90. By using the copolymer (A2) having a Shore A hardness within the above range, a crosslinked body (crosslinked sheet) excellent in flexibility can be easily obtained. When the crosslinked body is excellent in flexibility, the crosslinked body can adhere to a heating element and a heat radiating member, etc. (because it has excellent followability to the unevenness on the surface of the heating element and the heat radiating member, etc.), and the heat from the heating element can be efficiently transmitted to the heat radiating member. Therefore, the crosslinked body can be particularly preferably used as a TIM. The Shore A hardness of the copolymer (A2) can be adjusted, for example, by controlling the content of the structural unit (i) derived from ethylene in the unmodified copolymer (a2) before modification with an unsaturated carboxylic acid or its derivative.

[0068] In the olefin resin composition layer, with respect to a total of 100 parts by mass of the ethylene-α-olefin copolymer (A1), the acid-modified ethylene-α-olefin copolymer (A2), and the ethylene-propylene copolymer (B) described later, the total content of the ethylene-α-olefin copolymer (A1) and the acid-modified ethylene-α-olefin copolymer (A2) is 21 to 79 parts by mass, preferably 30 to 77 parts by mass, and still more preferably 35 to 75 parts by mass. When the total content of the copolymer (A1) and the copolymer (A2) is at or below the above upper limit value, when producing the olefin resin composition by kneading the copolymer (A1), the copolymer (A2), the copolymer (B), and the nitride (C), the surface of the kneading apparatus is less likely to be damaged. When the total content of the copolymer (A1) and the copolymer (A2) is at least the lower limit value, a thin molded article containing the olefin resin composition can be easily obtained from the laminate.

[0069] The mass ratio [content of copolymer (A1) / content of copolymer (A2)] of the content of the ethylene·α-olefin copolymer (A1) to the content of the acid-modified ethylene·α-olefin copolymer (A2) is 99 / 1 to 1 / 99, preferably 99 / 1 to 5 / 95, more preferably 98 / 2 to 7 / 93, and still more preferably 98 / 2 to 10 / 90. When the mass ratio of the content of the copolymer (A1) to the content of the copolymer (A2) is at most the upper limit value, interfacial delamination between the nitride (C) and the copolymer (A1) and the copolymer (A2) can be suppressed, and a thin molded article containing the olefin resin composition can be easily obtained from the laminate. When the mass ratio of the content of the copolymer (A1) to the content of the copolymer (A2) is at least the lower limit value, an increase in the hardness of the olefin resin composition can be suppressed, and when the copolymer (A1), the copolymer (A2), the copolymer (B), and the nitride (C) are kneaded to produce the olefin resin composition, the surface of the kneading device is less likely to be damaged.

[0070] <Ethylene·propylene copolymer (B)> The olefin resin composition layer contains an ethylene·propylene copolymer (B). By the olefin resin composition layer containing the ethylene·propylene copolymer (B), the olefin resin composition, the molded article, and the crosslinked body having higher thermal conductivity can be easily obtained. The ethylene·propylene copolymer (B) is also referred to as "copolymer (B)". The copolymer (B) may be one kind or two or more kinds.

[0071] The ethylene·propylene copolymer (B) contains a structural unit (I) derived from ethylene and a structural unit (II) derived from propylene. The content (ethylene content) of the structural unit (I) in the ethylene-propylene copolymer (B) is not particularly limited, but is preferably 20 to 80 mol%, more preferably 30 to 70 mol%, still more preferably 40 to 60 mol% based on 100 mol% of the total of the structural unit (I) and the structural unit (II).

[0072] Ethylene and propylene may be derived from biomass, may be derived from fossil fuels, or both biomass-derived monomers and fossil fuel-derived monomers may be used.

[0073] In one embodiment, the copolymer (B) is liquid at 25°C and 1 atm, preferably contains an ethylene-propylene copolymer that satisfies the following requirement (B-1), and more preferably the copolymer (B) satisfies the following requirement (B-1). Requirement (B-1) The Brookfield viscosity measured at 25°C is 100,000 to 300,000 mPa·s. The Brookfield viscosity (BF viscosity) is preferably 120,000 to 280,000 mPa·s, more preferably 140,000 to 260,000 mPa·s, still more preferably 160,000 to 240,000 mPa·s. By using the copolymer (B) in which the BF viscosity is equal to or higher than the lower limit value, the olefin resin composition, molded article, and crosslinked body having excellent handleability and less stickiness when adding and kneading the raw materials of the olefin resin composition can be easily obtained. Further, by using the copolymer (B) in which the BF viscosity is equal to or lower than the upper limit value, the viscosity is not too high when kneading the raw materials of the olefin resin composition under heating, and the kneading operation can be easily performed.

[0074] The weight average molecular weight (Mw) of the copolymer (B) determined by gel permeation chromatography (GPC) is preferably 1,500 to 30,000, more preferably 6,000 to 25,000, still more preferably 11,000 to 20,000, and particularly preferably 13,000 to 20,000. By using the copolymer (B) with Mw within the above range, it is possible to easily obtain the olefin resin composition, molded article, and crosslinked article that are excellent in handleability when adding and kneading the raw materials of the olefin resin composition and have little stickiness.

[0075] Note that the Mw can be measured, for example, by the following high-speed GPC measuring device and measuring conditions. · High-speed GPC measuring device: HLC8320GPC (manufactured by Tosoh Corporation) · Mobile phase: THF (manufactured by Fujifilm Wako Pure Chemical Corporation, stabilizer-free, liquid chromatography grade) · Column: Two TSKgel Super Multipore HZ-M (manufactured by Tosoh Corporation) connected in series · Sample concentration: 5 mg / mL · Mobile phase flow rate: 0.35 mL / min · Measurement temperature: 40 °C · Standard sample for calibration curve: PStQuick MP-M (manufactured by Tosoh Corporation)

[0076] The flash point of the copolymer (B) is preferably 240 °C or higher, more preferably 280 °C or higher, and even more preferably 300 °C or higher. By using the copolymer (B) with a flash point of at least the above lower limit value, when the raw materials of the olefin resin composition are heated and kneaded, the resulting olefin resin composition is less likely to change color to yellow to brown (less likely to undergo thermal degradation), which is preferable. The flash point can be measured by the Cleveland open cup automatic flash point test (COC).

[0077] For example, when using aluminum nitride as the nitride (C), since the aluminum nitride may react with water to generate ammonia, from the perspective of suppressing the generation of this ammonia, the copolymer (B) is preferably an unmodified ethylene-propylene copolymer that has not been oxidized or modified with an unsaturated carboxylic acid or the like. In particular, the acid value of the copolymer (B) measured in accordance with JIS K 2501:2003 is preferably 0.01 mgKOH / g or less. The melting point of the copolymer (B) measured by a differential scanning calorimeter (DSC) under the above conditions is preferably 15°C or lower, more preferably 10°C or lower, and still more preferably 5°C or lower.

[0078] As the copolymer (B), an ethylene-propylene copolymer produced by a conventionally known method may be used, or a commercially available product may be used.

[0079] The content of the copolymer (B) in the olefin resin composition layer is 21 to 79 parts by mass, preferably 23 to 70 parts by mass, and still more preferably 25 to 65 parts by mass with respect to a total of 100 parts by mass of the ethylene-α-olefin copolymer (A1), the acid-modified ethylene-α-olefin copolymer (A2), and the ethylene-propylene copolymer (B). When the content of the copolymer (B) is at least the lower limit value, when kneading the copolymer (A1), the copolymer (A2), the copolymer (B), and the nitride (C) to produce the olefin resin composition, the surface of the kneading device is less likely to be damaged. When the content of the copolymer (B) is at most the upper limit value, a thin molded body containing the olefin resin composition can be easily obtained from the laminate. When the content of the ethylene-propylene copolymer (B) is within the above range, an olefin resin composition, a molded body, and a crosslinked body that are not sticky, have excellent handleability, and have excellent flexibility (are difficult to become hard and brittle) can be easily obtained.

[0080] <Nitride (C)> The nitride (C) is not particularly limited, and examples thereof include boron nitride, aluminum nitride, silicon nitride, gallium nitride, and titanium nitride. Among these, boron nitride and aluminum nitride are preferable, and aluminum nitride (C1) is more preferable, from the viewpoints such as being able to easily obtain the olefin resin composition, molded article, and crosslinked product having high thermal conductivity. The nitride (C) used in the olefin resin composition may be one kind or two or more kinds.

[0081] The thermal conductivity of the nitride (C) is preferably 100 W / m·K or more, more preferably 110 W / m·K or more, still more preferably 130 W / m·K or more, yet more preferably 150 W / m·K or more, and particularly preferably 200 W / m·K or more. The upper limit of the thermal conductivity is not particularly limited, and the larger the better, but preferably 400 W / m·K or less, more preferably 360 W / m·K or less, and still more preferably 320 W / m·K or less. By using the nitride (C) having a thermal conductivity within the above range, the olefin resin composition, molded article, and crosslinked product having high thermal conductivity, particularly the crosslinked product having a thermal conductivity within the above range, can be easily obtained. The thermal conductivity can be measured by the temperature gradient method (ASTM D5470-1).

[0082] Examples of the shape of the nitride (C) include spherical, cubic, plate-like, columnar, and hexagonal plate-like shapes, and among these, spherical is preferable.

[0083] The average particle diameter of the nitride (C) is preferably 0.5 to 60 μm, more preferably 0.7 to 50 μm, and still more preferably 0.8 to 40 μm. When using the nitride (C) having an average particle diameter within the above range, the wear of the kneader during kneading the raw materials of the olefin resin composition can be suppressed, the olefin resin composition can be obtained with good productivity, and the olefin resin composition, molded article, and crosslinked product having excellent flexibility (difficult to become hard and brittle) can be easily obtained. If the average particle size is too small, nitride (C) will fly around during kneading, resulting in a decrease in the productivity of the olefin resin composition, and the resulting olefin resin composition, molded article, and crosslinked body may easily become hard and brittle. On the other hand, if the average particle size is too large, the kneader may wear out when kneading the raw materials of the olefin resin composition. The average particle size in this specification is a value measured by the laser diffraction / scattering method and converted on a volume basis.

[0084] In applications where higher thermal conductivity is required, for example, the particle size distribution of nitride (C) contained in the olefin resin composition, measured by a laser diffraction type particle size distribution measuring device, preferably has a bimodal distribution. Specifically, the particle size distribution preferably has peaks in the range where the particle size is 0.5 μm or more and less than 5 μm, and in the range where the particle size is 5 μm or more and 60 μm or less. Nitride (C) having such a particle size distribution can be prepared, for example, by mixing nitride (C) (hereinafter also referred to as "nitride (Ca)") in the range where the average particle size is 0.5 μm or more and less than 5 μm and nitride (C) (hereinafter also referred to as "nitride (Cb)") in the range where the average particle size is 5 μm or more and 60 μm or less. By using nitride (Ca) and nitride (Cb) in combination, nitride (Ca) fills the gaps between nitride (Cb), increasing the packing density of nitride (C), so that the thermal conductivity of the resulting olefin resin composition can be further improved.

[0085] From the viewpoints such as being able to easily obtain the olefin resin composition, molded body, and crosslinked body that are excellent in flexibility (difficult to become hard and brittle), in the particle size distribution, the difference between the particle size (hereinafter, also referred to as "particle size a") at the peak position where the particle size is in the range of 0.5 μm or more and less than 5 μm and the particle size (hereinafter, also referred to as "particle size b") at the peak position where the particle size is in the range of 5 μm or more and 60 μm or less is preferably large, preferably 17 to 49 μm, more preferably 23 to 39 μm. For the same reason, the difference in the average particle size between nitride (Ca) and nitride (Cb) is preferably large, and the difference in the average particle size is preferably 17 to 49 μm, more preferably 23 to 39 μm.

[0086] The particle size a is preferably 0.7 to 3.0 μm, more preferably 0.9 to 2.0 μm. The particle size b is preferably 20 to 50 μm, more preferably 25 to 40 μm. The average particle size of nitride (Ca) is preferably 0.7 to 3.0 μm, more preferably 0.9 to 2.0 μm. The average particle size of nitride (Cb) is preferably 20 to 50 μm, more preferably 25 to 40 μm.

[0087] When nitride (C) has a bimodal particle size distribution, the proportion of nitride (C) having a particle size of less than 5 μm in the whole nitride (C) is preferably 10 to 40% by mass, more preferably 20 to 40% by mass, still more preferably 30 to 40% by mass, and the proportion of nitride (C) having a particle size of 5 μm or more is preferably 60 to 90% by mass, more preferably 60 to 80% by mass, still more preferably 60 to 70% by mass. When nitride (Ca) and nitride (Cb) are used in combination, the amount of nitride (Ca) is preferably 10 to 40% by mass, more preferably 20 to 40% by mass, still more preferably 30 to 40% by mass with respect to 100% by mass in total of nitride (Ca) and nitride (Cb). When using nitride (Ca) and nitride (Cb) in combination, the amount of nitride (Cb) is preferably 60 to 90% by mass, more preferably 60 to 80% by mass, and still more preferably 60 to 70% by mass with respect to the total 100% by mass of nitride (Ca) and nitride (Cb). When the ratio or the amount ratio of nitride (Ca) to nitride (Cb) is within the above range, the olefin resin composition, molded article, and crosslinked body having excellent flexibility (difficult to become hard and brittle) can be easily obtained.

[0088] From the viewpoint of heat conduction uniformity and the like, it is preferable that the aspect ratio of nitride (C) is small. Specifically, the aspect ratio of nitride (C) is preferably less than 1.2, more preferably less than 1.1. The aspect ratio is a value obtained by observing the SEM image of nitride (C), measuring the longitudinal length (long side, major axis) and the transverse length (short side, minor axis) of each of 100 randomly selected nitride (C) particles, calculating the longitudinal length / transverse length, and taking the average value.

[0089] Nitride (C) is preferably one that has been subjected to a water resistance treatment. As nitride (C), commercially available products can be used. Also, as nitride (C), those obtained by pulverizing commercially available products may be used.

[0090] The content of nitride (C) in the olefin resin composition layer is 1200 to 1500 parts by mass, preferably 1250 to 1500 parts by mass, more preferably 1300 to 1500 parts by mass with respect to the total 100 parts by mass of the ethylene·α-olefin copolymer (A1), the acid-modified ethylene·α-olefin copolymer (A2), and the ethylene·propylene copolymer (B). When the content of nitride (C) is at least the lower limit value, the olefin resin composition, molded article, and crosslinked body having a high thermal conductivity can be easily obtained. Also, when the content of nitride (C) is at most the upper limit value, the olefin resin composition, molded article, and crosslinked body having excellent flexibility (difficult to become hard and brittle) can be easily obtained.

[0091] <Other components> Within the scope not impairing the object of the present invention, the polar resin layer may contain other components other than the polar resin, the release layer may contain other components other than the release agent, and the olefin resin composition layer may contain components other than the ethylene·α-olefin copolymer (A1), the acid-modified ethylene·α-olefin copolymer (A2), the ethylene·propylene copolymer (B), and the nitride (C). Examples of the other components include oils or polymer components other than the copolymer (A1), the copolymer (A2), and the copolymer (B), flame retardants, weather stabilizers, heat stabilizers, antioxidants, ultraviolet absorbers, antistatic agents, slip agents, antiblocking agents, antifogging agents, nucleating agents, lubricants, pigments, dyes, anti-aging agents, hydrochloric acid absorbers, organic or inorganic foaming agents, crosslinking agents, co-crosslinking agents, crosslinking aids, adhesives, antibacterial agents, surfactants, crystallization aids, impact modifiers, and processing aids. These other components may each be used alone or in combination of two or more.

[0092] Note that the olefin resin composition preferably does not substantially contain components that can flow out of the olefin resin composition at high temperatures (e.g., 150°C) and components that cause contact failures in electronic components. Specifically, the total content of these components is preferably 1% by mass or less based on 100% by mass of the olefin resin composition. Examples of such components include silicone oils and modified silicone oils (liquid silicones) composed of polydimethylsiloxane, polydimethyldiphenylsiloxane, polydimethylhydromethylsiloxane, etc.

[0093] [Flame retardant] The olefin resin composition layer may contain a flame retardant. The flame retardant is not particularly limited, and various known flame retardants can be used. As the flame retardant, inorganic flame retardants are preferred, metal hydroxides are more preferred, and magnesium hydroxide and aluminum hydroxide are even more preferred in terms of being able to exhibit flame retardancy at low temperatures. The flame retardant used in the olefin resin composition may be one kind or two or more kinds.

[0094] Examples of the shape of the flame retardant include spherical, cubic, plate-like, columnar, and hexagonal plate-like shapes, among which spherical is preferred.

[0095] The average particle size of the flame retardant is preferably 8 to 60 μm, more preferably 9 to 50 μm, and even more preferably 10 to 40 μm. When using a flame retardant with an average particle size within the above range, wear of the kneader during kneading of the raw materials of the olefin resin composition can be suppressed, the olefin resin composition can be obtained with good productivity, and the olefin resin composition, molded article, and crosslinked body having excellent flexibility (difficult to become hard and brittle) can be easily obtained. If the average particle size is too small, the flame retardant will fly during kneading, the productivity of the olefin resin composition will decrease, and the resulting olefin resin composition, molded article, and crosslinked body may easily become hard and brittle. On the other hand, if the average particle size is too large, the kneader may wear during kneading of the raw materials of the olefin resin composition.

[0096] The surface of the flame retardant may be surface-treated by a conventionally known method. As the flame retardant, commercially available products can be used. Also, as the flame retardant, those obtained by pulverizing commercially available products may be used.

[0097] When using a flame retardant, the content of the flame retardant in the olefin resin composition is preferably 125 to 400 parts by mass, more preferably 150 to 350 parts by mass, and still more preferably 190 to 300 parts by mass with respect to a total of 100 parts by mass of the ethylene·α-olefin copolymer (A1), the acid-modified ethylene·α-olefin copolymer (A2), and the ethylene·propylene copolymer (B). When the content of the flame retardant is within the above range, it is possible to easily obtain the olefin resin composition, molded article, and crosslinked article having a flame retardancy of HB or higher in the UL94 standard and excellent flexibility (difficult to become hard and brittle).

[0098] <Method for producing olefin resin composition> The method for producing the olefin resin composition is not particularly limited, and the olefin resin composition can be produced by mixing and kneading the copolymer (A1), the copolymer (A2), the copolymer (B), the nitride (C), and the other components used optionally in a predetermined ratio by a known method. Specifically, for example, the olefin resin composition can be produced by mixing and kneading the copolymer (A1), the copolymer (A2), the copolymer (B), the nitride (C), and other components by mixing and kneading means such as an extruder, a Banbury mixer, a mixing roll, a Henschel mixer, and a kneader. The mixing and kneading are preferably carried out under heating according to the raw materials used.

[0099] The nitride (C) may be mixed together with the components other than the nitride (C) constituting the olefin resin composition, or may be added to and mixed with a composition containing all the components other than the nitride (C) constituting the olefin resin composition at the final stage of producing the olefin resin composition. Also, a part of the nitride (C) may be mixed together with the components other than the nitride (C) constituting the olefin resin composition, and the remaining nitride (C) may be added and mixed at the final stage of producing the olefin resin composition. The same applies to the copolymer (A1), copolymer (A2), copolymer (B), and the other components that may be used as necessary.

[0100] ≪Laminate≫ The laminate according to the present invention is a laminate in which the polar resin layer, the release layer, and the olefin resin composition layer are laminated in this order. The laminate may include only the polar resin layer, the release layer, and the olefin resin composition layer, or may include layers other than the polar resin layer, the release layer, and the olefin resin composition layer.

[0101] The laminate may include only one layer each of the polar resin layer, the release layer, and the olefin resin composition layer, or may include a plurality of layers. From the viewpoint of ease of manufacturing a molded body containing the olefin resin composition from the laminate, the laminate preferably includes a polar resin layer / release layer / olefin resin composition layer / release layer / polar resin layer in this order.

[0102] Examples of the method for manufacturing the laminate include a method in which a release sheet coated with a release agent on a base sheet made of a polar resin having an emboss pattern is used to sandwich the olefin resin composition with the release sheet so as to be in the order of base sheet / release agent / the olefin resin composition / release agent / base sheet, and pressing is performed using a hot press device and a cooling press device, and a method of extrusion laminating the release sheet and the olefin resin composition so as to be in the order of base sheet / release agent / the olefin resin composition / release agent / base sheet. When manufacturing a laminate by the method of sandwiching the olefin resin composition with the release sheet and performing pressing using a hot press device and a cooling press device, the adhesion between the sheet containing the olefin resin composition and the release sheet is improved, so that the release sheet is less likely to peel off when manufacturing and carrying the laminate.

[0103] ≪Crosslinked body≫ By crosslinking the olefin resin composition layer in the laminate and then peeling the crosslinked olefin resin composition layer from the polar resin layer and the release layer, a crosslinked body can be obtained. By crosslinking the olefin resin composition layer, bleeding out of components in the olefin resin composition is less likely to occur, and a crosslinked body excellent in heat resistance and thermal conductivity can be easily obtained.

[0104] The crosslinking may be carried out by chemical crosslinking using a crosslinking agent and heating or the like, or may be carried out by radiation crosslinking by irradiating radiation such as electron beams, X-rays, γ-rays, α-rays, and β-rays. Further, both chemical crosslinking and radiation crosslinking may be carried out.

[0105] When carrying out the chemical crosslinking, it is preferable to use a crosslinking agent (use the olefin resin composition containing a crosslinking agent). As the crosslinking agent, a conventionally known crosslinking agent can be used without particular limitation. As the crosslinking agent, an organic peroxide is preferable. When an organic peroxide is used as the crosslinking agent, it is preferable that the olefin resin composition layer contains a conventionally known crosslinking aid. Examples of the crosslinking agent and the crosslinking aid include the crosslinking agent and the crosslinking aid described in International Publication No. 2019 / 180802 and the like.

[0106] The chemical crosslinking is preferably carried out under heating. In this case, the heating conditions are not particularly limited, but preferably include heating at 160 to 200 °C for about 30 minutes to 2 hours.

[0107] As the radiation crosslinking, electron beam crosslinking is preferable. When carrying out the radiation crosslinking, a crosslinking agent may or may not be used. When irradiating an electron beam, it is desirable to carry out irradiation so that the absorbed dose is preferably 0.5 to 100 kGy, more preferably 0.5 to 70 kGy. Further, when crosslinking by electron beam irradiation, the step of irradiating the electron beam so that the absorbed dose per time is within the above range may be carried out a plurality of times.

[0108] When crosslinking the olefin resin composition layer, it is preferable to mold the laminate into a desired shape and then crosslink it. The molding and crosslinking of the laminate may be performed separately or continuously.

[0109] ≪Molded article≫ A molded article containing the olefin resin composition can be obtained from the laminate. Also, a molded article containing the crosslinked body can be obtained from the laminate.

[0110] The molded article is preferably a sheet. The sheet containing the olefin resin composition can be obtained, for example, by forming the laminate into a sheet shape and then peeling the olefin resin composition layer from the polar resin layer and the release layer. The sheet containing the crosslinked olefin resin composition (crosslinked sheet) can be obtained, for example, by crosslinking the olefin resin composition layer after forming the laminate into a sheet shape, and then peeling the crosslinked olefin resin composition layer from the polar resin layer and the release layer. Manufacturing a sheet or a crosslinked sheet in such a manner enables the sheet or the crosslinked sheet to be easily made thinner compared to other manufacturing methods.

[0111] The thickness of the sheet may be appropriately selected according to the desired application, but is usually 1.0 mm or less, preferably 500 μm or less, more preferably 300 μm or less, and even more preferably 200 μm or less. The thickness of the sheet is usually 50 μm or more.

[0112] The sheet is preferably used for heat dissipation of electronic devices and components accompanied by heat generation (e.g., communication devices, high-function printers, liquid crystal displays, LED lighting, servers, car navigation systems, power sources for hybrid vehicles and electric vehicles, personal computers, digital cameras, TV game consoles, HDDs, etc.). Specifically, it is preferably used as a TIM such as a heat dissipation sheet. In particular, since the sheet has excellent thermal conductivity, it is preferably used as a TIM for improving the thermal conductivity between the heat generating body and the heat dissipating member, and between the heat dissipating members. Since the sheet also has excellent heat resistance, it is preferably used for heat generating bodies and heat dissipating members that can reach high temperatures. Furthermore, since the sheet has excellent insulation properties, it is also preferably used for applications that require insulation, for example, as an alternative material for insulating paper, or as an insulating coating material (coating layer) for electric wires or cables used for motor wires, etc. In addition, by using the sheet for a part of the housing of various electronic devices such as notebook computers and mobile devices, for other parts, for example, parts that are often touched by hands during operation, a material with a reduced metal oxide content or a material that does not contain metal oxide can be used to manufacture a housing that can reduce the possibility of symptoms such as low-temperature burns during long-term operation. Such a housing can be manufactured, for example, by installing a plurality of resin injection gates in a mold for molding the housing and injecting resins with different compositions for each gate.

[0113] In addition to the above applications, the molded body is also used for, for example, architectural applications such as building materials, and clothing applications.

Examples

[0114] Hereinafter, the present invention will be described more specifically based on examples, but the present invention is not limited to these examples.

[0115] As the ethylene-α-olefin copolymer (A1), the following copolymer (A1-1) was used. · "Copolymer (A1-1)": Ethylene-1-butene copolymer (density = 885 kg / m 3 , MFR (190 °C, 2.16 kg load) = 18 g / 10 min, melting point = 66 °C, Shore A hardness = 86)

[0116] As the acid-modified ethylene·α-olefin copolymer (A2), the following copolymer (A2-1) was used. · "Copolymer (A2-1)": Acid-modified ethylene·1-butene copolymer (density 872 kg / m 3 , MFR (190 °C, 2.16 kg load) = 40 g / 10 min, melting point = 55 °C)

[0117] As the ethylene·propylene copolymer (B), the following copolymer (B-1) was used. · "Copolymer (B-1)": Ethylene·propylene copolymer (BF viscosity at 25 °C: 190,000 mPa·s, weight-average molecular weight (Mw) = 16,000, flash point = 300 °C or higher, acid value = less than 0.01 mg-KOH / g, melting point = -2 °C)

[0118] <Nitride (C)> As the nitride (C), the following commercially available products were used. · "Nitride (C-1)": "HFS-30a" aluminum nitride (manufactured by Tokuyama Corporation, average particle size: 30 μm) · "Nitride (C-2)": "HF-01Da" aluminum nitride (manufactured by Tokuyama Corporation, average particle size: 1 μm)

[0119] <Polar resin layer and release layer> As the polar resin layer and release layer, the following commercially available protective sheets were used. · "Protective sheet (1)": "A3E" (manufactured by Nippa Co., Ltd., PET sheet, with release layer (with release agent), thickness = 38 μm, peel load = 40 mN, embossed pattern included (diamond-shaped)) · "Protective sheet (2)": "PG-28N" (manufactured by Ishijima Chemical Industry Co., Ltd., PET sheet, without release layer (without release agent), thickness 50 μm, embossed pattern included (silk-like)) · "Protective sheet (3)": "PG-1" (manufactured by Ishijima Chemical Industry Co., Ltd., PET sheet, without release layer (without release agent), thickness 50 μm, embossed pattern included (cloth-like)) · "Protective Sheet (4)": "NL-ASI5" (manufactured by Nipper Co., Ltd., PET sheet, with release layer (with release agent), thickness 50 μm, peel load = 20 mN, non-containing embossed pattern) · "Protective Sheet (5)": Embossed sheet (manufactured by Oishi Sangyo Co., Ltd., LDPE sheet, without release layer (without release agent), thickness 70 μm, containing embossed pattern (gauze-like)) · "Protective Sheet (6)": Embossed sheet (manufactured by Oishi Sangyo Co., Ltd., LDPE sheet, without release layer (without release agent), thickness 230 μm, containing embossed pattern (diamond-like))

[0120] [Example 1] <Preparation of Resin Composition> The copolymer (A1-1), copolymer (A2-1), copolymer (B-1), nitride (C-1), and nitride (C-2) were placed in a lab plastomill (manufactured by Toyo Seiki Seisakusho Co., Ltd., model "30C150") so as to have the numerical values (parts by mass) shown in Table 1 below, and kneaded at a kneading temperature of 160°C and a torque rotation speed of 30 rpm for 10 minutes to prepare an olefin-based resin composition.

[0121] <Production of Laminate (Hot Press Sheet)> Using a protective sheet (1) with a size of 200 mm × 200 mm, the prepared olefin-based resin composition was sandwiched vertically in the order of PET sheet / release agent / olefin-based resin composition / release agent / PET sheet, and a laminate (hot press sheet) with a size of 150 mm × 150 mm was produced using a hot press device and a cooling press device. The press conditions using the hot press device and the press conditions using the cooling press device were both hydraulic pressure: 100 kgf / cm 2 , press time: 5 minutes, and the temperature conditions when pressing using the hot press device were as described in Table 1. A part of the hot press sheet obtained by this method was cut out, and the thickness of the sheet formed from the olefin-based resin composition obtained by peeling the protective sheet (1) in the cut-out hot press sheet was as described in Table 1. In order to measure the physical property values described below, a laminate (sheet for measuring physical property values) prepared in the same manner as the above-described method was also prepared, except that the pressing conditions were changed so that the thickness of the sheet formed from the olefin resin composition was 1 mm.

[0122] <Production of Crosslinked Sheet> Using a batch conveyor (EPS-750, manufactured by NHV Corporation), the prepared hot press sheet and the sheet for measuring physical property values were irradiated with an electron beam of 20 kGy twice for the hot press sheet and 8 times for the sheet for measuring physical property values, thereby crosslinking the olefin resin composition layer. A crosslinked sheet was produced by peeling off the sheet formed from the crosslinked body, which is the crosslinked olefin resin composition, from the protective sheet (1).

[0123] [Examples 2 to 5 and Comparative Examples 1 to 5] Laminates (hot press sheets and sheets for measuring physical property values) and crosslinked sheets were produced in the same manner as in Example 1, except that the contents of the copolymer (A1-1), copolymer (A2-1), copolymer (B-1), nitride (C-1) and nitride (C-2), and the type of the protective sheet were changed as described in Table 1 below.

[0124] [Evaluation] <Scratching of the Apparatus Surface> After kneading the olefin resin composition with a lab plastomill, when the surface of the lab plastomill was wiped with a waste cloth, it was visually evaluated according to the following criteria whether metal powder was generated due to scratching of the lab plastomill. A: No metal powder was attached to the waste cloth. B: A very small amount of metal powder was attached to the waste cloth. C: A significant amount of metal powder was attached to the waste cloth.

[0125] <Possibility of Sheet Formation> When producing a hot-pressed sheet using a hot press device and a cooling press device, if the olefin resin composition was spread out to form a sheet, it was evaluated as A; if the olefin resin composition was compatible with the protective sheet and did not form a sheet, it was evaluated as B.

[0126] <Tear at the time of peeling the protective sheet> When removing the protective sheet from the sheet formed from the crosslinked body to recover the crosslinked sheet, the ratio of the crosslinked body adhering to the protective sheet was evaluated according to the following criteria. A: No crosslinked body adhered to the protective sheet. B: The crosslinked body adhered at a ratio of less than 5% with respect to the area of the protective sheet. C: The crosslinked body adhered at a ratio of 5% or more with respect to the area of the protective sheet. When the evaluation is A or B, it is said that "the crosslinked sheet did not tear"; when the evaluation is C, it is said that "the crosslinked sheet tore".

[0127] <Heat resistance> Regarding the crosslinked sheet produced from the sheet for measuring physical property values, as a solid viscoelasticity measuring device, RSA-III (manufactured by TA Instruments) was used. The deformation mode was tension, the frequency was 1 Hz, the temperature range was -50 to 240 °C, the heating rate was 3 °C / min, and the temperature at which the rubber plateau region continued was measured under a nitrogen atmosphere. The temperature at which the rubber plateau region continued was evaluated as A when it reached the upper limit of the temperature range of 240 °C, and as B when it did not reach 240 °C.

[0128] <Thermal conductivity> Regarding the hot-pressed sheet and the crosslinked sheet produced from the sheet for measuring physical property values, the thermal conductivity was evaluated by the temperature gradient method (ASTM D5470-1) and the periodic heating method (ISO22007-3). Specifically, for the temperature gradient method, measurement was performed on the crosslinked sheet produced from the sheet for measuring physical property values. As the measuring device, TCM1001 (manufactured by Resca Co., Ltd.) was used, and the measurement was performed with the pressure during measurement set to 0.3 MPa. Regarding the periodic heating method, measurements were taken on the crosslinked sheet produced from the heat press sheet. As the measuring device, a thermal diffusion measuring device 1r (manufactured by I-Face Co., Ltd.) was used. The results are shown in Table 1. Regarding the thermal conductivity, when the thermal conductivity is 3.5 W / m·K or more by the temperature gradient method and 7.0 W / m·K or more by the periodic heating method, it can be said that the crosslinked body has sufficient thermal conductivity.

[0129] <Volume resistivity> Regarding the crosslinked sheet produced from the heat press sheet, the volume resistivity was measured by a method conforming to ASTM D257:2007. The measuring device and measuring conditions were: test model: 8340A (manufactured by C&D Co., Ltd.), electrode diameter (main electrode): 25 mm Φ, guard electrode: inner diameter 38 mm Φ · outer diameter 50 mm Φ, measuring environment: 23 ± 2°C · 50 ± 5% RH, applied voltage: 500 V, applied time: 60 seconds, discharging time: 5 seconds, number of tests: 3 times. The average value of the three measurements is shown in Table 1. When the volume resistivity is 1.0×10 14 Ω·cm or more, it can be said that the crosslinked body has sufficient volume resistivity.

[0130] <Dielectric breakdown strength> Regarding the crosslinked sheet produced from the heat press sheet, the dielectric breakdown strength was measured by a method conforming to ASTM D149. The measuring conditions were: ambient medium: silicone oil, power supply: AC 50 Hz, electrode: upper part is Φ25 mm cylindrical, lower part is a copper plate 100×100 mm, measuring temperature: 23 ± 2°C, voltage rising speed: 1 kV / second, number of tests: 3 times. The average value of the three measurements is shown in Table 1. When the dielectric breakdown strength is 30 kV / mm or more, it can be said that the crosslinked body has sufficient dielectric breakdown strength.

[0131]

Table 1

[0132] When the protective sheet is "emboss pattern-free" or "without release agent", when peeling the protective sheet to recover the crosslinked sheet, the crosslinked sheet was torn (Comparative Examples 1 to 3). On the other hand, when the protective sheet is "embossed pattern-containing" and "with release agent", the crosslinked sheet was not torn (Examples 1 to 5).

[0133] When the protective sheet is an "LDPE sheet", it was found that even if the temperature during hot pressing is below the resin melting point, the protective sheet and the resin composition are compatible and the sheet cannot be produced (Comparative Examples 4 to 5). From the above, it was found that the protective sheet needs to satisfy the conditions of "with emboss", "with release agent", and "not an LDPE sheet".

Claims

【Claim 1】 A polar resin layer, a release layer, and an olefin resin composition layer are laminated in this order, at least one surface of the polar resin layer has an embossed pattern, the release layer is adjacent to the surface of the polar resin layer having the embossed pattern, the olefin resin composition layer contains an ethylene / α-olefin copolymer (A1), an acid-modified ethylene / α-olefin copolymer (A2), an ethylene / propylene copolymer (B), and a nitride (C), the ethylene / α-olefin copolymer (A1) satisfies the following requirements (A1-1) to (A1-4), the acid-modified ethylene / α-olefin copolymer (A2) satisfies the following requirements (A2-1) to (A2-2), with respect to a total of 100 parts by mass of the ethylene / α-olefin copolymer (A1), the acid-modified ethylene / α-olefin copolymer (A2), and the ethylene / propylene copolymer (B), the total content of the ethylene / α-olefin copolymer (A1) and the acid-modified ethylene / α-olefin copolymer (A2) is 21 to 79 parts by mass, the content of the ethylene / propylene copolymer (B) is 21 to 79 parts by mass, and the content of the nitride (C) is 1200 to 1500 parts by mass, the mass ratio of the content of the ethylene / α-olefin copolymer (A1) to the content of the acid-modified ethylene / α-olefin copolymer (A2) [content of copolymer (A1) / content of copolymer (A2)] is 99 / 1 to 1 / 99; a laminate; Requirement (A1-1): The ethylene / α-olefin copolymer (A1) contains a structural unit (i) derived from ethylene and a structural unit (ii) derived from an α-olefin having 4 to 20 carbon atoms; Requirement (A1-2): The melt flow rate (MFR) measured under the conditions of 190 °C and a load of 2.16 kg in accordance with ASTM D1238 is 5 to 100 g / 10 min; Requirement (A1-3): The Shore A hardness 15 seconds after the start of indenter contact in a sample of 7 laminated cross-linked sheets each 1 mm thick measured in accordance with ASTM D2240 is 75 to 99; Requirement (A1-4): The ethylene / α-olefin copolymer (A1) is unmodified; Requirement (A2-1): The acid-modified ethylene / α-olefin copolymer (A2) is obtained by modifying an ethylene / α-olefin copolymer containing a structural unit (i) derived from ethylene and a structural unit (ii) derived from an α-olefin having 4 to 20 carbon atoms with an unsaturated carboxylic acid or its derivative; Requirement (A2-2): The MFR measured under the conditions of 190 ° C and a load of 2.16 kg in accordance with ASTM D1238 is 5 to 100 g / 10 min. **Claim 2** The laminate according to claim 1, wherein the polar resin layer contains a polyester resin. **Claim 3** The laminate according to claim 1 or 2, wherein the embossed pattern is diamond-shaped.

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