Olefin-based resin composition, cross-linked body, laminate, molded body and sheet

Abstract

To provide an olefin-based resin composition containing a nitride capable of reducing the thickness of a molded body without damaging the surface of a kneader in producing a composition.SOLUTION: There is provided an olefin-based resin composition which comprises an ethylene-α-olefin copolymer (A1), an acid-modified ethylene-α-olefin copolymer (A2), an ethylene-propylene copolymer (B) and a nitride (C), wherein the copolymer (A1) and the copolymer (A2) satisfy specific requirements, the total content of the copolymer (A1) and the copolymer (A2) is 21 to 79 pts.mass based on 100 pts.mass of the total of the copolymer (A1), the copolymer (A2) and the copolymer (B), the content of the copolymer (B) is 21 to 79 pts.mass, the content of the nitride (C) is 1200 to 1500 pts.mass and the mass ratio of the content of the copolymer (A1) to the content of the copolymer (A2) is 99 / 1 to 1 / 99.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an olefin resin composition, a crosslinked body, a laminate, a molded body, and a sheet.

Background Art

[0002] In recent years, the high functionality and miniaturization of electronic devices have been progressing, and the density of electronic components has been increasing. For this reason, for the purpose of ensuring the normal operation and lifespan of electronic devices and electronic components, the control of heat generated from these has become a major issue. As one of the countermeasures against this issue, a method of 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 the housing itself as a heat dissipation member 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 TIM in a predetermined shape. The binder varies greatly depending on the type of TIM, but 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 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 precipitate 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-based resins, styrene-based thermoplastic elastomers, and waxes, and discloses that the resin composition can be used as a TIM.

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

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 release sheet, the sheet sometimes tore. Further, when using a nitride such as a metal nitride as a filler, when kneading a binder and a filler to produce a thermally conductive composition or a resin composition, the surface of the kneader was sometimes damaged.

[0010] The present invention has been made in view of the above circumstances, and an object thereof is to provide an olefin-based resin composition containing a nitride that does not damage the surface of a kneader during production of the composition and enables further thinning of a molded body.

Means for Solving the Problems

[0011] The present inventors intensively studied to solve the above problems. As a result, according to the following configuration examples, it was 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] It 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 from 99 / 1 to 1 / 99. Olefin resin composition; 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 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 a derivative thereof. 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 olefin resin composition according to [1], wherein the α-olefin that leads to the structural unit (ii) in the ethylene-α-olefin copolymer (A1) and / or the acid-modified ethylene-α-olefin copolymer (A2) is 1-butene.

[0014] [3] The olefin resin composition according to [1] or [2], containing an ethylene-propylene copolymer (B) that satisfies the following requirement (B-1). Requirement (B-1): The Brookfield viscosity measured at 25°C is 100,000 to 300,000 mPa·s.

[0015] [4] The olefin resin composition according to any one of [1] to [3], wherein the nitride (C) is aluminum nitride (C1).

[0016] [5] A crosslinked body obtained by crosslinking the olefin resin composition according to any one of [1] to [4].

[0017] [6] A laminate in which a sheet containing the crosslinked body according to [5] and a release sheet are laminated.

[0018] [7] The laminate according to [6], wherein the release sheet is a polyester sheet.

[0019] [8] A molded article containing the olefin resin composition according to any one of [1] to [4].

[0020] [9] A molded article containing the crosslinked body according to [5].

[0021]

[10] A sheet containing the crosslinked body according to [5]. [Advantages of the Invention]

[0022] According to the present invention, it is possible to provide an olefin resin composition containing a nitride that does not damage the surface of a kneader during the production of the composition and that enables further thinning of the molded article. [Modes for Carrying Out the Invention]

[0023] Hereinafter, the present invention will be specifically described. In this specification, "~" 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 encompassing 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 refers to "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, there is no particular distinction made between a sheet and a film, etc., and a film (plate)-shaped molded article is generically referred to as a sheet.

[0024] ≪Olefin-based resin composition≫ The olefin-based resin composition according to the present invention (hereinafter also referred to as "the present composition") contains an ethylene·α-olefin copolymer (A1), an acid-modified ethylene·α-olefin copolymer (A2), an ethylene·propylene copolymer (B), and a nitride (C).

[0025] For example, sandwich the present composition between two release sheets, perform hot pressing and cooling pressing to produce a laminate in which the release sheets and the sheet containing the present composition are laminated, then crosslink the present composition in the state of the laminate, and then peel the sheet containing the crosslinked present composition from the release sheets to obtain a crosslinked body (crosslinked sheet) from the present composition. The crosslinked sheet can be used, for example, as a TIM.

[0026] The thermal conductivity of the crosslinked body (crosslinked sheet) obtained from the present composition 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, 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 product (crosslinked sheet) obtained from this composition, measured by the periodic heating method (ISO 22007-3, thickness: 200 μm or less), is preferably 7.0 W / m·K or more, more preferably 7.3 W / m·K or more, and even 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 the crosslinked product with the thermal conductivity in the above range has excellent thermal conductivity. Specifically, the thermal conductivity is measured by the method described in the column of the following examples.

[0027] The volume resistivity of the crosslinked product (crosslinked sheet) obtained from this composition is preferably 1.0×10 14 Ω·cm or more, more preferably 3.0×10 14 Ω·cm or more, and even 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 the crosslinked product with the volume resistivity in the above range has excellent electrical insulation properties. Specifically, the volume resistivity is measured by the method described in the column of the following examples.

[0028] The dielectric breakdown strength of the crosslinked product (crosslinked sheet) obtained from this composition is preferably 30 kV / mm or more, more preferably 35 kV / mm or more, and even more preferably 40 kV / mm or more. The upper limit of the dielectric breakdown strength is, for example, 60 kV / mm. The crosslinked product with the dielectric breakdown strength in 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.

[0029] In the crosslinked product (crosslinked sheet) obtained from this composition, using RSA-III (manufactured by TA Instruments) as a solid viscoelastic measurement device, 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. The crosslinked product with the upper limit value of the temperature range being 240°C or higher can be said to have excellent heat resistance.

[0030] <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) used in this composition may be one kind or two or more kinds.

[0031] 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.

[0032] 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).

[0033] 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 the resulting molded body and crosslinked product being excellently balanced in terms of 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.

[0034] 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 biomass-derived monomers and fossil fuel-derived monomers may be used. The α-olefin used as a raw material for the copolymer (A1) may be one kind or two or more kinds.

[0035] 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 even more preferably 13 to 60 g / 10 min. The copolymer (A1) with the MFR within the above range is easy to mix with the nitride (C), and when kneaded with the nitride (C), the fluidity is hardly reduced and it is hardly hardened. When the MFR of the copolymer (A1) is equal to or higher than the lower limit value, the decrease in the fluidity of the present composition can be suppressed, and it is easy to thinly mold the present composition or a crosslinked product obtained by crosslinking the present composition. When the MFR of the copolymer (A1) is equal to or lower than the upper limit value, the present composition has appropriate fluidity and the present composition can be easily molded.

[0036] Requirement (A1-3) The Shore A hardness 15 seconds after the start of the indentation needle contact in a sample in which 7 crosslinked 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.

[0037] 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, it can adhere to a heating element and a heat radiating member, etc. (because it is excellent in following the unevenness on the surface of the heating element and the heat radiating member, etc.), and since the heat from the heating element can be efficiently transmitted to the heat radiating member, the crosslinked product can be particularly preferably used as a TIM. In addition, when the Shore A hardness of the copolymer (A1) is at least the above lower limit value, a thin molded product can be easily obtained from this composition.

[0038] Requirement (A1-4) The ethylene-α-olefin copolymer (A1) is unmodified.

[0039] 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 . 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.

[0040] 〈Measurement conditions for melting point〉 Using a differential scanning calorimeter, about 5.0 mg of the 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 and 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 taken as the melting peak, and the temperature at which the melting peak appears is taken as the melting point. When the melting peak is multimodal, the temperature at which the melting peak on the highest temperature side appears is taken as the melting point.

[0041] The elongation at break measured in accordance with ASTM D638 of the copolymer (A1) is preferably 500% or more, more preferably 600% or more, still more preferably 700% or more, from the viewpoint that the resulting molded article and crosslinked product are less likely to be hard and brittle, and the upper limit is, for example, 1200% or less.

[0042] As the copolymer (A1), a copolymer produced by a conventionally known method or a commercially available product may be used.

[0043] <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)". Since the present composition contains the copolymer (A2), a thin molded article can be easily obtained from the present composition. The copolymer (A2) may be one kind or two or more kinds.

[0044] 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 modification with an unsaturated carboxylic acid or a derivative thereof is also referred to as "copolymer (a2)". The copolymer (a2) is preferably an ethylene·α-olefin copolymer consisting only of the structural unit (i) and the structural unit (ii). The copolymer (a2) preferably does not contain a structural unit derived from propylene.

[0045] The content (ethylene content) of the structural unit (i) in the copolymer (a2) 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).

[0046] 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, it is even more preferable that the copolymer (a2) is an ethylene·1-butene copolymer. As the copolymer (a2), the copolymer (A1) may be used.

[0047] 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.

[0048] Examples of the unsaturated carboxylic acid that modifies 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 acid-N-monoethylamide, maleic acid-N,N-diethylamide, maleic acid-N-monobutylamide, maleic acid-N,N-dibutylamide, fumaric monoamide, fumaric diamide, fumaric acid-N-monobutylamide, and fumaric acid-N,N-dibutylamide; Imides such as maleimide, N-butylmaleimide, and N-phenylmaleimide; Metal salts such as sodium acrylate, sodium methacrylate, potassium acrylate, and potassium methacrylate may be mentioned. Among the unsaturated carboxylic acids and their derivatives, maleic acid and maleic anhydride are preferred, and maleic anhydride is more preferred.

[0049] The unsaturated carboxylic acid or its derivative for modifying the copolymer (a2) may be derived from biomass, may be derived from fossil fuels, or both a biomass-derived monomer and a fossil fuel-derived monomer may be used.

[0050] 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 later 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 the copolymer (A2).

[0051] 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 part by mass, preferably 0.0010 to 0.30 part by mass, based on 100 parts by mass of the copolymer (a2).

[0052] 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. The organic solvent is not particularly limited as long as it can dissolve the radical initiator.

[0053] The graft polymerization can be carried out by a conventionally known method. For example, the copolymer (a2) is dissolved in an organic solvent, and an unsaturated carboxylic acid or its derivative, a radical initiator, etc. are added to the resulting 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.

[0054] Also, in a device such as an extruder, in the absence of a solvent, an unsaturated carboxylic acid or its derivative and the copolymer (a2) may be reacted in the presence of a radical initiator to produce the acid-modified ethylene / α-olefin copolymer (A2). 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.

[0055] The degree of acid modification (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. Degree of acid modification (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 degree of acid modification 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 assigned to the carbonyl group and a separately prepared calibration curve.

[0056] 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, and even 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), is less likely to have a decrease in fluidity when kneaded with the nitride (C), and is less likely to become hard. When the MFR of the copolymer (A2) is equal to or higher than the lower limit value, a thin molded body can be easily obtained from the present composition. When the MFR of the copolymer (A2) is equal to or lower than the upper limit value, the present composition has appropriate fluidity and can be easily molded.

[0057] 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 , even more preferably 863 to 890 kg / m 3 . 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 even more preferably 40 to 70 °C.

[0058] The Shore A hardness 15 seconds after the start of the needle contact in a sample in which 7 crosslinked sheets with a thickness of 1 mm are stacked, measured in accordance with ASTM D2240 in the copolymer (A2), is preferably 20 to 99, more preferably 25 to 95, and even 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 dissipation member, etc. (because it has excellent surface unevenness followability 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 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.

[0059] Based on 100 parts by mass in total 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, 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 this composition by kneading the copolymer (A1), the copolymer (A2), the copolymer (B), and the nitride (C), it becomes difficult to damage the surface of the kneading apparatus. When the total content of the copolymer (A1) and the copolymer (A2) is at or above the above lower limit value, a thin molded article can be easily obtained from this composition.

[0060] 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, 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 or below the above 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 can be easily obtained from this composition. When the mass ratio of the content of the copolymer (A1) to the content of the copolymer (A2) is at or above the above lower limit value, an increase in the hardness of this composition can be suppressed, and when producing this composition by kneading the copolymer (A1), the copolymer (A2), the copolymer (B), and the nitride (C), it becomes difficult to damage the surface of the kneading apparatus.

[0061] <Ethylene-propylene copolymer (B)> This composition contains an ethylene-propylene copolymer (B). By including the ethylene-propylene copolymer (B) in this composition, it is possible to easily obtain a composition, a molded article, and a crosslinked body having a higher thermal conductivity. The ethylene-propylene copolymer (B) is also referred to as "copolymer (B)". The copolymer (B) used in this composition may be one type or two or more types.

[0062] 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%, and still more preferably 40 to 60 mol% with respect to a total of 100 mol% of the structural unit (I) and the structural unit (II).

[0063] Ethylene and propylene may be derived from biomass, may be derived from fossil fuels, or both a biomass-derived monomer and a fossil fuel-derived monomer may be used.

[0064] 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, and still more preferably 160,000 to 240,000 mPa·s. By using the copolymer (B) having a BF viscosity of not less than the lower limit value, a composition, a molded article, and a crosslinked product of the present composition, which are excellent in handleability when adding and kneading the raw materials of the present composition and have little stickiness, can be easily obtained. Further, by using the copolymer (B) having a BF viscosity of not more than the upper limit value, when kneading the raw materials of the present composition under heating, the viscosity is not too high and the kneading operation can be easily performed.

[0065] The weight average molecular weight (Mw) of the copolymer (B) determined by gel permeation chromatography (GPC) is preferably from 1,500 to 30,000, more preferably from 6,000 to 25,000, still more preferably from 11,000 to 20,000, and particularly preferably from 13,000 to 20,000. By using the copolymer (B) having Mw in the above range, a composition, a molded article, and a crosslinked product of the present composition, which are excellent in handleability when adding and kneading the raw materials of the present composition and have little stickiness, can be easily obtained.

[0066] The Mw can be measured, for example, by the following high-speed GPC measuring apparatus and measuring conditions. · High-speed GPC measuring apparatus: HLC8320GPC (manufactured by Tosoh Corporation) · Mobile phase: THF (manufactured by Fujifilm Wako Pure Chemical Corporation, without stabilizer, grade for liquid chromatography) · 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 · Measuring temperature: 40 °C · Standard sample for calibration curve: PStQuick MP-M (manufactured by Tosoh Corporation)

[0067] The flash point of the copolymer (B) is preferably 240 °C or higher, more preferably 280 °C or higher, still more preferably 300 °C or higher. By using the copolymer (B) whose flash point is at least the above lower limit value, when the raw materials of the present composition are heat-kneaded, the resulting present composition is less likely to change color to yellow to brown (less likely to undergo thermal deterioration), which is preferable. The flash point can be measured by the Cleveland open cup flash point test (COC).

[0068] For example, when using aluminum nitride as the nitride (C), since the aluminum nitride may react with water to generate ammonia, from the viewpoint of suppressing the generation of this ammonia, etc., the copolymer (B) is preferably an unmodified ethylene-propylene copolymer that is not 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 even more preferably 5°C or lower.

[0069] 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.

[0070] The content of the copolymer (B) in the present composition is 21 to 79 parts by mass, preferably 23 to 70 parts by mass, and even 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 above lower limit value, when kneading the copolymer (A1), the copolymer (A2), the copolymer (B), and the nitride (C) to produce the present composition, the surface of the kneading device is less likely to be damaged. When the content of the copolymer (B) is at most the above upper limit value, a thin molded article can be easily obtained from the present composition. When the content of the ethylene-propylene copolymer (B) is within the above range, a composition, a molded article, and a crosslinked article that are not sticky, have excellent handleability, and have excellent flexibility (are difficult to become hard and brittle) can be easily obtained.

[0071] <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 of easily obtaining a composition, a molded article, and a crosslinked article having high thermal conductivity. The nitride (C) used in the present composition may be one kind or two or more kinds.

[0072] 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, further 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 it is 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 a nitride (C) having a thermal conductivity within the above range, a composition, a molded article, and a crosslinked article having high thermal conductivity, particularly a crosslinked article 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).

[0073] Examples of the shape of the nitride (C) include spherical, cubic, plate-like, columnar, and hexagonal plate-like shapes, among which spherical is preferable.

[0074] 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) with an average particle diameter within the above range, abrasion of the kneader during kneading of the raw materials of the present composition can be suppressed, the present composition can be obtained with good productivity, and the present composition, molded body, and crosslinked body having excellent flexibility (difficult to become hard and brittle) can be easily obtained. If the average particle diameter is too small, the nitride (C) will fly during kneading, the productivity of the present composition will decrease, and the obtained present composition, molded body, and crosslinked body may easily become hard and brittle. On the other hand, if the average particle diameter is too large, the kneader may be abraded when kneading the raw materials of the present composition. The average particle diameter in this specification is a value measured by the laser diffraction / scattering method and converted on a volume basis.

[0075] In applications where higher thermal conductivity is required, for example, the particle size distribution of the nitride (C) contained in the present 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 diameter is 0.5 μm or more and less than 5 μm, and in the range where the particle diameter is 5 μm or more and 60 μm or less. The nitride (C) having such a particle size distribution can be prepared, for example, by mixing a nitride (C) (hereinafter also referred to as "nitride (Ca)") having an average particle diameter in the range of 0.5 μm or more and less than 5 μm and a nitride (C) (hereinafter also referred to as "nitride (Cb)") having an average particle diameter in the range of 5 μm or more and 60 μm or less. By using the nitride (Ca) and the nitride (Cb) in combination, the nitride (Ca) fills the gaps between the nitride (Cb), and the packing density of the nitride (C) increases, so that the thermal conductivity of the obtained present composition can be further improved.

[0076] From the viewpoints such as being able to easily obtain the present composition, molded body, and crosslinked body that are excellent in flexibility (difficult to become hard and brittle), in the above particle size distribution, the particle size at the peak position where the particle diameter is in the range of 0.5 μm or more and less than 5 μm (hereinafter, also referred to as "particle diameter a") and the particle diameter at the peak position where the particle diameter is in the range of 5 μm or more and 60 μm or less (hereinafter, also referred to as "particle diameter b") preferably have a larger difference, preferably 17 to 49 μm, more preferably 23 to 39 μm. For the same reason, the difference in the average particle diameter between nitride (Ca) and nitride (Cb) preferably has a larger difference, and the difference in the average particle diameter is preferably 17 to 49 μm, more preferably 23 to 39 μm.

[0077] The particle diameter a is preferably 0.7 to 3.0 μm, more preferably 0.9 to 2.0 μm. The particle diameter b is preferably 20 to 50 μm, more preferably 25 to 40 μm. The average particle diameter of nitride (Ca) is preferably 0.7 to 3.0 μm, more preferably 0.9 to 2.0 μm. The average particle diameter of nitride (Cb) is preferably 20 to 50 μm, more preferably 25 to 40 μm.

[0078] When nitride (C) has a bimodal particle size distribution, the proportion of nitride (C) having a particle diameter 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 diameter 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, based on 100% by mass in total of nitride (Ca) and nitride (Cb). When the ratio or the amount ratio of nitride (Ca) and nitride (Cb) is within the above range, a composition, a molded article, and a crosslinked product excellent in flexibility (difficult to become hard and brittle) can be easily obtained.

[0079] From the viewpoint of heat conduction uniformity and the like, nitride (C) preferably has a small aspect ratio. 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.

[0080] Nitride (C) is preferably subjected to a water resistance treatment. As the nitride (C), commercially available products can be used. Further, as the nitride (C), those obtained by pulverizing commercially available products may be used.

[0081] The content of nitride (C) in the present composition is 1200 to 1500 parts by mass, preferably 1250 to 1500 parts by mass, and more preferably 1300 to 1500 parts by mass, based on 100 parts by mass in total 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, a composition, a molded article, and a crosslinked product having a high thermal conductivity can be easily obtained. Further, when the content of nitride (C) is at most the upper limit value, a composition, a molded article, and a crosslinked product excellent in flexibility (difficult to become hard and brittle) can be easily obtained.

[0082] <Other components> The composition may contain other 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) as long as the object of the present invention is not impaired. 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, mold release agents, 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.

[0083] It should be noted that the composition preferably does not substantially contain components that can flow out of the 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 composition. Examples of such components include silicone oils and modified silicone oils (liquid silicones) composed of polydimethylsiloxane, polydimethyldiphenylsiloxane, and polydimethylhydromethylsiloxane.

[0084] [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 composition may be one kind or two or more kinds.

[0085] Examples of the shape of the flame retardant include spherical, cubic, plate-like, columnar, and hexagonal plate-like shapes, among which spherical is preferred.

[0086] The average particle diameter 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 having an average particle diameter within the above range, abrasion of the kneader during kneading of the raw materials of the present composition can be suppressed, the present composition can be obtained with good productivity, and a present composition, molded article, and crosslinked product having excellent flexibility (difficult to become hard and brittle) can be easily obtained. If the average particle diameter is too small, the flame retardant will fly during kneading, the productivity of the present composition will decrease, and the resulting present composition, molded article, and crosslinked product may easily become hard and brittle. On the other hand, if the average particle diameter is too large, there is a risk of abrasion of the kneader when kneading the raw materials of the present composition.

[0087] 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.

[0088] When using a flame retardant, the content of the flame retardant in the present composition is preferably 125 to 400 parts by mass, more preferably 150 to 350 parts by mass, and even 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, a present composition, molded article, and crosslinked product having flame retardancy of HB or higher in the UL94 standard and excellent flexibility (difficult to become hard and brittle) can be easily obtained.

[0089] <Manufacturing method of the present composition> The manufacturing method of the present composition is not particularly limited, and the copolymer (A1), copolymer (A2), copolymer (B), nitride (C), and the other components optionally used can be mixed and kneaded by a known method at a predetermined ratio to manufacture the present composition. Specifically, for example, the copolymer (A1), copolymer (A2), copolymer (B), nitride (C), and other components can be mixed and kneaded by mixing and kneading means such as an extruder, Banbury mixer, mixing roll, Henschel mixer, and kneader to produce the present composition. The mixing and kneading are preferably carried out under heating according to the raw materials used.

[0090] The nitride (C) may be mixed together with the components other than the nitride (C) constituting the present composition, or added to and mixed with a composition containing all the components other than the nitride (C) constituting the present composition at the final stage of producing the present composition. Also, a part of the nitride (C) may be mixed together with the components other than the nitride (C) constituting the present composition, and the remaining nitride (C) may be added and mixed at the final stage of producing the present composition. The same also applies to the copolymer (A1), copolymer (A2), copolymer (B), and the other components that may be used as necessary.

[0091] ≪Crosslinked body≫ The crosslinked body according to the present invention is obtained by crosslinking the present composition. By crosslinking the present composition, it becomes difficult for components in the present composition to bleed out, and a crosslinked body excellent in heat resistance and thermal conductivity can be easily obtained. The crosslinking may be carried out by chemical crosslinking using a crosslinking agent and heating or the like, or by radiation crosslinking by irradiating radiation such as electron beams, X-rays, γ-rays, α-rays, and β-rays. Also, both chemical crosslinking and radiation crosslinking may be carried out.

[0092] When carrying out the chemical crosslinking, it is preferable to use a crosslinking agent (use the present composition containing the crosslinking agent). As the crosslinking agent, conventionally known crosslinking agents 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, this composition preferably 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 etc.

[0093] 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.

[0094] As the radiation crosslinking, electron beam crosslinking is preferable. When performing the radiation crosslinking, a crosslinking agent may or may not be used. When irradiating with an electron beam, it is desirable to perform the irradiation so that the absorbed dose is preferably 0.5 to 100 kGy, more preferably 0.5 to 70 kGy. In addition, 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 performed a plurality of times.

[0095] When crosslinking this composition, it is preferable to mold this composition into a desired shape (produce a molded body) and crosslink the molded body. The preparation, molding, and crosslinking of this composition may be performed separately or continuously.

[0096] The composition may be crosslinked in a state of a laminate in which a sheet containing the composition and a release sheet are laminated. Examples of the method for producing a laminate in which a sheet containing the composition and a release sheet are laminated include a method of sandwiching the composition between two release sheets and performing pressing using a hot press device and a cooling press device, and a method of extrusion laminating the release sheet and the composition in the order of release sheet / sheet containing the composition / release sheet. When the laminate is produced by sandwiching the present composition between two release sheets and performing pressing using a hot press device and a cooling press device, the adhesion between the sheet containing the present composition and the release sheet is improved, so that the release sheet is less likely to peel off when the laminate is produced and carried. Preferably, the laminate includes a release sheet / a sheet containing the present composition / a release sheet in this order.

[0097] In the state of a laminate in which a sheet containing the present composition and a release sheet are laminated, by crosslinking the present composition, a laminate in which a sheet containing a crosslinked product and a release sheet are laminated can be obtained. The release sheet is preferably a polyester sheet, more preferably a polyethylene terephthalate sheet. When the release sheet is a polyester sheet, in the laminate, when the sheet containing the crosslinked product is peeled off from the release sheet to obtain a crosslinked sheet, the crosslinked sheet is less likely to tear. In the laminate, the sheet containing the present composition and the release sheet are preferably laminated adjacent to each other. When the sheet containing the present composition and the release sheet are laminated adjacent to each other, after crosslinking the present composition in the state of the laminate, the sheet containing the crosslinked product can be easily peeled off from the release sheet.

[0098] ≪Molded article≫ The molded article according to the present invention contains the present composition or the crosslinked product. From the viewpoints of handleability and workability, etc., after being molded into a desired shape, it is preferably used for a desired application. According to the present composition, a molded article having a desired shape can be easily formed. The above-mentioned molded body is suitably used for heat dissipation of electronic devices and components that generate heat (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 suitably used as a TIM such as a heat dissipation sheet. In particular, since the molded body has excellent thermal conductivity, it is suitably used as a TIM for improving the thermal conductivity between a heat-generating body and a heat dissipation member, and between heat dissipation members. Since the molded body also has excellent heat resistance, it is suitably used for heat-generating bodies and heat dissipation members that can reach high temperatures. Furthermore, since the molded body has excellent insulation properties, it is also suitably used for applications that require insulation, such as an alternative material for insulating paper, and an insulating coating material (coating layer) for electric wires or cables used in motor wires, etc. Also, the molded body can be used for a part of the housing of various electronic devices such as notebook computers and mobile devices, and 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 a method of installing a plurality of resin injection gates in a mold for molding the housing and injecting resins with different compositions for each gate.

[0099] In addition to the above applications, the above-mentioned molded body is also used for, for example, architectural applications such as building materials, and clothing applications. Also, the molded body is suitable as a filament for a 3D printer by utilizing its warm and cold feeling and moldability.

[0100] Examples of the molded body include a sheet, and particularly a heat dissipation and insulation sheet. 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.

[0101] As a molding method for obtaining the molded article from the present composition, a conventionally known method can be used. Examples of the molding method include an extrusion molding method, an inflation method, a vacuum / compression molding method, a calender molding method, and an injection molding method.

[0102] As a method for producing a sheet as a molded article from the present composition, for example, a method of sandwiching the present composition between two release sheets, performing hot pressing and cooling pressing to produce a laminate in which the release sheets and the sheet containing the present composition are laminated, and then peeling the sheet containing the present composition from the release sheet can be mentioned. As a method for producing a crosslinked sheet as a molded article from the present composition, for example, a method of sandwiching the present composition between two release sheets, performing hot pressing and cooling pressing to produce a laminate in which the release sheets and the sheet containing the present composition are laminated, then crosslinking the present composition in the state of the laminate, and then peeling the sheet containing the crosslinked present composition from the release sheet can be mentioned. When producing a sheet or a crosslinked sheet by such a method, the sheet or the crosslinked sheet can be easily made thinner compared to other production methods.

Examples

[0103] Hereinafter, the present invention will be described more specifically based on examples, but the present invention is not limited to these examples.

[0104] As the ethylene-α-olefin copolymer (A1), the following copolymer (A1-1) was used, and as comparative copolymers, the following copolymers (A1'-2) and (A1'-3) were 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) · "Copolymer (A1'-2)": Ethylene-1-butene copolymer (density = 885 kg / m 3 , MFR (190 °C, 2.16 kg load) = 3.6 g / 10 min, melting point = 66 °C, Shore A hardness = 86) · "Copolymer (A1'-3)": Ethylene-1-butene copolymer (density = 870 kg / m 3 , MFR (190 °C, 2.16 kg load) = 35 g / 10 min, melting point = 55 °C, Shore A hardness = 70)

[0105] As the acid-modified ethylene-α-olefin copolymer (A2), the following copolymer (A2-1) was used, and as the comparative copolymer, the following copolymer (A2'-2) 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) · "Copolymer (A2'-2)": Ethylene-vinyl acetate copolymer (970 kg / m 3 , MFR (190 °C, 2.16 kg load) = 2 g / 10 min, melting point = 40 °C)

[0106] 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)

[0107] <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)

[0108] <Release sheet> As the release sheet, the following commercially available protective sheets were used. · "A3E" (manufactured by Nippa Co., Ltd., PET sheet, with release agent, thickness = 38 μm, peel load = 40 mN, emboss pattern included (diamond shape))

[0109] [Examples 1 to 5 and Comparative Examples 1 to 10] [Preparation of Resin Composition] Each component described in Tables 1 to 2 below was put into a Laboplastmill (manufactured by Toyo Seiki Seisakusho Co., Ltd., model "30C150") so as to have the numerical values (parts by mass) described in Tables 1 to 2 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 resin composition.

[0110] [Preparation of Laminate (Thermal Press Sheet)] The prepared olefin resin composition was sandwiched between protective sheets (A3E) sized 200 mm × 200 mm × 38 μm (thickness) in the order of PET sheet / release agent / olefin resin composition / release agent / PET sheet, and a laminate (thermal press sheet) sized 150 mm × 150 mm was prepared using a hot press apparatus and a cooling press apparatus. The press conditions using the hot press apparatus and the press conditions using the cooling press apparatus were both a hydraulic pressure of 100 kgf / cm 2 , a press time of 5 minutes, and the temperature conditions when pressing using the hot press apparatus were as described in Tables 1 to 2. A part of the thermal press sheet obtained by this method was cut out, and the thickness of the sheet formed from the olefin resin composition obtained by peeling the protective sheet in the cut thermal press sheet was as described in Tables 1 to 2. When the thickness of the sheet formed from the olefin resin composition was 200 μm or less, a laminate (sheet for measuring physical properties) prepared in the same manner as the above-described method except that the press conditions were changed so that the thickness of the sheet formed from the olefin resin composition became 1 mm was also prepared in order to measure the physical property values described later.

[0111] [Preparation of Crosslinked Sheet] Using a batch conveyor (EPS-750, manufactured by NHV Corporation), the prepared hot press sheet and the sheet for measuring physical properties were irradiated with an electron beam of 20 kGy twice for the hot press sheet and eight times for the sheet for measuring physical properties, thereby crosslinking the olefin resin composition. 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.

[0112] [Evaluation] <Scratch on the surface of the device> After kneading the olefin resin composition with a lab plastomill, when wiping the surface of the lab plastomill with a wipe, 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 wipe. B: A very small amount of metal powder was attached to the wipe. C: Metal powder was attached to the wipe conspicuously.

[0113] <Possibility of sheet formation> When producing a hot press sheet with a hot press device and a cooling press device, it was evaluated as A when the olefin resin composition was spread out and formed into a sheet, and as B when the olefin resin composition was compatible with the protective sheet and not formed into a sheet.

[0114] <Tear when peeling off 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 attached to the protective sheet was evaluated according to the following criteria. A: No crosslinked body was attached to the protective sheet. B: The crosslinked body was attached at a ratio of less than 5% with respect to the area of the protective sheet. C: The crosslinked body was attached 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", and when the evaluation is C, it is said that "the crosslinked sheet tore".

[0115] <Heat resistance> Regarding the crosslinked sheet prepared from the sheet for measuring physical property values, as a solid viscoelasticity measuring device, RSA-III (manufactured by TA Instruments) was used, and 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 in a nitrogen atmosphere, the temperature at which the rubber plateau region continued was measured. The temperature at which the rubber plateau region continued was evaluated as level A when it reached 240 °C, the upper limit of the temperature range, and level B when it did not reach 240 °C.

[0116] <Thermal conductivity> Regarding the heat press sheet and the crosslinked sheet prepared 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 prepared 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, measurement was performed on the crosslinked sheet prepared from the heat press sheet. As the measuring device, a thermal diffusivity measuring device 1r (manufactured by Afez Co., Ltd.) was used. The results are shown in Tables 1 to 2. 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.

[0117] <Volume resistivity> Regarding the crosslinked sheet prepared from the heat press sheet, the volume resistivity was measured by a method conforming to ASTM D257:2007. The measuring device and measurement 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, measurement environment: 23 ± 2 °C · 50 ± 5% RH, applied voltage: 500 V, applied time: 60 seconds, discharge time: 5 seconds, number of tests: 3 times. The average value of the three measurements is shown in Tables 1 to 2. The volume resistivity is 1.0×10 14When it is 1 Ω·cm or more, it can be said that the crosslinked body has a sufficient volume resistivity.

[0118] <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 measurement conditions were as follows: ambient medium: silicone oil, power supply: AC 50 Hz, electrode: upper part is a cylindrical shape with a diameter of Φ25 mm, lower part is a copper plate of 100×100 mm, measurement temperature: 23±2°C, voltage increase rate: 1 kV / second, number of tests: 3 times. The average value of the three measurements is shown in Tables 1 to 2. When the dielectric breakdown strength is 30 kV / mm or more, it can be said that the crosslinked body has a sufficient dielectric breakdown strength.

[0119]

Table 1

[0120]

Table 2

[0121] When the total content of the ethylene·α-olefin copolymer (A1) and the acid-modified ethylene·α-olefin copolymer (A2) is less than 21 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 peeling the protective sheet to recover the crosslinked sheet, the crosslinked sheet was torn. (Comparative Examples 1 and 2). Also, when the content of the ethylene·α-olefin copolymer (A1) is 21 parts by mass or more and the acid-modified ethylene·α-olefin copolymer (A2) is not contained, when peeling the protective sheet to recover the crosslinked sheet, the crosslinked sheet was torn (Comparative Examples 3 to 5). On the other hand, when the total content of the ethylene-α-olefin copolymer (A1) and the acid-modified ethylene-α-olefin copolymer (A2) is 21 parts by mass or more with respect to 100 parts by mass in total of the ethylene-α-olefin copolymer (A1), the acid-modified ethylene-α-olefin copolymer (A2), and the ethylene-propylene copolymer (B), and the acid-modified ethylene-α-olefin copolymer (A2) is contained in an amount of 1 part by mass or more with respect to 100 parts by mass in total of the ethylene-α-olefin copolymer (A1) and the acid-modified ethylene-α-olefin copolymer (A2), it was found that the crosslinked sheet is less likely to be torn when peeling the protective sheet to recover the crosslinked sheet (Examples 1 and 2).

[0122] When the total content of the ethylene-α-olefin copolymer (A1) and the acid-modified ethylene-α-olefin copolymer (A2) exceeds 79 parts by mass with respect to 100 parts by mass in total of the ethylene-α-olefin copolymer (A1), the acid-modified ethylene-α-olefin copolymer (A2), and the ethylene-propylene copolymer (B), it was found that the surface of the kneading device is easily worn (Comparative Examples 5 and 6). Further, even when the total content of the ethylene-α-olefin copolymer (A1) and the acid-modified ethylene-α-olefin copolymer (A2) is 79 parts by mass or less with respect to 100 parts by mass in total of the ethylene-α-olefin copolymer (A1), the acid-modified ethylene-α-olefin copolymer (A2), and the ethylene-propylene copolymer (B), when the acid-modified ethylene-α-olefin copolymer (A2) is contained in an amount of more than 99 parts by mass with respect to 100 parts by mass in total of the ethylene-α-olefin copolymer (A1) and the acid-modified ethylene-α-olefin copolymer (A2), it was found that the surface of the kneading device is easily worn (Examples 5 and Comparative Example 7).

[0123] When the "MFR (190 °C, 2.16 kg load)" of the ethylene-α-olefin copolymer is less than 5 g / 10 minutes, since the fluidity of the resin composition is low, it was found that the filler cannot be spread and it is difficult to make the hot press sheet have a thickness of 200 μm or less (Comparative Example 8). Also, when the "Shore A hardness of the ethylene-α-olefin copolymer is less than 75", the heat press sheet can be made to a thickness of 200 μm or less, but when recovering the crosslinked sheet from the protective sheet, the crosslinked sheet was torn (Comparative Example 9). From the above, it was found that the ethylene-α-olefin copolymer (A1) needs to have "MFR (190 °C, 2.16 kg load) of 5 g / 10 min or more" and "Shore A hardness of 75 or more" (Example 3).

[0124] When the acid-modified ethylene-α-olefin copolymer does not satisfy "MFR (190 °C, 2.16 kg load) of 5 g / 10 min or more" and "melting point of 40 °C or more", the crosslinked sheet was torn when peeling the crosslinked sheet from the protective sheet and recovering it (Comparative Example 10). On the other hand, when the acid-modified ethylene-α-olefin copolymer has "MFR (190 °C, 2.16 kg load) of 5 g / 10 min or more" and "melting point of 40 °C or more", the crosslinked sheet was not torn when peeling the crosslinked sheet from the protective sheet and recovering it (Example 3).

Claims

1. An olefin resin composition comprising an ethylene-α-olefin copolymer (A1), an acid-modified ethylene-α-olefin copolymer (A2), an ethylene-propylene copolymer (B), and a nitride (C), wherein 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 [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; Olefin resin composition; 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 indentation needle contact in a sample in which 7 cross-linked sheets each having a thickness of 1 mm are stacked 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 a derivative thereof; 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.

2. The olefin resin composition according to claim 1, wherein the α-olefin that leads to the constitutional unit (ii) in the ethylene / α-olefin copolymer (A1) and / or the acid-modified ethylene / α-olefin copolymer (A2) is 1-butene.

3. The olefin resin composition according to claim 1, containing an ethylene / propylene copolymer (B) that satisfies the following requirement (B-1); Requirement (B-1): The Brookfield viscosity measured at 25°C is 100,000 to 300,000 mPa·s.

4. The olefin resin composition according to claim 1, wherein the nitride (C) is aluminum nitride (C1).

5. A crosslinked product obtained by crosslinking the olefin resin composition according to any one of claims 1 to 4.

6. A laminate in which a sheet containing the crosslinked product according to claim 5 and a release sheet are laminated.

7. The laminate according to claim 6, wherein the release sheet is a polyester sheet.

8. A molded article containing the olefin resin composition according to any one of claims 1 to 4.

9. A molded article containing the crosslinked product according to claim 5.

10. A sheet containing the crosslinked product according to claim 5.

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