Thermosoftening thermal conductive material

Abstract

Provided is a thermosoftening thermally-conductive member that is present as a solid during mounting on an electronic component, etc., and thus is excellent in handling properties, and that exhibits excellent thermal conductivity as a result of the thermal resistance being decreased due to the thermosoftening thermally-conductive member being softened by heat generation from the electronic component, etc.　The thermosoftening thermally-conductive member, which is sheet-shaped, has a composition layer comprising a thermoplastic silicone resin composition containing the following components (A)-(E). (A) Thermoplastic silicone resin (B) Spherical aluminum filler powder (C) Crushed zinc oxide filler powder (D) Surface preparation agent (E) Internal-additive release agent

Description

[Technical Field]

[0001] This invention relates to a thermo-softening, thermally conductive member. [Background technology]

[0002] In recent years, numerous thermally conductive materials have been proposed that possess both the handling characteristics of low-hardness thermally conductive sheets and the low thermal resistance of thermally conductive greases. These materials are solid at room temperature, making them easy to handle, and they soften or melt due to the heat generated by electronic components. Silicone is a material that is particularly excellent in heat resistance, weather resistance, and flame retardancy, and many thermosoftening materials based on silicone have been proposed. For example, a composition containing a thermoplastic silicone resin, a waxy modified silicone resin, and a thermally conductive filler has been proposed (Patent Document 1). Furthermore, a thermally conductive sheet containing a binder resin such as silicone gel, wax, and a thermally conductive filler has been proposed (Patent Document 2). Furthermore, a heat-softening heat-dissipating sheet has been proposed using a composition containing a polymer gel such as silicone, a compound that becomes liquid when heated, such as modified silicone or wax, and a thermally conductive filler (Patent Document 3). However, because these use organic substances such as wax or silicone-modified wax in addition to silicone, they have the disadvantage of being less flame-retardant and heat-resistant than silicone alone. As a countermeasure, a heat dissipation member has been proposed that includes a thermoplastic silicone resin with excellent flame retardancy and heat resistance, and a thermally conductive filler (Patent Document 4). However, this heat dissipation member also has the drawback of high thermal resistance. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2000-327917 [Patent Document 2] Japanese Patent Publication No. 2001-291807 [Patent Document 3] Japanese Patent Application Laid-Open No. 2002-234952 [Patent Document 4] International Publication No. 2002 / 091465 [Summary of the Invention] [Problems to be Solved by the Invention]

[0004] Therefore, an object of the present invention is to provide a heat-softening heat-conductive member that is solid and has excellent handleability when mounted on electronic components and the like, softens due to heat generated from the electronic components and the like to reduce thermal resistance, and as a result, exhibits excellent heat conductivity. [Means for Solving the Problems]

[0005] As a result of intensive studies by the present inventor, it is possible to form into a desired shape such as a sheet in a solid state at room temperature (25°C), it is easy to mount and demount on electronic components and heat sinks, softens with the heat generated during the operation of the electronic components, exhibits excellent heat conductivity by reducing thermal resistance, is excellent in flame retardancy, heat resistance, weather resistance, and furthermore, has excellent handleability. The present inventor has found a heat-softening heat-conductive member and completed the present invention. That is, the present invention provides the following heat-softening heat-conductive members.

[0006] [1] A sheet-like heat-softening heat-conductive member having a composition layer made of a thermoplastic silicone resin composition containing the following components (A) to (E). (A) R 2 / 2 , 3 / 2 , , , 1 , 1 , 1 , SiO 3 / 2 Unit (T unit) and R 1 2SiO 2 / 2 Unit (D unit) (in each formula, R 1 is independently a monovalent hydrocarbon group having 1 to 10 carbon atoms): 100 parts by mass (B) Spherical aluminum filler powder containing the following (B-1) and (B-2): 550 to 945 parts by mass (B-1) Spherical aluminum filler powder having an average particle diameter exceeding 6 μm and not exceeding 17 μm: 400 to 600 parts by mass (B-2) Spherical aluminum filler powder with an average particle size exceeding 1.3 μm and being 6 μm or less: 150 to 350 parts by mass (C) Crushed zinc oxide filler powder with an average particle size exceeding 0.5 μm and being 3 μm or less: 100 to 200 parts by mass However, the total of component (B) and component (C) is 700 to 945 parts by mass (D) One or more surface treatment agents selected from the following (D-1) and (D-2): 4.0 to 15.0 parts by mass (D-1) An alkoxysilane compound represented by the following formula (1) R 2 a R 3 b Si(OR 4 ) 4-a-b (1) (In the formula, R 2 is independently an alkyl group having 6 to 15 carbon atoms, R 3 is independently a group selected from an alkyl group having 1 to 5 carbon atoms, an aryl group having 6 to 12 carbon atoms, and an aralkyl group having 7 to 12 carbon atoms, R 4 is independently an alkyl group having 1 to 6 carbon atoms, a is a number from 1 to 3, b is a number from 0 to 2, provided that a + b is a number from 1 to 3.) (D-2) Dimethylpolysiloxane having a trialkoxysilyl group blocking the molecular chain ends, represented by the following formula (2)

Chemical formula

Chemical formula

[0007] The heat-softening thermal conductive member of the present invention is solid and easy to handle when attached to electronic components, has low thermal resistance and good thermal conductivity. By placing this heat-softening thermal conductive member between a heat-generating electronic component and a heat-dissipating component, the heat generated from the heat-generating electronic component can be efficiently dissipated to the heat-dissipating component. Therefore, it is possible to significantly improve the lifespan of heat-generating electronic components and electronic devices using them. [Brief explanation of the drawing]

[0008] [Figure 1] This is a front view showing the product form of the heat-softening, heat-conductive member of the present invention. [Figure 2] This is a side view showing the product form of the heat-softening, heat-conductive member of the present invention. [Modes for carrying out the invention]

[0009] The present invention will be described in more detail below.

[0010] [(A) Thermoplastic silicone resin] The thermoplastic silicone resin of component (A) used in this invention is R 1 SiO 3 / 2 Units (hereinafter referred to as T units) and R 1 2SiO 2 / 2The present invention is characterized by containing a unit (hereinafter referred to as D unit). The aforementioned (A) component serves as the medium (matrix) of the thermosoftening thermal conductive member of the present invention. While this (A) component is one factor that causes thermosoftening, it also plays a role as a binder that provides processability and workability to the thermal conductive filler that imparts thermal conductivity.

[0011] Here, the above R 1 This is a monovalent hydrocarbon group having 1 to 10 carbon atoms, preferably 1 to 6 carbon atoms. 1 Specific examples include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, and cyclohexyl groups, aryl groups such as phenyl groups, vinyl, allyl, propenyl, isopropenyl, butenyl, hexenyl, and cyclohexenyl groups, and other alkenyl groups. Among these, R 1 Methyl groups, phenyl groups, and vinyl groups are particularly preferred.

[0012] Furthermore, the thermoplastic silicone resin of component (A) contains T units and D units. In particular, T units are effective in improving brittleness in the solid state and providing excellent toughness to prevent breakage during handling. Here, substituents (R) of the T units 1 ) Preferably, the substituents are methyl and phenyl groups, and D units (R 1 The preferred members are methyl groups, phenyl groups, and vinyl groups. The ratio of T units to D units is preferably 10:90 to 90:10, and particularly preferably 20:80 to 80:20.

[0013] As described above, the thermoplastic silicone resin is solid at room temperature (25°C), and its viscosity should decrease to some extent when softened by heat. It also needs to be able to act as a binder for the thermally conductive fillers of components (B) and (C) described later. The weight-average molecular weight of this thermoplastic silicone resin is preferably 500 to 20,000, and particularly preferably 1,000 to 10,000. If the weight-average molecular weight of the thermoplastic silicone resin is less than 500, the viscosity during thermal softening will be too low, which may cause pumping out due to heat cycling. Conversely, if it exceeds 20,000, the viscosity during thermal softening will be too high, which may reduce adhesion to electronic components and heat dissipation components. In this invention, the weight-average molecular weight refers to the weight-average molecular weight measured using gel permeation chromatography (GPC) with polystyrene as the standard substance, under the following conditions. [Measurement conditions] Developing solvent: Tetrahydrofuran (THF) Flow rate: 0.6mL / min Detector: Differential refractive index detector (RI) Column: TSK Guardcolumn SuperH-L TSKgel SuperH4000(6.0mmI.D.×15cm×1) TSKgel SuperH3000(6.0mmI.D.×15cm×1) TSKgel SuperH2000(6.0mmI.D.×15cm×2) (All manufactured by Tosoh Corporation) Column temperature: 40℃ Sample injection volume: 20 μL (0.5 wt% THF solution)

[0014] Furthermore, the thermoplastic silicone resin used in the present invention is preferably one that imparts flexibility and tackiness to the thermally conductive member of the present invention. The thermoplastic silicone resin may be a polymer with a single molecular weight, or it may be a mixture of two or more polymers with different molecular weights.

[0015] [(B) Spherical aluminum filler powder] The average particle size of the spherical aluminum filler powder of component (B-1) is in the range of more than 6 μm and 17 μm or less, preferably in the range of 10 to 16 μm. If the average particle size is greater than 17 μm, the resulting material will be non-uniform, and the thickness will not decrease even when pressurized during thermal softening, resulting in reduced thermal conductivity. The amount added is 400 to 600 parts by mass, preferably 450 to 550 parts by mass, per 100 parts by mass of component (A). If the amount of component (B-1) is less than 400 parts by mass, the thermal conductivity will decrease, which is undesirable, and if it exceeds 600 parts by mass, the flexibility of the sheet will deteriorate, which is also undesirable. The average particle size of the spherical aluminum filler powder of component (B-2) is in the range of more than 1.3 μm and 6 μm or less, preferably in the range of 1.7 to 5 μm. If the average particle size is 1.3 μm or less, it becomes difficult to fill the silicone resin to a high degree, making it impossible to improve thermal conductivity, and the fluidity of the material when it is heated becomes poor. The amount added is 150 to 350 parts by mass, preferably 200 to 300 parts by mass, per 100 parts by mass of component (A). If the amount of component (B-2) is less than 150 parts by mass, the thermal conductivity will decrease, which is undesirable, and if it exceeds 350 parts by mass, the flexibility of the sheet will deteriorate, which is also undesirable. Furthermore, the total amount of components (B-1) and (B-2) must be 550 to 945 parts by mass, preferably 650 to 800 parts by mass, relative to 100 parts by mass of component (A). Furthermore, in this specification, "average particle size" refers to the volume-average particle size measured by laser diffraction / scattering.

[0016] [(C) Crushed zinc oxide filler powder] The average particle size of the crushed zinc oxide filler powder of component (C) is greater than 0.5 μm and less than or equal to 3 μm, preferably in the range of 0.6 to 2 μm. If the average particle size is less than 0.5 μm, the fluidity of the material during thermal softening will be poor, and if it is greater than 3 μm, the filling efficiency when combined with aluminum filler powder may be poor. By using crushed zinc oxide filler powder, the thermal conductivity can be increased compared to spherical zinc oxide filler powder. The amount added is 100 to 200 parts by mass, preferably 100 to 170 parts by mass, per 100 parts by mass of component (A). If the amount of component (C) is less than 100 parts by mass, the composition becomes difficult to handle, which is undesirable, and if it exceeds 200 parts by mass, the fluidity of the composition decreases, which is also undesirable.

[0017] The thermally conductive filler used in the present invention is obtained by combining two types of spherical aluminum filler powder, which are component (B), and crushed zinc oxide filler powder, which is component (C), and blending them with a thermoplastic silicone resin, which is component (A), to impart thermal conductivity to the component of the present invention.

[0018] The thermal conductivity of aluminum (component B) and zinc oxide (component C) are approximately 237 W / mK and 20 W / mK, respectively, and aluminum alone is advantageous in obtaining higher thermal conductivity. However, using aluminum filler powder alone results in a composition that is somewhat difficult to handle and has higher thermal resistance. After various studies, the inventors found that this problem can be solved by using zinc oxide filler powder in combination with aluminum filler powder.

[0019] The total amount of components (B) and (C) is 700 to 945 parts by mass, preferably 800 to 900 parts by mass, relative to 100 parts by mass of component (A). If the amount is less than 700 parts by mass, the resulting composition will have poor thermal conductivity, and if it is more than 945 parts by mass, the handling properties will decrease, and the fluidity during thermal softening may be poor. Furthermore, the mass ratio (B) / (C) of the amounts of component (B) to component (C) is preferably in the range of 1 to 10, and more preferably in the range of 2 to 6. If this mass ratio is less than 1, the resulting composition will have poor thermal conductivity, and if it is greater than 10, it may not be possible to solve the aforementioned problem (the handling properties of the resulting composition will be slightly reduced, and the thermal resistance will be higher).

[0020] [(D) Alkoxysilane compounds] The component (D) used in this invention is a surface treatment agent that improves the wettability between the thermally conductive filler, which is component (B) and (C), and the thermoplastic silicone resin, which is component (A). This component (D) is (D-1) and / or (D-2) below.

[0021] (D-1) Component Component (D-1) is an alkoxysilane compound represented by the following formula (1). R 2 a R 3 b Si(OR 4 ) 4-a-b (1) (In the formula, R 2 R is an alkyl group having 6 to 15 carbon atoms, 3 R is a group independently selected from alkyl groups having 1 to 5 carbon atoms, aryl groups having 6 to 12 carbon atoms, and aralkyl groups having 7 to 12 carbon atoms. 4 (where a is an alkyl group having 1 to 6 carbon atoms, a is a number from 1 to 3, b is a number from 0 to 2, and a+b is a number from 1 to 3.)

[0022] In formula (1), R 2 These are independently alkyl groups having 6 to 15 carbon atoms, preferably 8 to 13. Specifically, examples include hexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl groups, with decyl being preferred. In formula (1), R 3 The group is independently selected from alkyl groups having 1 to 5 carbon atoms, aryl groups having 6 to 12 carbon atoms, and aralkyl groups having 7 to 12 carbon atoms. Specifically, examples include alkyl groups such as methyl, ethyl, propyl, butyl, and pentyl groups, aryl groups such as phenyl, tolyl, and xyl groups, and aralkyl groups such as benzyl and 2-phenylethyl groups, with methyl and phenyl groups being preferred. In formula (1), R 4These are independently alkyl groups having 1 to 6 carbon atoms. Specifically, examples include methyl, ethyl, propyl, butyl, pentyl, hexyl, and cyclohexyl groups, with methyl being preferred. In formula (1), a is a number from 1 to 3, preferably 1 or 2, and b is a number from 0 to 2, preferably 0 or 1, provided that a+b is a number from 1 to 3, preferably 1 or 2.

[0023] (D-2) Component Component (D-2) is a dimethylpolysiloxane in which the ends of the molecular chain fragments represented by the following formula (2) are sealed with trialkoxysilyl groups. [ka] (R in the formula 5 (Each is an alkyl group with 1 to 6 carbon atoms, and c is a number between 5 and 100.)

[0024] In formula (2), R 5 These are independently alkyl groups having 1 to 6 carbon atoms. Specifically, examples include methyl, ethyl, propyl, butyl, pentyl, hexyl, and cyclohexyl groups, with methyl being preferred. In formula (2), c is a number between 5 and 100, preferably between 6 and 20.

[0025] The aforementioned components (D-1) and (D-2) may be used individually or in combination.

[0026] The amount of component (D) added is in the range of 4.0 to 15.0 parts by mass, preferably 5.0 to 12 parts by mass, relative to 100 parts by mass of component (A). If the amount of this surface treatment agent added is less than 4.0 parts by mass, the wettability of the thermally conductive filler will be poor and workability will decrease, and if the amount is greater than 15.0 parts by mass, the effect will not increase and it may be disadvantageous in terms of cost.

[0027] [(E) Internally added release agent] The component (E) used in this invention is an internal release agent, and is a silicone oil having a diphenylsiloxy group represented by the following formula (3). [ka] (In the formula, m is a number between 1 and 15, n is a number between 1 and 30, and m+n is a number satisfying 1 ≤ m+n ≤ 45. The bonding state of the diphenylsiloxy unit and dimethylsiloxy unit may be either block or random.)

[0028] In formula (3) above, m is 1 to 15, preferably 2 to 10. Also, n is 1 to 30, preferably 5 to 20. However, m and n are numbers that satisfy 1 ≤ m + n ≤ 45, and preferably 7 ≤ m + n ≤ 25.

[0029] The amount of component (E) added is 1.5 to 15 parts by mass, preferably 4 to 12 parts by mass, per 100 parts by mass of component (A).

[0030] The thermoplastic silicone resin composition constituting the composition layer of the heat-softening, heat-conductive member of the present invention may further use additives or fillers commonly used in synthetic rubber as optional components, to the extent that they do not impair the objectives of the present invention. Specifically, examples include fluorine-modified silicone surfactants as mold release agents, carbon black, titanium dioxide, red iron oxide, etc. as colorants, platinum catalysts, metal oxides or metal hydroxides such as iron oxide, titanium dioxide, and cerium oxide as flame retardants, and process oils, reactive silanes, or siloxanes as processability improvers. Furthermore, silica fine powder such as precipitated silica or calcined silica, thixotropic agents, etc., may be added as separation inhibitors at high temperatures.

[0031] The thermoplastic silicone resin composition constituting the composition layer of the heat-softening, heat-conductive member of the present invention can be easily manufactured by kneading the above-mentioned components using a mixer such as a dough mixer (kneader), gate mixer, or planetary mixer.

[0032] The thermoplastic silicone resin composition is typically molded into a sheet and used in the thermosoftening thermal conductive member of the present invention. Methods for molding into a sheet include extrusion molding, calender roll molding, and press molding of the thermosoftening thermal conductive material. Coating molding may also be performed using a solution of the thermoplastic silicone resin composition in an organic solvent. The heat-softening, heat-conductive member of the present invention has a composition layer (sheet) made of a thermoplastic silicone resin composition obtained in this manner. The thickness of this composition layer (sheet) is preferably in the range of 50 to 500 μm, and particularly in the range of 100 to 250 μm. If the thickness of the composition layer (sheet) is less than 50 μm, it is not possible to fill in the fine irregularities on the surface of heat-generating electronic components and heat dissipation components, resulting in high thermal resistance, and if it exceeds 500 μm, thermal conductivity may deteriorate.

[0033] From the viewpoint of ease of handling, the heat-softening, heat-conductive member of the present invention may have separator films on both sides of the composition layer made of the thermoplastic silicone resin composition. Preferably, the two separator films on both sides of the composition layer have different peeling forces.

[0034] Furthermore, the heat-softening thermal conductive member of the present invention can be used in the form shown in Figures 1 and 2 to improve handling (workability). Figure 1 shows a front view of one embodiment of the heat-softening thermal conductive member 10 of the present invention, and Figure 2 shows a side view. Separator film 1 is a continuous tape-shaped separator film with a relatively small peeling force (light peeling). Separator film 2 is a separator film cut to a certain size and has a greater peeling force than separator film 1 (heavy peeling). A composition layer 3 made of the thermoplastic silicone resin composition, cut to the same shape as separator film 2, is continuously arranged between the continuous tape-shaped separator film 1 and the separator film 2. In addition, a pull tab tape 4 is arranged on a part of the upper surface of separator film 2 (the surface not in contact with the composition layer).

[0035] In terms of usage, by pulling up the pull tab tape 4 attached to the separator film 2, the composition layer 3 made of thermoplastic silicone resin composition peels off from the separator film 1 and moves to the separator film 2 side. Furthermore, by attaching the surface of this composition layer 3 made of thermoplastic silicone resin composition to a heat-generating electronic component or heat dissipation component, and then pulling up the pull tab tape 4 to peel off the separator film 2, the composition layer 3 made of thermoplastic silicone resin composition can be easily installed in the desired location. As the release-side separator film, a light-release type separator film made by applying a silicone release treatment to a PET substrate can be used. As the substrate-side separator film, a double-peel type film made by applying a silicone release treatment to a PET substrate can be used. [Examples]

[0036] [Examples 1-5 and Comparative Examples 1-5] The present invention will be described in more detail below with reference to examples, but the present invention is not limited thereto. The following components were prepared to constitute the thermosoftening, thermally conductive member of the present invention.

[0037] (A) Component: Thermoplastic silicone resin A-1:D 25 TΦ 55 D Vi 20 (Weight average molecular weight 3,300, softening point: 40~50℃) However, D is Me2SiO 2 / 2 TΦ is PhSiO 3 / 2 , D Vi is ViMeSiO 2 / 2 Me represents a methyl group, and Vi represents a vinyl group. Their respective ratios are expressed in mole percent.

[0038] (B) Ingredients: Spherical aluminum filler powder B-1: Spherical aluminum filler powder with an average particle size of 11.5 μm B-2: Spherical aluminum filler powder with an average particle size of 3.8 μm

[0039] (C) Ingredients: Crushed zinc oxide filler powder C-1: Crushed zinc oxide filler powder with an average particle size of 1.5 μm

[0040] (D) Component: Alkoxysilane compound D-1: Decyltrimethoxysilane (KBM-3103C) D-2: Dimethylpolysiloxane in which the molecular chain ends, represented by the following formula, are sealed with trialkoxysilyl groups. [ka]

[0041] (E) Ingredients: Internally added release agent E-1: Phenyl group-containing internal release agent: Phenyl group-containing silicone oil represented by the following formula, with a viscosity of 0.4 Pa·s at 25°C. [ka]

[0042] Method for manufacturing a thermosoftening thermal conductive material Component (A) thermoplastic silicone resin, components (D) and (E) were placed in a planetary mixer according to the proportions shown in Table 1, and stirred and mixed at 25°C for 20 minutes to obtain a homogeneous liquid mixture. Next, component (B) aluminum filler powder and component (C) zinc oxide filler powder were added to this mixture according to the proportions shown in Table 1, and stirred and mixed at 25°C for 1 hour. 16 parts by mass of toluene were added to 100 parts by mass of the resulting composition solution to dilute it, and then it was coated onto a heavy-release separator film 2 made of PET (polyethylene terephthalate). Next, the toluene was evaporated in a drying oven at 80°C for 30 minutes, and then a light-release separator film 1 made of PET was pressed and laminated onto the composition layer using a hot roll at 90°C. The finished thickness of the composition layer was 250 μm. Furthermore, a portion of the pull tab tape 4 was laminated to the top of the heavily peelable separator film 2 so that it overlapped, and the pull tab tape 4, separator film 2, and composition layer 3 were cut to a width of 15 mm. The lightly peelable separator film 1 was left in tape form to obtain the product form (heat-softening thermal conductive member 10) shown in Figures 1 and 2.

[0043] Evaluation method (1) Thickness and thermal resistance of a heat-softening thermal conductive member when heated and compressed. The above composition layer 3 was sandwiched between two standard aluminum plates and heated at 90°C for 60 minutes under a pressure of 0.21 MPa. Next, the thickness of each of the two standard aluminum plates was measured, and the effective sheet thickness was determined by subtracting the thickness of the standard aluminum plate, whose thickness was known beforehand. A micrometer (Mitutoyo Corporation, model: M820-25VA) was used for thickness measurement. The thermal resistance (mm²) of the thermosoftening thermal conductive material was also measured. 2 The kW (K / W) was measured using a laser flash measuring instrument (manufactured by NETZSCH). The results are shown in Table 1.

[0044] (2) Softening point The softening temperature of Vicat was measured according to the Vicat softening temperature test method described in JIS K 7206:2016. The results are shown in Table 1.

[0045] (3) Hardness The thermally conductive silicone compositions obtained in Examples 1-5 and Comparative Examples 1-5 were cured at 90°C, then stacked to form 6mm thick sheets. Two of these sheets were stacked and measured using an Asker C hardness tester. The results are shown in Table 1.

[0046] (4) Adhesion between the separator film and the heat-softening heat-conducting member The heat-softening, heat-conductive member 10 was bent, and the adhesion between the composition layer 3, made of a thermoplastic silicone resin composition, and the easily peelable separator film 1 was visually evaluated. The results are shown in Table 1. A: Very good B: Good C: Slight peeling present D: Peeling present

[0047] [Table 1] [Explanation of Symbols]

[0048] 1: Lightly peelable separator film 2: Double-peel separator film 3: Composition layer made of thermoplastic silicone resin composition 4: Pull tab tape 10: Thermosoftening thermal conductive material

Claims

1. A sheet-like, thermosoft, and heat-conductive member having a composition layer made of a thermoplastic silicone resin composition containing the following components (A) to (E). (A)R 1 SiO 3 / 2 Units (T units) and R 1 2 SiO 2 / 2 Units (D units) (R in each formula) 1 Thermoplastic silicone resin containing (a monovalent hydrocarbon group having 1 to 10 carbon atoms independently): 100 parts by mass (B) Spherical aluminum filler powder containing (B-1) and (B-2) below: 550 to 945 parts by mass (B-1) Spherical aluminum filler powder with an average particle size of 10 to 16 μm: 400 to 600 parts by mass (B-2) Spherical aluminum filler powder with an average particle size of 1.7 to 5 μm: 150 to 350 parts by mass (C) Crushed zinc oxide filler powder with an average particle size greater than 0.5 μm and less than or equal to 3 μm: 100 to 200 parts by mass However, the total of component (B) and component (C) is 700 to 945 parts by mass. (D) One or more surface treatment agents selected from (D-1) and (D-2) below: 4.0 to 15.0 parts by mass (D-1) Alkoxysilane compounds represented by the following formula (1) R 2 a R 3 b Si(OR 4 ) 4-a-b (1) (In the formula, R 2 R is an alkyl group having 6 to 15 carbon atoms, 3 R is a group independently selected from alkyl groups having 1 to 5 carbon atoms, aryl groups having 6 to 12 carbon atoms, and aralkyl groups having 7 to 12 carbon atoms. 4 (where a is an alkyl group having 1 to 6 carbon atoms, a is a number from 1 to 3, b is a number from 0 to 2, and a + b is a number from 1 to 3.) (D-2) Dimethylpolysiloxane in which the molecular chain ends represented by the following formula (2) are sealed with trialkoxysilyl groups. 【Chemistry 1】 (In the formula R 5 (Each is an alkyl group having 1 to 6 carbon atoms, and c is a number from 5 to 100.) (E) Internal release agent represented by the following formula (3): 1.5 to 15 parts by mass 【Chemistry 2】 (In the formula, m is a number from 1 to 15, n is a number from 1 to 30, and m+n is a number satisfying 1 ≤ m+n ≤ 45. The bonding state of the diphenylsiloxy unit and the dimethylsiloxy unit may be block or random.)

2. The heat-softening thermal conductive member according to claim 1, wherein the thickness of the composition layer is 50 to 500 μm.

3. The heat-softening thermal conductive member according to claim 1, wherein the composition layer is in the form of a sheet with a thickness of 50 to 500 μm, and each side of the composition layer has two separator films with different peeling strengths.

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