Thermally conductive resin composition and molded article

Abstract

To provide a thermally conductive resin composition and a molded article that can be used as a heat dissipation material.SOLUTION: A thermally conductive resin composition according to the present disclosure comprises a polyvinyl chloride resin, a plasticizer, and brown fused alumina. The thermally conductive resin composition is, for example, a mixture comprising pulverized material of a carpet underlayer and brown fused alumina, and the pulverized material comprises a polyvinyl chloride resin and a plasticizer. A molded article according to the present disclosure is formed by molding the thermally conductive resin composition.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a thermally conductive resin composition and a molded article. [Background technology]

[0002] Patent Document 1 discloses a method for producing a composite recycled sheet using polyvinyl chloride resin as part of the raw materials. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-82802 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a thermally conductive resin composition that can be used as a heat dissipation material, and a molded article obtained by molding the thermally conductive resin composition. [Means for solving the problem]

[0005] The present disclosure relates to the following: [1] A thermally conductive resin composition comprising a polyvinyl chloride resin, a plasticizer, and brown fused alumina. [2] The thermally conductive resin composition according to [1], which is a mixture containing ground material of a carpet base layer and the brown fused alumina, wherein the ground material contains the polyvinyl chloride resin and the plasticizer. [3] The thermally conductive resin composition according to [1], which is a mixture containing ground carpet material and the brown fused alumina, wherein the ground material contains the polyvinyl chloride resin, the plasticizer, and fibers, and the fibers are at least one type of resin fiber selected from the group consisting of polyamide resin, polyolefin resin, and polyester resin. [4] The thermally conductive resin composition according to any one of [1] to [3], wherein the content of the brown fused alumina is 20 to 80 mass % based on the total mass of the thermally conductive resin composition. [5] The thermally conductive resin composition according to any one of [1] to [4], wherein the brown fused alumina has a particle size of F30 to F400. [6] A molded article obtained by molding the thermally conductive resin composition according to any one of [1] to [5]. [7] The molded product according to [6], which is in the form of a sheet having a thickness of 0.20 to 20 mm. [8] The molded article according to [6] or [7], which has a thermal conductivity of 0.8 W / m·K or more. [9] The molded article according to any one of [6] to [8], which has a tensile modulus of elasticity of 80 to 150 MPa. [Effects of the Invention]

[0006] According to the present disclosure, there is provided a thermally conductive resin composition that can be used as a heat dissipation material, and a molded article obtained by molding the thermally conductive resin composition. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a cross-sectional view schematically showing an example of a carpet. [Figure 2] FIG. 2 is a cross-sectional view schematically showing one embodiment of a molded article according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of the present disclosure will be described, but the invention is not limited to these embodiments.

[0009] The thermally conductive resin composition according to this embodiment contains polyvinyl chloride resin, a plasticizer, and brown fused alumina. A molded body made from this thermally conductive resin composition can be used as a heat dissipation material. Brown fused alumina is a type of alumina (Al2O3) and, as its name suggests, is brown in color. Brown fused alumina differs from ordinary white alumina in the following ways: (1) Raw materials and manufacturing process: Brown fused alumina is made from bauxite (a type of aluminum ore) through a process of melting the raw material at high temperatures. The iron (Fe2O3) contained in the bauxite mixes with the alumina, giving it its brown color. In contrast, white alumina is made from highly pure alumina raw materials and contains almost no iron, resulting in a white color. (2) Physical properties: Brown fused alumina has a sufficiently high hardness, but tends to be slightly softer than white alumina. (3) Chemical composition: Brown fused alumina contains impurities such as iron oxide (Fe2O3), titanium oxide (TiO2), and silica (SiO2) in addition to alumina. In contrast, white alumina has a very high alumina purity and contains only a small amount of impurities.

[0010] Although brown fused alumina contains more impurities than white alumina, it has excellent thermal conductivity, similar to white alumina. By adjusting the content of brown fused alumina in the thermally conductive resin composition, the thermal conductivity of the thermally conductive resin composition can be adjusted.

[0011] The Al2O3 content, based on the total amount of brown fused alumina, is, for example, 90.0 to 98.0 mass%. This value may be 92.0 mass% or more, 94.0 mass% or more, or 94.5 mass% or more, or 96.5 mass% or less, 96.0 mass% or less, or 95.0 mass% or less. When this value is 90.0 mass% or more, the brown fused alumina has sufficiently high toughness. When this value is 98.0 mass% or less, fracture and breakage of the brown fused alumina in a molded article obtained by molding the thermally conductive resin composition tends to be suppressed.

[0012] The Fe2O3 content, based on the total amount of brown fused alumina, is, for example, 0.1 to 4.0 mass%. This value may be 0.2 mass% or more, 0.4 mass% or more, or 0.5 mass% or more, and may be 3.0 mass% or less, 2.0 mass% or less, or 1.0 mass% or less. When this value is 0.1 mass% or more, fracture and breakage of the brown fused alumina in a molded article obtained by molding the thermally conductive resin composition tends to be suppressed. When this value is 4.0 mass% or less, the color tone of the brown fused alumina can be suppressed to a certain level, and the effect on the color of a molded article obtained using the thermally conductive resin composition can be suppressed.

[0013] The TiO content, based on the total amount of brown fused alumina, is, for example, 1.0 to 7.0 mass%. This value may be 1.25 mass% or more or 1.5 mass% or more, or may be 6.0 mass% or less, 5.0 mass% or less, or 4.0 mass% or less. When this value is 1.0 to 7.0 mass%, fracture and breakage of the brown fused alumina in a molded article obtained by molding the thermally conductive resin composition tends to be suppressed.

[0014] The SiO content, based on the total amount of brown fused alumina, is, for example, 0.5 to 5.0 mass%. This value may be 1.0 mass% or more, 1.25 mass% or more, or 1.5 mass% or more, and may be 4.0 mass% or less, 3.0 mass% or less, or 2.0 mass% or less. When this value is 0.5 to 5.0 mass%, fracture and breakage of the brown fused alumina in a molded article obtained by molding the thermally conductive resin composition tends to be suppressed.

[0015] The thermal conductivity of the thermally conductive resin composition is, for example, 0.8 W / m K or more. The thermal conductivity of the thermally conductive resin composition referred to here means the thermal conductivity determined by molding the thermally conductive resin composition into a sheet having a thickness of 1 mm and measuring it by a hot wire method.

[0016] The content of brown fused alumina is, for example, 20 to 80 mass% based on the total mass of the thermally conductive resin composition. This value may be 30 mass% or more, 40 mass% or more, or 50 mass% or more, and may be 75 mass% or less, 70 mass% or less, or 65 mass% or less. When this value is 20 to 80 mass%, the elastic modulus of a molded article obtained using the thermally conductive resin composition tends to be good.

[0017] The particle size of the brown fused alumina particles ranges, for example, from particle size F400 to particle size F30. The lower limit of the particle size may be particle size F320, F280, or F240. The upper limit of the particle size may be particle size F60, F100, or F150. A particle size equal to or greater than particle size F400 can suppress aggregation of the brown fused alumina particles, facilitating uniform properties of molded articles of the thermally conductive resin composition. A particle size equal to or less than particle size F30 can sufficiently increase the specific surface area of ​​the brown fused alumina, thereby increasing the number of contact points between the brown fused alumina particles and forming heat conduction paths, which tends to sufficiently improve the thermal conductivity of the thermally conductive resin composition. Note that, among the particle sizes referred to here, F400 to F230 are values ​​obtained in accordance with JIS R6001-2:2017, and F220 to F30 are values ​​obtained in accordance with JIS R6001-1:2017.

[0018] The particle shape of the brown fused alumina is not particularly limited. The cross-sectional shape of a brown fused alumina particle when cut at the center may be, for example, polygonal, circular, elliptical, or a combination thereof. Of the above shapes, polygonal is preferred. When the particle cross section is polygonal, the specific surface area of ​​the brown fused alumina can be increased, and the number of contact points between the brown fused alumina particles can be increased, thereby further improving the thermal conductivity of the thermally conductive resin composition.

[0019] The true specific gravity of the brown fused alumina may be, for example, 3.9 to 4.0, 3.92 to 3.97, or 3.93 to 3.95, and the bulk specific gravity may be, for example, 1.0 to 3.0, 1.5 to 2.5, or 1.9 to 2.0. When the true specific gravity or bulk specific gravity is within these ranges, the molded product tends to be appropriately lightweight.

[0020] Polyvinyl chloride resin is a resin synthesized by addition polymerization of monomers containing vinyl chloride (CH₂=CHCl). Polyvinyl chloride resin may be obtained by addition polymerization of only vinyl chloride monomer. Polyvinyl chloride resin is hard by itself, but can be softened by adding a plasticizer to polyvinyl chloride resin.

[0021] The content of the polyvinyl chloride resin is, for example, 3 to 80 mass% based on the total mass of the thermally conductive resin composition. When this value is 3 to 80 mass%, the dispersibility of the brown fused alumina in the thermally conductive resin composition tends to be good.

[0022] As the plasticizer, for example, monohydric alcohol esters such as phthalates and adipates, or polyhydric alcohol esters may be used. Phthalates include dioctyl phthalate (DOP), diisononyl phthalate (DINP), and diisodecyl phthalate (DIDP). Adipates include di-2-ethylhexyl adipate (DOA) and diisononyl adipate (DINA). Polyhydric alcohol esters include tri-2-ethylhexyl trimellitate (TOTM) and tricresyl phosphate (TCP).

[0023] The content of the plasticizer is, for example, 3 to 80 mass% based on the total mass of the thermally conductive resin composition. When this value is 3 to 80 mass% or less, the molding processability of the thermally conductive resin composition tends to be good.

[0024] The thermally conductive resin composition may further contain fibers. The fibers are at least one type of resin fiber selected from the group consisting of polyamide resin, polyolefin resin, and polyester resin. Examples of polyamide resin include nylon fibers such as nylon 6 and nylon 66. Examples of polyolefin resin include polypropylene and polyethylene. Examples of polyester resin include polyethylene terephthalate (PET). The fibers are preferably polypropylene or nylon fibers.

[0025] When the fibers are polypropylene or nylon, if the temperature during molding using the thermally conductive resin composition is similar to the melting point of these fibers, the fibers will have entangled points where they are thermally fused together in the molded product, and it is believed that the fibers in this state will function as a reinforcing material. On the other hand, if the kneading is performed at a temperature sufficiently higher than the melting point of the fibers, the fibers will melt, and if the resin other than the fibers has low compatibility with the fibers, it is believed that fiber aggregates will form in the molded product. Therefore, thermally conductive resin compositions containing these fibers have a high tensile modulus.

[0026] At least a portion of the fibers preferably has a length of 2 mm or more. This value may be 3 to 8 mm. When this value is 2 mm or more, the reinforcing effect of the fibers on the thermally conductive resin composition is more highly exhibited.

[0027] The fiber content is, for example, 1 to 20 mass% based on the total mass of the thermally conductive resin composition. When this value is 1 to 20 mass%, a molded article obtained by molding the thermally conductive resin composition tends to have an appropriate elastic modulus.

[0028] The thermally conductive resin composition may further contain a filler. Examples of the filler include calcium carbonate, magnesium carbonate, magnesium sulfate, barium sulfate, magnesium hydroxide, aluminum hydroxide, and glass powder. From the viewpoint of processability, the filler is preferably calcium carbonate.

[0029] The content of calcium carbonate is, for example, 5 to 80 mass % based on the total mass of the thermally conductive resin composition.

[0030] The thermally conductive resin composition preferably has a tensile modulus of 80 to 150 MPa. The lower limit of this value may be 90 MPa or 100 MPa. The upper limit of this value may be 135 MPa or 125 MPa. When this value is 80 to 150 MPa, a molded article obtained by molding the thermally conductive resin composition has appropriate flexibility and can be applied to various applications requiring flexibility. The tensile modulus of the thermally conductive resin composition can be adjusted by adjusting the contents of brown fused alumina, polyvinyl chloride resin, and plasticizer in the thermally conductive resin composition. Note that the tensile modulus of the thermally conductive resin composition referred to here refers to the tensile modulus calculated from the slope of the stress-strain line when the molded article has an elongation of 0.5% to 2.0% after a tensile test on a molded article having a length of 50 mm, a width of 4 mm, and a thickness of 1 mm, in an atmosphere of 23°C and 50% RH, with a chuck distance of 25 mm and a pulling rate of 5 mm / min.

[0031] The thermally conductive resin composition may contain ground material obtained from carpet as part of its raw material. Fig. 1 is a cross-sectional view schematically showing an example of a carpet. The carpet 10 shown in Fig. 1 includes a pile layer 1 made of pile yarns and a base layer 3 in which some of the pile yarns are embedded. The base layer 3 includes an intermediate layer 3a and a base layer 3b.

[0032] The thermally conductive resin composition may be, for example, a mixture of brown fused alumina and pulverized material of the entire carpet 10, or a mixture of brown fused alumina and pulverized material of a portion of the carpet 10. The portion of the carpet 10 may be, for example, the undercoat layer 3 (the intermediate layer 3a and the base layer 3b), or one of the intermediate layer 3a and the base layer 3b.

[0033] The pile layer 1 is composed of pile yarns made of a fibrous material. The pile yarns in this embodiment contain resin fibers, such as polyamide resin, polyolefin resin, or polyester resin. The pile layer 1 may also contain other synthetic fibers or natural fibers. Examples of synthetic fibers include acrylic fibers. Examples of natural fibers include linen, cotton, and wool. The pile layer 1 is formed, for example, by warp pile weaving or weft pile weaving. The pile layer 1 may be formed, for example, by implanting pile yarns using a tufting machine, or by adhering the pile yarns using an adhesive. The pile form may be either cut pile or loop pile. When the thermally conductive resin composition contains fibers derived from the pile layer 1, a molded product of the thermally conductive resin composition can exhibit a sufficient tensile modulus and excellent flexibility.

[0034] The intermediate layer 3a is sandwiched between the pile layer 1 and the base layer 3b. Some of the pile yarns are embedded in the intermediate layer 3a, which serves to fix the pile layer 1 and bond the pile layer 1 to the base layer 3b. The intermediate layer 3a is made of a composition containing polyvinyl chloride resin and a plasticizer, and contains resin fibers (e.g., PET fibers). The intermediate layer 3a may further contain the above-mentioned filler.

[0035] The base layer 3b forms the back surface of the carpet 10. The base layer 3b is made of a composition containing a polyvinyl chloride resin and a plasticizer. The plasticizer may be the same as that contained in the intermediate layer 3a. The base layer 3b may further contain the above-mentioned filler.

[0036] The crushed material obtained from the carpet preferably has a particle size of 10 mm or less (excluding crushed pile yarns). The particle size of the crushed material is more preferably 5 mm or less, and even more preferably 2 mm or less. A particle size of 2 mm or less makes the thermally conductive resin composition more uniform. This value may be, for example, 0.1 mm or more. A particle size of 0.1 mm or more tends to prevent the thermally conductive resin composition from becoming excessively bulky and reducing handleability. The particle size of the crushed material can be determined by preparing multiple sieves with different mesh sizes and determining whether the crushed material passes through the sieves.

[0037] From the viewpoint of effective utilization of waste, the carpet may be discarded, for example, discarded tile carpet.

[0038] By using offcuts generated during the manufacturing process or used materials discarded by ordinary households or offices as carpet tiles, these materials, which have traditionally been disposed of in landfills, can be effectively utilized. According to the above-described embodiment, a kneaded product in which thermal degradation is sufficiently suppressed can be obtained. Therefore, according to this embodiment, a recycling efficiency of, for example, 70% or more can be achieved. The recycling efficiency here refers to the ratio of the mass of waste (e.g., waste carpet tiles) to the total mass of the waste and virgin materials when producing a molded product. From the perspective of effective waste utilization, the recycling efficiency is preferably 80% or more, more preferably 90% or more, and even more preferably 100%.

[0039] The molded article according to the present disclosure is obtained by molding the thermally conductive resin composition, and can be used as a heat dissipation material.

[0040] The shape of the molded body may be a sheet, film, tube, cup, pellet, block, etc. The molded body is, for example, in the form of a sheet having a thickness of 0.2 to 20 mm. When the molded body is in the form of a sheet, the thickness of the sheet being 0.2 to 20 mm or less ensures that the molded body has appropriate flexibility and processability.

[0041] The thermal conductivity of the molded body is, for example, 0.8 W / m K or more. This value can be set appropriately depending on the application of the molded body and its thickness, shape, size, etc. The thermal conductivity of the molded body referred to here means the thermal conductivity determined by measuring the molded body using the hot wire method.

[0042] The tensile modulus of the molded article is preferably 80 to 150 MPa. The lower limit of this value may be 90 MPa or 100 MPa. The upper limit of this value may be 135 MPa or 125 MPa. When this value is 80 MPa to 150 MPa, the molded article can be used in a variety of applications requiring flexibility. The tensile modulus of the molded article can be adjusted by adjusting the contents of brown fused alumina, polyvinyl chloride resin, and plasticizer of the molded article. The tensile modulus of the molded article referred to here means the tensile modulus calculated from the slope of the stress-strain line when the molded article has an elongation of 0.5% to 2.0% after a tensile test on a molded article having a length of 50 mm and a width of 4 mm in an atmosphere of 23°C and 50% RH, with a chuck distance of 25 mm and a pulling rate of 5 mm / min.

[0043] 2 is a cross-sectional view schematically illustrating an example of a molded body 20 manufactured through a pressing process. The molded body 20 is composed of a matrix resin 5, fibers 7, and brown fused alumina particles 9. The matrix resin 5 contains a polyvinyl chloride resin and a plasticizer. The fibers 7 may be contained in a state in which they are thermally fused together, forming intertwined points. In this case, the reinforcing effect of the fibers 7 gives the molded body 20 a sufficiently high elastic modulus.

[0044] Hereinafter, methods for producing a thermally conductive resin composition and a molded article from a carpet will be described as an example. The method for producing a thermally conductive resin composition includes step (A) of preparing polyvinyl chloride resin, a plasticizer, and brown fused alumina as raw materials for the thermally conductive resin composition, and step (B) of mixing the prepared raw materials to obtain a thermally conductive resin composition. The method for producing a molded article includes step (C) of processing the thermally conductive resin composition into a molded article.

[0045] When carpet 10 is used as at least part of the raw material for the molded body, step (a1) of crushing carpet 10 may be carried out as part of step (A). In this case, crushed pieces of the entire carpet 10 may be used as at least part of the raw materials for the polyvinyl chloride resin and plasticizer. Crushed pieces of the base layer 3 or crushed pile yarns may be used as at least part of the raw materials.

[0046] In step (a1), the carpet 10 is crushed to prepare raw materials for the thermally conductive resin composition. The carpet 10 can be crushed using a known crushing device. A known crushing device can be used to pulverize the carpet 10 into powder. The carpet 10 is preferably crushed at an intensity and for a processing time that results in particle sizes of 10 mm or less (excluding crushed pile yarns). To prevent the fibers that make up the pile yarns from becoming excessively short due to crushing, the pile layer 1 and the base layer 3 can be separated before crushing the carpet 10, and the pile layer 1 can be crushed under different conditions than those for the base layer 3, as necessary.

[0047] The vinyl chloride resin and plasticizer used as raw materials may all be crushed carpet 10, or a portion may be crushed carpet 10 and used in combination with other materials. The other materials may include polyvinyl chloride resin, plasticizer, fibers, and fillers that are not derived from carpet. The amount of polyvinyl chloride resin to be added may be determined depending on the application and desired performance of the molded product.

[0048] The brown fused alumina used as a raw material may be obtained by synthesis from bauxite, or may be commercially available brown fused alumina particles.

[0049] In step (B), the raw materials are mixed to obtain a thermally conductive resin composition. The raw materials may be mixed using a known mixing device such as a blender.

[0050] In step (C), the thermally conductive resin composition is processed into a molded article. Step (C) may further include step (c1) of kneading the thermally conductive resin composition. The kneading temperature in step (c1) may be, for example, 141 to 280°C. The temperature may be 141 to 169°C, higher than 170°C and not higher than 280°C, 201 to 220°C, 221 to 245°C, 246 to 265°C, or 266 to 280°C. When the kneading temperature is 141 to 169°C, this temperature is close to the melting point of the polypropylene fibers. Therefore, in the molded article produced through step (C), the polypropylene fibers have intertwined points where the polypropylene fibers are thermally fused together, and it is presumed that the polypropylene fibers in this state serve as a reinforcing material. On the other hand, for example, if the kneading temperature in step (c1) is higher than 70°C and lower than 280°C, the polypropylene fibers melt, and especially if the polypropylene in the polypropylene fibers is not acid-modified or has low compatibility with other resins such as nylon, it is thought that polypropylene aggregates become mixed into the kneaded product. As a result, the molded product produced from this kneaded product has a high elastic modulus.

[0051] When the molded product is in the form of a sheet or film, it can be produced by a known plastic sheet molding method such as a calendar method or a T-die method. When the molded product is cylindrical (e.g., a tube), it can be produced by a known plastic molding method such as an extruder, a blow molding machine, or an injection molding machine. When the molded product is a block having a predetermined shape, it can be produced using a mold or an extruder. When producing a sheet-like molded product (e.g., 0.1 to 10 mm thick), it is preferable to complete the molded product by pressing the sheet during production under predetermined temperature and pressure conditions. The pressing temperature condition is preferably the same as the kneading temperature (141 to 280°C), and is preferably 141 to 169°C from the viewpoint of suppressing thermal degradation of the polyvinyl chloride resin. To obtain a molded product with a high elastic modulus, it is preferably 170 to 200°C, or may be 200 to 280°C. The pressing pressure condition is preferably 5 to 30 MPa, more preferably 10 to 20 MPa. Furthermore, parts with irregular shapes such as cups, bats, and bowls can be manufactured by known plastic molding methods such as injection molding machines and press molding machines.

[0052] A pressing temperature of 200°C or less can suppress thermal degradation of the polyvinyl chloride resin. When suppressing thermal degradation of the polyvinyl chloride resin is particularly important, the pressing temperature is preferably 169°C or less. On the other hand, when a high elastic modulus of the molded product is particularly important, the pressing temperature is preferably 170°C or more.

[0053] Although the embodiments of the present disclosure have been described in detail above, the present invention is not limited to the above embodiments. For example, although the above embodiments illustrate carpets having a two-layer base layer, the base layer may be a single layer or a laminated structure of three or more layers.

[0054] In the above embodiment, an example is given of a case where a molded article is produced from carpet, but the molded article is not limited to carpet and may be produced from a polyvinyl chloride resin or a product containing polyvinyl chloride resin and a plasticizer (for example, a flexible film, a tube, and an automobile interior / exterior component). [Example]

[0055] Hereinafter, the present disclosure will be described with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0056] <Ingredient preparation> (Crushed carpet tile A) A tile carpet having a pile layer, an intermediate layer, and a base layer in this order was prepared. The tile carpet was pulverized until the particle size was approximately 0.1 to 4 mm, to obtain pulverized material A. Table 1 shows the composition of pulverized material A.

[0057] (Crushed carpet tiles B) The base layer of the tile carpet was prepared by separating only the base layer from the tile carpet. The base layer was then pulverized to a particle size of approximately 0.1 to 4 mm to obtain pulverized material B. Table 1 shows the composition of pulverized material B.

[0058] [Table 1]

[0059] <Production of Sheet-Like Molded Product> Example 1 Mixture A was prepared by mixing 40 parts by mass of pulverized material A with 60 parts by mass of brown fused alumina particles (manufactured by Fuji Manufacturing Co., Ltd., product name: Fuji Random A, particle size F220). Mixture A was melt-kneaded using a Labo Plastomill (registered trademark) manufactured by Toyo Seiki Seisaku-sho, Ltd. to obtain resin composition A. The melt-kneading conditions were a blade rotation speed of 60 rpm, a temperature of 160°C, and a kneading time of 5 minutes. Resin composition A was then heat-pressed into a sheet with a thickness of 1 mm, to obtain a sheet-like molded product of Example 1. The heat-pressing conditions were a temperature of 160°C and a pressure of 5 MPa.

[0060] Example 2 A sheet-like formed product of Example 2 was obtained in the same manner as in Example 1, except that pulverized material B was used instead of pulverized material A.

[0061] (Comparative Example 1) A sheet-like formed product of Comparative Example 1 was obtained in the same manner as in Example 1, except that the pulverized material A was subjected to melt-kneading instead of the mixture A containing the pulverized material A and brown fused alumina particles.

[0062] (Comparative Example 2) A sheet-like molded product of Comparative Example 2 was obtained in the same manner as in Comparative Example 1, except that pulverized material B was used in place of pulverized material A for melt-kneading.

[0063] <Measurement of thermal conductivity> Test pieces measuring 100 mm in length and 50 mm in width were prepared by cutting out the sheet-like molded articles of the Examples and Comparative Examples. Thermal conductivity was measured by the hot wire method (JIS R2251-2 (parallel method)) using a rapid thermal conductivity meter (QTM-500, manufactured by Kyoto Electronics Manufacturing Co., Ltd.). The results are shown in Table 2.

[0064] <Measurement of tensile modulus> A plurality of test specimens were punched out from each of the sheet-like molded articles of the Examples and Comparative Examples. The test specimens were dumbbell-shaped No. 8 test specimens according to JIS K6251:2017. Tensile tests were conducted on the test specimens using a universal testing machine (Instron Japan Co., Ltd., Model 5582). The test conditions were an atmosphere of 23°C and 50% RH, a chuck distance of 25 mm, and a tensile speed of 5 mm / min. Three tensile tests were conducted for each Example and Comparative Example. The tensile modulus was calculated from the slope of the stress-strain line between elongations of 0.5% and 2%. The results are shown in Table 2.

[0065] [Table 2] [Explanation of symbols]

[0066] 1...pile layer, 3...base layer, 3a...intermediate layer, 3b...base material layer, 5...matrix resin, 7...fiber, 9...brown fused alumina particles, 10...carpet, 20...molded body.

Claims

1. A thermally conductive resin composition comprising a polyvinyl chloride resin, a plasticizer, and brown fused alumina.

2. a mixture containing ground material of a carpet base layer and the brown fused alumina, The thermally conductive resin composition according to claim 1 , wherein the pulverized material contains the polyvinyl chloride resin and the plasticizer.

3. a mixture containing ground carpet and the brown fused alumina, the pulverized material contains the polyvinyl chloride resin, the plasticizer, and fibers, 2. The thermally conductive resin composition according to claim 1, wherein the fibers are fibers of at least one resin selected from the group consisting of polyamide resins, polyolefin resins, and polyester resins.

4. 2. The thermally conductive resin composition according to claim 1, wherein the content of the brown fused alumina is 20 to 80 mass% based on the total mass of the thermally conductive resin composition.

5. 2. The thermally conductive resin composition according to claim 1, wherein the brown fused alumina has a particle size of F30 to F400.

6. A molded article obtained by molding the thermally conductive resin composition according to any one of claims 1 to 5.

7. The molded article according to claim 6, which is in the form of a sheet having a thickness of 0.2 to 20 mm.

8. The molded article according to claim 7, having a thermal conductivity of 0.8 W / m·K or more.

9. The molded article according to claim 7, having a tensile modulus of elasticity of 80 to 150 MPa.

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