Conductive thermoplastic resin composition, molded article, and method for manufacturing the same.

Abstract

To provide conductive thermoplastic resin compositions, molded articles, and methods for manufacturing the same, which have excellent conductivity and weather resistance, and a manufacturing method suitable for recycling polyvinyl chloride resin. [Solution] A conductive thermoplastic resin composition comprising polyvinyl chloride resin (A), aluminum fine particles (B) having an average particle diameter of 200 to 300 μm, and carbon black (C), wherein the total content of the aluminum fine particles (B) and the carbon black (C) is 43 to 60% by mass relative to 100% by mass of the conductive thermoplastic resin composition, and the content of the carbon black is 1 / 8 or less relative to the mass of the aluminum (B).

Description

Technical Field

[0001] The present invention relates to a resin composition excellent in conductivity and weather resistance, a molded body, and methods for producing them.

Background Art

[0002] Polyvinyl chloride resin has characteristics such as excellent chemical resistance, electrical properties, flame retardancy, durability, etc., and is generally inexpensive, so it is used in various applications as a general-purpose resin. For example, in Patent Document 1, it is disclosed that a composition obtained by containing aluminum in a resin such as polyolefin or double vinyl chloride copolymer at a content of 35 to 85% by mass and a molded body using the same are excellent in flame retardancy and thermal conductivity.

[0003] In Patent Document 2, it is disclosed that a film obtained by containing aluminum powder and carbon black in a vinyl chloride-based resin has high impact strength at low temperatures. Further, in Patent Document 3, it is disclosed that a composition obtained by containing porous metal powder of an aluminum alloy in a thermoplastic resin containing polyvinyl chloride and a film using the same are excellent in oxygen absorption properties.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

[0005] However, the resin compositions and molded articles disclosed in the above-mentioned Patent Documents 1 to 3 are not intended for use in applications requiring conductivity and weather resistance, and according to the present inventors, these patent documents are not satisfactory in terms of conductivity and weather resistance. Furthermore, polyvinyl chloride resin, which is widely used in this way, generates harmful chlorine compounds and oxides such as dioxins when incinerated, making it a resin with a high environmental burden, and therefore, recycling it in a simple manner is also an issue.

[0006] This invention has been made in view of these circumstances, and its object is to provide conductive thermoplastic resin compositions, molded articles, and methods for producing the same, which have excellent conductivity and weather resistance. It also aims to provide a simple method for recycling polyvinyl chloride resin. [Means for solving the problem]

[0007] The inventors, in order to solve the above problems, conducted intensive research and found that the above problems can be solved by incorporating aluminum fine particles and carbon black in specific amounts into polyvinyl chloride resin. At the same time, they also found that the above problems can be solved by melt-kneading a laminate containing polyvinyl chloride resin as a layer and adding carbon black.

[0008] [1] A conductive thermoplastic resin composition comprising polyvinyl chloride resin (A), aluminum fine particles (B) having an average particle size of 200 to 300 μm, and carbon black (C), wherein the total content of the aluminum fine particles (B) and the carbon black (C) is 43 to 60% by mass with respect to 100% by mass of the conductive thermoplastic resin composition, and the content of the carbon black (C) is 1 / 8 or less of the mass of the aluminum (B). A method for producing a conductive thermoplastic resin composition as described in [2][1], comprising the steps of: (1) cutting and / or crushing a laminate comprising at least a first layer of polyvinyl chloride resin and a second layer of aluminum to obtain fragments of the laminate; (2) adding and mixing polyvinyl chloride resin and carbon black (C) to the fragments to obtain a mixture; and (3) melt-kneading the mixture to form aluminum fine particles (B) from the aluminum in the fragments to obtain a conductive thermoplastic resin composition, wherein the aluminum content in 100% by mass of the laminate is 55 to 85% by mass. A molded article obtained by molding the conductive thermoplastic resin composition described in [3][1]. [4] The molded body according to [3], wherein the molded body is a hot-pressed molded body, a roll sheet molded body, or a calendered molded body. A method for manufacturing a molded article as described in [5][4], comprising the steps of: (1) cutting and / or crushing a laminate comprising at least a first layer of polyvinyl chloride resin and a second layer of aluminum to obtain fragments of the laminate; (2) adding and mixing polyvinyl chloride resin and carbon black (C) to the fragments to obtain a mixture; (3) melt-kneading the mixture to form aluminum fine particles (B) from the aluminum in the fragments to obtain a conductive thermoplastic resin composition; and (4) performing hot press molding, roll sheet molding or calendering, wherein the aluminum content in 100% by mass of the laminate is 55 to 85% by mass. [Effects of the Invention]

[0009] According to the present invention, conductive thermoplastic resin compositions, molded articles, and methods for producing the same, which have excellent conductivity and weather resistance, can be provided. Furthermore, according to the present invention, polyvinyl chloride resin can be recycled in a simple manner. [Modes for carrying out the invention]

[0010] The conductive thermoplastic resin composition, molded articles, and methods for producing them according to the present invention will be described in detail item by item below. <<Conductive thermoplastic resin composition>> One embodiment of the present invention provides a conductive thermoplastic resin composition comprising a polyvinyl chloride resin (A), aluminum fine particles (B) having an average particle size of 200 to 300 μm, and carbon black (C).

[0011] The content of aluminum (B) and carbon black (C) is preferably 43 to 60% by mass, more preferably 43 to 55% by mass, and more preferably 43 to 49% by mass, from the viewpoint of improving the conductivity of the resin composition and its long-term weather resistance.

[0012] <Polyvinyl chloride resin (A)> The polyvinyl chloride resin of the present invention refers to a resin polymerized with vinyl chloride as the main monomer (more than 50 mol%), and may be, for example, a homopolymer of vinyl chloride, a copolymer of vinyl chloride and other monomers, or modified products thereof. Monomers that can copolymerize with vinyl chloride include olefins such as ethylene, propylene, butene, 1-pentene, and butadiene; aromatic vinyl compounds such as styrene and α-methylstyrene; acrylics such as acrylonitrile and methacrylicnitrile; vinylidenes such as vinylidene chloride and vinylidene cyanide; alkyl vinyl ethers such as ethyl vinyl ether, butyl vinyl ether, and isobutyl vinyl ether; unsaturated carboxylic acids and their acid anhydrides such as acrylic acid, methacrylic acid, fumaric acid, maleic acid, and maleic anhydride; and vinyl carboxylates such as vinyl acetate and vinyl propionate. Examples include esters, aryl ethers such as methoxystyrene, dialkyl maleic acids such as dimethyl maleic acid, fumarate esters such as ethyl fumarate, butyl fumarate, and dibutyl fumarate, heterocyclic vinyls such as N-vinylpyrrolidone and vinylpyridine, vinylsilanes such as vinyltrimethoxysilane, vinyltriethoxysilane, vinylmethyldimethoxysilane, and vinyldimethylmethoxysilane, alkyl acrylates such as methyl acrylate and ethyl acrylate, and alkyl methacrylates such as stearyl methacrylate and behenyl methacrylate. Polyvinyl chloride resin (A) may also be a graft copolymer such as ethylene-vinyl acetate-vinyl chloride graft polymer or vinyl chloride-urethane copolymer. Among these, a homopolymer of vinyl chloride or a copolymer of vinyl chloride and vinyl acetate is preferred. Polyvinyl chloride resin (A) may be used alone or in combination of two or more types.

[0013] From the viewpoint of moldability, the average degree of polymerization of the polyvinyl chloride resin (A) is preferably 500 to 4,000, more preferably 600 to 2,000, and even more preferably 700 to 1,200.

[0014] The content of the polyvinyl chloride resin (A) is 24 to 33% by mass, more preferably 27 to 33% by mass, and even more preferably 30 to 33% by mass, based on 100% by mass of the conductive thermoplastic resin composition, from the viewpoint of moldability.

[0015] In the present invention, the polyvinyl chloride resin (A) is not particularly limited, and for example, Kanevinyル (registered trademark) S1001 and Kanevinyル (registered trademark) S1008 manufactured by Kaneka Corporation, TK-800 and TK-1000 manufactured by Shin-Etsu Chemical Co., Ltd., etc. can be used. However, from the viewpoint of recycling, it is desirable to use waste materials containing the polyvinyl chloride resin (A). Details will be described in the manufacturing method described later.

[0016] <Aluminum fine particles (B)> The conductive thermoplastic resin composition contains aluminum fine particles (B) having an average particle diameter of 200 to 300 μm by the sieving method. By including the aluminum fine particles (B) in the composition, a resin composition excellent in conductivity and weather resistance can be obtained. The aluminum fine particles (B) may be used alone or in combination of two or more.

[0017] The average particle diameter of the aluminum fine particles (B) is 200 to 300 μm, preferably 200 to 250 μm or less, from the viewpoints of improving the conductivity of the conductive thermoplastic resin composition and its long-term weather resistance. The lower limit of the average particle diameter of the aluminum fine particles (B) is not particularly limited, but is preferably 100 μm or more.

[0018] In the present invention, the content of the aluminum fine particles (B) is a value obtained by weighing the remaining aluminum fine particles (B) after heating and burning the thermoplastic resin composition. Specifically, the conductive thermoplastic resin composition is placed in a ceramic crucible and heated to a temperature below the melting temperature of the aluminum fine particles (B) and up to a temperature at which other components are completely burned or decomposed, so that the polyvinyl chloride resin (A), carbon black (C), and other components (D) are completely burned or decomposed, and the remaining aluminum fine particles (B) are weighed. The content of the aluminum fine particles (B) is a value obtained by expressing the mass of the remaining aluminum fine particles (B) as a percentage of the mass of the conductive thermoplastic resin composition before combustion or decomposition.

[0019] Also, in the present invention, the average particle diameter of the aluminum fine particles (B) is a value calculated from the mass of each fraction classified by sieving the remaining aluminum fine particles (B). Specifically, using a plurality of stainless steel test sieves (manufactured by Nonaka Rika Kikai Seisakusho Co., Ltd., φ75 mm, mesh openings 2,000 μm, 1,400 μm, 1,000 μm, 600 μm, 425 μm, 300 μm, 180 μm, and 90 μm), the remaining aluminum fine particles (B) are sieved while applying vibration. Next, the mass of the residue on the sieve and the mass obtained in the receiver after passing through all the sieves are weighed. The mesh opening diameter and the passing mass of each sieve are plotted and interpolated, and the mesh opening diameter when the passing mass becomes 50% is taken as the average particle diameter of the aluminum fine particles (B).

[0020] If the average particle diameter of the aluminum fine particles (B) is 200 to 300 μm, the shape of the aluminum fine particles (B) is not particularly limited, and it may be approximately spherical.

[0021] In the present invention, the aluminum fine particles are not particularly limited, and can be #245 from Minalco, aluminum powder from Toyo Aluminum, etc. However, from the viewpoint of recycling, as will be described later, it is preferable to use a laminate containing an aluminum layer as a raw material in the production of the conductive thermoplastic resin composition, and to form aluminum fine particles (B) from the laminate containing the aluminum layer during the manufacturing process.

[0022] <Carbon Black (C)> The conductive thermoplastic resin composition contains carbon black (C). The inclusion of carbon black (C) in the composition improves the conductivity and weather resistance of the resulting conductive thermoplastic resin composition.

[0023] In the present invention, carbon black (C) is not particularly limited, and furnace black, channel black, acetylene black, thermal black, etc. can be used.

[0024] Carbon black (C) may be used alone or in combination of two or more types. Furthermore, carbon black can be granulated using a binder, and a masterbatch in which carbon black is melt-mixed with other resins at a high concentration can also be used. Examples of the above resins include polyvinyl chloride resin, polyolefin resin, polycarbonate resin, polystyrene resin, polyester resin, and acrylic resin, but polyvinyl chloride resin is preferred. The carbon black content in the masterbatch is preferably 1 to 80% by mass, more preferably 10 to 70% by mass, and even more preferably 20 to 60% by mass.

[0025] From the viewpoint of improving the conductivity and weather resistance of the conductive thermoplastic resin composition, the average primary particle diameter of carbon black (C) is preferably 5 to 100 nm, and more preferably 10 to 70 nm. In the present invention, the average primary particle diameter of carbon black (C) is the catalog value.

[0026] From the viewpoint of improving the conductivity and weather resistance of the resin composition, the DBP absorption amount of carbon black (C) is 100-600 cm³. 3 It is preferable that the amount be 100g, and the range is 150-600cm. 3 It is more preferable that the amount is / 100g. In this invention, the DBP absorption amount is a value measured in accordance with JIS K6217-4.

[0027] From the viewpoint of improving the conductivity and weather resistance of the resin composition, the BET specific surface area of ​​carbon black (C) is 50 m². 2 It is preferable that it be 200m or more per gram. 2 It is more preferable that the value is 1 / g or more. In this invention, the BET specific surface area is a value obtained by the nitrogen adsorption method, measured in accordance with JIS K6217-2.

[0028] The carbon black (C) content is preferably 1 / 8 or less, more preferably 1 / 12 or less, and more preferably 1 / 20 or less, relative to the aluminum (B) content, from the viewpoint of improving the conductivity and weather resistance of the resin composition.

[0029] <Other ingredients (D)> The conductive thermoplastic resin composition may contain other components (D) as long as they do not impair the effects of the present invention. Examples of other components (D) include aluminum nanoparticles other than aluminum nanoparticles (B), metal nanoparticles other than aluminum, metals, inorganic nanoparticles other than carbon black, organic nanoparticles, plasticizers, antioxidants, crystal nucleating agents, crystallization accelerators, heat resistant agents, weather resistant agents, flame retardants, flame retardant aids, mold release agents, flow modifiers, and other well-known additives.

[0030] <<Method for producing conductive thermoplastic resin composition>> Next, a method for producing a conductive thermoplastic resin composition will be described. Another embodiment of the present invention is to provide a method for producing a conductive resin composition. The method for producing the conductive thermoplastic resin composition is not particularly limited, and examples include a first embodiment in which polyvinyl chloride resin (A), aluminum fine particles (B), carbon black (C), and other components (D) are melt-kneaded using a known melt-kneading machine such as a single-screw or twin-screw extruder, a Banbury mixer, a kneader, and mixing rolls; and a second embodiment in which polyvinyl chloride resin (A), a laminate including an aluminum layer, carbon black (C), and other components (D) are melt-kneaded using the above-mentioned melt-kneading machine, and aluminum fine particles (B) are formed from the laminate including the aluminum layer during the melt-kneading process to obtain the conductive thermoplastic resin composition. In the second embodiment, it is preferable that the laminate including the aluminum layer is laminated together with a layer of polyvinyl chloride resin. By using such a laminate, it is possible to improve the compatibility between the polyvinyl chloride resin (A) and the aluminum fine particles (B) formed from the aluminum layer, and the conductivity and weather resistance of the resulting conductive thermoplastic resin composition and molded article can be improved.

[0031] In the first and second embodiments, some or all of the plasticizers included as polyvinyl chloride resin (A) and other components (D) may be substituted, and pellets, films, etc., containing these components may be used. Furthermore, in the method for producing the conductive thermoplastic resin composition, some or all of the plasticizers and carbon black (C) included as polyvinyl chloride resin (A) and other components (D) may be substituted, and pellets, films, etc., containing these components may be used. Thus, the components used in the production method of the present invention can be in any combination. It is also preferable to use it in the form of a masterbatch.

[0032] Hereafter, a second embodiment of the present invention, which enables the recycling of polyvinyl chloride resin in a simple manner, will be described with examples.

[0033] <Laminate> The laminate in this section is used as a raw material in the second embodiment. This laminate may be a laminate containing an aluminum layer, a polyvinyl chloride resin, and an optional plasticizer. By using such a laminate, it is possible to improve the compatibility between the polyvinyl chloride resin (A), the optional plasticizer, and the aluminum fine particles (B) formed from the aluminum layer, thereby improving the conductivity and weather resistance of the resulting conductive thermoplastic resin composition.

[0034] The laminate comprising a layer containing polyvinyl chloride resin and an optional plasticizer, and an aluminum layer, is not particularly limited as long as it contains these two layers. Examples include those manufactured by heating a polyvinyl chloride resin film and an aluminum layer at a temperature above the softening point of the polyvinyl chloride resin and then pressing them together, or those manufactured by heating and evaporating aluminum in a vacuum and depositing it onto a polyvinyl chloride film. If necessary, an adhesive layer may be provided between the layer containing polyvinyl chloride resin and an optional plasticizer and the aluminum layer.

[0035] Furthermore, as one embodiment of such a laminate, pharmaceutical packaging (PTP) sheets, pharmaceutical packaging (PTP) sheet waste generated during or after the manufacture of pharmaceutical packaging (PTP) sheets, aluminum laminate sheets for food packaging and their waste materials, aluminum laminate sheets for semiconductor packaging and their waste materials, aluminum vapor-deposited sheets and their waste materials, etc., may be used. In the case of pharmaceutical packaging (PTP) sheets and their waste materials, a layer containing polyvinyl chloride resin and an optional plasticizer corresponding to the pocket portion for storing pharmaceuticals may be included. By using pharmaceutical packaging (PTP) sheets, aluminum laminate sheets for food packaging, aluminum laminate sheets for semiconductor packaging, and aluminum vapor-deposited sheets, environmental protection and recycling can also be achieved.

[0036] The content of aluminum in 100% by mass of the laminate is not particularly limited, but is preferably 50 to 85% by mass, and more preferably 55 to 85% by mass. Furthermore, the content of the layer containing polyvinyl chloride resin and an optional plasticizer in 100% by mass of the laminate is preferably 15 to 50% by mass, and more preferably 15 to 45% by mass.

[0037] The shape of the laminate is not particularly limited, but it is preferably in the form of a sheet. The thickness of the laminate is preferably 10 to 1,000 μm, more preferably 20 to 800 μm, and even more preferably 50 to 500 μm. In drug packaging (PTP) sheets and their waste materials, the apparent thickness is increased because there are voids in the pocket portion that stores the drug, but the thickness of the laminate in this specification does not take into account the thickness of the above-mentioned portion.

[0038] <Step (1) to obtain a fragment of the laminate> The step of obtaining fragments of the laminate in the present invention is a step of obtaining fragmented laminate. When a conductive thermoplastic resin composition is manufactured using the laminate, it is preferable to include a step of cutting and / or crushing the laminate to obtain fragments of the laminate. The fragments obtained in this way are easy to handle, and in addition, aluminum fine particles can be uniformly dispersed in the conductive thermoplastic resin composition. Furthermore, by melt-kneading a mixture obtained by adding and mixing polyvinyl chloride resin (A), carbon black (C), and a plasticizer, aluminum fine particles (B) can be easily formed from the aluminum in the fragments.

[0039] Methods for cutting and / or pulverizing the laminate include using a cutting device such as a shredder, slitter, or cutter, or a pulverizing device such as a mixer or grinder. When pulverizing using a pulverizing device, the stirring speed is preferably 500 to 30,000 rpm, more preferably 1,000 to 25,000 rpm, and even more preferably 3,000 to 20,000 rpm. The stirring time is preferably 1 to 10 minutes, and more preferably 2 to 5 minutes. The stirring temperature is preferably 0 to 80°C, more preferably 0 to 60°C. By stirring within the above temperature range, melting of the polyvinyl chloride resin due to heat generated during stirring can be suppressed.

[0040] The shape and size of the flakes in the laminate are not particularly limited. For example, if the laminate is in the form of a sheet, the shape of the flakes when viewed from the thickness direction may be any shape, such as a triangle, a quadrilateral, or a circle, an ellipse, or an irregular shape. As for the size of the flakes, the average area of ​​the plane when viewed from the thickness direction is 0.3 to 50.0 mm². 2 Preferably, 3.0 to 30.0 mm 2 It is more preferable that the average thickness of the aluminum layer in the flakes is 0.005 to 80 μm. By using flakes having such a shape and size, when the mixture is melt-kneaded, aluminum fine particles (B) with an average particle size of 500 μm or less can be easily formed from the aluminum in the flakes. Thus, the shape and size of the flakes in the laminate can be appropriately adjusted to suit the characteristics of the equipment used in subsequent processes, preferably the equipment used during melt-kneading.

[0041] <Step (2) to obtain the mixture> The step of obtaining the mixture in the present invention is to mix the flaked laminate with carbon black. In step (2) of obtaining the mixture, polyvinyl chloride resin (A) and carbon black (C) are added to and mixed with the laminate fragments. Preferably, the laminate fragments, the added polyvinyl chloride resin (A), and the added carbon black (C) are blended so that the aluminum and carbon black (C) content is 43 to 60% by mass. It is also preferable that the total amount of polyvinyl chloride resin (A) in 100% by mass of the mixture is 30 to 45% by mass. Other components (D) may be added to the mixture. The method for mixing the laminate fragments, polyvinyl chloride resin (A), carbon black (C), and any other components (D) is not particularly limited, and a rotary / revolving mixer, ball mill, roll mill, bead mill, planetary mixer, tumbler, stirrer, agitator, mechanical homogenizer, ultrasonic homogenizer, high-pressure homogenizer, paint shaker, blender, Nauter mixer, Banbury mixer, kneading roll, single-screw extruder, twin-screw extruder, etc., can be used. It is preferable to mix the materials using a single-screw extruder, twin-screw extruder, or the like, which can melt-knead the materials.

[0042] <Step (3) to obtain a conductive thermoplastic resin composition> The step of obtaining the conductive thermoplastic resin composition in the present invention includes forming aluminum fine particles by melt kneading. By melt kneading the mixture, aluminum fine particles (B) with an average particle size of 200 to 300 μm are formed from the aluminum in the flakes. Furthermore, as described above, by using a melt kneader in step (2), steps (2) and (3) can be performed as a series of steps, and the formation of aluminum fine particles can be carried out continuously or simultaneously while mixing. Examples of melt kneading equipment include batch mixers (e.g., Plasticorder manufactured by Brabender), single-screw or twin-screw melt kneading equipment, etc. From the viewpoint of forming aluminum fine particles (B) with an average particle size of 200 to 300 μm from the aluminum in the flakes, the melt kneading conditions are preferably as follows. That is, when using a batch mixer, the screw rotation speed is preferably 2 to 100 rpm, more preferably 5 to 80 rpm, and the kneading time is preferably 1 to 20 minutes, more preferably 2 to 10 minutes. When using a twin-screw melting and kneading apparatus, the screw rotation speed is preferably 20 to 600 rpm, more preferably 50 to 500 rpm, and the extrusion rate during melting and kneading is preferably 10 to 100 kg / hr, more preferably 15 to 80 kg / hr. The kneading temperature is preferably between (softening point of polyvinyl chloride resin) and (softening point of polyvinyl chloride resin + 80°C), and more preferably between (softening point of polyvinyl chloride resin) and (softening point of polyvinyl chloride resin + 60°C). These conditions are also preferable from the viewpoint of recycling polyvinyl chloride resin.

[0043] Furthermore, by referring to the disclosures herein, various molded articles containing polyvinyl chloride resin can be used as raw materials instead of the laminate. As a result, it can be understood that the method for producing the conductive thermoplastic resin composition of the present invention has a wide range of applications and is a technology that can greatly contribute to reducing the environmental impact, which is one of the challenges of polyvinyl chloride resin.

[0044] <<Molded body>> Another embodiment of the present invention is to provide a molded article made using a conductive thermoplastic resin composition. The molded article of the present invention contains the conductive thermoplastic resin composition of the present invention described above. The shape of the molded article can be a film, a sheet, a plate, a pellet, a rod, a powder, a hollow, etc., but a sheet shape is preferred.

[0045] <<Manufacturing Method for Molded Products>> Another embodiment of the present invention provides a method for manufacturing a molded article using a conductive thermoplastic resin composition. In this invention, steps (1) to (3) are the same as those for the method of producing the thermoplastic resin composition and are therefore omitted, and only step (4) will be described. Step (4) is not particularly limited as long as the desired molded article can be obtained, and known molding methods can be used. Examples include hot press molding, roll sheet molding, calendering, injection molding, extrusion molding, blow molding, and hollow molding, and it is particularly preferable to mold by hot press molding.

[0046] The molding conditions can be appropriately selected depending on the intended use, molding method, molding machine, etc. For example, the molding conditions in a hot press molding method are preferably as follows: The molding temperature is preferably 140 to 180°C, and more preferably 150 to 170°C. The pressurizing time is preferably 1 to 60 minutes, and more preferably 1 to 20 minutes. Furthermore, the press pressure is preferably 1 to 20 MPa, and more preferably 1 to 10 MPa. [Examples]

[0047] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples.

[0048] <Evaluation Method> (1) Content of aluminum fine particles (B) in the conductive thermoplastic resin composition The content of aluminum fine particles (B) in the conductive thermoplastic resin composition was determined by placing 2 g of the conductive thermoplastic resin composition in a ceramic crucible, burning or decomposing it at 600°C, and weighing the remaining aluminum fine particles (B). The content (mass%) of aluminum fine particles (B) was calculated as the mass of the remaining aluminum fine particles (B) relative to the mass of the conductive thermoplastic resin composition before burning or decomposition.

[0049] (2) Average particle size of aluminum fine particles (B) Using multiple stainless steel test sieves (manufactured by Nonaka Rikaki Seisakusho Co., Ltd., φ75 mm, with mesh sizes of 2,000 μm, 1,400 μm, 1,000 μm, 600 μm, 425 μm, 300 μm, 180 μm, and 90 μm), the remaining aluminum fine particles (B) obtained in (1) above were sieved while vibrating. Next, the mass of the residue on the sieves and the mass obtained in the receiver after passing through all the sieves were weighed. The mesh diameter and the mass passing through each sieve were plotted and interpolated to determine the average particle size of the aluminum fine particles (B) when the passing mass was 50%.

[0050] (3) Fabrication of molded products Using the conductive thermoplastic resin compositions of the examples and comparative examples, molded bodies were obtained by applying pressure at 5 MPa for 5 minutes in a press machine set to 170°C, using a mold with sides of 10 cm on each side and a thickness of 2 mm.

[0051] (4) Measurement of volume resistivity and evaluation of uniformity of molded articles The molded body obtained in (3) was placed on a metal plate electrode, and a φ5 cm metal electrode was placed on top of the molded body. An insulation resistance meter (manufactured by Kyoritsu Electrical Instruments Co., Ltd.) was used to measure the resistance value by applying a voltage of 500 V between the two electrodes, and the volume resistivity was determined from the contact area between the molded body and the electrode and the thickness of the molded body. For each condition, the volume resistivity was measured at four locations, dividing the molded body into four equal parts of a 5cm square. The average of the four volume resistivity measurements in the thickness direction was taken as the volume resistivity of the molded body. The acceptable standard for volume resistivity was set at 10,000 Ω·cm or less. In addition, the percentage of the four measurements that met the acceptable standard was taken as the uniformity value. The acceptable standard for uniformity was set at 100%.

[0052] (5) Weather resistance evaluation The molded articles evaluated in (4) were stored for 15 days in an environmental testing chamber (manufactured by ESPEC Corporation) at a temperature of 85°C and a humidity of 85%RH. After 15 days, the volume resistivity of the molded articles was measured and their uniformity was evaluated using the same method as in (4) above.

[0053] <Raw materials used> The following raw materials were used in the examples and comparative examples. • Laminate containing a layer of polyvinyl chloride resin and a layer of aluminum: ORIX Environmental Corporation (aluminum content: 70% by mass, polyvinyl chloride resin (A) content: 30% by mass) • Polyvinyl chloride resin (A): Manufactured by Kaneka Corporation, KaneVinyl (registered trademark) S100 1 • Plasticizer: Diisononyl phthalate, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. • Carbon black masterbatch: Manufactured by Dainichi Seika Kogyo Co., Ltd., Neocon (registered trademark) (Carbon black (C) content: 20% by mass, polyvinyl chloride resin (A): 44% by mass, diisononyl phthalate: 36% by mass)

[0054] <Fracture of laminated structures> A laminate containing a polyvinyl chloride resin layer and an aluminum layer was continuously fed into a crusher (manufactured by Horai Co., Ltd.) at a speed of 20 kg / h, and crushed while controlling the internal temperature of the machine to less than 60°C to obtain fine pieces of the laminate.

[0055] Example 1 The fragments obtained by crushing the laminate, carbon black masterbatch, polyvinyl chloride resin (A), and diisononyl phthalate were mixed in a mass ratio of 57.1 / 15.0 / 14.7 / 13.2. The resulting mixture was fed into a 3-inch roll set to a roll temperature of 160°C and kneaded for 10 minutes to obtain a conductive thermoplastic resin composition. The content and average particle size of aluminum fine particles (B) in the conductive thermoplastic resin composition were 40% by mass and 250 μm, respectively. Table 1 shows the composition of the conductive thermoplastic resin composition of Example 1.

[0056] Example 2 The thermoplastic resin composition of Example 2 was obtained in the same manner as in Example 1, except that the mass ratio of the flakes obtained by crushing the laminate, carbon black masterbatch, polyvinyl chloride resin (A), and diisononyl phthalate was changed to 61.4 / 5.0 / 17.6 / 16.0. The content and average particle size of aluminum fine particles (B) in the conductive thermoplastic resin composition were 43% by mass and 250 μm, respectively. Table 1 shows the composition of the conductive thermoplastic resin composition for Example 2.

[0057] Example 3 The thermoplastic resin composition of Example 3 was obtained in the same manner as in Example 1, except that the mass ratio of the flakes obtained by crushing the laminate, carbon black masterbatch, polyvinyl chloride resin (A), and diisononyl phthalate was changed to 64.3 / 5.0 / 15.8 / 14.9. The content and average particle size of aluminum fine particles (B) in the conductive thermoplastic resin composition were 45% by mass and 250 μm, respectively. Table 1 shows the composition of the conductive thermoplastic resin composition of Example 3.

[0058] Example 4 The conductive thermoplastic resin composition of Example 4 was obtained in the same manner as in Example 1, except that the mass ratio of the flakes obtained by crushing the laminate, carbon black masterbatch, polyvinyl chloride resin (A), and diisononyl phthalate was changed to 68.6 / 5.0 / 13.2 / 13.3. The content and average particle size of aluminum fine particles (B) in the conductive thermoplastic resin composition were 48% by mass and 250 μm, respectively. Table 1 shows the composition of the conductive thermoplastic resin composition of Example 4.

[0059] Comparative Example 1 A conductive thermoplastic resin composition of Comparative Example 1 was obtained in the same manner as in Example 1, except that the mass ratio of the flakes obtained by crushing the laminate, polyvinyl chloride resin (A), and diisononyl phthalate was changed to 50.0 / 27.1 / 22.9. The content and average particle size of aluminum fine particles (B) in the conductive thermoplastic resin composition were 35% by mass and 250 μm, respectively. Table 1 shows the composition of the conductive thermoplastic resin composition of Comparative Example 1.

[0060] Comparative Example 2 A conductive thermoplastic resin composition for Comparative Example 2 was obtained in the same manner as in Example 1, except that the mass ratio of the flakes obtained by crushing the laminate, polyvinyl chloride resin (A), and diisononyl phthalate was changed to 57.1 / 21.7 / 21.2. The content and average particle size of aluminum fine particles (B) in the conductive thermoplastic resin composition were 40% by mass and 250 μm, respectively. Table 1 shows the composition of the conductive thermoplastic resin composition of Comparative Example 2.

[0061] Comparative Example 3 A thermoplastic resin composition for Comparative Example 3 was obtained in the same manner as in Example 1, except that the mass ratio of the flakes obtained by crushing the laminate, carbon black masterbatch, polyvinyl chloride resin (A), and diisononyl phthalate was changed to 57.1 / 5.0 / 20.2 / 17.6. The content and average particle size of aluminum fine particles (B) in the conductive thermoplastic resin composition were 40% by mass and 250 μm, respectively. Table 1 shows the composition of the conductive thermoplastic resin composition of Comparative Example 3.

[0062] Using the conductive thermoplastic resin compositions of Examples 1-4 and Comparative Examples 1-3, molded articles were prepared by the method described above, and the volume resistivity of the molded articles was measured. Furthermore, the volume resistivity was measured over time under high temperature and high humidity conditions. The measurement results are shown in Table 1.

[0063] [Table 1]

[0064] Table 1 shows that the conductive thermoplastic resin compositions of Examples 1 to 4 exhibited low initial and 15-day volume resistivity in the molded articles, as well as excellent initial conductivity and weather resistance under high temperature and high humidity conditions. Comparative Example 1, in which the total amount of aluminum nanoparticles and carbon black in 100% by mass of the conductive thermoplastic resin composition was 35% by mass, did not exhibit conductivity. Comparative Example 2, in which the total amount of aluminum nanoparticles and carbon black in 100% by mass of the conductive thermoplastic resin composition was 40% by mass, showed inferior volume resistivity and poor weather resistance of volume resistivity. Comparative Example 3, in which the total amount of aluminum nanoparticles and carbon black in 100% by mass of the conductive thermoplastic resin composition was 41% by mass, showed little change in volume resistivity after 15 days, but had inferior initial volume resistivity. [Industrial applicability]

[0065] The conductive thermoplastic resin composition and molded articles of the present invention are suitably used in various applications where conductivity and weather resistance are required. Furthermore, the method for producing the conductive thermoplastic resin composition and the method for producing the molded article of the present invention can be suitably applied to the recycling of polyvinyl chloride resin.

Claims

1. A conductive thermoplastic resin composition comprising polyvinyl chloride resin (A), aluminum fine particles (B) having an average particle size of 200 to 300 μm, and carbon black (C), wherein the total content of the aluminum fine particles (B) and the carbon black (C) is 43 to 60% by mass with respect to 100% by mass of the conductive thermoplastic resin composition, and the content of the carbon black (C) is 1 / 8 or less of the mass of the aluminum (B).

2. A method for producing a conductive thermoplastic resin composition according to claim 1, comprising the steps of: (1) cutting and / or pulverizing a laminate comprising at least a first layer of polyvinyl chloride resin and a second layer of aluminum to obtain fragments of the laminate; (2) adding and mixing polyvinyl chloride resin and carbon black (C) to the fragments to obtain a mixture; and (3) melt-kneading the mixture to form aluminum fine particles (B) from the aluminum in the fragments to obtain a conductive thermoplastic resin composition, wherein the aluminum content in 100% by mass of the laminate is 55 to 85% by mass.

3. A molded article obtained by molding the conductive thermoplastic resin composition described in claim 1.

4. The molded body according to claim 3, wherein the molded body is a hot-pressed molded body, a roll sheet molded body, or a calendered molded body.

5. A method for manufacturing a molded article according to claim 4, comprising the steps of: (1) cutting and / or crushing a laminate comprising at least a first layer of polyvinyl chloride resin and a second layer of aluminum to obtain fragments of the laminate; (2) adding and mixing polyvinyl chloride resin and carbon black (C) to the fragments to obtain a mixture; (3) melt-kneading the mixture to form aluminum fine particles (B) from the aluminum in the fragments to obtain a conductive thermoplastic resin composition; and (4) performing hot press molding, roll sheet molding or calendering, wherein the aluminum content in 100% by mass of the laminate is 55 to 85% by mass.

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