Method for manufacturing conductive composite material

Abstract

The objective of the present invention is to provide a method for manufacturing a conductive composite material containing a conductive filler and a thermoplastic elastomer using a mixing apparatus capable of continuously producing a mixed material of a certain quality. As a means to solve the problem, in an extruder (3) that continuously discharges a mixture produced by mixing raw materials by a screw (21), the screw (21) has a screw body (37), and raw materials conveyed along the outer surface of the screw body (37) are introduced into a passage (88) from an inlet (91) by increasing the pressure in the conveying section (81) by a barrier section (82), and while continuously discharging the mixture, in the extruder (3), the raw materials conveyed along the outer surface of the screw body (37) are guided to the conveying section (81) through an outlet provided in the screw body (37), and the raw materials contain a conductive filler and a thermoplastic elastomer.

Description

Technology Field

[0001] The present invention relates to a method for manufacturing a conductive composite material using a conductive filler and a thermoplastic elastomer as raw materials, by using a mixing device equipped with an extruder that mixes the raw materials while imparting shear and elongation effects. Background Technology

[0002] Recently, various conductive fillers, such as metal-based, metal oxide-based, and carbon-based materials, are being used to impart conductivity to resins. Among carbon-based conductive fillers, carbon nanotubes (hereinafter appropriately referred to as "CNT") are attracting attention because they possess unique properties. For example, Patent Document 1 describes a conductive composition comprising expanded graphite, CNTs, and a polymer compound. The said document describes a method for manufacturing a conductive composition in which carbon nanotubes are dispersed in a solvent in which a polymer compound is dissolved, mixed with expanded graphite, and then the solvent is removed; however, this manufacturing method has low productivity.

[0003] Patent Document 2 describes a melt-kneading method for uniformly dispersing CNTs at the nano level in a thermoplastic resin by creating a high-shear flow state. Although the method described in the said document has higher productivity than the manufacturing method of Patent Document 1, it is not suitable for the continuous production of resin compositions.

[0004] Patent document 3 describes a mixing apparatus and a mixing method that enable the continuous production of a mixed material of a certain quality by continuously conveying the material to be processed in a mixing process using a molten material as a raw material. Prior art literature

[0005] Japanese Patent Publication No. 2017-133042, Japanese Patent Publication No. 2008-266577, Japanese Patent Publication No. 2015-227052 The problem to be solved

[0006] According to the mixing apparatus and mixing method described in Patent Document 3, a resin composition can be produced continuously. However, what is described in the said document is a transparent mixture obtained by mixing a molten material consisting of two types of resin materials, polycarbonate resin (PC) and polymethacrylic acid resin (PMMA), and a method for manufacturing a conductive composite material by mixing a conductive filler and a thermoplastic elastomer is not described.

[0007] The objective of the present invention is to provide a method for manufacturing a conductive composite material containing a conductive filler and a thermoplastic elastomer using a mixing apparatus capable of continuously producing a mixed material of a certain quality. means of solving the problem

[0008] The present invention relates to a method for manufacturing a conductive composite material, wherein the extruder continuously discharges a mixture produced by mixing raw materials by means of a screw, the screw has a screw body that rotates around a straight axis along the direction of conveying the raw materials, and a passage is provided inside the screw body through which the raw materials introduced from an inlet opened on the outer surface of the screw body flow, and the raw materials conveyed along the outer surface of the screw body have their pressure increased by restricting their conveying in a conveying section provided in the screw body by a barrier part that restricts the conveying of the raw materials, and the raw materials in the conveying section with increased pressure are introduced from the inlet into the passage while the mixture is continuously discharged, wherein the raw materials conveyed along the outer surface of the screw body in the extruder, after flowing through the passage, are guided to the conveying section through an outlet provided on the outer surface of the screw body, wherein the raw materials are a conductive filler and a thermoplastic This is a method for manufacturing a conductive composite material containing an elastomer. Effects of the invention

[0009] According to the present invention, in a mixing process in which raw materials are mixed by means of a screw, the material to be processed is continuously conveyed without stagnation, thereby enabling the continuous production of a highly conductive composite material containing a conductive filler and a thermoplastic elastomer. Brief explanation of the drawing

[0010] FIG. 1 is a perspective view schematically showing a continuous high-shear processing device (mixing device) according to a first embodiment. FIG. 2 is a cross-sectional view of the first extruder used in the first embodiment. FIG. 3 is a perspective view showing the state in which two screws of a first extruder are engaged with each other in a first embodiment. FIG. 4 is a cross-sectional view of the third extruder used in the first embodiment. FIG. 5 is a cross-sectional view of the second extruder used in the first embodiment. FIG. 6 is a cross-sectional view of a second extruder in which both the barrel and the screw are shown in cross-section in the first embodiment. FIG. 7 is a side view of the screw used in the first embodiment. FIG. 8 is a cross-sectional view along the line F8-F8 of FIG. 6. FIG. 9 is a cross-sectional view along the line F9-F9 of FIG. 6. FIG. 10 is a side view showing the flow direction of the raw material with respect to the screw in the first embodiment. FIG. 11 is a cross-sectional view of a second extruder schematically showing the flow direction of the raw material when the screw rotates in the first embodiment. FIG. 12 is a cross-sectional view of a second extruder used in a second embodiment. FIG. 13 is a cross-sectional view of the second extruder used in the third embodiment. FIG. 14 is a cross-sectional view of a second extruder in which both the barrel and the screw are shown in cross-section in the third embodiment. FIG. 15 is a cross-sectional view along the line F15-F15 of FIG. 14. FIG. 16 is a perspective view of a tube used in the third embodiment. FIG. 17 is a side view showing the flow direction of the raw material with respect to the screw in the third embodiment. FIG. 18 is a cross-sectional view of a second extruder schematically showing the flow direction of the raw material when the screw is rotated in the third embodiment. FIG. 19 is a cross-sectional view of the second extruder used in the fourth embodiment. FIG. 20 is a cross-sectional view of a second extruder in which both the barrel and the screw are shown in cross-section in the fourth embodiment. FIG. 21 is a side view of the screw used in the fourth embodiment. FIG. 22 is a cross-sectional view along the line F22-F22 of FIG. 20. FIG. 23 is a perspective view of the body used in the fourth embodiment. FIG. 24 is a cross-sectional view of the body shown in FIG. 23. FIG. 25 is a perspective view showing another configuration example of a body used in the fourth embodiment. FIG. 26 is a side view showing the flow direction of the raw material with respect to the screw in the fourth embodiment. FIG. 27 is a cross-sectional view of a second extruder schematically showing the flow direction of the raw material when the screw is rotated in the fourth embodiment. FIG. 28 is a cross-sectional view of a first extruder according to a fifth embodiment. Figure 29 is a graph showing the effect of the number of rotations of the screw and the number of times the passage passes on the conductivity of the conductive composite material. Figure 30 is a graph showing the relationship between the number of times a passage passes and the conductivity of a conductive composite material. Figure 31 is a graph showing the relationship between the amount of CNT added and the conductivity of the conductive composite material. FIG. 32 is a graph showing the relationship between the number of times a passage passes and the tensile strength of a conductive composite material. FIG. 33 is a graph showing the effect of differences in the configuration of the passages in a continuous mixing device on the conductivity of a conductive composite material. FIG. 34 is a graph showing the effect of the diameter of the circle of the passage cross-section in a continuous mixing device on the conductivity of a conductive composite material. Figure 35 is a graph showing the effect of differences in mixing devices on the conductivity of conductive composite materials. Specific details for implementing the invention

[0011] An embodiment of the present invention will be described with reference to the mixing apparatus used in the manufacturing method of the present invention.

[0012] [First embodiment]

[0013] Hereinafter, a first embodiment will be described with reference to FIGS. 1 to 11.

[0014] FIG. 1 schematically shows the configuration of a continuous high-shear processing device (mixing device) (1) according to a first embodiment. The high-shear processing device (1) is equipped with a first extruder (processor) (2), a second extruder (3), and a third extruder (deaeration device) (4). The first extruder (2), the second extruder (3), and the third extruder (4) are connected in series with each other.

[0015] The first extruder (2) is a processor for pre-mixing and melting, for example, two types of incompatible materials. Here, conductive filler and thermoplastic elastomer are used as the two types of materials. These materials are supplied to the first extruder (2) in a state such as pellets or powder.

[0016] Examples of conductive fillers used in the present invention include carbon-based conductive fillers such as carbon black, graphite, and CNT. Additionally, examples of thermoplastic elastomers (TPEs) include styrene-based TPEs such as styrene-butadiene-based (SBS) and hydrogenated styrene-butadiene-based (SEBS, SBBS), and urethane-based TPEs.

[0017] In this embodiment, to enhance the degree of mixing and melting of the conductive filler (hereinafter appropriately referred to as "filler") and the thermoplastic elastomer (hereinafter appropriately referred to as "resin"), a co-rotating twin-screw mixer is used as the first extruder (2). FIGS. 2 and FIGS. 3 disclose an example of a twin-screw mixer. The twin-screw mixer is equipped with a barrel (6) and two screws (7a, 7b) housed inside the barrel (6). The barrel (6) includes a cylinder section (8) having a shape formed by combining two cylinders. The resin is continuously supplied to the cylinder section (8) from a supply port (9) provided at one end of the barrel (6). Additionally, the barrel (6) contains a heater for melting the resin.

[0018] The screws (7a, 7b) are received in the cylinder section (8) while interlocked with each other. The screws (7a, 7b) receive torque transmitted from a motor not shown and rotate in the same direction as each other. As shown in FIG. 3, the screws (7a, 7b) each have a feed section (11), a mixing section (12), and a pumping section (13). The feed section (11), the mixing section (12), and the pumping section (13) are arranged in a line along the axial direction of the screws (7a, 7b).

[0019] The feed section (11) has a flight (4) that is twisted in a spiral shape. The flight (4) of the screw (7a, 7b) rotates while interlocking with each other and conveys the material containing the filler and resin supplied from the supply port (9) toward the mixing section (12).

[0020] The mixing section (12) has a plurality of discs (15) arranged in the axial direction of the screws (7a, 7b). The discs (15) of the screws (7a, 7b) rotate facing each other and preliminarily mix the material containing the filler and resin sent from the feed section (11). The mixed material is sent to the pumping section (13) by the rotation of the screws (7a, 7b).

[0021] The pumping section (13) has a flight (16) that is twisted in a spiral shape. The flight (16) of the screw (7a, 7b) rotates while interlocking with each other and extrudes the pre-mixed material from the discharge end of the barrel (6).

[0022] According to this twin-screw mixer, the resin in the material supplied to the feed section (11) of the screws (7a, 7b) is melted by receiving heat from the heater and shear heat generated by the rotation of the screws (7a, 7b). The resin and filler melted by preliminary mixing in the twin-screw mixer constitute the blended raw material. The raw material is continuously supplied to the second extruder (3) from the discharge end of the barrel (6), as indicated by arrow A in FIG. 1.

[0023] In addition, by configuring the first extruder (2) as a twin-screw mixer, not only can the resin be melted, but a shear action can also be imparted to the resin and filler. Therefore, at the point when the raw material is supplied to the second extruder (3), the raw material is melted by preliminary mixing in the first extruder (2) and maintained at an optimal viscosity. Furthermore, by configuring the first extruder (2) as a twin-screw mixer, a predetermined amount of raw material can be stably supplied per unit time when the raw material is continuously supplied to the second extruder (3). Thus, the burden on the second extruder (3), which is in full-scale mixing of the raw material, can be reduced.

[0024] The second extruder (3) is a component for producing a mixture in which the filler component is highly dispersed within the resin component of the raw material. In this embodiment, a single-screw extruder is used as the second extruder (3). The single-screw extruder is equipped with a barrel (20) and a single screw (21). The screw (21) has the function of repeatedly applying shearing and elongating actions to the molten raw material. The configuration of the second extruder (3) including the screw (21) will be explained in detail later.

[0025] The third extruder (4) is a component for sucking in and removing gas components contained in the mixture discharged from the second extruder (3). In this embodiment, a single-axis extruder is used as the third extruder (4). As shown in FIG. 4, the single-axis extruder is equipped with a barrel (22) and a single vent screw (23) housed in the barrel (22). The barrel (22) includes a straight cylindrical cylinder section (24). The mixture extruded from the second extruder (3) is continuously supplied to the cylinder section (24) from one end along the axial direction of the cylinder section (24).

[0026] The barrel (22) has a vent port (25). The vent port (25) is connected to a vacuum pump (26) and is opened in the middle section along the axial direction of the cylinder section (24). Additionally, the other end of the cylinder section (24) of the barrel (22) is closed by a head section (27). The head section (27) has a discharge port (28) for discharging the mixture.

[0027] The vent screw (23) is housed in the cylinder section (24). The vent screw (23) receives torque transmitted from a motor not shown and rotates in one direction. The vent screw (23) has a flight (29) that is twisted in a spiral shape. The flight (29) rotates integrally with the vent screw (23) and continuously conveys the mixture supplied to the cylinder section (24) toward the head section (27). When the mixture is conveyed to a position corresponding to the vent opening (25), it receives vacuum pressure from the vacuum pump (26). That is, by removing the inside of the cylinder section (24) under negative pressure by the vacuum pump, gaseous substances or other volatile components contained in the mixture are continuously sucked out and removed from the mixture. The mixture from which gaseous substances or other volatile components have been removed is continuously discharged as a conductive composite material from the discharge port (28) of the head part (27) out of the high-shear processing device (1).

[0028] Next, the second extruder (3) will be described in detail.

[0029] As shown in FIGS. 5 and 6, the barrel (20) of the second extruder (3) is arranged horizontally in a straight barrel shape. The barrel (20) is divided into a plurality of barrel elements (31).

[0030] Each barrel element (31) has a cylindrical through hole (32). The barrel elements (31) are integrally joined by bolt fastening so that each through hole (32) is continuous in a coaxial shape. The through holes (32) of the barrel elements (31) cooperate with each other to define a cylindrical cylinder portion (33) inside the barrel (20). The cylinder portion (33) extends in the axial direction of the barrel (20).

[0031] A supply port (34) is formed at one end along the axial direction of the barrel (20). The supply port (34) is connected to the cylinder part (33), and raw materials blended in the first extruder (2) are continuously supplied to the supply port (34).

[0032] The barrel (20) is equipped with a heater that is not shown. The heater adjusts the temperature of the barrel (20) so that the temperature of the barrel (20) becomes an optimal value for mixing raw materials. Additionally, the barrel (20) is equipped with a refrigerant passage (35) through which a refrigerant, such as water or oil, flows. The refrigerant passage (35) is arranged to surround the cylinder portion (33). When the temperature of the barrel (20) exceeds a predetermined upper limit, the refrigerant flows along the refrigerant passage (35) and forcibly cools the barrel (20).

[0033] The other end along the axial direction of the barrel (20) is closed by the head portion (36). The head portion (36) has a discharge port (36a). The discharge port (36a) is connected to the third extruder (4) and is located on the opposite side along the axial direction of the barrel (20) with respect to the supply port (34).

[0034] As shown in FIGS. 5 to 7, the screw (21) is provided with a screw body (37). The screw body (37) of the present embodiment is composed of one rotation axis (38) and a plurality of cylindrical bodies (39).

[0035] The rotational shaft (38) is provided with a first shaft portion (40) and a second shaft portion (41). The first shaft portion (40) is located at the base of the rotational shaft (38), which is on the side of one end of the barrel (20). The first shaft portion (40) includes a connecting portion (42) and a stopper portion (43). The connecting portion (42) is connected to a driving source, such as a motor, via a coupling not shown. The stopper portion (43) is provided in a coaxial shape with the connecting portion (42). The stopper portion (43) has a larger diameter than the connecting portion (42).

[0036] The second shaft portion (41) extends coaxially from the end surface of the stopper portion (43) of the first shaft portion (40). The second shaft portion (41) has a length that spans approximately the entire length of the barrel (20) and has a tip facing the head portion (36). A straight axis line (O1) that penetrates the first shaft portion (40) and the second shaft portion (41) coaxially extends horizontally in the axial direction of the rotation axis (38).

[0037] The second shaft portion (41) is a solid cylindrical shape with a diameter smaller than that of the stopper portion (43). As shown in FIGS. 8 and 9, a pair of keys (45a, 45b) are mounted on the outer surface of the second shaft portion (41). The keys (45a, 45b) extend in the axial direction of the second shaft portion (41) at a position offset by 180° in the circumferential direction of the second shaft portion (41).

[0038] As shown in FIGS. 6 to 9, each tube (39) is configured so that a second shaft portion (41) penetrates it in a coaxial shape. A pair of key grooves (49a, 49b) are formed on the inner circumferential surface of the tube (39). The key grooves (49a, 49b) extend in the axial direction of the tube (39) at a position offset by 180° in the circumferential direction of the tube (39).

[0039] The tube (39) is inserted onto the second shaft (41) from the front end direction of the second shaft (41) while the key grooves (49a, 49b) are aligned with the keys (45a, 45b) of the second shaft (41). In this embodiment, a first collar (44) is interposed between the tube (39) initially inserted onto the second shaft (41) and the end surface of the stopper part (43) of the first shaft (40). Additionally, after all the tubes (39) are inserted onto the second shaft (41), a fixing screw (52) is screw-fastened through the front end surface of the second shaft (41) with the second collar (51) interposed therebetween.

[0040] By this screw fastening, all tubes (39) are fastened in the axial direction of the second shaft (41) between the first collar (44) and the second collar (51), and the end surfaces of adjacent tubes (39) are in close contact without any gap.

[0041] At this time, all the tubes (39) are joined in a coaxial shape on the second shaft (41), so that each tube (39) and the rotation shaft (38) are integrally assembled. Accordingly, it becomes possible to rotate each tube (39) together with the rotation shaft (38) around the axis (O1), that is, to rotate the screw body (37) around the axis (O1).

[0042] In this state, each body (39) becomes a component that defines the outer diameter (D1) (see FIG. 8) of the screw body (37). That is, each body (39) joined in a coaxial shape along the second shaft (41) has its outer diameter (D1) set to be the same as that of each other. The outer diameter (D1) of the screw body (37) (each body (39)) is a diameter defined by passing through the axis line (O1), which is the center of rotation of the rotation axis (38).

[0043] Accordingly, a segment-type screw (21) is configured such that the outer diameter (D1) of the screw body (37) (each body (39)) is a constant value. The segment-type screw (21) can maintain a plurality of screw elements in a free sequence and combination along the rotation axis (38) (i.e., the second axis portion (41)). As for the screw elements, for example, a body (39) in which at least a part of the flights (56, 57, 58) described later is formed can be defined as one screw element.

[0044] In this way, by segmenting the screw (21), the convenience of changing or adjusting the specifications of the screw (21), or performing maintenance, can be significantly improved.

[0045] In addition, in this embodiment, the cylindrical body (39) is not limited to being fixed to the rotation axis (38) by keys (45a, 45b). For example, instead of keys (45a, 45b), the body (39) may be fixed to the rotation axis (38) using the spline shown in FIG. 2.

[0046] Additionally, the segment screw (21) is received in a coaxial shape in the cylinder portion (33) of the barrel (20). Specifically, a screw body (37) in which a plurality of screw elements are maintained along a rotation axis (38) (second axis portion (41)) is rotatably received in the cylinder portion (33). In this state, the first axis portion (40) (joint portion (42), stopper portion (43)) of the rotation axis (38) protrudes out of the barrel (20) from one end of the barrel (20).

[0047] In addition, in this state, a conveying path (53) for conveying raw materials is formed between the outer surface along the circumferential direction of the screw body (37) and the inner surface of the cylinder part (33). The conveying path (53) has a cross-sectional shape along the diameter direction of the cylinder part (33) that is circular and extends axially along the cylinder part (33).

[0048] In this embodiment, when the screw (21) receives torque from a driving source, it rotates left in a counterclockwise direction when viewed from the side of the base of the screw (21), as indicated by the arrow in FIG. 5. The rotational speed of the screw (21) suitable for manufacturing a highly conductive composite material varies depending on the outer diameter of the screw (21). Generally, as the outer diameter of the screw (21) decreases, the suitable rotational speed tends to increase. When using a screw (21) with an outer diameter of 30 mm or more and 50 mm or less, the rotational speed of the screw (21) is preferably 100 rpm to 1000 rpm, more preferably 200 rpm to 600 rpm, and even more preferably 300 rpm to 500 rpm.

[0049] As shown in FIGS. 5 to 7, the screw body (37) has a plurality of conveying sections (54, 59) for conveying raw materials and a plurality of barrier sections (55) for restricting the flow of raw materials. That is, a barrier section (55) is disposed at the base of the screw body (37) corresponding to one end of the barrel (20), and a discharge conveying section (59) is disposed at the front end of the screw body (37) corresponding to the other end of the barrel (20). In addition, between the barrier section (55) and the conveying section (59), the conveying section (54) and the barrier section (55) are alternately arranged in the axial direction from the base of the screw body (37) toward the front end.

[0050] Additionally, the supply port (34) of the barrel (20) is open toward the return section (54) positioned on the side of the base of the screw body (37).

[0051] Each conveying section (54) has a flight (56) that is twisted in a spiral shape. The flight (56) protrudes toward the conveying path (53) from the outer surface along the circumferential direction of the body (39). The flight (56) is twisted so that when the screw (21) turns left, the raw material is conveyed from the tip of the screw body (37) toward the base. That is, the flight (56) is twisted to the left, like a left-hand screw.

[0052] Additionally, the discharge conveying unit (59) has a flight (58) that is twisted in a spiral shape. The flight (58) protrudes toward the conveying path (53) from the outer surface along the circumferential direction of the body (39). The flight (58) is twisted so that when the screw (21) turns left, the raw material is conveyed from the base of the screw body (37) toward the tip. That is, the flight (58) is twisted to the right, like a right-hand screw.

[0053] Each barrier section (55) has a flight (57) that is twisted in a spiral shape. The flight (57) protrudes toward the conveying path (53) from the outer surface along the circumferential direction of the body (39). The flight (57) is twisted so that when the screw (21) turns left, the raw material is conveyed from the base of the screw body (37) toward the tip. That is, the flight (57) is twisted to the right, like a right-hand screw.

[0054] The twist pitch of the flight (57) of each barrier section (55) is set to be equal to or smaller than the twist pitch of the flight (56, 58) of the return section (54, 59). Additionally, a small clearance is secured between the top section of the flight (56, 57, 58) and the inner surface of the cylinder section (33) of the barrel (20).

[0055] In this case, it is preferable to set the clearance between the outer diameter portion of the barrier portion (55) (top portion of the flight (57)) and the inner circumferential surface of the cylinder portion (33) to a range of 0.1 mm or more and 2 mm or less. More preferably, the clearance is set to a range of 0.1 mm or more and 0.7 mm or less. Accordingly, the raw material passing through the clearance can be reliably restricted.

[0056] In addition, the axial direction of the screw body (37) can be said to be the long side direction of the screw body (37), or in other words, the long side direction of the screw (21).

[0057] Here, the length of the conveying section (54, 59) along the axial direction of the screw body (37) is appropriately set according to, for example, the type of raw material, the degree of mixing of the raw material, the production volume of the mixed material per unit time, etc. The conveying section (54, 59) refers to an area where flights (56, 58) are formed on at least the outer surface of the body (39), but it is not specified as an area between the starting point and the ending point of the flights (56, 58).

[0058] That is, an area of ​​the outer surface of the body (39) that is separated from the flight (56, 58) may also be considered as a return section (54, 59). For example, if a cylindrical spacer or a cylindrical collar is placed at a position adjacent to the body (39) having the flight (56, 58), said spacer or collar may also be included in the return section (54, 59).

[0059] Additionally, the length of the barrier section (55) along the axial direction of the screw body (37) is appropriately set according to, for example, the type of raw material, the degree of mixing of the raw material, the production volume of the mixed material per unit time, etc. The barrier section (55) functions to block the flow of the raw material sent by the conveying section (54). That is, the barrier section (55) is configured to be adjacent to the conveying section (54) on the downstream side of the raw material's conveying direction, and to prevent the raw material sent by the conveying section (54) from passing through the clearance between the top part of the flight (57) and the inner surface of the cylinder section (33).

[0060] In addition, in the screw (21) described above, each flight (56, 57, 58) protrudes toward the return path (53) from the outer surface of a plurality of tubes (39) having the same outer diameter (D1). Because of this, the outer surface along the circumferential direction of each tube (39) defines the curve of the screw (21). The curve of the screw (21) is maintained at a constant value over the entire length of the screw (21).

[0061] As shown in FIGS. 5 to 7 and FIG. 10, the screw body (37) has a plurality of passages (60) extending axially inside the screw body (37). The passages (60) are formed across the barrier (55) of each unit in the body (39) of the set of conveying parts (54), if one barrier part (55) and two conveying parts (54) separated by the barrier part (55) are made into one unit.

[0062] In this case, the passages (60) are arranged at predetermined intervals (e.g., equal intervals) along the axial direction of the screw body (37). And, in the middle section along the axial direction of the screw body (37), four passages (60) extending along the axial direction of the screw body (37) are arranged at intervals of 90° in the circumferential direction of the screw body (37).

[0063] Additionally, the passage (60) is provided within the body (39) at a position eccentric from the axis (O1) of the rotation axis (38). In other words, the passage (60) is offset from the axis (O1) and is configured to revolve around the axis (O1) when the screw body (37) rotates.

[0064] As shown in FIGS. 8 and 9, the passage (60) is a hole having, for example, a circular cross-sectional shape. In order to facilitate the smooth flow of raw materials containing filler and resin, the inner diameter of the hole is set to, for example, 2 mm or more and less than 8 mm, preferably 3 mm or more and less than 5 mm. Additionally, the body (39) of the conveying section (54) and the barrier section (55) has a wall surface (61) in the shape of a tube defining the hole. That is, the passage (60) is a hole consisting only of a hollow space, and the wall surface (61) continuously surrounds the hollow passage (60) in the circumferential direction. Accordingly, the passage (60) is configured as a hollow space that allows only the flow of raw materials. In other words, there are absolutely no other elements constituting the screw body (37) inside the passage (60). Additionally, when the screw body (37) rotates, the wall surface (61) does not rotate around the axis (O1) but revolves around the axis (O1).

[0065] As shown in FIGS. 5, 6, and 11, each passage (60) has an inlet (62), an outlet (63), and a passage body (64) connecting the inlet (62) and the outlet (63). The inlet (62) and the outlet (63) are provided separated from both sides of a single barrier section (55). Specifically, in the conveying section (54) adjacent to the base end of the screw body (37) with respect to the barrier section (55), the inlet (62) is opened on the outer surface near the downstream end of the conveying section (54). Additionally, in the conveying section (54) adjacent to the front end of the screw body (37) with respect to the barrier section (55), the outlet (63) is opened on the outer surface near the upstream end of the conveying section (54).

[0066] The passage body (64) extends in a straight line along the axial direction of the screw body (37) without branching out in the middle. As an example, the drawing shows the passage body (64) extending parallel to the axis (O1). Both sides of the passage body (64) are closed in the axial direction.

[0067] The inlet (62) is provided on one side of the passage body (64), that is, on the base side of the screw body (37). In this case, the inlet (62) may be opened to the outer surface of the screw body (37) from the end surface on one side of the passage body (64), or it may be opened to the outer surface of the screw body (37) from the end surface side on one side of the passage body (64), that is, the front part of the end surface. In addition, the opening direction of the inlet (62) is not limited to a direction perpendicular to the axis (O1), but may also be a direction intersecting the axis (O1). In this case, it may be opened in multiple directions from one side of the passage body (64), and accordingly, multiple inlets (62) may be provided.

[0068] In a different way of understanding, the inlet (62) is opened on the outer surface of the conveying section (54), which is spaced apart from the barrier section (55) in the direction of the base of the screw body (37) for each unit. It is preferable that the inlet (62) be provided on the outer surface of the tube (39) constituting the conveying section (54) at the position furthest from the direction of the base of the screw body (37). Accordingly, the inlet (62) is located immediately in front of the adjacent barrier section (55) in the direction of the base of the screw body (37) with respect to the conveying section (54) where the inlet (62) is opened.

[0069] The outlet (63) is provided on the other side of the passage body (64) (opposite to the one side), that is, on the front end portion of the screw body (37). In this case, the outlet (63) may be opened to the outer surface of the screw body (37) from the end surface on the other side of the passage body (64), or it may be opened to the outer surface of the screw body (37) from the end surface portion on the other side of the passage body (64), that is, the front portion of the end surface. In addition, the opening direction of the outlet (63) is not limited to a direction perpendicular to the axis (O1), but may also be a direction intersecting the axis (O1). In this case, it may be opened in multiple directions from one side of the passage body (64), and accordingly, multiple outlets (63) may be provided.

[0070] In a different way of grasping, the outlet (63) is opened on the outer surface of the conveying section (54), which is separated from the barrier section (55) in the direction of the front end of the screw body (37) for each of the above-mentioned units. It is preferable that the outlet (63) be provided at the position furthest from the direction of the front end of the screw body (37) on the outer surface of the body (39) constituting the conveying section (54). Accordingly, the outlet (63) is located immediately in front of the adjacent barrier section (55) in the direction of the front end of the screw body (37) with respect to the conveying section (54) in which the outlet (63) is opened.

[0071] The passage body (64) connecting the entrance (62) and the exit (63) has a length that spans between two conveying sections (54) with the barrier section (55) in between, along with a diameter that crosses the barrier section (55) for each unit. In this case, the diameter of the passage body (64) may be set smaller than the diameters of the entrance (62) and the exit (63), or may be set to the same diameter. In either case, the passage cross-sectional area defined by the diameter of the passage body (64) is set to be much smaller than the circular cross-sectional area along the diameter direction of the aforementioned circular conveying path (53).

[0072] According to the continuous high-shear processing device (1) of this configuration, the first extruder (2) preliminarily mixes the filler and the resin. The filler and resin melted by this mixing become a fluid raw material and are continuously supplied from the first extruder (2) to the conveyor (53) through the supply port (34) of the second extruder (3).

[0073] The raw material supplied to the second extruder (3) is fed into the outer surface of the conveying section (54) located on the base side of the screw body (37), as indicated by arrow B in FIG. 10. At this time, when the screw (21) rotates left in a counterclockwise direction when viewed from the base of the screw body (37), the flight (56) of the conveying section (54) continuously conveys the raw material toward the barrier section (55) adjacent to the base of the screw body (37), as indicated by the solid line arrow in FIG. 10.

[0074] At this time, a shearing action is imparted to the raw material by the difference in speed between the flight (56) rotating along the return path (53) and the inner surface of the cylinder part (33), and the raw material is stirred by the subtle twisting of the flight (56). As a result, the raw material is thoroughly mixed, and the dispersion of the filler within the resin, which is a polymer component of the raw material, proceeds.

[0075] The raw material subjected to shear action reaches the boundary between the conveying section (54) and the barrier section (55) along the conveying path (53). The flight (57) of the barrier section (55) is twisted to the right so that when the screw (21) turns left, the raw material is conveyed from the base of the screw body (37) toward the tip. As a result, the conveying of the raw material is blocked by the flight (57). In other words, the flight (57) of the barrier section (55) prevents the raw material from passing through the clearance between the barrier section (55) and the inner surface of the cylinder section (33) by restricting the flow of the raw material conveyed by the flight (56) when the screw (21) turns left.

[0076] At this time, the pressure of the raw material increases at the boundary between the conveying section (54) and the barrier section (55). Specifically, FIG. 11 shows the filling rate of the raw material at the location corresponding to the conveying section (54) of the screw body (37) in the conveying path (53) as a gradient. That is, in the conveying path (53), the filling rate of the raw material increases as the color tone becomes darker. As is clear from FIG. 11, in the conveying path (53) corresponding to the conveying section (54), the filling rate of the raw material increases as it approaches the barrier section (55), and the filling rate of the raw material becomes 100% right before the barrier section (55).

[0077] Because of this, a “raw material pool (R)” is formed right in front of the barrier section (55) where the filling rate of the raw material becomes 100%. In the raw material pool (R), the flow of the raw material is blocked, and the pressure of the raw material increases. The raw material with increased pressure is continuously introduced into the passage body (64) from the inlet (62) opened on the outer circumference of the conveying section (54), as indicated by the dashed arrow in FIGS. 10 and FIGS. 11, and flows continuously through the passage body (64) from the base of the screw body (37) toward the tip.

[0078] As described above, the cross-sectional area of ​​the passage defined by the diameter of the passage body (64) is much smaller than the annular cross-sectional area of ​​the return path (53) following the diameter direction of the cylinder part (33). Alternatively, the expansion area based on the diameter of the passage body (64) is much smaller than the expansion area of ​​the annular return path (53). Because of this, when the raw material flows from the inlet (62) into the passage body (64), the raw material is rapidly narrowed, thereby imparting an elongation effect to the raw material.

[0079] In addition, since the cross-sectional area of ​​the passage is sufficiently smaller than the cross-sectional area of ​​the ring, the raw material accumulated in the raw material pool (R) does not disappear. That is, a portion of the raw material accumulated in the raw material pool (R) is continuously flowed into the inlet (62). Meanwhile, new raw material is sent toward the barrier section (55) by the flight (56). As a result, the filling rate immediately in front of the barrier section (55) in the raw material pool (R) is always maintained at 100%. At this time, even if there is a slight fluctuation in the amount of raw material returned by the flight (56), the fluctuation is absorbed by the raw material remaining in the raw material pool (R). Accordingly, the raw material can be supplied to the passage (60) continuously and stably. Therefore, in the passage (60), a continuous extension action can be imparted to the raw material.

[0080] The raw material passing through the passage body (64) flows out from the outlet (63), as indicated by the solid arrow in FIG. 11. Accordingly, the raw material is continuously guided onto another conveying section (54) adjacent to the front end of the screw body (37) with respect to the barrier section (55). The guided raw material is continuously conveyed in the front end direction of the screw body (37) by the flight (56) of the conveying section (54), and undergoes a shearing action again during this conveying process. The raw material that has undergone the shearing action is continuously introduced into the passage body (64) from the inlet (62) and undergoes an elongation action again during the process of circulating through the passage body (64).

[0081] In this embodiment, a plurality of conveying sections (54) and a plurality of barrier sections (55) are alternately arranged along the axial direction of the screw body (37), and a plurality of passages (60) are spaced apart along the axial direction of the screw body (37). Because of this, the raw material fed into the screw body (37) from the supply port (34) is continuously conveyed from the base end to the tip end of the screw body (37) while undergoing alternating shearing and elongation actions, as indicated by the arrows in FIGS. 10 and 11. Therefore, the degree of mixing of the raw material is enhanced, and the dispersion of the filler in the resin of the raw material is promoted.

[0082] The raw material reaching the tip of the screw body (37) becomes a sufficiently mixed material and is discharged from the outlet (63) of the passage (60). The discharged material is continuously conveyed to the gap between the cylinder part (33) and the head part (36) by the flight (58) of the discharge conveying part (59), and then continuously supplied to the third extruder (4) from the discharge port (36a).

[0083] In the third extruder (4), as previously described, gaseous substances or other volatile components contained in the mixture are continuously removed from the mixture. The mixture from which gaseous substances or other volatile components have been removed is continuously discharged out of the high-shear processing device (1) through the discharge port (28) of the head section (27). The discharged mixture is immersed in cooling water accumulated in a water tank. Accordingly, the mixture is forcibly cooled, and a resin molded product of the desired conductive composite material can be obtained.

[0084] According to the first embodiment, in the second extruder (3), the raw material supplied from the first extruder (2) is conveyed while repeatedly reversing in the axial direction of the screw body (37) multiple times, and during this conveying process, shearing and elongation actions are repeatedly applied to the raw material. In other words, since the raw material does not circulate multiple times at the same location on the outer surface of the screw body (37), the raw material can be continuously supplied from the second extruder (3) to the third extruder (4).

[0085] Accordingly, sufficiently kneaded mixture can be continuously molded, and compared to a batch extruder, the production efficiency of the mixture can be dramatically increased.

[0086] In addition, in this embodiment, the resin pre-mixed in the first extruder (2) is continuously supplied to the second extruder (3). Because of this, the flow of resin inside the first extruder (2) is not temporarily blocked. Accordingly, temperature changes, viscosity changes, or phase changes of the resin caused by the mixing resin blocking inside the first extruder (2) can be prevented. As a result, raw materials of uniform quality can always be supplied from the first extruder (2) to the second extruder (3).

[0087] In addition, according to the first embodiment, rather than continuous production in appearance, complete continuous production of the mixture becomes possible. That is, while continuously conveying the raw material from the first extruder (2) to the second extruder (3) and the third extruder (4), alternating shearing and elongation actions can be applied to the raw material in the second extruder (3). With this configuration, the raw material in a molten state is stably supplied from the first extruder (2) to the second extruder (3).

[0088] In addition, according to the first embodiment, in full continuous production, the operating conditions of the first extruder (2) and the second extruder (3) can be mutually correlated, and each can be set to an optimal operating condition. For example, when pre-mixing the resin in the first extruder (2), the screw rotation speed can be operated at a conventional speed of 100 rpm to 300 rpm. Because of this, sufficient heating and melting of the resin, and pre-mixing, become possible. Meanwhile, the second extruder (3) can rotate the screw (21) at a speed of 100 rpm to 1000 rpm. Because of this, shearing and elongating actions can be effectively applied alternately to the filler and the resin.

[0089] Accordingly, the first extruder (2) and the second extruder (3) may be equipped with screws according to their respective roles or functions. That is, in the case of the first extruder (2), screws (7a, 7b) according to the role or function of pre-mixing the supplied material may be provided. Meanwhile, in the case of the second extruder (3), screws (21) according to the role or function of imparting shearing and elongation actions to the molten raw material supplied from the first extruder (2) may be provided. Accordingly, the lengthening of the first extruder (2) and the second extruder (3) can be prevented.

[0090] In addition, since the screw (21) does not have a plasticizing zone as provided by the screw of a conventional single-axis extruder and is configured by combining a conveying section (54), a barrier section (55), and a passage (60), the second extruder (3) can be easily operated.

[0091] And, by setting the diameter of the screw (21) to a constant value over the entire length of the screw (21), the conveying path (53) for conveying raw materials has a uniform annular cross-sectional shape over the entire length of the screw (21), and when alternately applying shearing and elongation actions to the raw materials, they can be applied smoothly in sequence, thereby enabling uniform mixing.

[0092] According to the first embodiment, the passage (60) that imparts an elongation action to the raw material extends in the axial direction of the screw body (37) at an eccentric position with respect to the axis (O1) which is the rotational center of the screw body (37), so the passage (60) revolves around the axis (O1). In other words, the tube-shaped wall surface (61) defining the passage (60) does not rotate around the axis (O1) but revolves around the axis (O1).

[0093] For this reason, when the raw material passes through the passage (60), the raw material receives centrifugal force, but the raw material is not actively stirred inside the passage (60). Therefore, the raw material passing through the passage (60) is less likely to receive a shearing action, and the raw material returning to the outer surface of the return section (54) after passing through the passage (60) mainly receives an elongation action.

[0094] Accordingly, according to the screw (21) of the first embodiment, the location for applying a shearing action to the raw material and the location for applying an elongation action to the raw material can be clearly determined. In this respect, it is a configuration that is advantageous for verifying the degree of mixing of the raw material, and the degree of mixing can be controlled with high precision. As a result, it becomes possible to produce a mixed material having a microscopic dispersion structure in which the filler is highly dispersed within the resin of the raw material.

[0095] In addition, since all of the multiple passages (60) are eccentric with respect to the axis (O1), an even elongation action can be applied to the raw material passing through the multiple passages (60). That is, the non-uniformity of mixing conditions between the multiple passages (60) can be eliminated, and uniform mixing can be performed.

[0096] [Second embodiment]

[0097] FIG. 12 discloses a second embodiment. The second embodiment differs from the first embodiment in matters concerning the rotation shaft (38). The configuration of the screw (21) other than that is basically the same as the first embodiment. Therefore, in the second embodiment, the same reference numerals are used for the same components as in the first embodiment, and their descriptions are omitted.

[0098] As shown in FIG. 12, a refrigerant passage (71) is formed inside the rotating shaft (38). The refrigerant passage (71) extends coaxially along the axis (O1) of the rotating shaft (38). One end of the refrigerant passage (71) is connected to an outlet pipe (73) through a rotary joint (72) at the joint (42). The other end of the refrigerant passage (71) is liquid-tightly sealed at the tip of the rotating shaft (38).

[0099] A refrigerant inlet pipe (74) is inserted coaxially into the interior of the refrigerant passage (71). One end of the refrigerant inlet pipe (74) is connected to the inlet pipe (75) through a rotary joint (72). The other end of the refrigerant inlet pipe (74) is opened into the refrigerant passage (71) near the other end of the refrigerant passage (71).

[0100] In the second embodiment, a refrigerant such as water or oil is sent from the inlet pipe (75) to the refrigerant passage (71) through the rotary joint (72) and the refrigerant introduction pipe (74). The refrigerant sent to the refrigerant passage (71) passes through the gap between the inner surface of the refrigerant passage (71) and the outer surface of the refrigerant introduction pipe (74) and returns to the joint (42) of the rotating shaft (38), and is also returned to the outlet pipe (73) through the rotary joint (72).

[0101] According to the second embodiment, since the refrigerant circulates along the axial direction of the rotating shaft (38), the screw body (37) can be cooled using the refrigerant. Because of this, the temperature of the screw body (37) in contact with the raw material can be appropriately controlled, thereby preventing the deterioration of the resin and changes in viscosity caused by the rise in the temperature of the raw material.

[0102] [Third Embodiment]

[0103] FIGS. 13 to 18 disclose a third embodiment. The third embodiment differs from the first embodiment in matters concerning the screw body (37). The configuration of the screw (21) other than that is basically the same as the first embodiment. Therefore, in the third embodiment, the same reference numerals are used for the same components as in the first embodiment, and their descriptions are omitted.

[0104] As shown in FIGS. 13 to 16, the screw body (37) has a plurality of conveying sections (81) for conveying raw materials and a plurality of barrier sections (82) for restricting the flow of raw materials. That is, a plurality of conveying sections (81) are arranged at the base of the screw body (37) corresponding to one end of the barrel (20), and a plurality of conveying sections (81) are arranged at the front end of the screw body (37) corresponding to the other end of the barrel (20). In addition, between these conveying sections (81), the conveying sections (81) and the barrier sections (82) are arranged alternately in the axial direction from the base of the screw body (37) toward the front end.

[0105] Additionally, the supply port (34) of the barrel (20) is open toward the return section (81) positioned on the side of the base of the screw body (37).

[0106] Each conveying section (81) has a flight (84) twisted in a spiral shape. The flight (84) protrudes toward the conveying path (53) from the outer surface along the circumferential direction of the body (39). The flight (84) is twisted so as to convey raw material from the base of the screw body (37) toward the tip when the screw (21) is rotated left in a counterclockwise direction when viewed from the base of the screw body (37). That is, the flight (84) is twisted to the right, like a right-hand screw.

[0107] Each barrier section (82) has a flight (86) that is twisted in a spiral shape. The flight (86) protrudes toward the conveying path (53) from the outer surface along the circumferential direction of the body (39). The flight (86) is twisted so that when the screw (21) is rotated left in a counterclockwise direction when viewed from the base of the screw body (37), the raw material is conveyed from the tip of the screw body (37) toward the base. That is, the flight (86) is twisted to the left, like a left-hand screw, in the twisting direction of the flight (86).

[0108] The twist pitch of the flight (86) of each barrier section (82) is set to be equal to or smaller than the twist pitch of the flight (84) of the return section (81). Additionally, a small clearance is secured between the top section of the flight (84, 86) and the inner surface of the cylinder section (33) of the barrel (20).

[0109] As shown in FIGS. 13, 14, and 17, the screw body (37) has a plurality of passages (88) extending in the axial direction of the screw body (37). The passages (88) are formed across the barrier (55) of each unit in the body (39) of both conveying sections (81), if a barrier section (82) and two conveying sections (81) separated by the barrier section (82) are made into a single unit. In this case, the passages (88) are aligned in a line with a predetermined gap (e.g., equal gap) along the same straight line along the axial direction of the screw body (37).

[0110] Additionally, the passage (88) is provided within the body (39) at an eccentric position from the axis (O1) of the rotation axis (38). In other words, the passage (88) is offset from the axis (O1) and is configured to revolve around the axis (O1) when the screw body (37) rotates.

[0111] As shown in FIG. 15, the passage (88) is a hole having, for example, a circular cross-sectional shape. The passage (88) is configured as a hollow space that allows only the flow of raw materials. When the screw body (37) rotates, the wall surface (89) of the passage (88) does not rotate around the axis (O1) but revolves around the axis (O1).

[0112] As shown in FIGS. 13, 14, and 18, each passage (88) has an inlet (91), an outlet (92), and a passage body (93) connecting the inlet (91) and the outlet (92). The inlet (91) and the outlet (92) are provided in close proximity to both sides of a single barrier section (82). Alternatively, in a single conveyor section (81) adjacent between two adjacent barrier sections (82), the inlet (91) is opened on the outer surface near the downstream end of the conveyor section (81), and the outlet (92) is opened on the outer surface near the upstream end of the conveyor section (81). The inlet (91) and the outlet (92) that are opened on the outer surface of the conveyor section (81) are not connected by the passage body (93). The inlet (91) is connected to the outlet (92) of the adjacent downstream return section (81) through the barrier section (82), and the outlet (92) is connected to the inlet (91) of the adjacent upstream return section (81) through the barrier section (82).

[0113] The raw material supplied to the second extruder (3) is fed into the outer surface of the conveying section (81) located on the side of the base of the screw body (37), as indicated by arrow C in FIG. 17. At this time, when the screw (21) rotates left in a counterclockwise direction when viewed from the base of the screw body (37), the flight (84) of the conveying section (81) continuously conveys the raw material toward the front end of the screw body (37), as indicated by the solid line arrow in FIG. 17.

[0114] In this embodiment, a plurality of conveying sections (81) and a plurality of barrier sections (82) are alternately arranged along the axial direction of the screw body (37), and a plurality of passages (88) are spaced apart along the axial direction of the screw body (37). Because of this, the raw material fed into the screw body (37) from the supply port (34) is continuously conveyed from the base to the tip of the screw body (37) while undergoing alternating shearing and elongation actions, as indicated by the arrows in FIGS. 17 and 18. Therefore, the degree of mixing of the raw material is enhanced, and the dispersion of the conductive filler in the thermoplastic elastomer of the raw material is promoted.

[0115] In this embodiment, as shown in FIG. 17, the direction of transport of the raw material in the transport section (81) indicated by the solid arrow and the direction of flow of the raw material within the passage (88) indicated by the dashed arrow are the same. In addition, the inlet (91) of the passage (88) is provided near the end of the downstream side (front end side, left side toward FIG. 17) of the transport section (81), and the outlet (92) is provided near the end of the upstream side of the downstream transport section (81) adjacent through the barrier section (82). As such, since the length (L2) of the passage (88) over the barrier section (82) is configured to be short, the flow resistance when the raw material passes through the passage (88) is reduced. Therefore, this embodiment is suitable for a method of manufacturing resin using a raw material with high viscosity. Generally, when the raw material contains a filler, the viscosity in the heated melt state tends to be higher compared to a raw material consisting only of resin. For this reason, the present embodiment is suitable for a method of manufacturing a conductive composite material using a raw material comprising a conductive filler and a thermoplastic elastomer.

[0116] The length (L2) of the passage (88) needs to be greater than the length (L1) of the barrier portion (82) over which the passage (88) spans, but from the perspective of lowering the flow resistance when the raw material passes through the passage (88), it is preferable that the length (L1) of the barrier portion (82) over which the passage (88) spans be 2 times or less, more preferable that it be 1.5 times or less, and more preferable that it be 1.3 times or less.

[0117] Then, the raw material reaching the tip of the screw body (37) becomes a sufficiently mixed mixture, which is continuously supplied to the third extruder (4) from the discharge port (36a), and gaseous substances or other volatile components contained in the mixture are continuously removed from the mixture.

[0118] [Fourth embodiment]

[0119] FIGS. 19 to 27 disclose a fourth embodiment. The fourth embodiment differs from the first embodiment in matters concerning the screw body (37). The configuration of the screw (21) other than that is basically the same as the first embodiment. Therefore, in the fourth embodiment, the same reference numerals are used for the same components as in the first embodiment, and their descriptions are omitted.

[0120] As shown in FIGS. 19 to 21, the screw body (37) has a plurality of conveying sections (101) for conveying raw materials, a plurality of barrier sections (102) for restricting the flow of raw materials, and a plurality of circulation sections (103) for temporarily circulating raw materials. That is, a plurality of conveying sections (101) are arranged at the base of the screw body (37) corresponding to one end of the barrel (20), and a plurality of conveying sections (101) are arranged at the front end of the screw body (37) corresponding to the other end of the barrel (20). In addition, between these conveying sections (101), the circulation section (103) and the barrier section (102) are alternately arranged in the axial direction from the base of the screw body (37) toward the front end.

[0121] Additionally, the supply port (34) of the barrel (20) is open toward the conveying part (101) positioned on the side of the base of the screw body (37).

[0122] Each conveying section (101) has a flight (105) twisted in a spiral shape. The flight (105) protrudes toward the conveying path (53) from the outer surface along the circumferential direction of the body (39). The flight (105) is twisted so as to convey raw material from the base of the screw body (37) toward the tip when the screw (21) is rotated left in a counterclockwise direction when viewed from the base of the screw body (37). That is, the flight (105) is twisted to the right, like a right-hand screw.

[0123] Each barrier section (102) has a flight (107) that is twisted in a spiral shape. The flight (107) protrudes toward the conveying path (53) from the outer surface along the circumferential direction of the body (39). The flight (107) is twisted so that when the screw (21) is rotated left in a counterclockwise direction when viewed from the base of the screw body (37), the raw material is conveyed from the tip of the screw body (37) toward the base. That is, the flight (107) is twisted to the left, like a left-hand screw, in the twisting direction of the flight (107).

[0124] The circulation section (103) is adjacent to the barrier section (102) from the side of the base of the rotation axis (38). Each circulation section (103) has first to third flights (110, 111, 112) that are twisted in a spiral shape. The first to third flights (110, 111, 112) each protrude toward the return path (53) from the outer surface along the circumferential direction of the body (39).

[0125] The first to third flights (110, 111, 112) are arranged adjacent to each other along the axial direction of the screw body (37). When viewed from the base of the screw body (37), the screw (21) is rotated left in a counterclockwise direction and is twisted to convey raw material from the base of the screw body (37) toward the tip. That is, the first to third flights (110, 111, 112) are twisted to the right, like a right-hand screw.

[0126] In this case, the twist pitch of the flight (107) of each barrier section (102) is set to be equal to or smaller than the twist pitch of the flight (105) of the return section (101) and the flight (110, 111, 112) of the circulation section (103). Additionally, the twist pitch of the second flight (111) is set to be smaller than the twist pitch of the first and third flights (110, 112). Furthermore, a small clearance is secured between the top section of the flight (105, 107, 110, 111, 112) and the inner surface of the cylinder section (33) of the barrel (20).

[0127] Additionally, in the first to third flights (110, 111, 112), the third flight (112) is positioned upstream of the return direction, and the first flight (110) is positioned downstream of the return direction. The second flight (111) is positioned between the third flight (112) and the first flight (110).

[0128] In this embodiment, each barrier section (102) is designed so that raw material can flow over each barrier section (102). Specifically, each barrier section (102) is designed so that raw material can pass between each barrier section (102) and the cylinder section (33) when the screw (21) is rotatably inserted into the cylinder section (33) of the barrel (20). In this case, it is preferable to set the clearance between the outer diameter section (top section of the flight (107)) of each barrier section (102) and the inner surface of the cylinder section (33) to a range of 0.1 mm or more and 3 mm or less. More preferably, the clearance is set to a range of 0.1 mm or more and 1.5 mm or less.

[0129] As shown in FIGS. 19, 20, and 27, each passage (115) has an inlet (117), an outlet (118), and a passage body (119) connecting the inlet (117) and the outlet (118). The inlet (117) and the outlet (118) are opened on the outer surface of the tube (39) constituting the circulation section (103). An example of a passage (115) is shown in the drawings. In the passage (115), the passage body (119) is provided in the tube (39) in which the first flight (110) is formed, and the inlet (117) and the outlet (118) are opened on the outer surface of the tube (39). The opening positions of the inlet (117) and the outlet (118) can be freely set within the range of the outer surface of the tube (39).

[0130] The passage body (119) extends in a straight line along the axial direction of the screw body (37) without branching out in the middle. As an example, the drawing shows the passage body (119) extending parallel to the axis (O1). Both sides of the passage body (119) are closed in the axial direction.

[0131] The entrance (117) is provided on one side of the passage body (119), that is, on the front side of the screw body (37).

[0132] The exit (118) is provided on the other side of the passage body (119) (opposite to the one side), that is, on the base side of the screw body (37).

[0133] As shown in FIG. 22, the passage (115) is a hole having, for example, a circular cross-sectional shape. The passage (115) is configured as a hollow space that allows only the flow of raw materials. The wall surface (116) of the passage (115) does not rotate around the axis (O1) but revolves around the axis (O1) when the screw body (37) rotates.

[0134] The raw material supplied to the second extruder (3) is fed into the outer surface of the conveying section (101) located on the side of the base of the screw body (37), as indicated by arrow D in FIG. 26. At this time, when the screw (21) rotates left in a counterclockwise direction when viewed from the base of the screw body (37), the flight (105) of the conveying section (101) continuously conveys the raw material toward the front end of the screw body (37), as indicated by the solid line arrow in FIG. 26.

[0135] In this embodiment, a portion of the raw material returned toward the barrier section (102) is continuously guided from the inlet (117) to the passage (115) and temporarily repeats circulation at the location of the circulation section (103). The remaining raw material returned toward the barrier section (102) passes through the clearance between the top part of the flight (107) of the barrier section (102) and the inner surface of the cylinder section (33) and is continuously flowed into the adjacent circulation section (103).

[0136] [Fifth embodiment]

[0137] FIG. 28 discloses a fifth embodiment. In the first embodiment described above, the case where the first extruder (processor) (2) is configured as a twin-screw mixer was described, but instead, in the fifth embodiment, the case where the first extruder (2) is configured as a single-screw extruder is assumed.

[0138] As shown in FIG. 28, in the first extruder (2) according to the fifth embodiment, the barrel (6) is provided with a cylinder portion (8) that rotatably accommodates a single screw (7). The barrel (6) is provided with, as in the first embodiment described above, a supply port (9) capable of supplying, for example, pelletized material into the cylinder portion (8), a heater (not shown) for melting the resin, and a discharge port (6a) capable of discharging the molten resin.

[0139] The screw (7) is rotatable around an axis (O2), and a flight (122) twisted in a spiral shape is formed on its outer surface. The flight (122) is configured to continuously convey the resin supplied from the supply port (9) toward the discharge port (6a). For this reason, the flight (122) is twisted in the opposite direction to the rotation direction of the screw (7) when viewed from the side of the supply port (9). As an example, the flight (122) is shown in the drawing when the screw (7) is rotated to the left to convey the resin. In this case, the twist direction of the flight (122) is set clockwise, like a right-hand screw.

[0140] Additionally, on the outer surface of the screw (7), a supply section (P1), a compression section (P2), and a conveying section (P3) are continuously configured in sequence from the side of the supply port (9) toward the discharge port (6a). The supply section (P1) has a cylindrical shape, and the gap between its outer surface (7-P1) and the cylinder section (8) is set wide. The conveying section (P3) has a cylindrical shape, and the gap between its outer surface (7-P3) and the cylinder section (8) is set narrowly. In other words, by narrowing the gap between the outer surface (7-P3) and the cylinder section (8) in the conveying section (P3), the height of the flight (122) is set low. Accordingly, the discharge stability at the discharge port (6a) is improved. The compression section (P2) has a fan shape extending from the supply section (P1) toward the return section (P3), and the gap between the outer surface (7-P2) and the cylinder section (8) is set to continuously narrow from the supply section (P1) toward the return section (P3).

[0141] Here, with the screw (7) rotated to the left, the pellet-shaped resin supplied from the supply port (9) to the cylinder section (8) is conveyed by the flight (122) in the order of supply section (P1), compression section (P2), and conveying section (P3), and then discharged from the discharge port (6a). In the supply section (P1), the resin is in a solid state due to its low temperature. In the compression section (P2), the resin is mainly heated by a heater and continuously compressed from the narrowed gap. In the conveying section (P3), the resin is melted to form a mixed raw material. Then, the raw material discharged from the discharge port (6a) of the barrel (6) is continuously supplied to the second extruder (3), as indicated by arrow A in FIG. 1.

[0142] According to the above fifth embodiment, even when the first extruder (2) is a single-screw extruder, raw materials with a viscosity optimized for mixing treatment by the second extruder (3) can be produced, just as in the case of the twin-screw kneader according to the first embodiment. Accordingly, the burden on the second extruder (3) can be reduced.

[0143] For example, if we assume a case where shearing and elongating actions are alternately applied to a material that has already undergone preliminary mixing, that is, a material in which a filler (additive) is kneaded into a resin and formed into pellets, the material can be mixed without causing deterioration of the physical properties of the additive or breakage of the fibers by using a single-screw extruder.

[0144] In addition, when an additive is added to the raw material, if the additive is fed into the first extruder (2) or the second extruder (3), there is a possibility that the physical properties of the additive may deteriorate or decompose due to high-speed rotation in the second extruder (3). In this case, by making the third extruder (4) a twin-screw extruder, not only degassing but also mixing (kneading) of the additive into the raw material becomes possible.

[0145] [Example]

[0146] [Example 1]

[0147] In the mixing device according to the first embodiment, the direction of conveyance of the raw material in the conveying section and the direction of flow of the raw material within the passage are opposite, and the inlet and outlet of the passage over the barrier section are provided in this order at the front end of the conveying section and the front end of the adjacent conveying section. Because of this, the length of the passage increases, and the flow resistance increases when the raw material passes through; therefore, in the case of high-viscosity raw material, it is difficult to mix while allowing it to pass smoothly through the passage.

[0148] Therefore, in this embodiment, a mixing device according to a third embodiment was used, wherein the direction of the raw material's return in the return section and the direction of its flow within the passage are the same, and the inlet and outlet of the passage spanning the barrier section are provided in this order at the leading end of the return section and the lower end of the adjacent return section. Since the passage is short and the flow resistance is low, this mixing device is suitable for mixing high-viscosity raw materials.

[0149] A conductive composite material was manufactured by mixing raw materials consisting of a conductive filler and a thermoplastic elastomer using a mixing device according to the third embodiment, by alternately applying shearing and elongation actions.

[0150] In the manufacture of a conductive composite material, two types of materials, multilayer carbon nanotubes (CNT) as a conductive filler and hydrogenated styrene-based thermoplastic elastomer (SEBS) as a thermoplastic elastomer, were supplied to a first extruder (2) in which the effective length (L / D) of the mixing section (12) relative to the screw effective length (L / D) (48) was set to 8, and a molten material was produced by preliminarily mixing. Then, the molten material was continuously supplied from the first extruder (2) to the second extruder (3) as a raw material for the second extruder (3), and a conductive composite material was manufactured.

[0151] The specifications of the screw (21), etc., equipped in the second extruder (3) were set as follows.

[0152] Screw diameter (outer): 48 mm

[0153] Screw effective length (L / D): 6.25–18.75

[0154] Screw rotation speed: 200rpm, 300rpm, 400rpm, 500rpm, 600rpm, or 1000rpm

[0155] Raw material supply: 10 kg / hour

[0156] Barrel set temperature: 250℃

[0157] Cross-sectional shape of the inlet, outlet, and passage body: Circular with a diameter of 4 mm

[0158] Number of times the passageway is passed (number of repetitions): 2, 6, or 12 times

[0159] CNT concentration in raw material: 1 wt%

[0160] A conductive composite material was manufactured using the above-mentioned mixing device, and the conductivity of the obtained conductive composite material was measured in accordance with JIS K 7194. The results are shown in Table 1.

[0161] Three test specimens for measuring conductivity were prepared using a hot press device under the following conditions. Conductivity was measured at 5 points for each test specimen using a low-resistance resistivity meter. Since 5 resistivity values ​​are obtained from one test specimen, 15 resistivity values ​​are obtained. The average value of these 15 resistivity values ​​was taken as the conductivity.

[0162] Production conditions: Temperature 260℃, Press pressure 49 MPa

[0163] Test specimen: Length 80 mm, width 50 mm, thickness 0.5 mm

[0164] [Table 1]

[0165]

[0166] As shown in Table 1 and the graph in Fig. 29, it was possible to manufacture a conductive composite material with high conductivity regardless of the screw rotation speed. Furthermore, when the screw rotation speed was set to 1000 rpm (revolutions / min), a conductive composite material with high conductivity was obtained regardless of the number of times the raw material passed through the passage. Therefore, it can be said that it is desirable to set the screw rotation speed to approximately 1000 rpm in order to manufacture a conductive composite material having high conductivity. However, if the screw rotation speed for mixing raw materials consisting of 1 wt% CNT and 99 wt% SEBS is set to 1000 rpm, the temperature of the raw materials becomes excessively high during the mixing process, which causes a decrease in the strength of the conductive composite material. Therefore, when using CNT and SEBS as raw materials, it is desirable to set the screw rotation speed for mixing the raw materials to 600 rpm or less.

[0167] As described above, since the conductivity of the conductive composite material is not affected by the rotational speed of the screw, a conductive composite material with high conductivity is obtained even when the rotational speed of the screw is 600 rpm or less. However, when the rotational speed of the screw is set to approximately 200 rpm to 600 rpm, it became clear that the conductivity of the obtained conductive composite material differs depending on the number of times the raw material passes through the passage, as shown in FIG. 29. In other words, when the rotational speed of the screw is set to approximately 200 rpm to 600 rpm, it was found that the conductivity of the conductive composite material is affected by the number of times it passes through the passage.

[0168] In the present embodiment, the mixing device used, in which the inlet, outlet, and body of the passage have a circular cross-sectional shape and are formed as a circle with an inner diameter of 4 mm, allowed the molten raw material to pass through the passage smoothly. However, in the mixing device in which the inlet, outlet, and the inner diameter of the hole of the passage body have a circular shape of 2 mm, the raw material could not pass through the passage smoothly. Therefore, when the inlet, outlet, and body of the passage have a circular cross-sectional shape, a diameter of 2 mm or more is preferable, a diameter of 3 mm or more is more preferable, and a diameter of 4 mm or more is more preferable.

[0169] [Example 2]

[0170] Using a mixing device similar to that of Example 1, the screw rotation speed was fixed at 400 rpm, and the number of times the material passed through the passage was set to 4, 8, and 10 times to produce a conductive composite material, and the conductivity of the obtained conductive composite material was measured in the same manner as in Example 1.

[0171] [Table 2]

[0172]

[0173] Table 2 and the graph in Figure 30 summarize the measurement results of the conductivity of the conductive composite materials obtained in Example 1 and Example 2. By increasing the number of times the material passes through the channel from 2 to 4, the conductivity of the obtained conductive composite material increases rapidly. This is thought to be due to the increased dispersibility of CNTs in SEBS by increasing the number of times the material passes through the channel. From these results, it can be said that in order to obtain a conductive composite material with high conductivity, the number of times the material passes through the channel is preferably 2 or more, more preferably 3 or more, and more preferably 4 or more.

[0174] In addition, the conductivity of the resulting conductive composite material decreases as the number of passages through the channel is increased from 10 to 12. This is thought to be because increasing the number of passages through the channel caused a decrease in the function of the CNTs dispersed in SEBS as conductive fillers. From this result, it can be said that in order to obtain a conductive composite material with high conductivity, it is desirable to have the number of passages through the channel 16 times or less, more desirable to have it 11 times or less, and even more desirable to have it 10 times or less.

[0175] As described above, it was found that the number of times the raw material passes through the passage in the manufacturing method of the present invention affects the dispersibility of the CNT and the conductive function of the conductive filler. In order to manufacture a conductive composite material with high conductivity by highly dispersing the CNT in SEBS while maintaining its function as a conductive filler, it is preferable that the number of times the material passes through the passage be 3 times or more and 11 times or less, and more preferable that it be 4 times or more and 10 times or less.

[0176] [Example 3]

[0177] The screw rotation speed of the mixing device, similar to Example 1, was fixed at 400 rpm, and the number of times the material passed through the passage and the concentration of CNTs in the material were varied as follows to produce a conductive composite material and measure the conductivity. The results are shown in Table 3.

[0178] Number of times the passageway was passed: 4, 6, 8, 10, 12 times

[0179] CNT concentration in material: 0.50 wt%, 0.75 wt%, 1.0 wt%, 1.25 wt%, 1.5 wt%, 2.0 wt%, 3.0 wt%

[0180] [Table 3]

[0181]

[0182] As shown in Table 3 and the graph in Figure 31, when the CNT concentration in the material was 0.75 wt% or higher, a conductive composite material with high conductivity was obtained by making the number of times the material passed through the channel 4 or higher. However, when the CNT concentration in the material was 0.50 wt%, the conductive composite material with 4 times the number of times the material passed through the channel was significantly lower than that with 6 times. From this result, from the perspective of stably manufacturing a conductive composite material with high conductivity using a material with a low CNT concentration, it can be said that 5 or more times the number of times the material passed through the channel is desirable, and 6 or more times is more desirable.

[0183] [Example 4]

[0184] The screw rotation speed of the mixing device of Examples 1 and 2 was fixed at 400 rpm, and the number of times the passage was passed was set to 2, 4, 6, 8, 10, and 12, and the tensile strength of the obtained conductive composite material was measured in accordance with JIS K 6251. The results are shown in Table 4.

[0185] The sheet cut into the shape of the test specimen was manufactured using a hot press device, the same method used for the conductivity test specimen. The shape was set to a dumbbell type No. 3. For the tensile test, a universal testing machine (Autograph AG-50kN type manufactured by Shimadzu Seisakusho Co., Ltd.) was used, and the load was applied until the test specimen fractured, with a crosshead speed of 100 mm / min. The tensile strength was calculated using the following formula.

[0186] F = P / W × D

[0187] F: Intensity (MPa)

[0188] P: Breaking load (MPa)

[0189] W: Width of the test specimen (mm)

[0190] D: Thickness of the test specimen (mm)

[0191] [Table 4]

[0192]

[0193] As shown in Table 4 and Figure 32, the tensile strength of the conductive composite materials with 6, 8, and 10 passes is approximately the same, while the tensile strength of the conductive composite material with 12 passes decreased. From these results, it can be said that, in order to increase the tensile strength of the conductive composite material, the number of passes is preferably 11 or fewer, and 10 or fewer is more preferable.

[0194] [Example 5]

[0195] A conductive composite material was manufactured by mixing raw materials using a mixing device according to the fourth embodiment instead of a mixing device according to the third embodiment, and the conductivity of the obtained conductive composite material was measured. The results of Example 5 using the mixing device according to the fourth embodiment and the results of Example 1 using the mixing device according to the third embodiment are shown in Table 5.

[0196] The specifications of the screw (21), etc., equipped in the second extruder (3) were set as follows.

[0197] Screw diameter (outer): 36 mm

[0198] Screw Effective Length (L / D): 12.5

[0199] Screw rotation speed: 400rpm, 500rpm, 600pm

[0200] Raw material supply: 10 kg / hour

[0201] Barrel set temperature: 250℃

[0202] Shape of inlet and outlet: Circular with a diameter of 4 mm

[0203] Number of times the passageway is passed (number of repetitions): 6 times

[0204] CNT concentration in raw material: 1 wt%

[0205] [Table 5]

[0206]

[0207] FIG. 33 shows the conductivity of the conductive composite material obtained by the manufacturing method of Example 1 and Example 5. As shown in FIG. 33 and Table 5, by using the mixing device according to the third embodiment, a conductive composite material with a higher conductivity than that obtained by the mixing device according to the fourth embodiment was obtained. From this result, it can be said that using a mixing device configured according to the third embodiment, that is, among the conveying sections adjacent through the barrier section, an inlet is provided in the conveying section on the base side and an outlet is provided in the conveying section on the leading side, and a passage connecting the inlet and the outlet is provided across the barrier section, and raw materials are conveyed from the base of the screw body toward the leading side in the conveying section and flowed from the base of the screw body toward the leading side within the passage, is preferable from the perspective of manufacturing a conductive composite material having high conductivity.

[0208] [Example 6]

[0209] Among the specifications of the screw (21) and the second extruder (3), only in the configuration where the cross-sectional shape of the inlet, outlet, and passage body is circular with a diameter (inner diameter) of 2 mm, a different mixing device from the one used in Example 1 was used to manufacture a conductive composite material with 6 repetitions, and the conductivity of the obtained conductive composite material was measured in accordance with JIS K 7194. The results of Example 6, in which the cross-sectional shape of the passage is circular with a diameter of 2 mm, and the results of Example 1, in which the cross-sectional shape of the passage is circular with a diameter of 4 mm, with 6 repetitions are shown in Table 6.

[0210] [Table 6]

[0211]

[0212] As shown in Table 6 and Figure 34, Example 6 yielded a conductive material with slightly lower conductivity than the conductive composite material obtained by Example 1, similar to Example 5. This result is thought to be due to the fact that in a mixing device with a screw diameter of 48 mm, if the inner diameter of the passage cross-section is set to 2 mm, the inner diameter relative to the screw diameter is narrow, making it difficult for the resin to enter the passage; consequently, a large amount of resin accumulates in front of the barrier, causing the pressure to rise and the molten resin raw material to overflow the barrier. From this result, it can be said that in a mixing device with a screw diameter of about 30 to 50 mm, the inner diameter (diameter of the cross-sectional circle) of the passage inlet, outlet, and the main body of the passage is preferably about 3 mm or more and 5 mm or less.

[0213] From the results of Examples 5 and 6, the mixing device according to the fourth embodiment, in which the inlet and outlet of the passage are provided in the same conveying section, had a lower conductivity of the manufactured conductive material than the mixing device according to the third embodiment, in which the inlet and outlet of the passage are provided in different conveying sections adjacent through a barrier section. This is thought to be because an excessive shear force was applied to the conductive filler that had penetrated the gap between the cylinder section wall and the material by overcoming the barrier section, causing the conductive filler to be unable to maintain a state of being long and connected in a fiber shape, thereby preventing it from exhibiting conductivity. Furthermore, if the raw material penetrates the gap between the cylinder section wall and the material, an excessive shear force is applied to the resin (thermoplastic elastomer) in the raw material, causing shear heat generation, and there is a possibility that the resin itself may deteriorate. Therefore, from the perspective of manufacturing a conductive material with good tensile strength and conductivity, it is preferable to use the mixing device according to the third embodiment, in which the raw material passes through the passage and moves between conveying sections.

[0214] [Comparative Example 1]

[0215] Conductive composite materials were prepared from materials composed of CNTs and SEBS with CNT concentrations of 1.25 wt%, 2.5 wt%, and 5.0 wt% using a batch-type mixing apparatus described in Patent Document 2 (Japanese Patent Publication No. 2008-266577), and the conductivity was measured. The measurement results are shown in Table 7 along with the results of 6 repetitions of Example 3.

[0216] [Table 7]

[0217]

[0218] As shown in Table 7 and Figure 35, the conductive composite material of Comparative Example 1 had a lower conductivity than the conductive composite material of Example 3, which had the same CNT concentration. According to the manufacturing method of the present invention, it is possible to reduce the amount of CNT required to make a conductive composite material with high conductivity.

[0219] In addition, from the graphs in FIGS. 33 and FIGS. 35, the conductive composite material of Example 5, manufactured using a mixing device with a screw diameter of 36 mm, had a slightly lower conductivity than the conductive composite material of Example 3, manufactured using a mixing device with a screw diameter of 48 mm, but had a sufficiently high conductivity when compared to the batch-type mixing device of Comparative Example 1. From these results, it can be said that if the screw diameter (outer diameter) of the mixing device is in the range of 30 mm or more and 50 mm or less, a conductive composite material having equivalent conductivity can be obtained. Explanation of the symbols

[0220] 2: 1st Extruder (Processor) 3: 2nd Extruder 4: 3rd Extruder (Degassing Machine) 20: Barrel 21: Screw 34: Supply port 36a: Discharge port 37: Screw body 54, 81, 101: Return section 56, 57, 58, 84, 86, 105, 107, 110, 111, 112, 122: Flight 60, 88, 115: Passage 62, 91, 117: Entrance 63, 92, 118: Exits 64, 93, 119: Passageway Main Body 55, 82, 102: Wall section D1: Outer diameter O1, O2: Axis L1: Length of the wall section L2: Length of the passageway

Claims

Claim 1 In an extruder, a mixture produced by mixing raw materials by means of a screw is continuously discharged, and the screw has a screw body that rotates around a straight axis along the conveying direction of the raw materials, and inside the screw body, a passage is provided through which the raw materials introduced from an inlet opened on the outer surface of the screw body flow, and the raw materials conveyed along the outer surface of the screw body are restricted from conveying in a conveying section by a barrier section provided in the screw body that restricts the conveying of the raw materials, thereby forming a raw material pool where the filling rate of the raw materials becomes 100% immediately before the barrier section, so that the pressure is increased, and the raw materials in the conveying section with increased pressure are introduced from the inlet into the passage, and while continuously discharging the mixture, in the extruder, the raw materials conveyed along the outer surface of the screw body flow through the passage and then an outlet provided on the outer surface of the screw body A method for manufacturing a conductive composite material that guides the raw material to the conveying section, wherein the raw material contains a conductive filler and a thermoplastic elastomer, the rotational speed of the screw body is 200 rpm to 600 rpm, and the number of times the raw material passes through the passage until it is discharged as the mixed material is 4 times or more and 10 times or less. Claim 2 A method for manufacturing a conductive composite material according to claim 1, wherein the conveying section and the barrier section are alternately arranged in the axial direction from the base end to the tip end of the screw body, and among the conveying sections adjacent through the barrier section, the inlet is provided in the conveying section on the base end side and the outlet is provided in the conveying section on the tip end side, and the passage connecting the inlet and the outlet is provided across the barrier section. Claim 3 A method for manufacturing a conductive composite material according to claim 1, wherein the inlet, the outlet, and the passage are holes having a circular cross-sectional shape, and the inner diameter is 2 mm or more and 8 mm or less. Claim 4 A method for manufacturing a conductive composite material according to claim 1, wherein the raw material is conveyed from the base end of the screw body toward the tip end in the conveying section and flows from the base end of the screw body toward the tip end in the passage. Claim 5 A method for manufacturing a conductive composite material according to claim 1, wherein the conductive filler is a carbon nanotube and / or carbon black, and the thermoplastic elastomer is a hydrogenated styrene-butadiene-based thermoplastic elastomer. Claim 6 delete Claim 7 A method for manufacturing a conductive composite material according to claim 1, wherein the conductive filler contains carbon nanotubes, and the content of the carbon nanotubes in the conductive composite material is 0.75 to 3 weight percent. Claim 8 delete

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