JP6099716B2 - Kneading equipment - Google Patents

Description

  The present invention relates to a kneading apparatus for producing a thermoplastic resin molded body using a pressurized fluid.

  In recent years, various injection molding methods and extrusion molding methods using high-pressure carbon dioxide such as supercritical carbon dioxide have been studied. In such a molding method, since a very high-pressure fluid is introduced into the molten resin, molded articles having various functions can be manufactured. For example, in order to make incompatible polymers compatible with each other, an injection molding method or an extrusion molding method of a polymer alloy in which a molten resin and high-pressure carbon dioxide are contact-kneaded in a plasticizing cylinder has been proposed (Japanese Patent Laid-Open No. 2003). No. -94477 and Proc. Of the 17th Autumn Meeting of the Japan Society for Molding Technology, 227 (2009)). In these molding methods, the molten resin and high-pressure carbon dioxide are contact-kneaded by a kneading apparatus including a screw built in the plasticizing cylinder. Also, a molding method has been proposed in which supercritical carbon dioxide is introduced into a molten resin in the middle of an extruder having a vent portion in order to remove hardly volatile components from a thermoplastic resin (Japanese Patent Laid-Open No. 11-292921). ). Further, a molten resin of thermoplastic resin is injected and filled into the mold from the plasticizing cylinder, and then a pressurized fluid containing a functional material such as supercritical carbon dioxide and an organometallic complex is introduced into the mold. Thus, an injection molding method for manufacturing a thermoplastic resin molded body in which a functional material is dispersed on the surface has been proposed (Japanese Patent No. 3964447).

  By the way, the high-pressure carbon dioxide has a low solubility in the resin. Therefore, in the molding method having the step of bringing the molten resin and the pressurized fluid into contact with each other as described above, a large amount of high-pressure carbon dioxide and the molten resin are contact-kneaded. Difficult to do. Therefore, even when a functional material is used together with high-pressure carbon dioxide, it is difficult to introduce the functional material into the molten resin at a high concentration. From such a viewpoint, a kneading apparatus having an inlet for introducing a pressurized fluid into the upper side surface of the plasticizing cylinder and a vent port downstream of the inlet is used, and the molten resin and the high-pressure dioxide in the plasticizing cylinder are used. After contact kneading with a pressurized fluid containing carbon and a functional material, before injection filling into the mold, the resin internal pressure of the molten resin is reduced, and only the gasified carbon dioxide is separated from the molten resin, A method for producing a molded body in which carbon dioxide is exhausted from a vent port has been proposed (Japanese Patent Laid-Open No. 2009-299838). According to this molding method, it is possible to improve the concentration of the functional material introduced into the molten resin while controlling the concentration of high-pressure carbon dioxide in the molten resin.

  However, in a kneading apparatus such as that described in JP-A-2009-29888, a high-pressure kneading zone in which the molten resin and a pressurized fluid containing high-pressure carbon dioxide are contact-kneaded and the internal pressure of the molten resin is reduced. The decompression zone for separating the carbon dioxide gasified from the molten resin kneaded with the pressurized fluid is sealed by the molten resin itself. For this reason, even during contact kneading, carbon dioxide gasified from the high-pressure kneading zone is likely to be exhausted out of the plasticizing cylinder via the decompression zone, and the internal pressure of the resin in the high-pressure kneading zone tends to decrease. As a result, it becomes difficult to knead the molten resin and the pressurized fluid while maintaining a high pressure state, and high pressure carbon dioxide is easily vaporized from the pressurized fluid in the high pressure kneading zone during the contact kneading. is there.

  In view of the above, in a kneading apparatus including a plasticizing cylinder and a screw arranged to be able to rotate and advance / retreat in the plasticizing cylinder, the first resin kneading the molten resin and the pressurized fluid in the plasticizing cylinder. In order to separate the gas area into a second area where gasified carbon dioxide is exhausted, a through-hole penetrating the first area and the second area is formed in the screw, and a spring is provided in the through-hole. Has been proposed (Japanese Patent Laid-Open No. 2010-253703). According to such a kneading apparatus, when the pressure of the molten resin in the first area exceeds the pressing force of the spring, the poppet valve opens and the molten resin in the first area flows into the second area. The molten resin in any area in the cylinder can be maintained at a desired pressure.

  However, in the kneading apparatus having as a sealing mechanism a poppet valve that opens and closes by pressure control using a spring as described above, the molten resin does not pass through the poppet valve unless the resin internal pressure in the first area exceeds the spring pressure. Therefore, in the first area, the molten resin is subjected to flow resistance by the spring pressure even before the pressurized fluid is introduced. In consideration of the dispersibility of the pressurized fluid in the molten resin, it is desired to maintain a high pressure state as much as possible during contact kneading. Therefore, when the above kneading apparatus is used, the first area contains the pressurized fluid. Even when the pressure of the pressurized fluid is added to the pressure before introduction, it is necessary to use a poppet valve having a high spring pressure so that the poppet valve does not open during predetermined contact kneading. As a result, in the kneading apparatus, not only the plasticizing ability is reduced by the spring pressure at the time of plasticization, but also if the resin internal pressure of the molten resin in the first area does not exceed the high spring pressure even at the time of contact kneading, Since the area and the second area do not communicate with each other, the plasticizing ability tends to decrease. Therefore, when a resin having a high viscosity is used, the plasticization measurement tends to become unstable. Further, in the kneading apparatus, since the heated molten resin passes through the through-hole provided in the screw, the spring disposed in the through-hole is deteriorated by the heat of the molten resin by using a long-term molding machine, The spring constant is likely to change. As a result, it is difficult to keep the pressure in the high-pressure kneading zone constant over a long period of time, and there is a problem that molding cannot be performed stably in industrial production.

  The present invention has been made to solve the above-described problems. An object of the present invention is to introduce a pressurized fluid into a plasticizing cylinder, pressurize a molten resin obtained by plasticizing a thermoplastic resin in the plasticizing cylinder, and pressurize. When producing a thermoplastic resin molded body by contact-kneading with a fluid, the kneading apparatus has a high plasticizing ability and can stably produce a thermoplastic resin molded body over a long period of time, and the kneading apparatus Another object of the present invention is to provide a method for producing a thermoplastic resin molded body using the above-mentioned.

  One aspect of the present invention includes a plasticizing cylinder and a screw disposed in the plasticizing cylinder so as to be rotatable and movable back and forth, and a molten resin obtained by plasticizing a thermoplastic resin in the plasticizing cylinder; A kneading apparatus in which a high-pressure kneading zone for contact-kneading a pressurized fluid and an adjacent zone adjacent to the high-pressure zone is formed, and the rotational state of the screw is between the high-pressure kneading zone and the adjacent zone The high-pressure kneading zone and the adjacent zone are provided with a sealing mechanism that communicates with and shuts off, and the sealing mechanism is a mechanism that shuts off the high-pressure kneading zone and the adjacent zone according to the rotational state of the screw. A reduced-diameter portion of the screw having a seal portion, and a seal ring externally fitted to the reduced-diameter portion of the screw so as to be movable in the axial direction and having a contact surface in contact with the seal portion. When the seal portion of the reduced diameter portion and the contact surface of the seal ring are separated according to the rotation state of the screw, the high pressure kneading zone and the adjacent zone communicate with each other, and the seal of the reduced diameter portion When the part and the contact surface of the seal ring come into contact with each other, the high-pressure kneading zone and the adjacent zone are blocked.

  Another aspect of the present invention is the kneading apparatus described above, wherein the screw includes a locking portion, and the seal ring engages and disengages with the locking portion of the screw. When the screw is reversely rotated at a predetermined rotational speed or more, the screw locking portion and the seal ring locked portion are engaged with each other, and the screw and the seal ring are provided. , The contact state between the seal portion of the reduced diameter portion and the contact surface of the seal ring is maintained.

  The objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description and the accompanying drawings.

FIG. 1 is a schematic cross-sectional view of an essential part showing an example of a kneading apparatus according to an embodiment of the present invention, showing a state where a high-pressure kneading zone and a depressurization zone are in communication. FIG. 2 is a schematic cross-sectional view showing a main part of an example of the kneading apparatus according to the embodiment of the present invention, and shows a state where the high-pressure kneading zone and the decompression zone are blocked. FIG. 3 is a schematic perspective view showing an example of a sealing mechanism of the kneading apparatus according to the embodiment of the present invention. FIG. 4 is a main part schematic enlarged cross-sectional view showing an example of the sealing mechanism of the kneading apparatus according to the embodiment of the present invention. FIG. 5 is a main part schematic enlarged cross-sectional view showing another example of the sealing mechanism of the kneading apparatus according to the embodiment of the present invention. FIG. 6 is a schematic cross-sectional view showing an example of a molding machine according to the embodiment of the present invention.

  Hereinafter, a kneading apparatus according to an embodiment of the present invention and a method for producing a thermoplastic resin molded body using the kneading apparatus will be described with reference to the drawings.

  1 and 2 are schematic cross-sectional views of the main part showing an example of a kneading apparatus according to an embodiment of the present invention. FIG. 1 shows a state in which a high-pressure kneading zone and a reduced-pressure zone communicate with each other. Indicates a state where the high-pressure kneading zone and the decompression zone are blocked. FIG. 3 is a schematic perspective view showing the sealing mechanism in FIGS. 1 and 2.

  The kneading apparatus 200 includes a plasticizing cylinder 210 and a screw 20 disposed in the plasticizing cylinder 210 so as to be rotatable and advanceable / retractable. Further, although not shown in the drawing, at the rear end portion on the upstream side of the plasticizing cylinder 210, a rotation driving means such as a rotation motor for rotating the screw 20, a ball screw for moving the screw 20 forward and backward, a motor for driving the same, and the like And a nozzle portion for injecting molten resin is connected to the downstream end portion. As shown in FIG. 1 and FIG. 2, the kneading apparatus 200 of the present embodiment has a screw 20 that is not bent when viewed from the rear side of the plasticizing cylinder 210, as in the configuration of a conventionally known kneading apparatus. When it is rotated clockwise, the resin is forwardly rotated forward (nozzle side), and when it is rotated clockwise, it is reversely rotated.

  A plastic supply port 201 for supplying a thermoplastic resin to the plasticizing cylinder 210 and a pressurized fluid containing high-pressure carbon dioxide are introduced into the plasticizing cylinder 210 in order from the upstream side on the upper side surface of the plasticizing cylinder 210. For this purpose, there are formed an inlet port 202 and a vent port 203 for exhausting gasified carbon dioxide from the plasticizing cylinder 210. As will be described later, a resin supply hopper 211 and an introduction valve 212 are disposed in the resin supply port 201 and the introduction port 202, respectively, and the vent port 203 is evacuated via a buffer container 219. A pump 220 is connected. In addition, a band heater (not shown) is disposed on the outer wall surface of the plasticizing cylinder 210, whereby the plasticizing cylinder 210 is heated to plasticize the thermoplastic resin. Further, a pressure gauge and a temperature sensor (not shown) are provided at a position facing the introduction port 202 and a position facing the vent port 203 on the lower side surface of the plasticizing cylinder 210, respectively.

  Therefore, in the kneading apparatus 200 of the present embodiment, when the screw 20 is rotated forward, thermoplastic resin is supplied from the resin supply port 201 into the plasticizing cylinder 210, and the thermoplastic resin is plasticized by the band heater. It becomes molten resin and is sent forward. The molten resin sent to the vicinity of the introduction port 202 is contact-kneaded with the introduced pressurized fluid under high pressure. Next, by reducing the internal pressure of the molten resin that has been contact-kneaded with the pressurized fluid, the gasified carbon dioxide is separated from the molten resin, and the gasified carbon dioxide is exhausted from the vent port 203. The molten resin sent further forward is pushed out to the tip of the screw 20, and the pressure of the molten resin becomes a reaction force against the screw 20, and the screw 20 moves backward by the reaction force to perform measurement. Thereby, in the plasticizing cylinder 210, in order from the upstream side, the plasticizing zone 21 that plasticizes the thermoplastic resin into the molten resin, the molten resin and the pressurized fluid introduced from the inlet 202 are brought into contact under high pressure. A high pressure kneading zone 22 for kneading and a pressure reducing zone 23 for exhausting carbon dioxide separated from the molten resin from the vent port 203 are formed by lowering the internal pressure of the molten resin kneaded in contact with the pressurized fluid. In order to efficiently perform contact kneading between the molten resin and the pressurized fluid, a plurality of introduction ports 202 and vent ports 203 are provided in the plasticizing cylinder 210, and the high pressure kneading zone 22 and the decompression zone 23 are provided in the plasticizing cylinder 210. A plurality of each may be formed.

  As shown in FIGS. 1 and 2, the zones 21, 22, and 23 are communicated and blocked between the plasticizing zone 21, the high-pressure kneading zone 22, and the decompression zone 23 according to the rotational state of the screw 20. An upstream seal mechanism S1 and a downstream seal mechanism S2 are disposed. Thereby, when the pressurized fluid is introduced into the high-pressure kneading zone 22, the upstream side and the downstream side of the high-pressure kneading zone 22 are mechanically sealed according to the rotation state of the screw 20, so The adjacent zones 21 and 23 can be blocked. In addition, according to the sealing mechanisms S1 and S2 of the present embodiment, the high pressure kneading zone 22 and the adjacent zones 21 and 23 can be communicated and blocked according to the rotational state of the screw 20 without depending on the pressure control. Low flow resistance of resin. Furthermore, since the high-pressure kneading zone 22 can be sealed from the adjacent zones 21 and 23 according to the rotational state of the screw 20, the pressure in the high-pressure kneading zone 22 can be maintained at an arbitrary timing. Therefore, even when a resin having a high viscosity is contact-kneaded, a high plasticizing ability can be maintained. And if mechanical seal mechanism S1, S2 which exhibits sealing performance according to the rotation state of such a screw 20 is used, even if high temperature molten resin passes sealing mechanism S1, S2, degradation of sealing performance will be carried out. Therefore, even after the molding machine is operated for a long period of time, there is little change in the pressure of the high-pressure kneading zone 22, and therefore a thermoplastic resin molded body can be produced stably over a long period of time. Further, since these sealing mechanisms S1 and S2 communicate and block the high-pressure kneading zone 22 and the adjacent zones 21 and 23 according to the rotational state of the screw 20, for example, forward rotation and reverse rotation of the screw 20 can be performed arbitrarily. If it is performed at the timing, the internal pressure of the molten resin contact-kneaded with the pressurized fluid can be reduced in a state where the molten resin is retained in the high-pressure kneading zone 22, and the gasified carbon dioxide can be separated from the molten resin. . As a result, the molten resin having a low concentration of high-pressure carbon dioxide and the pressurized fluid can be repeatedly contact-kneaded without sending the molten resin forward. In addition, when a pressurized fluid containing a functional material is used, a molded body in which the functional material is dispersed at a high concentration can be manufactured.

  In the kneading apparatus 200 according to the present embodiment, the seal mechanism that communicates and blocks the high-pressure kneading zone 22 and the other adjacent zones 21 and 23 according to the rotational state of the screw 20 is at least downstream of the high-pressure kneading zone 22. It is preferable to be provided at both the upstream side and the downstream side of the high-pressure kneading zone 22. That is, as understood from FIGS. 1 and 2, the introduction of the pressurized fluid into the high-pressure kneading zone 22 causes the high-pressure pressurized fluid to flow into the plasticizing zone 21 and the high-pressure kneading upstream of the high-pressure kneading zone 22. On the downstream side of the high-pressure kneading zone 22, the pressurized fluid and the molten resin flowing from the upstream side are connected to the high-pressure kneading zone 22 and the decompression zone 23. Acts on the downstream seal mechanism S2 so as to communicate with each other. Moreover, since the molten resin is usually filled in the upstream side of the high-pressure kneading zone 22, the pressurized fluid hardly leaks. Therefore, a simple sealing mechanism such as a backflow prevention valve having a low spring pressure is disposed upstream of the high-pressure kneading zone 22, and at least downstream of the high-pressure kneading zone 22 according to the rotational state of the screw 20. If the downstream side seal mechanism S2 that communicates and blocks the pressure reduction zone 23 and the pressure reduction zone 23 is provided, the high pressure kneading zone 22 and the pressure reduction zone 23, which are likely to deteriorate the sealing performance, can be reliably blocked, and the high pressure kneading zone 22 during contact kneading The high pressure state can be maintained. In this embodiment, since the upstream side seal mechanism S1 and the downstream side seal mechanism S2 have basically the same configuration, the downstream side seal mechanism S2 will be mainly described below.

  As shown in FIGS. 1 to 3, the screw 20 of the present embodiment has a reduced diameter portion that is reduced in diameter in the boundary region between the high-pressure kneading zone 22 and the decompression zone 23 as compared with the region adjacent to the boundary region. 50. Further, a downstream seal ring 60 is externally fitted to the reduced diameter portion 50 in a loosely fitted state so as to be movable in the axial direction (front-rear direction) within the range of the reduced diameter portion 50. The reduced diameter portion 50 and the downstream seal ring 60 constitute a downstream seal mechanism S2. In order to externally fit the upstream and downstream seal rings 40 and 60 to the reduced diameter portions 30 and 50, the screw 20 includes, in order from the upstream side, the first screw portion 20a, the second screw portion 20b, and the third screw portion. The screw part 20c is divided into parts, and these are reduced diameter parts 30 and 50 by screws not shown.

  The reduced diameter portion 50 disposed between the high-pressure kneading zone 22 and the decompression zone 23 is connected to the upstream second screw portion 20b and has a truncated cone portion (seal portion) having a tapered surface inclined forward. 51 and a cylindrical portion 52 having a horizontal plane that is connected from the truncated cone portion 51 and extends horizontally in the axial direction. Further, on the end surface 54 of the downstream third screw portion 20c, a plurality of protrusions 54a are formed at predetermined intervals in the circumferential direction as locking portions for preventing the downstream seal ring 60 from rotating. The structure of the reduced diameter portion 50 is not particularly limited as long as it can communicate and block the high-pressure kneading zone 22 and the decompression zone 23. For example, the reduced diameter portion 50 may have a structure in which cylindrical portions having different diameters are connected, or may have a structure in which the truncated cone portion 51 is disposed on the downstream side.

  As shown in FIG. 3, the downstream seal ring 60 has a through hole 61 so as to externally fit the reduced diameter portion 50 of the screw 20. As shown in FIGS. 1 and 2, the through-hole 61 has a tapered portion 62 having a tapered surface (contact surface) whose diameter decreases toward the front on the upstream side, and forward from the tapered portion 62. An annular portion 63 that extends horizontally is connected to each other. The tapered surface of the tapered portion 62 is formed so as to abut on at least a part of the tapered surface of the truncated cone portion 51 in a close contact state. The structure of the through hole 61 is not particularly limited as long as it can communicate and block the high pressure kneading zone 22 and the decompression zone 23. For example, the through hole 61 may have a structure in which a plurality of annular portions having different inner diameters are formed, or may have a structure in which the tapered portion 62 is disposed on the downstream side. Furthermore, the inner diameter of the annular portion 63 of the through hole 61 is larger than the diameter of the cylindrical portion 52 of the reduced diameter portion 50 so that the downstream seal ring 60 can move in the axial direction within the range of the reduced diameter portion 50 of the screw 20. Largely formed. The downstream ring surface 66 of the downstream seal ring 60 is provided with a plurality of notches 67 in the circumferential direction, which are inclined so as to be deep in the clockwise direction when viewed from the downstream side, as locked portions. ing. Thereby, the downstream seal ring 60 moves in the axial direction within the depth range of the notch 67 with respect to the screw 20 according to the rotational state of the screw 20, and when the protrusion 54 a is engaged with the notch 67, Further axial movement of the downstream seal ring 60 with respect to the screw 20 is restricted.

  Therefore, when the downstream seal ring 60 moves downstream with respect to the screw 20, the tapered surface of the truncated cone part 51 and the tapered surface of the tapered part 62 are separated from each other, and a runway for molten resin and high-pressure carbon dioxide is formed. The gap G opens between the inner peripheral surface of the downstream seal ring 60 and the outer peripheral surface of the reduced diameter portion 50 of the screw 20. On the other hand, when the downstream seal ring 60 moves upstream with respect to the screw 20, the tapered surface of the truncated cone portion 51 and the tapered surface of the tapered portion 62 come into contact with each other, and the inner peripheral surface of the downstream seal ring 60 and the screw are in contact with each other. The gap G between the 20 outer diameter surfaces of the reduced diameter portion 50 is closed. Then, when the downstream seal ring 60 moves to the upstream side and the protrusion 54a and the notch 67 engage with each other, the movement of the downstream seal ring 60 is restricted. Rotate together. Thereby, the contact state of the taper surface of the truncated cone part 51 and the taper surface of the taper part 62 is maintained during contact kneading, and the high-pressure kneading zone 22 can be reliably sealed. However, when the plasticizing zone 21 and the high pressure kneading zone 22 and the high pressure kneading zone 22 and the decompression zone 23 communicate with each other, the tapered surfaces of the truncated cone portions 31 and 51 and the tapered surfaces of the tapered portions 42 and 62 are separated from each other. Thus, molten resin or further pressurized fluid enters the gap G from the upstream side. Therefore, when the upstream and downstream seal rings 40 and 60 move to the downstream side, the tapered surfaces of the truncated cone portions 31 and 51 can be obtained even if the upstream and downstream seal rings 40 and 60 do not rotate with the screw 20. Therefore, the high pressure kneading zone 22 and the adjacent zones 21 and 23 can be maintained in communication with each other. The locking portion and the locked portion provided on the screw 20 and the upstream side and downstream side seal rings 40, 60 respectively rotate the upstream side and downstream side seal rings 40, 60 when they are engaged. Any structure can be adopted as long as it can rotate together with the screw 20 in the stopped state. For example, a pin may be used as the locking portion or the locked portion. Further, the locking portion may be provided on the downstream side of the second screw portion 20 b and the non-locking portion may be provided on the upstream side of the downstream seal ring 60 in accordance with the structure of the truncated cone portion 51 and the tapered portion 62.

  A metal outer seal member 70 is fitted on the outer peripheral surface of the downstream seal ring 60 so as to protrude from the outer peripheral surface of the downstream seal ring 60. Thereby, the sealing performance between the downstream seal ring 60 and the plasticizing cylinder 210 is ensured. A resin outer seal member may be used. Further, in the downstream seal ring 60 of the present embodiment, as shown in FIG. 4, the outer ring surface 64 has an outer diameter that is larger than the diameter of the second upstream screw portion 20 b facing each other. Therefore, when the high-pressure kneading zone 22 and the decompression zone 23 are shut off, the downstream seal ring 60 is arranged in a mode in which it slightly protrudes in the radial direction from the second screw portion 20b on the upstream side. However, as shown in FIG. 5, the outer diameter of the upstream ring surface 64 may be formed to be substantially the same as or smaller than the diameter of the opposing second screw portion 20b. That is, since a high-pressure pressurized fluid is introduced from the introduction port 202 in the high-pressure kneading zone 22, if the outer diameter of the upstream ring surface 64 is larger than the diameter of the second upstream screw portion 20 b facing each other, the screw 20. The upstream ring surface 64 protruding from the front is pushed forward by the pressure of the pressurized fluid, thereby immediately stopping the rotation of the screw 20 or reducing the rotational speed of the reverse rotation without causing the screw 20 to rotate forward. The high pressure kneading zone 22 and the decompression zone 23 can be communicated with each other. On the other hand, if the outer diameter of the upstream ring surface 64 is substantially the same as or smaller than the diameter of the opposing second screw portion 20b, the pressure by the pressurized fluid is not applied to the upstream ring surface 64, so contact kneading. Sometimes, the high-pressure kneading zone 22 and the decompression zone 23 can be shut off more reliably.

  The structure of the upstream side seal mechanism S1 is the same as that of the downstream side seal mechanism S2, and a truncated cone portion is provided between the plasticizing zone 21 and the high-pressure kneading zone 22 as shown in FIGS. A reduced diameter portion 30 having a (seal portion) 31 is disposed, and a protruding portion 34a is provided on the upstream end surface 34 of the second screw portion 20b. Further, the upstream-side seal ring 40 is externally fitted to the reduced diameter portion 30 in a loosely fit state so as to be movable in the axial direction (front-rear direction) within the range of the reduced diameter portion 30. Furthermore, a tapered portion 42 having a tapered surface (contact surface) and an annular portion 43 having a diameter larger than the diameter of the cylindrical portion 32 are formed in the through hole of the upstream seal ring 40. And the notch 47 which engages with the projection part 34a provided in the end surface 34 of the 2nd screw part 20b is formed in the circumferential direction in the downstream ring surface 46 of the upstream seal ring 40 at multiple places. Thus, similarly to the downstream seal mechanism S2, when the upstream seal ring 40 moves downstream with respect to the screw 20, the tapered surface of the truncated cone portion 31 and the tapered surface of the tapered portion 42 are separated from each other, and A gap G between the inner peripheral surface of the side seal ring 40 and the outer peripheral surface of the reduced diameter portion 30 is opened. On the other hand, when the upstream seal ring 40 moves upstream with respect to the screw 20, the tapered surface of the truncated cone portion 31 and the tapered surface of the tapered portion 42 come into contact with each other, and the inner peripheral surface of the upstream seal ring 40 is contracted. A gap G between the outer peripheral surface of the diameter portion 30 is closed. When the protrusion 34 a is engaged with the notch 47, the upstream seal ring 40 rotates with the screw 20.

  Next, the operation of the sealing mechanisms S1 and S2 will be described according to the steps performed in the kneading apparatus 200. As shown in FIG. 1, when the screw 20 is rotated forward (counterclockwise), the upstream and downstream seal rings 40 and 60 move to the downstream side of the reduced diameter portions 30 and 50, respectively. Thereby, the taper surface of the truncated cone part 31 and the taper surface of the taper part 42 are separated from each other, and a gap G between the inner peripheral surface of the upstream seal ring 40 and the outer peripheral surface of the reduced diameter part 30 of the screw 20 is formed. The plasticizing zone 21 and the high-pressure kneading zone 22 communicate with each other. When the protrusion 34 a and the notch 47 are engaged, the upstream seal ring 40 rotates together with the screw 20. Thereby, since the communication state of the plasticization zone 21 and the high pressure kneading zone 22 is maintained, the molten resin can be smoothly fed from the plasticizing zone 21 to the high pressure kneading zone 22.

  When a certain amount of the molten resin is sent to the high-pressure kneading zone 22, as shown in FIG. Then, the upstream and downstream seal rings 40 and 60 move upstream as the screw 20 rotates in reverse, so that the tapered surfaces of the truncated cone portions 31 and 51 abut against the tapered surfaces of the tapered portions 42 and 62. The gap G formed between the inner peripheral surface of the upstream and downstream seal rings 40, 60 and the outer peripheral surface of the reduced diameter portions 30, 50 is closed. When the protrusions 34a and 54a of the screw 20 engage with the notches 47 and 67 of the upstream and downstream seal rings 40 and 60, the upstream and downstream seal rings 40 and 60 rotate together with the screw 20. To do. As a result, the high-pressure kneading zone 22 and the decompression zone 23 are maintained in a shut-off state. Therefore, the molten resin and the pressurized fluid can be contact-kneaded under high pressure.

  When the high-pressure kneading zone 22 and the adjacent zones 21 and 23 are sealed by the upstream and downstream sealing mechanisms S1 and S2, and the molten resin is contact-kneaded with the pressurized fluid, the internal pressure of the molten resin is then lowered. Therefore, the screw 20 is again rotated forward by the rotation driving means. Then, the protrusions 34a and 54a and the notches 47 and 67 are engaged and disengaged, and the upstream and downstream seal rings 40 and 60 move downstream as the screw 20 rotates forward. The taper surface 51 and the taper surfaces 42 and 62 are separated from each other, and a gap G between the inner peripheral surface of the upstream and downstream seal rings 40 and 60 and the outer peripheral surface of the reduced diameter portions 30 and 50 is opened. To do. As a result, the high pressure kneading zone 22 and the decompression zone 23 communicate with each other, and the resin internal pressure of the molten resin decreases, so that the carbon dioxide gasified from the molten resin is separated from the vent port 203 provided in the decompression zone 23. Gasified carbon dioxide can be exhausted. As described above, after the molten resin and the pressurized fluid are contact-kneaded in the high-pressure kneading zone 22, the downstream seal ring 60 receives the pressure of the molten resin and the pressurized fluid. The high-pressure kneading zone 22 and the pressure-reducing zone 23 can be communicated also by stopping the rotation or decreasing the rotational speed of the screw 20 in the reverse rotation.

  Next, a method for producing a thermoplastic resin molded body using the kneading apparatus 200 of the present embodiment will be specifically described.

  In the method for producing a thermoplastic resin molded body of the present embodiment, the thermoplastic resin is supplied to the plasticizing cylinder 210 and the screw 20 is rotated, so that the thermoplastic resin is plasticized in the plasticizing zone 21 to be a molten resin. The plasticizing process is first performed.

  As the thermoplastic resin, various resins can be used depending on the type of the target resin molding. Specifically, for example, heat of polypropylene, polymethyl methacrylate, polyamide, polycarbonate, amorphous polyolefin, polyether imide, polyethylene terephthalate, polyether ether ketone, ABS resin, polyphenylene sulfide, polyamide imide, polylactic acid, polycaprolactone, etc. Plastic resins and composite materials thereof can be used. Moreover, what knead | mixed various inorganic fillers, such as glass fiber, a talc, and a carbon fiber, can also be used for these thermoplastic resins.

  Next, in the high-pressure kneading zone 22, a kneading process is performed in which the molten resin and the pressurized fluid containing high-pressure carbon dioxide are contact-kneaded. In the kneading apparatus 200 of the present embodiment, the molten resin and the pressurized fluid are contact-kneaded in a state where the high-pressure kneading zone 22 and the adjacent zones 21 and 23 are blocked by the upstream and downstream sealing mechanisms S1 and S2. Therefore, leakage of the pressurized fluid from the high-pressure kneading zone 22 is suppressed, and the pressurized fluid can be introduced into the molten resin while maintaining the high-pressure state. The pressure and temperature of the high-pressure kneading zone 22 at the time of contact kneading can be appropriately selected within the range in which the pressurized fluid is well dispersed in the molten resin, depending on the type of thermoplastic resin and pressurized fluid used. .

As high-pressure carbon dioxide, high-pressure carbon dioxide in a liquid state, a gas state, or a supercritical state can be used. These high-pressure carbon dioxide functions as a plasticizer, a solvent, or a compatibilizing agent that is harmless to the human body, has excellent diffusibility to the molten resin, and can be easily removed from the molten resin. The pressure and temperature of the high-pressure carbon dioxide can be appropriately selected according to the purpose. For example, when high-pressure carbon dioxide is used as a plasticizer or a compatibilizing agent, one having a pressure of 3 to 5 MPa at which the high-pressure carbon dioxide has a low density can be used. Moreover, when utilizing a functional material, in order to raise the density | concentration of the functional material in a pressurized fluid, the high pressure carbon dioxide which has a high density is used preferably. For example, when a functional material is used, the pressure is 4 MPa or more, preferably 5 to 25 MPa, the temperature is 0 ° C. or more, preferably 5 to 100 ° C., and high-pressure carbon dioxide having a density of 0.6 g / cm ³ or more. Preferably used.

  The pressurized fluid may contain a functional material. Any functional material can be used without particular limitation as long as it can be dispersed in high-pressure carbon dioxide and can give the desired function to the obtained molded body. Specific examples of such functional materials include compatibilizers, surfactants, organometallic complexes, metal alkoxides, dyes, and nanocarbons for promoting the alloying of various resins. In addition, high pressure carbon dioxide itself functions as a plasticizer for the molten resin even at a low pressure, but various solvents such as alcohol and plasticizers may be used to promote the plasticizing effect. When using a functional material, the concentration of the functional material in the pressurized fluid can be appropriately selected in consideration of the type of the functional material to be used and the function of the target molded body, and is not particularly limited. Considering the permeability to the molten resin and the aggregation of the functional material in the pressurized fluid, the saturation concentration is preferred.

  The pressurized fluid may further contain a solvent. For example, by using water together with high-pressure carbon dioxide and a water-soluble surfactant, a pressurized fluid obtained as an emulsion (emulsion) can be used. Since materials that dissolve in high-pressure carbon dioxide are limited, by using such a solvent, water-soluble materials can be introduced into the molten resin using the diffusibility and compatibility of carbon dioxide with the resin. Can do. In addition, if only water is kneaded with the molten resin, water may remain in the molded body, which may cause adverse effects such as hydrolysis.However, when water is introduced into the molten resin as an emulsion with high-pressure carbon dioxide, the carbon dioxide is rapidly absorbed. Water together with carbon can be separated from the molten resin, and the above adverse effects can be prevented. Furthermore, when a functional material is used, the pressurized fluid may contain a solvent that dissolves the functional material. For example, when using an organometallic complex, a fluorine-based organic solvent such as perfluoropentylamine may be used to increase the concentration of the organometallic complex in the pressurized fluid.

  A method for preparing a pressurized fluid containing high-pressure carbon dioxide is not particularly limited, and a conventionally known method can be used. For example, a pressurized fluid can be prepared by pressurizing liquid carbon dioxide with a pressurizing means such as a syringe pump. Moreover, when preparing the pressurized fluid containing a high pressure carbon dioxide and a functional material, a pressurized fluid can be prepared by mixing and stirring high pressure carbon dioxide and a functional material. Furthermore, when using a solution in which a functional material is dissolved in a solvent, a pressurized fluid can be prepared by mixing high-pressure carbon dioxide and a solution pressurized to a predetermined pressure by a pressurizing means.

  Any method can be used as a method for introducing the pressurized fluid into the high-pressure kneading zone 22. For example, the pressurized fluid may be introduced intermittently into the high-pressure kneading zone 22 or may be introduced continuously. In addition, the introduction of the pressurized fluid is preferably controlled by using a syringe pump capable of stable liquid feeding. When a pressurized fluid is introduced using a syringe pump, high-pressure carbon dioxide in a liquid state that is stable even at high density is preferably used.

  Next, a separation step is performed in which the high pressure kneading zone 22 and the decompression zone 23 communicate with each other and the internal pressure of the molten resin that has been kneaded in contact with the pressurized fluid is reduced to separate the gasified carbon dioxide from the molten resin. Is called. In the present embodiment, since the seal mechanism S2 that communicates the high-pressure kneading zone 22 and the decompression zone 23 in accordance with the rotational state of the screw 20 is used, it does not depend on the pressure in the high-pressure kneading zone 22 and quickly melts. The high-pressure carbon dioxide in the pressurized fluid introduced into the resin can be gasified, and the gasified carbon dioxide can be exhausted out of the plasticizing cylinder 210. If the pressure in the decompression zone 23 is lower than the pressure in the high-pressure kneading zone 22, the internal pressure of the resin is reduced, so that it is not particularly limited. A vacuum pump may be used to efficiently exhaust the gasified carbon dioxide.

  Further, when separating the gasified carbon dioxide from the molten resin, the carbon dioxide may be separated while sending the molten resin to the decompression zone 23, or in a state where the molten resin is retained in the high pressure kneading zone 22. Carbon may be separated. That is, in the kneading apparatus 200 according to the present embodiment, the downstream sealing mechanism S2 that connects and blocks the high-pressure kneading zone 22 and the pressure-reducing zone 23 according to the rotational state of the screw 20 is provided. Even if the high pressure kneading zone 22 and the decompression zone 23 are communicated with each other even if they are not sent to the zone 23, the resin internal pressure of the molten resin can be lowered while the molten resin is retained in the high pressure kneading zone 22, thereby Part of the high-pressure carbon dioxide in the high-pressure kneading zone 22 is gasified, and the gasified carbon dioxide can be exhausted from the decompression zone 23. For example, by rotating the screw 20 in the reverse direction and controlling the number of rotations of the screw 20 in a state in which the molten resin is not sent forward, the taper surface of the truncated cone part 51 and the taper surface of the taper part 62 are separated from each other. What is necessary is just to open G slightly. Thereby, the pressurized fluid can be again brought into contact with the molten resin in the high-pressure kneading zone 22 in which the concentration of high-pressure carbon dioxide is lowered, and the pressurized fluid can be further introduced into the molten resin. Moreover, when the pressure in the high-pressure kneading zone 22 is higher than the internal pressure of the resin in the plasticizing zone 21, the upstream side seal mechanism S1 is likely to move in a direction to shut off the plasticizing zone 21 and the high-pressure kneading zone 22. The flow of new molten resin from the zone 21 to the high-pressure kneading zone 22 is suppressed, and leakage of the pressurized fluid to the plasticizing zone 21 can be prevented. Therefore, according to the manufacturing method using the kneading apparatus 200 of the present embodiment, the kneading step and the separation step can be repeatedly performed while the molten resin is retained in the high-pressure kneading zone 22. Thus, for example, when a pressurized fluid containing a functional material is used, a thermoplastic resin molded body in which the functional material is dispersed at a high concentration is obtained even if the functional material has low solubility in high-pressure carbon dioxide. be able to. At this time, as described above, in order to repeat the communication and blocking between the high-pressure kneading zone 22 and the decompression zone 23, the forward rotation and reverse rotation of the screw 20 may be repeated in small increments, or the predetermined rotation of the screw 20 The reverse rotation of several or more and the stop of the rotation of the screw 20 or the decrease of the reverse rotation of the screw 20 may be repeated in small increments.

  When the gasified carbon dioxide is separated from the molten resin, the molten resin is sent to the tip of the screw 20. And the shaping | molding process which shape | molds the molten resin inject | emitted from the front-end | tip part of the plasticizing cylinder 210 in a desired shape is performed. As the molding step used in the present embodiment, a conventionally known injection molding method or extrusion molding method can be used according to the type of the target molded body. When the injection molding method is used, after the plasticizing measurement is completed, the screw 20 is advanced by moving means connected to the rear end portion of the plasticizing cylinder 210, and the molten resin is put into a mold having a predetermined internal shape. A thermoplastic resin molding can be produced by injection filling. In addition, when using the extrusion molding method, a molded body having a shape such as a pellet shape, a tube shape, or a sheet shape is manufactured by injecting a molten resin from the plasticizing cylinder 210 to an extrusion die having a predetermined internal shape. can do.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example, this invention is not limited to these Examples.

Example 1
In the present embodiment, a thermoplastic resin molded body in which a functional material is dispersed is obtained by injection molding using a kneading apparatus 200 having a sealing mechanism having the form of FIG. 4 as the upstream and downstream sealing mechanisms S1, S2. Manufactured. Nylon 6 (Toray, Amilan CM1011G30) added with 30% by mass of glass fiber is used as the thermoplastic resin, hexafluoroacetylacetona palladium (II), which is an organometallic complex, is used as the functional material, and par Fluoropentylamine was used. The introduction amount was adjusted so that the concentration of carbon dioxide was about 2% by mass and the concentration of the organometallic complex was about 100 ppm with respect to the mass of the molten resin for each shot.

  FIG. 6 is a schematic cross-sectional view showing the molding machine used in this example. As shown in FIG. 6, this molding machine 1000 prepares a pressurized fluid by mixing high-pressure carbon dioxide and a solution C in which an organometallic complex is dissolved in a fluorinated organic solvent, and the prepared pressurized fluid. Is provided with the pressurized fluid supply device 100 that supplies the plasticizing cylinder 210, the kneading device 200 described above, and the injection molding device 250 having a mold. Operation of the pressurized fluid supply device 100, the kneading device 200, and the injection molding device 250 is controlled by a control device (not shown).

  The pressurized fluid supply apparatus 100 includes a liquid carbon dioxide cylinder 101, a carbon dioxide syringe pump 102 for supplying high-pressure carbon dioxide by pressurizing the liquid carbon dioxide to a predetermined pressure, and an organometallic complex dissolved in a solvent. A solution tank 111 for preparing the solution C and a solution syringe pump 112 for pressurizing and feeding the solution C to a predetermined pressure are provided. The piping connecting the liquid carbon dioxide cylinder 101 and the carbon dioxide syringe pump 102 and the piping connecting the carbon dioxide syringe pump 102 and the plasticizing cylinder 210 are respectively the suction air operated valve 104 and the supply air operated valve. 105 is arranged. In addition, a suction air operated valve 114 and a supply air operated valve 115 are connected to a pipe connecting the solution tank 111 and the solution syringe pump 112 and a pipe connecting the solution syringe pump 112 and the plasticizing cylinder 210, respectively. It is arranged.

  When preparing a pressurized fluid, first, the suction air operated valve 104 is opened, and liquid carbon dioxide is sucked from the liquid carbon dioxide cylinder 101. Next, liquid carbon dioxide is pressurized to a predetermined pressure by pressure control of the carbon dioxide syringe pump 102. In this example, high-pressure carbon dioxide having a pressure of 10 MPa and a temperature of 10 ° C. was supplied.

  On the other hand, the suction air operated valve 114 on the solution syringe pump 112 side is opened, and the solution C in which the organometallic complex is dissolved in the solvent is sucked from the solution tank 111 through the filter 113 at room temperature, and the solution syringe pump The solution C is pressurized to a predetermined pressure by the pressure control of 112. In this example, the solution C was pressurized to 10 MPa.

  Next, after the supply air operated valves 105 and 115 are opened, the carbon dioxide syringe pump 102 and the solution syringe pump 112 are switched from the pressure control to the flow rate control, and the high pressure carbon dioxide and the pressurized solution C are supplied with a predetermined amount. It is made to flow so that it may become a flow ratio. Thereby, the high pressure carbon dioxide and the solution C are mixed in the pipe. In this example, the supply volume ratio between the high-pressure carbon dioxide and the solution C was set to 5: 1. If a pressurized fluid having a volume ratio of high-pressure carbon dioxide to solution C in a certain range (1: 1 to 10: 1) is used, thermal decomposition of the organometallic complex can be prevented by high-pressure carbon dioxide in the kneading step, and High-pressure carbon dioxide can function as a compatibilizing agent that assists the dispersion of the organometallic complex in the molten resin.

  On the other hand, in the kneading apparatus 200, the thermoplastic resin supplied from the resin supply hopper 211 heats the plasticizing cylinder 210 with a band heater (not shown) provided on the outer wall surface of the plasticizing cylinder 210, and the screw 20. Are kneaded and melted by rotating them forward. In this example, the plasticizing cylinder 210 was heated so that the resin temperature was 210 to 240 ° C.

  When the molten resin is sent to the high-pressure kneading zone 22, the screw 20 is positioned 20 mm before the plasticizing and metering completion position (die side position) to shut off the high-pressure kneading zone 22, the decompression zone 23, and the plasticizing zone 21. Then, the screw 20 was rotated in the reverse direction (rotation speed: 50 rpm). As a result, the upstream and downstream seal rings 40, 60 are moved upstream to bring the tapered surfaces of the truncated cone parts 31, 51 into contact with the tapered surfaces of the tapered parts 42, 62, and further upstream and downstream. By rotating the side seal rings 40, 60 together with the screw 20, the gap G between the inner peripheral surface of the upstream and downstream seal rings 40, 60 and the outer peripheral surface of the screw 20 is closed, and the high-pressure kneading zone 22 is closed. And the decompression zone 23 and the plasticizing zone 21 were shut off.

  As shown in FIG. 6, an introduction valve 212 for introducing a pressurized fluid is provided at the introduction port 202 of the plasticizing cylinder 210. The introduction valve 212 has a fluid supply port 218 at the base end connected to the introduction port 202 of the plasticizing cylinder 210 and an introduction piston 217 inside. Therefore, the pressurized fluid is introduced from the pressurized fluid supply device 100 to the plasticizing cylinder 210 by opening the fluid supply port 218 with the introduction piston 217. In this embodiment, after the high-pressure kneading zone 22 is sealed by the upstream and downstream sealing mechanisms S1, S2, the shot is intermittently shot by shot by flow control so that the pressurized fluid stays in the high-pressure kneading zone 22 for 1 second. A pressurized fluid was introduced, and the molten resin and the pressurized fluid were contact-kneaded. The resin internal pressure before introduction of the pressurized fluid was 0.1 MPa, and the resin internal pressure at the time of contact kneading after introduction of the pressurized fluid was 1 to 8 MPa. In addition, when molding is performed under the same plasticization metering conditions using a conventional kneading device provided with a poppet valve that opens and closes by spring pressure in the screw, the internal pressure of the resin before introduction of the pressurized fluid is 8 MPa. The internal pressure of the resin was 13-14 MPa. Therefore, it was confirmed that the kneading apparatus of this example can plasticize and measure the molten resin at a low pressure as compared with the kneading apparatus having the conventional sealing mechanism, and has a high plasticizing ability.

  The vent port 203 of the plasticizing cylinder 210 is connected to the vacuum pump 220 and the exhaust pipe via the buffer container 219. Therefore, the inside of the plasticizing cylinder 210 is depressurized by connecting the high-pressure kneading zone 22 and the depressurizing zone 23 and operating the vacuum pump 220. In this embodiment, after the pressurized fluid is retained in the high-pressure kneading zone 22, the number of reverse rotations of the screw 20 is reduced (the number of rotations: 30 rpm), and the upstream and downstream seal rings 40, 60 are restored. , The tapered surfaces of the truncated cone portions 31 and 51 and the tapered surfaces of the tapered portions 42 and 62 are separated from each other, and the inner peripheral surfaces of the upstream and downstream seal rings 40 and 60 and the outer periphery of the screw 20 are separated. The gap G between the surfaces was opened, and the gasified carbon dioxide was exhausted from the vent port 203. At this time, resin vent-up did not occur from the vent port 203.

  Next, the screw 20 was returned to the normal rotation, and the molten resin was sent to the tip of the screw 20 to complete the plasticization measurement, and the molten resin was injected and filled into the cavity 253. Since the obtained molded body was colored brown, it was confirmed that the organometallic complex was introduced into the molten resin. Moreover, in order to confirm that the organometallic complex was well dispersed in the molded body, the obtained molded body was plated. In the plating treatment, in order to swell the surface of the molded body, the molded body was immersed in an 80 ° C. aqueous solution containing 50% by volume of 1,3-butanediol for 5 minutes. Next, a general-purpose NiP electroless plating process was performed on the molded body to form a metal film on the entire surface. Furthermore, a 20 μm electrolytic copper plating film, a 10 μm electrolytic nickel plating film, and a 0.5 μm electrolytic chrome plating film were successively formed on the metal film in order. The obtained plated product was held at 120 ° C. for 1 hour, and then subjected to a thermal shock test in which a cycle of holding at −40 ° C. for 1 hour was repeated 100 times. After the test, visual inspection was performed visually. As a result, it was confirmed that a plating film having excellent adhesion was formed without causing swelling or cracking in the plating film.

  Moreover, when the above molding was repeated and the internal pressure of the resin in the high-pressure kneading zone 22 at the time of contact kneading on the 1000th shot was measured, it was 1 to 8 MPa, which was the same pressure as the pressure on the first shot. Therefore, according to the present Example, it was confirmed that a thermoplastic resin molding can be manufactured stably for a long period of time.

(Example 2)
In this example, a thermoplastic resin molded body in which a functional material was dispersed was manufactured by injection molding using the same kneading apparatus 200 and molding machine 1000 as in Example 1. Amorphous nylon (manufactured by Japan M Chemie, Glibori TR55) was used as the thermoplastic resin, heptafluorobutyric acid silver salt (I) as an antibacterial agent was used as the functional material, and ethanol was used as the solvent. The introduction amount was adjusted so that the concentration of carbon dioxide was about 6% by mass and the concentration of the antibacterial agent was 400 ppm with respect to the mass of the molten resin for each shot.

  First, the pressurized fluid was prepared by the pressurized fluid supply device 100 in the same manner as in Example 1, and the thermoplastic resin was melted by the kneading device 200. When the molten resin is sent to the high-pressure kneading zone 22, the screw 20 is temporarily stopped in the same manner as in the first embodiment, and then the screw 20 is rotated in the reverse direction (rotation speed: 50 rpm), so that the upstream side and downstream side seal rings 40. , 60 are moved to the upstream side so that the tapered surfaces of the truncated cone portions 31, 51 and the tapered surfaces of the tapered portions 42, 62 are brought into contact with each other, so that the high-pressure kneading zone 22, the decompression zone 23, and the plasticizing zone 21 are Shut off.

  Next, in this embodiment, while continuously introducing the pressurized fluid by the flow rate control, the reverse rotation speed of the screw 20 is decreased (rotation speed: 20 rpm), and the upstream and downstream seal rings 40, By slightly moving 60 to the downstream side, the tapered surfaces of the truncated cone portions 31 and 51 and the tapered surfaces of the tapered portions 42 and 62 were separated from each other. As a result, the gap G between the inner peripheral surfaces of the upstream and downstream seal rings 40 and 60 and the outer peripheral surface of the screw 20 was slightly opened, and the gasified carbon dioxide was exhausted. Furthermore, the high-pressure kneading zone 22 and the pressure-reducing zone 23 were repeatedly connected and disconnected by changing the reverse rotation speed of the screw 20 in small increments (rotation speed: 20 to 50 rpm). At this time, the resin internal pressure of the high-pressure kneading zone 22 fluctuated in the range of 5 to 10 MPa. Further, resin vent-up did not occur from the vent port 203.

Next, in the same manner as in Example 1, the screw 20 was returned to the normal rotation, the molten resin was sent to the tip of the screw 20, the plasticizing measurement was completed, and the cavity 253 was injected and filled with the molten resin. About the obtained molded object, using a Staphylococcus aureus and Escherichia coli, unified test method (JIS)
Antibacterial evaluation was performed at Z 2911). As a result, the molded product had a high antibacterial action, and it was confirmed that the antibacterial agent was well dispersed in the molded product. Therefore, according to the present embodiment, the molten resin and the pressurized fluid can be repeatedly contact-kneaded while suppressing the resin internal pressure in the high-pressure kneading zone 22 from becoming excessively high. Even in a state where the supply of the molten resin from the upstream to the high-pressure kneading zone 22 is suppressed, by connecting the high-pressure kneading zone 22 and the decompression zone 23, a part of the high-pressure carbon dioxide in the high-pressure kneading zone 22 is gas. The gasified carbonized carbon dioxide can be exhausted from the decompression zone 23. As a result, when a pressurized fluid containing high-pressure carbon dioxide and a functional material is used, in the high-pressure kneading zone 22 near the decompression zone 23, the functional material that has become insoluble in high-pressure carbon dioxide due to decompression remains in the molten resin. I can let you. Therefore, the functional material can be introduced into the molten resin at a high concentration by repeated contact kneading between the molten resin and the pressurized fluid.

  The above molding was repeated, and the internal pressure of the resin in the high-pressure kneading zone 22 at the time of contact kneading on the 1000th shot was 5 to 10 MPa, which was the same pressure as the pressure on the first shot. Therefore, according to the present Example, it was confirmed that a thermoplastic resin molding can be manufactured stably for a long period of time.

(Example 3)
In the present embodiment, thermoplasticity in which functional materials are dispersed using the kneading apparatus 200 having the sealing mechanism having the form of FIG. 5 as the upstream and downstream sealing mechanisms S1 and S2 and the molding machine 1000 shown in FIG. A resin molding was produced by injection molding. Further, the same thermoplastic resin, functional material, and solvent as those in Example 1 were used, and the amounts of carbon dioxide and functional material introduced were also adjusted in the same manner as in Example 1.

  First, the pressurized fluid was prepared by the pressurized fluid supply device 100 in the same manner as in Example 1, and the thermoplastic resin was melted by the kneading device 200. When the molten resin was sent to the high-pressure kneading zone 22, the rotation of the screw 20 was temporarily stopped, and then the screw 20 was reversely rotated to move the upstream and downstream seal rings 40, 60 to the upstream side. As a result, the tapered surfaces of the truncated cone portions 31 and 51 and the tapered surfaces of the tapered portions 42 and 62 were brought into contact with each other, and the high-pressure kneading zone 22, the decompression zone 23, and the plasticizing zone 21 were blocked.

  Next, in this example, the pressurized fluid is intermittently introduced by the flow rate control so that the pressurized fluid stays in the high-pressure kneading zone 22 for 1 second, and after the molten resin and the pressurized fluid are contact-kneaded, The screw 20 is returned to the normal rotation, and the upstream and downstream seal rings 40, 60 are moved downstream to separate the tapered surfaces of the truncated cone parts 31, 51 from the tapered surfaces of the tapered parts 42, 62, A gap G between the inner peripheral surface of the upstream and downstream seal rings 40 and 60 and the outer peripheral surface of the screw 20 was opened. The resin internal pressure during contact kneading was 1 to 8 MPa. Then, after the gasified carbon dioxide was exhausted while the molten resin was being sent to the decompression zone 23, the plasticization measurement was completed in the same manner as in Example 1, and the molten resin was injected and filled into the cavity 253. When a plated product was produced using the obtained molded body in the same manner as in Example 1, it was confirmed that a plating film having excellent adhesion was formed.

  Moreover, when the above molding was repeated and the internal pressure of the resin in the high-pressure kneading zone 22 at the time of contact kneading on the 1000th shot was measured, it was 1 to 8 MPa, which was the same pressure as the pressure on the first shot. Therefore, according to the present Example, it was confirmed that a thermoplastic resin molding can be manufactured stably for a long period of time.

  Although the present invention has been described in detail above, the present invention can be summarized as follows from the above embodiments.

One aspect of the present invention includes a plasticizing cylinder and a screw disposed in the plasticizing cylinder so as to be rotatable and movable back and forth, and a molten resin obtained by plasticizing a thermoplastic resin in the plasticizing cylinder; A high-pressure kneading zone for contact-kneading a pressurized fluid containing high-pressure carbon dioxide, and a decompression zone for separating the gasified carbon dioxide from the molten resin in which the pressurized fluid is contact-kneaded by reducing the internal pressure of the resin. A kneading device formed adjacent in this order from the upstream side,
A downstream seal mechanism is provided between the high-pressure kneading zone and the pressure-reducing zone to communicate and block the high-pressure kneading zone and the pressure-reducing zone according to the rotational state of the screw.

  According to the above kneading apparatus, the downstream side seal mechanism for connecting and blocking the high pressure kneading zone and the reduced pressure zone according to the rotational state of the screw is provided between the high pressure kneading zone and the reduced pressure zone. Since no reaction force is generated by the spring between the pressure reducing zone and the decompression zone, a high plasticizing ability can be obtained. Further, since the downstream seal mechanism communicates and blocks the high-pressure kneading zone and the decompression zone according to the rotational state of the screw, the sealing performance does not deteriorate even when used for a long time.

  The downstream seal mechanism may block the high-pressure kneading zone and the decompression zone by reverse rotation of the screw. Further, the downstream side seal mechanism communicates the high pressure kneading zone and the pressure reduction zone by either forward rotation of the screw, stoppage of rotation of the screw, or reduction in the rotational speed of reverse rotation of the screw. May be.

  According to the kneading apparatus, the high-pressure kneading zone and the decompression zone can be communicated and blocked at a desired timing according to the rotational state of the screw.

Preferably, in the kneading apparatus,
The downstream-side seal mechanism is disposed between the high-pressure kneading zone and the pressure-reducing zone, and has a reduced diameter portion of the screw having a seal portion, and is fitted on the reduced diameter portion of the screw so as to be movable in the axial direction. A seal ring having a contact surface in contact with the seal portion,
When the seal portion of the reduced diameter portion and the contact surface of the seal ring are separated according to the rotation state of the screw, the high pressure kneading zone and the reduced pressure zone communicate with each other, and the seal portion of the reduced diameter portion and the When the contact surface of the seal ring comes into contact, the high-pressure kneading zone and the decompression zone are blocked.

  According to the kneading apparatus, the high-pressure kneading zone and the depressurization zone are communicated with each other and blocked by the seal portion of the reduced diameter portion of the screw and the contact surface of the seal ring being separated and brought into contact in accordance with the rotational state of the screw. Can do.

Preferably, in the kneading apparatus,
The screw includes a locking portion, and the seal ring includes a locked portion that engages and disengages with the locking portion of the screw.
When the screw is reversely rotated at a predetermined rotational speed or more, the locking portion of the screw and the locked portion of the seal ring are engaged, and the screw and the seal ring rotate together. The contact state between the seal portion of the reduced diameter portion and the contact surface of the seal ring is maintained.

  According to the above kneading apparatus, since the seal ring and the screw rotate together in an engaged state while the screw is rotating in the reverse direction at a predetermined rotational speed or more, the high-pressure kneading zone and the decompression zone can be reliably shut off. it can. Moreover, according to the rotation speed of a screw, a high pressure kneading zone and a pressure reduction zone can be connected and interrupted | blocked.

In the plasticizing cylinder, when a plasticizing zone is formed adjacent to the upstream side of the high-pressure kneading zone to plasticize the thermoplastic resin into a molten resin,
Preferably, the kneading device includes an upstream side sealing mechanism that communicates and blocks the plasticizing zone and the high-pressure kneading zone between the plasticizing zone and the high-pressure kneading zone according to a rotational state of the screw. Prepare.

  According to the above kneading apparatus, since the upstream side sealing mechanism for connecting and blocking the plasticizing zone and the high pressure kneading zone is also provided upstream of the high pressure kneading zone, the sealing performance of the high pressure kneading zone can be further improved. it can.

Another aspect of the present invention is a method for producing a thermoplastic resin molded body using the kneading apparatus described above,
A kneading step of shutting off the high-pressure kneading zone and the decompression zone with the downstream-side seal mechanism, and contacting and kneading the molten resin and the pressurized fluid under high pressure;
From the molten resin in which the pressurized fluid is contact-kneaded by causing the downstream-side seal mechanism to communicate the high-pressure kneading zone and the pressure-reducing zone to reduce the resin internal pressure of the molten resin in which the pressurized fluid is contact-kneaded. A separation step of separating the gasified carbon dioxide.

  According to the above production method, in the kneading step, the molten resin and the pressurized fluid can be contact-kneaded in a state where high sealing performance of the high-pressure kneading zone is ensured. In the separation step, the internal pressure of the resin can be quickly reduced, and the smoothly gasified carbon dioxide can be separated from the molten resin and exhausted.

Preferably, in the method for producing the thermoplastic resin molded body,
The kneading step and the separating step may be repeated a plurality of times while the molten resin is retained in the high-pressure kneading zone.

  According to the above production method, the molten resin having a low concentration of high-pressure carbon dioxide and the pressurized fluid can be repeatedly contact-kneaded by the separation step. Therefore, even if the solubility of high-pressure carbon dioxide in the molten resin is low, a large amount of high-pressure carbon dioxide can be introduced into the molten resin. Further, when a pressurized fluid containing a functional material is used, a large amount of the functional material can be introduced into the molten resin.

  In the manufacturing method, the pressurized fluid may include a functional material. According to the said manufacturing method, the thermoplastic resin molding in which the functional material was disperse | distributed favorably can be manufactured.

  As described above, according to the present invention, a pressurized fluid containing high-pressure carbon dioxide is introduced into a plasticizing cylinder, and the pressurized fluid and the molten resin obtained by plasticizing the thermoplastic resin are contact-kneaded in the plasticizing cylinder. When producing thermoplastic resins, a kneading apparatus capable of obtaining a high plasticizing ability and stably producing a thermoplastic resin molded article for a long period of time and a method for producing a thermoplastic resin molded article are provided. can do.

  As mentioned above, although this invention was demonstrated with reference to embodiment and an Example, this invention is not limited to the said embodiment and Example. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention.

According to the present invention, when a thermoplastic resin molded body is produced using a pressurized fluid containing high-pressure carbon dioxide, the high-pressure state of the high-pressure kneading zone in which the molten resin and the pressurized fluid are contact-kneaded is maintained over a long period of time. It can be kept stable. Therefore, according to the present invention, various types such as a molded body modified with high-pressure carbon dioxide, a molded body with a reduced residual solvent, an alloyed molded body, and a molded body with a functional material dispersed therein, etc. A thermoplastic resin molding can be manufactured industrially stably.

Claims (3)

A plasticizing cylinder; and a screw disposed in the plasticizing cylinder so as to be rotatable and movable back and forth. In the plasticizing cylinder, a molten resin obtained by plasticizing a thermoplastic resin and a pressurized fluid are contact-kneaded. A kneading apparatus in which a high-pressure kneading zone and an adjacent zone adjacent to the high-pressure zone are formed,
A seal mechanism is provided between the high-pressure kneading zone and the adjacent zone to communicate and block the high-pressure kneading zone and the adjacent zone according to the rotational state of the screw.
The seal mechanism is a mechanism that blocks the high-pressure kneading zone and the adjacent zone according to the rotational state of the screw, and has a reduced diameter portion of the screw having a seal portion, and a reduced diameter portion of the screw. A seal ring that has a contact surface that is movably fitted in a direction and abuts against the seal portion;
When the seal portion of the reduced diameter portion and the contact surface of the seal ring are separated according to the rotation state of the screw, the high pressure kneading zone and the adjacent zone communicate with each other, and the seal portion of the reduced diameter portion and the A kneading device in which the high-pressure kneading zone and the adjacent zone are shut off when the contact surface of the seal ring comes into contact. The kneading apparatus according to claim 1,
The screw includes a locking portion, and the seal ring includes a locked portion that engages and disengages with the locking portion of the screw.
When the screw is reversely rotated at a predetermined rotational speed or more, the locking portion of the screw and the locked portion of the seal ring are engaged, and the screw and the seal ring rotate together. The kneading apparatus in which the contact state between the seal portion of the reduced diameter portion and the contact surface of the seal ring is maintained.   The kneading apparatus according to claim 1 or 2, wherein the sealing mechanism is a mechanism that blocks the high-pressure kneading zone and the adjacent zone by reverse rotation of the screw.

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