JP2008062595A - Rotary valve for injection molding machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotary valve for an injection molding machine capable of injecting a mixture of a supercritical fluid and the dissolved substance of the same and preventing back flow of the mixture when plasticizing, infiltrating, and injecting. <P>SOLUTION: The rotary valve 10 comprises a rotary casing 11 having a molten resin inlet path 12 and a molten resin outlet path 13 and a valve bore 14 opening to the mixture injecting hole 16. A molten resin passing hole 24, a concave groove 25 through which the mixture flows, and a land portion 26 are arranged in a rotor 20, the rotor is driven to a first position, thereby the inlet path and the outlet path are blocked and the concave groove is blocked at the same time to make it possible to plasticize and infiltrate. The rotor is driven to a second position, thereby the inlet path and the outlet path are blocked, the mixture injecting hole is communicated to the inlet path via the concave groove to make it possible to inject the mixture. The rotor is driven to a third position, thereby the inlet path and the outlet path are communicated with each other via the passing hole of the rotor, the mixture injecting hole is closed by the land portion and the mixture can be injected. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a rotary valve of an injection molding machine, more specifically, a heating cylinder, a shut-off device attached to the front of the heating cylinder, and an injection nozzle attached to the tip of the shut-off device. The shutoff device is closed, the screw provided in the heating cylinder is plasticized by driving in the rotational direction, and the plasticized molten resin is opened by opening the shutoff device and driving the screw in the axial direction. The present invention relates to a rotary valve of an injection molding machine adapted to inject from the injection nozzle.

In general, there are many plastic molded products molded by injection molding, but the physical properties are determined by the resin material to be plasticized and melted. Depending on the application, the plastic molded product may be printed, painted, etc. on its surface, and may be subjected to the formation of a conductor or a metal film, the bonding between the molded products, and other post-processing. When it is necessary to perform such post-processing, generally, the surface of a plastic molded article is activated to improve the surface in order to improve processability. For example, electroless plating is widely adopted as a means for forming a metal conductive film on the surface of an electronic device made of a plastic molded product. However, the electroless plating process requires complicated steps such as degreasing, etching, wetting, catalyst, and accelerator, which is expensive and requires a lot of harmful substances, and there is also a problem in the treatment of waste liquid. .
Therefore, Patent Document 1 proposes a surface modification method for modifying a surface so that it can be applied to electroless plating entirely or selectively at the time of injection molding without passing through such complicated steps. Yes.

Japanese Patent No. 3696878.

  The injection molding machine described in Patent Document 1 is configured as schematically shown in FIG. That is, it comprises a plasticizing cylinder 140 in which a band heater 139 is wound on the outer periphery, and a screw 107 provided in the plasticizing cylinder 140 so as to be driven in the rotational direction and the axial direction. An injection nozzle 108 is attached in front of the plasticizing cylinder 140, and a shutoff valve 105 is provided in the injection nozzle 108. Further, a supply port 106 for the supercritical fluid and its melt is provided between the shutoff valve 105 and the screw 107.

  Therefore, when the shut-off valve 105 is closed and the screw 107 is driven to rotate, the pellet-shaped resin supplied from the hopper 110 is plasticized and melted and accumulated in the front 111 in the course of being sent forward as is conventionally known. The When the predetermined amount is accumulated, the screw 107 is driven rearward, that is, sucked back to reduce the pressure inside the front 111 and the solenoid valve 109 is opened. Then, the supercritical fluid supplied from the supercritical fluid generator 112 is mixed with a dissolved material such as a metal complex in the container 123 and injected into the front 111 from the supply port 106. The electromagnetic valve 109 is closed, and the screw 107 is driven forward by a predetermined amount. Then, the inside of the front 111 is pressurized to 10 MPa, and the supercritical fluid and its melt penetrate into the molten resin. Next, the shutoff valve 105 is opened, and the screw 107 is driven in the injection direction. If it does so, the molten resin which the supercritical fluid and its melt | dissolution osmose | permeated will be inject | poured and filled in the cavity of the metal mold | die not shown. As a result, a molded product having a modified surface as described in Patent Document 1 is obtained.

According to the injection molding machine proposed by the above-mentioned Patent Document 1, the surface modification of the molded product is performed by disposing a melt such as a metal complex on the surface of the stamper of the mold, and the conventional electroless plating process There is an advantage that electroless plating can be performed without performing a complicated process.
However, there are problems to be improved, in particular, points to be improved for injection molding machines. For example, a supply port 106 for injecting a supercritical fluid and a dissolved substance such as a metal complex is located between the shut-off valve 105 and the screw 107, and a high injection pressure acts on the supply port 106 during injection filling. . Therefore, the supply port 106 is in an “open” state when the supercritical fluid and its melt are injected, and is in a “closed” state so that the molten resin does not flow backward when the molten resin is metered or plasticized. The opening / closing mechanism 109 having a backflow prevention function is required, and the opening / closing mechanism 109 needs to have sufficient strength to withstand a high injection pressure. In fact, the injection pressure is over 200 MPa, and the opening / closing mechanism 109 that can withstand such high pressures and can inject the supercritical fluid and its melt without delay selects a special material. Even if it is manufactured in a simple shape and structure, there is no guarantee that sufficient quality and performance can be achieved. Furthermore, when the injection nozzle 108 is moved forward most, such as during molding, the supply port 106, the opening / closing mechanism 109, etc. may enter the inside of the fixed platen 125. May be subject to a design constraint that it must have a minimum dimension so as not to interfere with the inner wall surface of the stationary platen 125.

  An object of the present invention is to provide an injection molding machine that has solved the above-described conventional problems or problems, and specifically, a function provided by a conventional shut-off valve and a supply port provided with a backflow prevention mechanism The purpose of the present invention is to provide a rotary valve for an injection molding machine having both functions at the same time, and more specifically, it can inject a supercritical fluid and its melt as well as a shut-off function. It is an object of the present invention to provide a rotary valve for an injection molding machine that can reliably block the backflow of molten resin to a supply port during plasticizing and injection filling. It is another object of the present invention to provide a rotary valve for an injection molding machine that is simple in structure and operation and is therefore inexpensive. Another object of the present invention is to provide a rotary valve for an injection molding machine that is small in size and does not require a special arrangement space.

  In order to achieve the above object, the present invention is applied with a rotary valve that is specially configured to perform both functions of a shut-off valve function and an opening / closing mechanism or a check valve function. The rotary valve having both functions is constituted by a heating cylinder block attached to the front of the heating cylinder, that is, a rotor casing, and a rotor that is rotationally driven in a valve bore of the rotor casing. The rotor casing is formed with a molten resin inlet passage communicating with the heating cylinder, a molten resin injection material outlet passage communicating with the injection nozzle, and a mixture injection hole opened to the outside. The rotor has a cylindrical shape. A molten resin injection material passage hole is formed in the rotor in the diameter direction. In addition, a mixture flow path through which the mixture of the supercritical fluid and its dissolved material flows is formed at a position where it does not interfere with the passage hole. The mixture flow path is preferably configured as a concave groove formed by partially cutting the outer periphery of the rotor to a predetermined depth. The rotor is configured to take the first, second and third positions, that is, the plasticizing position (mixture penetration position), the mixture injection position, and the injection / filling position.

Thus, in order to achieve the above object, the invention according to claim 1 is attached to the heating cylinder, the shut-off device attached to the front end of the heating cylinder, and the tip of the shut-off device. The injection nozzle is closed, the shut-off device is closed, the screw provided in the heating cylinder is plasticized by driving in the rotational direction, and the plasticized molten resin is opened by opening the shut-off device. In the injection molding machine that is driven in the axial direction and is injected from the injection nozzle, the shutoff device includes a rotor casing and a rotor that is rotationally driven in a valve bore of the rotor casing. A rotary valve consisting of the inside of the rotor casing, one in communication with the weighing chamber of the heating cylinder, A molten resin inlet passage that opens to the valve bore, and a molten resin injection material outlet passage that opens to the valve bore and communicates with the injection nozzle on one side are formed. A mixture supply port reaching the valve bore for injecting fluid and its lysate is provided;
The rotor has a molten resin injection material passage hole, a mixture flow path through which a supercritical fluid and a melt thereof flow, and a land portion that is in liquid-tight or air-tight contact with the valve bore of the rotor casing and has a sealing action. When the rotor is rotationally driven in the valve bore and takes the first position, the molten resin inlet path and the molten resin injection material outlet path of the rotor casing are cut off, and the mixture flow path is also When the rotor is rotationally driven in the valve bore and takes the second position, the molten resin inlet path and the molten resin injection material outlet path of the rotor casing are cut off from the molten resin inlet path and the molten resin injection material outlet path. Is in a shut-off state, and the mixture supply port is in communication with the molten resin inlet passage through the mixture passage, and the rotor is disposed in the valve bore. When the rotor is driven to take the third position, the molten resin inlet channel and the molten resin injection material outlet channel of the rotor casing are in communication with each other, and the mixture channel is connected to the molten resin inlet channel and the molten resin injection material outlet. It is configured so as to be cut off from the road.
According to a second aspect of the present invention, in the rotary valve according to the first aspect, the molten resin injection material passage hole and the mixture flow path of the rotor are formed on substantially the same plane parallel to the transverse section of the rotor. According to a third aspect of the present invention, in the rotary valve according to the first or second aspect of the present invention, the mixture flow path is configured to be a concave groove formed by partially cutting the outer periphery of the rotor to a predetermined depth. Is done.

  As described above, according to the present invention, by controlling the rotation of the rotor of the rotary valve, not only a function as a shut-off device but also a function for injecting a supercritical fluid and its melt can be added. When the rotor is in the first position, that is, when plasticizing and when the supercritical fluid and its melt are infiltrated into the molten resin, the molten resin inlet passage and the molten resin injection material outlet passage of the rotor casing are blocked. In addition, the mixture flow path of the rotor is also blocked from the molten resin inlet path and the molten resin injection material outlet path. Further, when the rotor takes the third position, that is, at the time of injection / filling, the molten resin inlet passage and the molten resin injection material outlet passage of the rotor casing are in communication with each other, and the mixture flow passage of the rotor is connected to the molten resin inlet. It is cut off from the channel and the molten resin injection material outlet channel. Therefore, according to the present invention, there is no need for an opening / closing mechanism having a backflow prevention function considering high injection pressure, such as an opening / closing valve or a check valve of a conventional apparatus, which improves quality and performance, and is compact and inexpensive An effect peculiar to the present invention that a rotary valve for an injection molding machine can be provided is obtained. Furthermore, it is only necessary to control the rotor to take the first to third positions, that is, by simple operation, plasticization, injection of the mixture into the molten resin, penetration of the mixture and injection and filling of the penetrated molten resin injection material. The effect that it can do is also acquired. In addition, the rotary valve according to the present invention has both a shut-off device function and a mixture supply function, so that it is small in size and does not require any special arrangement space. Furthermore, according to the invention in which the mixture flow path is a concave groove having a shape obtained by partially cutting the outer peripheral portion of the rotor to a predetermined depth, an effect that processing is simple and can be provided at a lower cost is further obtained.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a view showing an injection molding machine according to the present embodiment, in which (a) is the whole, and (b), (c) and (d) are enlarged cross sections showing different operation stages of the rotary valve. FIG. The injection molding machine 1 includes a heating cylinder 2 as is conventionally known. An injection nozzle 3 is attached in front of the heating cylinder 2 via a cylinder block SB. A plurality of band heaters 4, 4,... Are individually provided on the outer peripheral portions of the heating cylinder 2, the cylinder block SB, and the injection nozzle 3. A cylinder bore 5 is formed in the axial direction inside the heating cylinder 2. The cylinder bore 5 communicates with the molten resin passage 6 in the cylinder block SB and the molten resin injection material passage 7 in the injection nozzle 3. As is well known in the art, the bore 5 of the heating cylinder 2 is provided with a screw 8 that is driven in the rotational direction and the axial direction. A screw head is attached to the tip of the screw 8, and the inside of the bore 5 of the heating cylinder 2 in front of the screw head is a measuring chamber 9.

  A rotary valve 10 is provided in the cylinder block SB configured as described above. Since the rotary valve is composed of a rotor casing and a rotor that is driven to rotate or swing in the valve bore of the casing, the cylinder block SB is the rotor casing 11 in the illustrated embodiment. As described above, the molten resin passage 6 is formed in the rotor casing 11 in the axial direction, but this passage 6 is interrupted by the valve bore 14 and heated rightward in FIGS. A portion connected to the cylinder 2 is a molten resin inlet passage 12, and a portion connected to the left injection nozzle 3 is a molten resin injection material outlet passage 13. These inlet passage 12 and outlet passage 13 are interrupted by a valve bore 14 but are aligned in the axial direction. A mounting portion 15 having a female screw for connecting a supply pipe for a mixture of the supercritical fluid and the melt thereof is formed at a predetermined position on the outer peripheral portion of the rotor casing 11. The mixture injection hole 16 extending from the attachment portion 15 opens in the valve bore 14 of the rotor casing 11 as shown in an enlarged view in FIG. The position where the mixture injection hole 16 is open is a position corresponding to the concave groove 25.

  The rotor 20 that is rotationally driven in a fluid-tight or air-tight manner in contact with the inner peripheral wall of the valve bore 14 of the rotor casing 11 is shown in an enlarged manner in FIGS. In addition, it has a substantially cylindrical shape. Then, shafts 21 and 22 are provided at both ends thereof, and ring brackets are attached to the shafts 21 and 22 at both ends as described in detail with reference to FIG. A molten resin injection material passage hole 24 is formed in the diameter direction at a substantially central portion in the axial direction of the rotor 20 having such a shape. As will be described in detail later, the molten resin injection material passage hole 24 is aligned with the molten resin inlet passage 12 and the molten resin injection material outlet passage 13 of the rotor casing 11 during injection filling. Further, a concave groove 25 is formed on the outer peripheral surface of the rotor 20 by cutting off a part of the arc into a groove shape. A mixture of the supercritical fluid and its melt is injected into the molten resin inlet channel 12 from the concave groove 25.

  As shown in FIG. 2B, the molten resin injection material passage hole 24 has an inlet opening end portion 24a and an outlet opening end portion 24b, and is formed substantially in the diameter direction of the rotor 20. However, the bottom wall of the groove 25 is not parallel to the molten resin injection material passage hole 24. That is, the arc portion 26 formed by the outlet notch end portion 25a of the concave groove 25 and the inlet opening end portion 24a of the molten resin injection material passage hole 24 has an inlet notch end portion 25b of the concave groove 25 and the molten resin injection material passage hole 24. It is larger than the circular arc portion 27 formed by the outlet opening end 24b. Moreover, the molten resin injection material passage hole 24 and the concave groove 25 are formed in the same plane as a cross section obtained by cutting the rotor 20 in a direction perpendicular to the axis. The state formed in the same plane is shown in FIG. Thus, since the molten resin injection material passage hole 24 and the concave groove 25 are formed on the same surface, the rotor 20 rotates at the same position and the angle of the molten resin injection material passage hole 24 and the concave groove 25 changes. And are aligned with the molten resin inlet passage 12 together. Moreover, although formed in the same surface, it is formed in the position which does not interfere mutually. Therefore, no matter what position the rotor 20 takes, the molten resin injection material, the supercritical fluid, and the melted material thereof are not mixed in the rotary valve 10. An arc portion formed by the outlet notch end portion 25 a of the concave groove 25 and the inlet opening end portion 24 a of the molten resin injection material passage hole 24 is a land portion 26. The land portion 26 closes the molten resin inlet passage 12 during measurement. Moreover, the mixture injection hole 16 is closed at the time of injection filling.

  For driving the rotor 20 of the rotary valve 10 configured as described above, in the present embodiment, as shown in FIG. 1A, an actuator 30 composed of, for example, a piston cylinder unit is applied. . The piston rod of the actuator 30 is connected to both end shafts 21 and 22 so as to sandwich the rotor 20 via the link brackets 31 and 32 and the like in a conventionally known manner. When the piston of the actuator 30 moves in three stages, the rotor 20 takes three different positions as will be described in the next section.

  Next, the operation of the above embodiment will be described. The rotor 20 of the rotary valve 10 is rotationally driven by an actuator 30 to a closed position or a plasticizing position shown in FIG. That is, the molten resin injection material passage hole 24 of the rotor 20 is disengaged from the molten resin inlet passage 12 of the rotor casing 11, and the land portion 26 of the rotor 20 is driven to a position where the molten resin injection passage 12 is blocked. At this position, the gap between the concave groove 25 and the molten resin inlet passage 12 is also blocked. A pellet-shaped resin material is supplied to the heating cylinder 2 while rotating the screw 8. The resin material is melted by heat generated by frictional force, shearing force, etc. due to the rotation of the screw 8 and heat applied from the band heaters 4, 4,. Is done. The screw 8 moves backward by the pressure of the accumulated molten resin. Plasticization ends when a predetermined amount is weighed.

  The screw 8 is retracted and sucked back. As a result, the pressure in the measuring chamber 9 decreases. The rotor 20 of the rotary valve 10 is rotationally driven to reach the mixture injection position shown in FIG. That is, the molten resin injection material passage hole 24 of the rotor 20 is driven to a position where the concave groove 25 of the rotor 20 communicates with the molten resin injection passage 12 while leaving the molten resin injection passage 12 of the rotor casing 11. Then, a supercritical fluid and a mixture thereof, for example, a mixture of a metal complex, are injected from the mixture injection hole 16 through the concave groove 25 into the molten resin inlet passage 12.

  When the predetermined amount is injected, the rotor 20 is rotationally driven to the closed position shown in FIG. At this position, the land 26 of the rotor 20 closes the molten resin inlet passage 12 of the rotor casing 11, and the groove 25 of the rotor 20 and the molten resin inlet passage 12 are also blocked. The screw 8 is advanced by a predetermined amount so that the internal pressure becomes about 10 MPa, for example. By this pressurization, the supercritical fluid and its melt penetrate into the plasticized molten resin and become a molten resin injection material.

  The rotor 20 is set to the injection / filling position shown in FIG. That is, the molten resin injection material passage hole 24 of the rotor 20 is driven to a position communicating with the molten resin inlet passage 12 and the molten resin injection material outlet passage 13 of the rotor casing 11. In this position, the mixture injection hole 16 is closed by the land 26 of the rotor 20, and the concave groove 25 is also isolated from these inlet / outlet passages 12, 13. The molten resin injection material infiltrated with the supercritical fluid and its melt is injected into a mold cavity (not shown) by driving the screw 8 in the axial direction. Wait for cooling to solidify and open the mold. As a result, a molded article having a modified surface as shown in Patent Document 1 is obtained. Thereafter, molding is performed in the same manner.

  The rotary valve 10 of the present invention can be implemented in various forms without being limited to the above embodiment. For example, in the above-described embodiment, the concave groove 25 is formed in a groove shape in which the arc portion of the rotor 20 is cut out, and is formed in a groove shape having an open outer radius. Obviously, it can be implemented as a through hole. Further, although the concave groove 25 and the molten resin injection material passage hole 24 are formed on substantially the same surface, the concave groove 25 can be implemented even if it is inclined with respect to a cross section perpendicular to the axis. In this way, when the rotor 20 is rotated to the mixture injection position, the outlet notch end 25a of the concave groove 25 may be aligned with the molten resin inlet passage 12 of the rotor casing 10. Furthermore, by adding axial movement to the rotation of the rotor 20, the formation position, shape, etc. of the concave groove 25, the molten resin injection material passage hole 24, the mixture injection hole 16, and the land portion 26 can be accommodated. It can also be implemented.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows embodiment of this invention, (a) is the whole, (b), (c), and (d) are expanded sectional views which show the state which exists in each operation | movement stage of a rotary valve. It is. BRIEF DESCRIPTION OF THE DRAWINGS It is a perspective view of the rotor which concerns on embodiment of this invention, The (a) is the whole, The (b) is an expanded sectional view shown as a cross section. It is a schematic diagram which shows a part of conventional injection molding machine in cross section.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Injection molding machine 2 Heating cylinder 3 Injection nozzle 6 Molten resin passage 7 Molten resin injection material passage 8 Screw 10 Rotary valve 11 Rotor casing 12 Molten resin inlet passage 13 Molten resin injection material outlet passage 16 Mixture injection hole 20 Rotor 24 Molten resin injection Material passage hole 25 Concave groove 26 Land part

Claims (3)

A heating cylinder, a shut-off device attached to the front end of the heating cylinder, and an injection nozzle attached to the tip of the shut-off device. The shut-off device is closed to the heating cylinder. Injection in which a screw provided is plasticized by driving in a rotational direction, and the plasticized molten resin is injected from the injection nozzle by opening the shut-off device and driving the screw in the axial direction. In the molding machine,
The shut-off device is composed of a rotary valve including a rotor casing and a rotor that is oscillatingly driven in a valve bore of the rotor casing.
Inside the rotor casing, one is in communication with the weighing chamber of the heating cylinder, the other is in the molten resin inlet passage opened in the valve bore, and one is in the valve bore, and the other is in the melt communicated with the injection nozzle. A resin injection material outlet channel is formed, and a mixture supply port reaching the valve bore for injecting a supercritical fluid and a melt thereof is provided outside the rotor casing,
The rotor has a molten resin injection material passage hole, a mixture flow path through which a supercritical fluid and a melt thereof flow, and a land portion that is in liquid-tight or air-tight contact with the valve bore of the rotor casing and has a sealing action. Formed,
When the rotor is rotationally driven in the valve bore and takes the first position, the molten resin inlet passage and the molten resin injection material outlet passage of the rotor casing are cut off, and the mixture flow passage is also connected to the molten resin inlet. Is cut off from the path and the molten resin injection material outlet path,
When the rotor is rotationally driven in the valve bore and takes the second position, the molten resin inlet path and the molten resin injection material outlet path of the rotor casing are cut off, and the mixture supply port A state of communication with the molten resin inlet passage through the passage,
When the rotor is rotationally driven in the valve bore and takes the third position, the molten resin inlet passage and the molten resin injection material outlet passage of the rotor casing are in communication with each other, and the mixture flow passage is connected to the molten resin inlet. A rotary valve for an injection molding machine, wherein the rotary valve is cut off from the passage and the molten resin injection material outlet passage. The rotary valve according to claim 1, wherein the molten resin injection material passage hole and the mixture flow path of the rotor are formed on substantially the same plane parallel to the transverse section of the rotor. Rotary valve for molding machines. 3. The rotary valve for an injection molding machine according to claim 1, wherein the mixture flow path is a concave groove formed by partially cutting the outer periphery of the rotor to a predetermined depth.

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