JP5284814B2 - Circulating kneader - Google Patents

Description

  The present invention relates to a circulation kneader for kneading an object, and more particularly to a circulation kneader capable of suitably and quickly adjusting the temperature of an object during kneading.

  As an apparatus for producing a composite material by mixing polymer materials or a polymer material and an inorganic material, for example, a circulation kneader described in Patent Document 1 is known. This circulation type kneader includes a screw connected to a drive unit, a cylinder unit having a heating unit and a material charging unit arranged outside the screw, and an extrusion tip part disposed via a screw tip surface and a gap. And. A circulation path for circulating the resin is formed inside the screw, and the charged material (object) is kneaded while circulating in the cylinder and the screw.

  In such a circulating kneader, it is necessary to adjust the material to a predetermined temperature according to each step in each step of kneading. For this reason, a heating mechanism such as a heater, a cooling pipe through which a refrigerant flows, and the like are usually provided. Among these, it has been proposed that the cooling pipe is disposed inside the screw as in the device described in Patent Document 2 from the viewpoint of quickly taking away the heat generated from the material.

JP-A-2005-313608 JP-A-10-264233

  However, when a cooling pipe line is provided inside the screw as in the device described in Patent Document 2, the screw is excessively cooled. As a result, when starting the kneading operation again after the series of kneading operations is completed, it takes a long time to heat the material to the temperature required at the beginning of the kneading. Therefore, there is a problem in that production efficiency is lowered as a result of a long production lead time between kneading operations.

  On the other hand, when the heating temperature of the heating unit is raised in order to solve this, as a result of excessive heating of the parts other than the screw, the amount of heat generated adversely affects the control of shearing heat generated during kneading. Therefore, there is a problem that appropriate temperature control becomes difficult.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a circulating kneader capable of appropriately adjusting the temperature of the input material without reducing the production efficiency.

The present invention is a circulating kneader for kneading a material charged into a cylinder using a screw having a circulation path therein, and is a heating device that is embedded in a wall surface of the cylinder and heats the material in the cylinder. A mechanism, a cooling pipe provided around the cylinder to cool the material and the heating mechanism by flowing a refrigerant, a contact area between the wall surface and the refrigerant provided on the wall surface of the cylinder And an auxiliary pipe line for increasing the pressure.

According to the circulation type kneader of the present invention, the cylinder and the material in the cylinder are suitably and rapidly cooled without being excessively cooled by the refrigerant flowing through the cooling pipe.
Further, the heating mechanism can be efficiently cooled without excessively cooling the cylinder.

  The cooling pipe line may be divided into a first region and a second region so as not to communicate with each other by a partition wall that intersects the central axis of the cylinder. In this case, the cooling setting of the first region and the second region can be changed, and the temperature can be adjusted so that the circulation of the material in the cylinder becomes smooth.

  The first refrigerant may flow through the first area, and the second refrigerant may flow through the second area with at least one of temperature, flow rate, and material different from the first refrigerant. In this case, it can be easily set so that the first region and the second region have different cooling characteristics.

  According to the circulation type kneader of the present invention, the temperature of the charged material can be adjusted appropriately without reducing the production efficiency.

1 is an overall perspective view showing a circulating kneader according to a first embodiment of the present invention. It is sectional drawing of the kneading part and cooling part of the circulation type kneading machine. It is sectional drawing in the AA of FIG. It is sectional drawing in the BB line of FIG. It is an expanded sectional view which shows the front end side of the cylinder of the kneading part. It is a perspective view which decomposes | disassembles and shows the circulating kneader of 2nd Embodiment of this invention. It is sectional drawing of the kneading part and cooling part of the circulation type kneading machine. It is a figure which shows the result of having performed continuous kneading | mixing operation | work using the circulation type kneader of the Example of this invention, and the circulation type kneader of a comparative example.

A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is an overall perspective view showing a circulating kneader (hereinafter simply referred to as “kneader”) of the present embodiment.
As shown in FIG. 1, a kneading machine 1 includes a kneading unit 2 having a cylinder and a screw for kneading, a cooling unit 3 having a cooling pipe for cooling the kneading unit 2, and a drive for rotating the screw. Part 4.

FIG. 2 is a cross-sectional view of the kneading unit 2 and the cooling unit 3. The kneading section 2 includes a cylinder 5 into which a material to be kneaded is charged and a screw 6 inserted through the cylinder 5.
The cylinder 5 is formed to have a substantially cylindrical lumen. A temperature adjusting portion 7 for adjusting the internal temperature of the cylinder 5 is inserted into the distal end portion 5b of the cylinder 5, and a screw 6 is inserted from the base end portion 5c toward the intermediate portion 5a. The inner cavity of the cylinder 5 is kept airtight by the temperature control unit 7 and the screw 6 and functions as a kneading space in which materials are kneaded. The configuration and mounting mode of the temperature control unit 7 will be described later.

  Note that a nitride film may be formed on the inner surface of the cylinder 6 by ion implantation sputtering or the like, if necessary, in order to suppress the baking or modification of the material. As a material for forming the nitride film, various materials such as TiCN, TiN, CrN, CrTiN, and CrTiCN can be suitably employed.

The screw 6 includes a main body portion 8 that is inserted into the intermediate portion 5 a of the cylinder 5, and a flange 9 that is provided on the proximal end side of the main body portion 8.
The main body 8 has an outer diameter that is substantially the same as the inner diameter of the intermediate portion 5a of the cylinder 5, and a protrusion 8A extends in a spiral shape on the outer peripheral surface. A circulation path 10 is provided so as to substantially coincide with the central axis of the screw 6 from the tip of the main body 8. The circulation path 10 communicates with the outer peripheral surface of the main body 8 by a discharge hole 11 provided on the base end side. Thus, the material sent to the front end side of the main body 8 passes through the circulation path 10 and the discharge hole 11 and is sent again to the outer peripheral surface side of the main body 8 and is kneaded while circulating.

The flange 9 is formed to have a diameter larger than the outer diameter of the intermediate portion 5 a of the cylinder 5. And the main-body part 8 of the screw 6 is inserted in the lumen | bore of the base end part 5c of the cylinder 5 so that the flange 9 may contact | abut the rear end of the cylinder 5. FIG.
The base end of the screw 6 is connected to the drive unit 4, and is rotated around the axis by the rotation of the drive unit 4.

  The cooling unit 3 includes an exterior member 12 attached so as to surround the outside of the cylinder 5, and a cooling pipe line 13 provided in a gap between the exterior member 12 and the outer peripheral surface of the cylinder 5. As shown in FIG. 2, a certain gap is provided between the inner surface of the exterior member 12 and the outer peripheral surface of the cylinder 5, and this gap provided around the cylinder 5 is the cylinder 5 and the cylinder 5. It becomes the cooling conduit 13 for cooling the material inside.

  3 is a cross-sectional view taken along line AA in FIG. The upper wall surface 12A of the exterior member 12 is provided with an inflow port 14 for introducing a refrigerant into the cooling conduit 13, and the lower wall surface 12B facing the wall surface 12A flows through the cooling conduit 13. An outlet 15 is provided for discharging the refrigerant. A valve or the like (not shown) is attached to the inflow port 14 so that the presence / absence of the inflow of refrigerant and the flow rate can be controlled.

Although there is no restriction | limiting in particular in the position of the inflow port 14 and the outflow port 15, From a viewpoint of cooling the cylinder 5 uniformly, it is preferable to provide in the wall surface which each opposes. Further, from the viewpoint that gravity can be used for the circulation of the refrigerant, it is preferable to form the inlet 14 at the upper part and the outlet 15 at the lower part as in the present embodiment.
As the refrigerant flowing through the cooling pipe 13, various known refrigerants including water can be appropriately selected. Further, the flow rate may be set as appropriate.

  4 is a cross-sectional view taken along line BB in FIG. This BB line exists in the position with the material inlet 16 mentioned later. As shown in FIGS. 3 and 4, a part of the exterior member 12 extends to the inner cavity side and is connected to the outer wall of the cylinder 5. The lumen of the connected portion serves as a material inlet 16 for introducing a resin material to be kneaded into the cylinder.

  FIG. 5 is an enlarged cross-sectional view showing the temperature control unit 7. The temperature control unit 7 includes a plurality (four in this embodiment) of heaters (heating mechanisms) 17 for heating the cylinder 5 and a sensor 18 for measuring the temperature inside the cylinder 5. Yes.

  As shown in FIG. 5, the heater 17 is embedded so as to extend from the front end side of the cylinder 5 into the wall surface of the intermediate portion 5 a of the cylinder 5, and heats the inside of the cylinder 5 and the supplied kneaded resin material. As shown in FIG. 3, since the heater 17 is embedded in the wall surface of the cylinder 5, the heater 17 is closer to the cooling line 13 than the inner wall of the cylinder 5.

The sensor 18 is disposed so that the temperature of the kneaded resin material flowing in the circulation path can be measured. The sensor 18 may be appropriately selected as long as it can withstand the temperature of the resin material being kneaded.
The heater 17 and the sensor 18 are connected to a control unit (not shown), and the temperature in the cylinder is maintained within a predetermined range via the heater 17 based on the temperature value detected by the sensor 18.

  As the drive unit 4, various known mechanisms that generate a rotational drive force such as a motor can be employed.

Operation during use of the kneader 1 configured as described above will be described.
First, the user inputs a material to be kneaded from the material input port 16. The input material may be appropriately selected from polymer materials such as resin and various materials such as inorganic materials. Thereafter, the inside of the cylinder 5 is heated to a set temperature by the heater 17.

  Thereafter, the screw 6 is rotated at a high speed of, for example, about 1000 to 1500 rotations per minute (rpm). Then, among the materials in the kneader 1, the material located between the outer peripheral surface of the main body 8 of the screw 6 and the inner peripheral surface of the intermediate portion 5 a of the cylinder 5 is crushed by the screw 6 or the material of the heater 17. While being melted by heat, it is pushed by the projection 8A of the main body 8 and moves to the tip side.

  The moved material enters the distal end side in the cylinder 5, then enters the circulation path 10, is again sent to the proximal end side of the main body 8, passes through the discharge hole 11, and again returns to the outer peripheral surface side of the screw 6. Circulate. The material is kneaded by repeating the circulation. During the kneading, the shear heat generated by the rotation of the screw 6 and the cooling effect of the refrigerant flowing in the cooling pipe 13 are substantially balanced, and the temperature in the cylinder is kept substantially constant, but the temperature of the material is a predetermined temperature. When it becomes lower, the control unit controls to close a valve (not shown) provided at the inflow port 14 to stop the supply of the refrigerant.

  When the kneading is completed, the material 17 is taken out, the heater 17 is stopped, and the cylinder 5 is cooled by the refrigerant. Since the cooling pipe 13 is disposed outside the cylinder 5, the wall surface of the cylinder 5 and the embedded heater 17 are efficiently cooled, but the screw 6 inserted into the cylinder 5 is not directly cooled by the refrigerant. Therefore, the screw 6 is not excessively cooled.

  When kneading is continued, the material is charged again from the material charging port 16 and the cylinder 5 is heated. At this time, the screw 6 is not cooled excessively, so that the cylinder can reach the desired set temperature in a short time. Heated.

  In the kneader 1 of the present embodiment, the cooling pipe 13 through which the refrigerant flows is provided around the cylinder 5, so that the screw 6 is not excessively cooled when the cylinder 5 is cooled. Therefore, when the kneading operation is continued several times, the lead time required for cooling and reheating the cylinder 5 between each kneading operation can be shortened, and the total efficiency of the kneading operation can be remarkably improved.

Next, a kneader according to a second embodiment of the present invention will be described with reference to FIG. 2, FIG. 6, and FIG. The difference between the kneading machine 21 of the present embodiment and the kneading machine 1 of the first embodiment is the shape of the cooling pipe.
In addition, about each structure already mentioned in the said 1st Embodiment, the same code | symbol is attached | subjected and the overlapping description is abbreviate | omitted.

  FIG. 6 is an exploded view of the cooling unit 22 of the kneader 21. The cooling duct 23 formed between the exterior member 12 and the cylinder 5 is separated from the first duct 23A on the distal end side and the proximal end side by a partition wall 24 that intersects the central axis 19 (see FIG. 2) of the cylinder 5. The second pipe 23B is divided. Each of the pipelines 23A and 23B has independent inlets 25A and 25B and outlets 26A and 26B, and is configured not to communicate with each other. The partition wall 24 may be formed to be orthogonal to the central axis 19.

  FIG. 7 is a cross-sectional view of the kneading unit 27 and the cooling unit 22. A plurality of grooves 28 extending in the direction of the central axis 19 of the cylinder 5 are provided on the outer surface of the cylinder 5 in the vicinity where the heater 17 is embedded. The refrigerant can enter the groove 28 and functions as an auxiliary conduit communicating with the cooling conduit 23. The amount of refrigerant flowing in the vicinity of the heater 17 is increased by the groove 28, and the contact area between the refrigerant and the wall surface of the cylinder 5 is increased within a predetermined value from the heater 17, for example, within 1 centimeter (cm).

Also in the kneading machine 21 of this embodiment, the same effect as the above-mentioned kneading machine 1 can be acquired.
Further, since the groove 28 functioning as an auxiliary conduit is provided on the outer surface of the cylinder 5, more refrigerant flows near the heater 17 and the heater 17 is quickly cooled. Therefore, it is possible to further reduce the lead time when continuously kneading.

Furthermore, the cooling pipe 23 is divided by the partition wall 24 into the first pipe line 23A and the second pipe line 23B that do not communicate with each other. The cooling conditions can be changed between the first pipe line 23A and the second pipe line 24A, and finer temperature adjustment can be performed.
For example, when the inner cavity of the tip side of the cylinder 5 is set narrow so that the kneading is sufficiently performed, when the tip side is cooled under the same conditions as the base end side, the viscosity increases due to the material being cooled too much, Circulation through the circulation path 10 may not be performed smoothly. In such a case, the temperature setting in the cylinder 5 can be adjusted efficiently without affecting the material circulation by making the cooling setting of the first pipe line 23A weaker than the cooling setting of the second pipe line 23B. it can.

In addition, about the change of cooling setting, the temperature and material of a refrigerant | coolant may be changed and the flow volume of a refrigerant | coolant may be changed. Further, these may be combined as appropriate to change the cooling setting.
Further, in the present embodiment, an example in which the partition wall 24 and the groove 28 as the auxiliary pipe line are provided in the cooling pipe line is shown, but even when only one of them is provided, there is a certain effect, It may be configured as follows.

  The kneaders of the respective embodiments described above will be further described using Examples 1 and 2 corresponding to the kneader 1 and the kneader 21 and comparative examples.

Example 1
As a material to be kneaded, polycarbonate and polyethylene granules were prepared at a ratio of 1: 1, and kneading was performed by rotating the screw 6 at 1500 rpm. As a refrigerant, water at 25 ° C. was used, and was allowed to flow through the cooling line 13 at 5 liters per minute. The temperature of the material during kneading was set to 230 ° C., and control was performed to stop the flow of the refrigerant by closing the valve when the detected value of the sensor 18 was less than 230 ° C.

(Example 2)
In the second embodiment, a partition wall 24 is formed at a position 6 cm from the front end side of the cylinder 5 of the cooling pipe 23, and a groove having a depth of 5 millimeters (mm) is formed as an auxiliary pipe on the outer wall near the heater 17 of the cylinder 5. 28 were formed at two locations for each heater so as to be substantially orthogonal to the outer wall surface of the cylinder 5.
Of the cooling pipe 23 divided by the partition wall 24, 25 ° C. water (first refrigerant) is allowed to flow at 1 liter per minute as the refrigerant through the first pipe 23 </ b> A on the distal end side of the cylinder 5. In the second pipe 23B, 10 ° C. water (second refrigerant) was flowed at a rate of 4 liters per minute as a refrigerant. The material to be kneaded, the number of rotations of the screw, the set temperature of the material being kneaded, and the control mode by the sensor 18 were the same as in Example 1.

(Comparative example)
As the kneading machine of the comparative example, a conventional kneading machine in which a cooling pipe through which a refrigerant flows is formed inside the screw 6 was used. Other conditions were the same as in Example 1.

  Using the kneaders of Examples 1 and 2 and the comparative example, four continuous kneading operations were performed. Between each kneading operation, the inside of the cylinder was once cooled, and then a new material was added. After reheating to the set temperature, the subsequent kneading operation was started. The lead time from the end of the kneading operation to the start of the next kneading operation was defined as the temperature control time. The results are shown in FIG.

  As shown in FIG. 8, regarding the temperature of the resin material before and after processing in each kneading operation, there was no significant difference between each of Examples 1 and 2 and the comparative example, and generally good temperature adjustment was performed. There was no significant difference in the quality of the kneaded resin.

However, looking at the temperature adjustment time between each kneading operation, the temperature adjustment times of the three times in the comparative example took about 8 minutes, respectively, whereas in Example 1 and Example 2, about 3 minutes and about 3 minutes respectively. The temperature adjustment was completed in 2.5 minutes, and the lead time was significantly shortened. As a result, the total time required for the four kneading operations was about 45 minutes in the comparative example, while about 29 minutes in Example 1 and about 27.5 minutes even shorter in Example 2, both. The total time could be greatly reduced compared to the comparative example.
The longer temperature adjustment time in the comparative example was presumed to be due to the fact that the screw was cooled excessively and it took a long time to reheat because the screw was cooled excessively.

Although the embodiments of the present invention have been described above, the technical scope of the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.
For example, in the above-described second embodiment, the example in which the auxiliary conduit is formed by providing the groove 28 on the outer surface of the cylinder 5 has been described. Instead, an auxiliary conduit having a substantially donut-shaped cross section is provided. Alternatively, the heater may be provided inside the wall surface of the cylinder 5 so as to surround the embedded heater in the circumferential direction. Further, the cooling pipe line may be divided into three or more regions by providing two or more partition walls.

1, 21 Circulating kneader 5 Cylinder 6 Screw 10 Circulating path 13, 23 Cooling line 17 Heater (heating mechanism)
23A 1st pipe line (1st field)
23B Second pipeline (second region)
24 Bulkhead

Claims (3)

A circulating kneading machine for kneading the material put into the cylinder using a screw having a circulation path inside,
A heating mechanism embedded in the wall surface of the cylinder to heat the material in the cylinder;
A cooling pipe provided around the cylinder for cooling the material and the heating mechanism by flowing a refrigerant;
An auxiliary pipe that is provided on the wall surface of the cylinder and increases a contact area between the wall surface and the refrigerant;
A circulation type kneader characterized by comprising:   2. The circulating kneader according to claim 1, wherein the cooling pipe is divided into a first region and a second region so as not to communicate with each other by a partition intersecting with a central axis of the cylinder. .   The first refrigerant is flowed through the first region, and a second refrigerant that is different from the first refrigerant in at least one of temperature, flow rate, and material is flowed through the second region. The circulating kneader described in 1.

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