JPH0579217B2 - - Google Patents

Description

[Detailed description of the invention] (b) Industrial application fields The present invention relates to a twin screw extruder.

(b) Prior Art Some twin-screw extruders use rings as shown in Japanese Utility Model Application No. 55-45553 for sealing the upstream and downstream sides of the degassing section. Resistance is provided to the flow of the resin by rings provided at different positions on both screws, and in this state, the surface of the resin is renewed and unnecessary gas is removed by exhausting. Further, when the resin and the reaction solution are caused to react in the reaction section, the ring is also provided on the downstream side of the reaction section, thereby controlling the reaction by taking residence time. Reversing screws can also be used instead of rings.

(c) Problems to be solved by the invention As mentioned above, the rings that provide flow path resistance are arranged differently on the left and right screws,
The resin is configured to flow through the gaps between these. The resin that has passed through the gap between the rings is not equally distributed between the two screws, but tends to flow in large quantities toward one of the screws.
For this reason, efficient degassing cannot be performed in the degassing section. Furthermore, it is necessary to change the dimensions of the ring depending on operating conditions such as the type of resin and the rotational speed of the screw. On the other hand, in the case of a reverse-feeding screw, if an attempt is made to improve the degassing effect by increasing the feeding capacity in the reverse-feeding direction, a vent-up phenomenon (a phenomenon in which resin swells up at the vent port) occurs. In any case, it is difficult to precisely set the conditions of the degassing section and the reaction section as desired. In particular, it is not possible to make fine adjustments during operation.

The present invention aims to solve these problems.

(d) Means for Solving the Problems The present invention solves the above problems by providing a plurality of flow path resistance adjusting devices that can precisely control flow path resistance. That is, in the twin-screw extruder according to the present invention, flow path resistance adjusting devices (80 and 81) are provided at a plurality of positions in the axial direction of the barrel 10, and each flow path resistance adjusting device is provided with screws (12 and 13). ) is arranged in the middle of the flight and has a smaller diameter than the outer diameter of the flight (12a and 13a).
and a blocking wall portion (33 and 35) and 2
Connecting passages (39 and 41) provided in the blocking wall so as to communicate the upstream side of the blocking wall of the shaft hole with the downstream side of the blocking wall of the biaxial hole, and the passage cross-sectional area of the connecting passage. controllable valves (43 and 45);
have. Note that the reference numerals in parentheses above indicate corresponding members in the embodiments described later.

(e) Effect The molten raw material on the upstream side of the blocking wall can flow downstream only through the connecting passage. A valve is provided in the connecting passage, and the molten raw material passes through it at a predetermined speed depending on the degree of opening of the valve. Therefore, the flow of the molten raw material can be arbitrarily controlled from a state where the connecting passage is almost completely blocked to a state where the connecting passage is fully opened. Furthermore, the molten raw material can be flowed evenly to the left and right sides of the biaxial hole. Thereby, the retention state of the molten raw material between the two flow path resistance adjusting devices can be adjusted as desired, and the degree of degassing, the degree of reaction, etc. can be adjusted as desired. Moreover, this adjustment work can be performed even during operation.

(f) Example (Example 1) FIG. 1 shows a twin-screw extruder according to the present invention. This twin-screw extruder includes a barrel 10 constructed by connecting a large number of divided barrels, and two screws 12 and 13 inserted into the twin-screw holes of the barrel 10 (in addition,
The screw 13 has a screw (not shown in FIG. 1). This twin-screw extruder is divided into a feeding section 14, a kneading section 16, a kneading degree adjusting section 18, a degassing section 24, a sealing section 26, and a metering and feeding section 28 according to the functions from the upstream side in the flow direction of the raw materials. Ru.

The supply section 14 is provided with a raw material supply port 15, and the degassing section 24 is provided with a vent port 25. Flow path resistance adjusting devices 80 and 81 are provided in the kneading degree adjusting section 18 and the sealing section 26, respectively.

As shown in FIGS. 2 to 5, the flow path resistance adjusting device 80 has blocking walls 33 and 35 provided at the inner diameter of the biaxial hole of the barrel. The blocking walls 33 and 35 are the cylindrical portions 12 of the screws 12 and 13.
It is provided over the entire length of a and 13a.
That is, the entire length of the cylindrical portions 12a and 13a in which no flights are provided is the blocking wall portions 33 and 35.
It fits into the inner diameter of the Therefore, the cylindrical part side end surfaces 12b and 13b of the flights are connected to the blocking wall part 3.
3 and 35 will face each other with a small gap between them. Connecting passages 39 and 41 are provided in the blocking walls 33 and 35 . As shown in FIG. 5, the connection passage 39 connects the upstream side of the blocking wall 33 of the hole on the side where the screw 12 is disposed with the screw 12.
3 is provided so as to be connected to the downstream side of the blocking wall portion 35 of the hole on the side where the hole is placed. On the other hand, the connection passage 41 is
The upstream side of the blocking wall 35 of the hole on the screw 13 placement side is connected to the blocking wall 35 of the hole on the screw 12 placement side.
It is provided so as to be connected to the downstream side of. Valves 43 and 45 are provided in these connecting passages 39 and 41 (see FIG. 4. Although valve 45 is not shown, it is the same as valve 43). valve 43
(and 45) connects the two shaft holes in the state shown in FIG. 4, and when rotated 90 degrees from this state, the connection between the two is cut off. Valves 43 and 45 are
It is rotationally driven by a motor 82 and a gear mechanism 84 shown in FIG. The flow path resistance adjustment device 81 is exactly the same as the flow path resistance adjustment device 80.

Next, the operation of this embodiment will be explained. The raw material introduced into the barrel 10 of the twin-screw extruder from the raw material supply port 15 is moved by the screws 12 and 13 from the upstream side to the downstream side, that is, rightward in FIG. 1. The kneading degree adjusting section 18 restricts the flow of the raw materials, and the kneading section 16 performs the kneading in a predetermined manner. That is, by operating the motor 82 and setting the opening degrees of the connection passages 39 and 41 to a predetermined state by the valves 43 and 45, the amount of movement of the raw material can be adjusted. Connection passages 39 and 41
By reducing the cross-sectional area of the passage in the kneading section 16
is filled with resin, where the resin is subjected to a large shearing action and is melted and kneaded. The degree of kneading of the resin depends on the residence time of the resin in the kneading section 16. The residence time of the resin is adjusted by the opening degree of the connecting passages 39 and 41. Since substantially all of the resin passes through the connecting passages 39 and 41, by adjusting the degree of opening of these, the degree of kneading can be precisely adjusted as desired.

The molten raw material that has passed through the flow path resistance adjusting device 80 is
Next, unnecessary gas is removed in the degassing section 24. That is, unnecessary gas can be removed by exhausting from the vent port 25 while applying a predetermined resistance to the flow of the raw material by the flow path resistance adjusting device 81. In this case, the residence time of the raw material and the filling ratio of the biaxial hole of the barrel can be adjusted as desired by the flow path resistance adjusting device 81 as described above, so that the degassing effect can be enhanced. Further, the flow of resin to the connecting passages 39 and 41 can be equally distributed on the left and right sides. In this way, the flow of the raw material before and after the degassing section 24 can be precisely controlled, so even if the operating conditions such as the raw material and the rotational speed of the screws 12 and 13 are changed, the desired degassing can be easily achieved. The degree can be set. Note that in this embodiment, the valve 43
45 is of the type that adjusts the flow path resistance by rotating, but it may be of a type where the valve stem is configured in the shape of a piston and the flow path resistance is adjusted by moving up and down. You can also do it.

(Second Embodiment) FIG. 6 shows a second embodiment. In this second embodiment, a second degassing section 90 having a vent port 27 is provided downstream of the flow path resistance adjusting device 81 of the first embodiment. This can further enhance the degassing effect.

(Third Embodiment) FIG. 7 shows a third embodiment. In this third embodiment, a reaction section 92 is provided on the downstream side of the flow path resistance adjusting device 80 of the above-described first embodiment. The reaction section 92 is provided with an injection port 94 for injecting a solution for reaction. By adjusting the opening degree of the flow path resistance adjusting device 81, the degree of shearing action for effectively weaving the solution into the resin and the appropriate residence time for causing the solution to react with the resin can be adjusted as desired. I can do it. This allows an appropriate reaction to occur.

(G) Effects of the Invention As explained above, according to the present invention, since a plurality of flow path resistance adjusting devices that can precisely control the flow path resistance are provided, it is possible to precisely adjust the flow of resin. Therefore, the degree of degassing, degree of reaction, etc. can be adjusted as desired. Further, this adjustment work can be performed even during operation.

[Brief explanation of drawings]

Fig. 1 is a diagram showing a twin-screw extruder which is an embodiment of the present invention, Fig. 2 is a diagram showing a flow path resistance adjustment device, and Fig. 3 is a diagram showing a flow path resistance adjusting device.
Figure 2 is a sectional view taken along the - line in Figure 2, Figure 4 is a cross-sectional view along the line -
5 is a perspective view showing the flow path resistance adjusting device, FIG. 6 is a view showing the second embodiment, and FIG. 7 is a view showing the third embodiment. 10...barrel, 12,13...screw,
12a, 13a... Cylindrical part, 18... Kneading degree adjusting part, 33, 35... Blocking wall part, 39, 41...
Connection passage, 43, 45... valve.

Claims (1)

[Claims] 1. In a twin-screw extruder in which two screws are installed in two-shaft holes in a barrel, flow path resistance adjusting devices are provided at a plurality of positions in the axial direction of the barrel, and each flow The road resistance adjustment device is placed in the middle of the flight of the screw and has a cylindrical part with a smaller diameter than the flight outer diameter, and is placed in the axial position of the two-shaft hole corresponding to this cylindrical part and has a small diameter in the cylindrical part of the screw. A blocking wall portion having an inner diameter portion smaller than other portions so as to fit into the gap, and communicating the upstream side of the blocking wall portion of the biaxial hole with the downstream side of the blocking wall portion of the biaxial hole. a connecting passage provided in the blocking wall, and a valve capable of controlling the passage cross-sectional area of the connecting passage;
A twin screw extruder comprising: 2. The blocking wall portion of the flow path resistance adjusting device is provided over a length corresponding to the entire length of the cylindrical portion of the screw, and the blocking wall portion has a portion upstream of the blocking wall portion on one hole side. A first connecting passage that communicates with the downstream side of the blocking wall on the other hole side, and a second connecting passage that communicates the upstream side of the blocking wall with the other hole side with the downstream side of the blocking wall on the one hole side. Claim 1: A connecting passage is provided, and each of the first and second connecting passages is provided with a valve device capable of controlling the cross-sectional area of the passage.
A kneading degree adjusting device for the twin-screw extruder described above. 3. The twin-screw extruder according to claim 1 or 2, wherein the one flow path resistance adjusting device is provided downstream of the kneading section. 4. The twin-screw extruder according to claim 1, 2 or 3, wherein the one flow path resistance adjusting device is provided downstream of the degassing section. 5. The twin-screw extruder according to claim 1, wherein the one flow path resistance adjusting device is provided downstream of the reaction section.