JP2003071907A - Twin-screw kneading extruder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance quality by performing the smooth extrusion of a resin by raising the filling ratio of the resin by making the diameter of the second screw of an extrusion flight part smaller than that of the first screw of a transport part and a kneading part. SOLUTION: In the twin-screw kneading extruder constituted by arranging two screws (3 and 4) in a cylinder in a rotatable manner and having the transport part (5), the kneading part (6), a kneading degree adjusting part (7) and an extrusion part (8) all of which are successively arranged from an upstream side to a downstream side, the diameter (D1) of the first screw of the transport part (5) and the kneading part (6) is made smaller than the diameter (D2) of the second screw of the extrusion part (8) and the kneading degree adjusting part (7) is positioned between the kneading part (6) and the extrusion part (8).

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a twin-screw kneading extruder, and more particularly, to a first screw diameter on the upstream side of a kneading degree adjusting section and a downstream side thereof. The present invention relates to a new improvement for increasing the filling rate of the resin in the extruded portion by making the second screw diameter on the side smaller than that, and for more efficiently and stably conveying the resin. 2. Description of the Related Art In general, a synthetic resin raw material produced by a synthesizing apparatus is often supplied to a large-capacity twin-screw kneading extruder in order to homogenize and improve the properties of the synthetic resin. Is performed. A conventionally used twin-screw kneading extruder is shown in a front sectional view of FIG. 2 and a sectional view of FIG. That is, in FIGS. 2 and 3, what is indicated by reference numeral 1 is a twin-screw kneading extruder.
Is constituted by a long cylindrical cylinder 2 and two screws 3 and 4 rotatably arranged in the cylinder 2. The twin-screw kneading extruder 1 includes at least a transport unit 5, a kneading unit 6, a kneading degree adjusting unit 7, and an extruding unit 8 in order from the upstream side to the downstream side. [0003] The cylinder 2 has a through-hole 9 in which the two screws 2 and 3 are rotatably arranged.
On the upstream side, a raw material supply port 10 penetrating through the wall from above to the through hole 9 is formed, and on the downstream side, a raw material discharge port 11 is formed penetrating through the wall from the through hole 9 to one side surface. ing. The cylinder 2 is configured so that the synthetic resin material flowing in the through-hole 9 can be maintained at a predetermined temperature. The screws 2 and 3 in the through hole 9 of the cylinder 2 are arranged so as to be rotatable in the same direction or different directions in a meshing state or a non-meshing state, and both ends are rotated by bearings 12 and 13. It is freely supported. The screws 2 and 3 are sequentially composed of a transport flight section 20, a kneading rotor section 21, a ring section 22, and an extrusion flight section 23 in order from the upstream side to the downstream side. The transport flight section 20, the kneading rotor section 21, and the extrusion flight section 23 have the same screw diameter. A granulating device 33 is connected to a side surface of the raw material discharge port 11 of the cylinder 2 via a diverter valve 30, a gear pump 31 and a die 32. Next, the operation will be described. First, the cylinder 2 is controlled to a predetermined set temperature, and each of the screws 3, 4
While the is rotated, the powdery or flake-shaped synthetic resin raw material is continuously and quantitatively supplied from the raw material supply port 10 into the through hole 9. The synthetic resin material flows through the transport section 5 while being heated by the transport action of the transport flight section 20 of the rotating screws 2 and 3, and reaches the kneading section 6. In the kneading section 6, the synthetic resin raw material is melt-kneaded by the heating from the cylinder 2 and the kneading action of the rotating kneading section 6. Also, by adjusting the flow cross-sectional area in the downstream-side kneading degree adjusting section 7 to adjust the flow resistance, the residence time of the synthetic resin raw material in the kneading section 6 is adjusted, the kneading degree is adjusted, and the synthetic resin raw material is adjusted. The desired homogenization and modification of [0005] The synthetic resin raw material in a molten state that has passed through the kneading degree adjusting section 7 flows through an extruding section 8 and is extruded from a raw material discharge port 11. The synthetic resin raw material extruded from the raw material discharge port 11 is sent to a gear pump 31 via a diverter valve 30, pressurized by the gear pump 31, extruded to a granulating device 33 via a die 32, and granulated into pellets. Processed. [0006] The conventional twin-screw kneading extruder has the following problems because it is configured as described above. That is, since the screw diameter of the screw is the same from upstream to downstream and the flight height is the same, the extrusion capacity is low in the extrusion flight section, and it is difficult to supply it to the gear pump in a stable manner. This tendency is conspicuous when is high.
This phenomenon further affects the granulating apparatus via the gear pump, making it impossible to perform stable and quantitative granulation, resulting in a decrease in quality. SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and in particular, a first upstream side of a kneading degree adjusting section.
By making the second screw diameter downstream of the screw diameter smaller than the screw diameter, the filling rate of the resin in the extruding section is increased, and the resin is conveyed more efficiently and stably. An object of the present invention is to provide a shaft screw type kneading extruder. [0008] In the twin screw kneading extruder according to the present invention, two screws are rotatably disposed in a cylinder, and are sequentially transported from an upstream side to a downstream side. Part, a kneading part, a kneading degree adjusting part and a twin-screw kneading extruder in which an extruding part is formed, wherein the second screw diameter of the extruding part is smaller than the first screw diameter of the transport part and the kneading part, The kneading degree adjusting section is configured to be located between the kneading section and the extruding section. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a twin-screw kneading extruder according to the present invention will be described below in detail with reference to the drawings. FIG. 1 is a front sectional view of a twin-screw kneading extruder according to the present invention. Parts that are the same as or equivalent to those in the conventional example will be described using the same reference numerals. In FIG.
Is a twin-screw kneading extruder. The twin-screw kneading extruder 1 has a long cylindrical cylinder 2 and two cylinders 2 rotatably arranged in the cylinder 2. It is composed of screws 3 and 4. The twin-screw kneading extruder 1 includes at least a transport unit 5, a kneading unit 6, a kneading degree adjusting unit 7, and an extruding unit 8 in order from the upstream side to the downstream side. The cylinder 2 has a through hole 9 in which the two screws 3 and 4 are rotatably arranged.
An upstream hole 30 upstream of the kneading degree adjusting section 7 and a downstream hole 31 downstream of the kneading degree adjusting section 7 are formed in the through hole 9. The downstream hole 31 has a smaller diameter than the upstream hole 30. Therefore, each of the screws 3 and 4 located in the downstream hole 31 with respect to the first screw diameter D1 which is the flight outer diameter of the transport portion 5 and the kneading portion 6 of each screw 3 and 4 located in the upstream hole 30. The second screw diameter D2, which is the flight outer diameter of the push-out portion 8, is smaller and has a relationship of D1> D2. A raw material supply port 10 penetrating through the wall from above is formed on the upstream side of the cylinder 2, and a raw material discharge port 11 is formed on the downstream side through the wall surface from the through hole 9. The cylinder 2 is configured so that the synthetic resin material flowing in the through-hole 9 can be heated to a predetermined temperature. The screws 3, 4 arranged in the through hole 9 of the cylinder 2 are inserted in a meshing state or a non-meshing state so as to be rotatable in the same direction or in different directions. It is rotatably supported by 12 and 13. The screws 3 and 4 correspond to the respective components of the twin-screw kneading extruder 1, and sequentially from the upstream side to the downstream side, the transport flight section 20, the kneading rotor section 21, and the kneading degree adjustment. It is composed of a ring part 7 and an extrusion flight part 23. Furthermore, the first screw diameter D1 indicating the outer diameter of the flight of the transport flight section 20 and the kneading rotor section 21, that is, the transport section 5 and the kneading section 6, is configured to have the same outer diameter.
3, the second screw diameter D which is the outer diameter of the push-out portion 8
2 has a smaller diameter than the first screw diameter D1. On the downstream side of the cylinder 2 where the raw material discharge port 11 is opened, a granulating device 33 is provided via a diverter valve 30, a gear pump 31 and a die 32 shown in FIG.
Are connected. Here, detailed description of FIG. 3 is omitted. Next, the operation will be described. First, the cylinder 2 is controlled to a predetermined set temperature, and each of the screws 3, 4
In a state where is rotated, the powdery or flake-shaped synthetic resin raw material is continuously and quantitatively supplied from the raw material supply port 10 into the upstream hole 30. The synthetic resin material flows through the transport section 5 while being heated from the cylinder 2 by the transport action of the rotating screws 3 and 4, that is, the transport flight section 20, and reaches the kneading section 6. In the kneading section 6, the synthetic resin material is heated by the cylinder 2 and rotated by the kneading rotor section 2.
The mixture is melt-kneaded by the kneading action with 1. Also, by adjusting the flow cross-sectional area in the downstream kneading degree adjusting section 7 to adjust the flow resistance, the residence time of the synthetic resin raw material in the kneading section 6 is adjusted, the kneading degree is adjusted, and the synthetic resin raw material is adjusted. The desired homogenization and modification take place. The synthetic resin raw material in the molten state, which stays in the kneading section 6 for a predetermined time and passes through the kneading degree adjusting section 7, is heated from the cylinder 2 to a predetermined temperature while rotating the rotating screws 3, 4, ie, the extrusion flight section. Due to the transport action of 20, the fluid flows through the extruding section 8 and is extruded from the raw material discharge port 11. The second screw diameter D2 of the extrusion flight section 23 is configured to be smaller than the first screw diameter D1 of the transportation flight section 20, and the cross-sectional area of the synthetic resin material in the extrusion section 8 is smaller than that in the transportation section 5. As a result, the synthetic resin raw material in the molten state flows through the extruding section 8 in a state where the filling rate is increased, and is continuously and quantitatively extruded from the raw material discharge port 10. The synthetic resin raw material extruded from the raw material discharge port 13 is supplied to a gear pump 31 through a diverter valve 30.
Then, the pressure is increased by a gear pump 31, extruded through a die 32 to a granulating device 33, and processed into pellets. The granulating device shown in FIG. 3 and the like are also configured in the same manner as described above in the present invention, and thus redundant description is omitted and FIG. 3 is also used. The twin screw kneading extruder according to the present invention is constructed as described above, so that the following effects can be obtained. That is, the second screw diameter of the screw in the extruding section is smaller than the first screw diameter of the screw in the transport section and the kneading section, and the cross-sectional area of the flow passage is smaller than that of the transport section. Fill rate rises and flows well,
Quality deterioration can be prevented. In addition, the extrusion of the resin in the extruder became smooth, and a stable granulation operation became possible. In addition, smooth extrusion of resin has resulted in production of high-quality pellets with uniform particle sizes. In addition, since the synthetic resin raw material is filled and flows in the extruding section, the outflow from the kneading degree adjusting section on the upstream side is suppressed, and flow resistance is obtained, and the function of the kneading degree adjusting section can be reinforced and improved. Was.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front sectional view of a twin-screw kneading extruder according to the present invention. FIG. 2 is a front sectional view of a conventional twin-screw kneading extruder. FIG. 3 is a sectional view taken along the line AA in FIG. 2; DESCRIPTION OF SYMBOLS 1 Twin-screw kneading extruder 2 Cylinder 3, 4 Screw 5 Transport section 6 Kneading section 7 Kneading degree adjusting section 8 Extruding section 9 Through-holes 12, 13 Bearing 20 Transport flight section 21 Kneading rotor section 22 Ring part 23 Extrusion flight part 30 Upstream hole 31 Downstream hole D1 First screw diameter D2 Second screw diameter

Claims (1)

[Claim 1] Two screws (3, 4) in a cylinder (2)
Are rotatably arranged, and sequentially from the upstream side to the downstream side, a twin-screw screw formed with a transport section (5), a kneading section (6), a kneading degree adjusting section (7), and an extruding section (8). In the kneading extruder, the first screw diameter (D) of the transport section (5) and the kneading section (6)
The second screw diameter (D2) of the extruding section (8) is smaller than 1), and the kneading degree adjusting section (7) includes the kneading section (6) and the extruding section (8).
And a twin-screw kneading extruder.