JP2004066705A - Molten-resin temperature control method for screw type extruder, and screw type extruder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect the temperature of a screw by a temperature measuring body for the screw; to control the temperature of a synthetic resin raw material with high accuracy by controlling the temperatures of the screw, a cylinder and the like; and to perform stable operations. <P>SOLUTION: In a molten-resin temperature control method for a screw type extruder, the temperature of the synthetic resin raw material after mixing at the tip part of the cylinder (15) is measured, and cooling water is passed for cooling through the shaft core part of the screw (14); and a temperature near a surface in the screw (14) is measured, and the quantity of the cooling water passing through the inside of the screw (14) is controlled. Thus, the temperature of the synthetic raw material is controlled. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for controlling the temperature of a molten resin of a screw-type extruder and a screw-type extruder, and more particularly to a novel improvement for controlling the temperature of a screw with a temperature sensor for a screw and improving product quality. .
[0002]
[Prior art]
Conventionally, the configuration shown in FIGS. 4 to 8 has been employed as a screw-type extruder for a synthetic resin material.
That is, in FIG. 4, what is indicated by reference numeral 100 is a screw-type extruder. The screw-type extruder 100 can rotate the drive motor 12, the speed reducer 13, and the screw 14 from one end of the gantry 11. The cylinders 15 are sequentially connected and arranged. In FIG. 4, one screw 14 is shown, but two screws 14 may be arranged in parallel. In addition, a control device 20 is provided adjacent to the gantry 11, and a temperature controller 23 connected to a cylinder temperature sensor 21 and an electromagnetic valve 22 described below is incorporated.
[0003]
In the cylinder 15, a connecting cylinder 23, a raw material supply cylinder 25 having a hopper 24, a plurality of temperature control cylinders 26, and a tip cylinder 27 are connected from the reduction gear 13 side by arranging through-holes in a straight line. The connection cylinder 23 has a through hole (not shown) for a pipe connected to a rotary joint 50 to be described later formed through the wall. Each of the raw material supply cylinder 25 and the temperature adjustment cylinder 26 has a water cooling cylinder jacket 31 formed inside the wall. The water cooling jacket 31 is connected to the cooling water unit 16 by a supply pipe 32 and a return pipe 33. Solenoid valves 22 are provided in branch pipes of the supply pipe 32 to the respective temperature control cylinders 26. The temperature control cylinder 26 is provided with a cylinder heater 40 on the outer periphery. The solenoid valve 22 and the cylinder heater 40 are connected to the control device 20. The temperature adjusting cylinder 26 and the tip cylinder 27 are provided with cylinder temperature sensors 21 for measuring the temperature near the inner wall surface in the walls. Further, the tip cylinder 27 is provided with a resin temperature sensor 28 that penetrates the wall and projects into the inner hole.
[0004]
In FIG. 5, the screw 14 includes a screw shaft 41, a plurality of and plural types of screw segments 42, and a tightening nut 42a. The screw shaft 41 is inserted into the cylinder 15 and has a substantially regular polygonal cross section perpendicular to the axis.
[0005]
In FIG. 6, a cooling water hole 41a is formed in the screw shaft 41 of the screw 30 from the rear end of the speed reducer 13 side to the front end side. In the screw shaft 41, a water supply hole 44 penetrating from the cooling water hole 41a to the outer periphery and a drainage hole 45 adjacent to the water supply hole 44 are formed in two axially close positions. A discharge hole 43 is coaxially arranged on the outer periphery of the cooling water hole 41a, and the discharge hole 43 communicates with a drain hole 45.
[0006]
The outer periphery of the screw shaft 14 where the water supply hole 44 and the drain hole 45 are located is relatively rotatable in a watertight state, that is, FIG. 8 for supplying cooling water to the screw 14 that is driven to rotate during operation. The rotary joint 50 is connected. The rotary joint 50 supplies and drains the cooling water even during the rotation of the screw 14.
[0007]
The screw-type extruder 100 configured as described above operates as follows. First, the cylinder heater 40 of the cylinder 15 is energized to raise the temperature. Cooling water is supplied from the cooling water unit 16 to each of the cylinder jackets 31, and the cylinder heaters 40 and the solenoid valves 22 are adjusted by the control device 20 as necessary. 26 are controlled so as to reach respective predetermined temperatures. Next, the drive motor 12 is started, the screw 14 is rotationally driven via the speed reducer 13, and the synthetic resin material is supplied from the hopper 24 to the inner hole of the material supply cylinder 25. The synthetic resin raw material is sequentially transported in the tip direction by the transport action of the rotating screw 14. During this transportation, the synthetic resin raw material is kneaded and melted by the kneading action of the rotating screw 14 and the heating of the temperature-adjusting cylinder 26 whose temperature has been raised. The synthetic resin material in a molten state, which has reached the tip of the cylinder 15 after the completion of the predetermined kneading, is extruded from the tip cylinder 27 through the die 27a. The unmelted synthetic resin raw material supplied from the hopper 24 is prevented by the gland seal 23a so as not to leak toward the speed reducer 13.
[0008]
Further, at a point in time after the drive motor 12 is started, the cooling water is continuously supplied from the water supply pipe 44a via the rotary joint 50. The cooling water is supplied from the rotary joint 50 to the cooling water hole 41 a through the water supply hole 44 of the screw shaft 41, and then flows back through the discharge hole 43 on the outer periphery of the cooling water hole 41 a, and is rotated from the drain hole 45 of the screw shaft 41. It is discharged outside through the joint 50. That is, the cooling water cools the screw shaft 41 from the inner peripheral surface, and thus cools the screw 14 from the inside, while the cooling water flows backward through the inner peripheral surface of the cooling water hole 41a and the discharge hole 43.
[0009]
Inside the cylinder 15, the synthetic resin raw material generates heat when it is subjected to a shearing action by the screw 14 that is driven to rotate and melts, and the temperature of the synthetic resin raw material may rise to or above a predetermined temperature controlled by each of the temperature control cylinders 26. is there. In response to such an abnormal temperature rise of the synthetic resin raw material, cooling from the inside of the screw 14 and the temperature near the inner wall surface of the temperature adjusting cylinder 26 by the cylinder temperature detector 21 and after kneading by the resin temperature detector 28 are performed. By controlling the cylinder heater 40 and the solenoid valve 22 based on the measurement result of the molten synthetic resin raw material temperature, the temperature during and after kneading of the cylinder 15 is controlled to be a predetermined temperature.
[0010]
[Problems to be solved by the invention]
Since the conventional screw-type extruder and its temperature control method are configured as described above, the following problems exist.
That is, it cannot be said that the synthetic resin raw material is always transported in a state of filling the inside of the cylinder, and the temperature detection accuracy of the synthetic resin raw material is low in the resin temperature detector provided near the inner wall surface in the cylinder wall. Therefore, it is difficult to control the melting temperature of the synthetic resin material with high precision. For example, when kneading a low melting point synthetic resin material such as an EVA resin material or a coating material, it is very difficult to control the temperature in a low temperature region. is there. As a result, stable operation could not be continued, and it was difficult to ensure uniform product quality. In addition, although cooling water is steadily passed through the screw shaft to suppress temperature rise due to shear heat generation of the synthetic resin raw material, the temperature measurement and temperature control of the screw shaft itself are not performed.
[0011]
The present invention has been made in order to solve the above-described problems, and in particular, detects the temperature of the screw with a screw temperature detector provided on the screw to control the temperature of the screw, and to reduce the amount of the synthetic resin raw material. An object of the present invention is to provide a method of controlling the temperature of a molten resin of a screw-type extruder and a screw-type extruder capable of improving product quality by temperature control.
[0012]
[Means for Solving the Problems]
The method for controlling the temperature of a molten resin of a screw-type extruder according to the present invention comprises a long cylindrical cylinder and a screw which is rotatably inserted into the cylinder and through which cooling water can be passed and discharged. Using a screw-type extruder for melting and kneading the raw materials, controlling the flow rate of the cooling water in the screw by a detected temperature signal detected by a screw temperature detector provided near the surface of the screw, A method of controlling the temperature of the raw material, and cooling by passing cooling water through the wall of the cylinder, heating by a cylinder heater provided on the outer periphery of the cylinder, and the temperature of the inner wall of the cylinder or its vicinity. And controlling the temperature of the cylinder based on the temperature to control the temperature of the synthetic resin raw material. Further, the screw type extruder according to the present invention melts and kneads the synthetic resin raw material with a long cylindrical cylinder and a screw which is rotatably inserted into the cylinder and through which cooling water can be passed and discharged. In a screw-type extruder, a screw temperature detector provided near the surface of the screw is provided, and a cylinder jacket and a cylinder heater provided in the cylinder are provided, and the inner wall of the cylinder or the inner wall thereof is provided. And a resin thermometer provided so as to protrude therefrom.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of a method for controlling a molten resin temperature of a screw-type extruder and a screw-type extruder according to the present invention will be described with reference to the drawings. Note that the same or equivalent parts as those in the conventional example are denoted by the same reference numerals, and the description thereof will be omitted.
The different parts are a structure having a cooling water supply shaft structure in the screw 14 and a screw temperature measuring element for detecting the temperature of the screw 14.
[0014]
In FIG. 1, the screw shaft 41 of the screw 14 has a non-penetrating cooling water hole 41a formed in the shaft core portion from the rear end on the drive motor 12 side to the front end side. The cooling water holes 41 a are formed coaxially with double and triple cooling water holes 41 aA and 41 aB, which are different from the conventional cooling water holes 41 a, and these are communicated with the discharge holes 43. These cooling water holes 41a to 41aB are connected to the plurality of water supply holes 44 and the respective solenoid valves 44B from the rotary joint 50, and each of the cooling water holes 41a is opened and closed individually by the control device 20 by the control device 20. , 41aA and 41aB can be selectively controlled.
The cooling water discharged from each of the cooling water holes 41a, 41aA, 41aB is collected or discharged from the common discharge hole 43 through the drain hole 45 via the rotary joint 50.
[0015]
A plurality of screw temperature detectors 200, 200a, 200b (arbitrary numbers) are disposed on the screw shaft 41 of the screw 14 near the surface thereof, and each of the screw temperature detectors 200, 200a, 200b is It is arranged at different length positions along the axial direction, and is configured so that temperature detection at different length positions can be performed.
[0016]
The screw temperature detectors 200, 200a, and 200b are connected to a transmission head 202 provided at an end of the screw shaft 41 via a wiring 201, and each of the screw temperature detectors 200, 200a, and 200b is connected. The detected temperature signal is transmitted from the transmission head section 202 to the opposed output head section 203 via well-known electromagnetic means or non-contact wireless transmission means such as infrared rays.
[0017]
The detected temperature signals output from the output head unit 203 are input to the temperature controller 23 of the control device 20, and the detected temperature signals are input to the temperature controller 23 in a real-time state while the screw 14 is rotating. can do.
[0018]
Next, the operation will be described. First, at a point in time after the drive motor 12 is started, the cooling water is supplied via the rotary joint 50. The cooling water is sent to the cooling water holes 41a, 41aA, 41aB according to the opening and closing of the solenoid valves 44B, and is collected or discharged from the rotary joint 50 to the outside through the drain hole 45 through the drain hole 43.
[0019]
That is, the cooling water cools the screw 14 heated by the shear heat of the synthetic resin raw material while flowing from the cooling water holes 41a, 41aA, 41aB to the discharge hole 43.
[0020]
During this time, screw temperature measuring elements 200, 200a, and 200b provided at three locations measure the temperature of each position of the screw 14, and each detected temperature signal is transmitted from the transmission head section 202 through the output head section 203 to the temperature controller. 23, the opening and closing of each solenoid valve 44B is controlled, and the screw 14 is controlled to a desired set temperature. That is, by controlling the temperature of the screw 14 from the inside of the screw 14, the temperature of the synthetic resin material transported and kneaded while being in contact with the screw 14 is controlled. Accordingly, the screw-type extruder 100 is controlled by the temperature controller 23 of the control device 20 based on the measurement data of the cylinder temperature detector 21, the resin temperature detector 28, and the screw temperature detectors 200 to 200b. The temperature of the synthetic resin material to be kneaded and melted during and after kneading is maintained in a desired state by controlling the 44B and the cylinder heater 40.
[0021]
【The invention's effect】
Since the molten resin temperature control method and the screw-type extruder of the screw-type extruder according to the present invention are configured as described above, the following effects can be obtained.
(1) A screw in a screw type kneading extruder is provided with screw temperature detectors at a plurality of different positions in the screw shaft in the axial direction, and the temperature near the screw surface is measured, so that the synthetic resin raw material is reduced. Even when the material is transported in a non-full state in the cylinder and is kneaded and melted, the temperature of the synthetic resin material transported and kneaded while contacting the screw can be measured with high accuracy.
(2) A plurality of cooling water holes are formed in the screw shaft of the screw in the screw type extruder, so that the temperature can be finely adjusted and the temperature of the synthetic resin material can be controlled with high precision.
(3) Accordingly, uniform product quality can be easily ensured without stopping the screw and lowering the rotation speed of the screw due to an increase in the temperature of the molten resin.
[Brief description of the drawings]
FIG. 1 is a sectional configuration view showing a main part of a screw-type extruder according to the present invention.
FIG. 2 is a transverse sectional view showing a main part of FIG.
FIG. 3 is a sectional view of the entire length of the screw of FIG. 1;
FIG. 4 is a sectional view showing a conventional screw-type extruder.
FIG. 5 is a sectional view showing the screw of FIG. 1;
FIG. 6 is a cross-sectional configuration diagram illustrating a main part of FIG. 4;
FIG. 7 is a cross-sectional view of a main part of FIG. 6;
FIG. 8 is a detailed configuration diagram showing the rotary joint of FIG. 6;
[Explanation of symbols]
14 Screw 15 Cylinder 20 Controller 21 Cylinder temperature detector 23 Temperature controller 28 Resin temperature detector 31 Cylinder jacket 40 Cylinder heater 41 Screw shaft 41a Cooling water hole 44 Water supply hole 44B Solenoid valve 45 Drain hole 50 Rotary joint 100 Screw type extrusion molding machines 200 to 200b Screw temperature detector 202 Transmission head unit 203 Output head unit

Claims (4)

A screw type that melts and kneads a synthetic resin raw material by a long cylindrical cylinder (15) and a screw (14) inserted rotatably into the cylinder (15) so as to allow cooling water to flow and discharge inside. Using the extruder (100), the flow rate of the cooling water in the screw (14) based on a detected temperature signal detected by a screw temperature detector (200 to 200b) provided near the surface of the screw (14). And controlling the temperature of the synthetic resin raw material by controlling the temperature of the synthetic resin raw material. Cooling water is passed through the wall of the cylinder (15) to cool it, and the cylinder is heated by a cylinder heater (40) provided on the outer periphery of the cylinder (15). 2. The method according to claim 1, wherein the temperature of the cylinder (15) is controlled based on the temperature, and the temperature of the synthetic resin material is controlled. . A screw-type extrusion for melting and kneading a synthetic resin material by means of a long cylinder-shaped cylinder (15) and a screw (14) rotatably inserted into the cylinder (15) and through which cooling water can be passed and discharged. A screw extruder, comprising: a molding machine having a screw thermometer (200 to 200b) provided near a surface of the screw (14). The cylinder (15) includes a cylinder jacket (31) and a cylinder heater (40) provided on the cylinder (15), and an inner wall of the cylinder (15) or a resin temperature detector (28) provided to protrude from the inner wall. The screw-type extruder according to claim 3, characterized in that:

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