JPH09220756A - Method for controlling emission of resin and production of film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To develop more excellent capacity when the characteristics of a molten resin are changed by the number of rotations of a screw by controlling the number of rotations of the screw or/and resin supply speed of a screw extrusion part on the basis of the signal of a weighing and emitting part to weigh and emit the molten resin. SOLUTION: A weighing and emitting speed Ng is detected on the basis of the detection signal by a number-of-rotation detector 14 and the speed Nf of a resin supply part driving device 3 is calculated,in predetermined relation by a resin supply control part 18 to control the drive device 3 of a supply device and the number of rotations Ns of a screw is calculated in predetermined relation by a screw number-of-rotation control part 17 to control a screw driving device 7. A pressure change over a relatively long period of time is subjected to time processing and the pressure change quantity ΔP2 thereof is converted to screw number-of-rotation change quantity ΔNf by a resin supply machine speed operator 16 and the signal thereof is sent to the resin supply control part 18 to control the resin supply speed Nf of the drive device 3 of the resin supply part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin discharge control method using a screw type extruder and a film manufacturing method using the method. More specifically, the present invention relates to a resin discharge control method that uses an extruder having a resin supply section, a screw extrusion section, and a metering and discharge section, and a film manufacturing method using the method.

[0002]

2. Description of the Related Art The method of operating an extruder equipped with a resin supply section, a screw extrusion section, and a metering / discharging section includes the screw speed control of the extruder, the pressure control of the extruder discharge port, and the supply amount of the resin supply machine. There is a method of controlling (volume, weight).

As a typical example, a method in which the screw rotation speed is controlled to be constant, the resin pressure at the discharge port of the extruder is measured, and the supply amount of the resin feeder is adjusted so that the pressure has a certain value (for example, a special method) (Kaisho No. 50-161553), a method of controlling the resin supply amount and the modifier supply amount by detecting the extruder discharge pressure (Jpn. Pat. Appln. KOKAI Publication No. 1-18330), the extruder discharge pressure is detected, and the screw Control the pressure at the number of revolutions of the motor, and control the supply amount by feeding back the rotation speed detection signal to the resin supply device (Japanese Patent Publication No. 2-50207). The speed of the resin feeder and extruder screw is controlled so that the speed of the metering / discharging device is controlled by operating the number of rotations of the resin feeder and the extruder screw during unsteady conditions such as speed change. How machine discharge pressure to control the metering discharge speed to be constant (KOKOKU 6-55415 JP)
and so on.

[0004]

SUMMARY OF THE INVENTION In addition to the conventional stable operation method of an extruder during constant speed operation, operation method in a transient state until constant discharge such as resin change or start-up of production, the present invention is added. Devolatilizing, melting, kneading, mixing the extruder screw,
It has been reached as a result of earnest research to more effectively exert functions such as dispersion, and the problem of the present invention is more excellent particularly when the characteristics of the molten resin change depending on the rotation speed of the extruder screw. An object of the present invention is to provide an operation control method of an extrusion device capable of exhibiting performance.

[0005]

In order to solve the above-mentioned problems, the resin discharge control method of the present invention uses an extruder having a resin supply section, a screw extrusion section, and a metering discharge section, and Based on the signal, the screw rotation speed of the screw extrusion unit is controlled and / or the supply speed of the resin supply unit is controlled, and the molten resin is metered and discharged.

More specifically, the change in pressure of the molten resin between the screw extruding section and the metering and discharging section is detected, the change is time-processed, and the screw rotation speed of the screw extruding section is determined based on the short-term change signal. It is a method of controlling and / or controlling the supply speed of the resin supply unit based on the long-term change signal.

By using such a resin discharge control method,
For example, the discharged molten resin can be formed into a film, which makes it possible to form a film having extremely uniform physical properties and less variation in thickness.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. FIG.
1 illustrates a resin discharge control device according to an embodiment of the present invention. The resin, for example, a thermoplastic resin, supplied to the resin supply unit 1 is supplied to the screw extrusion unit 6 by the supply device 2 and is used for one or more of devolatilization, melting, kneading, mixing, dispersion of the screw 5. A desired molten resin is supplied to the connecting pipe 9 by the action, and is metered and discharged by the meter 11 of the metering and discharging unit 12.

The supply device 2 of the resin supply unit can measure the supply amount of the resin by volume and / or weight.
That is, in the case of supplying by the capacity, the speed of the drive device 3 of the supply device is controlled in accordance with the relationship between the capacity of the resin and the supply speed according to a predetermined relational expression. On the other hand, in the case of supplying by weight, the amount of resin supplied is detected by the weight measuring device 4, the deceleration speed is calculated, and the drive device 3 is controlled based on a predetermined relational expression. The supply amount may be controlled by using both the volume and the weight.

The supplied resin is supplied to the screw extruding section 6 of the extruding device, and is made into a molten resin by one or more functions such as devolatilization, melting, kneading, mixing, and dispersion, and is connected to the connecting pipe 9. Sent. In the screw extrusion unit 6,
Since the resin is extruded forward without completely filling the space between the screw 5 and the barrel 5 ', the extrusion speed of the resin is not uniquely determined only by the screw rotation speed. Further, the screw rotation speed is controlled by the driving device 7.

The melted resin is metered and discharged by the metering device 11 of the metering and discharging section 12 (here, a metering device using a gear pump using a gear is shown, but a device using a screw or the like may be used). However, the discharge speed of the metering device is controlled by the drive device 13.

The control of the extrusion device of the present invention is performed by detecting the rotation speed of the driving device 13 of the metering and discharging device by the rotation speed detector 14. Further, the pressure of the molten resin is detected by the pressure detector 10 provided in the connecting pipe 9. Pressure detector 1
The temperature of the molten resin may be controlled by combining a temperature detector of the molten resin with 0. In this case, the temperature of the resin to be supplied, the temperature of the screw extruder, the screw rotation speed, and the like can be controlled, but since the temperature of the screw extruder can be controlled, it can be directly controlled. preferable.

In the present embodiment, the metering and discharging speed Ng is detected by the detection signal from the rotation speed detector 14, and the speed Nf of the resin supply section drive device 3 is calculated by the resin supply control section 18 in a predetermined relationship. The drive device 3 of the supply device is controlled, the screw rotation speed control unit 17 calculates the screw rotation speed Ns in a predetermined relationship, and the screw drive device 7 is controlled. By doing so, it becomes possible to balance the physical quantity between the metering and discharging speed and the resin supplying speed, and it is possible to operate at the screw rotation speed most suitable for resin melting.

Generally, in an extruder, the screw performance can be brought out by setting the ratio Q / N between the discharge amount Q and the screw rotation speed N around a certain value or by keeping the screw rotation speed constant. Although designed, in the present invention, the screw can further be used for producing a film or the like by making the characteristics of the molten resin, additives and the like the most preferable properties.

Further, in the present embodiment, the pressure of the molten resin in the connecting pipe 9 is detected, and the change thereof is time-processed, and the screw rotation speed calculator 1 is used for a relatively short time pressure change.
5, the pressure change amount ΔP1 is converted into a screw rotation speed change amount ΔNs, and the signal is sent to the screw extruder control unit 17 to control the screw rotation speed Ns of the screw driving device 7. Further, for a pressure change for a relatively long period, the time-processed change is treated as a resin feeder speed calculator 1
6, the pressure change amount ΔP2 is converted into the screw rotation speed change amount ΔNf, and the signal is converted into a signal.
To control the resin supply speed Nf of the drive device 3 of the resin supply unit. By doing so, it is possible to suppress the fluctuation of the molten resin pressure that occurs in a short period of time and to send the resin to the metering and discharging section in a more stable state, and to measure the metering and discharging speed accumulated over a long period of time and the resin supply speed. Since it is possible to correct the deviation of the physical quantity balance, it is possible to stably operate the extruder continuously for a long period of time.

Furthermore, in an extruder having a vent function, it is possible to operate the extruder stably while preventing vent-up trouble.

The present invention will be described in more detail based on the following examples. The evaluation method was as follows. (1) Particle dispersibility A molten resin was extruded from a wide-width die onto a rotating cooling body to obtain an unstretched film, which was subjected to surface treatment by plasma etching and then observed with a scanning electron microscope. Convert to and obtain the average and variance.

(2) Intrinsic viscosity Measured at 25 ° C. with orthochlorophenol.

Example 1 The primary particle size was 0.02 μm and the average particle size was 0.8 μm.
Polyester having an intrinsic viscosity of 0.61 containing 0.15% by weight of agglomerated silica particles of m and 0.15% by weight of spherical silica particles having an average particle size of 0.4 μm, and Ktron manufactured by Kawata as a resin supply device, A twin-screw vent extruder TEX manufactured by Japan Steel Works, Ltd. is used as an extruder, and a gear pump manufactured by Kawasaki Heavy Industries, Ltd. is used as a metering / discharging device. The film was discharged and cooled to obtain an unstretched film.

The number of revolutions of the metering and discharging device and the number of revolutions of the resin supplying device are shown by b (b ') in FIG.
Due to the relationship as shown in (a ′), a change within 3 seconds as a short-term fluctuation of the molten resin pressure fluctuation is set to 2 as the screw rotation speed.
The change over a minute is controlled by adding or subtracting the change of the rotation speed of the resin supply device to the calculation of the signal of the metering and discharging device. Observing the state of particles in the obtained unstretched film,
And the intrinsic viscosity of the film was measured and shown in Table 1.
In the discharge range from low speed to high speed of the metering and discharging device,
Good results have been obtained. Furthermore, the metering and discharging device was accelerated from low speed to high speed, and then it was operated for a long time on the high discharging side, but there was no trouble such as venting up.

Comparative Example 1 The apparatus of Example 1 was used as the extruder, and the pressure of the molten resin was detected to control the number of rotations of the resin supply device while the number of rotations of the extruder screw was kept constant. The properties of the obtained unstretched film are shown in Table 1. The metering and discharging device was further accelerated from low speed to high speed, but it took three times as long as in Example 1 to set the metering and discharging device on the high discharge side while monitoring the vent portion. The operation continued continuously on the high discharge side, but 10
Since the molten resin was vented up from the vent hole 8 after a lapse of time, it was avoided by adjusting the screw rotation speed. However, the unstretched sheet thereafter was constantly inferior as a product because the polymer discolored to brown constantly flowed out.

[0022]

[Table 1]

[0023]

According to the present invention, in a screw extruder, devolatilization, melting, kneading, mixing and dispersion are carried out in the best condition of the characteristics of the molten resin corresponding to the melting rate from low speed to high speed. It can be pushed out, stable operation can be performed even in a transient state of operation, and stable operation can be performed for a long time. Therefore, by applying the present invention to the production of a film or the like, a film having more excellent physical properties and quality can be obtained in a more stable operating state.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a resin discharge control device for carrying out a method according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Resin supply part 2 Supply device 3 Driving device 4 Weight measuring device 5 Screw 5'Barrel 6 Screw extrusion part 7 Screw driving device 8 Vent hole 9 Connecting pipe 10 Pressure detector 11 Measuring device 12 Measuring discharge part 13 Driving device 14 Rotation speed Detector 15 Screw rotation speed calculator 16 Resin feeder speed calculator 17 Screw extruder controller 18 Resin supply controller

Claims (3)

[Claims] 1. An extruder having a resin supply section, a screw extrusion section, and a metering and discharging section is used to control the screw rotation speed of the screw extruding section based on a signal from the metering and discharging section, and / or a resin. A method for controlling the discharge of resin, characterized in that the supply speed of the supply unit is controlled to measure and discharge the molten resin. 2. A pressure change of the molten resin between the screw extruding part and the metering and discharging part is detected, and the change is time-processed,
The resin discharge control method according to claim 1, wherein the screw rotation speed of the screw extrusion unit is controlled based on the short-term change signal, and / or the supply speed of the resin supply unit is controlled based on the long-term change signal. 3. A method for producing a film, which comprises molding the molten resin discharged by the method according to claim 1 into a film.