JP2000071316A - Automatic starting method for thermoplastic resin extrusion molding machine and production of resin molded product using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automatic starting method for a thermoplastic resin extrusion molding machine with which a start time of extrusion molding is relatively short and loss of raw material is reduced, and a method for producing a molded product using the same. SOLUTION: To start an extrusion molding machine which has been stopped in such as state that a resin remains, at first, an extrusion screw is rotated in the number of rotations lower than that obtaining objective final extrusion quantity and, subsequently a resin of which the quantity is larger than the max. extrusion quantity to be extruded by this number of rotations is intermittently supplied to the extrusion molding machine over several times to be extruded. By this constitution, the resin remaining in the extrusion molding machine is extruded and the next supply time of the resin is operated from real time data of the operation state and/or resin state of the extrusion molding machine to feed back the operation result.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for automatically starting a thermoplastic resin extruder in which resin is stopped in a state where the resin remains, and a method for manufacturing a resin molded article in which extrusion is started by the method.

[0002]

2. Description of the Related Art Thermoplastic resins are melted and extruded by an extruder and formed into various product shapes. The extruder generally comprises an extruder having a built-in extrusion screw and a die attached to the tip of the extruder. Also,
In some cases, a gear pump is provided between the extruder and the mold.

When a thermoplastic resin is extruded using such an extruder, the extruder may be operated for a desired period of time and then stopped for a long time. When the operation is stopped for a long time, the molten resin in the extruder is discharged from the mold as much as possible by the idle operation and stopped. However, the molten resin in the extruder is not completely discharged, and is stopped with the resin remaining.

Conventionally, when starting an extruder stopped in a state where the resin remains as described above, the extruder is heated to a desired molding temperature, and first, the extruder screw is set to a desired final extruding amount. Is rotated at a lower rotation speed than the rotation speed at which is obtained. Then, while checking the current value of the motor of the extruder, the resin pressure at the mold inlet, the resin pressure before and after the gear pump, and the like, use a supply means such as a resin feeder to extrude an amount of the raw material resin corresponding to the above rotation speed. By continuously supplying and extruding the resin, the resin remaining in the extrusion molding machine is discharged,
Thereafter, a method has been proposed in which the number of revolutions of the extrusion screw and the supply amount of the raw material resin are increased in a stepwise manner to obtain a desired final extrusion amount (Japanese Patent Laid-Open No. 10-100235, see the section of the prior art). .

However, in such a conventional method of starting a thermoplastic resin extruder, the resin remaining in the extruder is hardly removed. Therefore, it is necessary to take a relatively long time from starting the supply of the resin to reaching the target final extrusion amount to obtain the first product, that is, the starting time, to remove the residual resin, and considerable raw material loss occurs. . Therefore, as a method for solving the above problem, in order to relatively shorten the start-up time, first, the extrusion screw is rotated at a rotation speed lower than the rotation speed to obtain the desired final throughput, and then extruded at this rotation speed. (Japanese Patent Application Laid-Open No. 4-327923) has been proposed in which a resin larger than the maximum extrusion amount is intermittently supplied to an extruder several times and extruded to discharge the resin remaining in the extruder. ing.

[0006]

However, in such a method of starting a thermoplastic resin extruder, since the supply time when the resin is intermittently supplied several times is uniform, the extrusion time is low. The time required to discharge the residual resin in the molding machine, that is, the start time, largely depends on the state of the molten resin remaining in the extrusion molding machine. Also, if the time during which the resin is fed into the extruder is changed by manual setting in several intermittent feedings to shorten the starting time, the starting time will depend on the skill of the operator who has manually set the feeding time. Dependent. Therefore, if an unskilled operator starts up, the start-up time may be prolonged on the contrary, and the resin pressure in the extruder and around the gear pump abnormally rises due to excessive supply of resin. However, it may cause mechanical trouble.

An object of the present invention is to solve the above-mentioned problems, and to provide a method for automatically starting a thermoplastic resin extruder which has a relatively short start-up time and a small raw material loss at the start of extrusion molding, and to manufacture a resin molded article using the same. The aim is to provide a method.

[0008]

According to the method for automatically starting a thermoplastic resin extruder according to the first aspect of the present invention, when the extruder that has been stopped with the resin remaining is started, first, an extruder screw is first set. The resin is rotated at a rotation speed lower than the rotation speed at which the desired final throughput is obtained, and then the resin extruded at this rotation speed, which is larger than the maximum extrusion volume, is intermittently supplied to the extruder several times to extrude. Thereby, the resin remaining in the extruder is discharged, and the next supply time of the resin is calculated from real-time data of the operating state of the extruder and / or the state of the resin, and the calculation result is fed back. is there.

According to the present invention, the next supply time is calculated from the real-time data of the operating state of the extruder and / or the state of the resin and is fed back by fuzzy inference. That
This is preferable because it is possible to easily design a logic that enables control equivalent to the judgment of a skilled engineer.

The operating state of the extruder and the state of the resin, which are monitored in real time, include the number of rotations of the extrusion screw of the extruder and the current value of the motor, the number of rotations of the gear pump and the current value of the motor, the resin feeder. And the current value of the motor, the outlet of the extruder, the outlet of the gear pump, the resin pressure and the resin temperature at the inlet of the mold.

According to a third aspect of the present invention, there is provided a method for producing a resin molded article, wherein extrusion molding is started by the automatic starting method of the thermoplastic resin extruder according to the first or second aspect.

(Function) In the method for automatically starting a thermoplastic resin extruder according to the first aspect of the present invention, when starting the extruder that has been stopped with the resin remaining, first, the extruder screw is moved to the desired final position. The extruder is rotated at a lower rotational speed than the rotational speed at which the extruded amount is obtained, and then the resin extruded at this rotational speed, which is larger than the maximum extruded amount, is intermittently supplied to the extruder several times and extruded. Because of the resin supplied intermittently, strong residual pressure is applied to the resin remaining in the extruder, and this pressure causes the hard-to-remove resin adhering to the inner wall of the extruder to flow well and quickly Get out.

[0013] Further, since there is a time during which the resin is not supplied due to the intermittent supply of the resin, the resin pressure in the extruder is alleviated, thereby preventing damage to each device. In particular, when the resin is intermittently supplied to the extruder so that the time during which the resin is not supplied is longer than the time during which the resin is supplied, when the resin does not easily flow due to insufficient heating of the residual resin, Damage to each device is reliably prevented.

Further, the resin remaining in the extruder is discharged, and the next supply time of the resin is calculated from real-time data of the operating state of the extruder and / or the state of the resin, and the calculation result is fed back. Therefore, the time required to discharge the residual resin in the extruder, that is, the starting time is relatively shorter than when the supply time of the resin is uniform or when changed by manual setting by an operator. Can be shorter. Also,
Since the above-mentioned intermittent supply is performed automatically, the start time does not depend on the skill of the operator, and it is possible to reliably prevent the abnormal increase of the resin pressure due to the excessive supply of the resin and the damage of each device due to it.

According to a second aspect of the present invention, there is provided a method for automatically starting a thermoplastic resin extruder, wherein the next supply time is calculated and fed back from real-time data of the operating state of the extruder and / or the state of the resin. Since the control is performed by fuzzy inference, it is possible to easily design a logic capable of performing control equivalent to the judgment of a skilled engineer.

According to a third aspect of the present invention, there is provided a method for producing a resin molded article, wherein the extrusion molding is started by the automatic starting method of the thermoplastic resin extruder according to the first or second aspect. At the time of starting, the starting time is relatively short, and material loss is small.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The inventions according to the first to third aspects will be specifically described below with reference to the drawings. FIG. 1 is an explanatory view showing an example of an extruder used in the inventions according to the first to third aspects. In FIG. 1, 10 is an extruder incorporating an extrusion screw, 20 is a gear pump, 30 is a screen changer, 40 is a mold, 50 is a resin feeder, 60 is a plasticizer pump, and 70 is a computer. Extruder 10, gear pump 20, resin feeder 5
0. Each of the plasticizer pumps 60 is operated according to an instruction from the computer 70.

The rotation speed of the extrusion screw of the extruder 10 and the current value of the motor 11 thereof, the rotation speed of the gear pump 20 and the current value of the motor 21, the rotation speed of the resin feeder 50 and the current value of the motor 51, the plasticizer pump 6
The rotation speed of 0 and the current value of the motor 61 are all input to the computer 70. The resin pressure at the outlet of the extruder 10, the outlet of the gear pump 20, and the resin pressure at the inlet of the mold 40 are also input to the computer 70 by the respective pressure gauges 22, 31, 41.

Furthermore, the current value of the motor 11 of the extruder 10, the current value of the motor 21 of the gear pump 20, the outlet of the extruder 10, the resin pressure at the outlet of the gear pump 20 and the resin pressure at the inlet of the mold 40 each have a warning level. Is set.
When the alert level is exceeded, all the devices are stopped.

A case where a plasticized polyvinyl butyral sheet is extruded using such an extruder will be described. The extruder has been operated for a desired period and then stopped with the resin remaining.

First, the extruder is heated to a desired molding temperature, for example, 180 ° C. Then, the gear pump 20 and the screw of the extruder 10 are operated in this order. In this case, the gear pump 20 and the screw of the extruder 10 are rotated at a rotation speed lower than the rotation speed at which the desired final extrusion amount is obtained, for example, at a rotation speed of about 30 to 50%.

Next, the resin feeder 50 and the plasticizer pump 60 are operated and adjusted to adjust the resin feeder 50 and the plasticizer pump 60 so that the resin extruded at the above-mentioned rotation speed exceeds the maximum extruded amount, for example, 1.2 wt.
〜1.5 times the resin is intermittently fed to the extruder.

When intermittent supply is performed several times, it is preferable to use fuzzy inference control as a method of calculating the time during which the next resin supply is performed. The operating state of the extruder, the state of the resin, the rotation speed of the extrusion screw of the extruder and the current value of its motor, the rotation speed of the gear pump and the current value of the motor, the rotation speed of the resin feeder and the current value of the motor, The resin pressure and resin temperature at the outlet of the extruder, the outlet of the gear pump, and the inlet of the mold are input to the computer 70 as real-time data. The computer 70 calculates the time to supply the next resin based on the real-time data.

As a method of calculating the time to supply the next resin by fuzzy inference, for example, the maximum value of the resin pressure at the outlet of the gear pump 20 in the last intermittent supply and the last resin Then, the time when the next resin supply is to be performed is calculated based on the supply time. In the control unit 72 of the computer,
In response to the value calculated by the fuzzy calculation unit 71, a time to supply the next resin to the resin feeder 50 is output.

FIG. 2 is an explanatory diagram showing an example of a fuzzy rule in the fuzzy operation section 71 described above.
FIG. 4 is an explanatory diagram showing an example of the membership function of the fuzzy rule.

The fuzzy operation unit 71 executes fuzzy inference based on fuzzy rules describing the operator's empirical rules shown in FIG. 2 and membership functions shown in FIG. In the example of the fuzzy rule shown in FIG. 2, the maximum value of the resin pressure at the outlet of the gear pump 20 in the previous resin supply and the previous resin supply time are input, and the next resin supply time is output.

A part of the fuzzy rule will be specifically described with reference to FIG. Rule 1: If the previous resin supply time is A (0 to 5 s), the next resin supply time is B (0 to 10 s). Rule 2: The last resin supply time is B (0 to 10 s), and the gear pump outlet resin pressure is a (0 to 100 kgf / cm).
^{If 2} ), the next resin supply time is set to E (15 to 25 s). Rule 3: The previous resin supply time is B (0 to 10 s), and the gear pump outlet resin pressure maximum value is b (0 to 200 kgf / c)
m ² ), the next resin supply time is D (10 to 20 s)
And Rule 4: Last resin supply time B (0 to 10 s), gear pump outlet resin pressure maximum value c (100 to 300 kgf)
/ Cm ² ), the next resin supply time is D (10 to 20).
s). Rule 5: The previous resin supply time is B (0 to 10 s), and the gear pump outlet resin pressure maximum value is d (200 to 400 kgf).
/ Cm ² ), the next resin supply time is C (5 to 15).
s). Rule 6: The previous resin supply time is B (0 to 10 s), and the gear pump outlet resin pressure maximum value is e (300 to 500 kgf).
/ Cm ² ), the next resin supply time is B (0 to 10
s). Rule 6: The previous resin supply time is B (0 to 10 s), and the gear pump outlet resin pressure maximum value is f (400 kgf / cm ²
), The next resin supply time is set to A (0 to 5 s).

That is, according to this rule, the resin supply is performed for a predetermined time at the time of starting, and then, when the maximum value of the resin pressure at the outlet of the gear pump 20 is small, the next resin supply time is extended, and the resin supply at the outlet of the gear pump 20 is performed. When the maximum value of the resin pressure is large, the next resin supply time is equal to or shorter than the previous resin supply time. FIG. 3 shows the membership function of the time during which the resin is supplied. In this example, the membership function is a triangle, but it may be a bell-shaped or trapezoidal function. The label of the time during which the resin is being supplied is divided into seven as shown in FIG. 3, for example. A = 0-5s B = 0-10s C = 5-15s D = 10-20s E = 15-25s F = 20-30s G = 25-30s

FIG. 4 shows the membership function of the maximum value of the resin pressure at the outlet of the gear pump in the previous intermittent supply, and its label is divided into, for example, six as shown in FIG. a = 0 to 100 kgf / cm ² b = 0 to 200 kgf / cm ² c = 100 to 300 kgf / cm ² d = 200 to 400 kgf / cm ² e = 300 to 500 kgf / cm ² f = 400 kgf / cm ² or more

Next, a method of intermittently supplying the resin to the extruder several times using fuzzy inference will be described. The fuzzy inference can be performed in the same manner as a normal fuzzy control method according to the fuzzy rules shown in FIG. 2 and the membership functions shown in FIGS.

As a condition for starting, the time during which the first intermittent supply of the resin is supplied irrespective of the resin pressure at the outlet of the gear pump is set to, for example, 0 to 10 s. At that time, the maximum value of the resin pressure at the gear pump outlet is detected, and is input to the fuzzy calculation unit as a feedback signal together with the time during which the resin is supplied this time. The fuzzy calculation unit selects all the fuzzy rules having the antecedent part corresponding to the input operating condition, and obtains the degree of conformity to the entire antecedent part with each rule. Next, based on the degree of adaptation, the membership functions for the time of supplying the next resin, which is the operation amount of the consequent part, are respectively corrected. Next, the amount of operation is determined from the membership function of the amount of operation obtained by each rule, generally using a method of taking the center of gravity. This operation amount is output to the resin feeder through the fuzzy control unit as the time for supplying the next resin.

When the resin is intermittently supplied, it is preferable that the time during which the resin is not supplied is set to be longer than the time during which the resin is supplied. In this case, the time is preferably longer than the time required for the resin to pass from the resin supply port of the extruder 10 to the outlet of the gear pump 20.
It is set to about 0 to 60 seconds.

This intermittent supply is repeated when the resin is supplied for a predetermined time (for example, 20 seconds) or more.
And the resin pressure at the outlet of the gear pump 20 and the resin pressure at the inlet of the mold 40 are respectively reduced to or below predetermined values. The number of repetitions is generally about 3 to 5 times. Thus, the resin remaining in the extruder is discharged.

Thereafter, while checking the current value of the motor of the extruder, the resin pressure at the mold inlet, the resin pressure before and after the gear pump, and the like, the rotation speed of the extrusion screw and the supply amounts of the resin and the plasticizer are gradually increased. To obtain the desired final throughput. Thus, a desired product is manufactured. The operation of increasing the number of revolutions of the extrusion screw and the supply of the resin and the plasticizer stepwise is performed in the same manner as in the related art, for example, as described in JP-A-10-52854. If so, it is even better that the starting time can be made relatively short.

As in the present invention, first, the extruder screw is rotated at a lower rotational speed than the rotational speed at which the desired final extruded amount is obtained, and then the resin extruded at this rotational speed is intermittently extruded at a higher rotational speed than the maximum extruded amount. When the resin is supplied to the extruder and extruded, the resin that is intermittently supplied causes a strong impact pressure on the resin remaining in the extruder, and this pressure causes the resin to adhere to the inner wall of the extruder. The hard-to-remove resin flows well and escapes quickly.

Also, due to the intermittent supply of the resin, there is a time period during which the resin is not supplied, so that the resin pressure in the extruder is reduced and damage to each device is prevented. In particular, when the resin is intermittently supplied to the extruder so that the time during which the resin is not supplied is longer than the time during which the resin is supplied, when the resin does not easily flow due to insufficient heating of the residual resin, Damage to each device is reliably prevented.

Further, when the resin is intermittently supplied several times as described above, the time to supply the next resin is calculated from the operating state of the extruder and / or real-time data of the resin state. Since the calculation result is fed back, the time required to discharge the residual resin in the extruder is smaller than when the supply time of the resin is uniform or changed by manual setting by the operator. That is, the starting time can be relatively shortened. Also, the above-mentioned intermittent supply is performed automatically, so the start time does not depend on the skill of the operator,
It is possible to reliably prevent an abnormal increase in resin pressure due to an excessive amount of resin supply and damage to each device due to the abnormal increase in resin pressure.

[0038]

EXAMPLES Examples and comparative examples of the present invention will be described below. (Example) First, the extruder, which was stopped with the plasticized polyvinyl butyral resin colored in blue remaining, was heated to 180 ° C. Then, the gear pump 20 and the extrusion screw of the extruder 10 were rotated at 40 rpm.
The number of revolutions is set at the desired final extrusion rate (1000 kg / h).
r) was 40% of the number of revolutions (100 rpm) to obtain.

Next, the resin feeder 50 and the plasticizer pump 60 are operated and adjusted, and the resin (480 kg / hr) which is 1.2 times larger than the maximum extruded amount (400 kg / hr) extruded at the above-mentioned rotation speed. ) Was fed to the extruder for 5 seconds. After the resin supply for 5 seconds, the resin supply was stopped for 30 seconds. Then, after the resin is supplied to the extruder, the outlet of the extruder 10, the outlet of the gear pump 20 and the mold 4
The resin pressure was measured at the entrance of 0 and input to the computer 70. Fuzzy operation unit 71 of computer 70
Then, when the next resin supply time was calculated from the input maximum value of the resin pressure at the gear pump outlet and the resin supply time, the result was 20 seconds, and the result was output to the resin feeder through the fuzzy control unit. Therefore, the above 3
After the stop for 0 seconds, the second resin supply was performed for 20 seconds, and then the supply was stopped again for 30 seconds.

During the second intermittent supply, the resin pressure was measured in the same manner as above, and the next (third) resin supply time was calculated to be 20 seconds. Based on the result, the third resin supply was performed. Performed for 20 seconds. Subsequently, the supply was stopped again for 30 seconds. When the resin pressure was measured in the same manner as above during the third intermittent supply, the maximum resin pressure was 120, 220, and 180 kg at the outlet of the extruder 10, the outlet of the gear pump 20, and the inlet of the mold 40, respectively.
f / cm ² . Therefore, when the resin is supplied for a predetermined time (20 seconds) or more, the resin pressures at the outlet of the extruder 10, the outlet of the gear pump 20, and the inlet of the mold 40 become lower than predetermined values, respectively. The supply was completed in the above three times. The elapsed time during this time is 2.3
The loss of the raw material resin was 6.0 kg.

Thereafter, while checking the current value of the motor of the extruder, the resin pressure at the entrance of the mold, the resin pressure before and after the gear pump, etc., the extruding screw is set at 40 rpm and the resin supply amount is set at 300 kg.
/ Hr for 2 minutes, followed by an extrusion screw of 60 rpm, a resin feed rate of 500 kg / hr for 1.5 minutes, followed by an extrusion screw of 80 rpm
m, extruding the resin at a resin supply rate of 700 kg / hr for 1.5 minutes, subsequently extruding the resin at an extrusion screw of 100 rpm at a resin supply rate of 900 kg / hr for 1.5 minutes, and finally adjusting the resin supply rate to the desired final extrusion rate ( 1000kg / h
r). The elapsed time during this period was 6.5 minutes, and the loss of the raw material resin was about 62.5 kg. Thus, the thickness is 0.
A plasticized polyvinyl butyral sheet without coloration at 76 mm was produced. In this case, the time from the start of the supply of the resin to the setting of the target final extrusion amount until the first product is obtained, that is, the starting time is 8.8 minutes (2.3 minutes + 6.5 minutes), and the loss of the raw material resin is 68.5kg (6.0kg + 62.5k
g).

FIG. 5A shows the relationship among the number of rotations of the extrusion screw, the resin supply amount (extrusion amount), and the elapsed time of extrusion in the above embodiment. In FIG. 5A, the rotation speed of the extrusion screw is represented by a dotted line, and the resin supply amount (extrusion amount) is represented by a solid line. (Comparative Example 1) First, the extruder, which was stopped with the plasticized polyvinyl butyral resin colored in blue remaining, was heated to 180 ° C. Then, the gear pump 20 and the extrusion screw of the extruder 10 were rotated at 40 rpm. The number of revolutions is set at the target final extrusion rate (1000 kg /
hr) was 40% of the number of revolutions (100 rpm) at which to obtain the same.

Next, the resin feeder 50 and the plasticizer pump 60 are operated and adjusted, and the resin (480 kg / hr) which is 1.2 times larger than the maximum extruded amount (400 kg / hr) extruded at the above-mentioned rotation speed. ) Was fed to the extruder for 15 seconds. After the resin supply for 15 seconds, the resin supply is stopped for 3 seconds.
Stopped for 0 seconds. This was repeated six times to terminate the intermittent supply. The elapsed time during this period was 4.5 minutes, and the loss of the raw material resin was 12.0 kg.

Thereafter, while checking the current value of the motor of the extruder, the resin pressure at the mold inlet, the resin pressure before and after the gear pump, and the like, the rotation speed of the extrusion screw is 40 rpm, and the resin supply amount is 3.
The resin is extruded at 00 kg / hr for 2 minutes, and subsequently, the number of rotations of the extrusion screw is 60 rpm, and the resin supply amount is 500 k.
The resin was extruded at 1.5 g / hr for 1.5 minutes, followed by an extruder screw rotation speed of 80 rpm and a resin supply of 700 kg / hr.
The resin was extruded at 1.5 hours for 1 hour, and the rotation speed of the extrusion screw was 100 rpm, and the resin supply amount was 900 kg / h.
The resin was extruded at 1.5 r for 1.5 minutes, and finally the resin supply was set at the target final extrusion rate (1000 kg / hr). The elapsed time during this period was 6.5 minutes, and the loss of the raw material resin was 62.5 kg.

Thus, a non-colored plasticized polyvinyl butyral sheet having a thickness of 0.76 mm was produced. In this case, the time from the start of the supply of the resin to the setting of the target final extrusion amount until the first product is obtained, that is, the starting time is 1 hour.
1.0 minutes (4.5 minutes + 6.5 minutes), loss of raw resin is 7
The weight was 4.5 kg (12.0 kg + 62.5 kg).

FIG. 5B shows the relationship among the number of rotations of the extrusion screw, the amount of resin supplied (the amount of extrusion) and the elapsed time of extrusion in the above embodiment. In FIG. 5B, the rotation speed of the extrusion screw is represented by a dotted line, and the resin supply amount (extrusion amount) is represented by a solid line.

(Comparative Example 2) First, the extruder, which was stopped while the plasticized polyvinyl butyral resin colored in blue remained, was heated to 180 ° C. Then, the gear pump 20 and the extrusion screw of the extruder 10 are set at 25 rpm.
And rotated. This number of revolutions is determined by the desired final extrusion rate (10
00 kg / hr) of 25 (100 rpm)
%Met.

Next, the resin feeder 50 and the plasticizer pump 60 are operated and adjusted, and the resin (200 kg / hr) which is 20% smaller than the maximum extrusion amount (250 kg / hr) extruded at the above rotation speed. Was continuously fed to the extruder for 8.5 minutes. The loss of raw resin during this time is 2
It was 8.3 kg.

Thereafter, while checking the current value of the motor of the extruder, the resin pressure at the mold entrance, and the resin pressure before and after the gear pump, the rotation speed of the extrusion screw is 35 rpm, and the resin supply amount is 3
The resin was extruded at 00 kg / hr for 1.5 minutes, and subsequently, the number of rotations of the extrusion screw was 45 rpm, and the resin supply amount was 400.
The resin was extruded at 1.5 kg / hr for 1.5 minutes, followed by a rotation speed of an extrusion screw of 55 rpm and a resin supply amount of 500 kg.
/ Hr for 1.5 minutes, followed by an extrusion screw rotation speed of 65 rpm and a resin supply of 600 kg / h.
The resin was extruded at 1.5 rpm for 1.5 minutes, followed by extruding the resin for 1.5 minutes at a rotation speed of the extrusion screw of 75 rpm and a resin supply amount of 700 kg / hr, and subsequently at a rotation speed of the extrusion screw of 85 rpm and a resin supply amount of 800 kg / hr. 1.
The resin is extruded for 5 minutes, and subsequently, the resin is extruded for 1.5 minutes at a rotation speed of the extrusion screw of 95 rpm and a resin supply amount of 900 kg / hr.
rpm, the resin feed rate to the desired final extrusion rate (1000 kg
/ Hr). The elapsed time during this period was 10.5 minutes, and the loss of the raw material resin was 105.0 kg.

Thus, a plasticized polyvinyl butyral sheet having a thickness of 0.76 mm and no coloring was produced. In this case, the time from starting the supply of the resin to obtaining the first product by setting the target final extrusion amount, that is, the starting time is about 1 hour.
9.0 minutes (8.5 minutes + 10.5 minutes), the loss of the raw material resin was about 133.3 kg (28.3 kg + 105.0 kg).

FIG. 5C shows the relationship between the rotation speed of the extrusion screw, the resin supply amount (extrusion amount), and the elapsed time of extrusion in the above embodiment. In FIG. 5C, the rotation speed of the extrusion screw is represented by a dotted line, and the resin supply amount (extrusion amount) is represented by a solid line.

According to the first aspect of the present invention, the starting time of the extrusion molding is relatively short, and the starting time is relatively short.
Less material loss. Since the invention according to claim 2 is as described above, it is possible to easily design a logic capable of performing control equivalent to the judgment of a skilled technician at the time of starting the extrusion, and the starting time is relatively short. In addition, less material loss is required. Since the invention described in claim 3 is as described above, the starting time at the start of the extrusion molding is relatively short, and the raw material loss can be reduced.

[Brief description of the drawings]

FIG. 1 is an explanatory view of an extruder used in the present invention.

FIG. 2 is an explanatory diagram showing a fuzzy rule when control by fuzzy inference is performed as an example of the present invention.

FIG. 3 is an explanatory diagram showing a membership function of a time during which a resin is supplied when control is performed by fuzzy inference as an example of the present invention.

FIG. 4 is an explanatory diagram showing a membership function of the maximum value of the resin pressure at the outlet of the gear pump in the previous intermittent supply when control based on fuzzy inference is performed as an example of the present invention.

FIG. 5A is a graph showing the relationship between the number of rotations of an extrusion screw, a resin supply amount (extrusion amount) and an elapsed time of extrusion in an example of the present invention, and FIGS. 5B and 5C are comparative examples, respectively. It is a graph which shows the rotation speed of the extrusion screw in 1 and 2, the resin supply amount (extrusion amount), and the extrusion elapsed time.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Extruder 20 Gear pump 30 Screen changer 40 Die 50 Resin feeder 60 Plasticizer pump 70 Computer 71 Fuzzy operation part

Claims (3)

[Claims] When starting an extruder which has been stopped in a state where the resin remains, first, an extruder screw is rotated at a lower rotational speed than a rotational speed at which a desired final throughput is obtained. The resin that is larger than the maximum extruded amount extruded is intermittently supplied to the extruder several times and extruded, thereby discharging the resin remaining in the extruder, operating the extruder and / or Alternatively, a method for automatically starting a thermoplastic resin extruder, comprising calculating the next supply time of the resin from real-time data of the state of the resin and feeding back the calculation result. 2. The extrusion method according to claim 1, wherein the next supply time is calculated from real-time data of the operating state of the extruder and / or the state of the resin, and is controlled by fuzzy inference when feeding back the time. Automatic starting method of thermoplastic resin for molding machine. 3. A method for producing a resin molded product, wherein extrusion molding is started by the automatic starting method of the thermoplastic resin extruder according to claim 1 or 2.