JPH087131B2 - Automatic test method and device for capillary type flow characteristic test device - Google Patents

Description

Description: TECHNICAL FIELD The present invention mainly relates to an automatic test method and an apparatus for a capillary type flow characteristic test device for performing a capillary type flow characteristic test of a molten polymer such as a synthetic resin. is there.

(Prior Art) Conventionally, as shown in FIG. 6, a heated furnace body 1
The moving speed of the piston 2 to be pushed into the inside is commanded 3 by the operation of selecting the operation button, and the displacement of the lead screw 7 is detected through the computer 4, the pushing motor 5, the pushing mechanism 6, the lead screw 7, etc. 'On the other hand, the load cell 8 in the crosshead 7A detects the pushing load 9 and inputs it to the computer 4 to display various data.
39 or plotter 40.

(Problems to be Solved by the Invention) Conventionally, a capillary flow characteristic of a molten polymer is measured while temporarily changing the flow rate of a sample by setting a computer program, and a relaxation time when changing the flow rate. It was known to provide. It has also been known to perform degassing in the barrel. Further, it is also known that the measurement signal data detected by this measurement is processed by a computer and output to a display unit.

However, in the above-mentioned publicly known examples, flow control by a program set in a computer, degassing in the barrel, computer processing of the measurement result and display, etc. are individually proposed.

On the other hand, in the present invention, in order to measure the flow characteristics of a wide variety of plastic materials having a wide range of viscoelastic characteristics with reproducibility and reliability by means of a capillary flow characteristic test, it is necessary to use a molten polymer during the test. It is based on the inventor's finding that it is essential to strictly control the action of, and in order to realize this finding, a computer and a computer for improving measurement accuracy and safety and labor saving are provided. An object of the present invention is to provide an automatic test method and its apparatus in a capillary type flow characteristic test apparatus by purposely configuring the whole including the apparatus and the test method using the setting program.

(Means for Solving the Problems) In order to solve the above problems, in the present invention, a modifiable computer programming software system is appropriately improved, and a piston position detector of a pushing mechanism, a load cell, an extrusion motor, By connecting various control units to the computer mechanism, the program setting of the test operation or the method of capturing the measurement data was improved, and the moving speed and moving distance of the crosshead at the time of pre-extrusion after sample loading were clarified. By determining the crosshead movement distance at the extrusion speed and inputting a stable measurement value of the load value, the measurement data can be automatically fetched.

In the first process of degassing the barrel, safety measures are taken to stop the operation when the load exceeds the set value, and in the second process of pre-extrusion, the sample flow is stabilized and the subsequent main measurement is performed. It has a preliminary action to enhance the reproducibility of the measurement in the third process, and in the third process, the end of the main measurement is determined by the movement position of the crosshead, so that a wide variety of samples with a wide range of viscoelastic properties can be safely used. And it is possible to measure with high accuracy.

Also, the plotting of various data was carried out by a quadratic approximation curve using the least squares method, and both stress and viscosity were plotted on the graph as plotter output.

That is, the data processing confirms the recorder value after the measurement, and if it is judged that correction is necessary due to melt fracture etc., input it from the computer keyboard so that the data can be corrected, and the quadratic formula obtained by calculation is used. The constants are also listed under the printer data.

(Operation) According to the automatic program setting method configured as described above, (1) the moving speed of the piston for sample extrusion can be changed.

(2) The moving distance of the crosshead can be detected.

(3) It is possible to start, pause, restart, stop, end, etc. the measurement by detecting the time and detecting the crosshead position.

(4) It is possible to change the moving direction of the crosshead.

(5) By setting the measurement speed, it is possible to change the moving speed of the crosshead during the measurement.

(6) It is possible to recognize that the load value is stable by detecting the load and input it as the measured value.

(7) It is possible to input the measurement value by detecting the moving distance of the crosshead. Further, the detection distance can be set and changed depending on the moving speed of the crosshead.

(8) All the above items can be done automatically.

(Example) An example will be described with reference to the drawings (FIGS. 1 to 5). FIG. 1 is a schematic diagram of the principle of the present invention. According to this figure, first, a capillary type flow characteristic test device,
The automatic test equipment will be described.

An extrusion motor 23 and a reduction gear system 22A directly connected to the extrusion motor 23 are fixedly provided at the upper position of the capillary type flow characteristic test device. A parent screw rod 22 is screwed into the reduction gear system 22A, and the parent screw rod 22 is moved in the vertical vertical direction by the rotation of the pushing motor 23. The lower end of the parent rod 22 pivotally supports the crosshead 21 at the center of its upper surface, and the loadcell 18 as a load detector is provided at the center of the crosshead 21.
Is installed internally. Further, the crosshead 21 has the piston 13 facing downward at the center of its lower surface, and its base end is stably supported and connected. Further, the base end surface of the piston 13 is in contact with the detection end protruding below the load cell 18. The crosshead 21 includes a molten polymer 12A, which is a material to be tested, and a lead screw rod 22 which acts on the material to be tested.
It is a component that passes through and, and is vertically guided by a pair of columns of a gate-shaped frame provided upright in the capillary type flow characteristic testing device.

The piston 13 is inserted into the center hole of a bottomed, elongated cylindrical barrel 10 having a bottom. This barrel 10 is a furnace body 11
The barrel 10 is surrounded by a temperature of 60
The accuracy is maintained within ± 0.5% of the set temperature in the temperature range of ℃ to 500 ℃. The molten polymer 12A, which is the sample 12, is received in the center hole.

In the figure, reference numeral 12B is a molten polymer filament formed by the molten polymer 12A extruded from the bottom of the barrel 10 by the tip of the piston 13 through a capillary 14 penetrating the bottom of the barrel 10. The molten polymer filament 12B which is slightly swollen and protrudes downward is surrounded by a heat retaining chamber 15, and a ring-shaped die swell measuring machine 16 using a laser beam is provided around the heat retaining chamber 15.
Is provided. The die swell measuring machine 16 detects the state of the molten polymer filament 12B, and the detection signal is transmitted to the computer 20 via the amplifier 17.

A speed control unit 24 is arranged between the extrusion motor 23 and the computer 20, and the extrusion motor 23 is
Since it is controlled by a program preset in the computer 20, a master screw rod 22 screwed with the reduction gear system 22A,
The crosshead 21 pivotally supported by the parent screw rod 22 is moved vertically downward by the operation of the pushing motor 23 as shown by an arrow line A in the drawing. It should be noted that it can also move upward as indicated by the arrow B.

The position of the crosshead 21 is detected by a linear sensor type position detector 26 provided in parallel with the parent rod 22, and the position detection signal I is transmitted to the computer 20 as shown.

The crosshead 21 descends, and in the barrel 10, the piston
When the tip of 13 extrudes the molten polymer 12A, the load cell 18 detects the extruding load with an accuracy within an error of ± 1%. This load detection signal K is transmitted to the computer 20 via the amplifier 19 as shown. In the figure, reference numeral 25 is a pressure detector provided in place of the load cell 18, and the pressure detector 25 is provided on the inner bottom side surface of the barrel 10 and is made of molten polymer.
The pressure applied to 12A is directly detected, and the load detection signal K is transmitted to the computer 20 via the amplifier 19.

The reduction gear system 22A will be described below with reference to FIG. The small gear 28 is attached to the rotary shaft of the extrusion motor 23, and the worm 31 is attached to the rotary shaft 30 of the large gear 29 meshed with the small gear 28.
I am attached. On the other hand, the main wheel 22 has a worm wheel
The spiral formed on the inner peripheral surface of 32 is screwed, and the worm 31 is meshed with the gear on the outer peripheral surface of the worm wheel 32. As a result, the rotation of the extrusion motor 23 is controlled by the parent screw.
Converted to vertical movement of 22 and crosshead 21.

In addition, the gear 33 attached to the tip of the rotary shaft 30 and this gear
An encoder-type position detector 27 is directly connected to a gear 34 meshed with 33. This encoder type position detector 27
The position of the main screw rod 22 is detected from the number of rotations,
The position detection signal is transmitted to the computer 20. A plotter 38 is connected to the computer 20.

The capillary type flow characteristic testing device is equipped with either the encoder type position detector 27 or the linear sensor type position detector 26.

Hereinafter, a capillary type flow characteristic testing device equipped with this linear sensor type position detector 26 will be described with reference to FIG.

An elongated pipe-shaped linear sensor parallel to the main rod 22
35 is set upright, and a thin and slightly elongated cylindrical position detector 26 is inserted into this linear sensor 35.
Since the upper end of the position detector 26 and the upper end of the parent screw rod 22 are connected by a short beam member, the position of the position detector 26 always coincides with the position of the parent screw rod 22.

With the above configuration, the vertical movement of the parent screw rod 22, that is, the vertical movement of the crosshead 21 and the piston 13 is performed by the computer.
Controlled by 20. Further, since the position detection signal I of the crosshead 21 is transmitted to the computer 20, the position of the crosshead 21 is always detected during the measurement. further,
Since the load applied to the molten polymer 12A is transmitted to the computer 20, the load applied to the molten polymer 12A, which changes with the vertical movement of the crosshead 21, is always detected.

The plotter 38 processes the data in a known plotter format, and when it judges that it is a melt fracture (the die swell measuring machine 16 melts the filament 12
When B division is detected), the color is changed and plotted, so that it is not included in the least squares processing of the data.

In addition, the X-axis and Y of the above plotter format
The scale of the axis can be freely changed, and the logarithm is used.

The data can be plotted at multiple points at the same time and are distinguished by different marks.

The program setting in the computer 20 will be described below.

That is, the programs are set in the computer 20 in the following order.

(1) About degassing Automatic measurement starts when the start switch (not shown) is pressed, and at the same time as this start, the crosshead position detection signal, the load detection signal and temperature of the molten polymer in the barrel, and the elapsed time The computer starts reading as measurement data. Crosshead 21 speed 200mm / min
Then, the crosshead 21 is stopped when a load of about 10 kg is detected. However, if this load is not detected within 110 mm from the start position, an alarm sounds and automatic measurement is stopped. Three minutes after turning on the start switch, the first process of lowering the crosshead 21 at a speed of 20 mm / min to degas the barrel 10 begins. However, the load is 500 kg
If the value exceeds the limit, the descent of the crosshead 21 is stopped and an alarm sounds and automatic measurement is stopped. Degassing
It ends when the crosshead 21 moves down 110 mm from the automatic measurement start position.

(2) Measurement 6 minutes after turning on the start switch, lower the crosshead 21 at a speed of 500 mm / min and start measurement. Cross head 2
In No. 1, the second step pre-extrusion is performed from the 110 mm position to the 120 mm position for the first time. In the second step, the flow stabilization of the molten polymer is performed. The main measurement of the third process is
It starts when the crosshead is 120 mm lower than the automatic measurement start position, that is, when the stroke of the crosshead reaches 120 mm.

Also, a relaxation time of 3 to 5 seconds is set for each speed. As the measurement points, the values of the three points before the measurement are taken and the average value is used. When the main measurement of the third process is started at a high extrusion speed of 500 mm / min due to the descent of the crosshead, the stroke of the crosshead at this speed is specified to be 40 mm as shown in the table below. That is, when the crosshead further descends 40 mm from the position (120 mm) at which the third process starts to reach the position of 160 mm, the measuring step at the extrusion speed of 500 mm / min ends. At that time, the computer reads the position detection signal, the elapsed time, and the load detection signal when the crosshead stroke reaches 39.9 mm as the measurement data. Then, after a relaxation time of 3 to 5 seconds, the extrusion speed by the crosshead is set to 200 mm / min,
The next measurement phase with a crosshead stroke of 30 mm is resumed. This third process ends when the crosshead reaches a position 290 mm lower than the automatic measurement start position.

After the measurement is completed or when an error occurs, an alarm sounds and it can be canceled with the reset switch.

The maximum load can be set arbitrarily, and it will stop when the set load is exceeded. The maximum load is set below the detection limit of the load cell. The measurement can be switched from automatic to manual at any time. The measured data can be saved on a data disk and recalled as appropriate for modification. It is also a program that can erase the measurement data in the disc.

The following table gives an example of the relationship between the extrusion speed by the crosshead (also referred to as the measurement speed or the measurement setting speed), the stroke of the crosshead specified at each extrusion speed (also referred to as the specified stroke), and the crosshead position. .

(3) Data processing Measured data is processed by the computer 20. After the measurement, the recorder value is checked, and if correction is necessary due to melt fracture, etc., it can be input from the computer keyboard and corrected.

For plotter output, both stress and viscosity can be plotted using the least squares method.

M, which is an index of the molecular weight distribution, is defined by the shear rate ratio D ₂ / D ₁ . This index M generally correlates with the molecular weight distribution by GPC (gel permeation chromatography) method.

Here, the shear rate D ₂ is the maximum value at the shear stress level allowed when measuring M, which is an index of the molecular weight distribution, and when the shear stress level exceeds this maximum value, the above-mentioned melt fracture occurs. It may occur. On the other hand, the shear rate D ₁ is the minimum value at the allowable shear stress level, and setting a shear stress level below this minimum value requires measurement at an extremely low shear rate, which is not suitable for practical use. . These D ₂ and D ₁ can be obtained from the calculation of quadratic approximation from the data values of each shear rate and shear stress.

The flow chart of the above program is as follows. Since the crosshead 21 and the piston 13 are connected to each other, the same operation is performed.

FIG. 2 (a) is an example of measurement from high speed to low speed and shows the set program in a graphic form. As shown in this figure, the molten polymer 12A is tested according to the program. In FIG. 2 (a), the position of the crosshead descending movement distance 290 mm corresponds to the end of the main measurement (third step) described in the flowchart showing the above measurement sequence.

Further, FIG. 2 (b) shows an example of measurement from low speed to high speed, which is a graphic representation of another set program. The difference between the program settings of FIG. 2 (a) and FIG. 2 (b) is as follows.

That is, in the program setting of FIG. 2 (a), the descending movement distance of the piston 13 is set to gradually decrease with the passage of time.

On the other hand, in the program setting of FIG. 2 (b), the descending movement distance of the piston 13 is set to gradually increase with the passage of time.

In any case, various types of program settings can be made in the computer 20, and the examples shown here are only examples.

(Effects of the Invention) Since the present invention has the above-described configuration, it has the following unique effects.

Tests can be performed according to an automatically set program without the need for troublesome work compared to conventional techniques, the measurement efficiency is further improved, and the viscoelasticity of various plastic materials with a wide range of viscoelastic properties can be measured with high accuracy. You can In addition, the measurement time can be further shortened, and just by pressing the fully automatic start switch button, any person can easily operate it, and measurement can be performed without waste and time.

In the first process, safety measures are taken to stop the operation where the load exceeds the set value, so the measurement is stopped when the load exceeds the set pressure.

In the second step, the flow of the sample is stabilized and a preliminary action is performed to increase the reproducibility of the measurement in the subsequent third step of the main measurement.In the third step, the end of the main measurement is determined by the crosshead movement position. Since it has been decided, various types of samples can be measured safely and with high reproducibility and accuracy.

[Brief description of drawings]

FIGS. 1 to 5 show the present invention. FIG. 1 is a schematic view of the principle of the present invention, and FIGS. 2 (a) and 2 (b) are graphic representations of computer program settings. The horizontal axis represents time, and the vertical axis represents the descending movement distance of the crosshead or piston. FIG. 3 is a vertical cross-sectional front view showing an enlarged operation mode of a piston in a barrel, and FIG. 4 shows a first embodiment employing an encoder as a position detector, showing a relation with a crosshead. FIG. 5 is a perspective view showing a second embodiment in which a linear sensor is used as a position detector and is a front view showing the relationship between the crosshead and the linear sensor. FIG. 6 shows the prior art. 10 …… barrel, 11 …… furnace body, 12 …… sample, 12A …… molten polymer, 13 …… piston, 18 …… load cell, 20 ……
Computer, 21 …… Crosshead, 22 …… Parallel rod,
23 …… Extrusion motor, 26 …… Position detector, 38 …… Plotter

Front Page Continuation (72) Inventor Hiroyuki Matsumoto 1-1 Anezaki Kaigan, Ichihara-shi, Chiba Idemitsu Petrochemical Co., Ltd. In-house (56) Reference JP 57-13336 (JP, A) JP 57-45430 (JP, A) JP 48-46374 (JP, A)

Claims (3)

[Claims] 1. A barrel provided with a capillary for receiving a piston and a sample by the descending movement of the crosshead, which is caused by descending movement of the crosshead in which a piston is connected downward by a program setting in a computer, as the time elapses. The first step of degassing, the second step of pre-extruding by lowering movement of the crosshead, and the third step of performing main measurement by lowering movement of the crosshead. The crosshead moving distance and the relaxation time are selected in advance in a desired manner so that the descending speed of the crosshead gradually changes from high speed to low speed or from low speed to high speed, and the position of the crosshead moving and descending. Detecting the load and inputting the position detection signal to the computer, the load on the sample is detected and the load detection signal is detected. While inputting to the computer and processing the measured data by the computer to output to a plotter, if the descending speed of the crosshead is from high speed to low speed, the relaxation time is provided for each speed, And the automatic test method in the capillary type flow characteristic test device, which is the end of the main measurement when the crosshead descends to the position set in the computer 2. In the above first step, safety measures are taken to stop the operation when the load exceeds the set value, and in the second step, the flow stabilization of the sample is performed, and in the subsequent third step of the main measurement. By performing a preliminary action to enhance the reproducibility of the measurement, and in the third process, the end of this measurement is determined by the movement position of the crosshead, so that various types of samples with a wide range of viscoelastic properties can be safely and accurately measured. An automatic test method in a capillary type flow characteristic test device according to claim 1, which is configured to be measurable. 3. A program is set in a computer to move a crosshead having a piston downwardly connected downward to move the gas to degas a barrel in which a piston and a sample are received and which has a capillary. When performing pre-extrusion and main measurement, the speed and speed at which the computer (20) operates
The motion control section (24) is connected to the extrusion motor (23), and the reduction gear system (22A) is provided between the extrusion motor (23) and the crosshead (21) which connects the piston (13) downward.
The cross head (21) with the parent screw (22) interposed.
According to a preset program, the moving position of the crosshead (21) is detected by a position detector (26) having a mechanism interlocking with this movement, and the position detection signal (I) is detected as described above. Computers (20)
The load detection signal (K) detected by a load detector such as a load cell (18) or a pressure detector (25) that detects the load on the sample (12) while inputting to the computer (20). Enter the computer (2
Automatic test equipment in the capillary type flow characteristic test equipment for processing measurement signal data in 0) and outputting it to the plotter (38)