JPH0495875A - Compression test device - Google Patents

Abstract

PURPOSE:To measure very accurately even at a temperature condition of 300 deg.C or higher by providing the upper side of a heating cylinder with a cooling system and forming the filling resin between a moving piston and a pressure cylinder into a molten state or a viscous state. CONSTITUTION:A cooling system 26 is set up near the opening of a heating cylinder 24 inserting a moving piston 30 and the filling resin 35 filled between the piston 30 and a pressure piston 34 is formed continuously from a molten state to semimolten state due to the heating by a lower heater 25 and the cooling by the upper system 26. While a pressure-temperature sensor 36 watching the pressure of the upper portion of the piston 30 is set up at the side of the cylinder 24, the piston 30 is made a position control independent of the piston 34 because a piston rod 31 of the piston 30 is supported through the screw of a screw seat 33. The pressure of a sample 3 is made by pushing the piston 34 into the cylinder 24, the position of the piston 30 is adjusted while sensors 2 and 36 are watching, and the leak of the measuring part is being restrained, the pressures of both the sensors being made equal. Thus, the highly accurate measurement can be made.

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention provides a method for determining specific volume based on changes in pressure and temperature of resin.
Or it relates to a compression test device for measuring changes in density.

[Conventional technology]

Generally, as a compression test device for measuring the pressure-volume-specific volume or density relationship of molten resin, a simple method in which a resin sample sealed in a closed cylinder is compressed with a piston is widely used. In this device, since the relative displacement between the piston and the cylinder is verified, resin leakage between the two must be prevented. However, it is extremely difficult to prevent leakage of resin whose viscosity has decreased under high temperature and high pressure. The cause of resin leakage is the pressure difference between the pressure of the sample being compressed and the external force, and the gap between the sliding parts of the piston.Since the gap cannot be made completely zero due to the structure, there are no other methods other than reducing the pressure difference mentioned above. There is no.

Conventionally, as a method for solving such problems, a compression testing apparatus as shown in FIG. 2 has been proposed. this is,
Journal of the Society of Plastic Molding Processing, “Molding Processing J, JS
P' 89 Tech, Paper P125~
126. In the figure, a cylinder 1 equipped with a heater 7 has its lower end covered with a pressure/temperature sensor 2, and a hole 8 is provided on the side for sucking air inside the heating cylinder. (not shown). This is a double piston system in which a resin measurement sample 3 filled in a cylinder is sealed with a movable piston 4, and an elastic sealing material 5 is interposed between the movable piston 4 and the pressurizing piston 6. The pressurizing piston 6 is moved up and down by a fluid pressure cylinder (not shown) or the like via a flange 10 having a heat insulating material 9 sandwiched therebetween. 12 is a jig to which the sensor 2 is fixed.

In the measurement using the conventional compression test device, for example, when measuring polypropylene resin, sample 3 is filled into the heating cylinder l, and the sensor 2 and heater 7
Heating is controlled to a predetermined temperature of 0°C to 250'C. At the same time, after the air inside the cylinder 1 is sucked by a vacuum pump, it is sealed by a movable piston 4, and an elastic sealing material 5 made of fluororubber and a pressurizing piston 6 are further inserted. Thereafter, by pushing the pressurizing piston 6 into the heating cylinder 1 at a set pressure of 20 to 2000 atmospheres, the molten sample 3 is compressed via the elastic sealing material 5 and the movable piston 5. At this time, the movable piston 4
is independent from the pressure piston 6 and is not fixed anywhere, so it naturally moves to a position where the pressure of Example 3 and the pressure of the elastic sealing material 5 are approximately balanced. Here, the pressure and temperature of the sample 3 are determined from the sensor 2, and the volume is determined from the relative displacement between the movable piston 4 and the cylinder 1. Movable piston number and cylinder 1 (inner diameter 8.5mm)
And, the clearance on one side between the pressurizing piston 6 and the cylinder l is 4 each.
μm is 112 μm.

FIG. 3 shows an example of measurement results obtained with this compression testing device. In the figure, the horizontal axis represents temperature, and the vertical axis represents specific volume.9 The temperature dependence of specific volume at each set pressure is shown.

In the above-mentioned conventional compression test apparatus, the pressurizing piston 6 and the sample 3
By interposing the elastic sealing material 5 between 0 and 0, the sealing effect due to the deformation of the elastic body and the problem of the pressure difference mentioned above can be solved. The aim is to prevent resin leakage by causing the transition to occur.

[Problem to be solved by the invention]

In the conventional compression test equipment as described above, the elastic seal material 5
There is a problem in that the sealing performance deteriorates due to deterioration of the elastic body at high temperatures, and the measurement temperature conditions are limited by the heat resistance of the elastic sealing material 5. In the case of fluororubber, it is difficult to measure at temperatures above 300'C.

The present invention has been made to solve the above problems, and aims to provide a compression testing device that can perform measurements with high accuracy under temperature conditions of 30° C. or higher.

[Means to solve the problem]

The compression testing device according to the present invention installs a cooling device near the piston insertion port of the heating cylinder, and performs heating and cooling in parallel to create a semi-molten or highly viscous material between the movable piston and the pressurizing piston. This type of resin is filled with resin.

Furthermore, a pressure sensor for monitoring the pressure above the movable piston is attached to the side surface of the cylinder, and a mechanism for controlling the position of the movable piston independently of the pressurizing piston is provided.

[Effect]

In this invention, while pushing the pressurizing piston into the cylinder, the position of the movable cylinder is controlled independently from the pressurizing cylinder, thereby equalizing the pressure of the sample and the pressure of the adjacent filling resin across the movable piston. At the same time, the sample is compressed and measured.

〔Example〕

FIG. 1 is a front view showing a compression testing apparatus according to an embodiment of the present invention, with main parts cut away. In the figure, 20 is a base plate to which four pillars 21 are fixed. 22 is a lower fixed plate, 23 is an upper fixed plate, and 24 is a heating cylinder, a heater 25 is attached to the lower side circumference, and a cooling device 26 is attached to the upper side circumference. 2F is a lifting device attached to the fixed plate 22, for example, a fluid pressure cylinder, a piston rod 27a, etc.
is being served. 2B is a movable receiving plate fixed to the piston rod 27a, and 29 is a sensor fixing jig supported on the movable receiving plate 28, which fixes the pressure/temperature unit 2.
It supports the heating cylinder 24. A movable piston 30 is inserted into the heating cylinder 24 and pressurizes the resin measurement sample 3 downward. The piston rod 31 taken out from the movable piston 30 passes through the upper fixed plate 23 and
It is supported by passing a screw through a screw seat fixed to the holder, and is manually rotated and moved up and down by a handle 32 fixed to the upper end.

The piston rod 31 may be rotated manually using the handle 32, or may be driven by an electric motor or the like. 34 is a pressurizing piston whose lower part is inserted into the heating cylinder 24;
The upper end is received by the upper fixed platen 23. Reference numeral 35 is a filling resin made of the same material as the measurement sample 3, which is filled between the movable piston 30 and the pressurizing piston 34, and continuously changes from a molten state to a semi-molten state by heating downward and cooling upward. A pressure/temperature sensor 36 for monitoring the pressure/temperature of the filling resin 35 in the upper part of the movable piston 4 and a temperature sensor 37 for monitoring the temperature of the cylinder 1 itself are attached to the side of the heating cylinder 24. ing.

A hole 8 is provided in the side of the heating cylinder 24, and a pipe fitting 11 is provided in the side of the heating cylinder 24.
It is connected to a vacuum pump (not shown) via a vacuum pump (not shown) to suck the air inside the cylinder.

Reference numeral 38 denotes a displacement measuring device supported by the movable receiving plate 28, which measures the relative displacement between the cylinder 24 and the movable piston 30 by moving the interlocking body 39, which is in contact with the handle 32 of the piston rod 31 and transmits upward and downward movements, up and down. .

In the compression test apparatus of the above embodiment, when measuring polypropylene resin, for example, the heater 25
The heating cylinder 24 is heated to a predetermined temperature of 00 to 250°C, and the temperature is increased to 9100°C by the piston insertion port side cooling device 26.
Cool below. At this time, it is preferable that the resin temperatures indicated by the cell/cell 2 and the sensor 36 are the same. The sample 3 is pressurized by raising the heating cylinder 24 itself using the lifting device 27 and pushing in the opposing pressure piston 34. At the same time, the position of the movable piston 30 is adjusted while monitoring the sensor 2 and the sensor 36. The adjustment ensures that the pressures indicated by both sensors are always approximately equal. in this way,
By eliminating the pressure difference between the measurement sample 3 and the filling resin 35 above the movable piston 30, leakage from the measurement section is suppressed. In addition, even if the resin is in a molten state near the cooling section and resin leaks from the sliding part of the pressure piston 34,
If it is a microtubule, there will be no problem in measurement.

Although the above embodiment shows a case where the same filling resin 35 as the measurement sample 3 is interposed between the movable piston 30 and the pressurizing piston 34, it is also possible to use another resin having a temperature different from that of the sample to form a molten state. Alternatively, a lubricant may be added. Preferably, the resin has a higher viscosity than the measurement sample at the same temperature.

By the way, in the above embodiment, the case where the relationship between pressure-temperature-specific volume or density of the resin was measured was described, but when measuring other characteristics of the resin, 4. It is applicable.

〔Effect of the invention〕

As described above, according to the present invention, a cooling device is attached to the upper side of the heating cylinder, and the filling resin between the movable piston and the pressurizing cylinder is formed in a molten state or a high viscosity state. This has the effect of suppressing leakage and allowing accurate measurement of the pressure-temperature-specific volume or density relationship of the resin.

[Brief explanation of the drawing]

FIG. 1 is a front view of a main part of a compression test apparatus according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of a conventional compression test apparatus, and FIG. It is a characteristic diagram showing a relationship. 2...Pressure/temperature sensor%3...Measurement sample, 22.
・Lower fixed plate, 23-・Upper fixed plate, 24... Heating cylinder, 25... Heater, 26... Cooling device, 27.
... Lifting device, 28... Movable receiving plate, 30... Movable piston, 31... Piston rod, 34... Pressure piston, 35... Filling resin, 36... Pressure-temperature sensor , 37... Temperature sensor, 38... Displacement measuring device, 3
9... Interlocking body Note that the same reference numerals in the drawings indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] A heating cylinder in which a resin measurement sample of a predetermined weight is sealed in the lower part, the lower part is heated by a heater to adjust the temperature, and the upper part is cooled by a cooling device; The molten sample near the heating section is sealed, the piston rod is placed above the movable piston in the heating cylinder, and the sample is continuously changed from a molten state to a semi-molten state, or from a low viscosity to a high viscosity. The filling resin is in a viscous state, the upper end is received by the upper fixed plate, the lower end is a pressurizing piston that compresses the filling resin in the heating cylinder from above, and the movable piston is connected to the heating cylinder via the piston rod. means for moving up and down against the
A lifting device that is attached to the lower fixed plate and raises and lowers the heating cylinder via a movable receiving plate, and is supported by the movable receiving plate, and the vertical movement of the piston rod is transmitted via the interlocking body, and the displacement of the movable piston with respect to the heating cylinder. a first pressure/temperature sensor disposed at the lower end of the heating cylinder to measure the measurement sample in the cylinder; and a first pressure/temperature sensor mounted on the side of the heating cylinder to detect the filling in the heating cylinder. A second pressure/temperature sensor is provided to measure the lower side of the resin, and the movable piston is pressurized so that the pressure of the measurement sample and the pressure of the semi-molten filled resin adjacent to the movable piston are equal. A compression testing device characterized in that the position is controlled independently of the piston.