JPH0690160B2 - Specific volume change measuring device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a specific volume change measuring device for measuring a specific volume change of a sample to be measured with respect to a change in temperature or pressure, using a polymer material as a sample to be measured.

[Prior Art] A molding process of a polymer material is processed by a series of steps of shaping a predetermined shape in a heating and melting state and then cooling and solidifying the same, but with a change in temperature and pressure during the step, It is known that the volume of the material also changes. Knowing the change in specific volume (volume per unit mass) of the polymer material at this time has an important meaning for determining the dimensions of the final product. Therefore, there is a need for a specific volume change measuring device that can easily and accurately measure the specific volume change characteristics of polymer materials due to pressure and temperature changes.

Conventionally, as a specific volume change measuring device of this kind, there has been one having a configuration as shown in FIGS. 6 (a) to 6 (c). The measuring device A shown in FIG. 3A was developed as a research machine at the Aachen University of Technology in West Germany. The sample S to be measured, which was previously processed into a cylindrical shape, was inserted into the cylinder 100, and the sleeve 101 was inserted from above. In this way, the inside of the cylinder 100 is hermetically closed, a pressure is applied to the sample S to be measured, and the temperature is changed by the temperature adjusting means 102 provided around the cylinder, so that the volume change of the sample S to be measured is examined. (POLIMER ENGINEERING AND SCIENCE, OC
TOBER, 1977, Vol.17, No.10, P758-763).

The measuring device B shown in FIG. 2B is disclosed in Japanese Utility Model Laid-Open No. 19963/1985, in which a sample S to be measured which has been previously processed into a cylindrical shape is inserted into the cylinder 110 and is applied from above. The pressure member 111 is fitted to seal the inside of the cylinder 110.
Then, the upper surface of the pressure member 111 is pressed by another pressure member 112 to exert a pressure on the sample S to be measured, or the temperature is changed by the heater 113 provided around the cylinder, and the pressure member at that time is changed. The displacement of 111 measures the specific volume change of the sample S to be measured.

The measuring device C of FIG. 7C is disclosed in Japanese Utility Model Laid-Open No. 62-167165, in which a mercury S122 is stored together with the sample S to be measured in a container 120 equipped with a bellows 121 which is elastic at the lower end. Fill. An oil filling chamber 123 communicating with a pressure pump (not shown) is provided around the container 120 via a passage,
By changing the oil pressure in the oil filling chamber 123, the pressure in the container 120 is changed via the bellows 121. A coil pipe 124 is provided in the oil filling chamber 123, and by heating or cooling oil circulated in the coil pipe 124, the temperature in the container 120 is changed via the oil in the oil filling chamber 123. Let The container 120 is then measured by measuring the expansion and contraction of the bellows 121.
It is configured to detect a change in volume of the sample S to be measured with respect to a change in internal pressure or temperature.

[Problems to be Solved] Each of the above-described conventional specific volume change measuring devices has the following problems.

Both the measuring device A and the measuring device B are configured to seal the inside of the cylinder by inserting a sleeve (pressurizing member). However, in such a simple fitting structure, the sample to be measured has a bottom viscosity of When a high pressure is applied to the melt, the melt may leak from the fitting portion between the cylinder and the sleeve, and a highly accurate measurement result cannot be expected.

As described above, the measuring device A and the measuring device B cannot suck the inside of the cylinder under vacuum due to the poor tightness of the inside of the cylinder. As a result, the error of the specific volume due to the holes in the sample to be measured is removed. Therefore, the sample to be measured must be processed in advance into a cylindrical shape that matches the internal shape of the cylinder, which lacks in ease.

Since the measuring device C has a structure in which the bellows are expanded and contracted by hydraulic pressure to adjust the pressure, strict control of the amount of oil is required at the time of measurement, and the operation is complicated.

Further, since the measuring device C uses mercury as a medium, there is a risk of mercury leaking out when an abnormality such as a device failure or damage occurs, which is a problem in terms of safety and hygiene.

The present invention has been made in consideration of the above problems,
By preventing the melt from leaking under high pressure, it is possible to measure the specific volume change from the solid state at low temperature to the molten state at high temperature without pretreatment of the measured sample. It is an object of the present invention to provide a safe and hygienic specific volume change measuring device that can be easily and highly accurately performed.

[Means for Solving Problems] In order to achieve the above object, the present invention relates to a specific volume measuring apparatus for measuring a change in specific volume of a sample to be measured with respect to a change in temperature or pressure. A holder having a hollow portion, a pressure punch that is fitted into the hollow portion of the holder, a float that slidably penetrates through the pressure punch in the axial direction, and a hollow portion of the holder that slides without gaps. A pressure plate attached to the tip of the float, which is in contact with and one surface of which contacts the sample to be measured, and a seal made of an elastic body or a viscoelastic body, which is provided between the tip surface of the pressure punch and the pressure plate. It is configured to include a member and means for detecting the displacement of the float.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a front sectional view showing a specific volume change measuring device according to an embodiment of the present invention, and FIG. 2 is a side sectional view showing a degassing operation.

In these drawings, reference numeral 1 denotes a cylindrical holder having a hollow portion 1a having an open upper end. The pressure / temperature sensor 2 is fitted in and closed at the lower end opening of the hollow portion 1a. As shown in FIG. 2, a hole (vacuum suction hole) 3 for vacuuming is formed in the upper part of the side wall of the holder 1, and a pipe 4 connected to a vacuum pump (not shown) can be connected. . The sample S to be measured can be accommodated from the upper end opening of the hollow portion 1a, and the rod-shaped pressure punch 5 can be fitted therein.

The pressurizing punch 5 has a diameter that is in sliding contact with the hollow portion 1a of the holder 1 without a gap and a length that is substantially the same as the length of the holder hollow portion 1a. A central hole 5a is formed in the central shaft portion of the pressure punch 5 so as to penetrate from one end to the other end.

The float 6 has a rod-shaped float body 6a that is longer than the entire length of the pressure punch 5 by a certain length, and the float body 6a is inserted through the center hole 5a of the pressure punch 5. Float body 6a
A disk-shaped pressure plate 8 having a diameter that makes sliding contact with the hollow portion 1a of the holder 1 without a gap is coaxially attached to the tip of the. The pressure plate 8 is fitted into the hollow portion 1a of the holder 1 together with the pressure punch 5.

On the other hand, a metal reference plate 9 serving as a reference for detecting the float height position is attached to the base end of the float body 6a.

Further, a screw which is screwed with the nut 7 provided on the upper end of the pressure punch 5 is formed in a part of the float body 6a,
The nut 7 is screwed together when the hollow portion is degassed. By fixing the nut 7 to the float 6 as described above, even if the hollow portion 1a is evacuated during degassing, only the float 6 (pressurizing plate 8) will not be lowered.

Further, between the tip surface of the pressure punch 5 and the pressure plate 8,
A seal member 10 made of an elastic body or a viscoelastic body is provided. The seal member is preferably made of a material having heat resistance such as silicone rubber, fluororubber, and acrylic rubber. Further, a thermoplastic resin such as polyethylene, polypropylene, polyester, polystyrene, polyamide, or polycarbonate can also be used. When a solid viscoelastic body is used as the seal member 10, the holder 1
The hollow portion 1a is given a diameter to be fitted in a compressed state. Further, as the seal member 10, a liquid having high viscoelasticity, liquid rubber, or the like may be used.

In FIGS. 1 and 2, 20 is a temperature control station 21.
And a base on which the degassing station 22 is provided. The stations 21 and 22 of the base 20 are provided with mounting holes 23 and 24 for fixing the holder 1 by fitting the pressure / temperature sensor 2 therein.

The temperature control station 21 is provided with a temperature adjusting means and heats or cools the holder 1 fixed in the mounting hole 23 from the surroundings. That is, a cylindrical heating / cooling device 25 having an inner diameter slightly larger than the outer diameter of the holder 1 is provided around the mounting hole 23, and the outer periphery thereof is covered with a heat insulating material 26. The heating / cooling device 25 includes a coiled pipe for circulating heating or cooling oil, an electric heater (when only heating is required), a cooling tube (when only cooling is required), or any other known heating method. -A cooler can be applied.

In FIG. 1, reference numeral 30 denotes a non-contact type displacement gauge, which is provided above the temperature control station 21 and measures the height position of the reference plate 9 attached to the float 6 attached to the station 21. As the displacement meter 30, various known non-contact type displacement sensors such as an eddy current type displacement sensor and an air micro type displacement sensor can be used.

Next, a method of measuring the specific volume change of the polymer material with respect to the temperature / pressure change using the above-mentioned specific volume change measuring device will be described.

First, the holder 1 is attached to the degassing station 22, and the sample S to be measured is inserted into the holder hollow portion 1a. The sample S to be measured need not be subjected to a pretreatment for matching the shape of the holder hollow portion 1a, which has been conventionally required, and may be inserted in a granular form.

Next, the pressurizing punch 5 with the float 6 and the seal member 10 fitted therein is inserted from the opening of the holder hollow portion 1a, and the pressurizing plate 8 is inserted.
The pressurizing punch 5 is arranged at a position where the lower surface thereof is slightly above the position where the vacuum suction hole 3 is formed. Then, the float 6 is pulled up relative to the pressure punch 5, and the seal member 10 is crushed between the tip surface of the pressure punch 5 and the pressure plate 8 to seal the inside of the hollow portion 1a of the holder 1. . In this state, the pipe 4 is connected to the vacuum suction hole 3 and the gas in the holder hollow portion 1a is released by a vacuum pump (not shown) (see FIG. 2).

After the gas is sufficiently degassed, the pressure plate 8 moves to the sample S to be measured.
Pressurization punch 5 is lowered until it is connected to
Is removed from the vacuum suction hole 3 and the holder 1 is mounted on the temperature control station 21 (see FIG. 1). From this state, the change in specific volume of the sample S to be measured with respect to the change in temperature or pressure is measured.

The change in specific volume with respect to temperature change is measured as follows. That is, the pressure applied by the pressure punch 5 is kept constant, and the heating / cooling device 25 is operated to change the temperature of the sample S to be measured. Then, the pressure and temperature are measured by the pressure / temperature sensor 2, and the displacement of the reference plate 9 at each measurement point is measured. Since the reference plate 9 moves up and down in response to a change in the volume of the sample S to be measured inserted in the holder 1, the displacement amount of the reference plate 9 is converted into a volume,
The change in the specific volume can be obtained by dividing by the weight of the sample S to be measured that has been measured in advance.

To measure the change in specific volume with respect to the change in pressure, the temperature inside the holder 1 is kept constant, the pressing force of the pressure punch 5 against the sample S to be measured is changed, and the displacement of the reference plate 9 at each measurement point is measured. The change in the specific volume is obtained in the same manner as in the case of the temperature change.

3 (a) and 3 (b) are views for explaining the structural features of the above-mentioned specific volume changing device, and FIG. 3 (a) corresponds to the device of the conventional device (FIG. 6 (b)). (B) is a schematic configuration diagram of the device according to the present embodiment.

As shown in FIG. 3A, the punch 114 is used in the conventional device.
It is necessary to prevent resin leakage from the sliding contact portion 115a while allowing relative sliding between the holder 115 and the holder. However, when the sample to be measured has a low viscosity under high pressure or high pressure, the pressure difference between the internal pressure P ₁ of the holder 115 and the atmospheric pressure P ₀ acts on the sliding contact portion 115a as it is. Is difficult to prevent.

On the other hand, the specific volume changing device of the present embodiment is shown in FIG.
As shown in FIG. 3, since the pressing plate 8 and the seal member 10 made of an elastic body or a viscoelastic body are interposed between the inside of the holder 1 and the outside, the sample pressure P ₁ is gradually increased through the viscoelastic body pressure P _2. The pressure shifts to atmospheric pressure P _0, and the pressure difference between P _{1 and} P ₂ becomes small. Therefore, the airtightness is improved and the resin leakage can be prevented.

As a result of the improved hermeticity, the gas in the holder 1 can be extracted by vacuuming before measurement.
It is not necessary to match the sample to be measured with the holder shape in advance.

FIG. 4 is a front sectional view showing another embodiment of the present invention.

In the previous example, as shown in FIG. 2, the gas in the holder 1 was removed by vacuum suction before the measurement, but in this example, the solid sample S to be measured S in the holder 1 was removed. With
By filling a low-viscosity liquid L such as water or oil as a medium, excess gas in the holder 1 is removed.
In the present invention, since the hermeticity is improved as described above, even if the low-viscosity liquid (medium) L is filled, it does not leak.

Further, since the liquid is the medium, there is no possibility that the sample and the pressure plate will stick to each other even when the sample is cooled from the molten state and solidified.

[Example] As a test device, the holder and punch were hardened tool steel SKD11
The measurement was performed on a holder having an inner diameter of 8.5 mm. The conditions are shown below.

Specimen: Idemitsu Styrol US300 Seal member: Fluorine rubber Sample weight: 1.208 g The measurement results are shown in FIG.

By using this device, it became possible to measure data in the temperature range from the molten state to the solid state in a wide pressure range of 0 to 2400 (kg / cm ² ).

[Effects of the Invention] As described above, according to the specific volume change measuring apparatus of the present invention, the pressure plate and the seal member made of a viscoelastic body are interposed between the inside and the outside of the holder. It is possible to prevent the melt from leaking out, and measure the specific volume change of the measured sample from the solid state at low temperature to the molten state at high temperature easily and accurately without the need for pretreatment of the sample to be measured. can do.

Further, since the structure is such that the pressure is changed by the piston method using the holder and the punch, the measurement management is simple, and further, since mercury is not used, it is safe and hygienic.

[Brief description of drawings]

FIG. 1 is a front sectional view showing a specific volume change measuring device according to an embodiment of the present invention, FIG. 2 is a side sectional view showing a degassing operation, and FIGS. 3 (a) and 3 (b) are structures of the device. FIG. 4 is a schematic sectional view for explaining the above features, FIG. 4 is a front sectional view showing another embodiment, FIG. 5 is a graph showing experimental results, FIG. 6 (a),
(B), (c) is a front sectional view showing a conventional device, respectively. 1: Holder 2: Pressure / temperature sensor 3: Vacuum suction hole 5: Pressurizing punch 6: Float 8: Pressurizing plate 9: Reference plate 10: Seal member 25: Heating / cooling device 30: Displacement meter

Claims (1)

[Claims] 1. A specific volume measuring device for measuring a change in specific volume of a sample to be measured with respect to a change in temperature or pressure, wherein a holder having a hollow portion for enclosing the sample to be measured, which is open at one end, and a hollow portion of the holder. The pressurizing punch to be inserted, the float that is slidably provided by penetrating the pressurizing punch in the axial direction, and the float that is in sliding contact with the hollow portion of the holder without a gap and has one surface in contact with the sample to be measured. A pressure plate attached to the tip of, a sealing member made of an elastic body or a viscoelastic body provided between the tip surface of the pressure punch and the pressure plate, means for detecting the displacement of the float, A specific volume change measuring device comprising: