JP2539743B2 - Method and apparatus for measuring pressure-volume-temperature characteristics in material - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for measuring a pressure-volume-temperature relationship (hereinafter abbreviated as PVT characteristic) in a material, and particularly to a resin or the like as an object to be measured. The present invention relates to a measuring method and an apparatus for an indirect method, which is suitable for the case where the measurement is performed using a sample cell.

[0002]

2. Description of the Related Art In the technical field of molding thermoplastic and thermosetting resins, in recent years, flow analysis and mold design by computer simulation have been extensively carried out. The PVT characteristic of a resin is an important data which is the basis of the computer simulation, but the PVT measuring device used for the acquisition is required to be improved so as to facilitate the handling of a sticky sample. .

Regarding an apparatus for measuring the PVT characteristics of a material by using an indirect method using a sample cell, a report by Sato et al. (Sato et al., Proceedings of the 3rd Annual Meeting of the Japan Society for Plastic Molding Processing, p. 172), Ogizawa There are reports (Ogizawa, 3rd Annual Meeting of the Japan Society for Plastic Molding Processing Proceedings 177 pages). The sample cell in these devices is a sample to be measured alone, or a sample and mercury are sealed therein, and a change in cell internal volume at a desired temperature and pressure can be measured as expansion and contraction of a bellows. The sample cell in the former device measures the increase in cell volume as the elongation of the bellows, and the sample cell in the latter device is
The increase in cell volume is measured as the contraction of the bellows. In each case, the tip of the rod connected to the movable part of the bellows is connected to the core of the differential transformer, and its displacement is measured. .

When such a device is used to measure the PVT characteristics of a thermosetting synthetic resin, the cured resin adheres to the upper part of the sample cell, making it difficult to reuse the sample cell and If the cell is fixed to the expansion / contraction part, the expansion / contraction part of the cell is prevented from freely expanding and contracting, the expansion / contraction amount does not accurately represent the change in the internal volume of the cell, and the cell may be damaged. Further, when it is used for measuring the PVT characteristics of a thermoplastic synthetic resin, the molten resin may be solidified by cooling and may cause the same problem. Furthermore, when weighing a liquid sample, the weight difference between the cells before and after the sample is sealed is measured.However, since the weight of the sample cell made of metal is large, it is difficult to weigh accurately. there were.

[0005]

SUMMARY OF THE INVENTION The technical problem of the present invention is to provide means for measuring the above-mentioned fear-free PVT characteristics, and more specifically, that the material to be measured is cured. Even if there is, there is no sticking in the sample cell, thereby facilitating the reuse of the sample cell and measuring the sample with high accuracy. To provide a device.

[0006]

A method for measuring PVT characteristics of the present invention for solving the above problems is to seal a sample to be measured, or a sample and a liquid having a known compressibility, in a sample cell. When measuring the pressure-volume-temperature characteristics from the change in the cell internal volume depending on the temperature and pressure, the sample to be measured has a communication passage that communicates the inside and outside,
Cover the communication passage and keep the sample floating inside.
It is characterized in that it is accommodated and handled in a sample capsule provided with a cap portion having a holding area .

Further, the PVT characteristic measuring device of the present invention is
Equipped with a sample cell to enclose the sample to be measured, or a liquid of that sample and a known compressibility, at the desired temperature,
In a measuring device for measuring PVT characteristics from changes in cell internal volume under pressure, the sample cell is loaded with a sample capsule for accommodating a sample to be measured, and the capsule has a communication passage communicating with the inside and the outside. Or
Cover the communication passage and keep the sample floating inside.
The present invention is characterized in that a cap portion having a holding area is provided . In the above device, the sample capsule is composed of a cup portion and a cap portion, and the cap portion is attached to the cup portion with a gap between them to secure a communication passage inside and outside the capsule , Cap
It is possible to have a structure in which a floating sample holding area is formed in the cap portion , and the sample capsule can be made of a thin metal.

[0008]

In measuring PVT characteristics, the weight of a sample such as a thermosetting resin can be measured by placing it in a thin metal capsule and weighing it. In this case, the weight of the capsule is the sample. The weight of the sample is very small compared to the weight of the cell, so that the weight of the sample can be weighed with high accuracy. Next, the Kabucell is loaded into the sample cell and a liquid of known compressibility is enclosed in the sample cell,
In this case, even if the sample floats upward due to buoyancy,
Because it stays in the retention area inside the capsule cap ,
The sample does not adhere to the inner wall of the sample cell. In addition, even if the resin or the like of the sample is cured while the sample cell is set in the PVT measuring device and is measured, it remains in the holding area in the cap portion of the capsule and is cured, so that the inner wall of the sample cell and the sample By adhering to the stretchable part of the cell and curing, it does not cause difficulty in reuse of the sample cell and deterioration of the measurement accuracy of the internal volume, and after the measurement is completed, the sample is stored in the capsule as it is. It can be easily removed from the cell. The specific volume of a sample under desired temperature and pressure conditions is measured as a change in the internal volume of the sample cell.

[0009]

EXAMPLE FIG. 1 shows an example of a PVT characteristic measuring apparatus according to the present invention. This measuring device determines the P of the material from the change in the internal volume of the cell under the desired temperature and pressure conditions.
For measuring VT characteristics, a pressure vessel 1 is provided with a sample cell 2 for enclosing a sample to be measured, or the sample and a liquid having a known compressibility such as mercury. The pressure vessel 1 is connected to a plunger pump 4 for maintaining the inside and outside of the sample cell 2 in a pressurized state at its pressure inlet 3, and the pressure detected by the pressure sensor is fed back to the plunger pump 4 to provide a pressure. A heating device 5 that is controllable and that controls the temperature condition inside the pressure vessel 1 is disposed.

The sample cell 2 has a capsule 2 inside.
The upper end of the tubular body 6 having the locking portion 7 of 0 is closed by the lid 8 and the lower end is closed by the bellows 9, and the rod 10 connected to the movable portion of the bellows 9 is led out downward.
The tip of the rod 10 is connected to the core 12 of the differential transformer 11 attached to the lower part of the pressure vessel 1, and the change in the internal volume of the sample cell 2 is measured as the displacement of the core 12 due to the expansion and contraction of the bellows 9. .

In order to detect the internal temperature of the pressure vessel 1, a thermocouple 15 inserted from the upper portion of the pressure vessel 1 is erected in the center of the upper lid 8 of the sample cell 2 to form a pipe 13.
And guides the tip thereof to the upper packing 14 in the lid 8. Sample cell 2
The pressure and temperature and the displacement of the core of the differential transformer are configured to be recorded by a recorder and loaded into a computer for analysis.

As shown clearly in FIG. 2, the sample capsule 20 for containing the sample to be measured comprises a cup portion 21 and a cap portion 22, which are made of thin stainless steel (18-8Cr-Ni) or the like. It is made of thin metal. In this capsule 20, a part of the cap portion 22 (three places at regular intervals) is cut and raised inward to form an elastic protrusion 23, and the elastic protrusion 23 is formed into the cup portion 2.
By making pressure contact with the peripheral surface of No. 1, the cap portion 22 is attached to the cup portion 21 with a gap 24 therebetween, and a communication passage inside and outside the capsule is secured. Also, the cap portion 2
2 forms the communication passage so as to cover it and
It forms a holding area that can hold the floating sample.
In this capsule 20, the rim of the cap portion 22 is placed on the locking portion 7 on the inner surface of the cylindrical body 6 of the sample cell 2 and loaded in the sample cell.

In the capsule 20, since the cap portion 22 is attached to the cup portion 21, the sample 25 contained in the cup portion 21 as shown in FIG. 2 is replaced by the sample cell 2 as shown in FIG. Even when the mercury 26 floats from the cup portion 21 due to the buoyancy at the time of injecting the mercury 26, it remains inside the cap portion 22 and does not flow out into the sample cell 2. Therefore, the sample 25 made of liquid resin or the like
Can be handled easily, and adhesion of those samples 25 to the inner wall of the cell 2 can be prevented.

In the PVT characteristic measuring device having the above-mentioned structure, when measuring the PVT characteristic, first, a liquid sample 25 such as a thermosetting resin is put in a capsule 20 and weighed.
The weight of the capsule 20 is much smaller than the weight of the sample cell 2, so that the weight of the sample 25 can be weighed with high accuracy. Next, the upper lid 8 of the sample cell 2 is removed and the capsule 20 is loaded into the sample cell. The mercury 26 inlet is opened at the center of the lid 8 and the others are sealed. Fill cell 2 At this time, the resin sample 25 floats upward due to the buoyancy of the mercury 26, but does not flow out of the capsule 20, stays inside the cap portion 22 of the capsule 20, and adheres to the inner wall of the sample cell 2. There is no.

In this sample cell 2, the mercury inlet is sealed by the upper packing 14, the pipe 13 is erected, and then set in the PVT measuring device, and the desired temperature and plan controlled by the heating device 5 are set. The change in the internal volume of the sample cell 2 at the desired pressure controlled by the jar pump 4 is taken as the expansion / contraction amount of the bellows 9 and the rod 10 attached to the bellows.
The specific volume of the sample 25 is measured by detecting the vertical displacement of the core 12 of the differential transformer 11 via, and thereby the PVT characteristic of the sample is measured. During this measurement,
The resin sample 25 stays in the capsule 20 and hardens,
It does not adhere to the inner wall of the sample cell 2 or the bellows 9 and harden. After the measurement is completed, the sample cell 2 is taken out from the PVT measuring device, and the capsule 20 is taken out from the sample cell 2. At this time, since the resin sample does not adhere to the inside of the sample cell, the capsule can be easily taken out.

Next, the measurement results of the specific volume change during the curing process of the epoxy resin will be described with reference to FIGS. 3 and 4. The main agent was bisphenol A diglycidyl ether (Epicote 828, Yuka Shell Co., Ltd.), and the curing agent was diethyltoluenediamine (Ethacure 100, Ethyl Co.). They were mixed at a weight ratio of 100: 24 and vacuum defoamed. Used. Initial value of specific volume (40 ℃, 100 kgf / c
m ² ) was determined by measurement with a pycnometer under atmospheric pressure and compression rate measurement with a PVT measuring device. The internal temperature is also shown in FIG. Fig. 4 is a plot of this against the temperature on the horizontal axis. It is shown that the transition from the glass state to the rubber state occurs at around 95 ° C during the temperature rise from 80 ° C to 180 ° C.
It can be seen that post-cure at 80 ° C rather increases the specific volume at 80 ° C. This indicates that the post-cure cross-linking points hinder the packing of the molecular chains and increase the free volume.

[0017]

According to the PVT measuring method and apparatus of the present invention detailed above, the sample capsule is used in the sample cell so that the sample does not adhere to the inner wall surface of the sample cell or the bellows portion to be cured. Therefore, not only the sample cell can be reused easily, but also the expansion and contraction of the bellows is not obstructed, the sample can be handled easily, and at the same time the measurement accuracy of the internal volume of the sample cell is maintained. The weighing accuracy of can also be improved.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part showing an embodiment of a PVT characteristic measuring device according to the present invention.

FIG. 2 is an enlarged cross-sectional view of a sample capsule.

FIG. 3 is a graph showing a measurement result of a specific volume change in a curing process of an epoxy resin according to the present invention.

FIG. 4 is a graph showing the measurement results of FIG. 3 plotted against temperature on the horizontal axis.

[Explanation of symbols]

 2 sample cells, 20 capsules, 21 cup parts, 22 cap parts, 24 gaps, 25 samples.

Claims (4)

(57) [Claims] 1. A sample cell is filled with a sample to be measured, or a sample and a liquid having a known compressibility, and the pressure-volume-
When measuring the temperature characteristics, the sample to be measured has a communication passage that connects the inside and outside,
And of the sample that covered the communication passage and floated inside
A method for measuring pressure-volume-temperature characteristics of a material, characterized in that the material is housed in a sample capsule equipped with a cap portion having a holding region and handled. 2. A sample cell for enclosing a sample to be measured or a liquid having a known compressibility with the sample,
From the change in the internal volume of the cell at the desired temperature and pressure, the pressure −
In a measuring device for measuring volume-temperature characteristics, the sample cell is loaded with a sample capsule for containing a sample to be measured, and the capsule has a communication passage communicating with the inside and outside , and the communication passage. Together with the lid
The cap part with the holding area for the sample floating inside
An apparatus for measuring pressure-volume-temperature characteristics of a material characterized by being provided . 3. The apparatus according to claim 2, wherein the sample capsule is composed of a cup portion and a cap portion, and the cap portion is attached to the cup portion with a gap therebetween. , The communication path inside and outside the capsule is secured, and the holding area for the sample floating inside the cap is
Pressure-volume-in the formed material characterized
Measuring device for temperature characteristics. 4. The apparatus according to claim 2 or 3, wherein the sample capsule is made of a thin metal, and the pressure-volume-temperature characteristic of the material is measured.