JP7050550B2 - Differential scanning calorimetry - Google Patents

Description

The present invention relates to a differential scanning calorimeter, and more particularly to a differential scanning calorimeter having a function of cleaning a sample container for storing a measurement sample.

The differential scanning calorimeter stores a sample container containing the sample to be measured (measurement sample) and a reference container containing the reference sample (standard sample) or nothing in the furnace, and also uses a heater. By heating both containers at a constant temperature rise rate and detecting the temperature difference between the standard sample being heated and the measurement sample with a temperature sensor such as a thermocouple, the amount of heat released or absorbed by the measurement sample is measured and organic. We collect thermal property data such as thermal behavior such as melting / transition, glass transition, crystallization / oxidation / hardening, dehydration / sublimation of polymer compounds, calorific value and heat absorption (see, for example, Patent Document 1). .).

Japanese Unexamined Patent Publication No. 5-273167

In such a differential scanning calorimeter, the inner surface of the sample container after measurement may be contaminated with sample substances, reaction products, decomposition products, etc. Therefore, the sample container is basically disposable and the number of measurements is repeated. Since the above sample container had to be prepared and the sample container had to be replaced for each measurement, the cost for collecting the thermophysical property data was large.

Therefore, an object of the present invention is to provide a differential scanning calorimeter having a configuration in which a sample container can be efficiently washed after measurement and the sample container can be used repeatedly.

In order to achieve the above object, the differential scanning calorimeter of the present invention includes a furnace body for storing a sample container for storing a measurement sample and a reference container for storing a standard sample, and a heating means for heating the sample container and the reference container. In a differential scanning calorimeter equipped with an atmosphere gas introduction path for introducing a measurement atmosphere gas into a sample container and a reference container, and a temperature measuring means for measuring the temperature of the standard sample and the measurement sample, purge gas is added to the sample container. The purge gas introduction route to be distributed, the sample input route to charge the measurement sample into the sample container, the insertion tube inserted inside the sample container, the cleaning liquid container storing the cleaning liquid, and the rinsing liquid container storing the rinse liquid. A cleaning fluid introduction path having a pump for sending the cleaning solution or the rinsing solution toward the insertion tube, a fluid out-flowing path for deriving the fluid from the sample container, and the fluid during a rinsing operation using the rinsing solution. It is characterized by being equipped with a conductivity meter that measures the conductivity of the rinse drainage derived from the lead-out path.

Further, the differential scanning calorimeter of the present invention is provided with a cleaning liquid return pipe for returning the cleaning waste liquid led out to the fluid lead-out path to the cleaning liquid container during the cleaning operation using the cleaning liquid, and the cleaning liquid is fluorinated. It is a hydrofluoric acid aqueous solution, preferably a hydrofluoric acid aqueous solution containing 0.1 to 1.0% by mass of hydrofluoric acid, and the rinse liquid is pure water. Further, the flow velocity of the cleaning liquid in the sample container is less than 0.63 m / sec, preferably 0.06 to 0.15 m / sec.

According to the differential scanning calorimeter of the present invention, one sample container can be washed and used repeatedly, so that it is not necessary to prepare a dedicated sample container for the number of measurements, and the measurement cost can be reduced. .. In addition, since the same sample container is used, errors due to variations in the heat capacity of the sample container can be eliminated, more accurate and easily comparable data can be collected, and the sample container does not need to be attached or detached, thus improving work efficiency. It can also be improved.

It is a system diagram which shows one form example of the differential scanning calorimetry of this invention.

FIG. 1 is a system diagram showing an example of a form of a differential scanning calorimeter of the present invention. The differential scanning calorimeter shown in this embodiment is a furnace body 13 that stores a sample container 11 that stores a measurement sample and a reference container 12 that stores a standard sample, and a heating means 14 that heats the sample container 11 and the reference container 12. , The atmosphere gas introduction path 15 for introducing the atmosphere gas for measurement into the sample container 11 and the reference container 12, the temperature measuring means 11a and 12a for measuring the temperatures of the standard sample and the measurement sample, respectively, and the purge gas in the sample container 11. The purge gas introduction path 16 to be introduced, the sample injection path 17 for charging the measurement sample into the sample container 11, the insertion tube 18 inserted inside the sample container 11, the cleaning liquid container 19 for storing the cleaning liquid, and the rinse liquid are stored. A cleaning fluid introduction path 21 having a rinse liquid container 20 and a liquid feed pump 21a for sending the cleaning liquid or the rinse liquid toward the insertion tube 18, a fluid lead-out path 22 for deriving the fluid from the sample container 11, and a rinse liquid. It is equipped with a conductivity meter 23 for measuring the conductivity of the rinse drainage discharged from the fluid out-flow path 22 during the rinse operation using the above, and an on-off valve or a three-way switching valve provided at a predetermined position in each path. It has a bypass route. In addition, some routes are standardized, and the common route is switched and used by opening and closing the on-off valve and switching the three-way switching valve.

Next, the configuration of the differential scanning calorimeter will be described in more detail based on the operating procedure. At the start of the operation, each on-off valve is in the closed state, each three-way switching valve is switched in the linear direction in FIG. 1, and the sample container 11 and the reference container 12 are new. Further, the reference container 12 is used in an empty state without storing the standard sample.

First, the sample charging valve 31 of the sample charging path 17 is opened, and a predetermined amount of the sample for which data is to be collected is charged into the sample container 11 via the three-way switching valves 32 and 33. Next, the three-way switching valve 32 is switched in the direction of the atmospheric gas introduction path 15, and the three-way switching valve 34 of the fluid lead-out path 22 is switched in the direction of the purge exhaust path 22a branched from the fluid lead-out path 22.

Then, the atmosphere gas introduction valve 35 of the atmosphere gas introduction path 15 connected to the atmosphere gas source (not shown) is opened, and the atmosphere gas separated from the atmosphere gas introduction path 15 to the atmosphere gas branch path 15a is sent to the insertion tube 18 of the sample container 11. The sample container is introduced into the reference container 12 through the same insertion tube 12b, and the atmospheric gas that has passed through the three-way switching valves 32 and 33 from the atmosphere gas introduction path 15 is introduced into the sample container 11 through the insertion tube 18. The operation of filling the atmosphere gas 11 and the reference container 12 in a predetermined high pressure state, closing the atmosphere gas introduction valve 35, and opening the purge exhaust valve 36 of the purge exhaust path 22a were provided on the upper part of the reference container 12. Atmospheric gas in the reference container 12 is discharged from the exhaust pipe 12c through the purge exhaust path 22a until it reaches the vicinity of atmospheric pressure, and the three-way switching valve 37 and the three-way switching valve 34 are discharged from the fluid lead-out path 22 connected to the upper part of the sample container 11. , The operation of discharging the atmospheric gas in the sample container 11 through the purge exhaust path 22a and the purge exhaust valve 36 until the atmospheric pressure is near, that is, the operation of filling the atmospheric gas in both containers 11 and 12 at high pressure and the operation of exhausting. The batch purge is repeated a predetermined number of times, for example, about 10 times.

After the batch purge is completed, the purge exhaust valve 36 is closed, and the heating means 14 is operated in a closed state in which the atmosphere gas adjusted to a predetermined pressure is filled in both the containers 11 and 12, and the sample is subjected to the predetermined conditions as in the conventional case. For example, the thermophysical property data of the sample is collected in the process of heating under the conditions of 0.5 ° C. per minute, 1 ° C. per minute, and 2 ° C. per minute, and heating to a predetermined temperature, for example, 500 to 600 ° C.

After collecting the data, when the heating by the heating means 14 is stopped and the sample container 11 drops to room temperature, the purge exhaust valve 36 is opened to return the inside of both containers 11 and 12 to atmospheric pressure, and then the purge exhaust valve 36 is closed. Next, the cleaning valve 38 is opened, the three-way switching valve 32 is switched to the straight line side, the three-way switching valve 33 and the three-way switching valve 37 are switched in the direction of the branched bypass path 24, and the cleaning fluid lead-out valve 39 is also opened. do.

Further, a cleaning liquid, for example, a 0.5% hydrofluoric acid aqueous solution is put in the cleaning liquid container 19, and a rinse liquid, for example, pure water is put in the rinse liquid container 20, and then the rinse liquid introduction valve 40 is opened and sent. The rinse liquid is introduced into the liquid feed pump 21a by using the position head of the rinse liquid in the rinse liquid container 20 arranged above the liquid pump 21a. At this time, by opening the pump exhaust valve 21b, the gas remaining in the liquid feed pump 21a and the peripheral piping is removed.

Then, the liquid feed pump 21a is started, the cleaning fluid lead-out valve 41 and the bypass valve 42 of the rinse liquid discharge path 25 branched from the fluid lead-out path 22 are opened, and the rinse liquid sent out from the liquid feed pump 21a is flowed to the system. The inside is washed with a rinse liquid (pure water), and a preliminary rinse operation is performed to discharge the inside from the rinse liquid discharge path 25 through the bypass path 25a. At this time, the flow rate of the rinse liquid can be adjusted by the pump bypass valve 21c, and the pressure can be confirmed by the pressure gauge 21d. After cleaning the inside of the system for a predetermined time, the bypass valve 42 is closed, the introduction valve 26a and the lead-out valve 26b of the conductivity measurement path 26 are opened, and the rinse liquid flowing in the system is sent to the sensor cell 23a of the conductivity meter 23. Introduce. When the indicated value of the conductivity meter 23 becomes stable, after recording this indicated value as a reference indicated value, the liquid feed pump 21a is stopped and all the valves are closed.

Next, the sample container 11 is washed with a washing liquid (hydrofluoric acid aqueous solution). First, the three-way switching valve 33 and the three-way switching valve 37 are switched from the direction of the bypass path 24 to the direction of the sample container 11, the cleaning liquid introduction valve 43 of the cleaning liquid container 19 is opened, and the inside of the cleaning liquid container 19 arranged above the liquid feed pump 21a. The cleaning liquid is introduced into the liquid feed pump 21a by using the position head of the cleaning liquid.

The cleaning valve 38, the cleaning fluid lead-out valve 39, the cleaning fluid lead-out valve 41, and the bypass valve 42 are opened, and the liquid feed pump 21a is started to circulate the cleaning liquid in the sample container 11. Since the rinse liquid remains in the system at the initial stage of introducing the cleaning liquid, the fluid in the system is discharged from the rinse liquid discharge path 25 through the bypass path 25a until a predetermined time elapses until the rinse liquid is sufficiently discharged. ..

After a lapse of a predetermined time, the cleaning fluid lead-out valve 41 is closed, the circulation valve 44 is opened, and the cleaning liquid led out from the sample container 11 to the fluid lead-out path 22 is circulated to the cleaning liquid container 19 through the circulation path 27 for reuse. After sufficiently cleaning the inside of the sample container 11 by a cleaning operation in which the cleaning liquid is circulated, the cleaning liquid introduction valve 43 is closed and the cleaning liquid is discharged from the system to perform a rinsing operation to clean the inside of the system.

In the rinsing operation, the rinsing liquid introduction valve 40, the cleaning fluid lead-out valve 41, and the bypass valve 42 are opened, and the rinsing liquid in the rinsing liquid container 20 is introduced into the system by the liquid feed pump 21a in the same manner as the preliminary rinsing operation described above. As a result, the cleaning liquid is discharged from the system and the sample container 11. After the lapse of a predetermined time, the bypass valve 42 is closed, the introduction valve 26a and the lead-out valve 26b are opened, and the rinse drainage discharged from the sample container 11 is introduced into the sensor cell 23a of the conductivity meter 23. Then, when the indicated value of the conductivity meter 23 reaches the recorded reference indicated value, the liquid feed pump 21a is stopped to end the rinsing operation.

After that, the introduction valve 26a and the lead-out valve 26b are closed, the bypass valve 42 is opened, and the purge gas is introduced into the system from the purge gas cylinder 28 via the pressure regulator 28a at a predetermined pressure, for example, 0.1 MPa. The gas is purged to discharge the rinse liquid remaining in the system, and the heating means 14 is operated to start the baking operation for heating the sample container 11. The temperature rising rate in the baking operation may be 1 to 2 ° C. per minute for 35 to 50 minutes, and the purge gas can be released by opening the sample charging valve 31 as needed. After the baking operation is completed, a series of cleaning treatments are completed by leaving the sample to room temperature and cooling it. The operation of collecting thermophysical property data can be started.

The sample container 11 can be formed of any material into any shape, but usually, it is preferably formed of stainless steel, for example, SUS316L, for example, the outer diameter is 17 mm, the inner diameter is 10 mm, and the bottom is hemispherical. It is preferable to have a so-called test tube shape. For the insertion tube 18 to be inserted into the sample container 11, for example, a stainless steel tube having an outer diameter of 3.18 mm and a wall thickness of 0.7 mm can be used, and the tip is inserted to a position about 5 mm away from the bottom surface. This makes it possible to reliably perform the cleaning process inside the sample container 11. The reference container 12 should be formed in the same shape as the sample container 11 in order to match the thermal characteristics. The reference container 12 can be used in an empty state in which nothing is put, but a suitable standard sample may be stored.

As the cleaning liquid, an appropriate cleaning liquid can be used depending on the material of the sample container 11, the type of sample, the type of reaction product or decomposition product at the time of collecting thermophysical characteristic data, but a hydrofluoric acid aqueous solution having strong cleaning power. It is preferable to use. The concentration of hydrofluoric acid in the aqueous hydrofluoric acid solution can be arbitrarily set, but usually, it is preferably in the range of 0.1 to 1.0% by mass, and in particular, by setting it to 0.5% by mass, the sample. Even if a material such as metal such as the container 11 is exposed to the cleaning liquid, damage can be reduced and the cleaning time can be shortened. The flow rate of the cleaning liquid is preferably about 300 cc per minute, and the flow rate in the sample container 11 is preferably set to less than 0.63 m / s. In particular, the cleaning effect is achieved by setting the flow rate to about 0.07 m / s. Can be fully demonstrated.

For example, after collecting the thermophysical property data of tetraethoxysilane (TEOS), silicon compound particles having a diameter of about 10 μm remain in the sample container 11, but as described above, fluoride having a concentration of about 0.5% by mass remains. The sample container 11 can be sufficiently removed by using a hydrofluoric acid aqueous solution, and the sample container 11 can be repeatedly washed to a usable state by rinsing with pure water and baking with nitrogen gas.

As the rinsing liquid, a cleaning liquid remaining in the system can be discharged, and a liquid that does not leave impurities in the system can be arbitrarily selected, but usually pure water may be used. Further, as the purge gas, a fluid that can discharge the rinsing liquid remaining in the system and does not adversely affect the sample container 11 or the like during baking can be arbitrarily selected, but usually high-purity nitrogen gas may be used. ..

As for the atmospheric gas, oxygen, fluorine, nitrogen, chlorine, NF ₃ , etc. may be selected as necessary for the purpose of measuring the thermal characteristics, as in the case of a normal differential scanning calorimeter, and two or more types may be mixed and used. You can also do it. In particular, when fluorine, chlorine, or NF ₃ is used as the atmosphere gas, a sample container having corrosion resistance is required, so that the cost for collecting thermophysical characteristic data is high. However, according to the present invention, the sample container is used. Since it can be used repeatedly, it is extremely effective in reducing costs. The pressure may be atmospheric pressure or higher and 29 MPa or lower.

11 ... sample container, 11a ... temperature measuring means, 12 ... reference container, 12a ... temperature measuring means, 12b ... insertion tube, 12c ... exhaust pipe, 13 ... furnace body, 14 ... heating means, 15 ... atmosphere gas introduction path, 15a ... Atmospheric gas branch path, 16 ... Purge gas introduction path, 17 ... Sample injection path, 18 ... Insert tube, 19 ... Cleaning liquid container, 20 ... Rinse solution container, 21 ... Cleaning fluid introduction path, 21a ... Liquid transfer pump, 21b ... Pump Exhaust valve, 21c ... Pump bypass valve, 21d ... Pressure gauge, 22 ... Fluid lead-out path, 22a ... Purge exhaust path, 23 ... Conductivity meter, 23a ... Sensor cell, 24 ... Bypass path, 25 ... Rinse solution discharge path, 25a ... Bypass path, 26 ... Conductivity measurement path, 26a ... Introduction valve, 26b ... Derivation valve, 27 ... Circulation path, 28 ... Purge gas cylinder, 28a ... Pressure regulator, 31 ... Sample input valve, 32 ... Three-way switching valve, 33 ... Three-way switching valve, 34 ... Three-way switching valve, 35 ... Atmospheric gas introduction valve, 36 ... Purge exhaust valve, 37 ... Three-way switching valve, 38 ... Cleaning valve, 39 ... Cleaning fluid lead-out valve, 40 ... Rinse liquid introduction valve, 41 ... Cleaning fluid lead-out valve, 42 ... Bypass valve, 43 ... Cleaning liquid introduction valve, 44 ... Circulation valve

Claims (7)

A furnace body that stores a sample container that stores a sample container and a reference container that stores a standard sample, a heating means that heats the sample container and the reference container, and an atmosphere gas that introduces an atmosphere gas for measurement into the sample container and the reference container. In a differential scanning calorimeter equipped with an introduction path and a temperature measuring means for measuring the temperature of the standard sample and the measurement sample, the purge gas introduction path for flowing the purge gas through the sample container and the measurement sample are charged into the sample container. The sample charging path, the insertion tube inserted inside the sample container, the cleaning liquid container storing the cleaning liquid, the rinsing liquid container storing the rinsing liquid, and the cleaning liquid or the rinsing liquid are sent toward the insertion tube. Conductivity for measuring the conductivity of the cleaning fluid introduction path having a pump, the fluid derivation path for deriving the fluid from the sample container, and the rinse drainage derivated from the fluid derivation path during the rinsing operation using the rinsing solution. A differential scanning calorimeter characterized by being equipped with a meter. The differential scanning calorimeter according to claim 1, further comprising a cleaning liquid return pipe that returns the cleaning waste liquid led out to the fluid lead-out path to the cleaning liquid container during a cleaning operation using the cleaning liquid. The differential scanning calorimetry according to claim 1 or 2, wherein the cleaning liquid is an aqueous hydrofluoric acid solution. The differential scanning calorimeter according to claim 3, wherein the hydrofluoric acid aqueous solution contains 0.1 to 1.0% by mass of hydrofluoric acid. The differential scanning calorimeter according to any one of claims 1 to 4, wherein the rinsing liquid is pure water. The differential scanning calorimeter according to any one of claims 1 to 5, wherein the flow rate of the cleaning liquid in the sample container is less than 0.63 m / sec. The differential scanning calorimeter according to any one of claims 1 to 5, wherein the flow velocity of the cleaning liquid in the sample container is 0.06 to 0.15 m / sec.

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