JPH08136483A - Thermal conductivity measuring apparatus - Google Patents

Abstract

PURPOSE: To evaluate the thermal conductivity of resin at high precision in the conditions of optional pressure and uniform density by heating a barrel and applying a prescribed pressure on an object to be measured. CONSTITUTION: The inside of a barrel storage part 1a is filled with an object 2 to be measured, which is resin, and the barrel 1 is heated by a heating plate 3. Consequently, while air being prevented from being mixed with the object 2 to be measured for uniform measurement, the object 2 to be measured is heated to at least thermal deformation temperature and melted. At that time, prescribed pressure is so applied to the object 2 to be measured by a load cell 8 and a piston 7 as not to cause density change due to the thermal expansion. After that, cooling water is made to circulate in the probe 4 to cool the probe 4 and forcedly cool the object 2 to be measured. At the same time, an electric power source for the heating plate 3 is turned off to cool the barrel 1 and limit the temperature rise of the object 2 to be measured at the most to near normal temperature and then the thermal conductivity of the object 2 to be measured is strated. Next, voltage is to a heater 5 to raise the temperature of the object 2 to be measured and the temperature rise is measured by a thermocouple 6 to measure the thermal conductivity. As a result, thermal conductivity of resin can be measured highly precisely in the condition of uniform density.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal conductivity measuring device, and more particularly, it can be applied to a thermal conductivity measuring technique considering temperature and pressure dependency, and in particular, under an arbitrary pressure,
Further, the present invention relates to a thermal conductivity measuring device capable of accurately evaluating the thermal conductivity of a resin under the condition of a constant density and accurately evaluating a change in thermal conductivity depending on temperature and pressure.

[0002]

2. Description of the Related Art Conventionally, the thermal conductivity of resin or powder containing resin (for example, toner) is measured by a room temperature method.
The object to be measured is solidified by heat or pressure and measured as a block, or when the measurement is carried out in a high temperature range, the measurement is carried out by gradually applying heat from the powder. In these methods for measuring thermal conductivity by the room temperature method or the high temperature region measuring method, the thermal conductivity is always measured without forcibly applying pressure to the object to be measured. In high temperature measurement, the thermal conductivity is evaluated by ignoring the volume change due to thermal expansion.

A conventional thermal conductivity measuring device will be described with reference to the drawings. FIG. 4 is a sectional view showing the structure of a conventional thermal conductivity measuring device. In FIG. 4, reference numeral 101 is a barrel for housing a measured object 102 made of resin or powder containing resin in a barrel housing portion 101a, and 103 is a heating plate provided around the barrel 101 for heating the barrel 101.

Reference numeral 104 is a probe provided on the barrel bottom plate 101b in the barrel housing 101a in a direction perpendicular to the barrel bottom plate 101b, and 105 is a probe 104.
It is a rod-shaped heater that heats the probe 104 provided in the same direction as the probe 104 and linearly. 1
Reference numeral 06 is a thermocouple that passes through the barrel 101 and is provided up to the side of the barrel storage portion 101a to measure the temperature of the object 102 to be measured in the barrel storage portion 101a, and 101c is a barrel lid.

Conventionally, the object to be measured 102 is placed on the barrel 101.
Barrel cover 101c
After the barrel housing portion 101a is closed with, the object to be measured 102 is heated to a temperature not lower than the thermal deformation temperature through the barrel 101 by the heating plate 103 provided around the barrel 101. After that, heating plate 1
Turn off the power of 03 and let the object to be measured 10 cool by itself.
After cooling 2 to room temperature, measurement of the thermal conductivity of the DUT 102 is started.

To measure the thermal conductivity, an applied voltage is applied to the heater 105 provided in the probe 104 to raise the temperature of the object 102 to be measured in the barrel housing 101a, and the barrel 101 is heated.
The temperature rise of the object 102 to be measured is measured by the thermocouple 106 provided at the position. The thermal conductivity is 10
It is calculated from the measured temperature of 2, the distance between the thermocouple 106 and the probe 104, and the applied voltage and application time of the heater 105.

[0007]

However, in the above-mentioned conventional thermal conductivity measuring device, the thermal conductivity is measured under atmospheric pressure without always forcibly applying pressure to the object 102 to be measured, Especially when the measurement is performed in the high temperature range, the thermal conductivity is evaluated by ignoring the volume change due to the thermal expansion of the resin.

Therefore, there is a problem that it is difficult to evaluate the thermal conductivity under the condition that the density is constant, and it is difficult to accurately evaluate the change of the thermal conductivity depending on the temperature and the pressure. Therefore, for example, when the resin is pressure-molded, it was not possible to obtain the pressure-molding condition by simulating the pressure-molding condition in consideration of the thermal conductivity. Therefore, the present invention can accurately evaluate the thermal conductivity of the resin under an arbitrary pressure and under the condition that the density is constant, and accurately evaluate the thermal conductivity change depending on the temperature and the pressure. It is an object of the present invention to provide a thermal conductivity measuring device that can be used.

[0009]

According to the first aspect of the present invention,
In a thermal conductivity measuring device for measuring the thermal conductivity of an object to be measured, which comprises a resin or a powder mixture containing the resin, a barrel having a barrel housing part for accommodating the object to be measured, and the barrel provided around the barrel. A heating means for heating the probe, a probe provided on the bottom plate of the barrel in the barrel housing, a second heating means for heating the probe provided in the probe, and a heating means provided in the barrel. It has a temperature measuring means for measuring the temperature of the object to be measured and a pressing means for applying a predetermined pressure to the object to be measured filled in the barrel housing portion.

According to a second aspect of the present invention, in the above-mentioned first aspect of the invention, the temperature measuring means comprises at least two or more temperature sensors. According to a third aspect of the present invention, in the first and second aspects of the present invention, the second heating means includes a heater arranged circumferentially in the probe.

A fourth aspect of the present invention is characterized in that, in the first to third aspects of the present invention, the probe is provided with a groove for passing a cooling medium. The invention according to claim 5 is the invention according to any one of claims 1 to 4, characterized by further comprising temperature rise limiting means for limiting the temperature rise of the object to be measured based on the temperature measured by the temperature measuring means. To do.

[0012]

According to the first aspect of the present invention, the barrel having the barrel housing portion for housing the object to be measured, the first heating means for heating the barrel provided around the barrel, and the bottom plate of the barrel in the barrel housing portion are provided. The probe provided, the second heating means for heating the probe provided in the probe, the temperature measuring means for measuring the temperature of the object to be measured provided in the barrel, and the object to be measured filled in the barrel housing portion are predetermined. And a pressing means for applying pressure.

For this reason, when the thermal conductivity is measured particularly in a high temperature range, an arbitrary pressure is appropriately applied to the object to be measured filled in the barrel housing portion by the pressing means to suppress the volume change due to the thermal expansion of the resin. The thermal conductivity of the resin can be accurately evaluated under the condition that the density is constant. Therefore,
It is possible to accurately evaluate changes in thermal conductivity depending on temperature and pressure. For example, when the resin is pressure-molded, it can be obtained by simulating the pressure-molding conditions in consideration of the thermal conductivity in consideration of not only the temperature but also the pressure.

According to the second aspect of the invention, the temperature measuring means is composed of at least two temperature sensors. Therefore, by arranging and arranging a plurality of temperature sensors appropriately, even if the temperature distribution occurs in the resin of the measured object filled in the barrel housing portion, it is possible to average the measured temperatures at a plurality of points. Therefore, the measurement error can be made smaller and the thermal conductivity measurement can be performed with higher reliability than in the case of measuring with one conventional temperature sensor.

According to the third aspect of the invention, the second heating means is constituted by a heater arranged circumferentially in the probe. Therefore, by arranging the heater on the circumference of the probe, the probe can be heated uniformly and faster than the case of arranging the conventional rod-shaped heater. Therefore, the object to be measured can be efficiently heated through this probe.

Next, when measuring the thermal conductivity of a powder measurement object, the air layer between the particles acts as a heat insulating material in the normal temperature to low temperature range, and the accurate thermal conductivity of the measurement object is measured. It will be a lower value. In order to avoid this, once melting and heating to a high temperature region, cooling is performed. Conventionally, in order to prepare this sample, the heating means is turned off and the sample is naturally cooled. Therefore, a long cooling time is required and the measurement efficiency is poor.

Therefore, in the invention according to the fourth aspect, the probe is configured to have a groove through which the cooling medium passes.
Therefore, by forcing the cooling medium to flow through the groove provided in the probe to cool the probe, it is possible to cool the probe faster than in the case where natural cooling is performed conventionally. Therefore, by heating the probe quickly, the object to be measured in contact with the probe can be cooled quickly, so that the sample preparation time can be shortened and efficient sample preparation can be performed.

According to the fifth aspect of the present invention, the temperature rise limiting means limits the temperature rise of the object to be measured based on the temperature measured by the temperature measuring means. Therefore, by limiting the application time of the first heating means for heating the barrel and limiting the temperature rise of the object to be measured, even if the heater of the probe generated by the heat applied to the barrel is applied, the resin temperature remains It is possible to prevent the adverse effect that it is difficult to climb up.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a sectional view showing the structure of a thermal conductivity measuring apparatus according to an embodiment of the present invention, and FIG. 2 is a sectional view showing the structure of the probe shown in FIG. In FIGS. 1 and 2, 1 is a barrel having a barrel housing portion 1a for housing a DUT 2 made of a semiconductor mixture such as a resin such as polycarbonate or PBS (polybutadiene styrene) or a toner containing the resin, and 3 is a barrel. 1 is a heating plate that heats a barrel 1 provided around the same. Reference numeral 4 denotes a probe provided on the barrel bottom plate 1b in the barrel housing 1a in a direction perpendicular to the barrel bottom plate 1b, and 5 heats the probe 4 provided on the circumference of the probe 4. It is a heater.

Reference numeral 6 passes through the inside of the barrel 1 and a barrel storage portion 1a.
Object to be measured 2 in barrel storage 1a provided up to the side
Is a thermocouple for measuring the temperature of the thermocouple, and three thermocouples 6 are provided at each of the upper portion, the middle portion, and the lower portion of the barrel housing portion 1a. Reference numerals 7 and 8 are pistons and load cells for applying an arbitrary pressure to the object to be measured 2 in the barrel housing portion 1a, and 9 is a groove provided in the probe 4 for flowing a cooling medium.

Next, a thermal conductivity measuring method in the thermal conductivity measuring apparatus of this embodiment will be described. In this embodiment,
First, the device under test 2 filled in the barrel storage part 1a is heated by filling the device under test 2 into the barrel storage part 1a of the barrel 1 and heating the barrel 1 with the heating plate 3 provided around the barrel 1. Melts by heating above the deformation temperature. Here, what is being melted by heating the DUT 2 above the thermal deformation temperature is
When the object to be measured 2 has a thermal deformation temperature or higher, an air layer is mixed into the object to be measured 2 and it becomes difficult to perform uniform measurement of the object to be measured 2. Therefore, the object to be measured 2 is melted and the air layer is mixed. This is because it is difficult to perform and uniform measurement is performed.

At this time, in order to suppress the volume change of the DUT 2 due to the thermal expansion due to the temperature rise and the density change, the barrel cell 1 and the piston 7 are used to prevent the change in density.
A predetermined pressure is applied to the DUT 2 in a. After that, a cooling medium such as water is circulated in the groove 9 for passing the cooling medium provided inside the probe 4 to forcibly cool the probe 4, and the forcedly cooled probe 4 is passed through the inside of the barrel housing portion 1a. The DUT 2 is forcibly cooled.

Next, simultaneously with the forced cooling, the object to be measured 2
In order to limit the temperature rise of the
Alternatively, the temperature set by the thermocouple 6 provided in the barrel 1 is set to around room temperature, and the barrel 1 is cooled by the controller. Then, after the DUT 2 is cooled to room temperature, the thermal conductivity measurement of the DUT 2 is started. Next, an applied voltage is applied to the heater 5 provided in the probe 4 to raise the temperature of the DUT 2 in the barrel housing portion 1a, and the thermocouple 6 provided in the barrel 1 raises the temperature of the DUT 2. The thermal conductivity is measured by measuring. Then, the thermal conductivity is calculated from the measured temperature of the DUT 2, the distance between the thermocouple 6 and the probe 4, the applied voltage of the heater 5 and the applied time thereof.

In this embodiment, the applied voltage and the applied time to the heater 5 are preferably changed according to the thermal conductivity of the DUT 2. As shown in FIG. 3, the one having good thermal conductivity rises in temperature on the straight line of the case 1, while the one having poor thermal conductivity draws a curve like the case 2. Since the thermal conductivity is calculated from this slope, there is no problem in case 1, but in case 2 the slope is different between the region where the application time is short and the region where the application time is long.
In the present embodiment, the region where the application time is short is considered to be the thermal conductivity of the DUT 2, and the long region is considered to be the influence of the barrel 1.
Therefore, in the case of Case 2, the condition is that measurement is performed in a short application time.

Thus, in this embodiment (claim 1),
A barrel 1 having a barrel housing portion 1a for housing the DUT 2, a heating plate 3 for heating the barrel 1 provided around the barrel 1, a probe 4 provided on a barrel bottom plate 1b in the barrel housing portion 1a, A heater 5 provided in the probe 4 for heating the probe 4, a thermocouple 6 provided in the barrel 1 for measuring the temperature of the object 2 to be measured, and the object 2 to be filled in the barrel housing 1a are provided with a predetermined size. It is configured to have a piston 7 for applying pressure and a load cell 8.

Therefore, particularly when the thermal conductivity is measured in a high temperature range, an arbitrary pressure is appropriately applied to the object to be measured 2 filled in the barrel housing 1a by the piston 7 and the load cell 8 to keep it constant (piston 7). By keeping the position constant), the volume change due to the thermal expansion of the resin of the DUT 2 can be suppressed, and the thermal conductivity of the DUT 2 can be accurately evaluated under the condition that the density is constant. . Therefore, the change in thermal conductivity depending on temperature and pressure can be accurately evaluated. For example, when the resin is pressure-molded, it can be obtained by simulating the pressure-molding conditions in consideration of the thermal conductivity in consideration of not only the temperature but also the pressure.

In this embodiment (claim 2), the temperature of the object to be measured 2 is measured by three thermocouples 6. Therefore, by appropriately disposing the three thermocouples 3 and arranging them, even if the temperature distribution is generated in the DUT 2, it is possible to average the temperatures at the three measured points. Compared with the case of measuring with one conventional thermocouple,
It is possible to reduce the measurement error and perform highly reliable thermal conductivity measurement.

In this embodiment (claim 3), the heater 5 in the probe 4 is arranged on the circumference of the probe 4. Therefore, by arranging the heater 5 on the circumference in the probe 4, it is possible to heat the probe 5 uniformly and faster than when the conventional rod-shaped heater is arranged. Therefore, the DUT 2 can be efficiently heated via the probe 5.

In this embodiment (claim 4), a groove 9 for passing a cooling medium is provided in the probe 5.
For this reason, by forcing the cooling medium to flow through the groove 9 provided in the probe 5 to cool the probe 5, the probe 5 can be cooled faster than in the case of performing conventional natural cooling. Therefore, since the DUT 2 can be cooled quickly through the probe 5, the sample preparation time can be shortened and the sample preparation can be performed efficiently.

In this embodiment (Claim 5), the heating plate 3 is turned off based on the temperature measured by the thermocouple 6,
The temperature rise of the DUT 2 is limited by controlling the power supply of the heating plate 3 to turn ON / OFF so as to control the set temperature of the barrel 1. Therefore, by limiting the application time of the heating plate 3 for heating the barrel 1 to limit the temperature rise of the DUT 2, the heater 5 of the probe 4 caused by the heat applied to the barrel 1
It is possible to prevent the adverse effect that the resin temperature is hard to rise even if is applied.

[0031]

According to the present invention, the thermal conductivity of a resin can be evaluated under an arbitrary pressure and under a constant density condition, and the thermal conductivity change depending on temperature and pressure can be accurately measured. The effect is that it can be evaluated well.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing the structure of a thermal conductivity measuring apparatus according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing the structure of the probe shown in FIG.

FIG. 3 is a diagram showing measured temperature results of a thermocouple with respect to a voltage application time to a heater when a measured object has good thermal conductivity and when the measured object has poor thermal conductivity.

FIG. 4 is a cross-sectional view showing the structure of a conventional thermal conductivity measuring device.

[Explanation of reference symbols] 1 barrel 1a barrel housing 1b barrel bottom plate 2 DUT 3 heating plate 4 probe 5 heater 6 thermocouple 7 piston 8 load cell 9 groove

Claims (5)

[Claims] 1. A thermal conductivity measuring device for measuring the thermal conductivity of an object to be measured, which comprises a resin or a powder mixture containing the resin, and a barrel having a barrel accommodating portion for accommodating the object to be measured, and the periphery of the barrel. For heating the barrel provided in the first
Heating means, a probe provided on the bottom plate of the barrel in the barrel housing, second heating means for heating the probe provided in the probe, and the object to be measured provided in the barrel. A thermal conductivity measuring device comprising: a temperature measuring means for measuring a temperature; and a pressing means for applying a predetermined pressure to the object to be measured filled in the barrel housing portion. 2. The thermal conductivity measuring device according to claim 1, wherein the temperature measuring means comprises at least two temperature sensors. 3. The thermal conductivity measuring device according to claim 1, wherein the second heating means comprises a heater arranged on the circumference of the probe. 4. The thermal conductivity measuring device according to claim 1, wherein the probe is provided with a groove through which a cooling medium passes. 5. The thermal conductivity measuring device according to claim 1, further comprising a temperature rise limiting means for limiting the temperature rise of the object to be measured based on the temperature measured by the temperature measuring means.