Sample container and thermal analysis device

Abstract

To provide a sample container and thermal analysis device, which enable stable observation of a measurement sample regardless of the surface condition of the sample container during thermal analysis.SOLUTION: A sample container 2 for use with a thermal analysis device 1 designed to measure thermal behavior associated with temperature changes of a measurement sample S due to heating or cooling and to observe the measurement sample is provided, the sample container comprising a cylindrical main body 21 with a bottom and an open top, and a mounting plate 23 placed on a bottom surface 21b inside the main body and designed to mount a measurement sample thereon, where a surface 23a of the mounting plate facing the measurement sample has an average roughness Ra1 that is less than an average roughness Ra2 of the bottom surface.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a sample container used in a thermal analysis apparatus for heating a (measurement) sample and measuring a physical change including thermogravimetric or calorimetric measurement of the measurement sample accompanying a temperature change, and a thermal analysis apparatus using the same.

Background Art

[0002] Conventionally, as a method for evaluating the temperature characteristics of a sample, a method called thermal analysis in which the sample is heated and the physical change of the sample accompanying the temperature change is measured has been performed. Thermal analysis is defined in JIS K 0129:2005 "General Rules for Thermal Analysis", and all methods for measuring the physical properties of a measurement object (sample) when the temperature of the measurement object (sample) is programmed are regarded as thermal analysis. Generally used thermal analysis includes (1) differential thermal analysis (DTA) for detecting temperature (temperature difference), (2) differential scanning calorimetry (DSC) for detecting heat flow difference, (3) thermogravimetric measurement (TG) for detecting mass (weight change), (4) thermomechanical analysis (TMA) for detecting mechanical properties, and (5) dynamic viscoelasticity measurement (DMA). In addition, there is also a thermogravimetric / differential thermal simultaneous measurement apparatus (TG / DTA or TG / DSC) that simultaneously measures thermogravimetry and differential heat (for example, see Patent Document 1).

[0003] In addition, in recent years, there has been a desire to observe the state of a sample during thermal analysis. A thermal analysis apparatus is known in which an opening is provided in a heating furnace for heating the sample, and the sample can be observed through this opening. In such an observation, a bottomed cylindrical sample container with an open upper part as described in Patent Document 2 is used.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, if polishing marks from container molding or the rough surface of the container material remain on the upper surface side of the bottom surface of the sample container, the roughness of the bottom surface may affect the reflected light during sample observation, making it difficult to observe the sample. In particular, when the sample is (semi)transparent, there has been a problem that the surface on the upper surface side of the bottom surface of the sample container located below the sample affects sample observation. The present invention has been made to solve the above problems, and an object thereof is to provide a sample container and a thermal analysis apparatus that can stably observe a measurement sample regardless of the surface state of the sample container during thermal analysis.

Means for Solving the Problems

[0006] In order to achieve the above object, a sample container of a thermal analysis apparatus is a sample container used in a thermal analysis apparatus that measures the thermal behavior accompanying a temperature change due to heating or cooling of a measurement sample and observes the measurement sample, and includes a main body portion having a bottomed cylindrical shape with an open upper portion, and a placement plate placed on the bottom surface inside the main body portion for placing the measurement sample on itself, and the average roughness Ra1 of the surface of the placement plate facing the measurement sample is smaller than the average roughness Ra2 of the bottom surface.

[0007] According to this sample container of the thermal analysis apparatus, when a placement plate having a roughness smaller than that of the bottom surface is placed on the bottom surface of the main body portion, the influence of the roughness of the bottom surface is eliminated, and the measurement sample can be stably observed regardless of the surface state of the bottom surface of the main body portion.

[0008] In the sample container of the thermal analysis apparatus of the present invention, the measurement sample may be transparent or semi-transparent. When the measurement sample is transparent or semi-transparent, the surface on the upper surface side of the bottom surface of the sample container located below the measurement sample does not affect sample observation, and the measurement sample can be observed more stably.

[0009] In the sample container of the thermal analysis apparatus of the present invention, Ra1 may be 0.2 μm or less. According to the sample container of this thermal analyzer, the surface of the mounting plate can be reliably smoothed, so the influence due to the roughness of the mounting plate is suppressed, and the measurement sample can be observed more stably.

[0010] In the sample container of the thermal analyzer of the present invention, the thermal conductivity of the mounting plate at 25°C may be the same as that of the main body at 25°C within ±10%. According to the sample container of this thermal analyzer, when heating or cooling during measurement by the thermal analyzer, the degree of heat conduction between the mounting plate and the main body becomes the same, so the measurement sample can be observed more stably.

[0011] In the sample container of the thermal analyzer of the present invention, the mounting plate and the main body may be made of the same material. According to the sample container of this thermal analyzer, if the mounting plate and the main body are made of the same material, the thermal conductivities of both will match.

[0012] The thermal analyzer of the present invention includes the sample container of the thermal analyzer, a heating furnace that surrounds the periphery of the sample container and has an observation opening, and imaging means capable of observing the measurement sample through the observation opening. It is characterized by measuring the thermal behavior accompanying the temperature change of the measurement sample in the heating furnace.

[0013] The thermal analyzer of the present invention may be a differential thermal analyzer, a differential scanning calorimeter, or a thermogravimetric analyzer.

[0014] The thermal analyzer of the present invention further includes image processing means for generating predetermined color information from the image data of the measurement sample acquired by the imaging means, and the color information and the thermal behavior may be superimposed and displayed with respect to temperature.

Advantages of the Invention

[0015] According to the present invention, a sample container and a thermal analyzer capable of stably observing a measurement sample regardless of the surface state of the sample container during thermal analysis can be obtained.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0017] Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing the configuration of a thermal analyzer according to an embodiment of the present invention. The thermal analyzer 1 is a differential scanning calorimeter (DSC), and has the same configuration as a conventional differential scanning calorimeter except that a window 11W through which the inside can be observed is provided in the lid 11 of the heating furnace 10, so an overview will be described.

[0018] The thermal analyzer 1 includes a measurement sample container 2 for storing a measurement sample S, a reference substance container 3 for storing a reference substance R, a heating furnace 10, a thermal resistor 4 connected between the measurement sample container 2 and the reference substance container 3 and the heating furnace 10 to form a heat flow path therebetween, a measurement sample side thermocouple 7, a reference substance side thermocouple 8, a light source 31 such as an LED serving as illumination means for irradiating at least the measurement sample S with visible light, a CCD camera 32 serving as imaging means for imaging at least the measurement sample S, and a personal computer 50. A wound wire heater 12 is wound around the outer periphery of the heating furnace 10 to heat the heating furnace 10. Note that the outside of the heater 12 is covered with a cover (not shown). The CCD camera 32 is, for example, an area scan type, but may be a line scan type or the like, or other solid-state imaging devices such as a CMOS camera may be used.

[0019] The personal computer 50 includes a CPU (Central Processing Unit) 51, a storage unit 52 such as a hard disk, a display unit 53 such as a liquid crystal monitor, and a keyboard, a mouse, etc. (not shown).

[0020] The heating furnace 10 is formed in a cylindrical shape, and the cross-section along the axial direction is in an H shape. And, a substantially double-disk-shaped heat plate 5 is placed above an annular protrusion protruding radially inward from the center in the axial direction. Furthermore, on the upper surface of the heat plate 5, a measurement sample container 2 and a reference substance container 3 are respectively placed via two heating resistors 4, and the measurement sample container 2 and the reference substance container 3 are accommodated in the internal space surrounded by the heating furnace 10.

[0021] The measurement sample container 2 contains a measurement sample S, a pressing plate 22 is placed on the upper surface of the measurement sample S, and a mounting plate 23 is interposed between the bottom surface of the measurement sample container 2 and the measurement sample S (Fig. 2). Here, the pressing plate 22 is transparent or translucent and is made of a material that transmits visible light at a predetermined light transmittance. As the transparent (translucent) material, quartz glass, sapphire glass, or YAG (yttrium aluminum garnet) ceramics, Temperax, Neoceram (registered trademark), Vycor, Pyrex (registered trademark) can be preferably used. On the other hand, for the reference substance container 3 holding the reference substance R, in order to ensure that the measurement sample S and the reference substance R are heated under the same conditions in the heating furnace 10, it is desirable to place the same pressing plate as that of the measurement sample container on the reference substance R. Note that the pressing plate 22 is not an essential configuration in the present invention. Also, when using the pressing plate 22, it may be used at least on the measurement sample container 2 side. However, it is desirable to place the same pressing plate as that of the measurement sample container on the reference substance R in the reference substance container 3 as well.

[0022] The thermocouple 7 on the measurement sample side and the thermocouple 8 on the reference material side penetrate the heat resistor 4 and the heat plate 5, and the tips thereof are connected to the lower surfaces of the measurement sample container 2 and the reference material container 3 by brazing or the like. On the other hand, the other ends of the thermocouple 7 on the measurement sample side and the thermocouple 8 on the reference material side are drawn out below the heating furnace 10 and connected to an amplifier 14 forming a signal processing circuit. In this way, the thermocouple 7 on the measurement sample side and the thermocouple 8 on the reference material side form a so-called differential thermocouple, and can detect the temperature difference between the measurement sample S and the reference material R. This temperature difference is recorded as a heat flow difference signal. On the other hand, the temperature of the measurement sample is recorded from the thermocouple 7 on the measurement sample side.

[0023] Furthermore, the temperature of the heating furnace 10 is input to the CPU 51 via various control circuits, and the CPU 51 controls the energization of the heater 12 to control the heating furnace 10 to be heated or cooled at a constant speed.

[0024] Also, a lid 11 is detachably placed on the upper end opening of the heating furnace 10, blocking the inside of the heating furnace 10 from the outside air. Furthermore, a window 11W made of quartz glass is provided at a portion of the lid 11 that overlaps the measurement sample container 2 in the axial direction of the heating furnace 10, and a CCD camera 32 is arranged above the window 11W. Also, a light source 31 for illuminating the measurement sample S in the heating furnace 10 through the window 11W is arranged on a line different from the axis of the CCD camera 32 above the window 11W. Incident light (visible light) 31L is irradiated from the light source 31 to the measurement sample S, and the CCD camera 32 acquires the luminance and intensity of the reflected light 32L from the measurement sample S.

[0025] Filters 31F and 32F are arranged between the window 11W and the light source 31, and between the window 11W and the CCD camera 32, respectively, irradiating only light of a specific component to the window 11W and allowing only the reflected light of the specific component to be received by the CCD camera 32. However, the filters 31F and 32F are not essential. Also, in the case of coaxial epi-illumination (half mirror type), the optical axes of the light source 31 of the irradiation light and the camera 32 coincide.

[0026] Next, the measurement sample container 2 according to the embodiment of the present invention will be described by taking the measurement sample container 2 as an example. FIG. 2 is a perspective view showing the configuration of the measurement sample container 2, and FIG. 3 is a cross-sectional view along the axial direction L of the measurement sample container 2. The measurement sample container 2 includes a main body portion 21 having a bottomed cylindrical shape with an open upper portion, a pressing plate 22, a mounting plate 23, and a lid portion 24. The pressing plate 22, the mounting plate 23, and the lid portion 24 have substantially the same diameter as the inner diameter of the main body portion 21 or a slightly smaller diameter than the inner diameter, and have a substantially disc shape. The pressing plate 22 is transparent or translucent as described above, and presses the measurement sample S placed on the bottom surface of the main body portion 21 from above. The main body portion 21, the mounting plate 23, and the lid portion 24 are made of, for example, aluminum (alloy). Note that the pressing plate 22 and the lid portion 24 are not essential components of the present invention.

[0027] The mounting plate 23 is placed on the bottom surface 21b inside the main body portion 21 and is for placing the measurement sample S on itself. Here, the average roughness Ra1 of the surface (upper surface) 23a of the mounting plate 23 facing the measurement sample S is smaller than the average roughness Ra2 of the bottom surface 21b. The average roughness Ra1 and Ra2 can be the arithmetic average roughness defined in JIS - B0601:2013.

[0028] If polishing marks remain on the bottom surface 21b inside the main body portion 21 during the molding of the main body portion 21, or if the rough surface of the material of the main body portion 21 remains, especially when the measurement sample is (semi) transparent, the roughness of the bottom surface 21b will affect the reflected light during sample observation, making it difficult to observe the sample. Therefore, as shown in FIG. 3, when the mounting plate 23 with a roughness smaller than that of the bottom surface 21b is placed on the bottom surface 21b, the incident light 31L transmitted through the measurement sample S is reflected on the surface of the mounting plate 23 to become the reflected light 32L. Thus, the influence of the roughness of the bottom surface 21b is eliminated, and the measurement sample can be stably observed regardless of the surface state of the bottom surface 21b of the main body portion 21.

[0029] When Ra1 is 0.2 μm or less, the surface of the mounting plate 23 can be surely made smooth, so the influence due to the roughness of the mounting plate 23 can be suppressed, and the measurement sample can be observed more stably. When the coefficient of thermal expansion of the mounting plate 23 at 25°C is the same as that of the main body 21 at 25°C within ±10%, the degrees of thermal expansion of the mounting plate 23 and the main body 21 become equivalent during heating and cooling when measuring with the thermal analyzer. Thus, the measurement sample can be observed more stably. In particular, it is preferable that the mounting plate 23 and the main body 21 are made of the same material, as their coefficients of thermal expansion will then match.

[0030] In this example, the pressing plate 22 is placed on the upper surface of the measurement sample S and presses the measurement sample S from above. As a result, the pressing plate 22 holds the measurement sample S and suppresses deformation of the measurement sample S due to heating and cooling during measurement with the thermal analyzer, enabling more stable observation of the measurement sample.

[0031] Also, in this example, the lid portion 24 is placed on the upper surface of the pressing plate 22. One hole 24h for observing the measurement sample is opened at the center of the lid portion 24. Further, the (outer) peripheral edge 24e of the lid portion 24 rises vertically upward to form a flange.

[0032] Then, as shown in FIG. 4, with the measurement sample S disposed between the bottom surface of the main body 21 and the pressing plate 22, at least a part (in this example, over the entire circumference) of the opening edge portion 21e of the main body 21 and the outer peripheral edge (flange) 24e of the lid portion 24 are bent downward together to form a bent portion 26. By forming the bent portion 26, the lid portion 24 is pressed downward (toward the pressing plate 22). As a result, the pressing plate 22 presses the measurement sample S via the lid portion 24, making the holding of the measurement sample S even more sufficient and further suppressing deformation of the measurement sample S and the pressing plate 22. Note that in order to enable bending, the opening edge portion (side wall in this example) 21e of the main body 21 and the peripheral edge (flange) 24e of the lid portion 24 need to be substantially parallel, and it is necessary for the lid portion 24 to form a flange.

[0033] Note that the opening end 21e and the peripheral edge (flange) 24 may be joined by means such as winding used in can manufacturing or the like for the bent portion. Also, although it is preferable that the entire circumference of the open end 21e and the periphery (flange) 24e be bent, if the measurement sample S can be sufficiently held down, a part of the periphery (for example, four locations at equal intervals in the circumferential direction) may be used instead.

[0034] Next, according to the flowchart of FIG. 5, the operation of the sample container and the thermal analysis apparatus using the same will be described. First, visible light is irradiated onto the measurement sample S by the light source 31, and initial image data of the measurement sample S is acquired by the CPU 51 of the personal computer 50 using the CCD camera 32 (step S10).

[0035] Next, the image data is displayed on the display unit 53 of the personal computer 50, and the user sets the position information of the analysis region in the image of the measurement sample S on the display unit 53 using a mouse or a keyboard (not shown) or the like (step S12). Note that this position information may be a single point or a region having an area that traces the outer edge. Also, when a single point is specified, a circle or the like having a predetermined radius or a predetermined area centered on that point may be regarded as a virtual region.

[0036] While heating or cooling the measurement sample S by the heater 12 or a cooling means (not shown), a heat flow difference signal (DSC signal) is acquired at each time (step S14). The process of step S14 is the same as the process performed by a conventional differential scanning calorimetry (DSC) meter. Heating or cooling is performed on the measurement sample S itself, and its differential scanning calorimetry (DSC) is measured. Note that in the present invention, the DSC signal is acquired with respect to either the variable of time or temperature. In a general differential scanning calorimeter, the heating or cooling rate is constant, and time and temperature are correlated.

[0037] The CCD camera 32 acquires image data of the image of the measurement sample S at each time and outputs the image data to the CPU 51. (Step 16) When acquiring the image data in step S16, it is preferable to use the same variable as the variable (time in this embodiment) for acquiring the heat flux difference signal (DSC signal) in step S14, but different variables may also be used.

[0038] Next, the CPU 51 acquires the image data of the position information portion of the measurement sample S set in step S12 from the image data for each time in step S16 (step S18). This image data is stored in the storage unit 52. When the measurement sample S is an area having an area, a value obtained by averaging the luminance or intensity of each pixel of the image data within that area is adopted.

[0039] The image data of the measurement sample S acquired in step S18 and the heat flux difference signal (DSC signal) of the measurement sample S acquired in step S14 are superimposed and displayed on the display unit 53. (Step 20) Next, the user determines whether measurement is to be terminated. If it is necessary (YES), the measurement is terminated. If it is not necessary (NO), the process returns to step S14. (Step S22). Note that the determination of whether measurement is to be terminated in step S24 may be made by, for example, regarding the maximum temperature or minimum temperature at which the measurement sample S is heated or cooled in advance as the end temperature and considering the measurement to be terminated, and there is no particular limitation.

[0040] In the above embodiment, visible light from a light source is irradiated. However, electromagnetic waves other than visible light such as X-rays, infrared rays, and ultraviolet rays may be irradiated, and the reflected light may be detected by a detector other than a CCD camera such as an X-ray detector.

[0041] Further, an image of the measurement sample S may be acquired as a color change. As the color, in addition to the luminance of a specific wavelength, information obtained by quantifying the color may also be used. Examples of this quantified information include Lab (L*a*b*) values in the CIE (International Commission on Illumination) 1976 color space; RGB values representing colors by combinations of Red, Green, and Blue, which are called the "three primary colors of light"; CMYK values representing colors by combinations of three colors, Cyan, Magenta, and Yellow, which are called the "three primary colors of color", and Black; and the like, but are not limited thereto. For example, XYZ values in the CIE 1931 color space, L*u*v* values in the CIE 1976 color space, CIECAM02, etc. may also be mentioned.

[0042] The present invention is not limited to the above-described embodiments, and it goes without saying that the present invention extends to various modifications and equivalents included in the spirit and scope of the present invention. For example, the shapes of the sample container, the main body, the mounting plate, etc. are not limited to the examples described above. For example, the sample container is not limited to a cylinder, and may be a rectangular tube or an elliptical tube. Further, the thermal analysis apparatus of the present invention, in addition to the above-described thermogravimetric / differential thermal measurement (TG / DTA) apparatus defined in JIS K 0129:2005 "General Rules for Thermal Analysis", measures the physical properties of a sample when the temperature of the measurement object (sample) is program-controlled, and can be applied to a thermal analysis apparatus equipped with differential scanning calorimetry (DSC) for detecting a heat flow difference, but can also be applied to a differential thermal analysis (DTA) meter and a thermogravimetric measurement (TG) meter.

Explanation of Reference Numerals

[0043] 1 Thermal analysis apparatus 2 (Measurement) Sample container 10 Heating furnace 11W Observation opening (window) 21 Main body 21b Bottom surface inside the main body 23 Mounting plate 23a Surface of the mounting plate facing the measurement sample 31 Light source 32 Imaging means (CCD camera) 51 CPU (Control unit) 53 display unit S (measurement) sample

Claims

1. A sample container used in a thermal analyzer that measures the thermal behavior accompanying temperature changes due to heating or cooling of a measurement sample and observes the measurement sample, comprising: a main body portion having a bottomed cylindrical shape with an open top; a placement plate placed on the bottom surface inside the main body portion for placing the measurement sample thereon; and comprising; The sample container of a thermal analyzer, wherein the average roughness Ra1 of the surface of the placement plate facing the measurement sample is smaller than the average roughness Ra2 of the bottom surface.

2. The sample container of the thermal analyzer according to claim 1, wherein the measurement sample is transparent or translucent.

3. The sample container of the thermal analyzer according to claim 1, wherein Ra1 is the arithmetic mean roughness defined in JIS-B0601:2013, and Ra1 is 0.2 μm or less.

4. The sample container of the thermal analyzer according to claim 1 or 2, wherein the thermal conductivity of the placement plate at 25°C is the same as the thermal conductivity of the main body portion at 25°C within ±10%.

5. The sample container of the thermal analyzer according to claim 3, wherein the placement plate and the main body portion are made of the same material.

6. A sample container of the thermal analyzer according to claim 1 or 2, a heating furnace surrounding the periphery of the sample container and having an observation opening, and imaging means capable of observing the measurement sample through the observation opening; and comprising; A thermal analyzer characterized by measuring the thermal behavior accompanying temperature changes of the measurement sample in the heating furnace.

7. The thermal analyzer according to claim 6, wherein the thermal analyzer is a differential thermal analyzer, a differential scanning calorimeter, or a thermogravimetric analyzer.

8. The thermal analyzer according to claim 6, further comprising image processing means for generating predetermined color information from the image data of the measurement sample acquired by the imaging means, and superimposing and displaying the color information and the thermal behavior with respect to temperature.

Images