Particle size distribution measuring device and particle size distribution measuring method

Abstract

In order to provide a device for measuring particle diameter distribution in which the particle diameter distribution can be measured while changing the state of a specimen, the present invention is a device for measuring particle diameter distribution 100 comprising a light source LS that directs measurement light on a specimen accommodated inside a cell C equipped with a pair of translucent plates C1 that are separated from each other by a prescribed distance, one or more detectors D1, D2 that detect the measurement light scattered by the specimen, and a particle diameter distribution calculator P2 that calculates the particle diameter distribution of a group of particles included in the specimen S on the basis of output signals from the one or plurality of detectors D1, D2, wherein: the device 100 furthermore comprises a force-applying mechanism 1 that causes at least one of the pair of translucent plates to move and applies pressure or shear force to the specimen inside the cell; and the particle diameter distribution calculator P2 is configured so as to calculate the particle diameter distribution at a point in time when the pressure or shear force applied to the specimen S is changed from a first state to a second state.

Description

[Technical field]

[0001] The present invention relates to a particle size distribution measuring device that irradiates a sample with light and measures the particle size distribution of a particle group based on the light scattered by a particle group contained in the sample. [Background technology]

[0002] In a particle size distribution measuring device, when measuring a high-concentration, low-viscosity test liquid such as an undiluted ink solution, an optical measurement cell configured by sandwiching a spacer between a pair of light-transmitting plates is used as shown in Patent Document 1. In conventional particle size distribution measurements, for example, the state of the sample in the cell is made constant before the measurement is performed.

[0003] However, unlike the environment in which the particle size distribution is measured, the condition of the sample may change in the environment in which the sample is actually used. For this reason, conventional methods for measuring particle size distribution may not be an appropriate evaluation standard in an actual environment where the condition of the sample changes. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 2910596 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention has been made in consideration of the above-mentioned problems, and has an object to provide a particle size distribution measuring device that can measure particle size distribution while changing the state of a sample. [Means for solving the problem]

[0006] That is, the particle size distribution measuring device according to the present invention is a particle size distribution measuring device including: a light source that emits measurement light to a sample contained in a cell having a pair of light-transmitting plates spaced a predetermined distance from each other; one or more detectors that detect the measurement light scattered in the sample; and a particle size distribution calculator that calculates a particle size distribution of a particle group contained in the sample based on an output signal from the detector, and further includes a force applying mechanism that moves at least one of the pair of light-transmitting plates to apply a pressure or shear force to the sample in the cell, and the particle size distribution calculator is configured to calculate the particle size distribution at a time point when the pressure or shear force applied to the sample changes from a first state to a second state.

[0007] Further, a particle size distribution measuring method according to the present invention is a particle size distribution measuring method using a particle size distribution measuring device including: a light source that emits measurement light to a sample contained in a cell having a pair of light-transmitting plates spaced a predetermined distance from each other; one or more detectors that detect the measurement light scattered in the sample; and a particle size distribution calculator that calculates a particle size distribution of a particle group contained in the sample based on an output signal from the detector, characterized in that at least one of the pair of light-transmitting plates is moved to calculate the particle size distribution at a time when a pressure or shear force applied to the sample in the cell changes from a first state to a second state.

[0008] Such a device would enable the measurement of changes in particle size distribution in response to changes in pressure or shear force, allowing the evaluation of the state of particles in a sample under conditions close to the actual environment, and providing previously unobtainable insight into the sample.

[0009] Specific configuration examples of the force applying mechanism include a force applying mechanism configured to apply pressure to the sample in the cell by bringing the pair of light-transmitting plates closer to each other, or to apply a shear force to the sample in the cell by rotating one of the pair of light-transmitting plates relative to the other.

[0010] In order to continuously change the pressure applied to the sample even during measurement of the particle size distribution, the apparatus may further include a pressure-feeding unit that pumps the sample into the cell and changes the pressure of the sample in the cell.

[0011] If the particle size distribution calculator is configured to calculate the particle size distribution at each time point while an electric field or a magnetic field is being applied to the sample, the characteristics of the sample can be evaluated more accurately from changes in particle size distribution, even if the sample is used in an environment exposed to electromagnetic waves.

[0012] In order to enable evaluation of the process in which particles in a sample aggregate and then break up from the aggregated state from the measurement results of the particle size distribution when the particles in the sample are aggregated, it is sufficient that the particle size distribution calculator further includes an ultrasound application mechanism that applies ultrasound to the sample, and is configured to calculate the particle size distribution at each time point while ultrasound is being applied to the sample.

[0013] For example, in order to be able to evaluate the characteristics of a sample that hardens due to a photoreaction or changes over time due to a photoreaction from changes in particle size distribution, the device may further include an action light irradiator that irradiates the inside of the cell with action light that changes the state of the sample due to a photoreaction, and the particle size distribution calculator may be configured to calculate the particle size distribution at each time point while the sample is being irradiated with the action light.

[0014] In order to configure the entire particle size distribution measuring device compactly, the emission direction of the measurement light from the light source faces upward, a sample is placed above the light source, and one or more detectors are placed at positions where they can detect the measurement light scattered by the sample.

[0015] In order to be able to measure the particle size distribution of a sample even when it is dispersed without using a cell, the apparatus should include a sample stage, a measurement chamber in which one or more of the detectors are housed and the inside is kept at a predetermined pressure or vacuum, and an introduction mechanism that introduces a gas containing a powder sample from outside the container into the measurement chamber by the pressure difference between the inside and outside of the container.

[0016] In order to prevent contamination of the sample during particle size distribution measurement, the inside of the measurement chamber should be kept in a nitrogen atmosphere.

[0017] In order to easily perform other measurements such as observing the shape of the particles after the particle size distribution has been measured, it is sufficient that the sample stage is configured so that it can be used for observation with at least a microscope. Effect of the Invention

[0018] In this way, the particle size distribution measuring device of the present invention can measure changes in particle size distribution while changing the state of the particles contained in the sample by changing the pressure or shear force applied to the sample, thereby providing knowledge that could not be obtained by conventional particle size distribution measurements. [Brief description of the drawings]

[0019] [Figure 1] FIG. 1 is a schematic diagram showing a particle size distribution measuring device according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic perspective view of a cell in the first embodiment. [Diagram 3] FIG. 2 is a schematic cross-sectional view of a cell in the first embodiment. [Figure 4] 5 is a schematic diagram showing the relationship between a change in the state of pressure on a sample by a force applying mechanism and the timing of measuring a particle size distribution in the first embodiment. FIG. [Diagram 5] FIG. 4 is a schematic diagram showing a first modified example of the first embodiment. [Figure 6] FIG. 4 is a schematic diagram showing a second modified example of the first embodiment. [Figure 7] FIG. 11 is a schematic diagram showing a third modified example of the first embodiment. [Figure 8] FIG. 4 is a schematic diagram showing a particle size distribution measuring device according to a second embodiment of the present invention. [Explanation of symbols]

[0020] 100...Particle size distribution measuring device LS...Light source D1, D2... Detectors P2...Particle size distribution calculator 1. Force application mechanism 12 Fastening part T...Pulse feeding section 2...Action light irradiator 3. Ultrasonic application mechanism 4. Electromagnetic field application mechanism 5. Sample stage 6...Sealed box DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] A particle size distribution measuring device 100 according to a first embodiment of the present invention will be described with reference to Figures 1 to 3. The particle size distribution measuring device 100 according to the first embodiment is configured as a vertical device and is configured to be able to measure particle size distribution while changing the state of a sample S contained in a cell C. Here, the state of the sample S is changed by pressure, shear force, electric field, magnetic field, vibration, and photoreaction applied to the sample S.

[0022] As shown in FIG. 1, the particle size distribution measuring device 100 includes a light source LS that emits measurement light upward, a cell C that is arranged above the light source LS and contains a sample S therein, and a plurality of detectors D1 and D2 that detect the measurement light scattered by the sample S in the cell C, all of which are housed in a housing R. The light source LS emits laser light vertically upward as the measurement light. The plurality of detectors D1 and D2 are arranged on the optical axis of the light source LS and include a forward detector D1 that measures the measurement light transmitted through the cell C and four side detectors D2 that detect the measurement light scattered by the sample S. The forward detector D1 is arranged at a predetermined angle with respect to the optical axis of the light source LS to prevent the incident measurement light from being reflected and generating reflected light.

[0023] In addition, the particle size distribution measuring device 100 includes a CPU, a memory, an A / D converter, a D / A converter, and each input / output device, and also includes a computer COM connected to each device. The computer COM is configured to perform at least the functions of a controller P1 that controls the operation of each device and a particle size distribution calculator P2 that calculates the particle size distribution of a particle group contained in the sample S based on the output of each detector D1, D2 by executing a program for the particle size distribution measuring device stored in the memory.

[0024] In addition, this particle size distribution measuring device 100 is equipped with a force imparting mechanism 1 that applies pressure or shear force to the sample S, a pressure-feeding section T that pressure-feeds the sample S into the cell C, a light source LS that emits measurement light and an action light irradiator 2 that irradiates the sample S in the cell C with action light that causes a photoreaction, an ultrasonic vibration imparting mechanism 3 that imparts ultrasonic vibrations to the cell C, and an electromagnetic field imparting mechanism 4 that applies an electromagnetic field to the cell C.

[0025] The inside of the housing R is divided into two rooms. Specifically, a light source housing room R1 is formed in the lower part of the housing R, in which the light source LS and the actinic light irradiator 2 are housed. In addition, a measurement room R2 is formed in the upper part of the housing R, in which at least the cell C and the detectors D1 and D2 are housed.

[0026] As shown in Fig. 2 and Fig. 3, the cell C includes a pair of transparent plates C1 spaced apart from each other by a predetermined distance, and a spacer C2 between the transparent plates C1. The transparent plates C1 are formed in a roughly thin, circular shape, and an annular vapor-deposited film is formed on the outer periphery of the inner surface of one of the transparent plates C1 to form the spacer C2. One of the transparent plates C1 has two through holes penetrating in the thickness direction in a portion through which the measurement light does not pass, one of which is used as an introduction hole C3 for introducing the sample S between the transparent plates C1, and the other is used as an outlet hole C4 for leading the sample S from inside the transparent plates C1 to the outside. During measurement, the introduction hole C3 is connected to a pressure-feeding section T for pumping the sample S through a pipe, and the outlet hole C4 is covered with a sealing member C5.

[0027] A force applying mechanism 1 for applying pressure or shear force to the sample S contained inside the cell C is attached to the cell C. The force applying mechanism 1 in the first embodiment includes a clamping portion 12 for clamping a pair of light-transmitting plates C1 of the cell C in the thickness direction.

[0028] The fastening portion 12 clamps the pair of light-transmitting plates C1 of the cell C from the outside in the thickness direction. The fastening portion 12 of the first embodiment includes a first clamping element 12A having a housing portion 12C for housing the pair of light-transmitting plates C1, and a second clamping element 12B for clamping the pair of light-transmitting plates C1 between the first clamping element 12A. The pair of light-transmitting plates C1 are clamped by screwing the second clamping element 12B into the first clamping element 12A. By changing the fastening torque between the clamping elements, the pressure on the sample S contained therein can be changed. In addition, when the second clamping element 12B is screwed into the first clamping element 12A, a torque is generated in the light-transmitting plate C1 that contacts the second clamping element 12B, so that the shear force applied to the sample S contained therein can also be changed. That is, by rotating the second clamping element 12B relative to the first clamping element 12A, the light-transmitting plate C1 in contact with the second clamping element 12B can be rotated while the light-transmitting plate C1 placed on the first clamping element 12A is kept fixed, thereby generating a shear force on the sample S inside. Note that the state change of the pressure or shear force applied to the sample S by the fastening part 12 may be adjusted manually using a torque wrench or the like, or the pressure applied to the sample S may be accurately controlled by accurately controlling the separation distance between the pair of light-transmitting plates C1 using a machine such as a motor.

[0029] The pressure-feeding unit T is, for example, a pump that pumps the sample S into the cell C, and is configured so that the discharge rate is controlled by a controller P1 to change the pressure of the sample S pumped into the cell C.

[0030] For example, if the sample S is photocurable, the active light irradiator 2 irradiates ultraviolet light or the like as active light. The irradiation timing and irradiation time of the active light irradiator 2 are controlled by the controller P1.

[0031] The ultrasonic vibration imparting mechanism 3 is, for example, an ultrasonic vibrator attached to the cell C or the fastening portion 12. The oscillation timing and oscillation time of the ultrasonic vibrator are controlled by a controller P1. The amplitude and frequency of the ultrasonic vibration may be constant or may change over time.

[0032] The electromagnetic field applying mechanism 4 is a coil and electrodes that penetrate one of the light-transmitting plates C1 of the cell C in the thickness direction and are provided so as to be in partial contact with the sample S in the cell C. Since the electromagnetic field applying mechanism 4 is in contact with the sample S in this way, the particle size and other properties of the sample S can be sufficiently influenced by the electromagnetic field. The current flowing through the coil and the voltage applied to the parallel plate electrodes are controlled by a controller P1. The electric field or magnetic field applied to the cell C may be constant or may change over time.

[0033] The particle size distribution calculator P2 calculates the particle size distribution of the particle group in the sample S based on the output of each detector D1, D2. Specifically, the particle size distribution corresponding to the scattering pattern is calculated based on a scattering pattern consisting of the scattering angle and the intensity of the scattered light at the scattering angle indicated by the output of each detector D1, D2, and a predetermined theoretical calculation formula derived from the Mie scattering theory. Here, the particle size distribution calculator P2 is configured to calculate the particle size distribution at each time point over time while the state of the particles in the sample S is changing. Specifically, the particle size distribution is calculated while at least one of pressure, shear force, ultrasonic vibration, electric field, and magnetic field is applied to the cell C, or while the cell C is irradiated with actinic light.

[0034] According to the particle size distribution measuring device 100 of the first embodiment configured as described above, for example, the pressure applied to the sample S in the cell C can be changed from a first state at a certain reference time to a second state by the force applying mechanism 1, and the particle size distribution at the time when the pressure reaches the second state can be calculated. More specifically, as shown in FIG. 4(a), the force applying mechanism 1 can continuously change the pressure while measuring the change in particle size distribution at each time. Also, as shown in FIG. 4(b), the force applying mechanism 1 can change the pressure in a stepwise manner, and the particle size distribution during each step with a different pressure can be measured. Therefore, the relationship between the change in particle size distribution and the change in pressure can be obtained. For example, when a certain pressure is applied, it is possible to know that there is a bias in the particle size, or that when a certain pressure or more is applied, the aggregated particles are separated, and the desired particle size distribution can be obtained.

[0035] The dependence of particle size distribution on electric or magnetic fields can also be known.

[0036] By measuring the change in particle size distribution while applying ultrasonic vibrations to sample S, it is possible to know the time it takes for aggregated particles to separate, or the time it takes for the particles to degrade further from their current particle size and fall outside the particle size distribution.

[0037] By measuring the change in particle size distribution while irradiating the sample with actinic light, for example in the case of sample S that undergoes a photoreaction such as photocuring, it is possible to know from the change in particle size distribution what changes have occurred in the particle structure, etc. before and after the change.

[0038] A modification of the first embodiment will be described with reference to FIGS.

[0039] As shown in FIG. 5, the electromagnetic field applying mechanism 4 may be provided so as to block the inlet hole C3 and outlet hole C4 of the cell C, so as to be able to come into contact with the sample inside.

[0040] As shown in FIG. 6, the electromagnetic field applying mechanism 4 may be transparent electrodes provided opposite to each other on the inner surfaces of a pair of light-transmitting plates C1.

[0041] As shown in FIG. 7, the particle size distribution measuring device 100 is not limited to the one that measures the particle size distribution in a state where the sample S is accommodated in the cell C. For example, the powdered sample S may be dispersed on a glass plate using a sample dispersion device or the like, and the sample may be placed on a transparent sample stage 5 arranged at the position of the cell C in the first embodiment to perform measurement. In addition, a transparent sealed box 6 made of an acrylic or glass material may be provided in the measurement chamber R2 so as to accommodate the glass plate on which the sample S is dispersed and the sample stage 5, and the particle size distribution may be measured by creating a nitrogen atmosphere in the sealed box 6. In addition, it is also possible to measure the particle size distribution while changing the pressure applied to the sample S by controlling the pressure of the gas sealed in the sealed box 6 with a pump 7.

[0042] The force applying mechanism 1 may be configured to apply only pressure to the sample S in the cell C, or to apply only shear force. In order to apply only pressure to the sample S in the cell C, the force applying mechanism 1 may be configured to change only the distance between the pair of transparent plates C1 without rotating them. In addition, in order to apply only shear force to the sample S in the cell C, the force applying mechanism 1 may be configured to rotate at least one of the pair of transparent plates C1 while maintaining the distance between the pair of transparent plates C1. In addition, in the first embodiment, the force applying mechanism 1 is configured to move only the other transparent plate C1 while keeping one transparent plate C1 fixed, but the force applying mechanism 1 may move both transparent plates C1. In addition, the force applying mechanism 1 may be configured to move one transparent plate C1 so that the distance between the one transparent plate C1 can be changed, and rotate the other transparent plate C1 on the spot.

[0043] Next, a particle size distribution measuring device 100 according to a second embodiment will be described with reference to FIG.

[0044] In the second embodiment, instead of measuring the particle size distribution using a cell C, a sample S is dispersed in a measurement chamber R2 and attached to a sample stage 5 made of a transparent material in the measurement chamber R2.

[0045] In this embodiment, the inside of the measurement chamber R2 is maintained at a predetermined vacuum level by a suction source 9. An introduction mechanism 8 is provided on the outer wall of the measurement chamber R2 to introduce gas containing a powdered sample S from the outside of the container into the measurement chamber R2. The introduction mechanism 8 includes a partition film 81 that separates the inside and outside of the measurement chamber R2 and on which the powdered sample S is placed on the atmospheric side, a dome-shaped elastic cover 82 that is provided to cover the atmospheric side of the partition film 81, a needle member 83 that is provided in the elastic cover 82 to break the partition film 81, and a multi-stage nozzle 84 that is provided on the measurement chamber R2 side. By pushing the elastic cover 82, the partition film 81 is broken by the needle member 83, and the powdered sample S is sucked into the measurement chamber R2 by atmospheric pressure. At this time, the powdered sample S is repeatedly compressed and expanded by the multi-stage nozzle 84, and the aggregated parts are broken, and the powdered sample S is introduced into the measurement chamber R2 in a fine grain state. After that, the powdered sample S is sprayed onto the sample stage 5.

[0046] In this way, the particle size distribution measuring apparatus 100 of the second embodiment can deposit the powdered sample S in a state suitable for measuring the particle size distribution without using the cell C. In addition, since the particle size distribution measuring apparatus 100 is configured as a vertical type, it is possible to introduce the sample S under the assumption of gravity, and it is possible to realize a uniform dispersion suitable for measuring the particle size distribution on the sample stage 5.

[0047] A modification of the second embodiment will be described.

[0048] In preparation for the case where a powdered sample introduced into the measurement chamber R2 adheres to the detectors D1 and D2, a mechanism for removing the sample or dirt may be provided for each of the detectors D1 and D2.

[0049] The sample stage 5 may be configured so that it can be used not only for measuring particle size distribution but also for other measuring devices. For example, a marker for sharing coordinates may be formed on the sample stage so that particle shape observation can be performed immediately under a microscope. In addition, it may be used for various purposes such as optical analysis, Raman spectroscopic analysis, X-ray analysis, and electron beam analysis, in addition to the microscope.

[0050] Other embodiments will now be described.

[0051] The principle of measuring the particle size distribution is not limited to the static light scattering method, but may be the dynamic light scattering method.

[0052] In the embodiment, a vertical particle size distribution measuring device has been taken as an example, but even in the case of a particle size distribution measuring device in which each device is arranged in a horizontal plane, pressure, shear force, electric field, magnetic field, ultrasonic vibration, actinic light, or the like may be applied to a sample to change the state of the sample and measure changes in particle size distribution.

[0053] The pressure or shear force applied to the sample may be changed by, for example, utilizing the orientation of the cell. For example, the cell may be tilted obliquely from the horizontal state to change the direction of the force applied to the sample, thereby changing the state of the sample.

[0054] A temperature control mechanism may be provided around the cell, and the particle size distribution may be measured while changing the temperature of the sample.

[0055] In addition, various modifications of the embodiments and combinations of parts of each embodiment may be made without departing from the spirit of the present invention. [Industrial Applicability]

[0056] According to the present invention, it is possible to provide a particle size distribution measuring device that can measure changes in particle size distribution while changing the state of particles contained in a sample by changing the pressure or shear force applied to the sample.

Claims

1. A particle size distribution measuring device comprising: a light source that emits measurement light to a sample contained in a cell having a pair of light-transmitting plates spaced apart from each other by a predetermined distance; one or more detectors that detect the measurement light scattered by the sample; and a particle size distribution calculator that calculates a particle size distribution of a particle group contained in the sample based on an output signal of the detector, a force applying mechanism that applies pressure or shear force to the sample in the cell by moving at least one of the pair of light-transmitting plates; the force applying mechanism includes a clamping portion that clamps the pair of light-transmitting plates, and the clamping portion applies pressure, or pressure and shear force, to the sample by clamping the pair of light-transmitting plates; the particle size distribution calculator is configured to calculate a particle size distribution at a point in time when a pressure or shear force applied to a sample changes from a first state to a second state, based on a scattering pattern consisting of a scattering angle and an intensity of scattered light at the scattering angle.

2. 2. The particle size distribution measuring device according to claim 1, wherein the force applying mechanism is configured to apply pressure to the sample in the cell by bringing the pair of light-transmitting plates closer to each other, or to apply a shear force to the sample in the cell by rotating one of the pair of light-transmitting plates relative to the other.

3. 3. The particle size distribution measuring apparatus according to claim 1, further comprising a pressure-feeding unit that feeds a sample into the cell with pressure and changes the pressure of the sample in the cell.

4. Further comprising an electromagnetic field applying mechanism for applying at least one of an electric field and a magnetic field to the sample; 4. The particle size distribution measuring device according to claim 1, wherein the particle size distribution calculator is configured to calculate the particle size distribution at each time point in a state in which an electric field or a magnetic field is applied to a sample.

5. Further comprising an ultrasonic wave applying mechanism for applying ultrasonic waves to the sample, 5. The particle size distribution measuring device according to claim 1, wherein the particle size distribution calculator is configured to calculate the particle size distribution at each time point while ultrasonic waves are being applied to the sample.

6. The cell further includes an actinic light irradiator for irradiating the cell with actinic light that changes the state of the sample through a photoreaction, 6. The particle size distribution measuring device according to claim 1, wherein the particle size distribution calculator is configured to calculate the particle size distribution at each time point while the sample is irradiated with the actinic light.

7. The emission direction of the measurement light from the light source faces upward, 7. The particle size distribution measuring device according to claim 1, wherein a sample is placed above the light source, and the one or more detectors are placed at positions capable of detecting the measurement light scattered by the sample.

8. a measurement chamber in which a sample stage and one or more of the detectors are housed and whose interior is kept at a predetermined pressure or vacuum; 8. The particle size distribution measuring device according to claim 7, further comprising an introduction mechanism for introducing a gas containing a powder sample from outside the measurement chamber into the measurement chamber by using a pressure difference between the inside and outside of the measurement chamber.

9. 9. The particle size distribution measuring apparatus according to claim 8, wherein the inside of the measurement chamber is filled with a nitrogen atmosphere.

10. 10. The particle size distribution measuring apparatus according to claim 8, wherein the sample stage is configured so as to be usable at least for observation with a microscope.

11. A particle size distribution measuring method using a particle size distribution measuring device including: a light source that emits measurement light to a sample contained in a cell having a pair of light-transmitting plates spaced a predetermined distance from each other; one or more detectors that detect the measurement light scattered by the sample; and a particle size distribution calculator that calculates a particle size distribution of a particle group contained in the sample based on an output signal of the detector, by clamping the pair of light-transmitting plates, a pressure or a pressure and a shear force is applied to the sample, thereby moving at least one of the pair of light-transmitting plates; a scattering pattern consisting of a scattering angle and an intensity of scattered light at the scattering angle, the particle size distribution at a time point when a pressure or shear force applied to a sample in the cell changes from a first state to a second state is calculated based on the scattering pattern.

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