JP2005181006A - Measuring method of easily collapsible fine particles - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a measuring method of easily collapsible fine particles with a particle size of about 0.1-10 mm held in a wet state. <P>SOLUTION: A dispersing liquid 2 is added to a fine particle group 1 to disperse the fine particle group having coagulable properties in a wet state. Further, the fine particle group dispersed so that the fine particles 1a are arranged on a measuring plate 10 in a one-layer state to measure the respective particles of the fine particle group on the basis of imaging data. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for measuring fine particles, and more particularly to a method for measuring easily disintegrating particles made of agar or the like in a wet state with a diameter of about 0.1 mm to about 10 mm.

  As a method for measuring the size, shape, number, etc. of wet granular materials, a photoelectric sensor mechanism is arranged below the multiple nozzle, and the core liquid and coating liquid are ejected from the multiple nozzle into the liquid and dropped. There is a method of detecting the light shielding of the capsule formed by the above-mentioned photoelectric sensor mechanism and measuring the size and number of the capsules from the light shielding time and the number of times of light shielding (for example, see Patent Document 1).

Further, as a method for obtaining the particle size, shape, etc. in the dry granular material, the particle size is dispersed by dispersing the granular material on a flat surface, and then image processing is performed on image data obtained by imaging the granular material. (For example, refer to Patent Document 2).
JP-A-4-322740 JP 2003-130785 A

However, in the measurement method described in Patent Document 1, it is necessary to measure at least about 1000 particles in order to obtain accurate data. Further, since only one particle can be measured per measurement, there is a problem that it takes a long time to measure the number.
In the method described in Patent Document 2, when the granular material is arranged in a plurality of layers on the flat surface, the distance between the granular material in each layer and the camera that performs imaging is different and focusing is difficult. Therefore, accurate image data cannot be obtained. Therefore, there is a problem that the granular material must be dispersed on the flat surface.

  Further, when the method of Patent Document 2 is applied to wet particles, the wet particles aggregate with each other due to the surface tension of the liquid, and thus it is more difficult to further disperse on the flat surface. Become. In addition, it is conceivable to use a squeegee or the like to make the granular material one layer, but in the case of an easily disintegrating granular material, the particles are crushed by squeezing, so it is very difficult to make it even further. is there.

  Furthermore, as a method for measuring fine particles, there is generally a method for measuring the particle size by analyzing using a laser beam. However, the measurement method is limited to the measurement of ultrafine particles, and in particular, particles having a particle diameter of 0.1 mm or more cannot be measured with high accuracy.

  The present invention has been made in order to solve the above-described problems, and provides a fine particle measurement method for measuring fine particles which are wet and have a particle size of about 0.1 mm to about 10 mm and are easily disintegratable. The purpose is to provide.

In order to achieve the above object, the present invention is configured as follows.
That is, according to the easily disintegratable fine particle measuring method of the first aspect of the present invention, a measurement object obtained by adding a dispersion liquid to a disintegratable and wet fine particle group is placed on a measurement plate,
Dispersing the fine particle group in the dispersion liquid so that each particle of the fine particle group is arranged in a layer on the measurement plate,
The dispersed fine particle group is imaged, and the particles are measured based on the imaging data.

  Further, according to the easily disintegratable fine particle measuring method of the second aspect of the present invention, the dispersion liquid is adjusted so that the weight of the dispersion liquid is 0.4 times or more with respect to the weight of the fine particle group. And the dispersion liquid so that the contact angle between the measurement plate and the measurement object at the peripheral edge of the measurement object placed on the measurement plate is 40 degrees or less. The above fine particle group is dispersed.

  Moreover, according to the easily disintegrating fine particle measuring method of the third aspect of the present invention, the dispersion liquid contains a surfactant having a contact angle of 40 degrees or less.

  In addition, according to the easily disintegratable fine particle measuring method of the fourth aspect of the present invention, the object to be measured placed on the measuring plate is disposed on the measuring plate in order to arrange the particles in a single layer. Vibration or rocking is given to.

  Moreover, according to the easily disintegratable fine particle measuring method of the fifth aspect of the present invention, the particles are hydrogel.

  Moreover, according to the easily disintegratable fine particle measuring method of the sixth aspect of the present invention, the lower limit of the particle diameter of the particles is 0.1 mm, and the upper limit is 10 mm.

  According to the measurement method described above, by adding the dispersion liquid to the fine particle group, the coherent wet fine particle group can be dispersed, and further arranged on the measurement plate in one layer. It is possible to measure each particle of the fine particle group based on the imaging data. In addition, since the dispersion of the fine particle group is achieved by adding the above-described dispersion liquid, it is not necessary to further divide the fine particle group using a squeegee or the like. Measurement is possible.

  A method for measuring fine particles according to an embodiment of the present invention will be described below with reference to the drawings. Each figure is one example of the method for measuring fine particles of the present invention, and the same reference numerals are given to the same components in each figure.

  The measurement method of the present embodiment is a measurement of a granular material that is easily collapsed and wet and is likely to aggregate particles due to being wet. Specifically, for example, counting the number of particles, Suitable for diameter measurement, particle size measurement, particle size, size and shape measurement, particle surface property measurement and the like. The granular material has a compressive breaking strength of 2 to 500 kPa. Specifically, the diameter produced using agar or gelatin is 0.1 mm to 10 mm, particularly 0.3 mm to 5 mm. This is a hydrogel particle. Such hydrogel particles are mixed in a viscous liquid in, for example, cosmetics.

  As described above, since the granular material to be measured has high cohesiveness, the feature point in the measurement method of the present embodiment is to further disperse fine particle groups that are easily disintegratable and highly cohesive. In the embodiment, the dispersion is achieved by adding a dispersion liquid to the fine particle group. As the dispersion liquid, a liquid having a surface tension lower than that of water is preferably used. For example, ethanol or a cleaning solution containing a surfactant is suitable. The addition ratio of the dispersion liquid to the fine particle group is preferably 0.4 times or more by weight of the dispersion liquid with respect to the weight of the fine particle group, from the viewpoint of facilitating the dispersion of the fine particle group. Is more preferably 0.5 times or more.

  On the other hand, as shown in FIG. 4, a measurement object 3 in which a dispersion liquid 2 is added to a fine particle group 1 made up of a plurality of fine particles 1a is placed on a measurement plate 10 and, as will be described later, the measurement object. The fine particles 1a are measured by imaging the object 3. Therefore, the weight ratio has an upper limit from the viewpoint of performing the imaging operation satisfactorily. That is, for example, when the fine particle group 1 is placed in a finite region such as a petri dish and the dispersion liquid 2 is added for measurement, the dispersion liquid exceeds the diameter of the fine particle group 1 in the thickness direction of the bottom plate of the petri dish. When 2 is present, that is, when the fine particle group 1 is completely immersed in the dispersion liquid 2, fine particles may float, and it is difficult to focus on the fine particles 1a during the imaging. Therefore, there is a concern that appropriate imaging information cannot be obtained. Accordingly, the weight ratio is 0.4 times or more, and as shown in FIG. 5, the dispersion is performed in such an amount that the depth in the thickness direction 11 of the measurement plate 10 is not more than the diameter D of the fine particles 1a. It is preferable to add the working solution 2.

  As shown in FIG. 4, when the measurement object 3 is placed on the measurement plate 10, the tangent to the liquid surface 3 b of the measurement object 3 in the peripheral portion 3 a of the measurement object 3 and the measurement object 3 It is preferable to add the dispersion liquid 2 to the fine particle group 1 so that the contact angle θ formed with the surface 10a of the measurement plate 10 in contact is 40 degrees or less. By making the weight ratio 0.4 times and further making the contact angle θ 40 degrees or less, the fine particle group 1 is dispersed, and the fine particles 1a do not overlap in the thickness direction 11 of the plate 10 to be measured. It becomes possible to arrange in one layer. In the case where the DUT 3 is provided in a finite region, the above-mentioned condition “depth equal to or smaller than the diameter D of the fine particles 1a” is further added.

  In order to set the contact angle θ to 40 degrees or less, it can be achieved by using a liquid having a surface tension lower than that of water as a dispersion liquid as described above. For example, by adding a surfactant to water. Achievable.

  As will be described later, the object to be measured 3 placed on the measurement plate 10 is imaged by an imaging camera. Therefore, the measurement plate 10 is preferably made of a translucent material, for example, glass. Is preferred. Furthermore, in order to facilitate the dispersion of the fine particle group 1 and arrange the fine particles 1a in a single layer, it is preferable to apply vibration or swing to the measurement plate 10 on which the object to be measured 3 is placed.

A measurement apparatus that performs measurement on the DUT 3 placed on the measurement plate 10 as described above will be described below. In the measurement object 3, the dispersion liquid 2 is added to the fine particle group 1 in advance under the above-described conditions, and the fine particle group 1 is in a state where each fine particle 1a is further dispersed.
As shown in FIG. 1, the measurement apparatus 100 includes a placement unit 110 on which a flat measurement plate 10 on which the measurement object 3 is placed and a measurement unit placed on the placement unit 110. An imaging camera 120 that is disposed above the plate 10 and images the object to be measured 3, and an analysis device 130 that is connected to the imaging camera 120 and measures the fine particles 1 a based on imaging data transmitted from the imaging camera 120. Prepare.

  The placement unit 110 includes an illumination device 111 having a plate-like light source on which the measurement plate 10 is placed. The illumination device 111 projects light from the back surface 10 b side facing the front surface 10 a of the measurement plate 10, and supplies the imaging light to the imaging camera 120 through the measurement plate 10 and the object to be measured 3. In this way, by imaging with transmitted light, the influence of the color of the fine particles 1a is small, and it is possible to obtain imaging data that highlights the shadow of the fine particles 1a, and the particle extraction accuracy during image processing is improved. . In addition, the configuration can be simplified by using a plate-like light source. The plate-shaped light source is not particularly limited as long as it can irradiate the photographing region uniformly in practice, and an LED light source, a unit for cold lamp, a fluorescent light box using a diffusion plate on the upper surface, etc. are used. it can. An LED light source is preferable in terms of uniform irradiation and device simplification.

  The imaging camera 120 is preferably a CCD camera, but a TV camera, a microscope, or the like can also be used.

  For example, a personal computer can be used as the analysis device 130, and general-purpose image analysis software and general-purpose spreadsheet software for calculating the granularity and the like are installed. Therefore, the analysis device 130 stores the imaging data 121 shown in FIG. 2 from the imaging camera 120, performs binarization processing and noise removal processing on the imaging data 121, and obtains image processing data 122. Based on the image processing data 122, the analysis device 130 performs, for example, the following measurement processes. That is, the shape identification and counting of the fine particles 1a are performed, the area, perimeter length, and particle size of the projection image of each fine particle 1a on the two-dimensional plane are obtained, and the obtained projection data is stored. Further, evaluation information representing the particle size of the fine particles 1a is obtained from the projection data. For example, the analysis device 130 obtains the particle size distribution by counting the number of fine particles 1a present for each peripheral length range of the arbitrarily defined fine particles 1a. Moreover, the analysis apparatus 130 calculates | requires the evaluation information showing the shape characteristic of each fine particle 1a from the said projection data and the shape parameter which is a known dimension common to each fine particle 1a.

  According to the measuring apparatus 100 described above, the fine particles 1a in the fine particle group 1 of the measurement object 3 are in a state of being further dispersed in advance by the dispersion liquid 2 as described above. In addition, since the focusing operation by the imaging camera 120 can be easily performed, and the imaging data supplied to the imaging camera 120 is not in a state in which the plurality of fine particles 1a overlap in the thickness direction 11 of the measurement plate 10, Individual fine particles 1a can be clearly recognized. Therefore, the number, particle size, particle size distribution, and shape of the fine particles 1a can be accurately obtained. In addition, since each fine particle 1a is in a state of being further dispersed by the dispersion liquid 2 in advance as described above, it is not necessary to arrange it further using a squeegee or the like. Therefore, even when measuring collapsible particles that are easily crushed, for example, hydrogel particles, measurement can be performed without crushing the particles, and the above-described number and particle size distribution can be accurately obtained.

  Further, since the imaging data in a state where the fine particle group 1 is dispersed and arranged in one layer as described above can be obtained, the physical properties of the fine particles 1a such as the above-mentioned particle number measurement and particle size measurement based on the image data are obtained. In addition to the measurement, the following measurement is also possible. For example, it is possible to determine the presence / absence of a state in which a plurality of fine particles 1a are combined, or to measure the size, size, shape, etc. of the fine particles 1a as described above. The ratio of the fine particles 1a to the whole is obtained, the surface properties of the fine particles 1a are measured, and the above measurement results are fed back to the fine particle production apparatus for producing the fine particles 1a to produce the fine particles 1a. It is also possible to make the conditions more appropriate. The measurement operation executed with reference to the imaging data is executed by software that performs image analysis. Therefore, the measurement target can be changed by selecting the image analysis software. Therefore, the measurement object is not limited to the above items.

  Next, with reference to FIG. 3, a measurement system 150 including the above-described measurement apparatus 100 will be described below.

  The measurement system 150 includes a sample stocker 160, a dispersion liquid tank 170, a dispersion device 180, and a control device 190 in addition to the measurement device 100.

  The sample stocker 160 is a part for storing the fine particle group 1, and the fine particle group 1 is supplied to the sample stocker 160 independently of other devices, or a separate fine particle production apparatus. 200. The dispersion liquid tank 170 is a tank that stores the dispersion liquid 2 described above, and an appropriate amount of the dispersion liquid 2 is supplied to the sample stocker 160 via the pump 171. The supply amount of the dispersion liquid 2 is obtained by the control device 190 based on the above-mentioned ratio with respect to the weight of the fine particle group 1 supplied to the sample stocker 160, and the appropriate amount of the dispersion liquid 2 obtained is supplied. As described above, the control device 190 drives the pump 171. Note that the supply amount of the dispersion liquid 2 is not limited to the above weight ratio, but also takes into consideration the above-mentioned conditions of “contact angle θ of 40 degrees or less” and further “depth of diameter D or less of fine particles 1a”. Can also be determined.

  The dispersing device 180 is a device that disperses the fine particle group 1 in the measurement object 3 in which an appropriate amount of the dispersion liquid 2 is added to the fine particle group 1, and the sample stocker 160 is disposed in the vicinity of one end. In the vicinity of the other end, the measuring plate 10 provided in the measuring apparatus 100 is disposed. In the present embodiment, the dispersion device 180 is configured by a vibration feeder or a conveyor with a swing function. Therefore, the DUT 3 supplied from the sample stocker 160 to the one end is moved to the other end while the fine particle group 1 is dispersed by vibration or the like, and supplied to the surface 10 a of the measurement plate 10. In the object to be measured 3 supplied to the measurement plate 10, the fine particle group 1 is sufficiently dispersed by the vibration or the like, and the fine particle 1 is in a single layer state on the surface 10a. The operation of the distribution device 180 is also controlled by the control device 190.

  After the measurement object 3 is supplied to the measurement plate 10, the measurement apparatus 100 captures the measurement object 3, stores the image data, performs image processing, measures the fine particles 1a, and records the measurement data, as described above. Etc.

  The measurement plate 10 is inclined or configured to be inclined at the time of discharge so that the DUT 3 supplied to the measurement plate 10 is naturally moved to the sample receiver 185 and discharged. It is preferable. Note that the DUT 3 supplied to the sample receiver 185 can be returned to the manufacturing process of the product containing the fine particles 1.

  As described above, according to the present measurement system 150, the object to be measured 3 can be automatically produced, and further, the fine particle group 1 can be automatically dispersed. Acquisition can be performed very easily.

  Although the measurement system 150 includes the dispersion liquid tank 170 and the measurement object 3 is produced by the sample stocker 160, the measurement object 150 is not limited to the configuration of the apparatus, and the measurement object prepared by adding the dispersion liquid 2 in advance. The measurement object 3 may be supplied to the dispersion device 180.

(Manufacture of fine particles)
0.5% by weight agar (trade name: T-1 manufactured by Ina Food Industry Co., Ltd.), 0.3% by weight methyl paraoxybenzoate, 0.3% by weight polyoxyethylene lauryl ether phosphorus in ion-exchanged water Sodium acid (trade name: SPE104NB, manufactured by Kao Corporation) was added and dissolved by heating to 80 ° C. The solution was discharged at a flow rate of 10 ml / min into an oil (methylpolysiloxane: manufactured by Shin-Etsu Chemical Co., Ltd., trade name: Silicone KF-96A (20CS)) cooled to 10 ° C. from a nozzle having a diameter of 1.2 mm. After solid-liquid separation, the oil on the particle surface was removed by washing with water to obtain hydrogel particles.

(Dispersion solution)
The following two types of dispersion solutions were used.
A: Ion exchange water Commercial ion exchange water (surface tension 73 mN / m) was used as it was.
B: Activator mixed solution A 0.2% by weight aqueous solution of alkyl ether sulfate sodium (trade name: Family Fresh 0.63 g, water 60.58 g added) was used.

(Measurement plate)
A commercially available acrylic plate and glass plate were used as the measurement plate.

(Example 1)
About 0.65 g of the hydrogel particles obtained by the above method were collected, arranged so that the multilayers overlapped on the measurement plate, and ion-exchanged water and an activator mixture (sodium alkyl ether sulfate 0.2 wt. % Aqueous solution) was added to the hydrogel particles in an amount corresponding to 0.1 to 1.0 times by weight. Thereafter, the measurement plate was reciprocated 20 times in the horizontal direction, and the dispersion state was observed. Further, the contact angle between the measurement plate and the dispersion solution was measured. The results are shown in Table 1. In Table 1, “x” indicates that fine particles are not dispersed and one layer is not arranged, “Δ” indicates that a part of fine particles remain without being arranged in one layer, and “◯” indicates all fine particles. Indicates that one layer is arranged.

  In the case of using ion-exchanged water as a dispersion liquid and using an acrylic plate as a measurement plate, the contact angle of the liquid is 72 °, agglomerates regardless of the amount of the liquid, remains in a multi-layer arrangement, I couldn't. On the other hand, in the case of using ion-exchanged water as a dispersion liquid and a glass plate as a measurement plate, the contact angle of the liquid is 35 °, and all fine particles are further removed when the liquid amount is 50% by weight or more. Could be arranged. In the case of using an active agent mixture as a dispersion liquid and an acrylic plate as a measurement plate, the contact angle of the liquid is 12 °, and all fine particles are arranged in one layer when the liquid amount is 50% by weight or more. Became. In the case of using an active agent mixture as a dispersion liquid and a glass plate as a measurement plate, the contact angle of the liquid is 8 °, and all fine particles are arranged in a single layer when the liquid amount is 50% by weight or more. Became.

(Example 2)
The hydrogel particles arranged in a single layer on the measurement plate were photographed and image analysis was attempted. First, hydrogel particles were dispersed under the conditions that can be arranged in one layer in Example 1 above. That is, 1.67 g of the hydrogel particles obtained by the method for producing fine particles is placed on an acrylic plate, and 0.84 g of the above is added so that the weight ratio of the dispersion liquid to the fine particles is 0.5 times. The activator mixture was added. The contact angle between the acrylic plate and the activator mixture was 12 °. Thereafter, the measurement plate was swung back and forth 20 times in the horizontal direction, and the state was observed. FIG. 6 shows a state before swinging, and FIG. 7 shows a state after swinging. The fine particles were arranged in a single layer after 20 reciprocating oscillations. A photograph taken for image analysis in this state is shown in FIG.

  When the particle size distribution was analyzed with the image analysis software “WinROOF” (trade name, manufactured by Mitani Corporation) using the photograph of FIG. 8, 1650 particles in the field of view were separated and measured as independent particles. Was possible.

(Comparative example)
An image analysis was attempted by photographing hydrogel particles that were not arranged in a single layer on the measurement plate. First, the hydrogel particles were dispersed under the condition that the arrangement in Example 1 was not a single layer. That is, 1.36 g of the hydrogel particles obtained by the above-mentioned “fine particle production method” are placed on an acrylic plate, and 0.69 g so that the weight ratio of the dispersion liquid to the fine particles is 0.5 times. Was added as a dispersion liquid. The contact angle between the acrylic plate and the 10 wt% ethanol aqueous solution was 61 °. Thereafter, the measurement plate was swung back and forth 20 times in the horizontal direction, and the state was observed. FIG. 9 shows a state before swinging, and FIG. 10 shows a state after swinging. The fine particles were agglomerated and there were portions arranged in multiple layers. A photograph taken for image analysis in this state is shown in FIG.

  In the photographed image, the outline of the particles was not clear in the part where the fine particles overlapped. When the photographed photograph was analyzed for particle size distribution with image analysis software “WinROOF” (trade name, manufactured by Mitani Corporation), only 272 particles could be separated and measured from the particles in the field of view. .

  The easily disintegrating fine particle measuring method of the present invention can be used for measuring GAP particles contained in cosmetics, for example.

It is a perspective view which shows the structure of the measuring apparatus which measures a fine particle using the fine particle measuring method in embodiment of this invention. It is a figure which shows the imaging data and image processing data which are obtained in the measuring apparatus shown in FIG. It is a figure which shows the structure of the measurement system provided with the measuring apparatus shown in FIG. It is a figure which shows the to-be-measured object measured with the measuring apparatus shown in FIG. It is a figure for demonstrating the relationship between the fine particle in the to-be-measured object measured with the measuring apparatus shown in FIG. 1, and the liquid for dispersion | distribution. It is a photograph which shows the state before adding a hydrogel particle and an activator liquid mixture, and before rocking | fluctuation. It is a photograph which shows the state after rocking | fluctuation after adding a hydrogel particle and an activator liquid mixture. It is the photograph which image | photographed the state of FIG. 7 for image analysis. It is a photograph which shows the state before a rocking | fluctuation after adding a hydrogel particle and ethanol aqueous solution. It is a photograph which shows the state after rocking | fluctuation after adding a hydrogel particle and ethanol aqueous solution. It is the photograph which image | photographed the state of FIG. 10 for image analysis.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Fine particle group, 1a ... Fine particle, 2 ... Dispersion liquid, 3 ... To-be-measured object, 3a ... Peripheral part,
10: Measuring plate.

Claims (6)

An object to be measured (3) obtained by adding the dispersion liquid (2) to the easily disintegrating and wet fine particle group (1) is placed on the measurement plate (10),
The fine particle group is dispersed in the dispersion liquid so that each particle (1a) of the fine particle group is arranged in a layer on the measurement plate,
The dispersed fine particle group is imaged, and the particles are measured based on the imaging data.
A method for measuring easily disintegrating fine particles.   The object to be measured, which is added to the fine particle group and placed on the measurement plate so that the weight of the dispersion liquid is 0.4 times or more with respect to the weight of the fine particle group. The fine particles are dispersed in the dispersion liquid so that the contact angle (θ) between the measurement plate and the object to be measured at the peripheral edge (3a) of the dispersion is 40 degrees or less. Of easily disintegrating fine particles.   The method for measuring easily disintegrable fine particles according to claim 2, wherein the dispersion liquid contains a surfactant having a contact angle of 40 degrees or less.   4. The apparatus according to claim 1, wherein the particles to be measured placed on the measurement plate are vibrated or oscillated in order to arrange the particles on the measurement plate in a single layer. 5. Of easily disintegrating fine particles.   The method for measuring easily disintegrable fine particles according to claim 1, wherein the particles are made of hydrogel. The particle size of the particles is a method for measuring easily disintegrable fine particles according to any one of claims 1 to 5, wherein the lower limit is 0.1 mm and the upper limit is 10 mm.

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