Standard solution for blood cell counter calibration

Abstract

To provide a standard solution for blood cell counter calibration, which offers superior calibration accuracy and storage stability.SOLUTION: A standard solution for blood cell counter calibration is provided, the solution containing resin particles having an average circularity of 0.99 or less and a volume average particle diameter of 2 μm or more and 10 μm or less.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a standard solution for calibrating a hemocytometer. [Background technology]

[0002] Knowing the hemoglobin concentration in blood is important for predicting and understanding the severity of illness, and is a major item in blood tests. Hemoglobin concentration is measured using a hemocytometer that uses a particle size measurement method such as the Coulter method or the electrical detection zone method. This hemocytometer must be highly calibrated to accurately measure hemoglobin concentration.

[0003] To calibrate this blood cell counter, a calibration standard solution in which resin particles are dispersed in an activator solution is used. However, the shape of the resin particles dispersed in these blood cell counter calibration standard solutions is spherical, which is different from the flat shape of human red blood cells. Therefore, the measurement of hemoglobin concentration using conventional blood cell counters does not provide sufficient calibration accuracy (see, for example, Patent Document 1). Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a standard solution for calibrating a hemocytometer, which has excellent calibration accuracy and storage stability. [Means for solving the problem]

[0005] In order to solve the above-mentioned problems, one aspect of the present invention is a standard solution for calibrating a blood cell counter containing blood resin particles, wherein the average circularity of the resin particles is 0.99 or less and the volume average particle size of the resin particles is 2 μm or more and 10 μm or less. Effect of the Invention

[0006] According to one aspect of the present invention, a standard solution for calibrating a hemocytometer having excellent calibration accuracy and storage stability can be obtained. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] An embodiment of the present invention will now be described in detail.

[0008] <Standard solution for calibrating hemocytometers> The standard solution for calibrating a blood cell counter according to the present embodiment contains resin particles. In this specification, a blood cell counter refers to a device for measuring the hematocrit value of human blood. The hematocrit value indicates the ratio of the total volume of red blood cells to the total volume of blood, and is a test item used for diagnosing anemia, etc. Examples of methods for measuring the hematocrit value include the centrifugation method and the Coulter method.

[0009] In the centrifugation method, about 1 ml of blood to which an anticoagulant has been added is taken into a capillary pipette, the tip of the pipette is inserted to the bottom of a Wintrobe tube, and while slowly removing the blood, the tube is filled up to the "0" mark, centrifuged, and the hematocrit value is calculated from the percentage of the red blood cell volume that is occupied by the red blood cells. In this centrifugation method, the volume of red blood cells is read directly after centrifugation, so the hematocrit value can accurately reflect differences in the shape of red blood cells.

[0010] The Coulter method allows automatic measurement of hematocrit, and hemocytometers incorporating the Coulter technology are widely used. The Coulter technology is a counting technique that relies on measuring the impedance variations in a measurement cell when one or more particles are guided through it during flow. The number of impedance changes indicates the number of particles in the fluid, while the measured impedance value is proportional to the volume of the particles in the fluid.

[0011] Specifically, in the Coulter method, a wall having a single through hole is provided in an electrolyte in which particles are dispersed, electrodes are placed on both sides, and while a constant current is applied through the hole, the electrolyte is sucked from the inside of the hole with a constant suction force, so that the particles pass through the hole together with the electrolyte. At this time, the electrolyte in the hole is reduced by an amount equivalent to the volume of the particles, and the electrical resistance of the hole becomes larger in proportion to the amount of electrolyte removed.

[0012] The current flowing through the pore is constant regardless of the presence of particles, so the amount of voltage change is proportional to the amount of change in the electrical resistance of the pore. The volume of the particles is measured from the amount of change in voltage, and the spherical equivalent diameter of the particles is calculated from this volume, and the particle size distribution is displayed. The number of particles that pass through the pores is also counted by counting the voltage change. In other words, the Coulter method can quantitatively measure the blood cell concentration and hematocrit value in blood.

[0013] However, in conventional standard solutions for calibrating blood cell counters, the dispersed resin particles (hereinafter referred to as dispersed particles) are spherical, and therefore blood cell counters using an electrical detection zone method such as the Coulter method cannot accurately determine the particle volume of dispersed particles that are flat and non-spherical, such as human red blood cells.

[0014] In this embodiment, the average circularity of the resin particles contained in the standard solution for calibrating a hemocytometer is set to 0.99 or less, preferably 0.90 to 0.987, and more preferably 0.95 to 0.985. In this specification, the average circularity is a value obtained by optically detecting a particle and dividing the particle by the perimeter of a circle having the same projected area.

[0015] When the average circularity of the resin particles contained in the standard solution for calibrating a hemocytometer is 0.99 or less, the shape of the resin particles becomes close to the shape of hemoglobin, and the standard solution for calibrating a hemocytometer can have a particle shape that provides excellent measurement accuracy and storage stability.

[0016] If the average circularity exceeds 0.99, the resin particles are close to a perfect sphere, which may reduce the measurement accuracy of the standard solution for calibrating a blood cell counter. If the average circularity is less than 0.90, the dispersed particles in the standard solution for calibrating a blood cell counter may have a shape far removed from a sphere, which may reduce the measurement accuracy. For this reason, the average circularity is preferably 0.90 or more.

[0017] In the standard solution for calibrating a blood cell counter of this embodiment, the resin particles contained in the standard solution for calibrating a blood cell counter have a volume average particle size of 2 μm to 10 μm, preferably 1.5 μm to 9 μm, and more preferably 3 μm to 8 μm. Here, the volume average particle size refers to the particle size at the point where the cumulative volume is 50% when the cumulative volume particle size distribution curve is calculated with the total volume of the particles being 100%.

[0018] When the volume average particle diameter of the resin particles contained in the standard solution for calibrating a blood cell counter is 2 μm or more and 10 μm or less, the storage stability of the standard solution for calibrating a blood cell counter can be stabilized. If the volume average particle diameter is less than 2 μm, the resin particles tend to aggregate in the standard solution for calibrating a blood cell counter, and dispersibility may decrease. If the volume average particle diameter is more than 10 μm, the resin particles tend to settle in the standard solution for calibrating a blood cell counter, and dispersibility may decrease.

[0019] In the standard solution for calibrating a hemocytometer of this embodiment, the coefficient of variation of the particle size of the resin particles is preferably 15% or less, more preferably 13% or less, and even more preferably 11% or less. In this specification, the coefficient of variation of the particle size is expressed as a percentage by dividing the standard deviation of the particles by the average particle size of the particles. Here, the average particle size is the particle size at which the cumulative distribution on a volume basis measured by a laser diffraction / scattering method is 50%.

[0020] When the coefficient of variation of the particle size of the resin particles contained in the standard solution for calibrating a hemocytometer is 15% or less, the shape of the resin particles becomes closer to the shape of hemoglobin, thereby improving the measurement accuracy of the standard solution for calibrating a hemocytometer.

[0021] If the coefficient of variation of the particle size exceeds 15%, the shape of the resin particles will be far removed from the shape of hemoglobin, which may result in poor measurement accuracy. Although there is no lower limit for the coefficient of variation of the particle size, it is sufficient that the coefficient of variation is at least 1%.

[0022] In this embodiment, the aspect ratio of the resin particles contained in the standard solution for calibrating a hemocytometer is preferably 1.3 or more and 5.0 or less, more preferably 1.4 or more and 4.8 or less, and even more preferably 1.5 or more and 4.5 or less. In this specification, the aspect ratio refers to the ratio of the length of the longest side (major axis) to the length of the shortest side (minor axis), and the larger this value, the higher the irregularity of the resin particles.

[0023] When the aspect ratio of the resin particles contained in the standard solution for calibrating a hemocytometer is greater than 1.3 and not greater than 5.0, the shape of the resin particles becomes closer to the shape of hemoglobin, thereby further improving the measurement accuracy of the standard solution for calibrating a hemocytometer.

[0024] If the aspect ratio is less than 1.3, the resin particles are nearly spherical, which may reduce the measurement accuracy of the standard solution for calibrating a blood cell counter.If the aspect ratio is more than 5.0, the shape of the resin particles will be far removed from the shape of hemoglobin, which may reduce the measurement accuracy.

[0025] In the standard solution for calibrating a blood cell counter according to the present embodiment, the resin particles have carboxyl groups on their surfaces. The resin particles having carboxyl groups on their surfaces are not particularly limited. As the resin particles having carboxyl groups on their surfaces, for example, low molecular weight polyester is preferable.

[0026] In this embodiment, the resin particles contained in the standard solution for calibrating a blood cell counter have carboxyl groups on their surfaces, thereby improving the storage stability of the standard solution for calibrating a blood cell counter and improving the dispersion stability of the resin particles in the standard solution for calibrating a blood cell counter.

[0027] In the standard solution for calibrating a blood cell counter according to the present embodiment, the density of the carboxyl groups on the surface of the resin particles is 0.001 particles / Å 2 In this specification, the density of carboxyl groups on the surface of the resin particles is calculated from the content of carboxyl groups in the resin converted from the acid value of the resin based on the standard of JIS K0070 (1992).

[0028] In the standard solution for calibrating a blood cell counter according to the present embodiment, the density of the carboxyl groups on the surface of the resin particles is 0.001 particles / Å 2 If the amount is more than this, the dispersibility of the resin particles in the standard solution for calibrating a hemocytometer is increased, and the calibration accuracy and storage stability of the standard solution for calibrating a hemocytometer can be improved.

[0029] The content of resin particles in the standard solution for calibrating a hemocytometer is preferably 1.0 to 10 mass%, more preferably 1.5 to 7.5 mass%, and even more preferably 2.5 to 5.0 mass%, relative to 100 mass% of the standard solution for calibrating a hemocytometer.

[0030] By setting the content of resin particles in the standard solution for calibrating a hemocytometer to 1.0% by mass or more, the cold resistance of the resin particles is increased, and the storage stability of the standard solution for calibrating a hemocytometer can be improved. Also, by setting the content of resin particles having carboxyl groups on their surfaces to 10% by mass or less, the dispersion stability of the resin particles in the standard solution for calibrating a hemocytometer can be improved.

[0031] <Resin particles and their manufacturing method> Here, an example of the resin particles (dispersed particles) contained in the standard solution for calibrating a hemocytometer of this embodiment will be described. The resin particles can be produced by the following method. First, a polyol and a polycarboxylic acid are heated to 150 to 280°C in the presence of a known esterification catalyst such as tetrabutoxytitanate or dibutyltin oxide, and the generated water is distilled off while reducing the pressure as necessary to obtain a polyester having hydroxyl groups.

[0032] Next, this is reacted with polyisocyanate at 40 to 140° C. to obtain a modified polyester resin (A) having an isocyanate group. Furthermore, this (A) is reacted with amines (B) at 40 to 140° C. to obtain a polyester modified with a urea bond. When reacting with polyisocyanate and when reacting (A) with (B), a solvent can be used as necessary.

[0033] Examples of solvents that can be used include those that are inactive against polyisocyanates, such as aromatic solvents such as toluene and xylene; ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone; esters such as ethyl acetate; amides such as dimethylformamide and dimethylacetamide; and ethers such as tetrahydrofuran.

[0034] When the unmodified polyester (A') is used in combination, this (A') is produced in the same manner as in the case of the polyester having hydroxyl groups, and this is dissolved and mixed in the solution obtained after the reaction of the urea-modified polyester is completed.

[0035] The resin used in this embodiment is preferably a low molecular weight polyester resin. In addition, from the viewpoint of a standard solution for calibrating a blood cell counter, the density of carboxyl groups on the resin surface is preferably 0.001 / Å. 2 More preferably, it is equal to or greater than this.

[0036] In this case, the resin constituting the resin particles preferably has an acid value of 40 mgKOH / g or more, which increases the dispersibility of the resin particles in the standard solution for calibrating a hemocytometer, thereby improving the calibration accuracy and storage stability of the standard solution for calibrating a hemocytometer.

[0037] The acid value of the resin means the content of carboxyl groups in the polyester resin. The acid value of the polyester resin is determined by neutralization titration based on JIS K0070 (1992).

[0038] The dispersed particles of the standard solution for calibrating a hemocytometer can be formed by reacting a dispersion of an isocyanate-modified polyester (A) with an amine (B) in an aqueous medium.

[0039] Examples of a method for stably forming a dispersion of urea-modified polyester or isocyanate-modified polyester (A) in an aqueous medium include a method in which components of dispersed particle raw materials of a standard solution for calibrating a hemocytometer, which comprises urea-modified polyester or isocyanate-modified polyester (A), are added to an aqueous medium and dispersed by shear force.

[0040] The modified polyester (A) may further be mixed with other dispersed particle components of a standard solution for calibrating a blood cell counter (hereinafter also referred to as dispersed particle raw material).

[0041] Examples of the dispersed particle raw material include a colorant, a colorant master batch, a release agent, a charge control agent, and an unmodified polyester (A'). These dispersed particle raw materials may be mixed when forming a dispersion in an aqueous medium, but it is preferable to mix the dispersed particle raw material of the standard solution for calibrating a hemocytometer in advance, and then add the mixture to the aqueous medium to disperse it.

[0042] The dispersing device is not particularly limited, and any commercially available stirrer or dispersing device can be used.

[0043] Examples of such dispersion devices include batch-type dispersers such as Homogenizer (manufactured by IKA Corporation) and TK Auto Homo Mixer (manufactured by Tokushu Kika Kogyo Co., Ltd.); continuous-type dispersers such as Ebara Milder (manufactured by Arihara Manufacturing Co., Ltd.) and TK Pipeline Homo Mixer (manufactured by Tokushu Kika Kogyo Co., Ltd.); and high-pressure dispersers such as Microfluidizer (manufactured by Mizuho Kogyo Co., Ltd.), Nanomizer (manufactured by Nanomizer Co., Ltd.) and APV Gaulin (manufactured by Gaulin Co., Ltd.), among others, which are commercially available by name.

[0044] Of these, from the viewpoint of applying a uniform shear force, APV Gaulin, homogenizer, TK Auto Homo Mixer, Ebara Milder and TK Pipeline Homo Mixer are preferred, and TK Auto Homo Mixer and TK Pipeline Homo Mixer are more preferred.

[0045] The temperature during dispersion is preferably 0 to 150° C., more preferably 5 to 98° C., and particularly preferably 10 to 60° C. When it exceeds 100° C., the temperature is under pressure.

[0046] The standard solution for calibrating a blood cell counter of this embodiment may contain other optional components such as a dispersant, a thickener, a viscosity reducer, etc., as long as the object of the present invention is not impaired.

[0047] The dispersant is preferably used to emulsify and disperse the oil layer in which the dispersed particle components of the standard solution for calibrating a hemocytometer are dispersed in an aqueous medium. As the dispersant, a known surfactant (S) can be used. When the surfactant (S) is used, the amount of the surfactant used is preferably 0.0001 to 50% by weight, more preferably 0.0005 to 0.4% by weight, and even more preferably 0.001 to 0.3% by weight, based on the total weight of (A), (B), and (A').

[0048] As the surfactant (S), an anionic surfactant (S-1), a cationic surfactant (S-2), etc. are used.

[0049] As the anionic surfactant (S-1), a carboxylic acid or a salt thereof, a sulfate ester salt, a salt of a carboxymethyl compound, a sulfonate salt, a phosphate ester salt, or the like can be used.

[0050] As the carboxylic acid or its salt, a saturated or unsaturated fatty acid having 8 to 22 carbon atoms or a salt thereof can be used. Examples of the saturated or unsaturated fatty acid having 8 to 22 carbon atoms include capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, oleic acid, linoleic acid, and ricinoleic acid, as well as mixtures of higher fatty acids obtained by saponifying coconut oil, palm kernel oil, rice bran oil, beef tallow, etc.

[0051] Examples of the salt of a carboxylic acid include a sodium salt, a potassium salt, an amine salt, an ammonium salt, a quaternary ammonium salt, and an alkanolamine salt (for example, a monoethanolamine salt, a diethanolamine salt, a triethanolamine salt, etc.).

[0052] As the sulfate, a higher alcohol sulfate (a sulfate of an aliphatic alcohol having 8 to 18 carbon atoms), a higher alkyl ether sulfate (a sulfate of an ethylene oxide or propylene oxide adduct of an aliphatic alcohol having 8 to 18 carbon atoms), etc. can be used.

[0053] Examples of salts of sulfate esters include sodium salts, potassium salts, amine salts, ammonium salts, quaternary ammonium salts, and alkanolamine salts (for example, monoethanolamine salts, diethanolamine salts, triethanolamine salts, etc.).

[0054] Examples of higher alcohol sulfates include octyl alcohol sulfate, decyl alcohol sulfate, lauryl alcohol sulfate, and stearyl alcohol sulfate.

[0055] Examples of the salt of the carboxymethylation product that can be used include a salt of a carboxymethylation product of an aliphatic alcohol having 8 to 16 carbon atoms, and a salt of a carboxymethylation product of an adduct of 1 to 10 moles of ethylene oxide or propylene oxide with an aliphatic alcohol having 8 to 16 carbon atoms.

[0056] Examples of salts of carboxymethylated aliphatic alcohols include sodium carboxymethylated octyl alcohol, sodium carboxymethylated decyl alcohol, sodium carboxymethylated lauryl alcohol, sodium carboxymethylated dobanol 23, and sodium carboxymethylated tridecanol.

[0057] Examples of the salts of carboxymethylated products of 1-10 mole ethylene oxide adducts of aliphatic alcohols include carboxymethylated sodium salt of octyl alcohol ethylene oxide 3 mole adduct, carboxymethylated sodium salt of lauryl alcohol ethylene oxide 4 mole adduct, carboxymethylated sodium salt of dobanol 23 ethylene oxide 3 mole adduct, and carboxymethylated sodium salt of tridecanol ethylene oxide 5 mole adduct.

[0058] Examples of sulfonates that can be used include alkylbenzenesulfonates, alkylnaphthalenesulfonates, sulfosuccinic acid diester salts, α-olefinsulfonates, Igepon T type, and sulfonates of other aromatic ring-containing compounds.

[0059] Examples of alkylbenzenesulfonates include sodium dodecylbenzenesulfonate.

[0060] Examples of alkylnaphthalenesulfonates include sodium dodecylnaphthalenesulfonate.

[0061] The sulfosuccinic acid diester salts include, for example, sodium salt of di-2-ethylhexyl sulfosuccinate.

[0062] Examples of sulfonates of aromatic ring-containing compounds include mono- or disulfonates of alkylated diphenyl ethers, and styrenated phenol sulfonates.

[0063] As the phosphate salt, a higher alcohol phosphate salt, a higher alcohol ethylene oxide adduct phosphate salt, etc. can be used.

[0064] Examples of higher alcohol phosphate ester salts include lauryl alcohol phosphate monoester disodium salt and lauryl alcohol phosphate diester sodium salt.

[0065] Examples of the higher alcohol ethylene oxide adduct phosphate ester salt include oleyl alcohol ethylene oxide 5 mole adduct phosphate monoester disodium salt.

[0066] These anionic surfactants (S-1) may be used alone or in combination of two or more.

[0067] As the cationic surfactant (S-2), a quaternary ammonium salt surfactant, etc. can be used. The quaternary ammonium salt surfactant can be obtained by reacting a tertiary amine having 3 to 40 carbon atoms with a quaternizing agent (for example, an alkylating agent such as methyl chloride, methyl bromide, ethyl chloride, benzyl chloride, and dimethyl sulfate, or ethylene oxide, etc.).

[0068] Examples of quaternary ammonium salt surfactants include lauryl trimethyl ammonium chloride, didecyl dimethyl ammonium chloride, lauryl dimethyl benzyl ammonium chloride (benzalkonium chloride), polyoxyethylene trimethyl ammonium chloride, and stearamidoethyl diethyl methyl ammonium methosulfate.

[0069] These anionic surfactants (S-1) may be used alone or in combination of two or more.

[0070] As the dispersant, fine particles other than resin particles are preferably used to stabilize the dispersed particle base particles of the standard solution for calibrating a hemocytometer formed in an aqueous medium. Such fine particles are preferably added so that the coverage of the surface of the dispersed particle base particles of the standard solution for calibrating a hemocytometer is in the range of 10 to 90%.

[0071] Examples of microparticles include polymethyl methacrylate microparticles of 1 μm and 3 μm, polystyrene microparticles of 0.5 μm and 2 μm, poly(styrene-acrylonitrile) microparticles of 1 μm, and organic microparticles with trade names such as PB-200H (manufactured by Kao Corporation), SGP (manufactured by Sokensha), Technopolymer SB (manufactured by Sekisui Chemical Co., Ltd.), SGP-3G (manufactured by Sokensha), and Micropearl (manufactured by Sekisui Fine Chemical Co., Ltd.).

[0072] Furthermore, as the fine particles, for example, inorganic fine particles such as tricalcium phosphate, calcium carbonate, titanium oxide, colloidal silica, and hydroxyapatite can also be used.

[0073] A polymeric protective colloid may be used as a dispersant in combination with these fine particles to stabilize the dispersion.

[0074] Examples of the polymer protective colloid include, but are not limited to, acids such as acrylic acid, methacrylic acid, α-cyanoacrylic acid, α-cyanomethacrylic acid, itaconic acid, crotonic acid, fumaric acid, maleic acid, and maleic anhydride, and (meth)acrylic monomers containing a hydroxyl group; β-hydroxyethyl acrylate, β-hydroxyethyl methacrylate, β-hydroxypropyl acrylate, β-hydroxypropyl methacrylate, γ-hydroxypropyl acrylate, γ-hydroxypropyl methacrylate, 3-chloro-2-hydroxypropyl acrylate, 3-chloro-2-hydroxypropyl methacrylate, diethylene glycol monoacrylate, diethylene glycol monomethacrylate, glycerin monoacrylate, glycerin monomethacrylate, N-methylol acrylamide, N-methylol methacrylamide, and the like; vinyl alcohol or ethers with vinyl alcohol; vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether. or esters of vinyl alcohol and a compound containing a carboxyl group; vinyl acetate, vinyl propionate, vinyl butyrate, etc.; acrylamide, methacrylamide, diacetone acrylamide, or methylol compounds thereof; acid chlorides such as acrylic acid chloride, methacrylic acid chloride, etc.; nitrogen-containing compounds such as vinylpyridine, vinylpyrrolidone, vinylimidazole, ethyleneimine, etc., or homopolymers or copolymers of compounds having a heterocycle thereof; polyoxyethylene-based compounds such as polyoxyethylene, polyoxypropylene, polyoxyethylene alkylamines, polyoxypropylene alkylamines, polyoxyethylene alkylamides, polyoxypropylene alkylamides, polyoxyethylene nonylphenyl ether, polyoxyethylene lauryl phenyl ether, polyoxyethylene stearyl phenyl ester, polyoxyethylene nonyl phenyl ester, etc.; celluloses such as methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, etc.

[0075] The dispersed particles of the standard solution for hemocytometer calibration of this embodiment are produced by a production method including a step of deforming the dispersed particles of the standard solution for hemocytometer calibration by applying a shear force while removing the organic solvent from the emulsion dispersion liquid containing the dispersed particles of the standard solution for hemocytometer calibration obtained as described above. In the step of deforming the dispersed particles of the standard solution for hemocytometer calibration, the average circularity value of the dispersed particles in the standard solution for hemocytometer calibration is adjusted to 0.99 or less, preferably 0.92 to 0.96.

[0076] The average circularity of the dispersed particles in the standard solution for calibrating a hemocytometer is measured using a flow type particle image analyzer.

[0077] Specifically, 100-150 mL of water from which solid impurities have been removed is placed in a specified container, 0.1-0.5 mL of a surfactant is added as a dispersant, and then about 0.1-9.5 g of the measurement sample is added. The suspension in which the sample is dispersed is subjected to a dispersion treatment for about 1-3 minutes using an ultrasonic disperser, and the dispersion concentration is adjusted to 3,000-10,000 particles / μL, and the shape and distribution of the dispersed particles in the standard solution for calibrating a hemocytometer are measured.

[0078] The thickener is preferably used to increase the viscosity of the emulsion dispersion and to deform the resin particles (dispersed particles) contained in the standard solution for calibrating a hemocytometer.

[0079] Examples of the thickener include water-soluble thickeners such as polyvinyl alcohol, hydroxyethyl cellulose, hydroxypropyl cellulose, polyacrylates (alkali metal salts, organic amine salts, quaternary ammonium salts, etc.) (weight average molecular weight 3000 to 3,000,000), carboxymethyl cellulose, polyethylene glycol (weight average molecular weight 2000 to 200,000), and guar gum.

[0080] These thickeners may be used alone or in combination of two or more kinds.

[0081] In the case of the standard solution for calibrating a blood cell counter of this embodiment, any device that is generally commercially available as a stirrer or disperser can be used as a device for applying shear force to the emulsion dispersion thickened by such a thickener, without any particular limitation.

[0082] Preferred specific examples include a stirrer having 1 to 10 stages of paddle-type stirring blades, a helical ribbon type stirrer, a Max Blend type stirrer, etc. Among these, the helical ribbon type stirrer and the Max Blend type stirrer are preferred from the viewpoint of applying a uniform shear force.

[0083] The shear force varies depending on the viscosity of the emulsion dispersion, the time for applying the shear force, and the temperature at that time, and can be appropriately selected. From the viewpoint of ease of deformation of the resin particles and ease of particle size control, for example, in the device for applying the shear force as exemplified above, the shear force is preferably applied at a rotation speed of 70 to 50,000 rpm, more preferably 100 to 20,000 rpm, and further preferably 500 to 10,000 rpm.

[0084] The conditions for the deformation process are preferably as follows: In the deformation process, the concentration of the organic solvent in the emulsion dispersion is preferably 2 to 10% by weight, more preferably 2.5 to 9% by weight, and further preferably 3 to 8% by weight.

[0085] When the concentration of the organic solvent is 2% by weight or more, the dispersed particles of the standard solution for calibrating a blood cell counter are easily deformed, and the process of deforming can be shortened. On the other hand, when the concentration of the organic solvent is 10% by weight or less, the deformed particles are less likely to return to their original shape, and when the organic solvent is finally removed to form dispersed particles of the standard solution for calibrating a blood cell counter, the desired shape can be easily obtained.

[0086] The concentration of the organic solvent at the start of the deforming step is preferably 3 to 10% by weight. If the starting concentration is 3% by weight or more, deforming occurs easily, and if it is 10% by weight or less, the generation of fine powder is reduced. The concentration of the organic solvent is adjusted to a desired concentration by removing the solvent. The concentration of the organic solvent can be measured using gas chromatography under the following conditions.

[0087] [Concentration measurement of organic solvents] Equipment: Gas chromatograph (SIMAZU GC-14A, manufactured by Shimadzu Corporation) Column: PEG 20M 20% Chromasorb W MESH 60-80 Column temperature: 100℃ Injection temperature: 180℃ Nitrogen gas flow rate: 40ml / min Sample solution: 5% dimethylformamide solution Solution injection volume: 1μL Detector: FID30

[0088] A calibration curve was prepared using n-hexane as a standard substance to determine the organic solvent concentration. The method for desolvation during the heteromorphization step is not particularly limited as long as it is a method that can remove the solvent, such as atmospheric desolvation by blowing air or nitrogen into the liquid phase, or reduced pressure desolvation, but reduced pressure desolvation is preferred because it can be performed at a relatively low temperature.

[0089] The degree of reduced pressure is preferably 1 to 90 kPa, more preferably 5 to 50 kPa. As the solvent is removed, the viscosity of the emulsion dispersion increases, but in order to favorably perform the deformation, it is preferable to add the above-mentioned water-soluble thickener to the emulsion dispersion to adjust the viscosity.

[0090] The viscosity of the mixture of the emulsified dispersion and the thickener is preferably in the range of 5,000 to 50,000 mPa·s, more preferably 5,500 to 40,000 mPa·s, and further preferably 6,000 to 35,000 mPa·s.

[0091] By having the viscosity in this range, it is possible to shorten the time required to deform the shape of the dispersed particles in the standard solution for calibrating a hemocytometer by applying a shear force, and it is also possible to obtain a dispersion that is less likely to return to a spherical shape after deformation and has a stable shape after deformation. The viscosity of the mixture is measured using a B-type viscometer after 30 minutes in a thermostatic bath at 25°C.

[0092] After the end of the modification step, the organic solvent may be further removed from the emulsion dispersion, if necessary. The method for removing the solvent is not particularly limited.

[0093] As a method for removing the solvent, for example, there is a method of blowing in a gas such as air or nitrogen as a carrier at normal pressure to remove the organic solvent. There is also a method of removing the organic solvent under reduced pressure using a vacuum pump or the like. Still further, there is a method of pouring the emulsified dispersion liquid after the deformation process into a liquid in which the dispersed particle components of the standard solution for calibrating a hemocytometer are insoluble and the solvent is soluble, such as water, lower alcohols such as methanol and ethanol, and mixtures thereof, to extract and remove the organic solvent.

[0094] After the deformation step, the viscosity of the emulsion dispersion may be reduced using a viscosity reducer, if necessary.

[0095] Examples of viscosity reducing agents include enzymes such as α-glycanase (amylase, dextrase, pullulase, etc.) and β-glycanase (cellulase, β-1,3-glucanase, chitinase, etc.) These viscosity reducing agents may be used alone or in combination of two or more.

[0096] The amount of the viscosity reducer added varies depending on the type of thickener, but from the viewpoints of productivity (thickening time) and production costs, it is preferably 1 wt % or less, more preferably 0.000001 to 0.1 wt %, and even more preferably 0.00001 to 0.01% based on the weight of the emulsion dispersion.

[0097] The viscosity of the reduced emulsion dispersion is preferably 200 mPa s or less, more preferably 100 mPa s or less, and even more preferably 40 mPa s or less. When the viscosity of the emulsion dispersion is in this range, it is easy to handle in the process up to obtaining dispersed particles of the standard solution for calibrating a hemocytometer, and is easy to wash in the washing process described below that is performed as needed.

[0098] The resin particles contained in the standard solution for calibrating a blood cell counter of this embodiment preferably have a particle size variation coefficient [(standard deviation of particle size / average particle size)×100(%)] of 10% or less, and are usually provided with dispersion stability so that they are mixed into an aqueous medium such as water or an aqueous electrolyte solution to form a single dispersion state. Examples of electrolytes used in this aqueous electrolyte solution include sodium chloride and potassium chloride.

[0099] The dispersion stability of fine particles in a liquid phase depends on the acidic polar groups (eg, carboxyl groups) present on the surface of the fine particles, and the more acidic polar groups present on the surface of the fine particles, the better the dispersion stability.

[0100] The polymer particles to which dispersion stability has been imparted are not particularly limited, and examples of such polymer particles that are preferably used include copolymers of hydrophilic monomers and polymer particles having dissociable or hydrophilic groups on the surface.

[0101] Examples of hydrophilic monomers constituting the copolymer of hydrophilic monomers include ionic monomers such as acrylic acid, methacrylic acid, acrylamide-N-propanesulfonic acid, and sodium styrenesulfonate, each of which has a dissociable group such as a carboxyl group or a sulfonic acid group, or a hydrophilic group such as a hydroxyl group or an amide group, as well as hydroxyethyl (meth)acrylate, (meth)acrylamide, and N-vinylpyrrolidone.

[0102] As the polymer particles having dissociable groups or hydrophilic groups on the surface, for example, polymer particles having dissociable groups or hydrophilic groups on the surface thereof introduced by an emulsifier used as necessary during emulsion polymerization are preferred.

[0103] The average particle size of standard particles is preferably 7 to 8 μm for blood cells, and 5.5 × 10 depending on the type of blood cell counter. 5 The concentration is adjusted to ~2.5×10~7 cells / ml. EXAMPLES

[0104] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples. In the following, "parts" and "%" are by mass unless otherwise specified. In addition, various tests and evaluations were performed according to the following methods.

[0105] <Average circularity> Measurements were performed using a flow particle image analyzer (FPIA-2100, manufactured by Sysmex Corporation). 100-150 mL of water from which impurities and solids had been removed was placed in a designated container, 0.1-0.5 mL of a surfactant was added as a dispersant, and then approximately 0.1-9.5 g of the measurement sample was added. The suspension in which the sample was dispersed was subjected to a dispersion treatment for approximately 1-3 minutes using an ultrasonic disperser, and the dispersion concentration was adjusted to 3,000-10,000 particles / μL, and the shape and distribution of the dispersed particles in the standard solution for calibrating hemocytometers were measured.

[0106] <Volume average particle size> The volume average particle size was measured by dynamic light scattering using a zeta potential / particle size measurement system (ELSZ-1000, manufactured by Otsuka Electronics Co., Ltd.). First, 0.2 g of a dispersion of resin particles (standard solution for calibrating a hemocytometer) was taken, then ion-exchanged water was added to dilute it 100 times, and a part of the obtained solution was placed in a quartz cell and set in a sample holder. Then, measurements were performed under the conditions of temperature: 25°C, dust cut (number of times: 5, Upper: 5, Lower: 100), and cumulative number: 70, to obtain the volume average particle size of the solid content in the standard solution for calibrating a hemocytometer.

[0107] <Coefficient of variation of particle size> The particle size distribution of the dispersed particles (resin particles) was measured using a laser diffraction / scattering type particle size distribution analyzer (LA-950, manufactured by Horiba, Ltd.), and the particle size variation coefficient was calculated from the average particle size obtained by the measurement and the standard deviation of the particles according to the formula: [(standard deviation of particle size / average particle size) × 100 (%)].

[0108] <Aspect ratio> 1,000 particles were randomly selected from the electron microscope photograph, and the ratio of their major axis to their minor axis was calculated as the average value.

[0109] <Carboxyl group density> The acid value of the raw material of the resin particles (low molecular weight polyester resin) was measured in accordance with the provisions of JIS K0070 (1992), the content of carboxyl groups in the low molecular weight polyester resin was calculated from the obtained acid value, and the density of carboxyl groups on the surface of the resin particles was calculated from the content of carboxyl groups.

[0110] <Synthesis of low molecular weight polyester> [Low molecular weight polyester 1] In a reaction vessel equipped with a cooling tube, a stirrer and a nitrogen inlet tube, 562 parts of bisphenol A ethylene oxide 2 mole adduct, 75 parts of bisphenol A propylene oxide 2 mole adduct, 87 parts of bisphenol A propylene oxide 3 mole adduct, 143 parts of terephthalic acid, 126 parts of adipic acid and 2 parts of dibutyltin oxide were placed and reacted at normal pressure and 230°C for 8 hours, and then reacted at a reduced pressure of 10 to 15 mmHg for 5 hours. Then, 69 parts of trimellitic anhydride were placed in the reaction vessel and reacted at 180°C and atmospheric pressure for 2 hours to obtain "low molecular weight polyester 1". The acid value of "low molecular weight polyester 1" was 40 mgKOH / g.

[0111] [Low molecular weight polyester 2] In a reaction vessel equipped with a cooling tube, a stirrer and a nitrogen inlet tube, 362 parts of bisphenol A ethylene oxide 2 mole adduct, 75 parts of bisphenol A propylene oxide 2 mole adduct, 83 parts of bisphenol A propylene oxide 2 mole adduct, 143 parts of terephthalic acid, 126 parts of adipic acid and 2 parts of dibutyltin oxide were placed and reacted at normal pressure and 230°C for 8 hours, and then reacted at a reduced pressure of 10 to 15 mmHg for 5 hours. Then, 69 parts of trimellitic anhydride were placed in the reaction vessel and reacted at 180°C and normal pressure for 2 hours to obtain "low molecular weight polyester 2". The acid value of "low molecular weight polyester 2" was 10 mgKOH / g.

[0112] [Low molecular weight polyester 3] In a reaction vessel equipped with a cooling tube, a stirrer and a nitrogen inlet tube, 255 parts of bisphenol A ethylene oxide 2 mole adduct, 480 parts of bisphenol A propylene oxide 2 mole adduct, 223 parts of terephthalic acid, 49 parts of adipic acid and 2 parts of dibutyltin oxide were placed and reacted at normal pressure and 230°C for 8 hours, and then reacted at a reduced pressure of 10-15 mmHg for 5 hours. After that, 1 part of trimellitic anhydride was placed in the reaction vessel and reacted at 180°C and normal pressure for 2 hours to obtain "low molecular weight polyester 3". The acid value of "low molecular weight polyester 3" was 0.1 mgKOH / g.

[0113] <Preparation of oil-based dispersion> [Oil-based dispersion 1] 155 parts of "Low molecular weight polyester 1" and 80 parts of ethyl acetate were placed in a beaker and dissolved by stirring. 1.2 parts of isophorone diamine was added to this dispersion, and the mixture was stirred at 2,000 rpm for 3 minutes using a disperser to obtain "Oil-based dispersion 1."

[0114] [Oil-based dispersion 2] 155 parts of "Low molecular weight polyester 2" and 80 parts of ethyl acetate were placed in a beaker and dissolved by stirring. 1.2 parts of isophorone diamine was added to this dispersion, and the mixture was stirred at 2,000 rpm for 3 minutes using a disperser to obtain "Oil-based dispersion 2."

[0115] [Oil-based dispersion 3] 155 parts of "Low molecular weight polyester 3" and 80 parts of ethyl acetate were placed in a beaker and dissolved by stirring. 1.2 parts of isophorone diamine was added to this dispersion, and the mixture was stirred at 2,000 rpm for 3 minutes using a disperser to obtain "Oil-based dispersion 3."

[0116] [Oil-based dispersion 4] 155 parts of "Low molecular weight polyester 1" and 80 parts of ethyl acetate were placed in a beaker and dissolved by stirring. 1.7 parts of isophorone diamine was added to this dispersion, and the mixture was stirred at 2,000 rpm for 3 minutes using a disperser to obtain "Oil-based dispersion 4."

[0117] [Oil-based dispersion 5] 155 parts of "Low molecular weight polyester 2" and 80 parts of ethyl acetate were placed in a beaker and dissolved by stirring. 1.7 parts of isophorone diamine was added to this dispersion, and the mixture was stirred at 2,000 rpm for 3 minutes using a disperser to obtain "Oil-based dispersion 5."

[0118] [Oil-based dispersion 6] 155 parts of "Low molecular weight polyester 2" and 80 parts of ethyl acetate were placed in a beaker and dissolved by stirring. 1.5 parts of isophorone diamine was added to this dispersion, and the mixture was stirred at 2,000 rpm for 3 minutes using a disperser to obtain "Oil-based dispersion 6."

[0119] [Oil-based dispersion 7] 155 parts of "Low molecular weight polyester 2" and 80 parts of ethyl acetate were placed in a beaker and dissolved by stirring. 1.7 parts of isophorone diamine was added to this dispersion, and the mixture was stirred at 2,000 rpm for 3 minutes using a disperser to obtain "Oil-based dispersion 7."

[0120] [Oil-based dispersion 8] 155 parts of "Low molecular weight polyester 2" and 80 parts of ethyl acetate were placed in a beaker and dissolved by stirring. 2.0 parts of isophorone diamine was added to this dispersion, and the mixture was stirred at 2,000 rpm for 3 minutes using a disperser to obtain "Oil-based dispersion 8."

[0121] <Preparation of aqueous dispersion medium> [Aqueous dispersion medium 1] 945 parts of pure water, 40 parts of a 20% aqueous dispersion of a styrene-methacrylic acid-butyl acrylate copolymer, 160 parts of a 50% aqueous solution of sodium dodecyl diphenyl ether disulfonate (Eleminol MON-7, manufactured by Sanyo Chemical Industries), and 90 parts of ethyl acetate were placed in a container and mixed at 1,000 rpm for 3 minutes using Robomics to obtain "aqueous dispersion medium liquid 1."

[0122] <Preparation of standard solution for hemocytometer calibration> [Example 1] 37 parts of "oil-based dispersion liquid 1" and 63 parts of "aqueous dispersion medium liquid 1" were placed in a beaker and mixed with a TK homomixer at 12,000 rpm for 5 minutes to obtain "dispersion slurry 1." Next, the organic solvent was removed from "dispersion slurry 1" at 25°C until the residual solvent concentration per 100 parts of resin solids was 15%, to obtain "dispersion slurry 2."

[0123] Next, "Dispersion Slurry 2" and a thickener were placed in a stainless steel container so that the thickener was 3% relative to the resin solid content, and mixed for 30 minutes at 200 rpm using a helical ribbon, after which 100 parts of pure water were added to the container to obtain "Dispersion Slurry 3." The organic solvent was removed from "Dispersion Slurry 3" at 25°C until the residual solvent concentration relative to 100 parts of resin solid content was 1% or less, and then the mixture was washed to obtain "Hemocytometer Calibration Standard Solution 1."

[0124] The volume average particle size of the particles dispersed in "Hemocytometer Calibration Standard Solution 1" was 7.5 μm, the coefficient of variation of the particle size was 2.7%, the circularity was 0.970, and the aspect ratio was 1.5. The carboxyl group density on the particle surface, as determined by acid-base titration, was 12 / Å. 2 The results are shown in Table 1.

[0125] [Example 2] 37 parts of "Oil-based Dispersion Liquid 2" and 63 parts of "Aqueous Dispersion Medium Liquid 1" were placed in a beaker and mixed with a TK Homomixer at 12,000 rpm for 5 minutes to obtain "Dispersion Slurry 2." Next, the organic solvent was removed from "Dispersion Slurry 2" at 25°C until the residual solvent concentration per 100 parts of resin solids was 10%, to obtain "Dispersion Slurry 3."

[0126] Next, "Dispersion Slurry 3" and a thickener were placed in a stainless steel container so that the thickener was 3% relative to the resin solid content, and mixed for 30 minutes at 200 rpm using a helical ribbon, after which 100 parts of pure water were added to the container to obtain "Dispersion Slurry 4." The organic solvent was removed from "Dispersion Slurry 4" at 25°C until the residual solvent concentration relative to 100 parts of resin solid content was 1% or less, and then the mixture was washed to obtain "Hemocytometer Calibration Standard Solution 2."

[0127] The volume average particle size of the particles dispersed in "Hemocytometer Calibration Standard Solution 2" was 7.8 μm, the coefficient of variation of the particle size was 5.3%, the circularity was 0.985, and the aspect ratio was 1.7. The carboxyl group density on the particle surface, as determined by acid-base titration, was 0.340 particles / Å. 2 The results are shown in Table 1.

[0128] [Example 3] 37 parts of "Oil-based Dispersion Liquid 2" and 63 parts of "Aqueous Dispersion Medium Liquid 1" were placed in a beaker and mixed with a TK Homomixer at 12,000 rpm for 5 minutes to obtain "Dispersion Slurry 5." Next, the organic solvent was removed from "Dispersion Slurry 5" at 25°C until the residual solvent concentration per 100 parts of resin solids was 30%, to obtain "Dispersion Slurry 6."

[0129] Next, "Dispersion Slurry 6" and a thickener were placed in a stainless steel container so that the thickener was 5% relative to the resin solid content, and mixed for 30 minutes at 200 rpm using a helical ribbon, after which 100 parts of pure water were added to the container to obtain "Dispersion Slurry 7." The organic solvent was removed from "Dispersion Slurry 7" at 25°C until the residual solvent concentration relative to 100 parts of resin solid content was 1% or less, and then the mixture was washed to obtain "Hemocytometer Calibration Standard Solution 3."

[0130] The volume average particle size of the particles dispersed in "Hemocytometer Calibration Standard Solution 3" was 7.2 μm, the coefficient of variation of the particle size was 6.5%, the circularity was 0.950, and the aspect ratio was 4.3. The carboxyl group density on the particle surface, as determined by acid-base titration, was 0.160 particles / Å. 2 The results are shown in Table 1.

[0131] [Example 4] 37 parts of "Oil-based Dispersion Liquid 2" and 63 parts of "Aqueous Dispersion Medium Liquid 1" were placed in a beaker and mixed with a TK Homomixer at 12,000 rpm for 5 minutes to obtain "Dispersion Slurry 5." Next, the organic solvent was removed from "Dispersion Slurry 5" at 25°C until the residual solvent concentration per 100 parts of resin solids was 15%, to obtain "Dispersion Slurry 6."

[0132] Next, "Dispersion Slurry 6" and a thickener were placed in a stainless steel container so that the thickener was 3% relative to the resin solid content, and mixed for 30 minutes at 200 rpm using a helical ribbon, after which 100 parts of pure water were added to the container to obtain "Dispersion Slurry 8." The organic solvent was removed from "Dispersion Slurry 8" at 25°C until the residual solvent concentration relative to 100 parts of resin solid content was 1% or less, and then the mixture was washed to obtain "Hemocytometer Calibration Standard Solution 4."

[0133] The volume average particle size of the particles dispersed in "Hemocytometer Calibration Standard Solution 4" was 7.3 μm, the coefficient of variation of the particle size was 10.3%, the circularity was 0.973, and the aspect ratio was 4.3. The carboxyl group density on the particle surface, as determined by acid-base titration, was 0.260 particles / Å. 2 The results are shown in Table 1.

[0134] [Example 5] 37 parts of "Oil-based Dispersion 3" and 63 parts of "Aqueous Dispersion Medium 1" were placed in a beaker and mixed with a TK homomixer at 12,000 rpm for 5 minutes to obtain "Dispersion Slurry 9." Next, the organic solvent was removed from "Dispersion Slurry 9" at 25°C until the residual solvent concentration per 100 parts of resin solids was 15%, to obtain "Dispersion Slurry 10."

[0135] Next, "Dispersion Slurry 10" and a thickener were placed in a stainless steel container so that the thickener was 3% relative to the resin solid content, and mixed for 30 minutes at 200 rpm using a helical ribbon, after which 100 parts of pure water were added to the container to obtain "Dispersion Slurry 11." The organic solvent was removed from "Dispersion Slurry 11" at 25°C until the residual solvent concentration relative to 100 parts of resin solid content was 1% or less, and then the mixture was washed to obtain "Hemocytometer Calibration Standard Solution 5."

[0136] The volume average particle size of the particles dispersed in "Hemocytometer Calibration Standard Solution 5" was 7.4 μm, the coefficient of variation of the particle size was 6.8%, the circularity was 0.965, and the aspect ratio was 3.2. The carboxyl group density on the particle surface, as determined by acid-base titration, was 0.001 particles / Å. 2 The results are shown in Table 1.

[0137] [Example 6] 37 parts of "Oil-based Dispersion Liquid 4" and 63 parts of "Aqueous Dispersion Medium Liquid 1" were placed in a beaker and mixed with a TK Homomixer at 12,000 rpm for 5 minutes to obtain "Dispersion Slurry 12." Next, the organic solvent was removed from "Dispersion Slurry 12" at 25°C until the residual solvent concentration per 100 parts of resin solids was 15%, to obtain "Dispersion Slurry 13."

[0138] Next, "Dispersion Slurry 13" and a thickener were placed in a stainless steel container so that the thickener was 3% relative to the resin solid content, and mixed for 30 minutes at 200 rpm using a helical ribbon, after which 100 parts of pure water were added to the container to obtain "Dispersion Slurry 14." The organic solvent was removed from "Dispersion Slurry 14" at 25°C until the residual solvent concentration relative to 100 parts of resin solid content was 1% or less, and then the mixture was washed to obtain "Hemocytometer Calibration Standard Solution 6."

[0139] The volume average particle size of the particles dispersed in "Hemocytometer Calibration Standard Solution 6" was 3.4 μm, the coefficient of variation of the particle size was 2.7%, the circularity was 0.970, and the aspect ratio was 1.5. The carboxyl group density on the particle surface, as determined by acid-base titration, was 12,000 particles / Å. 2 The results are shown in Table 1.

[0140] [Example 7] 37 parts of "Oil-based Dispersion Liquid 4" and 63 parts of "Aqueous Dispersion Medium Liquid 1" were placed in a beaker and mixed with a TK Homomixer at 12,000 rpm for 5 minutes to obtain "Dispersion Slurry 15." Next, the organic solvent was removed from "Dispersion Slurry 15" at 25°C until the residual solvent concentration per 100 parts of resin solids was 10%, to obtain "Dispersion Slurry 16."

[0141] Next, "Dispersion Slurry 16" and a thickener were placed in a stainless steel container so that the thickener was 3% relative to the resin solid content, and mixed for 30 minutes at 200 rpm using a helical ribbon, after which 100 parts of pure water were added to the container to obtain "Dispersion Slurry 17." The organic solvent was removed from "Dispersion Slurry 17" at 25°C until the residual solvent concentration relative to 100 parts of resin solid content was 1% or less, and then the mixture was washed to obtain "Hemocytometer Calibration Standard Solution 7."

[0142] The volume average particle size of the particles dispersed in "Hemocytometer Calibration Standard Solution 7" was 3.1 μm, the coefficient of variation of the particle size was 5.3%, the circularity was 0.985, and the aspect ratio was 1.7. The carboxyl group density on the particle surface, as determined by acid-base titration, was 0.340 particles / Å. 2 The results are shown in Table 1.

[0143] [Example 8] 37 parts of "Oil-based Dispersion Liquid 6" and 63 parts of "Aqueous Dispersion Medium Liquid 1" were placed in a beaker and mixed with a TK homomixer at 12,000 rpm for 5 minutes to obtain "Dispersion Slurry 18." Next, the organic solvent was removed from "Dispersion Slurry 18" at 25°C until the residual solvent concentration per 100 parts of resin solids was 30%, to obtain "Dispersion Slurry 19."

[0144] Next, "Dispersion Slurry 19" and a thickener were placed in a stainless steel container so that the amount of the thickener was 5% relative to the resin solid content, and mixed for 30 minutes at 200 rpm using a helical ribbon, after which 100 parts of pure water were added to the container to obtain "Dispersion Slurry 20." The organic solvent was removed from "Dispersion Slurry 20" at 25°C until the residual solvent concentration relative to 100 parts of resin solid content was 1% or less, and then the mixture was washed to obtain "Hemocytometer Calibration Standard Solution 8."

[0145] The volume average particle size of the particles dispersed in "Hemocytometer Calibration Standard Solution 8" was 4.3 μm, the coefficient of variation of the particle size was 6.5%, the circularity was 0.950, and the aspect ratio was 4.3. The carboxyl group density on the particle surface, as determined by acid-base titration, was 0.160 particles / Å. 2 The results are shown in Table 1.

[0146] [Example 9] 37 parts of "Oil-based Dispersion Liquid 6" and 63 parts of "Aqueous Dispersion Medium Liquid 1" were placed in a beaker and mixed with a TK Homomixer at 12,000 rpm for 5 minutes to obtain "Dispersion Slurry 18." Next, the organic solvent was removed from "Dispersion Slurry 18" at 25°C until the residual solvent concentration per 100 parts of resin solids was 15%, to obtain "Dispersion Slurry 19."

[0147] Next, "Dispersion Slurry 19" and a thickener were placed in a stainless steel container so that the thickener was 3% relative to the resin solid content, and mixed for 30 minutes at 200 rpm using a helical ribbon, after which 100 parts of pure water were added to the container to obtain "Dispersion Slurry 20." The organic solvent was removed from "Dispersion Slurry 20" at 25°C until the residual solvent concentration relative to 100 parts of resin solid content was 1% or less, and then the mixture was washed to obtain "Hemocytometer Calibration Standard Solution 9."

[0148] The volume average particle size of the particles dispersed in "Hemocytometer Calibration Standard Solution 9" was 4.5 μm, the coefficient of variation of the particle size was 10.3%, the circularity was 0.973, and the aspect ratio was 4.3. The carboxyl group density on the particle surface, as determined by acid-base titration, was 0.260 particles / Å. 2 The results are shown in Table 1.

[0149] [Example 10] 37 parts of "Oil-based Dispersion Liquid 7" and 63 parts of "Aqueous Dispersion Medium Liquid 1" were placed in a beaker and mixed with a TK homomixer at 12,000 rpm for 5 minutes to obtain "Dispersion Slurry 21." Next, the organic solvent was removed from "Dispersion Slurry 21" at 25°C until the residual solvent concentration per 100 parts of resin solids was 15%, to obtain "Dispersion Slurry 22."

[0150] Next, "Dispersion Slurry 22" and a thickener were placed in a stainless steel container so that the thickener was 3% relative to the resin solid content, and mixed for 30 minutes at 200 rpm using a helical ribbon, after which 100 parts of pure water were added to the container to obtain "Dispersion Slurry 23." The organic solvent was removed from "Dispersion Slurry 23" at 25°C until the residual solvent concentration relative to 100 parts of resin solid content was 1% or less, and then the mixture was washed to obtain "Hemocytometer Calibration Standard Solution 10."

[0151] The volume average particle size of the particles dispersed in "Hemocytometer Calibration Standard Solution 10" was 3.8 μm, the coefficient of variation of the particle size was 6.8%, the circularity was 0.965, and the aspect ratio was 3.2. The carboxyl group density on the particle surface, as determined by acid-base titration, was 0.001 particles / Å. 2 The results are shown in Table 1.

[0152] [Comparative Example 1] 33 parts of "Oil-based Dispersion Liquid 8" and 67 parts of "Aqueous Dispersion Medium Liquid 1" were placed in a beaker and mixed with a TK Homomixer at 12,000 rpm for 5 minutes to obtain "Dispersion Slurry 24." Next, the organic solvent was removed from "Dispersion Slurry 24" at 25°C until the residual solvent concentration per 100 parts of resin solids was 10%, to obtain "Dispersion Slurry 25."

[0153] Next, "Dispersion Slurry 25" and a thickener were placed in a stainless steel container so that the thickener was 3% relative to the resin solid content, and mixed for 30 minutes at 200 rpm using a helical ribbon, after which 100 parts of pure water were added to the container to obtain "Dispersion Slurry 26." The organic solvent was removed from "Dispersion Slurry 26" at 25°C until the residual solvent concentration relative to 100 parts of resin solid content was 1% or less, and then the mixture was washed to obtain "Hemocytometer Calibration Standard Solution 11."

[0154] The volume average particle size of the particles dispersed in "Hemocytometer Calibration Standard Solution 11" was 1.5 μm, the coefficient of variation of the particle size was 5.2%, the circularity was 0.985, and the aspect ratio was 1.5. The carboxyl group density on the particle surface, as determined by acid-base titration, was 0.001 particles / Å. 2 The measurement results are shown in Table 1.

[0155] [Comparative Example 2] 37 parts of "Oil-based Dispersion Liquid 2" and 63 parts of "Aqueous Dispersion Medium Liquid 1" were placed in a beaker and mixed with a TK Homomixer at 12,000 rpm for 5 minutes to obtain "Dispersion Slurry 27." Next, the organic solvent was removed from "Dispersion Slurry 27" at 25°C until the residual solvent concentration per 100 parts of resin solids was 5%, to obtain "Dispersion Slurry 28."

[0156] Next, "Dispersion Slurry 28" was placed in a stainless steel container and mixed at 200 rpm for 30 minutes using a helical ribbon, after which 100 parts of pure water was added to the container to obtain "Dispersion Slurry 29." The organic solvent was removed from "Dispersion Slurry 29" at 25°C until the residual solvent concentration per 100 parts of resin solids was 1% or less, and then the mixture was washed to obtain "Hemocytometer Calibration Standard Solution 12."

[0157] The volume average particle size of the particles dispersed in "Hemocytometer Calibration Standard Solution 12" was 7.4 μm, the coefficient of variation of the particle size was 5.6%, the circularity was 0.995, and the aspect ratio was 1.0. The carboxyl group density on the particle surface, as determined by acid-base titration, was 0.13 particles / Å. 2 The results are shown in Table 1.

[0158] [Table 1]

[0159] The prepared standard solutions 1 to 12 for calibrating a blood cell counter (Examples 1 to 10, and Comparative Examples 1 and 2) were evaluated for the calibration accuracy of the device using a blood cell counter based on the electrical resistance detection method, and the storage stability of the standard solutions for calibrating a blood cell counter over time.

[0160] [Storage stability of standard solutions for calibrating hemocytometers] The storage stability of the standard solution for calibrating hemocytometers was evaluated using an Elma PC602 hemocytometer from the amount of change in the measured particle count over time for the dispersion on the day of preparation and after 180 days of storage at room temperature. The results of the evaluation based on the following criteria are shown in Table 2. A rating of 2 or higher was considered to indicate that the storage stability of the standard solution for calibrating hemocytometers was good. 3: Less than 10% 2: 10% or more, less than 20% 1:20% or more

[0161] [Accuracy of blood cell counter measurements] The measurement accuracy of the standard solution for calibrating blood cell counters using electrical resistance detection was evaluated based on the amount of discrepancy between the hematocrit value determined from the number of particles dispersed in the standard solution measured using an Elma PC602 blood cell counter, and the hematocrit value determined by the centrifugation method. The results of the evaluation based on the following criteria are shown in Table 2. A rating of 2 or higher was deemed to indicate that the calibration accuracy of the standard solution for calibrating blood cell counters was good. 3: Less than 10% 2: 10% or more, less than 20% 1:20% or more

[0162] [Table 2]

[0163] From Tables 1 and 2, the average circularity is 0.95 or more and 0.985 or less, the volume average particle size is 2 μm or more and 10 μm or less, the coefficient of variation of the particle size is 2.7% or more and 10.3% or less, the aspect ratio is 1.3 or more and 5.0 or less, the density of the carboxyl group on the surface is 0.001, The density of the carboxyl groups is 0.001 / Å 2 More than 12 pieces / Å 2 The standard solutions for calibrating hemocytometers containing the following resin particles were excellent in both calibration accuracy and storage stability (Examples 1 to 10).

[0164] In contrast, a standard solution for calibrating a hemocytometer containing resin particles with a volume average particle size of less than 2 μm had poor storage stability (Comparative Example 1), and a standard solution for calibrating a hemocytometer containing resin particles with an average circularity of more than 0.99 had poor calibration accuracy (Comparative Example 2).

[0165] These results demonstrate that a standard solution for calibrating a hemocytometer made of resin particles with an average circularity of 0.99 or less and a volume average particle size of 2 μm to 10 μm can have excellent calibration accuracy and storage stability.

[0166] Although an embodiment of the present invention has been described above, the present invention is not limited to a specific embodiment, and various modifications and changes are possible within the scope of the invention described in the claims. [Prior art documents] [Patent documents]

[0167] [Patent Document 1] Japanese Patent Application Publication No. 01-301166

Claims

1. A standard solution for calibrating a blood cell counter containing resin particles, The resin particles have an average circularity of 0.99 or less, The volume average particle size of the resin particles is 2 μm or more and 10 μm or less. Standard solution for calibrating hemocytometers.

2. The coefficient of variation of the particle size of the resin particles is 15% or less. The standard solution for calibrating a blood cell counter according to claim 1.

3. The average circularity of the resin particles is 0.95 or more and 0.985 or less.

3. The standard solution for calibrating a blood cell counter according to claim 1 or 2.

4. The resin particles have an aspect ratio of 1.3 or more and 5.0 or less. The standard solution for calibrating a blood cell counter according to any one of claims 1 to 3.

5. The resin particles have a carboxyl group on their surfaces. The standard solution for calibrating a blood cell counter according to any one of claims 1 to 4.

6. The density of the carboxyl groups is 0.001 / Å ２ That's all. The standard solution for calibrating a blood cell counter according to claim 5.

7. A standard solution for calibrating a blood cell counter containing resin particles, The resin particles have an average circularity of 0.99 or less. Standard solution for calibrating hemocytometers.

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