Particle size-controlling agent for inorganic ultrafine particle slurry and inorganic ultrafine particle slurry

Abstract

The purpose of the present invention is to provide a particle size-controlling agent for an inorganic ultrafine particle slurry, said agent being capable of controlling the volume average particle size (D50, dynamic light scattering method) of inorganic ultrafine particles in the inorganic ultrafine particle slurry to be 100 nm or less. The present invention is a particle size-controlling agent for an inorganic ultrafine particle slurry, said agent being characterized by being composed of a salt (B), which is a salt of a C2-7 hydroxycarboxylic acid and ammonia or a C1-14 organic amine. The salt (B) is preferably composed of 100 parts by mole of the hydroxycarboxylic acid and 50 to 350 parts by mole of the ammonia or organic amine.

Description

Particle size control agent for inorganic ultrafine particle slurry and inorganic ultrafine particle slurry

[0001] The present invention relates to a particle size control agent for an inorganic ultrafine particle slurry and an inorganic ultrafine particle slurry.

[0002] Inorganic fine particle slurries are widely used in paints, ceramics, inks, etc., but in recent years, for the purpose of improving performance (improving surface roughness, etc.), it has become desirable to control the volume average particle diameter (D50, dynamic light scattering method) of the inorganic ultrafine particles in the inorganic ultrafine particle slurry to 100 nm or less.

[0003] However, no method or particle size control agent is known for controlling the volume average particle size (D50, dynamic light scattering method) of inorganic ultrafine particles in an inorganic ultrafine particle slurry to 100 nm or less. An object of the present invention is to provide a particle size control agent for an inorganic ultrafine particle slurry that can control the volume average particle size (D50, dynamic light scattering method) of inorganic ultrafine particles in an inorganic ultrafine particle slurry to 100 nm or less.

[0004] The particle size control agent for inorganic ultrafine particle slurry of the present invention is characterized in that it is composed of a salt (B) of a hydroxycarboxylic acid having 2 to 7 carbon atoms and ammonia or an organic amine having 1 to 14 carbon atoms.

[0005] The inorganic ultrafine particle slurry of the present invention is characterized in that it contains the above-mentioned particle size control agent for inorganic ultrafine particle slurry, inorganic ultrafine particles (A), and water (C), and that the volume average particle size (D50, dynamic light scattering method) of the inorganic ultrafine particles (A) in the slurry is 100 nm or less.

[0006] The manufacturing method of the present invention is characterized in that it is a method for manufacturing the above-mentioned inorganic ultrafine particle slurry, and is prepared by a rotation process using beads and disks having a diameter of 0.01 to 1 mm.

[0007] The particle size control agent for inorganic ultrafine particle slurry of the present invention can easily control the volume average particle size (D50, dynamic light scattering method) of the inorganic ultrafine particles in the inorganic ultrafine particle slurry to 100 nm or less.

[0008] Since the inorganic ultrafine particle slurry of the present invention contains the particle size control agent for inorganic ultrafine particle slurries, the volume average particle size (D50, dynamic light scattering method) of the inorganic ultrafine particles in the inorganic ultrafine particle slurry can be easily adjusted to 100 nm or less, and performance improvements (improvement of surface roughness, etc.) can be easily achieved in the fields of paints, ceramics, inks, etc.

[0009] According to the production method of the present invention, the particle size control agent for inorganic ultrafine particle slurry is used, so that an inorganic ultrafine particle slurry in which the volume average particle size (D50, dynamic light scattering method) of the inorganic ultrafine particles in the inorganic ultrafine particle slurry is 100 nm or less can be easily prepared.

[0010] Examples of hydroxycarboxylic acids having 2 to 7 carbon atoms include monohydroxymonocarboxylic acids (glycolic acid, lactic acid, 2-hydroxybutyric acid, 3-hydroxybutyric acid, γ-hydroxybutyric acid, L-leucinic acid, etc.), monohydroxydicarboxylic acids (malic acid, tartronic acid, citramalic acid, etc.), monohydroxytricarboxylic acids (citric acid, isocitric acid, etc.), dihydroxymonocarboxylic acids (glyceric acid, mevalonic acid, pantoic acid, etc.), dihydroxydicarboxylic acids (tartaric acid, etc.), pentahydroxymonocarboxylic acids (gluconic acid, etc.), and tetrahydroxymonocarboxylic acids (glucoheptonic acid, etc.). Of these, monohydroxymonocarboxylic acids, monohydroxydicarboxylic acids, monohydroxytricarboxylic acids, dihydroxydicarboxylic acids, and pentahydroxymonocarboxylic acids are preferred from the viewpoint of ease of controlling the volume average particle size (D50, dynamic light scattering method) of the inorganic ultrafine particles in the inorganic ultrafine particle slurry to 100 nm or less.

[0011] Among ammonia and organic amines having 1 to 14 carbon atoms, ammonia is inorganic ammonia (NH ３), and examples of the organic amine having 1 to 14 carbon atoms include monoamines {monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, tert-butylamine, pyrrolidine, pyridine, monohydroxymonoamines (monoethanolamine, N-methylethanolamine, dimethylaminoethanol, 2-amino-2-methyl-1-propanol, 1-amino-2-methyl-2-propanol, DL-isopropanolamine, propanolamine, etc.), dihydroxymonoamines (diethanolamine, methyldiethanolamine, etc.), trihydroxymonoamines (monomethylamine, dimethylaminoethanol, 2-amino-2-methyl-1-propanol, 1-amino-2-methyl-2-propanol, DL-isopropanolamine, propanolamine, etc.), Examples of suitable amines include amines (such as triethanolamine) and pentahydroxymonoamines (such as D-glucamine, N-methyl-D(-)-glucamine, and N-n-octyl-D-glucamine), diamines (such as ethylenediamine, putrescine (tetramethylenediamine), cadaverine (pentamethylenediamine), hexamethylenediamine, dimethylaminopropylamine, norbornanediamine, N,N-dimethyltrimethylenediamine, 1,3-bisaminomethylcyclohexane, and piperazine), and triamines (such as diethylenetriamine, pentamethyldiethylenetriamine, and dipropylenetriamine). Among these, from the viewpoint of ease of controlling the volume average particle size (D50, dynamic light scattering method) of the inorganic ultrafine particles in the inorganic ultrafine particle slurry to 100 nm or less, ammonia and monoamines are preferred, more preferably ammonia, monohydroxymonoamines, dihydroxymonoamines, and trihydroxymonoamines, and particularly preferably ammonia, monohydroxymonoamines, and dihydroxymonoamines.

[0012] The salt (B) is preferably composed of 100 molar parts of a hydroxycarboxylic acid and 50 to 350 (preferably 100 to 330, more preferably 160 to 300) molar parts of ammonia or an organic amine. Within this range, the volume average particle size (D50, dynamic light scattering method) of the inorganic ultrafine particles in the inorganic ultrafine particle slurry can be more easily controlled to 100 nm or less.

[0013] The particle size control agent for inorganic ultrafine particle slurries of the present invention can be produced by neutralizing a hydroxycarboxylic acid having 2 to 7 carbon atoms with ammonia or an organic amine having 1 to 14 carbon atoms in a solvent (water, lower alcohol, etc.) that can dissolve the hydroxycarboxylic acid. After preparing the salt (B), the solvent may be removed (by filtration, distillation, etc.), or the salt may be used as is. The particle size control agent for inorganic ultrafine particle slurries of the present invention may also be diluted with water before use. The concentration is not particularly limited, but a concentration of 20 to 60% by weight (water concentration: 40 to 80% by weight) is preferred. The water is preferably the water described below.

[0014] The inorganic ultrafine particles that can be used in the particle size control agent for inorganic ultrafine particle slurries of the present invention are not limited as long as they are mixed with water in the production process of paints, dielectrics, inks, ceramics, etc. (including intermediates and final products), and include metal oxides, metal hydroxides, and metal carbonates.

[0015] Examples of metal oxides include titanium oxide, zinc oxide, alumina, iron oxide, magnesium oxide, silica, zirconia, and boehmite.

[0016] Examples of metal hydroxides include aluminum hydroxide, magnesium hydroxide, calcium hydroxide, and iron hydroxide.

[0017] Examples of metal carbonates include calcium carbonate, barium carbonate, and magnesium carbonate.

[0018] Among these inorganic ultrafine particles, metal oxides are preferred from the viewpoint of ease of controlling the volume average particle size (D50, dynamic light scattering method) of the inorganic ultrafine particle in the inorganic ultrafine particle slurry to 100 nm or less.

[0019] The inorganic ultrafine particles (A) contained in the inorganic ultrafine particle slurry of the present invention can be the inorganic ultrafine particles described above, with the preferred ranges being as described above. Furthermore, the particle size control agent can be the particle size control agent described above, with the preferred ranges being as described above. Examples of water (C) include tap water, ion-exchanged water, distilled water, and the A1 to A3 (pure water) and A4 (ultrapure water) specified in JIS K0557:1998 "Water for use in testing water and wastewater." Of these, ion-exchanged water, distilled water, and the A1 to A3 (pure water) and A4 (ultrapure water) specified in JIS K0557:1998 are preferred.

[0020] The volume average particle diameter (nm, D50, dynamic light scattering method) of the inorganic ultrafine particles (A) in the slurry is preferably 100 or less, more preferably 50 or less. The measurement limit of the particle diameter (nm, dynamic light scattering method) is about 0.1 nm.

[0021] The volume average particle size is measured at 25°C using a nanoparticle analyzer (for example, nanoPartica SZ-100, Horiba, Ltd.) in accordance with JIS Z8828:2019 "Particle size analysis - dynamic light scattering" (corresponding international standard: ISO 22412:2017, Particle size analysis - Dynamic light scattering (DLS) (IDT)). The volume average particle size (D50, dynamic light scattering) refers to the median diameter (D50, dynamic light scattering), which is the particle size that shows the 50% integrated value of the integrated distribution curve.

[0022] In the inorganic ultrafine particle slurry of the present invention, the content (parts by weight) of the particle size control agent relative to 100 parts by weight of the inorganic ultrafine particles (A) is preferably 5 to 50, more preferably 8 to 30, and particularly preferably 10 to 20. Within this range, the volume average particle size (D50, dynamic light scattering method) of the inorganic ultrafine particles in the inorganic ultrafine particle slurry can be more easily controlled to 100 nm or less.

[0023] The inorganic ultrafine particle slurry of the present invention may contain, in addition to the inorganic fine particles (A), the particle size control agent, and water (C), known additives, etc., within a range that does not impair the effects of the present invention. Examples of additives include antifoaming agents, dispersants, viscosity reducers, wetting agents, and surface treatment agents.

[0024] As the rotary processing device that can be used in the method for producing an inorganic ultrafine particle slurry of the present invention, any known rotary processing device that uses beads and disks can be used, and examples thereof include a tower mill, a ball mill, a sand mill, a pearl mill, and a bead mill.

[0025] The diameter (mm) of the beads is preferably 0.01 to 1, and more preferably 0.1 to 0.2. Within this range, the volume average particle size (D50, dynamic light scattering method) of the inorganic ultrafine particles in the inorganic ultrafine particle slurry can be more easily controlled to 100 nm or less.

[0026] The material of the beads is not particularly limited, and examples thereof include glass and zirconia, with zirconia being preferred.

[0027] Unless otherwise specified, "parts" means parts by weight and "%" means % by weight.

[0028] Example 1 10,179 parts (100 molar parts as lactic acid) of lactic acid (special reagent grade, containing 11.5% water, Fujifilm Wako Pure Chemical Industries, Ltd.) (b11), 3,036 parts (50 molar parts as ammonia) of a 28% aqueous solution of ammonia (b21) (Nacalai Standard Grade 1, Nacalai Tesque Inc.), and 11,431 parts of water were uniformly mixed to obtain an aqueous solution containing the particle size control agent of the present invention (B1; an aqueous solution of ammonium lactate with a concentration of 40%).

[0029] Example 2 39,232 parts (100 parts by mole as gluconic acid) of an aqueous solution of gluconic acid (b12) (50%, Fujifilm Wako Pure Chemical Industries, Ltd.), 8,914 parts (100 parts by mole) of dimethylaminoethanol (b22) (purity >99.0%, Tokyo Chemical Industry Co., Ltd.), and 23,179 parts of water were uniformly mixed to obtain an aqueous solution containing the particle size control agent of the present invention (B2; an aqueous solution of dimethylaminoethanol gluconate salt with a concentration of 40%).

[0030] Example 3 13,409 parts (100 parts by mole) of L(-)-malic acid (Wako Grade 1, Fujifilm Wako Pure Chemical Industries, Ltd.) (b13), 16,822 parts (160 parts by mole) of diethanolamine (purity >99.0%, Tokyo Chemical Industry Co., Ltd.) (b23), and 45,348 parts of water were uniformly mixed to obtain an aqueous solution containing the particle size control agent of the present invention (B3; an aqueous solution of L(-)-malic acid diethanolamine salt with a concentration of 40%).

[0031] Example 4 15,009 parts (100 parts by mole) of L(+)-tartaric acid (special reagent grade, Fujifilm Wako Pure Chemical Industries, Ltd.) (b14), 12,216 parts (200 parts by mole) of monoethanolamine (purity >99.0%, Tokyo Chemical Industry Co., Ltd.) (b24), and 40,837 parts of water were uniformly mixed to obtain an aqueous solution containing the particle size control agent of the present invention (B4; an aqueous solution of L(+)-tartaric acid monoethanolamine salt with a concentration of 40%).

[0032] Example 5 19,212 parts (100 parts by mole) of citric acid anhydride (Wako special grade, FUJIFILM Wako Pure Chemical Industries, Ltd.) (b15), 28,449 parts (300 parts by mole) of 2-amino-2-methyl-1-propanol (purity >93.0%, Wako first grade, FUJIFILM Wako Pure Chemical Industries, Ltd.) (b25), and 67,224 parts of water were uniformly mixed to obtain an aqueous solution containing the particle size control agent of the present invention (B5; a 40% aqueous solution of 2-amino-2-methyl-1-propanol citrate salt).

[0033] Example 6 3.5 g of an aqueous solution (B1) containing a particle size control agent, 14 g of inorganic fine particles (a1) {AEROXIDE P-90, Evonik Japan Co., Ltd., fumed titanium dioxide; "AEROXIDE" is a registered trademark of Evonik Operations GmbH}, 56 g of water (c), and 210 g of zirconia beads (Torenceram, particle size: 0.1 mm, Toray Industries, Inc.; "Torenceram" is a registered trademark of the same company) were placed in a vessel (type 2) of a bead mill (Easy Nano RMB II type, Imex Co., Ltd.) and subjected to a disk rotation treatment for 60 minutes to obtain an inorganic ultrafine particle slurry (1) of the present invention.

[0034] Example 7 An inorganic ultrafine particle slurry (2) of the present invention was obtained in the same manner as in Example 6, except that the “aqueous solution (B1) containing a particle size control agent” was changed to the “aqueous solution (B2) containing a particle size control agent.”

[0035] Example 8 An inorganic ultrafine particle slurry (3) of the present invention was obtained in the same manner as in Example 6, except that "3.5 g of aqueous solution (B1) containing a particle size control agent" was changed to "7.0 g of aqueous solution (B3) containing a particle size control agent."

[0036] Example 9 An inorganic ultrafine particle slurry (4) of the present invention was obtained in the same manner as in Example 6, except that the "aqueous solution (B1) containing a particle size control agent" was changed to the "aqueous solution (B4) containing a particle size control agent" and the "inorganic fine particles (a1)" were changed to "inorganic fine particles (a2) {AEROXIDE P-25, Evonik Japan Co., Ltd., fumed titanium dioxide}."

[0037] Example 10 An inorganic ultrafine particle slurry (5) of the present invention was obtained in the same manner as in Example 6, except that the “aqueous solution containing a particle size control agent (B1)” was changed to the “aqueous solution containing a particle size control agent (B5)” and the “inorganic fine particles (a1)” was changed to the “inorganic fine particles (a2)”.

[0038] Example 11 An inorganic ultrafine particle slurry (6) of the present invention was obtained in the same manner as in Example 6, except that "3.5 g of an aqueous solution (B1) containing a particle size control agent" was changed to "5.3 g of an aqueous solution (B1) containing a particle size control agent" and "inorganic fine particles (a1)" was changed to "inorganic fine particles (a3) ​​{boehmite C06, Taimei Chemical Industry Co., Ltd.}".

[0039] Comparative Example A comparative inorganic ultrafine particle slurry (H) was obtained in the same manner as in Example 6, except that the "aqueous solution (B1) containing a particle size control agent" was not used.

[0040] Using the inorganic ultrafine particle slurries (1) to (6) obtained in the examples and the inorganic ultrafine particle slurry (H) obtained in the comparative example, the volume average particle diameter and surface roughness of the slurries were measured as follows, and the results are summarized in the table below.

[0041] 1. Measurement of Volume Average Particle Diameter Using a nanoparticle analyzer (nanoPartica SZ-100, manufactured by Horiba, Ltd.), the median diameter (D50, dynamic light scattering method), which is the particle diameter showing the 50% volume integrated value of the integrated distribution curve, was taken as the volume average particle diameter (D50).

[0042] The inorganic ultrafine particle slurry (H) obtained in the comparative example had a wide particle size distribution that exceeded the measurement range of the nanoparticle analyzer. Furthermore, the coarse particles settled within a short period of time, making it impossible to measure the volume average particle diameter (D50, dynamic scattering method). Therefore, for comparison, the volume average particle diameter (D50, laser diffraction / scattering method) was measured using a particle size distribution analyzer (Partica LA-960V2, Horiba, Ltd., JIS Z 8825:2022 Particle size analysis - laser diffraction / scattering method (corresponding international standard: ISO 13320:2020, Particle size analysis - Laser diffraction methods)). However, due to the measurement principle, this method does not have a measurement accuracy of 100 nm or less.

[0043] 2. Measurement of Surface Roughness A measurement sample (inorganic ultrafine particle slurry) was applied to a polyethylene terephthalate film (wet thickness: 10 μm), and then dried at 70° C. for 30 minutes to form a coating film. Next, the arithmetic mean roughness (Ra) of the coating film (JIS B 0601:2013 “Geometrical Product Specifications (GPS) - Surface texture: Profile method - Terms, definitions and surface texture parameters” (corresponding international standard: ISO 4281:1997, Amd.(2009), Geometrical Product Specifications (GPS) - Surface texture: Profile method - Terms, definitions and surface texture parameters)) was measured using a nano-roughness height measuring device (Nano Seven TN-A1, Tsukumo Engineering Co., Ltd., JIS B0633:2001 “Geometrical Product Specifications (GPS) - Surface texture: Profile method - Rules and procedures for the assessment of surface texture” (corresponding international standard: ISO 4288:1996, Geometrical Product Specifications (GPS) - Surface texture: Profile method - Rules and procedures for the assessment of surface texture)).

[0044]

[0045] As described above, by using the particle size control agent for inorganic ultrafine particle slurry of the present invention, the volume average particle size (D50, dynamic light scattering method) of the inorganic ultrafine particles in the inorganic ultrafine particle slurry can be easily controlled to 100 nm or less, and an inorganic ultrafine particle slurry having a volume average particle size (D50, dynamic light scattering method) of the inorganic ultrafine particles in the inorganic ultrafine particle slurry of 100 nm or less can be easily prepared. Furthermore, the inorganic ultrafine particle slurry of the present invention has a better surface roughness than the comparative slurry, and performance can be easily improved.

Claims

1. A particle size control agent for an inorganic ultrafine particle slurry, which comprises (B) a salt of a hydroxycarboxylic acid having 2 to 7 carbon atoms and ammonia or an organic amine having 1 to 14 carbon atoms.

2. The particle size control agent for inorganic ultrafine particle slurry according to claim 1, wherein the salt (B) comprises 100 parts by mole of a hydroxycarboxylic acid and 50 to 350 parts by mole of ammonia or an organic amine.

3. A particle size control agent for an inorganic ultrafine particle slurry according to claim 1, wherein the inorganic ultrafine particles are metal oxides.

4. An inorganic ultrafine particle slurry comprising the particle size control agent for inorganic ultrafine particle slurry according to claim 1, inorganic ultrafine particles (A) and water (C), wherein the volume average particle size (D50, dynamic light scattering method) of the inorganic ultrafine particles (A) in the slurry is 100 nm or less.

5. The inorganic ultrafine particle slurry according to claim 4, wherein the particle size control agent is contained in an amount of 5 to 50 parts by weight per 100 parts by weight of the inorganic ultrafine particles (A).

6. A slurry of inorganic ultrafine particles according to claim 4, wherein the inorganic ultrafine particles (A) are metal oxides.

7. A method for producing the inorganic ultrafine particle slurry according to claim 4, characterized in that it is prepared by a rotary process using beads and disks having a diameter of 0.01 to 1 mm.

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