WO2014126075A1 - Rod-like magnesium hydroxide particle and rod-like magnesium oxide particle each having high specific surface area, and methods respectively for producing said particles - Google Patents

Rod-like magnesium hydroxide particle and rod-like magnesium oxide particle each having high specific surface area, and methods respectively for producing said particles Download PDF

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WO2014126075A1
WO2014126075A1 PCT/JP2014/053108 JP2014053108W WO2014126075A1 WO 2014126075 A1 WO2014126075 A1 WO 2014126075A1 JP 2014053108 W JP2014053108 W JP 2014053108W WO 2014126075 A1 WO2014126075 A1 WO 2014126075A1
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magnesium oxide
particles
magnesium hydroxide
metal elements
surface area
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PCT/JP2014/053108
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French (fr)
Japanese (ja)
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黒田　明
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タテホ化学工業株式会社
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Priority to KR1020157022195A priority Critical patent/KR102156105B1/en
Priority to CN201480008719.8A priority patent/CN105008281B/en
Publication of WO2014126075A1 publication Critical patent/WO2014126075A1/en

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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
    • C01F5/00—Compounds of magnesium
    • C01F5/02—Magnesia
    • C01F5/06—Magnesia by thermal decomposition of magnesium compounds
    • C01F5/08—Magnesia by thermal decomposition of magnesium compounds by calcining magnesium hydroxide
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
    • C01F5/00—Compounds of magnesium
    • C01F5/14—Magnesium hydroxide
    • C01F5/16—Magnesium hydroxide by treating magnesia, e.g. calcined dolomite, with water or solutions of salts not containing magnesium
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/10—Particle morphology extending in one dimension, e.g. needle-like
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/50—Agglomerated particles
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/60—Particles characterised by their size
    • C01P2004/61—Micrometer sized, i.e. from 1-100 micrometer
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/12—Surface area

Definitions

  • the present invention relates to rod-shaped magnesium hydroxide particles having a high specific surface area, rod-shaped magnesium oxide particles, and methods for producing them.
  • Magnesium hydroxide particles and magnesium oxide particles are used in various fields. Applications of magnesium hydroxide particles include inkjet paper coating agents, flame retardants, heat storage materials, catalysts and electronic materials. Magnesium oxide particles applications include optical materials, inkjet paper coating agents, catalysts and electronics. Materials and the like.
  • magnesium hydroxide particles are used for inkjet paper coating agents, flame retardants, heat storage materials, catalysts, and electronic materials, the following are desired.
  • the aggregate structure has a positive charge that is easy to adsorb on the pigment ink having a high affinity with many OH groups and many negative charges in the dye ink, and the dye can easily penetrate between particles.
  • magnesium hydroxide particles having In addition, in the flame retardant, the heat storage material, and the catalyst, magnesium hydroxide particles having an aggregate structure exhibiting excellent dispersibility and high reactivity are demanded. Further, in electronic materials, small magnesium hydroxide particles having excellent dispersibility are required.
  • magnesium oxide particles are used in applications such as optical materials, inkjet paper coating agents, catalysts, and electronic materials, the following are desired.
  • optical materials there is a demand for magnesium oxide particles having an aggregate structure that is excellent in dispersibility and easily diffuses light.
  • magnesium oxide particles having an aggregate structure that has excellent dispersibility and high reactivity are required.
  • small magnesium oxide particles having excellent dispersibility are required for electronic materials.
  • Patent Document 1 discloses that the ion concentration ratio of sulfate ion [(SO 4 ) 2 ⁇ ] / magnesium ion [(Mg) 2+ ] is in the range of 0.3 to 2.0.
  • Spherical magnesium hydroxide particles having a structure in which leaflets in different directions are joined and / or crossed are described.
  • the method described in Patent Document 1 cannot stably form spherical magnesium hydroxide, and plate-like and columnar magnesium hydroxide are mixed, and such magnesium hydroxide particles are dispersed in a resin or the like.
  • the specific surface area is low and the reactivity is low.
  • An object of the present invention is to provide magnesium hydroxide particles and magnesium oxide particles having a high specific surface area, and methods for producing them.
  • the inventor has added divalent and trivalent metal element chlorides, divalent and trivalent to a dispersion containing one or more compounds selected from the group consisting of Zn, Zr, Hf, and Ti.
  • a reaction solution obtained by adding one or more compounds selected from the group consisting of nitrates of metal elements (excluding Zn, Zr, Hf, and Ti compounds) and further adding an organic acid; and a constant temperature Mixing with acicular magnesium oxide particles partially hydrated the surface of acicular magnesium oxide particles with a humidity controller etc., and by hydration reaction under high shear, excellent dispersibility, It has been found that highly reactive magnesium hydroxide particles having a high specific surface area can be obtained. Further, the present inventors have found that magnesium oxide particles having a high specific surface area can be obtained by firing the magnesium hydroxide particles of the present invention at 500 ° C. to 1400 ° C. in an air atmosphere.
  • the present invention is a rod-like aggregate of scaly primary particles, the volume cumulative 50% particle diameter (D 50 ) measured by laser diffraction / scattering particle size distribution measurement is 1.0 to 10.0 ⁇ m, and the specific surface area Relates to magnesium hydroxide particles having a particle size of 10 m 2 / g or more.
  • the present invention further includes one or more metal elements selected from the group consisting of Zn, Zr, Hf, and Ti in an amount of 0.1 to 5.0% by mass in terms of metal elements, and bivalent and trivalent metal elements
  • the hydroxide according to the above, containing 0.1 to 5.0% by mass of one or more additional metal elements selected from the group consisting of Zn (excluding Zn, Zr, Hf, and Ti) in terms of metal elements It relates to magnesium particles.
  • the present invention is a rod shape in which scaly primary particles are aggregated, the volume cumulative 50% particle diameter (D 50 ) measured by laser diffraction scattering type particle size distribution is 1.0 to 10.0 ⁇ m, and the specific surface area is 10 m.
  • the present invention further includes one or more metal elements selected from the group consisting of Zn, Zr, Hf, and Ti in an amount of 0.1 to 5.0% by mass in terms of metal elements, and bivalent and trivalent metal elements
  • metal elements selected from the group consisting of Zn, Zr, Hf, and Ti in an amount of 0.1 to 5.0% by mass in terms of metal elements, and bivalent and trivalent metal elements
  • the present invention is a method for producing magnesium hydroxide particles, (A) In a dispersion containing one or more compounds selected from the group consisting of Zn, Zr, Hf, and Ti, divalent and trivalent metal element chlorides, and divalent and trivalent metals Adding one or more compounds selected from the group consisting of elemental nitrates (excluding Zn, Zr, Hf, and Ti compounds), and further adding an organic acid to obtain a reaction solution; (B) The reaction liquid in step (a) and the volume cumulative 50% particle diameter (D 50 ) measured by laser diffraction / scattering particle size distribution measurement are 0.1 to 10 ⁇ m, and the specific surface area is 1.0 to 20.0 m.
  • a partially hydrated acicular magnesium oxide is mixed to obtain a mixture (where, One or more compounds selected from the group consisting of compounds of Zn, Zr, Hf, and Ti are 0.1 to 5.0% by mass in terms of metal elements with respect to partially hydrated acicular magnesium oxide. , One or more compounds selected from the group consisting of divalent and trivalent metal element chlorides, and divalent and trivalent metal element nitrates are partially hydrated with acicular magnesium oxide.
  • the organic acid is 0.01 to 3.0 mol with respect to 100 g of partially hydrated acicular magnesium oxide)
  • C mixing the liquid mixture of step (b) at a temperature of 50 to 100 ° C. using a stirrer having a peripheral speed of 7 to 20 m / s,
  • D a step of obtaining a magnesium hydroxide slurry by stirring at a temperature of 30 to 100 ° C., and
  • e filtering, washing with water and drying the magnesium hydroxide slurry of step (d) to obtain magnesium hydroxide particles.
  • the present invention relates to a method for producing magnesium hydroxide particles, including a step.
  • the partially hydrated acicular magnesium oxide in the step (b) has a volume cumulative 50% particle diameter (D 50 ) of 0.1 to 10 ⁇ m by laser diffraction scattering type particle size distribution measurement, and has a specific surface area of Obtained by placing acicular magnesium oxide particles of 1.0 to 15.0 m 2 / g in a thermo-hygrostat at a temperature of 40 to 95 ° C. and a humidity of 60 to 95% for 0.5 to 24 hours, Relates to the method described in.
  • the present invention relates to the method as described above, wherein the concentration of the partially hydrated acicular magnesium oxide in the mixed solution of step (b) is 20 to 200 g / L.
  • the present invention is a method for producing magnesium oxide particles, the step of firing the magnesium hydroxide particles described above or the magnesium hydroxide particles obtained by the method described above at 500 to 1400 ° C. in an air atmosphere.
  • the present invention provides rod-shaped magnesium hydroxide particles and magnesium oxide particles in which scaly primary particles having a high specific surface area are aggregated, and methods for producing them.
  • the magnesium hydroxide particles and magnesium oxide particles of the present invention have a high specific surface area and dispersibility, and are useful in various fields.
  • the magnesium hydroxide particle and magnesium oxide particle which have a high specific surface area and a dispersibility can be manufactured easily.
  • the magnesium hydroxide particles of the present invention are rod-like aggregates of scaly primary particles, and the volume cumulative 50% particle diameter (D 50 ) measured by laser diffraction scattering type particle size distribution is 1.0 to 10.0 ⁇ m.
  • the specific surface area is 10 m 2 / g or more.
  • the shape of the primary particles of the present invention is scaly.
  • An example of a scale-like shape is shown in FIG.
  • the scaly primary particles of the present invention have a thickness in the range of 0.01 to 0.1 ⁇ m, preferably 0.01 to 0.05 ⁇ m, and the diameter of the circumscribed circle of the surface is 0.2 to 5 ⁇ m, preferably 0. The range is from 5 to 2.5 ⁇ m.
  • a rod-like particle is a particle in which scaly primary particles are aggregated and has an aspect ratio (particle length L / particle cross-sectional diameter D) of 1.5 to 20, preferably 2 to 10.
  • the needle shape refers to particles having an aspect ratio (particle length L / particle cross-sectional diameter D) of 21 to 1000, preferably 50 to 500.
  • L is in the range of 0.1 to 10 ⁇ m
  • D is specifically in the range of 0.001 to 0.5 ⁇ m.
  • the spherical shape refers to particles having a spherical shape in which the primary particles of the scales are aggregated and having an aspect ratio (particle length L / particle cross-sectional diameter D) in the range of 1.0 to 1.2. .
  • L is specifically in the range of 1 to 20 ⁇ m
  • D is specifically in the range of 1 to 20 ⁇ m.
  • Such rod-like particles in which primary particles are aggregated have uniform pores on the particle surface, and hexagonal plate-like magnesium hydroxide particles obtained by a conventional production method (see JP 2006-306658 A). Compared with the high specific surface area, the adsorptivity of liquid and gas molecules is high. In addition, when such rod-shaped particles in which primary particles are aggregated are used as a coating agent for paper, the scale-like magnesium hydroxide constituting the rod-shaped particles is not too dense, and thus the ink adsorption is good. It is.
  • the magnesium hydroxide particles of the present invention are rod-like aggregates of scaly primary particles, and the volume cumulative 50% particle diameter (D 50 ) measured by laser diffraction scattering type particle size distribution is 1.0 to 10.0 ⁇ m.
  • the specific surface area is 10 m 2 / g or more. Within such a range, the viscosity does not become too high when blended with a resin or the like, and the agglomeration of particles is suppressed, so that the dispersibility is good.
  • the magnesium hydroxide particles having such a particle size are used as a paper coating agent, the ink fixing and absorbing properties are good. Furthermore, since the particle diameter is not too large, it is useful for optical materials and electronic materials.
  • the volume cumulative 50% particle diameter (D 50 ) of the magnesium hydroxide particles of the present invention as measured by laser diffraction scattering type particle size distribution is preferably 2.0 to 9.0 ⁇ m, more preferably 3.0 to 8.
  • the specific surface area is preferably 10 to 200 m 2 / g, more preferably 20 to 150 m 2 / g. In the present invention, the specific surface area is determined by the BET method.
  • the magnesium hydroxide particles of the present invention preferably have a ratio D 90 / D 10 of the volume-based cumulative 10% particle diameter (D 10 ) and cumulative 90% particle diameter (D 90 ) by laser diffraction scattering particle size distribution measurement. Is 10 or less, more preferably in the range of 1-8. With such a ratio D 90 / D 10, narrow particle size distribution of the magnesium hydroxide particles, since aggregation of particles is small, it can be obtained more excellent dispersibility.
  • the magnesium hydroxide particles of the present invention may further contain a metal element of a compound used in the production process.
  • the magnesium hydroxide particles of the present invention contain one or more metal elements selected from the group consisting of Zn, Zr, Hf, and Ti in an amount of 0.1 to 5.0% by mass in terms of metal elements, and are divalent and Containing 0.1 to 5.0% by mass of one or more additional metal elements selected from the group consisting of trivalent metal elements (excluding Zn, Zr, Hf, and Ti) in terms of metal elements Can do.
  • these metal element contents whiteness, ultraviolet absorption, refractive index, and the like are sufficient when magnesium hydroxide particles are used as the coating agent.
  • the content of one or more metal elements selected from the group consisting of Zn, Zr, Hf, and Ti, that is, Zn, Zr, Hf, Ti, or a mixture thereof is preferably 0.2 to It is 4.0% by mass, and more preferably 0.3 to 3.0% by mass.
  • one or more additional metal elements selected from the group consisting of divalent and trivalent metal elements are not particularly limited, and Ag, Examples include Al, B, Ba, Bi, Ca, Cd, Co, Cr, Cu, Fe, Ga, In, Mn, Mo, Ni, Pb, Sr, Tl, and V, and Al and Fe are preferable.
  • the content of one or more additional metal elements selected from the group consisting of divalent and trivalent metal elements (excluding Zn, Zr, Hf, and Ti) is 0.1 to The amount is 5.0% by mass, preferably 0.2 to 4.0% by mass, and more preferably 0.3 to 3.0% by mass.
  • the magnesium oxide particles of the present invention are rod-like aggregates of scaly primary particles, and the 50% particle diameter (D 50 ) of volume accumulation by laser diffraction scattering type particle size distribution measurement is 1.0 to 10.0 ⁇ m, The specific surface area is 10 m 2 / g or more.
  • the shape of the primary particles of the present invention is scaly and is similar to the scaly example of FIG.
  • the scaly primary particles of the present invention have a thickness in the range of 0.01 to 0.1 ⁇ m, preferably 0.01 to 0.05 ⁇ m, and the diameter of the circumscribed circle of the surface is 0.2 to 5 ⁇ m, preferably 0. The range is from 5 to 2.5 ⁇ m.
  • Such magnesium oxide particles have excellent dispersibility in a resin or the like.
  • magnesium oxide particles having such a particle size and specific surface area have good ink fixability and absorbability when used as a paper coating agent.
  • the viscosity does not become too high when blended with a resin or the like, and the agglomeration of particles is suppressed, so that the dispersibility is good.
  • the particle diameter is not too large, it is useful for optical materials and electronic materials.
  • the volume cumulative 50% particle diameter (D 50 ) of the magnesium oxide particles of the present invention as measured by laser diffraction scattering type particle size distribution is preferably 2.0 to 9.0 ⁇ m, more preferably 3.0 to 8.0 ⁇ m.
  • the specific surface area is preferably 10 to 200 m 2 / g, more preferably 20 to 150 m 2 / g.
  • the magnesium oxide particles of the present invention preferably have a ratio D 90 / D 10 of a volume-based cumulative 10% particle diameter (D 10 ) and cumulative 90% particle diameter (D 90 ) by laser diffraction scattering particle size distribution measurement. It is 10 or less, and more preferably in the range of 1-8. With such a ratio D 90 / D 10 , the particle size distribution of the magnesium oxide particles is narrow and the particles are less aggregated, so that further excellent dispersibility can be obtained.
  • the magnesium oxide particles of the present invention may further contain a metal element of a compound used in the production process.
  • the magnesium oxide particles of the present invention contain one or more metal elements selected from the group consisting of Zn, Zr, Hf, and Ti in an amount of 0.1 to 5.0% by mass in terms of metal elements, and are further divalent and 3
  • One or more additional metal elements selected from the group consisting of valent metal elements may be contained in an amount of 0.1 to 5.0% by mass in terms of metal elements it can. With these metal element contents, whiteness, ultraviolet absorptivity, refractive index, etc. are sufficient when magnesium oxide particles are used as a coating agent.
  • the content of one or more metal elements selected from the group consisting of Zn, Zr, Hf, and Ti, that is, Zn, Zr, Hf, Ti, or a mixture thereof is preferably 0.2 to It is 4.0% by mass, and more preferably 0.3 to 3.0% by mass.
  • One or more additional metal elements selected from the group consisting of divalent and trivalent metal elements are not particularly limited, and Ag, Al, B, Examples include Ba, Bi, Cd, Co, Cr, Cu, Fe, Ga, In, Mn, Mo, Ni, Pb, Sr, Tl, and V, and Al and Fe are preferable.
  • the content of one or more additional metal elements selected from the group consisting of divalent and trivalent metal elements (excluding Zn, Zr, Hf, and Ti) is preferably 0.00 in terms of metal elements. It is 2 to 4.0% by mass, and more preferably 0.3 to 3.0% by mass.
  • the method for producing magnesium hydroxide particles of the present invention comprises: (A) In a dispersion containing one or more compounds selected from the group consisting of Zn, Zr, Hf, and Ti, divalent and trivalent metal element chlorides, and divalent and trivalent metals Adding one or more compounds selected from the group consisting of elemental nitrates (excluding Zn, Zr, Hf, and Ti compounds), and further adding an organic acid to obtain a reaction solution; (B) The reaction liquid in step (a) and the volume cumulative 50% particle diameter (D 50 ) measured by laser diffraction / scattering particle size distribution measurement are 0.1 to 10 ⁇ m, and the specific surface area is 1.0 to 20.0 m.
  • Ig-loss is 2.0 to 25.0%, mixing partially hydrated acicular magnesium oxide to obtain a mixture, (here, One or more compounds selected from the group consisting of compounds of Zn, Zr, Hf, and Ti are 0.1 to 5.0% by mass in terms of metal elements with respect to partially hydrated acicular magnesium oxide. , One or more compounds selected from the group consisting of divalent and trivalent metal element chlorides and divalent and trivalent metal element nitrates are partially hydrated with acicular magnesium oxide.
  • the organic acid is 0.01 to 3.0 mol with respect to 100 g of partially hydrated acicular magnesium oxide
  • C a step of mixing the mixed liquid of step (b) using a stirrer having a peripheral speed of 7 to 20 m / s at a temperature of 50 to 100 ° C .
  • D a step of obtaining a magnesium hydroxide slurry by stirring at a temperature of 30 to 100 ° C., and (e) filtering, washing with water and drying the magnesium hydroxide slurry of step (d) to obtain magnesium hydroxide particles.
  • Step (a) is a step of obtaining a reaction solution for partially hydrating magnesium hydroxide.
  • One or more compounds selected from the group consisting of Zn, Zr, Hf, and Ti are added to produce the magnesium hydroxide particles and magnesium oxide particles of the present invention. Thereby, whiteness, ultraviolet absorption, refractive index and the like are improved, and the magnesium hydroxide and magnesium oxide particles of the present invention suitable for an optical material or a coating agent for inkjet paper can be obtained.
  • the compound of Zn, Zr, Hf, and Ti is not particularly limited as long as it is a compound having these metal elements, and is an oxide, hydroxide, hydride, halide (fluoride, chloride, bromide, and iodine).
  • the compound of Zn, Zr, Hf, and Ti preferably has a purity of 99.0% or more, and more preferably 99.5% or more.
  • purity refers to impurity elements (Ag, Al, B, Ba, Bi, Ca, Cd, Cl, Co, Cr, Cu, Fe, Ga, Hf, Zn, Zr, and Ti).
  • K, Li, Mg, Mn, Mo, Na, Ni, P, Pb, S, Si, Sr, Ti, Tl, V, Zn, and Zr) are measured, and the total content thereof is set to 100. The value is subtracted from the mass%.
  • the element constituting the target Zn, Zr, Hf, and Ti compound itself corresponds to the impurity element in the Zn, Zr, Hf, and Ti compound, the element is included in the impurity element. I can't.
  • Zn constituting ZnO is an impurity element in the compound of Zn, Zr, Hf, and Ti described above. Not included.
  • a measuring method of the content of these impurity elements a measuring method using an ICP emission analyzer can be mentioned.
  • the compound of Zn, Zr, Hf, and Ti preferably has a D 50 of 0.1 to 100 ⁇ m, and more preferably 0.5 to 50 ⁇ m.
  • Examples of the solvent in the dispersion liquid containing one or more compounds selected from the group consisting of Zn, Zr, Hf, and Ti include ion-exchanged water.
  • the dispersion used in the step (a) can be obtained, for example, by adding one or more compounds selected from the group consisting of compounds of Zn, Zr, Hf, and Ti to ion exchange water.
  • the divalent and trivalent metal element chlorides and divalent and trivalent metal element nitrates used in step (a) are used to control the solubility and precipitation rate of the magnesium hydroxide particles of the present invention.
  • chlorides of divalent and trivalent metal elements and nitrates of divalent and trivalent metal elements aluminum chloride, iron chloride, aluminum nitrate, and iron nitrate are preferable.
  • the chlorides of divalent and trivalent metal elements and nitrates of divalent and trivalent metal elements preferably have a purity of 99.0% or more, and more preferably 99.5% or more.
  • the divalent and trivalent metal element chlorides and the divalent and trivalent metal element nitrates preferably have a D 50 of 0.1 to 100 ⁇ m, preferably 0.5 to 50 ⁇ m. More preferred.
  • the organic acid is added to suppress the solubility of the partially hydrated acicular magnesium oxide as a raw material.
  • the organic acid include aliphatic or aromatic organic acids having a carboxyl group, and formic acid, acetic acid, propionic acid, butyric acid, and benzoic acid are preferable.
  • Step (b) is a step of mixing the reaction solution for hydration obtained in step (a) and partially hydrated acicular magnesium oxide particles.
  • the partially hydrated acicular magnesium oxide particles used in the step (b) have a volume cumulative 50% particle diameter (D 50 ) of 0.1 to 10 ⁇ m by laser diffraction scattering type particle size distribution measurement, and a specific surface area. 1.0 to 20.0 m 2 / g, Ig-loss is 2.0 to 25.0%, part of the surface is acicular magnesium oxide hydrated, ie partially hydrated It is acicular magnesium oxide.
  • the hydration rate is fast. Becomes too coarse and becomes agglomerated particles. Further, a D 50 of greater than 10 [mu] m, fully hydrated reaction particles containing magnesium oxide is left not proceed. D 50 is preferably 0.1 to 5.0 ⁇ m.
  • the specific surface area of the partially hydrated acicular magnesium oxide particles used in the step (b) exceeds 20.0 m 2 / g, the hydration rate becomes too fast, resulting in coarse aggregated particles.
  • the specific surface area is less than 1.0 m 2 / g, the hydration reaction does not proceed sufficiently and particles containing magnesium oxide remain.
  • the specific surface area is preferably 2.0 to 18.0 m 2 / g, and more preferably 3.0 to 15.0 m 2 / g.
  • Ig-loss (loss on ignition) showing the total of the moisture content of the partially hydrated acicular magnesium oxide particles used in the step (b) and the moisture content in the hydrate structure is 2.0-25.0% (Mass conversion). That is, Ig-loss indicates the degree of hydration in the partially hydrated acicular magnesium oxide particles in the present invention.
  • the Ig-loss is preferably 2.0 to 20.0%, and preferably 3.0 to 18. More preferably, it is 0%. In the present invention, Ig-loss is determined by measuring partially hydrated acicular magnesium oxide particles after firing at 1000 ° C. for 3600 seconds.
  • the partially hydrated acicular magnesium oxide used in such a step (b) has a volume cumulative 50% particle diameter (D 50 ) of 0.1 to 10 ⁇ m by laser diffraction scattering type particle size distribution measurement, Acicular magnesium oxide particles having a surface area of 1.0-15.0 m 2 / g are obtained by placing them in a thermo-hygrostat at a temperature of 40-95 ° C. and a humidity of 60-95% for 0.5-24 hours. be able to.
  • the Ig-loss of acicular magnesium oxide as a raw material is 0.1 to 1.0%, and the Ig-loss can be increased by increasing the temperature and time placed in the thermo-hygrostat.
  • the D 50 of acicular magnesium oxide used as a raw material for the partially hydrated acicular magnesium oxide used in step (b) is preferably 0.1 to 5.0 ⁇ m.
  • the specific surface area of acicular magnesium oxide, which is a raw material for partially hydrated acicular magnesium oxide prepared in step (b), is preferably 2.0 to 15.0 m 2 / g, 3.0 More preferably, it is ⁇ 15.0 m 2 / g.
  • acicular carbonate prepared by reacting magnesium sulfate and sodium carbonate. Magnesium can be purified and calcined at 1200 ° C.
  • the amount of each component contained in the partially hydrated acicular magnesium oxide used in the step (b) and the dispersion is as follows.
  • the amount of one or more compounds selected from the group consisting of compounds of Zn, Zr, Hf, and Ti is 0.1 to 5.0 mass in terms of metal element with respect to partially hydrated acicular magnesium oxide particles. %.
  • the amount of the compound selected from the group consisting of Zn, Zr, Hf, and Ti is less than 0.1% by mass, when used as a coating agent, the whiteness, ultraviolet absorptivity and refractive index are not sufficient.
  • the particle shape is not a rod-like particle in which the scaly primary particles are aggregated but a hexagonal plate-like particle.
  • the scaly primary particles as in the present invention are not aggregated rod-like particles. Hexagonal columnar particles.
  • the amount of one or more compounds selected from the group consisting of compounds of Zn, Zr, Hf, and Ti is preferably 0.2 to 4.0% by mass with respect to the partially hydrated acicular magnesium oxide particles. More preferably, it is 0.3 to 3.0% by mass.
  • the amount of one or more compounds selected from the group consisting of chlorides of divalent and trivalent metal elements and nitrates of divalent and trivalent metal elements is based on partially hydrated acicular magnesium oxide particles. And 0.1 to 5.0% by mass in terms of metal element. When the addition amount is less than 0.1% by mass, the crystal precipitation rate becomes slow, resulting in monodispersed hexagonal columnar particles, and when the addition amount is more than 5.0% by mass, the crystal precipitation rate becomes too fast and coarse. Agglomerated particles.
  • the amount of one or more compounds selected from the group consisting of chlorides of divalent and trivalent metal elements and nitrates of divalent and trivalent metal elements is based on partially hydrated acicular magnesium oxide particles. In terms of metal element, it is preferably 0.2 to 4.0% by mass, and more preferably 0.3 to 3.0% by mass.
  • the amount of organic acid added is 0.01 to 3.0 mol with respect to 100 g of partially hydrated acicular magnesium oxide particles. 2. When the amount of organic acid added is less than 0.01 mol with respect to 100 g of partially hydrated acicular magnesium oxide particles, the rate of crystal precipitation becomes slow, resulting in monodispersed hexagonal plate or hexagonal columnar particles. If it is larger than 0 mol, the precipitation rate of crystals becomes too fast, resulting in coarse aggregated particles.
  • the amount of the organic acid added is preferably 0.01 to 2.0 mol with respect to 100 g of partially hydrated acicular magnesium oxide.
  • the concentration of the partially hydrated acicular magnesium oxide in the mixed solution is preferably 20 to 200 g / L, more preferably 50 to 180 g / L, and still more preferably 50 to 150 g / L. L. That is, the amount of partially hydrated acicular magnesium oxide in the reaction solution obtained in step (a) is preferably 20 to 200 g / L, more preferably 50 to 180 g / L, and still more preferably 50 to 150 g / L. adjust. If the concentration of partially hydrated acicular magnesium oxide in such a reaction solution is sufficient, the hydration reaction proceeds sufficiently.
  • Step (c) is a step of mixing using a stirrer having a peripheral speed of 7 to 20 m / s at a temperature of 50 to 100 ° C.
  • the number of rotations of stirring is adjusted to control the dispersion state during the reaction.
  • the peripheral speed is less than 7 m / s, rod-shaped magnesium hydroxide in which scaly primary particles are aggregated cannot be obtained.
  • the peripheral speed is higher than 20 m / s, the magnesium hydroxide particles are excessively dispersed at the time of nucleation to form mono-dispersed hexagonal plate or hexagonal columnar magnesium hydroxide particles, and the magnesium hydroxide as in the present invention. Particles cannot be obtained.
  • the apparatus for stirring is not particularly limited as long as the above peripheral speed is satisfied, and examples thereof include homodispers (Primics Co., Ltd., TK homodispers).
  • the peripheral speed is preferably 8 to 18 m / s, more preferably 9 to 15 m / s.
  • the reaction temperature in the step (c) is preferably 55 to 95 ° C, more preferably 60 to 95 ° C.
  • the mixing time can be changed according to the degree of the hydration reaction, and can be, for example, 10 to 360 minutes, preferably 20 to 200 minutes.
  • Step (d) is a step of stirring to obtain a magnesium hydroxide slurry at a temperature of 30 to 100 ° C.
  • the hydration reaction of the unreacted partially hydrated acicular magnesium oxide can be promoted to obtain magnesium hydroxide.
  • the temperature is preferably 50 to 95 ° C, more preferably 70 to 90 ° C.
  • the stirring speed is not particularly limited as long as the magnesium hydroxide slurry can be sufficiently stirred.
  • the stirring speed can be set to 100 to 500 rpm with a three-spring stirrer.
  • the stirring time is not particularly limited as long as the hydration reaction proceeds sufficiently and a desired magnesium hydroxide slurry can be obtained.
  • the stirring time can be 0.5 to 6 hours.
  • Step (e) is a step of obtaining magnesium hydroxide particles by filtering, washing and drying the magnesium hydroxide slurry of step (d). Thereby, the magnesium hydroxide particle of this invention is obtained.
  • the magnesium oxide particles of the present invention are obtained by subjecting the magnesium hydroxide particles of the present invention or the magnesium hydroxide particles obtained by the production method including the steps (a) to (e) of the present invention to 500 to 1400 in an air atmosphere. It is obtained by a method including a step of baking at 0 ° C.
  • the firing of the magnesium hydroxide particles can be performed by firing using an electric furnace or the like.
  • the firing can be achieved by a firing method including a step of raising the temperature to a firing temperature at a predetermined rate of temperature rise and a step of holding at the firing temperature for a predetermined time.
  • the rate of temperature rise is preferably 1 to 20 ° C./min, more preferably 3 to 10 ° C./min.
  • the firing temperature is 500 to 1400 ° C., preferably 600 to 1300 ° C.
  • the firing time which is the time for holding at the firing temperature, is preferably from 0.1 to 5 hours, more preferably from 0.1 to 3 hours.
  • the firing temperature is less than 500 ° C., the amount of heat is insufficient and magnesium hydroxide remains.
  • the firing temperature exceeds 1400 ° C., magnesium oxide grows and does not become rod-shaped magnesium oxide.
  • the shape of the primary particles of magnesium hydroxide particles and magnesium oxide particles obtained by the production method of the present invention is preferably scaly and is the same as the scaly example of FIG.
  • the scaly primary particles of the present invention have a thickness in the range of 0.01 to 0.1 ⁇ m, preferably 0.01 to 0.05 ⁇ m, and the diameter of the circumscribed circle of the surface is 0.2 to 5 ⁇ m, preferably 0. The range is from 5 to 2.5 ⁇ m. More preferably, by the production method of the present invention, rod-shaped magnesium hydroxide particles and magnesium oxide particles in which the flaky primary particles of the present invention are aggregated are obtained.
  • Element mass measurement method Element to be measured in particle (Ag, Al, B, Ba, Bi, Ca, Cd, Co, Cr, Cu, Fe, Ga, Hf, In, K, Li, Mg , Mn, Mo, Na, Ni, P, Pb, Si, Sr, Ti, Tl, V, Zn, and Zr) using an ICP emission analyzer (trade name: SPS-5100, manufactured by Seiko Instruments Inc.) After dissolving the sample in acid, the mass was measured. Using a spectrophotometer (trade name: UV-2550, Shimadzu Corporation), Cl was dissolved in an acid and then mass was measured.
  • ICP emission analyzer trade name: SPS-5100, manufactured by Seiko Instruments Inc.
  • Example 1 Acicular magnesium carbonate prepared by reacting a magnesium sulfate solution and sodium carbonate was fired at a firing temperature of 1200 ° C., and the 50% particle diameter (D 50 ) was 1.12 ⁇ m and the specific surface area was 10 magnesium oxide is .64m 2 / g, the temperature 80 ° C., placed 3 hours in a constant-temperature constant-humidity cabin humidity of 90% of the surface by partially hydrated, specific surface area of 13.46m 2 / g, Ig A partially hydrated acicular magnesium oxide having a loss of 9.08% was obtained.
  • reaction solution was prepared by adding 0.02 mol of propionic acid to 100 g of 100% aluminum chloride hexahydrate and 100 g of partially hydrated acicular magnesium oxide. The temperature of the prepared reaction solution was raised to 60 ° C., and 100 g of magnesium oxide whose surface was partially hydrated was added to obtain a mixed solution.
  • the temperature of the reaction liquid was raised to 95 ° C., and the peripheral speed was adjusted to 9.1 m / s with a stirrer (TK homodisper manufactured by PRIMIX Co., Ltd.) and reacted for 1 hour. Thereafter, a magnesium hydroxide slurry was prepared by stirring at 90 ° C. for 4 hours at a rotation speed at which the slurry could be sufficiently stirred. The produced magnesium hydroxide slurry was filtered, washed with water, and dried to obtain rod-shaped magnesium hydroxide particles of the present invention.
  • TK homodisper manufactured by PRIMIX Co., Ltd.
  • Example 2 It carried out like Example 1 except having used aluminum sulfate instead of aluminum chloride.
  • Example 3 Acicular magnesium oxide is placed in a constant temperature and humidity machine at a temperature of 60 ° C. and a humidity of 90% for 12 hours to partially hydrate the surface, the specific surface area is 10.18 m 2 / g, and the Ig-loss is 21.42%. The procedure was the same as in Example 1 except that.
  • Example 4 Magnesium hydroxide produced in Example 1 was baked in an air atmosphere at 600 ° C. for 1 hour to obtain magnesium oxide particles.
  • Example 5 Magnesium hydroxide produced in Example 1 was baked at 800 ° C. for 1 hour in an air atmosphere to obtain magnesium oxide particles.
  • Example 6 The magnesium hydroxide produced in Example 1 was baked at 1000 ° C. for 1 hour in an air atmosphere to obtain magnesium oxide particles.
  • Example 7 The same procedure as in Example 1 was performed except that propionic acid was changed to acetic acid.
  • Example 8 The same procedure as in Example 1 was performed except that propionic acid was changed to butyric acid.
  • Example 1 The same procedure as in Example 1 was performed except that non-acicular magnesium oxide having a 50% particle size of 1.19 ⁇ m and a specific surface area of 10.82 m 2 / g was used. The Ig-loss of the raw material magnesium oxide was 0.78%.
  • Example 2 The same operation as in Example 1 was performed except that the surface of magnesium oxide was used without being partially hydrated.
  • Example 3 Example 1 except that acicular magnesium oxide was placed in a thermo-hygrostat at a temperature of 80 ° C. and a humidity of 90% for 12 hours, the specific surface area was 8.09 m 2 / g, and the Ig-loss was 26.78%. As well as.
  • [Comparative Example 4] Acicular magnesium oxide is placed in a thermostat at a temperature of 60 ° C. and a humidity of 90% for 3 hours, the specific surface area is 12.41 m 2 / g, the Ig-loss is 11.5%, and the firing temperature is 1500 ° C. The same procedure as in Example 4 was performed except that.
  • Table 1 shows the measurement results regarding the magnesium hydroxide particles and the magnesium oxide particles obtained in the above examples and comparative examples.
  • the magnesium hydroxide particles and the magnesium oxide particles of the present invention are rod-like aggregates of scale-like primary particles, and the 50% particle diameter (D 50 ) is 1.0 to 10
  • the specific surface area was 10 m 2 / g or more.
  • D is a 90 / D 10 is 10 or less, it was confirmed that superior dispersibility.
  • the particles were spherical magnesium hydroxide particles.
  • the magnesium hydroxide particles of Comparative Example 2 had a specific surface area of 8.26 m 2 / g.
  • the magnesium hydroxide particles of Comparative Example 3 were indeterminate in which aggregates of various shapes were mixed, and the specific surface area was 7.45 m 2 / g. Further, the magnesium oxide particles of Comparative Example 4 lost their shape and became irregular when the scale-like magnesium hydroxide was converted to magnesium oxide, and the specific surface area was 6.87 m 2 / g.
  • the method for producing magnesium hydroxide and magnesium oxide of the present invention can easily control the specific surface area by simply hydrating the raw material magnesium oxide with a thermo-hygrostat, etc. Can be manufactured.
  • Magnesium hydroxide particles and magnesium oxide particles of the present invention are rod-shaped, have a small 50% particle size, are uniform, have good dispersibility, and have a high specific surface area, so they are highly useful in various fields. Moreover, since the manufacturing method of this invention can prepare the above magnesium hydroxide and magnesium oxide particle
  • Magnesium hydroxide particles of the present invention include inkjet paper coating agents, flame retardants, heat storage materials, catalysts and electronic materials, etc. Magnesium oxide particles are used as optical materials, inkjet paper coating agents, catalysts and electronic materials. It can be used for applications such as materials.

Abstract

Provided are: a magnesium hydroxide particle and a magnesium oxide particle, each of which has a high specific surface area; and methods respectively for producing the particles. A magnesium hydroxide particle and a magnesium oxide particle, each of which has a rod-like shape formed by the aggregation of scale-like primary particles, also has a volume cumulative 50% particle diameter (D50) of 1.0 to 10.0 μm as measured by a laser diffraction scattering particle size distribution measurement method, and also has a specific surface area of 10 m2/g or more.

Description

高い比表面積を有する棒状の水酸化マグネシウム粒子、及び棒状の酸化マグネシウム粒子、並びにそれらの製造方法Rod-shaped magnesium hydroxide particles having a high specific surface area, rod-shaped magnesium oxide particles, and methods for producing them
　本発明は、高い比表面積を有する棒状の水酸化マグネシウム粒子、及び棒状の酸化マグネシウム粒子、並びにそれらの製造方法に関する。 The present invention relates to rod-shaped magnesium hydroxide particles having a high specific surface area, rod-shaped magnesium oxide particles, and methods for producing them.
　水酸化マグネシウム粒子、及び酸化マグネシウム粒子は、様々な分野で使用されている。水酸化マグネシウム粒子の用途としては、インクジェット用紙のコーティング剤、難燃剤、蓄熱材料、触媒及び電子材料等が挙げられ、酸化マグネシウム粒子の用途としては、光学材料、インクジェット用紙のコーティング剤、触媒及び電子材料等が挙げられる。 Magnesium hydroxide particles and magnesium oxide particles are used in various fields. Applications of magnesium hydroxide particles include inkjet paper coating agents, flame retardants, heat storage materials, catalysts and electronic materials. Magnesium oxide particles applications include optical materials, inkjet paper coating agents, catalysts and electronics. Materials and the like.
　水酸化マグネシウム粒子をインクジェット用紙のコーティング剤、難燃剤、蓄熱材料、触媒及び電子材料用途に用いる場合には、以下のことが望まれている。コーティング剤においては、染料インクが有する多くのＯＨ基と親和性が高いＯＨ基及び多くのマイナス電荷を有する顔料インクに吸着しやすい正電荷を有し、かつ染料が粒子間に染み込みやすい凝集体構造をもつ水酸化マグネシウム粒子が求められている。また、難燃剤、蓄熱材料及び触媒においては、分散性に優れ、高い反応性を示す凝集体構造をもつ水酸化マグネシウム粒子が求められている。さらに、電子材料においては、分散性に優れる小さな水酸化マグネシウム粒子が求められている。 When magnesium hydroxide particles are used for inkjet paper coating agents, flame retardants, heat storage materials, catalysts, and electronic materials, the following are desired. In the coating agent, the aggregate structure has a positive charge that is easy to adsorb on the pigment ink having a high affinity with many OH groups and many negative charges in the dye ink, and the dye can easily penetrate between particles. There is a need for magnesium hydroxide particles having In addition, in the flame retardant, the heat storage material, and the catalyst, magnesium hydroxide particles having an aggregate structure exhibiting excellent dispersibility and high reactivity are demanded. Further, in electronic materials, small magnesium hydroxide particles having excellent dispersibility are required.
　酸化マグネシウム粒子を、光学材料、インクジェット用紙のコーティング剤、触媒及び電子材料等の用途に用いる場合には、以下のことが望まれている。光学材料においては、分散性に優れ、光を拡散しやすい凝集体構造をもつ酸化マグネシウム粒子が求められている。また、触媒においては、分散性に優れ、高い反応性を示す凝集体構造をもつ酸化マグネシウム粒子が求められている。さらに、電子材料においては、分散性に優れる小さな酸化マグネシウム粒子が求められている。 When magnesium oxide particles are used in applications such as optical materials, inkjet paper coating agents, catalysts, and electronic materials, the following are desired. In optical materials, there is a demand for magnesium oxide particles having an aggregate structure that is excellent in dispersibility and easily diffuses light. In addition, as a catalyst, magnesium oxide particles having an aggregate structure that has excellent dispersibility and high reactivity are required. Furthermore, small magnesium oxide particles having excellent dispersibility are required for electronic materials.
　特許文献１には、硫酸イオン〔（ＳＯ４）２－〕／マグネシウムイオン〔（Ｍｇ）２＋〕のイオン濃度比を、０．３～２．０の範囲にすることにより得られる、２以上の異方向のリーフレット状片が結合および／または交叉した構造を有する球状の水酸化マグネシウム粒子が記載されている。しかし、特許文献１に記載の方法では安定して球状の水酸化マグネシウムができず、板状、及び柱状の水酸化マグネシウムが混在してしまい、このような水酸化マグネシウム粒子は、樹脂等に対する分散性が十分ではなく、触媒等に使用した場合は比表面積が低く反応性が低いという問題があった。 Patent Document 1 discloses that the ion concentration ratio of sulfate ion [(SO 4 ) 2− ] / magnesium ion [(Mg) 2+ ] is in the range of 0.3 to 2.0. Spherical magnesium hydroxide particles having a structure in which leaflets in different directions are joined and / or crossed are described. However, the method described in Patent Document 1 cannot stably form spherical magnesium hydroxide, and plate-like and columnar magnesium hydroxide are mixed, and such magnesium hydroxide particles are dispersed in a resin or the like. When used as a catalyst or the like, there is a problem that the specific surface area is low and the reactivity is low.
特開２００３－２６１７９６号公報JP 2003-26196A
　本発明は、高い比表面積を有する水酸化マグネシウム粒子及び酸化マグネシウム粒子、並びにそれらの製造方法を提供することを目的とする。 An object of the present invention is to provide magnesium hydroxide particles and magnesium oxide particles having a high specific surface area, and methods for producing them.
　本発明者は、Ｚｎ、Ｚｒ、Ｈｆ、及びＴｉの化合物からなる群より選択される１以上の化合物を含む分散液に、２価及び３価の金属元素の塩化物、並びに２価及び３価の金属元素の硝酸塩からなる群より選択される１以上の化合物（ただし、Ｚｎ、Ｚｒ、Ｈｆ、及びＴｉの化合物は除く）を添加し、さらに有機酸を添加して得られる反応液と、恒温恒湿機等で、針状の酸化マグネシウム粒子の表面を部分的に水和させた針状の酸化マグネシウム粒子とを混合して、高せん断下で水和反応させることにより、分散性に優れ、反応性の高い、高い比表面積を有する水酸化マグネシウム粒子が得られることを見出した。また、本発明者らは、本発明の水酸化マグネシウム粒子を、大気雰囲気中で５００℃～１４００℃で焼成することで、高い比表面積を有する酸化マグネシウム粒子が得られることを見出した。 The inventor has added divalent and trivalent metal element chlorides, divalent and trivalent to a dispersion containing one or more compounds selected from the group consisting of Zn, Zr, Hf, and Ti. A reaction solution obtained by adding one or more compounds selected from the group consisting of nitrates of metal elements (excluding Zn, Zr, Hf, and Ti compounds) and further adding an organic acid; and a constant temperature Mixing with acicular magnesium oxide particles partially hydrated the surface of acicular magnesium oxide particles with a humidity controller etc., and by hydration reaction under high shear, excellent dispersibility, It has been found that highly reactive magnesium hydroxide particles having a high specific surface area can be obtained. Further, the present inventors have found that magnesium oxide particles having a high specific surface area can be obtained by firing the magnesium hydroxide particles of the present invention at 500 ° C. to 1400 ° C. in an air atmosphere.
　すなわち、本発明は、鱗片状の一次粒子が凝集した棒状であり、レーザ回折散乱式粒度分布測定による体積累積の５０％粒子径（Ｄ５０）が１．０～１０．０μｍであり、比表面積が１０ｍ２／ｇ以上である、水酸化マグネシウム粒子に関する。
　本発明は、さらに、Ｚｎ、Ｚｒ、Ｈｆ、及びＴｉからなる群より選択される１以上の金属元素を金属元素換算で０．１～５．０質量％含み、２価及び３価の金属元素からなる群より選択される１以上の更なる金属元素（ただし、Ｚｎ、Ｚｒ、Ｈｆ、及びＴｉは除く）を金属元素換算で０．１～５．０質量％含む、前記に記載の水酸化マグネシウム粒子に関する。
　本発明は、鱗片状の一次粒子が凝集した棒状であり、レーザ回折散乱式粒度分布測定による体積累積の５０％粒子径（Ｄ５０）が１．０～１０．０μｍであり、比表面積が１０ｍ２／ｇ以上である、酸化マグネシウム粒子に関する。
　本発明は、さらに、Ｚｎ、Ｚｒ、Ｈｆ、及びＴｉからなる群より選択される１以上の金属元素を金属元素換算で０．１～５．０質量％含み、２価及び３価の金属元素からなる群より選択される１以上の更なる金属元素（ただし、Ｚｎ、Ｚｒ、Ｈｆ、及びＴｉは除く）を金属元素換算で０．１～５．０質量％含む、前記に記載の酸化マグネシウム粒子に関する。
　本発明は、水酸化マグネシウム粒子の製造方法であって、
（ａ）Ｚｎ、Ｚｒ、Ｈｆ、及びＴｉの化合物からなる群より選択される１以上の化合物を含む分散液に、２価及び３価の金属元素の塩化物、並びに２価及び３価の金属元素の硝酸塩からなる群より選択される１以上の化合物（ただし、Ｚｎ、Ｚｒ，Ｈｆ、及びＴｉの化合物は除く）を添加し、さらに、有機酸を添加して反応液を得る工程、
（ｂ）工程（ａ）の反応液、及びレーザ回折散乱式粒度分布測定による体積累積の５０％粒子径（Ｄ５０）が０．１～１０μｍであり、比表面積が１．０～２０．０ｍ２／ｇであり、Ｉｇ－ｌｏｓｓが２．０～２５．０％である、一部水和針状酸化マグネシウムを混合して、混合液を得る工程
（ここで、
　Ｚｎ、Ｚｒ、Ｈｆ、及びＴｉの化合物からなる群より選択される１以上の化合物は、一部水和針状酸化マグネシウムに対して、金属元素換算で０．１～５．０質量％であり、
　２価及び３価の金属元素の塩化物、並びに２価及び３価の金属元素の硝酸塩からなる群より選択される１以上の化合物は、一部水和針状酸化マグネシウムに対して、金属元素換算で０．１～５．０質量％であり、
　有機酸は、一部水和針状酸化マグネシウム１００ｇに対し、０．０１～３．０ｍｏｌである）、
（ｃ）工程（ｂ）の混合液を５０～１００℃の温度で、周速が７～２０ｍ／ｓである撹拌機を用いて混合する工程、
（ｄ）３０～１００℃の温度で、撹拌して水酸化マグネシウムスラリーを得る工程、及び
（ｅ）工程（ｄ）の水酸化マグネシウムスラリーをろ過、水洗、乾燥させて、水酸化マグネシウム粒子を得る工程
を含む、水酸化マグネシウム粒子の製造方法に関する。
　本発明は、工程（ｂ）の一部水和針状酸化マグネシウムが、レーザ回折散乱式粒度分布測定による体積累積の５０％粒子径（Ｄ５０）が０．１～１０μｍであり、比表面積が１．０～１５．０ｍ２／ｇである針状酸化マグネシウム粒子を、温度４０～９５℃、湿度６０～９５％の恒温恒湿機内に、０．５～２４時間置くことにより得られる、前記に記載の方法に関する。
　本発明は、工程（ｂ）の混合液における、一部水和針状酸化マグネシウムの濃度が２０～２００ｇ／Ｌである、前記に記載の方法に関する。
　本発明は、酸化マグネシウム粒子の製造方法であって、前記に記載の水酸化マグネシウム粒子或いは前記に記載の方法により得られる水酸化マグネシウム粒子を、大気雰囲気中で、５００～１４００℃で焼成する工程を含む、酸化マグネシウム粒子の製造方法に関する。 That is, the present invention is a rod-like aggregate of scaly primary particles, the volume cumulative 50% particle diameter (D 50 ) measured by laser diffraction / scattering particle size distribution measurement is 1.0 to 10.0 μm, and the specific surface area Relates to magnesium hydroxide particles having a particle size of 10 m 2 / g or more.
The present invention further includes one or more metal elements selected from the group consisting of Zn, Zr, Hf, and Ti in an amount of 0.1 to 5.0% by mass in terms of metal elements, and bivalent and trivalent metal elements The hydroxide according to the above, containing 0.1 to 5.0% by mass of one or more additional metal elements selected from the group consisting of Zn (excluding Zn, Zr, Hf, and Ti) in terms of metal elements It relates to magnesium particles.
The present invention is a rod shape in which scaly primary particles are aggregated, the volume cumulative 50% particle diameter (D 50 ) measured by laser diffraction scattering type particle size distribution is 1.0 to 10.0 μm, and the specific surface area is 10 m. It is related with the magnesium oxide particle which is 2 / g or more.
The present invention further includes one or more metal elements selected from the group consisting of Zn, Zr, Hf, and Ti in an amount of 0.1 to 5.0% by mass in terms of metal elements, and bivalent and trivalent metal elements Magnesium oxide according to the above, comprising 0.1 to 5.0% by mass in terms of metal element of one or more additional metal elements selected from the group consisting of (except for Zn, Zr, Hf, and Ti) Concerning particles.
The present invention is a method for producing magnesium hydroxide particles,
(A) In a dispersion containing one or more compounds selected from the group consisting of Zn, Zr, Hf, and Ti, divalent and trivalent metal element chlorides, and divalent and trivalent metals Adding one or more compounds selected from the group consisting of elemental nitrates (excluding Zn, Zr, Hf, and Ti compounds), and further adding an organic acid to obtain a reaction solution;
(B) The reaction liquid in step (a) and the volume cumulative 50% particle diameter (D 50 ) measured by laser diffraction / scattering particle size distribution measurement are 0.1 to 10 μm, and the specific surface area is 1.0 to 20.0 m. 2 / g and Ig-loss is 2.0 to 25.0%, a partially hydrated acicular magnesium oxide is mixed to obtain a mixture (where,
One or more compounds selected from the group consisting of compounds of Zn, Zr, Hf, and Ti are 0.1 to 5.0% by mass in terms of metal elements with respect to partially hydrated acicular magnesium oxide. ,
One or more compounds selected from the group consisting of divalent and trivalent metal element chlorides, and divalent and trivalent metal element nitrates are partially hydrated with acicular magnesium oxide. 0.1 to 5.0 mass% in terms of conversion,
The organic acid is 0.01 to 3.0 mol with respect to 100 g of partially hydrated acicular magnesium oxide)
(C) mixing the liquid mixture of step (b) at a temperature of 50 to 100 ° C. using a stirrer having a peripheral speed of 7 to 20 m / s,
(D) a step of obtaining a magnesium hydroxide slurry by stirring at a temperature of 30 to 100 ° C., and (e) filtering, washing with water and drying the magnesium hydroxide slurry of step (d) to obtain magnesium hydroxide particles. The present invention relates to a method for producing magnesium hydroxide particles, including a step.
In the present invention, the partially hydrated acicular magnesium oxide in the step (b) has a volume cumulative 50% particle diameter (D 50 ) of 0.1 to 10 μm by laser diffraction scattering type particle size distribution measurement, and has a specific surface area of Obtained by placing acicular magnesium oxide particles of 1.0 to 15.0 m 2 / g in a thermo-hygrostat at a temperature of 40 to 95 ° C. and a humidity of 60 to 95% for 0.5 to 24 hours, Relates to the method described in.
The present invention relates to the method as described above, wherein the concentration of the partially hydrated acicular magnesium oxide in the mixed solution of step (b) is 20 to 200 g / L.
The present invention is a method for producing magnesium oxide particles, the step of firing the magnesium hydroxide particles described above or the magnesium hydroxide particles obtained by the method described above at 500 to 1400 ° C. in an air atmosphere. The manufacturing method of a magnesium oxide particle containing this.
　本発明により、高い比表面積を有する鱗片状の一次粒子が凝集した棒状の水酸化マグネシウム粒子及び酸化マグネシウム粒子、並びにそれらの製造方法が提供される。本発明の水酸化マグネシウム粒子及び酸化マグネシウム粒子は、高い比表面積、及び分散性を有し、様々な分野に有用である。また、本発明の製造方法によれば、高い比表面積、及び分散性を有する水酸化マグネシウム粒子及び酸化マグネシウム粒子を容易に製造することができる。 The present invention provides rod-shaped magnesium hydroxide particles and magnesium oxide particles in which scaly primary particles having a high specific surface area are aggregated, and methods for producing them. The magnesium hydroxide particles and magnesium oxide particles of the present invention have a high specific surface area and dispersibility, and are useful in various fields. Moreover, according to the manufacturing method of this invention, the magnesium hydroxide particle and magnesium oxide particle which have a high specific surface area and a dispersibility can be manufactured easily.
本発明の水酸化マグネシウム粒子の電子顕微鏡写真である。鱗片状の一次粒子の一例を白丸で囲んだ。It is an electron micrograph of the magnesium hydroxide particle of this invention. An example of scaly primary particles is surrounded by white circles.
　本発明の水酸化マグネシウム粒子は、鱗片状の一次粒子が凝集した棒状であり、レーザ回折散乱式粒度分布測定による体積累積の５０％粒子径（Ｄ５０）が１．０～１０．０μｍであり、比表面積が１０ｍ２／ｇ以上である。 The magnesium hydroxide particles of the present invention are rod-like aggregates of scaly primary particles, and the volume cumulative 50% particle diameter (D 50 ) measured by laser diffraction scattering type particle size distribution is 1.0 to 10.0 μm. The specific surface area is 10 m 2 / g or more.
　本発明の一次粒子の形状は、鱗片状である。鱗片状の一例を、図１において示す。本発明の鱗片状の一次粒子は、厚みが０．０１～０．１μｍ、好ましくは０．０１～０．０５μｍの範囲であり、面の外接円の直径が０．２～５μｍ、好ましくは０．５～２．５μｍの範囲である。 The shape of the primary particles of the present invention is scaly. An example of a scale-like shape is shown in FIG. The scaly primary particles of the present invention have a thickness in the range of 0.01 to 0.1 μm, preferably 0.01 to 0.05 μm, and the diameter of the circumscribed circle of the surface is 0.2 to 5 μm, preferably 0. The range is from 5 to 2.5 μm.
　なお、本明細書中、棒状とは、鱗片状の一次粒子が凝集した粒子でアスペクト比（粒子長さＬ／粒子断面径Ｄ）が１．５～２０、好ましくは２～１０の範囲にある粒子のことをいう。ここで、棒状の場合、具体的にはＬは１～１０μｍ、Ｄは０．１～５μｍの範囲である。また、針状とは、アスペクト比（粒子長さＬ／粒子断面径Ｄ）が２１～１０００、好ましくは５０～５００の範囲にある粒子のことをいう。ここで、針状の場合、具体的にはＬは０．１～１０μｍ、Ｄは具体的には０．００１～０．５μｍの範囲である。また、球状とは、鱗辺状の一次粒子が凝集した球形状であってアスペクト比（粒子長さＬ／粒子断面径Ｄ）が１．０～１．２の範囲にある粒子のことをいう。ここで、球状の場合、Ｌは具体的には１～２０μｍ、Ｄは具体的には１～２０μｍの範囲である。 In the present specification, a rod-like particle is a particle in which scaly primary particles are aggregated and has an aspect ratio (particle length L / particle cross-sectional diameter D) of 1.5 to 20, preferably 2 to 10. Refers to particles. Here, in the case of a rod shape, specifically, L is in the range of 1 to 10 μm and D is in the range of 0.1 to 5 μm. The needle shape refers to particles having an aspect ratio (particle length L / particle cross-sectional diameter D) of 21 to 1000, preferably 50 to 500. Here, in the case of a needle shape, specifically, L is in the range of 0.1 to 10 μm, and D is specifically in the range of 0.001 to 0.5 μm. The spherical shape refers to particles having a spherical shape in which the primary particles of the scales are aggregated and having an aspect ratio (particle length L / particle cross-sectional diameter D) in the range of 1.0 to 1.2. . Here, in the case of a spherical shape, L is specifically in the range of 1 to 20 μm, and D is specifically in the range of 1 to 20 μm.
　このような一次粒子が凝集した棒状の粒子は、均一な細孔が粒子表面に存在し、従来の製造方法により得られる六角板状の水酸化マグネシウム粒子（特開２００６－３０６６５８号公報参照）に比べて、比表面積が高いことから液体及び気体分子の吸着性が高い。また、このような一次粒子が凝集した棒状の粒子を用紙のコーティング剤として使用した場合、棒状の粒子を構成している鱗片状の水酸化マグネシウムが密集しすぎないため、インクの吸着性が良好である。 Such rod-like particles in which primary particles are aggregated have uniform pores on the particle surface, and hexagonal plate-like magnesium hydroxide particles obtained by a conventional production method (see JP 2006-306658 A). Compared with the high specific surface area, the adsorptivity of liquid and gas molecules is high. In addition, when such rod-shaped particles in which primary particles are aggregated are used as a coating agent for paper, the scale-like magnesium hydroxide constituting the rod-shaped particles is not too dense, and thus the ink adsorption is good. It is.
　本発明の水酸化マグネシウム粒子は、鱗片状の一次粒子が凝集した棒状であり、レーザ回折散乱式粒度分布測定による体積累積の５０％粒子径（Ｄ５０）が１．０～１０．０μｍであり、比表面積が１０ｍ２／ｇ以上である。このような範囲であれば、樹脂等への配合時に粘度が高くなりすぎず、また粒子の凝集が抑えられるため分散性が良好である。また、このような粒子径を有する水酸化マグネシウム粒子を用紙のコーティング剤として使用した場合には、インクの定着性及び吸収性が良好である。さらに、粒子径が大きすぎないため光学材料及び電子材料に有用である。本発明の水酸化マグネシウム粒子のレーザ回折散乱式粒度分布測定による体積累積の５０％粒子径（Ｄ５０）は、好ましくは２．０～９．０μｍであり、より好ましくは３．０～８．０μｍであり、比表面積は、好ましくは１０～２００ｍ２／ｇであり、より好ましくは２０～１５０ｍ２／ｇである。本発明において、比表面積はＢＥＴ法により求められる。 The magnesium hydroxide particles of the present invention are rod-like aggregates of scaly primary particles, and the volume cumulative 50% particle diameter (D 50 ) measured by laser diffraction scattering type particle size distribution is 1.0 to 10.0 μm. The specific surface area is 10 m 2 / g or more. Within such a range, the viscosity does not become too high when blended with a resin or the like, and the agglomeration of particles is suppressed, so that the dispersibility is good. In addition, when the magnesium hydroxide particles having such a particle size are used as a paper coating agent, the ink fixing and absorbing properties are good. Furthermore, since the particle diameter is not too large, it is useful for optical materials and electronic materials. The volume cumulative 50% particle diameter (D 50 ) of the magnesium hydroxide particles of the present invention as measured by laser diffraction scattering type particle size distribution is preferably 2.0 to 9.0 μm, more preferably 3.0 to 8. The specific surface area is preferably 10 to 200 m 2 / g, more preferably 20 to 150 m 2 / g. In the present invention, the specific surface area is determined by the BET method.
　本発明の水酸化マグネシウム粒子は、レーザ回折散乱式粒度分布測定による体積基準の累積１０％粒子径（Ｄ１０）と累積９０％粒子径（Ｄ９０）との比Ｄ９０／Ｄ１０が、好ましくは１０以下、より好ましくは１～８の範囲である。このような比Ｄ９０／Ｄ１０であれば、水酸化マグネシウム粒子の粒度分布が狭く、粒子の凝集が少ないので、さらに優れた分散性が得られる。 The magnesium hydroxide particles of the present invention preferably have a ratio D 90 / D 10 of the volume-based cumulative 10% particle diameter (D 10 ) and cumulative 90% particle diameter (D 90 ) by laser diffraction scattering particle size distribution measurement. Is 10 or less, more preferably in the range of 1-8. With such a ratio D 90 / D 10, narrow particle size distribution of the magnesium hydroxide particles, since aggregation of particles is small, it can be obtained more excellent dispersibility.
　本発明の水酸化マグネシウム粒子は、その製造工程において使用される化合物の金属元素をさらに含んでいてもよい。本発明の水酸化マグネシウム粒子は、Ｚｎ、Ｚｒ、Ｈｆ、及びＴｉからなる群より選択される１以上の金属元素を、金属元素換算で０．１～５．０質量％含み、さらに２価及び３価の金属元素からなる群より選択される１以上の更なる金属元素（ただし、Ｚｎ、Ｚｒ、Ｈｆ、及びＴｉは除く）を、金属元素換算で０．１～５．０質量％含むことができる。これらの金属元素の含有量であれば、水酸化マグネシウム粒子をコーティング剤として使用した場合に、白色度、紫外線吸収性、及び屈折率等が十分である。Ｚｎ、Ｚｒ、Ｈｆ、及びＴｉからなる群より選択される１以上の金属元素、つまりＺｎ、Ｚｒ、Ｈｆ、Ｔｉ、又はそれらの混合物の含有量は、金属元素換算で、好ましくは０．２～４．０質量％であり、より好ましくは０．３～３．０質量％である。 The magnesium hydroxide particles of the present invention may further contain a metal element of a compound used in the production process. The magnesium hydroxide particles of the present invention contain one or more metal elements selected from the group consisting of Zn, Zr, Hf, and Ti in an amount of 0.1 to 5.0% by mass in terms of metal elements, and are divalent and Containing 0.1 to 5.0% by mass of one or more additional metal elements selected from the group consisting of trivalent metal elements (excluding Zn, Zr, Hf, and Ti) in terms of metal elements Can do. With these metal element contents, whiteness, ultraviolet absorption, refractive index, and the like are sufficient when magnesium hydroxide particles are used as the coating agent. The content of one or more metal elements selected from the group consisting of Zn, Zr, Hf, and Ti, that is, Zn, Zr, Hf, Ti, or a mixture thereof is preferably 0.2 to It is 4.0% by mass, and more preferably 0.3 to 3.0% by mass.
　本発明において、２価及び３価の金属元素からなる群より選択される１以上の更なる金属元素（ただし、Ｚｎ、Ｚｒ、Ｈｆ、及びＴｉは除く）としては、特に限定されず、Ａｇ、Ａｌ、Ｂ、Ｂａ、Ｂｉ、Ｃａ、Ｃｄ、Ｃｏ、Ｃｒ、Ｃｕ、Ｆｅ、Ｇａ、Ｉｎ、Ｍｎ、Ｍｏ、Ｎｉ、Ｐｂ、Ｓｒ、Ｔｌ、及びＶが挙げられ、Ａｌ及びＦｅが好ましい。２価及び３価の金属元素からなる群より選択される１以上の更なる金属元素（ただし、Ｚｎ、Ｚｒ、Ｈｆ、及びＴｉは除く）の含有量は、金属元素換算で、０．１～５．０質量％であり、好ましくは０．２～４．０質量％であり、より好ましくは０．３～３．０質量％である。 In the present invention, one or more additional metal elements selected from the group consisting of divalent and trivalent metal elements (excluding Zn, Zr, Hf, and Ti) are not particularly limited, and Ag, Examples include Al, B, Ba, Bi, Ca, Cd, Co, Cr, Cu, Fe, Ga, In, Mn, Mo, Ni, Pb, Sr, Tl, and V, and Al and Fe are preferable. The content of one or more additional metal elements selected from the group consisting of divalent and trivalent metal elements (excluding Zn, Zr, Hf, and Ti) is 0.1 to The amount is 5.0% by mass, preferably 0.2 to 4.0% by mass, and more preferably 0.3 to 3.0% by mass.
　本発明の酸化マグネシウム粒子は、鱗片状の一次粒子が凝集した棒状であり、レーザ回折散乱式粒度分布測定による体積累積の５０％粒子径（Ｄ５０）が１．０～１０．０μｍであり、比表面積が１０ｍ２／ｇ以上である。本発明の一次粒子の形状は、鱗片状であり、図１の鱗片状の一例と同様である。本発明の鱗片状の一次粒子は、厚みが０．０１～０．１μｍ、好ましくは０．０１～０．０５μｍの範囲であり、面の外接円の直径が０．２～５μｍ、好ましくは０．５～２．５μｍの範囲である。このような酸化マグネシウム粒子は、樹脂等への分散性が優れている。具体的には、このような粒子径及び比表面積を有する酸化マグネシウム粒子は、用紙のコーティング剤として使用した場合、インクの定着性及び吸収性が良好である。また樹脂等への配合時に粘度が高くなりすぎず、粒子の凝集が抑えられるため分散性が良好である。さらに、粒子径が大きすぎないため光学材料及び電子材料に有用である。本発明の酸化マグネシウム粒子のレーザ回折散乱式粒度分布測定による体積累積の５０％粒子径（Ｄ５０）は、好ましくは２．０～９．０μｍであり、より好ましくは３．０～８．０μｍであり、比表面積は、好ましくは１０～２００ｍ２／ｇであり、より好ましくは２０～１５０ｍ２／ｇである。 The magnesium oxide particles of the present invention are rod-like aggregates of scaly primary particles, and the 50% particle diameter (D 50 ) of volume accumulation by laser diffraction scattering type particle size distribution measurement is 1.0 to 10.0 μm, The specific surface area is 10 m 2 / g or more. The shape of the primary particles of the present invention is scaly and is similar to the scaly example of FIG. The scaly primary particles of the present invention have a thickness in the range of 0.01 to 0.1 μm, preferably 0.01 to 0.05 μm, and the diameter of the circumscribed circle of the surface is 0.2 to 5 μm, preferably 0. The range is from 5 to 2.5 μm. Such magnesium oxide particles have excellent dispersibility in a resin or the like. Specifically, magnesium oxide particles having such a particle size and specific surface area have good ink fixability and absorbability when used as a paper coating agent. In addition, the viscosity does not become too high when blended with a resin or the like, and the agglomeration of particles is suppressed, so that the dispersibility is good. Furthermore, since the particle diameter is not too large, it is useful for optical materials and electronic materials. The volume cumulative 50% particle diameter (D 50 ) of the magnesium oxide particles of the present invention as measured by laser diffraction scattering type particle size distribution is preferably 2.0 to 9.0 μm, more preferably 3.0 to 8.0 μm. The specific surface area is preferably 10 to 200 m 2 / g, more preferably 20 to 150 m 2 / g.
　本発明の酸化マグネシウム粒子は、レーザ回折散乱式粒度分布測定による体積基準の累積１０％粒子径（Ｄ１０）と累積９０％粒子径（Ｄ９０）との比Ｄ９０／Ｄ１０が、好ましくは１０以下であり、より好ましくは１～８の範囲である。このような比Ｄ９０／Ｄ１０であれば、酸化マグネシウム粒子の粒度分布が狭く、粒子の凝集が少ないので、さらに優れた分散性を得ることができる。 The magnesium oxide particles of the present invention preferably have a ratio D 90 / D 10 of a volume-based cumulative 10% particle diameter (D 10 ) and cumulative 90% particle diameter (D 90 ) by laser diffraction scattering particle size distribution measurement. It is 10 or less, and more preferably in the range of 1-8. With such a ratio D 90 / D 10 , the particle size distribution of the magnesium oxide particles is narrow and the particles are less aggregated, so that further excellent dispersibility can be obtained.
　本発明の酸化マグネシウム粒子は、その製造工程において使用される化合物の金属元素をさらに含んでいてもよい。本発明の酸化マグネシウム粒子は、Ｚｎ、Ｚｒ、Ｈｆ、及びＴｉからなる群より選択される１以上の金属元素を、金属元素換算で０．１～５．０質量％含み、さらに２価及び３価の金属元素からなる群より選択される１以上の更なる金属元素（ただし、Ｚｎ、Ｚｒ、Ｈｆ、及びＴｉは除く）を、金属元素換算で０．１～５．０質量％含むことができる。これらのような金属元素の含有量であれば、酸化マグネシウム粒子をコーティング剤として使用した場合に、白色度、紫外線吸収性及び屈折率等が十分である。Ｚｎ、Ｚｒ、Ｈｆ、及びＴｉからなる群より選択される１以上の金属元素、つまりＺｎ、Ｚｒ、Ｈｆ、Ｔｉ、又はそれらの混合物の含有量は、金属元素換算で、好ましくは０．２～４．０質量％であり、より好ましくは０．３～３．０質量％である。 The magnesium oxide particles of the present invention may further contain a metal element of a compound used in the production process. The magnesium oxide particles of the present invention contain one or more metal elements selected from the group consisting of Zn, Zr, Hf, and Ti in an amount of 0.1 to 5.0% by mass in terms of metal elements, and are further divalent and 3 One or more additional metal elements selected from the group consisting of valent metal elements (excluding Zn, Zr, Hf, and Ti) may be contained in an amount of 0.1 to 5.0% by mass in terms of metal elements it can. With these metal element contents, whiteness, ultraviolet absorptivity, refractive index, etc. are sufficient when magnesium oxide particles are used as a coating agent. The content of one or more metal elements selected from the group consisting of Zn, Zr, Hf, and Ti, that is, Zn, Zr, Hf, Ti, or a mixture thereof is preferably 0.2 to It is 4.0% by mass, and more preferably 0.3 to 3.0% by mass.
　２価及び３価の金属元素からなる群より選択される１以上の更なる金属元素（ただし、Ｚｎ、Ｚｒ、Ｈｆ、及びＴｉは除く）としては、特に限定されず、Ａｇ、Ａｌ、Ｂ、Ｂａ、Ｂｉ、Ｃｄ、Ｃｏ、Ｃｒ、Ｃｕ、Ｆｅ、Ｇａ、Ｉｎ、Ｍｎ、Ｍｏ、Ｎｉ、Ｐｂ、Ｓｒ、Ｔｌ、及びＶが挙げられ、Ａｌ及びＦｅが好ましい。２価及び３価の金属元素からなる群より選択される１以上の更なる金属元素（ただし、Ｚｎ、Ｚｒ、Ｈｆ、及びＴｉは除く）の含有量は、金属元素換算で、好ましくは０．２～４．０質量％であり、より好ましくは０．３～３．０質量％である。 One or more additional metal elements selected from the group consisting of divalent and trivalent metal elements (excluding Zn, Zr, Hf, and Ti) are not particularly limited, and Ag, Al, B, Examples include Ba, Bi, Cd, Co, Cr, Cu, Fe, Ga, In, Mn, Mo, Ni, Pb, Sr, Tl, and V, and Al and Fe are preferable. The content of one or more additional metal elements selected from the group consisting of divalent and trivalent metal elements (excluding Zn, Zr, Hf, and Ti) is preferably 0.00 in terms of metal elements. It is 2 to 4.0% by mass, and more preferably 0.3 to 3.0% by mass.
　本発明の水酸化マグネシウム粒子の製造方法は、
（ａ）Ｚｎ、Ｚｒ、Ｈｆ、及びＴｉの化合物からなる群より選択される１以上の化合物を含む分散液に、２価及び３価の金属元素の塩化物、並びに２価及び３価の金属元素の硝酸塩からなる群より選択される１以上の化合物（ただし、Ｚｎ、Ｚｒ、Ｈｆ、及びＴｉの化合物は除く）を添加し、さらに、有機酸を添加して反応液を得る工程、
（ｂ）工程（ａ）の反応液、及びレーザ回折散乱式粒度分布測定による体積累積の５０％粒子径（Ｄ５０）が０．１～１０μｍであり、比表面積が１．０～２０．０ｍ２／ｇであり、Ｉｇ－ｌｏｓｓが２．０～２５．０％である、一部水和針状酸化マグネシウムを混合して、混合液を得る工程、
（ここで、
　Ｚｎ、Ｚｒ、Ｈｆ、及びＴｉの化合物からなる群より選択される１以上の化合物は、一部水和針状酸化マグネシウムに対して、金属元素換算で０．１～５．０質量％であり、
　２価及び３価の金属元素の塩化物、及び２価及び３価の金属元素の硝酸塩からなる群より選択される１以上の化合物は、一部水和針状酸化マグネシウムに対して、金属元素換算で０．１～５．０質量％であり、
　有機酸は、一部水和針状酸化マグネシウム１００ｇに対して、０．０１～３．０ｍｏｌである）、
（ｃ）工程（ｂ）の混合液を、５０～１００℃の温度で、周速が７～２０ｍ／ｓである撹拌機を用いて、混合する工程、
（ｄ）３０～１００℃の温度で、撹拌して水酸化マグネシウムスラリーを得る工程、及び（ｅ）工程（ｄ）の水酸化マグネシウムスラリーをろ過、水洗、乾燥させて、水酸化マグネシウム粒子を得る工程
を含む。 The method for producing magnesium hydroxide particles of the present invention comprises:
(A) In a dispersion containing one or more compounds selected from the group consisting of Zn, Zr, Hf, and Ti, divalent and trivalent metal element chlorides, and divalent and trivalent metals Adding one or more compounds selected from the group consisting of elemental nitrates (excluding Zn, Zr, Hf, and Ti compounds), and further adding an organic acid to obtain a reaction solution;
(B) The reaction liquid in step (a) and the volume cumulative 50% particle diameter (D 50 ) measured by laser diffraction / scattering particle size distribution measurement are 0.1 to 10 μm, and the specific surface area is 1.0 to 20.0 m. 2 / g, Ig-loss is 2.0 to 25.0%, mixing partially hydrated acicular magnesium oxide to obtain a mixture,
(here,
One or more compounds selected from the group consisting of compounds of Zn, Zr, Hf, and Ti are 0.1 to 5.0% by mass in terms of metal elements with respect to partially hydrated acicular magnesium oxide. ,
One or more compounds selected from the group consisting of divalent and trivalent metal element chlorides and divalent and trivalent metal element nitrates are partially hydrated with acicular magnesium oxide. 0.1 to 5.0 mass% in terms of conversion,
The organic acid is 0.01 to 3.0 mol with respect to 100 g of partially hydrated acicular magnesium oxide),
(C) a step of mixing the mixed liquid of step (b) using a stirrer having a peripheral speed of 7 to 20 m / s at a temperature of 50 to 100 ° C .;
(D) a step of obtaining a magnesium hydroxide slurry by stirring at a temperature of 30 to 100 ° C., and (e) filtering, washing with water and drying the magnesium hydroxide slurry of step (d) to obtain magnesium hydroxide particles. Process.
　工程（ａ）は、一部水酸化マグネシウムの水和反応のための反応液を得る工程である。
　Ｚｎ、Ｚｒ、Ｈｆ、及びＴｉの化合物からなる群より選択される１以上の化合物は、本発明の水酸化マグネシウム粒子及び酸化マグネシウム粒子を作成するために添加される。これにより、白色度、紫外線吸収性及び屈折率等が向上し、光学材料や、インクジェット用紙のコーティング剤に適する本発明の水酸化マグネシウム及び酸化マグネシウム粒子が得られる。
　Ｚｎ、Ｚｒ、Ｈｆ、及びＴｉの化合物として、これらの金属元素を有する化合物であれば特に限定されず、酸化物、水酸化物、水素化物、ハロゲン化物（フッ化物、塩化物、臭化物、及びヨウ化物）、リン酸塩、炭酸塩、及び硝酸塩などが挙げられ、酸化亜鉛、水酸化亜鉛、塩化亜鉛、硝酸亜鉛、酸化ジルコニウム、水酸化ジルコニウム、塩化ジルコニウム、硝酸ジルコニウム、酸化ハフニウム、水酸化ハフニウム、塩化ハフニウム、硝酸ハフニウム、酸化チタン、水酸化チタン、塩化チタン、及び硝酸チタンが好ましい。
　Ｚｎ、Ｚｒ、Ｈｆ、及びＴｉの化合物は、純度が９９．０％以上であることが好ましく、９９．５％以上であることがより好ましい。本発明において、純度は、Ｚｎ、Ｚｒ、Ｈｆ、及びＴｉの化合物中の不純物元素（Ａｇ、Ａｌ、Ｂ、Ｂａ、Ｂｉ、Ｃａ、Ｃｄ、Ｃｌ、Ｃｏ、Ｃｒ、Ｃｕ、Ｆｅ、Ｇａ、Ｈｆ、Ｉｎ、Ｋ、Ｌｉ、Ｍｇ、Ｍｎ、Ｍｏ、Ｎａ、Ｎｉ、Ｐ、Ｐｂ、Ｓ、Ｓｉ、Ｓｒ、Ｔｉ、Ｔｌ、Ｖ、Ｚｎ及びＺｒ）の含有量を測定し、これらの合計含有量を１００質量％から差し引いた値とする。
　なお、対象となるＺｎ、Ｚｒ、Ｈｆ、及びＴｉの化合物自体を構成する元素が、前記したＺｎ、Ｚｒ、Ｈｆ、及びＴｉの化合物中の不純物元素に該当する場合、当該元素は不純物元素に含まれない。例えば、工程（ａ）で使用されるＺｎ、Ｚｒ、Ｈｆ、及びＴｉの化合物がＺｎＯである場合、ＺｎＯを構成するＺｎは、前記したＺｎ、Ｚｒ、Ｈｆ、及びＴｉの化合物中の不純物元素に含まれない。これらの不純物元素の含有量の測定方法としては、ＩＣＰ発光分析装置を用いた測定方法が挙げられる。
　Ｚｎ、Ｚｒ、Ｈｆ、及びＴｉの化合物は、Ｄ５０が０．１～１００μｍであることが好ましく、０．５～５０μｍであることがより好ましい。 Step (a) is a step of obtaining a reaction solution for partially hydrating magnesium hydroxide.
One or more compounds selected from the group consisting of Zn, Zr, Hf, and Ti are added to produce the magnesium hydroxide particles and magnesium oxide particles of the present invention. Thereby, whiteness, ultraviolet absorption, refractive index and the like are improved, and the magnesium hydroxide and magnesium oxide particles of the present invention suitable for an optical material or a coating agent for inkjet paper can be obtained.
The compound of Zn, Zr, Hf, and Ti is not particularly limited as long as it is a compound having these metal elements, and is an oxide, hydroxide, hydride, halide (fluoride, chloride, bromide, and iodine). ), Phosphates, carbonates, nitrates, etc., zinc oxide, zinc hydroxide, zinc chloride, zinc nitrate, zirconium oxide, zirconium hydroxide, zirconium chloride, zirconium nitrate, hafnium oxide, hafnium hydroxide, Hafnium chloride, hafnium nitrate, titanium oxide, titanium hydroxide, titanium chloride, and titanium nitrate are preferred.
The compound of Zn, Zr, Hf, and Ti preferably has a purity of 99.0% or more, and more preferably 99.5% or more. In the present invention, purity refers to impurity elements (Ag, Al, B, Ba, Bi, Ca, Cd, Cl, Co, Cr, Cu, Fe, Ga, Hf, Zn, Zr, and Ti). In, K, Li, Mg, Mn, Mo, Na, Ni, P, Pb, S, Si, Sr, Ti, Tl, V, Zn, and Zr) are measured, and the total content thereof is set to 100. The value is subtracted from the mass%.
In addition, when the element constituting the target Zn, Zr, Hf, and Ti compound itself corresponds to the impurity element in the Zn, Zr, Hf, and Ti compound, the element is included in the impurity element. I can't. For example, when the compound of Zn, Zr, Hf, and Ti used in step (a) is ZnO, Zn constituting ZnO is an impurity element in the compound of Zn, Zr, Hf, and Ti described above. Not included. As a measuring method of the content of these impurity elements, a measuring method using an ICP emission analyzer can be mentioned.
The compound of Zn, Zr, Hf, and Ti preferably has a D 50 of 0.1 to 100 μm, and more preferably 0.5 to 50 μm.
　Ｚｎ、Ｚｒ、Ｈｆ、及びＴｉの化合物からなる群より選択される１以上の化合物を含む分散液における溶媒として、イオン交換水が挙げられる。工程（ａ）で使用される分散液は、例えばイオン交換水にＺｎ、Ｚｒ、Ｈｆ、及びＴｉの化合物からなる群より選択される１以上の化合物を添加することにより得ることができる。 Examples of the solvent in the dispersion liquid containing one or more compounds selected from the group consisting of Zn, Zr, Hf, and Ti include ion-exchanged water. The dispersion used in the step (a) can be obtained, for example, by adding one or more compounds selected from the group consisting of compounds of Zn, Zr, Hf, and Ti to ion exchange water.
　工程（ａ）で使用される２価及び３価の金属元素の塩化物、並びに２価及び３価の金属元素の硝酸塩は、本発明の水酸化マグネシウム粒子の溶解度及び析出速度を制御するために添加される。２価及び３価の金属元素の塩化物、並びに２価及び３価の金属元素の硝酸塩として、塩化アルミニウム、塩化鉄、硝酸アルミニウム、及び硝酸鉄が好ましい。２価及び３価の金属元素の塩化物、並びに２価及び３価の金属元素の硝酸塩は、純度が９９．０％以上であることが好ましく、９９．５％以上であることがより好ましい。また、２価及び３価の金属元素の塩化物、並びに２価及び３価の金属元素の硝酸塩は、Ｄ５０が０．１～１００μｍであることが好ましく、０．５～５０μｍであることがより好ましい。 The divalent and trivalent metal element chlorides and divalent and trivalent metal element nitrates used in step (a) are used to control the solubility and precipitation rate of the magnesium hydroxide particles of the present invention. Added. As chlorides of divalent and trivalent metal elements and nitrates of divalent and trivalent metal elements, aluminum chloride, iron chloride, aluminum nitrate, and iron nitrate are preferable. The chlorides of divalent and trivalent metal elements and nitrates of divalent and trivalent metal elements preferably have a purity of 99.0% or more, and more preferably 99.5% or more. The divalent and trivalent metal element chlorides and the divalent and trivalent metal element nitrates preferably have a D 50 of 0.1 to 100 μm, preferably 0.5 to 50 μm. More preferred.
　本発明において、有機酸は、原料である一部水和針状酸化マグネシウムの溶解度を抑制するために添加される。有機酸としては、カルボキシル基を持つ脂肪族又は芳香族の有機酸が挙げられ、ギ酸、酢酸、プロピオン酸、酪酸、及び安息香酸が好ましい。 In the present invention, the organic acid is added to suppress the solubility of the partially hydrated acicular magnesium oxide as a raw material. Examples of the organic acid include aliphatic or aromatic organic acids having a carboxyl group, and formic acid, acetic acid, propionic acid, butyric acid, and benzoic acid are preferable.
　工程（ｂ）は、工程（ａ）で得られた水和反応のための反応液、及び一部水和針状酸化マグネシウム粒子を混合する工程である。工程（ｂ）で使用される一部水和針状酸化マグネシウム粒子は、レーザ回折散乱式粒度分布測定による体積累積の５０％粒子径（Ｄ５０）が０．１～１０μｍであり、比表面積が１．０～２０．０ｍ２／ｇであり、Ｉｇ－ｌｏｓｓが２．０～２５．０％である、表面の一部が水和された針状酸化マグネシウム、即ち部分的に水和された針状酸化マグネシウムである。このような一部水和針状酸化マグネシウムを用いることで、高い比表面積を有する鱗片状の一次粒子が凝集した棒状の水酸化マグネシウム粒子が得られる。
　工程（ｂ）で使用される一部水和針状酸化マグネシウム粒子のレーザ回折散乱式粒度分布測定による体積累積の５０％粒子径（Ｄ５０）が０．１μｍより小さいと、水和速度が速くなりすぎ、粗大な凝集粒子になる。また、Ｄ５０が１０μｍより大きいと、十分に水和反応が進まず酸化マグネシウムを含んだ粒子が残る。Ｄ５０は０．１～５．０μｍであるのが好ましい。
　工程（ｂ）で使用される一部水和針状酸化マグネシウム粒子の比表面積が２０．０ｍ２／ｇを超えると、水和速度が速くなりすぎ、粗大な凝集粒子になる。また、比表面積が１．０ｍ２／ｇ未満であると、十分に水和反応が進まず酸化マグネシウムを含んだ粒子が残る。比表面積は、２．０～１８．０ｍ２／ｇであるのが好ましく、３．０～１５．０ｍ２／ｇであるのがより好ましい。
　工程（ｂ）で使用される一部水和針状酸化マグネシウム粒子の付着水分と水和物構造中の水分の合計を示すＩｇ－ｌｏｓｓ（強熱減量）は、２．０～２５．０％（質量換算）である。すなわち、Ｉｇ－ｌｏｓｓは、本発明における一部水和針状酸化マグネシウム粒子における水和の程度を示す。Ｉｇ－ｌｏｓｓが２．０％より低いと、水和速度が不均一になりやすく、比表面積の低い不定形の粗大な凝集粒子となる。Ｉｇ－ｌｏｓｓが２５．０％を超えてしまうと、水和反応が抑制され、水和しきれない針状酸化マグネシウムが残留し、粗大な凝集粒子となり、好ましくない。水和反応を十分に進行させ、さらに高い比表面積を有する棒状水酸化マグネシウムを得るためには、Ｉｇ－ｌｏｓｓは、２．０～２０．０％であるのが好ましく、３．０～１８．０％であるのがより好ましい。本発明においてＩｇ－ｌｏｓｓは、一部水和針状酸化マグネシウム粒子を１０００℃で３６００秒焼成した後で測定することにより求められる。 Step (b) is a step of mixing the reaction solution for hydration obtained in step (a) and partially hydrated acicular magnesium oxide particles. The partially hydrated acicular magnesium oxide particles used in the step (b) have a volume cumulative 50% particle diameter (D 50 ) of 0.1 to 10 μm by laser diffraction scattering type particle size distribution measurement, and a specific surface area. 1.0 to 20.0 m 2 / g, Ig-loss is 2.0 to 25.0%, part of the surface is acicular magnesium oxide hydrated, ie partially hydrated It is acicular magnesium oxide. By using such partially hydrated acicular magnesium oxide, rod-shaped magnesium hydroxide particles in which scaly primary particles having a high specific surface area are aggregated are obtained.
When the 50% particle diameter (D 50 ) of volume accumulation by laser diffraction scattering type particle size distribution measurement of the partially hydrated acicular magnesium oxide particles used in step (b) is smaller than 0.1 μm, the hydration rate is fast. Becomes too coarse and becomes agglomerated particles. Further, a D 50 of greater than 10 [mu] m, fully hydrated reaction particles containing magnesium oxide is left not proceed. D 50 is preferably 0.1 to 5.0 μm.
When the specific surface area of the partially hydrated acicular magnesium oxide particles used in the step (b) exceeds 20.0 m 2 / g, the hydration rate becomes too fast, resulting in coarse aggregated particles. If the specific surface area is less than 1.0 m 2 / g, the hydration reaction does not proceed sufficiently and particles containing magnesium oxide remain. The specific surface area is preferably 2.0 to 18.0 m 2 / g, and more preferably 3.0 to 15.0 m 2 / g.
Ig-loss (loss on ignition) showing the total of the moisture content of the partially hydrated acicular magnesium oxide particles used in the step (b) and the moisture content in the hydrate structure is 2.0-25.0% (Mass conversion). That is, Ig-loss indicates the degree of hydration in the partially hydrated acicular magnesium oxide particles in the present invention. When Ig-loss is lower than 2.0%, the hydration rate tends to be non-uniform, resulting in irregular and coarse aggregated particles having a low specific surface area. If Ig-loss exceeds 25.0%, the hydration reaction is suppressed, acicular magnesium oxide that cannot be hydrated remains, and coarse aggregated particles are formed, which is not preferable. In order to sufficiently advance the hydration reaction and obtain rod-shaped magnesium hydroxide having a higher specific surface area, the Ig-loss is preferably 2.0 to 20.0%, and preferably 3.0 to 18. More preferably, it is 0%. In the present invention, Ig-loss is determined by measuring partially hydrated acicular magnesium oxide particles after firing at 1000 ° C. for 3600 seconds.
　このような工程（ｂ）で使用される一部水和針状酸化マグネシウムは、レーザ回折散乱式粒度分布測定による体積累積の５０％粒子径（Ｄ５０）が０．１～１０μｍであり、比表面積が１．０～１５．０ｍ２／ｇである、針状酸化マグネシウム粒子を、温度４０～９５℃及び湿度６０～９５％の恒温恒湿機内に、０．５～２４時間置く工程により得ることができる。通常、原料である針状酸化マグネシウムのＩｇ－ｌｏｓｓは０．１～１．０％であり、恒温恒湿機内に置く温度および時間を増加させることで、Ｉｇ－ｌｏｓｓを増加させることができる。
　工程（ｂ）で使用される一部水和針状酸化マグネシウムの原料となる針状酸化マグネシウムのＤ５０は、０．１～５．０μｍであるのが好ましい。
　また、工程（ｂ）で用意される一部水和針状酸化マグネシウムの原料となる針状酸化マグネシウムの比表面積は、２．０～１５．０ｍ２／ｇであるのが好ましく、３．０～１５．０ｍ２／ｇであるのがより好ましい。
　工程（ｂ）で使用される一部水和針状酸化マグネシウムの原料となる針状酸化マグネシウムの入手方法に特に限定はないが、例えば硫酸マグネシウムと炭酸ナトリウムを反応させて作成した針状の炭酸マグネシウムを精製し、１２００℃で焼成して得ることができる。 The partially hydrated acicular magnesium oxide used in such a step (b) has a volume cumulative 50% particle diameter (D 50 ) of 0.1 to 10 μm by laser diffraction scattering type particle size distribution measurement, Acicular magnesium oxide particles having a surface area of 1.0-15.0 m 2 / g are obtained by placing them in a thermo-hygrostat at a temperature of 40-95 ° C. and a humidity of 60-95% for 0.5-24 hours. be able to. Usually, the Ig-loss of acicular magnesium oxide as a raw material is 0.1 to 1.0%, and the Ig-loss can be increased by increasing the temperature and time placed in the thermo-hygrostat.
The D 50 of acicular magnesium oxide used as a raw material for the partially hydrated acicular magnesium oxide used in step (b) is preferably 0.1 to 5.0 μm.
The specific surface area of acicular magnesium oxide, which is a raw material for partially hydrated acicular magnesium oxide prepared in step (b), is preferably 2.0 to 15.0 m 2 / g, 3.0 More preferably, it is ˜15.0 m 2 / g.
Although there is no particular limitation on the method for obtaining acicular magnesium oxide used as a raw material for partially hydrated acicular magnesium oxide used in step (b), for example, acicular carbonate prepared by reacting magnesium sulfate and sodium carbonate. Magnesium can be purified and calcined at 1200 ° C.
　工程（ｂ）において使用される一部水和針状酸化マグネシウム及び分散液に含まれる各成分の量は、以下のとおりである。 The amount of each component contained in the partially hydrated acicular magnesium oxide used in the step (b) and the dispersion is as follows.
　Ｚｎ、Ｚｒ、Ｈｆ、及びＴｉの化合物からなる群より選択される１以上の化合物の量は、一部水和針状酸化マグネシウム粒子に対して、金属元素換算で０．１～５．０質量％である。Ｚｎ、Ｚｒ、Ｈｆ、及びＴｉの化合物からなる群より選択される化合物の量が０．１質量％より小さいと、コーティング剤として使用した場合、白色度、紫外線吸収性及び屈折率等が十分ではなく、粒子形状も鱗片状の一次粒子が凝集した棒状粒子にならず六角板状の粒子になる。また、Ｚｎ、Ｚｒ、Ｈｆ、及びＴｉの化合物からなる群より選択される化合物の量が５．０質量％より大きいと、本発明のような鱗片状の一次粒子が凝集した棒状粒子にならず六角柱状の粒子になる。Ｚｎ、Ｚｒ、Ｈｆ、及びＴｉの化合物からなる群より選択される１以上の化合物の量は、一部水和針状酸化マグネシウム粒子に対して、好ましくは０．２～４．０質量％であり、より好ましくは０．３～３．０質量％である。 The amount of one or more compounds selected from the group consisting of compounds of Zn, Zr, Hf, and Ti is 0.1 to 5.0 mass in terms of metal element with respect to partially hydrated acicular magnesium oxide particles. %. When the amount of the compound selected from the group consisting of Zn, Zr, Hf, and Ti is less than 0.1% by mass, when used as a coating agent, the whiteness, ultraviolet absorptivity and refractive index are not sufficient. In addition, the particle shape is not a rod-like particle in which the scaly primary particles are aggregated but a hexagonal plate-like particle. Further, when the amount of the compound selected from the group consisting of Zn, Zr, Hf, and Ti is larger than 5.0% by mass, the scaly primary particles as in the present invention are not aggregated rod-like particles. Hexagonal columnar particles. The amount of one or more compounds selected from the group consisting of compounds of Zn, Zr, Hf, and Ti is preferably 0.2 to 4.0% by mass with respect to the partially hydrated acicular magnesium oxide particles. More preferably, it is 0.3 to 3.0% by mass.
　２価及び３価の金属元素の塩化物、並びに２価及び３価の金属元素の硝酸塩からなる群より選択される１以上の化合物の量は、一部水和針状酸化マグネシウム粒子に対して、金属元素換算で０．１～５．０質量％である。添加量が０．１質量％より小さいと結晶の析出速度が遅くなり、単分散した六角柱状の粒子になり、添加量が５．０質量％より大きいと結晶の析出速度が速くなりすぎ、粗大な凝集粒子になる。２価及び３価の金属元素の塩化物、並びに２価及び３価の金属元素の硝酸塩からなる群より選択される１以上の化合物の量は、一部水和針状酸化マグネシウム粒子に対して、金属元素換算で好ましくは０．２～４．０質量％であり、より好ましくは０．３～３．０質量％である。 The amount of one or more compounds selected from the group consisting of chlorides of divalent and trivalent metal elements and nitrates of divalent and trivalent metal elements is based on partially hydrated acicular magnesium oxide particles. And 0.1 to 5.0% by mass in terms of metal element. When the addition amount is less than 0.1% by mass, the crystal precipitation rate becomes slow, resulting in monodispersed hexagonal columnar particles, and when the addition amount is more than 5.0% by mass, the crystal precipitation rate becomes too fast and coarse. Agglomerated particles. The amount of one or more compounds selected from the group consisting of chlorides of divalent and trivalent metal elements and nitrates of divalent and trivalent metal elements is based on partially hydrated acicular magnesium oxide particles. In terms of metal element, it is preferably 0.2 to 4.0% by mass, and more preferably 0.3 to 3.0% by mass.
　有機酸の添加量は、一部水和針状酸化マグネシウム粒子１００ｇに対して、０．０１～３．０ｍｏｌである。有機酸の添加量が一部水和針状酸化マグネシウム粒子１００ｇに対して、０．０１ｍｏｌより小さいと結晶の析出速度が遅くなり、単分散した六角板、又は六角柱状の粒子になり、３．０ｍｏｌより大きいと結晶の析出速度が速くなりすぎ、粗大な凝集粒子になる。有機酸の添加量は、一部水和針状酸化マグネシウム１００ｇに対して、好ましくは０．０１～２．０ｍｏｌである。 The amount of organic acid added is 0.01 to 3.0 mol with respect to 100 g of partially hydrated acicular magnesium oxide particles. 2. When the amount of organic acid added is less than 0.01 mol with respect to 100 g of partially hydrated acicular magnesium oxide particles, the rate of crystal precipitation becomes slow, resulting in monodispersed hexagonal plate or hexagonal columnar particles. If it is larger than 0 mol, the precipitation rate of crystals becomes too fast, resulting in coarse aggregated particles. The amount of the organic acid added is preferably 0.01 to 2.0 mol with respect to 100 g of partially hydrated acicular magnesium oxide.
　工程（ｂ）において、混合液における、一部水和針状酸化マグネシウムの濃度は、好ましくは２０～２００ｇ／Ｌであり、より好ましくは５０～１８０ｇ／Ｌであり、さらに好ましくは５０～１５０ｇ／Ｌである。すなわち、工程（ａ）で得られる反応液に対する一部水和針状酸化マグネシウムの量を、好ましくは２０～２００ｇ／Ｌ、より好ましくは５０～１８０ｇ／Ｌ、さらに好ましくは５０～１５０ｇ／Ｌに調整する。このような反応液における一部水和針状酸化マグネシウム濃度であれば、水和反応が十分に進む。 In the step (b), the concentration of the partially hydrated acicular magnesium oxide in the mixed solution is preferably 20 to 200 g / L, more preferably 50 to 180 g / L, and still more preferably 50 to 150 g / L. L. That is, the amount of partially hydrated acicular magnesium oxide in the reaction solution obtained in step (a) is preferably 20 to 200 g / L, more preferably 50 to 180 g / L, and still more preferably 50 to 150 g / L. adjust. If the concentration of partially hydrated acicular magnesium oxide in such a reaction solution is sufficient, the hydration reaction proceeds sufficiently.
　工程（ｃ）は、５０～１００℃の温度で、周速が７～２０ｍ／ｓである撹拌機を用いて混合する工程である。撹拌の回転数は、反応時の分散状態を制御するために調整される。
　本発明において、周速が７ｍ／ｓより小さいと、鱗片状の一次粒子が凝集した棒状の水酸化マグネシウムが得られない。また、周速が２０ｍ／ｓより大きいと、水酸化マグネシウム粒子が核生成時に過度に分散し、単分散した六角板、又は六角柱状の水酸化マグネシウム粒子になり、本発明のような水酸化マグネシウム粒子が得られない。このような撹拌のための装置として、上記した周速を満たす限り特に限定されないが、ホモディスパー（プライミクス社、Ｔ．Ｋ．ホモディスパー）等が挙げられる。周速は、好ましくは８～１８ｍ／ｓであり、より好ましくは９～１５ｍ／ｓである。工程（ｃ）における反応温度は、好ましくは５５～９５℃であり、より好ましくは６０～９５℃である。工程（ｃ）において、混合時間は、水和反応の程度に応じて変更でき、例えば１０～３６０分、好ましくは２０～２００分とすることができる。 Step (c) is a step of mixing using a stirrer having a peripheral speed of 7 to 20 m / s at a temperature of 50 to 100 ° C. The number of rotations of stirring is adjusted to control the dispersion state during the reaction.
In the present invention, if the peripheral speed is less than 7 m / s, rod-shaped magnesium hydroxide in which scaly primary particles are aggregated cannot be obtained. On the other hand, when the peripheral speed is higher than 20 m / s, the magnesium hydroxide particles are excessively dispersed at the time of nucleation to form mono-dispersed hexagonal plate or hexagonal columnar magnesium hydroxide particles, and the magnesium hydroxide as in the present invention. Particles cannot be obtained. The apparatus for stirring is not particularly limited as long as the above peripheral speed is satisfied, and examples thereof include homodispers (Primics Co., Ltd., TK homodispers). The peripheral speed is preferably 8 to 18 m / s, more preferably 9 to 15 m / s. The reaction temperature in the step (c) is preferably 55 to 95 ° C, more preferably 60 to 95 ° C. In the step (c), the mixing time can be changed according to the degree of the hydration reaction, and can be, for example, 10 to 360 minutes, preferably 20 to 200 minutes.
　工程（ｄ）は、３０～１００℃の温度で、撹拌して水酸化マグネシウムスラリーを得る工程である。これにより、工程（ｃ）において未反応の一部水和針状酸化マグネシウムの水和反応を促進させて、水酸化マグネシウムとすることができる。温度は、好ましくは５０～９５℃であり、より好ましくは７０～９０℃である。撹拌速度は、水酸化マグネシウムスラリーが十分撹拌できる程度であればよく、特に制限はないが、例えば、３枚ばねの攪拌機で１００～５００ｒｐｍとすることができる。撹拌時間は、水和反応が十分に進み所望の水酸化マグネシウムスラリーが得られる時間であれば、特に制限なく、例えば、０．５～６時間とすることができる。 Step (d) is a step of stirring to obtain a magnesium hydroxide slurry at a temperature of 30 to 100 ° C. Thereby, in step (c), the hydration reaction of the unreacted partially hydrated acicular magnesium oxide can be promoted to obtain magnesium hydroxide. The temperature is preferably 50 to 95 ° C, more preferably 70 to 90 ° C. The stirring speed is not particularly limited as long as the magnesium hydroxide slurry can be sufficiently stirred. For example, the stirring speed can be set to 100 to 500 rpm with a three-spring stirrer. The stirring time is not particularly limited as long as the hydration reaction proceeds sufficiently and a desired magnesium hydroxide slurry can be obtained. For example, the stirring time can be 0.5 to 6 hours.
　工程（ｅ）は、工程（ｄ）の水酸化マグネシウムスラリーをろ過、水洗、乾燥させて、水酸化マグネシウム粒子を得る工程である。これにより、本発明の水酸化マグネシウム粒子が得られる。 Step (e) is a step of obtaining magnesium hydroxide particles by filtering, washing and drying the magnesium hydroxide slurry of step (d). Thereby, the magnesium hydroxide particle of this invention is obtained.
　本発明の酸化マグネシウム粒子は、本発明の水酸化マグネシウム粒子、又は本発明の工程（ａ）～工程（ｅ）を含む製造方法により得られる水酸化マグネシウム粒子を、大気雰囲気中で、５００～１４００℃で焼成する工程を含む方法により得られる。
　水酸化マグネシウム粒子の焼成は、電気炉等を使用して焼成することにより行うことができる。ここで、焼成は、所定の昇温速度で焼成温度まで昇温させる工程、及び焼成温度で所定の時間保持する工程を含む焼成方法により達成することができる。昇温速度は、好ましくは１～２０℃／分であり、より好ましくは３～１０℃／分である。焼成温度は、５００～１４００℃であり、好ましくは６００～１３００℃である。焼成温度で保持する時間である焼成時間は、好ましくは０．１～５時間であり、より好ましくは、０．１～３時間である。ここで、焼成温度が５００℃未満であると、熱量が不足し水酸化マグネシウムが残る。一方、焼成温度が１４００℃を超えると、酸化マグネシウムが粒成長して、棒状の酸化マグネシウムにはならない。 The magnesium oxide particles of the present invention are obtained by subjecting the magnesium hydroxide particles of the present invention or the magnesium hydroxide particles obtained by the production method including the steps (a) to (e) of the present invention to 500 to 1400 in an air atmosphere. It is obtained by a method including a step of baking at 0 ° C.
The firing of the magnesium hydroxide particles can be performed by firing using an electric furnace or the like. Here, the firing can be achieved by a firing method including a step of raising the temperature to a firing temperature at a predetermined rate of temperature rise and a step of holding at the firing temperature for a predetermined time. The rate of temperature rise is preferably 1 to 20 ° C./min, more preferably 3 to 10 ° C./min. The firing temperature is 500 to 1400 ° C., preferably 600 to 1300 ° C. The firing time, which is the time for holding at the firing temperature, is preferably from 0.1 to 5 hours, more preferably from 0.1 to 3 hours. Here, if the firing temperature is less than 500 ° C., the amount of heat is insufficient and magnesium hydroxide remains. On the other hand, when the firing temperature exceeds 1400 ° C., magnesium oxide grows and does not become rod-shaped magnesium oxide.
　このようにして、分散性に優れた棒状の水酸化マグネシウム粒子及び酸化マグネシウム粒子が得られる。本発明の製造方法で得られる水酸化マグネシウム粒子及び酸化マグネシウム粒子の一次粒子の形状は、好ましくは鱗片状であり、図１の鱗片状の一例と同様である。本発明の鱗片状の一次粒子は、厚みが０．０１～０．１μｍ、好ましくは０．０１～０．０５μｍの範囲であり、面の外接円の直径が０．２～５μｍ、好ましくは０．５～２．５μｍの範囲である。より好ましくは、本発明の製造方法により、本発明の鱗片状の一次粒子が凝集した棒状の水酸化マグネシウム粒子及び酸化マグネシウム粒子が得られる。 Thus, rod-like magnesium hydroxide particles and magnesium oxide particles having excellent dispersibility can be obtained. The shape of the primary particles of magnesium hydroxide particles and magnesium oxide particles obtained by the production method of the present invention is preferably scaly and is the same as the scaly example of FIG. The scaly primary particles of the present invention have a thickness in the range of 0.01 to 0.1 μm, preferably 0.01 to 0.05 μm, and the diameter of the circumscribed circle of the surface is 0.2 to 5 μm, preferably 0. The range is from 5 to 2.5 μm. More preferably, by the production method of the present invention, rod-shaped magnesium hydroxide particles and magnesium oxide particles in which the flaky primary particles of the present invention are aggregated are obtained.
　以下、本発明を実施例及び比較例により更に詳細に説明するが、本発明はこれら実施例により限定されるものではない。
　［分析方法］
（１）レーザ回折散乱式粒度分布測定
　レーザ回折散乱式粒度分布測定装置（商品名：ＭＴ３３００、日機装社製）を使用して、体積基準の累積１０％粒子径（Ｄ１０）、体積基準の累積５０％粒子径（Ｄ５０）、及び体積基準の累積９０％粒子径（Ｄ９０）を測定した。
（２）元素の質量測定法
　粒子中の測定対象となる元素（Ａｇ、Ａｌ、Ｂ、Ｂａ、Ｂｉ、Ｃａ、Ｃｄ、Ｃｏ、Ｃｒ、Ｃｕ、Ｆｅ、Ｇａ、Ｈｆ、Ｉｎ、Ｋ、Ｌｉ、Ｍｇ、Ｍｎ、Ｍｏ、Ｎａ、Ｎｉ、Ｐ、Ｐｂ、Ｓｉ、Ｓｒ、Ｔｉ、Ｔｌ、Ｖ、Ｚｎ、及びＺｒ）は、ＩＣＰ発光分析装置（商品名：ＳＰＳ－５１００、セイコーインスツルメンツ製）を使用して、試料を酸に溶解した後、質量を測定した。
　Ｃｌは、分光光度計（商品名：ＵＶ－２５５０、島津製作所）を使用して、資料を酸に溶解した後、質量を測定した。
（３）ＢＥＴ比表面積測定法
　比表面積測定装置（商品名：Ｍａｃｓｏｒｂ１２１０、マウンテック社製）を使用して、ガス吸着法により比表面積を測定した。
（４）Ｉｇ－ｌｏｓｓ測定法
　電気炉（丸祥電器株式会社製）を使用して、１０００℃で３６００秒の条件によりＩｇ－ｌｏｓｓを測定した。 EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further in detail, this invention is not limited by these Examples.
[Analysis method]
(1) a laser diffraction scattering particle size distribution measurement laser diffraction scattering particle size distribution measuring apparatus (trade name: MT3300, manufactured by Nikkiso Co., Ltd.) was used, a cumulative 10% particle diameter on a volume basis (D 10), the cumulative volume-based A 50% particle size (D 50 ) and a volume-based cumulative 90% particle size (D 90 ) were measured.
(2) Element mass measurement method Element to be measured in particle (Ag, Al, B, Ba, Bi, Ca, Cd, Co, Cr, Cu, Fe, Ga, Hf, In, K, Li, Mg , Mn, Mo, Na, Ni, P, Pb, Si, Sr, Ti, Tl, V, Zn, and Zr) using an ICP emission analyzer (trade name: SPS-5100, manufactured by Seiko Instruments Inc.) After dissolving the sample in acid, the mass was measured.
Using a spectrophotometer (trade name: UV-2550, Shimadzu Corporation), Cl was dissolved in an acid and then mass was measured.
(3) BET specific surface area measuring method The specific surface area was measured by the gas adsorption method using the specific surface area measuring apparatus (trade name: Macsorb1210, manufactured by Mountec Co., Ltd.).
(4) Ig-loss measurement method Using an electric furnace (manufactured by Marusho Denki Co., Ltd.), Ig-loss was measured under conditions of 1000 ° C and 3600 seconds.
〔実施例１〕
　硫酸マグネシウム溶液と炭酸ナトリウムを反応させて作成した針状の炭酸マグネシウムを、焼成温度１２００℃で焼成することで作成した、５０％粒子径（Ｄ５０）が１．１２μｍであり、比表面積が１０．６４ｍ２／ｇである酸化マグネシウムを、温度８０℃、湿度９０％の恒温恒湿機内に３時間置き、表面を一部水和させて、比表面積が１３．４６ｍ２／ｇであり、Ｉｇ－ｌｏｓｓが９．０８％である、一部水和針状酸化マグネシウムを得た。
　反応に使用する一部水和針状酸化マグネシウムに対して、金属元素換算で０．５質量％の酸化亜鉛、及びイオン交換水１リットルを含むイオン交換水溶液に、金属元素換算で０．５質量％の塩化アルミニウム・６水和物、及び一部水和針状酸化マグネシウム１００ｇに対して０．０２ｍｏｌのプロピオン酸を添加することで反応液を作製した。作製した反応液の温度を６０℃まで昇温させ、表面を一部水和させた酸化マグネシウムを１００ｇ投入して、混合液を得た。酸化マグネシウムを投入後、反応液の温度を９５℃まで上昇させ、撹拌機（プライミクス社製　T.K.ホモディスパー）で、周速が９．１ｍ/ｓとなるように調整し、１時間反応させた。
　その後、９０℃で、スラリ－が十分撹拌できる程度の回転速度で４時間撹拌することにより、水酸化マグネシウムスラリーを作製した。作製した水酸化マグネシウムスラリーをろ過、水洗、乾燥させて、本発明の棒状水酸化マグネシウム粒子を得た。 [Example 1]
Acicular magnesium carbonate prepared by reacting a magnesium sulfate solution and sodium carbonate was fired at a firing temperature of 1200 ° C., and the 50% particle diameter (D 50 ) was 1.12 μm and the specific surface area was 10 magnesium oxide is .64m 2 / g, the temperature 80 ° C., placed 3 hours in a constant-temperature constant-humidity cabin humidity of 90% of the surface by partially hydrated, specific surface area of 13.46m 2 / g, Ig A partially hydrated acicular magnesium oxide having a loss of 9.08% was obtained.
0.5 mass% in terms of metal element in an ion exchange aqueous solution containing 0.5% by mass of zinc oxide in terms of metal element and 1 liter of ion-exchanged water with respect to partially hydrated acicular magnesium oxide used in the reaction A reaction solution was prepared by adding 0.02 mol of propionic acid to 100 g of 100% aluminum chloride hexahydrate and 100 g of partially hydrated acicular magnesium oxide. The temperature of the prepared reaction solution was raised to 60 ° C., and 100 g of magnesium oxide whose surface was partially hydrated was added to obtain a mixed solution. After adding magnesium oxide, the temperature of the reaction liquid was raised to 95 ° C., and the peripheral speed was adjusted to 9.1 m / s with a stirrer (TK homodisper manufactured by PRIMIX Co., Ltd.) and reacted for 1 hour.
Thereafter, a magnesium hydroxide slurry was prepared by stirring at 90 ° C. for 4 hours at a rotation speed at which the slurry could be sufficiently stirred. The produced magnesium hydroxide slurry was filtered, washed with water, and dried to obtain rod-shaped magnesium hydroxide particles of the present invention.
〔実施例２〕
　塩化アルミニウムの変わりに硫酸アルミニウムを使用した以外は、実施例１と同様に行った。 [Example 2]
It carried out like Example 1 except having used aluminum sulfate instead of aluminum chloride.
〔実施例３〕
　針状酸化マグネシウムを、温度６０℃、湿度９０％の恒温恒湿機内に、１２時間置き、表面を一部水和させ、比表面積を１０．１８ｍ２／ｇ、Ｉｇ－ｌｏｓｓを２１．４２％とした以外は、実施例１と同様に行った。 Example 3
Acicular magnesium oxide is placed in a constant temperature and humidity machine at a temperature of 60 ° C. and a humidity of 90% for 12 hours to partially hydrate the surface, the specific surface area is 10.18 m 2 / g, and the Ig-loss is 21.42%. The procedure was the same as in Example 1 except that.
〔実施例４〕
　実施例１で作製した水酸化マグネシウムを、大気雰囲気中で６００℃×１時間焼成し、酸化マグネシウム粒子を得た。 Example 4
Magnesium hydroxide produced in Example 1 was baked in an air atmosphere at 600 ° C. for 1 hour to obtain magnesium oxide particles.
〔実施例５〕
　実施例１で作製した水酸化マグネシウムを、大気雰囲気中で８００℃×１時間焼成し、酸化マグネシウム粒子を得た。 Example 5
Magnesium hydroxide produced in Example 1 was baked at 800 ° C. for 1 hour in an air atmosphere to obtain magnesium oxide particles.
〔実施例６〕
実施例１で作製した水酸化マグネシウムを、大気雰囲気中で１０００℃×１時間焼成し、酸化マグネシウム粒子を得た。 Example 6
The magnesium hydroxide produced in Example 1 was baked at 1000 ° C. for 1 hour in an air atmosphere to obtain magnesium oxide particles.
〔実施例７〕
　プロピオン酸を酢酸に変更した以外は、実施例１と同様に行った。 Example 7
The same procedure as in Example 1 was performed except that propionic acid was changed to acetic acid.
〔実施例８〕
　プロピオン酸を酪酸に変更した以外は、実施例１と同様に行った。 Example 8
The same procedure as in Example 1 was performed except that propionic acid was changed to butyric acid.
〔比較例１〕
　５０％粒子径が１．１９μｍであり、比表面積が１０．８２ｍ２／ｇである、針状ではない酸化マグネシウムを用いたこと以外は、実施例１と同様に行った。なお、原料である酸化マグネシウムのＩｇ－ｌｏｓｓは、０．７８％であった。 [Comparative Example 1]
The same procedure as in Example 1 was performed except that non-acicular magnesium oxide having a 50% particle size of 1.19 μm and a specific surface area of 10.82 m 2 / g was used. The Ig-loss of the raw material magnesium oxide was 0.78%.
〔比較例２〕
　酸化マグネシウムの表面を一部水和せずに用いたこと以外は、実施例１と同様に行った。 [Comparative Example 2]
The same operation as in Example 1 was performed except that the surface of magnesium oxide was used without being partially hydrated.
〔比較例３〕
　針状酸化マグネシウムを、温度８０℃、湿度９０％の恒温恒湿機内に、１２時間置き、比表面積を８．０９ｍ２／ｇ、Ｉｇ－ｌｏｓｓを２６．７８％とした以外は、実施例１と同様に行った。
〔比較例４〕
　針状酸化マグネシウムを、温度６０℃、湿度９０％の恒温恒湿機内に、３時間置き、比表面積を１２．４１ｍ２／ｇ、Ｉｇ－ｌｏｓｓを１１．５％とし、焼成温度を１５００℃とした以外は、実施例４と同様に行った。 [Comparative Example 3]
Example 1 except that acicular magnesium oxide was placed in a thermo-hygrostat at a temperature of 80 ° C. and a humidity of 90% for 12 hours, the specific surface area was 8.09 m 2 / g, and the Ig-loss was 26.78%. As well as.
[Comparative Example 4]
Acicular magnesium oxide is placed in a thermostat at a temperature of 60 ° C. and a humidity of 90% for 3 hours, the specific surface area is 12.41 m 2 / g, the Ig-loss is 11.5%, and the firing temperature is 1500 ° C. The same procedure as in Example 4 was performed except that.
　以上の実施例、及び比較例によって得られた水酸化マグネシウム粒子及び酸化マグネシウム粒子に関する測定結果を表１に示す。 Table 1 shows the measurement results regarding the magnesium hydroxide particles and the magnesium oxide particles obtained in the above examples and comparative examples.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　表１の結果からも明らかなように、本発明の水酸化マグネシウム粒子及び酸化マグネシウム粒子は、鱗片状の一次粒子が凝集した棒状であり、５０％粒子径（Ｄ５０）が１．０～１０．０μｍであり、比表面積が１０ｍ２／ｇ以上であった。また、Ｄ９０／Ｄ１０が１０以下であり、分散性が優れていることが確認された。一方、表２の結果から明らかなように、比較例１では、球状の水酸化マグネシウム粒子であった。また比較例２の水酸化マグネシウム粒子は、比表面積が８．２６ｍ２／ｇであった。また比較例３の水酸化マグネシウム粒子は、様々な形状の凝集体が混在した不定形であり、比表面積が７．４５ｍ２／ｇであった。また比較例４の酸化マグネシウム粒子は、粒成長して鱗片状の水酸化マグネシウムが酸化マグネシウムとなるときに形状が失われて不定形となり、比表面積は６．８７ｍ２／ｇであった。 As is apparent from the results in Table 1, the magnesium hydroxide particles and the magnesium oxide particles of the present invention are rod-like aggregates of scale-like primary particles, and the 50% particle diameter (D 50 ) is 1.0 to 10 The specific surface area was 10 m 2 / g or more. Also, D is a 90 / D 10 is 10 or less, it was confirmed that superior dispersibility. On the other hand, as is clear from the results in Table 2, in Comparative Example 1, the particles were spherical magnesium hydroxide particles. Further, the magnesium hydroxide particles of Comparative Example 2 had a specific surface area of 8.26 m 2 / g. Further, the magnesium hydroxide particles of Comparative Example 3 were indeterminate in which aggregates of various shapes were mixed, and the specific surface area was 7.45 m 2 / g. Further, the magnesium oxide particles of Comparative Example 4 lost their shape and became irregular when the scale-like magnesium hydroxide was converted to magnesium oxide, and the specific surface area was 6.87 m 2 / g.
　本発明の水酸化マグネシウム及び酸化マグネシウムの製造方法は、原料の酸化マグネシウムを恒温恒湿機などで水和調整するだけで、簡単に比表面積をコントロールできるために、容易に水酸化マグネシウム及び酸化マグネシウムを製造することができる。
　本発明の水酸化マグネシウム粒子及び酸化マグネシウム粒子は、棒状であり、５０％粒子径が小さく、かつ均一であり、分散性が良く、高い比表面積を有するため様々な分野で有用性が高い。また、本発明の製造方法は、上記のような水酸化マグネシウム及び酸化マグネシウム粒子を容易に調製することができるため、利便性が高い。本発明の水酸化マグネシウム粒子は、インクジェット用紙のコーティング剤、難燃剤、蓄熱材料、触媒及び電子材料等が挙げられ、酸化マグネシウム粒子の用途としては、光学材料、インクジェット用紙のコーティング剤、触媒及び電子材料等の用途に用いることができる。 The method for producing magnesium hydroxide and magnesium oxide of the present invention can easily control the specific surface area by simply hydrating the raw material magnesium oxide with a thermo-hygrostat, etc. Can be manufactured.
Magnesium hydroxide particles and magnesium oxide particles of the present invention are rod-shaped, have a small 50% particle size, are uniform, have good dispersibility, and have a high specific surface area, so they are highly useful in various fields. Moreover, since the manufacturing method of this invention can prepare the above magnesium hydroxide and magnesium oxide particle | grains easily, it is highly convenient. Magnesium hydroxide particles of the present invention include inkjet paper coating agents, flame retardants, heat storage materials, catalysts and electronic materials, etc. Magnesium oxide particles are used as optical materials, inkjet paper coating agents, catalysts and electronic materials. It can be used for applications such as materials.

Claims (8)

  1. 　鱗片状の一次粒子が凝集した棒状であり、レーザ回折散乱式粒度分布測定による体積累積の５０％粒子径（Ｄ５０）が１．０～１０．０μｍであり、比表面積が１０ｍ２/ｇ以上である、水酸化マグネシウム粒子。 Scale-like primary particles are agglomerated rod-shaped, volume cumulative 50% particle diameter (D 50 ) measured by laser diffraction scattering particle size distribution measurement is 1.0 to 10.0 μm, and specific surface area is 10 m 2 / g or more Magnesium hydroxide particles.
  2. 　さらに、Ｚｎ、Ｚｒ、Ｈｆ、及びＴｉからなる群より選択される１以上の金属元素を金属元素換算で０．１～５．０質量％含み、２価及び３価の金属元素からなる群より選択される１以上の更なる金属元素（ただし、Ｚｎ、Ｚｒ、Ｈｆ、及びＴｉは除く）を金属元素換算で０．１～５．０質量％含む、請求項１記載の水酸化マグネシウム粒子。 Furthermore, from the group consisting of divalent and trivalent metal elements containing 0.1 to 5.0 mass% of one or more metal elements selected from the group consisting of Zn, Zr, Hf, and Ti in terms of metal elements The magnesium hydroxide particle according to claim 1, comprising 0.1 to 5.0% by mass of one or more selected additional metal elements (excluding Zn, Zr, Hf, and Ti) in terms of metal elements.
  3. 　鱗片状の一次粒子が凝集した棒状であり、レーザ回折散乱式粒度分布測定による体積累積の５０％粒子径（Ｄ５０）が１．０～１０．０μｍであり、比表面積が１０ｍ２/ｇ以上である、酸化マグネシウム粒子。 Scale-like primary particles are agglomerated rod-shaped, volume cumulative 50% particle diameter (D 50 ) measured by laser diffraction scattering particle size distribution measurement is 1.0 to 10.0 μm, and specific surface area is 10 m 2 / g or more Magnesium oxide particles.
  4. 　さらに、Ｚｎ、Ｚｒ、Ｈｆ、及びＴｉからなる群より選択される１以上の金属元素を金属元素換算で０．１～５．０質量％含み、２価及び３価の金属からなる群より選択される１以上の更なる金属元素（ただし、Ｚｎ、Ｚｒ、Ｈｆ、及びＴｉは除く）を金属元素換算で０．１～５．０質量％含む、請求項３記載の酸化マグネシウム粒子。 Furthermore, it contains 0.1 to 5.0% by mass of one or more metal elements selected from the group consisting of Zn, Zr, Hf, and Ti, selected from the group consisting of divalent and trivalent metals. The magnesium oxide particle according to claim 3, comprising 0.1 to 5.0% by mass of one or more additional metal elements (excluding Zn, Zr, Hf, and Ti) in terms of metal elements.
  5. 　水酸化マグネシウム粒子の製造方法であって、
    （ａ）Ｚｎ、Ｚｒ、Ｈｆ、及びＴｉの化合物からなる群より選択される１以上の化合物を含む分散液に、２価及び３価の金属元素の塩化物、並びに２価及び３価の金属元素の硝酸塩からなる群より選択される１以上の化合物（ただし、Ｚｎ、Ｚｒ，Ｈｆ、及びＴｉの化合物は除く）を添加し、さらに、有機酸を添加して反応液を得る工程、
    （ｂ）工程（ａ）の反応液、及びレーザ回折散乱式粒度分布測定による体積累積の５０％粒子径（Ｄ５０）が０．１～１０μｍであり、比表面積が１．０～２０．０ｍ２／ｇであり、Ｉｇ－ｌｏｓｓが２．０～２５．０％である、一部水和針状酸化マグネシウムを混合して、混合液を得る工程
    （ここで、
    　Ｚｎ、Ｚｒ、Ｈｆ、及びＴｉの化合物からなる群より選択される１以上の化合物は、一部水和針状酸化マグネシウムに対して、金属元素換算で０．１～５．０質量％であり、
    　２価及び３価の金属元素の塩化物、並びに２価及び３価の金属元素の硝酸塩からなる群より選択される１以上の化合物は、一部水和針状酸化マグネシウムに対して、金属元素換算で０．１～５．０質量％であり、
    　有機酸は、一部水和針状酸化マグネシウム１００ｇに対し、０．０１～３．０ｍｏｌである）、
    （ｃ）工程（ｂ）の混合液を５０～１００℃の温度で、周速が７～２０ｍ／ｓである撹拌機を用いて混合する工程、
    （ｄ）３０～１００℃の温度で、撹拌して水酸化マグネシウムスラリーを得る工程、及び
    （ｅ）工程（ｄ）の水酸化マグネシウムスラリーをろ過、水洗、乾燥させて、水酸化マグネシウム粒子を得る工程
    を含む、水酸化マグネシウム粒子の製造方法。     A method for producing magnesium hydroxide particles, comprising:
    (A) In a dispersion containing one or more compounds selected from the group consisting of Zn, Zr, Hf, and Ti, divalent and trivalent metal element chlorides, and divalent and trivalent metals Adding one or more compounds selected from the group consisting of elemental nitrates (excluding Zn, Zr, Hf, and Ti compounds), and further adding an organic acid to obtain a reaction solution;
    (B) The reaction liquid in step (a) and the volume cumulative 50% particle diameter (D 50 ) measured by laser diffraction / scattering particle size distribution measurement are 0.1 to 10 μm, and the specific surface area is 1.0 to 20.0 m. 2 / g and Ig-loss is 2.0 to 25.0%, a partially hydrated acicular magnesium oxide is mixed to obtain a mixture (where,
    One or more compounds selected from the group consisting of compounds of Zn, Zr, Hf, and Ti are 0.1 to 5.0% by mass in terms of metal elements with respect to partially hydrated acicular magnesium oxide. ,
    One or more compounds selected from the group consisting of divalent and trivalent metal element chlorides, and divalent and trivalent metal element nitrates are partially hydrated with acicular magnesium oxide. 0.1 to 5.0 mass% in terms of conversion,
    The organic acid is 0.01 to 3.0 mol with respect to 100 g of partially hydrated acicular magnesium oxide)
    (C) mixing the liquid mixture of step (b) at a temperature of 50 to 100 ° C. using a stirrer having a peripheral speed of 7 to 20 m / s,
    (D) a step of obtaining a magnesium hydroxide slurry by stirring at a temperature of 30 to 100 ° C., and (e) filtering, washing with water and drying the magnesium hydroxide slurry of step (d) to obtain magnesium hydroxide particles. The manufacturing method of a magnesium hydroxide particle including a process.
  6. 　工程（ｂ）の一部水和針状酸化マグネシウムが、レーザ回折散乱式粒度分布測定による体積累積の５０％粒子径（Ｄ５０）が０．１～１０μｍであり、比表面積が１．０～１５．０ｍ２／ｇである針状酸化マグネシウム粒子を、温度４０～９５℃、湿度６０～９５％の恒温恒湿機内に、０．５～２４時間置くことにより得られる、請求項５記載の方法。 The partially hydrated acicular magnesium oxide in step (b) has a 50% cumulative volume particle diameter (D 50 ) of 0.1 to 10 μm as measured by laser diffraction scattering particle size distribution measurement, and a specific surface area of 1.0 to 10 μm. The acicular magnesium oxide particles having a temperature of 15.0 m 2 / g are obtained by placing the acicular magnesium oxide particles in a thermostat at a temperature of 40 to 95 ° C and a humidity of 60 to 95% for 0.5 to 24 hours. Method.
  7. 　工程（ｂ）の混合液における、一部水和針状酸化マグネシウムの濃度が２０～２００ｇ／Ｌである、請求項５又は６記載の方法。 The method according to claim 5 or 6, wherein the concentration of the partially hydrated acicular magnesium oxide in the mixed solution in the step (b) is 20 to 200 g / L.
  8. 　酸化マグネシウム粒子の製造方法であって、請求項１又は２記載の水酸化マグネシウム粒子或いは請求項５～７いずれか１項記載の方法により得られる水酸化マグネシウム粒子を、大気雰囲気中で、５００～１４００℃で焼成する工程を含む、酸化マグネシウム粒子の製造方法。 A method for producing magnesium oxide particles, wherein the magnesium hydroxide particles according to claim 1 or 2 or the magnesium hydroxide particles obtained by the method according to any one of claims 5 to 7 The manufacturing method of a magnesium oxide particle including the process baked at 1400 degreeC.
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