# US 10,501,635 B2 · Magnesium oxide powder, resin composition including same, and method for producing magnesium oxide powder

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- Number: US 10,501,635 B2
- Document ID: US10501635B2
- Status: Granted
- Kind: B2
- Application number: 15/554,472
- Filed: 2016-03-02
- Published: 2018-02-15
- Granted: 2019-12-10
- Earliest claimed: 2015-03-16
- Assignees: Ube Material Industries, Ltd.
- Applicants: Ube Material Industries, Ltd.
- Inventors: Naoto Nishida; Tatsuki Okutsu; Naoki Funabashi; Akira Yoshida
- Web page: https://patentgrep.com/patent/US10501635B2

## CPC

- C09C 1/028: {Compounds containing only magnesium as metal}
- C01F 5/02: Magnesia
- C01F 5/08: by calcining magnesium hydroxide
- C01F 5/14: Magnesium hydroxide
- C01F 5/24: Magnesium carbonates
- C08K 3/22: of metals
- C08K 3/26: Carbonates; Bicarbonates
- C08K 9/02: Ingredients treated with inorganic substances
- C09C 3/063: {Coating}
- C01P 2002/70: defined by measured X-ray, neutron or electron diffraction data
- C01P 2004/04: obtained by TEM, STEM, STM or AFM
- C01P 2004/61: Micrometer sized, i.e. from 1-100 micrometer
- C01P 2004/62: Submicrometer sized, i.e. from 0.1-1 micrometer
- C01P 2004/80: Particles consisting of a mixture of two or more inorganic phases
- C01P 2004/84: one phase coated with the other
- C01P 2006/10: Solid density
- C01P 2006/62: L* (lightness axis)
- C01P 2006/63: a* (red-green axis)
- C01P 2006/64: b* (yellow-blue axis)
- C08K 2003/222: {Magnesia, i.e. magnesium oxide}
- C08K 2003/267: {Magnesium carbonate}
- C08K 2201/005: Additives being defined by their particle size in general
- C09C: TREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS, TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES (treatment of materials specially adapted to enhance their filling properties in mortars, concrete or artificial stone C04B14/00, C04B18/00, C04B20/00); PREPARATION OF CARBON BLACK {; PREPARATION OF INORGANIC MATERIALS WHICH ARE NO SINGLE CHEMICAL COMPOUNDS AND WHICH ARE MAINLY USED AS PIGMENTS OR FILLERS}
- C01F: COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS (metal hydrides {monoborane, diborane or addition complexes thereof} C01B6/00; salts of oxyacids of halogens C01B11/00; peroxides, salts of peroxyacids C01B15/00; sulfides or polysulfides of magnesium, calcium, strontium, or barium C01B17/42; thiosulfates, dithionites, polythionates C01B17/64; compounds containing selenium or tellurium C01B19/00; binary compounds of nitrogen with metals C01B21/06; azides C01B21/08; {compounds other than ammonia or cyanogen containing nitrogen and non-metals and optionally metals C01B21/082; amides or imides of silicon C01B21/087}; metal {imides or} amides C01B21/092, {C01B21/0923}; nitrites C01B21/50; {compounds of noble gases C01B23/0005}; phosphides C01B25/08; salts of oxyacids of phosphorus C01B25/16; carbides C01B32/90; compounds containing silicon C01B33/00; compounds containing boron C01B35/00; compounds having molecular sieve properties but not having base-exchange properties C01B37/00; compounds having molecular sieve and base-exchange properties, e.g. crystalline zeolites, C01B39/00; cyanides C01C3/08; salts of cyanic acid C01C3/14; salts of cyanamide C01C3/16; thiocyanates C01C3/20; {double sulfates of magnesium with sodium or potassium C01D5/12; with other alkali metals C01D15/00, C01D17/00})
- C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09)
- C01P: INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS

## Abstract

To provide magnesium oxide which is excellent in hydration resistance and hardly causes volume expansion due to hydration and the like, a resin composition containing the same, and a method for producing the magnesium oxide powder. Magnesium oxide powder having a coating layer mainly comprising basic magnesium carbonate in the surface layer, when the amounts of substances of water vapor and carbon dioxide among the gas generated by thermal decomposition at 50 to 500° C. are respectively designated as m-H2O and m-CO2, in a heating evolved gas analysis (EGA-MS) method, the molar fraction represented by m-CO2/(m-H2O+m-CO2) being within the range of 0.3 to 0.6.

## Claims

### Claim 1

Magnesium oxide powder having a coating layer consisting essentially of basic magnesium carbonate in a surface layer, when the amounts of substances of water vapor and carbon dioxide among a gas generated by thermal decomposition at 50 to 500° C. are respectively designated as m-H2O and m-CO2, in a heating evolved gas analysis of EGA-MS method, the molar fraction represented by m-CO2/(m-H2O+m-CO2) being within the range of 0.3 to 0.6, and the basic magnesium carbonate is represented by formula m-MgCO3—Mg(OH)2-nH2O in which m is an integer of 3 to 5, and n is an integer of 3 to 8.

### Claim 2

Magnesium oxide powder having a coating layer consisting essentially of basic magnesium carbonate in a surface layer, which is obtained by treating a magnesium oxide raw material, in the presence of carbon dioxide, at 30 to 45° C. and an atmosphere of relative humidity of 70 to 90% for 10 to 1000 hours, the basic magnesium carbonate being represented by formula m-MgCO3—Mg(OH)2-nH2O in which m is an integer of 3 to 5, and n is an integer of 3 to 8.

### Claim 3 (depends on 1)

The magnesium oxide powder according to claim 1, wherein the average particle size is within the range of 0.1 to 300 μm.

### Claim 4 (depends on 1)

A resin composition comprising the magnesium oxide powder as defined in claim 1.

### Claim 5

A method for producing magnesium oxide powder having a coating layer consisting essentially of basic magnesium carbonate in a surface layer, comprising treating a magnesium oxide raw material, in the presence of carbon dioxide, at 30 to 45° C. and an atmosphere of relative humidity of 70 to 90% for 10 to 1000 hours, the basic magnesium carbonate being represented by formula m-MgCO3—Mg(OH)2-nH2O in which m is an integer of 3 to 5, and n is an integer of 3 to 8.

### Claim 6 (depends on 5)

The method for producing magnesium oxide powder according to claim 5, wherein the magnesium oxide raw material has a purity of 98% or more.

### Claim 7 (depends on 2)

The magnesium oxide powder according to claim 2, wherein the average particle size is within the range of 0.1 to 300 μm.

### Claim 8 (depends on 2)

A resin composition comprising the magnesium oxide powder as defined in claim 2.