Loading patent…
AssigneeUbe Material Industries, Ltd.
InventorsNaoto Nishida, Tatsuki Okutsu, Naoki Funabashi, Akira Yoshida
Estimating the term…
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.
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.
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.
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.
Dependencies are inferred from the claim text.