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CN-116761855-B - Composite particles and method for producing composite particles

CN116761855BCN 116761855 BCN116761855 BCN 116761855BCN-116761855-B

Abstract

Disclosed are composite particles comprising alumina particles and an inorganic coating layer disposed on the surface of the alumina particles. The alumina particles comprise molybdenum (Mo) and the inorganic coating layer comprises a composite metal oxide.

Inventors

  • LI MENG
  • Watake Takanori
  • YUAN JIANJUN
  • YANG SHAOWEI
  • LI XUAN
  • ZHAO WEI
  • GUO JIAN

Assignees

  • DIC株式会社

Dates

Publication Date
20260508
Application Date
20211231
Priority Date
20210113

Claims (14)

  1. 1. A composite particle comprising alumina particles and an inorganic coating layer provided on the surface of the alumina particles, the alumina particles comprising molybdenum (Mo) and silicon (Si), the inorganic coating layer comprising a composite metal oxide, The inorganic coating layer is formed of two or more layers, The composite metal oxide is a metal oxide containing two or more metals, The formation of the inorganic coating layer includes a first conversion step and a second conversion step, In the first conversion step, a first metal inorganic salt containing at least one metal other than aluminum (Al) is brought into contact with the alumina particles, and then the first metal inorganic salt deposited on the alumina particles is converted into a metal oxide, and In a second conversion step, a second metal inorganic salt is contacted with the metal oxide and/or the alumina particles, the second metal inorganic salt comprising at least one different metal other than aluminum (Al) and different from the metal used in the first conversion step, and then the metal oxide and/or the second metal inorganic salt is converted into the composite metal oxide.
  2. 2. The composite particle according to claim 1, wherein the composite metal oxide comprises a metal oxide of two or more metals selected from the group consisting of iron (Fe), titanium (Ti), zinc (Zn), nickel (Ni), cobalt (Co), manganese (Mn), and aluminum (Al).
  3. 3. The composite particle according to claim 1, wherein the composite metal oxide comprises a first metal oxide and a second metal oxide, the first metal oxide being a metal oxide of a metal selected from the group consisting of iron (Fe), titanium (Ti), zinc (Zn), nickel (Ni), and cobalt (Co), and manganese (Mn), the second metal oxide being different from the first metal oxide.
  4. 4. The composite particle of claim 1, wherein the alumina particles further comprise germanium (Ge).
  5. 5. The composite particle of claim 4, wherein the alumina particles comprise mullite in a surface layer of the alumina particles.
  6. 6. The composite particle according to any one of claims 1 to 5, wherein the composite particle has one of a sheet shape, a spherical shape, and a polyhedral shape.
  7. 7. The composite particle according to any one of claims 1 to 5, wherein the composite particle has a platelet shape, a thickness of 0.01 μm or more and 5 μm or less, an average particle diameter of 0.1 μm or more and 500 μm or less, and an aspect ratio of 2 or more and 500 or less.
  8. 8. A coating formulation, ink or shaped article comprising the composite particle according to any one of claims 1 to 7.
  9. 9. A method of producing composite particles, the method comprising the steps of: Producing alumina particles by sintering a mixture comprising an aluminum compound containing elemental aluminum, a molybdenum compound containing elemental molybdenum, and a shape control agent for controlling the shape of the alumina particles, and An inorganic coating layer containing a composite metal oxide is formed on the surface of the alumina particles, The shape controlling agent comprises one or more selected from silicon and silicon compounds containing elemental silicon, The composite metal oxide is a metal oxide containing two or more metals, Wherein the formation of the inorganic coating layer comprises a first conversion step and a second conversion step, In the first conversion step, a first metal inorganic salt containing at least one metal other than aluminum (Al) is brought into contact with the alumina particles, and then the first metal inorganic salt deposited on the alumina particles is converted into a metal oxide, and In a second conversion step, a second metal inorganic salt is contacted with the metal oxide and/or the alumina particles, the second metal inorganic salt comprising at least one different metal other than aluminum (Al) and different from the metal used in the first conversion step, and then the metal oxide and/or the second metal inorganic salt is converted into the composite metal oxide.
  10. 10. The method for producing composite particles according to claim 9, wherein the shape control agent further comprises a germanium compound containing elemental germanium.
  11. 11. The production method of the composite particle according to claim 9 or 10, wherein the mixture further comprises a potassium compound containing elemental potassium.
  12. 12. The production method of the composite particle according to claim 9, wherein the composite metal oxide comprises a metal oxide of two or more metals selected from the group consisting of iron (Fe), titanium (Ti), zinc (Zn), nickel (Ni), cobalt (Co), manganese (Mn), and aluminum (Al).
  13. 13. The production method of the composite particle according to claim 9, wherein the composite metal oxide includes a first metal oxide which is a metal oxide of a metal selected from the group consisting of iron (Fe), titanium (Ti), zinc (Zn), nickel (Ni), and cobalt (Co), and manganese (Mn), and a second metal oxide which is a metal oxide of a metal selected from the group consisting of iron (Fe), titanium (Ti), zinc (Zn), nickel (Ni), and cobalt (Co), and manganese (Mn), the second metal oxide being different from the first metal oxide.
  14. 14. The production method of the composite particle according to claim 9, wherein, in forming the inorganic coating layer, a metal inorganic salt containing at least one metal other than aluminum (Al) is brought into contact with the alumina particle, and then the metal inorganic salt deposited on the alumina particle is converted into the composite metal oxide.

Description

Composite particles and method for producing composite particles Technical Field The present invention relates to composite particles and a method for producing composite particles. In particular, the present invention relates to composite particles comprising alumina (alumina) particles provided with a coating layer (coating). Priority is claimed for international application No. pct/CN2021/071384 filed on day 131 of 2021, the contents of which are incorporated herein by reference. Background Alumina particles as inorganic fillers are used in a variety of applications. Among them, the flaky alumina particles having a high aspect ratio (aspect ratio) have particularly excellent thermal properties, optical properties, and the like, as compared with spherical alumina particles, and thus, further improvement of the performance of the flaky alumina particles is desired. In the related art, various kinds of flaky alumina particles having shape characteristics (e.g., specific main dimensions or thickness) are known, and such characteristics are designed to improve the above-mentioned inherent properties, dispersibility, and the like of the flaky alumina particles (patent documents 1 and 2). Further, a production method of controlling the shape of the flaky alumina particles to increase the aspect ratio thereof is known. Examples of the production method include a method of adding a phosphoric acid compound used as a shape control agent to perform hydrothermal synthesis (patent document 3), and a method of adding a fluorosilicate to perform firing (patent document 4). In addition, a production method of a flaky alumina in which silicon or a silicon compound containing elemental silicon is used as a crystallinity control agent in the production of the flaky alumina is known (patent document 5). As the coated alumina particles, alumina particles uniformly coated with zirconia nanoparticles on the surface are known, and alumina particles can be obtained by coating the surface of alumina particles having an average particle diameter of 0.1 μm or more with zirconia nanoparticles having an average particle diameter of 100nm or less (patent document 6). Further, as other coated particles, there is known a composite powder comprising a base powder and spherical barium sulfate particles having a number average particle diameter of 0.5 to 5.0 μm and adhering to the surface of the base powder in the form of projections, wherein the coating rate of the spherical barium sulfate particles is 10 to 70% relative to the surface area of the base powder (patent document 7). Further, as the composite oxide coated particles, blue-green pigments are known in which a substrate of a fine powder of a sheet form is coated with a metal composite oxide comprising oxides of magnesium, calcium, cobalt and titanium, the coating weight being 5 to 70 weight percent based on the total weight of the pigment, the powder being selected from among mica, talc, kaolin, sericite, synthetic mica and the like (patent document 8). In addition, other composite metal oxide coated particles are as follows. There is known a flaky alumina pigment in which a colored composite metal oxide that has reacted with a surface is present on the surface of a flaky alumina (patent document 9). There is known a wurtzite-type inorganic pigment in which, on the surface of a host particle having a wurtzite-type structure such as ZnO, znO 1-x (0 < x < 1), znS, gaN, bn, or SiC, a wurtzite-type compound having a composition different from that of the particle is present (patent document 10). [ Quotation list ] [ Patent literature ] [ Patent document 1] Japanese unexamined patent application publication No.2003-192338 [ Patent document 2] Japanese unexamined patent application publication No.2002-249315 [ Patent document 3] Japanese unexamined patent application publication No.9-59018 [ Patent document 4] Japanese unexamined patent application publication No.2009-35430 [ Patent document 5] Japanese unexamined patent application publication No.2016-222501 [ Patent document 6] Japanese unexamined patent application publication No. 2005-306535 [ Patent document 7] Japanese unexamined patent application publication No.2004-300080 [ Patent document 8] Japanese unexamined patent application publication No.4-28771 [ Patent document 9] Japanese unexamined patent application publication No.7-331110 [ Patent document 10] Japanese unexamined patent application publication No.2003-221524 Disclosure of Invention Problems to be solved by the invention However, patent documents 1 to 7 do not disclose coated alumina particles having a coating layer (coating) including a composite metal oxide. Patent document 8 states that a non-aluminum substrate is covered with a metal composite oxide containing oxides of magnesium, calcium, cobalt and titanium, wherein the coating layer weight is 5 to 70 weight percent based on the total weight of the pigment, and therefore, the resulting blue-green pigment has