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CN-119894824-B - Hollow silica sol containing 1-valent alkali metal ion and method for producing same

CN119894824BCN 119894824 BCN119894824 BCN 119894824BCN-119894824-B

Abstract

The present invention relates to an aqueous sol and an organic solvent sol containing hollow silica particles having high stability, and further relates to a method for improving the stability of the sol having reduced storage stability, and a method for producing the same. To this end, there is provided a hollow silica sol containing hollow silica particles having a space in the interior of a shell and 1-valent alkali metal ions, wherein the hollow silica particles and 1-valent alkali metal ions are contained in such a manner that the molar number of the 1-valent alkali metal ions converted to M 2 O (M represents 1-valent alkali metal atoms) relative to the molar number of SiO 2 of the hollow silica particles is 7.12X10- ‑6 ～285×10 ‑6 , and the sol has an average particle diameter measured by a dynamic light scattering method after storage at 50 ℃ for 48 hours, which is within a range of 2.0 times or less as compared with the average particle diameter measured by a dynamic light scattering method before storage. The average particle size measured by a dynamic light scattering method is 20-150 nm. A stabilization method wherein a 1-valent alkali metal ion is added to a hollow silica sol having an increased particle diameter value by a dynamic light scattering method in such a manner that the 1-valent alkali metal ion is in the above ratio to SiO 2 of hollow silica particles in the hollow silica sol, thereby decreasing the increased particle diameter value by a dynamic light scattering method.

Inventors

  • EBARA KAZUYA
  • ZHONG TIANHAO
  • NISHIMURA TORU
  • Xiaji Zhenzhen

Assignees

  • 日产化学株式会社

Dates

Publication Date
20260505
Application Date
20240726
Priority Date
20230728

Claims (20)

  1. 1. A hollow silica sol comprising hollow silica particles having a space in the interior of a shell and 1-valent alkali metal ions, The hollow silica particles and the 1-valent alkali metal ions are contained in such a manner that the molar amount of the 1-valent alkali metal ions converted to M 2 O relative to the molar amount of SiO 2 of the hollow silica particles is 7.12X10 -6 ～285×10 -6 , wherein M represents a 1-valent alkali metal atom, The average particle diameter of the sol measured by a dynamic light scattering method after being stored at 50 ℃ for 48 hours is within a range of 2.0 times or less than the average particle diameter measured by a dynamic light scattering method before the storage, The 1-valent alkali metal ion is lithium ion, sodium ion and/or potassium ion.
  2. 2. The hollow silica sol of claim 1, wherein the 1-valent alkali metal ion is sodium ion.
  3. 3. The hollow silica sol according to claim 1 or 2, wherein the average particle diameter measured by a dynamic light scattering method is 20 to 150nm.
  4. 4. The hollow silica sol according to claim 1 or 2, further comprising an amine, wherein the amine accounts for 0.001 to 10 mass% of the SiO 2 of the hollow silica particles.
  5. 5. The hollow silica sol according to claim 4, wherein the amine is at least one amine selected from primary amine, secondary amine and tertiary amine having 1 to 10 carbon atoms.
  6. 6. The hollow silica sol according to claim 4, wherein the amine is a water-soluble amine having a water solubility of 80g/L or more.
  7. 7. The hollow silica sol according to claim 1, wherein the hollow silica particles contain aluminum atoms forming aluminosilicate sites, The aluminum atoms are bonded to the surfaces of the hollow silica particles, The mass of the aluminum atom is in the range of 100 to 20000ppm in terms of Al 2 O 3 relative to the mass of SiO 2 of the hollow silica particles, The atomic mass of aluminum is a value measured by a leaching method.
  8. 8. The hollow silica sol according to claim 7, wherein an aqueous solution of at least one mineral acid selected from sulfuric acid, nitric acid and hydrochloric acid is used in the measurement of the leaching method for leaching aluminum atoms from a compound containing aluminum atoms bonded to surfaces of hollow silica particles.
  9. 9. The hollow silica sol according to claim 7 or 8, wherein the mass of aluminum atoms present in the whole hollow silica particles is represented by a ratio B of 120 to 50000ppm in terms of Al 2 O 3 to the mass of SiO 2 of the hollow silica particles, The mass of the aluminum atoms is a value obtained by dissolving hollow silica particles in an aqueous hydrofluoric acid solution, The ratio A/the ratio B is 0.002-1.0.
  10. 10. The hollow silica sol according to claim 1 or 2, wherein the hollow silica particles have a ratio of [ specific surface area C of silica particles obtained by BET method, i.e., nitrogen adsorption method ]/[ specific surface area D of silica particles converted by transmission electron microscope ] of 1.40 to 5.00.
  11. 11. The hollow silica sol according to claim 1 or 2, wherein the hollow silica particles contain hollow silica particles having a surface charge amount of 5 to 250 μeq/g per 1g in terms of SiO 2 .
  12. 12. The hollow silica sol according to claim 1 or 2, further comprising hollow silica particles coated with at least one silane compound selected from the group consisting of the compound represented by the following formula (1) and the compound represented by the formula (2), In the formula (1), the components are as follows, R 1 is a group bonded to a silicon atom, independently of one another, represents an alkyl group, a haloalkyl group, an alkenyl group, an aryl group, or an organic group having an epoxy group, a (meth) acryloyl group, a mercapto group, a amino group, a ureido group, a polyether group, a carboxyl group, a protected carboxyl group, a carboxyl group generating group, an imide group, or a cyano group and bonded to a silicon atom through a Si-C bond, or represents a combination of these groups, R 2 is a group or an atom bonded to a silicon atom, and independently represents an alkoxy group having 1 or more carbon atoms, an acyloxy group, a hydroxyl group, or a halogen atom, or a combination of these groups, A represents an integer of 1 to 3, In the formula (2), the amino acid sequence of the compound, R 3 is a group bonded to a silicon atom, independently of one another, represents an alkyl group, a haloalkyl group, an alkenyl group, an aryl group, or represents an organic group having an epoxy group, a (meth) acryl group, a mercapto group, an amino group, a ureido group, a polyether group, a carboxyl group, a protected carboxyl group, a carboxyl group generating group, an imide group or a cyano group and bonded to a silicon atom through a Si-C bond, or represents a combination of these groups, R 4 is a group or an atom bonded to a silicon atom, and independently represents an alkoxy group having 1 or more carbon atoms, an acyloxy group, a hydroxyl group, or a halogen atom, or a combination of these groups, Y is a group or atom bonded to a silicon atom, represents an alkylene group, an NH group or an oxygen atom, B represents an integer of 1 to 3, and c represents an integer of 0 or 1.
  13. 13. The hollow silica sol according to claim 1 or 2, wherein the dispersion medium is water, an alcohol having 1 to 10 carbon atoms, a ketone, an ether, an amide, urea or an ester.
  14. 14. A composition for forming a coating film comprising Hollow silica particles derived from the hollow silica sol of any one of claims 1 to 13, and An organic resin or a polysiloxane.
  15. 15. A film having a visible light transmittance of 80% or more, which is obtained from the composition for forming a film according to claim 14.
  16. 16. The method for producing a hollow silica sol according to any one of claims 1 to 13, comprising the following steps (I) to (II): (I) A step of preparing a hollow silica sol containing a dispersion medium, And (II) adding 1-valent alkali metal ions to the hollow silica sol of the step (I), wherein the 1-valent alkali metal ions are lithium ions, sodium ions and/or potassium ions, and the molar ratio of the 1-valent alkali metal ions to SiO 2 of the hollow silica particles is 7.12X10 -6 ～285×10 -6 , wherein M in M 2 O represents a 1-valent alkali metal atom, by converting the 1-valent alkali metal ions to M 2 O.
  17. 17. The method for producing a hollow silica sol according to claim 16, wherein in the step (II), the 1-valent alkali metal ion is sodium ion.
  18. 18. The method for producing a hollow silica sol according to claim 17, wherein in the step (II), the sodium ion content is adjusted by bringing the hollow silica sol obtained in the step (I) into contact with a cation exchange resin or adding a sodium source.
  19. 19. The method for producing a hollow silica sol according to claim 17, wherein in the step (II), the sodium source is added with sodium hydroxide.
  20. 20. The method according to any one of claims 16 to 19, wherein the dispersion medium in the steps (I) and (II) is water, an alcohol having 1 to 10 carbon atoms, a ketone, an ether, an amide, urea or an ester.

Description

Hollow silica sol containing 1-valent alkali metal ion and method for producing same Technical Field The present invention relates to a sol in which hollow silica particles containing 1-valent alkali metal ions such as sodium ions are dispersed in water or an organic solvent, a method for producing the same, and a composition for forming a coating film. Background Hollow silica particles having a silica shell and a space inside the shell are characterized by having low refractive index, low thermal conductivity (heat insulation), electrical insulation, and the like. The hollow silica particles are composed of a core corresponding to the hollow portion and a shell forming the outside of the core, and an aqueous dispersion of the hollow silica particles is obtained by a method in which a silica layer is formed on the outside of the core in an aqueous medium and then the core is removed. Silica-based particles having voids in the interior of a shell, characterized in that the average particle diameter is in the range of 5 to 500nm, the refractive index is in the range of 1.15 to 1.38, the molar ratio MO X/SiO2 of inorganic oxides other than silica represented by MO X is in the range of 0.0001 to 0.2 when silica is represented by SiO 2, and the content of alkali metal oxides is 5ppm or less in terms of A 2 O (A: alkali metal element) (see patent document 1). Also disclosed is a silica-based particulate having a porous substance and/or voids in the interior of a shell layer, wherein the ratio (SB/SC) of the specific surface area (SB) of the particulate to the specific surface area (SC) represented by the following formula, as measured by the BET method, is in the range of 1.1 to 5, the refractive index is in the range of 1.15 to 1.38, the content of an alkali metal oxide is 5ppm or less in terms of M 2 O (M: alkali metal element) relative to the silica-based particulate, and the content of ammonia and/or ammonium ions is 1500ppm or less in terms of NH 3 relative to the silica-based particulate (see patent document 2). SC(m2/g)=6000/Dp(nm)·ρ (Wherein Dp: average particle diameter (nm) of silica-based particles, ρ: density (g/ml)) Prior art literature Patent literature Patent document 1 Japanese patent laid-open publication 2011-046606 Patent document 2 Japanese patent application laid-open No. 2013-121911 Disclosure of Invention Problems to be solved by the invention The present invention relates to an aqueous sol and an organic solvent sol containing hollow silica particles having high stability, and further relates to a method for improving the stability of the sol having reduced storage stability, and a method for producing the same. Means for solving the problems The present invention is, as an aspect 1, a hollow silica sol containing hollow silica particles having a space in the interior of a shell and 1-valent alkali metal ions, The hollow silica particles and the 1-valent alkali metal ions are contained in such a manner that the molar amount of the 1-valent alkali metal ions converted to M 2 O relative to the molar amount of SiO 2 of the hollow silica particles is 7.12X10 -6～285×10-6, wherein M represents a 1-valent alkali metal atom, The average particle diameter of the sol measured by a dynamic light scattering method after being stored at 50 ℃ for 48 hours is within a range of 2.0 times or less as compared with the average particle diameter measured by a dynamic light scattering method before the storage. Or a hollow silica sol containing hollow silica particles having a space in the interior of a shell and 1-valent alkali metal ions, wherein the hollow silica particles and the 1-valent alkali metal ions are contained in such a manner that the molar ratio of the 1-valent alkali metal ions to SiO 2 of the hollow silica particles is 7.12X10 -6～285×10-6 after conversion to M 2 O, wherein M represents a 1-valent alkali metal atom, and the dynamic light scattering method particle diameter of the sol after storage at 50 ℃ for 48 hours is within a range of 2.0 times or less than that before storage. As viewpoint 2, the hollow silica sol according to viewpoint 1, wherein the 1-valent alkali metal ion is sodium ion. As aspect 3, the hollow silica sol according to aspect 1 or 2 has an average particle diameter of 20 to 150nm as measured by a dynamic light scattering method. In view 4, the hollow silica sol according to any one of views 1 to 3, further comprising an amine, wherein the amine accounts for 0.001 to 10 mass% of SiO 2 of the hollow silica particles. As the aspect 5, the hollow silica sol according to the aspect 4, wherein the amine is at least one amine selected from primary amine, secondary amine and tertiary amine having 1 to 10 carbon atoms. In view 6, the hollow silica sol according to view 4 or 5, wherein the amine is a water-soluble amine having a water solubility of 80g/L or more. In view 7, the hollow silica sol according to any one of views 1 to 6, further comprising aluminum atoms forming alu