METHOD OF PREPARING AGGLOMERATED COMPOSITE MATERIALS
Metal oxide particle agglomerates prepared by adding an aluminum phosphate agglomerating agent with mixing to an aqueous dispersion of metal oxide nanoparticles to form an aqueous homogeneous dispersion of nanoparticles and agglomerating agent and then adjusting the pH of the dispersion with mixing to about 3.5 to about 6.5 to produce the particle agglomerates and use of the particle agglomerates to prepare ink receptive coatings, as catalysts, as reinforcing fillers, as polishing abrasives and as flattening agents.
1 . A method of preparing a metal oxide particle agglomerate comprising
a) adding an aluminum phosphate agglomerating agent with mixing to an aqueous dispersion of one or more metal oxide nanoparticles to form an aqueous homogeneous dispersion of nanoparticles and agglomerating agent; and
b) adjusting the pH of the dispersion with mixing to about 3.5 to about 6.5 to agglomerate the nanoparticles.
2 . The method of claim 1 wherein the nanoparticles are selected from the group consisting of silica sols, fumed silica, aluminum oxides, fumed alumina, iron oxides, zinc oxides, zirconium oxides, tin oxides, and cerium oxides.
3 . The method of claim 1 wherein the particle agglomerate has a median, d50(V), particle size of about 150 nm to about 900 nm as measured by laser light scattering.
4 . The method of claim 1 wherein the pH is adjusted to about 4 to about 6.
5 . The method of claim 4 wherein the pH is adjusted using aqueous sodium hydroxide, aqueous potassium hydroxide or aqueous ammonium hydroxide.
6 . The method of claim 4 wherein the pH is adjusted by mixing the dispersion of nanoparticles and agglomerating agent with an aqueous pH buffer solution.
7 . The method of claim 1 further comprising applying a metal oxide coating to the particle agglomerate.
8 . The method of claim 7 wherein the metal oxide coating is selected from oxides of alumina and ceria.
9 . The method of claim 2 wherein the nanoparticles are selected from the group consisting of coated and uncoated colloidal silica.
10 . The method of claim 9 wherein the coated colloidal silica is selected from the group consisting of aluminum oxide coated silica and cerium oxide coated silica.
11 . The method of claim 9 wherein the colloidal silica particles have a particle size of about 3 nm to about 150 nm as measured by quasi elastic light scattering.
12 . A method of preparing the particle agglomerate according to claim 1 comprising
a) adding an aluminum phosphate agglomerating agent with mixing to an aqueous dispersion of a mixture of nanoparticles, the mixture comprising about 99.5 to about 50 weight percent of a first nanoparticle and about 0.5 to about 50 weight percent of a second nanoparticle to form an aqueous homogeneous dispersion of nanoparticles and agglomerating agent; and
b) adjusting the pH of the dispersion with mixing to about 3.5 to about 6.5 to agglomerate the nanoparticles.
13 . The method of claim 12 wherein the first nanoparticle is selected from the group consisting of coated and uncoated colloidal silica.
14 . The method of claim 13 wherein the second nanoparticle is selected from the group consisting of silica sols, fumed silica, aluminum oxides, iron oxides, zinc oxides, zirconium oxides, tin oxides and cerium oxides.
15 . A particle agglomerate prepared according to the method of claim 1 .
16 . An ink-receptive coating for a substrate comprising one or more particle agglomerates prepared according to the method of claim 1 .
17 . The ink-receptive coating according to claim 16 wherein the particle agglomerates comprise agglomerated silica particles.
18 . Paper for use in an ink printing device comprising paper and one or more particle agglomerates prepared according to the method of claim 1 applied to the surface of the paper.
19 . A method of preparing ink jet printer paper comprising applying one or more particle agglomerates prepared according to the method of claim 1 to the surface of the paper.
20 . A catalyst support comprising one or more particle agglomerates prepared according to the method of claim 1 .
21 . A reinforcing filler composition comprising one or more particle agglomerates prepared according to the method of claim 1 .
22 . A flattening agent comprising one or more particle agglomerates prepared according to the method of claim 1 .
23 . A polishing abrasive comprising one or more particle agglomerates prepared according to claim 1 .