Silica coating for enhanced hydrophilicity
Assignee3M Innovation Properties Company
InventorsPatrick J. Hager, Jay S. Schlechte, Elaine M. Yorkgitis, Naiyong Jing
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Abstract
A coating composition is provided comprising a) an aqueous dispersion, having a pH of less than 7.5, of silica nanoparticles having average particle diameters of 40 nanometers or less, b) an alkoxysilane oligomer; c) a silane coupling agent, and d) optionally a metal β-diketone complexing agent. The compositions may be used to prepare coated articles wherein the coating is substantially uniform in thickness, durably adheres to the substrate, and provides hydrophilic and/or antireflection surface properties to the substrate.
Claims19
A coating composition having a pH of less than 7.5 comprising:
- a) an aqueous dispersion, of 50 to 74 wt. % of silica nanoparticles having average particle diameters of 40 nanometers or less, based on total solids of the coating composition;
- b) 25 to 49 wt %, based on total solids of the coating composition, of a mixture of linear and branched alkoxysilane oligomers of the formula:
- where
- each R1 is individually H, C1 to C4 alkyl, an alkali metal, and earth metal or ammonium;
- each R2 is independently C1 to C4 alkyl,
- x is 2 to 100,
- y and z may be zero,
- x is greater than y+z;
- and
- x+y+z is 2 to 100;
- c) 0.25 to 24 wt. %, based on total solids of the coating composition, of a silane coupling agent, and
- d) 0 to 10 wt. %, based on total solids of the coating composition, of a metal β-diketone complexing agent;
- when cured, transmits at least 85% of incident light in the range of 400-700 nm.
Dependencies are inferred from the claim text.