| CPC C01B 33/126 (2013.01) [B82Y 30/00 (2013.01); B82Y 40/00 (2013.01); C01P 2004/03 (2013.01); C01P 2004/64 (2013.01)] | 16 Claims |
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1. A metal oxide particle having a surface modified with a silyl group and having an aggregation ratio (average particle size measured by dynamic light scattering/average diameter of primary particles measured in an SEM image) of 5.0 or less,
an isoelectric point of a colloidal aqueous dispersion of the metal oxide particles being at least pH 10.8, the colloidal aqueous dispersion having a solids concentration of the metal oxide particles of 2 wt %,
the silyl group being at least one group selected from the group consisting of a silyl group represented by general formula (1):
—Si(X)n-[L-CR1(OH)—C(R2)2-A]3-n (1),
wherein
X is the same or different, and each represents a hydroxy group, a hydrolyzable substituent, a non-hydrolyzable substituent, a bond with Si of another silyl group via —O—, or a bond with a metal atom on the particle surface via —O—;
n is 0, 1, or 2;
L is a linkage group;
R1 is a hydrogen atom, or an alkyl group that may contain an amino group, a hydroxy group, or an unsaturated bond;
R2 is the same or different, and each represents a hydrogen atom, or an alkyl group that may contain an amino group, a hydroxy group, or an unsaturated bond; and
A is a quaternary ammonium group, and
a silyl group represented by general formula (2):
![]() wherein
X′ is the same or different, and each represents a hydroxy group, a hydrolyzable substituent, a non-hydrolyzable substituent, a bond with Si of another silyl group via —O—, or a bond with a metal atom on the particle surface via —O—;
n′ is 0, 1, or 2;
L′ is a linkage group; and
A′ is a quaternary ammonium group.
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