Disclosed is a coating composition which includes: polyurethane; and amphiphilic silica nanoparticles having an amine functional group and a fluorine functional group in their structure. Further provided are a polyurethane-silica composite film including the coating composition and a method of preparing the same.

Hollow nanoparticles for time-release delivery of a payload. A composition include a mesoporous hollow nanoparticle and a degradation agent, wherein the degradation agent includes one or more of a reducing agent, an acid, or an acidifier. The mesoporous hollow nanoparticle degrades in a presence of the degradation agent for time-release of a payload.

A silica-blended resin varnish contains a silica sol with a high dispersibility that is dispersed in a ketone organic solvent, in a nitrogen atom-containing polymer. The particles have an average size of 5 to 100 nm and have a carbon-carbon unsaturated bond-containing organic group and an alkoxy group bonded to surfaces thereof. The carbon-carbon unsaturated bond-containing organic group is bonded at 0.5 to 2.0 groups per unit area (nm.sup.2) of the particle surfaces. The alkoxy group is bonded at 0.1 to 2.0 groups per unit area (nm.sup.2) of the particle surfaces. The molar ratio of {(the carbon-carbon unsaturated bond-containing organic group)/(the alkoxy group)} is 0.5 to 5.0. The carbon-carbon unsaturated bond-containing organic group may be a phenyl group-containing organic group or a (meth)acryloyl group-containing organic group. An insulating resin composition contains the silica sol and a nitrogen-containing polymer, which may be polyimide, polyamide, polyamic acid, polyamide-imide, polyetherimide, or polyesterimide.

The invention relates to a process for the preparation of a novel precipitated silica, wherein: a silicate is reacted with an acidifying agent, so as to obtain a silica suspension; said silica suspension is filtered, so as to obtain a filter cake; said filter cake is subjected to a liquefaction operation, in the absence of an aluminium compound; wherein a mixture of polycarboxylic acids is added to the filter cake, during or after the liquefaction operation. It also relates to novel precipitated silicas and to their uses.

The invention relates to a process for preparing a precipitated silica, to precipitated silicas, and to uses thereof. The process of the invention generally includes reacting a silicate with an acidifying agent, so as to obtain a suspension of precipitated silica; filtering the precipitated silica to obtain a filter cake; subjecting the filter cake to a liquefaction operation to form a second filter cake; and drying the second filter cake. In the process of the invention, at least one polycarboxylic acid is added to the filter cake, during or after the liquefaction operation.

The present invention provides a surface-treated silica filler for suppressing an increase in viscosity when added to a resin composition used for applications such as a semiconductor sealing material, and the resin composition containing the surface-treated silica filler. The surface-treated silica filler of the present invention is surface-treated with a basic substance having an acid dissociation constant (pKa) of its conjugate acid of 9.4 or more.

A method for producing a paint color material developing a color by a pigmentary color and a structural color, the method including: obtaining a mixed liquid containing a color material particles by alternately adding and mixing a liquid obtained by suspending core particles each having a uniform particle diameter in a solution containing Fe and a liquid containing tannic acid into a liquid containing water as a main component, the color material particles each comprising a core portion formed by the core particle and a pigmentary layer that is formed around the core portion and contains an iron tannate, and each having a particle diameter corresponding to a wavelength of the structural color; and washing the color material particles, in which a pH of the mixed liquid is adjusted to 7.0 or more prior to the second step, and the pH is adjusted in order to obtain any color

A silicate-coated body contains: a mica particle; a first silicate coating at least part of the mica particle; and a functional substance that is carried by the first silicate.

Problem: To provide highly water-repellent layered silicate-coated silica particles with higher safety.

Solution: A layered silicate-coated body has a silica particle, a saponite-like layered silicate derivative coating at least part of the silica particle, and a hydrophobic functional group introduced to the silica particle and/or the layered silicate derivative.

Aqueous dispersion containing a hydrophilic metal oxide powder comprising a metal oxide and a surface modification of the metal oxide, wherein a) the metal oxide is selected from the group consisting of TiO.sub.2, ZrO.sub.2, SiO.sub.2, Al.sub.2O.sub.3, Fe.sub.2O.sub.3, Fe.sub.3O.sub.4, Sb.sub.2O.sub.3, WO.sub.3, CeO.sub.2 and mixed oxides thereof and b) the surface modification b1) comprises silicon atoms and aluminum atoms and b2) the silicon atoms are at least partly bonded to a hydrocarbon radical via a C atom and b3) the Al/Si molar ratio of the surface modification is 1:2-1:20.