There is provided a method of manufacturing silica microspheres includes the steps of mixing acid and water to form a mixture; adding a silicon alkoxide to the mixture so as to precipitate microspheres; allowing the microspheres to settle into a sediment and removing a supernatant liquid; and immersing the microspheres in acid.

There is provided a method of manufacturing silica microspheres includes the steps of mixing acid and water to form a mixture; adding a silicon alkoxide to the mixture so as to precipitate microspheres; allowing the microspheres to settle into a sediment and removing a supernatant liquid; and immersing the microspheres in acid.

A precipitated silica characterised by the presence of specific acid sites on its surface and a process for its manufacture.

A precipitated silica characterised by the presence of specific acid sites on its surface and a process for its manufacture.

A precipitated silica suitable for thermal insulation applications and a process for its manufacture.

A precipitated silica suitable for thermal insulation applications and a process for its manufacture.

The present invention relates to a hydrous silica for rubber reinforcing fillers having CTAB specific surface area in the range of 220 to 350 m.sup.2/g and a pore volume over the range of pore radius 1.9 to 100 nm measured by mercury press-in method in the range of 1.7 to 2.0 cm.sup.3/g, wherein a volume average particle diameter D50 in a volume particle size distribution measured by laser diffraction method for the slurry obtained by dispersing 50 ml of a hydrous silica slurry adjusted to 4 mass % with an ultrasonic homogenizer at an output of 140 W for 10 minutes is in the range of 5.0 to 12.0 μm, and a cumulative value of hydrous silica particles over the range of 4.0 to 35.0 μm in the volume particle size distribution is 80% or more. The present invention also relates to a rubber composition containing the above-mentioned hydrous silica and a rubber component containing a natural rubber. The present invention provides a hydrous silica which has equivalent or excellent reinforcing property (abrasion resistance, tensile strength) and which allows to greatly reduce the rolling resistance when it is blended into a rubber based on the natural rubber for TBRs, which is often used under a heavy load, compared with conventional hydrous silicas, and provides the rubber composition containing the hydrous silica.

Spherical silica and/or silicate particles having a d50 median particle size from 1 to 5 μm, a d95 particle size less than 8 μm, an oil absorption from 40 to 100 cc/100 g, a pack density from 20 to 60 lb/ft.sup.3, and a sphericity factor (S.sub.80) of at least 0.9, are disclosed, as well as methods for making these spherical particles, and dentifrice compositions containing the spherical particles.

Spherical silica and/or silicate particles having a d50 median particle size from 1 to 5 μm, a d95 particle size less than 8 μm, an oil absorption from 40 to 100 cc/100 g, a pack density from 20 to 60 lb/ft.sup.3, and a sphericity factor (S.sub.80) of at least 0.9, are disclosed, as well as methods for making these spherical particles, and dentifrice compositions containing the spherical particles.

The present invention relates to hollow silica particles, which each includes a shell layer containing silica and a space inside the shell layer, in which the hollow silica particles have a peak intensity derived from SiOH at a wavenumber of around 3,746 cm.sup.−1 of 0.60 or less by infrared spectroscopy, a relative permittivity at 1 GHz of from 1.3 to 5.0 and a dielectric loss tangent at 1 GHz of from 0.0001 to 0.05.