Embodiments of the invention include silica fiber compositions useful for treatment of animal wounds and tissue, as well as for other applications in industry. The fiber compositions may be formed via electrospinning of a sol gel produced with a silicon alkoxide reagent, such as tetraethyl ortho silicate, alcohol solvent, and an acid catalyst.

The present invention relates to a method for manufacturing a composite sheet comprising an aerogel sheet, which comprises: a step (S10) of preparing a fiber sheet (10); a step (S20) of laminating the aerogel sheet (30) on each of both surfaces of the fiber sheet (10); and a step (S30) of applying heat and a pressure to the aerogel sheet (30) and the fiber sheet (10), which are laminated, to bond the sheets to each other and to manufacture the composite sheet (40) in which the aerogel sheet (30), the fiber sheet (10), the aerogel sheet (30) are laminated.

An insulating composition containing silica particles, a resin, and a curing agent, wherein: when an aqueous solution of the silica particles having an SiO.sub.2 concentration of 3.8% by mass is heated at 121? C. for 20 hours, the amount of Na ions eluted from the silica particles is 40 ppm/SiO.sub.2 or less, especially, wherein the amount of Na ions eluted from the silica particles after the heating may be 5-38 ppm/SiO.sub.2, and, the silica particles may contain a polyvalent metal oxide so the ratio by mole of a polyvalent metal M to Si is 0.001-0.02; the mass ratio of Na.sub.2O/SiO.sub.2 in the silica particles may be 700-1,300 ppm; and the silica particles may have, on the surfaces thereof, a layer having a thickness of 0.1-1.5 nm and an Na.sub.2O/SiO.sub.2 mass ratio of 10-400 ppm, and may have an average particle diameter of 5-40 nm.

To provide modified colloidal silica capable of improving the stability of the polishing speed with time when used as abrasive grains in a polishing composition for polishing a polishing object that contains a material to which charged modified colloidal silica easily adheres, such as a SiN wafer, and to provide a method for producing the modified colloidal silica.

Modified colloidal silica, being obtained by modifying raw colloidal silica, wherein the raw colloidal silica has a number distribution ratio of 10% or less of microparticles having a particle size of 40% or less relative to a volume average particle size based on Heywood diameter (equivalent circle diameter) as determined by image analysis using a scanning electron microscope.

To provide modified colloidal silica capable of improving the stability of the polishing speed with time when used as abrasive grains in a polishing composition for polishing a polishing object that contains a material to which charged modified colloidal silica easily adheres, such as a SiN wafer, and to provide a method for producing the modified colloidal silica.

Modified colloidal silica, being obtained by modifying raw colloidal silica, wherein the raw colloidal silica has a number distribution ratio of 10% or less of microparticles having a particle size of 40% or less relative to a volume average particle size based on Heywood diameter (equivalent circle diameter) as determined by image analysis using a scanning electron microscope.

To provide modified colloidal silica capable of improving the stability of the polishing speed with time when used as abrasive grains in a polishing composition for polishing a polishing object that contains a material to which charged modified colloidal silica easily adheres, such as a SiN wafer, and to provide a method for producing the modified colloidal silica.

Modified colloidal silica, being obtained by modifying raw colloidal silica, wherein

the raw colloidal silica has a number distribution ratio of 10% or less of microparticles having a particle size of 40% or less relative to a volume average particle size based on Heywood diameter (equivalent circle diameter) as determined by image analysis using a scanning electron microscope.

To provide modified colloidal silica capable of improving the stability of the polishing speed with time when used as abrasive grains in a polishing composition for polishing a polishing object that contains a material to which charged modified colloidal silica easily adheres, such as a SiN wafer, and to provide a method for producing the modified colloidal silica.

Modified colloidal silica, being obtained by modifying raw colloidal silica, wherein

the raw colloidal silica has a number distribution ratio of 10% or less of microparticles having a particle size of 40% or less relative to a volume average particle size based on Heywood diameter (equivalent circle diameter) as determined by image analysis using a scanning electron microscope.

A method for producing a micron-size spherical silica aerogel having a selectable or controllable average particle size, the method includes producing a surface-modified silica sol by adding a first organosilane compound to a aqueous acid-silica sol, which comprises an inorganic acid and a water glass solution, with a pH less than 3, dispersive mixing a non-polar organic solvent, a second organosilane compound, and the surface-modified silica sol, at a selected stilling rate which is inversely related to an average particle size, without adding any surfactant or dispersant, a micron-size spherical silica hydrogel and further a hydrophobic micron-size spherical silica gel are then produced. Following by drying or stirring the hydrophobic micron-size spherical silica gel to obtain a controllable micron-size silica aero-gel in a spherical and powder forms, respectively.

A method for producing a micron-size spherical silica aerogel having a selectable or controllable average particle size, the method includes producing a surface-modified silica sol by adding a first organosilane compound to a aqueous acid-silica sol, which comprises an inorganic acid and a water glass solution, with a pH less than 3, dispersive mixing a non-polar organic solvent, a second organosilane compound, and the surface-modified silica sol, at a selected stilling rate which is inversely related to an average particle size, without adding any surfactant or dispersant, a micron-size spherical silica hydrogel and further a hydrophobic micron-size spherical silica gel are then produced. Following by drying or stirring the hydrophobic micron-size spherical silica gel to obtain a controllable micron-size silica aero-gel in a spherical and powder forms, respectively.

Embodiments of the invention include silica fiber compositions useful for treatment of animal wounds and tissue, as well as for other applications in industry. The fiber compositions may be formed via electrospinning of a sol gel produced with a silicon alkoxide reagent, such as tetraethyl ortho silicate, alcohol solvent, and an acid catalyst.