A composition for forming a transparent coating film including hollow silica microparticles and a binder is provided. The hollow silica microparticles have an average particle diameter of 5 to 300 nm when measured by the dynamic light scattering method, a specific surface area of 50 to 1500 m.sup.2/g, and an outer shell in which cavities are formed. The microparticles lose weight by 1.0 W % or more at a temperature in the range of from 200° C. to 500° C. when measured by the thermogravimetry (TG). A surface charge (QA) of the hollow silica microparticles contained in the compositions for forming a transparent coating film is in the range from 5 to 20 μeq/g.

A composition for forming a transparent coating film including hollow silica microparticles and a binder is provided. The hollow silica microparticles have an average particle diameter of 5 to 300 nm when measured by the dynamic light scattering method, a specific surface area of 50 to 1500 m.sup.2/g, and an outer shell in which cavities are formed. The microparticles lose weight by 1.0 W % or more at a temperature in the range of from 200° C. to 500° C. when measured by the thermogravimetry (TG). A surface charge (QA) of the hollow silica microparticles contained in the compositions for forming a transparent coating film is in the range from 5 to 20 μeq/g.

The present invention provides a method for producing an aerogel, comprising a sol generating step of generating, by hydrolyzing a silane oligomer, a sol containing a hydrolysis product of the silane oligomer; a wet gel generating step of obtaining a wet gel by gelation of the sol; and a drying step of drying the wet gel to obtain an aerogel, wherein a proportion of silicon atoms each bonded to three oxygen atoms in a total number of silicon atoms contained in the silane oligomer is 50% or more.

The present invention provides a method for producing an aerogel, comprising a sol generating step of generating, by hydrolyzing a silane oligomer, a sol containing a hydrolysis product of the silane oligomer; a wet gel generating step of obtaining a wet gel by gelation of the sol; and a drying step of drying the wet gel to obtain an aerogel, wherein a proportion of silicon atoms each bonded to three oxygen atoms in a total number of silicon atoms contained in the silane oligomer is 50% or more.

Porous silica-carbon composites are obtained by mixing fine particulate carbon dispersed in water by a surfactant, alkali metal silicate aqueous solution, and mineral acid so as to produce co-dispersion in which silica hydrosol, produced by reaction of the alkali metal silicate and the mineral acid, and the fine particulate carbon are uniformly dispersed, and gelling silica hydrosol, contained in the co-dispersion, and making the co-dispersion into porous bodies. The porous silica-carbon composites are prepared so as to have specific surface area from 20 to 1000 m.sup.2/g, pore volume from 0.3 to 2.0 ml/g, and average pore diameter from 2 to 100 nm.

Porous silica-carbon composites are obtained by mixing fine particulate carbon dispersed in water by a surfactant, alkali metal silicate aqueous solution, and mineral acid so as to produce co-dispersion in which silica hydrosol, produced by reaction of the alkali metal silicate and the mineral acid, and the fine particulate carbon are uniformly dispersed, and gelling silica hydrosol, contained in the co-dispersion, and making the co-dispersion into porous bodies. The porous silica-carbon composites are prepared so as to have specific surface area from 20 to 1000 m.sup.2/g, pore volume from 0.3 to 2.0 ml/g, and average pore diameter from 2 to 100 nm.

Provided is an inorganic oxide dispersion (sol) in which inorganic oxide particles are dispersed in silicone oil.

Provided is an inorganic oxide dispersion (sol) in which inorganic oxide particles are dispersed in silicone oil.

A hydrophobic treatment method is used in which at least one sheet filled with a gelled silicic acid is tilted at least two degrees with respect to a horizontal direction in a hydrophobizing solution, and the gelled silicic acid is hydrophobized. A manufacturing method for a sheet-like member is also used. The manufacturing method includes: a sol preparing step of adjusting the pH of a water glass aqueous solution to obtain a sol solution of silicic acid; an adding step of adding the sol solution to a fiber; a gel step of polymerizing and gelling the sol solution; a hydrophobic treatment step of hydrophobizing the gel with the hydrophobic treatment method; and a drying step of drying the hydrophobized gel.

A hydrophobic treatment method is used in which at least one sheet filled with a gelled silicic acid is tilted at least two degrees with respect to a horizontal direction in a hydrophobizing solution, and the gelled silicic acid is hydrophobized. A manufacturing method for a sheet-like member is also used. The manufacturing method includes: a sol preparing step of adjusting the pH of a water glass aqueous solution to obtain a sol solution of silicic acid; an adding step of adding the sol solution to a fiber; a gel step of polymerizing and gelling the sol solution; a hydrophobic treatment step of hydrophobizing the gel with the hydrophobic treatment method; and a drying step of drying the hydrophobized gel.