A colloidal silica is disclosed that contains, with high purity, silica particles having an appropriate particle density, a high aggregation ratio, and a high alkoxy group content, and to provide a method for producing the colloidal silica in a simple manner at reduced costs. The colloidal silica containing silica particles is disclosed, wherein the silica particles have an average primary particle size of 33 nm or more, an aggregation ratio of 1.2 or more, and a particle density of 1.95 or more, the silica particles contain 1000 ppm by mass or more of alkoxy groups per gram of the silica particles, the proportion of the number of silica particles having an equivalent circle diameter under 20 nm is less than 15%, and the silica particles contain a primary amine in an amount of 5 μmol or more per gram of the silica particles.

The present invention relates to a method for producing a silica aerogel and a silica aerogel produced thereby. The present invention provides a two-step process of a nucleation step of forming silica colloid particles by using a low-concentration silica precursor and a growth step of further adding a relatively high-concentration silica precursor to form a silica wet gel by using the silica colloid particles as a seed. Thus, the present invention provides a method for producing a silica aerogel of which mechanical stability is improved to enhance pore characteristics, and physical properties are readily controllable, and also provides a silica aerogel produced thereby.

The present invention relates to a method for producing a silica aerogel and a silica aerogel produced thereby. The present invention provides a two-step process of a nucleation step of forming silica colloid particles by using a low-concentration silica precursor and a growth step of further adding a relatively high-concentration silica precursor to form a silica wet gel by using the silica colloid particles as a seed. Thus, the present invention provides a method for producing a silica aerogel of which mechanical stability is improved to enhance pore characteristics, and physical properties are readily controllable, and also provides a silica aerogel produced thereby.

Provided is a method for manufacturing an aerogel blanket, and an aerogel blanket having uniform thermal conductivity inside a substrate, wherein the method is capable of simplifying manufacturing equipment by performing gelation while rotating a substrate for a blanket into which a catalyzed sol is impregnated, improving manufacturing efficiency by controlling manufacturing time regardless of the thickness of the aerogel blanket, and improving thermal conductivity by uniformly forming aerogel in the substrate for a blanket.

Provided is a silica sol, a silica aerogel blanket using the same, and a method for manufacturing the same, wherein a hydrophobizing agent, a base catalyst, an organic solvent, and water are included in a catalyst composition when manufacturing the silica aerogel blanket, so that a wet aging step which is performed under high-temperature conditions and increases the amount of a solvent used, and a surface modification step which uses a large amount of an organic solvent and an expensive surface modifier, resulting in a process that is complex and long and thus inhibiting economic feasibility and productivity, can be omitted.

Provided is a silica sol, a silica aerogel blanket using the same, and a method for manufacturing the same, wherein a hydrophobizing agent, a base catalyst, an organic solvent, and water are included in a catalyst composition when manufacturing the silica aerogel blanket, so that a wet aging step which is performed under high-temperature conditions and increases the amount of a solvent used, and a surface modification step which uses a large amount of an organic solvent and an expensive surface modifier, resulting in a process that is complex and long and thus inhibiting economic feasibility and productivity, can be omitted.

Provided is an apparatus for preparing an aerogel blanket, the apparatus comprising: a bobbin around which a blanket is wound; a body provided with a gelling tank in which the bobbin is accommodated; a driving member configured to allow the bobbin accommodated in the gelling tank to rotate; and a silica sol supply member configured to gelate the blanket as silica sol is injected into the gelling tank to impregnate the blanket rotating by the bobbin.

Provided is an apparatus for preparing an aerogel blanket, the apparatus comprising: a bobbin around which a blanket is wound; a body provided with a gelling tank in which the bobbin is accommodated; a driving member configured to allow the bobbin accommodated in the gelling tank to rotate; and a silica sol supply member configured to gelate the blanket as silica sol is injected into the gelling tank to impregnate the blanket rotating by the bobbin.

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.

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.