Silica aerogel-including blanket and method for preparing the same
The present disclosure provides a silica aerogel-including blanket including a substrate for a blanket; and a silica aerogel and an opacifying agent locating at least one of on a surface of and inside the substrate for a blanket, wherein the opacifying agent is a second particulate with inorganic particles of a first particulate being aggregated, and includes 1 to 5 of the inorganic particles per unit volume of 1 μm 3 , and a method for preparing the same. The silica aerogel-including blanket according to the present disclosure is capable of exhibiting flame retardancy as well as an excellent insulation property, particularly, an excellent insulation property at high temperatures, by including an opacifying agent having excellent dispersibility and high surface activity through chemical etching.
1. A method for preparing a silica aerogel-including blanket, the method comprising:
preparing an opacifying agent-including dispersion liquid by dispersing inorganic particles into an aqueous basic solution and etching the inorganic particles to form an opacifying agent, and then adding water thereto;
preparing an opacifying agent-including composition for forming a silica aerogel by mixing the opacifying agent-including dispersion liquid with a silica precursor;
preparing an opacifying agent-silica gel-substrate complex by adding a base catalyst and a polar organic solvent to the opacifying agent-including composition for forming a silica aerogel, and then adding a substrate for a blanket thereto and gelling the opacifying agent-including composition; and
surface hydrophobizing the opacifying agent-silica gel-substrate complex and then drying a surface hydrophobized opacifying agent-silica gel-substrate complex.
2. The method for preparing a silica aerogel-including blanket of claim 1 , wherein the opacifying agent is a second particulate having a structure formed by aggregation of inorganic particles of a first particulate being aggregated, and includes 1 to 5 of the inorganic particles per unit volume of 1 μm 3 .
3. The method for preparing a silica aerogel-including blanket of claim 2 , wherein the second particulate has an average particle diameter of 300 nm to 600 nm and the first particulate has an average particle diameter of 100 nm to 300 nm.
4. The method for preparing a silica aerogel-including blanket of claim 1 , wherein the aqueous basic solution includes water and a strong base having an acid dissociation constant of 12 or greater.
5. The method for preparing a silica aerogel-including blanket of claim 1 , wherein the etching is carried out for a period of time required for the opacifying agent in the finally prepared opacifying agent-including dispersion liquid to exhibit average zeta-potential of −10 mV to −60 mV after dispersing the inorganic particles into the aqueous basic solution including a strong base having an acid dissociation constant of 12 or greater in a concentration of 0.1 M to 10 M.
6. The method for preparing a silica aerogel-including blanket of claim 1 , wherein the surface modification of hydrophobization is carried out using a silazane-based surface modifier including two or more alkyl group in the molecule.