There is provided a method of producing silica capsules, the method comprising: adding a silica precursor to emulsified droplets in the presence of salt and alcohol to enhance silica growth around the emulsified droplets by an ion association effect, thereby forming silica capsules. Also provided are silica capsules producible by such a method.

The present invention relates to a silica sol having a pH above about 10, molar ratio of SiO2:M2O, in which M is alkali metal, of from about 6:1 to about 16:1, concentration of soluble silica above about 3000 mg SiO2/l, and S-value of from about 18 to about 40%. The invention further relates to a process for producing a silica sol which comprises acidifying an aqueous alkali metal silicate solution to a pH of from 1 to 4 to form an acid sol, alkalizing the acid sol by addition of aqueous alkali metal silicate solution to obtain an intermediate sol and interrupt the addition of aqueous alkali metal silicate solution when the intermediate sol has reached a pH of from about 5 to about 8, stirring the intermediate sol for a time period of from about 10 to about 6000 seconds without addition of aqueous alkali metal silicate solution, alkalizing the intermediate sol by addition of aqueous alkali metal silicate solution to obtain a silica sol having a pH above about 10 and molar ratio of SiO2:M2O, in which M is alkali metal, of from about 6:1 to about 16:1, and optionally adding an aluminum compound to the acid sol, intermediate sol or silica sol. The invention further relates to a silica sol obtainable by the process of the invention. The invention further relates to the use of the silica sol as a flocculating agent, in water purification and in producing paper and board. The invention further relates to a process for producing paper and board which comprises: (i) providing an aqueous suspension comprising cellulosic fibers; (ii) adding to the suspension one or more drainage and retention aids comprising the silica sol; and (iii) dewatering the obtained suspension to provide a sheet or web of paper or board.

The present invention relates to a silica sol having a pH above about 10, molar ratio of SiO2:M2O, in which M is alkali metal, of from about 6:1 to about 16:1, concentration of soluble silica above about 3000 mg SiO2/l, and S-value of from about 18 to about 40%. The invention further relates to a process for producing a silica sol which comprises acidifying an aqueous alkali metal silicate solution to a pH of from 1 to 4 to form an acid sol, alkalizing the acid sol by addition of aqueous alkali metal silicate solution to obtain an intermediate sol and interrupt the addition of aqueous alkali metal silicate solution when the intermediate sol has reached a pH of from about 5 to about 8, stirring the intermediate sol for a time period of from about 10 to about 6000 seconds without addition of aqueous alkali metal silicate solution, alkalizing the intermediate sol by addition of aqueous alkali metal silicate solution to obtain a silica sol having a pH above about 10 and molar ratio of SiO2:M2O, in which M is alkali metal, of from about 6:1 to about 16:1, and optionally adding an aluminum compound to the acid sol, intermediate sol or silica sol. The invention further relates to a silica sol obtainable by the process of the invention. The invention further relates to the use of the silica sol as a flocculating agent, in water purification and in producing paper and board. The invention further relates to a process for producing paper and board which comprises: (i) providing an aqueous suspension comprising cellulosic fibers; (ii) adding to the suspension one or more drainage and retention aids comprising the silica sol; and (iii) dewatering the obtained suspension to provide a sheet or web of paper or board.

Provided is a method for manufacturing an aerogel blanket having improved processability by reducing manufacturing time and cost, the method including the steps of mixing a precursor material, an acid catalyst and a hydrous alcohol to prepare a sol, depositing a substrate in the sol, and reacting with a gaseous silazane-based compound to form a gel and to perform aging and surface modification reaction simultaneously to form a wet gel blanket, and drying the wet gel blanket to manufacture an aerogel blanket.

Provided is a method for manufacturing an aerogel blanket having improved processability by reducing manufacturing time and cost, the method including the steps of mixing a precursor material, an acid catalyst and a hydrous alcohol to prepare a sol, depositing a substrate in the sol, and reacting with a gaseous silazane-based compound to form a gel and to perform aging and surface modification reaction simultaneously to form a wet gel blanket, and drying the wet gel blanket to manufacture an aerogel blanket.

A production method for an aerogel includes a sol generation step by adding a silicon compound to an aqueous solution containing an acid catalyst and performing hydrolysis, where the silicon compound contains at least a quadri-functional silane compound and a tri-functional silane compound among quadri-functional silane compounds, tri-functional silane compounds, and di-functional silane compounds, the density of the aerogel is 0.15 g/cm.sup.3 or less, for example the silicon compound is a mixture of a quadri-functional silane compound, a tri-functional silane compound, and a di-functional silane compound having portions satisfying 0<Qx<50, 50≤Tx<100, 0≤Dx<30, and Qx+Tx+Dx=100, where Qx, Tx, and Dx represent the mass percentages of the quadri-functional silane compound, the tri-functional silane compound, and the di-functional silane compound, respectively. This provides aerogel having excellent thermal insulating characteristics and a large area.

A production method for an aerogel includes a sol generation step by adding a silicon compound to an aqueous solution containing an acid catalyst and performing hydrolysis, where the silicon compound contains at least a quadri-functional silane compound and a tri-functional silane compound among quadri-functional silane compounds, tri-functional silane compounds, and di-functional silane compounds, the density of the aerogel is 0.15 g/cm.sup.3 or less, for example the silicon compound is a mixture of a quadri-functional silane compound, a tri-functional silane compound, and a di-functional silane compound having portions satisfying 0<Qx<50, 50≤Tx<100, 0≤Dx<30, and Qx+Tx+Dx=100, where Qx, Tx, and Dx represent the mass percentages of the quadri-functional silane compound, the tri-functional silane compound, and the di-functional silane compound, respectively. This provides aerogel having excellent thermal insulating characteristics and a large area.

Mesoporous silica is disclosed possessing a two-dimensional, hexagonal, through-hole structure with a space group p6mm, that is formed using one or more water-soluble oxidized disulfide oil (ODSO) compounds during the synthesis to impart distinct characteristics including an increased percentage of silanol groups.

A method for producing a silica sol containing a small amount of metal impurities and wherein colloidal silica having an elongated particle shape is dispersed in a solvent, by addition of a compound as an anion source and ammonia as an alkali source and heating of the resultant mixture at a predetermined temperature, includes the following steps: (a) preparing a raw material liquid by adding at least one compound as an anion source selected from the group of inorganic acids, organic acids, and ammonium salts of these acids, and ammonia to a silica sol as a raw material having SiO.sub.2 of 1% by mass to 30% by mass and a pH of 2 to 5 so the mass ratio of the compound to SiO.sub.2 is 0.5% to 1.9%; and (b) heating the raw material liquid prepared in step (a) at 80° C. to 200° C. for 0.5 hours to 20 hours.

The invention relates to a method of making hybrid organic-inorganic core-shell nano-particles, comprising the steps of a) providing colloidal organic particles comprising a synthetic polyampholyte as a template; b) adding at least one inorganic oxide precursor; and c) forming a shell layer from the precursor on the template to result in core-shell nano-particles. With this method it is possible to make colloidal organic template particles having an average particle size in the range of 10 to 300 nm; which size can be controlled by the comonomer composition of the polyampholyte, and/or by selecting dispersion conditions. The invention also relates to organic-inorganic or hollow-inorganic core-shell nano-particles obtained with this method, to compositions comprising such nano-particles, to different uses of said nano-particles and compositions, and to products comprising or made from said nano-particles and compositions, including anti-reflective coatings and composite materials.