Abstract:
The present invention relates to hydronium stabilized silicic acid nanoparticles, to the formulation obtained from the said diluted suspension, to the powder obtained from the said dehydrated suspension and to the preparation or dosage form obtained from the said suspension, formulation or powder, to their preparation and their use in all kinds of applications in the domains of food, medicine, pharmaceutics, cosmetics. The present invention provides a stable suspension of colloidal silicic acid nanoparticles having a pH lower than 0.9, a molar silicon concentration between 0.035 and 0.65, a free water concentration of at least 30% (w/v) and a ratio between hydronium ion and Si molar concentrations higher than 2 and preferably inferior to 4. The present invention further provides a method for preparing a stable suspension of colloidal silicic acid nanoparticles, which comprises the steps of providing an aqueous inorganic or organic silicon solution and quick mixing said aqueous inorganic or organic silicon solution with water containing a strong acidic compound at a temperature inferior at 300°C, preferably comprised between 1 and 25°C, to form a suspension of colloidal silicic acid nanoparticles having a pH lower than 0.9, stabilized by hydronium ions, the ratio between hydronium ions and Si molar concentrations being higher than 2 and preferably inferior to 4, for a molar silicon concentration between 0.035 and 0.65 and a free water concentration of at least 30% (w/v).
Abstract:
The present invention relates to hydronium stabilized silicic acid nanoparticles, to the formulation obtained from the said diluted suspension, to the powder obtained from the said dehydrated suspension and to the preparation or dosage form obtained from the said suspension, formulation or powder, to their preparation and their use in all kinds of applications in the domains of food, medicine, pharmaceutics, cosmetics. The present invention provides a stable suspension of colloidal silicic acid nanoparticles having a pH lower than 0.9, a molar silicon concentration between 0.035 and 0.65, a free water concentration of at least 30% (w/v) and a ratio between hydronium ion and Si molar concentrations higher than 2 and preferably inferior to 4. The present invention further provides a method for preparing a stable suspension of colloidal silicic acid nanoparticles, which comprises the steps of providing an aqueous inorganic or organic silicon solution and quick mixing said aqueous inorganic or organic silicon solution with water containing a strong acidic compound at a temperature inferior at 300°C, preferably comprised between 1 and 25°C, to form a suspension of colloidal silicic acid nanoparticles having a pH lower than 0.9, stabilized by hydronium ions, the ratio between hydronium ions and Si molar concentrations being higher than 2 and preferably inferior to 4, for a molar silicon concentration between 0.035 and 0.65 and a free water concentration of at least 30% (w/v).
Abstract:
A method of manufacturing a colloidal silica dispersion, by dissolving a fumed silica in an aqueous solvent having an alkali metal hydroxide to produce an alkaline silicate solution; removing the alkali metal via ion exchange to produce a silicic acid solution; adjusting the temperature, concentration and pH of the silicic acid solution to values sufficient to initiate nucleation and particle growth at elevated temperatures; and cooling the silicic acid solution at a rate sufficient to produce the colloidal silica dispersion. The colloidal silica particles in the colloidal silica dispersion have a mean particle size about 2 nm to about 100 nm. Also provided is a method of chemical mechanical polishing a surface of a substrate by contacting the substrate and a composition having a plurality of colloidal silica particles according to the present invention and a medium for suspending the particles. The contacting is carried out at a temperature and for a period of time sufficient to planarize the substrate.
Abstract:
The invention relates to a process for producing an aqueous silica-based sol which comprises: (a) providing a cationic ion exchange resin having at least part of its ion exchange capacity in hydrogen form; (b) bringing said ion exchange resin in contact with an aqueous alkali metal silicate to form an aqueous slurry; (c) stirring said aqueous slurry until the pH of the aqueous phase is in the range of from 5.0 to 8.0; (d) adjusting the pH of said aqueous phase to above 9.0; and (e) separating said ion exchange resin from the aqueous phase after step (c) or after step (d). The invention also relates to an aqueous silica-based sol obtainable by the processes as well as a process for producing paper which comprises (i) providing an aqueous suspension comprising cellulosic fibres; (j) adding to the suspension one or more drainage and retention aids comprising an aqueous silica-based sol according to the invention; and (k) dewatering the obtained suspension to provide a sheet or web of paper.
Abstract:
Provided is a method for the preparation of high solids, low sodium content polysilicic acid (PSA). The method includes the steps of acidifying a waterglass solution such that the pH of the solution falls to 4 or less in a time period of less than about 20 seconds; and contacting the reduced pH waterglass solution with an acid exchange resin. In a preferred embodiment, the PSA is prepared in a recirculating loop.
Abstract:
The present invention relates to hydronium stabilized silicic acid nanoparticles able to dissolve in aqueous environments, to their preparation and use. The present invention provides a stable suspension of colloidal silicic acid nanoparticles having a pH lower than 0.9, a molar silicon concentration between 0.035 and 0.65, a free water concentration of at least 30% (w/v) and a ratio between hydronium ion and Si molar concentrations higher than 2 and preferably inferior to 4. The present invention further provides a method for preparing a stable suspension of colloidal silicic acid nanoparticles, which comprises the steps of providing an aqueous inorganic or organic silicon solution and quick mixing said aqueous inorganic or organic silicon solution with water containing a strong acidic compound at a temperature inferior at 30°C, preferably comprised between 1 and 25°C, to form a suspension of colloidal silicic acid nanoparticles having a pH lower than 0.9, stabilized by hydronium ions, the ratio between hydronium ions and Si molar concentrations being higher than 2 and preferably inferior to 4, for a molar silicon concentration between 0.035 and 0.65 and a free water concentration of at least 30% (w/v).
Abstract:
Die vorliegende Erfindung betrifft ein Verfahren zur Herstellung von Metall-oder Halb- metalloxid-Nanopartikeln der allgemeinen Formel (I), worin M 1 , a und b die folgenden Bedeutungen haben: M 1 Metall oder Halbmetall ausgewählt aus den Gruppen 1 bis 15 des Periodensystems der Elemente (IUPAC) der Lanthanoide, Actinoide und Mischungen davon, a 1 -4 und b 1 -4, wobei a und b in Abhängigkeit von der Oxidationsstufe von M 1 so gewählt sind, dass die Verbindung der allgemeinen Formel (I) neutral geladen ist, umfassend die folgenden Schritte: (A) Bereitstellen einer Lösung oder Dispersion wenigstens einer Verbindung der allgemeinen Formel (II), worin M 1 die oben genannte Bedeutung hat, und M 2 , x, y, z und n die folgenden Bedeutungen haben: M 2 Alkali-, ErdalkalimetalloderMischungen davon, x 0,5 -6,30 y 0,5 -6, z 0,5 -4 und n 0 -12 wobei x, y und z in Abhängigkeit von den Oxidationsstufen von M 1 und M 2 so gewählt sind, dass die wenigstens eine Verbindung der allgemeinen Formel (II) neutral geladen ist, in wenigstens einem organischen Lösungs-oder Dispersionsmittel als Reaktionsmischung, (B) Umsetzen der in der Reaktionsmischung aus Schritt (A) befindlichen wenigstens einen Verbindung der allgemeinen Formel (II) mit wenigstens einem sauren Ionentauscher durch Zugabe deswenigstens einen sauren Ionentauschers zu der Reaktionsmischung, um die Metall-oder Halbmetalloxid-Nanopartikel der allgemeinen Formel (I) zu erhalten und (C) Abtrennen des wenigstens einen sauren Ionentauschers von der Reaktionsmischung.
Abstract translation:本发明涉及一种用于生产通式(I)的金属或半金属氧化物纳米颗粒,其中,M1,a和b具有以下含义:M 1金属或从组1中选择至15的元素周期表的类金属 镧系元素,锕系元素的(IUPAC),以及它们的混合物,a是1-4和b 1-4,其中a和b是根据使得通式(I)的化合物是电中性的M1的氧化态选择,包括 (a)提供溶液或通式(II)中的至少一种化合物的分散体,其中M1具有以上给出的含义,和M2,X,Y,Z和n具有以下含义:M2碱,ErdalkalimetalloderMischungen的步骤 其中,x Y 0.5 -6.30 0.5 0.5 -6 -4ž和-12 N 0其中,x,y和z根据M1和M2的氧化态选择,使得至少 通式(II)诺伊特拉的化合物 升在位于(II)与通过加入至少一种酸性离子交换剂,所述通式中的至少一种化合物的至少一种有机溶剂或分散剂作为反应混合物,(B)在步骤(A)的反应混合物反应加载至少一种酸性离子交换剂,以 以获得和(C)从反应混合物中分离出至少一种酸性离子交换剂。将反应混合物的通式(I)的金属或半金属氧化物纳米颗粒,
Abstract:
The invention relates to a sol containing silica-based particles having an axial ratio of at least about 10 and specific surface area of at least about 600 m2/g. The invention further relates to a sol containing silica-based particles having an axial ratio of at least about 10 and S-value up to about 25. The invention further relates to a sol containing silica-based particles having an axial ratio of at least about 10 and a specific surface area of at least about 400 m2/g, wherein the silica-based particles are surface-modified. The invention further relates to a sol containing silica-based particles having a viscosity of at least 50 cP and silica content of at least about 3 % by weight, wherein the silica-based particles have a specific surface area of at least about 400 m2/g. The invention further relates to a process for producing the aqueous silica-based sol according to the invention, a sol containing silica-based particles obtainable by the process, use of the sol containing silica- based particles as a flocculating agent. The invention further relates to a process for producing paper in which the sol containing silica-based particles is used as a drainage and retention aid..