Polysilicate microgels and silica-based materials
US6673208B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 1, 2002 |
| Grant date | Jan 6, 2004 |
| Priority date | — |
| Expiry date | Jul 1, 2022 |
Classification
- Technology area (CPC D)Textiles; Paper
- CPC primaryD21H17/29
- WIPO fieldEnvironmental technology
- WIPO sectorChemistry
Abstract
The present invention relates to polysilicate microgels, their preparation and use in paper making and water purification, the polysilicate microgels being obtainable by a process which comprises bringing into contact (i) particles of a salt AB with an aqueous silicate or polysilicate solution, (ii) an ion A with an ion B in the presence of an aqueous silicate or polysilicate solution, whereby the salt AB is precipitating in the aqueous phase, or (iii) an ion A with an ion B in the presence of an aqueous silicate or polysilicate solution, whereby the ions A and B represent ions of a precipitable salt AB having a pKS value of at least 4, measured at 20° C. in water. The invention further relates to aqueous silicate or polysilicate solutions, their preparation and use as precursors for polysilicate microgels. The aqueous silicate or polysilicate solutions contain an ion A which is calcium or magnesium, wherein the molar ratio of SiO2:A is less than 2000:1 and higher than 1:1, or an ion B which is carbonate, sulfate or phosphate, wherein the molar ratio of SiO2:B is less than 2000:1 and higher than 1:1.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.