Process for producing silica particles suitable for use as filler for paper
US6264907A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 11, 1999 |
| Grant date | Jul 24, 2001 |
| Priority date | — |
| Expiry date | Mar 11, 2019 |
Classification
- Technology area (CPC D)Textiles; Paper
- CPC primaryD21H21/52
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
The present invention relates to a process for easily and efficiently producing silica particles having a narrow particle size distribution and a high porosity from inexpensive starting materials such as sodium silicate. The silica particles of the present invention can be obtained in the form of a slurry containing them by (1) forming a slurry by mixing first particles difficultly soluble in an alkali and soluble in an acid, with an aqueous alkali silicate solution to form a first slurry containing the first particles, (2) neutralizing the first slurry with a mineral acid to prepare a second slurry containing second particles wherein silica is deposited on the first particles, and (3) adding a mineral acid to the second slurry to dissolve the first particles from the second particles, to prepare a third slurry containing silica particles. When the silica particles of the present invention are used as a filler even in a small amount for paper making, the resultant papers have excellent brightness, opacity, opacity-after-printing, etc.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.