Silica-calcium carbonate composite particles
US7060127B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 2, 2001 |
| Grant date | Jun 13, 2006 |
| Priority date | — |
| Expiry date | Sep 9, 2021 |
Classification
- Technology area (CPC D)Textiles; Paper
- CPC primaryD21H17/675
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
Silica-calcium carbonate composition particles having the characteristics of both synthetic silica and calcium carbonate are described along with paper having the particles internally filled therein and a method for making the particles.In the carbonation reaction, which typically involves a step of forming calcium carbonate, while agitating a calcium hydroxide slurry, a mixed gas of carbon dioxide and air is introduced thereinto and synthetic silica, such as colloidal silica or the like, is added before the carbonation rate arrives at 95% but after commencement of the carbonation reaction, followed by further introduction of the mixed gas to continue the carbonation reaction and completion of the carbonation reaction at the time when the pH of the slurry reaches 7, thereby providing the composite particles.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.