Method for producing a sheet of paper comprising calcite
US7504000B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Feb 14, 2002 |
| Grant date | Mar 17, 2009 |
| Priority date | — |
| Expiry date | May 24, 2022 |
Classification
- Technology area (CPC D)Textiles; Paper
- CPC primaryD21H17/675
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
The invention relates to a method for producing a sheet of paper (6) comprising paper fibres and calcium carbonate mainly in the form of calcite crystals linked directly to the paper fibres. The inventive method is characterised in that it comprises the following steps:—(i) an aqueous composition comprising calcium bicarbonates (5) and/or hydrated and/or dissolved carbon dioxide (3) and (ii) an aqueous composition comprising calcium hydroxide (4) are mixed in an aqueous medium in such a way as to precipitate the calcium carbonate in the form of vaterite crystals;—paper fibres (2, 2′) are immediately added;—the vaterite crystals are left to transform into calcite crystals on contact with the fibres;—said mixture containing the calcite crystals which are fixed to the fibres is subsequently sent on the conveying wire of the papermaking machine (M) for drainage and so that the sheet of paper can be formed;—the sheet of paper (6) thus obtained is treated, if necessary, and dried.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.