Method for producing a sheet of paper comprising calcite
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United States of America Patent
Stats
-
Mar 17, 2009
Grant Date -
Jun 24, 2004
app pub date -
Feb 14, 2002
filing date -
Feb 16, 2001
priority date (Note) -
Expired
status (Latency Note)
Importance
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.
First Claim
Other Claims data not available
