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US 6,666,953 B1Granted
Treated filler or pigment containing natural carbonate
AssigneeOmya AG
InventorsPatrick A. C. Gane, Matthias Buri, Rene Vinzenz Blum, Beat Karth
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AssigneeOmya AG
InventorsPatrick A. C. Gane, Matthias Buri, Rene Vinzenz Blum, Beat Karth
Estimating the term…
The invention concerns a pigment, filler or mineral containing a natural calcium carbonate, treated with one of more providers of H3O+ ions and gaseous CO2, allowing a reduction in the weight of paper for a constant surface area without loss of physical properties when it is used as a pigment or coating filler for the said paper. In particular, the invention concerns a pigment, filler or mineral containing a natural calcium carbonate or dolomite or mixtures of talc and calcium carbonate, of kaolin and carbonate or carbonate alone or in combination with natural and/or synthetic fibers or similar, treated with one or more medium-strong or strong providers of H3O+ ions in the presence of gaseous CO2. Applications are particularly in the paper industry, obtaining in particular good sheet properties i.e. a reduction its weight for a given surface area.
An aqueous suspension comprising (1) one or more pigments, fillers or minerals, and optionally (2) a dispersant polymer to stabilise the rheology of the suspension, wherein,
A process for treating pigments, fillers or minerals in aqueous suspension, containing a natural carbonate, comprising treating said pigments, fillers or minerals with a combination of one or more medium-strong to strong H3O+ ion-providers and gaseous CO2, wherein said strong H3O+ ion-providers are selected from the group consisting of acids having a pKa value of less than or equal to zero at 22° C., and said medium-strong H3O+ ion-providers are selected from the group consisting of acids having a pKa value of between zero and 2.5 inclusive at 22° C., and wherein the pigments, fillers or minerals have a BET specific surface area, measured in accordance with the ISO 9277 Standard, of between 5 m2/g and 200 m2/g.
Dependencies are inferred from the claim text.