Clay compositions and their use in paper making
AssigneeCiba Specialty Chemicals Water Treatments Ltd.
InventorsAdrian Swinburn Allen, John Oliver Stockwell, Ian James Black
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Abstract
Paper making processes, including microparticulate processes, which utilise bentonite are provided with bentonite in the form of a concentrate, or a dilute dispersion made by diluting the concentrate, wherein the concentrate is a dispersion of 15 to 40% by weight bentonite in water containing citrate and has a viscosity below 5000 cps and is a stable fluid. The concentrates are novel. They are preferably made by mixing alkaline earth bentonite with water and sodium citrate.
Claims19
A process of making paper comprising forming a cellulosic suspension, mixing an activated bentonite dispersion into the cellulosic suspension, draining and cellulosic suspension to form a wet sheet and drying the sheet, wherein the activated bentonite dispersion which is added to the cellulosic suspension is a stable, fluid, bentonite concentrate or a dilute bentonite dispersion made by diluting the concentrate with water, and the concentrate is a dispersion of 15 to 40% by weight of bentonite in water containing citrate in a fluid stabilising and activating amount which is such that the concentrate has a viscosity (Brookfield, 20 rpm, spindle 4) of below 2000 cps.
A process according to claim in which the amount of citrate, measured as sodium citrate, is at least 6% by weight based on the weight of the concentrate.
A concentrate which is a stable, fluid, bentonite dispersion of 15 to 40% by weight bentonite in water containing citrate in a fluid stabilising and activating amount which is such that the concentrate has a viscosity (Brookfield, 20 rpm, spindle 4) of below 2000 cps.
A method of making a concentrate that is a stable, fluid, bentonite dispersion of 15 to 40% by weight bentonite in water containing citrate in a fluid stabilizing and activating amount which is such that the concentrate has a viscosity (Brookfield, 20 rpm, spindle 4) of below 2000 cps comprising mixing more than 15% by weight raw quarried alkaline earth bentonite with water and alkali metal or ammonium citrate, filtering the slurry and thereby providing the concentrate.
Dependencies are inferred from the claim text.