Method for fixing a mineral filler on cellulosic fibers and method for making a sheet of paper
AssigneeGeorgia-Pacific France
InventorsDidier Joisson, Christian Richard, Gilbert Schohn, Cyrille Schu
Life of this patent
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Abstract
The invention relates to a method for affixing a mineral filler onto an aqueous cellulose-fiber suspension. In this invention, the method uses as its reaction medium an aqueous cellulose-fiber suspension which is derived from papermaking and which includes at least hydrogen carbonates, carbonates or silicates of alkali and/or earth alkali metals, and the invention adds to the reaction medium a hydroxide of the filler mineral in order to precipitate the mineral filler's carbonates or silicates onto the fibers. In particular, the invention applies to papermaking.
Claims9
A method for affixing mineral fillers on cellulose fibers in an aqueous suspension comprising providing a reaction medium of an aqueous suspension of cellulose fibers, said suspension being derived from a papermaking procedure and containing hydrogen carbonates, carbonates or silicates of alkali and/or earth alkali metals, and adding a hydroxide of a mineral filler to said reaction medium to precipitate carbonates or silicates of the mineral filler onto the fibers, and wherein the aqueous suspension of cellulose fibers includes sodium hydrogen carbonates.
A method for affixing mineral fillers on cellulose fibers in an aqueous suspension comprising providing a reaction medium of an aqueous suspension of cellulose fibers, said suspension being derived from a papermaking procedure and containing hydrogen carbonates, carbonates or silicates of alkali and/or earth alkali metals, and adding a hydroxide of a mineral filler to said reaction medium to precipitate carbonates or silicates of the mineral filler onto the fibers, and wherein the hydroxide of the mineral filler is a calcium hydroxide added in as a concentrated milk or in soluble form.
A manufacturing process for sheets of paper comprising
- (a) providing a manufacturing composition based on water and on a bleached or unbleached chemical pulp of paper fibers, on a mechanical pulp, or on a thermomechanical pulp, or on a mixture thereof, said composition comprising at least alkali metal and/or earth alkali metal ions, and silicate or carbonate and hydrogen carbonate ions,
- (b) adding to said composition a hydroxide of a mineral filler to affix said mineral filler onto the paper fibers, and
- (c) forming a wet sheet of paper on a papermaking machine from the paper fibers which were precipitate-loaded in suspension and drying said sheet,
- wherein the manufacturing composition includes sodium and hydrogen carbonate ions in ionic equilibrium.
A manufacturing process for sheets of paper comprising
- (a) providing a manufacturing composition based on water and on a bleached or unbleached chemical pulp of paper fibers, on a mechanical pulp, or on a thermomechanical pulp, or on a mixture thereof, said composition comprising at least alkali metal and/or earth alkali metal ions, and silicate or carbonate and hydrogen carbonate ions,
- (b) adding to said composition a hydroxide of a mineral filler to affix said mineral filler onto the paper fibers,
- (c) forming a wet sheet of paper on a papermaking machine from the paper fibers which were precipitate-loaded in suspension and drying said sheet,
- (d) recovering drip waters of stage (c) and injecting into the drip waters a gas-containing carbon dioxide to neutralize and stabilize the pH of said drip waters, and
- (e) recycling the drip waters as processed in (d) into the manufacturing composition of (a),
- wherein the manufacturing composition includes sodium and hydrogen carbonate ions in ionic equilibrium.
Dependencies are inferred from the claim text.