PAPER AND PAPERBOARD PRODUCTION PROCESS AND CORRESPONDING NOVEL RETENTION AND DRAINAGE AIDS, AND PAPERS AND PAPERBOARDS THUS OBTAINED
First Claim
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1. Process for manufacturing a sheet of paper or paperboard having improved retention and drainage properties comprising the step of:
- utilizing a dual system of (a) an acrylic polymer as a primary retention agent and (b) bentonite as a secondary retention agent, the introductions of which are separated by a step for shearing a suspension or fibrous mass or paper pulp,wherein said acrylic polymer is a branched, cationic, acrylic (co)polymer prepared in the form of a reverse phase water-in-oil emulsion, used either in emulsion reversed in water, or in a solution of the powder obtained by drying the emulsion, andwherein the branched, cationic, acrylic (co)polymer prepared in the form of a reverse phase water-in-oil emulsion has a UL viscosity that is greater than 3 cps.
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Abstract
The invention concerns an improved method for making paper, which uses a branched polymer prepared in invert emulsion as the main retention agent, and bentonite as a secondary retention agent (dual type system). The two additions are separated by a step for shearing the fibrous suspension (or mass). The invention results in highly improved retention and also highly improved dewatering. Moreover, it enables the bentonite content in white water to be reduced.
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Citations
23 Claims
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1. Process for manufacturing a sheet of paper or paperboard having improved retention and drainage properties comprising the step of:
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utilizing a dual system of (a) an acrylic polymer as a primary retention agent and (b) bentonite as a secondary retention agent, the introductions of which are separated by a step for shearing a suspension or fibrous mass or paper pulp, wherein said acrylic polymer is a branched, cationic, acrylic (co)polymer prepared in the form of a reverse phase water-in-oil emulsion, used either in emulsion reversed in water, or in a solution of the powder obtained by drying the emulsion, and wherein the branched, cationic, acrylic (co)polymer prepared in the form of a reverse phase water-in-oil emulsion has a UL viscosity that is greater than 3 cps. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 15, 17, 18, 19, 20, 21)
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12. Novel retention agent for the manufacture of a sheet of paper or paperboard characterized in that it comprises a) a branched polyacrylamide or optionally a branched acrylic (co)polymer which is a cationic copolymer of acrylamide and an unsaturated cationic ethylenic monomer, selected from the group consisting of dimethylaminoethyl acrylate (ADAME) and dimethylaminoethyl methacrylate (MADAME), that is quaternized or salified by a compound selected from the group consisting of different acids and quaternizing agents, benzyl chloride, methyl chloride, alkyl or aryl chlorides, dimethyl sulfate, diallyldimethylammonium chloride (DADMAC), acrylamidopropyltrimethylammonium chloride (APTAC), and methacrylamidopropyltrimethylammonium chloride (MAPTAC) in reverse phase emulsion, either in reverse phase emulsion dissolved or reversed in water, or in a solution of the powder obtained by drying or spray-drying the reverse phase emulsion;
- in combination with bentonite, and in combination with a branching agent.
- View Dependent Claims (13, 14, 22, 23)
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16. A process for manufacturing a sheet of paper or paperboard having improved retention and drainage properties, comprising the steps of:
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introducing an acrylic polymer as a primary retention agent to a suspension or fibrous mass or paper pulp wherein said acrylic polymer is a branched, cationic, acrylic(co)polymer in the form of a reverse phase water-in-oil emulsion used either in emulsion reversed in water, or in a solution of powder obtained by drying the emulsion; shearing the suspension or fibrous mass paper pulp; and introducing bentonite as a secondary retention agent.
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Specification