PAPER AND CARDBOARD MANUFACTURE PROCESS Russian patent published in 2005 - IPC

FIELD: paper-and-pulp industry.

SUBSTANCE: process comprises preparation of paper pulp, flocculation of pulp, drainage of pulp on the screen to form sheet, and subsequent drying of sheet. Flocculation involves flocculation system including water-soluble anionic branched polymer and silicon-containing material. Polymer is prepared using water-soluble anionic ethylenically-unsaturated monomer or monomer mixture and ramification-forming agent. Polymer is characterized by intrinsic viscosity above 1.5 dl/g and/or Brookfield viscosity in salt solution above about 2.0 mPa·s, rheological oscillation delta tangent value at 0.005 Hz above 0.7, and/or reduced viscosity in deionized water at least thrice exceeding reduced viscosity in salt solution of corresponding nonbranched polymer obtained in absence of ramification-forming agent.

EFFECT: improved drainage, retention, and formation process.

14 cl, 1 dwg, 6 tbl, 6 ex