Patents Assigned to AB CDM
  • Patent number: 6391156
    Abstract: A process of making paper or paper board comprising forming a cellulosic suspension, flocculating the suspension, draining the suspension on a screen to form a sheet and then drying the sheet, characterized in that the suspension is flocculated using a flocculation system comprising a clay and an anionic branched water soluble polymer that has been formed from water soluble ethylenically unsaturated anionic monomer or monomer blend and branching agent and wherein the polymer has (a) intrinsic viscosity above 1.5 dl/g and/or saline Brookfield viscosity of above about 2.0 mPa.s and (b) rheological oscillation value of tan delta at 0.005 Hz of above 0.7 and/or (c) deionised SLV viscosity number which is at least three times the salted SLV viscosity number of the corresponding unbranched polymer made in the absence of branching agent.
    Type: Grant
    Filed: November 2, 2000
    Date of Patent: May 21, 2002
    Assignees: AB CDM Vastra Frolunda, Ciba Specialty Chemicals Watertreatments Ltd.
    Inventors: Bo Hjalmarson, Hans Åsberg, Per-Ola Eriksson, Torbjörn Ljungqvist, Gary Peter Richardson, Gordon Cheng I Chen
  • Patent number: 6063240
    Abstract: Paper or paper board is made by adding cationic polymeric retention aid to a cellulosic supension, shearing the suspension to degrade the resultant flocs, aggregating the suspension by adding an aqueous composition of bentonite or other anionic bridging coagulant in the presence of anionic dye, pigment or optical brightening agent, and forming paper from the aggregated suspension.
    Type: Grant
    Filed: November 28, 1997
    Date of Patent: May 16, 2000
    Assignees: Allied Colloids Limited, AB CDM
    Inventors: Per-Ola Eriksson, Ingvar Eriksson, Bo Hjalmarson, John Graham Langley
  • Patent number: 5846433
    Abstract: A suspension is dosed with a coagulant and then with a flocculant and is dewatered to form a thickened sludge or cake and separated liquor, and control of the dewatering performance is improved by adding the flocculant at a predetermined dosage, monitoring the charge in the separated liquor (or monitoring other dewatering parameter of the separated liquor or suspension) and adding coagulant at a dosage selected in response to the monitored charge or other parameter value in order to maintain the value substantially at a preselected optimum value.
    Type: Grant
    Filed: April 16, 1997
    Date of Patent: December 8, 1998
    Assignees: Allied Colloids Limited, AB CDM
    Inventors: Jens Sorensen, John Rodney Field