| abstract |
Paper is made by forming a thick stock cellulosicnsuspension, flocculating the thick stock by adding anrelatively high molecular weight and relatively lowncationic charge density polymer, diluting the flocculatednthick stock to form a thin stock and then draining the thinnstock to form a sheet. Usually coagulant is added to thenthin stock before drainage and best results are achieved bynadding coagulant followed by anionic colloidal materialnsuch as bentonite. The process can be operated to givengood retention and good formation and, if the thick stocknis dirty, to minimise pitch problems. |