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US 6,475,341 B1Granted
Process for making paper
AssigneeCiba Specialty Chemicals Water Treatments Ltd.
InventorsHoward Johnston, Lesley Collett
Life of this patent
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Abstract
Paper is made by mixing anionic starch, carboxyl methyl cellulose or other polymeric binder into a cellulosic thin stock together with a cationic inorganic or polymeric coagulant and then flocculating the suspension by means of an anionic swelling clay or other anionic retention aid.
Claims9
A process for making paper comprising
- providing a thin stock suspension of cellulosic fibres,
- mixing into the suspension
- (a) a water soluble anionic or non-ionic polymeric binder and
- (b) a water soluble cationic material selected from water soluble organic polymeric coagulants having intrinsic viscosity below 3 dl/g and a charge density of above 3 meq/g, and inorganic coagulants,
- then flocculating the suspension by mixing into the suspension an anionic retention aid, draining the flocculated suspension to form a wet sheet, and drying the wet sheet.
2 more elements
Dependencies are inferred from the claim text.