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US 8,709,208 B2Granted
Method to increase dewatering, sheet wet web strength and wet strength in papermaking
AssigneeNalco Company
InventorsYulin Zhao, Jun Li, Qing Long Rao, Weiguo Cheng
Life of this patent
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Abstract
The invention provides a method of improving dewatering efficiency, increasing sheet wet web strength, increasing sheet wet strength and enhancing filler retention in a papermaking process. The method improves the efficiency of dewatering aid by coating at least some of the filler particles with a material that prevents the filler materials form adhering to dewatering aids. The dewatering aid holds the paper fibers together tightly and is not wasted on the filler particles.
Claims14
A method of papermaking comprising filler, the method comprising the steps of:
- providing an aqueous dispersion of filler particles, at least one dewatering aid and cellulose fiber stock,
- adding a first flocculating agent to an aqueous dispersion of filler particles in an amount sufficient to mix uniformly in the dispersion without causing significant flocculation of the filler particles,
- adding a second flocculating agent to the dispersion after adding the first flocculating agent in an amount sufficient to initiate flocculation of the filler particles in the presence of the first flocculating agent, the second flocculating agent being of opposite charge to the first flocculant,
- combining the filler particles with the paper fiber stock,
- treating the combination with at least one dewatering aid selected from the group consisting of synthetic dewatering additives, and
- forming a paper mat from the combination,
- the paper fiber stock comprises a plurality of fibers and water, and
- the filler pre-flocculation enhances the performance of the dewatering aid in the paper mat.
5 more elements
Dependencies are inferred from the claim text.