Method of increasing filler content in papermaking
AssigneeNalco Company
InventorsWeiguo Cheng, Ross T. Gray
Life of this patent
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Abstract
The invention provides a method of producing paper with a higher proportion of mineral filler particles than is otherwise be possible without the expected loss in paper strength by preflocculating the filler particles. The method allows for the use of the greater amount of filler particles by coating at least some of the filler particles with a material that prevents the filler materials form adhering to a strength additive. The strength additive holds the paper fibers together tightly and is not wasted on the filler particles.
Claims17
A method of papermaking having an increased filler content, the method comprising the steps of:
- adding a first flocculating agent to an aqueous dispersion 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 strength additive selected from the group consisting of synthetic strength additives, and
- forming a paper mat from the combination,
- the paper fiber stock comprises a plurality of fibers and water, and
- the initiated flocculation enhances the performance of the strength additive in the paper mat, wherein the strength additive is not starch.
Dependencies are inferred from the claim text.