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US 7,608,644 B2Granted
Aqueous silica-containing composition
AssigneeAkzo Nobel N.V.
InventorsJohan Nyander, Hans Johansson-Vestin, Jan Nordin, Annika Viola Pal
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AssigneeAkzo Nobel N.V.
InventorsJohan Nyander, Hans Johansson-Vestin, Jan Nordin, Annika Viola Pal
Estimating the term…
The present invention refers to a process for the production of paper from a suspension containing cellulosic fibers, and optionally fillers, comprising adding to the suspension at least one cationic organic polymer and an aqueous silica-containing composition comprising an anionic naphthalene sulphonate formaldehyde condensate and anionic silica-based particles, the composition having a weight ratio of naphthalene sulphonate formaldehyde condensate to silica-based particles within the range of from 0.2:1 to 99:1, and containing naphthalene sulphonate formaldehyde condensate and silica-based particles in an amount of at least 0.01% by weight, based on the total weight of the aqueous silica-containing composition, and with the proviso that the composition contains substantially no cellulose-reactive sizing agent. The invention also encompasses an aqueous silica-containing composition and a method for preparation of an aqueous silica-containing compound.
An aqueous silica-containing composition comprising an anionic naphthalene sulphonate formaldehyde condensate and aggregated or microgel formed anionic silica-based particles, wherein the composition has a weight ratio of naphthalene sulphonate formaldehyde condensate to total amount of silica-based particles within the range of from 0.2:1 to 99:1, and wherein the amount of naphthalene sulphonate formaldehyde condensate and total amount of silica-based particles is at least 0.01% by weight, based on the total weight of the aqueous silica-containing composition, and with the provisos that the composition contains substantially no cellulose-reactive sizing agent and the composition is not a cellulosic papermaking stock, wherein the anionic naphthalene sulphonate formaldehyde condensate has a conductivity of less than 15 mS/cm measured at an anionic naphthalene sulphonate formaldehyde condensate content of 10% by weight.
A method for the preparation of an aqueous silica-containing composition which comprises mixing an aqueous anionic naphthalene sulphonate formaldehyde condensate solution having a conductivity less than 15 mS/cm with an aqueous alkali stabilised sol containing silica-based particles wherein the prepared aqueous silica-containing composition contains naphthalene sulphonate formaldehyde condensate and total amount of silica-based particles in an amount of at least 0.01% by, weight, wherein the conductivity is measured at an anionic naphthalene sulphonate formaldehyde condensate content of 10% by weight.
An aqueous silica-containing composition comprising an anionic naphthalene sulphonate formaldehyde condensate and aggregated or microgel formed anionic silica-based particles, wherein the composition has a weight ratio of naphthalene sulphonate formaldehyde condensate to total amount of silica-based particles within the range of from 0.2:1 to 99:1, and wherein the amount of naphthalene sulphonate formaldehyde condensate and total amount of silica-based particles is at least 0.5 % by weight, based on the total weight of the aqueous silica-containing composition, and with the proviso that the composition contains substantially no cellulose-reactive sizing agent, wherein the anionic naphthalene sulphonate formaldehyde condensate has a conductivity of less than 15 mS/cm measured at an anionic naphthalene sulphonate formaldehyde condensate content of 10% by weight.
Dependencies are inferred from the claim text.