Akzo Nobel N.v.

Eka Chemicals Ab

Eka Nobel Ab

Akzo Nobel Chemicals International B.v.

Akzo Nobel Pulp and Performance Chemicals Ab

Michael Persson

Marek T Tokarz

Maj-Lis Dahlgren

Erik Lindgren

Hans Erik Johansson-Vestin

Hans E Johansson

Rein Sikkar

Joakim Carlén

Sten Frölich

Freddie Hansson

Annika Viola Pal

Joakim Carlen

Carlos Cordoba

Barbro Magnusson

Lars Lindahl

Roman Kozlowski

Maria Norell

Bozena Stanislawa Tokarz

Patrik Simonson

Sten Fr&ouml;lich

Marek Tokarz

Hans Johansson

The invention relates to a sol containing silica-based particles having an axial ratio of at least about 10 and specific surface area of at least about 600 m2/g. The invention further relates to a sol containing silica-based particles having an axial ratio of at least about 10 and S-value up to about 25. The invention further relates to a sol containing silica-based particles having an axial ratio of at least about 10 and a specific surface area of at least about 400 m2/g, wherein the silica-based particles are surface-modified. The invention further relates to a sol containing silica-based particles having a viscosity of at least 50 cP and silica content of at least about 3% by weight, wherein the silica-based particles have a specific surface area of at least about 400 m2/g. The invention further relates to a process for producing the aqueous silica-based sol according to the invention, a sol containing silica-based particles obtainable by the process, use of the sol containing silica-based particles as a flocculating agent. The invention further relates to a process for producing paper in which the sol containing silica-based particles is used as a drainage and retention aid.

Silica-based sols

The present invention relates to a filler composition comprising a) a filler, b) a cationic inorganic compound, c) a cationic organic compound, and d) an anionic polysaccharide, wherein the filler is present in an amount of at least about 1% by weight, based on the total weight of the composition, the anionic polysaccharide is present in an amount of about 1 to about 100 kg/ton, based on the weight of filler, and wherein the composition is substantially free from fibers. The invention further relates to a filler composition comprising a), b), c) and d) as defined above wherein the filler is present in an amount of at least about 1% by weight, based on the total weight of the composition, the cationic inorganic and organic compounds are each present in an amount of from about 0 to about 30 kg/ton, based on the weight of filler, whereby the composition comprises at least one of the cationic inorganic and organic compounds, and the anionic polysaccharide has a degree of substitution of net anionic groups of up to about 0.65. The invention further relates to a method of preparing a filler composition comprising mixing a), b), c) and d) as defined above. The invention further relates to a filler composition obtainable by the method, use of a filler composition as an additive to an aqueous cellulosic suspension in a papermaking process, and a process of producing paper comprising adding the filler composition to an aqueous cellulosic suspension. The invention further relates to paper obtainable by the process and paper comprising the filler composition.

Filler composition

An aqueous sol containing silica-based particles which sol has a specific surface area of at least 115 m/g aqueous sol and a pH of at least 10.5, and an S-value within the range of from 10 to 45% and/or contains silica-based particles having a specific surface area of at least 550 and less than about 1200 m/g SiO, and wherein the sol is substantially free from aluminium.

The invention relates to an aqueous sol containing silica-based particles which sol has a specific surface area of at least 115 m/g aqueous sol and an S-value within the range of from 10 to 45% or contains silica-based particles having a specific surface area of at least 550 m/g and less than 1000 m/g SiO. The invention further relates to processes for the production of said aqueous sol and the use of the aqueous sol containing silica-based particles as a drainage and retention aid in the production of paper as well as a process for the production of paper from an aqueous suspension containing cellulosic fibres, and optional filler, in which silica-based particles and at least one charged organic polymer are added to the cellulosic suspension.

A process for the production of paper which includes the steps of providing an aqueous suspension containing cellulosic fibers, and optional fillers; adding to the suspension: (a) at least one charged organic polymer; and (b) an aqueous sol containing silica-based particles; wherein the sol has: (i) an S-value within the range of from 10 to 45%; (ii) a viscosity within the range of from 5 to 40 cP; and (iii) a molar ratio of SiOto MO, where M is alkali metal or ammonium, within the range of from 10:1 to 40:1; and (III) forming and draining the suspension on a wire. The invention is further directed to processes for making paper wherein the added sol has: (i) an S-value within the range of from 10 to 45%; (ii) a viscosity within the range of from 5 to 40 cP; and (iii) a silica content of at least 10% by weight, or wherein the added sol has: (i) an S-value within the range of from 10 to 45%; (ii) a viscosity within the range of from 7 to 25 cP; (iii) a silica content of at least 10% by weight; (iv) a molar ratio of SiOto MO, where M is alkali metal or ammonium, within the range of from 10:1 to 40:1; and (v) a pH of at least 10.6. The invention is further directed to a process for making paper wherein the added sol is modified by an aluminum-containing compound, a boron-containing compound or a mixture thereof and has: (i) an S-value within the range of from 10 to 45%; (ii) a viscosity within the range of from 5 to 40 cP; (iii) a silica content of at least 10% by weight; and (iv) a molar ratio of SiOto MO, where M being alkali metal or ammonium, within the range of from 10:1 to 40:1.

Production of paper using slica-based-sols

The present invention generally relates to polysilicate microgels. More specifically, the invention relates to a process for preparing aqueous polysilicate microgels which comprises mixing an aqueous solution of alkali metal silicate with an aqueous phase of silica-based material having a pH of 11 or less, to polysilicate microgels per se and to the use thereof as flocculating agents in paper making and water purification. The invention further relates to a process for the production of paper from a suspension of cellulosic fibers, and optional filler, which comprises adding to the suspension at least one cationic or amphoteric organic polymer and a polysilicate microgel, forming and draining the suspension on a wire.

Polysilicate microgels

A process for sizing paper comprising adding to an aqueous suspension containing cellulosic fibers, and optional fillers, a sizing dispersion comprising a polymer having an aromatic group, and a sizing promoter comprising a polymer having an aromatic group, wherein the sizing dispersion and the sizing promoter are added separately to the aqueous suspension.

Process for sizing paper

An aqueous sol containing silica-based particles which has an S-value within the range of from 10 to 45%, a viscosity within the range of from 5 to 40 cP, and a molar ratio of SiOto MO, where M is alkali metal or ammonium, within the range of from 10:1 to 40:1, or a silica content of at least 10% by weight. The invention further relates to a process for the production of silica-based particles comprising the steps of: (a) acidifying an aqueous silicate solution to a pH of from 1 to 4 to form an acid sol; (b) alkalising the acid sol at an SiOcontent within the range of from 4.5 to 8% by weight to; (c) allowing particle growth of the alkalised sol for at least 10 minutes, or heat-treating the alkalised sol at a temperature of a least 30&#xb0; C.; and then (d) alkalising the obtained sol to a pH of at least 10.0. The invention further relates to silica-based particles obtainable by the process, the use of the silica-based particles as drainage and retention aids in the production of paper as well as a process for the production of paper from an aqueous suspension containing cellulosic fibers, and optional filler, in which silica-based particles and at least one charged organic polymer are added to the cellulosic suspension.

A process for sizing paper comprising adding to an aqueous suspension containing cellulosic fibers, and optional fillers, an anionic or cationic sizing dispersion, and a sizing promoter comprising a cationic organic polymer having an aromatic group; and an anionic polymer having an aromatic group selected from step-growth polymers, polysaccharides and naturally occurring aromatic polymers, wherein the sizing dispersion and sizing promoter are added separately to the aqueous suspension.

A process for sizing paper comprising adding to an aqueous suspension containing cellulosic fibres, and optional fillers, a sizing dispersion comprising a polymer having an aromatic group, and a sizing promoter comprising a polymer having an aromatic group, wherein the sizing dispersion and the sizing promoter are added separately to the aqueous suspension.

The present invention relates to polysilicate microgels, their preparation and use in paper making and water purification, the polysilicate microgels being obtainable by a process which comprises bringing into contact (i) particles of a salt AB with an aqueous silicate or polysilicate solution, (ii) an ion A with an ion B in the presence of an aqueous silicate or polysilicate solution, whereby the salt AB is precipitating in the aqueous phase, or (iii) an ion A with an ion B in the presence of an aqueous silicate or polysilicate solution, whereby the ions A and B represent ions of a precipitable salt AB having a pK value of at least 4, measured at 20&deg; C. in water. The invention further relates to aqueous silicate or polysilicate solutions, their preparation and use as precursors for polysilicate microgels. The aqueous silicate or polysilicate solutions contain an ion A which is calcium or magnesium, wherein the molar ratio of SiO :A is less than 2000:1 and higher than 1:1, or an ion B which is carbonate, sulfate or phosphate, wherein the molar ratio of SiO :B is less than 2000:1 and higher than 1:1.

Polysilicate microgels and silica-based materials

A process for the production of paper in which cellulosic fibers are treated with microparticles comprising shell-formed carbon allotrope particles, paper obtainable from this process, and a drainage and/or retention agent comprising at least partially hydrophilic, anionic microparticles comprising shell-formed carbon allotrope particles.

Process for the production of paper

The invention concerns a method of protecting a surface of a carbonatic material from corrosion, the method comprising treatment of the material surface with an acidic cationic silica sol, the pH of the sol preferably being from about 4 to about 7. The invention also concerns a new silica sol useful for performing the method and a method of preparing the new silica sol. Further, the invention concerns carbonatic material comprising a surface layer of silica, the surface of the silica particles comprising a polyvalent metal oxide/hydroxide.

Method of protecting a surface

The invention relates to a process for the production of paper from a suspension of cellulose containing fibers, and optional fillers, comprising adding to the suspension a low molecular weight cationic organic polymer, a high molecular weight cationic or amphoteric polymer and anionic inorganic particles, forming and draining the suspension on a wire, wherein the low molecular weight polymer has a molecular weight below 700,000 and the high molecular weight polymer has a molecular weight above 1,000,000, said polymers being simultaneously added to the suspension. The invention further relates to a polymer mixture in the form of an aqueous dispersion comprising at least one high molecular weight cationic or amphoteric acrylamide-based polymer having a molecular weight above 1,000,000, at least one low molecular weight cationic organic polymer having a molecular weight below 700,000 and at least one water-soluble inorganic salt, the weight ratio of said high molecular weight polymer to said low molecular weight polymer being within the range of from 9:1 to 1:2.

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Västra Frölunda, Sweden

Michael Persson