Aqueous composition
View Patent ↗The present invention relates to an aqueous composition comprising anionic organic polymeric particles and colloidal anionic silica-based particles. The anionic organic polymeric particles are obtainable by polymerizing one or more ethylenically unsaturated monomers together with one or more polyfunctional branching agents and/or polyfunctional crosslinking agents. The anionic organic polymeric particles and the colloidal anionic silica-based particles in the aqueous composition are present in an amount of at least 0.01% by weight based on the total weight of the aqueous composition. The present invention further relates to a method for the preparation of the aqueous composition, uses of the aqueous composition and a process for the production or paper, in which the aqueous composition is added to a cellulosic suspension.
1. A process for production of paper from an aqueous suspension containing cellulosic fibres, and optionally fillers, which process comprises adding to the fibre suspension a cationic polymer and an aqueous composition comprising anionic organic polymeric particles and colloidal anionic silica-based particles having a specific surface area within the range from 300 to 1000 m 2 /g, the anionic organic polymeric particles being obtained by polymerising one or more ethylenically unsaturated monomers together with one or more polyfunctional branching agents and/or polyfunctional crosslinking agents, the anionic organic polymeric particles and the colloidal anionic silica-based particles being present in the aqueous composition in an amount of at least 0.01% by weight based on the total weight of the aqueous composition, the colloidal anionic silica-based particles being silica, aluminium-modified silica or amine-modified silica and being contained in a sol having an S-value within the range from 5 to 60% before mixing with the anionic organic polymeric particles.
2. The process according to claim 1 , wherein the weight ratio of the colloidal anionic silica-based particles to the anionic organic polymeric particles in the aqueous composition ranges from 20:1 to 1:50.
3. The process according to claim 1 , wherein the weight ratio of the colloidal anionic silica-based particles to the anionic organic polymeric particles in the aqueous composition ranges from 5:1 to 1:20.
4. The process according to claim 1 , wherein the colloidal anionic silica-based particles are being contained in a sol having an S-value within the range from 12 to 45%.
5. The process according to claim 1 , wherein the colloidal anionic silica-based particles are aluminium modified silica.
6. The process according to claim 1 , wherein the colloidal anionic silica-based particles are amine modified silica.
7. The process according to claim 1 , wherein the colloidal anionic silica-based particles have a particle size in the range of from 1 to 10 nm.
8. The process according to claim 1 , wherein the colloidal anionic silica-based particles are silica.
9. The process according to claim 1 , wherein the colloidal anionic silica-based particles have a specific surface area within the range of from 500 to 950 m 2 /g.
10. The process according to claim 1 , wherein the polyfunctional branching agent and/or polyfunctional crosslinking agent has at least two ethylenically unsaturated bonds.
11. The process according to claim 1 , wherein the anionic organic polymeric particles comprise one or more monomers selected from (meth)acrylic acids, alkyl (meth)acrylic acids, sulfoalkyl (meth)acrylic acids, unsaturated dicarboxylic acids, sulfonated styrenes, sulfoalkyl (meth)acrylamides, acrylamides, N-alkyl acrylamides, N,N-dialkyl-acrylamides, methacrylamides, vinylacetate, acrylo-nitrile, N-vinyl methylacetamide and N-vinyl pyrrolidone, and salts of said acids.
12. The process according to claim 1 , wherein the polyfunctional branching and/or the polyfunctional crosslinking agent has at least two ethylenically unsaturated bonds, an ethylenically unsaturated bond and a reactive group, or two reactive groups.
13. The process according to claim 1 , wherein an aluminium containing compound is added to the suspension before the cationic organic polymer.
14. The process according to claim 1 , wherein the dosage, counted as dry substances based on dry pulp and optional filler, of the aqueous composition comprising anionic organic polymeric particles and colloidal anionic silica-based particles is 0.01-10 kg/t.
15. The process according to claim 1 , wherein the anionic organic polymeric particles and the colloidal anionic silica-based particles are present in the aqueous composition in an amount of at least 0.05% by weight, based on the total weight of the aqueous composition.
16. The process according to claim 15 , wherein the anionic organic polymeric particles and the colloidal anionic silica-based particles are present in the aqueous composition in an amount of at least 0.1% by weight, based on the total weight of the aqueous composition.
17. The process according to claim 16 , wherein the anionic organic polymeric particles and the colloidal anionic silica-based particles are present in the aqueous composition within a range of from 1 to 45% by weight, based on the total weight of the aqueous composition.
18. The process according to claim 1 , wherein the cationic polymer is added before the addition of the aqueous composition.
19. The process according to claim 1 , wherein the cationic polymer is added before a shear stage and the aqueous composition is added after that shear stage.
20. A process for production of paper from an aqueous suspension containing cellulosic fibres, and optionally fillers, which process comprises adding to the fibre suspension a cationic polymer being a starch and/or an acrylamide-based polymer and an aqueous composition comprising anionic organic polymeric particles and colloidal anionic silica-based particles having a specific surface area within the range from 300 to 1000 m 2 /g, the anionic organic polymeric particles being obtained by polymerising one or more ethylenically unsaturated monomers together with one or more polyfunctional branching agents and/or polyfunctional crosslinking agents, the anionic organic polymeric particles and the colloidal anionic silica-based particles being present in the aqueous composition in an amount of at least 0.01% by weight based on the total weight of the aqueous composition, the colloidal anionic silica-based particles being silica, aluminium-modified silica or amine-modified silica and being contained in a sol having an S-value within the range from 5 to 60% before mixing with the anionic organic polymeric particles.
21. The process according to claim 20 , wherein the cationic polymer is an anionic acrylamide-based polymer.
22. The process according to claim 20 , wherein the anionic organic polymeric particles and the colloidal anionic silica-based particles are present in the aqueous composition in an amount of at least 0.05% by weight, based on the total weight of the aqueous composition.
23. The process according to claim 22 , wherein the anionic organic polymeric particles and the colloidal anionic silica-based particles are present in the aqueous composition in an amount of at least 0.1% by weight, based on the total weight of the aqueous composition.
24. The process according to claim 23 , wherein the anionic organic polymeric particles and the colloidal anionic silica-based particles are present in the aqueous composition within a range of 1 to 45% by weight, based on the total weight of the aqueous composition.
25. The process according to claim 20 , wherein the cationic polymer is added in an amount of 0.1 to 50 kg/t counted as dry substance based on dry pulp and optional filler.
26. The process according to claim 20 , wherein the cationic polymer is added before the addition of the aqueous composition.
27. The process according to claim 26 , wherein the cationic polymer is added before a shear stage and the aqueous composition is added after that shear stage.