Process for manufacturing paper and board
AssigneeNordkalk Oy AB
InventorsPentti Virtanen, Sakari Saastamoinen
Life of this patent
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Abstract
The present invention relates to a fibre product that contains pulp fibre or wood fibre, wherein filler particles are attached between the fibres and to the fibrils, part of the particles consisting of chemically structured kaolin agglomerates or granules, and a part consisting of carbonate that is formed from a corresponding oxide or hydroxide by means of carbon dioxide. The invention also relates to a manufacturing method of such a fibre product.
Claims20
A fibre product that contains pulp fibre or wood fibre, wherein filler particles are attached between the fibres and to the fibrils, part of them consisting of chemically structured kaolin agglomerates or granules, and part consisting of carbonate.
A method of manufacturing a fibre product comprising:
- adding an oxide or hydroxide to an aqueous solution to form a hydroxide slurry, and reducing the pH of the solution to a range of 6.0-8.3 by conveying carbon dioxide to the solution so that the content of the salts of carbonic acid formed from the carbon dioxide and the hydroxide slurry is at least 0.01%, calculated from the total weight of the solid matter of the solution, whereby a salt composition is formed;
- suspending kaolin sheets or stacks or both in water together with a binder, whereby a kaolin composition is formed;
- producing kaolin drops in a spray drier from the kaolin composition, which is formed from the kaolin sheets or stacks or both and contains the binder, whereby excess water also evaporates, whereby structured kaolin particles are formed, or forming these structured kaolin particles by means of a mixing technique from the kaolin sheets or stacks or both, which are in the form of the slurry in the salt composition described above or its dissolved portion, with the binder;
- admixing the formed structured kaolin particles together with the salt composition or its dissolved portion to a paper or board pulp, whereby a fibre dispersion is formed;
- and
- precipitating the carbonate from the salt composition into particles in the dispersion while the dispersion is filtered, pressed, and dried into paper or board.
Dependencies are inferred from the claim text.