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US 9,605,382 B2Granted
Process for production of paper or board
AssigneeKemira Oyj
InventorMikko Virtanen
Life of this patent
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Abstract
The invention relates to a process for production of paper or board comprising providing a stock comprising cellulose fibers, adding a mixture comprising microfibrillated cellulose and a strength additive to the stock, adding a microparticle to the stock after the addition of said mixture, dewatering the stock on a wire to form a web, and drying the web.
Claims19
A process for production of paper or board comprising the steps of:
- a) providing a stock comprising cellulose fibers,
- b) preparing a premixture of microfibrillated cellulose (MFC) and a strength additive, wherein the strength additive comprises starch and at least one synthetic polymer selected from the group consisting of cationic polyacrylamide (C-PAM), anionic polyacrylamide (A-PAM), glyoxylated polyacrylamide (G-PAM), amphoteric polyacrylamide, polydiallyldimethylammonium chloride (poly-DADMAC), polyacrylic amide (PAAE), polyvinyl amine (PVAm), polyethylene oxide (PEO), and polyethyleneimine (PEI);
- c) adding the premixture into the stock,
- d) adding a microparticle selected from silica-based microparticle, a natural silicate microparticle, a synthetic silcate microparticle or a mixture thereof to the mixture of step c,
- e) dewatering the mixture of step d) on a wire to form a web, and
- f) drying the web.
3 more elements
Dependencies are inferred from the claim text.