Patent ID: 9605382
Date: 2017-03-28
CPC Classifications: D21H

Claim:
1. 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.