Kemira Oyj

Pulp and Paper Research Institute of Canada

Marco Polverari

Matti Hietaniemi

Sacha Legrand

Christopher Michael Lewis

Matthew Gerard Fabian

Asko Karppi

Anneli Lepo

Rosa Carceller

Lawrence Harvey Allen

Michael P O'Toole

Joonas Hokka

Gunar V Laivins

New polyvinylamide and/or acryl acid-based copolymers. The new structured block copolymers are based on the block copolymerization of N-vinyl formamide (NVF) with other monomers by using a bifunctional initiator. Further, a method of preparing the structured block copolymer is provided, and especially a method wherein the NVF-based block is at least partially hydrolyzed to obtain PVAm. Also the use of the new structured block copolymers in sludge dewatering and in papermaking processes is disclosed.

Structured block copolymers

The invention relates to a papermaking agent composition, preferably in powder form, which comprises a water-soluble polymer, which comprises 21-30 mol-% of vinylamine units and has an average molecular weight of at least 1 000 000 Da. The invention relates also to a method for treating of fiber stock in manufacture of paper, board or the like, where a thick fiber stock is obtained, it is diluted to a thin fiber stock having a consistency &#x3c;3% by addition of water, and the thin fiber stock is drained and a continuous fibrous web is formed. The papermaking agent composition is added to the thick fiber stock or to the thin fiber.

Papermaking agent composition and method for treating fibre stock

The invention relates to a papermaking agent system in liquid form, which comprises (i) cationic starch solution, prepared by cooking a starch mixture comprising a starch component and a water component, and (ii) polymer composition, which has anionic and cationic groups and a cationic net charge of &#x3e;0.1 meq/g. The polymer composition comprises or originates from at least one of constituents a), b) or c). Constituent a) contains an amphoteric polymer, which is a copolymer comprising structural units derived from acrylamide and/or methacrylamide monomers, and anionic and cationic groups attached to the copolymer. Constituent b) contains a first polymer, which is a copolymer comprising structural units derived from acrylamide and/or methacrylamide monomers, and anionic or cationic groups attached to the copolymer, as well as a second polymer, which comprises groups with opposite charge than the first polymer. Constituent c) contains a third polymer, which comprises a copolymer comprising structural units derived from acrylamide and/or methacrylamide monomers, as well as hydrolytically unstable cationic groups attached to the copolymer. Constituent a), b) or c) is added to one of the components of the starch mixture or to the starch mixture before the cooking of the starch mixture, and/or constituent a) or b) is added to the cationic starch solution after cooking of the starch mixture. The invention relates also to the use of the papermaking agent system and to a method for its preparation.

Papermaking agent system, method for making a papermaking agent system and its use

A composition includes a dispersion, having an aqueous phase containing a dissolved water soluble cationic coagulant polymer and if needed a dissolved inorganic salt. The aqueous phase further contains a dispersed water soluble flocculant polymer, wherein the water soluble flocculant polymer is formed of a water soluble ethylenically unsaturated monomer or monomer blend which are polymerized in the aqueous phase. The water soluble cationic coagulant polymer is cationic poly(alkyleneamine), which is the reaction product of the following reaction:HN&#x2014;(CH)&#x2014;NR&#x2014;(CH)&#x2014;NH+Cl&#x2014;CHCH&#x2014;Cl,

Polymeric compositions and their production and uses

According to the present invention, a process is provided for making paper or board comprising forming a cellulosic suspension that may or may not comprise a filler, flocculating the cellulosic suspension, draining the cellulosic suspension on a screen to form a sheet, wherein the cellulosic suspension is flocculated using a flocculation system comprising the sequential or simultaneous addition of a siliceous material and an organic, cationic or anionic, water-in-water or dispersion micropolymer in a salt solution.

Composition and method for paper processing

According to the present invention, a process is provided for making paper or board comprising forming a cellulosic suspension that may or may not comprise a filler, flocculating the cellulosic suspension, draining the cellulosic suspension on a screen to form a sheet, wherein the cellulosic suspension is flocculated using a flocculation system comprising the sequential or simultaneous addition of a siliceous material and an organic, cationic or anionic, dispersion micropolymer in a salt solution.

Method for paper processing

A papermaking stock and a method for improving the retention of pulp fines, mineral fillers, dispersed wood resin, and/or synthetic hydrophobic stickies and cellulose fibers in a cellulosic fiber sheet, employs dendrimeric polymers for increasing the retention of fines, fillers, dispersed hydrophobic particles, and cellulosic fibers. The application in the paper industry provides a means of (1) increasing the retention of fillers in paper and decreasing the loss of filler materials in white water waste from papermaking; (2) increasing the retention of cellulosic fines and fibers in the paper-making process; increasing drainage on the paper machine; and (3) removing a significant fraction of the wood resin, plastics, and stickies from the process stream thus enabling a greater extent of reuse of filtrates and, hence, less effluents from mills, fewer problems from wood resins such as deposit formation, loss of strength of product, and contamination of product with dirt particles.

Dendrimeric polymers for the production of paper and board

A process is disclosed for the production of paper and paper-like products from a suspension of papermaking materials to which poly(ethylene oxide) and a phenolic type cofactor which may be produced by a Williamson synthesis from a resin, are added to improve the retention of fibers, of fines, of dispersed extractives and of fillers during the processes of water removal for the manufacturing of paper.

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Montreal, Canada

Marco Polverari