Kemira Oy

Kemira Chemicals Oy

Lars Harald Petander

Jonni Ahlgren

Pirkko J Virta

Jussi Nikkarinen

Sirkka L Leppavuori

Olli J Jokinen

Hakan E Wikberg

Tore Anders Duvnas

Lauri J Teivainen

The invention relates to a process for preparing a cationically modified (meth)acrylamide polymer by the Mannich reaction. There is prepared in advance a stable aldehyde-secondary amine adduct, which is obtained as a reaction product of an aqueous solution of the secondary amine and an aqueous solution of the aldehyde, and which, after the formation of the adduct, is stabilized to endure storage, by lowering the pH of the mixture of 7 or below and/or by adding methanol, and the adduct thus prepared is added to an aqueous solution of the (meth)acrylamide polymer and the pH is adjusted to an alkaline level, whereupon modification occurs. The invention also relates to the use of the modified (meth)acrylamide polymer as a flocculation, retention or dewatering agent.

Process for preparing a cationically modified (meth)acrylamide polymer and use of the polymer

The invention relates to a process for the production of paper by adding to an aqueous fiber suspension, which possibly contains a filler, auxiliary agents for improving retention and/or dewatering, the auxiliary agents being a cationic long-chain polyacrylamide and an aluminum salt, and by dewatering the obtained fiber suspension during the sheet-forming stage. According to the invention, the said aqueous fiber suspension, possibly containing a filler, to which the cationic long-chain polyacrylamide has first been added, is subjected to shearing forces, whereafter there is added to it, directly before sheet forming, a polymeric aluminum salt or an aluminum salt, in which case a base or an acid is added, when necessary, to the said fiber suspension so that the pH be within the range 7-9 before the sheet forming, in which case aluminum hydroxy particles having anionic surface charges will be formed in situ.

Process for producing paper

In a paper-making method cellulose is suspended in water and the obtained pulp suspension is dewatered in order to form a fiber web or a fiber sheet, water being removed from a pulp suspension which contains an organic polymer and an inorganic oligomeric Ti, Zr, Sn or B compound.

Paper-making method and a combination of ingredients to be used in it

A wood perservative is disclosed which contains water, a copper and/or zinc complex or a copper and/or zinc complex together with a zirconium complex, dissolved in water, and an acid which stabilizes the said metals in wood. According to the invention there is used as the acid which stabilizes metals in wood an organic polymer which is soluble in water or forms micelles in water, contains acid groups, and penetrates wood at least partly. Phloroglucin derivatives of fern extract can be used in addition.

Growing community of inventors

Vaasa, Finland

Lars Harald Petander