INHIBITING GROWTH OF MICROORGANISMS IN PULP AND PAPER Russian patent published in 2011 - IPC C02F1/50 C02F1/76 A01N59/00 C02F103/28 

FIELD: chemistry.

SUBSTANCE: invention can be used in aqueous systems of paper production lines to inhibit growth of microorganisms. The composition for obtaining antimicrobial effect contains a biocide which contains a chlorine source and which releases free chlorine, urea and alkali in a concentration which is sufficient to ensure pH of the composition ranges from 12 to 13.5. The biocide used is sodium hypochlorite and the alkali used is sodium hydroxide. The amount of urea used is such that the molar ratio of chlorine to urea ranges from 2:1 to 1:2 in terms of Cl₂. The method of stabilising chlorine used as the biocide involves adding a source of free chlorine, urea and alkali simultaneously or separately, continuously or periodically at the same point of the stream of the production system at closely lying points while stirring. The method of improving whiteness of the paper obtained in the paper production system involves adding to that system one or more optical bleaching agents and said composition for obtaining antimicrobial effect.

EFFECT: invention provides high antimicrobial effect and improved inhibition of growth of microorganisms at parts of the paper-making process or in pulp while reducing consumption of chlorine-containing biocide, improved effect of bleaching agents and dyes and low corrosive effect of the composition on equipment.

21 cl, 6 tbl, 6 ex