METHOD OF PREPARING AQUEOUS SOLUTIONS OF COPOLYMERS Russian patent published in 2009 - IPC C08F220/06 C08F222/02 

FIELD: chemistry.

SUBSTANCE: method is described for preparing aqueous solutions of copolymers, involving a fundamental step for copolymerisation of partially neutralised acrylic and maleic acid in the presence of hydrogen peroxide in amount of 2 to 4% of total mass of monomers at temperature ranging from 85 to 105°C in an aqueous medium, which is realised through gradual addition of an aqueous solution of hydrogen peroxide for 3 to 6 hours into an aqueous solution of partially neutralised maleic acid and simultaneous gradual addition of an aqueous solution of partially neutralised acrylic acid, or an aqueous solution of free acrylic acid, or aqueous solutions of free acrylic acid and a base, and subsequent addition of hydrogen peroxide for 30 to 60 minutes after completion of simultaneous addition of hydrogen peroxide and acrylic acid, and a step for pre-polymerisation by keeping the reaction mixture at polymerisation temperature, distinguished by that, the pre-polymerisation step is realised by keeping the reaction mixture at polymerisation temperature for 35 to 60 minutes, subsequent simultaneous addition of aluminium or potassium persulphate in amount ranging from 0.10 to 0.15% of total mass of monomers and subsequent keeping at polymerisation temperature for 45 to 90 minutes.

EFFECT: increased dispersion capacity of copolymers.

1 cl, 1 tbl, 8 ex