FIELD: chemistry.
SUBSTANCE: invention relates to low-molecular weight polyacrylic acids and use thereof as dispersers. Method for preparing aqueous solutions of polymers of acrylic acid with average molecular weight from 3,500 to 12,000 g/mol by polymerisation of acrylic acid in mode using a radical initiator in presence of hypophosphite in water as a solvent, comprising: (i) loading water and optionally one or more ethylene-unsaturated comonomers, (ii) continuously supplying acrylic acid in an acidic non-neutralised form, optionally, one or more ethylene-unsaturated comonomers, aqueous solution of a radical initiator and an aqueous solution of hypophosphite, (iii) at end of supply of acrylic acid adding a base to aqueous solution, wherein content of comonomers in terms of total content of monomers does not exceed 30 wt%, method is characterised by that aqueous solution of total hypophosphite supply time, consisting of three successive time intervals ΔtI, Δt(II) and Δt(III), average feed rate during second period of time ΔtII above values of average feed rate during first and third time intervals Δt(I) and Δt(III).
EFFECT: technical result is obtained polymers provide excellent rheological properties of pulp with filler, providing suitability for transfer by pump, including after storage.
13 cl, 2 tbl, 10 ex
