METHOD OF PRODUCING ADDITIONALLY CROSS-LINKED WATER-ABSORBING POLYMER PARTICLES WITH HIGH ABSORPTION BY POLYMERISING DROPLETS OF SOLUTION Russian patent published in 2013 - IPC C08F20/04 A61L15/22 

FIELD: chemistry.

SUBSTANCE: described are water-absorbing polymer particles with centrifugal retention capacity (CRC) of at least 20 g/g and absorptionm under a load of 4.83 kPa (AUL0.7psi), which satisfy the condition AUL0.7psi≥-0.017CRC²+1.5CRC-6. The polymer particles have average sphericity of at least 0.84 and hydrophobic solvent content of less than 0.005 wt %. Also described are water-absorbing polymer particles with average sphericity of at least 0.84, hydrophobic solvent content of less than 0.005 wt %, and CRC of at least 20 g/g and free swell rate (FSR) which satisfies the condition FSR≥ -0.00082 CRC²+0.07CRC-0.95. Described is a method of obtaining said particles by polymerising droplets of a monomer solution which contains a) at least one at least one ethylenically unsaturated monomer having at least one acid group, b) at least one cross-linking agent, c) at least one initiator, d) water in the gas phase surrounding the droplets, the obtained polymer particles being additionally cross-linked, wherein content of solid substance of the monomer solution is at least 35 wt %, and the monomer solution is added in droplets to the gas phase to form a monodispersion droplet chain, and wherein the polymer particles have mean diameter of at least 150 mcm, wherein the process is carried out, if necessary, in the presence of a hydrophobic solvent. Use of said polymer particles to obtain sanitary and hygiene products is also described.

EFFECT: obtaining water-absorbing polymer particles with an improved profile of characteristics, high permeability, high centrifugal retention capacity, high absorption under load and high free swell rate.

27 cl, 1 dwg, 3 tbl, 9 ex