Patent RU-2518063-C2 (RU)
Inventor: TIAN GONGLU
IPC: C08F6/00
Filed: 2009-10-13
Granted: 2014-06-10
Abstract: FIELD: chemistry. 
     SUBSTANCE: claimed invention relates to obtaining superabsorbing polymer particles. Described are versions of producing superabsorbing polymer composition with recycled superabsorbing polymer finely crushed particles, including the following stages: a) processing superabsorbing polymer finely crushed particles, which have the average particle size less than about 150 mcm with caustic solution, containing from about 0.1 to about 12% of caustic relative to the mass of superabsorbing polymer finely crushed particles, where caustic is selected from sodium hydroxide, sodium carbonate or sodium bicarbonate; b) mixing processed superabsorbing polymer finely crushed particles, obtained at stage a), with polymerisation solution, containing at least one cross-linking agent and partially neutralised monomer, where said monomer solution includes initiator, in which content of superabsorbing polymer finely crushed particles relative to the total amount of monomer constitutes from about 0.1 to about 30 wt %; c) polymerisation of mixture, obtained at stage b), with obtaining superabsorbing polymer gel, and where said polymer represents cross-linked polymer from polyacrylic acid, sodium polyacrylate or their copolymers; d) crushing superabsorbing polymer gel, obtained at stage c); e) drying said crushed polymer gel; f) separation of said dried gel, obtained at stage e) into part, which has desirable size of particles from about 150 mcm to about 850 mcm, thus forming superabsorbing polymer particles; g) coating said particles of superabsorbing polymer, obtained at stage f), with surface cross-linking agent and surface additives; h) heating said coated polymer; and i) separation of said dried superabsorbing polymer particles, obtained at stage h) into part, which has desirable size of particles from about 150 mcm to about 850 mcm, thus forming target superabsorbing polymer composition. Described is superabsorbing polymer composition, possessing superabsorbent properties, obtained by the method, described above. Described is method of recycling superabsorbing polymer finely crushed particles in production of superabsorbing polymer composition, which includes the following stages: a) processing superabsorbing polymer finely crushed particles, which have the average particle size less than about 150 mcm with caustic solution, containing from about 0.1 to about 12% of caustic relative to the mass of superabsorbing polymer finely crushed particles, with caustic being selected from sodium hydroxide, sodium carbonate or sodium bicarbonate; b) mixing processed superabsorbing polymer finely crushed particles, obtained at stage a), with polymerisation solution, containing at least one cross-linking agent and partially neutralised monomer, in which content of superabsorbing polymer finely crushed particles relative to the total amount of monomer constitutes from about 0.1 to about 30 wt %, with said monomer solution including initiator; c) polymerisation of mixture, obtained at stage b), with obtaining superabsorbing polymer gel, with said polymer representing cross-linked polymer from polyacrylic acid, sodium polyacrylate or their copolymers; d) crushing superabsorbing polymer gel, obtained at stage c); e) drying said crushed polymer gel; f) separation of said dried gel, obtained at stage e) into part, which has desirable size of particles from about 150 mcm to about 850 mcm, thus forming superabsorbing polymer particles; g) coating said particles of superabsorbing polymer, obtained at stage f), with surface cross-linking agent and surface additives; h) heating said coated polymer; and i) separation of said dried superabsorbing polymer particles, obtained at stage h) into part, which has desirable size of particles from about 150 mcm to about 850 mcm, thus forming target superabsorbing polymer composition. 
     EFFECT: obtaining composition of superabsorbing polymer particles, obtained by method, including recycling of superabsorbing polymer finely crushed particles, with composition possessing improved absorbing ability and improved gel layer permeability. 
     13 cl, 4 dwg, 4 tbl, 10 ex