| 摘要 |
The invention relates to a process for obtaining grafted polyethers for flexible polyurethane foams, by grafted radical polymerization of some vinyl monomers, in a liquid medium consisting of polyol polyethers, homopolymers of the propylene epoxide or propylene epoxide-ethylene epoxide copolymers, with the role of a grafting support, and consists in adding to a first mixture comprising polyether, approximately 50...70% of the needed polyether, dispersion stabilizers and, as a chain transfer agent, amine polyol in concentrations of 2...10% in comparison with the finite polyether, under an inert nitrogen layer of 0.1...0.5 bars, at a temperature of 80...130 degree C, a second mixture at a low temperature of 5...30 degree C, consisting of polyether, in an amount of 30...50% of the needed polyether, dispersion stabilizers and amine polyol as a transfer agent, vinnyl monomers which represent 10...50% of the finite grafted polyether, preferably 50...100% phenyl ethylene and/or 0...100% acrylonitrile and radical initiator in a concentration of 2...8% in comparison with the vinnyl monomer sum, for 2...3 hours, followed by conducting the reaction for 1...1,5 h, at a temperature of 115...125 degree C, and by degassing the reaction mass at an underpressure of 2...200 mm Hg with continuous nitrogen bubbling for removing the unreacted monomers.
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