Process for preparing NCO prepolymers that are stable against sedimentation and their use

摘要

A method for the production of sedimentation-stable NCO-terminated prepolymers based on polyether-carbonate polyols and 4,4~-diphenyl-methanedi-isocyanate (4,4~-MDI) involves mixing polyether-carbonate polyols of mol wt. 1000-4000 with polyol(s) such as butanediol, glycerol or polyglycols (38 types listed) before reaction with a stoichiometric excess of 4,4~-MDI. A method for the production of NCO-terminated prepolymers (I) based on polyether-carbonate polyols and 4,4~-diphenyl-methanedi-isocyanate, which are stable with regard to storage and sedimentation at room temperature (RT), involves (a) mixing polyether-carbonate polyols (mol. wt. 1000-4000) with polyol(s) selected from 1,2- or 1,3-propanediol, glycerol, 1,3-, 1,4- or 2,3-butanediol, 2-methylpropane-1,3-diol, 1,2-, 1,3-, 1,4- or 1,5-pentanediol, 2,2-dimethylpropane-1,3-diol, 2-methylbutane-1,4-diol, 1,1,1-trimethylolethane, 3-methylpentane-1,5-diol (and its isomers), 1,1,1-trimethylolpropane, 1,7-heptanediol, 2-ethyl-1,6-hexanediol, 1,9-nonanediol, 1,11-undecanediol, diethylene glycol, triethylene glycol, oligoethylene glycol, 2,2~-thiodiglycol, di and poly-glycols derived from 1,2-propylene oxide, propylene glycols, di-, tri- and tetra-butylene glycols, di-, tri- and tetra-hexyleneether glycols, 1,4- or 1,3-cyclohexanediol and reaction products of these compounds with ethylene and/or propylene oxide in mol ratios of (1:1)-(1:5), and (b) reacting ths mixture with a stoichiometric excess of 4,4~-diphenylmethanedi-isocyanate. An independent claim is included for (I) obtained by the method described above.