Patent ID: 6051634
Filing Date: 2000-04-18
Classification: C04B,C08G

Abstract:
A method for making a mineral building material comprising the steps of:(i) homogeneously mixing a water-dispersible or water-soluble polyether-urethane composition with an aggregate, a hydraulic inorganic binder, and water, the polyether-urethane composition comprising:a) an average isocyanate functionality of less than 1.8, a content of aliphatically and/or cycloaliphatically bonded isocyanate groups (calculated as NCO; molecular weight=42) from 0 to 10 wt. %,b) 2.0 to 25.0 wt. % content of urethane groups (calculated as NHCOO; molecular weight=59),c) 30 to 90 wt. % content of ethylene oxide units (calculated as C.sub.2 H.sub.4 O; molecular weight=44) bonded within polyether chains containing an average of 5 to 50 ethylene oxide units;(ii) hardening the mixture of step (i) to form the mineral building material,wherein the polyether-urethanes are prepared by reaction of (i) polyisocyanates which are based on aliphatic and/or cycloaliphatic diisocyanates, contain isocyanurate groups and have an isocyanate group content of 12 to 28 wt. % and a content of monomeric diisocyanates of less than 0.5 wt. % with (ii) polyether-alcohols having an average of 5 to 50 ethylene oxide units and optionally further compounds of the molecular weight range 32 to 300 which carry groups which are reactive with isocyanate groups are employed.