Modifying hydraulic binders contg. calcium sulphate - by mixing binder and/or the mixing water with water-soluble isocyanate-polyether prepolymers

摘要

CaSO4-based hydraulic binders are modified by admixing the powdery binder and/or the mixing water with 3-30 (5-15) wt. % (w.r.t. binder) of water-soluble, at least bifunctional isocyanate-polyether prepolymers having mol. wts. 800-10000 (1600-8000). Modified hardened layers and/or articles can be used as (i) insulators, joints or cavity fillers in building; (ii) for prodn. of light-weight, non-brittle, non-chalking articles; (iii) for prodn. of soil-improving granulates; (iv) as carriers for perfumes and pesticides and (v) for absorbing liquids, e.g. oil. (I) modify hydraulic binders in a way such that layers and/or articles combine low specific wt.; soft, nonbrittle nature; high insulating power when dry and high water-absorption and -retention. (I) can be used directly, without further solvents. (I) may be used which can form highly crosslinked end polymers during reaction in aq. medium. Use of (I) contg. -NCO end-gps., reacting with water with CO2 dissociation, leads to light, expanded articles.