| abstract |
Polyurethane/ureas including hydrophilic moieties and alkoxysilane groups of formula (I)n n—X—CO—NR 2 —Y—Si-(Z) 3 ( 1 )n nwhere X is O or NR 2 ; R 2 is H, C 1 -C 6 alkyl, substituted C 1 -C 6 alkyl, cycloalkyl, aryl or benzyl; Y is C 1 -C 8 linear and branched alkylene; and Z is an organic group inert to isocyanate groups below 100° C. At least one Z group is an alkoxy group of 1 to 4 carbon atoms. The polyurethane/urea can be in an aqueous dispersion, which can be used to prepare coatings. The dispersion is prepared by n(ii) reacting an organic polyisocyanate with a high molecular weight polyol, optionally a low molecular weight isocyanate-reactive compound, an isocyanate-reactive compound containing hydrophilic groups, and/or an amine chain extender forming a prepolymer; (ii) reacting the prepolymer in (i) with a compound of formula (II)n nOCN—Y—Si-(Z) 3 (II)nwhere Y and Z are as defined; and (iii) dispersing the reaction product in (II) in an aqueous medium. |