Patent ID: 8906192

Claim:
A method of preparing a polyurethane with polyurethane-polyether and polyurethane-polyester blocks comprising at least 2 end blocks each consisting of a polyurethane-polyester block joined to an alkoxysilane end group, said method comprising the sequential steps of: (i) reaction of a mixture of alcohols comprising a polyether polyol (A) with a stoichiometric excess of an aliphatic diisocyanate or an aromatic diisocyanate (B) of the formula: NCO—R 1 —NCO (I) in which R 1 represents a divalent aliphatic or aromatic hydrocarbon radical comprising 5 to 15 carbon atoms which is linear, branched or cyclic, to form a polyurethane-polyether block possessing at least 2 —NCO end groups, then (ii) reaction of the polyurethane from (i) with a stoichiometric excess of a polyester polyol (C), to form a polyurethane with polyurethane-polyether and polyurethane-polyester blocks comprising at least 2 end blocks each consisting of a polyurethane-polyester block joined to an —OH end group, then (iii) reaction of the polyurethane with —OH end group from (ii) with a stoichiometric amount of an isocyanatosilane (D).