Polyisocyanates or mixtures of polyisocyanates with estergroups, a process for the preparation of such isocyanates or such mixtures of polyisocyanates and their utilization for polyurethane lacquers

摘要

Novel polyisocyanates or mixtures of polyisocyanates with ester groups, characterised by … …  a) a content of aliphatically bonded isocyanate groups of 18 to 33, preferably 20 to 33, % by weight, …  b) an (average) NCO functionality of 4.1 to 10, preferably 5 to 8, and …  c) a viscosity of 200 to 2500, preferably 500 to 1000, mPa.s at 22 DEG C, … a process for the preparation of the abovementioned preferred polyisocyanates or polyisocyanate mixtures by reacting aliphatic isocyanatocarboxylic acid chlorides with sugars, or sugar alcohols, which have 5 and/or 6 hydroxyl groups which are present in silylated form, and the use of the novel polyisocyanates or polyisocyanate mixtures as isocyanate component in two-component polyurethane varnishes.