BRANCHED POLYOLS HAVING A STATISTICAL AVERAGE OF TWO OR MORE HYDROXYL GROUPS IN THE MOLECULE, PROCESS FOR THEIR PREPARATION AND USE THEREOF

摘要

Disclosed are branched polyols (A) having two or more hydroxyl groups per molecule prepared by providing a polyisocyanate (A1) containing per molecule two or more isocyanate groups and either two or more hard segments (a11) which as part of a thermoset three-dimensional network raise its glass transition temperature, or two or more soft segments which as part of a thermoset three-dimensional network lower its glass transition temperature; and reacting the polyisocyanate (A1) with a polyol (A2) in a molar ratio (A2):(A1) of ≧2 and an equivalent ratio of [X+OH]:NCO≧2; wherein polyol (A2) has the general formula I: X [—R(—OH)n]m, and the variables have the following definitions: n is a number from 1 to 5, m is 1 or 2, X is an isocyanate-reactive functional group, and R is a divalent to pentavalent organic radical, with the proviso that R comprises at least one hard segment (a11) if (A1) comprises soft segments.