Oraganocarbonate-modified prepolymer, its use as a reactant for the preparation of isocyanate-free and isothiocyanate-free alkoxysilane polymers, and compositions thereof

A process for preparing an alkoxysilane polymer comprising:

• reacting a prepolymer comprising, at least on average, 1.5 carbonate groups of the formulae (I) and (II), 1.5 thiocarbonate groups of the formulae (Ia) and (IIa), 1.5 carbamate groups of the formulae (XI) and (XII), or 1.5 thiocarbamate groups of the formulae (XIa) and (XIIa)
• in which R1 and R2 independently of one another are linear or branched C1 to C6 alkyl, C1 to C6 acyl, C3 to C8 cycloaliphatic, C6 to C10 aryl or imide radicals or C3 to C6 alcohols,
• R11 and R12 and also R13 and R14 in each case together form heterocyclic ring systems which may be aromatic or nonaromatic and are independent of one another, and wherein these ring systems may contain further heteroatoms selected from the group of oxygen, nitrogen, and sulfur or may contain functional groups selected from the group of acyl and thioacyl,
• wherein the at least on average 1.5 carbonate, thiocarbonate, carbamate or thiocarbamate groups are bonded directly via one oxygen atom each to the polymer backbone of the prepolymer, this one oxygen atom each having its origin in the reaction of a primary, secondary or tertiary hydroxyl group of the polymer backbone and a reactive compound selected from the group consisting of a diorganocarbonate, a diorganothiocarbonate, a cyclic carbonate, a cyclic thiocarbonate, an N,N-diheterocyclourea derivative, and an N,N-diheterocyclothiourea derivative with:
• (A) an aminoalkoxysilane or a mercaptoalkoxysilane, optionally in the presence of a catalyst, or
• (B) a diamine, a triamine, a dithiol or a trithiol to give a modified prepolymer and subsequently carrying out reaction with an alkoxysilane compound comprising an epoxide group,
• to form the alkoxysilane polymer.