Binders containing orthoester groups

摘要

Preparation of an allophante group containing bonding agent comprises reaction of one or more aliphatic and/or cycloaliphatic polyisocyanate with one or more polyorthoester, which shows at least one hydroxy functional group per molecule, to give polyurethane with isocyanate and total or partial conversion of the obtained polyurethane, where the bonding agent exhibits a polyorthoester group with free isocyanate. Independent claims are included for: (1) preparation of the polyorthoester comprising reacting one or more acyclic orthoester with low-molecular polyolene of a functionality of 4-8 and a number mediator molecular weight of 80-500 g/mol, optionally 1.3 diol, where the hydroxyl groups are separated by at least 3C group from triol and optionally in the presence of catalysts, and converting the obtained product with the polyisocyanate to give polyorthoester; and (2) the allophanate containing bonding agent, which is obtained by the above procedure.