Polycarbodiimide-based block copolymers, a method of preparing them and their use as hydrolysis stabilizers

A hydrolysis stabilizer in ester-group-containing polymers comprising polycarbodiimide-based block copolymers of formula (I),

• X—[—(A)m—(B)n—]o—X (I),
• wherein
• X is identical or different and is selected from the group consisting —NHCO—R, —NHCONH—R, —NHCOO—R, —NHCOS—R, —COO—R, —O—R, —NR2, —S—R, —OH, —NH2, —NHR and —NCO, and wherein the group R denote an alkyl, cycloalkyl, aralkyl or aryl radical containing 1 to 30 carbon atoms,
• m, n are, independently of one another an integer from 1 to 1000,
• o is an integer from 1 to 500,
• A is selected from the group consisting of the carbodiimides or polycarbodiimides of formula (II)
• —(—N═C═N—Y—)— (II),
• wherein
• Y is selected from the group consisting of ortho- or bisortho-substituted aromatics, aralkylenes in which the carbon atom linked to the carbodiimide group is substituted by C1- to C14-alkyl groups, and cycloalkylenes in which the carbon atom linked to the carbodiimide group is substituted by C1- to C14-alkyl groups, and
• B is selected from the group consisting of (poly)dioles, (poly)diamines, (poly)dimercaptans, (poly)aminoalcohols, (poly)aminomercaptans and (poly)mercaptoalcohols.