Polyoxymethylene multi-block copolymers, their production and use

Multiblock copolymers are described and contain the structural unit of formula I -A-O-R1-O-CO-(R2-CO-)m-X-D-X-(CO-R2)m-CO-X- (I), where A is a radical derived from a homo- or copolyoxymethylene, R1 is an alkylene radical-having at least two carbon atoms or a cycloalkylene radical, R2 is a direct carbon-carbon bond, or an alkylene, cycloalkylene, arylene, or aralkylene radical, X is selected from -O-, -S-, or -NH-, D is a divalent radical B which is a radical of a hydroxy-terminated, mercaptan-terminated, or amino-terminated polymer which derives from polyalkylene glycols, polyvinyl ethers, polyvinyl ether-alkene copolymers, polyvinyl esters, polyvinyl ester-alkene copolymers, polyvinyl alcohols, polyvinyl alcohol-alkene copolymers, polyvinylaromatics, polyacrylates, polymethacrylates, polyacetals, polycarbonates, polyesters, polyamides, polyimines, polyetherester elastomers, polyetheramide elastomers, polyalkadienes, polyurethanes, polyureas, polysiloxanes, or a triblock copolymer radical -PAO-B-PAO-, where B assumes one of the above meanings and PAO is a polyalkylene oxide radical, and m is 0 or 1. The multiblock copolymers may be used to produce moldings.