US Patent 7795357 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, andm is 0 or 1.The multiblock copolymers may be used to produce moldings.