Societa' Italiana Resine S.i.r. S.p.a.

Daniele Colombo

Pierino Radici

Paolo Colombo

Gaudenzio Bianchi

Block copolymer of the structure A-B, wherein: ##STR1## A is a polylactamic block of recurring units: t,0010 WHEREIN PM is a linear polymethylene chain having from 3 to 13 carbon atoms, B is a polyoxymethylene block of recurring units [CH.sub.2 O]. The block copolymer contains at least 2 wt.% of block B and at least 0.05 wt.% of block A. The block copolymer can be used as technopolymer when rich in block B, or in the field of yarns and molded products when rich in block A.

Block copolymers

A novel block copolymer HO--D--A--B--D--H, wherein

Polyformaldehyde is prepared by feeding anhydrous formaldehyde to a reaction medium containing a liquid organic diluent non-solvent for the polyformaldehyde and non-reactive towards the other constituents of the reaction medium, and containing in a dispersed form a copolymer A-B, wherein A is a polylactonic block of recurring units ##EQU1## B is a polylactamic block of recurring units ##EQU2## wherein PM.sub.1 and PM.sub.2 are linear polymethylene chains having from 2 to 13 and 3 to 13 carbon atoms, respectively.

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Castellanza (Varese), Italy

Daniele Colombo