NEW POLYACETAL PROCESS FROM FORMALDEHYDE POLYMERIZATION IN THE PRESENCE OF A CHAIN TRANSFER AGENT

A new polyacetal process from formaldehyde polymerization in the prese nce of a chain-transfer agent was developed. For the acetal homopolyme r, highly purified formaldehyde is polymerized in the presence of acet ic anhydride. Thus, an end-capped polymer can be obtained during polym erization. This concept gave us a very simple process for manufacturin g the acetal homopolymer, compared to the conventional process. If tri functional or tetrafunctional alcoholic compounds are used as chain-tr ansfer agents, branched poly(oxymethylene) is obtained; the melt visco sity of this branched poly(oxymethylene) shows a higher pressure depen dence than the linear poly(oxymethylene). If a functional polymer is u sed as the chain-transfer agent, which has an active hydrogen, the ace tal block copolymer, which shows characteristic properties, can be obt ained.