Patent ID: 7943726

Claim:
A process for preparation of oxymethylene homopolymers of the formula I R 1 —(O—CH 2 ) n —O—R 2 (I), which may contain up to 0.5% by weight of copolymerized oxyethylene groups and/or up to 1% by weight of branching agents, in which R 1 and R 2 , independently of one another, are alkyl radicals and n is a whole number greater than or equal to 500, encompassing the following measures: i) in a homogeneous phase, in the presence of an acetal of formaldehyde and of an initiator for cationic polymerization, polymerization of a monomer which forms —CH 2 —O— units, ii) termination of the polymerization in a homogeneous phase prior to achievement of thermodynamic equilibrium conversion of the monomer which forms —CH 2 —O— units, the amount of monomer converted being less than 90% of the equilibrium conversion, the termination accomplished via iii) deactivation of the active polymer chains in a homogeneous phase, by bringing the polymer prepared in step i) into contact with an organic or inorganic base, which can be in either dissolved or dispersed form, deactivation occurring at a deactivation temperature of less than 150° C.