Process for preparation of oxymethylene polymers in a homogeneous phase, and use

A process for preparation of oxymethylene homopolymers of the formula I

• R1—(O—CH2)n—O—R2 (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 R1 and R2, 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 —CH2—O— units,
• ii) termination of the polymerization in a homogeneous phase prior to achievement of thermodynamic equilibrium conversion of the monomer which forms —CH2—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.