Ticona Gmbh

Michael G Yearwood

Robert M Gronner

Satyajit Verma

Michael Hoffmockel

Karl-Friedrich Muck

Michael Haubs

Jürgen Lingnau

Horst Röschert

Karl-Friedrich Mück

Gerhard Reuschel

Peter Eckardt

Oxymethylene copolymers having a high proportion of terminal alkyl ether groups and having terminal hydroxyalkylene groups are described. These polymers are distinguished by high thermal stability and high hot water resistance. Furthermore, a process for the preparation of oxymethylene copolymers is described in which the polymerization of at least one monomer forming &#x2014;CH&#x2014;O&#x2014; units is effected in the presence of at least one acetal of formaldehyde and of at least one initiator of cationic polymerization and the initiator of cationic polymerization is used in an amount of less than or equal to 10mol %, based on the amount of the monomers present at the beginning of the polymerization and forming &#x2014;CH&#x2014;O&#x2014; units, in which starting materials of the polymerization are used such that the content of water and formic acid at the beginning of the polymerization is less than or equal to 40 ppm, and in which the initiator and/or the active polymer chains are deactivated by treatment of the prepared polymer with a base-containing protic solvent.

Oxymethylene copolymers and the use thereof and process for the preparation of oxymethylene copolymers

A process for the preparation of polyoxymethylene copolymers, wherein 1,3,5-trioxane is polymerized with generally known comonomers in the presence of a strong protonic acid initiator and in the presence of a formaldehyde dialkyl acetal, and wherein the initiator is dissolved in the formaldehyde dialkyl acetal before admixing to the trioxane and the comonomers.

Process for the preparation of thermally stable polyoxymethylene copolymers

Process for the preparation of thermally stable polyoxymethylene

A continuous process for the preparation of polyacetal copolymers from 1,3,5-trioxane and the comonomers known for this purpose using strong protic acids as an initiator, in which the initiator is added in an amount of 0.01 to 0.6 ppm, based on the total amount of monomers, in finely divided form to the monomer mixture, after the polymerization step the crude polymer is transferred from the polymerization reactor to a mixing unit without further intermediate steps, excess monomer is removed from the crude polymer in the mixing unit or between polymerization reactor and mixing unit by applying reduced pressure and, if desired, generally customary stabilizers, assistants, fillers, reinforcing materials and/or colorants are incorporated into the polymer in the mixing unit.

Process for the preparation of polyacetal copolymers

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Nueces, TX, United States of America

Michael G Yearwood