Process for preparation of oxymethylene polymers, selected polymers, and their use
AssigneeTicona LLC
InventorsMichael Haubs, Joachim Clauss, Michael Hoffmockel, Jurgen Lingnau, Arnold Schneller
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Abstract
An apparatus is described for preparation of oxymethylene homo- and copolymers. This encompasses heterogeneous polymerization of a monomer which forms oxymethylene groups in the presence of an acetal of formaldehyde and of an initiator for cationic polymerization, followed by the deactivation of the polymer in a homogeneous phase via treatment with a basic aprotic solvent or with an aprotic solvent which comprises a base. Oxymethylene homopolymers with very high stability are also described.
Claims22
A process for preparation of oxymethylene homopolymers of the formula I
- R1—(O—CH2)n—O—R2 (I)
- 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) heterogeneous polymerization, in the presence of an acetal of formaldehyde and of an initiator for cationic polymerization, of a monomer which forms —CH2—O— units, and
- ii) deactivation of the initiator and/or of the active polymer chains by using, for treatment in a homogeneous phase of the polymer prepared in step i), an aprotic solvent which is basic and/or which comprises a dissolved base.
A process for preparation of oxymethylene copolymers containing the structural units of the formulae II and III, and also end groups of the formula IV
- or containing the structural units of the formulae II and V, and optionally formula IV, and also end groups of the formula IV
- in which R1 is an alkyl radical,
- m is a whole number from 1 to 1000,
- o is a whole number from 2 to 6,
- p is a whole number from 3 to 6, and
- R3 is a p-valent organic radical
- encompassing the following measures:
- iii) heterogeneous polymerization of a monomer which forms —CH2—O— units and simultaneously of a monomer which forms —O—CoH2o— units, in the presence of an acetal of formaldehyde and of an initiator for cationic polymerization, or heterogeneous polymerization of a monomer which forms —CH2—O— units and simultaneously of a monomer which forms —O—(R3—O)p— units and, optionally simultaneously of a monomer which forms —O—CoH2o— units, in the presence of an acetal of formaldehyde and of an initiator for cationic polymerization, and
- iv) deactivation of the initiator and/or of the active polymer chains by using an aprotic solvent which is basic and/or which comprises a dissolved base, for treatment in a homogeneous phase of the polymer prepared in step i).
An oxymethylene homopolymer which, if appropriate, has up to 0.5% by weight of copolymerized oxyethylene units and/or up to 1% by weight of copolymerized branching agents, in which at least 95% of all of the end groups are alkoxy radicals, and whose decomposition rate, measured at 222° C., is less than 0.005% by weight/minute.
(canceled)
Dependencies are inferred from the claim text.