| 摘要 |
A process for producing linear or slightly branched 2-(C1 to C3-alkyl)- DELTA 2-oxazoline copolymers from more than 50 mole % of 2-(isopropyl- and/or n-propyl)- DELTA 2-oxazoline and less than 50 mole % of 2-(methyl- and/or ethyl)- DELTA 2-oxazoline, the copolymers having a viscosity number in the range of 35 to 70 ml/g which is easily reproducible from batch to batch, comprises polymerizing the corresponding monomers in the presence of a cation-active catalyst having an anion of slightly nucleophilic nature, wherein, 1. the monomers contain less than 200 mg of water per liter of monomer and less than 0.003% by weight of basic nitrogen, the monomers being obtained by specified purification operations: 2.1 the polymerization is discontinuous and is carried out in a stirring vessel having a reflux condenser adequately dimensioned to remove the heat of polymerization by evaporative cooling, 2.2 optionally, the polymerization is conducted in the presence of 10 to 50% by volume, referred to the volume of the mixture of monomers, of an inert organic solvent, 2.3 the polymerization is conducted in the temperature range of 120 DEG to 175 DEG C., and the temperature following the conversion of 90 mole % of the monomers does not exceed 165 DEG C., and 2.4 the polymerization is stopped in the conventional manner after 96 to 99.5 mole % of the monomers has been polymerized.
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