| 摘要 |
<PICT:1074252/C3/1> An apparatus comprising a screw press with a diminishing screw and interruptions therein to accomodate teeth projecting inwardly from the casing wall (see Divisions B1-B2) may be used to form solid oxymethylene polymers from a mixture containing at least 50% by weight of trioxane alone or with comonomers. In an example trioxane, a cyclic ether such as 1,3-dioxolane or ethylene oxide, a solvent such as cyclohexane and a chain transfer agent such as methanol or methylal are fed to the apparatus separately or as mixtures; the catalyst which is preferably a boron fluoride-ester complex such as boron fluoride dibutyl etherate may be fed separately. The mass is maintained at a temperature between 0 DEG and 116 DEG C. and discharged as a dry powdered solid after a reaction time of 0.5-2 minutes. The product may be treated with a catalyst deactivator such as water or an aliphatic amine.
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