| 摘要 |
The process comprises copolymerizing a mixture of a cyclic oligomer of formaldehyde or a cyclic acetal as the principal monomer with a comonomer copolymerizable therewith, in the presence of a perfluoroalkylsulfonic acid or a perfluoroalkylsulfonic acid derivative as the polymerization catalyst in an amount of 1x10<-><6>- 2x10<-><5>% by mole relative to the principal monomer. The content of water and formic acid in the monomer mixture are, respectively, not more than 40 ppm by weight. The polymerization catalyst in the resulting copoloymer is deactivated by adding and melt-blending at least one ion adsorbent selected from (a) ion adsorbents comprising as the main components at least two kinds of oxides selected from alkali metal oxides, alkaline earth metal oxides, and oxides of trivalent and tetravalent elements, or (b) ion adsorbents represented by the formula M11-xM2x(OH)2A<n->x/n.mH20 wherein M1 denotes at least one divalent metal selected from alkaline earth metals, M2 denotes a trivalent metal, A<n->denotes an n-valent anion, x satisfies 0< x </= 0.5, and m is a positive number, in an amount of 0.001-0.5% by weight relative to the polymer to obtain the polyoxymethylene copolymer composition. |
