Process for producing polyacetal copolymer
AssigneePolyplastics Co., Ltd.
InventorsKaoru Yamamoto, Akira Nakai
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Abstract
To economically produce a polyacetal copolymer excellent in properties including thermal stability by copolymerizing trioxane as the main monomer through simple steps, a polyacetal copolymer is produced by copolymerizing trioxane as the main monomer using a nonvolatile protonic acid catalyst as a polymerization catalyst until the conversion reaches at least 60% (based on all monomers), and then vaporizing unreacted monomers to separate, remove, and recover the same from the polymerization system to thereby reduce the residual monomer content of the polymerization system to 5% by weight or lower.
Claims29
A process for producing a polyacetal copolymer comprising the steps of:
- (A) copolymerizing, under polyacetal copolymerization conditions, a polymerization system comprised of trioxane monomer with a cyclic ether or a cyclic formal having at least one carbon--carbon bond in the presence of a protonic acid polymerization catalyst which is non-vaporizable under conditions of steps (A), (B) and (C), until reaching a polymerization degree of at least 60%, based on all monomers, to thereby obtain a reaction product mixture comprised of crude polyacetal copolymer, unreacted monomers and polymerization catalyst, and then subsequently
- (B) causing the unreacted monomers in the reaction product mixture to vaporize, and
- (C) separating the vaporized unreacted monomers from the reaction product mixture to thereby reduce the remaining monomer content thereof to 5% by weight or less based on the weight of the crude polyacetal copolymer therein.
Dependencies are inferred from the claim text.