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US 10,280,258 B2Granted
Method for producing oxymethylene copolymer
AssigneeMitsubishi Gas Chemical Company, Inc.
InventorsDaigo Nakaya, Toru Takahashi, Satoshi Mochida
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Abstract
The present invention provides a method for producing an oxymethylene copolymer which involves polymerizing trioxane and a comonomer cationically at a polymerization temperature of 135° C. to 300° C. in the presence of a protic acid salt having the molecular weight of 1000 or less, and at least one polymerization initiator selected from the group consisting of protic acids, protic acid anhydrides, and protic acid ester compounds having the molecular weight of 1000 or less.
Claims11
A method for producing an oxymethylene copolymer, the method comprising:
- cationically polymerizing trioxane and a comonomer at a polymerization temperature of 140° C. to 165° C. in the presence of at least one protic acid salt selected from the group consisting of perchloric acid salts and at least one polymerization initiator selected from the group consisting of perchloric acid, acid anhydrides thereof, and ester compounds thereof, and
- charging at least one polymerization terminator;
- wherein the content of the at least one polymerization initiator is 0.01 ppm by mass to 100 ppm by mass relative to the content of the trioxane, and the mole ratio of the at least one polymerization initiator to the at least one protic acid salt is in the range of 1:0.01 to 1:5;
- and
- wherein the polymerization reaction is performed while the polymerization temperature is maintained from charging of the at least one polymerization initiator till the charging of the at least one polymerization terminator so that a maximum temperature difference from the time of the charging the at least one polymerization initiator until the time of charging the at least one polymerization terminator is less than 20° C.
2 more elements
Dependencies are inferred from the claim text.