Method for producing oxymethylene copolymer
AssigneeMitsubishi Gas Chemical Company, Inc.
InventorsTakuya Okada, Daisuke Sunaga
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Abstract
A method for producing an oxymethylene copolymer which gives molded articles that are inhibited from emitting formaldehyde and can be reduced in yellowness is provided. In producing an oxymethylene copolymer, an effective polymerization initiator amount is regulated to a value within a given range, the amount being calculated from the amount of perchloric acid or a derivative thereof contained in the polymerization initiator and the amount of triethanolamine contained in all the monomers comprising trioxane and comonomers, which are starting materials for the copolymer.
Claims9
A method for producing an oxymethylene copolymer, comprising:
- preparing a polymerization initiator (A) containing perchloric acid or a derivative thereof;
- subjecting a copolymer starting material (C) containing trioxane and a comonomer, the copolymer starting material (C) being obtained by mixing the prepared polymerization initiator (A) and a composition (B) containing the trioxane, to a polymerization reaction at 65° C. to 125° C.;
- and
- adding a polymerization terminator (D) to a product obtained during the subjecting of the copolymer starting material (C) to the polymerization reaction at 65° C. to 125° C. to obtain a crude oxymethylene copolymer, wherein:
- the copolymer starting material (C) contains triethanolamine in an amount of 0.048×10−6 mol to 0.25×10−6 mol relative to 1 mol of all monomers that are the total of the trioxane and comonomer;
- and
- when the difference between the amount X of perchloric acid per 1 mol of all the monomers (mol/mol) and the amount Y of triethanolamine per 1 mol of all the monomers (mol/mol) is regarded as an effective polymerization initiator amount Z (mol/mol) and defined by formula (1) below, the effective polymerization initiator amount Z in the copolymer starting material (C) is from greater than 0 to 0.2×10−6
- Z=X−Y (1).
A method for producing an oxymethylene copolymer, comprising:
- preparing a polymerization initiator (A) containing perchloric acid or a derivative thereof;
- subjecting a copolymer starting material (C) containing trioxane and a comonomer, the copolymer starting material (C) being obtained by mixing the prepared polymerization initiator (A) and a composition (B) containing the trioxane, to a polymerization reaction at 65° C. to 125° C.;
- and
- adding a polymerization terminator (D) to a product obtained during the subjecting of the copolymer starting material (C) to the polymerization reaction at 65° C. to 125° C. to obtain a crude oxymethylene copolymer, wherein:
- the copolymer starting material (C) contains triethanolamine in an amount of 1.0×10−8 mol to 3.0×10−7 mol relative to 1 mol of the trioxane;
- and
- when the difference between the amount X of perchloric acid per 1 mol of all monomers (mol/mol) and the amount Y of triethanolamine per 1 mol of all the monomers (mol/mol) is regarded as an effective polymerization initiator amount Z (mol/mol) and defined by formula (1) below, the effective polymerization initiator amount Z in the copolymer starting material (C) is from greater than 0 to 0.2×10−6
- Z=X−Y (1).
Dependencies are inferred from the claim text.