An object of the present disclosure is to provide a composition for use in sintered molded bodies which does not impair the shape retention ability of a green molded body relying on the rigidity inherent to a polyacetal resin, has high fluidity, and is resistant to cracking or swelling during degreasing. The composition for use in sintered molded bodies contains a sinterable inorganic powder and an organic binder, the organic binder contains at least a polyacetal resin and a polyolefin resin, and the melt flow index of the polyacetal resin is 70 to 200 g/10 min.

A molded body that can suppress plastic deformation during conveyance is provided. A molded body according to the present disclosure is a molded body containing a sinterable inorganic powder and an organic binder, wherein the bending modulus (MPa) upon 0.05% to 0.1% strain of the above molded body is 4000 to 15000, and the bending yield strength (MPa) is 10 or more.

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.

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.

The present invention provides a trioxane composition which comprises trioxane as a main component, an antioxidant, and at least one alkaline organic compound selected from the group consisting of an amine compound having an alcoholic hydroxy group in the molecule thereof, a thiocarbamate compound, and an organophosphorus compound, wherein the amount of the alkaline organic compound contained is 0.01 to 10 ppm, based on the trioxane, and wherein the trioxane composition is a liquid.

The present invention provides a trioxane composition which comprises trioxane as a main component, an antioxidant, and at least one alkaline organic compound selected from the group consisting of an amine compound having an alcoholic hydroxy group in the molecule thereof, a thiocarbamate compound, and an organophosphorus compound, wherein the amount of the alkaline organic compound contained is 0.01 to 10 ppm, based on the trioxane, and wherein the trioxane composition is a liquid.

The invention provides a method for producing an oxymethylene copolymer including a polymerization step for cationically polymerizing trioxane and a comonomer at a polymerization temperature of from 135 to 300 C. in the presence of at least one salt of a protonic acid having a molecular weight of 1,000 or less, and at least one polymerization initiator selected from the group consisting of protonic acids having a molecular weight of 1,000 or less, protonic acid anhydrides having a molecular weight of 1,000 or less, and protonic acid ester compounds having a molecular weight of 1,000 or less; wherein the total concentration of metal components contained in the trioxane and comonomer used in the polymerization step is 300 ppb by mass or less.

The invention provides a method for producing an oxymethylene copolymer including a polymerization step for cationically polymerizing trioxane and a comonomer at a polymerization temperature of from 135 to 300 C. in the presence of at least one salt of a protonic acid having a molecular weight of 1,000 or less, and at least one polymerization initiator selected from the group consisting of protonic acids having a molecular weight of 1,000 or less, protonic acid anhydrides having a molecular weight of 1,000 or less, and protonic acid ester compounds having a molecular weight of 1,000 or less; wherein the total concentration of metal components contained in the trioxane and comonomer used in the polymerization step is 300 ppb by mass or less.

The present invention provides a trioxane composition which comprises trioxane as a main component, an antioxidant, and at least one alkaline organic compound selected from the group consisting of an amine compound having an alcoholic hydroxy group in the molecule thereof, a thiocarbamate compound, and an organophosphorus compound, wherein the amount of the alkaline organic compound contained is 0.01 to 10 ppm, based on the trioxane, and wherein the trioxane composition is a liquid.

The present invention provides a trioxane composition which comprises trioxane as a main component, an antioxidant, and at least one alkaline organic compound selected from the group consisting of an amine compound having an alcoholic hydroxy group in the molecule thereof, a thiocarbamate compound, and an organophosphorus compound, wherein the amount of the alkaline organic compound contained is 0.01 to 10 ppm, based on the trioxane, and wherein the trioxane composition is a liquid.