A composition includes: a metal compound; a compound having an oxymethylene structure; and a solvent. The metal compound is a metal salt or a metal complex. The compound having an oxymethylene structure is capable of generating an aldehyde structure when degraded through heating. A metal atom contained in the metal compound preferably belongs to any one of periods 3 to 7 among groups 2 to 14 in a periodic table.

A composition includes: a metal compound; a compound having an oxymethylene structure; and a solvent. The metal compound is a metal salt or a metal complex. The compound having an oxymethylene structure is capable of generating an aldehyde structure when degraded through heating. A metal atom contained in the metal compound preferably belongs to any one of periods 3 to 7 among groups 2 to 14 in a periodic table.

The present invention provides a powdery material for a 3D printer from which a high-density and high-strength three-dimensional shaped object having an excellent appearance can be fabricated, a three-dimensional shaped object obtained by using the same, and a production method therefor. The powdery material (X) for a 3D printer is a powdery material (X) comprising a polyacetal copolymer resin powder (I), wherein a percentage occupied by comonomer units among all constituent units (100 mass %) in the polyacetal copolymer resin is at least 1.0 mass % and at most 6.0 mass %, an average particle diameter of the powder (I) is at least 30 m and at most 70 m, and a melt flow rate of the powder (I) measured at a temperature of 190 C. and with a load of 2.16 kg is at least 1.0 g/10 min and at most 8.0 g/10 min.

The present invention provides a powdery material for a 3D printer from which a high-density and high-strength three-dimensional shaped object having an excellent appearance can be fabricated, a three-dimensional shaped object obtained by using the same, and a production method therefor. The powdery material (X) for a 3D printer is a powdery material (X) comprising a polyacetal copolymer resin powder (I), wherein a percentage occupied by comonomer units among all constituent units (100 mass %) in the polyacetal copolymer resin is at least 1.0 mass % and at most 6.0 mass %, an average particle diameter of the powder (I) is at least 30 m and at most 70 m, and a melt flow rate of the powder (I) measured at a temperature of 190 C. and with a load of 2.16 kg is at least 1.0 g/10 min and at most 8.0 g/10 min.