Powder material for 3D printer and three-dimensional molded object

Abstract

Provided are a powder material for a 3D printer that makes it possible to obtain a three-dimensional molded article having good appearance and mechanical characteristics and further having excellent heat resistance, and a three-dimensional molded object using the same.　A powder material (X) for a 3D printer contains polybutylene terephthalate resin powder (I). When measured by differential scanning calorimeter when the temperature was raised from 30°C to 260°C at a rate of 20°C / min, the polybutylene terephthalate resin powder (I) has an enthalpy of fusion ΔHm1 in the first run of 50 J / g or less and an enthalpy of fusion ΔHm2 in the second run of 30 J / g or more.

Description

Powder materials and three-dimensional objects for 3D printers

[0001] This disclosure relates to powder materials for 3D printers and three-dimensional objects.

[0002] 3D printers have become rapidly popular in recent years because they can create three-dimensional objects without using molds or large-scale melting equipment. Polybutylene terephthalate (PBT) resin has excellent mechanical properties, electrical properties, other physical properties, and chemical properties, as well as good processability, and is therefore widely used as an engineering plastic in various fields such as automotive parts and electrical and electronic equipment parts. The use of polybutylene terephthalate resin powder as a powder material for 3D printers is being considered. For example, Patent Document 1 describes a powder additive manufacturing powder containing polybutylene terephthalate having a predetermined particle size distribution and melting peak half-width in a DSC chart.

[0003] International Publication No. 2020 / 138188 Brochure

[0004] However, crystalline resins like PBT undergo solid-phase polymerization when subjected to heat treatment held near their melting point, resulting in a high intrinsic viscosity (IV) of the resin. This leads to undesirable changes in physical properties during three-dimensional molding, such as viscosity unevenness during melting and yellowing due to heating, making it difficult to obtain good appearance and mechanical properties. Furthermore, conventionally, powder materials containing polybutylene terephthalate resin powder for powder bed fusion (PBF) 3D printers have been devised to improve moldability by including copolymer components. However, improving moldability tends to decrease heat resistance and mechanical properties, and attempting to improve heat resistance and mechanical properties makes appearance defects more likely, making it difficult to satisfy all of these properties.

[0005] The object of this disclosure is to provide a powder material for 3D printers that can produce three-dimensionally molded products having good appearance, mechanical properties, and heat resistance, as well as three-dimensionally molded products using the same.

[0006] This disclosure includes the following embodiments: A powder material (X) for a 3D printer comprising a polybutylene terephthalate resin powder (I), wherein the enthalpy of melting ΔHm1 of the polybutylene terephthalate resin powder (I), measured by a differential scanning calorimeter, is 50 J / g or less when heated from 30°C to 260°C at a heating rate of 20°C / min, and the enthalpy of melting ΔHm2 measured in the second run is 30 J / g or more.

[0007] According to this disclosure, it is possible to provide a powder material for 3D printers and a 3D printed object using the same, which can be obtained by obtaining a 3D printed object that has a good appearance, mechanical properties, and excellent heat resistance.

[0008] One embodiment of the present disclosure will be described in detail below, but the scope of the present disclosure is not limited to the embodiment described herein, and various modifications can be made without departing from the spirit of the present disclosure. Each embodiment disclosed herein can be combined with any other features disclosed herein. If multiple upper and lower limits are given for a particular parameter, any combination of these upper and lower limits can be used to create a suitable numerical range. The lower and / or upper limits of the numerical ranges described herein may be replaced with numerical values ​​within that range, as shown in the examples. The expression "X to Y" indicating a numerical range means "X or greater and Y or less". If a particular description given for one embodiment also applies to other embodiments, that description may be omitted in the other embodiments.

[0009] [3D Printer Powder Material (X)] The first embodiment of this disclosure relates to a 3D printer powder material (X). The 3D printer powder material (X) according to the first embodiment (hereinafter referred to as "powder material (X)") comprises polybutylene terephthalate resin powder (I), wherein the enthalpy of melting ΔHm1 of the polybutylene terephthalate resin powder (I), measured by a differential scanning calorimeter, is 50 J / g or less when heated from 30°C to 260°C at a heating rate of 20°C / min, and the enthalpy of melting ΔHm2 measured in the second run is 30 J / g or more. According to a powder material (X) containing polybutylene terephthalate resin powder (I) in which both the enthalpy of fusion ΔHm2 measured by Run (hereinafter also simply referred to as "enthalpy of fusion ΔHm2") and the material are within the above-mentioned specific range, it is possible to obtain three-dimensionally fabricated objects with good appearance, mechanical properties, and excellent heat resistance when three-dimensionally fabricated in a powder bed fusion 3D printer. Furthermore, laser melting becomes easier. Although the mechanism is not clear at this stage, possible non-limiting mechanisms include: (1) when the enthalpy of fusion ΔHm1 is 50 J / g or less, viscosity unevenness and yellowing due to heating are further suppressed during melting, making it easier to obtain three-dimensionally fabricated objects with a good appearance, and the amount of unmelted material during laser melting is reduced, improving mechanical properties; and (2) when the enthalpy of fusion ΔHm2 is 30 J / g or more, the crystallization temperature is increased, improving heat resistance.

[0010] <Polybutylene terephthalate resin powder (I)> (Polybutylene terephthalate resin) Polybutylene terephthalate resin (PBT resin) (1) At least terephthalic acid or its ester-forming derivative (C １ - ６(1) A resin obtained by polycondensation of a dicarboxylic acid component containing alkyl esters or acid halides (such as (2) an alkylene glycol (1,4-butanediol) having at least 4 carbon atoms or an ester-forming derivative thereof (such as an acetylated compound). In one embodiment, the polybutylene terephthalate resin is not limited to homopolybutylene terephthalate resin, but may be a copolymer containing 70 mol% or more of butylene terephthalate units.

[0011] The amount of terminal carboxyl groups in the polybutylene terephthalate resin is preferably 30 meq / kg or less, but is not particularly limited as long as it does not hinder the purpose of this disclosure, more preferably 25 meq / kg or less, and even more preferably 20 meq / kg or less.

[0012] In one embodiment, the polybutylene terephthalate resin contained in the polybutylene terephthalate resin powder (I) preferably contains: a constituent unit derived from terephthalic acid, which is a dicarboxylic acid component, and a constituent unit derived from 1,4-butanediol, which is a glycol component; and one or more other constituent units selected from a constituent unit derived from a dicarboxylic acid component other than terephthalic acid, and a constituent unit derived from a glycol component other than 1,4-butanediol. By containing the above constituent units in the polybutylene terephthalate resin contained in the powder (I), melting by laser becomes easier, the enthalpies of melt ΔHm1 and ΔHm2 can be easily adjusted to a suitable range, and a three-dimensional molded product with good appearance, mechanical properties, and excellent heat resistance can be easily obtained. In this specification, "derived from" means the reaction residue after the polycondensation reaction of the monomer component.

[0013] Other dicarboxylic acid components besides terephthalic acid include aromatic dicarboxylic acids other than terephthalic acid or their ester-forming derivatives, such as isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, 4,4'-dicarboxydiphenyl ether, etc. ８ - １４ Aromatic dicarboxylic acids; such as succinic acid, adipic acid, azelaic acid, sebacic acid, etc. ４ - １６alkanedicarboxylic acids; C such as cyclohexanedicarboxylic acid ５ - １０ cycloalkanedicarboxylic acids; ester-forming derivatives of these dicarboxylic acid components (C １ - ６ alkyl ester derivatives, acid halides, etc.) can be used. These dicarboxylic acid components can be used alone or in combination of two or more.

[0014] Among these dicarboxylic acid components, from the viewpoint of easily lowering ΔHm1 of the polybutylene terephthalate resin powder (I), C such as isophthalic acid ８ - １２ aromatic dicarboxylic acids, and / or C such as adipic acid, azelaic acid, sebacic acid ６ - １２ alkanedicarboxylic acids are more preferable, and C such as isophthalic acid ８ - １２ aromatic dicarboxylic acids are even more preferable.

[0015] As glycol components other than 1,4-butanediol, for example, C such as ethylene glycol, propylene glycol, trimethylene glycol, 1,3-butylene glycol, hexamethylene glycol, neopentyl glycol, 1,3-octanediol ２ - １０ alkylene glycols; polyoxyalkylene glycols such as diethylene glycol, triethylene glycol, dipropylene glycol; alicyclic diols such as cyclohexanedimethanol, hydrogenated bisphenol A; aromatic diols such as bisphenol A, 4,4'-dihydroxybiphenyl; C of bisphenol A such as 2-mole adduct of ethylene oxide of bisphenol A, 3-mole adduct of propylene oxide of bisphenol A ２ - ４ alkylene oxide adducts; or ester-forming derivatives (acetylates, etc.) of these glycols can be used. These glycol components can be used alone or in combination of two or more.

[0016] Among these glycol components, ethylene glycol, trimethylene glycol, etc. are considered to be the most effective at lowering the ΔHm1 of polybutylene terephthalate resin powder (I). ２ - ６ Polyoxyalkylene glycols such as alkylene glycols and diethylene glycols, and / or alicyclic diols such as cyclohexanedimethanol are more preferred.

[0017] Examples of hydroxycarboxylic acids include aromatic hydroxycarboxylic acids such as 4-hydroxybenzoic acid, 3-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, and 4-carboxy-4'-hydroxybiphenyl; aliphatic hydroxycarboxylic acids such as glycolic acid and hydroxycaproic acid; C3-12 lactones such as propiolactone, butyrolactone, valerolactone, and caprolactone (ε-caprolactone, etc.); and ester-forming derivatives of these comonomer components (C １ - ６ Examples include alkyl ester derivatives, acid halides, acetylated compounds, etc.

[0018] In one embodiment, in the polybutylene terephthalate resin powder (I), it is preferable that the other constituent units in the polybutylene terephthalate resin include constituent units derived from dicarboxylic acid components other than terephthalic acid, C ８ - １２ It is more preferable to include an aromatic dicarboxylic acid, and even more preferable to include a structural unit derived from isophthalic acid. The inclusion of other structural units derived from isophthalic acid other than terephthalic acid tends to lower the enthalpy of fusion ΔHm1 of the polybutylene terephthalate resin powder (I).

[0019] In one embodiment, in the polybutylene terephthalate resin powder (I), it is preferable that the content of constituent units derived from dicarboxylic acid components other than terephthalic acid in the total amount of constituent units derived from dicarboxylic acid components is 10 mol% or more and 15 mol% or less, and / or the content of constituent units derived from glycol components other than 1,4-butanediol in the total amount of constituent units derived from glycol components is 10 mol% or more and 15 mol% or less. By having the content of constituent units derived from dicarboxylic acid components other than terephthalic acid in the total amount of constituent units derived from carboxylic acid components (100 mol%), and / or the content of constituent units derived from glycol components other than 1,4-butanediol in the total amount of constituent units derived from glycol components (100 mol%) be within the above range, the melting enthalpy ΔHm1 of the polybutylene terephthalate resin powder (I) can be controlled to a more suitable range.

[0020] The content of constituent units derived from dicarboxylic acid components other than terephthalic acid in the total amount (100 mol%) of constituent units derived from dicarboxylic acid components is preferably 10 mol% or more and 15 mol% or less, more preferably 10 mol% or more and 14 mol% or less, even more preferably 11 mol% or more and 14 mol% or less, and particularly preferably 12 mol% or more and 13 mol% or less.

[0021] The content of constituent units derived from glycol components other than 1,4-butanediol in the total amount (100 mol%) of constituent units derived from glycol components is preferably 10 mol% or more and 15 mol% or less, more preferably 10 mol% or more and 14 mol% or less, even more preferably 11 mol% or more and 14 mol% or less, and particularly preferably 12 mol% or more and 13 mol% or less.

[0022] The method for synthesizing the polybutylene terephthalate resin contained in the polybutylene terephthalate resin powder (I) is not limited, and it can be appropriately produced by conventionally known methods such as interfacial polycondensation using condensation reactions or transesterification reactions, melt polymerization, and solution polymerization. The degree of polymerization of the resin can be increased by heat treatment of the obtained resin under reduced pressure or in the presence of an inert gas to induce solid-phase polymerization, but from the viewpoint of easily balancing the enthalpy of fusion ΔHm1 and the enthalpy of fusion ΔHm2, it is preferable that the degree of polymerization of the resin is not too high.

[0023] (Weight-average molecular weight (Mw)) In one embodiment, the weight-average molecular weight (Mw) of the polybutylene terephthalate resin powder (I), that is, the weight-average molecular weight (Mw) of the polybutylene terephthalate resin, is preferably 50,000 to 100,000, more preferably 55,000 to 95,000, even more preferably 55,000 to 90,000, and particularly preferably 58,000 to 90,000. In this specification, "weight-average molecular weight (Mw)" means the value measured by gel permeation chromatography (in polystyrene equivalent). By having the weight-average molecular weight (Mw) of the polybutylene terephthalate resin within the above range, it is easier to increase ΔHm2 and intrinsic viscosity (IV) while keeping the melting enthalpy ΔHm1 low, and the resulting three-dimensional molded product is more likely to have good appearance, mechanical properties, and heat resistance. In one embodiment, the weight-average molecular weight (Mw) of the polybutylene terephthalate resin powder (I) may be 50,000 to 80,000, 53,000 to 75,000, or 55,000 to 70,000, from the viewpoint of more easily combining good appearance, mechanical properties, and heat resistance. In another embodiment, the weight-average molecular weight (Mw) of the polybutylene terephthalate resin powder (I) may be 80,000 to 100,000, 83,000 to 98,000, or 85,000 to 95,000, from the viewpoint of more easily improving mechanical properties. The weight-average molecular weight (Mw) can be adjusted, for example, by adjusting the polymerization temperature, polymerization time, etc., during the production of the polybutylene terephthalate resin.

[0024] (Intrinsic Viscosity (IV)) In one embodiment, the intrinsic viscosity (IV) of the polybutylene terephthalate resin powder (I), that is, the intrinsic viscosity (IV) of the polybutylene terephthalate resin, is preferably 1.0 dL / g or less, more preferably 0.65 dL / g or more and 1.0 dL / g or less, even more preferably 0.7 dL / g or more and 1.0 dL / g or less, and particularly preferably 0.75 dL / g or more and 1.0 dL / g or less. When the intrinsic viscosity (IV) of the polybutylene terephthalate resin is within the above range, the enthalpy of melting ΔHm1 is kept low while the enthalpy of melting ΔHm is easily increased, making it easier to combine good appearance, mechanical properties, and heat resistance. In one embodiment, the intrinsic viscosity (IV) of the polybutylene terephthalate resin may be 0.65 dL / g or more and 0.85 dL / g or less, 0.675 dL / g or more and 0.825 dL / g or less, or 0.7 dL / g or more and 0.8 dL / g or less, from the viewpoint of more easily combining good appearance, mechanical properties, and heat resistance. In another embodiment, the intrinsic viscosity (IV) of the polybutylene terephthalate resin may be 0.85 dL / g or more and 1.0 dL / g or less, 0.875 dL / g or more and 1.0 dL / g or less, or 0.9 dL / g or more and 1.0 dL / g or less, from the viewpoint of more easily improving mechanical properties. The intrinsic viscosity (IV) can also be adjusted by blending polybutylene terephthalate resins having different intrinsic viscosities (IV). For example, a polybutylene terephthalate resin with an intrinsic viscosity (IV) of 0.9 dL / g can be prepared by blending a polybutylene terephthalate resin with an intrinsic viscosity (IV) of 1.0 dL / g with a polybutylene terephthalate resin with an intrinsic viscosity (IV) of 0.7 dL / g. The intrinsic viscosity (IV) of the polybutylene terephthalate resin can be measured, for example, in o-chlorophenol at a temperature of 35°C. The intrinsic viscosity (IV) can be adjusted, for example, by adjusting the polymerization temperature, polymerization time, etc., during the production of the polybutylene terephthalate resin.

[0025] <Enthalpy of Melting ΔHm1, ΔHm2> The polybutylene terephthalate resin powder (I) according to this embodiment has an enthalpy of melting ΔHm1 of 50 J / g or less measured in the 1st Run when heated from 30°C to 260°C at a heating rate of 20°C / min, and an enthalpy of melting ΔHm2 of 30 J / g or more measured in the 2nd Run, as measured by a differential scanning calorimeter. Because the enthalpy of melting ΔHm1 measured in the 1st Run when heated from 30°C to 260°C at a heating rate of 20°C / min is 50 J / g or less, the resulting three-dimensionally fabricated object has superior mechanical properties and is more likely to have a good appearance. Furthermore, melting by laser or the like becomes easier when fabricating with a powder bed fusion 3D printer. Furthermore, if the enthalpy of fusion ΔHm2 measured in the 2nd Run is 30 J / g or higher, the resulting three-dimensional fabricated object will have superior heat resistance. Since lowering the value of the enthalpy of fusion ΔHm1 tends to lower the value of the enthalpy of fusion ΔHm2 as well, it is preferable to adjust both in a balanced manner using the method described later.

[0026] Methods for adjusting the enthalpy of fusion ΔHm1 and ΔHm2 include, for example, adjusting the type and composition ratio of the constituent units of the polybutylene terephthalate resin, the weight-average molecular weight (Mw), the intrinsic viscosity (IV), the particle size of the polybutylene terephthalate resin powder (I), or selecting whether or not to perform heat treatment. For example, if the polybutylene terephthalate resin contains other constituent units derived from copolymer components, the enthalpy of fusion ΔHm1 tends to be low, and in particular, if the comonomer units contain aromatic dicarboxylic acids, the enthalpy of fusion ΔHm1 tends to be even lower. The smaller the weight-average molecular weight (Mw) and / or intrinsic viscosity (IV) of the polybutylene terephthalate resin powder (I), the more easily the fluctuation of the enthalpy of fusion ΔHm1 is suppressed while the enthalpy of fusion ΔHm2 tends to be higher. The larger the median diameter (D50) of the polybutylene terephthalate resin powder (I), the smaller the enthalpy of fusion ΔHm1 tends to be, and the larger the enthalpy of fusion ΔHm2 tends to be. The smaller the ratio (D90 / D10) between the particle size D90 at which the volume-based cumulative frequency of the polybutylene terephthalate resin powder (I) is 90% and the particle size D10 at which the volume-based cumulative frequency is 10%, the smaller the enthalpy of fusion ΔHm1 tends to be, and the larger the enthalpy of fusion ΔHm2 tends to be. The enthalpy of fusion ΔHm1 and ΔHm2 can be adjusted by appropriately combining the above. It is preferable that these parameters be adjusted within a range that facilitates fabrication by a powder bed fusion 3D printer. Furthermore, if heat treatment is applied to the polybutylene terephthalate resin powder (I), the enthalpy of fusion ΔHm1 tends to increase. Therefore, it is preferable to either make the value of the enthalpy of fusion ΔHm1 sufficiently small before heat treatment, or to not perform heat treatment on the polybutylene terephthalate resin powder (I).

[0027] In one embodiment, the enthalpy of melting ΔHm1 measured in the 1st Run when the temperature is raised from 30°C to 260°C at a heating rate of 20°C / min, as measured by a differential scanning calorimeter, is preferably 30 to 50 J / g or less, more preferably 35 to 50 J / g or less, even more preferably 40 to 50 J / g or less, and particularly preferably 45 to 50 J / g or less. In one embodiment, the enthalpy of melting ΔHm2 measured in the 2nd Run when the temperature is raised from 30°C to 260°C at a heating rate of 20°C / min, as measured by a differential scanning calorimeter, is preferably 30 to 50 J / g, more preferably 30 to 45 J / g, even more preferably 30 to 40 J / g, and particularly preferably 30 to 35 J / g. The numerical ranges described above for the enthalpy of melting ΔHm1 and the numerical ranges described above for the enthalpy of melting ΔHm2 can be combined in any way.

[0028] In one embodiment, the ratio of the enthalpy of melting ΔHm2 to the enthalpy of melting ΔHm1 (ΔHm2 / ΔHm1) is preferably 0.65 to 0.75, more preferably 0.66 to 0.75, even more preferably 0.67 to 0.75, and particularly preferably 0.68 to 0.75. When the ratio of the enthalpy of melting ΔHm2 to the enthalpy of melting ΔHm1 (ΔHm2 / ΔHm1) is within the above range, melting by laser or the like during fabrication becomes easier, and the appearance and mechanical properties of the resulting three-dimensional fabricated object tend to be better.

[0029] (Melting point Tm2) In one embodiment, the polybutylene terephthalate resin powder (I) preferably has a melting point Tm2 measured by a differential scanning calorimeter of 190 to 220°C, more preferably 195 to 220°C, even more preferably 195 to 210°C, and particularly preferably 200 to 210°C. Having a melting point Tm2 within the above range makes melting by laser or the like during molding easier, and the appearance and mechanical properties of the resulting three-dimensional molded object tend to be better.

[0030] (Median Diameter (D50)) In one embodiment, the median diameter (D50) of the polybutylene terephthalate resin powder (I) is preferably 30 μm or more and 70 μm or less, more preferably 35 μm or more and 65 μm or less, and even more preferably 40 μm or more and 60 μm or less. When the median diameter (D50) is within the above range, a uniform thin layer can be formed when shaping with a powder sintering method 3D printer. In addition, the adhesion strength between layers is increased, and it is easy to obtain a three-dimensional shaped object with better strength and heat resistance. In this specification, the "median diameter (D50)" means the particle diameter D50 at which the cumulative frequency is 50% in the volume-based particle size distribution by the laser diffraction / scattering type particle size distribution measurement method. The median diameter (D50) can be measured using, for example, a laser diffraction / scattering type particle size distribution measuring device (for example, manufactured by Horiba, Ltd., product name: LA-960).

[0031] (Particle Diameter D90, Particle Diameter D10) In one embodiment, the ratio (D90 / D10) of the particle diameter D90 at which the cumulative frequency is 90% in the volume-based particle size distribution of the polybutylene terephthalate resin powder (I) to the particle diameter D10 at which the cumulative frequency is 10% in the volume-based particle size distribution is preferably 5 or less, more preferably 1 or more and 5 or less, even more preferably 1 or more and 4 or less, and particularly preferably 2 or more and 3 or less. The particle diameters D90 and D10 can be calculated by the same method as the above-described median diameter (D50). When the ratio (D90 / D10) of the particle diameter D90 to the particle diameter D10 is 5 or less, in three-dimensional shaping by the powder bed fusion bonding method, it is easy to form a uniform powder layer, and the generation of voids and warping in the shaped object is easily suppressed.

[0032] In one embodiment, the particle diameter D90 of the polybutylene terephthalate resin powder (I) is preferably 60 μm or more and 110 μm or less, more preferably 65 μm or more and 100 μm or less, even more preferably 70 μm or more and 95 μm or less, and particularly preferably 75 μm or more and 90 μm or less.

[0033] In one embodiment, the particle size D10 of the polybutylene terephthalate resin powder (I) is preferably 5 μm or more and 50 μm or less, more preferably 10 μm or more and 45 μm or less, even more preferably 15 μm or more and 40 μm or less, and particularly preferably 20 μm or more and 35 μm or less.

[0034] The median diameter (D50), the particle size D90, and the particle size D10 can be within the above ranges by adjusting the grinding conditions of the polybutylene terephthalate resin and the classification means including sieving and fluid classification.

[0035] The shape of the polybutylene terephthalate resin powder (I) is not particularly limited as long as it has the effects of the present disclosure, and it may be in any form such as spherical (including substantially spherical), spindle-shaped, irregular particle-shaped, fibril-shaped, fibrous, etc. From the perspective of fluidity during shaping, it is preferably spherical with a high sphericity.

[0036] The polybutylene terephthalate resin powder (I) contains the above-mentioned powdery polybutylene terephthalate resin. The polybutylene terephthalate resin formed into pellets, fibers, films, etc. can be pulverized by dry pulverization, wet pulverization, or cryogenic pulverization using a jet mill, bead mill, hammer mill, ball mill, cutter mill, pin mill, stone mortar type grinder, etc., and the polybutylene terephthalate resin powder (I) can be obtained by classification means including sieving and fluid classification.

[0037] (Heat treatment) The polybutylene terephthalate resin powder (I) may or may not be heat-treated by heating before being formed by a 3D printer. Examples of the heat treatment include pulverizing while heating during the above-mentioned pulverization treatment, and being subjected to solid-phase polymerization.

[0038] In one embodiment, it is preferable that the polybutylene terephthalate resin powder (I) has not been subjected to heat treatment by heating during the pulverization of pellets, etc., and / or between being mixed with the powder material (X) and being used in the 3D printer. By not being subjected to heat treatment by heating until being used in the 3D printer, changes in the enthalpy of fusion are less likely to occur, and it is easier to adjust the enthalpies of fusion ΔHm1 and ΔHm2. In addition, softening of the resin and a decrease in elastic modulus are less likely to occur, and the moldability, appearance, and mechanical properties of the three-dimensional object are more easily improved. In one embodiment, it is preferable that the polybutylene terephthalate resin powder (I) has not been subjected to heat treatment at a temperature of 180°C or higher before being mixed with the powder material (X) and being used in the 3D printer, and more preferably, has not been subjected to heat treatment at a temperature of 180°C or higher for 20 hours or more. In one embodiment, the polybutylene terephthalate resin powder (I) may be pulverized at room temperature or ambient temperature (for example, 20 to 35°C).

[0039] <Powdered Material (X)> The powdered material (X) contains polybutylene terephthalate resin powder (I). In one embodiment, the content of polybutylene terephthalate resin powder (I) in the powdered material (X) is preferably 50% by mass or more, more preferably 75% by mass or more, even more preferably 90% by mass or more, and particularly preferably 99% by mass or more, based on the total mass of the powdered material (X). The upper limit is not particularly limited, but may be 100% by mass or 99% by mass or less. That is, the proportion of powder (I) in the powdered material (X) may be 50 to 100% by mass, 50 to 99% by mass, 75 to 100% by mass, or 70 to 99% by mass, based on the total mass of the powdered material (X).

[0040] (Angle of Repose) In one embodiment, the powder material (X) preferably has an angle of repose of 42° or less, more preferably 41° or less, even more preferably 40° or less, and particularly preferably 39° or less. When the angle of repose is within the above range, the powder material (X) has superior fluidity, making it easier to obtain three-dimensional molded objects with better appearance and mechanical properties. The angle of repose can be measured by the method described in the examples below.

[0041] (Other Additives) The powder material (X) may contain additives other than the polybutylene terephthalate resin powder (I). Examples of additives other than the powder (I) (hereinafter referred to as "other additives") include various fibrous, granular, and plate-shaped inorganic and organic fillers, and powders of thermoplastic resins other than polybutylene terephthalate resin (other thermoplastic resins).

[0042] (Fillers) Examples of fillers include granular fillers with an average particle size of 500 nm or less, preferably 400 nm or less, plate-shaped fillers, and fibrous fillers with an average fiber length of 100 μm or less. Including such fillers makes it easier to improve the powder flowability and dispersibility of the polybutylene terephthalate resin powder (I). It also makes it easier to improve the strength of the resulting three-dimensional molded object. In one embodiment, it is preferable to include granular fillers from the viewpoint of further improving powder flowability. In this specification, "average particle size" means the arithmetic mean particle diameter based on volume measured by laser diffraction / scattering particle size distribution analysis. The average particle size can be measured, for example, using a laser diffraction / scattering particle size distribution analyzer (e.g., Horiba, Ltd., product name: LA-960). The average fiber length can be measured, for example, using an image measuring instrument (e.g., Nicole Co., Ltd., product name: LUZEXFS) to measure the fiber length of the fibrous filler and calculated as the average value.

[0043] Examples of granular fillers include carbon black, graphite, silica, quartz powder, glass beads, glass balloons, glass powder, calcium silicate, aluminum silicate, kaolin, clay, diatomaceous earth, silicates such as wollastonite, metal oxides such as iron oxide, titanium oxide, zinc oxide, antimony trioxide, and alumina, metal carbonates such as calcium carbonate and magnesium carbonate, metal sulfates such as calcium sulfate and barium sulfate, and other materials such as ferrite, silicon carbide, silicon nitride, boron nitride, and various metal powders. These granular fillers may be used individually or in combination of two or more. From the viewpoint of powder fluidity, carbon black and silica are preferred as granular fillers. Furthermore, the granular fillers may be surface-treated with a surface treatment agent. Examples of surface treatment agents include silanol, dimethyldichlorosilane (dimethylsilyl), hexamethyldisilazane (trimethylsilyl), octylsilane (octylsilyl), and silicone oil (dimethylpolysiloxane).

[0044] Examples of fibrous fillers include glass fibers, milled glass fibers, carbon fibers, carbon nanotubes, asbestos fibers, silica fibers, silica-alumina fibers, alumina fibers, zirconia fibers, boron nitride fibers, silicon nitride fibers, boron fibers, silicate fibers such as potassium titanate and wollastonite, magnesium sulfate fibers, aluminum borate fibers, and inorganic fibrous materials such as stainless steel, aluminum, titanium, copper, and brass. High-melting-point organic fibrous materials such as polyamide, fluororesin, polyester resin, and acrylic resin can also be used. These fibrous fillers may be used individually or in combination of two or more. From the viewpoint of powder fluidity, carbon nanotubes are preferred as the fibrous filler. The fibrous filler may also be surface-treated with a surface treatment agent. Examples of surface treatment agents include silanol, dimethyldichlorosilane (dimethylsilyl), hexamethyldisilazane (trimethylsilyl), octylsilane (octylsilyl), and silicone oil (dimethylpolysiloxane).

[0045] Examples of plate-shaped fillers include mica, glass flakes, talc, and various metal foils. These plate-shaped fillers may be used individually or in combination of two or more types.

[0046] In one embodiment, the powder material (X) preferably further contains fumed inorganic oxide particles (II). The inclusion of fumed inorganic oxide particles (II) improves the fluidity of the powder material (X) and the anti-caking effect of the powders during three-dimensional molding using a powder bed fusion 3D printer, improves the antistatic effect of the powder material (X), and makes it easier to obtain three-dimensional molded objects with better appearance and mechanical properties.

[0047] If the powder material (X) contains a filler, its content can be 0 to 100 parts by mass, 0 to 89 parts by mass, or 0 to 75 parts by mass per 100 parts by mass of polybutylene terephthalate resin powder (I).

[0048] (Other Thermoplastic Resins) The powder material (X) may contain powders of other thermoplastic resins other than polybutylene terephthalate resin powder (I). Examples of other thermoplastic resins include polyethylene resin, polypropylene resin, polyethylene terephthalate resin, and polyamide resin. These may be used individually or in combination of two or more. It is preferable that the other thermoplastic resins are blended into the powder material (X) as powders. When the powder material (X) contains powders of other thermoplastic resins, the amount blended can be 0 to 50 parts by mass, 0 to 20 parts by mass, or 0 to 5 parts by mass per 100 parts by mass of polybutylene terephthalate resin powder (I).

[0049] <Method for manufacturing powder material (X) for 3D printers> Powder material (X) can be manufactured by mixing polybutylene terephthalate resin powder (I) with other additives as needed using conventionally known methods. For example, mixing methods such as shaking, mixing methods involving grinding such as ball mills, and mixing methods using stirring blades such as Henschel mixers can be used.

[0050] [Three-Dimensional Fabricated Object] The three-dimensional fabricated object according to this embodiment is formed using a powder material (X) containing the polybutylene terephthalate resin powder (I) described above. That is, the three-dimensional fabricated object according to this embodiment includes a sintered body of the powder material (X). Such a three-dimensional fabricated object has a good appearance and mechanical properties, and furthermore, possesses excellent heat resistance.

[0051] <Method for Manufacturing a Three-Dimensional Object> The method for manufacturing a three-dimensional object according to this embodiment includes the step of supplying a powder material (X) containing polybutylene terephthalate resin powder (I) to a powder bed fusion 3D printer. Thereafter, a three-dimensional object is fabricated using the supplied powder material (X) (fabrication step).

[0052] (Manufacturing Process) In the manufacturing process using a powder bed fusion 3D printer, a three-dimensional object is manufactured by selectively irradiating a powder surface (X) with laser light or an electron beam, melting and solidifying the powder material (X) while layering it. The powder material (X) according to this embodiment contains the aforementioned characteristic polybutylene terephthalate resin powder (I), and is easily melted by irradiation with laser light or an electron beam, making it easy to obtain three-dimensional objects with good appearance and mechanical properties, and the three-dimensional objects have excellent heat resistance. Conventional powder sintering 3D printers can be used, for example, the AM-E 3D printer manufactured by Aspect Co., Ltd. ３ "II 300C-HT" and other similar products can be used.

[0053] Another embodiment of the present disclosure is the use of the powder material (X) containing the polybutylene terephthalate resin powder (I) described above as a resin raw material for three-dimensional objects manufactured using a 3D printer, or a method of using it.

[0054] A non-limiting list of exemplary embodiments and combinations of exemplary embodiments of the present disclosure is disclosed below: [1] A powder material (X) for a 3D printer comprising polybutylene terephthalate resin powder (I), wherein the enthalpy of melting ΔHm1 of the polybutylene terephthalate resin powder (I), measured by a differential scanning calorimeter, is 50 J / g or less when heated from 30°C to 260°C at a heating rate of 20°C / min, and the enthalpy of melting ΔHm2, measured in a second run, is 30 J / g or more. [2] The powder material (X) according to [1], wherein the ratio of ΔHm2 to ΔHm1 (ΔHm2 / ΔHm1) is 0.65 to 0.75. [3] The powder material (X) according to [1] or [2], wherein the polybutylene terephthalate resin contained in the polybutylene terephthalate resin powder (I) comprises a constituent unit derived from terephthalic acid, which is a dicarboxylic acid component, and a constituent unit derived from 1,4-butanediol, which is a glycol component, and one or more other constituent units selected from a constituent unit derived from a dicarboxylic acid component other than terephthalic acid and a constituent unit derived from a glycol component other than 1,4-butanediol. [4] The powder material (X) according to [3], wherein the content of constituent units derived from a dicarboxylic acid component other than terephthalic acid in the total amount of constituent units derived from a dicarboxylic acid component is 10 mol% or more and 15 mol% or less, and / or the content of constituent units derived from a glycol component other than 1,4-butanediol in the total amount of constituent units derived from a glycol component is 10 mol% or more and 15 mol% or less. [5] The powder material (X) according to [3] or [4], wherein the other constituent units include a constituent unit derived from isophthalic acid. [6] The powder material (X) according to any one of [1] to [5], wherein the median diameter (D50) of the polybutylene terephthalate resin powder (I) is 30 μm or more and 70 μm or less. [7] The powder material (X) according to any one of [1] to [6], wherein the ratio (D90 / D10) of the polybutylene terephthalate resin powder (I) between the particle size D90 at which the volume-based cumulative frequency is 90% and the particle size D10 at which the volume-based cumulative frequency is 10% is 5 or less.[8] The powder material (X) according to any one of [1] to [7], wherein the intrinsic viscosity (IV) of the polybutylene terephthalate resin powder (I) is 1.0 dL / g or less. [9] The powder material (X) according to any one of [1] to [8] further comprises fumed inorganic oxide particles (II).

[10] The powder material (X) according to any one of [1] to [9], wherein the angle of repose is 42° or less.

[11] A three-dimensional molded object comprising a sintered body of the powder material (X) according to any one of [1] to

[10] . Each configuration in each embodiment and their combinations are examples, and additions, omissions, substitutions, and other modifications of the configuration can be made as appropriate without departing from the spirit of the present disclosure. The present disclosure is not limited by embodiments.

[0055] The present disclosure will be further illustrated by the following examples, but these examples will not limit the interpretation of the present disclosure.

[0056] The polybutylene terephthalate resins used in the examples and comparative examples were prepared as follows: (Polybutylene terephthalate resin) ・PBT1 100 parts by mass of dimethyl terephthalate, 14.3 parts by mass of dimethyl isophthalate, 77.4 parts by mass of 1,4-butanediol, and 0.1 parts by mass of titanium tetrabutoxy were charged into a reactor equipped with a stirrer and a distillation column, and after purging with nitrogen, the temperature of the reaction system was raised to 160°C and stirring was started. Furthermore, the temperature was gradually increased and the by-product methanol was removed by distillation. When the distilled methanol exceeded 90% by mass of the theoretical amount, the temperature was raised to 210°C, and then it was transferred to another reactor (polycondensation reactor), and the pressure was reduced to 0.1 Torr over 1 hour, while the temperature was simultaneously raised to 240°C. After stirring continued for 3 hours at a pressure of 0.1 Torr, the molten material was discharged from the reactor as strands and pelletized to obtain polybutylene terephthalate resin pellets. The weight-average molecular weight (Mw) of the obtained polybutylene terephthalate resin was 59,000, and the intrinsic viscosity (IV) was 0.76 dL / g (the measurement method is described below). ・PBT2 100 parts by mass of dimethyl terephthalate, 14.3 parts by mass of dimethyl isophthalate, 77.4 parts by mass of 1,4-butanediol, and 0.1 parts by mass of titanium tetrabutoxy were charged into a reactor equipped with a stirrer and a distillation column. After purging with nitrogen, the temperature of the reaction system was raised to 160°C and stirring was started. Furthermore, the temperature was gradually increased to remove the by-product methanol. When the distilled methanol exceeded 90% by mass of the theoretical amount, the temperature was raised to 210°C, and then it was transferred to another reactor (polycondensation reactor), where the pressure was reduced to 0.1 Torr over 1 hour, and the temperature was simultaneously raised to 240°C. After stirring for 3 hours at a pressure of 0.1 Torr, the molten material was discharged from the reactor as strands and pelletized to obtain polybutylene terephthalate resin pellets. Next, these pellets were supplied to a solid-phase reactor with a heating jacket (passing through a heat transfer medium at 185°C), and solid-phase polymerization was carried out at 181-182°C for 4 hours. The weight-average molecular weight (Mw) of the obtained polybutylene terephthalate resin was 88,000, and the intrinsic viscosity (IV) was 0.95 dL / g (measurement method is described below).100 parts by mass of dimethyl terephthalate, 6.4 parts by mass of dimethyl isophthalate, 72.1 parts by mass of 1,4-butanediol, and 0.1 parts by mass of titanium tetrabutoxy were charged into a reactor equipped with a stirrer and a distillation column. After purging with nitrogen, the temperature of the reaction system was raised to 160 °C and stirring was started. The temperature was then gradually increased to remove the by-product methanol. When the amount of distilled methanol exceeded 90% by mass of the theoretical amount, the temperature was raised to 210 °C, and then transferred to another reactor (polycondensation reactor). The pressure was reduced to 0.1 Torr over 1 hour, and the temperature was simultaneously raised to 240 °C. After stirring continued at a pressure of 0.1 Torr for 3 hours, the molten material was discharged from the reactor as strands and pelletized to obtain polybutylene terephthalate resin pellets. The weight-average molecular weight (Mw) of the obtained polybutylene terephthalate resin was 59,000, and the intrinsic viscosity (IV) was 0.76 dL / g (the measurement method is described below). ・PBT4 100 parts by mass of dimethyl terephthalate, 25 parts by mass of dimethyl isophthalate, 84.8 parts by mass of 1,4-butanediol, and 0.1 parts by mass of titanium tetrabutoxy were charged into a reactor equipped with a stirrer and a distillation column. After purging with nitrogen, the temperature of the reaction system was raised to 160°C and stirring was started. Furthermore, the temperature was gradually increased to remove the by-product methanol. When the distilled methanol exceeded 90% by mass of the theoretical amount, the temperature was raised to 210°C, and then it was transferred to another reactor (polycondensation reactor), where the pressure was reduced to 0.1 Torr over 1 hour, and the temperature was simultaneously raised to 240°C. After stirring for 3 hours at a pressure of 0.1 Torr, the molten material was discharged from the reactor as strands and pelletized to obtain polybutylene terephthalate resin pellets. The weight-average molecular weight (Mw) of the obtained polybutylene terephthalate resin was 59,000 and the intrinsic viscosity (IV) was 0.76 dL / g (the measurement method is described below). ・PBT5 100 parts by mass of dimethyl terephthalate, 67.8 parts by mass of 1,4-butanediol, and 0.1 parts by mass of titanium tetrabutoxy were charged into a reactor equipped with a stirrer and a distillation column. After purging with nitrogen, the temperature of the reaction system was raised to 160°C and stirring was started. Furthermore, the temperature was gradually increased and methanol, a by-product, was removed by distillation.When the amount of distilled methanol exceeded 90% by mass of the theoretical amount, the temperature was raised to 210°C. This was then transferred to another reactor (polycondensation reactor), where the pressure was reduced to 0.1 Torr over 1 hour, while the temperature was simultaneously raised to 240°C. After stirring at a pressure of 0.1 Torr for 3 hours, the molten material was discharged from the reactor as strands and pelletized to obtain polybutylene terephthalate resin pellets. The obtained polybutylene terephthalate resin had a weight-average molecular weight (Mw) of 60,000 and an intrinsic viscosity (IV) of 0.77 dL / g (measurement methods are described below).

[0057] The weight-average molecular weight (Mw) and intrinsic viscosity (IV) of the polybutylene terephthalate resin were measured as follows: <Weight-average molecular weight (Mw)> For each polybutylene terephthalate resin pellet in the examples and comparative examples, the weight-average molecular weight (Mw) was measured by gel permeation chromatography according to the following measurement conditions: ・Apparatus: Malvern Viscotek TDA302 detector + Pump autosampler apparatus ・Detector: RI ・Solvent: Toluene ・Column: Tosoh TSKgel GMHHR-M (300 mm × 7.8 mmφ) ・Flow rate: 1 mL / min ・Temperature: 75°C ・Sample concentration: 2.5 mg / mL ・Injection volume: 100 μL ・Standard sample: Monodisperse polystyrene

[0058] <Intrinsic Viscosity (IV)> The intrinsic viscosity (IV) of each polybutylene terephthalate resin pellet from the Examples and Comparative Examples was determined as follows: Each polybutylene terephthalate resin pellet from the Examples and Comparative Examples was dissolved in 100 ml of orthochlorophenol (solution concentration C = 1.2 g / dl), and the viscosity of the solution at 25°C was measured using an Ostwald viscometer. The viscosity of the solvent was also measured in the same manner. Using the obtained solution viscosity and solvent viscosity, [η] (dl / g) was calculated using the following formula, and the obtained value was taken as the intrinsic viscosity (IV): ηsp / C = [η] + K[η] ２ • C (wherein ηsp = (solution viscosity (dl / g) / solvent viscosity (dl / g)) - 1, and K is Huggins constant (assuming 0.343)).

[0059] [Examples 1, 2, Comparative Examples 1-4] (Production of Polybutylene Terephthalate Resin Powder (I)) Each of the polybutylene terephthalate resins from PBT1 to PBT5 was pulverized using a jet mill ("New Microcyclomat MCM-3", manufactured by Masuno Seisakusho Co., Ltd.) and sieved using a sieve ("JTS-200-25-44", manufactured by Tokyo Screen Co., Ltd.) to obtain polybutylene terephthalate resin powder (I). In addition, only the polybutylene terephthalate resin (PBT1) of Comparative Example 3 was heat-treated at 180°C for 3 hours under a nitrogen atmosphere after pulverization.

[0060] The melting point Tm2, ​​enthalpy of fusion ΔHm1, ΔHm2, median diameter (D50), particle size D90, and particle size D10 of the obtained polybutylene terephthalate resin powder (I) were measured using the following method. The results are shown in Table 1.

[0061] (Melting point Tm2 and enthalpy of fusion ΔHm1, ΔHm2) For each polybutylene terephthalate resin powder (I) in the examples and comparative examples, the melting point Tm2 and enthalpy of fusion ΔHm1, ΔHm2 were measured using a differential scanning calorimeter (Parkin Elmer, product name: DSC8000). 5 mg of each sample was heated in a nitrogen atmosphere from 30°C to 260°C at a heating rate of 20°C / min (1st RUN), held at 260°C for 10 minutes, cooled to 30°C at a cooling rate of 20°C / min, and then heated from 30°C to 260°C at a heating rate of 20°C / min (2nd RUN). The area values ​​of the endothermic peaks observed in the 1st RUN and 2nd RUN, respectively, were defined as the enthalpy of fusion ΔHm1, ΔHm2. The temperature at the peak top of the endothermic peak in the second run was defined as the melting point Tm2.

[0062] (Median diameter (D50), particle size D90, and particle size D10) For each polybutylene terephthalate resin powder (I) in the examples and comparative examples, the median diameter (D50), particle size D90, and particle size D10 were measured using a laser diffraction / scattering particle size distribution analyzer (manufactured by Horiba, Ltd., product name: LA-960) with acetone as the dispersion solvent.

[0063] (Preparation of powder material (X)) Powder material (X) was prepared by blending each of the polybutylene terephthalate resin powders (I) of the examples and comparative examples with fumed inorganic oxide particles (II) (fumed silica manufactured by Evonik Industries, product name: AEROSIL® R972, dimethyldichlorosilane surface treatment, average particle size 16 nm) in the amounts shown in Table 1.

[0064] (Angle of Repose of Powder Material (X)) The angle of repose was measured for each powder material (X) in the examples and comparative examples as follows. For each powder material (X), under conditions of 25°C and 60% humidity, 200 mL of powder material (X) was poured into a funnel with an opening diameter of 56 mm and a hole diameter of 12 mm from a height of 1 cm from the top edge of the funnel, and was allowed to fall without vibration onto a circular platform with a diameter of 12.2 cm located 7.5 cm from the bottom of the funnel. The height of the fallen conical deposit was measured, and the angle between the horizontal plane and the generatrix was calculated and defined as the angle of repose (unit: degrees). In the case of a 3D printer using the powder bed fusion method, the recoater usually operates constantly on the powder surface to continuously supply the powder material, so if the fluidity of the powder material is low, it will cause a deterioration in moldability. A smaller angle of repose indicates better powder fluidity.

[0065] Each powder material (X) in the examples and comparative examples was processed using a powder sintering 3D printer (Aspect Co., Ltd., "Raphael II 300-HT", laser type: CO2). ２ The material was supplied to a laser (10.6 μm, output: 12 W) and two three-dimensional objects were fabricated: a 150 mm × 10 mm × 4 mm test piece (test piece A) and an 80 mm × 10 mm × 4 mm test piece (test piece B).

[0066] <Visual Evaluation of Three-Dimensional Printed Objects> The visual appearance of each test piece A in the examples and comparative examples was evaluated according to the following evaluation criteria. (Evaluation Criteria) 1: The surface of the printed object was smooth, and no warping, voids, or color changes were observed visually. 3: Warping and voids were observed visually.

[0067] <Tensile Strength> For each test specimen A in the examples and comparative examples, the tensile strength in the direction parallel to the fabricated surface of test specimen A was measured in accordance with ISO 527-1 and evaluated according to the following evaluation criteria. (Evaluation Criteria) 1: Tensile strength of 40 MPa or more 3: Tensile strength less than 40 MPa

[0068] <Load Deflection Temperature> For each test specimen B of the examples and comparative examples, the load deflection temperature was measured in accordance with ASTM D648 and evaluated according to the following evaluation criteria. A bending stress of 1.8 MPa was used. (Evaluation Criteria) 1: Load deflection temperature of 65°C or higher 2: Load deflection temperature of 55°C or higher and less than 65°C 3: Load deflection temperature less than 55°C or higher The results of each evaluation are shown in Table 1.

[0069]

[0070] As shown in Table 1, the three-dimensional objects produced using the powder material (X) of the example received an "Excellent" rating in both appearance evaluation and tensile strength evaluation, and furthermore, the load deflection temperature evaluation was "1" or "2". In other words, the three-dimensional objects produced using the powder material (X) of the example had good appearance and mechanical properties, and also possessed excellent heat resistance. On the other hand, the three-dimensional objects produced using the powder material of the comparative example had at least one of the appearance, mechanical properties, and heat resistance ratings at "3", and did not possess all of the above properties. As described above, it was confirmed that the 3D printer powder material (X) of this embodiment can produce three-dimensional objects with good appearance, mechanical properties, and also excellent heat resistance.

[0071] The powder material (X) for 3D printers in this embodiment has good appearance, mechanical properties, and excellent heat resistance, making it suitable for use as a powder material for 3D printers and giving it industrial applicability. The three-dimensional molded product of this embodiment has good appearance, mechanical properties, and heat resistance, making it suitable for use in various components and giving it industrial applicability.

Claims

A powder material (X) for 3D printers containing polybutylene terephthalate resin powder (I), Powder material (X) of the polybutylene terephthalate resin powder (I), wherein the enthalpy of fusion ΔHm1 measured in the 1st Run when heated from 30°C to 260°C at a heating rate of 20°C / min is 50 J / g or less, and the enthalpy of fusion ΔHm2 measured in the 2nd Run is 30 J / g or more, as measured by a differential scanning calorimeter. 　 The powder material (X) according to claim 1, wherein the ratio of ΔHm2 to ΔHm1 (ΔHm2 / ΔHm1) is 0.65 to 0.

75. The powder material (X) according to claim 1 or 2, wherein the polybutylene terephthalate resin contained in the polybutylene terephthalate resin powder (I) comprises a constituent unit derived from terephthalic acid, which is a dicarboxylic acid component, and a constituent unit derived from 1,4-butanediol, which is a glycol component, and one or more other constituent units selected from a constituent unit derived from a dicarboxylic acid component other than terephthalic acid, and a constituent unit derived from a glycol component other than 1,4-butanediol. 　 The powder material (X) according to claim 3, wherein the content of constituent units derived from dicarboxylic acid components other than terephthalic acid in the total amount of constituent units derived from dicarboxylic acid components is 10 mol% or more and 15 mol% or less, and / or the content of constituent units derived from glycol components other than 1,4-butanediol in the total amount of constituent units derived from glycol components is 10 mol% or more and 15 mol% or less. 　 The powder material (X) according to claim 3, wherein the other constituent units include constituent units derived from isophthalic acid. 　 The powder material (X) according to claim 1 or 2, wherein the median diameter (D50) of the polybutylene terephthalate resin powder (I) is 30 μm or more and 70 μm or less. 　 The powder material (X) according to claim 1 or 2, wherein the ratio (D90 / D10) of the polybutylene terephthalate resin powder (I) between particle size D90, which has a volume-based cumulative frequency of 90%, and particle size D10, which has a volume-based cumulative frequency of 10%, is 5 or less. 　 The powder material (X) according to claim 1 or 2, wherein the intrinsic viscosity (IV) of the polybutylene terephthalate resin powder (I) is 1.0 dL / g or less. 　 Furthermore, the powder material (X) according to claim 1 or 2 further comprises fumed inorganic oxide particles (II). 　 The powder material (X) according to claim 1 or 2, wherein the angle of repose is 42° or less. 　 A three-dimensional object comprising a sintered body of the powder material (X) according to claim 1 or 2.

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