Powder composition for three-dimensional shaped article, method for producing thermoplastic resin particles, three-dimensional shaped article, and method for producing same

Abstract

Provided is a powder composition for a three-dimensional shaped article including thermoplastic resin particles (A), wherein: a thermoplastic resin composition constituting the thermoplastic resin particles (A) is obtained by blending 1-40 parts by weight of an elastomer (a2) with respect to 100 parts by weight of a polyarylene sulfide resin (a1); and the powder composition has a D50 particle size of 10-150 μm and has a cooling crystallization temperature of 150-220°C. By using, for three-dimensional shaping, a polyarylene sulfide powder composition containing an elastomer and having a low cooling crystallization temperature, it is possible to provide a warpage-free polyarylene sulfide shaped article having high elongation at break and high impact strength.

Description

Powder composition for three-dimensional shaped objects, method for producing thermoplastic resin particles, three-dimensional shaped objects, and method for producing the same

[0001] The present invention relates to a powder composition suitably used for manufacturing a three-dimensional shaped object by a powder bed fusion bonding method, a method for producing thermoplastic resin particles, a three-dimensional shaped object, and a method for producing the same. In particular, it relates to providing a three-dimensional shaped object having polyarylene sulfide as a matrix and high elongation at break and impact resistance.

[0002] As a technique for manufacturing a three-dimensional shaped object (hereinafter sometimes simply referred to as a shaped object), a powder bed fusion bonding method is known. A shaped object by the powder bed fusion bonding method is manufactured by sequentially repeating a thin layer forming step of forming a thin layer of powder and a cross-sectional shape forming step of selectively melting the formed thin layer to bond resin powder particles and form the cross-sectional shape of the shaped object. Here, as a method for selectively melting the powder, in addition to the selective laser sintering method in which a laser is selectively irradiated to a position corresponding to the cross-section of the object to be shaped after providing a layer of powder, a multi-jet fusion method in which an electromagnetic radiation absorber is printed at a position corresponding to the cross-section of the object to be shaped or an electromagnetic radiation inhibitor is printed on the non-sintered surface and then a laser or other energy rays are irradiated.

[0003] Conventional material powders for the powder bed fusion bonding method have been limited to thermoplastic resins with low melting points such as polyamide 11 and polyamide 12. Therefore, the application of three-dimensional shaped objects produced by the powder bed fusion bonding method has been limited to applications that do not require strength or heat resistance, such as shape confirmation during prototyping or trial production, and it has been difficult to expand to mounting members. However, in recent years, the range of material powders has expanded, and super engineering plastics with high strength and heat resistance, such as polyarylene sulfide and polyether ketone ketone, can also be used in the powder bed fusion bonding method. Three-dimensional shaped objects are no longer limited to shape confirmation applications and have begun to be applied to performance testing applications and final parts.

[0004] Polyarylene sulfide is a resin with excellent rigidity, heat resistance, chemical resistance, and electrical properties. Therefore, polyarylene sulfide three-dimensional molded objects are used in various electrical, electronic, mechanical, and automotive parts applications. On the other hand, its elongation at break and impact strength are inferior to those of polyamide, and in applications requiring high toughness, resins with lower heat resistance, such as polyamide 11 and polyamide 12, are still necessary.

[0005] To address these challenges, Patent Document 1 discloses a modified polyarylene sulfide powder. Patent Document 2 discloses the addition of an impact modifier to polyarylene sulfide.

[0006] Japanese Patent Publication No. 2022-530398, Japanese Patent Publication No. 2023-507413

[0007] However, the technology described in Patent Document 1 modifies the polyarylene sulfide, raising concerns that the inherent strength and other properties of the polyarylene sulfide may be compromised. The technology described in Patent Document 2 describes a polyarylene sulfide powder with a high crystallization temperature, raising concerns about its handling, such as the occurrence of warping when manufacturing long molded objects.

[0008] Therefore, the present invention aims to provide polyarylene sulfide three-dimensional molded objects that have high fracture elongation, impact strength, and no warping, in order to further expand the applications of polyarylene sulfide three-dimensional molded objects.

[0009]

[0010] To solve the above problems, the present invention has the following configuration: (1) A powder composition for three-dimensional molded objects comprising thermoplastic resin particles (A), wherein the thermoplastic resin composition constituting the thermoplastic resin particles (A) is a thermoplastic resin composition obtained by blending (a2) elastomer in an amount of 1 to 40 parts by weight with (a1) polyarylene sulfide resin, wherein the D50 particle diameter of the powder composition is 10 μm to 150 μm and the cooling crystallization temperature of the powder composition is 150°C to 220°C. (2) The powder composition according to (1), characterized in that the (a2) elastomer has a reactive functional group. (3) The powder composition according to (1) or (2), characterized in that the glass transition temperature (Tg) of the (a2) elastomer is 0°C or lower. (4) The powder composition according to any one of (1) to (3), characterized in that the (a2) elastomer is at least one selected from the group consisting of olefin-based elastomers and silicone-based elastomers. (5) The powder composition according to any one of (1) to (4), characterized in that, in the morphology observed by electron microscopy, the (a1) polyarylene sulfide resin is the matrix resin, the (a2) elastomer forms an island phase, and the number-average dispersion particle diameter of the island phase is 10 μm or less. (6) The powder composition according to any one of (1) to (5), characterized in that the D90 / D10 in the particle size distribution of the powder composition is 2 or more and 10 or less. (7) The powder composition according to any one of (1) to (6), wherein the powder composition comprises thermoplastic resin particles (A) and resin particles (B) composed of a resin composition different from the thermoplastic resin composition constituting the thermoplastic resin particles (A), wherein the resin composition constituting the resin particles (B) comprises at least one selected from the group consisting of (a1) polyarylene sulfide resin and (b) polyarylene sulfide resin different from (a1) polyarylene sulfide resin, and the cooling crystallization temperature of the resin particles (B) is 150°C or higher and 220°C or lower.(8) The powder composition according to any one of (1) to (7), characterized in that the total amount of thermoplastic resin particles (A) and resin particles (B) is 100 parts by weight, and the content of thermoplastic resin particles (A) is 1 part by weight or more and 100 parts by weight or less. (9) The powder composition according to any one of (1) to (8), characterized in that the cooling crystallization temperature of the thermoplastic resin particles (A) is 150°C or more and 220°C or less. (10) The powder composition according to any one of (1) to (9), characterized in that the total amount of thermoplastic resin particles (A) and resin particles (B) composed of a resin composition different from the thermoplastic resin composition constituting the thermoplastic resin particles (A) is 100 parts by weight, and the inorganic reinforcing material (C) is 10 parts by weight or more and 100 parts by weight or less. (11) The powder composition according to any one of (1) to (10), wherein the powder composition contains 0.1 to 10 parts by weight of inorganic fine particles (D) with a D50 particle size of 20 nm to 500 nm, with a total of 100 parts by weight of thermoplastic resin particles (A) and resin particles (B) composed of a resin composition different from the thermoplastic resin composition constituting the thermoplastic resin particles (A). (12) The powder composition according to any one of (1) to (11), wherein when a dumbbell test piece is prepared by a powder bed fusion bonding method in accordance with ISO 527-2 (2012) such that the longitudinal direction is parallel to the direction in which the recoater moves (X direction), the tensile elongation at break of the test piece in the X direction measured according to ISO 527-2 (2012) is 1.5% or more. (13) Using a powder bed fusion bonding method, a dumbbell test specimen was prepared in accordance with ISO 527-2 (2012) such that its longitudinal direction was parallel to the direction (X direction) in which the recoater moved, and the Charpy impact strength (without notches) of a test specimen cut from the parallel section obtained from the dumbbell test specimen was measured in accordance with ISO 179 (2010) and was 3.5 kJ / m. ２The powder composition described in any of (1) to (12). (14) A method for producing thermoplastic resin particles (A) comprising the following steps (1) to (3): (1) A step of melt-kneading 1 to 40 parts by weight of (a2) elastomer with 100 parts by weight of (a1) polyarylene sulfide resin and then pelletizing the mixture. (2) A step of grinding the pellets obtained in step (1). (3) A step of passing the particles ground in step (2) through a filter with a mesh size of 45 μm to 250 μm. (15) A method for producing a three-dimensional object, comprising supplying the powder composition described in any of (1) to (13) to a powder bed fusion bonding type three-dimensional object manufacturing apparatus. (16) A three-dimensional object characterized in that, in the morphology observed by an electron microscope, the thermoplastic resin composition constituting the three-dimensional object has (a1) a polyarylene sulfide resin as the matrix resin and (a2) an elastomer forming an island phase, and the number-average dispersion particle diameter of the island phase is 10 μm or less. (17) The three-dimensional object according to (16) obtained by a powder bed fusion bonding method using the powder composition according to any one of (1) to (13).

[0011] According to the present invention, by using a polyarylene sulfide powder composition with a low cooling crystallization temperature and containing an elastomer in three-dimensional fabrication, it is possible to provide polyarylene sulfide fabricated products with high fracture elongation, impact strength, and no warping.

[0012] This is a schematic diagram showing an example of a manufacturing apparatus for three-dimensional molded objects according to the present invention. This is a transmission electron microscope image of a cross-section of thermoplastic resin particles (A)-1 obtained in Manufacturing Example 1. This is a transmission electron microscope image of a cross-section of a three-dimensional molded object obtained in Example 2.

[0013] The present invention will now be described in detail along with its embodiments. The present invention is a powder composition for three-dimensional molded objects comprising thermoplastic resin particles (A), wherein the thermoplastic resin composition constituting the thermoplastic resin particles (A) is a thermoplastic resin composition comprising (a1) 100 parts by weight of polyarylene sulfide resin and (a2) elastomer in a ratio of 1 part by weight to 40 parts by weight, wherein the D50 particle diameter of the powder composition is 10 μm to 150 μm and the cooling crystallization temperature of the powder composition is 150°C to 220°C.

[0014] [(a1) Polyarylene sulfide resin] The (a1) polyarylene sulfide resin of the present invention is a resin whose main constituent unit is a repeating unit of the formula -(Ar-S)-.

[0015] Ar is a group containing an aromatic ring in which the bond exists on the aromatic ring. Examples include divalent repeating units represented by formulas (A) to (K) below, but the repeating unit represented by formula (A) is particularly preferred.

[0016]

[0017] However, R1 and R2 in the above formula are substituents selected from hydrogen, C1-C6 alkyl groups, C1-C6 alkoxy groups, and halogen groups, and R1 and R2 may be the same or different.

[0018] Furthermore, the polyarylene sulfide resin in the present invention may be any of the following: a random copolymer containing the above repeating units, a block copolymer, or a mixture thereof.

[0019] Representative examples of these include polyphenylene sulfide, polyphenylene sulfide sulfone, polyphenylene sulfide ketone, random copolymers thereof, block copolymers thereof, and mixtures thereof. Particularly preferred polyarylene sulfide resins include polyphenylene sulfide, polyphenylene sulfide sulfone, and polyphenylene sulfide ketone containing 80 mol% or more, particularly 90 mol% or more, of p-phenylene sulfide units as the main constituent units of the polymer.

[0020] [(a2) Elastomer] The (a2) elastomer of the present invention is a polymer compound having rubber elasticity.

[0021] The (a2) elastomer of the present invention preferably contains reactive functional groups, from the viewpoint of improving the fracture elongation and impact strength of the three-dimensional molded object by forming intermolecular bonds with the polyarylene sulfide resin, and from the viewpoint of preventing dragging of the molded object.

[0022] The dragging of the molded object in this invention refers to the phenomenon in which the surface to which resin powder particles are bonded in the layering direction is dragged when layering powder. This phenomenon occurs when a powder composition containing two or more resins with different thermal properties is used as raw material, and the three-dimensional molding conditions are set according to the thermal properties of the resin with high heat resistance, and molding is performed. In detail, the resin with low heat resistance melts during molding, and adheres the surface of the already bonded resin powder particles to the powder during layering, causing the molded object to be dragged as layering progresses. To avoid this phenomenon, it is necessary to prevent the resin with low heat resistance from functioning as an adhesive. To achieve this, the elastomer should not be dry-blended with the polyarylene sulfide resin powder, but rather dispersed within the polyarylene sulfide. Furthermore, when using a thermoplastic elastomer, it is preferable that the thermoplastic elastomer has reactive functional groups that can form intermolecular bonds with the polyarylene sulfide resin so that the thermoplastic elastomer does not bleed out from within the polyarylene sulfide resin. On the other hand, since thermosetting elastomers do not soften when heated, there is little concern about bleed-out even if they do not have reactive functional groups. However, from the viewpoint of improving elongation at break and impact strength, it is preferable to have reactive functional groups.

[0023] The reactive functional groups possessed by the (a2) elastomer of the present invention are not particularly limited, and specific examples include vinyl groups, epoxy groups, carboxyl groups, acid anhydride groups, ester groups, aldehyde groups, carbonyl dioxy groups, haloformyl groups, alkoxycarbonyl groups, amino groups, hydroxyl groups, styryl groups, methacrylic groups, acrylic groups, ureido groups, mercapto groups, sulfide groups, isocyanate groups, hydrolyzable silyl groups, oxazoline groups, etc., but among these, hydroxyl groups, epoxy groups, carboxyl groups, amino groups, acid anhydride groups, amino groups, hydroxyl groups, isocyanate groups, and oxazoline groups are preferred, and two or more of these reactive functional groups may be included.

[0024] From the viewpoint of improving the fracture elongation and impact strength of the three-dimensional fabricated object, the glass transition temperature Tg of the elastomer (a2) of the present invention is preferably 0°C or lower.

[0025] The preferred upper limit of the glass transition temperature Tg of the elastomer (a2) of the present invention is 0°C or less, more preferably -20°C or less, even more preferably -40°C or less, particularly preferably -60°C or less, significantly preferably -80°C or less, and most preferably -100°C or less.

[0026] Here, the glass transition temperature Tg of the elastomer (a2) of the present invention is defined as the midpoint obtained from the baseline of the baseline shift in the DSC curve detected when differential scanning calorimeter is used to measure differential scanning calorimetry from -120°C to 50°C at a heating rate of 20°C / min under a nitrogen atmosphere, and the tangent line at the inflection point is obtained from the baseline.

[0027] Specific examples of the (a2) elastomer of the present invention include thermoplastic elastomers such as olefin-based elastomers, polyester-based elastomers, styrene-based elastomers, and polyamide-based elastomers, and thermosetting elastomers such as silicone-based elastomers. From the viewpoint of improving the elongation at break and impact strength of three-dimensional molded products, olefin-based elastomers and silicone-based elastomers are preferred. From the viewpoint of compatibility with polyarylene sulfide, olefin-based elastomers are more preferred, and from the viewpoint of flame retardancy and chemical resistance, silicone-based elastomers are more preferred. These (a2) elastomers may be formulated not only as a single type, but also in combination of multiple types.

[0028] Examples of olefin-based elastomers include ethylene-butene copolymer, ethylene-propylene copolymer, ethylene-hexene copolymer, ethylene-octene copolymer, ethylene-vinyl acetate copolymer, ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-glycidyl methacrylate copolymer, ethylene-butyl acrylate copolymer, ethylene-methyl acrylate copolymer, ethylene-styrene copolymer, ethylene-methyl acrylate-glycidyl methacrylate copolymer, ethylene-ethyl acrylate-glycidyl methacrylate copolymer, and ethylene-vinyl acetate-glycidyl methacrylate copolymer. Among these, ethylene-butene copolymer, ethylene-propylene copolymer, ethylene-glycidyl methacrylate copolymer, ethylene-methyl acrylate-glycidyl methacrylate copolymer, ethylene-ethyl acrylate-glycidyl methacrylate copolymer, and ethylene-vinyl acetate-glycidyl methacrylate copolymer are preferred from the viewpoint of compatibility and dispersibility with polyarylene sulfide resin.

[0029] More specifically, examples include Sumitomo Chemical's "Bondfast" (registered trademark) E (ethylene:glycidyl methacrylate = 88% by weight: 12% by weight), "Bondfast" (registered trademark) 2C (ethylene:glycidyl methacrylate = 94% by weight: 6% by weight), "Bondfast" (registered trademark) 7L (ethylene:glycidyl methacrylate:methyl acrylate = 70% by weight: 3% by weight: 27% by weight), "Bondfast" (registered trademark) 7M (ethylene:glycidyl methacrylate:methyl acrylate = 67% by weight: 6% by weight: 27% by weight), "Bondfast" (registered trademark) CG5001 (ethylene:glycidyl methacrylate = 81% by weight: 19% by weight), and Arkema's "LOTADER" (registered trademark) AX8900 (ethylene:glycidyl methacrylate:methyl acrylate = 68% by weight: 8% by weight: 24% by weight).

[0030] Silicone elastomers have a main chain structure of organopolysiloxane and a molecular structure in which the intermolecules of organopolysiloxane are linked by crosslinking. Preferably, the degree of polymerization of the crosslinked silicone elastomer is 100 or higher, and the weight-average molecular weight is 10,000 or higher. The specific manufacturing method is not particularly limited, but for example, it can be obtained by emulsion curing an organopolysiloxane having at least two terminal active hydrogen functional groups per molecule and an oroganohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms per molecule.

[0031] Silicone elastomers can also be in forms that have copolymer components in part of their molecular structure. Specifically, this includes copolymers of organopolysiloxane components with one or more copolymer components selected from polyolefins (polyethylene, polypropylene, polybutylene, etc.), polycarbonates, polyamides, polybutylene terephthalate, polyester elastomers, polystyrene, polyetherimide, polyketones, liquid crystal polymers, polyetherketones, polyetheretherketones, polyacrylates (polymethyl methacrylate, etc.), etc. However, it is preferable that the silicone elastomer contains 90% or more by weight of constituent units derived from organopolysiloxane.

[0032] The organopolysiloxane structure of the silicone elastomer preferably contains one or more hydrocarbon groups selected from alkyl groups (methyl group, ethyl group, propyl group, butyl group, 2-ethylbutyl group, octyl group, etc.), cycloalkyl groups (cyclohexyl group, cyclopentyl group, etc.), alkenyl groups (vinyl group, propenyl group, butenyl group, heptenyl group, hexenyl group, allyl group, etc.), and aryl groups (phenyl group, tolyl group, xylyl group, naphthyl group, diphenyl group, etc.), with the presence of methyl groups and phenyl groups being particularly preferred.

[0033] Silicone elastomers can take the form of pellets, bulk, powder, powder aggregates, or flakes, but pellets, powder, powder aggregates, and flakes are preferred from the viewpoint of handling, processability, and dispersibility.

[0034] The average primary particle diameter of the silicone elastomer itself is preferably 5 μm or less, more preferably 4 μm or less, even more preferably 3 μm or less, and particularly preferably 1 μm or less, from the viewpoint of dispersibility, flame retardancy, and the toughness of the polyarylene sulfide resin composition. The average primary particle diameter (number-mean particle diameter) of the silicone elastomer itself can be calculated by randomly identifying the diameters of 100 particles from scanning electron microscope images and calculating their arithmetic mean. In the above images, if the particle is not perfectly circular, i.e., elliptical, the maximum diameter of the particle is used as its particle diameter.

[0035] Silicone-based elastomers may also be composites containing organopolysiloxane as a constituent unit. Core-shell rubber (silicone-acrylic core-shell rubber) in which silicone elastomer particles are covered with an acrylic component, or composite powders in which silicone elastomers are covered with silicone resin can also be used. However, from the viewpoint of flame retardancy and long-term durability, it is preferable that the organopolysiloxane content be 90% by weight or more.

[0036] Specifically, examples include Dow Toray's "Dowsil" (registered trademark) EP2600, "Dowsil" (registered trademark) EP2720, and Dow Toray's "Dowsil" (registered trademark) EP5500.

[0037] [Thermoplastic resin particles (A)] The thermoplastic resin particles (A) of the present invention are a thermoplastic resin composition obtained by blending (a2) elastomer in an amount of 1 to 40 parts by weight with (a1) polyarylene sulfide resin.

[0038] (a2) If the amount of elastomer is less than 1 part by weight, the fracture elongation and impact strength of the three-dimensional molded product will not improve. (a2) The lower limit of the amount of elastomer is preferably 1.2 parts by weight or more, and more preferably 1.5 parts by weight or more. (a2) If the amount of elastomer exceeds 40 parts by weight, the mechanical properties inherent to polyarylene sulfide will be impaired. (a2) The upper limit of the amount of elastomer is preferably 35 parts by weight or less, more preferably 30 parts by weight or less, even more preferably 25 parts by weight or less, particularly preferably 20 parts by weight or less, significantly preferably 15 parts by weight or less, and most preferably 10 parts by weight or less.

[0039] Methods for compounding the (a1) polyarylene sulfide resin of the present invention with the (a2) elastomer include compounding in a molten state and compounding in a solution state, but from the viewpoint of simplicity, compounding in a molten state is preferably used. For compounding in a molten state, melt kneading by an extruder or melt kneading by a kneader can be used, but from the viewpoint of productivity, melt kneading by an extruder that can produce continuously is preferably used. For melt kneading by an extruder, at least one extruder such as a single-screw extruder, twin-screw extruder, quadruple-screw extruder, or twin-screw single-screw composite extruder can be used, but from the viewpoint of kneadability, reactivity and productivity improvement, a twin-screw extruder or quadruple-screw extruder can be preferably used, and melt kneading by a twin-screw extruder is the most preferred.

[0040] (a1) The thermoplastic resin obtained by compounding (a2) the elastomer with the polyarylene sulfide resin is preferably pelletized in order to simplify the particle formation process described later.

[0041] As a more specific method of melt-kneading, although not necessarily limited thereto, it is preferable to use a twin-screw extruder with an L / D (L: screw length, D: screw diameter) of 10 or more, preferably 20 or more, and having two or more kneading sections, preferably three or more kneading sections. There is no particular limitation on the upper limit of L / D, but 60 or less is preferable from the viewpoint of economy. Also, there is no particular limitation on the upper limit of the number of kneading sections, but it is preferably 10 or less from the viewpoint of productivity. The ratio of the kneading section to the total screw length is preferably 5% or more, more preferably 10% or more, and still more preferably 15% or more from the viewpoint of the dispersibility of (a2) the elastomer in (a1) the polyarylene sulfide resin. On the other hand, the upper limit of the ratio of the kneading section to the total screw length is preferably 40% or less from the viewpoint of preventing deterioration of the resin due to excessive shear heat generation during kneading.

[0042] Regarding the screw rotation speed, a method of kneading under the conditions of 150 to 1000 revolutions / min, preferably 300 to 1000 revolutions / min, and more preferably 350 to 800 revolutions / min is preferable. When the screw rotation speed exceeds 150 revolutions / min, the kneading force is sufficient, so aggregation of (a2) the elastomer is suppressed, leading to the expression of the desired elongation at break and impact strength. When the screw rotation speed exceeds 1000 revolutions / min, deterioration of the resin and additives due to excessive shear heat generation during kneading occurs, leading to a decrease in elongation at break, impact strength, and mold fouling property, which is not preferable.

[0043] The preferable range of the cylinder temperature is specifically in the range of 280 to 400 °C, more preferably in the range of 280 to 360 °C, and still more preferably in the range of 280 to 330 °C.

[0044] There is no particular limitation on the mixing order of the raw materials during melt-kneading. Any method can be used, such as a method of melt-kneading all the raw materials by the above method after blending, a method of melt-kneading some of the raw materials by the above method, then blending and melt-kneading the remaining raw materials with this, or a method of blending some of the raw materials and using a side feeder to mix the remaining raw materials during melt-kneading by a twin-screw extruder.

[0045] The temperature of the thermoplastic resin particles (A) of the present invention during cooling crystallization is preferably 150°C or higher and 220°C or lower.

[0046] When the temperature of the thermoplastic resin particles (A) of the present invention during cooling crystallization is 150°C or higher, it is preferable because a shaped article with high strength can be obtained. The lower limit of the temperature of the polyarylene sulfide resin during cooling crystallization is more preferably 155°C or higher, further preferably 160°C or higher, and particularly preferably 165°C or higher. Further, when the temperature of the thermoplastic resin particles (A) during cooling crystallization is 220°C or lower, it is preferable because warping due to crystallization of the polyarylene sulfide resin melted by laser light irradiation can be suppressed. When warping occurs, it is dragged when laminating the upper layer, and a three-dimensional shaped article with a desired shape cannot be obtained. The upper limit of the temperature of the thermoplastic resin particles (A) during cooling crystallization is more preferably 210°C or lower, further preferably 205°C or lower, particularly preferably 200°C or lower, extremely preferably 195°C or lower, and most preferably 192°C or lower.

[0047] Here, the temperature of the thermoplastic resin particles (A) of the present invention during cooling crystallization, and the temperature of the resin particles (B), polyarylene sulfide resin, and powder composition described later during cooling crystallization are as follows: The thermoplastic resin particles (A), resin particles (B), polyarylene sulfide resin, and powder composition are heated from 50°C to 340°C at 20°C / min using a differential scanning calorimeter in a nitrogen atmosphere, held at 340°C for 5 minutes, and then cooled from 340°C to 50°C at 20°C / min. Among the exothermic peaks associated with crystallization observed at this time, the peak with the largest heat of exotherm is taken as the main peak, and its apex is taken as the temperature of the thermoplastic resin particles (A), resin particles (B), polyarylene sulfide resin, and powder composition during cooling crystallization.

[0048] In the morphology observed by an electron microscope, the thermoplastic resin particles (A) of the present invention preferably have (a1) the polyarylene sulfide resin as the matrix resin and (a2) the elastomer forming an island phase.

[0049] (a2) The formation of island phases in the elastomer suppresses the melting and bleeding out of the (a2) elastomer during the manufacturing of three-dimensional objects, and also makes it possible to obtain three-dimensional objects with high fracture elongation and impact strength.

[0050] (a2) The number-average dispersion particle size of the island phase of the elastomer is preferably 10 μm or less, and more preferably 10.0 μm or less.

[0051] When the number-mean-dispersed particle diameter of the island phase is 10 μm or less, the fracture elongation and impact strength of the three-dimensional fabricated object are improved, which is preferable. The number-mean-dispersed particle diameter of the island phase is more preferably 5.0 μm or less, even more preferably 2.0 μm or less, particularly preferably 1.0 μm or less, significantly preferably 0.5 μm or less, and most preferably 0.25 μm or less. There is no particular lower limit to the number-mean-dispersed particle diameter, but from the viewpoint of productivity, it is preferably 0.01 μm or more.

[0052] The number-mean-dispersed particle diameter of the island phase formed by the (a2) elastomer in the thermoplastic resin particle (A) of the present invention is determined by cutting a thin section of 0.1 μm or less from the center of the thermoplastic resin particle (A) in the cross-sectional direction, and then photographing the phase structure with a transmission electron microscope at a magnification of approximately 1000 to 5000 times. Next, the number-mean-dispersed particle diameter is determined from the major and minor axes of any 100 dispersed particles derived from the (a2) elastomer in the photograph using the following formula. The number-mean-dispersed particle diameter of the island phase formed by the (a2) elastomer in the thermoplastic resin composition constituting the three-dimensional molded object described later is determined by cutting a thin section of the three-dimensional molded object in the cross-sectional direction and photographing the phase structure with a transmission electron microscope.

[0053]

[0054] In the above formula, Mn is the number-average dispersion particle diameter of the dispersed phase of component (a2), a is the major axis, b is the minor axis, and n is the number of measurements, which is 100.

[0055] [Resin Particles B] The powder composition of the present invention may contain thermoplastic resin particles (A) and resin particles (B) made from a resin composition different from the thermoplastic resin composition that constitutes the thermoplastic resin particles (A).

[0056] The resin particles (B) of the present invention are composed of a resin composition different from the thermoplastic resin composition that constitutes the thermoplastic resin particles (A). The resin composition that constitutes the resin particles (B) preferably includes thermoplastic resins such as polyarylene sulfide resin (without elastomer), polyamide resin, polybutyl terephthalate resin, polypropylene resin, and polycarbonate resin, as well as thermosetting resins such as epoxy resin and acrylic resin. From the viewpoint of obtaining molded products without warping, a thermoplastic resin composition is preferred, and it is preferable to include (b) polyarylene sulfide resin which is different from (a1) polyarylene sulfide resin, and it is preferable to include (a1) polyarylene sulfide resin. The resin composition that constitutes the resin particles (B) may consist of only one type of resin, or it may be a combination of multiple resins of the same type, or a combination of multiple resins of different types, or it may contain organic or inorganic additives.

[0057] The cooling crystallization temperature of the resin particles (B) of the present invention is preferably 150°C or higher and 220°C or lower.

[0058] By mixing resin particles (B) having a cooling crystallization temperature of 150°C to 220°C into the powder composition, even if the cooling crystallization temperature of the thermoplastic resin particles (A) is not 150°C to 220°C, the cooling crystallization temperature of the powder composition described later can be adjusted to 150°C to 220°C.

[0059] It is preferable that the cooling crystallization temperature of the resin particles (B) of the present invention is 150°C or higher, as this improves the strength of the three-dimensional molded object. The lower limit of the cooling crystallization temperature of the resin particles (B) is more preferably 155°C or higher, even more preferably 160°C or higher, and particularly preferably 165°C or higher. Furthermore, it is preferable that the cooling crystallization temperature of the resin particles (B) is 220°C or lower, as this suppresses warping due to crystallization of the (b) resin melted by laser irradiation. If warping occurs, it will be dragged when stacking the upper layers, making it impossible to obtain a three-dimensional molded object with the desired shape. The upper limit of the cooling crystallization temperature of the resin particles (B) is more preferably 210°C or lower, even more preferably 205°C or lower, particularly preferably 200°C or lower, significantly preferably 195°C or lower, and most preferably 192°C or lower.

[0060] Here, the cooling crystallization temperature of the resin particles (B) of the present invention can be controlled by adjusting the cooling crystallization temperature of the resin (b). A method for adjusting the cooling crystallization temperature to a desired range when the resin (b) is a polyarylene sulfide resin (without elastomer) is described below. As a method for adjusting the cooling crystallization temperature of a polyarylene sulfide resin (without elastomer) to a desired range, one method is to add an organic acid metal salt or an inorganic acid metal salt to the polymerized polyarylene sulfide resin (without elastomer) and wash it. Such washing is preferably performed after removing residual oligomers and residual salts with hot water washing. Examples of organic acid metal salts or inorganic acid metal salts include, but are not limited to, calcium acetate, magnesium acetate, sodium acetate, potassium acetate, calcium propionate, magnesium propionate, sodium propionate, potassium propionate, calcium hydrochloride, magnesium hydrochloride, sodium hydrochloride, and potassium hydrochloride. The amount of such organic or inorganic metal acid salt added is preferably 0.01 to 5% by weight relative to the polyarylene sulfide resin (without elastomer). When washing the polyarylene sulfide resin (without elastomer), it is preferable to use an aqueous solution of such organic or inorganic metal acid salt, and the washing temperature is preferably 50°C to 90°C. The ratio of polyarylene sulfide resin (without elastomer) to aqueous solution is usually preferably selected as a bath ratio of 10 to 500 g of polyarylene sulfide resin (without elastomer) per liter of aqueous solution.

[0061] In the powder composition of the present invention, it is preferable that the total amount of thermoplastic resin particles (A) and resin particles (B) different from thermoplastic resin particles (A) is 100 parts by weight, and the content of thermoplastic resin particles (A) is 1 part by weight or more and 100 parts by weight or less.

[0062] A content of thermoplastic resin particles (A) of 1 part by weight or more is preferable because it improves the fracture elongation and impact strength of the three-dimensional molded product. The lower limit of the content of thermoplastic resin particles (A) is more preferably 2 parts by weight or more, even more preferably 3 parts by weight or more, and particularly preferably 5 parts by weight or more. A content of thermoplastic resin particles (A) of 100 parts by weight or less is preferable because it makes it easier to obtain molded products without warping. The upper limit of the content of thermoplastic resin particles (A) is more preferably 95 parts by weight or less, and even more preferably 90 parts by weight or less.

[0063] [Powder Composition] The D50 particle size of the powder composition of the present invention is 10 μm or more and 150 μm or less.

[0064] If the D50 particle size of the powder composition of the present invention is smaller than 10 μm, powder aggregation occurs, and surface roughness occurs due to the aggregates, resulting in the failure to produce a homogeneous three-dimensional object, and a three-dimensional object with high fracture elongation and impact strength cannot be obtained. The lower limit of the D50 particle size is preferably 15 μm or more, more preferably 20 μm or more, even more preferably 25 μm or more, and particularly preferably 30 μm or more. If the D50 particle size is larger than 150 μm, surface roughness occurs due to coarse particles, resulting in the failure to produce a homogeneous three-dimensional object, and a three-dimensional object with high fracture elongation and impact strength cannot be obtained. The upper limit of the D50 particle size is preferably 120 μm or less, more preferably 100 μm or less, even more preferably 90 μm or less, and particularly preferably 80 μm or less.

[0065] Here, the D50 particle size of the powder composition of the present invention is the particle size at which the cumulative frequency from the small particle size side of the particle size distribution, as measured by a laser diffraction particle size distribution analyzer based on Mie's scattering and diffraction theory, reaches 50%. The D10 particle size of the powder composition of the present invention is the particle size at which the cumulative frequency reaches 10%, and the D90 particle size of the powder composition of the present invention is the particle size at which the cumulative frequency reaches 90%.

[0066] The particle size distribution of the powder composition of the present invention is preferably uniform, and the D90 / D10 ratio in the particle size distribution of the powder composition is preferably 2 or more and 10 or less.

[0067] A D90 / D10 ratio of 10 or less is preferable because it allows for the formation of a uniform powder surface and the manufacture of a homogeneous three-dimensional object, thereby obtaining a three-dimensional object with high fracture elongation and impact strength. The upper limit of D90 / D10 is more preferably 8 or less, even more preferably 6 or less, particularly preferably 4 or less, and significantly preferably 3 or less. A D90 / D10 ratio of 2 or more is preferable because it increases the density of the three-dimensional object, improving its fracture elongation and impact strength. The lower limit of D90 / D10 is more preferably 2.2 or more, and even more preferably 2.5 or more.

[0068] The cooling crystallization temperature of the powder composition of the present invention is 150°C or higher and 220°C or lower.

[0069] If the cooling crystallization temperature of the powder composition of the present invention is less than 150°C, a molded object with high strength cannot be obtained. The lower limit of the cooling crystallization temperature of the powder composition is preferably 155°C or higher, more preferably 160°C or higher, and even more preferably 165°C or higher. Furthermore, if the cooling crystallization temperature of the powder composition exceeds 220°C, warping occurs due to the crystallization of the polyarylene sulfide resin melted by laser irradiation. When warping occurs, it drags when stacking the upper layer, making it impossible to obtain a three-dimensional molded object with the desired shape. The upper limit of the cooling crystallization temperature of the powder composition is preferably 210°C or lower, more preferably 205°C or lower, even more preferably 200°C or lower, particularly preferably 195°C or lower, and significantly preferably 192°C or lower.

[0070] The powder composition of the present invention may contain an inorganic reinforcing material (C) to improve its mechanical properties.

[0071] The size of the inorganic reinforcing material (C) used in this invention is not particularly limited, but materials with a maximum dimension of 1 μm or more and 400 μm or less can be used. A maximum dimension of 1 μm or more is preferable because it can further improve the mechanical properties of the three-dimensional molded object. The lower limit of the maximum dimension is more preferably 20 μm or more, and more preferably 50 μm or more. Furthermore, a maximum dimension of 400 μm or less is preferable because it improves the fluidity of the powder composition, and the upper limit of the maximum dimension is more preferably 200 μm or less, and even more preferably 170 μm or less.

[0072] Here, the maximum dimension is the average value obtained by observing the inorganic reinforcement material (C) using an electron microscope, randomly selecting 100 inorganic reinforcement material (C) from images magnified between 10,000 and 100,000 times, and measuring the length at which the distance between two points on the outer contour line of each inorganic reinforcement material (C) is maximized.

[0073] When the inorganic reinforcing material (C) is fibrous, it is preferable that the fiber diameter is 0.1 μm or more and 50 μm or less. A more preferable lower limit for the fiber diameter is 0.5 μm, and particularly preferable is 1 μm. A more preferable upper limit for the fiber diameter is 40 μm, and particularly preferable is 30 μm.

[0074] Examples of the inorganic reinforcing material (C) of the present invention include talc, silica-containing compounds, minerals, glass fibers, glass beads, glass flakes, foamed glass beads, single-crystal potassium titanate, carbon fibers, carbon nanotubes, carbon black, anthracite powder, titanium oxide, magnesium oxide, potassium titanate, mica, asbestos, calcium sulfite, calcium silicate, molybdenum sulfide, boron fibers, silicon carbide fibers, etc., but carbon fibers, glass fibers, and glass beads are preferred. These inorganic reinforcing materials can be used individually or in combination of two or more types.

[0075] The volume resistivity of the carbon fibers used in this invention is preferable because a lower volume resistivity reduces the likelihood of fiber aggregation due to static charge when mixing them as a powder mixture. Preferably, the volume resistivity is 20 × 10⁻⁴ Ω·cm or less. Here, volume resistivity is the value obtained by measuring the electrical resistance of a carbon fiber bundle cut from roving and using the following formula: Volume resistivity = Resistivity (Ω) × Carbon fiber bundle width (mm) × Carbon fiber bundle thickness (mm) × Carbon fiber bundle length (mm)

[0076] The powder composition of the present invention preferably contains 10 to 100 parts by weight of an inorganic reinforcing material (C), with a total of 100 parts by weight of thermoplastic resin particles (A) and resin particles other than thermoplastic resin particles (B).

[0077] A content of 10 parts by weight or more of inorganic reinforcing material (C) is preferable because it improves the impact strength of the three-dimensional molded object. The lower limit of the inorganic reinforcing material (C) content is more preferably 15 parts by weight or more, even more preferably 25 parts by weight or more, particularly preferably 30 parts by weight or more, and significantly preferably 35 parts by weight or more. A content of 100 parts by weight or less of inorganic reinforcing material (C) is preferable because it improves the elongation at break of the three-dimensional molded object. The upper limit of the inorganic reinforcing material (C) content is more preferably 80 parts by weight or less, even more preferably 70 parts by weight or less, and particularly preferably 60 parts by weight or less.

[0078] The powder composition of the present invention may contain inorganic fine particles (D) to improve fluidity.

[0079] In the present invention, inorganic fine particles (D) can be added to further improve the fluidity of the powder composition. The fluidity of a powder composition deteriorates due to interactions with neighboring particles when the size of thermoplastic resin particles is small, but by adding inorganic fine particles (D) which have a smaller particle size than thermoplastic resin particles, the interparticle distance can be increased, and the fluidity of the powder composition tends to be improved.

[0080] In the present invention, the D50 particle size of the inorganic fine particles (D) is preferably 20 nm or more and 500 nm or less.

[0081] When the D50 particle diameter of the inorganic fine particles (D) of the present invention is 20 nm or more, aggregation of the inorganic fine particles (D) is suppressed, a uniform powder surface can be formed, and a homogeneous three-dimensional object can be manufactured, which is preferable as it is possible to obtain a three-dimensional object with high fracture elongation and impact strength. The lower limit of the D50 particle diameter of the inorganic fine particles (D) is more preferably 30 nm or more, even more preferably 40 nm or more, and particularly preferably 50 nm or more. When the D50 particle diameter of the inorganic fine particles (D) is 500 nm or less, the fluidity of the powder composition is improved, a uniform powder surface can be formed, and a homogeneous three-dimensional object can be manufactured, which is preferable as it is possible to obtain a three-dimensional object with high fracture elongation and impact strength. The upper limit of the D50 particle diameter of the inorganic fine particles (D) is more preferably 400 nm or less, even more preferably 300 nm or less, particularly preferably 250 nm or less, and significantly preferably 200 nm or less. Here, the D50 particle size is a value measured in the same manner as the D50 particle size of the powder composition described above.

[0082] Examples of the inorganic fine particles (D) of the present invention include calcium carbonate particles, silica (silicon dioxide) fine particles, fused silica particles, crystalline silica particles, alumina (aluminum oxide) particles, alumina-containing compound particles, and aluminum particles. Silica fine particles are preferred, and among these, amorphous silica particles, which have low toxicity to the human body, are industrially extremely preferred.

[0083] The shape of the inorganic fine particles (D) can be spherical, porous, hollow, or irregular in shape, and the shape of the inorganic fine particles (D) in this invention is not particularly limited, but a spherical shape is preferred because it exhibits good fluidity.

[0084] The powder composition of the present invention preferably contains 0.1 to 10 parts by weight of inorganic fine particles (D), with a total of 100 parts by weight of thermoplastic resin particles (A) and resin particles other than thermoplastic resin particles (B).

[0085] Including 0.1 parts by weight or more of the inorganic fine particles (D) of the present invention improves the fluidity of the powder composition and allows for the formation of a uniform powder surface, thus enabling the manufacture of homogeneous three-dimensional molded objects. This is preferable because it improves the elongation at break and impact strength of the three-dimensional molded objects. The lower limit of the inorganic fine particles (D) content is more preferably 0.2 parts by weight or more, and even more preferably 0.3 parts by weight or more. Including more than 10 parts by weight of inorganic fine particles (D) may cause sintering defects and reduce the elongation at break and impact strength of the three-dimensional molded objects. Therefore, the upper limit of the inorganic fine particles (D) content is more preferably 6 parts by weight or less, and even more preferably 2 parts by weight or less.

[0086] In the powder composition of the present invention, both the inorganic reinforcing material (C) and the inorganic fine particles (D) described above may be included in amounts within the preferred range described above.

[0087] The inorganic reinforcing material (C) and inorganic fine particles (D) of the present invention are preferably dry-blended in order to improve fluidity.

[0088] Furthermore, the powder composition of the present invention may contain other additives. Examples of other additives include antioxidants, heat stabilizers, weathering agents, lubricants, pigments, dyes, plasticizers, antistatic agents, flame retardants, carbon black, and titanium dioxide, which improve the stability of the powder composition.

[0089] Preferably, the tensile elongation at break in the X direction of a dumbbell test specimen prepared using the powder composition of the present invention as a raw material by a powder bed fusion bonding method, measured according to ISO 527-2 (2012), is 1.5% or more. Note that the direction in which the recoater moves, as described later, is defined as the X direction.

[0090] A tensile elongation at break in the X direction of 1.5% or more is preferable because it indicates high elongation at break and expands the range of applications for the resulting three-dimensional object. A tensile elongation at break in the X direction of 1.6% or more is more preferable, 1.7% or more is even more preferable, and 1.8% or more is particularly preferable.

[0091] The tensile elongation at break in this invention was measured using a Tensilon universal testing machine RTG-1250 (manufactured by A&D Co., Ltd.).

[0092] The Charpy impact strength (without notches) in the X direction of a test specimen cut from a dumbbell test piece prepared in accordance with ISO 527-2 (2012) using the powder composition of the present invention as a raw material by powder bed fusion bonding was 3.5 kJ / m², measured according to ISO 179 (2010). ２ It is preferable that the above conditions are met.

[0093] The Charpy impact strength (without notches) is 3.5 kJ / m ２ The above specifications result in high impact resistance, which is desirable as it expands the range of applications for the resulting three-dimensionally fabricated object. The Charpy impact strength (without notches) is 4.0 kJ / m ２ The above is more preferable, with a 4.2 kJ / m ２ The above is even more preferable.

[0094] The Charpy impact strength (without notch) in this invention was measured using a digital impact tester DG-UB (manufactured by Toyo Seiki Seisakusho Co., Ltd.).

[0095] [Method for Producing Thermoplastic Resin Particles] The method for producing thermoplastic resin particles of the present invention is not particularly limited. Particles obtained by polymerization can be used as thermoplastic resin particles, or particles can be obtained from resins that have been made into pellets, fibers, or films. Furthermore, depending on the form of thermoplastic resin particles used, the pulverization treatment described below can be performed. Other methods include a spray-drying method in which raw materials are dissolved in a solvent, a poor solvent precipitation method in which an emulsion is formed in a solvent and then brought into contact with a poor solvent, a liquid-drying method in which an emulsion is formed in a solvent and then the organic solvent is dried off, and a forced melt-kneading method in which a sea-island structure is formed by mechanically kneading the resin component to be particleized with a different resin component, and then the sea component is removed with a solvent. Among these, pulverization is preferably used from the viewpoint of economy. There are no particular limitations on the pulverization method, and examples include disc mills, jet mills, bead mills, hammer mills, ball mills, sand mills, turbo mills, and cryogenic pulverization. Preferably, dry pulverization such as turbo mills, jet mills, and cryogenic pulverization is used, and more preferably, cryogenic pulverization is used.

[0096] After the production of thermoplastic resin particles, coarse and fine particles can be removed by known methods to adjust them to the desired particle size and particle size distribution. For example, methods such as physical removal using a specified filter, airflow classification separating particles while applying compressed air during weeding, and separation by buoyancy difference in a liquid phase can be used. However, from the viewpoint of separation accuracy, a method of passing the particles through a filter with a specified mesh size is preferred.

[0097] The mesh size of the filter is preferably 45 μm or more and 250 μm or less. A mesh size of 45 μm or more is preferable because it improves the productivity of classification by the filter. A mesh size of 60 μm or more is more preferable. A mesh size of 250 μm or less is preferable because it allows adjustment to the desired D50 particle size and particle size distribution. A mesh size of 200 μm or less is more preferable, 180 μm or less is even more preferable, 125 μm or less is particularly preferable, and 90 μm or less is extremely preferable.

[0098] [Method for manufacturing a three-dimensional object] The method for manufacturing a three-dimensional object of the present invention involves supplying the above-described powder composition to a three-dimensional object manufacturing apparatus.

[0099] The powder bed fusion method is preferred as the fabrication method for the three-dimensional object of the present invention. The powder bed fusion method is a manufacturing method in which a three-dimensional object is obtained by repeatedly forming a layer of powder composition, melting and welding the position corresponding to the cross-section of the desired object using a heat source such as a laser, and then forming another layer of powder composition on top of it. Details of this method are illustrated with Figure 1.

[0100] (a) In step (a), the stage 2 of the tank 1 in which the molded object is formed is lowered.

[0101] (b) In step (b), the stage 4 of the tank 3 (hereinafter sometimes referred to as the supply tank), which is pre-filled with the powder composition P to be supplied to the tank 1 for forming the molded object, is raised to a height that allows for the supply of a sufficient amount of powder composition P to fill the tank 1 to a predetermined stacking height. Then, the recoater 5 is moved from the left end of the supply tank 3 in the diagram to the right end of the tank 1, and the powder composition P is stacked in the tank 1. The direction parallel to the movement of the recoater 5 is the X direction, and the direction perpendicular to the direction of movement of the recoater 5 on the powder surface of the powder composition P is the Y direction. Reference numeral 7 indicates a coordinate system representing the X, Y, and Z directions. Reference numeral 8 indicates the surface direction in which the powder composition P is stacked, and reference numeral 9 indicates the height direction in which the powder composition P is stacked.

[0102] (c) In step (b), the powder composition P, which was filled into the tank 1 to a predetermined stacking height in step (b), is given meltable thermal energy 6 to selectively melt and sinter according to the molding data.

[0103] In the powder bed fusion method, a three-dimensional object 10 can be obtained by repeatedly performing steps (a) to (c) described above.

[0104] Furthermore, the powder composition supplied to the powder bed fusion three-dimensional manufacturing apparatus can be recovered as appropriate and, for example, regenerated by melting and pulverizing it, or it can be processed to remove molten resin other than the powder composition using a sieve with a mesh size of 1 mm and then supplied to the three-dimensional manufacturing apparatus again, either as is or mixed with unused powder composition.

[0105] Powder bed fusion is further classified into selective laser sintering and multi-jet fusion depending on how thermal energy 6 is applied to the powder composition in step (c). Selective laser sintering is a method in which a laser is irradiated to a shape corresponding to the cross-sectional shape of the object to be fabricated, thereby bonding the powder composition. Multi-jet fusion is a method in which an energy absorption accelerator is applied to a shape corresponding to the cross-sectional shape of the object to be fabricated, or an energy absorption inhibitor is applied to the non-sintered surface, and the resin powder is bonded using electromagnetic radiation.

[0106] The laser light used in selective laser sintering is not particularly limited as long as it does not impair the quality of the polymer particles or polymer particle composition or the fabricated object. Examples include carbon dioxide lasers, YAG lasers, excimer lasers, He-Cd lasers, and semiconductor-pumped solid-state lasers. Among these, carbon dioxide lasers are preferred because they are easy to operate and control.

[0107] Furthermore, while any electromagnetic radiation can be used in the multi-jet fusion method as long as it does not impair the quality of the powder composition or the fabricated object, infrared radiation is preferred because it is relatively inexpensive and provides energy suitable for fabrication. Also, the electromagnetic radiation may or may not be coherent.

[0108] Energy absorption enhancers are substances that absorb electromagnetic radiation. Examples of such substances include carbon black, carbon fibers, copper hydroxyphosphate, near-infrared absorbing dyes, near-infrared absorbing pigments, metal nanoparticles, polythiophene, poly(p-phenylene sulfide), polyaniline, poly(pyrrole), polyacetylene, poly(p-phenylene vinylene), polyparaphenylene, poly(styrene sulfonate), poly(3,4-ethylenedioxythiophene)-poly(styrenephosphonate)p-diethylaminobenzaldehyde diphenylhydrazone, or conjugated polymers consisting of combinations thereof. These may be used individually or in combination.

[0109] Energy absorption inhibitors are substances that do not readily absorb electromagnetic radiation. Examples of such substances include materials that reflect electromagnetic radiation, such as titanium, heat-insulating powders such as mica powder and ceramic powder, and water. These can be used individually or in combination.

[0110] These selective absorbers or selective inhibitors may be used individually or in combination.

[0111] In the process of printing a selective absorbent or selective inhibitor in a shape corresponding to the cross-sectional shape of the object to be fabricated, known methods such as inkjet printing can be used. In this case, the selective absorbent or selective inhibitor may be used as is, or it may be dispersed or dissolved in a solvent before use.

[0112] [Three-dimensional molded object] In the three-dimensional molded object of the present invention, the thermoplastic resin composition constituting the three-dimensional molded object has, in the morphology observed by electron microscope, a polyarylene sulfide resin (a1) as the matrix resin and (a2) elastomer forming island phases, and the number-average dispersion particle diameter of the island phases is 10 μm or less, preferably 10.0 μm or less.

[0113] When the number-mean-dispersed particle diameter of the island phase is 10 μm or less, the fracture elongation and impact strength of the three-dimensional fabricated object are improved. The upper limit of the number-mean-dispersed particle diameter of the island phase is preferably 5.0 μm or less, more preferably 2.0 μm or less, even more preferably 1.0 μm or less, particularly preferably 0.5 μm or less, and significantly preferably 0.25 μm or less. There is no particular lower limit to the number-mean-dispersed particle diameter, but from the viewpoint of productivity, it is preferably 0.01 μm or more.

[0114] The number-mean-average dispersion particle diameter of the island phase formed by the (a2) elastomer in the thermoplastic resin composition constituting the three-dimensional object is determined by cutting a thin section of 0.1 μm or less from the center of the three-dimensional object in the cross-sectional direction, and then photographing the phase structure with a transmission electron microscope at a magnification of approximately 1000 to 5000 times. Subsequently, the number-mean-average dispersion particle diameter is calculated from the major and minor axes of any 100 dispersed particles derived from the (a2) elastomer in the photograph using the following formula.

[0115]

[0116] In the above formula, Mn is the number-average dispersion particle diameter of the dispersed phase of component (a2), a is the major axis, b is the minor axis, and n is the number of measurements, which is 100.

[0117] The present invention will be described below based on examples, but the present invention is not limited to these examples.

[0118] (1) Method for measuring the cooling and crystallization temperature of polyarylene sulfide resin, thermoplastic resin particles (A), resin particles (B), powder composition, or three-dimensional molded object A differential scanning calorimeter (DSCQ20) manufactured by TA Instruments Inc. was used to measure 10 mg of polyarylene sulfide resin, thermoplastic resin particles (A), resin particles (B), powder composition, or three-dimensional molded object under the following conditions in a nitrogen atmosphere: - Hold at 50°C for 1 minute - Increase temperature from 50°C to 340°C at a heating rate of 20°C / min - Hold at 340°C for 5 minutes - Cool down from 340°C to 50°C at a cooling rate of 20°C / min

[0119] Among the exothermic peaks associated with crystallization during cooling, the peak with the largest amount of heat generation was designated as the main peak, and its peak was defined as the cooling crystallization temperature for the polyarylene sulfide resin, thermoplastic resin particles (A), resin particles (B), powder composition, or three-dimensional molded object.

[0120] (2) Method for measuring D50 particle size and D90 / D10 of the powder composition A laser diffraction particle size distribution analyzer (Microtrac MT3300EXII) manufactured by Nikkiso Co., Ltd. was used, and a 0.5 wt% aqueous solution of polyoxyethylene cumylphenyl ether (trade name Nonal 912A, manufactured by Toho Chemical Industry Co., Ltd., hereafter referred to as Nonal 912A) was used as the dispersion medium for measurement. Specifically, the cumulative curve was determined by analyzing the scattered light of the laser using the Microtrac method, with the total volume of fine particles set to 100%, and the particle size at the point where the cumulative curve from the small particle size side reaches 10% was set to D10, the particle size at the point where it reaches 50% was set to D50, and the particle size at the point where it reaches 90% was set to D90.

[0121] (3) Tensile elongation at fracture of three-dimensionally fabricated objects The tensile elongation at fracture of three-dimensionally fabricated objects was measured using a Tensilon universal tester RTG-1250 (manufactured by A&D Co., Ltd.) in accordance with ISO 527-2 (2012), after ISO 1A type test specimens were prepared using a powder sintering 3D printer.

[0122] (4) Charpy impact strength of three-dimensionally fabricated objects (without notches) The Charpy impact strength (without notches) of three-dimensionally fabricated objects was evaluated using a digital impact tester DG-UB (manufactured by Toyo Seiki Seisakusho Co., Ltd.) in accordance with ISO 179 (2010), using test specimens obtained by cutting ISO 1A type test specimens fabricated using a powder sintering 3D printer.

[0123] (5) Number-average dispersion particle diameter of the dispersed phase of component (a2) in thermoplastic resin particles (A) and three-dimensional molded object After cutting a thin section of 0.1 μm or less from the center of the thermoplastic resin particles (A) or three-dimensional molded object in the cross-sectional area direction, the phase structure is photographed with a transmission electron microscope at a magnification of approximately 1000 to 5000 times. Next, the number-average dispersion particle diameter is determined from the major and minor axes of any 100 dispersed particles originating from component (a2) in the photographed image using the following formula.

[0124]

[0125] In the above formula, Mn is the number-average dispersion particle diameter of the dispersed phase of component (a2), a is the major axis, b is the minor axis, and n is the number of measurements, which is 100.

[0126] [Synthesis Example 1] Synthesis of Polyarylene Sulfide Resin (I) 1.00 mole of 47% by weight sodium hydrosulfide, 1.05 moles of 46% by weight sodium hydroxide, 1.65 moles of N-methyl-2-pyrrolidone (NMP), 0.45 moles of sodium acetate, and 5.55 moles of deionized water were charged into a 1-liter autoclave equipped with a stirrer. The mixture was gradually heated to 225°C over approximately 2 hours under atmospheric pressure while passing nitrogen through it. After distilling off 11.70 moles of water and 0.02 moles of NMP, the reaction vessel was cooled to 160°C. The amount of hydrogen sulfide released was 0.01 moles.

[0127] Next, 1.02 moles of p-dichlorobenzene (p-DCB) and 1.32 moles of NMP were added, and the reaction vessel was sealed under nitrogen gas. Then, while stirring at 400 rpm, the temperature was raised in two stages: from 200°C to 240°C in 90 minutes, and from 240°C to 270°C in 30 minutes. Ten minutes after reaching 270°C, 0.75 moles of water were injected into the system over 15 minutes. After 120 minutes at 270°C, the mixture was cooled to 200°C at a rate of 1.0°C / min, and then rapidly cooled to near room temperature to remove the contents.

[0128] The contents were removed, diluted with 0.5 liters of NMP, and the solvent and solids were filtered off using a sieve (80 mesh). The resulting particles were washed several times with 1 liter of warm water, then 800 g of a 0.55 wt% aqueous acetic acid solution was added to the polyarylene sulfide resin and washed. The mixture was then washed again with 1 liter of warm water and filtered to obtain a cake. The obtained cake was dried under a nitrogen stream at 120°C to obtain polyarylene sulfide resin (I). The cooling crystallization temperature of the obtained polyarylene sulfide resin (I) was 231°C.

[0129] [Synthesis Example 2] Polyarylene sulfide resin (II) was synthesized in the same manner as in Synthesis Example 1, except that 800 g of 0.45% by weight calcium acetate monohydrate was added to the polyarylene sulfide resin instead of the aqueous acetic acid solution. The cooling crystallization temperature of the obtained polyarylene sulfide resin (II) was 168°C. The cooling crystallization temperatures for Synthesis Examples 1 and 2 are summarized in Table 1.

[0130]

[0131] [Manufacturing Example 1-4] The elastomers prepared in the manufacturing example are shown below. (a2)-1 Olefin-based elastomer: Ethylene-glycidyl methacrylate-methyl acrylate copolymer (Sumitomo Chemical's "Bond First" (registered trademark) 7M, ethylene:glycidyl methacrylate:methyl acrylate = 67% by volume:6% by mass:27% by mass) (a2)-2 Silicone-based elastomer: Silicone rubber (Dow Toray's "Dowsil" (registered trademark) EP5500, polyorganosiloxane content: approximately 90% or more, average primary particle size: 3 μm)

[0132] In the manufacturing example, the compatibilizer prepared is shown below. (a3)-1 Silane coupling agent 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane (KBM-303, manufactured by Shin-Etsu Chemical Co., Ltd.)

[0133] The polyarylene sulfide resin obtained in the synthesis example, (a2) elastomer, and (a3) ​​compatibilizer were dry-blended in the proportions shown in Table 2, and then fed into a TEX30α twin-screw extruder (L / D=30, 2 kneading sections) manufactured by Japan Steel Works Ltd., and melt-kneaded. The kneading conditions were 300°C and 300 rpm. After pelletizing with a strand cutter, the mixture was dried at 130°C for 3 hours. The obtained pellets were freeze-dried for 120 minutes and then passed through a sieve with a mesh size of 125 μm to obtain thermoplastic resin particles (A) ((A)-1 to (A)-4). The properties of the obtained particles are shown in Table 2. Figure 2 shows a transmission electron microscope image of the cross-section of thermoplastic resin particle (A)-1 obtained in Production Example 1.

[0134] [Manufacturing Example 5] Manufacturing of resin particles (B) The polyarylene sulfide resin obtained in Synthesis Example 2 was pulverized by freeze-drying for 120 minutes to obtain resin particles (B) with a cooling crystallization temperature of 168°C. The properties of the obtained particles are shown in Table 2.

[0135]

[0136] The inorganic fine particles prepared in the example are shown below. (D)-1 Inorganic fine particles: Trimethylsilylated amorphous silica (X-24-9500, manufactured by Shin-Etsu Chemical Co., Ltd.)

[0137] [Examples 1-6, Comparative Example 1] Thermoplastic resin particles (A), resin particles (B), and inorganic fine particles (D) were dry-blended in the proportions shown in Table 3 to obtain a powder composition. Three-dimensional objects were then fabricated using this powder composition with a powder sintering 3D printer (Aspect Corporation's Rafael II 300C-HT). The properties of the obtained powder composition and three-dimensional objects are shown in Table 3. Figure 3 shows a transmission electron microscope image of the cross-section of the three-dimensional object obtained in Example 2.

[0138] [Comparative Example 2] Thermoplastic resin particles (A) and resin particles (B) were dry-blended in the proportions shown in Table 3 to obtain a powder composition. This powder composition was then used to fabricate a three-dimensional object using a powder sintering 3D printer (Rafael II 300C-HT manufactured by Aspect). However, the object warped and dragged, resulting in an inaccurate object.

[0139]

[0140] The powder composition of the present invention contains an elastomer, and because the cooling crystallization temperature of the powder composition is low, it is possible to provide polyarylene sulfide molded products with high fracture elongation and impact strength, and no warping.

[0141] 1. Tank for forming the object 2. Stage of the tank for forming the object 3. Supply tank for pre-filling with the supplied powder composition 4. Stage of the tank for pre-filling with the supplied powder composition 5. Recoater 6. Thermal energy 7. X, Y, Z coordinate system 8. Planar direction for layering the powder composition 9. Height direction for layering the powder composition 10. Three-dimensional object P Powder composition

Claims

1. A powder composition for three-dimensional molded objects comprising thermoplastic resin particles (A), wherein the thermoplastic resin composition constituting the thermoplastic resin particles (A) is a thermoplastic resin composition comprising (a1) 100 parts by weight of polyarylene sulfide resin and (a2) elastomer in a ratio of 1 part by weight to 40 parts by weight, wherein the D50 particle diameter of the powder composition is 10 μm or more and 150 μm or less, and the cooling crystallization temperature of the powder composition is 150°C or more and 220°C or less.

2. The powder composition according to claim 1, characterized in that the elastomer (a2) has a reactive functional group.

3. The powder composition according to claim 1, characterized in that the glass transition temperature (Tg) of the elastomer (a2) is 0°C or lower.

4. The powder composition according to claim 1, characterized in that the (a2) elastomer is at least one selected from the group consisting of olefin-based elastomers and silicone-based elastomers.

5. The powder composition according to claim 1, characterized in that, in the morphology observed by electron microscope, the thermoplastic resin particles (A) consist of (a1) a polyarylene sulfide resin as the matrix resin and (a2) an elastomer forming an island phase, wherein the number-average dispersion particle diameter of the island phase is 10 μm or less.

6. The powder composition according to claim 1, wherein the D90 / D10 in the particle size distribution of the powder composition is 2 or more and 10 or less.

7. The powder composition according to claim 1, wherein the powder composition comprises thermoplastic resin particles (A) and resin particles (B) composed of a resin composition different from the thermoplastic resin composition constituting the thermoplastic resin particles (A), wherein the resin composition constituting the resin particles (B) includes at least one selected from the group consisting of (a1) polyarylene sulfide resin and (b) polyarylene sulfide resin different from (a1) polyarylene sulfide resin, and the cooling crystallization temperature of the resin particles (B) is 150°C or higher and 220°C or lower.

8. The powder composition according to claim 7, characterized in that the total amount of thermoplastic resin particles (A) and resin particles (B) is 100 parts by weight, and the content of thermoplastic resin particles (A) is 1 part by weight or more and 100 parts by weight or less.

9. The powder composition according to claim 1, characterized in that the cooling crystallization temperature of the thermoplastic resin particles (A) is 150°C or higher and 220°C or lower.

10. The powder composition according to claim 1, wherein the powder composition contains 100 parts by weight or more of an inorganic reinforcing material (C), with a total of 100 parts by weight of thermoplastic resin particles (A) and resin particles (B) composed of a resin composition different from the thermoplastic resin composition constituting the thermoplastic resin particles (A).

11. The powder composition according to claim 1, wherein the powder composition comprises 0.1 to 10 parts by weight of inorganic fine particles (D) with a D50 particle size of 20 nm to 500 nm, with a total of 100 parts by weight of thermoplastic resin particles (A) and resin particles (B) composed of a resin composition different from the thermoplastic resin composition constituting the thermoplastic resin particles (A).

12. The powder composition according to claim 1, wherein when a dumbbell test specimen is prepared by powder bed fusion bonding in accordance with ISO 527-2 (2012) such that its longitudinal direction is parallel to the direction in which the recoater moves (X direction), the tensile elongation at break of the test specimen in the X direction, measured according to ISO 527-2 (2012), is 1.5% or more.

13. Using a powder bed fusion bonding method, a dumbbell specimen was prepared in accordance with ISO 527-2 (2012), with the longitudinal direction parallel to the direction of recoater movement (X direction). The Charpy impact strength (without notches) of a specimen cut from the parallel section of the obtained dumbbell specimen was measured according to ISO 179 (2010) and was 3.5 kJ / m². ２ The powder composition according to claim 1 is as described above.

14. A method for producing thermoplastic resin particles (A) comprising the following steps (1) to (3): (1) A step of melt-kneading (a1) polyarylene sulfide resin with (a2) elastomer in an amount of 1 to 40 parts by weight, and then pelletizing the mixture. (2) A step of crushing the pellets obtained in step (1). (3) A step of passing the particles crushed in step (2) through a filter with a mesh size of 45 μm to 250 μm.

15. A method for manufacturing a three-dimensional object, comprising supplying a powder composition according to any one of claims 1 to 13 to a powder bed fusion bonding type three-dimensional object manufacturing apparatus.

16. A three-dimensional object characterized in that, in the morphology observed by an electron microscope, the thermoplastic resin composition constituting the three-dimensional object has (a1) a polyarylene sulfide resin as the matrix resin and (a2) an elastomer forming an island phase, wherein the number-average dispersion particle diameter of the island phase is 10 μm or less.

17. A three-dimensional object according to claim 16, obtained by a powder bed fusion bonding method using the powder composition according to any one of claims 1 to 13.

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