Powder composition, method for producing three-dimensional shaped object, and three-dimensional shaped object

Abstract

Provided is a powder composition (C) that contains a polyarylene sulfide resin powder (A) and an inorganic reinforcing material (B). The polyarylene sulfide resin powder (A) has a number average particle diameter of 1-100 μm. The inorganic reinforcing material (B) has an average long axis diameter of 10 -150 μm. The inorganic reinforcing material (B) is contained at a quantity of 20-60 wt% relative to the total weight of the powder composition (C). At a temperature that is 30°C higher than the melting point of the polyarylene sulfide resin powder (A), the loss tangent of the powder composition (C) is 3-25. By using this powder composition, it is possible to obtain a three-dimensional shaped object having excellent rigidity and heat resistance and high strength even if a residual powder that has been used for three-dimensional shaping is recycled and shaped.

Description

Powder composition, method for producing three-dimensional shaped object, and three-dimensional shaped object

[0001] The present invention relates to a powder composition, a method for producing a three-dimensional structure, and a three-dimensional structure obtained thereby.

[0002] Three-dimensional (3D) manufacturing allows for a high degree of freedom in designing shapes, and is therefore widely used in applications such as automobiles, aerospace, various industries, and medicine. Powder bed fusion (PBM) is a suitable manufacturing method because it can achieve precision manufacturing and mechanical strength and does not require support members. The manufacturing process of PBM involves sequentially repeating a thin layer formation process in which resin powder is spread into a thin layer, and a cross-sectional shape formation process in which a laser beam is irradiated onto the formed thin layer in a shape corresponding to the cross-sectional shape of the object to be manufactured, thereby bonding the powder.

[0003] While polyamide 12 resin has traditionally been widely used as the material for the resin powder described above for the purpose of shape confirmation, in recent years, advances in application development have led to consideration of applications such as functional prototyping to confirm the performance of designed shapes and end product applications using actual three-dimensional shaped objects, which have increased demands for heat resistance and rigidity. Therefore, there is a demand for the application of highly functional materials such as polyarylene sulfide resins, typified by polyphenylene sulfide resins (hereinafter sometimes referred to as PPS resins), which have excellent rigidity, heat resistance, and the like.

[0004] When applying these highly functional materials, it is extremely important that the 3D-printed object has a certain level of performance, i.e., stable quality and reliability. However, in powder bed fusion (PBF) processes, the majority of the powder used does not end up in the molded object but is instead recovered as residual powder. It is preferable to reuse the residual powder in molding to reduce powder waste (hereinafter, sometimes simply referred to as "recycled molding"). However, because the residual powder is exposed to temperatures slightly below its melting point for a long period of time during molding, it is denatured compared to unused, new powder, which poses a problem of reduced quality and reliability for 3D-printed objects.

[0005] For example, Patent Document 1 discloses a technology for reducing voids generated in a molded object and improving the tensile strength of the molded object by using a polyarylene sulfide resin with an appropriate amount of gas generated and melt flow rate for powder bed fusion. Patent Document 2 discloses a good recycling molding technology for suppressing the deterioration of polyarylene sulfide resin powder by setting appropriate temperature conditions in three-dimensional molding.

[0006] International Publication No. 2022-250003 Special Publication No. 2022-545634

[0007] However, although Patent Document 1 can reduce voids resulting from gas generated in a molded object, it has the problem that it is difficult to suppress voids generated by a different mechanism in a powder composition containing an inorganic reinforcing material. Patent Document 2 describes a method for producing a three-dimensional molded object using a highly heat-resistant resin such as a polyarylene sulfide resin, but does not mention inorganic reinforcing materials, only providing examples of fillers, and therefore has the problem that a three-dimensional molded object with excellent rigidity cannot be obtained.

[0008] Therefore, an object of the present invention is to provide a powder composition containing a polyarylene sulfide resin powder and an inorganic reinforcing material, which exhibits good mechanical properties even when residual powder used in three-dimensional modeling is recycled for modeling, and in particular, to provide a three-dimensional model that has excellent rigidity and heat resistance even when recycled for modeling.

[0009] In order to solve the above-mentioned problems and achieve the objects, the present invention has the following configurations: [1] A powder composition (C) containing a polyarylene sulfide resin powder (A) and an inorganic reinforcing material (B), wherein the polyarylene sulfide resin powder (A) has a number average particle size of 1 μm or more and 100 μm or less, the inorganic reinforcing material (B) has an average major axis diameter of 10 μm or more and 150 μm or less, the inorganic reinforcing material (B) accounts for 20 wt % or more and 60 wt % or less of the total weight of the powder composition (C), and the loss tangent of the powder composition (C) at a temperature 30° C. above the melting point of the polyarylene sulfide resin powder (A) contained in the powder composition (C) is 3 or more and 25 or less. [2] The powder composition according to [1], wherein the powder composition (C) is a mixture of a powder composition (c1) not subjected to a thermal load and a powder composition (c2) subjected to a thermal load, and the powder composition (c1) accounts for 10 wt % or more and 80 wt % or less of the total weight of the powder composition (C). [3] Yellowness b of the powder composition (c1) ０ * and the yellowness b* of the powder composition (C) is 1≦b*−b ０*≦20. [4] The powder composition according to [2], wherein the polyarylene sulfide resin powder (a1) contained in the powder composition (c1) has a melt flow rate of 70 g / 10 min or more and 200 g / 10 min or less. [5] The powder composition according to any one of [1] to [4], wherein a test piece having a width of 10 mm, a length of 80 mm, and a thickness of 4 mm is prepared by powder bed fusion, with the 80 mm length direction being parallel to the movement of a recoater (X direction), and the test piece has a flexural modulus in the X direction of 5000 MPa or more, as measured in accordance with JIS K7171 (2016), when the test piece is prepared with the 80 mm length direction being parallel to the lamination direction (Z direction), and a flexural modulus in the Z direction of 4000 MPa or more, as measured in accordance with JIS K7171 (2016). [6] The powder composition according to any one of [1] to [5], wherein the powder composition is a powder composition for producing a three-dimensional object by powder bed fusion. [7] A method for producing a three-dimensional object by powder bed fusion using the powder composition according to any one of [1] to [5]. [8] A three-dimensional object produced by powder bed fusion using the powder composition according to any one of [1] to [5]. [9] A three-dimensional object produced by X-ray CT measurement using a powder composition according to any one of [1] to [5]. ３ The volume observed within the field of view is 0.1 mm ３ [8] The three-dimensional structure according to [8], wherein the number of pores having a size equal to or larger than 400 is 400 or less.

[0010] According to the present invention, a powder composition containing a polyarylene sulfide resin powder and an inorganic reinforcing material can be obtained, which exhibits good mechanical properties even when residual powder used in three-dimensional modeling is recycled for modeling. Furthermore, a three-dimensional model having excellent rigidity, heat resistance, and high strength can be obtained even when recycled for modeling.

[0011] 1 is a schematic diagram showing an example of an apparatus for producing a three-dimensional object according to the present invention. 2 is a scanning electron microscope photograph of the powder composition obtained in Example 1.

[0012] The present invention will be described in detail below with reference to exemplary embodiments. Known methods for obtaining three-dimensionally shaped objects with excellent rigidity and heat resistance include using the aforementioned polyarylene sulfide resin as a material and incorporating an inorganic reinforcing material. However, when performing three-dimensional shaping using a powder composition containing a highly heat-resistant resin, the process involves melting the resin powder by irradiating it with a strong laser beam in a high-temperature environment near the melting point of the resin. This process causes the resin to change due to crosslinking or solid-state polymerization, making it difficult to maintain excellent rigidity and heat resistance even in recycling shaping. In response to this, the present inventors focused on the mechanisms of resin melting and inorganic reinforcing material impregnation in a powder composition during three-dimensional shaping, and discovered the dynamic viscoelastic properties necessary to obtain three-dimensionally shaped objects with excellent rigidity, heat resistance, and strength, thereby achieving the present invention.

[0013] The powder composition of the present invention will be described in detail below. The powder composition of the present invention contains a polyarylene sulfide resin powder (A). The polyarylene sulfide resin constituting the polyarylene sulfide resin powder (A) of the present invention is a homopolymer or copolymer having a repeating unit of the formula -(Ar-S)- as a main structural unit. Ar is a group containing an aromatic ring in which a bond is present on the aromatic ring, and examples thereof include divalent repeating units represented by the following formulas (1) to (11), among which the repeating unit represented by formula (1) is particularly preferred.

[0014]

[0015] (However, R in the formula １ , R ２ is a substituent selected from hydrogen, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and a halogen group; R １ and R ２ may be the same or different.)

[0016] Furthermore, the polyarylene sulfide resin in the present invention may be any of a random copolymer, a block copolymer, and a mixture thereof containing the above repeating unit. Representative examples thereof include polyphenylene sulfide resin, polyphenylene sulfide sulfone resin, polyphenylene sulfide ketone resin, and their random copolymers, block copolymers, and mixtures thereof. Particularly preferred polyarylene sulfide resins include polyphenylene sulfide resins, polyphenylene sulfide sulfone resins, and polyphenylene sulfide ketone resins containing 80 mol % or more, particularly 90 mol % or more, of p-phenylene sulfide units as the main structural unit of the polymer. Polyphenylene sulfide resins are most preferred.

[0017] In the present invention, the number average particle diameter of the polyarylene sulfide resin powder (A) contained in the powder composition is 1 μm or more and 100 μm or less. If the number average particle diameter exceeds 100 μm, the particle size becomes equal to or greater than the stacking height, which is undesirable because the surface of the molded product becomes rough. If the number average particle diameter is less than 1 μm, the particles are too fine and tend to adhere to the recoater during molding, making it difficult to raise the molding chamber temperature to the required level, which is undesirable. The upper limit of the number average particle diameter of the powder composition is more preferably 90 μm or less, even more preferably 80 μm or less, and particularly preferably 70 μm or less. The lower limit is more preferably 5 μm or more, even more preferably 20 μm or more, and particularly preferably 30 μm or more.

[0018] The number-average particle size of the polyarylene sulfide resin powder (A) is the arithmetic mean value of particle sizes of 100 particles of the polyarylene sulfide resin powder randomly selected from a photograph of the powder composition observed under a scanning electron microscope at a magnification of 100. When the fine particles are not perfectly circular in the image (for example, when they are elliptical or when the fine particles are irregularly gathered to form aggregates), the longest diameter is measured as the particle size.

[0019] The recrystallization temperature of the polyarylene sulfide resin powder (A) contained in the powder composition of the present invention is preferably 150°C or higher and 210°C or lower. If the recrystallization temperature of the polyarylene sulfide resin is lower than 150°C, solidification after laser light irradiation is significantly delayed, and a uniform powder surface cannot be formed when a powder layer is laminated on top of the molten resin. Furthermore, if the recrystallization temperature of the polyarylene sulfide resin exceeds 210°C, the molten polyarylene sulfide resin crystallizes upon laser light irradiation, causing shrinkage and warpage. The preferred lower limit of the recrystallization temperature is 150°C, more preferably 153°C, even more preferably 155°C, and particularly preferably 160°C. The preferred upper limit of the recrystallization temperature is 210°C, more preferably 205°C, even more preferably 200°C, and particularly preferably 195°C.

[0020] The melting point of the polyarylene sulfide resin powder (A) contained in the powder composition of the present invention is preferably 250°C or higher and 320°C or lower. If the melting point of the polyarylene sulfide resin is lower than 250°C, sufficient heat resistance cannot be obtained when the polyarylene sulfide resin is formed into a three-dimensional object. If the melting point of the polyarylene sulfide resin exceeds 320°C, it becomes necessary to increase the ambient temperature or the energy of the laser beam in order to sufficiently melt the polyarylene sulfide resin during laser beam irradiation, but this is not preferred because it results in significant thermal degradation of the polyarylene sulfide resin. The preferred lower limit of the melting point is 250°C, more preferably 255°C, even more preferably 260°C, and particularly preferably 265°C. The preferred upper limit of the melting point is 320°C, more preferably 310°C, even more preferably 305°C, and particularly preferably 300°C.

[0021] Here, the recrystallization temperature and melting point of the polyarylene sulfide resin powder (A) contained in the powder composition of the present invention are determined by measuring the powder composition in a nitrogen atmosphere using a differential scanning calorimeter, and the peak temperature of the endothermic peak during melting when the powder composition is heated from 50°C to 340°C at a rate of 20°C / min. The melting point of the polyarylene sulfide resin powder (A) is the peak temperature of the endothermic peak during melting, and then maintaining the powder composition at 340°C for 5 minutes and cooling it from 340°C to 50°C at a rate of 20°C / min. The recrystallization temperature of the polyarylene sulfide resin powder (A) is the peak temperature of the exothermic peak during crystallization when the powder composition is heated from 50°C to 340°C at a rate of 20°C / min.

[0022] The method for producing the polyarylene sulfide resin powder of the present invention is not particularly limited. The resin particles can be particles obtained by polymerization, or particles can be obtained from resins prepared in the form of pellets, fibers, or films. Furthermore, a pulverization process, as described below, can be performed depending on the form of the resin particles used. Other methods include a spray-drying method in which raw materials are dissolved in a solvent and then an emulsion is formed in a solvent and then contacted with a poor solvent, a submerged drying method in which an emulsion is formed in a solvent and then the organic solvent is dried and removed, and a forced melt kneading method in which a resin component to be granulated and another resin component are mechanically kneaded to form a sea-island structure, and then the sea component is removed with a solvent. Among these, pulverization is preferred from the standpoint of economy. The pulverization method is not particularly limited, and examples include a disk mill, a jet mill, a bead mill, a hammer mill, a ball mill, a sand mill, a turbo mill, and freeze-pulverization. Dry pulverization such as a turbo mill, a jet mill, and freeze-pulverization is preferred, with freeze-pulverization being more preferred.

[0023] The powder composition of the present invention contains 20% by mass or more and 60% by mass or less of an inorganic reinforcing material relative to the total weight of the powder composition. The upper limit of the blending amount is more preferably 55% by mass or less, even more preferably 50% by mass or less, and particularly preferably 45% by mass or less, in order to increase the storage modulus and make it difficult to achieve a loss tangent within the range of the present invention. The lower limit of the blending amount is more preferably 25% by mass or more, even more preferably 27% by mass or more, particularly preferably 29% by mass or more, and extremely preferably 31% by mass or more, in order to increase the rigidity of the three-dimensionally shaped object.

[0024] Examples of such inorganic reinforcing materials include glass fillers such as glass fiber, glass beads, glass flakes, and foamed glass beads; nepheline syenite fine powder, calcined clays such as montmorillonite and bentonite; clays (aluminum silicate powders) such as silane-modified clay; silicic acid-containing compounds such as talc, diatomaceous earth, and silica sand; crushed natural minerals such as pumice powder, pumice balloons, slate powder, and mica powder; minerals such as barium sulfate, lithopone, calcium sulfate, molybdenum disulfide, and graphite; silica (silicon dioxide) such as fused silica, crystalline silica, and amorphous silica; alumina (aluminum oxide); and colloidal alumina. Examples of suitable inorganic reinforcing materials include alumina (alumina sol), alumina white, and other aluminas; light calcium carbonate, heavy calcium carbonate, finely powdered calcium carbonate, and calcium carbonate fillers such as special calcium carbonate fillers; fly ash spheres; hollow volcanic glass bodies; synthetic inorganic hollow bodies; single-crystal potassium titanate; potassium titanate fibers; carbon fibers; carbon nanotubes; hollow carbon spheres; fullerenes; anthracite powder; cellulose nanofibers; artificial cryolite (cryolite); titanium oxide; magnesium oxide; basic magnesium carbonate; dolomite; calcium sulfite; mica; asbestos; calcium silicate; molybdenum sulfide; boron fibers; and silicon carbide fibers. Glass-based fillers, minerals, and carbon fibers are preferred due to their hardness and significant strength-enhancing effect, and glass-based fillers are even more preferred due to their narrow particle size and fiber size distributions. These inorganic reinforcing materials can be used alone or in combination of two or more.

[0025] Examples of glass-based fillers preferably used in the present invention include glass fibers, glass beads, glass flakes, and foamed glass beads. Glass fibers, glass beads, or mixtures thereof are more preferred because they can impart a high elastic modulus to the three-dimensionally shaped object. Among these, glass fibers are particularly preferred because they impart high strength to the three-dimensionally shaped object. Glass fibers may have either a circular or flat cross section.

[0026] The inorganic reinforcing material used in the present invention has an average major axis diameter of 10 μm or more and 150 μm or less. The upper limit is preferably 120 μm or less, even more preferably 100 μm or less, particularly preferably 70 μm or less, and extremely preferably 55 μm or less, because the crosslinking of the polyarylene sulfide resin increases viscosity, particularly during recycling molding, and the larger the average major axis diameter of the inorganic reinforcing material, the lower the impregnation ability into the molten polyarylene sulfide resin decreases, making voids more likely to occur in the three-dimensionally shaped object. The lower limit is more preferably 15 μm or more, even more preferably 20 μm, particularly preferably 25 μm or more, and extremely preferably 30 μm or more, because the strength of the three-dimensionally shaped object is improved.

[0027] The shape factor of the inorganic reinforcing material preferably used in the present invention is expressed as the average major axis diameter / average minor axis diameter, and is preferably 2 or more and 12 or less. The upper limit is more preferably 10 or less, even more preferably 8 or less, particularly preferably 7 or less, and extremely preferably 6 or less, in order to achieve significant orientation in the X direction and increase anisotropy. The lower limit is more preferably 2.5 or more, particularly preferably 3 or more, in order to improve the strength of the three-dimensionally shaped object.

[0028] In the present invention, the average major axis diameter and the average minor axis diameter of the inorganic reinforcing material are the number average values ​​of the major axis diameter and the minor axis diameter of 100 inorganic reinforcing material particles randomly selected from a photograph obtained by photographing the powder composition with a scanning electron microscope. The major axis diameter is the diameter at which the distance between two parallel lines is the largest when the particle image is sandwiched between two parallel lines in a direction perpendicular to the major axis, and the minor axis diameter is the diameter at which the distance between two parallel lines is the smallest when the particle image is sandwiched between two parallel lines in a direction perpendicular to the major axis.

[0029] In the present invention, the loss tangent of powder composition (C) at a temperature 30°C above the melting point of the polyarylene sulfide resin powder (A) contained in powder composition (C) is 3 or more and 25 or less. A loss tangent of less than 3 is undesirable because the elasticity term has a greater effect than the viscosity term, causing resistance to the polyarylene sulfide resin melting during laser irradiation and the impregnation and homogenization of the inorganic reinforcing material, resulting in floating edges of the three-dimensionally molded object and the remaining voids in the three-dimensionally molded object, thereby reducing the quality and rigidity of the three-dimensionally molded object. Furthermore, a loss tangent of more than 25 is undesirable because crosslinking of the polyarylene sulfide resin due to heat load during the three-dimensional molding process is insufficient, resulting in unstable quality during recycled molding. Furthermore, it has been surprisingly discovered that a loss tangent of powder composition (C) of 25 or less increases the toughness of the resulting three-dimensionally molded object, achieving both high rigidity and high strength. The lower limit of the loss tangent of the powder composition is preferably 3.5 or more, more preferably 4 or more, and particularly preferably 5 or more. The upper limit is more preferably 20 or less, still more preferably 15 or less, and particularly preferably 10 or less.

[0030] The loss tangent of the powder composition is measured in a nitrogen atmosphere using a viscoelasticity measuring device with parallel plates at a gap of 1 mm, an oscillation angle of 100%, and a frequency of 0.5 Hz, and the loss tangent is calculated as the loss modulus / storage modulus with respect to the measured storage modulus and loss modulus, particularly the loss tangent value at the melting point of the polyarylene sulfide resin powder (A) + 30°C. The measurement was performed at a temperature condition of from the melting point of the polyarylene sulfide resin powder (A) + 10°C to the melting point of the polyarylene sulfide resin powder (A) + 40°C at a rate of 5°C / min. The melting point of the polyarylene sulfide resin powder (A) is determined as the apex temperature of the endothermic peak during melting when the powder composition is heated from 50°C to 340°C at a rate of 20°C / min using a differential scanning calorimeter in a nitrogen atmosphere.

[0031] In the present invention, in order to obtain a powder composition having a loss tangent within a predetermined range, methods include reducing the amount of inorganic reinforcing material to decrease the storage modulus, using an inorganic reinforcing material with a short average major axis diameter to decrease the resistance between the molten resin and the inorganic reinforcing material, increasing the amount of powder composition (c1) having a large loss tangent relative to the total weight of powder composition (C), and increasing the melt flow rate of polyarylene sulfide resin powder (a1) contained in powder composition (c1).

[0032] The powder composition (C) of the present invention is preferably a mixture of a powder composition (c1) that has not been subjected to a thermal load and a powder composition (c2) that has been subjected to a thermal load. Here, the thermal load can be caused by prolonged exposure to temperatures above the recrystallization temperature and below the melting point of the polyarylene sulfide resin in the three-dimensional modeling process, or by aging treatment using a dryer or oven. However, the thermal load is more preferably caused by the three-dimensional modeling process, since it is preferable to reuse the remaining powder in the recycling modeling process to reduce waste powder. Details regarding the three-dimensional modeling process will be described later. The thermal load in the powder composition (c2) that has been subjected to a thermal load is more preferably exposed to a temperature above the recrystallization temperature and below the melting point in the three-dimensional modeling process for 10 hours or more, since it allows the production of large three-dimensional objects, such as three-dimensional models for final products. The powder composition (c2) that has been subjected to a thermal load by repeating the mixing to produce the powder composition (C) and recycling modeling three or more times is particularly preferred, since the modification of the polyarylene sulfide resin due to the thermal load is saturated. Regarding the temperature of the heat load, the bottom and sides of the tank in which the three-dimensional object is formed are generally set to a temperature slightly higher than the recrystallization temperature, and the powder surface on which the three-dimensional object is formed is set to a temperature slightly lower than the melting point, and the powder is generally exposed to temperatures above the recrystallization temperature and below the melting point during the three-dimensional object forming process.

[0033] In the present invention, the powder composition (c1) is preferably contained in an amount of 10% by weight or more and 80% by weight or less relative to the total weight of the powder composition (C). In powder bed fusion (PBF) processes, the majority of the powder used does not become the molded object but is recovered as residual powder. This residual powder is preferably used as the thermally loaded powder composition (c2). Because a portion of the powder composition used in three-dimensional modeling becomes the three-dimensional object, a powder composition (c1) content of 10% by weight or more relative to the total weight of the powder composition (C) is preferred, as this maintains mass balance and allows for stable three-dimensional modeling. Furthermore, since at least 20% by weight of the residual powder that becomes the thermally loaded powder composition (c2) is generally recovered, the powder composition (c1) content is preferably 80% by weight or less. Therefore, the lower limit of the powder composition (c1) content is more preferably 15% by weight or more, even more preferably 20% by weight or more. In order to obtain three-dimensional models with stable and excellent rigidity, a content of 25% by weight or more is particularly preferred, and 30% by weight or more is particularly preferred. The upper limit is more preferably 70% by weight or less, even more preferably 65% ​​by weight or less, and is particularly preferably 60% by weight or less, and most preferably 55% by weight or less, in view of excellent recyclability and reduction of waste powder.

[0034] The yellowness of the powder composition (c1) of the present invention is ０ *, where b* is the yellowness of the powder composition (C), 1≦b*−b ０ It is preferable that the relationship b*≦20 holds. The polyarylene sulfide resin contained in the powder composition of the present invention tends to become more yellowish in the three-dimensional fabrication process using powder bed fusion. ０ By performing three-dimensional modeling using a powder composition (C) in which * is 1 or more, a three-dimensional model with a stable yellow color can be obtained, which is preferable. In addition, the difference in yellow color between the powder composition (c1) not subjected to a thermal load and the powder composition (C) mixed with it to be used for the three-dimensional model, b* - b ０ If * is greater than 20, the powder properties within the powder composition (C) vary greatly, which is undesirable as it can cause the rigidity and quality of the resulting three-dimensionally shaped object to deteriorate. ０The lower limit of * is more preferably 2 or more, even more preferably 3 or more, and particularly preferably 4 or more. The upper limit is more preferably 17 or less, even more preferably 15 or less, and particularly preferably 13 or less.

[0035] In the present invention, the yellowish color b ０ * and b* are the b* values ​​measured by placing approximately 5 g of powder in a quartz cell with a diameter of 35 mm and using a spectrophotometer (SE2000) manufactured by Nippon Denshoku Industries Co., Ltd., as described in JIS Z8722 (2009) and Z8781 (2013).

[0036] The melt flow rate of the polyarylene sulfide resin powder (a1) contained in the powder composition (c1) of the present invention is preferably 70 g / 10 min or more and 200 g / 10 min or less. A melt flow rate of 70 g / 10 min or more of the polyarylene sulfide resin powder (a1) can improve the impregnation of inorganic reinforcing materials even during recycling molding, and a melt flow rate of 200 g / 10 min or less is preferable because the molten polyarylene sulfide resin retains its shape and a high-quality three-dimensional molded object can be obtained. The lower limit of the melt flow rate of the polyarylene sulfide resin powder (a1) is more preferably 75 g / 10 min or more, and even more preferably 80 g / 10 min or more. The upper limit is more preferably 170 g / 10 min or less, and even more preferably 150 g / 10 min or less.

[0037] The melt flow rate of the polyarylene sulfide resin powder (a1) is a value measured under conditions of 315.5° C. and a load of 5 kg in accordance with a method in accordance with ASTM-D1238-70.

[0038] The weight average molecular weight of the polyarylene sulfide resin powder (a1) contained in the powder composition (c1) of the present invention is not particularly limited as long as it is a weight average molecular weight that results in the desired loss tangent when made into the powder composition (C), but in order to obtain better mechanical properties, the weight average molecular weight is preferably 30,000 to 150,000, more preferably 40,000 to 120,000, and even more preferably 45,000 to 100,000. If the weight average molecular weight is small, the mechanical properties of the polyarylene sulfide resin itself will deteriorate, so a weight average molecular weight of 30,000 or more is preferred. On the other hand, if the weight average molecular weight exceeds 150,000, the melt viscosity will increase significantly, which tends to be undesirable for three-dimensional modeling.

[0039] The weight average molecular weight in the present invention is a value calculated in terms of polystyrene using gel permeation chromatography (GPC) manufactured by Senshu Scientific Co., Ltd.

[0040] To the extent that the effects of the present invention are not impaired, the powder composition preferably contains a flow aid to improve fluidity. A flow aid refers to a substance that suppresses powder aggregation due to adhesive forces between powders. The inclusion of such a flow aid can improve the fluidity of the powder composition, reducing defects that can cause deterioration of mechanical properties and tending to further improve the appearance of the resulting shaped product.

[0041] Examples of such flow aids include silica (silicon dioxide) such as fused silica, crystalline silica, and amorphous silica; alumina (aluminum oxide), alumina colloid (alumina sol), and alumina white; calcium carbonate such as light calcium carbonate, heavy calcium carbonate, finely powdered calcium carbonate, and special calcium carbonate-based fillers; titanium oxide, magnesium oxide, basic magnesium carbonate, potassium titanate fiber, boron fiber, silicon carbide fiber, and carbon black. Silica, alumina, calcium carbonate powder, titanium oxide, and carbon black are particularly preferred. Silica is particularly preferred because it is hard and can contribute to improving strength and flowability. Among these, amorphous silica particles, which are less harmful to the human body, are industrially extremely preferred.

[0042] The D50 particle size of such a flow aid is preferably 20 nm or more and 3000 nm or less. The upper limit of the D50 particle size of the flow aid is more preferably 2000 nm, even more preferably 1000 nm, particularly preferably 500 nm, extremely preferably 300 nm, and most preferably 200 nm. The lower limit is more preferably 30 nm, even more preferably 50 nm, particularly preferably 100 nm, extremely preferably 120 nm, and most preferably 140 nm. If the D50 particle size of the flow aid is within the above range, the fluidity of the powder composition is improved and the flow aid tends to be uniformly dispersed in the powder composition.

[0043] The blending amount of such flow aid is preferably 0.01% by mass or more and 2.0% by mass or less, based on the total weight of the polymer powder composition. The upper limit of the blending amount is more preferably 1.5% by mass or less, even more preferably 1.0% by mass or less, particularly preferably 0.8% by mass or less, and extremely preferably 0.7% by mass or less. The lower limit of the blending amount is more preferably 0.02% by mass or more, even more preferably 0.03% by mass or more, and particularly preferably 0.04% by mass or more. When the blending amount of the flow aid is equal to or greater than the above-mentioned lower limit, the fluidity of the polymer powder composition is further improved, and the filling ability when shaped is increased. Therefore, voids that cause defects in mechanical properties are less likely to occur, and the resulting shaped product tends to exhibit high strength. When the blending amount of the flow aid is equal to or less than the above-mentioned upper limit, sintering is not inhibited due to the flow aid coating the surfaces of the polymer particles, and shaped products with high strength tend to be obtained.

[0044] It is important that the powder composition (C) of the present invention is a uniform mixture of the polyarylene sulfide resin powder (A) and the inorganic reinforcing material (B), and the powder composition (c1) and the powder composition (c2). While the mixing method is not particularly limited, a mixing method in which the container containing the polyarylene sulfide resin powder and the inorganic reinforcing material is rotated is preferred in terms of mixture recovery and use. The rotation axis of the container is not particularly specified, but one with two or more rotation axes is preferred. The rotation speed of the mixing container is preferably 3.5 rpm or more and 35 rpm or less, more preferably 15 rpm or more and 30 rpm or less, regardless of the rotation direction. The longer the mixing time, the more effective it is for uniform mixing; 15 minutes or more is preferred, and 20 minutes or more is more preferred.

[0045] In the present invention, when a fibrous inorganic reinforcing material is used, it is preferable to use a container equipped with a stirring blade or rotary blade inside. Using these eliminates fiber aggregation and enables more uniform mixing. It is preferable that one or more rotary blades or stirring blades are equipped per container. The rotation speed of the rotary blade is preferably 100 rpm or more and 1,000 rpm or less, more preferably 400 rpm or more and 700 rpm or less.

[0046] Powder bed fusion is a suitable method for creating the three-dimensional object of the present invention. Powder bed fusion is a 3D printing technique that produces a three-dimensional object by forming a layer of raw material resin particles, melting and welding the layer using a heat source at a position corresponding to the cross section of the desired object, and then forming an additional layer of thermoplastic resin particles on top of the layer, repeating this process.

[0047] The three-dimensional fabrication process using the powder bed fusion method of the present invention will be described below with reference to FIG.

[0048] In the first step, the stage 2 of the tank 1 in which the object is formed is lowered.

[0049] In the second step, the stage 4 of the tank 3 (hereinafter sometimes referred to as the supply tank), which has been previously filled with the material powder P to be supplied to the tank 1 where the molded object is formed, is raised to a height that allows for the supply of a sufficient amount of material powder P to fill the tank 1 with the specified layer height. Then, the recoater 5 is moved from the left end of the supply tank 3 to the right end of the tank 1, and the material powder P is layered 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 material powder P is the Y direction. Reference numeral 7 denotes a coordinate system representing the X direction, Y direction, and Z direction. Reference numeral 8 denotes the surface direction in which the material powder is layered, and reference numeral 9 denotes the height direction in which the material powder is layered.

[0050] In the third step, the material powder P filled into the tank 1 to a predetermined stack height in the second step is subjected to thermal energy 6 capable of melting, thereby selectively melting and sintering the material powder P in accordance with the molding data. Examples of selective melting and sintering methods include selective laser sintering, in which a laser is irradiated onto a shape corresponding to the cross-sectional shape of the object to be molded, thereby bonding the powder composition. Other examples include a printing process in which an energy absorption promoter or an energy absorption inhibitor is printed onto a shape corresponding to the cross-sectional shape of the object to be molded, and a selective absorption (or suppression) sintering process in which electromagnetic radiation is used to bond resin powder.

[0051] In the powder bed fusion method, the first to third steps are repeated to obtain a three-dimensional structure 10, and the material powder that has been subjected to a thermal load at a temperature between the crystallization temperature and the melting point remains in the tank 1. In the present invention, this remaining material powder that has been subjected to the thermal load can be used as the powder composition (c2).

[0052] The method for producing a three-dimensional object of the present invention is a method for producing a three-dimensional object by powder bed fusion using the powder composition of the present invention. As a method for producing a three-dimensional object by powder bed fusion, a known method can be used, for example, the method described in International Publication No. WO 2022-250003.

[0053] The three-dimensional object of the present invention is a three-dimensional object obtained by powder bed fusion using powder composition (C) such that when a test piece having a width of 10 mm, a length of 80 mm, and a thickness of 4 mm is prepared by powder bed fusion such that the 80 mm length direction is parallel to the direction of movement of a recoater (X direction), the test piece has a flexural modulus in the X direction of 5000 MPa or more, as measured in accordance with JIS K7171 (2016), and when the 80 mm length direction is parallel to the stacking direction (Z direction), the test piece has a flexural modulus in the Z direction of 4000 MPa or more.

[0054] The flexural modulus in the X direction of the three-dimensionally shaped object of the present invention is preferably 5,500 MPa or more, more preferably 6,000 MPa or more, even more preferably 6,500 MPa or more, and particularly preferably 7,000 MPa or more, in order to provide a three-dimensionally shaped object with high rigidity and resistance to deformation when used in final products. Although there are no particular upper limits, an excessively high modulus generally tends to make the object brittle and reduce its strength, so the upper limit is preferably 20,000 MPa or less, more preferably 17,000 MPa or less, even more preferably 15,000 MPa or less, and particularly preferably 12,000 MPa or less.

[0055] The bending strength in the X direction of the three-dimensionally shaped object of the present invention is the strength capable of withstanding the force from the direction in which the greatest stress is applied, and is preferably 100 MPa or more. In the present invention, it has been surprisingly discovered that when the loss tangent of the powder composition (C) used for three-dimensional shaping is 25 or less at a temperature 30°C above the melting point of the polyarylene sulfide resin powder (A) contained in the powder composition (C), the toughness of the resulting three-dimensionally shaped object is increased, achieving both high rigidity and high strength. The bending strength in the X direction is more preferably 105 MPa or more, even more preferably 110 MPa or more, and particularly preferably 112 MPa or more.

[0056] The flexural modulus in the Z direction of the three-dimensionally shaped object of the present invention is preferably 4200 MPa or more, more preferably 4500 MPa or more, even more preferably 4700 MPa or more, and particularly preferably 5000 MPa or more, in order to achieve high rigidity even in the direction in which the elastic modulus of the three-dimensionally shaped object is lowest when used in final product applications. Although there are no particular limitations on the upper limit, since an excessively high elastic modulus generally leads to brittleness and low strength, the upper limit is preferably 15000 MPa or less, more preferably 13000 MPa or less, even more preferably 11000 MPa or less, and particularly preferably 10000 MPa or less.

[0057] The bending strength in the Z direction of the three-dimensionally shaped object of the present invention is the strength in the direction in which the three-dimensionally shaped object is weakest, and is preferably 55 MPa or more, more preferably 58 MPa or more, even more preferably 60 MPa or more, and particularly preferably 62 MPa or more, in order to increase the lower limit of the design strength when using the three-dimensionally shaped object as a final product.

[0058] In the present invention, the flexural modulus and flexural strength can be measured by a three-point bending test in accordance with JIS K7171 (2016), with a support distance of 64 mm and a test speed of 2 mm / min. The measurement temperature is room temperature (23°C), the number of measurements is n = 10, and the average values ​​are taken as the flexural modulus and flexural strength.

[0059] The deflection temperature under load of the three-dimensionally shaped object of the present invention is preferably 190° C. or higher. The higher the deflection temperature under load, the less likely the shaped object is to deform in a high-temperature environment. Therefore, the deflection temperature under load of the shaped object is more preferably 200° C. or higher, even more preferably 210° C. or higher, particularly preferably 220° C. or higher, significantly more preferably 230° C. or higher, and most preferably 240° C. or higher.

[0060] In the present invention, the deflection temperature under load is a value measured on a test piece having a width of 10 mm, a length of 80 mm, and a thickness of 4 mm, prepared by powder bed fusion bonding so that the 80 mm length direction is parallel to the direction of movement of a recoater (X direction), in accordance with Japanese Industrial Standards (JIS) JIS K7191-1 (2015) "Plastics - Determination of deflection temperature under load." The value is measured under a load of 1.8 MPa.

[0061] The three-dimensionally shaped object of the present invention preferably has a yellowness of 5 to 50 when the lightness is 60 or more, and 1 to 20 when the lightness is less than 60. The three-dimensionally shaped object of the present invention is characterized by being a three-dimensionally shaped object made using a powder composition that has been repeatedly recycled in a three-dimensional shaping process using powder bed fusion. This enables the object to have consistent quality in color, both within the same three-dimensionally shaped object and between different three-dimensionally shaped objects. Therefore, when the lightness is 60 or more, the lower limit of the yellowness is preferably 6 or more, more preferably 8 or more, even more preferably 10 or more, and particularly preferably 12 or more. The upper limit is preferably 40 or less, more preferably 30 or less, even more preferably 25 or less, and particularly preferably 20 or less. When the lightness is less than 60, the lower limit of the yellowness is preferably 1.5 or more, more preferably 2 or more, even more preferably 2.5 or more, and particularly preferably 3 or more. The upper limit is preferably 15 or less, more preferably 10 or less, even more preferably 7 or less, and particularly preferably 5 or less.

[0062] The yellowness of the three-dimensionally shaped object of the present invention is the b* value measured on a flat surface of the three-dimensionally shaped object using a spectrophotometer (SE2000) manufactured by Nippon Denshoku Industries Co., Ltd., as described in JIS Z8722 (2009) and Z8781 (2013).

[0063] Furthermore, in three-dimensional modeling, a powder is filled into a molded object through melt sintering under normal pressure, which usually involves density changes due to shrinkage. Therefore, in order to obtain highly accurate dimensions of the three-dimensional object based on the desired modeling data, it is preferable for the object to have a moderate amount of voids inside. The proportion and shape of voids present in the three-dimensional object of the present invention can be observed using X-ray CT.

[0064] The three-dimensional object of the present invention is imaged by X-ray CT, and the ratio of the portions observed as voids to the volume of the entire object can be expressed as the porosity. The porosity observed by X-ray CT measurement of the three-dimensional object of the present invention is preferably 0.1 vol% or more and 10 vol% or less. The lower limit of the porosity is more preferably 0.2 vol% or more, even more preferably 0.3 vol% or more, and particularly preferably 0.5 vol% or more, because a too small porosity can cause the entire object to shrink relative to the modeling data. Furthermore, the upper limit is more preferably 5.0 vol% or less, even more preferably 4.0 vol% or less, and particularly preferably 3.0 vol% or less, because a large number of voids can cause a decrease in strength.

[0065] The size of each independent pore observed as a void when the three-dimensionally shaped object of the present invention is imaged by X-ray CT can be expressed as a sphere-equivalent diameter. The average sphere-equivalent diameter of the voids observed by X-ray CT measurement of the three-dimensionally shaped object of the present invention is preferably 1 μm or more and 100 μm or less. In the case of melt molding that does not involve a three-dimensional shaping process, the average sphere-equivalent diameter of the voids is usually designed to be less than 1 μm. In cases where voids are intentionally formed, such as in foam molding, the average sphere-equivalent diameter of the voids is usually greater than 100 μm. As described above, a certain amount of voids are generated during three-dimensional shaping under normal pressure, so the lower limit is preferably 3 μm or more, more preferably 5 μm or more, and even more preferably 10 μm or more. The upper limit is preferably 80 μm or less, more preferably 60 μm or less, and even more preferably 50 μm or less, because large voids become defects and cause a decrease in the strength of the shaped object.

[0066] The three-dimensional object of the present invention is photographed by X-ray CT and ３ When the field of view is extracted and analyzed, the voids observed have a volume of 0.1 mm ３ It is preferable that the number of voids having a size of 0.1 mm or more is 400 or less. Even in the method for obtaining a three-dimensionally shaped object having high rigidity and heat resistance and stable quality in recycle shaping by using the powder composition and the method for producing a three-dimensionally shaped object of the present invention, it is surprising that the number of voids having a volume of 0.1 mm or less generated in the three-dimensionally shaped object is 0.1 mm or less. ３It has been found that the number of pores having a size of 0.1 mm or more can be reduced to 400 or less. In particular, in a powder composition capable of exhibiting high rigidity, the number of pores having a size of 0.1 mm or more can be reduced to 400 or less due to the relationship between the molten resin and the impregnation of the inorganic reinforcing material. ３ It was found that voids with a volume of 0.1 mm or more were likely to occur, which impairs the rigidity, strength, and quality stability of the three-dimensionally shaped object. As a result of extensive research by the present inventors, this was achieved for the first time by using the powder composition and the method for manufacturing a three-dimensionally shaped object of the present invention. ３ The number of pores having the above size is more preferably 300 or less, even more preferably 270 or less, particularly preferably 250 or less, and most preferably 230 or less. The lower limit is 0.

[0067] In the present invention, the porosity of the three-dimensional object, the average equivalent spherical diameter of the pores, and the volume of the pores (0.1 mm ３ The number of pores having the above size was determined by imaging a three-dimensional object with an accuracy of 5 μm pixel size by X-ray CT observation, and dividing the observed image into 40 mm ３ The pores were extracted within a field of view of 100 mm, and the pores were labeled. The diameter of each individual pore was calculated as a sphere, and the average value was calculated as the average sphere-equivalent diameter of the pores. The volume of the pores labeled as above was divided by the total volume of the pores filled in the part corresponding to the object in the observation image, and the result was multiplied by 100 to obtain the porosity. In addition, the porosity of a pore with a volume of 0.1 mm was calculated as follows: ３ The number of pores having the above size was calculated.

[0068] Compared to conventional melt molding, three-dimensional objects are obtained by crystallization in a process of slowly lowering the temperature at normal pressure, and therefore the state of the crystals differs from that of conventional melt molding. However, it is difficult to express this as a characteristic of the object, and therefore they are specified by the manufacturing method, i.e., three-dimensional objects obtained by three-dimensional molding, preferably powder bed fusion. It is well known that conventional melt molding can produce molded objects with excellent rigidity and heat resistance through careful consideration by those skilled in the art, in accordance with the structure of the mold. However, in three-dimensional molding, which is capable of molding complex shapes, it has not been possible to obtain molded objects with excellent rigidity and heat resistance, especially in recycling molding of residual powder used in three-dimensional molding. This has only been made possible by the present invention.

[0069] The present invention will be described in more detail below with reference to examples, although the present invention is not limited to these examples.

[0070] [Measurement and Evaluation Methods] (1) Number Average Particle Diameter of Polyarylene Sulfide Resin Powder (A) The powder composition was observed at a magnification of 100 times using a scanning electron microscope (JSM-IT700HR) manufactured by JEOL Ltd., and the arithmetic mean value of particle diameters of 100 particles of polyarylene sulfide resin powder randomly selected from the photograph was taken as the number average particle diameter.

[0071] (2) Average major axis diameter of inorganic reinforcing material (B) The powder composition was observed at a magnification of 100 times using a scanning electron microscope (JSM-IT700HR) manufactured by JEOL Ltd., and the arithmetic mean value of the major axis diameters of 100 inorganic reinforcing materials randomly selected from the photograph was taken as the average major axis diameter.

[0072] (3) Melting Point of Polyarylene Sulfide Resin Powder (A) The powder composition was measured using a differential scanning calorimeter (DSCQ20) manufactured by TA Instruments Co., Ltd., where the temperature was increased from 30°C to 340°C at a rate of 20°C / min under a nitrogen atmosphere. The apex temperature of the endothermic peak during melting was determined as the melting point of the polyarylene sulfide resin powder (A). The sample required for the measurement was about 8 mg.

[0073] (4) Melt Flow Rate of Polyarylene Sulfide Resin Powder (a1) The melt flow rate of the polyarylene sulfide resin powder (a1) was measured using the polyarylene sulfide resin powder as a sample under conditions of 315.5°C and a load of 5 kg in accordance with a method in accordance with ASTM-D1238-70.

[0074] (5) The loss tangent of the powder composition (C) at the melting point of the polyarylene sulfide resin powder (A) + 30°C was measured using an MCR501 manufactured by Anton Paar, with parallel plates of 25 mm diameter and a gap of 1 mm, in a nitrogen atmosphere, with an oscillation angle of 100%, a frequency of 0.5 Hz, and a temperature range of 300°C to 330°C, while increasing the temperature at a rate of 5°C / min. Regarding the measured storage modulus and loss modulus, the loss tangent calculated by the loss modulus / storage modulus is particularly the value of the loss tangent at the melting point of the polyarylene sulfide resin powder (A) + 30°C.

[0075] (6) Yellowness of Powder Composition (C) The yellowness of the powder composition (C) was measured using a spectrophotometer (SE2000) manufactured by Nippon Denshoku Industries Co., Ltd. Approximately 5 g of the powder composition was placed in a dedicated colorless and transparent quartz dish, and the dish was tightly packed while being vibrated, and then the measurement was performed.

[0076] (7) Quality of three-dimensionally molded objects The quality of three-dimensionally molded objects was evaluated using the following criteria: five test pieces measuring 10 mm in width, 80 mm in length, and 4 mm in thickness were produced using a powder bed fusion 3D printer (RaFaElII 300-HT) manufactured by Aspect Co., Ltd., with the 80 mm length direction being the Z direction. ◯: No voids or chips were observed visually in any of the objects, and no irregularities were observed on the 10 mm wide x 80 mm long surface. △: Some of the objects had slight voids or chips observed visually. Some had slight irregularities on the 10 mm wide x 80 mm long surface. ×: Voids and chips were observed visually. All test pieces had obvious irregularities on the 10 mm wide x 80 mm long surface.

[0077] (8) Measurement of flexural modulus and flexural strength of three-dimensionally molded objects The flexural modulus and flexural strength of three-dimensionally molded objects were measured using a powder bed fusion 3D printer (RaFaElII 300-HT) manufactured by Aspect Co., Ltd. A test piece with a width of 10 mm, a length of 80 mm, and a thickness of 4 mm was prepared so that the 80 mm length was in the X direction or Z direction, and the flexural modulus in the X direction and Z direction was measured using a Tensilon universal testing machine (TENSIRON TRG-1250) manufactured by A & D Co., Ltd. In accordance with JIS K7171 (2016), a three-point bending test was performed under conditions of a support distance of 64 mm and a test speed of 2 mm / min to determine the flexural modulus and flexural strength. The measurement temperature was room temperature (23 ° C), the number of measurements was n = 10, and the average value was calculated.

[0078] (9) Measurement of the load deflection temperature of a three-dimensionally molded object The load deflection temperature of a three-dimensionally molded object was measured using a powder bed fusion 3D printer (RaFaElII 300-HT) manufactured by Aspect Co., Ltd. A test piece 10 mm wide, 80 mm long, and 4 mm thick was prepared so that the 80 mm length direction was the X direction, and a heat distortion tester (No. 148) manufactured by Yasuda Seiki Seisakusho Co., Ltd. was used. The number of measurements was n = 3, and the average value was calculated.

[0079] (10) Measurement of yellowness of three-dimensionally shaped object A test piece having a width of 10 mm, a length of 80 mm, and a thickness of 4 mm was prepared using a powder bed fusion type 3D printer (RaFaElII 300-HT) manufactured by Aspect Co., Ltd. The b * value of this test piece was measured with n = 3 using a spectrophotometer (SE2000) manufactured by Nippon Denshoku Industries Co., Ltd., and the arithmetic mean value was calculated.

[0080] (11) Measurement of voids in three-dimensional objects Using an X-ray CT device (Xradia 510 Versa) manufactured by ZEISS, three-dimensional transmission image observation was performed at a resolution of 5 μm, a field of view of 5 mm, a voltage of 80 kV, and a power of 7 W. The observed image was recorded on a 40 mm ３ The pores were extracted within the field of view, and the pores were labeled. The volume of each individual pore was calculated, and the volume was determined to be 0.1 mm. ３ The number of pores having a size equal to or larger than this was calculated.

[0081] [Production Example 1] A 1-liter autoclave equipped with a stirrer was charged with 1.00 mol of 47 wt% sodium hydrosulfide, 1.05 mol of 46 wt% sodium hydroxide, 1.65 mol of N-methyl-2-pyrrolidone (NMP), 0.45 mol of sodium acetate, and 5.55 mol of ion-exchanged water, and the mixture was gradually heated to 225°C over about 2 hours under atmospheric pressure while passing nitrogen through it. After distilling off 11.70 mol of water and 0.02 mol of NMP, the reaction vessel was cooled to 160°C.

[0082] Next, 1.02 mol of p-dichlorobenzene (p-DCB) and 1.32 mol of NMP were added, and the reaction vessel was sealed under nitrogen gas. While stirring at 400 rpm, the temperature was raised in two stages, from 160°C to 240°C at a rate of 0.4°C / min and from 240°C to 270°C at a rate of 0.4°C / min. 10 minutes after reaching 270°C, 0.75 mol of water was injected into the system over 15 minutes. After 120 minutes at 270°C, the system was cooled to 200°C at a rate of 1.0°C / min, and then rapidly cooled to near room temperature, and the contents were removed.

[0083] The contents were taken out and diluted with 0.5 liters of NMP, and then the solvent and solid matter were separated by filtration using a sieve (80 mesh). The obtained solid matter was washed several times with 1 liter of warm water, and then washed with 800 g of calcium acetate monohydrate in an amount of 0.45% by weight based on the weight of the solid polyarylene sulfide, and further washed with 1 liter of warm water and separated by filtration to obtain a cake.

[0084] The obtained cake was dried at 120°C under a nitrogen stream and then pulverized to obtain a polyarylene sulfide resin powder having an amount of gas generated of 0.34 wt%, a melt flow rate of 150 g / 10 min, a weight average molecular weight of 54,000, a number average particle size of 43 μm, a melting point of 294°C, and a recrystallization temperature of 178°C.

[0085] Comparative Example 1 13 kg of the polyarylene sulfide resin powder obtained in Production Example 1, 7 kg of glass fiber EPG40M-01N (manufactured by Nippon Electric Glass Co., Ltd., average major axis diameter 43 μm) as an inorganic reinforcing material, and 40 g of trimethylsilylated amorphous silica QSG-170 (manufactured by Shin-Etsu Chemical Co., Ltd., D50 particle size 170 nm) as a flow aid were added and mixed while rotating and revolving using a cross rotary mixer under conditions of nitrogen atmosphere, room temperature, and normal pressure to obtain powder composition (c1). The melting point of this powder composition (c1) measured with a differential scanning calorimeter was 296°C. The loss tangent of this powder composition (c1) at 324°C was 35, and a yellowish b ０ * was 4.0. Using 20 kg of this powder composition (c1), a three-dimensional object was manufactured using a powder bed fusion machine (RaFaElII 300-HT) manufactured by Aspect Corporation. The powder surface temperature in tank 1 was 260°C, the side temperature was 200°C, the bottom temperature was 200°C, and the Z-direction depth was 180 mm. The thermal load during manufacturing was approximately 15 hours. Both the obtained X-direction bending test specimens and Z-direction bending test specimens were free of defects or irregularities and were of excellent quality. The brightness of the obtained three-dimensional object was 66, and the yellowness was 21. The flexural modulus in the X-direction was 6800 MPa, the flexural strength was 92 MPa, and the flexural modulus in the Z-direction was 5200 MPa, and the flexural strength was 53 MPa. The deflection temperature under load at 1.8 MPa was 240°C. X-ray CT observation was performed on this bending test piece in the X direction, and it was found that the porosity was 3.2% by volume, the sphere-equivalent diameter of the pores was 28 μm, and the volume was 0.1 mm ３ The number of voids having the above size was 134. Table 1 shows the powder composition (C) used and the three-dimensional shaped article obtained.

[0086] [Example 1] The powder remaining in tank 1 of the three-dimensional modeling apparatus in Comparative Example 1 was recovered, and 10 kg of this remaining powder was blended with 10 kg of powder composition (c1). The blended powder was mixed under nitrogen atmosphere, room temperature, and normal pressure conditions, while rotating and revolving using a cross rotary mixer. Similarly, three-dimensional modeling was performed to a depth of 180 mm. This constitutes the first recycling modeling. This recycling modeling was repeated twice, and 10 kg of powder composition (c2), which had been subjected to a thermal load of approximately 15 hours of three-dimensional modeling three times while blending 50 wt% of powder composition (c1), was blended with 10 kg of powder composition (c1), and mixed in the same manner to obtain powder composition (C). The melting point of this powder composition (C) measured using a differential scanning calorimeter was 296°C. The loss tangent of powder composition (C) at 326°C was 6.4. The yellowish b of powder composition (c1) ０ * is 4.0, the yellowness b* of powder composition (C) is 12.8, and b*-b ０ *=8.8. A photograph of the obtained powder composition taken with a scanning electron microscope at 100 times magnification is shown in FIG.

[0087] Three-dimensional molding was similarly performed using this powder composition (C). Both the obtained X-direction bending test piece and Z-direction bending test piece were free of defects or irregularities and had excellent quality. The brightness of the obtained three-dimensional molded object was 62, and the yellowness was 15. The X-direction bending modulus was 6800 MPa, the bending strength was 115 MPa, and the Z-direction bending modulus was 5200 MPa, the bending strength was 68 MPa. The deflection temperature under load at 1.8 MPa was 241°C. X-ray CT observation of this X-direction bending test piece revealed a porosity of 3.6% by volume, a sphere-equivalent diameter of the pores of 34 μm, and a volume of 0.1 mm ３ The number of voids having the above size was 214. Table 1 shows the powder composition (C) used and the three-dimensional shaped article obtained.

[0088] Example 2 A powder composition (c1) was prepared in the same manner as in Comparative Example 1, except that the amount of polyarylene sulfide resin powder in Production Example 1 was changed to 12 kg and the amount of glass fiber EPG40M-01N was changed to 8 kg. This was then subjected to three-dimensional modeling in the same manner as in Comparative Example 1, and the powder remaining in tank 1 was recovered. This remaining powder was designated as powder composition (c2). 14 kg of powder composition (c2) and 6 kg of powder composition (c1) were blended to obtain powder composition (C). Three-dimensional modeling was similarly performed using this powder composition (C). No defects were observed in the obtained three-dimensionally shaped object, but slight irregularities were observed on the 10 mm wide x 80 mm long surface of the Z-direction bending test specimen. The powder composition (C) used and the obtained three-dimensionally shaped object are summarized in Table 1.

[0089] Example 3 Powder composition (c1) was prepared in the same manner as in Comparative Example 1, except that the amount of polyarylene sulfide resin powder in Production Example 1 was changed to 12 kg and the amount of glass fiber EPG70M-01N (manufactured by Nippon Electric Glass Co., Ltd., average major axis diameter 71 μm) was changed to 8 kg. This was subjected to three-dimensional printing in the same manner as in Comparative Example 1, and the powder remaining in tank 1 was recovered. This residual powder was designated powder composition (c2). 10 kg of powder composition (c2) and 10 kg of powder composition (c1) were blended to obtain powder composition (C). Three-dimensional printing was similarly performed using this powder composition (C). Some of the obtained three-dimensionally shaped objects had visible voids. Furthermore, slight irregularities were observed on the 10 mm wide × 80 mm long surface of the Z-direction bending test specimen. The powder composition (C) used and the obtained three-dimensionally shaped objects are summarized in Table 1.

[0090] [Example 4] Carbon fiber ("PX35" manufactured by Zoltek Corporation) was screened at room temperature under atmospheric pressure using a Turbo Screener (Turbo Corporation) with a 40 μm mesh size at a rotation speed of 600 rpm to remove long fibers. Carbon fiber was obtained with an average fiber length of 55 μm, a diameter of 7.2 μm, and a ratio of fibers 200 μm or larger of 0.24%. A powder composition (c1) was prepared in the same manner as in Comparative Example 1, except that the amount of polyarylene sulfide resin powder in Production Example 1 was changed to 14 kg and the amount of carbon fiber to 6 kg. The melting point of this powder composition (c1) measured using a differential scanning calorimeter was 296°C. The loss tangent of this powder composition (c1) at 324°C was 3.8, and the yellowish b ０ * was -1.8. Three-dimensional modeling was carried out using this in the same manner as in Comparative Example 1. The obtained X-direction bending test piece and Z-direction bending test piece were free of defects and irregularities and were of excellent quality. The brightness of the obtained three-dimensional model was 39 and the yellowness was 2.7. The powder composition (C) used and the obtained three-dimensional model are summarized in Table 1.

[0091] [Example 5] The powder remaining in tank 1 of the three-dimensional modeling apparatus in Example 4 was recovered, and 10 kg of this remaining powder was blended with 10 kg of powder composition (c1). The blend was mixed using a cross rotary mixer under conditions of nitrogen atmosphere, room temperature, and normal pressure while rotating and revolving, and three-dimensional modeling was similarly performed to a depth of 180 mm. This constitutes the first recycling modeling. This recycling modeling was repeated twice, and 10 kg of powder composition (c2), which had been subjected to a thermal load of approximately 15 hours of three-dimensional modeling three times while blending 50 wt% of powder composition (c1), was blended with 10 kg of powder composition (c1), and mixed in the same manner to obtain powder composition (C). The melting point of this powder composition (C) measured using a differential scanning calorimeter was 296°C. The loss tangent of powder composition (C) at 326°C was 3.1. The yellowish b of powder composition (c1) ０ * is -1.8, and the yellowness b* of powder composition (C) is 2.7, and b*-b ０ *=4.5.

[0092] Three-dimensional modeling was similarly performed using this powder composition (C). Both the obtained X-direction bending test pieces and Z-direction bending test pieces were free of defects or irregularities and had excellent quality. The brightness of the obtained three-dimensional model was 36, and the yellowness was 3.3. The powder composition (C) used and the obtained three-dimensional model are summarized in Table 1.

[0093] Comparative Example 2 A powder composition (c1) was prepared in the same manner as in Comparative Example 1, except that the amount of polyarylene sulfide resin powder in Production Example 1 was changed to 17 kg and the amount of glass fiber EPG40M-01N was changed to 3 kg. This was then subjected to three-dimensional modeling in the same manner as in Comparative Example 1, and the powder remaining in Tank 1 was recovered. This remaining powder was designated as powder composition (c2). 10 kg of powder composition (c2) and 10 kg of powder composition (c1) were blended to obtain powder composition (C). Three-dimensional modeling was similarly performed using this powder composition (C). The obtained three-dimensionally shaped object was free of defects or irregularities and had excellent quality; however, the flexural modulus was insufficient in both the X and Z directions, resulting in insufficient rigidity. Furthermore, the deflection temperature under load was 184°C, and the heat resistance was also insufficient. The powder composition (C) used and the obtained three-dimensionally shaped object are summarized in Table 1.

[0094] Comparative Example 3 A powder composition (c1) was prepared in the same manner as in Comparative Example 1, except that the amount of polyarylene sulfide resin powder in Production Example 1 was changed to 12 kg and the amount of glass fiber EPG70M-01N was changed to 8 kg. This was subjected to three-dimensional modeling in the same manner as in Comparative Example 1, and the powder remaining in Tank 1 was recovered. This remaining powder was designated as powder composition (c2). 20 kg of this powder composition (c2) was used, but without the addition of powder composition (c1), to designate powder composition (C). Three-dimensional modeling was similarly performed using this powder composition (C). During three-dimensional modeling, a phenomenon occurred in which the edges of the molten surface irradiated with the laser appeared to be floating, resulting in a three-dimensionally modeled object with warped edges. Numerous voids were also observed visually. Furthermore, clear irregularities were observed on the 10 mm wide x 80 mm long surface of the Z-direction bending test specimen. The powder composition (C) used and the resulting three-dimensionally modeled object are summarized in Table 1.

[0095]

[0096] The three-dimensionally shaped object of the present invention can be obtained by recycling the residual powder used in three-dimensional shaping to obtain a powder composition exhibiting good mechanical properties.Furthermore, even in the recycling process, a three-dimensionally shaped object having excellent rigidity and heat resistance can be obtained, and is particularly suitable for use in final products and spare parts in industries such as aerospace and automobiles.

[0097] REFERENCE SIGNS LIST 1 Tank for forming object 2 Tank stage for forming object 3 Supply tank pre-filled with powder composition to be supplied 4 Tank stage pre-filled with powder composition to be supplied 5 Recoater 6 Thermal energy 7 X, Y, Z coordinate system 8 Plane direction for laminating powder composition 9 Height direction for laminating powder composition 10 Three-dimensional object P Material powder

Claims

1. A powder composition (C) comprising a polyarylene sulfide resin powder (A) and an inorganic reinforcing material (B), wherein the number average particle size of the polyarylene sulfide resin powder (A) is 1 μm or more and 100 μm or less, the average major axis diameter of the inorganic reinforcing material (B) is 10 μm or more and 150 μm or less, the inorganic reinforcing material (B) is contained in an amount of 20 wt % or more and 60 wt % or less based on the total weight of the powder composition (C), and the loss tangent of the powder composition (C) at a temperature of the melting point of the polyarylene sulfide resin powder (A) contained in the powder composition (C) + 30°C is 3 or more and 25 or less.

2. The powder composition according to claim 1, wherein the powder composition (C) is a mixture of a powder composition (c1) to which no thermal load has been applied and a powder composition (c2) to which a thermal load has been applied, and the powder composition (c1) accounts for 10% by weight or more and 80% by weight or less of the total weight of the powder composition (C).

3. Yellowness b of the powder composition (c1) ０ * and the yellowness b* of the powder composition (C) is 1≦b*−b ０ The powder composition according to claim 2, wherein *≦20.

4. The powder composition according to claim 2, wherein the polyarylene sulfide resin powder (a1) contained in said powder composition (c1) has a melt flow rate of 70 g / 10 min or more and 200 g / 10 min or less.

5. The powder composition according to claim 1, wherein a test piece having a width of 10 mm, a length of 80 mm, and a thickness of 4 mm is prepared by powder bed fusion bonding, with the 80 mm length direction parallel to the direction of recoater movement (X direction), and the test piece has a flexural modulus in the X direction of 5000 MPa or more, as measured in accordance with JIS K7171 (2016), and a flexural modulus in the Z direction of 4000 MPa or more, as measured in accordance with JIS K7171 (2016), when the test piece is prepared with the 80 mm length direction parallel to the lamination direction (Z direction).

6. The powder composition according to any one of claims 1 to 5, which is a powder composition for producing a three-dimensional object by powder bed fusion.

7. A method for producing a three-dimensional object by powder bed fusion using the powder composition according to any one of claims 1 to 5.

8. A three-dimensional object produced by powder bed fusion using the powder composition according to any one of claims 1 to 5.

9. X-ray CT measurement revealed a 40mm ３ The volume observed within the field of view is 0.1 mm ３ The three-dimensional structure according to claim 8 , wherein the number of pores having a size equal to or larger than 400 is 400 or less.

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