PPS composite powder material for additive manufacturing and preparation method thereof

Abstract

The invention discloses a PPS composite powder material for additive manufacturing and a preparation method, and belongs to the technical field of high polymer materials and additive manufacturing, the method comprises the following steps: melting and mixing PPS granules, a functional additive, an antioxidant A, a nucleating agent and a composite diluent to form a homogeneous solution; after film casting, curing to realize solid-liquid phase separation; extracting to remove the diluent, cleaning and drying the obtained precipitate, and mixing with the flow promoter and the antioxidant B to obtain a finished product. The preparation method comprises the following steps: carrying out in-situ compounding by virtue of a TIPS technology, and regulating and controlling a phase separation process by virtue of a composite diluent and a nano nucleating agent, so as to prepare sphericity gt; 95% of powder with narrow particle size distribution; the functional additive and the PPS matrix form a covalent bonding core-shell structure in phase separation, so that the agglomeration problem is solved, and the mechanical strength and heat resistance of the material are remarkably improved; the process does not need post-treatment, and the multi-dimensional requirements of the fields of aerospace, automobile lightweight and the like on the high-performance PPS powder can be met by adjusting the types / proportions of the auxiliaries.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer materials and additive manufacturing, and specifically relates to a PPS composite powder material for additive manufacturing and a preparation method thereof. Background Art

[0002] As one of the core technologies driving the transformation of the manufacturing industry, additive manufacturing is reshaping modern industrial production methods. Selective laser sintering (SLS), with its mold-free and moldable capabilities for forming complex cavity structures, has become a core process in high-end manufacturing applications such as aerospace fuel nozzles, lightweight automotive components, and personalized medical implants. With the surging demand for high-temperature, corrosion-resistant, and high-precision structural parts, SLS technology is placing increasingly stringent demands on the comprehensive performance of powder materials. While current mainstream SLS materials, such as nylon 12, offer good formability, their heat deflection temperature is only approximately 55°C, failing to meet the demands of high-temperature applications such as engine compartments. While polyetheretherketone (PEEK) offers excellent temperature resistance, its raw material cost is over 10 times that of nylon, and it is prone to warping during the sintering process. Thermoplastic polyurethane (TPU), on the other hand, suffers from poor aging resistance and is prone to performance degradation under long-term dynamic loads.

[0003] Against this backdrop, polyphenylene sulfide (PPS), a semi-crystalline specialty engineering plastic, is considered a highly promising material for SLS due to its excellent high-temperature resistance (long-term operating temperature up to 200°C), outstanding mechanical strength, and exceptional chemical resistance. PPS boasts a high melting point of 280-290°C, a heat deformation temperature exceeding 260°C, and can operate stably for long periods at 220°C. Its flexural strength exceeds 140 MPa, and it exhibits near-zero moisture absorption and excellent resistance to acid and alkali corrosion, making it particularly suitable for the manufacture of precision components that operate in high- and low-temperature environments. However, converting this high-performance resin into a high-quality powder suitable for SLS processing still requires overcoming multiple technical barriers. PPS powders produced by traditional mechanical pulverization methods often exhibit irregular morphology and a wide particle size distribution, resulting in poor powder flowability. This makes PPS susceptible to defects such as uneven powder spreading and weak interlayer bonding during SLS processing. While spray drying can improve powder sphericity, high-temperature atomization can easily cause PPS molecular chains to break, reducing the impact strength of molded parts by over 30%. Furthermore, the SLS process often requires the addition of various functional additives (such as reinforcing fibers and conductive fillers) to the powder to meet specific application requirements. Application No. 201711457505.0 directly mixes PPS powder with functional additives (such as glass fiber and glass flakes) using a high-speed mixer. Application No. 202010950671.X first prepares a PPS semi-finished powder film by cryogenic pulverization, then thoroughly mixes the PPS semi-finished powder and functional additives in a blender. Existing preparation methods often combine PPS powder and functional additives through mechanical mixing, but this method struggles to achieve uniform dispersion of the additives within the PPS matrix, severely limiting the application of PPS in functional SLS products. Furthermore, the high melting point of PPS imposes special requirements on its powder preparation process, making conventional solvent precipitation methods difficult to implement due to the lack of suitable solvent systems. These technical bottlenecks have resulted in a lack of high-quality PPS powder materials suitable for the SLS process on the market. There is an urgent need to develop a new preparation method that can take into account powder morphology control, uniform dispersion of functional additives and process feasibility. Summary of the Invention

[0004] In order to overcome the above shortcomings, the present invention provides a PPS composite powder material for additive manufacturing and a preparation method thereof.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is: A method for preparing a PPS composite powder material for additive manufacturing comprises the following steps: (1) PPS pellets, functional additives, antioxidant A, and nucleating agent are mixed and then compound diluent is added for secondary mixing; (2) Add the mixture obtained in step (1) into a glass reactor, heat it to 180-220°C and hold it for 30 minutes, then heat it to 220-260°C and stir it for 0.5-4 hours to form a homogeneous solution; (3) Pour the homogeneous solution into a container at 210-260°C to cast a film, and then transfer it to a 20-150°C environment for curing for 0.5-3 hours to achieve solid-liquid phase separation; (4) After cooling to room temperature, an extractant is added to remove the diluent and separate the precipitate; (5) The precipitate is washed and dried to obtain primary powder, which is then mixed with a flow aid and antioxidant B to obtain finished powder.

[0006] Further optimized, the raw materials in step (1) include, by weight: 20-50 parts of PPS pellets, 0.01-0.1 parts of antioxidant A, 0-0.5 parts of nucleating agent, 50-80 parts of composite diluent, and 0.5-20 parts of functional additives.

[0007] Further optimized, the functional additive is selected from one or more of graphene, carbon nanotubes, carbon fiber, glass fiber, carbon black, boron nitride, silicon carbide, copper powder, and silver powder.

[0008] Further optimization, the composite diluent includes a main diluent and a secondary diluent, wherein the main diluent accounts for 50~95% of the total mass of the composite diluent and is selected from one of ethylene carbonate, diphenyl carbonate, diphenyl sulfone, caprolactam, acetyl tributyl citrate, dibenzoyl ketone, and cyclohexane 1,2-dicarboxylic acid diisononyl ester, and the secondary diluent is specifically one of glycerol, triacetin, polyethylene glycol monomethyl ether, polyethylene glycol dimethyl ether, dibutyl sebacate, dimethyl phthalate, and acetamide.

[0009] Further optimized, the nucleating agent is an inorganic nanoparticle with a particle size of 50 to 500 nm, selected from one of silicon dioxide, zinc oxide, copper oxide, titanium dioxide, hydroxyapatite, calcium carbonate, talc, and montmorillonite.

[0010] Further optimization, the antioxidant A is mainly a hindered phenol antioxidant, selected from tetrakis [β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] pentaerythritol ester, β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate octadecyl ester, bis (3,5-di-tert-butyl-4-hydroxyphenyl) propionyl) hydrazine, 2,2'-oxalamido-bis [ethyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl)] propionate, N,N'-hexamethylenebis (3,5-di-tert-butyl-4-hydroxyphenylpropionamide), 1,3,5-tris (3,5-di-tert-butyl-4-hydroxybenzyl) -1,3,5-triazine-2,4,6 One or two of (1H,3H,5H)-trione, triethylene glycol bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], 2,2'-thioethylene glycol bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 2,6-di-tert-butyl-4-methylphenol, 4,4'-bis(phenylisopropyl)diphenylamine, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, and 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,2H,5H)-trione.

[0011] Further optimization, the mixing ratio of the raw materials in step (5) is: 60-95 parts of primary powder, 5-40 parts of flow aid, and 0.01-0.2 parts of antioxidant B.

[0012] Further optimized, the antioxidant B is a phosphite or thioester antioxidant, selected from one of tris(2,4-di-tert-butylphenyl) phosphate, bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite, bis(2,4-dicumylphenyl) pentaerythritol-diphosphite, distearyl thiodipropionate, and pentaerythritol tetra(3-laurylthiopropionate).

[0013] Further optimized, the flow aid is one or two of fumed silica, fumed alumina, and nano-ceramic particles.

[0014] A PPS composite powder material for additive manufacturing has a spherical structure, a sphericity greater than 95%, a particle size distribution D90 / D10 less than 2.0, and a functional additive uniformly dispersed in a PPS matrix in a chemically bonded form.

[0015] Further optimization is performed, where the content of the functional additive is 5-40 wt% of the total weight of the powder, and the surface of the functional additive forms a covalent bond with the PPS matrix.

[0016] The beneficial effects of the present invention are: 1. This invention systematically solves the core problem in the preparation of existing PPS powder materials for additive manufacturing by combining the TIPS method with in-situ compounding technology of functional additives. Compared with the problems of irregular morphology, wide particle size distribution and poor fluidity caused by traditional mechanical pulverization methods, this invention produces PPS powder with high sphericity and narrow particle size distribution by precisely controlling the phase separation conditions, significantly improving powder fluidity and ensuring powder spreading uniformity and interlayer bonding strength during the SLS process. 2. The present invention uses in-situ composite technology to achieve uniform coating of functional additives (such as carbon fibers, carbon nanotubes, graphene, etc.) during the phase separation process, forming a composite powder with PPS as the shell and the functional additive as the core. This composite powder not only solves the problem of additive agglomeration caused by traditional mechanical mixing, but also significantly enhances the interfacial bonding between the additive and the matrix through interfacial chemical bonding, making the composite powder have high temperature resistance, high strength and specific functional properties; 3. The present invention has developed a synergistic control strategy for a composite diluent system and a nucleating agent. While simplifying the process flow, it achieves continuous control of powder particle size and morphology, and can obtain powder materials that meet SLS requirements without additional post-processing steps. By adjusting the types and proportions of functional additives, the precise design of material properties can be flexibly achieved to meet the multi-dimensional performance requirements of PPS powder materials in high-value-added fields such as aerospace, lightweight automobiles, and medical implants, laying a solid foundation for the large-scale application of high-performance PPS materials in the field of additive manufacturing. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is an SEM image of the PPS powder prepared in Example 1 of the present invention; Figure 2 is the particle size distribution curve of the PPS powder prepared in Example 1 of the present invention; Figure 3 This is an SEM image of the PPS bulk material prepared in Comparative Example 3 of the present invention. DETAILED DESCRIPTION

[0018] In order to more clearly understand the above-mentioned objects, features and advantages of the present invention, the present invention is described in detail below in conjunction with specific embodiments. The following embodiments are implemented based on the technical solutions of the present invention, and provide detailed implementation methods and specific operating procedures. However, the present invention can also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the following embodiments.

[0019] Example 1 A PPS composite powder material (thermal conductive composite powder) for additive manufacturing is prepared according to the following method: 1) PPS pellets with a molecular weight of 20,000 and a melt index of 200 g / 10 min, boron nitride flakes of 10 μm in diameter, 2,6-di-tert-butyl-4-methylphenol, and 200 nm silica were kneaded in a mixer at 1,000 rpm for 20 min to ensure thorough mixing. A composite diluent consisting of caprolactam and dibutyl sebacate (2:1) was then added and mixed thoroughly. The components and their weight ratios are as follows: 30 parts of PPS granules 5 parts of boron nitride 0.1 part of 2,6-di-tert-butyl-4-methylphenol 0.4 parts of silicon dioxide 64.5 parts of composite diluent 2) The mixture obtained in step 1) was added to a glass reactor and heated to 200°C at a rate of 20°C / min for 30 min, then heated to 250°C at a rate of 5°C / min with stirring for 2 h at 400 rpm to completely dissolve the PPS pellets and obtain a homogeneous solution. 3) The homogeneous solution obtained in step 2) was poured into a flat-bottomed metal tray at 240°C and cast into a film, which was then transferred to a forced air oven at 120°C for curing for 2 h to allow solid-liquid phase separation between the PPS and the diluent in the homogeneous solution; 4) The solidified material obtained in step 3) was transferred to a natural environment and continued to cool to room temperature. Subsequently, an extractant consisting of deionized water and ethanol (1:2) was poured into the container and extracted at 30°C for 5 hours to completely remove the composite diluent. That is, the precipitate in the container was PPS powder; 5) First, the PPS powder obtained in step 4) was separated by vacuum filtration, and then the PPS powder was washed five times with ethanol at 40°C, each washing time being 20 minutes. After each washing, the PPS powder was separated by vacuum filtration. After washing, the PPS powder was vacuum dried at 60°C for 3 hours to remove residual solvent, thereby obtaining a PPS primary powder. Finally, 80 parts of the PPS primary powder, 19.9 parts of fumed silica, and 0.1 parts of distearyl thiodipropionate were uniformly mixed in a mixer to obtain a PPS composite powder material for additive manufacturing with thermal conductivity.

[0020] The test shows that the PPS primary powder has a regular spherical structure, such as Figure 1As shown in the figure, there is no distribution of functional additives (flake-like boron nitride) in the SEM image, nor is there any distribution of functional additives on the surface of the PPS powder. This indicates that the functional additives are encapsulated in the PPS, and the particle size distribution range of the powder is narrow, mainly distributed in the range of 30~60 μm, as shown in the figure. Figure 2 The angle of repose of the PPS composite powder is 23.6° and the bulk density is 0.42 g / cm 3 .

[0021] Example 2 A PPS composite powder material (conductively reinforced composite powder) for additive manufacturing is prepared according to the following method: 1) PPS pellets with a molecular weight of 50,000 and a melt index of 50 g / 10 min, silver powder with a particle size of 20 μm, carbon fiber with a length of 10 μm, β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, and 500 nm montmorillonite were mixed in a mixer at a speed of 500 rpm for 50 min to fully mix them. Subsequently, a composite diluent consisting of diphenyl sulfone and polyethylene glycol monomethyl ether (5:1) was added and the mixture was fully mixed. The weight ratio of the components was as follows: 40 parts of PPS granules 5 parts silver powder 5 parts carbon fiber 0.1 part of β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate 0.5 parts of montmorillonite 49.4 parts of composite diluent 2) The mixture obtained in step 1) was added to a glass reactor and heated to 220°C at a rate of 10°C / min for 30 min. The temperature was then raised to 260°C at a rate of 2°C / min with stirring for 4 h at a stirring rate of 500 rpm to completely dissolve the PPS pellets and obtain a homogeneous solution. 3) The homogeneous solution obtained in step 2) was poured into a flat-bottomed quartz Petri dish at 255°C to form a film, which was then transferred to a forced air oven at 100°C for curing for 3 h to allow solid-liquid phase separation between the PPS and the diluent in the homogeneous solution. 4) The solidified material obtained in step 3) was transferred to a natural environment and continued to cool to room temperature. Subsequently, an extractant composed of methanol and isopropanol (1:1) was poured into the container and extracted at 20°C for 3 hours to completely remove the composite diluent, i.e., the precipitate in the container was PPS powder; 5) First, the PPS powder obtained in step 4) was separated by centrifugation, and then the PPS powder was washed three times with methanol at 30°C, each washing time being 30 minutes. After each washing, the PPS powder was separated by centrifugation. After washing, the PPS powder was vacuum dried at 80°C for 4 hours to remove residual solvent, thereby obtaining PPS primary powder. Finally, 95 parts of PPS primary powder, 4.8 parts of nano-ceramic particles, and 0.2 parts of tris(2,4-di-tert-butylphenyl) phosphite were uniformly mixed in a mixer to obtain a PPS composite powder material for additive manufacturing with enhanced conductivity.

[0022] The test results show that the primary PPS powder has a regular spherical structure, the functional additives are encapsulated in the PPS, and the particle size distribution of the powder is narrow, mainly distributed in the range of 40-80 μm. The angle of repose of the PPS composite powder is 23.6°, and the bulk density is 0.42 g / cm 3 .

[0023] Example 3 A PPS composite powder material (conductive composite powder) for additive manufacturing is prepared according to the following method: 1) PPS pellets with a molecular weight of 10,000 and a melt index of 300 g / 10 min, carbon black with a particle size of 5 μm, copper powder with a particle size of 10 μm, 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,2H,5H)-trione, and 100 nm titanium dioxide were mixed in a mixer at a speed of 1000 rpm for 20 min to ensure thorough mixing. Subsequently, a composite diluent consisting of caprolactam and dibutyl sebacate (3:1) was added and the mixture was thoroughly mixed. The components and their weight ratios are as follows: 20 parts of PPS granules 5 parts carbon black 10 parts copper powder 0.05 parts of 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,2H,5H)-trione 0.05 parts of titanium dioxide 64.9 parts of composite diluent 2) The mixture obtained in step 1) was added to a glass reactor and heated to 180°C at a rate of 15°C / min for 30 min. The temperature was then raised to 220°C at a rate of 10°C / min with stirring for 4 h at a stirring rate of 600 rpm to completely dissolve the PPS pellets and obtain a homogeneous solution. 3) The homogeneous solution obtained in step 2) was poured into a flat-bottomed metal tray at 210°C and cast into a film, which was then transferred to an air environment at 30°C for curing for 0.5 h to allow solid-liquid phase separation between the PPS and the diluent in the homogeneous solution; 4) The solidified material obtained in step 3) was transferred to a natural environment and continued to cool to room temperature. Ethanol was then poured into the container as an extractant and extracted at 10°C for 6 hours to completely remove the composite diluent, i.e., the precipitate in the container was PPS powder; 5) First, the PPS powder obtained in step 4) was separated by vacuum filtration, and then the PPS powder was washed five times with ethanol at 20°C, each washing time being 10 minutes. After each washing, the PPS powder was separated by vacuum filtration. After washing, the PPS powder was vacuum dried at 50°C for 4 hours to remove residual solvent, thereby obtaining a PPS primary powder. Finally, 60 parts of the PPS primary powder, 39.95 parts of fumed alumina, and 0.05 parts of pentaerythritol tetrakis(3-laurylthiopropionate) were uniformly mixed in a mixer to obtain a PPS composite powder material for additive manufacturing with conductive properties.

[0024] The test results show that the primary PPS powder has a regular spherical structure, the functional additives are encapsulated in the PPS, and the particle size distribution range of the powder is narrow, mainly distributed in the range of 40-90 μm. The angle of repose of the PPS composite powder is 22.8° and the bulk density is 0.82 g / cm 3 .

[0025] Example 4 A PPS composite powder material (conductive and thermally conductive composite powder) for additive manufacturing is prepared according to the following method: 1) PPS pellets with a molecular weight of 30,000 and a melt index of 100 g / 10 min, copper powder with a particle size of 10 μm, silicon carbide with a flake size of 5 μm, triethylene glycol bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate], 4,4'-di(phenylisopropyl)diphenylamine, and 200 nm zinc oxide were mixed in a mixer at 500 rpm for 60 min to ensure thorough mixing. A composite diluent consisting of benzophenone and acetamide (4:1) was then added and mixed thoroughly. The components and their weight ratios are as follows: 30 parts of PPS granules 5 parts copper powder 5 parts of silicon carbide 0.03 parts of triethylene glycol bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate] 0.02 parts of 4,4'-di(phenylisopropyl)diphenylamine 0.05 parts of zinc oxide 59.9 parts of composite diluent 2) The mixture obtained in step 1) was added to a glass reactor and heated to 210°C at a rate of 20°C / min for 30 min. The temperature was then raised to 250°C at a rate of 5°C / min with stirring for 3 h at 200 rpm to completely dissolve the PPS pellets and obtain a homogeneous solution. 3) The homogeneous solution obtained in step 2) was poured into a flat-bottomed metal tray at 245°C and cast into a film, which was then transferred to a forced air oven at 120°C for curing for 1 hour to allow solid-liquid phase separation between the PPS and the diluent in the homogeneous solution; 4) The solidified material obtained in step 3) was transferred to a natural environment and continued to cool to room temperature. Isopropyl alcohol was then poured into the container as an extractant and extracted at 30°C for 4 hours to completely remove the composite diluent, i.e., the precipitate in the container was PPS powder; 5) First, the PPS powder obtained in step 4) was separated by vacuum filtration, and then the PPS powder was washed four times with isopropyl alcohol at 40°C, each washing time being 20 minutes. After each washing, the PPS powder was separated by vacuum filtration. After washing, the PPS powder was vacuum dried at 80°C for 3 hours to remove residual solvent, thereby obtaining PPS primary powder. Finally, 65 parts of PPS primary powder, 34.9 parts of fumed aluminum oxide, and 0.1 part of tris(2,4-di-tert-butylphenyl) phosphite were uniformly mixed in a mixer to obtain a PPS composite powder material for additive manufacturing with electrical and thermal conductivity.

[0026] The test results show that the primary PPS powder has a regular spherical structure, the functional additives are encapsulated in the PPS, and the particle size distribution of the powder is narrow, mainly distributed in the range of 40-80 μm. The angle of repose of the PPS composite powder is 26.4° and the bulk density is 0.72 g / cm 3 .

[0027] Example 5 A PPS composite powder material (thermal conductive composite powder) for additive manufacturing is prepared according to the following method: 1) PPS pellets with a molecular weight of 20,000 and a melt index of 150 g / 10 min, boron nitride flakes of 20 μm in diameter, bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hydrazine, and 200 nm silica were kneaded in a mixer at 1000 rpm for 20 min to ensure thorough mixing. A composite diluent consisting of caprolactam and dibutyl sebacate (5:1) was then added and mixed thoroughly. The components and their weight ratios are as follows: 35 parts of PPS pellets 10 parts of boron nitride 0.1 part of bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hydrazine 0.1 parts of silicon dioxide 54.8 parts of composite diluent 2) The mixture obtained in step 1) was added to a glass reactor and heated to 220°C at a rate of 10°C / min for 30 min. The temperature was then raised to 240°C at a rate of 10°C / min with stirring for 0.5 h at a stirring rate of 600 rpm to completely dissolve the PPS pellets and obtain a homogeneous solution. 3) The homogeneous solution obtained in step 2) was poured into a flat-bottomed quartz Petri dish at 240°C to form a film, which was then transferred to an 80°C forced air oven for curing for 1 hour to allow solid-liquid phase separation between the PPS and the diluent in the homogeneous solution. 4) The solidified material obtained in step 3) was transferred to a natural environment and continued to cool to room temperature. Subsequently, an extractant consisting of deionized water and methanol (1:3) was poured into the container and extracted at 40°C for 4 hours to completely remove the composite diluent. That is, the precipitate in the container was PPS powder; 5) First, the PPS powder obtained in step 4) was separated by vacuum filtration, and then the PPS powder was washed five times with methanol at 40°C, each washing time being 10 minutes. After each washing, the PPS powder was separated by vacuum filtration. After washing, the PPS powder was vacuum dried at 70°C for 3 hours to remove residual solvent, thereby obtaining PPS primary powder. Finally, 70 parts of PPS primary powder, 29.95 parts of nano-ceramic particles, and 0.05 parts of bis(2,4-dicumylphenyl)pentaerythritol-diphosphite were uniformly mixed in a mixer to obtain a PPS composite powder material for additive manufacturing with thermal conductivity.

[0028] The test results show that the primary PPS powder has a regular spherical structure, the functional additives are encapsulated in the PPS, and the particle size distribution of the powder is narrow, mainly distributed in the range of 30-80 μm. The angle of repose of the PPS composite powder is 24.2°, and the bulk density is 0.52 g / cm 3 .

[0029] Example 6 A PPS composite powder material (reinforced composite powder) for additive manufacturing is prepared according to the following method: 1) PPS pellets with a molecular weight of 40,000 and a melt index of 100 g / 10 min, 20 μm glass fiber, 2,2'-thioethylene glycol bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and 300 nm talc were kneaded in a mixer at 1100 rpm for 30 min to ensure thorough mixing. A composite diluent consisting of diisononyl cyclohexane-1,2-dicarboxylate and dimethyl phthalate (2:1) was then added and mixed thoroughly. The components and their weight ratios are as follows: 25 parts of PPS granules 3 parts glass fiber 0.05 parts of 2,2'-thioethylene glycol bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] 0.1 parts of talcum powder 71.85 parts of composite diluent 2) The mixture obtained in step 1) was added to a glass reactor and heated to 210°C at a rate of 20°C / min for 30 min. The temperature was then raised to 260°C at a rate of 2°C / min with stirring for 1 h at a stirring rate of 100 rpm to completely dissolve the PPS pellets and obtain a homogeneous solution. 3) The homogeneous solution obtained in step 2) was poured into a flat-bottomed quartz Petri dish at 250°C to form a film, which was then transferred to a forced air oven at 60°C for curing for 2 h to allow solid-liquid phase separation between the PPS and the diluent in the homogeneous solution. 4) The solidified material obtained in step 3) was transferred to a natural environment and continued to cool to room temperature. Subsequently, an extractant consisting of methanol and ethanol (1:1) was poured into the container and extracted at 30°C for 6 hours to completely remove the composite diluent, i.e., the precipitate in the container was PPS powder; 5) First, the PPS powder obtained in step 4) was separated by vacuum filtration, and then the PPS powder was washed four times with ethanol at 30°C, each washing time being 20 minutes. After each washing, the PPS powder was separated by vacuum filtration. After washing, the PPS powder was vacuum dried at 50°C for 5 hours to remove residual solvent, thereby obtaining PPS primary powder. Finally, 90 parts of PPS primary powder, 9.8 parts of fumed titanium dioxide, and 0.2 parts of bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite were uniformly mixed in a mixer to obtain a PPS composite powder material for additive manufacturing with a reinforced effect.

[0030] The test results show that the primary PPS powder has a regular spherical structure, the functional additives are encapsulated in the PPS, and the particle size distribution of the powder is narrow, mainly distributed in the range of 40-90 μm. The angle of repose of the PPS composite powder is 25.2° and the bulk density is 0.57 g / cm 3 .

[0031] Example 7 A PPS composite powder material (thermal conductivity enhanced composite powder) for additive manufacturing is prepared according to the following method: 1) PPS pellets with a molecular weight of 30,000 and a melt index of 100 g / 10 min, carbon fibers of 20 μm in length, boron nitride flakes of 10 μm in diameter, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, and 200 nm hydroxyapatite were mixed in a mixer at 1000 rpm for 30 min to ensure thorough mixing. A composite diluent consisting of benzophenone and polyethylene glycol dimethyl ether (5:1) was then added and mixed thoroughly. The components and their weight ratios are as follows: 25 parts of PPS granules 5 parts carbon fiber 5 parts of boron nitride 0.1 part of 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene 0.1 part hydroxyapatite 64.8 parts of composite diluent 2) The mixture obtained in step 1) was added to a glass reactor and heated to 220°C at a rate of 20°C / min for 30 min. The temperature was then raised to 250°C at a rate of 10°C / min with stirring for 2 h at a stirring rate of 500 rpm to completely dissolve the PPS pellets and obtain a homogeneous solution. 3) The homogeneous solution obtained in step 2) was poured into a flat-bottomed quartz Petri dish at 245°C to form a film, which was then transferred to a forced air oven at 100°C for curing for 3 h to allow solid-liquid phase separation between the PPS and the diluent in the homogeneous solution. 4) The solidified material obtained in step 3) was transferred to a natural environment and continued to cool to room temperature. Subsequently, an extractant consisting of deionized water and ethanol (1:2) was poured into the container and extracted at 30°C for 5 hours to completely remove the composite diluent. That is, the precipitate in the container was PPS powder; 5) First, the PPS powder obtained in step 4) was separated by vacuum filtration, and then the PPS powder was washed with ethanol at 30°C for 5 times, each washing time being 10 minutes. After each washing, the PPS powder was separated by vacuum filtration. After washing, the PPS powder was vacuum dried at 40°C for 4 hours to remove residual solvent, thereby obtaining PPS primary powder. Finally, 85 parts of PPS primary powder, 14.9 parts of fumed alumina, and 0.1 part of distearyl thiodipropionate were uniformly mixed in a mixer to obtain a PPS composite powder material for additive manufacturing with enhanced thermal conductivity.

[0032] The test results show that the primary PPS powder has a regular spherical structure, the functional additives are encapsulated in the PPS, and the particle size distribution range of the powder is narrow, mainly distributed in the range of 30-80 μm. The angle of repose of the PPS composite powder is 26.7° and the bulk density is 0.49 g / cm 3 .

[0033] Comparative Example 1 Comparative Example 1 is exactly the same as steps 2) to 5) of Example 1. The only difference from step 1) of Example 1 is the use of a single diluent and a different configuration of a compound diluent. Specifically: 1) PPS pellets with a molecular weight of 20,000 and a melt index of 200 g / 10 min, 2,6-di-tert-butyl-4-methylphenol, and 200 nm silica were mixed in a mixer at 1,000 rpm for 20 min to ensure thorough mixing. A composite diluent consisting of caprolactam and dibutyl sebacate (1:2) was then added and mixed thoroughly. The components and their weight ratios are as follows: 30 parts of PPS granules 0.1 part of 2,6-di-tert-butyl-4-methylphenol 0.4 parts of silicon dioxide 69.5 parts of composite diluent 2) The mixture obtained in step 1) was added to a glass reactor and heated to 200°C at a rate of 20°C / min for 30 min, then heated to 250°C at a rate of 5°C / min with stirring for 2 h at 400 rpm to completely dissolve the PPS pellets and obtain a homogeneous solution. 3) The homogeneous solution obtained in step 2) was poured into a flat-bottomed metal tray at 240°C and cast into a film, which was then transferred to a forced air oven at 120°C for curing for 2 h to allow solid-liquid phase separation between the PPS and the diluent in the homogeneous solution; 4) The solidified material obtained in step 3) was transferred to a natural environment and continued to cool to room temperature. Subsequently, an extractant consisting of deionized water and ethanol (1:2) was poured into the container and extracted at 30°C for 5 hours to completely remove the composite diluent. That is, the precipitate in the container was PPS powder; 5) First, the PPS powder obtained in step 4) was separated by vacuum filtration, and then the PPS powder was washed with ethanol at 40°C for 5 times, each washing time being 20 minutes. After each washing, the PPS powder was separated by vacuum filtration. After washing, the PPS powder was vacuum dried at 60°C for 3 hours to remove residual solvent to obtain PPS primary powder. Finally, 80 parts of PPS primary powder, 19.9 parts of fumed silica, and 0.1 part of distearyl thiodipropionate were mixed uniformly in a mixer to obtain PPS powder material for additive manufacturing.

[0034] The test shows that the PPS primary powder has a regular spherical structure, such as Figure 1 As shown in the figure, the particle size distribution of the powder is narrow, mainly distributed in the range of 40~70 μm. The angle of repose of the PPS composite powder is 26.7°, and the bulk density is 0.41 g / cm 3 , but its powder material does not have the function of thermal conductivity.

[0035] Comparative Example 2 Comparative Example 2 is exactly the same as steps 1) to 4) of Example 1. The only difference from step 4) of Example 1 is that the flow aid and antioxidant B are not mixed into the PPS primary powder. Specifically: 1) PPS pellets with a molecular weight of 20,000 and a melt index of 200 g / 10 min, boron nitride flakes of 10 μm in diameter, 2,6-di-tert-butyl-4-methylphenol, and 200 nm silica were kneaded in a mixer at 1,000 rpm for 20 min to ensure thorough mixing. A composite diluent consisting of caprolactam and dibutyl sebacate (2:1) was then added and mixed thoroughly. The components and their weight ratios are as follows: 30 parts of PPS granules 5 parts of boron nitride 0.1 part of 2,6-di-tert-butyl-4-methylphenol 0.4 parts of silicon dioxide 64.5 parts of composite diluent 2) The mixture obtained in step 1) was added to a glass reactor and heated to 200°C at a rate of 20°C / min for 30 min, then heated to 250°C at a rate of 5°C / min with stirring for 2 h at 400 rpm to completely dissolve the PPS pellets and obtain a homogeneous solution. 3) The homogeneous solution obtained in step 2) was poured into a flat-bottomed metal tray at 240°C and cast into a film, which was then transferred to a forced air oven at 120°C for curing for 2 h to allow solid-liquid phase separation between the PPS and the diluent in the homogeneous solution; 4) The solidified material obtained in step 3) was transferred to a natural environment and continued to cool to room temperature. Subsequently, an extractant consisting of deionized water and ethanol (1:2) was poured into the container and extracted at 30°C for 5 hours to completely remove the composite diluent. That is, the precipitate in the container was PPS powder; 5) First, the PPS powder obtained in step 4) was separated by vacuum filtration, and then the PPS powder was washed with ethanol at 40°C for 5 times, each washing time was 20 minutes. After each washing, the PPS powder was separated by vacuum filtration. After the washing, the PPS powder was vacuum dried at 60°C for 3 hours to remove the residual solvent, thereby obtaining a PPS primary powder, which is a PPS composite powder material for additive manufacturing with thermal conductivity.

[0036] The test results show that the primary PPS powder has a regular spherical structure, and the particle size distribution range of the powder is narrow, mainly distributed in the range of 30~60 μm, the angle of repose is 27.8°, and the bulk density is 0.35 g / cm 3 However, the performance of the sintered specimens of the PPS primary powder without the addition of flow aid and antioxidant B is relatively poor (as shown in Table 1), and is not suitable for additive manufacturing.

[0037] Comparative Example 3 Comparative Example 3 is exactly the same as steps 2) to 5) of Example 1. The only difference from step 4) of Example 1 is that the flow aid and antioxidant B are not mixed into the PPS primary powder. Specifically: 1) PPS pellets with a molecular weight of 20,000 and a melt index of 200 g / 10 min, boron nitride flakes of 10 μm in diameter, 2,6-di-tert-butyl-4-methylphenol, and 200 nm silica were kneaded in a mixer at 1,000 rpm for 20 min to ensure thorough mixing. A composite diluent consisting of caprolactam and dibutyl sebacate (2:1) was then added and mixed thoroughly. The components and their weight ratios are as follows: 30 parts of PPS granules 5 parts of boron nitride 0.1 part of 2,6-di-tert-butyl-4-methylphenol 0.4 parts of silicon dioxide 64.5 parts of composite diluent 2) The mixture obtained in step 1) was added to a glass reactor and heated to 200°C at a rate of 20°C / min for 30 min, then heated to 250°C at a rate of 5°C / min with stirring for 2 h at 400 rpm to completely dissolve the PPS pellets and obtain a homogeneous solution. 3) The homogeneous solution obtained in step 2) was poured into a flat-bottomed metal tray at 240°C and cast into a film. The film was then transferred to a forced air oven at 120°C for curing for 2 h. Liquid-liquid phase separation occurred between the PPS and the diluent in the homogeneous solution. 4) The solidified material obtained in step 3) was transferred to a natural environment and continued to cool to room temperature. Subsequently, an extractant consisting of deionized water and ethanol (1:2) was poured into a container and extracted at 30°C for 5 hours to completely remove the composite diluent. In other words, the PPS in the container was in the form of lumps, and no PPS composite powder was prepared. 5) First, the PPS bulk material obtained in step 4) was separated by vacuum filtration, and then the PPS powder was washed with ethanol at 40°C for 5 times, each washing time was 20 minutes. After each washing, the PPS bulk material was separated by vacuum filtration. After the washing, the PPS powder was vacuum dried at 60°C for 3 hours to remove the residual solvent to obtain the PPS bulk material.

[0038] After testing, the PPS bulk material showed a network structure (such as Figure 3 (As shown in Figure 3), this network structure is typical of liquid-liquid phase separation. This indicates that an inappropriate diluent type or ratio causes PPS to undergo liquid-liquid phase separation, making it impossible to prepare PPS composite powder materials suitable for additive manufacturing.

[0039] Table 1 shows the performance parameters of the sintered specimens of PPS composite powders prepared in Examples 1-7 and Comparative Examples 1-2. The above shows and describes the main features, methods of use, basic principles, and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and improvements may be made to the present invention based on actual circumstances without departing from the spirit and scope of the present invention. Such changes and improvements are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a PPS composite powder material for additive manufacturing, characterized in that: The following steps are involved: (1) PPS pellets, functional additives, antioxidant A, and nucleating agent are mixed and then compound diluent is added for secondary mixing; (2) Add the mixture obtained in step (1) into a glass reactor, heat it to 180-220°C and hold it for 30 minutes, then heat it to 220-260°C and stir it for 0.5-4 hours to form a homogeneous solution; (3) Pour the homogeneous solution into a container at 210-260°C to cast a film, and then transfer it to a 20-150°C environment for curing for 0.5-3 hours to achieve solid-liquid phase separation; (4) After cooling to room temperature, an extractant is added to remove the diluent and separate the precipitate; (5) The precipitate is washed and dried to obtain primary powder, which is then mixed with a flow aid and antioxidant B to obtain finished powder.

2. The method for preparing a PPS composite powder material for additive manufacturing according to claim 1, wherein: The raw materials in step (1) include, by weight: 20-50 parts of PPS pellets, 0.01-0.1 parts of antioxidant A, 0-0.5 parts of nucleating agent, 50-80 parts of composite diluent, and 0.5-20 parts of functional additives.

3. The method for preparing a PPS composite powder material for additive manufacturing according to claim 1, wherein: The functional additive is selected from one or more of graphene, carbon nanotubes, carbon fiber, glass fiber, carbon black, boron nitride, silicon carbide, copper powder, and silver powder.

4. The method for preparing a PPS composite powder material for additive manufacturing according to claim 1, wherein: The composite diluent includes a main diluent and a secondary diluent, wherein the main diluent accounts for 50-95% of the total mass of the composite diluent and is selected from one of ethylene carbonate, diphenyl carbonate, diphenyl sulfone, caprolactam, acetyl tributyl citrate, dibenzoyl ketone, and cyclohexane 1,2-dicarboxylic acid diisononyl ester, and the secondary diluent is specifically one of glycerol, triacetin, polyethylene glycol monomethyl ether, polyethylene glycol dimethyl ether, dibutyl sebacate, dimethyl phthalate, and acetamide.

5. The method for preparing a PPS composite powder material for additive manufacturing according to claim 1, wherein: The nucleating agent is an inorganic nanoparticle with a particle size of 50 to 500 nm, selected from silicon dioxide, zinc oxide, copper oxide, titanium dioxide, hydroxyapatite, calcium carbonate, talc, and montmorillonite.

6. The method for preparing a PPS composite powder material for additive manufacturing according to claim 1, wherein: The antioxidant A is mainly a hindered phenol antioxidant, selected from pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecylβ-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hydrazine, 2,2'-oxalylamino-bis[ethyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)]propionate, N,N'-hexamethylenebis(3,5-di-tert-butyl- 4-hydroxyphenylpropionamide), 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, triethylene glycol bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], 2,2'-thioethylene glycol bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate], One or two of 2,6-di-tert-butyl-4-methylphenol, 4,4'-di(phenylisopropyl)diphenylamine, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, and 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,2H,5H)-trione.

7. The method for preparing a PPS composite powder material for additive manufacturing according to claim 1, wherein: The mixing ratio of the raw materials in step (5) is: 60-95 parts of primary powder, 5-40 parts of flow aid, and 0.01-0.2 parts of antioxidant B.

8. The method for preparing a PPS composite powder material for additive manufacturing according to claim 1, wherein: The antioxidant B is a phosphite or thioester antioxidant, selected from one of tris(2,4-di-tert-butylphenyl) phosphate, bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite, bis(2,4-dicumylphenyl) pentaerythritol-diphosphite, distearyl thiodipropionate, and pentaerythritol tetra(3-laurylthiopropionate).

9. The method for preparing a PPS composite powder material for additive manufacturing according to claim 1, wherein: The flow aid is one or two of fumed silicon dioxide, fumed aluminum oxide, and nano-ceramic particles.

10. The PPS composite powder material prepared by the method according to any one of claims 1 to 9, characterized in that: The PPS composite powder material has a spherical structure, a sphericity greater than 95%, a particle size distribution D90 / D10 less than 2.0, and a functional additive uniformly dispersed in the PPS matrix in a chemically bonded form. The content of the functional additive is 5-40wt% of the total weight of the powder.

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