Fluorine-containing resin for 3D printing and method for preparing the same

Abstract

The application discloses a fluorine-containing resin for 3D printing and a preparation method thereof, and belongs to the technical field of fluorine-containing resins. Rutile titanium dioxide and quartz powder are mixed according to superfine phase, medium-fine phase and coarse-grained phase powder, then calcium copper titanate is stirred and heated, a composite coupling agent is added, and the composite inorganic filler is obtained through stirring; the modified micro powder is dry-mixed with the composite inorganic filler to obtain dry-mixed material; propylene glycol methyl ether is added for dispersion, sand grinding is performed to obtain a base slurry; vacuum homogenization defoaming is performed, and closed curing is performed to obtain the fluorine-containing resin for 3D printing. Through the grading and compounding process of the rutile titanium dioxide and the quartz powder, the composite inorganic filler is prepared by combining the calcium copper titanate and the composite coupling agent, the crystallization behavior of polyvinylidene fluoride is effectively controlled, the volume shrinkage rate of the prepared fluorine-containing resin for 3D printing is controlled to be less than 2.12% after molding, the warpage is as low as less than 1.51%, and the size precision and the molding stability of the 3D printing product are significantly improved.

Description

Technical Field

[0001] This invention relates to the field of fluorinated resin technology, and more specifically to a fluorinated resin for 3D printing and its preparation method. Background Technology

[0002] 3D printing technology, with its advantages of digital molding, mold-free operation, and rapid fabrication of complex structures, has rapidly expanded into high-end manufacturing, precision components, and chemical corrosion protection. Fluoropolymers, with their excellent chemical corrosion resistance, high temperature resistance, low friction, insulation, and weather resistance, have become key materials for 3D printed components under harsh working conditions.

[0003] Polyvinylidene fluoride (PVDF), a semi-crystalline fluorinated thermoplastic resin with well-balanced comprehensive properties, is currently the most widely used fluorinated material in 3D printing. It possesses excellent thermal processability, making it compatible with conventional 3D printing processes such as fused deposition modeling (FDM / FFF) without requiring extreme sintering conditions. It also exhibits excellent resistance to acids and alkalis, organic solvents, and weathering, with a continuous operating temperature up to 150°C. Furthermore, it possesses good creep resistance and flame retardancy, and combines piezoelectric and dielectric properties, meeting the molding requirements of corrosion-resistant, heat-resistant, and functional structural components in fields such as chemical engineering, electronics, and new energy.

[0004] However, as a semi-crystalline polymer, PVDF has a high degree of crystallinity and a large volume shrinkage rate during the melting and cooling process of 3D printing, which can easily cause product warping, deformation, decreased dimensional accuracy and substrate peeling, especially for thick-walled parts and complex structures. At the same time, its low surface energy characteristics result in weak interlayer bonding force and interlayer strength that is far lower than the mechanical properties of the substrate, making it difficult to meet the requirements of load-bearing and high reliability conditions.

[0005] Based on this, the present invention designs a fluorinated resin for 3D printing and a method for preparing the same to solve the above problems. Summary of the Invention

[0006] To address the aforementioned shortcomings of existing technologies, this invention provides a method for preparing fluorinated resins for 3D printing, comprising the following steps: S1: Rutile titanium dioxide and quartz powder were dried at 80-95℃ for 2-3.5h and then subjected to airflow classification to obtain ultrafine phase D. 50 =0.15-0.5μm, medium-fine phase D 50 =1.0-1.8μm, coarse-grained phase D 50 Powder with a particle size of 2.2-3.0 μm was mixed with ultrafine, medium-fine and coarse-grained powders at a mass ratio of 3-4:2-3:1-2 to obtain pretreated rutile titanium dioxide powder and pretreated quartz powder. S2: By weight, add 4-7 parts of calcium copper titanate, 12-18 parts of pretreated rutile titanium dioxide powder and 6-10 parts of pretreated quartz powder to a mixer, stir and heat, and spray in 0.08-0.25 parts of composite coupling agent diluted with anhydrous ethanol, and stir to obtain the composite inorganic filler. S3: By weight, 18-24 parts of modified micro powder and compound inorganic filler are dry-mixed to obtain dry mixture; S4: Add 28-36 parts of propylene glycol methyl ether to the dry mixture for dispersion, and then sand mill to obtain the basic slurry; S5: Vacuum homogenize and degas the base slurry, and then cure it in a sealed environment to obtain a fluorinated resin for 3D printing; The modified micro powder is prepared by: Weigh out 72-85 parts by weight of polyvinylidene fluoride, 10-14 parts by weight of carboxylated nitrile rubber, 0.8-1.3 parts by weight of silane coupling agent, and 0.1-0.3 parts by weight of antioxidant. Polyvinylidene fluoride, carboxylated nitrile rubber and antioxidant are stirred, and then 0.2-0.4 parts of silane coupling agent are added and stirred to obtain a mixture; the mixture is melt-blended and extruded at 165-175℃, cooled, crushed and sieved to obtain a coarse blended powder; the coarse blended powder is stirred, and the remaining silane coupling agent is added during the stirring process; it is dried and sieved to obtain modified micro powder.

[0007] Furthermore, S2 specifically involves adding 4-7 parts by weight of calcium copper titanate, 12-18 parts by weight of pretreated rutile titanium dioxide powder, and 6-10 parts by weight of pretreated quartz powder to a mixer, stirring at 400-600 r / min and heating to 65-80℃, then spraying in 0.08-0.25 parts by weight of composite coupling agent diluted 12-18 times with anhydrous ethanol, maintaining the temperature and stirring for 10-25 min to obtain the composite inorganic filler.

[0008] Furthermore, the composite coupling agent is composed of tetramethylfluorourea hexafluorophosphate and aluminum zirconium coupling agent in a mass ratio of 1-1.5:1.2-1.6.

[0009] Furthermore, S3 specifically involves adding 18-24 parts by weight of the modified micro powder to a horizontal kneader and dry mixing it with the compounded inorganic filler at 20-25℃ and 250-400r / min for 15-25 minutes to obtain a dry mixture.

[0010] Furthermore, the preparation method of the modified micro powder is specifically as follows: A1. Weigh out 72-85 parts by weight of polyvinylidene fluoride, 10-14 parts by weight of carboxylated nitrile rubber, 0.8-1.3 parts by weight of silane coupling agent, and 0.1-0.3 parts by weight of antioxidant; A2. Mix polyvinylidene fluoride, carboxylated nitrile rubber and antioxidant at 20-25℃ and 220-310r / min for 2-3min, then add 0.2-0.4 parts of silane coupling agent and continue mixing for 3-5min to obtain a mixture; A3. The mixture is melt-blended and extruded into strips at 165-175℃ and 170-200r / min, cooled to room temperature by air, crushed at 1500-2000r / min for 3-5min, and passed through a 100-mesh sieve to obtain coarse blended powder; A4. Stir the coarse powder at 53-65℃ and 460-520r / min for 3-6min. During the stirring process, spray the remaining silane coupling agent with anhydrous ethanol diluted at 1:10. After stirring, dry at 75-80℃ for 1-1.5h and pass through a 200-mesh sieve to obtain the modified micro powder.

[0011] Furthermore, S4 specifically involves adding 28-36 parts of propylene glycol methyl ether to the dry mixture, dispersing it at 1000-1500 r / min for 25-40 min, and then milling it in a sand mill at 2000-2800 r / min for 18-30 min to obtain the basic slurry.

[0012] Furthermore, S5 specifically involves: transferring the base slurry into a vacuum homogenizer, homogenizing it for 12-20 minutes at a vacuum of -0.07 to -0.05 MPa and a speed of 600-800 r / min, removing air bubbles, and then curing it in a sealed environment at 28-35℃ for 5-9 hours to obtain a fluorinated resin for 3D printing.

[0013] A fluorinated resin for 3D printing prepared according to the method.

[0014] Compared with the prior art, the beneficial effects of this invention are as follows: 1. This invention utilizes a graded compounding process of rutile titanium dioxide and quartz powder, combined with calcium copper titanate and a composite coupling agent to prepare a compound inorganic filler. This effectively controls the crystallization behavior of polyvinylidene fluoride, resulting in a volume shrinkage rate of less than 2.12% and a warpage as low as 1.51% after molding of the fluorinated resin for 3D printing. This significantly improves the dimensional accuracy and molding stability of 3D printed products.

[0015] 2. This invention modifies polyvinylidene fluoride (PVDF) by melt blending with carboxylated nitrile rubber and then prepares modified micropowder through stepwise grafting with silane coupling agents. This effectively improves the interfacial bonding defects caused by the low surface energy of PVDF. At the same time, relying on the interfacial bonding effect between the compounded inorganic filler and the organic matrix, the mechanical properties of the material are synergistically improved. The tensile strength of the fluorinated resin 3D printed products is stable above 42 MPa and the flexural strength is above 51 MPa, which can meet the requirements of load-bearing components and high reliability conditions in the fields of chemical, electronic, and new energy industries for the mechanical properties of materials. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, a clear and complete description will be provided below in conjunction with the technical solutions of the embodiments of the present invention. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0017] Example 1: This example provides a method for preparing fluorinated resin for 3D printing, including the following steps: S1: Rutile titanium dioxide (micron-sized) and quartz powder (1250 mesh) were dried at 80℃ for 2 hours and then subjected to airflow classification to obtain ultrafine phase D. 50 =0.15-0.5μm, medium-fine phase D 50 =1.0-1.8μm, coarse-grained phase D 50 Powder with a particle size of 2.2-3.0 μm was mixed with ultrafine, medium-fine and coarse-grained powders at a mass ratio of 3:2:1 to obtain pretreated rutile titanium dioxide powder and pretreated quartz powder. S2: By weight, add 4 parts of calcium copper titanate (500nm), 12 parts of pretreated rutile titanium dioxide powder and 6 parts of pretreated quartz powder to a mixer, stir at 400r / min and heat to 65℃, add 0.08 parts of composite coupling agent diluted 12 times with anhydrous ethanol and spray it in, keep warm and stir for 10min to obtain the composite inorganic filler; The composite coupling agent is composed of tetramethylfluorourea hexafluorophosphate and aluminum zirconium coupling agent (LD-139) in a mass ratio of 1:1.2. S3: By weight, 18 parts of modified micro powder were added to a horizontal kneader and dry-mixed with the compound inorganic filler at 20℃ and 250r / min for 15min to obtain a dry mixture. The modified micro powder is prepared by: A1. Weigh out 72 parts by weight of polyvinylidene fluoride, 10 parts by weight of carboxylated nitrile rubber (item number HH2240JKTFLV), 0.8 parts by weight of silane coupling agent JH-N313 (propyltrimethoxysilane), and 0.1 parts by weight of antioxidant (1010). A2. Mix polyvinylidene fluoride, carboxylated nitrile rubber and antioxidant at 20℃ and 220r / min for 2min, then add 0.2 parts of silane coupling agent and continue mixing for 3min to obtain a mixture; A3. The mixture is melt-blended and extruded into strips at 165℃ and 170r / min, cooled to room temperature by air, crushed at 1500r / min for 3min, and passed through a 100-mesh sieve to obtain coarse blended powder; A4. Stir the coarse powder at 53℃ and 460r / min for 3min. During the stirring process, dilute the remaining silane coupling agent with anhydrous ethanol at a ratio of 1:10 and spray it in. After stirring, dry at 75℃ for 1h and pass through a 200-mesh sieve to obtain modified micro powder. S4: Add 28 parts of propylene glycol methyl ether to the dry mixture, disperse at 1000 r / min for 25 min, and then grind in a sand mill at 2000 r / min for 18 min to obtain the basic slurry; S5: Transfer the base slurry into a vacuum homogenizer and homogenize it for 12 minutes at a vacuum of -0.07MPa and 600r / min. After removing air bubbles, cure it in a sealed container at 28℃ for 5 hours to obtain a fluorinated resin for 3D printing.

[0018] Example 2: This example provides a method for preparing a fluorinated resin for 3D printing, including the following steps: S1: Rutile titanium dioxide (micron-sized) and quartz powder (1250 mesh) were dried at 95℃ for 3.5 h and then subjected to airflow classification to obtain ultrafine phase D. 50 =0.15-0.5μm, medium-fine phase D 50 =1.0-1.8μm, coarse-grained phase D 50 Powder with a particle size of 2.2-3.0 μm was mixed with ultrafine, medium-fine and coarse-grained powders in a mass ratio of 4:3:2 to obtain pretreated rutile titanium dioxide powder and pretreated quartz powder. S2: By weight, add 7 parts of calcium copper titanate (500nm), 18 parts of pretreated rutile titanium dioxide powder and 10 parts of pretreated quartz powder to a mixer, stir at 600r / min and heat to 80℃, add 0.25 parts of composite coupling agent diluted 18 times with anhydrous ethanol by spray, keep warm and stir for 25min to obtain the composite inorganic filler; The composite coupling agent is composed of tetramethylfluorourea hexafluorophosphate and aluminum zirconium coupling agent (LD-139) in a mass ratio of 1.5:1.6. S3: By weight, 24 parts of modified micro powder were added to a horizontal kneader and dry-mixed with the compound inorganic filler at 25℃ and 400r / min for 25min to obtain a dry mixture; The modified micro powder is prepared by: A1. Weigh out 85 parts by weight of polyvinylidene fluoride, 14 parts by weight of carboxylated nitrile rubber (item number HH2240JKTFLV), 1.3 parts by weight of silane coupling agent JH-N313 (propyltrimethoxysilane), and 0.3 parts by weight of antioxidant (1010). A2. Mix polyvinylidene fluoride, carboxylated acrylonitrile rubber and antioxidant at 25°C and 310 r / min for 3 min, then add 0.4 parts of silane coupling agent and continue mixing for 5 min to obtain a mixture; A3. The mixture is melt-blended and extruded into strips at 175℃ and 200r / min, cooled to room temperature by air, crushed at 2000r / min for 5min, and passed through a 100-mesh sieve to obtain coarse blended powder; A4. Stir the coarse powder at 520 r / min at 65℃ for 6 min. During the stirring process, dilute the remaining silane coupling agent with anhydrous ethanol at a ratio of 1:10 and spray it in. After stirring, dry at 80℃ for 1.5 h and pass through a 200 mesh sieve to obtain modified micro powder. S4: Add 36 parts of propylene glycol methyl ether to the dry mixture, disperse at 1500 r / min for 40 min, and then grind in a sand mill at 2800 r / min for 30 min to obtain the basic slurry; S5: Transfer the base slurry into a vacuum homogenizer and homogenize it for 20 minutes at a vacuum of -0.05 MPa and 800 r / min. After removing air bubbles, cure it in a sealed environment at 35°C for 9 hours to obtain a fluorinated resin for 3D printing.

[0019] Example 3: This example provides a method for preparing fluorinated resin for 3D printing, including the following steps: S1: Rutile titanium dioxide (micron-sized) and quartz powder (1250 mesh) were dried at 88℃ for 3 hours and then subjected to airflow classification to obtain ultrafine phase D. 50 =0.15-0.5μm, medium-fine phase D 50 =1.0-1.8μm, coarse-grained phase D 50 Powder with a particle size of 2.2-3.0 μm was mixed with ultrafine, medium-fine and coarse-grained powders at a mass ratio of 3:2:1 to obtain pretreated rutile titanium dioxide powder and pretreated quartz powder. S2: By weight, add 6 parts of calcium copper titanate (500nm), 15 parts of pretreated rutile titanium dioxide powder and 7 parts of pretreated quartz powder to a mixer, stir at 450r / min and heat to 70℃, add 0.14 parts of composite coupling agent diluted 15 times with anhydrous ethanol by spray, keep warm and stir for 20min to obtain the composite inorganic filler; The composite coupling agent is composed of tetramethylfluorourea hexafluorophosphate and aluminum zirconium coupling agent (LD-139) in a mass ratio of 1.2:1.3. S3: By weight, 22 parts of modified micro powder were added to a horizontal kneader and dry-mixed with the compound inorganic filler at 25℃ and 300r / min for 20min to obtain a dry mixture; The modified micro powder is prepared by: A1. Weigh out 80 parts by weight of polyvinylidene fluoride, 11 parts by weight of carboxylated acrylonitrile rubber (item number HH2240JKTFLV), 1.1 parts by weight of silane coupling agent JH-N313 (propyltrimethoxysilane), and 0.2 parts by weight of antioxidant (1010). A2. Mix polyvinylidene fluoride, carboxylated nitrile rubber and antioxidant at 25°C and 302 r / min for 2 min, then add 0.2 parts of silane coupling agent and continue mixing for 5 min to obtain a mixture; A3. The mixture is melt-blended and extruded into strips at 172℃ and 200r / min, cooled to room temperature by air, crushed at 1500r / min for 5min, and passed through a 100-mesh sieve to obtain coarse blended powder; A4. Stir the coarse powder at 500 r / min for 5 min at 60℃. During the stirring process, spray the remaining silane coupling agent with anhydrous ethanol diluted at 1:10. After stirring, dry at 78℃ for 1.5 h and pass through a 200 mesh sieve to obtain modified micro powder. S4: Add 31 parts of propylene glycol methyl ether to the dry mixture, disperse at 1200 r / min for 30 min, and then grind in a sand mill at 2500 r / min for 20 min to obtain the basic slurry; S5: Transfer the base slurry into a vacuum homogenizer and homogenize it for 20 minutes at a vacuum of -0.07MPa and 680r / min. After removing air bubbles, cure it in a sealed container at 30℃ for 5 hours to obtain a fluorinated resin for 3D printing.

[0020] Comparative Example 1: This comparative example differs from Example 3 in that, in S1, the particle size of both rutile titanium dioxide (micron-sized) and quartz powder is reduced to medium to fine phases, i.e., D. 50 =1.0-1.8μm.

[0021] Comparative Example 2: The difference between this comparative example and Example 3 is that, in the preparation of the modified micro powder, the carboxylated butadiene nitrile rubber was replaced with an equal mass of perfluoroether rubber (item number xyh001).

[0022] Comparative Example 3: The difference between this comparative example and Example 3 is that in S2, the composite coupling agent is composed of tetramethylfluorourea hexafluorophosphate and aluminum zirconium coupling agent (LD-139) in a mass ratio of 3:1.

[0023] Preparation example: The fluorinated resins for 3D printing prepared in each example and comparative example were used to prepare standard test samples by fused deposition modeling (FDM) 3D printing process. The printing parameters were: nozzle temperature 210℃, printing platform temperature 80℃, layer thickness 0.15mm, printing speed 30mm / s (outer wall), 60mm / s (fill), filling method was linear filling, and molding chamber temperature 40℃.

[0024] The printed blank was placed in a vacuum drying oven and dried at 90℃ and a vacuum of -0.06MPa for 3 hours to eliminate the internal stress generated during the printing process and to fully fuse the incompletely melted resin micro-regions inside the sample, thereby improving density. After heating, it was allowed to cool naturally to room temperature in the oven. First, it was coarsely sanded with 400-grit wet sandpaper to remove obvious burrs and overflow; then it was finely sanded with 1000-grit wet sandpaper to remove the coarse sanding marks; finally, it was finely sanded with 2000-grit wet sandpaper.

[0025] Experimental Example 1: Detection of volume shrinkage rate; Print a standard cuboid sample (length × width × height = 50mm × 50mm × 10mm) and record the theoretical volume V0 of the 3D model design. After post-processing, place the sample in an environment of 23℃±2℃ and 50%±5% relative humidity for 24 hours. Measure the actual length, width, and height of the sample using a digital caliper with an accuracy of 0.001mm and calculate the actual volume V1. The volume shrinkage rate S = (V0-V1) / V0×100%, and take the average value of 5 parallel samples as the test result.

[0026] Experimental Example 2: Determination of warpage; Print a standard flat plate sample (length × width × thickness = 100mm × 100mm × 2mm), and after post-processing, place it in a standard environment (23℃±2℃, 50%±5%RH) for 24 hours; use a laser warp measuring instrument to place the sample on a horizontal testing platform, scan the vertical distance between the four corners and the center of the sample and the horizontal platform, and record the maximum warp height H (unit: mm); warp W = H / sample side length (100mm) × 100%, and take the average value of 5 parallel samples as the test result.

[0027] Experimental Example 3: Tensile strength (MPa) was tested according to GB / T 1040 "Determination of Tensile Properties of Plastics".

[0028] Experimental Example 4: The bending strength (MPa) was tested according to GB / T 9341 "Determination of bending properties of plastics".

[0029] The results are shown in the table below: project Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Volume shrinkage rate % 2.12 2.08 2.09 2.56 3.74 2.34 Warpage % 1.45 1.48 1.51 3.86 1.87 2.23 Tensile strength (MPa) 42.37 42.66 42.19 41.86 37.22 36.84 Bending strength (MPa) 51.79 52.14 51.96 48.11 47.36 50.02 As shown in the table above, the volume shrinkage rate of the embodiments is between 2.08% and 2.12%, the warpage is maintained between 1.45% and 1.51%, and the tensile strength and flexural strength are stable at 42MPa and 51MPa respectively. This indicates that the fluorinated resin prepared by the present invention has the characteristics of low shrinkage and low warpage, and excellent mechanical properties.

[0030] Comparative Example 1, which retains only the medium and fine phase particles of rutile titanium dioxide and quartz powder, shows that its volume shrinkage rate increases to 2.56% and its warpage increases significantly to 3.86%. This indicates that the treatment method of classifying inorganic powders into ultrafine, medium-fine, and coarse phases and compounding them in a specific mass ratio can effectively reduce the volume shrinkage during resin molding and reduce the generation of internal stress through the close packing effect of powders of different particle sizes, thereby suppressing warpage deformation.

[0031] In Comparative Example 2, after replacing the carboxylated nitrile rubber in the modified micropowder with an equal mass of perfluoroether rubber, the volume shrinkage rate increased sharply to 3.74%, while the tensile strength and flexural strength decreased to 37.22 MPa and 47.36 MPa, respectively. This indicates that the carboxylated nitrile rubber has better compatibility with polyvinylidene fluoride (PVDF). In the modified micropowder, it can effectively regulate the crystallization behavior of PVDF, reduce crystallinity and volume shrinkage rate, and improve the interfacial bonding force of the material, thereby ensuring mechanical properties. Perfluoroether rubber, on the other hand, cannot achieve this modification effect.

[0032] After adjusting the ratio of the composite coupling agent in Comparative Example 3 to 3:1, all properties deteriorated to varying degrees. The volume shrinkage rate and warpage increased, and the tensile strength dropped significantly to 36.84 MPa. This indicates that the composite coupling agent with the ratio specified in this invention can effectively improve the interfacial bonding performance between the inorganic filler and the matrix, and improve the dispersibility of the filler in the matrix. If the ratio is unbalanced, it will lead to a decrease in interfacial bonding force, which will not only increase the risk of shrinkage and warpage of the product, but also reduce the mechanical properties of the material.

[0033] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a fluorinated resin for 3D printing, characterized in that, Includes the following steps: S1: Ultrafine phase D was prepared by drying rutile titanium dioxide and quartz powder and then classifying them by airflow separation. 50 =0.15-0.5μm, medium-fine phase D 50 =1.0-1.8μm, coarse-grained phase D 50 Powder with a particle size of 2.2-3.0 μm was mixed with ultrafine, medium-fine and coarse-grained powders at a mass ratio of 3-4:2-3:1-2 to obtain pretreated rutile titanium dioxide powder and pretreated quartz powder. S2: By weight, add 4-7 parts of calcium copper titanate, 12-18 parts of pretreated rutile titanium dioxide powder and 6-10 parts of pretreated quartz powder to a mixer, stir and heat, and spray in 0.08-0.25 parts of composite coupling agent diluted with anhydrous ethanol, and stir to obtain the composite inorganic filler. S3: By weight, 18-24 parts of modified micro powder and compound inorganic filler are dry-mixed to obtain dry mixture; S4: Add 28-36 parts of propylene glycol methyl ether to the dry mixture for dispersion, and then sand mill to obtain the basic slurry; S5: Vacuum homogenize and degas the base slurry, and then cure it in a sealed environment to obtain a fluorinated resin for 3D printing. The modified micro powder is prepared by: Weigh out 72-85 parts by weight of polyvinylidene fluoride, 10-14 parts by weight of carboxylated nitrile rubber, 0.8-1.3 parts by weight of silane coupling agent, and 0.1-0.3 parts by weight of antioxidant. Polyvinylidene fluoride, carboxylated nitrile rubber and antioxidant are stirred, and then 0.2-0.4 parts of silane coupling agent are added and stirred to obtain a mixture; the mixture is melt-blended and extruded at 165-175℃, cooled, crushed and sieved to obtain a coarse blended powder; the coarse blended powder is stirred, and the remaining silane coupling agent is added during the stirring process; it is dried and sieved to obtain modified micro powder.

2. The method for preparing fluorinated resin for 3D printing according to claim 1, characterized in that, S2 is specifically as follows: By weight, 4-7 parts of calcium copper titanate, 12-18 parts of pretreated rutile titanium dioxide powder and 6-10 parts of pretreated quartz powder are added to a mixer, stirred at 400-600 r / min and heated to 65-80℃. 0.08-0.25 parts of composite coupling agent are diluted 12-18 times with anhydrous ethanol and sprayed in. The mixture is kept warm and stirred for 10-25 min to obtain the composite inorganic filler.

3. The method for preparing fluorinated resin for 3D printing according to claim 1, characterized in that, The composite coupling agent is composed of tetramethylfluorourea hexafluorophosphate and aluminum zirconium coupling agent in a mass ratio of 1-1.5:1.2-1.

6.

4. The method for preparing fluorinated resin for 3D printing according to claim 1, characterized in that, S3 specifically involves adding 18-24 parts by weight of the modified micro powder to a horizontal kneader and dry mixing it with the compounded inorganic filler at 20-25℃ and 250-400r / min for 15-25 minutes to obtain a dry mixture.

5. The method for preparing fluorinated resin for 3D printing according to claim 1, characterized in that, The specific method for preparing the modified micro powder is as follows: A1. Weigh out 72-85 parts by weight of polyvinylidene fluoride, 10-14 parts by weight of carboxylated nitrile rubber, 0.8-1.3 parts by weight of silane coupling agent, and 0.1-0.3 parts by weight of antioxidant; A2. Mix polyvinylidene fluoride, carboxylated nitrile rubber and antioxidant at 20-25℃ and 220-310r / min for 2-3min, then add 0.2-0.4 parts of silane coupling agent and continue mixing for 3-5min to obtain a mixture; A3. The mixture is melt-blended and extruded into strips at 165-175℃ and 170-200r / min, cooled to room temperature by air, crushed at 1500-2000r / min for 3-5min, and passed through a 100-mesh sieve to obtain coarse blended powder; A4. Stir the coarse powder at 53-65℃ and 460-520r / min for 3-6min. During the stirring process, spray the remaining silane coupling agent with anhydrous ethanol diluted at 1:

10. After stirring, dry at 75-80℃ for 1-1.5h and pass through a 200-mesh sieve to obtain the modified micro powder.

6. The method for preparing fluorinated resin for 3D printing according to claim 1, characterized in that, S4 specifically involves adding 28-36 parts of propylene glycol methyl ether to the dry mixture, dispersing it at 1000-1500 r / min for 25-40 min, and then grinding it in a sand mill at 2000-2800 r / min for 18-30 min to obtain the basic slurry.

7. The method for preparing fluorinated resin for 3D printing according to claim 1, characterized in that, S5 specifically involves transferring the base slurry into a vacuum homogenizer and homogenizing it for 12-20 minutes at a vacuum of -0.07 to -0.05 MPa and a speed of 600-800 r / min. After removing air bubbles, the slurry is then cured in a sealed environment at 28-35℃ for 5-9 hours to obtain a fluorinated resin for 3D printing.

8. A fluorinated resin for 3D printing prepared by the method according to any one of claims 1-7.