A method for improving mechanical properties of 3D printed elastomeric polymer materials using an oxygen-free environment

Abstract

The application discloses a method for improving mechanical properties of 3D printing elastomer polymer material by using an oxygen-free environment, and belongs to the technical field of 3D printing.The method comprises the following steps: adding anaerobic materials into the elastomer polymer, mixing the elastomer polymer with the anaerobic materials to obtain a composite material, and improving the interlayer bonding strength by using an oxygen-free environment condition, so that the performance of resisting external force deformation is improved, and the overall performance of the elastomer polymer part is improved.

Description

Technical Field

[0001] This invention relates to the field of 3D printing technology, and in particular to a method for improving the mechanical properties of 3D printed elastomer polymer materials using an oxygen-free environment. Background Technology

[0002] Fused Deposition Modeling (FDM) is a common and early commercial 3D printing technology. It uses filamentary solid material, extruding molten thermoplastic polymer into a filament, which is then deposited onto a platform by controlling the movement of a machine tool, building up layer by layer to form a 3D object. The FDM filament is fed through drive wheels and heated to a semi-fluid state by a heater. The molten filament is then ejected through a nozzle and deposited onto the worktable used to construct the part. Because the material is extruded into a semi-fibrous state, it remains fused with the surrounding material already deposited. The nozzle then moves in the XY plane and begins depositing material according to the cross-sections of the part's STL file. When one cross-section is complete, the printing platform moves vertically downwards in the Z direction to begin depositing a new layer. After a period of time, typically several hours, the original CAD file can be transformed into a complete solid object.

[0003] Due to the extrusion and forming characteristics of materials during FDM printing, certain complex shapes or objects requiring high detail may face limitations and challenges. FDM technology involves direct exposure to the external environment and uses a layer-by-layer printing method, resulting in temperature differences between newly printed layers and the lack of interlayer compressive strength. Consequently, the resulting material exhibits poor interlayer bonding, leading to significantly different mechanical properties compared to traditional manufacturing methods. Elastomer polymers such as polyamide (PA) and thermoplastic polyurethane (TPU) are common printing materials in FDM technology. They possess numerous advantages, including lightweight, good mechanical properties, corrosion resistance, high-temperature resistance, and ease of modification. Their brittle temperature can reach -120℃, making them promising candidates for further application in 3D printing. FDM-printed elastomeric polymer products also require further post-processing to improve their mechanical properties and better suit their applications. Therefore, 3D-printed elastomeric polymer products require further post-processing to enhance their mechanical properties.

[0004] Anaerobic materials are added to elastomeric polymers in an anaerobic environment. The anaerobic environment meets the conditions for curing anaerobic materials in elastomeric polymers, and oxidative degradation does not occur under vacuum conditions, thus avoiding the performance degradation caused by oxidative degradation. Compared with fiber-reinforced composites, the anaerobic environment modification method for elastomeric polymers can save materials and reduce the difficulty of post-processing. Summary of the Invention

[0005] This invention provides a method for improving the mechanical properties of 3D printed elastomer polymer materials using an oxygen-free environment. By modifying the elastomer polymer in an oxygen-free environment, the density and mechanical properties of FDM printed parts are improved, providing research ideas and valuable technical experience for the development and application of 3D printing technology.

[0006] To achieve the above-mentioned objectives, the present invention provides the following solution:

[0007] S1 involves drying the elastomeric polymer particles in a vacuum drying oven at a temperature of 50℃–100℃ for 4–8 hours. To prepare a composite material, the elastomeric polymer particles are dissolved in an organic solvent at 60℃–120℃, and then the anaerobic material is added and stirred, maintaining the anaerobic material at 0.5–5 wt.% of the elastomeric polymer content. The solution is then mixed and left to stand overnight. The mixture is then vacuum-dried into granules at 50℃–100℃, extruded in an extruder, and stretched into filaments. The filament diameter is controlled by adjusting the screw speed and the filament traction speed of the traction machine, thus preparing the polymer composite filament. Depending on the printing requirements, the diameter of the composite filament ranges from 1.75 mm to 3.00 mm. The stretched filament is then wound onto a roller and used directly in an FDM printer for printing.

[0008] S2 imports the STL format model data into the slicing software and sets the FDM printing parameters: number of nozzles is set to 1; nozzle temperature is 15℃~250℃, nozzle diameter is 0.2mm~1.2mm, substrate temperature is 45℃~100℃; printing speed is 10mm / s~100mm / s, X-axis movement speed is 30mm / s~120mm / s, Y-axis movement speed is 30mm / s~120mm / s, Z-axis movement speed is 10mm / s~120mm / s, extrusion ratio is 0.1~2, retraction distance is 0.5mm~5mm, retraction speed is 5mm / s~50mm / s, layer thickness is 0.05mm~0.4mm, and infill density is 50%~100%. After setting the parameters, slicing is performed, and a Gcode format file is obtained, which is then imported into a commercial FDM printer to start printing.

[0009] S3 simulates an oxygen-free environment. After printing, the anaerobic elastomer polymer parts are placed in a vacuum atmosphere furnace, the furnace door is closed, a vacuum environment is obtained using a vacuum pump, and the air inside the furnace is extracted using a vacuum pump to ensure that the absolute pressure inside the furnace is ≤51.3KPa. Protective gas is then introduced, and the air inlet valve is closed when the gas pressure inside the furnace reaches an absolute pressure of 91.3KPa~101.3KPa.

[0010] The S4 atmosphere furnace is set to maintain a vacuum environment for 10 to 240 minutes to perform anaerobic curing on the parts. After the curing is completed, air is introduced and the parts are removed.

[0011] The anaerobic curable composition comprises one or more of the following as monomer materials, in an amount between 90 and 95 wt.%: hydroxypropyl methacrylate, polyurethane dimethacrylate, acrylate, epoxy methacrylate, triethylene glycol dimethacrylate, 309 polyester, acrylic acid, triethylene glycol dimethacrylate, triethylene glycol dimethacrylate, dibasic acrylate, methacrylate, epoxy acrylate, epoxy acrylate, diacrylate, bisphenol A epoxy resin, methacrylate, E-44 epoxy methacrylate, and triethylene glycol dimethacrylate; and diethylene glycol dimethacrylate. One or more of the following—resin, phenolic resin, silicone sealant, and fluorosilicone sealant—are used as initiators to promote monomer polymerization, with a dosage between 0 and 5 wt.%. Polymethacrylate is used as a thickener to adjust the viscosity of the anaerobic resin, with a dosage between 0 and 5 wt.%. Sodium hypophosphite, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], pentaerythritol diphosphite (2,4-dicumylphenyl)phosphite, 2,6-di-tert-butyl-4-methylphenol, and 2,2'-methylenebis(4-methyl-6-tert-butylphenol) are used as antioxidants to extend the service life and performance of the anaerobic curing composition, with a dosage of 0 to 0.1 wt.% of the monomer material. The anaerobic curing composition comprises monomer material, initiator, and thickener, with a total content of 100%.

[0012] The slicing software used was Cura, Slic3r, PrusaSlicer, MatterControl, and Simplify3D.

[0013] The elastomer polymer is one or more of the following: acrylonitrile-butadiene-styrene copolymer (ABS), polycaprolactone carbonate (PCL), polyamide (PA), polyetheretherketone (PEEK), thermoplastic polyurethane (TPU), polylactic acid (PLA), ultra-high molecular weight polyethylene (UHMWPE), and polyvinyl chloride (PVC).

[0014] The strength of the selected anaerobic material is greater than the strength of the selected elastomer polymer. The protective gas is nitrogen or argon.

[0015] The beneficial effects of this invention are:

[0016] (1) Using an oxygen-free environment for anaerobic curing treatment can prevent the parts from oxidizing and ensure that the anaerobic curing process is fully carried out, which can save materials and reduce the difficulty of post-processing.

[0017] (2) Anaerobic curing eliminates the internal stress caused by temperature difference in the parts during the printing process, and also allows the internal grains of the elastomer polymer to grow secondary, fill the internal pores, and improve the density of the parts.

[0018] (3) The method used in this invention can significantly improve the mechanical properties of 3D printed elastomer polymer parts after anaerobic curing, increase the density of the elastomer polymer, and facilitate the widespread application of 3D printed elastomer polymer parts; the tensile strength of the mechanical properties is increased by 20% to 100%.

[0019] (4) The method described in this invention opens up a new way of thinking for enhancing the mechanical properties of 3D printed parts, and will provide research ideas and valuable technical experience for the development and application of 3D printing technology. Attached Figure Description

[0020] Figure 1 This is a flowchart of the process of this invention.

[0021] Figure 2 This is a diagram of the apparatus used in the process of this invention. Detailed Implementation

[0022] The present invention will now be described in detail with reference to specific embodiments. The description in this section is merely illustrative and explanatory, and should not be construed as limiting the scope of protection of the present invention.

[0023] Example 1

[0024] TPU granules were dried in a vacuum drying oven at 80°C for 4 hours. Composite materials were prepared by mixing anaerobic materials with different proportions of the elastomer polymer. TPU was selected as the elastomer polymer. TPU granules were dissolved in DMF at 150 mg / ml under stirring at 60°C, then the anaerobic material was added, and the mixture was stirred for 5 hours, followed by overnight mixing. The anaerobic curing composition was set to 0.5 wt.%, 2 wt.%, and 5 wt.% of the elastomer polymer content. The mixture was then vacuum dried at 60°C for 24 hours, then extruded and stretched into filaments. The screw speed and filament traction speed were adjusted to 30 rpm, controlling the filament diameter at 1.75 mm to prepare polymer composite filaments. The stretched filaments were wound onto rollers and directly used for printing in an FDM printer.

[0025] Import the STL format model data into the slicing software Simplify 3D. In Simplify 3D, set the FDM printing parameters as follows: nozzle temperature 220℃ (based on TPU material); nozzle printing speed 50mm / s; nozzle X-axis movement speed 60mm / s; nozzle Y-axis movement speed 60mm / s; nozzle Z-axis movement speed 30mm / s; nozzle extrusion ratio 1; layer thickness 0.1mm; infill density 100%. After setting the parameters, slice the product and obtain a Gcode format file. Import this file into a commercial FDM printer to begin printing.

[0026] After printing, place the TPU parts into a vacuum atmosphere furnace, close the furnace lid, and use a vacuum pump to extract the air from the vacuum atmosphere furnace to ensure that the absolute pressure inside the furnace is ≤51.3KPa; fill with argon gas, and close the gas inlet valve when the gas pressure inside the furnace reaches an absolute pressure of 101.3KPa; perform anaerobic curing treatment on the parts, and set the atmosphere furnace to maintain a vacuum environment for 240 minutes.

[0027] Then air is introduced, and the parts are removed.

[0028] The anaerobic curable composition comprises: polyethylene glycol dimethacrylate as a monomer material at an amount of 95 wt.%, tert-butyl peroxide benzoate as an initiator to promote monomer polymerization at an amount of 5 wt.%, and 2,6-di-tert-butyl-4-methylphenol as an antioxidant at an amount of 0.1 wt.% of the monomer material.

[0029] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for improving the mechanical properties of 3D-printed elastomer polymer materials using an oxygen-free environment, characterized in that... Includes the following steps: S1 involves drying the elastomer polymer particles in a vacuum drying oven at a temperature of 50℃~100℃ for 4~8 hours. A composite material is prepared by mixing the elastomer polymer with anaerobic material. The elastomer polymer particles are dissolved in an organic solvent at 60℃~120℃, and then the anaerobic material is added and stirred. The content of the anaerobic material is controlled at 0.5~5 wt.% of the elastomer polymer content. The solution is mixed and left overnight. The mixture is then vacuum-dried into granules at 50℃~100℃, extruded in an extruder, and stretched into filaments. The filament diameter is controlled by adjusting the screw speed and the filament traction speed of the traction machine, thus preparing polymer composite filaments. The diameter of the composite filaments ranges from 1.75mm to 3.00mm. The stretched filaments are wound onto a roller and directly used for printing in an FDM printer. S2 imports the STL format model data into the slicing software and sets the FDM printing parameters: number of nozzles is set to 1; nozzle temperature is 15℃~250℃, nozzle diameter is 0.2mm~1.2mm, substrate temperature is 45℃~100℃; printing speed is 10mm / s~100mm / s, X-axis movement speed is 30mm / s~120mm / s, Y-axis movement speed is 30mm / s~120mm / s, Z-axis movement speed is 10mm / s~120mm / s, extrusion ratio is 0.1~2, retraction distance is 0.5mm~5mm, retraction speed is 5mm / s~50mm / s, layer thickness is 0.05mm~0.4mm, and infill density is 50%~100%. After setting the parameters, slicing is performed, and a Gcode format file is obtained, which is then imported into a commercial FDM printer to start printing. S3 simulates an oxygen-free environment. After printing, the anaerobic elastomer polymer parts are placed in a vacuum atmosphere furnace, the furnace door is closed, a vacuum environment is obtained using a vacuum pump, and the air inside the furnace is extracted using a vacuum pump to ensure that the absolute pressure inside the furnace is ≤51.3KPa. Protective gas is then introduced, and the air inlet valve is closed when the gas pressure inside the furnace reaches an absolute pressure of 91.3KPa~101.3KPa. The S4 atmosphere furnace is set to maintain a vacuum environment for 10 to 240 minutes to perform anaerobic curing on the parts. After the curing is completed, air is introduced and the parts are removed.

2. The method for improving the mechanical properties of 3D-printed elastomer polymer materials using an oxygen-free environment as described in claim 1, characterized in that: The anaerobic materials include: hydroxypropyl methacrylate, polyurethane dimethacrylate, acrylate, epoxy methacrylate, triethylene glycol dimethacrylate, 309 polyester, acrylic acid, triethylene glycol dimethacrylate, triethylene glycol dimethacrylate, dibasic acrylate, methacrylate epoxy acrylate, acrylate epoxy ester, diacrylate, bisphenol A epoxy resin, methacrylate, E-44 epoxy methacrylate, and triethylene glycol dimethacrylate as monomer materials, with a dosage between 90 and 95 wt.%; one or more of diethylenediamine (DEA), xyleneamine (DMTA), phenolic resin, phenolic adhesive, silicone adhesive, and fluorosilicone adhesive as initiators to promote monomer polymerization, with a dosage between 0 and 5 wt.%; and polymethacrylate as a thickener to adjust the viscosity of the anaerobic resin, with a dosage between 0 and 5 wt.%. Between wt.%; sodium hypophosphite, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], bis(2,4-dicumylphenyl)pentaerythritol diphosphite, 2,6-di-tert-butyl-4-methylphenol, and 2,2'-methylenebis(4-methyl-6-tert-butylphenol) are used as antioxidants to extend the service life and performance of the anaerobic curing composition, with a dosage of 0~0.1 wt.% of the monomer material; the anaerobic curing composition includes monomer material, initiator, and thickener, with a total content of 100% for all three components.

3. The method for improving the mechanical properties of 3D-printed elastomer polymer materials using an oxygen-free environment as described in claim 1, characterized in that: The slicing software used was Cura, Slic3r, PrusaSlicer, MatterControl, and Simplify3D.

4. The method for improving the mechanical properties of 3D printed elastomer polymer materials using an oxygen-free environment as described in claim 1, characterized in that: The elastomer polymer is one or more of the following: acrylonitrile-butadiene-styrene copolymer (ABS), polycaprolactone carbonate (PCL), polyamide (PA), polyetheretherketone (PEEK), thermoplastic polyurethane (TPU), polylactic acid (PLA), ultra-high molecular weight polyethylene (UHMWPE), and polyvinyl chloride (PVC).

5. The method for improving the mechanical properties of 3D printed elastomer polymer materials using an oxygen-free environment as described in claim 1, characterized in that: The protective gas is nitrogen or argon.

6. The method for improving the mechanical properties of 3D printed elastomer polymer materials using an oxygen-free environment as described in claim 1, characterized in that: The strength of the anaerobic material is greater than the strength of the selected elastomer polymer.

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