Copper-nickel-iron alloy electromagnetic absorption ink for 3D printing and preparation method of copper-nickel-iron alloy electromagnetic absorption ink

Abstract

The invention relates to copper-nickel-iron alloy electromagnetic absorption ink for 3D printing and a preparation method of the copper-nickel-iron alloy electromagnetic absorption ink, and belongs to the field of ink processing. The copper-nickel-iron alloy electromagnetic absorption ink is prepared from the following raw materials in parts by mass: 5 to 13.5 parts of a copper-nickel-iron alloy electromagnetic absorbent, 37 to 50.5 parts of hyperbranched polyacrylate resin, 32.5 to 46.5 parts of organic silicon modified polyurethane acrylate, 6 to 13.5 parts of acryloylmorpholine, 2.2 to 5.3 parts of a photoinitiator, 0.6 to 2.3 parts of a de-foaming agent, 0.6 to 2.8 parts of a dispersing agent and 1.5 to 3.5 parts of a surfactant. The ink disclosed by the invention adopts copper-nickel-iron alloy as an electromagnetic absorbent, so that the electromagnetic wave absorption capacity of the material is greatly improved, and the ink has a relatively wide absorption frequency band. The cured material has high wear resistance, stable physical and chemical properties at high temperature, and is not easy to deform, and can be applied to rapid manufacturing of high-precision electromagnetic absorbers with different shapes in military and civil fields.

Description

Technical Field

[0001] The present invention relates to the field of ink processing, and more particularly, to a copper-nickel-iron alloy electromagnetic absorption ink for 3D printing and a preparation method thereof, and more particularly to a copper-nickel-iron alloy electromagnetic absorption ink for ultraviolet light-curing 3D printing and a preparation method thereof. Background Art

[0002] With the development of modern science and technology, electromagnetic radiation has become an inevitable source of pollution, and its impact on human production and life is increasing day by day. Military and civilian electronic instruments are becoming more and more miniaturized, and higher requirements are put forward for the precision of equipment, the stability of instruments, the security of data, etc. The interference of electromagnetic radiation on electronic instruments will affect the normal operation of space exploration equipment, military machines, scientific equipment, surveillance cameras, etc. Electromagnetic radiation may also pose a threat to human health. For example, long-term exposure to electromagnetic radiation will increase the risk of cancer, heart disease, skin diseases and many other diseases. Electromagnetic absorption materials are materials that can convert the incident harmful electromagnetic wave energy into other forms of energy and dissipate it, and are rarely reflected back.

[0003] Polymer-based electromagnetic absorption materials have the advantages of high flexibility, good corrosion resistance, low cost, good processing performance, etc., and can better meet the needs of fields such as aerospace and electronic communication, showing great advantages in the field of electromagnetic absorption materials. At present, when preparing polymer-based electromagnetic absorbers by 3D printing, mainly fused deposition modeling (FDM) type 3D printers are used, and the printing accuracy of this type of printer is not high (generally the accuracy is 500 μm). UV light-curing molding (DLP, SLA type) is one of the 3D printing methods with the highest accuracy (generally the accuracy is 10 μm). It cures and forms through the chain polymerization reaction of monomers and prepolymers in the resin initiated by ultraviolet light. By selecting UV light-curing resin as the matrix material and filling with electromagnetic absorption agents to prepare electromagnetic absorption ink, and using UV light-curing 3D printing for printing, various complex-shaped and high-precision electromagnetic absorbers can be quickly designed and printed, expanding the application range of electromagnetic absorption materials.

[0004] At present, polymer-based electromagnetic absorbers are mainly formed by die casting and calendering. The process is complex, the production cycle is long, and the accuracy is poor. 3D printing technology, also known as 3D rapid prototyping technology, is an additive manufacturing technology. First, the model structure is designed using 3D modeling software in a computer, and then a 3D object with a complex structure is quickly manufactured through precise 3D stacking and forming. In some literature, a fused deposition modeling (FDM) type 3D printer is used to prepare electromagnetic absorption materials, but the printing accuracy of this printer is not high (generally 500 μm). The electromagnetic absorbers added are mainly carbon materials (electric loss materials) and magnetic metal oxide materials (magnetic loss materials). The electromagnetic wave absorption width is relatively narrow, the mechanical strength of the materials is poor, they are not wear-resistant, are prone to fracture, and are prone to deformation at high temperatures. Summary of the Invention

[0005] In view of this, in order to solve the above-mentioned many technical problems, the present invention provides a copper-nickel-iron alloy electromagnetic absorption ink suitable for ultraviolet light-curing 3D printing and a preparation method thereof.

[0006] The first object of the present invention is to provide a copper-nickel-iron alloy electromagnetic absorption ink suitable for ultraviolet light-curing 3D printing. By using hyperbranched polyacrylate resin, organosilicon-modified polyurethane acrylate, and acryloylmorpholine in combination, the resins in the formula have good mutual compatibility, no delamination phenomenon, and enhance the wetting effect on the copper-nickel-iron alloy. At the same time, it has good stability, fluidity, and rapid curing and forming performance. When added to a light-curing 3D printer, the ink can meet the printing requirements. After curing and forming, it has good dimensional stability, high mechanical strength, stable physical and chemical properties under high-temperature conditions, is not easy to deform, has very strong electromagnetic absorption ability, and a relatively wide absorption band. It can be applied to the rapid manufacturing of electromagnetic absorbers with various shapes and high precision in military and civilian fields.

[0007] The second object of the present invention is to provide a preparation method for the above-mentioned copper-nickel-iron alloy electromagnetic absorption ink suitable for ultraviolet light-curing 3D printing. The preparation method has the advantages of being able to completely retain the effective components of the raw materials, and is simple and easy to operate, with closely connected front and back steps, and mild operating conditions.

[0008] In order to achieve the above objects of the present invention, the following technical solutions are adopted:

[0009] A copper-nickel-iron alloy electromagnetic absorption ink for 3D printing is mainly prepared from the following raw materials: by mass fraction, 5-13.5 parts of copper-nickel-iron alloy electromagnetic absorber, 37-50.5 parts of hyperbranched polyacrylate resin, 32.5-46.5 parts of organosilicon-modified polyurethane acrylate, 6-13.5 parts of acryloylmorpholine, 2.2-5.3 parts of photoinitiator, 0.6-2.3 parts of defoamer, 0.6-2.8 parts of dispersant, and 1.5-3.5 parts of surfactant.

[0010] To further optimize the raw material formula, the amounts of raw materials are as follows: 9.6 - 11.3 parts of copper-nickel-iron alloy electromagnetic absorber, 42.6 - 47.6 parts of hyperbranched polyacrylate resin, 35.4 - 38.2 parts of organosilicon-modified polyurethane acrylate, 8.8 - 10.2 parts of acryloylmorpholine, 2.6 - 3.1 parts of photoinitiator, 1.2 - 1.4 parts of defoamer, 0.8 - 1.5 parts of dispersant, and 2.1 - 2.6 parts of surfactant.

[0011] In addition, the amounts of raw materials can also be: 6.5 - 9.2 parts of copper-nickel-iron alloy electromagnetic absorber, 46 - 49.4 parts of hyperbranched polyacrylate resin, 39.5 - 45.6 parts of organosilicon-modified polyurethane acrylate, 8.2 - 11.6 parts of acryloylmorpholine, 3.4 - 4.6 parts of photoinitiator, 1.1 - 2.1 parts of defoamer, 1.4 - 2.3 parts of dispersant, and 1.9 - 2.8 parts of surfactant.

[0012] More preferably, 7.8 - 8.6 parts of copper-nickel-iron alloy electromagnetic absorber, 47.2 - 49.2 parts of hyperbranched polyacrylate resin, 42.6 - 45.1 parts of organosilicon-modified polyurethane acrylate, 9.2 - 10.6 parts of acryloylmorpholine, 3.8 - 4.4 parts of photoinitiator, 1.5 - 2 parts of defoamer, 1.6 - 2 parts of dispersant, and 2.1 - 2.6 parts of surfactant.

[0013] Among them, for the copper-nickel-iron alloy electromagnetic absorber, by mass percentage, the nickel content is 38 - 42%, the copper content is 28 - 32%, and the iron content is 26 - 34%. The copper-nickel-iron alloy electromagnetic absorber is in powder form, and the powder particle size ≤ 50 microns. The copper-nickel-iron alloy electromagnetic absorber used has the characteristics of fine particles, strong electromagnetic loss ability, wide electromagnetic absorption frequency band, acid and alkali resistance, light and heat resistance, stable chemical properties, and good resin affinity. Copper-nickel-iron alloy is a special soft magnetic alloy, which has high magnetic permeability and magnetic hysteresis loss, high corrosion resistance and excellent mechanical properties, good thermal stability, and certain electrical conductivity. Using copper-nickel-iron alloy as an electromagnetic absorber and adding it to the UV-curable resin to prepare copper-nickel-iron alloy electromagnetic absorption ink has a synergistic electromagnetic wave dissipation effect of magnetic loss and electrical loss, and can greatly improve the electromagnetic wave absorption ability of the material.

[0014] The degree of branching of the hyperbranched polyacrylate resin is 0.5 - 0.9, the molecular weight is 1500 - 10000, the appearance is light yellow or colorless transparent viscous liquid, and the viscosity is 8 - 10 Pa·s.

[0015] The organosilicon-modified polyurethane acrylate has 3 - 6 functional groups, the molecular weight is 15000 - 20000, the appearance is light yellow or colorless transparent viscous liquid, and the viscosity is 20 - 50 Pa·s.

[0016] Through modification treatment, the two resins have a good wetting effect on the electromagnetic absorber, and at the same time have the characteristics of fast curing speed, strong wear resistance and high mechanical strength, can meet the grinding performance and printing performance of the ink, and the ink using organosilicon-modified polyurethane acrylate and hyperbranched polyacrylate resin can be printed on an ultraviolet-curing 3D printer (DLP, SLA type), which can significantly improve the curing speed of the ink and the mechanical strength after curing.

[0017] Preferably, the photoinitiator is 2,4,6-trimethylbenzoyl diphenylphosphine oxide.

[0018] Preferably, the defoamer in the present invention is a polyether silicone copolymer defoamer, including BYK-810, TEGO 920, TEGO 843, TEGO 883 and / or TEGO 825, so as to reduce the surface tension of the raw materials during the production of the ink, thereby achieving the purpose of suppressing the generation of foam.

[0019] Preferably, the dispersant is a high molecular weight polymer solution, including BYK-163, BYK-9077, BYK-9151, BYK-111 and / or TEGO Dispers 670 wetting dispersant, and the concentration of the active component contained is above 40 wt%, which can achieve the effects of reducing the time and energy required for the dispersion process, stabilizing the dispersed copper-nickel-iron alloy electromagnetic absorber, and can also modify the surface properties of the absorber particles and adjust the motility of the copper-nickel-iron alloy electromagnetic absorber particles. It is found through experiments that the effect is better when the content of the active component is above 40 wt%.

[0020] Preferably, the surfactant is a polysiloxane-polyether copolymer surfactant, including TEGOTwin4100, Dow HW 1000, Sangjing Chemical ST-333 and / or Sangjing Chemical COATOSIL 77, which can significantly reduce the surface tension and increase the wettability of the ink to the substrate.

[0021] It should be noted that from the amounts of each raw material, it can be seen that the addition amount of the hyperbranched polyacrylate resin is relatively large. It is both the main material and the main substance that provides the mechanical strength required for the ink, and also plays a role in increasing the curing speed. Therefore, its addition amount is relatively large. If the addition amount is too small, the dispersibility and service performance required by the present invention may not be achieved. The silicone-modified polyurethane acrylate and acryloylmorpholine play a role in enhancing the mechanical strength after curing and are mainly used in combination with the hyperbranched polyacrylate resin. Therefore, the addition amount is relatively small. 2,4,6-Trimethylbenzoyl diphenylphosphine oxide is a free radical polymerization photoinitiator suitable for the ultraviolet light source of 3D printers (DLP, SLA type). The specific addition amounts of these raw materials have been determined through a large amount of creative work by the inventor. Only when controlled within an appropriate range can the prepared ultraviolet light-curable 3D printing copper-nickel-iron alloy electromagnetic absorption ink meet the required service performance. If the addition amount of a certain raw material is too large or too small, it will affect the mechanical properties of the final ink. In addition, although various additives are common raw materials in this field and are also added correspondingly in other 3D printing ink formulations, their amounts have been adjusted accordingly to adapt to the specific raw material system of the present invention. It is necessary to strictly follow the scheme of the present invention to perform the operation of ingredient preparation and not to randomly change the ingredient amounts.

[0022] The ultraviolet light-curable 3D printing copper-nickel-iron alloy electromagnetic absorption ink of the present invention is applicable to ultraviolet light-curable 3D printers (DLP, SLA type). This ink can be used on light-curable 3D printers with a printing accuracy of 10 μm and can print various complex-shaped and high-precision microwave absorbers. The main raw materials in this ink are hyperbranched polyacrylate resin, aliphatic polyurethane acrylate, and acryloylmorpholine. Among them, the hyperbranched polyacrylate resin can provide the high mechanical strength required for the ink, and the aliphatic polyurethane acrylate can provide the high toughness required for the ink. The copper-nickel-iron alloy, as an electromagnetic absorber, is added to the UV light-curable resin to prepare the copper-nickel-iron alloy electromagnetic absorption ink, which has a synergistic electromagnetic wave dissipation effect of magnetic loss and electrical loss, can greatly improve the electromagnetic wave absorption ability of the material, the material has relatively high wear resistance, and its physical and chemical properties are stable and not easily deformed under high-temperature conditions.

[0023] The ultraviolet light-curable 3D printing copper-nickel-iron alloy electromagnetic absorption ink of the present invention is only applicable to ultraviolet light-curable 3D printers (DLP, SLA type) and is not applicable to other types of 3D printers, which has specificity. For example, laser etching type and fused deposition modeling 3D printers are not applicable to the ink of the present invention. When the inventor conducts specific practices, reasonable ingredient preparation is specifically carried out for ultraviolet light-curable 3D printers, and the various properties of its ink are also more suitable for the electromagnetic absorption field. Since the performance index requirements of ultraviolet light-curable 3D printing inks in other industries are different, when preparing the ingredients of the ink, the types and amounts of the formulations definitely need to be adjusted accordingly.

[0024] In addition to providing an electromagnetic absorption ink of copper-nickel-iron alloy for UV-curable 3D printing, the present invention also provides a preparation method for the 3D printing ink, which includes the following steps: mixing all raw materials, first performing mechanical stirring, after mixing evenly, performing grinding and dispersion, and after passing quality inspection and filtering and packaging, the ink is obtained.

[0025] Among them, the copper-nickel-iron alloy mainly plays the role of electromagnetic absorption in the ink. The hyperbranched polyacrylate resin is one of the main components in the ink, which plays the role of dispersing the copper-nickel-iron alloy absorbent and enables the ink to have UV-curing characteristics during printing, forming a polymer matrix with a certain mechanical strength after drying, which plays a protective role for the copper-nickel-iron alloy absorbent. The organosilicon-modified polyurethane acrylate and acryloylmorpholine have a synergistic effect, which can improve the mechanical strength, curing speed and stability of the ink, etc. The dispersant is a surfactant, which can reduce the interfacial tension between liquid / solid, enhance the wettability of the absorbent, improve the mixing and stirring efficiency. The dispersant adsorbs on the surface of the absorbent to form a charge effect or steric hindrance effect, preventing the copper-nickel-iron alloy from flocculating and settling, and keeping the ink in a stable state. Since the ink is extremely easy to generate bubbles during stirring and grinding, which affects the grinding efficiency and effect, an antifoaming agent should be added to the ink system. During 3D printing, it is required that the ink has a good leveling effect to ensure the surface smoothness and precision requirements of the printed structure, so a surfactant needs to be added to reduce the surface tension of the ink system.

[0026] Among them, the rate of mechanical mixing and stirring of all raw materials is controlled between 210 - 480 rpm, and the stirring time is controlled between 22 - 46 min.

[0027] Preferably, a sand mill is used during the grinding process. The working pressure of the diaphragm pump of the sand mill is between 0.23 - 0.49 MPa, and it is ground repeatedly for 2 - 5 times to make the particle size of the ink product more uniform and the flatness better.

[0028] In addition, the ink of the present invention has good printing applicability, and the particle size of grinding is controlled below 8.4 μm, preferably between 3.8 - 8.4 μm.

[0029] The preparation method of the electromagnetic absorption ink of copper-nickel-iron alloy in the embodiment of the present invention has the advantages of being able to completely retain the effective components of the raw materials, and has the advantages of simple method, easy to operate, tight connection between front and back steps, mild operating conditions, etc. The inventor finally adopted a better preparation route through repeated experiments.

[0030] The present invention generates no waste residue during the entire operation process, is green and environmentally friendly, has a relatively simple operation process, and is easy to industrialize. The above preparation method is only one of the relatively superior preparation methods among numerous preparation methods, and does not represent the only preparation method. As long as the preparation method for preparing the ink with the effects of the present invention by using the raw materials of the present invention is within the protection scope of the present invention.

[0031] In addition, the present invention also provides the application of the copper-nickel-iron alloy electromagnetic absorption ink for 3D printing in ultraviolet light-curing 3D printing. This ink can be used in UV light-curing molding DLP-type and SLA-type 3D printers. The DLP 3D printer includes Creality LD-003, and the SLA 3D printer includes Formlabs form3+. The ink of the present invention has good printing quality, strong electromagnetic loss ability, wide electromagnetic absorption frequency band, high mechanical strength, good surface flatness, small volume shrinkage rate, fast curing speed, and high molding accuracy. The ink of the present invention can be printed using a UV light-curing molding (DLP, SLA type) 3D printer to quickly manufacture electromagnetic absorbers with various shapes and high precision.

[0032] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0033] (1) In the formula of the ink of the present invention, a copper-nickel-iron alloy is used as the electromagnetic absorber. The copper-nickel-iron alloy is a special soft magnetic alloy, which has a relatively high magnetic permeability and magnetic hysteresis loss, high corrosion resistance and excellent mechanical properties, good thermal stability, and certain electrical conductivity. The electromagnetic absorption ink prepared using this absorber can play a synergistic electromagnetic wave dissipation effect of magnetic loss and electrical loss, can greatly improve the electromagnetic wave absorption ability of the material, and has a relatively wide absorption frequency band. The cured material has relatively high wear resistance, stable physical and chemical properties and is not easily deformed under high temperature conditions, and can be applied to the rapid manufacture of electromagnetic absorbers with various shapes and high precision in military and civilian fields.

[0034] (2) The ultraviolet light-curing 3D printing copper-nickel-iron alloy electromagnetic absorption ink of the present invention is suitable for printing with a UV light-curing molding (DLP, SLA type) 3D printer. The production process of this ink is simple, has good leveling property, high mechanical strength, good surface flatness, small volume shrinkage rate, fast curing speed, and high molding accuracy after curing. Generally, 3D printing inks of metal alloys are most likely to have problems such as slow curing speed, poor dispersibility, poor stability, and easy sedimentation, and cannot meet the requirements of printing machines. However, the present invention has well solved this technical problem through reasonable combination and ratio of raw materials.

[0035] (3) The preparation method of the ultraviolet-curable 3D printing copper-nickel-iron alloy electromagnetic absorption ink of the present invention has the advantages of being able to completely retain the effective components of the raw materials, and is also simple and easy to operate, with the steps before and after being closely connected, and the operating conditions being mild. The inventor finally adopted the optimal preparation route through repeated experiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a schematic diagram of the 3D printing mechanical property test sample and the electromagnetic parameter test sample;

[0037] Figure 2 It is the coaxial method sample size of the electromagnetic parameter test sample. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0038] The following will describe the implementation scheme of the present invention in detail in conjunction with the embodiments. However, those skilled in the art will understand that the following embodiments are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention. For those not specified in the embodiments, they are carried out according to the conventional conditions or the conditions recommended by the manufacturer. Those reagents or instruments not specified in the manufacturer are all conventional products that can be obtained through commercial purchase.

[0039] The copper-nickel-iron alloy electromagnetic absorption ink applicable to ultraviolet-curable 3D printing of the present invention is mainly prepared from the following raw materials: by mass, 5-13.5 parts of copper-nickel-iron alloy electromagnetic absorber, 37-50.5 parts of hyperbranched polyacrylate resin, 32.5-46.5 parts of organosilicon-modified polyurethane acrylate, 6-13.5 parts of acryloylmorpholine, 2.2-5.3 parts of photoinitiator 2,4,6-trimethylbenzoyl diphenylphosphine oxide, 0.6-2.3 parts of defoamer, 0.6-2.8 parts of dispersant, and 1.5-3.5 parts of surfactant. The preparation method includes: mixing all the raw materials and stirring evenly, grinding and dispersing, and then, after passing the quality inspection and filtering and packaging, the product is obtained.

[0040] The raw materials used in the following embodiments: Copper-nickel-iron alloy electromagnetic absorber: the content of nickel is 38-42 wt.%, the content of copper is 28-32 wt.%, the content of iron is 26-34 wt.%, the powder particle size ≤ 50 microns, Shanghai Alloy Powder Science Research Center; Organosilicon-modified polyurethane acrylate: Shanghai Yinchang YC 5016; Hyperbranched polyacrylate resin: Shanghai Yinchang YC2509S; Photoinitiator: 2,4,6-trimethylbenzoyl diphenylphosphine oxide; Defoamer: TEGO 843; Dispersant: TEGO Dispers670; Surfactant: TEGO Twin4100.

[0041] Example 1

[0042] The preparation method of the copper-nickel-iron alloy electromagnetic absorption ink applicable to ultraviolet-curable 3D printing is as follows:

[0043] 1) Weigh each raw material according to the following quality: 6.5 kg of copper-nickel-iron alloy electromagnetic absorber, 41.6 kg of hyperbranched polyacrylate resin, 36.1 kg of organosilicon-modified polyurethane acrylate, 8.0 kg of acryloylmorpholine, 2.6 kg of photoinitiator 2,4,6-trimethylbenzoyl diphenylphosphine oxide, 1.3 kg of defoamer, 1.8 kg of dispersant, and 2.1 kg of surfactant;

[0044] 2) After weighing the above components, pour them into a stirring device and stir at a speed of 230 rpm for 45 minutes by a mechanical stirrer, then grind and disperse with a sand mill. The working pressure of the diaphragm pump is 0.25 MPa, and grind repeatedly for 3 - 5 times until the particle size is below 8.2 μm. If the particle size does not meet the standard, continue grinding. Finally, detect the various indicators and properties of the ink. After passing the standard, filter and package to obtain the finished product.

[0045] Example 2

[0046] The preparation method of the copper-nickel-iron alloy electromagnetic absorption ink applicable to ultraviolet light-curing 3D printing is as follows:

[0047] 1) Weigh each raw material according to the following quality: 7.8 kg of copper-nickel-iron alloy electromagnetic absorber, 44.5 kg of hyperbranched polyacrylate resin, 34.4 kg of organosilicon-modified polyurethane acrylate, 6.2 kg of acryloylmorpholine, 3.4 kg of photoinitiator 2,4,6-trimethylbenzoyl diphenylphosphine oxide, 0.8 kg of defoamer, 1.2 kg of dispersant, and 1.7 kg of surfactant;

[0048] 2) After weighing the above components, pour them into a stirring device and stir at a speed of 330 rpm for 32 minutes by a mechanical stirrer, then grind and disperse with a sand mill. The working pressure of the diaphragm pump is 0.45 MPa, and grind repeatedly for 2 - 4 times until the particle size is below 7.4 μm. If the particle size does not meet the standard, continue grinding. Finally, detect the various indicators and properties of the ink. After passing the standard, filter and package to obtain the finished product.

[0049] Example 3

[0050] The preparation method of the copper-nickel-iron alloy electromagnetic absorption ink applicable to ultraviolet light-curing 3D printing is as follows:

[0051] 1) Weigh each raw material according to the following quality: 9.4 kg of copper-nickel-iron alloy electromagnetic absorber, 38.6 kg of hyperbranched polyacrylate resin, 33.7 kg of organosilicon-modified polyurethane acrylate, 8.7 kg of acryloylmorpholine, 4.2 kg of photoinitiator 2,4,6-trimethylbenzoyl diphenylphosphine oxide, 1.9 kg of defoamer, 1.3 kg of dispersant, and 2.2 kg of surfactant;

[0052] 2) Weigh the above components and pour them into a stirring device. Stir at a speed of 360 rpm with a mechanical stirrer for 37 minutes, then grind and disperse with a sand mill. The working pressure of the diaphragm pump is 0.45 MPa, and grind repeatedly for 3 - 4 times until the particle size is between 4.9 - 7.7 μm. If the particle size does not meet the standard, continue grinding. Finally, detect the various indicators and properties of the ink. After passing the test, filter and package to obtain the finished product.

[0053] Example 4

[0054] The preparation method of the copper - nickel - iron alloy electromagnetic absorption ink applicable to ultraviolet - light - curing 3D printing is as follows:

[0055] 1) Weigh each raw material according to the following mass: 10.8 kg of copper - nickel - iron alloy electromagnetic absorption agent, 40.8 kg of hyperbranched polyacrylate resin, 36.1 kg of organosilicon - modified polyurethane acrylate, 6.2 kg of acryloylmorpholine, 2.4 kg of photoinitiator 2,4,6 - trimethylbenzoyl diphenylphosphine oxide, 0.9 kg of defoamer, 1.2 kg of dispersant, 1.6 kg of surfactant;

[0056] 2) Weigh the above components and pour them into a stirring device. Stir at a speed of 370 rpm with a mechanical stirrer for 37 minutes, then grind and disperse with a sand mill. The working pressure of the diaphragm pump is 0.48 MPa, and grind repeatedly for 2 - 3 times until the particle size is below 7.5 μm. If the particle size does not meet the standard, continue grinding. Finally, detect the various indicators and properties of the ink. After passing the test, filter and package to obtain the finished product.

[0057] Example 5

[0058] The preparation method of the copper - nickel - iron alloy electromagnetic absorption ink applicable to ultraviolet - light - curing 3D printing is as follows:

[0059] 1) Weigh each raw material according to the following mass: 11.4 kg of copper - nickel - iron alloy electromagnetic absorption agent, 43.6 kg of hyperbranched polyacrylate resin, 32.5 kg of organosilicon - modified polyurethane acrylate, 7.9 kg of acryloylmorpholine, 2.2 kg of photoinitiator 2,4,6 - trimethylbenzoyl diphenylphosphine oxide, 1 kg of defoamer, 0.8 kg of dispersant, 1.6 kg of surfactant;

[0060] 2) Weigh the above components and pour them into a stirring device. Stir at a speed of 420 rpm with a mechanical stirrer for 22 minutes, then grind and disperse with a sand mill. The working pressure of the diaphragm pump is 0.33 MPa, and grind repeatedly for 2 - 4 times until the particle size is between 4.8 - 8.2 μm. If the particle size does not meet the standard, continue grinding. Finally, detect the various indicators and properties of the ink. After passing the test, filter and package to obtain the finished product.

[0061] Example 6

[0062] The preparation method of the copper-nickel-iron alloy electromagnetic absorption ink applicable to ultraviolet light-curing 3D printing is as follows:

[0063] 1) Weigh each raw material according to the following mass: 10.1 kg of copper-nickel-iron alloy electromagnetic absorber, 37.5 kg of hyperbranched polyacrylate resin, 34.8 kg of organosilicon-modified polyurethane acrylate, 10.2 kg of acryloylmorpholine, 2.6 kg of photoinitiator 2,4,6-trimethylbenzoyl diphenylphosphine oxide, 1.4 kg of defoamer, 1.3 kg of dispersant, and 2.1 kg of surfactant;

[0064] 2) Pour the above components into a stirring device after weighing, stir at a speed of 400 rpm with a mechanical stirrer for 23 minutes, then grind and disperse with a sand mill. The working pressure of the diaphragm pump is 0.46 MPa, and grind repeatedly for 3 - 4 times until the particle size is between 4.7 - 7.1 μm. If the particle size does not meet the standard, continue to grind. Finally, detect the various indicators and properties of the ink. After passing the test, filter and package to obtain the finished product.

[0065] Performance test:

[0066] Take the copper-nickel-iron alloy electromagnetic absorption ink applicable to ultraviolet light-curing 3D printing produced in Examples 1 - 6 for printing performance detection. Use an ultraviolet light-curing 3D printer (Creative 3D LD-003 3D printer) to print electromagnetic absorption materials. As Figure 1 shown, they are the samples for 3D printing mechanical property test and the samples for electromagnetic parameter test. Both the 3D printing mechanical property test samples and the electromagnetic parameter test samples include real and imaginary parts, and test the mechanical properties and electromagnetic properties.

[0067] 1. Particle size μm: Refer to GB / T 1724-2019 Detection of grinding fineness of printing inks.

[0068] 2. Young's modulus MPa, tensile fracture length %, tensile stress MPa: Refer to GBT1040.2-2022 Determination of tensile properties of plastics.

[0069] 3. Surface tension mN / m: Test at 25 °C using a surface tension meter.

[0070] 4. Conductivity, permeability, electromagnetic loss (dB): Use a vector network analyzer (VNA, N5234A PAN-L, Agilent, USA) to analyze the electromagnetic parameters of the material, and the test frequency range is 2 - 18 GHz.

[0071] The electromagnetic performance test of the sample is carried out on a vector network analyzer. The coaxial test fixture is connected to the two ports of the vector microwave network analyzer through two coaxial cables. Calibrate the system before measurement, then carefully place the sample in the fixture, and test the electromagnetic parameters through the vector network analyzer.

[0072] For coaxial samples, such as Figure 1 shown in the structural schematic diagram of the sample coaxial sample, as Figure 2 shown in the coaxial method sample size, the size is: inner diameter is 3.04 mm, outer diameter is 7 mm, and thickness is 2 mm.

[0073] The specific process of sample preparation is as follows:

[0074] (1) Calculate and weigh the UV-curable microwave absorbing material to be tested according to the pre-determined ratio;

[0075] (2) Pour the UV-curable microwave absorbing material into the mold;

[0076] (3) Carry out photocuring on the UV-curable microwave absorbing material in the mold;

[0077] (4) After complete curing, use a blade and fine sandpaper to level the surface of the sample to achieve the appropriate size.

[0078] Use the measured electromagnetic parameters to further analyze the electromagnetic wave absorption performance of the composite material, and study the relationship between the loss value RL of the electromagnetic wave reflection absorbed by the single-layer flat plate of the same thickness and the frequency. Based on the electromagnetic parameters, calculate the electromagnetic loss according to the absorption screen theory.

[0079] RL(dB) = 20log|(Z in - 1) / (Z in + 1)| (1)

[0080] Z in = Z0(μ γ / ε γ ) 1 / 2 tanh[j(2πfd / c)(μ γ ε γ ) 1 / 2 (2)

[0081] Among them, Z in and Z0 respectively represent the normalized input impedance of the wave-absorbing material and the input impedance of free space, while μ γ and ε γ respectively represent the relative magnetic permeability and dielectric constant of the material, d is the thickness of the absorption layer, c represents the speed of light, and f represents the free space frequency of the electromagnetic wave. As long as ε is large enough, the larger μ is, the better the absorption of electromagnetic waves. However, ε and μ are not simply the larger the better, and influencing factors such as impedance and specific materials also need to be considered.

[0082] The specific test results are shown in Table 1 below:

[0083] Table 1 Test Results

[0084]

[0085]

[0086] As can be seen from the above table, the ink of the present invention has appropriate viscosity, uniform particle size, strong electromagnetic loss ability, wide electromagnetic absorption frequency band, high mechanical strength, good surface flatness, small volume shrinkage rate, fast curing speed, high forming accuracy, and good printing performance. Such effects are inseparable from the specific raw material formula adopted in the present invention.

[0087] The ultraviolet-curable 3D printing copper-nickel-iron alloy electromagnetic absorption ink of the embodiment of the present invention uses copper-nickel-iron alloy as an electromagnetic absorber, which can play a synergistic electromagnetic wave dissipation effect of magnetic loss and electrical loss, greatly improving the electromagnetic wave absorption ability of the material and having a wide absorption frequency band. The hyperbranched polyacrylate resin, aliphatic polyurethane acrylate and acryloylmorpholine are compounded as the polymer matrix material. After curing, the material has high wear resistance, stable physical and chemical properties and is not easy to deform under high temperature conditions, and can be applied to the rapid manufacturing of electromagnetic absorbers with various shapes and high precision in military and civilian fields.

[0088] Although the present invention has been illustrated and described with reference to specific embodiments, it should be realized that many other changes and modifications can be made without departing from the spirit and scope of the present invention. Therefore, this means that all such changes and modifications that fall within the scope of the present invention are included in the appended claims.

Claims

1. An electromagnetic absorption ink made of a copper-nickel-iron alloy for 3D printing, characterized in that: It is prepared from the following raw materials: by mass parts, 5 - 13.5 parts of copper-nickel-iron alloy electromagnetic absorber, 37 - 50.5 parts of hyperbranched polyacrylate resin, 32.5 - 46.5 parts of organosilicon-modified polyurethane acrylate, 6 - 13.5 parts of acryloylmorpholine, 2.2 - 5.3 parts of photoinitiator, 0.6 - 2.3 parts of defoamer, 0.6 - 2.8 parts of dispersant, and 1.5 - 3.5 parts of surfactant.

2. The electromagnetic absorption ink made of copper-nickel-iron alloy for 3D printing according to claim 1, wherein: In the copper-nickel-iron alloy electromagnetic absorber, by mass percentage, the content of nickel is 38 - 42%, the content of copper is 28 - 32%, and the content of iron is 26 - 34%.

3. The electromagnetic absorption ink made of copper-nickel-iron alloy for 3D printing according to claim 2, characterized in that: The copper-nickel-iron alloy electromagnetic absorber is in powder form, and the powder particle size is ≤ 50 microns.

4. The electromagnetic absorption ink made of copper-nickel-iron alloy for 3D printing according to claim 1, characterized in that: The degree of branching of the hyperbranched polyacrylate resin is 0.5 - 0.9, and the molecular weight is 1500 - 10000; the organosilicon-modified polyurethane acrylate has 3 - 6 functional groups, and the molecular weight is 15000 - 20000.

5. The electromagnetic absorption ink made of copper-nickel-iron alloy for 3D printing according to claim 1, characterized in that: The photoinitiator is 2,4,6-trimethylbenzoyl diphenylphosphine oxide; the defoamer is a polyether silicone copolymer defoamer; the dispersant is TEGO Dispers 670 wetting dispersant; the surfactant is a polysiloxane-polyether copolymer surfactant.

6. The preparation method of the copper-nickel-iron alloy electromagnetic absorption ink for 3D printing according to any one of claims 1 - 5 includes the following steps: Mix all the raw materials, first carry out mechanical stirring, after mixing evenly, carry out grinding and dispersion, and after passing quality inspection, filter and package.

7. The preparation method of the copper-nickel-iron alloy electromagnetic absorption ink for 3D printing according to claim 6, wherein: The rate of the mechanical stirring is between 210 - 480 rpm, and the stirring time is between 22 - 46 min.

8. The preparation method of the copper-nickel-iron alloy electromagnetic absorption ink for 3D printing according to claim 6, characterized in that: Use a sand mill for grinding and dispersion. The working pressure of the diaphragm pump of the sand mill is between 0.23 - 0.49 MPa, and grind repeatedly for 2 - 5 times to make the particle size of the ink finished product more uniform and the flatness better.

9. The preparation method of the copper-nickel-iron alloy electromagnetic absorption ink for 3D printing according to claim 6, characterized in that: The particle size after grinding is below 8.4 μm.

10. The application of the copper-nickel-iron alloy electromagnetic absorption ink for 3D printing according to any one of claims 1 - 5 in ultraviolet light-curing 3D printing.

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