Iron-silicon-aluminum alloy electromagnetic absorption ink for 3D printing and preparation method of iron-silicon-aluminum alloy electromagnetic absorption ink

Abstract

The invention relates to iron-silicon-aluminum alloy electromagnetic absorption ink for 3D printing and a preparation method of the iron-silicon-aluminum alloy electromagnetic absorption ink, and belongs to the field of ink processing. The iron-silicon-aluminum alloy electromagnetic absorption ink is prepared from the following raw materials in parts by mass: 5 to 12 parts of an iron-silicon-aluminum alloy electromagnetic absorbent, 50 to 65 parts of hyperbranched polyacrylate resin, 6 to 15 parts of organic silicon modified polyurethane acrylate, 12 to 18 parts of acryloylmorpholine, 1 to 4 parts of a photoinitiator, 0.5 to 2.5 parts of a defoaming agent, 0.5 to 4.5 parts of a dispersing agent and 1 to 2.5 parts of a surfactant. According to the iron-silicon-aluminum alloy electromagnetic absorption ink suitable for ultraviolet curing 3D printing, the electromagnetic wave absorption capacity of a material is greatly improved, and the iron-silicon-aluminum alloy electromagnetic absorption ink has a 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 in particular, to an iron-silicon-aluminum alloy electromagnetic absorption ink for 3D printing and a preparation method thereof, and particularly to an iron-silicon-aluminum alloy electromagnetic absorption ink suitable 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 pollution source, 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 processability, 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 by initiating the chain polymerization reaction of monomers and prepolymers in the resin through ultraviolet light. Selecting UV light-curing resin as the matrix material, filling with electromagnetic absorption agents to prepare electromagnetic absorption ink, and using UV light-curing 3D printing for printing can quickly design and print various complex-shaped and high-precision electromagnetic absorbers, 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 500μm). The added electromagnetic absorbers 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, easy to break, and 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 an iron-silicon-aluminum 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 an iron-silicon-aluminum 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 iron-silicon-aluminum 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 and 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 of the above-mentioned iron-silicon-aluminum 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 the front and back steps being closely connected and the operating conditions being mild.

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

[0009] An iron-silicon-aluminum alloy electromagnetic absorption ink for 3D printing is mainly prepared from the following raw materials: by mass, 5-12 parts of iron-silicon-aluminum alloy electromagnetic absorber, 50-65 parts of hyperbranched polyacrylate resin, 6-15 parts of organosilicon-modified polyurethane acrylate, 12-18 parts of acryloylmorpholine, 1-4 parts of photoinitiator, 0.5-2.5 parts of defoamer, 0.5-4.5 parts of dispersant, and 1-2.5 parts of surfactant.

[0010] To further optimize the raw material formula, the amounts of raw materials are as follows: 6 - 10 parts of iron-silicon-aluminum alloy electromagnetic absorber, 52 - 59 parts of hyperbranched polyacrylate resin, 6.5 - 12.5 parts of organosilicon-modified polyurethane acrylate, 13.5 - 17.5 parts of acryloylmorpholine, 1.5 - 3 parts of photoinitiator, 1 - 1.8 parts of defoamer, 0.8 - 3 parts of dispersant, and 1.5 - 2.2 parts of surfactant.

[0011] In addition, the amounts of raw materials can also be: 7 - 11 parts of iron-silicon-aluminum alloy electromagnetic absorber, 61 - 63.5 parts of hyperbranched polyacrylate resin, 7 - 13 parts of organosilicon-modified polyurethane acrylate, 14 - 17 parts of acryloylmorpholine, 1.5 - 3 parts of photoinitiator, 0.8 - 2.2 parts of defoamer, 0.6 - 3.5 parts of dispersant, and 1 - 2 parts of surfactant.

[0012] More preferably, the amounts are: 8.5 - 9.2 parts of iron-silicon-aluminum alloy electromagnetic absorber, 61.5 - 62 parts of hyperbranched polyacrylate resin, 9.5 - 12 parts of organosilicon-modified polyurethane acrylate, 15.5 - 16.5 parts of acryloylmorpholine, 1.8 - 2.8 parts of photoinitiator, 1 - 1.5 parts of defoamer, 1.2 - 2.2 parts of dispersant, and 1.5 - 1.8 parts of surfactant.

[0013] Among them, for the iron-silicon-aluminum alloy electromagnetic absorber, by mass percentage, the aluminum content is 9 - 10%, the silicon content is 5 - 6%, and the iron content is 84 - 86%. The iron-silicon-aluminum alloy electromagnetic absorber is in powder form, and the powder particle size ≤ 50 microns. The iron-silicon-aluminum 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. Iron-silicon-aluminum alloy is a special soft magnetic alloy with low hysteresis coefficient, high magnetic induction intensity, good thermal stability, strong corrosion resistance, small edge loss, and certain electrical conductivity. Using iron-silicon-aluminum alloy as an electromagnetic absorber and adding it to UV curable resin to prepare iron-silicon-aluminum alloy electromagnetic absorption ink has a synergistic electromagnetic wave dissipation effect of magnetic loss and electrical loss, which 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, which can meet the grinding performance and printing performance of the ink. Moreover, the ink using hyperbranched polyacrylate resin and organosilicon-modified polyurethane acrylate can be printed on ultraviolet-curable 3D printers (DLP, SLA types), 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. In this way, by reducing the surface tension of the raw materials during the production of the ink, the purpose of suppressing the generation of foam can be achieved.

[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. The concentration of the active component contained is more than 40wt%, which can reduce the time and energy required to complete the dispersion process, stabilize the dispersed iron-silicon-aluminum alloy electromagnetic absorber, and can also modify the surface properties of the absorber particles and adjust the motility of the iron-silicon-aluminum alloy electromagnetic absorber particles. It is found through experiments that the effect is better when the content of the active component is more than 40wt%.

[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 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 were 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 iron-silicon-aluminum alloy electromagnetic absorption ink meet the required 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 for operation and batching, and do not randomly change the batching amounts.

[0022] The electromagnetic absorption ink of iron-silicon-aluminum alloy for ultraviolet light-curable 3D printing of the present invention is applicable to ultraviolet light-curable 3D printers, can be used on light-curable 3D printers, and the printing accuracy is 10 μm. It can print various complex-shaped and high-precision microwave absorbers. The main raw materials in this ink are hyperbranched polyacrylate resin, silicone-modified aliphatic polyurethane acrylate, and acryloylmorpholine. Among them, the hyperbranched polyacrylate resin can provide the high mechanical strength required for the ink, and the silicone-modified aliphatic polyurethane acrylate can provide the high toughness required for the ink. As an electromagnetic absorber, the iron-silicon-aluminum alloy is added to the UV light-curable resin to prepare the iron-silicon-aluminum alloy electromagnetic absorption ink, which has a synergistic electromagnetic wave dissipation effect of magnetic loss and electric 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 iron-silicon-aluminum 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 carried out specific practices, reasonable batching was specifically carried out for ultraviolet light-curable 3D printers, and the performance of its ink is 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 formulating the raw materials 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 iron-silicon aluminum alloy for ultraviolet curing 3D printing, the present invention also provides a preparation method of 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 obtaining the product after passing quality inspection, filtering and packaging.

[0025] Among them, the iron-silicon aluminum alloy mainly plays an electromagnetic absorption role in the ink. The hyperbranched polyacrylate resin is one of the main components in the ink, which plays a role in dispersing the iron-silicon aluminum alloy absorbent and enables the ink to have ultraviolet curing characteristics during printing. After drying, it forms a polymer matrix with certain mechanical strength, which plays a protective role for the iron-silicon aluminum 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 and 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 iron-silicon aluminum 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 efficiency and effect of grinding, 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 250 - 450 rpm, and the stirring time is controlled between 20 - 40 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 0.25 - 0.45 MPa, and it is ground repeatedly for 2 - 5 times to make the particle size of the ink finished 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 4.5 μm, preferably between 1 - 4.5 μm.

[0029] The preparation method of the electromagnetic absorption ink of iron-silicon aluminum 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 produces no waste residue during the whole operation process, is green and environment-friendly, has a relatively simple operation process and is easy to industrialize. The above preparation method is only one of the relatively superior ones among many preparation methods, and does not represent the only preparation method. As long as the preparation method of the ink with the effects of the present invention is prepared by using the raw materials of the present invention, it is within the protection scope of the present invention.

[0031] In addition, the present invention also provides an application of the iron-silicon-aluminum alloy electromagnetic absorption ink for 3D printing in ultraviolet light-curing 3D printing. This ink can be used in UV light-curing DLP-type and SLA-type 3D printers. The DLP 3D printer includes the Creality LD-003, and the SLA 3D printer includes the Formlabs form3+.

[0032] 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 forming precision. The ink of the present invention can be printed by using a UV light-curing (DLP, SLA type) 3D printer to quickly manufacture electromagnetic absorbers with various shapes and high precision.

[0033] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0034] (1) In the formula of the ink of the present invention, iron-silicon-aluminum alloy is used as the electromagnetic absorber. It has a low hysteresis coefficient, high magnetic induction intensity, good thermal stability, strong corrosion resistance, small edge loss and certain electrical conductivity. The electromagnetic absorption ink prepared by 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 wide absorption frequency band. The cured 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 manufacture of electromagnetic absorbers with various shapes and high precision in military and civilian fields.

[0035] (2) The iron-silicon-aluminum alloy electromagnetic absorption ink for ultraviolet light-curing 3D printing of the present invention is suitable for printing by using a UV light-curing (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 forming precision 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.

[0036] (3) The preparation method of the iron-silicon-aluminum alloy electromagnetic absorption ink for UV-curable 3D printing of the present invention has the advantages of being able to completely retain the effective components of the raw materials, and also has the advantages of simple method, easy operation, tight connection of front and back steps, mild operation conditions, etc. The inventor finally adopted the optimal preparation route through repeated experiments. Description of the Drawings

[0037] Figure 1 Schematic diagrams of the 3D printing mechanical property test samples and electromagnetic parameter test samples;

[0038] Figure 2 Coaxial method sample size of the electromagnetic parameter test sample. Detailed Description of the Invention

[0039] The following will describe the implementation scheme of the present invention in detail in combination 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.

[0040] The iron-silicon-aluminum alloy electromagnetic absorption ink applicable to UV-curable 3D printing of the present invention is mainly prepared from the following raw materials: by mass, 5-12 parts of iron-silicon-aluminum alloy electromagnetic absorption agent, 50-65 parts of hyperbranched polyacrylate resin, 6-15 parts of organosilicon-modified polyurethane acrylate, 12-18 parts of acryloylmorpholine, 1-4 parts of photoinitiator 2,4,6-trimethylbenzoyl diphenylphosphine oxide, 0.5-2.5 parts of defoamer, 0.5-4.5 parts of dispersant, and 1-2.5 parts of surfactant. The preparation method includes: mixing all the raw materials evenly, grinding and dispersing, and then, after passing the quality inspection and filtering and packaging, the product is obtained.

[0041] The raw materials used in the following embodiments: Iron-silicon-aluminum alloy electromagnetic absorption agent: the content of aluminum is 9-10 wt.%, the content of silicon is 5-6 wt.%, the content of iron is 84-86 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.

[0042] Example 1

[0043] The preparation method of the iron-silicon-aluminum alloy electromagnetic absorption ink applicable to UV-curable 3D printing is as follows:

[0044] 1) Weigh each raw material according to the following masses: 5.5 kg of iron-silicon-aluminum alloy electromagnetic absorber, 58.6 kg of hyperbranched polyacrylate resin, 8.8 kg of organosilicon-modified polyurethane acrylate, 17.4 kg of acryloylmorpholine, 3.5 kg of photoinitiator 2,4,6-trimethylbenzoyl diphenylphosphine oxide, 1.2 kg of defoamer, 2.5 kg of dispersant, and 2.5 kg of surfactant;

[0045] 2) After weighing the above components, pour them into a stirring device and stir at a speed of 350 rpm for 25 minutes with a mechanical stirrer. Then, grind and disperse with a sand mill. The working pressure of the diaphragm pump is 0.4 MPa, and grind repeatedly for 2 - 4 times until the particle size is below 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.

[0046] Example 2

[0047] The preparation method of an iron-silicon-aluminum alloy electromagnetic absorption ink applicable to UV-curable 3D printing is as follows:

[0048] 1) Weigh each raw material according to the following masses: 9.8 kg of iron-silicon-aluminum alloy electromagnetic absorber, 57.5 kg of hyperbranched polyacrylate resin, 8.7 kg of organosilicon-modified polyurethane acrylate, 13.2 kg of acryloylmorpholine, 3 kg of photoinitiator 2,4,6-trimethylbenzoyl diphenylphosphine oxide, 2.4 kg of defoamer, 3.8 kg of dispersant, and 1.6 kg of surfactant;

[0049] 2) After weighing the above components, pour them into a stirring device and stir at a speed of 270 rpm for 40 minutes with a mechanical stirrer. Then, grind and disperse with a sand mill. The working pressure of the diaphragm pump is 0.42 MPa, and grind repeatedly for 2 - 4 times until the particle size is below 3.5 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 standard, filter and package to obtain the finished product.

[0050] Example 3

[0051] The preparation method of an iron-silicon-aluminum alloy electromagnetic absorption ink applicable to UV-curable 3D printing is as follows:

[0052] 1) Weigh each raw material according to the following masses: 8.2 kg of iron-silicon-aluminum alloy electromagnetic absorber, 61 kg of hyperbranched polyacrylate resin, 12.4 kg of organosilicon-modified polyurethane acrylate, 12.7 kg of acryloylmorpholine, 2.2 kg of photoinitiator 2,4,6-trimethylbenzoyl diphenylphosphine oxide, 0.7 kg of defoamer, 1.8 kg of dispersant, and 1 kg of surfactant;

[0053] 2) Weigh the above components and pour them into a stirring device. Stir at a speed of 360 rpm with a mechanical stirrer for 35 minutes, then grind and disperse with a sand mill. The working pressure of the diaphragm pump is 0.34 MPa, and grind repeatedly for 3 - 4 times until the particle size is between 1 - 2.5 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 standard, filter and package to obtain the finished product.

[0054] Example 4

[0055] The preparation method of iron - silicon - aluminum alloy electromagnetic absorption ink applicable to ultraviolet - curable 3D printing is as follows:

[0056] 1) Weigh each raw material according to the following mass: 11.5 kg of iron - silicon - aluminum alloy electromagnetic absorption agent, 54 kg of hyperbranched polyacrylate resin, 10.6 kg of organosilicon - modified polyurethane acrylate, 13.3 kg of acryloylmorpholine, 3.7 kg of photo - initiator 2,4,6 - trimethylbenzoyl diphenylphosphine oxide, 1.5 kg of defoamer, 2.2 kg of dispersant, 1.1 kg of surfactant;

[0057] 2) Weigh the above components and pour them into a stirring device. Stir at a speed of 370 rpm with a mechanical stirrer for 28 minutes, then grind and disperse with a sand mill. The working pressure of the diaphragm pump is 0.27 MPa, and grind repeatedly for 2 - 3 times until the particle size is below 3 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.

[0058] Example 5

[0059] The preparation method of iron - silicon - aluminum alloy electromagnetic absorption ink applicable to ultraviolet - curable 3D printing is as follows:

[0060] 1) Weigh each raw material according to the following mass: 9.4 kg of iron - silicon - aluminum alloy electromagnetic absorption agent, 58.5 kg of hyperbranched polyacrylate resin, 7.4 kg of organosilicon - modified polyurethane acrylate, 13.7 kg of acryloylmorpholine, 2.7 kg of photo - initiator 2,4,6 - trimethylbenzoyl diphenylphosphine oxide, 2.2 kg of defoamer, 3.6 kg of dispersant, 2.5 kg of surfactant;

[0061] 2) Weigh the above components and pour them into a stirring device. Stir at a speed of 300 rpm with a mechanical stirrer for 32 minutes, then grind and disperse with a sand mill. The working pressure of the diaphragm pump is 0.4 MPa, and grind repeatedly for 2 - 4 times until the particle size is between 1.8 - 3.2 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.

[0062] Example 6

[0063] The preparation method of the iron-silicon-aluminum alloy electromagnetic absorption ink applicable to ultraviolet curing 3D printing is as follows:

[0064] 1) Weigh each raw material according to the following mass: 6.2 kg of iron-silicon-aluminum alloy electromagnetic absorber, 59.8 kg of hyperbranched polyacrylate resin, 11.9 kg of organosilicon-modified polyurethane acrylate, 16.5 kg of acryloylmorpholine, 2.5 kg of photoinitiator 2,4,6-trimethylbenzoyl diphenylphosphine oxide, 0.8 kg of defoamer, 1.1 kg of dispersant, and 1.2 kg of surfactant;

[0065] 2) Pour the above components into a stirring device after weighing, stir at a speed of 410 rpm with a mechanical stirrer for 23 minutes, then grind and disperse with a sand mill. The working pressure of the diaphragm pump is 0.44 MPa, and grind repeatedly for 3 - 4 times until the particle size is between 2.5 - 3.4 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 test, filter and package to obtain the finished product.

[0066] Performance test:

[0067] Take the iron-silicon-aluminum alloy electromagnetic absorption ink applicable to ultraviolet curing 3D printing produced in Examples 1 - 6 for printing performance detection. Use an ultraviolet curing 3D printer (Creative Dimension LD-003 3D printer) to print electromagnetic absorption materials. As Figure 1 shown, they are samples for 3D printing mechanical property test and samples for electromagnetic parameter test. Both the samples for 3D printing mechanical property test and samples for electromagnetic parameter test include real part and imaginary part, and test mechanical properties and electromagnetic properties.

[0068] 1. Particle size μm: Refer to GB / T 1724-2019 Detection of grinding fineness of printing ink.

[0069] 2. Young's modulus MPa, tensile fracture length %, tensile stress MPa: Refer to GBT1040.2-2022 Determination of tensile properties of plastics.

[0070] 3. Surface tension mN / m: At 25 °C, test with a surface tensiometer.

[0071] 4. Conductivity, magnetic permeability, electromagnetic loss (dB): Use a vector network analyzer (VNA, N5234APAN-L, Agilent, USA) to analyze the electromagnetic parameters of the material, and the test frequency range is 2 - 18 GHz.

[0072] 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.

[0073] For coaxial samples, such as Figure 1 shown in the schematic diagram of the structure of the specimen 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.

[0074] The specific process of sample preparation is as follows:

[0075] (1) Calculate and weigh the UV-curable microwave absorbing material to be tested according to the pre-determined ratio;

[0076] (2) Pour the UV-curable microwave absorbing material into the mold;

[0077] (3) Perform photocuring on the UV-curable microwave absorbing material in the mold;

[0078] (4) After complete curing, use a blade and fine sandpaper to level the surface of the sample to achieve the appropriate size.

[0079] 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.

[0080] RL(dB) = 20log|(Z in -1) / (Z in +1)| (1)

[0081] Z in = Z0(μ γ / ε γ ) 1 / 2 tanh[j(2πfd / c)(μ γ ε γ ) 1 / 2 (2)

[0082] 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 other influencing factors such as impedance and specific materials also need to be considered.

[0083] The specific test results are shown in Table 1 below:

[0084] Table 1 Test Results

[0085]

[0086]

[0087] 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, low volume shrinkage rate, fast curing speed, high forming accuracy, and good printing performance. Such effects are inseparable from the specific raw material formula adopted by the present invention.

[0088] The electromagnetic absorption ink for ultraviolet curable 3D printing in the embodiment of the present invention uses iron-silicon-aluminum 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.

[0089] 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 iron-silicon-aluminum alloy for 3D printing, characterized in that: It is prepared from the following raw materials: by mass parts, 5-12 parts of iron-silicon-aluminum alloy electromagnetic absorber, 50-65 parts of hyperbranched polyacrylate resin, 6-15 parts of organosilicon-modified polyurethane acrylate, 12-18 parts of acryloylmorpholine, 1-4 parts of photoinitiator, 0.5-2.5 parts of defoamer, 0.5-4.5 parts of dispersant, and 1-2.5 parts of surfactant.

2. The electromagnetic absorption ink made of iron-silicon-aluminum alloy for 3D printing according to claim 1, wherein: For the iron-silicon-aluminum alloy electromagnetic absorber described above, by mass percentage, the aluminum content is 9-10%, the silicon content is 5-6%, and the iron content is 84-86%.

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

4. The electromagnetic absorption ink made of iron-silicon-aluminum 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 iron-silicon-aluminum 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 iron-silicon-aluminum 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 iron-silicon-aluminum alloy electromagnetic absorption ink for 3D printing according to claim 6, characterized in that: The rate of the mechanical stirring is between 250-450 rpm, and the stirring time is between 20-40 min.

8. The preparation method of the iron-silicon-aluminum 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 0.25-0.45 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 iron-silicon-aluminum alloy electromagnetic absorption ink for 3D printing according to claim 6, characterized in that: The particle size after grinding is below 4.5 μm.

10. The application of the iron-silicon-aluminum 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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