A wave-absorbing film material with electrostatic adsorption function and a preparation method thereof

Abstract

The application provides a wave-absorbing film material with electrostatic adsorption function and a preparation method thereof, and belongs to the field of functional film materials.The wave-absorbing film material with electrostatic adsorption function comprises a PVC film and PP films compounded on both sides of the PVC film; the preparation raw materials of the PVC film comprise an electromagnetic wave absorber, PVC resin particles and an additive; the electromagnetic wave absorber comprises a carbon material type electromagnetic wave absorber; the additive comprises a stabilizer and a plasticizer; the preparation raw materials of the PP film comprise PP resin particles, a filler and an additive; and the additive comprises a toughening agent and a lubricant.The PVC film and the PP film with wave-absorbing function are compounded by a co-extrusion technology, and then the compounded film is subjected to corona treatment to obtain the wave-absorbing film material with electrostatic adsorption function, which has good insulation, excellent electrostatic adsorption capacity, high surface energy and excellent wave-absorbing performance, and can meet the requirements of different use environments.

Description

Technical Field

[0001] This invention relates to the field of functional thin film materials technology, specifically to a microwave absorbing film material with electrostatic adsorption function and its preparation method. Background Technology

[0002] In the civilian sector, the rapid development of technologies such as electrification has led to increasingly severe electromagnetic pollution in production and daily life. This not only causes interference between devices but also causes irreversible damage to human health. In the military field, advancements in radar, infrared, and other detection methods have made the reality that weapons and equipment are "destroyed if detected" increasingly clear. Improving the battlefield survivability of weapons and equipment has become a key focus for all countries. Against this backdrop, radar-absorbing materials and stealth technology have become crucial for overcoming these problems.

[0003] Compared to stealth through shape and structure, absorbing electromagnetic waves by applying absorbing coatings or attaching absorbing patches is simpler, more feasible, and easier to implement, unaffected by external environmental constraints. Currently, the development of absorbing materials for both civilian and military applications involves several steps. First, the required absorbing performance of the material must be calculated based on the application environment. Second, iterative calculations using electromagnetic simulation software, based on extensive data, determine the electromagnetic parameters required by the absorber to achieve that absorption performance. Finally, samples are prepared using a suitable absorber at appropriate concentrations, and tests are conducted according to standards, with simulation results corrected based on measured values. For military applications, this process requires further investigation. The material must be applied to scaled-down or full-scale models of weaponry to test the actual absorption or stealth effects. This is because the shape and structure of weaponry inherently possess a degree of stealth; the addition of absorbing materials can non-linearly alter its stealth performance.

[0004] After applying radar-absorbing materials to scaled-down or full-scale models, performance deviations often necessitate material optimization followed by re-application and testing, or the model may be repurposed. This requires removing the coated or pasted material through methods such as scraping, heating, tearing, and grinding. These methods consume significant manpower and resources, especially for large stealth aircraft and ships, where the workload is unimaginable. Furthermore, stealth treatment is required for land-based and underwater equipment during transport and movement before reaching the battlefield. Commonly used methods like camouflage netting only achieve optical camouflage and cannot achieve radar imperceptibility, thus having certain drawbacks. Similar issues exist in the civilian sector. For example, the outer surface of large medical equipment needs electromagnetic wave absorption or shielding to prevent interference between devices or harm to the human body. Applying a thick radar-absorbing coating would significantly impair heat dissipation and reduce its lifespan.

[0005] Therefore, how to more conveniently apply microwave absorbing materials in the above situations is an urgent problem to be solved. Summary of the Invention

[0006] In view of the technical problems existing in the background art, the present invention provides a microwave absorbing film material with electrostatic adsorption function and a method for preparing the same, aiming to solve the technical problem of providing a film material that simultaneously possesses microwave absorption and electrostatic adsorption functions.

[0007] In a first aspect, the present invention provides a microwave absorbing film material with electrostatic adsorption function, comprising a PVC film and a PP film laminated on both sides of the PVC film.

[0008] The raw materials for preparing PVC film include electromagnetic wave absorbers, PVC resin granules, and additives; the electromagnetic wave absorbers include carbon-based electromagnetic wave absorbers.

[0009] The raw materials for preparing PP film include PP resin granules, fillers, and additives;

[0010] The additives in the PVC film include stabilizers and plasticizers, and the plasticizers include one or two of fatty acid ester plasticizers and phthalate plasticizers.

[0011] The additives in the PP film include toughening agents and lubricants.

[0012] In this invention, a PVC film with wave-absorbing function is combined with an electrostatic adsorption method. The PVC film with wave-absorbing function is used as the middle layer, and the PP film with high surface resistance is used as the two side layers to prepare a wave-absorbing film material with electrostatic adsorption function. It has good insulation, excellent electrostatic adsorption capacity and high surface energy, and can achieve electrostatic adsorption on the surface of most substrates, so as to adapt to the requirements of different use environments.

[0013] Electrostatic adsorption membrane materials are those that adhere to the substrate surface without adhesive, relying on their own electrostatic adsorption to provide certain functions and protection. They can be reused multiple times, exhibiting particularly strong adhesion to smooth surfaces such as glass, metal, and acrylic. Adding plasticizers can adjust the surface resistance of the membrane before corona treatment. Surface resistance affects the charge accumulation on the membrane surface after corona treatment, thus influencing its electrostatic adsorption capacity.

[0014] Preferably, by weight, the raw materials for preparing the PVC film include: 15-30 parts of electromagnetic wave absorber, 65-80 parts of PVC resin granules, and 4-10 parts of additives; and by weight, the raw materials for preparing the PP film include: 70-85 parts of PP resin granules, 10-25 parts of filler, and 4-10 parts of additives.

[0015] Preferably, the carbon-based electromagnetic wave absorber includes one or more of modified carbon nanotubes, graphene, carbon black, and silicon carbide. By adjusting the type of electromagnetic wave absorber, the wave absorption performance of the membrane material can be rapidly optimized and adjusted.

[0016] Preferably, the molecular weight of the PVC resin granules is 50,000 to 120,000; and the molecular weight of the PP resin granules is 80,000 to 150,000.

[0017] Preferably, the stabilizer in the PVC film preparation raw materials includes one or more of lead salt stabilizers, metal soap stabilizers, organotin stabilizers, organoantimony stabilizers, and organoraven earth stabilizers; including but not limited to the zinc stearate metal soap stabilizer listed in the embodiments of the present invention. Those skilled in the art can also replace it with other conventional lead salt stabilizers, metal soap stabilizers, organotin stabilizers, organoantimony stabilizers, and organoraven earth stabilizers in the field of polymer membrane materials according to actual conditions and needs.

[0018] In this invention, the filler in the raw materials for preparing the PP film can be a conventional filler in the art, such as one or more combinations of talc and silica, used to reinforce the PP film and reduce material costs.

[0019] In this invention, the toughening agent in the raw materials for preparing the PP film can be a conventional toughening agent in the art, such as one or a combination of POE (polyolefin elastomer), EPDM (ethylene-propylene-diolefin terpolymer) and EPR (ethylene-propylene binary copolymer).

[0020] In this invention, the lubricant in the raw materials for preparing the PP film can be a conventional lubricant in the art, such as one or more combinations of oxidized polyethylene wax and polyethylene wax.

[0021] Preferably, the thickness ratio of the PVC film to the single-layer PP film is (20~60):1; the total thickness of the microwave absorbing membrane material with electrostatic adsorption function is ≤600μm, and the thickness of the single-layer PP film is ≤25μm. By adjusting the thickness of the middle PVC film and the two side PP films, the microwave absorption performance of the membrane material can be rapidly optimized and adjusted.

[0022] Secondly, the present invention provides a method for preparing a microwave absorbing film material with electrostatic adsorption function, comprising the following steps:

[0023] S1. Ingredients: Mix electromagnetic wave absorber, PVC resin granules and additives to obtain PVC film initial material; mix PP resin granules, fillers and additives to obtain PP film initial material.

[0024] S2. Co-extrusion: The PVC film initial material and the PP film initial material are co-extruded. The extrusion temperature of the PVC film initial material is controlled at 110℃~120℃ and the extrusion temperature of the PP film initial material is controlled at 160℃~170℃. The co-extruded molten material is extruded and stretched to obtain a PVC film and a PP film laminated on both sides of the PVC film to form an initial composite film.

[0025] S3. Single-sided corona treatment: The initial composite film is subjected to single-sided corona treatment to obtain a microwave absorbing film material with electrostatic adsorption function.

[0026] In this invention, a PVC film with microwave absorption function is used as the middle layer, and a PP film with high surface resistance is used as the two outer layers. A three-layer composite film is prepared by co-extrusion using three extruders. Then, corona treatment is employed. By adjusting appropriate corona treatment processes, such as voltage, frequency, and number of electrodes, a microwave absorption film material with electrostatic adsorption function is obtained. The microwave absorption performance of the composite film can be adjusted and optimized by changing the thickness of the PVC film, the type and amount of absorbent, etc. Single-sided corona treatment allows a certain amount of charge to accumulate on the outermost layer of the composite film, imparting electrostatic force to it.

[0027] Preferably, the co-extrusion in step S2 is performed using an extruder, wherein one extruder is used for the middle PVC film and one extruder is used for each of the two side PP films, for a total of three extruders.

[0028] Preferably, the voltage applied during the corona treatment in step S3 is 10000V / m. 2 ~15000V / m 2 The frequency is 15~25kHz, and the electrode gap is ≤3mm.

[0029] Preferably, the corona treatment in step S3 uses a single-head or multi-head electrode; more preferably, the corona treatment in step S4 uses a 6-head electrode.

[0030] This invention allows for the adjustment of the surface energy of the film after corona treatment by changing the corona treatment process, such as the corona treatment voltage, frequency, and number of electrodes, in order to achieve electrostatic adsorption on different substrates.

[0031] The main mechanism of this invention is as follows: introducing an electromagnetic wave absorber into the PVC film to give it wave absorption function; by changing the thickness of the PVC film, the type and amount of absorber, etc., the wave absorption performance of the composite film can be adjusted and optimized; introducing plasticizers, toughening agents, etc. into the PVC film and PP film to give them high surface resistance values ​​can improve the electrostatic adsorption capacity after corona treatment; preparing a three-layer composite film (PVC film as the middle layer and PP film as the two side layers) by co-extrusion, and then using corona technology, by adjusting the appropriate corona process, such as voltage, frequency, number of electrodes, etc., the resulting composite film material has both wave absorption function and electrostatic adsorption function.

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

[0033] (1) The present invention provides a microwave absorbing membrane material with electrostatic adsorption function, comprising a PVC membrane and PP membranes laminated on both sides of the PVC membrane to form a three-layer sandwich structure, wherein the middle layer is a PVC membrane with microwave absorbing function, and the two side layers are ordinary PP membranes. The three are laminated by co-extrusion technology, and the composite membrane is then subjected to corona treatment to obtain the microwave absorbing membrane material with electrostatic adsorption function. This membrane material has both excellent microwave absorption performance and electrostatic adsorption ability on substrates, and can achieve electrostatic adsorption on the surface of most substrates.

[0034] (2) The preparation process of this invention is simple. By adjusting the thickness of the intermediate PVC film and the type and amount of absorbent, the wave absorption performance of the film material can be quickly optimized and adjusted. By adjusting the corona treatment process, such as the corona treatment voltage, frequency, and number of electrodes of the corona treatment machine, the adsorption force of the film can be changed, thereby adapting to the requirements of different substrate types and usage environments.

[0035] (3) The electrostatic adsorption membrane material provided by the present invention has broad application prospects. It can be easily and quickly attached to the surface of weapons and equipment. When the weapons and equipment are transported to the designated location, the electrostatic adsorption membrane can also be easily removed. It can replace spraying absorbing coatings, pasting absorbing patches and other methods to quickly and seamlessly carry out performance testing and verification of absorbing materials on scaled or reduced models of weapons and equipment. It can be applied to the adsorption of the outer surface of large medical equipment, reducing the interference between electromagnetic waves of different equipment and the harm to the human body, and avoiding the disadvantages of poor heat dissipation caused by materials such as absorbing coatings and absorbing patches. Attached Figure Description

[0036] Figure 1 This is a front view of the microwave absorbing film material with electrostatic adsorption function in Embodiment 1 of the present invention. Detailed Implementation

[0037] The embodiments of the technical solution of the present invention will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative of the technical solution of the present invention and are therefore intended to limit the scope of protection of the present invention.

[0038] Experimental methods not specified in the examples are generally performed under conventional conditions and as described in the manual, or as recommended by the manufacturer. Unless otherwise specified, the general equipment, materials, reagents, etc. used are commercially available.

[0039] Example 1

[0040] A microwave absorbing membrane material with electrostatic adsorption function includes a PVC membrane and PP membranes laminated on both sides of the PVC membrane. The membrane material has a three-layer sandwich structure, wherein the middle layer is a PVC membrane with microwave absorbing function, and the two outer layers are ordinary PP membranes.

[0041] The intermediate PVC film with wave-absorbing function comprises the following raw materials in parts by weight: electromagnetic wave absorber: 25 parts, PVC resin granules: 70 parts, and additives: 5 parts; wherein the electromagnetic wave absorber is graphene; the resin granules are PVC granules with a molecular weight of 80,000 to 100,000; and the additives are zinc stearate (metal soap stabilizer) and dioctyl phthalate (DOP) (phthalate plasticizer), in a ratio of 2:3.

[0042] Each layer of PP film comprises the following raw materials in parts by weight: 75 parts PP resin granules, 20 parts filler, and 5 parts additives; wherein, the PP resin granules are PP granules with a molecular weight of 100,000 to 120,000; the filler is talc; and the additives are POE (polyolefin elastomer) (toughening agent) and oxidized polyethylene wax (lubricant), in a ratio of 2:3.

[0043] The method for preparing the microwave absorbing film material with electrostatic adsorption function includes the following steps:

[0044] 1) Ingredients: Prepare and mix the raw materials for PVC film and PP film according to the designed ratio;

[0045] 2) Raw material loading: Add the evenly mixed raw materials into the feed inlets of their respective extruders. One extruder is used for the middle layer PVC film, and one extruder is used for each of the two side layers PP film, for a total of 3 extruders.

[0046] 3) Extrusion: Adjust the temperature of each zone of the middle layer PVC extruder to 115±5℃, and the temperature of each zone of the two side layer PP extruders to 165±5℃. The molten resin co-extruded passes through the metering pump and filter, and finally enters the die head for extrusion stretching molding.

[0047] 4) Single-sided corona treatment: The prepared three-layer film was subjected to single-sided corona treatment using a corona treatment machine, with an applied voltage of 15000V / m. 2 The frequency is 25kHz, the electrode gap does not exceed 3mm, and a 6-head electrode is used;

[0048] 5) Rolling and cutting: The final prepared microwave absorbing film material with electrostatic adsorption function is rolled into a film.

[0049] In this embodiment, the prepared microwave absorbing membrane with electrostatic adsorption function is a three-layer membrane structure. The thickness of the middle PVC membrane is 550 μm, and the thickness of the two outer PP membranes is 25 μm each. Its front view is shown below. Figure 1 As shown.

[0050] Example 2

[0051] A microwave absorbing membrane material with electrostatic adsorption function includes a PVC membrane and PP membranes laminated on both sides of the PVC membrane. The membrane material has a three-layer sandwich structure, wherein the middle layer is a PVC membrane with microwave absorbing function, and the two outer layers are ordinary PP membranes.

[0052] The intermediate PVC film with wave-absorbing function comprises the following raw materials in parts by weight: electromagnetic wave absorber: 15 parts, PVC resin granules: 65 parts, and additives: 4 parts; wherein the electromagnetic wave absorber is carbon nanotubes; the resin granules are a mixture of PVC granules with molecular weights of 50,000 to 70,000 and 100,000 to 120,000, in a ratio of 1:1; the additives are lead trisulfate (lead salt stabilizer) and di(2-ethylhexyl) azelaic acid ester (DOZ) (fatty acid ester plasticizer), in a ratio of 2:3.

[0053] Each layer of PP film comprises the following raw materials in parts by weight: 70 parts PP resin granules, 10 parts filler, and 4 parts additives; wherein, the PP resin granules are a mixture of PP granules with a molecular weight of 80,000 to 100,000 and 130,000 to 150,000, in a ratio of 1:1; the filler is silica; and the additives are POE (polyolefin elastomer) (toughening agent) and polyethylene wax (lubricant), in a ratio of 2:3.

[0054] The method for preparing the microwave absorbing film material with electrostatic adsorption function includes the following steps:

[0055] 1) Ingredients: Prepare and mix the raw materials for PVC film and PP film according to the designed ratio;

[0056] 2) Raw material loading: Add the evenly mixed raw materials into the feed inlets of their respective extruders. One extruder is used for the middle layer PVC film, and one extruder is used for each of the two side layers PP film, for a total of 3 extruders.

[0057] 3) Extrusion: Adjust the temperature of each zone of the middle layer PVC extruder to 115±5℃, and the temperature of each zone of the two side layer PP extruders to 165±5℃. The molten resin co-extruded passes through the metering pump and filter, and finally enters the die head for extrusion stretching molding.

[0058] 4) Single-sided corona treatment: The prepared three-layer film was subjected to single-sided corona treatment using a corona treatment machine, with an applied voltage of 15000V / m. 2 The frequency is 25kHz, the electrode gap does not exceed 3mm, and a 6-head electrode is used;

[0059] 5) Rolling and cutting: The final prepared microwave absorbing film material with electrostatic adsorption function is rolled into a film.

[0060] In this embodiment, the microwave absorbing membrane with electrostatic adsorption function is a three-layer membrane structure, with the middle PVC membrane having a thickness of 550 μm and the two outer PP membranes each having a thickness of 25 μm.

[0061] Example 3

[0062] A microwave absorbing membrane material with electrostatic adsorption function includes a PVC membrane and PP membranes laminated on both sides of the PVC membrane. The membrane material has a three-layer sandwich structure, wherein the middle layer is a PVC membrane with microwave absorbing function, and the two outer layers are ordinary PP membranes.

[0063] The intermediate PVC film with wave-absorbing function comprises the following raw materials in parts by weight: electromagnetic wave absorber: 30 parts, PVC resin granules: 80 parts, and additives: 10 parts; wherein the electromagnetic wave absorber is graphene; the resin granules are PVC granules with a molecular weight of 100,000 to 120,000; the additives are zinc stearate (metal soap stabilizer), dioctyl phthalate (DOP) (phthalate plasticizer) and di(2-ethylhexyl) azelate (DOZ) (fatty acid ester plasticizer), in a ratio of 2:2:1.

[0064] Each layer of PP film comprises the following raw materials in parts by weight: 85 parts PP resin granules, 25 parts filler, and 10 parts additives; wherein, the PP resin granules are PP granules with a molecular weight of 100,000 to 120,000; the filler is talc; and the additives are POE (polyolefin elastomer) (toughening agent) and oxidized polyethylene wax (lubricant), in a ratio of 2:3.

[0065] The method for preparing the microwave absorbing film material with electrostatic adsorption function includes the following steps:

[0066] 1) Ingredients: Prepare and mix the raw materials for PVC film and PP film according to the designed ratio;

[0067] 2) Raw material loading: Add the evenly mixed raw materials into the feed inlets of their respective extruders. One extruder is used for the middle layer PVC film, and one extruder is used for each of the two side layers PP film, for a total of 3 extruders.

[0068] 3) Extrusion: Adjust the temperature of each zone of the middle layer PVC extruder to 115±5℃, and the temperature of each zone of the two side layer PP extruders to 165±5℃. The molten resin co-extruded passes through the metering pump and filter, and finally enters the die head for extrusion stretching molding.

[0069] 4) Single-sided corona treatment: The prepared three-layer film was subjected to single-sided corona treatment using a corona treatment machine, with an applied voltage of 15000V / m. 2 The frequency is 25kHz, the electrode gap does not exceed 3mm, and a 6-head electrode is used;

[0070] 5) Rolling and cutting: The final prepared microwave absorbing film material with electrostatic adsorption function is rolled into a film.

[0071] In this embodiment, the microwave absorbing membrane with electrostatic adsorption function is a three-layer membrane structure, with the middle PVC membrane having a thickness of 550 μm and the two outer PP membranes each having a thickness of 25 μm.

[0072] Comparative Example 1

[0073] The only difference from Example 1 is that the PVC film raw material does not contain plasticizers; all other steps and conditions are the same as in Example 1. In this comparative example, the thickness of the middle PVC film is 550 μm, and the thickness of both side PP films is 25 μm.

[0074] Comparative Example 2

[0075] The only difference from Example 1 is that the PVC film, by weight, comprises the following raw materials: 5 parts electromagnetic wave absorber, 95 parts PVC resin granules, and 5 parts additives; the PP film, by weight, comprises the following raw materials: 85 parts PP resin granules, 15 parts filler, and 15 parts additives. All other steps and conditions are the same as in Example 1. In this comparative example, the thickness of the middle PVC film is 550 μm, and the thickness of both side PP films is 25 μm.

[0076] Comparative Example 3

[0077] The only difference from Example 1 is that the electromagnetic wave absorber in this example is carbonyl iron powder; the other steps and conditions are the same as in Example 1. The thickness of the middle PVC film is 550 μm, and the thickness of both side PP films is 25 μm.

[0078] Example 4

[0079] The only difference from Example 1 is the single-sided corona treatment in this example: the prepared three-layer film is subjected to single-sided corona treatment using a corona treatment machine, with an applied voltage of 12000V / m. 2 The frequency is 15kHz, the electrode gap is no more than 3mm, and a 6-head electrode is used; other steps and conditions are the same as in Example 1.

[0080] In this embodiment, the thickness of the middle PVC film is 550 μm, and the thickness of the two side PP films is 25 μm.

[0081] Example 5

[0082] The only difference from Example 1 is the single-sided corona treatment in this example: the prepared three-layer film is subjected to single-sided corona treatment using a corona treatment machine, with an applied voltage of 15000V / m. 2 The frequency is 25kHz, the electrode gap is no more than 3mm, and a single electrode is used; other steps and conditions are the same as in Example 1.

[0083] In this embodiment, the thickness of the middle PVC film is 550 μm, and the thickness of the two side PP films is 25 μm.

[0084] Comparative Example 4

[0085] The only difference from Example 1 is the single-sided corona treatment: the prepared three-layer film is subjected to single-sided corona treatment using a corona treatment machine, with an applied voltage of 18000V / m. 2 The frequency is 30kHz, the electrode gap is no more than 3mm, and a 6-head electrode is used; other steps and conditions are the same as in Example 1.

[0086] In this embodiment, the thickness of the middle PVC film is 550 μm, and the thickness of the two side PP films is 25 μm.

[0087] Example 6

[0088] The only difference from Example 1 is that the thickness of the intermediate PVC film in this example is 580 μm, and the thickness of the two side PP films is 10 μm.

[0089] Comparative Example 5

[0090] The only difference from Example 1 is that the thickness of the middle PVC film is 500 μm, and the thickness of the two side PP films is 50 μm.

[0091] Test case

[0092] The electromagnetic absorption performance and surface energy of the electrostatic adsorption films prepared in Examples 1-6 and Comparative Examples 1-5 were tested respectively. The surface resistance of the composite film before single-sided corona treatment was also measured. The results are shown in Table 1 below. The test methods involved are as follows:

[0093] Electromagnetic absorption performance test method:

[0094] The N5224A microwave vector network analyzer was used to conduct the tests in a microwave anechoic chamber in accordance with the specifications of GJB 2038A-2011.

[0095] Surface energy testing methods:

[0096] Two liquids, dichloromethane and deionized water, were selected. The water contact angle of the membrane was measured by the static drop method using a water contact angle meter. The surface energy of the membrane was calculated based on the different surface tension, dispersion component, polarization component and water contact angle of the two liquids.

[0097] Surface resistivity test method:

[0098] The membrane sample was placed at room temperature for a period of time, and the surface resistance of the membrane was tested using the four-probe method. The four probes were spaced 1 mm apart, and the test was performed in parallel for 6 times. The average value was taken.

[0099] Table 1. Summary of the performance of the membranes prepared in Examples 1-6 and Comparative Examples 1-5

[0100]

[0101] Comparing Example 1 and Comparative Example 1, it can be seen that adding a plasticizer can adjust the surface resistance of the pre-corona treatment film. Compared with the film without plasticizer, the surface resistance of the pre-corona treatment film in Example 1 increased by nearly 55.8%, which is more conducive to charge accumulation on the surface of the film after corona treatment. After adopting the same corona treatment process, the surface energy of the film after corona treatment in Example 1 increased by more than 34%. The results of Examples 1, 4, and 5 show that the surface energy of the film after corona treatment can be adjusted by changing the corona treatment process, such as the corona treatment voltage, frequency, and the number of electrodes of the corona treatment machine. When the corona treatment voltage is 15000V / m... 2When the corona treatment frequency is 25kHz and the number of electrodes in the corona treatment machine is 6, the surface energy of the membrane after corona treatment is the highest, and the accumulated charge is the most. The results of Example 1 and Comparative Example 4 show that if the applied voltage is too high, the membrane is easily broken down, resulting in the inability to effectively accumulate charge. The results of Comparative Example 3 show that the type of electromagnetic wave absorber has a significant impact on the overall absorption performance of the membrane. In Comparative Example 3, the lightweight carbon-based absorber graphene was replaced with carbonyl iron powder. The bulk density and specific surface area of ​​the two are very different. In the traditional resin system, the upper limit of filling lightweight carbon-based absorbers with large specific surface areas is nearly 30wt%, while the upper limit of filling ferromagnetic absorbers is nearly 85wt%. Moreover, due to the different absorption principles of the two, ferromagnetic absorbers often need to be added to more than 70wt% to have practical absorption performance. Therefore, the absorption performance of Comparative Example 3 is significantly lower than that of Example 1. Adjusting the thickness of the PVC interlayer can also adjust the overall absorption performance of the membrane. For example, in Example 6, when the thickness of the PVC interlayer is 580μm, the effective bandwidth of ≤-4dB is significantly improved, reaching 8.84GHz.

[0102] In summary, this invention combines electromagnetic wave absorption with convenient electrostatic adsorption. It utilizes co-extrusion technology to composite PVC and PP films with wave-absorbing capabilities, followed by corona treatment of the composite film to prepare a wave-absorbing membrane material with electrostatic adsorption. This membrane material possesses both excellent wave-absorbing performance and electrostatic adsorption capacity for substrates, enabling electrostatic adsorption onto the surfaces of most substrates. This not only facilitates the radar stealth requirements of land-based and underwater equipment during transportation and movement but also saves significant manpower and resources for performance verification testing of wave-absorbing materials on scaled-down or full-scale weapon systems, shortening product development and verification cycles.

[0103] It should be noted that the present invention is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments that have the same structure and perform the same effects as the technical concept within the scope of the present invention are included within the scope of the present invention. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of the present invention, are also included within the scope of the present invention.

Claims

1. A wave-absorbing film material with electrostatic adsorption function, characterized in that, The PVC film and the PP film compounded on both sides of the PVC film; The raw materials for preparing the PVC film include 15-30 parts of electromagnetic wave absorber, 65-80 parts of PVC resin particles and 4-10 parts of auxiliary agent by weight; the electromagnetic wave absorber includes carbon material type electromagnetic wave absorber; the auxiliary agent includes stabilizer and plasticizer, and the plasticizer includes one or both of fatty acid ester type plasticizer and phthalate type plasticizer; The raw materials for preparing the PP film include 70-85 parts of PP resin particles, 10-25 parts of filler and 4-10 parts of auxiliary agent by weight; the auxiliary agent includes toughening agent and lubricant. 2.The wave-absorbing film material with electrostatic adsorption function according to claim 1, characterized in that, The carbon material type electromagnetic wave absorber includes one or more of carbon nanotube, graphene, carbon black and silicon carbide. 3.The wave-absorbing film material with electrostatic adsorption function according to claim 1, characterized in that, The molecular weight of the PVC resin particles is 50-120 thousand, and the molecular weight of the PP resin particles is 80-150 thousand. 4.The wave-absorbing film material with electrostatic adsorption function of claim 1, wherein, The stabilizer includes one or more of lead salt stabilizer, metal soap stabilizer, organic tin stabilizer, organic antimony stabilizer and organic rare earth stabilizer.

5. The wave-absorbing film material with electrostatic adsorption function according to claim 1, characterized in that, The thickness ratio of the PVC film to the single layer of the PP film is (20-60):1; the total thickness of the wave-absorbing film material with electrostatic adsorption function is ≤600 μm, and the film thickness of the single layer of the PP film is ≤25 μm.

6. A method for preparing the wave-absorbing film material with electrostatic adsorption function according to any one of claims 1-5, characterized in that, The method comprises the following steps: S1, batching: uniformly mixing electromagnetic wave absorber, PVC resin particles and auxiliary agent to obtain PVC film initial material, and uniformly mixing PP resin particles, filler and auxiliary agent to obtain PP film initial material; S2, co-extrusion: co-extruding the PVC film initial material and the PP film initial material, controlling the extrusion temperature of the PVC film initial material to be 110-120 ℃, the extrusion temperature of the PP film initial material to be 160-170 ℃, and extruding and stretching the molten material to form a PVC film and a PP film compounded on both sides of the PVC film to form an initial composite film; S3, single-sided corona treatment: the initial composite film is subjected to single-sided corona treatment to obtain a wave-absorbing film material with electrostatic adsorption function; the voltage applied in the corona treatment is 10000 V / m 2 15000 V / m 2 , the frequency is 15-25 kHz, and the electrode gap is ≤3 mm.

7. The method for preparing a microwave absorbing film material with electrostatic adsorption function according to claim 6, characterized in that, The corona treatment in step S3 adopts single-head or multi-head electrode.

8. The method for preparing a microwave absorbing film material with electrostatic adsorption function according to claim 7, characterized in that, The corona treatment in step S3 adopts 6-head electrode.

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