Wave-absorbing film material with electrostatic adsorption function and preparation method thereof

Abstract

The invention provides a wave-absorbing film material with an electrostatic adsorption function and a preparation method thereof, and belongs to the field of functional film materials. The wave-absorbing film material with the electrostatic adsorption function comprises a PVC (Polyvinyl Chloride) film and PP (Polypropylene) films compounded on two sides of the PVC film, wherein the PVC film is prepared from the following raw materials: an electromagnetic wave absorbent, PVC resin granules and an auxiliary agent; the electromagnetic wave absorbent comprises a carbon material type electromagnetic wave absorbent; the auxiliaries comprise a stabilizer and a plasticizer; the preparation raw materials of the PP film comprise PP resin pellets, a filler and an auxiliary agent. The auxiliaries comprise a toughening agent and a lubricating agent. The PVC film and the PP film with the wave-absorbing function are compounded and molded through a co-extrusion technology, and then the composite film is subjected to corona treatment to prepare the wave-absorbing film material with the electrostatic adsorption function, and the wave-absorbing film material has good insulativity, excellent electrostatic adsorption capacity, relatively high surface energy and excellent wave-absorbing performance; and the requirements of different use environments can be met.

Description

Technical Field

[0001] The present invention relates to the technical field of functional film materials, and in particular to a wave-absorbing film material with an electrostatic adsorption function and a preparation method thereof. Background Art

[0002] In the civilian field, the rapid development of technologies such as electrification has led to increasingly serious electromagnetic pollution in production and life, which not only causes mutual interference between equipment, but also causes irreversible damage to human health. In the military field, the advancement of detection methods such as radar and infrared has made it increasingly clear that weapons and equipment are "destroyed once discovered". How to improve the battlefield survivability of weapons and equipment has become a focus of attention for all countries. In this context, absorbing materials and stealth technology have become the key to overcoming such problems.

[0003] Compared with the stealth in appearance and structure, it is simpler and more feasible to absorb electromagnetic waves by coating absorbing paint and pasting absorbing patches, and it is easy to construct and not bound by the external environment. At present, whether it is for civilian or military absorbing materials, first of all, it is necessary to calculate the absorbing performance required by the material according to the background environment of the application; secondly, in the electromagnetic simulation software, based on the iterative calculation of a large amount of data, the electromagnetic parameters required by the absorbent under the absorbing performance are obtained; finally, the absorbent that meets the requirements is used to prepare samples at the corresponding concentration, and the test is carried out according to the standard, and the simulation results are corrected according to the measured values. If it is applied to the military field, on this basis, it is also necessary to use this material to construct on the proportional or scaled model of weapons and equipment to test the actual absorbing or stealth effect. Because the appearance structure of weapons and equipment itself has a certain stealth effect, after the superposition of absorbing materials, its stealth performance will change nonlinearly.

[0004] After the construction of absorbing materials on a proportional or scaled model, the performance often deviates, and the materials need to be optimized before construction and testing again, or the model needs to be used for other purposes. This requires the removal of the absorbing materials that have been coated or pasted by scraping, heating, tearing off, grinding, etc. These methods will consume a lot of manpower and material resources, especially for large stealth fighters and ships, the workload is unimaginable. In addition, in the transportation and movement of land equipment and underwater equipment before arriving at the battlefield, they also need to be treated as stealth. The commonly used packaging camouflage nets can only achieve optical camouflage, but cannot achieve radar undetectability. Therefore, there are certain disadvantages. Such problems also exist in the civilian field. For example, the outer surface of large medical equipment needs to absorb or shield electromagnetic waves to avoid mutual interference between equipment or harm to the human body. If a thick absorbing coating is applied, it will greatly affect its heat dissipation effect and reduce its service life.

[0005] Therefore, how to more conveniently realize the application of absorbing materials in the above situations is a problem that needs to be solved urgently. Summary of the invention

[0006] In view of the technical problems existing in the background technology, the present invention provides an absorbing film material with electrostatic adsorption function and a preparation method thereof, aiming to solve the technical problem of providing a film material having both absorbing and electrostatic adsorption functions.

[0007] In a first aspect, the present invention provides an absorbing film material with an electrostatic adsorption function, comprising a PVC film and a PP film composited on both sides of the PVC film; Among them, the raw materials for preparing the PVC film include electromagnetic wave absorbers, PVC resin granules and additives; the electromagnetic wave absorbers include carbon material electromagnetic wave absorbers; The raw materials for preparing PP film include PP resin pellets, fillers and additives; 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; The additives in the PP film include a toughening agent and a lubricant.

[0008] In the present invention, a PVC film with an absorbing function is combined with an electrostatic adsorption method, and the PVC film with an absorbing function is used as an intermediate layer, and PP films with high surface resistance values ​​are used as two side layers to prepare an absorbing film material with an electrostatic adsorption function. The absorbing film material has good insulation, excellent electrostatic adsorption capacity and high surface energy, can achieve electrostatic adsorption on the surface of most substrates, and can adapt to the requirements of different use environments.

[0009] The film material with electrostatic adsorption function is a film material that does not need to be coated with glue, but relies on its own electrostatic adsorption to adhere to the surface of the substrate, and plays a certain functional and protective role. It can be reused many times, especially for smooth surfaces such as glass, metal, and acrylic. It can show strong adhesion. The surface resistance of the film before corona can be adjusted by adding plasticizers. The surface resistance will affect the charge accumulation on the surface of the film after corona, and then affect its electrostatic adsorption ability.

[0010] 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 pellets and 4-10 parts of auxiliary agents; by weight, the raw materials for preparing the PP film include: 70-85 parts of PP resin pellets, 10-25 parts of fillers and 4-10 parts of auxiliary agents.

[0011] Preferably, the carbon material 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, rapid optimization and adjustment of the wave absorbing performance of the membrane material can be achieved.

[0012] Preferably, the molecular weight of the PVC resin pellets is 50,000 to 120,000; the molecular weight of the PP resin pellets is 80,000 to 150,000.

[0013] Preferably, the stabilizer in the raw material for preparing the PVC film comprises one or more of a lead salt stabilizer, a metal soap stabilizer, an organic tin stabilizer, an organic antimony stabilizer, and an organic rare earth stabilizer; including but not limited to the zinc stearate metal soap stabilizer listed in the embodiments of the present invention, and those skilled in the art may also replace it with other conventional lead salt stabilizers, metal soap stabilizers, organic tin stabilizers, organic antimony stabilizers, and organic rare earth stabilizers in the field of polymer film materials according to actual conditions and needs.

[0014] In the present invention, the filler in the raw material for preparing the PP film can be a conventional filler in the art, such as one or more combinations of talcum powder and white carbon black, which is used to reinforce the PP film and reduce material costs.

[0015] In the present invention, the toughening agent in the raw material for preparing the PP film can be a conventional toughening agent in the art, such as one or more combinations of POE (polyolefin elastomer), EPDM (ethylene-propylene-diene terpolymer) and EPR (ethylene-propylene binary copolymer).

[0016] In the present invention, the lubricant in the raw material for preparing the PP film may be a conventional lubricant in the art, such as one or more combinations of oxidized polyethylene wax and polyethylene wax.

[0017] Preferably, the thickness ratio of the PVC film to the single-layer PP film is (20-60):1; the total thickness of the absorbing film material with electrostatic adsorption function is ≤600μm, and the film thickness of the single-layer PP film is ≤25μm. By adjusting the thickness of the middle layer PVC film and the two side layers of PP film, the absorbing performance of the film material can be quickly optimized and adjusted.

[0018] In a second aspect, the present invention provides a method for preparing an absorbing film material having an electrostatic adsorption function, comprising the following steps: S1. Mixing ingredients: mixing the electromagnetic wave absorber, PVC resin pellets and additives to obtain the PVC film initial material, and mixing the PP resin pellets, fillers and additives to obtain the PP film initial material; S2, co-extrusion: co-extrude the PVC film initial material and the PP film initial material, control the extrusion temperature of the PVC film initial material to be 110° C.-120° C., and the extrusion temperature of the PP film initial material to be 160° C.-170° C., extrude and stretch the co-extruded molten materials to obtain 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: performing single-sided corona treatment on the initial composite film to obtain an absorbing film material with electrostatic adsorption function.

[0019] In the present invention, a PVC film with wave-absorbing function is used as the middle layer, and a PP film with a high surface resistance value is used as the two side layers. Three extruders are used to co-extrude a three-layer composite film, and then the corona technology is used to adjust the appropriate corona process, such as voltage, frequency, number of electrodes, etc., to prepare a wave-absorbing film material with electrostatic adsorption function. The wave-absorbing performance of the composite film can be adjusted and optimized by changing the thickness of the PVC film, the type and amount of the absorbent, etc.; single-sided corona technology treatment can make the outermost layer of the composite film accumulate a certain amount of charge, giving it an electrostatic force.

[0020] Preferably, the co-extrusion in step S2 is performed using an extruder, wherein the middle layer PVC film uses one extruder, and the two side layer PP films each use one extruder, for a total of three extruders.

[0021] Preferably, the voltage applied during the corona treatment in step S3 is 10000 V / m 2 ~15000V / m 2 , frequency is 15~25kHz, and electrode gap is ≤3mm.

[0022] 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.

[0023] The present invention can adjust the surface energy of the film after corona treatment by changing the corona process, such as the corona treatment voltage, frequency and number of electrodes, so as to achieve electrostatic adsorption of different substrates.

[0024] The main mechanism of the technical solution of the present invention is: introducing electromagnetic wave absorbers into the PVC film to make it have wave absorbing function, and the wave absorbing performance of the composite film can be adjusted and optimized by changing the thickness of the PVC film, the type and amount of the absorber, etc.; introducing plasticizers, toughening agents, etc. into the PVC film and the PP film to make them have high surface resistance values, which can improve the electrostatic adsorption capacity after corona treatment; preparing a three-layer composite film (PVC film as the middle layer, 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 obtained composite film material has both wave absorbing function and electrostatic adsorption function.

[0025] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention provides an absorbing film material with electrostatic adsorption function, comprising a PVC film and a PP film compounded on both sides of the PVC film to form a three-layer sandwich structure, wherein the middle layer is a PVC film with absorbing function, and the two side layers are ordinary PP films. The three are compounded by co-extrusion technology, and then the composite film is corona treated to prepare an absorbing film material with electrostatic adsorption function. The film material has both excellent absorbing performance and electrostatic adsorption ability to the substrate, and can achieve electrostatic adsorption on the surface of most substrates.

[0026] (2) The preparation process of the present invention is simple. By adjusting the thickness of the middle layer PVC film and the type and amount of absorbent, the wave absorbing performance of the film material can be quickly optimized and adjusted. By adjusting the corona 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 to adapt to the requirements of different substrate types and usage environments.

[0027] (3) The absorbing film material with electrostatic adsorption function provided by the present invention has broad application prospects. It can be conveniently and quickly attached to the surface of weapons and equipment. When the weapons and equipment are transported to the specified location, the electrostatic absorbing film can also be conveniently removed. It can replace the spraying of absorbing paint, pasting of absorbing patches and other methods, and quickly and seamlessly carry out performance testing and verification of absorbing materials on scale or scaled models of weapons and equipment. It can be suitable for adsorption on the outer surface of large medical equipment, reduce the interference between electromagnetic waves of different equipment and the harm to the human body, and avoid the disadvantages of poor heat dissipation caused by materials such as absorbing coatings and absorbing patches. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a front view of the absorbing film material with electrostatic adsorption function in Example 1 of the present invention. DETAILED DESCRIPTION

[0029] The following embodiments of the technical solution of the present invention are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and are therefore only used as examples, and cannot be used to limit the protection scope of the present invention.

[0030] The experimental methods without specific conditions in the examples are usually carried out according to conventional conditions and conditions described in the manual, or according to conditions recommended by the manufacturer. The general equipment, materials, reagents, etc. used are all available from commercial channels unless otherwise specified.

[0031] Example 1 A wave-absorbing film material with electrostatic adsorption function comprises a PVC film and a PP film compounded on both sides of the PVC film. The film material is a three-layer sandwich structure, wherein the middle layer is a PVC film with wave-absorbing function, and the two side layers are ordinary PP films.

[0032] The middle layer PVC film with wave absorbing function includes the following raw materials in parts by weight: electromagnetic wave absorber: 25 parts, PVC resin granules: 70 parts, and auxiliary agents: 5 parts; the electromagnetic wave absorber is graphene; the resin granules are PVC granules with a molecular weight of 80,000 to 100,000; the auxiliary agents are zinc stearate (metal soap stabilizer) and dioctyl phthalate (DOP) (phthalate plasticizer), and the ratio of the two is 2:3.

[0033] Each layer of PP film includes the following raw materials in parts by weight: 75 parts of PP resin pellets, 20 parts of fillers, and 5 parts of additives; among them, the PP resin pellets are PP pellets with a molecular weight of 100,000 to 120,000; the filler is talcum powder; the additives are POE (polyolefin elastomer) (toughener) and oxidized polyethylene wax (lubricant), and the ratio of the two is 2:3.

[0034] The method for preparing the wave-absorbing film material having an electrostatic adsorption function comprises the following steps: 1) Batching: respectively prepare the raw materials of PVC film and PP film according to the designed ratio and mix them evenly; 2) Raw material loading: Add the evenly mixed raw materials into the feed ports of their respective extruders. The middle layer PVC film uses one extruder, and the two side layer PP films each use one extruder, for a total of three extruders; 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 co-extruded molten resin passes through the metering pump and filter in turn, and finally enters the die head for extrusion and stretching molding; 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 15000 V / m 2 , the frequency is 25kHz, the electrode gap does not exceed 3mm, and 6-head electrodes are used; 5) Roll cutting: The final prepared absorbing film material with electrostatic adsorption function is rolled into film.

[0035] In this embodiment, the prepared wave-absorbing film with electrostatic adsorption function is a three-layer film structure, the thickness of the middle layer PVC film is 550 μm, and the thickness of the two side layers PP film is 25 μm. Figure 1 shown.

[0036] Example 2 A wave-absorbing film material with electrostatic adsorption function comprises a PVC film and a PP film compounded on both sides of the PVC film. The film material is a three-layer sandwich structure, wherein the middle layer is a PVC film with wave-absorbing function, and the two side layers are ordinary PP films.

[0037] The middle layer PVC film with wave absorbing function includes the following raw materials in parts by weight: electromagnetic wave absorber: 15 parts, PVC resin granules: 65 parts, and auxiliary agents: 4 parts; the electromagnetic wave absorber is carbon nanotubes; the resin granules are mixed PVC granules with a molecular weight of 50,000 to 70,000 and a molecular weight of 100,000 to 120,000, and the ratio of the two is 1:1; the auxiliary agents are tribasic lead sulfate (lead salt stabilizer) and di(2-ethylhexyl) azelaic acid (DOZ) (fatty acid ester plasticizer), and the ratio of the two is 2:3.

[0038] Each layer of PP film includes the following raw materials in parts by weight: 70 parts of PP resin pellets, 10 parts of fillers, and 4 parts of additives; among them, the PP resin pellets are mixed PP pellets with single molecular weights of 80,000 to 100,000 and 130,000 to 150,000, and the ratio of the two is 1:1; the filler is white carbon black; the additives are POE (polyolefin elastomer) (toughener) and polyethylene wax (lubricant), and the ratio of the two is 2:3.

[0039] The method for preparing the wave-absorbing film material having an electrostatic adsorption function comprises the following steps: 1) Batching: respectively prepare the raw materials of PVC film and PP film according to the designed ratio and mix them evenly; 2) Raw material loading: Add the evenly mixed raw materials into the feed ports of their respective extruders. The middle layer PVC film uses one extruder, and the two side layer PP films each use one extruder, for a total of three extruders; 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 co-extruded molten resin passes through the metering pump and filter in turn, and finally enters the die head for extrusion and stretching molding; 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 15000 V / m 2 , the frequency is 25kHz, the electrode gap does not exceed 3mm, and 6-head electrodes are used; 5) Roll cutting: The final prepared absorbing film material with electrostatic adsorption function is rolled into film.

[0040] In this embodiment, the prepared wave-absorbing film with electrostatic adsorption function is a three-layer film structure, the thickness of the middle layer PVC film is 550 μm, and the thickness of the two side layers PP film is 25 μm.

[0041] Example 3 A wave-absorbing film material with electrostatic adsorption function comprises a PVC film and a PP film compounded on both sides of the PVC film. The film material is a three-layer sandwich structure, wherein the middle layer is a PVC film with wave-absorbing function, and the two side layers are ordinary PP films.

[0042] The middle layer PVC film with wave absorbing function includes the following raw materials in parts by weight: electromagnetic wave absorber: 30 parts, PVC resin granules: 80 parts, and auxiliary agents: 10 parts; the electromagnetic wave absorber is graphene; the resin granules are PVC granules with a molecular weight of 100,000 to 120,000; the auxiliary agents are zinc stearate (metal soap stabilizer), dioctyl phthalate (DOP) (phthalate plasticizer) and di(2-ethylhexyl) azelaic acid (DOZ) (fatty acid ester plasticizer), and the ratio of the three is 2:2:1.

[0043] Each layer of PP film includes the following raw materials in parts by weight: 85 parts of PP resin pellets, 25 parts of fillers, and 10 parts of additives; among them, the PP resin pellets are PP pellets with a molecular weight of 100,000 to 120,000; the filler is talcum powder; the additives are POE (polyolefin elastomer) (toughener) and oxidized polyethylene wax (lubricant), and the ratio of the two is 2:3.

[0044] The method for preparing the wave-absorbing film material having an electrostatic adsorption function comprises the following steps: 1) Batching: respectively prepare the raw materials of PVC film and PP film according to the designed ratio and mix them evenly; 2) Raw material loading: Add the evenly mixed raw materials into the feed ports of their respective extruders. The middle layer PVC film uses one extruder, and the two side layer PP films each use one extruder, for a total of three extruders; 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 co-extruded molten resin passes through the metering pump and filter in turn, and finally enters the die head for extrusion and stretching molding; 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 15000 V / m 2 , the frequency is 25kHz, the electrode gap does not exceed 3mm, and 6-head electrodes are used; 5) Roll cutting: The final prepared absorbing film material with electrostatic adsorption function is rolled into film.

[0045] In this embodiment, the prepared wave-absorbing film with electrostatic adsorption function is a three-layer film structure, the thickness of the middle layer PVC film is 550 μm, and the thickness of the two side layers PP film is 25 μm.

[0046] Comparative Example 1 The only difference from Example 1 is that the additive in the PVC film raw material does not contain a plasticizer, and the other steps and conditions are the same as those of Example 1. In this comparative example, the thickness of the middle layer PVC film is 550 μm, and the thickness of the two side layers PP film is 25 μm.

[0047] Comparative Example 2 The only difference from Example 1 is that the PVC film includes the following raw materials by weight: 5 parts of electromagnetic wave absorber, 95 parts of PVC resin granules, and 5 parts of auxiliary agents; the PP film includes the following raw materials by weight: 85 parts of PP resin granules, 15 parts of fillers, and 15 parts of auxiliary agents. The other steps and conditions are the same as those in Example 1. In this comparative example, the thickness of the middle layer PVC film is 550 μm, and the thickness of the PP films on both sides is 25 μm.

[0048] Comparative Example 3 The only difference from Example 1 is that the electromagnetic wave absorber in this example is carbonyl iron powder, and the other steps and conditions are the same as those in Example 1. The thickness of the middle layer PVC film is 550 μm, and the thickness of the two side layers PP film is 25 μm.

[0049] Example 4 The only difference from Example 1 is that in this example, the single-sided corona treatment is performed on the prepared three-layer film using a corona treatment machine, and the applied voltage is 12000 V / m 2 , the frequency is 15kHz, the electrode gap does not exceed 3mm, and 6-head electrodes are used; other steps and conditions are the same as in Example 1.

[0050] In this embodiment, the thickness of the middle layer PVC film is 550 μm, and the thickness of the two side layers PP film is 25 μm.

[0051] Example 5 The only difference from Example 1 is that in this example, the single-sided corona treatment is performed: the prepared three-layer film is subjected to single-sided corona treatment using a corona treatment machine, and the applied voltage is 15000 V / m 2 , the frequency is 25kHz, the electrode gap does not exceed 3mm, and a single-head electrode is used; other steps and conditions are the same as in Example 1.

[0052] In this embodiment, the thickness of the middle layer PVC film is 550 μm, and the thickness of the two side layers PP film is 25 μm.

[0053] Comparative Example 4 The only difference from Example 1 is that the single-sided corona treatment is performed on the prepared three-layer film using a corona treatment machine, and the applied voltage is 18000V / m 2, the frequency is 30kHz, the electrode gap does not exceed 3mm, and 6-head electrodes are used; other steps and conditions are the same as in Example 1.

[0054] In this embodiment, the thickness of the middle layer PVC film is 550 μm, and the thickness of the two side layers PP film is 25 μm.

[0055] Example 6 The only difference from Example 1 is that in this embodiment, the thickness of the middle layer PVC film is 580 μm, and the thickness of the two side layers PP films is 10 μm.

[0056] Comparative Example 5 The only difference from Example 1 is that the thickness of the middle layer PVC film is 500 μm, and the thickness of the two side layers PP films is 50 μm.

[0057] Test example The electromagnetic wave absorbing performance and surface energy of the wave absorbing films with electrostatic adsorption function prepared in Examples 1 to 6 and Comparative Examples 1 to 5 were tested respectively, and the surface resistance value of the composite film before single-sided corona treatment was tested. The results are shown in Table 1 below. The test methods involved are as follows: Electromagnetic wave absorption performance test method: The test was carried out in a microwave darkroom using a N5224A microwave vector network analyzer in accordance with GJB 2038A-2011.

[0058] Surface energy test method: Two liquids, dichloromethane and deionized water, were selected, and the water contact angle of the membrane was measured using a water contact angle meter through a sessile drop method. The surface energy of the membrane was calculated based on the different tension values, dispersion components, polarization components and water contact angle values ​​of the two liquids.

[0059] Surface resistance test method: The film sample was placed at room temperature for a period of time, and the surface resistance of the film was tested by a four-probe method. The distance between the four probes was 1 mm, and the test was conducted in parallel 6 times to take the average value.

[0060] Table 1 Summary of properties of the films prepared in Examples 1 to 6 and Comparative Examples 1 to 5

[0061] By comparing Example 1 and Comparative Example 1, it can be seen that the surface resistance of the film before corona can be adjusted by adding a plasticizer. Compared with the case without adding a plasticizer, the surface resistance of the film before corona in Example 1 increases by nearly 55.8%, which is more conducive to the accumulation of charges on the surface of the film after corona. After adopting the same corona process, the surface energy of the film after corona in Example 1 increases by more than 34%. The results of Example 1, Example 4 and Example 5 show that the surface energy of the film after corona can be adjusted by changing the corona 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 2 , when the corona treatment frequency is 25kHz and the number of electrodes of the corona treatment machine is 6 levels, the surface energy of the film 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 film is easily broken down, resulting in the inability to effectively accumulate charges. The results of Comparative Example 3 show that the type of electromagnetic wave absorber has a significant effect on the overall wave absorption performance of the film. In Comparative Example 3, the lightweight carbon-based absorber graphene is replaced with carbonyl iron powder. The body density and specific surface area of ​​the two are very different. In the traditional resin system, the upper limit of the filling of lightweight carbon-based absorbers with large specific surface areas is nearly 30wt%, while the upper limit of the filling of ferromagnetic absorbers is nearly 85wt%, and due to the different wave absorption principles of the two, ferromagnetic absorbers often need to be added more than 70wt% to have more practical wave absorption performance. Therefore, the wave absorption performance of Comparative Example 3 is significantly lower than that of Example 1. Adjusting the thickness of the PVC intermediate film can also adjust the overall wave absorption performance of the film. As in Example 6, when the thickness of the PVC intermediate film is 580μm, the effective bandwidth of ≤-4dB is significantly improved to 8.84GHz.

[0062] In summary, the present invention combines the electromagnetic wave absorbing function with the convenient electrostatic adsorption method, and composites the PVC film and PP film with the absorbing function by co-extrusion technology, and then performs corona treatment on the composite film to prepare the absorbing film material with the electrostatic adsorption function. The film material has both excellent absorbing performance and electrostatic adsorption ability to the substrate, and can achieve electrostatic adsorption on the surface of most substrates. It not only facilitates the demand for radar stealth performance of land equipment, underwater equipment, etc. during transportation and movement, but also can save a lot of manpower and material resources for the performance verification test of absorbing materials on equal-scale or scaled models of weapons and equipment, and shorten the product development and verification cycle.

[0063] It should be noted that the present invention is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and the embodiments having the same structure as the technical idea and exerting the same effect within the scope of the technical solution of the present invention are all included in the technical scope of the present invention. In addition, without departing from the scope of the main purpose of the present invention, various modifications that can be thought of by those skilled in the art to the embodiments and other methods of combining some of the constituent elements in the embodiments are also included in the scope of the present invention.

Claims

1. A wave absorbing film material with electrostatic adsorption function, characterized in that: It includes a PVC film and a PP film compounded on both sides of the PVC film; The raw materials for preparing the PVC film include an electromagnetic wave absorber, PVC resin granules and an auxiliary agent; the electromagnetic wave absorber includes an electromagnetic wave absorber of a carbon material type; the auxiliary agent includes a stabilizer and a plasticizer, and the plasticizer includes one or two of a fatty acid ester plasticizer and a phthalate plasticizer; The raw materials for preparing the PP film include PP resin granules, fillers and additives; the additives include toughening agents and lubricants.

2. The wave-absorbing film material with electrostatic adsorption function according to claim 1, characterized in that: The raw materials for preparing the PVC film include, by weight: 15 to 30 parts of electromagnetic wave absorber, 65 to 80 parts of PVC resin granules and 4 to 10 parts of auxiliary agent; The raw materials for preparing the PP film include, by weight: 70-85 parts of PP resin pellets, 10-25 parts of fillers and 4-10 parts of additives.

3. The wave-absorbing film material with electrostatic adsorption function according to claim 1, characterized in that: The carbon material-based electromagnetic wave absorber includes one or more of carbon nanotubes, graphene, carbon black, and silicon carbide.

4. The wave-absorbing film material with electrostatic adsorption function according to claim 1, characterized in that: The molecular weight of the PVC resin pellets is 50,000 to 120,000; the molecular weight of the PP resin pellets is 80,000 to 150,000.

5. The wave-absorbing film material with electrostatic adsorption function according to claim 1, characterized in that: The stabilizer comprises one or more of a lead salt stabilizer, a metal soap stabilizer, an organic tin stabilizer, an organic antimony stabilizer, and an organic rare earth stabilizer.

6. 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 PP film is (20-60):1; the total thickness of the absorbing film material with electrostatic adsorption function is ≤600μm, and the film thickness of the single-layer PP film is ≤25μm.

7. A method for preparing an absorbing film material with electrostatic adsorption function as claimed in any one of claims 1 to 6, characterized in that: The following steps are involved: S1. Mixing ingredients: mixing the electromagnetic wave absorber, PVC resin pellets and additives to obtain the PVC film initial material, and mixing the PP resin pellets, fillers and additives to obtain the PP film initial material; S2, co-extrusion: co-extrude the PVC film initial material and the PP film initial material, control the extrusion temperature of the PVC film initial material to be 110° C.-120° C., and the extrusion temperature of the PP film initial material to be 160° C.-170° C., extrude and stretch the co-extruded molten materials to obtain 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: performing single-sided corona treatment on the initial composite film to obtain an absorbing film material with electrostatic adsorption function.

8. The method for preparing a wave-absorbing film material with electrostatic adsorption function according to claim 7, characterized in that: The voltage applied during the corona treatment in step S3 is 10000 V / m 2 ~15000V / m 2 , frequency is 15~25kHz, and electrode gap is ≤3mm.

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

10. The method for preparing a wave-absorbing film material with electrostatic adsorption function according to claim 9, characterized in that: The corona treatment in step S3 uses 6 electrodes.

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