CN109788728B - Light wave-absorbing dark room pointed cone material and preparation method thereof - Google Patents
Light wave-absorbing dark room pointed cone material and preparation method thereof Download PDFInfo
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Abstract
The invention relates to the technical field of wave-absorbing materials, in particular to a light wave-absorbing darkroom pointed cone material and a preparation method thereof. The light wave-absorbing darkroom sharp cone material is a cellular sharp cone structure formed by assembling flexible base materials, and the surface of the cellular sharp cone structure is provided with the graphene conductive coating, so that the light wave-absorbing darkroom sharp cone material is low in cost, high in mechanical strength, low in density, long in service life, good in performance, convenient to shrink, store and reduce the transportation cost and the storage space, and is beneficial to construction and use of a confidential test outfield; the preparation process has high production efficiency and low equipment cost, is suitable for mass production, and realizes the automation of the whole production line by arranging and linking the processes.
Description
Technical Field
The invention relates to the technical field of wave-absorbing materials, in particular to a light wave-absorbing darkroom pointed cone material and a preparation method thereof.
Background
The existing wave-absorbing darkroom pointed cone material mainly takes polyurethane foam (sponge) impregnated conductive carbon black slurry as a main material, in practical application, in order to improve the flame retardant property of the material, the material is usually realized by adding inorganic adhesive and inorganic flame retardant, the mode leads to the increase of the density of the wave-absorbing darkroom pointed cone material, when the material is required to be hung on a vertical wall for use, the material can deform and bend downwards due to dead weight, the normal use of the wave-absorbing material is influenced, meanwhile, the material has high density and large volume, and is not beneficial to outdoor use, and the application range is limited. In addition, because the working temperature of the polyurethane material is low, generally not more than 80 ℃, and the polyurethane material can soften and deform at high temperature, the average bearing power of the wave-absorbing dark room pointed cone material is 1 kilowatt/m2Within. The wave-absorbing material is one of the main construction costs of the wave-absorbing dark room, the service life of the wave-absorbing material becomes the restriction reason of the service life of the dark room, and the cost for replacing the wave-absorbing material is also high.
Chinese patent literature discloses a honeycomb pyramid wave-absorbing material based on graphene and a preparation method thereof, and the publication number is CN 108441067A. However, the density of the base material used by the invention is high, so that the base material is inconvenient to transport and store and is inconvenient for construction and use of a security test external field.
Disclosure of Invention
The invention provides a light wave-absorbing darkroom pointed cone material which is low in cost, high in mechanical strength, low in density, long in service life and good in performance, is convenient to shrink, store and reduce transportation cost and storage space, and is beneficial to construction and use of a confidential test outfield, in order to overcome the problems that a traditional wave-absorbing darkroom pointed cone material is large in size, high in density, low in mechanical strength, short in service life, poor in heat resistance, not suitable for outdoor use and not beneficial to environmental protection.
The invention also provides a preparation method of the light wave-absorbing darkroom pointed cone material, and the method is green and environment-friendly, has easily obtained raw materials and low cost, is easy to control process conditions, and is favorable for realizing large-scale industrial production.
In order to achieve the purpose, the invention adopts the following technical scheme:
the light wave-absorbing darkroom pointed cone material is provided with a cellular pointed cone structure formed by assembling flexible base materials, and a graphene conductive coating is arranged on the surface of the cellular pointed cone structure. The optimized wave-absorbing honeycomb structure is designed according to application requirements, the opening surface of the honeycomb facing to the incident direction can be a plane, and can also be a pointed cone and a pointed wedge so as to realize the lowest thickness and the optimal impedance matching, the opening angle of the honeycomb can be an oblique angle and any angle, and the angle is generally close to the incident angle.
The light wave-absorbing darkroom sharp cone material is convenient to fold, shrink, store and preserve by selecting the flexible material as the base material, reduces the transportation cost and the storage space, and is beneficial to the construction and the use of a security test outfield. The designed honeycomb-shaped pointed cone structure has higher mechanical strength, the graphene conductive coating arranged on the surface endows the honeycomb-shaped pointed cone structure with long service life and high power wave-absorbing performance, the service life of a darkroom can be prolonged, the microwave power range used by the darkroom is increased, and the use cost is reduced.
Preferably, the cellular pointed cone structure comprises a plurality of wave-absorbing cells; the wave absorbing honeycomb is a straight honeycomb or an oblique wedge honeycomb; the honeycomb included angle of the oblique wedge honeycomb is less than 70 degrees. The honeycomb structure can be shaped as long as low-cost producibility is achieved, such as regular hexagon, non-regular hexagon, square, rectangle, wave and the like, and similar honeycomb structures, such as quadrilateral structures formed by mutually and vertically inserting more than one half of two groups of same equidistant grooves. With dimensions from 0.3 cm to 20 cm, with common dimensions being 0.5 cm to 5 cm, and the height of the cell dimensions being proportional to the wavelength and bandwidth absorbed.
Preferably, the flexible base material is one or more of paper, cloth, a plastic film, a flexible foam board and a hard board which is bonded by the flexible base material to form a foldable structure; the thickness of the flexible base material is 0.01-5 mm.
Preferably, the flexible base material is one or more of flame-retardant kraft paper, a thin film, non-woven fabric, aramid fiber paper, glass fiber cloth and glass fiber paper; the surface density of the flexible base material is 20-500 g/m2。
The honeycomb prepared by paper has the long-term use temperature of 120 ℃, the short-time use temperature of 150 ℃, the service life of the paper can easily exceed 20 years, and the service life is as long as that of a metal structure in a dark room, and is even longer. The honeycomb composed of glass fiber cloth and inorganic adhesive has heat-resisting temperature higher than 450 deg.C, and the heat-resisting upper limit is determined by the heat-resisting temperature of the conductive wave-absorbing agent, so that the power density higher than 20 kilowatt/m can be realized2. The honeycomb has high self rigidity, can be prepared into a taper cone and a wedge cone and also can be prepared into a complex shape, and the high-efficiency wave absorption of high incident angle and dark room corner reflection is met.
Preferably, the equivalent surface resistance range of the graphene conductive coating is controlled to be 10-1000 ohms, and preferably 50-500 ohms.
A preparation method of a light wave-absorbing dark room pointed cone material comprises the following steps:
(1) optimizing the design and material selection of the honeycomb pointed cone structure, and determining the flexible base material, the electromagnetic parameters and the structural characteristics;
(2) uniformly coating a shaping adhesive on the surface of the flexible substrate, drying and curing; the shaping glue is conductive wave-absorbing shaping slurry or non-conductive wave-absorbing shaping slurry; the conductive wave-absorbing sizing slurry is graphene conductive slurry;
(3) rolling the flexible base material processed in the step (2) into a corrugation through a pair of heating gears according to design parameters, wherein the design parameters comprise the depth, the angle and the width of the corrugation; the heating temperature of the pressed corrugated pipe is more than 80 ℃; the corrugated base material is pressed by a double-roller rolling machine with a heater and a gear or a hot press with a corrugated die, and the shape, the depth, the width and the period length of the corrugation are design parameters, namely the design parameters of the honeycomb. The depth and the width are the side length of each side, the width is also the width of the contact surface, and the period length is the period of the honeycomb;
(4) coating adhesive glue on the mutual contact surfaces of the corrugations, arranging the corrugated; coating joint glue on the contact surface of the corrugated board by using a double-roller glue spreader, dipping a lower roller of the double-roller glue spreader in a glue tank, spreading glue liquid on the contact surface (glue joint surface) of the corrugated board, and providing pressure by an upper roller to ensure that the contact surface of the corrugated board is contacted with the lower roller; arranging and superposing the corrugations according to the honeycomb design to obtain a honeycomb block, then heating, curing, joint dispensing and gluing by using an oven capable of providing proper pressure for the honeycomb block, wherein the curing temperature and time are determined according to the curing requirement of glue, common joint glue is a phenolic aldehyde series, and the curing temperature is 180 ℃ for 30 min;
(5) cutting a pointed cone from the integrated honeycomb structure to obtain a pointed cone-shaped honeycomb structure;
(6) when the shaping adhesive used in the step (2) is non-conductive wave-absorbing shaping slurry, dipping or spraying graphene conductive slurry on the flexible base material with the cellular pointed cone structure obtained in the step (5), drying and curing to form a graphene conductive coating, and thus obtaining the light wave-absorbing dark room pointed cone material; when the shaping adhesive used in the step (2) is conductive wave-absorbing shaping slurry, the step is omitted;
(7) and (3) spraying or dipping the room-temperature curing light-color paint according to the requirements of customers.
The graphene conductive coating on the surface of the light wave-absorbing dark room pointed cone material can be coated on the surface of a flexible base material by dipping, and can also be formed by dipping a graphene conductive slurry after honeycomb forming in various forming modes. The invention provides a low-cost preparation process, wherein a low-cost honeycomb material is prepared by using flexible paper, a film or cloth, coating glue on the contact surface (honeycomb node) of a corrugation by dipping/coating the glue and shaping by a corrugating machine, bonding the corrugation together to form a honeycomb, and then cutting the honeycomb into a pointed cone or a split cone and various shapes to be dipped with conductive slurry. Or the conductive sizing adhesive is adopted, so that the honeycomb conductive slurry dipping process is omitted. The strength of the honeycomb material is far higher than that of light materials such as foam, the compression strength of the honeycomb material is one time of that of high-strength foam under the same density, the production process is mature, and the honeycomb structure material can be produced by using different paper, cloth, glass fiber cloth, plastic sheets and the like. The larger the diameter of the honeycomb section is, the lighter the honeycomb structure is, and the lower the cost is. Due to the high conductivity of the graphene, the wave-absorbing coating can be very thin, has good flexibility and better compatibility with paper, films and fiber cloth, and does not have the brittleness and the falling-off phenomenon of the carbon black coating. The angle of the corrugation can be designed according to requirements, namely the opening direction and angle of the honeycomb can be adjusted according to the design of the orientation of the corrugation, the honeycomb serving as a wave absorbing material means that the optimal wave absorbing incident angle can be optimized, and the cut pointed cone can be different pointed angles. Unlike polyurethane foam, the problem of bending deformation of foam cones does not occur even if the inclined pointed cone honeycomb is not vertical due to the high rigidity of the material. The corrugated paper box is a main packaging material, the technology is mature, the cost is low, the kraft paper of the raw material is only thousands of yuan per ton, the cost is lower than that of polyurethane sponge, the honeycomb prepared by the corrugated paper technology has obvious advantages in cost, and the product performance is far higher than that of the existing sponge wave-absorbing material, so that the light wave-absorbing dark room pointed cone material prepared by the invention is a wave-absorbing material with high cost performance and can replace sponge.
Preferably, in the step (1), the design and material selection of the honeycomb-shaped pointed cone structure adopt electromagnetic simulation software to optimize the shape and microwave electromagnetic property of the wave-absorbing slurry, and the electromagnetic property of the slurry is the composite dielectric constant and the thickness or simple surface complex sheet resistance. The design of the honeycomb is optimized by electromagnetic simulation software, the dielectric constant or surface sheet resistance, the size and shape of the honeycomb, the shape and thickness of the material and the like of the conductive coating film are input into a computer program for electromagnetic calculation and optimization, the program can be commercial software and self-programming program, common commercial software such as HFSS, XFDTD, CST and the like can be used for electromagnetic calculation, and special program can be self-programmed, so that the design is quickly optimized more effectively, and the rights and interests of the invention are not changed by using different software. The method comprises the steps of selecting a flexible base material, electromagnetic parameters and honeycomb structural characteristics for producing the honeycomb by adopting a finite element electromagnetic simulation design, wherein the selection parameters of the flexible base material comprise thickness and dielectric constant, the electromagnetic parameters comprise surface sheet resistance, and the honeycomb structural characteristics comprise honeycomb side length, honeycomb inclination angle, honeycomb height, pointed cone height, width and the like.
The optimization result of the invention discovers that: compared with conductive carbon black, metal powder, graphite powder and other conductive powder, the nano graphene and the composite of the nano graphene and the conductive carbon black have better effect as a conductive additive, and the upper limit of the use high frequency is one half wavelength of which the honeycomb size is less than the frequency. For high angle of incidence requirements, the cell's tilt angle is close to the angle of incidence for best performance. The performance requirements determine its minimum cell thickness, the cell tilt angle and the coating resistance distribution of the cell inner walls and the cell thickness determine the frequency response of absorption and sensitivity to incident angle.
The result of the optimization is the thinnest (lowest cell) design that meets the requirements, as well as coating thickness or surface sheet resistance and lowest cost. The cellular application frequency designed and produced by the invention is 0.01-110 GHz, and the bandwidth is optional. The optimum angle of incidence may be from normal incidence to 60 °.
Preferably, in the step (2) and the step (6), the viscosity of the graphene conductive paste ranges from 100 to 1000mPa · s; by taking the total mass of the graphene conductive paste as a reference, the graphene conductive paste consists of the following components in percentage by mass: 1-40% of graphene, 0-20% of conductive carbon black, 10-60% of water-based resin and the balance of solvent.
The conductive wave absorbing agent of the graphene conductive slurry is prepared from graphene and conductive carbon black, can be used independently or compositely, meets the performance and realizes the lowest cost. The conductive carbon black is acetylene black and high-conductivity carbon black treated at high temperature. The stoneThe graphene is a slurry prepared by taking graphite worms as a raw material by adopting a physical stripping method, wherein the graphite worms are prepared by heating expandable graphite in a high-temperature furnace, the heating expansion temperature is 600-1800 ℃, preferably 900-1200 ℃, the furnace atmosphere is inert gas, and high-temperature oxygen-free tail gas, nitrogen, argon and the like are obtained after combustion; the expandable graphite has expansion multiple of more than 400 times, and the specific surface area of the obtained graphite worms is more than 35m2(ii) in terms of/g. The invention can use any adhesive, which can be precursors of organic high molecular materials, inorganic materials and ceramics, and the usage amount in the formula is from 10% to 60%. The solvent is used for adjusting the producibility and the manufacturability, and is selected according to the type of the adhesive, the usage amount of the solvent in the formula is 0-80%, and the viscosity range of the slurry is 100-1000 mPa & s. Various auxiliaries may also be used for modifying the processability, etc., such as leveling agents, dispersing agents, etc.
Preferably, the aqueous resin is one or a mixture of more of aqueous phenolic aldehyde, polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), modified silicone resin, aqueous polyacrylic acid, aqueous epoxy, aqueous polyurethane, sepiolite and silica gel.
The aqueous slurry is more environment-friendly and safer to use, and is dried at room temperature and cured by heating after being impregnated according to the curing conditions of the resin. The honeycomb pointed cone with the wave absorbing performance is dipped or sprayed with protective finish according to the color requirements of customers, the coating can increase the brightness or camouflage of the using environment of the wave absorbing material, a water-resistant coating is not needed for indoor use, and preferably, the water-based emulsion paint, the water-based epoxy and the water-based polyurethane are environment-friendly coatings, and are dried and cured after being dipped or sprayed.
Preferably, in the step (2), the shaping glue is coated on the surface of the flexible base material by adopting a roll-to-roll process, the full-automatic continuous roll-to-roll impregnating, drying and curing process has high production efficiency and low equipment cost, is suitable for mass production, and is linked with subsequent corrugated heating rolling forming and honeycomb gluing arrangement to realize the automation of the whole production line.
Preferably, in the step (5), cutting a tip cone by a high-speed band saw; the linear speed of the high-speed band saw is more than 1000 m/min; preferably, the honeycomb is fixed on a mechanical arm, and the shape of the honeycomb is controlled by a computer program.
Therefore, the invention has the following beneficial effects:
(1) the light wave-absorbing darkroom sharp cone material is a cellular sharp cone structure formed by assembling flexible base materials, and the surface of the cellular sharp cone structure is provided with the graphene conductive coating, so that the light wave-absorbing darkroom sharp cone material is low in cost, high in mechanical strength, low in density, long in service life, good in performance, convenient to shrink, store and reduce the transportation cost and the storage space, and is beneficial to construction and use of a confidential test outfield;
(2) the preparation process has high production efficiency and low equipment cost, is suitable for mass production, and realizes the automation of the whole production line by arranging and linking the processes.
Drawings
FIG. 1 is a flow chart of a preparation process of the light wave-absorbing darkroom pointed cone material.
Fig. 2 is a flow chart of a preparation process of the graphene conductive paste of the present invention.
Fig. 3 is a schematic view of a rolling process of the corrugation.
Fig. 4 is a schematic structural diagram of a tilted honeycomb.
Fig. 5 is a schematic diagram of a structure of a straight honeycomb.
Fig. 6 is a schematic diagram of a honeycomb tip cone structure.
Fig. 7 is a schematic structural view of a kraft paper honeycomb block.
Fig. 8 is a structural schematic diagram of a kraft paper honeycomb pointed cone without a graphene conductive coating on the surface.
Fig. 9 is a structural schematic diagram of a kraft paper honeycomb pointed cone with a graphene conductive coating on the surface.
FIG. 10 is a cross-sectional view of one design of a beveled tip.
Detailed Description
The technical solution of the present invention is further specifically described below by using specific embodiments and with reference to the accompanying drawings.
In the present invention, all the equipment and materials are commercially available or commonly used in the art, and the methods in the following examples are conventional in the art unless otherwise specified.
Example 1: 300mm high 120 ℃ long-term use light wave-absorbing darkroom pointed cone material
(1) The production process is shown in figure 1, firstly, the electromagnetic simulation is adopted to optimally design the honeycomb pointed cone structure, and the flexible substrate is determined to have the surface density of 110g/m2The conductive wave absorbing agent is graphene, and the resin is water-soluble phenolic aldehyde; according to the electromagnetic simulation design, the total height H of the honeycomb is 300mm, the height H of a pointed cone is 220mm, the bottom width D is 100mm, in order to improve oblique incidence wave absorbing performance, oblique honeycombs are adopted, the angle of the honeycombs and an opening form a 15-degree angle, a layer of corrugated honeycombs is a positive 15-degree angle, an upper part and a lower part of the corrugated honeycombs are negative 15-degree angles, alternate superposition of the positive 15-degree angle and the negative 15-degree angle is formed, and symmetry of performance is ensured. The side length and the depth of the honeycomb are both 5mm, and the surface square resistance of the wave-absorbing honeycomb is 90 ohms;
(2) preparing graphene conductive paste with reference to fig. 2: firstly, 50-mesh expandable graphite with expansion multiple of 420 times is adopted to be expanded in an electric furnace protected by nitrogen at 1000 ℃ to obtain the specific surface area of 36m2Per gram of graphite worms. Feeding expandable graphite at the top of the furnace through a screw feeder, blowing expanded worms away from a high-temperature furnace at the bottom of the furnace to enter a vacuum kettle, mixing the expanded worms with deionized water, vacuumizing and degassing, wherein the weight ratio of the deionized water to the worms is 100: 5. stirring and mixing for 1-5 hours to obtain slurry, pumping the slurry to a high-shear colloid mill from the bottom of the kettle, carrying out circular stripping at a stripping shear speed of not less than 10000/s until the particle size of the graphene is less than 20 microns, and measuring the particle size by using a laser particle sizer. And adding water-soluble phenolic resin, a water-based dispersing agent and a defoaming agent to obtain the graphene phenolic aqueous slurry with the viscosity of about 800mPa & s. The weight ratio of the deionized water to the graphene to the phenolic resin to the dispersant to the defoamer is 100: 5: 15: 2: 0.5. the dispersing agent is water-based polyacrylic acid, and the defoaming agent is a siloxane compound, so that the graphene conductive slurry is obtained;
(3) referring to fig. 3, on a corrugated honeycomb roll-to-roll production line, kraft paper continuously passes through a 15% aqueous phenolic resin liquid tank, enters a 150 ℃ oven for drying, and passes through a 130 ℃ gear rolling mill to roll a 5mm corrugation according to the design;
(4) cutting the corrugated sheet into 15-degree oblique angles, coating 25% of water-based phenolic aldehyde joint glue on the contact surface through a double-roller glue spreader, then alternately superposing positive and negative 15-degree corrugations to form a honeycomb block, moving the honeycomb block into a drying oven, forming pressure of 0.01-0.1 kPa on the honeycomb block through a method of a heavy object and the like, and ensuring the bonding strength of the honeycomb contact surface (node). The oven temperature is 180 ℃, and the curing time is 60min to obtain the honeycomb block with the integrated honeycomb structure (see fig. 7);
(5) cutting the honeycomb block into 600x600x300mm, and then cutting one side of the honeycomb into 36 symmetrical pointed cones (see figure 8) with the depth of 220mm by using a high-speed electric band saw, wherein the linear speed of the band saw is more than 1000 m/min;
(6) dipping the pointed cone in the graphene conductive slurry prepared in the step (2) for 3min, taking out, airing at room temperature, and then curing in an oven at 180 ℃ for 60min to obtain the graphene pointed cone wave-absorbing honeycomb (see fig. 9);
(7) and (3) spraying or dipping the room-temperature curing light-color paint according to the requirements of customers.
The light wave-absorbing darkroom pointed cone material prepared by the embodiment can realize the wave-absorbing performance of 40dB above 2GHz, meets the flame-retardant level of flame retardant performance, and has an oxygen index greater than 28%.
Example 2: light wave-absorbing darkroom pointed cone material with height of 500mm and long-term use at 300 DEG C
(1) The production process is shown in figure 1, firstly, the electromagnetic simulation is adopted to optimally design the honeycomb pointed cone structure, and the flexible substrate is determined to have the surface density of 200g/m2The conductive wave absorbing agent is graphene, and the resin is modified silicon resin; according to the electromagnetic simulation design, the total height H of the honeycomb is 500mm, the height H of a pointed cone is 400mm, the bottom width D is 150mm, in order to improve oblique incidence wave absorbing performance, oblique honeycombs are adopted, the angle of the honeycombs and an opening form a 15-degree angle, a layer of corrugated honeycombs is a positive 15-degree angle, an upper part and a lower part of the corrugated honeycombs are negative 15-degree angles, alternate superposition of the positive 15-degree angle and the negative 15-degree angle is formed, and symmetry of performance is ensured. The side length and the depth of the honeycomb are both 5mm, and the surface square resistance of the wave-absorbing honeycomb is 100 ohms;
(2) preparing graphene conductive paste with reference to fig. 2: firstly, 50-mesh expandable graphite with expansion multiple of 420 times is adopted to be expanded in an electric furnace protected by nitrogen at 1000 ℃ to obtain the specific surface area of 36m2Per gram of graphite worms. The expandable graphite is fed in from the top of the furnace through a screwFeeding the material machine, blowing expanded worms from the high-temperature furnace at the bottom of the furnace to enter a vacuum kettle, mixing the expanded worms with deionized water, vacuumizing and degassing, wherein the weight ratio of the deionized water to the worms is 100: 5. stirring and mixing for 1-5h to obtain slurry, pumping the slurry to a high-shear colloid mill from the bottom of the kettle, carrying out circular stripping at a stripping shear speed of not less than 10000/s until the particle size of the graphene is less than 20 microns, and measuring the particle size by using a laser particle sizer. And adding the modified silicon resin, the water-based dispersing agent and the defoaming agent to obtain the graphene silicon resin slurry with the viscosity of about 600mPa & s. The weight ratio of the deionized water to the graphene to the modified silicon resin to the dispersing agent to the defoaming agent is 100: 5: 20: 2.5: 0.5. the dispersing agent is water-based polyacrylic acid, and the defoaming agent is a siloxane compound, so that the graphene conductive slurry is obtained;
(3) referring to fig. 3, on a corrugated honeycomb roll-to-roll production line, continuously passing glass fiber cloth through a graphene modified silicone liquid tank containing the graphene conductive slurry prepared in the step (2), drying in a drying oven at 150 ℃, and rolling a 5mm corrugation by a gear rolling mill at 150 ℃ according to design;
(4) cutting the corrugated sheet into 15-degree oblique angles, coating 25% of modified silicone resin node adhesive on the contact surface through a double-roller adhesive coating machine, then alternately superposing positive and negative 15-degree corrugations to form a honeycomb block, moving the honeycomb block into an oven, and forming pressure of 0.01-0.1 kPa on the honeycomb block through methods such as a heavy object and the like to ensure the bonding strength of the honeycomb contact surface (node). The oven temperature is 250 ℃, and the curing time is 60min to obtain a honeycomb block (see figure 4 or figure 5 or figure 6);
(5) cutting the honeycomb block into 600x600x500mm, and then cutting one side of the honeycomb into 16 symmetrical pointed cones with the depth of 400mm by using a high-speed electric band saw to obtain the graphene pointed cone wave-absorbing honeycomb;
(6) spraying or dipping the room temperature curing light-colored paint according to the requirements of customers;
the light wave-absorbing darkroom pointed cone material prepared by the embodiment can realize the wave-absorbing performance of 40dB above 1GHz, meet the incombustible level of flame retardant performance, and has an oxygen index greater than 60%.
Example 3: the production process of the wedge material (1) of the wedge light wave-absorbing darkroom with the oblique incidence wave-absorbing wedge and the honeycomb light wave-absorbing structure with the height of 400mm and the temperature of 80 ℃ for long-term use is shown in figure 1, firstly, the electromagnetic simulation is adopted to optimally design the honeycombThe surface density of the flexible substrate is determined to be 60g/m by adopting a pointed cone structure2The thickness of the polyester non-woven fabric is 100 mu m, the conductive wave absorbing agent is graphene, and the resin is modified phenolic resin; according to the electromagnetic simulation design, the total height H of the honeycomb is 400mm, the height H of a pointed cone is 300mm, the bottom width D is 120mm, in order to improve oblique incidence wave absorbing performance, an oblique honeycomb is adopted, one side of the pointed cone of the honeycomb is about 40 degrees, the other side of the pointed cone of the honeycomb is 52 degrees, the angle of the honeycomb and an opening form a 45-degree angle, the side length and the depth of the honeycomb are both 5mm, and the surface sheet resistance of the wave absorbing honeycomb is 100 ohms;
(2) preparing graphene conductive paste with reference to fig. 2: firstly, 50-mesh expandable graphite with the expansion multiple of 500 times is adopted to be expanded in an electric furnace protected by nitrogen at 950 ℃ to obtain the specific surface area of 41m2Per gram of graphite worms. Feeding expandable graphite at the top of the furnace through a screw feeder, blowing expanded worms away from a high-temperature furnace at the bottom of the furnace to enter a vacuum kettle, mixing the expanded worms with deionized water, vacuumizing and degassing, wherein the weight ratio of the deionized water to the worms to acetylene black is 100: 4.5: 2. stirring and mixing for 1-5 hours to obtain slurry, pumping the slurry to a high-shear colloid mill from the bottom of the kettle, carrying out circular stripping at a stripping shear speed of not less than 10000/s until the particle size of the graphene is less than 15 microns, and measuring the particle size by using a laser particle sizer. And adding the modified phenolic resin, the water-based dispersing agent and the defoaming agent to obtain the graphene silicon resin slurry with the viscosity of about 850mPa & s. The weight ratio of the deionized water to the graphene to the acetylene black to the modified phenolic resin to the dispersant to the defoamer is 100: 4.5: 2: 15.5: 2.5: 0.5. the dispersing agent is water-based polyacrylic acid, and the defoaming agent is a siloxane compound, so that the graphene conductive slurry is obtained;
(3) on a corrugated honeycomb roll-to-roll production line, continuously passing polyester non-woven fabric through a graphene modified phenolic resin liquid tank in which the graphene conductive slurry prepared in the step (2) is arranged, drying in a 120 ℃ oven, and rolling a 5mm corrugation by a 140 ℃ gear rolling mill according to design;
(4) cutting the corrugated sheet into 60-degree oblique angles, coating 20% of modified phenolic resin node adhesive on the contact surface through a double-roller adhesive coating machine, then alternately overlapping the corrugated sheets to form an oblique honeycomb block, moving the honeycomb block into a drying oven, and forming pressure of 0.01-0.03 kPa on the honeycomb block through methods such as a heavy object and the like to ensure the bonding strength of the honeycomb contact surface (node). The oven temperature is 150 ℃, and the curing time is 30min to obtain honeycomb blocks;
(5) cutting the honeycomb block into 600x800x400mm, and then cutting one side of the honeycomb into 5 300mm deep oblique wedges (see fig. 10) by using a high-speed electric band saw to obtain the graphene oblique wedge wave-absorbing honeycomb;
(6) spraying or dipping the room temperature curing light-colored paint according to the requirements of customers;
the light wave-absorbing darkroom pointed cone material prepared by the embodiment can realize the wave-absorbing performance of 40dB above an incident angle of 45 degrees and 2GHz, meets the flame-retardant level of flame retardant property, and has an oxygen index of more than 28%.
The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention in any way, and other variations and modifications may be made without departing from the spirit of the invention as set forth in the claims.
Claims (7)
1. The preparation method of the light wave-absorbing darkroom pointed cone material is characterized in that the light wave-absorbing darkroom pointed cone material is of a honeycomb-shaped pointed cone structure formed by assembling flexible base materials, and a graphene conductive coating is arranged on the surface of the honeycomb-shaped pointed cone structure; the flexible base material is one or more of flame-retardant kraft paper, a thin film, non-woven fabric, aramid fiber paper, glass fiber cloth and glass fiber paper; the surface density of the flexible base material is 20-500 g/m2；
The preparation method comprises the following steps:
(1) optimizing the design and material selection of the honeycomb pointed cone structure, and determining the flexible base material, the electromagnetic parameters and the structural characteristics;
(2) uniformly coating a shaping adhesive on the surface of the flexible substrate, drying and curing; the shaping glue is conductive wave-absorbing shaping slurry or non-conductive wave-absorbing shaping slurry; the conductive wave-absorbing sizing slurry is graphene conductive slurry; by taking the total mass of the graphene conductive paste as a reference, the graphene conductive paste consists of the following components in percentage by mass: 1-40% of graphene, 0-20% of conductive carbon black, 10-60% of water-based resin and the balance of solvent; the water-based resin is selected from one or more of water-based phenolic aldehyde, polyvinyl alcohol, polyvinylpyrrolidone, modified silicone resin, water-based polyacrylic acid, water-based epoxy, water-based polyurethane, sepiolite and silica gel; the viscosity range of the graphene conductive slurry is 100-1000 mPa & s;
(3) rolling the flexible base material processed in the step (2) into a corrugation through a pair of heating gears according to design parameters, wherein the design parameters comprise the depth, the angle and the width of the corrugation; the heating temperature of the pressed corrugated pipe is more than 80 ℃;
(4) coating adhesive glue on the mutual contact surfaces of the corrugations, arranging the corrugated;
(5) cutting a pointed cone from the integrated honeycomb structure to obtain a pointed cone-shaped honeycomb structure;
(6) when the shaping adhesive used in the step (2) is non-conductive wave-absorbing shaping slurry, dipping or spraying graphene conductive slurry on the flexible base material with the cellular pointed cone structure obtained in the step (5), drying and curing to form a graphene conductive coating, and thus obtaining the light wave-absorbing dark room pointed cone material; when the shaping adhesive used in the step (2) is conductive wave-absorbing shaping slurry, the step is omitted; the viscosity range of the graphene conductive slurry is 100-1000 mPa.
2. The preparation method of the light wave-absorbing dark room pointed cone material according to claim 1, characterized in that in the step (2), a roll-to-roll process is adopted to coat the shaping glue on the surface of the flexible base material.
3. The preparation method of the light wave-absorbing darkroom pointed cone material according to claim 1, characterized in that in the step (5), a pointed cone is cut by a high-speed band saw; the linear speed of the high-speed band saw is more than 1000 m/min.
4. A light wave-absorbing dark room pointed cone material prepared by the preparation method of any one of claims 1 to 3.
5. The light wave-absorbing darkroom pointed cone material of claim 4, wherein the cellular pointed cone structure comprises a plurality of wave-absorbing cells; the wave absorbing honeycomb is a straight honeycomb or an oblique wedge honeycomb; the honeycomb included angle of the oblique wedge honeycomb is less than 70 degrees.
6. The light wave-absorbing dark room pointed cone material of claim 4, wherein the thickness of the flexible base material is 0.01-5 mm.
7. The light wave-absorbing dark room pointed cone material according to claim 4, wherein the equivalent surface resistance range of the graphene conductive coating is controlled to be 10-1000 ohms.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000188513A (en) * | 1998-10-15 | 2000-07-04 | Riken Corp | Composite radio wave absorber and its working method |
| CN203795889U (en) * | 2014-03-27 | 2014-08-27 | 上海一航凯迈光机电设备有限公司 | Infrared-microwave composite darkroom |
| CN104735964A (en) * | 2015-02-02 | 2015-06-24 | 邓秀梅 | Microwave-absorbing material for microwave chamber and printing production method thereof |
| CN106903931A (en) * | 2017-02-24 | 2017-06-30 | 浙江大胜达包装股份有限公司 | Steam ladder utilizes system on corrugated paper production line |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2927154Y (en) * | 2006-07-14 | 2007-07-25 | 姜启涛 | Multifunctional environmental-protecting host box of computer |
| CN103289641B (en) * | 2013-06-08 | 2014-08-06 | 南京洛普电子工程研究所 | Multi-layer polyurethane flexible foam composite wave-absorbing material and preparation method thereof |
| CN108441067B (en) * | 2018-02-26 | 2020-04-17 | 北京环境特性研究所 | Graphene-based honeycomb pyramid wave-absorbing material and preparation method and application thereof |
| CN108966622A (en) * | 2018-08-10 | 2018-12-07 | 西安安聚德纳米科技有限公司 | A kind of ultra-wide incidence angle microwave absorbing material and preparation method thereof |
-
2018
- 2018-12-14 CN CN201811534299.3A patent/CN109788728B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000188513A (en) * | 1998-10-15 | 2000-07-04 | Riken Corp | Composite radio wave absorber and its working method |
| CN203795889U (en) * | 2014-03-27 | 2014-08-27 | 上海一航凯迈光机电设备有限公司 | Infrared-microwave composite darkroom |
| CN104735964A (en) * | 2015-02-02 | 2015-06-24 | 邓秀梅 | Microwave-absorbing material for microwave chamber and printing production method thereof |
| CN106903931A (en) * | 2017-02-24 | 2017-06-30 | 浙江大胜达包装股份有限公司 | Steam ladder utilizes system on corrugated paper production line |
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