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WO2025245910A1 - High flame-retardant polymer foam microwave-absorbing material containing expanded graphite and preparation method therefor - Google Patents

High flame-retardant polymer foam microwave-absorbing material containing expanded graphite and preparation method therefor

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Publication number
WO2025245910A1
WO2025245910A1 PCT/CN2024/097222 CN2024097222W WO2025245910A1 WO 2025245910 A1 WO2025245910 A1 WO 2025245910A1 CN 2024097222 W CN2024097222 W CN 2024097222W WO 2025245910 A1 WO2025245910 A1 WO 2025245910A1
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Prior art keywords
parts
foam particles
expanded graphite
polymer foam
absorbing material
Prior art date
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Pending
Application number
PCT/CN2024/097222
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French (fr)
Chinese (zh)
Inventor
王军耀
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Wuxi Fregep Absorbing Material Technology Co Ltd
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Wuxi Fregep Absorbing Material Technology Co Ltd
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Publication of WO2025245910A1 publication Critical patent/WO2025245910A1/en
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/04—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent
    • C08J9/12—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent by a physical blowing agent
    • C08J9/122—Hydrogen, oxygen, CO2, nitrogen or noble gases
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/0061—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof characterized by the use of several polymeric components
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/0066—Use of inorganic compounding ingredients
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/009—Use of pretreated compounding ingredients
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/0095—Mixtures of at least two compounding ingredients belonging to different one-dot groups
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/16—Making expandable particles
    • C08J9/18—Making expandable particles by impregnating polymer particles with the blowing agent
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/22—After-treatment of expandable particles; Forming foamed products
    • C08J9/224—Surface treatment
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/22—After-treatment of expandable particles; Forming foamed products
    • C08J9/228—Forming foamed products
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K9/00—Screening of apparatus or components against electric or magnetic fields
    • H05K9/0073—Shielding materials
    • H05K9/0081—Electromagnetic shielding materials, e.g. EMI, RFI shielding
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2203/00—Foams characterized by the expanding agent
    • C08J2203/06—CO2, N2 or noble gases
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2323/00—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers
    • C08J2323/02—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers not modified by chemical after treatment
    • C08J2323/10—Homopolymers or copolymers of propene
    • C08J2323/12—Polypropene
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2423/00—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers
    • C08J2423/02—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers not modified by chemical after treatment
    • C08J2423/04—Homopolymers or copolymers of ethene
    • C08J2423/06—Polyethene
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2431/00—Characterised by the use of copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an acyloxy radical of a saturated carboxylic acid, or carbonic acid, or of a haloformic acid
    • C08J2431/02—Characterised by the use of omopolymers or copolymers of esters of monocarboxylic acids
    • C08J2431/04—Homopolymers or copolymers of vinyl acetate
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/02—Elements
    • C08K2003/026—Phosphorus
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/38—Boron-containing compounds
    • C08K2003/387—Borates
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/02—Elements
    • C08K3/04—Carbon
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K7/00—Use of ingredients characterised by shape
    • C08K7/22—Expanded, porous or hollow particles
    • C08K7/24—Expanded, porous or hollow particles inorganic
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K9/00—Use of pretreated ingredients
    • C08K9/10—Encapsulated ingredients

Definitions

  • This invention relates to the field of flame retardant technology for polymer foam microwave absorbing materials with improved oxygen index, and to a polypropylene foam and polyethylene foam microwave absorbing material that meets the oxygen index requirement of greater than 28, and more particularly, a polypropylene foam that meets the oxygen index requirement of greater than 32 and meets the first, second, and third indicators of the NRL Report 8093 standard, as well as the preparation method thereof.
  • the oxygen index of the absorbing material in the electromagnetic anechoic chamber must be greater than 28.
  • customers require the oxygen index to be greater than 32.
  • the US Navy standard NRL Report 8093 requires the absorbing material for electromagnetic anechoic chambers to meet the requirements of items 1, 2, and 3 of this standard.
  • Patent number 201710970210.7 entitled “A Method for Preparing Highly Conductive and Highly Flame-Retardant Polypropylene Foamed Beads,” states that in the examples, a board with a resistance of 800-1350 ohms can achieve an oxygen index of 28. Increasing the pressing density of the prepared board samples can slightly improve the oxygen index, but if a pyramidal absorbing material is to be produced, the oxygen index cannot reach 28. It is even less likely that the oxygen index value will reach a value greater than 32. In the embodiment of patent 201710970210.7, the flat plate absorbing material has a certain absorption effect at a specific frequency of 200M-1.2G.
  • the impedance matching design of the absorbing material to meet the condition of -28dB absorption rate at 200M in the patent embodiment of 201710970210.7, at least a 500-700mm high pyramidal absorbing material is required, or a soft magnetic ferrite sheet absorbing material with an absorption rate of only 200M-1.2G. The top few frequency points of the resonance peak on the curve can be reached.
  • the thickness of the plate material in the embodiment 201710970210.7 is not described, no single-layer thickness of the resistive loss type plate material can meet the absorption rate of 28 at 200M and 69 at 400M. The same is true for other embodiments.
  • this patented method can only be applied to specific frequencies and cannot meet the requirements of wide-band absorption rate and flame retardancy for use in electromagnetic anechoic chamber pyramidal absorbing materials.
  • the absorption rate of the single-layer plate absorbing material at 200M is ⁇ 37.
  • no single-layer resistive loss type absorbing material plate material of any thickness can achieve such indicators. Therefore, this patented method can only be applied to specific frequencies. If pyramidal absorbing materials are to be produced, the oxygen index cannot reach 28, let alone greater than 32. Therefore, this method cannot meet the requirements of wide-band absorption rate and flame retardancy for use in electromagnetic anechoic chamber pyramidal absorbing materials.
  • Foamed polypropylene or polyethylene foam microwave absorbing materials are made by mixing conductive agents, flame retardants, and nucleating agents.
  • conductive agents include conductive agents, flame retardants, and nucleating agents.
  • a relatively large amount of conductive agent needs to be added. If the goal is to produce a material that can still be molded by a foam molding machine after foaming, then the proportion of flame retardant that can be added is relatively small. Therefore, the oxygen index of the final polypropylene or polyethylene foam microwave absorbing material is difficult to exceed 28.
  • the purpose of this invention is to overcome and supplement the shortcomings of the existing technology, and to provide a high flame-retardant polymer foam absorbing material containing expanded graphite and its preparation method. Due to the property that expanded graphite expands several times when heated, it isolates oxygen after expansion, making it an excellent flame-retardant material. However, the particles of expanded graphite are generally relatively large and cannot be melted into polymers and then foamed like other powder materials. Therefore, highly filled expanded graphite is coated onto the surface of polypropylene or polyethylene foam particles in the form of an adhesive.
  • the prepared conductive polymer foam particles are pretreated with an adhesion promoter and then mixed with expanded graphite-containing composite resin foam particles to prepare a polymer foam absorbing material for electromagnetic anechoic chambers.
  • the material requires an oxygen index greater than 28, especially an oxygen index greater than 32, and meets the 1st, 2nd, and 3rd indicators of the NRL Report 8093 standard.
  • a highly flame-retardant wave-absorbing material containing expanded graphite polymer foam wherein, by volume, it comprises 0-90 parts of conductive polymer foam particles and 10-100 parts of expanded graphite composite resin foam particles.
  • the high flame-retardant expanded graphite polymer foam absorbing material comprises, by weight, 30-95 parts of conductive polymer foam particles and 5-70 parts of coating material, wherein the coating material comprises 5-50 parts of adhesive, 1-30 parts of conductive agent, 0-20 parts of first flame retardant, 20-95 parts of expanded graphite, and 13-300 parts of solvent.
  • the high flame-retardant expanded graphite polymer foam absorbing material comprises: the conductive polymer foam particles selected from polypropylene foam particles and polyethylene foam particles, wherein each polypropylene foam particle or polyethylene foam particle includes at least one polypropylene resin or polyethylene resin, and each polypropylene resin or polyethylene resin comprises the following components by weight: 45-95 parts of polypropylene or polyethylene, 5-35 parts of conductive agent, 1-10 parts of dispersant, 1-20 parts of first flame retardant, and 0.1-1 parts of nucleating agent.
  • the conductive agent is selected from one or more of carbon black, graphite, graphene, carbon nanotubes or metal powder;
  • the first flame retardant is selected from one or more of coated red phosphorus, ammonium polyphosphate, aluminum dihydrogen phosphate, pentaerythritol phosphate, and brominated polystyrene.
  • the dispersant is selected from one or two of PE wax and triphenyl phosphate.
  • the adhesive is selected from one or more of phenolic resin, acrylic resin, ethylene-acrylic acid copolymer, polyvinyl acetate, polyurethane adhesive and silicone resin.
  • the outer surface of the conductive polymer foam particles is further coated with an adhesion promoter, and the mass ratio of the conductive polymer foam particles to the adhesion promoter is 80-99:1-20.
  • the adhesion promoter is a chlorinated polypropylene solution.
  • a method for preparing a highly flame-retardant expanded graphite polymer foam microwave absorbing material comprising the following steps:
  • Step S1 By weight, 45-95 parts of polypropylene or polyethylene, 5-35 parts of conductive agent, 1-10 parts of dispersant, and 1-20 parts of first flame retardant are mixed evenly to obtain a first mixture. Then, the first mixture is mixed in an internal mixer and extruded through a twin-screw extruder to obtain at least 0.3-2 mg of polypropylene resin or polyethylene resin.
  • Step S2 Add at least one polypropylene resin or polyethylene resin from step S1 to a high-pressure reactor, and add water and surfactant to the high-pressure reactor. Then start stirring, heat and introduce nitrogen or carbon dioxide. Continue heating until the melting point of the polypropylene resin or polyethylene resin is reached, and release the material to foam and obtain polypropylene foam particles or polyethylene foam particles, thus obtaining conductive polymer foam particles.
  • Step S3 By weight, add 5-50 parts of adhesive, 1-30 parts of conductive agent, 1-30 parts of first flame retardant, 20-95 parts of expanded graphite and 13-300 parts of solvent to a disperser and disperse evenly to obtain a coating.
  • Step S4 By weight, add 30-95 parts of conductive polymer foam particles from step S3 to a mixing tank, then add 5-70 parts of coating material from S4 and stir to obtain a second mixture. Add the second mixture to a drying device to dry and sieve to obtain foam particles containing expanded graphite composite resin.
  • Step S5 By volume, 0-90 parts of conductive polymer foam particles and 10-100 parts of expanded graphite composite resin foam particles are mixed to obtain a third mixture, and then the third mixture is molded to obtain a microwave absorbing material.
  • a method for preparing a highly flame-retardant expanded graphite polymer foam microwave absorbing material comprising the following steps by weight:
  • Step S1 By weight, 45-95 parts of polypropylene or polyethylene, 5-35 parts of conductive agent, 1-10 parts of dispersant, and 1-20 parts of first flame retardant are mixed evenly to obtain a first mixture. Then, the first mixture is mixed in an internal mixer and extruded through a twin-screw extruder to obtain at least 0.3-2 mg of polypropylene resin or polyethylene resin.
  • Step S2 Add at least one polypropylene resin or polyethylene resin from step S1 to a high-pressure reactor, and add water and surfactant to the high-pressure reactor. Then start stirring, heat and introduce nitrogen or carbon dioxide. Continue heating until the melting point of polypropylene resin or polyethylene resin is reached, and release the material to foam and obtain polypropylene foam particles and polyethylene foam particles, thus obtaining conductive polymer foam particles.
  • Step S3 By weight, mix 80-99 parts of conductive polymer foam particles from step S2 with 1-20 parts of adhesion promoter and add them to an air-drying device to dry, thereby obtaining composite foam particles.
  • Step S4 By weight, add 5-50 parts of adhesive, 1-30 parts of conductive agent, 1-30 parts of first flame retardant, 20-95 parts of expanded graphite and 13-300 parts of solvent to a disperser and disperse evenly to obtain a coating.
  • Step S5 By weight, add 30-95 parts of the composite foam particles from step S3 to a mixing tank, then add 5-70 parts of the coating material from S4 and stir to obtain a second mixture. Add the second mixture to a drying equipment to dry, and sieve to obtain foam particles containing expanded graphite composite resin.
  • Step S6 Mix 0-90 parts of composite foam particles and 10-100 parts of expanded graphite composite resin foam particles by volume to obtain a third mixture, and then mold the third mixture to obtain a microwave absorbing material.
  • This invention utilizes the synergistic effect of red phosphorus and expanded graphite as a flame retardant.
  • Red phosphorus burns upon heating to produce phosphorus pentoxide.
  • the expanded graphite adsorbs the sulfuric acid compounds in the graphite intercalation and begins to decompose.
  • the expanded graphite flakes expand vertically, expanding to hundreds of times their original size to form graphite worms.
  • the sulfuric acid compounds decompose to produce SO2 , CO2 , and water.
  • the combustion of polypropylene or polyethylene produces CO2 and water.
  • the phosphorus pentoxide generated by the combustion of red phosphorus captures the decomposition reaction of sulfuric acid compounds in the expanded graphite intercalation and the water vapor molecules generated by the combustion of the polymer, forming phosphate hydrate H3PO4 .
  • the expanded graphite expands to form graphite worms that interweave and support the burning polymer surface.
  • the polymer surface is also catalyzed by the acid formed by the combustion of red phosphorus to form carbon, and the inorganic powders such as carbon black and graphite in the polymer are also hydrated into phosphate hydrate H3PO4 by the combustion of red phosphorus .
  • the thick, oily substance binds these substances together to form a three-dimensional and dense oxygen-barrier structure. Due to the interlacing support of expanded graphite worms on the polymer surface and the phosphate crystal hydrate H3PO4 formed by the combustion of red phosphorus, a three -dimensional oxygen-barrier structure is formed. This synergistic effect can effectively prevent the entry of oxygen, thereby improving the flame retardant effect of the microwave absorbing material.
  • the polymer foam microwave absorbing material for electromagnetic anechoic chambers requires an oxygen index greater than 28.
  • the microwave absorbing material of this invention can actually achieve an oxygen index greater than 32, meeting the 1st, 2nd, and 3rd indicators of the NRLReport8093 standard.
  • the present invention uses a pressure mixer to mix the conductive agent and various powder additives and then granulate them. Due to the accurate formula ratio, the stability and batch consistency of the dielectric constant and loss tangent of the electromagnetic parameters of the absorbing material can be ensured.
  • the first flame retardant in the coating of the present invention is 0-20 parts. Since expanded graphite is conductive, it is necessary to adjust the electromagnetic parameters of each layer of material when producing multi-layer composite microwave absorbing materials. When producing high-frequency, ultra-high-frequency or terahertz microwave absorbing materials, it is necessary to adjust the electromagnetic parameters and reduce the proportion of expanded graphite.
  • the non-conductive first flame retardant is used to replace part of the expanded graphite to adjust the electromagnetic parameters. Although the flame retardant effect is not as good as that of high-filled expanded graphite, it can still meet the flame retardant requirement of the basic flame retardant index of microwave absorbing materials being greater than 28.
  • the high flame-retardant polymer foam absorbing material containing expanded graphite of the present invention can replace the traditional polyurethane sponge absorbing material. After the electromagnetic wave anechoic chamber is dismantled, the polymer foam absorbing material can be recycled, melted and reprocessed into other plastic products.
  • the traditional polyurethane sponge absorbing material can only be incinerated after it is dismantled and scrapped.
  • the polymer foam absorbing material of the present invention can reduce environmental pollution. Its low water absorption rate and high oxygen index characteristics can also be applied in outdoor and military camouflage fields, and its application prospects are relatively broad.
  • Figure 1 shows the SEM images of the expanded graphite composite resin foam particles prepared in Examples 1-9.
  • Figure 2 is a SEM image of the expanded graphite composite resin foam particles prepared in Examples 1-9 after being cut open.
  • Figure 3 is a schematic diagram of the structure of the 500 high-absorbing cone microwave absorbing material prepared in Examples 1-9 and Comparative Examples 1-2 of the present invention.
  • a method for preparing a highly flame-retardant microwave absorbing material containing expanded graphite polymer foam includes the following steps:
  • Step S1 By weight, 62.9 parts of polypropylene, 25 parts of conductive carbon black, 2 parts of PE wax, 0.1 parts of zinc borate, and 8 parts of coated red phosphorus are mixed evenly to obtain a first mixture. Then, the first mixture is mixed in an internal mixer and extruded through a twin-screw extruder.
  • the twin-screw extruder has eleven stages, and the extrusion temperatures are as follows: stage 1 140°C, stage 2 150°C, stage 3 165°C, stage 4 175°C, stage 5 180°C, stage 6 185°C, stage 7 192°C, stage 8 185°C, stage 9 192°C, stage 10 185°C, stage 11 192°C, and the die is 210°C, to obtain 0.3-2 mg of polypropylene resin.
  • Step S2 Add the polypropylene resin obtained in step S1 to a high-pressure reactor. Add water with a weight of 2 times that of the added polypropylene resin and sodium dodecylbenzenesulfonate with a weight of 3% of the added water to the high-pressure reactor. Start stirring, heat and introduce carbon dioxide. The pressure is 3.5 MPa and the reactor temperature is 140°C. Release the material, foam, wash and dry to obtain polypropylene foam particles with a density of 45 kg/ m3 , and obtain conductive polymer foam particles.
  • Step S3 By weight, add 28 parts of polyvinyl acetate, 5 parts of conductive carbon black, 67 parts of 80-mesh expanded graphite and 60 parts of ethanol to a disperser and disperse evenly.
  • the disperser speed is 1500 rpm and the dispersion time is 30 minutes to obtain the coating.
  • Step S4 By weight, add 20kg of conductive polymer foam particles obtained in step S3 to a mixing tank, then add 30kg of coating material and stir to obtain a second mixture.
  • the stirring speed is 80 rpm.
  • the second mixture is then added to a drying device for drying.
  • the main shaft crushing motor is set to 30 rpm. The drying and crushing process takes 20 minutes.
  • the mixture is then sieved to obtain foam particles containing expanded graphite composite resin.
  • Step S5 By volume, the 50L conductive polymer foam particles and 50L expanded graphite composite resin foam particles obtained in step S3 are mixed to obtain a third mixture, and then the third mixture is molded to obtain a 500 high-angle pyramidal microwave absorbing material.
  • a method for preparing a highly flame-retardant microwave absorbing material containing expanded graphite polymer foam includes the following steps:
  • Step S1 By weight, 62.9 parts of polypropylene, 25 parts of conductive carbon black, 2 parts of PE wax, 0.1 parts of zinc borate, and 8 parts of coated red phosphorus are mixed evenly to obtain a first mixture. Then, the first mixture is mixed in an internal mixer and extruded through a twin-screw extruder.
  • the twin-screw extruder has eleven stages, and the extrusion temperatures are as follows: stage 1 140°C, stage 2 150°C, stage 3 165°C, stage 4 175°C, stage 5 180°C, stage 6 185°C, stage 7 192°C, stage 8 185°C, stage 9 192°C, stage 10 185°C, stage 11 192°C, and the die is 210°C, to obtain 0.3-2 mg of polypropylene resin.
  • Step S2 Add the polypropylene resin obtained in step S1 to a high-pressure reactor. Add water with a weight of 2 times that of the added polypropylene resin and sodium dodecylbenzenesulfonate with a weight of 3% of the added water to the high-pressure reactor. Start stirring, heat and introduce carbon dioxide. The pressure is 3.5 MPa and the reactor temperature is 140°C. Release the material, foam, wash and dry to obtain polypropylene foam particles with a density of 45 kg/ m3 , and obtain conductive polymer foam particles.
  • Step S3 By weight, add 28 parts of polyvinyl acetate, 5 parts of conductive carbon black, 67 parts of 80-mesh expanded graphite and 60 parts of ethanol to a disperser and disperse evenly.
  • the disperser speed is 1500 rpm and the dispersion time is 30 minutes to obtain the coating.
  • Step S4 By weight, add 20 kg of conductive polymer foam particles obtained in step S3 to the mixer. In the mixing tank, 30 kg of coating material was added and stirred to obtain a second mixture. The stirring speed was 80 rpm. The second mixture was then added to the air drying equipment for drying. The main shaft crushing motor was set to 30 rpm. The drying and crushing were carried out for 20 minutes. The mixture was then sieved to obtain foam particles containing expanded graphite composite resin.
  • Step S5 By volume, the 60L conductive polymer foam particles and 40L expanded graphite composite resin foam particles obtained in step S3 are mixed to obtain a third mixture, and then the third mixture is molded to obtain a 500 high-angle pyramidal microwave absorbing material.
  • a method for preparing a highly flame-retardant microwave absorbing material containing expanded graphite polymer foam includes the following steps:
  • Step S1 By weight, 62.9 parts of polypropylene, 25 parts of conductive carbon black, 2 parts of PE wax, 0.1 parts of zinc borate, and 8 parts of coated red phosphorus are mixed evenly to obtain a first mixture. Then, the first mixture is mixed in an internal mixer and extruded through a twin-screw extruder.
  • the twin-screw extruder has eleven stages, and the extrusion temperatures are as follows: stage 1 140°C, stage 2 150°C, stage 3 165°C, stage 4 175°C, stage 5 180°C, stage 6 185°C, stage 7 192°C, stage 8 185°C, stage 9 192°C, stage 10 185°C, stage 11 192°C, and the die is 210°C, to obtain 0.3-2 mg of polypropylene resin.
  • Step S2 Add the polypropylene resin obtained in step S1 to a high-pressure reactor. Add water with a weight of 2 times that of the added polypropylene resin and sodium dodecylbenzenesulfonate with a weight of 3% of the added water to the high-pressure reactor. Start stirring, heat and introduce carbon dioxide. The pressure is 3.5 MPa and the reactor temperature is 140°C. Release the material, foam, wash and dry to obtain polypropylene foam particles with a density of 45 kg/ m3 , and obtain conductive polymer foam particles.
  • Step S3 By weight, add 28 parts of polyvinyl acetate, 5 parts of conductive carbon black, 67 parts of 80-mesh expanded graphite and 60 parts of ethanol to a disperser and disperse evenly.
  • the disperser speed is 1500 rpm and the dispersion time is 30 minutes to obtain the coating.
  • Step S4 By weight, add 20kg of conductive polymer foam particles obtained in step S3 to a mixing tank, then add 30kg of coating material and stir to obtain a second mixture.
  • the stirring speed is 80 rpm.
  • the second mixture is then added to a drying device for drying.
  • the main shaft crushing motor is set to 30 rpm. The drying and crushing process takes 20 minutes.
  • the mixture is then sieved to obtain foam particles containing expanded graphite composite resin.
  • Step S5 By volume, mix the 70L conductive polymer foam particles and 30L expanded graphite composite resin foam particles obtained in step S3 to obtain a third mixture, and then mold the third mixture to obtain a 500 high-angle pyramidal microwave absorbing material.
  • a method for preparing a highly flame-retardant microwave absorbing material containing expanded graphite polymer foam includes the following steps:
  • Step S1 By weight, 62.9 parts of polypropylene, 25 parts of conductive carbon black, 2 parts of PE wax, 0.1 parts of zinc borate, and 8 parts of coated red phosphorus are mixed evenly to obtain a first mixture. Then, the first mixture is mixed in an internal mixer and extruded through a twin-screw extruder.
  • the twin-screw extruder has eleven stages, and the extrusion temperatures are as follows: stage 1 140°C, stage 2 150°C, stage 3 165°C, stage 4 175°C, stage 5 180°C, stage 6 185°C, stage 7 192°C, stage 8 185°C, stage 9 192°C, stage 10 185°C, stage 11 192°C, and the die is 210°C, to obtain 0.3-2 mg of polypropylene resin.
  • Step S2 Add the polypropylene resin obtained in step S1 to a high-pressure reactor, and add water equal to twice the weight of the added polypropylene resin and sodium dodecylbenzenesulfonate at 3% of the weight of the added water to the high-pressure reactor. Stirring was started, heating was carried out and carbon dioxide was introduced. The pressure was 3.5 MPa and the temperature of the reactor was 140°C. The material was released, foamed, washed and dried to obtain polypropylene foam particles with a density of 45 kg/ m3 , thus obtaining conductive polymer foam particles.
  • Step S3 Add 28 parts of polyvinyl acetate, 5 parts of conductive carbon black, 67 parts of 80-mesh expanded graphite and 60 parts of ethanol to a disperser and disperse evenly.
  • the disperser speed is 1500 rpm and the dispersion time is 30 minutes to obtain the coating.
  • Step S4 By weight, add 20kg of conductive polymer foam particles obtained in step S3 to a mixing tank, then add 30kg of coating material and stir to obtain a second mixture.
  • the stirring speed is 80 rpm.
  • the second mixture is then added to a drying device for drying.
  • the main shaft crushing motor is set to 30 rpm. The drying and crushing process takes 20 minutes.
  • the mixture is then sieved to obtain foam particles containing expanded graphite composite resin.
  • Step S5 By volume, mix 80L of conductive polymer foam particles and 20L of expanded graphite composite resin foam particles obtained in step S3 to obtain a third mixture, and then mold the third mixture to obtain a 500 high-angle pyramidal microwave absorbing material.
  • a method for preparing a highly flame-retardant microwave absorbing material containing expanded graphite polymer foam includes the following steps:
  • Step S1 By weight, 62.9 parts of polypropylene, 25 parts of conductive carbon black, 2 parts of PE wax, 0.1 parts of zinc borate, and 8 parts of coated red phosphorus are mixed evenly to obtain a first mixture. Then, the first mixture is mixed in an internal mixer and extruded through a twin-screw extruder.
  • the twin-screw extruder has eleven stages, and the extrusion temperatures are as follows: stage 1 140°C, stage 2 150°C, stage 3 165°C, stage 4 175°C, stage 5 180°C, stage 6 185°C, stage 7 192°C, stage 8 185°C, stage 9 192°C, stage 10 185°C, stage 11 192°C, and the die is 210°C, to obtain 0.3-2 mg of polypropylene resin.
  • Step S2 Add the polypropylene resin obtained in step S1 to a high-pressure reactor. Add water with a weight of 2 times that of the added polypropylene resin and sodium dodecylbenzenesulfonate with a weight of 3% of the added water to the high-pressure reactor. Start stirring, heat and introduce carbon dioxide. The pressure is 3.5 MPa and the reactor temperature is 140°C. Release the material, foam, wash and dry to obtain polypropylene foam particles with a density of 45 kg/ m3 , and obtain conductive polymer foam particles.
  • Step S3 By weight, add 28 parts of polyvinyl acetate, 5 parts of conductive carbon black, 67 parts of 80-mesh expanded graphite and 60 parts of ethanol to a disperser and disperse evenly.
  • the disperser speed is 1500 rpm and the dispersion time is 30 minutes to obtain the coating.
  • Step S4 By weight, add 20kg of conductive polymer foam particles obtained in step S3 to a mixing tank, then add 30kg of coating material and stir to obtain a second mixture.
  • the stirring speed is 80 rpm.
  • the second mixture is then added to a drying device for drying.
  • the main shaft crushing motor is set to 30 rpm. The drying and crushing process takes 20 minutes.
  • the mixture is then sieved to obtain foam particles containing expanded graphite composite resin.
  • Step S5 By volume, mix the 90L conductive polymer foam particles and 10L expanded graphite composite resin foam particles obtained in step S3 to obtain a third mixture, and then mold the third mixture to obtain a 500 high-angle pyramidal microwave absorbing material.
  • a method for preparing a highly flame-retardant microwave absorbing material containing expanded graphite polymer foam includes the following steps:
  • Step S1 By weight, combine 62.9 parts polypropylene, 25 parts conductive carbon black, 2 parts PE wax, and 0.1 parts... One part zinc borate and eight parts coated red phosphorus were mixed evenly to obtain a first mixture. The first mixture was then mixed in an internal mixer and extruded through a twin-screw extruder.
  • the twin-screw extruder has eleven sections, and the extrusion temperatures are as follows: section 1 140°, section 2 150°, section 3 165°, section 4 175°, section 5 180°, section 6 185°, section 7 192°, section 8 185°, section 9 192°, section 10 185°, section 11 192°, and the die is 210°, to obtain 0.3-2 mg of polypropylene resin.
  • Step S2 Add the polypropylene resin obtained in step S1 to a high-pressure reactor. Add water with a weight of 2 times that of the added polypropylene resin and sodium dodecylbenzenesulfonate with a weight of 3% of the added water to the high-pressure reactor. Start stirring, heat and introduce carbon dioxide. The pressure is 3.5 MPa and the reactor temperature is 140°C. Release the material, foam, wash and dry to obtain polypropylene foam particles with a density of 45 kg/ m3 , and obtain conductive polymer foam particles.
  • Step S3 By weight, add 28 parts of polyvinyl acetate, 5 parts of conductive carbon black, 67 parts of 80-mesh expanded graphite and 60 parts of ethanol to a disperser and disperse evenly.
  • the disperser speed is 1500 rpm and the dispersion time is 30 minutes to obtain the coating.
  • Step S4 By weight, add 20kg of conductive polymer foam particles obtained in step S3 to a mixing tank, then add 30kg of coating material and stir to obtain a second mixture.
  • the stirring speed is 80 rpm.
  • the second mixture is then added to a drying device for drying.
  • the main shaft crushing motor is set to 30 rpm. The drying and crushing process takes 20 minutes.
  • the mixture is then sieved to obtain foam particles containing expanded graphite composite resin.
  • Step S5 By volume, the 40L conductive polymer foam particles and 60L expanded graphite composite resin foam particles obtained in step S3 are mixed to obtain a third mixture, and then the third mixture is molded to obtain a 500 high-angle pyramidal microwave absorbing material.
  • a method for preparing a highly flame-retardant microwave absorbing material containing expanded graphite polymer foam includes the following steps:
  • Step S1 By weight, 62.9 parts of polypropylene, 25 parts of conductive carbon black, 2 parts of PE wax, 0.1 parts of zinc borate, and 8 parts of coated red phosphorus are mixed evenly to obtain a first mixture. Then, the first mixture is mixed in an internal mixer and extruded through a twin-screw extruder.
  • the twin-screw extruder has eleven stages, and the extrusion temperatures are as follows: stage 1 140°C, stage 2 150°C, stage 3 165°C, stage 4 175°C, stage 5 180°C, stage 6 185°C, stage 7 192°C, stage 8 185°C, stage 9 192°C, stage 10 185°C, stage 11 192°C, and the die is 210°C, to obtain 0.3-2 mg of polypropylene resin.
  • Step S2 Add the polypropylene resin obtained in step S1 to a high-pressure reactor. Add water with a weight of 2 times that of the added polypropylene resin and sodium dodecylbenzenesulfonate with a weight of 3% of the added water to the high-pressure reactor. Start stirring, heat and introduce carbon dioxide. The pressure is 3.5 MPa and the reactor temperature is 140°C. Release the material, foam, wash and dry to obtain polypropylene foam particles with a density of 45 kg/ m3 , and obtain conductive polymer foam particles.
  • Step S3 By weight, add 28 parts of polyvinyl acetate, 5 parts of conductive carbon black, 67 parts of 80-mesh expanded graphite and 60 parts of ethanol to a disperser and disperse evenly.
  • the disperser speed is 1500 rpm and the dispersion time is 30 minutes to obtain the coating.
  • Step S4 By weight, add 20 kg of conductive polymer foam particles obtained in step S3 to a mixing tank, then add 30 kg of coating material and stir to obtain a second mixture at a stirring speed of 80 rpm. The second mixture is then added to a drying device for drying, with the main shaft crushing motor set to 30 rpm. Crumble for 20 minutes and sieve to obtain foam particles containing expanded graphite composite resin;
  • Step S5 The 100L expanded graphite composite resin foam particles obtained in step S4 are molded into a 500 high-angle cone microwave absorbing material.
  • a method for preparing a highly flame-retardant microwave absorbing material containing expanded graphite polymer foam includes the following steps:
  • Step S1 By weight, 62.9 parts of polypropylene, 25 parts of conductive carbon black, 2 parts of PE wax, 0.1 parts of zinc borate, and 8 parts of ammonium polyphosphate are mixed evenly to obtain a first mixture. Then, the first mixture is mixed in an internal mixer and extruded through a twin-screw extruder.
  • the twin-screw extruder has eleven stages, and the extrusion temperatures are as follows: stage 1 140°C, stage 2 150°C, stage 3 165°C, stage 4 175°C, stage 5 180°C, stage 6 185°C, stage 7 192°C, stage 8 185°C, stage 9 192°C, stage 10 185°C, stage 11 192°C, and the die is 210°C, to obtain 0.3-2 mg of polypropylene resin.
  • Step S2 Add the polypropylene resin obtained in step S1 to a high-pressure reactor. Add water with a weight of 2 times that of the added polypropylene resin and sodium dodecylbenzenesulfonate with a weight of 3% of the added water to the high-pressure reactor. Start stirring, heat and introduce carbon dioxide. The pressure is 3.5 MPa and the reactor temperature is 140°C. Release the material, foam, wash and dry to obtain polypropylene foam particles with a density of 45 kg/ m3 , and obtain conductive polymer foam particles.
  • Step S3 By weight, add 28 parts of polyvinyl acetate, 5 parts of conductive carbon black, 67 parts of 80-mesh expanded graphite and 60 parts of ethanol to a disperser and disperse evenly.
  • the disperser speed is 1500 rpm and the dispersion time is 30 minutes to obtain the coating.
  • Step S4 By weight, add 20kg of conductive polymer foam particles obtained in step S3 to a mixing tank, then add 30kg of coating material and stir to obtain a second mixture.
  • the stirring speed is 80 rpm.
  • the second mixture is then added to a drying device for drying.
  • the main shaft crushing motor is set to 30 rpm. The drying and crushing process takes 20 minutes.
  • the mixture is then sieved to obtain foam particles containing expanded graphite composite resin.
  • Step S5 By volume, the 50L conductive polymer foam particles and 50L expanded graphite composite resin foam particles obtained in step S3 are mixed to obtain a third mixture, and then the third mixture is molded to obtain a 500 high-angle pyramidal microwave absorbing material.
  • a method for preparing a highly flame-retardant microwave absorbing material containing expanded graphite polymer foam includes the following steps:
  • Step S1 By weight, 62.9 parts of polypropylene, 25 parts of conductive carbon black, 2 parts of PE wax, 0.1 parts of zinc borate, and 8 parts of coated red phosphorus are mixed evenly to obtain a first mixture. Then, the first mixture is mixed in an internal mixer and extruded through a twin-screw extruder.
  • the twin-screw extruder has eleven stages, and the extrusion temperatures are as follows: stage 1 140°C, stage 2 150°C, stage 3 165°C, stage 4 175°C, stage 5 180°C, stage 6 185°C, stage 7 192°C, stage 8 185°C, stage 9 192°C, stage 10 185°C, stage 11 192°C, and the die is 210°C, to obtain 0.3-2 mg of polypropylene resin.
  • Step S2 Add the polypropylene resin obtained in step S1 to a high-pressure reactor. Add water with a weight of 2 times that of the added polypropylene resin and sodium dodecylbenzenesulfonate with a weight of 3% of the added water to the high-pressure reactor. Start stirring, heat and introduce carbon dioxide. The pressure is 3.5 MPa and the reactor temperature is 140°C. Release the material, foam, wash and dry to obtain polypropylene foam particles with a density of 45 kg/ m3 , and obtain conductive polymer foam particles.
  • Step S3 By weight, mix 99 parts of conductive polymer foam particles from step S2 with 1 part of adhesion promoter and add them to a drying equipment to dry, thereby obtaining composite foam particles.
  • Step S4 By weight, add 28 parts of polyvinyl acetate, 5 parts of conductive carbon black, 67 parts of 80-mesh expanded graphite and 60 parts of ethanol to a disperser and disperse evenly.
  • the disperser speed is 1500 rpm and the dispersion time is 30 minutes to obtain the coating.
  • Step S5 By weight, add 20kg of composite foam particles obtained in step S3 to a mixing tank, then add 30kg of coating material and stir to obtain a second mixture.
  • the stirring speed is 80 rpm.
  • the second mixture is then added to a drying device for drying.
  • the main shaft crushing motor is set to 30 rpm. The drying and crushing process takes 20 minutes.
  • the mixture is then sieved to obtain foam particles containing expanded graphite composite resin.
  • Step S6 The 100L expanded graphite composite resin foam particles obtained in step S5 are molded into a 500 high-angle cone microwave absorbing material.
  • a method for preparing a highly flame-retardant microwave absorbing material containing expanded graphite polymer foam includes the following steps:
  • Step S1 By weight, 64.9 parts of polypropylene, 25 parts of conductive carbon black, 2 parts of PE wax, 0.1 parts of zinc borate, and 8 parts of coated red phosphorus are mixed evenly to obtain a first mixture. Then, the first mixture is mixed in an internal mixer and extruded through a twin-screw extruder.
  • the twin-screw extruder has eleven stages, and the extrusion temperatures are as follows: stage 1 140°C, stage 2 150°C, stage 3 165°C, stage 4 175°C, stage 5 180°C, stage 6 185°C, stage 7 192°C, stage 8 185°C, stage 9 192°C, stage 10 185°C, stage 11 192°C, and die 210°C, to obtain 0.3-2 mg of polypropylene resin.
  • Step S2 Add polypropylene resin to a high-pressure reactor, add water equal to twice the weight of the added polypropylene resin and sodium dodecylbenzenesulfonate equal to 3% of the weight of the added water to the high-pressure reactor, start stirring, heat and introduce carbon dioxide, the pressure is 3.5 MPa, the reactor temperature is 140°C, release the material to foam, wash and dry to obtain conductive polypropylene foam particles with a density of 45 kg/ m3 .
  • Step S3 100L of conductive polypropylene foam particles are molded to obtain 500 high-absorption cone microwave absorbing material.
  • a method for preparing a highly flame-retardant microwave absorbing material containing expanded graphite polymer foam includes the following steps:
  • Step S1 By weight, 70.9 parts polypropylene, 25 parts conductive carbon black, 2 parts PE wax, and 0.1 parts zinc borate are mixed evenly to obtain a first mixture.
  • the first mixture is then mixed in an internal mixer and extruded through a twin-screw extruder.
  • the twin-screw extruder has eleven stages, and the extrusion temperatures are as follows: stage 1 140°C, stage 2 150°C, stage 3 165°C, stage 4 175°C, stage 5 180°C, stage 6 185°C, stage 7 192°C, stage 8 185°C, stage 9 192°C, stage 10 185°C, stage 11 192°C, and die 210°C, to obtain 0.3-2 mg of polypropylene resin.
  • Step S2 Add the polypropylene resin obtained in step S1 to a high-pressure reactor. Add water with a weight of 2 times that of the added polypropylene resin and sodium dodecylbenzenesulfonate with a weight of 3% of the added water to the high-pressure reactor. Start stirring, heat and introduce carbon dioxide. The pressure is 3.5 MPa and the reactor temperature is 140°C. Release the material, foam, wash and dry to obtain polypropylene foam particles with a density of 45 kg/ m3 , and obtain conductive polymer foam particles.
  • Step S3 By weight, add 28 parts polyvinyl acetate, 5 parts conductive carbon black, 67 parts 80-mesh expanded graphite, and 60 parts ethanol to a disperser and disperse evenly at a speed of 1500 rpm for 30 minutes. The clock was coated with a coating.
  • Step S4 By weight, add 20kg of conductive polymer foam particles obtained in step S3 to a mixing tank, then add 30kg of coating material and stir to obtain a second mixture.
  • the stirring speed is 80 rpm.
  • the second mixture is then added to a drying device for drying.
  • the main shaft crushing motor is set to 30 rpm. The drying and crushing process takes 20 minutes.
  • the mixture is then sieved to obtain foam particles containing expanded graphite composite resin.
  • Step S5 By volume, the 50L conductive polymer foam particles and 50L expanded graphite composite resin foam particles obtained in step S3 are mixed to obtain a third mixture, and then the third mixture is molded to obtain a 500 high-angle pyramidal microwave absorbing material.
  • Comparative Example 1 without the addition of expanded graphite and only with the addition of 8% red phosphorus flame retardant, had an oxygen index of 25. Increasing the proportion of red phosphorus flame retardant further did not significantly improve the oxygen index. Adding more than 15% red phosphorus had the opposite effect, as red phosphorus is a highly flammable material and poses a safety hazard to the extrusion granulation process and equipment. Comparative Example 2, without the addition of red phosphorus flame retardant, produced foamed polypropylene granules. Testing revealed that the oxygen index without red phosphorus flame retardant was only 24.
  • Example 1 compares polypropylene resin foam particles containing red phosphorus flame retardant and composite resin foam particles containing expanded graphite in a 50:50 ratio. A comprehensive performance evaluation was conducted, and the oxygen index reached 32.5. However, due to the presence of expanded graphite... The surface of the expanded graphite composite resin foam particles is coated with a layer of coating. Due to the weak compatibility and adhesion between the coating and the polypropylene foam, it is equivalent to the expanded graphite composite resin foam particles being sandwiched between the conductive polymer foam particles. Due to excessive mixing, the conductive polymer foam particles cannot be continuously fused. Therefore, physical property tests show that its elongation at break is 0.5%, as can be seen from other examples later.
  • Example 7 is a microwave absorbing material made solely from expanded graphite composite resin foam particles, with an oxygen index as high as 33.5. Since the adhesion between adhesives is better than the adhesion between adhesives and the surface of polymer resin, Example 7 has better mechanical properties than the mechanical properties of a mixture containing a large proportion of expanded graphite composite resin foam particles.
  • Example 8 uses ammonium polyphosphate (APP) to replace red phosphorus flame retardant. Compared with Example 1, since APP has a lower phosphorus content, it helps to improve the oxygen index to some extent. However, tests show that its effect on improving the oxygen index is not as good as the effect of the combination of expanded graphite and red phosphorus flame retardant.
  • APP ammonium polyphosphate
  • Example 9 involved treating the surface of conductive polymer foam particles with an adhesion promoter and then coating it with a layer of expanded graphite. Tests showed that the mechanical properties were significantly improved compared to the fully coated expanded graphite layer in Example 7.
  • Example 5 By comparing Example 5 with Comparative Example 1, it is found that mixing 20 parts of expanded graphite composite resin foam particles with conductive polymer foam particles can meet the requirement of an oxygen index greater than 28 in the Technical Specification for Electromagnetic Anechoic Chamber Engineering (GB50826-2012). Examples 7 and 9 can even meet the actual use requirements of most customers for an oxygen index greater than 32.
  • FIG. 1 expanded graphite is uniformly attached to the surface of polypropylene foam particles.
  • Figure 2 is a scanning electron microscope image of a cut polypropylene particle. Adding less nucleating agent can increase the pore size of the foam and improve the surface roughness of the foam particles, thus helping to improve adhesion.

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Abstract

The present invention belongs to the technical field of microwave-absorbing materials. Provided are a high flame-retardant polymer foam microwave-absorbing material containing expanded graphite and a preparation method therefor. In terms of parts by volume, the microwave-absorbing material comprises 0-90 parts of conductive polymer foam particles and 10-100 parts of expanded graphite-containing composite resin foam particles; the expanded graphite-containing composite resin foam particles comprise 30-95 parts of conductive polymer foam particles and 5-70 parts of coating. Phosphorus-based flame retardant and expanded graphite in the polymer foam microwave-absorbing material of the present invention have a synergistic effect. The expanded graphite is coated on the surface of the conductive polymer foam particles in the form of an adhesive to obtain the expanded graphite-containing composite resin foam particles. The expanded graphite-containing composite resin foam particles and the conductive polymer foam particles are mixed in a certain ratio, and molded into a microwave-absorbing material, which solves the problem that a polymer foam microwave-absorbing material for electromagnetic wave darkrooms requires an oxygen index greater than 28, especially one that meets an oxygen index greater than 32, and meets indicators 1, 2 and 3 of the NRL Report 8093 standard.

Description

一种高阻燃含膨胀石墨聚合物泡沫吸波材料及其制备方法A high flame-retardant microwave absorbing material containing expanded graphite polymer foam and its preparation method 技术领域Technical Field

本发明涉及提高氧指数聚合物泡沫吸波材料阻燃技术领域，是一种满足氧指数大于28，尤其是一种满足氧指数大于32和满足NRLReport8093标准的1、2、3项指标的聚丙烯泡沫和聚乙烯泡沫吸波材料及其制备方法。This invention relates to the field of flame retardant technology for polymer foam microwave absorbing materials with improved oxygen index, and to a polypropylene foam and polyethylene foam microwave absorbing material that meets the oxygen index requirement of greater than 28, and more particularly, a polypropylene foam that meets the oxygen index requirement of greater than 32 and meets the first, second, and third indicators of the NRL Report 8093 standard, as well as the preparation method thereof.

背景技术Background Technology

在电磁波暗室及军工吸波材料的应用领域，对电磁波暗室阻燃性能及暗室内部环境要求都非常高，目前传统电磁波暗室还是以海绵吸波材料为主，海绵具有高吸水率，使用年限有限，发泡聚苯乙烯材质类吸波材料由于苯乙烯具有致癌性，属于国际癌症研究所(IARC)2B类，对建成的电磁波暗室室内环境不够环保，新型的发泡聚丙烯，发泡聚乙烯吸波材料由于干净，环保，吸水率低受到市场的关注及应用，唯一缺点是阻燃性能不佳。In the application fields of electromagnetic anechoic chambers and military-grade absorbing materials, the requirements for the flame retardant performance and internal environment of electromagnetic anechoic chambers are very high. At present, traditional electromagnetic anechoic chambers are still mainly based on sponge absorbing materials. Sponges have a high water absorption rate and a limited service life. Foamed polystyrene absorbing materials are not environmentally friendly because styrene is carcinogenic and belongs to the International Agency for Research on Cancer (IARC) Group 2B. New foamed polypropylene and foamed polyethylene absorbing materials have attracted market attention and application due to their cleanliness, environmental friendliness and low water absorption rate. The only drawback is their poor flame retardant performance.

依据电磁波暗室工程技术规范(GB50826-2012)中要求，电磁波暗室中吸波材料氧指数必须大于28，还有很多科研院所及大功率测试场合，客户实际使用时更是要求氧指数必须满足大于32；以及美国海军标准NRL Report8093对电磁波暗室吸波材料要求满足此标准的1、2、3项。According to the requirements of the Technical Specification for Electromagnetic Anechoic Chamber Engineering (GB50826-2012), the oxygen index of the absorbing material in the electromagnetic anechoic chamber must be greater than 28. In many research institutes and high-power testing applications, customers require the oxygen index to be greater than 32. Furthermore, the US Navy standard NRL Report 8093 requires the absorbing material for electromagnetic anechoic chambers to meet the requirements of items 1, 2, and 3 of this standard.

目前市场上的聚丙烯泡沫吸波材料很难满足这两项标准，专利号为201710970210.7，专利名称为一种高导电高阻燃型聚丙烯发泡珠粒的制备方法的专利，实施例中电阻800-1350欧姆的板材能达到氧指数28，制备的板材样品压制板材时可以提高压制密度，提高板材压制密度对提升氧指数有一点帮助，但如要生产角锥型吸波材料则氧指数不能达到28，氧指数更不可能达到大于32的氧指数值，201710970210.7专利实施例中平板状吸波材料在特定频率200M-1.2G有一定吸收效果，依据吸波材料阻抗匹配设计，满足201710970210.7，专利实施例中200M时有-28dB吸收率条件至少需要500-700mm高角锥型吸波材料，或者为软磁铁氧体片吸波材料且只有200M-1.2G吸收率曲线上谐振峰的顶部几个频点等够达到，虽然201710970210.7实施例中并未描述实施例板材厚度，但无论何种单层厚度的电阻损耗型板材都不能满足200M时28和400M时69的吸收率，其他实施例也是如此，明显此专利方法只能应用与特定频率，不能够满足应用于电磁波暗室角锥型吸波材料宽频段吸收率和阻燃的需求；专利申请号为CN202110787462.2的专利，实施例中也是单层板材吸波材料200M时吸收率≥37，同样原理也是无论何种厚度的单层电阻损耗型吸波材料板材都不能达到这样的指标，所以此专利方法也是只能应用与特定频率，如要生产角锥型吸波材料则氧指数也不能达到28，氧指数更不能达到大于32，所以此种方法也不能够满足应用于电磁波暗室角锥型吸波材料宽频段吸收率和阻燃的需求；Currently available polypropylene foam absorbing materials rarely meet these two standards. Patent number 201710970210.7, entitled "A Method for Preparing Highly Conductive and Highly Flame-Retardant Polypropylene Foamed Beads," states that in the examples, a board with a resistance of 800-1350 ohms can achieve an oxygen index of 28. Increasing the pressing density of the prepared board samples can slightly improve the oxygen index, but if a pyramidal absorbing material is to be produced, the oxygen index cannot reach 28. It is even less likely that the oxygen index value will reach a value greater than 32. In the embodiment of patent 201710970210.7, the flat plate absorbing material has a certain absorption effect at a specific frequency of 200M-1.2G. According to the impedance matching design of the absorbing material, to meet the condition of -28dB absorption rate at 200M in the patent embodiment of 201710970210.7, at least a 500-700mm high pyramidal absorbing material is required, or a soft magnetic ferrite sheet absorbing material with an absorption rate of only 200M-1.2G. The top few frequency points of the resonance peak on the curve can be reached. Although the thickness of the plate material in the embodiment 201710970210.7 is not described, no single-layer thickness of the resistive loss type plate material can meet the absorption rate of 28 at 200M and 69 at 400M. The same is true for other embodiments. Obviously, this patented method can only be applied to specific frequencies and cannot meet the requirements of wide-band absorption rate and flame retardancy for use in electromagnetic anechoic chamber pyramidal absorbing materials. In the patent application with patent application number CN202110787462.2, the absorption rate of the single-layer plate absorbing material at 200M is ≥37. The same principle is that no single-layer resistive loss type absorbing material plate material of any thickness can achieve such indicators. Therefore, this patented method can only be applied to specific frequencies. If pyramidal absorbing materials are to be produced, the oxygen index cannot reach 28, let alone greater than 32. Therefore, this method cannot meet the requirements of wide-band absorption rate and flame retardancy for use in electromagnetic anechoic chamber pyramidal absorbing materials.

发泡聚丙烯或聚乙烯泡沫吸波材料是将导电剂，阻燃剂，及成核剂混合后 造粒，通过超临界二氧化碳发泡工艺，要优先满足吸收电磁波特性，就要添加比较多的导电剂，如要制得发泡后还能通过泡沫成型机成型的材料，那留给能够添加阻燃剂的比例就相对比较少，所以最终制成的聚丙烯或聚乙烯泡沫吸波材料氧指数很难高于28。Foamed polypropylene or polyethylene foam microwave absorbing materials are made by mixing conductive agents, flame retardants, and nucleating agents. In granulation, using supercritical carbon dioxide foaming technology, to prioritize the absorption of electromagnetic waves, a relatively large amount of conductive agent needs to be added. If the goal is to produce a material that can still be molded by a foam molding machine after foaming, then the proportion of flame retardant that can be added is relatively small. Therefore, the oxygen index of the final polypropylene or polyethylene foam microwave absorbing material is difficult to exceed 28.

发明内容Summary of the Invention

本发明的目的是在于克服、补充现有技术中存在的不足，提供一种高阻燃含膨胀石墨聚合物泡沫吸波材料及其制备方法，由于膨胀石墨遇热会膨胀数倍特性，膨胀后隔绝氧气，是非常好的阻燃材料，但是一般膨胀石墨的颗粒相对较大，不能像其他粉末材料熔融在聚合物里再进行发泡，因此将高填充膨胀石墨用胶黏剂形式包覆在聚丙烯或聚乙烯泡沫颗粒表面，由于胶黏剂在聚丙烯或聚乙烯泡沫颗粒表面附着力较差的因素，所以将制备的导电聚合物泡沫颗粒与附着力促进剂预处理后再与含膨胀石墨复合树脂泡沫颗粒混合，制备出电磁波暗室用聚合物泡沫吸波材料要求氧指数大于28，尤其是氧指数达到大于32，以及满足NRLReport8093标准的1、2、3项指标的吸波材料。The purpose of this invention is to overcome and supplement the shortcomings of the existing technology, and to provide a high flame-retardant polymer foam absorbing material containing expanded graphite and its preparation method. Due to the property that expanded graphite expands several times when heated, it isolates oxygen after expansion, making it an excellent flame-retardant material. However, the particles of expanded graphite are generally relatively large and cannot be melted into polymers and then foamed like other powder materials. Therefore, highly filled expanded graphite is coated onto the surface of polypropylene or polyethylene foam particles in the form of an adhesive. Due to the poor adhesion of the adhesive to the surface of polypropylene or polyethylene foam particles, the prepared conductive polymer foam particles are pretreated with an adhesion promoter and then mixed with expanded graphite-containing composite resin foam particles to prepare a polymer foam absorbing material for electromagnetic anechoic chambers. The material requires an oxygen index greater than 28, especially an oxygen index greater than 32, and meets the 1st, 2nd, and 3rd indicators of the NRL Report 8093 standard.

本发明采用的技术方案是：The technical solution adopted in this invention is:

一种高阻燃含膨胀石墨聚合物泡沫吸波材料，其中：按体积份计，包括导电聚合物泡沫颗粒0-90份，含膨胀石墨复合树脂泡沫颗粒10-100份。A highly flame-retardant wave-absorbing material containing expanded graphite polymer foam, wherein, by volume, it comprises 0-90 parts of conductive polymer foam particles and 10-100 parts of expanded graphite composite resin foam particles.

优选的是，所述的高阻燃含膨胀石墨聚合物泡沫吸波材料，其中：按重量份计，所述含膨胀石墨复合树脂泡沫颗粒包括导电聚合物泡沫颗粒30-95份和包覆涂料5-70份，包覆涂料包括胶黏剂5-50份、导电剂1-30份、第一阻燃剂0-20份、膨胀石墨20-95份、溶剂13-300份。Preferably, the high flame-retardant expanded graphite polymer foam absorbing material comprises, by weight, 30-95 parts of conductive polymer foam particles and 5-70 parts of coating material, wherein the coating material comprises 5-50 parts of adhesive, 1-30 parts of conductive agent, 0-20 parts of first flame retardant, 20-95 parts of expanded graphite, and 13-300 parts of solvent.

优选的是，所述的高阻燃含膨胀石墨聚合物泡沫吸波材料，其中：所述导电聚合物泡沫颗粒选自聚丙烯泡沫颗粒和聚乙烯泡沫颗粒中的一种，所述聚丙烯泡沫颗粒或聚乙烯泡沫颗粒均包括至少一种聚丙烯树脂或聚乙烯树脂，按重量份计，每种所述聚丙烯树脂或聚乙烯树脂均包括以下组分：聚丙烯或聚乙烯45-95份、导电剂5-35份、分散剂1-10份、第一阻燃剂1-20份、成核剂0.1-1份。Preferably, the high flame-retardant expanded graphite polymer foam absorbing material comprises: the conductive polymer foam particles selected from polypropylene foam particles and polyethylene foam particles, wherein each polypropylene foam particle or polyethylene foam particle includes at least one polypropylene resin or polyethylene resin, and each polypropylene resin or polyethylene resin comprises the following components by weight: 45-95 parts of polypropylene or polyethylene, 5-35 parts of conductive agent, 1-10 parts of dispersant, 1-20 parts of first flame retardant, and 0.1-1 parts of nucleating agent.

优选的是，所述的高阻燃含膨胀石墨聚合物泡沫吸波材料，其中：所述导电剂选自炭黑、石墨、石墨烯、碳纳米管或金属粉末的一种或多种；所述第一阻燃剂选自包覆红磷、聚磷酸铵、磷酸二氢铝、季戊四醇磷酸酯、溴化聚苯乙烯中的一种或多种。Preferably, in the high flame-retardant expanded graphite polymer foam microwave absorbing material: the conductive agent is selected from one or more of carbon black, graphite, graphene, carbon nanotubes or metal powder; the first flame retardant is selected from one or more of coated red phosphorus, ammonium polyphosphate, aluminum dihydrogen phosphate, pentaerythritol phosphate, and brominated polystyrene.

优选的是，所述的高阻燃含膨胀石墨聚合物泡沫吸波材料，其中：所述分散剂选自PE蜡和磷酸三苯酯中的一种或两种。Preferably, in the high flame-retardant expanded graphite polymer foam microwave absorbing material, the dispersant is selected from one or two of PE wax and triphenyl phosphate.

优选的是，所述的高阻燃含膨胀石墨聚合物泡沫吸波材料，其中：所述胶黏剂选自酚醛、丙烯酸树脂、乙烯丙烯酸共聚物、聚醋酸乙烯酯、聚氨酯胶黏剂和有机硅树脂中的一种或多种。Preferably, in the high flame-retardant expanded graphite polymer foam microwave absorbing material, the adhesive is selected from one or more of phenolic resin, acrylic resin, ethylene-acrylic acid copolymer, polyvinyl acetate, polyurethane adhesive and silicone resin.

优选的是，所述的高阻燃含膨胀石墨聚合物泡沫吸波材料，其中：所述导电聚合物泡沫颗粒外表面还包覆附着力促进剂，所述导电聚合物泡沫颗粒和附着力促进剂的质量比为80-99：1-20。 Preferably, in the high flame-retardant expanded graphite polymer foam absorbing material, the outer surface of the conductive polymer foam particles is further coated with an adhesion promoter, and the mass ratio of the conductive polymer foam particles to the adhesion promoter is 80-99:1-20.

优选的是，所述的高阻燃含膨胀石墨聚合物泡沫吸波材料，其中：所述附着力促进剂为氯化聚丙烯溶液。Preferably, in the high flame-retardant expanded graphite polymer foam absorbing material, the adhesion promoter is a chlorinated polypropylene solution.

一种高阻燃含膨胀石墨聚合物泡沫吸波材料的制备方法，其中：包括如下步骤：A method for preparing a highly flame-retardant expanded graphite polymer foam microwave absorbing material, comprising the following steps:

步骤S1：按重量份计，将45-95份聚丙烯或聚乙烯、5-35份导电剂、1-10份分散剂，1-20份第一阻燃剂混合均匀得到第一混合物，随后将第一混合物用密炼机混合后通过双螺杆挤出机挤出得到至少一种0.3-2mg的聚丙烯树脂或聚乙烯树脂；Step S1: By weight, 45-95 parts of polypropylene or polyethylene, 5-35 parts of conductive agent, 1-10 parts of dispersant, and 1-20 parts of first flame retardant are mixed evenly to obtain a first mixture. Then, the first mixture is mixed in an internal mixer and extruded through a twin-screw extruder to obtain at least 0.3-2 mg of polypropylene resin or polyethylene resin.

步骤S2：将步骤S1的至少一种聚丙烯树脂或聚乙烯树脂加入高压反应釜，并向高压反应釜中加入水、表面活性剂，随后开启搅拌，加热并通入氮气或者二氧化碳，持续加热至聚丙烯树脂或聚乙烯树脂熔点时，放出物料发泡制得聚丙烯泡沫颗粒或聚乙烯泡沫颗粒，得到导电聚合物泡沫颗粒；Step S2: Add at least one polypropylene resin or polyethylene resin from step S1 to a high-pressure reactor, and add water and surfactant to the high-pressure reactor. Then start stirring, heat and introduce nitrogen or carbon dioxide. Continue heating until the melting point of the polypropylene resin or polyethylene resin is reached, and release the material to foam and obtain polypropylene foam particles or polyethylene foam particles, thus obtaining conductive polymer foam particles.

步骤S3：按重量份计，将5-50份胶黏剂、1-30份导电剂、1-30份第一阻燃剂、20-95份膨胀石墨和13-300份溶剂加入分散机中分散均匀，得到包覆涂料；Step S3: By weight, add 5-50 parts of adhesive, 1-30 parts of conductive agent, 1-30 parts of first flame retardant, 20-95 parts of expanded graphite and 13-300 parts of solvent to a disperser and disperse evenly to obtain a coating.

步骤S4：按重量份计，将步骤S3的30-95份导电聚合物泡沫颗粒加入搅拌桶中，随后加入S4的5-70份包覆涂料并搅拌得到第二混合物，并将第二混合物加入风干设备中干燥，过筛得到含膨胀石墨复合树脂泡沫颗粒；Step S4: By weight, add 30-95 parts of conductive polymer foam particles from step S3 to a mixing tank, then add 5-70 parts of coating material from S4 and stir to obtain a second mixture. Add the second mixture to a drying device to dry and sieve to obtain foam particles containing expanded graphite composite resin.

步骤S5：按体积份计，将0-90份导电聚合物泡沫颗粒和10-100份含膨胀石墨复合树脂泡沫颗粒混合得到第三混合物，随后将第三混合物成型得到吸波材料。Step S5: By volume, 0-90 parts of conductive polymer foam particles and 10-100 parts of expanded graphite composite resin foam particles are mixed to obtain a third mixture, and then the third mixture is molded to obtain a microwave absorbing material.

一种高阻燃含膨胀石墨聚合物泡沫吸波材料的制备方法，其中：按重量份计，包括如下步骤：A method for preparing a highly flame-retardant expanded graphite polymer foam microwave absorbing material, comprising the following steps by weight:

步骤S1：按重量份计，将45-95份聚丙烯或聚乙烯、5-35份导电剂、1-10份分散剂，1-20份第一阻燃剂混合均匀得到第一混合物，随后将第一混合物用密炼机混合后通过双螺杆挤出机挤出得到至少一种0.3-2mg的聚丙烯树脂或聚乙烯树脂；Step S1: By weight, 45-95 parts of polypropylene or polyethylene, 5-35 parts of conductive agent, 1-10 parts of dispersant, and 1-20 parts of first flame retardant are mixed evenly to obtain a first mixture. Then, the first mixture is mixed in an internal mixer and extruded through a twin-screw extruder to obtain at least 0.3-2 mg of polypropylene resin or polyethylene resin.

步骤S2：将步骤S1的至少一种聚丙烯树脂或聚乙烯树脂加入高压反应釜，并向高压反应釜中加入水、表面活性剂，随后开启搅拌，加热并通入氮气或者二氧化碳，持续加热至聚丙烯树脂或聚乙烯树脂熔点时，放出物料发泡制得聚丙烯泡沫颗粒、聚乙烯泡沫颗粒，得到导电聚合物泡沫颗粒；Step S2: Add at least one polypropylene resin or polyethylene resin from step S1 to a high-pressure reactor, and add water and surfactant to the high-pressure reactor. Then start stirring, heat and introduce nitrogen or carbon dioxide. Continue heating until the melting point of polypropylene resin or polyethylene resin is reached, and release the material to foam and obtain polypropylene foam particles and polyethylene foam particles, thus obtaining conductive polymer foam particles.

步骤S3：按重量份计，将步骤S2的80-99份导电聚合物泡沫颗粒与1-20份附着力促进剂混合加入风干设备中干燥，得到复合泡沫颗粒；Step S3: By weight, mix 80-99 parts of conductive polymer foam particles from step S2 with 1-20 parts of adhesion promoter and add them to an air-drying device to dry, thereby obtaining composite foam particles.

步骤S4：按重量份计，将5-50份胶黏剂、1-30份导电剂、1-30份第一阻燃剂、20-95份膨胀石墨和13-300份溶剂加入分散机中分散均匀，得到包覆涂料；Step S4: By weight, add 5-50 parts of adhesive, 1-30 parts of conductive agent, 1-30 parts of first flame retardant, 20-95 parts of expanded graphite and 13-300 parts of solvent to a disperser and disperse evenly to obtain a coating.

步骤S5：按重量份计，将步骤S3的30-95份复合泡沫颗粒加入搅拌桶中，随后加入S4的5-70份包覆涂料并搅拌得到第二混合物，并将第二混合物加入风干设备中干燥，过筛得到含膨胀石墨复合树脂泡沫颗粒； Step S5: By weight, add 30-95 parts of the composite foam particles from step S3 to a mixing tank, then add 5-70 parts of the coating material from S4 and stir to obtain a second mixture. Add the second mixture to a drying equipment to dry, and sieve to obtain foam particles containing expanded graphite composite resin.

步骤S6：按体积份计，将0-90份复合泡沫颗粒和10-100份含膨胀石墨复合树脂泡沫颗粒混合得到第三混合物，随后将第三混合物成型得到吸波材料。Step S6: Mix 0-90 parts of composite foam particles and 10-100 parts of expanded graphite composite resin foam particles by volume to obtain a third mixture, and then mold the third mixture to obtain a microwave absorbing material.

本发明的优点：Advantages of this invention:

(1)本发明将红磷与膨胀石墨协同作用，作为阻燃剂红磷遇热燃烧产生五氧化二磷，膨胀石墨在聚合物高温燃烧时，吸附石墨插层中硫酸化合物开始分解反应，膨胀石墨鳞片垂直方向开始膨胀，膨胀至自身的数百倍形成石墨蠕虫，硫酸化合物分解产生SO2、CO2和水，聚丙烯或聚乙烯燃烧产生CO2和水，红磷燃烧生成的五氧化二磷捕捉膨胀石墨插层中硫酸化合物分解反应以及聚合物燃烧产生的水蒸汽分子，形成磷酸晶体水合物H3PO4，在聚合物燃烧时膨胀石墨膨胀形成石墨蠕虫交错支撑在燃烧的聚合物表面，以及聚合物表面燃烧被红磷燃烧形成的酸催化成炭，和聚合物中炭黑、石墨等无机物粉末，被红磷燃烧形成的磷酸晶体水合物H3PO4，浓稠的油状物将这些物质连接在一起形成一层立体且致密的隔绝氧气结构，由于膨胀石墨蠕虫交错支撑在聚合物表面和红磷燃烧形成的磷酸晶体水合物H3PO4浓稠的油状物形成隔绝氧气的立体结构，这样的协同作用可以有效的隔绝氧气的进入，从而提高了吸波材料的阻燃效果，电磁波暗室用聚合物泡沫吸波材料要求氧指数大于28，本发明的吸波材料实际氧指数能达到大于32，满足NRLReport8093标准的1、2、3项指标。(1) This invention utilizes the synergistic effect of red phosphorus and expanded graphite as a flame retardant. Red phosphorus burns upon heating to produce phosphorus pentoxide. When the polymer burns at high temperatures, the expanded graphite adsorbs the sulfuric acid compounds in the graphite intercalation and begins to decompose. The expanded graphite flakes expand vertically, expanding to hundreds of times their original size to form graphite worms. The sulfuric acid compounds decompose to produce SO2 , CO2 , and water. The combustion of polypropylene or polyethylene produces CO2 and water. The phosphorus pentoxide generated by the combustion of red phosphorus captures the decomposition reaction of sulfuric acid compounds in the expanded graphite intercalation and the water vapor molecules generated by the combustion of the polymer, forming phosphate hydrate H3PO4 . During polymer combustion, the expanded graphite expands to form graphite worms that interweave and support the burning polymer surface. The polymer surface is also catalyzed by the acid formed by the combustion of red phosphorus to form carbon, and the inorganic powders such as carbon black and graphite in the polymer are also hydrated into phosphate hydrate H3PO4 by the combustion of red phosphorus . The thick, oily substance binds these substances together to form a three-dimensional and dense oxygen-barrier structure. Due to the interlacing support of expanded graphite worms on the polymer surface and the phosphate crystal hydrate H3PO4 formed by the combustion of red phosphorus, a three -dimensional oxygen-barrier structure is formed. This synergistic effect can effectively prevent the entry of oxygen, thereby improving the flame retardant effect of the microwave absorbing material. The polymer foam microwave absorbing material for electromagnetic anechoic chambers requires an oxygen index greater than 28. The microwave absorbing material of this invention can actually achieve an oxygen index greater than 32, meeting the 1st, 2nd, and 3rd indicators of the NRLReport8093 standard.

(2)本发明采用加压式密炼机将导电剂及各粉末助剂密炼后再造粒，由于配方比例准确，可确保吸波材料电磁参数的介电常数与损耗角正切的性能指标稳定性与批次一致性。(2) The present invention uses a pressure mixer to mix the conductive agent and various powder additives and then granulate them. Due to the accurate formula ratio, the stability and batch consistency of the dielectric constant and loss tangent of the electromagnetic parameters of the absorbing material can be ensured.

(3)本发明包覆涂料中第一阻燃剂0-20份，由于膨胀石墨具有导电性，在生产多层复合吸波材料时需要调节每层材料的电磁参数，以及生产高频、超高频或太赫兹吸波材料时，需要调节电磁参数，降低膨胀石墨比例，以不导电的第一阻燃剂代替部分膨胀石墨调节电磁参数，阻燃效果虽然没有高填充膨胀石墨好，但是也能达到吸波材料阻燃基础指标氧指数大于28的阻燃需求。(3) The first flame retardant in the coating of the present invention is 0-20 parts. Since expanded graphite is conductive, it is necessary to adjust the electromagnetic parameters of each layer of material when producing multi-layer composite microwave absorbing materials. When producing high-frequency, ultra-high-frequency or terahertz microwave absorbing materials, it is necessary to adjust the electromagnetic parameters and reduce the proportion of expanded graphite. The non-conductive first flame retardant is used to replace part of the expanded graphite to adjust the electromagnetic parameters. Although the flame retardant effect is not as good as that of high-filled expanded graphite, it can still meet the flame retardant requirement of the basic flame retardant index of microwave absorbing materials being greater than 28.

(4)本发明的高阻燃含膨胀石墨聚合物泡沫吸波材料可替代传统聚氨酯海绵吸波材料，电磁波暗室拆除后聚合物泡沫吸波材料可以回收熔融再加工成其他塑料制品，传统聚氨酯海绵吸波材料拆除报废后只能焚烧处理，本发明的聚合物泡沫吸波材料可降低环境污染，低吸水率和高氧指数特性还可应用在室外及军用伪装领域，应用前景较为广泛。(4) The high flame-retardant polymer foam absorbing material containing expanded graphite of the present invention can replace the traditional polyurethane sponge absorbing material. After the electromagnetic wave anechoic chamber is dismantled, the polymer foam absorbing material can be recycled, melted and reprocessed into other plastic products. The traditional polyurethane sponge absorbing material can only be incinerated after it is dismantled and scrapped. The polymer foam absorbing material of the present invention can reduce environmental pollution. Its low water absorption rate and high oxygen index characteristics can also be applied in outdoor and military camouflage fields, and its application prospects are relatively broad.

附图说明Attached Figure Description

图1为实施例1-9制备得到的含膨胀石墨复合树脂泡沫颗粒的SEM图。Figure 1 shows the SEM images of the expanded graphite composite resin foam particles prepared in Examples 1-9.

图2为实施例1-9制备得到的含膨胀石墨复合树脂泡沫颗粒切开后的SEM图。Figure 2 is a SEM image of the expanded graphite composite resin foam particles prepared in Examples 1-9 after being cut open.

图3为本发明实施例1-9和对比例1-2制备的500高吸波角锥吸波材料的结构示意图。Figure 3 is a schematic diagram of the structure of the 500 high-absorbing cone microwave absorbing material prepared in Examples 1-9 and Comparative Examples 1-2 of the present invention.

具体实施方式Detailed Implementation

下面结合具体附图和实施例对本发明作进一步说明。The present invention will be further described below with reference to specific accompanying drawings and embodiments.

实施例1 Example 1

一种高阻燃含膨胀石墨聚合物泡沫吸波材料的制备方法，包括如下步骤：A method for preparing a highly flame-retardant microwave absorbing material containing expanded graphite polymer foam includes the following steps:

步骤S1：按重量份计，将62.9份聚丙烯、25份导电炭黑、2份PE蜡、0.1份硼酸锌、8份包覆红磷混合均匀得到第一混合物，随后将第一混合物用密炼机混合后通过双螺杆挤出机挤出，双螺杆挤出机共有十一段，挤出温度依次为：第一段140°、第二段150°、第三段165°、第四段175°、第五段180°第六段185°、第七段192℃、第八段185°、第九段192°、第十段185°、第十一段192°，模头210°，得到0.3-2mg聚丙烯树脂；Step S1: By weight, 62.9 parts of polypropylene, 25 parts of conductive carbon black, 2 parts of PE wax, 0.1 parts of zinc borate, and 8 parts of coated red phosphorus are mixed evenly to obtain a first mixture. Then, the first mixture is mixed in an internal mixer and extruded through a twin-screw extruder. The twin-screw extruder has eleven stages, and the extrusion temperatures are as follows: stage 1 140°C, stage 2 150°C, stage 3 165°C, stage 4 175°C, stage 5 180°C, stage 6 185°C, stage 7 192°C, stage 8 185°C, stage 9 192°C, stage 10 185°C, stage 11 192°C, and the die is 210°C, to obtain 0.3-2 mg of polypropylene resin.

步骤S2：将步骤S1得到的聚丙烯树脂加入高压反应釜，向高压反应釜中加入所投入聚丙烯树脂重量2倍的水和所加入水重量3％的十二烷基苯磺酸钠，开启搅拌，加热并通入二氧化碳，压力为3.5mpa，反应釜温度为140℃，放出物料发泡、清洗、烘干制得密度为45kg/m3的聚丙烯泡沫颗粒，得到导电聚合物泡沫颗粒；Step S2: Add the polypropylene resin obtained in step S1 to a high-pressure reactor. Add water with a weight of 2 times that of the added polypropylene resin and sodium dodecylbenzenesulfonate with a weight of 3% of the added water to the high-pressure reactor. Start stirring, heat and introduce carbon dioxide. The pressure is 3.5 MPa and the reactor temperature is 140°C. Release the material, foam, wash and dry to obtain polypropylene foam particles with a density of 45 kg/ m3 , and obtain conductive polymer foam particles.

步骤S3：按重量份计，将28份聚醋酸乙烯酯、5份导电炭黑、67份80目膨胀石墨和60份乙醇加入分散机中分散均匀，分散机转速1500转，分散30分钟，得到包覆涂料；Step S3: By weight, add 28 parts of polyvinyl acetate, 5 parts of conductive carbon black, 67 parts of 80-mesh expanded graphite and 60 parts of ethanol to a disperser and disperse evenly. The disperser speed is 1500 rpm and the dispersion time is 30 minutes to obtain the coating.

步骤S4：按重量份计，将步骤S3得到的20kg导电聚合物泡沫颗粒加入搅拌桶中，随后加入30kg包覆涂料并搅拌得到第二混合物，搅拌速度80转/分钟，并将第二混合物加入风干设备中干燥，主轴破碎电机设置30转/分钟，干燥破碎20分钟，过筛得到含膨胀石墨复合树脂泡沫颗粒；Step S4: By weight, add 20kg of conductive polymer foam particles obtained in step S3 to a mixing tank, then add 30kg of coating material and stir to obtain a second mixture. The stirring speed is 80 rpm. The second mixture is then added to a drying device for drying. The main shaft crushing motor is set to 30 rpm. The drying and crushing process takes 20 minutes. The mixture is then sieved to obtain foam particles containing expanded graphite composite resin.

步骤S5：按体积份计，将步骤S3得到的50L导电聚合物泡沫颗粒和50L含膨胀石墨复合树脂泡沫颗粒混合得到第三混合物，随后将第三混合物成型得到500高角锥吸波材料。Step S5: By volume, the 50L conductive polymer foam particles and 50L expanded graphite composite resin foam particles obtained in step S3 are mixed to obtain a third mixture, and then the third mixture is molded to obtain a 500 high-angle pyramidal microwave absorbing material.

实施例2Example 2

一种高阻燃含膨胀石墨聚合物泡沫吸波材料的制备方法，包括如下步骤：A method for preparing a highly flame-retardant microwave absorbing material containing expanded graphite polymer foam includes the following steps:

步骤S1：按重量份计，将62.9份聚丙烯、25份导电炭黑、2份PE蜡、0.1份硼酸锌、8份包覆红磷混合均匀得到第一混合物，随后将第一混合物用密炼机混合后通过双螺杆挤出机挤出，双螺杆挤出机共有十一段，挤出温度依次为：第一段140°、第二段150°、第三段165°、第四段175°、第五段180°第六段185°、第七段192℃、第八段185°、第九段192°、第十段185°、第十一段192°，模头210°，得到0.3-2mg聚丙烯树脂；Step S1: By weight, 62.9 parts of polypropylene, 25 parts of conductive carbon black, 2 parts of PE wax, 0.1 parts of zinc borate, and 8 parts of coated red phosphorus are mixed evenly to obtain a first mixture. Then, the first mixture is mixed in an internal mixer and extruded through a twin-screw extruder. The twin-screw extruder has eleven stages, and the extrusion temperatures are as follows: stage 1 140°C, stage 2 150°C, stage 3 165°C, stage 4 175°C, stage 5 180°C, stage 6 185°C, stage 7 192°C, stage 8 185°C, stage 9 192°C, stage 10 185°C, stage 11 192°C, and the die is 210°C, to obtain 0.3-2 mg of polypropylene resin.

步骤S2：将步骤S1得到的聚丙烯树脂加入高压反应釜，向高压反应釜中加入所投入聚丙烯树脂重量2倍的水和所加入水重量3％的十二烷基苯磺酸钠，开启搅拌，加热并通入二氧化碳，压力为3.5mpa，反应釜温度为140℃，放出物料发泡、清洗、烘干制得密度为45kg/m3的聚丙烯泡沫颗粒，得到导电聚合物泡沫颗粒；Step S2: Add the polypropylene resin obtained in step S1 to a high-pressure reactor. Add water with a weight of 2 times that of the added polypropylene resin and sodium dodecylbenzenesulfonate with a weight of 3% of the added water to the high-pressure reactor. Start stirring, heat and introduce carbon dioxide. The pressure is 3.5 MPa and the reactor temperature is 140°C. Release the material, foam, wash and dry to obtain polypropylene foam particles with a density of 45 kg/ m3 , and obtain conductive polymer foam particles.

步骤S3：按重量份计，将28份聚醋酸乙烯酯、5份导电炭黑、67份80目膨胀石墨和60份乙醇加入分散机中分散均匀，分散机转速1500转，分散30分钟，得到包覆涂料；Step S3: By weight, add 28 parts of polyvinyl acetate, 5 parts of conductive carbon black, 67 parts of 80-mesh expanded graphite and 60 parts of ethanol to a disperser and disperse evenly. The disperser speed is 1500 rpm and the dispersion time is 30 minutes to obtain the coating.

步骤S4：按重量份计，将步骤S3得到的20kg导电聚合物泡沫颗粒加入搅 拌桶中，随后加入30kg包覆涂料并搅拌得到第二混合物，搅拌速度80转/分钟，并将第二混合物加入风干设备中干燥，主轴破碎电机设置30转/分钟，干燥破碎20分钟，过筛得到含膨胀石墨复合树脂泡沫颗粒；Step S4: By weight, add 20 kg of conductive polymer foam particles obtained in step S3 to the mixer. In the mixing tank, 30 kg of coating material was added and stirred to obtain a second mixture. The stirring speed was 80 rpm. The second mixture was then added to the air drying equipment for drying. The main shaft crushing motor was set to 30 rpm. The drying and crushing were carried out for 20 minutes. The mixture was then sieved to obtain foam particles containing expanded graphite composite resin.

步骤S5：按体积份计，将步骤S3得到的60L导电聚合物泡沫颗粒和40L含膨胀石墨复合树脂泡沫颗粒混合得到第三混合物，随后将第三混合物成型得到500高角锥吸波材料。Step S5: By volume, the 60L conductive polymer foam particles and 40L expanded graphite composite resin foam particles obtained in step S3 are mixed to obtain a third mixture, and then the third mixture is molded to obtain a 500 high-angle pyramidal microwave absorbing material.

实施例3Example 3

一种高阻燃含膨胀石墨聚合物泡沫吸波材料的制备方法，包括如下步骤：A method for preparing a highly flame-retardant microwave absorbing material containing expanded graphite polymer foam includes the following steps:

步骤S1：按重量份计，将62.9份聚丙烯、25份导电炭黑、2份PE蜡、0.1份硼酸锌、8份包覆红磷混合均匀得到第一混合物，随后将第一混合物用密炼机混合后通过双螺杆挤出机挤出，双螺杆挤出机共有十一段，挤出温度依次为：第一段140°、第二段150°、第三段165°、第四段175°、第五段180°第六段185°、第七段192℃、第八段185°、第九段192°、第十段185°、第十一段192°，模头210°，得到0.3-2mg聚丙烯树脂；Step S1: By weight, 62.9 parts of polypropylene, 25 parts of conductive carbon black, 2 parts of PE wax, 0.1 parts of zinc borate, and 8 parts of coated red phosphorus are mixed evenly to obtain a first mixture. Then, the first mixture is mixed in an internal mixer and extruded through a twin-screw extruder. The twin-screw extruder has eleven stages, and the extrusion temperatures are as follows: stage 1 140°C, stage 2 150°C, stage 3 165°C, stage 4 175°C, stage 5 180°C, stage 6 185°C, stage 7 192°C, stage 8 185°C, stage 9 192°C, stage 10 185°C, stage 11 192°C, and the die is 210°C, to obtain 0.3-2 mg of polypropylene resin.

步骤S2：将步骤S1得到的聚丙烯树脂加入高压反应釜，向高压反应釜中加所投入聚丙烯树脂重量2倍的水和所加入水重量3％的十二烷基苯磺酸钠，开启搅拌，加热并通入二氧化碳，压力为3.5mpa，反应釜温度为140℃，放出物料发泡、清洗、烘干制得密度为45kg/m3的聚丙烯泡沫颗粒，得到导电聚合物泡沫颗粒；Step S2: Add the polypropylene resin obtained in step S1 to a high-pressure reactor. Add water with a weight of 2 times that of the added polypropylene resin and sodium dodecylbenzenesulfonate with a weight of 3% of the added water to the high-pressure reactor. Start stirring, heat and introduce carbon dioxide. The pressure is 3.5 MPa and the reactor temperature is 140°C. Release the material, foam, wash and dry to obtain polypropylene foam particles with a density of 45 kg/ m³ , and obtain conductive polymer foam particles.

步骤S3：按重量份计，将28份聚醋酸乙烯酯、5份导电炭黑、67份80目膨胀石墨和60份乙醇加入分散机中分散均匀，分散机转速1500转，分散30分钟，得到包覆涂料；Step S3: By weight, add 28 parts of polyvinyl acetate, 5 parts of conductive carbon black, 67 parts of 80-mesh expanded graphite and 60 parts of ethanol to a disperser and disperse evenly. The disperser speed is 1500 rpm and the dispersion time is 30 minutes to obtain the coating.

步骤S4：按重量份计，将步骤S3得到的20kg导电聚合物泡沫颗粒加入搅拌桶中，随后加入30kg包覆涂料并搅拌得到第二混合物，搅拌速度80转/分钟，并将第二混合物加入风干设备中干燥，主轴破碎电机设置30转/分钟，干燥破碎20分钟，过筛得到含膨胀石墨复合树脂泡沫颗粒；Step S4: By weight, add 20kg of conductive polymer foam particles obtained in step S3 to a mixing tank, then add 30kg of coating material and stir to obtain a second mixture. The stirring speed is 80 rpm. The second mixture is then added to a drying device for drying. The main shaft crushing motor is set to 30 rpm. The drying and crushing process takes 20 minutes. The mixture is then sieved to obtain foam particles containing expanded graphite composite resin.

步骤S5：按体积份计，将步骤S3得到的70L导电聚合物泡沫颗粒和30L含膨胀石墨复合树脂泡沫颗粒混合得到第三混合物，随后将第三混合物成型得到500高角锥吸波材料。Step S5: By volume, mix the 70L conductive polymer foam particles and 30L expanded graphite composite resin foam particles obtained in step S3 to obtain a third mixture, and then mold the third mixture to obtain a 500 high-angle pyramidal microwave absorbing material.

实施例4Example 4

一种高阻燃含膨胀石墨聚合物泡沫吸波材料的制备方法，包括如下步骤：A method for preparing a highly flame-retardant microwave absorbing material containing expanded graphite polymer foam includes the following steps:

步骤S1：按重量份计，将62.9份聚丙烯、25份导电炭黑、2份PE蜡、0.1份硼酸锌、8份包覆红磷混合均匀得到第一混合物，随后将第一混合物用密炼机混合后通过双螺杆挤出机挤出，双螺杆挤出机共有十一段，挤出温度依次为：第一段140°、第二段150°、第三段165°、第四段175°、第五段180°第六段185°、第七段192℃、第八段185°、第九段192°、第十段185°、第十一段192°，模头210°，得到0.3-2mg聚丙烯树脂；Step S1: By weight, 62.9 parts of polypropylene, 25 parts of conductive carbon black, 2 parts of PE wax, 0.1 parts of zinc borate, and 8 parts of coated red phosphorus are mixed evenly to obtain a first mixture. Then, the first mixture is mixed in an internal mixer and extruded through a twin-screw extruder. The twin-screw extruder has eleven stages, and the extrusion temperatures are as follows: stage 1 140°C, stage 2 150°C, stage 3 165°C, stage 4 175°C, stage 5 180°C, stage 6 185°C, stage 7 192°C, stage 8 185°C, stage 9 192°C, stage 10 185°C, stage 11 192°C, and the die is 210°C, to obtain 0.3-2 mg of polypropylene resin.

步骤S2：将步骤S1得到的聚丙烯树脂加入高压反应釜，向高压反应釜中加入所投入聚丙烯树脂重量2倍的水和所加入水重量3％的十二烷基苯磺酸钠， 开启搅拌，加热并通入二氧化碳，压力为3.5mpa，反应釜温度为140℃，放出物料发泡、清洗、烘干制得密度为45kg/m3的聚丙烯泡沫颗粒，得到导电聚合物泡沫颗粒；Step S2: Add the polypropylene resin obtained in step S1 to a high-pressure reactor, and add water equal to twice the weight of the added polypropylene resin and sodium dodecylbenzenesulfonate at 3% of the weight of the added water to the high-pressure reactor. Stirring was started, heating was carried out and carbon dioxide was introduced. The pressure was 3.5 MPa and the temperature of the reactor was 140℃. The material was released, foamed, washed and dried to obtain polypropylene foam particles with a density of 45 kg/ m3 , thus obtaining conductive polymer foam particles.

步骤S3：将28份聚醋酸乙烯酯、5份导电炭黑、67份80目膨胀石墨和60份乙醇加入分散机中分散均匀，分散机转速1500转，分散30分钟，得到包覆涂料；Step S3: Add 28 parts of polyvinyl acetate, 5 parts of conductive carbon black, 67 parts of 80-mesh expanded graphite and 60 parts of ethanol to a disperser and disperse evenly. The disperser speed is 1500 rpm and the dispersion time is 30 minutes to obtain the coating.

步骤S4：按重量份计，将步骤S3得到的20kg导电聚合物泡沫颗粒加入搅拌桶中，随后加入30kg包覆涂料并搅拌得到第二混合物，搅拌速度80转/分钟，并将第二混合物加入风干设备中干燥，主轴破碎电机设置30转/分钟，干燥破碎20分钟，过筛得到含膨胀石墨复合树脂泡沫颗粒；Step S4: By weight, add 20kg of conductive polymer foam particles obtained in step S3 to a mixing tank, then add 30kg of coating material and stir to obtain a second mixture. The stirring speed is 80 rpm. The second mixture is then added to a drying device for drying. The main shaft crushing motor is set to 30 rpm. The drying and crushing process takes 20 minutes. The mixture is then sieved to obtain foam particles containing expanded graphite composite resin.

步骤S5：按体积份计，将步骤S3得到的80L导电聚合物泡沫颗粒和20L含膨胀石墨复合树脂泡沫颗粒混合得到第三混合物，随后将第三混合物成型得到500高角锥吸波材料。Step S5: By volume, mix 80L of conductive polymer foam particles and 20L of expanded graphite composite resin foam particles obtained in step S3 to obtain a third mixture, and then mold the third mixture to obtain a 500 high-angle pyramidal microwave absorbing material.

实施例5Example 5

一种高阻燃含膨胀石墨聚合物泡沫吸波材料的制备方法，包括如下步骤：A method for preparing a highly flame-retardant microwave absorbing material containing expanded graphite polymer foam includes the following steps:

步骤S1：按重量份计，将62.9份聚丙烯、25份导电炭黑、2份PE蜡、0.1份硼酸锌、8份包覆红磷混合均匀得到第一混合物，随后将第一混合物用密炼机混合后通过双螺杆挤出机挤出，双螺杆挤出机共有十一段，挤出温度依次为：第一段140°、第二段150°、第三段165°、第四段175°、第五段180°第六段185°、第七段192℃、第八段185°、第九段192°、第十段185°、第十一段192°，模头210°，得到0.3-2mg聚丙烯树脂；Step S1: By weight, 62.9 parts of polypropylene, 25 parts of conductive carbon black, 2 parts of PE wax, 0.1 parts of zinc borate, and 8 parts of coated red phosphorus are mixed evenly to obtain a first mixture. Then, the first mixture is mixed in an internal mixer and extruded through a twin-screw extruder. The twin-screw extruder has eleven stages, and the extrusion temperatures are as follows: stage 1 140°C, stage 2 150°C, stage 3 165°C, stage 4 175°C, stage 5 180°C, stage 6 185°C, stage 7 192°C, stage 8 185°C, stage 9 192°C, stage 10 185°C, stage 11 192°C, and the die is 210°C, to obtain 0.3-2 mg of polypropylene resin.

步骤S2：将步骤S1得到的聚丙烯树脂加入高压反应釜，向高压反应釜中加入所投入聚丙烯树脂重量2倍的水和所加入水重量3％的十二烷基苯磺酸钠，开启搅拌，加热并通入二氧化碳，压力为3.5mpa，反应釜温度为140℃，放出物料发泡、清洗、烘干制得密度为45kg/m3的聚丙烯泡沫颗粒，得到导电聚合物泡沫颗粒；Step S2: Add the polypropylene resin obtained in step S1 to a high-pressure reactor. Add water with a weight of 2 times that of the added polypropylene resin and sodium dodecylbenzenesulfonate with a weight of 3% of the added water to the high-pressure reactor. Start stirring, heat and introduce carbon dioxide. The pressure is 3.5 MPa and the reactor temperature is 140°C. Release the material, foam, wash and dry to obtain polypropylene foam particles with a density of 45 kg/ m3 , and obtain conductive polymer foam particles.

步骤S3：按重量份计，将28份聚醋酸乙烯酯、5份导电炭黑、67份80目膨胀石墨和60份乙醇加入分散机中分散均匀，分散机转速1500转，分散30分钟，得到包覆涂料；Step S3: By weight, add 28 parts of polyvinyl acetate, 5 parts of conductive carbon black, 67 parts of 80-mesh expanded graphite and 60 parts of ethanol to a disperser and disperse evenly. The disperser speed is 1500 rpm and the dispersion time is 30 minutes to obtain the coating.

步骤S4：按重量份计，将步骤S3得到的20kg导电聚合物泡沫颗粒加入搅拌桶中，随后加入30kg包覆涂料并搅拌得到第二混合物，搅拌速度80转/分钟，并将第二混合物加入风干设备中干燥，主轴破碎电机设置30转/分钟，干燥破碎20分钟，过筛得到含膨胀石墨复合树脂泡沫颗粒；Step S4: By weight, add 20kg of conductive polymer foam particles obtained in step S3 to a mixing tank, then add 30kg of coating material and stir to obtain a second mixture. The stirring speed is 80 rpm. The second mixture is then added to a drying device for drying. The main shaft crushing motor is set to 30 rpm. The drying and crushing process takes 20 minutes. The mixture is then sieved to obtain foam particles containing expanded graphite composite resin.

步骤S5：按体积份计，将步骤S3得到的90L导电聚合物泡沫颗粒和10L含膨胀石墨复合树脂泡沫颗粒混合得到第三混合物，随后将第三混合物成型得到500高角锥吸波材料。Step S5: By volume, mix the 90L conductive polymer foam particles and 10L expanded graphite composite resin foam particles obtained in step S3 to obtain a third mixture, and then mold the third mixture to obtain a 500 high-angle pyramidal microwave absorbing material.

实施例6Example 6

一种高阻燃含膨胀石墨聚合物泡沫吸波材料的制备方法，包括如下步骤：A method for preparing a highly flame-retardant microwave absorbing material containing expanded graphite polymer foam includes the following steps:

步骤S1：按重量份计，将62.9份聚丙烯、25份导电炭黑、2份PE蜡、0.1 份硼酸锌、8份包覆红磷混合均匀得到第一混合物，随后将第一混合物用密炼机混合后通过双螺杆挤出机挤出，双螺杆挤出机共有十一段，挤出温度依次为：第一段140°、第二段150°、第三段165°、第四段175°、第五段180°第六段185°、第七段192℃、第八段185°、第九段192°、第十段185°、第十一段192°，模头210°，得到0.3-2mg聚丙烯树脂；Step S1: By weight, combine 62.9 parts polypropylene, 25 parts conductive carbon black, 2 parts PE wax, and 0.1 parts... One part zinc borate and eight parts coated red phosphorus were mixed evenly to obtain a first mixture. The first mixture was then mixed in an internal mixer and extruded through a twin-screw extruder. The twin-screw extruder has eleven sections, and the extrusion temperatures are as follows: section 1 140°, section 2 150°, section 3 165°, section 4 175°, section 5 180°, section 6 185°, section 7 192°, section 8 185°, section 9 192°, section 10 185°, section 11 192°, and the die is 210°, to obtain 0.3-2 mg of polypropylene resin.

步骤S2：将步骤S1得到的聚丙烯树脂加入高压反应釜，向高压反应釜中加入所投入聚丙烯树脂重量2倍的水和所加入水重量3％的十二烷基苯磺酸钠，开启搅拌，加热并通入二氧化碳，压力为3.5mpa，反应釜温度为140℃，放出物料发泡、清洗、烘干制得密度为45kg/m3的聚丙烯泡沫颗粒，得到导电聚合物泡沫颗粒；Step S2: Add the polypropylene resin obtained in step S1 to a high-pressure reactor. Add water with a weight of 2 times that of the added polypropylene resin and sodium dodecylbenzenesulfonate with a weight of 3% of the added water to the high-pressure reactor. Start stirring, heat and introduce carbon dioxide. The pressure is 3.5 MPa and the reactor temperature is 140°C. Release the material, foam, wash and dry to obtain polypropylene foam particles with a density of 45 kg/ m3 , and obtain conductive polymer foam particles.

步骤S3：按重量份计，将28份聚醋酸乙烯酯、5份导电炭黑、67份80目膨胀石墨和60份乙醇加入分散机中分散均匀，分散机转速1500转，分散30分钟，得到包覆涂料；Step S3: By weight, add 28 parts of polyvinyl acetate, 5 parts of conductive carbon black, 67 parts of 80-mesh expanded graphite and 60 parts of ethanol to a disperser and disperse evenly. The disperser speed is 1500 rpm and the dispersion time is 30 minutes to obtain the coating.

步骤S4：按重量份计，将步骤S3得到的20kg导电聚合物泡沫颗粒加入搅拌桶中，随后加入30kg包覆涂料并搅拌得到第二混合物，搅拌速度80转/分钟，并将第二混合物加入风干设备中干燥，主轴破碎电机设置30转/分钟，干燥破碎20分钟，过筛得到含膨胀石墨复合树脂泡沫颗粒；Step S4: By weight, add 20kg of conductive polymer foam particles obtained in step S3 to a mixing tank, then add 30kg of coating material and stir to obtain a second mixture. The stirring speed is 80 rpm. The second mixture is then added to a drying device for drying. The main shaft crushing motor is set to 30 rpm. The drying and crushing process takes 20 minutes. The mixture is then sieved to obtain foam particles containing expanded graphite composite resin.

步骤S5：按体积份计，将步骤S3得到的40L导电聚合物泡沫颗粒和60L含膨胀石墨复合树脂泡沫颗粒混合得到第三混合物，随后将第三混合物成型得到500高角锥吸波材料。Step S5: By volume, the 40L conductive polymer foam particles and 60L expanded graphite composite resin foam particles obtained in step S3 are mixed to obtain a third mixture, and then the third mixture is molded to obtain a 500 high-angle pyramidal microwave absorbing material.

实施例7Example 7

一种高阻燃含膨胀石墨聚合物泡沫吸波材料的制备方法，包括如下步骤：A method for preparing a highly flame-retardant microwave absorbing material containing expanded graphite polymer foam includes the following steps:

步骤S1：按重量份计，将62.9份聚丙烯、25份导电炭黑、2份PE蜡、0.1份硼酸锌、8份包覆红磷混合均匀得到第一混合物，随后将第一混合物用密炼机混合后通过双螺杆挤出机挤出，双螺杆挤出机共有十一段，挤出温度依次为：第一段140°、第二段150°、第三段165°、第四段175°、第五段180°第六段185°、第七段192℃、第八段185°、第九段192°、第十段185°、第十一段192°，模头210°，得到0.3-2mg聚丙烯树脂；Step S1: By weight, 62.9 parts of polypropylene, 25 parts of conductive carbon black, 2 parts of PE wax, 0.1 parts of zinc borate, and 8 parts of coated red phosphorus are mixed evenly to obtain a first mixture. Then, the first mixture is mixed in an internal mixer and extruded through a twin-screw extruder. The twin-screw extruder has eleven stages, and the extrusion temperatures are as follows: stage 1 140°C, stage 2 150°C, stage 3 165°C, stage 4 175°C, stage 5 180°C, stage 6 185°C, stage 7 192°C, stage 8 185°C, stage 9 192°C, stage 10 185°C, stage 11 192°C, and the die is 210°C, to obtain 0.3-2 mg of polypropylene resin.

步骤S2：将步骤S1得到的聚丙烯树脂加入高压反应釜，向高压反应釜中加入所投入聚丙烯树脂重量2倍的水和所加入水重量3％的十二烷基苯磺酸钠，开启搅拌，加热并通入二氧化碳，压力为3.5mpa，反应釜温度为140℃，放出物料发泡、清洗、烘干制得密度为45kg/m3的聚丙烯泡沫颗粒，得到导电聚合物泡沫颗粒；Step S2: Add the polypropylene resin obtained in step S1 to a high-pressure reactor. Add water with a weight of 2 times that of the added polypropylene resin and sodium dodecylbenzenesulfonate with a weight of 3% of the added water to the high-pressure reactor. Start stirring, heat and introduce carbon dioxide. The pressure is 3.5 MPa and the reactor temperature is 140°C. Release the material, foam, wash and dry to obtain polypropylene foam particles with a density of 45 kg/ m3 , and obtain conductive polymer foam particles.

步骤S3：按重量份计，将28份聚醋酸乙烯酯、5份导电炭黑、67份80目膨胀石墨和60份乙醇加入分散机中分散均匀，分散机转速1500转，分散30分钟，得到包覆涂料；Step S3: By weight, add 28 parts of polyvinyl acetate, 5 parts of conductive carbon black, 67 parts of 80-mesh expanded graphite and 60 parts of ethanol to a disperser and disperse evenly. The disperser speed is 1500 rpm and the dispersion time is 30 minutes to obtain the coating.

步骤S4：按重量份计，将步骤S3得到的20kg导电聚合物泡沫颗粒加入搅拌桶中，随后加入30kg包覆涂料并搅拌得到第二混合物，搅拌速度80转/分钟，并将第二混合物加入风干设备中干燥，主轴破碎电机设置30转/分钟，干燥破 碎20分钟，过筛得到含膨胀石墨复合树脂泡沫颗粒；Step S4: By weight, add 20 kg of conductive polymer foam particles obtained in step S3 to a mixing tank, then add 30 kg of coating material and stir to obtain a second mixture at a stirring speed of 80 rpm. The second mixture is then added to a drying device for drying, with the main shaft crushing motor set to 30 rpm. Crumble for 20 minutes and sieve to obtain foam particles containing expanded graphite composite resin;

步骤S5：将步骤S4得到的100L含膨胀石墨复合树脂泡沫颗粒成型得到500高角锥吸波材料。Step S5: The 100L expanded graphite composite resin foam particles obtained in step S4 are molded into a 500 high-angle cone microwave absorbing material.

实施例8Example 8

一种高阻燃含膨胀石墨聚合物泡沫吸波材料的制备方法，包括如下步骤：A method for preparing a highly flame-retardant microwave absorbing material containing expanded graphite polymer foam includes the following steps:

步骤S1：按重量份计，将62.9份聚丙烯、25份导电炭黑、2份PE蜡、0.1份硼酸锌、8份聚磷酸铵混合均匀得到第一混合物，随后将第一混合物用密炼机混合后通过双螺杆挤出机挤出，双螺杆挤出机共有十一段，挤出温度依次为：第一段140°、第二段150°、第三段165°、第四段175°、第五段180°第六段185°、第七段192℃、第八段185°、第九段192°、第十段185°、第十一段192°，模头210°，得到0.3-2mg聚丙烯树脂；Step S1: By weight, 62.9 parts of polypropylene, 25 parts of conductive carbon black, 2 parts of PE wax, 0.1 parts of zinc borate, and 8 parts of ammonium polyphosphate are mixed evenly to obtain a first mixture. Then, the first mixture is mixed in an internal mixer and extruded through a twin-screw extruder. The twin-screw extruder has eleven stages, and the extrusion temperatures are as follows: stage 1 140°C, stage 2 150°C, stage 3 165°C, stage 4 175°C, stage 5 180°C, stage 6 185°C, stage 7 192°C, stage 8 185°C, stage 9 192°C, stage 10 185°C, stage 11 192°C, and the die is 210°C, to obtain 0.3-2 mg of polypropylene resin.

步骤S2：将步骤S1得到的聚丙烯树脂加入高压反应釜，向高压反应釜中加入所投入聚丙烯树脂重量2倍的水和所加入水重量3％的十二烷基苯磺酸钠，开启搅拌，加热并通入二氧化碳，压力为3.5mpa，反应釜温度为140℃，放出物料发泡、清洗、烘干制得密度为45kg/m3的聚丙烯泡沫颗粒，得到导电聚合物泡沫颗粒；Step S2: Add the polypropylene resin obtained in step S1 to a high-pressure reactor. Add water with a weight of 2 times that of the added polypropylene resin and sodium dodecylbenzenesulfonate with a weight of 3% of the added water to the high-pressure reactor. Start stirring, heat and introduce carbon dioxide. The pressure is 3.5 MPa and the reactor temperature is 140°C. Release the material, foam, wash and dry to obtain polypropylene foam particles with a density of 45 kg/ m3 , and obtain conductive polymer foam particles.

步骤S3：按重量份计，将28份聚醋酸乙烯酯、5份导电炭黑、67份80目膨胀石墨和60份乙醇加入分散机中分散均匀，分散机转速1500转，分散30分钟，得到包覆涂料；Step S3: By weight, add 28 parts of polyvinyl acetate, 5 parts of conductive carbon black, 67 parts of 80-mesh expanded graphite and 60 parts of ethanol to a disperser and disperse evenly. The disperser speed is 1500 rpm and the dispersion time is 30 minutes to obtain the coating.

步骤S4：按重量份计，将步骤S3得到的20kg导电聚合物泡沫颗粒加入搅拌桶中，随后加入30kg包覆涂料并搅拌得到第二混合物，搅拌速度80转/分钟，并将第二混合物加入风干设备中干燥，主轴破碎电机设置30转/分钟，干燥破碎20分钟，过筛得到含膨胀石墨复合树脂泡沫颗粒；Step S4: By weight, add 20kg of conductive polymer foam particles obtained in step S3 to a mixing tank, then add 30kg of coating material and stir to obtain a second mixture. The stirring speed is 80 rpm. The second mixture is then added to a drying device for drying. The main shaft crushing motor is set to 30 rpm. The drying and crushing process takes 20 minutes. The mixture is then sieved to obtain foam particles containing expanded graphite composite resin.

步骤S5：按体积份计，将步骤S3得到的50L导电聚合物泡沫颗粒和50L含膨胀石墨复合树脂泡沫颗粒混合得到第三混合物，随后将第三混合物成型得到500高角锥吸波材料。Step S5: By volume, the 50L conductive polymer foam particles and 50L expanded graphite composite resin foam particles obtained in step S3 are mixed to obtain a third mixture, and then the third mixture is molded to obtain a 500 high-angle pyramidal microwave absorbing material.

实施例9Example 9

一种高阻燃含膨胀石墨聚合物泡沫吸波材料的制备方法，包括如下步骤：A method for preparing a highly flame-retardant microwave absorbing material containing expanded graphite polymer foam includes the following steps:

步骤S1：按重量份计，将62.9份聚丙烯、25份导电炭黑、2份PE蜡、0.1份硼酸锌、8份包覆红磷混合均匀得到第一混合物，随后将第一混合物用密炼机混合后通过双螺杆挤出机挤出，双螺杆挤出机共有十一段，挤出温度依次为：第一段140°、第二段150°、第三段165°、第四段175°、第五段180°第六段185°、第七段192℃、第八段185°、第九段192°、第十段185°、第十一段192°，模头210°，得到0.3-2mg聚丙烯树脂；Step S1: By weight, 62.9 parts of polypropylene, 25 parts of conductive carbon black, 2 parts of PE wax, 0.1 parts of zinc borate, and 8 parts of coated red phosphorus are mixed evenly to obtain a first mixture. Then, the first mixture is mixed in an internal mixer and extruded through a twin-screw extruder. The twin-screw extruder has eleven stages, and the extrusion temperatures are as follows: stage 1 140°C, stage 2 150°C, stage 3 165°C, stage 4 175°C, stage 5 180°C, stage 6 185°C, stage 7 192°C, stage 8 185°C, stage 9 192°C, stage 10 185°C, stage 11 192°C, and the die is 210°C, to obtain 0.3-2 mg of polypropylene resin.

步骤S2：将步骤S1得到的聚丙烯树脂加入高压反应釜，向高压反应釜中加入所投入聚丙烯树脂重量2倍的水和所加入水重量3％的十二烷基苯磺酸钠，开启搅拌，加热并通入二氧化碳，压力为3.5mpa，反应釜温度为140℃，放出物料发泡、清洗、烘干制得密度为45kg/m3的聚丙烯泡沫颗粒，得到导电聚合物泡沫颗粒； Step S2: Add the polypropylene resin obtained in step S1 to a high-pressure reactor. Add water with a weight of 2 times that of the added polypropylene resin and sodium dodecylbenzenesulfonate with a weight of 3% of the added water to the high-pressure reactor. Start stirring, heat and introduce carbon dioxide. The pressure is 3.5 MPa and the reactor temperature is 140°C. Release the material, foam, wash and dry to obtain polypropylene foam particles with a density of 45 kg/ m3 , and obtain conductive polymer foam particles.

步骤S3：按重量份计，将步骤S2的99份导电聚合物泡沫颗粒与1份附着力促进剂混合加入风干设备中干燥，得到复合泡沫颗粒；Step S3: By weight, mix 99 parts of conductive polymer foam particles from step S2 with 1 part of adhesion promoter and add them to a drying equipment to dry, thereby obtaining composite foam particles.

步骤S4：按重量份计，将28份聚醋酸乙烯酯、5份导电炭黑、67份80目膨胀石墨和60份乙醇加入分散机中分散均匀，分散机转速1500转，分散30分钟，得到包覆涂料；Step S4: By weight, add 28 parts of polyvinyl acetate, 5 parts of conductive carbon black, 67 parts of 80-mesh expanded graphite and 60 parts of ethanol to a disperser and disperse evenly. The disperser speed is 1500 rpm and the dispersion time is 30 minutes to obtain the coating.

步骤S5：按重量份计，将步骤S3得到的20kg复合泡沫颗粒加入搅拌桶中，随后加入30kg包覆涂料并搅拌得到第二混合物，搅拌速度80转/分钟，并将第二混合物加入风干设备中干燥，主轴破碎电机设置30转/分钟，干燥破碎20分钟，过筛得到含膨胀石墨复合树脂泡沫颗粒；Step S5: By weight, add 20kg of composite foam particles obtained in step S3 to a mixing tank, then add 30kg of coating material and stir to obtain a second mixture. The stirring speed is 80 rpm. The second mixture is then added to a drying device for drying. The main shaft crushing motor is set to 30 rpm. The drying and crushing process takes 20 minutes. The mixture is then sieved to obtain foam particles containing expanded graphite composite resin.

步骤S6：将步骤S5得到的100L含膨胀石墨复合树脂泡沫颗粒成型得到500高角锥吸波材料。Step S6: The 100L expanded graphite composite resin foam particles obtained in step S5 are molded into a 500 high-angle cone microwave absorbing material.

对比例1Comparative Example 1

一种高阻燃含膨胀石墨聚合物泡沫吸波材料的制备方法，包括如下步骤：A method for preparing a highly flame-retardant microwave absorbing material containing expanded graphite polymer foam includes the following steps:

步骤S1：按重量份计，将64.9份聚丙烯、25份导电炭黑、2份PE蜡、0.1份硼酸锌、8份包覆红磷混合均匀得到第一混合物，随后将第一混合物用密炼机混合后通过双螺杆挤出机挤出，双螺杆挤出机共有十一段，挤出温度依次为：第一段140°、第二段150°、第三段165°、第四段175°、第五段180°、第六段185°、第七段192℃、第八段185°、第九段192°、第十段185°、第十一段192°，模头210°，得到0.3-2mg聚丙烯树脂；Step S1: By weight, 64.9 parts of polypropylene, 25 parts of conductive carbon black, 2 parts of PE wax, 0.1 parts of zinc borate, and 8 parts of coated red phosphorus are mixed evenly to obtain a first mixture. Then, the first mixture is mixed in an internal mixer and extruded through a twin-screw extruder. The twin-screw extruder has eleven stages, and the extrusion temperatures are as follows: stage 1 140°C, stage 2 150°C, stage 3 165°C, stage 4 175°C, stage 5 180°C, stage 6 185°C, stage 7 192°C, stage 8 185°C, stage 9 192°C, stage 10 185°C, stage 11 192°C, and die 210°C, to obtain 0.3-2 mg of polypropylene resin.

步骤S2：将聚丙烯树脂加入高压反应釜，向高压反应釜中加入所投入聚丙烯树脂重量2倍的水和所加入水重量3％的十二烷基苯磺酸钠，开启搅拌，加热并通入二氧化碳，压力为3.5mpa，反应釜温度为140℃，放出物料发泡、清洗、烘干制得密度为45kg/m3的导电聚丙烯泡沫颗粒；Step S2: Add polypropylene resin to a high-pressure reactor, add water equal to twice the weight of the added polypropylene resin and sodium dodecylbenzenesulfonate equal to 3% of the weight of the added water to the high-pressure reactor, start stirring, heat and introduce carbon dioxide, the pressure is 3.5 MPa, the reactor temperature is 140℃, release the material to foam, wash and dry to obtain conductive polypropylene foam particles with a density of 45 kg/ m3 .

步骤S3：将100L导电聚丙烯泡沫颗粒成型得到500高吸波角锥吸波材料。Step S3: 100L of conductive polypropylene foam particles are molded to obtain 500 high-absorption cone microwave absorbing material.

对比例2Comparative Example 2

一种高阻燃含膨胀石墨聚合物泡沫吸波材料的制备方法，包括如下步骤：A method for preparing a highly flame-retardant microwave absorbing material containing expanded graphite polymer foam includes the following steps:

步骤S1：按重量份计，将70.9份聚丙烯、25份导电炭黑、2份PE蜡、0.1份硼酸锌、混合均匀得到第一混合物，随后将第一混合物用密炼机混合后通过双螺杆挤出机挤出，双螺杆挤出机共有十一段，挤出温度依次为：第一段140°、第二段150°、第三段165°、第四段175°、第五段180°第六段185°、第七段192℃、第八段185°、第九段192°、第十段185°、第十一段192°，模头210°，得到0.3-2mg聚丙烯树脂；Step S1: By weight, 70.9 parts polypropylene, 25 parts conductive carbon black, 2 parts PE wax, and 0.1 parts zinc borate are mixed evenly to obtain a first mixture. The first mixture is then mixed in an internal mixer and extruded through a twin-screw extruder. The twin-screw extruder has eleven stages, and the extrusion temperatures are as follows: stage 1 140°C, stage 2 150°C, stage 3 165°C, stage 4 175°C, stage 5 180°C, stage 6 185°C, stage 7 192°C, stage 8 185°C, stage 9 192°C, stage 10 185°C, stage 11 192°C, and die 210°C, to obtain 0.3-2 mg of polypropylene resin.

步骤S2：将步骤S1得到的聚丙烯树脂加入高压反应釜，向高压反应釜中加入所投入聚丙烯树脂重量2倍的水和所加入水重量3％的十二烷基苯磺酸钠，开启搅拌，加热并通入二氧化碳，压力为3.5mpa，反应釜温度为140℃，放出物料发泡、清洗、烘干制得密度为45kg/m3的聚丙烯泡沫颗粒，得到导电聚合物泡沫颗粒；Step S2: Add the polypropylene resin obtained in step S1 to a high-pressure reactor. Add water with a weight of 2 times that of the added polypropylene resin and sodium dodecylbenzenesulfonate with a weight of 3% of the added water to the high-pressure reactor. Start stirring, heat and introduce carbon dioxide. The pressure is 3.5 MPa and the reactor temperature is 140°C. Release the material, foam, wash and dry to obtain polypropylene foam particles with a density of 45 kg/ m3 , and obtain conductive polymer foam particles.

步骤S3：按重量份计，将28份聚醋酸乙烯酯、5份导电炭黑、67份80目膨胀石墨和60份乙醇加入分散机中分散均匀，分散机转速1500转，分散30分 钟，得到包覆涂料；Step S3: By weight, add 28 parts polyvinyl acetate, 5 parts conductive carbon black, 67 parts 80-mesh expanded graphite, and 60 parts ethanol to a disperser and disperse evenly at a speed of 1500 rpm for 30 minutes. The clock was coated with a coating.

步骤S4：按重量份计，将步骤S3得到的20kg导电聚合物泡沫颗粒加入搅拌桶中，随后加入30kg包覆涂料并搅拌得到第二混合物，搅拌速度80转/分钟，并将第二混合物加入风干设备中干燥，主轴破碎电机设置30转/分钟，干燥破碎20分钟，过筛得到含膨胀石墨复合树脂泡沫颗粒；Step S4: By weight, add 20kg of conductive polymer foam particles obtained in step S3 to a mixing tank, then add 30kg of coating material and stir to obtain a second mixture. The stirring speed is 80 rpm. The second mixture is then added to a drying device for drying. The main shaft crushing motor is set to 30 rpm. The drying and crushing process takes 20 minutes. The mixture is then sieved to obtain foam particles containing expanded graphite composite resin.

步骤S5：按体积份计，将步骤S3得到的50L导电聚合物泡沫颗粒和50L含膨胀石墨复合树脂泡沫颗粒混合得到第三混合物，随后将第三混合物成型得到500高角锥吸波材料。Step S5: By volume, the 50L conductive polymer foam particles and 50L expanded graphite composite resin foam particles obtained in step S3 are mixed to obtain a third mixture, and then the third mixture is molded to obtain a 500 high-angle pyramidal microwave absorbing material.

将实施例1-9和对比例1-2的吸波材料进行测试，测试结果如表1。The microwave absorbing materials of Examples 1-9 and Comparative Examples 1-2 were tested, and the test results are shown in Table 1.

表1
Table 1

由表1可知，对比例1为未添加膨胀石墨，只单独添加8％红磷阻燃剂，其测得氧指数为25，如再增加更多的红磷阻燃剂比例，对氧指数的提升并不大，如再添加更多的红磷超15％，反而对氧指数提升有相反的作用，由于红磷是特别易燃的材料；对挤出造粒工艺及设备具有安全隐患；对比例2为未添加红磷阻燃剂，制造不含红磷阻燃剂的发泡聚丙烯颗粒，经过测试发现不含红磷阻燃剂时其氧指数仅有24，其原因是没有红磷参与到聚合物燃烧时反应，在聚合物表面没有形成致密的且成膜的立体网状结构，氧气依然可以从膨胀石墨膨胀后的石墨蠕虫缝隙中进入，对提升氧指数帮助不是太明显。As shown in Table 1, Comparative Example 1, without the addition of expanded graphite and only with the addition of 8% red phosphorus flame retardant, had an oxygen index of 25. Increasing the proportion of red phosphorus flame retardant further did not significantly improve the oxygen index. Adding more than 15% red phosphorus had the opposite effect, as red phosphorus is a highly flammable material and poses a safety hazard to the extrusion granulation process and equipment. Comparative Example 2, without the addition of red phosphorus flame retardant, produced foamed polypropylene granules. Testing revealed that the oxygen index without red phosphorus flame retardant was only 24. This is because no red phosphorus participated in the polymer combustion reaction, and a dense, film-forming three-dimensional network structure was not formed on the polymer surface. Oxygen could still enter through the worm-like gaps in the expanded graphite, thus not significantly improving the oxygen index.

实施例1为含红磷阻燃剂聚丙烯树脂泡沫颗粒与含膨胀石墨复合树脂泡沫颗粒按照50:50，测试综合性能评估，其氧指数可以达到32.5，但是由于含膨 胀石墨复合树脂泡沫颗粒表面包覆一层涂层，由于涂层与聚丙烯泡沫相容性及附着力较弱，相当于含膨胀石墨复合树脂泡沫颗粒是夹杂在导电聚合物泡沫颗粒之间的，由于掺混过多，导致导电聚合物泡沫颗粒不能连续熔接，所以通过物理性能测试得知其，断裂伸长率为0.5％，通过后面的其他实施例可以得知；实施例7为单独含膨胀石墨复合树脂泡沫颗粒制成的吸波材料，氧指数可高达到33.5，由于胶黏剂与胶黏剂附着力好于胶黏剂与聚合物树脂表面附着力，所以实施例7机械性能好与多比例含膨胀石墨复合树脂泡沫颗粒掺混的机械性能；实施例8为用聚磷酸铵(APP)替换红磷阻燃剂，与实施例1作对比，由于APP磷含量较低，其对氧指数提升有一定帮助，但是通过测试得知，其提升氧指数的效果没有膨胀石墨和红磷阻燃剂复配效果好；Example 1 compares polypropylene resin foam particles containing red phosphorus flame retardant and composite resin foam particles containing expanded graphite in a 50:50 ratio. A comprehensive performance evaluation was conducted, and the oxygen index reached 32.5. However, due to the presence of expanded graphite... The surface of the expanded graphite composite resin foam particles is coated with a layer of coating. Due to the weak compatibility and adhesion between the coating and the polypropylene foam, it is equivalent to the expanded graphite composite resin foam particles being sandwiched between the conductive polymer foam particles. Due to excessive mixing, the conductive polymer foam particles cannot be continuously fused. Therefore, physical property tests show that its elongation at break is 0.5%, as can be seen from other examples later. Example 7 is a microwave absorbing material made solely from expanded graphite composite resin foam particles, with an oxygen index as high as 33.5. Since the adhesion between adhesives is better than the adhesion between adhesives and the surface of polymer resin, Example 7 has better mechanical properties than the mechanical properties of a mixture containing a large proportion of expanded graphite composite resin foam particles. Example 8 uses ammonium polyphosphate (APP) to replace red phosphorus flame retardant. Compared with Example 1, since APP has a lower phosphorus content, it helps to improve the oxygen index to some extent. However, tests show that its effect on improving the oxygen index is not as good as the effect of the combination of expanded graphite and red phosphorus flame retardant.

实施例9为在导电聚合物泡沫颗粒表面进行附着力促进剂处理后再进行包覆一层含膨胀石墨涂层，通过测试得知机械性能比实施例7全包覆含膨胀石墨涂层的机械性能有较大提升。Example 9 involved treating the surface of conductive polymer foam particles with an adhesion promoter and then coating it with a layer of expanded graphite. Tests showed that the mechanical properties were significantly improved compared to the fully coated expanded graphite layer in Example 7.

通过实施例5与对比例1对比，只需在导电聚合物泡沫颗粒混合20份含膨胀石墨复合树脂泡沫颗粒既可满足电磁波暗室工程技术规范(GB50826-2012)中要求氧指数大于28的要求，实施例7和实施例9更是能满足大多数客户实际使用要求氧指数大于32的需求。By comparing Example 5 with Comparative Example 1, it is found that mixing 20 parts of expanded graphite composite resin foam particles with conductive polymer foam particles can meet the requirement of an oxygen index greater than 28 in the Technical Specification for Electromagnetic Anechoic Chamber Engineering (GB50826-2012). Examples 7 and 9 can even meet the actual use requirements of most customers for an oxygen index greater than 32.

从图1可以看出，膨胀石墨均匀的附着在聚丙烯泡沫颗粒表面，图2为聚丙烯颗粒切开扫描电镜图，添加较少的成核剂可以提高泡孔的孔径，并能提高泡沫颗粒表面粗糙度，以助于提高附着力。As shown in Figure 1, expanded graphite is uniformly attached to the surface of polypropylene foam particles. Figure 2 is a scanning electron microscope image of a cut polypropylene particle. Adding less nucleating agent can increase the pore size of the foam and improve the surface roughness of the foam particles, thus helping to improve adhesion.

最后所应说明的是，以上具体实施方式仅用以说明本发明的技术方案而非限制，尽管参照实例对本发明进行了详细说明，本领域的普通技术人员应当理解，可以对本发明的技术方案进行修改或者等同替换，而不脱离本发明技术方案的精神和范围，其均应涵盖在本发明的权利要求范围当中。 Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims (10)

一种高阻燃含膨胀石墨聚合物泡沫吸波材料，其特征在于：按体积份计，包括导电聚合物泡沫颗粒0-90份，含膨胀石墨复合树脂泡沫颗粒10-100份。A highly flame-retardant wave-absorbing material containing expanded graphite polymer foam, characterized in that: by volume, it comprises 0-90 parts of conductive polymer foam particles and 10-100 parts of expanded graphite composite resin foam particles. 根据权利要求1所述的高阻燃含膨胀石墨聚合物泡沫吸波材料，其特征在于：按重量份计，所述含膨胀石墨复合树脂泡沫颗粒包括导电聚合物泡沫颗粒30-95份和包覆涂料5-70份，包覆涂料包括胶黏剂5-50份、导电剂1-30份、第一阻燃剂0-20份、膨胀石墨20-95份、溶剂13-300份。According to claim 1, the high flame-retardant polymer foam absorbing material containing expanded graphite is characterized in that, by weight, the expanded graphite composite resin foam particles comprise 30-95 parts of conductive polymer foam particles and 5-70 parts of coating material, wherein the coating material comprises 5-50 parts of adhesive, 1-30 parts of conductive agent, 0-20 parts of first flame retardant, 20-95 parts of expanded graphite, and 13-300 parts of solvent. 根据权利要求1或2所述的高阻燃含膨胀石墨聚合物泡沫吸波材料，其特征在于：所述导电聚合物泡沫颗粒选自聚丙烯泡沫颗粒和聚乙烯泡沫颗粒中的一种，所述聚丙烯泡沫颗粒或聚乙烯泡沫颗粒均包括至少一种聚丙烯树脂或聚乙烯树脂，按重量份计，每种所述聚丙烯树脂或聚乙烯树脂均包括以下组分：聚丙烯或聚乙烯45-95份、导电剂5-35份、分散剂1-10份、第一阻燃剂1-20份、成核剂0.1-1份。The high flame-retardant expanded graphite polymer foam absorbing material according to claim 1 or 2 is characterized in that: the conductive polymer foam particles are selected from one of polypropylene foam particles and polyethylene foam particles, and each of the polypropylene foam particles or polyethylene foam particles includes at least one polypropylene resin or polyethylene resin. By weight, each of the polypropylene resins or polyethylene resins includes the following components: 45-95 parts of polypropylene or polyethylene, 5-35 parts of conductive agent, 1-10 parts of dispersant, 1-20 parts of first flame retardant, and 0.1-1 parts of nucleating agent. 根据权利要求2或3所述的高阻燃含膨胀石墨聚合物泡沫吸波材料，其特征在于：所述导电剂选自炭黑、石墨、石墨烯、碳纳米管或金属粉末的一种或多种；所述第一阻燃剂选自包覆红磷、聚磷酸铵、磷酸二氢铝、季戊四醇磷酸酯、溴化聚苯乙烯中的一种或多种。The high flame-retardant expanded graphite polymer foam microwave absorbing material according to claim 2 or 3 is characterized in that: the conductive agent is selected from one or more of carbon black, graphite, graphene, carbon nanotubes or metal powder; the first flame retardant is selected from one or more of coated red phosphorus, ammonium polyphosphate, aluminum dihydrogen phosphate, pentaerythritol phosphate, and brominated polystyrene. 根据权利要求3所述的高阻燃含膨胀石墨聚合物泡沫吸波材料，其特征在于：所述分散剂选自PE蜡和磷酸三苯酯中的一种或两种。The high flame-retardant expanded graphite polymer foam microwave absorbing material according to claim 3 is characterized in that: the dispersant is selected from one or two of PE wax and triphenyl phosphate. 根据权利要求2所述的高阻燃含膨胀石墨聚合物泡沫吸波材料，其特征在于：所述胶黏剂选自酚醛、丙烯酸树脂、乙烯丙烯酸共聚物、聚醋酸乙烯酯、聚氨酯胶黏剂和有机硅树脂中的一种或多种。According to claim 2, the high flame-retardant expanded graphite polymer foam absorbing material is characterized in that: the adhesive is selected from one or more of phenolic resin, acrylic resin, ethylene-acrylic acid copolymer, polyvinyl acetate, polyurethane adhesive and silicone resin. 根据权利要求1或2所述的高阻燃含膨胀石墨聚合物泡沫吸波材料，其特征在于：所述导电聚合物泡沫颗粒外表面还包覆附着力促进剂，所述导电聚合物泡沫颗粒和附着力促进剂的质量比为80-99：1-20。The high flame-retardant expanded graphite polymer foam absorbing material according to claim 1 or 2 is characterized in that: the outer surface of the conductive polymer foam particles is further coated with an adhesion promoter, and the mass ratio of the conductive polymer foam particles to the adhesion promoter is 80-99:1-20. 根据权利要求7所述的高阻燃含膨胀石墨聚合物泡沫吸波材料，其特征在于：所述附着力促进剂为氯化聚丙烯溶液。The high flame-retardant expanded graphite polymer foam absorbing material according to claim 7 is characterized in that: the adhesion promoter is a chlorinated polypropylene solution. 一种高阻燃含膨胀石墨聚合物泡沫吸波材料的制备方法，其特征在于：包括如下步骤：A method for preparing a highly flame-retardant microwave absorbing material containing expanded graphite polymer foam, characterized by comprising the following steps: 步骤S1：按重量份计，将45-95份聚丙烯或聚乙烯、5-35份导电剂、1-10份分散剂，1-20份第一阻燃剂混合均匀得到第一混合物，随后将第一混合物用密炼机混合后通过双螺杆挤出机挤出得到至少一种0.3-2mg的聚丙烯树脂或聚乙烯树脂；Step S1: By weight, 45-95 parts of polypropylene or polyethylene, 5-35 parts of conductive agent, 1-10 parts of dispersant, and 1-20 parts of first flame retardant are mixed evenly to obtain a first mixture. Then, the first mixture is mixed in an internal mixer and extruded through a twin-screw extruder to obtain at least 0.3-2 mg of polypropylene resin or polyethylene resin. 步骤S2：将步骤S1的至少一种聚丙烯树脂或聚乙烯树脂加入高压反应釜，并向高压反应釜中加入水、表面活性剂，随后开启搅拌，加热并通入氮气或者二氧化碳，持续加热至聚丙烯树脂或聚乙烯树脂熔点时，放出物料发泡制得聚丙烯泡沫颗粒或聚乙烯泡沫颗粒，得到导电聚合物泡沫颗粒； Step S2: Add at least one polypropylene resin or polyethylene resin from step S1 to a high-pressure reactor, and add water and surfactant to the high-pressure reactor. Then start stirring, heat and introduce nitrogen or carbon dioxide. Continue heating until the melting point of the polypropylene resin or polyethylene resin is reached, and release the material to foam and obtain polypropylene foam particles or polyethylene foam particles, thus obtaining conductive polymer foam particles. 步骤S3：按重量份计，将5-50份胶黏剂、1-30份导电剂、1-30份第一阻燃剂、20-95份膨胀石墨和13-300份溶剂加入分散机中分散均匀，得到包覆涂料；Step S3: By weight, add 5-50 parts of adhesive, 1-30 parts of conductive agent, 1-30 parts of first flame retardant, 20-95 parts of expanded graphite and 13-300 parts of solvent to a disperser and disperse evenly to obtain a coating. 步骤S4：按重量份计，将步骤S3的30-95份导电聚合物泡沫颗粒加入搅拌桶中，随后加入S4的5-70份包覆涂料并搅拌得到第二混合物，并将第二混合物加入风干设备中干燥，过筛得到含膨胀石墨复合树脂泡沫颗粒；Step S4: By weight, add 30-95 parts of conductive polymer foam particles from step S3 to a mixing tank, then add 5-70 parts of coating material from S4 and stir to obtain a second mixture. Add the second mixture to a drying device to dry and sieve to obtain foam particles containing expanded graphite composite resin. 步骤S5：按体积份计，将0-90份导电聚合物泡沫颗粒和10-100份含膨胀石墨复合树脂泡沫颗粒混合得到第三混合物，随后将第三混合物成型得到吸波材料。Step S5: By volume, 0-90 parts of conductive polymer foam particles and 10-100 parts of expanded graphite composite resin foam particles are mixed to obtain a third mixture, and then the third mixture is molded to obtain a microwave absorbing material. 一种高阻燃含膨胀石墨聚合物泡沫吸波材料的制备方法，其特征在于：包括如下步骤：A method for preparing a highly flame-retardant microwave absorbing material containing expanded graphite polymer foam, characterized by comprising the following steps: 步骤S1：按重量份计，将45-95份聚丙烯或聚乙烯、5-35份导电剂、1-10份分散剂，1-20份第一阻燃剂混合均匀得到第一混合物，随后将第一混合物用密炼机混合后通过双螺杆挤出机挤出得到至少一种0.3-2mg的聚丙烯树脂或聚乙烯树脂；Step S1: By weight, 45-95 parts of polypropylene or polyethylene, 5-35 parts of conductive agent, 1-10 parts of dispersant, and 1-20 parts of first flame retardant are mixed evenly to obtain a first mixture. Then, the first mixture is mixed in an internal mixer and extruded through a twin-screw extruder to obtain at least 0.3-2 mg of polypropylene resin or polyethylene resin. 步骤S2：将步骤S1的至少一种聚丙烯树脂或聚乙烯树脂加入高压反应釜，并向高压反应釜中加入水、表面活性剂，随后开启搅拌，加热并通入氮气或者二氧化碳，持续加热至聚丙烯树脂或聚乙烯树脂熔点时，放出物料发泡制得聚丙烯泡沫颗粒、聚乙烯泡沫颗粒，得到导电聚合物泡沫颗粒；Step S2: Add at least one polypropylene resin or polyethylene resin from step S1 to a high-pressure reactor, and add water and surfactant to the high-pressure reactor. Then start stirring, heat and introduce nitrogen or carbon dioxide. Continue heating until the melting point of polypropylene resin or polyethylene resin is reached, and release the material to foam and obtain polypropylene foam particles and polyethylene foam particles, thus obtaining conductive polymer foam particles. 步骤S3：按重量份计，将步骤S2的80-99份导电聚合物泡沫颗粒与1-20份附着力促进剂混合加入风干设备中干燥，得到复合泡沫颗粒；Step S3: By weight, mix 80-99 parts of conductive polymer foam particles from step S2 with 1-20 parts of adhesion promoter and add them to an air-drying device to dry, thereby obtaining composite foam particles; 步骤S4：按重量份计，将5-50份胶黏剂、1-30份导电剂、1-30份第一阻燃剂、20-95份膨胀石墨和13-300份溶剂加入分散机中分散均匀，得到包覆涂料；Step S4: By weight, add 5-50 parts of adhesive, 1-30 parts of conductive agent, 1-30 parts of first flame retardant, 20-95 parts of expanded graphite and 13-300 parts of solvent to a disperser and disperse evenly to obtain a coating. 步骤S5：按重量份计，将步骤S3的30-95份复合泡沫颗粒加入搅拌桶中，随后加入S4的5-70份包覆涂料并搅拌得到第二混合物，并将第二混合物加入风干设备中干燥，过筛得到含膨胀石墨复合树脂泡沫颗粒；Step S5: By weight, add 30-95 parts of the composite foam particles from step S3 to a mixing tank, then add 5-70 parts of the coating material from S4 and stir to obtain a second mixture. Add the second mixture to a drying equipment to dry, and sieve to obtain foam particles containing expanded graphite composite resin. 步骤S6：按体积份计，将0-90份复合泡沫颗粒和10-100份含膨胀石墨复合树脂泡沫颗粒混合得到第三混合物，随后将第三混合物成型得到吸波材料。 Step S6: By volume, 0-90 parts of composite foam particles and 10-100 parts of expanded graphite composite resin foam particles are mixed to obtain a third mixture, and then the third mixture is molded to obtain a microwave absorbing material.
PCT/CN2024/097222 2024-05-31 2024-06-04 High flame-retardant polymer foam microwave-absorbing material containing expanded graphite and preparation method therefor Pending WO2025245910A1 (en)

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