CN113622217B - Magnetic paper base material and preparation method thereof - Google Patents

Magnetic paper base material and preparation method thereof Download PDF

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Publication number
CN113622217B
CN113622217B CN202010387569.3A CN202010387569A CN113622217B CN 113622217 B CN113622217 B CN 113622217B CN 202010387569 A CN202010387569 A CN 202010387569A CN 113622217 B CN113622217 B CN 113622217B
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magnetic
paper
base material
polymer
magnetic paper
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CN113622217A (en
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胡健
王宜
龙金
王浩
沈俊奕
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South China University of Technology SCUT
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South China University of Technology SCUT
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    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H13/00—Pulp or paper, comprising synthetic cellulose or non-cellulose fibres or web-forming material
    • D21H13/10—Organic non-cellulose fibres
    • D21H13/20—Organic non-cellulose fibres from macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
    • D21H13/26—Polyamides; Polyimides
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F11/00—Processes for making continuous lengths of paper, or of cardboard, or of wet web for fibre board production, on paper-making machines
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F13/00—Making discontinuous sheets of paper, pulpboard or cardboard, or of wet web, for fibreboard production
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H13/00—Pulp or paper, comprising synthetic cellulose or non-cellulose fibres or web-forming material
    • D21H13/10—Organic non-cellulose fibres
    • D21H13/20—Organic non-cellulose fibres from macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
    • D21H17/63—Inorganic compounds
    • D21H17/67—Water-insoluble compounds, e.g. fillers, pigments
    • D21H17/675—Oxides, hydroxides or carbonates
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
    • D21H17/63—Inorganic compounds
    • D21H17/67—Water-insoluble compounds, e.g. fillers, pigments
    • D21H17/68—Water-insoluble compounds, e.g. fillers, pigments siliceous, e.g. clays
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/032—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials
    • H01F1/04—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys
    • H01F1/06—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys in the form of particles, e.g. powder
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/032—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials
    • H01F1/10—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials non-metallic substances, e.g. ferrites, e.g. [(Ba,Sr)O(Fe2O3)6] ferrites with hexagonal structure
    • H01F1/11—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials non-metallic substances, e.g. ferrites, e.g. [(Ba,Sr)O(Fe2O3)6] ferrites with hexagonal structure in the form of particles

Abstract

The invention relates to a magnetic paper base material and a preparation method thereof. The material consists of magnetic precipitation pulp, high-performance polymer fiber and conductive fiber, wherein the magnetic precipitation pulp accounts for 100-10wt% of the magnetic paper base material, and preferably 100-50wt%; the high-performance polymer fiber accounts for 0-90wt%, preferably 0-50wt% of the magnetic paper base material; the weight percentage of the conductive fiber in the magnetic paper base material is 0-25wt%, preferably 0-5wt%. The material can effectively solve the problem that magnetic particles are easy to fall off, has stable electromagnetic performance, high absorptivity, light weight, corrosion resistance and excellent strength, and the prepared honeycomb material has excellent performance and is an advanced magnetic material.

Description

Magnetic paper base material and preparation method thereof
Technical Field
The invention relates to a magnetic paper base material and a preparation method thereof.
Background
The magnetic paper base material is prepared by taking high-performance synthetic fibers as a framework, mixing the high-performance synthetic fibers according to a certain proportion, adding magnetic particle substances as a wave-absorbing medium, and preparing paper by a wet forming method, wherein two problems need to be considered during design: 1) The electromagnetic wave needs to pass through the surface of the material as completely as possible, so that the reflection is reduced; 2) When electromagnetic waves enter the material, the energy of the electromagnetic waves is lost as much as possible, so that the interference of the electromagnetic waves is reduced. The honeycomb structural member is processed into a honeycomb structural member, and can well meet the requirements of structure and function integration, so that the honeycomb structural member has wide application prospect in the fields of aviation and aerospace. At present, according to the forming process and the bearing capacity, the coating type and the structural type can be divided into two categories.
The coating type wave-absorbing material is prepared by taking a high molecular solution, emulsion or liquid high polymer as a matrix and dispersing particles with electromagnetic loss as a wave-absorbing agent and other additional components in the matrix, and has the defects of narrow absorption band, large weight, low bonding strength, poor weather resistance and the like. The structural wave-absorbing material has the dual functions of bearing and absorbing waves and comprises a laminated plate type, a honeycomb sandwich type, a foam sandwich type and a fiber woven structure at present. However, the conventional wave-absorbing sandwich material, such as a honeycomb sandwich material, is mainly prepared by taking a paper honeycomb as a substrate and impregnating a glue solution doped with a wave-absorbing agent, and the preparation method has a complex process, and if the wave-absorbing agent needs to be uniformly dispersed in the glue solution, the uniform impregnation is often difficult to realize when the glue solution contains the wave-absorbing agent, so that the gradient control of electromagnetic parameters is difficult to realize, the optimization of impedance matching characteristics is not facilitated, and the broadband wave-absorbing effect is not ideal. In addition, the wave-absorbing sandwich material prepared by the method is easy to have the phenomenon of absorbent peeling after being used for a long time, pollutes the surrounding electromagnetic environment and influences the stability of the wave-absorbing performance of the wave-absorbing sandwich material.
U.S. Pat. No. 4,234,378 mentions the preparation of magnetic paper using barium ferrite powder or magnetic strontium ferrite powder, which is added to synthetic resin such as SBR/NBR polyvinyl acetate, polyacrylate, which contains water-soluble or emulsifiable organic polymer electrolyte such as polyamine polyethyleneimine. Although this method increases the uniformity of ferrite dispersion in the resin, it still cannot avoid the risk of high temperature and falling off.
Patent No. CN1125797A discloses a method for making magnetic paper, in which magnetic material is attached to the inside or surface of the paper, a proper amount of powdered substance of ferrimagnetic material is added to the paper pulp, and then the paper is made into magnetic paper, or a layer of magnetic material powder is directly sprayed on the surface of the paper, and then the magnetic paper is made by magnetic treatment.
Patent No. CN105401484A proposes that absorption type electromagnetic shielding paper is prepared by adding composite wave absorbent components such as nickel powder, silicon carbide, ferrite, glass fiber and the like into plant fiber. However, the strength and tolerance of the plant fiber are poor, so that the material cannot be used in a harsher environment, and the use environment of the material is limited.
Patent No. CN107418512A discloses a method for preparing an ultrathin paper-based wave-absorbing material, which comprises using a multi-walled carbon nanotube as a carrier, acidifying with concentrated nitric acid to generate oxygen-containing groups on the surface of the carbon nanotube, uniformly embedding cobalt-nickel ferrite nanoparticles on the carbon nanotube under the action of electrostatic attraction between metal ions and the oxygen-containing groups to generate a cobalt-nickel ferrite carbon nanotube with good wave-absorbing effect, and finally manufacturing the cobalt-nickel ferrite carbon nanotube and recycled paper fibers to obtain the ultrathin paper-based wave-absorbing material. The method has complicated process and limited surface area of the carbon nano tube, and the performance of the carbon nano tube can be influenced by excessive acidification treatment, so that the strength of the whole material is low.
Chinese patent CN104404814A mentions that the paper with wave absorbing performance is made by mixing the fiber wave absorbing agent and wave-transmitting fiber through the paper making process, wherein the paper also contains the granular or irregular-shaped wave absorbing agent, such as metal powder, carbon black, ceramic powder, ferrite powder, hollow microspheres, etc. Because the density difference between the wave absorbing agent and the wave-transmitting fiber is large, the wave absorbing agent and the wave-transmitting fiber are not uniformly dispersed in the dispersing process, and the magnetic particles have small sizes and large density, the retention rate is low because the magnetic particles easily penetrate through meshes in the papermaking process, and the exposed magnetic particles are oxidized and rusted due to contact with air, so that the wave absorbing performance of the material is influenced.
Disclosure of Invention
In order to solve the defects of the prior art, the invention provides a magnetic paper base material with designable electromagnetic performance and a preparation method thereof.
The invention is realized by the following technical scheme.
In one aspect, the invention provides a magnetic paper base material, which is composed of magnetic precipitation pulp, high-performance polymer fiber and conductive fiber, wherein the magnetic precipitation pulp accounts for 100-10wt%, preferably 100-50wt% of the magnetic paper base material; the high-performance polymer fiber accounts for 0-90wt%, preferably 0-50wt% of the magnetic paper base material; the weight percentage of the conductive fibers in the magnetic paper base material is 0-25wt%, preferably 0-5wt%;
preferably, the magnetic precipitation pulp is prepared by a precipitation process of magnetic particles and polymer solution;
preferably, the magnetic particles are added in an amount of 1 to 2000wt%, preferably 50 to 1000wt%, more preferably 100 to 400wt% of the weight of the polymer in the polymer solution.
Preferably, the polymer in the polymer solution is a polymer with low dielectric loss, and is selected from one or more of high-performance polymers such as poly-p-Phenylene Benzobisoxazole (PBO), aramid fiber and polyimide, and is preferably poly-p-Phenylene Benzobisoxazole (PBO);
preferably, the beating degree of the magnetic precipitation pulp is 32-80 ° SR, preferably 40-80 ° SR.
Preferably, the magnetic particles are selected from one or more of carbonyl iron, ferrite, iron-silicon-aluminum, iron, cobalt, nickel and the like.
Preferably, the magnetic particles may be in the shape of flakes, wherein the size range is: a thickness of less than 20 μm, preferably less than 1 μm; the length and width are 20-300 μm, preferably 150-200 μm; or spherical, wherein the diameter range is: 5nm-200 μm, preferably 10nm-20 μm; it may also be fibrous, wherein the diameter ranges are: 10nm to 150 μm, a length of 150 μm to 6mm, preferably in the range of 10nm to 30 μm in diameter, 150 μm to 3mm in length and various irregular shapes.
Preferably, the high performance polymer fibers are selected from one or more of PBO fibers, aramid fibers and polyimide fibers.
Preferably, the conductive fibers are selected from one or more of carbon fibers and nickel-plated carbon fibers; preferably, the length of the conductive fibres is between 0.5mm and 15mm, preferably between 3mm and 9mm.
In another aspect, the present invention provides a method for preparing the magnetic paper-based material, including the steps of:
(1) Preparing polymer precipitation pulp containing magnetic particles, namely the magnetic precipitation pulp, from the magnetic particles and the polymer solution through a precipitation process; the magnetic particles are added during the precipitation of the polymer solution, which is carried out by conventional preparation methods, as described in detail in, for example, morgan patent No. 2,999,788.
(2) And (2) adding the magnetic precipitation pulp, the high-performance polymer fiber and the conductive fiber prepared in the step (1) into a fluffer according to a ratio for fluffing, then using a sheet machine or forming a single layer or multiple layers on a forming wire of the paper machine, dehydrating, forming and squeezing, and finally drying to constant weight to prepare the magnetic paper base material.
Preferably, in the step (2), the magnetic precipitation pulp, the high-performance polymer fiber and the conductive fiber prepared in the step (1) are added into a fluffer according to a ratio to be fluffed, then a plurality of layers, preferably 3-4 layers, are formed on a forming wire of the paper machine by using a sheet machine, and are dewatered, formed and pressed, and finally dried to constant weight, so that the magnetic paper base material is prepared.
Preferably, when the multilayer forming is performed in the step (2), in the upper and lower surface layers, the magnetic precipitation pulp accounts for 0-10wt%, preferably 0-3wt% of the magnetic paper base material, the conductive fiber accounts for less than 3wt% of the magnetic paper base material, and the balance is high-performance polymer fiber; in the intermediate layer, the weight percentage of the magnetic precipitation pulp in the magnetic paper base material is 10-100wt%; the weight percentage of the conductive fiber in the magnetic paper base material is 0-20wt%, and the rest is high-performance polymer fiber.
The invention has the following advantages:
the invention adopts carbonyl iron, ferrite, iron-silicon-aluminum, iron, cobalt, nickel and other magnetic particles as wave absorbing agents, has the advantages of high magnetization intensity, thermal mechanical stability and the like, and the prepared material has the characteristics of high absorptivity, thin matching thickness and the like.
The polymer precipitation pulp adopted by the invention has excellent performances such as low density, high strength, high modulus, high heat resistance, good dielectric property, chemical stability and the like, the magnetic particles are added in the preparation process of the precipitation pulp, different electromagnetic parameters are designed by adjusting the addition amount of the magnetic particles, then the magnetic precipitation pulp is mixed with the high-performance polymer fiber, and the wet papermaking process is adopted for one-step forming, so that the process is simple. The magnetic particles are added in the process of preparing the precipitation pulp, so that the magnetic particles are firmly attached, the problems of difficult dispersion and low retention rate caused by large density difference in the papermaking process are avoided, and the dispersion uniformity and the retention rate are improved. In addition, because the magnetic particles are firmly wrapped, the contact with the air can be effectively isolated, so that the oxidation and rusting of the magnetic particles are prevented, and the influence on the electromagnetic performance of the magnetic particles is avoided. The dielectric constants of the upper surface layer and the lower surface layer can be controlled by a multi-layer forming mode, so that the wave-transmitting function is achieved, the middle layer has a high dielectric constant, the wave-absorbing function is achieved, and the maximization of the electromagnetic wave absorption effect is achieved.
The material prepared by the invention can effectively solve the problem that magnetic particles are easy to fall off, has stable electromagnetic performance, high absorptivity, light weight, corrosion resistance and excellent strength, and the prepared honeycomb material has excellent performance and is an advanced magnetic material.
The invention utilizes a wet forming method to prepare a structural function integrated material integrating wave absorbing and bearing functions, relies on good wave absorbing and wave transmitting performance, excellent strength and heat resistance of raw materials, and realizes the electromagnetic parameter designability by controlling the addition amount of magnetic particles and combining the magnetic particles with a wet forming technology. The prepared magnetic material effectively solves the problems of low retention rate of magnetic particles, poor dispersibility, easy oxidation and easy shedding, has stable electromagnetic performance, and meets the development requirements of 'thin, light, wide and strong' of a new generation of wave-absorbing material.
Drawings
FIG. 1 is an SEM image of carbonyl iron particles;
FIG. 2 is an SEM image of a precipitation pulp with carbonyl iron particles;
FIG. 3 is an SEM photograph of a precipitate pulp at an intermediate layer iron carbonyl content of 50wt% in example 3, wherein A is an SEM photograph magnified 500 times; b is an SEM image magnified by 7000 times; c is SEM picture magnified 2000 times;
FIG. 4 is an SEM photograph of a precipitated pulp in example 4 with a carbonyl iron content of 400wt% in the intermediate layer.
Detailed Description
The present invention will be further described with reference to the following examples. These examples are intended to help illustrate the content of the invention and not to limit the scope of the invention.
In the following examples, the electromagnetic properties are tested according to standard SJ 20152-1995 microwave high-loss solid material complex dielectric constant and complex permeability test methods. The amounts of magnetic particles mentioned in the following examples are all percentages of magnetic particles by weight of polymer in the polymer solution.
Example 1
In the preparation process of the PBO precipitation pulp, 250wt% of carbonyl iron particles are added, wherein the carbonyl iron particles are flaky particles with the average length and width of 1 mu m and the thickness of 50nm, the SEM picture of the carbonyl iron particles is shown in figure 1, the PBO precipitation pulp containing carbonyl iron is prepared, and the SEM picture of the obtained precipitation pulp with the carbonyl iron particles is shown in figure 2.
Basis weight 150g/m according to paper design 2 Making paper, mixing 90wt% PBO precipitation pulp containing carbonyl iron particles and 10wt% PBO fiber, defibering, dewatering, forming, squeezing, and drying to constant weight to obtain the final product with quantitative of 147g/m 2 A magnetic paper base material having a thickness of 160 μm.
The retention rate of the tested paper is 98%, the 3GHz dielectric constant tested by the paper is 6.30, and the dielectric loss is between 0.10; the magnetic permeability is 1.11, and the magnetic loss is 0.50. Preparing honeycombs with 2.75mm cells by using the paper, wherein the tested dielectric constant of 3GHz is 1.42, and the dielectric loss is 0.02; the magnetic permeability is 1.03, and the magnetic loss is 0.10. The thermal dimensional shrinkage of the paper at 300 ℃ is 0.
Comparative example 1
Basis weight 150g/m according to paper design 2 Making paper with 65wt% carbonylIron particles, 25wt% of PBO precipitation pulp and 10wt% of PBO fibers, which are directly mixed and defibrated, wherein the carbonyl iron particles are sheet-shaped particles with the average length and width of 1 mu m and the thickness of 50nm, the SEM image of the carbonyl iron particles is shown in figure 1, the mixture is dewatered, formed, pressed and finally dried to constant weight, and the retention rate of the paper is 41%. A quantitative yield of 61g/m was obtained 2 A magnetic paper base material having a thickness of 132 μm.
The 3GHz dielectric constant of the paper test is 2.10, and the dielectric loss is between 0.01; the magnetic permeability is 1.00, and the magnetic loss is 0.001.
Preparing 2.75mm honeycombs from the paper, wherein the dielectric constant of the tested 3GHz is 1.5 and the dielectric loss is 0.008; magnetic permeability of 1.00 and magnetic loss of 0.001. The thermal dimensional shrinkage of the paper at 300 ℃ is 0.
Example 2
Adding 200wt% of iron-silicon-aluminum magnetic particles in the process of precipitating the aramid fiber pulp, wherein the thickness of the magnetic particles is 1 micrometer, and the length and width dimensions are 150 micrometers. Then 60wt% of aramid precipitation pulp containing iron-silicon-aluminum magnetic particles, 35wt% of aramid fiber and 5wt% of carbon fiber are mixed and defibered, and then dehydration, forming and squeezing are carried out, and finally drying is carried out to constant weight, so that the retention rate of the obtained paper is 98%. A quantitative content of 120g/m was obtained 2 A magnetic paper base material having a thickness of 80 μm.
The 3GHz dielectric constant of the paper test is 150, and the dielectric loss is 1.0; the magnetic permeability is 1.12, and the magnetic loss is 0.59. Preparing 2.75mm honeycombs from the paper, wherein the dielectric constant of the honeycomb is 7.90 and the dielectric loss of the honeycomb is 0.09 at 3 GHz; magnetic permeability of 1.05 and magnetic loss of 0.08.
Example 3
Magnetic paper-based materials are prepared using a multi-layer forming process, wherein the multiple layers consist essentially of an upper surface layer, a lower surface layer and an intermediate layer. Mixing 50wt% of PBO precipitation pulp and 50wt% of PBO fiber to prepare slurry A1; mixing 88wt% PBO magnetic precipitation pulp (magnetic particle carbonyl iron accounts for 50wt% of the polymer, SEM image of precipitation pulp containing magnetic particle carbonyl iron is shown in figure 3) with 10wt% PBO fiber and 2wt% carbon fiber to obtain slurry A2; mixing 50wt% of PBO precipitation pulp and 50wt% of PBO fiber to prepare slurry A3; dewatering A1, A2 and A3 respectively, stacking in the order of A1-A2-A3, squeezing, and drying to obtain 150g/m 2 The multilayer composite paper base material of (2).
The retention rate of the paper is 98%, the 3GHz dielectric constant 102 tested by the paper is 3GHz, and the dielectric loss is 0.9; magnetic permeability is 1.08, and magnetic loss is 0.38. The shrinkage of the paper in hot dimension at 300 ℃ is 0.
The paper is used for preparing 2.75mm honeycombs, and the tested dielectric constant of 3GHz is 5.91, and the dielectric loss is 0.67; magnetic permeability of 1.04 and magnetic loss of 0.11. The average reflectivity of the honeycomb 2-18GHz is less than-10dB, and the average reflectivity of the honeycomb 4-18GHz is less than-15 dB.
Comparative example 2
Magnetic paper-based materials are prepared using a multi-layer forming process, wherein the multiple layers consist essentially of an upper surface layer, a lower surface layer and an intermediate layer. Mixing 30wt% of PBO precipitation pulp, 50wt% of PBO fiber and 20wt% of carbon fiber to prepare slurry A1; mixing 88wt% of PBO precipitation pulp (magnetic particle carbonyl iron accounts for 50wt% of the weight of the polymer) with 10wt% of PBO fiber and 2wt% of carbon fiber to prepare slurry A2; mixing 30wt% of PBO precipitation pulp, 50wt% of PBO fiber and 20wt% of carbon fiber to prepare slurry A3; mixing A1, A2 and A3, respectively dehydrating, forming, squeezing, and drying to obtain a mixture with a quantitative rate of 150g/m 2 The paper base material of (1).
The retention rate of the paper is 98%, the 3GHz dielectric constant 132 tested by the paper is high, and the dielectric loss is 0.32; the magnetic permeability is 1.02, and the magnetic loss is 0.32.
The paper is used for preparing 2.75mm honeycombs, the 2-18GHz average reflectivity of the honeycombs is less than-5dB, and the 4-18GHz average reflectivity is less than-8 dB.
Example 4
Magnetic paper-based materials are prepared using a multi-layer forming process, wherein the multiple layers consist essentially of an upper surface layer, a lower surface layer, and an intermediate layer. Wherein the three layers all have different electromagnetic performance designs. Mixing 49wt% of aramid precipitation pulp, 50wt% of PBO fiber and 1wt% of carbon fiber to prepare slurry A1; mixing 88wt% ofAramid precipitation pulp (the weight percentage of the magnetic particle carbonyl iron accounts for 400wt% of the polymer, and the SEM image of the precipitation pulp containing the magnetic particle carbonyl iron is shown in figure 4) is mixed with 10wt% of PBO fiber and 2wt% of carbon fiber to prepare pulp A2; mixing 49.5wt% of aramid fiber precipitation, 50wt% of PBO fiber and 0.5wt% of carbon fiber to prepare slurry A3; dewatering A1, A2 and A3 on a three-layer paper machine for one time, pressing and drying to obtain the product with the basis weight of 150g/m 2 The multilayer composite paper base material of (1).
The retention rate of the paper is 98%, the 3GHz dielectric constant tested by the paper is 128, and the dielectric loss is 0.9; the magnetic permeability is 1.10, and the magnetic loss is 0.49.
Preparing 1.83mm honeycombs from the paper, wherein the tested dielectric constant of 3GHz is 6.98, and the dielectric loss is 0.78; magnetic permeability of 1.06 and magnetic loss of 0.12. The average reflectivity of the honeycomb at 0.3-1GHz is less than-6 dB, the average reflectivity of the honeycomb at 1-2GHz is less than-8 dB, the average reflectivity of the honeycomb at 2-18GHz is less than-10 dB, and the average reflectivity of the honeycomb at 4-18GHz is less than-18 dB.
Comparative example 3
Mixing 49wt% of aramid fiber magnetic precipitation pulp (the weight percentage of magnetic particle carbonyl iron is 400wt% of the polymer, and the SEM image of the precipitation pulp containing the magnetic particle carbonyl iron is shown in figure 4) with 50wt% of PBO fiber and 1wt% of carbon fiber to prepare pulp A1; mixing 88wt% of aramid fiber precipitation pulp (magnetic particle carbonyl iron accounts for 400wt% of the polymer), 10wt% of PBO fiber and 2wt% of carbon fiber to prepare pulp A2; mixing 49.5wt% of aramid precipitation pulp, 50wt% of PBO fiber and 0.5wt% of carbon fiber to prepare slurry A3; uniformly mixing A1, A2 and A3, dehydrating, forming, squeezing and drying to obtain the product with the quantitative of 150g/m 2 A paper based material.
The retention rate of the paper is 98%, the 3GHz dielectric constant 140 tested by the paper is 140, and the dielectric loss is 0.68; the magnetic permeability is 1.11, and the magnetic loss is 0.60.
When the paper is used for preparing a honeycomb with the thickness of 1.83mm, the average reflectivity of 0.3-1GHz is less than-2dB, the average reflectivity of 1-2GHz is less than-3dB, the average reflectivity of 2-18GHz is less than-8dB, and the average reflectivity of 4-18GHz is less than-10 dB.
Example 5
Adding 500wt% carbonyl iron particles in the preparation process of PBO precipitation pulp, then defibering, dehydrating, forming, squeezing 100wt% PBO precipitation pulp, and finally drying to constant weight to obtain the product with the quantitative of 60g/m 2 A magnetic paper base material having a thickness of 80 μm. The retention of the magnetic particles is tested to be 97%, and the dielectric constant of the material is tested to be: 12.30, dielectric loss: 0.25; magnetic permeability: 1.21, magnetic loss: 0.26.

Claims (10)

1. a magnetic paper base material is composed of magnetic precipitation pulp, high-performance polymer fibers and conductive fibers, wherein the material is composed of an upper layer, a middle layer and a lower layer, the magnetic precipitation pulp accounts for 0-10wt% of the magnetic paper base material in the upper surface layer and the lower surface layer, the conductive fibers account for less than 3wt% of the magnetic paper base material, and the balance of the high-performance polymer fibers; in the middle layer, the weight percentage of the magnetic precipitation pulp accounts for 10-100wt% of the magnetic paper base material, the weight percentage of the conductive fiber accounts for 0-25wt% of the magnetic paper base material, and the balance is high-performance polymer fiber;
the magnetic precipitation pulp is prepared by mixing magnetic particles and polymer solution through a precipitation process; the addition amount of the magnetic particles is 100-400wt% of the weight of the polymer in the polymer solution;
the magnetic particles are in the shape of platelets, wherein the size ranges are: the thickness is less than 20 μm, and the length and width are 20-300 μm; or fibrous, wherein the diameter ranges are: 10nm-150 μm, length 150 μm-6mm;
the magnetic particles are selected from one or more of carbonyl iron, iron-silicon-aluminum, iron, cobalt and nickel.
2. The magnetic paper-based material according to claim 1, wherein in the upper and lower surface layers, the magnetic precipitation pulp accounts for 0-3wt% of the magnetic paper-based material, the conductive fiber accounts for less than 3wt% of the magnetic paper-based material, and the balance is high-performance polymer fiber; in the intermediate layer, the weight percentage of the magnetic precipitation pulp accounts for 10-100wt% of the magnetic paper base material, the weight percentage of the conductive fiber accounts for 0-25wt% of the magnetic paper base material, and the balance is high-performance polymer fiber.
3. A magnetic paper-based material according to claim 1 or 2, wherein the polymer in the polymer solution is a low dielectric loss polymer selected from one or more of high performance polymers such as poly-p-Phenylene Benzobisoxazole (PBO), aramid and polyimide.
4. The magnetic paper based material according to claim 3, wherein the polymer in the polymer solution is poly-p-Phenylene Benzobisoxazole (PBO).
5. The magnetic paper-based material according to claim 1 or 2, characterized in that the magnetic precipitation pulp has a freeness of 32-80 ° SR.
6. The magnetic paper based material according to claim 5, characterized in that the magnetic precipitation pulp has a freeness of 40 ° -80 ° SR.
7. The magnetic paper based material according to claim 1 or 2, characterized in that the magnetic particles are sheet-like in shape with a size range of: the thickness is less than 1 μm, and the length and width are 150-200 μm; or fibrous, wherein the diameter ranges are: 10nm-30 mu m, and the length is 150 mu m-3mm.
8. A magnetic paper based material according to claim 1 or 2, wherein the high performance polymer fibres are selected from one or more of PBO fibres, aramid fibres and polyimide fibres.
9. The magnetic paper based material according to claim 1 or 2, wherein the electrically conductive fibers are selected from one or more of carbon fibers and nickel-plated carbon fibers; the length of the conductive fiber is 0.5mm-15mm.
10. A magnetic paper-based material according to claim 9, wherein the length of the electrically conductive fibres is 3-9 mm.
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