CN110278702B - High-stretch high-elasticity electromagnetic shielding composite material and preparation method thereof - Google Patents
High-stretch high-elasticity electromagnetic shielding composite material and preparation method thereof Download PDFInfo
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Abstract
The invention provides a high-tensile high-elasticity electromagnetic shielding composite material, which is a structural material formed by repeatedly overlapping a plurality of composite layers on an elastic substrate, wherein the composite layers sequentially comprise a shielding layer, a conducting layer and a dielectric layer from bottom to top, and a layer of bottom rubber is detachably arranged at the bottom of the elastic substrate; and the shielding layer and the conductive layer are soaked by ethanol after being sprayed. Meanwhile, the multilayer high-tensile electromagnetic shielding composite material obtained by the preparation method of the material can keep stable mechanical properties and shielding properties, and still keeps the stability of electrical properties and shielding properties in the processes of stretching, twisting and bending. The strain range of the conventional stretchable electromagnetic shielding material is only about 50%, the strain range of the multilayer high-stretching electromagnetic shielding composite material provided by the invention can reach 600-650%, and the ultrahigh-deformation electromagnetic shielding composite material is really realized.
Description
Technical Field
The invention belongs to the field of electromagnetic shielding materials, and particularly relates to a high-tensile high-elasticity electromagnetic shielding composite material and a preparation method thereof.
Background
The rapid development of electronic and electrical equipment in the information era brings convenience to people, and simultaneously generates a large number of negative effects, such as electromagnetic information leakage, electromagnetic environmental pollution, electromagnetic interference and other new environmental pollution problems. High-performance electromagnetic wave shielding materials have become a key technology for solving the problem of electromagnetic wave pollution. With the advent of the high-frequency and high-speed 5G era and the development of wearable equipment, higher requirements are put on electromagnetic shielding materials. Common electromagnetic shielding materials comprise metal materials, magnetic materials, conductive polymers, carbon-based conductive composite materials and the like, and the excellent electromagnetic shielding performance is endowed by good electric loss and magnetic loss. The traditional metal material and magnetic material have high density, and along with the development of electronic equipment towards portability, the electromagnetic shielding material is required to have the characteristics of high shielding performance, light weight and the like. Therefore, it is a great challenge to develop an electromagnetic wave shielding material that is efficient, lightweight, flexible, stretchable, and highly elastic.
The graphene has the characteristics of high aspect ratio, high electric conductivity and thermal conductivity, large specific surface area, low density and the like, the intrinsic strength of the graphene is up to 130 GPa, and the electron mobility at normal temperature can reach 15000 cm2／(VS), is currently the least resistive material. And the graphene has a room-temperature quantum Hall effect and good ferromagnetism, and compared with materials such as graphite, carbon fiber and carbon nanotube, the graphene with unique performance can break through the original limitation of carbon materials, and becomes a novel effective electromagnetic shielding and microwave absorbing material.
In the prior art, most electromagnetic shielding materials are made of hard materials, although the electromagnetic shielding materials can be stretched and play a certain electromagnetic shielding role, the structure of the conductive materials is obviously changed in the stretching process, so that the electrical performance is reduced, the electromagnetic shielding performance is reduced, and the electromagnetic shielding materials are heavier and have a small stretching strain range. Therefore, how to develop a high elastic shielding material with high tensile strain and high electrical stability is an urgent need in the field of stretchable devices.
Disclosure of Invention
Aiming at the defects, the invention provides a high-stretch high-elasticity electromagnetic shielding composite material, which has the specific scheme that: the composite material is a structural material formed by repeatedly overlapping a plurality of composite layers on an elastic substrate, the composite layers sequentially comprise a shielding layer, a conductive layer and a dielectric layer from bottom to top, and a layer of bottom rubber is detachably arranged at the bottom of the elastic substrate; and the shielding layer and the conductive layer are soaked by ethanol after being sprayed.
As an improvement, the elastic substrate is a hard rubber layer with the hardness of 50-70 HA; the bottom rubber is arranged into a soft rubber layer at the bottom of the elastic base by adopting a spraying method, and the hard rubber layer is arranged into a length of 90-100mm and a width of 65-85 mm.
As an improvement, the soft rubber layer is obtained by dissolving a rubber solution in any one of cyclohexane, tetrahydrofuran, petroleum ether, hexane, pentane and isooctane solvent; the rubber solution is prepared by mixing and hot melting white oil and SEBS according to the mass ratio of (5-7) to 1, wherein the dissolving mass volume ratio of the rubber solution to cyclohexane is 1 (10-40).
As an improvement, the spraying thickness is set to be (0.5-1 μm) when the soft rubber layer is prepared, and the spraying time is set to be (1-5 s).
As an improvement, the composite material comprises 50-10 composite layers, wherein the thickness ratio of the shielding layer to the conducting layer to the dielectric layer in the single-layer composite layer is 1:1 (5-10), and the thickness ratios of the shielding layer to the conducting layer to the dielectric layer in the multi-layer composite layer are set to be the same or different.
As an improvement, the shielding layer is prepared by wrapping a nano ferromagnetic material with graphene by adopting a coprecipitation method, and the nano ferromagnetic material is selected from any one or more than two of Fe, Co, Ni and an alloy or an oxide thereof.
As an improvement, the conducting layer is formed by compounding graphene and nano silver particles, and a magnetron sputtering method is adopted during compounding; the graphene comprises graphene fibers and graphene sheets, and the graphene sheets are selected from 1-5 layers.
Meanwhile, the preparation method of the high-stretch high-elasticity electromagnetic shielding composite material comprises the following specific steps:
(1) selection of the elastic substrate: selecting a hard rubber layer with the hardness of 50-70 HA, the length of 90-100mm and the width of 65-85mm as an elastic substrate;
(2) preparation of a bottom rubber layer: spraying a soft rubber layer on the elastic substrate in the step (1) as a bottom layer, wherein the bottom layer is detachably arranged; the soft rubber layer is obtained by dissolving a rubber solution in any one of solvents of cyclohexane, tetrahydrofuran, petroleum ether, hexane, pentane and isooctane; the rubber solution is prepared by mixing and hot melting white oil and SEBS according to the mass ratio of (5-7) to 1, wherein the dissolving mass-volume ratio of the rubber solution to cyclohexane is 1 (10-40);
(3) and (3) tensile deformation treatment: axially stretching the elastic substrate sprayed with the bottom rubber layer in the step (2) to 5-10 times of the original length and transversely stretching to 1-5 times of the original length according to the requirement;
(4) preparing a shielding layer: preparation of graphene coated nano Fe by coprecipitation method3O4The solution is used as a shielding layer, the shielding layer is sprayed on the surface of the composite substrate obtained in the step (3) by a spraying pump, and 1-5ml of ethanol is dripped on the surface of the shielding layer to completely soak the shielding layer;
(5) preparing a conductive layer: after the ethanol solvent in the step (4) is volatilized, spraying the graphene solution on the surface by using a spraying pump to form a graphene film, sputtering a layer of Ag nano particles on the graphene by using a magnetron sputtering method, and dripping 2-3ml of ethanol on the surface of the conducting layer to completely soak the conducting layer; after the ethanol solvent is volatilized, spraying a layer of soft rubber layer in the step (2) on the surface, and reducing the whole structure to the original size before the stretching after a period of time;
(6) preparing a dielectric layer: spraying a rubber solution on the surface of the structure obtained in the step (5) by using a spraying pump as a dielectric layer, wherein the rubber solution is the same as that in the step (2); wherein the pressure of the spray pump is 25-35psi, the spray pen is vertical to the surface to be sprayed, the distance between the spray pen and the surface to be sprayed is 9-20cm, the spray pen is moved left and right to spray uniformly;
(7) preparing a multilayer composite layer: repeating the steps (4) to (6) according to the requirement, and setting the number of the composite layers to be 50-100;
(8) and (5) after the step (7) is finished, removing the composite layer from the soft rubber layer of the elastic substrate to obtain the stable high-tensile high-elasticity electromagnetic shielding composite material.
As an improvement, in the step (4), nano Fe is coated by graphene3O4The solution is 100-210ml, the pressure of a spraying pump is 30-40psi, and a spray pen is vertical to the direction of the surface to be sprayed, wherein the distance between the spray pen and the surface to be sprayed is 5-20 cm; in the step (5), the graphene solution is obtained by firstly performing ultrasonic dispersion on graphene by using ethanol, and 50-210ml is adopted, wherein the volume mass-volume ratio of the ethanol to the graphene is (350-420) ml: 1g, and the ultrasonic time is 12-19 min; the graphene solution spraying method is the same as the spraying method of the dielectric layer in the step (6).
As a modification, 200ml of 100-200 rubber solution is adopted in the step (6), and the thickness of the dielectric layer after spraying is set to be any one of 3.5-6.5 microns, 8-12 microns, 13-16.5 microns and 18-22 microns.
Has the advantages that: compared with the prior art, the high-tensile high-electromagnetic-shielding composite material provided by the invention has the following effects: (1) the shielding layer is made of graphene coated metal ferromagnetic materials, the conducting layer is made of graphene-nano silver composite materials, and graphene has excellent electrical property and mechanical property, so that the shielding property is prevented from being influenced due to reduction of the electrical property caused by separation of graphene sheets in the stretching process; (2) the dielectric layer prepared by the method is used as an elastic layer, has ultrahigh tensile property, can be stretched by more than 10 times at most, is one of materials with the largest stretching times in the prior elastomers, and lays a foundation for realizing the ultrahigh-stretching electromagnetic shielding composite material.
The foregoing description is only an overview of the technical solutions of the present invention, and in order to make the technical solutions of the present invention more clearly understood and to implement them in accordance with the contents of the description, the following detailed description is given with reference to the preferred embodiments of the present invention and the accompanying drawings.
Drawings
Fig. 1 is a schematic structural view of a multilayer high-tensile electromagnetic shielding composite material of the present invention in a stretched state.
Fig. 2 is a schematic structural view of the multilayer high-tensile electromagnetic shielding composite material in a contracted state.
Detailed Description
The following detailed description of embodiments of the present invention is provided in connection with the accompanying drawings and examples. The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.
The multilayer high-tensile electromagnetic shielding composite material is prepared by alternately superposing a shielding layer, a conducting layer and a dielectric layer on a substrate structure layer by layer. The detailed steps are as follows:
(1) selection of the elastic substrate: when preparing the multilayer high-tension electromagnetic shielding composite material, in order to ensure that the stretching multiple of the prepared composite material is not reduced due to the increase of the thickness, the selected base material cannot be too soft, and the too soft material cannot be bound back to the initial length due to the increase of the thickness of the composite material. Here we select a hard rubber with high resilience as the elastic base, the elastic base size: 90-100mm and 65-85mm in width.
(2) Preparation of a bottom rubber layer: and (2) spraying a rubber layer on the elastic substrate in the step (1) by using a rubber solution as a bottom layer. The rubber solution is prepared by dissolving super-soft rubber prepared by mixing and hot melting white oil and SEBS according to the mass ratio of (5-7): 1 in an organic solvent. The preferred solvent is cyclohexane, the dissolving mass-to-volume ratio generally being 1 (10-40), preferably 1: 23, which primarily serves to facilitate later removal of the sample from the substrate.
(3) And (3) tensile deformation treatment: and (3) axially stretching the substrate sprayed with the bottom rubber in the step (2) to 5-10 times, preferably 5 times, of the original length and transversely stretching to 1-5 times, preferably 2 times, of the original length according to needs.
(4) Preparing a shielding layer: preparation of graphene coated nano Fe by coprecipitation method3O4Coating graphene with Fe3O4The solution is sprayed on the surface of a substrate to be used as a shielding layer, and 1-5ml of ethanol is dripped to completely soak the shielding layer, so that the close fit with the substrate is enhanced.
(5) Preparing a conductive layer: and (3) spraying 50-210ml of graphene solution on the surface of the shielding layer to serve as a conductive layer, dripping 2-3ml of ethanol to completely soak the shielding layer after the completion of paving, and spraying a thin layer of rubber solution on the shielding layer after the ethanol is volatilized, wherein the rubber solution is the same as that used in the step (2), and has the function of preventing the conductive layer from being adhered together after retraction. The entire structure is then retracted to its original state.
(6) Preparing a dielectric layer: and (5) spraying a rubber solution on the surface of the structure as a dielectric layer, wherein the rubber solution is mainly used for isolating adjacent conductive layers to prepare the composite material with the required number of layers. The spraying thickness of the rubber solution can be controlled manually, and the composite material with the required thickness can be prepared by controlling the spraying time under the same layer number. The number of the dielectric layers after spraying is 50-100, and the thickness is set to be any one of 3.5-6.5 microns, 8-12 microns, 13-16.5 microns and 18-22 microns, preferably four different inner layer thicknesses of 50 layers, 5 microns, 10 microns, 15 microns and 20 microns. The spraying thickness is not suitable to be too thin, and the sample is too thin and is not easy to be torn off from the substrate; when the spraying is too thick, large wrinkles are formed, and the conductive layer is easy to break in the stretching process, so that the shielding performance is affected. The spraying process can be manually operated or mechanically sprayed.
(7) And (5) repeating the steps (4), (5) and (6) according to the required number of layers.
(8) And (5) after the step (7) is finished, removing the composite layer from the soft rubber layer of the elastic substrate to obtain the stable high-tensile high-elasticity electromagnetic shielding composite material.
The present invention is explained for the above implementation steps as follows:
the graphene-based high-stretch and high-elasticity electromagnetic shielding composite material is composed of a graphene composite material and rubber, wherein the graphene with fewer layers is selected, and the larger the number of the conductive layers is, the better the conductivity is.
The prepared electromagnetic shielding composite material releases the pre-strain, when the composite material returns to the initial state from stretching, the conducting layer generates a periodic fold structure under the extrusion action of rubber, and the fold structure ensures that the composite material keeps stable resistance in a large stretching and shrinking process, so that the stability of the shielding performance is ensured.
The preparation method of the shielding layer in the step (4) comprises the following steps: the shielding layer is obtained by spraying graphene solution through a spraying pump. 100-210ml of mixed solution is placed in a spray gun, and 200ml of graphene coated Fe is preferably selected3O4The content was 0.5 g. Adjusting the air pressure of a spray pump to a fixed value, preferably 30-40psi, further preferably 40psi, keeping the spray pen perpendicular to the substrate and at a certain distance from the substrate, setting the distance between the spray pen and the substrate to be approximately 5-20cm, preferably 10cm, and moving the spray pen at a constant speed from left to right to make the shielding agent uniformly fall on the substrate.
In the step (5), the graphene solution is obtained by firstly performing ultrasonic dispersion on graphene by using ethanol, and 50-210ml is adopted, wherein the volume mass-volume ratio of the ethanol to the graphene is (350-420) ml: 1g, and the ultrasonic time is 12-19 min; the graphene solution spraying method is the same as the spraying method of the dielectric layer in the step (6).
The preparation method of the conducting layer in the step (5) is as follows: preferably, 50-210ml of solution is selected and placed in a spray gun, the air pressure of a spraying pump is adjusted to 30-40psi, the spray pen is kept vertical to the direction of the substrate and kept 5-20cm away from the substrate, and the spray pen is moved at a constant speed from side to side, so that the conductive agent is uniformly dropped on the substrate.
The preparation method of the dielectric layers with different thicknesses in the step (5) comprises the following steps: the dielectric layer is obtained by spraying a rubber solution through a spraying pump, the spraying method is the same as the method for preparing the conductive layer, and the dielectric layer with the required thickness is obtained by controlling the spraying time.
The method for removing the composite layer from the soft rubber layer of the elastic substrate in the step (8) is as follows: one end of the composite layer is first torn off a short distance and then pulled slightly upwards along the part to make the sample slowly separated from the substrate. The speed in the drawing process is not suitable to be too fast, so that the sample fracture caused by too fast drawing speed is prevented. The process can be operated mechanically or manually.
Example 1
(1) Selection of the elastic substrate: when preparing the multilayer high-tension electromagnetic shielding composite material, in order to ensure that the stretching multiple of the prepared composite material is not reduced due to the increase of the thickness, the selected base material cannot be too soft, and the too soft material cannot be bound back to the initial length due to the increase of the thickness of the composite material. Here we select a hard rubber with high resilience as the elastic base, the elastic base size: 90mm and 85mm in width.
(2) Preparation of a bottom rubber layer: and (2) spraying a rubber layer on the elastic substrate in the step (1) by using a rubber solution as a bottom layer. The rubber solution is prepared by dissolving super-soft rubber prepared by mixing and hot melting white oil and SEBS according to the mass ratio of 7:1 in an organic solvent. The solvent is preferably cyclohexane, and may be any of tetrahydrofuran, petroleum ether, hexane, pentane, and isooctane. The mass to volume ratio of dissolution is typically 1:40, and its main function is to facilitate later removal of the sample from the substrate.
(3) And (3) tensile deformation treatment: and (3) axially stretching the substrate sprayed with the bottom layer rubber in the step (2) to 5 times of the original length and transversely stretching to 1 time of the original length according to the requirement.
(4) Preparing a shielding layer: preparation of graphene coated nano Fe by coprecipitation method3O4Coating graphene with Fe3O4The solution is sprayed on the surface of a substrate to be used as a shielding layer, and 1ml of ethanol is dripped to completely soak the shielding layer, so that the close fit with the substrate is enhanced.
(5) Preparing a conductive layer: and (3) spraying 50ml of graphene solution on the surface of the shielding layer to serve as a conductive layer, dripping 2ml of ethanol into the shielding layer after the shielding layer is paved to completely soak the shielding layer, spraying a thin layer of rubber solution on the shielding layer after the ethanol is volatilized, wherein the rubber solution is the same as that used in the step (2), and has the function of preventing the conductive layer from being adhered together after retraction. The entire structure is then retracted to its original state.
(6) Preparing a dielectric layer: and (5) spraying a rubber solution on the surface of the structure as a dielectric layer, wherein the rubber solution is mainly used for isolating adjacent conductive layers to prepare the composite material with the required number of layers. The spraying thickness of the rubber solution can be controlled manually, and the composite material with the required thickness can be prepared by controlling the spraying time under the same layer number. The number of dielectric layers after spraying is 50, and the thickness is set to be any one of 3.5 micrometers, 8 micrometers, 13 micrometers and 18 micrometers. The spraying thickness is not suitable to be too thin, and the sample is too thin and is not easy to be torn off from the substrate; when the spraying is too thick, large wrinkles are formed, and the conductive layer is easy to break in the stretching process, so that the shielding performance is affected. The spraying process can be manually operated or mechanically sprayed.
(7) And (5) repeating the steps (4), (5) and (6) according to the required number of layers.
(8) And (5) after the step (7) is finished, removing the composite layer from the soft rubber layer of the elastic substrate to obtain the stable high-tensile high-electromagnetic-shielding composite material.
The preparation method of the shielding layer in the step (4) comprises the following steps: the shielding layer is obtained by spraying graphene solution through a spraying pump. Placing 100ml of mixed solution in a spray gun, and selecting 100ml of graphene coated Fe3O4The content was 0.25 g. Adjusting the pressure of the spray pump to a fixed value, preferably 30psi, maintaining the spray pen perpendicular to the substrate and at a distance from the substrate, and positioning the spray pen and the substrateThe distance is about 5cm, preferably 10cm, and the spray pen is moved at a constant speed from left to right to make the shielding agent uniformly fall on the substrate. The preparation method of the conducting layer in the step (5) is as follows: preferably, 210ml of solution is selected and placed in a spray gun, the air pressure of a spray pump is adjusted to 30psi, the spray pen is kept perpendicular to the substrate and kept 15cm away from the substrate, and the spray pen is moved at a constant speed from side to side, so that the conductive agent uniformly falls on the substrate.
In the step (5), the graphene is obtained by performing ultrasonic dispersion on ethanol, 50ml is adopted, and the volume-to-volume ratio of the ethanol to the graphene is 420 ml: 1g, and the ultrasonic time is 19 min; the graphene solution spraying method is the same as the spraying method of the electrolyte layer in the step (6).
The preparation method of the conducting layer in the step (5) is as follows: preferably, 50ml of solution is selected and placed in a spray gun, the air pressure of a spray pump is adjusted to 30psi, the spray pen is kept vertical to the substrate and kept 5cm away from the substrate, and the spray pen is moved at a constant speed from side to side, so that the conductive agent is uniformly dropped on the substrate.
The preparation method of the dielectric layers with different thicknesses in the step (5) comprises the following steps: the dielectric layer is obtained by spraying rubber solution through a spraying pump, the spraying method is the same as the method for preparing the conductive layer, and the dielectric layer with the required thickness is obtained by controlling the spraying time.
After the elastic substrate and the bottom rubber layer are torn off, the obtained composite material comprises 50 composite layers, wherein the thickness ratio of the shielding layer, the conducting layer and the dielectric layer in the single-layer composite layer is 1:1: 5, and the thickness ratios of the shielding layer, the conducting layer and the dielectric layer in the multi-layer composite layer are set to be the same or different.
The obtained multilayer high-tensile electromagnetic shielding composite material can keep stable mechanical property and shielding property, and still keep stable electrical property and shielding property in the processes of stretching, twisting and bending. The strain range of the conventional stretchable electromagnetic shielding material is only about 50%, and the strain range of the multilayer high-stretching electromagnetic shielding composite material provided by the invention can reach 610%. The electromagnetic shielding composite material with ultra-large deformation is really realized.
Example 2
(1) Selection of the elastic substrate: when preparing the multilayer high-tension electromagnetic shielding composite material, in order to ensure that the stretching multiple of the prepared composite material is not reduced due to the increase of the thickness, the selected base material cannot be too soft, and the too soft material cannot be bound back to the initial length due to the increase of the thickness of the composite material. Here we select a hard rubber with high resilience as the elastic base, the elastic base size: 100mm and 65mm in width.
(2) Preparation of a bottom rubber layer: and (2) spraying a rubber layer on the elastic substrate in the step (1) by using a rubber solution as a bottom layer. The rubber solution is prepared by dissolving super-soft rubber prepared by mixing and hot melting white oil and SEBS according to the mass ratio of 5:1 in an organic solvent. The preferred solvent is cyclohexane, typically in a mass to volume ratio of 1: 10, which has the main effect of facilitating later removal of the sample from the substrate.
(3) And (3) tensile deformation treatment: and (3) axially stretching the substrate sprayed with the bottom layer rubber in the step (2) to 10 times of the original length and transversely stretching to 5 times of the original length according to the requirement.
(4) Preparing a shielding layer: preparation of graphene coated nano Fe by coprecipitation method3O4Coating graphene with Fe3O4The solution is sprayed on the surface of a substrate to be used as a shielding layer, and 1ml of ethanol is dripped to completely soak the shielding layer, so that the close fit with the substrate is enhanced.
(5) Preparing a conductive layer: and (3) spraying 210ml of graphene solution on the surface of the shielding layer to serve as a conducting layer, dripping 3ml of ethanol to completely soak the shielding layer after the completion of paving, spraying a thin layer of rubber solution on the shielding layer after the ethanol is volatilized, wherein the rubber solution is the same as that used in the step (2), and has the function of preventing the conducting layer from being adhered together after retraction. The entire structure is then retracted to its original state.
(6) Preparing a dielectric layer: and (5) spraying a rubber solution on the surface of the structure as a dielectric layer, wherein the rubber solution is mainly used for isolating adjacent conductive layers to prepare the composite material with the required number of layers. The spraying thickness of the rubber solution can be controlled manually, and the composite material with the required thickness can be prepared by controlling the spraying time under the same layer number. The number of the dielectric layers after spraying is 100, and the thickness is set to be any one inner layer thickness of 6.5 microns, 12 microns, 16.5 microns and 22 microns. The spraying thickness is not suitable to be too thin, and the sample is too thin and is not easy to be torn off from the substrate; when the spraying is too thick, large wrinkles are formed, and the conductive layer is easy to break in the stretching process, so that the shielding performance is affected. The spraying process can be manually operated or mechanically sprayed.
(7) And (5) repeating the steps (4), (5) and (6) according to the required number of layers.
(8) And (5) after the step (7) is finished, removing the composite layer from the soft rubber layer of the elastic substrate to obtain the stable high-tensile high-electromagnetic-shielding composite material.
The preparation method of the shielding layer in the step (4) comprises the following steps: the shielding layer is obtained by spraying graphene solution through a spraying pump. Placing 210ml of mixed solution in a spray gun, and selecting 210ml of graphene coated Fe3O4The content was 0.65 g. Adjusting the air pressure of a spray pump to a fixed value, preferably 40psi, keeping the spray pen perpendicular to the substrate and at a certain distance from the substrate, setting the distance between the spray pen and the substrate to be about 20cm, preferably 10cm, and moving the spray pen at a constant speed from left to right to make the shielding agent uniformly fall on the substrate.
In the step (5), the graphene is obtained by performing ultrasonic dispersion on the graphene by using 210ml of ethanol, wherein the volume-to-volume ratio of the ethanol to the graphene is 350 ml: 1g, and the ultrasonic time is 12 min; the graphene solution spraying method is the same as the spraying method of the electrolyte layer in the step (6).
The preparation method of the conducting layer in the step (5) is as follows: preferably, 210ml of solution is selected and placed in a spray gun, the air pressure of a spray pump is adjusted to 40psi, the spray pen is kept perpendicular to the substrate and 20cm away from the substrate, and the spray pen is moved at a constant speed from side to side, so that the conductive agent uniformly falls on the substrate.
The preparation method of the dielectric layers with different thicknesses in the step (5) comprises the following steps: the dielectric layer is obtained by spraying rubber solution through a spraying pump, the spraying method is the same as the method for preparing the conductive layer, and the dielectric layer with the required thickness is obtained by controlling the spraying time.
After the elastic substrate and the bottom rubber layer are torn off, the obtained composite material comprises 100 composite layers, wherein the thickness ratio of the shielding layer, the conducting layer and the dielectric layer in the single-layer composite layer is 1:1: 10, and the thickness ratios of the shielding layer, the conducting layer and the dielectric layer in the multi-layer composite layer are set to be the same or different.
The obtained multilayer high-tensile electromagnetic shielding composite material can keep stable mechanical property and shielding property, and still keep stable electrical property and shielding property in the processes of stretching, twisting and bending. The strain range of the conventional stretchable electromagnetic shielding material is only about 50%, and the strain range of the multilayer high-stretching electromagnetic shielding composite material provided by the invention can reach 615%. The electromagnetic shielding composite material with ultra-large deformation is really realized.
Example 3
(1) Selection of the elastic substrate: when preparing the multilayer high-tension electromagnetic shielding composite material, in order to ensure that the stretching multiple of the prepared composite material is not reduced due to the increase of the thickness, the selected base material cannot be too soft, and the too soft material cannot be bound back to the initial length due to the increase of the thickness of the composite material. Here we select a hard rubber with high resilience as the elastic base, the elastic base size: 95mm and 75mm in width.
(2) Preparation of a bottom rubber layer: and (2) spraying a rubber layer on the elastic substrate in the step (1) by using a rubber solution as a bottom layer. The rubber solution is prepared by dissolving super-soft rubber prepared by mixing and hot melting white oil and SEBS according to the mass ratio of 6:1 in an organic solvent. The preferred solvent is cyclohexane, typically in a mass to volume ratio of 1: 23, which serves primarily to facilitate later removal of the sample from the substrate.
(3) And (3) tensile deformation treatment: and (3) axially stretching the substrate sprayed with the bottom layer rubber in the step (2) to 5 times of the original length and transversely stretching to 2 times of the original length according to the requirement.
(4) Preparing a shielding layer: preparation of graphene coated nano Fe by coprecipitation method3O4Coating graphene with Fe3O4The solution is sprayed on the surface of a substrate to be used as a shielding layer, and 1.5ml of ethanol is dripped to completely soak the shielding layer, so that the close fit with the substrate is enhanced.
(5) Preparing a conductive layer: and (3) spraying 175ml of graphene solution on the surface of the shielding layer to serve as a conducting layer, dripping 2.5ml of ethanol to completely soak the shielding layer after the laying is finished, and spraying a thin layer of rubber solution on the shielding layer after the ethanol is volatilized, wherein the rubber solution is the same as that used in the step (2), and has the function of preventing the conducting layer after retraction from being adhered together. The entire structure is then retracted to its original state.
(6) Preparing a dielectric layer: and (5) spraying a rubber solution on the surface of the structure as a dielectric layer, wherein the rubber solution is mainly used for isolating adjacent conductive layers to prepare the composite material with the required number of layers. The spraying thickness of the rubber solution can be controlled manually, and the composite material with the required thickness can be prepared by controlling the spraying time under the same layer number. The number of the dielectric layers after spraying is 50, and the thickness is set to be any one of four different inner layer thicknesses of 5 micrometers, 10 micrometers, 15 micrometers and 20 micrometers. The spraying thickness is not suitable to be too thin, and the sample is too thin and is not easy to be torn off from the substrate; when the spraying is too thick, large wrinkles are formed, and the conductive layer is easy to break in the stretching process, so that the shielding performance is affected. The spraying process can be manually operated or mechanically sprayed.
(7) And (5) repeating the steps (4), (5) and (6) according to the required number of layers.
(8) And (5) after the step (7) is finished, removing the composite layer from the soft rubber layer of the elastic substrate to obtain the stable high-tensile high-electromagnetic-shielding composite material.
The preparation method of the shielding layer in the step (4) comprises the following steps: the shielding layer is obtained by spraying graphene solution through a spraying pump. Putting 200ml of mixed solution into a spray gun, and selecting 200ml of graphene coated Fe3O4The content was 0.5 g. Adjusting the air pressure of a spray pump to a fixed value, preferably 40psi, keeping the spray pen perpendicular to the substrate and at a certain distance from the substrate, setting the distance between the spray pen and the substrate to be about 10cm, and moving the spray pen at a constant speed from left to right to make the shielding agent uniformly fall on the substrate.
And (5) carrying out ultrasonic dispersion on the graphene by using ethanol to obtain 165ml, wherein the volume-to-volume ratio of the ethanol to the graphene is 385 ml: 1g, and the ultrasonic time is 15.5 min; the graphene solution spraying method is the same as the spraying method of the electrolyte layer in the step (6).
The preparation method of the conducting layer in the step (5) is as follows: preferably, 176ml of solution is selected and placed in a spray gun, the air pressure of a spray pump is adjusted to 35psi, the spray pen is kept perpendicular to the substrate and kept 12cm away from the substrate, and the spray pen is moved at a constant speed from side to side, so that the conductive agent is uniformly dropped on the substrate.
The preparation method of the dielectric layers with different thicknesses in the step (5) comprises the following steps: the dielectric layer is obtained by spraying rubber solution through a spraying pump, the spraying method is the same as the method for preparing the conductive layer, and the dielectric layer with the required thickness is obtained by controlling the spraying time.
After the elastic substrate and the bottom rubber layer are torn off, the obtained composite material comprises 75 composite layers, wherein the thickness ratio of the shielding layer, the conducting layer and the dielectric layer in the single-layer composite layer is 1:1:8, and the thickness ratios of the shielding layer, the conducting layer and the dielectric layer in the multi-layer composite layer are set to be the same or different.
The obtained multilayer high-tensile electromagnetic shielding composite material can keep stable mechanical property and shielding property, and still keep stable electrical property and shielding property in the processes of stretching, twisting and bending. The strain range of the conventional stretchable electromagnetic shielding material is only about 50%, and the strain range of the multilayer high-stretching electromagnetic shielding composite material provided by the invention can reach 620%. The electromagnetic shielding composite material with ultra-large deformation is really realized.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (4)
1. The high-tensile high-elasticity electromagnetic shielding composite material is characterized in that the composite material is a structural material formed by repeatedly overlapping a plurality of composite layers on an elastic substrate, the composite layers sequentially comprise a shielding layer, a conducting layer and a dielectric layer from bottom to top, and a layer of bottom rubber is detachably arranged at the bottom of the elastic substrate; soaking the shielding layer and the conductive layer with ethanol after spraying; the shielding layer is prepared by coating a nano ferromagnetic material with graphene by adopting a coprecipitation method, wherein the nano ferromagnetic material is selected from any one or more than two of Fe, Co, Ni and alloy or oxide thereof; the conducting layer is formed by compounding graphene and nano silver particles, and a magnetron sputtering method is adopted during compounding; the graphene comprises graphene fibers and graphene sheets, and the graphene sheets are selected from 1-5 layers;
the composite material comprises 50-100 composite layers, wherein the thickness ratio of a shielding layer to a conducting layer to a dielectric layer in a single-layer composite layer is 1:1 (5-10), and the thickness ratios of the shielding layer to the conducting layer to the dielectric layer in a multi-layer composite layer are set to be the same or different;
the elastic substrate is a hard rubber layer with the hardness of 50-70 HA; the bottom rubber is arranged into a soft rubber layer at the bottom of the elastic substrate by adopting a spraying method;
the soft rubber layer is obtained by dissolving a rubber solution in any one of solvents of cyclohexane, tetrahydrofuran, petroleum ether, hexane, pentane and isooctane; the rubber solution is prepared by mixing and hot melting white oil and SEBS according to the mass ratio of (5-7) to 1, wherein the dissolving mass volume ratio of the rubber solution to cyclohexane is 1 (10-40).
2. The high-stretch high-elasticity electromagnetic shielding composite material as claimed in claim 1, wherein: the hard rubber layer is set to be 90-100mm in length and 65-85mm in width; the spraying thickness is set to be 0.5-1 mu m when the soft rubber layer is prepared, and the spraying time is 1-5 s.
3. A method for preparing the high-stretch high-elasticity electromagnetic shielding composite material according to claim 1 or 2, wherein the method comprises the following steps: the method comprises the following specific steps:
(1) selection of the elastic substrate: selecting a hard rubber layer with the hardness of 50-70 HA, the length of 90-100mm and the width of 65-85mm as an elastic substrate;
(2) preparation of a bottom rubber layer: spraying a soft rubber layer on the elastic substrate in the step (1) as a bottom layer, wherein the bottom layer is detachably arranged; the soft rubber layer is obtained by dissolving a rubber solution in any one of solvents of cyclohexane, tetrahydrofuran, petroleum ether, hexane, pentane and isooctane; the rubber solution is prepared by mixing and hot melting white oil and SEBS according to the mass ratio of (5-7) to 1, wherein the dissolving mass-volume ratio of the rubber solution to cyclohexane is 1 (10-40);
(3) and (3) tensile deformation treatment: axially stretching the elastic substrate sprayed with the bottom rubber layer in the step (2) to 5-10 times of the original length and transversely stretching to 1-5 times of the original length according to the requirement;
(4) preparing a shielding layer: preparation of graphene coated nano Fe by coprecipitation method3O4The solution is used as a shielding layer, the shielding layer is sprayed on the surface of the composite substrate obtained in the step (3) by a spraying pump, and 1-5ml of ethanol is dripped on the surface of the shielding layer to completely soak the shielding layer;
(5) preparing a conductive layer: after the ethanol solvent in the step (4) is volatilized, spraying the graphene solution on the surface by using a spraying pump to form a graphene film, sputtering a layer of Ag nano particles on the graphene by using a magnetron sputtering method, and dripping 2-3ml of ethanol on the surface of the conducting layer to completely soak the conducting layer; after the ethanol solvent is volatilized, spraying a layer of soft rubber layer in the step (2) on the surface, and reducing the whole structure to the original size before the stretching after a period of time;
(6) preparing a dielectric layer: spraying a rubber solution on the surface of the structure obtained in the step (5) by using a spraying pump as a dielectric layer, wherein the rubber solution is the same as that in the step (2); wherein the pressure of the spray pump is 25-35psi, the spray pen is vertical to the surface to be sprayed, the distance between the spray pen and the surface to be sprayed is 9-20cm, the spray pen is moved left and right to spray uniformly;
wherein, the rubber solution is 200ml, and the thickness of the dielectric layer after spraying is set to any one of 3.5-6.5 microns, 8-12 microns, 13-16.5 microns and 18-22 microns;
(7) preparing a multilayer composite layer: repeating the steps (4) to (6) according to the requirement, and setting the number of the composite layers to be 50-100;
(8) and (5) after the step (7) is finished, removing the composite layer from the soft rubber layer of the elastic substrate to obtain the stable high-tensile high-elasticity electromagnetic shielding composite material.
4. The production method according to claim 3, characterized in that: in the step (4), nano Fe is coated by graphene3O4The solution is 100-210ml, the pressure of a spraying pump is 30-40psi, and a spray pen is vertical to the direction of the surface to be sprayed, wherein the distance between the spray pen and the surface to be sprayed is 5-20 cm; in the step (5), the graphene solution is obtained by firstly performing ultrasonic dispersion on graphene by using ethanol, and 50-210ml is adopted, wherein the volume mass-volume ratio of the ethanol to the graphene is (350-420) ml: 1g, and the ultrasonic time is 12-19 min; the graphene solution spraying method is the same as the spraying method of the dielectric layer in the step (6).
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5455117A (en) * | 1992-10-27 | 1995-10-03 | Kansai Paint Co., Ltd. | Electromagnetic wave reflection-preventing material and electromagnetic wave reflection-preventing method |
| CN105384146A (en) * | 2015-12-09 | 2016-03-09 | 唐山建华科技发展有限责任公司 | Graphene-loaded nanometer Fe<3>O<4>/ZnO composite and preparation method thereof |
| CN105555112A (en) * | 2016-01-22 | 2016-05-04 | 武汉理工大学 | Electromagnetic shielding composite material |
| CN107154282A (en) * | 2016-03-04 | 2017-09-12 | 江南石墨烯研究院 | Multilayer conductive elastic composite |
| CN206547250U (en) * | 2017-03-13 | 2017-10-10 | 东莞市鸿亿导热材料有限公司 | A kind of radiating graphite flake with electro-magnetic screen function |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102161785B (en) * | 2011-03-10 | 2013-02-13 | 四川大学 | Preparation method of graphene/polymer nano composite material |
| CN106211728B (en) * | 2016-07-10 | 2019-04-02 | 上海大学 | A kind of graphene coated Fe3O4The composite wave-suction material preparation method of nano particle |
| CN107799225B (en) * | 2016-08-29 | 2019-08-13 | 贝尔威勒电子股份有限公司 | High-frequency transmission cable |
| CN109553794A (en) * | 2018-11-23 | 2019-04-02 | 湖南国盛石墨科技有限公司 | A kind of flexible polyolefin film graphene electromagnetic shielding material and preparation method thereof |
| CN109627004B (en) * | 2018-12-19 | 2022-01-07 | 重庆大学 | Heat-conducting and electric-conducting graphene film and preparation method thereof |
| CN109777044B (en) * | 2019-02-25 | 2020-05-01 | 西北工业大学 | Electromagnetic shielding composite material based on graphene honeycomb structure and preparation method and application thereof |
-
2019
- 2019-06-04 CN CN201910479255.3A patent/CN110278702B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5455117A (en) * | 1992-10-27 | 1995-10-03 | Kansai Paint Co., Ltd. | Electromagnetic wave reflection-preventing material and electromagnetic wave reflection-preventing method |
| CN105384146A (en) * | 2015-12-09 | 2016-03-09 | 唐山建华科技发展有限责任公司 | Graphene-loaded nanometer Fe<3>O<4>/ZnO composite and preparation method thereof |
| CN105555112A (en) * | 2016-01-22 | 2016-05-04 | 武汉理工大学 | Electromagnetic shielding composite material |
| CN107154282A (en) * | 2016-03-04 | 2017-09-12 | 江南石墨烯研究院 | Multilayer conductive elastic composite |
| CN206547250U (en) * | 2017-03-13 | 2017-10-10 | 东莞市鸿亿导热材料有限公司 | A kind of radiating graphite flake with electro-magnetic screen function |
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