CN115891137A

CN115891137A - Method for 3D printing of electromagnetic shielding part with porous structure on basis of polyolefin elastomer

Info

Publication number: CN115891137A
Application number: CN202210302110.8A
Authority: CN
Inventors: 陈英红; 吕秦牛; 彭孜麟; 华正坤
Original assignee: Chengdu Pumeiyi Technology Co ltd; Sichuan University
Current assignee: Chengdu Pumeiyi Technology Co ltd; Sichuan University
Priority date: 2021-07-26
Filing date: 2022-03-24
Publication date: 2023-04-04
Also published as: CN113977932B; CN113478810A; CN113478810B; CN113977932A; CN114228139B; CN114228139A

Abstract

The invention provides a method for 3D printing of an electromagnetic shielding part with a porous structure based on a polyolefin elastomer, which comprises the steps of preparing a strand silk for 3D printing by extruding, processing and molding composite powder obtained by carrying out ultrasonic coating treatment or mixing treatment on polyolefin elastomer powder and carbon-based filler for electromagnetic shielding, and preparing the electromagnetic shielding part with the porous structure by a fusion deposition molding 3D printing technology. The electromagnetic shielding part can meet the requirements of electromagnetic shielding and heat dissipation, and the specific porous structure of the electromagnetic shielding part can endow the material with lower apparent density, further enhance the heat dissipation and improve the electromagnetic shielding performance under unit thickness-density. The method has the characteristics of continuous and automatic processing, short production period, multi-scale and multi-structure products, high personalized customization degree and the like.

Description

Method for 3D printing of electromagnetic shielding part with porous structure on basis of polyolefin elastomer

Technical Field

The invention belongs to the technical field of 3D printing electromagnetic shielding parts, particularly relates to a method for 3D printing electromagnetic shielding parts with porous structures on the basis of polyolefin elastomers, and particularly relates to a method for preparing a flexible gasket capable of synchronously realizing strong electromagnetic shielding and heat dissipation by adjusting the porosity of 3D printing.

Background

Communication devices and microelectronic devices based on information technology have been continuously updated since the third industrial revolution in the middle of the 20 th century. Meanwhile, various electromagnetic radiation and signal interference problems affect the health of the human body and the working accuracy of electronic equipment. In addition, the integration, miniaturization and increasing power density of electronic components can generate a great deal of waste heat, accelerate the aging of electronic equipment, and even cause fire hazards. Therefore, it is important to impart an electromagnetic shielding function and perform effective thermal management for improving the operational stability of the high-power electronic component. Metal materials have been used as the main EMI shielding and heat conducting materials due to their good electrical and thermal conductivity. However, the disadvantages of high density, harsh processing conditions and susceptibility to corrosion, as well as the dominant shielding mechanism for reflecting electromagnetic waves, limit the applications of metals in modern electronics. Polymer composites are the most promising materials in the modern electronics industry due to their low cost, ease of processing, corrosion resistance, ease of functionalization, and shielding mechanisms based on electromagnetic wave absorption. The compounding of polymers and high performance nanofillers (such as carbon nanotubes, graphene and MXene) has also become one of the common methods for electromagnetic shielding in industry.

Traditional polymer functional composites are typically prepared by compression molding, casting, foaming or freeze-drying processes, with functionalization being achieved by adjusting the structure of the nanofiller in the polymer matrix. However, as the shape of the electronic device is increasingly complex, the conventional processing technology cannot meet the requirement of rapid molding in modern industry, and the samples prepared by processing methods such as foaming and freeze drying cannot be applied to the fields of heat dissipation and large stress bearing, so that the development of the conventional processing method is limited. Due to the unique additional manufacturing technology of 3D printing, the adjustment and control of the performance can be realized through the adjustment of the material structure besides the realization of the diversity design of the material structure. Fused Deposition Modeling (FDM) is used as a 3D printing technology with high maturity and wide application field at present, and has the advantages of convenience in operation, rapidness in Modeling, intelligent slicing, low cost and the like. Controllable microstructures and programmable macrostructures are realized by 3D printing, which depicts a blueprint for practical application of composite materials. Materials suitable for FDM printing are developed in succession from general plastics to engineering plastics, such as rigid plastics like polylactic acid, polyamide, polyvinyl alcohol, polyvinylidene fluoride, polyetheretherketone, and the like. The hard plastics can be used as an electromagnetic shielding shell after being compounded with carbon nano-fillers. However, in the field of electromagnetic shielding liners and heat dissipation, these hard products cannot be well attached to a heat source, which requires development of an elastomer material favorable for FDM printing, thereby expanding the application field of 3D printing. In contrast, in recent years, FDM printing has been realized on flexible substrates such as thermoplastic polyurethane elastomers, and functionalization has been realized by compounding with carbon-based nanofillers. In order to meet the requirement of commercial electromagnetic shielding (20 dB), a large amount of functional filler is often required to be added, but after the filler is added, the mechanical property and the processing fluidity of the filler are deteriorated, so that the functional filler is accumulated in a printing nozzle to prevent the normal printing of the strand silk; and only a small amount of filler is added, the required shielding requirement is not met, and the printed elastomer does not have enough rigidity, can be curled and stacked in a pushing device, and can also influence the normal printing process. Therefore, the existing processing modes for realizing electromagnetic shielding usually adopt traditional modes such as pressing and casting, the processing mode is single, the production period is long, the shape can not be customized arbitrarily, the prepared solid product has a small specific surface area, and the timely and rapid heat dissipation of electronic components can not be realized, so that the processing mode has no substantial progress essentially. In order to better meet the requirements of microelectronic components in the field of modern electronic information, the required gasket needs to have excellent electromagnetic shielding performance and also needs to meet the requirements of the electronic components on convenient processing, random customization of shape and structure, better heat dissipation, good flexible fitting property and the like.

Therefore, the breakthrough of the technology is really realized, the defects of the traditional processing technology are overcome, the quality of preparing the porous electromagnetic shielding and heat dissipation gasket by the flexible polymer-based 3D printing technology is realized, and a great deal of difficulty still needs to be overcome. How to optimize the porous structure and performance of the material and essentially solve the challenges of high electromagnetic shielding and good heat dissipation of the material, so that the preparation of the 3D printing flexible polymer-based electromagnetic shielding and heat conducting gasket which meets the commercial electromagnetic shielding requirements and is customized is realized, and the difficulty and the key point of the urgent need of breakthrough in the prior art are the difficult points and the key points.

Disclosure of Invention

The invention aims to provide a method for 3D printing of an electromagnetic shielding part with a porous structure on the basis of a polyolefin elastomer, aiming at the defects of the prior art, the electromagnetic shielding part not only meets the requirements of electromagnetic shielding and heat dissipation, but also has a special porous structure, so that the material has lower apparent density, the heat dissipation performance can be further improved, and the electromagnetic shielding performance (EMI SSE/t) of unit product thickness-density is improved. The method has the characteristics of continuous and automatic processing, short production period, multi-scale and multi-structure products, high personalized customization degree and the like.

In order to achieve the purpose, the invention adopts the technical scheme formed by the following technical measures.

A method for 3D printing of an electromagnetic shielding part with a porous structure on the basis of a polyolefin elastomer comprises the following steps of:

(1) The preparation method comprises the steps of preparing materials including 75-95 parts of polyolefin elastomer powder and 5-25 parts of carbon-based filler for electromagnetic shielding, and then coating the carbon-based filler for electromagnetic shielding on the surface of the polyolefin elastomer powder through powder surface coating treatment to obtain composite powder coated with the carbon-based filler for electromagnetic shielding; or the polyolefin elastomer powder and the carbon-based filler for electromagnetic shielding are uniformly mixed, so that the carbon-based filler for electromagnetic shielding is uniformly dispersed in the polyolefin elastomer powder to form composite powder;

wherein the total amount of the polyolefin elastomer powder and the carbon-based filler for electromagnetic shielding is 100 parts;

(2) Extruding and processing the composite powder obtained in the step (1) to form silk strips for 3D printing; wherein the extrusion processing molding process parameters are as follows: the extrusion temperature is 10-50 ℃ higher than the melting temperature of the polyolefin elastomer powder, and the extrusion speed is 10-20 r/min;

(3) Putting the strand silk for 3D printing obtained in the step (2) into a fused deposition modeling 3D printer, and preparing an electromagnetic shielding part with a porous structure by a fused deposition modeling 3D printing technology; the fused deposition modeling 3D printing technology comprises the following process parameters: and (3) according to a three-dimensional digital model slice of a required piezoelectric product, arranging extruded strand wires to print along a filling mode of a straight line (Rectilinear), stacking and accumulating layer by layer with an internal filling angle of 0 DEG/90 DEG, wherein the internal filling density is 45-60%, the diameter of a nozzle is 1.0 +/-0.01 mm, the temperature of the printing nozzle is consistent with the extrusion temperature in the step (2), the temperature of a hot bed is 50-60 ℃, and the printing speed is 250-350 mm/min.

The main invention points of the invention are that: through a great deal of research and exploration of the inventor of the invention, the setting of the internal filling density, the regulation of the nozzle diameter and the limitation of the printing parameters during fused deposition modeling 3D printing are determined, so that the prepared electromagnetic shielding part has a three-dimensional porous structure characteristic, and the size of the holes, the distance between adjacent holes and the hole arrangement mode are standardized and quantized through the limiting conditions, so that the electromagnetic shielding and heat dissipation printing part with the porous structure, which is obviously superior to that of the prior art, is obtained. In addition, on the basis, through a large number of comparison experiments, the process conditions are further limited, and a person skilled in the art can prepare a product with better comprehensive performance (electromagnetic shielding performance, heat dissipation performance and mechanical performance, particularly reusability) or obtain an electromagnetic shielding multifunctional product with remarkable outstanding electromagnetic shielding performance according to the technical scheme of the invention.

It should be noted that, in principle, when the three-dimensional porous structure is printed by a filling mode in which fused deposition modeling 3D printing is performed to arrange extruded filaments along a straight line (Rectilinear), the filaments in the upper and lower layers are arranged along a printing filling angle of 0 °/90 ° and a filling density, so as to form macroscopic square holes with different sizes. When the printed article is solid, the packing density is set to 100%. The smaller the packing density, the larger the square pore size and the lower the mass of the filaments used. The inventor of the present invention found that the smaller the filling density is, the less the carbon-based filler for electromagnetic shielding added to the product is, and the electromagnetic shielding performance is liable to be lowered and the compressive strength is liable to be lowered. On the other hand, the smaller the packing density, the lower the apparent density of the product, and the higher the electromagnetic shielding value per unit thickness-density of the product, and when the packing density is reduced from 100% to 50%, the electromagnetic shielding value per unit thickness-density is from 155.9dB cm under the following preferred technical scheme conditions ² The/g rises to 244.9dB cm ² (iv) g. Meanwhile, the filling density is reduced, the pores are increased, the specific surface area of the workpiece is increased, the heat convection effect between the workpiece and air is enhanced, and the heat dissipation performance is also enhanced.

It should be noted that, through gradient contrast experiments, the inventors of the present invention found that, if a solid printed electromagnetic shielding article (i.e. at 100% packing density) is prepared according to a three-dimensional digital model of a traditional electromagnetic shielding article, the electromagnetic shielding performance of the obtained article meets the commercial electromagnetic shielding requirement, and the electromagnetic shielding value (EMI SE) of the obtained article is 31 to 34dB, but the electromagnetic shielding value (EMI SSE/t) per unit thickness-density is significantly lower than that of a porous structure, and is 155.9dB · cm ² (ii) in terms of/g. In addition, the thermal conductivity of the printed product at 100% packing density is increased to 1600% of that of the pure polyolefin elastomer, which is as high as 4.3W/(m.K), but the smaller specific surface area greatly reduces the thermal convection effect with air, and cannot realize the thermal convection effectThe best heat dissipation state. And the product at 100% packing density is tested to find that the rigidity is increased and the flexibility required by the cushion product is lost.

Generally, the polyolefin elastomer powder in step (1) is any one of thermoplastic elastomer polymers which can be used in fused deposition modeling 3D printing in the technical field, and those skilled in the art can select the polyolefin elastomer polymer powder which is recorded in the prior art or available on the market and can be used in fused deposition modeling 3D printing according to actual needs. To better illustrate the invention and provide a preferred embodiment, the polyolefin elastomer powder is selected from the group consisting of but not limited to dow chemical (U.S.) polyolefin elastomers Engage 8003, engage 8400, engage8450, or any of the other manufacturers and brands, and products having properties similar to the polyolefin elastomers described above.

Generally, the carbon-based filler for electromagnetic shielding in step (1) is selected from carbon-based fillers which are described in the prior art or are conventionally added in polymer-based electromagnetic shielding materials or products in the technical field and have the electromagnetic shielding function. The carbon-based filler for electromagnetic shielding preferably comprises one or more of carbon nanotubes, carbon black, graphite, graphene and carbon fibers.

In the step (1), in order to coat the carbon-based filler for electromagnetic shielding on the surface of the polyolefin elastomer powder, a person skilled in the art can refer to the existing powder surface coating treatment technology and perform the treatment according to actual conditions. In order to better illustrate the invention and provide a preferable technical scheme, the powder surface coating treatment adopts a solution ultrasonic coating method, specifically, polyolefin elastomer powder and carbon-based filler for electromagnetic shielding are subjected to ultrasonic treatment in ethanol solution, stirred and dispersed, then kept stand to enable the carbon-based filler for electromagnetic shielding to coat the surface of the powder of the polyolefin elastomer powder, filtered and dried to obtain composite powder coated with the carbon-based filler for electromagnetic shielding; wherein the technological parameters of the solution ultrasonic coating method are as follows: the ultrasonic power is 800W-1000W, and the ultrasonic time is 1.5-2 h; the stirring speed is 450-600 r/min.

Wherein, the step (1) of uniformly mixing the polyolefin elastomer powder with the carbon-based filler for electromagnetic shielding to uniformly disperse the carbon-based filler for electromagnetic shielding in the polyolefin elastomer powder, and the selection usually comprises uniform mixing under the action of mechanochemistry, and comprises any one of a millform solid-phase mechanochemical reactor, a high-speed mixer and a ball mill.

It should be noted that, the composite powder obtained in step (1) is directly extruded and molded to prepare the 3D printing filament, mainly to enable the carbon-based filler for electromagnetic shielding to be uniformly dispersed in the 3D printing filament, but through comparative experiments by the inventors, it is found that, in actual production, the powder surface coating treatment is more beneficial to the formation of a uniform filler network by the carbon-based filler for electromagnetic shielding. Therefore, the polyolefin elastomer powder and the carbon-based filler for electromagnetic shielding are uniformly mixed, if the polyolefin elastomer powder and the carbon-based filler for electromagnetic shielding can be sufficiently and uniformly mixed, theoretically, the powder surface coating treatment is equivalent to the powder surface coating treatment, but in an actual production link, the theoretical effect is difficult to achieve, and the electromagnetic shielding performance and the mechanical performance of the prepared electromagnetic shielding part are obviously inferior to the technical scheme of the powder surface coating treatment.

Generally, the extrusion molding in step (2) is a conventional extrusion molding process in the prior art, including twin-screw melt extrusion molding and single-screw melt extrusion molding.

Generally, in the fused deposition modeling 3D printing technique in step (3), besides the process parameters defined in the technical solution, other process parameters may refer to conventional 3D printing process parameters in the art, and those skilled in the art may select appropriate process parameters according to specific 3D printing processing conditions and according to the characteristics of the polyolefin elastomer-based material and referring to the prior art.

It is important to note that the control of the temperature of the showerhead in step (3) is particularly important. The filling density in the printing parameters of the invention is lower than 100%, if the temperature of the spray head is too high, the fluidity of the strand silk is too strong, and the strand silk is easy to collapse into the gap between the next layer of strand silk, so that the whole product can not be molded; if the temperature of the spray head is too low, the strand silk is infusible or poor in fluidity, and printing cannot be performed.

It is important to note that the control of the nozzle diameter and the printing rate in step (3) is particularly important. The material used in the present invention is a polyolefin elastomer with excellent flexibility, while FDM printing has some degree of shear and extrusion pressure due to narrowing of the flow channel. Too small a nozzle diameter and too fast a printing speed make it difficult to extrude the filament for printing.

It is important to point out that the hot bed temperature range in step (3) is limited to 50-60 deg.C, under this condition, the product with high dimensional stability and without obvious warpage can be prepared. When the temperature is lower than the limited temperature range, the strand silk cannot be rapidly cooled and solidified, the deposited strand silk is easy to warp and deform in the process of printing the product, and the printing of the electromagnetic shielding product, particularly the printing of a multilayer product with a larger size cannot be smoothly finished; when the temperature is higher than the limited temperature range, although the filaments of the upper layer and the lower layer are well bonded, the deposited filaments are in a softened state because of the inability to cool rapidly, and are easily driven by the moving spray head.

In general, other processing aids such as antioxidants, flame retardants, antioxidants and the like known in the art may also be added to the present invention. However, it is a prerequisite that these processing aids do not adversely affect the achievement of the objects of the present invention and the achievement of the advantageous effects of the present invention.

However, it is further important to point out that in the actual preparation process, the specific selection based on the polyolefin elastomer powder and the carbon-based filler for electromagnetic shielding will inevitably change the mechanical properties and electromagnetic shielding properties of the prepared electromagnetic shielding product, so that based on the inventive principle, the optimum internal filling density will inevitably vary with the different raw materials. However, it should be clear to those skilled in the art that the above inventive principles are broadly applicable to any selection of polyolefin elastomer powder and carbon-based filler for electromagnetic shielding that can be used in fused deposition modeling 3D printing technology, and the electromagnetic shielding and heat dissipation performance per unit thickness-density of the prepared electromagnetic shielding component are significantly better than those of solid components, and can meet the requirements of commercial electromagnetic shielding.

Meanwhile, with specific selection of polyolefin elastomer powder and carbon-based filler for electromagnetic shielding, and setting of internal filling density during fused deposition modeling 3D printing, specification of nozzle diameter and selection of printing parameters, although a part prepared from the carbon-based filler has good performance in electromagnetic shielding value (EMI SSE/t) per unit thickness-density, with great reduction of density of the material of the part, it is unknown and unpredictable whether the part has sufficient mechanical properties to meet practical application standards. This is because the cellular structure shows an extremely regular and uniform rectangular pore structure in the actual product, which is significantly different from the non-uniform spherical pore structure of the prior art that usually adopts foaming technology to obtain the cellular structure, and the mechanical properties of the cellular structure in three-dimensional space cannot be directly referred to the foamed product of the same material, so that the mechanical properties of the obtained product need to be further explored and optimized within the above-defined internal filling density range.

Therefore, in order to obtain a product with better comprehensive performance (electromagnetic shielding performance, heat dissipation performance and mechanical performance, particularly reusability), the invention adopts the following preferred technical scheme in practical experiments and embodiments. It is emphasized that the following detailed description is not intended to be exhaustive or to limit the invention to the precise form disclosed, and the inventive principles and advantages are well understood.

A method for 3D printing of an electromagnetic shielding part with a porous structure on the basis of a polyolefin elastomer comprises the following steps in parts by weight:

preparing materials comprising 77-80 parts of polyolefin elastomer powder and 20-23 parts of carbon-based filler for electromagnetic shielding, and coating the carbon-based filler for electromagnetic shielding on the surface of the polyolefin elastomer powder by a solution ultrasonic coating method to obtain composite powder coated with the carbon-based filler for electromagnetic shielding;

the polyolefin elastomer powder is a Dow chemical (American) polyolefin elastomer Engage8450;

the carbon-based filler for electromagnetic shielding is graphene;

(II) extruding and processing the composite powder obtained in the step (I) to form threads for 3D printing; wherein, the extrusion processing molding process parameters are as follows: the extrusion temperature is 10-50 ℃ higher than the melting temperature of the polyolefin elastomer powder, and the extrusion speed is 10-20 r/min;

(III) putting the strand silk for 3D printing obtained in the step (II) into a fused deposition modeling 3D printer, and preparing the electromagnetic shielding part with the porous structure by a fused deposition modeling 3D printing technology; the fused deposition modeling 3D printing technology comprises the following process parameters: slicing according to a three-dimensional digital model of a required piezoelectric product, arranging extruded strand silk, and printing along a filling mode of a straight line (Recilinear), wherein the internal filling angle is 0 DEG/90 DEG, stacking and accumulating layer by layer, the internal filling density is 45-55%, the diameter of a nozzle is 1.0 +/-0.01 mm, the temperature of the printing nozzle is consistent with the extrusion temperature in the step (2), the temperature of a hot bed is 50-60 ℃, and the printing speed is 250-350 mm/min.

Based on the above preferred technical solution, it should be further explained that after the selection and the ratio of the polyolefin elastomer powder and the carbon-based filler for electromagnetic shielding are determined, that is, the material of the product has consistent mechanical properties, a gradient experiment shows that, as the internal filling density is continuously reduced, the electromagnetic shielding value and the compressive strength of the product exhibit two reduction stages: the performance is slowly reduced under 100-50% of internal filling density; when the internal filling density is lower than 50%, the performance is rapidly reduced, and the transition region is in the range of 45-55%. In addition, the maximum value of the electromagnetic shielding value per unit thickness-density of the product is 45-55% on the premise that the electromagnetic shielding value is higher than the commercial requirement (20 dB). The heat dissipation properties of the article also increase as the packing density decreases. In comprehensive consideration, the internal filling density is further preferably 50-55%, and the corresponding printed product has excellent electromagnetic shielding property, heat dissipation property and mechanical property, and the comprehensive property reaches the best. It should be noted that, in the preferred technical solution, the selection and the specific limitation of the ratio of the polyolefin elastomer powder and the carbon-based filler for electromagnetic shielding are used to achieve the coincidence of the transition region of the mechanical property of the electromagnetic shielding part and the optimal region of the electromagnetic shielding property, so that the electromagnetic shielding part has the optimal electromagnetic shielding property, and simultaneously has the better mechanical property and the optimal comprehensive property.

It should be further noted that, under the above preferred technical solution, the limitation that the carbon-based filler for electromagnetic shielding is graphene in step (i) is exclusively limited, because the specific selection and addition amount of the carbon-based filler for electromagnetic shielding significantly affects the formation of the network of the electrically and thermally conductive filler in the polyolefin elastomer matrix, and thus affects the electromagnetic shielding performance and heat dissipation performance of the product. Carbon black, graphite and carbon fiber have no excellent electromagnetic shielding and heat conducting capacity and are easy to cause agglomeration in a matrix; the one-dimensional carbon nanotube has excellent electromagnetic shielding capability, but relatively weak heat transfer capability. In order to realize good electromagnetic shielding and thermal conductivity and realize good dispersion and coating of the carbon-based filler on the surface of the polyolefin elastomer powder, graphene which has excellent electromagnetic shielding and thermal conductivity and has a large specific surface is selected and used. Therefore, in a preferred embodiment, the carbon-based filler for electromagnetic shielding is graphene.

Furthermore, the limitation of the solution ultrasonic coating method in step (i) is an exclusive limitation, because the polyolefin elastomer is used as a thermoplastic elastomer, the glass transition temperature of the polyolefin elastomer is far lower than room temperature, and the high-strength mechanochemical technology and high-speed mixing can only achieve the dispersion of the carbon-based filler, but cannot achieve better coating, which is not beneficial to constructing a better filler electric and heat conducting network; the ball mill generates a large amount of heat in the operation process, so that the polyolefin elastomer is easily bonded. Therefore, the solution ultrasonic coating method is limited in the preferred technical scheme based on the problems of the actual process.

The invention has the following beneficial effects:

1. according to the invention, the filler is loaded on the surface of the polymer particles by a solution ultrasonic coating method, and then the 3D printing filament is prepared by extrusion under a specific extrusion condition, so that the commercial standard of electromagnetic shielding can be realized under the condition of proper filler content; the 3D printing strand silk with excessively high filler content is prevented from blocking the printing nozzle, so that the printing performance of the printing strand silk is reduced; the rigidity of the elastomer material is improved in a fixed degree, the phenomenon that filament yarns are stacked and curled in a pushing device due to overhigh flexibility is avoided, and the technical problem of high shielding performance-low printing performance existing in the prior art for preparing and printing the elastomer filament yarns is directly solved;

2. the invention determines the setting of the internal filling density, the regulation of the nozzle diameter and the limitation of the printing parameters during 3D printing of fused deposition modeling based on experimental evidence, so that the prepared electromagnetic shielding and heat dissipation part has the characteristics of a three-dimensional porous structure, the size of the holes, the distance between adjacent holes and the hole arrangement mode are standardized and quantized through the limiting conditions, and the electromagnetic shielding part has better electromagnetic shielding performance per unit thickness-density and heat dissipation performance than the conventional electromagnetic shielding part with 100% filling density through exploration and research on the porous structure.

3. The invention realizes the personalized customization of the electromagnetic shielding and heat dissipation gasket with multiple sizes and structures by utilizing the 3D printing thread line, has simple production process, easy operation and strong personalized design, can meet the customization requirements of electronic devices with different sizes and structures, has wide application and convenient popularization, and directly solves the defects of single design structure, long period and high cost in the traditional electromagnetic shielding gasket preparation process (mold design-casting molding-fine processing).

4. The electromagnetic shielding and heat dissipation gasket is prepared by using the 3D printing silk strips, full-automatic and continuous production can be completely realized on the basis of the existing commercial 3D printing equipment, the electromagnetic shielding and heat dissipation gasket with a complex structure is formed at one time from personalized modeling, a printer is not required to be improved, additional equipment is not required to be added, the application of FDM printing in the electric and thermal fields is expanded, and the commercial popularization advantage is obvious.

Drawings

Fig. 1 is a scanning electron microscope (left image) of a composite powder in which a carbon-based filler for electromagnetic shielding is coated on the surface in examples 1 to 4 and comparative examples 1 to 6, and a scanning electron microscope (right image) of a cross section of a filament for 3D printing obtained by extrusion molding the composite powder. The result shows that the graphene is uniformly coated on the surface of the polyolefin elastomer, and a graphene network structure is successfully constructed, so that the propagation of electrons and phonons is facilitated, and the electromagnetic shielding and heat dissipation properties are further improved.

Fig. 2 is a graph showing the comparison of the electromagnetic shielding performance of the electromagnetic shielding articles prepared in examples 1 to 4 and comparative examples 1 to 6.

Fig. 3 is a graph showing the electromagnetic shielding performance per unit thickness-density of the electromagnetic shielding articles prepared in examples 1 to 4 and comparative examples 1 to 6. It should be noted that the data selected in fig. 3 only refers to the data with higher electromagnetic shielding values than commercial shielding values in the entire X-band, and therefore only data with a filling density of 45% or more is used. The result shows that the commercial requirement of the electromagnetic shielding ventilating board can be met when the electromagnetic shielding performance of the porous electromagnetic shielding gasket prepared by the method reaches more than 45 percent of filling density; and in the range of the filling density of 45-55%, the electromagnetic shielding performance of unit thickness-density is the highest and is far higher than that of a solid gasket under the filling density of 100%.

Fig. 4 is an infrared thermal image of the electromagnetic shielding device with porous structure prepared in example 2 in a heat dissipation test.

Fig. 5 is a graph of the temperature decrease of the electromagnetic shielding device with a porous structure prepared in example 2 in the heat dissipation test. Obviously, the electromagnetic shielding part with the porous structure has a much faster heat dissipation rate than the solid electromagnetic shielding part.

Fig. 6 is a graph comparing the compression performance of the electromagnetic shielding members prepared in examples 1 to 4 and comparative examples 1 to 6, which were subjected to 500 cycles of compression at a strain of 5%. Obviously, the maximum compressive stress of the cyclic compression is slowly reduced to the range of 45-55% along with the reduction of the filling density, and the mechanical property is greatly reduced after the filling density is lower than the range.

Fig. 7 is a photograph (left image) of the electromagnetic shielding device with a porous structure prepared in example 2 and a microscopic morphology image (right image) thereof.

Detailed Description

The invention is further illustrated by the following examples in conjunction with the accompanying drawings. It should be noted that the examples given are not to be construed as limiting the scope of the invention, and that those skilled in the art, on the basis of the teachings of the present invention, will be able to make numerous insubstantial modifications and adaptations of the invention without departing from its scope.

It should be noted that Agilent N5230A vector network analyzer is adopted for testing the electromagnetic shielding performance in the examples and comparative examples, and the test wave band is 8.2-12.4 GHz.

It should be noted that the heat dissipation performance tests of the examples and the comparative examples pass the Testo 870-2 infrared thermal imager, and the observation process is a cooling test.

It should be noted that the compression performance test of the examples and the comparative examples is performed by a Bose dynamic/static mechanical tester (Bose 3220SERIES II), and the compression rate is 10mm/min.

Comparative example 1

The method for 3D printing of the electromagnetic shielding part with the porous structure based on the polyolefin elastomer comprises the following steps of:

preparing materials comprising 77 parts of polyolefin elastomer powder and 23 parts of carbon-based filler for electromagnetic shielding, and coating the carbon-based filler for electromagnetic shielding on the surface of the polyolefin elastomer powder by a solution ultrasonic coating method to obtain composite powder coated with the carbon-based filler for electromagnetic shielding;

the carbon-based filler for electromagnetic shielding is graphene;

the solution ultrasonic coating method specifically comprises the steps of carrying out ultrasonic and stirring dispersion on polyolefin elastomer powder and carbon fillers for electromagnetic shielding in an ethanol solution, standing to ensure that the carbon fillers for electromagnetic shielding are coated on the surface of the polyolefin elastomer powder, filtering and drying to obtain composite powder coated with the carbon fillers for electromagnetic shielding; wherein the technological parameters of the solution ultrasonic coating method are as follows: the ultrasonic power is 1000W, and the ultrasonic time is 1.5h; the stirring rate was 500r/min.

(II) extruding and processing the composite powder obtained in the step (I) to form threads for 3D printing; wherein, the extrusion processing molding process parameters are as follows: the extrusion temperature is 50 ℃ higher than the melting temperature of the polyolefin elastomer powder, and the extrusion speed is 15r/min;

(III) putting the strand silk for 3D printing obtained in the step (II) into a fused deposition modeling 3D printer, and preparing the electromagnetic shielding part with the porous structure by a fused deposition modeling 3D printing technology; the fused deposition modeling 3D printing technology comprises the following process parameters: and (3) slicing according to a three-dimensional digital model of a required piezoelectric product, arranging extruded strand wires to print along a filling mode of a straight line (Recilinear), stacking and accumulating layer by layer with an internal filling angle of 0 DEG/90 DEG, wherein the internal filling density is 35%, the diameter of a nozzle is 1.0 +/-0.01 mm, the temperature of the printing nozzle is consistent with the extrusion temperature in the step (2), the temperature of a hot bed is 50 ℃, and the printing speed is 250mm/min.

Through tests, the prepared electromagnetic shielding part with the porous structure has the electromagnetic shielding value (EMI SSE/t) of 270.0dB cm under the unit thickness-density ² The maximum compressive stress of cyclic compression is reduced from 765KPa to 700KPa at 500 times of 5% deformation, but the electromagnetic shielding values of the X band are not all higher than the commercial shielding (20 dB).

It should be noted that the X band is a wide-range band of 8.2 to 12.4GHz, which is referred to in the common general knowledge in the art, and the above-mentioned meaning that the total electromagnetic shielding value of the electromagnetic shielding component has a region lower than 20dB in this band range, and the following description is omitted.

The thickness of the prepared electromagnetic shielding part is 2mm, and the same is applied below.

Comparative example 2

the carbon-based filler for electromagnetic shielding is graphene;

(III) putting the strand silk for 3D printing obtained in the step (II) into a fused deposition modeling 3D printer, and preparing the electromagnetic shielding part with the porous structure by a fused deposition modeling 3D printing technology; the fused deposition modeling 3D printing technology comprises the following process parameters: and (3) according to a three-dimensional digital model slice of a required piezoelectric product, arranging extruded strand wires to print along a filling mode of a straight line (Rectilinear), stacking and accumulating layer by layer with an internal filling angle of 0 DEG/90 DEG, wherein the internal filling density is 40%, the diameter of a nozzle is 1.0 +/-0.01 mm, the temperature of the printing nozzle is consistent with the extrusion temperature in the step (2), the temperature of a hot bed is 50 ℃, and the printing speed is 250mm/min.

Tests show that the electromagnetic shielding part with the porous structure has an electromagnetic shielding value (EMI SSE/t) of 247.2dB cm under unit thickness-density ² The maximum compressive stress of the cyclic compression is reduced from 804KPa to 747KPa at 500 deformation amounts, but the electromagnetic shielding values in the X band range are not all higher than the commercial shielding (20 dB) requirements.

Example 1

The embodiment of the invention relates to a method for 3D printing of an electromagnetic shielding part with a porous structure on the basis of a polyolefin elastomer, which comprises the following steps of:

preparing materials comprising 77 parts of polyolefin elastomer powder and 23 parts of carbon-based filler for electromagnetic shielding, and then coating the carbon-based filler for electromagnetic shielding on the surface of the polyolefin elastomer powder by a solution ultrasonic coating method to obtain composite powder coated with the carbon-based filler for electromagnetic shielding;

the carbon-based filler for electromagnetic shielding is graphene;

the solution ultrasonic coating method comprises the steps of performing ultrasonic treatment on polyolefin elastomer powder and carbon fillers for electromagnetic shielding in an ethanol solution, stirring and dispersing, standing to coat the carbon fillers for electromagnetic shielding on the surface of the polyolefin elastomer powder, filtering and drying to obtain composite powder coated with the carbon fillers for electromagnetic shielding; the process parameters of the solution ultrasonic coating method are as follows: the ultrasonic power is 1000W, and the ultrasonic time is 1.5h; the stirring rate was 500r/min.

(III) putting the strand silk for 3D printing obtained in the step (II) into a fused deposition modeling 3D printer, and preparing the electromagnetic shielding part with the porous structure by a fused deposition modeling 3D printing technology; the fused deposition modeling 3D printing technology comprises the following process parameters: and (3) slicing according to a three-dimensional digital model of a required piezoelectric product, arranging extruded strand wires to print along a filling mode of a straight line (Recilinear), stacking and accumulating layer by layer with an internal filling angle of 0 DEG/90 DEG, wherein the internal filling density is 45%, the diameter of a nozzle is 1.0 +/-0.01 mm, the temperature of the printing nozzle is consistent with the extrusion temperature in the step (2), the temperature of a hot bed is 50 ℃, and the printing speed is 250mm/min.

Through tests, the prepared electromagnetic shielding part with the porous structure has the electromagnetic shielding value (EMI SSE/t) of 244.5dB cm under the unit thickness-density ² At 500 times of 5% deformation, the maximum compressive stress of the cyclic compression drops from 959KPa to 907KPa.

Example 2

the carbon-based filler for electromagnetic shielding is graphene;

the solution ultrasonic coating method comprises the steps of performing ultrasonic treatment on polyolefin elastomer powder and carbon fillers for electromagnetic shielding in an ethanol solution, stirring and dispersing, standing to coat the carbon fillers for electromagnetic shielding on the surface of the polyolefin elastomer powder, filtering and drying to obtain composite powder coated with the carbon fillers for electromagnetic shielding; wherein the technological parameters of the solution ultrasonic coating method are as follows: the ultrasonic power is 1000W, and the ultrasonic time is 1.5h; the stirring rate was 500r/min.

(III) putting the strand silk for 3D printing obtained in the step (II) into a fused deposition modeling 3D printer, and preparing the electromagnetic shielding part with the porous structure by a fused deposition modeling 3D printing technology; the fused deposition modeling 3D printing technology comprises the following process parameters: and (3) according to a three-dimensional digital model slice of a required piezoelectric product, arranging extruded strand wires to print along a filling mode of a straight line (Rectilinear), stacking and accumulating layer by layer with an internal filling angle of 0 DEG/90 DEG, wherein the internal filling density is 50%, the diameter of a nozzle is 1.0 +/-0.01 mm, the temperature of the printing nozzle is consistent with the extrusion temperature in the step (2), the temperature of a hot bed is 50 ℃, and the printing speed is 250mm/min.

Through tests, the prepared electromagnetic shielding part with the porous structure has the electromagnetic shielding value (EMI SSE/t) of 244.9dB cm under the unit thickness-density ² At 500 times of 5% deformation, the maximum compressive stress of the cyclic compression drops from 1202KPa to 1157KPa.

Example 3

The embodiment of the invention provides a method for 3D printing of an electromagnetic shielding part with a porous structure based on a polyolefin elastomer, which comprises the following steps in parts by weight:

the carbon-based filler for electromagnetic shielding is graphene;

(III) putting the strand silk for 3D printing obtained in the step (II) into a fused deposition modeling 3D printer, and preparing the electromagnetic shielding part with the porous structure by a fused deposition modeling 3D printing technology; the fused deposition modeling 3D printing technology comprises the following process parameters: and (3) according to a three-dimensional digital model slice of a required piezoelectric product, arranging extruded strand wires to print along a filling mode of a straight line (Rectilinear), stacking and accumulating layer by layer with an internal filling angle of 0 DEG/90 DEG, wherein the internal filling density is 55%, the diameter of a nozzle is 1.0 +/-0.01 mm, the temperature of the printing nozzle is consistent with the extrusion temperature in the step (2), the temperature of a hot bed is 50 ℃, and the printing speed is 250mm/min.

Through tests, the prepared electromagnetic shielding part with the porous structure has the electromagnetic shielding value (EMI SSE/t) of 226.6dB cm under the unit thickness-density ² At 500 times 5% deformation, the maximum compressive stress of cyclic compression drops from 1232KPa to 1178KPa.

Example 4

the carbon-based filler for electromagnetic shielding is graphene;

(III) putting the strand silk for 3D printing obtained in the step (II) into a fused deposition modeling 3D printer, and preparing the electromagnetic shielding part with the porous structure by a fused deposition modeling 3D printing technology; the fused deposition modeling 3D printing technology comprises the following process parameters: and (3) according to a three-dimensional digital model slice of a required piezoelectric product, arranging extruded strand wires to print along a filling mode of a straight line (Rectilinear), stacking and accumulating layer by layer with an internal filling angle of 0 DEG/90 DEG, wherein the internal filling density is 60%, the diameter of a nozzle is 1.0 +/-0.01 mm, the temperature of the printing nozzle is consistent with the extrusion temperature in the step (2), the temperature of a hot bed is 50 ℃, and the printing speed is 250mm/min.

Through tests, the prepared electromagnetic shielding part with the porous structure has the electromagnetic shielding value (EMI SSE/t) of 211.6dB cm under the unit thickness-density ² At 500 times of 5% deformation, the maximum compressive stress of the cyclic compression drops from 1283KPa to 1201KPa.

Comparative example 3

the carbon-based filler for electromagnetic shielding is graphene;

(III) putting the strand silk for 3D printing obtained in the step (II) into a fused deposition modeling 3D printer, and preparing the electromagnetic shielding part with the porous structure by a fused deposition modeling 3D printing technology; the fused deposition modeling 3D printing technology comprises the following process parameters: and (3) according to a three-dimensional digital model slice of a required piezoelectric product, arranging extruded strand wires to print along a filling mode of a straight line (Rectilinear), stacking and accumulating layer by layer with an internal filling angle of 0 DEG/90 DEG, wherein the internal filling density is 70%, the diameter of a nozzle is 1.0 +/-0.01 mm, the temperature of the printing nozzle is consistent with the extrusion temperature in the step (2), the temperature of a hot bed is 50 ℃, and the printing speed is 250mm/min.

Through tests, the prepared electromagnetic shielding part with the porous structure has the electromagnetic shielding value (EMI SSE/t) of 190.8dB cm under the unit thickness-density ² At 500 times of 5% deformation, the maximum compressive stress of cyclic compression drops from 1465KPa to 1343KPa.

Comparative example 4

The method for 3D printing of the electromagnetic shielding part with the porous structure based on the polyolefin elastomer comprises the following steps in parts by weight:

the carbon-based filler for electromagnetic shielding is graphene;

(III) putting the strand silk for 3D printing obtained in the step (II) into a fused deposition modeling 3D printer, and preparing the electromagnetic shielding part with the porous structure by a fused deposition modeling 3D printing technology; the fused deposition modeling 3D printing technology comprises the following process parameters: and (3) according to a three-dimensional digital model slice of a required piezoelectric product, arranging extruded strand wires to print along a filling mode of a straight line (Rectilinear), stacking and accumulating layer by layer with an internal filling angle of 0 DEG/90 DEG, wherein the internal filling density is 80%, the diameter of a nozzle is 1.0 +/-0.01 mm, the temperature of the printing nozzle is consistent with the extrusion temperature in the step (2), the temperature of a hot bed is 50 ℃, and the printing speed is 250mm/min.

Through tests, the electromagnetic shielding part with the porous structure is prepared, and the electromagnetic shielding value (EMI SSE/t) under the unit thickness-density is 179.1dB cm ² At 500 times of 5% deformation, the maximum compressive stress of the cyclic compression is reduced from 1567KPa to 1522KPa.

Comparative example 5

the carbon-based filler for electromagnetic shielding is graphene;

(III) putting the strand silk for 3D printing obtained in the step (II) into a fused deposition modeling 3D printer, and preparing the electromagnetic shielding part with the porous structure by a fused deposition modeling 3D printing technology; the fused deposition modeling 3D printing technology comprises the following process parameters: and (3) according to a three-dimensional digital model slice of a required piezoelectric product, arranging extruded strand wires to print along a filling mode of a straight line (Rectilinear), stacking and accumulating layer by layer with an internal filling angle of 0 DEG/90 DEG, wherein the internal filling density is 90%, the diameter of a nozzle is 1.0 +/-0.01 mm, the temperature of the printing nozzle is consistent with the extrusion temperature in the step (2), the temperature of a hot bed is 50 ℃, and the printing speed is 250mm/min.

Through tests, the prepared electromagnetic shielding part with the porous structure has the electromagnetic shielding value (EMI SSE/t) of 164.8dB cm under the unit thickness-density ² At 500 times of 5% deformation, the maximum compressive stress of cyclic compression drops from 1625KPa to 1594KPa.

Comparative example 6

The method for 3D printing of the electromagnetic shielding part based on the polyolefin elastomer comprises the following steps of:

the carbon-based filler for electromagnetic shielding is graphene;

(III) putting the strand silk for 3D printing obtained in the step (II) into a fused deposition modeling 3D printer, and preparing an electromagnetic shielding part by a fused deposition modeling 3D printing technology; the fused deposition modeling 3D printing technology comprises the following process parameters: and (3) slicing according to a three-dimensional digital model of a required piezoelectric product, arranging extruded strand wires to print along a filling mode of a straight line (Recilinear), stacking and accumulating layer by layer with an internal filling angle of 0 DEG/90 DEG, wherein the internal filling density is 100%, the diameter of a nozzle is 1.0 +/-0.01 mm, the temperature of the printing nozzle is consistent with the extrusion temperature in the step (2), the temperature of a hot bed is 50 ℃, and the printing speed is 250mm/min.

The electromagnetic shielding product obtained by the test has an electromagnetic shielding value (EMI SSE/t) of 153.9dB cm under unit thickness-density ² At 500 times of 5% deformation, the maximum compressive stress of cyclic compression drops from 1677KPa to 1634KPa.

Example 5

preparing materials comprising 95 parts of polyolefin elastomer powder and 5 parts of carbon-based filler for electromagnetic shielding, and coating the carbon-based filler for electromagnetic shielding on the surface of the polyolefin elastomer powder by a solution ultrasonic coating method to obtain composite powder coated with the carbon-based filler for electromagnetic shielding;

the polyolefin elastomer powder is a Dow chemical (American) polyolefin elastomer Engage 8003;

the carbon series filler for electromagnetic shielding is a carbon nano tube;

(II) extruding and processing the composite powder obtained in the step (I) to form threads for 3D printing; wherein, the extrusion processing molding process parameters are as follows: the extrusion temperature is 20 ℃ higher than the melting temperature of the polyolefin elastomer powder, and the extrusion speed is 15r/min;

Example 6

preparing materials comprising 90 parts of polyolefin elastomer powder and 10 parts of carbon-based filler for electromagnetic shielding, and then uniformly mixing the polyolefin elastomer powder and the carbon-based filler for electromagnetic shielding to ensure that the carbon-based filler for electromagnetic shielding is uniformly dispersed in the polyolefin elastomer powder to form composite powder;

the carbon-based filler for electromagnetic shielding is graphene;

in the embodiment, a millform solid-phase mechanochemical reactor is selected and adopted, which can refer to the mechanochemical reactor disclosed in ZL95111258.9 and the use guidance in the relevant patent documents.

(II) extruding and processing the composite powder obtained in the step (I) to form threads for 3D printing; wherein, the extrusion processing molding process parameters are as follows: the extrusion temperature is 30 ℃ higher than the melting temperature of the polyolefin elastomer powder, and the extrusion speed is 15r/min;

(III) putting the strand silk for 3D printing obtained in the step (II) into a fused deposition modeling 3D printer, and preparing the electromagnetic shielding part with the porous structure by a fused deposition modeling 3D printing technology; the fused deposition modeling 3D printing technology comprises the following process parameters: and (3) slicing according to a three-dimensional digital model of a required piezoelectric product, arranging extruded strand wires to print along a filling mode of a straight line (Recilinear), stacking and accumulating layer by layer with an internal filling angle of 0 DEG/90 DEG, wherein the internal filling density is 50%, the diameter of a nozzle is 1.0 +/-0.01 mm, the temperature of the printing nozzle is consistent with the extrusion temperature in the step (2), the temperature of a hot bed is 50 ℃, and the printing speed is 250mm/min.

Example 7

preparing materials comprising 85 parts of polyolefin elastomer powder and 15 parts of carbon-based filler for electromagnetic shielding, and then coating the carbon-based filler for electromagnetic shielding on the surface of the polyolefin elastomer powder by a solution ultrasonic coating method to obtain composite powder coated with the carbon-based filler for electromagnetic shielding;

the polyolefin elastomer powder is a Dow chemical (American) polyolefin elastomer Engage 8400;

the carbon-based filler for electromagnetic shielding is carbon fiber;

(II) extruding and processing the composite powder obtained in the step (I) to form threads for 3D printing; wherein, the extrusion processing molding process parameters are as follows: the extrusion temperature is 40 ℃ higher than the melting temperature of the polyolefin elastomer powder, and the extrusion speed is 15r/min;

Claims

1. A method for 3D printing of an electromagnetic shielding part with a porous structure based on a polyolefin elastomer is characterized by comprising the following steps in parts by weight:

(1) Preparing materials comprising 75-95 parts of polyolefin elastomer powder and 5-25 parts of carbon-based filler for electromagnetic shielding, and coating the carbon-based filler for electromagnetic shielding on the surface of the polyolefin elastomer powder through powder surface coating treatment to obtain composite powder coated with the carbon-based filler for electromagnetic shielding; or the polyolefin elastomer powder and the carbon-based filler for electromagnetic shielding are uniformly mixed, so that the carbon-based filler for electromagnetic shielding is uniformly dispersed in the polyolefin elastomer powder to form composite powder;

(2) Extruding and processing the composite powder obtained in the step (1) to form silk strips for 3D printing; wherein, the extrusion processing molding process parameters are as follows: the extrusion temperature is 10-50 ℃ higher than the melting temperature of the polyolefin elastomer powder, and the extrusion speed is 10-20 r/min;

(3) Putting the strand silk for 3D printing obtained in the step (2) into a fused deposition modeling 3D printer, and preparing an electromagnetic shielding part with a porous structure by a fused deposition modeling 3D printing technology; the fused deposition modeling 3D printing technology comprises the following process parameters: and (3) according to a three-dimensional digital model slice of a required piezoelectric product, arranging extruded strands to print in a linear filling mode, stacking and accumulating layer by layer with an internal filling angle of 0 DEG/90 DEG, wherein the internal filling density is 45-60%, the diameter of a nozzle is 1.0 +/-0.01 mm, the temperature of a printing nozzle is consistent with the extrusion temperature in the step (2), the temperature of a hot bed is 50-60 ℃, and the printing speed is 250-350 mm/min.

2. The method of claim 1, further comprising: in the step (1), the polyolefin elastomer powder material comprises any one of Tao chemical polyolefin elastomers Engage 8003, engage 8400 and Engage 8450.

3. The method of claim 1, further comprising: the carbon-based filler for electromagnetic shielding in the step (1) is selected from any one or more of carbon nano tube, carbon black, graphite, graphene and carbon fiber.

4. The method of claim 1, further comprising: the powder surface coating treatment in the step (1) adopts a solution ultrasonic coating method, and specifically comprises the steps of carrying out ultrasonic treatment on polyolefin elastomer powder and carbon-based filler for electromagnetic shielding in an ethanol solution, stirring and dispersing, standing to coat the carbon-based filler for electromagnetic shielding on the surface of the powder of the polyolefin elastomer powder, filtering and drying to obtain composite powder coated with the carbon-based filler for electromagnetic shielding on the surface; wherein the technological parameters of the solution ultrasonic coating method are as follows: the ultrasonic power is 800W-1000W, and the ultrasonic time is 1.5-2 h; the stirring speed is 450-600 r/min.

5. The method of claim 1, further comprising: the step (1) of uniformly mixing the polyolefin elastomer powder with the carbon-based filler for electromagnetic shielding to uniformly disperse the carbon-based filler for electromagnetic shielding in the polyolefin elastomer powder comprises any one of a millform solid-phase mechanochemical reactor, a high-speed mixer and a ball mill.

6. The method according to claim 1, characterized by comprising the following steps in parts by weight:

the carbon-based filler for electromagnetic shielding is graphene;

(III) putting the strand silk for 3D printing obtained in the step (II) into a fused deposition modeling 3D printer, and preparing the electromagnetic shielding part with the porous structure by a fused deposition modeling 3D printing technology; the fused deposition modeling 3D printing technology comprises the following process parameters: and (3) according to a three-dimensional digital model slice of a required piezoelectric product, arranging extruded strands to print in a linear filling mode, stacking and accumulating layer by layer with an internal filling angle of 0 DEG/90 DEG, wherein the internal filling density is 45-55%, the diameter of a nozzle is 1.0 +/-0.01 mm, the temperature of a printing nozzle is consistent with the extrusion temperature in the step (2), the temperature of a hot bed is 50-60 ℃, and the printing speed is 250-350 mm/min.

7. The method of claim 6, further comprising: in the step (III), the internal filling density is 50-55%.

8. The electromagnetic shielding product with porous structure prepared by the method for 3D printing the electromagnetic shielding product with porous structure based on polyolefin elastomer according to claim 1.