Electromagnetic radiation-proof PVC co-extrusion foamed plate and preparation method thereof

Abstract

This invention relates to the field of plastic processing technology for building and decoration, and discloses an electromagnetic radiation-shielding PVC co-extruded foam board and its preparation method. The PVC co-extruded foam board includes a PVC layer and a PVC foam layer. The PVC layer includes the following raw materials: PVC resin, polymer brush-modified graphene with side chain thiol groups, thiol-modified phosphate flame-retardant plasticizer, acid absorber, accelerator, bamboo powder, light calcium carbonate, stabilizer, lubricant, and coupling agent. The PVC foam layer includes the following raw materials: PVC resin, polymer brush-modified graphene with side chain thiol groups, thiol-modified phosphate flame-retardant plasticizer, acid absorber, accelerator, bamboo powder, light calcium carbonate, stabilizer, lubricant, coupling agent, foaming agent, and foaming regulator. This invention grafts polymer brush-modified graphene with side chain thiol groups and thiol-modified phosphate flame-retardant plasticizer into PVC resin, and the prepared PVC co-extruded foam board has excellent electromagnetic shielding and good flame-retardant effect.

Description

Technical Field

[0001] This invention belongs to the field of processing technology of plastic materials for building and decoration, and relates to the preparation of PVC co-extruded foamed board, specifically to an electromagnetic radiation resistant PVC co-extruded foamed board and its preparation method. Background Technology

[0002] With the rapid development of electronic information technology, electromagnetic radiation in the environment is increasing exponentially. Electromagnetic radiation not only affects the normal operation of electronic devices, reducing their lifespan and performance, but also causes serious harm to human health. Therefore, equipping buildings with electromagnetic shielding functions is crucial for improving the home environment and enhancing the quality of life, thus avoiding the adverse effects of electromagnetic radiation.

[0003] Due to its lightweight, heat insulation, moisture resistance, flame retardancy, and ease of construction, PVC co-extruded foam board has been widely used in recent years as a substitute for natural wood in building exterior walls, interior decoration, and building partitions. However, existing PVC co-extruded foam boards have relatively limited functions and lack electromagnetic shielding capabilities, thus failing to provide protection against electromagnetic radiation. Summary of the Invention

[0004] To address the problems existing in the prior art, the present invention aims to provide an electromagnetic radiation shielding PVC co-extruded foam board and its preparation method. By grafting polymer-modified graphene with side chain thiol groups and thiol-modified phosphate flame-retardant plasticizer into PVC resin, the prepared PVC co-extruded foam board not only has high strength, but also has excellent electromagnetic shielding effect and good flame retardant effect.

[0005] This invention is achieved through the following technical solution:

[0006] An electromagnetic radiation shielding PVC co-extruded foam board includes a PVC layer and a PVC foam layer.

[0007] The PVC layer is composed of the following raw materials in parts by weight: 100 parts PVC resin, 10-15 parts modified graphene with side chain thiol groups, 3-8 parts thiol-modified phosphate flame retardant plasticizer, 3-6 parts acid absorbent, 1-5 parts accelerator, 15-25 parts bamboo powder, 40-50 parts light calcium carbonate, 5-7 parts stabilizer, 1-2 parts lubricant, and 1-2 parts coupling agent.

[0008] The PVC foam layer is composed of the following raw materials in parts by weight: 100 parts PVC resin, 10-15 parts modified graphene with side chain thiol groups, 3-8 parts thiol-modified phosphate flame retardant plasticizer, 3-6 parts acid absorbent, 1-5 parts accelerator, 15-25 parts bamboo powder, 40-50 parts light calcium carbonate, 5-7 parts stabilizer, 1-2 parts lubricant, 1-2 parts coupling agent, 1-2 parts foaming agent, and 8-12 parts foaming regulator.

[0009] A further improvement to the present invention is as follows:

[0010] The polymer-modified graphene with thiol-containing side chains was prepared by the following method:

[0011] One part of graphene oxide was ultrasonically dispersed in 50 parts of water, and 50-70 parts of NaOH and 40-60 parts of monochloroacetic acid were added. The mixture was ultrasonicated for 3-5 hours, centrifuged, and then vacuum dried at 60-80℃ to obtain carboxylated graphene.

[0012] One part of the above-mentioned carboxylated graphene was dispersed in 10 parts of thionyl chloride, and after purging with argon gas to remove oxygen, the reaction was carried out at 60~70℃ for 10~20h. After removing thionyl chloride under reduced pressure, acyl-chlorographene was obtained.

[0013] Add 1-2 parts of p-aminobenzyl bromide to a flask and place it in an ice-water bath. Disperse 1 part of the above-mentioned acyl-chlorographene in an appropriate amount of tetrahydrofuran solvent and slowly drop it into the flask. After reacting for 15-30 minutes, centrifuge and dry to obtain brominated graphene.

[0014] One part of phenyl magnesium bromide and 0.4-0.6 parts of carbon disulfide were added to a reaction vessel, and an appropriate amount of tetrahydrofuran solvent was added. After purging with argon gas to remove oxygen, the mixture was stirred at room temperature for 30-60 minutes. Then, 1-1.5 parts of the above-mentioned brominated graphene were added, and the mixture was stirred at room temperature for 1-2 hours. The solution was then washed sequentially with a mixture of ice water / ether at a mass ratio of 3:1 and water. The solvent was further removed under reduced pressure to obtain RAFT reagent modified graphene.

[0015] An olefinic vinyl monomer, azobisisobutyronitrile, and RAFT-modified graphene with a mass ratio of 100:0.5~1:1~2 were added to a reaction vessel. An appropriate amount of ethanol solvent was added, and after purging with argon gas to remove oxygen, the reaction was carried out at 60~80℃ for 2~4 hours. After centrifugation and drying, polymer brush-modified graphene with thiol-containing side chains was obtained.

[0016] Furthermore, the olefinic vinyl monomer is one or a mixture of several of allyl mercaptan, 2-methyl-2-propen-1-thiol and isopentenyl mercaptan.

[0017] Furthermore, the mercapto-modified phosphate flame-retardant plasticizer is prepared by the following method:

[0018] A phosphate ester flame-retardant plasticizer and a mercapto modifier with a molar ratio of 1:1.1~1.5 are dissolved in N,N'-dimethylformamide, and zinc powder with a mass fraction of 1~3% of the mercapto modifier is added. After reacting at 100~110℃ for 1~2 hours, the solution is poured into cold water to precipitate, filtered and dried to obtain the mercapto-modified phosphate ester flame-retardant plasticizer.

[0019] Furthermore, the phosphate ester flame-retardant plasticizer is one or a mixture of several of the following: diethylphosphoacetic acid, 3-(dimethylphosphono)propionic acid, 3-(diethoxyphospho)propionic acid, 4-(diethylphosphine)butyric acid, 2-(diethoxyphospho)butyric acid, and 5-(diethylphosphocarboxyl)valerate.

[0020] And / or, the thiol modifier is one or a mixture of several of 3-aminothiophenol, 4-aminothiophenol, and mercaptoethylamine.

[0021] Furthermore, the PVC resin is at least one of SG7 and SG8 types;

[0022] And / or, the acid absorbent is at least one of MgO and ZnO;

[0023] And / or, the promoter is at least one of bis(trimethylolpropane) and polyethylene glycol;

[0024] And / or, the stabilizer is one or a mixture of several of the following: organotin stabilizers, calcium-zinc composite stabilizers, and lead salt stabilizers;

[0025] And / or, the lubricant is one or a mixture of several of stearic acid, polyethylene wax, fatty alcohol dicarboxylic acid ester and oxidized polyethylene wax;

[0026] And / or, the coupling agent is one or a mixture of several of the following: titanate coupling agent, aluminate coupling agent, borate coupling agent and silane coupling agent;

[0027] And / or, the foaming agent is one or a mixture of several of sodium bicarbonate, azodicarbonamide and benzenesulfonyl hydrazine;

[0028] And / or, the foaming regulator is a copolymer of acrylates and methacrylates.

[0029] Furthermore, the bamboo powder has a particle size between 60 and 200 mesh;

[0030] And / or, the light calcium carbonate particle size is between 2500 and 5000 mesh.

[0031] A further improvement of the present invention is as follows:

[0032] The above-mentioned method for preparing electromagnetic radiation shielding PVC co-extruded foam board includes the following steps:

[0033] S1: Weigh the raw materials of the PVC layer and the PVC foam layer according to the weight ratio, and add them to the mixing device for stirring and mixing to obtain the PVC layer mixture and the PVC foam layer mixture.

[0034] S2: The PVC foam layer mixture is added to the main extruder and the PVC layer mixture is added to the auxiliary extruder. The mixture is then extruded from the outlets of the main and auxiliary extruders and enters the mold through the feed inlet of the mold via the distributor. After cooling and shaping, the PVC co-extruded foam board is obtained.

[0035] A further improvement to the present invention is as follows:

[0036] In S1, the mixing process of the PVC layer is as follows: First, PVC resin and stabilizer are added to a high-speed mixing device and stirred and heated at a low speed of 250~350 r / min; when the temperature rises to 70~80℃, the speed is increased to 1000~1200 r / min, and lubricant, polymer brush-modified graphene with side chain containing thiol groups, thiol-modified phosphate flame-retardant plasticizer, acid absorbent, and accelerator are added; when the temperature rises to 100~105℃, bamboo powder, light calcium carbonate, and coupling agent are added; when the temperature is stirred and heated to 115~120℃, the material in the high-speed mixing device is transferred to a low-speed mixing device; and the mixture is stirred and cooled to 40~50℃ at a speed of 80~100 r / min to obtain the PVC layer mixture.

[0037] And / or, the mixing process of the PVC foam layer specifically includes: first, adding PVC resin and stabilizer to a high-speed mixing device and stirring and heating at a low speed of 250~350 r / min; when the temperature rises to 70~80℃, increasing the speed to 1000~1200 r / min, and adding lubricant, foaming agent, foaming regulator, polymer brush-modified graphene with side chain thiol groups, thiol-modified phosphate flame-retardant plasticizer, acid absorbent, and accelerator; when the temperature rises to 100~105℃, adding bamboo powder, light calcium carbonate, and coupling agent; when stirring and heating to 115~120℃, transferring the material in the high-speed mixing device to a low-speed mixing device; stirring and cooling to 40~50℃ at a speed of 80~100 r / min to obtain the PVC foam layer mixture.

[0038] Furthermore, in S2, the specific temperatures of each zone of the main and auxiliary extruders are as follows: Zone 1 150~160℃, Zone 2 155~165℃, Zone 3 165~175℃, Zone 4 170~180℃, Die 165~175℃, and Die Lid 150~160℃.

[0039] The beneficial effects of this invention are as follows:

[0040] This invention grafts polymer molecular brushes containing thiol groups on the surface of graphene oxide via RAFT polymerization. The thiol groups from these polymer molecular brush side chains then react with PVC resin to graft graphene into the resin, improving its dispersibility and compatibility. This results in excellent electromagnetic shielding properties in the PVC co-extruded foam board. Simultaneously, a thiol-modified phosphate ester flame-retardant plasticizer is grafted into the PVC resin. This avoids the precipitation problem of traditional external plasticizers in the product. Furthermore, the phosphate ester decomposes upon heating to form phosphoric acid and polyphosphoric acid, which tightly bind with carbon residue, forming a dense, phosphorus-rich carbonized layer on the material surface. This prevents heat radiation from penetrating the material, resulting in excellent flame-retardant properties in the PVC co-extruded foam board. Detailed Implementation

[0041] The present invention will now be described in detail with reference to specific embodiments.

[0042] Example 1

[0043] Preparation of polymer brush-modified graphene with thiol-containing side chains:

[0044] 100g of graphene oxide was ultrasonically dispersed in 5L of water, 5kg of NaOH and 4kg of monochloroacetic acid were added, ultrasonicated for 3h, centrifuged and vacuum dried at 80℃ to obtain carboxylated graphene.

[0045] 100g of the above-mentioned carboxylated graphene was dispersed in 1L of thionyl chloride, and after purging with argon to remove oxygen, it was reacted at 70℃ for 10h. After removing thionyl chloride under reduced pressure, acyl-chlorographene was obtained.

[0046] Add 100g of p-aminobenzyl bromide to a flask and place it in an ice-water bath. Disperse 100g of acyl-chlorographene in 1L of tetrahydrofuran solvent and slowly drop it into the flask. After reacting for 20 minutes, centrifuge and dry to obtain brominated graphene.

[0047] 100g of phenyl magnesium bromide and 50g of carbon disulfide were added to a reaction vessel, 1L of tetrahydrofuran solvent was added, and after purging with argon gas to remove oxygen, the mixture was stirred at room temperature for 30min. Then, 100g of the above-mentioned brominated graphene was added, and the mixture was stirred at room temperature for 2h. The solution was washed successively with a mixture of ice water / ether at a mass ratio of 3:1 and water. After further removing the solvent under reduced pressure, RAFT reagent modified graphene was obtained.

[0048] 5 kg of allyl mercaptan, 25 g of azobisisobutyronitrile, and 50 g of RAFT reagent-modified graphene were added to a reaction vessel. 5 L of ethanol solvent was added, and after purging with argon gas to remove oxygen, the reaction was carried out at 60 °C for 3 h. After centrifugation and drying, polymer brush-modified graphene with thiol-containing side chains was obtained.

[0049] Preparation of mercapto-modified phosphate flame-retardant plasticizers:

[0050] 1.4 L of 3-(diethoxyphosphono)propionic acid and 1 kg of 4-aminobenzylthiophenol were dissolved in 2 L of N,N'-dimethylformamide, and 20 g of zinc powder was added. After reacting at 110 °C for 1 h, the solution was poured into cold water to precipitate, filtered and dried to obtain a mercapto-modified phosphate flame retardant plasticizer.

[0051] PVC layer preparation: Weigh out 100kg of SG7 type PVC resin, 10kg of polymer brush-modified graphene with side chain containing thiol groups, 3kg of thiol-modified phosphate flame retardant plasticizer, 3kg of MgO, 3kg of bis(trimethylolpropane), 5kg of calcium-zinc composite stabilizer, 1kg of polyethylene wax, 20kg of 150-mesh bamboo powder, 40kg of 2500-mesh light calcium carbonate, and 1kg of titanate coupling agent for later use;

[0052] PVC foam layer preparation: Weigh 100kg SG7 type PVC resin, 10kg side chain mercapto-containing polymer brush-modified graphene, 3kg mercapto-modified phosphate flame retardant plasticizer, 3kg MgO, 3kg bis(trimethylolpropane), 5kg calcium zinc composite stabilizer, 1kg polyethylene wax, 20kg 150 mesh bamboo powder, 40kg 2500 mesh light calcium carbonate, 1kg titanate coupling agent, 8kg acrylate and methacrylate multi-component copolymers, and 1kg azodicarbonamide for later use.

[0053] Preparation of electromagnetic radiation shielded PVC co-extruded foam board:

[0054] S1: PVC layer mixing and PVC foam layer mixing, wherein the PVC layer mixing process is as follows:

[0055] SG7 type PVC resin and calcium-zinc composite stabilizer are added to a high-speed mixing device and stirred and heated at a low speed of 300 r / min. When the temperature rises to 70℃, the speed is increased to 1000 r / min, and polymer-modified graphene with side chain thiol groups, thiol-modified phosphate flame retardant plasticizer, MgO, bis(trimethylolpropane) and polyethylene wax are added. When the temperature rises to 100℃, 150-mesh bamboo powder, 2500-mesh light calcium carbonate and titanate coupling agent are added. When the temperature rises to 120℃, the material in the high-speed mixing device is transferred to a low-speed mixing device. The mixture is stirred and cooled to 45℃ at a speed of 100 r / min to obtain the PVC layer mixture.

[0056] The specific mixing process for the PVC foam layer is as follows: SG7 type PVC resin and calcium-zinc composite stabilizer are added to a high-speed mixing device and stirred and heated at a low speed of 300 r / min; when the temperature rises to 70℃, the speed is increased to 1000 r / min, and polymer-modified graphene with side chain thiol groups, thiol-modified phosphate flame retardant plasticizer, MgO, bis(trimethylolpropane), polyethylene wax, azodicarbonamide, and acrylate and methacrylate multi-component copolymers are added; when the temperature rises to 100℃, 150-mesh bamboo powder, 2500-mesh light calcium carbonate, and titanate coupling agent are added; when the temperature rises to 120℃, the material in the high-speed mixing device is transferred to a low-speed mixing device; the mixture is stirred and cooled to 45℃ at a speed of 100 r / min to obtain the PVC foam layer mixture.

[0057] S2: The PVC foam layer mixture is added to the main extruder and the PVC layer mixture is added to the auxiliary extruder. The temperatures of each zone of the main and auxiliary extruders are as follows: Zone 1 160℃, Zone 2 165℃, Zone 3 175℃, Zone 4 180℃, Die 175℃, Die lip 160℃. The discharge ports of the main and auxiliary extruders are connected to the feed port of the die through a distributor. The materials extruded from the main and auxiliary extruders enter the die through the distributor and are cooled and shaped to obtain PVC co-extruded foamed board.

[0058] Example 2

[0059] In this embodiment, the amount of polymer-modified graphene with thiol-containing side chains added to both the PVC layer and the PVC foam layer is 12 kg. Apart from this, this embodiment is exactly the same as that in Embodiment 1, and will not be repeated here.

[0060] Example 3

[0061] In this embodiment, the amount of polymer-modified graphene with thiol-containing side chains added to both the PVC layer and the PVC foam layer is 15 kg. Apart from this, this embodiment is exactly the same as that in Embodiment 1, and will not be repeated here.

[0062] Example 4

[0063] In this embodiment, the amount of mercapto-modified phosphate flame retardant plasticizer added to both the PVC layer and the PVC foam layer is 5 kg. Apart from this, this embodiment is exactly the same as that in Embodiment 1, and will not be repeated here.

[0064] Example 5

[0065] In this embodiment, the amount of mercapto-modified phosphate flame retardant plasticizer added to both the PVC layer and the PVC foam layer is 8 kg. Apart from this, this embodiment is exactly the same as that in Embodiment 1, and will not be repeated here.

[0066] The physical properties of the electromagnetic radiation shielding PVC co-extruded foam boards prepared in Examples 1 to 5 were tested, and the test results are shown in Table 1.

[0067] Table 1. Physical property data of electromagnetic radiation shielding PVC co-extruded foam boards prepared in Examples 1 to 5

[0068] Example 1 Example 2 Example 3 Example 4 Example 5 Flexural modulus (GPa) 1.31 1.37 1.4 1.23 1.08 Shielding effectiveness (dB) 24 29 32 21 20 Fire resistance rating B1 B1 B1 B1 B1

[0069] Note: The electromagnetic shielding performance test range is 2~18GHz.

[0070] Table 1 shows that, within the scope defined by this invention, the PVC co-extruded foam board exhibits good flame retardancy, with a fire resistance rating of B1. Comparing embodiments 1-3, it can be seen that as the amount of polymer-modified graphene with side chain thiol groups increases, the flexural modulus and electromagnetic shielding effectiveness of the PVC foam board gradually increase. This is because graphene has high electrical conductivity and excellent mechanical properties, resulting in significant electromagnetic energy loss. Furthermore, the functional groups and defects contained in graphene oxide also increase the polarization loss of electromagnetic waves. When graphene interconnects with each other in the PVC matrix to form a continuous conductive network structure, both the mechanical and electromagnetic shielding properties of the co-extruded foam board are improved. Comparing embodiments 1, 4, and 5, Table 1 shows that, with the increase of the content of thiol-modified phosphate flame-retardant plasticizer, the flexural modulus of the PVC co-extruded foam board gradually decreases, and the shielding effectiveness slightly decreases. As the plasticizer content increases, the interaction forces between PVC molecular chains decrease, the resin becomes softer, and therefore the flexural modulus gradually decreases. The decrease in shielding effectiveness is mainly due to the increased plasticizer content, which leads to a lower proportion of thiol-modified graphene in the material. On the other hand, thiol-modified phosphate flame-retardant plasticizers also react with PVC resin, affecting the grafting amount of thiol-modified graphene onto the PVC resin, resulting in some graphene failing to bond well with the PVC matrix. When the amount of thiol-modified graphene added exceeds the range set in this invention, if the addition amount is too low, the distance between graphene nanosheets is large, resulting in low electrical conductivity and weak electromagnetic shielding ability of the PVC co-extruded foam board; if the addition amount is too high, exceeding the percolation threshold, the electromagnetic shielding performance of the PVC co-extruded foam board does not change significantly.

[0071] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent transformations or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A PVC co-extruded foam board for electromagnetic radiation protection, the PVC co-extruded foam board comprising a PVC layer and a PVC foam layer, characterized in that, The PVC layer is composed of the following raw materials in parts by weight: 100 parts PVC resin, 10-15 parts polymer-modified graphene with side chain containing thiol groups, 3-8 parts thiol-modified phosphate flame retardant plasticizer, 3-6 parts acid absorbent, 1-5 parts accelerator, 15-25 parts bamboo powder, 40-50 parts light calcium carbonate, 5-7 parts stabilizer, 1-2 parts lubricant, and 1-2 parts coupling agent. The PVC foam layer is composed of the following raw materials in parts by weight: 100 parts PVC resin, 10-15 parts modified graphene with side chain thiol groups, 3-8 parts thiol-modified phosphate flame retardant plasticizer, 3-6 parts acid absorbent, 1-5 parts accelerator, 15-25 parts bamboo powder, 40-50 parts light calcium carbonate, 5-7 parts stabilizer, 1-2 parts lubricant, 1-2 parts coupling agent, 1-2 parts foaming agent, and 8-12 parts foaming regulator. The polymer-modified graphene with thiol-containing side chains was prepared by the following method: One part of graphene oxide was ultrasonically dispersed in 50 parts of water, and 50-70 parts of NaOH and 40-60 parts of monochloroacetic acid were added. The mixture was ultrasonicated for 3-5 hours, centrifuged, and then vacuum dried at 60-80℃ to obtain carboxylated graphene. One part of the above-mentioned carboxylated graphene was dispersed in 10 parts of thionyl chloride, and after purging with argon gas to remove oxygen, the reaction was carried out at 60~70℃ for 10~20h. After removing thionyl chloride under reduced pressure, acyl-chlorographene was obtained. Add 1-2 parts of p-aminobenzyl bromide to a flask and place it in an ice-water bath. Disperse 1 part of the above-mentioned acyl-chlorographene in an appropriate amount of tetrahydrofuran solvent and slowly drop it into the flask. After reacting for 15-30 minutes, centrifuge and dry to obtain brominated graphene. One part of phenyl magnesium bromide and 0.4-0.6 parts of carbon disulfide were added to a reaction vessel, and an appropriate amount of tetrahydrofuran solvent was added. After purging with argon gas to remove oxygen, the mixture was stirred at room temperature for 30-60 minutes. Then, 1-1.5 parts of the above-mentioned brominated graphene were added, and the mixture was stirred at room temperature for 1-2 hours. The solution was then washed sequentially with a mixture of ice water / ether at a mass ratio of 3:1 and water. The solvent was further removed under reduced pressure to obtain RAFT reagent modified graphene. An olefin monomer, azobisisobutyronitrile, and RAFT-modified graphene in a mass ratio of 100:0.5~1:1~2 were added to a reaction vessel. An appropriate amount of ethanol solvent was added, and after purging with argon gas to remove oxygen, the reaction was carried out at 60~80℃ for 2~4 hours. After centrifugation and drying, polymer-modified graphene with mercapto-containing side chains was obtained. The olefin monomer was one or a mixture of several of allyl mercaptan, 2-methyl-2-propen-1-thiol, and isopentenyl mercaptan. The mercapto-modified phosphate flame-retardant plasticizer is prepared by the following method: A phosphate ester flame-retardant plasticizer and a mercapto modifier with a molar ratio of 1:1.1~1.5 are dissolved in N,N'-dimethylformamide, and zinc powder with a mass fraction of 1~3% of the mercapto modifier is added. After reacting at 100~110℃ for 1~2 hours, the solution is poured into cold water to precipitate, filtered, and dried to obtain the mercapto-modified phosphate ester flame-retardant plasticizer. The phosphate ester flame-retardant plasticizer is one or a mixture of several of diethylphosphoacetic acid, 3-(dimethylphosphono)propionic acid, 3-(diethoxyphospho)propionic acid, 4-(diethylphosphine)butyric acid, 2-(diethoxyphospho)butyric acid, and 5-(diethylphosphino)valerate. The mercapto modifier is one or a mixture of several of 3-aminobenzylthiophenol, 4-aminobenzylthiophenol, and mercaptoethylamine.

2. The electromagnetic radiation shielding PVC co-extruded foam board according to claim 1, characterized in that, The PVC resin is at least one of SG7 and SG8 types; And / or, the acid absorbent is at least one of MgO and ZnO; And / or, the promoter is at least one of bis(trimethylolpropane) and polyethylene glycol; And / or, the stabilizer is one or a mixture of several of the following: organotin stabilizers, calcium-zinc composite stabilizers, and lead salt stabilizers; And / or, the lubricant is one or a mixture of several of stearic acid, polyethylene wax, fatty alcohol dicarboxylic acid ester and oxidized polyethylene wax; And / or, the coupling agent is one or a mixture of several of the following: titanate coupling agent, aluminate coupling agent, borate coupling agent and silane coupling agent; And / or, the foaming agent is one or a mixture of several of sodium bicarbonate, azodicarbonamide and benzenesulfonyl hydrazine.

3. The electromagnetic radiation shielding PVC co-extruded foam board according to claim 1, characterized in that, The bamboo powder has a particle size between 60 and 200 mesh; And / or, the light calcium carbonate particle size is between 2500 and 5000 mesh.

4. A method for preparing an electromagnetic radiation-resistant PVC co-extruded foam board as described in any one of claims 1-3, characterized in that, Includes the following steps: S1: Weigh the raw materials of the PVC layer and the PVC foam layer according to the weight ratio, add them to the mixing device and stir to obtain the PVC layer mixture and the PVC foam layer mixture. S2: The PVC foam layer mixture is added to the main extruder and the PVC layer mixture is added to the auxiliary extruder. The mixture is then extruded from the outlets of the main and auxiliary extruders and enters the mold through the feed inlet of the mold via the distributor. After cooling and shaping, the PVC co-extruded foam board is obtained.

5. The method for preparing the electromagnetic radiation shielding PVC co-extruded foam board according to claim 4, characterized in that, In S1, the PVC layer mixing process is as follows: First, PVC resin and stabilizer are added to a high-speed mixing device and stirred and heated at a low speed of 250~350 r / min; when the temperature rises to 70~80℃, the speed is increased to 1000~1200 r / min, and lubricant, polymer brush-modified graphene with side chain containing thiol groups, thiol-modified phosphate flame-retardant plasticizer, acid absorbent, and accelerator are added; when the temperature rises to 100~105℃, bamboo powder, light calcium carbonate, and coupling agent are added; when the temperature is stirred and heated to 115~120℃, the material in the high-speed mixing device is transferred to a low-speed mixing device; and the mixture is stirred and cooled to 40~50℃ at a speed of 80~100 r / min to obtain the PVC layer mixture. And / or, the specific mixing process of the PVC foam layer is as follows: First, PVC resin and stabilizer are added to a high-speed mixing device and stirred and heated at a low speed of 250~350 r / min; when the temperature rises to 70~80℃, the speed is increased to 1000~1200 r / min, and lubricant, foaming agent, foaming regulator, polymer brush-modified graphene with side chain thiol groups, thiol-modified phosphate flame-retardant plasticizer, acid absorbent and accelerator are added; when the temperature rises to 100~105℃, bamboo powder, light calcium carbonate and coupling agent are added; when the temperature is stirred and heated to 115~120℃, the material in the high-speed mixing device is transferred to a low-speed mixing device; the mixture is stirred and cooled to 40~50℃ at a speed of 80~100 r / min to obtain the PVC foam layer mixture.

6. The method for preparing electromagnetic radiation shielding PVC co-extruded foam board according to claim 4, characterized in that, In S2, the specific temperatures of each zone of the main and auxiliary extruders are as follows: Zone 1 150~160℃, Zone 2 155~165℃, Zone 3 165~175℃, Zone 4 170~180℃, Die 165~175℃, and Die Lid 150~160℃.