A graphene conductive aluminum foil for drag chain flexible cables and its preparation process

Abstract

The present application relates to the technical field of flexible cable auxiliary material preparation, in particular to a graphene conductive aluminum foil for use in drag chain flexible cables and its preparation process. The graphene conductive aluminum foil includes a base shielding layer and a graphene reinforced shielding layer, the thickness of the graphene reinforced shielding layer is equal to 0.2-1.0 times the thickness of the base shielding layer; the base shielding layer is an aluminum foil or an aluminized flexible polymer resin film; the graphene reinforced shielding layer is prepared by curing a hydroxylated graphene-modified polyurethane resin; the hydroxylated graphene-modified polyurethane includes hydroxylated graphene and an NCO-terminated polyurethane resin. The drag chain flexible cable prepared from the graphene conductive aluminum foil provided in the present invention has a cyclic bending of ≥4 million times at a bending radius of 7x the cable diameter, meeting the demand for shielding materials for drag chain flexible cables for industrial robots.

Description

Technical Field

[0001] The present application relates to the technical field of flexible cable auxiliary material preparation, and in particular to a graphene conductive aluminum foil for drag chain flexible cables and a preparation process thereof. Background Art

[0002] Drag chain cables are highly flexible cables that can move back and forth with the drag chain and are resistant to wear and tear. They are widely used in drag chain systems, electronic information sensing technology, computer systems, measurement and control technology, industrial robotics, and other fields. The rapid development of industrial robots has placed higher demands on the electromagnetic interference resistance of drag chain cables. Good shielding materials ensure stable data transmission and protect the cables from electromagnetic interference and other influences.

[0003] At present, the traditional shielding material used in drag chain flexible cables is usually aluminum foil. The overall anti-electromagnetic interference performance is improved by controlling the number of aluminum foil layers in the drag chain flexible cables. However, the shielding layer formed by multiple layers of aluminum foil will affect the overall toughness and cycle life of the drag chain flexible cables.

[0004] To address the low toughness and cycle life issues of traditional shielding materials, researchers have developed a new type of graphene-conductive aluminum foil. A single layer of graphene-conductive aluminum foil can achieve the same anti-electromagnetic interference performance as a shielding layer composed of three layers of aluminum foil. Existing graphene-conductive aluminum foil comprises aluminum foil and a graphene-enhanced shielding layer adhered to the surface of the aluminum foil. The graphene-enhanced shielding layer is formed by curing a graphene slurry containing graphene, epoxy resin, a dispersant, and a leveling agent, with a graphene content of 10-30% by weight. Epoxy resin is the primary binder in the graphene slurry because it forms a strong bond with the aluminum foil, reducing the likelihood of the graphene-enhanced shielding layer detaching from the foil due to periodic bending.

[0005] Regarding the aforementioned existing graphene conductive aluminum foil, the inventors discovered that the graphene-enhanced shielding layer in the existing graphene conductive aluminum foil is relatively brittle. After 3 million bending cycles at a bending radius of 7x the cable diameter, delamination occurs between the graphene-enhanced shielding layer and the aluminum foil, significantly reducing the overall anti-electromagnetic interference performance. With the rapid development of industrial robots, higher requirements are being placed on the cyclic bending life of drag chain cables. At a bending radius of 7x the cable diameter, the cyclic bending life of the existing graphene conductive aluminum foil cannot meet this requirement. Therefore, the inventors provide a graphene conductive aluminum foil for use in flexible drag chain cables and a preparation process thereof. Summary of the Invention

[0006] In order to solve the problem that the existing graphene conductive aluminum foil has a low cyclic bending life and cannot meet the cyclic bending requirements of shielding materials for flexible cables of drag chains for industrial robots, the invention provides a graphene conductive aluminum foil for flexible cables of drag chains and a preparation process thereof. Under a bending radius of 7x the cable diameter, the cyclic bending life is ≥4 million times, which meets the requirements of shielding materials for flexible cables of drag chains for industrial robots.

[0007] The present application provides a graphene conductive aluminum foil for a drag chain flexible cable, which is realized by the following technical solutions:

[0008] A graphene conductive aluminum foil for a drag chain flexible cable is used in the drag chain flexible cable as a shielding material for the drag chain flexible cable. The graphene conductive aluminum foil includes a base shielding layer and a graphene reinforced shielding layer, and the thickness of the graphene reinforced shielding layer is equal to 0.2-1.0 times the thickness of the base shielding layer; the base shielding layer is aluminum foil or an aluminized flexible polymer resin film; the graphene reinforced shielding layer is prepared by curing a hydroxylated graphene-modified polyurethane resin; the hydroxylated graphene-modified polyurethane includes hydroxylated graphene and an NCO-terminated polyurethane resin; the hydroxylated graphene accounts for 10-25wt% of the total mass of the hydroxylated graphene-modified polyurethane; the NCO-terminated polyurethane resin has a hard segment content of 28-35wt%, an isocyanate index R value of 1.05-1.15, and a chain extension coefficient f value of 0.87-0.95.

[0009] The flexible cable for drag chains made of the graphene conductive aluminum foil provided in the present invention can be bent cyclically ≥4 million times at a bending radius of 7x the cable diameter, meeting the demand for shielding materials for flexible cables for drag chains used in industrial robots. In addition, the anti-electromagnetic interference performance of the graphene conductive aluminum foil is slightly better than that of existing graphene conductive aluminum foil.

[0010] Preferably, when the base shielding layer is aluminum foil with a thickness of 10-25 microns, surface acid etching treatment is required before coating the surface of the aluminum foil with the hydroxylated graphene-modified polyurethane resin. A groove structure is formed on the surface of the aluminum foil after acid etching, thereby increasing the contact area between the aluminum foil and the graphene-enhanced shielding layer and improving the bonding stability between the graphene-enhanced shielding layer and the base shielding layer.

[0011] Preferably, when the base shielding layer is aluminum foil with a thickness of 10-25 microns, before the hydroxylated graphene-modified polyurethane resin is coated on the surface of the aluminum foil, surface acid etching and low-temperature plasma treatment are required in sequence. The surface of the aluminum foil is acid-etched to form a groove structure, and then the surface of the aluminum foil is treated with low-temperature plasma to generate active functional groups. The groove structure formed on the surface of the aluminum foil increases the contact area between the aluminum foil and the graphene-enhanced shielding layer. The active functional groups on the surface of the aluminum foil are chemically bonded to the NCO-terminated polyurethane resin in the hydroxylated graphene-modified polyurethane, thereby improving the bonding stability between the graphene-enhanced shielding layer and the base shielding layer.

[0012] Preferably, the aluminum foil is made of 8-series aluminum alloy and surface-modified graphene, and the content of the surface-modified graphene is 0.25-2.0wt%; the surface-modified graphene includes graphene as a carrier and modified particles loaded on the surface of the graphene, and the modified particles are nano-scale aluminum metal clusters and / or single-atom aluminum; the modified particle loading rate in the surface-modified graphene is ≥4.0wt%.

[0013] By adopting the above technical solution, the aluminum foil contains surface-modified graphene, and inevitably, the surface-modified graphene is evenly distributed on the surface of the aluminum foil. The surface-modified graphene is activated to form active functional groups, and these active functional groups are chemically bonded to the NCO-terminated polyurethane resin in the hydroxylated graphene-modified polyurethane, which can further improve the bonding stability between the graphene-enhanced shielding layer and the substrate shielding layer.

[0014] Preferably, the aluminum foil is made of 8011 series aluminum alloy and surface-modified graphene, and the content of the surface-modified graphene is 0.8-1.2wt%; the surface-modified graphene includes graphene as a carrier and modified particles loaded on the surface of the graphene, and the modified particles are monatomic aluminum, which is anchored to defect points on the surface of the graphene; the loading rate of monatomic aluminum in the surface-modified graphene is 5.0wt%.

[0015] By adopting the above technical solution, the bonding stability between the graphene enhanced shielding layer and the base shielding layer can be further improved.

[0016] The present application provides a preparation process for graphene conductive aluminum foil for use in drag chain flexible cables, which is achieved through the following technical solutions:

[0017] A preparation process of graphene conductive aluminum foil for drag chain flexible cables comprises the following steps:

[0018] Step 1, preparation of hydroxylated graphene-modified polyurethane;

[0019] Step 2: The surface of the aluminum foil is subjected to surface modification treatment, which is acid etching treatment. The specific operation of the acid etching treatment is as follows: preparing a hydrochloric acid aqueous solution with a concentration of 0.1-0.5 mol / L, atomizing the hydrochloric acid aqueous solution with a concentration of 0.1-0.5 mol / L and spraying it on the surface of the aluminum foil, the amount of the atomized hydrochloric acid aqueous solution is 1-3 g / m2, and after acid etching for 300-360 seconds, rinsing with distilled water at least three times and drying;

[0020] Alternatively, the surface modification treatment further includes low-temperature plasma treatment, wherein the specific operation of the low-temperature plasma treatment is as follows: the aluminum foil that has been subjected to acid etching is placed in a low-temperature plasma treatment apparatus, the power is adjusted to 800-1000W, the gas pressure is adjusted to 0.20-0.25MPa, the working gas is nitrogen, and the treatment time is 200-400s. After the low-temperature plasma treatment is completed, the aluminum foil is rinsed with distilled water for at least three times and then dried.

[0021] Step 3: Apply the hydroxylated graphene-modified polyurethane prepared in step 1 to the surface of the aluminum foil that has been surface-modified in step 2, place it at 80-120° C. for 2-4 hours, and cool it to room temperature to obtain the graphene conductive aluminum foil for drag chain flexible cables.

[0022] The preparation process of the present invention is relatively simple, has low operation difficulty, and is easy to implement industrial production and manufacturing.

[0023] Preferably, when the base shielding layer is an aluminum-plated flexible polymer resin film, the aluminum-plated flexible polymer resin film includes an aluminum-plated film layer and a flexible polymer resin film, and the flexible polymer resin film is any one of TPU, TPEE, TPV, TPSiV, TPO, TPS, TPAE, PET, SEBS, and EVA; the thickness of the flexible polymer resin film is 50-200 microns; the thickness of the aluminum-plated film layer is 5-20 microns.

[0024] Preferably, the aluminized flexible polymer resin film is an aluminized TPU film with a Shore hardness of 80-90A, the TPU film thickness is 100±5 microns, and the aluminized film layer thickness is 15-20 microns.

[0025] Preferably, when the base shielding layer is an aluminum-plated flexible polymer resin film, the surface needs to be acid-etched before the hydroxylated graphene-modified polyurethane resin is coated on the aluminum-plated flexible polymer resin film. The surface of the aluminum-plated film forms a groove structure after acid etching. The thickness of the aluminum-plated film layer in the aluminum-plated flexible polymer resin film is 10-20 microns. The groove structure formed on the surface of the aluminum-plated film after acid etching increases the contact area between the aluminum-plated flexible polymer resin film and the graphene enhanced shielding layer, thereby improving the bonding stability between the graphene enhanced shielding layer and the base shielding layer.

[0026] The present application provides a preparation process for graphene conductive aluminum foil for use in drag chain flexible cables, which is achieved through the following technical solutions:

[0027] A preparation process of graphene conductive aluminum foil for drag chain flexible cables comprises the following steps:

[0028] Step 1, preparation of hydroxylated graphene-modified polyurethane;

[0029] Step 2: The surface of the aluminum-coated flexible polymer resin film is subjected to surface modification treatment, wherein the surface modification treatment is an acid etching treatment, and the specific operation of the acid etching treatment is as follows: preparing a hydrochloric acid aqueous solution with a concentration of 0.1-0.5 mol / L, atomizing the hydrochloric acid aqueous solution with a concentration of 0.1-0.5 mol / L and spraying it on the surface of the aluminum-coated flexible polymer resin film, wherein the amount of the atomized hydrochloric acid aqueous solution is 1-3 g / m2, and after the acid etching treatment for 300-360 seconds, rinsing with distilled water at least three times and drying;

[0030] Step three, apply the hydroxylated graphene-modified polyurethane prepared in step one on the surface of the aluminum-coated flexible polymer resin film that has completed the surface modification treatment in step two, place it at 65-95°C for 4-8 hours, and cool it to room temperature to obtain the graphene conductive aluminum foil for drag chain flexible cables.

[0031] The preparation process of the present invention is relatively simple, with low operating difficulty, and is easy to realize industrial production and manufacturing. The flexible cable of the drag chain prepared by using the above-mentioned graphene conductive aluminum foil has better bending resistance and cycle service life while ensuring anti-electromagnetic interference performance, and better meets the demand for shielding materials of flexible cables of drag chains for industrial robots.

[0032] In summary, this application has the following advantages:

[0033] 1. The graphene conductive aluminum foil provided in the present invention has good anti-electromagnetic interference performance. The flexible cable of the drag chain prepared with it can be bent cyclically ≥4 million times at a bending radius of 7x the cable diameter, meeting the demand for shielding materials for flexible cables of drag chains for industrial robots.

[0034] 2. In the present invention, the surface of the base shielding layer is modified to improve the bonding strength and bonding stability between the base shielding layer and the graphene enhanced shielding layer. The flexible cable of the drag chain prepared by the graphene conductive aluminum foil in the invention has better bending resistance and cycle service life while ensuring anti-electromagnetic interference performance.

[0035] 3. The preparation process of the present invention is relatively simple, has low operation difficulty, and is easy to implement industrial production. DETAILED DESCRIPTION

[0036] In order to further understand the present invention, preferred embodiments of the present invention are described below with reference to examples and comparative examples.

[0037] Example

[0038] A graphene conductive aluminum foil for a drag chain flexible cable comprises a base shielding layer and a graphene reinforced shielding layer. The thickness of the graphene reinforced shielding layer is 0.2-1.0 times the thickness of the base shielding layer.

[0039] Preferably, the thickness of the graphene enhanced shielding layer is equal to 0.4-0.6 times the thickness of the substrate shielding layer.

[0040] The base shielding layer is aluminum foil or aluminum-plated flexible polymer resin film.

[0041] When the base shielding layer is aluminum foil, the thickness of the aluminum foil is 10-25 microns. Preferably, when the base shielding layer is aluminum foil, the thickness of the aluminum foil is 20-25 microns.

[0042] When the base shielding layer is an aluminized flexible polymer resin film with a thickness of 50-200 microns, the aluminized flexible polymer resin film includes an aluminized film layer and a flexible polymer resin film, and the flexible polymer resin film is any one of TPU, TPEE, TPV, TPSiV, TPO, TPS, TPAE, PET, SEBS, and EVA. The thickness of the aluminized film layer is 5-20 microns.

[0043] Preferably, the aluminized flexible polymer resin film is an aluminized TPU film with a Shore hardness of 80-90 A. The TPU film has a thickness of 100±5 microns, and the aluminized film layer has a thickness of 15-20 microns.

[0044] The graphene-enhanced shielding layer is prepared by curing hydroxylated graphene-modified polyurethane resin.

[0045] The hydroxylated graphene-modified polyurethane is prepared from hydroxylated graphene and NCO-terminated polyurethane resin.

[0046] The hydroxylated graphene accounts for 10-25 wt % of the total mass of the hydroxylated graphene-modified polyurethane. Preferably, the hydroxylated graphene accounts for 22-26 wt % of the total mass of the hydroxylated graphene-modified polyurethane.

[0047] The hard segment content of the NCO-terminated polyurethane resin is 28-35wt%, the isocyanate index R value is 1.05-1.15, and the chain extension coefficient f value is 0.87-0.95.

[0048] Preferably, the hard segment content in the NCO-terminated polyurethane resin is 30-32 wt %, the isocyanate index R value is 1.08-1.10, and the chain extension coefficient f value*isocyanate index R value=1.

[0049] NCO-terminated polyurethane resins can be custom-made or existing NCO-terminated polyurethane resins can be used.

[0050] When the base shielding layer is aluminum foil with a thickness of 10-25 microns, surface acid etching treatment is required before coating the surface of the aluminum foil with the hydroxylated graphene-modified polyurethane resin. A groove structure is formed on the surface of the aluminum foil after acid etching, thereby increasing the contact area between the aluminum foil and the graphene-enhanced shielding layer and improving the bonding stability between the graphene-enhanced shielding layer and the base shielding layer.

[0051] Furthermore, before the hydroxylated graphene-modified polyurethane resin is coated on the surface of the aluminum foil, it is necessary to perform surface acid etching and low-temperature plasma treatment in sequence. The surface of the aluminum foil is subjected to acid etching to form a gully structure. The surface of the aluminum foil is then subjected to low-temperature plasma treatment to generate active functional groups. The working gas in the low-temperature plasma treatment is at least one of nitrogen, ammonia, oxygen, ozone, and air. The gully structure formed on the surface of the aluminum foil increases the contact area between the aluminum foil and the graphene-enhanced shielding layer. The active functional groups on the surface of the aluminum foil are chemically bonded to the NCO-terminated polyurethane resin in the hydroxylated graphene-modified polyurethane, thereby improving the bonding stability between the graphene-enhanced shielding layer and the substrate shielding layer.

[0052] To further improve the bonding stability between the base shielding layer and the graphene-enhanced shielding layer, the inventors developed a special aluminum foil. Specifically, the aluminum foil comprises an 8-series aluminum alloy and surface-modified graphene. Preferably, the 8-series aluminum alloy is an 8011-series aluminum alloy, which is commercially available. The surface-modified graphene content is 0.25-2.0 wt%, preferably 0.8-1.2 wt%.

[0053] Surface-modified graphene includes graphene as a carrier and modified particles loaded onto the graphene surface. The modified particles are nanoscale aluminum metal clusters and / or single-atom aluminum atoms. The modified particle loading in the surface-modified graphene is ≥4.0wt%. Both nano-aluminum cluster surface-modified graphene and single-atom aluminum surface-modified graphene can be custom-made. Preferably, the modified particles are single-atom aluminum atoms, which are anchored to defect sites on the graphene surface. The surface-modified graphene has a single-atom aluminum loading of 5.0wt%, custom-made at the Beijing Graphene Technology Institute.

[0054] Based on the base shielding layer being aluminum foil, a preparation process of graphene conductive aluminum foil for drag chain flexible cables includes the following steps:

[0055] Step 1, preparation of hydroxylated graphene-modified polyurethane;

[0056] Step 2: The surface of the aluminum foil is subjected to surface modification treatment, which is acid etching treatment. The specific operation of the acid etching treatment is as follows: prepare a hydrochloric acid aqueous solution with a concentration of 0.1-0.5 mol / L, atomize the hydrochloric acid aqueous solution with a concentration of 0.1-0.5 mol / L and spray it on the surface of the aluminum foil. The amount of the atomized hydrochloric acid aqueous solution is 1-3 g / m2. After the acid etching treatment for 300-360 seconds, rinse with distilled water for at least three times and dry it.

[0057] Alternatively, the surface modification treatment may also include low-temperature plasma treatment. The specific operation of the low-temperature plasma treatment is as follows: the aluminum foil that has been acid-etched is placed in a low-temperature plasma treatment apparatus, the power is adjusted to 800-1000W, the gas pressure is adjusted to 0.20-0.25MPa, the working gas is nitrogen, and the treatment time is 200-400s. After the low-temperature plasma treatment is completed, it is rinsed with distilled water for at least three times and then dried.

[0058] Step 3: Apply the hydroxylated graphene-modified polyurethane prepared in step 1 to the surface of the aluminum foil that has been surface-modified in step 2, place it at 80-120° C. for 2-4 hours, and cool it to room temperature to obtain the graphene conductive aluminum foil for drag chain flexible cables.

[0059] When the base shielding layer is an aluminum-coated flexible polymer resin film, a preparation process for graphene conductive aluminum foil for a drag chain flexible cable includes the following steps:

[0060] Step 1, preparation of hydroxylated graphene-modified polyurethane;

[0061] Step 2: The surface of the aluminum-coated flexible polymer resin film is subjected to surface modification treatment, which is acid etching treatment. The specific operation of the acid etching treatment is as follows: preparing a hydrochloric acid aqueous solution with a concentration of 0.1-0.5 mol / L, atomizing the hydrochloric acid aqueous solution with a concentration of 0.1-0.5 mol / L and spraying it on the surface of the aluminum-coated flexible polymer resin film, the amount of the atomized hydrochloric acid aqueous solution is 1-3 g / m2, and after acid etching for 300-360 seconds, rinse with distilled water at least three times and dry it;

[0062] Step three, apply the hydroxylated graphene-modified polyurethane prepared in step one on the surface of the aluminum-coated flexible polymer resin film that has completed the surface modification treatment in step two, place it at 65-95°C for 4-8 hours, and cool it to room temperature to obtain the graphene conductive aluminum foil for drag chain flexible cables.

[0063] When the base shielding layer is an aluminum-coated flexible polymer resin film, the prepared graphene conductive aluminum foil has excellent low-temperature flexibility. The flexible cable of the drag chain prepared with the graphene conductive aluminum foil has better bending resistance and cycle service life while ensuring anti-electromagnetic interference performance, and better meets the demand for shielding materials of flexible cables of drag chains for industrial robots.

[0064] The core creativity of the technical solution of the present invention is highlighted and demonstrated through the following examples and comparative examples.

[0065] Example 1: A graphene-conductive aluminum foil for use in drag chain flexible cables comprises a 15-micron-thick aluminum foil and a 10-micron-thick graphene-reinforced shielding layer. The graphene-reinforced shielding layer is prepared by curing a hydroxylated graphene-modified polyurethane resin. The hydroxylated graphene-modified polyurethane comprises hydroxylated graphene and an NCO-terminated polyurethane resin. The hydroxylated graphene accounts for 15 wt% of the total mass of the hydroxylated graphene-modified polyurethane. The NCO-terminated polyurethane resin has a hard segment content of 30.3 wt%, an isocyanate index (R) of 1.08, and a chain extension coefficient (f) of 1 / 1.08.

[0066] A preparation process of graphene conductive aluminum foil for drag chain flexible cables comprises the following steps:

[0067] Step 1, preparation of hydroxylated graphene-modified polyurethane:

[0068] S1.1. Heat 40 g of polytetrahydrofuran diol (PTMEG) (BASF PolyTHF 2000) and 74 g of polycaprolactone hexamethylene carbonate diol (CD2220PL, Daicel Corporation, Japan) to 120°C, vacuum dehydrate for 1 h, and set aside.

[0069] S1.2. Mix 40 g of polytetramethylene glycol (PTMEG) and 74 g of polycaprolactone hexamethylene carbonate (CD2220PL) that have undergone vacuum dehydration in S1.1, 15 g of MDI-50, 12.6 g of 4,4'-dicyclohexylmethane diisocyanate (HMDI), and 0.08 g of dibutyltin dilaurate as a catalyst, and heat to 85°C for prepolymerization for 3 h. Add acetone dropwise to adjust the viscosity to 2500 mPa·s to obtain a polyurethane prepolymer solution.

[0070] S1.3. Add 5.08 g of 3-methyl-1,5-pentanediol, 0.04 g of dibutyltin dilaurate (catalyst), 2 g of Efka SI 2741 (silicone defoamer), 3 g of DOWSIL 8526 (leveling agent), 1.6 g of antioxidant 1010, and 1.4 g of UV324 to the polyurethane prepolymer solution. Stir and mix at 240 rpm for 5 min. Heat to 95°C and react for 1 h. Add acetone dropwise to adjust the viscosity to 2500 mPa·s to obtain an NCO-terminated polyurethane resin.

[0071] S1.4. Adjust the temperature of the NCO-terminated polyurethane resin to 45°C. First, dry-knead 30g of hydroxylated graphene (TNRGOH hydroxylated graphene from Chengdu Organic Chemistry Co., Ltd., Chinese Academy of Sciences, purity >98wt%, thickness 0.55-3.74nm, diameter 0.5-3μm, number of layers <10, oxygen content >10wt%) and 3g of KH570 coupling agent for 5min. The resulting mixture was added to the NCO-terminated polyurethane resin and stirred at 160rpm for 5min. Then, acetone solvent was added dropwise to adjust the viscosity to 2500mPa·s, to obtain a hydroxylated graphene-modified polyurethane with a solid content of 42.5%.

[0072] Step 2: The surface of aluminum foil (15 μm thick, Jiangsu Keyao Aluminum Co., Ltd.) was subjected to surface modification treatment. The surface modification treatment was acid etching treatment. The specific operation of the acid etching treatment was as follows: a 0.2 mol / L hydrochloric acid aqueous solution was prepared, and the 0.2 mol / L hydrochloric acid aqueous solution was atomized and sprayed on the surface of the aluminum foil. The amount of the atomized hydrochloric acid aqueous solution was 2.0 g / m 2 After acid etching for 300s, rinse with distilled water three times and dry;

[0073] Step 3: Apply the hydroxylated graphene modified polyurethane prepared in step 1 to the surface of the aluminum foil that has been acid-etched and modified in step 2. The amount of hydroxylated graphene modified polyurethane applied is 1.2 g / dm 2 , place it at 120℃ to remove the organic solvent, then transfer it to an oven and maintain it at 95℃ for aging for 3 hours. Unpack and cool it to room temperature to obtain graphene conductive aluminum foil for drag chain flexible cables.

[0074] The difference between Example 2 and Example 1 is that the hydroxylated graphene accounts for 10 wt % of the total mass of the hydroxylated graphene-modified polyurethane.

[0075] The preparation methods of hydroxylated graphene-modified polyurethane are as follows: S1.4, adjust the temperature of the NCO-terminated polyurethane resin to 45°C, first dry-knead 18.9 g of hydroxylated graphene and 3 g of KH570 coupling agent for 5 minutes, add the resulting mixture to the NCO-terminated polyurethane resin, stir at 160 rpm for 5 minutes, and then add acetone solvent dropwise to adjust the viscosity to 2500 mPa·s.

[0076] The difference between Example 3 and Example 1 is that the hydroxylated graphene accounts for 20 wt % of the total mass of the hydroxylated graphene-modified polyurethane.

[0077] The preparation methods of hydroxylated graphene-modified polyurethane are as follows: S1.4, adjust the temperature of the NCO-terminated polyurethane resin to 45°C, first dry-knead 42.6 g of hydroxylated graphene and 3 g of KH570 coupling agent for 5 minutes, add the resulting mixture to the NCO-terminated polyurethane resin, stir at 160 rpm for 5 minutes, and then add acetone solvent dropwise to adjust the viscosity to 2500 mPa·s.

[0078] The difference between Example 4 and Example 1 is that the hydroxylated graphene accounts for 25 wt % of the total mass of the hydroxylated graphene-modified polyurethane.

[0079] The preparation methods of hydroxylated graphene-modified polyurethane are as follows: S1.4, adjust the temperature of the NCO-terminated polyurethane resin to 45°C, first dry-knead 56.8 g of hydroxylated graphene and 3 g of KH570 coupling agent for 5 minutes, add the resulting mixture to the NCO-terminated polyurethane resin, stir at 160 rpm for 5 minutes, and then add acetone solvent dropwise to adjust the viscosity to 2500 mPa·s.

[0080] The difference between Example 5 and Example 1 is that: in step 2, the surface of the aluminum foil is subjected to surface modification treatment, and the surface modification treatment is acid etching treatment. The specific operation of the acid etching treatment is as follows: a hydrochloric acid aqueous solution with a concentration of 0.1 mol / L is prepared, and the hydrochloric acid aqueous solution with a concentration of 0.1 mol / L is atomized and sprayed on the surface of the aluminum foil. The amount of the atomized hydrochloric acid aqueous solution is 2.0 g / m 2 After the acid etching for 300s, the product was rinsed three times with distilled water and dried. The other steps were the same as those in Example 1.

[0081] The difference between Example 6 and Example 1 is that: in step 2, the surface of the aluminum foil is subjected to surface modification treatment, and the surface modification treatment is acid etching treatment. The specific operation of the acid etching treatment is as follows: a hydrochloric acid aqueous solution with a concentration of 0.3 mol / L is prepared, and the hydrochloric acid aqueous solution with a concentration of 0.3 mol / L is atomized and sprayed on the surface of the aluminum foil. The amount of the atomized hydrochloric acid aqueous solution is 2.0 g / m 2 After acid etching for 300s, rinse with distilled water three times and dry.

[0082] The difference between Example 7 and Example 1 is that: in step 2, the surface of the aluminum foil is subjected to surface modification treatment, and the surface modification treatment is acid etching treatment. The specific operation of the acid etching treatment is as follows: a hydrochloric acid aqueous solution with a concentration of 0.4 mol / L is prepared, and the hydrochloric acid aqueous solution with a concentration of 0.4 mol / L is atomized and sprayed on the surface of the aluminum foil. The amount of the atomized hydrochloric acid aqueous solution is 2.0 g / m 2 After the acid etching for 300s, the product was rinsed three times with distilled water and dried. The other steps were the same as those in Example 1.

[0083] The difference between Example 8 and Example 1 is that: in step 2, the surface of the aluminum foil is subjected to surface modification treatment, and the surface modification treatment is acid etching treatment. The specific operation of the acid etching treatment is as follows: a hydrochloric acid aqueous solution with a concentration of 0.5 mol / L is prepared, and the hydrochloric acid aqueous solution with a concentration of 0.5 mol / L is atomized and sprayed on the surface of the aluminum foil. The amount of the atomized hydrochloric acid aqueous solution is 2.0 g / m 2 After the acid etching for 300s, the product was rinsed three times with distilled water and dried. The other steps were the same as those in Example 1.

[0084] The difference between Example 9 and Example 1 is that: in step 2, the surface of the aluminum foil is subjected to surface modification treatment, and the surface modification treatment is acid etching treatment. The specific operation of the acid etching treatment is as follows: a hydrochloric acid aqueous solution with a concentration of 0.15 mol / L is prepared, and the hydrochloric acid aqueous solution with a concentration of 0.15 mol / L is atomized and sprayed on the surface of the aluminum foil. The amount of the atomized hydrochloric acid aqueous solution is 2.0 g / m 2 After acid etching for 300s, rinse with distilled water three times, dry, and then spray with a 0.15mol / L hydrochloric acid aqueous solution on the surface of the aluminum foil. The amount of atomized hydrochloric acid aqueous solution is 2.0g / m 2 After the acid etching for 300s, the product was rinsed three times with distilled water and dried. The other steps were the same as those in Example 1.

[0085] The difference between Example 10 and Example 9 is that: in step 2, the surface of the aluminum foil is subjected to surface modification treatment, and the surface modification treatment is acid etching treatment. The specific operation of the acid etching treatment is as follows: a hydrochloric acid aqueous solution with a concentration of 0.15 mol / L is prepared, and the hydrochloric acid aqueous solution with a concentration of 0.15 mol / L is atomized and sprayed on the surface of the aluminum foil. The amount of the atomized hydrochloric acid aqueous solution is 2.0 g / m 2 After acid etching for 300s, rinse with distilled water three times, dry, and then spray with a 0.15mol / L hydrochloric acid aqueous solution on the surface of the aluminum foil. The amount of atomized hydrochloric acid aqueous solution is 2.0g / m 2 After acid etching for 300 seconds, the foil was rinsed three times with distilled water and dried. The resulting aluminum foil was then subjected to low-temperature plasma treatment. The specific operation of the low-temperature plasma treatment was as follows: the aluminum foil that had undergone the acid etching treatment was placed in a low-temperature plasma treatment apparatus with a power of 800 W and a gas pressure of 0.20 MPa. The working gas was nitrogen and the treatment time was 300 seconds. After the low-temperature plasma treatment, the foil was rinsed three times with distilled water and dried. The other steps were the same as those in Example 9.

[0086] Example 11 differs from Example 1 in that the aluminum foil is made of 8011 aluminum alloy and surface-modified graphene, with the surface-modified graphene content being 1.0 wt %. The aluminum foil is produced by Jiangsu Keyao Aluminum Co., Ltd. and has a thickness of 15 μm and a width of 45 cm.

[0087] The surface-modified graphene consists of graphene as a carrier and modified particles loaded onto the graphene surface. The modified particles are monatomic aluminum atoms, which are anchored to surface defects on the graphene. The loading ratio of the monatomic aluminum in the surface-modified graphene is 5.0 wt%. The surface-modified graphene was custom-made at the Beijing Graphene Technology Research Institute.

[0088] The preparation method disclosed by the Beijing Graphene Technology Research Institute is as follows: 200 mg of hydroxylated graphene is weighed and dispersed in 200 mL of deionized water to obtain a graphene dispersion; 1.2 g of KOH is weighed and dissolved in 200 mL of deionized water to obtain a KOH solution; the KOH solution is added dropwise to the graphene dispersion, stirred and dried at 80°C to obtain a graphene / KOH dry powder; 1 g of AlCl3 is weighed and placed in a crucible, and 1.4 g of graphene / KOH dry powder is placed in the crucible; the crucible containing AlCl3 and the crucible containing graphene / KOH dry powder are placed in the upstream and downstream areas of a tube furnace, respectively, and the tube furnace is sealed; Ar gas is introduced into the tube furnace, and Under Ar atmosphere, the upstream temperature zone of the tube furnace was heated from room temperature to 450°C at a heating rate of 10°C / min and kept warm for 1 hour. At the same time, the downstream temperature zone of the tube furnace was heated to 630°C at a heating rate of 14°C / min and kept warm for 1 hour to obtain a metal single atom-doped graphene precursor; the obtained metal single atom-doped graphene precursor was added to 100 ml of 1 mol / L dilute hydrochloric acid, stirred, vacuum filtered, washed, and dried to obtain surface-modified graphene.

[0089] The difference between Example 12 and Example 10 is that the aluminum foil is replaced by the aluminum foil in Example 11, which is made of 8011 series aluminum alloy and surface-modified graphene, and the content of the surface-modified graphene is 1.0 wt%.

[0090] Example 13 differs from Example 1 in that the base shielding layer is an aluminized TPU film. The aluminized TPU film has a Shore hardness of 85A (made from BASF's Elastollan 1185A10), a TPU film thickness of 100 microns, and an aluminized film layer (PVDF) thickness of 20 microns, custom-made by Hebei Weisai New Materials Technology Co., Ltd.

[0091] A preparation process of graphene conductive aluminum foil for drag chain flexible cables comprises the following steps:

[0092] Step 1: The preparation method of hydroxylated graphene-modified polyurethane is the same as the preparation method of hydroxylated graphene-modified polyurethane in Example 1;

[0093] Step 2: The surface of the aluminum-plated TPU film is modified by acid etching. The specific operation of the acid etching is as follows: prepare a 0.15 mol / L hydrochloric acid aqueous solution, atomize the 0.15 mol / L hydrochloric acid aqueous solution and spray it on the surface of the aluminum foil. The amount of the atomized hydrochloric acid aqueous solution is 1.5 g / m 2 After acid etching for 300s, rinse with distilled water three times and dry;

[0094] Step 3: Apply the hydroxylated graphene modified polyurethane prepared in step 1 to the surface of the aluminum foil that has been acid-etched and modified in step 2. The amount of hydroxylated graphene modified polyurethane applied is 1.2 g / dm 2 , place it at 75°C to remove the organic solvent for 3 hours, then transfer it to an oven and maintain it at 85°C for aging for 3 hours. Unpack and cool it to room temperature to obtain graphene conductive aluminum foil for drag chain flexible cables.

[0095] The difference between Example 14 and Example 13 is that: in step 2, the surface of the aluminum-plated TPU film is subjected to surface modification treatment, and the surface modification treatment is acid etching treatment. The specific operation of the acid etching treatment is as follows: a hydrochloric acid aqueous solution with a concentration of 0.15 mol / L is prepared, and the hydrochloric acid aqueous solution with a concentration of 0.15 mol / L is atomized and sprayed on the surface of the aluminum foil. The amount of the atomized hydrochloric acid aqueous solution is 1.5 g / m 2 After acid etching for 300s, rinse with distilled water three times, dry, and then spray with a 0.15mol / L hydrochloric acid aqueous solution on the surface of the aluminum foil. The amount of atomized hydrochloric acid aqueous solution is 2.0g / m 2 After acid etching for 300s, the product was rinsed three times with distilled water and dried. The other steps were the same as those in Example 13.

[0096] The difference between Comparative Example 1 and Example 1 is that the hydroxylated graphene-modified polyurethane is replaced by a graphene-modified epoxy resin, and the graphene content in the graphene-modified epoxy resin is 15 wt %.

[0097] Specifically, the formula of the graphene-modified epoxy resin is as follows: 60g epoxy resin E20, 15g maleic anhydride MA, 5g dicyandiamide, 1g KH570 coupling agent, 15g graphene, 1g antioxidant 1010, 2g defoaming agent BYK-A530, and 1g UV-531.

[0098] The difference between Comparative Example 2 and Example 1 is that the hydroxylated graphene accounts for 8 wt % of the total mass of the hydroxylated graphene-modified polyurethane.

[0099] The preparation method of hydroxylated graphene-modified polyurethane is as follows: S1.4, adjust the temperature of the NCO-terminated polyurethane resin to 45°C, dry-knead 14.8 g of hydroxylated graphene and 3 g of KH570 coupling agent for 5 minutes, add the resulting mixture to the NCO-terminated polyurethane resin, stir at 160 rpm for 5 minutes, and then add acetone solvent dropwise to adjust the viscosity to 2500 mPa·s. The remaining steps are the same as those in Example 1.

[0100] The difference between Comparative Example 3 and Example 1 is that the hydroxylated graphene accounts for 28 wt % of the total mass of the hydroxylated graphene-modified polyurethane.

[0101] The preparation method of hydroxylated graphene-modified polyurethane is as follows: S1.4, adjust the temperature of the NCO-terminated polyurethane resin to 45°C, dry-knead 66.3 g of hydroxylated graphene and 3 g of KH570 coupling agent for 5 minutes, add the resulting mixture to the NCO-terminated polyurethane resin, stir at 160 rpm for 5 minutes, and then add acetone solvent dropwise to adjust the viscosity to 2500 mPa·s. The remaining steps are the same as those in Example 1.

[0102] The difference between Comparative Example 4 and Example 1 is that: in step 2, the surface of the aluminum foil is subjected to surface modification treatment, and the surface modification treatment is acid etching treatment. The specific operation of the acid etching treatment is as follows: a hydrochloric acid aqueous solution with a concentration of 0.05 mol / L is prepared, and the hydrochloric acid aqueous solution with a concentration of 0.05 mol / L is atomized and sprayed on the surface of the aluminum foil. The amount of the atomized hydrochloric acid aqueous solution is 2.0 g / m 2 After the acid etching for 300s, the product was rinsed three times with distilled water and dried. The other steps were the same as those in Example 1.

[0103] The difference between Comparative Example 5 and Example 1 is that: in step 2, the surface of the aluminum foil is subjected to surface modification treatment, and the surface modification treatment is acid etching treatment. The specific operation of the acid etching treatment is as follows: a hydrochloric acid aqueous solution with a concentration of 0.65 mol / L is prepared, and the hydrochloric acid aqueous solution with a concentration of 0.65 mol / L is atomized and sprayed on the surface of the aluminum foil. The amount of the atomized hydrochloric acid aqueous solution is 2.0 g / m 2 After the acid etching for 300s, the product was rinsed three times with distilled water and dried. The other steps were the same as those in Example 1.

[0104] The difference between Comparative Example 6 and Example 1 is that: in step 2, the surface of the aluminum foil is not subjected to surface modification treatment, and is simply rinsed three times with distilled water and dried. The other steps are the same as those of Example 1.

[0105] The difference between Comparative Example 7 and Example 13 is that in step 2, the aluminum-coated TPU film is not subjected to surface modification treatment, but is rinsed three times with distilled water and dried. The other steps are the same as those in Example 1.

[0106] The difference between Comparative Example 8 and Example 13 is that: in step 2, the surface of the aluminum-plated TPU film is subjected to surface modification treatment, and the surface modification treatment is acid etching treatment. The specific operation of the acid etching treatment is as follows: a hydrochloric acid aqueous solution with a concentration of 0.02 mol / L is prepared, and the hydrochloric acid aqueous solution with a concentration of 0.02 mol / L is atomized and sprayed on the surface of the aluminum foil. The amount of the atomized hydrochloric acid aqueous solution is 1.5 g / m 2 After the acid etching for 300s, the product was rinsed three times with distilled water and dried. The other steps were the same as those in Example 1.

[0107] Performance Testing: Preparation of Drag Chain Flexible Cable Specimens: Drag chain flexible cable specimens consist of four strands of ultrafine copper wire, each with a diameter of 1.2 mm. The ultrafine copper wires are finely twisted into bundles of multiple ultrafine bare copper wires, using the ultrafine copper wire stranding method in accordance with VDE 0295, Class 6. Each strand of ultrafine copper wire is insulated with 0.8 mm thick PP core wire. The four strands of ultrafine copper wire are twisted with two strands of 200D nylon yarn, and then covered with a 1 mm thick PUR inner sheath. The outer surface of the PUR inner sheath is then coated with graphene conductive aluminum foil to produce a semi-finished product. This semi-finished product is then covered with a 2 mm thick PUR outer sheath to produce the 5.5 mm diameter drag chain flexible cable specimen.

[0108] 1. Test method for bending resistance: At a bending radius of 7x the cable diameter, the cables are cyclically bent for 2 million, 3 million, 4 million, and 5 million times. The interlayer structure of the graphene conductive aluminum foil in the drag chain flexible cable sample is observed after 2 million, 3 million, 4 million, and 5 million cycles of bending, respectively. The cyclic bending test ends when interlayer shedding or peeling of the matrix shielding layer and the graphene reinforced shielding layer in the graphene conductive aluminum foil is observed. The cyclic bending test ends when cracks or damage are observed in the graphene conductive aluminum foil. The number of cyclic bending cycles of the drag chain flexible cable sample (10,000 times) is recorded. The number of drag chain flexible cable samples tested in the same batch is 5. When the number of drag chain flexible cable samples tested is ≥ 4, the drag chain flexible cable sample is considered to have qualified the bending resistance under the cyclic bending number (10,000 times).

[0109] 2. Anti-electromagnetic interference performance test method:

[0110] 2.1 The conductive aluminum foil (25 μm thick) in the control group was made into a drag chain flexible cable sample, and the drag chain flexible cable sample was energized at 36 V. The electromagnetic field strength of the outer layer of the drag chain flexible cable sample was measured to be H1. Then, the electromagnetic field strength of the outer layer of the drag chain flexible cable sample made of graphene conductive aluminum foil in Examples 1-14 and Comparative Examples 1-8 was tested to be Hn.

[0111] Characterization of anti-magnetic field interference performance: △H(%)=(Hn-H1) / H1.

[0112] 2.2. The conductive aluminum foil (25 μm thick) in the control group was made into a drag chain flexible cable sample, and the drag chain flexible cable sample was energized at 36 V. The electromagnetic field strength of the outer layer of the drag chain flexible cable sample was measured to be E1. Then, the electromagnetic field strength of the outer layer of the drag chain flexible cable sample made of graphene conductive aluminum foil in Examples 1-14 and Comparative Examples 1-8 was tested to be En.

[0113] Characterization of anti-electric field interference performance: △E(%)=(En-E1) / E1.

[0114] Data Analysis

[0115] Table 1: Test parameters of the bending resistance of the towline flexible cable samples made of graphene conductive aluminum foil in Examples 1-14 and Comparative Examples 1-15

[0116]

[0117]

[0118] Table 2: Anti-electromagnetic interference performance test parameters of the drag chain flexible cable samples made of graphene conductive aluminum foil in Examples 1-14 and Comparative Examples 1-15

[0119]

[0120]

[0121] From Examples 1-14 and Comparative Examples 1-8 and Table 1-2, it can be seen that the hydroxylated graphene preferably accounts for 10-25 wt% of the total mass of the hydroxylated graphene-modified polyurethane. Too low an addition amount will affect the anti-electromagnetic field shielding performance of the graphene conductive aluminum foil, and too much addition amount will affect the service life of the drag chain flexible cable.

[0122] Combining Examples 1-14 and Comparative Examples 1-8 with Table 1-2, it can be seen that the groove structure formed on the surface of the aluminum foil after acid etching can improve the bonding stability of the matrix shielding layer and the graphene enhanced shielding layer, thereby helping to improve the cyclic bending service life of the drag chain flexible cable. The concentration of the hydrochloric acid aqueous solution used in the acid etching treatment needs to be strictly controlled, and the preferred concentration range is 0.1-0.5 mol / L. If the concentration of the hydrochloric acid aqueous solution is too low, the surface of the aluminum foil will not be thoroughly etched, and the bonding stability of the matrix shielding layer and the graphene enhanced shielding layer will still be biased, which cannot meet the requirements of the cyclic bending service life of the drag chain flexible cable; and if the concentration of the hydrochloric acid aqueous solution is too high, the aluminum foil will be corroded, which will destroy the overall anti-electromagnetic field shielding performance of the graphene conductive aluminum foil.

[0123] Combining Examples 1-14 and Comparative Examples 1-8 with Table 1-2 reveals that after acid etching to form a grooved structure on the aluminum foil surface and then subjecting the aluminum foil surface to low-temperature plasma treatment, the bond between the base shielding layer and the graphene-enhanced shielding layer is more stable. Subsequent extreme bending performance testing of the drag chain flexible cable specimens from Examples 9-10 revealed that Example 10 could withstand 6 million bending cycles, while Example 9 could only withstand 5 million.

[0124] Combining Examples 1-14 and Comparative Examples 1-8 and Table 1-2, it can be seen that the research on special aluminum foil shows that the aluminum foil made of single-atom aluminum-modified graphene has better anti-electromagnetic field shielding performance and the number of cyclic bending times can reach 5 million times, which meets the requirements of the cyclic bending service life of the drag chain flexible cable.

[0125] From Examples 1-14 and Comparative Examples 1-8 and Table 1-2, it can be seen that the drag chain flexible cable samples tested in Example 10 and Example 12 were subjected to extreme bending performance tests. The number of cyclic bendings of Example 10 can reach 6 million times, while the number of cyclic bendings of Example 12 is 6 million times. When the number of cyclic bendings is 7 million times, two of the five groups of drag chain flexible cable samples have reached the requirement of 7 million cyclic bendings, while Example 10 does not meet the requirement of 7 million cyclic bendings. It can be seen that the combination stability of the base shielding layer and the graphene enhanced shielding layer in the graphene conductive aluminum foil of Example 12 is better.

[0126] From Example 1 and Example 13 and Table 1-2, it can be seen that the flexible cable for drag chains prepared using the graphene conductive aluminum foil in Example 13 has better cyclic bending performance and better electromagnetic field shielding performance, meeting the shielding performance requirements of the flexible cable for drag chains.

[0127] Combining Example 13 and Example 14 and Tables 7-8, it can be seen that the aluminum-coated TPU film also needs to undergo surface acid etching modification treatment, otherwise it will affect the bonding stability between the aluminum-coated TPU film and the graphene enhanced shielding layer. Based on the aluminum-coated TPU film, the optimal concentration of the acid etching solution is controlled to be 0.1-0.3 mol / L hydrochloric acid aqueous solution. Double 0.15 mol / L hydrochloric acid aqueous solution acid etching treatment can also be selected to ensure that the aluminum layer on the aluminum-coated TPU film forms grooves, thereby improving the bonding stability between the aluminum-coated TPU film and the graphene enhanced shielding layer.

[0128] According to different customers' requirements for the flexibility and low-temperature resistance of drag chain flexible cables, choose graphene conductive aluminum foil type I composed of economical aluminum foil / graphene reinforced shielding layer, or graphene conductive aluminum foil type II composed of aluminized TPU film / graphene reinforced shielding layer with good flexibility and low-temperature resistance.

[0129] In summary, the graphene conductive aluminum foil provided in the present invention has excellent anti-electromagnetic interference performance. The prepared drag chain flexible cable has a cyclic bending radius of 7x the cable diameter of ≥4 million times, which meets the shielding material requirements of drag chain flexible cables for industrial robots.

[0130] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A graphene conductive aluminum foil for a drag chain flexible cable, characterized by: The graphene conductive aluminum foil is used in a drag chain flexible cable as a shielding material of the drag chain flexible cable; the graphene conductive aluminum foil includes a base shielding layer and a graphene reinforced shielding layer, and the thickness of the graphene reinforced shielding layer is equal to 0.2-1.0 times the thickness of the base shielding layer; The base shielding layer is aluminum foil or aluminized flexible polymer resin film; The graphene-enhanced shielding layer is prepared by curing hydroxylated graphene-modified polyurethane resin; The hydroxylated graphene modified polyurethane comprises hydroxylated graphene and NCO-terminated polyurethane resin; the hydroxylated graphene accounts for 10-25wt% of the total mass of the hydroxylated graphene modified polyurethane; The NCO-terminated polyurethane resin has a hard segment content of 28-35 wt%, an isocyanate index R value of 1.05-1.15, and a chain extension coefficient f value of 0.87-0.95; When the base shielding layer is aluminum foil with a thickness of 10-25 microns, before the hydroxylated graphene-modified polyurethane resin is coated on the surface of the aluminum foil, it is necessary to perform surface acid etching and low-temperature plasma treatment in sequence. The surface of the aluminum foil is acid-etched to form a gully structure. The surface of the aluminum foil is then subjected to low-temperature plasma treatment to generate active functional groups. The gully structure formed on the surface of the aluminum foil increases the contact area between the aluminum foil and the graphene-enhanced shielding layer. The active functional groups on the surface of the aluminum foil are chemically bonded to the NCO-terminated polyurethane resin in the hydroxylated graphene-modified polyurethane, thereby improving the bonding stability between the graphene-enhanced shielding layer and the base shielding layer. The aluminum foil comprises an 8-series aluminum alloy and surface-modified graphene, wherein the content of the surface-modified graphene is 0.25-2.0 wt %. The surface-modified graphene comprises graphene as a carrier and modified particles supported on the surface of the graphene, wherein the modified particles are nano-scale aluminum metal clusters and / or single-atom aluminum. The modified particle loading rate in the surface-modified graphene is ≥4.0 wt %. The preparation method of surface-modified graphene is as follows: 200 mg of hydroxylated graphene is weighed and dispersed in 200 mL of deionized water to obtain a graphene dispersion; 1.2 g of KOH is weighed and dissolved in 200 mL of deionized water to obtain a KOH solution; the KOH solution is added dropwise to the graphene dispersion, stirred and dried at 80° C. to obtain a graphene / KOH dry powder; 1 g of AlCl3 is weighed and placed in a crucible, and 1.4 g of graphene / KOH dry powder is placed in the crucible; the crucible containing AlCl3 and the crucible containing graphene / KOH dry powder are placed in the upstream and downstream areas of a tube furnace, respectively, and the tube furnace is sealed; Ar gas is introduced into the tube furnace, and Under Ar atmosphere, the upstream temperature zone of the tube furnace was heated from room temperature to 450°C at a heating rate of 10°C / min and kept warm for 1 hour. At the same time, the downstream temperature zone of the tube furnace was heated to 630°C at a heating rate of 14°C / min and kept warm for 1 hour to obtain a metal single atom-doped graphene precursor; the obtained metal single atom-doped graphene precursor was added to 100 ml of 1 mol / L dilute hydrochloric acid, stirred, vacuum filtered, washed, and dried to obtain surface-modified graphene.

2. The graphene conductive aluminum foil for a drag chain flexible cable according to claim 1, characterized in that: The aluminum foil includes 8011 series aluminum alloy and surface-modified graphene, and the content of the surface-modified graphene is 0.8-1.2wt%. The surface-modified graphene includes graphene as a carrier and modified particles loaded on the surface of the graphene, and the modified particles are monatomic aluminum, which is anchored to defect sites on the surface of the graphene. The loading rate of the monatomic aluminum in the surface-modified graphene is 5.0wt%.

3. The graphene conductive aluminum foil for a drag chain flexible cable according to claim 1, characterized in that: When the base shielding layer is an aluminum-plated flexible polymer resin film, the aluminum-plated flexible polymer resin film includes an aluminum-plated film layer and a flexible polymer resin film, and the flexible polymer resin film is any one of TPU, TPEE, TPV, TPSiV, TPO, TPS, TPAE, PET, SEBS, and EVA; the thickness of the flexible polymer resin film is 50-200 microns; the thickness of the aluminum-plated film layer is 5-20 microns.

4. The graphene conductive aluminum foil for a drag chain flexible cable according to claim 3, characterized in that: When the base shielding layer is an aluminum-plated flexible polymer resin film, the surface needs to be acid-etched before the hydroxylated graphene-modified polyurethane resin is coated on the aluminum-plated flexible polymer resin film. The surface of the aluminum-plated film forms a groove structure after acid etching. The thickness of the aluminum-plated film layer in the aluminum-plated flexible polymer resin film is 10-20 microns. The groove structure formed on the surface of the aluminum-plated film after acid etching increases the contact area between the aluminum-plated flexible polymer resin film and the graphene enhanced shielding layer, thereby improving the bonding stability between the graphene enhanced shielding layer and the base shielding layer.

5. The graphene conductive aluminum foil for a drag chain flexible cable according to claim 3 or 4, characterized in that: The aluminized flexible polymer resin film is an aluminized TPU film with a Shore hardness of 80-90A, the TPU film thickness is 100±5 microns, and the aluminized film layer thickness is 15-20 microns.

6. A process for preparing the graphene conductive aluminum foil for a drag chain flexible cable according to claim 2, characterized in that: The following steps are involved: Step 1, preparation of hydroxylated graphene-modified polyurethane; Step 2: The surface of the aluminum foil is subjected to surface modification treatment, which is acid etching treatment. The specific operation of the acid etching treatment is as follows: preparing a hydrochloric acid aqueous solution with a concentration of 0.1-0.5 mol / L, atomizing the hydrochloric acid aqueous solution with a concentration of 0.1-0.5 mol / L and spraying it on the surface of the aluminum foil, the amount of the atomized hydrochloric acid aqueous solution is 1-3 g / m2, and after acid etching for 300-360 seconds, rinsing with distilled water at least three times and drying; Alternatively, the surface modification treatment further includes low-temperature plasma treatment, wherein the specific operation of the low-temperature plasma treatment is as follows: the aluminum foil that has been subjected to acid etching is placed in a low-temperature plasma treatment apparatus, the power is adjusted to 800-1000W, the gas pressure is adjusted to 0.20-0.25MPa, the working gas is nitrogen, and the treatment time is 200-400s. After the low-temperature plasma treatment is completed, the aluminum foil is rinsed with distilled water for at least three times and then dried. Step 3: Apply the hydroxylated graphene-modified polyurethane prepared in step 1 to the surface of the aluminum foil that has been surface-modified in step 2, place it at 80-120° C. for 2-4 hours, and cool it to room temperature to obtain the graphene conductive aluminum foil for drag chain flexible cables.

7. A process for preparing the graphene conductive aluminum foil for a drag chain flexible cable according to claim 5, characterized in that: The following steps are involved: Step 1, preparation of hydroxylated graphene-modified polyurethane; Step 2: The surface of the aluminum-coated flexible polymer resin film is subjected to surface modification treatment, wherein the surface modification treatment is an acid etching treatment, and the specific operation of the acid etching treatment is as follows: preparing a hydrochloric acid aqueous solution with a concentration of 0.1-0.5 mol / L, atomizing the hydrochloric acid aqueous solution with a concentration of 0.1-0.5 mol / L and spraying it on the surface of the aluminum-coated flexible polymer resin film, wherein the amount of the atomized hydrochloric acid aqueous solution is 1-3 g / m2, and after the acid etching treatment for 300-360 seconds, rinsing with distilled water at least three times and drying; Step three, apply the hydroxylated graphene-modified polyurethane prepared in step one on the surface of the aluminum-coated flexible polymer resin film that has completed the surface modification treatment in step two, place it at 65-95°C for 4-8 hours, and cool it to room temperature to obtain the graphene conductive aluminum foil for drag chain flexible cables.

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