Flame-retardant fireproof cable suitable for quantum computing equipment and preparation method of flame-retardant fireproof cable

Abstract

The invention provides a flame-retardant fireproof cable suitable for quantum computing equipment and a preparation method of the flame-retardant fireproof cable, and belongs to the technical field of fireproof cables. The cable comprises a conductor, an insulating layer, a shielding layer, a flame-retardant layer and a sheath layer from inside to outside. The conductor layer is made of single crystal copper or silver and plated with a gold / palladium layer, the insulating layer is made of polytetrafluoroethylene and nano silicon dioxide, the shielding layer is of a double-layer structure of a graphene film and a silver-plated copper net, the flame-retardant layer is composed of an organic silicon flame retardant, a phosphorus flame retardant, nano paraffin and a polymer matrix material, and the sheath layer is made of thermoplastic polyurethane containing carbon nanotubes. The preparation method comprises the steps of polishing and plating, melt extrusion, hot-pressing weaving, solution coating and the like. The elongation at break of the cable at-196 DEG C is greater than or equal to 300%, the oxygen index is greater than or equal to 32%, the shielding effectiveness of 100MHz-10GHz is greater than or equal to 70dB, the signal distortion rate is less than or equal to 5%, and the cable has the advantages of extremely low temperature adaptability, efficient flame retardance and electromagnetic shielding.

Description

Technical Field

[0001] The present invention relates to the technical field of fireproof cables, and in particular to a flame-retardant and fireproof cable suitable for quantum computing equipment and a preparation method thereof. Background Art

[0002] Against the backdrop of the rapid development of modern science and technology, quantum computing places stringent demands on the performance of electrical connection cables. Fire resistance, a key indicator for ensuring the safe operation of equipment, has become one of the core challenges of technological development. Quantum computing equipment requires core components to be cooled to an extremely low temperature near absolute zero. Traditional flame-retardant materials rapidly lose their flexibility and elasticity at these temperatures, becoming brittle and cracking, which damages the cable structure and, in turn, affects the normal operation of the equipment. Furthermore, the high level of integration and sophisticated circuitry within the equipment make it extremely sensitive to fire hazards. If a cable catches fire due to a short circuit, overload, or other factors, it would not only directly damage the quantum computing system but could also lead to incalculable scientific research losses. Furthermore, the weak quantum-level electromagnetic signals generated during equipment operation are highly susceptible to external interference, placing extremely high demands on the cable's electromagnetic shielding performance. Traditional cables often struggle to meet the requirements for efficient electromagnetic shielding while meeting fire resistance and flame retardancy requirements. While the metal shielding of conventional cables effectively protects against conventional electromagnetic interference, due to the unique physical properties of quantum signals, such as wave-particle duality and quantum tunneling, the metal shielding can interact with the quantum signal, generating quantum tunneling or quantum entanglement interference. This can distort the quantum signal and affect the accuracy of quantum computing results. Furthermore, existing metal shielding structures are easily damaged by high-temperature combustion, making them ineffective in forming a sustained and effective fire barrier and, therefore, unable to meet the stringent fire-retardant requirements of quantum computing equipment. In summary, it is urgent to develop a new type of flame-retardant and fire-proof cable and its preparation technology that can meet the needs of quantum computing equipment. Summary of the Invention

[0003] In order to solve the above-mentioned defects and deficiencies in the prior art, the present application aims to provide a flame-retardant and fire-proof cable suitable for quantum computing equipment and a preparation method thereof.

[0004] One of the objectives of the present invention is to provide a flame-retardant and fireproof cable suitable for quantum computing equipment, wherein the flame-retardant and fireproof cable comprises, from the inside to the outside, a conductor, an insulating layer wrapped around the outside of the conductor, a shielding layer wrapped around the outside of the insulating layer, a flame-retardant layer wrapped around the outside of the shielding layer, and a sheath layer wrapped around the outside of the flame-retardant layer; The conductor is made of single crystal copper or single crystal silver, and the surface of the conductor is plated with a gold layer or a palladium layer; The insulating layer is composed of polytetrafluoroethylene and nano-silicon dioxide; The shielding layer includes: a graphene film coated on the outside of the insulating layer and a silver-plated copper mesh coated on the outside of the graphene film; The flame retardant layer is composed of an organic silicon flame retardant, a phosphorus flame retardant, nano paraffin and a polymer matrix material; The sheath layer consists of thermoplastic polyurethane and carbon nanotubes.

[0005] Preferably, the purity of the single crystal copper or single crystal silver is not less than 99.9999%, and the thickness of the gold layer or palladium layer is 0.1-0.5 μm.

[0006] Preferably, the insulating layer is composed of polytetrafluoroethylene and nano-silicon dioxide; The mass ratio of the polytetrafluoroethylene to the nano-silicon dioxide is (90-95): (5-10).

[0007] Preferably, the number of layers of the graphene film is 1-3, and the film thickness does not exceed 1 nm; the weaving density of the silver-plated copper mesh is 200-300 meshes, and the thickness of the silver-plated layer is 1-3 μm.

[0008] Preferably, the mass ratio of the organosilicon flame retardant to the phosphorus flame retardant is (60-70): (30-40); and the added amount of the nano paraffin is 5%-10% of the total mass of the flame retardant layer raw materials.

[0009] Preferably, the polymer matrix material includes one or more of polydimethylsiloxane, vinyl-terminated polydimethylsiloxane, phenylmethylpolysiloxane, hydroxyl-terminated polydimethylsiloxane or amino-modified polysiloxane.

[0010] Preferably, the sheath layer is composed of thermoplastic polyurethane and carbon nanotubes; the added amount of the carbon nanotubes is 5%-8% of the mass of the thermoplastic polyurethane.

[0011] A second object of the present invention is to provide a method for preparing a flame-retardant and fire-resistant cable suitable for quantum computing equipment as described above, which is characterized by comprising the following steps: The surface of single crystal copper or single crystal silver is polished and then plated with a gold layer or a palladium layer to obtain a conductor; Polytetrafluoroethylene and nano-silicon dioxide are mixed evenly and then melted and extruded to obtain an insulating material; the insulating material is evenly coated on the surface of the conductor to form an insulating layer; After laminating the graphene film on the surface of the insulating layer, a silver-plated copper mesh is coated on the surface of the graphene film to form a double-layer shielding layer; The organic silicon flame retardant, phosphorus flame retardant, nano paraffin, polymer matrix material and organic solvent are uniformly mixed to obtain a flame retardant solution; the flame retardant solution is coated on the surface of the shielding layer, and the flame retardant layer is formed after drying and curing; The carbon nanotubes and thermoplastic polyurethane are evenly mixed and then extruded to obtain a sheath material; the sheath material is coated on the surface of the flame retardant layer and cooled and shaped to obtain a flame retardant and fireproof cable suitable for quantum computing equipment.

[0012] Preferably, laminating the graphene film on the surface of the insulating layer includes: The graphene film is bonded to the surface of the insulating layer using a hot pressing process with a hot pressing temperature of 180-220°C, a pressure of 5-10 MPa, and a holding time of 3-5 minutes.

[0013] Preferably, coating the silver-plated copper mesh on the surface of the graphene film includes: coating the silver-plated copper mesh on the outer layer of the graphene film through a braiding machine in a weaving manner of 12-18 spindles, and controlling the braiding angle at 45-60°.

[0014] Preferably, coating the flame retardant solution on the surface of the shielding layer and drying and curing the flame retardant layer comprises: The flame retardant solution is coated on the surface of the shielding layer, and the coating thickness is controlled at 0.1-0.3 mm; after coating, it is placed in an oven at 120-150° C. for drying and curing for 2-4 hours to form a flame retardant layer.

[0015] Beneficial effects of the present invention: The present invention uses high-purity single-crystal copper or silver as a conductor and plates it with a gold layer or a palladium layer, which significantly reduces the resistance and the temperature coefficient of resistance, and reduces the resistance change at extremely low temperatures; at the same time, in the double-layer shielding structure, the graphene film reduces signal transmission interference due to its good compatibility with quantum signals, and the silver-plated copper mesh blocks external electromagnetic interference by enhancing the electromagnetic shielding capability. The two work together internally and externally to ensure the compatibility of quantum signal transmission and enhance the electromagnetic shielding effect, effectively preventing quantum signal distortion and ensuring the stable transmission of weak quantum-level electromagnetic signals in quantum computing devices.

[0016] The carbon nanotubes in the sheath layer are compounded with thermoplastic polyurethane to form a conductive network, which improves the electromagnetic shielding and antistatic properties of the cable; at the same time, the carbon nanotubes in the sheath layer are connected to the silver-plated copper mesh on the outside of the shielding layer to form a "metal mesh-carbon nanotube" composite shielding layer, which enhances the integrity of the shielding structure and reduces the electromagnetic leakage path.

[0017] Nano-silicon dioxide in the insulating layer promotes the formation of a carbon layer, and the flame-retardant layer uses an organic silicon-phosphorus composite flame-retardant material. Through the synergistic effect of gas phase flame retardancy and condensed phase flame retardancy, it can effectively block heat and flames, prevent the spread of fire, and ensure equipment safety.

[0018] The high-purity single-crystal metal and plating layers in the conductor layer reduce resistance at extremely low temperatures, ensuring stable signal transmission. The insulating and flame-retardant layers maintain flexibility at extremely low temperatures, and combined with the flame-retardant properties of nanomaterials, they form a dual fire barrier. The double-layer shielding structure isolates external electromagnetic interference and prevents quantum signal distortion. The conductive network in the sheath layer enhances electromagnetic shielding and antistatic properties, fully meeting the stringent cable requirements of quantum computing devices. The synergistic effect of these layers ensures structural stability in extremely low-temperature environments, providing efficient flame retardancy and fire resistance, while also meeting the requirements for electromagnetic shielding and improving the stability of quantum signal transmission. DETAILED DESCRIPTION

[0019] According to a first aspect of the present invention, there is provided a flame-retardant and fireproof cable suitable for use in quantum computing devices. The flame-retardant and fireproof cable comprises, from the inside out, a conductor, an insulating layer wrapped around the outside of the conductor, a shielding layer wrapped around the outside of the insulating layer, a flame-retardant layer wrapped around the outside of the shielding layer, and a sheath layer wrapped around the outside of the flame-retardant layer. The conductor is made of single crystal copper or single crystal silver, and the surface of the conductor is plated with a gold layer or a palladium layer; The insulating layer is composed of polytetrafluoroethylene and nano-silicon dioxide; The shielding layer includes: a graphene film coated on the outside of the insulating layer and a silver-plated copper mesh coated on the outside of the graphene film; The flame retardant layer is composed of an organic silicon flame retardant, a phosphorus flame retardant, nano paraffin and a polymer matrix material; The sheath layer consists of thermoplastic polyurethane and carbon nanotubes.

[0020] In the present invention, single-crystal copper or silver is selected for its excellent electrical conductivity and extremely low temperature coefficient of resistance. When operating in the extremely low-temperature environment of quantum computing devices, the resistance of ordinary conductors undergoes significant changes, affecting signal transmission. However, single-crystal copper or silver can reduce this resistance change and ensure stable signal transmission. The surface is plated with a gold or palladium layer, taking advantage of the excellent chemical stability of gold and palladium to prevent oxidation of the conductors at extremely low temperatures, further reducing contact resistance and avoiding signal transmission losses caused by oxidation.

[0021] It adopts a double-layer shielding structure. The inner graphene film has excellent electromagnetic shielding performance and quantum signal compatibility. Its unique two-dimensional structure and atomic-level thickness can effectively shield external conventional electromagnetic interference, while avoiding interaction with quantum state signals to prevent quantum tunneling effects or quantum entanglement interference; the outer silver-plated copper mesh further enhances the electromagnetic shielding capability, while providing mechanical protection for the cable to resist external physical damage.

[0022] Silicone materials exhibit excellent flexibility and chemical stability at extremely low temperatures, ensuring that the flame-retardant layer does not brittle or crack in low-temperature environments. Phosphorus-based flame retardants achieve high flame retardancy through the synergistic effects of vapor-phase flame retardancy (capturing free radicals) and condensed-phase flame retardancy (forming char and providing insulation) during combustion. The addition of nano-paraffin wax utilizes its phase-change energy storage function to maintain a solid state at extremely low temperatures, enhancing flexibility. At high temperatures or in fires, it absorbs heat and melts, slowing heat transfer. The polymer matrix material is a polysiloxane polymer with good compatibility with silicone and phosphorus-based flame retardants, ensuring uniform dispersion and synergistic effect of the flame-retardant components.

[0023] In a preferred embodiment of the present invention, the purity of single crystal copper or single crystal silver is not less than 99.9999%, and the thickness of the surface-plated gold layer or palladium layer is 0.1-0.5 μm.

[0024] Ordinary copper and silver conductors contain a large number of grain boundaries, impurities and defects. Electrons are easily scattered at these locations during transmission, thereby increasing resistance and signal loss. In the present invention, single-crystal copper or single-crystal silver with a purity of not less than 99.9999% almost eliminates grain boundaries and greatly reduces electron scattering. Quantum computing equipment has extremely high requirements for the stability of signal transmission. Even tiny resistance fluctuations or impurity interference may cause quantum state collapse and affect the calculation results. High-purity single-crystal copper or silver reduces the interference of impurities on signal transmission from the source, providing a guarantee for the stable operation of the equipment. Gold and palladium have extremely strong chemical stability and are not easily oxidized in the air. In an extremely low temperature environment, although the chemical reaction rate slows down, water vapor, corrosive gases, etc. may still undergo slow oxidation reactions with copper and silver, forming an oxide layer on the surface of the conductor, increasing the contact resistance. Plating a 0.1-0.5μm thick gold or palladium layer is like forming a dense protective film, isolating substances such as air and water vapor, effectively preventing the oxidation of the conductor and ensuring long-term stable operation.

[0025] Gold and palladium inherently possess excellent electrical conductivity. Plating optimizes the electrical properties of the conductor surface, further reducing contact resistance and facilitating smoother current transmission. This is particularly significant for improving transmission efficiency in the low-current and signal transmission scenarios of quantum computing devices. Gold and palladium are precious metals and are relatively expensive. A coating thickness of 0.1-0.5μm ensures adequate oxidation resistance and resistance reduction while also meeting performance requirements while maintaining reasonable cost and overall cable weight. This avoids unnecessary cost increases and compromised cable flexibility due to excessively thick coatings.

[0026] In a preferred embodiment of the present invention, the insulating layer is composed of polytetrafluoroethylene and nano-silicon dioxide; the mass ratio of polytetrafluoroethylene to the nano-silicon dioxide is (90-95): (5-10).

[0027] In this invention, polytetrafluoroethylene (PTFE) maintains excellent flexibility and chemical stability even at extremely low temperatures, meeting the low-temperature requirements of quantum computing devices. Nano-silica is evenly dispersed within the PTFE matrix, forming a nano-reinforced network that enhances the material's mechanical strength and prevents damage to the insulation layer during cable use. Furthermore, the nano-silica promotes the formation of a char layer during combustion, which acts as a heat and flame barrier and enhances the flame retardancy of the insulation layer. PTFE has an extremely low glass transition temperature (approximately -190°C), allowing it to maintain excellent flexibility and chemical stability in the operating environment of quantum computing devices, making it crucial for the insulation layer's low-temperature adaptability. Excessive nano-silica addition can disrupt the PTFE's molecular chain structure, reducing its flexibility and causing brittle cracking at extremely low temperatures. Keeping the PTFE content above 90% ensures that the insulation layer maintains sufficient elongation at break at -196°C, maintaining its physical stability and ensuring the cable's proper operation in low-temperature environments.

[0028] Nanosilica plays a dual role in the insulation layer, both as a flame retardant and a reinforcement. During combustion, nanosilica promotes the formation of a char layer. At high temperatures, it catalyzes the carbonization of polytetrafluoroethylene, forming a dense char layer that blocks the transfer of heat and flames into the cable. Simultaneously, the nanoparticles are evenly dispersed within the polytetrafluoroethylene matrix, forming an effective nano-reinforcement network that significantly improves the material's tensile strength and wear resistance. A nanosilica mass ratio of 5%-10% fully realizes these benefits while avoiding the ineffective effects of too low an addition or the agglomeration of too high an addition, which can reduce the overall performance of the material.

[0029] This mass ratio range is beneficial for the extrusion molding process of the insulation layer material. A high PTFE content provides excellent material flowability, facilitating coating on the conductor surface through a twin-screw extruder. An appropriate amount of nano-silica (5%-10%) achieves uniform dispersion under the shearing action of the screw, avoiding problems such as uneven insulation thickness, surface defects, or extrusion difficulties caused by agglomeration, thereby ensuring insulation layer molding quality and production efficiency.

[0030] In a preferred embodiment of the present invention, the number of graphene film layers is 1-3, and the film thickness does not exceed 1 nm; the weaving density of the silver-plated copper mesh is 200-300 meshes, and the thickness of the silver-plated layer is 1-3 μm.

[0031] In this invention, the graphene film has a unique two-dimensional structure and atomic-level thickness (no more than 1 nm). This structure ensures excellent compatibility with quantum state signals, preventing interaction with them and preventing quantum tunneling or quantum entanglement interference. The number of layers is controlled between 1 and 3, ensuring sufficient electromagnetic shielding capability while minimizing compatibility with quantum signals due to excessive layers. However, excessive layers increase the film thickness, hindering quantum signals and affecting the proper operation of quantum computing devices.

[0032] A single layer of graphene has a certain shielding effect against electromagnetic interference, and as the number of layers increases, the shielding efficiency will increase. The shielding efficiency of a graphene film with 1-3 layers against electromagnetic interference in the 100MHz-10GHz frequency band can be ≥60dB, which can effectively shield conventional external electromagnetic interference and protect the quantum state signals inside the cable from interference. At the same time, the characteristics of the graphene film give it advantages in high-frequency electromagnetic shielding, which can meet the high-frequency electromagnetic shielding needs of quantum computing equipment. The process of preparing graphene film is relatively difficult. Too many layers will increase the difficulty and cost of preparation, and during the hot pressing process with the insulating layer, the uniformity and bonding effect of the multi-layer film are difficult to guarantee. The setting of 1-3 layers takes into account process feasibility and cost control while ensuring performance.

[0033] The silver-plated copper mesh serves as the outer shielding layer, primarily enhancing electromagnetic shielding capabilities. A weave density of 200-300 mesh creates a denser shielding structure, effectively shielding electromagnetic interference across different frequency bands. Working in synergy with the inner graphene film, it significantly enhances the cable's overall electromagnetic shielding performance. If the weave density is too low and the mesh openings are too large, electromagnetic interference can easily penetrate the cable. Excessively high weave density increases cost and cable weight while reducing flexibility. An appropriate weave density imparts mechanical strength to the silver-plated copper mesh, providing mechanical protection against external physical damage, such as extrusion and friction, and safeguarding the internal insulation, shielding, and conductor layers.

[0034] The thickness of the silver plating layer is 1-3μm. On the one hand, silver has good electrical conductivity and electromagnetic shielding properties. Sufficient thickness of the silver plating layer can ensure the stability of the electrical conductivity and shielding properties of the copper mesh, prevent oxidation of the copper mesh, and extend its service life. On the other hand, controlling the thickness within this range can avoid increasing costs and weight due to excessive thickness of the silver plating layer, while ensuring the bonding strength between the silver plating layer and the copper mesh and preventing the silver plating layer from falling off.

[0035] In a preferred embodiment of the present invention, the mass ratio of the organosilicon flame retardant to the phosphorus flame retardant is (60-70): (30-40); the added amount of the nano paraffin is 5%-10% of the total mass of the flame retardant layer raw materials.

[0036] In this invention, the organosilicon flame retardant forms a silicon-oxygen-carbon layer upon combustion, covering the material's surface and blocking oxygen and heat transfer. The phosphorus-based flame retardant decomposes to produce substances such as phosphoric acid and metaphosphoric acid, promoting charring and capturing combustion free radicals. When the mass ratio of the two is (60-70):(30-40), the organosilicon provides a denser and more stable carbon layer, while the phosphorus-based flame retardant promotes rapid char formation. The synergistic effect of the two significantly improves flame retardancy.

[0037] When nanoparaffin wax is added at a level of 5%-10%, it forms uniformly dispersed nanoscale energy storage particles within the material. At extremely low temperatures, the nanoparaffin wax remains solid, filling the polymer matrix and enhancing the material's flexibility and impact resistance. At high temperatures or in the event of a fire, the nanoparaffin wax absorbs heat and melts (with a phase transition temperature of approximately 50-70°C), absorbing a significant amount of latent heat, slowing heat transfer into the cable and reducing the rate of thermal decomposition. Furthermore, the melted nanoparaffin wax acts as a fluid filler during the initial formation of the char layer, further optimizing the char layer structure and enhancing flame retardancy. Within this ratio, the flame retardant exhibits excellent compatibility with polymer matrix materials (such as polysiloxanes), forming a uniform and stable solution in organic solvents, making it easy to apply to the shielding layer via dip coating or spray coating. Excessive silicone flame retardant content increases solution viscosity, making the coating process more difficult. Excessive phosphorus flame retardant content can lead to phase separation, affecting the uniformity of the flame retardant layer. In addition, adding more than 10% nanoparaffin will reduce the mechanical strength of the material, while less than 5% will not fully exert the phase change energy storage effect.

[0038] In a preferred embodiment of the present invention, the polymer matrix material includes one or more of polydimethylsiloxane, vinyl-terminated polydimethylsiloxane, phenylmethylpolysiloxane, hydroxyl-terminated polydimethylsiloxane or amino-modified polysiloxane.

[0039] In the present invention, the polymer matrix material is, for example, polydimethylsiloxane, vinyl-terminated polydimethylsiloxane, phenylmethylpolysiloxane, hydroxy-terminated polydimethylsiloxane, amino-modified polysiloxane, polydimethylsiloxane and vinyl-terminated polydimethylsiloxane, phenylmethylpolysiloxane and hydroxy-terminated polydimethylsiloxane, vinyl-terminated polydimethylsiloxane and phenylmethylpolysiloxane, polydimethylsiloxane, vinyl-terminated polydimethylsiloxane and phenylmethylpolysiloxane, or phenylmethylpolysiloxane, hydroxy-terminated polydimethylsiloxane and amino-modified polysiloxane.

[0040] In a preferred embodiment of the present invention, the sheath layer is composed of thermoplastic polyurethane and carbon nanotubes; the added amount of the carbon nanotubes is 5%-8% of the mass of the thermoplastic polyurethane.

[0041] In this invention, the thermoplastic polyurethane (TPU) possesses excellent low-temperature resistance and mechanical strength, protecting the internal structure from external physical impact. Carbon nanotubes are evenly dispersed within the TPU matrix, forming a conductive network that further enhances the material's electromagnetic shielding and antistatic properties, preventing the effects of static electricity on quantum computing devices. The addition of carbon nanotubes also enhances flame retardancy. The carbon nanotube content is controlled at 5%-8% of the TPU's mass to achieve an optimal balance between electromagnetic shielding, mechanical properties, flame retardancy, and cost control.

[0042] Carbon nanotubes (CNTs) possess excellent electrical conductivity. When added at a concentration of 5% by weight of TPU, the CNTs begin to connect with each other within the TPU matrix, forming a continuous conductive network. Increasing the concentration to 8% further improves the conductive network, resulting in a sheath layer with a volume resistivity of ≤10³Ω·cm. This effectively shields electromagnetic interference (EMI) and rapidly conducts static electricity away from the cable surface, preventing it from affecting quantum computing devices. At concentrations below 5%, the CNTs fail to fully connect, forming an effective conductive network and failing to meet the required electromagnetic shielding and antistatic properties. Above 8%, the CNTs tend to agglomerate, which in turn reduces conductivity and material uniformity.

[0043] An appropriate amount of carbon nanotubes (5%-8%) dispersed in thermoplastic polyurethane can enhance the tensile strength and abrasion resistance of the sheath layer. The high strength and high modulus of carbon nanotubes allow the material to partially absorb stress when subjected to force, thereby improving overall mechanical properties. However, excessive additions can cause carbon nanotube aggregates to become weak points in the material, reducing its toughness and making it more susceptible to cracking, which in turn weakens its mechanical properties.

[0044] During combustion, carbon nanotubes promote the formation of a char layer, synergistically enhancing the flame retardancy of the cable with the flame-retardant layer. Adding 5%-8% carbon nanotubes evenly distributes them within the thermoplastic polyurethane matrix, helping to form a continuous, dense char layer at high temperatures, effectively blocking heat and oxygen transfer. Adding more than this amount can affect the quality of the char layer due to agglomeration, reducing the flame retardant effect.

[0045] As a high-performance nanomaterial, carbon nanotubes are relatively expensive. Adding them at a 5%-8% level can achieve improvements in electromagnetic shielding, mechanical reinforcement, and flame retardancy at a relatively reasonable cost, meeting the performance requirements of quantum computing devices for cable sheaths while avoiding the significant cost increases associated with excessive carbon nanotube addition. This achieves an optimal balance between performance and cost, enhancing the product's market competitiveness.

[0046] According to a second aspect of the present invention, there is provided a method for preparing a flame-retardant and fire-resistant cable suitable for quantum computing equipment as described above, characterized in that it comprises the following steps: The surface of single crystal copper or single crystal silver is polished and then plated with a gold layer or a palladium layer to obtain a conductor; Polytetrafluoroethylene and nano-silicon dioxide are mixed evenly and then melted and extruded to obtain an insulating material; the insulating material is evenly coated on the surface of the conductor to form an insulating layer; After laminating the graphene film on the surface of the insulating layer, a silver-plated copper mesh is coated on the surface of the graphene film to form a double-layer shielding layer; The organic silicon flame retardant, phosphorus flame retardant, nano paraffin, polymer matrix material and organic solvent are uniformly mixed to obtain a flame retardant solution; the flame retardant solution is coated on the surface of the shielding layer, and the flame retardant layer is formed after drying and curing; The carbon nanotubes and thermoplastic polyurethane are evenly mixed and then extruded to obtain a sheath material; the sheath material is coated on the surface of the flame retardant layer and cooled and shaped to obtain a flame retardant and fireproof cable suitable for quantum computing equipment.

[0047] In a preferred embodiment of the present invention, laminating the graphene film on the surface of the insulating layer includes: The graphene film is bonded to the surface of the insulating layer using a hot pressing process with a hot pressing temperature of 180-220°C, a pressure of 5-10 MPa, and a holding time of 3-5 minutes.

[0048] In the present invention, the hot pressing process parameters are used to bond the graphene film in order to ensure good bonding between the film and the insulating layer while avoiding damage to the material properties. 180-220°C can not only enable the surface molecules of the graphene film and the insulating layer to obtain sufficient energy to diffuse and penetrate each other, thereby enhancing the interfacial bonding strength, but also be lower than the decomposition temperature of insulating layer materials such as polytetrafluoroethylene, thereby preventing the material from being degraded due to overheating and ensuring the insulation performance. A pressure of 5-10MPa ensures that the graphene film and the insulating layer are tightly bonded, eliminating bubbles and gaps between the two, forming a continuous shielding layer, and improving the electromagnetic shielding effect; at the same time, it avoids excessive pressure that may damage the two-dimensional structure of the graphene film or deform the insulating layer. 3-5min ensures sufficient interaction between molecules, making the bonding firm and stable; if the time is too short, the bonding is insufficient, and if it is too long, the production efficiency is reduced and it may have an adverse effect on the material properties.

[0049] In a preferred embodiment of the present invention, coating the silver-plated copper mesh on the surface of the graphene film includes: coating the silver-plated copper mesh on the outer layer of the graphene film through a braiding machine in a weaving manner of 12-18 spindles, and controlling the braiding angle at 45-60°.

[0050] In the present invention, a weaving number of 12-18 spindles can form a mesh structure with moderate density, which can form multiple reflections and absorptions for electromagnetic interference in different frequency bands. When the weaving angle is 45-60°, the copper mesh grid is distributed in a diamond shape. This structure can effectively increase the propagation path of electromagnetic waves in the shielding layer, improve the shielding efficiency for electromagnetic interference in the 100MHz-10GHz frequency band, and synergize with the inner graphene film to achieve an overall shielding effectiveness of ≥70dB. If the weaving angle is too small, the mesh tends to be square, and electromagnetic waves can easily penetrate through the mesh gaps; if the weaving angle is too large, the coverage of the copper mesh will be reduced, weakening the shielding effect. Under this weaving parameter, the silver-plated copper mesh can provide sufficient mechanical protection for the cable to resist external physical impact (such as stress during bending and stretching), while maintaining the overall flexibility of the cable. The weaving method of 12-18 spindles is easy to implement in industrial production, with moderate equipment requirements and energy consumption. Controlling the braiding angle at 45-60° can avoid material waste and reduced production efficiency due to overly dense braiding, while ensuring that the silver-plated copper mesh and the inner graphene film fit tightly together, preventing delamination during subsequent processing or use, and ensuring the stability of cable quality.

[0051] In a preferred embodiment of the present invention, coating the flame retardant solution on the surface of the shielding layer and drying and curing the flame retardant layer comprises: The flame retardant solution is coated on the surface of the shielding layer, and the coating thickness is controlled at 0.1-0.3 mm; after coating, it is placed in an oven at 120-150° C. for drying and curing for 2-4 hours to form a flame retardant layer.

[0052] In the present invention, a thickness of 0.1-0.3mm enables sufficient distribution of effective ingredients such as silicone flame retardants and phosphorus flame retardants in the flame retardant layer. When the cable encounters a fire, a flame retardant layer of this thickness can form a continuous and dense carbonized layer, achieving a synergistic effect of gas phase flame retardancy and condensed phase flame retardancy. For example, nano paraffin can be evenly dispersed within this thickness range, giving full play to the phase change heat absorption function at high temperatures, delaying heat transfer, and ensuring that the integrity of the carbon layer is maintained at ≥80%. If the thickness is too thin, the flame retardant component is insufficient and an effective flame retardant barrier cannot be formed; if it is too thick, the weight and cost of the cable will increase, and flexibility may be affected. This coating thickness can meet the flame retardant requirements without significantly increasing the outer diameter of the cable, ensuring that the overall outer diameter of the cable is controlled at 3-8mm, maintaining compatibility with the internal space of the quantum computing device, while avoiding the reduction in cable bending performance due to excessive thickness, affecting wiring installation.

[0053] A drying temperature of 120-150°C allows the organic solvent in the flame retardant solution to fully evaporate, while also promoting a cross-linking reaction between the polymer matrix material and the flame retardant, forming a stable three-dimensional network structure. Temperatures below 120°C prevent sufficient solvent evaporation and incomplete cross-linking, resulting in insufficient strength and stability of the flame retardant layer. Temperatures above 150°C may cause decomposition of ingredients such as the silicone flame retardant, reducing flame retardant properties. A drying and curing time of 2-4 hours ensures the cross-linking reaction is fully complete, giving the flame retardant layer good mechanical strength and adhesion. Too short a drying time results in incomplete cross-linking, and the flame retardant layer is prone to shedding and cracking. Too long a drying and curing time reduces production efficiency and increases energy costs.

[0054] In the present invention, the preparation method of the flame retardant and fireproof cable suitable for quantum computing equipment specifically includes: Polish single crystal copper or single crystal silver conductors with a purity of not less than 99.9999% to remove the surface oxide layer and impurities; then use vacuum evaporation or electroplating technology to plate a 0.1-0.5μm thick gold or palladium layer on the surface of the conductor, and control the current density to 1-3A / dm during the plating process. 2 , the temperature is maintained at 30-50℃ and the pH value of the plating solution is maintained at 4-6 to ensure a uniform and dense coating; Polytetrafluoroethylene and nano-silica are added into a high-speed mixer in a mass ratio of (90-95): (5-10) and mixed at 80-100°C for 10-15 minutes. The mixed materials are melt-extruded through a twin-screw extruder at a temperature of 320-360°C and a screw speed of 150-200 r / min to evenly coat the conductor surface with the insulating material to form an insulating layer. First, a graphene film with 1-3 layers and a thickness of no more than 1nm is bonded to the surface of the insulating layer using a hot pressing process. The hot pressing temperature is 180-220°C, the pressure is 5-10MPa, and the holding time is 3-5min. Then, a silver-plated copper mesh with a weaving density of 200-300 mesh and a silver-plated layer thickness of 1-3μm is wrapped around the outer layer of the graphene film using a weaving machine in a 12-18 spindle weaving manner. The weaving angle is controlled at 45-60° to form a double-layer shielding layer. According to the mass ratio of organic silicon flame retardant to phosphorus flame retardant of 60-70:30-40, and the addition amount of nano paraffin is 5%-10% of the total mass of the raw materials of the flame retardant layer, the organic silicon flame retardant, phosphorus flame retardant, nano paraffin and polymer matrix material are added to the organic solvent toluene or xylene, and stirred at 50-70°C for 2-3 hours to form a uniform solution; the solution is coated on the surface of the shielding layer by dip coating or spraying process, and the coating thickness is controlled to be 0.1-0.3mm; after coating, it is placed in an oven at 120-150°C for drying and curing for 2-4 hours to form a flame retardant layer; The carbon nanotubes are added to thermoplastic polyurethane at a ratio of 5% to 8% by mass of the thermoplastic polyurethane, and mixed in a high-speed mixer at a speed of 800-1000 r / min for 15-20 minutes; the mixture is extruded through a single-screw extruder with the extrusion temperature set at 180-220°C and the screw aspect ratio of 28-32, and the sheath material is coated on the surface of the flame retardant layer; immediately after extrusion and coating on the surface of the flame retardant layer, a water cooling device is used for rapid cooling, and the cooling water temperature is controlled at 10-20°C, so that the sheath is quickly shaped to form a complete flame retardant and fireproof cable.

[0055] The present application will be further described in detail below in conjunction with the embodiments. The specific embodiments described herein are only used to explain the relevant invention, and are not intended to limit the invention. In the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below in conjunction with the embodiments. Example 1 The method for preparing a flame-retardant and fire-resistant cable suitable for quantum computing equipment in this embodiment includes: After polishing the single crystal copper conductor, the copper conductor was plated in a 30℃, pH=4 solution at 1A / dm 2 The current density was 200 nm to electroplate a 0.1 μm gold layer.

[0056] 95 parts of polytetrafluoroethylene and 5 parts of nano-silicon dioxide were mixed at 80°C for 10 minutes, extruded through a twin-screw extruder at 320°C and 150 r / min, and coated on the conductor to form an insulating layer; A layer of graphene film is hot-pressed at 180°C and 5MPa for 3 minutes to bond to the insulation layer, and then covered with a 200-mesh silver-plated copper mesh with 12 spindles and a 45° braid angle to form a double-layer shielding layer; 60 parts of polymethylhydrogensiloxane, 40 parts of dimethyl methylphosphonate, 5 parts of nano paraffin and polydimethylsiloxane were dissolved in toluene, stirred at 50°C for 2 hours, coated with 0.1mm and cured at 120°C for 2 hours to form a flame retardant layer; 5% carbon nanotubes and thermoplastic polyurethane were mixed at 800r / min for 15min, extruded by a single screw at 180℃ and coated on the surface of the flame retardant layer, and then water-cooled at 10℃ to obtain a flame retardant and fireproof cable suitable for quantum computing equipment.

[0057] Example 2 The method for preparing a flame-retardant and fire-resistant cable suitable for quantum computing equipment in this embodiment includes: After polishing, the single crystal silver conductor is plated at 2A / dm in a 40℃, pH=5 bath. 2 The current density was used to electroplate a 0.3 μm palladium layer; 92 parts of polytetrafluoroethylene and 8 parts of nano-silicon dioxide were mixed at 90°C for 12 minutes, extruded through a twin-screw extruder at 340°C and 180 r / min, and coated on the conductor to form an insulating layer; Two layers of graphene film are hot-pressed at 200°C and 8MPa for 4 minutes to form an insulating layer, and then covered with a 250-mesh silver-plated copper mesh with a 15-spindle, 50-degree braid angle to form a double-layer shielding layer. 65 parts of polymethylhydrogensiloxane, 35 parts of dimethyl methylphosphonate, 7 parts of nano paraffin and vinyl-terminated polysiloxane were dissolved in xylene, stirred at 60°C for 2.5 hours, coated with 0.2 mm and cured at 130°C for 3 hours to form a flame retardant layer; 6% carbon nanotubes and thermoplastic polyurethane were mixed at 900r / min for 18min, extruded by a single screw at 200℃ and coated on the surface of the flame retardant layer, and then water-cooled at 15℃ to obtain a flame retardant and fireproof cable suitable for quantum computing equipment.

[0058] Example 3 The method for preparing a flame-retardant and fire-resistant cable suitable for quantum computing equipment in this embodiment includes: After polishing, single crystal copper was plated in a 50℃, pH=6 bath at 3A / dm 2 Current density electroplating 0.5μm gold layer; 90 parts of polytetrafluoroethylene and 10 parts of nano-silicon dioxide were mixed at 100°C for 15 minutes, extruded through a twin-screw extruder at 360°C and 200 r / min, and coated on the conductor to form an insulating layer; Three layers of graphene film are hot-pressed at 220°C and 10 MPa for 5 minutes to form an insulating layer, and then covered with a 300-mesh silver-plated copper mesh with 18 spindles and a 60° braid angle to form a double-layer shielding layer; 70 parts of polymethylhydrogensiloxane, 30 parts of dimethyl methylphosphonate, 10 parts of nano paraffin and phenyl methyl polysiloxane were dissolved in toluene, stirred at 70°C for 3 hours, coated with 0.3mm and cured at 150°C for 4 hours to form a flame retardant layer; 7% carbon nanotubes and thermoplastic polyurethane were mixed at 1000r / min for 20min, extruded by single screw at 220℃, coated on the surface of flame retardant layer, and water-cooled at 20℃ to obtain flame retardant and fireproof cables suitable for quantum computing equipment.

[0059] Example 4 The method for preparing a flame-retardant and fire-resistant cable suitable for quantum computing equipment in this embodiment includes: After polishing, single crystal copper was plated in a 35℃, pH=4.5 bath at 1.5A / dm 2 The current density was used to electroplate a 0.2 μm palladium layer; 94 parts of polytetrafluoroethylene and 6 parts of nano-silicon dioxide were mixed at 85°C for 11 minutes, extruded through a twin-screw extruder at 330°C and 160 r / min, and coated on the conductor to form an insulating layer; A layer of graphene film is hot-pressed at 190°C and 6MPa for 3.5 minutes to bond to the insulation layer, and then covered with a 250-mesh silver-plated copper mesh with 13 spindles and a 48° braid angle to form a double-layer shielding layer; 62 parts of polymethylhydrogensiloxane, 38 parts of dimethyl methylphosphonate, 6 parts of nano paraffin and hydroxyl-terminated polysiloxane were dissolved in xylene, stirred at 55°C for 2.2 hours, coated with 0.15mm and cured at 125°C for 2.5 hours to form a flame retardant layer; 5% carbon nanotubes and thermoplastic polyurethane were mixed at 850r / min for 16 minutes, extruded by single screw at 190℃, coated on the surface of the flame retardant layer, and water-cooled at 12℃ to obtain flame-retardant and fire-proof cables suitable for quantum computing equipment.

[0060] Example 5 The method for preparing a flame-retardant and fire-resistant cable suitable for quantum computing equipment in this embodiment includes: After polishing, single crystal silver was plated in a 45℃, pH=5.5 bath at 2.5A / dm 2 Current density electroplating 0.4μm gold layer; 93 parts of polytetrafluoroethylene and 7 parts of nano-silicon dioxide were mixed at 95°C for 13 minutes, extruded through a twin-screw extruder at 350°C and 190 r / min, and coated on the conductor to form an insulating layer; Two layers of graphene film are hot-pressed at 210°C and 9MPa for 4.5 minutes to form an insulating layer, and then covered with a 300-mesh silver-plated copper mesh with 17 spindles and a 55° braid angle to form a double-layer shielding layer; 68 parts of polymethylhydrogensiloxane, 32 parts of dimethyl methylphosphonate, 8 parts of nano paraffin and amino-modified polysiloxane were dissolved in toluene, stirred at 65°C for 2.8 hours, coated with 0.25mm and cured at 140°C for 3.5 hours to form a flame retardant layer; 8% carbon nanotubes and thermoplastic polyurethane were mixed at 950r / min for 19 minutes, extruded by single screw at 210℃, coated on the surface of the flame retardant layer, and water-cooled at 18℃ to obtain a flame retardant and fireproof cable suitable for quantum computing equipment.

[0061] Example 6 The method for preparing a flame-retardant and fire-resistant cable suitable for quantum computing equipment in this embodiment includes: After polishing, single crystal copper was plated in a 40℃, pH=5 bath at 2A / dm 2 The current density was used to electroplate a 0.3 μm palladium layer; 91 parts of polytetrafluoroethylene and 9 parts of nano-silicon dioxide were mixed at 90°C for 12 minutes, extruded through a twin-screw extruder at 340°C and 180 r / min, and coated on the conductor to form an insulating layer; Three layers of graphene film are hot-pressed at 200°C and 8MPa for 4 minutes to form an insulating layer, and then covered with a 200-mesh silver-plated copper mesh with 12 spindles and a 45° braid angle to form a double-layer shielding layer; 64 parts of polymethylhydrogensiloxane, 36 parts of dimethyl methylphosphonate, 9 parts of nano paraffin and polydimethylsiloxane were dissolved in xylene, stirred at 60°C for 2.5 hours, coated with 0.2mm and cured at 130°C for 3 hours to form a flame retardant layer; 6% carbon nanotubes and thermoplastic polyurethane were mixed at 900r / min for 18min, extruded by single screw at 200℃, coated on the surface of flame retardant layer, and water-cooled at 15℃ to obtain flame retardant and fireproof cables suitable for quantum computing equipment.

[0062] Example 7 The method for preparing a flame-retardant and fire-resistant cable suitable for quantum computing equipment in this embodiment includes: After polishing, single crystal silver was plated in a 35℃, pH=4.5 bath at 1.8A / dm 2 A 0.2 μm gold layer was electroplated at a current density of 100 nm.

[0063] 95 parts of polytetrafluoroethylene and 5 parts of nano-silicon dioxide were mixed at 80°C for 10 minutes, extruded through a twin-screw extruder at 320°C and 150 r / min, and coated on the conductor to form an insulating layer; Two layers of graphene film are hot-pressed at 190°C and 7MPa for 3.5 minutes to form an insulating layer, and then covered with a 220-mesh silver-plated copper mesh with 14 spindles and a 47° braid angle to form a double-layer shielding layer; 66 parts of polymethylhydrogensiloxane, 34 parts of dimethyl methylphosphonate, 5 parts of nano paraffin and vinyl-terminated polysiloxane were dissolved in toluene, stirred at 58°C for 2.3 hours, coated with 0.18 mm and cured at 128°C for 2.8 hours to form a flame retardant layer; 7% carbon nanotubes and thermoplastic polyurethane were mixed at 980r / min for 17 minutes, extruded by single screw at 210℃, coated on the surface of the flame retardant layer, and water-cooled at 16℃ to obtain flame-retardant and fire-proof cables suitable for quantum computing equipment.

[0064] Example 8 The method for preparing a flame-retardant and fire-resistant cable suitable for quantum computing equipment in this embodiment includes: After polishing, single crystal copper was plated in a 50℃, pH=6 bath at 3A / dm 2 The current density was used to electroplate a 0.5 μm palladium layer; 90 parts of polytetrafluoroethylene and 10 parts of nano-silicon dioxide were mixed at 100°C for 15 minutes, extruded through a twin-screw extruder at 360°C and 200 r / min, and coated on the conductor to form an insulating layer; A layer of graphene film is hot-pressed at 220°C and 10 MPa for 5 minutes to bond to the insulation layer, and then covered with a 280-mesh silver-plated copper mesh with 16 spindles and a 58° braid angle to form a double-layer shielding layer; 70 parts of polymethylhydrogensiloxane, 30 parts of dimethyl methylphosphonate, 10 parts of nano paraffin and phenyl methylpolysiloxane were dissolved in xylene, stirred at 70°C for 3 hours, coated with 0.3mm and cured at 150°C for 4 hours to form a flame retardant layer; 8% carbon nanotubes and thermoplastic polyurethane were mixed at 1000r / min for 20min, extruded by single screw at 220℃ and coated on the surface of flame retardant layer, and water-cooled at 20℃ to obtain flame retardant and fireproof cables suitable for quantum computing equipment.

[0065] Comparative Example 1 The method for preparing a flame-retardant and fire-resistant cable suitable for quantum computing equipment in this embodiment includes: After polishing, single crystal copper was plated in a 50℃, pH=6 bath at 3A / dm 2 Current density electroplating 0.5μm gold layer; 90 parts of polytetrafluoroethylene and 10 parts of nano-silicon dioxide were mixed at 100°C for 15 minutes, extruded through a twin-screw extruder at 360°C and 200 r / min, and coated on the conductor to form an insulating layer; First, a 200-mesh silver-plated copper mesh is coated with 18 spindles and a 60° braid angle. Then, three layers of graphene film are hot-pressed at 220°C and 10 MPa for 5 minutes to form a double-layer shielding layer. 70 parts of polymethylhydrogensiloxane, 30 parts of dimethyl methylphosphonate, 10 parts of nano paraffin and phenyl methyl polysiloxane were dissolved in toluene, stirred at 70°C for 3 hours, coated with 0.3mm and cured at 150°C for 4 hours to form a flame retardant layer; 7% carbon nanotubes and thermoplastic polyurethane were mixed at 1000r / min for 20min, extruded by single screw at 220℃, coated on the surface of flame retardant layer, and water-cooled at 20℃ to obtain flame retardant and fireproof cables suitable for quantum computing equipment.

[0066] Comparative Example 2 The method for preparing a flame-retardant and fire-resistant cable suitable for quantum computing equipment in the embodiment includes: After polishing the single crystal copper conductor, the copper conductor was plated in a 30℃, pH=4 solution at 1A / dm 2 A 0.3 μm nickel layer was electroplated at a current density of 100 nm.

[0067] 95 parts of polytetrafluoroethylene and 5 parts of nano-silicon dioxide were mixed at 80°C for 10 minutes, extruded through a twin-screw extruder at 320°C and 150 r / min, and coated on the conductor to form an insulating layer; A layer of graphene film is hot-pressed at 180°C and 5MPa for 3 minutes to bond to the insulation layer, and then covered with a 200-mesh silver-plated copper mesh with 12 spindles and a 45° braid angle to form a double-layer shielding layer; 60 parts of polymethylhydrogensiloxane, 40 parts of dimethyl methylphosphonate, 5 parts of nano paraffin and polydimethylsiloxane were dissolved in toluene, stirred at 50°C for 2 hours, coated with 0.1mm and cured at 120°C for 2 hours to form a flame retardant layer; 5% carbon nanotubes and thermoplastic polyurethane were mixed at 800r / min for 15min, extruded by a single screw at 180℃ and coated on the surface of the flame retardant layer, and then water-cooled at 10℃ to obtain a flame retardant and fireproof cable suitable for quantum computing equipment.

[0068] Comparative Example 3 The method for preparing a flame-retardant and fire-resistant cable suitable for quantum computing equipment in this embodiment includes: After polishing, single crystal copper was plated in a 40℃, pH=5 bath at 2A / dm 2 The current density was used to electroplate a 0.3 μm palladium layer; 91 parts of polytetrafluoroethylene and 9 parts of nano-silicon dioxide were mixed at 90°C for 12 minutes, extruded through a twin-screw extruder at 340°C and 180 r / min, and coated on the conductor to form an insulating layer; Three layers of graphene film are hot-pressed at 200°C and 8MPa for 4 minutes to form an insulating layer, and then covered with a 150-mesh silver-plated copper mesh with 12 spindles and a 45° braid angle to form a double-layer shielding layer; 64 parts of polymethylhydrogensiloxane, 36 parts of dimethyl methylphosphonate, 9 parts of nano paraffin and polydimethylsiloxane were dissolved in xylene, stirred at 60°C for 2.5 hours, coated with 0.2mm and cured at 130°C for 3 hours to form a flame retardant layer; 6% carbon nanotubes and thermoplastic polyurethane were mixed at 900r / min for 18min, extruded by single screw at 200℃, coated on the surface of flame retardant layer, and water-cooled at 15℃ to obtain flame retardant and fireproof cables suitable for quantum computing equipment.

[0069] Performance Testing 1. Electromagnetic shielding effectiveness (SE) test Purpose: To verify the protection capability of the double-layer shielding structure against quantum signals.

[0070] Method: Use a shielded room and a network analyzer to measure the cable SE value in the 100MHz-10GHz frequency band.

[0071] Standard: GB / T30148-2013 "Measurement method of shielding effectiveness of electromagnetic shielding materials".

[0072] 2. Quantum signal transmission stability test Purpose: To verify the cable's ability to transmit weak quantum signals.

[0073] Method: A quantum signal generator sends a 1 GHz quantum state signal. After transmission through a cable, the received signal is collected by a spectrum analyzer. The spectral characteristics of the received signal are compared with the original transmitted signal, and the signal distortion rate is calculated using Equation 1.

[0074]

[0075] 3. Elongation at break test Purpose: To verify the flexibility of cables at extremely low temperatures.

[0076] Method: The sample was frozen in liquid nitrogen (-196℃) for 2h, stretched at a speed of 50mm / min using a universal material testing machine, and the elongation at break was recorded.

[0077] Standard: GB / T1040.3-2006 "Determination of tensile properties of plastics Part 3: Test conditions for films and sheets".

[0078] 4. Oxygen index test Purpose: To quantify the flame retardancy of cable materials (minimum oxygen concentration required to sustain combustion).

[0079] Method: According to GB / T2406.2-2009 "Determination of combustion behavior of plastics by oxygen index method Part 2: Room temperature test", the cable sample was placed in an oxygen and nitrogen mixed flow, and after ignition, the minimum oxygen volume fraction required to sustain combustion was measured.

[0080] The test results are shown in Table 1.

[0081] Table 1 Performance test results

[0082] Examples 1-8 all achieved SE values ​​≥ 72dB, with Examples 3 / 8, comprising three layers of graphene and a 300-mesh copper mesh, achieving 78dB, demonstrating the synergistic effect of the dual-layer shielding structure. The graphene membranes (layers 1-3) are matched with a 200-300 mesh silver-plated copper mesh. The distortion rate is ≤ 4.5%. High-purity single-crystal copper / silver (≥99.9999%) and gold / palladium coatings (0.1-0.5μm) effectively reduce resistance fluctuations and ensure signal stability. The elongation at break is 320%-380%. The ratio of polytetrafluoroethylene to nanosilicon dioxide (90-95:5-10) ensures the insulation layer resists embrittlement at -196°C. The silicone flame retardant layer synergistically enhances flexibility. The oxygen index is 33%-35%. The silicone-phosphorus flame retardant (60-70:30-40) and nanoparaffin wax (5%-10%) form a dense carbon layer, meeting V-0 flame retardancy requirements.

[0083] In Comparative Example 1, a silver-plated copper mesh was first coated before the graphene film was applied. This resulted in the graphene film being punctured by the copper mesh, resulting in a drop in SE value to 62dB and a surge in quantum signal distortion to 18.2%, demonstrating the critical influence of shielding layer order on quantum signal compatibility. In Comparative Example 2, the nickel plating exhibited a rapid oxidation rate, increasing contact resistance at extremely low temperatures, resulting in a distortion rate of 22.5% and a drop in elongation at break to 185% (due to embrittlement of the nickel plating), demonstrating the necessity of gold / palladium plating for oxidation resistance and low-temperature flexibility. In Comparative Example 3, the weave density was less than 200 mesh, resulting in an excessively large electromagnetic shielding mesh, resulting in an SE value of only 58dB. Signal leakage in the 10GHz band was significant, and mechanical protection was reduced, resulting in a drop in elongation at break to 220%.

Claims

1. A flame retardant and fireproof cable suitable for quantum computing equipment, characterized in that: The flame retardant and fireproof cable comprises, from the inside to the outside, a conductor, an insulating layer wrapped around the outside of the conductor, a shielding layer wrapped around the outside of the insulating layer, a flame retardant layer wrapped around the outside of the shielding layer, and a sheath layer wrapped around the outside of the flame retardant layer; The conductor is made of single crystal copper or single crystal silver, and the surface of the conductor is plated with a gold layer or a palladium layer; The insulating layer is composed of polytetrafluoroethylene and nano-silicon dioxide; The shielding layer includes: a graphene film coated on the outside of the insulating layer and a silver-plated copper mesh coated on the outside of the graphene film; The flame retardant layer is composed of an organic silicon flame retardant, a phosphorus flame retardant, nano paraffin and a polymer matrix material; The sheath layer consists of thermoplastic polyurethane and carbon nanotubes.

2. The flame-retardant and fire-resistant cable suitable for quantum computing equipment according to claim 1, characterized in that: The purity of the single crystal copper or single crystal silver is not less than 99.9999%, and the thickness of the gold layer or palladium layer is 0.1-0.5 μm.

3. The flame-retardant and fire-proof cable suitable for quantum computing equipment according to claim 2, characterized in that: The number of layers of the graphene film is 1-3, and the film thickness does not exceed 1nm; the weaving density of the silver-plated copper mesh is 200-300 meshes, and the thickness of the silver-plated layer is 1-3μm.

4. The flame-retardant and fire-resistant cable suitable for quantum computing equipment according to claim 1, characterized in that: The mass ratio of the organic silicon flame retardant to the phosphorus flame retardant is (60-70): (30-40); the added amount of the nano paraffin is 5%-10% of the total mass of the flame retardant layer raw materials.

5. The flame-retardant and fire-proof cable suitable for quantum computing equipment according to claim 4, characterized in that: The polymer matrix material includes one or more of polydimethylsiloxane, vinyl-terminated polydimethylsiloxane, phenylmethylpolysiloxane, hydroxyl-terminated polydimethylsiloxane or amino-modified polysiloxane.

6. The flame-retardant and fire-resistant cable suitable for quantum computing equipment according to claim 1, characterized in that: The mass ratio of the polytetrafluoroethylene to the nano-silicon dioxide is (90-95): (5-10).

7. The flame-retardant and fire-resistant cable suitable for quantum computing equipment according to claim 1, characterized in that: The added amount of the carbon nanotubes is 5%-8% of the mass of the thermoplastic polyurethane.

8. A method for preparing a flame-retardant and fire-resistant cable suitable for quantum computing equipment according to any one of claims 1 to 7, characterized in that The following steps are involved: The surface of single crystal copper or single crystal silver is polished and then plated with a gold layer or a palladium layer to obtain a conductor; Polytetrafluoroethylene and nano-silicon dioxide are mixed evenly and then melted and extruded to obtain an insulating material; the insulating material is evenly coated on the surface of the conductor to form an insulating layer; After laminating the graphene film on the surface of the insulating layer, a silver-plated copper mesh is coated on the surface of the graphene film to form a double-layer shielding layer; The organic silicon flame retardant, phosphorus flame retardant, nano paraffin, polymer matrix material and organic solvent are uniformly mixed to obtain a flame retardant solution; the flame retardant solution is coated on the surface of the shielding layer, and the flame retardant layer is formed after drying and curing; The carbon nanotubes and thermoplastic polyurethane are evenly mixed and then extruded to obtain a sheath material; the sheath material is coated on the surface of the flame retardant layer and cooled and shaped to obtain a flame retardant and fireproof cable suitable for quantum computing equipment.

9. The preparation method according to claim 8, wherein The step of laminating the graphene film to the surface of the insulating layer comprises: The graphene film is bonded to the surface of the insulating layer using a hot pressing process with a hot pressing temperature of 180-220°C, a pressure of 5-10 MPa, and a holding time of 3-5 minutes. The process of coating the silver-plated copper mesh on the surface of the graphene film includes coating the silver-plated copper mesh on the outer layer of the graphene film in a weaving manner of 12-18 spindles using a weaving machine, and controlling the weaving angle at 45-60 degrees.

10. The preparation method according to claim 8, characterized in that The step of coating the flame retardant solution on the surface of the shielding layer and drying and curing the flame retardant layer comprises: The flame retardant solution is coated on the surface of the shielding layer, and the coating thickness is controlled at 0.1-0.3 mm; after coating, it is placed in an oven at 120-150° C. for drying and curing for 2-4 hours to form a flame retardant layer.

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