Low-evaporation rubber hose for liquid cooling system and method for manufacturing the same

Abstract

The application discloses a low-evaporation rubber hose for a liquid cooling system, which comprises, from inside to outside, an inner rubber layer, a middle rubber layer, a reinforcing layer and an outer rubber layer; the rubber material of the inner rubber layer is a ternary ethylene-propylene rubber material which has bonding properties with the rubber material of the middle rubber layer; the rubber material of the middle rubber layer is a brominated butyl rubber material which has adhesion with the rubber material of the inner rubber layer; the reinforcing layer is woven by polyester fibers; and the rubber material of the outer rubber layer is a flame-retardant ternary ethylene-propylene rubber material. The rubber hose has the advantages of high flame retardance, excellent medium resistance and compatibility, softness, easy bending, long service life and the like, is suitable for the liquid cooling system and can ensure long-term, safe and reliable operation of the liquid cooling system.

Description

Technical Field

[0001] This invention belongs to the field of rubber composite materials, and relates to a rubber compound for preparing rubber hoses for liquid cooling systems, a low-evaporation rubber hose for liquid cooling systems, and a method for preparing the same. Background Technology

[0002] With the rapid development of mobile internet, cloud computing, and big data, the amount of data generated by economic and social operations will expand rapidly. This massive data throughput and computation presents unprecedented energy consumption and heat dissipation challenges for data centers, which serve as the "brains" of emerging technologies such as artificial intelligence and big data. Against this backdrop, liquid-cooled data centers, utilizing liquid cooling technology and liquid-cooled servers, have emerged, providing a new solution for data center cooling.

[0003] Liquid cooling technology, as a relatively mature cooling technology, is currently widely used in aerospace, automotive, and other fields. Ethylene glycol aqueous solutions are the "economic first choice" for liquid cooling systems, especially suitable for medium-temperature, medium-power-density scenarios where environmental sensitivity is not a concern. Cooling hoses, as key components of liquid cooling systems, play a flexible connection role in data center systems and need to meet various performance requirements, among which water permeability is a key performance indicator.

[0004] In existing technologies, metal cooling pipes made of materials such as copper and aluminum, while exhibiting excellent thermal conductivity, suffer from inherent defects such as poor toughness and large bending radii. These limitations restrict the flexibility of cooling pipe layout and, due to significant thermal expansion and contraction, easily lead to stress concentration, deformation, and even leakage, thus shortening the service life of the cooling pipes and affecting the overall system performance. While PTFE (polytetrafluoroethylene) pipes offer advantages such as high temperature resistance, corrosion resistance, and good insulation, they also have some significant drawbacks. For example, under continuous load or high temperature, PTFE undergoes slow deformation (creep), which may lead to pipe loosening, seal failure, or even coolant leakage. Furthermore, its high rigidity and large bending radius make it difficult to adapt to complex piping layouts. Traditional EPDM hoses, while possessing high and low temperature resistance, good flexibility, and low cost, suffer from insufficient water permeability at high temperatures to meet low evaporation requirements. Therefore, developing a low-evaporation rubber hose for liquid cooling systems has become an urgent technical challenge. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing cooling pipes in liquid cooling systems. Taking into account factors such as flexibility, bending performance, and permeability, this invention innovates the rubber materials and structure of the hose to provide a low-evaporation rubber hose for cold plate cooling systems. This hose not only has excellent flexibility and a small bending radius, but also excellent resistance to permeation of ethylene glycol aqueous solutions, and has a long service life, ensuring the long-term, safe, and reliable operation of the liquid cooling system.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] A rubber compound for preparing low-evaporation rubber hoses for liquid cooling systems includes an EPDM rubber compound for preparing the inner rubber layer and a brominated butyl rubber compound for preparing the middle rubber layer.

[0008] The EPDM rubber compound used to prepare the inner rubber layer is made from the following raw materials in parts by weight: 100 parts EPDM rubber, 30-50 parts carbon black, 30-50 parts talc, 15-25 parts liquid EPDM rubber, 2-4 parts vulcanizing agent, and 1-3 parts crosslinking agent.

[0009] The EPDM rubber has a Mooney viscosity ML(1+4) of 60-70 at 125°C, an ethylene content of 60-70%, and a third monomer ENB content of 4-6%.

[0010] Specifically, the EPDM rubber mentioned can be Keltan 6470C.

[0011] The carbon black is one or more of N550 carbon black, N660 carbon black and N774 carbon black, preferably a combination of N550 carbon black and N774 carbon black in a weight ratio of 3:1.

[0012] The liquid ethylene propylene rubber has a Mooney viscosity ML(1+4) of 5 to 15 at 100°C and an ethylene content of 45 to 55%.

[0013] Specifically, the liquid ethylene propylene rubber can be selected from J-0010 binary ethylene propylene rubber.

[0014] The vulcanizing agent is 4,4-di(tert-butylperoxy)valerate n-butyl ester.

[0015] The crosslinking agent is a combination of at least one selected from TAIC and TMPTMA and HVA-2 (i.e., N,N-m-phenylenebismaleimide), preferably a combination of TAIC and HVA-2 with a weight ratio of 1.5:1 to 2.5:1, and more preferably a combination of TAIC and HVA-2 with a weight ratio of 2:1.

[0016] The brominated butyl rubber compound used in the preparation of the adhesive layer is made from the following raw materials in parts by weight: 100 parts brominated butyl rubber, 50-70 parts N550 carbon black, 20-40 parts inorganic filler, 10-15 parts paraffin oil, 3-6 parts adhesive resin, 3-5 parts vulcanizing agent, and 2-4 parts crosslinking agent.

[0017] The brominated butyl rubber has a Mooney viscosity (ML(1+4)) of 35–55 at 125°C and a bromine content of 1.5–2.0%.

[0018] Specifically, the brominated butyl rubber can be CENWAY BIIR-2502.

[0019] The inorganic filler is one or more of talc, montmorillonite, and kaolin, preferably a combination of talc and montmorillonite in a weight ratio of 1:1.

[0020] The paraffin oil mentioned is paraffin oil 2280.

[0021] The adhesive resin is a combination of modified phenolic resin SL-3025C and rubber adhesive RA-65 in a weight ratio of 1:1.5 to 1:2.5, preferably a combination of modified phenolic resin SL-3025C and rubber adhesive RA-65 in a weight ratio of 1:2.

[0022] The vulcanizing agent is 4,4-di(tert-butylperoxy)valerate n-butyl ester.

[0023] The crosslinking agent is a combination of crosslinking agent HVA-2, zinc oxide and stearic acid in a weight ratio of (1.0-1.5):(0.2-0.5):1.

[0024] The EPDM rubber compound used to prepare the inner rubber layer and the brominated butyl rubber compound used to prepare the middle rubber layer exhibit significant bonding properties.

[0025] Another object of the present invention is to provide a low-evaporation rubber hose for a liquid cooling system, wherein the rubber hose comprises, from the inside out, an inner rubber layer, a middle rubber layer, a reinforcing layer, and an outer rubber layer; the rubber compound of the inner rubber layer is an EPDM rubber compound that has adhesive properties with the rubber compound of the middle rubber layer; the rubber compound of the middle rubber layer is a brominated butyl rubber compound that has adhesive properties with the rubber compound of the inner rubber layer; the reinforcing layer is woven from polyester fibers; and the rubber compound of the outer rubber layer is a flame-retardant EPDM rubber compound.

[0026] The thickness of the inner adhesive layer is 0.5–1.0 mm; the thickness of the middle adhesive layer is 0.5–1.5 mm; and the thickness of the outer adhesive layer is 1.0–1.5 mm.

[0027] The polyester fiber is 1000D to 3000D polyester yarn, specifically 2000D polyester yarn; the weaving method is a 24-spindle * 2-strand weaving method.

[0028] The braided coverage of the reinforcing layer is 60% to 70%.

[0029] The flame-retardant EPDM rubber compound is made from the following raw materials in parts by weight: 100 parts EPDM rubber, 5 parts zinc oxide, 1 part stearic acid, 25-45 parts N550 carbon black, 10-20 parts kaolin, 70-100 parts flame retardant, 2-5 parts silane coupling agent, 25-35 parts paraffin oil, 5-10 parts binder, 0.5-1.5 parts sulfur, and 4-7 parts accelerator.

[0030] The EPDM rubber has a Mooney viscosity ML(1+4) of 20-30 at 100°C, an ethylene content of 65-75%, and a third monomer ENB content of 4-6%.

[0031] The EPDM rubber mentioned can be Keltan 2470C.

[0032] The flame retardant is a combination of aluminum hydroxide, zinc borate, antimony trioxide and nitrogen-phosphorus compound flame retardant Longsafe201 in a weight ratio of 1:(0.2~0.4):(0.1~0.2):(0.3~0.5).

[0033] Preferably, the flame retardant is a combination of aluminum hydroxide, zinc borate, antimony trioxide and nitrogen-phosphorus compound flame retardant Longsafe 201 in a weight ratio of 1:0.25:(0.12~0.14):(0.4~0.45).

[0034] The silane coupling agent mentioned is silane coupling agent Si-69.

[0035] The paraffin oil mentioned is paraffin oil 2280.

[0036] The adhesive is a combination of adhesive SL-3025C and adhesive RA-65 in a weight ratio of 1:1.5.

[0037] The accelerator is one or more of accelerator TMTD, accelerator BZ, accelerator CZ, and accelerator ZBEC, preferably a combination of accelerator TMTD, accelerator BZ, accelerator CZ and accelerator ZBEC in a weight ratio of 1:1:1.5:0.5.

[0038] Another object of the present invention is to provide a method for preparing a low-evaporation rubber hose for a liquid cooling system, comprising the following steps:

[0039] Step a: Set the temperatures of each zone of the composite rubber extruder to 60±5℃, 70±5℃, 75±5℃, and 80±5℃ respectively. Feed the inner rubber layer and the middle rubber layer into the feed port of the rubber composite extruder respectively. Insert the mandrel into the rubber composite extruder. The plasticized inner rubber layer and the middle rubber layer enter the co-extrusion die and are compounded under vacuum to obtain a tube blank composed of an inner rubber layer and a middle rubber layer.

[0040] Step b: The tube blank with the mandrel is threaded into the braiding machine to braid the fibers and obtain a tube blank containing a reinforcing layer;

[0041] Step c: Set the temperatures of each zone of the rubber extruder to 60±5℃, 70±5℃, 75±5℃, and 80±5℃ respectively. Feed the rubber compound of the outer rubber layer into the feed port of the rubber extruder. Insert the tube blank with the mandrel and the reinforcing layer into the rubber extruder and extrude the outer rubber layer under vacuum conditions to obtain the final tube blank.

[0042] Step d: After wrapping the final pipe blank with TPX, high-temperature vulcanization is carried out;

[0043] Step e: After vulcanization, the TPX is removed from the hose and the core is removed to obtain a rubber hose.

[0044] In step d, the vulcanization temperature is 160±2℃, the vulcanization pressure is 0.56±0.05MPa, and the vulcanization time is 60±0.5min.

[0045] The beneficial effects of this invention are:

[0046] The hose of this invention has advantages such as high flame retardancy, excellent media compatibility, flexibility, and long service life. It is suitable for liquid cooling systems and can ensure the long-term, safe, and reliable operation of the liquid cooling system. Specifically, it is characterized by:

[0047] This invention incorporates N,N-m-phenylenebismaleimide into the rubber compounds of the inner and middle layers. On one hand, the maleic anhydride groups can chemically react with the oxygen-containing groups on the surface of inorganic fillers, reducing the surface energy of the filler particles, increasing the dispersibility of the fillers, and effectively improving their interfacial bonding with the rubber matrix. On the other hand, in the peroxide vulcanization system, N,N-m-phenylenebismaleimide can introduce heat-resistant groups such as imide heterocycles and benzene rings into the crosslinking network structure of the rubber compound, improving the high-temperature resistance of the rubber. At the same time, N,N-m-phenylenebismaleimide can also improve the co-vulcanization of the inner and middle layers, enabling the inner and middle layers to form a stronger crosslinking network, enhancing the adhesion between them, and preventing delamination, bubbling, and media migration problems.

[0048] The low molecular weight segments of liquid ethylene propylene rubber (EPR) act as "molecular chain lubricants," reducing friction between the EPR macromolecular chains and minimizing stress concentration during bending, thus improving the hose's flexibility and fatigue resistance. Liquid EPR can also be uniformly distributed within the EPR macromolecular chains in the compound, forming a "micro-crosslinking network" that hinders the diffusion of ethylene glycol aqueous solution molecules, extending the corrosion failure cycle, improving the hose's resistance to media corrosion, and ensuring its long-term stability in ethylene glycol aqueous solution environments.

[0049] The saturated polyisobutylene structure in the molecule of brominated butyl rubber endows it with high barrier properties against air and water vapor. By adding inorganic fillers such as talc and montmorillonite, on the one hand, montmorillonite can act as a physical cross-linking point in the rubber and can generate a strong binding force with brominated butyl rubber, which is conducive to increasing the cross-linking density of the rubber material, forming a stable network structure, increasing the structural compactness, and increasing the difficulty for gas / liquid to enter and exit the rubber network. At the same time, due to the lamellar structure of talc and montmorillonite, the permeation path of gas or liquid molecules entering and exiting the rubber material can be extended. Both of these effects endow the rubber material with low permeability.

[0050] In addition, the hose adopts an EPDM / IIR composite structure, which not only avoids the problem of pure butyl rubber hardening and rapid elasticity decay due to long-term contact with coolant; but also forms a double barrier, reducing the permeation and precipitation of trace coolant molecules into the pipe wall, reducing evaporation loss, and effectively preventing air from seeping into the pipe, reducing the oxidation and acidification of ethylene glycol coolant, extending the coolant replacement cycle, and significantly reducing the cost of manual maintenance and consumable replacement. Attached Figure Description

[0051] Figure 1 This is a schematic diagram of the structure of the rubber hose used in the liquid cooling system of the present invention.

[0052] Figure 1 In the middle, 1-inner adhesive layer, 2-middle adhesive layer, 3-reinforcing layer, 4-outer adhesive layer. Detailed Implementation

[0053] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0054] As shown in Table 1, taking the low-evaporation rubber hose of the cold plate liquid cooling system with a diameter of Φ16.0±0.4mm×22.0±0.5mm as an example, the structure of the hose is as follows: from the inside to the outside.

[0055] Table 1. Hose Structure

[0056]

[0057] Example 1

[0058] The EPDM rubber compound, which has good adhesion to the middle rubber layer, is used to prepare the inner layer of low-evaporation rubber hoses for cold-plate liquid cooling systems. It is made from the following raw materials in parts by weight: 100 parts EPDM Keltan 6470C, 30 parts N550 carbon black, 10 parts N774 carbon black, 40 parts talc, 20 parts liquid EPDM J-0010, 3 parts 4,4-di(tert-butylperoxy)valerate n-butyl ester, 1.5 parts co-crosslinking agent TAIC, and 0.75 parts co-crosslinking agent HVA-2.

[0059] The preparation method of the EPDM rubber compound in this embodiment is as follows:

[0060] Step (1): Cool the internal mixer with water and control the temperature of the internal mixer chamber to not exceed 60°C. Add EPDM Keltan 6470C (base material), liquid EPDM J-0010 and talc powder, and mix for 120 seconds.

[0061] Step (2): Add N550 carbon black and N774 carbon black, and mix for 6 minutes;

[0062] Step (3): Add 4,4-di(tert-butyl peroxy)valerate and crosslinking agent TAIC and HVA-2, mix, and discharge the rubber compound after the temperature reaches 120℃;

[0063] Step (4): Transfer the rubber compound to the open mill, pass it through the thin mill, and cool it to room temperature to obtain EPDM rubber material, which is the inner rubber layer.

[0064] Example 2

[0065] A brominated butyl rubber compound with good adhesion to the inner rubber layer is used to prepare the middle layer of a low-evaporation rubber hose for a cold plate liquid cooling system. It is made from the following raw materials in parts by weight: 100 parts brominated butyl rubber CENWAYBIIR-2502, 60 parts N550 carbon black, 15 parts talc, 15 parts montmorillonite, 10 parts paraffin oil 2280, 1.5 parts modified phenolic resin SL-3025C, 3 parts adhesive resin RA-65, 4 parts 4,4-di(tert-butylperoxy)valerate n-butyl ester, 1 part co-crosslinking agent HVA-2, 0.5 parts zinc oxide, and 1 part stearic acid.

[0066] The preparation method of brominated butyl rubber compound in this embodiment includes the following steps:

[0067] Step (1): Cool the internal mixer with water and control the temperature of the internal mixer chamber to not exceed 60°C. Add brominated butyl rubber CENWAY BIIR-2502 (base material), talc and montmorillonite, and mix for 120 seconds.

[0068] Step (2): Add N550 carbon black and paraffin oil 2280, mix, and discharge the rubber compound after the temperature reaches 130℃.

[0069] Step (3): Transfer the rubber compound to the open mill, sheet it out in thin sheets, cool it to room temperature to obtain brominated butyl masterbatch, and let it stand for 12 hours;

[0070] Step (4): Cool the internal mixer with water and control the temperature of the internal mixer chamber to not exceed 60°C. Add brominated butyl masterbatch and mix for 60 seconds.

[0071] Step (5): Add 4,4-di(tert-butyl peroxy)valerate, crosslinking agent HVA-2, modified phenolic resin SL-3025C, adhesive resin RA-65, zinc oxide and stearic acid, mix, and discharge the rubber compound after the temperature reaches 85℃.

[0072] Step (6): Transfer the rubber compound to the open mill, pass it through the thin mill, and cool it to room temperature to obtain brominated butyl rubber material, which is the rubber compound of the middle layer.

[0073] Example 3

[0074] The flame-retardant EPDM rubber compound used to prepare the outer layer of low-evaporation rubber hoses for cold-plate liquid cooling systems is made from the following raw materials in parts by weight: 100 parts EPDM rubber Keltan 2470C, 5 parts zinc oxide, 1 part stearic acid, 40 parts N550 carbon black, 15 parts kaolin, 60 parts aluminum hydroxide, 15 parts zinc borate, 8 parts antimony trioxide, 25 parts phosphorus-nitrogen compound flame retardant Longsafe 201, 3 parts silane coupling agent Si-69, 30 parts paraffin oil 2280, 2 parts modified phenolic resin SL-3025C, 3 parts adhesive resin RA-65, 0.5 parts sulfur, 1 part accelerator TMTD, 1 part accelerator BZ, 1.5 parts accelerator CZ, and 0.5 parts accelerator ZBEC.

[0075] The preparation method of flame-retardant EPDM rubber compound in this embodiment includes the following steps:

[0076] Step (1): Cool the internal mixer with water and control the temperature of the internal mixer chamber to not exceed 60°C. Add EPDM rubber Keltan 2470C (base material), kaolin, zinc oxide and stearic acid, and mix for 120 seconds.

[0077] Step (2): Add aluminum hydroxide, zinc borate, antimony trioxide, phosphorus-nitrogen compound flame retardant Longsafe 201 and silane coupling agent Si-69, and mix for 2 minutes;

[0078] Step (3): Add N550 carbon black and paraffin oil 2280, mix, and after the temperature reaches 140℃, discharge the EPDM masterbatch and let it stand for 12 hours.

[0079] Step (4): Cool the internal mixer with water and control the temperature of the internal mixer chamber to not exceed 60°C. Add EPDM masterbatch and mix for 60 seconds.

[0080] Step (5): Add modified phenolic resin SL-3025C, adhesive resin RA-65, sulfur, accelerator TMTD, accelerator BZ, accelerator CZ and accelerator ZBEC, mix, and discharge the rubber compound after the temperature reaches 100℃.

[0081] Step (6): Transfer the rubber compound to the open mill, pass it through the thin mill, and cool it to room temperature to obtain flame-retardant EPDM rubber material, which is the outer rubber layer.

[0082] Example 4

[0083] like Figure 1 As shown, a low-evaporation rubber hose for a liquid cooling system comprises, from the inside out: an inner rubber layer 1, a middle rubber layer 2, a reinforcing layer 3, and an outer rubber layer 4; the rubber compound of the inner rubber layer 1 is EPDM rubber compound of Example 1; the rubber compound of the middle rubber layer 2 is butyl bromide rubber compound of Example 2; and the rubber compound of the outer rubber layer 4 is flame-retardant EPDM rubber compound of Example 3.

[0084] The preparation method of the low-evaporation rubber hose for the liquid cooling system is as follows:

[0085] Step a: Set the temperatures of each zone of the composite rubber extruder to 60±5℃, 70±5℃, 75±5℃, and 80±5℃ respectively. Feed the inner rubber layer and the middle rubber layer into the feed port of the rubber composite extruder respectively. Insert the φ15.8mm mandrel into the rubber composite extruder. The plasticized inner rubber layer and the middle rubber layer enter the co-extrusion die. Under vacuum conditions (vacuum degree ≤40 KPa), composite extrusion is performed to obtain a tube blank composed of an inner rubber layer and a middle rubber layer.

[0086] Step b: The tube blank with the mandrel is fed into the braiding machine. 2000D polyester yarn is used and braided in a 24-spindle * 2-strand braiding method. The coverage of the reinforcing layer is 65%, and a tube blank containing the reinforcing layer is obtained.

[0087] Step c: Set the temperatures of each zone of the rubber extruder to 60±5℃, 70±5℃, 75±5℃, and 80±5℃ respectively. Feed the rubber compound of the outer rubber layer into the feed port of the rubber extruder. Insert the tube blank with the mandrel and the reinforcing layer into the rubber extruder. Extrude the outer rubber layer under vacuum conditions (vacuum degree ≤40 KPa) to obtain the final tube blank.

[0088] Step d: Coat the end tube blank with TPX; transfer the TPX-coated end tube blank to a high-temperature steam vulcanization chamber and vulcanize for 60 min ± 5 min at a temperature of 160℃ ± 2℃ and a pressure of 0.60 ± 0.05 MPa.

[0089] Step e: The vulcanized product is then subjected to TPX stripping and core removal to obtain a low-evaporation rubber hose for liquid cooling systems.

[0090] Example 5

[0091] The structure and preparation method of the rubber hose in this embodiment are the same as those in Embodiment 4, except that the thickness of the middle rubber layer of the rubber hose is adjusted to 1.50 mm.

[0092] Comparative Example 1

[0093] Existing conventional EPDM rubber hoses for liquid cooling systems: Compared to Example 4, they do not contain a middle rubber layer, and the thickness of the inner rubber layer is adjusted to 1.50 mm; otherwise, they are the same as Example 4.

[0094] Comparative Example 2

[0095] Compared with Example 4, this example does not include a middle adhesive layer, uses the same adhesive material as Example 2 for the inner adhesive layer, and adjusts the thickness of the inner adhesive layer to 1.50 mm. The rest is the same as Example 4.

[0096] The performance of the rubber hoses of Examples 4-5 and Comparative Examples 1-2 is shown in Table 2.

[0097] Table 2. Performance of Rubber Hose

[0098]

[0099] Note: The absence of a year after the standard number indicates the latest version is used; the test media used for pulse, permeability, and compatibility tests are all ethylene glycol aqueous solutions (ethylene glycol:water volume ratio = 25:75).

[0100] The results are shown in Table 2. Compared with the existing ordinary EPDM rubber hoses used in liquid cooling systems (Comparative Example 1), the low-evaporation rubber hose of the present invention, while meeting the performance requirements of burst and pulse, fully inherits the flexibility of ordinary EPDM rubber hoses and adds the key function of low permeability, thus achieving higher safety.

[0101] Comparative Example 2: The inner layer of the rubber hose is made of brominated butyl rubber compound with a peroxide vulcanization system. After a compatibility test between the compound and ethylene glycol aqueous solution, turbidity appeared, which would contaminate the liquid cooling system and reduce its service life.

[0102] In summary, the low-evaporation rubber hose for liquid cooling systems of the present invention has the characteristics of excellent media compatibility, flexibility and bendability, and long service life.

Claims

1. A rubber compound for preparing low-evaporation rubber hoses for liquid cooling systems, characterized in that: This includes EPDM rubber compounds for preparing the inner rubber layer and brominated butyl rubber compounds for preparing the middle rubber layer; The EPDM rubber compound is made from the following raw materials in parts by weight: 100 parts EPDM rubber, 30-50 parts carbon black, 30-50 parts talc, 15-25 parts liquid EPDM rubber, 2-4 parts vulcanizing agent, and 1-3 parts co-crosslinking agent; wherein the EPDM rubber has a Mooney viscosity ML(1+4) of 60-70 at 125°C, an ethylene content of 60-70%, and a third monomer ENB content of 4-6%; the liquid EPDM rubber has a Mooney viscosity ML(1+4) of 5-15 at 100°C and an ethylene content of 45-55%; the co-crosslinking agent is a combination of at least one selected from TAIC and TMPTMA and HVA-2; The brominated butyl rubber compound is made from the following raw materials in parts by weight: 100 parts brominated butyl rubber, 50-70 parts N550 carbon black, 20-40 parts inorganic filler, 10-15 parts paraffin oil, 3-6 parts adhesive resin, 3-5 parts vulcanizing agent, and 2-4 parts co-crosslinking agent; wherein the Mooney viscosity ML(1+4) at 125°C of the brominated butyl rubber is 35-55, and the bromine content is 1.5-2.0%; the co-crosslinking agent is a combination of co-crosslinking agent HVA-2, zinc oxide, and stearic acid in a weight ratio of (1.0-1.5):(0.2-0.5):

1.

2. The rubber compound for preparing low-evaporation rubber hoses for liquid cooling systems according to claim 1, characterized in that: In the EPDM rubber compound, the carbon black is one or more of N550 carbon black, N660 carbon black and N774 carbon black; the vulcanizing agent is n-butyl 4,4-di(tert-butyl peroxy)valerate; and the co-crosslinking agent is a combination of TAIC and HVA-2 in a weight ratio of 1.5:1 to 2.5:

1.

3. The rubber compound for preparing low-evaporation rubber hoses for liquid cooling systems according to claim 2, characterized in that: In the EPDM rubber compound, the carbon black is a combination of N550 carbon black and N774 carbon black in a weight ratio of 3:1; the crosslinking agent is a combination of TAIC and HVA-2 in a weight ratio of 2:

1.

4. The rubber compound for preparing low-evaporation rubber hoses for liquid cooling systems according to claim 1, characterized in that: In the brominated butyl rubber compound, the inorganic filler is one or more of talc, montmorillonite, and kaolin; the paraffin oil is paraffin oil 2280; the adhesive resin is a combination of modified phenolic resin SL-3025C and rubber adhesive RA-65 in a weight ratio of 1:1:1.5 to 1:2.5; and the vulcanizing agent is 4,4-di(tert-butylperoxy)valerate n-butyl ester.

5. The rubber compound for preparing low-evaporation rubber hoses for liquid cooling systems according to claim 4, characterized in that: In the brominated butyl rubber compound, the inorganic filler is a combination of talc and montmorillonite in a weight ratio of 1:1, and the adhesive resin is a combination of modified phenolic resin SL-3025C and rubber adhesive RA-65 in a weight ratio of 1:

2.

6. A low-evaporation rubber hose for a liquid cooling system, characterized in that: The rubber hose comprises, from the inside out, an inner rubber layer, a middle rubber layer, a reinforcing layer, and an outer rubber layer; the rubber compound of the inner rubber layer is the EPDM rubber compound as described in claim 1; the rubber compound of the middle rubber layer is the brominated butyl rubber compound as described in claim 1; the reinforcing layer is woven from polyester fibers; and the rubber compound of the outer rubber layer is a flame-retardant EPDM rubber compound.

7. The low-evaporation rubber hose for a liquid cooling system according to claim 6, characterized in that: The thickness of the inner adhesive layer is 0.5–1.0 mm; the thickness of the middle adhesive layer is 0.5–1.5 mm; the thickness of the outer adhesive layer is 1.0–1.5 mm; the polyester fiber is 1000D–3000D polyester yarn, preferably 2000D polyester yarn; the weaving method is a 24-spindle * 2-strand weaving method; the weaving coverage of the reinforcing layer is 60%–70%.

8. The low-evaporation rubber hose for a liquid cooling system according to claim 6, characterized in that: The flame-retardant EPDM rubber compound is made from the following raw materials in parts by weight: 100 parts EPDM rubber, 5 parts zinc oxide, 1 part stearic acid, 25-45 parts N550 carbon black, 10-20 parts kaolin, 70-100 parts flame retardant, 2-5 parts silane coupling agent, 25-35 parts paraffin oil, 5-10 parts binder, 0.5-1.5 parts sulfur, and 4-7 parts accelerator; wherein the Mooney viscosity ML(1+4) of the EPDM rubber at 100°C is 20-30, the ethylene content is 65-75%, and the content of the third monomer ENB is 4-6%; the flame retardant is a compound flame retardant of aluminum hydroxide, zinc borate, antimony trioxide, and nitrogen-phosphorus Longsafe. 201 is a combination of silane coupling agent Si-69 and paraffin oil 2280 in a weight ratio of 1:(0.2~0.4):(0.1~0.2):(0.3~0.5), wherein the silane coupling agent is silane coupling agent Si-69, the paraffin oil is paraffin oil 2280, the adhesive is adhesive SL-3025C and adhesive RA-65 in a weight ratio of 1:1.5, and the accelerator is one or more of accelerator TMTD, accelerator BZ, accelerator CZ and accelerator ZBEC, preferably a combination of accelerator TMTD, accelerator BZ, accelerator CZ and accelerator ZBEC in a weight ratio of 1:1:1.5:0.

5.

9. A method for preparing a low-evaporation rubber hose for a liquid cooling system as described in claim 6, characterized in that: Includes the following steps: Step a: Set the temperatures of each zone of the composite rubber extruder to 60±5℃, 70±5℃, 75±5℃, and 80±5℃ respectively. Feed the inner rubber layer and the middle rubber layer into the feed port of the rubber composite extruder respectively. Insert the mandrel into the rubber composite extruder. The plasticized inner rubber layer and the middle rubber layer enter the co-extrusion die and are compounded under vacuum to obtain a tube blank composed of an inner rubber layer and a middle rubber layer. Step b: The tube blank with the mandrel is threaded into the braiding machine to braid the fibers and obtain a tube blank containing a reinforcing layer; Step c: Set the temperatures of each zone of the rubber extruder to 60±5℃, 70±5℃, 75±5℃, and 80±5℃ respectively. Feed the rubber compound of the outer rubber layer into the feed port of the rubber extruder. Insert the tube blank with the mandrel and the reinforcing layer into the rubber extruder and extrude the outer rubber layer under vacuum conditions to obtain the final tube blank. Step d: After wrapping the final pipe blank with TPX, high-temperature vulcanization is carried out; Step e: After vulcanization, the TPX is removed from the hose and the core is removed to obtain a rubber hose.

10. The method for preparing a low-evaporation rubber hose for a liquid cooling system according to claim 9, characterized in that: In step d, the vulcanization temperature is 160±2℃, the vulcanization pressure is 0.56±0.05MPa, and the vulcanization time is 60±0.5min.

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