High-thermal-conductivity ethylene propylene diene monomer sealing material and preparation method thereof
By using modified copper powder and zinc oxide-coated aluminum nitride and pre-mixing technology, the thermal conductivity and insulation problems of EPDM rubber sealing materials are solved, the thermal conductivity and insulation properties of the sealing materials are improved, and the service life is extended.
Patent Information
- Application Number
- CN202511218045.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-28
- Publication Date
- 2025-10-17
AI Technical Summary
Existing EPDM rubber sealing materials are difficult to achieve both high thermal conductivity and insulation performance, resulting in a reduced service life of the sealing ring.
Modified copper powder and zinc oxide-coated aluminum nitride are used as thermal conductive fillers, combined with acrylonitrile-grafted EPDM rubber. The interface bonding between copper powder and rubber is improved through modification treatment, and the thermal conductive filler is pre-mixed during the mixing process to form a continuous low thermal resistance thermal conductive network.
The high thermal conductivity (thermal conductivity ≥ 2.1 W/(m·K)-1) and insulation performance (volume resistivity of 1014Ω·cm) of the sealing material are achieved, while the tensile strength and toughness of the material are improved.
Smart Images
Figure BDA0005570761860000121
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of sealing materials, and particularly relates to a high-thermal-conductivity ethylene-propylene-diene rubber sealing material and a preparation method thereof. BACKGROUND
[0002] Gas insulated switchgear (GIS) is widely used in the field of electrical equipment due to its high reliability, small maintenance amount, excellent insulation performance and other advantages. Most GIS devices use SF6 gas as an insulating medium, and a rubber sealing ring needs to be installed to ensure its sealing performance. Ethylene-propylene-diene rubber (EPDM) is often used as the preferred rubber material for GIS sealing rings due to its excellent weather resistance, ozone resistance, water resistance, good chemical resistance, high and low temperature resistance, electrical insulation and resilience.
[0003] However, in actual use, ethylene-propylene-diene rubber is a poor thermal conductor, which can easily accelerate aging due to heat accumulation, resulting in a reduced service life of the rubber sealing ring. Therefore, in order to improve the heat resistance of ethylene-propylene-diene rubber sealing materials, a thermal conductive material is often filled in the rubber system to improve the heat resistance of the rubber product, accelerate the heat conduction of the rubber and its contact components, reduce the heat accumulation of the rubber product, and reduce the actual use temperature of the rubber to improve the heat resistance and aging resistance of the rubber product.
[0004] Commonly used thermal conductive materials include metal powders such as aluminum, copper and silver, and carbon-based materials such as graphene, carbon fiber and carbon nanotube. Among them, metal powders have high thermal conductivity, but have large density and poor interface bonding with rubber. Graphene and other carbon-based materials have excellent thermal conductivity, but are expensive and prone to aggregation. In addition, metal powders and carbon-based materials have good electrical conductivity, and high filling amount can cause the insulation performance of the rubber product to decrease. Therefore, it is an urgent technical problem to provide an insulating and high-thermal-conductivity ethylene-propylene-diene rubber sealing material. SUMMARY
[0005] The purpose of the present application is to provide a high-thermal-conductivity ethylene-propylene-diene rubber sealing material and a preparation method thereof, to solve the problem that the ethylene-propylene-diene rubber sealing material in the prior art cannot have high thermal conductivity and insulation.
[0006] The purpose of the present application can be achieved by the following technical solutions:
[0007] A high-thermal-conductivity ethylene-propylene-diene rubber sealing material comprises the following raw materials by weight:
[0008] The ethylene propylene terpolymer is 100 parts, stearic acid is 2 parts, white carbon black is 30 parts, paraffin oil is 3-5 parts, antioxidant is 1-3 parts, modified copper powder is 10-20 parts, acrylonitrile grafted ethylene propylene terpolymer is 3-5 parts, zinc oxide coated aluminum nitride is 5-15 parts, sulfur is 0.5-1.5 parts, accelerator is 1-2 parts, auxiliary vulcanizing agent is 2 parts, auxiliary crosslinking agent is 2-3 parts.
[0009] Further, the modified copper powder preparation raw materials include copper powder, silane succinic anhydride, 1-allyl-1H-1,2,4-triazole-3-amine.
[0010] Further, the silane succinic anhydride is 3-(triethoxysilyl) propyl succinic anhydride and / or [3-(trimethoxysilyl) propyl] succinic anhydride.
[0011] Further, the modified copper powder preparation steps are as follows:
[0012] The silane succinic anhydride is added to anhydrous dimethyl sulfoxide, 1-allyl-1H-1,2,4-triazole-3-amine and triethylamine are added after stirring, the temperature is raised to 60-80 DEG C and stirring is carried out for 6-8 h, after the reaction is completed, the temperature is lowered to 25-35 DEG C, copper powder and ethanol solution are added, stirring is uniform, the temperature is raised to 50-60 DEG C and reaction is carried out for 12-24 h, after the reaction is completed, filtration is carried out, the filter cake is dried, and the modified copper powder is obtained.
[0013] The copper powder has good heat conduction performance, but is easy to oxidize, which damages its surface properties and heat conduction performance, and the combination degree with the ethylene propylene terpolymer is poor, which leads to large interface thermal resistance between the two, based on this, the silane succinic anhydride and 1-allyl-1H-1,2,4-triazole-3-amine are used as raw materials, under the catalysis of triethylamine, the amino group of 1-allyl-1H-1,2,4-triazole-3-amine is subjected to ring-opening reaction with the silane succinic anhydride, the intermediate product carrying siloxane structure, carboxyl, allyl and triazole is obtained, then the intermediate product is grafted on the surface of the copper powder through the hydrolysis condensation reaction of the siloxane structure, and the modified copper powder is obtained, through the modification treatment, one is to reduce the oxidation erosion of the copper powder by external oxygen and other media, so that the copper powder retains higher heat conduction performance, and the other is to improve the interface combination between the copper powder and the rubber matrix, and reduce the interface thermal resistance.
[0014] Further, the silane succinic anhydride, anhydrous dimethyl sulfoxide, 1-allyl-1H-1,2,4-triazole-3-amine, triethylamine, copper powder and ethanol solution are used in a ratio of 0.01 mol:60-100 mL:0.01 mol:0.01-0.015 mol:10-12 g:10-20 mL, and the mass fraction of the ethanol solution is 50-80%.
[0015] Further, the average particle size of the copper powder is 5-10 microns.
[0016] Further, the preparation steps of the zinc oxide coated aluminum nitride are as follows:
[0017] The aluminum nitride powder is added into anhydrous ethanol and ultrasonically dispersed for 1h, then ethanolamine and zinc acetate dihydrate are added, and the reaction is stirred at 45-55℃ for 6-10h. After the reaction is completed, the filter cake is vacuum dried at 100℃ until the weight is constant to obtain the zinc oxide coated aluminum nitride.
[0018] The aluminum nitride has high hygroscopicity and is prone to hydrolysis to produce aluminum hydroxide, thereby deteriorating the thermal conductivity. To this end, the zinc oxide is coated on the surface of the aluminum nitride to form a physical barrier to inhibit the hydrolysis of the aluminum nitride, and the uniformly dispersed zinc oxide is also beneficial to optimizing the vulcanization process of the ethylene propylene diene rubber, thereby obtaining the ethylene propylene diene rubber sealing material with better comprehensive performance.
[0019] Further, the amount ratio of the aluminum nitride powder, anhydrous ethanol, ethanolamine and zinc acetate dihydrate is 10g: 80-100mL: 0.68-1.0g: 1-1.5g.
[0020] Further, the average particle size of the aluminum nitride powder is 1-3μm.
[0021] Further, the preparation steps of the acrylonitrile grafted ethylene propylene diene rubber are as follows:
[0022] The ethylene propylene diene rubber is added into xylene, stirred for 5-10min, then the xylene solution of azobisisobutyronitrile is added, and then the xylene solution of acrylonitrile is added dropwise while stirring. After the dropwise addition is completed, the reaction is stirred at 65-75℃ for 2-4h. After the reaction is completed, the reaction product is precipitated with acetone while hot, and the precipitated product is extracted with DMF by Soxhlet extraction, dried, to obtain the acrylonitrile grafted ethylene propylene diene rubber.
[0023] Further, the mass ratio of the ethylene propylene diene rubber, azobisisobutyronitrile and acrylonitrile is 10: 0.5: 5-8.
[0024] Further, the antioxidant is composed of antioxidant RD (2,2,4-trimethyl-1,2-dihydroquinoline polymer) and antioxidant MB (2-mercaptobenzimidazole) according to a mass ratio of 1:1.
[0025] Further, the accelerator is composed of accelerator DM (dibenzothiazyl disulfide) and accelerator NS (N-tert-butyl-2-benzothiazole sulfenamide) according to a mass ratio of 1:1.
[0026] Further, the co-agents are di-tert-butyl peroxyisopropylbenzene and / or 1,4-bis-tert-butyl peroxyisopropylbenzene.
[0027] Further, the co-agents are triallyl isocyanurate.
[0028] The method for preparing the above-mentioned high thermal conductivity EPDM rubber sealing material comprises the following steps:
[0029] S1. Drying white carbon black, modified copper powder, zinc oxide-coated aluminum nitride, and EPDM rubber separately, and pre-mixing the dried zinc oxide-coated aluminum nitride and modified copper powder to obtain a thermally conductive filler;
[0030] S2, the dried EPDM rubber was put into an internal mixer, the mixer temperature was set to 100 ° C, the speed was 25-35 r / min, after mixing for 1.5-2.5 min, stearic acid and antioxidant were added, after mixing for 3.5-4.5 min, dry white carbon black, thermal conductive filler, acrylonitrile grafted EPDM rubber, paraffin oil were added, the speed was increased to 40-50 r / min, and after mixing for 5-8 min, the glue was discharged to obtain a mixed rubber;
[0031] S3. Put the mixed rubber into an open mill, mix for 2-4 minutes, then add sulfur, accelerator, vulcanizing agent and cross-linking agent, mix at 35-45°C for 5-10 minutes, leave for 12 hours, and then vulcanize on a flat vulcanizer to obtain a high thermal conductivity EPDM rubber sealing material.
[0032] Furthermore, the drying temperature is 75-85° C., and the drying time is 6-12 hours.
[0033] Furthermore, the speed during pre-mixing is 60-100 r / min and the time is 1-2 h.
[0034] Furthermore, the vulcanization temperature is 165-170° C., the vulcanization pressure is 10-15 MPa, and the vulcanization time is 10-15 min.
[0035] Beneficial effects of the present invention:
[0036] 1. The present invention provides a high thermal conductivity EPDM rubber sealing material, which uses modified copper powder and zinc oxide-coated aluminum nitride as thermally conductive fillers, and acrylonitrile-grafted EPDM rubber as a compatibilizer. The modified copper powder provides an in-plane thermal conduction path, the zinc oxide-coated aluminum nitride fills the gaps and blocks the conductivity of the modified copper powder, and the acrylonitrile-grafted EPDM rubber improves the bonding between the thermally conductive filler and the EPDM rubber matrix. The three work synergistically to achieve a final thermal conductivity of the sealing material of ≥2.1 W / (m·K). -1 , the volume resistivity is 10 14 Ω·cm, tensile strength ≥18.6MPa.
[0037] 2. The triazole groups and carboxyl groups on the surface of the modified copper powder can form coordinate bonds with zinc oxide coated aluminum nitride, and the nitrile groups in the acrylonitrile grafted ethylene propylene diene rubber can also form coordinate bonds with zinc oxide coated aluminum nitride. Multiple hydrogen bonds can also be formed between the triazole groups, nitrile groups and carboxyl groups. The introduction of multiple hydrogen bonds and coordinate bonds improves the interfacial bonding between the thermally conductive filler and the ethylene propylene diene rubber matrix, reduces the interfacial thermal resistance, makes the thermally conductive filler fully play the role of thermal conductivity, and the multiple hydrogen bonds and coordinate bonds are reversible sacrificial bonds, which are easier to break and dissipate energy when subjected to a load, thereby achieving the reinforcement and toughening of the sealing material.
[0038] 3. In the preparation process of the sealing material, the zinc oxide coated aluminum nitride and the modified copper powder are pre-mixed and assembled. Compared with adding the two in the ethylene propylene diene rubber system respectively, this pre-mixing operation is more conducive to forming a continuous, low-thermal-resistance, insulating and thermally conductive network in the subsequent mixing process, thereby improving the overall thermal conductivity of the sealing material. DETAILED DESCRIPTION
[0039] The technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.
[0040] In the present application, the ethylene propylene diene rubber is EPDM 4045, which is purchased from China Petroleum Jilin Petrochemical Company, and the remaining raw materials are commercially available products. The following will be specifically described in combination with the embodiments.
[0041] Preparation Example 1
[0042] The modified copper powder is prepared as follows:
[0043] 0.01 mol of 3-(triethoxysilyl)propyl succinic anhydride is added to 60 mL of anhydrous dimethyl sulfoxide, stirred uniformly, then 0.01 mol of 1-allyl-1H-1,2,4-triazole-3-amine and 0.01 mol of triethylamine are added, the temperature is raised to 60°C, and the reaction is stirred for 6 hours. After the reaction is completed, the temperature is lowered to 25°C, 10 g of copper powder (average particle size of 5-10 μm) and 10 mL of 50 wt% ethanol solution are added, and the mixture is stirred uniformly and then heated to 50°C for 12 hours. After the reaction is completed, the mixture is filtered, and the filter cake is dried in an oven at 80°C until the weight is constant to obtain the modified copper powder.
[0044] Preparation Example 2
[0045] The modified copper powder is prepared as follows:
[0046] Into 80 mL of anhydrous dimethyl sulfoxide, 0.01 mol of 3-(triethoxysilyl)propyl succinic anhydride was added, and after stirring, 0.01 mol of 1-allyl-1H-1,2,4-triazol-3-amine and 0.013 mol of triethylamine were added. The mixture was stirred at 70°C for 7 hours. After the reaction was completed, the mixture was cooled to 30°C, and 11 g of copper powder (average particle diameter: 5-10 μm) and 15 mL of a 60 wt% ethanol solution were added. The mixture was stirred at 55°C for 16 hours. After the reaction was completed, the mixture was filtered, and the filter cake was dried in an oven at 80°C until the weight was constant, thereby obtaining modified copper powder.
[0047] Preparation Example 3
[0048] Modified copper powder was prepared as follows:
[0049] Into 100 mL of anhydrous dimethyl sulfoxide, 0.01 mol of [3-(trimethoxysilyl)propyl]succinic anhydride was added, and after stirring, 0.01 mol of 1-allyl-1H-1,2,4-triazol-3-amine and 0.015 mol of triethylamine were added. The mixture was stirred at 80°C for 8 hours. After the reaction was completed, the mixture was cooled to 35°C, and 12 g of copper powder (average particle diameter: 5-10 μm) and 20 mL of a 80 wt% ethanol solution were added. The mixture was stirred at 60°C for 24 hours. After the reaction was completed, the mixture was filtered, and the filter cake was dried in an oven at 80°C until the weight was constant, thereby obtaining modified copper powder.
[0050] Comparative Example 1
[0051] Modified copper powder was prepared as follows:
[0052] Into 60 mL of anhydrous dimethyl sulfoxide, 0.01 mol of [3-(trimethoxysilyl)propyl]succinic anhydride was added, and after stirring, 10 g of copper powder (average particle diameter: 5-10 μm) and 10 mL of a 50 wt% ethanol solution were added. The mixture was stirred at 50°C for 12 hours. After the reaction was completed, the mixture was filtered, and the filter cake was dried in an oven at 80°C until the weight was constant, thereby obtaining modified copper powder.
[0053] Comparative Example 2
[0054] Modified copper powder was prepared as in Comparative Example 1, except that [3-(trimethoxysilyl)propyl]succinic anhydride was replaced with an equimolar amount of γ-aminopropyltriethoxysilane.
[0055] Example 1
[0056] A high-thermal-conductivity EPDM sealing material was prepared using the following raw materials (in parts by weight):
[0057] Ethylene propylene rubber 100 parts, stearic acid 2 parts, white carbon black 30 parts, paraffin oil 3 parts, antioxidant 1 part, modified copper powder of preparation example 1 10 parts, acrylonitrile grafted ethylene propylene rubber 3 parts, zinc oxide coated aluminum nitride 5 parts, sulfur 0.5 parts, accelerator 1 part, di-tert-butyl peroxide isopropyl benzene 2 parts, triallyl isocyanurate 2 parts.
[0058] The preparation steps of the zinc oxide coated aluminum nitride are as follows:
[0059] 10 g of aluminum nitride powder (average particle size 1-3 μm) was added to 80 mL of anhydrous ethanol and ultrasonically dispersed for 1 h, then 0.68 g of ethanolamine and 1 g of zinc acetate dihydrate were added, and the reaction was stirred at 45℃ for 6 h. After the reaction was completed, the filter cake was vacuum dried at 100℃ until the weight was constant to obtain zinc oxide coated aluminum nitride.
[0060] The preparation steps of the acrylonitrile grafted ethylene propylene rubber are as follows:
[0061] 10 g of ethylene propylene rubber was added to 100 mL of xylene, stirred for 5 min, then a solution composed of 0.5 g of azobisisobutyronitrile and 5 mL of xylene was added, then 5 g of acrylonitrile and 20 mL of xylene solution were added dropwise while stirring, after the dropwise addition was completed, the reaction was stirred at 65℃ for 2-4 h. After the reaction was completed, the reaction product was precipitated with acetone while hot, the precipitated product was Soxhlet extracted with DMF, and vacuum dried at 60℃ until the weight was constant to obtain acrylonitrile grafted ethylene propylene rubber.
[0062] The antioxidant is composed of antioxidant RD and antioxidant MB in a mass ratio of 1:1.
[0063] The accelerator is composed of accelerator DM and accelerator NS in a mass ratio of 1:1.
[0064] The preparation method of the high thermal conductivity ethylene propylene rubber sealing material described above comprises the following steps:
[0065] S1, the white carbon black, the modified copper powder, the zinc oxide coated aluminum nitride and the ethylene propylene rubber were respectively subjected to drying treatment, the drying temperature was 75℃, the drying time was 6 h, the dried zinc oxide coated aluminum nitride and the modified copper powder were pre-mixed, the pre-mixing speed was 60 r / min, the pre-mixing time was 1 h, and a thermal conductive filler was obtained.
[0066] S2, the dried ethylene propylene rubber was put into a mixer, the mixer temperature was set to 100℃, the rotation speed was 25 r / min, after mixing for 1.5 min, stearic acid and antioxidant were added, after mixing for 3.5 min, dry white carbon black, thermal conductive filler, acrylonitrile grafted ethylene propylene rubber and paraffin oil were added, the rotation speed was increased to 40 r / min, and after mixing for 5 min, the rubber was discharged, and a mixed rubber was obtained.
[0067] S3, the rubber is put into the open mill, after mixing for 2 minutes, sulfur, accelerator, di-tert-butyl peroxide isopropyl benzene and triallyl isocyanurate are added, mixing for 5 minutes at 35℃, after 12 hours of storage, the rubber is placed on the flat vulcanization machine for vulcanization treatment, the vulcanization temperature is 165℃, the vulcanization pressure is 10 MPa, and the vulcanization time is 10 minutes, thereby obtaining the high-thermal-conductivity EPDM sealing material.
[0068] Example 2
[0069] A high-thermal-conductivity EPDM sealing material, compared with Example 1, the only difference is that the high-thermal-conductivity EPDM sealing material in the present example comprises the following raw materials in parts by weight:
[0070] 100 parts of EPDM, 2 parts of stearic acid, 30 parts of white carbon black, 4 parts of paraffin oil, 2 parts of antioxidant, 15 parts of modified copper powder of Preparation 2, 4 parts of acrylonitrile grafted EPDM, 10 parts of zinc oxide coated aluminum nitride, 1 part of sulfur, 1.5 parts of accelerator, 2 parts of di-tert-butyl peroxide isopropyl benzene, and 2.5 parts of triallyl isocyanurate.
[0071] Example 3
[0072] A high-thermal-conductivity EPDM sealing material, compared with Example 1, the only difference is that the high-thermal-conductivity EPDM sealing material in the present example comprises the following raw materials in parts by weight:
[0073] 100 parts of EPDM, 2 parts of stearic acid, 30 parts of white carbon black, 5 parts of paraffin oil, 3 parts of antioxidant, 20 parts of modified copper powder of Preparation 3, 5 parts of acrylonitrile grafted EPDM, 15 parts of zinc oxide coated aluminum nitride, 1.5 parts of sulfur, 2 parts of accelerator, 2 parts of di-tert-butyl peroxide isopropyl benzene, and 3 parts of triallyl isocyanurate.
[0074] Example 4
[0075] A high-thermal-conductivity EPDM sealing material, compared with Example 1, the only difference is that the zinc oxide coated aluminum nitride in the present example is prepared by the following steps:
[0076] 10 g of aluminum nitride powder (average particle size of 1-3 μm) is added into 100 mL of anhydrous ethanol and ultrasonically dispersed for 1 h, then 0.85 g of ethanolamine and 1.2 g of zinc acetate dihydrate are added, and the mixture is stirred at 50℃ for 8 h. After the reaction is completed, the mixture is filtered, and the filter cake is vacuum dried at 100℃ until the weight is constant, thereby obtaining the zinc oxide coated aluminum nitride.
[0077] Example 5
[0078] A high-thermal-conductivity EPDM sealing material, compared with Example 1, the only difference is that the zinc oxide coated aluminum nitride in the present example is prepared by the following steps:
[0079] 10 g of aluminum nitride powder (average particle size of 1-3 μm) was added to 100 mL of anhydrous ethanol and ultrasonically dispersed for 1 h, then 1.0 g of ethanolamine and 1.5 g of zinc acetate dihydrate were added, and the reaction was stirred at 55°C for 10 h. After the reaction was completed, the filter cake was vacuum dried at 100°C to constant weight to obtain zinc oxide-coated aluminum nitride.
[0080] Example 6
[0081] A high-thermal-conductivity EPDM sealing material, compared with Example 1, differs only in that the preparation steps of the acrylonitrile grafted EPDM in this example are as follows:
[0082] 10 g of EPDM was added to 100 mL of xylene, stirred for 10 min, then a solution composed of 0.5 g of azobisisobutyronitrile and 5 mL of xylene was added, then a solution composed of 8 g of acrylonitrile and 20 mL of xylene was added dropwise while stirring, after the dropwise addition was completed, the reaction was stirred at 75°C for 4 h. After the reaction was completed, the reaction product was precipitated using acetone while hot, the precipitated product was vacuum dried at 60°C to constant weight using a DMF soxhlet extraction method to obtain acrylonitrile grafted EPDM.
[0083] Example 7
[0084] A high-thermal-conductivity EPDM sealing material, compared with Example 1, differs only in that the preparation steps of the acrylonitrile grafted EPDM in this example are as follows:
[0085] 10 g of EPDM was added to 100 mL of xylene, stirred for 6 min, then a solution composed of 0.5 g of azobisisobutyronitrile and 5 mL of xylene was added, then a solution composed of 6.5 g of acrylonitrile and 20 mL of xylene was added dropwise while stirring, after the dropwise addition was completed, the reaction was stirred at 70°C for 3 h. After the reaction was completed, the reaction product was precipitated using acetone while hot, the precipitated product was vacuum dried at 60°C to constant weight using a DMF soxhlet extraction method to obtain acrylonitrile grafted EPDM.
[0086] Example 8
[0087] A high-thermal-conductivity EPDM sealing material, compared with Example 1, differs only in that the preparation method of the high-thermal-conductivity EPDM sealing material in this example includes the following steps:
[0088] S1, fumed silica, modified copper powder, zinc oxide-coated aluminum nitride, and EPDM were respectively subjected to drying treatment, the drying temperature was 85°C, and the drying time was 12 h. The dried zinc oxide-coated aluminum nitride and modified copper powder were pre-mixed, the pre-mixing speed was 100 r / min, and the pre-mixing time was 12 h to obtain a thermal conductive filler.
[0089] S2, the dried EPDM rubber is put into the internal mixer, the mixer temperature is set to 100℃, the speed is 35r / min, after mixing for 2.5min, stearic acid and antioxidant are added, after mixing for 4.5min, dry white carbon black, heat-conducting filler, acrylonitrile grafted EPDM rubber and paraffin oil are added, the speed is increased to 50r / min, after mixing for 8min, the rubber is discharged, and the rubber compound is obtained;
[0090] S3, the rubber compound is put into the open mill, after mixing for 4min, sulfur, accelerator, di-tert-butyl peroxide isopropyl benzene and triallyl isocyanurate are added, mixing is carried out at 45℃ for 10min, after standing for 12h, the rubber compound is placed on the flat vulcanizing machine for vulcanization treatment, the vulcanization temperature is 170℃, the vulcanization pressure is 15MPa, and the vulcanization time is 15min, and the high-thermal-conductivity EPDM rubber sealing material is obtained.
[0091] Comparative Example 1
[0092] A high-thermal-conductivity EPDM rubber sealing material, compared with Example 1, only differs in that the modified copper powder in Example 1 is replaced by the product prepared in Comparative Example 1.
[0093] Comparative Example 2
[0094] A high-thermal-conductivity EPDM rubber sealing material, compared with Example 1, only differs in that the modified copper powder in Example 1 is replaced by the product prepared in Comparative Example 2.
[0095] Comparative Example 3
[0096] A high-thermal-conductivity EPDM rubber sealing material, compared with Example 1, only differs in that the zinc oxide coated aluminum nitride in Example 1 is replaced by the physical mixture of equal mass of nano zinc oxide and aluminum nitride (average particle size is 1-3μm), and the preparation process of the physical mixture of nano zinc oxide and aluminum nitride (average particle size is 1-3μm) is as follows:
[0097] The nano zinc oxide and aluminum nitride are added into the mixer at a mass ratio of 10:0.4, and mixed at 200r / min for 30min.
[0098] Comparative Example 4
[0099] A high-thermal-conductivity EPDM rubber sealing material, compared with Example 1, only differs in that the acrylonitrile grafted EPDM rubber in Example 1 is replaced by equal mass of EPDM rubber.
[0100] Comparative Example 5
[0101] A high-thermal-conductivity EPDM rubber sealing material, compared with Example 1, only differs in that the modified copper powder in Example 1 is replaced by equal mass of zinc oxide coated aluminum nitride.
[0102] Comparative Example 6
[0103] A high-thermal-conductivity EPDM sealing material, compared with Example 1, the only difference is that the zinc oxide coated aluminum nitride in Example 1 is replaced by the same mass of modified copper powder.
[0104] Comparative Example 7
[0105] A high-thermal-conductivity EPDM sealing material, compared with Example 1, the only difference is that the preparation method of the high-thermal-conductivity EPDM sealing material in the present example comprises the following steps:
[0106] S1, dry treatment of fumed silica, modified copper powder, zinc oxide coated aluminum nitride and EPDM respectively, the drying temperature is 75℃, and the drying time is 6h;
[0107] S2, put the dried EPDM into the internal mixer, set the mixer temperature to 100℃, and the rotation speed to 25r / min, mix for 1.5min, then add stearic acid and antioxidant, mix for 3.5min, then add dry fumed silica, dry modified copper powder, dry zinc oxide coated aluminum nitride, acrylonitrile grafted EPDM and paraffin oil, increase the rotation speed to 40r / min, mix for 5min, then discharge the glue, and get the mixed rubber;
[0108] S3, put the mixed rubber into the open mill, mix for 2min, then add sulfur, accelerator, di-tert-butyl peroxide isopropyl benzene and triallyl isocyanurate, mix at 35℃ for 5min, then place for 12h, and then put it into the flat vulcanizing machine for vulcanization treatment, the vulcanization temperature is 165℃, the vulcanization pressure is 10MPa, and the vulcanization time is 10min, and get the high-thermal-conductivity EPDM sealing material.
[0109] The sealing materials obtained in Examples 1-8 and Comparative Examples 1-7 are tested for performance, and the test method is as follows:
[0110] The tensile properties are tested according to GB / T528-2009, and I-shaped dumbbell-shaped samples are used;
[0111] The thermal conductivity is measured by a thermal conductivity analyzer, and the size of the circular sheet sample is 12.7mm in diameter and 2mm in thickness;
[0112] The volume resistivity is tested according to GB / T 2439-2001;
[0113] The results are shown in Table 1:
[0114] Table 1
[0115]
[0116] It can be seen from the test results of Examples 1 to 8 in Table 1 that the final thermal conductivity of the sealing material of the present application is ≥ 2.1 [W / (m·K) -1 ], volume resistivity is 10 14 Ω·cm, tensile strength ≥18.6MPa; among them, Example 2 has the best overall performance;
[0117] It can be seen from the test results in Example 1, Comparative Example 1 and Comparative Example 2 that, compared with the copper powder modified with [3-(trimethoxysilyl)propyl]succinic anhydride or γ-aminopropyltriethoxysilane, the modified copper powder prepared in the present application has better compatibility with other components of the sealing material, and the obtained sealing material has higher mechanical properties, thermal conductivity and insulation properties;
[0118] It can be seen from the test results in Example 1 and Comparative Example 3 that, compared with the physical mixture of zinc oxide and aluminum nitride, the zinc oxide-coated aluminum nitride prepared in the present application is conducive to the uniform dispersion of zinc oxide and has better compatibility with other components of the sealing material;
[0119] It can be seen from the test results of Example 1 and Comparative Example 4 that replacing the acrylonitrile-grafted EPDM rubber with an equal mass of EPDM rubber leads to weakening of hydrogen bonds and coordination bonds in the rubber system, which is not conducive to obtaining high-performance sealing materials;
[0120] From the test results of Example 1, Comparative Example 5 and Comparative Example 6, it can be seen that there is a synergistic effect between the modified copper powder and the zinc oxide-coated aluminum nitride in the present application, which cooperate with each other to obtain a high thermal conductivity insulating sealing material;
[0121] It can be seen from the test results of Example 1 and Comparative Example 7 that not pre-mixing the modified copper powder and the zinc oxide-coated aluminum nitride is not conducive to obtaining a high-performance sealing material.
[0122] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.
[0123] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.
Claims
1. A high thermal conductivity EPDM rubber sealing material, characterized in that: It includes the following raw materials in parts by weight: 100 parts of EPDM rubber, 2 parts of stearic acid, 30 parts of white carbon black, 3-5 parts of paraffin oil, 1-3 parts of antioxidant, 10-20 parts of modified copper powder, 3-5 parts of acrylonitrile-grafted EPDM rubber, 5-15 parts of zinc oxide-coated aluminum nitride, 0.5-1.5 parts of sulfur, 1-2 parts of accelerator, 2 parts of vulcanizing agent, and 2-3 parts of cross-linking agent; The raw materials for preparing the modified copper powder include copper powder, silylsuccinic anhydride, and 1-allyl-1H-1,2,4-triazole-3-amine.
2. The high thermal conductivity EPDM rubber sealing material according to claim 1, characterized in that: The silylsuccinic anhydride is 3-(triethoxysilyl)propylsuccinic anhydride and / or [3-(trimethoxysilyl)propyl]succinic anhydride.
3. The high thermal conductivity EPDM rubber sealing material according to claim 1, characterized in that: The modified copper powder preparation steps are as follows: Add silylsuccinic anhydride to anhydrous dimethyl sulfoxide, stir evenly, then add 1-allyl-1H-1,2,4-triazole-3-amine and triethylamine, heat to 60-80°C and stir to react for 6-8 hours. After the reaction is completed, cool to 25-35°C, add copper powder and ethanol solution, stir evenly, then heat to 50-60°C and react for 12-24 hours. After the reaction is completed, filter with suction, and dry the filter cake to obtain modified copper powder.
4. The high thermal conductivity EPDM rubber sealing material according to claim 3, characterized in that: The dosage ratio of silylsuccinic anhydride, anhydrous dimethyl sulfoxide, 1-allyl-1H-1,2,4-triazole-3-amine, triethylamine, copper powder and ethanol solution is 0.01 mol: 60-100 mL: 0.01 mol: 0.01-0.015 mol: 10-12 g: 10-20 mL, and the mass fraction of the ethanol solution is 50-80%.
5. The high thermal conductivity EPDM rubber sealing material according to claim 1, characterized in that: The preparation steps of the zinc oxide coated aluminum nitride are as follows: Aluminum nitride powder was added to anhydrous ethanol and ultrasonically dispersed for 1 hour, followed by addition of ethanolamine and zinc acetate dihydrate, and the mixture was stirred and reacted at 45-55° C. for 6-10 hours. After the reaction was completed, the mixture was filtered, and the filter cake was vacuum dried at 100° C. to constant weight to obtain zinc oxide-coated aluminum nitride.
6. The high thermal conductivity EPDM rubber sealing material according to claim 5, characterized in that: The dosage ratio of aluminum nitride powder, anhydrous ethanol, ethanolamine and zinc acetate dihydrate is 10g:80-100mL:0.68-1.0g:1-1.5g.
7. The high thermal conductivity EPDM rubber sealing material according to claim 1, characterized in that: The acrylonitrile grafted EPDM rubber preparation steps are as follows: Add EPDM rubber to xylene, stir and add xylene solution of azobisisobutyronitrile, then add acrylonitrile solution in xylene dropwise while stirring. After the addition is complete, stir and react at 65-75°C for 2-4 hours. After the reaction is completed, precipitate the reaction product with acetone while it is hot, extract the precipitate with DMF Soxhlet method, and dry to obtain acrylonitrile-grafted EPDM rubber.
8. The high thermal conductivity EPDM rubber sealing material according to claim 7, characterized in that: The mass ratio of EPDM rubber, azobisisobutyronitrile and acrylonitrile is 10:0.5:5-8.
9. A method for preparing a high thermal conductivity EPDM rubber sealing material, characterized in that: The method for preparing the high thermal conductivity EPDM rubber sealing material according to any one of claims 1 to 8 comprises the following steps: S1. Drying white carbon black, modified copper powder, zinc oxide-coated aluminum nitride, and EPDM rubber separately, and pre-mixing the dried zinc oxide-coated aluminum nitride and modified copper powder to obtain a thermally conductive filler; S2, the dried EPDM rubber was put into an internal mixer, the mixer temperature was set to 100 ° C, the speed was 25-35 r / min, after mixing for 1.5-2.5 min, stearic acid and antioxidant were added, after mixing for 3.5-4.5 min, dry white carbon black, thermal conductive filler, acrylonitrile grafted EPDM rubber, paraffin oil were added, the speed was increased to 40-50 r / min, and after mixing for 5-8 min, the glue was discharged to obtain a mixed rubber; S3. Put the mixed rubber into an open mill, mix for 2-4 minutes, then add sulfur, accelerator, vulcanizing agent and cross-linking agent, mix at 35-45°C for 5-10 minutes, leave for 12 hours, and then vulcanize on a flat vulcanizer to obtain a high thermal conductivity EPDM rubber sealing material.
10. The method for preparing a high thermal conductivity EPDM rubber sealing material according to claim 9, characterized in that: The vulcanization temperature is 165-170°C, the vulcanization pressure is 10-15MPa, and the vulcanization time is 10-15min.