Ethylene-propylene-diene monomer material for cable accessories and preparation method of ethylene-propylene-diene monomer material

Abstract

The invention relates to the technical field of high polymer materials, in particular to an ethylene propylene diene monomer material for cable accessories and a preparation method of the ethylene propylene diene monomer material. The ethylene propylene diene monomer material for the cable accessories is prepared from the following raw materials in parts by weight: 100 parts of ethylene propylene diene monomer, 6-12 parts of paraffin oil, 20-30 parts of white carbon black, 20-30 parts of a functional additive, 10-20 parts of zinc borate, 10-20 parts of calcined clay, 2-4 parts of zinc oxide, 1-2 parts of cerium oxide, 1-2 parts of stearic acid, 2-3 parts of an anti-aging agent, 2-3 parts of a silane coupling agent and 3-6 parts of a vulcanizing agent. 1-2 parts of an accelerant and 1-3 parts of an antioxidant; the ethylene propylene diene monomer material prepared by the invention not only has excellent flame retardant property, but also has good ultraviolet aging resistance, the aging phenomenon of the ethylene propylene diene monomer material caused by ultraviolet irradiation can be effectively reduced, and the service life of the ethylene propylene diene monomer material is prolonged to a certain extent while the quality of the ethylene propylene diene monomer material is ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high polymer materials, in particular to a kind of EPDM material for cable accessory and preparation method thereof. BACKGROUND

[0002] EPDM is widely used in the field of cable accessories due to its excellent weather resistance, electrical insulation and chemical stability. In the field of cable accessories, EPDM is often used to make key components such as stress cone and insulating sleeve. However, with the rapid development of modern power industry, the performance requirements of cable accessories are becoming increasingly stringent. On the one hand, the cable operating environment is complex and variable, and may face high temperature, high humidity, strong ultraviolet radiation and various chemical substance corrosion, etc. Therefore, the EPDM material for cable accessories must have excellent anti-aging performance, especially ultraviolet aging resistance, to ensure long-term stable operation. On the other hand, with the continuous increase of power transmission capacity, higher standards for the flame retardant performance of materials are required. Once a fire occurs, the material must have good flame retardant effect to prevent the spread of fire and ensure the safety of power system Based on the above, the present application provides a preparation method of EPDM material for cable accessory, aiming to solve the above technical problems. SUMMARY

[0003] The EPDM material prepared by the present application not only has excellent flame retardant performance, but also has good ultraviolet aging resistance, which can effectively reduce the aging phenomenon of EPDM material caused by ultraviolet radiation, thereby prolonging the service life of the material to a certain extent while ensuring its quality.

[0004] To achieve the above purpose, the present application provides the following technical solutions: An EPDM material for cable accessory, comprising the following raw materials by weight: 100 parts of EPDM, 6-12 parts of paraffin oil, 20-30 parts of white carbon black, 20-30 parts of functional additives, 10-20 parts of zinc borate, 10-20 parts of calcined clay, 2-4 parts of zinc oxide, 1-2 parts of cerium oxide, 1-2 parts of stearic acid, 2-3 parts of antioxidant, 2-3 parts of silane coupling agent, 3-6 parts of vulcanizing agent, 1-2 parts of accelerator and 1-3 parts of antioxidant.

[0005] Further, the Mooney viscosity ML (1+4, 125℃) of the EPDM is ≥55, the ethylene content is ≥55%, and the ENB content is ≤4.5%.

[0006] Further, the preparation method of the functional additive is as follows: Step one, under the nitrogen atmosphere, the pentaerythritol phosphate is dissolved in toluene with the dosage of 20-50 g / L, then the ultraviolet absorber UV-328 and potassium carbonate are added, and the reaction is carried out at 80-90℃ for 5-8h, the alkaline solution is used to absorb the generated irritating gas during the reaction, after the reaction is completed, the product components are filtered to remove the inorganic salt by-product, and the toluene in the filtrate is recovered by reduced pressure distillation, and the remaining components are marked as intermediate; wherein, the dosage of ultraviolet absorber UV-328 and potassium carbonate is 70-75%, 3-5% of pentaerythritol phosphate respectively; Step two, the intermediate is dissolved in toluene with the solid-liquid ratio of 1:10-20, and the silane coupling agent KH-550 with the mass of 0.5-0.6 times of the intermediate is added dropwise under stirring and nitrogen protection, and then the reaction is carried out at 100-110℃ for 5-8h; the obtained reaction liquid is cooled to room temperature, toluene is removed by reduced pressure distillation, and then the product is recrystallized from anhydrous ethanol (the dosage of ethanol is 3-5 L / kg, and the recrystallization temperature is 70℃), and vacuum dried to obtain the modifier; Step three, the modifier is put into the ethanol aqueous solution with the volume concentration of 20-30% with the solid-liquid ratio of 1:6-10, and then the pH is adjusted to 4-5 by acetic acid, and the ultrasonic dispersion is carried out at the power of 100-150W for 20-30min; the obtained mixture is slowly dropped into the inorganic substrate aqueous dispersion liquid with the volume of 3-5 times and the concentration of 20-50g / L, and then the ultrasonic dispersion is carried out at the power of 250-350W for 15-25min, and then the reaction is carried out at 70-80℃ for 3-5h; the obtained reaction liquid is cooled to room temperature, and then filtered, washed (ethanol and deionized water are alternately washed for 3-4 times) and vacuum dried (dried at 75-85℃ until the constant weight) to obtain the functional aid; wherein, the inorganic substrate is composed of sepiolite and the magnesium hydroxide coating layer on the surface of sepiolite.

[0007] Further, the preparation method of the inorganic substrate is as follows: the sepiolite powder acidified by hydrochloric acid is added into the magnesium nitrate aqueous solution with the concentration of 0.3-0.6 mol / L, and the mass of the sepiolite powder is 0.2-0.4 times of the magnesium nitrate, and then the sodium hydroxide aqueous solution with the concentration of 2-4 mol / L is slowly added dropwise after uniform dispersion, the pH is controlled to be 10-11, and the reaction is carried out at 60-80℃ for 3-5h, and then the reaction product is sequentially filtered, washed and dried (dried at 60-80℃ for 3-4h) to obtain the inorganic substrate. The preparation method of the sepiolite powder acidified by hydrochloric acid is as follows: the sepiolite powder with the particle size of 2-5μm is soaked in the hydrochloric acid solution with the concentration of 1-3 mol / L with the solid-liquid ratio of 1:8-10, and then the reaction is carried out at 30-35℃ for 2-5h, and then the supernatant is removed, and the product is washed to neutral and dried.

[0008] Further, the antioxidant is selected from any one of antioxidant RD (2,2,4-trimethyl-1,2-dihydroquinoline polymer), antioxidant MB (2-mercaptobenzimidazole), and antioxidant MBZ (2-mercaptobenzimidazole zinc salt).

[0009] Further, the silane coupling agent is selected from any one of silane coupling agent KH-570, silane coupling agent KH-550, silane coupling agent KH-560, and silane coupling agent KH-580.

[0010] Further, the vulcanizing agent is selected from any one of sulfur, dicumyl peroxide, and dibenzoyl peroxide.

[0011] Further, the accelerator is selected from any one of tetramethylthiuram disulfide, 2-mercaptobenzothiazole, triallyl isocyanurate, and N-cyclohexyl-2-benzothiazole sulfenamide.

[0012] Further, the antioxidant is selected from any one of tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]pentaerythritol ester and tris(2,4-di-tert-butylphenyl) phosphite.

[0013] A preparation method of a ternary ethylene-propylene-diene rubber material for cable accessories, comprising the following steps: Step one, ternary ethylene-propylene-diene rubber, zinc oxide, cerium oxide, stearic acid, antioxidant, and paraffin oil are added into a mixer, and after mixing at 70-90 DEG C for 3-5 min, white carbon black and silane coupling agent are added, and mixing is carried out at 80-100 DEG C for 3-6 min; Step two, after mixing, functional additives and zinc borate are added, and mixing is carried out at 80-100 DEG C for 2-5 min, and then the rubber compound is discharged; the rubber compound is transferred to an open mill, and after thin passing for 3-5 times, the remaining raw materials are added and mixed uniformly at 40-60 DEG C; Step three, the obtained rubber compound is transferred into a mold, and vulcanization is carried out at 160-170 DEG C and 10-15 MPa for 30-40 min.

[0014] Compared with the prior art, the present application has the following beneficial effects: Under a nitrogen atmosphere, pentaerythritol phosphate and UV absorber UV-328 were added to toluene. In the presence of potassium carbonate, the phenolic hydroxyl group on the UV-328 molecule nucleophilically attacked the phosphorus-chlorine covalent bond on the pentaerythritol phosphate molecule, forming a phosphate ester bond through substitution, thus chemically linking the two molecules. The resulting intermediate was dissolved in toluene, and silane coupling agent KH-550 was added. The amino group on the KH-550 molecule nucleophilically attacked the phosphorus-oxygen double bond of the intermediate, forming a phosphorus-nitrogen covalent bond and removing hydrogen chloride, ultimately yielding the modifier. The prepared modifier possesses the dual properties of pentaerythritol phosphate and UV absorber UV-328, giving it not only excellent flame retardant properties but also good resistance to UV aging.

[0015] This invention involves immersing hydrochloric acid-acidified sepiolite powder in an aqueous magnesium nitrate solution, resulting in the deposition of a dense magnesium hydroxide coating layer on the surface and within the porous structure of the sepiolite powder, thus creating an inorganic substrate with sepiolite powder as the core and the magnesium hydroxide coating layer as the shell. The inorganic substrate is then formulated into an aqueous dispersion, and a mixture containing a modifier is added. In this mixture, the modifier undergoes complete hydrolysis, and the silanol groups on its surface undergo a dehydration condensation reaction with the hydroxyl groups on the inorganic substrate surface. Ultimately, the modifier is effectively grafted onto the surface of the inorganic substrate through chemical bonds, yielding a functional additive composed of sepiolite powder, a magnesium hydroxide coating layer, and the modifier. This "grafting" of the modifier not only significantly improves the flame retardant properties of the inorganic substrate but also significantly enhances its UV aging resistance.

[0016] The prepared functional additives, when used as raw materials for EPDM rubber materials for cable accessories, not only significantly improve the flame retardant properties of EPDM rubber with the synergistic effect of sepiolite powder, magnesium hydroxide, and modifiers, but also significantly enhance its UV aging resistance, effectively reducing the aging phenomenon caused by UV radiation in EPDM rubber materials. This ensures its quality while extending its service life to a certain extent. Detailed Implementation

[0017] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0018] Example 1 A type of EPDM rubber material for cable accessories is composed of the following raw materials in parts by weight: 100 parts EPDM rubber, 6 parts paraffin oil, 20 parts silica, 20 parts functional additives, 10 parts zinc borate, 10 parts calcined clay, 2 parts zinc oxide, 1 part cerium oxide, 1 part stearic acid, 2 parts antioxidant RD, 2 parts silane coupling agent KH-570, 3 parts sulfur, 1 part tetramethylthiuram disulfide, and 1 part pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid].

[0019] The EPDM rubber was purchased from Shaanxi Yanchang Petroleum Yan'an Energy and Chemical Co., Ltd. The EPDM-Y-05H4D4 EPDM rubber has a Mooney viscosity (ML1+4, 125℃) of 59.4, an ethylene content of 57.82%, and an ENB content of 4.07%. The calcined clay is EPDMY-1 type calcined clay produced by Guangxi Lianzhuang Technology Co., Ltd.

[0020] The preparation method of the functional additive is as follows: Step 1: Under a nitrogen atmosphere, pentaerythritol phosphate was dissolved in toluene at a dosage ratio of 20 g / L. UV absorber UV-328 and potassium carbonate were added, and the mixture was reacted at 80°C for 8 hours. During the reaction, the generated irritating gases were absorbed with alkaline solution. After the reaction was complete, the product components were filtered while hot to remove inorganic salt byproducts. Toluene was recovered from the filtrate by vacuum distillation. The remaining components were designated as intermediates. The amounts of UV absorber UV-328 and potassium carbonate were 70% and 3% of the amount of pentaerythritol phosphate, respectively. Step 2: Dissolve the intermediate in toluene at a solid-liquid ratio of 1:10. Under nitrogen protection, add 0.5 times the mass of the intermediate of silane coupling agent KH-550 dropwise with stirring. Then, stir and react at 100℃ for 5-8 hours. Cool the resulting reaction solution to room temperature, remove the toluene by vacuum distillation, recrystallize with anhydrous ethanol (ethanol dosage is 3 L / kg, recrystallization temperature is 70℃), and vacuum dry to obtain the modifier. Step 3: Add the modifier to a 20% (v / v) ethanol aqueous solution at a solid-liquid ratio of 1:6. Adjust the pH to 4 with acetic acid and then ultrasonically disperse at 100W for 30 min. Slowly drop the resulting mixture into an inorganic substrate aqueous dispersion with a concentration of 20 g / L, three times its volume. Ultrasonically disperse at 250W for 25 min and then keep warm and stir at 70℃ for 5 h. After cooling the resulting reaction solution to room temperature, filter it and then wash it (alternating between ethanol and deionized water three times) and vacuum dry it (dry at 75℃ to constant weight) to obtain the functional additive. The inorganic substrate consists of sepiolite and a magnesium hydroxide coating layer on its surface.

[0021] The inorganic substrate is prepared by adding hydrochloric acid-acidified sepiolite powder (0.2 times the mass of magnesium nitrate) to a 0.3 mol / L magnesium nitrate aqueous solution, dispersing it evenly, and then slowly adding a 2 mol / L sodium hydroxide aqueous solution, controlling the pH to 10. After reacting at 60℃ for 5 hours, the reaction product is filtered, washed, and dried (dried at 60℃ for 4 hours) to obtain the final product.

[0022] The preparation method of hydrochloric acid-acidified sepiolite is as follows: immerse sepiolite powder with a particle size of 3μm in a 2mol / L hydrochloric acid solution at a solid-liquid ratio of 1:10, stir at 35℃ for 5h, then remove the supernatant, wash with water until neutral, and then dry.

[0023] A method for preparing EPDM rubber material for cable accessories includes the following steps: Step 1: Add EPDM rubber, zinc oxide, cerium oxide, stearic acid, antioxidant, and paraffin oil to a mixer and mix at 70°C for 5 minutes. Then add silica and silane coupling agent and mix at 80°C for 6 minutes. Step 2: After mixing, add functional additives and zinc borate, mix at 80°C for 5 minutes, and then discharge the rubber to obtain the compound. Transfer the compound to a two-roll mill, pass it through a thin mill 5 times, add the remaining raw materials, and mix at 40°C. Step 3: Transfer the obtained rubber compound into the mold and vulcanize it at 165℃ and 12MPa for 35 minutes.

[0024] Example 2 The preparation method of the EPDM rubber material for cable accessories provided in this embodiment is basically the same as that in Example 1, except that the specific preparation methods of the functional additives and modifiers used are different. The specific preparation methods of the functional additives and modifiers in this embodiment are as follows: A type of EPDM rubber material for cable accessories is composed of the following raw materials in parts by weight: 100 parts EPDM rubber, 10 parts paraffin oil, 25 parts silica, 25 parts functional additives, 15 parts zinc borate, 15 parts calcined clay, 3 parts zinc oxide, 2 parts cerium oxide, 2 parts stearic acid, 3 parts antioxidant MB, 3 parts silane coupling agent KH-550, 4 parts dicumyl peroxide, 2 parts dicumyl peroxide and 2 parts tris(2,4-di-tert-butylphenyl) phosphite.

[0025] The preparation method of the functional additive is as follows: Step 1: Under a nitrogen atmosphere, pentaerythritol phosphate was dissolved in toluene at a dosage ratio of 30 g / L. UV absorber UV-328 and potassium carbonate were added, and the mixture was reacted at 85°C for 6 hours. During the reaction, the generated irritating gases were absorbed with alkaline solution. After the reaction was complete, the product components were filtered while hot to remove inorganic salt byproducts. Toluene was recovered from the filtrate by vacuum distillation. The remaining components were designated as intermediates. The amounts of UV absorber UV-328 and potassium carbonate were 75% and 4% of the amount of pentaerythritol phosphate, respectively. Step 2: Dissolve the intermediate in toluene at a solid-liquid ratio of 1:15. Under nitrogen protection, add 0.6 times the mass of the intermediate of silane coupling agent KH-550 dropwise with stirring. Then, stir and react at 100°C for 6 hours. Cool the resulting reaction solution to room temperature, remove the toluene by vacuum distillation, recrystallize with anhydrous ethanol (ethanol dosage is 4 L / kg, recrystallization temperature is 70°C), and vacuum dry to obtain the modifier. Step 3: Add the modifier to a 25% (v / v) ethanol aqueous solution at a solid-liquid ratio of 1:8. Adjust the pH to 4.5 with acetic acid and then ultrasonically disperse at 150W for 25 min. Slowly drop the resulting mixture into an inorganic substrate aqueous dispersion with a volume of 40 g / L and a concentration of 4 times the volume of the mixture. Ultrasonically disperse at 300W for 20 min and then keep warm and stir at 75℃ for 4 h. After cooling the resulting reaction solution to room temperature, filter it and then wash it (alternating between ethanol and deionized water 4 times) and vacuum dry it (dry at 80℃ to constant weight) to obtain the functional additive. The inorganic substrate consists of sepiolite and a magnesium hydroxide coating layer on its surface.

[0026] The inorganic substrate is prepared by adding hydrochloric acid-acidified sepiolite powder (0.3 times the mass of magnesium nitrate) to a 0.5 mol / L magnesium nitrate aqueous solution, dispersing it evenly, and then slowly adding a 3 mol / L sodium hydroxide aqueous solution, controlling the pH to 10.5. After reacting at 70℃ for 4 hours, the reaction product is filtered, washed, and dried (drying at 70℃ for 4 hours) to obtain the substrate.

[0027] Example 3 The preparation method of the EPDM rubber material for cable accessories provided in this embodiment is basically the same as that in Example 1, except that the specific preparation methods of the functional additives and modifiers used are different. The specific preparation methods of the functional additives and modifiers in this embodiment are as follows: A type of EPDM rubber material for cable accessories is composed of the following raw materials in parts by weight: 100 parts EPDM rubber, 12 parts paraffin oil, 30 parts silica, 30 parts functional additives, 20 parts zinc borate, 20 parts calcined clay, 4 parts zinc oxide, 2 parts cerium oxide, 2 parts stearic acid, 3 parts antioxidant MBZ, 3 parts silane coupling agent KH-560, 6 parts benzoyl peroxide, 2 parts triallyl isocyanurate, and 3 parts pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate].

[0028] The preparation method of the functional additive is as follows: Step 1: Under a nitrogen atmosphere, pentaerythritol phosphate was dissolved in toluene at a dosage ratio of 50 g / L. UV absorber UV-328 and potassium carbonate were added, and the mixture was reacted at 90°C for 5 hours. During the reaction, the generated irritating gases were absorbed with alkaline solution. After the reaction was complete, the product components were filtered while hot to remove inorganic salt byproducts. Toluene was recovered from the filtrate by vacuum distillation. The remaining components were designated as intermediates. The amounts of UV absorber UV-328 and potassium carbonate were 75% and 5% of the amount of pentaerythritol phosphate, respectively. Step 2: Dissolve the intermediate in toluene at a solid-liquid ratio of 1:20. Under nitrogen protection, add 0.6 times the mass of the intermediate of silane coupling agent KH-550 dropwise with stirring. Then, stir and react at 110℃ for 5 hours. Cool the resulting reaction solution to room temperature, remove the toluene by vacuum distillation, recrystallize with anhydrous ethanol (ethanol dosage is 5L / kg, recrystallization temperature is 70℃) and vacuum dry to obtain the modifier. Step 3: Add the modifier to a 30% (v / v) ethanol aqueous solution at a solid-liquid ratio of 1:10. Adjust the pH to 5 with acetic acid and then ultrasonically disperse at 150W for 20 minutes. Slowly drop the resulting mixture into an inorganic substrate aqueous dispersion with a volume of 5 times the volume and a concentration of 50 g / L. Ultrasonically disperse at 350W for 15 minutes and then keep warm and stir at 80℃ for 3 hours. After cooling the resulting reaction solution to room temperature, filter it and then wash it (alternating between ethanol and deionized water 4 times) and vacuum dry it (dry at 85℃ to constant weight) to obtain the functional additive. The inorganic substrate consists of sepiolite and a magnesium hydroxide coating layer on its surface.

[0029] The inorganic substrate is prepared by adding hydrochloric acid-acidified sepiolite powder (0.4 times the mass of magnesium nitrate) to a 0.6 mol / L magnesium nitrate aqueous solution, dispersing it evenly, and then slowly adding a 4 mol / L sodium hydroxide aqueous solution, controlling the pH to 11. After reacting at 80℃ for 3 hours, the reaction product is filtered, washed, and dried (dried at 80℃ for 3 hours) to obtain the final product.

[0030] The difference between Comparative Example 1 and Example 1 is that an inorganic substrate is used in this comparative example instead of an equal amount of functional additives.

[0031] The difference between Comparative Example 2 and Example 1 is that magnesium hydroxide (D50 is 2-2.5μm, D90 is 6μm, content ≥99.5%) is used to replace an equal amount of inorganic substrate, and functional additives are prepared using it.

[0032] Comparative Example 3 differs from Example 1 in that hydrochloric acid-acidified sepiolite powder is used instead of an equal amount of inorganic substrate, and functional additives are prepared using it.

[0033] Comparative Example 4 differs from Example 1 in that: in this comparative example, sepiolite powder that has not been acidified with hydrochloric acid is used to replace an equal amount of inorganic substrate, and functional additives are prepared using it.

[0034] Performance testing: The relevant properties of the EPDM rubber material samples prepared in Examples 1-3 and Comparative Examples 1-4 were tested as follows: 1. Flame retardant performance: Tested in accordance with GB / T 10707-2008 standard; 2. UV aging resistance: After UV aging, the mechanical properties of the EPDM rubber material samples were tested according to GB / T 528-2009 standard, and then the mechanical property retention rate was calculated and the surface cracking was observed. The ultraviolet aging test conditions were as follows: a UVA-340 light source (340nm band) was used, the irradiance was 0.49 W / m², and the cycle mode was: 8h of light exposure at 60℃ + 4h of condensation at 50℃, with a total duration of 1500h. Mechanical property retention rate = (mechanical properties after aging / mechanical properties before aging) × 100%; mechanical properties include tensile strength and elongation at break; The specific criteria for classifying crack grades are as follows: Grade 0: No cracks; Grade 1: Microcracks (<10μm); Grade 2: Localized cracks (10-50μm); Grade 3: Obvious cracks (50-200μm); Grade 4: Severe cracks (>200μm).

[0035]

[0036] By comparing and analyzing the experimental data related to Example 1 and Comparative Example 1, it can be seen that the EPDM rubber material prepared by grafting the modifier onto the surface of the inorganic substrate has excellent flame retardant properties and UV aging resistance. This also confirms that the modifier and functional additives prepared in this invention have excellent flame retardant properties and UV aging resistance.

[0037] By comparing and analyzing the experimental data related to Example 1 and Comparative Examples 1-4, it can be seen that the core layer of sepiolite powder and the shell layer of magnesium hydroxide coating in the inorganic substrate have a synergistic relationship in terms of flame retardant properties and UV aging resistance. Simultaneously, due to the high reflectivity and scattering effect of magnesium hydroxide on certain wavelengths of ultraviolet light, the magnesium hydroxide coating also possesses a certain degree of UV aging resistance. Its synergistic effect with the modifier further improves the UV aging resistance of the functional additives and EPDM rubber materials.

[0038] By comparing and analyzing the relevant data in the table, it can be seen that the EPDM rubber material prepared by this invention not only has excellent flame retardant properties but also good resistance to ultraviolet aging. It can effectively reduce the aging phenomenon caused by ultraviolet radiation, thus ensuring its quality while extending its service life to a certain extent. This indicates that the EPDM rubber material for cable accessories and its preparation method provided by this invention have a broader market prospect and are more suitable for widespread application. In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0039] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A EPDM rubber material for cable accessories, characterized in that, It is composed of the following raw materials in parts by weight: 100 parts EPDM rubber, 6-12 parts paraffin oil, 20-30 parts silica, 20-30 parts functional additives, 10-20 parts zinc borate, 10-20 parts calcined clay, 2-4 parts zinc oxide, 1-2 parts cerium oxide, 1-2 parts stearic acid, 2-3 parts antioxidant, 2-3 parts silane coupling agent, 3-6 parts vulcanizing agent, 1-2 parts accelerator and 1-3 parts antioxidant.

2. The EPDM rubber material for cable accessories according to claim 1, characterized in that: The EPDM rubber has a Mooney viscosity ML (1+4, 125℃) ≥ 55, an ethylene content ≥ 55%, and an ENB content ≤ 4.5%.

3. The EPDM rubber material for cable accessories according to claim 1, characterized in that, The preparation method of the functional additive is as follows: Step 1: Under a nitrogen atmosphere, pentaerythritol phosphate is dissolved in toluene at a dosage ratio of 20-50 g / L. UV absorber UV-328 and potassium carbonate are added, and the mixture is reacted at 80-90℃ for 5-8 hours. After the reaction is complete, the product components are filtered while hot, and the toluene in the filtrate is recovered by vacuum distillation. The remaining components are designated as intermediates. The amounts of UV absorber UV-328 and potassium carbonate are 70-75% and 3-5% of the amount of pentaerythritol phosphate, respectively. Step 2: Dissolve the intermediate in toluene at a solid-liquid ratio of 1:10-20. Under nitrogen protection, add 0.5-0.6 times the mass of the intermediate as silane coupling agent KH-550 dropwise with stirring. Then, stir and react at 100-110℃ for 5-8 hours. Cool the resulting reaction solution to room temperature, remove the toluene by vacuum distillation, and then recrystallize and vacuum dry with anhydrous ethanol to obtain the modifier. Step 3: Add the modifier to an ethanol aqueous solution with a volume concentration of 20-30% at a solid-liquid ratio of 1:6-10. Adjust the pH to 4-5 with acetic acid and then ultrasonically disperse for 20-30 minutes. Slowly drop the resulting mixture into an inorganic substrate aqueous dispersion with a volume of 3-5 times the volume and a concentration of 20-50 g / L. After ultrasonic dispersion, keep it at 70-80℃ and stir for 3-5 hours. After cooling the resulting reaction solution to room temperature, filter it, and then wash and vacuum dry it to obtain the functional additive. The inorganic substrate consists of sepiolite and a magnesium hydroxide coating layer on its surface.

4. The EPDM rubber material for cable accessories according to claim 3, characterized in that, The inorganic substrate is prepared by adding hydrochloric acid-acidified sepiolite powder (0.2-0.4 times the mass of magnesium nitrate) to a 0.3-0.6 mol / L magnesium nitrate aqueous solution, dispersing it evenly, and then slowly adding a 2-4 mol / L sodium hydroxide aqueous solution, controlling the pH to 10-11. After reacting at 60-80℃ for 3-5 hours, the reaction product is then filtered, washed, and dried sequentially to obtain the substrate.

5. The EPDM rubber material for cable accessories according to claim 1, characterized in that, The antioxidant is selected from any one of antioxidant RD, antioxidant MB, and antioxidant MBZ.

6. The EPDM rubber material for cable accessories according to claim 1, characterized in that, The silane coupling agent is selected from any one of silane coupling agents KH-570, KH-550, KH-560, and KH-580.

7. The EPDM rubber material for cable accessories according to claim 1, characterized in that, The vulcanizing agent is selected from any one of sulfur, dicumyl peroxide, and benzoyl peroxide.

8. The EPDM rubber material for cable accessories according to claim 1, characterized in that, The accelerator is selected from any one of tetramethylthiuram disulfide, 2-mercaptobenzothiazole, triallyl isocyanurate, and N-cyclohexyl-2-benzothiazole sulfenamide.

9. The EPDM rubber material for cable accessories according to claim 1, characterized in that, The antioxidant is selected from either pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] or tris(2,4-di-tert-butylphenyl) phosphite.

10. A method for preparing EPDM rubber material for cable accessories according to any one of claims 1-9, characterized in that, Includes the following steps: Step 1: Add EPDM rubber, zinc oxide, cerium oxide, stearic acid, antioxidant, and paraffin oil to a mixer and mix at 70-90℃ for 3-5 minutes. Then add silica and silane coupling agent and mix at 80-100℃ for 3-6 minutes. Step 2: After mixing, add functional additives and zinc borate, mix at 80-100℃ for 2-5 minutes, and then discharge the rubber to obtain the compound; transfer the compound to a two-roll mill, pass it through a thin mill 3-5 times, add the remaining raw materials and mix at 40-60℃. Step 3: Transfer the obtained rubber compound into the mold and vulcanize it at 160-170℃ and 10-15MPa for 30-40 minutes.

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