A heat-resistant and insulating EPDM compound

Abstract

The invention discloses a heat-resistant and insulating EPDM rubber compound, comprising the following raw materials in parts by weight: 100-125 parts of EPDM rubber, 8-10 parts of maleic anhydride, 0.5-0.6 parts of initiator, 4-5 parts of zinc oxide, 1-2 parts of stearic acid, 5-6 parts of modified POSS, 4-5 parts of reinforcing agent, 0.5-1 parts of sulfur, 4-4.5 parts of vulcanizing agent, 0.5-0.7 parts of vulcanization accelerator, 6-8 parts of tackifier, 50-60 parts of filler and 40-50 parts of plasticizer. EPDM rubber is resistant to low temperature and has excellent insulation. Modified POSS introduces DOPO structure, maleimide structure and urea structure to enhance the high temperature resistance, flame retardancy and mechanical properties of the rubber compound. The reinforcing agent contains mercaptobenzimidazole structure, aniline structure and carbon nanotubes to improve the metal corrosion resistance, thermal oxidation aging resistance, mechanical properties and wear resistance of the rubber compound.

Description

Technical Field

[0001] The invention relates to the field of ethylene propylene diene monomer (EPDM), and in particular to a heat-resistant and insulating EPDM rubber compound. Background Art

[0002] Ethylene propylene diene monomer (EPDM) is a terpolymer of ethylene, propylene and non-conjugated dienes. The main chain is a saturated carbon chain, the side chain contains unsaturated double bonds, there is no polar substituent group in the molecular chain, the steric hindrance is small, the molecular chain is relatively flexible, and it exhibits excellent resilience, low temperature resistance, water resistance, acid and alkali corrosion resistance and good chemical structure stability. However, EPDM has insufficient mechanical properties, flame retardancy and thermal stability, and its compatibility with inorganic fillers is poor due to its low polarity. A suitable method is needed to solve the current problem. At present, adding POSS to polymers can improve the thermal stability of polymers, but POSS has poor dispersibility in polymers and is prone to phase separation.

[0003] During the use of rubber products such as EPDM, common thermal (light) oxygen aging, ultraviolet aging, and contact medium aging lamp aging phenomena will occur. In order to delay the aging process of rubber products, a certain amount of antioxidants are usually added to them. However, most antioxidants are small molecule additives. They will migrate in the rubber network as the environment changes during the use of rubber, causing a "frost spray" phenomenon, resulting in the inability of small molecule antioxidants to protect the rubber matrix, causing defects in the matrix and affecting its use. It is urgent to develop a suitable modification method to solve the problem of small molecule antioxidants in the use of rubber. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a heat-resistant and insulating EPDM rubber compound.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A heat-resistant and insulating EPDM rubber compound comprises the following raw materials in parts by weight: 100-125 parts of ethylene propylene rubber, 8-10 parts of maleic anhydride, 0.5-0.6 parts of initiator, 4-5 parts of zinc oxide, 1-2 parts of stearic acid, 5-6 parts of modified POSS, 4-5 parts of reinforcing agent, 0.5-1 parts of sulfur, 4-4.5 parts of vulcanizing agent, 0.5-0.7 parts of vulcanization accelerator, 6-8 parts of tackifier, 50-60 parts of filler and 40-50 parts of plasticizer;

[0007] The EPDM rubber is a new type of EPDM rubber synthesized from ethylene, butene and ethylidene norbornene as monomers (see the document "Formula Design of Low-Temperature Resistant and Ultra-Low Compression Set EPDM Rubber" for details);

[0008] The initiator is tert-butyl peroxyneoheptanoate;

[0009] The vulcanizing agent is DCP;

[0010] The vulcanization accelerator is TAIC;

[0011] The tackifier is tert-butyl phenolic resin;

[0012] The filler is white carbon black;

[0013] The plasticizer is paraffin oil 2280;

[0014] The modified POSS is prepared by the following steps:

[0015] Step A1: Add acetone and then vinyltrichlorosilane into a three-necked flask, start stirring, slowly drop distilled water, and then heat under reflux at 50°C for 24-30h, then vacuum filter the resulting reaction solution, wash with acetone, and dry at 50°C to obtain reaction product 1;

[0016] Further, the usage ratio of acetone, vinyltrichlorosilane and distilled water is 65 mL:3.25 g:18 mL;

[0017] During the reaction of step A1, vinyltrichlorosilane is hydrolyzed to generate a reaction product 1, and the structure of the reaction product 1 is shown below:

[0018]

[0019] Step A2: Add reaction product 1, anhydrous tetrahydrofuran and anhydrous pyridine to a flask in sequence, add chlorobenzyltrichlorosilane while stirring in an ice-water bath, after 30 minutes, warm to room temperature, stir to react for 4-5 hours, vacuum filter, wash the filter cake with acetone and water in sequence, and vacuum dry at 80°C to obtain reaction product 2;

[0020] Further, the amount ratio of the reaction product 1, anhydrous tetrahydrofuran, anhydrous pyridine and chlorobenzyltrichlorosilane is 2.36 g: 200 mL: 5 mL: 0.74 g;

[0021] During the reaction of step A2, the reaction product 1 reacts with chlorobenzyltrichlorosilane to generate a cage-type silsesquioxane, namely the reaction product 2. The structure of the reaction product 2 is shown below:

[0022]

[0023] Step A3: Add DOPO, N-(P-maleimidophenyl) isocyanate and DMF into a three-necked flask, introduce nitrogen, heat to 90-110° C., stir to react for 9-10 h, cool to room temperature, recrystallize with distilled water in an ice bath, and filter under reduced pressure to obtain reaction product 3;

[0024] Further, the usage ratio of DOPO, N-(P-maleimidophenyl)isocyanate and DMF is 0.1 mol:0.1 mol:150-160 mL;

[0025] During the reaction of step A3, DOPO undergoes an addition reaction on N-(P-maleimidophenyl)isocyanate to obtain a reaction product 3. The structure of the reaction product 3 is shown below:

[0026]

[0027] Step A4: adding the reaction product 3, 4-amino-3-methylphenol and methanol into a flask, stirring and reacting at room temperature for 3-4 hours to obtain the reaction product 4; adding the reaction product 4, potassium carbonate, potassium iodide, DMF and THF into a flask, stirring at room temperature for 1-1.5 hours, and then adding the reaction product 2, stirring and reacting at 70° C. for 3-4 hours to obtain the modified POSS;

[0028] Further, the usage ratio of reaction product 3, 4-amino-3-methylphenol and methanol is 0.1 mol: 0.1 mol: 200-220 mL; the usage ratio of reaction product 2, reaction product 4, potassium carbonate, potassium iodide, DMF and THF is 2 g: 0.2-0.3 g: 4.6 g: 1.6 g: 30 mL: 15 mL;

[0029] During the reaction of step A4, the isocyanate group in the reaction product 2 reacts rapidly with the amino group in 4-amino-3-methylphenol to generate a reaction product 3 containing a stable urea structure; the benzyl chloride in the reaction product 2 reacts with the phenolic hydroxyl group in the reaction product 4 to undergo a dehydrochlorination reaction to obtain a modified POSS. The modified POSS contains a DOPO structure, a maleimide structure, urea and vinyl POSS, etc. During the high-temperature vulcanization process of the rubber compound, the vinyl POSS is grafted with EPDM, and the dispersibility of the modified POSS is improved; the DOPO structure and a high content of nitrogen make the modified POSS have good halogen-free flame retardant properties; the structural stability of urea is high, which improves the structural stability of the modified POSS.

[0030] The structure of modified POSS is shown below:

[0031]

[0032] The preparation of the enhancer comprises the following steps:

[0033] Step B1: Add 2,4-dinitro-N-(4-nitrophenyl)aniline to ethanol, start stirring, introduce nitrogen, then add Pd / C and hydrazine, and stir at room temperature for 7-8 hours to obtain reaction product a;

[0034] Further, the usage ratio of 2,4-dinitro-N-(4-nitrophenyl)aniline, ethanol, Pd / C and hydrazine is 0.1 mol: 90-100 mL: 0.001-0.0015 g: 0.1 mol;

[0035] During the reaction of step B1, the nitro group of 2,4-dinitro-N-(4-nitrophenyl)aniline is reduced to an amino group to obtain a reaction product a. The structure of the reaction product a is shown below:

[0036]

[0037] Step B2: Add the reaction product a, carbon disulfide and potassium hydroxide into ethanol, start stirring, then add 1-n-butyl-3-methylimidazolium trifluoromethanesulfonate, and stir at 35-40° C. for 24 hours to obtain the reaction product b;

[0038] Further, the reaction product a, carbon disulfide, potassium hydroxide, ethanol and 1-n-butyl-3-methylimidazolium trifluoromethanesulfonate are 0.1mol: 0.1-0.15mol: 0.002-0.0025mol: 150-170mL: 0.001-0.0012mol;

[0039] During the reaction of step B2, under the catalysis of 1-n-butyl-3-methylimidazolium trifluoromethanesulfonate, the reaction product a reacts with carbon disulfide to generate a reaction product b having a mercaptoimidazole structure. The structure of the reaction product b is shown below:

[0040]

[0041] Step B3: After ball milling the short multi-walled carbon nanotubes for 2-3 hours, add them to the mixed acid, start stirring, reflux at 100-120° C. for 1.5-2.5 hours, dilute, filter, wash, and dry in an oven at 110° C. for 6-8 hours to obtain carboxyl-modified carbon nanotubes;

[0042] Furthermore, the dosage ratio of short multi-walled carbon nanotubes and mixed acid is 10-15 g: 100-120 mL; the mixed acid is prepared by mixing concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 3:1, and the mass fractions of concentrated sulfuric acid and concentrated nitric acid are both 98%;

[0043] During the reaction of step B3, the carbon nanotubes are treated with mixed acid to obtain carbon nanotubes with open ends and modified with carboxyl groups.

[0044] Step B4: Add the reaction product b and ethanol into a beaker, stir for 25-35 minutes, then add the carboxyl-modified carbon nanotubes into the beaker, seal the beaker with a sealing film, and then place the beaker in an ultrasonic treatment for 24-26 hours to obtain an enhancer;

[0045] Further, the amount ratio of the reaction product b, the carboxyl-modified carbon nanotubes, and ethanol is 0.01 mol: 10 g: 300-350 mL;

[0046] During the reaction of step B4, the hollow tubular structure of the carboxyl-modified carbon nanotubes can provide a large specific surface area to load the reaction product b, thereby firmly loading the reaction product b on the surface of the carbon nanotubes to obtain a reinforcing agent, avoiding the migration of the small molecule reaction product b from the rubber network, and effectively inhibiting the "blooming" phenomenon. The reinforcing agent contains a mercaptobenzimidazole structure, an aniline structure, and a carbon nanotube structure. The mercaptobenzimidazole structure has excellent thermal oxidative aging protection performance, and will not pollute the rubber after being exposed to light and heat, so that the reinforcing agent can produce non-polluting thermal oxidative aging resistance. The benzimidazole structure can also form a stable complex with heavy metals, so that the heavy metals do not catalyze the oxidation of the rubber; the active amino group in the aniline structure has a high reactivity, giving the reinforcing agent crosslinkability; the carbon nanotubes have good mechanical properties and hardness, so that the reinforcing agent has an excellent reinforcing effect.

[0047] Beneficial effects of the invention: The invention discloses a heat-resistant and insulating EPDM rubber compound, comprising EPDM, maleic anhydride, an initiator, zinc oxide, stearic acid, modified POSS, a reinforcing agent, sulfur, a vulcanizing agent, a vulcanization accelerator, a tackifier, a filler and a plasticizer. EPDM is a new type of EPDM synthesized by replacing propylene with butene. The butene molecular chain is relatively long and it is difficult to form a crystalline segment at low temperature, so as to maintain the flexibility of the rubber molecular chain and further enhance the low temperature resistance of the rubber compound. EPDM and maleic anhydride are grafted under the initiation of the initiator tert-butyl peroxy neoheptanoate to improve the polarity of EPDM and enhance the compatibility of EPDM with inorganic fillers. The synthesized modified POSS contains DOPO structure, maleimide structure, urea and vinyl POSS, etc. During the high-temperature vulcanization process of the rubber compound, vinyl POSS is grafted with EPDM, and the dispersibility of the modified POSS is improved, which significantly improves the high-temperature resistance of the rubber compound. The DOPO structure and high nitrogen content make the modified POSS have good halogen-free flame retardant properties. Phosphorus-containing compounds are produced during the pyrolysis of the DOPO structure, which promotes the formation of a dense carbon layer, heat insulation and oxygen isolation. The nitrogen element burns to produce non-flammable gases such as ammonia, which dilutes the combustible gas and improves the flame retardant properties of the rubber compound. The urea structure has a high structural stability, which improves the structural stability of the modified POSS and enables the modified POSS to play a stable role in the rubber compound. Maleimide and vinyl POSS have strong rigidity, which improves the mechanical properties of the rubber compound.

[0048] The reinforcing agent contains mercaptobenzimidazole structure, aniline structure and carbon nanotube structure. The reaction product b is loaded on the carbon nanotube to prevent the migration of the small molecule reaction product b from the rubber network and inhibit the "blooming" phenomenon; the mercaptobenzimidazole structure has excellent thermal oxidation aging protection performance, will not cause pollution to the rubber after being exposed to light and heat, and can reduce the discoloration of the mixed rubber during vulcanization. The benzimidazole structure can also form a stable complex with heavy metals to prevent the heavy metals from catalyzing the oxidation of the mixed rubber when the mixed rubber is used on the metal surface, thereby avoiding the metal from corroding the mixed rubber and improving the metal corrosion resistance of the mixed rubber; the active amino group in the aniline structure has a high reactivity, so that the reinforcing agent can be cross-linked with the maleic anhydride grafted with EPDM, increasing the dispersibility of the reinforcing agent in the mixed rubber; the carbon nanotubes have good mechanical properties and hardness, and with the uniform dispersion of the reinforcing agent in the mixed rubber, the mechanical properties and wear resistance of the mixed rubber are improved. DETAILED DESCRIPTION

[0049] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Example 1

[0050] A modified POSS, the preparation of which comprises the following steps:

[0051] Step A1: Add acetone and then vinyltrichlorosilane to a three-necked flask, start stirring, slowly drop distilled water, and then heat under reflux at 50°C for 24h, then vacuum filter the resulting reaction solution, wash with acetone, and dry at 50°C to obtain reaction product 1; the dosage ratio of acetone, vinyltrichlorosilane and distilled water is 65mL:3.25g:18mL;

[0052] Step A2: Add reaction product 1, anhydrous tetrahydrofuran and anhydrous pyridine to a flask in sequence, add chlorobenzyltrichlorosilane while stirring in an ice-water bath, after 30 minutes, warm to room temperature, stir and react for 4 hours, vacuum filter, wash the filter cake with acetone and water in sequence, and dry in vacuum at 80°C to obtain reaction product 2; the amount ratio of reaction product 1, anhydrous tetrahydrofuran, anhydrous pyridine and chlorobenzyltrichlorosilane is 2.36g:200mL:5mL:0.74g;

[0053] Step A3: DOPO, N-(P-maleimidophenyl)isocyanate and DMF were added to a three-necked flask, nitrogen was introduced, the temperature was raised to 90°C, the reaction was stirred for 9 hours, the mixture was cooled to room temperature, recrystallized with distilled water in an ice bath, and filtered under reduced pressure to obtain a reaction product 3; the amount ratio of DOPO, N-(P-maleimidophenyl)isocyanate and DMF was 0.1 mol: 0.1 mol: 150 mL;

[0054] Step A4: Add reaction product 3, 4-amino-3-methylphenol and methanol to a flask, stir and react at room temperature for 3 hours to obtain reaction product 4; add reaction product 4, potassium carbonate, potassium iodide, DMF and THF to a flask, stir at room temperature for 1 hour, then add reaction product 2, stir and react at 70°C for 3 hours to obtain modified POSS; the amount ratio of reaction product 3, 4-amino-3-methylphenol and methanol is 0.1 mol: 0.1 mol: 200 mL; the amount ratio of reaction product 2, reaction product 4, potassium carbonate, potassium iodide, DMF and THF is 2 g: 0.2 g: 4.6 g: 1.6 g: 30 mL: 15 mL. Example 2

[0055] A modified POSS, the preparation of which comprises the following steps:

[0056] Step A1: Add acetone and then vinyltrichlorosilane to a three-necked flask, start stirring, slowly drop distilled water, and then heat under reflux at 50°C for 27h, then vacuum filter the resulting reaction solution, wash with acetone, and dry at 50°C to obtain reaction product 1; the dosage ratio of acetone, vinyltrichlorosilane and distilled water is 65mL:3.25g:18mL;

[0057] Step A2: Add reaction product 1, anhydrous tetrahydrofuran and anhydrous pyridine to a flask in sequence, add chlorobenzyltrichlorosilane while stirring in an ice-water bath, after 30 minutes, warm to room temperature, stir and react for 4.5 hours, vacuum filter, wash the filter cake with acetone and water in sequence, and dry in vacuum at 80°C to obtain reaction product 2; the amount ratio of reaction product 1, anhydrous tetrahydrofuran, anhydrous pyridine and chlorobenzyltrichlorosilane is 2.36g:200mL:5mL:0.74g;

[0058] Step A3: DOPO, N-(P-maleimidophenyl)isocyanate and DMF were added to a three-necked flask, nitrogen was introduced, the temperature was raised to 100°C, the reaction was stirred for 9.5 hours, the reaction was cooled to room temperature, the reaction was recrystallized with distilled water in an ice bath, and the reaction product 3 was obtained by vacuum filtration; the amount ratio of DOPO, N-(P-maleimidophenyl)isocyanate and DMF was 0.1 mol: 0.1 mol: 155 mL;

[0059] Step A4: Add reaction product 3, 4-amino-3-methylphenol and methanol to a flask, stir and react at room temperature for 3.5 hours to obtain reaction product 4; add reaction product 4, potassium carbonate, potassium iodide, DMF and THF to a flask, stir at room temperature for 1.2 hours, then add reaction product 2, stir and react at 70°C for 3.5 hours to obtain modified POSS; the amount ratio of reaction product 3, 4-amino-3-methylphenol and methanol is 0.1 mol: 0.1 mol: 210 mL; the amount ratio of reaction product 2, reaction product 4, potassium carbonate, potassium iodide, DMF and THF is 2 g: 0.25 g: 4.6 g: 1.6 g: 30 mL: 15 mL. Example 3

[0060] A modified POSS, the preparation of which comprises the following steps:

[0061] Step A1: Add acetone and then vinyltrichlorosilane to a three-necked flask, start stirring, slowly drop distilled water, and then heat under reflux at 50°C for 30 hours, then vacuum filter the resulting reaction solution, wash with acetone, and dry at 50°C to obtain reaction product 1; the amount ratio of acetone, vinyltrichlorosilane and distilled water is 65mL:3.25g:18mL;

[0062] Step A2: Add reaction product 1, anhydrous tetrahydrofuran and anhydrous pyridine to a flask in sequence, add chlorobenzyltrichlorosilane while stirring in an ice-water bath, after 30 minutes, warm to room temperature, stir and react for 5 hours, vacuum filter, wash the filter cake with acetone and water in sequence, and dry in vacuum at 80°C to obtain reaction product 2; the amount ratio of reaction product 1, anhydrous tetrahydrofuran, anhydrous pyridine and chlorobenzyltrichlorosilane is 2.36g:200mL:5mL:0.74g;

[0063] Step A3: DOPO, N-(P-maleimidophenyl)isocyanate and DMF were added to a three-necked flask, nitrogen was introduced, the temperature was raised to 110°C, the reaction was stirred for 10 hours, the mixture was cooled to room temperature, recrystallized with distilled water in an ice bath, and filtered under reduced pressure to obtain a reaction product 3; the amount ratio of DOPO, N-(P-maleimidophenyl)isocyanate and DMF was 0.1 mol: 0.1 mol: 160 mL;

[0064] Step A4: Add reaction product 3, 4-amino-3-methylphenol and methanol to a flask, stir and react at room temperature for 4 hours to obtain reaction product 4; add reaction product 4, potassium carbonate, potassium iodide, DMF and THF to a flask, stir at room temperature for 1.5 hours, then add reaction product 2, stir and react at 70°C for 4 hours to obtain modified POSS; the amount ratio of reaction product 3, 4-amino-3-methylphenol and methanol is 0.1 mol: 0.1 mol: 220 mL; the amount ratio of reaction product 2, reaction product 4, potassium carbonate, potassium iodide, DMF and THF is 2 g: 0.3 g: 4.6 g: 1.6 g: 30 mL: 15 mL. Example 4

[0065] A reinforcing agent, the preparation of which comprises the following steps:

[0066] Step B1: Add 2,4-dinitro-N-(4-nitrophenyl)aniline to ethanol, start stirring, introduce nitrogen, then add Pd / C and hydrazine, and stir the reaction at room temperature for 7 hours to obtain reaction product a; the amount ratio of 2,4-dinitro-N-(4-nitrophenyl)aniline, ethanol, Pd / C and hydrazine is 0.1 mol:90 mL:0.001 g:0.1 mol;

[0067] Step B2: Add the reaction product a, carbon disulfide and potassium hydroxide to ethanol, start stirring, then add 1-n-butyl-3-methylimidazolium trifluoromethanesulfonate, and stir the reaction at 35°C for 24 hours to obtain the reaction product b; the reaction product a, carbon disulfide, potassium hydroxide, ethanol and 1-n-butyl-3-methylimidazolium trifluoromethanesulfonate are 0.1 mol: 0.1 mol: 0.002 mol: 150 mL: 0.001 mol;

[0068] Step B3: After ball milling the short multi-walled carbon nanotubes for 2 hours, add them to the mixed acid, start stirring, reflux at 100°C for 1.5 hours, dilute, filter, wash, and dry in an oven at 110°C for 6 hours to obtain carboxyl-modified carbon nanotubes; the dosage ratio of the short multi-walled carbon nanotubes to the mixed acid is 10g:100mL; the mixed acid is prepared by mixing concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 3:1, and the mass fractions of the concentrated sulfuric acid and concentrated nitric acid are both 98%;

[0069] Step B4: Add the reaction product b and ethanol into a beaker, stir for 25 minutes, then add the above-mentioned carboxyl-modified carbon nanotubes into the beaker, seal the beaker with a sealing film, and then place the beaker in an ultrasonic treatment for 24 hours to obtain an enhancer; the amount ratio of the reaction product b, carboxyl-modified carbon nanotubes, and ethanol is 0.01 mol: 10 g: 300 mL. Example 5

[0070] A reinforcing agent, the preparation of which comprises the following steps:

[0071] Step B1: Add 2,4-dinitro-N-(4-nitrophenyl)aniline to ethanol, start stirring, introduce nitrogen, then add Pd / C and hydrazine, and stir the reaction at room temperature for 7.5 hours to obtain reaction product a; the amount ratio of 2,4-dinitro-N-(4-nitrophenyl)aniline, ethanol, Pd / C and hydrazine is 0.1 mol:95 mL:0.0012 g:0.1 mol;

[0072] Step B2: Add the reaction product a, carbon disulfide and potassium hydroxide to ethanol, start stirring, then add 1-n-butyl-3-methylimidazolium trifluoromethanesulfonate, and stir the reaction at 35°C for 24 hours to obtain the reaction product b; the reaction product a, carbon disulfide, potassium hydroxide, ethanol and 1-n-butyl-3-methylimidazolium trifluoromethanesulfonate are 0.1 mol: 0.12 mol: 0.0022 mol: 160 mL: 0.0011 mol;

[0073] Step B3: After ball milling the short multi-walled carbon nanotubes for 2-3 hours, add them to the mixed acid, start stirring, reflux at 110°C for 2 hours, dilute, filter, wash, and dry in an oven at 110°C for 7 hours to obtain carboxyl-modified carbon nanotubes; the dosage ratio of the short multi-walled carbon nanotubes to the mixed acid is 12g:110mL; the mixed acid is prepared by mixing concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 3:1, and the mass fractions of the concentrated sulfuric acid and concentrated nitric acid are both 98%;

[0074] Step B4: Add the reaction product b and ethanol into a beaker, stir for 30 minutes, then add the above-mentioned carboxyl-modified carbon nanotubes into the beaker, seal the beaker with a sealing film, and then place the beaker in an ultrasonic treatment for 25 hours to obtain an enhancer; the amount ratio of the reaction product b, carboxyl-modified carbon nanotubes, and ethanol is 0.01 mol: 10 g: 325 mL. Example 6

[0075] A reinforcing agent, the preparation of which comprises the following steps:

[0076] Step B1: Add 2,4-dinitro-N-(4-nitrophenyl)aniline to ethanol, start stirring, introduce nitrogen, then add Pd / C and hydrazine, and stir at room temperature for 8 hours to obtain reaction product a; the amount ratio of 2,4-dinitro-N-(4-nitrophenyl)aniline, ethanol, Pd / C and hydrazine is 0.1 mol: 100 mL: 0.0015 g: 0.1 mol;

[0077] Step B2: Add the reaction product a, carbon disulfide and potassium hydroxide to ethanol, start stirring, then add 1-n-butyl-3-methylimidazolium trifluoromethanesulfonate, and stir the reaction at 40°C for 24 hours to obtain the reaction product b; the reaction product a, carbon disulfide, potassium hydroxide, ethanol and 1-n-butyl-3-methylimidazolium trifluoromethanesulfonate are 0.1 mol: 0.15 mol: 0.0025 mol: 170 mL: 0.0012 mol;

[0078] Step B3: After ball milling the short multi-walled carbon nanotubes for 2-3 hours, add them to the mixed acid, start stirring, reflux at 120°C for 2.5 hours, dilute, filter, wash, and dry in an oven at 110°C for 8 hours to obtain carboxyl-modified carbon nanotubes; the dosage ratio of the short multi-walled carbon nanotubes to the mixed acid is 15g:120mL; the mixed acid is prepared by mixing concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 3:1, and the mass fractions of the concentrated sulfuric acid and concentrated nitric acid are both 98%;

[0079] Step B4: Add the reaction product b and ethanol into a beaker, stir for 35 minutes, then add the above-mentioned carboxyl-modified carbon nanotubes into the beaker, seal the beaker with a sealing film, and then place the beaker in an ultrasonic treatment for 26 hours to obtain an enhancer; the amount ratio of the reaction product b, ethanol, and carboxyl-modified carbon nanotubes is 0.01 mol: 350 mL: 10 g. Example 7

[0080] A heat-resistant and insulating EPDM rubber compound comprises the following raw materials in parts by weight: 100 parts of ethylene propylene rubber, 8 parts of maleic anhydride, 0.5 parts of initiator, 4 parts of zinc oxide, 1 part of stearic acid, 5 parts of modified POSS, 4 parts of reinforcing agent, 0.5 parts of sulfur, 4 parts of vulcanizing agent, 0.5 parts of vulcanization accelerator, 6 parts of tackifier, 50 parts of filler and 40 parts of plasticizer; the ethylene propylene rubber is a new type of EPDM synthesized from ethylene, butylene and ethylidene norbornene as monomers; the initiator is tert-butyl peroxyneoheptanoate; the vulcanizing agent is DCP; the vulcanization accelerator is TAIC; the tackifier is tert-butyl phenolic resin; the filler is white carbon black; the plasticizer is paraffin oil 2280;

[0081] The preparation of the heat-resistant and insulating EPDM rubber compound comprises the following steps:

[0082] Step S1: adding EPDM rubber, maleic anhydride and initiator into a torque rheometer, mixing for 13 min at 170° C. and a rotation speed of 60 r / min, extracting with acetone, and vacuum drying at 60° C. to obtain modified EPDM rubber;

[0083] Step S2: Add modified EPDM rubber, zinc oxide, stearic acid, modified POSS obtained in Example 1, reinforcing agent, tackifier, filler and plasticizer into a torque rheometer, mix for 20 min at 150 ° C and a rotation speed of 50 r / min, add sulfur, vulcanizing agent and vulcanization accelerator, continue mixing for 15 min, place on the vulcanizing agent, and vulcanize for 15 min at a pressure of 15 MPa and a temperature of 180 ° C to obtain a heat-resistant and insulating EPDM compound. Example 8

[0084] A heat-resistant and insulating EPDM rubber compound comprises the following raw materials in parts by weight: 110 parts of ethylene propylene rubber, 9 parts of maleic anhydride, 0.5 parts of initiator, 4.5 parts of zinc oxide, 1.5 parts of stearic acid, 5.5 parts of modified POSS, 4.5 parts of reinforcing agent, 0.7 parts of sulfur, 4.2 parts of vulcanizing agent, 0.6 parts of vulcanization accelerator, 7 parts of tackifier, 55 parts of filler and 45 parts of plasticizer; the ethylene propylene rubber is a new type of EPDM synthesized from ethylene, butylene and ethylidene norbornene as monomers; the initiator is tert-butyl peroxyneoheptanoate; the vulcanizing agent is DCP; the vulcanization accelerator is TAIC; the tackifier is tert-butyl phenolic resin; the filler is white carbon black; the plasticizer is paraffin oil 2280;

[0085] The preparation of the heat-resistant and insulating EPDM rubber compound comprises the following steps:

[0086] Step S1: adding EPDM rubber, maleic anhydride and initiator into a torque rheometer, mixing for 14 min at 175° C. and a rotation speed of 60 r / min, extracting with acetone, and vacuum drying at 60° C. to obtain modified EPDM rubber;

[0087] Step S2: Add modified EPDM rubber, zinc oxide, stearic acid, modified POSS obtained in Example 2, reinforcing agent obtained in Example 5, tackifier, filler and plasticizer into a torque rheometer, mix for 25 min at 155 ° C and a rotation speed of 50 r / min, add sulfur, vulcanizing agent and vulcanization accelerator, continue mixing for 20 min, place on the vulcanizing agent, and vulcanize for 15 min at a pressure of 15 MPa and a temperature of 185 ° C to obtain a heat-resistant and insulating EPDM compound. Example 9

[0088] A heat-resistant and insulating EPDM rubber compound comprises the following raw materials in parts by weight: 125 parts of ethylene propylene rubber, 10 parts of maleic anhydride, 0.6 parts of initiator, 5 parts of zinc oxide, 2 parts of stearic acid, 6 parts of modified POSS, 5 parts of reinforcing agent, 1 part of sulfur, 4.5 parts of vulcanizing agent, 0.7 parts of vulcanization accelerator, 8 parts of tackifier, 60 parts of filler and 50 parts of plasticizer; the ethylene propylene rubber is a new type of EPDM synthesized from ethylene, butylene and ethylidene norbornene as monomers; the initiator is tert-butyl peroxyneoheptanoate; the vulcanizing agent is DCP; the vulcanization accelerator is TAIC; the tackifier is tert-butyl phenolic resin; the filler is white carbon black; the plasticizer is paraffin oil 2280;

[0089] The preparation of the heat-resistant and insulating EPDM rubber compound comprises the following steps:

[0090] Step S1: adding EPDM rubber, maleic anhydride and initiator into a torque rheometer, mixing for 15 min at 180° C. and a rotation speed of 60 r / min, extracting with acetone, and vacuum drying at 60° C. to obtain modified EPDM rubber;

[0091] Step S2: Add modified EPDM rubber, zinc oxide, stearic acid, modified POSS obtained in Example 3, reinforcing agent obtained in Example 6, tackifier, filler and plasticizer into a torque rheometer, mix for 30 minutes at 160°C and a rotation speed of 50r / min, add sulfur, vulcanizing agent and vulcanization accelerator, continue mixing for 25 minutes, place on the vulcanizing agent, and vulcanize for 15 minutes at a pressure of 15MPa and a temperature of 190°C to obtain a heat-resistant and insulating EPDM compound.

[0092] Comparative Example 1

[0093] This comparative example is a commercially available EPDM rubber compound.

[0094] Comparative Example 2

[0095] Compared with Example 9, the modified POSS is replaced with octavinyl POSS, and the rest is exactly the same as Example 9 to obtain a heat-resistant and insulating EPDM compound rubber.

[0096] Comparative Example 3

[0097] Compared with Example 9, the reinforcing agent is replaced with carbon nanotubes and the reaction product b is added to the formula independently, and the rest is exactly the same as Example 9 to obtain a heat-resistant and insulating EPDM compound rubber.

[0098] The heat-resistant and insulating EPDM rubber compound prepared by the present invention is further tested for its effect, and the test results are as follows.

[0099] In order to test the heat-resistant and insulating EPDM rubber compound prepared by the present invention, the mechanical properties were measured according to GB / T528-2009; the hot air aging test was carried out according to GBT 3512-2014; the metal corrosion resistance test was carried out according to QC / T 639-2004, and the standard classification was grade 1 (not turned into black), grade 2 (mild tempering color), grade 3 (heavy tempering color), and grade 4 (turned into black); the flame retardant performance was measured according to GB10707-2008, and the hardness was measured according to GB531.1-2008; the blooming test method was to place the rubber compound under the conditions of 70° C. and 95% humidity for 500 hours to observe whether there was blooming; the results are shown in Table 1.

[0100] Table 1:

[0101]

[0102] According to the data in Table 1, compared with Example 1, Example 7, Example 8 and Example 9, it can be seen that the heat-resistant and insulating EPDM rubber compound prepared by the present invention has excellent mechanical properties, wear resistance, thermal oxidative aging resistance, metal corrosion resistance and flame retardancy compared with commercially available EPDM rubber compounds; compared with Example 2, Example 9 shows that the use of modified POSS to introduce DOPO structure, maleimide structure and urea structure enhances the flame retardancy and mechanical properties of the rubber compound; compared with Example 3, Example 9 shows that the use of a reinforcing agent to introduce a mercaptobenzimidazole structure, an aniline structure and carbon nanotubes, and after the reaction product b is loaded on the carbon nanotubes, the "blooming" phenomenon can be suppressed, and the metal corrosion resistance, thermal oxidative aging resistance, mechanical properties and wear resistance of the rubber compound are effectively improved.

[0103] The above contents are merely examples and explanations of the concept of the present invention. The technicians in this technical field may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the concept of the invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

Claims

1. A heat-resistant and insulating EPDM rubber compound, characterized in that: The invention comprises the following raw materials in parts by weight: 100-125 parts of EPDM rubber, 8-10 parts of maleic anhydride, 0.5-0.6 parts of initiator, 4-5 parts of zinc oxide, 1-2 parts of stearic acid, 5-6 parts of modified POSS, 4-5 parts of reinforcing agent, 0.5-1 parts of sulfur, 4-4.5 parts of vulcanizing agent, 0.5-0.7 parts of vulcanization accelerator, 6-8 parts of tackifier, 50-60 parts of filler and 40-50 parts of plasticizer; The modified POSS is prepared by the following steps: Step A1: Add acetone and then vinyltrichlorosilane into a three-necked flask, start stirring, slowly drop distilled water, and then heat under reflux at 50°C for 24-30h, then vacuum filter the resulting reaction solution, wash with acetone, and dry at 50°C to obtain reaction product 1; Step A2: Add reaction product 1, anhydrous tetrahydrofuran and anhydrous pyridine to a flask in sequence, add chlorobenzyltrichlorosilane while stirring in an ice-water bath, after 30 minutes, warm to room temperature, stir to react for 4-5 hours, vacuum filter, wash the filter cake with acetone and water in sequence, and vacuum dry at 80°C to obtain reaction product 2; Step A3: Add DOPO, N-(P-maleimidophenyl) isocyanate and DMF into a three-necked flask, introduce nitrogen, heat to 90-110° C., stir to react for 9-10 h, cool to room temperature, recrystallize with distilled water in an ice bath, and filter under reduced pressure to obtain reaction product 3; Step A4: adding the reaction product 3, 4-amino-3-methylphenol and methanol into a flask, stirring and reacting at room temperature for 3-4 hours to obtain the reaction product 4; adding the reaction product 4, potassium carbonate, potassium iodide, DMF and THF into a flask, stirring at room temperature for 1-1.5 hours, and then adding the reaction product 2, stirring and reacting at 70° C. for 3-4 hours to obtain the modified POSS; In step A2, the amount ratio of reaction product 1, anhydrous tetrahydrofuran, anhydrous pyridine and chlorobenzyltrichlorosilane is 2.36 g: 200 mL: 5 mL: 0.74 g; In step A3, the ratio of DOPO, N-(P-maleimidophenyl)isocyanate and DMF is 0.1 mol: 0.1 mol: 150-160 mL; In step A4, the amount ratio of reaction product 3, 4-amino-3-methylphenol and methanol is 0.1 mol: 0.1 mol: 200-220 mL; the amount ratio of reaction product 2, reaction product 4, potassium carbonate, potassium iodide, DMF and THF is 2 g: 0.2-0.3 g: 4.6 g: 1.6 g: 30 mL: 15 mL; The EPDM rubber is a EPDM rubber synthesized from ethylene, butene and ethylidene norbornene as monomers; the initiator is tert-butyl peroxyneoheptanoate; the vulcanizing agent is DCP; the vulcanization accelerator is TAIC; the tackifier is tert-butyl phenolic resin; the filler is white carbon black; and the plasticizer is paraffin oil 2280; The preparation of the enhancer comprises the following steps: Step B1: Add 2,4-dinitro-N-(4-nitrophenyl)aniline to ethanol, start stirring, introduce nitrogen, then add Pd / C and hydrazine, and stir at room temperature for 7-8 hours to obtain reaction product a; Step B2: Add the reaction product a, carbon disulfide and potassium hydroxide into ethanol, start stirring, then add 1-n-butyl-3-methylimidazolium trifluoromethanesulfonate, and stir at 35-40° C. for 24 hours to obtain the reaction product b; Step B3: After ball milling the short multi-walled carbon nanotubes for 2-3 hours, add them to the mixed acid, start stirring, reflux at 100-120° C. for 1.5-2.5 hours, dilute, filter, wash, and dry in an oven at 110° C. for 6-8 hours to obtain carboxyl-modified carbon nanotubes; Step B4: Add the reaction product b and ethanol into a beaker, stir for 25-35 minutes, then add the carboxyl-modified carbon nanotubes into the beaker, seal the beaker with a sealing film, and then place the beaker in an ultrasonic treatment for 24-26 hours to obtain an enhancer; In step B1, the ratio of 2,4-dinitro-N-(4-nitrophenyl)aniline, ethanol, Pd / C and hydrazine is 0.1 mol: 90-100 mL: 0.001-0.0015 g: 0.1 mol; In step B2, the reaction product a, carbon disulfide, potassium hydroxide, ethanol and 1-n-butyl-3-methylimidazolium trifluoromethanesulfonate are 0.1 mol: 0.1-0.15 mol: 0.002-0.0025 mol: 150-170 mL: 0.001-0.0012 mol.

2. A heat-resistant and insulating EPDM rubber compound according to claim 1, characterized in that: In step A1, the usage ratio of acetone, vinyltrichlorosilane and distilled water is 65 mL:3.25 g:18 mL.

3. The heat-resistant and insulating EPDM rubber compound according to claim 1, characterized in that: In step B3, the amount ratio of short multi-walled carbon nanotubes and mixed acid is 10-15g:100-120mL; the mixed acid is prepared by mixing concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 3:1, and the mass fractions of concentrated sulfuric acid and concentrated nitric acid are both 98%; in step B4, the amount ratio of reaction product b, carboxyl-modified carbon nanotubes, and ethanol is 0.01mol:10g:300-350mL.

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