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CN-122011607-A - Rare earth modified EPDM rubber with low compression set and preparation method and application thereof

CN122011607ACN 122011607 ACN122011607 ACN 122011607ACN-122011607-A

Abstract

The application provides rare earth modified EPDM rubber with low compression set, a preparation method and application thereof, comprising EPDM, rare earth core-shell particles, IL, sulfur, phenolic resin cross-linking agent, BMI, accelerator, anti-aging agent, paraffin oil, carbon black, stearic acid and processing aid. The application adopts a one-step in-situ modification-masterbatch dilution-low temperature mixing-common two-stage vulcanization process to realize uniform dispersion of rare earth particles in an EPDM matrix, avoid agglomeration and frosting, lead CS value to be 5.8% -7.8% under the compression condition of 100 ℃ multiplied by 70h/25%, be far lower than the prior 25% -35% and meet the requirements of less than or equal to 10% of high-end scenes, lead CS retention rate to be more than or equal to 90% after aging at 150 ℃ multiplied by 168h, have no rebound phenomenon, and have outstanding aspects of balanced and stable mechanical properties, high and low temperature resistance, ageing resistance, processing and use stability and the like, strong industrial feasibility, low process energy consumption and large-scale production, expand the application of the composition in the field of high-end sealing and meet the severe use requirements of scenes such as fuel cells, LNG equipment, spacecrafts and the like.

Inventors

  • WU YINCAI
  • ZHU YANMIN
  • WANG XINKUN
  • ZHENG HUAAN
  • SONG LIJUN
  • HUANG YAN
  • LIN FENGLONG
  • LI JINJIE
  • WANG SHENGLONG
  • LIAN HAIJIANG
  • XU WEIEN

Assignees

  • 厦门麦丰密封件有限公司

Dates

Publication Date
20260512
Application Date
20260414

Claims (10)

  1. 1. The rare earth modified EPDM rubber with low compression set is characterized by comprising, by weight, 100 parts of EPDM, 1.5-4.0 parts of rare earth oxide core-shell particles, 0.3-1.2 parts of ionic liquid monomers, 0.3-0.8 parts of sulfur, 1.0-2.5 parts of phenolic resin cross-linking agents, 0.5-1.5 parts of bismaleimide, 0.8-1.5 parts of accelerators MBT, 0.3-0.6 parts of accelerators TBzTD, 1.0-2.0 parts of antioxidants 445, 15-25 parts of paraffin oil, 40-60 parts of carbon black, 1.0 parts of stearic acid and 2.0 parts of processing aids WB 222; The ionic liquid monomer is selected from 1-vinyl-3-methylimidazole bis (trifluoromethanesulfonyl) imide salt or 1-carboxypropyl-3-methylimidazole bis (trifluoromethanesulfonyl) imide salt; The rare earth oxide core-shell particles are obtained by carrying out in-situ surface modification on rare earth oxide by triethoxysilane containing epoxy groups and ionic liquid monomers, and the rare earth oxide is CeO 2 and La 2 O 3 .
  2. 2. The rare earth modified EPDM rubber of claim 1, wherein the ENB content of the EPDM is 4.5 wt.% and the mooney viscosity ML (1+4) is 125 ℃ 55±5.
  3. 3. The low compression set rare earth modified EPDM rubber of claim 1, wherein the ionic liquid monomer is present in an amount of 0.3 times the total molar amount of rare earth oxide, and the carbon black is at least one of N550 and N330.
  4. 4. The preparation method of the rare earth modified EPDM rubber with low compression set is characterized by comprising the following steps: S1, preparing master batch, namely adding 30phr of EPDM, rare earth oxide core-shell particles, ionic liquid monomer, anti-aging agent 445 and stearic acid into an internal mixer, setting the temperature to be 75-85 ℃ and the rotating speed to be 55-65rpm, mixing for 3-5min, and discharging the master batch; S2, diluting and mixing, namely adding the rest 70phr of EPDM, carbon black, paraffin oil, phenolic resin cross-linking agent, BMI, sulfur, accelerator MBT, accelerator TBzTD and processing aid WB222 into the masterbatch, setting the temperature to be 65-75 ℃ and the rotating speed to be 45-55rpm, mixing for 5-7min, observing the state of the sizing material every 2min during the mixing to ensure no carbon black agglomeration, and strictly controlling the temperature of the rubber discharging to be less than or equal to 100 ℃; S3, thin-pass granulation, namely putting the rubber compound obtained in the step S2 into an open mill, adjusting the roll gap to be 0.4-0.6mm, thin-pass for 4-6 times, adjusting the roll gap to be 1.8-2.2mm, discharging sheets, conveying the sheets into an underwater granulator, setting the rotating speed of a cutter to be 280-320rpm and the temperature of cooling water to be 18-22 ℃ to prepare cylindrical colloidal particles with the diameter of 2.8-3.2mm and the length of 3.8-4.2 mm; S4, two-stage vulcanization: S41, primary vulcanization, namely placing the rubber particles into a flat vulcanizing machine die, setting the temperature to 165-175 ℃ and the pressure to 9-11MPa, and preserving the heat for 8-12min to realize sizing material shaping and primary crosslinking; S42, secondary vulcanization, namely taking out the rubber material after primary vulcanization from the mold, transferring the rubber material into an electrothermal blowing oven, firstly preserving heat for 1.2-1.8h at 115-125 ℃, then raising the temperature to 155-165 ℃ and preserving heat for 2.5-3.5h, and controlling the air speed of hot air in the oven to be 0.6-1.0m/S to ensure the temperature uniformity; s43, cooling, namely naturally cooling the sizing material to room temperature after vulcanization is completed, wherein the cooling rate is less than or equal to 5 ℃ per minute, and internal stress is avoided to be generated, so that a final product is obtained.
  5. 5. The method for preparing rare earth modified EPDM rubber with low compression set according to claim 4, wherein the rotor torque of the internal mixer in the step S1 is stabilized at 80-100 N.m, and the temperature of the discharged masterbatch is less than or equal to 90 ℃.
  6. 6. The method for preparing a rare earth modified EPDM rubber with low compression set according to claim 4, wherein the rare earth oxide core-shell particles are prepared by: S01 primary modification, namely mixing rare earth oxides according to a set molar ratio, adding KH560, adjusting the pH value to 4.0-5.0, and reacting for 1.5-2.5 hours at the stirring speed of 250-350rpm at the temperature of 75-85 ℃; S02, washing and drying, namely centrifuging the reaction solution at 7000-9000rpm for 10-20min, collecting precipitate, washing with ethanol, and then drying for 3-5h at 55-65 ℃ and vacuum degree of-0.10 to-0.08 MPa to obtain Re-O-Si core-shell particles; S03, secondary modification, namely dispersing Re-O-Si core-shell particles in ethanol-water mixed solution, adding ionic liquid monomer, and reacting for 0.8-1.2h at 20-30 ℃ and stirring speed of 150-250 rpm; S04, spray drying, namely drying the reaction liquid by a spray dryer to obtain powdery rare earth oxide core-shell particles.
  7. 7. The preparation method of the rare earth modified EPDM rubber with low compression set according to claim 6, wherein the rare earth oxide comprises CeO 2 and La 2 O 3 , the particle size of CeO 2 is 50-80nm, the purity is more than or equal to 99.9%, the particle size of La 2 O 3 is 50-80nm, the purity is more than or equal to 99.9%, the mole ratio of CeO 2 to La 2 O 3 is 1:1-2:1, and the volume ratio of the ethanol-water mixture is 9:1.
  8. 8. The method for preparing a rare earth modified EPDM rubber with low compression set according to claim 4 or 6, wherein the ionic liquid monomer is selected from 1-vinyl-3-methylimidazole bis (trifluoromethanesulfonyl) imide salt or 1-carboxypropyl-3-methylimidazole bis (trifluoromethanesulfonyl) imide salt, and the purity is.
  9. 9. The method for preparing a rare earth modified EPDM rubber with low compression set according to claim 6, wherein KH560 is added with 10% -14% of the total mass of rare earth oxide.
  10. 10. The application of the rare earth modified EPDM rubber with low compression set is characterized in that the rare earth modified EPDM rubber obtained by adopting the preparation method of any one of claims 1-3 or any one of claims 4-9 is used for fuel cell bipolar plate sealing, LNG low-temperature flange gaskets, spacecraft hatch O-shaped rings, high-end building curtain wall sealing elements and rail transit vibration damping pads.

Description

Rare earth modified EPDM rubber with low compression set and preparation method and application thereof Technical Field The application belongs to the technical field of high polymer materials, and particularly relates to rare earth modified EPDM rubber with low compression set, a preparation method and application thereof. Background EPDM is excellent in terms of thermo-oxidative resistance, ozone resistance, and weather resistance by virtue of a main chain saturated structure, and is widely used in fields such as automobile sealing, building curtain walls, rail transit vibration-damping pads, and the like. But EPDM is non-self-reinforced rubber, and the Compression Set (CS) of the vulcanized rubber reaches 25% -35% under the conventional test condition of 100 ℃ multiplied by 70h/25% compression, so that the requirement of high-end scenes such as sealing of a bipolar plate of a fuel cell on CS being less than or equal to 10% is difficult to meet, and the application of the vulcanized rubber in the high-end field is limited. The existing technology for reducing the compression set of EPDM has the defects that the high-filling carbon black/white carbon black technology can cause the increase of the rubber density and the deterioration of the low-temperature rebound resilience, the thorough peroxide crosslinking technology has the problems of high scorching risk of rubber materials, high energy consumption and high cost, the metal oxide adding technology can only reduce CS to about 20 percent and is easy to frost out at high temperature, and the auxiliary crosslinking agent adding technology can cause the increase of the rubber hardness and the brittleness temperature and lose the low-temperature adaptability. In conclusion, the prior art cannot meet the multi-performance improvement requirements of low dosage, low hardness, low compression set, no CS rebound after aging, no frost precipitation and low temperature resistance, and the technical blank restricts the breakthrough of the EPDM to the high-end sealing field, so that the development of the EPDM composition with the comprehensive performance has important industrial value. Disclosure of Invention The application is carried out in view of the problems, and aims to provide an EPDM rubber composition containing a rare earth-organic synergistic structure, and a preparation method of the composition, wherein the composition can be realized by adopting conventional industrial equipment, uniform dispersion of rare earth particles in an EPDM matrix is realized through specific process design, agglomeration and frosting are avoided, the process energy consumption is low, the large-scale production can be realized, the application of the composition in the high-end sealing field is expanded, and the severe use requirements of scenes such as fuel cells, LNG equipment, spacecrafts and the like are met. The first aspect of the application provides a rare earth modified EPDM rubber with low compression set, which comprises the following raw materials, by weight, 100 parts of EPDM, 1.5-4.0 parts of rare earth oxide core-shell particles, 0.3-1.2 parts of ionic liquid monomer (IL), 0.3-0.8 parts of sulfur, 1.0-2.5 parts of phenolic resin cross-linking agent, 0.5-1.5 parts of Bismaleimide (BMI), 0.8-1.5 parts of accelerator MBT, 0.3-0.6 parts of accelerator TBzTD, 1.0-2.0 parts of anti-aging agent 445, 15-25 parts of paraffin oil, 40-60 parts of carbon black, 1.0 parts of stearic acid and 2.0 parts of processing aid WB 222; The ionic liquid monomer is selected from 1-vinyl-3-methylimidazole bis (trifluoromethanesulfonyl) imide salt or 1-carboxypropyl-3-methylimidazole bis (trifluoromethanesulfonyl) imide salt; The rare earth oxide core-shell particles are obtained by carrying out in-situ surface modification on rare earth oxide by triethoxysilane containing epoxy groups and ionic liquid monomers, and the rare earth oxide is CeO 2 and La 2O3. In any embodiment, the EPDM has an ENB content of 4.5wt% and a mooney viscosity ML (1+4) 125 ℃ 55±5. In any embodiment, the ionic liquid monomer is selected from 1-vinyl-3-methylimidazole bis (trifluoromethanesulfonyl) imide salt (VMIm NTf 2, vinyl type) or 1-carboxypropyl-3-methylimidazole bis (trifluoromethanesulfonyl) imide salt (CPMIm NTf 2, carboxyl type), with a purity of > 98%. In any embodiment, the ionic liquid monomer is used in an amount of 0.3 times the total molar amount of rare earth oxide. In any embodiment, the carbon black is at least one of N550, N330. The second aspect of the present application also provides a method for preparing a rare earth modified EPDM rubber having a low compression set, comprising the steps of: s1, preparing master batch, namely adding 30phr of EPDM, rare earth oxide core-shell particles, ionic liquid monomer, anti-aging agent 445 and stearic acid into an internal mixer, setting the temperature to be 75-85 ℃ and the rotating speed to be 55-65rpm, mixing for 3-5min, and discharging the mas