A wear-resistant high-rebound sealing material and preparation method thereof

Abstract

The present invention relates to the field of rubber sealing technology, and in particular to a wear-resistant high-rebound sealing material and a preparation method thereof. The above-mentioned wear-resistant high-rebound sealing material, its raw materials include by mass: 80-120 parts of EPDM rubber, 10-30 parts of styrene-butadiene rubber, 50-80 parts of wear-resistant filler, 1-2 parts of zinc oxide, 5-15 parts of cyclohexane oil KN4010, 1-2 parts of titanate coupling agent, 1-2 parts of di(tert-butylperoxyisopropyl)benzene, 1-3 parts of sulfur, 1-2 parts of vulcanization accelerator OTTBS, 0.1-1 parts of trimethylolpropane triacrylate, and 1-2 parts of antioxidant. The present invention adopts a specific raw material formula and cooperates with a specific process to obtain an EPDM composite rubber material with high resilience and low compression permanent deformation. It can have excellent mechanical properties on the basis of meeting elastic sealing performance, and the preparation method is simple, which is suitable for large-scale promotion and application.

Description

Technical Field

[0001] The invention relates to the technical field of rubber sealing, and in particular to a wear-resistant high-rebound sealing material and a preparation method thereof. Background Art

[0002] Sealing materials are materials that prevent fluids or solid particles from leaking between adjacent joint surfaces, and prevent foreign matter (such as dust and moisture) from invading the interior of machinery and equipment. Resilience and wear resistance are important indicators of sealing materials. Improving the wear resistance and resilience of sealing materials can extend the service life of sealing materials and the durability of sealing.

[0003] Traditional sealing materials mostly use a single type of rubber as the main rubber, combined with conventional additives and carbon black to make a mixed rubber. While meeting certain performance requirements, other performance requirements are poor and the cost is high. Existing sealing materials have a short service life, and common failure forms are wear, aging, and lack of elasticity.

[0004] Since the main chain of EPDM is saturated and only the side chain contains a small amount of double bonds, it has excellent resistance to high and low temperatures, heat and oxygen aging, weather resistance, chemical media resistance and electrical insulation. However, the bonding force between its internal molecular chains is small, which leads to relative sliding between the molecular chains and poor wear resistance. This has a relatively adverse effect on EPDM in the field of sealing materials. It must be reinforced to meet application requirements. Conventional nanofillers are used for reinforcement, but the dispersion is poor and the reinforcement effect is unsatisfactory, which often leads to a decrease in the sealing effect and an increase in the frequency of replacement of sealing materials.

[0005] How to strengthen EPDM rubber to meet the requirements of sealing materials, give it excellent mechanical toughness, resilience and wear resistance, and improve the sealing service life of sealing materials has excellent research prospects. Summary of the invention

[0006] The purpose of the present invention is to solve the shortcomings of the prior art and to propose a wear-resistant high-rebound sealing material and a preparation method thereof.

[0007] A wear-resistant high-rebound sealing material, whose raw materials include, by mass: 80-120 parts of EPDM rubber, 10-30 parts of styrene-butadiene rubber, 50-80 parts of wear-resistant filler, 1-2 parts of zinc oxide, 5-15 parts of cyclohexane oil KN4010, 1-2 parts of titanate coupling agent, 1-2 parts of di(tert-butylperoxyisopropyl)benzene, 1-3 parts of sulfur, 1-2 parts of vulcanization accelerator OTTBS, 0.1-1 parts of trimethylolpropane triacrylate, and 1-2 parts of antioxidant.

[0008] Preferably, the wear-resistant filler comprises: graphene oxide composite and hydrophobic precipitated silica, and the mass ratio of the graphene oxide composite and the hydrophobic precipitated silica is 10-20:40-60.

[0009] Preferably, the hydrophobic precipitated silica is prepared by the following specific operation: mixing the silane coupling agent KH570 with the precipitated silica, adjusting the pH value of the system to 4-5, heating to 80-90° C., keeping the temperature for 100-140 minutes, washing, and drying.

[0010] More preferably, the mass ratio of silane coupling agent KH570 to precipitated silica is 1.5-2.5:100.

[0011] Preferably, the graphene oxide composite is prepared by the following steps: adding silicate mineral powder to water and stirring for 1-2 hours, adding graphene oxide thereto and ultrasonically treating for 1-2 hours, adding Tris-HCl buffer and stirring evenly, adding dopamine hydrochloride thereto and ultrasonically treating for 1-2 hours, standing for 2-6 hours, filtering, washing, vacuum drying, grinding and sieving.

[0012] More preferably, the silicate mineral powder is at least one of talc powder, muscovite powder and montmorillonite powder.

[0013] More preferably, the mass ratio of silicate mineral powder, graphite oxide and dopamine hydrochloride is 5-10:1-2:1-2.

[0014] More preferably, the ultrasound frequency is 5-10 kHz.

[0015] Preferably, the Mooney viscosity of the EPDM rubber is 61ML(1+4)125°C and the ethylene content is 62-65%.

[0016] The preparation method of the above-mentioned wear-resistant high-resilient sealing material comprises the following steps:

[0017] S1. Cool the styrene-butadiene rubber to -80~-100℃ with liquid nitrogen, crush and sieve at low temperature, and use 60 Co is used as the radiation source, and gamma rays are irradiated in an air atmosphere; EPDM rubber and wear-resistant filler are added thereto, mixed, and kneaded at 110-120° C. for 5-10 minutes to obtain a mixed material a;

[0018] S2, add cyclohexane oil KN4010, zinc oxide, titanate coupling agent, bis(tert-butylperoxyisopropyl)benzene, sulfur, vulcanization accelerator OTTBS, trimethylolpropane triacrylate, antioxidant to mixed material a, mix at 110-120° C. for 5-10 min to obtain mixed rubber b;

[0019] S3. Heat the mixed rubber b evenly, extrude it into shape, vulcanize it on a plate at 150-158℃ for 5-7min, and the pressure of vulcanization on the plate is 14-16MPa; perform secondary vulcanization at 170-180℃ for 20-30min, and cool it to room temperature.

[0020] Preferably, in S1, the γ-ray irradiation dose is 5-15 kGy. Beneficial effects: The present invention irradiates styrene-butadiene rubber and then compounds it with EPDM rubber and wear-resistant fillers, which has good mixing compatibility and constructs a multi-layered structure in the organic system, greatly improving the sealing resilience of the product, effectively reducing the compression permanent deformation and stress relaxation of EPDM rubber, and significantly extending the service life of EPDM rubber seals.

[0021] The present invention loads graphene oxide on the layered structure of silicate minerals, and then deposits polydopamine on the surface thereof. Not only is the graphene oxide not easy to fall off, but also it has high affinity with styrene-butadiene rubber and EPDM rubber, and has high mutual bonding strength after mixing. Compared with directly adding layered silicate minerals, the tensile strength of the product is significantly improved, and at the same time, the product can be given excellent wear resistance and excellent durability, especially maintaining excellent sealing performance after radiation aging.

[0022] The present invention increases the bonding force between the internal molecular chains, effectively reduces the relative sliding between the molecular chains, cooperates with the wear-resistant filler and the cyclohexane oil KN4010, effectively adjusts the internal adhesion, further reduces the compression permanent deformation, ensures the sealing effect of the EPDM rubber sealing material, and has excellent elastic sealing performance.

[0023] The present invention adopts a specific raw material formula and cooperates with a specific process to prepare an EPDM composite rubber material with high resilience and low compression permanent deformation. On the basis of meeting the elastic sealing performance, the material has excellent mechanical properties, and the preparation method is simple, so the material is suitable for large-scale promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a comparison chart of the tensile strength and resilience of the sealing materials obtained in Example 5 and Comparative Examples 1-3.

[0025] Figure 2 The figure is a comparison chart of the compression permanent deformation and DIN wear loss of the sealing materials obtained in Example 5 and Comparative Examples 1-3.

[0026] Figure 3 It is a comparison chart of the tensile strength retention rate and the rebound retention rate of the sealing materials obtained in Example 5 and Comparative Examples 1-3. DETAILED DESCRIPTION

[0027] The present invention will be further explained below in conjunction with specific embodiments.

[0028] The EPDM rubber used in the following is from Sinopec Mitsui, with the grade of EPDM 3092M, Mooney viscosity of 59ML(1+4)125°C, and ethylene content of 49.5%. The styrene butadiene rubber used in the following is from Yuehua Petrochemical, with the grade of SBS 792, and S / B (mass ratio) of 20 / 80. The naphthenic oil KN4010 used in the following is purchased from Guangdong Xite Energy Saving and Environmental Protection Technology Co., Ltd.

[0029] The hydrophobic precipitated silica used below was prepared by the following specific operation: 2g of silane coupling agent KH570 was added to 10g of anhydrous ethanol and mixed evenly, then 100g of precipitated silica was added and mixed evenly, the pH value of the system was adjusted to 4.5, heated to 85°C, kept warm for 120min, washed, and dried at 105°C to constant weight. The DBP value of the hydrophobic precipitated silica used was 2.25mL / g, and the lipophilicity was 10.12%.

[0030] Example 1: A wear-resistant and high-resilient sealing material, whose raw materials include: 80g of EPDM rubber, 10g of styrene-butadiene rubber, 50g of wear-resistant filler, 1g of zinc oxide, 5g of cyclohexane oil KN4010, 1g of titanate coupling agent TMC-201, 1g of di(tert-butylperoxyisopropyl)benzene, 1g of sulfur, 1g of vulcanization accelerator OTTBS, 0.1g of trimethylolpropane triacrylate, and 1g of antioxidant RD.

[0031] The wear-resistant filler is composed of a graphene oxide composite and hydrophobic precipitated white carbon black in a mass ratio of 1:4. The graphene oxide composite is prepared by the following steps: 5g of talc is added to 30g of deionized water, stirred at a speed of 1000r / min for 1h, 1g of graphene oxide is added thereto and ultrasonically treated for 1h at an ultrasonic frequency of 5kHz, 20g of Tris-HCl buffer with a pH of 9-9.8 is added thereto and stirred evenly, 1g of dopamine hydrochloride is added thereto and ultrasonically treated for 1h at an ultrasonic frequency of 5kHz, allowed to stand for 2h, filtered, washed with deionized water, vacuum dried, and ground through a 100-mesh sieve.

[0032] The preparation method of the above-mentioned wear-resistant high-resilient sealing material comprises the following steps:

[0033] S1. Cool the styrene-butadiene rubber to -80℃ with liquid nitrogen, crush it at low temperature and pass it through a 10-mesh sieve. 60 Co was used as the radiation source, and gamma rays were irradiated in an air atmosphere with an irradiation dose of 5 kGy; EPDM rubber and wear-resistant filler were added thereto, and the mixture was added to an internal mixer for mixing at a temperature of 110° C. for 5 minutes to obtain a mixed material a;

[0034] S2, add cyclohexane oil KN4010, zinc oxide, titanate coupling agent TMC-201, di(tert-butylperoxyisopropyl)benzene, sulfur, vulcanization accelerator OTTBS, trimethylolpropane triacrylate, antioxidant RD to mixed material a, mix at a temperature of 110° C. for 5 minutes to obtain mixed rubber b;

[0035] S3. The mixed rubber b is sent to an open mill for uniform heat refining, extruded and formed, and sent to a flat vulcanizer for vulcanization at a temperature of 150°C for 5 minutes and a vulcanization pressure of 14 MPa. It is sent to a hot oven for secondary vulcanization at a temperature of 170°C for 20 minutes and then cooled to room temperature.

[0036] Example 2: A wear-resistant and high-resilient sealing material, whose raw materials include: 120g of EPDM rubber, 30g of styrene-butadiene rubber, 80g of wear-resistant filler, 2g of zinc oxide, 15g of cyclohexane oil KN4010, 2g of titanate coupling agent TMC-201, 2g of di(tert-butylperoxyisopropyl)benzene, 3g of sulfur, 2g of vulcanization accelerator OTTBS, 1g of trimethylolpropane triacrylate, and 2g of antioxidant RD.

[0037] The wear-resistant filler is composed of a graphene oxide composite and hydrophobic precipitated white carbon black in a mass ratio of 1:3. The graphene oxide composite is prepared by the following steps: 10g of talc is added to 60g of deionized water, stirred at a speed of 2000r / min for 2h, 2g of graphene oxide is added thereto and ultrasonically treated for 2h at an ultrasonic frequency of 10kHz, 40g of Tris-HCl buffer with a pH of 9-9.8 is added thereto and stirred evenly, 2g of dopamine hydrochloride is added thereto and ultrasonically treated for 2h at an ultrasonic frequency of 10kHz, standing for 6h, filtering, washing with deionized water, vacuum drying, and grinding through a 100-mesh sieve.

[0038] The preparation method of the above-mentioned wear-resistant high-resilient sealing material comprises the following steps:

[0039] S1. Cool the styrene-butadiene rubber to -100℃ with liquid nitrogen, crush it at low temperature and pass it through a 10-mesh sieve. 60 Co was used as the radiation source, and gamma rays were irradiated in an air atmosphere with an irradiation dose of 15 kGy; EPDM rubber and wear-resistant filler were added thereto, and the mixture was added to an internal mixer for mixing at a temperature of 120° C. for 10 minutes to obtain a mixed material a;

[0040] S2, adding cyclohexane oil KN4010, zinc oxide, titanate coupling agent TMC-201, di(tert-butylperoxyisopropyl)benzene, sulfur, vulcanization accelerator OTTBS, trimethylolpropane triacrylate, antioxidant RD to mixed material a, mixing at a temperature of 120° C. for 10 min to obtain mixed rubber b;

[0041] S3. The mixed rubber b is sent to an open mill for uniform heat refining, extruded and formed, and sent to a flat vulcanizer for vulcanization at a temperature of 158°C for 7 minutes and a vulcanization pressure of 16MPa. It is sent to a hot oven for secondary vulcanization at a temperature of 180°C for 30 minutes and then cooled to room temperature.

[0042] Example 3: A wear-resistant and high-resilient sealing material, whose raw materials include: 90g EPDM rubber, 25g styrene-butadiene rubber, 63g wear-resistant filler, 1.7g zinc oxide, 8g cyclohexane oil KN4010, 1.7g titanate coupling agent TMC-201, 1.2g di(tert-butylperoxyisopropyl)benzene, 2.5g sulfur, 1.2g vulcanization accelerator OTTBS, 0.7g trimethylolpropane triacrylate, and 1.3g antioxidant RD.

[0043] The wear-resistant filler is composed of a graphene oxide composite and hydrophobic precipitated white carbon black in a mass ratio of 2:5. The graphene oxide composite is prepared by the following steps: 9g of montmorillonite powder is added to 40g of deionized water, stirred at a speed of 1800r / min for 80min, 1.7g of graphene oxide is added thereto and ultrasonically treated for 80min at an ultrasonic frequency of 9kHz, 25g of Tris-HCl buffer with a pH of 9-9.8 is added and stirred evenly, 1.7g of dopamine hydrochloride is added thereto and ultrasonically treated for 80min at an ultrasonic frequency of 9kHz, standing for 3h, filtering, washing with deionized water, vacuum drying, and grinding through a 100-mesh sieve.

[0044] The preparation method of the above-mentioned wear-resistant high-resilient sealing material comprises the following steps:

[0045] S1. Cool the styrene-butadiene rubber to -95°C with liquid nitrogen, crush it at low temperature and pass it through a 10-mesh sieve. 60 Co was used as the radiation source, and gamma rays were irradiated in an air atmosphere with an irradiation dose of 8 kGy; EPDM rubber and wear-resistant filler were added thereto, and the mixture was added to an internal mixer for mixing at a temperature of 118° C. for 7 minutes to obtain a mixed material a;

[0046] S2, add cyclohexane oil KN4010, zinc oxide, titanate coupling agent TMC-201, di(tert-butylperoxyisopropyl)benzene, sulfur, vulcanization accelerator OTTBS, trimethylolpropane triacrylate, antioxidant RD to mixed material a, mix at a temperature of 118° C. for 7 minutes to obtain mixed rubber b;

[0047] S3. The mixed rubber b is sent to an open mill for uniform heat refining, extruded and formed, and sent to a flat vulcanizer for vulcanization at a temperature of 156°C for 5.5 minutes and a vulcanization pressure of 15.5 MPa. It is sent to a hot oven for secondary vulcanization at a temperature of 173°C for 28 minutes and then cooled to room temperature.

[0048] Example 4: A wear-resistant and high-resilient sealing material, whose raw materials include: 110g of EPDM rubber, 15g of styrene-butadiene rubber, 67g of wear-resistant filler, 1.3g of zinc oxide, 12g of cyclohexane oil KN4010, 1.3g of titanate coupling agent TMC-201, 1.8g of di(tert-butylperoxyisopropyl)benzene, 1.5g of sulfur, 1.8g of vulcanization accelerator OTTBS, 0.3g of trimethylolpropane triacrylate, and 1.7g of antioxidant RD.

[0049] The wear-resistant filler is composed of a graphene oxide composite and hydrophobic precipitated white carbon black in a mass ratio of 12:55. The graphene oxide composite is prepared by the following steps: 7g of montmorillonite powder is added to 50g of deionized water, stirred at a speed of 1200r / min for 100min, 1.3g of graphene oxide is added thereto and ultrasonically treated for 100min, the ultrasonic frequency is 6kHz, 35g of Tris-HCl buffer with pH=9-9.8 is added and stirred evenly, 1.3g of dopamine hydrochloride is added thereto and ultrasonically treated for 100min, the ultrasonic frequency is 6kHz, standing for 5h, filtering, washing with deionized water, vacuum drying, and grinding through a 100-mesh sieve.

[0050] The preparation method of the above-mentioned wear-resistant high-resilient sealing material comprises the following steps:

[0051] S1. Cool the styrene-butadiene rubber to -85°C with liquid nitrogen, crush it at low temperature and pass it through a 10-mesh sieve. 60 Co was used as the radiation source, and gamma rays were irradiated in an air atmosphere with an irradiation dose of 12 kGy; EPDM rubber and wear-resistant filler were added thereto, and the mixture was added to an internal mixer for mixing at a temperature of 112° C. for 9 minutes to obtain a mixed material a;

[0052] S2, add cyclohexane oil KN4010, zinc oxide, titanate coupling agent TMC-201, di(tert-butylperoxyisopropyl)benzene, sulfur, vulcanization accelerator OTTBS, trimethylolpropane triacrylate, antioxidant RD to mixed material a, mix at a temperature of 112° C. for 9 minutes to obtain mixed rubber b;

[0053] S3. The mixed rubber b is sent to an open mill for uniform heat refining, extruded and formed, and sent to a flat vulcanizer for vulcanization at a temperature of 152°C for 6.5 minutes and a vulcanization pressure of 14.5 MPa. It is sent to a hot oven for secondary vulcanization at a temperature of 177°C for 22 minutes and then cooled to room temperature.

[0054] Example 5: A wear-resistant and high-resilient sealing material, whose raw materials include: 100g of EPDM rubber, 20g of styrene-butadiene rubber, 65g of wear-resistant filler, 1.5g of zinc oxide, 10g of cyclohexane oil KN4010, 1.5g of titanate coupling agent TMC-201, 1.5g of di(tert-butylperoxyisopropyl)benzene, 2g of sulfur, 1.5g of vulcanization accelerator OTTBS, 0.5g of trimethylolpropane triacrylate, and 1.5g of antioxidant RD.

[0055] The wear-resistant filler is composed of a graphene oxide composite and hydrophobic precipitated white carbon black in a mass ratio of 3:10. The graphene oxide composite is prepared by the following steps: 8g of muscovite powder is added to 45g of deionized water, stirred at a speed of 1500r / min for 90min, 1.5g of graphene oxide is added thereto and ultrasonically treated for 90min at an ultrasonic frequency of 7.5kHz, 30g of Tris-HCl buffer with a pH of 9-9.8 is added and stirred evenly, 1.5g of dopamine hydrochloride is added thereto and ultrasonically treated for 90min at an ultrasonic frequency of 7.5kHz, allowed to stand for 4h, filtered, washed with deionized water, vacuum dried, and ground through a 100-mesh sieve.

[0056] The preparation method of the above-mentioned wear-resistant high-resilient sealing material comprises the following steps:

[0057] S1. Cool the styrene-butadiene rubber to -90℃ with liquid nitrogen, crush it at low temperature and pass it through a 10-mesh sieve. 60 Co was used as the radiation source, and gamma rays were irradiated in an air atmosphere with an irradiation dose of 10 kGy; EPDM rubber and wear-resistant filler were added thereto, and the mixture was added to an internal mixer for mixing at a temperature of 115° C. for 8 minutes to obtain a mixed material a;

[0058] S2, add cyclohexane oil KN4010, zinc oxide, titanate coupling agent TMC-201, di(tert-butylperoxyisopropyl)benzene, sulfur, vulcanization accelerator OTTBS, trimethylolpropane triacrylate, antioxidant RD to mixed material a, mix at a temperature of 115° C. for 8 minutes to obtain mixed rubber b;

[0059] S3. The mixed rubber b is sent to an open mill for uniform heat refining, extruded and formed, and sent to a flat vulcanizer for vulcanization at a temperature of 154°C for 6 minutes and a vulcanization pressure of 15MPa. It is sent to a hot oven for vulcanization at a temperature of 175°C for 25 minutes and then cooled to room temperature.

[0060] Comparative Example 1: A sealing material, whose raw materials include: 100g EPDM rubber, 20g styrene-butadiene rubber, 65g wear-resistant filler, 1.5g zinc oxide, 10g cyclohexane oil KN4010, 1.5g titanate coupling agent TMC-201, 1.5g di(tert-butylperoxyisopropyl)benzene, 2g sulfur, 1.5g vulcanization accelerator OTTBS, 0.5g trimethylolpropane triacrylate, and 1.5g antioxidant RD.

[0061] The wear-resistant filler is composed of a graphene oxide composite and hydrophobic precipitated white carbon black in a mass ratio of 3:10. The graphene oxide composite is prepared by the following steps: 8g of muscovite powder is added to 45g of deionized water, stirred at a speed of 1500r / min for 90min, 1.5g of graphene oxide is added thereto and ultrasonically treated for 90min at an ultrasonic frequency of 7.5kHz, 30g of Tris-HCl buffer with a pH of 9-9.8 is added and stirred evenly, 1.5g of dopamine hydrochloride is added thereto and ultrasonically treated for 90min at an ultrasonic frequency of 7.5kHz, allowed to stand for 4h, filtered, washed with deionized water, vacuum dried, and ground through a 100-mesh sieve.

[0062] The method for preparing the sealing material comprises the following steps:

[0063] S1, adding styrene-butadiene rubber, EPDM rubber and wear-resistant filler into an internal mixer for mixing at a temperature of 115° C. for 8 min to obtain a mixed material a;

[0064] S2, add cyclohexane oil KN4010, zinc oxide, titanate coupling agent TMC-201, di(tert-butylperoxyisopropyl)benzene, sulfur, vulcanization accelerator OTTBS, trimethylolpropane triacrylate, antioxidant RD to mixed material a, mix at a temperature of 115° C. for 8 minutes to obtain mixed rubber b;

[0065] S3. The mixed rubber b is sent to an open mill for uniform heat refining, extruded and formed, and sent to a flat vulcanizer for vulcanization at a temperature of 154°C for 6 minutes and a vulcanization pressure of 15MPa. It is sent to a hot oven for vulcanization at a temperature of 175°C for 25 minutes and then cooled to room temperature.

[0066] Comparative Example 2: A sealing material, whose raw materials include: 100g EPDM rubber, 20g styrene-butadiene rubber, 65g wear-resistant filler, 1.5g zinc oxide, 10g cyclohexane oil KN4010, 1.5g titanate coupling agent TMC-201, 1.5g di(tert-butylperoxide isopropyl)benzene, 2g sulfur, 1.5g vulcanization accelerator OTTBS, 0.5g trimethylolpropane triacrylate, and 1.5g antioxidant RD.

[0067] The wear-resistant filler is composed of muscovite powder and hydrophobic precipitated silica in a mass ratio of 3:10.

[0068] The method for preparing the sealing material comprises the following steps:

[0069] S1. Cool the styrene-butadiene rubber to -90℃ with liquid nitrogen, crush it at low temperature and pass it through a 10-mesh sieve. 60 Co was used as the radiation source, and gamma rays were irradiated in an air atmosphere with an irradiation dose of 10 kGy; EPDM rubber and wear-resistant filler were added thereto, and the mixture was added to an internal mixer for mixing at a temperature of 115° C. for 8 minutes to obtain a mixed material a;

[0070] S2, add cyclohexane oil KN4010, zinc oxide, titanate coupling agent TMC-201, di(tert-butylperoxyisopropyl)benzene, sulfur, vulcanization accelerator OTTBS, trimethylolpropane triacrylate, antioxidant RD to mixed material a, mix at a temperature of 115° C. for 8 minutes to obtain mixed rubber b;

[0071] S3. The mixed rubber b is sent to an open mill for uniform heat refining, extruded and formed, and sent to a flat vulcanizer for vulcanization at a temperature of 154°C for 6 minutes and a vulcanization pressure of 15MPa. It is sent to a hot oven for vulcanization at a temperature of 175°C for 25 minutes and then cooled to room temperature.

[0072] Comparative Example 3: A sealing material, whose raw materials include: 100g EPDM rubber, 20g styrene-butadiene rubber, 65g wear-resistant filler, 1.5g zinc oxide, 10g cyclohexane oil KN4010, 1.5g titanate coupling agent TMC-201, 1.5g di(tert-butylperoxide isopropyl)benzene, 2g sulfur, 1.5g vulcanization accelerator OTTBS, 0.5g trimethylolpropane triacrylate, and 1.5g antioxidant RD.

[0073] The wear-resistant filler is composed of a graphene oxide composite and hydrophobic precipitated silica in a mass ratio of 3:10. The graphene oxide composite is prepared by the following steps: 8 g of muscovite powder is added to 45 g of deionized water, stirred at a speed of 1500 r / min for 90 min, 1.5 g of graphene oxide is added thereto, ultrasonically treated for 90 min at an ultrasonic frequency of 7.5 kHz, filtered, washed with deionized water, vacuum dried, and ground through a 100 mesh sieve.

[0074] The method for preparing the sealing material comprises the following steps:

[0075] S1. Cool the styrene-butadiene rubber to -90℃ with liquid nitrogen, crush it at low temperature and pass it through a 10-mesh sieve. 60 Co was used as the radiation source, and gamma rays were irradiated in an air atmosphere with an irradiation dose of 10 kGy; EPDM rubber and wear-resistant filler were added thereto, and the mixture was added to an internal mixer for mixing at a temperature of 115° C. for 8 minutes to obtain a mixed material a;

[0076] S2, add cyclohexane oil KN4010, zinc oxide, titanate coupling agent TMC-201, di(tert-butylperoxyisopropyl)benzene, sulfur, vulcanization accelerator OTTBS, trimethylolpropane triacrylate, antioxidant RD to mixed material a, mix at a temperature of 115° C. for 8 minutes to obtain mixed rubber b;

[0077] S3. The mixed rubber b is sent to an open mill for uniform heat refining, extruded and formed, and sent to a flat vulcanizer for vulcanization at a temperature of 154°C for 6 minutes and a vulcanization pressure of 15MPa. It is sent to a hot oven for vulcanization at a temperature of 175°C for 25 minutes and then cooled to room temperature.

[0078] The sealing materials obtained in Example 5 and Comparative Examples 1-3 were subjected to performance tests, as follows:

[0079] (1) The tensile strength of each group of samples was measured with reference to GB / T 528-2009 “Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber”;

[0080] (2) Determine the rebound rate of each group of samples with reference to GB / T 1681-2009 “Determination of rebound elasticity of vulcanized rubber”;

[0081] (3) Referring to GB / T 7759.1-2015 “Determination of compression set of vulcanized rubber or thermoplastic rubber Part 1: At room temperature and elevated temperature”, the compression set (120°C × 168h) of each group of samples was measured;

[0082] (4) The DIN wear resistance of each group of samples was tested using a DIN rubber wear tester (weight: 5N; abrasive cloth: 60#; roller diameter: 150mm; roller length: 460mm; roller speed: 40rpm).

[0083] like Figure 1 and Figure 2 As shown, the tensile strength and rebound rate of the sealing material obtained in Example 5 are both the highest, while the compression permanent deformation and DIN abrasion loss are both the smallest, which is better than that of Comparative Examples 1-3 (P < 0.05).

[0084] The sealing materials obtained in Example 5 and Comparative Examples 1-3 were subjected to γ-ray irradiation aging, with a cumulative dose of 4×10 7 rad, the tensile strength and rebound rate of each group of samples were measured again, and the retention rate of tensile strength and rebound rate was calculated.

[0085] Tensile strength retention rate = tensile strength after irradiation aging ÷ original tensile strength × 100%

[0086] Resilience retention rate = Resilience after irradiation aging ÷ Original resilience × 100%

[0087] like Figure 3 As shown, the tensile strength retention rate and the rebound retention rate of the sealing material obtained in Example 5 are the highest, which are better than those of Comparative Examples 1-3 (P < 0.05), which proves that the sealing material obtained in the present invention has excellent aging resistance and can still maintain excellent sealing performance after radiation aging.

[0088] The applicant believes that this is because the present invention irradiates styrene-butadiene rubber, and then mixes it with EPDM rubber and wear-resistant filler, which has good mixing compatibility, builds a multi-layered structure in the organic system, greatly improves the product sealing resilience, effectively reduces the compression permanent deformation and stress relaxation of EPDM rubber, and significantly extends the service life of EPDM rubber sealing. The present invention loads graphene oxide on the layered structure of silicate minerals, and then deposits polydopamine on its surface. Not only is graphene oxide not easy to fall off, but also has high affinity with styrene-butadiene rubber and EPDM rubber, and has high mutual bonding strength after mixing, the tensile strength of the product is significantly improved, and at the same time, it can give the product excellent wear resistance and excellent durability, especially after irradiation aging, it still maintains excellent sealing performance. At the same time, the bonding force between the internal molecular chains in the present invention is increased, which effectively reduces the relative sliding between the molecular chains, cooperates with the wear-resistant filler and cyclohexane oil KN4010, effectively adjusts the internal adhesion, further reduces its compression permanent deformation, ensures the sealing effect of EPDM rubber sealing material, and has excellent elastic sealing performance.

[0089] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A wear-resistant and high-rebound sealing material, characterized in that: The raw materials include, by mass: 80-120 parts of EPDM rubber, 10-30 parts of styrene-butadiene rubber, 50-80 parts of wear-resistant filler, 1-2 parts of zinc oxide, 5-15 parts of naphthenic oil KN4010, 1-2 parts of titanate coupling agent, 1-2 parts of di(tert-butylperoxyisopropyl)benzene, 1-3 parts of sulfur, 1-2 parts of vulcanization accelerator OTTBS, 0.1-1 parts of trimethylolpropane triacrylate, and 1-2 parts of antioxidant; Among them, the styrene-butadiene rubber is cooled to -80~-100℃ by liquid nitrogen, crushed and sieved at low temperature, and then 60 Co was used as the radiation source and γ-ray irradiation treatment was carried out in air atmosphere; The wear-resistant filler includes: graphene oxide composite and hydrophobic precipitated silica, wherein the mass ratio of the graphene oxide composite and the hydrophobic precipitated silica is 10-20:40-60; The graphene oxide composite is prepared by the following steps: adding silicate mineral powder to water and stirring for 1-2 hours, adding graphene oxide thereto and ultrasonically treating it for 1-2 hours, adding Tris-HCl buffer and stirring evenly, adding dopamine hydrochloride thereto and ultrasonically treating it for 1-2 hours, standing for 2-6 hours, filtering, washing, vacuum drying, grinding and sieving.

2. The wear-resistant high-resilience sealing material according to claim 1, characterized in that: The hydrophobic precipitated silica is prepared by the following specific operation: mixing silane coupling agent KH570 with precipitated silica, adjusting the pH value of the system to 4-5, heating to 80-90°C, keeping the temperature for 100-140 minutes, washing, and drying; The mass ratio of silane coupling agent KH570 to precipitated silica is 1.5-2.5:

100.

3. The wear-resistant high-resilience sealing material according to claim 1, characterized in that: The silicate mineral powder is at least one of talc powder, muscovite powder and montmorillonite powder.

4. The wear-resistant high-resilience sealing material according to claim 1, characterized in that: The mass ratio of silicate mineral powder, graphite oxide and dopamine hydrochloride is 5-10:1-2:1-2.

5. The wear-resistant high-resilience sealing material according to claim 1, characterized in that: The ultrasound frequency is 5-10kHz.

6. The wear-resistant high-resilience sealing material according to claim 1, characterized in that: The Mooney viscosity of EPDM rubber is 55-60ML (1+4) 125°C, and the ethylene content is 48-50%.

7. A method for preparing the wear-resistant high-resilience sealing material according to any one of claims 1 to 6, characterized in that: The steps include: S1. Cool the styrene-butadiene rubber to -80~-100℃ with liquid nitrogen, crush and sieve at low temperature, and use 60 Co is used as the radiation source, and gamma rays are irradiated in an air atmosphere; EPDM rubber and wear-resistant filler are added thereto, mixed, and kneaded at 110-120° C. for 5-10 minutes to obtain a mixed material a; S2, add cyclohexane oil KN4010, zinc oxide, titanate coupling agent, bis(tert-butylperoxyisopropyl)benzene, sulfur, vulcanization accelerator OTTBS, trimethylolpropane triacrylate, antioxidant to mixed material a, mix at 110-120° C. for 5-10 min to obtain mixed rubber b; S3. Heat the mixed rubber b evenly, extrude it into shape, vulcanize it on a plate at 150-158℃ for 5-7min, and the pressure of vulcanization on the plate is 14-16MPa; perform secondary vulcanization at 170-180℃ for 20-30min, and cool it to room temperature.

8. The method for preparing the wear-resistant high-resilience sealing material according to claim 7, characterized in that: In S1, the γ-ray irradiation dose is 5-15 kGy.

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