Seawater-corrosion-resistant, high-resilience and low-compression-deformation modified ethylene propylene diene monomer rubber material as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of rubber preparation, and discloses a seawater-corrosion-resistant high-resilience low-compression-deformation modified ethylene propylene diene monomer rubber material as well as a preparation method and application thereof. The modified ethylene propylene diene monomer material comprises the following components: ethylene propylene diene monomer, a polyolefin elastomer, a filler, a processing aid, tackifying resin, an anti-aging agent, and at least one of an optional softening dispersant, a vulcanizing agent, an accelerant and a scorch retarder, the processing aid comprises zinc methacrylate; the accelerant comprises p-benzoquinone dioxime; and the anti-aging agent comprises 2, 6-di-tert-butyl-4-methylphenol. According to the invention, from the perspective of formula design, the high-temperature thermo-oxidative aging resistance, the hydrothermal thermal aging resistance and the compression permanent deformation resistance in a high-concentration seawater environment of the EPDM are improved in a targeted manner.

Description

Technical Field

[0001] The invention belongs to the technical field of rubber preparation, and more specifically, relates to a modified EPDM rubber material with high resilience and low compression deformation and resistance to seawater erosion, a preparation method and an application thereof. Background Art

[0002] There are many islands in some areas, and the ocean makes transportation inconvenient. The existing bridges and tunnels cannot meet their transportation needs, which seriously hinders the economic development of the region. In order to meet the needs of cross-regional, inter-provincial and inter-city transportation, the construction of various undersea tunnels has become an inevitable trend.

[0003] During the construction of the tunnel, the sealing between the segments needs to be considered. At present, there are obvious technical shortcomings in tunnel sealing. According to reports, the leakage rate of the segment joints of Shanghai Metro Line 1 reached 85%. From a technical point of view, the leakage is mostly caused by the failure of the rubber gasket. Pressure causes the rubber molecular chain to shift, oxidation causes some covalent bonds to break, and after long-term action, the elasticity of the material decreases, allowing external high-pressure media to invade.

[0004] Compared with ordinary municipal tunnels and mountain tunnels, submarine tunnels face the problem of high concentration ion corrosion and high water pressure. Seawater contains a large amount of Na + , K + Mg 2+ , Ca 2+ , Cl - 、SO4 2- Br - 、CO3 2- 、HCO3 - , water pressure up to 1Mpa+. Among them, ions have a significant accelerating effect on rubber aging, which will directly cause changes in functional groups and breakage of molecular bonds. However, there are few studies in the industry on the changes in rubber performance under high ion concentrations, and many mechanisms are still unclear. Therefore, this is also one of the most difficult hurdles to overcome in submarine tunnel sealing. During long-term load service, the waterproof materials at the joints of rubber sealing segments have been damaged to varying degrees, and water leakage has occurred. This is because high temperature, hot water immersion, and thermal oxygen aging have greatly accelerated the aging speed of rubber, which is completely different from the aging mechanism exposed to the air at room temperature.

[0005] At present, the engineering community generally uses EPDM (ethylene propylene diene monomer rubber) as a shield tunnel segment sealing material, a rubber waterstop for railway tunnels, or a sealing gasket for waterproofing. This material is a terpolymer formed by the polymerization of ethylene, propylene, and non-conjugated dienes. The main chain is completely saturated (chemically stable) and contains only a small amount of unsaturated double bonds in the side chain. Therefore, it has excellent oxidation resistance, ozone resistance, aging resistance, electrical insulation, and corrosion resistance. EPDM also has a higher cost-effectiveness, a wider temperature range, and better chemical resistance. Without considering hydrothermal aging and ion corrosion, the existing EPDM gaskets are already quite good at dealing with high pressure and oxidation coupling. They can keep the contact surface stress almost unchanged when the joint opening changes slightly, and the aging resistance is also excellent enough under normal temperature conditions. However, when the working environment changes to seawater, its performance is stretched. This is because the traditional EPDM rubber material uses a sulfur vulcanization system and a carbon black, white carbon black, and calcium carbonate filling system, but the vulcanization speed is slow. In the long-term high temperature environment and load use process, it faces thermal oxygen aging and contact stress relaxation, which leads to elastic seal failure. Therefore, EPDM (ethylene propylene diene monomer rubber) is also facing more severe working conditions such as "high water pressure, thermal oxygen, and ion corrosion" in cross-sea shield tunnel applications. Its long-term thermal oxygen, water immersion, and ion corrosion will directly cause changes in material functional groups and breaks in molecular chains, leading to aging of rubber materials and a decline in comprehensive mechanical properties, thereby affecting its sealing effect.

[0006] In summary, the service environment of submarine tunnels is very harsh, and the existing technology is not sufficient to cope with the problem of significant degradation of EPDM performance under the combined effects of high temperature, compressive stress, hydrothermal aging and ion corrosion. Therefore, it is urgent to propose a modified EPDM rubber material with high resilience and low compression deformation that is resistant to seawater corrosion and a preparation method. Summary of the invention

[0007] The present invention aims at the existing technical deficiencies of EPDM rubber sealing materials and provides a modified EPDM rubber material with high resilience and low compression deformation resistant to seawater erosion, as well as a preparation method and application. The present invention starts from the perspective of formula design and specifically improves the EPDM's resistance to high temperature thermal oxidation aging, water-heat aging and compression permanent deformation in a high-concentration seawater environment.

[0008] In order to achieve the above-mentioned object, the first aspect of the present invention provides a modified EPDM rubber material with high resilience and low compression deformation resistant to seawater erosion, wherein the modified EPDM rubber material comprises the following components: EPDM rubber, polyolefin elastomer (POE), filler, processing aid, tackifying resin and anti-aging agent, and at least one of a softening dispersant, a vulcanizing agent, an accelerator and a scorch retarder;

[0009] The processing aid includes zinc methacrylate (ZDMA);

[0010] The accelerator includes p-benzoquinone dioxime (MSDS);

[0011] The anti-aging agent includes 2,6-di-tert-butyl-4-methylphenol (BHT).

[0012] In the present invention, the present invention introduces reactive zinc methacrylate ZDMA through reactive in-situ crosslinking and nano-enhancement technology, which can not only activate the vulcanization system, participate in the vulcanization reaction in situ, form an ionic bond crosslinking network and a covalent bond crosslinking network, and accelerate the vulcanization speed, but also self-polymerize to form nano-scale polysalt ions PZDMA to play a nano-reinforcement role, which can greatly improve the mechanical properties and aging resistance of EPDM, and reduce the compression deformation and contact stress relaxation during long-term load use. As a preferred embodiment, when the filler includes carbon black, the reactive zinc methacrylate ZDMA and carbon black can be used together to reinforce EPDM to form a double filler network, and the synergistic effect of the two can give EPDM high hardness, high elasticity, high strength, low internal friction, high elongation and other characteristics.

[0013] According to the present invention, preferably, the modified EPDM rubber material comprises the following components in parts by weight: 90-110 parts of EPDM rubber, 10-50 parts of polyolefin elastomer, 70-150 parts of filler, 2-20 parts of processing aid, 3-10 parts of tackifying resin, 5-10 parts of anti-aging agent, 0-15 parts of softening dispersant, 0-5 parts of vulcanizing agent, 0-15 parts of accelerator and 0-2 parts of scorch retarder.

[0014] According to the present invention, preferably, the modified EPDM rubber material comprises the following components in parts by weight: 95-105 parts of EPDM rubber, 25-50 parts of polyolefin elastomer, 70-150 parts of filler, 8-20 parts of processing aid, 3-10 parts of tackifying resin, 5-10 parts of anti-aging agent, 0-15 parts of softening dispersant, 0-5 parts of vulcanizing agent, 0-15 parts of accelerator and 0-2 parts of scorch retarder.

[0015] In the present invention, the polyolefin elastomer (POE) added in the present invention can improve the resilience of the modified EPDM rubber material of the present invention and reduce its compression deformation rate under different temperature ranges and working environments. The polyolefin elastomer has good compatibility with EPDM rubber, and its relatively narrow molecular weight distribution gives it better fluidity, which helps to improve the filler dispersion in the rubber matrix; the excellent thermoplasticity of the polyolefin elastomer can improve the thermal processing performance of the rubber material, and its excellent resilience and stiffness help to improve the elastic recovery ability of the modified EPDM rubber material product of the present invention and reduce its compression deformation rate under long-term load; at the same time, the main chain of the POE polyolefin elastomer is a fully saturated structure, with excellent high and low temperature resistance, aging resistance, and ozone resistance; the introduction of POE can effectively improve the tensile strength, elongation at break and aging resistance of the rubber composite material of the present invention.

[0016] According to the present invention, preferably, the Mooney viscosity ML (1+4) 121°C of the polyolefin elastomer is not greater than 40, and the Vicat softening point is not higher than 100°C.

[0017] According to the present invention, preferably, the filler comprises mica powder, and optionally at least one of carbon black, calcium carbonate, white carbon, clay and talc.

[0018] The addition of multiple fillers in the present invention can not only effectively reduce the production cost, but also help to evenly disperse the various components of the rubber during the processing and mixing process, thereby improving the processability of the rubber; as a preferred solution, the addition of carbon black can play a role in filling and reinforcing the rubber, giving the mixed rubber and the vulcanized rubber excellent tensile strength and elongation at break; the addition of calcium carbonate and clay can effectively play a role in increasing volume and reducing costs; the addition of white carbon black can not only play a role in nano-reinforcement, but also effectively improve the hardness of the rubber, which helps to improve the ability of the rubber to resist external deformation; the addition of mica powder can improve the cohesive bonding between the rubber and the filler.

[0019] Since the EPDM rubber in the present invention lacks active groups in its molecular structure, has low cohesive energy, and has poor self-adhesiveness and mutual adhesiveness, the tackifier resin is added to improve the cohesive force of the EPDM rubber and its mixing compatibility with fillers. According to the present invention, preferably, the tackifier resin is selected from at least one of C5 petroleum resin, C9 petroleum resin, rosin resin and terpene resin.

[0020] In the present invention, the softening dispersant is used to improve the processing performance and use performance of rubber, increase the plasticity of the rubber, reduce the viscosity of the rubber and the temperature during mixing, improve its dispersibility and miscibility with inorganic fillers, and improve the tensile strength, elongation and wear resistance of the vulcanized rubber. According to the present invention, preferably, the softening dispersant is selected from at least one of paraffin oil, naphthenic oil, aromatic oil, rosin oil, soybean oil, liquid polyisobutylene and liquid EPDM rubber.

[0021] According to the present invention, preferably, the vulcanizing agent is a mixture of sulfur and a peroxide vulcanizing agent, and the peroxide vulcanizing agent is 2,4-di-tert-butyl cumene peroxide (BIBP) and / or dicumyl peroxide (DCP).

[0022] According to the present invention, preferably, the scorch retarder is N-cyclohexylthiophthalimide (CTP) and / or N-nitrosodiphenylamine (NDPA).

[0023] According to the present invention, preferably, the processing aid further comprises at least one of zinc oxide, stearic acid and zinc stearate.

[0024] According to the present invention, preferably, the accelerator further comprises at least one of trimethallyl isocyanate (H-2), triallyl isocyanurate (TAIC), N,N'-m-phenylene bismaleimide (HVA-2) and trimethylolpropane methacrylate (TMPTMA).

[0025] In the present invention, the introduced accelerator can work synergistically with the vulcanizing agent to increase the number and strength of the cross-linked network in the rubber after vulcanization, improve the mechanical properties and resilience of the rubber, and reduce its compression deformation rate. The accelerator p-benzoquinone dioxime can participate in the vulcanization reaction and improve the thermal oxidation stability of the rubber.

[0026] According to the present invention, preferably, the antioxidant also includes at least one of N-isopropyl-N'-phenyl-p-phenylenediamine (anti-4010NA), N-(1-methylisopentyl)-N'-phenyl-p-phenylenediamine (anti-4020), N,N'-bis(1,4-dimethylpentyl)-p-phenylenediamine (anti-4030) and 2,2,4-trimethyl-1,2-dihydroquinoline (anti-aging agent RD).

[0027] The second aspect of the present invention provides a method for preparing the modified EPDM rubber material with high resilience and low compression deformation and resistant to seawater erosion, the method comprising the following steps:

[0028] The EPDM rubber is put into an internal mixer for plasticization to obtain a plasticized rubber; the plasticized rubber, a tackifying resin, an anti-aging agent, a processing aid and an optional anti-scorching agent are mixed in the internal mixer to obtain a first mixed product; the first mixed product, a polyolefin elastomer, a filler and an optional softening dispersant are mixed in the internal mixer to obtain a second mixed product; the second mixed product is sent to an open mixer for open mixing to obtain a masterbatch;

[0029] The first-stage masterbatch is put into an internal mixer for plastication to obtain a plasticized masterbatch; the plasticized masterbatch, an optional vulcanizing agent and an optional accelerator are mixed in the internal mixer to obtain a mixed rubber material; the mixed rubber material is sent to an open mixer for open mixing to obtain a second-stage mixed rubber material;

[0030] The second-stage mixed rubber is vulcanized to obtain the modified EPDM rubber material with high resilience and low compression deformation and resistance to seawater corrosion.

[0031] According to the present invention, preferably, the operating parameters of the internal mixer include: initial temperature 60-80° C., rotor speed 30-40 r / min, filling factor 0.6-0.8.

[0032] According to the present invention, preferably, the operating parameters of the mixing mill include: an initial temperature below 60°C.

[0033] According to the present invention, preferably, the time of the vulcanization treatment is obtained by placing the two-stage mixed rubber in a vulcanizer for ≥24 hours and testing at 180°C; the pressure of the vulcanization treatment is 5-10MPa.

[0034] In the present invention, as a preferred embodiment, the preparation method of the modified EPDM rubber material with high resilience and low compression deformation and resistant to seawater erosion comprises the following steps:

[0035] S1: Put the EPDM rubber into an internal mixer, and perform plasticization at 55-65°C for 3-5 minutes to obtain plasticized rubber; mix the plasticized rubber, tackifying resin, anti-aging agent, processing aid and optional anti-scorching agent in the internal mixer for 5-10 minutes to obtain a first mixture; then mix the first mixture, polyolefin elastomer, filler and optional softening dispersant in the internal mixer for 10 minutes or until the components are mixed into a uniform state to obtain a second mixture, and discharge the rubber at 135-145°C; send the second mixture into an open mixer, thinly pass and pack, the roller distance of the first open mixer is 2-3mm, and the plate is dropped 3 times; adjust the film thickness to 4±2mm in the second open mixer, perform 3 / 4 tapping 6 times, and the film is 4mm to obtain a masterbatch;

[0036] S2: putting the first-stage masterbatch into an internal mixer, and performing plastication at 45-55° C. for 3-5 minutes to obtain a plasticized masterbatch; mixing the plasticized masterbatch, an optional vulcanizing agent, and an optional accelerator in the internal mixer, at a mixing temperature not exceeding 100° C., for 10-15 minutes to obtain a mixed rubber material, and removing the rubber material; sending the mixed rubber material into an open mixer, thinly passing and packing, with a first-stage mixing roller distance of 2-3mm, and dropping the rubber sheet 3 times; adjusting the rubber sheet thickness to 4±2mm for the second-stage mixing, performing 3 / 4 rubber tapping 6 times, and removing the rubber sheet 4mm, to obtain a second-stage mixed rubber;

[0037] S3: After the two-stage mixed rubber is placed in a vulcanizer for ≥24 hours, it is sent to the vulcanizer and the vulcanization time is obtained by testing at 180°C; after the two-stage mixed rubber is placed in a flat vulcanizer mold for ≥24 hours, it is vulcanized according to the vulcanization time obtained by the test, and the vulcanization pressure is 5-10MPa, so as to obtain the modified EPDM rubber material with high resilience and low compression deformation that is resistant to seawater erosion.

[0038] The third aspect of the present invention provides the use of the modified EPDM rubber material with high resilience and low compression deformation and resistance to seawater erosion in sealing between segments of an undersea tunnel.

[0039] The beneficial effects of the technical solution of the present invention are as follows: the present invention innovatively introduces the processing aid zinc methacrylate ZDMA by modifying the formula design of EPDM, and constructs multiple three-dimensional cross-linked networks (ionic bond cross-linked networks and covalent bond cross-linked networks) in the rubber through reactive in-situ cross-linking and nano-enhancement technology; at the same time, the present invention introduces high-resilience polyolefin elastomer POE and lamellar structure reinforcing filler mica powder, and then through the effective ratio and synergistic effect with p-benzoquinone dioxime MSDS and anti-aging agent BHT, the rubber composite material has excellent resistance to thermal oxidation aging, which can greatly improve the aging resistance and resistance to external deformation of the modified EPDM rubber material, reduce the compression deformation and contact stress relaxation during long-term load use, thereby solving the stress relaxation and elastic sealing failure problems of rubber sealing materials under long-term high temperature load in harsh working conditions (cross-sea shield tunnels, thermal oxidation aging, hot water and seawater immersion). Specifically:

[0040] (1) The present invention mainly prepares a high-performance EPDM rubber sealing material that is resistant to heat and oxygen aging, seawater erosion and aging, and has a low compression deformation rate. Compared with traditional vulcanized rubber, the product of the present invention uses a sulfur and peroxide co-vulcanization system, innovatively introduces a processing aid zinc methacrylate ZDMA, and constructs a multiple three-dimensional cross-linked network (ionic bond cross-linked network and covalent bond cross-linked network) in the rubber through reactive in-situ cross-linking and nano-enhancement technology, which can greatly improve the mechanical properties of EPDM and its aging resistance, and reduce the compression deformation and contact stress relaxation during long-term load use.

[0041] (2) The present invention introduces high-rebound polyolefin elastomer POE and mica powder as a reinforcing filler with a lamellar structure. The introduction of POE elastomer can greatly improve the stiffness and resilience of the EPDM rubber composite material, improve its ability to resist external deformation, and reduce the compression deformation rate under high and low temperatures; the unique high diameter-to-thickness ratio and lamellar structure of mica powder can improve the reinforcement effect and air tightness, and the polarization effect of its own mineral crystals and the interference effect of water molecules between layers can effectively shield ultraviolet rays, microwaves, and infrared rays, greatly improving the aging resistance of the product.

[0042] (3) The present invention can further improve the anti-oxidation and anti-aging properties of rubber through the effective ratio and synergistic effect of the accelerator benzoquinone dioxime MSDS and the anti-aging agent BHT, achieve excellent anti-thermal oxidative aging properties of the rubber composite material, and effectively inhibit the oxidative degradation of the modified EPDM rubber obtained by the present invention, thereby effectively improving its durability and extending its service life.

[0043] Other features and advantages of the present invention will be described in detail in the following detailed description. DETAILED DESCRIPTION

[0044] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to make the present invention more thorough and complete, and to fully convey the scope of the present invention to those skilled in the art.

[0045] In the following embodiments and comparative examples:

[0046] EPDM4570 purchased from Dow Chemical of the United States;

[0047] The polyolefin elastomer was purchased from POE8480 of Dow Chemical of the United States;

[0048] Stearic acid was purchased from SA1840 of Hangzhou Oil Chemical Co., Ltd., and zinc methacrylate ZDMA was purchased from Hubei Shineng Chemical Technology Co., Ltd.;

[0049] Terpene resin was purchased from Guangzhou Songbao Chemical Co., Ltd.;

[0050] 2,2,4-trimethyl-1,2-dihydroquinoline (anti-aging agent RD) was purchased from Ningbo Aikemu New Materials Co., Ltd., N-isopropyl-N'-phenyl-p-phenylenediamine (anti-4010NA) was purchased from Ningbo Aikemu New Materials Co., Ltd., and 2,6-di-tert-butyl-4-methylphenol (BHT) was purchased from MIANOX BHT of Nanjing Milan Chemical Co., Ltd.;

[0051] Paraffin oil was purchased from Shandong Taichang Petrochemical Technology Co., Ltd. Paraffin oil-100#;

[0052] Dicumyl peroxide (DCP) was purchased from Guangzhou Fangruida Chemical Co., Ltd.;

[0053] p-Benzoquinone dioxime (MSDS) was purchased from Tianyuan Aviation Materials (Yingkou) Technology Co., Ltd., and triallyl isocyanurate (TAIC) was purchased from Guangzhou Fangruida Chemical Co., Ltd. TAICS;

[0054] N-Nitrosodiphenylamine (NDPA) was purchased from MacLean Chemical Co., Ltd.

[0055] Example 1

[0056] This embodiment provides a modified EPDM rubber material with high resilience and low compression deformation and resistance to seawater erosion. The modified EPDM rubber material includes the following components in parts by weight:

[0057] 100 parts of EPDM, 30 parts of POE,

[0058] Filler (carbon black 50 parts, white carbon black 10 parts, calcium carbonate 40 parts, mica powder 20 parts),

[0059] Processing aids (5 parts of zinc oxide, 3 parts of stearic acid, 10 parts of zinc methacrylate ZDMA), tackifying resin (4 parts of terpene resin),

[0060] Anti-aging agent (anti-aging agent RD 2 parts, anti-aging agent 4010NA 2 parts, 2,6-di-tert-butyl-4-methylphenol (BHT) 2 parts),

[0061] Softening dispersant (paraffin oil 8 parts),

[0062] Curing agent (2 parts of dicumyl peroxide (DCP), 0.5 parts of sulfur),

[0063] Accelerator (1 part of p-benzoquinone dioxime (MSDS), 1 part of TAIC),

[0064] Anti-scorch agent (NDPA 0.5 parts).

[0065] The preparation method of the modified EPDM rubber material with high resilience and low compression deformation and resistant to seawater erosion comprises the following steps:

[0066] S1: Put the EPDM rubber into an internal mixer, and perform plasticization at 60°C for 5 minutes to obtain plasticized rubber; mix the plasticized rubber, tackifying resin, anti-aging agent, processing aid, and anti-scorching agent in the internal mixer for 10 minutes to obtain a first mixture; then mix the first mixture, polyolefin elastomer, filler, and softening dispersant in the internal mixer for 10 minutes or until the components are mixed into a uniform state to obtain a second mixture, and discharge the rubber at 140°C; send the second mixture into an open mixer, thinly pass and pack, the roller distance of the first open mixer is 2mm, and the plate is dropped 3 times; adjust the film thickness to 4±2mm in the second open mixer, perform 3 / 4 tapping 6 times, and the film is 4mm to obtain a masterbatch;

[0067] S2: putting the first-stage masterbatch into an internal mixer, and performing plastication at 50° C. for 5 min to obtain a plasticized masterbatch; mixing the plasticized masterbatch, a vulcanizing agent and an accelerator in the internal mixer at a mixing temperature not exceeding 100° C. for 15 min to obtain a mixed rubber material, and removing the rubber material; sending the mixed rubber material into an open mixer, thinly passing and packing, the first-stage mixing roller distance is 3 mm, and the plate is dropped 3 times; the second-stage mixing is performed to adjust the rubber sheet thickness to 4±2 mm, and 3 / 4 rubber tapping is performed 6 times, and the sheet is 4 mm, to obtain a second-stage mixed rubber;

[0068] S3: After the two-stage mixed rubber is left to stand for 24 hours, it is sent to a vulcanizer and tested at 180°C to obtain the vulcanization treatment time; after the two-stage mixed rubber is left to stand for 24 hours, it is placed in a flat vulcanizer mold and vulcanized according to the vulcanization treatment time obtained by the test. The vulcanization treatment pressure is 15 MPa, and the modified EPDM rubber material with high resilience and low compression deformation that is resistant to seawater erosion is obtained.

[0069] Compared with Example 1, wherein:

[0070] The modified EPDM rubber material of Example 2 increases the amount of POE and ZDMA;

[0071] The modified EPDM rubber material of Example 3 does not contain mica powder;

[0072] The modified EPDM rubber material of Comparative Example 1 does not contain polyolefin elastomer POE;

[0073] The modified EPDM rubber material of Comparative Example 2 does not contain zinc methacrylate ZDMA;

[0074] The modified EPDM rubber material of Comparative Example 3 did not add the accelerator MSDS;

[0075] Comparative Example 4 uses a sulfur vulcanization system, but does not add POE, ZDMA, BHT and MSDS.

[0076] The modified EPDM rubber material of Comparative Example 5 does not contain the anti-aging agent BHT (2,6-di-tert-butyl-4-methylphenol);

[0077] The formulas of the modified EPDM rubber materials of the above-mentioned embodiments and comparative examples are shown in Table 1.

[0078] Table 1

[0079]

[0080]

[0081] Test Case

[0082] In this test example, the rubber materials of Examples 1-3 and Comparative Examples 1-5 were tested for performance, including tensile performance, tearing performance, hardness, and compression deformation performance under different test environments; the test results are shown in Table 2.

[0083] Test 1: Tensile properties

[0084] According to GB / T 528-2009 “Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber”, the tensile strength (MPa) of the sound insulation layer rubber prepared in each embodiment and each comparative example was tested.

[0085] Test 2: Tearing performance

[0086] The tear strength (N / mm) of the sound insulation layer rubber prepared in each embodiment and each comparative example was tested according to GB / T 529-2008 “Determination of tear strength of vulcanized rubber or thermoplastic rubber”.

[0087] Test 3: Hardness

[0088] The Shore hardness of the sound insulation layer rubber prepared in each embodiment and each comparative example was tested according to GB / T 531.1-2008 “Test method for indentation hardness of vulcanized rubber or thermoplastic rubber”.

[0089] Test 4: Compression set

[0090] According to GB / T 7759.1-2015 “Determination of compression permanent set of vulcanized rubber or thermoplastic rubber”, the elasticity retention ability of the sound insulation layer rubber prepared in each embodiment and each comparative example after continuous compression under different experimental environments was tested.

[0091] A) High temperature compression deformation: The sample was placed in a stopper mold with a compression deformation of 25%, placed in a 70°C blast oven for 24 hours, then taken out and tested for its compression deformation rate after recovery for 30 minutes at standard test room temperature;

[0092] B) High-temperature water treatment compression deformation: The sample is placed in a stopper mold with a 25% compression deformation. The compression deformation mold is placed in a constant temperature water tank at 70°C for 24 hours, then taken out and wiped dry. The compression deformation rate is tested after recovery at the standard test room temperature for 30 minutes.

[0093] B) High-temperature artificial seawater compression deformation: According to ASTM D41141-98 (2021), an artificial seawater solution is prepared: 1L pure water + 24.5g NaCl + 4.1g Na2SO4 + 11.1g MgCl2·6H2O + 1.1g CaCl2. The sample is placed in a limiter mold with 25% compression deformation. The compression deformation mold is placed in a constant temperature artificial seawater solution at 70°C for 24 hours, then taken out and wiped dry. The compression deformation rate is tested after recovery at the standard test room temperature for 30 minutes.

[0094] Table 2

[0095]

[0096]

[0097] According to the results in Table 2, we can see that:

[0098] The examples 1 and 2, which introduce POE, ZDMA, MSDS, BHT and mica powder and select DCP (dicumyl peroxide) and sulfur co-vulcanization system, all have good comprehensive performance and resilience, and their high temperature compression change, hot water compression change and high temperature artificial seawater compression change rates are all within 25%, which is mainly attributed to the formation of more effective multiple cross-linked networks (ionic bond cross-linked networks and covalent bond cross-linked networks) by ZDMA homopolymerization and self-polymerization. And due to the effective ratio and synergistic effect of MSDS and BHT with other anti-aging agents, the thermal oxidation aging resistance of the modified EPDM rubber material in a high temperature environment is effectively improved, and a low compression deformation rate is achieved.

[0099] Compared with Example 1, Example 3 does not add mica powder, and its comprehensive performance is not much different from that of Example 1, but the compression deformation rate is slightly increased; Comparative Example 5 does not add the anti-aging agent BHT, and the thermal aging degradation of the rubber material under high temperature for a long time leads to an increase in the compression deformation rate.

[0100] Comparative Example 1 is not filled with high-resilience polyolefin elastomer POE, and its compression deformation rate under different test environments is higher than that of Example 1;

[0101] Comparative Example 2 does not add ZDMA, and its compression deformation rate under high temperature, hot water and high temperature artificial seawater environments is significantly higher than that of Example 1. This is attributed to the fact that the rubber material with added ZDMA can form a larger number of cross-linked networks, which has a better ability to resist external deformation;

[0102] Comparative Example 3 did not add the accelerator MSDS, and its thermal oxygen stability was poor, resulting in a significant increase in the compression deformation rate under high temperature environment;

[0103] Comparative Example 4 uses a single sulfur vulcanization system without adding functional additives such as POE, ZDMA, MSDS, and BHT. Its compression deformation rates under different high temperature environments are all above 25%, and some are as high as above 35%, which is difficult to meet the high rebound and sealing effects required under harsh working conditions.

[0104] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A modified EPDM rubber material with high resilience and low compression deformation and resistant to seawater erosion, characterized in that: The modified EPDM rubber material comprises the following components: EPDM rubber, polyolefin elastomer, filler, processing aid, tackifying resin and anti-aging agent, and optionally at least one of a softening dispersant, a vulcanizing agent, an accelerator and a scorch retarder; The processing aid includes zinc methacrylate; The accelerator includes p-benzoquinone dioxime; The anti-aging agent includes 2,6-di-tert-butyl-4-methylphenol.

2. The modified EPDM rubber material with high resilience and low compression deformation and resistant to seawater erosion according to claim 1, wherein: The modified EPDM rubber material comprises the following components in parts by weight: 90-110 parts of EPDM rubber, 10-50 parts of polyolefin elastomer, 70-150 parts of filler, 2-20 parts of processing aid, 3-10 parts of tackifying resin, 5-10 parts of anti-aging agent, 0-15 parts of softening dispersant, 0-5 parts of vulcanizing agent, 0-15 parts of accelerator and 0-2 parts of scorch retarder.

3. The modified EPDM rubber material with high resilience and low compression deformation and resistant to seawater erosion according to claim 2, wherein: The modified EPDM rubber material comprises the following components in parts by weight: 95-105 parts of EPDM rubber, 25-50 parts of polyolefin elastomer, 70-150 parts of filler, 8-20 parts of processing aid, 3-10 parts of tackifying resin, 5-10 parts of anti-aging agent, 0-15 parts of softening dispersant, 0-5 parts of vulcanizing agent, 0-15 parts of accelerator and 0-2 parts of scorch retarder.

4. The modified EPDM rubber material with high resilience and low compression deformation and resistant to seawater erosion according to any one of claims 1 to 3, wherein: The Mooney viscosity ML (1+4) of the polyolefin elastomer at 121°C is not greater than 40, and the Vicat softening point is not higher than 100°C; The filler comprises mica powder, and optionally at least one of carbon black, calcium carbonate, white carbon black, clay and talc; The tackifying resin is selected from at least one of C5 petroleum resin, C9 petroleum resin, rosin resin and terpene resin; The softening dispersant is selected from at least one of paraffin oil, naphthenic oil, aromatic oil, rosin oil, soybean oil, liquid polyisobutylene and liquid EPDM rubber; The vulcanizing agent is a mixture of sulfur and a peroxide vulcanizing agent, and the peroxide vulcanizing agent is 2,4-di-tert-butyl peroxide isopropylbenzene and / or diisopropylbenzene peroxide; The scorch retarder is N-cyclohexylthiophthalimide and / or N-nitrosodiphenylamine.

5. The modified EPDM rubber material with high resilience and low compression deformation and resistant to seawater erosion according to any one of claims 1 to 3, wherein: The processing aid further comprises at least one of zinc oxide, stearic acid and zinc stearate.

6. The modified EPDM rubber material with high resilience and low compression deformation and resistant to seawater erosion according to any one of claims 1 to 3, wherein: The accelerator further comprises at least one of trimethallyl isocyanate, triallyl isocyanurate, N,N'-m-phenylene bismaleimide and trimethylolpropane methacrylate.

7. The modified EPDM rubber material with high resilience and low compression deformation and resistant to seawater erosion according to any one of claims 1 to 3, wherein: The anti-aging agent further comprises at least one of N-isopropyl-N'-phenyl-p-phenylenediamine, N-(1-methylisopentyl)-N'-phenyl-p-phenylenediamine, N,N'-bis(1,4-dimethylpentyl)-p-phenylenediamine and 2,2,4-trimethyl-1,2-dihydroquinoline.

8. The method for preparing the modified EPDM rubber material with high resilience and low compression deformation and resistant to seawater erosion according to any one of claims 1 to 7, characterized in that: The preparation method comprises the following steps: The EPDM rubber is put into an internal mixer for plasticization to obtain a plasticized rubber; the plasticized rubber, a tackifying resin, an anti-aging agent, a processing aid and an optional anti-scorching agent are mixed in the internal mixer to obtain a first mixed product; the first mixed product, a polyolefin elastomer, a filler and an optional softening dispersant are mixed in the internal mixer to obtain a second mixed product; the second mixed product is sent to an open mixer for open mixing to obtain a masterbatch; The first-stage masterbatch is put into an internal mixer for plastication to obtain a plasticized masterbatch; the plasticized masterbatch, an optional vulcanizing agent and an optional accelerator are mixed in the internal mixer to obtain a mixed rubber material; the mixed rubber material is sent to an open mixer for open mixing to obtain a second-stage mixed rubber material; The second-stage mixed rubber is vulcanized to obtain the modified EPDM rubber material with high resilience and low compression deformation and resistance to seawater corrosion.

9. The method for preparing the modified EPDM rubber material with high resilience and low compression deformation and resistant to seawater erosion according to claim 8, wherein: The operating parameters of the internal mixer include: initial temperature 60-80°C, rotor speed 30-40r / min, filling factor 0.6-0.8; The operating parameters of the mixing mill include: initial temperature below 60°C; The time of the vulcanization treatment is obtained by placing the two-stage mixed rubber in a vulcanizer for ≥24 hours and testing it at 180° C. The pressure of the vulcanization treatment is 5-10 MPa.

10. Use of the modified EPDM rubber material with high resilience and low compression deformation and resistant to seawater erosion as claimed in any one of claims 1 to 7 in sealing between segments of an undersea tunnel.

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